@article {pmid30439530,
year = {2018},
author = {Shin, NR and Choi, JS},
title = {Manual dexterity and dental biofilm accumulation in independent older adults without hand disabilities: a cross-sectional study.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2018.11.007},
pmid = {30439530},
issn = {1873-1597},
abstract = {BACKGROUND: This study investigated the relationship between manual dexterity and dental biofilm accumulation in independent older Koreans using Quantitative Light-Induced Fluorescence-Digital (QLF-D).<br><br>METHODS: This cross-sectional study included 44 participants recruited from senior welfare facilities in South Korea and aged ≥ 65 years. Participants were surveyed using face-to-face structured interviews; manual dexterity was assessed using the Box and Blocks Test. To evaluate dental biofilm accumulation, the 528 surfaces of six index teeth were imaged using QLF-D and then quantified into Simple Plaque Scores (SPS) and ΔR20 values. The t-test and one-way analysis of variance were used to analyze differences in SPS and ΔR20 according to general characteristics and manual dexterity.<br><br>RESULTS: Those who brushed their teeth ≤ 2 times per day had higher SPS and ΔR20 values on the lingual surface of tooth #24 than those who brushed ≥ 3 times per day (p < 0.05). The low manual dexterity group had higher SPS on lingual surfaces of teeth #12, #24, and #32, as well as higher ΔR20 values on the lingual surfaces of teeth #12, #24, #32, and #44 (p < 0.05) than the normal group.<br><br>CONCLUSIONS: The low manual dexterity group had more dental biofilm-particularly on the lingual surfaces of teeth-and more mature biofilm than the normal group. These findings indicate that reduced manual dexterity could be a predictor of poor oral hygiene in independent older adults without hand disabilities. Therefore, we suggest manual dexterity be assessed in advance of dental biofilm assessment and tooth brushing instruction.},
}
@article {pmid30439400,
year = {2018},
author = {Albano, M and Crulhas, BP and Alves, FCB and Pereira, AFM and Andrade, BFMT and Barbosa, LN and Furlanetto, A and da Silveira Lyra, LP and Rall, VLM and Júnior, AF},
title = {Antibacterial and anti-biofilm activities of cinnamaldehyde against S. epidermidis.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2018.11.009},
pmid = {30439400},
issn = {1096-1208},
abstract = {The search for new antimicrobial drugs has been necessary due to the increased bacterial resistance to antibiotics currently in use, and natural products play an important role in this field. The aim of this study was to evaluate the in vitro effect of cinnamaldehyde on S. epidermidis strains, biofilm set-up prevention, as well as its effect on pre-established biofilms. The minimum inhibitory concentration (MIC) ranged from 300 to 500 μg/mL, and the minimum bactericidal concentration (MBC) from 400 to 600 μg/mL. The biofilm inhibitory concentration and biofilm eradication concentration values were four-fold (clinical isolate) and eight-fold (ATCC strain) greater than the concentration required to inhibit planktonic growth. Sub-inhibitory concentrations of cinnamaldehyde attenuated biofilm formation of S. epidermidis strains on polystyrene microtiter plates. The combination of cinnamaldehyde and linezolid was able to inhibit S. epidermidis with a bactericidal effect. Further investigation of the mechanism of action of cinnamaldehyde revealed its effect on the cell membrane permeability, and confocal laser scanning microscopy (CLSM) images illustrated the impact of cinnamaldehyde in the detachment and killing of existing biofilms. Thereby, our data confirmed the ability of cinnamaldehyde to reduce bacterial planktonic growth of S. epidermidis, inhibiting biofilm formation and eradicating pre-formed biofilm.},
}
@article {pmid30433856,
year = {2018},
author = {Uğur, S and Akçelik, N and Yüksel, FN and Taşkale Karatuğ, N and Akçelik, M},
title = {Effects of dam and seqA genes on biofilm and pellicle formation in Salmonella.},
journal = {Pathogens and global health},
volume = {},
number = {},
pages = {1-10},
doi = {10.1080/20477724.2018.1539803},
pmid = {30433856},
issn = {2047-7732},
abstract = {In this study, the effects of dam and seqA genes on the formation of pellicle and biofilm was determined using five different Salmonella serovars S. Group C1 (DMC2 encoded), S. Typhimurium (DMC4 encoded), S. Virchow (DMC11 encoded), S. Enteritidis (DMC22 encoded), and S. Montevideo (DMC89 encoded). dam and seqA mutants in Salmonella serovars were performed by the single step lambda red recombination method. The mutants obtained were examined according to the properties of biofilm on the polystyrene surfaces and the pellicle formation on the liquid medium. As a result of these investigations, it was determined that the biofilm formation properties on polystyrene surfaces decreased significantly (p < 0.05) in all tested dam and seqA mutants, while the pellicle formation properties were lost in the liquid medium. When pBAD24 vector, containing the dam and seqA genes cloned behind the inducible arabinose promoter, transduced into dam and seqA mutant strains, it was determined that the biofilm formation properties on the polystyrene surfaces reached to the natural strains' level in all mutant strains. Also, the pellicle formation ability was regained in the liquid media. All these data demonstrate that dam and seqA genes play an important role in the formation of biofilm and pellicle structures in Salmonella serovars.},
}
@article {pmid30431405,
year = {2018},
author = {Palmieri, V and Bugli, F and Cacaci, M and Perini, G and Maio, F and Delogu, G and Torelli, R and Conti, C and Sanguinetti, M and Spirito, M and Zanoni, R and Papi, M},
title = {Graphene oxide coatings prevent Candida albicans biofilm formation with a controlled release of curcumin-loaded nanocomposites.},
journal = {Nanomedicine (London, England)},
volume = {},
number = {},
pages = {},
doi = {10.2217/nnm-2018-0183},
pmid = {30431405},
issn = {1748-6963},
abstract = {AIM: Fabrication of graphene oxide (GO)-based medical devices coatings that limit adhesion of Candida albicans, a main issue of healthcare-associated infections.<br><br>METHODS: The GO composites noncovalently functionalized with curcumin (CU), a hydrophobic molecule with active antimicrobial action, polyethylene glycol (PEG) that hinders the absorption of biomolecules or a combination of CU and PEG (GO-CU-PEG) were drop-casted on surfaces and antifungal efficacy was assessed.<br><br>RESULTS: We demonstrate that GO-CU-PEG coatings can reduce fungal adhesion, proliferation and biofilm formation. Furthermore, in an aqueous environment, surfaces release curcumin-PEG nanocomposites that have a minimum inhibitory concentration of 9.25 μg/ml against C. albicans.<br><br>CONCLUSION: Prevention of early cell adhesion and creation of a proximal environment unfavorable for growth make these GO-supported biomaterials attractive for innovative medical device manufacturing.},
}
@article {pmid30430938,
year = {2018},
author = {de Macêdo Andrade, AC and Rosalen, PL and Freires, IA and Scotti, L and Scotti, MT and Aquino, SG and de Castro, RD},
title = {Antifungal activity, mode of action, docking prediction and anti-biofilm effects of (+)-β-pinene enantiomers against Candida spp.},
journal = {Current topics in medicinal chemistry},
volume = {},
number = {},
pages = {},
doi = {10.2174/1568026618666181115103104},
pmid = {30430938},
issn = {1873-4294},
abstract = {AIMS: The objective of this study was to investigate the effectiveness of (+)-β-pinene inhibition onCandida spp. growth,aiming at elucidation of the mechanism of action; to determinefungal cell enzymebinding activity (through molecular docking simulations) and its effects on biofilm reduction.<br><br>METHODOLOGY: Candidastrains (n=26)from referencedand clinical origins, eithersusceptible or resistant to standard clinical antifungals, were tested for determination of Minimum Inhibitory Concentration (MIC); Minimum Fungicidal Concentration (MFC); and microbial death curves upon treatment with (+)-β-pinene; the effects of (+)-β-pinene on the cell wall (sorbitol assay), membrane ergosterol binding, and effects on biofilm wereevaluatedby microdilution techniques. We also evaluated the interactions between (+)-β-pinene and cell wall and membrane enzymes of interest.<br><br>RESULTS: The MIC values of (+)-β-pinene ranged from <56.25 to 1800 µmol/L. The MIC of (+)-β-pinene did not increase when ergosterol was added to the medium, however it did increase in the presence of sorbitol, leading to a doubled MIC for C. tropicalis and C. krusei. The results of the molecular docking simulationsindicatedbetter interactionwith delta-14-sterol reductase (-51 kcal/mol). (+)-β-pinene presents anti-biofilm activity againstmultiples species of Candida.<br><br>CONCLUSION: (+)-β-pinene has antifungal activityand most likely acts throughinterference with the cell wall; through molecular interaction with Delta-14-sterol reductase and, to a lesser extent, with the 1,3-β-glucan synthase.This molecules was also found to effectively reduceCandida biofilm adhesion.},
}
@article {pmid30429505,
year = {2018},
author = {Inaba, T and Hori, T and Aizawa, H and Sato, Y and Ogata, A and Habe, H},
title = {Microbiomes and chemical components of feed water and membrane-attached biofilm in reverse osmosis system to treat membrane bioreactor effluents.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {16805},
doi = {10.1038/s41598-018-35156-2},
pmid = {30429505},
issn = {2045-2322},
abstract = {Reverse osmosis (RO) system at a stage after membrane bioreactor (MBR) is used for the wastewater treatment and reclamation. One of the most serious problems in this system is membrane fouling caused by biofilm formation. Here, microbiomes and chemical components of the feed water and membrane-attached biofilm of RO system to treat MBR effluents were investigated by non-destructive confocal reflection microscopy, excitation-emission fluorescence spectroscopy and high-throughput sequencing of 16S rRNA genes. The microscopic visualization indicated that the biofilm contained large amounts of microbial cells (0.5 ± 0.3~3.9 ± 2.3 µm3/µm2) and the extracellular polysaccharides (3.3 ± 1.7~9.4 ± 5.1 µm3/µm2) and proteins (1.0 ± 0.2~1.3 ± 0.1 µm3/µm2). The spectroscopic analysis identified the humic and/or fulvic acid-like substances and protein-like substances as the main membrane foulants. High-throughput sequencing showed that Pseudomonas spp. and other heterotrophic bacteria dominated the feed water microbiomes. Meanwhile, the biofilm microbiomes were composed of diverse bacteria, among which operational taxonomic units related to the autotrophic Hydrogenophaga pseudoflava and Blastochloris viridis were abundant, accounting for up to 22.9 ± 4.1% and 3.1 ± 0.4% of the total, respectively. These results demonstrated that the minor autotrophic bacteria in the feed water played pivotal roles in the formation of polysaccharide- and protein-rich biofilm on RO membrane, thereby causing membrane fouling of RO system.},
}
@article {pmid30428566,
year = {2018},
author = {Suzuki, I and Shimizu, T and Senpuku, H},
title = {Role of SCFAs for Fimbrillin-Dependent Biofilm Formation of Actinomyces oris.},
journal = {Microorganisms},
volume = {6},
number = {4},
pages = {},
doi = {10.3390/microorganisms6040114},
pmid = {30428566},
issn = {2076-2607},
abstract = {Actinomyces oris expresses type 1 and 2 fimbriae on the cell surface. Type 2 fimbriae mediate co-aggregation and biofilm formation and are composed of the shaft fimbrillin FimA and the tip fimbrillin FimB. Short-chain fatty acids (SCFAs) are metabolic products of oral bacteria, but the effects of exogenous SCFAs on FimA-dependent biofilm formation are poorly understood. We performed two types of biofilm formation assays using A. oris MG1 or MG1.ΔfimA to observe the effects of SCFAs on FimA-dependent biofilm formation in 96-well and six-well microtiter plates and a flow cell system. SCFAs did not induce six- and 16-hour biofilm formation of A. oris MG1 and MG1.ΔfimA in saliva-coated 96-well and six-well microtiter plates in which metabolites produced during growth were not excluded. However, 6.25 mM butyric acid and 3.125 mM propionic acid induced FimA-dependent biofilm formation and cell death in a flow cell system in which metabolites produced during growth were excluded. Metabolites produced during growth may lead to disturbing effects of SCFAs on the biofilm formation. The pure effects of SCFAs on biofilm formation were induction of FimA-dependent biofilm formation, but the stress responses from dead cells may regulate its effects. Therefore, SCFA may play a key role in A. oris biofilm formation.},
}
@article {pmid30427797,
year = {2018},
author = {Rathnaweera, SS and Rusten, B and Korczyk, K and Helland, B and Rismyhr, E},
title = {Novel biofilm reactor for denitrification of municipal wastewater.},
journal = {Water science and technology : a journal of the International Association on Water Pollution Research},
volume = {78},
number = {7},
pages = {1566-1575},
doi = {10.2166/wst.2018.433},
pmid = {30427797},
issn = {0273-1223},
abstract = {A pilot-scale CFIC® (continuous flow intermittent cleaning) reactor was run in anoxic conditions to study denitrification of wastewater. The CFIC process has already proven its capabilities for biological oxygen demand removal with a small footprint, less energy consumption and low cost. The present study focused on the applicability for denitrification. Both pre-denitrification (pre-DN) and post-denitrification (post-DN) were tested. A mixture of primary treated wastewater and nitrified wastewater was used for pre-DN and nitrified wastewater with ethanol as a carbon source was used for post-DN. The pre-DN process was carbon limited and removal rates of only 0.16 to 0.74 g NOx-N/m²-d were obtained. With post-DN and an external carbon source, 0.68 to 2.2 g NO3-Neq/m²-d removal rates were obtained. The carrier bed functioned as a good filter for both the larger particles coming with influent water and the bio-solids produced in the reactor. Total suspended solids removal in the reactor varied from 20% to 78% (average 45%) during post-DN testing period and 9% to 70% (average 29%) for pre-DN. The results showed that the forward flow washing improves both the DN function and filtration ability of the reactor.},
}
@article {pmid30427559,
year = {2018},
author = {Stabb, EV},
title = {Should they stay or should they go? Nitric oxide and the clash of regulators governing Vibrio fischeri biofilm formation.},
journal = {Molecular microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mmi.14163},
pmid = {30427559},
issn = {1365-2958},
abstract = {A key regulatory decision for many bacteria is the switch between biofilm formation and motile dispersal, and this dynamic is well illustrated in the light-organ symbiosis between the bioluminescent bacterium Vibrio fischeri and the Hawaiian bobtail squid. Biofilm formation mediated by the syp gene cluster helps V. fischeri transition from a dispersed planktonic lifestyle to a robust aggregate on the surface of the nascent symbiotic organ. However, the bacteria must then swim to pores and down into the deeper crypt tissues that they ultimately colonize. A number of positive and negative regulators control syp expression and biofilm formation, but until recently the environmental inputs controlling this clash between opposing regulatory mechanisms have been unclear. Thompson et al. have now shown that Syp-mediated biofilms can be repressed by a well known host-derived molecule: nitric oxide. This regulation is accomplished by the NO sensor HnoX exerting control over the biofilm regulator HahK. The discoveries reported here by Thompson et al. cast new light on a critical early stage of symbiotic initiation in the V. fischeri-squid model symbiosis, and more broadly it adds to a growing understanding of the role(s) that NO and HnoX play in biofilm regulation by many bacteria. This article is protected by copyright. All rights reserved.},
}
@article {pmid30425687,
year = {2018},
author = {Liu, J and Yang, L and Hou, Y and Soteyome, T and Zeng, B and Su, J and Li, L and Li, B and Chen, D and Li, Y and Wu, A and Shirtliff, ME and Harro, JM and Xu, Z and Peters, BM},
title = {Transcriptomics Study on Staphylococcus aureus Biofilm Under Low Concentration of Ampicillin.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {2413},
doi = {10.3389/fmicb.2018.02413},
pmid = {30425687},
issn = {1664-302X},
abstract = {Staphylococcus aureus is one of the representative foodborne pathogens which forms biofilm. Antibiotics are widely applied in livestock husbandry to maintain animal health and productivity, thus contribute to the dissemination of antimicrobial resistant livestock and human pathogens, and pose a significant public health threat. Effect of antibiotic pressure on S. aureus biofilm formation, as well as the mechanism, remains unclear. In this study, the regulatory mechanism of low concentration of ampicillin on S. aureus biofilm formation was elucidated. The viability and biomass of biofilm with and without 1/4 MIC ampicillin treatment for 8 h were determined by XTT and crystal violet straining assays, respectively. Transcriptomics analysis on ampicillin-induced and non-ampicillin-induced biofilms were performed by RNA-sequencing, differentially expressed genes identification and annotation, GO functional and KEGG pathway enrichment. The viability and biomass of ampicillin-induced biofilm showed dramatical increase compared to the non-ampicillin-induced biofilm. A total of 530 differentially expressed genes (DEGs) with 167 and 363 genes showing up- and down-regulation, respectively, were obtained. Upon GO functional enrichment, 183, 252, and 21 specific GO terms in biological process, molecular function and cellular component were identified, respectively. Eight KEGG pathways including &quot;Microbial metabolism in diverse environments&quot;, &quot;S. aureus infection&quot;, and &quot;Monobactam biosynthesis&quot; were significantly enriched. In addition, &quot;beta-lactam resistance&quot; pathway was also highly enriched. In ampicillin-induced biofilm, the significant up-regulation of genes encoding multidrug resistance efflux pump AbcA, penicillin binding proteins PBP1, PBP1a/2, and PBP3, and antimicrobial resistance proteins VraF, VraG, Dlt, and Aur indicated the positive response of S. aureus to ampicillin. The up-regulation of genes encoding surface proteins ClfB, IsdA, and SasG and genes (cap5B and cap5C) which promote the adhesion of S. aureus in ampicillin induced biofilm might explain the enhanced biofilm viability and biomass.},
}
@article {pmid30423413,
year = {2018},
author = {Kelly de Oliveira Lopes, L and de Melo Costa, D and Veiga Tipple, AF and Watanabe, E and Castillo, RB and Hu, H and Deva, AK and Vickery, K},
title = {Surgical instruments complex design as barrier for cleaning effectiveness, favouring biofilm formation.},
journal = {The Journal of hospital infection},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jhin.2018.11.001},
pmid = {30423413},
issn = {1532-2939},
abstract = {AIM: Determine the cumulative effect of 20 cycles of contamination, cleaning (manual or manual followed by automated) and steam sterilisation on high-complex-design reusable surgical instruments (RSI) used for orthopaedic surgery.<br><br>METHOD: New flexible medullary reamers and depth gauges were contaminated by soaking in tryptone soya broth, containing 5% sheep blood and 109CFU/mL of Staphylococcus aureus (ATCC 25923), for 5 minutes. To mimic a worse-case scenario, RSI were dried seven hours and subjected to either a) rinsing in distilled water, b) manual cleaning or c) manual plus automated cleaning (gold standard), and steam sterilisation. The contamination, cleaning and sterilisation cycle was repeated 20 times. Adenosine Triphosphate (ATP) was measured after cleaning procedures, while microbial load and residual protein were measured following the 10th and 20th reprocessing, in triplicate. Scanning electron microscopy (SEM) was used to confirm soil and biofilm presence on the RSI after the 20th reprocessing.<br><br>FINDINGS: Manual and manual plus automated cleaning significantly reduced the amount of ATP and protein residues for all RSI. Viable bacteria were not detected following sterilisation. However, SEM detected soil after automated cleaning, and soil, including biofilms, after manual cleaning.<br><br>CONCLUSION: Soil and/or biofilms were evident on complex-design RSI following 20 cycles of contamination and reprocessing, even using the gold standard method of cleaning. Although the depth gauges could be disassembled, biological residues and biofilm accumulated in its lumen. The current design of these RSI prevents removal of all biological soil and this may have an adverse effect on patient outcome.},
}
@article {pmid30423355,
year = {2018},
author = {He, J and Bao, Y and Li, J and Qiu, Z and Liu, Y and Zhang, X},
title = {Nanocomplexes of Carboxymethyl Chitosan/Amorphous Calcium Phosphate Reduce Oral Bacteria Adherence and Biofilm Formation on Human Enamel Surface.},
journal = {Journal of dentistry},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jdent.2018.11.003},
pmid = {30423355},
issn = {1879-176X},
abstract = {OBJECTIVES: This study investigated the effect of CMC/ACP on oral bacteria adherence and biofilm formation on the enamel surface as well as the underlying mechanism to determine the anti-cariogenic potential of CMC/ACP.<br><br>METHODS: A mineral solution of CMC/ACP was characterised by transmission electron microscope. The bactericidal activity of CMC/ACP was evaluated with the plate count method. An in vitro biofilm model was established on saliva-coated enamel blocks; the effect of CMC/ACP on the adherence of Streptococcus mutans and Streptococcus gordonii to and biofilm formation on these blocks, as well as co-aggregation of Fusobacterium nucleatum was assessed by scanning electron microscopy, crystal violet staining, and confocal microscopy. Bacterial surface charge was estimated with the cytochrome c binding assay and by zeta potential measurement.<br><br>RESULTS: CMC/ACP nanocomplexes inhibited S. mutans and S. gordonii adherence to enamel blocks by 90% and 86% (P < 0.01), respectively, and biofilm formation by 45% and 44% (P < 0.01), respectively, after 24 h without bactericidal activity. CMC/ACP reduced F. nucleatum attachment to streptococcal biofilm by 75% (P < 0.01) while also altering cytochrome c binding to bacteria and reducing the zeta potential of the bacterial suspension.<br><br>CONCLUSIONS: CMC/ACP nanocomplexes inhibit cariogenic bacterial adherence, co-adhesion, and biofilm formation on the enamel surface, possibly by altering bacterial surface charge and enhancing the flocculation effect. As an agent that promotes remineralisation and has anti-cariogenic effects, CMC/ACP can be used to prevent and treat early caries and white spot lesions.},
}
@article {pmid30423345,
year = {2018},
author = {Qayyum, S and Sharma, D and Bisht, D and Khan, AU},
title = {Identification of factors involved in Enterococcus faecalis biofilm under quercetin stress.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2018.11.013},
pmid = {30423345},
issn = {1096-1208},
abstract = {Enterococcus faecalis is a gram positive enteric commensal bacteria or opportunistic pathogen and its infection involves biofilm formation. Quercetin, a plant origin polyphenol was found to inhibit E. faecalis biofilm. Crystal violet assay, SEM and CLSM microscopy confirmed biofilm inhibition by quercetin. Proteomics was used to elucidate the changes occurred in bacterial cell by quercetin treatment. 2D-Electrophorosis and MALDI-TOF analysis revealed that nineteen proteins were differentially expressed in quercetin treated sample. Glycolytic pathways, protein translation-elongation pathways and protein folding pathways were under differential expression after treatment. Real Time-PCR (RT-PCR) validated the proteomic data at genomic level except for the translation elongation factor G which showed opposite data to proteomics. Protein-protein interaction networks constructed using STRING 10.0 demonstrated strong connection of translation-elongation proteins with many important proteins. The results of the comparative analysis indicate that quercetin exerts its inhibitory effect by disturbing glycolytic, protein translation-elongation and protein folding pathways. This disturbs bacterial physiology and stops transition of planktonic cells to biofilm state.},
}
@article {pmid30422688,
year = {2018},
author = {Singh, P and Pandit, S and Beshay, M and Mokkapati, VRSS and Garnaes, J and Olsson, ME and Sultan, A and Mackevica, A and Mateiu, RV and Lütken, H and Daugaard, AE and Baun, A and Mijakovic, I},
title = {Anti-biofilm effects of gold and silver nanoparticles synthesized by the Rhodiola rosea rhizome extracts.},
journal = {Artificial cells, nanomedicine, and biotechnology},
volume = {},
number = {},
pages = {1-14},
doi = {10.1080/21691401.2018.1518909},
pmid = {30422688},
issn = {2169-141X},
abstract = {Bacterial biofilm represents a major problem in medicine. They colonize and damage medical devices and implants and, in many cases, foster development of multidrug-resistant microorganisms. Biofilm development starts by bacterial attachment to the surface and the production of extracellular polymeric substances (EPS). The EPS forms a structural scaffold for dividing bacterial cells. The EPS layers also play a protective role, preventing the access of antibiotics to biofilm-associated microorganisms. The aim of this work was to investigate the production nanoparticles that could be used to inhibit biofilm formation. The applied production procedure from rhizome extracts of Rhodiola rosea is simple and environmentally friendly, as it requires no additional reducing, stabilizing and capping agents. The produced nanoparticles were stable and crystalline in nature with an average diameter of 13-17 nm for gold nanoparticles (AuNPs) and 15-30 nm for silver nanoparticles (AgNPs). Inductively coupled plasma mass spectrometry analysis revealed the concentration of synthesized nanoparticles as 3.3 and 5.3 mg/ml for AuNPs and AgNPs, respectively. Fourier-transform infrared spectroscopy detected the presence of flavonoids, terpenes and phenols on the nanoparticle surface, which could be responsible for reducing the Au and Ag salts to nanoparticles and further stabilizing them. Furthermore, we explored the AgNPs for inhibition of Pseudomonas aeruginosa and Escherichia coli biofilms. AgNPs exhibited minimum inhibitory concentrations of 50 and 100 µg/ml, against P. aeruginosa and E. coli, respectively. The respective minimum bactericidal concentrations were 100 and 200 µg/ml. These results suggest that using the rhizome extracts of the medicinal plant R. rosea represents a viable route for green production of nanoparticles with anti-biofilm effects.},
}
@article {pmid30421690,
year = {2018},
author = {Tahir, S and Chowdhury, D and Legge, M and Hu, H and Whiteley, G and Glasbey, T and Deva, AK and Vickery, K},
title = {Transmission of Staphylococcus aureus from dry surface biofilm (DSB) via different types of gloves.},
journal = {Infection control and hospital epidemiology},
volume = {},
number = {},
pages = {1-5},
doi = {10.1017/ice.2018.285},
pmid = {30421690},
issn = {1559-6834},
abstract = {BACKGROUND: Pathogens can survive for extended periods when incorporated into biofilm on dry hospital surfaces (ie, dry-surface biofilm, DSB). Bacteria within biofilm are protected from desiccation and have increased tolerance to cleaning agents and disinfectants.<br><br>OBJECTIVE: We hypothesized that gloved hands of healthcare personnel (HCP) become contaminated with DSB bacteria and hence may transmit bacteria associated with healthcare-associated infections (HAIs).<br><br>METHOD: Staphylococcus aureus DSB was grown in vitro on coupons in a bioreactor over 12 days with periodic nutrition interspersed with long periods of dehydration. Each coupon had ~107 DSB bacterial cells. Transmission was tested with nitrile, latex, and surgical gloves by gripping DSB-covered coupons then pressing finger tips onto a sterile horse blood agar surface for up to 19 consecutive touches and counting the number of colony-forming units (CFU) transferred. Coupons were immersed in 5% neutral detergent to simulate cleaning, and the experiment was repeated.<br><br>RESULTS: Bacterial cells were readily transmitted by all 3 types of gloves commonly used by HCP. Surprisingly, sufficient S. aureus to cause infection were transferred from 1 DSB touch up to 19 consecutive touches. Also, 6 times more bacteria were transferred by nitrile and surgical gloves than to latex gloves (P <.001). Treating the DSB with 5% neutral detergent increased the transmission rate of DSB bacteria 10-fold.<br><br>CONCLUSION: Staphylococcus aureus incorporated into environmental DSB and covered by extracellular polymeric substances readily contaminates gloved hands and can be transferred to another surface. These results confirm the possibility that DSB contributes to HAI acquisition.},
}
@article {pmid30420846,
year = {2018},
author = {Wu, Y and Ma, Y and Xu, T and Zhang, QZ and Bai, J and Wang, J and Zhu, T and Lou, Q and Götz, F and Qu, D and Zheng, CQ and Zhao, KQ},
title = {Nicotine Enhances Staphylococcus epidermidis Biofilm Formation by Altering the Bacterial Autolysis, Extracellular DNA Releasing, and Polysaccharide Intercellular Adhesin Production.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {2575},
doi = {10.3389/fmicb.2018.02575},
pmid = {30420846},
issn = {1664-302X},
abstract = {Staphylococcus epidermidis is a common bacterial colonizer of human skin and mucous membranes, yet it has emerged as an important nosocomial pathogen largely due to its ability to form biofilms. Tobacco smoke has been demonstrated as a contributor to various infection diseases by improving the biofilm formation of multiple bacterial species; however, the association between tobacco smoke and S. epidermidis biofilm is still unclear. In this study, we tested the effect of nicotine, one of the most active components of tobacco, on S. epidermidis biofilm formation, and we studied the underlying mechanisms. Our results showed that nicotine promoted the biofilm formation of S. epidermidis 1457 strain (SE1457) and enhanced its initial attachment to a polyethylene surface as well as polysaccharide intercellular adhesin (PIA) production. In addition, an increased extracellular DNA release and a higher autolysis rate of SE1457 was detected after nicotine treatment, which was consistent with the increased ratio of dead cells in nicotine-treated SE1457 biofilm observed with confocal laser-scanning microscopy. Furthermore, the effect of nicotine on several autolysis-related and biofilm-related gene knockout mutants of SE1457 was tested. It showed that in ΔsaeRS, ΔlytSR, and ΔsceD, nicotine induced increase in biofilm formation was similar to that in SE1457; but in ΔarlRS, ΔatlE, and ΔicaC, the effect was obviously impaired. Consistently, the increase of the bacterial autolysis rate in ΔarlRS and ΔatlE induced by nicotine was not as significant as that in SE1457. Meanwhile, the growth inhibition of nicotine on SE1457 was observed, and it was much less on ΔarlRS and restored by the arlRS complementation. The arlRS transcription in SE1457 was inhibited by nicotine during cultivation as indicated by a promoter reporter assay using green fluoresent protein. Taken together, our study indicates that nicotine improves S. epidermidis biofilm formation by promoting its initial attachment and intercellular accumulation; the arlRS, atlE, and ica genes mediating bacterial autolysis and PIA production play an important role in this process.},
}
@article {pmid30419487,
year = {2018},
author = {Zeng, Y and Nikitkova, A and Abdelsalam, H and Li, J and Xiao, J},
title = {Activity of quercetin and kaemferol against Streptococcus mutans biofilm.},
journal = {Archives of oral biology},
volume = {98},
number = {},
pages = {9-16},
doi = {10.1016/j.archoralbio.2018.11.005},
pmid = {30419487},
issn = {1879-1506},
abstract = {OBJECTIVE: Nidus Vespae (NV) is the honeycomb of Polistes Olivaceous, P. Japonicus Saussure, and Parapolybiavaria Fabricius. Previously, we have shown the extract and chemical fractions from NV demonstrated remarkable capacities of inhibiting the acid production of oral bacteria at sub-minimum inhibitory concentration (MIC) concentrations. In searching the most potent anti-caries compounds in NV, we further separated the NV Chl/MeOH fraction and obtained two purified compounds: quercetin and kaemferol. The objective of this study was to assess the effectiveness of quercetin and kaemferol against S. mutans biofilm formation.<br><br>METHODS: The MIC, minimum biofilm inhibition concentration (MBIC50) and minimum biofilm reduction concentration (MBRC50) against Streptococcus mutans were examined for NV-derived of quercetin and kaemferol. The effectiveness of inhibiting S. mutans biofilm formation was further examined using in vitro biofilm model.<br><br>RESULTS: Both quercetin and kaemferol compounds demonstrated anti-biofilm activities when compared to the negative control. They are capable of reducing biofilm dry-weight, total protein, viable cells measured by colony forming unit (CFU), insoluble and soluble glucans formation. The in situ culture pH was less acidic when the biofilms were treated by quercetin and kaemferol. The quercetin and kaemferol demonstrated comparable capability of S. mutans killing in biofilms, compared to chlorhexidine.<br><br>CONCLUSIONS: The results of this study showed inhibitory activity of quercetin and kaemferol against S. mutans biofilms, suggesting that quercetin and kaemferol might be considered as alternative anti-caries agents in searching novel anti-caries therapeutics.},
}
@article {pmid30418277,
year = {2018},
author = {Pilz, M and Staats, K and Tobudic, S and Assadian, O and Presterl, E and Windhager, R and Holinka, J},
title = {Zirconium Nitride Coating Reduced Staphylococcus epidermidis Biofilm Formation on Orthopaedic Implant Surfaces: An In Vitro Study.},
journal = {Clinical orthopaedics and related research},
volume = {},
number = {},
pages = {},
doi = {10.1097/CORR.0000000000000568},
pmid = {30418277},
issn = {1528-1132},
abstract = {BACKGROUND: One of the most commonly identified pathogens responsible for orthopaedic implant infection is Staphylococcus epidermidis, which can form biofilms on surfaces. Currently, orthopaedic implants made of various surface materials are available, each with features influencing osseointegration, biocompatibility, and adherence of bacteria to the surface, which is the first step in biofilm formation. The aim of this experimental study was to investigate the effect of a high tribologic-resistant 2.5-µm zirconium nitride top coat on an antiallergic multilayer ceramic-covered cobalt-chromium-molybdenum surface on the formation of S. epidermidis biofilm compared with other commonly used smooth and rough orthopaedic implant surface materials.<br><br>QUESTIONS/PURPOSES: (1) When evaluating the surfaces of a cobalt-chromium-molybdenum (CoCrMo) alloy with a zirconium (Zr) nitride coating, a CoCrMo alloy without a coating, titanium alloy, a titanium alloy with a corundum-blasted rough surface, and stainless steel with a corundum-blasted rough surface, does a Zr coating reduce the number of colony-forming units of S. epidermidis in an in vitro setting? (2) Is there quantitatively less biofilm surface area on Zr-coated surfaces than on the other surfaces tested in this in vitro model?<br><br>METHODS: To determine bacterial adhesion, five different experimental implant surface discs were incubated separately with one of 31 different S. epidermidis strains each and subsequently sonicated. Twenty test strains were obtained from orthopaedic patients undergoing emergency hip prosthesis surgeries or revision of implant infection and 10 further strains were obtained from the skin of healthy individuals. Additionally, one reference strain, S. epidermidis DSM 3269, was tested. After serial dilutions, the number of bacteria was counted and expressed as colony-forming units (CFUs)/mL. For biofilm detection, discs were stained with 0.1% Safranin-O for 15 minutes, photographed, and analyzed with computer imaging software.<br><br>RESULTS: The lowest bacterial count was found in the CoCrMo + Zr surface disc (6.6 x 10 CFU/mL ± 4.6 x 10 SD) followed by the CoCrMo surface (1.1 x 10 CFU/mL ± 1.9 x 10 SD), the titanium surface (1.36 x 10 CFU/mL ± 1.8 x 10 SD), the rough stainless steel surface (2.65 x 10 CFU/mL ± 3.8 x 10 SD), and the rough titanium surface (2.1 x 10 CFU/mL ± 3.0 x 10 SD). The mean CFU count was lower for CoCrMo + Zr discs compared with the rough stainless steel surface (mean difference: 2.0 x 10, p = 0.021), the rough titanium alloy surface (mean difference: 1.4 x 10, p = 0.002), and the smooth titanium surface (mean difference: 7.0 x 10, p = 0.016). The results of biofilm formation quantification show that the mean covered area of the surface of the CoCrMo + Zr discs was 19% (± 16 SD), which was lower than CoCrMo surfaces (35% ± 23 SD), titanium alloy surface (46% ± 20 SD), rough titanium alloy surface (66% ± 23 SD), and rough stainless steel surface (58% ± 18 SD).<br><br>CONCLUSIONS: These results demonstrate that a multilayer, ceramic-covered, CoCrMo surface with a 2.5-µm zirconium nitride top coat showed less S. epidermidis biofilm formation compared with other surface materials used for orthopaedic implants.<br><br>CLINICAL RELEVANCE: CoCrMo with a 2.5-µm zirconium nitride top coat seems to be a promising surface modification technology able to reduce bacterial attachment on the surface of an implant and, hence, may further prevent implant infection with S. epidermidis biofilm formation.},
}
@article {pmid30417874,
year = {2018},
author = {Jin, X and Riedel-Kruse, IH},
title = {High-resolution Patterned Biofilm Deposition Using pDawn-Ag43.},
journal = {Journal of visualized experiments : JoVE},
volume = {},
number = {140},
pages = {},
doi = {10.3791/58625},
pmid = {30417874},
issn = {1940-087X},
abstract = {Spatial structure and patterning play an important role in bacterial biofilms. Here we demonstrate an accessible method for culturing E. coli biofilms into arbitrary spatial patterns at high spatial resolution. The technique uses a genetically encoded optogenetic construct-pDawn-Ag43-that couples biofilm formation in E. coli to optical stimulation by blue light. We detail the process for transforming E. coli with pDawn-Ag43, preparing the required optical set-up, and the protocol for culturing patterned biofilms using pDawn-Ag43 bacteria. Using this protocol, biofilms with a spatial resolution below 25 μm can be patterned on various surfaces and environments, including enclosed chambers, without requiring microfabrication, clean-room facilities, or surface pretreatment. The technique is convenient and appropriate for use in applications that investigate the effect of biofilm structure, providing tunable control over biofilm patterning. More broadly, it also has potential applications in biomaterials, education, and bio-art.},
}
@article {pmid30417215,
year = {2018},
author = {Butini, ME and Gonzalez Moreno, M and Czuban, M and Koliszak, A and Tkhilaishvili, T and Trampuz, A and Di Luca, M},
title = {Real-Time Antimicrobial Susceptibility Assay of Planktonic and Biofilm Bacteria by Isothermal Microcalorimetry.},
journal = {Advances in experimental medicine and biology},
volume = {},
number = {},
pages = {},
doi = {10.1007/5584_2018_291},
pmid = {30417215},
issn = {0065-2598},
abstract = {Most antimicrobials currently used in the clinical practice are tested as growth inhibitors against free-floating microorganisms in a liquid suspension, rather than against sessile cells constituting biofilms. Hence, reliable, fast, and reproducible methods for assessing biofilm susceptibility to antimicrobials are strongly needed. Isothermal microcalorimetry (IMC) is a nondestructive sensitive technique that allows for the real-time monitoring of microbial viability in the presence or absence of antimicrobial compounds. Therefore, the efficacy of specific antimicrobials, alone or in combination, may be promptly validated supporting the development of new drugs and avoiding the administration of ineffective therapies. Furthermore, the susceptibility of both planktonic and biofilm cells to antimicrobials can be conveniently assessed without the need for elaborated staining procedures and under nontoxic working conditions. Quantitative data regarding the antimicrobial effect against different strains might be collected by monitoring the microbial cell replication, and, more importantly, a dose-dependent activity can be efficiently detected by measuring the delay and decrease in the heat flow peak of the treated samples. A limitation of IMC for anti-biofilm susceptibility test is the inability to directly quantify the non-replicating cells in the biofilm or the total biomass. However, as IMC is a nondestructive method, the samples can be also analyzed by using different techniques, acquiring more information complementary to calorimetric data. IMC finds application also for the investigation of antibiotic eluting kinetics from different biomaterials, as well as for studying bacteriophages activity against planktonic and biofilm bacteria. Thus, the wide applicability of this ultra-sensitive and automated technique provides a further advance in the field of clinical microbiology and biomedical sciences.},
}
@article {pmid30414418,
year = {2018},
author = {da Silva, PM and Baldry, M and Peng, P and de Oliveira Silva, JN and Soares, T and Brayner, FA and Alves, LC and Feitosa, APS and Paiva, PMG and Ingmer, H and Napoleão, TH},
title = {Punica granatum sarcotesta lectin (PgTeL) impairs growth, structure, viability, aggregation, and biofilm formation ability of Staphylococcus aureus clinical isolates.},
journal = {International journal of biological macromolecules},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijbiomac.2018.11.030},
pmid = {30414418},
issn = {1879-0003},
abstract = {In this work, we evaluated the ability of Punica granatum sarcotesta lectin (PgTeL) to impair the growth and viability of the Staphylococcus aureus clinical isolates 8325-4 (non-resistant) and LAC USA300 (MRSA strain). The effects of this lectin on aggregating, hemolytic activity, biofilm-forming ability, and expression of virulence genes (hla, rnaIII, and spa) were also investigated. PgTeL showed antibacterial activity against 8325-4 and LAC USA300 strains by interfering with both the growth (MIC50 of 6.25 and 12.5 μg/mL, respectively) and survival (MBC values of 25.0 and 50.0 μg/mL). Culture growth started only at the ninth (8325-4) and tenth (LAC USA300) hour in the presence of PgTeL at MIC50, while growth was detected since the first hour in the control. The lectin caused markedly altered cell morphology in both the strains. Although, at the MIC50, PgTeL caused structural alterations, most cells were still viable, while at the MBC it promoted cell injury and death. PgTeL showed anti-aggregation effect and exhibited antibiofilm activity against both the isolates. However, the lectin did not interfere with the hemolytic activity of LAC USA300 and with the expression of hla, rnaIII, and spa genes. In conclusion, PgTeL is a lectin with multiple inhibitory effects on S. aureus clinical isolates.},
}
@article {pmid30412313,
year = {2018},
author = {Stenhagen, ISR and Rukke, HV and Dragland, IS and Kopperud, HM},
title = {Effect of methacrylated chitosan incorporated in experimental composite and adhesive on mechanical properties and biofilm formation.},
journal = {European journal of oral sciences},
volume = {},
number = {},
pages = {},
doi = {10.1111/eos.12584},
pmid = {30412313},
issn = {1600-0722},
abstract = {The lifespan of a resin-based restoration is limited, with the main reason for failure being secondary caries. Biofilm formation at the tooth-material interface is a necessary etiological agent for caries development. Dental materials with antimicrobial properties may reduce formation of biofilm and thus increase the longevity of restorations. This study aimed to investigate the effect of methacrylated chitosan (CH-MA), incorporated into the polymeric network of an experimental dental composite and adhesive, on biofilm growth of Streptococcus mutans and to assess the mechanical properties of the modified materials. The methacrylation of low-molecular-weight chitosan was achieved and biofilm studies confirmed the antibacterial effect of the modified polymer in solution. Methacrylated chitosan was incorporated into an experimental composite and adhesive, and the modified materials reduced the formation of S. mutans biofilm. The incorporation of CH-MA did not alter the bond strength of the adhesives. However, the amount of CH-MA in composite that is required to elicit an antibacterial response challenges the mechanical properties of the material. The hardness and flexural strength of the composite decreased with increasing amounts of CH-MA. However, flexural strength values still met the requirement in the ISO standard.},
}
@article {pmid30411687,
year = {2018},
author = {Zayed, MF and Ibrahim, SRM and Habib, EE and Hassan, MH and Ahmed, S and Rateb, HS},
title = {Design, synthesis, antimicrobial and anti-biofilm evaluation, and molecular docking of new substituted fluoroquinazolinones.},
journal = {Medicinal chemistry (Shariqah (United Arab Emirates))},
volume = {},
number = {},
pages = {},
doi = {10.2174/1573406414666181109092944},
pmid = {30411687},
issn = {1875-6638},
abstract = {BACKGROUND: Quinazolines and quinazolinones derivatives are well known for their important range of therapeutic activities.<br><br>OBJECTIVE: Synthesis of some derivatives of substituted fluoroquinazolinones based on structure-based design and evaluation of their antibacterial, antifungal, and anti-biofilm activities.<br><br>METHOD: Compounds were chemically synthesized by conventional methods. Structures were established on the basis of spectral and elemental analyses. Antimicrobial potential was tested against various microorganisms using the agar disc-diffusion method. MIC and MBC as well as anti-biofilm activity for the highly active compounds were assessed. Moreover, the computational studies were performed using Auto dock free software package (version 4.0) to explain the predicted mode of binding.<br><br>RESULT: All derivatives (5-8), (10a-g), and (A-H) were biologically tested and showed significant antimicrobial activity comparable to the reference compounds. Compounds 10b, 10c, and 10d had a good MIC and MBC against Gram-positive bacteria, whereas 10b and 10d showed significant MIC and MBC against Gram-negative bacteria. However, compounds E and F exhibited good MIC and MBC against fungi. Compound 10c and 8 exhibited significant anti-biofilm activity towards S. aureus and M. luteus. Molecular docking study revealed a strong binding of these derivatives with their receptor-site and detected their predicted mode of binding.<br><br>CONCLUSION: The synthesized derivatives showed promising antibacterial, antifungal, and anti-biofilm activities. Modeling study explained their binding mode and showed strong binding affinity with their receptor-site. The highly active compounds 5 and 10c could be subjected to future optimization and investigation to be effective antimicrobial agents.},
}
@article {pmid30411288,
year = {2018},
author = {Yan, PF and Yuan, S and Wang, W and Hu, ZH and Mu, Y and Yu, HQ},
title = {Efficiency of sequential UV/H2O2 and biofilm process for the treatment of secondary effluent.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-018-3606-6},
pmid = {30411288},
issn = {1614-7499},
support = {51538012//National Natural Science Foundation of China/ ; 51578205//National Natural Science Foundation of China/ ; 51728801//National Natural Science Foundation of China/ ; },
abstract = {In response to the shortage of water resources, multiple processes have been applied to turn wastewater secondary effluent (SE) into potable water. However, trace organic contaminants (TOrCs) and high concentrations of organic matter contained in SE pose a significant challenge to the reclamation. In this manuscript, combined UV-based and biofilm processes were used to treat the SE spiked with ibuprofen (IBU) and clofibric acid (CA). The efficiency of these sequential treatments was characterized in terms of changes in dissolved organic carbon (DOC), absorbance at 254 nm (A254), fluorescence excitation-emission matrix (FEEM), the concentration of IBU and CA, and molecular weight of SE. Parallel factor (PARAFAC) was applied as the analysis method for FEEM of the samples and two fluorescent components were successfully identified: humic-like substances (C1) and protein-like matter (C2). Large reductions in A254, C1, C2, IBU, and CA were observed during the UV-based processes, especially with the addition of H2O2. Nearly 50% of A254, 80% of the component C1 were decreased and almost complete removal of the component C2 and TOrCs was achieved by UV/2.0 mM H2O2 after 90-min treatment. During the oxidation processes, the formation of lower molecular weight (LMW) compounds was detected, and the biodegradability of the organic matters was greatly increased. Although no significant DOC reduction was obtained in UV-based processes, an obvious further DOC reduction (30~60%) was achieved by biofilm treatment following UV-based processes, especially after UV/H2O2 treatments. In the meantime, large amounts of LMW were removed in the biofilm treatment process. This manuscript provides an effective advanced treatment of SE for the removal of DOC and TOrCs, facilitating the wastewater reclamation.},
}
@article {pmid30410871,
year = {2018},
author = {Husain, FM and Ahmad, I and Khan, FI and Al-Shabib, NA and Baig, MH and Hussain, A and Rehman, MT and Alajmi, MF and Lobb, KA},
title = {Seed Extract of Psoralea corylifolia and Its Constituent Bakuchiol Impairs AHL-Based Quorum Sensing and Biofilm Formation in Food- and Human-Related Pathogens.},
journal = {Frontiers in cellular and infection microbiology},
volume = {8},
number = {},
pages = {351},
doi = {10.3389/fcimb.2018.00351},
pmid = {30410871},
issn = {2235-2988},
abstract = {The emergence of multi-drug resistance in pathogenic bacteria in clinical settings as well as food-borne infections has become a serious health concern. The problem of drug resistance necessitates the need for alternative novel therapeutic strategies to combat this menace. One such approach is targeting the quorum-sensing (QS) controlled virulence and biofilm formation. In this study, we first screened different fractions of Psoralea corylifolia (seed) for their anti-QS property in the Chromobacterium violaceum 12472 strain. The methanol fraction was found to be the most active fraction and was selected for further bioassays. At sub-inhibitory concentrations, the P. corylifolia methanol fraction (PCMF) reduced QS-regulated virulence functions in C. violaceum CVO26 (violacein); Pseudomonas aeruginosa (elastase, protease, pyocyanin, chitinase, exopolysaccharides (EPS), and swarming motility), A. hydrophila (protease, EPS), and Serratia marcescens (prodigiosin). Biofilm formation in all the test pathogens was reduced significantly (p ≤ 0.005) in a concentration-dependent manner. The β-galactosidase assay showed that the PCMF at 1,000 μg/ml downregulated las-controlled transcription in PAO1. In vivo studies with C. elegans demonstrated increased survival of the nematodes after treatment with the PCMF. Bakuchiol, a phytoconstituent of the extract, demonstrated significant inhibition of QS-regulated violacein production in C. violaceum and impaired biofilm formation in the test pathogens. The molecular docking results suggested that bakuchiol efficiently binds to the active pockets of LasR and RhlR, and the complexes were stabilized by several hydrophobic interactions. Additionally, the molecular dynamics simulation of LasR, LasR-bakuchiol, RhlR, and RhlR-bakuchiol complexes for 50 ns revealed that the binding of bakuchiol to LasR and RhlR was fairly stable. The study highlights the anti-infective potential of the PCMF and bakuchiol instead of bactericidal or bacteriostatic action, as the extract targets QS-controlled virulence and the biofilm.},
}
@article {pmid30408663,
year = {2018},
author = {Liao, K and Bai, Y and Huo, Y and Jian, Z and Hu, W and Zhao, C and Qu, J},
title = {Use of convertible flow cells to simulate the impacts of anthropogenic activities on river biofilm bacterial communities.},
journal = {The Science of the total environment},
volume = {653},
number = {},
pages = {148-156},
doi = {10.1016/j.scitotenv.2018.10.363},
pmid = {30408663},
issn = {1879-1026},
abstract = {Bacterial attachment to surfaces and the development of biofilms are crucial processes during the self-purification of polluted rivers. Biofilm bacterial communities also are a potential indicator of the human impact on an aquatic system. Here, we used indoor reactors with 7.7 cm3 transparent convertible flow cells to observe the formation of biofilms in river water from different land-use areas (i.e., an undisturbed mountainous area, a wastewater-discharge urban area, and a pesticide-fertilizer applied agricultural area). We then compared the bacterial biomass, composition, and function among the formed biofilms and explored whether the biofilm bacterial communities formed in polluted river water (urban area) could shift to those formed in unpolluted water (mountainous area) after simulating water-body remediation. After 60 d of indoor biofilm cultivation, the biofilms formed with the three types of influent were markedly different. Anthropogenic activities (e.g., wastewater discharge and pesticide-fertilizer use) facilitated biofilm bacterial production and the metabolic rate and altered the composition and metabolic patterns of the biofilm bacterial communities. After switching from an urban water to mountainous water influent in the same reactor, the biofilm bacterial communities that initially formed in the polluted discharge did not shift to that formed in unpolluted water. This result indicated that even after water remediation, the composition of the river biofilm bacterial community would not recover to a community like that observed under non-polluted conditions. Our study highlights possible issues related to current pollution-remediation routines and emphasizes the importance of sustainable anthropogenic activities within river basins.},
}
@article {pmid30407731,
year = {2018},
author = {Ebersole, JL and Peyyala, R and Gonzalez, OA},
title = {Biofilm Induced Profiles of Immune Response Gene Expression by Oral Epithelial Cells.},
journal = {Molecular oral microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/omi.12251},
pmid = {30407731},
issn = {2041-1014},
abstract = {OBJECTIVE: This study examined the oral epithelial immunotranscriptome response patterns modulated by oral bacterial planktonic or biofilm challenge METHODS: We assessed gene expression patterns when epithelial cells were challenged with a multispecies biofilm composed of S. gordonii, F. nucleatum, and P. gingivalis representing a type of periodontopathic biofilm compared to challenge with the same species of planktonic bacteria RESULTS: Of the 579 human immunology genes, a substantial signal of the epithelial cells was observed to 181 genes. Biofilm challenged stimulated significant elevations compared to planktonic bacteria for IL32, IL8, CD44, B2M, TGFBI, NFKBIA, IL1B, CD59, IL1A, CCL20 representing the top 10 signals comprising 55% of the overall signal for the epithelial cell responses. Levels of PLAU, CD9, IFITM1, PLAUR, CD24, TNFSF10, and IL1RN were all elevated by each of the planktonic bacterial challenge versus the biofilm responses. While the biofilms upregulated 123/579 genes (>2-fold), fewer genes were increased by the planktonic species [36 (S. gordonii), 30 (F. nucleatum), 44 (P. gingivalis)] CONCLUSIONS: A wide array of immune genes were regulated by oral bacterial challenge of epithelial cells that would be linked to the local activity of innate and adaptive immune response components in the gingival tissues. Incorporating bacterial species into a structured biofilm dramatically altered the number and level of genes expressed. Additionally a specific set of genes were significantly decreased with the multispecies biofilms suggesting that some epithelial cell biologic pathways are down-regulated when in contact with this type of pathogenic biofilm. This article is protected by copyright. All rights reserved.},
}
@article {pmid30406882,
year = {2018},
author = {Das, T and Das, MC and Das, A and Bhowmik, S and Sandhu, P and Akhter, Y and Bhattacharjee, S and De, UC},
title = {Modulation of S. aureus and P. aeruginosa biofilm: an in vitro study with new coumarin derivatives.},
journal = {World journal of microbiology &amp; biotechnology},
volume = {34},
number = {11},
pages = {170},
doi = {10.1007/s11274-018-2545-1},
pmid = {30406882},
issn = {1573-0972},
abstract = {Coumarin is an important heterocyclic molecular framework of bioactive molecules against broad spectrum pathological manifestations. In the present study 18 new coumarin derivatives (CDs) were synthesized and characterized for antibiofilm activity against two model bacteria such as Staphylococcus aureus and Pseudomonas aeruginosa. It was observed that all the CDs executed significant effect in moderating activities against both planktonic and biofilm forms of these selected bacteria. Hence, to interpret the underlying probable reason of such antibiofilm effect, in-silico binding study of CDs with biofilm and motility associated proteins of these organisms were performed. All CDs have shown their propensity for occupying the native substrate binding pocket of each protein with moderate to strong binding affinities. One of the CDs such as CAMN1 showed highest binding affinity with these proteins. Interestingly, the findings of in-silico studies coincides the experimental results of antibiofilm and motility affect of CDs against both S. aureus and P. aeruginosa. Moreover, in-silico studies suggested that the antibiofilm activity of test CDs may be due to the interference of biofilm and motility associated proteins of the selected model organisms (PilT from P. aeruginosa and TarK, TarO from S. aureus). The detailed synthesis, characterization, methodology and results of biological screening along with computational studies have been reported. This study could be of greater interest in the context of the development of new anti-bacterial agent in the future.},
}
@article {pmid30406460,
year = {2018},
author = {Ali, SS and Kenawy, ER and Sonbol, FI and Sun, J and Al-Etewy, M and Ali, A and Huizi, L and El-Zawawy, NA},
title = {Pharmaceutical Potential of a Novel Chitosan Derivative Schiff Base with Special Reference to Antibacterial, Anti-Biofilm, Antioxidant, Anti-Inflammatory, Hemocompatibility and Cytotoxic Activities.},
journal = {Pharmaceutical research},
volume = {36},
number = {1},
pages = {5},
doi = {10.1007/s11095-018-2535-x},
pmid = {30406460},
issn = {1573-904X},
support = {NNSF-31772529//National Natural Science Foundation of China/ ; PAPD-4013000011//Priority of Academic Program Development/ ; Egyptian Ministry of Higher Education &amp; Scientific Research (MHESR); Support of Excellent Students Projects (SESP)//Egyptian Ministry of Higher Education &amp; Scientific Research (MHESR); Support of Excellent Students Projects (SESP)/ ; },
abstract = {PURPOSE: Chitosan and its derivatives possess several unique properties relevant in the field of pharmaceutics and medicinal chemistry. This study aimed to evaluate the pharmaceutical performance of an innovative chitosan derivative, methyl acrylate chitosan bearing p-nitrobenzaldehyde (MA*CS*pNBA) Schiff base.<br><br>METHODS: The antibacterial activity of MA*CS*pNBA was tested against multi-drug resistant (MDR) Gram-negative and Gram-positive bacteria using agar-well diffusion method. Anti-biofilm formation was analyzed using a microtitre plate. Antioxidant assays were performed to assess the scavenging activity of MA*CS*pNBA using DPPH, hydrogen peroxide, superoxide together with its reducing power activity. Anti-inflammatory activity was evaluated by albumin denaturation, membrane stabilization, and proteinase inhibition methods. MA*CS*pNBA was tested for its hemolytic efficiency on human erythrocytes. Cytotoxicity of MA*CS*pNBA was evaluated by MTT assay.<br><br>RESULTS: MA*CS*pNBA showed a significant performance as an antibacterial candidate against MDR bacteria, anti-biofilm, antioxidant and anti-inflammatory biomaterial, evidencing hemocompatibility and no cytotoxicity. It exhibited a significant negative correlation with biofilm formation by the MDR-PA-09 strain. Biological activities were found to be significantly concentration-dependent.<br><br>CONCLUSIONS: the newly chitosan derivative MA*CS*pNBA showed to be promising for pharmaceutical applications, expanding the treatment ways toward skin burn infections since it allied excellent antibacterial, anti-biofilm, antioxidant, anti-inflammatory, hemocompatibility and absence of cytotoxic activities.},
}
@article {pmid30406042,
year = {2018},
author = {Bhandari, V and Chakraborty, S and Brahma, U and Sharma, P},
title = {Identification of Anti-staphylococcal and Anti-biofilm Compounds by Repurposing the Medicines for Malaria Venture Pathogen Box.},
journal = {Frontiers in cellular and infection microbiology},
volume = {8},
number = {},
pages = {365},
doi = {10.3389/fcimb.2018.00365},
pmid = {30406042},
issn = {2235-2988},
abstract = {There has been an alarming increase in infections caused by antimicrobial-resistant pathogens. These infections are responsible for more than half a million deaths globally each year. Staphylococcus aureus is one of the deadliest bacterial pathogen responsible for nosocomial and community acquired infections. The open-access Pathogen Box (PBox) provides a potential platform to identify new treatment options against antibiotic-resistant bacteria by repurposing it. In this study, we have screened the PBox library comprised of ~400 compounds to identify novel anti-staphylococcal compounds. in vitro antimicrobial screening using S. aureus isolates, ATCC 29213 (methicillin-sensitive) and ATCC 700699 (methicillin-resistant) revealed 13 compounds which showed highly potent antibacterial activity against both planktonic and biofilm state. The 13 compounds were not found cytotoxic to mouse macrophage cell line, RAW264.7. Out of the 13 compounds, only MMV687251 and MMV676477 revealed structural similarity with vancomycin by comparing their atomic pair fingerprints using Tanimoto coefficient method. The structural similarities may indicate similar mode of action like vancomycin for the two compounds. Our result showed that PBox compounds offer a promising lead for the development of new anti-staphylococcal treatment options.},
}
@article {pmid30405717,
year = {2018},
author = {Marak, MB and Dhanashree, B},
title = {Antifungal Susceptibility and Biofilm Production of Candida spp. Isolated from Clinical Samples.},
journal = {International journal of microbiology},
volume = {2018},
number = {},
pages = {7495218},
doi = {10.1155/2018/7495218},
pmid = {30405717},
issn = {1687-918X},
abstract = {Objective: The study aims to speciate clinical Candida isolates and detect their biofilm-forming ability and antifungal resistance.<br><br>Methods: All the Candida spp. isolated from different clinical samples like pus, urine, blood, and body fluid were included in the study. Biofilm production was tested by the microtiter plate method. Antifungal susceptibility was studied by the disk diffusion method. Patient's demographic details such as age, sex, and clinical information were collected. Presence of other risk factors such as diabetes mellitus, history of antibiotic use, and any urinary tract instrumentations was also recorded.<br><br>Results: Among 90 Candida species isolated, most predominant species was found to be C. albicans (45.5%) followed by C. tropicalis (28.88%), C. krusei (20%), C. glabrata (3.33%), and C. parapsilosis (2.22%). Candida spp. were isolated from urine (43%), BAL/sputum (18.88%), high vaginal swab (8.88%), suction tips (7.77%), blood and wound swabs (6.66%), pus (3.33%), bile aspirate (2.22%), and deep tissue (1.11%). A larger number of females were affected than males, and the age group of 51 to 60 years was more susceptible to candidiasis. A higher number of C. albicans isolates produced biofilm followed by C. parapsilosis, C. tropicalis, and C. krusei. However, C. glabrata showed no biofilm production in our study. All Candida isolates were 100% sensitive to amphotericin B. Voriconazole was the next effective drug with 81.11% susceptibility. 24.44% of strains were resistant to fluconazole.<br><br>Conclusion: Speciation of Candida isolates, detection of ability to form the biofilm, and monitoring of antifungal susceptibility testing are necessary for appropriate treatment.},
}
@article {pmid30405559,
year = {2018},
author = {Li, T and Sharp, CE and Ataeian, M and Strous, M and de Beer, D},
title = {Role of Extracellular Carbonic Anhydrase in Dissolved Inorganic Carbon Uptake in Alkaliphilic Phototrophic Biofilm.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {2490},
doi = {10.3389/fmicb.2018.02490},
pmid = {30405559},
issn = {1664-302X},
abstract = {Alkaline Soda Lakes are extremely productive ecosystems, due to their high dissolved inorganic carbon (DIC) concentrations. Here, we studied the dynamics of the carbonate system, in particular, the role of extracellular carbonic anhydrase (eCA) of an alkaliphilic phototrophic biofilm composed of bacteria enriched from soda lake benthic mats. By using measurements with microsensors and membrane inlet mass spectrometry, combined with mathematical modeling, we show how eCA controls DIC uptake. In our experiments, the activity of eCA varied four-fold, and was controlled by the bicarbonate concentration during growth: a higher bicarbonate concentration led to lower eCA activity. Inhibition of eCA decreased both the net and the gross photosynthetic productivities of the investigated biofilms. After eCA inhibition, the efflux of carbon dioxide (CO2) from the biofilms increased two- to four-fold. This could be explained by the conversion of CO2, leaking from cyanobacterial cells, by eCA, to bicarbonate. Bicarbonate is then taken up again by the cyanobacteria. In suspensions, eCA reduced the CO2 leakage to the bulk medium from 90 to 50%. In biofilms cultivated at low bicarbonate concentration (~0.13 mM), the oxygen production was reduced by a similar ratio upon eCA inhibition. The role of eCA in intact biofilms was much less significant compared to biomass suspensions, as CO2 loss to the medium is reduced due to mass transfer resistance.},
}
@article {pmid30405082,
year = {2018},
author = {Chong, PP and Chin, VK and Wong, WF and Madhavan, P and Yong, VC and Looi, CY},
title = {Transcriptomic and Genomic Approaches for Unravelling Candida albicans Biofilm Formation and Drug Resistance-An Update.},
journal = {Genes},
volume = {9},
number = {11},
pages = {},
doi = {10.3390/genes9110540},
pmid = {30405082},
issn = {2073-4425},
abstract = {Candida albicans is an opportunistic fungal pathogen, which causes a plethora of superficial, as well as invasive, infections in humans. The ability of this fungus in switching from commensalism to active infection is attributed to its many virulence traits. Biofilm formation is a key process, which allows the fungus to adhere to and proliferate on medically implanted devices as well as host tissue and cause serious life-threatening infections. Biofilms are complex communities of filamentous and yeast cells surrounded by an extracellular matrix that confers an enhanced degree of resistance to antifungal drugs. Moreover, the extensive plasticity of the C. albicans genome has given this versatile fungus the added advantage of microevolution and adaptation to thrive within the unique environmental niches within the host. To combat these challenges in dealing with C. albicans infections, it is imperative that we target specifically the molecular pathways involved in biofilm formation as well as drug resistance. With the advent of the -omics era and whole genome sequencing platforms, novel pathways and genes involved in the pathogenesis of the fungus have been unraveled. Researchers have used a myriad of strategies including transcriptome analysis for C. albicans cells grown in different environments, whole genome sequencing of different strains, functional genomics approaches to identify critical regulatory genes, as well as comparative genomics analysis between C. albicans and its closely related, much less virulent relative, C. dubliniensis, in the quest to increase our understanding of the mechanisms underlying the success of C. albicans as a major fungal pathogen. This review attempts to summarize the most recent advancements in the field of biofilm and antifungal resistance research and offers suggestions for future directions in therapeutics development.},
}
@article {pmid30404971,
year = {2018},
author = {Grillo-Puertas, M and Delaporte-Quintana, P and Pedraza, RO and Rapisarda, VA},
title = {Intracellular Polyphosphate Levels in Gluconacetobacter diazotrophicus Affect Tolerance to Abiotic Stressors and Biofilm Formation.},
journal = {Microbes and environments},
volume = {},
number = {},
pages = {},
doi = {10.1264/jsme2.ME18044},
pmid = {30404971},
issn = {1347-4405},
abstract = {Gluconacetobacter diazotrophicus is a plant growth-promoting bacterium that is used as a bioinoculant. Phosphate (Pi) modulates intracellular polyphosphate (polyP) levels in Escherichia coli, affecting cellular fitness and biofilm formation capacity. It currently remains unclear whether environmental Pi modulates polyP levels in G. diazotrophicus to enhance fitness in view of its technological applications. In high Pi media, cells accumulated polyP and degraded it, thereby improving survival, tolerance to environmental stressors, biofilm formation capacity on abiotic and biotic surfaces, and competence as a growth promoter of strawberry plants. The present results support the importance of Pi and intracellular polyP as signals involved in the survival of G. diazotrophicus.},
}
@article {pmid30404183,
year = {2018},
author = {Kot, B and Sytykiewicz, H and Sprawka, I},
title = {Expression of the Biofilm-Associated Genes in Methicillin-Resistant Staphylococcus aureus in Biofilm and Planktonic Conditions.},
journal = {International journal of molecular sciences},
volume = {19},
number = {11},
pages = {},
doi = {10.3390/ijms19113487},
pmid = {30404183},
issn = {1422-0067},
abstract = {The role of genes that are essential for development of Staphylococcus aureus biofilm during infection is not fully known. mRNA from two methicillin-resistant S. aureus strains that formed weak and strong biofilm on polystyrene plates were isolated at five time points from cells grown in biofilm and planktonic culture. Quantitative real-time PCR analysis showed that the expression levels of investigated genes under biofilm conditions were significantly higher than under planktonic conditions. The expression levels of the gene encoding elastin binding protein (ebps) and laminin binding protein (eno) were significantly increased in biofilm at 3 h, both in strongly and weakly adhering strain. The peak expression of fib gene encoding fibrinogen binding protein was found at 6 and 8 h in the case of strongly and weakly adhering strain, respectively. The expression of icaA and icaD genes in both strains was significantly higher under biofilm conditions when comparing to planktonic cells during 12 h. The expression level of the genes encoding binding proteins and the glucosamine polymer polysaccharide intercellular adhesin (PIA) slowly decreased after 24 h. Finally, we found that the expression levels of genes encoding binding factors in weakly adhering strain were significantly lower than in strongly adhering strain.},
}
@article {pmid30403745,
year = {2018},
author = {Pederson, DB and Dong, Y and Blue, LB and Smith, SV and Cao, M},
title = {Water-soluble cranberry extract inhibits Vibrio cholerae biofilm formation possibly through modulating the second messenger 3', 5' - Cyclic diguanylate level.},
journal = {PloS one},
volume = {13},
number = {11},
pages = {e0207056},
doi = {10.1371/journal.pone.0207056},
pmid = {30403745},
issn = {1932-6203},
abstract = {Quorum sensing (QS) and nucleotide-based second messengers are vital signaling systems that regulate bacterial physiology in response to changing environments. Disrupting bacterial signal transduction is a promising direction to combat infectious diseases, and QS and the second messengers are undoubtedly potential targets. In Vibrio cholerae, both QS and the second messenger 3', 5'-cyclic diguanylate (c-di-GMP) play a central role in controlling motility, motile-to-sessile life transition, and virulence. In this study, we found that water-soluble extract from the North American cranberry could significantly inhibit V. cholerae biofilm formation during the development/maturation stage by reducing the biofilm matrix production and secretion. The anti-biofilm effect by water-soluble cranberry extract was possibly through modulating the intracellular c-di-GMP level and was independent of QS and the QS master regulator HapR. Our results suggest an opportunity to explore more functional foods to fight stubborn infections through interference with the bacterial signaling systems.},
}
@article {pmid30401769,
year = {2018},
author = {Chew, SC and Yam, JKH and Matysik, A and Seng, ZJ and Klebensberger, J and Givskov, M and Doyle, P and Rice, SA and Yang, L and Kjelleberg, S},
title = {Matrix Polysaccharides and SiaD Diguanylate Cyclase Alter Community Structure and Competitiveness of Pseudomonas aeruginosa during Dual-Species Biofilm Development with Staphylococcus aureus.},
journal = {mBio},
volume = {9},
number = {6},
pages = {},
doi = {10.1128/mBio.00585-18},
pmid = {30401769},
issn = {2150-7511},
abstract = {Mixed-species biofilms display a number of emergent properties, including enhanced antimicrobial tolerance and communal metabolism. These properties may depend on interspecies relationships and the structure of the biofilm. However, the contribution of specific matrix components to emergent properties of mixed-species biofilms remains poorly understood. Using a dual-species biofilm community formed by the opportunistic pathogens Pseudomonas aeruginosa and Staphylococcus aureus, we found that whilst neither Pel nor Psl polysaccharides, produced by P. aeruginosa, affect relative species abundance in mature P. aeruginosa and S. aureus biofilms, Psl production is associated with increased P. aeruginosa abundance and reduced S. aureus aggregation in the early stages of biofilm formation. Our data suggest that the competitive effect of Psl is not associated with its structural role in cross-linking the matrix and adhering to P. aeruginosa cells but is instead mediated through the activation of the diguanylate cyclase SiaD. This regulatory control was also found to be independent of the siderophore pyoverdine and Pseudomonas quinolone signal, which have previously been proposed to reduce S. aureus viability by inducing lactic acid fermentation-based growth. In contrast to the effect mediated by Psl, Pel reduced the effective crosslinking of the biofilm matrix and facilitated superdiffusivity in microcolony regions. These changes in matrix cross-linking enhance biofilm surface spreading and expansion of microcolonies in the later stages of biofilm development, improving overall dual-species biofilm growth and increasing biovolume severalfold. Thus, the biofilm matrix and regulators associated with matrix production play essential roles in mixed-species biofilm interactions.IMPORTANCE Bacteria in natural and engineered environments form biofilms that include many different species. Microorganisms rely on a number of different strategies to manage social interactions with other species and to access resources, build biofilm consortia, and optimize growth. For example, Pseudomonasaeruginosa and Staphylococcus aureus are biofilm-forming bacteria that coinfect the lungs of cystic fibrosis patients and diabetic and chronic wounds. P. aeruginosa is known to antagonize S. aureus growth. However, many of the factors responsible for mixed-species interactions and outcomes such as infections are poorly understood. Biofilm bacteria are encased in a self-produced extracellular matrix that facilitates interspecies behavior and biofilm development. In this study, we examined the poorly understood roles of the major matrix biopolymers and their regulators in mixed-species biofilm interactions and development.},
}
@article {pmid30400188,
year = {2018},
author = {Melo, MAS and Weir, MD and Passos, VF and Rolim, JPM and Lynch, CD and Rodrigues, LKA and Xu, HHK},
title = {Human In Situ Study of the effect of Bis(2-Methacryloyloxyethyl) Dimethylammonium Bromide Immobilized in Dental Composite on Controlling Mature Cariogenic Biofilm.},
journal = {International journal of molecular sciences},
volume = {19},
number = {11},
pages = {},
doi = {10.3390/ijms19113443},
pmid = {30400188},
issn = {1422-0067},
support = {141791/2010-1//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; },
abstract = {Cariogenic oral biofilms cause recurrent dental caries around composite restorations, resulting in unprosperous oral health and expensive restorative treatment. Quaternary ammonium monomers that can be copolymerized with dental resin systems have been explored for the modulation of dental plaque biofilm growth over dental composite surfaces. Here, for the first time, we investigated the effect of bis(2-methacryloyloxyethyl) dimethylammonium bromide (QADM) on human overlying mature oral biofilms grown intra-orally in human participants for 7⁻14 days. Seventeen volunteers wore palatal devices containing composite specimens containing 10% by mass of QADM or a control composite without QADM. After 7 and 14 days, the adherent biofilms were collected to determine bacterial counts via colony-forming unit (CFU) counts. Biofilm viability, chronological changes, and percentage coverage were also determined through live/dead staining. QADM composites caused a significant inhibition of Streptococcus mutans biofilm formation for up to seven days. No difference in the CFU values were found for the 14-day period. Our findings suggest that: (1) QADM composites were successful in inhibiting 1⁻3-day biofilms in the oral environment in vivo; (2) QADM significantly reduced the portion of the S. mutans group; and (3) stronger antibiofilm activity is required for the control of mature long-term cariogenic biofilms. Contact-killing strategies using dental materials aimed at preventing or at least reducing high numbers of cariogenic bacteria seem to be a promising approach in patients at high risk of the recurrence of dental caries around composites.},
}
@article {pmid30398942,
year = {2018},
author = {},
title = {Skin Integrity and Infection Prevention Las Vegas: the science of biofilm, a multifaceted challenge to healing.},
journal = {Journal of wound care},
volume = {27},
number = {11},
pages = {756-757},
doi = {10.12968/jowc.2018.27.11.756},
pmid = {30398942},
issn = {0969-0700},
abstract = {At the 4th International Skin Integrity and Infection Prevention conference, hosted by the Journal of Wound Care and the University of Huddersfield, in Las Vegas, one of the main themes was the control and resolution of biofilm. A series of reports will describe the key points of four sponsored symposia at the event. The first of these concentrates on the role of biofilm in chronic wounds and new therapies to aid the healing of these wounds by disrupting biofilm.},
}
@article {pmid30398940,
year = {2018},
author = {},
title = {Skin Integrity and Infection Prevention Las Vegas: don't bust on biofilm, bet on dHACM.},
journal = {Journal of wound care},
volume = {27},
number = {11},
pages = {764-766},
doi = {10.12968/jowc.2018.27.11.764},
pmid = {30398940},
issn = {0969-0700},
abstract = {The 4th International Skin Integrity and Infection Prevention conference, hosted by the Journal of Wound Care and the University of Huddersfield, was held earlier this year in Las Vegas. A key theme was the impact of biofilm on wound healing. In the second of our sponsored symposia reports, the manner in which delayed healing can be reversed through effective biofilm management, and the introduction of regulatory proteins found in dehydrated human amnion chorion membrane allograft were explained.},
}
@article {pmid30397766,
year = {2018},
author = {Gu, Y and Xu, Y and Xu, J and Yu, X and Huang, X and Liu, G and Liu, X},
title = {Identification of novel bacteriophage vB_EcoP-EG1 with lytic activity against planktonic and biofilm forms of uropathogenic Escherichia coli.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-018-9471-x},
pmid = {30397766},
issn = {1432-0614},
support = {81501797//National Natural Science Foundation of China/ ; BK20151558//Natural Science Foundation of Jiangsu Province/ ; },
abstract = {Urinary tract infections are one of the most common infectious diseases worldwide. Uropathogenic Escherichia coli (UPEC) is a major cause of unary tract infection. Due to increasing prevalence of multidrug resistance, alternative methods to eradicate the UPECs are urgently needed. In this respect, phage therapy has been demonstrated to be a good candidate. Here, we described a novel bacteriophage named vB_EcoP-EG1, which can infect several strains of UPEC. Phage morphology and genome sequencing analysis show that vB_EcoP-EG1 belongs to the T7-like Podoviridae. vB_EcoP-EG1 possesses a genome (39,919 bp) containing 51 predicted genes and 149 bp terminal repeats. vB_EcoP-EG1 genome does not encode toxic proteins or proteins related to lysogeny. And no known virulent proteins were found in purified phage particles by mass spectrometry. vB_EcoP-EG1 appeared to be relatively specific and sensitive to clinical UPEC strains, which could infect 10 out of 21 clinical multidrug-resistant UPEC strains. In addition, vB_EcoP-EG1 suspension can eliminate biofilm formed by E. coli MG1655 and multidrug-resistant UPEC strain 390G7. Therefore, we concluded that vB_EcoP-EG1 has desirable characteristics for potential therapy, which may serve as an alternative to antibiotic therapy against urinary tract infections caused by multidrug-resistant UPEC.},
}
@article {pmid30396900,
year = {2018},
author = {Bartolini, M and Cogliati, S and Vileta, D and Bauman, C and Rateni, L and Leñini, C and Argañaraz, F and Francisco, M and Villalba, JM and Steil, L and Völker, U and Grau, R},
title = {Regulation of biofilm aging and dispersal in Bacillus subtilis by the alternative sigma factor SigB.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00473-18},
pmid = {30396900},
issn = {1098-5530},
abstract = {Bacterial biofilms are important in natural settings, biotechnology and medicine. However, regulation of biofilm development and its persistence in different niches is complex and only partially understood. One key step during the biofilm life cycle is dispersal, when motile cells abandon the mature biofilm to spread out and colonize new niches. Here, we show that in the model bacterium Bacillus subtilis the general stress transcription factor SigB is essential for halting detrimental overgrowth of mature biofilm and for triggering dispersal when nutrients become limited. Specifically, SigB-deficient biofilms were larger than wild-type biofilms but exhibited accelerated cell death, significantly greater sensitivity to different stresses and reduced dispersal. Interestingly, the signal detected by SigB to limit biofilm growth was transduced through the RsbP-dependent metabolic arm of the SigB regulatory cascade, which in turn positively controlled expression of SinR, the master regulator of biofilm formation and cell motility. This novel SigB-SinR regulatory circuit might be important in controlling the fitness of biofilms (either beneficial or harmful) in diverse environments.Importance Biofilms are crucial for bacterial survival, adaptation and dissemination in natural, industrial and medical systems. Sessile cells embedded in the self-produced extracellular matrix of the biofilm benefit from a division of labor and are protected from environmental insults. However, as the biofilm ages, cells become stressed because of overcrowding, starvation and accumulation of waste products. How does the sessile biofilm community sense and respond to stressful conditions? Here, we show that in Bacillus subtilis, the transcription factors SigB and SinR control whether cells remain in or leave a biofilm when metabolic conditions become unfavorable. This novel SigB-SinR regulatory circuit might be important for controlling the fitness of biofilms (either beneficial or harmful) in diverse environments.},
}
@article {pmid30396172,
year = {2018},
author = {Lesouhaitier, O and Clamens, T and Rosay, T and Desriac, F and Louis, M and Rodrigues, S and Gannesen, A and Plakunov, VK and Bouffartigues, E and Tahrioui, A and Bazire, A and Dufour, A and Cornelis, P and Chevalier, S and Feuilloley, MGJ},
title = {Host Peptidic Hormones Affecting Bacterial Biofilm Formation and Virulence.},
journal = {Journal of innate immunity},
volume = {},
number = {},
pages = {1-15},
doi = {10.1159/000493926},
pmid = {30396172},
issn = {1662-8128},
abstract = {Bacterial biofilms constitute a critical problem in hospitals, especially in resuscitation units or for immunocompromised patients, since bacteria embedded in their own matrix are not only protected against antibiotics but also develop resistant variant strains. In the last decade, an original approach to prevent biofilm formation has consisted of studying the antibacterial potential of host communication molecules. Thus, some of these compounds have been identified for their ability to modify the biofilm formation of both Gram-negative and Gram-positive bacteria. In addition to their effect on biofilm production, a detailed study of the mechanism of action of these human hormones on bacterial physiology has allowed the identification of new bacterial pathways involved in biofilm formation. In this review, we focus on the impact of neuropeptidic hormones on bacteria, address some future therapeutic issues, and provide a new view of inter-kingdom communication.},
}
@article {pmid30396117,
year = {2018},
author = {Ramalingam, V and Raja, S and Sundaramahalingam, S and Rajaram, R},
title = {Chemical fabrication of graphene oxide nanosheets attenuates biofilm formation of human clinical pathogens.},
journal = {Bioorganic chemistry},
volume = {83},
number = {},
pages = {326-335},
doi = {10.1016/j.bioorg.2018.10.052},
pmid = {30396117},
issn = {1090-2120},
abstract = {Graphene oxide (GO) has been recently attracted considerable interest for its potential applications in physical, chemical and biological properties. In the present study, the GO nanosheets were prepared by a chemical exfoliation technique using a modified Hummers method. Initially, the prepared GO nanosheets were confirmed by UV-vis spectroscopy and further characterized by FE-SEM, Edax, HR-TEM and SAED that demonstrated the formation of GO nanosheets with few layers flat sheet structure with hexagonal lattice crystalline nature. The FTIR spectra revealed the presence of various oxygen containing functional groups has been produced from graphite plane by exfoliation technique. The prepared GO nanosheets showed excellent antibiotic resistant activity against planktonic bacteria and more effective to damage the established biofilms and inhibits the biofilm formation of human clinical pathogens like E. coli and P. aeruginosa. Further, the GO nanosheets were found to be non-toxic to normal mammalian cells and there are no apparent morphological changes were observed in control and treated cells. In conclusion, GO nanosheets were effectively preventing the formation of biofilms and kills the represent bacteria that suggested the GO nanosheets could be used for the prevention and treatment of biofilm-related infections.},
}
@article {pmid30396102,
year = {2018},
author = {Wang, S and Qian, K and Zhu, Y and Yi, X and Zhang, G and Du, G and Tay, JH and Li, J},
title = {Reactivation and pilot-scale application of long-term storage denitrification biofilm based on flow cytometry.},
journal = {Water research},
volume = {148},
number = {},
pages = {368-377},
doi = {10.1016/j.watres.2018.10.072},
pmid = {30396102},
issn = {1879-2448},
abstract = {The work provides a method on the basis of flow cytometry to evaluate the performance of denitrification biofilm during the preservation, reactivation and pilot-scale operation process. The viable cell ratio of denitrification biofilm significantly reduced and further led to the decrease of denitrification capacity after long-term preservation for 5 months. Protein component in tightly bound extracellular polymeric substances (TB-EPS) could serve to enhance microbial adhesion and promote denitrification biofilm formation. With the significant correlation of viable cell ratio and microbial characteristics, 4 °C was more appropriate for preserving denitrification biofilm and conducive to maintain the relatively high denitrification capacity. A maximum denitrification rate of 5.80 gNO3--N/m2·d was obtained in pilot-scale anoxic-oxic (AO) process and Dechloromonas became greater prevalence in denitrification suspended carriers. Furthermore, the enrichment of Pseudomonas, Parcubacteria, Acidovorax, Aquabacterium and Unclassified_Flavobacteriaceae enhanced biofilm formation and nutrient conservation. The significantly positive correlation between viable cell ratio and the ratio of nitrate reduction to COD consumption was discovered, and the indices of Chao, ACE, Shannon and Simpson of denitrification biofilm were positively correlated with viable cell ratio, meaning that flow cytometry analysis was reasonable and suitable to evaluate the performances of denitrification biofilm.},
}
@article {pmid30395927,
year = {2018},
author = {Gao, T and Ding, M and Yang, CH and Fan, H and Chai, Y and Li, Y},
title = {The Phosphotransferase System Gene ptsH Plays an Important Role in MnSOD Production, Biofilm Formation, Swarming motility, and Root Colonization in Bacillus cereus 905.},
journal = {Research in microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.resmic.2018.10.002},
pmid = {30395927},
issn = {1769-7123},
abstract = {The rhizosphere bacterium Bacillus cereus 905 is capable of promoting plant growth through effective colonization on plant roots. The sodA2-encoding manganese-containing superoxide dismutase (MnSOD2) is important for survival of B. cereus 905 in the wheat rhizosphere. However, the genes involved in regulating sodA2 expression and the mechanisms of rhizosphere colonization of B. cereus 905 are not well elucidated. In this study, we found that the deletion of the ptsH gene, which encodes the histidine-phosphorylatable protein (HPr), a component of the phosphotransferase system (PTS), causes a decrease of about 60% in the MnSOD2 expression. Evidences indicate that the ptsH dramatically influences resistance to oxidative stress, glucose uptake, as well as biofilm formation and swarming motility of B. cereus 905. Root colonization assay demonstrated that ΔptsH is defective in colonizing wheat roots, while complementation of the sodA2 gene could partially restore the ability in utilization of arabinose, a non-PTS sugar, and root colonization caused by the loss of the ptsH gene. In toto, based on the current findings, we propose that PtsH contributes to root colonization of B. cereus 905 through multiple indistinct mechanisms, involving PTS and uptake of PTS-sugars, up-regulation of MnSOD2 production, and promotion of biofilm formation and swarming motility.},
}
@article {pmid30394455,
year = {2018},
author = {Pousti, M and Zarabadi, MP and Abbaszadeh Amirdehi, M and Paquet-Mercier, F and Greener, J},
title = {Microfluidic bioanalytical flow cells for biofilm studies: a review.},
journal = {The Analyst},
volume = {},
number = {},
pages = {},
doi = {10.1039/c8an01526k},
pmid = {30394455},
issn = {1364-5528},
abstract = {Bacterial biofilms are among the oldest and most prevalent multicellular life forms on Earth and are increasingly relevant in research areas related to industrial fouling, medicine and biotechnology. The main hurdles to obtaining definitive experimental results include time-varying biofilm properties, structural and chemical heterogeneity, and especially their strong sensitivity to environmental cues. Therefore, in addition to judicious choice of measurement tools, a well-designed biofilm study requires strict control over experimental conditions, more so than most chemical studies. Due to excellent control over a host of physiochemical parameters, microfluidic flow cells have become indispensable in microbiological studies. Not surprisingly, the number of lab-on-chip studies focusing on biofilms and other microbiological systems with expanded analytical capabilities has expanded rapidly in the past decade. In this paper, we comprehensively review the current state of microfluidic bioanalytical research applied to bacterial biofilms and offer a perspective on new approaches that are expected to drive continued advances in this field.},
}
@article {pmid30394387,
year = {2018},
author = {McCall, AD and Edgerton, M},
title = {Real-time Imaging and Quantification of Fungal Biofilm Development Using a Two-Phase Recirculating Flow System.},
journal = {Journal of visualized experiments : JoVE},
volume = {},
number = {140},
pages = {},
doi = {10.3791/58457},
pmid = {30394387},
issn = {1940-087X},
abstract = {In oropharyngeal candidiasis, members of the genus Candida must adhere to and grow on the oral mucosal surface while under the effects of salivary flow. While models for the growth under flow have been developed, many of these systems are expensive, or do not allow imaging while the cells are under flow. We have developed a novel apparatus that allows us to image the growth and development of Candida albicans cells under flow and in real-time. Here, we detail the protocol for the assembly and use of this flow apparatus, as well as the quantification of data that are generated. We are able to quantify the rates that the cells attach to and detach from the slide, as well as to determine a measure of the biomass on the slide over time. This system is both economical and versatile, working with many types of light microscopes, including inexpensive benchtop microscopes, and is capable of extended imaging times compared to other flow systems. Overall, this is a low-throughput system that can provide highly detailed real-time information on the biofilm growth of fungal species under flow.},
}
@article {pmid30393563,
year = {2018},
author = {Antypas, H and Choong, FX and Libberton, B and Brauner, A and Richter-Dahlfors, A},
title = {Rapid diagnostic assay for detection of cellulose in urine as biomarker for biofilm-related urinary tract infections.},
journal = {NPJ biofilms and microbiomes},
volume = {4},
number = {},
pages = {26},
doi = {10.1038/s41522-018-0069-y},
pmid = {30393563},
issn = {2055-5008},
abstract = {The ability of uropathogenic Escherichia coli (UPEC) to adopt a biofilm lifestyle in the urinary tract is suggested as one cause of recurrent urinary tract infections (UTIs). A clinical role of UPEC biofilm is further supported by the presence of bacterial aggregates in urine of UTI patients. Yet, no diagnostics exist to differentiate between the planktonic and biofilm lifestyle of bacteria. Here, we developed a rapid diagnostic assay for biofilm-related UTI, based on the detection of cellulose in urine. Cellulose, a component of biofilm extracellular matrix, is detected by a luminescent-conjugated oligothiophene, which emits a conformation-dependent fluorescence spectrum when bound to a target molecule. We first defined the cellulose-specific spectral signature in the extracellular matrix of UPEC biofilm colonies, and used these settings to detect cellulose in urine. To translate this optotracing assay for clinical use, we composed a workflow that enabled rapid isolation of urine sediment and screening for the presence of UPEC-derived cellulose in <45 min. Using multivariate analysis, we analyzed spectral information obtained between 464 and 508 nm by optotracing of urine from 182 UTI patients and 8 healthy volunteers. Cellulose was detected in 14.8% of UTI urine samples. Using cellulose as a biomarker for biofilm-related UTI, our data provide direct evidence that UPEC forms biofilm in the urinary tract. Clinical implementation of this rapid, non-invasive and user-friendly optotracing diagnostic assay will potentially aid clinicians in the design of effective antibiotic treatment.},
}
@article {pmid30393533,
year = {2018},
author = {Perez-Soto, N and Moule, L and Crisan, DN and Insua, I and Taylor-Smith, LM and Voelz, K and Fernandez-Trillo, F and Krachler, AM},
title = {Correction: Engineering microbial physiology with synthetic polymers: cationic polymers induce biofilm formation in Vibrio cholerae and downregulate the expression of virulence genes.},
journal = {Chemical science},
volume = {9},
number = {39},
pages = {7715},
doi = {10.1039/c8sc90189a},
pmid = {30393533},
issn = {2041-6520},
abstract = {[This corrects the article DOI: 10.1039/C7SC00615B.].},
}
@article {pmid30393211,
year = {2018},
author = {Liaqat, I and Mirza, SA and Iqbal, R and Ali, NM and Saleem, G and Majid, S and Shahid, M},
title = {Flagellar motility plays important role in Biofilm formation of Bacillus cereus and Yersinia enterocolitica.},
journal = {Pakistan journal of pharmaceutical sciences},
volume = {31},
number = {5(Supplementary)},
pages = {2047-2052},
pmid = {30393211},
issn = {1011-601X},
abstract = {Bacteria live either independently as planktonic cells or in organized surface associated colonies called as biofilms. Biofilms play an important role in increased pathogenesis of bacteria and it is assumed that motility is one of the contributing factors towards biofilm initiation. This study was planned to identify the role of flagella in biofilm formation by constructing flagellated (wild type) and physically disrupted variants (non-motile). Total 10 clinical bacterial strains were isolated and characterized. Morphological and biochemical study identified these strains as Enterobacter spp., Pseudomonas spp., Yersinia spp., Escherichia spp., Salmonella spp., Proteus spp., Staphylococcus spp., Streptococcus spp., Lactobacillus spp. and Bacillus spp. Among all strains, two strains including Yersinia spp and Bacillus spp. showed higher antibiotic resistance, hence studied at molecular and physiological level. Biofilm formation capacity of strains was analyzed using three methods including Congo red assay, Test tube assay and Liquid-interface coverslip assay. Afterwards, flagellar disintegration was induced by blending and centrifugation for 5, 10 and 15 minutes. 16S rRNA sequencing showed two strains as Bacillus cereus and Yersinia enterocolitica. Both strains produced significant biofilm by all three above mentioned methods. A motility test of these blended variants showed partial/diminished motility with increased blending time. The significant loss in biofilm formation after 15 minutes blending confirmed the important flagellar contribution to the initiation of biofilm formation. This biofilm defect observed in flagella paralysed/minus variants presumably may be due to defects in attachments to surface at early stages. This study indicated that flagellar motility is crucial initially for surface attachment and subsequently for biofilm formation.},
}
@article {pmid30392371,
year = {2018},
author = {Kunkle, T and Abdeen, S and Salim, N and Ray, AM and Stevens, M and Ambrose, AJ and Victorino, J and Park, Y and Hoang, QQ and Chapman, E and Johnson, SM},
title = {Hydroxybiphenylamide GroEL/ES inhibitors are potent antibacterials against planktonic and biofilm forms of Staphylococcus aureus.},
journal = {Journal of medicinal chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.jmedchem.8b01293},
pmid = {30392371},
issn = {1520-4804},
abstract = {We recently reported the identification of a GroEL/ES inhibitor (1: N-(4-(benzo[ d]thiazol-2-ylthio)-3-chlorophenyl)-3,5-dibromo-2-hydroxybenzamide) that exhibited in vitro antibacterial effects against Staphylococcus aureus comparable to vancomycin, an antibiotic of last resort. To follow-up, we have synthesized 43 compound 1 analogs to determine the most effective functional groups of the scaffold for inhibiting GroEL/ES and killing bacteria. Our results identified that the benzothiazole and hydroxyl groups are important for inhibiting GroEL/ES-mediated folding functions, with the hydroxyl essential for antibacterial effects. Several analogs exhibited >50-fold selectivity indices between antibacterial efficacy and cytotoxicity to human liver and kidney cells in cell culture. We found that MRSA were not able to easily generate acute resistance to lead inhibitors in a gain-of-resistance assay, and that lead inhibitors were able to permeate through established S. aureus biofilms and maintain their bactericidal effects.},
}
@article {pmid30392142,
year = {2018},
author = {Vilarrasa, J and Delgado, LM and Galofré, M and Àlvarez, G and Violant, D and Manero, JM and Blanc, V and Gil, FJ and Nart, J},
title = {In vitro evaluation of a multispecies oral biofilm over antibacterial coated titanium surfaces.},
journal = {Journal of materials science. Materials in medicine},
volume = {29},
number = {11},
pages = {164},
doi = {10.1007/s10856-018-6168-8},
pmid = {30392142},
issn = {1573-4838},
abstract = {Peri-implantitis is an infectious disease that affects the supporting soft and hard tissues around dental implants and its prevalence is increasing considerably. The development of antibacterial strategies, such as titanium antibacterial-coated surfaces, may be a promising strategy to prevent the onset and progression of peri-implantitis. The aim of this study was to quantify the biofilm adhesion and bacterial cell viability over titanium disc with or without antibacterial surface treatment. Five bacterial strains were used to develop a multispecies oral biofilm. The selected species represent initial (Streptococcus oralis and Actinomyces viscosus), early (Veillonella parvula), secondary (Fusobacterium nucleatum) and late (Porphyromonas gingivalis) colonizers. Bacteria were sequentially inoculated over seven different types of titanium surfaces, combining different roughness level and antibacterial coatings: silver nanoparticles and TESPSA silanization. Biofilm formation, cellular viability and bacterial quantification over each surface were analyzed using scanning electron microscopy, confocal microscopy and real time PCR. Biofilm formation over titanium surfaces with different bacterial morphologies could be observed. TESPSA was able to significantly reduce the cellular viability when compared to all the surfaces (p < 0.05). Silver deposition on titanium surface did not show improved results in terms of biofilm adhesion and cellular viability when compared to its corresponding non-coated surface. The total amount of bacterial biofilm did not significantly differ between groups (p > 0.05). TESPSA was able to reduce biofilm adhesion and cellular viability. However, silver deposition on titanium surface seemed not to confer these antibacterial properties.},
}
@article {pmid30391896,
year = {2018},
author = {Cao, X and Zhang, S and Wang, H and Li, X},
title = {Azo dye as part of co-substrate in a biofilm electrode reactor-microbial fuel cell coupled system and an analysis of the relevant microorganisms.},
journal = {Chemosphere},
volume = {216},
number = {},
pages = {742-748},
doi = {10.1016/j.chemosphere.2018.10.203},
pmid = {30391896},
issn = {1879-1298},
abstract = {In general, refractory organics were hardly used as co-substrate in bioelectrochemical system. This study established a coupled bioelectrochemical system composed of a biofilm electrode reactor and a microbial fuel cell for using the azo dye X-3B as part of co-substrate. The two units degraded the azo dye X-3B stepwise while using it as part of co-substrate. Our results indicated that the removal efficiency of X-3B increased 28.5% using the coupled system compared with a control system. Moreover, the addition of the co-substrate glucose, which was necessary for MFC electricity generation, was reduced on the premise of stable removal efficiency in the coupled system to prevent resource waste due to using X-3B as part of co-substrate. The intermediate products of X-3B degradation were further explored using gas chromatography-mass spectrometry and a X-3B degradation pathway was proposed at the same time. Microbial communities were analyzed, illustrating that the mechanism of X-3B degradation was dependent on bioelectrochemistry rather than on microbial degradation.},
}
@article {pmid30391649,
year = {2018},
author = {Anupama, R and Lulu, S and Madhusmita, R and Vino, S and Mukherjee, A and Babu, S},
title = {Insights into the interaction of key biofilm proteins in Pseudomonas aeruginosa PAO1 with TiO2 nanoparticle: An in silico analysis.},
journal = {Journal of theoretical biology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jtbi.2018.10.057},
pmid = {30391649},
issn = {1095-8541},
abstract = {Pseudomonas aeruginosa is a pathogenic biofilm forming bacteria which exist in wide range of environments such as water, soil and human body. In an earlier study, we used a system biology approach based analysis of biofilm forming genes of P. aeruginosa and their possible role in TiO2 nanoparticle binding. The major protein of P. aeruginosa targeted by TiO2 was found to be KatA, a major catalase required for H2O2 resistance and acute virulence and the direct interacting protein partners of KatA were found to be DnaK, Hfq, RpoA and RpoS. To understand the protein-protein physical interaction characteristic of these key proteins involved in biofilm related processes, homology modeling, docking and molecular dynamic simulation were performed. For all these proteins, physical and chemical properties, amino acid composition, nest and cleft analysis were performed using online tools. The interactions between TiO2NPs-KatA and four protein-protein complexes such as KatA-DnaK, KatA-Hfq, KatA-RpoA and KatA-RpoS were studied. Our results indicate that all four key proteins and TiO2NPs can have stable complexation with KatA. The study has given enough clues to understand the interaction of TiO2NPs with P. aeruginosa biofilm in natural environment. Further investigations could lead to development of TiO2NPs based therapeutic and sanitary interventions to combat this pathogenic bacterium.},
}
@article {pmid30390625,
year = {2018},
author = {Cruz, CD and Shah, S and Tammela, P},
title = {Defining conditions for biofilm inhibition and eradication assays for Gram-positive clinical reference strains.},
journal = {BMC microbiology},
volume = {18},
number = {1},
pages = {173},
doi = {10.1186/s12866-018-1321-6},
pmid = {30390625},
issn = {1471-2180},
support = {304697//Academy of Finland/ ; 277001//Academy of Finland/ ; },
abstract = {BACKGROUND: Biofilms are formed by a complex bacterial community encapsulated by a polymeric matrix, with strong adherent properties and persistent phenotype. Biofilms are considered one of the most challenging areas of modern medicine. Existing antibiotics have been developed against free-floating bacterial cells, and thus, many treatments of biofilm-related infection fail. In this study, we compared the effects of different media on biofilm growth of clinical reference strains of Staphylococci and Enterococci, including multi-drug resistant representatives. Further, we optimized the resazurin-based assay for determining the minimal biofilm inhibitory concentration (MBIC) of standard antibiotics, and evaluated its use for the determination of minimal biofilm eradication concentration (MBEC).<br><br>RESULTS: We showed that tryptic soy broth supplemented with 1% glucose was an optimal media for maximum biofilm growth of all strains tested, with an extended incubation time for Enterococci. A range of parameters were tested for the resazurin assay, including concentration, temperature and time of incubation. Using quality parameters to analyze the assay's performance, the conditions for the resazurin assay were set as follows: 4 μg/mL and 8 μg/mL, with incubation at 25 °C for 20 min and 40 min for Staphylococci and Enterococci, respectively.<br><br>CONCLUSIONS: In summary, we defined conditions for optimal biofilm growth and for standardized resazurin assay for MBIC determination against six Gram-positive clinical reference strains. We also observed that MBEC determination by the resazurin-based assay is limited due to the poor detection limit of the assay. Complementary cell counting data is needed for precise determination of MBEC.},
}
@article {pmid30390459,
year = {2018},
author = {Purswani, J and Guisado, IM and Coello-Cabezas, J and González-López, J and Pozo, C},
title = {Social microbial inocula confer functional stability in a methyl tert-butyl ether extractive membrane biofilm bioreactor.},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {244},
number = {},
pages = {855-860},
doi = {10.1016/j.envpol.2018.10.100},
pmid = {30390459},
issn = {1873-6424},
abstract = {Methyl tert-butyl ether (MTBE) degradation technologies based on two-phase partitioning systems such as extractive membrane biofilm reactors (EMBFR) permit separation of biological and contaminant compartments, thus allowing optimization of the biological section. In this study, we set-up an EMBFR with three MTBE-degrading and cooperating strains (termed social biofilm: Agrobacterium sp. MS2, Paenibacillus etheri SH7T and Rhodococcus ruber EE6). The removal efficiency of the social-biofilm EMBFR was 80%, and functional stability was observed in the reactor, i.e. more efficient than previous studies (single-strain inoculated EMBFR, <50% removal efficiency and unstable function). Metabolite tert-butyl alcohol was not observed, and the EC50 values were higher than those observed in single-strain EMBFRs. Comparative analysis of the MTBE enzymatic pathway and the social-biofilm was performed, where the mechanism of cooperation observed within the social-biofilm is likely due to enzymatic redundancy. Functional outcomes were equal to previous batch tests, hence 100% scalability was obtained. Overall, higher functional and stability outcomes are obtained with the use of the social-biofilm in an MTBE-EMBFR.},
}
@article {pmid30390102,
year = {2018},
author = {Huang, N and Pu, X and Zhang, J and Shen, H and Yang, Q and Wang, Z and Lin, B},
title = {In Vitro Formation of Dickeya zeae MS1 Biofilm.},
journal = {Current microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00284-018-1593-y},
pmid = {30390102},
issn = {1432-0991},
support = {2015A030312002//Natural Science Foundation of Guangdong Province/ ; 2014J4500034//Guangzhou Science and Technology Projects (CN)/ ; 201515//President Foundation of the Guangdong Academy of Agricultural Sciences/ ; },
abstract = {Bacterial soft rot caused by Dickeya zeae MS1 (Erwinia chrysanthemi) is one of the most devastating banana diseases worldwide. However, knowledge of the development and ecological interactions of D. zeae MS1 biofilm is limited. Here, we visualized the development and architecture of D. zeae MS1 biofilm using confocal laser scanning microscopy, and we evaluated the ability of D. zeae MS1 to form biofilms under different environmental conditions (carbon sources, temperatures, pH levels and mineral elements) using a microtiter plate assay. We found that the development of D. zeae MS1 biofilm could be categorized into four phases and that mature biofilm consisted of a highly organized architecture of both bacterial cells and a self-produced matrix of extracellular polysaccharides. Furthermore, sucrose was the most suitable carbon source for supporting the growth of biofilm cells and that 32 °C and pH 7.0 were the most favorable of the temperatures and pH levels examined. Meanwhile, the addition of Ca2+, Fe2+, K+ and Na+ enhanced the formation of biofilm in minimal medium cultures, whereas 2.5 mM Cu2+ and Mn2+ was inhibitory. A better understanding of biofilm formation under different environmental parameters will improve our knowledge of the growth kinetics of D. zeae MS1 biofilm.},
}
@article {pmid30389224,
year = {2018},
author = {Ramalingam, K and Amaechi, BT},
title = {Antimicrobial effect of herbal extract of Acacia arabica with triphala on the biofilm forming cariogenic microorganisms.},
journal = {Journal of Ayurveda and integrative medicine},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jaim.2018.01.005},
pmid = {30389224},
issn = {0975-9476},
abstract = {BACKGROUND: Dental caries is a biofilm-related infectious disease with a multifactorial etiology, over five billion inhabitants have affected worldwide due to this disease.<br><br>OBJECTIVE: Antimicrobial efficacy of a mixed herbal powder extract (MHPE) against cariogenic microorganisms was investigated.<br><br>MATERIALS AND METHODS: MIC, MBC, kinetics of killing, biofilm disruption and anticaries effect of MHPE were determined. For biofilm disruption, biofilms of Streptococcus mutans, Lactobacillus casei, Actinomyces viscosus and Candida albicans were treated with MHPE for 30 min and attached cells were quantified after staining. For live/dead staining biofilm assay, S. mutans biofilm treated with MHPE for 1min, 5min and 1 h was examined with confocal laser scanning system after live/dead staining. Efficacy was experimented by structural quality using Scanning Electron Microscope (SEM). Anticaries effect was determined by formation of caries-like lesion in continuous flow biofilm model.<br><br>RESULTS: MHPE exhibited inhibition zones ranging from 12.5 to 24.0 mm. The highest inhibition zone was recorded at concentration of 50 μg/ml. MIC for S. mutans was between 12.23 and 36.7 μg/ml, while the MBC values ranged from 36.7 to 110.65 μg/ml. Inhibitory concentration of MHPE was three fold higher than CHLX. Significant reduction of cell count (49-95%) was observed with increasing time and higher concentration. Percentage biofilm reduction compare with negative control was 96.9% (A. viscosus), 94% (C. albicans), 99.8% (L. casei) and 91.7% (S. mutans). For MHPE-treated biofilm, live/dead staining demonstrated significant (p < 0.05) higher in deceased red fluorescence areas in all kinetics points from 53.6% (1min) to 85% (1h). SEM confirmed the damage in the outer layers of S. mutans. MHPE has components with effective antibacterial activity against caries-inducing microorganisms.<br><br>CONCLUSION: The anti-adherence and anti-biofilm effect as well as the faster killing activity suggests that MHPE formula has effective antibacterial activity and could be a useful source of anti-cariogenic agents in near future.},
}
@article {pmid30387879,
year = {2018},
author = {Carreiro, AF and Delben, JA and Guedes, S and Silveira, EJ and Janal, MN and Vergani, CE and Pushalkar, S and Duarte, S},
title = {Low-temperature plasma on peri-implant related biofilm and gingival tissue.},
journal = {Journal of periodontology},
volume = {},
number = {},
pages = {},
doi = {10.1002/JPER.18-0366},
pmid = {30387879},
issn = {1943-3670},
abstract = {BACKGROUND: Evaluate the effect of Low Temperature Plasma (LTP) on an anaerobic biofilm and on the biological response of an in vitro reconstituted gingival epithelium tissue.<br><br>METHODS: P. gingivalis W83 biofilm was cultured on titanium discs and reconstituted gingival tissue were submitted to similar treatment conditions.<br><br>TREATMENTS: LTP1 - plasma treatment for 1 min, LTP3 - plasma treatment for 3 min, CHX - 0.2% chlorhexidine for 1 min, GAS - gas only (no plasma) for 3 min, NEGATIVE - no treatment. TRITON group was included as a positive control for tissue analysis. Counting of viable colony forming units (CFU/mL) and confocal laser scanning microscopy were performed to evaluate LTP's antimicrobial effect. EpiGingival™ tissue was evaluated through cytotoxocity, viability, histology and imunnohistochemistry (Ki67, VEGF-A and TUNEL expression).<br><br>RESULTS: LTP1 and LTP3 significantly reduced CFU/mL in comparison to the negative control (ρ < 0.001), but it was not as effective as the positive control (CHX). Low cytotoxicity and high viability were observed in gingival epithelium of NEGATIVE, GAS, CHX and both LTP groups. The morphological analysis revealed minor cell damage in the plasma groups (score 1). LTP1, LTP3, GAS and NEGATIVE groups exhibited less than 5% of basal layer positive cells. LTP1, LTP3, GAS and CHX groups were not positive for TUNEL assay. LTP1 and LTP3 showed the most positivity for VEGF.<br><br>CONCLUSIONS: LTP treatment can be considered an effective method for reducing P. gingivalis biofilm on implant surfaces being safe for the gingival epithelium. Furthermore, plasma treatment may be associated with cell repair. This article is protected by copyright. All rights reserved.},
}
@article {pmid30387769,
year = {2018},
author = {Vogt, MS and Völpel, SL and Albers, SV and Essen, LO and Banerjee, A},
title = {Crystal structure of an Lrs14-like archaeal biofilm regulator from Sulfolobus acidocaldarius.},
journal = {Acta crystallographica. Section D, Structural biology},
volume = {74},
number = {Pt 11},
pages = {1105-1114},
doi = {10.1107/S2059798318014146},
pmid = {30387769},
issn = {2059-7983},
abstract = {The small winged helix-turn-helix (wHTH) proteins of the Lrs14 family are major transcriptional regulators and act as archaeal biofilm regulators (AbfRs) in the crenarchaeote Sulfolobus acidocaldarius. Here, the first crystal structure of an AbfR ortholog, AbfR2, the deletion of which is known to impair biofilm formation, is presented. Like most other wHTH orthologs, AbfR2 is dimeric in solution as well as in its 2.45 Å resolution crystal structure. Given the presence of three independent AbfR2 dimers in the asymmetric unit, the crystal structure shows a considerable degree of conformational variation within the dimer, the antiparallel orientations of which are stabilized by coiled-coil interaction between H4 helices. Conserved anchor interactions between helices H0 and H4 of AbfR2 further contribute to dimer stabilization. The combined structural and bioinformatic analysis reveals cluster-specific structural differences between different members of the Lrs14 protein family.},
}
@article {pmid30386734,
year = {2018},
author = {Dinamarca, MA and Eyzaguirre, J and Baeza, P and Aballay, P and Canales, C and Ojeda, J},
title = {A new functional biofilm biocatalyst for the simultaneous removal of dibenzothiophene and quinoline using Rhodococcus rhodochrous and curli amyloid overproducer mutants derived from Cobetia sp. strain MM1IDA2H-1.},
journal = {Biotechnology reports (Amsterdam, Netherlands)},
volume = {20},
number = {},
pages = {e00286},
doi = {10.1016/j.btre.2018.e00286},
pmid = {30386734},
issn = {2215-017X},
abstract = {Biocatalyst systems based on biofilms were developed to remove nitrogen and sulfur-containing heterocyclic hydrocarbons using Cobetia sp. strain MM1IDA2H-1 and Rhodococcus rhodochrous. The curli overproducers mutants CM1 and CM4 were derived from Cobetia sp. strain and used to build monostrain biofilms to remove quinoline; and together with R. rhodochrous to simultaneously remove quinoline and dibenzothiophene using mixed biofilms. The quinoline removal using biofilms were 96% and 97% using CM1 or CM4 curli overproducers respectively, whereas bacterial suspensions assays yielded 19% and 24% with the same strains. At the other hand, the simultaneous removal of quinoline and dibenzothiophene using mixed biofilms were respectively 50% and 58% using strains R. rhodochrous with CM1 and 75% and 50% using R. rhodochrous with CM4. Results show that biofilms were more efficient than bacterial suspension assays and that in mixed biofilms the shared surface area by two or more bacteria could affect the final yield.},
}
@article {pmid30385204,
year = {2018},
author = {Surgers, L and Boyd, A and Girard, PM and Arlet, G and Decré, D},
title = {Biofilm formation by ESBL-producing strains of Escherichia coli and Klebsiella pneumoniae.},
journal = {International journal of medical microbiology : IJMM},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijmm.2018.10.008},
pmid = {30385204},
issn = {1618-0607},
abstract = {OBJECTIVES: Biofilm production in extended spectrum β-lactamase (ESBL)-producing Enterobacteriaceae provides a favourable environment for the exchange of antibiotic-resistance genes and could facilitate widespread dissemination. We aimed to assess biofilm development in ESBL-producing E. coli and K. pneumoniae isolates and determine how development relates to microbiological characteristics and clinical outcomes.<br><br>METHODS: 147 ESBL-producing E. coli and 82 K. pneumoniae were genetically characterized. Biofilm formation was measured at 1.5, 4, 6, and 24 h during culture in blood heart infusion using a microbead immobilization assay (BioFilm Ring test®). Results were given as biofilm formation index (BFI) with lower values indicating increased presence of biofilm (range = 0-21).<br><br>RESULTS: In total, 57.1% of strains were strong producers of biofilm (BFI < 2), whereas 13.4% lacked biofilm production (BFI > 18). Standard biofilm production (BFI < 7) was common in E. coli isolates (61.9%). For E. coli, biofilm production was less frequently observed in ST131 clones (p = 0.03) but more frequently in strains harbouring toxin (p = 0.008) or adhesin (p = 0.008) virulence factor genes. Despite almost all K. pneumoniae having standard biofilm production (90.2%), there was a 2.4-times higher odds of observing biofilm in ST29/147/323 versus other ST-types (p = 0.13). Patients with standard biofilm producing isolates were not at increased risk of transfer to intensive-care (odds-ratio=2.80, 95%CI=0.59-13.21) or death within 12-months (odds-ratio=1.61, 95%CI=0.75-3.43).<br><br>CONCLUSION: In these ESBL-producing strains, biofilm production is linked to certain virulence factors in E. coli and is common in K. pneumoniae. Further exploration of whether biofilm production increases dissemination and risk of severe clinical outcomes is needed in larger collections of isolates.},
}
@article {pmid30384254,
year = {2018},
author = {Khalid, HF and Tehseen, B and Sarwar, Y and Hussain, SZ and Khan, WS and Raza, ZA and Bajwa, SZ and Kanaras, AG and Hussain, I and Rehman, A},
title = {Biosurfactant coated silver and iron oxide nanoparticles with enhanced anti-biofilm and anti-adhesive properties.},
journal = {Journal of hazardous materials},
volume = {364},
number = {},
pages = {441-448},
doi = {10.1016/j.jhazmat.2018.10.049},
pmid = {30384254},
issn = {1873-3336},
abstract = {Pseudomonas aeruginosa and Staphylococcus aureus are among the hazardous biofilm forming bacteria ubiquitous in industrial/clinical wastes. Serious efforts are required to develop effective strategies to control surface-growing antibiotic resistant pathogenic bacterial communities which they are emerging as a global health issue. Blocking hazardous biofilms would be a useful aspect of biosurfactant coated nanoparticles (NPs). In this regard, we report a facile method for the synthesis of rhamnolipid (RL) coated silver (Ag) and iron oxide (Fe3O4) NPs and propose the mechanism of their synergistic antibacterial and anti-adhesive properties against biofilms formed by P. aeruginosa and S. aureus. These NPs demonstrated excellent anti-biofilm activity not only during the biofilms formation but also on the pre-formed biofilms. Mechanistically, RL coated silver (35 nm) and Fe3O4 NPs (48 nm) generate reactive oxygen species, which contribute to the antimicrobial activity. The presence of RLs shell on the nanoparticles significantly reduces the cell adhesion by modifying the surface hydrophobicity and hence enhancing the anti-biofilm property of NPs against both mentioned strains. These findings suggest that RL coated Ag and Fe3O4 NPs may be used as potent alternate to reduce the infection severity by inhibiting the biofilm formation and, therefore, they possess potential biomedical applications for antibacterial coatings and wound dressings.},
}
@article {pmid30384192,
year = {2018},
author = {Ripolles-Avila, C and Cervantes-Huaman, BH and Hascoët, AS and Yuste, J and Rodríguez-Jerez, JJ},
title = {Quantification of mature Listeria monocytogenes biofilm cells formed by an in vitro model: A comparison of different methods.},
journal = {International journal of food microbiology},
volume = {289},
number = {},
pages = {209-214},
doi = {10.1016/j.ijfoodmicro.2018.10.020},
pmid = {30384192},
issn = {1879-3460},
abstract = {The presence of biofilms in food industrial environments is one of the main causes associated with food product contamination by L. monocytogenes. Biofilm control in the food industry is very relevant to public health and finding reliable and realistic quantification methods is essential. The aim of this study is to compare five L. monocytogenes biofilm quantification methods - conventional plate count, TEMPO, DEM, VIDAS and qPCR - and to examine a biodetector to visually detect biofilms in industrial settings. Results show that depending on the biofilm matrix production, the recovery of cells that conform the biofilm can be low and therefore, if it is an indirect method, microbial counts can be underestimated. At a species level, the methods that did not present significant differences were plate count, TEMPO (P = 0.998), DEM and qPCR (P = 0.508), so correlation studies were performed which established high correlation for plate count and TEMPO, but not for DEM and qPCR. The VIDAS method was adjusted so that it could quantify the biofilms, but the standard curve only allowed counts from 7 Log CFU cm-2. Results also revealed that the different strains of L. monocytogenes possess different biofilm-forming abilities, although it was not possible to correlate the capacity to produce these structures with the distinct serotypes. Last, visually detecting biofilms on stainless steel coupons proved that in industrial environments nowadays they can be rapidly and qualitatively detected so that relevant decisions can immediately be taken.},
}
@article {pmid30383525,
year = {2018},
author = {Nolan, LM and Whitchurch, CB and Barquist, L and Katrib, M and Boinett, CJ and Mayho, M and Goulding, D and Charles, IG and Filloux, A and Parkhill, J and Cain, AK},
title = {A global genomic approach uncovers novel components for twitching motility-mediated biofilm expansion in Pseudomonas aeruginosa.},
journal = {Microbial genomics},
volume = {},
number = {},
pages = {},
doi = {10.1099/mgen.0.000229},
pmid = {30383525},
issn = {2057-5858},
abstract = {Pseudomonas aeruginosa is an extremely successful pathogen able to cause both acute and chronic infections in a range of hosts, utilizing a diverse arsenal of cell-associated and secreted virulence factors. A major cell-associated virulence factor, the Type IV pilus (T4P), is required for epithelial cell adherence and mediates a form of surface translocation termed twitching motility, which is necessary to establish a mature biofilm and actively expand these biofilms. P. aeruginosa twitching motility-mediated biofilm expansion is a coordinated, multicellular behaviour, allowing cells to rapidly colonize surfaces, including implanted medical devices. Although at least 44 proteins are known to be involved in the biogenesis, assembly and regulation of the T4P, with additional regulatory components and pathways implicated, it is unclear how these components and pathways interact to control these processes. In the current study, we used a global genomics-based random-mutagenesis technique, transposon directed insertion-site sequencing (TraDIS), coupled with a physical segregation approach, to identify all genes implicated in twitching motility-mediated biofilm expansion in P. aeruginosa. Our approach allowed identification of both known and novel genes, providing new insight into the complex molecular network that regulates this process in P. aeruginosa. Additionally, our data suggest that the flagellum-associated gene products have a differential effect on twitching motility, based on whether components are intra- or extracellular. Overall the success of our TraDIS approach supports the use of this global genomic technique for investigating virulence genes in bacterial pathogens.},
}
@article {pmid30382617,
year = {2018},
author = {Gazizov, A and Smolobochkin, AV and Muravyeva, EA and Vagapova, LI and Knyazeva, IR and Voronina, JK and Burilov, AR and Pudovik, MA and Gildebrant, AV and Sazykin, IS and Sazykina, MA},
title = {Synthesis and Evaluation of Water-Soluble 1-Sulfonyl-2-Arylpyrrolidine Derivatives as Bacterial Biofilm Formation Inhibitors.},
journal = {Chemistry &amp; biodiversity},
volume = {},
number = {},
pages = {},
doi = {10.1002/cbdv.201800490},
pmid = {30382617},
issn = {1612-1880},
abstract = {The approach to the novel 1-((2-aminoethyl)sulfonyl)-2-arylpyrrolidines via unique intramolecular cyclisation / aza-Michael reactions of N-(4,4-diethoxybutyl)ethenesulfonamide have been developed, which benefits from high yields of target compounds, mild reaction conditions, usage of inexpensive and low-toxic reagents, and allows for wide variability in both amine and aryl moieties. Biotesting with whole-cell luminescent bacterial biosensors responding to DNA damage showed that all tested compounds are not genotoxic. Tested compounds differently affect the formation of biofilms by Vibrio aquamarinus DSM 26054. Some of the tested compounds were found to suppress the bacterial biofilms growth and thus are promising candidates for further studies.},
}
@article {pmid30381653,
year = {2018},
author = {Kim, MK and Lee, TG and Jung, M and Park, KH and Chong, Y},
title = {In Vitro Synergism and Anti-biofilm Activity of Quercetin-Pivaloxymethyl Conjugate against Staphylococcus aureus and Enterococcus Species.},
journal = {Chemical &amp; pharmaceutical bulletin},
volume = {66},
number = {11},
pages = {1019-1022},
doi = {10.1248/cpb.c18-00380},
pmid = {30381653},
issn = {1347-5223},
abstract = {Upon single treatment against Staphylococus aureus, quercetin-pivaloxymethyl conjugate (Q-POM) had antibacterial activities with minimum inhibitory concentrations (MICs) of 16-32 mg/L. Q-POM showed MIC of 32 mg/L against vancomycin-resistant Enterococcus faceium (VRE), which is remarkably lower than other antibiotics investigated (≥256 mg/L). Under sub-MIC concentrations, Q-POM potentiated the activity of ampicillin, cefepime, and vancomycin against S. aureus and Enterococcus (including highly resistant strains such as hetero-resistant vancomycin-intermediate S. aureus (hVISA), vancomycin-intermediate S. aureus (VISA), and VRE), by decreasing the MICs of these antibiotics by 4-128 folds. Q-POM was found to be partially synergistic with ampicillin and cefepime against S. aureus and Enterococcus, while it was strongly synergistic with vancomycin. Q-POM at 5 mg/L inhibited the formation of biofilms of S. aureus by 24-83% and VRE by 70%. Additionally, Q-POM inhibited the hemolytic activity of S. aureus in a dose-dependent manner. Cytotoxic activity was evaluated in human liver epithelial cells (HepG2), and the 50% cytotoxicity concentration (CC50) value of Q-POM was higher than 50 mg/L. These results indicate the potential use of Q-POM in treatment of methicillin-resistant Staphylococcus aureus (MRSA) and VRE infections.},
}
@article {pmid30380779,
year = {2018},
author = {Yuyama, KT and Wendt, L and Surup, F and Kretz, R and Chepkirui, C and Wittstein, K and Boonlarppradab, C and Wongkanoun, S and Luangsa-Ard, J and Stadler, M and Abraham, WR},
title = {Cytochalasans Act as Inhibitors of Biofilm Formation of Staphylococcus Aureus.},
journal = {Biomolecules},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/biom8040129},
pmid = {30380779},
issn = {2218-273X},
support = {645701//Horizon 2020 Framework Programme/ ; },
abstract = {During the course of our ongoing work to discover new inhibitors of biofilm formation of Staphylococcus aureus from fungal sources, we observed biofilm inhibition by cytochalasans isolated from cultures of the ascomycete Hypoxylon fragiforme for the first time. Two new compounds were purified by a bioassay-guided fractionation procedure; their structures were elucidated subsequently by nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HR-MS). This unexpected finding prompted us to test further cytochalasans from other fungi and from commercial sources for comparison. Out of 21 cytochalasans, 13 showed significant inhibition of Staphylococcus aureus biofilm formation at subtoxic levels. These findings indicate the potential of cytochalasans as biofilm inhibitors for the first time, also because the minimum inhibitory concentrations (MIC) are independent of the anti-biofilm activities. However, cytochalasans are known to be inhibitors of actin, making some of them very toxic for eukaryotic cells. Since the chemical structures of the tested compounds were rather diverse, the inclusion of additional derivatives, as well as the evaluation of their selectivity against mammalian cells vs. the bacterium, will be necessary as next step in order to develop structure-activity relationships and identify the optimal candidates for development of an anti-biofilm agent.},
}
@article {pmid30380712,
year = {2018},
author = {Bernal-Mercado, AT and Vazquez-Armenta, FJ and Tapia-Rodriguez, MR and Islas-Osuna, MA and Mata-Haro, V and Gonzalez-Aguilar, GA and Lopez-Zavala, AA and Ayala-Zavala, JF},
title = {Comparison of Single and Combined Use of Catechin, Protocatechuic, and Vanillic Acids as Antioxidant and Antibacterial Agents against Uropathogenic Escherichia Coli at Planktonic and Biofilm Levels.},
journal = {Molecules (Basel, Switzerland)},
volume = {23},
number = {11},
pages = {},
doi = {10.3390/molecules23112813},
pmid = {30380712},
issn = {1420-3049},
abstract = {The objective of this study was to evaluate the effect of combining catechin, protocatechuic, and vanillic acids against planktonic growing, adhesion, and biofilm eradication of uropathogenic Escherichia coli (UPEC), as well as antioxidant agents. The minimum inhibitory concentrations (MIC) of protocatechuic, vanillic acids and catechin against the growth of planktonic bacteria were 12.98, 11.80, and 13.78 mM, respectively. Mixing 1.62 mM protocatechuic acid + 0.74 mM vanillic acid + 0.05 mM catechin resulted in a synergistic effect acting as an MIC. Similarly, the minimum concentrations of phenolic compounds to prevent UPEC adhesion and biofilm formation (MBIC) were 11.03 and 7.13 mM of protocatechuic and vanillic acids, respectively, whereas no MBIC of catechin was found. However, combinations of 1.62 mM protocatechuic acid + 0.74 mM vanillic acid + 0.05 mM catechin showed a synergistic effect acting as MBIC. On the other hand, the minimum concentrations to eradicate biofilms (MBEC) were 25.95 and 23.78 mM, respectively. The combination of 3.20 mM protocatechuic acid, 2.97 mM vanillic acid, and 1.72 mM catechin eradicated pre-formed biofilms. The antioxidant capacity of the combination of phenolics was higher than the expected theoretical values, indicating synergism by the DPPH•, ABTS, and FRAP assays. Effective concentrations of catechin, protocatechuic, and vanillic acids were reduced from 8 to 1378 times when combined. In contrast, the antibiotic nitrofurantoin was not effective in eradicating biofilms from silicone surfaces. In conclusion, the mixture of phenolic compounds was more effective in preventing cell adhesion and eradicating pre-formed biofilms of uropathogenic E. coli than single compounds and nitrofurantoin, and showed antioxidant synergy.},
}
@article {pmid30379419,
year = {2018},
author = {Zhao, X and Yu, Y and Zhang, X and Huang, B and Bai, P and Xu, C and Li, D and Zhang, B and Liu, C},
title = {Decreased biofilm formation ability of Acinetobacter baumannii after spaceflight on China's Shenzhou 11 spacecraft.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e763},
doi = {10.1002/mbo3.763},
pmid = {30379419},
issn = {2045-8827},
support = {BWS17C030//Major Project of Military Medicine/ ; 2016M592928//China Postdoctoral Science Foundation/ ; 2018T111136//China Postdoctoral Science Foundation/ ; 81600011//National Natural Science Foundation of China/ ; 2015ZX09J15102-003//National Significant Science Foundation/ ; 2014CB744400//National Basic Research Program of China (973 program)/ ; },
abstract = {China has prepared for construction of a space station by the early 2020s. The mission will require astronauts to stay on the space station for at least 180 days. Microbes isolated from the International Space Station (ISS) have shown profound resistance to clinical antibiotics and environmental stresses. Previous studies have demonstrated that the space environment could affect microbial survival, growth, virulence, biofilms, metabolism, as well as their antibiotic-resistant phenotypes. Furthermore, several studies have reported that astronauts experience a decline in their immunity during long-duration spaceflights. Monitoring microbiomes in the ISS or the spacecraft will be beneficial for the prevention of infection among the astronauts during spaceflight. The development of a manned space program worldwide not only provides an opportunity to investigate the impact of this extreme environment on opportunistic pathogenic microbes, but also offers a unique platform to detect mutations in pathogenic bacteria. Various microorganisms have been carried on a spacecraft for academic purposes. Acinetobacter baumannii is a common multidrug-resistant bacterium often prevalent in hospitals. Variations in the ability to cope with environmental hazards increase the chances of microbial survival. Our study aimed to compare phenotypic variations and analyze genomic and transcriptomic variations in A. baumannii among three different groups: SS1 (33 days on the Shenzhou 11 spacecraft), GS1 (ground control), and Aba (reference strain). Consequently, the biofilm formation ability of the SS1 strain decreased after 33 days of spaceflight. Furthermore, high-throughput sequencing revealed that some differentially expressed genes were downregulated in the SS1 strain compared with those in the GS1 strain. In conclusion, this present study provides insights into the environmental adaptation of A. baumannii and might be useful for understanding changes in the opportunistic pathogenic microbes on our spacecraft and on China's future ISS.},
}
@article {pmid30378750,
year = {2018},
author = {Weisel, JW and Litvinov, RI},
title = {Keeping it clean: clot biofilm to wall out bacterial invasion.},
journal = {Journal of thrombosis and haemostasis : JTH},
volume = {},
number = {},
pages = {},
doi = {10.1111/jth.14309},
pmid = {30378750},
issn = {1538-7836},
}
@article {pmid30377283,
year = {2018},
author = {Hathroubi, S and Zerebinski, J and Ottemann, KM},
title = {Helicobacter pylori Biofilm Involves a Multigene Stress-Biased Response, Including a Structural Role for Flagella.},
journal = {mBio},
volume = {9},
number = {5},
pages = {},
doi = {10.1128/mBio.01973-18},
pmid = {30377283},
issn = {2150-7511},
abstract = {Helicobacter pylori has an impressive ability to persist chronically in the human stomach. Similar characteristics are associated with biofilm formation in other bacteria. The H. pylori biofilm process, however, is poorly understood. To gain insight into this mode of growth, we carried out comparative transcriptomic analysis between H. pylori biofilm and planktonic cells, using the mouse-colonizing strain SS1. Optimal biofilm formation was obtained with a low concentration of serum and 3 days of growth, conditions that caused both biofilm and planktonic cells to be ∼80% coccoid. Transcriptome sequencing (RNA-seq) analysis found that 8.18% of genes were differentially expressed between biofilm and planktonic cell transcriptomes. Biofilm-downregulated genes included those involved in metabolism and translation, suggesting these cells have low metabolic activity. Biofilm-upregulated genes included those whose products were predicted to be at the cell envelope, involved in regulating a stress response, and surprisingly, genes related to formation of the flagellar apparatus. Scanning electron microscopy visualized flagella that appeared to be a component of the biofilm matrix, supported by the observation that an aflagellated mutant displayed a less robust biofilm with no apparent filaments. We observed flagella in the biofilm matrix of additional H. pylori strains, supporting that flagellar use is widespread. Our data thus support a model in which H. pylori biofilm involves a multigene stress-biased response and that flagella play an important role in H. pylori biofilm formation.IMPORTANCE Biofilms, communities of bacteria that are embedded in a hydrated matrix of extracellular polymeric substances, pose a substantial health risk and are key contributors to many chronic and recurrent infections. Chronicity and recalcitrant infections are also common features associated with the ulcer-causing human pathogen H. pylori However, relatively little is known about the role of biofilms in H. pylori pathogenesis, as well as the biofilm structure itself and the genes associated with this mode of growth. In the present study, we found that H. pylori biofilm cells highly expressed genes related to cell envelope and stress response, as well as those encoding the flagellar apparatus. Flagellar filaments were seen in high abundance in the biofilm. Flagella are known to play a role in initial biofilm formation, but typically are downregulated after that state. H. pylori instead appears to have coopted these structures for nonmotility roles, including a role building a robust biofilm.},
}
@article {pmid30377199,
year = {2018},
author = {Ealand, C and Rimal, B and Chang, J and Mashigo, L and Chengalroyen, M and Mapela, L and Beukes, G and Machowski, E and Kim, SJ and Kana, B},
title = {Erratum for Ealand et al., &quot;Resuscitation-Promoting Factors Are Required for Mycobacterium smegmatis Biofilm Formation&quot;.},
journal = {Applied and environmental microbiology},
volume = {84},
number = {22},
pages = {},
doi = {10.1128/AEM.02179-18},
pmid = {30377199},
issn = {1098-5336},
}
@article {pmid30376953,
year = {2018},
author = {Carniello, V and Peterson, BW and van der Mei, HC and Busscher, HJ},
title = {Physico-chemistry from initial bacterial adhesion to surface-programmed biofilm growth.},
journal = {Advances in colloid and interface science},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.cis.2018.10.005},
pmid = {30376953},
issn = {1873-3727},
abstract = {Biofilm formation is initiated by adhesion of individual bacteria to a surface. However, surface adhesion alone is not sufficient to form the complex community architecture of a biofilm. Surface-sensing creates bacterial awareness of their adhering state on the surface and is essential to initiate the phenotypic and genotypic changes that characterize the transition from initial bacterial adhesion to a biofilm. Physico-chemistry has been frequently applied to explain initial bacterial adhesion phenomena, including bacterial mass transport, role of substratum surface properties in initial adhesion and the transition from reversible to irreversible adhesion. However, also emergent biofilm properties, such as production of extracellular-polymeric-substances (EPS), can be surface-programmed. This review presents a four-step, comprehensive description of the role of physico-chemistry from initial bacterial adhesion to surface-programmed biofilm growth: (1) bacterial mass transport towards a surface, (2) reversible bacterial adhesion and (3) transition to irreversible adhesion and (4) cell wall deformation and associated emergent properties. Bacterial transport mostly occurs from sedimentation or convective-diffusion, while initial bacterial adhesion can be described by surface thermodynamic and Derjaguin-Landau-Verwey-Overbeek (DLVO)-analyses, considering bacteria as smooth, inert colloidal particles. DLVO-analyses however, require precise indication of the bacterial cell surface, which is impossible due to the presence of bacterial surface tethers, creating a multi-scale roughness that impedes proper definition of the interaction distance in DLVO-analyses. Application of surface thermodynamics is also difficult, because initial bacterial adhesion is only an equilibrium phenomenon for a short period of time, when bacteria are attached to a substratum surface through few surface tethers. Physico-chemical bond-strengthening occurs in several minutes leading to irreversible adhesion due to progressive removal of interfacial water, conformational changes in cell surface proteins, re-orientation of bacteria on a surface and the progressive involvement of more tethers in adhesion. After initial bond-strengthening, adhesion forces arising from a substratum surface cause nanoscopic deformation of the bacterial cell wall against the elasticity of the rigid peptidoglycan layer positioned in the cell wall and the intracellular pressure of the cytoplasm. Cell wall deformation not only increases the contact area with a substratum surface, presenting another physico-chemical bond-strengthening mechanism, but is also accompanied by membrane surface tension changes. Membrane-located sensor molecules subsequently react to control emergent phenotypic and genotypic properties in biofilms, most notably adhesion-associated ones like EPS production. Moreover, also bacterial efflux pump systems may be activated or mechano-sensitive channels may be opened upon adhesion-induced cell wall deformation. The physico-chemical properties of the substratum surface thus control the response of initially adhering bacteria and through excretion of autoinducer molecules extend the awareness of their adhering state to other biofilm inhabitants who subsequently respond with similar emergent properties. Herewith, physico-chemistry is not only involved in initial bacterial adhesion to surfaces but also in what we here propose to call &quot;surface-programmed&quot; biofilm growth. This conclusion is pivotal for the development of new strategies to control biofilm formation on substratum surfaces, that have hitherto been largely confined to the initial bacterial adhesion phenomena.},
}
@article {pmid30376123,
year = {2018},
author = {Naderi, J and Giles, C and Saboohi, S and Griesser, HJ and Coad, BR},
title = {Surface coatings with covalently attached anidulafungin and micafungin prevent Candida albicans biofilm formation.},
journal = {The Journal of antimicrobial chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1093/jac/dky437},
pmid = {30376123},
issn = {1460-2091},
abstract = {Objectives: Fungal biofilms caused by Candida spp. are a major contributor to infections originating from infected biomaterial implants. Since echinocandin-class molecules interfere with the integrity of the fungal cell wall, it was hypothesized that surface-immobilized anidulafungin and micafungin could play a role in preventing fungal adhesion and biofilm formation on surfaces.<br><br>Methods: Anidulafungin and micafungin were covalently coupled to biomaterial surfaces and washed. Surface-sensitive instrumental analysis quantitatively and qualitatively confirmed their presence. Analysis after washing experiments provided evidence of their covalent immobilization. The in vitro antifungal properties of surfaces were confirmed using static biofilm assays and fluorescence microscopy kinetic studies.<br><br>Results: Antifungal surface coatings eliminated 106 cfu/cm2 inoculations of Candida albicans and prevented biofilm formation and hyphal development on coated surfaces. Surfaces were successively exposed to fresh inoculum and were effective for at least five challenges in eliminating adherent yeasts.<br><br>Conclusions: We have observed antifungal and anti-biofilm activity of surfaces bearing conjugated echinocandins, which operate through surface contact. The analytical and biological evidence suggests an antifungal mechanism for echinocandins that does not rely upon freely diffusing molecules.},
}
@article {pmid30375445,
year = {2018},
author = {Shang, L and Deng, D and Buskermolen, JK and Janus, MM and Krom, BP and Roffel, S and Waaijman, T and van Loveren, C and Crielaard, W and Gibbs, S},
title = {Multi-species oral biofilm promotes reconstructed human gingiva epithelial barrier function.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {16061},
doi = {10.1038/s41598-018-34390-y},
pmid = {30375445},
issn = {2045-2322},
abstract = {Since the oral mucosa is continuously exposed to abundant microbes, one of its most important defense features is a highly proliferative, thick, stratified epithelium. The cellular mechanisms responsible for this are still unknown. The aim of this study was to determine whether multi-species oral biofilm contribute to the extensive stratification and primed antimicrobial defense in epithelium. Two in vitro models were used: 3D reconstructed human gingiva (RHG) and oral bacteria representative of multi-species commensal biofilm. The organotypic RHG consists of a reconstructed stratified gingiva epithelium on a gingiva fibroblast populated hydrogel (lamina propria). Biofilm was cultured from healthy human saliva, and consists of typical commensal genera Granulicatella and major oral microbiota genera Veillonella and Streptococcus. Biofilm was applied topically to RHG and host-microbiome interactions were studied over 7 days. Compared to unexposed RHG, biofilm exposed RHG showed increased epithelial thickness, more organized stratification and increased keratinocyte proliferation. Furthermore biofilm exposure increased production of RHG anti-microbial proteins Elafin, HBD2 and HBD3 but not HBD1, adrenomedullin or cathelicidin LL-37. Inflammatory and antimicrobial cytokine secretion (IL-6, CXCL8, CXCL1, CCL20) showed an immediate and sustained increase. In conclusion, exposure of RHG to commensal oral biofilm actively contributes to RHG epithelial barrier function.},
}
@article {pmid30374340,
year = {2018},
author = {Tuohy, JM and Mueller-Spitz, SR and Albert, CM and Scholz-Ng, SE and Wall, ME and Noutsios, GT and Gutierrez, AJ and Sandrin, TR},
title = {MALDI-TOF MS Affords Discrimination of Deinococcus aquaticus Isolates Obtained From Diverse Biofilm Habitats.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {2442},
doi = {10.3389/fmicb.2018.02442},
pmid = {30374340},
issn = {1664-302X},
abstract = {Matrix-assisted Laser Desorption Ionization-Time of Flight Mass Spectroscopy (MALDI-TOF MS) has been used routinely over the past decade in clinical microbiology laboratories to rapidly characterize diverse microorganisms of medical importance both at the genus and species levels. Currently, there is keen interest in applying MALDI-TOF MS at taxonomic levels beyond species and to characterize environmental isolates. We constructed a model system consisting of 19 isolates of Deinococcus aquaticus obtained from biofilm communities indigenous to diverse substrates (concrete, leaf tissue, metal, and wood) in the Fox River - Lake Winnebago system of Wisconsin to: (1) develop rapid sample preparation methods that produce high quality, reproducible MALDI-TOF spectra and (2) compare the performance of MALDI-TOF MS-based profiling to common DNA-based approaches including 16S rRNA sequencing and genomic diversity by BOX-A1R fingerprinting. Our results suggest that MALDI-TOF MS can be used to rapidly and reproducibly characterize environmental isolates of D. aquaticus at the subpopulation level. MALDI-TOF MS provided higher taxonomic resolution than either 16S rRNA gene sequence analysis or BOX-A1R fingerprinting. Spectra contained features that appeared to permit characterization of isolates into two co-occurring subpopulations. However, reliable strain-level performance required rigorous and systematic standardization of culture conditions and sample preparation. Our work suggests that MALDI-TOF MS offers promise as a rapid, reproducible, and high-resolution approach to characterize environmental isolates of members of the genus Deinococcus. Future work will focus upon application of methods described here to additional members of this ecologically diverse and ubiquitous genus.},
}
@article {pmid30370437,
year = {2018},
author = {Balato, G and Roscetto, E and Vollaro, A and Galasso, O and Gasparini, G and Ascione, T and Catania, MR and Mariconda, M},
title = {Bacterial biofilm formation is variably inhibited by different formulations of antibiotic-loaded bone cement in vitro.},
journal = {Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00167-018-5230-x},
pmid = {30370437},
issn = {1433-7347},
abstract = {PURPOSE: The aim of the present study was to quantitatively assess biofilm growth on the surface of bone cements discs containing different antibiotics, including colistin and linezolid. Biofilms of methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Staphylococcus epidermidis were grown on bone cement discs for 96 h.<br><br>METHODS: Biofilm amounts were measured by confocal laser microscopy using live/dead staining and dedicated software at different time intervals (48, 72, and 96 h).<br><br>RESULTS: Bone cement containing vancomycin was not effective at reducing MRSA biofilm formation 96 h following bacterial inoculation. At a comparable time interval, linezolid-, clindamycin-, and aminoglycoside-loaded cement was still active against this biofilm. At the 72- and 96-h observations, S. epidermidis biofilm was present only on tobramycin and gentamicin discs. P. aeruginosa biofilms were present on cement discs loaded with colistin at all time intervals starting from the 48-h observation, whereas no biofilms were detected on tobramycin or gentamicin discs.<br><br>CONCLUSION: Bone cements containing different antibiotics have variable and time-dependent windows of activity in inhibiting or reducing surface biofilm formation. The effectiveness of bone cement containing vancomycin against MRSA biofilm is questionable. The present study is clinically relevant, because it suggests that adding the right antibiotic to bone cement could be a promising approach to treat periprosthetic infections. Indeed, the antibiofilm activity of different antibiotic-loaded bone cements could be preoperatively assessed using the current methodology in two-stage exchange procedures.},
}
@article {pmid30369909,
year = {2018},
author = {Korany, AM and Hua, Z and Green, T and Hanrahan, I and El-Shinawy, SH and El-Kholy, A and Hassan, G and Zhu, MJ},
title = {Efficacy of Ozonated Water, Chlorine, Chlorine Dioxide, Quaternary Ammonium Compounds and Peroxyacetic Acid Against Listeria monocytogenes Biofilm on Polystyrene Surfaces.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {2296},
doi = {10.3389/fmicb.2018.02296},
pmid = {30369909},
issn = {1664-302X},
abstract = {Listeria monocytogenes contaminated processing equipment and the general packing environment have been implicated in deadly foodborne listeriosis outbreaks, highlighting the significance of proper sanitization and disinfection of food contact surfaces. This study aims to comprehensively evaluate antimicrobial efficacy of commercially available, economical sanitizers at practical concentrations against L. monocytogenes biofilm formed on polystyrene surfaces under different conditions. Ozonated water 1-min treatment at 1.0, 2.0, and 4.0 ppm resulted in ∼0.9, 3.4, and 4.1 log reduction of L. monocytogenes single strain biofilm grown on polystyrene surfaces, respectively. However, its efficacy was dramatically diminished in multi-strain L. monocytogenes biofilm and was further compromised by aged biofilm and in the presence of organic matter. Quaternary ammonium compounds (QAC) at 100/400 ppm, chlorine at 100/200 ppm, chlorine dioxide at 2.5/5.0 ppm and peroxyacetic acid (PAA) at 80/160 ppm resulted in 2.4/3.6, 2.0/3.1, 2.4/3.8, and 3.6/4.8 log reduction of L. monocytogenes single strain biofilm, respectively. Antimicrobial efficacies of all tested sanitizers against 7-day-old biofilm were much lower when compared to 2-day-old biofilm, with PAA being the least influenced by the age of the biofilm. Organic matter conditioning with diluted milk or apple juice dramatically impacted the antimicrobial efficacy of all sanitizers. PAA treatment of 1 min at 160-200 ppm resulted in a 3.2-3.5 log reduction against 7-day-old biofilm in the presence of organic matter, thus showing its effectiveness in eradicating L. monocytogenes biofilm on polystyrene surface. Collectively, data highlight the importance of timely and thoroughly cleaning food contact surfaces before disinfection and provides practical information and guidance for the food industry in selecting the most effective sanitizer in their sanitizing regimes to eliminate L. monocytogenes biofilm.},
}
@article {pmid30368924,
year = {2018},
author = {Yan, J and Moreau, A and Khodaparast, S and Perazzo, A and Feng, J and Fei, C and Mao, S and Mukherjee, S and Košmrlj, A and Wingreen, NS and Bassler, BL and Stone, HA},
title = {Bacterial Biofilm Material Properties Enable Removal and Transfer by Capillary Peeling.},
journal = {Advanced materials (Deerfield Beach, Fla.)},
volume = {},
number = {},
pages = {e1804153},
doi = {10.1002/adma.201804153},
pmid = {30368924},
issn = {1521-4095},
support = {//Howard Hughes Medical Institute/ ; MCB-1713731//NSF/ ; MCB-1344191//NSF/ ; //Max Planck Society-Alexander von Humboldt Foundation/ ; //Burroughs Wellcome Fund/ ; //Life Sciences Research Foundation Postdoctoral Fellowship/ ; GBMF2550.06//Gordon and Betty Moore Foundation/ ; },
abstract = {Biofilms, surface-attached communities of bacterial cells, are a concern in health and in industrial operations because of persistent infections, clogging of flows, and surface fouling. Extracellular matrices provide mechanical protection to biofilm-dwelling cells as well as protection from chemical insults, including antibiotics. Understanding how biofilm material properties arise from constituent matrix components and how these properties change in different environments is crucial for designing biofilm removal strategies. Here, using rheological characterization and surface analyses of Vibrio cholerae biofilms, it is discovered how extracellular polysaccharides, proteins, and cells function together to define biofilm mechanical and interfacial properties. Using insight gained from our measurements, a facile capillary peeling technology is developed to remove biofilms from surfaces or to transfer intact biofilms from one surface to another. It is shown that the findings are applicable to other biofilm-forming bacterial species and to multiple surfaces. Thus, the technology and the understanding that have been developed could potentially be employed to characterize and/or treat biofilm-related infections and industrial biofouling problems.},
}
@article {pmid30368608,
year = {2018},
author = {Mahdinia, E and Demirci, A and Berenjian, A},
title = {Effects of medium components in a glycerol-based medium on vitamin K (menaquinone-7) production by Bacillus subtilis natto in biofilm reactors.},
journal = {Bioprocess and biosystems engineering},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00449-018-2027-8},
pmid = {30368608},
issn = {1615-7605},
support = {Project PEN04561 and Accession number 1002249//USDA National Institute of Food and Agriculture Federal Appropriations/ ; },
abstract = {Menaquinone-7 (MK-7) as the most important form of Vitamin K has been reported to have miraculous benefits such as preventing cardiovascular diseases and osteoporosis along with antitumor effects. Therefore, there have been numerous studies in the past decades to improve MK-7 production via microbial fermentation. Unfortunately, both solid and liquid state fermentation strategies that are utilized for MK-7 production, face fundamental operational and scale-up issues as well as intense heat and mass transfer problems during fermentation. In this regard, biofilm reactors seem to be a practical solution to overcome these issues and enhance the production in agitated liquid fermentation. Therefore, this study was undertaken to utilize biofilm reactors in investigating and optimizing different media components in a glycerol-based medium. Using response surface methodology, the effects of glycerol, yeast extract, and soytone were studied in the fermentation medium on MK-7 production in biofilm reactor. With a composition of 48.2 g/L of glycerol, 8.1 g/L of yeast extracts, 13.6 g/L of soytone and 0.06 g/L of K2HPO4, MK-7 concentrations could reach 14.7 ± 1.4 mg/L in biofilm reactors, which was 57% higher compared to the MK-7 concentration achieved in suspended-cell reactors under similar conditions, while glycerol was depleted by the end of the fifth day in biofilm reactors, but glycerol was never depleted in suspended-cell reactors. Evidently, biofilm reactors present a reliable strategy to address the operational issues that occur during MK-7 biosynthesis on an industrial scale production.},
}
@article {pmid30368594,
year = {2018},
author = {Irankhah, S and Abdi Ali, A and Reza Soudi, M and Gharavi, S and Ayati, B},
title = {Highly efficient phenol degradation in a batch moving bed biofilm reactor: benefiting from biofilm-enhancing bacteria.},
journal = {World journal of microbiology &amp; biotechnology},
volume = {34},
number = {11},
pages = {164},
doi = {10.1007/s11274-018-2543-3},
pmid = {30368594},
issn = {1573-0972},
support = {96001722//National Foundation for Science and Technology Development/ ; },
abstract = {In this study, the efficiency improvement of three moving bed biofilm reactors (MBBRs) was investigated by inoculation of activated sludge cells (R1), mixed culture of eight strong phenol-degrading bacteria consisted of Pseudomonas spp. and Acinetobacter spp. (R2) and the combination of both (R3). Biofilm formation ability of eight bacteria was assessed initially using different methods and media. Maximum degradation of phenol, COD, biomass growth and also changes in organic loading shock were used as parameters to measure the performance of reactors. According to the results, all eight strains were determined as enhanced biofilm forming bacteria (EBFB). Under optimum operating conditions, more than 90% of initial COD load of 2795 mg L-1 was reduced at 24 HRT in R3 while this reduction efficiency was observed in concentrations of 1290 mg L-1 and 1935 mg L-1, in R1 and R2, respectively. When encountering phenol loading shock-twice greater than optimum amount-R1, R2 and R3 managed to return to the steady-state condition within 32, 24 and 18 days, respectively. SEM microscopy and biomass growth measurements confirmed the contribution of more cells to biofilm formation in R3 followed by R2. Additionally, established biofilm in R3 was more resistant to phenol loading shock which can be attributed to the enhancer role of EBFB strains in this reactor. It has been demonstrated that the bacteria with both biofilm-forming and contaminant-degrading abilities are not only able to promote the immobilization of other favorable activated sludge cells in biofilm structure, but also cooperate in contaminant degradation which all consequently lead to improvement of treatment efficiency.},
}
@article {pmid30368202,
year = {2018},
author = {Naumova, EA and Weber, L and Pankratz, V and Czenskowski, V and Arnold, WH},
title = {Bacterial viability in oral biofilm after tooth brushing with amine fluoride or sodium fluoride.},
journal = {Archives of oral biology},
volume = {97},
number = {},
pages = {91-96},
doi = {10.1016/j.archoralbio.2018.10.013},
pmid = {30368202},
issn = {1879-1506},
abstract = {OBJECTIVE: The aim of this study was to investigate the effects of sodium fluoride (NaF) and amine fluoride (AmF) on bacterial viability in the oral cavity.<br><br>MATERIAL AND METHODS: Healthy subjects brushed their teeth with either fluoride free toothpaste, NaF- or AmF-containing toothpaste. Biofilm smears from different locations were collected before and immediately and 30 and 120 min after tooth brushing. The smears were stained with live/dead bacterial staining, and the number of the respective bacteria was counted. The data were statistically analyzed by comparing the numbers of bacteria before and after the application of no fluoride, NaF and AmF.<br><br>RESULTS: The highest numbers of bacteria were found in the tongue biofilm, followed by the palatal and cheek biofilm. The lowest numbers were found in the mouth floor biofilm. After the application of AmF, no changes in the numbers of bacteria were found in the biofilms, except for the cheek, where they were reduced. After the application of NaF, the number of bacteria decreased significantly in all biofilms. After 120 min, bacterial regrowth was complete.<br><br>CONCLUSIONS: AmF has only little effect on the bacterial viability of oral biofilms. NaF application reduces the number of living bacteria in the oral biofilms. This effect lasts not longer than 120 min.},
}
@article {pmid30366999,
year = {2018},
author = {Kharadi, RR and Castiblanco, LF and Waters, CM and Sundin, GW},
title = {Phosphodiesterase genes regulate amylovoran production, biofilm formation, and virulence in Erwinia amylovora.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.02233-18},
pmid = {30366999},
issn = {1098-5336},
abstract = {Cyclic di-GMP (c-di-GMP) is a ubiquitous bacterial second messenger molecule that is an important virulence regulator in the plant pathogen Erwinia amylovora Intracellular levels of c-di-GMP are modulated by diguanylate cyclase (DGC) enzymes that synthesize c-di-GMP and phosphodiesterase (PDE) enzymes that degrade c-di-GMP. The regulatory role of the PDE enzymes in E. amylovora has not been determined. Using a combination of single, double, and triple deletion mutants, we determined the effect of each of the four putative PDE-encoding genes (pdeA, pdeB, pdeC, and edcA) in E. amylovora on cellular processes related to virulence. Our results indicate that pdeA and pdeC are the two most active phosphodiesterases in virulence regulation in E. amylovora Ea1189. The deletion of pdeC resulted in a measurably significant increase in the intracellular pool of c-di-GMP, and the highest intracellular concentrations of c-di-GMP were observed in the Ea1189ΔpdeAC and Ea1189ΔpdeABC mutants. The regulation of virulence traits due to the deletion of the pde genes showed two patterns. A stronger regulatory effect was observed on amylovoran production and biofilm formation, where both Ea1189ΔpdeA and Ea1189ΔpdeC exhibited a significant increase in these two phenotypes in vitro In contrast, the deletion of two or more pde genes was required to affect motility and virulence phenotypes. Our results indicate a functional redundancy among the pde genes in E. amylovora for certain traits and indicate that the intracellular degradation of c-di-GMP is mainly regulated by pdeA and pdeC, but also suggest a role for pdeB in regulating motility and virulence.IMPORTANCE Precise control of the expression of virulence genes is essential for successful infection of apple hosts by the fire blight pathogen Erwinia amylovora The presence and buildup of a signaling molecule called cyclic di-GMP enables the expression and function of some virulence determinants in E. amylovora such as amylovoran production and biofilm formation. However, other determinants, such as motility and the type III secretion system are expressed and functional when cyclic di-GMP is absent. In this manuscript, we report studies of enzymes called phosphodiesterases that function in the degradation of cyclic di-GMP. We show the importance of these enzymes in virulence gene regulation and the ability of E. amylovora to cause plant disease.},
}
@article {pmid30366231,
year = {2018},
author = {Rago, L and Zecchin, S and Villa, F and Goglio, A and Corsini, A and Cavalca, L and Schievano, A},
title = {Bioelectrochemical Nitrogen fixation (e-BNF): Electro-stimulation of enriched biofilm communities drives autotrophic nitrogen and carbon fixation.},
journal = {Bioelectrochemistry (Amsterdam, Netherlands)},
volume = {125},
number = {},
pages = {105-115},
doi = {10.1016/j.bioelechem.2018.10.002},
pmid = {30366231},
issn = {1878-562X},
abstract = {A new approach to microbial electrosynthesis is proposed, aimed at producing whole biomass from N2 and inorganic carbon, by electrostimulation of complex microbial communities. On a carbon-based conductor under constant polarization (-0.7 V vs SHE), an electroactive biofilm was enriched with autotrophic nitrogen fixing microorganims and led to biomass synthesis at higher amounts (up to 18 fold), as compared to controls kept at open circuit (OC). After 110 days, the electron transfer had increased by 30-fold, as compared to abiotic conditions. Metagenomics evidenced Nif genes associated with autotrophs (both Archaea and Bacteria) only in polarized biofilms, but not in OC. With this first proof of concept experiment, we propose to call this promising field 'bioelectrochemical nitrogen fixation' (e-BNF): a possible way to 'power' biological nitrogen fixation, organic carbon storage and soil fertility against desertification, and possibly a new tool to study the development of early prokaryotic life in extreme environments.},
}
@article {pmid30365642,
year = {2018},
author = {Borges, KRA and Pimentel, IV and Lucena, LCLDS and Silva, MACND and Monteiro, SG and Monteiro, CA and Nascimento, MDDSB and Bezerra, GFB},
title = {Adhesion and biofilm formation of Candida parapsilosis isolated from vaginal secretions to copper intrauterine devices.},
journal = {Revista do Instituto de Medicina Tropical de Sao Paulo},
volume = {60},
number = {},
pages = {e59},
doi = {10.1590/S1678-9946201860059},
pmid = {30365642},
issn = {1678-9946},
abstract = {INTRODUCTION: Candida parapsilosis is one of the main species that is able to adhere to forming biofilms on inert materials. Adhesion is the first step towards the colonization and invasion of host cells during the infectious process. Among the infections, vulvovaginal candidiasis is increasingly common. The objective was to evaluate the profile of adherence and biofilm formation of eight isolates of C. parapsilosis on the metal used in intrauterine devices (IUDs).<br><br>METHODS: Eight strains of C. parapsilosis presenting strong adhesion and biofilm formation properties were isolated from vaginal secretions in a previous study. To assay the adhesion and biofilm formation, copper fragments were made and cultivated in tubes containing 3 mL of phosphate-buffered saline and incubated for 6 and 24 h at 37 °C to evaluate biofilm formation. After incubation, the intensity of adherence and of biofilm formation on copper fragments were determined by performing a colony count.<br><br>RESULTS: All isolates were able to form biofilms and the isolate Cp62 showed many cells joined in a planktonic mode forming biofilms. The use of an IUD is one of the main factors that favors vulvovaginal candidiasis, and the presence of copper in this device increases the chance of recurrent vulvovaginal candidiasis (CVVR) due to the ease with which species of the genus Candida can adhere to inert surfaces.<br><br>CONCLUSION: This research showed that the clinical isolates studied adhered to IUD copper fragments and formed biofilms, further increasing their virulence.},
}
@article {pmid30364807,
year = {2018},
author = {Midha, A and Janek, K and Niewienda, A and Henklein, P and Guenther, S and Serra, DO and Schlosser, J and Hengge, R and Hartmann, S},
title = {Corrigendum: The Intestinal Roundworm Ascaris suum Releases Antimicrobial Factors Which Interfere With Bacterial Growth and Biofilm Formation.},
journal = {Frontiers in cellular and infection microbiology},
volume = {8},
number = {},
pages = {367},
doi = {10.3389/fcimb.2018.00367},
pmid = {30364807},
issn = {2235-2988},
abstract = {[This corrects the article DOI: 10.3389/fcimb.2018.00271.].},
}
@article {pmid30363861,
year = {2018},
author = {Farkash, Y and Feldman, M and Ginsburg, I and Steinberg, D and Shalish, M},
title = {Green Tea Polyphenols and Padma Hepaten Inhibit Candida albicans Biofilm Formation.},
journal = {Evidence-based complementary and alternative medicine : eCAM},
volume = {2018},
number = {},
pages = {1690747},
doi = {10.1155/2018/1690747},
pmid = {30363861},
issn = {1741-427X},
abstract = {Candida albicans (C. albicans) is the most prevalent opportunistic human pathogenic fungus and can cause mucosal membrane infections and invade the blood. In the oral cavity, it can ferment dietary sugars, produce organic acids and therefore has a role in caries development. In this study, we examined whether the polyphenol rich extractions Polyphenon from green tea (PPFGT) and Padma Hepaten (PH) can inhibit the caries-inducing properties of C. albicans. Biofilms of C. albicans were grown in the presence of PPFGT and PH. Formation of biofilms was tested spectrophotometrically after crystal violet staining. Exopolysaccharides (EPS) secretion was quantified using confocal scanning laser microscopy (CSLM). Treated C. albicans morphology was demonstrated using scanning electron microscopy (SEM). Expression of virulence-related genes was tested using qRT-PCR. Development of biofilm was also tested on an orthodontic surface (Essix) to assess biofilm inhibition ability on such appliances. Both PPFGT and PH dose-dependently inhibited biofilm formation, with no inhibition on planktonic growth. The strongest inhibition was obtained using the combination of the substances. Crystal violet staining showed a significant reduction of 45% in biofilm formation using a concentration of 2.5mg/ml PPFGT and 0.16mg/ml PH. A concentration of 1.25 mg/ml PPFGT and 0.16 mg/ml PH inhibited candidal growth by 88% and EPS secretion by 74% according to CSLM. A reduction in biofilm formation and in the transition from yeast to hyphal morphotype was observed using SEM. A strong reduction was found in the expression of hwp1, eap1, and als3 virulence associated genes. These results demonstrate the inhibitory effect of natural PPFGT polyphenolic extraction on C. albicans biofilm formation and EPS secretion, alone and together with PH. In an era of increased drug resistance, the use of phytomedicine to constrain biofilm development, without killing host cells, may pave the way to a novel therapeutic concept, especially in children as orthodontic patients.},
}
@article {pmid30361978,
year = {2018},
author = {Kim, SK and Li, XH and Hwang, HJ and Lee, JH},
title = {Antibiofilm effect of biofilm-dispersing agents on clinical isolates of Pseudomonas aeruginosa with various biofilm structures.},
journal = {Journal of microbiology (Seoul, Korea)},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12275-018-8336-4},
pmid = {30361978},
issn = {1976-3794},
abstract = {Pseudomonas aeruginosa, an opportunistic human pathogen, causes many biofilm-mediated chronic infections. In this study, biofilm structures of various clinical strains of P. aeruginosa isolated from hospitalized patients were examined and their influence on the biofilm-dispersing effects of chemicals was investigated. The clinical isolates formed structurally distinct biofilms that could be classified into three different groups: 1) mushroom-like, 2) thin flat, and 3) thick flat structures. A dispersion of these differently structured biofilms was induced using two biofilm-dispersing agents, anthranilate and sodium nitroprusside (SNP). Although both SNP and anthranilate could disperse all types of biofilms, the thick flat biofilms were dispersed less efficiently than the biofilms of other structures. This suggests that biofilm-dispersing agents have higher potency on the biofilms of porous structures than on densely packed biofilms.},
}
@article {pmid30360241,
year = {2019},
author = {Song, Z and Zhang, X and Ngo, HH and Guo, W and Song, P and Zhang, Y and Wen, H and Guo, J},
title = {Zeolite powder based polyurethane sponges as biocarriers in moving bed biofilm reactor for improving nitrogen removal of municipal wastewater.},
journal = {The Science of the total environment},
volume = {651},
number = {Pt 1},
pages = {1078-1086},
doi = {10.1016/j.scitotenv.2018.09.173},
pmid = {30360241},
issn = {1879-1026},
abstract = {This study aims to enhance nitrogen removal efficiency of a moving bed biofilm reactor (MBBR) by developing a new MBBR with zeolite powder-based polyurethane sponges as biocarriers (Z-MBBR). Results indicated the total nitrogen (TN) removal efficiency and simultaneous nitrification and denitrification (SND) performance in Z-MBBR were nearly 10% higher than those in the conventional MBBR with sponges as biocarriers (S-MBBR). About 84.2 ± 4.8% of TN was removed in Z-MBBR compared to 75.1 ± 6.8% in S-MBBR. Correspondingly, the SND performance in Z-MBBR and S-MBBR was 90.7 ± 4.1% and 81.7 ± 6.5%, respectively. The amount of biofilm attached to new biocarriers (0.470 ± 0.131 g/g carrier) was 1.3 times more than that of sponge carriers (0.355 ± 0.099 g/g carrier). Based on the microelectrode measurements and microbial community analysis, more denitrifying bacteria existed in the Z-MBBR system, and this can improve the SND performance. Consequently, this new Z-MBBR can be a promising option for a hybrid treatment system to better nitrogen removal from wastewater.},
}
@article {pmid30357538,
year = {2018},
author = {Cao, W and Zhang, Y and Wang, X and Li, Q and Xiao, Y and Li, P and Wang, L and Ye, Z and Xing, X},
title = {Novel resin-based dental material with anti-biofilm activity and improved mechanical property by incorporating hydrophilic cationic copolymer functionalized nanodiamond.},
journal = {Journal of materials science. Materials in medicine},
volume = {29},
number = {11},
pages = {162},
doi = {10.1007/s10856-018-6172-z},
pmid = {30357538},
issn = {1573-4838},
support = {No. 81460107//the Natural Science Foundation of China/ ; },
abstract = {There is an increasing clinical need to design dental restorative materials that combine excellent mechanical property and anti-biofilm activity. In the current study, photocurable polycation functionalized nanodiamond (QND) was synthesized and proposed as novel filler for dental resins. By reason of increased repulsive force between nanoparticles and enhanced compatibility with resin matrix, QND dispersed uniformly in reinforced resins, which would help to transfer stress and deformation from the matrix to fillers more efficiently, resulting in a significant improvement in mechanical properties. Notably, the Vickers's hardness, flexural strength and flexural modulus of resins containing 1.0 wt% QND were 44.5, 36.1 and 41.3% higher than that of control, respectively. The antibacterial activity against Streptococcus mutans (S. mutans) showed that QND-incorporated resins produced anti-adhesive property due to their hydrophilic surfaces and could suppress bacterial growth as a result of the contact-killing effect of embedded nanocomposites. As the synergistic effect of anti-adhesive and bactericidal performance, resins loading 1.0~1.5 wt% QNDs displayed excellent anti-biofilm activity. Meanwhile, the results of macrophage cytotoxicity showed that the proliferation of RAW 264.7 cells remained 84.3%, even at a concentration of 1.0 wt% QNDs after 7-day incubation. Therefore, the QND-containing dental resin with the combination of high mechanical property, bacteria-repellent capability and antibacterial performance holds great potential as a restorative material based on this scheme.},
}
@article {pmid30357139,
year = {2018},
author = {Parandhaman, T and Das, SK},
title = {Facile synthesis, biofilm disruption properties and biocompatibility study of a poly-cationic peptide functionalized graphene-silver nanocomposite.},
journal = {Biomaterials science},
volume = {},
number = {},
pages = {},
doi = {10.1039/c8bm01003j},
pmid = {30357139},
issn = {2047-4849},
abstract = {Bacterial colonization and biofilm formation is a growing challenge in the biomedical field. Although nanotechnology has emerged as an alternative strategy to combat biofilm formation, the toxicity of nanomaterials is a major concern. In this study, we report a safe-by-design strategy for the synthesis of a poly-cationic peptide functionalized graphene-silver nanocomposite (designated as GAPP) and its enhanced biofilm inhibition and disruption properties to eliminate the biofilm development of Gram-negative bacteria. The graphene-silver (rGOAg) nanocomposite was synthesized by microwave reduction, and subsequently functionalized with an antimicrobial poly-cationic peptide through covalent bonding. The results demonstrated that GAPP effectively killed the planktonic cells and biofilms of Escherichia coli and Pseudomonas aeruginosa depending upon the concentration and duration of the interaction. The complete eradication of preformed biofilm was achieved when treated with 10 μg mL-1 of GAPP for 5 h. The GAPP exerted bactericidal and biofilm inhibition activity through a &quot;contact-kill-release&quot; mode of action, wherein the electrostatic interaction of GAPP with the bacterial cells induced physical disruption accompanied by ROS-mediated biochemical changes. The internalization of GAPP into the cytoplasm through the damaged membrane led to metabolic imbalance in the cells. The peptide functionalization further prevented the dissolution of Ag+ ions, thus minimizing the cytotoxicity of GAPP to adult zebrafish. More importantly, the poly-cationic peptide functionalization enhanced the bioavailability, biofilm inhibition and disruption activities of GAPP, while minimizing its toxicological impact. The results obtained thereby provide an effective strategy in the design of alternative antibacterial agents for fighting biofilms of Gram-negative bacteria.},
}
@article {pmid30356998,
year = {2018},
author = {Yu, L and Shang, F and Chen, X and Ni, J and Yu, L and Zhang, M and Sun, D and Xue, T},
title = {The anti-biofilm effect of silver-nanoparticle-decorated quercetin nanoparticles on a multi-drug resistant Escherichia coli strain isolated from a dairy cow with mastitis.},
journal = {PeerJ},
volume = {6},
number = {},
pages = {e5711},
doi = {10.7717/peerj.5711},
pmid = {30356998},
issn = {2167-8359},
abstract = {Background: Escherichia coli is an important opportunistic pathogen that could cause inflammation of the udder in dairy cows resulting in reduced milk production and changes in milk composition and quality, and even death of dairy cows. Therefore, mastitis is the main health issue which leads to major economic losses on dairy farms. Antibiotics are routinely used for the treatment of bovine mastitis. The ability to form biofilm increases the antibiotic resistance of E. coli. Nanoparticles (NPs), a nanosized, safe, and highly cost-effective antibacterial agent, are potential biomedical tools. Given their antibacterial activities, silver nanoparticles (Ag NPs) have a broad range of applications.<br><br>Methods: In this study, we performed antibacterial activity assays, biofilm formation assays, scanning electron microscopy (SEM) experiments, and real-time reverse transcription PCR (RT-PCR) experiments to investigate the antibacterial and anti-biofilm effect of quercetin, Ag NPs, and Silver-nanoparticle-decorated quercetin nanoparticles (QA NPs) in E. coli strain ECDCM1.<br><br>Results: In this study, QA NPs, a composite material combining Ag NPs and the plant-derived drug component quercetin, exhibited stronger antibacterial and anti-biofilm properties in a multi-drug resistant E. coli strain isolated from a dairy cow with mastitis, compared to Ag NPs and Qe.<br><br>Discussion: This study provides evidence that QA NPs possess high antibacterial and anti-biofilm activities. They proved to be more effective than Ag NPs and Qe against the biofilm formation of a multi-drug resistant E. coli isolated from cows with mastitis. This suggests that QA NPs might be used as a potential antimicrobial agent in the treatment of bovine mastitis caused by E. coli.},
}
@article {pmid30356392,
year = {2018},
author = {Takesh, T and Ho, J and Firmalino, MV and Islip, D and Anbarani, A and Wilder-Smith, P},
title = {Effects of a Novel Formulation on Oral Biofilm, pH Buffering, and Gingival Health in Patients with Dry Mouth.},
journal = {International journal of dentistry},
volume = {2018},
number = {},
pages = {2748274},
doi = {10.1155/2018/2748274},
pmid = {30356392},
issn = {1687-8728},
abstract = {Goal: To identify in patients with dry mouth the effects of a novel test agent (Oral Essentials Hydrating Formula Mouthwash, Beverly Hills, CA) versus a control agent (Biotène Dry Mouth Oral Rinse, GlaxoSmithKline Consumer Healthcare L.P., Moon Township, PA, USA) versus no treatment on dry mouth, plaque, salivary pH and buffering capacity, gingival health, and tooth sensitivity.<br><br>Materials and Methods: In this cross-over study, ten subjects with dry mouth used test and control dry mouth interventions, as well as no dry mouth intervention in randomized sequence. Plaque Index, Gingival Index, Sulcus Bleeding Index, Plaque staining, and photographs were recorded at baseline and end of each study arm. Salivary volume, pH, and buffering capacity were also recorded at these time points. Additionally, subjects completed a questionnaire for dry mouth and dentinal sensitivity at each visit.<br><br>Results: Reductions in plaque presence and clinical indices were similar after use of test or control products (p < 0.05). Saliva volume and pH buffering improved significantly after use of test and control products (p < 0.05).<br><br>Conclusions: The effects of a novel dry mouth intervention are similar to those of an existing OTC remedy and are significantly better than no intervention.},
}
@article {pmid30355991,
year = {2018},
author = {Zhang, Y and Xia, B and Li, M and Shi, J and Long, Y and Jin, Y and Bai, F and Cheng, Z and Jin, S and Wu, W},
title = {HigB Reciprocally Controls Biofilm Formation and the Expression of Type III Secretion System Genes through Influencing the Intracellular c-di-GMP Level in Pseudomonas aeruginosa.},
journal = {Toxins},
volume = {10},
number = {11},
pages = {},
doi = {10.3390/toxins10110424},
pmid = {30355991},
issn = {2072-6651},
support = {41831287, 31670130, and 31600110//National Science Foundation of China/ ; 2018JZ0069//Science and Technology Program of Sichuan Province/ ; 15JCYBJC53900 and 15JCZDJC33000//Science and Technology Committee of Tianjin/ ; },
abstract = {Toxin-antitoxin (TA) systems play important roles in bacteria persister formation. Increasing evidence demonstrate the roles of TA systems in regulating virulence factors in pathogenic bacteria. The toxin HigB in Pseudomonas aeruginosa contributes to persister formation and regulates the expression of multiple virulence factors and biofilm formation. However, the regulatory mechanism remains elusive. In this study, we explored the HigB mediated regulatory pathways. We demonstrate that HigB decreases the intracellular level of c-di-GMP, which is responsible for the increased expression of the type III secretion system (T3SS) genes and repression of biofilm formation. By analyzing the expression levels of the known c-di-GMP metabolism genes, we find that three c-di-GMP hydrolysis genes are up regulated by HigB, namely PA2133, PA2200 and PA3825. Deletion of the three genes individually or simultaneously diminishes the HigB mediated regulation on the expression of T3SS genes and biofilm formation. Therefore, our results reveal novel functions of HigB in P. aeruginosa.},
}
@article {pmid30355820,
year = {2018},
author = {Georgiev, KG and Filipov, IA and Dobrev, IN},
title = {In Vivo Collection and SEM Identification of Oral Biofilm Using Indirect Composite Prototype Restorations. Clinical and Laboratory Study.},
journal = {Folia medica},
volume = {60},
number = {2},
pages = {300-307},
doi = {10.1515/folmed-2017-0092},
pmid = {30355820},
issn = {0204-8043},
abstract = {BACKGROUND: The oral ecosystem is a dynamic environment inhabited by more than 700 microbial taxa. Recent studies report that multispecies oral biofilms develop on the surface of resin composites leading to degradation of its organic matrix and altered structural stability of the restoration.<br><br>AIM: To examine the efficacy of a novel clinical approach to investigating in vivo formed biofilms on resin composite surfaces.<br><br>MATERIALS AND METHODS: The clinical protocol of this study implemented indirect composite molar restorations (from resin material Filtek Z250, 3M ESPE) as intraoral biofilm carriers (test devices). We recruited for the experiment 5 consenting adult subjects with indications for indirect molar restoration. For each subject we fabricated 4 indirect restorations, 3 of which dedicated to different intraoral duration - 3, 7, and 14 days. All composite carriers were fixed temporarily for the intended time period and consecutively replaced. The detached carriers were prepared for microscope analysis at each time interval. The fourth composite carrier was used as the definitive restoration.<br><br>RESULTS: The timeline of the biofilm formation and the microbial morphology were associated with previous studies of in vivo bacterial colonisation. A correlation between the plaque formation cycle and the DMFt indices of the subjects was established.<br><br>CONCLUSIONS: The implementation of indirect composite restorations as intraoral biofilm carrier offers valuable contribution to the real time investigation of in vivo biofilm accumulation.},
}
@article {pmid30354689,
year = {2018},
author = {Mello, TP and Oliveira, SSC and Frasés, S and Branquinha, MH and Santos, ALS},
title = {Surface properties, adhesion and biofilm formation on different surfaces by Scedosporium spp. and Lomentospora prolificans.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-15},
doi = {10.1080/08927014.2018.1503652},
pmid = {30354689},
issn = {1029-2454},
abstract = {In the present work, some surface properties of the fungi Scedosporium apiospermum, S. aurantiacum, S. minutisporum, and Lomentospora prolificans and their capability to adhere to and form a biofilm on diverse surfaces were evaluated. All four species had high conidial surface hydrophobicity and elevated electronegative zeta potentials. Abundant quantities of melanin were detected at the conidial surface, whereas sialic acid was absent. The numbers of non-germinated and germinated conidia adhered to poly-L-lysine-covered slides was higher than on glass after 4 h of fungi-surface contact. Additionally, after 72 h of interaction a typical biofilm structure had formed. Mature biofilms were also observed after 72 h on a nasogastric catheter (made from polyvinyl chloride), a late bladder catheter (siliconized latex), and a nasoenteric catheter (polyurethane). Interestingly, biofilm biomass increased considerably when the catheters had previously been incubated with serum. These results confirm that Scedosporium/Lomentospora spp. are capable of forming biofilms on diverse abiotic surfaces.},
}
@article {pmid30354082,
year = {2018},
author = {Zhang, N and Thompson, CEL and Townend, IH and Rankin, KE and Paterson, DM and Manning, AJ},
title = {Non-destructive 3D imaging and quantification of hydrated biofilm-sediment aggregates using X-ray micro-computed tomography.},
journal = {Environmental science &amp; technology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.est.8b03997},
pmid = {30354082},
issn = {1520-5851},
abstract = {Biofilm-sediment aggregate (BSA) contains a high water content, either within internal pores and channels, or bound by extracellular polymeric substances (EPS) forming a highly hydrated biofilm matrix. Desiccation of BSAs alters the biofilm morphology and thus the physical characteristics of porous media, such as the binding matrix within BSA and internal pore geometry. Observing BSAs in their naturally hydrated form is essential but hampered due to the lack of techniques for imaging and discerning hydrated materials. Generally, imagery techniques (scanning electron microscopy (SEM), transmission electron microscopy (TEM) and focused ion beam nano-tomography (FIB-nt)) involve the desiccation of BSAs (freeze-drying or acetone dehydration), or prevents differentiation between BSA components such as inorganic particles and pore water (confocal laser scanning microscopic (CLSM)). Here, we propose a novel methodology that simultaneously achieves the 3D visualization and quantification of BSAs and their components in their hydrated form at a sub-micron scale using X-ray micro-computed tomography (µ-CT). It enables the high-resolution detection of comparable morphology of multi-phase components within a hydrated aggregate: each single inorganic particle and the hydrated biofilm matrix. This allows the estimation of aggregate density and the illustration of biofilm-sediment binding matrix. This information provides valuable insights into investigations of the transport of BSAs and aggregate-associated sediment particles, contaminants (such as microplastics), organic carbon, and their impacts on aquatic biogeochemical cycling.},
}
@article {pmid30354054,
year = {2018},
author = {Mei, Y and Yu, K and Lo, JCY and Takeuchi, LE and Hadjesfandiari, N and Yazdani-Ahmadabadi, H and Brooks, DE and Lange, D and Kizhakkedathu, JN},
title = {Polymer-Nanoparticle Interaction as a Design Principle in the Development of a Durable Ultra-Thin Universal Binary Anti-Biofilm Coating with Long-Term Activity.},
journal = {ACS nano},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsnano.8b05512},
pmid = {30354054},
issn = {1936-086X},
abstract = {Bacterial attachment and biofilm formation pose major challenges to the optimal performance of indwelling devices. Current coating methods have significant deficiencies including the lack of long-term activity, easy of application and adaptability to diverse materials. Here we describe a coating method that could potentially overcome such limitations, and yield an ultra-thin coating with long-term antibiofilm activity. We utilized the interaction between polydopamine (PDA) nanoaggregates/nanoparticles and ultra-high molecular weight (uHMW) hydrophilic polymers to generate stable coatings with broad spectrum antibiofilm activity. We used a short-term bacterial adhesion assay as an initial screening method to identify coating compositions that give superior performance and found that only selected polymers (out of 13 different types) and molecular weights gave promising antifouling activity. Optimization of PDA self-assembly, polymer-PDA interaction and deposition on the surface using uHMW poly(N,N-dimethylacrylamide) (PDMA) (~795 KDa) resulted in a stable ultrathin coating (~19 nm) with excellent antifouling and antibiofilm properties (>4 weeks) against diverse bacteria (~100000000 CFU/ml) in shaking and flow conditions. The ultra-thin coating is effective on diverse substrates including metals and polymeric substrates. The uHMW PDMA is stabilized in the coating via supramolecular interactions with PDA, and generated a surface that is highly enriched with PDMA in aqueous conditions. Based on the surface analyses data, we also propose a mechanism for the stable coating formation. The molecular weight of PDMA is a crucial factor and only uHMW polymers generate this property. An attractive feature of the coating is that it does not contain any antimicrobial agents, and has the potential to prevent biofilm formation for diverse applications both short- and long-term.},
}
@article {pmid30352435,
year = {2018},
author = {Wijesinghe, G and Dilhari, A and Gayani, B and Kottegoda, N and Samaranayake, LP and Weerasekera, M},
title = {Influence of Laboratory Culture Media on In-vitro Growth, Adhesion and Biofilm Formation of Pseudomonas aeruginosa and Staphylococcus aureus.},
journal = {Medical principles and practice : international journal of the Kuwait University, Health Science Centre},
volume = {},
number = {},
pages = {},
doi = {10.1159/000494757},
pmid = {30352435},
issn = {1423-0151},
abstract = {OBJECTIVE: Pseudomonas aeruginosa and Staphylococcus aureus dual species biofilm infections are notoriously difficult to manage. This study was aimed at investigating the influence of four different culture media on the planktonic growth, adhesion and biofilm formation of Pseudomonas aeruginosa and Staphylococcus aureus.<br><br>MATERIALS AND METHODS: We monitored four different culture media including Nutrient broth (NB), Brain Heart Infusion (BHI) broth, Luria-Bertani (LB) broth and RPMI 1640 medium on the planktonic growth, adhesion and biofilm formation of Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923) using MTT assay and scanning electron microscopy (SEM).<br><br>RESULTS: The most robust growth of the mono and dual species cultures was noted in BHI broth. On the contrary, RPMI 1640 medium promoted maximal initial adhesion of both the mono and dual species but BHI broth fostered the maximal biofilm growth. SEM images showed profuse extracellular polysaccharide production in biofilms particularly in co-culture, in BHI medium.<br><br>CONCLUSION: Our data demonstrate that BHI broth, relative to other tested media, is the most conducive for in vitro evaluation of biofilm and planktonic growth kinetics of these two pathogens, both in mono- and co-culture.},
}
@article {pmid30352266,
year = {2018},
author = {Muthuraman, MS and Nithya, S and Vinoth Kumar, V and Christena, LR and Vadivel, V and Subramanian, NS and Anthony, SP},
title = {Green synthesis of silver nanoparticles using Nardostachys jatamansi and evaluation of its anti-biofilm effect against classical colonizers.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2018.10.024},
pmid = {30352266},
issn = {1096-1208},
abstract = {In this communication, we present the green synthesis of silver nanoparticles (AgNPs) using medicinally important Nardostachys jatamansi rhizome extract in the presence of sunlight. UV-vis spectroscopy, Fourier Transform Infrared spectroscopy (FTIR), Transmission electron microscope (TEM) and Energy dispersive X-ray analysis (EDX) were employed to characterize the synthesized AgNPs. UV-visible spectroscopic studies confirmed the presence of biosynthesized AgNPs. Transmission Electron Microscopic studies revealed the structure of spherical AgNPs in the diameter range of 10-15 nm. Energy dispersive X-ray analysis and elemental mapping clearly confirmed the presence of silver in AgNPs samples. Interestingly, biomolecules functionalised AgNPs exhibited a remarkable antioxidant, anti-inflammatory, and anti-biofilm activities and hence biosynthesized AgNPs from N. jatamansi can be used as a promising biomaterial for biomedical applications.},
}
@article {pmid30351033,
year = {2018},
author = {Aggarwal, S and Gomez-Smith, CK and Jeon, Y and LaPara, TM and Waak, M and Hozalski, RM},
title = {Effects of Chloramine and Coupon Material on Biofilm Abundance and Community Composition in Bench-Scale Simulated Water Distribution Systems and Comparison with Full-Scale Water Mains.},
journal = {Environmental science &amp; technology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.est.8b02607},
pmid = {30351033},
issn = {1520-5851},
abstract = {The vast majority of bacteria in drinking water distribution systems (DWDSs) reside in biofilms on the interior walls of water mains. Little is known about how water quality conditions affect water-main biofilms because of the inherent limitations in experimenting with drinking water supplies and accessing the water mains for sampling. Bench-scale reactors permit experimentation and ease of biofilm sampling, yet questions remain as to how well biofilms in laboratory reactors represent those on water mains. In this study, the effects of DWDS pipe materials and chloramine residual on biofilms were investigated by cultivating biofilms on cement, polyvinyl chloride and high density polyethylene coupons in CDC reactors for up to 28 months in the presence of chloraminated or dechlorinated tap water. The bench-scale biofilm microbiomes were then compared with the microbiome on a water main from the full-scale system that supplied the water to the reactors. The presence of a chloramine residual (1.74 ± 0.21 mg/L) suppressed biofilm accumulation and selected for Mycobacteria-like and Sphingopyxis-like operational taxonomic units (OTUs) while the destruction of the chloramine residual resulted in a significant increase in biomass quantity and a shift toward a more diverse community dominated by Nitrospira-like OTUs, which, our results suggest, may be complete ammonia oxidizers (comammox). Coupon material, however, had a relatively minor effect on the abundance and community composition of the biofilm bacteria. Although biofilm communities from the chloraminated water reactor and the water mains shared some dominant populations (namely, Mycobacteria- and Nitrosomonas-like OTUs), the communities were significantly different. This manuscript provides novel insights into the effects of dechlorination and pipe material on biofilm community composition. Furthermore, to our knowledge, it is the first study to compare biofilm in a tap water-fed, bench-scale simulated distribution system to biofilm on water mains from the full-scale system supplying the tap water.},
}
@article {pmid30350807,
year = {2018},
author = {Nirwati, H and Hakim, MS and Darma, S and Mustafa, M and Nuryastuti, T},
title = {Detection of blaoxa genes and identification of biofilm-producing capacity of Acinetobacter baumannii in a tertiary teaching hospital, Klaten, Indonesia.},
journal = {The Medical journal of Malaysia},
volume = {73},
number = {5},
pages = {291-296},
pmid = {30350807},
issn = {0300-5283},
abstract = {INTRODUCTION: Acinetobacter baumannii (A. baumannii) is commonly found as an agent of nosocomial infections and demonstrates a high antibiotic resistance due to its carbapenemase production. The objectives of this study were to explore the antibiotic resistance pattern, the presence of OXAs genes and the biofilm-producing capacity of A. baumannii isolated from clinical specimens.<br><br>METHODS: Antibiotics susceptibility testing, detection of OXAs genes and the biofilm-producing capacity were performed using the Kirby Bauer method, polymerase chain reaction (PCR) and adherence quantitative assays, respectively.<br><br>RESULTS: A total of 80 A. baumannii isolates were mainly obtained from sputum and most of them were resistant to antibiotics. All A. baumannii carried blaOXA-51 gene, yet no blaOXA-24 and blaOXA-58 genes were detected. Fourteen (82.4%) of the 17 meropenem resistant isolates carried blaOXA-23 gene, but it was not found in meropenem sensitive isolates. In addition, sixty (75.0%) of 80 isolates were biofilm producers with 2 (2.5%), 16 (20.0%), and 42 (52.5%) isolates were identified as strong, moderate and weak biofilm producers, respectively.<br><br>CONCLUSION: Most of A. baumannii isolates had a high level of antibiotic resistance and had a capacity to produce biofilm.},
}
@article {pmid30350577,
year = {2018},
author = {Skorb, EV and Nikitina, AA and Ulasevich, SA and Kassirov, IS and Bryushkova, EA and Koshel, EI},
title = {Nanostructured Layer-by-Layer Polyelectrolyte Containers to Switch Biofilm Fluorescence.},
journal = {Bioconjugate chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.bioconjchem.8b00648},
pmid = {30350577},
issn = {1520-4812},
abstract = {The development of stimuli-responsive nanocontainers is an issue of prime importance for many applications such as target drug delivery, regulation of the cell and tissue's behavior, make bacteria do useful functions, here convert light. The present work shows a new contribution to the design of polyelectrolyte (PE) containers based on surface modified mesoporous titania particles with deposited Ag nanoparticles to have chemical light upconversion via biofilms. The PE shell allows to slow down the kinetics of a release of loaded L-arabinose and switch the bacteria luminescence in a certain time. The hybrid TiO2/Ag/PE containers activated at 980 nm (IR) illumination reveal 10 times faster release of L-arabinose vs non-activated containers. Fast IR-released L-arabinose switch bacteria fluorescence which we monitor at 510 nm. The approach described herein can be used in many applications where the target and delayed switching and light upconversion is required.},
}
@article {pmid30347401,
year = {2018},
author = {Yamada, KJ and Kielian, T},
title = {Biofilm-Leukocyte Cross-Talk: Impact on Immune Polarization and Immunometabolism.},
journal = {Journal of innate immunity},
volume = {},
number = {},
pages = {1-9},
doi = {10.1159/000492680},
pmid = {30347401},
issn = {1662-8128},
abstract = {Biofilms are bacterial communities contained within an extracellular matrix, which can colonize both native tissues and artificial surfaces. In particular, indwelling medical devices and prosthetic implants are targets for biofilm formation because they facilitate bacterial attachment via host proteins that coat the foreign body. Biofilm infections are particularly challenging to treat, since they are not readily cleared by antibiotics, require invasive procedures to eradicate, and are prone to recurrence. It has been demonstrated that biofilm-derived products can actively suppress proinflammatory immune responses, as evident by the recruitment of myeloid-derived suppressor cells and macrophage (MФ) polarization towards an anti-inflammatory state. Recent studies have shown that alterations in leukocyte metabolism shape their inflammatory phenotype and function. For example, anti-inflammatory MФs are biased towards oxidative phosphorylation whereas proinflammatory MФs favor aerobic glycolysis. This review will compare the immune responses elicited by planktonic and biofilm bacterial infections, with a discussion on the metabolic properties of MФs and neutrophils in response to both bacterial growth conditions.},
}
@article {pmid30347328,
year = {2018},
author = {Parrino, B and Schillaci, D and Carnevale, I and Giovannetti, E and Diana, P and Cirrincione, G and Cascioferro, S},
title = {Synthetic small molecules as anti-biofilm agents in the struggle against antibiotic resistance.},
journal = {European journal of medicinal chemistry},
volume = {161},
number = {},
pages = {154-178},
doi = {10.1016/j.ejmech.2018.10.036},
pmid = {30347328},
issn = {1768-3254},
abstract = {Biofilm formation significantly contributes to microbial survival in hostile environments and it is currently considered a key virulence factor for pathogens responsible for serious chronic infections. In the last decade many efforts have been made to identify new agents able to modulate bacterial biofilm life cycle, and many compounds have shown interesting activities in inhibiting biofilm formation or in dispersing pre-formed biofilms. However, only a few of these compounds were tested using in vivo models for their clinical significance. Contrary to conventional antibiotics, most of the anti-biofilm compounds act as anti-virulence agents as they do not affect bacterial growth. In this review we selected the most relevant literature of the last decade, focusing on the development of synthetic small molecules able to prevent bacterial biofilm formation or to eradicate pre-existing biofilms of clinically relevant Gram-positive and Gram-negative pathogens. In addition, we provide a comprehensive list of the possible targets to counteract biofilm formation and development, as well as a detailed discussion the advantages and disadvantages of the different current biofilm-targeting strategies.},
}
@article {pmid30345922,
year = {2018},
author = {Ciulla, M and Di Stefano, A and Marinelli, L and Cacciatore, I and Di Biase, G},
title = {RNAIII Inhibiting Peptide (RIP) and Derivatives as Potential Tools for the Treatment of S. aureus Biofilm Infections.},
journal = {Current topics in medicinal chemistry},
volume = {},
number = {},
pages = {},
doi = {10.2174/1568026618666181022120711},
pmid = {30345922},
issn = {1873-4294},
abstract = {S. aureus under biofilm mode of growth is often related to several nosocomial infections, more frequently associated with indwelling medical devices (catheters, prostheses, portacaths or heart valves). As a biofilm, the biopolymer matrix provides an excellent growth medium, increasing the tolerance to antibiotics and host immune system. To date, the antimicrobial therapy alone is not effective. A novel strategy to prevent biofilm formation is based on the interference with the bacterial cell-cell communication, a process known as quorum sensing (QS) and mediated by the RNA-III-activating peptide (RAP) and its target protein TRAP (Target of RAP). The RNAIII inhibiting peptide (RIP) is able to inhibit S. aureus pathogenesis by disrupting QS mechanism competing with RAP, thus inhibiting the phosphorylation of TRAP. This alteration leads to a reduced adhesion and to the inhibition of RNAIII synthesis, with the subsequent suppression of toxins synthesis. The present paper will provide an overview on the activity and potential applications of RIP as biofilm inhibiting compound, useful in the management of S. aureus biofilm infections. Moreover, medicinal chemistry strategies have been examined to better understand which modifications and/or structure alterations were able to produce new derivatives of this QS inhibitor with an improved antibiofilm activity.},
}
@article {pmid30345305,
year = {2018},
author = {Alcántar-Curiel, MD and Ledezma-Escalante, CA and Jarillo-Quijada, MD and Gayosso-Vázquez, C and Morfín-Otero, R and Rodríguez-Noriega, E and Cedillo-Ramírez, ML and Santos-Preciado, JI and Girón, JA},
title = {Association of Antibiotic Resistance, Cell Adherence, and Biofilm Production with the Endemicity of Nosocomial Klebsiella pneumoniae.},
journal = {BioMed research international},
volume = {2018},
number = {},
pages = {7012958},
doi = {10.1155/2018/7012958},
pmid = {30345305},
issn = {2314-6141},
abstract = {Klebsiella pneumoniae is a leading cause of multiple nosocomial infections, some of which are associated with high mortality. The increasing prevalence of antibiotic-resistant strains highlights their clinical importance and how complicated managing treatment can be. In this study, we investigated antimicrobial resistance, cell adherence, and biofilm production of nosocomial K. pneumoniae strains isolated from surveillance studies in a Mexican tertiary hospital and evaluated the potential association of these phenotypes with endemicity. The great majority of the clones exhibited adhesion to cultured epithelial cells and were strong biofilm producers. A direct relationship between adhesion phenotypes, biofilm production, and endemicity was not always apparent. Biofilm formation and production of ESBL did not appear to be directly associated. Notably, all the endemic strains were multidrug-resistant. This study emphasizes that while endemic strains possess various virulence-associated properties, antimicrobial resistance appears to be a determining factor of their endemicity.},
}
@article {pmid30342101,
year = {2018},
author = {Anju, VT and Paramanantham, P and Sruthil, SL and Sharan, A and Alsaedi, MH and Dawoud, TMS and Syed, A and Siddhardha, B},
title = {Antimicrobial photodynamic activity of rose bengal conjugated multi walled carbon nanotubes against planktonic cells and biofilm of Escherichia coli.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2018.10.013},
pmid = {30342101},
issn = {1873-1597},
abstract = {BACKGROUND: The global threat of antimicrobial resistance especially due to the bacterial biofilms has engaged researchers in the search of new treatment modalities. Antimicrobial photodynamic inactivation (aPDI) is one of the alternative treatment modalities which kills bacteria by generating endogenous ROS. In this work authors evaluated the antibacterial and antibiofilm efficacy of rose Bengal (RB) conjugated to CNT against E. coli.<br><br>METHODS: The interaction of anionic dye to the CNT was studied using UV-Visible spectroscopy, HR-TEM, FTIR and spectrofluorometry. Phototoxicity of RBCNT conjugate against E. coli was studied using a green light of 50 mW and radiant exposure of 1674.7 J/ cm2 for 10 minutes. The antibiofilm activity and mechanism of action of RBCNT conjugate in presence of light was evaluated.<br><br>RESULTS: The loading and encapsulation was found to be 15.46 ± 1.05 and 61.85 ± 4.23 % respectively. The photodynamic inactivation of planktonic cells of E. coli was found to 5.46 and 3.56 log10 reduction on treatment with RBCNT and RB respectively. The conjugate also exhibited efficient and enhanced antibiofilm activity against E. coli. The study of mechanism of action has confirmed cell membrane and DNA damage were the two main targets of aPDI.<br><br>CONCLUSION: This report has concluded the efficient photodynamic inactivation occurred in Gram negative bacteria E. coli due to the increased production of reactive oxygen species inside the bacterial cells. Hence, the newly synthesized RBCNT conjugate can be efficiently utilized to control infections caused by E. coli.},
}
@article {pmid30341934,
year = {2018},
author = {Allyn, G and Bloebaum, RD and Epperson, RT and Nielsen, MB and Dodd, KA and Williams, DL},
title = {Ability of a Wash Regimen to Remove Biofilm from the Exposed Surface of Materials Used in Osseointegrated Implants.},
journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society},
volume = {},
number = {},
pages = {},
doi = {10.1002/jor.24161},
pmid = {30341934},
issn = {1554-527X},
abstract = {The skin/implant interface of osseointegrated (OI) implants is susceptible to infection, causing excess pain, increased morbidity, and possibly implant removal. Novel distal femoral OI implants with binary nitride coatings have been developed with little physiological modeling to collect microbiological evidence of resistance to bacterial attachment. This in vitro study evaluated a Ti-6Al-4V alloy coated with TiNbN and treated with low plasticity burnishing (LPB) to assess attachment and biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA) under physiologically-modeling conditions compared to standard Ti-6Al-4V alloy materials with a polished (&quot;Color Buff&quot;) or non-polished finish (&quot;Satin Finish&quot;). Washability of the materials were also assessed and compared. It was hypothesized that the TiNbN/LPB treatments would resist bacterial adhesion and biofilm formation to a greater degree than the other two materials, and have a higher degree of bacterial removal following a clinically-relevant wash regimen. Material types were exposed to a constant flow of broth containing MRSA and were analyzed using bacterial quantification, surface coverage analysis, and SEM imaging. Quantification data showed no difference in bacterial attachment amongst the varying material types both with and without the wash regimen. Surface coverage and SEM analysis confirmed results. The wash regimen led to an approximately 3 log10 reduction in bacteria for all material types. Though the results did not support the hypothesis that a TiNbN coating/LPB treatment might resist bacterial attachment/biofilm formation more than other alloys, or have less bacteria after cleaning, results did support the potential importance of a daily wound-hygiene regimen at the skin/implant interface of OI materials. This article is protected by copyright. All rights reserved.},
}
@article {pmid30341079,
year = {2018},
author = {Jiang, W and Wang, Y and Luo, J and Li, X and Zhou, X and Li, W and Zhang, L},
title = {Effects of antimicrobial peptide GH12 on the cariogenic properties and composition of a cariogenic multispecies biofilm.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.01423-18},
pmid = {30341079},
issn = {1098-5336},
abstract = {Dental caries is a biofilm-mediated disease that occurs when acidogenic/aciduric bacteria obtain an ecological advantage over commensal species. In previous studies, the effects of the antimicrobial peptide GH12 on planktonic bacteria and monospecies biofilms were confirmed. The objectives of this study were to investigate the effects of GH12 on a cariogenic multispecies biofilm and to preliminarily explain the mechanism. In this biofilm model, Streptococcus mutansATCC 70061 was the representative of cariogenic bacteria, while Streptococcus gordoniiATCC 35105 and Streptococcus sanguinis JCM 5708 were selected as healthy microbiota. The results showed that GH12 was more effective in suppressing S. mutans than the other two species with lower MIC and MBC among diverse type strains and clinical isolated strains. Therefore, GH12, at no more than 8 mg/L, was used to selectively suppress S. mutans in the multispecies biofilm. GH12 at 4 mg/L and 8 mg/L reduced the cariogenic properties of the multispecies biofilm in biofilm formation, glucan synthesis, and lactic acid production. In addition, GH12 suppressed S. mutans within the multispecies biofilm and changed the bacterial composition. Furthermore, 8 mg/L GH12 showed a selective bactericidal impact on S. mutans, and GH12 could promote hydrogen peroxide production in S. sanguinis and S. gordonii, which improved their ecological advantages. In conclusion, GH12 inhibited the cariogenic properties and changed the composition of the multispecies biofilm through a two-part mechanism by which GH12 directly suppressed the growth of S. mutans as well as enhanced the ecological competitiveness of S. sanguinis and S. gordoniiIMPORTANCE Dental caries is one of the most prevalent chronic infectious diseases worldwide with substantial economic and quality-of-life impacts. Streptococcus mutans has been considered to be the principal pathogen of dental caries. To combat dental caries, an antimicrobial peptide, GH12, was designed, and its antibacterial effects on planktonic S. mutans and the monospecies biofilm were confirmed. As etiological concepts of dental caries evolved to include micro-ecosystems, homeostasis between pathogenic and commensal bacteria, and selective action on cariogenic virulence have increasingly become the focus. The novelty of this research was to study the effects of the antimicrobial peptides on a controlled cariogenic multispecies biofilm model. It was also noteworthy that the role of an antimicrobial agent in regulating interspecific competition and composition shifts within this multispecies biofilm was investigated. With promising antibacterial and antibiofilm properties, the use of GH12 might be of importance in preventing and controlling caries and other dental infections.},
}
@article {pmid30340133,
year = {2018},
author = {Spennati, F and Mora, M and Tigini, V and La China, S and Di Gregorio, S and Gabriel, D and Munz, G},
title = {Removal of Quebracho and Tara tannins in fungal bioreactors: Performance and biofilm stability analysis.},
journal = {Journal of environmental management},
volume = {231},
number = {},
pages = {137-145},
doi = {10.1016/j.jenvman.2018.10.001},
pmid = {30340133},
issn = {1095-8630},
abstract = {Tannins are polyphenolic compounds produced by plants that are used in the vegetable tanning of leather at industrial scale. Quebracho tannin and Tara tannin are intensively used by the tanning industry and are two of the most recalcitrant compounds that can be found in tannery wastewaters. In this study two reactors fed with Quebracho tannin and Tara tannin, respectively, were inoculated with polyurethane foam cubes colonized with a fungal strain biofilm of Aspergillus tubingensis MUT 990. A stable biofilm was maintained in the reactor fed with Quebracho tannin during 180 days of operation. Instead, biofilm got detached from the foam cubes during the start-up of the reactor fed with Tara tannin and a bacterial-based suspended culture was developed and preserved along the operational period (226 days). Soluble chemical oxygen demand removals up to 53% and 90% and maximum elimination capacities of 9.1 g sCOD m-3 h-1 and 37.9 g sCOD m-3 h-1 of Quebracho and Tara tannins, respectively, were achieved in the reactors without the addition of co-substrates. Next generation sequencing analysis for bacteria and fungi showed that a fungal consortium was developed in the reactor fed with Quebracho tannin while fungi were outcompeted by bacteria in the reactor fed with Tara tannin. Furthermore, Quebracho and Tara tannins were successfully co-treated in a single reactor where both fungi and bacteria were preserved.},
}
@article {pmid30339767,
year = {2018},
author = {Farfán, M and Lártiga, N and Benavides, MB and Alegría-Morán, R and Salcedo, C and Sáenz, L and Lapierre, LL},
title = {&quot;Adhesion and invasion capacity to human epithelial cells and its relation to the presence of virulence genes, motility and biofilm formation of Campylobacter jejuni strains isolated from chicken and bovine&quot;.},
journal = {Canadian journal of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1139/cjm-2018-0503},
pmid = {30339767},
issn = {1480-3275},
abstract = {Campylobacter jejuni is a zoonotic pathogen transmitted through the &quot;farm to fork&quot; route. Outbreaks are associated with consumption of chicken meat, however, other sources as been described. Currently, there is not enough data comparing the virulence of strains isolated from these reservoirs. In our study we compared C. jejuni strains isolated from broiler chicken and dairy cattle through determining their ability to adhere to and invade in vitro human colonic epithelial cell line T84 with their motility, formation of biofilms, and presence of eight virulence genes. A Wilcoxon Rank Sum test was performed to establish the relationship between presence of the studied genes and cellular invasion and adhesion, as well as differences between animal species of origin of the isolate. A Spearman correlation was performed to assess the relationship between invasion and motility, along with invasion and biofilm generation. The virB11 gene was positively associated with the adherence capacity of the strains (mean difference = 0.21, p = 0.006), and strains isolated from chickens showed a significant difference for adherence compared with strains isolated from cattle (p = 0.0001). Our results indicate that strains of C. jejuni have a difference in their adherence capacity depending on the animal reservoir from which they came, with chicken isolates displaying higher virulence compared to dairy cattle isolates.},
}
@article {pmid30338995,
year = {2018},
author = {Swasthi, HM and Bhasne, K and Mahapatra, S and Mukhopadhyay, S},
title = {Human Fibrinogen Inhibits Amyloid Assembly of Biofilm-Forming CsgA.},
journal = {Biochemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.biochem.8b00841},
pmid = {30338995},
issn = {1520-4995},
abstract = {Curli is a biofilm-forming amyloid that is expressed on the surface of Gram-negative enteric bacteria such as E.coli and Salmonella spp. Curli is primarily composed of the major structural subunit, CsgA, and interacts with a wide range of human proteins that contribute to the bacterial virulence. The adsorption of curli onto the contact-phase proteins and fibrinogen result in a hypocoagulatory state. Using an array of biochemical and biophysical tools, we elucidated the molecular mechanism of interaction between human fibrinogen and CsgA. Our results revealed that sub-stoichiometric concentration of fibrinogen delays the onset of CsgA aggregation by inhibiting the early events of CsgA assembly. The presence of fibrinogen prevents the maturation of CsgA into fibrils and maintains the soluble state of CsgA. We also demonstrate that fibrinogen interacts more effectively with the disordered conformational state of CsgA than with the ordered β-rich state. Our study suggested that fibrinogen is an anti-curli protein and that the interplay of CsgA and fibrinogen might be a host defense mechanism against curli biogenesis, biofilm formation, bacterial colonization, and infection.},
}
@article {pmid30338681,
year = {2018},
author = {Dua, K and Gupta, G and Koteswara Rao, N and Bebawy, M},
title = {Nano-antibiotics: a novel approach in treating P. aeruginosa biofilm infections.},
journal = {Minerva medica},
volume = {109},
number = {5},
pages = {400},
doi = {10.23736/S0026-4806.18.05588-X},
pmid = {30338681},
issn = {1827-1669},
}
@article {pmid30337708,
year = {2018},
author = {Ch'ng, JH and Chong, KKL and Lam, LN and Wong, JJ and Kline, KA},
title = {Biofilm-associated infection by enterococci.},
journal = {Nature reviews. Microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41579-018-0107-z},
pmid = {30337708},
issn = {1740-1534},
abstract = {Enterococci are ubiquitous members of the human gut microbiota and frequent causes of biofilm-associated opportunistic infections. Enterococci cause 25% of all catheter-associated urinary tract infections, are frequently isolated in wounds and are increasingly found in infective endocarditis, and all of these infections are associated with biofilms. Enterococcal biofilms are intrinsically tolerant to antimicrobials and thus are a serious impediment for treating infections. In this Review, we describe the spatiotemporal development of enterococcal biofilms and the factors that promote or inhibit biofilm formation. We discuss how the environment, including the host and other co-colonizing microorganisms, affects biofilm development. Finally, we provide an overview of current and future interventions to limit enterococcal biofilm-associated infections. Overall, enterococcal biofilms remain a pressing clinical problem, and there is an urgent need to better understand their development and persistence and to identify novel treatments.},
}
@article {pmid30337052,
year = {2018},
author = {Kirstein, IV and Wichels, A and Krohne, G and Gerdts, G},
title = {Mature biofilm communities on synthetic polymers in seawater - Specific or general?.},
journal = {Marine environmental research},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.marenvres.2018.09.028},
pmid = {30337052},
issn = {1879-0291},
abstract = {To understand the ecological impacts of the &quot;Plastisphere&quot;, those microbes need to be identified that preferentially colonize and interact with synthetic polymer surfaces, as opposed to general surface colonizers. It was hypothesized that the microbial biofilm composition varies distinctly between different substrates. A long-term incubation experiment was conducted (15month) with nine different synthetic polymer films as substrate as well as glass using a natural seawater flow-through system. To identify colonizing microorganisms, 16S and 18SrRNA gene tag sequencing was performed. The microbial biofilms of these diverse artificial surfaces were visualized via scanning electron microscopy. Biofilm communities attached to synthetic polymers are distinct from glass associated biofilms; apparently a more general marine biofilm core community serves as shared core among all synthetic polymers rather than a specific synthetic polymer community. Nevertheless, characteristic and discriminatory taxa of significantly different biofilm communities were identified, indicating their specificity to a given substrate.},
}
@article {pmid30336397,
year = {2018},
author = {Saunders, LP and Bischoff, KM and Bowman, MJ and Leathers, TD},
title = {Inhibition of Lactobacillus biofilm growth in fuel ethanol fermentations by Bacillus.},
journal = {Bioresource technology},
volume = {272},
number = {},
pages = {156-161},
doi = {10.1016/j.biortech.2018.10.016},
pmid = {30336397},
issn = {1873-2976},
abstract = {Commercial fuel ethanol fermentations suffer from microbial contaminants, particularly species of Lactobacillus that may persist as antibiotic-resistant biofilms. In this study, culture supernatants from 54 strains of Bacillus known to produce lipopeptides were tested for inhibition of biofilm formation by Lactobacillus fermentum, L. plantarum, and L. brevis strains previously isolated as biofilm-forming contaminants of a commercial fuel ethanol facility. Eleven Bacillus strains inhibited biofilm formation by all three strains by at least 65% of controls. None of these strains inhibited Saccharomyces cerevisiae. Three strains also significantly inhibited planktonic cultures of Lactobacillus. Culture supernatants from B. nakamurai strain NRRL B-41091 were particularly effective. Inhibition was bacteriostatic rather than bacteriocidal, and appeared to be specific for strains of Lactobacillus. Furthermore, the inhibitor from B. nakamurai was shown to prevent stuck fermentations in a corn mash model fermentation system of S. cerevisiae contaminated with L. fermentum.},
}
@article {pmid30336067,
year = {2018},
author = {Shelud'ko, AV and Filip'echeva, YA and Telesheva, EM and Yevstigneyeva, SS and Petrova, LP and Katsy, EI},
title = {Restoration of polar-flagellum motility and biofilm-forming capacity in the mmsB1 mutant of the alphaproteobacterium Azospirillum brasilense Sp245 points to a new role for a homologue of 3-hydroxyisobutyrate dehydrogenase.},
journal = {Canadian journal of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1139/cjm-2018-0481},
pmid = {30336067},
issn = {1480-3275},
abstract = {Bacteria Azospirillum brasilense can swim and swarm owing to the rotation of a constitutive polar flagellum (Fla) and inducible lateral flagella, respectively. They also form biofilms on various interfaces. Experimental data on flagellar assembly and social behaviours in these bacteria are scarce. Here, for the first time, the chromosomal coding sequence mmsB1 for a homologue of 3-hydroxyisobutyrate dehydrogenase (protein accession nos. ADT80774 and E7CWE2) was shown to play a role in the assembly of motile Fla and in biofilm biomass accumulation. In the previously obtained mutant SK039 of A. brasilense Sp245, an Omegon-Km insertion in mmsB1 was concurrent with changes in cell-surface properties and with suppression of Fla assembly (partial) and Fla-dependent motility (complete). Here, the immotile leaky Fla- mutant SK039 was complemented with the expression vector pRK415-borne mmsB1 gene of Sp245. In the complemented mutant, the elevated relative cell hydrophobicity and changed relative membrane fluidity of SK039 returned to the wild-type levels; also, biofilm biomass accumulation increased and even reached Sp245's levels under nutritionally rich conditions. In strain SK039 (pRK415-mmsB1), the percentage of cells with Fla became significantly higher than in mutant SK039, and the Fla-driven swimming velocity was equal to that in strain Sp245.},
}
@article {pmid30335931,
year = {2018},
author = {Liu, T and Guo, Z and Zeng, Z and Guo, N and Lei, Y and Liu, T and Sun, S and Chang, X and Yin, Y and Wang, X},
title = {Marine Bacteria Provide Lasting Anti-Corrosion Activity for Steel via Biofilm-induced Mineralization.},
journal = {ACS applied materials &amp; interfaces},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsami.8b14991},
pmid = {30335931},
issn = {1944-8252},
abstract = {Steel corrosion is a global problem in marine engineering. Numerous inhibitory treatments have been applied to mitigate the degradation of metallic materials; however, they typically have a high cost and are not environmental-friendly. Here we present a novel and &quot;green&quot; approach for the protection of steel by a marine bacterium Pseudoalteromonas lipolytica. This approach protects steel from corrosion in seawater via the formation of a biofilm followed by the formation of an organic-inorganic hybrid film. The hybrid film is composed of multiple layers of calcite and bacterial extracellular polymeric substances, exhibiting high and stable barrier protection efficiency and further providing in situ self-healing activity. The process involving the key transition from biofilm to biomineralized film is essential for its lasting anti-corrosion activity, which overcomes the instability of biofilm protection on corrosion. Therefore, this study introduces a new perspective and an option for anticorrosion control in marine environments.},
}
@article {pmid30334338,
year = {2018},
author = {Wang, J and Song, M and Pan, J and Shen, X and Liu, W and Zhang, X and Li, H and Deng, X},
title = {Quercetin impairs Streptococcus pneumoniae biofilm formation by inhibiting sortase A activity.},
journal = {Journal of cellular and molecular medicine},
volume = {},
number = {},
pages = {},
doi = {10.1111/jcmm.13910},
pmid = {30334338},
issn = {1582-4934},
support = {2017YFD0501500//National Key R &amp; D Program of China/ ; 31602109//National Natural Science Foundation of China/ ; },
abstract = {Biofilm formation mediated by sortase A (srtA) is important for bacterial colonisation and resistance to antibiotics. Thus, the inhibitor of SrtA may represent a promising agent for bacterial infection. The structure of Streptococcus pneumoniae D39 srtA has been characterised by crystallisation. Site-directed mutagenesis was used for the determination of the key residues for the activity of S. pneumoniae D39 srtA. An effective srtA inhibitor, quercetin, and its mechanism was further identified using srtA activity inhibition assay and molecular modelling. In this study, the crystal structure of S. pneumoniae D39 srtA has been solved and shown to contain a unique domain B. Additionally, its transpeptidase activity was evaluated in vitro. Based on the structure, we identified Cys207 as the catalytic residue, with His141 and Arg215 serving as binding sites for the peptide substrate. We found that quercetin can specifically compete with the natural substrate, leading to a significant decrease in the catalytic activity of this enzyme. In cells co-cultured with this small molecule inhibitor, NanA cannot anchor to the cell wall effectively, and biofilm formation and biomass decrease significantly. Interestingly, when we supplemented cultures with sialic acid, a crucial signal for pneumococcal coloniation and the invasion of the host in the co-culture system, biofilm loss did not occur. This result indicates that quercetin inhibits biofilm formation by affecting sialic acid production. In conclusion, the inhibition of pneumococcal srtA by the small molecule quercetin offers a novel strategy for pneumococcal preventative therapy.},
}
@article {pmid30333962,
year = {2018},
author = {Fang, H and Liu, L and Zhang, Y and Yang, H and Yan, Y and Ding, X and Han, Y and Zhou, D and Yang, R},
title = {BfvR, an AraC-Family Regulator, Controls Biofilm Formation and pH6 Antigen Production in Opposite Ways in Yersinia pestis Biovar Microtus.},
journal = {Frontiers in cellular and infection microbiology},
volume = {8},
number = {},
pages = {347},
doi = {10.3389/fcimb.2018.00347},
pmid = {30333962},
issn = {2235-2988},
abstract = {Biofilm formation is critical for blocking flea foregut and hence for transmission of Y. pestis by flea biting. In this study, we identified the regulatory role of the AraC-family transcriptional regulator BfvR (YPO1737 in strain CO92) in biofilm formation and virulence of Yersinia pestis biovar Microtus. Crystal violet staining, Caenorhabditis elegans biofilm assay, colony morphology assay, intracellular c-di-GMP concentration determination, and BALB/c mice challenge were employed to reveal that BfvR enhanced Y. pestis biofilm formation while repressed its virulence in mice. Further molecular biological assays demonstrated that BfvR directly stimulated the expression of hmsHFRS, waaAE-coaD, and hmsCDE, which, in turn, affected the production of exopolysaccharide, LPS, and c-di-GMP, respectively. In addition, BfvR directly and indirectly repressed psaABC and psaEF transcription, respectively. We concluded that the modulation of biofilm- and virulence-related genes by BfvR led to increased biofilm formation and reduced virulence of Y. pestis biovar Microtus.},
}
@article {pmid30333795,
year = {2018},
author = {Lawrence, JR and Winkler, M and Neu, TR},
title = {Multi-Parameter Laser Imaging Reveals Complex Microscale Biofilm Matrix in a Thick (4,000 μm) Aerobic Methanol Oxidizing Community.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {2186},
doi = {10.3389/fmicb.2018.02186},
pmid = {30333795},
issn = {1664-302X},
abstract = {Although methanol has frequently been used as an inexpensive supplementary carbon source to support treatment processes, knowledge of the resultant microbial biofilms, their 3D architecture, microenvironments, exopolymer chemistry and populations remains limited. We supplied methanol as a supplementary carbon source to biofilms developing in rotating annular reactors. Analysis of circulation waters (1.0 l d-1) indicated that dissolved organic carbon was reduced by 25%, NO3-nitrogen by 95%, and total phosphorus by 70%. Analyses of populations using culture based techniques and fluorescence in situ hybridization indicated enrichment of nitrifiers, denitrifiers, and methylotrophic bacteria relative to reference biofilms not receiving methanol. The biofilms that developed were up to 4,000 μm thick. Staining with fluor conjugated lectins in combination with nucleic acid stains, revealed the presence of discrete bacterial cells inside complex globular polymeric structures. These structures were in turn surrounded by an interstitial polymer containing a variety of bacterial cell types. The globular structures bound FITC-conjugated lectins, from Canavalia ensiformis and Ulex europeaus. The FITC-lectin of Phaseolus vulgaris bound the surface of the globular structures and more generally within the matrix. Chemical analyses of the polymer paralleled the results of lectin analyses indicating that the dominant neutral sugars were glucose, galactose, mannose, rhamnose, with fucose and ribose as minor constituents. Amino sugars were not detected. Dual channel imaging with pH sensitive probes indicated that pH gradients from pH 4 to 7 occurred across the globular microcolonies. Critically for the maintenance of aerobic conditions throughout the thick biofilm it was extensively penetrated by a fine fissure network revealed by the location of fluorescent latex microbeads as detected by confocal laser scanning microscopy. Microelectrode studies confirmed the absence of any detectable Eh gradients within the biofilm. However, mobility of various size-fractionated fluorescent probes indicated that the basal region was only penetrated by the lowest molecular weight probes with a hydrated radius of 2.2 nm or less. These observations indicate the selection of a unique, thick (>4,000 μm) microbial community in which a self-organized architecture promotes the maintenance of optimal conditions and metabolism throughout the biofilm community.},
}
@article {pmid30332894,
year = {2018},
author = {Wojciech, J and Kamila, M and Wojciech, B},
title = {Investigation of the population dynamics within a Pseudomonas aeruginosa biofilm using a flow based biofilm model system and flow cytometric evaluation of cellular physiology.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-16},
doi = {10.1080/08927014.2018.1508569},
pmid = {30332894},
issn = {1029-2454},
abstract = {In this study a flow based biofilm model system was used to simulate the formation of Pseudomonas aeruginosa biofilms on a stainless steel surface. To investigate the complexity of biofilm-associated P. aeruginosa populations a combination of microscopic observations and flow cytometric analysis (FCM) was adopted. Biofilm-associated P. aeruginosa cells were evaluated (1) under optimal vs reduced nutrient-availability at the initial adhesion stage, and (2) irrespective of nutrient-availability within a mature biofilm. Microscopic estimation of the extent of attachment revealed more effective colonization upon optimal vs starvation conditions. FCM allowed an in situ evaluation of P. aeruginosa vitality, using cellular redox potential measurements to discriminate active, mid-active and non-active sub-populations. Samples from recently attached cells and mature biofilms showed significant differences in the percentages of bacterial cells from the defined sub-populations. The approach demonstrated that distribution of individual P. aeruginosa sub-populations was influenced by the stage of the biofilm life-cycle and nutrient availability.},
}
@article {pmid30329046,
year = {2018},
author = {Recacha, E and Machuca, J and Díaz-Díaz, S and García-Duque, A and Ramos-Guelfo, M and Docobo-Pérez, F and Blázquez, J and Pascual, A and Rodríguez-Martínez, JM},
title = {Suppression of the SOS response modifies spatiotemporal evolution, post-antibiotic effect, bacterial fitness and biofilm formation in quinolone-resistant Escherichia coli.},
journal = {The Journal of antimicrobial chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1093/jac/dky407},
pmid = {30329046},
issn = {1460-2091},
abstract = {Background: Suppression of the SOS response has been proposed as a therapeutic strategy for potentiating quinolones against susceptible, low-level quinolone-resistant (LLQR) and resistant Enterobacteriaceae.<br><br>Objectives: To monitor the functionality of the SOS response in the evolution towards clinical quinolone resistance and study its impact on the evolution of spatiotemporal resistance.<br><br>Methods: An isogenic collection of Escherichia coli (derived from the strain ATCC 25922) carrying combinations of chromosomally and plasmid-mediated quinolone resistance mechanisms (including susceptible, LLQR and resistant phenotypes) and exhibiting a spectrum of SOS activity was used. Relevant clinical parameters such as mutation rate, mutant prevention concentration (MPC), bacterial fitness, biofilm formation and post-antibiotic effect (PAE) were evaluated.<br><br>Results: Inactivating the SOS response (recA deletion) led to a decrease in mutation rate (∼103 fold) in LLQR compared with WT strains at ciprofloxacin concentrations of 1 mg/L (the EUCAST breakpoint for resistance) and 2.5 mg/L (Cmax), as well as a remarkable delay in the spatiotemporal evolution of quinolone resistance. For all strains, there was an 8-fold decrease in MPC in RecA-deficient strains, with values for LLQR strains decreasing below the Cmax of ciprofloxacin. Inactivation of the SOS response reduced competitive fitness by 33%-50%, biofilm production by 22%-80% and increased the PAE by ∼3-4 h at sub-MIC concentrations of ciprofloxacin.<br><br>Conclusions: Our data indicate that suppression of the SOS response affects key bacterial traits and is a promising strategy for reversing and tackling the evolution of antibiotic resistance in E. coli, including low-level and resistant phenotypes at therapeutic quinolone concentrations.},
}
@article {pmid30328144,
year = {2018},
author = {Li, Z and Behrens, AM and Ginat, N and Tzeng, SY and Lu, X and Sivan, S and Langer, R and Jaklenec, A},
title = {Biofilm-Inspired Encapsulation of Probiotics for the Treatment of Complex Infections.},
journal = {Advanced materials (Deerfield Beach, Fla.)},
volume = {},
number = {},
pages = {e1803925},
doi = {10.1002/adma.201803925},
pmid = {30328144},
issn = {1521-4095},
support = {//Janggen-Pöhn-Foundation/ ; //Beatrice Beck-Schimmer/ ; //Hans-Ruedi Gonzenbach/ ; },
abstract = {The emergence of antimicrobial resistance poses a major challenge to healthcare. Probiotics offer a potential alternative treatment method but are often incompatible with antibiotics themselves, diminishing their overall therapeutic utility. This work uses biofilm-inspired encapsulation of probiotics to confer temporary antibiotic protection and to enable the coadministration of probiotics and antibiotics. Probiotics are encapsulated within alginate, a crucial component of pseudomonas biofilms, based on a simple two-step alginate cross-linking procedure. Following exposure to the antibiotic tobramycin, the growth and metabolic activity of encapsulated probiotics are unaffected by tobramycin, and they show a four-log survival advantage over free probiotics. This results from tobramycin sequestration on the periphery of alginate beads which prevents its diffusion into the core but yet allows probiotic byproducts to diffuse outward. It is demonstrated that this approach using tobramycin combined with encapsulated probiotic has the ability to completely eradicate methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa in coculture, the two most widely implicated bacteria in chronic wounds.},
}
@article {pmid30326805,
year = {2018},
author = {Joe, H and Seo, YJ},
title = {A newly designed tympanostomy stent with TiO2 coating to reduce Pseudomonas aeruginosa biofilm formation.},
journal = {Journal of biomaterials applications},
volume = {33},
number = {4},
pages = {599-605},
doi = {10.1177/0885328218802103},
pmid = {30326805},
issn = {1530-8022},
abstract = {Biofilm formation has been implicated as a cause of post-tympanostomy tube otorrhea in patients suffering from otitis media with effusion, and biofilms have been found to adhere to all available types of tympanostomy tubes (TT) made from silicone. In this study, we present a novel stent designed with a reduced surface area and a titanium dioxide (TiO2) coating to prevent biofilm formation. Using a radio frequency power supply, tympanostomy stents (TS) made from Nitinol (Nikel-titanium) were coated with TiO2 to form an oxide layer on the metallic target. We successfully reproduced biofilms with carbenicillin-resistant Pseudomonas aeruginosa strain, PAO1-GFP (green fluorescent protein) on the tubes in vitro. We then compared the levels of biofilm formation by this strain on the two types of implants using several methods, including bacterial quantification, electron microscopy, and confocal laser fluorescent microscopy. Our results provide definitive evidence that the combination of the TiO2 coating and minimized surface area of the Nitinol stent inhibited the P. aeruginosa biofilm formation. The ability of the TS to prevent viable bacteria colonization (over 10 folds, compared to silicone TT) was verified by anti-biofilm test. Future studies will reveal more useful in reducing otorrhea and plugging complications as a novel tympanostomy tube.},
}
@article {pmid30325949,
year = {2018},
author = {Wongsaroj, L and Saninjuk, K and Romsang, A and Duang-Nkern, J and Trinachartvanit, W and Vattanaviboon, P and Mongkolsuk, S},
title = {Pseudomonas aeruginosa glutathione biosynthesis genes play multiple roles in stress protection, bacterial virulence and biofilm formation.},
journal = {PloS one},
volume = {13},
number = {10},
pages = {e0205815},
doi = {10.1371/journal.pone.0205815},
pmid = {30325949},
issn = {1932-6203},
abstract = {Pseudomonas aeruginosa PAO1 contains gshA and gshB genes, which encode enzymes involved in glutathione (GSH) biosynthesis. Challenging P. aeruginosa with hydrogen peroxide, cumene hydroperoxide, and t-butyl hydroperoxide increased the expression of gshA and gshB. The physiological roles of these genes in P. aeruginosa oxidative stress, bacterial virulence, and biofilm formation were examined using P. aeruginosa ΔgshA, ΔgshB, and double ΔgshAΔgshB mutant strains. These mutants exhibited significantly increased susceptibility to methyl viologen, thiol-depleting agent, and methylglyoxal compared to PAO1. Expression of functional gshA, gshB or exogenous supplementation with GSH complemented these phenotypes, which indicates that the observed mutant phenotypes arose from their inability to produce GSH. Virulence assays using a Drosophila melanogaster model revealed that the ΔgshA, ΔgshB and double ΔgshAΔgshB mutants exhibited attenuated virulence phenotypes. An analysis of virulence factors, including pyocyanin, pyoverdine, and cell motility (swimming and twitching), showed that these levels were reduced in these gsh mutants compared to PAO1. In contrast, biofilm formation increased in mutants. These data indicate that the GSH product and the genes responsible for GSH synthesis play multiple crucial roles in oxidative stress protection, bacterial virulence and biofilm formation in P. aeruginosa.},
}
@article {pmid30325394,
year = {2018},
author = {Liu, S and Cao, S and Guo, J and Luo, L and Zhou, Y and Lin, C and Shi, J and Fan, C and Lv, M and Wang, L},
title = {Graphene oxide-silver nanocomposites modulate biofilm formation and extracellular polymeric substance (EPS) production.},
journal = {Nanoscale},
volume = {},
number = {},
pages = {},
doi = {10.1039/c8nr04064h},
pmid = {30325394},
issn = {2040-3372},
abstract = {Biofilms with positive and negative actions ubiquitously affect medical infections, environmental remediation and industrial processes. However, it remains challenging to control the growth of harmful biofilms as well as to exploit the use of beneficial biofilms. Here we investigated the effect of an antibacterial graphene oxide-silver nanoparticles (GO-AgNPs) composite on Pseudomonas aeruginosa biofilm formation. We found that GO-AgNPs prevented biofilm formation in a dose-dependent manner, with a threshold of 15 μg mL-1. Interestingly, the bacterial biomass significantly decreased, but extracellular polymeric substance (EPS) production remarkably increased in mature biofilms treated with GO-AgNPs of an appropriate concentration, suggesting that GO-AgNPs effectively modulate biofilm development and structure. Moreover, we established that GO-AgNPs caused bacterial death via both physical damage and oxidative stress, showing the synergic action of GO and AgNPs. These findings facilitate the use of graphene-based nanocomposites for greener antibiotic applications.},
}
@article {pmid30325222,
year = {2018},
author = {Trmcic, A and Chen, H and Trząskowska, M and Tamber, S and Wang, S},
title = {Biofilm-Forming Capacity of Five Salmonella Strains and Their Fate on Postharvest Mini Cucumbers.},
journal = {Journal of food protection},
volume = {},
number = {},
pages = {1871-1879},
doi = {10.4315/0362-028X.JFP-18-180},
pmid = {30325222},
issn = {1944-9097},
abstract = {Salmonella enterica is one of the pathogens that is frequently identified as the cause of fresh produce-related outbreaks. Biofilm formation is a factor that can contribute to pathogen survival on produce surface. The goal of our current research was to investigate the survival of five S. enterica strains representing different serotypes (i.e., Typhimurium, Enteritidis, Daytona, Poona, and Newport) on whole mini cucumbers stored at refrigeration (4°C) and room temperature (22°C). We also determined the strains survival on glass slides and in phosphate-buffered saline at 4 and 22°C, as well as the ability to form biofilms on a solid-liquid interphase. A rapid decrease in cell density (>4-log reduction over 8 days) of all five tested strains was observed on glass slides, while a slower die-off (<1-log reduction in 8 days) was observed in PBS. No significant difference in the die-off rate was observed among the five strains at 4 or 22°C. The die-off rate on the surface of mini cucumbers at 4°C was significantly slower (P < 0.02) for Salmonella Enteritidis LMFS-S-JF-005 compared with the remaining four strains. At 22°C, Salmonella Poona S306 was able to grow by more than 1.5 log units on whole mini cucumbers over a period of 8 days, while the cell density of the other four strains remained at the same level compared with day 0. At this temperature, Salmonella Poona S306 was also able to form significantly stronger biofilms on a solid-liquid interphase (P < 0.01) and was the only strain that presented a red, dry, and rough morphotype on Congo red agar plates, indicating the formation of both curli fimbriae and cellulose. These results revealed that the fate of Salmonella on mini cucumbers is strain specific, which highlighted the need for tailored mitigation strategies, such as the effective control of temperature and moisture for limiting the survival or growth of high-risk Salmonella strains between harvest and consumption of fresh produce.},
}
@article {pmid30324376,
year = {2018},
author = {Xu, Y and Wang, C and Hou, J and Wang, P and You, G and Miao, L},
title = {Mechanistic understanding of cerium oxide nanoparticle-mediated biofilm formation in Pseudomonas aeruginosa.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-018-3418-8},
pmid = {30324376},
issn = {1614-7499},
support = {No.51722902//National Natural Science Funds for Excellent Young Scholar/ ; No.51421006//the National Science Funds for Creative Research Groups of China/ ; 2018B671X14//the Fundamental Research Funds for the Central Universities/ ; No. 91647206//the Key Program of National Natural Science Foundation of China/ ; BK20160038//the Outstanding Youth Fund of Natural Science Foundation of Jiangsu, China/ ; },
abstract = {In this study, the biofilm formation of Pseudomonas aeruginosa in the presence of cerium oxide nanoparticles (CeO2 NPs) was investigated. With the addition of 0.1 mg/L and 1 mg/L CeO2 NPs, the biofilm development was substantially enhanced. During the attachment process, the enhanced surface hydrophobicity and excess production of mannosan and rhamnolipids in CeO2 NP treatments were detected, which were conductive to the colonization of bacterial cells. During the maturation period, the biofilm biomass was accelerated by the improved aggregation percentage as well as the secretion of extracellular DNA and pyocyanin. The reactive oxygen species (ROS) generated by CeO2 NPs were found to activate the N-butyryl homoserine lactone (C4-HSL) and quinolone signals secreted by Pseudomonas aeruginosa. Moreover, the quorum sensing (QS) systems of rhl and pqs were initiated, reflected by the stimulated expression levels of biofilm formation-related genes rhlI-rhlR, rhlAB, and pqsR-pqsA. The addition of a quorum quencher, furanone C-30, significantly declined the activities of QS-controlled catalase and superoxide dismutase. A dose of antioxidant, ascorbic acid, effectively relieved the accelerating effects of NPs on biofilm formation. These results indicated that CeO2 NPs could accelerate biofilm formation through the interference of QS system by generating ROS, which provides possible targets for controlling biofilm growth in the NP exposure environments.},
}
@article {pmid30322852,
year = {2018},
author = {Palmer, SR and Ren, Z and Hwang, G and Liu, Y and Combs, A and Söderström, B and Vasquez, PL and Khosravi, Y and Brady, LJ and Koo, H and Stoodley, P},
title = {Streptococcus mutans yidC1 and yidC2 impact cell-envelope biogenesis, biofilm matrix and biophysical properties.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00396-18},
pmid = {30322852},
issn = {1098-5530},
abstract = {Proper envelope biogenesis of Streptococcus mutans, a biofilm-forming and dental caries causing oral pathogen, requires two paralogs (yidC1 and yidC2) of the universally conserved YidC/Oxa1/Alb3 family of membrane integral chaperones and insertases. Deletion of either paralog attenuates virulence in vivo but the mechanisms of disruption remain unclear. Here, we determined whether deletion of yidC affects cell surface properties, extracellular glucan production, and/or the structural organization of EPS matrix and biophysical properties of S. mutans biofilm. Compared to wild type, the ΔyidC2 mutant lacked staining with vancomycin at the division septum, while the ΔyidC1 mutant resembled wild-type. Additionally, deletion of either yidC1 or yidC2 resulted in less insoluble glucan synthesis, but produced more soluble glucans, especially at early and mid-exponential growth phases. Alteration of glucan synthesis by both mutants yielded biofilms with less dry-weight and insoluble EPS. In particular, deletion of yidC2 resulted in significant reduction of biofilm biomass and pronounced defects in the spatial organization of the EPS matrix, thus modifying the 3D biofilm architecture. The defective biofilm harbored smaller bacterial clusters with high cell density and less surrounding EPS compared to wild type, which was stiffer in compression yet more susceptible to removal by shear. Together, our results indicate that elimination of either yidC paralog results in changes to the cell envelope and glucan production that ultimately disrupts biofilm development and EPS matrix structure-composition, thereby altering the physical properties of the biofilms and facilitating their removal. YidC proteins, therefore, represent potential therapeutic targets for cariogenic biofilm control.Importance. YidC proteins are membrane localized chaperone insertases that are universally conserved in all bacteria, and are traditionally studied in the context of membrane protein insertion and assembly. Both YidC paralogs of the cariogenic pathogen Streptococcus mutans are required for proper envelope biogenesis and full virulence, indicating these proteins may also contribute to optimal biofilm formation in streptococci. Here we show that deletion of either yidC results in changes to the structure and physical properties of the EPS matrix produced by S. mutans, ultimately impairing optimal biofilm development, diminishing its mechanical stability, and facilitating its removal. Importantly, the universal conservation of bacterial yidC orthologs, combined with our findings, provide a rationale for YidC as a possible drug target for anti-biofilm therapies.},
}
@article {pmid30322270,
year = {2018},
author = {Wijesinghe, MS and Wen, J and Oh, JM and Chow, KF and Sun, Y},
title = {Demonstration of biofilm removal from type 304 stainless steel using pulsed-waveform electropolishing.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-9},
doi = {10.1080/08927014.2018.1492715},
pmid = {30322270},
issn = {1029-2454},
abstract = {This article describes an electrochemical method to remove bacterial biofilm from a stainless steel (SS) surface using a potential pulse/reverse pulse technique. This technique employs a periodic waveform that consists of anodic and cathodic pulses. The pulses can effectively strip a thin layer of metal off the SS surface, along with the adherent biofilm, in a saline solution. Not only can the pulses effectively remove biofilm from the SS surface, but they also regenerate the original mirror-like shiny surface. The importance of this electrochemical biofilm removal method is its wide applicability for any types of biofilms. That is, instead of directly removing the biofilm, it removes a very thin layer of the metal under the biofilm. Thus, the removal process is independent to the nature of the biofilms. Furthermore, this electrochemical biofilm removal method is rapid (less than 30 s of potential pulse time) and does not require hazardous chemicals.},
}
@article {pmid30320445,
year = {2018},
author = {Zhang, Y and Li, C and Wu, Y and Zhang, Y and Zhou, Z and Cao, B},
title = {A Microfluidic Gradient Mixer-Flow Chamber as a New Tool to Study Biofilm Development under Defined Solute Gradients.},
journal = {Biotechnology and bioengineering},
volume = {},
number = {},
pages = {},
doi = {10.1002/bit.26852},
pmid = {30320445},
issn = {1097-0290},
abstract = {Understanding the dynamics of biofilm development in response to chemical cues and signals is required toward the development of controllable biofilm-mediated bioprocesses. In this study, we report a new biofilm growth system that integrates a microfluidic gradient mixer with a biofilm growth chamber. The biofilm growth system allows biofilms grow under defined solute gradients and enables non-destructively monitor the biofilm development dynamics in response to the defined gradients. The solute gradients generated in the system were simulated and then validated experimentally. We then demonstrated the applicability of the biofilm growth system in studying biofilm development under defined solute gradients. Specifically, we examined biofilm development of Shewanella oneidensis and Comamonas testosteroni under a defined calcium and nitrate gradient, respectively. Using two C. testosteroni strains (WDL7 and I2), we further demonstrated the applicability of our biofilm growth system to study the development of co-culture biofilms under a defined solute gradient. Our results showed that the biofilm growth system we developed here can be a promising tool to reveal the dynamics of biofilm development in response to chemical cues and signals as well as the inter-organism interactions in co-culture biofilms. This article is protected by copyright. All rights reserved.},
}
@article {pmid30320255,
year = {2018},
author = {Bagchi, D and Rathnam, VSS and Lemmens, P and Banerjee, I and Pal, SK},
title = {NIR-Light-Active ZnO-Based Nanohybrids for Bacterial Biofilm Treatment.},
journal = {ACS omega},
volume = {3},
number = {9},
pages = {10877-10885},
doi = {10.1021/acsomega.8b00716},
pmid = {30320255},
issn = {2470-1343},
abstract = {Nanomaterials with antimicrobial properties triggered by external stimuli appear to be a promising and innovative substitute for the destruction of antibiotic-resistant superbugs as they can induce multiple disruptions in the cellular mechanism. This study demonstrates the use of squaraine (SQ) dye as the photosensitive material, activated in the near-infrared tissue-transparent therapeutic window. The dye has been covalently attached to the ZnO nanoparticle surface, forming ZnO-SQ nanohybrids. The formation of the nanohybrids is confirmed using Fourier transform infrared and other optical spectroscopic methods. The photoinduced interfacial electron transfer process (as confirmed using the time-resolved fluorescence technique) from the excited state of SQ to the conduction band of ZnO is responsible for the greater reactive oxygen species (ROS) generation ability of the nanohybrid. The production of photoactivated ROS (especially singlet oxygen species) by ZnO-SQ provides remarkable antimicrobial action against clinically significant Staphylococcus aureus. Detailed investigations suggest synergistic involvement of cell membrane disruption and nanoparticle internalization followed by photoinduced intracellular ROS generation, which result in an unprecedented 95% bacterial killing activity by the nanohybrid. Moreover, the efficacy of the nanohybrid for disruption of bacterial biofilms has been examined. The electron microscopic images suggest significant bacterial cell death following structural alteration and reduced adherence property of the biofilms. Nanodimension-driven greater internalization of ZnO-SQ followed by an improved dissolution of ZnO in an acidic environment of the biofilm as well as red-light-driven interfacial charge separation and ROS generation improves the efficacy of the material for biofilm destruction. An artificial medical implant mimicking titanium sheets coated with ZnO-SQ depicts light-triggered disruption in the adherence property of matured biofilms. The cytotoxicity and hemolysis assays show inherent biocompatibility of the photoactive nanohybrid. This study is notably promising for the treatment of life-threatening drug-resistant infections and eradication of biofilms formed within artificial implants.},
}
@article {pmid30317126,
year = {2018},
author = {Harper, RA and Carpenter, GH and Proctor, GB and Harvey, RD and Gambogi, RJ and Geonnotti, AR and Hider, R and Jones, SA},
title = {Diminishing biofilm resistance to antimicrobial nanomaterials through electrolyte screening of electrostatic interactions.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {173},
number = {},
pages = {392-399},
doi = {10.1016/j.colsurfb.2018.09.018},
pmid = {30317126},
issn = {1873-4367},
abstract = {The extracellular polymer substances (EPS) generated by biofilms confers resistance to antimicrobial agents through electrostatic and steric interactions that hinder molecular diffusion. This resistance mechanism is particularly evident for antibacterial nanomaterials, which inherently diffuse more slowly compared to small organic antibacterial agents. The aim of this study was to determine if a biofilm's resistance to antibacterial nanomaterial diffusion could be diminished using electrolytes to screen the EPS's electrostatic interactions. Anionic (+) alpha-tocopherol phosphate (α-TP) liposomes were used as the antimicrobial nanomaterials in the study. They self-assembled into 700 nm sized structures with a zeta potential of -20 mV that were capable of killing oral bacteria (S. oralis growth inhibition time of 3.34 ± 0.52 h). In a phosphate (-ve) buffer the -ve α-TP liposomes did not penetrate multispecies oral biofilms, but in a Tris (hydroxymethyl)aminomethane (+ve) buffer they did (depth - 12.4 ± 3.6 μm). The Tris did not modify the surface charge of the α-TP nanomaterials, rather it facilitated the α-TP-biofilm interactions through electrolyte screening (Langmuir modelled surface pressure increase of 2.7 ± 1.8 mN/ m). This data indicated that EPS resistance was mediated through charge repulsion and that this effect could be diminished through the co-administration of cationic electrolytes.},
}
@article {pmid30317111,
year = {2018},
author = {Corzo-Ariyama, HA and García-Heredia, A and Heredia, N and García, S and León, J and Jaykus, L and Solís-Soto, L},
title = {Phylogroups, pathotypes, biofilm formation and antimicrobial resistance of Escherichia coli isolates in farms and packing facilities of tomato, jalapeño pepper and cantaloupe from Northern Mexico.},
journal = {International journal of food microbiology},
volume = {290},
number = {},
pages = {96-104},
doi = {10.1016/j.ijfoodmicro.2018.10.006},
pmid = {30317111},
issn = {1879-3460},
abstract = {The most commonly used indicator of fecal contamination in fresh produce production and packing is Escherichia coli. In depth analysis of the prevalence and characteristics of naturally occurring E. coli strains in these environments is important because it can (1) serve as an indicator of sources of fecal contamination; and (2) provide information on strain pathogenicity, persistence, and other defining characteristics such as multidrug resistance. In this study, we analyzed 341 E. coli strains isolated from the jalapeño pepper, tomato and cantaloupe farm environments, in Northeast Mexico. Strains were isolated from produce, farmworkers' hands, soil and water. Pathotypes, genotypes, biofilm formation and antibiotic resistance were characterized. Phylogenetic subgroups and identification of diarrheagenic E. coli were determined by PCR; biofilm formation was quantified using a plate-based colorimetric method. Antibiotic resistance was analyzed by the Kirby Bauer diffusion disc method. Most isolates (N = 293, 86%) belonged to phylogenetic group A. Only four isolates (1.2%) were diarrheagenic: EPEC (N = 3) and ETEC (N = 1). Antibiotic resistance to tetracycline (23.2%) and ampicillin (19.9%) was high, and only 3.5% of the strains presented resistance to >5 antibiotics. Biofilms were produced by most strains (76%), among which 34.4% were categorized as high producers. The presence of antibiotic resistant E. coli strains that may contain gene markers for pathogenicity and which can form biofilms suggests potential health risks for consumers.},
}
@article {pmid30316009,
year = {2018},
author = {Mahdhi, A and Leban, N and Chakroun, I and Bayar, S and Mahdouani, K and Majdoub, H and Kouidhi, B},
title = {Use of extracellular polysaccharides, secreted by Lactobacillus plantarum and Bacillus spp., as reducing indole production agents to control biofilm formation and efflux pumps inhibitor in Escherichia coli.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2018.10.010},
pmid = {30316009},
issn = {1096-1208},
abstract = {The overuse of antibiotics and biofilm formation ability has led to the emergence of resistant bacterial strains. The combined use of several antibiotics has been an efficient strategy to overcome this resistance. In this study, two exopolysaccharides (EPS) obtained from Lactobacillus plantarum (EPS-Lp) and Bacillus spp. (EPS-B), isolated from a traditional Tunisian food &quot;ricotta cheese&quot; and hypersaline environment respectively, were used to counteract the biofilm formation and efflux pumps activities in Escherichia coli ATCC35218. The obtained results revealed that the tested EPSs can be effective against E. coli at a concentration > 1 mg/ml and were able to modulate biofilm formation by 50%. Moreover, at a concentration of 512 μg/ml, the tested EPSs inhibit the EtBr efflux in the tested bacteria and no significant difference was shown compared to cells treated with reserpine (P > 0.05). The positive effect of the tested EPSs may be due to the decrease of Indole production level proposed as a signal involved in quorum sensing and through the significant reduction of the hydrophobicity percentage between the treated and untreated cells. Overall, EPS-Lp and EPS-B, when using at appropriate concentration, may inhibit biofilm formation and reduce efflux pumps implicated in bacterial adhesion and antimicrobial resistance. These results make them an interesting candidate in the design of a new strategies to control bacterial biofilm-associated infections.},
}
@article {pmid30315918,
year = {2018},
author = {Koppen, BC and Mulder, PPG and de Boer, L and Riool, M and Drijfhout, JW and Zaat, SAJ},
title = {Synergistic Microbicidal Effect of Cationic Antimicrobial Peptides and Teicoplanin against Planktonic and Biofilm-Encased Staphylococcus aureus.},
journal = {International journal of antimicrobial agents},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijantimicag.2018.10.002},
pmid = {30315918},
issn = {1872-7913},
abstract = {Antibiotic resistance and biofilm formation are the major reasons for failure in treatment of bacterial infections. We therefore aimed to identify synergistic combinations of conventional antibiotics and novel Synthetic Antimicrobial and Antibiofilm Peptides (SAAPs) inspired by the structures of the natural human cationic peptides LL-37 and thrombocidin-1 (TC-1). The LL-37-inspired lead peptide SAAP-148 was combined with antibiotics of different classes against Staphylococcus aureus and showed synergy with teicoplanin. Synergy with teicoplanin was also observed with LL-37, the LL-37-inspired SAAP-276 and the TC-1-inspired TC84. Interestingly, no synergy was observed against Staphylococcus epidermidis. Furthermore, teicoplanin combined with SAAP-148 or SAAP-276 showed strong interaction against S. aureus biofilms. The dltABCD operon and the mprF gene in S. aureus conferred resistance to LL-37, but SAAP-148 proved to be indifferently potent against wild-type-, ΔdltA- and ΔmprF S. aureus strains. When used singly, relatively high concentrations of both LL-37 and teicoplanin (30-120 µM and 4-32 mg/L, respectively) were required to kill S. aureus. Resistance to LL-37 in S. aureus, was overcome by combined use of teicoplanin and LL-37. Thus, teicoplanin potentiates peptide LL-37, enhancing the effectivity of the innate defense, and combining of our novel peptides with teicoplanin offers prospect for enhanced effectivity of treatment of S. aureus infections, including biofilms.},
}
@article {pmid30312918,
year = {2018},
author = {Zhang, H and Tian, Y and Kang, M and Chen, C and Song, Y and Li, H},
title = {Effects of chlorination/chlorine dioxide disinfection on biofilm bacterial community and corrosion process in a reclaimed water distribution system.},
journal = {Chemosphere},
volume = {215},
number = {},
pages = {62-73},
doi = {10.1016/j.chemosphere.2018.09.181},
pmid = {30312918},
issn = {1879-1298},
abstract = {In this work, reclaimed water treated with sodium hypochlorite (NaClO) or chlorine dioxide (ClO2) at 1, 2, and 4 mg/L was operated successively for 30 days respectively, in annular reactors with new cast iron coupons, corresponding to stages I (days 0-30), II (days 31-60), and III (days 61-90). The Illumina HiSeq 2500 sequencing platform was used to analyze the bacterial community composition, scanning electron microscopy and X-ray diffraction analyses were conducted to characterize corrosion scales, and the weight loss method was served to determine the general corrosion rate. Results reveal the precise disinfection effect on biofilm bacteria to be dose dependent and species specific. In stage I, disinfection caused a reduction in the number of operational taxonomic units, but, had little effect on biofilm composition. In stage II, NaClO and ClO2 induced a reduction of Proteobacteria proportion, but increased the dominance of Firmicutes; the diminished Proteobacteria in NaClO test mainly included Gammaproteobacteria, while, that in ClO2 test mainly included the Gammaproteobacteria and Betaproteobacteria. In stage III, Firmicutes presented a certain resistance to NaClO and ClO2 as the accumulation of corrosion scales. Results also indicated that disinfection enhanced the corrosion process, and the promoting effect of ClO2 was more pronounced than that of NaClO. Moreover, this promoting effect was more obvious in stage I than that in the latter two stages. The strong oxidization effect associated with disinfection in stage I was the dominant factor promoting corrosion, whereas, the bacterial community also played a crucial role in stages II and III.},
}
@article {pmid30310963,
year = {2018},
author = {Sakr, MM and Aboshanab, KM and Elkhatib, WF and Yassien, MA and Hassouna, NA},
title = {Overexpressed recombinant quorum quenching lactonase reduces the virulence, motility and biofilm formation of multidrug-resistant Pseudomonas aeruginosa clinical isolates.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-018-9418-2},
pmid = {30310963},
issn = {1432-0614},
abstract = {The increasing occurrence of resistance among Pseudomonas aeruginosa clinical isolates necessitates finding alternatives to antibiotics for controlling the infection of such pathogenic bacteria. In this study, lactonase gene ahl-1 from Bacillus weihenstephanensis isolate-P65 was successfully cloned and expressed in Escherichia coli BL21 (DE3) under the control of T7 promoter for utilizing its quorum quenching activity against three multidrug-resistant (MDR) P. aeruginosa clinical isolates. The biological activity of the overexpressed lactonase enzyme (Ahl-1), tested using a synthetic signal and Chromobacterium violaceum CV026 as a biosensor, displayed good catalytic activity using hexanoyl homoserine lactone (HHL) as a substrate and Chromobacterium violaceum (CV026) as a biosensor (77.2 and 133 nm min-1 for the crude and the purified Ahl-lactonase enzymes, respectively). Upon challenging its ability to inhibit the virulence of three MDR P. aeruginosa clinical isolates, recombinant Ahl-1 successfully prevented the accumulation of acylhomoserine lactone signals resulting in a significant reduction in the investigated virulence determinants; protease (from 40 up to 75.5%), pyocyanin (48-75.9%), and rhamnolipids (52.7-63.4%) (P value < 0.05). Ahl-1 also displayed significant inhibitory activities on the swarming motility and biofilm formation of the three tested MDR P. aeruginosa clinical isolates (P value < 0.05). Consequently, Ahl-1 lactonase enzyme in this study is considered a promising therapeutic agent to inhibit P. aeruginosa pathogenicity with no fear of emergence of resistance.},
}
@article {pmid30308791,
year = {2019},
author = {Jacotot, A and Marchand, C and Allenbach, M},
title = {Biofilm and temperature controls on greenhouse gas (CO2 and CH4) emissions from a Rhizophora mangrove soil (New Caledonia).},
journal = {The Science of the total environment},
volume = {650},
number = {Pt 1},
pages = {1019-1028},
doi = {10.1016/j.scitotenv.2018.09.093},
pmid = {30308791},
issn = {1879-1026},
abstract = {Seasonal variations of CO2 and CH4 fluxes were investigated in a Rhizophora mangrove forest that develops under a semi-arid climate, in New Caledonia. Fluxes were measured using closed incubation chambers connected to a CRDS analyzer. They were performed during low tide at light, in the dark, and in the dark after having removed the top 1-2 mm of soil, which may contain biofilm. CO2 and CH4 fluxes ranged from 31.34 to 187.48 mmol m-2 day-1 and from 39.36 to 428.09 μmol m-2 day-1, respectively. Both CO2 and CH4 emissions showed a strong seasonal variability with higher fluxes measured during the warm season, due to an enhanced production of these two gases within the soil. Furthermore, CO2 fluxes were higher in the dark than at light, evidencing photosynthetic processes at the soil surface and thus the role of biofilm in the regulation of greenhouse gas emissions from mangrove soils. The mean δ13C-CO2 value of the CO2 fluxes measured was -19.76 ± 1.19‰, which was depleted compared to the one emitted by root respiration (-22.32 ± 1.06‰), leaf litter decomposition (-21.43 ± 1.89‰) and organic matter degradation (-22.33 ± 1.82‰). This result confirmed the use of the CO2 produced within the soil by the biofilm developing at its surface. After removing the top 1-2 mm of soil, both CO2 and CH4 fluxes increased. Enhancement of CH4 fluxes suggests that biofilm may act as a physical barrier to the transfer of GHG from the soil to the atmosphere. However, the δ13C-CO2 became more enriched, evidencing that the biofilm was not integrally removed, and that its partial removal resulted in physical disturbance that stimulated CO2 production. Therefore, this study provides useful information to understand the global implication of mangroves in climate change mitigation.},
}
@article {pmid30308310,
year = {2018},
author = {Trigo Gutierrez, JK and Volpato Sanitá, P and Tedesco, AC and Pavarina, AC and de Oliveira Mima, EG},
title = {Effect of Chloroaluminium phthalocyanine in cationic nanoemulsion on photoinactivation of multispecies biofilm.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2018.10.005},
pmid = {30308310},
issn = {1873-1597},
abstract = {BACKGROUND: Photosensitizers in nanocarriers have been investigated for antimicrobial Photodynamic Therapy (aPDT). However, most studies are focused against microorganisms in planktonic or monospecies biofilm. Thus, this in vitro study evaluated the effect of aPDT using Chloroaluminium phthalocyanine (ClAlPc) in cationic nanoemulsion (NE) against Candida albicans, Candida glabrata and Streptococcus mutans grown as multispecies biofilm.<br><br>METHODS: Standard suspensions of each microorganism were added into wells of a microtiter plate for biofilm growth for 48 hours in a candle jar. The biofilms were incubated with ClAlPc in cationic NE at 31.8 μM for 30 minutes and illuminated with red light fluence of 39.3 J/cm2 (P + L + group). Additional samples were treated only with photosensitizer (P + L-) or red light (P-L+) or neither (P-L-, control group). aPDT efficacy was assessed by colony quantification, biofilm's metabolic activity, total biomass, and confocal microscopy. Data were analyzed by ANOVA/Welch and post-hoc Tukey/Games-Howell tests (α = 0.05).<br><br>RESULTS: aPDT reduced the colony count in 1.30 to 2.24 lg10 and the metabolic activity in 53.7% compared with the control group (P-L-). The total biomass showed no statistical difference among the groups. The confocal microscopy analyzes showed uptake of the PS in the biofilm, and dead cells was observed in the biofilm treated with aPDT.<br><br>CONCLUSION: aPDT mediated by ClAlPc in cationic NE promoted photoinactivation of the multispecies biofilm, which was confirmed by colony quantification, metabolic activity, and confocal microscopy. However, the total biomass of the biofilm was not affected by the treatment.},
}
@article {pmid30308309,
year = {2018},
author = {Batinić, M and Ročana, M and Budimir, A and Anić, I and Bago, I},
title = {Comparison of final disinfection protocols using antimicrobial photodynamic therapy and different irrigants after single-file reciprocating instrumentation against intracanal bacterial biofilm - an in vitro study.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2018.10.006},
pmid = {30308309},
issn = {1873-1597},
abstract = {BACKGROUND: The aim of the study was to compare the efficacy of antimicrobial photodynamic therapy (aPDT) with irrigation protocols that include sodium hypochlorite (NaOCl), ethylenediaminotetraacetic acid (EDTA) or QMiX (combined irrigant: EDTA, chlorhexidine, detergent) solution after single-file reciprocating root canal instrumentation.<br><br>METHODS: The study sample included 68 extracted mandibular human single canal teeth. The canals were inoculated with bacterial suspension made of wild strain of Enterococcus faecalis. After 17 days of incubation, the samples were assigned to experimental groups according to the final disinfection protocol and a control group. The root canals in all groups were, firstly, instrumented with Wave One Gold reciprocating system. Then the canals were disinfected as follows: Group 1. 2.5% NaOCl and EDTA followed by the application of the aPDT; Group 2. 2.5% NaOCl, EDTA and 2.5% NaOCl; Group 3. 2.5% NaOCl and QMIX solution; Group 4. 2.5% NaOCl and EDTA. In the control group, the canals were irrigated with saline solution. Microbiological samples were collected at baseline, after single-file instrumentation and after the final disinfection protocols. The samples were plated onto Mitis Salivarius agar plates for incubation. The colony forming units (CFUs) were counted, and the final number was determined based on the dilution factor.<br><br>RESULTS: Reciprocating single-file instrumentation reduced CFUs significantly in all groups (p<0.05). No significant difference between Group 1 and Group 2 was observed (p=0.178). Irrigation with the QMiX was more efficient than the aPDT (p=0.02).<br><br>CONCLUSIONS: The aPDT used after irrigation with NaOCl and EDTA demonstrated similar antimicrobial efficacy as conventional irrigation with NaOCl.},
}
@article {pmid30308132,
year = {2018},
author = {Ong, KS and Mawang, CI and Daniel-Jambun, D and Lim, YY and Lee, SM},
title = {Current anti-biofilm strategies and potential of antioxidants in biofilm control.},
journal = {Expert review of anti-infective therapy},
volume = {},
number = {},
pages = {},
doi = {10.1080/14787210.2018.1535898},
pmid = {30308132},
issn = {1744-8336},
abstract = {INTRODUCTION: Biofilm formation is a strategy for microorganisms to adapt and survive in hostile environments. Microorganisms that are able to produce biofilms are currently recognized as a threat to human health. Areas covered: Many strategies have been employed to eradicate biofilms, but several drawbacks from these methods had subsequently raised concerns on the need for alternative approaches to effectively prevent biofilm formation. One of the main mechanisms that drives a microorganism to transit from a planktonic to a biofilm-sessile state, is oxidative stress. Chemical agents that could target oxidative stress regulators, for instance antioxidants, could therefore be used to treat biofilm-associated infections. Expert commentary: The focus of this review is to summarize the function and limitation of the current anti-biofilm strategies and will propose the use of antioxidants as an alternative method to treat, prevent and eradicate biofilms. Studies have shown that water-soluble and lipid-soluble antioxidants can reduce and prevent biofilm formation, by influencing the expression of genes associated with oxidative stress. Further in-vivo work should be conducted to ensure the efficacy of these antioxidants in a biological environment. Nevertheless, antioxidants are promising anti-biofilm agents, and thus is a potential solution for biofilm associated infections in the future.},
}
@article {pmid30306008,
year = {2018},
author = {Kim, G and Dasagrandhi, C and Kang, EH and Eom, SH and Kim, YM},
title = {In vitro antibacterial and early stage biofilm inhibitory potential of an edible chitosan and its phenolic conjugates against Pseudomonas aeruginosa and Listeria monocytogenes.},
journal = {3 Biotech},
volume = {8},
number = {10},
pages = {439},
doi = {10.1007/s13205-018-1451-4},
pmid = {30306008},
issn = {2190-572X},
abstract = {In the present study, the antibacterial potential of chitosan grafted with phenolics (CPCs) such as caffeic acid (CCA), ferulic (CFA), and sinapic acid (CSA) were evaluated against foodborne pathogens like Pseudomonas aeruginosa (PA) and Listeria monocytogenes (LM). The geometric means of minimum inhibitory concentration (MIC range 0.05-0.33 mg/ml), bactericidal concentration (MBC range 0.30-0.45 mg/ml), biofilm inhibitory concentration (BIC range 0.42-0.83 mg/ml), and biofilm eradication concentration (BEC range 1.71-3.70 mg/ml) of CPCs were found to be lower than the MIC (0.12-1.08 mg/ml), MBC (0.17-1.84 mg/ml), BIC (4.0-4.50 mg/ml), and BEC (17.4-23.0 mg/ml) of unmodified chitosan against PA and LM. CPCs attenuated the biofilms of PA and LM by increasing the membrane permeability of bacteria embedded within the biofilms. Further, sub MIC of CPCs (0.5 × MIC) significantly reduced the biofilm adhesion (p < 0.001) by representative strains of LM (CCA: 72.2 ± 3.5, CFA: 79.3 ± 0.9, and CSA: 74.9 ± 1.5%) and PA (CCA: 64 ± 1.1, CFA: 67.8 ± 0.8, and CSA: 65.7 ± 4.9%). These results suggested the antibacterial and anti-biofilm potential of CPCs that can be exploited to control foodborne pathogenic infections.},
}
@article {pmid30305150,
year = {2018},
author = {Manandhar, S and Singh, A and Varma, A and Pandey, S and Shrivastava, N},
title = {Evaluation of methods to detect in vitro biofilm formation by staphylococcal clinical isolates.},
journal = {BMC research notes},
volume = {11},
number = {1},
pages = {714},
doi = {10.1186/s13104-018-3820-9},
pmid = {30305150},
issn = {1756-0500},
abstract = {OBJECTIVE: Staphylococcus genus comprising both Staphylococcus aureus and coagulase negative staphylococci (CoNS) are widely distributed in nature and can infect diversity of hosts. Indeed, staphylococci are the major pathogens causing biofilm associated infections caused by contaminated hospital indwelling devices. These infections are persistent in nature being highly refractory to various stresses including antibiotics. Implementation of efficient diagnostic techniques for the biofilm production would help minimize the disease burden. Thus, early detection of pathogenic strains producing biofilms warrant the utmost importance in diagnostic laboratories especially in resource limited settings.<br><br>RESULT: Among 375 isolates collected from different clinical specimens, 214 (57%) were identified as coagulase negative staphylococci and 161 (43%) S. aureus. Detection of In-vitro biofilm formation in these isolates were carried out by three commonly used phenotypic assays and a genotypic assay. While evaluating the results, tissue-culture method with supplemented glucose and sucrose showed the best correlation with the results of genotypic assay.},
}
@article {pmid30304991,
year = {2018},
author = {Li, H and Qin, Y and Mao, X and Zheng, W and Luo, G and Xu, X and Zheng, J},
title = {Silencing of cyt-c4 led to decrease of biofilm formation in Aeromonas hydrophila.},
journal = {Bioscience, biotechnology, and biochemistry},
volume = {},
number = {},
pages = {1-12},
doi = {10.1080/09168451.2018.1528543},
pmid = {30304991},
issn = {1347-6947},
abstract = {Aquaculture suffers from a number of diseases caused by Aeromonas hydrophila. Biofilm can protect bacteria from antibiotic therapy. To identify the genes those play crucial roles in A. hydrophila biofilm formation, a library of mini-Tn10 transposon insertion mutants of A. hydrophila B11 has been constructed, and 10 mutants were subjected to biofilm formation assay. The biofilm formation ability of mutant (B188) was significantly decreased compared with B11. The DNA sequence flanking the mini-Tn10 transposon inserted showed that an ORF of approximately 576 bp of the mutant strain B188 was inserted. This ORF putatively displays the highest identity (92%) with the cytochrome c4 gene (cyt-c4) of A. hydrophila subsp. hydrophila ATCC 7966. Silencing cyt-c4 led to deficiencies in biofilm formation, adhesion, drug resistance and pathogenicity of A. hydrophila, which suggests that cyt-c4 plays crucial role in the biofilm formation and virulence mechanisms of A. hydrophila.<br><br>ABBREVIATIONS: GEN: gentamycin; SDZ: sulfadiazine; AK: amikacin; P: penicillin; CFP: cefoperazone; LEV: levofloxacin; MH: minocycline; FFC: florfenicol; TE: tetracycline; AMP: ampicillin; KAN: kanamycin; STR: streptomycin; SXT: sulfamethoxazole/trimethoprim; DO: doxycycline; OT: Oxytetracycline.},
}
@article {pmid30304914,
year = {2018},
author = {Ham, Y and Kim, TJ},
title = {Nitrogen Sources Inhibit Biofilm Formation of Xanthomonas oryzae pv. oryzae.},
journal = {Journal of microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.4014/jmb.1808.08025},
pmid = {30304914},
issn = {1738-8872},
abstract = {Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight, which results in a severe economic damage to rice farms. Xoo produces biofilms for pathogenesis and survival both inside and outside the host. Biofilms, which are important virulence factors, play a key role in causing the symptoms of Xoo infection. In the present study, we investigated nutritional conditions for the biofilm formation of Xoo. Although the biofilm formation of Xoo may be initiated by their interactions with the host, there is no mature biofilm formation without the support of favorable nutritional conditions. Nitrogen sources inhibited biofilm formation by overwhelming the positive effect of cell growth on biofilm formation. Limited nutrients with low amino acid concentration supported the biofilm formation of Xoo in the xylem sap rather than in the phloem sap of rice.},
}
@article {pmid30304890,
year = {2018},
author = {Shi, C and Li, M and Muhammad, I and Ma, X and Chang, Y and Li, R and Li, C and He, J and Liu, F},
title = {Combination of berberine with ciprofloxacin reduce a multi-resistant Salmonella strain biofilm formation by depressing mRNA expressions of luxS, rpoE and ompR.},
journal = {Journal of veterinary science},
volume = {},
number = {},
pages = {},
pmid = {30304890},
issn = {1976-555X},
abstract = {Bacterial biofilms have been demonstrated to be closely related to clinical infections and mainly contribute to drug resistance. Berberine, which is the main component of Coptis chinensis, has been reported to have efficient antibacterial activity. This study aimed to investigate the potential effect of combination of berberine with ciprofloxacin (CIP) to inhibit Salmonella biofilm formation and the effect on the related genes (rpoE, luxS, ompR) expressions. The fractional inhibitory concentration index of the combination of berberine with CIP is 0.75 showing a synergistic antibacterial effect. The biofilm adhesion rate and growth curve showed that the multi-resistant Salmonella strain had potential ability to form biofilm relative to CVCC528, and the antibiofilm effects were in a dose-dependent manner. Biofilm microstructures were rarely observed at 1/2×MIC/FIC concentrations, and the combination showed stronger antibiofilm effect than each of the antimicrobial agent used alone at 1/4×FIC concentration. LuxS, rpoE and ompR mRNA expressions were significantly repressed (p ＜ 0.01) at 1/2×MIC/FIC concentrations, and the combination repressed mRNA expressions more strongly at 1/4×FIC concentration. The results indicated that the combination of berberine and CIP showed synergistic effect and more effective to inhibit Salmonella biofilm formation via repression of luxS, rpoE and ompR mRNA expressions.},
}
@article {pmid30304271,
year = {2018},
author = {Sahal, G and Bilkay, IS},
title = {Distribution of clinical isolates of Candida spp. and antifungal susceptibility of high biofilm-forming Candida isolates.},
journal = {Revista da Sociedade Brasileira de Medicina Tropical},
volume = {51},
number = {5},
pages = {644-650},
doi = {10.1590/0037-8682-0136-2018},
pmid = {30304271},
issn = {1678-9849},
abstract = {INTRODUCTION: The increase in the incidence of fungal infections, especially those caused by Candida albicans and other Candida species, necessitates the understanding and treatment of Candida-associated infections. In this study, we aimed to investigate the identification, distribution, and biofilm formation ability of different clinical Candida isolates and evaluate the distribution and antifungal susceptibilities of high biofilm-forming (HBF) Candida isolates.<br><br>METHODS: For identification, carbohydrate fermentation, carbohydrate assimilation, and ChromAgar tests were used. Biofilm formation was assessed using crystal violet binding assay, while the susceptibility to antifungal agents was determined using ATBTM Fungus 3 test kits.<br><br>RESULTS: The majority of Candida species were C. parapsilosis (31.3%; 31/99) and C. tropicalis (30.3%; 30/99). C. tropicalis was found to be the most frequently isolated species among all HBF Candida species. HBF Candida isolates were more frequently isolated from vaginal swab (35.7%; 10/28), tracheal aspirate (17.9%; 5/28), and urine (17.9%; 5/28). The majority of tested isolates were resistant to itraconazole and voriconazole, whereas no isolate was deemed resistant to 5-flucytosine.<br><br>CONCLUSIONS: C. tropicalis displays the highest biofilm formation ability among all the Candida species evaluated, and HBF Candida isolates were more frequently seen in vaginal swab, tracheal aspirate, and urine samples. Our findings revealed that 5-flucytosine is the most efficient antifungal agent against HBF Candida isolates.},
}
@article {pmid30304265,
year = {2018},
author = {Sohail, M and Latif, Z},
title = {Molecular analysis, biofilm formation, and susceptibility of methicillin-resistant Staphylococcus aureus strains causing community- and health care-associated infections in central venous catheters.},
journal = {Revista da Sociedade Brasileira de Medicina Tropical},
volume = {51},
number = {5},
pages = {603-609},
doi = {10.1590/0037-8682-0373-2017},
pmid = {30304265},
issn = {1678-9849},
abstract = {INTRODUCTION: The behavior of methicillin-resistant Staphylococcus aureus (MRSA) isolated from central venous catheter-related infection was evaluated to determine its biofilm potential, antimicrobial resistance, and adhesion genes.<br><br>METHODS: A total of 1,156 central venous catheters (CVC) were evaluated to screen for pathogens. Antimicrobial sensitivity, biofilm formation potential, and molecular analysis of MRSA were examined following standard guidelines.<br><br>RESULTS: Of the 1,156 samples, 882 (76%) were colonized by bacteria or candida. Among the infected patients, 69% were male and 36% were female with median age of 32 years. Staphylococcus aureus infected 39% (344/882) of CVCs in patients. Of the 59% (208/344) of patients with MRSA, 57% had community acquired MRSA and 43% had hospital acquired MRSA. Linezolid and vancomycin killed 100% of MRSA; resistance levels to fusidic acid, doxycycline, clindamycin, azithromycin, amikacin, trimethoprim-sulfamethoxazole, gentamycin, tobramycin, and ofloxacin were 21%, 42%, 66%, 68%, 72%, 85%, 95%, 97%, and 98% respectively. Strong biofilm was produced by 23% of samples, moderate by 27%, and weak by 50% of MRSA. The presence of adhesion genes, sdrC and sdrD (90%), eno (87%), fnbA (80%), clfA and sdrE (67%), fnbB, sdrD (61%), and cna (51%), in most MRSA samples suggested that the adhesion genes are associated with biofilm synthesis.<br><br>CONCLUSIONS: The superbug MRSA is a major cause of CVC-related infection. Antibiotic resistance to major classes of antibiotics and biofilm formation potential enhanced superbug MRSA virulence, leading to complicated infection. MRSA causes infection in hospitals, communities, and livestock.},
}
@article {pmid30304123,
year = {2018},
author = {Yang, Y and Li, W and Hou, B and Zhang, C},
title = {Quorum sensing LuxS/autoinducer-2 inhibits Enterococcus faecalis biofilm formation ability.},
journal = {Journal of applied oral science : revista FOB},
volume = {26},
number = {},
pages = {e20170566},
doi = {10.1590/1678-7757-2017-0566},
pmid = {30304123},
issn = {1678-7765},
abstract = {OBJECTIVE: To investigate the relation between biofilm formation ability and quorum sensing gene LuxS/AI-2.<br><br>MATERIALS AND METHODS: Enterococcus faecalis (E. faecalis) standard strain ATCC 29212 was used in the study. Long flanking homology polymerase chain reaction method was used to build the LuxS gene knockout strain. Sequential culture turbidity measurement and CFU counting were used to assess the proliferation ability of E. faecalis after the depletion of LuxS. 96-well plate assay was used to quantify the biofilm formation ability; CLSM was used to observe the attached bacteria areas, while scanning electron microscopy (SEM) was performed to observe biofilm microstructure conditions.<br><br>RESULTS: LuxS gene knockout strains were successfully constructed and identified. The results showed that proliferation ability of E. faecalis was not affected by the depletion of the luxS gene, and the biofilm formation ability of ΔLuxS 29212 significantly decreased (P<0.05).<br><br>CONCLUSIONS: Collectively, our studies provide the LuxS gene's key role in controlling biofilm formation of E. faecalis, which presented a negative regulation, and furthermore, providing us a possible way to conquer the persistent apical periodontitis.},
}
@article {pmid30304005,
year = {2018},
author = {Oliveira Junior, NM and Mendoza Marin, DO and Leite, ARP and Pero, AC and Klein, MI and Compagnoni, MA},
title = {Influence of the use of complete denture adhesives on microbial adhesion and biofilm formation by single- and mixed-species.},
journal = {PloS one},
volume = {13},
number = {10},
pages = {e0203951},
doi = {10.1371/journal.pone.0203951},
pmid = {30304005},
issn = {1932-6203},
abstract = {OBJECTIVES: To verify whether the Ultra Corega Cream and Corega Strip Denture Adhesive adhesives interfere in the microbial adhesion and biofilm formation by Candida albicans and Lactobacillus casei in single- and mixed-species settings, and observe whether synergistic or antagonistic relationships between these species occur.<br><br>METHODS: Specimens made from heat-polymerized acrylic resin (Lucitone 550) were fabricated (n = 144) with a circular shape and standardized roughness (3.0 μm ±0.3 Ra) and were divided into three groups: Without Adhesive (WA), with Ultra Corega Cream adhesive (CA) and Corega Strips adhesive (SA). These groups were divided into three subgroups each: C. albicans single-species, L. casei single-species and C. albicans with L. casei (mixed-species). Microbial adhesion and biofilm formation assays were performed in duplicate at four distinct experimental times (n = 8 per experimental condition). The amount of each microorganism on the surfaces of the specimens was observed by counting of the Colony Forming Units (CFU) per substrate. Additional specimens were characterized by Scanning Electron Microscopy (SEM), with 18 specimens being used in this analysis (n = 18), 2 per experimental condition (n = 2). Two-way ANOVA and Tukey's test for multiple comparisons were employed, using α≤0.05.<br><br>RESULTS: L. casei (mixed-species) adhered more on the WA substrate than the CA, while C. albicans (single- and mixed-species) adhered more on the SA. C. albicans, both single- and mixed-species adhered more than the L. casei (single- and mixed-species), regardless of the substrate. L. casei (single-species) formed more biofilm on the WA, but in its mixed cultivation, it had no difference of growth among the tested situations. C. albicans (single- and mixed-species) formed more biofilm on the SA than the CA, and the fungus formed more biofilm when compared to L. casei. In general, whenever a species was compared in its single- and mixed-species situation, no statistically significant difference was observed. SEM of biofilm formation assays demonstrated that L. casei single-species WA formed more biofilm than when the adhesives tested were used, and C. albicans (both single- and mixed-species) formed more biofilm on the SA than on the CA.<br><br>CONCLUSIONS: (1) The two denture adhesives tested increased the adhesion of C. albicans but not of L. casei; (2) biofilm formation by C. albicans (single- and mixed-species) was increased on the SA; (3) Relations of synergism or antagonism was not observed between the two microorganisms studied.},
}
@article {pmid30303560,
year = {2018},
author = {Busanello, FH and Petridis, X and So, MVR and Dijkstra, RJB and Prashant, SK and van der Sluis, LWM},
title = {Chemical biofilm removal capacity of endodontic irrigants as a function of biofilm structure: optical coherence tomography, confocal microscopy and viscoelasticity determination as integrated assessment tools.},
journal = {International endodontic journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/iej.13027},
pmid = {30303560},
issn = {1365-2591},
abstract = {AIM: To investigate the influence of biofilm structure on the biofilm removal capacity of endodontic irrigants and to study changes in the architecture of the remaining biofilms.<br><br>METHODOLOGY: Streptococcus oralis J22 and Actinomyces naeslundii T14V-J1 were co-cultured under different growth conditions on saliva-coated hydroxyapatite discs. A Constant Depth Film Fermenter (CDFF) was used to grow steady-state 4-day biofilms. Biofilms were grown under static conditions for 4 and 10 days within a confined space. Twenty microlitres of 2% NaOCl, 2% CHX, 17% EDTA and buffer were applied statically on the biofilms for 60 s. Biofilm removal was evaluated with Optical Coherence Tomography (OCT). Post-treated biofilms were assessed via Low Load Compression Testing (LLCT) and Confocal Laser Scanning Microscopy (CLSM). OCT data were analyzed through a two-way Analysis of Variance (ANOVA). LLCT and CLSM data were analyzed through one-way ANOVA and Dunnett's post-hoc test. The level of significance was set at a < 0.05.<br><br>RESULTS: The initial biofilm structure affected the biofilm removal capacity of the irrigants. NaOCl demonstrated the highest chemical efficacy against the biofilms and was significantly more effective on the static than the CDFF biofilms (P < 0.001). CHX was ineffective and caused a re-arrangement of the biofilm structure. EDTA exhibited a distinct removal effect only on the CDFF biofilms. Biofilm age influenced the structure of the remaining biofilms. The 4-day grown remaining biofilms had a significantly different viscoelastic pattern compared to the respective 10-day grown biofilms (P ≤ 0.01), especially in the NaOCl-treated group. CLSM analysis confirmed the CHX-induced biofilm structural re-arrangement.<br><br>CONCLUSIONS: Biofilm structure is an influential factor on the chemical efficacy of endodontic irrigants. Optical Coherence Tomography allows biofilm removal characteristics to be studies. NaOCl should remain the primary irrigant. EDTA was effective against cell-rich/ EPS-poor biofilms. CHX did not remove biofilm, but rather re-arranged its structure. This article is protected by copyright. All rights reserved.},
}
@article {pmid30300770,
year = {2018},
author = {Emerenciano, NG and Botazzo Delbem, AC and Pessan, JP and Nunes, GP and Souza Neto, FN and de Camargo, ER and Danelon, M},
title = {In situ effect of fluoride toothpaste supplemented with nano-sized sodium trimetaphosphate on enamel demineralization prevention and biofilm composition.},
journal = {Archives of oral biology},
volume = {96},
number = {},
pages = {223-229},
doi = {10.1016/j.archoralbio.2018.09.019},
pmid = {30300770},
issn = {1879-1506},
abstract = {OBJECTIVE: To evaluate the effect of a fluoride toothpaste containing nano-sized sodium trimetaphosphate (TMPnano) on enamel demineralization in situ and composition of the biofilm.<br><br>DESIGN: This crossover double-blind study consisted of four phases (seven days each) and 12 volunteers who wore oral appliances containing four enamel bovine blocks. The cariogenic challenge was performed by 30% sucrose solution (6x/day). The toothpaste treatments (3x/day) were as follows: no F/TMP/TMPnano (Placebo), 1100 ppm F (1100F), 1100F plus 3% micrometric or nano-sized TMP (1100F/TMP; 1100F/TMPnano). Percentage of surface hardness loss (%SH), and integrated loss of subsurface hardness (ΔKHN), as well as enamel calcium (Ca), phosphorus (P), and fluoride (F) were determined. Moreover, biofilm formed on the blocks were analyzed for F, Ca, P, and insoluble extracellular polysaccharide (EPS) concentrations. Data were analyzed using one-way ANOVA, repeated measures followed by Fisher LSD test (p < 0.001).<br><br>RESULTS: 1100F/TMPnano promoted the lowest %SH and ΔKHN among all groups (p < 0.001). Regarding the F concentrations in the enamel and in the biofilm, there were no significant differences between 1100 F and 1100 F/TMPnano, but significantly increased enamel Ca concentrations (p < 0.001). 1100F/TMPnano showed lower values of EPS concentration when compared with 1100F (∼80%) (p < 0.001).<br><br>CONCLUSION: 1100F/TMPnano promoted a greater protective effect against enamel demineralization and significantly affected the composition of biofilm formed in situ when compared to 1100F toothpaste.},
}
@article {pmid30299554,
year = {2018},
author = {Thompson, CM and Tischler, AH and Tarnowski, DA and Mandel, MJ and Visick, KL},
title = {Nitric oxide inhibits biofilm formation by Vibrio fischeri via the nitric oxide-sensor HnoX.},
journal = {Molecular microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mmi.14147},
pmid = {30299554},
issn = {1365-2958},
abstract = {Nitric oxide (NO) is an important defense molecule secreted by the squid Euprymna scolopes and sensed by the bacterial symbiont, Vibrio fischeri, via the NO-sensor HnoX. HnoX inhibits colonization through an unknown mechanism. The genomic location of hnoX adjacent to hahK, a recently identified positive regulator of biofilm formation, suggested that HnoX may inhibit colonization by controlling biofilm formation, a key early step in colonization. Indeed, deletion of hnoX resulted in early biofilm formation in vitro, an effect that was dependent on HahK and its putative phosphotransfer residues. An allele of hnoX that encodes a protein with increased activity severely delayed wrinkled colony formation. Control occurred at the level of transcription of the syp genes, which produce the polysaccharide matrix component. The addition of NO abrogated biofilm formation and diminished syp transcription, effects that required HnoX. Finally, an hnoX mutant formed larger symbiotic biofilms. This work has thus uncovered a host-relevant signal controlling biofilms and a mechanism for inhibition of biofilm formation by V. fischeri. The study of V. fischeri HnoX permits us to understand not only host-associated biofilm mechanisms, but also the function of HnoX domain proteins as regulators of important bacterial processes. This article is protected by copyright. All rights reserved.},
}
@article {pmid30297525,
year = {2018},
author = {Danforth, DR and Tang-Siegel, G and Ruiz, T and Mintz, KP},
title = {A non-fimbrial adhesin of Aggregatibacter actinomycetemcomitans mediates biofilm biogenesis.},
journal = {Infection and immunity},
volume = {},
number = {},
pages = {},
doi = {10.1128/IAI.00704-18},
pmid = {30297525},
issn = {1098-5522},
abstract = {Periodontitis is an inflammatory disease caused by polymicrobial biofilms. The periodontal pathogen Aggregatibacter actinomycetemcomitans displays two proteinaceous surface structures, the fimbriae and the non-fimbrial extracellular matrix binding protein A (EmaA), as observed by electron microscopy. Fimbriae participate in biofilm biogenesis and the EmaA adhesins mediate collagen binding. However, in the absence of fimbriae, A. actinomycetemcomitans still retains the potential to form robust biofilms, suggesting other surface macromolecules participate in biofilm development. Here, isogenic mutant strains lacking EmaA structures, but still expressing fimbriae, were observed to have reduced biofilm potential. In strains lacking both EmaA and fimbriae, biofilm mass was reduced by 80%. EmaA enhanced biofilm formation in different strains, independent of the fimbriation state or serotype. Confocal microscopy revealed differences in cell density within microcolonies between the EmaA positive and mutant strains. EmaA mediated biofilm formation was found to be independent of the glycosylation state and the precise 3-D conformation of the protein, and thus this function is uncorrelated with collagen binding activity. The data suggests that EmaA is a multifunctional adhesin that utilizes different mechanisms to enhance bacterial binding to collagen and to enhance biofilm formation, both of which are important for A. actinomycetemcomitans colonization and subsequent infection.},
}
@article {pmid30297365,
year = {2018},
author = {Müsken, M and Pawar, V and Schwebs, T and Bähre, H and Felgner, S and Weiss, S and Häussler, S},
title = {Breaking the vicious cycle of antibiotic killing and regrowth of biofilm-residing Pseudomonas aeruginosa.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01635-18},
pmid = {30297365},
issn = {1098-6596},
abstract = {Biofilm-residing bacteria embedded in an extracellular matrix are protected from diverse physico-chemical insults. In addition to the general recalcitrance of biofilm-bacteria, high bacterial loads in biofilm-associated infections significantly diminishes the efficacy of antimicrobials due to a low per-cell antibiotic concentration. Accordingly, present antimicrobial treatment protocols, that have been established to serve the eradication of acute infections, fail to clear biofilm-associated chronic infections. In the present study, we applied automated confocal microscopy on Pseudomonas aeruginosa to monitor dynamic killing of biofilm-grown bacteria by tobramycin and colistin in real-time. We revealed that the time required for surviving bacteria to repopulate the biofilm could be taken as measure for effectiveness of the antimicrobial treatment. It depends on the: i) nature and concentration of the antibiotic, ii) duration of antibiotic treatment; iii) application as mono or combination therapy and iv) time intervals of drug administration. The vicious cycle of killing and repopulation of biofilm bacteria could also be broken in an in vivo model system by applying successive antibiotic dosages with time intervals that do not allow full reconstitution of the biofilm communities. Treatment regimens that consider the important aspects of antimicrobial killing kinetics bear the potential to improve control of biofilm regrowth. This is an important and underestimated factor that is bound to ensure sustainable treatment success of chronic infections.},
}
@article {pmid30297364,
year = {2018},
author = {Heacock-Kang, Y and Sun, Z and Zarzycki-Siek, J and Poonsuk, K and McMillan, IA and Chuanchuen, R and Hoang, TT},
title = {Two regulators, PA3898 and PA2100, modulate the Pseudomonas aeruginosa multidrug resistance MexAB-OprM and EmrAB efflux-pumps and biofilm formation.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01459-18},
pmid = {30297364},
issn = {1098-6596},
abstract = {It is generally believed that the Pseudomonas aeruginosa biofilm matrix itself acts as a molecular sieve or sink that contributes to significant levels of drug resistance, but it is becoming more apparent that multidrug efflux-pumps induced during biofilm growth significantly enhances resistance levels. We present here a novel transcriptional regulator, PA3898, which controls biofilm formation and multidrug efflux-pumps in P. aeruginosa A mutant of this regulator significantly reduced the ability of P. aeruginosa to produce biofilm in vitro, and affected its in vivo fitness and pathogenesis in Drosophila melanogaster and BALB/c mouse lung infection models. Transcriptome analysis revealed that PA3898 modulates essential virulence genes/pathways, including multidrug efflux-pumps and phenazine biosynthesis. ChIP-seq identified its DNA binding sequences and confirmed PA3898 directly interacts with promoter regions of four genes/operons, two of which are mexAB-oprM and phz2 Co-immunoprecipitation revealed a regulatory partner of PA3898 as PA2100, and both are required for binding to DNA in electrophoresis mobility shift assays. PA3898 and PA2100 were given the names MdrR1 and MdrR2, respectively, as novel repressors of the mexAB-oprM multidrug efflux operon and activators for another multidrug efflux pump EmrAB. Interaction between MdrR1 and MdrR2 to the promoter regions of their regulons was further characterized via localized surface plasmon resonance and DNA footprinting. These regulators directly repress the mexAB-oprM operon, independent of its well-established MexR regulator. Mutants of mdrR1 and mdrR2 caused increased resistance to multiple antibiotics in P. aeruginosa, validating the significance of these newly discovered regulators.},
}
@article {pmid30296655,
year = {2018},
author = {Magi, G and Marini, E and Brenciani, A and Di Lodovico, S and Gentile, D and Ruberto, G and Cellini, L and Nostro, A and Facinelli, B and Napoli, E},
title = {Chemical composition of Pistacia vera L. oleoresin and its antibacterial, anti-virulence and anti-biofilm activities against oral streptococci, including Streptococcus mutans.},
journal = {Archives of oral biology},
volume = {96},
number = {},
pages = {208-215},
doi = {10.1016/j.archoralbio.2018.09.013},
pmid = {30296655},
issn = {1879-1506},
abstract = {OBJECTIVE: The aim of this study was to characterize the chemical composition of oleoresin of Pistacia vera L. and to determine its antimicrobial and anti-virulence activity versus selected oral streptococci.<br><br>DESIGN: A gaschromatografic analysis of the oleoresin was performed. The antimicrobial and anti-virulence activity of the oleoresin and its fractions was evaluated by the Minimum Inhibitory Concentration (MIC) and/or Minimum Bactericidal Concentration (MBC), biofilm production and haemolytic activity inhibition experiments.<br><br>RESULTS: The oleoresin MBCs were ≥1024 μg/mL for all tested strains; the neutral and acidic fraction MBCs ranged from 128 to 2048 μg/mL. Essential oil's MBCs (from 256 to 2048 μg/mL) were almost identical to MICs, suggesting a bactericidal effect. P. vera oleoresin at sub-lethal concentrations significantly reduced biofilm production by Streptococcus mutans (up to 49.4%) and by Streptococcus sanguinis (up to 71.2%). In addition, the acidic fraction showed a specific anti-biofilm activity against S. mutans (up to 41.3% reduction). A significant dose-dependent reduction in the haemolytic activity of S. mutans (up to 65.9%) and of S. anginosus (up to 78.3%) was observed after growth in the presence of oleoresin at sub-lethal concentrations. The acidic fraction reduced haemolytic activity (up to 54.3% at 64 μg/mL) of S. mutans only.<br><br>CONCLUSIONS: Given the anti-virulence activity of the P. vera oleoresin and its acidic fraction against S. mutans, our findings suggest their potential use in oral hygiene. These data represent the first step in the exploitation of P. vera L. oleoresin.},
}
@article {pmid30296552,
year = {2018},
author = {Ye, WH and Fan, B and Purcell, W and Meghil, MM and Cutler, CW and Bergeron, BE and Ma, JZ and Tay, FR and Niu, LN},
title = {Anti-biofilm efficacy of root canal irrigants against in-situ Enterococcus faecalis biofilms in root canals, isthmuses and dentinal tubules.},
journal = {Journal of dentistry},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jdent.2018.10.002},
pmid = {30296552},
issn = {1879-176X},
abstract = {OBJECTIVE: To investigate the anti-biofilm efficacy of root canal irrigants in canal spaces, isthmi and dentinal tubules of root canals ex vivo.<br><br>METHODS: Fifty-one single-rooted premolars, each containing an isthmus, were instrumented, autoclaved and inoculated with Enterococcus faecalis for 4 weeks. One specimen was sectioned for bacteria-specific staining to confirm the presence of biofilms using light microscopiy. The remaining specimens were randomly divided to five groups: (1) 0.9% NaCl, (2) SilverSol/H2O2, (3) HYBENX, (4) QMix 2 in., (5) 6% NaOCl. Bacterial sampling was performed before (S1) and after (S2) canal irrigation. Diluted bacteria suspension was cultured for 48 hours for counting the colony forming units (CFU). Percentages of dead bacteria and biofilm thickness were evaluated by confocal laser scanning microscopy (CLSM). Metabolic activity, lactic acid and polysaccharide synthesis of E. faecalis derived from S2 samples were analysed.<br><br>RESULTS: The percentages of dead bacteria were significantly affected by the factor &quot;irrigant&quot; (p < 0.001) and the factor &quot;location&quot; (p = 0.017). The percentages of dead bacteria in the isthmi and canals were both in the ordor: NaCl < SilverSol/H2O2 < HYBENX < QMix 2 in. < NaOCl (p < 0.05). Only 6% NaOCl disrupted biofilms and significantly reduced their thickness. The CFU, metabolic activity, polysaccharide and lactic acid production of E. faecalis were all reduced by the disinfecting solutions.<br><br>CONCLUSIONS: SilverSol/H2O2 and HYBENX were less adept than QMix 2 in. at killing biofilm bacteria in root canals. None of these antibacterial irrigants were effective, compared with 6% NaOCl, in disrupting biofilms.<br><br>CLINICAL SIGNIFICANCE: There is advantage in using HYBENX or QMix 2 in. to kill intratubular bacteria biofilms because of their capability in removing the inorganic component of the smear layer. SilverSol/H2O2 requires extra time to eradicate intratubular biofilms upon removal of the organic and inorganic components of the smear layer by other root canal irrigants.},
}
@article {pmid30296253,
year = {2018},
author = {Zarnowski, R and Sanchez, H and Covelli, AS and Dominguez, E and Jaromin, A and Berhardt, J and Heiss, C and Azadi, P and Mitchell, A and Andes, DR},
title = {Candida albicans biofilm-induced vesicles confer drug resistance through matrix biogenesis.},
journal = {PLoS biology},
volume = {16},
number = {10},
pages = {e2006872},
doi = {10.1371/journal.pbio.2006872},
pmid = {30296253},
issn = {1545-7885},
abstract = {Cells from all kingdoms of life produce extracellular vesicles (EVs). Their cargo is protected from the environment by the surrounding lipid bilayer. EVs from many organisms have been shown to function in cell-cell communication, relaying signals that impact metazoan development, microbial quorum sensing, and pathogenic host-microbe interactions. Here, we have investigated the production and functional activities of EVs in a surface-associated microbial community or biofilm of the fungal pathogen Candida albicans. Crowded communities like biofilms are a context in which EVs are likely to function. Biofilms are noteworthy because they are encased in an extracellular polymeric matrix and because biofilm cells exhibit extreme tolerance to antimicrobial compounds. We found that biofilm EVs are distinct from those produced by free-living planktonic cells and display strong parallels in composition to biofilm matrix material. The functions of biofilm EVs were delineated with a panel of mutants defective in orthologs of endosomal sorting complexes required for transport (ESCRT) subunits, which are required for normal EV production in diverse eukaryotes. Most ESCRT-defective mutations caused reduced biofilm EV production, reduced matrix polysaccharide levels, and greatly increased sensitivity to the antifungal drug fluconazole. Matrix accumulation and drug hypersensitivity of ESCRT mutants were reversed by addition of wild-type (WT) biofilm EVs. Vesicle complementation showed that biofilm EV function derives from specific cargo proteins. Our studies indicate that C. albicans biofilm EVs have a pivotal role in matrix production and biofilm drug resistance. Biofilm matrix synthesis is a community enterprise; prior studies of mixed cell biofilms have demonstrated extracellular complementation. Therefore, EVs function not only in cell-cell communication but also in the sharing of microbial community resources.},
}
@article {pmid30295328,
year = {2018},
author = {Swimberghe, RCD and De Clercq, A and De Moor, RJG and Meire, MA},
title = {Efficacy of sonically, ultrasonically and laser-activated irrigation in removing a biofilm-mimicking hydrogel from an isthmus model.},
journal = {International endodontic journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/iej.13024},
pmid = {30295328},
issn = {1365-2591},
abstract = {AIM: To evaluate the efficacy of sonically, ultrasonically, and laser-activated irrigation in removing a biofilm-mimicking hydrogel from the isthmus in a root canal model.<br><br>METHODOLOGY: Transparent resin blocks containing 2 standardized root canals (apical diameter of 0.3 mm, 6% taper, 16 mm long, with a coronal reservoir) connected by an isthmus (0.15 mm wide, 2 mm high) were used as the test model. The isthmus was filled with a hydrogel containing dentine debris. The canals were filled with irrigant, and the models were randomly assigned to the following activation groups (n=20): EndoActivator (EA), Eddy, ultrasonically activated irrigation with an Irrisafe 25 mm length, size 25 file (UAI), and laser-activated irrigation (LAI) with a 2940 nm Er:YAG-laser (20 Hz, 50 μs, 20 mJ, PIPS tip at the canal entrance). All protocols were executed for 3 x 20 s. Needle irrigation (NI) with a 27G needle served as the control. Standardized images of the isthmus were taken before and after irrigation, and the amount of removed hydrogel was determined using image analysis software and compared across groups using Welch ANOVA (P ≤ 0.05).<br><br>RESULTS: Hydrogel removal was highest in the LAI group (90.2%), and was significantly higher than that with UAI, EA, and NI (P ≤ 0.014), but not significantly different from Eddy (P = 0.498). Hydrogel removal with Eddy (85.9%) was significantly higher than that with NI and EA (P < 0.05), but not significantly different from UAI (P = 0.07). There was no significant difference between the NI and EA group (P = 1).<br><br>CONCLUSIONS: Laser-activated irrigation and Eddy resulted in the greatest hydrogel removal, and performed better than EndoActivator and ultrasonically activated irrigation. The effect of laser-activated irrigation was also not dependent on deep intracanal tip placement. This article is protected by copyright. All rights reserved.},
}
@article {pmid30295162,
year = {2018},
author = {Ali, Q},
title = {Non-conventional therapeutic technique to replace CRISPR bacteria from biofilm by inducible lysogen.},
journal = {Journal of biological dynamics},
volume = {},
number = {},
pages = {1-28},
doi = {10.1080/17513758.2018.1527958},
pmid = {30295162},
issn = {1751-3766},
abstract = {Bacteriophage can be an effective means of regulating bacterial populations when conditions allow phage invasion of bacterial colonies. Phage can either infect and lyse a host cell, or insert their DNA into the host cell genome; the latter process is called lysogeny. The clustered regularly interspaced short palindromic repeat (CRISPR) system, linked with CRISPR-associated (Cas) genes, is a regulatory system present in a variety of bacteria which confers immunity against bacteriophage. Studies of the group behaviour of bacteria with CRISPR/Cas systems have provided evidence that CRISPR in lysogenized bacteria can cause an inability to form biofilm. This allows CRISPR-immune bacteria in biofilms to effectively resist phage therapy. Our recent work has described a potential therapeutic technique to eradicate CRISPR-immune bacteria from a biofilm by a continuous influx of lysogens carrying an identical phage sequence. However, this model predicted that the CRISPR-immune population could persist for long times before eradication. Our current focus is on the use of diverse lysogens against CRISPR-capable bacterial populations. The goal of this work is to find a suitable strategy which can eradicate bacteria with a CRISPR system through the influx of finite amounts of distinct lysogens over fixed intervals.},
}
@article {pmid30292821,
year = {2018},
author = {Pickering, DS and Wilcox, MH and Chilton, CH},
title = {Biofilm-derived spores of Clostridioides (Clostridium) difficile exhibit increased thermotolerance compared to planktonic spores.},
journal = {Anaerobe},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.anaerobe.2018.10.003},
pmid = {30292821},
issn = {1095-8274},
abstract = {Biofilm-derived spores of strains of four ribotypes (001, 020, 027 &amp; 078) of Clostridioides (Clostridium) difficile were found to exhibit increased thermotolerance compared to spores produced in planktonic culture. In addition, 'thick' and 'thin' exosporium morphotypes described previously were visualised by electron microscopy in both biofilm and planktonic spores.},
}
@article {pmid30292689,
year = {2018},
author = {Jiang, Y and Zeng, RJ},
title = {Bidirectional extracellular electron transfers of electrode-biofilm: Mechanism and application.},
journal = {Bioresource technology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.biortech.2018.09.133},
pmid = {30292689},
issn = {1873-2976},
abstract = {The extracellular electron transfer (EET) between microorganisms and electrodes forms the basis for microbial electrochemical technology (MET), which recently have advanced as a flexible platform for applications in energy and environmental science. This review, for the first time, focuses on the electrode-biofilm capable of bidirectional EET, where the electrochemically active bacteria (EAB) can conduct both the outward EET (from EAB to electrodes) and the inward EET (from electrodes to EAB). Only few microorganisms are tested in pure culture with the capability of bidirectional EET, however, the mixed culture based bidirectional EET offers great prospects for biocathode enrichment, pollutant complete mineralization, biotemplated material development, pH stabilization, and bioelectronic device design. Future efforts are necessary to identify more EAB capable of the bidirectional EET, to balance the current density, to evaluate the effectiveness of polarity reversal for biocathode enrichment, and to boost the future research endeavors of such a novel function.},
}
@article {pmid30292385,
year = {2018},
author = {Heidari, H and Hadadi, M and Sedigh Ebrahim-Saraie, H and Mirzaei, A and Taji, A and Hosseini, SR and Motamedifar, M},
title = {Characterization of virulence factors, antimicrobial resistance patterns and biofilm formation of Pseudomonas aeruginosa and Staphylococcus spp. strains isolated from corneal infection.},
journal = {Journal francais d'ophtalmologie},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jfo.2018.01.012},
pmid = {30292385},
issn = {1773-0597},
abstract = {INTRODUCTION: Infectious keratitis is a serious ocular infection that can lead to severe visual impairment and blindness. Bacterial pathogens are responsible for nearly half of infectious keratitis cases. This study was performed to determine the virulence factors, antimicrobial resistance patterns, and biofilm formation ability of Pseudomonas aeruginosa and Staphylococcus spp. strains isolated from corneal infections.<br><br>METHODS: A total of 56 corneal scraping samples were collected over 8 months. P. aeruginosa and staphylococcal strains were identified by phenotypic and genotypic methods. Determination of multidrug resistance was performed according to its definition of multidrug resistance (MDR). Detection of antimicrobial resistance genes and determinants of virulence were also performed using standard procedures. Biofilm formation ability of the isolates was determined by colorimetric microtitration plate assay and Modified Congo red agar (MCRA).<br><br>RESULTS: In the present study, P. aeruginosa, MSSA, MRSA, MS-CoNS and MR-CoNS strains were isolated from corneal infections. Multidrug resistance was observed in 42.9% and 57.1% of P. aeruginosa and Staphylococcus spp., respectively. The most frequent virulence genes among P. aeruginosa strains were exoA and exoS (100%) followed by exoU (71.4%) and lasB (28.6%). All the P. aeruginosa isolates were biofilm producers and carried the algD gene (100%). All staphylococcal strains were negative for pvl gene amplification. Biofilm formation was also observed in 4 (57.1%) isolates. Both icaA and icaD genes were detected in the biofilm producers.<br><br>CONCLUSION: Our results indicated that P. aeruginosa and Staphylococcus spp. were the most prevalent bacterial agents that cause corneal infections. However, their virulence traits and biofilm formation ability were noteworthy.},
}
@article {pmid30291415,
year = {2018},
author = {Zhai, S and Zhao, Y and Ji, M and Qi, W},
title = {A dicyclic-type electrode-based biofilm reactor for simultaneous nitrate and Cr(VI) reduction.},
journal = {Bioprocess and biosystems engineering},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00449-018-2020-2},
pmid = {30291415},
issn = {1615-7605},
support = {Project No. 21507101, China//National Natural Science Foundation of China/ ; Project No.15JCQNJC08700, China//Tianjin Research Program of Application Foundation and Advanced Technology/ ; },
abstract = {A dicyclic-type electrode-based biofilm-electrode reactor (BER) was investigated for simultaneous removal of nitrate and Cr(VI). In the absence of Cr(VI), almost complete denitrification of 50 mg/L NO3--N was achieved at a very low C/N ratio of 0.8 with the optimal current of 50 mA. Cr(VI) was removed by biological reduction and co-precipitation when Cr(VI) was taken as the only electron acceptor, and the removal efficiencies of Cr(VI) were 99.8%. In the coexistent system of nitrate and Cr(VI), nitrate removal was the result of the cooperation of hydrogenotrophic denitrification and heterotrophic denitrification. The methanol and H2 were also used as electron donors for biological reduction Cr(VI). The denitrification process was slightly inhibited by 1.00 mg/L Cr(VI) and 94.15% removal efficiency was achieved at current = 50 mA and HRT = 8 h. The present results show that the biofilm-electrode reactor is an effective way to simultaneous remove co-contaminants.},
}
@article {pmid30291231,
year = {2018},
author = {Chu, EK and Kilic, O and Cho, H and Groisman, A and Levchenko, A},
title = {Self-induced mechanical stress can trigger biofilm formation in uropathogenic Escherichia coli.},
journal = {Nature communications},
volume = {9},
number = {1},
pages = {4087},
doi = {10.1038/s41467-018-06552-z},
pmid = {30291231},
issn = {2041-1723},
abstract = {Bacterial biofilms represent an important medical problem; however, the mechanisms of the onset of biofilm formation are poorly understood. Here, using new controlled methods allowing high-throughput and reproducible biofilm growth, we show that biofilm formation is linked to self-imposed mechanical stress. In growing uropathogenic Escherichia coli colonies, we report that mechanical stress can initially emerge from the physical stress accompanying colony confinement within micro-cavities or hydrogel environments reminiscent of the cytosol of host cells. Biofilm formation can then be enhanced by a nutrient access-modulated feedback loop, in which biofilm matrix deposition can be particularly high in areas of increased mechanical and biological stress, with the deposited matrix further enhancing the stress levels. This feedback regulation can lead to adaptive and diverse biofilm formation guided by the environmental stresses. Our results suggest previously unappreciated mechanisms of the onset and progression of biofilm growth.},
}
@article {pmid30291117,
year = {2018},
author = {Oxaran, V and Dittmann, KK and Lee, SHI and Chaul, LT and de Oliveira, CAF and Corassin, CH and Alves, VF and De Martinis, ECP and Gram, L},
title = {Behavior of foodborne pathogens, Listeria monocytogenes and Staphylococcus aureus, in mixed-species biofilm exposed to biocides.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.02038-18},
pmid = {30291117},
issn = {1098-5336},
abstract = {In nature and man-made environments, microorganisms reside in mixed-species biofilm where behavior is modified compared to the single-species biofilms. Pathogenic microorganisms may be protected against adverse treatments in mixed-species biofilms leading to health risk for humans. Here, we developed two mixed-five-species biofilms that included the foodborne pathogens Listeria monocytogenes or Staphylococcus aureus, respectively. The five species, including the pathogen, were isolated from a single food-processing environmental sample thus mimicking the environmental community. In mature mixed five-species biofilms on stainless steel, the two pathogens remained at a constant level of ∼105 CFU/cm2 The mixed-five-species biofilms as well as the pathogens in mono-species biofilms were exposed to biocides to determine any pathogen-protective effect of the mixed biofilm. Both pathogens and their associate microbial communities were reduced by peracetic acid treatments. S. aureus decreased 4.6 log cycles in mono-species biofilm, but the pathogen was protected in the five-species biofilm and decreased only 1.1 log cycles. Sessile cells of L. monocytogenes were affected equally as a mono-biofilm or as a member in the mixed-species biofilm; decreasing by three log cycles when exposed to 0.0375 % peracetic acid. When the pathogen was exchanged in each associate microbial community, S. aureus was eradicated while there was no significant effect of the biocide on L. monocytogenes or the mixed community. This indicates that particular members or associations in the community offered the protective effect. Further studies are needed to clarify the mechanisms of biocide protection, and the species playing the protective role in microbial communities of biofilms.Importance This study demonstrates that foodborne pathogens can be established in mixed species biofilms and that this can protect them from biocide action. The protection is not due to specific characteristics of the pathogen, here S. aureus and L. monocytogenes, but likely caused by specific members or associations in the mixed species biofilm. Biocide treatment and resistance is a challenge for many industries and biocide efficacy should be tested on microorganisms growing in biofilms, preferably mixed systems, mimicking the application environment.},
}
@article {pmid30290269,
year = {2018},
author = {Mizdal, CR and Stefanello, ST and Nogara, PA and Antunes Soares, FA and de Lourenço Marques, L and de Campos, MMA},
title = {Molecular docking, and anti-biofilm activity of gold-complexed sulfonamides on Pseudomonas aeruginosa.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2018.10.004},
pmid = {30290269},
issn = {1096-1208},
abstract = {The antibacterial activity of sulfadiazine Au-PPh3, sulfadiazine Ph2P-Au-Au-PPh2, sulfamethoxazole Au-PPh3, sulfamethoxazole Ph2P-Au-Au-PPh2, sulfamethoxazole Au-PPh3 were tested against Pseudomonas aeruginosa. The antibacterial activity of sulfonamide was tested against P. aeruginosa through the MIC assay, quantitative analysis of biofilm inhibition and observation of biofilm formation with fluorescence microscopy. Besides, the compounds presented remarkable inhibition of P. aeruginosa biofilm formation. Furthermore, molecular docking was performed to identify the key structural features of these compounds with the binding site of the LasR receptor.},
}
@article {pmid30290265,
year = {2018},
author = {Sharma, D and Khan, AU},
title = {Role of cell division protein divIVA in Enterococcus faecalis pathogenesis, biofilm and drug resistance: A future perspective by in silico approaches.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2018.10.001},
pmid = {30290265},
issn = {1096-1208},
abstract = {Antibiotics resistance is the major problem in clinical settings which leads to the emergence of drug resistant bacteria. Biofilm formation is one of the grounds for the emergence of antibiotics resistant strains of Enterococcus faecalis. Our group previously reported in a comparative proteomic study of biofilm and planktonic state of E. faecalis that cell division protein divIVA was two folds overexpressed in biofilm state as compared to planktonic one and suggested its involvement in biofilm formation and antibiotics resistance. In this in silico study molecular docking showed that DNA bind to the conserved amino acid residues of divIVA domain and suggested that divIVA possibly secretes DNA into extra polymeric substance (EPS) which is the part of biofilm. We also performed the STRING analysis of cell division protein divIVA and predicted their interactive partners {cell division proteins/divisome complex (ftsZ, ftsA, divIV, ftsL, &amp; gpsB), hypothetical proteins (sepF, EF_0261, EF_1000, EF_0998, EF_1006 &amp; EF_1040), isoleucyl-tRNA synthetase (ileS), septation ring formation regulator (ezrA), S4 domain-containing protein (EF_1001), rod shape-determining protein (mreC), UDP-N-acetylmuramoyl-L-alanyl-d-glutamate synthetase (murD), UDP-diphospho-muramoyl-pentapeptide beta-N- acetylglucosaminyltransferase (murG), Lipoprotein signal peptidase (lspA), adenylate kinase (adk) and DNA-binding response regulator (vicR)}
. We suggest that cumulatively divIVA and its interactive partners might be directly or indirectly involved in E. faecalis cell division, growth, biofilm formation, virulence and resistance.},
}
@article {pmid30288586,
year = {2018},
author = {Kang, J and Liu, L and Wu, X and Sun, Y and Liu, Z},
title = {Effect of thyme essential oil against Bacillus cereus planktonic growth and biofilm formation.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-018-9401-y},
pmid = {30288586},
issn = {1432-0614},
support = {31301472//National Natural Science Foundations of China/ ; },
abstract = {The objective of this study was to determine the effect of thyme essential oil (TEO) on the planktonic growth and biofilm formation of Bacillus cereus (B. cereus). GC-MS analysis of TEO allowed the detection of 13 compounds, and the major constituents were p-cymene (29.7%), thymol (23.73%), γ-terpinene (16.21%), and 1,8-cineole (9.74%). TEO exhibited a minimum inhibitory concentration (MIC) value against planktonic B. cereus of 0.25 mg/mL. The potent effect of TEO to inhibit the growth of planktonic B. cereus was due to cell membrane damage, as evidenced by reduced cell viability, protein changes, decreased intracellular ATP concentration, increased extracellular ATP concentration and cell membrane depolarization, and cellular morphological changes. In addition, TEO exerted a significant inhibitory effect on B. cereus biofilm formation, as confirmed by environmental scanning electron microscopic images. These findings suggested that TEO has the potential to be developed as a natural food additive to control foodborne contamination associated with B. cereus and its biofilm.},
}
@article {pmid30288179,
year = {2018},
author = {Parrino, B and Diana, P and Cirrincione, G and Cascioferro, S},
title = {Bacterial Biofilm Inhibition in the Development of Effective Anti-Virulence Strategy.},
journal = {The open medicinal chemistry journal},
volume = {12},
number = {},
pages = {84-87},
doi = {10.2174/1874104501812010084},
pmid = {30288179},
issn = {1874-1045},
}
@article {pmid30283433,
year = {2018},
author = {Dobay, O and Laub, K and Stercz, B and Kéri, A and Balázs, B and Tóthpál, A and Kardos, S and Jaikumpun, P and Ruksakiet, K and Quinton, PM and Zsembery, Á},
title = {Bicarbonate Inhibits Bacterial Growth and Biofilm Formation of Prevalent Cystic Fibrosis Pathogens.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {2245},
doi = {10.3389/fmicb.2018.02245},
pmid = {30283433},
issn = {1664-302X},
abstract = {We investigated the effects of bicarbonate on the growth of several different bacteria as well as its effects on biofilm formation and intracellular cAMP concentration in Pseudomonas aeruginosa. Biofilm formation was examined in 96-well plates, with or without bicarbonate. The cAMP production of bacteria was measured by a commercial assay kit. We found that NaHCO3 (100 mmol l-1) significantly inhibited, whereas NaCl (100 mmol l-1) did not influence the growth of planktonic bacteria. MIC and MBC measurements indicated that the effect of HCO 3 - is bacteriostatic rather than bactericidal. Moreover, NaHCO3 prevented biofilm formation as a function of concentration. Bicarbonate and alkalinization of external pH induced a significant increase in intracellular cAMP levels. In conclusion, HCO 3 - impedes the planktonic growth of different bacteria and impedes biofilm formation by P. aeruginosa that is associated with increased intracellular cAMP production. These findings suggest that aerosol inhalation therapy with HCO 3 - solutions may help improve respiratory hygiene in patients with cystic fibrosis and possibly other chronically infected lung diseases.},
}
@article {pmid30281855,
year = {2018},
author = {Li, B and Maezato, Y and Kim, SH and Kurihara, S and Liang, J and Michael, AJ},
title = {Polyamine-independent growth and biofilm formation, and functional spermidine/spermine N-acetyltransferases in Staphylococcus aureus and Enterococcus faecalis.},
journal = {Molecular microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mmi.14145},
pmid = {30281855},
issn = {1365-2958},
abstract = {Polyamines such as spermidine and spermine are primordial polycations that are ubiquitously present in the three domains of life. We have found that Gram-positive bacteria Staphylococcus aureus and Enterococcus faecalis have lost either all or most polyamine biosynthetic genes, respectively, and are devoid of any polyamine when grown in polyamine-free media. In contrast to bacteria such as Pseudomonas aeruginosa, Campylobacter jejuni and Agrobacterium tumefaciens, which absolutely require polyamines for growth, S. aureus and E. faecalis grow normally over multiple subcultures in the absence of polyamines. Furthermore, S. aureus and E. faecalis form biofilms normally without polyamines, and exogenous polyamines do not stimulate growth or biofilm formation. High levels of external polyamines, including norspermidine, eventually inhibit biofilm formation through inhibition of planktonic growth. We show that spermidine/spermine N-acetyltransferase (SSAT) homologues encoded by S. aureus USA300 and E. faecalis acetylate spermidine, spermine and norspermidine, that spermine is the more preferred substrate, and that E. faecalis SSAT is almost as efficient as human SSAT with spermine as substrate. The polyamine auxotrophy, polyamine-independent growth and biofilm formation, and presence of functional polyamine N-acetyltransferases in S. aureus and E. faecalis represent a new paradigm for bacterial polyamine biology. This article is protected by copyright. All rights reserved.},
}
@article {pmid30280048,
year = {2018},
author = {Mancuso, R and Chinnici, J and Tsou, C and Busarajan, S and Munnangi, R and Maddi, A},
title = {Functions of Candida albicans cell wall glycosidases Dfg5p and Dcw1p in biofilm formation and HOG MAPK pathway.},
journal = {PeerJ},
volume = {6},
number = {},
pages = {e5685},
doi = {10.7717/peerj.5685},
pmid = {30280048},
issn = {2167-8359},
abstract = {Background: Candida albicans is a commensal fungus that inhabits the oral mucosal surface and causes oral and systemic candidiasis. Oral candidiasis most commonly occurs in patients with AIDS, denture wearers and newborn children. Systemic candidiasis occurs mainly in immunocompromised patients and patients admitted to hospitals for prolonged periods. C. albicans homologous genes, DFG5 and DCW1, encode for two closely related cell wall proteins with putative glycosyltransferase enzyme activity and C-terminal GPI-anchors. Past studies have shown that individual DFG5 and DCW1 mutations are viable but simultaneous deletion of DFG5 and DCW1 in C. albicans results in lethality. However, the exact functions of these cell wall based enzymes, which represent potential drug targets, are not understood.<br><br>Methods: C. albicans DFG5/DCW1 heterologous and conditional double mutant strains were assessed for growth and biofilm formation in comparison to wild type and parental strains. Cell wall and heat stress susceptibility of the mutant and control strains were assessed using agar spotting assays. Growth was assessed under normal and osmotic stress conditions along with light microscopy imaging. Biofilm dry weight and microscopic imaging analysis of biofilms was performed. Hypha formation in response to serum was analyzed using light microscopy imaging. Western blot analysis of mutant strains and control strains was performed to assess Hog1 basal levels and phosphorylation status.<br><br>Results: Analysis of the heterologous mutants indicated that Dfg5p is more important for growth while Dcw1p appeared to play a role in cell wall integrity response. The conditional double mutant was observed to be less resistant to cell wall stress. However, growth of the mutants was similar under control and osmotic stress conditions. The mutants were also able to grow similar to wild type under heat stress. Biofilm formation was reduced in the mutants where DFG5 was deleted or suppressed. Hyphal morphogenesis was reduced although germ tube formation was observed in the biofilms of the mutant strains. Basal Hog1 protein levels were reduced or absent in the DFG5 and DCW1 mutants. However, osmotic stress was able to induce Hog1 protein levels comparable to wild type. Hog1 phosphorylation appeared to be slightly reduced although not significantly. In addition to biofilm assays, serum dose response imaging analysis indicated that hyphae formation in DFG5 and DCW1 mutants was defective.<br><br>Conclusions: These data indicate that DFG5 and DCW1 are required for hyphal morphogenesis and biofilm formation in C. albicans. These functions may be regulated via basal Hog1 MAPK which is required for transcriptional regulation of chitin synthesis.},
}
@article {pmid30279343,
year = {2018},
author = {Marc, G and Araniciu, C and Oniga, SD and Vlase, L and Pîrnău, A and Duma, M and Măruțescu, L and Chifiriuc, MC and Oniga, O},
title = {New N-(oxazolylmethyl)-thiazolidinedione Active against Candida albicans Biofilm: Potential Als Proteins Inhibitors.},
journal = {Molecules (Basel, Switzerland)},
volume = {23},
number = {10},
pages = {},
doi = {10.3390/molecules23102522},
pmid = {30279343},
issn = {1420-3049},
support = {PCD 7690/68/15.04.2016//&quot;Iuliu Hatieganu&quot; University of Medicine and Pharmacy Cluj-Napoca, Romania/ ; PCD 5200/59/01.03.2017//&quot;Iuliu Hatieganu&quot; University of Medicine and Pharmacy Cluj-Napoca, Romania/ ; PCD 3067/4/01.02.2018//&quot;Iuliu Hatieganu&quot; University of Medicine and Pharmacy Cluj-Napoca, Romania/ ; },
abstract = {C. albicans is the most frequently occurring fungal pathogen, and is becoming an increasing public health problem, especially in the context of increased microbial resistance. This opportunistic pathogen is characterized by a versatility explained mainly by its ability to form complex biofilm structures that lead to enhanced virulence and antibiotic resistance. In this context, a review of the known C. albicans biofilm formation inhibitors were performed and a new N-(oxazolylmethyl)-thiazolidinedione scaffold was constructed. 16 new compounds were synthesized and characterized in order to confirm their proposed structures. A general antimicrobial screening against Gram-positive and Gram-negative bacteria, as well as fungi, was performed and revealed that the compounds do not have direct antimicrobial activity. The anti-biofilm activity evaluation confirmed the compounds act as selective inhibitors of C. albicans biofilm formation. In an effort to substantiate this biologic profile, we used in silico investigations which suggest that the compounds could act by binding, and thus obstructing the functions of, the C. albicans Als surface proteins, especially Als1, Als3, Als5 and Als6. Considering the well documented role of Als1 and Als3 in biofilm formation, our new class of compounds that target these proteins could represent a new approach in C. albicans infection prevention and management.},
}
@article {pmid30279094,
year = {2018},
author = {Hu, J and Zhang, H and Zhou, S and Li, W and He, ZG},
title = {Characterization of a novel regulatory pathway for mannitol metabolism and its coordination with biofilm formation in Mycobacterium smegmatis.},
journal = {Journal of genetics and genomics = Yi chuan xue bao},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jgg.2018.06.007},
pmid = {30279094},
issn = {1673-8527},
abstract = {Biofilm formation has been implicated to be tightly regulated in bacteria. Mycobacterial species possess a unique cell-wall structure; however, the underlying regulation mechanism for their biofilm formation remains largely unclear. In this study, we characterized a hypothetical mannitol metabolism and transportation gene cluster (Ms5571-Ms5576), designated as mmt operon, whose expression significantly contributes to the biofilm formation in Mycobacterium smegmatis. We showed that in the operon the Ms5575 gene encodes a GntR-like transcriptional repressor and the Ms5576 gene encodes a mannitol 2-dehydrogenase which can produce D-mannitol from D-mannose. Strikingly, the D-mannitol molecule can derepress the negative regulation of Ms5575 on the mmt operon to stimulate the operon's expression. Consistently, addition of D-mannitol into the medium can obviously induce mycobacterial biofilm formation. Furthermore, we found that Ms0179 positively regulates the mmt operon through its downstream regulator Ms0180. Ms0180 directly binds the mmt operon to positively regulate its expression. Both Ms0179 and Ms0180 significantly affect the mycobacterial biofilm formation. Taken together, we explored a regulatory pathway for the mannitol metabolism and its coordination with the biofilm formation in M. smegmatis. This finding provides novel insights into the unique mechanism of biofilm formation regulation in mycobacteria.},
}
@article {pmid30278362,
year = {2018},
author = {Li, S and Li, L and Qu, Q and Kang, Y and Zhu, B and Yu, D and Huang, R},
title = {Extracellular electron transfer of Bacillus cereus biofilm and its effect on the corrosion behaviour of 316L stainless steel.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {173},
number = {},
pages = {139-147},
doi = {10.1016/j.colsurfb.2018.09.059},
pmid = {30278362},
issn = {1873-4367},
abstract = {Here, a heterogeneous Bacillus cereus (B. cereus) biofilm on the surface of 316 L stainless steel (SS) was observed. With electrochemical measurement and surface analysis, it was found that B. cereus biofilm could inhibit SS pitting corrosion, attributing to the blocking effect of bacterial biofilm on extracellular electron transfer (EET). Differential pulse voltammetry (DPV) and cyclic voltammetry (CV) results also showed that B. cereus biofilm clearly impeded the EET. The proposed mechanism for the decreased corrosion rates of SS involves the interactions of extracellular polymeric substance (EPS) with SS and biofilm formation blocking electron transfer, preventing the passive layer from destroying. After biofilm formation following initial attachment of cells and EPS, electron transfer between SS and the cathodic depolarizer (oxygen) was hindered.},
}
@article {pmid30278278,
year = {2018},
author = {Ghaffari, S and Sarp, ASK and Lange, D and Gülsoy, M},
title = {Potassium Iodide Potentiated Photodynamic Inactivation of Enterococcus faecalis Using Toluidine Blue: Comparative Analysis and post-treatment Biofilm Formation Study.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2018.09.019},
pmid = {30278278},
issn = {1873-1597},
abstract = {BACKGROUND: Photodynamic Inactivation (PDI) has recently gained interest as an alternative modality to fight pathogenic entities and its effect can be further enhanced by using certain inorganic salts. Here, the Potassium Iodide (KI)-mediated PDI effect on Enterococcus faecalis using Toluidine Blue Ortho (TBO) as photosensitizer (PS) has been evaluated, and subsequent Biofilm formation extent is accounted for.<br><br>METHODS: The comparative photoinactivation of TBO and TBO/KI on E.faecalis was investigated by quantifying surviving bacterial colonies after laser irradiation with 30,60, and 180 second exposure times and different PS/Potentiator concentrations. The biofilm formation capability of E.faecalis was observed by calculating Optical Density (OD595) of samples 24,48, and 72 hours post-PDI treatment. Scanning Electron Microscopy (SEM) was used as a qualitative measure of bacterial biofilm growth.<br><br>RESULTS: More than 4 LOGS of photokilling was obtained for experimental groups with the highest PS/KI concentrations at 180 s exposure time. All KI-potentiated groups showed enhancement in PDI effect when compared to non-potentiated counterparts. The degree of recurring biofilm for laser-treated groups also showed to be much less than that of control group, as confirmed by both OD595 measurement and SEM imaging.},
}
@article {pmid30278277,
year = {2018},
author = {Pourhajibagher, M and Kazemian, H and Chiniforush, N and Hosseini, N and Pourakbari, B and Azizollahi, A and Rezaei, F and Bahador, A},
title = {Exploring different photosensitizers to optimize elimination of planktonic and biofilm forms of Enterococcus faecalis from infected root canal during antimicrobial photodynamic therapy.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2018.09.014},
pmid = {30278277},
issn = {1873-1597},
abstract = {BACKGROUND: Despite the high success rate of endodontic treatment, failure may occur in some cases. In this case, Enterococcus faecalis is the most common species in endodontic treatment failure and post-treatment apical periodontitis. Therefore, a new adjunctive strategy is needed for the prevention of endodontic infections due to E. faecalis. The aim of the present study was to compare the antimicrobial and anti-biofilm activities of different common photosensitizers (PSs) for use in antimicrobial photodynamic therapy (aPDT) against E. faecalis.<br><br>MATERIALS AND METHODS: E. faecalis strain ATCC 29212 was used as the tested strain and methylene blue (MB), toluidine blue O (TBO), indocyanine green (ICG), and curcumin (CUR) were used as PSs. Irradiation was carried out using diode laser and light emitting diode (LED) at wavelengths related to the above PSs. Then, antimicrobial and anti-biofilm activities were measured using the microbial viability assay and crystal violet test, respectively.<br><br>RESULTS: aPDT with using the above PSs significantly decreased the CFU/mL count of E. faecalis compared to the control group (P < 0.05). The killing percentage of E. faecalis via PS mediated aPDT was 99.6%, 98.2%, 85.1%, and 65.0% for CUR, ICG, TBO, and MB, respectively. aPDT using the above PSs significantly decreased the biofilm formation ability of E. faecalis compared to the control group (P < 0.05). The biofilm reduction percentage of the PSs was 68.4%, 62.9%, 59.0%, and 47.6% for CUR, ICG, TBO, and MB, respectively.<br><br>CONCLUSION: CUR and ICG mediated aPDT exhibited considerably more antimicrobial activity than other PSs, while TBO and MB demonstrated weaker anti-biofilm effects against E. faecalis compared to other PSs.},
}
@article {pmid30276456,
year = {2018},
author = {James, GA and Boegli, L and Hancock, J and Bowersock, L and Parker, A and Kinney, BM},
title = {Bacterial Adhesion and Biofilm Formation on Textured Breast Implant Shell Materials.},
journal = {Aesthetic plastic surgery},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00266-018-1234-7},
pmid = {30276456},
issn = {1432-5241},
support = {111//Establishment Labs/ ; },
abstract = {BACKGROUND: Bacterial biofilms have been implicated with breast implant complications including capsular contracture and anaplastic large-cell lymphoma. The actual mechanisms for either are still under active investigation and are not clear. Due to their increased surface area, implants with textured surfaces may harbor greater biofilm loads than those with smooth surfaces.<br><br>METHODS: Biofilm formation on the outer surface material was compared using implants with various surface areas and roughness, including Natrelle® (Smooth), SmoothSilk®/SilkSurface® (Silk), VelvetSurface ® (Velvet), Siltex®, and Biocell®. The roughness and surface area of each material were assessed using non-contact profilometry. Bacterial attachment (2 h) and biofilm formation (24 h) were evaluated for Staphylococcus epidermidis, Pseudomonas aeruginosa, and Ralstonia pickettii over nine independent experiments using a CDC biofilm reactor and viable plate counts (VPCs) as well as confocal scanning laser microscopy. VPCs of the textured implants were compared relative to the Smooth implant.<br><br>RESULTS: Surface areas increased with roughness and were similar among the three least rough implants (Smooth, Silk, and Velvet) and among the roughest implants (Siltex and Biocell). Overall, VPC indicated there was significantly more bacterial attachment and biofilm formation on the Siltex and Biocell implants than the Silk or Velvet implants, although there were differences between species and time points. CSLM confirmed the formation of thicker biofilms on the implants with rougher surface textures.<br><br>CONCLUSION: This in vitro study confirmed that implant surfaces with rougher texture, resulting in more surface area, harbored greater biofilm loads than those with smoother surfaces.<br><br>NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .},
}
@article {pmid30275239,
year = {2018},
author = {Suriyanarayanan, T and Qingsong, L and Kwang, LT and Mun, LY and Truong, T and Seneviratne, CJ},
title = {Correction: Quantitative proteomics of strong and weak biofilm formers of Enterococcus faecalis reveals novel regulators of biofilm formation.},
journal = {Molecular &amp; cellular proteomics : MCP},
volume = {17},
number = {10},
pages = {2081},
doi = {10.1074/mcp.AAC118.001077},
pmid = {30275239},
issn = {1535-9484},
}
@article {pmid30274028,
year = {2018},
author = {Roshani-Asl, P and Rashidi, N and Shokoohizadeh, L and Zarei, J},
title = {Relationship Among Antibiotic Resistance, Biofilm Formation and lasB Gene in Pseudomonas Aeruginosa Isolated from Burn Patients.},
journal = {Clinical laboratory},
volume = {64},
number = {9},
pages = {1477-1484},
pmid = {30274028},
issn = {1433-6510},
abstract = {BACKGROUND: Pseudomonas aeruginosa is a major cause of hospital-acquired infection due to its high antibiotic resistance and biofilm formation ability. P. aeruginosa produces elastase lasB during biofilm formation, which can influence properties of biofilm. This study was carried out to evaluate the antibiotic resistance and distribution of the lasB gene among biofilm-producing P. aeruginosa strains isolated from burn patients.<br><br>METHODS: A total of 128 clinical samples were collected from burn patients. The P. aeruginosa isolates were identified using standard bacteriological procedures. Antibiotic susceptibility test was performed by the disk diffusion method. Biofilm formation was measured by microtiter plate assay. The presence of lasB gene was detected by PCR.<br><br>RESULTS: A total of 75 samples were positive for P. aeruginosa. A high rate of resistance was seen against ceftriaxone, cefotaxime, and piperacillin/tazobactam. Biofilm formation was seen in 57.3% of the isolates and the prevalence of the lasB gene was 85.3%. Biofilm formation in isolates without lasB was lower and these isolates were more sensitive to imipenem and piperacillin/tazobactam.<br><br>CONCLUSIONS: In the present study, we did not find a statistically significant relationship among elastase gene (lasB) presence, antibiotic resistance, and biofilm formation in P. aeruginosa strains isolated from burn patients.},
}
@article {pmid30273348,
year = {2018},
author = {Pollini, S and Di Pilato, V and Landini, G and Di Maggio, T and Cannatelli, A and Sottotetti, S and Cariani, L and Aliberti, S and Blasi, F and Sergio, F and Rossolini, GM and Pallecchi, L},
title = {In vitro activity of N-acetylcysteine against Stenotrophomonas maltophilia and Burkholderia cepacia complex grown in planktonic phase and biofilm.},
journal = {PloS one},
volume = {13},
number = {10},
pages = {e0203941},
doi = {10.1371/journal.pone.0203941},
pmid = {30273348},
issn = {1932-6203},
abstract = {Stenotrophomonas maltophilia and Burkholderia cepacia complex (Bcc) have been increasingly recognized as relevant pathogens in hospitalized, immunocompromised and cystic fibrosis (CF) patients. As a result of complex mechanisms, including biofilm formation and multidrug resistance phenotype, S. maltophilia and Bcc respiratory infections are often refractory to therapy, and have been associated with a worse outcome in CF patients. Here we demonstrate for the first time that N-acetylcysteine (NAC), a mucolytic agent with antioxidant and anti-inflammatory properties, may exhibit antimicrobial and antibiofilm activity against these pathogens. The antimicrobial and antibiofilm activity of high NAC concentrations, potentially achievable by topical administration, was tested against a collection of S. maltophilia (n = 19) and Bcc (n = 19) strains, including strains from CF patients with acquired resistance traits. Minimum Inhibitory Concentrations (MICs) and Minimum Bactericidal Concentrations (MBCs) ranged from 16 to 32 mg/ml and from 32 to >32 mg/ml, respectively. Sub-MIC concentrations (i.e., 0.25 × MIC) slowed down the growth kinetics of most strains. In time-kill assays, 2-day-old biofilms were more affected than planktonic cultures, suggesting a specific antibiofilm activity of NAC against these pathogens. Indeed, a dose- and time-dependent antibiofilm activity of NAC against most of the S. maltophilia and Bcc strains tested was observed, with a sizable antibiofilm activity observed also at 0.5 and 1 × MIC NAC concentrations. Furthermore, at those concentrations, NAC was also shown to significantly inhibit biofilm formation with the great majority of tested strains.},
}
@article {pmid30270674,
year = {2018},
author = {Guarise, C and Barbera, C and Pavan, M and Pluda, S and Celestre, M and Galesso, D},
title = {Dopamine-functionalized sulphated hyaluronic acid as a titanium implant coating enhances biofilm prevention and promotes osseointegration.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-12},
doi = {10.1080/08927014.2018.1491555},
pmid = {30270674},
issn = {1029-2454},
abstract = {A series of new hyaluronan derivatives was synthesized and tested as an antibiotic release system by antibacterial and osseointegration assays. Specifically, partially sulphated hyaluronic acid (sHA) was functionalized with dopamine (DA). The DA moiety guarantees good performance as a binding agent for coating a titanium alloy surface; furthermore, the negatively charged sHA has bone regenerative effects and a high binding affinity for positively charged antibiotics. A sHA scaffold with a defined degree of sulphation (DS =2) was selected as a good compromise between a high negative charge density and poor heparin-like anticoagulant activity, while the degree of DA derivatization (17.1%mol) was chosen based on the absence of cytotoxic activity and the promotion of osteoblast proliferation. The titanium alloy coating was investigated indirectly using a fluorescent probe and directly by environmental scanning electron microscope (ESEM) analysis. Long-duration antibiotic release was demonstrated in vitro, and antibacterial efficacy against a Staphylococcus aureus culture was shown.},
}
@article {pmid30269283,
year = {2018},
author = {Dehghani, S and Rezaee, A and Hosseinkhani, S},
title = {Effect of alternating electrical current on denitrifying bacteria in a microbial electrochemical system: biofilm viability and ATP assessment.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-018-3170-0},
pmid = {30269283},
issn = {1614-7499},
abstract = {The present study considers the impact of the alternating electric current on the viability and biological activity of denitrifying bacteria in a microbial electrochemical system (MES). The bio-stimulation using low-frequency low-voltage alternating current (AC) was studied in terms of the adenosine triphosphate (ATP) level of bacteria, viability, morphological characteristics, cell size, and complexity. Apoptosis assays by flow cytometry revealed that 81-95% of the cells were non-apoptotic, and cell membrane damage occurred < 18%. The applied AC could affect the bacterial metabolic activity and ATP content in the denitrifying bacteria depending on characteristics of the alternating electric current. Scanning electron microscopy (SEM) analysis of cell morphology illustrated low cell deformations under AC stimulation. The obtained results revealed that the applied alternating electrical current could increase the metabolic activity of denitrifying bacteria, leading to a better denitrification. Graphical abstract ᅟ.},
}
@article {pmid30268774,
year = {2018},
author = {Kuehnast, T and Cakar, F and Weinhäupl, T and Pilz, A and Selak, S and Schmidt, MA and Rüter, C and Schild, S},
title = {Comparative analyses of biofilm formation among different Cutibacterium acnes isolates.},
journal = {International journal of medical microbiology : IJMM},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijmm.2018.09.005},
pmid = {30268774},
issn = {1618-0607},
abstract = {The Gram-positive anaerobic bacterium Cutibacterium acnes is a commensal of the human skin, but also an opportunistic pathogen that contributes to the pathophysiology of the skin disease acne vulgaris. Moreover, C. acnes, in addition to other skin-colonizing bacteria such as S. epidermidis and S. aureus, is an emerging pathogen of implant-associated infections. Notably, C. acnes isolates exhibit marked heterogeneity and can be divided into at least 6 phylotypes by multilocus sequence typing. It is becoming increasingly evident that biofilm formation is a relevant factor for C. acnes virulence, but information on biofilm formation by diverse C. acnes isolates is limited. In this study we performed a first comparative analysis of 58 diverse skin- or implant-isolates covering all six C. acnes phylotypes to investigate biofilm formation dynamics, biofilm morphology and attachment properties to abiotic surfaces. The results presented herein suggest that biofilm formation correlates with the phylotype, rather than the anatomical isolation site. IA1 isolates, particularly SLST sub-types A1 and A2, showed highest biofilm amounts in the microtiter plate assays, followed by isolates of the IC, IA2 and II phylotypes. Microscopic evaluation revealed well-structured three-dimensional biofilms and relatively high adhesive properties to abiotic surfaces for phylotypes IA1, IA2 and IC. Representatives of phylotype III formed biofilms with comparable biomass, but with less defined structures, whereas IB as well as II isolates showed the least complex three-dimensional morphology. Proteinase K- and DNase I-treatment reduced attachment rates of all phylotypes, therefore, indicating that extracellular DNA and proteins are critical for adhesion to abiotic surfaces. Moreover, proteins seem to be pivotal structural biofilm components as mature biofilms of all phylotypes were proteinase K-sensitive, whereas the sensitivity to DNase I-treatment varied depending on the phylotype.},
}
@article {pmid30267885,
year = {2018},
author = {Lee, SW and Gu, H and Kilberg, JB and Ren, D},
title = {Sensitizing bacterial cells to antibiotics by shape recovery triggered biofilm dispersion.},
journal = {Acta biomaterialia},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.actbio.2018.09.042},
pmid = {30267885},
issn = {1878-7568},
abstract = {Microbial biofilms are a leading cause of chronic infections in humans and persistent biofouling in industries due to extremely high-level tolerance of biofilm cells to antimicrobial agents. Eradicating mature biofilms is especially challenging because of the protection of the extracellular matrix and slow growth of biofilm cells. Recently, we reported that established biofilms can be effectively removed (e.g. 99.9% dispersion of 48 h Pseudomonas aeruginosa PAO1 biofilms) by shape memory polymer-based dynamic changes in surface topography. Here, we demonstrate that such biofilm dispersion also sensitizes biofilm cells to conventional antibiotics. For example, shape recovery in the presence of 50 µg/mL tobramycin reduced biofilm cell counts by more than 3 logs (2,479-fold) compared to the static flat control. The observed effects were attributed to the disruption of biofilm structure and increase in cellular activities as evidenced by an 11.8-fold increase in intracellular level of adenosine triphosphate (ATP), and 4.1-fold increase in expression of the rrnB gene in detached cells. These results can help guide the design of new control methods to better combat biofilm associated antibiotic-resistant infections.<br><br>STATEMENT OF SIGNIFICANCE: Microbial infections are challenging due to high-level antibiotic resistance of biofilm cells. The protection of an extracellular matrix and slow growth of biofilm cells render conventional antibiotics ineffective. Thus, it is important to develop new technologies that can remove mature biofilms and sensitize biofilm cells to antibiotics. Recently, we demonstrated that dynamic change in surface topography can remove 48 h Pseudomonas aeruginosa PAO1 biofilms by 99.9%. In this study, we investigated how shape recovery triggered dispersion affect the physiology of biofilm cells and associated antibiotic susceptibility. These results are helpful for understanding biofilm dispersion and developing more effective control methods.},
}
@article {pmid30263642,
year = {2017},
author = {Kwon, M and Hussain, MS and Oh, DH},
title = {Biofilm formation of Bacillus cereus under food-processing-related conditions.},
journal = {Food science and biotechnology},
volume = {26},
number = {4},
pages = {1103-1111},
doi = {10.1007/s10068-017-0129-8},
pmid = {30263642},
issn = {2092-6456},
abstract = {This study aims to understand the biofilm formation abilities of eight Bacillus cereus strains under food-industry-related conditions. Biofilms were grown in microtiter plates in tryptic soy broth (TSB) or brain heart infusion (BHI) at 30 °C for 24 or 48 h and quantified via the crystal violet assay. A significantly larger of biofilm was formed in TSB than in BHI after 48 h. Selected strains were used to test biofilm formation under food-related conditions produced by different surfaces (e.g., stainless steel, plastic, or glass), temperatures (25 or 30 °C), carbon sources, (glucose or glycerol) and NaCl. Biofilm formation appeared to be affected by surface properties, temperature, and carbon sources. A larger biofilm was formed on stainless steel at 30 °C compared to plastic and glass surfaces at 25 and 30 °C. Moreover, addition of glucose in combination with NaCl in TSB produced significantly larger biofilm than glucose, glycerol and/or NaCl. These results indicate that food-industry-related conditions could promote B. cereus biofilm formation, which is relevant to food safety.},
}
@article {pmid30263318,
year = {2016},
author = {Kim, BR and Bae, YM and Hwang, JH and Lee, SY},
title = {Biofilm formation and cell surface properties of Staphylococcus aureus isolates from various sources.},
journal = {Food science and biotechnology},
volume = {25},
number = {2},
pages = {643-648},
doi = {10.1007/s10068-016-0090-y},
pmid = {30263318},
issn = {2092-6456},
abstract = {This study investigated biofilm formation, cell surface hydrophobicity, colony spreading, and slime production for 112 Staphylococcus aureus strains isolated from various sources (leaf vegetables, pea leaf, perilla leaf, Kim-bab, person, and animal). When biofilm formation was classified by origin, S. aureus isolated from animal origin showed a significantly higher level of biofilm formation than others (p≤0.05). When S. aureus groups with different levels of biofilm formation (very strong, strong, moderate, and weak) were evaluated for the correlation with cell surface properties, there was a positive correlation between biofilm formation and hydrophobicity (r=0.926). Biofilm formation and colony spreading on tryptic soy broth (without dextrose) also showed positive correlation (r=0.863). In contrast, biofilm formation and slime production were negatively correlated (r=-0.973). Based on these results, the biofilm forming ability of S. aureus differs depending on their origin and might be affected by cell surface properties such as cell surface hydrophobicity.},
}
@article {pmid30265315,
year = {2018},
author = {Smith, HJ and Zelaya, AJ and De León, KB and Chakraborty, R and Elias, DA and Hazen, TC and Arkin, AP and Cunningham, AB and Fields, MW},
title = {Impact of hydrologic boundaries on microbial planktonic and biofilm communities in shallow terrestrial subsurface environments.},
journal = {FEMS microbiology ecology},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsec/fiy191},
pmid = {30265315},
issn = {1574-6941},
abstract = {Subsurface environments contain a large proportion of planetary microbial biomass and harbor diverse communities responsible for mediating biogeochemical cycles important to groundwater used by human society for consumption, irrigation, agriculture, and industry. Within the saturated zone, capillary fringe, and vadose zones, microorganisms can reside in two distinct phases (planktonic or biofilm), and significant differences in community composition, structure, and activity between free-living and attached communities are commonly accepted. However, largely due to sampling constraints and the challenges of working with solid substrata, the contribution of each phase to subsurface processes is largely unresolved. Here, we synthesize current information on the diversity and activity of shallow freshwater subsurface habitats, discuss the challenges associated with sampling planktonic and biofilm communities across spatial, temporal, and geological gradients, and discuss how biofilms may be constrained within shallow terrestrial subsurface aquifers. We suggest that merging traditional activity measurements and sequencing/-omics technologies with hydrological parameters important to sediment biofilm assembly and stability will help delineate key system parameters. Ultimately, integration will enhance our understanding of shallow subsurface ecophysiology in terms of bulk-flow through porous media and distinguish the respective activities of sessile microbial communities from more transient planktonic communities to ecosystem service and maintenance.},
}
@article {pmid30265307,
year = {2018},
author = {Dennis, EA and Coats, MT and Griffin, S and Pang, B and Briles, DE and Crain, MJ and Swords, WE},
title = {Hyperencapsulated Mucoid Pneumococcal Isolates from Patients with Cystic Fibrosis Have Increased Biofilm Density and Persistence In vivo.},
journal = {Pathogens and disease},
volume = {},
number = {},
pages = {},
doi = {10.1093/femspd/fty073},
pmid = {30265307},
issn = {2049-632X},
abstract = {Mucoid bacteria, predominately Pseudomonas aeruginosa, are commonly associated with decline in pulmonary function in children with cystic fibrosis (CF), and are thought to persist at least in part due to a greater propensity toward forming biofilms. We isolated a higher frequency of mucoid Streptococcus pneumoniae (Sp) expressing high levels of capsular polysaccharides from sputa from children with CF, compared to those without CF. We compared biofilm formation and maturation by mucoid and non-mucoid isolates of Sp collected from children with and without CF. Non-mucoid Sp serotype 19A and 19F isolates had significantly higher levels of biofilm initiation and adherence to CF epithelial cells than did serotype 3 isolates. However, strains expressing high levels of capsule had significantly greater biofilm maturation, as evidenced by increased density and thickness in static and continuous flow assays via confocal microscopy. Finally, using a serotype 3 Sp strain, we showed that highly encapsulated mucoid phase variants predominate during late adherence and better colonize CFTR-/- as compared to wild-type mice in respiratory infection studies. These findings indicate that overexpression of capsule can enhance the development of mature pneumococcal biofilms in vitro, and may contribute to pneumococcal colonization in CF lung disease.Word count: 196 words.},
}
@article {pmid30263875,
year = {2018},
author = {Salisbury, AM and Mayer, D and Chen, R and Percival, SL},
title = {Efficacy of Concentrated Surfactant-Based Wound Dressings in Wound Repair and Biofilm Reduction.},
journal = {Advances in wound care},
volume = {7},
number = {9},
pages = {315-322},
doi = {10.1089/wound.2017.0782},
pmid = {30263875},
issn = {2162-1918},
abstract = {Objective: This study was set up to evaluate the efficacy of a concentrated surfactant-based wound dressing (with and without silver sulfadiazine [SSD]) on wound repair, by investigating their ability to enhance human dermal fibroblast proliferation and viability. In addition, the wound dressings were evaluated for their ability to suppress biofilms in a three-dimensional (3D) in vitro wound biofilm model and modulate the inflammatory cytokine interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNFα). Approach: Problematic biofilms are well known to affect fibroblast and keratinocyte viability. To assess wound repair and inflammatory cytokine modulation, a direct cytotoxicity assay and a 3D keratinocyte-fibroblast model were employed. Results: At 1 and 7 days posttreatment, the non-antimicrobial dressing was noncytotoxic and the antimicrobial dressing was moderately cytotoxic to adult human dermal fibroblasts cells. Within the 3D wound model, the biofilm demonstrated a decelerating effect on wound closure and a decrease in viable cells. When the non-antimicrobial- and antimicrobial-based concentrated surfactant-based wound dressing was applied to the wound model, reduced biofilm was observed. The application of wound dressings to the biofilm-infected wound also resulted in a reduction of IL-6 and TNFα. The concentrated surfactant-based wound dressing without an antimicrobial was shown to enhance cellular viability and migration. Innovation and Conclusion: We have demonstrated the ability of a surfactant-based wound dressing to minimize the deleterious effects of a wound biofilm, modulate the secretion of inflammatory cytokines, and enhance cellular proliferation in a biofilm-infected wound model. Furthermore, the non-antimicrobial-based concentrated surfactant dressings did not affect cellular viability and therefore represents a multifaceted approach to the treatment of wounds infected with biofilms.},
}
@article {pmid30261443,
year = {2018},
author = {Neves, BG and Stipp, RN and Bezerra, DDS and Guedes, SFF and Rodrigues, LKA and Neves, BG and Stipp, RN and Bezerra, DS and Guedes, SFF and Rodrigues, LKA},
title = {Quantitative analysis of biofilm bacteria according to different stages of early childhood caries.},
journal = {Archives of oral biology},
volume = {96},
number = {},
pages = {155-161},
doi = {10.1016/j.archoralbio.2018.09.007},
pmid = {30261443},
issn = {1879-1506},
abstract = {OBJECTIVE: Monitoring selected key species related to health or disease may facilitate caries risk assessment and discovery of novel ecological preventive and therapeutic approaches. This study aimed at quantifying Actinomyces naeslundii, Bifidobacterium spp., Lactobacillus acidophilus, Lactobacillus casei group, Streptococcus gordonii, Mitis group and Streptococcus mutans by quantitative polymerase chain reaction (qPCR) in dental biofilm from Brazilian children with different stages of early childhood caries (ECC).<br><br>DESIGN: Seventy-five preschool children were clinically evaluated by ICDAS criteria and divided into groups: caries-free (CF; n = 20), enamel caries lesions (ECL; n = 17) and dentine caries lesions (DCL; n = 38). Plaque samples from all children were collected for detection and quantification of the selected bacteria.<br><br>RESULTS: L. acidophilus and L. casei group were absent in almost all plaque samples. No differences in relative proportions of A. naeslundii, Mitis group and S. gordonii were observed in any stage of caries. However, S. mutans and Bifidobacterium spp. were present at higher concentrations in the biofilm of children with DCL (p < 0.001). Multivariate analysis showed that S. mutans and Bifidobacterium spp. were strongly associated with biofilm in children with DCL.<br><br>CONCLUSION: Differences were observed in the proportion of acidogenic and aciduric bacteria with dental caries progression. The data indicate that S. mutans and Bifidobacterium spp. in dental biofilm may be involved in some progression processes for ECC.},
}
@article {pmid30258571,
year = {2018},
author = {Tsang, STJ and Gwynne, PJ and Gallagher, MP and Simpson, AHRW},
title = {The biofilm eradication activity of acetic acid in the management of periprosthetic joint infection.},
journal = {Bone &amp; joint research},
volume = {7},
number = {8},
pages = {517-523},
doi = {10.1302/2046-3758.78.BJR-2018-0045.R1},
pmid = {30258571},
issn = {2046-3758},
abstract = {Objectives: Periprosthetic joint infection following joint arthroplasty surgery is one of the most feared complications. The key to successful revision surgery for periprosthetic joint infections, regardless of treatment strategy, is a thorough deep debridement. In an attempt to limit antimicrobial and disinfectant use, there has been increasing interest in the use of acetic acid as an adjunct to debridement in the management of periprosthetic joint infections. However, its effectiveness in the eradication of established biofilms following clinically relevant treatment times has not been established. Using an in vitro biofilm model, this study aimed to establish the minimum biofilm eradication concentration (MBEC) of acetic acid following a clinically relevant treatment time.<br><br>Materials and Methods: Using a methicillin-sensitive Staphylococcus aureus (MSSA) reference strain and the dissolvable bead assay, biofilms were challenged by 0% to 20% acetic acid (pH 4.7) for ten minutes, 20 minutes, 180 minutes, and 24 hours.<br><br>Results: The MBEC of acetic acid was found to be: 15%, 11%, 3.2%, and 0.8% following a ten-minute, 20-minute, 180-minute, and 24-hour treatment, respectively.<br><br>Conclusion: This study found that the MBEC of acetic acid following a 10- or 20-minute treatment time exceeded its safety threshold, making these concentrations unsuitable as a topical debridement adjunct. However, a clinically acceptable concentration (5%) was still found to eliminate 96.1% of biofilm-associated MSSA following a 20-minute treatment time.Cite this article: S. T. J. Tsang, P. J. Gwynne, M. P. Gallagher, A. H. R. W. Simpson. The biofilm eradication activity of acetic acid in the management of periprosthetic joint infection. Bone Joint Res 2018;7:517-523. DOI: 10.1302/2046-3758.78.BJR-2018-0045.R1.},
}
@article {pmid30258415,
year = {2018},
author = {Poquet, I and Saujet, L and Canette, A and Monot, M and Mihajlovic, J and Ghigo, JM and Soutourina, O and Briandet, R and Martin-Verstraete, I and Dupuy, B},
title = {Clostridium difficile Biofilm: Remodeling Metabolism and Cell Surface to Build a Sparse and Heterogeneously Aggregated Architecture.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {2084},
doi = {10.3389/fmicb.2018.02084},
pmid = {30258415},
issn = {1664-302X},
abstract = {Clostridium difficile is an opportunistic entero-pathogen causing post-antibiotic and nosocomial diarrhea upon microbiota dysbiosis. Although biofilms could contribute to colonization, little is known about their development and physiology. Strain 630Δerm is able to form, in continuous-flow micro-fermentors, macro-colonies and submersed biofilms loosely adhesive to glass. According to gene expression data, in biofilm/planktonic cells, central metabolism is active and fuels fatty acid biosynthesis rather than fermentations. Consistently, succinate is consumed and butyrate production is reduced. Toxin A expression, which is coordinated to metabolism, is down-regulated, while surface proteins, like adhesins and the primary Type IV pili subunits, are over-expressed. C-di-GMP level is probably tightly controlled through the expression of both diguanylate cyclase-encoding genes, like dccA, and phosphodiesterase-encoding genes. The coordinated expression of genes controlled by c-di-GMP and encoding the putative surface adhesin CD2831 and the major Type IV pilin PilA1, suggests that c-di-GMP could be high in biofilm cells. A Bacillus subtilis SinR-like regulator, CD2214, and/or CD2215, another regulator co-encoded in the same operon as CD2214, control many genes differentially expressed in biofilm, and in particular dccA, CD2831 and pilA1 in a positive way. After growth in micro-titer plates and disruption, the biofilm is composed of robust aggregated structures where cells are embedded into a polymorphic material. The intact biofilm observed in situ displays a sparse, heterogeneous and high 3D architecture made of rods and micro-aggregates. The biofilm is denser in a mutant of both CD2214 and CD2215 genes, but it is not affected by the inactivation of neither CD2831 nor pilA1 . dccA, when over-expressed, not only increases the biofilm but also triggers its architecture to become homogeneous and highly aggregated, in a way independent of CD2831 and barely dependent of pilA1 . Cell micro-aggregation is shown to play a major role in biofilm formation and architecture. This thorough analysis of gene expression reprogramming and architecture remodeling in biofilm lays the foundation for a deeper understanding of this lifestyle and could lead to novel strategies to limit C. difficile spread.},
}
@article {pmid30258041,
year = {2018},
author = {Lécuyer, F and Bourassa, JS and Gélinas, M and Charron-Lamoureux, V and Burrus, V and Beauregard, PB},
title = {Biofilm Formation Drives Transfer of the Conjugative Element ICEBs1 in Bacillus subtilis.},
journal = {mSphere},
volume = {3},
number = {5},
pages = {},
doi = {10.1128/mSphere.00473-18},
pmid = {30258041},
issn = {2379-5042},
abstract = {Horizontal gene transfer by integrative and conjugative elements (ICEs) is a very important mechanism for spreading antibiotic resistance in various bacterial species. In environmental and clinical settings, most bacteria form biofilms as a way to protect themselves against extracellular stress. However, much remains to be known about ICE transfer in biofilms. Using ICEBs1 from Bacillus subtilis, we show that the natural conjugation efficiency of this ICE is greatly affected by the ability of the donor and recipient to form a biofilm. ICEBs1 transfer considerably increases in biofilm, even at low donor/recipient ratios. Also, while there is a clear temporal correlation between biofilm formation and ICEBs1 transfer, biofilms do not alter the level of ICEBs1 excision in donor cells. Conjugative transfer appears to be favored by the biophysical context of biofilms. Indeed, extracellular matrix production, particularly from the recipient cells, is essential for biofilms to promote ICEBs1 transfer. Our study provides basic new knowledge on the high rate of conjugative transfer of ICEs in biofilms, a widely preponderant bacterial lifestyle in the environment, which could have a major impact on our understanding of horizontal gene transfer in natural and clinical environments.IMPORTANCE Transfer of mobile genetic elements from one bacterium to another is the principal cause of the spread of antibiotic resistance. However, the dissemination of these elements in environmental contexts is poorly understood. In clinical and environmental settings, bacteria are often found living in multicellular communities encased in a matrix, a structure known as a biofilm. In this study, we examined how forming a biofilm influences the transmission of an integrative and conjugative element (ICE). Using the model Gram-positive bacterium B. subtilis, we observed that biofilm formation highly favors ICE transfer. This increase in conjugative transfer is due to the production of extracellular matrix, which creates an ideal biophysical context. Our study provides important insights into the role of the biofilm structure in driving conjugative transfer, which is of major importance since biofilm is a widely preponderant bacterial lifestyle for clinically relevant bacterial strains.},
}
@article {pmid30254619,
year = {2018},
author = {De, A and Jorgensen, AN and Beatty, WL and Lemos, J and Wen, ZT},
title = {Deficiency of MecA in Streptococcus mutans Causes Major Defects in Cell Envelope Biogenesis, Cell Division, and Biofilm Formation.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {2130},
doi = {10.3389/fmicb.2018.02130},
pmid = {30254619},
issn = {1664-302X},
abstract = {MecA is an adaptor protein that guides the ClpC/P-mediated proteolysis. A S. mutans MecA-deficient mutant was constructed by double-crossover allelic exchange and analyzed for the effects of such a deficiency on cell biology and biofilm formation. Unlike the wild-type, UA159, the mecA mutant, TW416, formed mucoid and smooth colonies, severely clumped in broth and had a reduced growth rate. Transmission electron microscopy analysis revealed that TW416 grows primarily in chains of giant &quot;swollen&quot; cells with multiple asymmetric septa, unlike the coccoid form of UA159. As compared to UA159, biofilm formation by TW416 was significantly reduced regardless of the carbohydrate sources used for growth (P < 0.001). Western blot analysis of TW416 whole cell lysates showed a reduced expression of the glucosyltransferase GtfC and GtfB, as well as the P1 and WapA adhesins providing an explanation for the defective biofilm formation of TW416. When analyzed by a colorimetric assay, the cell wall phosphate of the mutant murein sacculi was almost 20-fold lower than the parent strain (P < 0.001). Interestingly, however, when analyzed using immunoblotting of the murein sacculi preps with UA159 whole cell antiserum as a probe, TW416 was shown to possess significantly higher signal intensity as compared to the wild-type. There is also evidence that MecA in S. mutans is more than an adaptor protein, although how it modulates the bacterial pathophysiology, including cell envelope biogenesis, cell division, and biofilm formation awaits further investigation.},
}
@article {pmid30254440,
year = {2018},
author = {Zhang, X and Geng, H and Gong, L and Zhang, Q and Li, H and Zhang, X and Wang, Y and Gao, P},
title = {Modification of the surface of titanium with multifunctional chimeric peptides to prevent biofilm formation via inhibition of initial colonizers.},
journal = {International journal of nanomedicine},
volume = {13},
number = {},
pages = {5361-5375},
doi = {10.2147/IJN.S170819},
pmid = {30254440},
issn = {1178-2013},
abstract = {Background: Prevention of bacterial colonization remains a major challenge in the field of oral implant devices. Chimeric peptides with binding, antimicrobial, and osteogenesis motifs may provide a promising alternative for the inhibition of biofilm formation on titanium (Ti) surfaces.<br><br>Methods: In this study, chimeric peptides were designed by connecting an antimicrobial sequence from human β-defensin-3 with a Ti-binding sequence and arginine-glycine-aspartic acid using a glycine-glycine-glycine linker. Binding to the Ti substrate and antimicrobial properties against streptococci were evaluated. Significant improvement in reduction of bacterial colonization onto the Ti surface was observed, with or without the presence of saliva or serum. The MC3T3-E1 cells grew well on the modified Ti surfaces compared with the control group.<br><br>Results: The data showed that the three peptide functional motifs maintained their respective functions, and that the antibiofilm mechanism of the chimeric peptide was via suppression of sspA and sspB gene expression.<br><br>Conclusion: These results indicated that the endogenous peptide fragments engineered on the Ti surface could provide an environmentally friendly approach for improving the biocompatibility of oral implants.},
}
@article {pmid30254118,
year = {2018},
author = {Reichhardt, C and Wong, C and Passos da Silva, D and Wozniak, DJ and Parsek, MR},
title = {CdrA Interactions within the Pseudomonas aeruginosa Biofilm Matrix Safeguard It from Proteolysis and Promote Cellular Packing.},
journal = {mBio},
volume = {9},
number = {5},
pages = {},
doi = {10.1128/mBio.01376-18},
pmid = {30254118},
issn = {2150-7511},
abstract = {Biofilms are robust multicellular aggregates of bacteria that are encased in an extracellular matrix. Different bacterial species have been shown to use a range of biopolymers to build their matrices. Pseudomonas aeruginosa is a model organism for the laboratory study of biofilms, and past work has suggested that exopolysaccharides are a required matrix component. However, we found that expression of the matrix protein CdrA, in the absence of biofilm exopolysaccharides, allowed biofilm formation through the production of a CdrA-rich proteinaceous matrix. This represents a novel function for CdrA. Similar observations have been made for other species such as Escherichia coli and Staphylococcus aureus, which can utilize protein-dominant biofilm matrices. However, we found that these CdrA-containing matrices were susceptible to both exogenous and self-produced proteases. We previously reported that CdrA directly binds the biofilm matrix exopolysaccharide Psl. Now we have found that when CdrA bound to Psl, it was protected from proteolysis. Together, these results support the idea of the importance of multibiomolecular components in matrix stability and led us to propose a model in which CdrA-CdrA interactions can enhance cell-cell packing in an aggregate that is resistant to physical shear, while Psl-CdrA interactions enhance aggregate integrity in the presence of self-produced and exogenous proteases.IMPORTANCEPseudomonas aeruginosa forms multicellular aggregates or biofilms using both exopolysaccharides and the CdrA matrix adhesin. We showed for the first time that P. aeruginosa can use CdrA to build biofilms that do not require known matrix exopolysaccharides. It is appreciated that biofilm growth is protective against environmental assaults. However, little is known about how the interactions between individual matrix components aid in this protection. We found that interactions between CdrA and the exopolysaccharide Psl fortify the matrix by preventing CdrA proteolysis. When both components-CdrA and Psl-are part of the matrix, robust aggregates form that are tightly packed and protease resistant. These findings provide insight into how biofilms persist in protease-rich host environments.},
}
@article {pmid30252827,
year = {2018},
author = {Danino, MA and Paek, LS and Elkhatib, A and Obeid, F and Boumerhi, J},
title = {Reply: Do Bacteria and Biofilm Play a Role in Double-Capsule Formation around Macrotextured Implants?.},
journal = {Plastic and reconstructive surgery},
volume = {142},
number = {4},
pages = {589e-590e},
doi = {10.1097/PRS.0000000000004745},
pmid = {30252827},
issn = {1529-4242},
}
@article {pmid30252650,
year = {2018},
author = {Cheng, X and Xu, W and Wang, N and Mu, Y and Zhu, J and Luo, J},
title = {Adsorption of Cu2+ and mechanism by natural biofilm.},
journal = {Water science and technology : a journal of the International Association on Water Pollution Research},
volume = {78},
number = {4},
pages = {721-731},
doi = {10.2166/wst.2018.308},
pmid = {30252650},
issn = {0273-1223},
abstract = {The biofilm culturing device fixed on the slides was vertically placed in the commonly called small Li Lake of Jiangnan University. The adsorption experiment of Cu2+ was carried out by mature biofilm. Besides, scanning electron microscope (SEM), polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-energy spectrum (SEM-EDX) were used to analysis the effect of Cu2+ on the morphological structure of biofilm. The result indicated that when the initial concentration of Cu2+ was 5 mg·L-1, the absorption capacity of Cu2+ by unit mass biofilm is the maximum. More extracellular polymeric substances (EPS) were released by biofilm due to the stimulation of Cu2+. EPS was beneficial to the adsorption of Cu2+ by biofilm. After the adsorption of Cu2+, the bacterial diversity index decreased, while there were no significant differences in microbial communities on biofilm. Moreover, the main groups combining Cu2+ were the hydroxyl groups and amide groups in S-EPS and B-EPS. Ion exchange is a mechanism of the adsorption of Cu2+ by EPS.},
}
@article {pmid30252590,
year = {2018},
author = {Ovesen, S and Durack, J and Kirk, KF and Nielsen, HL and Nielsen, H and Lynch, SV},
title = {Motility and biofilm formation of the emerging gastrointestinal pathogen Campylobacter concisus differs under microaerophilic and anaerobic environments.},
journal = {Gut microbes},
volume = {},
number = {},
pages = {1-27},
doi = {10.1080/19490976.2018.1472201},
pmid = {30252590},
issn = {1949-0984},
abstract = {Campylobacter concisus has been isolated from patients with gastroenteritis and inflammatory bowel disease (IBD), as well as healthy subjects. While strain differences may plausibly explain virulence differentials, an alternative hypothesis posits that the pathogenic potential of this species may depend on altered ecosystem conditions in the inflamed gut. One potential difference is oxygen availability, which is frequently increased under conditions of inflammation and is known to regulate bacterial virulence. Hence, we hypothesized that oxygen influences C. concisus physiology. We therefore characterized the effect of microaerophilic or anaerobic environments on C. concisus motility and biofilm formation, two important determinants of host colonization and dissemination. C. concisus isolates (n = 46) sourced from saliva, gut mucosal biopsies and feces of patients with IBD (n = 23), gastroenteritis (n = 8) and healthy subjects (n = 13), were used for this study. Capacity to form biofilms was determined using crystal violet assay, while assessment of dispersion through soft agar permitted motility to be assessed. No association existed between GI disease and either motility or biofilm forming capacity. Oral isolates exhibited significantly greater capacity for biofilm formation compared to fecal isolates (p<0.03), and showed a strong negative correlation between motility and biofilm formation (r = -0.7; p = 0.01). Motility significantly increased when strains were cultured under microaerophilic compared to anaerobic conditions (p<0.001). Increased biofilm formation under microaerophillic conditions was also observed for a subset of isolates. Hence, differences in oxygen availability appear to influence key physiological aspects of the opportunistic gastrointestinal pathogen C. concisus.},
}
@article {pmid30249749,
year = {2018},
author = {Pang, B and Armbruster, CE and Foster, G and Learman, BS and Gandhi, U and Swords, WE},
title = {Autoinducer 2 (AI-2) production by nontypeable Haemophilus influenzae 86-028NP promotes expression of a predicted glycosyltransferase that is a determinant of biofilm maturation, prevention of dispersal, and persistence in vivo.},
journal = {Infection and immunity},
volume = {},
number = {},
pages = {},
doi = {10.1128/IAI.00506-18},
pmid = {30249749},
issn = {1098-5522},
abstract = {Nontypeable Haemophilus influenzae (NTHi) is an extremely common human pathobiont that persists on the airway mucosal surface within biofilm communities, and our prior work has shown that NTHi biofilm maturation is coordinated by production and uptake of AI-2 quorum signals. To directly test roles for AI-2 in maturation and maintenance of NTHi biofilms, we generated an NTHi 86-028NP mutant in which luxS transcription was under control of the xylA promoter (NTHi 86-028NP luxS xylA::luxS), rendering AI-2 production inducible by xylose. Comparison of biofilms under inducing and noninducing conditions revealed a biofilm defect in the absence of xylose, whereas biofilm maturation increased following xylose induction. Removal of xylose resulted in interruption of luxS expression and biofilm dispersal. Measurement of luxS transcript by real-time RT-PCR showed that luxS expression peaked as biofilms matured, and waned before dispersal. Transcript profiling revealed significant changes following induction of luxS, including increased transcript for a predicted family 8 glycosyltransferase (NTHI1750, designated gstA); this result was confirmed by real-time RT-PCR. An isogenic NTHi 86-028NP gstA mutant had a biofilm defect, including decreased level of sialylated matrix and significantly altered biofilm structure. In experimental chinchilla infections we observed a significant decrease in bacteria in the biofilm population (but not in effusions) for NTHi 86-028NP gstA as compared to the parental strain. Therefore, we conclude that AI-2 promotes NTHi biofilm maturation and maintenance of biofilm integrity, due at least in part to expression of a probable glycosyltransferase that is potentially involved in synthesis of the biofilm matrix.},
}
@article {pmid30249747,
year = {2018},
author = {Heim, CE and West, SC and Ali, H and Kielian, T},
title = {Heterogeneity of Ly6G+Ly6C+ myeloid-derived suppressor cell (MDSC) infiltrates during S. aureus biofilm infection.},
journal = {Infection and immunity},
volume = {},
number = {},
pages = {},
doi = {10.1128/IAI.00684-18},
pmid = {30249747},
issn = {1098-5522},
abstract = {Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature monocytes and granulocytes. While neutrophils (PMNs) are classically identified as highly differentiated cells specialized for anti-microbial defense, our laboratory has reported minor contributions of PMNs to the immune response during S. aureus biofilm infection. However, these two cell types can be difficult to differentiate because of shared surface marker expression. Here we describe a more refined approach to distinguish MDSCs from PMNs utilizing the integrin receptor CD11b combined with conventional Ly6G and Ly6C expression. This approach separated the Ly6G+Ly6C+ population that we previously identified in a mouse model of S. aureus orthopedic implant infection into two subsets, namely Ly6G+Ly6C+CD11bhigh MDSCs and Ly6GlowLy6ClowCD11blow PMNs, which was confirmed by characteristic nuclear morphology using cytospins. Ly6G+Ly6C+CD11bhigh MDSCs suppressed T cell proliferation throughout the 28 day infection period, whereas Ly6G+Ly6C+CD11blow PMNs had no effect early (day 3 post-infection), although this population acquired suppressive activity at later stages of biofilm development. To further highlight the distinctions between biofilm-associated MDSCs and PMNs versus monocytes, transcriptional profiles were compared by RNA-Seq. A total of 6,466 genes were significantly differentially expressed in MDSCs vs. monocytes, whereas only 297 genes were significantly different between MDSCs and PMNs. A number of genes implicated in cell cycle regulation were identified, and in vivo EdU labeling revealed that approximately 50% of MDSCs proliferated locally at the site of S. aureus biofilm infection. Based on their similar transcriptomic profiles to PMNs, biofilm-associated MDSCs are of granulocytic lineage and can be classified as G-MDSCs.},
}
@article {pmid30249706,
year = {2018},
author = {Afonina, I and Lim, XN and Tan, R and Kline, KA},
title = {Planktonic interference and biofilm alliance between aggregation substance and endocarditis and biofilm associated pili in Enterococcus faecalis.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00361-18},
pmid = {30249706},
issn = {1098-5530},
abstract = {Like many bacteria, Enterococcus faecalis encodes a number of adhesins involved in colonization or infection of different niches. Two well-studied E. faecalis adhesins, aggregation substance (AS) and endocarditis and biofilm-associated pili (Ebp), both contribute to biofilm formation on abiotic surfaces and in endocarditis, suggesting they may be expressed at the same time. Because different regulatory pathways have been reported for AS and Ebp, here we examined if they are co-expressed on the same cells and the functional impact of co-expression on individual cells and within a population. We found that while Ebp are only expressed on a subset of cells, when Ebp and AS are expressed on the same cells, pili interfere with AS-mediated clumping and impede AS-mediated conjugative plasmid transfer during planktonic growth. However, when the population density increases, horizontal gene transfer rates normalize and are no longer affected by pilus expression. Instead, at higher cell densities during biofilm formation, Ebp and AS differentially contribute to biofilm development and structure, synergizing to promote maximal biofilm formation.IMPORTANCE Most bacteria express multiple adhesins that contribute to surface attachment and colonization. However, the network and relationships between the various adhesins of a single bacterial species are less-well understood. Here we examined two well-characterized adhesins in Enterococcus faecalis, aggregation substance and endocarditis and biofilm-associated pili, and found that they exhibit distinct functional contributions depending on the growth stage of the bacterial community. Pili interfere with aggregation substance-mediated clumping and plasmid transfer in planktonic conditions, whereas both adhesins structurally complement one another during biofilm development. This study advances our understanding of how E. faecalis, a ubiquitous member of the human gut microbiome and an opportunistic pathogen, uses multiple surface structures to evolve and thrive.},
}
@article {pmid30248650,
year = {2018},
author = {Li, J and Ye, W and Wei, D and Ngo, HH and Guo, W and Qiao, Y and Xu, W and Du, B and Wei, Q},
title = {System performance and microbial community succession in a partial nitrification biofilm reactor in response to salinity stress.},
journal = {Bioresource technology},
volume = {270},
number = {},
pages = {512-518},
doi = {10.1016/j.biortech.2018.09.068},
pmid = {30248650},
issn = {1873-2976},
abstract = {The system performance and microbial community succession in a partial nitrification biofilm reactor in response to salinity stress was conducted. It was found that the NH4+-N removal efficiency decreased from 98.4% to 42.0% after salinity stress increased to 20 g/L. Specific oxygen uptake rates suggested that AOB activity was more sensitive to the stress of salinity than that of NOB. Protein and polysaccharides contents showed an increasing tendency in both LB-EPS and TB-EPS after the salinity exposure. Moreover, EEM results indicated that protein-like substances were the main component in LB-EPS and TB-EPS as self-protection in response to salinity stress. Additionally, humic acid-like substances were identified as the main component in the effluent organic matter (EfOM) of partial nitrification biofilm, whereas fulvic acid-like substances were detected at 20 g/L salinity stress. Microbial community analysis found that Nitrosomonas as representative species of AOB were significantly inhibited under high salinity condition.},
}
@article {pmid30247876,
year = {2018},
author = {Hagras, M and Abutaleb, NS and Ali, A and Abdel-Aleem, J and Elsebaei, M and Seleem, MN and Mayhoub, AS},
title = {Naphthylthiazoles: targeting multidrug-resistant and intracellular Staphylococcus aureus with biofilm disruption activity.},
journal = {ACS infectious diseases},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsinfecdis.8b00172},
pmid = {30247876},
issn = {2373-8227},
abstract = {Thirty-two new naphthylthiazole derivatives were synthesized with the aim of exploring their antimicrobial effect on multidrug-resistant Gram-positive bacteria. Compounds 25 and 32, with ethylenediamine and methylguanidine side chains, represent the most promising derivatives, as their antibacterial spectrum includes activity against multidrug-resistant staphylococcal and enterococcal strains. Moreover, the new derivatives are highly advantageous over the existing frontline therapeutics for the treatment of multidrug-resistant Gram-positive bacteria. In this vein, compound 25 possesses three attributes: no bacterial resistance was developed against it even after 15 passages, it was very efficient in targeting intracellular pathogens, and it exhibited a concentration-dependent ability to disrupt the preformed bacterial biofilm.},
}
@article {pmid30246765,
year = {2018},
author = {Pournajaf, A and Razavi, S and Irajian, G and Ardebili, A and Erfani, Y and Solgi, S and Yaghoubi, S and Rasaeian, A and Yahyapour, Y and Kafshgari, R and Shoja, S and Rajabnia, R},
title = {Integron types, antimicrobial resistance genes, virulence gene profile, alginate production and biofilm formation in Iranian cystic fibrosis Pseudomonas aeruginosa isolates.},
journal = {Le infezioni in medicina : rivista periodica di eziologia, epidemiologia, diagnostica, clinica e terapia delle patologie infettive},
volume = {26},
number = {3},
pages = {226-236},
pmid = {30246765},
issn = {1124-9390},
abstract = {Cystic fibrosis (CF) patients commonly suffer from continuous and recurrent lung infections caused by Pseudomonas aeruginosa, the dominant pathogen in CF airways. This study aimed to determine the integron types, gene cassettes, virulence determinants, β-lactam resistance genes, biofilm formation and alginate production in P. aeruginosa isolated from Iranian CF patients. A total of 143 P. aeruginosa isolates were obtained from CF patients. Susceptibility of isolates to different antimicrobials was evaluated by disc diffusion method. ESBL, MBL and KPC production was assessed. Congo red agar and tissue culture plates were used for evaluation of biofilm formation. Alginate production was determined using the Carbazole assay. Integrase genes, resistance determinants (ESBLs, MBLs and KPC) and genes encoding virulence factors were evaluated by PCR. All isolates were susceptible to colistin, piperacillin-tazobactam and ticarcillin; 8.4% of isolates were considered as MDR phenotype. Out of 6.3% IPM-resistant isolates, prevalence of virulence genes was as follows: lasB (100%) and plcB (100%), plcH (96.5%). Biofilm formation and alginate production ability were found in 54.5% of isolates. The prevalence of the alginate-encoding genes was 92.3%, 86.7% and 67.1% for algD, algU and algL genes, respectively. PpyR, pslA and pelA genes were detected in 98.6%, 89.5% and 57.3% of the isolates, respectively. The high prevalence of colonization in CF lungs may increase the pathogenicity of P. aeruginosa due to their adhesion and protective properties caused by biofilm- and alginate-production. LasB, plcB, plcH, exoS, toxA, algD, ppyR and pslA genes were predominant in CF P. aeruginosa strains.},
}
@article {pmid30245590,
year = {2018},
author = {Yang, Y and Shao, Z and Du, J and He, Q and Chai, H},
title = {Enhancement of Organic Matter Removal in an Integrated Biofilm-Membrane Bioreactor Treating High-Salinity Wastewater.},
journal = {Archaea (Vancouver, B.C.)},
volume = {2018},
number = {},
pages = {2148286},
doi = {10.1155/2018/2148286},
pmid = {30245590},
issn = {1472-3654},
abstract = {High salinity can strongly inhibit microbial activity and decrease the sedimentation ability of activated sludge. The combination of biofilm and membrane bioreactor is a practical approach towards effective removal of pollutants and low fouling rate. An integrated biofilm-membrane bioreactor (BMBR) treating mustard tuber wastewater was investigated. An average COD removal efficiency of 94.81% and ammonium removal efficiency of 96.84% were achieved at an organic load of 0.5 kg COD/(m3·d). However, the reactor showed a relatively low efficiency in total nitrogen and soluble phosphorus removal due to the lack of anaerobic environment. The increase of influent organic load resulted in a performance degradation because a balance between the degradation ability and pollution has been reached. Images of scanning electron microscopy revealed that halophilic bacteria were the dominant microbe in the system that leads to a loose sludge structure and declined settling properties. It was found that membrane fouling was the consequence of the interaction of microbial activities and NaCl crystallization.},
}
@article {pmid30245456,
year = {2018},
author = {Cai, P and Liu, X and Ji, D and Yang, S and Walker, SL and Wu, Y and Gao, C and Huang, Q},
title = {Impact of soil clay minerals on growth, biofilm formation, and virulence gene expression of Escherichia coli O157:H7.},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {243},
number = {Pt B},
pages = {953-960},
doi = {10.1016/j.envpol.2018.09.032},
pmid = {30245456},
issn = {1873-6424},
abstract = {Soil, composed mainly of minerals, plays a central role in the circulation of microbial pathogens in the environment. Herein, the growth, biofilm formation, and virulence gene expression of the pathogenic bacteria Escherichia coli O157:H7 were monitored following exposure to montmorillonite, kaolinite, and goethite, three common soil minerals in the clay size fraction. E. coli O157:H7 growth was notably promoted (P < 0.05), while biofilm formation was inhibited in the presence of montmorillonite (P < 0.05), which is attributed to the suppression of colanic acid (CA) production and an increase in bacterial motility. Kaolinite not only promoted bacterial growth (P < 0.05), but also contributed to biofilm formation upon stimulating CA production. Upon exposure to goethite, notably slower bacterial growth and higher biomass of biofilm were observed as compared to the control (P < 0.05). Goethite stimulated the synthesis of CA to encase cells in a protective biofilm in response to the tight association between bacteria and goethite, which could cause bacterial death. Additionally, the transcription of virulence factors (stxA-1 and stxA-2) was significantly decreased in goethite or kaolinite system (P < 0.05). These findings indicate that minerals play important roles in the physiological state of bacteria and ultimately govern the fate of this pathogen in soils.},
}
@article {pmid30245399,
year = {2018},
author = {Li, YB and Liu, J and Huang, ZX and Yu, JH and Xu, XF and Sun, PH and Lin, J and Chen, WM},
title = {Design, synthesis and biological evaluation of 2-substituted 3-hydroxy-6-methyl-4H-pyran-4-one derivatives as Pseudomonas aeruginosa biofilm inhibitors.},
journal = {European journal of medicinal chemistry},
volume = {158},
number = {},
pages = {753-766},
doi = {10.1016/j.ejmech.2018.09.041},
pmid = {30245399},
issn = {1768-3254},
abstract = {Drug-resistant bacteria associated with biofilm formation are rapidly on the rise, requiring novel therapeutic options to combat biofilm induced drug-resistance. In this study, a class of 3-hydroxy-2-(phenylhydroxy-methyl)-6-methyl-4H-pyran-4-one derivatives (1a-1e) were found by screening of an in-house compound library to be potential Pseudomonas aeruginosa biofilm inhibitors. Thirty one novel 2-substituted 3-hydroxy-6-methyl-4H-pyran-4-one derivatives were synthesized and assayed for their biofilm inhibitory activity. A promising biofilm inhibitor 6a was identified, and showed an obvious biofilm inhibitory effect even at a concentration of 2.5 μM. Further mechanism studies revealed that 6a only shows inhibitory effects on the expression of pqsA-gfp in a fluorescent reporter strain, and the production of a PQS- regulated virulence factor, pyocyanin. This indicates that this type of compound exercises its anti-biofilm activity specifically through the PQS pathway. Novel chemical biofilm inhibitors are described here and guard against biofilm formation associated with Pseudomonas aeruginosa infections.},
}
@article {pmid30245289,
year = {2018},
author = {Barilli, E and Vismarra, A and Villa, Z and Bonilauri, P and Bacci, C},
title = {ESβL E. coli isolated in pig's chain: Genetic analysis associated to the phenotype and biofilm synthesis evaluation.},
journal = {International journal of food microbiology},
volume = {289},
number = {},
pages = {162-167},
doi = {10.1016/j.ijfoodmicro.2018.09.012},
pmid = {30245289},
issn = {1879-3460},
abstract = {Resistance to new generation cephalosporins is an important public health problem globally, in terms of economic and social costs, morbidity and mortality. Βeta-lactamase enzymes are mainly responsible for the antibiotic resistance of Gram negative bacteria and extended-spectrum-β-lactamases (ESβLs) are one of the major determinants of resistance against oxymino-cephalosporins in Enterobacteriaceae. Food-producing animals represent one of the sources of antibiotic resistant bacteria, including pigs. Here we analysed the presence of E. coli resistant to III generation cephalosporins isolated from different matrices collected from intensively bred pigs. A total of 498 E. coli were isolated from faeces and carcasses of pigs at slaughterhouse as well as from pork meat and sausages. Among these, 73 were phenotypically confirmed to be ESβL producers. Genetic analysis revealed that all except two harboured at least one of the three selected genes: blaCTX-M, blaTEM, and blaSHV. Furthermore, six of the E. coli ESβL isolated from faeces and carcasses swabs, were also able to produce biofilm, highlighting the virulence potential of these strains. The presence of Multi-Drug-Resistance patterns (MDR) recorded by the 73 ESβL E. coli was significant (60% of the strains were resistant to more than six antibiotics in MIC test). Results from the present study show that the transmission of resistant bacteria is possible along the food chain, including production of pork, one the most highly consumed meats around the world. Transmission is possible through the ingestion of raw meat products, and following cross-contamination between raw and cooked foods during preparation. The potential risk for human health demonstrated here, associated with the consumption of pork contaminated with bacterial strains characterized by multidrug resistance patterns, and the ability to produce ESβL and biofilm, is cause for concern. It is imperative to study future control strategies to avoid or limit as much as possible the transmission of these highly pathogenic strains through food consumption and/or contact with the environment.},
}
@article {pmid30242260,
year = {2018},
author = {Anderson, AC and Rothballer, M and Altenburger, MJ and Woelber, JP and Karygianni, L and Lagkouvardos, I and Hellwig, E and Al-Ahmad, A},
title = {In-vivo shift of the microbiota in oral biofilm in response to frequent sucrose consumption.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {14202},
doi = {10.1038/s41598-018-32544-6},
pmid = {30242260},
issn = {2045-2322},
support = {AL-1179/2-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; AL-1179/2-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; },
abstract = {Caries is associated with shifts of microbiota in dental biofilms and primarily driven by frequent sucrose consumption. Data on environmentally induced in vivo microbiota shifts are scarce therefore we investigated the influence of frequent sucrose consumption on the oral biofilm. Splint systems containing enamel slabs were worn for 3 × 7 days with 7-day intervals to obtain oral biofilm samples. After a three-month dietary change of sucking 10 g of sucrose per day in addition to the regular diet, biofilm was obtained again at the end of the second phase. The microbiota was analysed using Illumina MiSeq amplicon sequencing (v1-v2 region). In addition, roughness of the enamel surface was measured with laser scanning microscopy. The sucrose phase resulted in significant differences in beta-diversity and significantly decreased species richness. It was marked by a significant increase in abundance of streptococci, specifically Streptococcus gordonii, Streptococcus parasanguinis and Streptococcus sanguinis. Enamel surface roughness began to increase, reflecting initial impairment of dental enamel surface. The results showed that frequent sucrose consumption provoked compositional changes in the microbiota, leading to an increase of non-mutans streptococci, hence supporting the extended ecological plaque hypothesis and emphasizing the synergy of multiple bacterial species in the development of caries.},
}
@article {pmid30241381,
year = {2018},
author = {Souza, LBFC and Silva-Rocha, WP and Ferreira, MRA and Soares, LAL and Svidzinski, TIE and Milan, EP and Pires, RH and Fusco Almeida, AM and Mendes-Giannini, MJS and Maranhão Chaves, G},
title = {Influence of Eugenia uniflora Extract on Adhesion to Human Buccal Epithelial Cells, Biofilm Formation, and Cell Surface Hydrophobicity of Candida spp. from the Oral Cavity of Kidney Transplant Recipients.},
journal = {Molecules (Basel, Switzerland)},
volume = {23},
number = {10},
pages = {},
doi = {10.3390/molecules23102418},
pmid = {30241381},
issn = {1420-3049},
support = {PROCAD-NF-2008//CAPES/ ; },
abstract = {This study evaluated the influence of the extract of Eugenia uniflora in adhesion to human buccal epithelial cells (HBEC) biofilm formation and cell surface hydrophobicity (CSH) of Candida spp. isolated from the oral cavity of kidney transplant patients. To evaluate virulence attributes in vitro, nine yeasts were grown in the presence and absence of 1000 μg/mL of the extract. Adhesion was quantified using the number of Candida cells adhered to 150 HBEC determined by optical microscope. Biofilm formation was evaluated using two methodologies: XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and crystal violet assay, and further analyzed by electronic scan microscopy. CSH was quantified with the microbial adhesion to hydrocarbons test. We could detect that the extract of E. uniflora was able to reduce adhesion to HBEC and CSH for both Candida albicans and non-Candida albicansCandida species. We also observed a statistically significant reduced ability to form biofilms in biofilm-producing strains using both methods of quantification. However, two highly biofilm-producing strains of Candida tropicalis had a very large reduction in biofilm formation. This study reinforces the idea that besides growth inhibition, E. uniflora may interfere with the expression of some virulence factors of Candida spp. and may be possibly applied in the future as a novel antifungal agent.},
}
@article {pmid30240195,
year = {2018},
author = {Wang, X and Wu, J and Li, P and Wang, L and Zhou, J and Zhang, G and Li, X and Hu, B and Xing, X},
title = {Microenvironment-Responsive Magnetic Nanocomposites Based on Silver Nanoparticles/Gentamicin for Enhanced Biofilm Disruption by Magnetic Field.},
journal = {ACS applied materials &amp; interfaces},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsami.8b10972},
pmid = {30240195},
issn = {1944-8252},
abstract = {Biofilms contribute to persistent bacterial infections as well as formidable resistances to conventional antibiotics. However, it is still a major challenge to establish an advanced antibacterial nanoplatform that can efficiently eradicate biofilms while overcoming bacterial resistances. Taking advantage of the stimuli-responsive technique and the magnetic guidance strategy, here we present a highly efficient nanoplatform for planktonic inactivation and biofilm disruption. The multilayer films consisting of antibiotic Gentamicin (Gen), tannic acid (TA) and silver nanoparticles (AgNPs) were fabricated and coated on magnetic nanoparticles (MNPs) via electrostatic interactions. To achieve controlled drug release and improved biocompatibility, biodegradable hyaluronic acid (HA) was capped on the outer surface as a responsive shell. In vitro release profiles suggested that the nanocomposites showed both enzyme and pH-responsive release properties. The nanoplatform could be employed as a powerful nanocarrier for small molecular Gen and AgNPs delivery and on-demand release in response to bacterial infection microenvironment. The nanocomposites also showed satisfying antibacterial capacities against planktonic gram-positive Staphylococcus aureus and gram-negative Escherichia coli. Intriguingly, with magnetic field navigation (NdFeB, 2000 gauss), the nanocomposites could be guided to handily penetrate into S. aureus biofilm and performed dual-responsive release, showing significantly enhanced biofilm disruption. Moreover, excess reactive oxygen species (ROS) production resulting from the nanocomposites contributed to the decomposition of biofilm matrix and ultimate biofilm eradication. As a consequence, the ingenious antibacterial nanoplatform could be promising for combating biofilm infections while overcoming bacterial resistances with extra environmental factors such as magnetic field.},
}
@article {pmid30240117,
year = {2018},
author = {Jin, X and Lee, Y and Hong, SH},
title = {Canavalia ensiformis-derived lectin inhibits biofilm formation of enterohemorrhagic Escherichia coli and Listeria monocytogenes.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14108},
pmid = {30240117},
issn = {1365-2672},
abstract = {AIM: A lectin Concanavalin A (ConA) derived from Canavalia ensiformis (jack bean) exhibits high binding affinity to carbohydrates on bacterial cell surfaces. The objective of this study was to inhibit the biofilm formation of the foodborne pathogens enterohemorrhagic Escherichia coli and Listeria monocytogenes using ConA prepared by a membrane-based extraction method.<br><br>METHODS AND RESULTS: ConA was extracted using a simple and inexpensive membrane method instead of a chromatography approach. The extracted ConA was effective in inhibiting biofilms of E. coli by 30-fold and L. monocytogenes by 140-fold. In addition, ConA decreased the swimming motility of enterohemorrhagic E. coli EDL933 (EHEC) by 37%, resulting in low biofilm formation, as ConA binding to the bacterial cell surfaces might cause a reduced capability to adhere due to low cellular motility. We confirmed that the extracted ConA contains active components at less than 10 kDa as well as ConA multimers (>30 kDa) that repress EHEC biofilms. Additionally, non-cell-based mannose reduced the activity of ConA in inhibiting biofilms.<br><br>CONCLUSIONS: ConA extracted using the membrane-based method is active in inhibiting the biofilm formation by E. coli and L. monocytogenes via the mannose-binding affinity of ConA.<br><br>ConA can be used as a promising anti-adherent and anti-biofilm agent in inhibiting biofilm formation by enterohemorrhagic E. coli and L. monocytogenes. The membrane-based extraction approach may be applied for the economic production of biologically active lectins. This article is protected by copyright. All rights reserved.},
}
@article {pmid30239669,
year = {2018},
author = {Petrovich, M and Chu, B and Wright, D and Griffin, J and Elfeki, M and Murphy, BT and Poretsky, R and Wells, G},
title = {Antibiotic resistance genes show enhanced mobilization through suspended growth and biofilm-based wastewater treatment processes.},
journal = {FEMS microbiology ecology},
volume = {94},
number = {11},
pages = {},
doi = {10.1093/femsec/fiy174},
pmid = {30239669},
issn = {1574-6941},
}
@article {pmid30239106,
year = {2018},
author = {Vajjala, A and Biswas, D and Tay, WH and Hanski, E and Kline, KA},
title = {Streptolysin-induced endoplasmic reticulum stress promotes group A Streptococcal host-associated biofilm formation and necrotizing fasciitis.},
journal = {Cellular microbiology},
volume = {},
number = {},
pages = {e12956},
doi = {10.1111/cmi.12956},
pmid = {30239106},
issn = {1462-5822},
abstract = {Group A Streptococcus (GAS) is a human pathogen that causes infections ranging from mild to fulminant and life-threatening. Biofilms have been implicated in acute GAS soft-tissue infections such as necrotizing fasciitis (NF). However, most in vitro models used to study GAS biofilms have been designed to mimic chronic infections and insufficiently recapitulate in vivo conditions along with the host-pathogen interactions that might influence biofilm formation. Here we establish and characterize an in vitro model of GAS biofilm development on mammalian cells that simulates microcolony formation observed in a murine model of human NF. We show that on mammalian cells, GAS forms dense aggregates that display hallmark biofilm characteristics including a three-dimensional architecture and enhanced tolerance to antibiotics. In contrast to abiotic-grown biofilms, host-associated biofilms require the expression of secreted GAS streptolysins O and S (SLO, SLS) that induce endoplasmic reticulum (ER) stress in the host. In an in vivo mouse model, the streptolysin-null mutant is attenuated in both microcolony formation and bacterial spread, but pre-treatment of soft-tissue with an ER-stressor restores the ability of the mutant to form wild type-like microcolonies that disseminate throughout the soft tissue. Taken together, we have identified a new role of streptolysin-driven ER stress in GAS biofilm formation and NF disease progression.},
}
@article {pmid30238361,
year = {2018},
author = {Salazar-Huerta, MA and Ruiz-Ordaz, N and Galíndez-Mayer, J and García-Mena, J and Juárez-Ramírez, C},
title = {Simulation and experimental validation of a gradient feeding system for fast assessment of the kinetic behavior of a microbial consortium in a tubular biofilm reactor.},
journal = {Bioprocess and biosystems engineering},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00449-018-2009-x},
pmid = {30238361},
issn = {1615-7605},
support = {SIP-IPN 20170884//Instituto Politécnico Nacional, Mexico/ ; },
abstract = {This study deals with the mathematical simulation and experimental validation of a gradient system for the gradual change of the imidacloprid loading rate to a tubular biofilm reactor (TBR). The strategy was used for fast studies of the kinetic and stoichiometric impact caused by the increase in the pesticide loading rate in a TBR, running in plug flow regime. Seemingly, this strategy has never been used for biokinetic and stoichiometric studies in biofilm reactors. For this purpose, a mathematical model describing the substrate transient behavior Sg(t) in a concentration gradient generator system using variable volume tanks is proposed. A second model, representing the temporary variation in the loading rate of imidacloprid to an aerated equalizer tank preceding the packed zone of the TBR, is also presented. Both models were experimentally confirmed. After the treatment of the experimental data, the kinetic and stoichiometric changes occurring in the TBR, caused by the gradual increase in the imidacloprid loading rate, were readily evaluated. Although the structure of the microbial community, at the phylum level, showed similar behavior along the tubular reactor, the stress produced by the gradual increase in imidacloprid concentration had functional consequences on the mixed microbial populations which were reflected on the stoichiometric and kinetic parameters. After increasing more than five times the imidacloprid loading rate to the TBR, the imidacloprid removal efficiency decayed about 40%, and the microbial-specific removal rate of the insecticide showed a decrease of about 30%.},
}
@article {pmid30237466,
year = {2018},
author = {Aliko, A and Kamińska, M and Bergum, B and Gawron, K and Benedyk, M and Lamont, RJ and Malicki, S and Delaleu, N and Potempa, J and Mydel, P},
title = {Impact of Porphyromonas gingivalis Peptidylarginine Deiminase on Bacterial Biofilm Formation, Epithelial Cell Invasion, and Epithelial Cell Transcriptional Landscape.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {14144},
doi = {10.1038/s41598-018-32603-y},
pmid = {30237466},
issn = {2045-2322},
support = {DE022597//Foundation for the National Institutes of Health (Foundation for the National Institutes of Health, Inc.)/ ; DE011111//Foundation for the National Institutes of Health (Foundation for the National Institutes of Health, Inc.)/ ; 2014/14/E/NZ6/00162//Narodowe Centrum Nauki (National Science Centre)/ ; 2016/23/B/NZ5/011469//Narodowe Centrum Nauki (National Science Centre)/ ; },
abstract = {Peptidylarginine deiminase (PPAD) is a virulence factor unique to pathogenic Porphyromonas species, especially P. gingivalis. Mechanistically, PPAD activity, in conjunction with Arg-specific gingipains, generates protein fragments with citrullinated C-termini. Such polypeptides are potential de novo epitopes that are key drivers of rheumatoid arthritis. This process could underlie the observed clinical association between rheumatoid arthritis and periodontitis. However, the role of PPAD in host colonization by P. gingivalis and, subsequently, in triggering periodontitis is not known. Therefore, the aim of the current study was to delineate the role of PPAD in bacterial biofilm formation, and to define whether adherence to, invasion of, and host responses to bacteria of gingival keratinocytes depend on PPAD activity. We studied these aspects using PPAD-competent and PPAD-incompetent strains of P. gingivalis, and demonstrated that neither biofilm formation nor its composition was affected by PPAD activity. Similarly, flow cytometry revealed that PPAD did not impact the ability of P. gingivalis to adhere to and, subsequently, invade keratinocytes. Network analyses of gene expression patterns, however, revealed a group of host genes that were sensitive to PPAD activity (CXCL8, IL36G, CCL20, and IL1B). These genes can be categorized as potent immune modulators belonging to the interleukin 1 system, or chemoattractants of lymphocytes and neutrophils. Thus, we conclude that PPAD, although it is a potent modulator of the immune response, does not affect bacterial biofilm formation or the ability of P. gingivalis to adhere to and invade gingival epithelial cells.},
}
@article {pmid30236955,
year = {2018},
author = {Tkhilaishvili, T and Lombardi, L and Klatt, AB and Trampuz, A and Di Luca, M},
title = {Bacteriophage Sb-1 enhances antibiotic activity against biofilm, degrades exopolysaccharide matrix and targets persisters of Staphylococcus aureus.},
journal = {International journal of antimicrobial agents},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijantimicag.2018.09.006},
pmid = {30236955},
issn = {1872-7913},
abstract = {Most antibiotics have limited or no activity against bacterial biofilms, while bacteriophages has the potential to eradicate biofilms. We evaluated the capability of Staphylococcus aureus-specific bacteriophage Sb-1 to eradicate biofilm alone and in combination with different classes of antibiotics, to degrade the extracellular matrix and target persister cells. Biofilm of methicillin-resistant S. aureus (MRSA) ATCC 43300 was treated with Sb-1 alone or in (simultaneous or staggered) combination with either fosfomycin, rifampin, vancomycin, daptomycin or ciprofloxacin. The matrix was visualized by confocal fluorescent microscopy. Persister cells were treated with 104 and 107 PFU/mL Sb-1 for 3 hours in PBS, followed by CFU counting. Alternatively, bacteria were washed and incubated in fresh BHI medium and the bacterial growth assessed after further 24-hours. Pre-treatment with Sb-1 followed by the administration of sub-inhibitory concentrations of antibiotic exerted a synergistic effect in eradicating MRSA biofilm. Sb-1 determined a dose-dependent reduction of matrix exopolysaccharide. 107 PFU/mL Sb-1 showed direct killing activity on ≈ 5 × 105 CFU/mL persisters. However, even a lower titer had lytic activity when phage-treated persister cells were inoculated in fresh medium, reverting to a normal-growing phenotype. This study provides valuable data regarding the capability of Sb-1 to enhance antibiotic efficacy, exhibiting specific antibiofilm features. Its ability to degrade the MRSA polysaccharide matrix and target persister cells makes Sb-1 suitable for the therapy of biofilm-associated infections.},
}
@article {pmid30235341,
year = {2018},
author = {Beshiru, A and Igbinosa, IH and Igbinosa, EO},
title = {Biofilm formation and potential virulence factors of Salmonella strains isolated from ready-to-eat shrimps.},
journal = {PloS one},
volume = {13},
number = {9},
pages = {e0204345},
doi = {10.1371/journal.pone.0204345},
pmid = {30235341},
issn = {1932-6203},
abstract = {Salmonella species is an important foodborne pathogen with the non-typhoidal serovars such as Enteritidis and Typhimurium as the most predominant strains. This study examines the biofilm formation, phenotypic virulence factors and cell surface characteristics of Salmonella strains from ready-to-eat shrimps. The ready-to-eat shrimps were obtained from open markets between November 2016 and October 2017 in Edo and Delta States, Nigeria. The occurrence of Salmonella strains in this study was 210/1440 (14.58%) of the ready-to-eat shrimp's samples. The identified strains comprise of Salmonella Enteritidis 11, Salmonella Typhimurium 14 and other Salmonella spp. 20. The 45 identified Salmonella strains revealed the following virulence properties: swimming and swarming motility 45(100%); S-layer 39(86.67%); haemolytic activity 40(88.89%); lipase activity 43(95.56%); protease activity 43(95.56%); gelatinase production 43(95.56%); and DNA degrading activity 41(91.11%). The variation in the formation of biofilm-based on the diversity of Salmonella species was observed with higher percentage of Salmonella Typhimurium strains as strong biofilms producers under different environmental conditions. For surface hydrophobicity using bacterial adherence to hydrocarbons, 25(55.56%) were hydrophilic while 20(44.44%) were moderately hydrophobic from the 45 Salmonella isolates. Using salting aggregation test for surface hydrophobicity, all selected isolates 45(100%) was hydrophilic. Autoaggregation index for the 12 selected Salmonella isolates ranged from 15.2-47.2%, while the autoaggragation index for the 12 selected test bacteria ranged from 26.2-71.3%. Coaggragation between the 12 selected test bacteria and 12 Salmonella isolates ranged from 12.5-81.0%. The occurrence of pathogenic species of Salmonella from ready-to-eat shrimps could be detrimental to the consumers. Findings on the physiological conditions of biofilms formed by the foodborne pathogenic Salmonella and the cell surface characteristics therein are crucial for the advancement of methods for controlling Salmonella from ready-to-eat foods.},
}
@article {pmid30235145,
year = {2018},
author = {Martins, DP and Leetanasaksakul, K and Barros, MT and Thamchaipenet, A and Donnelly, W and Balasubramaniam, S},
title = {Molecular Communications Pulse-based Jamming Model for Bacterial Biofilm Suppression.},
journal = {IEEE transactions on nanobioscience},
volume = {},
number = {},
pages = {},
doi = {10.1109/TNB.2018.2871276},
pmid = {30235145},
issn = {1558-2639},
abstract = {Studies have recently shown that the bacteria survivability within biofilms is responsible for the emergence of superbugs. The combat of bacterial infections, without enhancing its resistance to antibiotics, includes the use of nanoparticles to quench the quorum sensing of these biofilm-forming bacteria. Several sequential and parallel multi-stage communication processes are involved in the formation of biofilms. In this paper, we use proteomic data from a wet lab experiment to identify the communication channels that are vital to these processes.We also identified the main proteins from each channel and propose the use of jamming signals from synthetically engineered bacteria to suppress the production of those proteins. This biocompatible technique is based on synthetic biology and enables the inhibition of biofilm formation. We analyse the communications performance of the jamming process, by evaluating the path loss for a number of conditions that include different engineered bacterial population sizes, distances between the populations and molecular signal power. Our results show that sufficient molecular pulsebased jamming signals are able to prevent the biofilm formation by creating lossy communications channels (almost -3 dB for certain scenarios). From these results, we define the main design parameters to develop a fully operational bacteria-based jamming system.},
}
@article {pmid30232623,
year = {2018},
author = {Schmidt, JC and Astasov-Frauenhoffer, M and Waltimo, T and Weiger, R and Walter, C},
title = {Influence of the amplitude of different side-to-side toothbrushes on noncontact biofilm removal.},
journal = {Clinical oral investigations},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00784-018-2633-5},
pmid = {30232623},
issn = {1436-3771},
abstract = {OBJECTIVES: To investigate the impact of the lateral deflection of toothbrush bristles (amplitude) of three side-to-side toothbrushes for noncontact biofilm removal in an artificial interdental space model.<br><br>MATERIALS AND METHODS: A three-species biofilm (Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus sanguinis) was formed in vitro on protein-coated titanium disks. A flow chamber system was combined with a static biofilm growth model. The amplitudes of three commercial side-to-side toothbrushes were evaluated by means of a dose response analysis. The amplitudes were decreased in steps (100%, 85%, 70%, 55%, and 40%). Subsequently, the biofilm-coated substrates were exposed to the toothbrushes. The biofilms were analyzed with confocal laser scanning microscope images and measured using volumetric analyses.<br><br>RESULTS: The predictability of interdental biofilm reduction differed among the toothbrushes. A lower variety in the results of repeated experiments occurred in toothbrush C compared to toothbrushes A and B. Toothbrush C obtained highest percentage of biofilm reduction by 85% of amplitude power setting (median biofilm reduction 76%). Decreasing the amplitude from 85 to 40% resulted in reduced biofilm reduction (p = 0.029). In contrast, no significance could be observed for the differences of the tested amplitudes within toothbrushes A and B (p > 0.05). Between the toothbrushes, a significant difference in interdental biofilm reduction was found between C-A (p = 0.029) and C-B (p = 0.029) with amplitude of 85%.<br><br>CONCLUSIONS: The amplitude of one of the investigated side-to-side toothbrushes affected the biofilm reduction predictably in an interdental space model.<br><br>CLINICAL RELEVANCE: Within certain toothbrushes, a specific amplitude power setting may demonstrate beneficial effects on noncontact biofilm removal.},
}
@article {pmid30231554,
year = {2018},
author = {Chan, WT and Domenech, M and Moreno-Córdoba, I and Navarro-Martínez, V and Nieto, C and Moscoso, M and García, E and Espinosa, M},
title = {The Streptococcus pneumoniaeyefM-yoeB and relBE Toxin-Antitoxin Operons Participate in Oxidative Stress and Biofilm Formation.},
journal = {Toxins},
volume = {10},
number = {9},
pages = {},
doi = {10.3390/toxins10090378},
pmid = {30231554},
issn = {2072-6651},
support = {CIBER de Enfermedades Respiratorias (CIBERES)//Instituto de Salud Carlos III/ ; SAF2012-39444-C02-01//Ministerio de Economía, Industria y Competitividad, Gobierno de España/ ; },
abstract = {Type II (proteic) toxin-antitoxin systems (TAs) are widely distributed among bacteria and archaea. They are generally organized as operons integrated by two genes, the first encoding the antitoxin that binds to its cognate toxin to generate a harmless protein⁻protein complex. Under stress conditions, the unstable antitoxin is degraded by host proteases, releasing the toxin to achieve its toxic effect. In the Gram-positive pathogen Streptococcus pneumoniae we have characterized four TAs: pezAT, relBE, yefM-yoeB, and phD-doc, although the latter is missing in strain R6. We have assessed the role of the two yefM-yoeB and relBE systems encoded by S. pneumoniae R6 by construction of isogenic strains lacking one or two of the operons, and by complementation assays. We have analyzed the phenotypes of the wild type and mutants in terms of cell growth, response to environmental stress, and ability to generate biofilms. Compared to the wild-type, the mutants exhibited lower resistance to oxidative stress. Further, strains deleted in yefM-yoeB and the double mutant lacking yefM-yoeB and relBE exhibited a significant reduction in their ability for biofilm formation. Complementation assays showed that defective phenotypes were restored to wild type levels. We conclude that these two loci may play a relevant role in these aspects of the S. pneumoniae lifestyle and contribute to the bacterial colonization of new niches.},
}
@article {pmid30230743,
year = {2016},
author = {Azmy, M and Nawar, N and Mohiedden, M and Warille, L},
title = {ELECTRON MICROSCOPIC ASSAY OF BACTERIAL BIOFILM FORMED ON INDWELLING URETHRAL CATHETERS.},
journal = {Journal of the Egyptian Society of Parasitology},
volume = {46},
number = {3},
pages = {475-484},
pmid = {30230743},
issn = {1110-0583},
abstract = {Biofilm formation on indwelling urinary catheters is a leading cause of Urinary tract infection (UTI). Presence of biofilm is associated with increased bacterial resistance to antimicrobial therapy and resultant treatment failure. The study detected a reliable method for diagnosis of biofilm formation by comparing scanning electron microscopy (SEM) and tissue culture plate method (TCP). The work was conducted on 20 urinary catheters from patients ranging from 1.5 to 85 years with catheters that remained in situ for a period of 3 to 20 days. Samples of catheters for culture and SEM and samples of urine were taken at the same time. The correlation between renal conditions and biofilm formation was not significant (p=0.336). No significant correlation (p =0.836, 0.163 respectively) was found between predisposing conditions (DM, renal insufficiency, diarrhea and impaired immunity) and development of Catheter associated urinary tract infection (CAUTI)and biofilm formation. Biofilm formation increased with duration of catheter in situ, but no significant.correlation was found (p=0.095). This could be due to small number of specimens. 9/20(45%) urine samples, 12/20(60%) catheter samples were positive by culture and 14/20(70%) catheters showed biofilm on SEM. 4/12(33.33%) organisms isolated from catheter culture produced biofilm by TCP method. 9 isolates were recovered from 9 positive urine cultures. The microorganisms isolated were non Candida albicans (3/9), E. coli (2/9), C. albicans (2/9) and Acenitobacter (2/9). 14 isolates were recovered from 12 culture- positive catheters. The organisms isolated were E.- coli (3/14), non-Candida albicans (3/14), C. albicans (2/14), C tropicalis (2/14), Acenitobacter (2/14), Klebsiella (1/14) and Enterococcus (1/14). Reduction in microbial diversity with antimicrobial use was noticed but the correlation was insignificant (p=0.317). The correlation between urine culture results as well as catheter culture results and biofilm formation by SEM were both significant (p = 0.008 &amp; 0.000 respectively). The correlation between urine culture and TCP assay was insignificant (p =0.237). Using SEM as the gold standard method for the detection of biofilm, the sensitivity, specificity; total accuracy, PPV &amp; NPV of urine culture and catheter culture were, 64.30%, 100%, 75%, 100%, 54% &amp; 85.70%, 100%, 90%, 100%, 75% respectively.},
}
@article {pmid30230671,
year = {2018},
author = {Abouelhassan, Y and Zhang, Y and Jin, S and Huigens Iii, RW},
title = {Transcript Profiling of MRSA Biofilms Treated with a Halogenated Phenazine Eradicating Agent: A Platform for Defining Cellular Targets and Pathways Critical to Biofilm Survival.},
journal = {Angewandte Chemie (International ed. in English)},
volume = {},
number = {},
pages = {},
doi = {10.1002/anie.201809785},
pmid = {30230671},
issn = {1521-3773},
abstract = {Bacterial biofilms are surface-attached communities of non-replicating bacteria innately tolerant to antibiotics. Biofilms display differential gene expression profiles and physiologies compared to their planktonic counterparts; however, the biology of biofilms remains largely unknown. Here, we used a halogenated phenazine (HP) biofilm eradicator in transcript profiling experiments (RNA-seq) to define cellular targets and pathways critical to biofilm viability. A WoPPER analysis with time course validation (RT-qPCR) revealed that HP-14 induces rapid iron starvation in MRSA biofilms, as evident by the activation of iron-acquisition gene clusters (isd, sir/sbn, hts/sfa, ferrichrome ABC transporters) in 1 hour. Serine proteases and oligopeptide transporters were also found to be up-regulated while glycolysis, arginine deiminase and urease gene clusters were down-regulated. A KEGG analysis revealed that HP-14 impacts metabolic and ABC transporter functional pathways. These findings suggest that MRSA biofilm viability relies on iron homeostasis and establishes a framework to employ next-generation therapeutics to eradicate biofilms.},
}
@article {pmid30228377,
year = {2018},
author = {Rupf, S and Laczny, CC and Galata, V and Backes, C and Keller, A and Umanskaya, N and Erol, A and Tierling, S and Lo Porto, C and Walter, J and Kirsch, J and Hannig, M and Hannig, C},
title = {Comparison of initial oral microbiomes of young adults with and without cavitated dentin caries lesions using an in situ biofilm model.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {14010},
doi = {10.1038/s41598-018-32361-x},
pmid = {30228377},
issn = {2045-2322},
support = {RU 866/2-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; HA 2718/11-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; HA 5192/7-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; },
abstract = {Dental caries is caused by acids released from bacterial biofilms. However, the in vivo formation of initial biofilms in relation to caries remains largely unexplored. The aim of this study was to compare the oral microbiome during the initial phase of bacterial colonization for individuals with (CC) and without (NC) cavitated dentin caries lesions. Bovine enamel slabs on acrylic splints were worn by the volunteers (CC: 14, NC: 13) for in situ biofilm formation (2 h, 4 h, 8 h, 1 ml saliva as reference). Sequencing of the V1/V2 regions of the 16S rRNA gene was performed (MiSeq). The relative abundances of individual operational taxonomic units (OTUs) were compared between samples from the CC group and the NC group. Random forests models were furthermore trained to separate the groups. While the overall heterogeneity did not differ substantially between CC and NC individuals, several individual OTUs were found to have significantly different relative abundances. For the 8 h samples, most of the significant OTUs showed higher relative abundances in the CC group, while the majority of significant OTUs in the saliva samples were more abundant in the NC group. Furthermore, using OTU signatures enabled a separation between both groups, with area-under-the-curve (AUC) values of ~0.8. In summary, the results suggest that initial oral biofilms provide the potential to differentiate between CC and NC individuals.},
}
@article {pmid30228240,
year = {2018},
author = {Brockman, KL and Azzari, PN and Branstool, MT and Atack, JM and Schulz, BL and Jen, FE and Jennings, MP and Bakaletz, LO},
title = {Epigenetic Regulation Alters Biofilm Architecture and Composition in Multiple Clinical Isolates of Nontypeable Haemophilus influenzae.},
journal = {mBio},
volume = {9},
number = {5},
pages = {},
doi = {10.1128/mBio.01682-18},
pmid = {30228240},
issn = {2150-7511},
abstract = {Biofilms play a critical role in the colonization, persistence, and pathogenesis of many human pathogens. Multiple mucosa-associated pathogens have evolved a mechanism of rapid adaptation, termed the phasevarion, which facilitates a coordinated regulation of numerous genes throughout the bacterial genome. This epigenetic regulation occurs via phase variation of a DNA methyltransferase, Mod. The phasevarion of nontypeable Haemophilus influenzae (NTHI) significantly affects the severity of experimental otitis media and regulates several disease-related processes. However, the role of the NTHI phasevarion in biofilm formation is unclear. The present study shows that the phasevarions of multiple NTHI clinical isolates regulate in vitro biofilm formation under disease-specific microenvironmental conditions. The impact of phasevarion regulation was greatest under alkaline conditions that mimic those known to occur in the middle ear during disease. Under alkaline conditions, NTHI strains that express the ModA2 methyltransferase formed biofilms with significantly greater biomass and less distinct architecture than those formed by a ModA2-deficient population. The biofilms formed by NTHI strains that express ModA2 also contained less extracellular DNA (eDNA) and significantly less extracellular HU, a DNABII DNA-binding protein critical for biofilm structural stability. Stable biofilm structure is critical for bacterial pathogenesis and persistence in multiple experimental models of disease. These results identify a role for the phasevarion in regulation of biofilm formation, a process integral to the chronic nature of many infections. Understanding the role of the phasevarion in biofilm formation is critical to the development of prevention and treatment strategies for these chronic diseases.IMPORTANCE Upper respiratory tract infections are the number one reason for a child to visit the emergency department, and otitis media (middle ear infection) ranks third overall. Biofilms contribute significantly to the chronic nature of bacterial respiratory tract infections, including otitis media, and make these diseases particularly difficult to treat. Several mucosa-associated human pathogens utilize a mechanism of rapid adaptation termed the phasevarion, or phasevariable regulon, to resist environmental and host immune pressures. In this study, we assessed the role of the phasevarion in regulation of biofilm formation by nontypeable Haemophilus influenzae (NTHI), which causes numerous respiratory tract diseases. We found that the NTHI phasevarion regulates biofilm structure and critical biofilm matrix components under disease-specific conditions. The findings of this work could be significant in the design of improved strategies against NTHI infections, as well as diseases due to other pathogens that utilize a phasevarion.},
}
@article {pmid30227228,
year = {2018},
author = {Capote-Bonato, F and Sakita, KM and de Oliveira, AG and Bonfim-Mendonça, PS and Crivellenti, LZ and Negri, M and Estivalet Svidzinski, TI},
title = {In vitro interaction of Candida tropicalis biofilm formed on catheter with human cells.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2018.09.029},
pmid = {30227228},
issn = {1096-1208},
abstract = {Candida tropicalis has emerged as one of the major Candida non-C. albicans species, in terms of epidemiology and virulence. Despite its virulence, C. tropicalis pathogenic mechanism has yet not been fully defined. The current study aimed to demonstrate the interaction of mature C. tropicalis ATCC 750 biofilm formed on catheter with different human cell lines. In vitro mature (72 h) C. tropicalis biofilms were produced on small catheter fragments (SCF) and were mainly composed by blastoconidia. Then, migration of yeast cells from mature biofilm to human cell surfaces (HeLa and HUVEC) was investigated. After contact with both cell lines, the surface of SCF, containing mature C. tropicalis biofilm, exhibited predominantly the filamentous form. Meanwhile, fresh biofilm formed on human cell surfaces also revealed mainly of blastoconidia involved by extracellular matrix. Total biomass and metabolic activity from the remaining biofilm on SCF surface, after direct contact with human cells, exhibited a significant reduction. Mature C. tropicalis biofilm modified its extracellular matrix components, after contact with human cells. Thus, we described for the first time an easy and simple in vitro model with catheter, which could be a powerful tool for future studies that desires to elucidate the mechanisms involved in C. tropicalis biofilm.},
}
@article {pmid30226395,
year = {2018},
author = {Chen, XF and Yu, CP and Li, S and Li, X and Liu, Q},
title = {Integration Host Factor is Essential for Biofilm formation, Extracellular enzyme, Zeamine Production and Virulence in Dickeya zeae.},
journal = {Molecular plant-microbe interactions : MPMI},
volume = {},
number = {},
pages = {},
doi = {10.1094/MPMI-04-18-0096-R},
pmid = {30226395},
issn = {0894-0282},
abstract = {Dickeya zeae is a globally important pathogenic bacterium that infects a number of crops, including rice, maize, potato, and banana. Bacterial foot rot of rice caused by D. zeae is one of the most important bacterial diseases of rice in China and some Southeast Asian countries. To investigate the functions of integration host factor (IHF) in D. zeae, we generated knockout mutants of ihfA and ihfB. Phenotypic assays showed that both the ΔihfA and ΔihfB strains had greatly reduced mobility, biofilm formation, extracellular protease and pectinase activities, and toxin production compared with the wild-type strain. In addition, the mutants did not inhibit the germination of rice seeds, failed to cause soft rot in potatoes and a hypersensitive response in tobacco, and were avirulent in rice. Quantitative reverse-transcription polymerase chain reaction analysis demonstrated that IHF positively regulates the expression of zmsA, hrpN/Y, pelA/B/C, pehX, celZ, prtG, fliC, and DGC. Electrophoretic mobility shift assays further confirmed that IhfA binds to the promoter region of the diguanylate cyclase gene and alters the levels of a second bacterial messenger, c-di-GMP, to regulate the pathogenicity or other physiological functions of D. zeae. In summary, IHF is an important integrated regulator of pathogenicity in D. zeae.},
}
@article {pmid30224941,
year = {2018},
author = {Maharjan, G and Khadka, P and Siddhi Shilpakar, G and Chapagain, G and Dhungana, GR},
title = {Catheter-Associated Urinary Tract Infection and Obstinate Biofilm Producers.},
journal = {The Canadian journal of infectious diseases &amp; medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale},
volume = {2018},
number = {},
pages = {7624857},
doi = {10.1155/2018/7624857},
pmid = {30224941},
issn = {1712-9532},
abstract = {Background: Biofilms, or colonies of uropathogen growing on the surface of indwelling medical devices, can inflict obstinate or recurring infection, thought-provoking antimicrobial therapy.<br><br>Methods: This prospective analysis included 105 urine samples from catheterized patients receiving intensive care. Ensuing phenotypic identification, antibiotic sensitivity test was performed by modified Kirby-Bauer disc diffusion method following CLSI guidelines; MDR isolates were identified according to the combined guidelines of the European Centre for Disease Prevention and Control (ECDC) and the Centers for Disease Control and Prevention (CDC). Biofilm-forming uropathogens were detected by the tissue culture plate (TCA) method.<br><br>Results: The predominant uropathogen in catheter-associated UTIs (CAUTIs) was Escherichia coli 57%, followed by Klebsiella pneumonia 15%, Pseudomonas aeruginosa 12%, Staphylococcus aureus 8%, Enterobacter spp. 3%, Enterococcus faecalis, Acinetobacter spp., and Proteus mirabilis 1.5%, of which 46% isolates were biofilm producers. Prime biofilm producers were Escherichia coli 33%, followed by Klebsiella pneumoniae 30%, Pseudomonas aeruginosa 20%, Staphylococcus aureus 10%, Acinetobacter, and Enterobacter 3.33%. Multidrug resistance associated with biofilm producers were greater than biofilm nonproducers. The Gram-negative biofilm producers found 96.15%, 80.76%, 73.07%, 53.84%, 53.84%, 46.15%, 19.23%, and 11.5% resistant to amoxyclave, ceftazidime, tetracycline, gentamicin, meropenem, nitrofurantoin, amikacin, imipenem, and fosfomycin, respectively. Gram-positive biofilm producers, however, were found 100% resistant to tetracycline, cloxacillin, and amoxyclave: 66.67% resistant to ampicillin while 33.33% resistant to gentamicin, ciprofloxacin, and nitrofurantoin.<br><br>Conclusion: High antimicrobial resistance was observed in biofilm producers than non-biofilm producers. Of recommended antimicrobial therapies for CAUTIs, ampicillin and amoxicillin-clavulanate were the least active antibiotics, whereas piperacillin/tazobactam and imipenem were found as the most effectual for gram-negative biofilm producer. Likewise, amoxicillin-clavulanate and tetracycline were the least active antibiotics, whereas vancomycin, fosfomycin, piperacillin-tazobactam, and meropenem were found as the most effective antibiotic for Gram-positive biofilm producer. In the limelight, the activity fosfomycin was commendable against both Gram-positive and Gram-negative biofilm producers.},
}
@article {pmid30224574,
year = {2018},
author = {Ramalingam, K and Lee, V},
title = {Biotic and abiotic substrates for enhancing Acinetobacter baumannii biofilm formation: New approach using extracellular matrix and slanted coverslip technique.},
journal = {The Journal of general and applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.2323/jgam.2018.05.004},
pmid = {30224574},
issn = {1349-8037},
abstract = {Acinetobacter baumannii has been well recognized as a problematic human pathogen and several reports has shown the incidence of multidrug and pandrug-resistant A. baumannii strains in infirmary infections. A. baumannii grows only on an air-liquid interface and does not form a contiguous biofilm. Extracellular matrices (ECM) and slanted glass coverslips are (SGC) used as biofilm substrates and biofilms have been investigated by SEM, confocal and crystal violet staining. ECM has shown enhanced biofilm formation under dynamic conditions rather than static conditions. SGC biofilm yield assay has shown higher levels of continuous layers and packed thicker biofilm formation with glass coverslip inserts, up to 1.7 to 3 times higher biofilm formation, than when compared with no glass coverslip inserts. A media immersed ECM study revealed that biofilm grown on extracellular matrixes formed thread-like pili structures, and that these structures had contact with the ECM and also showed excellent cell-to-cell interaction. In summary, A. baumannii showed higher biofilm formation capacities with ECM, while the prominent results were directly related with the biofilm formation capacity of A. baumannii. For the initial step of biofilm formation, adherence is an important factor and, consequently, strains with a comparatively high capability to adhere to extracellular matrices and slanted glass coverslips provide a new method of enhanced biofilm growth for in vitro assays. ECM can be used as a substrate for immersed biofilm formation studies and the SGC method for air-liquid interface exposed biofilm formation studies, and these substrates can provide better biofilm growth and easy handling for in vitro adherence and biofilm assays.},
}
@article {pmid30224496,
year = {2018},
author = {Mukherjee, S and Moustafa, DA and Stergioula, V and Smith, CD and Goldberg, JB and Bassler, BL},
title = {The PqsE and RhlR proteins are an autoinducer synthase-receptor pair that control virulence and biofilm development in Pseudomonas aeruginosa.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {},
number = {},
pages = {},
doi = {10.1073/pnas.1814023115},
pmid = {30224496},
issn = {1091-6490},
abstract = {Pseudomonas aeruginosa is a leading cause of life-threatening nosocomial infections. Many virulence factors produced by P. aeruginosa are controlled by the cell-to-cell communication process called quorum sensing (QS). QS depends on the synthesis, release, and groupwide response to extracellular signaling molecules called autoinducers. P. aeruginosa possesses two canonical LuxI/R-type QS systems, LasI/R and RhlI/R, that produce and detect 3OC12-homoserine lactone and C4-homoserine lactone, respectively. Previously, we discovered that RhlR regulates both RhlI-dependent and RhlI-independent regulons, and we proposed that an alternative ligand functions together with RhlR to control the target genes in the absence of RhlI. Here, we report the identification of an enzyme, PqsE, which is the alternative-ligand synthase. Using biofilm analyses, reporter assays, site-directed mutagenesis, protein biochemistry, and animal infection studies, we show that the PqsE-produced alternative ligand is the key autoinducer that promotes virulence gene expression. Thus, PqsE can be targeted for therapeutic intervention. Furthermore, this work shows that PqsE and RhlR function as a QS-autoinducer synthase-receptor pair that drives group behaviors in P. aeruginosa.},
}
@article {pmid30224144,
year = {2018},
author = {Jiang, Z and Zhang, D and Zhou, L and Deng, D and Duan, M and Liu, Y},
title = {Enhanced catalytic capability of electroactive biofilm modified with different kinds of carbon nanotubes.},
journal = {Analytica chimica acta},
volume = {1035},
number = {},
pages = {51-59},
doi = {10.1016/j.aca.2018.06.077},
pmid = {30224144},
issn = {1873-4324},
abstract = {In this study two methods including coating carbon nanotubes (CNTs) layers on the electrode surface and adding CNTs-suspension during electrochemically active biofilms (EABs) growth were used, respectively, to develop CNTs hybrid EABs for enhancing electricity generation capability of EABs. EABs growth on the CNTs with functional groups of hydroxyl (CNTs-OH) or carboxyl (CNTs-COOH) and pristine CNTs without functionalization (P-CNTs) modified electrode was investigated. The maximum current densities of EABs growth on the P-CNTs, CNTs-OH and CNTs-COOH coated electrode were respective 1300 ± 117, 1082 ± 54 and 1124 ± 78 μA cm-2, which were much higher than unmodified electrode (663 μA cm-2). Meanwhile, EABs growth in doping CNTs-COOH or CNTs-OH suspensions system also produced twice higher current density than that on unmodified electrode. These results indicated that the current production of EABs can be significantly enhanced by coating P-CNTs, CNTs-OH, CNTs-COOH layers on the electrode surface or doping CNTs-OH and CNTs-COOH suspension into EABs. Furthermore, morphology analysis of as-obtained EABs had also been studied. It was found that there was no significant difference of the morphological characteristic for EABs growth on different types CNTs coated electrode surface. By comparison, a nano-hybrid porous structure of CNTs and EABs was observed when CNTs-COOH or CNTs-OH suspension was added into the medium during EABs growth, which will be responsible for high current generation.},
}
@article {pmid30223164,
year = {2018},
author = {Vaigankar, DC and Dubey, SK and Mujawar, SY and D'Costa, A and S K, S},
title = {Tellurite biotransformation and detoxification by Shewanella baltica with simultaneous synthesis of tellurium nanorods exhibiting photo-catalytic and anti-biofilm activity.},
journal = {Ecotoxicology and environmental safety},
volume = {165},
number = {},
pages = {516-526},
doi = {10.1016/j.ecoenv.2018.08.111},
pmid = {30223164},
issn = {1090-2414},
abstract = {Tellurite reducing bacterial strain was isolated from Zuari estuary, Goa India which could tolerate 5.5 mM potassium tellurite with a minimum inhibitory concentration of 6 mM. This strain was designated as GUSDZ9 and was identified as Shewanella baltica (accession number: MF350629) based on 16S rRNA gene sequencing and BLAST analysis. The Diethyl-dithiocarbamate based colorimetric analysis clearly demonstrated a complete reduction of 2 mM tellurite to elemental tellurium during the late stationary phase. Te Nanoparticles (TeNPs) biosynthesis which initiated at early log phase (i.e. 4 h) was evidently monitored through colour change and a peak due to surface plasmon resonance at 210 nm using UV-Vis spectroscopic analysis. X-ray crystallographic studies and transmission electron microscopy revealed unique nano-rods with a diameter ranging from 8 to 75 nm. Energy dispersive X-ray analysis further confirmed the presence of pure tellurium. The biogenic TeNPs at 10 and 5 µg/mL evidently demonstrated 90% degradation of methylene blue dye and anti-biofilm activity against potential Gram-positive and Gram-negative human pathogens respectively. The alkaline comet assay revealed time and dose-dependent genotoxicity at concentrations higher than 15 µg/mL of TeNPs. This study clearly demonstrated the potential of Shewanella baltica strain GUSDZ9 in bioremediation of toxic tellurite through bio-reduction into elemental tellurium and involvement of biogenic TeNPs in the photo-catalytic reduction of methylene blue and anti-biofilm activity. This is the first report of its kind on the synthesis of biogenic TeNPs from Shewanella baltica demonstrating photo-catalytic, anti-biofilm activity as well as genotoxicity.},
}
@article {pmid30221799,
year = {2018},
author = {Hongman, H and Yifang, W and Gongliang, Z and Yaolei, Z and Longquan, X and Hongshun, H and Yue, W and Meishan, L},
title = {Effects of Sulfide Flavors on AHL-Mediated Quorum Sensing and Biofilm Formation of Hafnia alvei.},
journal = {Journal of food science},
volume = {},
number = {},
pages = {},
doi = {10.1111/1750-3841.14345},
pmid = {30221799},
issn = {1750-3841},
support = {2017YFC1600403//The National Key R&amp; D Program of China/ ; 201602049//The Science and Technology Foundation of Liaoning Province/ ; },
abstract = {In this study, 10 different sulfide flavor compounds commonly used as food additives were screened for antiquorum-sensing activity. Among these, diallyl disulfide (DADS) and methyl 2-methyl-3-furyl disulfide (MMFDS) were found to exert the strongest inhibition against violacein production in Chromobacterium violaceum 026, the tested biosensor strain. DADS and MMFDS also inhibited the growth of Hafnia alvei H4, yielding MIC values of 48 and 41.6 mM, respectively. In addition, DADS and MMFDS also inhibited the ability of H. alvei H4 to produce acyl-homoserine lactone as demonstrated by the reduced level of C6-HSL in the supernatant of DADS-treated culture. At concentrations corresponding to 1/4 MIC, DADS, and MMFDS inhibited the swarming ability of H. alvei H4 by 73.50% and 76.43%, respectively, while having virtually no effect on cell growth. The same concentrations of DADS and MMFDS also completely inhibited the formation of biofilm. These antiquorum sensing effects of DADS and MMFDS involved changes in the expression of the quorum-sensing genes luxI and luxR. Quantitative RT-PCR analysis showed that the mRNA levels of both genes were significantly reduced by DADS and MMDFS at concentrations below their MICs. However, further test using a mutant strain of H. alvei lacking luxR (ΔluxR) revealed significant reduction in luxI mRNA level upon treatment of the strain with DADS or MMDFS, but no change in luxR mRNA level occurred when a luxI-lacking mutant (ΔluxI) was treated with these compounds. The result therefore suggested that the antiquorum-sensing effect of DADS and MMFDS against H. alvei H4 might operate mainly through the inhibition of luxI expression in the cells.<br><br>PRACTICAL APPLICATION: The sulfide flavors compounds used in this paper are commonly used in food processing in China and are listed in the national standard of Chinese food additives GB2760-2014. The application of sulfide flavors in food processing can enhance aroma and prevent food spoilage.},
}
@article {pmid30221325,
year = {2018},
author = {Raskov, H and Kragh, KN and Bjarnsholt, T and Alamili, M and Gögenur, I},
title = {Bacterial biofilm formation inside colonic crypts may accelerate colorectal carcinogenesis.},
journal = {Clinical and translational medicine},
volume = {7},
number = {1},
pages = {30},
doi = {10.1186/s40169-018-0209-2},
pmid = {30221325},
issn = {2001-1326},
abstract = {BACKGROUND: Research in the field of relation between microbes and colorectal carcinogenesis has gained increasing interest in past years. Recently, link between microbial biofilm and carcinogenesis in colon was demonstrated by several authors indicating that biofilm not only is a key player in carcinogenesis, but also may contribute to the understanding of side-specific colon cancer-right sided colon cancer versus left sided. In this article, we briefly highlight the major findings of the research of biofilm and carcinogenesis and demonstrate our findings of colonic cancer tissue and colonic polyp examined for biofilm.<br><br>CASE PRESENTATION: Colonic cancer tissue from a patient with a right-sided colon cancer, and an adenoma tubular polyp were examined for biofilm formation by flourescens in situ hybridization. In cancer tissue we found biofilm formation on the surface epithelium but surprisingly also deep into the crypts. No biofilms were found in tubular polyp tissue.<br><br>CONCLUSIONS: To our knowledge, this is the first-time biofilm formation deep into colonic crypts are demonstrated in a patient with right-sided colon cancer. This may indicate that bacterial biofilm may have a key role in carcinogenesis.},
}
@article {pmid30221220,
year = {2018},
author = {Roselló, J and Giménez, S and Ibáñez, MD and Blázquez, MA and Santamarina, MP},
title = {Bomba Rice Conservation with a Natural Biofilm.},
journal = {ACS omega},
volume = {3},
number = {3},
pages = {2518-2526},
doi = {10.1021/acsomega.7b01804},
pmid = {30221220},
issn = {2470-1343},
abstract = {The chemical composition of commercial Syzygium aromaticum, Cinnamomum verum, and Laurus nobilis essential oils as well as their antifungal activity against four pathogenic fungi isolated from Mediterranean rice grains has been investigated. Eighty nine compounds accounting for between 98.5 and 99.4% of the total essential oil were identified. The phenylpropanoids eugenol (89.37 ± 0.29%) and eugenol (56.34 ± 0.41%), followed by eugenol acetate (19.48 ± 0.13%) were, respectively, the main compounds in clove and cinnamon essential oils, whereas large amounts of the oxygenated monoterpenes 1,8-cineole (58.07 ± 0.83%) and α-terpinyl acetate (13.05 ± 0.44%) were found in bay leaf essential oil. Clove and cinnamon oils showed the best antifungal activity results against all tested fungi. Against Alternaria alternata, clove essential oil displayed the best antifungal effect, whereas against Curvularia hawaiiensis, cinnamon essential oil was more active. Both essential oils showed a similar antifungal effect towards Fusarium proliferatum and Fusarium oxysporum. In vitro studies in inoculated rice grains showed that clove and cinnamon totally inhibited pathogenic fungal development after 30 days of incubation. In vivo studies showed that eugenol used with a polysaccharide such as agar-agar formed a fine coat which wraps the inoculated rice grains, creating a natural biofilm and reducing the development of all pathogenic fungi (80-95%) for 30 days.},
}
@article {pmid30221108,
year = {2018},
author = {Aumeeruddy-Elalfi, Z and Ismaël, IS and Hosenally, M and Zengin, G and Mahomoodally, MF},
title = {Essential oils from tropical medicinal herbs and food plants inhibit biofilm formation in vitro and are non-cytotoxic to human cells.},
journal = {3 Biotech},
volume = {8},
number = {9},
pages = {395},
doi = {10.1007/s13205-018-1413-x},
pmid = {30221108},
issn = {2190-572X},
abstract = {The biofilm inhibition and eradication potential of essential oils (EOs) extracted from six tropical medicinal herbs and food plants [Psiadia arguta (PA), Psiadia terebinthina (PT), Citrus grandis (CGp), Citrus hystrix (CH), Citrus reticulata (CR), and Cinnamomum zeylanicum (CZ)] were assessed. The mechanism of inhibition was studied via quenching of efflux pump. Cytotoxicity was evaluated using Artemia salina assay and cell lines [human cervix carcinoma (HeLa), human lung fibroblast (MRC-5), and murine melanoma (B16F10)]. EOs of CH, CR, PA, and PT were found to be prospective antibiofilm agents (IC50 of 0.29, 0.59, 0.22, and 0.11 mg/mL against Staphylococcus epidermidis; 0.39, 0.54, 0.09, and 0.13 mg/mL against Escherichia coli; and 0.54, 0.90, 0.44 and 0.51 mg/mL against Candida albicans for CH, CR, PA, and PT, respectively). The simultaneous actions of the EOs and efflux pump inhibitor impacted on the resistance of the biofilms. LC50 of the EOs ranged from 223 to 583 µg/mL against A. salina. The non-cytotoxic concentration of the EOs varied from 200 to 300 µg/mL (HeLa and MRC-5), and 150-200 µg/mL (B16F10). EOs from these tropical medicinal herbs and food plants are useful sources of new antimicrobials with low cytotoxicity which could open new horizons in the drug development process.},
}
@article {pmid30220506,
year = {2018},
author = {Astasov-Frauenhoffer, M and Glauser, S and Fischer, J and Schmidli, F and Waltimo, T and Rohr, N},
title = {Biofilm formation on restorative materials and resin composite cements.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.dental.2018.08.300},
pmid = {30220506},
issn = {1879-0097},
abstract = {OBJECTIVES: Monolithic zirconia, polymer-infiltrated ceramic and acrylate polymer cemented with resin composite cement have recently been identified as prosthetic treatment options for zirconia implants. The aim of the present study is to determine in vitro, to what extent bacteria adhere to these materials.<br><br>METHODS: Disks made of zirconia (Vita YZ [YZ]), polymer-infiltrated ceramic (Vita Enamic [VE]), acrylate polymer (Vita CAD-Temp [CT]), self-adhesive cement (RelyX Unicem 2 Automix [RUN]) and of two different adhesive cements (RelyX Ulimate [RUL] and Vita Adiva F-Cem [VAF]) were produced. The biofilm formation of three bacterial species (Streptococcus sanguinis, Fusobacterium nucleatum, Porphyromonas gingivalis) on each material was assessed over 72h using a flow chamber system. The biofilms were quantified by crystal violet staining (optical density 595nm) and visualized using SEM. The inorganic composition of the different materials was analyzed and the wettability of the specimens was measured.<br><br>RESULTS: For the restorative materials lowest biofilm formation was found on CT: OD 0.5±0.1, followed by VE: OD 0.8±0.1 and YZ: OD 1.4±0.3. The biofilm formation on resin composite cements was significantly lower on VAF: OD 0.6±0.1 than for RUL: OD 0.9±0.1 and RUN: OD 1.0±0.1. A high wettability of the specimens with saliva/serum mixture tended to result in a higher biofilm formation. Correlations were obtained between the organic/inorganic composition of the materials and the polar/dispersive part of the surface free energy.<br><br>SIGNIFICANCE: Three-species biofilm formation on restorative and cement materials strongly relies on the materials composition. If the restorative material CT and cement VAF also prevent excessive biofilm formation in a clinical situation should be further investigated.},
}
@article {pmid30220065,
year = {2018},
author = {Benedek, T and Szentgyörgyi, F and Szabó, I and Kriszt, B and Révész, F and Radó, J and Maróti, G and Táncsics, A},
title = {Aerobic and oxygen-limited enrichment of BTEX-degrading biofilm bacteria: dominance of Malikia versus Acidovorax species.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-018-3096-6},
pmid = {30220065},
issn = {1614-7499},
abstract = {Due to their high resistance against environmental challenges, bacterial biofilms are ubiquitous and are frequently associated with undesired phenomena in environmental industry (e. g. biofouling). However, because of the high phylogenetic and functional diversity, bacterial biofilms are important sources of biotechnologically relevant microorganisms, e.g. those showing bioremediation potential. In our previous work, the high phylogenetic and metabolic diversity of a clogging biofilm, developed in a simple aromatic hydrocarbon (BTEX)-contaminated groundwater well was uncovered. The determination of relationships between different groups of biofilm bacteria and certain metabolic traits has been omitted so far. Therefore, by setting up new biofilm-based enrichment microcosms, the research goal of the present study was to identify the aerobic/hypoxic BTEX-degrading and/or prolific biofilm-forming bacteria. The initial bacterial community composition as well as temporal dynamics due to the selective enrichment has been determined. The obtained results indicated that the concentration of dissolved oxygen may be a strong selective force on the evolution and final structure of microbial communities, developed in hydrocarbon-contaminated environments. Accordingly, members of the genus Malikia proved to be the most dominant community members of the aerobic BTEX-degrading enrichments. Acidovorax spp. dominated the oxygen-limited/hypoxic setup. During the study, a strain collection of 23 different bacterial species was obtained. Non-pathogenic members of this strain collection, with outstanding biodegradation (e.g. Pseudomonas, Variovorax isolates) and biofilm-forming potential (e.g. Rhizobium), may potentially be applied in the development of biofilm-based semipermeable reactive biobarriers.},
}
@article {pmid30218931,
year = {2018},
author = {Han, F and Ye, W and Wei, D and Xu, W and Du, B and Wei, Q},
title = {Simultaneous nitrification-denitrification and membrane fouling alleviation in a submerged biofilm membrane bioreactor with coupling of sponge and biodegradable PBS carrier.},
journal = {Bioresource technology},
volume = {270},
number = {},
pages = {156-165},
doi = {10.1016/j.biortech.2018.09.026},
pmid = {30218931},
issn = {1873-2976},
abstract = {Simultaneous nitrification-denitrification (SND) was achieved in submerged biofilm membrane bioreactor (SBF-MBR) treating low carbon/nitrogen (C/N) ratio wastewater. A novel bio-carrier coupling of sponge and biodegradable poly(butanediol succinate) (PBS) was applied as external carbon source and biofilm carrier. Result represented that NH4+-N and total nitrogen removal efficiencies were high of 99.1% and 94.3% in the SBF-MBR. Protein (PN) contents from SND-biofilm were reduced by 10.5% and 44.3% in TB-EPS and LB-EPS, while polysaccharides (PS) were reduced by 45.8% and 34.8%, respectively. 3D-EEM spectra indicated that protein-like, humic acid-like and fulvic acid-like substances were the main components in EPS and their peak intensities were reduced. Additionally, membrane fouling of SBF-MBR was improved after the achievement of biofilm. Microbial community analysis showed that Simplicispira, Thauera, Desulfovibrio, Dechlorobacter and Acinetobacter were dominant genus, which indicated co-existence of nitrifying bacteria, heterotrophic denitrifiers and aerobic denitrifiers in the SBF-MBR.},
}
@article {pmid30218926,
year = {2018},
author = {Zhang, X and Prévoteau, A and Louro, RO and Paquete, CM and Rabaey, K},
title = {Periodic polarization of electroactive biofilms increases current density and charge carriers concentration while modifying biofilm structure.},
journal = {Biosensors &amp; bioelectronics},
volume = {121},
number = {},
pages = {183-191},
doi = {10.1016/j.bios.2018.08.045},
pmid = {30218926},
issn = {1873-4235},
abstract = {Anodic electroactive biofilms (EABs) need to overcome low current densities for applications such as microbial fuel cells or biosensors. EABs can store charge in self-produced redox proteins when temporarily left in open circuit, and discharge them once the electrode is appropriately repolarized, thus behaving as pseudocapacitors. Here we investigated the effect of such periodic polarization on the intrinsic nature of the EABs during their entire growth (i.e. starting from inoculation and for 10 days) on glassy carbon electrodes. An optimal periodic polarization (half-period of 10 s) greatly increased the maximum steady-state current density delivered by the Geobacter-dominated EABs (up to 1.10 ± 0.02 mA cm-2, n = 3 electrodes) when compared to continuously polarized EABs (0.41 ± 0.04 mA cm-2); and increased the amount of electric charges produced per hour by 69 ± 17% even taking into account the half-periods of open circuit. This enhancement was highly correlated with a substantial increase in charge carriers concentration (10.6 ± 0.5 mMe- vs. 2.9 ± 0.6 mMe-), allowing higher charge storage capacity and higher electron mobility across the EABs. Our results suggest that appropriate periodic polarizations may upregulate the expression of heme-containing redox proteins associated with the matrix, such as c-type cytochromes. The EABs grown under periodic polarization presented mushroom-like structures on their top layers, while EABs grown under continuous polarization were flat.},
}
@article {pmid30218533,
year = {2018},
author = {Keeney, K and Trmcic, A and Zhu, Z and Delaquis, P and Wang, S},
title = {Stress Survival Islet 1 Contributes to Serotype-specific Differences in Biofilm Formation in Listeria monocytogenes.},
journal = {Letters in applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/lam.13072},
pmid = {30218533},
issn = {1472-765X},
abstract = {Listeria monocytogenes has a significant impact on the food industry by forming biofilms on food-processing equipment. Tandem analysis of whole-genome sequencing data with biofilm data from 166 environmental and food-related L. monocytogenes isolates has revealed serotypic and genetic factors that strongly correlate with adherence and biofilm formation, such as lineage, plasmid harborage, a three codon-deletion in inlA and the presence of the Stress Survival Islet 1 (SSI-1). Strains from serotype 1/2b, the majority of which contained SSI-1, formed the strongest biofilms, while serotype 4b strains, the majority of which did not contain SSI-1, formed the weakest biofilms. When serotype 1/2a was separated by its SSI-1 genotype, SSI-1 positive 1/2a strains demonstrated significantly higher capacity for biofilm formation after 3 days of growth at 30°C (p<0.0001). Together, these findings indicate that SSI-1 may contribute to serotype-associated differences in the biofilm-forming capacity in L. monocytogenes. This article is protected by copyright. All rights reserved.},
}
@article {pmid30218375,
year = {2018},
author = {Mahdinia, E and Demirci, A and Berenjian, A},
title = {Implementation of fed-batch strategies for vitamin K (menaquinone-7) production by Bacillus subtilis natto in biofilm reactors.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-018-9340-7},
pmid = {30218375},
issn = {1432-0614},
support = {PEN04561-1002249//USDA National Institute of Food and Agriculture Federal Appropriations/ ; },
abstract = {Recent studies show the essential health benefits associated with vitamin K, especially menaquinone-7 (MK-7). These benefits include reducing risks of cardiovascular diseases, osteoporosis, and even cancer. However, MK-7 production on an industrial level is only possible through bacterial fermentation and also current static fermentation strategies are not potent enough with difficulties to scale up. Biofilm reactors, however, may be a practical alternative. Biofilm reactors provide a controlled environment for the microorganisms to form mature and robust biofilms that enable them to produce value-added products with enhanced efficiencies. In this study, fed-batch addition of glucose and glycerol were investigated to the base media in biofilm reactors, as carbon source addition seemed crucial in batch fermentations. Results indicated that fed-batch strategies can be significantly effective in glucose-based medium, increasing the end-product concentrations to 28.7 ± 0.3 mg/L of MK-7 which was 2.3 fold higher than the level produced in suspended-cell bioreactors and renders the biofilm reactors as a potential replacement for static fermentation strategies. Moreover, morphological changes of B. subtilis were tracked during the 12-day long fermentation runs and finally, SEM investigations confirmed significant biofilm and extracellular matrices formed on the plastic composite support (PCS) in the biofilm reactors. In conclusion, biofilm reactors especially with fed-batch fermentation regimes seem to be an effective tool for MK-7 production at industrial scales.},
}
@article {pmid30218278,
year = {2018},
author = {Latif, M and May, EE},
title = {A Multiscale Agent-Based Model for the Investigation of E. coli K12 Metabolic Response During Biofilm Formation.},
journal = {Bulletin of mathematical biology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11538-018-0494-3},
pmid = {30218278},
issn = {1522-9602},
support = {MCB-1445470//Division of Molecular and Cellular Biosciences/ ; FA8650-10-2-6062//Defense Threat Reduction Agency/ ; Office of Science Graduate Student Research (SCGSR) Award//Office of Science/ ; },
abstract = {Bacterial biofilm formation is an organized collective response to biochemical cues that enables bacterial colonies to persist and withstand environmental insults. We developed a multiscale agent-based model that characterizes the intracellular, extracellular, and cellular scale interactions that modulate Escherichia coli MG1655 biofilm formation. Each bacterium's intracellular response and cellular state were represented as an outcome of interactions with the environment and neighboring bacteria. In the intracellular model, environment-driven gene expression and metabolism were captured using statistical regression and Michaelis-Menten kinetics, respectively. In the cellular model, growth, death, and type IV pili- and flagella-dependent movement were based on the bacteria's intracellular state. We implemented the extracellular model as a three-dimensional diffusion model used to describe glucose, oxygen, and autoinducer 2 gradients within the biofilm and bulk fluid. We validated the model by comparing simulation results to empirical quantitative biofilm profiles, gene expression, and metabolic concentrations. Using the model, we characterized and compared the temporal metabolic and gene expression profiles of sessile versus planktonic bacterial populations during biofilm formation and investigated correlations between gene expression and biofilm-associated metabolites and cellular scale phenotypes. Based on our in silico studies, planktonic bacteria had higher metabolite concentrations in the glycolysis and citric acid cycle pathways, with higher gene expression levels in flagella and lipopolysaccharide-associated genes. Conversely, sessile bacteria had higher metabolite concentrations in the autoinducer 2 pathway, with type IV pili, autoinducer 2 export, and cellular respiration genes upregulated in comparison with planktonic bacteria. Having demonstrated results consistent with in vitro static culture biofilm systems, our model enables examination of molecular phenomena within biofilms that are experimentally inaccessible and provides a framework for future exploration of how hypothesized molecular mechanisms impact bulk community behavior.},
}
@article {pmid30217836,
year = {2018},
author = {Xue, D and Tian, F and Yang, F and Chen, H and Yuan, X and Yang, CH and Chen, Y and Wang, Q and He, C},
title = {Phosphodiesterase EdpX1 promotes virulence, exopolysaccharide production and biofilm formation in Xanthomonas oryzae pv. oryzae.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.01717-18},
pmid = {30217836},
issn = {1098-5336},
abstract = {In Xanthomonas oryzae pv. oryzae (Xoo), the bacterial blight pathogen of rice, there are over twenty genes encoding GGDEF, EAL or HD-GYP domains, which are potentially involved in the metabolism of second messenger c-di-GMP. In this study, we focused on characterization of an EAL-domain protein EdpX1. Deletion of edpX1 resulted in a two-fold increase of the intracellular c-di-GMP levels, which was restored to the wild-type levels in the complemented strain ΔedpX1(pB-edpX1), demonstrating EdpX1 is an active phosphodiesterase (PDE) in Xoo. In addition, colorimetric assays further confirmed the PDE activity of EdpX1 by showing that mutation of E153A at the EAL motif strongly reduced its activity. Virulence assays on the leaves of susceptible rice showed that ΔedpX1 was severely impaired in causing disease symptoms. In trans expression of wild-type edpX1, but not edpX1E153A, was able to complement the weakened virulence phenotype. These results indicated that an active EAL domain is required for EdpX1 to regulate the virulence of Xoo. We then demonstrated that ΔedpX1 was defective in secreting exopolysaccharide (EPS) and forming biofilm. Expression of edpX1 in ΔedpX1, but not edpX1E153A restored the defective phenotypes to near wild-type level. In addition, we observed that EdpX1-GFP exhibited multiple subcellular localization foci, and this pattern was dependent on its transmembrane (TM) region, which did not seem to directly contribute to the regulatory function of EdpX1. Thus, we concluded that EdpX1 exhibits PDE activity to control c-di-GMP level, and its EAL domain is necessary and sufficient for its regulation on virulence in Xoo.IMPORTANCE Bacteria utilize c-di-GMP as a second messenger to regulate various biological functions. The synthesis and degradation of c-di-GMP are catalyzed by GGDEF domains and EAL or HD-GYP domains, respectively. Multiple genes encoding these domains are often found in one bacterial strain. For example, in the genome of Xoo PXO99A, 26 genes encoding proteins containing these domains were identified. Therefore, to fully appreciate the complexity and specificity of c-di-GMP signaling in Xoo, the enzymatic activities and regulatory functions of each GGDEF, EAL and HD-GYP domain proteins need to be elucidated. In this study, we showed the EAL-domain protein EdpX1 is a major PDE to regulate diverse virulence phenotypes through the c-di-GMP signaling pathway.},
}
@article {pmid30217006,
year = {2018},
author = {Kamaruzzaman, NF and Tan, LP and Mat Yazid, KA and Saeed, SI and Hamdan, RH and Choong, SS and Wong, WK and Chivu, A and Gibson, AJ},
title = {Targeting the Bacterial Protective Armour; Challenges and Novel Strategies in the Treatment of Microbial Biofilm.},
journal = {Materials (Basel, Switzerland)},
volume = {11},
number = {9},
pages = {},
doi = {10.3390/ma11091705},
pmid = {30217006},
issn = {1996-1944},
abstract = {Infectious disease caused by pathogenic bacteria continues to be the primary challenge to humanity. Antimicrobial resistance and microbial biofilm formation in part, lead to treatment failures. The formation of biofilms by nosocomial pathogens such as Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), and Klebsiella pneumoniae (K. pneumoniae) on medical devices and on the surfaces of infected sites bring additional hurdles to existing therapies. In this review, we discuss the challenges encountered by conventional treatment strategies in the clinic. We also provide updates on current on-going research related to the development of novel anti-biofilm technologies. We intend for this review to provide understanding to readers on the current problem in health-care settings and propose new ideas for new intervention strategies to reduce the burden related to microbial infections.},
}
@article {pmid30216921,
year = {2018},
author = {Lan, M and Li, M and Liu, J and Quan, X and Li, Y and Li, B},
title = {Coal chemical reverse osmosis concentrate treatment by membrane-aerated biofilm reactor system.},
journal = {Bioresource technology},
volume = {270},
number = {},
pages = {120-128},
doi = {10.1016/j.biortech.2018.09.011},
pmid = {30216921},
issn = {1873-2976},
abstract = {Coal chemical reverse osmosis concentrate (ROC), which is characterized by high salinity and high organics, remains as a serious environmental problem. In this study, a lab-scale three-stage membrane-aerated biofilm reactor (MABR) system was designed to treat such a ROC. The effects of influent salinity and operating parameters (pH, DO and HRT) on the treatment efficiency were discussed. The removal efficiencies of COD, NH4-N and TN under the optimal operating parameters reached to 81.01%, 92.31% and 70.72%, respectively. Simultaneous nitrification and denitrification (SND) as well as shortcut nitrogen removal were achieved. The salinity less than 3% did not induce significant decrease in treatment efficiency and microbial communities. Moreover, the dominant phyla in biofilms were Proteobacteria and Bacteroidetes. This work demonstrated MABR had great potential in ROC treatment.},
}
@article {pmid30216370,
year = {2018},
author = {Yu, Z and Deslouches, B and Walton, WG and Redinbo, MR and Di, YP},
title = {Enhanced biofilm prevention activity of a SPLUNC1-derived antimicrobial peptide against Staphylococcus aureus.},
journal = {PloS one},
volume = {13},
number = {9},
pages = {e0203621},
doi = {10.1371/journal.pone.0203621},
pmid = {30216370},
issn = {1932-6203},
abstract = {SPLUNC1 is a multifunctional protein of the airway with antimicrobial properties. We previously reported that it displayed antibiofilm activities against P. aeruginosa. The goal of this study was to determine whether (1) the antibiofilm property is broad (including S. aureus, another prevalent organism in cystic fibrosis); (2) the α4 region is responsible for such activity; and (3), if so, this motif could be structurally optimized as an antimicrobial peptide with enhanced activities. We used S. aureus biofilm-prevention assays to determine bacterial biomass in the presence of SPLUNC1 and SPLUNC1Δα4 recombinant proteins, or SPLUNC1-derived peptides (α4 and α4M1), using the well-established crystal-violet biofilm detection assay. The SPLUNC1Δα4 showed markedly reduced biofilm prevention compared to the parent protein. Surprisingly, the 30-residue long α4 motif alone demonstrated minimal biofilm prevention activities. However, structural optimization of the α4 motif resulted in a modified peptide (α4M1) with significantly enhanced antibiofilm properties against methicillin-sensitive (MSSA) and-resistant (MRSA) S. aureus, including six different clinical strains of MRSA and the well-known USA300. Hemolytic activity was undetectable at up to 100μM for the peptides. The data warrant further investigation of α4-derived AMPs to explore the potential application of antimicrobial peptides to combat bacterial biofilm-related infections.},
}
@article {pmid30215741,
year = {2018},
author = {Cools, F and Torfs, E and Vanhoutte, B and de Macedo, MB and Bonofiglio, L and Mollerach, M and Maes, L and Caljon, G and Delputte, P and Cappoen, D and Cos, P},
title = {Streptococcus pneumoniae galU gene mutation has a direct effect on biofilm growth, adherence and phagocytosis in vitro and pathogenicity in vivo.},
journal = {Pathogens and disease},
volume = {76},
number = {7},
pages = {},
doi = {10.1093/femspd/fty069},
pmid = {30215741},
issn = {2049-632X},
abstract = {Streptococcus pneumoniae, the most common cause of bacterial pneumonia, has developed a wide range of virulence factors to evade the immune system of which the polysaccharide capsule is the most important one. Formation of this capsule is dependent on the cps gene locus, but also involves other genes-like galU. The pyrophosphorylase encoded by galU plays a role in the UDP-glucose metabolism of prokaryotes and is required for the biosynthesis of capsular polysaccharides. In this paper, the effect of a galU mutation leading to a dysfunctional UDP-glucose pyrophosphorylase (UDPG:PP) on in vitro biofilm biomass, adherence to lung epithelial cells and macrophage phagocytosis is studied. Last, in vivo virulence using a Galleria mellonella model has been studied. We show that the mutation improves streptococcal adherence to epithelial cells and macrophage phagocytosis in vitro, while there is no definitive correlation on biofilm formation between parent and mutant strains. Moreover, in vivo virulence is attenuated for all mutated strains. Together, these results demonstrate that a galU mutation in S. pneumoniae influences host cell interactions in vitro and in vivo and can strongly influence the outcome of a streptococcal infection. As such, UDPG:PP is worth investigating further as a potential drug target.},
}
@article {pmid30215136,
year = {2018},
author = {Bisson, C and Lec, PH and Blique, M and Thilly, N and Machouart, M},
title = {Presence of trichomonads in subgingival biofilm of patients with periodontitis: preliminary results.},
journal = {Parasitology research},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00436-018-6077-2},
pmid = {30215136},
issn = {1432-1955},
abstract = {This study aims to evaluate the prevalence of trichomonads in the subgingival biofilm of patients with periodontitis. Secondarily, the trichomonad presence was related to patient characteristics and periodontal clinical parameters, in order to highlight the factor favoring the development of these protozoans. Subgingival biofilm samples were collected from at least two diseased and one healthy site in 50 patients suffering from periodontitis. Trichomonads were identified using phase contrast microscopy. All patient characteristics and periodontal clinical parameter data were then statistically analyzed. From the 50 patients examined, 195 sites were sampled, including 145 diseased ones. Trichomonads were only observed on 16 of the 145 diseased sites (11%) and none in the other 50 healthy sites. Based on these results, 20% (n = 10) of patients were positive for the presence of trichomonads from at least one of the diseased sites collected. Tooth mobility, substantial supra-gingival dental deposits, and severe clinical attachment loss were statistically associated with trichomonad presence. If the subgingival biofilm of male patients over the age of 50 seemed to be more frequently contaminated with trichomonads, this data was not statistically supported. This preliminary study indicates for the first time that in periodontitis-involved patients, trichomonads are observed in the subgingival biofilm collected from diseased sites with severe bone loss, but not from healthy teeth. Further investigations are needed to fully explore the role of this microorganism in the etiology of periodontal disease.},
}
@article {pmid30214915,
year = {2017},
author = {Wilson, C and Lukowicz, R and Merchant, S and Valquier-Flynn, H and Caballero, J and Sandoval, J and Okuom, M and Huber, C and Brooks, TD and Wilson, E and Clement, B and Wentworth, CD and Holmes, AE},
title = {Quantitative and Qualitative Assessment Methods for Biofilm Growth: A Mini-review.},
journal = {Research &amp; reviews. Journal of engineering and technology},
volume = {6},
number = {4},
pages = {},
pmid = {30214915},
issn = {2319-9873},
abstract = {Biofilms are microbial communities attached to a surface and embedded in an extracellular polymeric substance which provides for the protection, stability and nutrients of the various bacterial species indwelling. These communities can build up in a variety of different environments from industrial equipment to medical devices resulting in damage, loss of productivity and disease. They also have great potential for economic and societal benefits as bioremediation agents and renewable energy sources. The great potential benefits and threats of biofilms has encouraged researchers across disciplines to study biofilm characteristics and antibiofilm strategies resulting in chemists, physicists, material scientists, and engineers, to develop beneficial biofilm applications and prevention methods. The ultimate outcome is a wealth of knowledge and innovative technology. However, without extensive formal training in microbes and biofilm research, these scientists find a daunting array of established techniques for growing, quantifying and characterizing biofilms while trying to design experiments and develop innovative laboratory protocols. This mini-review focuses on enriching interdisciplinary efforts and understanding by overviewing a variety of quantitative and qualitative biofilm characterization methods to assist the novice researcher in assay selection. This review consists of four parts. Part 1 is a brief overview of biofilms and the unique properties that demand a highly interdisciplinary approach. Part 2 describes the classical quantification techniques including colony forming unit (CFU) counting and crystal violet staining, but also introduces some modern methods including ATP bioluminescence and quartz crystal microbalance. Part 3 focuses on the characterization of biofilm morphology and chemistry including scanning electron microscopy and spectroscopic methods. Finally, Part 4 illustrates the use of software, including ImageJ and predictive modeling platforms, for biofilm analysis. Each section highlights the most common methods, including literature references, to help novice biofilm researchers make choices which commensurate with their study goals, budget and available equipment.},
}
@article {pmid30214439,
year = {2018},
author = {Santos, AL and Johnson, DB},
title = {Design and Application of a Low pH Upflow Biofilm Sulfidogenic Bioreactor for Recovering Transition Metals From Synthetic Waste Water at a Brazilian Copper Mine.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {2051},
doi = {10.3389/fmicb.2018.02051},
pmid = {30214439},
issn = {1664-302X},
abstract = {A sulfidogenic bioreactor, operated at low pH (4-5), was set up and used to remove transition metals (copper, nickel, cobalt, and zinc) from a synthetic mine water, based on the chemistry of a moderately acidic (pH 5) drainage stream at an operating copper mine in Brazil. The module was constructed as an upflow biofilm reactor, with microorganisms immobilized on porous glass beads, and was operated continuously for 462 days, during which time the 2 L bioreactor processed >2,000 L of synthetic mine water. The initial treatment involved removing copper (the most abundant metal present) off-line in a stream of H2S-containing gas generated by the bioreactor, which caused the synthetic mine water pH to fall to 2.1. The copper-free water was then amended with glycerol (the principal electron donor), yeast extract and basal salts, and pumped directly into the bioreactor where the other three transition metals were precipitated (also as sulfides), concurrent with increased solution pH. Although some acetate was generated, most of the glycerol fed to the bioreactor was oxidized to carbon dioxide, and was coupled to the reduction of sulfate to hydrogen sulfide. No archaea or eukaryotes were detected in the bioreactor microbial community, which was dominated by acidophilic sulfate-reducing Firmicutes (Peptococcaceae strain CEB3 and Desulfosporosinus acididurans); facultatively anaerobic non-sulfidogens (Acidithiobacillus ferrooxidans and Actinobacterium strain AR3) were also found in small relative abundance. This work demonstrated how a single low pH sulfidogenic bioreactor can be used to remediate a metal-rich mine water, and to facilitate the recovery (and therefore recycling) of target metals. The system was robust, and was operated empirically by means of pH control. Comparison of costs of the main consumables (glycerol and yeast extract) and the values of the metals recovered showed a major excess of the latter, supporting the view that sulfidogenic biotechnology can have significant economic as well as environmental advantages over current approaches used to remediate mine waters which produce secondary toxic wastes and fail to recover valuable metals.},
}
@article {pmid30214437,
year = {2018},
author = {Camarillo-Márquez, O and Córdova-Alcántara, IM and Hernández-Rodríguez, CH and García-Pérez, BE and Martínez-Rivera, MA and Rodríguez-Tovar, AV},
title = {Antagonistic Interaction of Staphylococcus aureus Toward Candida glabrata During in vitro Biofilm Formation Is Caused by an Apoptotic Mechanism.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {2031},
doi = {10.3389/fmicb.2018.02031},
pmid = {30214437},
issn = {1664-302X},
abstract = {Background: Infections caused by Candida species and Staphylococcus aureus are associated with biofilm formation. C. albicans-S. aureus interactions are synergistic due to the significant increase in mixed biofilms and improved resistance to vancomycin of S. aureus. C. glabrata and S. aureus both are nosocomial pathogens that cause opportunistic infections in similar host niches. However, there is scarce information concerning the interaction between these last microorganisms. Results: The relationship between C. glabrata and S. aureus was evaluated by estimating the viability of both microorganisms in co-culture of planktonic cells and in single and mixed biofilms. An antagonistic behavior of S. aureus and their cell-free bacterial supernatant (CFBS) toward C. glabrata, both in planktonic form and in biofilms, was demonstrated. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and confocal laser scanning microscopy (CLSM) images showed yeast cells surrounded by bacteria, alterations in intracytoplasmic membranes, and non-viable blastoconidia with intact cell walls. Concomitantly, S. aureus cells remained viable and unaltered. The antagonistic activity of S. aureus toward C. glabrata was not due to cell-to-cell contact but the presence of CFBS, which causes a significant decrement in yeast viability and the formation of numerous lipid droplets (LDs), reactive oxygen species (ROS) accumulation, as well as nuclear alterations, and DNA fragmentation indicating the induction of an apoptotic mechanism. Conclusion: Our results demonstrate that the S. aureus CFBS causes cell death in C. glabrata by an apoptotic mechanism.},
}
@article {pmid30214432,
year = {2018},
author = {Guillonneau, R and Baraquet, C and Bazire, A and Molmeret, M},
title = {Multispecies Biofilm Development of Marine Bacteria Implies Complex Relationships Through Competition and Synergy and Modification of Matrix Components.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1960},
doi = {10.3389/fmicb.2018.01960},
pmid = {30214432},
issn = {1664-302X},
abstract = {Microbial communities composition is largely shaped by interspecies competition or cooperation in most environments. Ecosystems are made of various dynamic microhabitats where microbial communities interact with each other establishing metabolically interdependent relationships. Very limited information is available on multispecies biofilms and their microhabitats related to natural environments. The objective of this study is to understand how marine bacteria isolated from biofilms in the Mediterranean Sea interact and compete with each other when cultivated in multispecies biofilms. Four strains (Persicivirga mediterranea TC4, Polaribacter sp. TC5, Shewanella sp. TC10 and TC11) with different phenotypical traits and abilities to form a biofilm have been selected from a previous study. Here, the results show that these strains displayed a different capacity to form a biofilm in static versus dynamic conditions where one strain, TC11, was highly susceptible to the flux. These bacteria appeared to be specialized in the secretion of one or two exopolymers. Only TC5 seemed to secrete inhibitory molecule(s) in its supernatant, with a significant effect on TC10. Most of the strains negatively impacted each other, except TC4 and TC10, which presented a synergetic effect in the two and three species biofilms. Interestingly, these two strains produced a newly secreted compound when grown in dual-species versus mono-species biofilms. TC5, which induced a strong inhibition on two of its partners in dual-species biofilms, outfitted the other bacteria in a four-species biofilm. Therefore, understanding how bacteria respond to interspecific interactions should help comprehending the dynamics of bacterial populations in their ecological niches.},
}
@article {pmid30212901,
year = {2018},
author = {Salinas, B and Guembe, M and Cussó, L and Kestler, M and Guinea, J and Desco, M and Muñoz, P and Bouza, E},
title = {Assessment of the anti-biofilm effect of micafungin in an animal model of catheter-related candidemia.},
journal = {Medical mycology},
volume = {},
number = {},
pages = {},
doi = {10.1093/mmy/myy065},
pmid = {30212901},
issn = {1460-2709},
abstract = {In cases where catheter-related candidemia (CRC) must be managed without catheter withdrawal, antifungal lock therapy using highly active anti-biofilm (HAAB) agents is combined with systemic treatment. However, the activity of HAAB agents has never been studied in in vivo models using bioluminescence. We assessed the efficacy of micafungin using a bioluminescent Candida albicans SKCA23-ACTgLuc strain in an animal model of CRC. We divided 33 female Wistar rats into five groups: sham (A), infected nontreated (B), treated with lock therapy (0.16 mg/ml) (C), systemically treated only (1 mg/kg) (D), and systemically treated+lock (E). Catheters were colonized 24 h before insertion into the femoral vein (day 0). Treatment started on day 1 and lasted 7 days, followed by 7 days of surveillance. Bioluminescence assays were carried out on days 1, 3, 5, and 14, together with daily monitoring of clinical variables. Postmortem microbiological cultures from the catheter and several tissue samples were also obtained. Overall, 28 rats (84.8%) completed the study. Group B animals showed significant weight loss at days 2, 4, and 5 compared with groups C and D (P < .05). In group B, no animals survived after day 7, 75% had CRC, and bioluminescence remained constant 5 days after catheter implantation. Positive catheter culture rates in groups C, D, and E were, respectively, 83.3%, 62.5%, and 25.0% (P = .15). Micafungin proved to be a HAAB agent when administered both systemically and in lock therapy in an animal model of CRC, although the bioluminescence signal persists after treatment. This persistence should be further analyzed.},
}
@article {pmid30212821,
year = {2018},
author = {Zhang, JM and Liu, J and Wang, K and Zhang, X and Zhao, T and Luo, HM},
title = {Observations of Bacterial Biofilm on Ureteral Stent and Studies on the Distribution of Pathogenic Bacteria and Drug Resistance.},
journal = {Urologia internationalis},
volume = {},
number = {},
pages = {1-7},
doi = {10.1159/000490621},
pmid = {30212821},
issn = {1423-0399},
abstract = {OBJECTIVE: This study aims to observe the morphological characteristics of bacterial biofilm on the surface of ureteral stents and analyze distribution characteristics of pathogens on the bacterial biofilm and drug resistance.<br><br>METHODS: Ureteral stents were sampled from 129 patients. A scanning electron microscope was used to observe the morphological characteristics of bacterial biofilms, and the Congo red medium was applied to screen bacterial biofilm strains on the renal pelvis section, ureter section, and bladder section respectively. Urine culture was performed, and the drug sensitive test analysis was carried out for the pathogenic bacteria detected.<br><br>RESULTS: Bacterial biofilms can be observed on the surface of ureteral stents, and these bacteria are embraced by large amounts of fiber membranes. A total of 107 patients were found to be positive for biofilms with a positive rate of 82.9%. The positive rates of the bladder section, ureter section, renal pelvis section, and urine culture were 85.0, 42.9, 67.3, and 24.3% respectively. Pathogenic bacteria mainly concentrated on Escherichia coli, and the drug resistance rate of the bacterial biofilm strains on the ureteral stent was relatively higher.<br><br>CONCLUSION: The bacterial biofilm on the ureteral stent is an important factor that induces catheter-associated urinary tract infections.},
}
@article {pmid30212777,
year = {2018},
author = {Ye, Y and Huang, Y and Xia, A and Fu, Q and Liao, Q and Zeng, W and Zheng, Y and Zhu, X},
title = {Optimizing culture conditions for heterotrophic-assisted photoautotrophic biofilm growth of Chlorella vulgaris to simultaneously improve microalgae biomass and lipid productivity.},
journal = {Bioresource technology},
volume = {270},
number = {},
pages = {80-87},
doi = {10.1016/j.biortech.2018.08.116},
pmid = {30212777},
issn = {1873-2976},
abstract = {In order to solve the technical bottleneck that the biomass yield and lipid accumulation cannot be increased simultaneously during microalgae growth, a heterotrophic-assisted photoautotrophic biofilm (HAPB) growth mode of Chlorella vulgaris was constructed. The light penetration capability of the microalgae biofilm formed through heterotrophic-assisted photoautotrophic growth was 64% stronger than that formed by photoautotrophic growth. Due to the different demands of autotrophic and heterotrophic growth of microalgae, the nutrient environment and growth conditions were optimized to fully utilize the advantages and potentials of the HAPB culture model. An optimized molar ratio of total inorganic carbon (CO2) to total organic carbon (glucose) (20:1) and a molar ratio of total carbon to total nitrogen (72:1) were obtained. The maximum specific growth rate of Chlorella vulgaris increased by 78% compared to that before optimization. Meanwhile, the lipid content and yield increased by 120% and 147%, respectively, up to 47.53% and 41.95 g m-2.},
}
@article {pmid30212776,
year = {2018},
author = {Zhao, B and Ran, XC and Tian, M and An, Q and Guo, JS},
title = {Assessing the performance of a sequencing batch biofilm reactor bioaugmented with P. stutzeri strain XL-2 treating ammonium-rich wastewater.},
journal = {Bioresource technology},
volume = {270},
number = {},
pages = {70-79},
doi = {10.1016/j.biortech.2018.09.015},
pmid = {30212776},
issn = {1873-2976},
abstract = {Pseudomonas stutzeri XL-2, with the capability of heterotrophic nitrification-aerobic denitrification and biofilm-forming, was applied in a sequencing batch biofilm reactor (SBBR) for bioaugmented treatment of ammonium-rich wastewater. The bioaugmented system SBBR 1 showed a rapid development of biofilm and relatively shorter time for biofilm hanging compared with the control system SBBR 2 without strain XL-2 inoculation. At different NH4+-N loads of 100, 200 and 300 mg/L, the effluent TN removal ratios ranged in 88.7-97.0%, 85.1-93.5% and 87.8-92.5% respectively in SBBR 1, while only ranged in 77.4-85.4%, 77.1-84.3% and 79.8-85.0% in SBBR 2. Less accumulation of NO2--N and NO3--N resulted in the better performance on TN removal in SBBR 1. Microbial community structure analysis revealed that strain XL-2 successfully proliferated in SBBR 1 and contributed to the less accumulation of NO2--N and NO3--N as well as biofilm formation.},
}
@article {pmid30212684,
year = {2018},
author = {Han, F and Wei, D and Ngo, HH and Guo, W and Xu, W and Du, B and Wei, Q},
title = {Performance, microbial community and fluorescent characteristic of microbial products in a solid-phase denitrification biofilm reactor for WWTP effluent treatment.},
journal = {Journal of environmental management},
volume = {227},
number = {},
pages = {375-385},
doi = {10.1016/j.jenvman.2018.09.002},
pmid = {30212684},
issn = {1095-8630},
abstract = {Microbial products, i.e. extracellular polymeric substance (EPS) and soluble microbial product (SMP), have a significant correlation with microbial activity of biologically based systems. In present study, the spectral characteristics of two kinds of microbial products were comprehensively evaluated in a solid-phase denitrification biofilm reactor for WWTP effluent treatment by using poly (butylene succinate) (PBS) as carbon source. After the achievement of PBS-biofilm, nitrate and total nitrogen removal efficiencies were high of 97.39 ± 1.24% and 96.38 ± 1.1%, respectively. The contents of protein and polysaccharide were changed different degrees in both LB-EPS and TB-EPS. Excitation-emission matrix (EEM) implied that protein-like substances played a significant role in the formation of PBS-biofilm. High-throughput sequencing result implied that the proportion of denitrifying bacteria, including Simplicispira, Dechloromonas, Diaphorobacter, Desulfovibrio, increased to 9.2%, 7.4%, 4.8% and 3.6% in PBS-biofilm system, respectively. According to EEM-PARAFAC, two components were identified from SMP samples, including protein-like substances for component 1 and humic-like and fulvic acid-like substances for component 2, respectively. Moreover, the fluorescent scores of two components expressed significant different trends to reaction time. Gas chromatography-mass spectrometer (GC-MS) implied that some new organic matters were produced in the effluent of SP-DBR due to biopolymer degradation and denitrification processes. The results could provide a new insight about the formation and stability of solid-phase denitrification PBS-biofilm via the point of microbial products.},
}
@article {pmid30212364,
year = {2018},
author = {Ead, JK and Snyder, RJ and Wise, J and Cuffy, C and Jafary, H and Fischborn, K},
title = {Is PASH Syndrome a Biofilm Disease?: A Case Series and Review of the Literature.},
journal = {Wounds : a compendium of clinical research and practice},
volume = {30},
number = {8},
pages = {216-223},
pmid = {30212364},
issn = {1943-2704},
abstract = {INTRODUCTION: When occurring together, pyoderma gangrenosum, severe acne, and hidradenitis suppurativa have been described as PASH syndrome. Due to the chronic autoinflammatory state existing in affected patients, PASH syndrome has been attributed to the dysregulation of wound healing.<br><br>CASE REPORTS: Two cases are presented that demonstrate the paradigmatic clinical features of PASH syndrome and its potential link as an expanding spectrum of bacterial biofilm disorder.<br><br>CONCLUSIONS: As reported herein, based on biofilm's clinical presentation and resistance to proper wound healing, it could serve as the common denominator and may redirect clinicians' treatment pathways in the near future.},
}
@article {pmid30211421,
year = {2018},
author = {Dai, X and Zhao, Y and Yu, Y and Chen, X and Wei, X and Zhang, X and Li, C},
title = {All-in-one NIR-activated nanoplatforms for enhanced bacterial biofilm eradication.},
journal = {Nanoscale},
volume = {},
number = {},
pages = {},
doi = {10.1039/c8nr04748k},
pmid = {30211421},
issn = {2040-3372},
abstract = {The chronic infection of humans by antibiotic-resistant bacteria and their related biofilm have, so far, not been properly addressed. In the present work, we developed a novel antibacterial nanoplatform showing the most efficient antibiotic-resistant bacteria inhibition and biofilm eradication. This particular formulation contains tobramycin-conjugated graphene oxide, for efficiently capturing bacteria through electrostatic interactions and eliminating bacteria as a &quot;nano-knife&quot;, and copper sulphide nanoparticles for enhancing the photothermal and photodynamic properties. This novel formulation can selectively eliminate bacteria over NIH 3T3 cells, and the biofilm eradication capacity was up to 70%. Importantly, the nanoplatforms can inhibit bacterial growth and promote the repair of antibiotic-resistant bacteria-infected wounds on rats without non-specific damage to normal tissue. This work provides an effective, simple, and rapid method for the design and fabrication of near-infrared light-induced nanoplatforms that offer possibilities to treat biofilm-related infections.},
}
@article {pmid30210788,
year = {2018},
author = {Mubarak, Z and Humaira, A and Gani, BA and Muchlisin, ZA},
title = {Preliminary study on the inhibitory effect of seaweed Gracilaria verrucosa extract on biofilm formation of Candida albicans cultured from the saliva of a smoker.},
journal = {F1000Research},
volume = {7},
number = {},
pages = {684},
doi = {10.12688/f1000research.14879.1},
pmid = {30210788},
issn = {2046-1402},
abstract = {Background:Candida albicans is an opportunistic fungus that infects the oral cavity. Increases in colony numbers of C. albicans can be caused by multiple factors, such as smoking, a weakened immune system, taking antibiotics and with immune-compromised individuals. Smoking can increase the virulence factor of C. albicans and make it stronger. One of the virulence factors of C. albicans is the biofilm it forms. The C. albicans biofilm makes it more tolerant to extracts of the seaweed Gracilariaverrucosa, which has antifungal activity. The objective of the study was to examine the ability of the G.verrucosa extracts to inhibit the formation of biofilm by C. albicans obtained from the saliva of smoker. Methods: A total of six concentrations of G. verrucosa (6.25, 12.5, 25, 50, 75 and 100%) were tested in this study. The positive control was fluconazole 0.31 µg/ml C. albicans was taken from the saliva of one smoker in Faculty of Dentistry, Syiah Kuala University. The total amount of biofilm was assessed using an ELISA reader. The data were subjected to Kruskal-Wallis test at a significance limit of p<0.05. Results: The seaweed extract has three bio-active compounds: steroids, terpenoid, and tannins. The results showed that the inhibitory activity of seaweed on C. albicans biofilm formation increases as its concentration increases. The highest effectiveness was recorded at a seaweed concentration of 100% at 48 h of exposure. Conclusions: The optimal inhibition of the C. albicans biofilm formation was recorded at the concentration of 100% G. verrucosa after 48 hours of exposure.},
}
@article {pmid30210459,
year = {2018},
author = {Yang, L and Zheng, C and Chen, Y and Ying, H},
title = {FLO Genes Family and Transcription Factor MIG1 Regulate Saccharomyces cerevisiae Biofilm Formation During Immobilized Fermentation.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1860},
doi = {10.3389/fmicb.2018.01860},
pmid = {30210459},
issn = {1664-302X},
abstract = {Saccharomyces cerevisiae immobilization is commonly used for efficient ethanol fuel production in industry due to the relatively higher ethanol stress resistance of S. cerevisiae in biofilms relative to planktonic cells. The mechanisms of biofilm formation and stress resistance, however, remain ambiguous. By analyzing biofilm and planktonic cell transcriptomes, this study observed that MIG1 (encoding a transcription factor) expression in cells increases during the biofilm formation process. To identify the role of MIG1 in yeast biofilm formation and the ethanol resistance of these cells, MIG1 was deleted and complemented in S. cerevisiae 1308. Results showed the MIG1 deletion mutant strain demonstrated weaker biofilm formation ability both on fibers and plastic than the wild-type and these could be restored by expressing MIG1 in deletion mutant. To verify the ability of MIG1 to regulate the expression of FLO genes, which encode adhesions responsible for yeast biofilm formation, FLO gene transcription levels were measured via qRT-PCR. Relative to wild-type S. cerevisiae, the adhesion genes FLO1, 5, and 9 which also demonstrate increased expression in the transcriptome of yeast cells during biofilm formation, but not FLO11, were down-regulated in the MIG1 mutant strain. Additionally, the MIG1 mutant lost a majority of its flocculation ability, which depended on cell-cell adhesions and its slightly invasive growth ability, dependent on cell-substrate adhesion. Deleting FLO1, 5, and 9 decreased biofilm formation on plastics, suggesting these FLO genes contribute to the biofilm formation process alongside FLO11. Moreover, the ethanol tolerance of yeast decreased in the MIG1 deletion mutant as well as the FLO11 deletion mutant, resulting in reduced biofilm formation during fermentation. It remains possible that in the later period of fermentation, when ethanol has accumulated, an over-expression of the FLO1, 5, and 9 genes regulated by MIG1 would enhanced cell-cell adhesions and thus protect cells in the outer layer of biofilms from ethanol, a function primarily dependent on cell-cell adhesions. This work offers a possible explanation for how biofilm formation is regulated during the immobilized fermentation process, and can enhance environmental tolerance in industrial production.},
}
@article {pmid30209548,
year = {2018},
author = {Wang, Y and Wang, Y and Sun, L and Grenier, D and Yi, L},
title = {Streptococcus suis biofilm: regulation, drug-resistance mechanisms, and disinfection strategies.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-018-9356-z},
pmid = {30209548},
issn = {1432-0614},
support = {2018YFD0500100//the National Key Research and Development Program of China/ ; 31772761,31540095//the National Natural Science Foundation of China/ ; },
abstract = {Streptococcus suis (S. suis) is a major swine pathogen and an important zoonotic agent. Like most pathogens, the ability of S. suis to form biofilms plays a significant role in its virulence and drug resistance. A better understanding of the mechanisms involved in biofilm formation by S. suis as well as of the methods to efficiently remove and kill biofilm-embedded bacteria can be of high interest for the prevention and treatment of S. suis infections. The aim of this literature review is to update our current knowledge of S. suis biofilm formation, regulatory mechanisms, drug-resistance mechanisms, and disinfection strategies.},
}
@article {pmid30208852,
year = {2018},
author = {Khider, M and Willassen, NP and Hansen, H},
title = {The alternative sigma factor RpoQ regulates colony morphology, biofilm formation and motility in the fish pathogen Aliivibrio salmonicida.},
journal = {BMC microbiology},
volume = {18},
number = {1},
pages = {116},
doi = {10.1186/s12866-018-1258-9},
pmid = {30208852},
issn = {1471-2180},
abstract = {BACKGROUND: Quorum sensing (QS) is a cell-to cell communication system that bacteria use to synchronize activities as a group. LitR, the master regulator of QS in Aliivibrio salmonicida, was recently shown to regulate activities such as motility, rugosity and biofilm formation in a temperature dependent manner. LitR was also found to be a positive regulator of rpoQ. RpoQ is an alternative sigma factor belonging to the sigma -70 family. Alternative sigma factors direct gene transcription in response to environmental signals. In this work we have studied the role of RpoQ in biofilm formation, colony morphology and motility of A. salmonicida LFI1238.<br><br>RESULTS: The rpoQ gene in A. salmonicida LFI1238 was deleted using allelic exchange. We found that RpoQ is a strong repressor of rugose colony morphology and biofilm formation, and that it controls motility of the bacteria. We also show that overexpression of rpoQ in a ΔlitR mutant of A. salmonicida disrupts the biofilm produced by the ΔlitR mutant and decreases its motility, whereas rpoQ overexpression in the wild-type completely eliminates the motility.<br><br>CONCLUSION: The present work demonstrates that the RpoQ sigma factor is a novel regulatory component involved in modulating motility, colony morphology and biofilm formation in the fish pathogen A. salmonicida. The findings also confirm that RpoQ functions downstream of the QS master regulator LitR. However further studies are needed to elucidate how LitR and RpoQ work together in controlling phenotypes related to QS in A. salmonicida.},
}
@article {pmid30208544,
year = {2018},
author = {Zhang, X and Chen, T and Zhang, J and Zhang, H and Zheng, S and Chen, Z and Ma, Y},
title = {Performance of the nitrogen removal, bioactivity and microbial community responded to elevated norfloxacin antibiotic in an Anammox biofilm system.},
journal = {Chemosphere},
volume = {210},
number = {},
pages = {1185-1192},
doi = {10.1016/j.chemosphere.2018.07.100},
pmid = {30208544},
issn = {1879-1298},
abstract = {Antibiotic pollution in nitrogen contained wastewater is an urgent issue. In this study, the nitrogen removal, biofilm property and microbial community of Anammox system were investigated with elevated norfloxacin (NOR) feeding. Batch experiments were carried out to detect the specific anammox activity (SAA) in each phase. Anammox system could resist NOR in 0.001-50 mg L-1, in which the nitrogen removal was firstly limited to 0.220 from the initial 0.345 by NOR suppression and then regained to 0.354 kg m-3 d-1 after acclimatization. SAA decreased to 7.56 from the initial 10.84 and then climbed up to 11.01 mg g-1 SS, while the relative abundance of Candidatus Kuenenia decreased to 11.33% and then picked up to 25.28% from the initial 20.74%. The suppression threshold on Anammox was calculated as 50-100 mg L-1 NOR, the NRR, SAA and Candidatus Kuenenia abundance all recovered to almost the initial level when NOR feeding was terminated.},
}
@article {pmid30207891,
year = {2018},
author = {Morris, J and Kelly, N and Elliott, L and Grant, A and Wilkinson, M and Hazratwala, K and McEwen, P},
title = {Evaluation of Bacteriophage Anti-Biofilm Activity for Potential Control of Orthopedic Implant-Related Infections Caused by Staphylococcus Aureus.},
journal = {Surgical infections},
volume = {},
number = {},
pages = {},
doi = {10.1089/sur.2018.135},
pmid = {30207891},
issn = {1557-8674},
abstract = {BACKGROUND: Despite significant advancements in surgical protocols and biomaterials for orthopedics, peri-prosthetic joint infection (PJI) remains a leading cause of implant failure. Staphylococcus aureus nasal colonization is an established risk factor for PJI, with methicillin-sensitive S. aureus a leading cause of orthopedic implant-related infections. The purpose of these in vitro studies was to investigate the antibacterial activity of a tailored bacteriophage cocktail against planktonic and biofilm-associated S. aureus.<br><br>METHODS: The S. aureus strains (n = 30) were screened for their susceptibility to a library of S. aureus-specific bacteriophage (n = 31). Five bacteriophage preparations that demonstrated bactericidal activity against >90% of S. aureus strains tested were combined as a StaPhage cocktail and assessed for their antibacterial activity toward planktonic and biofilm-associated S. aureus, with biofilms established on three-dimensional-printed porous titanium scaffolds.<br><br>RESULTS: StaPhage treatment immediately after bacterial inoculation inhibited growth of S. aureus by >98% in eight hour cultures when multiplicity of infection of phages to bacteria was greater than 1:1 (p < 0.01). Viable bacterial numbers within biofilms on titanium surfaces were significantly reduced (6.8 log10 to 6.2 log10 colony forming units [CFU]; p < 0.01) after exposure to the StaPhage cocktail, in vitro. No significant reduction was observed in biofilms exposed to 100 times the minimal inhibitory concentration of cefazolin (log10 6.81 CFU).<br><br>CONCLUSIONS: Combined, these data demonstrate the in vitro efficacy of S. aureus-specific bacteriophage cocktails against S. aureus growing on porous titanium and warrant further in vivo studies in a clinically relevant animal model to evaluate the potential application of bacteriophage in the management of PJI caused by S. aureus.},
}
@article {pmid30207213,
year = {2018},
author = {Gula, G and Dorotkiewicz-Jach, A and Korzekwa, K and Valvano, MA and Drulis-Kawa, Z},
title = {Complex Signaling Networks Controlling Dynamic Molecular Changes in Pseudomonas aeruginosa Biofilm.},
journal = {Current medicinal chemistry},
volume = {},
number = {},
pages = {},
doi = {10.2174/0929867325666180912110151},
pmid = {30207213},
issn = {1875-533X},
abstract = {The environment exerts strong influence on microbes. Adaptation of microbes to changing conditions is a dynamic process regulated by complex networks. Pseudomonas aeruginosa is a life-threating, versatile opportunistic and multi drug resistant pathogen that provides a model to investigate adaptation mechanisms to environmental changes. The ability of P. aeruginosa to form biofilms and to modify virulence in response to environmental changes are coordinated by various mechanisms including two-component systems (TCS), and secondary messengers involved in quorum sensing (QS) and c-di-GMP networks (diguanylate cyclase systems, DGC). In this review, we focus on the role of c-di-GMP during biofilm formation. We describe TCS and QS signal cascades regulated by c-di-GMP in response to changes in the external environment. We present a complex signaling network dynamically changing during the transition of P. aeruginosa from the free-living to sessile mode of growth.},
}
@article {pmid30205468,
year = {2018},
author = {Silva, AF and Borges, A and Freitas, CF and Hioka, N and Mikcha, JMG and Simões, M},
title = {Antimicrobial Photodynamic Inactivation Mediated by Rose Bengal and Erythrosine Is Effective in the Control of Food-Related Bacteria in Planktonic and Biofilm States.},
journal = {Molecules (Basel, Switzerland)},
volume = {23},
number = {9},
pages = {},
doi = {10.3390/molecules23092288},
pmid = {30205468},
issn = {1420-3049},
support = {POCI-01-0145-FEDER-030219//Fundação para a Ciência e a Tecnologia/ ; },
abstract = {The thermal and chemical-based methods applied for microbial control in the food industry are not always environmentally friendly and may change the nutritional and organoleptic characteristics of the final products. Moreover, the efficacy of sanitizing agents may be reduced when microbial cells are enclosed in biofilms. The objective of this study was to investigate the effect of photodynamic inactivation, using two xanthene dyes (rose bengal and erythrosine) as photosensitizing agents and green LED as a light source, against Staphylococcus aureus, Listeria innocua, Enterococcus hirae and Escherichia coli in both planktonic and biofilm states. Both photosensitizing agents were able to control planktonic cells of all bacteria tested. The treatments altered the physicochemical properties of cells surface and also induced potassium leakage, indicating damage of cell membranes. Although higher concentrations of the photosensitizing agents (ranging from 0.01 to 50.0 μmol/L) were needed to be applied, the culturability of biofilm cells was reduced to undetectable levels. This finding was confirmed by the live/dead staining, where propidium iodide-labeled bacteria numbers reached up to 100%. The overall results demonstrated that photoinactivation by rose bengal and erythrosine may be a powerful candidate for the control of planktonic cells and biofilms in the food sector.},
}
@article {pmid30204411,
year = {2018},
author = {Perez-Soto, N and Creese, O and Fernández-Trillo, F and Krachler, AM},
title = {Aggregation of Vibrio cholerae by cationic polymers enhances quorum sensing but over-rides biofilm dissipation in response to autoinduction.},
journal = {ACS chemical biology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acschembio.8b00815},
pmid = {30204411},
issn = {1554-8937},
abstract = {Vibrio cholerae is a Gram-negative bacterium found in aquatic environments and a human pathogen of global significance. Its transition between host-associated and environmental life styles involves the tight regulation of niche-specific phenotypes such as motility, biofilm formation and virulence. V. cholerae's transition from the host to environmental dispersal usually involves suppression of virulence and dispersion of biofilm communities. In contrast to this naturally occurring transition, bacterial aggregation by cationic polymers triggers a unique response, which is to suppress virulence gene expression while also triggering biofilm formation by V. cholerae, an artificial combination of traits that is potentially very useful to bind and neutralize the pathogen from contaminated water. Here, we set out to uncover the mechanistic basis of this polymer-triggered bacterial behavior. We found that bacteria-polymer aggregates undergo rapid autoinduction and achieve quorum sensing at bacterial densities far below those required for autoinduction in the absence of polymers. We demonstrate this induction of quorum sensing is due both to a rapid formation of autoinducer gradients and local enhancement of autoinducer concentrations within bacterial clusters, as well as the stimulation of CAI-1 and AI-2 production by aggregated bacteria. We further found that polymers cause an induction of the biofilm specific regulator VpsR and the biofilm structural protein RbmA, bypassing the usual suppression of biofilm during autoinduction. Overall, this study highlights that synthetic materials can be used to cross-wire natural bacterial responses to achieve a combination of phenotypes with potentially useful applications.},
}
@article {pmid30204158,
year = {2018},
author = {Kwon, HY and Kim, JY and Lee, JY and Yam, JKH and Hultqvist, LD and Xu, W and Rybtke, M and Tolker-Nielsen, T and Kim, JJ and Kang, NY and Yang, L and Park, SJ and Givskov, M and Chang, YT},
title = {CDy14: a novel biofilm probe targeting exopolysaccharide Psl.},
journal = {Chemical communications (Cambridge, England)},
volume = {},
number = {},
pages = {},
doi = {10.1039/c8cc05544k},
pmid = {30204158},
issn = {1364-548X},
abstract = {Detection of biofilm bacteria would be an ideal method for the physicians to diagnose chronic bacterial infections directly, but there are few imaging probes available so far. Here, we report the development of a novel biofilm detecting fluorescent probe, CDy14, through an unbiased screening of a fluorescence library and elucidated its binding partner Psl, an exopolysaccharide of the biofilm.},
}
@article {pmid30203144,
year = {2018},
author = {Sabba, F and Terada, A and Wells, G and Smets, BF and Nerenberg, R},
title = {Nitrous oxide emissions from biofilm processes for wastewater treatment.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-018-9332-7},
pmid = {30203144},
issn = {1432-0614},
support = {U2R10//Water Environment Research Foundation/ ; CBET0954918//National Science Foundation/ ; 17H01893//Japan Society for the Promotion of Science/ ; 1335-00100B//Teknologi og Produktion, Det Frie Forskningsråd/ ; },
abstract = {This paper discusses the microbial basis and the latest research on nitrous oxide (N2O) emissions from biofilms processes for wastewater treatment. Conditions that generally promote N2O formation in biofilms include (1) low DO values, or spatial DO transitions from high to low within the biofilm; (2) DO fluctuations within biofilm due to varying bulk DO concentrations or varying substrate concentrations; (3) conditions with high reaction rates, which lead to greater formation of intermediates, e.g., hydroxylamine (NH2OH) and nitrite (NO2-), that promote N2O formation; and (4) electron donor limitation for denitrification. Formation of N2O directly results from the activities of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), and heterotrophic denitrifying bacteria. More research is needed on the roles of AOA, comammox, and specialized denitrifying microorganisms. In nitrifying biofilms, higher bulk ammonia (NH3) concentrations, higher nitrite (NO2-) concentrations, lower dissolved oxygen (DO), and greater biofilm thicknesses result in higher N2O emissions. In denitrifying biofilms, N2O accumulates at low levels as an intermediate and at higher levels at the oxic/anoxic transition regions of the biofilms and where COD becomes limiting. N2O formed in the outer regions can be consumed in the inner regions if COD penetrates sufficiently. In membrane-aerated biofilms, where nitrification takes place in the inner, aerobic biofilm region, the exterior anoxic biofilm can serve as a N2O sink. Reactors that include variable aeration or air scouring, such as denitrifying filters, trickling filters, or rotating biological contactors (RBCs), can form peaks of N2O emissions during or following a scouring or aeration event. N2O emissions from biofilm processes depend on the microbial composition, biofilm thickness, substrate concentrations and variability, and reactor type and operation. Given the complexity and difficulty in quantifying many of these factors, it may be difficult to accurately predict emissions for full-scale treatment plants. However, a better understanding of the mechanisms and the impacts of process configurations can help minimize N2O emission from biofilm processes for wastewater treatment.},
}
@article {pmid30202852,
year = {2018},
author = {Díaz-García, J and Marcos-Zambrano, LJ and Muñoz, P and Guinea, J and Escribano, P},
title = {Does the composition of polystyrene trays affect Candida spp. biofilm formation?.},
journal = {Medical mycology},
volume = {},
number = {},
pages = {},
doi = {10.1093/mmy/myy064},
pmid = {30202852},
issn = {1460-2709},
abstract = {The biofilm formation ability of Candida species seems to have a role in the prognosis of patients with candidemia. Biofilm formation is usually tested using 96 well flat bottom polystyrene microtiter plates, although the type of plastic used is not commonly reported. This study compares biofilm formation by Candida spp. on six types of plates from three brands (three non-tissue-treated and three tissue-treated). Thirty isolates of each of the following species were selected: C. albicans, C. parapsilosis, C. glabrata, C. tropicalis, as well as 15 isolates of C. krusei (n = 135 isolates) from patients with candidemia. Biofilm production was evaluated by measuring biomass production and metabolic activity. Our results show higher biomass production and metabolic activity of biofilms formed on non-tissue-treated plates in comparison to those formed on tissue-treated plates (P < .001). We only found significant differences in metabolic activity of biofilms formed on non-tissue-treated plates (P < .003). All comparisons including biofilm formation and metabolic activity among plates of the same brand yielded higher biofilm formation on non-treated plates compared to treated plates (P < .001). Significant difference in biomass production by C. parapsilosis was only seen when comparing between the various tissue-treated plastics (P < .03). In contrast, comparisons of different non-tissue-treated tray brands yielded significant metabolic activity differences for all species except for C. parapsilosis (P < .05). Biofilm formation and metabolic activity is significantly affected by the plastic composition of non-tissue-treated trays leading to increased biofilm formation.},
}
@article {pmid30201944,
year = {2018},
author = {Subhadra, B and Kim, DH and Woo, K and Surendran, S and Choi, CH},
title = {Control of Biofilm Formation in Healthcare: Recent Advances Exploiting Quorum-Sensing Interference Strategies and Multidrug Efflux Pump Inhibitors.},
journal = {Materials (Basel, Switzerland)},
volume = {11},
number = {9},
pages = {},
doi = {10.3390/ma11091676},
pmid = {30201944},
issn = {1996-1944},
support = {2017//Chungnam National University/ ; NRF-2014R1A61029617//National Research Foundation of Korea/ ; },
abstract = {Biofilm formation in healthcare is an issue of considerable concern, as it results in increased morbidity and mortality, imposing a significant financial burden on the healthcare system. Biofilms are highly resistant to conventional antimicrobial therapies and lead to persistent infections. Hence, there is a high demand for novel strategies other than conventional antibiotic therapies to control biofilm-based infections. There are two approaches which have been employed so far to control biofilm formation in healthcare settings: one is the development of biofilm inhibitors based on the understanding of the molecular mechanism of biofilm formation, and the other is to modify the biomaterials which are used in medical devices to prevent biofilm formation. This review will focus on the recent advances in anti-biofilm approaches by interrupting the quorum-sensing cellular communication system and the multidrug efflux pumps which play an important role in biofilm formation. Research efforts directed towards these promising strategies could eventually lead to the development of better anti-biofilm therapies than the conventional treatments.},
}
@article {pmid30201526,
year = {2018},
author = {Zhang, H and Du, R and Cao, S and Wang, S and Peng, Y},
title = {Mechanisms and characteristics of biofilm formation via novel DEAMOX system based on sequencing biofilm batch reactor.},
journal = {Journal of bioscience and bioengineering},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jbiosc.2018.07.026},
pmid = {30201526},
issn = {1347-4421},
abstract = {A denitrifying ammonium oxidation (DEAMOX) process has been regarded as an innovative process to simultaneously treat ammonia and nitrate containing wastewaters, whereas very limited research has focused on its application in biofilm system. In this research, a novel DEAMOX process was established with fixed sponge carriers in a sequencing biofilm batch reactor (SBBR). To investigate biofilm formation process and characteristics can encourage further research on DEAMOX system optimization, deteriorated performance recovery strategies and application with actual wastewater. Total nitrogen removal efficiency was maintained at 93.0 % after 240 days of operation. With biofilm growth, the protein-like extracellular polymeric substances (EPS) and tightly-bound EPS (TB-EPS) of biofilms increased from 65.6 to 46.1, to 179.6 and 142.0 mg gVSS-1, respectively, revealing that protein-like substances and TB-EPS promote biofilm formation. The mechanism of biofilm formation was discussed by analyzing the morphological development and functional bacterial activities of biofilms. Furthermore, high anammox activity was obtained in biofilms with specific NH4+N removal rates over 4.29 mgN gVSS-1h-1, which were significantly higher than in suspended sludge (2.56 mgN gVSS-1h-1). Quantitative polymerase chain reaction results showed that the abundance of anammox bacteria in biofilms increased from 1.87 % to 11.48 % with biofilm growth. These results imply that mature biofilms formed on carriers and the anammox bacteria were sufficient enriched in DEAMOX-SBBR system.},
}
@article {pmid30200829,
year = {2018},
author = {Morohoshi, T and Xie, X and Ikeda, T},
title = {N-Acylhomoserine lactone-mediated quorum sensing regulates biofilm structure in Methylobacterium populi P-1M, an isolate from a pink-pigmented household biofilm.},
journal = {Bioscience, biotechnology, and biochemistry},
volume = {},
number = {},
pages = {1-7},
doi = {10.1080/09168451.2018.1518701},
pmid = {30200829},
issn = {1347-6947},
abstract = {Numerous gram-negative bacteria have quorum-sensing systems and produce AHL as a quorum-sensing signal molecule. In this study, we demonstrated that Methylobacterium populi P-1M, an isolate from a pink-pigmented household biofilm, produced two AHLs, C14:1-HSL as a predominant product and 3OHC14-HSL as a minor product. The complete genome sequence of M. populi P-1M revealed the presence of genes that are predicted to encode an AHL synthase (mpoI) and AHL receptor (mpoR). M. populi P-1M formed a pellicle-like biofilm, which had a flat surface and was easily removable. In contrast, biofilms formed by mpoI and/or mpoR deletion mutants had a wavy surface structure and strongly adhered to the glass tube. When C14:1-HSL was added to the mpoI mutant culture, the biofilm structure resembled that of the wild-type strain. These results demonstrated that the structure and adhesion strength of M. populi P-1M biofilms are determined in part by AHL-mediated quorum sensing.<br><br>ABBREVIATIONS: AHL: N-acyl-l-homoserine lactone; C14:1-HSL: N-tetradecenoyl-l-homoserine lactone; 3OHC14-HSL: N-(3-hydroxytetradecanoyl)-l-homoserine lactone; SAM: S-adenosyl-l-methionine; ACP: acyl-acyl carrier protein; EPS: extracellular polysaccharide; DMSO: dimethyl sulfoxide.},
}
@article {pmid30200616,
year = {2018},
author = {Zhou, G and Wang, YS and Peng, H and Huang, XM and Xie, XB and Shi, QS},
title = {Role of Ttca of Citrobacter Werkmanii in Bacterial Growth, Biocides Resistance, Biofilm Formation and Swimming Motility.},
journal = {International journal of molecular sciences},
volume = {19},
number = {9},
pages = {},
doi = {10.3390/ijms19092644},
pmid = {30200616},
issn = {1422-0067},
support = {2015A030313713//Natural Science Foundation of Guangdong Province/ ; 31500036 and 31770091//National Natural Science Foundation of China/ ; },
abstract = {To screen, identify and study the genes involved in isothiazolone resistance and biofilm formation in Citrobacter werkmanii strain BF-6. A Tn5 transposon library of approximately 900 mutants of C. werkmanii strain BF-6 was generated and screened to isolate 1,2-benzisothiazolin-3-one (BIT) resistant strains. In addition, the tRNA 2-thiocytidine (32) synthetase gene (ttcA) was deleted through homologous recombination and the resulting phenotypic changes of the ΔttcA mutant were studied. A total of 3 genes were successfully identified, among which ΔttcA mutant exhibited a reduction in growth rate and swimming motility. On the other hand, an increase in biofilms formation in ΔttcA were observed but not with a significant resistance enhancement to BIT. This work, for the first time, highlights the role of ttcA gene of C. werkmanii strain BF-6 in BIT resistance and biofilm formation.},
}
@article {pmid30200345,
year = {2018},
author = {Zhu, CT and Mei, YY and Zhu, LL and Xu, Y and Sheng, S and Wang, J},
title = {Recombinant Escherichia coli BL21-pET28a-egfp Cultivated with Nanomaterials in a Modified Microchannel for Biofilm Formation.},
journal = {International journal of molecular sciences},
volume = {19},
number = {9},
pages = {},
doi = {10.3390/ijms19092590},
pmid = {30200345},
issn = {1422-0067},
support = {21676130//National Natural Science Foundation of China/ ; 16KJA530002//Key Project of University Science Research of Jiangsu Province/ ; Year 2015//Shen Lan Young scholars program of Jiangsu University of Science and Technology/ ; },
abstract = {The application of whole cells as catalytic biofilms in microchannels has attracted increasing scientific interest. However, the excessive biomass formation and structure of biofilms in a reactor limits their use. A microchannel reactor with surface modification was used to colonize recombinant Escherichia coil BL21-pET28a-egfp rapidly and accelerated growth of biofilms in the microchannel. The segmented flow system of 'air/culture medium containing nanomaterials' was firstly used to modulate the biofilms formation of recombinant E. coil; the inhibitory effects of nanomaterials on biofilm formation were investigated. The results indicated that the segmental flow mode has a significant impact on the structure and development of biofilms. Using the channels modified by silane reagent, the culture time of biofilms (30 h) was reduced by 6 h compared to unmodified channels. With the addition of graphene sheets (10 mg/L) in Luria-Bertani (LB) medium, the graphene sheets possessed a minimum inhibition rate of 3.23% against recombinant E. coil. The biofilms cultivated by the LB medium with added graphene sheets were stably formed in 20 h; the formation time was 33.33% shorter than that by LB medium without graphene. The developed method provides an efficient and simple approach for rapid preparation of catalytic biofilms in microchannel reactors.},
}
@article {pmid30200229,
year = {2018},
author = {Phukhamsakda, C and Macabeo, APG and Yuyama, KT and Hyde, KD and Stadler, M},
title = {Biofilm Inhibitory Abscisic Acid Derivatives from the Plant-Associated Dothideomycete Fungus, Roussoella sp.},
journal = {Molecules (Basel, Switzerland)},
volume = {23},
number = {9},
pages = {},
doi = {10.3390/molecules23092190},
pmid = {30200229},
issn = {1420-3049},
support = {PHD/0020/2557//Thailand Research Fund/ ; Georg Forster Grant to APGM//Alexander von Humboldt-Stiftung/ ; PPP grant to M.S. and KDH//Deutscher Akademischer Austauschdienst/ ; },
abstract = {Roussoella species are well recorded from both monocotyledons and dicotyledons. As part of a research program to discover biologically active compounds from plant-associated Dothideomycetes in Thailand, the strain Roussoella sp. (MFLUCC 17-2059), which represents an undescribed species, was isolated from Clematis subumbellata Kurz, fermented in yeast-malt medium and explored for its secondary metabolite production. Bioassay-guided fractionation of the crude extract yielded the new abscisic acid derivative, roussoellenic acid (1), along with pestabacillin B (2), a related congener, and the cyclodipeptide, cyclo(S-Pro-S-Ile) (3). The structure of 1 was determined by 2D NMR spectroscopy and HR-ESIMS data analysis. Compounds 1 and 2 showed inhibitory activity on biofilm formation by Staphylococcus aureus. The biofilm formation of S. aureus was reduced to 34% at 16 µg/mL by roussoellenic acid (1), while pestabacillin B (2) only showed 36% inhibition at 256 µg/mL. In addition, compound 1 also had weak cytotoxic effects on L929 murine fibroblasts and human KB3-1 cancer cells.},
}
@article {pmid30199274,
year = {2018},
author = {Yin, B and Zhu, L and Zhang, Y and Dong, P and Mao, Y and Liang, R and Niu, L and Luo, X},
title = {The Characterization of Biofilm Formation and Detection of Biofilm-Related Genes in Salmonella Isolated from Beef Processing Plants.},
journal = {Foodborne pathogens and disease},
volume = {},
number = {},
pages = {},
doi = {10.1089/fpd.2018.2466},
pmid = {30199274},
issn = {1556-7125},
abstract = {The biofilm formation behavior of Salmonella isolated from beef processing plants was investigated under varying temperatures (4°C, 10°C, 25°C, 37°C, and 42°C) and pH (4.5, 5.0, 5.5, 6.0, 7.0, and 8.0). The relationships between the presence of biofilm-related genes and the biofilm formation capacity were evaluated. A total of 77 Salmonella strains in 8 different serotypes were assessed: Salmonella Agona (n = 43), Salmonella Senftenberg (n = 13), Salmonella Meleagridis (n = 8), Salmonella Derby (n = 7), Salmonella Kottbus (n = 2), Salmonella Calabar (n = 2), Salmonella Kingston (n = 1), and Salmonella Typhimurium (n = 1). The results showed that all tested Salmonella strains produced biofilm at 25°C and 37°C after 3 d, and Salmonella Kingston and Salmonella Senftenberg had higher biofilm production than other strains under test conditions. Serotype, incubation temperature, pH, and their interactions had significant effects on biofilm formation for Salmonella. The strongest biofilm formation capacity of Salmonella (serovar Agona, Senftenberg, Kottbus, Calabar, Kingston, and Typhimurium) occurred at 25°C and at pH 7.0. Biofilm formation was significantly inhibited for all Salmonella strains incubated at 4°C. The detection rates of genes rpoS, fliC, wcaA, and invA were 100%, and the rates of genes csgB, csgD, csrA, sirA, adrA, gly, fimH, sdiA, ompR, sipB, sipC, luxS, and pfs exceeded 75% among all biofilm producer strains. The detection rate of igaA was significantly different between different biofilm producers. Based on the findings in this study, useful information on biofilm formation of Salmonella isolated from beef processing plants in China is provided, which could help clear the technological hurdle in delaying biofilm production to deal with risks from Salmonella biofilms in the beef industry.},
}
@article {pmid30195643,
year = {2018},
author = {Vijayakumar, K and Ramanathan, T},
title = {Antiquorum sensing and biofilm potential of 5- Hydroxymethylfurfural against Gram positive pathogens.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2018.09.008},
pmid = {30195643},
issn = {1096-1208},
abstract = {The present investigates the antiquorum sensing and biofilm inhibitory potential of 5 - hydroxymethylfurfural against Chromobacterium violaceum, Streptococcus pyogenes, Streptococcus mutans, Staphylococcus aureus and Staphylococcus epidermidis. 5HMF inhibits the quorum sensing mediated violacein pigment production by 87% at 100 μg/ml concentration. A 100 μg/ml concentration of the compound inhibits S. mutans and S. epidermidis biofilm formation by 86% and 79% whereas for S. pyogenes and S. aureus 125 μg/ml concentration inhibits biofilm formation by 83% and 82%. The Confocal images clearly indicate that 5HMF as a promising antibiofilm agent.},
}
@article {pmid30195526,
year = {2018},
author = {Zou, M and Liu, D},
title = {A systematic characterization of the distribution, biofilm-forming potential and the resistance of the biofilms to the CIP processes of the bacteria in a milk powder processing factory.},
journal = {Food research international (Ottawa, Ont.)},
volume = {113},
number = {},
pages = {316-326},
doi = {10.1016/j.foodres.2018.07.020},
pmid = {30195526},
issn = {1873-7145},
abstract = {Owing to the resistance to conventional cleaning and sanitizing agents, biofilms formed on surfaces of dairy processing equipment pose a hazard to the dairy industry. The objective of this study was to evaluate the diversity of the microflora attached to various surfaces of the processing lines of a milk powder processing factory based on 16S rRNA gene sequence analysis. The production of biofilms by the bacterial strains was evaluated on polystyrene (PS) and stainless-steel (SS) surfaces by crystal violet staining method. Especially, effects of temperatures (e.g., 37 °C and 55 °C) and growth mediums (e.g., nutrient broth, NB; tryptic soy broth, TSB) on the production of biofilms by these strains on PS surfaces were explored. Besides, the tolerance of the biofilms of the strains to CIP processes (1.5% v/v HNO3 solution or 2.0% w/v NaOH solution at 80 °C) were analyzed. Forty-five isolates from eleven interior surfaces of the facilities were identified and the distribution of strains had high species diversity, which indicated that multiple spoilage and pathogenic microorganisms remained in milk powder processing lines after CIP processes. Bacteria showed higher biofilm-forming abilities on SS compared to PS surfaces under the same condition. Moreover, effects of the incubation temperature and growth medium on biofilm formation varied between genera, species, and strains. One strain of each species with biofilm-forming abilities on SS surfaces was selected to check the resistance of their biofilms formed on SS coupons to the CIP processes. Biofilms of all of the nine strains were highly or moderately alkali and acid resistant, posing a threat to the milk powder production. These results suggested that organisms within the biofilm might withstand temperature and pH changes better than planktonic organisms. More research is needed to investigate different species isolated from different facilities of the processing lines and to improve the key controlling points in the CIP processes.},
}
@article {pmid30193534,
year = {2018},
author = {Quendera, AP and Barreto, AS and Semedo-Lemsaddek, T},
title = {Antimicrobial activity of essential oils against foodborne multidrug-resistant enterococci and aeromonads in planktonic and biofilm state.},
journal = {Food science and technology international = Ciencia y tecnologia de los alimentos internacional},
volume = {},
number = {},
pages = {1082013218799027},
doi = {10.1177/1082013218799027},
pmid = {30193534},
issn = {1532-1738},
abstract = {The selection and use of natural compounds with antimicrobial activity against foodborne pathogens is of major importance. The present study evaluated the antimicrobial activity of commercial essential oils against multidrug-resistant Enterococcus spp. and Aeromonas spp. Cymbopogon flexuosus and Thymus vulgaris essential oils presented the highest inhibitory zones against both bacterial groups (p < 0.05). Subsequent determination of the minimum inhibitory concentrations showed values between 0.47 and 1.9 mg/ml for Aeromonas spp. and from 1.9 to 15 mg/ml for Enterococcus spp. The antimicrobial effect of C. flexuosus and T. vulgaris essential oils was also assessed against biofilms. Bacteria in biofilm state were subjected to 30 min or 1 h of exposure to each essential oil and eradication ability estimated by colony counting. Both essential oils exhibited antimicrobial activity against preformed Aeromonas biofilms, but were unable to successfully eradicate biofilms produced by enterococci, in the conditions under investigation. Nonetheless, the presumptive use of essential oils in the food industry should be considered in further investigations.},
}
@article {pmid30192766,
year = {2018},
author = {Ionescu, AC and Brambilla, E and Azzola, F and Ottobelli, M and Pellegrini, G and Francetti, LA},
title = {Laser microtextured titanium implant surfaces reduce in vitro and in situ oral biofilm formation.},
journal = {PloS one},
volume = {13},
number = {9},
pages = {e0202262},
doi = {10.1371/journal.pone.0202262},
pmid = {30192766},
issn = {1932-6203},
abstract = {INTRODUCTION: Micro- or nano-topography can both provide antimicrobial properties and improve osseointegration of dental implant titanium surfaces. Laser treatment is one of the best surface microtexturing techniques. The aim of this study was to evaluate in vitro and in situ biofilm formation on a laser-treated titanium surface, comparing it with two conventional surfaces, machined and grit-blasted.<br><br>METHODS: For the in vitro experiment, an oral microcosm biofilm model was developed on the surface of titanium disks and reference human enamel using a bioreactor for 48 h. For the in situ experiment, titanium implants with laser-treated, machined and grit-blasted surfaces were mounted on intraoral trays and worn by ten volunteers for 48 h. Biofilm formation was quantitatively evaluated, and surfaces were analyzed using confocal laser scanning microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy.<br><br>RESULTS–IN VITRO STUDY: Biofilm structures with a prevalence of viable cells covered most of the machined, grit-blasted and human enamel surfaces, whereas less dense biofilm structures with non-confluent microcolonies were observed on the laser-treated titanium. Laser-treated titanium showed the lowest biofilm formation, where microorganisms colonized the edges of the laser-created pits, with very few or no biofilm formation observed inside the pits.<br><br>RESULTS–IN SITU STUDY: The biofilm formation pattern observed was similar to that in the in vitro experiment. Confocal laser scanning microscopy showed complete coverage of the implant threads, with mostly viable cells in grit-blasted and machined specimens. Unexpectedly, laser-treated specimens showed few dead microbial cells colonizing the bottom of the threads, while an intense colonization was found on the threading sides.<br><br>CONCLUSION: This data suggests that laser-created microtopography can reduce biofilm formation, with a maximum effect when the surface is blasted orthogonally by the laser beam. In this sense the orientation of the laser beam seems to be relevant for the biological interaction with biofilms.},
}
@article {pmid30190485,
year = {2018},
author = {Kim, M and Jeon, J and Kim, J},
title = {Streptococcus mutans extracellular DNA levels depend on the number of bacteria in a biofilm.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {13313},
doi = {10.1038/s41598-018-31275-y},
pmid = {30190485},
issn = {2045-2322},
abstract = {Streptococcus mutans is a component of oral plaque biofilm that accumulates on the surface of teeth. The biofilm consists of extracellular components including extracellular DNA (eDNA). This study was conducted to investigate the factors that may affect the eDNA levels of S. mutans in biofilms. For the study, S. mutans UA159 biofilms were formed for 52 h on hydroxyapatite (HA) discs in 0% (w/v) sucrose +0% glucose, 0.5% sucrose, 1% sucrose, 0.5% glucose, 1% glucose, or 0.5% sucrose +0.5% glucose. Acidogenicity of S. mutans in the biofilms was measured after biofilm formation (22 h) up to 52 h. eDNA was collected after 52 h biofilm formation and measured using DNA binding fluorescent dye, SYBR Green I. Biofilms cultured in 0.5% sucrose or glucose had more eDNA and colony forming units (CFUs) and less exopolysaccharides (EPSs) than the biofilms cultured in 1% sucrose or glucose at 52 h, respectively. The biofilms formed in 0% sucrose +0% glucose maintained pH around 7, while the biofilms grown in 0.5% sucrose had more acidogenicity than those grown in 1% sucrose, and the same pattern was shown in glucose. In conclusion, the results of this study show that the number of S. mutans in biofilms affects the concentrations of eDNA as well as the acidogenicity of S. mutans in the biofilms. In addition, the thickness of EPS is irrelevant to eDNA aggregation within biofilms.},
}
@article {pmid30189563,
year = {2018},
author = {Abtahi, SM and Petermann, M and Juppeau Flambard, A and Beaufort, S and Terrisse, F and Trotouin, T and Joannis Cassan, C and Albasi, C},
title = {Micropollutants removal in tertiary moving bed biofilm reactors (MBBRs): Contribution of the biofilm and suspended biomass.},
journal = {The Science of the total environment},
volume = {643},
number = {},
pages = {1464-1480},
doi = {10.1016/j.scitotenv.2018.06.303},
pmid = {30189563},
issn = {1879-1026},
abstract = {The performance of tertiary moving bed biofilm reactors (MBBRs) was evaluated in terms of micropollutants (MPs) removal from secondary-treated municipal wastewater. After stepwise establishment of a mature biofilm, monitored by scanning electron and confocal microscopies, abiotic and biotic removals of MPs were deeply studied. Since no MPs reduction was observed by the both photodegradation and volatilization, abiotic removal of MPs was ascribed to the sorption onto the biomass. Target MPs i.e. Naproxen, Diclofenac, 17β-Estradiol and 4n-Nonylphenol, arranged in the ascending order of hydrophobicity, abiotically declined up to 2.8%, 4%, 9.5% and 15%, respectively. MPs sorption onto the suspended biomass was found around two times more than the biofilm, in line with MPs' higher sorption kinetic constants (ksor) found for the suspended biomass. When comparing abiotic and biotic aspects, we found that biotic removal outperformed its counterpart for all compounds as Diclofenac, Naproxen, 17β-Estradiol and 4n-Nonylphenol were biodegraded by 72.8, 80.6, 84.7 and 84.4%, respectively. The effect of the changes in organic loading rates (OLRs) was investigated on the pseudo-first order degradation constants (kbiol), revealing the dominant biodegradation mechanism of co-metabolism for the removal of Diclofenac, Naproxen, and 4n-Nonylphenol, while 17β-Estradiol obeyed the biodegradation mechanism of competitive inhibition. Biotic removals and kbiol values of all MPs were also seen higher in the biofilm as compared to the suspended biomass. To draw a conclusion, a quite high removal of recalcitrant MPs is achievable in tertiary MBBRs, making them a promising technology that supports both pathways of co-metabolism and competitive inhibition, next to the abiotic attenuation of MPs.},
}
@article {pmid30189320,
year = {2018},
author = {Fteita, D and Könönen, E and Gürsoy, M and Ma, X and Sintim, HO and Gürsoy, UK},
title = {Quorum sensing molecules regulate epithelial cytokine response and biofilm-related virulence of three Prevotella species.},
journal = {Anaerobe},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.anaerobe.2018.09.001},
pmid = {30189320},
issn = {1095-8274},
abstract = {Quorum sensing (QS) signaling regulates the motility, adhesion, and biofilm formation of bacteria, and at the same time activates immune response in eukaryotic organisms. We recently demonstrated that the QS molecule, dihydroxy-2, 3-pentanedione (DPD), and its analogs significantly inhibit estradiol-regulated virulence of Prevotella aurantiaca, one of the four species in the Prevotella intermedia group. Here, we examined the combined effects of estradiol and QS signaling on 1) cytokine response of human gingival keratinocytes (HMK) against whole cell extract (WCE) of P. intermedia, Prevotella nigrescens, and Prevotella pallens, and 2) biofilm formation of these three Prevotella species. All experiments were performed in the presence or absence of estradiol, and with different QS molecules: DPD and its analogs (ethyl-DPD, butyl-DPD, and isobutyl-DPD). Concentrations of interleukin (IL)-1β, -6, and -8 were determined by the Luminex multiplex immunoassay, biofilm mass was quantitatively evaluated by measuring protein concentration via the Bradford method, and the microtopography of biofilms was assessed by scanning electron microscopy (SEM) imaging. Concentrations of IL-6 and IL-8 were elevated when HMK cells were incubated with estradiol and WCE of P. intermedia and P. nigrescens, but decreased when incubated with estradiol and WCE of P. pallens. Butyl-DPD neutralized the estradiol- and WCE-induced regulation of HMK interleukin expression and, at the same time, inhibited the biofilm formation of P. intermedia and P. nigrescens. SEM micrographs revealed a decrease in biofilm mass after application of butyl-DPD, which was most detectable among the P. intermedia ATCC 25611 and P. nigrescens ATCC 33563 and AHN 8293 strains. In conclusion, butyl-DPD analog is able to neutralize the WCE-induced epithelial cytokine response and, at the same time, to inhibit the biofilm formation of P. intermedia and P. nigrescens.},
}
@article {pmid30188855,
year = {2018},
author = {Esfahanizadeh, N and Mirmalek, SP and Bahador, A and Daneshparvar, H and Akhoundi, N and Pourhajibagher, M},
title = {Formation of biofilm on various implant abutment materials.},
journal = {General dentistry},
volume = {66},
number = {5},
pages = {39-44},
pmid = {30188855},
issn = {0363-6771},
abstract = {The characteristics of prosthetic implant components, such as the type, material, and surface roughness of abutments, can affect biofilm formation. Since an ideal abutment surface for the reduction of bacterial adhesion has yet to be found, this in vitro study aimed to quantify biofilm formation on laser-treated titanium, zirconia, and titanium surfaces. Sterile titanium, zirconia, and laser-treated titanium discs were placed in sterile 48-well plates. Biofilm formation was induced by adding sterilized, unstimulated human saliva and suspensions of Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans (Aa), and Prevotella intermedia (Pi) to the wells. Viable bacteria in the biofilm were quantified with real-time polymerase chain reaction in conjunction with propidium monoazide. The disc material, the type of bacteria, and their interactions had significant effects on the bacterial counts. On all surfaces, the Pg count was significantly higher than both the Pi and Aa counts (P = 0.0001). The highest count of periodontal pathogens was found on laser-treated surfaces. The second highest and the lowest counts were found on zirconia and titanium surfaces, respectively.},
}
@article {pmid30187780,
year = {2018},
author = {Maquera-Huacho, PM and Tonon, CC and Correia, MF and Francisconi, RS and Bordini, EAF and Marcantonio, É and Spolidorio, DMP},
title = {In vitro antibacterial and cytotoxic activities of carvacrol and terpinen-4-ol against biofilm formation on titanium implant surfaces.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-11},
doi = {10.1080/08927014.2018.1485892},
pmid = {30187780},
issn = {1029-2454},
abstract = {This study evaluated the antibacterial properties of carvacrol and terpinen-4-ol against Porphyromonas gingivalis and Fusobacterium nucleatum and its cytotoxic effects on fibroblast cells. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were examined. The minimum biofilm inhibition concentration (MBIC) was evaluated by XTT assay. Biofilm decontamination on titanium surfaces was quantified (CFU ml-1), evaluated by confocal laser scanning microscopy (CLSM) and cytotoxic activity by MTT. The MIC and MBC for carvacrol were 0.007% and 0.002% for P. gingivalis and F. nucleatum, and 0.06% for terpinen-4-ol for both microorganisms. The MBIC for carvacrol was 0.03% and 0.06% for P. gingivalis and F. nucleatum, and for terpinen-4-ol was 0.06% and 0.24%. The results indicated anti-biofilm activity using carvacrol (0.26%, 0.06%) and terpinen-4-ol (0.95%, 0.24%) and showed cytotoxic activity similar to chlorohexidine (CHX). However, terpinen-4-ol (0.24%) showed higher cell viability than other treatments. Carvacrol and terpinen-4-ol showed antibacterial activity in respect of reducing biofilms. Moreover, CHX-like cytotoxicity was observed.},
}
@article {pmid30187586,
year = {2018},
author = {Calvillo-Medina, RP and Martínez Neria, M and Mena-Portales, J and Barba-Escoto, L and Raymundo, T and Campos-Guillén, J and Jones, GH and Reyes-Grajeda, JP and González-Y-Merchand, JA and Bautista-de Lucio, VM},
title = {Identification and biofilm development by a new fungal keratitis etiologic agent.},
journal = {Mycoses},
volume = {},
number = {},
pages = {},
doi = {10.1111/myc.12849},
pmid = {30187586},
issn = {1439-0507},
abstract = {BACKGROUND: In recent years, human keratitis caused by fungal plant pathogens has become more common. Biofilm is a structure that confers adaptations and virulence to fungi in keratitis. Neoscytalidium spp. are phytopathogenic and recently have been recognized as a human pathogen, using biofilm formation as a virulence factor.<br><br>OBJECTIVES: The aim of this study was isolation, identification (at the species level) and characterization of a new fungal keratitis agent.<br><br>PATIENTS/METHODS: The fungus was isolated from a 67-year-old male patient with a corneal ulcer. Biofilm formation and structure were evaluated by colorimetric methods and microscopy. To identify the fungus, morphological characteristics were examined and a phylogenetic analysis was performed.<br><br>RESULTS AND CONCLUSIONS: We report the identification of a fungus, a member of the genus Neoscytalidium which is associated with human keratitis. Phylogenetic analysis and morphological observations on conidiogenous cells, which occur only in arthric chains in aerial mycelium and the coelomycetous synasexual morph is absent identified a new species, Neoscytalidium oculus sp. nov. The fungus formed biofilm at a concentration of 1 x 106 conidia/ml, during 96h of incubation at 37°C, and also manifested hemolysis and melanin production. This is the first report in Latin America of a new species of Neoscytalidium from a clinical isolate has been identified. This article is protected by copyright. All rights reserved.},
}
@article {pmid30186266,
year = {2018},
author = {Zhang, Y and Sass, A and Van Acker, H and Wille, J and Verhasselt, B and Van Nieuwerburgh, F and Kaever, V and Crabbé, A and Coenye, T},
title = {Coumarin Reduces Virulence and Biofilm Formation in Pseudomonas aeruginosa by Affecting Quorum Sensing, Type III Secretion and C-di-GMP Levels.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1952},
doi = {10.3389/fmicb.2018.01952},
pmid = {30186266},
issn = {1664-302X},
abstract = {As one of the major pathogens in wound infections, Pseudomonas aeruginosa produces several virulence factors and forms biofilms; these processes are under the regulation of various quorum sensing (QS) systems. Therefore, QS has been regarded as a promising target to treat P. aeruginosa infections. In the present study, we evaluated the effect of the plant-derived QS inhibitor coumarin on P. aeruginosa biofilms and virulence. Coumarin inhibited QS in the P. aeruginosa QSIS2 biosensor strain, reduced protease and pyocyanin production, and inhibited biofilm formation in microtiter plates in different P. aeruginosa strains. The effects of coumarin in inhibiting biofilm formation in an in vitro wound model and reducing P. aeruginosa virulence in the Lucilia sericata infection model were strain-dependent. Transcriptome analysis revealed that several key genes involved in the las, rhl, Pseudomonas quinolone signal (PQS), and integrated QS (IQS) systems were downregulated in coumarin-treated biofilms of P. aeruginosa PAO1. Coumarin also changed the expression of genes related to type III secretion and cyclic diguanylate (c-di-GMP) metabolism. The cellular c-di-GMP level of P. aeruginosa PAO1 and recent clinical P. aeruginosa strains was significantly reduced by coumarin. These results provide new evidence for the possible application of coumarin as an anti-biofilm and anti-virulence agent against P. aeruginosa in wound infections.},
}
@article {pmid30186249,
year = {2018},
author = {Knight, DB and Rudin, SD and Bonomo, RA and Rather, PN},
title = {Acinetobacter nosocomialis: Defining the Role of Efflux Pumps in Resistance to Antimicrobial Therapy, Surface Motility, and Biofilm Formation.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1902},
doi = {10.3389/fmicb.2018.01902},
pmid = {30186249},
issn = {1664-302X},
abstract = {Acinetobacter nosocomialis is a member of the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex. Increasingly, reports are emerging of the pathogenic profile and multidrug resistance (MDR) phenotype of this species. To define novel therapies to overcome resistance, we queried the role of the major efflux pumps in A. nosocomialis strain M2 on antimicrobial susceptibility profiles. A. nosocomialis strains with the following mutations were engineered by allelic replacement; ΔadeB, ΔadeJ, and ΔadeB/adeJ. In these isogenic strains, we show that the ΔadeJ mutation increased susceptibility to beta-lactams, beta-lactam/beta-lactamase inhibitors, chloramphenicol, monobactam, tigecycline, and trimethoprim. The ΔadeB mutation had a minor effect on resistance to certain beta-lactams, rifampicin and tigecycline. In addition, the ΔadeJ mutation resulted in a significant decrease in surface motility and a minor decrease in biofilm formation. Our results indicate that the efflux pump, AdeIJK, has additional roles outside of antibiotic resistance in A. nosocomialis.},
}
@article {pmid30185388,
year = {2018},
author = {Igumnova, EM and Mishchenko, E and Haug, T and Blencke, HM and Sollid, JUE and Fredheim, EGA and Lauksund, S and Stensvåg, K and Strøm, MB},
title = {Amphipathic sulfonamidobenzamides mimicking small antimicrobial marine natural products; investigation of antibacterial and anti-biofilm activity against antibiotic resistant clinical isolates.},
journal = {Bioorganic &amp; medicinal chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.bmc.2018.08.032},
pmid = {30185388},
issn = {1464-3391},
abstract = {There is an urgent need for novel antimicrobial agents to address the threat of bacterial resistance to modern society. We have used a structural motif found in antimicrobial marine hit compounds as a basis for synthesizing a library of antimicrobial sulfonamidobenzamide lead compounds. Potent in vitro antimicrobial activity against clinically relevant bacterial strains was demonstrated for two compounds, G6 and J18, with minimal inhibitory concentrations (MIC) of 4-16 μg/ml against clinical methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE). The two compounds G6 and J18, together with several other compounds of this library, also caused ≥90% eradication of pre-established biofilm of methicillin-resistant S. epidermidis (MRSE) at 40 μg/ml. Using a luciferase assay, the mechanism of action of G6 was shown to resemble the biocide chlorhexidine by targeting the bacterial cell membrane.},
}
@article {pmid30185068,
year = {2018},
author = {Pezzoni, M and Pizarro, RA and Costa, CS},
title = {Exposure to low doses of UVA increases biofilm formation in Pseudomonas aeruginosa.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-12},
doi = {10.1080/08927014.2018.1480758},
pmid = {30185068},
issn = {1029-2454},
abstract = {The establishment of bacterial biofilms on abiotic surfaces is a complex process regulated by multiple genetic regulators and environmental factors which are able to modulate the passage of planktonic cells to a sessile state. Solar ultraviolet-A radiation (UVA, 315-400) is one of the main environmental stress factors that bacteria must face at the Earth´s surface. The deleterious effects of UVA are mainly due to oxidative damage. This paper reports that exposure to low UVA doses promotes biofilm formation in three prototypical strains of Pseudomonas aeruginosa, a relevant opportunistic human pathogen. It demonstrates that exposure of planktonic cells to sublethal doses of UVA can increase cell surface hydrophobicity and swimming motility, two parameters known to favor cell adhesion. These results suggest that UVA radiation acts, at least in part, by promoting the first stages of biofilm development.},
}
@article {pmid30184789,
year = {2018},
author = {Alvarado-Gomez, E and Martínez-Castañon, G and Sanchez-Sanchez, R and Ganem-Rondero, A and Yacaman, MJ and Martinez-Gutierrez, F},
title = {Evaluation of anti-biofilm and cytotoxic effect of a gel formulation with Pluronic F-127 and silver nanoparticles as a potential treatment for skin wounds.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {92},
number = {},
pages = {621-630},
doi = {10.1016/j.msec.2018.07.023},
pmid = {30184789},
issn = {1873-0191},
abstract = {The skin wounds cause serious burden to healthcare systems. The lack of sterility of the innate barrier function of the skin facilitates the development of microbial communities within the wound environment especially in biofilm form. Since biofilm is difficult to eradicate, new treatments have been established, such as silver nanoparticles (AgNPs), which antimicrobial and anti-biofilm properties have been studied, nevertheless, their toxic effects are known too. Different concentrations of AgNPs stabilized with a biocompatible and thermo-reversible vehicle as hydrogel Pluronic F-127 were synthesized, those formulations presented interesting thermo-reversibility which could be used to apply on wounds. The formulations (Gel 62.5, 125, and 250 ppm of AgNPs) proposed in this study showed in vitro a total inhibition of clinical strains (Staphylococcus aureus and Pseudomonas aeruginosa) in planktonic form, as well as, anti-biofilm activity was archived with the formulation of Gel 250 ppm, a total inhibition of biofilm formation with mixed culture was registered in the first 30 min of biofilm growth; even more, the viability of human fibroblasts with all gels formulations was >95%, in contrast to silver sulfadiazine cream 1% which showed the highest cytotoxic effect. PF-127 gel with AgNPs could be a prophylactic treatment for skin wounds, because its activity in critical steps on biofilm formation.},
}
@article {pmid30183351,
year = {2018},
author = {Kim, HJ and Oh, T and Baek, SY},
title = {Multidrug Resistance, Biofilm Formation, and Virulence of Escherichia coli Isolates from Commercial Meat and Vegetable Products.},
journal = {Foodborne pathogens and disease},
volume = {},
number = {},
pages = {},
doi = {10.1089/fpd.2018.2448},
pmid = {30183351},
issn = {1556-7125},
abstract = {Escherichia coli is an important food safety and public health concern because of its pathogenicity and potential for antimicrobial resistance. E. coli isolates as food contaminants and their antimicrobial resistance, biofilm-forming ability, and virulence genes were analyzed to identify the potential of E. coli in food as a major transmission route for antimicrobial resistance and infectious agents. Among the 709 samples of minced meat and fresh vegetable products tested, 18.6% were positive for E. coli. One hundred nine (29.2%) out of 383 E. coli isolates were resistant to 1 or more of the 25 tested antimicrobials. Among the isolates from minced pork, the highest rate of resistance was observed for tetracycline (52.8%), followed by ampicillin (41.6%). The highest resistance rates against tetracycline were coincident with the high amount of tetracycline sold for veterinary use. Because penicillin is the most frequently used antimicrobial in humans, with 4.52 defined daily doses per 1000 people per day, the high rate of resistance to ampicillin (41.6%) supported the potential risk of E. coli food contaminants. However, only 1.3% of the isolates possessed the virulence genes commonly involved in foodborne outbreaks of E. coli. Sixty-seven isolates (17.5%) were multidrug-resistant (MDR), and the highest MDR was observed against 14 antimicrobials. Most of the MDR E. coli isolates showed biofilm-forming ability. Therefore, these isolates will have additional protection from environmental stresses, including antimicrobials. Given the importance of E. coli to food safety and public health, our results on the prevalence of antimicrobial resistance and virulence factors provide useful information for risk management options to protect public health.},
}
@article {pmid30181476,
year = {2018},
author = {D'Abrosca, G and Paladino, A and Cuoco, E and Marasco, R and Pacifico, S and Piccolella, S and Vastano, V and Sacco, M and Isernia, C and Muscariello, L and Malgieri, G},
title = {Structural Characterization of the Lactobacillus Plantarum FlmC Protein Involved in Biofilm Formation.},
journal = {Molecules (Basel, Switzerland)},
volume = {23},
number = {9},
pages = {},
doi = {10.3390/molecules23092252},
pmid = {30181476},
issn = {1420-3049},
support = {PRIN 20157WZM8A//Ministero dell'Istruzione, dell'Università e della Ricerca/ ; },
abstract = {Lactobacillus plantarum is one of the most predominant species in the human gut microbiota of healthy individuals. We have previously characterized some probiotic features of L. plantarum LM3, as the high resistance to different stress, the binding ability toward some extracellular matrix proteins and plasminogen and the immunomodulatory role of the surface expressed adhesin EnoA1. We have also identified the flmA, flmB and flmC genes, coding for putative proteins named FlmA, FlmB and FlmC, whose null mutations partially impaired biofilm development; the L. plantarum LM3⁻6 strain, carrying a deletion in flmC, showed a high rate of autolysis, supporting the hypothesis that FlmC might be involved in cell wall integrity. Here, we report the in-silico characterization of ΔTM-FlmC, a portion of the FlmC protein. The protein has been also expressed, purified and characterized by means of CD spectroscopy, ICP-mass and UHPLC-HRMS. The obtained experimental data validated the predicted model unveiling also the presence of a bound lipid molecule and of a Mg(II) ion. Overall, we provide strong evidences that ΔTM-FlmC belongs to the LytR-CpsA-Psr (LCP) family of domains and is involved in cell envelope biogenesis.},
}
@article {pmid30181372,
year = {2018},
author = {Ge, X and Cai, Y and Chen, Z and Gao, S and Geng, X and Li, Y and Li, Y and Jia, J and Sun, Y},
title = {Bifunctional enzyme SpoT is involved in biofilm formation of Helicobacter pylori with multidrug resistance by upregulating efflux pump Hp1174 (gluP).},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.00957-18},
pmid = {30181372},
issn = {1098-6596},
abstract = {The drug resistance of Helicobacter pylori (H. pylori) is gradually becoming a serious problem. Biofilm formation is an important factor that leads to multidrug resistance in bacteria. The ability of H. pylori to form biofilms on the gastric mucosa is known. However, there are few studies on the regulatory mechanisms of H. pylori biofilm formation and multidrug resistance. Guanosine 3'-diphosphate 5'-triphosphate and guanosine 3',5'-bispyrophosphate [(p)ppGpp] are global regulatory factors and are synthesized in H. pylori by the bifunctional enzyme SpoT. It has been reported that (p)ppGpp is involved in the biofilm formation and multidrug resistance of various bacteria. In this study, we found that SpoT also plays an important role in H. pylori biofilm formation and multidrug resistance. Therefore, it is necessary to carry out some further studies regarding its regulatory mechanism. Considering that efflux pumps are of great importance in the biofilm formation and multidrug resistance of bacteria, we tried to determine whether efflux pumps controlled by SpoT participate in these activities. We found that Hp1174 (glucose/galactose transporter, gluP), an efflux pump of the major facilitator superfamily (MFS), is highly expressed in biofilm-forming and multidrug-resistant (MDR) H. pylori and is upregulated by SpoT. Through further research, we determined that gluP involved in H. pylori biofilm formation and multidrug resistance. Furthermore, the average expression level of gluP in the clinical MDR strains (C-MDR) was considerably higher than that in the clinical drug-sensitive strains (C-DSS). Taken together, our results revealed a novel molecular mechanism of H. pylori resistance to multidrug exposure.},
}
@article {pmid30181249,
year = {2018},
author = {Kampf, J and Gerwig, J and Kruse, K and Cleverley, R and Dormeyer, M and Grünberger, A and Kohlheyer, D and Commichau, FM and Lewis, RJ and Stülke, J},
title = {Selective Pressure for Biofilm Formation in Bacillus subtilis: Differential Effect of Mutations in the Master Regulator SinR on Bistability.},
journal = {mBio},
volume = {9},
number = {5},
pages = {},
doi = {10.1128/mBio.01464-18},
pmid = {30181249},
issn = {2150-7511},
abstract = {Biofilm formation by Bacillus subtilis requires the expression of genes encoding enzymes for extracellular polysaccharide synthesis and for an amyloid-like protein. The master regulator SinR represses all the corresponding genes, and repression of these key biofilm genes is lifted when SinR interacts with its cognate antagonist proteins. The YmdB phosphodiesterase is a recently discovered factor that is involved in the control of SinR activity: cells lacking YmdB exhibit hyperactive SinR and are unable to relieve the repression of the biofilm genes. In this study, we have examined the dynamics of gene expression patterns in wild-type and ymdB mutant cells by microfluidic analysis coupled to time-lapse microscopy. Our results confirm the bistable expression pattern for motility and biofilm genes in the wild-type strain and the loss of biofilm gene expression in the mutant. Moreover, we demonstrated dynamic behavior in subpopulations of the wild-type strain that is characterized by switches in sets of the expressed genes. In order to gain further insights into the role of YmdB, we isolated a set of spontaneous suppressor mutants derived from ymdB mutants that had regained the ability to form complex colonies and biofilms. Interestingly, all of the mutations affected SinR. In some mutants, large genomic regions encompassing sinR were deleted, whereas others had alleles encoding SinR variants. Functional and biochemical studies with these SinR variants revealed how these proteins allowed biofilm gene expression in the ymdB mutant strains.IMPORTANCE Many bacteria are able to choose between two mutually exclusive lifestyles: biofilm formation and motility. In the model bacterium Bacillus subtilis, this choice is made by each individual cell rather than at the population level. The transcriptional repressor SinR is the master regulator in this decision-making process. The regulation of SinR activity involves complex control of its own expression and of its interaction with antagonist proteins. We show that the YmdB phosphodiesterase is required to allow the expression of SinR-repressed genes in a subpopulation of cells and that such subpopulations can switch between different SinR activity states. Suppressor analyses revealed that ymdB mutants readily acquire mutations affecting SinR, thus restoring biofilm formation. These findings suggest that B. subtilis cells experience selective pressure to form the extracellular matrix that is characteristic of biofilms and that YmdB is required for the homeostasis of SinR and/or its antagonists.},
}
@article {pmid30180328,
year = {2018},
author = {Alizadeh, S and Ghoshal, S and Comeau, Y},
title = {Fate and inhibitory effect of silver nanoparticles in high rate moving bed biofilm reactors.},
journal = {The Science of the total environment},
volume = {647},
number = {},
pages = {1199-1210},
doi = {10.1016/j.scitotenv.2018.08.073},
pmid = {30180328},
issn = {1879-1026},
abstract = {Municipal water resource recovery facilities are the primary recipients of a significant fraction of discharged silver nanoparticle (AgNP)-containing wastes, yet the fate and potential risks of AgNPs in attached-growth biological wastewater treatment processes are poorly understood. The fate and inhibitory effects of polyvinylpyrrolidone (PVP)-coated AgNPs at environmentally-relevant nominal concentrations (10, 100, 600 μg/L) were investigated, for the first time, in high rate moving bed biofilm reactors (MBBRs) for soluble organic matter removal. The behavior and removal of continuously added AgNPs were characterized using single-particle inductively coupled plasma mass spectrometry (spICP-MS). While no inhibitory effect at average influent concentration of 10.8 μg/L Ag was observed, soluble COD removal efficiency was significantly decreased at 131 μg/L Ag in 18 days and 631 μg/L Ag in 5 days with suppressed biofilm viability. The inhibitory effect of AgNPs on treatment efficiency was highly correlated to the retained mass of total Ag in attached biofilm on the carriers. Biofilm demonstrated limited retention capacity for AgNPs over 18 days. Considerable mass of Ag (38% to 75%) was released via effluent, predominantly as NPs. We detected some chemically transformed and potentially less toxic forms of silver nanoparticles (Ag2S, AgCl), over the exposure period. This study demonstrated the distinct interaction dynamics, bioavailability and inhibitory effects of AgNPs in a biofilm system. Release of bioavailable AgNPs via effluent and AgNP-rich biofilm, sloughing off the carriers, can affect the treatment chain efficiency of downstream processes. Thus, the inhibitory effects of AgNPs can be a concern even at concentrations as low as 100 to 600 μg/L Ag in biological attached growth wastewater treatments.},
}
@article {pmid30179841,
year = {2018},
author = {Ni, H and Zhou, X and Zhang, X and Xiao, X and Liu, JF and Huan, H and Luo, Z and Wu, Z},
title = {Feasibility of using basalt fiber as biofilm Carrier to construct bio-nest for wastewater treatment.},
journal = {Chemosphere},
volume = {212},
number = {},
pages = {768-776},
doi = {10.1016/j.chemosphere.2018.08.136},
pmid = {30179841},
issn = {1879-1298},
abstract = {Generally, biofilms developed for wastewater treatment readily detach from carrier medium once available thickness exceeds about 2 mm. Carrier media made of basalt fibers (BFs) could form ball-like aggregates (more than 10 cm in size, and called bio-nest). To demonstrate its feasibility for wastewater treatment, both reactors with and without BF carriers (RBF and RCO) were evaluated in terms of nutrient removal, oxygen mass transport and biological viabilities as well as biofilm adsorption characteristics. Therefore, oxygen microprofiles and confocal images for bio-nest as well as functional groups for biofilm-attached BF were performed on microsensor systems, confocal laser scanning microscopy (CLSM) and Fourier transform infrared (FTIR). Despite COD:N ratio, both reactors removed about 90% of COD, while only RBF reactor achieved high denitrification capabilities, with nitrogen removal efficiencies varying between 60.10 ± 0.45% and 82.07 ± 0.64%. Microprofile and confocal images showed that dissolved oxygen could reach the core with depth up to 50 mm, at which viable bacteria were detected. Characteristic peaks on FT-IR spectrum demonstrated that various functional groups of polysaccharide and proteins in EPS played a key role in aggregating biofilm-attached BFs into a bio-nest. Thus, BF provides a promising alternative to conventional carrier medium for wastewater treatment.},
}
@article {pmid30179497,
year = {2018},
author = {Li, B and Qiu, Y and Zhang, J and Huang, X and Shi, HC and Yin, H},
title = {Real-time study of rapid spread of antibiotic resistance plasmid in biofilm using microfluidics.},
journal = {Environmental science &amp; technology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.est.8b03281},
pmid = {30179497},
issn = {1520-5851},
abstract = {Gene transfer in biofilms is known to play an important role in antibiotic resistance dissemination. However, the process remains poorly understood. In this study, microfluidics with time-lapse imaging was used for real-time monitoring of plasmid-mediated horizontal gene transfer (HGT) in biofilms. Pseudomonas putida KT2440 harbouring an antibiotic resistance plasmid RP4 was chosen as the donor while Escherichia coli and activated sludge bacteria were used as the recipient cells. Dynamic features of the transfer process, including the transfer rate, cell growth rate and kinetic changes of the transfer frequency, were determined. It was found that the routes for gene transfer strongly depend on the structure and composition of a biofilm. While intra-species HGT is essential to initiate a transfer event, the secondary re-transfer from transconjugants to the same species is more efficient and can cause cascading gene spread in single-strain biofilms. For the activated sludge biofilm, only small and scattered colonies formed and vertical gene transfer appears to be the dominant route after initial intra-species transfer. Furthermore, more than 46% of genera in the activated sludge were permissive to plasmid RP4, many of which are associated with human pathogens. These phenomena imply early prevention and interruptions to biofilm structure could provide an effect way to inhibit rapid antibiotic resistance gene spread and reduce the likelihood of catastrophic events associated with antibiotic resistance.},
}
@article {pmid30177917,
year = {2018},
author = {Zhang, Y and Xu, D and Shi, L and Cai, R and Li, C and Yan, H},
title = {Association Between agr Type, Virulence Factors, Biofilm Formation and Antibiotic Resistance of Staphylococcus aureus Isolates From Pork Production.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1876},
doi = {10.3389/fmicb.2018.01876},
pmid = {30177917},
issn = {1664-302X},
abstract = {Livestock-associated Staphylococcus aureus colonization and/or infections exist in pigs and people in frequent contact with pigs. In this study, a total of 130 S. aureus isolates obtained from different stages of pork production were subjected to antimicrobial susceptibility, biofilm formation, as well as PCR screening to identify virulence genes, and the accessory gene regulator alleles (agr). Among all 130 S. aureus isolates, 109 (83.8%, 109/130) isolates were positive for agr. All swine farms isolates belonged to agr IV, whereas S. aureus isolated from slaughterhouse and retail indicated diverse agr types. All isolates exhibited biofilm formation ability, and raw meat isolates (belonging to agr I) exhibited a greater ability to form strong biofilms than swine farms isolates (belonging to agr IV). agr-positive isolates were associated with more virulence genes than agr-negative isolates. Most biofilm-producing isolates were positive for microbial surface component recognizing adhesive matrix molecule (MSCRAMM), capsule type and ica group genes. The results illustrate a significant association between the prevalence rate of MSCRAMM, capsule type and ica group genes among isolates producing weak, moderate and strong biofilms. The high prevalence of resistance to ciprofloxacin, gentamicin, tetracycline, clarithromycin, clindamycin, and trimethoprim-sulfamethoxazole were mainly observed in moderate and weak biofilm producers. Our findings indicate that S. aureus isolates from pork production displayed diverse molecular ecology.},
}
@article {pmid30177768,
year = {2018},
author = {Zhang, J and Poh, CL},
title = {Regulating exopolysaccharide gene wcaF allows control of Escherichia coli biofilm formation.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {13127},
doi = {10.1038/s41598-018-31161-7},
pmid = {30177768},
issn = {2045-2322},
abstract = {While biofilms are known to cause problems in many areas of human health and the industry, biofilms are important in a number of engineering applications including wastewater management, bioremediation, and bioproduction of valuable chemicals. However, excessive biofilm growth remains a key challenge in the use of biofilms in these applications. As certain amount of biofilm growth is required for efficient use of biofilms, the ability to control and maintain biofilms at desired thickness is vital. To this end, we developed synthetic gene circuits to control E. coli MG1655 biofilm formation by using CRISPRi/dCas9 to regulate a gene (wcaF) involved in the synthesis of colanic acid (CA), a key polysaccharide in E. coli biofilm extracellular polymeric substance (EPS). We showed that the biofilm formation was inhibited when wcaF was repressed and the biofilms could be maintained at a different thickness over a period of time. We also demonstrated that it is also possible to control the biofilm thickness spatially by inhibiting wcaF gene using a genetic light switch. The results demonstrate that the approach has great potential as a new means to control and maintain biofilm thickness in biofilm related applications.},
}
@article {pmid30177175,
year = {2018},
author = {Tan, Y and Ma, S and Leonhard, M and Moser, D and Haselmann, GM and Wang, J and Eder, D and Schneider-Stickler, B},
title = {Enhancing antibiofilm activity with functional chitosan nanoparticles targeting biofilm cells and biofilm matrix.},
journal = {Carbohydrate polymers},
volume = {200},
number = {},
pages = {35-42},
doi = {10.1016/j.carbpol.2018.07.072},
pmid = {30177175},
issn = {1879-1344},
abstract = {Bacterial biofilms play a key role during infections, which are associated with an increased morbidity and mortality. The classical antibiotic therapy cannot eradicate biofilm-related infections because biofilm bacteria display high drug resistance due to biofilm matrix. Thus, novel drug delivery to overcome biofilm resistance and eliminate biofilm-protected bacteria is needed to be developed. In this study, positively charged chitosan nanoparticles (CSNP) loaded with oxacillin (Oxa) and Deoxyribonuclease I (CSNP-DNase-Oxa) were fabricated. The antibiofilm activity was evaluated against Staphylococcus aureus biofilms. Biofilm architecture on silicone surfaces was investigated by scanning electron microscopy (SEM). Confocal laser scanning microscopy (CLSM) was used to examine live/dead organisms within biofilm. CSNP-DNase-Oxa exhibited higher antibiofilm activity than Oxa-loaded nanoparticles without DNase (CSNP-Oxa) and free Oxa (Oxa and Oxa + DNase) at each concentration in all in-vitro tests. CSNP-DNase-Oxa inhibited biofilm formation in-vitro and eradicated mature biofilm effectively. CSNP-DNase-Oxa could disrupt the biofilm formation through degradation of eDNA, reduced biofilm thickness and the amount of viable cells on silicone. Repeated treatment with CSNP-DNase-Oxa for two days resulted in 98.4% biofilm reduction. Moreover, CSNP-DNase-Oxa was not only able to affect the biofilm of a standard S. aureus strain, but also showed the highest eradication of biofilms of clinical isolates compared with control groups. These results suggest the potential applicability of NPs for the treatment of biofilm-related infections and provide a platform for designing novel drug delivery with more functions.},
}
@article {pmid30175689,
year = {2018},
author = {Sun, G and Wan, J and Sun, Y and Xie, Y and Ren, S and Wang, Y},
title = {Enhanced biodegradation of pyridine using sequencing batch biofilm reactor under intermittent micro-aerobic condition.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-28},
doi = {10.1080/09593330.2018.1518995},
pmid = {30175689},
issn = {0959-3330},
abstract = {A sequencing batch biofilm reactor (SBBR) under intermittent micro-aerobic or anaerobic conditions was investigated to remove pyridine at various concentrations from synthetic wastewater. The results showed that over 98% of pyridine (influent concentration ≤ 200 mg L-1) was degraded under intermittent micro-aerobic condition, while about 21% of pyridine was removed under anaerobic condition. Additionally, at least 60% of nitrogen located in the pyridine ring was transformed to ammonium. At the same time, the sulfate reduction was obviously inhibited under intermittent micro-aerobic conditions. The microscopic observation showed that abundant microorganisms were attached on the surface or inside of porous biocarriers under intermittent micro-aerobic conditions after a short-term period of operation. High-throughput sequencing analysis demonstrated that Azotobacter, Rhodobacteraceae and Tolumonas were the dominant species in the intermittent micro-aerobic system. The kinetic study at steady period showed that pyridine degradation was fitted well with the pseudo first-order model (R2 ＞ 0.96). The two possible intermediate products were identified and the possible biodegradation pathway of pyridine was proposed under micro-aerobic condition.},
}
@article {pmid30174556,
year = {2018},
author = {Zhang, Y and Zhang, H and Zhang, Z and Wang, Y and Marhaba, T and Li, J and Sun, C and Zhang, W},
title = {Autohydrogenotrophic Denitrification Using the Membrane Biofilm Reactor for Removing Nitrate from High Sulfate Concentration of Water.},
journal = {Archaea (Vancouver, B.C.)},
volume = {2018},
number = {},
pages = {9719580},
doi = {10.1155/2018/9719580},
pmid = {30174556},
issn = {1472-3654},
abstract = {This study investigated the performance of an autohydrogenotrophic membrane biofilm reactor (MBfR) to remove nitrate from water with high sulfate concentrations. The results of simulated running showed that TN removal could be over than 98.8% with the maximum denitrification rate of 134.6 g N/m3 d under the conditions of the influent sulfate concentrations of 300 mg SO42-/l. The distribution ratio of H2 electron donor for nitrate and sulfate was 70.0 : 26.9 at the high influent loading ratio of sulfate/nitrate of 853.3 g SO42-/m3 d : 140.5 g N/m3 d, which indicated that denitrification bacteria (DB) were normally dominated to complete H2 electron with sulfate bacteria (SRB). The results of molecular microbiology analysis showed that the dominated DB were Rhodocyclus and Hydrogenophaga, and the dominated SRB was Desulfohalobium, under the high influent sulfate concentrations.},
}
@article {pmid30173098,
year = {2018},
author = {Jafari, M and Desmond, P and van Loosdrecht, MCM and Derlon, N and Morgenroth, E and Picioreanu, C},
title = {Effect of biofilm structural deformation on hydraulic resistance during ultrafiltration: A numerical and experimental study.},
journal = {Water research},
volume = {145},
number = {},
pages = {375-387},
doi = {10.1016/j.watres.2018.08.036},
pmid = {30173098},
issn = {1879-2448},
abstract = {Biofilm formation in membrane systems negatively impacts the filtration system performances. This study evaluated how biofilm compression driven by permeate flow increases the hydraulic resistance and leads to reduction in permeate flux. We analysed the effect of biofilm compression on hydraulic resistance and permeate flux through computational models supported by experimental data. Biofilms with homogeneous surface structure were subjected to step-wise changes in flux and transmembrane pressure during compression and relaxation tests. Biofilm thickness under applied forces was measured non-invasively in-situ using optical coherence tomography (OCT). A numerical model of poroelasticity, which couples water flow through the biofilm with biofilm mechanics, was developed to correlate the structural deformation with biofilm hydraulics (permeability and resistance). The computational model enabled extracting mechanical and hydrological parameters corresponding to the experimental data. Homogeneous biofilms under elevated compression forces experienced a significant reduction in thickness while only a slight increase in resistance was observed. This shows that hydraulic resistance of homogeneous biofilms was affected more by permeability decrease due to pore closure than by a decrease in thickness. Both viscoelastic and elastoplastic models could describe well the permanent biofilm deformation. However, for biofilms under study, a simpler elastic model could also be used due to the small irreversible deformations. The elastic moduli fitting the measured data were in agreement with other reported values for biofilm under compression. Biofilm stiffening under larger flow-driven compression forces was observed and described numerically by correlating inversely the elastic modulus with biofilm porosity. The importance of this newly developed method lies in estimation of accurate biofilm mechanical parameters to be used in numerical models for both membrane filtration system and biofouling cleaning strategies. Such model can ultimately be used to identify optimal operating conditions for membrane system subjected to biofouling.},
}
@article {pmid30173020,
year = {2018},
author = {Zeng, XC and He, Z and Chen, X and Cao, QAD and Li, H and Wang, Y},
title = {Effects of arsenic on the biofilm formations of arsenite-oxidizing bacteria.},
journal = {Ecotoxicology and environmental safety},
volume = {165},
number = {},
pages = {1-10},
doi = {10.1016/j.ecoenv.2018.08.079},
pmid = {30173020},
issn = {1090-2414},
abstract = {Arsenite-oxidizing bacteria (AOB) play a key role in the biogeochemical cycle of arsenic in the environment, and are used for the bioremediation of As contaminated groundwater; however, it is not yet known about how arsenic affects biofilm formations of AOB, and how biofilm formations affect bacterial arsenite-oxidizing activities. To address these issues, we isolated seven novel AOB strains from the arsenic-contaminated soils. They can completely oxidize 1.0 mM As(III) in 22-60 h. Their arsenite oxidase sequences show 43-99% identities to those of other known AOB. Strains Cug1, Cug2, Cug3, Cug4, and Cug6 are able to form biofilms with thickness of 15-95 µm, whereas Cug8 and Cug9 cannot form biofilms. It is interesting to see that arsenite inhibited the biofilm formations of heterotrophic AOB strains, but promoted the biofilm formations of autotrophic strains in a concentration-dependent manner. The arsenite-oxidizing rates of Cug1 and Cug4 biofilms are 31.6% and 27.6% lower than those of their suspension cultures, whereas the biofilm activities of other strains are similar to those of their suspension cultures. The biofilm formation significantly promoted the bacterial resistance to arsenic. This work is the first report on the complex correlations among environmental arsenic, bacterial biofilm formations and bacterial arsenite-oxidizing activities. The data highlight the diverse lifestyle of different AOB under arsenic stress, and provide essential knowledge for the screening of efficient AOB strains used for constructions of bioreactors.},
}
@article {pmid30172301,
year = {2018},
author = {Yao, H and Kang, M and Wang, Y and Feng, Y and Kong, S and Cai, X and Ling, Z and Chen, S and Jiao, X and Yin, Y},
title = {An essential role for hfq involved in biofilm formation and virulence in serotype 4b Listeria monocytogenes.},
journal = {Microbiological research},
volume = {215},
number = {},
pages = {148-154},
doi = {10.1016/j.micres.2018.07.001},
pmid = {30172301},
issn = {1618-0623},
abstract = {Regulator factor Hfq has been widely detected among both Gram-positive and Gram-negative bacteria; however, its role in Gram-positive bacteria is less well established and varies among species. In Listeria monocytogenes (Lm), an organism able to adapt to a range of environments and live both saprobiotic and parasitic lifestyles, the role of Hfq is not fully understood. Serotype 4b Listeria monocytogenes strains associated with the majority of listeriosis outbreak, while the function of hfq in serotype 4b strains still not referenced. Here, we constructed hfq deletion and reversion mutants of serotype 4b Lm NTSN and analysed the biological characteristics both in vitro and in vivo. The deletion of hfq resulted in a growth deficiency in medium containing 4.5% ethanol or 1% Triton X-100, and the growth of the mutant was significantly reduced at 4 °C. Furthermore, the hfq deletion dramatically decreased biofilm formation in BHI medium and gastric fluid medium, and reduced the invasion and replication rate into the Caco-2BBe cells and RAW264.7 cells. However, complementation restored the wild-type phenotype. Importantly, mouse infection experiments demonstrated that hfq played a more important role in the colonisation and virulence in serotype 4b strain Lm NTSN than in the serotype 1/2a strain Lm EGDe. Taken together, these results demonstrated that hfq is a novel factor associated with biofilm formation, and plays an essential role in the stress response and pathogenisis in serotype 4b strain Lm NTSN. Our data provide the basis for further research into the function of Hfq in serotype 4b Listeria monocytogenes.},
}
@article {pmid30172295,
year = {2018},
author = {Yang, W and Yan, H and Zhang, J and Gao, Y and Xu, W and Shang, J and Luo, Y},
title = {Inhibition of biofilm formation by Cd2+ on Bacillus subtilis 1JN2 depressed its biocontrol efficiency against Ralstonia wilt on tomato.},
journal = {Microbiological research},
volume = {215},
number = {},
pages = {1-6},
doi = {10.1016/j.micres.2018.06.002},
pmid = {30172295},
issn = {1618-0623},
abstract = {Bacillus subtilis 1JN2 can serve as an effective biocontrol agent against Ralstonia wilt on tomato, but the efficiency of control depends on the levels of heavy metals in the rhizosphere soil. Here, we investigated how the heavy metal Cd2+ affects the biocontrol efficacy of B.subtilis 1JN2 on Ralstonia wilt. We found that low Cd2+ content of 2 mM or lower had no effects on the biofilm formation of 1JN2, while media containing 3 mM or higher Cd2+ levels inhibited biofilm formation. Interestingly, high concentration of Cd2+ (5 mM) showed inhibition of B.subtilis 1JN2 cell growth. We next tested the effects of Cd2+ on the colonization of 1JN2 by supplementing artificial Cd2+ in the tomato rhizosphere in a greenhouse setting. We found that 3 mM Cd2+ in the tomato rhizosphere inhibited the colonization of B.subtilis 1JN2, Only 103 CFU/mL 1JN2 was detected one week post treated with 107 CFU/mL but 105 CFU/mL could be detected without Cd2+ in the soil. The presence of Cd2+ had no effect on the colonization of Ralstonia solanacearum on tomato, but the biocontrol efficacy against Ralstonia wilt by 1JN2 decreased 54.2% when the soil contained 3 mM Cd2+ compared to the control without Cd2+. Taken together, we found that the failure of biofilm formation of Bacillus subtilis 1JN2 that affected by Cd2+ lead to the decrease of its biocontrol efficacy against Ralstonia wilt on tomato.},
}
@article {pmid30149130,
year = {2018},
author = {Lotha, R and Shamprasad, BR and Sundaramoorthy, NS and Ganapathy, R and Nagarajan, S and Sivasubramanian, A},
title = {Zero valent silver nanoparticles capped with capsaicinoids containing Capsicum annuum extract, exert potent anti-biofilm effect on food borne pathogen Staphylococcus aureus and curtail planktonic growth on a zebrafish infection model.},
journal = {Microbial pathogenesis},
volume = {124},
number = {},
pages = {291-300},
doi = {10.1016/j.micpath.2018.08.053},
pmid = {30149130},
issn = {1096-1208},
abstract = {Food plants Hungarian wax pepper (HWP) and Green Bell pepper (GBP), belonging to Capsicum annuum were utilized for biogenic fabrication of zero valent, nano-silver (AgNPs) through a photo-mediation procedure. In the bacterial strains evaluated, HWP/GBP AgNPs demonstrated effective bacteriostatic and bactericidal effect against Staphylococcus aureus. Time kill results portrayed that HWP/GBP nano-silver exhibited comparable bactericidal potency on S. aureus. Anti-biofilm potential of HWP/GBP AgNPs displayed significant effects at sub MIC levels, by triggering 50% biofilm reduction of the food spoilage microbe S. aureus, inferring that the anti-biofilm outcome is not dependent on antibacterial result, and this was confirmed by SEM and fluorescence studies. Histopathological analyses of S. aureus infected zebrafish liver did not display any abnormality changes such as extensive cell death and degeneration, upon treatment with HWP/GBP AgNPs and the zero-valent silver nanoparticles were comparatively less toxic and more operative in restraining the bioburden in S. aureus infected zebrafish model by a >1.7 log fold. Ability of light reduced HWP/GBP AgNPs to alleviate the in vitro and in vivo planktonic mode of growth and curb the biofilm formation of S. aureus is also demonstrated.},
}
@article {pmid30172134,
year = {2018},
author = {Zhang, M and Wang, L and Xu, M and Zhou, H and Wang, S and Wang, Y and Bai, M and Zhang, C},
title = {Selective antibiotic resistance genes in multiphase samples during biofilm growth in a simulated drinking water distribution system: Occurrence, correlation and low-pressure ultraviolet removal.},
journal = {The Science of the total environment},
volume = {649},
number = {},
pages = {146-155},
doi = {10.1016/j.scitotenv.2018.08.297},
pmid = {30172134},
issn = {1879-1026},
abstract = {The aim of this study was to gain comprehensive insights into the characteristics of antibiotic resistance genes (ARGs) in multiphase samples from drinking water distribution pipelines using a simulated biofilm reactor. During 120 d of continuous operation, common parameters and six ARGs (ermA, ermB, aphA2, ampC, sulII, and tetO) in samples of three phases (water, particle, and biofilm) from the reactor were investigated, which demonstrated secondary contamination by ARGs. Abundances of the six ARGs in the reactor effluent increased gradually, and in the 120 d effluent, the relative abundances of aphA2 and sulII were the highest, at 9.9 × 10-4 and 1.3 × 10-3, respectively, with a 1.5-fold and 2.8-fold increase, compared with those in the influent. The relative abundances of the six ARGs in the biofilm phase increased significantly (P < 0.05) at 120 d, which was caused by robust bacteria in biofilm that was newly exposed following the detachment of a large piece of aging biofilm. In the particle phase, four of the ARGs did not change significantly during the 120 d period. The six ARGs in the samples of three phases showed a negative correlation with residual chlorine in the pipe water, which demonstrated that low abundance of ARGs in the samples of three phases was related to the improvement of residual chlorine. The proportion of cultivable bacteria illustrated that the robust and active bacteria were negatively correlated with the six ARGs in the biofilm. Total organic carbon (TOC) in the pipeline showed a positive correlation with the proportion of cultivable bacteria in both the water and biofilm phases, which indicated that a TOC reduction in the pipeline contributed to low abundance of ARGs. With low-pressure ultraviolet (LP-UV) irradiation of 20 mJ/cm2, ARGs in the samples of three phases were efficiently controlled, which showed that LP-UV can be used for ARG removal in terminal water for supplemental bactericidal treatment of pipeline effluent.},
}
@article {pmid30168313,
year = {2018},
author = {Tamayo-Ramos, JA and Rumbo, C and Caso, F and Rinaldi, A and Garroni, S and Notargiacomo, A and Romero-Santacreu, L and Cuesta-López, S},
title = {Analysis of polycaprolactone microfibers as biofilm carriers for biotechnologically-relevant bacteria.},
journal = {ACS applied materials &amp; interfaces},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsami.8b07245},
pmid = {30168313},
issn = {1944-8252},
abstract = {Polymeric electrospun fibers are becoming popular in microbial biotechnology due to their exceptional physicochemical characteristics, biodegradability, surface-to-volume ratio, and compatibility with biological systems, which give them a great potential as microbial supports to be used in production processes or environmental applications. In this work we analyzed and compared the ability of Escherichia coli, Pseudomonas putida, Brevundimonas diminuta, and Sphingobium fuliginis to develop biofilms on different types of polycaprolactone (PCL) microfibers. These bacterial species are relevant in the production of bio-based chemicals, enzymes and proteins for therapeutic use, and bioremediation. The obtained results demonstrated that all selected species were able to attach efficiently to the PCL microfibers. Also, the ability of pure cultures of S. fuliginis (former Flavobacterium sp. ATCC 27551, a very relevant strain in the bioremediation of organophosphorus compounds) to form dense biofilms was observed for the first time, opening the possibility of new applications for this microorganism. This material showed to have a high microbial loading capacity, regardless of the mesh density and fiber diameter. A comparative analysis between PCL and polylactic acid (PLA) electrospun microfibers indicated that both surfaces have a similar bacterial loading capacity, but the former material showed higher resistance to microbial degradation than PLA.},
}
@article {pmid30168107,
year = {2018},
author = {Xu, G and Abdullah Al, M and Sikder, MNA and Warren, A and Xu, H},
title = {Identifying indicator redundancy of biofilm-dwelling protozoa for bioassessment in marine ecosystems.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-018-3063-2},
pmid = {30168107},
issn = {1614-7499},
abstract = {A multivariate peeling method of data analysis was applied to determine indicator redundancy and for identifying indicator units (IUs) among biofilm-dwelling ciliate communities used for bioassessment of marine water quality. Samples were taken monthly over a 1-year period at four stations in coastal waters of the Yellow Sea: one heavily polluted, one moderately polluted, one intermittently polluted, and one unpolluted. Four IUs (IU1-4) were identified consisting of 22, 13, 14, and 17 species, respectively, out of a total of 144 species. The IUs showed significant correlation with temporal and spatial variations in environmental variables. The redundancy levels of IUs were interchangeable in time and space. However, IU1 and IU2 generally dominated the communities in moderately and intermittently polluted areas during cool (e.g., early spring, late autumn, and winter) and warm (late spring and early autumn) seasons; IU3 dominated in warm seasons (e.g., late spring to autumn) in the heavily polluted area; and IU4 mainly dominated the samples in the unpolluted and moderately polluted areas during the late summer and early autumn. Furthermore, different trophic-functional groupings were represented within the four IUs and these were generally associated with water quality status. These findings suggest that there is high indicator redundancy in marine biofilm-dwelling ciliate communities subjected to different levels of water quality.},
}
@article {pmid30166817,
year = {2018},
author = {Pakshir, K and Ravandeh, M and Khodadadi, H and Motamedifar, M and Zomorodian, K and Alipour, S},
title = {Evaluation of Exoenzyme Activities, Biofilm Formation, and Co-hemolytic Effect in Clinical Isolates of Candida parapsilosis Species Complex.},
journal = {Journal of global infectious diseases},
volume = {10},
number = {3},
pages = {163-165},
doi = {10.4103/jgid.jgid_93_17},
pmid = {30166817},
issn = {0974-777X},
abstract = {Candida parapsilosis species complex is considered as important emerging pathogens and little is known about their pathogenicity factors and co-hemolytic activity with different bacteria species. The aim of this study was to determine in vitro exoenzyme activities, biofilm formation, and co-hemolytic effect of different bacteria species on clinical C. parapsilosis complex isolates. In total, 67 C. parapsilosis complex isolates consist of C. parapsilosis sensu stricto 63/67 and Candida orthopsilosis 4/67 were used in this study. To determine the hemolytic activity of these species, Sabouraud dextrose sheep blood agar was used. Evaluation of the CAMP-like phenomenon carried out in the presence of Staphylococcus aureus, Staphylococcus saprophyticus, Staphylococcus epidermidis, and Streptococcus agalactiae. Tube test method with ethylenediaminetetraacetic acid-rabbit plasma was used to determine coagulase activity, and biofilm formation was assessed by the tube method in assist of Sabouraud glucose broth (8%) medium. Fisher's exact tests were used for data statistical analysis. Sixty-six of 67 (98.5%) and 3/67 (4.5%) of the species showed hemolysin and coagulase activity, respectively. Fifty-five of 67 (82.1%) of species had ability for biofilm formation, and none of the samples exhibited co-hemolytic effect in the presence of four mentioned bacteria. No significant difference was found between the level of enzyme production and biofilm formation among the isolates.},
}
@article {pmid30166167,
year = {2018},
author = {Liu, L and Yan, Y and Feng, L and Zhu, J},
title = {Quorum sensing asaI mutants affect spoilage phenotypes, motility, and biofilm formation in a marine fish isolate of Aeromonas salmonicida.},
journal = {Food microbiology},
volume = {76},
number = {},
pages = {40-51},
doi = {10.1016/j.fm.2018.04.009},
pmid = {30166167},
issn = {1095-9998},
abstract = {Microbial spoilage is associated with the regulation of quorum sensing (QS). A. salmonicida AE03 with QS mediated acylated homoserine lactones (AHLs) activity was isolated from spoiled large yellow croaker (Pseudosciaena crocea). In this study the activity and role of AHLs in spoilage phenotypes, motility and biofilm formation of AE03 were investigated. The strain AE03 could induce Chromobacterium violaceum CV026 to produce the violacein pigment both at 28 °C and 4 °C in a density-dependent manner. Five types of AHLs were detected in AE03 culture by LC-MS/MS analysis, and N-butanoyl-l-homoserine lactone (C4-HSL) was a major signal molecule, reaching the highest concentration when incubated for 30 h at 28 °C. An asaI-mutant, constructed by a suicide plasmid, failed to produce short chain AHLs signal. Compared with wild type (WT) strain, the production of trimethylamine (TMA), biogenic amino and protease significantly increased in asaI-mutant during the exponential and stationary phase, while the growth rate did not differ. Swimming motility in asaI-mutant was comparatively stronger than that of WT strain, whereas, asaI-mutant resulted in the decrease of maturing biofilm. Furthermore, supplementation of exogenous C4-HSL restored the production of spoilage metablites, protease and biofilm formation in mutant. In accordance with the effect of asaI deletion on the spoilage phenotypes and motility, asaI-mutant was showed to significantly up-regulate the transcript levels of torA, cadA and fliR, as well as asaR, indicating that C4-HSL could be involved in the modulation of the spoilage related enzymes and flagella. Indeed, the asaI-mutant promoted the spoilage progress of fish fillets stored at 4 °C, while exogenous C4-HSL repressed the sensory change and TVB-N accumulation. The present study highlighted that AsaI/C4-HSL was an important regulator in spoilage, motility and biofilm formation of A. salmonicida, and spoilage potential was under the negative control of AsaI/AsaR-type system.},
}
@article {pmid30166152,
year = {2018},
author = {Tango, CN and Akkermans, S and Hussain, MS and Khan, I and Van Impe, J and Jin, YG and Oh, DH},
title = {Modeling the effect of pH, water activity, and ethanol concentration on biofilm formation of Staphylococcus aureus.},
journal = {Food microbiology},
volume = {76},
number = {},
pages = {287-295},
doi = {10.1016/j.fm.2018.06.006},
pmid = {30166152},
issn = {1095-9998},
abstract = {In this work, the effect of environmental factors on Staphylococcus aureus (ATCC 13150) biofilm formation in tryptic soy broth was investigated under different ranges of pH (3.0-9.5), ethanol concentration (EtOH 0.0-20.0%), and aw (NaCl, 0.866-0.992). Biofilm formation was quantified using the crystal violet staining method and optical density (OD: 590 nm) measurements. Biofilm formation was significantly stronger at pH and aw close to S. aureus optimal growth conditions, while it was high at EtOH around 2.5-3.5%. Data sets from the difference between the OD measurements of the test and control (ΔOD) were fitted to the cardinal parameter model (CPM) and cardinal parameter model with inflection (CPMI) to describe the effect of the environmental factors. The models showed good quality of fit for the experimental data in terms of calculated RMSE, with the latter ranging from 0.276 to 0.455. CPM gave a good quality of fit compared to CPMI for the environmental factors tested. Optimal pH was close to neutral (6.76-6.81) and biofilm formation was possible till pH = 3.81-3.78 for CPM and CPMI, respectively. Optimum EtOH and aw conditions for biofilm formation were in the range of 1.99-2.75 and 0.98-0.97, respectively. Predicted OD values observed using strain 13150 were very closely correlated to the OD values predicted with strain 12600 with R2 of 0.978, 0.991, and 0.947 for pH, EtOH, and aw, respectively. The cultivable bacterial cells within the biofilm were enumerated using standard plate counting and a linear model was applied to correlate the attached biofilm cells to ΔOD of biofilm formation. It was found that the biofilm formation correlated with S. aureus population growth. At 2.5-3.5% of EtOH the maximum population density was lower than that observed at 0.0% of EtOH. As 2.5-3.5% of EtOH initiated a stronger biofilm formation, biofilm formation seems to be induced by ethanol stress. The development of cardinal parameter models to describe the effect environmental factors of importance to biofilm formation, offers a promising predictive microbiology approach to decrypting the S. aureus population growth and survival ability on food processing surfaces.},
}
@article {pmid30161132,
year = {2018},
author = {Tasse, J and Trouillet-Assant, S and Josse, J and Martins-Simões, P and Valour, F and Langlois-Jacques, C and Badel-Berchoux, S and Provot, C and Bernardi, T and Ferry, T and Laurent, F},
title = {Association between biofilm formation phenotype and clonal lineage in Staphylococcus aureus strains from bone and joint infections.},
journal = {PloS one},
volume = {13},
number = {8},
pages = {e0200064},
doi = {10.1371/journal.pone.0200064},
pmid = {30161132},
issn = {1932-6203},
abstract = {Biofilm formation is a critical virulence factor responsible for treatment failure and chronicity in orthopaedic device-related infections (ODIs) caused by Staphylococcus aureus. Clonal lineages differ in terms of their biofilm forming capacities. The aim of this study was to investigate the correlation between the clonal complex (CC) affiliation and biofilm phenotype of 30 clinical S. aureus isolates responsible of ODI based on i) early biofilm formation using BioFilm Ring Test® and mature biofilm formation using crystal violet assays, ii) biofilm composition using DNase and proteinase K activity, and iii) prevention of biofilm formation by cloxacillin, teicoplanin and vancomycin using Antibiofilmogram® (biofilm minimal inhibitory concentration-bMIC). In terms of early biofilm formation, the CC30 strains were significantly slower than the CC5, CC15 and CC45 strains. CC45 strains produced significantly more mature biofilm than other group of strains did. The formation of biofilms was highly dependent on the presence of extracellular DNA in the CC5, CC15 and CC30 strains whereas it was mostly dependent on the presence of proteins in CC45. Finally, the CC30 group highlighted higher proportion of susceptible (bMIC < breakpoints of EUCAST guidelines) for cloxacillin, teicoplanin and vancomycin compared to the other CCs. These results demonstrate that the biofilm phenotype of clinical S. aureus isolates from ODIs is strongly related to their respective CC affiliation.},
}
@article {pmid30160948,
year = {2018},
author = {Vosshage, ATL and Neu, TR and Gabel, F},
title = {Plastic alters biofilm quality as food resource of the freshwater gastropod Radix balthica.},
journal = {Environmental science &amp; technology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.est.8b02470},
pmid = {30160948},
issn = {1520-5851},
abstract = {High amounts of plastic debris enter and accumulate in freshwater systems across the globe. The plastic contamination of benthic habitats in lakes and running waters poses a potential threat to freshwater ecosystems. This study investigates the effects of plastic on two trophic levels of the aquatic food web: primary production, i.e. epiplastic biofilm, and primary consumption, i.e. a benthic invertebrate grazer. Two plastic types, Polymethyl methacrylate (PMMA) and Polycarbonate (PC), and glass (control) were used as substrata for natural biofilm establishment. PMMA and PC are e.g. intensively used in the automobile, construction and electronical industry, in cosmetics (PMMA) and CDs and DVDs (PC). These biofilms were fed to the freshwater gastropod Radix balthica (Linnaeus 1758) in a laboratory grazing experiment. Biofilm structure and composition were observed using confocal laser scanning microscopy before the grazing experiment. Sublethal effects on R. balthica were observed measuring consumption of biofilm and growth rates. The biofilm composition on PMMA significantly differed compared to PC and glass. The grazing experiments showed limited biofilm consumption and lower growth rates of R. balthica in both plastic treatments. Concluding, plastic in freshwaters has a direct effect on the primary production and an indirect effect on higher trophic levels.},
}
@article {pmid30160784,
year = {2018},
author = {Borsodi, AK and Anda, D and Makk, J and Krett, G and Dobosy, P and Büki, G and Erőss, A and Mádl-Szőnyi, J},
title = {Biofilm forming bacteria and archaea in thermal karst springs of Gellért Hill discharge area (Hungary).},
journal = {Journal of basic microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1002/jobm.201800138},
pmid = {30160784},
issn = {1521-4028},
abstract = {The Buda Thermal Karst System (BTKS) is an extensive active hypogenic cave system located beneath the residential area of the Hungarian capital. At the river Danube, several thermal springs discharge forming spring caves. To reveal and compare the morphological structure and prokaryotic diversity of reddish-brown biofilms developed on the carbonate rock surfaces of the springs, scanning electron microscopy (SEM), and molecular cloning were applied. Microbial networks formed by filamentous bacteria and other cells with mineral crystals embedded in extracellular polymeric substances were observed in the SEM images. Biofilms were dominated by prokaryotes belonging to phyla Proteobacteria, Chloroflexi and Nitrospirae (Bacteria) and Thaumarchaeota (Archaea) but their abundance showed differences according to the type of the host rock, geographic distance, and different water exchange. In addition, representatives of phyla Acidobacteria, Actinobacteria, Caldithrix, Cyanobacteria, Firmicutes Gemmatimonadetes, and several candidate divisions of Bacteria as well as Crenarchaeota and Euryarchaeota were detected in sample-dependent higher abundance. The results indicate that thermophilic, anaerobic sulfur-, sulfate-, nitrate-, and iron(III)-reducing chemoorganotrophic as well as sulfur-, ammonia-, and nitrite-oxidizing chemolithotrophic prokaryotes can interact in the studied biofilms adapted to the unique and extreme circumstances (e.g., aphotic and nearly anoxic conditions, oligotrophy, and radionuclide accumulation) in the thermal karst springs.},
}
@article {pmid30159221,
year = {2018},
author = {Kord, M and Ardebili, A and Jamalan, M and Jahanbakhsh, R and Behnampour, N and Ghaemi, EA},
title = {Evaluation of Biofilm Formation and Presence of Ica Genes in Staphylococcus epidermidis Clinical Isolates.},
journal = {Osong public health and research perspectives},
volume = {9},
number = {4},
pages = {160-166},
doi = {10.24171/j.phrp.2018.9.4.04},
pmid = {30159221},
issn = {2210-9099},
abstract = {Objectives: Biofilm formation is one of the important features of Staphylococcus epidermidis, particularly in nosocomial infections. We aimed to investigate the biofilm production by phenotypic methods and the presence of ica genes in S epidermidis.<br><br>Methods: A total of 41 S epidermidis isolates were recovered from different clinical specimens. Biofilm formation was evaluated by microtiter plate, tube method and Congo red agar method. The presence of icaA and icaD genes was investigated by PCR. Validity of methods (sensitivity and specificity), and metrics for test performance (positive/negative predictive value, and positive/negative likelihood ratio) were determined.<br><br>Results: By both microtiter plate and tube method, 53.6% of S epidermidis isolates were able to produce biofilm, whilst only 24.4% of isolates provided a biofilm phenotype on Congo red agar plates. icaA and icaD genes were found in 100% and 95.1% of isolates, respectively. Biofilm phenotypes accounted for 4.8% by microtiter plate assay, despite the absence of the ica gene. Congo red agar and PCR exhibited a lower sensitivity (18% and 45.5%, respectively) for identifying the biofilm phenotype in comparison to microtiter plate.<br><br>Conclusion: The microtiter plate method remains generally a better tool to screen biofilm production in S epidermidis. In addition, the ability of S epidermidis to form biofilm is not always dependent on the presence of ica genes, highlighting the importance of ica-independent mechanisms of biofilm formation. The use of reliable methods to specifically detect biofilms can be helpful to treat the patients affected by such problematic bacteria.},
}
@article {pmid30159052,
year = {2018},
author = {Abdel Halim, RM and Kassem, NN and Mahmoud, BS},
title = {Detection of Biofilm Producing Staphylococci among Different Clinical Isolates and Its Relation to Methicillin Susceptibility.},
journal = {Open access Macedonian journal of medical sciences},
volume = {6},
number = {8},
pages = {1335-1341},
doi = {10.3889/oamjms.2018.246},
pmid = {30159052},
issn = {1857-9655},
abstract = {AIMS: To evaluate three in vitro phenotypic methods; tissue culture plate, tube method, and Congo red agar for detection of biofilm formation in staphylococci and assess the relation of biofilm formation with methicillin resistance and anti-microbial resistance.<br><br>METHODS: The study included 150 staphylococcal isolates. Biofilm detection in staphylococci was performed using tissue culture plate, tube method, and Congo red agar.<br><br>RESULTS: Tissue culture plate, tube method, and Congo red agar detected 74%, 42.7%, and 1.3% biofilm producing staphylococci respectively. S. aureus isolates were more common biofilm producers (53.2%) than CONS (46.8%). Biofilm production in CONS species was highest in S. hemolyticus (57.7%). Tube method was 51.4% sensitive, 82.1% specific. As for Congo red agar, sensitivity was very low (0.9%), but specificity was 97.4%. Biofilm producers were mostly; isolated from blood specimens and detected in methicillin-resistant strains 96/111 (86.5%). They were resistant to most antibiotics except vancomycin and linezolid.<br><br>CONCLUSIONS: Tissue culture plate is a more quantitative and reliable method for detection of biofilm producing staphylococci compared to tube method and Congo red agar. Hence, it can still be used as a screening method for biofilm detection. Vancomycin and Linezolid are the most sensitive antibiotics among biofilm producing staphylococci.},
}
@article {pmid30158585,
year = {2018},
author = {Tasse, J and Cara, A and Saglio, M and Villet, R and Laurent, F},
title = {A steam-based method to investigate biofilm.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {13040},
doi = {10.1038/s41598-018-31437-y},
pmid = {30158585},
issn = {2045-2322},
abstract = {Biofilm has become a major topic of interest in medical, food, industrial, and environmental bacteriology. To be relevant, investigation of biofilm behavior requires effective and reliable techniques. We present herein a simple and robust method, adapted from the microplate technique, in which steam is used as a soft washing method to preserve biofilm integrity and to improve reproducibility of biofilm quantification. The kinetics of steam washing indicated that the method is adapted to remove both planktonic bacteria and excess crystal violet (CV) staining for S. aureus, S. epidermidis, S. carnosus, P. aeruginosa, and E. coli biofilm. Confocal laser scanning microscopy confirmed that steam washing preserved the integrity of the biofilm better than pipette-based washing. We also investigated the measurement of the turbidity of biofilm resuspended in phosphate-buffered saline (PBS) as an alternative to staining with CV. This approach allows the discrimination of biofilm producer strains from non-biofilm producer strains in a way similar to CV staining, and subsequently permits quantification of viable bacteria present in biofilm by culture enumeration from the same well. Biofilm quantification using steam washing and PBS turbidity reduced the technical time needed, and data were highly reproducible.},
}
@article {pmid30158390,
year = {2018},
author = {Morohoshi, T and Oi, T and Aiso, H and Suzuki, T and Okura, T and Sato, S},
title = {Biofilm Formation and Degradation of Commercially Available Biodegradable Plastic Films by Bacterial Consortiums in Freshwater Environments.},
journal = {Microbes and environments},
volume = {},
number = {},
pages = {},
doi = {10.1264/jsme2.ME18033},
pmid = {30158390},
issn = {1347-4405},
abstract = {We investigated biofilm formation on biodegradable plastics in freshwater samples. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) was covered by a biofilm after an incubation in freshwater samples. A next generation sequencing analysis of the bacterial communities of biofilms that formed on PHBH films revealed the dominance of the order Burkholderiales. Furthermore, Acidovorax and Undibacterium were the predominant genera in most biofilms. Twenty-five out of 28 PHBH-degrading isolates were assigned to the genus Acidovorax, while the other three were assigned to the genera Undibacterium and Chitinimonas. These results demonstrated that the order Burkholderiales in biofilms functions as a degrader of PHBH films.},
}
@article {pmid30158309,
year = {2018},
author = {Michels, J and Stippkugel, A and Lenz, M and Wirtz, K and Engel, A},
title = {Rapid aggregation of biofilm-covered microplastics with marine biogenic particles.},
journal = {Proceedings. Biological sciences},
volume = {285},
number = {1885},
pages = {},
doi = {10.1098/rspb.2018.1203},
pmid = {30158309},
issn = {1471-2954},
abstract = {Ocean plastic pollution has resulted in a substantial accumulation of microplastics in the marine environment. Today, this plastic litter is ubiquitous in the oceans, including even remote habitats such as deep-sea sediments and polar sea ice, and it is believed to pose a threat to ecosystem health. However, the concentration of microplastics in the surface layer of the oceans is considerably lower than expected, given the ongoing replenishment of microplastics and the tendency of many plastic types to float. It has been hypothesized that microplastics leave the upper ocean by aggregation and subsequent sedimentation. We tested this hypothesis by investigating the interactions of microplastics with marine biogenic particles collected in the southwestern Baltic Sea. Our laboratory experiments revealed a large potential of microplastics to rapidly coagulate with biogenic particles, which substantiates this hypothesis. Together with the biogenic particles, the microplastics efficiently formed pronounced aggregates within a few days. The aggregation of microplastics and biogenic particles was significantly accelerated by microbial biofilms that had formed on the plastic surfaces. We assume that the demonstrated aggregation behaviour facilitates the export of microplastics from the surface layer of the oceans and plays an important role in the redistribution of microplastics in the oceans.},
}
@article {pmid30154782,
year = {2018},
author = {Tan, L and Zhao, F and Han, Q and Zhao, A and Malakar, PK and Liu, H and Pan, Y and Zhao, Y},
title = {High Correlation Between Structure Development and Chemical Variation During Biofilm Formation by Vibrio parahaemolyticus.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1881},
doi = {10.3389/fmicb.2018.01881},
pmid = {30154782},
issn = {1664-302X},
abstract = {The complex three-dimensional structure of biofilms is supported by extracellular polymeric substances (EPSs) and additional insight on chemical variations in EPS and biofilm structure development will inform strategies for control of biofilms. Vibrio parahaemolyticus VPS36 biofilm development was studied using confocal laser scanning microscopy (CLSM) and Raman spectroscopy (RM). The structural parameters of the biofilm (biovolume, mean thickness, and porosity) were characterized by CLSM and the results showed that VPS36 biofilm formed dense structures after 48 h incubation. There were concurrent variations in carbohydrates and nucleic acids contents in the EPS as evidenced by RM. The Raman intensities of the chemical component in EPS, measured using Pearson's correlation coefficient, were positively correlated with biovolume and mean thickness, and negatively correlated with porosity. The Raman intensity for carbohydrates correlated closely with mean thickness (p-value < 0.01) and the Raman intensity for nucleic acid correlated closely with porosity (p-value < 0.01). Additional evidence for these correlations were confirmed using scanning electron microscopic (SEM) and crystal violet staining.},
}
@article {pmid30154262,
year = {2018},
author = {Chodur, DM and Coulter, P and Isaacs, J and Pu, M and Fernandez, N and Waters, CM and Rowe-Magnus, DA},
title = {Environmental Calcium Initiates a Feed-Forward Signaling Circuit That Regulates Biofilm Formation and Rugosity in Vibrio vulnificus.},
journal = {mBio},
volume = {9},
number = {4},
pages = {},
doi = {10.1128/mBio.01377-18},
pmid = {30154262},
issn = {2150-7511},
abstract = {Poor clinical outcomes (disfigurement, amputation, and death) and significant economic losses in the aquaculture industry can be attributed to the potent opportunistic human pathogen Vibrio vulnificusV. vulnificus, as well as the bivalves (oysters) it naturally colonizes, is indigenous to estuaries and human-inhabited coastal regions and must endure constantly changing environmental conditions as freshwater and seawater enter, mix, and exit the water column. Elevated cellular c-di-GMP levels trigger biofilm formation, but relatively little is known regarding the environmental signals that initiate this response. Here, we show that calcium is a primary environmental signal that specifically increases intracellular c-di-GMP concentrations, which in turn triggers expression of the brp extracellular polysaccharide that enhances biofilm formation. A transposon screen for the loss of calcium-induced PbrpA expression revealed CysD, an enzyme in the sulfate assimilation pathway. Targeted disruption of the pathway indicated that the production of a specific metabolic intermediate, 3'-phosphoadenosine 5'-phosphosulfate (PAPS), was required for calcium-induced PbrpA expression and that PAPS was separately required for development of the physiologically distinct rugose phenotype. Thus, PAPS behaves as a second messenger in V. vulnificus Moreover, c-di-GMP and BrpT (the activator of brp expression) acted in concert to bias expression of the sulfate assimilation pathway toward PAPS and c-di-GMP accumulation, establishing a feed-forward regulatory loop to boost brp expression. Thus, this signaling network links extracellular calcium and sulfur availability to the intracellular second messengers PAPS and c-di-GMP in the regulation of V. vulnificus biofilm formation and rugosity, survival phenotypes underpinning its evolution as a resilient environmental organism.IMPORTANCE The second messenger c-di-GMP is a key regulator of bacterial physiology. The V. vulnificus genome encodes nearly 100 proteins predicted to make, break, and bind c-di-GMP. However, relatively little is known regarding the environmental signals that regulate c-di-GMP levels and biofilm formation in V. vulnificus Here, we identify calcium as a primary environmental signal that specifically increases intracellular c-di-GMP concentrations, which in turn triggers brp-mediated biofilm formation. We show that PAPS, a metabolic intermediate of the sulfate assimilation pathway, acts as a second messenger linking environmental calcium and sulfur source availability to the production of another intracellular second messenger (c-di-GMP) to regulate biofilm and rugose colony formation, developmental pathways that are associated with environmental persistence and efficient bivalve colonization by this potent human pathogen.},
}
@article {pmid30153549,
year = {2018},
author = {Liu, X and Wang, L and Pang, L},
title = {Application of a novel strain Corynebacterium pollutisoli SPH6 to improve nitrogen removal in an anaerobic/aerobic-moving bed biofilm reactor (A/O-MBBR).},
journal = {Bioresource technology},
volume = {269},
number = {},
pages = {113-120},
doi = {10.1016/j.biortech.2018.08.076},
pmid = {30153549},
issn = {1873-2976},
abstract = {A novel bacterium Corynebacterium pollutisoli SPH6 was added in A/O-MBBR system to explore its potential in nitrogen removal. Sodium acetate was found to be its favorable carbon sources compared to glucose, sucrose and methanol. Response surface methodology analysis revealed that SPH6 has the maximum specific degradation rate of total nitrogen (4.9302 mg N/(mg·cells·h-1)) with the temperature of 30.5 °C, pH of 7.97, inoculation ratio of 7.73% and the ratio of chemical oxygen demand and total nitrogen (COD/TN) of 7.77. The inoculation of SPH6 in A/O-MBBR demonstrated that the strain SPH6 could substantially improve the TN removal efficiency with 20% averagely. The results of high-throughput sequencing showed that the inoculation of SPH6 would essentially improve the microbial community involving nitrogen removal genus such as Hydrogenophaga, Desulfuromonas, and Desulfomicrobium. This study is of importance in providing microbial sources for bioaugmentation in nitrogen removal of wastewater treatment.},
}
@article {pmid30153487,
year = {2018},
author = {Woischnig, AK and Gonçalves, LM and Ferreira, M and Kuehl, R and Kikhney, J and Moter, A and Ribeiro, IAC and Almeida, AJ and Khanna, N and Francisca Bettencourt, A},
title = {Acrylic microparticles increase daptomycin intracellular and in vivo anti-biofilm activity against Staphylococcus aureus.},
journal = {International journal of pharmaceutics},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijpharm.2018.08.048},
pmid = {30153487},
issn = {1873-3476},
}
@article {pmid30153380,
year = {2018},
author = {Yong, YY and Dykes, G and Lee, SM and Choo, WS},
title = {Biofilm inhibiting activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14091},
pmid = {30153380},
issn = {1365-2672},
abstract = {AIMS: To investigate the biofilm inhibitory activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms.<br><br>METHODS AND RESULTS: The pulp of red pitahaya and the leaves of red spinach were extracted using methanol followed by sub-fractionation to obtain betacyanin fraction. The anti-biofilm activity was examined using broth microdilution assay on polystyrene surfaces and expressed as minimum biofilm inhibitory concentration (MBIC). The betacyanin fraction from red spinach showed better anti-biofilm activity (MBIC: 0.313-1.25 mg mL-1) against five S. aureus strains while the betacyanin fraction from red pitahaya showed better anti-biofilm activity (MBIC: 0.313-0.625 mg mL-1) against four P. aeruginosa strains. Both betacyanin fraction significantly reduced hydrophobicity of S. aureus and P. aeruginosa strains. Numbers of S. aureus and P. aeruginosa attached to polystyrene were also reduced without affecting their cell viability.<br><br>CONCLUSION: Betacyanins can act as anti-biofilm agents against the initial step of biofilm formation, particularly on a hydrophobic surface like polystyrene.<br><br>This study is the first to investigate the use of betacyanin as a biofilm inhibitory agent. Betacyanin could potentially be used to reduce the risk of biofilm-associated infections. This article is protected by copyright. All rights reserved.},
}
@article {pmid30153375,
year = {2018},
author = {Rossi, E and Paroni, M and Landini, P},
title = {Biofilm and motility in response to environmental and host-related signals in Gram negative opportunistic pathogens.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14089},
pmid = {30153375},
issn = {1365-2672},
abstract = {Most bacteria can switch between a planktonic, sometimes motile, form and a biofilm mode, in which bacterial cells can aggregate and attach to a solid surface. The transition between these two forms represents an example of bacterial adaptation to environmental signals and stresses. In &quot;environmental pathogens&quot;, namely, environmental bacteria that are also able to cause disease in animals and humans, signals associated either with the host or with the external environment, such as temperature, oxygen availability, nutrient concentrations etc., play a major role in triggering the switch between the motile and the biofilm mode, via complex regulatory mechanisms that control flagellar synthesis and motility, and production of adhesion factors. In this review article, we present examples of how environmental signals can impact biofilm formation and cell motility in the Gram negative bacteria Pseudomonas aeruginosa, Escherichia coli, and in the Burkholderia genus, and how the switch between motile and biofilm mode can be an essential part of a more general process of adaptation either to the host or to the external environment. This article is protected by copyright. All rights reserved.},
}
@article {pmid30149732,
year = {2018},
author = {Gerbersdorf, SU and Wieprecht, S and Thom, M and Paterson, DM and Scheffler, M},
title = {New insights into MagPI: a promising tool to determine the adhesive capacity of biofilm on the mesoscale.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-12},
doi = {10.1080/08927014.2018.1476971},
pmid = {30149732},
issn = {1029-2454},
abstract = {The adhesiveness and stability of ubiquitously distributed biofilms is a significant issue in many areas such as ecology, biotechnology and medicine. The magnetic particle induction (MagPI) system allows precise determinations of biofilm adhesiveness at high temporal and spatial resolution on the mesoscale. This paper concerns several technical aspects to further improve the performance of this powerful experimental approach and enhance the range of MagPI applications. First, several electromagnets were built to demonstrate the influence of material and geometry with special regard to core remanence and magnetic strength. Secondly, the driving force to lift up the particles was evaluated and it was shown that both the magnetic field strength and the magnetic field gradient are decisive in the physics of the MagPI approach. The intricate combination of these two quantities was demonstrated with separate experiments that add permanent magnets to the MagPI system.},
}
@article {pmid30148865,
year = {2018},
author = {Tran, VN and Dasagrandhi, C and Truong, VG and Kim, YM and Kang, HW},
title = {Antibacterial activity of Staphylococcus aureus biofilm under combined exposure of glutaraldehyde, near-infrared light, and 405-nm laser.},
journal = {PloS one},
volume = {13},
number = {8},
pages = {e0202821},
doi = {10.1371/journal.pone.0202821},
pmid = {30148865},
issn = {1932-6203},
abstract = {Healthcare-associated infections have increasingly become problematic in the endoscopic procedures resulting in several severe diseases such as carbapenem-resistant Enterobacteriaceae (CRE)-related infections, pneumonia, and bacteremia. Especially, some bacterial strains are resistant to traditional antimicrobials. Therefore, the necessity of developing new antibiotics or management to deal with bacterial infections has been increasing. The current study combined a low concentration of glutaraldehyde (GTA) with near-infrared (NIR) light and 405-nm laser to entail antibacterial activity on Staphylococcus aureus biofilm. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and colony forming unit (CFU) counting were used to quantify the viable cells while fluorescent and scanning electron microscopic images were used to qualitatively evaluate the cell membrane integrity and structural deformation, respectively. Practically, S. aureus biofilm was highly susceptible (7% cell viability and 6.8-log CFU/cm2 bacterial reduction for MTT assay and CFU analysis, respectively) to the combination of GTA (0.1%), NIR light (270 J/cm2), and 405-nm laser (288 J/cm2) exposure. GTA could form either DNA-protein or protein-protein crosslinks to inhibit DNA and protein synthesis. The NIR light induced the thermal damage on protein/enzymes while 405-nm laser could induce reactive oxygen species (ROS) to damage the bacterial membrane. Thus, the proposed technique may be a feasible modality for endoscope cleaning to prevent any secondary infection in the healthcare industry.},
}
@article {pmid30142888,
year = {2018},
author = {Mensi, M and Cochis, A and Sordillo, A and Uberti, F and Rimondini, L},
title = {Biofilm Removal and Bacterial Re-Colonization Inhibition of a Novel Erythritol/Chlorhexidine Air-Polishing Powder on Titanium Disks.},
journal = {Materials (Basel, Switzerland)},
volume = {11},
number = {9},
pages = {},
doi = {10.3390/ma11091510},
pmid = {30142888},
issn = {1996-1944},
abstract = {Air-polishing with low abrasiveness powders is fast arising as a valid and mini-invasive instrument for the management of biofilm colonizing dental implants. In general, the reported advantage is the efficient removal of plaque with respect to the titanium integrity. In the present study, we evaluated the in situ plaque removal and the preventive efficacy in forestalling further infection of an innovative erythritol/chlorhexidine air-polishing powder and compared it with sodium bicarbonate. Accordingly, two peri-implantitis-linked biofilm formers, strains Staphylococcus aureus and Aggregatibacter actinomycetemcomitans, were selected and used to infect titanium disks before and after the air-polishing treatment to test its ability in biofilm removal and re-colonization inhibition, respectively. Biofilm cell numbers and viability were assayed by colony-forming unit (CFU) count and metabolic-colorimetric (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) (XTT) assay. Results demonstrated that air-polishing performed with either sodium bicarbonate or erythritol/chlorhexidine was effective in reducing bacteria biofilm viability and number on pre-infected specimens, thus showing a similar ability in counteracting existing infection in situ; on the other hand, when air-polished pre-treated disks were infected, only erythritol/chlorhexidine powder showed higher post-treatment biofilm re-growth inhibition. Finally, surface analysis via mechanical profilometry failed to show an increase in titanium roughness, regardless of the powder selected, thus excluding any possible surface damage due to the use of either sodium bicarbonate or erythritol/chlorhexidine.},
}
@article {pmid30142702,
year = {2018},
author = {Ely, VL and Vargas, AC and Costa, MM and Oliveira, HP and Pötter, L and Reghelin, MA and Fernandes, AW and Pereira, DIB and Sangioni, LA and Botton, SA},
title = {Moraxella bovis, Moraxella ovis and Moraxella bovoculi: Biofilm formation and lysozyme activity.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14086},
pmid = {30142702},
issn = {1365-2672},
abstract = {AIMS: This study aimed to verify the formation of biofilms by Moraxella (Mor.) bovis, Moraxella ovis and Moraxella bovoculi isolates from ruminants. In addition, the lysozyme activity against the isolates of Mor. bovis, Mor. ovis and Mor. bovoculi in free form and in biofilms was determined.<br><br>METHODS AND RESULTS: In this study, fifty-four isolates of Moraxella spp. obtained from bovine and ovine clinical samples were evaluated in vitro for capacity of biofilm formation and lysozyme susceptibility in planktonic and sessile cells. In addition, biofilms produced by four Moraxella spp. isolates were visualized under scanning electron microscope. It was possible to demonstrate, for the first time, the ability to form biofilms by Mor. ovis and Mor. bovoculi. The isolates of Moraxella spp. have the capacity to form biofilms in different intensities, varying among weak, moderate and strong. It was verified that the lysozyme shows activity on Moraxella spp. in planktonic form. However, on biofilms there was a reduction in the production, but without impairing its formation, and on consolidated biofilms the lysozyme did not have the capacity to eradicate the preformed biofilms.<br><br>CONCLUSIONS: This work shows the capacity of biofilm formation by Moraxella species of veterinary importance. The lysozyme susceptibility of Moraxella spp. in planktonic form shows that this enzyme has bacteriostatic activity on this microorganism and it reduced the production of biofilms.<br><br>Based on the results, it is possible to infer that the biofilm formation capacity by Moraxella spp. and the resistance to lysozyme concentrations equal to or greater than the physiological levels of the ruminant tear may be linked not only to the capacity to colonize the conjunctiva, but also to remain in this place even after healing of the lesions, being a reservoir of Moraxella spp. in a herd. This article is protected by copyright. All rights reserved.},
}
@article {pmid30142222,
year = {2018},
author = {Santos, SS and Augusto, DG and Alves, PAC and Pereira, JS and Duarte, LMB and Melo, PC and Gross, E and Kaneto, CM and Silva, A and Santos, JL},
title = {Trichoderma asperelloides ethanolic extracts efficiently inhibit Staphylococcus growth and biofilm formation.},
journal = {PloS one},
volume = {13},
number = {8},
pages = {e0202828},
doi = {10.1371/journal.pone.0202828},
pmid = {30142222},
issn = {1932-6203},
abstract = {Fungi from the widely distributed genus Trichoderma are of great biotechnological interest, being currently used in a vast range of applications. Here, we report that high-molecular weight fraction (HWF) derived from Trichoderma asperelloides ethanolic extract exhibits antibiotic activity against staphylococcal biofilms. The antibacterial and anti-biofilm properties of T. asperelloides extracts were evaluated by well-established assays in Staphylococcus aureus ATCC strains (29213 and 6538) and in one clinical isolate from bovine mastitis. The HWF from T. asperelloides eradicated S. aureus by causing substantial matrix de-structuring and biomass reduction (p < 10-5) at concentrations as low as 2.3 μg mL-1. Additionally, we present ultra-structure analysis by the use of scanning electron microscopy as well as transmission microscopy, which showed that T. asperelloides killed cells through cell wall and membrane disturbance. Remarkably, the HWF from T. asperelloides killed S. aureus and eradicated its biofilms in a greater performance than gentamicin (p < 10-5), a known potent antibiotic against S. aureus. Our results indicate that extract from T. asperelloides may represent a promising candidate for the development of new antibiotics against gram-positive bacteria.},
}
@article {pmid30142035,
year = {2018},
author = {Cepas, V and López, Y and Muñoz, E and Rolo, D and Ardanuy, C and Martí, S and Xercavins, M and Horcajada, JP and Bosch, J and Soto, SM},
title = {Relationship Between Biofilm Formation and Antimicrobial Resistance in Gram-Negative Bacteria.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2018.0027},
pmid = {30142035},
issn = {1931-8448},
abstract = {Gram-negative microorganisms are a significant cause of infection in both community and nosocomial settings. The increase, emergence, and spread of antimicrobial resistance among bacteria are the most important health problems worldwide. One of the mechanisms of resistance used by bacteria is biofilm formation, which is also a mechanism of virulence. This study analyzed the possible relationship between antimicrobial resistance and biofilm formation among isolates of three Gram-negative bacteria species. Several relationships were found between the ability to form biofilm and antimicrobial resistance, being different for each species. Indeed, gentamicin and ceftazidime resistance was related to biofilm formation in Escherichia coli, piperacillin/tazobactam, and colistin in Klebsiella pneumoniae, and ciprofloxacin in Pseudomonas aeruginosa. However, no relationship was observed between global resistance or multidrug-resistance and biofilm formation. In addition, compared with other reported data, the isolates in the present study showed higher rates of antimicrobial resistance. In conclusion, the acquisition of specific antimicrobial resistance can compromise or enhance biofilm formation in several species of Gram-negative bacteria. However, multidrug-resistant isolates do not show a trend to being greater biofilm producers than non-multiresistant isolates.},
}
@article {pmid30141343,
year = {2018},
author = {Roth, SR and Henkel, K and Altenburger, MJ and Auwärter, V and Neukamm, MA},
title = {Multivariate optimization of a method for the determination of fatty acids in dental biofilm by GC-MS.},
journal = {Bioanalysis},
volume = {},
number = {},
pages = {},
doi = {10.4155/bio-2018-0106},
pmid = {30141343},
issn = {1757-6199},
abstract = {AIM: Phospholipid fatty acid methyl ester (FAME) analysis offers a simple option additionally to 16S rRNA sequencing to characterize microbial communities and to monitor changes. A method was established for the characterization of dental plaque via FAME profiles.<br><br>METHODOLOGY: Fatty acids were determined as FAMEs (direct, acidic transesterification) and analyzed by GC-MS using an optimized temperature gradient. The transesterification reaction was optimized using a fractional factorial central composite face-centered design.<br><br>RESULTS: Optimal conditions for the transesterification in methanol/toluene: hydrochloric acid concentration 2% (w/v), reaction time 40 min, temperature 110 °C. Method validation showed satisfactory accuracy, precision and linearity.<br><br>CONCLUSION: The method provides a useful tool to characterize plaque via FAME profiles and was successfully applied to samples from ten subjects demonstrating its applicability.},
}
@article {pmid30140417,
year = {2018},
author = {Mirani, ZA and Fatima, A and Urooj, S and Aziz, M and Khan, MN and Abbas, T},
title = {Relationship of cell surface hydrophobicity with biofilm formation and growth rate: A study on Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli.},
journal = {Iranian journal of basic medical sciences},
volume = {21},
number = {7},
pages = {760-769},
doi = {10.22038/IJBMS.2018.28525.6917},
pmid = {30140417},
issn = {2008-3866},
abstract = {Objectives: This study was designed to determine the relationship of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli isolates in multispecies biofilms and their individual phenotypic characters in biofilm consortia.<br><br>Materials and Methods: The subject isolates were recovered from different food samples and identified on the basis of growth on differential and selective media. Tube methods, Congo-red agar method, and scanning electron microscopy (SEM) were used to study biofilms phenotypes. The hydrophobicity of the strains was evaluated by the adhesion to apolar solvent.<br><br>Results: The results showed that E. coli dominated the pre-biofilm stage. It has been observed that E. coli adopted biofilm life much before S. aureus and P. aeruginosa. However, after adopting biofilm lifestyle, slowly and gradually, P. aeruginosa dominated the consortia and dispersed other stakeholders. The subject isolates of P. aeruginosa produce cis-2-decanoic acid to disperse or inhibit S. aureus and E. coli biofilms. Gas-chromatography and mass spectrometry results showed that cis-2-decanoic was higher in the co-culture condition and increased at late log-phase or at stationary phase. Although majority of S. aureus were unable to compete with P. aeruginosa, however, a minor population competed, survived, and persisted in biofilm consortia as small colony variants. The survivors showed higher expression of sigB and sarA genes. P. aeruginosa showed comparatively higher hydrophobic surface properties.<br><br>Conclusion: Comparative analysis showed that cell surface hydrophobicity, growth rate, and small colony variants (SCVs) are correlated in biofilm consortia of the P. aeruginosa, S. aureus, and E. coli.},
}
@article {pmid30138443,
year = {2018},
author = {Ranfaing, J and Dunyach-Remy, C and Lavigne, JP and Sotto, A},
title = {Propolis potentiates the effect of cranberry (Vaccinium macrocarpon) in reducing the motility and the biofilm formation of uropathogenic Escherichia coli.},
journal = {PloS one},
volume = {13},
number = {8},
pages = {e0202609},
doi = {10.1371/journal.pone.0202609},
pmid = {30138443},
issn = {1932-6203},
abstract = {One strategy to prevent urinary tract infections is the use of natural products such as cranberry (Vaccinium macrocarpon) and propolis. The objective of this study was to evaluate the impact of these products alone and combined on the motility and biofilm formation of a collection of representative uropathogenic Escherichia coli (UPEC). Motility was evaluated by the swarming and swimming capacity of the isolates in presence/absence of cranberry ± propolis. Early and late biofilm formation was observed with the Biofilm Ring test (BioFilm Control) and the crystal violet method. Cranberry alone was seen to have a variable effect on motility and biofilm formation unrelated to bacterial characteristics, but a reduced motility and biofilm formation was observed for all the isolates in the presence of cranberry + propolis. These results suggest that cranberry alone doesn't work on all the E. coli strains and propolis potentiates the effect of cranberry on UPEC, representing a new strategy to prevent recurrent urinary tract infections.},
}
@article {pmid30137191,
year = {2018},
author = {Carvajal, J and Carvajal, M and Chavez, D and Hernandez, G},
title = {Back to Basics: Could the Preoperative Skin Antiseptic Agent Help Prevent Biofilm-Related Capsular Contracture?.},
journal = {Aesthetic surgery journal},
volume = {},
number = {},
pages = {},
doi = {10.1093/asj/sjy216},
pmid = {30137191},
issn = {1527-330X},
abstract = {Background: Capsular contracture (CC) has remained an unresolved issue throughout history. Strong evidence focuses on bacterial biofilm as its main source. A literature review revealed that more than 90% of bacteria found in capsules and implants removed from patients with Baker grade III-IV CC belong to the resident skin microbiome (S. epidermidis, predominant microorganism). The use of an adequate preoperative skin antiseptic may be a critical step to minimize implant contamination and help prevent biofilm-related CC.<br><br>Objectives: To compare the effect of two different antiseptic skin preparations: Povidone-Iodine (PVP-I) versus Chlorhexidine Gluconate (CHG) on CC proportions after primary breast augmentation through a periareolar approach.<br><br>Methods: In June of 2014, The Society for Healthcare Epidemiology of America proposed to use CHG for preoperative skin preparation in the absence of alcohol-containing antiseptic agents as strategy to prevent surgical site infection. The clinical safety committee of a surgical center in Colombia decided to change PVP-I to CHG for surgical site preparation thereafter. Medical records of 63 patients who underwent to primary breast augmentation through a periareolar approach during 2014 were reviewed. In the first six months PVP-I was used in 32 patients, later CHG was employed in 31 patients.<br><br>Results: Pearson's chi-squared test to compare CC proportions between subgroups showed a statistically significant difference. The CC proportion was higher for patients who had antisepsis with PVP-I. CC was absent when CHG was employed.<br><br>Conclusions: CHG as preoperative skin antiseptic for primary breast augmentation surgery was more effective than PVP-I to help prevent biofilm-related CC.},
}
@article {pmid30136892,
year = {2018},
author = {Sorroche, F and Bogino, P and Russo, DM and Zorreguieta, A and Nievas, F and Morales, GM and Hirsch, AM and Giordano, W},
title = {Cell Autoaggregation, Biofilm Formation, and Plant Attachment in a Sinorhizobium meliloti lpsB Mutant.},
journal = {Molecular plant-microbe interactions : MPMI},
volume = {},
number = {},
pages = {MPMI01180004R},
doi = {10.1094/MPMI-01-18-0004-R},
pmid = {30136892},
issn = {0894-0282},
abstract = {Bacterial surface molecules are crucial for the establishment of a successful rhizobia-legume symbiosis, and, in most bacteria, are also critical for adherence properties, surface colonization, and as a barrier for defense. Rhizobial mutants defective in the production of exopolysaccharides (EPSs), lipopolysaccharides (LPSs), or capsular polysaccharides are usually affected in symbiosis with their plant hosts. In the present study, we evaluated the role of the combined effects of LPS and EPS II in cell-to-cell and cell-to-surface interactions in Sinorhizobium meliloti by studying planktonic cell autoaggregation, biofilm formation, and symbiosis with the host plant Medicago sativa. The lpsB mutant, which has a defective core portion of LPS, exhibited a reduction in biofilm formation on abiotic surfaces as well as altered biofilm architecture compared with the wild-type Rm8530 strain. Atomic force microscopy and confocal laser microscopy revealed an increase in polar cell-to-cell interactions in the lpsB mutant, which might account for the biofilm deficiency. However, a certain level of biofilm development was observed in the lpsB strain compared with the EPS II-defective mutant strains. Autoaggregation experiments carried out with LPS and EPS mutant strains showed that both polysaccharides have an impact on the cell-to-cell adhesive interactions of planktonic bacteria. Although the lpsB mutation and the loss of EPS II production strongly stimulated early attachment to alfalfa roots, the number of nodules induced in M. sativa was not increased. Taken together, this work demonstrates that S. meliloti interactions with biotic and abiotic surfaces depend on the interplay between LPS and EPS II.},
}
@article {pmid30135237,
year = {2018},
author = {Klauck, G and Serra, DO and Possling, A and Hengge, R},
title = {Spatial organization of different sigma factor activities and c-di-GMP signalling within the three-dimensional landscape of a bacterial biofilm.},
journal = {Open biology},
volume = {8},
number = {8},
pages = {},
doi = {10.1098/rsob.180066},
pmid = {30135237},
issn = {2046-2441},
abstract = {Bacterial biofilms are large aggregates of cells embedded in an extracellular matrix of self-produced polymers. In macrocolony biofilms of Escherichia coli, this matrix is generated in the upper biofilm layer only and shows a surprisingly complex supracellular architecture. Stratified matrix production follows the vertical nutrient gradient and requires the stationary phase σS (RpoS) subunit of RNA polymerase and the second messenger c-di-GMP. By visualizing global gene expression patterns with a newly designed fingerprint set of Gfp reporter fusions, our study reveals the spatial order of differential sigma factor activities, stringent control of ribosomal gene expression and c-di-GMP signalling in vertically cryosectioned macrocolony biofilms. Long-range physiological stratification shows a duplication of the growth-to-stationary phase pattern that integrates nutrient and oxygen gradients. In addition, distinct short-range heterogeneity occurs within specific biofilm strata and correlates with visually different zones of the refined matrix architecture. These results introduce a new conceptual framework for the control of biofilm formation and demonstrate that the intriguing extracellular matrix architecture, which determines the emergent physiological and biomechanical properties of biofilms, results from the spatial interplay of global gene regulation and microenvironmental conditions. Overall, mature bacterial macrocolony biofilms thus resemble the highly organized tissues of multicellular organisms.},
}
@article {pmid30134244,
year = {2018},
author = {Dostert, M and Belanger, CR and Hancock, REW},
title = {Design and Assessment of Anti-Biofilm Peptides: Steps Toward Clinical Application.},
journal = {Journal of innate immunity},
volume = {},
number = {},
pages = {1-12},
doi = {10.1159/000491497},
pmid = {30134244},
issn = {1662-8128},
abstract = {Highly antibiotic resistant, microbial communities, referred to as biofilms, cause various life-threatening infections in humans. At least two-thirds of all clinical infections are biofilm associated, and antibiotic therapy regularly fails to cure patients. Anti-biofilm peptides represent a promising approach to treat these infections by targeting biofilm-specific characteristics such as highly conserved regulatory mechanisms. They are being considered for clinical application and we discuss here key factors in discovery, design, and application, particularly the implementation of host-mimicking conditions, that are required to enable the successful advancement of potent anti-biofilm peptides from the bench to the clinic.},
}
@article {pmid30131945,
year = {2018},
author = {Midha, A and Janek, K and Niewienda, A and Henklein, P and Guenther, S and Serra, DO and Schlosser, J and Hengge, R and Hartmann, S},
title = {The Intestinal Roundworm Ascaris suum Releases Antimicrobial Factors Which Interfere With Bacterial Growth and Biofilm Formation.},
journal = {Frontiers in cellular and infection microbiology},
volume = {8},
number = {},
pages = {271},
doi = {10.3389/fcimb.2018.00271},
pmid = {30131945},
issn = {2235-2988},
abstract = {Ascariasis is a widespread soil-transmitted helminth infection caused by the intestinal roundworm Ascaris lumbricoides in humans, and the closely related Ascaris suum in pigs. Progress has been made in understanding interactions between helminths and host immune cells, but less is known concerning the interactions of parasitic nematodes and the host microbiota. As the host microbiota represents the direct environment for intestinal helminths and thus a considerable challenge, we studied nematode products, including excretory-secretory products (ESP) and body fluid (BF), of A. suum to determine their antimicrobial activities. Antimicrobial activities against gram-positive and gram-negative bacterial strains were assessed by the radial diffusion assay, while effects on biofilm formation were assessed using the crystal violet static biofilm and macrocolony assays. In addition, bacterial neutralizing activity was studied by an agglutination assay. ESP from different A. suum life stages (in vitro-hatched L3, lung-stage L3, L4, and adult) as well as BF from adult males were analyzed by mass spectrometry. Several proteins and peptides with known and predicted roles in nematode immune defense were detected in ESP and BF samples, including members of A. suum antibacterial factors (ASABF) and cecropin antimicrobial peptide families, glycosyl hydrolase enzymes such as lysozyme, as well as c-type lectin domain-containing proteins. Native, unconcentrated nematode products from intestine-dwelling L4-stage larvae and adults displayed broad-spectrum antibacterial activity. Additionally, adult A. suum ESP interfered with biofilm formation by Escherichia coli, and caused bacterial agglutination. These results indicate that A. suum uses a variety of factors with broad-spectrum antibacterial activity to affirm itself within its microbe-rich environment in the gut.},
}
@article {pmid30131944,
year = {2018},
author = {Subhadra, B and Kim, J and Kim, DH and Woo, K and Oh, MH and Choi, CH},
title = {Local Repressor AcrR Regulates AcrAB Efflux Pump Required for Biofilm Formation and Virulence in Acinetobacter nosocomialis.},
journal = {Frontiers in cellular and infection microbiology},
volume = {8},
number = {},
pages = {270},
doi = {10.3389/fcimb.2018.00270},
pmid = {30131944},
issn = {2235-2988},
abstract = {Multidrug efflux systems contribute to antimicrobial resistance and pathogenicity in bacteria. Here, we report the identification and characterization of a transcriptional regulator AcrR controlling the yet uncharacterized multidrug efflux pump, AcrAB in Acinetobacter nosocomialis. In silico analysis revealed that the homologs of AcrR and AcrAB are reported in the genomes of many other bacterial species. We confirmed that the genes encoding the AcrAB efflux pump, acrA and acrB forms a polycistronic operon which is under the control of acrR gene upstream of acrA. Bioinformatic analysis indicated the presence of AcrR binding motif in the promoter region of acrAB operon and the specific binding of AcrR was confirmed by electrophoretic mobility shift assay (EMSA). The EMSA data showed that AcrR binds to -89 bp upstream of the start codon of acrA. The mRNA expression analysis depicted that the expression of acrA and acrB genes are elevated in the deletion mutant compared to that in the wild type confirming that AcrR acts as a repressor of acrAB operon in A. nosocomialis. The deletion of acrR resulted in increased motility, biofilm/pellicle formation and invasion in A. nosocomialis. We further analyzed the role of AcrR in A. nosocomialis pathogenesis in vivo using murine model and it was shown that acrR mutant is highly virulent inducing severe infection in mouse leading to host death. In addition, the intracellular survival rate of acrR mutant was higher compared to that of wild type. Our data demonstrates that AcrR functions as an important regulator of AcrAB efflux pump and is associated with several phenotypes such as motility, biofilm/pellicle formation and pathogenesis in A. nosocomialis.},
}
@article {pmid30131525,
year = {2018},
author = {Roostaei, J and Zhang, Y and Gopalakrishnan, K and Ochocki, AJ},
title = {Mixotrophic Microalgae Biofilm: A Novel Algae Cultivation Strategy for Improved Productivity and Cost-efficiency of Biofuel Feedstock Production.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {12528},
doi = {10.1038/s41598-018-31016-1},
pmid = {30131525},
issn = {2045-2322},
abstract = {In this work, we studied a novel algae cultivation strategy, mixotrophic microalgae biofilm, to improve the productivity and cost-efficiency of algal biofuel production. In contrast to previous methods, this improved approach can achieve high productivity at low cost by harnessing the benefits of mixotrophic growth's high efficiency, i.e., capable of subsisting on inorganic and organic carbons thus unaffected by limited light, and microalgae biofilm's low harvesting cost. Our results, as one of the first studies of this type, proved that microalgae biofilms under mixotrophic condition exhibited significantly higher productivity and quality of biofuel feedstock: 2-3 times higher of biomass yield, 2-10 times higher of lipid accumulation, and 40-60% lower of ash content when compared to microalgae biofilms under autotrophic condition. In addition, we investigated the impact of cell-surface properties (hydrophobicity and roughness) on the growth activities of microalgae biofilms and found that the productivity of mixotrophic biofilms was significantly correlated with the surface hydrophobicity. Finally, our work demonstrated the applicability of integrating this novel cultivation method with wastewater for maximum efficiency. This study opens a new possibility to solve the long-lasting challenges of algal biofuel feedstock production, i.e., low productivity and high cost of algal cultivation.},
}
@article {pmid30131361,
year = {2018},
author = {Szczesny, M and Beloin, C and Ghigo, JM},
title = {Increased Osmolarity in Biofilm Triggers RcsB-Dependent Lipid A Palmitoylation in Escherichia coli.},
journal = {mBio},
volume = {9},
number = {4},
pages = {},
doi = {10.1128/mBio.01415-18},
pmid = {30131361},
issn = {2150-7511},
abstract = {Biofilms are often described as protective shelters that preserve bacteria from hostile surroundings. However, biofilm bacteria are also exposed to various stresses and need to adjust to the heterogeneous physicochemical conditions prevailing within biofilms. In Gram-negative bacteria, such adaptations can result in modifications of the lipopolysaccharide, a major component of the outer membrane characterized by a highly dynamic structure responding to environmental changes. We previously showed that Gram-negative biofilm bacteria undergo an increase in lipid A palmitoylation mediated by the PagP enzyme, contributing to increased resistance to host defenses. Here we describe a regulatory pathway leading to transcriptional induction of pagP in response to specific conditions created in the biofilm environment. We show that pagP expression is induced via the Rcs envelope stress system independently of the Rcs phosphorelay cascade and that it requires the GadE auxiliary regulator. Moreover, we identify an increase in osmolarity (i.e., ionic stress) as a signal able to induce pagP expression in an RcsB-dependent manner. Consistently, we show that the biofilm is a hyperosmolar environment and that RcsB-dependent pagP induction can be dampened in the presence of an osmoprotectant. These results provide new insights into the adaptive mechanisms of bacterial differentiation in biofilm.IMPORTANCE The development of the dense bacterial communities called biofilms creates a highly heterogeneous environment in which bacteria are subjected to a variety of physicochemical stresses. We investigated the mechanisms of a widespread and biofilm-associated chemical modification of the lipopolysaccharide (LPS), a major component of all Gram-negative bacterial outer membranes. This modification corresponds to the incorporation, mediated by the enzyme PagP, of a palmitate chain into lipid A (palmitoylation) that reduces bacterial recognition by host immune responses. Using biochemical and genetic approaches, we demonstrate that a significant part of biofilm-associated lipid A palmitoylation is triggered upon induction of pagP transcription by the hyperosmolar biofilm environment. pagP induction is regulated by RcsB, the response regulator of the Rcs stress response pathway, and is not observed under planktonic conditions. Our report provides new insights into how physiological adaptations to local biofilm microenvironments can contribute to decreases in susceptibility to antimicrobial agents and host immune defenses.},
}
@article {pmid30131358,
year = {2018},
author = {Uppuluri, P and Acosta Zaldívar, M and Anderson, MZ and Dunn, MJ and Berman, J and Lopez Ribot, JL and Köhler, JR},
title = {Candida albicans Dispersed Cells Are Developmentally Distinct from Biofilm and Planktonic Cells.},
journal = {mBio},
volume = {9},
number = {4},
pages = {},
doi = {10.1128/mBio.01338-18},
pmid = {30131358},
issn = {2150-7511},
abstract = {Candida albicans surface-attached biofilms such as those formed on intravenous catheters with direct access to the bloodstream often serve as a nidus for continuous release of cells capable of initiating new infectious foci. We previously reported that cells dispersed from a biofilm are yeast cells that originate from the top-most hyphal layers of the biofilm. Compared to their planktonic counterparts, these biofilm dispersal yeast cells displayed enhanced virulence-associated characteristics and drug resistance. However, little is known about their molecular properties. To address that issue, in this study we aimed to define the molecular characteristics of these biofilm dispersal cells. We found that the inducer of dispersal, PES1, genetically interacts with the repressor of filamentation, NRG1, in a manner consistent with the definition of dispersed cells as yeast cells. Further, using a flow biofilm model, we performed comprehensive comparative RNA sequencing on freshly dispersed cells in order to identify unique transcriptomic characteristics. Gene expression analysis demonstrated that dispersed cells largely inherit a biofilm-like mRNA profile. Strikingly, however, dispersed cells seemed transcriptionally reprogrammed to acquire nutrients such as zinc and amino acids and to metabolize alternative carbon sources, while their biofilm-associated parent cells did not induce the same high-affinity transporters or express gluconeogenetic genes, despite exposure to the same nutritional signals. Collectively, the findings from this study characterize cell dispersal as an intrinsic step of biofilm development which generates propagules more adept at colonizing distant host sites. This developmental step anticipates the need for virulence-associated gene expression before the cells experience the associated external signals.IMPORTANCECandida albicans surface-attached biofilms serve as a reservoir of cells to perpetuate and expand an infection; cells released from biofilms on catheters have direct access to the bloodstream. Biofilm dispersal yeast cells exhibit enhanced adhesion, invasion, and biofilm formation compared to their planktonic counterparts. Here, we show using transcriptome sequencing (RNA-seq) that dispersed yeast cells are developmentally distinct from the cells in their parent biofilms as well as from planktonic yeast cells. Dispersal cells possess an anticipatory expression pattern that primes them to infect new sites in the host, to survive in nutrient-starved niches, and to invade new sites. These studies identified dispersal cells as a unique proliferative cell type of the biofilm and showed that they could serve as targets for antibiofilm drug development in the future.},
}
@article {pmid30130636,
year = {2018},
author = {Liduino, VS and Lutterbach, MTS and Sérvulo, EFC},
title = {Biofilm activity on corrosion of API 5L X65 steel weld bead.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {172},
number = {},
pages = {43-50},
doi = {10.1016/j.colsurfb.2018.08.026},
pmid = {30130636},
issn = {1873-4367},
abstract = {This work aimed to identify microbial colonization and biocorrosion in welded seam areas of API 5 L X65 carbon steel, since microorganisms are ubiquitous and there is a lack of information on their biological and electrochemical interactions with these structures. In the present study, polished and unpolished welded coupons prepared by shielded metal arc welding were assayed to identify the effect of surface roughness and local changes in the metal microstructure on microbial colonization. Experiments were performed in glass cell vessels with fresh and sterile seawater to establish the presence or absence of microorganisms. For comparison, nonwelded coupons were simultaneously tested as a control. On the 15th day, both polished and unpolished welded coupons and the nonwelded coupons immersed in fresh seawater showed microbial colonization, though the corrosion products were more abundant for the welded coupons. Nevertheless, unpolished welded coupons showed a higher predominance of pitting around the beads than polished coupons. These results suggest that filler material creates conditions more favorable for biofilm development, thus intensifying the localized corrosion on the welds. It can be concluded that adhesion and subsequent biocorrosion are directly influenced by surface roughness, whereas microstructural modifications due to welding interfere little with microbial adhesion, regardless of the greater pit depths compared to those of nonwelded coupons. Additionally, although open circuit potential measurements indicated that metal surfaces are protected when coated with biofilms, pitting corrosion was more pronounced in welded coupons immersed in fresh seawater than in those immersed in seawater without microorganisms. Therefore, the use of open circuit analysis alone is not recommended for biocorrosion monitoring of welded coupons.},
}
@article {pmid30130574,
year = {2018},
author = {Ghorbanzadeh, A and Fekrazad, R and Bahador, A and Ayar, R and Tabatabai, S and Asefi, S},
title = {Evaluation of the antibacterial efficacy of various root canal disinfection methods against Enterococcus faecalis biofilm. An ex-vivo study.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2018.08.010},
pmid = {30130574},
issn = {1873-1597},
abstract = {BACKGROUND: Complete elimination of bacteria and their by-products from the root canal system is very difficult with current techniques. The purpose of this study was to compare the antibacterial efficacy of different disinfection protocols against Enterococcus faecalis (E. faecalis) biofilms.<br><br>METHODS: Seventy-six extracted single-rooted human teeth were selected. Root canal preparation was done by proTaper rotary instruments. The smear layer was removed by 17% EDTA, followed by 5.25% sodium hypochlorite. After sterilization using gamma irradiation, sterilized specimens were inoculated with an E. faecalis suspension, incubated for 4 days and 4 weeks and then randomly divided into two experimental groups (4 days, 4 weeks old biofilms). After the confirmation of biofilm formation with SEM, the specimens in the experimental groups were randomly divided into five experimental subgroups according to the method of disinfection applied, which included: Diode laser irradiation (810 nm, 2 W), Light activated disinfection (LAD), 0.2% Chlorhexidine gluconate (0.2% CHX), 0.2% CHX + LAD and 0.2% CHX + Diode groups.<br><br>RESULTS: Complete biofilm bacterial elimination was not observed in either of the experimental groups. CHX + LAD (0.2%) method exhibited the highest reduction value in biofilm and only Diode alone revealed the lowest in all the root canal portions. Disinfection protocols also showed significantly lower antibacterial efficacy against 4-week old than the 4-day old matured biofilms (P < 0.05).<br><br>CONCLUSION: All the evaluated methods in this study were effective in the relative elimination of the E. faecalis biofilms except diode laser alone. Nevertheless, 0.2% CHX + LAD exhibited significantly higher efficacy in reducing both 4-day and 4-week old biofilms.},
}
@article {pmid30129268,
year = {2018},
author = {Cunha, LDD and Peruzzo, DC and Costa, LA and Pereira, ALP and Benatti, BB},
title = {Effect of a single-tufted toothbrush on the control of dental biofilm in orthodontic patients: A randomized clinical trial.},
journal = {International journal of dental hygiene},
volume = {},
number = {},
pages = {},
doi = {10.1111/idh.12360},
pmid = {30129268},
issn = {1601-5037},
abstract = {OBJECTIVE: To compare the effect of a single-tufted toothbrush combined or not with a conventional toothbrush to control dental biofilm in healthy orthodontic patients.<br><br>MATERIALS AND METHODS: Twenty orthodontic patients were randomly assigned to receive three different treatments: Group 1-conventional toothbrush; Group 2-single-tufted toothbrush and Group 3-combination of single-tufted and conventional toothbrushes. Stained plaque index (SPI), visible plaque index (VPI) and gingival bleeding index (GBI) were recorded. The data were analysed by Kolmogorov-Smirnov test. Wilcoxon test was used for intragroup comparison and Friedman test for the intergroup comparison (α = 5%).<br><br>RESULTS: Intragroup analysis showed that VPI and SPI significantly decreased (P < 0.05) after 72 hour in Group 3. Anterior and posterior teeth did not show any significant statistical differences after 72 hour (P > 0.05), but VPI values in the labial surfaces were different to Group 3 (P < 0.05) in comparison with the other groups after 72 hour. Group 3 showed a statistically significant reduction (P < 0.05) for SPI in the interproximal surfaces when compared with Group 1.<br><br>CONCLUSION: The combination of single-tufted and conventional toothbrushes was effective for controlling dental biofilm formation in orthodontic patients.},
}
@article {pmid30128583,
year = {2018},
author = {Liu, Y and Shi, H and Wang, Z and Huang, X and Zhang, X},
title = {Pleiotropic control of antibiotic biosynthesis, flagellar operon expression, biofilm formation, and carbon source utilization by RpoN in Pseudomonas protegens H78.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-018-9282-0},
pmid = {30128583},
issn = {1432-0614},
support = {31470196//National Natural Science Foundation of China/ ; 31270083//National Natural Science Foundation of China/ ; },
abstract = {The rhizobacterium Pseudomonas protegens H78 biosynthesizes a number of antibiotic compounds, including pyoluteorin, 2,4-diacetylphloroglucinol, and pyrrolnitrin. Here, we investigated the global regulatory function of the nitrogen metabolism-related sigma factor RpoN in P. protegens H78 through RNA-seq and phenotypic analysis. During the mid- to late-log growth phase, transcriptomic profiling revealed that 562 genes were significantly upregulated, and 502 genes were downregulated by at least twofold at the RNA level in the rpoN deletion mutant in comparison with the wild-type strain H78. With respect to antibiotics, Plt biosynthesis and the expression of its operon were positively regulated, while Prn biosynthesis and the expression of its operon were negatively regulated by RpoN. RpoN is responsible for the global activation of operons involved in flagellar biogenesis and assembly, biofilm formation, and bacterial mobility. In contrast, RpoN was shown to negatively control a number of secretion system operons including one type VI secretion system operon (H1-T6SS), two pilus biogenesis operons (Flp/Tad-T4b pili and Csu-T1 pili), and one polysaccharide biosynthetic operon (psl). In addition, two operons that are involved in mannitol and inositol utilization are under the positive regulation of RpoN. Consistent with this result, the ability of H78 to utilize mannitol or inositol as a sole carbon source is positively influenced by RpoN. Taken together, the RpoN-mediated global regulation is mainly involved in flagellar biogenesis and assembly, bacterial mobility, biofilm formation, antibiotic biosynthesis, secretion systems, and carbon utilization in P. protegens H78.},
}
@article {pmid30128582,
year = {2018},
author = {Ontiveros-Valencia, A and Zhou, C and Zhao, HP and Krajmalnik-Brown, R and Tang, Y and Rittmann, BE},
title = {Managing microbial communities in membrane biofilm reactors.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-018-9293-x},
pmid = {30128582},
issn = {1432-0614},
abstract = {Membrane biofilm reactors (MBfRs) deliver gaseous substrates to biofilms that develop on the outside of gas-transfer membranes. When an MBfR delivers electron donors hydrogen (H2) or methane (CH4), a wide range of oxidized contaminants can be reduced as electron acceptors, e.g., nitrate, perchlorate, selenate, and trichloroethene. When O2 is delivered as an electron acceptor, reduced contaminants can be oxidized, e.g., benzene, toluene, and surfactants. The MBfR's biofilm often harbors a complex microbial community; failure to control the growth of undesirable microorganisms can result in poor performance. Fortunately, the community's structure and function can be managed using a set of design and operation features as follows: gas pressure, membrane type, and surface loadings. Proper selection of these features ensures that the best microbial community is selected and sustained. Successful design and operation of an MBfR depends on a holistic understanding of the microbial community's structure and function. This involves integrating performance data with omics results, such as with stoichiometric and kinetic modeling.},
}
@article {pmid30128579,
year = {2018},
author = {Zhou, JW and Hou, B and Liu, GY and Jiang, H and Sun, B and Wang, ZN and Shi, RF and Xu, Y and Wang, R and Jia, AQ},
title = {Attenuation of Pseudomonas aeruginosa biofilm by hordenine: a combinatorial study with aminoglycoside antibiotics.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-018-9315-8},
pmid = {30128579},
issn = {1432-0614},
support = {2017YFD0201401//the National Key Research and Development Program of China/ ; 41766006//National Natural Science Foundation of China/ ; BK20170859//Natural Science Foundation of Jiangsu Province/ ; 201608052//Science and Technology Development Program of Modern Agriculture/ ; 30916011307//Six Talent Peaks Project in Jiangsu Province, and Fundamental Research Funds for the Central Universities/ ; },
abstract = {Pseudomonas aeruginosa is a ubiquitous pathogen that is the leading cause of chronic infections. Bacterial biofilm formation facilitates CF development and restricts the anti-bacterial potential of many current antibiotics. The capacity of P. aeruginosa to form biofilms and resist antibiotics is closely correlated with quorum sensing (QS). Disrupting QS by QS inhibitors is a promising strategy for treating chronic infections. Here, we evaluated the effect of hordenine, a recently characterized QS inhibitor, on the susceptibility of aminoglycoside antibiotics against P. aeruginosa biofilms. Hordenine significantly enhanced the susceptibility of aminoglycoside antibiotics tobramycin, gentamycin, and amikacin against P. aeruginosa PAO1 biofilm formation. Combinations of hordenine and aminoglycoside antibiotics showed potent efficiency in disrupting the preformed biofilms of P. aeruginosa. Microscopic observations showed flat, scattered, and unstructured biofilm architecture after treatment with hordenine. Mechanistic study further revealed that hordenine treatment led to the downregulation of genes involved in QS and biofilm formation. Thus, our results suggest that hordenine has the potential to function as an antibiotic accelerant in treating P. aeruginosa infections.},
}
@article {pmid30126038,
year = {2018},
author = {Korsch, M and Marten, SM and Walther, W and Vital, M and Pieper, DH and Dötsch, A},
title = {Impact of dental cement on the peri-implant biofilm-microbial comparison of two different cements in an in vivo observational study.},
journal = {Clinical implant dentistry and related research},
volume = {},
number = {},
pages = {},
doi = {10.1111/cid.12650},
pmid = {30126038},
issn = {1708-8208},
abstract = {BACKGROUND: The type of cement used in cemented fixed implant-supported restorations influences formation of undetected excess cement and composition of the peri-implant biofilm. Excess cement and dysbiosis of the biofilm involve the risk of peri-implant inflammation.<br><br>PURPOSE: The aim of the study was to investigate the impact of two different cements on the peri-implant biofilm and inflammation.<br><br>MATERIALS AND METHODS: In an observational study, the suprastructures of 34 patients with cemented fixed implant-supported restorations were revised. In 20 patients, a methacrylate cement (Premier Implant cement [PIC]) and in 14 patients, a zinc oxide eugenol cement (Temp Bond [TB]) were used. After revision, TB was used for recementation. During revision and follow-up after 1 year, microbial samples were obtained.<br><br>RESULTS: Excess cement was found in 12 (60%) of the 20 patients with PIC. Suppuration was observed in two (25%) implants with PIC without excess cement (PIC-) and in all 12 (100%) implants with PIC and excess cement (PIC+). Implants cemented with TB had neither excess cement nor suppuration. The taxonomic analysis of the microbial samples revealed an accumulation of periodontal pathogens in the PIC patients independent of the presence of excess cement. Significantly, fewer oral pathogens occurred in patients with TB compared to patients with PIC. TB was used in all cases (PIC and TB) for recementation. In the follow-up check, suppuration was not found around any of the implants with PIC-, only around one implant with PIC+ and around one implant with TB. Bacterial species associated with severe periodontal infections that were abundant in PIC- and PIC+ samples before the revision were reduced after 1 year to levels found in the TB samples.<br><br>CONCLUSIONS: The revision and recementation with TB had a positive effect on the peri-implant biofilm in cases with PIC. The cementation of suprastructures on implants with TB is an alternative method to be considered.},
}
@article {pmid30124817,
year = {2018},
author = {Cirri, E and Vyverman, W and Pohnert, G},
title = {Biofilm interactions - bacteria modulate sexual reproduction success of the diatom Seminavis robusta.},
journal = {FEMS microbiology ecology},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsec/fiy161},
pmid = {30124817},
issn = {1574-6941},
abstract = {Marine biofilms are complex multi-species communities where chemical signaling regulates a substantial share of interactions. The involved natural products represent targets for competition strategies by signal interference. Diatoms, that often dominate biofilms, rely on a complex pheromone system during sexual reproduction, involving synchronizing and attracting metabolites. The present study addresses the effect of bacteria on sexual reproduction of the model pennate diatom Seminavis robusta. We observe that sexual reproduction is most efficient under axenic conditions. Bacteria isolated form field collected biofilms modulate sexual reproduction in the algae. A species-specific effect on the diatom mating efficiency could be observed, with Maribacter sp. and Marinobacter sp. significantly reducing the sexual reproduction rate. Spent medium from these bacteria has the same effect, demonstrating that chemically mediated cross kingdom interactions take place. In contrast, Roseovarius sp. increased the proportion of sexual cells. We further observed a lower concentration of the diatom attraction pheromone diproline in the presence of bacteria compared to axenic conditions. In agreement, the Seminavis-associated bacterial community as well as isolated bacterial strains degraded the pheromone over time. Our results highlight that the pheromone system of diatoms is subject to interference strategies of the associated bacterial community by modulation of the signal landscape.},
}
@article {pmid30124812,
year = {2018},
author = {Kavazos, CRJ and Huggett, MJ and Mueller, U and Horwitz, P},
title = {Bacterial and ciliate biofilm community structure at different spatial levels of a salt lake meta-community.},
journal = {FEMS microbiology ecology},
volume = {94},
number = {10},
pages = {},
doi = {10.1093/femsec/fiy148},
pmid = {30124812},
issn = {1574-6941},
abstract = {Meta-communities are assembled along an ecological scale that determines local and regional diversity. Spatial patterns have been detected in planktonic bacterial communities at distances <20 m, but little is known about the occurrence of similar variation for other microbial groups and changes in microbial meta-community assembly at different levels of a meta-community. To examine this variation, the biofilm of eight saline ponds were used to investigate processes shaping diversity within ponds (β) and between ponds (δ). Bacterial and ciliate communities were assessed using ARISA and T-RFLP respectively, while diversity partitioning methods were used to examine the importance of taxonomic turnover and variation partitioning was used to distinguish spatial from environmental determinants. The results show that turnover is important for determining β- and δ-diversity of biofilms. Spatial factors are important drivers of bacterial β-diversity but were unimportant for ciliate β-diversity. Environmental variation was a strong determinant of bacterial and ciliate δ-diversity, suggesting sorting processes are important for assembling pond communities. Determinants of diversity in bacteria are not universal for ciliates, suggesting higher functional redundancy of bacteria or the greater niche breadth of ciliates may be important in discriminating assembly processes between the two organisms.},
}
@article {pmid30120959,
year = {2018},
author = {Bhatt, S and Mehta, P and Chen, C and Schneider, CL and White, LN and Chen, HL and Kong, MG},
title = {Efficacy of low-temperature plasma activated gas disinfection against biofilm on contaminated GI endoscope channels.},
journal = {Gastrointestinal endoscopy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.gie.2018.08.009},
pmid = {30120959},
issn = {1097-6779},
abstract = {BACKGROUND: It has been increasingly recognized that the safety of gastrointestinal endoscopes needs to be improved by addressing the small margin of safety of high-level disinfectants (HLD), and the failure of HLD to clear multi-drug resistant organisms and biofilms. There is also an unmet need for effective low-temperature sterilization techniques that have a clear pathway for FDA clearance. Here, we report the results of our investigation of a novel argon plasma-activated gas (PAG) for disinfection and potentially sterilization of biofilm-contaminated endoscopic channels.<br><br>METHODS: Test PTFE channel segments were contaminated with 4-, 24- and 48-hour luminal biofilms of MRSA, P aeruginosa or E coli and were treated by PAG flowing for up to 9 minutes. After PAG treatment, inactivation and dispersal of luminal bacterial biofilms as well as their regrowth in 48 hours were evaluated. Reactive species induced by PAG were measured with colorimetric probes and electron spin resonance spectrometry. Surface morphology and elemental composition of PAG-treated channel material were analyzed with scanning electron microscopy.<br><br>RESULTS: PAG treatment for 9 minutes led to more than 8 log reduction of viable cells and dispersal of 24- and 48-hour luminal biofilms of all 3 bacteria and to suppression of their regrowth, whereas it resulted in little morphological abnormalities in channel material. Ozone concentration of PAG fell to below 0.01 ppm within 30 seconds of switching off the plasma. PAG-treated deionized water was acidified with numerous types of reactive species, each with a concentration some 3 orders of magnitude or more below its bacterial inhibition concentration.<br><br>CONCLUSIONS: PAG is capable of effectively and rapidly disinfecting luminal bacterial biofilms and offers an alternative to the step of HLD and/or ethylene oxide in the endoscope reprocessing procedure with safety to personnel and environment.},
}
@article {pmid30119039,
year = {2018},
author = {Ismail, Z and Aziz, MMA and Mahmood, NAN and Ismail, S and Umor, NA and Faua'ad Syed Muhammad, SA},
title = {Optimisation of a modified submerged bed biofilm reactor for biological oleochemical wastewater treatment.},
journal = {Journal of environmental management},
volume = {226},
number = {},
pages = {156-162},
doi = {10.1016/j.jenvman.2018.08.003},
pmid = {30119039},
issn = {1095-8630},
abstract = {Oleochemicals industry effluence mainly contains a high chemical oxygen demand (COD) in a range of 6000-20,000 ppm. An effective biological wastewater treatment process must be carried out before wastewater is discharged into the environment. In this study, a submerged bed biofilm reactor (SBBR) was adapted to the biological oleochemical wastewater treatment plant observed in the present study. The effect of wastewater flow rate (100-300 mL/min), Cosmoball® percentage in the SBBR system (25-75%), and percentage of activated sludge (0-50%) were investigated in terms of COD reduction. The Box-Behnken design was used for response surface methodology (RSM) and to create a set of 18 experimental runs, which was needed for optimising the biological oleochemical wastewater treatment. A quadratic polynomial model with estimated coefficients was developed to describe COD reduction patterns. The analysis of variance (ANOVA) shows that the wastewater flow rate was the most effective factor in reducing COD, followed by activated sludge percentage and Cosmoball® carrier percentage. Under the optimum conditions (i.e., a wastewater flow rate of 103.25 mL/min a Cosmoball® carrier percentage of 71.94%, and an activated sludge percentage of 40.50%) a COD reduction of 98% was achieved. Thus, under optimum conditions, as suggested by the BBD, SBBR systems can be used as a viable means of biological wastewater treatment in the oleochemicals industry.},
}
@article {pmid30118807,
year = {2018},
author = {Tavafi, H and Ali, AA and Ghadam, P and Gharavi, S},
title = {Screening, cloning and expression of a novel alginate lyase gene from P. aeruginosa TAG 48 and its antibiofilm effects on P. aeruginosa biofilm.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2018.08.018},
pmid = {30118807},
issn = {1096-1208},
abstract = {BACKGROUND: Pseudomonas aeruginosa is an opportunistic pathogen and utilizes several virulence factors for pathogenesis. One of the most important factors is alginate, found in the biofilm which enables P. aeruginosa to establish chronic lung infections.<br><br>MATERIALS AND METHODS: In this study, 25 clinical alginate-degrading isolates were selected. Biochemical and molecular approach were carried out to identify the isolates by 16S rDNA gene amplification. Growth conditions and enzyme production were the criteria for selection. Since the main objective of the project was the production and characterization of alginate lyase and its effect on biofilm elimination, the P. aeruginosa sp.TAG48 alginate lyase-encoding gene was isolated, cloned, sequenced and expressed in E.coli DH5α. The resultant enzyme was purified by affinity chromatography. Ciprofloxacin, tobramycin and cefixime were also used to test the effectiveness of these antibiotics on P. aeruginosa biofilm by minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC). The synergistic effects of these antibiotics and the recombinant alginate lyase on biofilm were evaluated.<br><br>RESULTS: Results indicate that the addition of alginate (0.2%-0.8%) and NaCl (0.2-0.5 M) to the medium significantly increases cell growth followed by higher enzyme production (p≤ 0.05). Moreover, substrate specificity of alginate lyase produced by P. aeruginosa sp.TAG48 shows the enzyme is capable of degrading both polyM and polyG alginate and acts bifunctionally. Results from the antimicrobial characteristics of the antibiotics and the enzyme have shown MBIC for ciprofloxacin, tobramycin, cefixime and enzyme in the following concentrations 4, 32, 256 and 18.75 μg/ml, and MBEC: 32, 128, ≥ 512 and 37.5 μg/ml, respectively. The study of synergism between the antibiotics and the enzyme to prevent growth and eradication of P. aeruginosa sp.TAG48 biofilm shows that alginate lyase exhibits synergy with tobramycin and cefixime but not with ciprofloxacin.<br><br>CONCLUSION: The results indicate that the use of purified novel alginate lyase with antibiotics could be a beneficial alternative for the treatment of P. aeruginosa infections. Elucidation of mechanisms involved in antibiotic resistance and the role of biofilm structure could assist physicians select optimum treatment regimen.},
}
@article {pmid30118805,
year = {2018},
author = {Sun, X and Lin, ZW and Hu, XX and Yao, WM and Bai, B and Wang, HY and Li, DY and Chen, Z and Cheng, H and Pan, WG and Deng, MG and Xu, GJ and Tu, HP and Chen, JW and Deng, QW and Yu, ZJ and Zheng, JX},
title = {Biofilm formation in erythromycin-resistant Staphylococcus aureus and the relationship with antimicrobial susceptibility and molecular characteristics.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2018.08.021},
pmid = {30118805},
issn = {1096-1208},
abstract = {PURPOSE: In this study, we aimed to investigate biofilm formation characteristics in clinical Staphylococcus aureus (S. aureus) isolates with erythromycin (ERY) resistance from China and further analyze their correlations with antimicrobial susceptibility and molecular characteristics.<br><br>METHOD: ology A total of 276 clinical isolates of ERY-resistant S. aureus, including 142 methicillin-resistant S. aureus (MRSA) strains and 134 methicillin-susceptible S. aureus (MSSA) strains, were retrospectively collected in China. Biofilms were determined by crystal violet staining and ERY resistance genes (ermA, ermB and ermC) were detected by polymerase chain reaction. Inducible clindamycin resistance was examined by D test and multilocus sequence typing, and clonal complexes (CCs) based on housekeeping genes were further determined.<br><br>RESULTS: The frequency of biofilm formation among ERY-resistant S. aureus was 40.9% (113/276) in total and no significant difference was found for the frequency of biofilm formation between ERY-resistant MRSA and ERY-resistant MSSA (44.4% vs 37.3%, P > 0.05). In ERY-resistant MRSA isolates, the frequency of biofilm formation in ermA-positive, gentamicin-resistant and ciprofloxacin-resistant isolates was higher than that in ermA-negative, gentamicin-sensitive and ciprofloxacin-sensitive isolates, respectively (63.9% vs 23.6%, P < 0.01; 60.3% vs 27.5%, P < 0.01; 65.2% vs 26.3%, P < 0.01). In addition, tetracycline resistance facilitated biofilm formation in both ERY-resistant MRSA and MSSA and the frequency of biofilm formation in CC239- or CC7S. aureus isolates with ERY resistance was significantly higher compared with that in CC59S. aureus (both P < 0.01).<br><br>CONCLUSION: The ermA gene, and gentamicin, ciprofloxacin and tetracycline resistance facilitate biofilm formation in ERY-resistant MRSA isolates and, moreover, ERY-resistant S. aureus isolates with positive biofilm formation exhibited clonality clustering regarding CC239 and CC7.},
}
@article {pmid30116222,
year = {2018},
author = {Servetas, SL and Doster, RS and Kim, A and Windham, IH and Cha, JH and Gaddy, JA and Merrell, DS},
title = {ArsRS-Dependent Regulation of homB Contributes to Helicobacter pylori Biofilm Formation.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1497},
doi = {10.3389/fmicb.2018.01497},
pmid = {30116222},
issn = {1664-302X},
abstract = {One elusive area in the Helicobacter pylori field is an understanding of why some infections result in gastric cancer, yet others persist asymptomatically for the life-span of the individual. Even before the genomic era, the high level of intraspecies diversity of H. pylori was well recognized and became an intriguing area of investigation with respect to disease progression. Of interest in this regard is the unique repertoire of over 60 outer membrane proteins (OMPs), several of which have been associated with disease outcome. Of these OMPs, the association between HomB and disease outcome varies based on the population being studied. While the molecular roles for some of the disease-associated OMPs have been evaluated, little is known about the role that HomB plays in the H. pylori lifecycle. Thus, herein we investigated homB expression, regulation, and contribution to biofilm formation. We found that in H. pylori strain G27, homB was expressed at a relatively low level until stationary phase. Furthermore, homB expression was suppressed at low pH in an ArsRS-dependent manner; mutation of arsRS resulted in increased homB transcript at all tested time-points. ArsRS regulation of homB appeared to be direct as purified ArsR was able to specifically bind to the homB promoter. This regulation, combined with our previous finding that ArsRS mutations lead to enhanced biofilm formation, led us to test the hypothesis that homB contributes to biofilm formation by H. pylori. Indeed, subsequent biofilm analysis using a crystal-violet quantification assay and scanning electron microscopy (SEM) revealed that loss of homB from hyper-biofilm forming strains resulted in reversion to a biofilm phenotype that mimicked wild-type. Furthermore, expression of homB in trans from a promoter that negated ArsRS regulation led to enhanced biofilm formation even in strains in which the chromosomal copy of homB had been deleted. Thus, homB is necessary for hyper-biofilm formation of ArsRS mutant strains and aberrant regulation of this gene is sufficient to induce a hyper-biofilm phenotype. In summary, these data suggest that the ArsRS-dependent regulation of OMPs such as HomB may be one mechanism by which ArsRS dictates biofilm development in a pH responsive manner.},
}
@article {pmid30116152,
year = {2018},
author = {Tan, Q and Ai, Q and Xu, Q and Li, F and Yu, J},
title = {Polymorphonuclear Leukocytes or Hydrogen Peroxide Enhance Biofilm Development of Mucoid Pseudomonas aeruginosa.},
journal = {Mediators of inflammation},
volume = {2018},
number = {},
pages = {8151362},
doi = {10.1155/2018/8151362},
pmid = {30116152},
issn = {1466-1861},
abstract = {Pseudomonas aeruginosa is an opportunistic pathogenic bacterium involved in many human infections, including pneumonia, diabetic foot ulcers, and ventilator-associated pneumonia. P. aeruginosa cells usually undergo mucoid conversion during chronic lung infection in patients with cystic fibrosis (CF) and resist destruction by polymorphonuclear leukocytes (PMNs), which release free oxygen radicals (ROS), such as H2O2. PMNs are the main leucocytes in the CF sputum of patients who are infected with P. aeruginosa, which usually forms biofilms. Here, we report that PMNs or H2O2 can promote biofilm formation by mucoid P. aeruginosa FRD1 with the use of the hanging-peg method. The mucoid strain infecting CF patients overproduces alginate. In this study, PMNs and H2O2 promoted alginate production, and biofilms treated with PMNs or H2O2 exhibited higher expression of alginate genes. Additionally, PMNs increased the activity of GDP-mannose dehydrogenase, which is the key enzyme in alginate biosynthesis. Our results demonstrate that PMNs or H2O2 can enhance mucoid P. aeruginosa biofilms.},
}
@article {pmid30116127,
year = {2018},
author = {Bayazian, G and Sayyahfar, S and Safdarian, M and Kalantari, F},
title = {Is there any association between adenoid biofilm and upper airway infections in pediatric patients?.},
journal = {Turk pediatri arsivi},
volume = {53},
number = {2},
pages = {71-77},
doi = {10.5152/TurkPediatriArs.2018.6151},
pmid = {30116127},
issn = {1306-0015},
abstract = {Aim: To evaluate the association of the presence and extent of adenoid biofilms and the frequency of upper airway infections in children with upper airway obstruction.<br><br>Material and Methods: This cross-sectional study was conducted from October 2014 to December 2015 on pediatric patients who were candidates for adenoidectomy due to obstructive sleep apnea. After removal of the adenoid tissue and fixation in 2.5% glutaraldehyde, the samples were sent to the electron microscopy unit. The extent of biofilm formation was examined using environmental scanning electron microscopy. These results were then confirmed using image analysis software.<br><br>Results: Fifty-seven children with a mean age of 7.31 (±2.65) years were included in the study. Forty-three (75.4%) were male and 14 (24.6%) were female. The average number of upper airway infections during the last 12 months before adenoidectomy was 10.01 (±5.38). Biofilm structures were detected in all (100%) samples. As the main outcome, the extent of biofilm grading exhibited a statistically significant correlation with the frequency of upper airway infections (p<0.001). There was no significant correlation between sex and adenoid size with the biofilm extent.<br><br>Conclusion: The present study showed that the extent of adenoid biofilm had a significant relationship with the frequency of upper airway infection rate. It seems that the presence of a biofilm on the adenoid surface as a reservoir for microorganisms could cause chronic inflammation.},
}
@article {pmid30114632,
year = {2018},
author = {Asri, M and El Ghachtouli, N and Elabed, S and Ibnsouda Koraichi, S and Elabed, A and Silva, B and Tavares, T},
title = {Wicherhamomyces anomalus biofilm supported on wood husk for chromium wastewater treatment.},
journal = {Journal of hazardous materials},
volume = {359},
number = {},
pages = {554-562},
doi = {10.1016/j.jhazmat.2018.05.050},
pmid = {30114632},
issn = {1873-3336},
abstract = {A Wickeramomyces anomalus biofilm supported on wood husk was used to remediate water bodies contaminated with chromium (Cr), in batch and open systems. The favorable adhesion ability of the chromium-resistant yeast strain on the wood husk was predicted by XDLVO theory and confirmed by environmental scanning electronic microscopy. The chromium decontamination was then optimized in a batch mode using a central composite design (CCD). Analysis of variance (ANOVA) showed a high coefficient of determination (R2) value of 0.93-0.91 for Cr(VI) and total Cr removal, respectively, ensuring a satisfactory fitting of the second-order regression model to the experimental data. In batch system, the concentration of biomass exhibited the minimal effect on the process. An acidic pH of 3.72 and 5.48, an initial chromium concentration of 10 and 16.91 mg/L and a support dose of 6.95 and 8.20 g/L were optimal for Cr(VI) and total Cr removal, respectively. The breakthrough curves were determined in open system for different initial chromium concentrations. The study of glucose concentration effect on the yeast extracellular polymeric substances (EPS) production showed that a medium exempt of glucose allowed maximal EPS production and minimal chromium removal efficiency, while 20 g/L glucose concentration of presented the optimal condition for chromium removal.},
}
@article {pmid30111629,
year = {2018},
author = {Kiedrowski, MR and Gaston, JR and Kocak, BR and Coburn, SL and Lee, S and Pilewski, JM and Myerburg, MM and Bomberger, JM},
title = {Staphylococcus aureus Biofilm Growth on Cystic Fibrosis Airway Epithelial Cells Is Enhanced during Respiratory Syncytial Virus Coinfection.},
journal = {mSphere},
volume = {3},
number = {4},
pages = {},
doi = {10.1128/mSphere.00341-18},
pmid = {30111629},
issn = {2379-5042},
abstract = {Staphylococcus aureus is a major cause of chronic respiratory infection in patients with cystic fibrosis (CF). We recently showed that Pseudomonas aeruginosa exhibits enhanced biofilm formation during respiratory syncytial virus (RSV) coinfection on human CF airway epithelial cells (AECs). The impact of respiratory viruses on other bacterial pathogens during polymicrobial infections in CF remains largely unknown. To investigate if S. aureus biofilm growth in the CF airways is impacted by virus coinfection, we evaluated S. aureus growth on CF AECs. Initial studies showed an increase in S. aureus growth over 24 h, and microscopy revealed biofilm-like clusters of bacteria on CF AECs. Biofilm growth was enhanced when CF AECs were coinfected with RSV, and this observation was confirmed with S. aureus CF clinical isolates. Apical conditioned medium from RSV-infected cells promoted S. aureus biofilms in the absence of the host epithelium, suggesting that a secreted factor produced during virus infection benefits S. aureus biofilms. Exogenous iron addition did not significantly alter biofilm formation, suggesting that it is not likely the secreted factor. We further characterized S. aureus-RSV coinfection in our model using dual host-pathogen RNA sequencing, allowing us to observe specific contributions of S. aureus and RSV to the host response during coinfection. Using the dual host-pathogen RNA sequencing approach, we observed increased availability of nutrients from the host and upregulation of S. aureus genes involved in growth, protein translation and export, and amino acid metabolism during RSV coinfection.IMPORTANCE The airways of individuals with cystic fibrosis (CF) are commonly chronically infected, and Staphylococcus aureus is the dominant bacterial respiratory pathogen in CF children. CF patients also experience frequent respiratory virus infections, and it has been hypothesized that virus coinfection increases the severity of S. aureus lung infections in CF. We investigated the relationship between S. aureus and the CF airway epithelium and observed that coinfection with respiratory syncytial virus (RSV) enhances S. aureus biofilm growth. However, iron, which was previously found to be a significant factor influencing Pseudomonas aeruginosa biofilms during virus coinfection, plays a minor role in S. aureus coinfections. Transcriptomic analyses provided new insight into how bacterial and viral pathogens alter host defense and suggest potential pathways by which dampening of host responses to one pathogen may favor persistence of another in the CF airways, highlighting complex interactions occurring between bacteria, viruses, and the host during polymicrobial infections.},
}
@article {pmid30111175,
year = {2018},
author = {Wu, Y and Shi, YG and Zeng, LY and Pan, Y and Huang, XY and Bian, LQ and Zhu, YJ and Zhang, RR and Zhang, J},
title = {Evaluation of antibacterial and anti-biofilm properties of kojic acid against five food-related bacteria and related subcellular mechanisms of bacterial inactivation.},
journal = {Food science and technology international = Ciencia y tecnologia de los alimentos internacional},
volume = {},
number = {},
pages = {1082013218793075},
doi = {10.1177/1082013218793075},
pmid = {30111175},
issn = {1532-1738},
abstract = {Although the antimicrobial properties of kojic acid have been recognized, the subcellular mechanism of bacterial inactivation caused by it has never been clearly elucidated. In the present study, the antibacterial and anti-biofilm activity of kojic acid was evaluated against five foodborne pathogens including Listeria monocytogenes, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Salmonella typhimurium. The antibacterial activity was determined by minimum inhibitory concentration, minimum bactericidal concentration, and the time-kill assay. Among them, the susceptibility of Escherichia coli was significant with the lowest minimum inhibitory concentration and minimum bactericidal concentration values of 10 and 20 mM, respectively. Subcellular mechanism of bacterial inactivation related to kojic acid was revealed through comprehensive factors including cell morphology, membrane permeability, K+ leakage, zeta potential, intracellular enzyme, and DNA assay. Results demonstrated that bacterial inactivation caused by kojic acid, especially for Gram-negative bacteria, was primarily induced by the pronounced damage to the cell membrane integrity. Leakage of intracellular enzyme to the supernatants implied that the cell membrane permeability was compromised. Consequently, the release of K+ from the cytosol leads to the alterations of the zeta potential of cells, which would disturb the subcellular localization of some proteins and thereby cause the bacterial inactivation. The free -CH2OH group at the C-2 of kojic acid could play more significant role in the antimicrobial performance of kojic acid against Gram-negative bacteria. Moreover, remarkable interaction with DNA was also observed. Kojic acid at sub-minimum inhibitory concentration inhibited biofilm formation by these bacteria.},
}
@article {pmid30108790,
year = {2017},
author = {Garrison, AT and Abouelhassan, Y and Yang, H and Yousaf, HH and Nguyen, TJ and Huigens Iii, RW},
title = {Microwave-enhanced Friedländer synthesis for the rapid assembly of halogenated quinolines with antibacterial and biofilm eradication activities against drug resistant and tolerant bacteria.},
journal = {MedChemComm},
volume = {8},
number = {4},
pages = {720-724},
doi = {10.1039/c6md00381h},
pmid = {30108790},
issn = {2040-2503},
abstract = {Herein, we disclose the development of a catalyst- and protecting-group-free microwave-enhanced Friedländer synthesis which permits the single-step, convergent assembly of diverse 8-hydroxyquinolines with greatly improved reaction yields over traditional oil bath heating (increased from 34% to 72%). This rapid synthesis permitted the discovery of novel biofilm-eradicating halogenated quinolines (MBECs = 1.0-23.5 μM) active against MRSA, MRSE, and VRE. These small molecules exhibit activity through mechanisms independent of membrane lysis, further demonstrating their potential as a clinically useful treatment option against persistent biofilm-associated infections.},
}
@article {pmid30109972,
year = {2018},
author = {Luque-Sastre, L and Fox, EM and Jordan, K and Fanning, S},
title = {A Comparative Study of the Susceptibility of Listeria Species to Sanitizer Treatments When Grown under Planktonic and Biofilm Conditions.},
journal = {Journal of food protection},
volume = {},
number = {},
pages = {1481-1490},
doi = {10.4315/0362-028X.JFP-17-466},
pmid = {30109972},
issn = {1944-9097},
abstract = {Listeria species are ubiquitous in nature and can adapt to survive in a variety of niches, including food processing environments. Listeria species that colonize these environments may also have the potential to persist. Food safety strategies designed to manage these niches include regular cleaning and disinfection with proven sanitizers containing biocide-active compounds. Typically, these sanitizers are effective against bacteria growing under planktonic conditions, but their efficacy may be compromised when bacteria are contained in biofilms. The susceptibility of persistent Listeria isolates, i.e., those capable of forming biofilms, to a selection of sanitizers was investigated. A quaternary ammonium compound-based sanitizer was the biocide most effective against planktonic bacteria, with a MIC of 0.0015 to 0.006%. In contrast, ethanol-based sanitizers were the least effective. Although, no triclosan tolerance was observed for planktonic Listeria isolates, triclosan was the only biocide that resulted in a significant biomass reduction. Differences between Listeria species were observed; L. monocytogenes and L. welshimeri biofilms were more tolerant to quaternary ammonium compound-based sanitizers than were L. innocua biofilms. These findings extend our understanding of the application of commonly used sanitizers in the food industry and the efficacy of these sanitizers against Listeria species and their associated biofilms.},
}
@article {pmid30109118,
year = {2018},
author = {Gomez-Carretero, S and Libberton, B and Svennersten, K and Persson, K and Jager, E and Berggren, M and Rhen, M and Richter-Dahlfors, A},
title = {Erratum: Author Correction: Redox-active conducting polymers modulate Salmonella biofilm formation by controlling availability of electron acceptors.},
journal = {NPJ biofilms and microbiomes},
volume = {4},
number = {},
pages = {19},
doi = {10.1038/s41522-018-0061-6},
pmid = {30109118},
issn = {2055-5008},
abstract = {[This corrects the article DOI: 10.1038/s41522-017-0027-0.].},
}
@article {pmid30109045,
year = {2018},
author = {Hannig, C and Helbig, R and Hilsenbeck, J and Werner, C and Hannig, M},
title = {Impact of the springtail's cuticle nanotopography on bioadhesion and biofilm formation in vitro and in the oral cavity.},
journal = {Royal Society open science},
volume = {5},
number = {7},
pages = {171742},
doi = {10.1098/rsos.171742},
pmid = {30109045},
issn = {2054-5703},
abstract = {Springtails (Collembola) have a nanostructured cuticle. To evaluate and to understand anti-biofouling properties of springtail cuticles' morphology under different conditions, springtails, shed cuticles and cuticle replicates were studied after incubation with protein solutions and bacterial cultures using common in vitro models. In a second step, they were exposed to human oral environment in situ in order to explore potential application in dentistry. In vitro, the cuticular structures were found to resist wetting by albumin solutions for up to 3 h and colonization by Staphylococcus epidermidis was inhibited. When exposed in the oral cavity, initial pellicle formation was of high heterogeneity: parts of the surface were coated by adsorbed proteins, others remained uncoated but exhibited locally attached, 'bridging', proteinaceous membranes spanning across cavities of the cuticle surface; this unique phenomenon was observed for the first time. Also the degree of bacterial colonization varied considerably. In conclusion, the springtail cuticle partially modulates bioadhesion in the oral cavity in a unique and specific manner, but it has no universal effect. Especially after longer exposure, the nanotextured surface of springtails is masked by the pellicle, resulting in subsequent bacterial colonization, and, thus, cannot effectively avoid bioadhesion in the oral cavity comprehensively. Nevertheless, the observed phenomena offer valuable information and new perspectives for the development of antifouling surfaces applicable in the oral cavity.},
}
@article {pmid30108735,
year = {2017},
author = {Manukumar, HM and Chandrasekhar, B and Rakesh, KP and Ananda, AP and Nandhini, M and Lalitha, P and Sumathi, S and Qin, HL and Umesha, S},
title = {Novel T-C@AgNPs mediated biocidal mechanism against biofilm associated methicillin-resistant Staphylococcus aureus (Bap-MRSA) 090, cytotoxicity and its molecular docking studies.},
journal = {MedChemComm},
volume = {8},
number = {12},
pages = {2181-2194},
doi = {10.1039/c7md00486a},
pmid = {30108735},
issn = {2040-2503},
abstract = {Staphylococcus aureus is a commonly found pathogen that can cause food-spoilage and life threatening infections. However, the potential molecular effects of natural active thymol molecules and chitosan silver nanoparticles (C@AgNPs) in bacteria remain unclear. This gap in the literature has prompted us to study the effects of thymol loaded chitosan silver nanoparticles (T-C@AgNPs) against biofilm associated proteins in methicillin-resistant S. aureus (Bap-MRSA) 090 and also their toxicity, anti-cancer activity, and validation of their in silico molecular docking. The results showed excellent antibacterial activity of T-C@AgNPs against Bap-MRSA 090, having a minimum inhibitory concentration of 100 μg mL-1 and a 10.08 ± 0.06 mm zone of inhibition (ZOI). The cyclic voltammogram (CV) analysis clearly showed pore forming of T-C@AgNPs at 300 μg mL-1 concentration, and evidence of the interruption of the electron transport chain was clearly seen. The 200 μg mL-1 concentration exhibited a 52.60 ± 0.25% anti-biofilm property by T-C@AgNPs against Bap-MRSA 090. The T-C@AgNPs showed no toxicity to peripheral blood mononuclear cells (PBMC) (IC50 = 221 ± 0.71 μg mL-1) compared to the control, and anti-cancer activity against human triple negative breast cancer cell line (MDA-MB-231) (IC50 110 ± 1.0 μg mL-1) compared to the standard drug Doxorubicin (IC50 = 19 ± 1.0). The excellent properties of T-C@AgNPs were validated by in silico molecular docking studies and showed best match scoring to target proteins compared to standards. These excellent properties of T-C@AgNPs highlight for the first time its pharmacology and potential in medicinal drug development applications for future research.},
}
@article {pmid30107778,
year = {2018},
author = {Pericolini, E and Colombari, B and Ferretti, G and Iseppi, R and Ardizzoni, A and Girardis, M and Sala, A and Peppoloni, S and Blasi, E},
title = {Real-time monitoring of Pseudomonas aeruginosa biofilm formation on endotracheal tubes in vitro.},
journal = {BMC microbiology},
volume = {18},
number = {1},
pages = {84},
doi = {10.1186/s12866-018-1224-6},
pmid = {30107778},
issn = {1471-2180},
abstract = {BACKGROUND: Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for both acute and chronic infections in humans. In particular, its ability to form biofilm, on biotic and abiotic surfaces, makes it particularly resistant to host's immune defenses and current antibiotic therapies as well. Innovative antimicrobial materials, like hydrogel, silver salts or nanoparticles have been used to cover new generation catheters with promising results. Nevertheless, biofilm remains a major health problem. For instance, biofilm produced onto endotracheal tubes (ETT) of ventilated patients plays a relevant role in the onset of ventilation-associated pneumonia. Most of our knowledge on Pseudomonas aeruginosa biofilm derives from in vitro studies carried out on abiotic surfaces, such as polystyrene microplates or plastic materials used for ETT manufacturing. However, these approaches often provide underestimated results since other parameters, in addition to bacterial features (i.e. shape and material composition of ETT) might strongly influence biofilm formation.<br><br>RESULTS: We used an already established biofilm development assay on medically-relevant foreign devices (CVC catheters) by a stably transformed bioluminescent (BLI)-Pseudomonas aeruginosa strain, in order to follow up biofilm formation on ETT by bioluminescence detection. Our results demonstrated that it is possible: i) to monitor BLI-Pseudomonas aeruginosa biofilm development on ETT pieces in real-time, ii) to evaluate the three-dimensional structure of biofilm directly on ETT, iii) to assess metabolic behavior and the production of microbial virulence traits of bacteria embedded on ETT-biofilm.<br><br>CONCLUSIONS: Overall, we were able to standardize a rapid and easy-to-perform in vitro model for real-time monitoring Pseudomonas aeruginosa biofilm formation directly onto ETT pieces, taking into account not only microbial factors, but also ETT shape and material. Our study provides a rapid method for future screening and validation of novel antimicrobial drugs as well as for the evaluation of novel biomaterials employed in the production of new classes of ETT.},
}
@article {pmid30107456,
year = {2018},
author = {Coenye, T and Kjellerup, B},
title = {Editorial: Cross-disciplinary biofilm research-an introduction to the fourth thematic issue on biofilms.},
journal = {Pathogens and disease},
volume = {76},
number = {6},
pages = {},
doi = {10.1093/femspd/fty061},
pmid = {30107456},
issn = {2049-632X},
}
@article {pmid30107112,
year = {2018},
author = {Seo, Y and Leong, J and Park, JD and Hong, YT and Chu, SH and Park, C and Kim, DH and Deng, YH and Dushnov, V and Soh, J and Rogers, S and Yang, YY and Kong, H},
title = {Diatom Microbubbler for Active Biofilm Removal in Confined Spaces.},
journal = {ACS applied materials &amp; interfaces},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsami.8b08643},
pmid = {30107112},
issn = {1944-8252},
abstract = {Bacterial biofilms form on and within many living tissues, medical devices, and engineered materials, threatening human health and sustainability. Removing biofilm remains a grand challenge despite tremendous efforts made so far, particularly when they are formed in confined spaces. One primary cause is the limited transport of anti-bacterial agents into extracellular polymeric substances (EPS) of the biofilm. In this study, we hypothesized that a microparticle engineered to be self-motile with microbubbles would clean a structure fouled by biofilm by fracturing the EPS and subsequently improving transports of the antiseptic reagent. We examined this hypothesis by doping a hollow cylinder-shaped diatom biosilica with manganese oxide (MnO2) nanosheets. In an antiseptic H2O2 solution, the diatoms doped by MnO2 nanosheets, denoted as diatom bubbler, discharged oxygen gas bubbles continuously and became self-motile. Subsequently, the diatoms infiltrated the bacterial biofilm formed on either flat or micro-grooved silicon substrates and continued to generate microbubbles. The resulting microbubbles merged and converted surface energy to mechanical energy high enough to fracture the matrix of biofilm. Consequently, H2O2 molecules diffused into the biofilm and killed most bacterial cells. Overall, this study provides a unique and powerful tool that can significantly impact current efforts to clean a wide array of bio-fouled products and devices.},
}
@article {pmid30106284,
year = {2018},
author = {Lai, CY and Dong, QY and Chen, J and Zhu, QS and Yang, X and Chen, WD and Zhao, HP and Zhu, L},
title = {Role of Extracellular Polymeric Substances in a Methane Based Membrane Biofilm Reactor Reducing Vanadate.},
journal = {Environmental science &amp; technology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.est.8b02374},
pmid = {30106284},
issn = {1520-5851},
abstract = {For the first time, we demonstrated vanadate (V(V)) reduction in a membrane biofilm reactor (MBfR) using CH4 as the sole electron donor. V(V)-reducing capability of the biofilm kept increasing, with complete removal of V(V) achieved when the influent surface loading of V(V) was 363 mg m-2 day-1. Almost all V(V) was reduced to V(IV) precipitates, which is confirmed by scanning electron microscope coupled to energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray photoelectron spectroscope (XPS). Microbial community analysis revealed that denitrifiers Methylomonas and Denitratisoma might be the main genera responsible for V(V) reduction. The constant enrichment of Methylophilus suggests that the intermediate (i.e., methanol) from CH4 metabolism was used as the electron carriers for V(V) bioreduction. Intrusion of V(V) (2-5 mg/L, at the surface loading of 150-378 mg m-2 day-1) into the biofilm stimulated the secretion of extracellular polymeric substances (EPS), but high loading of V(V) (10 mg/L, at the surface loading of 668 mg m-2 day-1) decreased the amount of EPS. Metagenomic prediction analysis established the strong correlation between the secretion of EPS and the microbial metabolism associated with V(V) reduction, tricarboxylic acid cycle (TCA) cycle, methane oxidation and ATP production, and EPS might relieve the oxidative stress induced by high loading of V(V). Colorimetric determination and three-dimensional excitation-emission matrix (3D-EEM) showed that tryptophan and humic acid-like substances might play important roles in microbial cells protection and V(V) binding. Fourier transform infrared (FTIR) spectroscopy identified hydroxyl (-OH), and carboxyl (COO-) groups in EPS as the candidate functional groups for binding V(V).},
}
@article {pmid30105835,
year = {2018},
author = {Hartmann, RC and Neuvald, L and Barth, V and de Figueiredo, JAP and de Oliveira, SD and Scarparo, RK and Waltrick, SB and Rossi-Fedele, G},
title = {Antimicrobial efficacy of 0.5% peracetic acid and EDTA with passive ultrasonic or manual agitation in an Enterococcus faecalis biofilm model.},
journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc},
volume = {},
number = {},
pages = {},
doi = {10.1111/aej.12279},
pmid = {30105835},
issn = {1747-4477},
abstract = {We compared the antimicrobial efficacy of EDTA and 0.5% peracetic acid (PAA), with manual agitation (MA) or passive ultrasonic irrigation (PUI) in an Enterococcus faecalis biofilm model. Fifty-five single-rooted human premolar teeth were chemo-mechanically prepared and inoculated with E. faecalis for biofilm formation. These were divided into five groups (n = 11): saline solution, PAA+MA, PAA+PUI, EDTA+MA and EDTA+PUI. Root canal sampling and scanning electron microscopy of the canal lumen and dentinal tubule areas at the different root thirds were performed. The images were ranked based on contamination level. Only the PAA groups presented with no bacterial growth, with the remaining groups not presenting significant differences among them. PAA+PUI presented with the highest median position rankings in every third and location, whereas EDTA+MA performed similarly to the saline control. No differences were found when comparing MA and PUI within the same solution, however, PUI was associated with lower contamination levels mean rankings.},
}
@article {pmid30105081,
year = {2018},
author = {Viola, CM and Torres-Carro, R and Cartagena, E and Isla, MI and Alberto, MR and Arena, ME},
title = {Effect of Wine Wastes Extracts on the Viability and Biofilm Formation of Pseudomonas aeruginosa and Staphylococcus aureus Strains.},
journal = {Evidence-based complementary and alternative medicine : eCAM},
volume = {2018},
number = {},
pages = {9526878},
doi = {10.1155/2018/9526878},
pmid = {30105081},
issn = {1741-427X},
abstract = {In this work, we intended to inhibit the biofilm synthesis and the metabolism of Gram-positive and Gram-negative bacteria using two highly available wastes (stem and marc) obtained after the manufacturing of Torrontes wine at Cafayate, Argentina. Wine wastes contain a significant amount of bioactive compounds, mainly phenolic compounds, which makes them a potential source of compounds with beneficial properties to human health, as they could inhibit the virulence of pathogenic bacteria or protect the tissue against oxidative stress. Marc and stem extracts of Torrontes wine were evaluated for their ability to inhibit the metabolism and biofilm production of Pseudomonas aeruginosa and Staphylococcus aureus strains. The phytochemical composition and antioxidant activity of these extracts were also determined. The methanol and ethyl acetate extracts, which contained the highest amount of total polyphenolic, exhibited the highest scavenging capacity of ABTS and nitric oxide and the strongest Fe3+ reducing power and exhibited the highest level of inhibition of the biofilm formation and of the metabolic activity in bacterial biofilm. We also noticed a positive correlation between phenolic compounds content, the antioxidant activity, and the anti-biofilm capacity of the winemaking wastes. These results display the potentiality of wine wastes to prevent or reduce the formation of biofilm. Moreover, their abundance makes them an attractive and affordable source of antibiofilm and antioxidant agents.},
}
@article {pmid30104272,
year = {2018},
author = {Guillon, A and Fouquenet, D and Morello, E and Henry, C and Georgeault, S and Si-Tahar, M and Hervé, V},
title = {Treatment of Pseudomonas aeruginosa biofilm present in endotracheal tubes by poly-L-Lysine.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.00564-18},
pmid = {30104272},
issn = {1098-6596},
abstract = {The endotracheal tube (ETT) is an essential interface between the patient and ventilator in mechanically-ventilated patients. However, a microbial biofilm is formed gradually on this tube and is associated with the development of ventilator-associated pneumonia. Bacteria present in the biofilm are more resistant to antibiotics and current medical practices do not make it possible to eliminate. P. aeruginosa is one of the leading pathogens that cause biofilm infections and ventilator-associated pneumonia. Poly-L-lysine (pLK) is a cationic polypeptide possessing antibacterial properties and mucolytic activity by compacting DNA. We explored here the anti-biofilm activity of pLK to treat P. aeruginosa biofilms on ETT, taking into consideration the necessary constraints for clinical translation in our experimental designs. First, we showed that pLK eradicate P. aeruginosa biofilm formed in vitro on 96-well microplates. We further demonstrated that pLK alters bacterial membrane integrity as revealed by scanning electron microscopy and eventually eradicate biofilm formed either by reference or clinical strains of P. aeruginosa biofilms generated in vitro on ETT. Second, we collected ETT from patients with P. aeruginosa ventilator-associated pneumonia. We observed that a single dose of pLK is able to immediately disrupt the biofilm structure and kills more than 90 % of bacteria present in biofilm. Additionally, we did not observe any lung tolerance issue when pLK solution was instilled into ETT of ventilated-pigs, an animal model particularly relevant to mimic invasive mechanical ventilation in humans. In conclusion, pLK appears as an innovative anti-biofilm molecule which could be applied in the ETT of mechanically-ventilated patients.},
}
@article {pmid30101982,
year = {2018},
author = {Puah, SM and Tan, JAMA and Chew, CH and Chua, KH},
title = {Diverse Profiles of Biofilm and Adhesion Genes in Staphylococcus Aureus Food Strains Isolated from Sushi and Sashimi.},
journal = {Journal of food science},
volume = {},
number = {},
pages = {},
doi = {10.1111/1750-3841.14300},
pmid = {30101982},
issn = {1750-3841},
abstract = {Staphylococcus aureus is able to form multilayer biofilms embedded within a glycocalyx or slime layer. Biofilm formation poses food contamination risks and can subsequently increase the risk of food poisoning. Identification of food-related S. aureus strains will provide additional data on staphylococcal food poisoning involved in biofilm formation. A total of 52 S. aureus strains isolated from sushi and sashimi was investigated to study their ability for biofilm formation using crystal violet staining. The presence of accessory gene regulator (agr) groups and 15 adhesion genes was screened and their associations in biofilm formation were studied. All 52 S. aureus strains showed biofilm production on the tested hydrophobic surface with 44% (23/52) strains classified as strong, 33% (17/52) as moderate, and 23% (12/52) as weak biofilm producers. The frequency of agr-positive strains was 71% (agr group 1 = 21 strains; agr group 2 = 2 strains; agr group 3 = 12 strains; agr group 4 = 2 strains) whereas agr-negative strains were 29% (15/52). Twelve adhesion genes were detected and 98% of the S. aureus strains carried at least one adhesion gene. The ebps was significantly (p < .05) associated with strong biofilm producing strains. In addition, eno, clfA, icaAD, sasG, fnbB, cna, and sasC were significantly higher in the agr-positive group compared to the agr-negative group. The results of this study suggest that the presence of ebps, eno, clfA, icaAD, sasG, fnbB, cna, and sasC may play an important role in enhancing the stage of biofilm-related infections and warrants further investigation.<br><br>PRACTICAL APPLICATION: This work contributes to the knowledge on the biofilm formation and the distribution of agr groups in S. aureus strains as well as microbial surface components in recognizing adherence matrix molecules of organisms isolated from ready-to-eat sushi and sashimi. The findings provide valuable information to further study the roles of specific genes in causing biofilm-related infections.},
}
@article {pmid30100555,
year = {2018},
author = {Adler, E and Miller, D and Rock, O and Spierer, O and Forster, R},
title = {Microbiology and biofilm of corneal sutures.},
journal = {The British journal of ophthalmology},
volume = {},
number = {},
pages = {},
doi = {10.1136/bjophthalmol-2018-312133},
pmid = {30100555},
issn = {1468-2079},
abstract = {AIM: To investigate the relationships between corneal suture bacteriology, biofilm and the clinical setting using culture studies and scanning electron microscopy (SEM).<br><br>METHODS: This is a prospective, observational study of patients with a history of penetrating keratoplasty presenting to a tertiary cornea clinic for routine or symptoms-related corneal suture removal. We documented for each patient the suture clinical setting (quiescent, exposed and keratitis-related), retention time, antimicrobial therapy, bacterial growth on culture studies, and bacterial presence and biofilm coverage on SEM.<br><br>RESULTS: There were significantly different culture positivity rates between the quiescent (8%), exposed (12%) and keratitis-related (60%) suture groups (p=0.039). As expected, keratitis-related sutures had the longest retention time compared with quiescent and exposed ones (p=0.02). The biofilm coverage score was higher for sutures from the keratitis-related and exposed groups, although this trend was not statistically significant (p=0.90). Higher biofilm scores were seen in samples that also yielded a positive culture result (p=0.36) and in samples with bacterial presence on SEM images (p=0.16 and p=0.73). Both of these were important trends but not statistically significant.<br><br>CONCLUSIONS: Evidence for active bacterial and biofilm presence on corneal sutures was found. Corneal sutures should be considered for removal sooner, before becoming exposed and/or keratitis-related. Traditional culture studies and SEM imaging are helpful in investigating biofilm and its clinical importance. More studies of the spectrum of bacterial growth on embedded biomedical devices such as corneal sutures are needed.},
}
@article {pmid30098341,
year = {2018},
author = {Erskine, EE and MacPhee, CE and Stanley-Wall, NR},
title = {Functional Amyloid and Other Protein Fibres in the Biofilm Matrix.},
journal = {Journal of molecular biology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jmb.2018.07.026},
pmid = {30098341},
issn = {1089-8638},
abstract = {Biofilms are ubiquitous in the natural and man-made environment. They are defined as microbes that are encapsulated in an extracellular, self-produced, biofilm matrix. Growing evidence from the genetic and biochemical analysis of single species biofilms has linked the presence of fibrous proteins to a functional biofilm matrix. Some of these fibres have been described as functional amyloid or amyloid-like fibres. Here we provide an overview of the biophysical and biological data for a wide range of protein fibres found in the biofilm matrix of Gram-positive and Gram-negative bacteria.},
}
@article {pmid30097756,
year = {2018},
author = {da Silveira, PV and Panariello, BHD and de Araújo Costa, CAG and Maule, SM and Maule, SM and Janal, MN and Zanin, ICJ and Duarte, S},
title = {Twice-daily red and blue light treatment for Candida albicans biofilm matrix development control.},
journal = {Lasers in medical science},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10103-018-2610-x},
pmid = {30097756},
issn = {1435-604X},
support = {CAPES 88881.062159̷ 2014-01 PVE̷ CAPES//Coordination for the Improvement of Higher Level Personnel (CAPES)/ ; },
abstract = {Phototherapy has been proposed as a direct means of affecting local bacterial infections. However, the use of phototherapy to prevent fungal biofilm development has received comparatively less attention. This study aimed to determine the effects of red light treatment and blue light treatment, without a photosensitizer, on the development of Candida albicans biofilm. During the development of 48-h biofilms of C. albicans SN 425 (n = 10), the biofilms were exposed twice-daily to noncoherent blue and red light (LumaCare; 420 nm and 635 nm). The energy density applied was 72 J cm-2 for blue light and 43.8 J cm2, 87.6 J cm2, and 175.5 J cm2 for red light. Positive control (PC) and negative control (NC) groups were treated twice-daily for 1 min with 0.12% chlorhexidine (CHX) and 0.89% NaCl respectively. Biofilms were analyzed for colony forming units (CFU), dry-weight, and exopolysaccharides (EPS-soluble and EPS-insoluble). Data was analyzed by one-way ANOVA and Tukey post hoc test (α = 0.05). Dry-weight was lower than NC (p < 0.001) and approached PC levels with both red and blue light treatments. CFU were also lower in groups exposed to blue light and higher durations of red light (p < 0.05). EPS-soluble and EPS-insoluble measures were variably reduced by these light exposures. In conclusion, twice-daily exposure to both blue and red lights affect the biofilm development and physiology of polysaccharide production and are potential mechanisms for the control of C. albicans biofilm matrix development.},
}
@article {pmid30097647,
year = {2018},
author = {van Wolferen, M and Orell, A and Albers, SV},
title = {Archaeal biofilm formation.},
journal = {Nature reviews. Microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41579-018-0058-4},
pmid = {30097647},
issn = {1740-1534},
abstract = {Biofilms are structured and organized communities of microorganisms that represent one of the most successful forms of life on Earth. Bacterial biofilms have been studied in great detail, and many molecular details are known about the processes that govern bacterial biofilm formation, however, archaea are ubiquitous in almost all habitats on Earth and can also form biofilms. In recent years, insights have been gained into the development of archaeal biofilms, how archaea communicate to form biofilms and how the switch from a free-living lifestyle to a sessile lifestyle is regulated. In this Review, we explore the different stages of archaeal biofilm development and highlight similarities and differences between archaea and bacteria on a molecular level. We also consider the role of archaeal biofilms in industry and their use in different industrial processes.},
}
@article {pmid30096872,
year = {2018},
author = {Caputo, P and Di Martino, MC and Perfetto, B and Iovino, F and Donnarumma, G},
title = {Use of MALDI-TOF MS to Discriminate between Biofilm-Producer and Non-Producer Strains of Staphylococcus epidermidis.},
journal = {International journal of environmental research and public health},
volume = {15},
number = {8},
pages = {},
doi = {10.3390/ijerph15081695},
pmid = {30096872},
issn = {1660-4601},
abstract = {For the management of Staphylococci coagulase-negative infection, often related to biofilm formation, rapid and accurate identification is necessary in choosing a correct antibiotic therapy. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is becoming increasingly important for bacterial identification over traditional methods. Our aim was to validate the use of MALDI to discriminate Staphylococcus epidermidis biofilm-producing strains. Clinical strains coming from suture wires were identified and their protein profiles were compared to that obtained from two ATCC reference strains (biofilm producer and non-producer). MALDI identified the eighteen isolates as S. epidermidis, combining sixteen profiles with the biofilm producer and two with the non-producer, confirming the results of crystal violet assay. Our data highlight that MALDI can be considered a good tool to discriminate between biofilm-producer and non-producer strains of S. epidermidis, thus helping to establish an effective antibiotic therapy.},
}
@article {pmid30096668,
year = {2018},
author = {Morón-López, J and Nieto-Reyes, L and Senán-Salinas, J and Molina, S and El-Shehawy, R},
title = {Recycled desalination membranes as a support material for biofilm development: A new approach for microcystin removal during water treatment.},
journal = {The Science of the total environment},
volume = {647},
number = {},
pages = {785-793},
doi = {10.1016/j.scitotenv.2018.07.435},
pmid = {30096668},
issn = {1879-1026},
abstract = {Increased harmful cyanobacterial blooms and drought are some negative impacts of global warming. To deal with cyanotoxin release during water treatment, and to manage the massive quantities of end-of-life membrane waste generated by desalination processes, we propose an innovative biological system developed from recycled reverse osmosis (RO) membranes to remove microcystins (MC). Our system, named the Recycled-Membrane Biofilm Reactor (R-MBfR), effectively removes microcystins, while reducing the pollution impact of RO membrane waste by prolonging their life span at the same time. This multidisciplinary work showed that the inherent flaw of RO membranes, i.e., fouling, can be considered an advantageous characteristic for biofilm attachment. Factors such as roughness, hydrophilic surfaces, and the role of calcium in cell-cell and cell-surface interactions, encouraged bacterial growth on discarded membranes. Biofilm development was stimulated by using a laboratory-scale membrane module simulator cell. The R-MBfR proved versatile and was capable of degrading 2 mg·L-1 of MC in 24 h. The economic feasibility of the scaling-up of the hypothetical R-MBfR was also validated. Therefore, this membrane recycling could be a future green cost-effective alternative technology for MC removal.},
}
@article {pmid30096560,
year = {2018},
author = {Ostadhossein, F and Misra, SK and Tripathi, I and Kravchuk, V and Vulugundam, G and LoBato, D and Selmic, LE and Pan, D},
title = {Dual purpose hafnium oxide nanoparticles offer imaging Streptococcus mutans dental biofilm and fight it In vivo via a drug free approach.},
journal = {Biomaterials},
volume = {181},
number = {},
pages = {252-267},
doi = {10.1016/j.biomaterials.2018.07.053},
pmid = {30096560},
issn = {1878-5905},
abstract = {The removal of tenacious dental plaque is of paramount importance; however, early diagnosis can be a challenging task in dental clinics due to the limitations of current approaches, specifically X-ray-based techniques. We have approached this problem by integrating antibacterial properties and X-ray contrast enhancement in a single probe specific to colonies of Streptococcus mutans as the most predominant and carious oral bacteria. We report the synthesis of an inherently therapeutic polymeric silane conjugated hafnium oxide nanoparticles (Hf PS NPs). Using a high-affinity pathogen-selective peptide, the concept of molecularly targeted X-ray imaging of cariogenic pathogen S. mutans was demonstrated. Ex vivo studies using extracted human tooth demonstrated striking X-ray attenuation of NPs vs. tooth. Additionally, Hf PS NPs exhibited significant bactericidal properties against cariogenic pathogen. Electron microscopy revealed that the antibacterial activity occurred via a 'latch and kill' mechanism. Mechanistic studies determined that these NPs fragmented bacterial DNA components to exert their antimicrobial effect. Importantly, Hf PS NPs effectively inhibited the growth of a mature biofilm on an ex vivo human tooth model. Finally, the NPs were applied to the rodent model of dental biofilm. Topical administration of the Hf PS NPs for 8 days (1X daily) could effectively attenuate the S. mutans biofilm challenge. This report is the first of its kind to demonstrate that HfO2-based NPs can be used for simultaneous diagnosis and antibacterial treatment without requiring an additional drug.},
}
@article {pmid30093898,
year = {2018},
author = {Selvarajoo, K},
title = {Order Parameter in Bacterial Biofilm Adaptive Response.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1721},
doi = {10.3389/fmicb.2018.01721},
pmid = {30093898},
issn = {1664-302X},
}
@article {pmid30093624,
year = {2018},
author = {Fernández-Barat, L and Ben-Aicha, S and Motos, A and Vila, J and Marco, F and Rigol, M and Muñoz, L and Li Bassi, G and Ferrer, M and Torres, A},
title = {Assessment of in vivo versus in vitro biofilm formation of clinical methicillin-resistant Staphylococcus aureus isolates from endotracheal tubes.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {11906},
doi = {10.1038/s41598-018-30494-7},
pmid = {30093624},
issn = {2045-2322},
abstract = {Our aim was to demonstrate that biofilm formation in a clinical strain of methicillin-resistant Staphylococcus aureus (MRSA) can be enhanced by environment exposure in an endotracheal tube (ETT) and to determine how it is affected by systemic treatment and atmospheric conditions. Second, we aimed to assess biofilm production dynamics after extubation. We prospectively analyzed 70 ETT samples obtained from pigs randomized to be untreated (controls, n = 20), or treated with vancomycin (n = 32) or linezolid (n = 18). A clinical MRSA strain (MRSA-in) was inoculated in pigs to create a pneumonia model, before treating with antibiotics. Tracheally intubated pigs with MRSA severe pneumonia, were mechanically ventilated for 69 ± 16 hours. All MRSA isolates retrieved from ETTs (ETT-MRSA) were tested for their in vitro biofilm production by microtiter plate assay. In vitro biofilm production of MRSA isolates was sequentially studied over the next 8 days post-extubation to assess biofilm capability dynamics over time. All experiments were performed under ambient air (O2) or ambient air supplemented with 5% CO2. We collected 52 ETT-MRSA isolates (placebo N = 19, linezolid N = 11, and vancomycin N = 22) that were clonally identical to the MRSA-in. Among the ETT-MRSA isolates, biofilm production more than doubled after extubation in 40% and 50% under 5% CO2 and O2, respectively. Systemic antibiotic treatment during intubation did not affect this outcome. Under both atmospheric conditions, biofilm production for MRSA-in was at least doubled for 9 ETT-MRSA isolates, and assessment of these showed that biofilm production decreased progressively over a 4-day period after extubation. In conclusion, a weak biofilm producer MRSA strain significantly enhances its biofilm production within an ETT, but it is influenced by the ETT environment rather than by the systemic treatment used during intubation or by the atmospheric conditions used for bacterial growth.},
}
@article {pmid30092027,
year = {2018},
author = {Bosse, M and Heuwieser, A and Heinzel, A and Lukas, A and Oliveira, G and Mayer, B},
title = {Biomarker panels for characterizing microbial community biofilm formation as composite molecular process.},
journal = {PloS one},
volume = {13},
number = {8},
pages = {e0202032},
doi = {10.1371/journal.pone.0202032},
pmid = {30092027},
issn = {1932-6203},
abstract = {Microbial consortia execute collaborative molecular processes with contributions from individual species, on such basis enabling optimized molecular function. Such collaboration and synergies benefit metabolic flux specifically in extreme environmental conditions as seen in acid mine drainage, with biofilms as relevant microenvironment. However, knowledge about community species composition is not sufficient for deducing presence and efficiency of composite molecular function. For this task molecular resolution of the consortium interactome is to be retrieved, with molecular biomarkers particularly suited for characterizing composite molecular processes involved in biofilm formation and maintenance. A microbial species set identified in 18 copper environmental sites provides a data matrix for deriving a cross-species molecular process model of biofilm formation composed of 191 protein coding genes contributed from 25 microbial species. Computing degree and stress centrality of biofilm molecular process nodes allows selection of network hubs and central connectors, with the top ranking molecular features proposed as biomarker candidates for characterizing biofilm homeostasis. Functional classes represented in the biomarker panel include quorum sensing, chemotaxis, motility and extracellular polysaccharide biosynthesis, complemented by chaperones. Abundance of biomarker candidates identified in experimental data sets monitoring different biofilm conditions provides evidence for the selected biomarkers as sensitive and specific molecular process proxies for capturing biofilm microenvironments. Topological criteria of process networks covering an aggregate function of interest support the selection of biomarker candidates independent of specific community species composition. Such panels promise efficient screening of environmental samples for presence of microbial community composite molecular function.},
}
@article {pmid30090964,
year = {2018},
author = {Jamal, M and Andleeb, S and Jalil, F and Imran, M and Nawaz, MA and Hussain, T and Ali, M and Ur Rahman, S and Das, CR},
title = {Isolation, characterization and efficacy of phage MJ2 against biofilm forming multi-drug resistant Enterobacter cloacae.},
journal = {Folia microbiologica},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12223-018-0636-x},
pmid = {30090964},
issn = {1874-9356},
support = {HEC-IRSIP- 2013//Higher Education Commision, Pakistan/ ; },
abstract = {Biofilm is involved in a variety of infections, playing a critical role in the chronicity of infections. Enterobacter cloacae is a biofilm-forming and multi-drug-resistant (MDR) nosocomial pathogen leading to significant morbidity and mortality. This study aimed at isolation of a bacteriophage against MDR clinical strain of E. cloacae and its efficacy against bacterial planktonic cells and biofilm. A bacteriophage MJ2 was successfully isolated from wastewater and was characterized. The phage exhibited a wide range of thermal and pH stability and demonstrated considerable adsorption to host bacteria in the presence of CaCl2 or MgCl2. Transmission electron microscopy (TEM) showed MJ2 head as approximately 62 and 54 nm width and length, respectively. It had a short non-contractile tail and was characterized as a member of the family Podoviridae [order Caudovirales]. The phage MJ2 was found to possess 11 structural proteins (12-150 kDa) and a double-stranded DNA genome with an approximate size of 40 kb. The log-phase growth of E. cloacae both in biofilm and suspension was significantly reduced by the phage. The E. cloacae biofilm was formed under different conditions to evaluate the efficacy of MJ2 phage. Variable reduction pattern of E. cloacae biofilm was observed while treating it for 4 h with MJ2, i.e., biofilm under static conditions. The renewed media with intervals of 24, 72, and 120 h showed biomass decline of 2.8-, 3-, and 3.5-log, respectively. Whereas, the bacterial biofilm formed with dynamic conditions with refreshing media after 24, 72, and 120 h demonstrated decline in growth at 2.5-, 2.6-, and 3.3-log, respectively. It was, therefore, concluded that phage MJ2 possessed considerable inhibitory effects on MDR E. cloacae both in planktonic and biofilm forms.},
}
@article {pmid30090117,
year = {2018},
author = {Pourhajibagher, M and Chiniforush, N and Monzavi, A and Barikani, H and Monzavi, MM and Sobhani, S and Shahabi, S and Bahador, A},
title = {Inhibitory Effects of Antimicrobial Photodynamic Therapy with Curcumin on Biofilm-Associated Gene Expression Profile of Aggregatibacter actinomycetemcomitans.},
journal = {Journal of dentistry (Tehran, Iran)},
volume = {15},
number = {3},
pages = {169-177},
pmid = {30090117},
issn = {1735-2150},
abstract = {Objectives: Periodontitis is an inflammation of periodontal tissues that is caused by the biofilm of periodontal pathogens. Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) is an opportunistic periodontopathogen that can be the cause of periodontal diseases via fimbriae as a virulence factor. In this study, we aimed to determine the expression level of A. actinomycetemcomitans rcpA gene as a virulence factor associated with biofilm formation after antimicrobial photodynamic therapy (aPDT) as a relatively new therapeutic modality.<br><br>Materials and Methods: To determine sub-lethal doses of aPDT against A. actinomycetemcomitans ATCC 33384 strain, we used curcumin (CUR) as a photosensitizer at a final concentration of 40 μmol/ml, which was excited with a light-emitting diode (LED) at the wavelength of 450 nm. Quantitative real-time polymerase chain reaction (qRT-PCR) was then applied to monitor rcpA gene expression in A. actinomycetemcomitans.<br><br>Results: 10-40 μmol/ml of CUR caused a significant reduction in the growth of A. actinomycetemcomitans compared to control group (P<0.05). Also, the cell viability of A. actinomycetemcomitans was significantly decreased after more than four minutes of LED irradiation. Therefore, the sub-lethal dose of aPDT against A. actinomycetemcomitans was 5 μmol/ml of CUR with three minutes of LED irradiation at a fluency of 180-240 J/cm2, which reduced the expression of the rcpA gene by approximately 8.5-fold.<br><br>Conclusions: aPDT with CUR leads to decreased cell survival and virulence of A. actinomycetemcomitans. Thus, CUR-aPDT can be used as an alternative approach for the successful treatment of periodontitis in vivo.},
}
@article {pmid30090115,
year = {2018},
author = {Ghabraei, S and Bolhari, B and Sabbagh, MM and Afshar, MS},
title = {Comparison of Antimicrobial Effects of Triple Antibiotic Paste and Calcium Hydroxide Mixed with 2% Chlorhexidine as Intracanal Medicaments Against Enterococcus faecalis Biofilm.},
journal = {Journal of dentistry (Tehran, Iran)},
volume = {15},
number = {3},
pages = {151-160},
pmid = {30090115},
issn = {1735-2150},
abstract = {Objectives: The purpose of this in-vitro study was to determine and compare the shortest period needed for a triple antibiotic paste (TAP) and calcium hydroxide (Ca(OH)2) plus 2% chlorhexidine (CHX) to eradicate the biofilm of Enterococcus faecalis (EF) from the root canal system.<br><br>Materials and Methods: Sixty-five extracted single-rooted human teeth with straight root canals were selected. The crowns were cut from the cementoenamel junction (CEJ), and canal preparations were done by step-back technique. The smear layer was removed by 17% ethylenediaminetetraacetic acid (EDTA) and 5.25% sodium hypochlorite (NaOCl). Afterwards, the samples were sterilized with gamma ray and were placed inside microtubes for one week. During this week, the teeth were infected with EF. Then, a TAP and Ca(OH)2 mixed with 2% CHX were inserted into the canals. The roots were cut longitudinally, and dentin chips were collected from the apical part of the roots by a round bur to the depth of 400 μm. The vital bacterial load was assessed by counting the numbers of colony-forming units (CFUs).<br><br>Results: The paste of Ca(OH)2 mixed with 2% CHX was able to eradicate the EF biofilm in three days. The TAP was able to eradicate the biofilm of EF in seven days.<br><br>Conclusions: It seems that Ca(OH)2 mixed with 2% CHX is more potent than the TAP against EF biofilm.},
}
@article {pmid30086343,
year = {2018},
author = {Mizdal, CR and Stefanello, ST and da Costa Flores, V and Agertt, VA and Bonez, PC and Rossi, GG and da Silva, TC and Antunes Soares, FA and de Lourenço Marques, L and de Campos, MMA},
title = {The antibacterial and anti-biofilm activity of gold-complexed sulfonamides against methicillin-resistant Staphylococcus aureus.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2018.08.002},
pmid = {30086343},
issn = {1096-1208},
abstract = {The drug-resistant strains of Staphylococcus aureus have been considered as one of the serious health threats, which are related to high patient hospitalization rates. Besides, Staphylococcus aureus biofilm formation exhibits a drug-tolerant nature and shows nonspecific resistance against a broad-spectrum of antibiotics. The emergence of drug-resistant bacteria stimulated the development of novel medicines as a strategy to control infections. In this study, we evaluated the antibacterial and anti-biofilm activity of gold-complexed sulfonamides against Staphylococcus aureus strains such as methicillin-resistant S. aureus and clinical isolates. Our data showed that the exposure of gold-complexed sulfonamides promoted a remarkable reduction in the bacterial adhesion. Also, confocal microscopy displayed the effects of the compounds on in the bacterial cell biofilm, revealed that the compounds decreased the biofilm formation. Our results also demonstrated that gold-complexed sulfonamides exhibited potent antibacterial activity against Staphylococcus aureus strains. Besides, all compounds presented a synergic antibacterial activity when were associated with classical antibiotics. Gold-complexed sulfonamide compounds did not promote toxic effects on Caenorhabditis elegans. Thus, our results showed that the coordination of sulfonamide with gold is a promising alternative in the development of safe and active compounds against methicillin-resistant and clinical isolates S. aureus.},
}
@article {pmid30084644,
year = {2018},
author = {Wang, Z and Gong, X and Xie, J and Xu, Z and Liu, G and Zhang, G},
title = {Investigation of Formation of Bacterial Biofilm upon Dead Siblings.},
journal = {Langmuir : the ACS journal of surfaces and colloids},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.langmuir.8b01962},
pmid = {30084644},
issn = {1520-5827},
abstract = {Biocides can effectively kill bacteria. However, whether the dead bacterial cells left on the surface influence the later growth of biofilm is unknown. In this study, we have cultured Pseudomonas aeruginosa (PAO1) biofilm on their dead siblings and have investigated their evolution by using magnetic force modulation atomic force microscopy (MF-AFM). The time dependence of the biofilm thickness indicates that the deposited dead siblings can slow down the growth of PAO1 biofilm. The biofilm growing on dead bacteria layers is softer in comparison with those upon alive siblings, as reflected by the static elastic modulus (E) and dynamic stiffness (kd) scaled to the disturbing frequency (f) as , where kd,0 is the scaling factor and γ is the power-law exponent. We reveal that the smaller population instead of the variation of extracellular polymeric substances (EPS) within the biofilm upon the dead siblings is responsible for the softer biofilm. The present study provides a better understanding of the biofilm formation, thus making significance for designing antimicrobial medical materials and antifouling coatings.},
}
@article {pmid30084122,
year = {2018},
author = {Kern, ZT and Jacob, ME and Gilbertie, JM and Vaden, SL and Lyle, SK},
title = {Characteristics of Dogs with Biofilm-Forming Escherichia Coli Urinary Tract Infections.},
journal = {Journal of veterinary internal medicine},
volume = {},
number = {},
pages = {},
doi = {10.1111/jvim.15231},
pmid = {30084122},
issn = {1939-1676},
abstract = {BACKGROUND: Bacterial urinary tract infections (UTIs) are common in companion animals. Increasing awareness of biofilm-forming bacteria raises concern regarding the appropriate diagnosis, treatment, and prognosis of UTIs associated with these organisms.<br><br>HYPOTHESIS/OBJECTIVES: To (1) describe the population of dogs with UTIs associated with biofilm-forming Escherichia coli and (2) determine whether or not clinical differences exist between dogs with biofilm-forming E. coli UTIs and dogs with nonbiofilm-forming E. coli UTIs. We hypothesized that there would be no difference in the population characteristics, but that biofilm-formation would be more prevalent in dogs with chronic, complicated, and asymptomatic UTIs.<br><br>ANIMALS: Seventy-six client-owned dogs with E. coli UTIs, divided into 2 groups based on the biofilm-forming capability of stored bacterial isolates as assessed by the crystal violet assay.<br><br>METHODS: Retrospective cross-sectional study. Medical records of the affected dogs were reviewed and their population and infection characteristics were compared.<br><br>RESULTS: Most (52.6%) E. coli isolates were capable of forming biofilms. Biofilm-forming E. coli had a lower likelihood (P < .001) of multidrug resistance than did nonbiofilm-forming E. coli. No statistically significant differences were identified between the population or infection characteristics of the 2 groups of dogs.<br><br>Escherichia coli isolated from canine urinary tracts are frequently capable of forming biofilms. Because no reliable clinical features allowed exclusion of biofilm formation, the potential for biofilm formation should be considered whenever E. coli UTI is diagnosed. The association of antibiotic resistance and biofilm potential may affect treatment of UTIs, but additional investigation is warranted.},
}
@article {pmid30083138,
year = {2018},
author = {Zhou, Y and Millhouse, E and Shaw, T and Lappin, DF and Rajendran, R and Bagg, J and Lin, H and Ramage, G},
title = {Evaluating Streptococcus mutans Strain Dependent Characteristics in a Polymicrobial Biofilm Community.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1498},
doi = {10.3389/fmicb.2018.01498},
pmid = {30083138},
issn = {1664-302X},
abstract = {Aim: The purpose of this study was to investigate strain dependent differences of the cariogenic biofilm forming Streptococcus mutans within both simple and complex communities. Methods: A mono-species containing representative S. mutans clinical isolates (caries and non-caries), and a multispecies in vitro caries biofilm model containing Lactobacillus casei, Veillonella dispar, Fusobacterium nucleatum and Actinomyces naeslundii, and either of two representative S. mutans clinical isolates (caries and non-caries), was developed as a comparison model. Compositional analysis of total and live bacteria within biofilms, and transcriptional analysis of biofilm associated virulence factors were evaluated by live/dead PCR and quantitative PCR, respectively. Scanning electron microscopy (SEM) was used to analyze the architecture of biofilm. One-way analysis of variance and t-tests were used to investigate significant differences between independent groups of data. Results: Within a mono-species biofilm, different S. mutans strains responded similarly to one another during biofilm formation in different carbohydrate sources, with sucrose showing the highest levels of biofilm biomass and galactose showing the lowest. Within the polymicrobial biofilm system, compositional analysis of the bacteria within the biofilm showed that S. mutans derived from a caries-free patient was preferentially composed of both total and viable L. casei, whereas S. mutans derived from a caries patient was dominated by both total and viable S. mutans (p < 0.001). Normalized gene expression analysis of srtA, gtfB, ftf, spaP, gbpB, and luxS, showed a general upregulation within the S. mutans dominant biofilm. Conclusion: We were able to demonstrate that individual strains derived from different patients exhibited altered biofilm characteristics, which were not obvious within a simple mono-species biofilm model. Influencing the environmental conditions changed the composition and functionality S. mutans within the polymicrobial biofilm. The biofilm model described herein provides a novel and reproducible method of assessing the impact on the biofilm microbiome upon different environmental influences.},
}
@article {pmid30082282,
year = {2018},
author = {Poudyal, B and Sauer, K},
title = {PA3177 encodes an active diguanylate cyclase that contributes to the biofilm antimicrobial tolerance but not biofilm formation by P. aeruginosa.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01049-18},
pmid = {30082282},
issn = {1098-6596},
abstract = {A hallmark of biofilms is their heightened resistance to antimicrobial agents. Recent findings suggested a role of c-di-GMP in the susceptibility of bacteria to antimicrobial agents, however, no c-di-GMP modulating enzyme(s) contributing to the drug tolerance phenotype of biofilms has been identified. The goal of this study was to determine whether c-di-GMP modulating enzyme(s) specifically contribute to the biofilm drug tolerance of Pseudomonas aeruginosa. Using RNA-Seq combined with biofilm susceptibility assays, we identified PA3177 encoding a probable diguanylate cyclase. PA3177 was confirmed to be an active diguanylate cyclase, with overexpression affecting swimming and swarming motility, and inactivation affecting cellular c-di-GMP levels of biofilm but not planktonic cells. Inactivation of PA3177 rendered P. aeruginosa PAO1 biofilms susceptible to tobramycin and hydrogen peroxide. Inactivation of PA3177 furthermore eliminated the recalcitrance of biofilms to killing by tobramycin, with multicopy expression of PA3177 but not PA3177_GGAAF harboring substitutions in the active site, restoring tolerance to wild-type levels. Susceptibility was linked to BrlR, a previously described transcriptional regulator contributing to biofilm tolerance, with inactivation of PA3177 negatively impacting BrlR levels and BrlR-DNA binding. While PA3177 contributed to biofilm drug tolerance, inactivation of PA3177 had no effect on attachment and biofilm formation. Our findings demonstrate for the first time that biofilm drug tolerance by P. aeruginosa is linked to a specific c-di-GMP modulating enzyme, PA3177, with the pool of PA3177-generated c-di-GMP only contributing to biofilm drug tolerance but not to biofilm formation.},
}
@article {pmid30081568,
year = {2018},
author = {Carbone, A and Parrino, B and Cusimano, MG and Spanò, V and Montalbano, A and Barraja, P and Schillaci, D and Cirrincione, G and Diana, P and Cascioferro, S},
title = {New Thiazole Nortopsentin Analogues Inhibit Bacterial Biofilm Formation.},
journal = {Marine drugs},
volume = {16},
number = {8},
pages = {},
doi = {10.3390/md16080274},
pmid = {30081568},
issn = {1660-3397},
abstract = {New thiazole nortopsentin analogues were conveniently synthesized and evaluated for their activity as inhibitors of biofilm formation of relevant Gram-positive and Gram-negative pathogens. All compounds were able to interfere with the first step of biofilm formation in a dose-dependent manner, showing a selectivity against the staphylococcal strains. The most active derivatives elicited IC50 values against Staphylococcus aureus ATCC 25923, ranging from 0.40⁻2.03 µM. The new compounds showed a typical anti-virulence profile, being able to inhibit the biofilm formation without affecting the microbial growth in the planktonic form.},
}
@article {pmid30080666,
year = {2018},
author = {Petruzzi, B and Dalloul, RA and LeRoith, T and Evans, NP and Pierson, FW and Inzana, TJ},
title = {Biofilm formation and avian immune response following experimental acute and chronic avian cholera due to Pasteurella multocida.},
journal = {Veterinary microbiology},
volume = {222},
number = {},
pages = {114-123},
doi = {10.1016/j.vetmic.2018.07.005},
pmid = {30080666},
issn = {1873-2542},
abstract = {Pasteurella multocida is the causative agent of avian cholera, an important economic and ecological disease that can present as a peracute, acute, chronic, or asymptomatic infection. Acute avian cholera is associated with encapsulated P. multocida, while chronic and asymptomatic cases of avian cholera may be associated with capsule-deficient P. multocida isolates. We hypothesize that biofilm formation is also associated with chronic and asymptomatic avian cholera. Experimental infections of chickens with encapsulated, biofilm-deficient P. multocida strain X73, proficient biofilm forming P. multocida strain X73ΔhyaD, and proficient biofilm forming clinical strains 775 and 756 showed that virulence was inversely correlated with biofilm formation. Biofilm-proficient isolates induced chronic avian cholera in the chicken host. Histopathological analysis was used to show that biofilm-proficient isolates induced little inflammation in the lungs, heart, and liver, while biofilm-deficient isolates induced greater inflammation and induced the recruitment of heterophil granulocytes. Putative biofilm matrix material and exopolysaccharide was detected in pulmonary tissue of chickens diagnosed with chronic avian cholera using scanning electron microscopy and a fluorescently-tagged lectin, respectively, supporting a role for biofilm in chronic avian cholera. P. multocida induced Th1 and Th17 immune responses during acute and chronic avian cholera, as determined by quantitative real-time PCR of splenic cytokine genes. Chickens that succumbed to acute avian cholera after experimental challenge with strain X73 had high levels of INF-γ, IL-1β, IL-6, IL-12A, IL-22, IL-17A, and IL-17RA expressed in the spleen compared to all other experimental groups. Birds infected with capsule-deficient strains had chronic infections lasting 7 days or longer, and had increased levels of IL-17RA, CCR6, and IL-16 compared to non-infected control chickens. However, specific antibody titers increased only transiently to capsule-deficient strains and were low, indicating that antibodies are less important in managing and clearing P. multocida infections.},
}
@article {pmid30080406,
year = {2018},
author = {Bogler, A and Bar-Zeev, E},
title = {Membrane distillation biofouling: Impact of feed water temperature on biofilm characteristics and membrane performance.},
journal = {Environmental science &amp; technology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.est.8b02744},
pmid = {30080406},
issn = {1520-5851},
abstract = {Membrane distillation (MD) is a temperature driven membrane separation technology that holds great potential for decentralized and sustainable wastewater treatment systems. Yet, similarly to all membrane based systems, microbial fouling (biofouling) might be a critical hurdle for MD wastewater treatment applications. In this study we determined the impact of increasing feed water temperatures (47 °C, 55 °C and 65 °C) on biofilm growth and MD performance via dynamic biofouling experiments with Anoxybacillus sp. as a model bacterium. Our results indicated that cell growth was reduced at 47 °C, resulting in moderate distillate water flux decline (30%). Differently, extensive growth of Anoxybacillus sp. at feed water temperature of 55 °C caused severe distillate water flux decline (78%). Additionally, biofouling induced membrane wetting, which facilitated the passage of bacteria cells and endospores through the membrane structure into the distillate. Although bacteria growth was impaired at feed water temperature of 65 °C, excessive production of EPS (compared to bacterial abundance) crippled membrane separation due to severe pore wetting. These results underline the importance of optimized operating conditions and development of anti-biofouling and anti-wetting membranes for successful implementation of MD in wastewater treatment with high biofouling propensity.},
}
@article {pmid30078968,
year = {2018},
author = {Elkhashab, THT and Adel, LA and Nour, MS and Mahran, M and Elkaffas, M},
title = {Association of intercellular adhesion gene A with biofilm formation in staphylococci isolates from patients with conjunctivitis.},
journal = {Journal of laboratory physicians},
volume = {10},
number = {3},
pages = {309-315},
doi = {10.4103/JLP.JLP_122_17},
pmid = {30078968},
issn = {0974-2727},
abstract = {BACKGROUND: There is a great negative impact of biofilm-mediated infection on patient health which necessitates the use of reliable methods for detecting biofilm producers.<br><br>AIMS: This study was done to determine biofilm-producing ability and the presence of intercellular adhesion gene A in clinical staphylococcal isolates and to assess the reliability of two phenotypic methods used for biofilm detection.<br><br>MATERIALS AND METHODS: Fifty staphylococcal strains were isolated from 100 conjunctival swabs from patients attended the Ophthalmology Outpatient Department of the Research Institute of Ophthalmology. Two phenotypic methods were used for detection of biofilm production; qualitative congo red agar (CRA); and quantitative microtiter plate. Polymerase chain reaction was used to determine the presence of icaA gene.<br><br>RESULTS: In Staph aureus, 60% were positive biofilm forming and 40% were negative biofilm forming by both phenotypic methods. All positive biofilm-forming isolates were positive for icaA gene production. In coagulase negative staph, 50% were positive biofilm forming and 50% were negative biofilm forming by both phenotypic methods. All positive biofilm-forming strains were positive for icaA gene. All negative cases by CRA and microtiter plate methods were negative for icaA gene except two isolates. All staphylococcal isolates were subjected to antibiotic susceptibility test to correlate biofilm formation with multidrug resistance in staph.<br><br>CONCLUSION: There is high significant correlation between icaA gene presence and biofilm forming ability; however, the biofilm-forming ability of some isolates in the absence of icaA gene highlights the importance of further genetic investigations of ica-independent biofilm formation mechanisms.},
}
@article {pmid30077168,
year = {2018},
author = {Vergine, P and Salerno, C and Berardi, G and Pollice, A},
title = {Sludge cake and biofilm formation as valuable tools in wastewater treatment by coupling Integrated Fixed-film Activated Sludge (IFAS) with Self Forming Dynamic Membrane BioReactors (SFD-MBR).},
journal = {Bioresource technology},
volume = {268},
number = {},
pages = {121-127},
doi = {10.1016/j.biortech.2018.07.120},
pmid = {30077168},
issn = {1873-2976},
abstract = {Two lab-scale Self Forming Dynamic Membrane BioReactors (SFD-MBR), equipped with 50 µm nylon meshes were set up and operated for the treatment of real municipal wastewater. Plastic carriers were added in one of the two bioreactors to generate a combination of the Integrated Fixed-film Activated Sludge (IFAS) and the SFD-MBR technologies. Overall, the two systems performed very well, achieving excellent effluent quality under steady state conditions and showing good resilience to extreme organic loading conditions. Continuous air scouring and periodical mesh cleaning by jet rinsing with tap water were effective in maintaining stable and high productivity (membrane flux around 67 L m2 h-1) over a period of 140 days. The application of the IFAS process resulted in lower production of excess sludge and improved denitrification. On the other hand, under the tested conditions the combined IFAS-SFD-MBR showed a higher tendency to mesh clogging with respect to the SFD-MBR.},
}
@article {pmid30077104,
year = {2018},
author = {Zhou, L and Xu, X and Xia, S},
title = {Effects of sulfate on simultaneous nitrate and selenate removal in a hydrogen-based membrane biofilm reactor for groundwater treatment: Performance and biofilm microbial ecology.},
journal = {Chemosphere},
volume = {211},
number = {},
pages = {254-260},
doi = {10.1016/j.chemosphere.2018.07.092},
pmid = {30077104},
issn = {1879-1298},
abstract = {Effects of sulfate on simultaneous nitrate and selenate removal in a hydrogen-based membrane biofilm reactor (MBfR) for groundwater treatment was identified with performance and biofilm microbial ecology. In whole operation, MBfR had almost 100% removal of nitration even with 50 mg mL-1 sulfate. Moreover, selenate degradation increased from 95% to approximate 100% with sulfate addition, indicating that sulfate had no obvious effects on nitrate degradation, and even partly promoted selenate removal. Short-term sulfate effect experiment further showed that Gibbs free energy of reduction (majority) and abiotic sulfide oxidation (especially between sulfate and selenate) contributed to degradable performance with sulfate. Microbial ecology showed that high percentage of Hydrogenophaga (≥75%) was one of the contributors for the stable and efficient nitrate degradation. Chemoheterotrophy (ratio>0.3) and dark hydrogen oxidation (ratio>0.3) were the majority of functional profile for biofilm in MBfR, and sulfate led to profiles of sulfate respiration and respiration of sulfur compounds in biofilm. Additionally, no special bacteria for selenate degradation was identified in biofilm microbial ecology, and selenate degradation was relied on Hydrogenophaga (75% of ecology percentage with sulfate addition) and Desulfovibrionaceae (4% of ecology percentage with sulfate addition). But with overloading sulfate, Desulfovibrionaceae was prior to sulfate degradation for energy supply and thus inhibited selenate removal.},
}
@article {pmid30075862,
year = {2018},
author = {Zhang, P and Chen, YP and Qiu, JH and Dai, YZ and Feng, B},
title = {Imaging the Microprocesses in Biofilm Matrices.},
journal = {Trends in biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.tibtech.2018.07.006},
pmid = {30075862},
issn = {1879-3096},
abstract = {Biofilms, which are aggregates of microorganisms and extracellular matrices, widely colonize natural water bodies, wastewater treatment systems, and body tissues, and have vital roles in water purification, biofouling, and infectious diseases. Recently, multiple imaging modalities have been developed to visualize the morphological structure and material distribution within biofilms and to probe the microprocesses in biofilm matrices, including biofilm formation, transfer and metabolism of substrates, and cell-cell communication. These technologies have improved our understanding of biofilm control and the fates of substrates in biofilms. In this review, we describe the principles of various imaging techniques and discuss the advantages and limitations of each approach to characterizing microprocesses in biofilm matrices.},
}
@article {pmid30074210,
year = {2018},
author = {Wang, TM and Xie, XH and Li, K and Deng, YH and Chen, H},
title = {Alternative Oxidase Promotes Biofilm Formation of Candida albicans.},
journal = {Current medical science},
volume = {38},
number = {3},
pages = {443-448},
doi = {10.1007/s11596-018-1898-x},
pmid = {30074210},
issn = {2523-899X},
abstract = {This study was designed to analyze the effect of the mitochondrial respiratory pathways of Candida albicans (C. albicans) on the biofilm formation. The 2, 3-bis (2-methoxy- 4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay was used to measure the metabolic activities of biofilms formed by the C. albicans which were cultured in the presence of respiratory pathways inhibitors. The biofilms formed by the wide type (WT), GOA7-deleted (GOA31), GOAV-reconstituted (GOA32), AOXla-deleted (AOX1) and AOXlb-deleted (AOX2) C. albicans strains were examined by the XTT reduction assay and fluorescence microscopy. The expression of adhesion-related genes BCR1, ALS1, ALS3, ECE1 and HWP1 in the biofilms formed by the above five C. albicans strains was detected by real time polymerase chain reaction. It was found that the metabolic activity of biofilms formed by C. albicans was decreased in the presence of alternative oxidase inhibitor whereas it was increased in the presence of classical mitochondrial respiratory pathway complex HI or complex IV inhibitor. AOX1 strain produced scarce biofilms interspersed with few hyphal filaments. Moreover, no significant changes in the expression of BCR1 and ALS3 were observed in the AOX1 strain, but the expression of ALSI and ECE1 was down-regulated, and that of HWP1 was up-regulated. These results indicate that both AOX1 and AOX2 can promote the biofilm formation. However, AOXla primarily plays a regulatory role in biofilm formation in the absence of inducers where the promoting effect is mainly achieved by promoting mycelial formation.},
}
@article {pmid30073749,
year = {2018},
author = {Bae, N and Park, HJ and Park, H and Kim, M and Han, SW},
title = {Deciphering the functions of the outer membrane porin OprBXo involved in virulence, motility, exopolysaccharide production, biofilm formation, and stress tolerance in Xanthomonas oryzae pv. oryzae.},
journal = {Molecular plant pathology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mpp.12727},
pmid = {30073749},
issn = {1364-3703},
abstract = {Xanthomonas oryzae pv. oryzae (Xoo) is a Gram-negative bacterium causing bacterial leaf blight disease in rice. Previously, proteomic analysis had shown that outer membrane protein B in Xoo (OprBXo) was more abundant in the wildtype strain compared to the outer membrane protein 1 in Xoo (Omp1X)-knockout mutant. OprBXo shows high homology with OprB, which has been well characterized as a carbohydrate-selective porin in X. citri subsp. citri and Pseudomonas species. However, the functions of OprBXo in Xoo have not yet been documented. To elucidate the functions of OprBXo, we generated OprBXo-overexpressing mutant, Xoo(OprBXo), and knockout mutant, XooΔoprBXo(EV). We found that the virulence and migration of Xoo(OprBXo), but not XooΔoprBXo(EV), was markedly reduced in rice. To postulate the mechanisms affected by OprBXo, comparative proteomics analysis were performed. Based on the results of proteomics, we employed diverse phenotypic assays to characterize the functions of OprBXo. Abnormal twitching motility and reduction of swarming motility were observed in Xoo(OprBXo). Moreover, Xoo(OprBXo) decreased, but XooΔoprBXo(EV) enhanced, exopolysaccharide production and biofilm formation. The chemotactic ability of XooΔoprBXo(EV) was dramatically lower than that of Xoo(EV) in the presence of glucose and xylose. Xoo(OprBXo) was resistant to sodium dodecyl sulfate and hydrogen peroxide, but XooΔoprBXo(EV) was highly sensitive compared to Xoo(EV). Thus, OprBXo is not only essential for chemotaxis and stress tolerance, but also for motility, biofilm formation, and exopolysaccharide production, which may contribute to the virulence of Xoo. These results will lead to new insights into the functions of a sugar-selective porin in Xoo. This article is protected by copyright. All rights reserved.},
}
@article {pmid30073039,
year = {2018},
author = {Almeida, CA and Azevedo, MMB and Chaves, FCM and Roseo de Oliveira, M and Rodrigues, IA and Bizzo, HR and Gama, PE and Alviano, DS and Alviano, CS},
title = {Piper Essential Oils Inhibit Rhizopus oryzae Growth, Biofilm Formation, and Rhizopuspepsin Activity.},
journal = {The Canadian journal of infectious diseases &amp; medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale},
volume = {2018},
number = {},
pages = {5295619},
doi = {10.1155/2018/5295619},
pmid = {30073039},
issn = {1712-9532},
abstract = {Piper is the largest genus of the Piperaceae family. The species of this genus have diverse biological activities and are used in pharmacopeia throughout the world. They are also used in folk medicine for treatment of many diseases in several countries including Brazil, China, India, Jamaica, and Mexico. In Brazil, Piper species are distributed throughout the national territory, making this genus a good candidate for biological activity screening. During our studies with Piper essential oils, we evaluated its activity against Rhizopus oryzae, the main agent of mucormycosis. The main compounds of seven Piper essential oils analyzed were Piper callosum-safrole (53.8%), P. aduncum-dillapiole (76.0%), P. hispidinervum-safrole (91.4%), P. marginatum-propiopiperone (13.2%), P. hispidum-γ-terpinene (30.9%), P. tuberculatum-(E)-caryophyllene (30.1%), and Piper sp.-linalool (14.6%). The minimum inhibitory concentration of Piper essential oils against R. oryzae ranged from 78.12 to >1250 μg/mL. The best result of total inhibition of biofilm formation was obtained with Piper sp. starting from 4.88 μg/mL. Considering the bioactive potential of EOs against planktonic cells and biofilm formation of R. oryzae could be of great interest for development of antimicrobials for therapeutic use in treatment of fungal infection.},
}
@article {pmid30071459,
year = {2018},
author = {Ooi, GTH and Tang, K and Chhetri, RK and Kaarsholm, KMS and Sundmark, K and Kragelund, C and Litty, K and Christensen, A and Lindholst, S and Sund, C and Christensson, M and Bester, K and Andersen, HR},
title = {Biological removal of pharmaceuticals from hospital wastewater in a pilot-scale staged moving bed biofilm reactor (MBBR) utilising nitrifying and denitrifying processes.},
journal = {Bioresource technology},
volume = {267},
number = {},
pages = {677-687},
doi = {10.1016/j.biortech.2018.07.077},
pmid = {30071459},
issn = {1873-2976},
abstract = {Hospital wastewater contains high concentrations of pharmaceuticals, which pose risks to receiving waters. In this study, a pilot plant consisting of six moving bed biofilm reactors (MBBRs) in series (with the intention to integrate Biological Oxygen Demand (BOD) removal, nitrification and denitrification as well as prepolishing Chemical Oxygen Demand (COD) for ozonation) was built to integrate pharmaceutical removal and intermittent feeding of the latter reactors aimed for micropollutant removal. Based on the experimental resultss, nitrifying MBBRs achieved higher removal as compared to denitrifying MBBRs except for azithromycin, clarithromycin, diatrizoic acid, propranolol and trimethoprim. In the batch experiments, nitrifying MBBRs showed the ability to remove most of the analysed pharmaceuticals, with degradation rate constants ranging from 5.0 × 10-3 h-1 to 2.6 h-1. In general, the highest degradation rate constants were observed in the nitrifying MBBRs while the latter MBBRs showed lower degradation rate constant. However, when the degradation rate constants were normalised to the respective biomass, the intermittently fed reactors presented the highest specific activity. Out of the 22 compounds studied, 17 compounds were removed with more than 20%.},
}
@article {pmid30071451,
year = {2018},
author = {Rekha, R and Vaseeharan, B and Ishwarya, R and Anjugam, M and S Alharbi, N and Kadaikunnan, S and Khaled, JM and Al-Anbr, MN and Govindarajan, M},
title = {Searching for crab-borne antimicrobial peptides: Crustin from Portunus pelagicus triggers biofilm inhibition and immune responses of Artemia salina against GFP tagged Vibrio parahaemolyticus Dahv2.},
journal = {Molecular immunology},
volume = {101},
number = {},
pages = {396-408},
doi = {10.1016/j.molimm.2018.07.024},
pmid = {30071451},
issn = {1872-9142},
abstract = {Marine organisms represent a huge source of novel compounds for the development of effective antimicrobial drugs. The present study focus on the purification of the antimicrobial peptide crustin from the haemolymph of the blue swimmer crab, Portunus pelagicus, by blue Sepharose CL-6B matrix assisted affinity column chromatography. Crustin showed a single band with a molecular mass of 17 kDa in SDS-PAGE analysis. The XRD analysis exhibited peaks at 32° and 45° while a distinct peak with a retention time of 1.8 min resulted in high performance liquid chromatography (HPLC) pointing out the crystalline nature and purity of crustin, respectively. Crustin purified from P. pelagicus (Pp-Cru) showed immunological activities, triggering encapsulation, phagocytosis on Sepharose beads and yeast (Saccharomyces cerevisiae) respectively. Furthermore, encapsulation of GFP tagged V. parahaemolyticus in Artemia salina and challenging study were assessed under CLSM and the potential of Pp-Cru was examined in vivo. In addition, the growth reduction and biofilm inhibition potential of Pp-Cru on Staphylococcus aureus, Enterococcus faecalis (Gram- positive bacteria) and Pseudomonas aeruginosa, Escherichia coli (Gram-negative bacteria) was evidenced by inverted and confocal laser scanning microscopic analysis, revealing that 100 μg/ml of Pp-Cru can disrupt the biofilm matrix thereby the thickness of biofilm was significantly reduced. Overall, the present investigation might provide a sensitive platform to realize the significant function of Pp-Cru in crustacean immune mechanism as well as its potential to bacterial growth inhibitor. The functional properties of purified Pp-Cru antimicrobial peptide may lead to a superior understanding of innate immune response in P. pelagicus species, which suggest the promising application for drug development in aquaculture.},
}
@article {pmid30070706,
year = {2018},
author = {Souza, JGS and Cury, JA and Ricomini-Filho, AP and Feres, M and de Faveri, M and Barão, VAR},
title = {Effect of sucrose on biofilm formed in situ on titanium material.},
journal = {Journal of periodontology},
volume = {},
number = {},
pages = {},
doi = {10.1002/JPER.18-0219},
pmid = {30070706},
issn = {1943-3670},
abstract = {BACKGROUND: Since sucrose may change the composition of biofilms formed on dental surfaces, the aim of this study was to evaluate in situ the effect of this dietary sugar on biofilm formation on titanium surface.<br><br>MATERIALS AND METHODS: In this blind, crossover, in situ study, 10 volunteers wore, in 3 phases of 7 days each, a palatal appliance containing titanium specimens. In each phase, the specimens were treated extraorally with 20% sucrose solution at a frequency of 4 or 8 times per day. As control, no treatment was rendered (0 ×). At the end of each phase, the biofilms were collected for biochemical analysis of biofilm wet weight (biomass), protein concentration, soluble (S-EPS) and insoluble (I-EPS) extracellular polysaccharides and intracellular polysaccharides (IPS), and for microbiological analysis by checkerboard DNA-DNA hybridization (for levels and proportions of 40 bacterial species). Biochemical data were analyzed by linear regression and microbiological findings by Friedman and Dunn tests (α = .05).<br><br>RESULTS: A positive significant linear relationship was found among sucrose exposure (0 ×, 4 × and 8 ×) and biomass, S-EPS, I-EPS and IPS (p < .05). The biofilms treated with sucrose (4 × and/or 8 ×) presented higher mean total levels of the 40 bacterial species evaluated, higher proportions of red complex species and lower proportions of the host-compatible green complex species, in comparison with the control group (p < .05).<br><br>CONCLUSION: The findings of the present study suggest that daily sucrose exposure has a harmful effect on the composition of biofilms formed on titanium surfaces. This article is protected by copyright. All rights reserved.},
}
@article {pmid30070287,
year = {2018},
author = {Kuppusamy, R and Yasir, M and Yee, E and Willcox, M and Black, DS and Kumar, N},
title = {Guanidine functionalized anthranilamides as effective antibacterials with biofilm disruption activity.},
journal = {Organic &amp; biomolecular chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1039/c8ob01699b},
pmid = {30070287},
issn = {1477-0539},
abstract = {We describe a library of amphiphilic anthranilamide compounds as antimicrobial peptide (AMP) mimics. These contain a hydrophobic naphthoyl side chain and different hydrophilic cationic groups such as amino, quaternary ammonium and guanidino groups. These are prepared via the ring-opening of different isatoic anhydrides. The antibacterial activity against S. aureus and E. coli of compounds containing guanidino cationic groups was greater than that for amino and quaternary ammonium cationic groups. The fluoro-substituted guanidinium compound 9b showed a minimum inhibitory concentration (MIC) of 2.0 μM against S. aureus, and reduced established biofilms of S. aureus by 92% at 64 μM concentration. The bromo-substituted guanidinium compound 9d exhibited good MIC against S. aureus (3.9 μM) and E. coli (15.6 μM) and disrupted established biofilms of S. aureus by 83% at 62.4 μM concentration. Cytoplasmic membrane permeability studies suggested that depolarization and disruption of the bacterial cell membrane could be a possible mechanism for antibacterial activity and the in vitro toxicity studies against MRC-5 human lung fibroblast cells showed that the potent compounds are non-toxic against mammalian cells.},
}
@article {pmid30070146,
year = {2018},
author = {Konieczka, P and Nowicka, K and Madar, M and Taciak, M and Smulikowska, S},
title = {Effects of pea extrusion and enzyme and probiotic supplementation on performance, microbiota activity and biofilm formation in the broiler gastrointestinal tract.},
journal = {British poultry science},
volume = {},
number = {},
pages = {},
doi = {10.1080/00071668.2018.1507017},
pmid = {30070146},
issn = {1466-1799},
abstract = {1. The effects of supplementation of broiler chicken diets with pea meal, carbohydrase enzymes and a probiotic were investigated for potential performance improvement. 2. Raw or extruded pea meal (cv Model, grown in Poland) was included in a wheat-soybean meal-based diet at 250 g/kg. The diets were unsupplemented (control) or supplemented with either carbohydrase enzymes (200 U/kg xylanase and 10 U/kg β-glucanase in feed) or a probiotic (Bacillus subtilis), or both. The diets were fed to Ross 308 broilers aged nine to 28 days. 3. After two additional days, chick gastrointestinal tracts were excised and analysed for the presence of Bacillus subtilis biofilm; and the ileal and caecal digesta were analysed for bacterial enzyme activities and to determine the concentration of short-chain fatty acids (SCFAs). 4. Feeding the pea-based diet supplemented with the probiotic compromised feed utilisation, due to higher feed intake. The addition of enzymes to the raw, but not the extruded, pea containing diet partially ameliorated this effect (pea form x additives; P<0.002). 5. In the ileal digesta, interactions between the dietary treatments were observed for the activities of all bacterial glycolytic enzymes and for SCFA concentrations. β-glucosidase, α-galactosidase and β-glucuronidase were highest in birds fed the diet containing extruded pea supplemented with the probiotic and enzymes (pea form x additives; P <0.018 to P<0.006). In the caecal digesta, interactions were observed for bacterial enzyme activities, but not for total SCFA concentration. Biofilm formation in the caecum indicated that the probiotic strain was metabolically active in the broiler gut. 6. In conclusion, supplementation of diets containing raw or extruded pea meal with enzymes and a Bacillus subtilis spore-based probiotic modulated microbiota activity but had no clear effects on broiler performance. Probiotic administration did not cause excessive fermentation in the ileum and caecum but enhanced Bacillus subtilis spp. biofilm formation in the caecum, which may be indicative of a beneficial effect on gut health.},
}
@article {pmid30069474,
year = {2018},
author = {Woo, SH and Lee, SM and Park, KC and Park, GN and Cho, B and Kim, I and Kim, J and Hong, S},
title = {Effects of Fine Particulate Matter on Pseudomonas aeruginosa Adhesion and Biofilm Formation In Vitro.},
journal = {BioMed research international},
volume = {2018},
number = {},
pages = {6287932},
doi = {10.1155/2018/6287932},
pmid = {30069474},
issn = {2314-6141},
abstract = {Respiratory infections of Pseudomonas aeruginosa are a major cause of mortality and morbidity for hospitalized patients. Fine particulate matter (FPM) is known to have interactions with some bacterial infection in the respiratory system. In this report, we investigate the effect of different concentration of FPM on P. aeruginosa attachment and biofilm formation using in vitro cell culture systems. P. aeruginosa were cultured to form mature biofilms on hydroxyapatite-coated peg and the number of bacteria in the biofilms was enumerated. Morphology of biofilm was imaged with scanning electron microscopy and confocal laser scanning microscopy. Bacterial affinity change to the cell membrane was evaluated with attached colony counting and fluorescence microscopy images. Alteration of bacterial surface hydrophobicity and S100A4 protein concentration were explored as mechanisms of P. aeruginosa adhesion to human cells. There were a concentration-dependent increase of thickness and surface roughness of biofilm mass. P. aeruginosa adherence to respiratory epithelial cells was increased after FPM treatment. Bacterial surface hydrophobicity and S1000A4 protein concentration were increased with proportionally the dose of FPM in media. FPM in the airway could enhance both the adhesion of P. aeruginosa to epithelial cells and biofilm formation. Bacterial surface hydrophobicity and human cell plasma membrane injury are associated with binding of P. aeruginosa on airway epithelial cells and biofilm formation.},
}
@article {pmid30068935,
year = {2018},
author = {Garcia, C and Burgain, A and Chaillot, J and Pic, É and Khemiri, I and Sellam, A},
title = {A phenotypic small-molecule screen identifies halogenated salicylanilides as inhibitors of fungal morphogenesis, biofilm formation and host cell invasion.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {11559},
doi = {10.1038/s41598-018-29973-8},
pmid = {30068935},
issn = {2045-2322},
support = {&amp;#x00C9;tablissement de jeunes chercheurs//Fonds de Recherche du Qu&amp;#x00E9;bec - Sant&amp;#x00E9; (Fonds de la recherche en sante du Quebec)/ ; J1 salary award//Fonds de Recherche du Qu&amp;#x00E9;bec - Sant&amp;#x00E9; (Fonds de la recherche en sante du Quebec)/ ; Discovery grant #06625//Gouvernement du Canada | Natural Sciences and Engineering Research Council of Canada (Conseil de Recherches en Sciences Naturelles et en G&amp;#x00E9;nie du Canada)/ ; CFI- # 34171//Canada Foundation for Innovation (Fondation canadienne pour l&amp;apos;innovation)/ ; },
abstract = {A poorly exploited paradigm in the antimicrobial therapy field is to target virulence traits for drug development. In contrast to target-focused approaches, antivirulence phenotypic screens enable identification of bioactive molecules that induce a desirable biological readout without making a priori assumption about the cellular target. Here, we screened a chemical library of 678 small molecules against the invasive hyphal growth of the human opportunistic yeast Candida albicans. We found that a halogenated salicylanilide (N1-(3,5-dichlorophenyl)-5-chloro-2-hydroxybenzamide) and one of its analogs, Niclosamide, an FDA-approved anthelmintic in humans, exhibited both antifilamentation and antibiofilm activities against C. albicans and the multi-resistant yeast C. auris. The antivirulence activity of halogenated salicylanilides were also expanded to C. albicans resistant strains with different resistance mechanisms. We also found that Niclosamide protected the intestinal epithelial cells against invasion by C. albicans. Transcriptional profiling of C. albicans challenged with Niclosamide exhibited a signature that is characteristic of the mitochondria-to-nucleus retrograde response. Our chemogenomic analysis showed that halogenated salicylanilides compromise the potential-dependant mitochondrial protein translocon machinery. Given the fact that the safety of Niclosamide is well established in humans, this molecule could represent the first clinically approved antivirulence agent against a pathogenic fungus.},
}
@article {pmid30067078,
year = {2018},
author = {Marchese, A and Arciola, CR and Coppo, E and Barbieri, R and Barreca, D and Chebaibi, S and Sobarzo-Sánchez, E and Nabavi, SF and Nabavi, SM and Daglia, M},
title = {The natural plant compound carvacrol as an antimicrobial and anti-biofilm agent: mechanisms, synergies and bio-inspired anti-infective materials.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-27},
doi = {10.1080/08927014.2018.1480756},
pmid = {30067078},
issn = {1029-2454},
abstract = {Carvacrol (5-isopropyl-2-methyl phenol) is a natural compound that occurs in the leaves of a number of plants and herbs including wild bergamot, thyme and pepperwort, but which is most abundant in oregano. The aim of this review is to analyse the scientific data from the last five years (2012-2017) on the antimicrobial and anti-biofilm activities of carvacrol, targeting different bacteria and fungi responsible for human infectious diseases. The antimicrobial and anti-biofilm mechanisms of carvacrol and its synergies with antibiotics are illustrated. The potential of carvacrol-loaded anti-infective nanomaterials is underlined. Carvacrol shows excellent antimicrobial and anti-biofilm activities, and is a very interesting bioactive compound against fungi and a wide range of Gram-positive and Gram-negative bacteria, and being active against both planktonic and sessile human pathogens. Moreover, carvacrol lends itself to being combined with nanomaterials, thus providing an opportunity for preventing biofilm-associated infections by new bio-inspired, anti-infective materials.},
}
@article {pmid30066983,
year = {2018},
author = {Obuobi, S and Wang, Y and Khara, J and Riegger, A and Kuan, SL and Ee, PLR},
title = {Antimicrobial and Anti-Biofilm Activities of Surface Engineered Polycationic Albumin Nanoparticles with Reduced Hemolytic Activity.},
journal = {Macromolecular bioscience},
volume = {},
number = {},
pages = {e1800196},
doi = {10.1002/mabi.201800196},
pmid = {30066983},
issn = {1616-5195},
abstract = {Protein-based polymeric polyelectrolytes are emerging as alternative synthetic nanoparticles owing to their biodegradability and biocompatibility. However, potential in vivo toxicity remains a significant challenge. Herein an array of protein polyelectrolytes generated from cationic human serum albumin (cHSA) and polyethylene glycol (PEG) are synthesized via synthetic customization as antimicrobials for the treatment of systemic infections. By varying PEG molecular weight and chain length, in vitro hemolytic activity can be fine-tuned without significantly affecting antimicrobial potency. The optimal hybrid material, PEG (2000)18 -cHSA, with potent antimicrobial character, low hemolytic activity, and in vitro biofilm disruptive properties is identified. Surface plasmon resonance (SPR) evaluation demonstrates significantly higher binding activity of the protein nanoparticles to bacteria cell wall components and microfluidic live-cell imaging indicates that the nanoparticles act through a membranolytic mechanism. Given their low susceptibility to drug resistance and potent activity against resistant bacteria strains, these findings establish the PEGylated albumin nanoparticles as a potent weaponry against drug resistance and biofilm-related infection.},
}
@article {pmid30066753,
year = {2018},
author = {Santos, ALSD and Galdino, ACM and Mello, TP and Ramos, LS and Branquinha, MH and Bolognese, AM and Columbano Neto, J and Roudbary, M},
title = {What are the advantages of living in a community? A microbial biofilm perspective!.},
journal = {Memorias do Instituto Oswaldo Cruz},
volume = {113},
number = {9},
pages = {e180212},
doi = {10.1590/0074-02760180212},
pmid = {30066753},
issn = {1678-8060},
abstract = {Biofilm formation is the preferred mode of growth lifestyle for many microorganisms, including bacterial and fungal human pathogens. Biofilm is a strong and dynamic structure that confers a broad range of advantages to its members, such as adhesion/cohesion capabilities, mechanical properties, nutritional sources, metabolite exchange platform, cellular communication, protection and resistance to drugs (e.g., antimicrobials, antiseptics, and disinfectants), environmental stresses (e.g., dehydration and ultraviolet light), host immune attacks (e.g., antibodies, complement system, antimicrobial peptides, and phagocytes), and shear forces. Microbial biofilms cause problems in the hospital environment, generating high healthcare costs and prolonged patient stay, which can result in further secondary microbial infections and various health complications. Consequently, both public and private investments must be made to ensure better patient management, as well as to find novel therapeutic strategies to circumvent the resistance and resilience profiles arising from biofilm-associated microbial infections. In this work, we present a general overview of microbial biofilm formation and its relevance within the biomedical context.},
}
@article {pmid30065702,
year = {2018},
author = {Rehman, ZU and Leiknes, T},
title = {Quorum-Quenching Bacteria Isolated From Red Sea Sediments Reduce Biofilm Formation by Pseudomonas aeruginosa.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1354},
doi = {10.3389/fmicb.2018.01354},
pmid = {30065702},
issn = {1664-302X},
abstract = {Quorum sensing (QS) is the process by which bacteria communicate with each other through small signaling molecules such as N-acylhomoserine lactones (AHLs). Certain bacteria can degrade AHL molecules by a process called quorum quenching (QQ); therefore, QQ can be used to control bacterial infections and biofilm formation. In this study, we aimed to identify new species of bacteria with QQ activity. Red Sea sediments were collected either from the close vicinity of seagrass or from areas with no vegetation. We isolated 72 bacterial strains, which were tested for their ability to degrade/inactivate AHL molecules. Chromobacterium violaceum CV026-based bioassay was used for the initial screening of isolates with QQ activity. QQ activity was further quantified using high-performance liquid chromatography-tandem mass spectrometry. We found that these isolates could degrade AHL molecules of different acyl chain lengths as well as modifications. 16S-rRNA sequencing of positive QQ isolates showed that they belonged to three different genera. Specifically, two isolates belonged to the genus Erythrobacter; four, Labrenzia; and one, Bacterioplanes. The genome of one representative isolate from each genus was sequenced, and potential QQ enzymes, namely, lactonases and acylases, were identified. The ability of these isolates to degrade the 3OXOC12-AHLs produced by Pseudomonas aeruginosa PAO1 and hence inhibit biofilm formation was investigated. Our results showed that the isolate VG12 (genus Labrenzia) is better than other isolates at controlling biofilm formation by PAO1 and degradation of different AHL molecules. Time-course experiments to study AHL degradation showed that VG1 (genus Erythrobacter) could degrade AHLs faster than other isolates. Thus, QQ bacteria or enzymes can be used in combination with an antibacterial to overcome antibiotic resistance.},
}
@article {pmid30062880,
year = {2018},
author = {Funari, R and Bhalla, N and Chu, KY and Söderström, B and Shen, AQ},
title = {Nanoplasmonics for real-time and label-free monitoring of microbial biofilm formation.},
journal = {ACS sensors},
volume = {},
number = {},
pages = {},
doi = {10.1021/acssensors.8b00287},
pmid = {30062880},
issn = {2379-3694},
abstract = {Microbial biofilms possess intrinsic resistance against conventional antibiotics and cleaning procedures, thus a better understanding of their complex biological structures is crucial in both medical and industrial applications. Existing laboratory methodologies have focused on macroscopic and mostly indirect characterization of mechanical and microbiological properties of biofilms adhered on a given substrate. However, the kinetics underlying the biofilm formation is not well understood, while such information is critical to understand how drugs and chemicals influence the biofilm formation. Herein, we report the use of localized surface plasmon resonance (LSPR) for real-time, label-free monitoring of \textit{E. coli}
biofilm assembly on a nanoplasmonic substrate consisting of gold mushroom-like structures. Our LSPR sensor is able to capture the signatures of biofilm formation in real-time by measuring the wavelength shift in the LSPR resonance peak with high temporal resolution. We employ this sensor feature to elucidate how biofilm formation is affected by different drugs, including conventional antibiotics (kanamycin and ampicillin) as well as rifapentine, a molecule preventing cell adhesion yet barely affecting bacterial viability and vitality. Due to its flexibility and simplicity, our LSPR based platform can be used on a wide variety of clinically relevant bacteria, thus representing a valuable tool in biofilm characterization and drug screening.},
}
@article {pmid30062620,
year = {2018},
author = {Paldrychová, M and Kolouchová, I and Vaňková, E and Maťátková, O and Šmidrkal, J and Krmela, A and Schulzová, V and Hajšlová, J and Masák, J},
title = {Effect of resveratrol and Regrapex-R-forte on Trichosporon cutaneum biofilm.},
journal = {Folia microbiologica},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12223-018-0633-0},
pmid = {30062620},
issn = {1874-9356},
support = {17-15936S//Grantová Agentura České Republiky/ ; CZ.2.16/3.1.00/24503//Operational Programme Prague - Competitiveness/ ; NPU I (LO1601 - No.: MSMT-43760/2015)//National Program of Sustainability I/ ; },
abstract = {Microorganisms that cause chronic infections exist predominantly as surface-attached stable communities known as biofilms. Microbial cells in biofilms are highly resistant to conventional antibiotics and other forms of antimicrobial treatment; therefore, modern medicine tries to develop new drugs that exhibit anti-biofilm activity. We investigated the influence of a plant polyphenolic compound resveratrol (representative of the stilbene family) on the opportunistic pathogen Trichosporon cutaneum. Besides the influence on the planktonic cells of T. cutaneum, the ability to inhibit biofilm formation and to eradicate mature biofilm was studied. We have tested resveratrol as pure compound, as well as resveratrol in complex plant extract-the commercially available dietary supplement Regrapex-R-forte, which contains the extract of Vitis vinifera grape and extract of Polygonum cuspidatum root. Regrapex-R-forte is rich in stilbenes and other biologically active substances. Light microscopy imaging, confocal microscopy, and crystal violet staining were used to quantify and visualize the biofilm. The metabolic activity of biofilm-forming cells was studied by the tetrazolium salt assay. Amphotericin B had higher activity against planktonic cells; however, resveratrol and Regrapex-R-forte showed anti-biofilm effects, both in inhibition of biofilm formation and in the eradication of mature biofilm. The minimum biofilm eradicating concentration (MBEC80) for Regrapex-R-forte was found to be 2222 mg/L (in which resveratrol concentration is 200 mg/L). These methods demonstrated that Regrapex-R-forte can be employed as an anti-biofilm agent, as it has similar effect as amphotericin B (MBEC80 = 700 mg/L), which is routinely used in clinical practice.},
}
@article {pmid30062140,
year = {2018},
author = {Abi Hachem, R and Goncalves, S and Walker, T and Angeli, S},
title = {Middle ear irrigation using a hydrodebrider decreases biofilm surface area in an animal model of otitis media.},
journal = {Laryngoscope investigative otolaryngology},
volume = {3},
number = {3},
pages = {231-237},
doi = {10.1002/lio2.164},
pmid = {30062140},
issn = {0023-852X},
abstract = {Objective: To compare the safety and efficacy of manual and powered irrigation of the middle ear using saline or 1% baby shampoo to treat biofilm-forming bacterial middle ear infections.<br><br>Background: Biofilms play a major role in recalcitrant otitis media and are challenging to treat. Many therapeutic strategies have been attempted and the role of topical therapies is still being investigated. Topical irrigation using saline or 1% baby shampoo and the use of a hydrodebrider have been investigated in biofilms involved in chronic rhinosinusitis and their role within the middle ear is yet to be determined.<br><br>Methods: Twenty-two adult chinchillas underwent bilateral trans-bullar inoculation of non-typable biofilm forming Haemophilus influenza followed by unilateral middle ear irrigation 5 days later using saline administered via a powered hydrodebrider or manual irrigation of saline or 1% baby shampoo. Contralateral inoculated ears served as control and were not irrigated. Two days following irrigation, the bullae were harvested and processed for scanning electron microscopy to assess biofilm surface area. Auditory brainstem responses were performed before bacterial inoculation and prior to euthanasia.<br><br>Results: Manual and powered irrigation were effective in reducing the surface area of biofilm when compared to the control group. The hydrodebrider demonstrated to be more effective at eradicating biofilm than manual irrigation, especially in areas of difficult access, such as the ventral portion of the chinchillas' bullae. There was no difference in manual irrigation of saline when compared to 1% baby shampoo. Irrigations either manually or using the hydrodebrider did not affect hearing, the vestibular system or facial function.<br><br>Conclusion: Middle ear biofilms can be treated safely and effectively with rinses using either normal saline or 1% baby shampoo administered manually or with a powered hydrodebrider.<br><br>Level of Evidence: NA.},
}
@article {pmid30061756,
year = {2018},
author = {Kent, AG and Garcia, CA and Martiny, AC},
title = {Increased biofilm formation due to high-temperature adaptation in marine Roseobacter.},
journal = {Nature microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41564-018-0213-8},
pmid = {30061756},
issn = {2058-5276},
abstract = {Ocean temperatures will increase significantly over the next 100 years due to global climate change1. As temperatures increase beyond current ranges, it is unclear how adaptation will impact the distribution and ecological role of marine microorganisms2. To address this major unknown, we imposed a stressful high-temperature regime for 500 generations on a strain from the abundant marine Roseobacter clade. High-temperature-adapted isolates significantly improved their fitness but also increased biofilm formation at the air-liquid interface. Furthermore, this altered lifestyle was coupled with genomic changes linked to biofilm formation in individual isolates, and was also dominant in evolved populations. We hypothesize that the increasing biofilm formation was driven by lower oxygen availability at elevated temperature, and we observe a relative fitness increase at lower oxygen. The response is uniquely different from that of Escherichia coli adapted to high temperature3 (only 3% of mutated genes were shared in both studies). Thus, future increased temperatures could have a direct effect on organismal physiology and an indirect effect via a decrease in ocean oxygen solubility, leading to an alteration in microbial lifestyle.},
}
@article {pmid30061582,
year = {2018},
author = {Takimoto, Y and Hatamoto, M and Ishida, T and Watari, T and Yamaguchi, T},
title = {Fouling Development in A/O-MBR under Low Organic Loading Condition and Identification of Key Bacteria for Biofilm Formations.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {11427},
doi = {10.1038/s41598-018-29821-9},
pmid = {30061582},
issn = {2045-2322},
abstract = {Membrane fouling in membrane bioreactors (MBR) remains a major issue and knowledge of microbes associated with biofilm formation might facilitate the control of this phenomenon, Thus, an anoxic/oxic membrane bioreactor (A/O-MBR) was operated under an extremely low organic loading rate (0.002 kg-COD·m-3·day-1) to induce membrane fouling and the major biofilm-forming bacteria were identified. After operation under extremely low organic loading condition, the reactor showed accumulation of total nitrogen and phosphorus along with biofilm development on the membrane surface. Thus, membrane fouling induced by microbial cell lysis was considered to have occurred. Although no major changes were observed in the microbial community structure of the activated sludge in the MBR before and after membrane fouling, uncultured bacteria were specifically increased in the biofilm. Therefore, bacteria belonging to candidate phyla including TM6, OD1 and Gammaproteobacteria could be important biofilm-forming bacteria.},
}
@article {pmid30060425,
year = {2018},
author = {Yang, JX and Zhao, B and An, Q and Huang, YS and Guo, JS},
title = {Bioaugmentation with A. faecalis strain NR for achieving simultaneous nitrogen and organic carbon removal in a biofilm reactor.},
journal = {Bioresource technology},
volume = {247},
number = {},
pages = {871-880},
doi = {10.1016/j.biortech.2017.09.189},
pmid = {30060425},
issn = {1873-2976},
abstract = {The dynamics model of Alcaligenes faecalis NR was combined with the activated sludge model No. 1 to guide how to make the bioaugmentation of strain NR successful. Model studies show that conventional heterotrophic bacteria in activated sludge always outcompete strain NR. The competition between strain NR and Nitrosomonas, a typical ammonium-oxidizing bacterium (AOB), mainly depends on COD concentration and maximum growth rate of Nitrosomonas. 2000mg/L of COD ensures that strain NR is always able to outcompete AOB. A biofilm reactor was developed to avoid a quick decrease in influent substrates. Approximately 94.2% of TN and 93.6% of COD were removed in the bioaugmented biofilm reactor, showing much better performance than an identical biofilm reactor without strain NR inoculation. A long-term experiment showed that strain NR successfully proliferated in the bioaugmented reactor. The abundance variation of strain NR mainly depended on influent COD concentrations, which was consistent with the model results.},
}
@article {pmid30059945,
year = {2018},
author = {Wang, HJ and Dai, K and Wang, YQ and Wang, HF and Zhang, F and Zeng, RJ},
title = {Mixed culture fermentation of synthesis gas in the microfiltration and ultrafiltration hollow-fiber membrane biofilm reactors.},
journal = {Bioresource technology},
volume = {267},
number = {},
pages = {650-656},
doi = {10.1016/j.biortech.2018.07.098},
pmid = {30059945},
issn = {1873-2976},
abstract = {The effects of pore sizes on the in-situ utilization of synthesis gas (syngas, H2 and CO) mixed culture fermentation (MCF) in the hollow-fiber membrane biofilm reactor (HfMBR) are not clear. Thus, the ultrafiltration (R1) and microfiltration (R2) HfMBRs were constructed. Syngas was totally consumed within the formed biofilm in R1; contrarily, it accumulated notably in R2. In the batch mode of R1 and R2, volatile fatty acids (VFAs) of acetate, butyrate and caproate were the main metabolites, but the production rate of total VFA in R1 (61.9 mmol-C/(L·d)) was higher than that of R2 (27.6 mmol-C/(L·d)). In the continuous mode, the R1 performance was much better than that of R2, and the biofilm in R2 was even washed out. Furthermore, Clostridium (30.0%) was the main genus in the enriched biofilm of R1, which converted syngas to VFAs. Thus, the ultrafiltration membrane shall be the suitable candidate for syngas MCF.},
}
@article {pmid30059921,
year = {2018},
author = {Jiang, Y and Khan, A and Huang, H and Tian, Y and Yu, X and Xu, Q and Mou, L and Lv, J and Zhang, P and Liu, P and Deng, L and Li, X},
title = {Using nano-attapulgite clay compounded hydrophilic urethane foams (AT/HUFs) as biofilm support enhances oil-refinery wastewater treatment in a biofilm membrane bioreactor.},
journal = {The Science of the total environment},
volume = {646},
number = {},
pages = {606-617},
doi = {10.1016/j.scitotenv.2018.07.149},
pmid = {30059921},
issn = {1879-1026},
abstract = {Petroleum refinery wastewater (PRW) treatments based on biofilm membrane bioreactor (BF-MBR) technology is an ideal approach and biofilm supporting material is a critical factor. In this study, BF-MBR with nano-attapulgite clay compounded hydrophilic urethane foams (AT/HUFs) as a biofilm support was used to treat PRW with a hydraulic retention time of 5 h. The removal rate of 500 mg/L chemical oxygen demand (COD), 15 mg/L NH4+ and 180 NTU of turbidity were 99.73%, 97.48% and 99.99%, which were 23%, 20%, and 6% higher than in the control bioreactor, respectively. These results were comparatively higher than that observed for the sequencing batch reactor (SBR). The death rate of the Spirodela polyrrhiza (L.) irrigated with BF-MBR-treated water was 4.44%, which was similar to that of the plants irrigated with tap water (3.33%) and SBR-treated water (5.56%), but significantly lower than that irrigated with raw water (84.44%). The counts demonstrated by qPCR for total bacteria, denitrifiers, nitrite oxidizing bacteria, ammonia oxidizing bacteria, and ammonia-oxidizing archaea were also higher in BF-MBR than those obtained by SBR. Moreover, the results of 16 s rRNA sequencing have demonstrated that the wastewater remediation microbes were enriched in AT/HUFs, e.g., Acidovorax can degrade polycyclic aromatic hydrocarbons, and Sulfuritalea is an efficient nitrite degrader. In summary, BF-MBR using AT/HUF as a biofilm support improves microbiome of the actived sludge and is reliable for oil-refinery wastewater treatment.},
}
@article {pmid30058521,
year = {2018},
author = {Hussain, M and Fisher, E and Fishman, J},
title = {Bacterial biofilm and chronic sialadenitis, survival outcomes in human papilloma virus positive oral cancer, and long-term use of trimethoprim/sulfamethoxazole in recalcitrant chronic rhinosinusitis.},
journal = {The Journal of laryngology and otology},
volume = {132},
number = {7},
pages = {567},
doi = {10.1017/S0022215118001238},
pmid = {30058521},
issn = {1748-5460},
}
@article {pmid30057443,
year = {2018},
author = {Algburi, A and Zehm, S and Netrebov, V and Weeks, R and Zubovskiy, K and Chikindas, ML},
title = {Benzoyl Peroxide Inhibits Quorum Sensing and Biofilm Formation by Gardnerella vaginalis 14018.},
journal = {Infectious diseases in obstetrics and gynecology},
volume = {2018},
number = {},
pages = {1426109},
doi = {10.1155/2018/1426109},
pmid = {30057443},
issn = {1098-0997},
abstract = {Infection recurrence and antibiotic resistance of bacterial vaginosis-associated pathogenic biofilms underline the need for novel and effective treatment strategies. In this study, we evaluated the antimicrobial, antibiofilm, and quorum sensing inhibitory effects of benzoyl peroxide and salicylic acid against Gardnerella vaginalis ATCC 14018, the predominant pathogen of bacterial vaginosis. While the highest tested concentrations of 250 and 125 μg/mL for both compounds were not sufficient in completely inhibiting the growth of G. vaginalis ATCC 14018, they did prevent biofilm formation by inhibiting the bacterial quorum sensing system in the pathogen. To our knowledge, this report is the first evidence that benzoyl peroxide can have a quorum sensing-mediated biofilm controlling effect, as demonstrated using subinhibitory concentrations of this compound in order to reduce the cost, dosage, and negative side effects associated with current antimicrobial treatments.},
}
@article {pmid30057356,
year = {2018},
author = {Paraje, MG},
title = {[Persist and triumph: persistent cells in microbial biofilm].},
journal = {Revista Argentina de microbiologia},
volume = {50},
number = {3},
pages = {231-233},
doi = {10.1016/j.ram.2018.07.001},
pmid = {30057356},
issn = {0325-7541},
}
@article {pmid30057355,
year = {2018},
author = {Mohammed, YHE and Manukumar, HM and Rakesh, KP and Karthik, CS and Mallu, P and Qin, HL},
title = {Vision for medicine: Staphylococcus aureus biofilm war and unlocking key's for anti-biofilm drug development.},
journal = {Microbial pathogenesis},
volume = {123},
number = {},
pages = {339-347},
doi = {10.1016/j.micpath.2018.07.002},
pmid = {30057355},
issn = {1096-1208},
abstract = {The Staphylococcus aureus biofilm-associated burden is challenging to the field of medicine to eradicate or avoid it. Even though a number of S. aureus biofilm mechanisms understood and established the possible ways of biofilm formation but, still need to know more and require a development of new therapeutic strategies. In this viewpoint, we discuss the underlining biofilm mechanism, its existing systems as active therapeutic agents and as vehicles to transport drugs to the site of infection. The step-back in drug development is due to the emergence of antibiotic-resistant S. aureus. The understanding of bacteria/biofilms is an aspect that we likewise summarize for possible drug development for future as medicine against resistant S. aureus was viewed.},
}
@article {pmid30054101,
year = {2018},
author = {Chen, L and Li, X and Zhou, X and Zeng, J and Ren, Z and Lei, L and Kang, D and Zhang, K and Zou, J and Li, Y},
title = {Inhibition of Enterococcus faecalis Growth and Biofilm Formation by Molecule Targeting Cyclic di-AMP Synthetase Activity.},
journal = {Journal of endodontics},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.joen.2018.05.008},
pmid = {30054101},
issn = {1878-3554},
abstract = {INTRODUCTION: Enterococcus faecalis is correlated with oral diseases including recurrent root canal treatment failure because of its biofilm formation ability and various virulence factors. Cyclic di-AMP (c-di-AMP) is an omnipresent second messenger involved in many crucial cellular physiological processes, including biofilm formation. ST056083 is a small molecule working as an inhibitor of the c-di-AMP synthetase DNA integrity scanning protein (DisA) in vitro. In this study, the impact of ST056083 on E. faecalis DisA activity, bacterial growth, and biofilm formation was tested.<br><br>METHODS: The binding affinity between the protein and ligand was evaluated using the Amber score, and the binding mode was analyzed and visualized using UCSF Chimera (Resource for Biocomputing, Visualization, and Informatics, University of California, San Francisco, San Francisco, CA). The effect of ST056083 on E. faecalis DisA was evaluated using the coralyne assay. The effect of ST056083 on E. faecalis biofilm formation was determined by the biofilm quantification assay, scanning electron microscopic examination, and 3-dimensional confocal laser scanning microscopic assay. The effect of ST056083 on E. faecalis exopolysaccharide synthesis was measured by the anthrone-sulfuric method.<br><br>RESULTS: We expressed and purified E. faecalis DisA in vitro and confirmed the inhibitory effect of ST056083 on its biological activity. In addition, we showed the inhibitory effect of ST056083 on E. faecalis growth, biofilm formation, and exopolysaccharide synthesis.<br><br>CONCLUSIONS: Our findings enhance the understanding of the physiological role of c-di-AMP in E. faecalis and represent a preliminary study on the ST056083 inhibitory effect and mechanism.},
}
@article {pmid30053750,
year = {2018},
author = {Ranieri, MR and Whitchurch, CB and Burrows, LL},
title = {Mechanisms of biofilm stimulation by subinhibitory concentrations of antimicrobials.},
journal = {Current opinion in microbiology},
volume = {45},
number = {},
pages = {164-169},
doi = {10.1016/j.mib.2018.07.006},
pmid = {30053750},
issn = {1879-0364},
abstract = {Biofilms are a typical mode of growth for most microorganisms and provide them with a variety of survival benefits. Biofilms can pose medical and industrial challenges due to their increased tolerance of antimicrobials and disinfectants. Exposure of bacteria to subinhibitory concentrations of those compounds can further exacerbate the problem, as they provoke physiological changes that lead to increased biofilm production and potential therapeutic failure. The protected niche of a biofilm provides conditions that promote selection for persisters and resistant mutants. In this review we discuss our current understanding of the mechanisms underlying biofilm stimulation in response to subinhibitory antimicrobials, and how we might exploit this 'anti-antibiotic' phenotype to treat biofilm-related infections and discover new compounds.},
}
@article {pmid30052962,
year = {2017},
author = {Trøstrup, H and Lerche, CJ and Christophersen, LJ and Thomsen, K and Jensen, PØ and Hougen, HP and Høiby, N and Moser, C},
title = {Erratum: Chronic Pseudomonas aeruginosa biofilm infection impairs murine S100A8/A9 and neutrophil effector cytokines-implications for delayed wound closure?.},
journal = {Pathogens and disease},
volume = {75},
number = {8},
pages = {},
doi = {10.1093/femspd/ftx110},
pmid = {30052962},
issn = {2049-632X},
}
@article {pmid30052909,
year = {2018},
author = {Kakade, P and Mahadik, K and Balaji, KN and Sanyal, K and Nagaraja, V},
title = {Two negative regulators of biofilm development exhibit functional divergence in conferring virulence potential to Candida albicans.},
journal = {FEMS yeast research},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsyr/foy078},
pmid = {30052909},
issn = {1567-1364},
abstract = {Candida albicans, a human pathogen, carries an expanded family of Zn(II)2Cys6 transcription factors. A CTG clade-specific protein Zcf32 and its closely related protein Upc2, a well-conserved transcription factor across the various fungal species, belong to this family of proteins. Unlike Upc2, Zcf32 is poorly studied in C. albicans. Here, we examined roles played by these two related transcription factors in biofilm development and virulence of C. albicans. Our data show that the null mutants of each of Zcf32 or Upc2 form better biofilms than the wild-type suggesting that both of them negatively regulate the biofilm development. While acting as negative regulators of biofilm formation, these two transcription factors target a different set of biofilm genes. A mouse model of candidiasis reveals that zcf32/zcf32 was hypervirulent while upc2/upc2 shows compromised virulence compared to the wild-type. Notably, the absence of Zcf32 enhances detrimental inflammation brought about by TNFα, IFNβ, and IFNγ. upc2/upc2 failed to generate a similar feedback, instead demonstrated an elevated anti-inflammatory (IL4 and IL10) host response. Taking together, we show how a recently evolved transcription factor Zcf32 retained functional resemblance with a more ubiquitous member Upc2 but also functionally diverged from the latter in the regulation of biofilm development and virulence of the pathogen.},
}
@article {pmid30052177,
year = {2018},
author = {Nandu, TG and Subramenium, GA and Shiburaj, S and Viszwapriya, D and Iyer, PM and Balamurugan, K and Rameshkumar, KB and Karutha Pandian, S},
title = {Fukugiside, a biflavonoid from Garcinia travancorica inhibits biofilm formation of Streptococcus pyogenes and its associated virulence factors.},
journal = {Journal of medical microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1099/jmm.0.000799},
pmid = {30052177},
issn = {1473-5644},
abstract = {PURPOSE: Streptococcus pyogenes, a notorious human pathogen thatis responsible for various invasive and non-invasive diseases, possesses multiple virulence armaments, including biofilm formation. The current study demonstrates the anti-biofilm and anti-virulence potential of fukugiside, a biflavonoid isolated from Garciniatravancorica, against S. pyogenes.<br><br>METHODOLOGY: The anti-biofilm activity of fukugiside was assessed and established using microdilution and microscopic analysis. Biochemical assays were performed to assess the effects of fukugiside on important virulence factors, which were further validated using quantitative real-time PCR and in vivo analysis in Caenorhabditis elegans.<br><br>RESULTS: Fukugiside exhibited concentration-dependent biofilm inhibition (79 to 96 %) against multiple M serotypes of S. pyogenes (M1, M56, M65, M74, M100 and st38) with a minimum biofilm inhibitory concentration of 80 µg ml-1. Electron microscopy and biochemical assay revealed a significant reduction in extracellular polymeric substance production. The results for the microbial adhesion to hydrocarbon assay, extracellular protease quantification and differential regulation of the dltA, speB, srv and ropB genes suggested that fukugiside probably inhibits biofilm formation by lowering cell surface hydrophobicity and destabilizing the biofilm matrix. The enhanced susceptibility to phagocytosis evidenced in the blood survival assay goes in unison with the downregulation of mga. The downregulation of important virulence factor-encoding genes such as hasA, slo and col370 suggested impaired virulence. In vivo analysis in C. elegans evinced the non-toxic nature of fukugiside and its anti-virulence potential against S. pyogenes.<br><br>CONCLUSION: Fukugiside exhibits potent anti-biofilm and anti-virulence activity against different M serotypes of S. pyogenes. It is also non-toxic, which augurs well for its clinical application.},
}
@article {pmid30050506,
year = {2018},
author = {Balasubramanian, S and Skaf, J and Holzgrabe, U and Bharti, R and Förstner, KU and Ziebuhr, W and Humeida, UH and Abdelmohsen, UR and Oelschlaeger, TA},
title = {A New Bioactive Compound From the Marine Sponge-Derived Streptomyces sp. SBT348 Inhibits Staphylococcal Growth and Biofilm Formation.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1473},
doi = {10.3389/fmicb.2018.01473},
pmid = {30050506},
issn = {1664-302X},
abstract = {Staphylococcus epidermidis, the common inhabitant of human skin and mucosal surfaces has emerged as an important pathogen in patients carrying surgical implants and medical devices. Entering the body via surgical sites and colonizing the medical devices through formation of multi-layered biofilms leads to refractory and persistent device-related infections (DRIs). Staphylococci organized in biofilms are more tolerant to antibiotics and immune responses, and thus are difficult-to-treat. The consequent morbidity and mortality, and economic losses in health care systems has strongly necessitated the need for development of new anti-bacterial and anti-biofilm-based therapeutics. In this study, we describe the biological activity of a marine sponge-derived Streptomyces sp. SBT348 extract in restraining staphylococcal growth and biofilm formation on polystyrene, glass, medically relevant titan metal, and silicone surfaces. A bioassay-guided fractionation was performed to isolate the active compound (SKC3) from the crude SBT348 extract. Our results demonstrated that SKC3 effectively inhibits the growth (MIC: 31.25 μg/ml) and biofilm formation (sub-MIC range: 1.95-<31.25 μg/ml) of S. epidermidis RP62A in vitro. Chemical characterization of SKC3 by heat and enzyme treatments, and mass spectrometry (HRMS) revealed its heat-stable and non-proteinaceous nature, and high molecular weight (1258.3 Da). Cytotoxicity profiling of SKC3 in vitro on mouse fibroblast (NIH/3T3) and macrophage (J774.1) cell lines, and in vivo on the greater wax moth larvae Galleria mellonella revealed its non-toxic nature at the effective dose. Transcriptome analysis of SKC3 treated S. epidermidis RP62A has further unmasked its negative effect on central metabolism such as carbon flux as well as, amino acid, lipid, and energy metabolism. Taken together, these findings suggest a potential of SKC3 as a putative drug to prevent staphylococcal DRIs.},
}
@article {pmid30049528,
year = {2018},
author = {Fang, Y and Deng, C and Chen, J and Lü, J and Chen, S and Zhou, S},
title = {Accelerating the start-up of the cathodic biofilm by adding acyl-homoserine lactone signaling molecules.},
journal = {Bioresource technology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.biortech.2018.07.095},
pmid = {30049528},
issn = {1873-2976},
abstract = {Electroactive biofilms (EABs) are essential for bioelectrochemical systems, however, the formation of cathodic EABs is more time-consuming than anodic EABs. This study aims to evaluate whether acyl-homoserine lactones (AHLs) could facilitate the start-up of cathodic Geobacter soli EABs. With AHL addition, the biomass, cell viability, and extracellular polymeric substance (EPS) abundance of cathode-associated G. soli EABs were increased. Likewise, redox activities of EPS and outermost proteins in the cathodic EABs were enhanced in the presence of AHLs, which consequently led to better start-up performance of biofilms. Compared to the control without AHLs, start-up lag periods were reduced by approximately 50%, electron uptakes were enhanced by 1.3-2.0 times, and denitrification rates were more than doubled with AHL addition in the start-up cycle, which were comparable to those of mature G. soli cathodic EABs. These findings open up an opportunity for accelerating the start-up of cathodic biofilms via AHLs.},
}
@article {pmid30049271,
year = {2018},
author = {Akens, MK and Chien, C and Katchky, RN and Kreder, HJ and Finkelstein, J and Whyne, CM},
title = {The impact of thermal cycling on Staphylococcus aureus biofilm growth on stainless steel and titanium orthopaedic plates.},
journal = {BMC musculoskeletal disorders},
volume = {19},
number = {1},
pages = {260},
doi = {10.1186/s12891-018-2199-z},
pmid = {30049271},
issn = {1471-2474},
support = {23350//Ontario Centres of Excellence/ ; },
abstract = {BACKGROUND: Orthopaedic implant infections are difficult to eradicate because bacteria adhering to implant surfaces inhibit the ability of the immune system and antibiotics to combat these infections. Thermal cycling is a temperature modulation process that improves performance and longevity of materials through molecular structural reorientation, thereby increasing surface uniformity. Thermal cycling may change material surface properties that reduce the ability for bacteria to adhere to the surface of orthopaedic implants. This study aims to determine whether thermal cycling of orthopaedic implants can reduce bacterial growth.<br><br>METHODS: In a randomized, blinded in-vitro study, titanium and stainless steel plates treated with thermal cycling were compared to controls. Twenty-seven treated and twenty-seven untreated plates were covered with 10 ml tryptic soy broth containing ~ 105 colony forming units (CFU)/ml of bioluminescent Staphylococcus aureus (S. aureus)Xen29 and incubated at 37 °C for 14d. Quantity and viability of bacteria were characterized using bioluminescence imaging, live/dead staining and determination of CFUs.<br><br>RESULTS: Significantly fewer CFUs grow on treated stainless steel plates compared to controls (p = 0.0088). Similar findings were seen in titanium plates (p = 0.0048) following removal of an outlier. No differences were evident in live/dead staining using confocal microscopy, or in metabolic activity determined using bioluminescence imaging (stainless steel plates: p = 0.70; titanium plates: p = 0.26).<br><br>CONCLUSION: This study shows a reduction in CFUs formation on thermal cycled plates in-vitro. Further in-vivo studies are necessary to investigate the influence of thermal cycling on bacterial adhesion during bone healing. Thermal cycling has demonstrated improved wear and strength, with reductions in fatigue and load to failure. The added ability to reduce bacterial adhesions demonstrates another potential benefit of thermal cycling in orthopaedics, representing an opportunity to reduce complications following fracture fixation or arthroplasty.},
}
@article {pmid30048488, year = {2018}, author = {Hussain, MS and Kwon, M and Oh, DH}, title = {Impact of manganese and heme on biofilm formation of Bacillus cereus food isolates.}, journal = {PloS one}, volume = {13}, number = {7}, pages = {e0200958}, doi = {10.1371/journal.pone.0200958}, pmid = {30048488}, issn = {1932-6203}, abstract = {The objective of this study was to determine the impact of manganese (Mn2+) and heme on the biofilm formation characteristics of six B. cereus food isolates and two reference strains (ATCC 10987 and ATCC 14579). The data obtained from the crystal violet assay revealed that addition of a combination of Mn2+ and heme to BHI growth medium induced B. cereus biofilm formation. However, the induction of biofilm formation was strictly strain-dependent. In all of the induced strains, the impact of Mn2+ was greater than that of heme. The impact of these two molecules on the phenotypic characteristics related to biofilm formation, such as cell density, sporulation and swarming ability, was determined in a selected food isolate (GIHE 72-5). Addition of Mn2+ and heme to BHI significantly (p < 0.05) increased the number of cells, which was correlated with the results of crystal violet assays as well as scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) analyses. In addition, induced biofilms showed higher numbers of spores and greater resistance to benzalkonium chloride. The swarming ability of B. cereus planktonic cells was increased in the presence of Mn2+ and heme in BHI. The expression levels of a number of selected genes, which are involved in mobility and extracellular polymeric substances (EPS) formation in B. cereus, were positively correlated with biofilm formation in the presence of Mn2+ and heme in BHI. These results further confirming the role of these molecules in swarming mobility and making matrix components related to B. cereus biofilm formation. These data indicate that signaling molecules present in the food environment might substantially trigger B. cereus biofilm formation, which could pose a threat to the food industry.}, }
@article {pmid30048376, year = {2018}, author = {Kim, YS}, title = {Do Bacteria and Biofilm Play a Role in Double-Capsule Formation around Macrotextured Implants?.}, journal = {Plastic and reconstructive surgery}, volume = {}, number = {}, pages = {}, doi = {10.1097/PRS.0000000000004744}, pmid = {30048376}, issn = {1529-4242}, }
@article {pmid30048200, year = {2018}, author = {Kenaley, KM and Blackson, T and Boylan, L and Ciarlo, J and Antunes, M and Shaffer, TH and Locke, R}, title = {Impact of endotracheal tube biofilm and respiratory secretions on airway resistance and mechanics of breathing in a neonatal lung model.}, journal = {Journal of applied physiology (Bethesda, Md. : 1985)}, volume = {}, number = {}, pages = {}, doi = {10.1152/japplphysiol.00083.2018}, pmid = {30048200}, issn = {1522-1601}, abstract = {Endotracheal tube (ETT) obstruction from biofilm formation is a theoretical risk for intubated preterm neonates. The objective of this study is to determine the impact of ETT biofilm on ETT resistance and minute ventilation in a neonatal respiratory model. Post-extubation 2.5 and 3.0mm ETTs from ventilated preterm infants were matched with unused control ETTs. The pressure gradient across the ETT was measured at set flow rates and converted to airway resistance. Spontaneous breathing tests (SBT) were performed using a virtual patient model and were considered &quot;passed&quot; if minute ventilation of patient ETTs was greater than 60% of controls. Twenty-four 2.5mm ETTs and sixteen 3.0mm ETTs were analyzed. In patient and control ETTs, as flow rate increases, the pressure gradient across the ETT also increases in a linear fashion. Resistance to flow in patient ETTs was statistically different from matched control ETTs (p < 0.001), and patient ETTs had 19.9cmH2O/L/sec greater resistance than control ETTs. Spontaneous breathing tests (SBT) were performed in 27 of 40 ETTs. Twenty-six ETTs &quot;passed&quot; a SBT. In one obstructed 3.0mm ETT, SBT measurements were unobtainable. The clinical impact of endotracheal tube biofilm as measured by a SBT appears to be minimal for the majority of patients in our study group. In one out of 27 ETTs, the presence of a biofilm significantly altered resistance to airflow and resulted in a failed SBT. Gas flow rate and ETT size had a greater impact on resistance to airflow and minute ventilation than ETT biofilm in this study sample.}, }
@article {pmid30048150, year = {2018}, author = {Stevens, AH and Childers, D and Fox-Powell, M and Nicholson, N and Jhoti, E and Cockell, CS}, title = {Growth, Viability, and Death of Planktonic and Biofilm Sphingomonas desiccabilis in Simulated Martian Brines.}, journal = {Astrobiology}, volume = {}, number = {}, pages = {}, doi = {10.1089/ast.2018.1840}, pmid = {30048150}, issn = {1557-8070}, abstract = {Aqueous solutions on Mars are theorized to contain very different ion compositions than those on Earth. To determine the effect of such solutions on typical environmental micro-organisms, which could be released from robotic spacecraft or human exploration activity, we investigated the resistance of Sphingomonas desiccabilis to brines that simulate the composition of martian aqueous environments. S. desiccabilis is a desiccation-resistant, biofilm-forming microbe found in desert crusts. The viability of cells in both planktonic and biofilm forms was measured after exposure to simulated martian brines. Planktonic cells showed a loss of viability over the course of several hours in almost all of the seven brines tested. Biofilms conferred greater resistance to all the brines, including those with low water activity and pH, but even cells in biofilms showed a complete loss of viability in <6 h in the harsher brines and in <2 days in the less harsh brines. One brine, however, allowed the microbes to maintain viability over several days, despite having a water activity and pH lower and ionic strength higher than brines that reduced viability over the same timescales, suggesting important ion-specific effects. These data show that biofilm-forming cells have a greater capacity to resist martian aqueous extremes, but that evaporative or deliquescent brines are likely to be destructive to many organisms over relatively short timescales, with implications for the habitability of Mars and for micro-organisms dispersed by robotic or human explorers.}, }
@article {pmid30047246, year = {2018}, author = {Zhao, T and Zhang, Y and Wu, H and Wang, D and Chen, Y and Zhu, MJ and Ma, LZ}, title = {Extracellular aminopeptidase modulates biofilm development of Pseudomonas aeruginosa by affecting matrix exopolysaccharide and bacterial cell death.}, journal = {Environmental microbiology reports}, volume = {}, number = {}, pages = {}, doi = {10.1111/1758-2229.12682}, pmid = {30047246}, issn = {1758-2229}, abstract = {Biofilm bacteria are embedded within a self-secreted extracellular matrix that contains a considerable amount of proteins including many extracellular enzymes. However, little is known about the roles of such enzymes in biofilm development. Here, we studied Pseudomonas aeruginosa aminopeptidase (PaAP, encoded by PA2939 that we named the gene as paaP in this study), a quorum-sensing-regulated enzyme and one of the most abundant extracellular proteins in the biofilm matrix of this opportunistic pathogen and environmental bacterium. We found that deletion of paaP in P. aeruginosa increased initial attachment and biofilm formation at early stages of biofilm development. After 24-h growth, loss of PaAP resulted in substantial cell death and biofilm disruption. Bacterial cell death was independent of biofilm matrix polysaccharide Psl, while biofilm disruption was due to the degradation of Psl matrix by dead-bacteria-released glycosyl hydrolase PslG, thereby leading to biofilm dispersion. PaAP functioned extracellularly and aminopeptidase catalytic activity was essential for its effect on biofilm development. Our data reveal an important role of extracellular aminopeptidase in biofilm development, suggesting PaAP as a therapeutic target for preventing P. aeruginosa infection and combating biofilm-related complications. This article is protected by copyright. All rights reserved.}, }
@article {pmid30046559, year = {2018}, author = {Barilli, E and Bacci, C and StellaVilla, Z and Merialdi, G and D'Incau, M and Brindani, F and Vismarra, A}, title = {Antimicrobial resistance, biofilm synthesis and virulence genes in Salmonella isolated from pigs bred on intensive farms.}, journal = {Italian journal of food safety}, volume = {2}, number = {7}, pages = {7223}, doi = {10.4081/ijfs.2018.7223}, pmid = {30046559}, issn = {2239-7132}, abstract = {Salmonella is the second cause of food-borne infection in humans in the USA and Europe. Pigs represent the second most important reservoir for the pathogen and the consumption of pork meat is a major risk factor for human salmonellosis. Here, we evaluated the virulence patterns of eleven Salmonella isolated from pigs (carcasses and faces) bred in intensive farms in the north of Italy. The two serotypes identified were S. Typhimurium and its monophasic variant 1,4,5,12:i:-. None of the isolates was an ESBL producer, as confirmed also by PCR. However, the presence of a multi-drug resistant pattern was evident, with all the isolates being resistant to at least to five antimicrobial agents belonging to various classes. Moreover, six out of eleven isolates showed important resistance profiles, such as resistance against colistin and ciprofloxacin, with nine to twelve recorded resistances. The isolates were negative for the biofilm synthesis test, while four different virulotypes were characterized. All the isolates showed the presence of invA, hilA, stn, ssrA, sipC. One sample also harbored ssaR and spvC genes. One strain was positive for all the virulence genes tested and was resistant to 12 antimicrobial agents. The present study contributes new data to the surveillance program for antibiotic resistance. Furthermore, the presence of eleven highly virulent isolates poses concern for human health in relation to their diffusion in the environment.}, }
@article {pmid30048488,
year = {2018},
author = {Hussain, MS and Kwon, M and Oh, DH},
title = {Impact of manganese and heme on biofilm formation of Bacillus cereus food isolates.},
journal = {PloS one},
volume = {13},
number = {7},
pages = {e0200958},
doi = {10.1371/journal.pone.0200958},
pmid = {30048488},
issn = {1932-6203},
abstract = {The objective of this study was to determine the impact of manganese (Mn2+) and heme on the biofilm formation characteristics of six B. cereus food isolates and two reference strains (ATCC 10987 and ATCC 14579). The data obtained from the crystal violet assay revealed that addition of a combination of Mn2+ and heme to BHI growth medium induced B. cereus biofilm formation. However, the induction of biofilm formation was strictly strain-dependent. In all of the induced strains, the impact of Mn2+ was greater than that of heme. The impact of these two molecules on the phenotypic characteristics related to biofilm formation, such as cell density, sporulation and swarming ability, was determined in a selected food isolate (GIHE 72-5). Addition of Mn2+ and heme to BHI significantly (p < 0.05) increased the number of cells, which was correlated with the results of crystal violet assays as well as scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) analyses. In addition, induced biofilms showed higher numbers of spores and greater resistance to benzalkonium chloride. The swarming ability of B. cereus planktonic cells was increased in the presence of Mn2+ and heme in BHI. The expression levels of a number of selected genes, which are involved in mobility and extracellular polymeric substances (EPS) formation in B. cereus, were positively correlated with biofilm formation in the presence of Mn2+ and heme in BHI. These results further confirming the role of these molecules in swarming mobility and making matrix components related to B. cereus biofilm formation. These data indicate that signaling molecules present in the food environment might substantially trigger B. cereus biofilm formation, which could pose a threat to the food industry.},
}
@article {pmid30048376,
year = {2018},
author = {Kim, YS},
title = {Do Bacteria and Biofilm Play a Role in Double-Capsule Formation around Macrotextured Implants?.},
journal = {Plastic and reconstructive surgery},
volume = {},
number = {},
pages = {},
doi = {10.1097/PRS.0000000000004744},
pmid = {30048376},
issn = {1529-4242},
}
@article {pmid30048200,
year = {2018},
author = {Kenaley, KM and Blackson, T and Boylan, L and Ciarlo, J and Antunes, M and Shaffer, TH and Locke, R},
title = {Impact of endotracheal tube biofilm and respiratory secretions on airway resistance and mechanics of breathing in a neonatal lung model.},
journal = {Journal of applied physiology (Bethesda, Md. : 1985)},
volume = {},
number = {},
pages = {},
doi = {10.1152/japplphysiol.00083.2018},
pmid = {30048200},
issn = {1522-1601},
abstract = {Endotracheal tube (ETT) obstruction from biofilm formation is a theoretical risk for intubated preterm neonates. The objective of this study is to determine the impact of ETT biofilm on ETT resistance and minute ventilation in a neonatal respiratory model. Post-extubation 2.5 and 3.0mm ETTs from ventilated preterm infants were matched with unused control ETTs. The pressure gradient across the ETT was measured at set flow rates and converted to airway resistance. Spontaneous breathing tests (SBT) were performed using a virtual patient model and were considered &quot;passed&quot; if minute ventilation of patient ETTs was greater than 60% of controls. Twenty-four 2.5mm ETTs and sixteen 3.0mm ETTs were analyzed. In patient and control ETTs, as flow rate increases, the pressure gradient across the ETT also increases in a linear fashion. Resistance to flow in patient ETTs was statistically different from matched control ETTs (p < 0.001), and patient ETTs had 19.9cmH2O/L/sec greater resistance than control ETTs. Spontaneous breathing tests (SBT) were performed in 27 of 40 ETTs. Twenty-six ETTs &quot;passed&quot; a SBT. In one obstructed 3.0mm ETT, SBT measurements were unobtainable. The clinical impact of endotracheal tube biofilm as measured by a SBT appears to be minimal for the majority of patients in our study group. In one out of 27 ETTs, the presence of a biofilm significantly altered resistance to airflow and resulted in a failed SBT. Gas flow rate and ETT size had a greater impact on resistance to airflow and minute ventilation than ETT biofilm in this study sample.},
}
@article {pmid30048150,
year = {2018},
author = {Stevens, AH and Childers, D and Fox-Powell, M and Nicholson, N and Jhoti, E and Cockell, CS},
title = {Growth, Viability, and Death of Planktonic and Biofilm Sphingomonas desiccabilis in Simulated Martian Brines.},
journal = {Astrobiology},
volume = {},
number = {},
pages = {},
doi = {10.1089/ast.2018.1840},
pmid = {30048150},
issn = {1557-8070},
abstract = {Aqueous solutions on Mars are theorized to contain very different ion compositions than those on Earth. To determine the effect of such solutions on typical environmental micro-organisms, which could be released from robotic spacecraft or human exploration activity, we investigated the resistance of Sphingomonas desiccabilis to brines that simulate the composition of martian aqueous environments. S. desiccabilis is a desiccation-resistant, biofilm-forming microbe found in desert crusts. The viability of cells in both planktonic and biofilm forms was measured after exposure to simulated martian brines. Planktonic cells showed a loss of viability over the course of several hours in almost all of the seven brines tested. Biofilms conferred greater resistance to all the brines, including those with low water activity and pH, but even cells in biofilms showed a complete loss of viability in <6 h in the harsher brines and in <2 days in the less harsh brines. One brine, however, allowed the microbes to maintain viability over several days, despite having a water activity and pH lower and ionic strength higher than brines that reduced viability over the same timescales, suggesting important ion-specific effects. These data show that biofilm-forming cells have a greater capacity to resist martian aqueous extremes, but that evaporative or deliquescent brines are likely to be destructive to many organisms over relatively short timescales, with implications for the habitability of Mars and for micro-organisms dispersed by robotic or human explorers.},
}
@article {pmid30047246,
year = {2018},
author = {Zhao, T and Zhang, Y and Wu, H and Wang, D and Chen, Y and Zhu, MJ and Ma, LZ},
title = {Extracellular aminopeptidase modulates biofilm development of Pseudomonas aeruginosa by affecting matrix exopolysaccharide and bacterial cell death.},
journal = {Environmental microbiology reports},
volume = {},
number = {},
pages = {},
doi = {10.1111/1758-2229.12682},
pmid = {30047246},
issn = {1758-2229},
abstract = {Biofilm bacteria are embedded within a self-secreted extracellular matrix that contains a considerable amount of proteins including many extracellular enzymes. However, little is known about the roles of such enzymes in biofilm development. Here, we studied Pseudomonas aeruginosa aminopeptidase (PaAP, encoded by PA2939 that we named the gene as paaP in this study), a quorum-sensing-regulated enzyme and one of the most abundant extracellular proteins in the biofilm matrix of this opportunistic pathogen and environmental bacterium. We found that deletion of paaP in P. aeruginosa increased initial attachment and biofilm formation at early stages of biofilm development. After 24-h growth, loss of PaAP resulted in substantial cell death and biofilm disruption. Bacterial cell death was independent of biofilm matrix polysaccharide Psl, while biofilm disruption was due to the degradation of Psl matrix by dead-bacteria-released glycosyl hydrolase PslG, thereby leading to biofilm dispersion. PaAP functioned extracellularly and aminopeptidase catalytic activity was essential for its effect on biofilm development. Our data reveal an important role of extracellular aminopeptidase in biofilm development, suggesting PaAP as a therapeutic target for preventing P. aeruginosa infection and combating biofilm-related complications. This article is protected by copyright. All rights reserved.},
}
@article {pmid30046559,
year = {2018},
author = {Barilli, E and Bacci, C and StellaVilla, Z and Merialdi, G and D'Incau, M and Brindani, F and Vismarra, A},
title = {Antimicrobial resistance, biofilm synthesis and virulence genes in Salmonella isolated from pigs bred on intensive farms.},
journal = {Italian journal of food safety},
volume = {2},
number = {7},
pages = {7223},
doi = {10.4081/ijfs.2018.7223},
pmid = {30046559},
issn = {2239-7132},
abstract = {Salmonella is the second cause of food-borne infection in humans in the USA and Europe. Pigs represent the second most important reservoir for the pathogen and the consumption of pork meat is a major risk factor for human salmonellosis. Here, we evaluated the virulence patterns of eleven Salmonella isolated from pigs (carcasses and faces) bred in intensive farms in the north of Italy. The two serotypes identified were S. Typhimurium and its monophasic variant 1,4,5,12:i:-. None of the isolates was an ESBL producer, as confirmed also by PCR. However, the presence of a multi-drug resistant pattern was evident, with all the isolates being resistant to at least to five antimicrobial agents belonging to various classes. Moreover, six out of eleven isolates showed important resistance profiles, such as resistance against colistin and ciprofloxacin, with nine to twelve recorded resistances. The isolates were negative for the biofilm synthesis test, while four different virulotypes were characterized. All the isolates showed the presence of invA, hilA, stn, ssrA, sipC. One sample also harbored ssaR and spvC genes. One strain was positive for all the virulence genes tested and was resistant to 12 antimicrobial agents. The present study contributes new data to the surveillance program for antibiotic resistance. Furthermore, the presence of eleven highly virulent isolates poses concern for human health in relation to their diffusion in the environment.},
}
@article {pmid30043322, year = {2018}, author = {Jaśkiewicz, M and Neubauer, D and Kazor, K and Bartoszewska, S and Kamysz, W}, title = {Antimicrobial Activity of Selected Antimicrobial Peptides Against Planktonic Culture and Biofilm of Acinetobacter baumannii.}, journal = {Probiotics and antimicrobial proteins}, volume = {}, number = {}, pages = {}, doi = {10.1007/s12602-018-9444-5}, pmid = {30043322}, issn = {1867-1314}, support = {ST-02-0087/07/508//Medical University of Gdansk statutory grant/ ; 01-0305/08/508//Polish Ministry of Science and Higher Education Grant for Young Investigators/ ; }, abstract = {Acinetobacter baumannii is one of the most challenging pathogens, on account of its predisposition to develop resistance leading to severe, difficult-to-treat infections. As these bacteria are more usually isolated from nosocomial infections, the new therapeutic options are demanded. Antimicrobial peptides (AMPs) are compounds likely to find application in the treatment of A. baumannii. These compounds exhibit a wide spectrum of antimicrobial activity and were found to be effective against biofilm. In this study, eight AMPs, namely aurein 1.2, CAMEL, citropin 1.1., LL-37, omiganan, r-omiganan, pexiganan, and temporin A, were tested for their antimicrobial activity. A reference strain of A. baumannii ATCC 19606 was used. Antimicrobial assays included determination of the minimum inhibitory concentration and the minimum biofilm eradication concentration. Considering the fact that the majority of A. baumannii infections are associated with mechanical ventilation and the use of indwelling devices, the activity against biofilm was assessed on both a polystyrene surface and tracheal tube fragments. In addition, cytotoxicity (HaCaT) was determined and in vitro selectivity index was calculated.}, }
@article {pmid30043188, year = {2018}, author = {Han, X and Zhang, LJ and Wu, HY and Wu, YF and Zhao, SN}, title = {Investigation of microorganisms involved in kefir biofilm formation.}, journal = {Antonie van Leeuwenhoek}, volume = {}, number = {}, pages = {}, doi = {10.1007/s10482-018-1125-6}, pmid = {30043188}, issn = {1572-9699}, support = {31271906/C200204//National Natural Science Foundation of China/ ; }, abstract = {Kefir is a natural fermentation agent composed of various microorganisms. To address the mechanism of kefir grain formation, we investigated the microbial role in forming kefir biofilms. The results showed that a biofilm could be formed in kefir-fermented milk and the biofilm forming ability reached the maximum at 13 days. The strains Kluyveromyces marxianus, Lactococcus lactis, Leuconostoc mesenteroides, Lactobacillus kefiri, Lactobacillus sunkii and Acetobacter orientalis were isolated from kefir biofilms by the streak-plate method. These microorganisms were analysed with respect to biofilm forming properties, including their surface characterisation (hydrophobicity and zeta potentials) and the microbial aggregation. The results indicated that Klu. marxianus possessed the strongest biofilm forming properties with the strongest hydrophobicity, lowest zeta potential and greatest auto-aggregation ability. When Klu. marxianus and Ac. orientalis were co-cultured with kefir LAB strains respectively, it was found that mixing Klu. marxianus with Lb. sunkii produced the highest co-aggregation ability. These results elucidated the mechanism of kefir biofilm formation and the microorganisms involved.}, }
@article {pmid30042929, year = {2018}, author = {Romo, JA and Pierce, CG and Esqueda, M and Hung, CY and Saville, SP and Lopez-Ribot, JL}, title = {In Vitro Characterization of a Biaryl Amide Anti-virulence Compound Targeting Candida albicans Filamentation and Biofilm Formation.}, journal = {Frontiers in cellular and infection microbiology}, volume = {8}, number = {}, pages = {227}, doi = {10.3389/fcimb.2018.00227}, pmid = {30042929}, issn = {2235-2988}, abstract = {We have previously identified a small molecule compound, N-[3-(allyloxy)-phenyl]-4-methoxybenzamide (9029936), that exerts potent inhibitory activity against filamentation and biofilm formation by the Candida albicans SC5314 strain and represents a lead candidate for the development of anti-virulence approaches against C. albicans infections. Here we present data from a series of experiments to further characterize its in vitro activity and drug-like characteristics. We demonstrate the activity of this compound against a panel of C. albicans clinical isolates, including several displaying resistance to current antifungals; as well as against a set of C. albicans gain of function strains in key transcriptional regulators of antifungal drug resistance. The compound also inhibits filamentation and biofilm formation in the closely related species C. dubliniensis, but not C. glabrata or C. tropicalis. Combinatorial studies reveal the potential of compound 9029936 to be used together with currently available conventional antifungals. Results of serial passage experiments indicate that repeated exposure to this compound does not elicit resistance. Viability staining of C. albicans in the presence of high concentrations of compound 9029936 confirms that the compound is not toxic to fungal cells, and cytological staining using image flow cytometry analysis reveals that treatment with the lead compound affects hyphal length, with additional effects on cell wall and integrity of the membrane system. In vitro pharmacological profiling provides further evidence that the lead compound displays a safe profile, underscoring its excellent &quot;drug-like&quot; characteristics. Altogether these results confirm the potential of this compound to be further developed as a true anti-virulence agent for the treatment of C. albicans infections, including those refractory to treatment with conventional antifungal agents.}, }
@article {pmid30042743, year = {2018}, author = {Zheng, Y and Li, Y and Long, H and Zhao, X and Jia, K and Li, J and Wang, L and Wang, R and Lu, X and Zhang, D}, title = {bifA Regulates Biofilm Development of Pseudomonas putida MnB1 as a Primary Response to H2O2 and Mn2.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1490}, doi = {10.3389/fmicb.2018.01490}, pmid = {30042743}, issn = {1664-302X}, abstract = {Pseudomonas putida (P. putida) MnB1 is a widely used model strain in environment science and technology for determining microbial manganese oxidation. Numerous studies have demonstrated that the growth and metabolism of P. putida MnB1 are influenced by various environmental factors. In this study, we investigated the effects of hydrogen peroxide (H2O2) and manganese (Mn2+) on proliferation, Mn2+ acquisition, anti-oxidative system, and biofilm formation of P. putida MnB1. The related orthologs of 4 genes, mco, mntABC, sod, and bifA, were amplified from P. putida GB1 and their involvement were assayed, respectively. We found that P. putida MnB1 degraded H2O2, and quickly recovered for proliferation, but its intracellular oxidative stress state was maintained, with rapid biofilm formation after H2O2 depletion. The data from mco, mntABC, sod and bifA expression levels by qRT-PCR, elucidated a sensitivity toward bifA-mediated biofilm formation, in contrary to intracellular anti-oxidative system under H2O2 exposure. Meanwhile, Mn2+ ion supply inhibited biofilm formation of P. putida MnB1. The expression pattern of these genes showed that Mn2+ ion supply likely functioned to modulate biofilm formation rather than only acting as nutrient substrate for P. putida MnB1. Furthermore, blockade of BifA activity by GTP increased the formation and development of biofilms during H2O2 exposure, while converse response to Mn2+ ion supply was evident. These distinct cellular responses to H2O2 and Mn2+ provide insights on the common mechanism by which environmental microorganisms may be protected from exogenous factors. We postulate that BifA-mediated biofilm formation but not intracellular anti-oxidative system may be a primary protective strategy adopted by P. putida MnB1. These findings will highlight the understanding of microbial adaptation mechanisms to distinct environmental stresses.}, }
@article {pmid30042739, year = {2018}, author = {Khandekar, S and Liebens, V and Fauvart, M and Tulkens, PM and Michiels, J and Van Bambeke, F}, title = {The Putative De-N-acetylase DnpA Contributes to Intracellular and Biofilm-Associated Persistence of Pseudomonas aeruginosa Exposed to Fluoroquinolones.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1455}, doi = {10.3389/fmicb.2018.01455}, pmid = {30042739}, issn = {1664-302X}, abstract = {Persisters are the fraction of antibiotic-exposed bacteria transiently refractory to killing and are recognized as a cause of antibiotic treatment failure. The putative de-N-acetylase DnpA increases persister levels in Pseudomonas aeruginosa upon exposure to fluoroquinolones in broth. In this study the wild-type PAO1 and its dnpA insertion mutant (dnpA::Tn) were used in parallel and compared for their capacity to generate persisters in broth (surviving fraction after exposure to high antibiotic concentrations) and their susceptibility to antibiotics in models of intracellular infection of THP-1 monocytes and of biofilms grown in microtiter plates. Multiplication in monocytes was evaluated by fluorescence dilution of GFP (expressed under the control of an inducible promoter) using flow cytometry. Gene expression was measured by quantitative RT-PCR. When exposed to fluoroquinolones (ciprofloxacin or levofloxacin) but not to meropenem or amikacin, the dnpA::Tn mutant showed a 3- to 10-fold lower persister fraction in broth. In infected monocytes, fluoroquinolones (but not the other antibiotics) were more effective (difference in Emax: 1.5 log cfu) against the dnpA::Tn mutant than against the wild-type PAO1. Dividing intracellular bacteria were more frequently seen (1.5 to 1.9-fold) with the fluoroquinolone-exposed dnpA::Tn mutant than with its parental strain. Fluoroquinolones (but not the other antibiotics) were also 3-fold more potent to prevent biofilm formation by the dnpA::Tn mutant than by PAO1 as well as to act upon biofilms (1-3 days of maturity) formed by the mutant than by the parental strain. Fluoroquinolones induced the expression of gyrA (4.5-7 fold) and mexX (3.6-5.4 fold) in the parental strain but to a lower extent (3-4-fold for gyrA and 1.8-2.8-fold for mexX, respectively) in the dnpA::Tn mutant. Thus, our data show that a dnpA insertion mutant of P. aeruginosa is more receptive to fluoroquinolone antibacterial effects than its parental strain in infected monocytes or in biofilms. The mechanism of this higher responsiveness could involve a reduced overexpression of the fluoroquinolone target.}, }
@article {pmid30042679, year = {2018}, author = {Ding, W and Zhou, Y and Qu, Q and Cui, W and God'spower, BO and Liu, Y and Chen, X and Chen, M and Yang, Y and Li, Y}, title = {Azithromycin Inhibits Biofilm Formation by Staphylococcus xylosus and Affects Histidine Biosynthesis Pathway.}, journal = {Frontiers in pharmacology}, volume = {9}, number = {}, pages = {740}, doi = {10.3389/fphar.2018.00740}, pmid = {30042679}, issn = {1663-9812}, abstract = {Staphylococcus xylosus, a coagulase-negative, non-pathogenic bacterium, responsible for opportunistic infections in humans and bovine mastitis, has the ability to form biofilms, which are responsible for persistent infections and antibiotic resistance. In our study, azithromycin significantly inhibited biofilm formation by altering protein expression. Of the 1764 proteins measured by the isobaric Tag for Relative and Absolute Quantification (iTRAQ) technique, only 148 proteins showed significantly different expression between the azithromycin-treated and untreated cells. Most ribosomal proteins were markedly up-regulated, and the expression of the proteins involved in histidine biosynthesis, which, in turn, influence biofilm formation, was down-regulated, particularly imidazole glycerophosphate dehydratase (IGPD). Previously, we had observed that IGPD plays an important role in biofilm formation by S. xylosus. Therefore, hisB expression was studied by real-time PCR, and the interactions between azithromycin and IGPD were predicted by molecular docking analysis. hisB was found to be significantly down-regulated, and six bond interactions were observed between azithromycin and IGPD. Many active atoms of azithromycin did not interact with the biologically active site of IGPD. Surface plasmon resonance analysis used to further study the relationship between IGPD and azithromycin showed minimum interaction between them. Histidine content in the azithromycin-treated and untreated groups was determined. We noted a slight difference, which was not consistent with the expression of the proteins involved in histidine biosynthesis. Therefore, histidine degradation into glutamate was also studied, and we found that all proteins were down-regulated. This could be the reason why histidine content showed little change between the treated and untreated groups. In summary, we found that azithromycin is a potential inhibitor of S. xylosus biofilm formation, and the underlying mechanism was preliminarily elucidated in this study.}, }
@article {pmid30042337, year = {2018}, author = {Dasagrandhi, C and Park, S and Jung, WK and Kim, YM}, title = {Antibacterial and Biofilm Modulating Potential of Ferulic Acid-Grafted Chitosan against Human Pathogenic Bacteria.}, journal = {International journal of molecular sciences}, volume = {19}, number = {8}, pages = {}, doi = {10.3390/ijms19082157}, pmid = {30042337}, issn = {1422-0067}, abstract = {The emergence of more virulent forms of human pathogenic bacteria with multi-drug resistance is a serious global issue and requires alternative control strategies. The current study focused on investigating the antibacterial and antibiofilm potential of ferulic acid-grafted chitosan (CFA) against Listeria monocytogenes (LM), Pseudomonas aeruginosa (PA), and Staphylococcus aureus (SA). The result showed that CFA at 64 µg/mL concentration exhibits bactericidal action against LM and SA (>4 log reduction) and bacteriostatic action against PA (<2 log colony forming units/mL reduction) within 24 h of incubation. Further studies based on propidium iodide uptake assay, measurement of material released from the cell, and electron microscopic analysis revealed that the bactericidal action of CFA was due to altered membrane integrity and permeability. CFA dose dependently inhibited biofilm formation (52⁻89% range), metabolic activity (30.8⁻75.1% range) and eradicated mature biofilms, and reduced viability (71⁻82% range) of the test bacteria. Also, the swarming motility of LM was differentially affected at sub-minimum inhibitory concentration (MIC) concentrations of CFA. In the present study, the ability of CFA to kill and alter the virulence production in human pathogenic bacteria will offer insights into a new scope for the application of these biomaterials in healthcare to effectively treat bacterial infections.}, }
@article {pmid30041533, year = {2018}, author = {Becirovic, A and Abdi-Dezfuli, JF and Hansen, MF and Lie, SA and Vasstrand, EN and Bolstad, AI}, title = {The effects of a probiotic milk drink on bacterial composition in the supra- and subgingival biofilm: a pilot study.}, journal = {Beneficial microbes}, volume = {}, number = {}, pages = {1-10}, doi = {10.3920/BM2018.0009}, pmid = {30041533}, issn = {1876-2891}, abstract = {Probiotics can convert a dysbiotic bacterial environment into a healthy one. The aim of the present study was to assess the effect of daily intake of a probiotic milk drink on the composition of bacterial species in dental supra- and subgingival biofilms. Sixteen dental students were enrolled into this study with a crossover, within subject, design. The participants were asked to allow plaque accumulation by refraining from cleaning their molars during two separate periods, each lasting three weeks. Each period consisted of an initial professional dental cleaning procedure done at the university clinic, then a 3 week plaque accumulation period, followed by a return to the clinic for supra- and subgingival plaque sampling. The first period served as a control, and during the second plaque accumulation period the participants drank 200 ml probiotic milk beverage each day. The accumulated plaque removed at the end of the accumulation period was later tested against a panel of 20 oral bacterial species using the checkerboard method. Three weeks consumption of a probiotic beverage led to a significant reduction in 15 of 20 bacterial species present in supragingival plaque and a reduction in 4 of 20 bacterial species in subgingival plaque (all P<0.05). This study showed a favorable effect of probiotics on periodontopathic bacteria in dental biofilms. The potential influence of this kind of probiotic in prevention or treatment of periodontal inflammation deserves further study.}, }
@article {pmid30043322,
year = {2018},
author = {Jaśkiewicz, M and Neubauer, D and Kazor, K and Bartoszewska, S and Kamysz, W},
title = {Antimicrobial Activity of Selected Antimicrobial Peptides Against Planktonic Culture and Biofilm of Acinetobacter baumannii.},
journal = {Probiotics and antimicrobial proteins},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12602-018-9444-5},
pmid = {30043322},
issn = {1867-1314},
support = {ST-02-0087/07/508//Medical University of Gdansk statutory grant/ ; 01-0305/08/508//Polish Ministry of Science and Higher Education Grant for Young Investigators/ ; },
abstract = {Acinetobacter baumannii is one of the most challenging pathogens, on account of its predisposition to develop resistance leading to severe, difficult-to-treat infections. As these bacteria are more usually isolated from nosocomial infections, the new therapeutic options are demanded. Antimicrobial peptides (AMPs) are compounds likely to find application in the treatment of A. baumannii. These compounds exhibit a wide spectrum of antimicrobial activity and were found to be effective against biofilm. In this study, eight AMPs, namely aurein 1.2, CAMEL, citropin 1.1., LL-37, omiganan, r-omiganan, pexiganan, and temporin A, were tested for their antimicrobial activity. A reference strain of A. baumannii ATCC 19606 was used. Antimicrobial assays included determination of the minimum inhibitory concentration and the minimum biofilm eradication concentration. Considering the fact that the majority of A. baumannii infections are associated with mechanical ventilation and the use of indwelling devices, the activity against biofilm was assessed on both a polystyrene surface and tracheal tube fragments. In addition, cytotoxicity (HaCaT) was determined and in vitro selectivity index was calculated.},
}
@article {pmid30043188,
year = {2018},
author = {Han, X and Zhang, LJ and Wu, HY and Wu, YF and Zhao, SN},
title = {Investigation of microorganisms involved in kefir biofilm formation.},
journal = {Antonie van Leeuwenhoek},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10482-018-1125-6},
pmid = {30043188},
issn = {1572-9699},
support = {31271906/C200204//National Natural Science Foundation of China/ ; },
abstract = {Kefir is a natural fermentation agent composed of various microorganisms. To address the mechanism of kefir grain formation, we investigated the microbial role in forming kefir biofilms. The results showed that a biofilm could be formed in kefir-fermented milk and the biofilm forming ability reached the maximum at 13 days. The strains Kluyveromyces marxianus, Lactococcus lactis, Leuconostoc mesenteroides, Lactobacillus kefiri, Lactobacillus sunkii and Acetobacter orientalis were isolated from kefir biofilms by the streak-plate method. These microorganisms were analysed with respect to biofilm forming properties, including their surface characterisation (hydrophobicity and zeta potentials) and the microbial aggregation. The results indicated that Klu. marxianus possessed the strongest biofilm forming properties with the strongest hydrophobicity, lowest zeta potential and greatest auto-aggregation ability. When Klu. marxianus and Ac. orientalis were co-cultured with kefir LAB strains respectively, it was found that mixing Klu. marxianus with Lb. sunkii produced the highest co-aggregation ability. These results elucidated the mechanism of kefir biofilm formation and the microorganisms involved.},
}
@article {pmid30042929,
year = {2018},
author = {Romo, JA and Pierce, CG and Esqueda, M and Hung, CY and Saville, SP and Lopez-Ribot, JL},
title = {In Vitro Characterization of a Biaryl Amide Anti-virulence Compound Targeting Candida albicans Filamentation and Biofilm Formation.},
journal = {Frontiers in cellular and infection microbiology},
volume = {8},
number = {},
pages = {227},
doi = {10.3389/fcimb.2018.00227},
pmid = {30042929},
issn = {2235-2988},
abstract = {We have previously identified a small molecule compound, N-[3-(allyloxy)-phenyl]-4-methoxybenzamide (9029936), that exerts potent inhibitory activity against filamentation and biofilm formation by the Candida albicans SC5314 strain and represents a lead candidate for the development of anti-virulence approaches against C. albicans infections. Here we present data from a series of experiments to further characterize its in vitro activity and drug-like characteristics. We demonstrate the activity of this compound against a panel of C. albicans clinical isolates, including several displaying resistance to current antifungals; as well as against a set of C. albicans gain of function strains in key transcriptional regulators of antifungal drug resistance. The compound also inhibits filamentation and biofilm formation in the closely related species C. dubliniensis, but not C. glabrata or C. tropicalis. Combinatorial studies reveal the potential of compound 9029936 to be used together with currently available conventional antifungals. Results of serial passage experiments indicate that repeated exposure to this compound does not elicit resistance. Viability staining of C. albicans in the presence of high concentrations of compound 9029936 confirms that the compound is not toxic to fungal cells, and cytological staining using image flow cytometry analysis reveals that treatment with the lead compound affects hyphal length, with additional effects on cell wall and integrity of the membrane system. In vitro pharmacological profiling provides further evidence that the lead compound displays a safe profile, underscoring its excellent &quot;drug-like&quot; characteristics. Altogether these results confirm the potential of this compound to be further developed as a true anti-virulence agent for the treatment of C. albicans infections, including those refractory to treatment with conventional antifungal agents.},
}
@article {pmid30042743,
year = {2018},
author = {Zheng, Y and Li, Y and Long, H and Zhao, X and Jia, K and Li, J and Wang, L and Wang, R and Lu, X and Zhang, D},
title = {bifA Regulates Biofilm Development of Pseudomonas putida MnB1 as a Primary Response to H2O2 and Mn2.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1490},
doi = {10.3389/fmicb.2018.01490},
pmid = {30042743},
issn = {1664-302X},
abstract = {Pseudomonas putida (P. putida) MnB1 is a widely used model strain in environment science and technology for determining microbial manganese oxidation. Numerous studies have demonstrated that the growth and metabolism of P. putida MnB1 are influenced by various environmental factors. In this study, we investigated the effects of hydrogen peroxide (H2O2) and manganese (Mn2+) on proliferation, Mn2+ acquisition, anti-oxidative system, and biofilm formation of P. putida MnB1. The related orthologs of 4 genes, mco, mntABC, sod, and bifA, were amplified from P. putida GB1 and their involvement were assayed, respectively. We found that P. putida MnB1 degraded H2O2, and quickly recovered for proliferation, but its intracellular oxidative stress state was maintained, with rapid biofilm formation after H2O2 depletion. The data from mco, mntABC, sod and bifA expression levels by qRT-PCR, elucidated a sensitivity toward bifA-mediated biofilm formation, in contrary to intracellular anti-oxidative system under H2O2 exposure. Meanwhile, Mn2+ ion supply inhibited biofilm formation of P. putida MnB1. The expression pattern of these genes showed that Mn2+ ion supply likely functioned to modulate biofilm formation rather than only acting as nutrient substrate for P. putida MnB1. Furthermore, blockade of BifA activity by GTP increased the formation and development of biofilms during H2O2 exposure, while converse response to Mn2+ ion supply was evident. These distinct cellular responses to H2O2 and Mn2+ provide insights on the common mechanism by which environmental microorganisms may be protected from exogenous factors. We postulate that BifA-mediated biofilm formation but not intracellular anti-oxidative system may be a primary protective strategy adopted by P. putida MnB1. These findings will highlight the understanding of microbial adaptation mechanisms to distinct environmental stresses.},
}
@article {pmid30042739,
year = {2018},
author = {Khandekar, S and Liebens, V and Fauvart, M and Tulkens, PM and Michiels, J and Van Bambeke, F},
title = {The Putative De-N-acetylase DnpA Contributes to Intracellular and Biofilm-Associated Persistence of Pseudomonas aeruginosa Exposed to Fluoroquinolones.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1455},
doi = {10.3389/fmicb.2018.01455},
pmid = {30042739},
issn = {1664-302X},
abstract = {Persisters are the fraction of antibiotic-exposed bacteria transiently refractory to killing and are recognized as a cause of antibiotic treatment failure. The putative de-N-acetylase DnpA increases persister levels in Pseudomonas aeruginosa upon exposure to fluoroquinolones in broth. In this study the wild-type PAO1 and its dnpA insertion mutant (dnpA::Tn) were used in parallel and compared for their capacity to generate persisters in broth (surviving fraction after exposure to high antibiotic concentrations) and their susceptibility to antibiotics in models of intracellular infection of THP-1 monocytes and of biofilms grown in microtiter plates. Multiplication in monocytes was evaluated by fluorescence dilution of GFP (expressed under the control of an inducible promoter) using flow cytometry. Gene expression was measured by quantitative RT-PCR. When exposed to fluoroquinolones (ciprofloxacin or levofloxacin) but not to meropenem or amikacin, the dnpA::Tn mutant showed a 3- to 10-fold lower persister fraction in broth. In infected monocytes, fluoroquinolones (but not the other antibiotics) were more effective (difference in Emax: 1.5 log cfu) against the dnpA::Tn mutant than against the wild-type PAO1. Dividing intracellular bacteria were more frequently seen (1.5 to 1.9-fold) with the fluoroquinolone-exposed dnpA::Tn mutant than with its parental strain. Fluoroquinolones (but not the other antibiotics) were also 3-fold more potent to prevent biofilm formation by the dnpA::Tn mutant than by PAO1 as well as to act upon biofilms (1-3 days of maturity) formed by the mutant than by the parental strain. Fluoroquinolones induced the expression of gyrA (4.5-7 fold) and mexX (3.6-5.4 fold) in the parental strain but to a lower extent (3-4-fold for gyrA and 1.8-2.8-fold for mexX, respectively) in the dnpA::Tn mutant. Thus, our data show that a dnpA insertion mutant of P. aeruginosa is more receptive to fluoroquinolone antibacterial effects than its parental strain in infected monocytes or in biofilms. The mechanism of this higher responsiveness could involve a reduced overexpression of the fluoroquinolone target.},
}
@article {pmid30042679,
year = {2018},
author = {Ding, W and Zhou, Y and Qu, Q and Cui, W and God'spower, BO and Liu, Y and Chen, X and Chen, M and Yang, Y and Li, Y},
title = {Azithromycin Inhibits Biofilm Formation by Staphylococcus xylosus and Affects Histidine Biosynthesis Pathway.},
journal = {Frontiers in pharmacology},
volume = {9},
number = {},
pages = {740},
doi = {10.3389/fphar.2018.00740},
pmid = {30042679},
issn = {1663-9812},
abstract = {Staphylococcus xylosus, a coagulase-negative, non-pathogenic bacterium, responsible for opportunistic infections in humans and bovine mastitis, has the ability to form biofilms, which are responsible for persistent infections and antibiotic resistance. In our study, azithromycin significantly inhibited biofilm formation by altering protein expression. Of the 1764 proteins measured by the isobaric Tag for Relative and Absolute Quantification (iTRAQ) technique, only 148 proteins showed significantly different expression between the azithromycin-treated and untreated cells. Most ribosomal proteins were markedly up-regulated, and the expression of the proteins involved in histidine biosynthesis, which, in turn, influence biofilm formation, was down-regulated, particularly imidazole glycerophosphate dehydratase (IGPD). Previously, we had observed that IGPD plays an important role in biofilm formation by S. xylosus. Therefore, hisB expression was studied by real-time PCR, and the interactions between azithromycin and IGPD were predicted by molecular docking analysis. hisB was found to be significantly down-regulated, and six bond interactions were observed between azithromycin and IGPD. Many active atoms of azithromycin did not interact with the biologically active site of IGPD. Surface plasmon resonance analysis used to further study the relationship between IGPD and azithromycin showed minimum interaction between them. Histidine content in the azithromycin-treated and untreated groups was determined. We noted a slight difference, which was not consistent with the expression of the proteins involved in histidine biosynthesis. Therefore, histidine degradation into glutamate was also studied, and we found that all proteins were down-regulated. This could be the reason why histidine content showed little change between the treated and untreated groups. In summary, we found that azithromycin is a potential inhibitor of S. xylosus biofilm formation, and the underlying mechanism was preliminarily elucidated in this study.},
}
@article {pmid30042337,
year = {2018},
author = {Dasagrandhi, C and Park, S and Jung, WK and Kim, YM},
title = {Antibacterial and Biofilm Modulating Potential of Ferulic Acid-Grafted Chitosan against Human Pathogenic Bacteria.},
journal = {International journal of molecular sciences},
volume = {19},
number = {8},
pages = {},
doi = {10.3390/ijms19082157},
pmid = {30042337},
issn = {1422-0067},
abstract = {The emergence of more virulent forms of human pathogenic bacteria with multi-drug resistance is a serious global issue and requires alternative control strategies. The current study focused on investigating the antibacterial and antibiofilm potential of ferulic acid-grafted chitosan (CFA) against Listeria monocytogenes (LM), Pseudomonas aeruginosa (PA), and Staphylococcus aureus (SA). The result showed that CFA at 64 µg/mL concentration exhibits bactericidal action against LM and SA (>4 log reduction) and bacteriostatic action against PA (<2 log colony forming units/mL reduction) within 24 h of incubation. Further studies based on propidium iodide uptake assay, measurement of material released from the cell, and electron microscopic analysis revealed that the bactericidal action of CFA was due to altered membrane integrity and permeability. CFA dose dependently inhibited biofilm formation (52⁻89% range), metabolic activity (30.8⁻75.1% range) and eradicated mature biofilms, and reduced viability (71⁻82% range) of the test bacteria. Also, the swarming motility of LM was differentially affected at sub-minimum inhibitory concentration (MIC) concentrations of CFA. In the present study, the ability of CFA to kill and alter the virulence production in human pathogenic bacteria will offer insights into a new scope for the application of these biomaterials in healthcare to effectively treat bacterial infections.},
}
@article {pmid30041533,
year = {2018},
author = {Becirovic, A and Abdi-Dezfuli, JF and Hansen, MF and Lie, SA and Vasstrand, EN and Bolstad, AI},
title = {The effects of a probiotic milk drink on bacterial composition in the supra- and subgingival biofilm: a pilot study.},
journal = {Beneficial microbes},
volume = {},
number = {},
pages = {1-10},
doi = {10.3920/BM2018.0009},
pmid = {30041533},
issn = {1876-2891},
abstract = {Probiotics can convert a dysbiotic bacterial environment into a healthy one. The aim of the present study was to assess the effect of daily intake of a probiotic milk drink on the composition of bacterial species in dental supra- and subgingival biofilms. Sixteen dental students were enrolled into this study with a crossover, within subject, design. The participants were asked to allow plaque accumulation by refraining from cleaning their molars during two separate periods, each lasting three weeks. Each period consisted of an initial professional dental cleaning procedure done at the university clinic, then a 3 week plaque accumulation period, followed by a return to the clinic for supra- and subgingival plaque sampling. The first period served as a control, and during the second plaque accumulation period the participants drank 200 ml probiotic milk beverage each day. The accumulated plaque removed at the end of the accumulation period was later tested against a panel of 20 oral bacterial species using the checkerboard method. Three weeks consumption of a probiotic beverage led to a significant reduction in 15 of 20 bacterial species present in supragingival plaque and a reduction in 4 of 20 bacterial species in subgingival plaque (all P<0.05). This study showed a favorable effect of probiotics on periodontopathic bacteria in dental biofilms. The potential influence of this kind of probiotic in prevention or treatment of periodontal inflammation deserves further study.},
}
@article {pmid30041001,
year = {2018},
author = {Xu, Z and Manukumar, HM and Rakesh, KP and Karthik, CS and Ngendra Prasad, HS and Swamy, N and Mallu, P and Yasser Hunnein, EM and Qin, HL},
title = {Role of BP*C@AgNPs in Bap-dependent multicellular behavior of clinically important methicillin-resistant Staphylococcus aureus (MRSA) biofilm adherence: A key virulence study.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2018.07.025},
pmid = {30041001},
issn = {1096-1208},
abstract = {Bacterial adhesion is a threshold event in the formation of biofilms which leads to serious bacterial diseases. This shows that the underlining the problem is interesting and need to solve the problem of biofilm-related complications. To support this, in the present study, we first time initiated to understand the role of methicillin-resistant Staphylococcus aureus (MRSA) biofilm using previously developed benzodioxane midst piperazine decorated chitosan silver nanoparticles (BP*C@AgNPs). The BP*C@AgNPs studied for antimicrobial, anti-biofilm, biofilm adherence inhibition, the role of ions in biofilm, and an antibiotic cocktail in the treatment of biofilm was assessed. The results showed that, the significant biocidal role of BP*C@AgNPs in controlling the MRSA biofilm and interaction of biofilm protein to calcium ions were significantly decreased. This confirms that calcium ion involved in the biofilm formation and for the treatment of BP*C@AgNPs, cocktail of enzyme and antibiotic have the promising therapeutic value was observed. In future the locking of biofilm protein and its expression in presence of calcium ion was interesting, and greater application related to biofilm infection was warrantable.},
}
@article {pmid30039322,
year = {2018},
author = {Chakraborty, P and Daware, AV and Kumari, M and Chatterjee, A and Bhattacharyya, D and Mitra, G and Akhter, Y and Bhattacharjee, S and Tribedi, P},
title = {Free tryptophan residues inhibit quorum sensing of Pseudomonas aeruginosa: a potential approach to inhibit the development of microbial biofilm.},
journal = {Archives of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00203-018-1557-4},
pmid = {30039322},
issn = {1432-072X},
abstract = {Microbial biofilm reveals a cluster of microbial population aggregated on a surface. Pseudomonas aeruginosa, a strong biofilm forming organism, often causes several human diseases. Microorganism-based diseases become more difficult to manage when the causative organism develops biofilm during the course of disease progression as the organism attains alarming drug resistance in biofilm form. Agents inhibiting microbial biofilm formation could be considered as a potential tool to weaken the extent of microbial pathogenesis. Tryptophan has already been reported as a promising agent against the biofilm development by P. aeruginosa. In the current study, we had focused on the underlying mechanism of microbial biofilm inhibition of P. aeruginosa under the influence of tryptophan. The expression level of the mRNA of the genes (lasR, lasB and lasI) associated with quorum sensing was compared between tryptophan treated and untreated cells under similar conditions using real time polymerase chain reaction (RT-PCR). The results showed that the tested concentrations of tryptophan considerably reduced the expression of those genes (lasR, lasB and lasI) that are required during the occurrence of quorum sensing in P. aeruginosa. Molecular docking also revealed that tryptophan can interact with the proteins responsible for the occurrence of quorum sensing in P. aeruginosa. The cytotoxicity assay was carried out wherein we observed that the tested concentration of tryptophan did not show any considerable cytotoxicity against the RAW 264.7 macrophage cell line. From this study, it may be concluded that the tryptophan-mediated inhibition of biofilm formation is associated with interference of quorum sensing in P. aeruginosa. Hence, tryptophan could be used as a potential agent against the microbial biofilm mediated pathogenesis.},
}
@article {pmid30036851,
year = {2018},
author = {Lu, B and Lu, F and Ran, L and Yu, K and Xiao, Y and Li, Z and Dai, F and Wu, D and Lan, G},
title = {Imidazole-molecule-capped chitosan-gold nanocomposites with enhanced antimicrobial activity for treating biofilm-related infections.},
journal = {Journal of colloid and interface science},
volume = {531},
number = {},
pages = {269-281},
doi = {10.1016/j.jcis.2018.07.058},
pmid = {30036851},
issn = {1095-7103},
abstract = {Biofilms that are widely associated with persistent bacterial infections impose a heavy burden on patients primarily due to their formidable resistance to conventional antiseptic drugs and local immune defense. Here, we successfully synthesized functional gold nanocomposites (CS-Au@MMT) by reducing chloroauric acid in the presence of biocompatible chitosan polymers with cationic amine and the small molecule 2-mercapto-1-methylimidazole (MMT). The cationic amine allowed transport of the CS-Au@MMT to the negatively charged sites at the surface of bacterial cells though electrostatic adhesion, with synergistic effects from the gold nanoparticles and MMT then exerting a strong bactericidal effect to inhibit biofilm formation. For established mature biofilms, CS-Au@MMT was able to adhere to the biofilm surface to render nearby bacterial cells inactive, resulting in biofilm rupture. This allowed CS-Au@MMT to penetrate through the biofilm, leading to sustained damage and achieving biofilm elimination. Furthermore, the nanocomposites efficiently inhibited infections induced by mature biofilm in vivo. These findings indicated that the CS-Au@MMT nanocomposites provide ease of synthesis and fabrication, high bactericidal effect, and low toxicity; thus, they show potential as biofilm-disrupting agents for biomedical and industrial applications.},
}
@article {pmid30036345,
year = {2018},
author = {Wang, C and Luan, J and Xin, M},
title = {Capsular biofilm formation at the interface of textured expanders and human acellular dermal matrix.},
journal = {Plastic and reconstructive surgery},
volume = {},
number = {},
pages = {},
doi = {10.1097/PRS.0000000000004781},
pmid = {30036345},
issn = {1529-4242},
}
@article {pmid30036344,
year = {2018},
author = {Danino, MA and Efanov, JI and Paek, L and Nelea, MI},
title = {Capsular biofilm formation at the interface of textured implants and acellular dermal matrix: A comparative scanning electron microscopy study.},
journal = {Plastic and reconstructive surgery},
volume = {},
number = {},
pages = {},
doi = {10.1097/PRS.0000000000004782},
pmid = {30036344},
issn = {1529-4242},
}
@article {pmid30034907,
year = {2018},
author = {Zhou, X and Meng, J and Yu, Z and Miao, L and Jin, C},
title = {The Alterations of Biofilm Formation and EPS Characteristics of a Diatom by a Sponge-Associated Bacterium Psychrobacter sp.},
journal = {Scientifica},
volume = {2018},
number = {},
pages = {1892520},
doi = {10.1155/2018/1892520},
pmid = {30034907},
issn = {2090-908X},
abstract = {A sponge-associated bacterium, which was identified as Psychrobacter sp. in this study, was found with high activity against biofilm formation of benthic diatoms, including Amphora sp., Nitzschia closterium, Nitzschia frustulum, and Stauroneis sp. The activity against diatom biofilm formation by the tested strain was confirmed mostly in the culture supernatant and could be extracted using organic solvents. Treatment with its supernatant crude extract significantly reduced the cells of Stauroneis sp. forming biofilm and slightly increased the cells floating in the culture medium, which results in the ratio of biofilm cell/floating cell altering from 0.736 in control to 0.414 in treatment. Use of the supernatant crude extract led to increased production of extracellular polymeric substances (EPSs) by diatom Stauroneis sp. from 16.66 to 41.59 (g/g cell dry weight). The increase in EPS production was mainly contributed by soluble EPS (SL-EPS) and followed by the EPS that was tightly bound to biofilm cells (BF-TB-EPS). In addition, the supernatant crude extract caused significant changes in the monosaccharides composition of the EPS of Stauroneis sp. Specifically, glucuronic acid (Glc-A) and N-acetyl-D-glucosamine (Glc-NAc) in BF-TB-EPS were 55% fold decreased and 1219% fold increased, respectively. Based on our findings, we proposed that these changes in monosaccharides composition might lead to a decreased biofilm formation efficiency of diatom.},
}
@article {pmid30034429,
year = {2018},
author = {Saba, T and Sajid, M and Khan, AA and Zahra, R},
title = {Role of Intracellular Adhesion icaAD and agr genes in Biofilm Formation in Clinical S. aureus Isolates and Assessment of Two Phenotypic Methods.},
journal = {Pakistan journal of medical sciences},
volume = {34},
number = {3},
pages = {633-637},
doi = {10.12669/pjms.343.14530},
pmid = {30034429},
issn = {1682-024X},
abstract = {Objective: To determine the role of icaAD and agr genes in biofilm formation and evaluate the consistency of two phenotypic methods for biofilm measurement.<br><br>Methods: A total of 81 clinical S. aureus strains were included and analyzed for biofilm formation by two methods. The microtitration plate method was optimized using computational fluid dynamics and compared with the Congo red assay. The genes for icaAD and agr were detected using PCR.<br><br>Results: Of 81 isolates, biofilm production was detected in 43% isolates using Congo red method while microtiter plate assay showed biofilm production in 92% isolates. Both methods showed correlation in 30% isolates. PCR detection showed icaAD gene in 42 (52%) isolates. Out of 81 S. aureus isolates 65 strains (80%) contained agr while 16 (20%) strains were non-typeable.<br><br>Conclusions: In conclusion, biofilm production was observed for both agr positive and agr negative isolates. Furthermore, the presence of icaAD genes was not associated with all biofilm producing strains as some strains negative for icaAD genes displayed biofilm production.},
}
@article {pmid30034372,
year = {2018},
author = {Zhu, X and Liu, D and Singh, AK and Drolia, R and Bai, X and Tenguria, S and Bhunia, AK},
title = {Tunicamycin Mediated Inhibition of Wall Teichoic Acid Affects Staphylococcus aureus and Listeria monocytogenes Cell Morphology, Biofilm Formation and Virulence.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1352},
doi = {10.3389/fmicb.2018.01352},
pmid = {30034372},
issn = {1664-302X},
abstract = {The emergence of bacterial resistance to therapeutic antibiotics limits options for treatment of common microbial diseases. Subinhibitory antibiotics dosing, often aid in the emergence of resistance, but its impact on pathogen's physiology and pathogenesis is not well understood. Here we investigated the effect of tunicamycin, a cell wall teichoic acid (WTA) biosynthesis inhibiting antibiotic at the subinhibitory dosage on Staphylococcus aureus and Listeria monocytogenes physiology, antibiotic cross-resistance, biofilm-formation, and virulence. Minimum inhibitory concentration (MIC) of tunicamycin to S. aureus and L. monocytogenes was 20-40 μg/ml and 2.5-5 μg/ml, respectively, and the subinhibitory concentration was 2.5-5 μg/ml and 0.31-0.62 μg/ml, respectively. Tunicamycin pre-exposure reduced cellular WTA levels by 18-20% and affected bacterial cell wall ultrastructure, cell membrane permeability, morphology, laser-induced colony scatter signature, and bacterial ability to form biofilms. It also induced a moderate level of cross-resistance to tetracycline, ampicillin, erythromycin, and meropenem for S. aureus, and ampicillin, erythromycin, vancomycin, and meropenem for L. monocytogenes. Pre-treatment of bacterial cells with subinhibitory concentrations of tunicamycin also significantly reduced bacterial adhesion to and invasion into an enterocyte-like Caco-2 cell line, which is supported by reduced expression of key virulence factors, Internalin B (InlB) and Listeria adhesion protein (LAP) in L. monocytogenes, and a S. aureus surface protein A (SasA) in S. aureus. Tunicamycin-treated bacteria or the bacterial WTA preparation suppressed NF-κB and inflammatory cytokine production (TNFα, and IL-6) from murine macrophage cell line (RAW 264.7) indicating the reduced WTA level possibly attenuates an inflammatory response. These results suggest that at the subinhibitory dosage, tunicamycin-mediated inhibition of WTA biosynthesis interferes with cell wall structure, pathogens infectivity and inflammatory response, and ability to form biofilms but promotes the development of antibiotic cross-resistance.},
}
@article {pmid30033670,
year = {2018},
author = {V Bondoc, KG and Lembke, C and Vyverman, W and Pohnert, G},
title = {Selective chemoattraction of the benthic diatom Seminavis robusta to phosphate but not to inorganic nitrogen sources contributes to biofilm structuring.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e00694},
doi = {10.1002/mbo3.694},
pmid = {30033670},
issn = {2045-8827},
abstract = {Diatoms frequently dominate marine and freshwater biofilms as major primary producers. Nutrient resources in these biofilms are patchily distributed and fluctuate dynamically over time. We recently reported that this spatially and temporally structured environment can be exploited by motile diatoms that use chemoattraction to dissolved silicate (dSi) under Si starvation. Here, we show that the behavioral response of diatoms is more complex and selective as cells are also responding to gradients of dissolved phosphate (dP) when starved in this nutrient. In contrast, neither nitrate nor ammonium (dN) triggers an attractive response under nitrogen limitation. Video monitoring and movement pattern analysis of the model diatom Seminavis robusta revealed that dP attraction is mediated by a combined chemokinetic and chemotactic response. After locating nutrient hotspots, the microalgae slow down and recover from the limitation. The fastest recovery in terms of growth was observed after dSi limitation. In agreement with the lack of directional response, recovery from dN limitation was slowest, indicating that no short-term benefit would be drawn by the algae from the location of transient hotspots of this resource. Our results highlight the ability of diatoms to adapt to nutrient limitation by active foraging and might explain their success in patchy benthic environments.},
}
@article {pmid30033309,
year = {2018},
author = {Naskar, A and Khan, H and Sarkar, R and Kumar, S and Halder, D and Jana, S},
title = {Anti-biofilm activity and food packaging application of room temperature solution process based polyethylene glycol capped Ag-ZnO-graphene nanocomposite.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {91},
number = {},
pages = {743-753},
doi = {10.1016/j.msec.2018.06.009},
pmid = {30033309},
issn = {1873-0191},
abstract = {Present work reports on synthesis and anti-biofilm activity as well as food packaging application of Ag-ZnO-reduce graphene oxide (rGO)-polyethylene glycol (PEG) (AZGP) nanocomposites via adopting room temperature solution process by varying silver nitrate content (up to 0.1 M) with fixed content of graphene oxide and PEG used in the precursors. Presence of Ag and ZnO nanoparticles (NPs) distributed uniformly over rGO nanosheets has been confirmed by X-ray diffraction and transmission electron microscopic analyses whereas FTIR, Raman, UV-Visible and X-ray photoelectron spectral studies have been performed to confirm the existence of chemical interaction/complexation that happened between the available oxygen functionalities of rGO and PEG with the inorganic moieties (Ag-ZnO/Zn2+) of AZGP samples. A formation mechanism of AZGP nanocomposite is proposed based on the experimental results. Anti-biofilm activity has been studied on Staphylococcus aureus and Pseudomonas aeruginosa bacteria to confirm the efficiency of the nanocomposites for killing the bacterial cells. It is found that 0.05 M silver nitrate based AZGP nanocomposite at 31.25 μg/mL sample dosage shows about 95% inhibition activity towards the biofilm formation as well as eradication of preformed biofilm. Also, agar based AZGP film has been fabricated and characterized by X-ray diffraction study for the purpose of food packaging application. Textural analysis of agar based film shows an enhanced film tensile strength. The film also shows an excellent antimicrobial activity even after keeping it for a prolong period of about 90 days. This cost effective simple synthesis strategy can make an avenue for development of Ag incorporated other biocompatible metal oxide based rGO-PEG nanocomposites for potential food packaging application.},
}
@article {pmid30032909,
year = {2018},
author = {Vysakh, A and Midhun, SJ and Jayesh, K and Jyothis, M and Latha, MS},
title = {Studies on biofilm formation and virulence factors associated with uropathogenic Escherichia coli isolated from patient with acute pyelonephritis.},
journal = {Pathophysiology : the official journal of the International Society for Pathophysiology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pathophys.2018.07.004},
pmid = {30032909},
issn = {0928-4680},
abstract = {The current study aims to the detection of pathogenic potential and virulence factor identification of uropathogenic Escherichia coli BRL-17 isolated from patients urine. The organism was isolated from the patient with chronic pyelonephritis. The identification of organism was done by analyzing gram staining, biochemical, 16S rDNA analysis, Raman microscopy and SEM analysis. The pathogenic potential was identified by multiplex PCR analysis of virulence factor genes like sfa, hly D, pap C. The biofilm forming ability was tested by congo red agar assay and tissue culture plate assay. The result of gram staining and biochemical analysis shows the characteristics of E-coli. The 16S rDNA analysis of the clinically isolated uropathogen showed 100% similarity with uropathogenic Escherichia coli strain. Raman microscopy and SEM confirms the organism as E-coli. The Multiplex PCR study identifies virulence genes like sfa, hly D, pap C in isolated E-coli. The presence of P fimbriae coded pap C gene, S fimbriae coded sfa gene and hemolysin-D coded hly D gene discloses its potential to cause urinary tract infection. Biofilm assay result enhances the organism's role as strong biofilm former. This biofilm forming ability of Escherichia coli strain BRL-17 made the organism to escape from host immune system and helps to colonize in bladder and kidney. This also helps to enhance the resistance to antibiotics. Our study confirms the organism as multidrug resistant, highly virulent, strong biofilm forming E-coli. The strain may be used for the development of animal models of pyelonephritis for the purpose of drug discovery.},
}
@article {pmid30032398,
year = {2018},
author = {Benslim, A and Mezaache-Aichour, S and Haichour, N and Aissat, K and Zerroug, MM},
title = {Biofilm formation and regulation of salicylic acid-inducible genes expression in Arabidopsis by Algerian indigenous bacteria from wheat and potatoes rhizospheres in semi-arid Sétif region.},
journal = {Archives of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00203-018-1556-5},
pmid = {30032398},
issn = {1432-072X},
support = {PNR project no: 1/u19/332//Ministère de l'Enseignement Supérieur et de la recherche scientifique, République de l'Algérie/ ; },
abstract = {45 bacterial isolates from potatoes and wheat rhizospheres near Sétif (Algeria) pre-selected for their antagonistic activity against three fungal plant pathogens, two necrotrophic Fusarium solani var. coeruleum and Phytophtora infestans, and a systemic F. oxysporum f. sp. albedinis. Molecular typing of the isolates showed abundance of Bacillus compared to Pseudomonas. Some of the tested strains have shown very high biofilm formation. Among the 24 Gram-positive bacilli screened for four cyclic lipopeptides genes, some isolates harbor two or more genes, while others have a single gene or have none. Four selected isolates were able to regulate the expression of six defense-related genes in Arabidopsis and produce salicylic acid. Upon the features assessed in this study, strain B. amyloliquefaciens A16 was selected for a subsequent use as seed treatment and biocontrol agent in semi-arid region fields. This strain showed important biofilm formation, regulation of Arabidopsis defenses, and harbored three cLPs genes.},
}
@article {pmid30031999,
year = {2018},
author = {Díez, S and Giaggio, R},
title = {Do biofilms affect the measurement of mercury by the DGT technique? Microcosm and field tests to prevent biofilm growth.},
journal = {Chemosphere},
volume = {210},
number = {},
pages = {692-698},
doi = {10.1016/j.chemosphere.2018.07.047},
pmid = {30031999},
issn = {1879-1298},
abstract = {The diffusive gradients in thin films (DGT) technique has been used routinely for monitoring the dissolved, bioavailable fraction of trace metals in freshwater during field campaigns. Nevertheless, for long deployment times, the biofilm formed on the filter of the DGT devices restricts trace metal uptake and hence interferes with the DGT measurements. In this work, we design different experiments to evaluate the potential of silver nanoparticles (AgNPs) in preventing the formation of biofilms on in-house manufactured mercury-specific DGTs. Laboratory tests were carried out by a microcosm system in independent glass containers, where biofilms obtained from field inocula were grown for weeks. Afterward, several experiments were performed with Hg-spiked river water, biofilms and DGTs treated and untreated with AgNPs to better understand biofilm colonization, inhibition and Hg uptake. The results showed that the treatment is very useful, since the mass of the biofilm accumulated at the surface of the treated DGT is significantly (p < 0.05) lower than in control (untreated) devices. Tests in colonized environments and Hg-spiked river water showed that the Hg uptake by the treated DGT matched the theoretical values and prevented biofilm formation up to 24 days post-deployment. Conversely, in deployments longer than two weeks using the untreated DGT, measurements could be underestimated by 35%. The results in the field reveal that in sampling stations with high levels of suspended matter, the filter becomes clogged despite there being no biofilm, thereby explaining its low efficiency for the uptake of Hg. In summary, the use of AgNPs inhibits biofilm formation and their use is especially recommended in eutrophic freshwaters with low amounts of suspended particulate matter.},
}
@article {pmid30031161,
year = {2018},
author = {Porter, SL and Coulter, SM and Pentlavalli, S and Thompson, TP and Laverty, G},
title = {Self-assembling diphenylalanine peptide nanotubes selectively eradicate bacterial biofilm infection.},
journal = {Acta biomaterialia},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.actbio.2018.07.033},
pmid = {30031161},
issn = {1878-7568},
abstract = {Biofilms present a major problem to industry and healthcare worldwide. Composed of a population of surface-attached microbial cells surrounded by a protective extracellular polysaccharide matrix, they are responsible for increased tolerance to antibiotics, treatment failure and a resulting rise in antimicrobial resistance. Here we demonstrate that self-assembled peptide nanostructures composed of a diphenylalanine motif provide sufficient antibacterial activity to eradicate mature biofilm forms of bacteria widely implicated in hospital infections. Modification of terminal functional groups to amino (-NH2), carboxylic acid (-COOH) or both modalities, and switch to d-isomers, resulted in changes in antibacterial selectivity and mammalian cell toxicity profiles. Of the three peptide nanotubes structures studied (NH2-FF-COOH, NH2-ff-COOH and NH2-FF-NH2), NH2-FF-COOH demonstrated the most potent activity against both planktonic (liquid, free-floating) and biofilm forms of bacteria, possessing minimal mammalian cell toxicity. NH2-FF-COOH resulted in greater than 3 Log10 CFU/mL viable biofilm reduction (>99.9%) at 5 mg/mL and total biofilm kill at 10 mg/mL against Staphylococcus aureus after 24 hours exposure. Scanning electron microscopy proved that antibiofilm activity was primarily due to the formation of ion channels and/or surfactant-like action, with NH2-FF-COOH and NH2-ff-COOH capable of degrading the biofilm matrix and disrupting cell membranes, leading to cell death in Gram-positive bacterial isolates. Peptide-based nanotubes are an exciting platform for drug delivery and engineering applications. This is the first report of using peptide nanotubes to eradicate bacterial biofilms and provides evidence of a new platform that may alleviate their negative impact throughout society.<br><br>STATEMENT OF SIGNIFICANCE: We outline, for the first time, the antibiofilm activity of diphenylalanine (FF) peptide nanotubes. Biofilm bacteria exhibit high tolerance to antimicrobials 10-10,000 times that of free-flowing planktonic forms. Biofilm infections are difficult to treat using conventional antimicrobial agents, leading to a rise in antimicrobial resistance. We discovered nanotubes composed of NH2-FF-COOH demonstrated potent activity against staphylococcal biofilms implicated in hospital infections, resulting in complete kill at concentrations of 10 mg/mL. Carboxylic acid terminated FF nanotubes were able to destroy the exopolysaccharide architecture of staphylococcal biofilms expressing minimal toxicity highlighting their potential for use in patients, whilst amidated (NH2-FF-NH2) forms demonstrated reduced antibiofilm efficacy and significant toxicity. These results contribute significantly to the development of innovative antibacterial technologies and peptide nanomaterials.},
}
@article {pmid30030225,
year = {2018},
author = {Thompson, CM and Marsden, AE and Tischler, AH and Koo, J and Visick, KL},
title = {A genetic analysis reveals that a trio of regulators prevents biofilm formation by Vibrio fischeri.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.01257-18},
pmid = {30030225},
issn = {1098-5336},
abstract = {Biofilms, complex communities of microorganisms surrounded by a self-produced matrix, facilitate attachment and provide protection to bacteria. A natural model used to study biofilm formation is the symbiosis between Vibrio fischeri and its host, the Hawaiian bobtail squid, Euprymna scolopes Host-relevant biofilm formation is a tightly regulated process and is only observed in vitro with strains that have been genetically manipulated to overexpress or disrupt specific regulators, primarily two-component signaling (TCS) regulators. These regulators control biofilm formation by dictating the production of the symbiosis polysaccharide (Syp-PS), the major component of the biofilm matrix. Control occurs both at and below the level of transcription of syp, the genes responsible for Syp-PS production. Here, we probed the roles of the two known negative regulators of biofilm formation, BinK and SypE, by generating double mutants. We also mapped and evaluated a point mutation using natural transformation and linkage analysis. We examined traditional biofilm formation phenotypes and established a new assay for evaluating the start of biofilm formation in the form of microscopic aggregates in shaking liquid cultures, in the absence of the known biofilm-inducing signal, calcium. We found that wrinkled colony formation is negatively controlled not only by BinK and SypE, but also by SypF. SypF is both required for and inhibitory to biofilm formation. Together, these data reveal that these three regulators are sufficient to prevent wild-type V. fischeri from forming biofilms under these conditions.Importance Bacterial biofilms promote attachment to a variety of surfaces and protect the constituent bacteria from environmental stresses, including antimicrobials. Understanding the mechanisms by which biofilms form will promote our ability to resolve them when they occur in the context of an infection. In this study, we found that Vibrio fischeri tightly controls biofilm formation using three negative regulators; the presence of a single one of these regulators was sufficient to prevent full biofilm development, while disruption of all three permitted robust biofilm formation. This work increases our understanding of the functions of specific regulators and demonstrates the substantial negative control that one benign microbe exerts over biofilm formation, potentially to ensure that it occurs only under the appropriate conditions.},
}
@article {pmid30030124,
year = {2018},
author = {Ionescu, AC and Cazzaniga, G and Ottobelli, M and Ferracane, JL and Paolone, G and Brambilla, E},
title = {In vitro biofilm formation on resin-based composites cured under different surface conditions.},
journal = {Journal of dentistry},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jdent.2018.07.012},
pmid = {30030124},
issn = {1879-176X},
abstract = {OBJECTIVES: The interfacial conditions occurring during light-curing procedures of resin-based composites (RBCs) influence their surface properties and therefore the biological behavior of the material. This study aimed to evaluate the influence of different surface curing conditions onin vitro biofilm formation by Streptococcus mutans and mixed oral microflora, in the presence or absence of surface salivary pre-conditioning.<br><br>METHODS: Two nanohybrid RBCs and four interfacial curing conditions (open air, argon, nitrogen and glycerin) were evaluated. Surface roughness (SR), surface elemental composition (energy-dispersive X-ray spectrometry, EDS) and biofilm formation (S. mutans and oral microcosm) were assessed. Surfaces were observed using scanning electron microscopy (SEM). Microbiological tests were performed with and without saliva pre-conditioning of the surfaces. EDS analysis was performed before and after biofilm formation, and biofilm morphology was evaluated using confocal laser scanning microscopy (CLSM). Data were analyzed using multi-way ANOVA and Tukey post-hoc test (p < 0.05).<br><br>RESULTS: Interfacial curing conditions significantly influenced SR depending on the tested RBC. EDS analysis showed that surface elemental composition was significantly influenced by the interfacial curing condition depending on the tested RBC. Interfacial curing conditions significantly influenced biofilm formation in both microbiological models in the absence of saliva pre-conditioning, depending on the tested RBC, whereas saliva pre-conditioning abrogated these affects.<br><br>CONCLUSIONS: Surface curing conditions significantly impacted biofilm formation in a material-dependent manner, which was abrogated when surfaces were pre-conditioned with saliva.<br><br>CLINICAL SIGNIFICANCE: Curing under glycerin did not improve the microbiological performances of the tested RBCs. These results, needing to be confirmed by in vivo data, have the potential to simplify operative procedures in restorative dentistry.},
}
@article {pmid30028928,
year = {2018},
author = {Braga, AS and Degand, GB and Pires, JG and Santos, DMSD and Magalhães, AC},
title = {Effect of oral antimicrobial mouthrinses containing alcohol on viability of Streptococcus mutans and microcosm biofilm and on the prevention of enamel caries lesions.},
journal = {American journal of dentistry},
volume = {31},
number = {3},
pages = {121-125},
pmid = {30028928},
issn = {0894-8275},
abstract = {PURPOSE: To evaluate the effect of PerioGard, Listerine, Noplak, Malvatricin and Cepacol commercial mouthrinses containing alcohol on the viability of Streptococcus mutans strain and of a microcosm biofilm and on the prevention of enamel demineralization.<br><br>METHODS: The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined against S. mutans (ATCC 25175). Microcosm biofilm formed from human saliva mixed with McBain saliva was created on bovine enamel for 5 days. From the 2nd to the 5th day, the enamel samples were exposed to McBain with 0.2% sucrose and to the mouthrinses (1 x 60 seconds). The biofilm viability was determined by fluorescence and the enamel demineralization by TMR.<br><br>RESULTS: The lowest MIC and MBC values were observed for Cepacol, while the highest values were found for Listerine. The mouthrinses significantly increased the number of dead bacteria in biofilm, varying from 38.0± 11.2% (Noplak) to 58.5± 13.9% (Listerine), compared to control (12.7± 10.6%), except Periogard (30.1± 12.4%). All mouthrinses reduced mineral loss (P< 0.0001), but only Noplak and Cepacol were able to significantly reduce lesion depth. Cepacol and Noplak presented the best anti-caries effect under this experimental model.<br><br>CLINICAL SIGNIFICANCE: This study shows that the anti-caries potential may vary between the commercial mouthrinses, which should be taken into account for their prescription.},
}
@article {pmid30028051,
year = {2018},
author = {Alzayer, YM and Gomez, GF and Eckert, GJ and Levon, JA and Gregory, RL},
title = {The Impact of Nicotine and Cigarette Smoke Condensate on Metabolic Activity and Biofilm Formation of Candida albicans on Acrylic Denture Material.},
journal = {Journal of prosthodontics : official journal of the American College of Prosthodontists},
volume = {},
number = {},
pages = {},
doi = {10.1111/jopr.12945},
pmid = {30028051},
issn = {1532-849X},
abstract = {PURPOSE: Smokers have increased denture stomatitis caused primarily by Candida albicans. The primary aim of this study was to demonstrate the impact of a wide range of nicotine and cigarette smoke condensate (CSC) concentrations on biofilm formation and metabolic activity of C. albicans on acrylic denture material.<br><br>MATERIALS AND METHODS: C. albicans (ATCC strain 10231) was used. Standardized denture acrylic (PMMA) specimens (total of 135 specimens) were incubated with C. albicans and exposed to nicotine and CSC at different concentrations (0, 0.25, 0.5, 1, 2, 4, 8, 16, and 32 mg/ml) and (0, 0.25, 0.5, 1, 2, and 4 mg/ml), respectively. For each experiment, 3 samples per nicotine and CSC concentration and a total of 45 specimens (27 specimens for the nicotine and 18 specimens for the CSC-treated samples) were used and were selected randomly for each group. The control group consisted of 0 mg/ml of nicotine or CSC. The viability of C. albicans was measured using spiral plating on blood agar plates. The effect of nicotine and CSC concentrations on planktonic cells was were measured using a microplate reader. Metabolic activity of 24-hour-old established C. albicans biofilm exposed to nicotine and CSC for 24 hours in microtiter plates was determined using a 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-carboxanilide (XTT) reduction assay.<br><br>RESULTS: The viability of C. albicans increased concomitant with increasing concentrations of CSC and nicotine, particularly at 0.5 and 2 mg/ml, respectively. Concentrations of CSC and nicotine above this resulted in an inhibitory effect on C. albicans viability. CSC and nicotine at 4 and 16 mg/ml, respectively, increased C. albicans biofilm metabolic activity.<br><br>CONCLUSION: Nicotine and CSC up to certain concentrations caused increases in biofilm formation, metabolic activity, viability, and planktonic cell absorbance of C. albicans. This in vitro study demonstrates the effectiveness of tobacco on promoting the growth of C. albicans and suggests their potential contributing factor in C. albicans biofilm related infections in smokers.},
}
@article {pmid30026732,
year = {2018},
author = {Pompilio, A and Geminiani, C and Bosco, D and Rana, R and Aceto, A and Bucciarelli, T and Scotti, L and Di Bonaventura, G},
title = {Electrochemically Synthesized Silver Nanoparticles Are Active Against Planktonic and Biofilm Cells of Pseudomonas aeruginosa and Other Cystic Fibrosis-Associated Bacterial Pathogens.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1349},
doi = {10.3389/fmicb.2018.01349},
pmid = {30026732},
issn = {1664-302X},
abstract = {A novel, electrochemically synthesized, silver nanoparticles (AgNPs) formulation was evaluated in vitro against Pseudomonas aeruginosa, Burkholderia cepacia, Stenotrophomonas maltophilia, and Staphylococcus aureus strains from cystic fibrosis (CF) patients. AgNPs were particularly active against P. aeruginosa and B. cepacia planktonic cells (median MIC: 1.06 and 2.12 μg/ml, respectively) by a rapid, bactericidal and concentration-dependent effect. AgNPs showed to be particularly effective against P. aeruginosa and S. aureus biofilm causing a viability reduction ranging from 50% (1×MIC) to >99.9% (4×MIC). Electron microscopy showed that AgNPs deconstruct extracellular matrix of P. aeruginosa biofilm, and accumulate at the cell surface causing cell death secondary to membrane damage. Compared to Tobramycin, AgNPs showed comparable, or even better, activity against planktonic and biofilm P. aeruginosa cells. AgNPs at concentrations effective against B. cepacia and P. aeruginosa were not toxic to G. mellonella larvae. Our silver-based formulation might be an alternative to antibiotics in CF patients. Further in vitro and in vivo studies are warranted to confirm this therapeutic potential.},
}
@article {pmid30026003,
year = {2018},
author = {Ledwoch, K and Dancer, SJ and Otter, JA and Kerr, K and Roposte, D and Maillard, JY},
title = {Beware Biofilm! Dry biofilms containing bacterial pathogens on multiple healthcare surfaces; a multicentre study.},
journal = {The Journal of hospital infection},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jhin.2018.06.028},
pmid = {30026003},
issn = {1532-2939},
abstract = {BACKGROUND: Wet biofilms associated with medical devices have been widely studied and their link with healthcare associated infections (HCAIs) is well recognised. Little attention has been paid to the presence of dry biofilms on environmental surfaces in healthcare settings.<br><br>AIM: To investigate the occurrence, prevalence, and diversity of dry biofilms on hospital surfaces.<br><br>METHOD: 61 terminally cleaned items were received from three different UK hospitals. The presence of dry biofilm was investigated using culture-based methods and scanning electron microscopy (SEM). Bacterial diversity within biofilms was investigated using RISA-PCR and next generation sequencing.<br><br>FINDINGS: Multi-species dry biofilms were recovered from 95% of 61 samples. Abundance and complexity of dry biofilms were confirmed by SEM. All biofilms harboured Gram-positive bacteria including pathogens associated with HCAIs; 58% of samples grew meticillin-resistant Staphylococcus aureus (MRSA). Dry biofilms had similar physical composition regardless of the type of items sampled or the ward from which the samples originated. There were differences observed in the dominance of particular species: dry biofilms from two hospitals contained mostly staphylococcal DNA, whereas more Bacillus spp. DNA was found on surfaces from the third hospital.<br><br>CONCLUSION: The presence of dry biofilms harbouring bacterial pathogens is virtually universal on commonly used items in healthcare settings. The role of dry biofilms in spreading HCAIs may be underestimated. The risk may be further exacerbated by inefficient cleaning and disinfection practices for hospital surfaces.},
}
@article {pmid30023647,
year = {2017},
author = {Bagchi, D and Dutta, S and Singh, P and Chaudhuri, S and Pal, SK},
title = {Essential Dynamics of an Effective Phototherapeutic Drug in a Nanoscopic Delivery Vehicle: Psoralen in Ethosomes for Biofilm Treatment.},
journal = {ACS omega},
volume = {2},
number = {5},
pages = {1850-1857},
doi = {10.1021/acsomega.7b00187},
pmid = {30023647},
issn = {2470-1343},
abstract = {Appropriate localization of a drug and its structure/functional integrity in a delivery agent essentially dictates the efficacy of the vehicle and the medicinal activity of the drug. In the case of a phototherapeutic drug, its photoinduced dynamics becomes an added parameter. Here, we have explored the photoinduced dynamical events of a model phototherapeutic drug psoralen (PSO) in a potential delivery vehicle called an ethosome. Dynamic light scattering confirms the structural integrity of the ethosome vehicle after the encapsulation of PSO. Steady state and picosecond resolved polarization gated spectroscopy, including the well-known strategy of solvation and Förster resonance energy transfer, reveal the localization of the drug in the vehicle and the environment in the proximity of PSO. We have also investigated the efficacy of drug delivery to various individual bacteria (Gram-negative: Escherichia coli; Gram-positive: Staphylococcus aureus) and bacterial biofilms. Our optical and electron microscopic studies reveal a significant reduction in bacterial survival (∼70%) and the destruction of bacterial adherence following a change in the morphology of the biofilms after phototherapy. Our studies are expected to find relevance in the formulation of drug delivery agents in several skin diseases and biofilm formation in artificial implants.},
}
@article {pmid30025265,
year = {2018},
author = {Long, M and Ilhan, ZE and Xia, S and Zhou, C and Rittmann, BE},
title = {Complete dechlorination and mineralization of pentachlorophenol (PCP) in a hydrogen-based membrane biofilm reactor (MBfR).},
journal = {Water research},
volume = {144},
number = {},
pages = {134-144},
doi = {10.1016/j.watres.2018.06.071},
pmid = {30025265},
issn = {1879-2448},
abstract = {Complete biodegradation and mineralization of pentachlorophenol (PCP), a priority pollutant in water, is challenging for water treatment. In this study, a hydrogen (H2)-based membrane biofilm reactor (MBfR) was applied to treat PCP, along with nitrate and sulfate, which often coexist in contaminated groundwater. Throughout 120-days of continuous operation, almost 100% of up to 10 mg/L PCP was removed with minimal intermediate accumulation and in parallel with complete denitrification of 20 mg-N/L nitrate. PCP initially was reductively dechlorinated to phenol, which was then mineralized to CO2 through pathways that began with aerobic activation via monooxygenation by Xanthobacter and anaerobic activation via carboxylation by Azospira and Thauera. Sulfur cycling induced by SO42- reduction affected the microbial community: The dominant bacteria became sulfate-reducers Desulfomicrobium, sulfur-oxidizers Sulfuritalea and Flavobacterium. This study provides insights and a promising technology for bioremediation of water contaminated with PCP, nitrate, and sulfate.},
}
@article {pmid30024592,
year = {2018},
author = {Liu, K and Hou, BX},
title = {The regulation of DLTA gene in bacterial growth and biofilm formation by Parvimonas micra.},
journal = {European review for medical and pharmacological sciences},
volume = {22},
number = {13},
pages = {4033-4044},
pmid = {30024592},
issn = {2284-0729},
abstract = {OBJECTIVE: To evaluate the effect of dltA-deficient mutant on the bacterial growth and biofilm formation by P. micra ATCC 33270. Parvimonas micra contributes to many human polymicrobial infections, and is common in dental plaque biofilms of patients with periodontal and endodontic conditions. Lipoteichoic acid (LTA) performs several functions in gram-positive bacteria, including maintenance of cationic homeostasis and modulation of autolytic activities. The activation of dltA gene expression protects LTA expressing gram-positive bacteria from innate immune anti-microbial defense.<br><br>MATERIALS AND METHODS: Deficient mutant of the dltA gene was created from P. micra ATCC 33270 by homologous recombination. Colony-forming units (CFUs) and turbidity helped estimate the growth of P. micra. Crystal violet staining, Confocal Scanning Laser Microscopy (CSLM) and Scanning Electron Microscopy (SEM) evaluated biofilm mass and structure.<br><br>RESULTS: P. micra ATCC 33270 with dltA-deficient mutant was successfully established. CFUs of the wild-type strains were significantly higher than that of the dltA-deficient mutant strains after 24 h, 48 h, 72 h and 7 d culture (all p < 0.05). The growth rate of dltA-deficient mutant strains was significantly lower than their wild-type counterparts. Furthermore, crystal violet staining showed that the dltA mutant formed significantly less biofilm as compared to wild-type strains. The dltA-deficient mutant synthesized a thin and incomplete biofilm after incubation for 48 h. With increasing incubation time, all biofilm units were seen to shrink, and this structure almost disappeared after 7 days of culture as observed by CSLM and SEM.<br><br>CONCLUSIONS: The dltA gene is associated with bacterial growth and biofilm formation by P. micra ATCC 33270.},
}
@article {pmid30024267,
year = {2018},
author = {Korabliovienė, J and Mauricas, M and Ambrozevičienė, Č and Valius, M and Kaupinis, A and Čaplinskas, S and Korabliov, P},
title = {Mycobacteria produce proteins involved in biofilm formation and growth-affecting processes.},
journal = {Acta microbiologica et immunologica Hungarica},
volume = {},
number = {},
pages = {1-14},
doi = {10.1556/030.65.2018.033},
pmid = {30024267},
issn = {1217-8950},
abstract = {The aim of this study was to determine the effect of mycobacterial proteins on mycobacterial biofilm formation and growth processes. We separated growth-affecting proteins (GEPs) from wild type of Mycobacterium bovis and ATCC strain of Mycobacterium avium subsp. avium. Our results showed that these mycobacteria-secreted GEPs are involved in biofilm formation, growth stimulatory, and inhibitory processes. Our findings suggest that GEP stimulated M. avium subsp. avium growth in vitro. Stimulation process was observed in mycobacteria affected with GEP extracted from M. avium subsp. avium. We found that both GEPs inhibited the growth of the M. bovis. Optical density measurement and visual analysis confirm that GEP plays an important role in biofilm formation process. Most of M. bovis GEP are associated with the type VII secretion and general secretion pathways. Our results contribute to a better understanding of the mechanisms underlying mycobacterial biofilm formation and growth-affecting processes and better characterization of mycobacterial proteins and their functions. It is noteworthy that this finding represents the first demonstration of GEP-mediated growth effects on a solid and liquid medium.},
}
@article {pmid30023786,
year = {2018},
author = {Sambalova, O and Thorwarth, K and Heeb, NV and Bleiner, D and Zhang, Y and Borgschulte, A and Kroll, A},
title = {Carboxylate Functional Groups Mediate Interaction with Silver Nanoparticles in Biofilm Matrix.},
journal = {ACS omega},
volume = {3},
number = {1},
pages = {724-733},
doi = {10.1021/acsomega.7b00982},
pmid = {30023786},
issn = {2470-1343},
abstract = {Biofilms causing medical conditions or interfering with technical applications can prove undesirably resistant to silver nanoparticle (AgNP)-based antimicrobial treatment, whereas beneficial biofilms may be adversely affected by the released silver nanoparticles. Isolated biofilm matrices can induce reduction of silver ions and stabilization of the formed nanosilver, thus altering the exposure conditions. We thus study the reduction of silver nitrate solution in model experiments under chemically defined conditions as well as in stream biofilms. Formed silver nanoparticles are characterized by state-of-the art methods. We find that isolated biopolymer fractions of biofilm organic matrix are capable of reducing ionic Ag, whereas other isolated fractions are not, meaning that biopolymer fractions contain both reducing agent and nucleation seed sites. In all of the investigated systems, we find that silver nanoparticle-biopolymer interface is dominated by carboxylate functional groups. This suggests that the mechanism of nanoparticle formation is of general nature. Moreover, we find that glucose concentration within the biofilm organic matrix correlates strongly with the nanoparticle formation rate. We propose a simple mechanistic explanation based on earlier literature and the experimental findings. The observed generality of the extracellular polymeric substance/AgNP system could be used to improve the understanding of impact of Ag+ on aqueous ecosystems, and consequently, to develop biofilm-specific medicines and bio-inspired water decontaminants.},
}
@article {pmid30023754,
year = {2017},
author = {Freudenthal, O and Quilès, F and Francius, G},
title = {Discrepancies between Cyclic and Linear Antimicrobial Peptide Actions on the Spectrochemical and Nanomechanical Fingerprints of a Young Biofilm.},
journal = {ACS omega},
volume = {2},
number = {9},
pages = {5861-5872},
doi = {10.1021/acsomega.7b00644},
pmid = {30023754},
issn = {2470-1343},
abstract = {Antimicrobial peptides (AMPs) are currently known for their potential as an alternative to conventional antibiotics and new weapons against drug-resistant bacteria and biofilms. In the present work, the mechanism of action of a cyclic (colistin) and a linear (catestatin) AMP on a young E. coli biofilm was deciphered from the molecular to the cellular scale. To this end, infrared spectroscopy (attenuated total reflection-Fourier transform infrared) assisted by chemometric analysis was combined with fluorescence and atomic force microscopies to address the very different behaviors of both AMPs. Indeed, the colistin dramatically damaged the bacterial cell wall and the metabolism even though its action was not homogeneous over the whole bacterial population and repopulation can be observed after peptide removal. Conversely, catestatin did not lead to major damages in the bacterial morphology but its action was homogeneous over the whole bacterial population and the cells were unable to regrow after the peptide treatment. Our results strongly suggested that contrary to the cyclic molecule, the linear one is able to cause irreversible damages in the bacterial membrane concomitantly to a strong impact on the bacterial metabolism.},
}
@article {pmid30023683,
year = {2017},
author = {Yadav, N and Dubey, A and Shukla, S and Saini, CP and Gupta, G and Priyadarshini, R and Lochab, B},
title = {Graphene Oxide-Coated Surface: Inhibition of Bacterial Biofilm Formation due to Specific Surface-Interface Interactions.},
journal = {ACS omega},
volume = {2},
number = {7},
pages = {3070-3082},
doi = {10.1021/acsomega.7b00371},
pmid = {30023683},
issn = {2470-1343},
abstract = {Graphene oxide (GO) is a promising and remarkable nanomaterial that exhibits antimicrobial activity due to its specific surface-interface interactions. In the present work, for the first time, we have reported the antibacterial activity of GO-coated surfaces prepared by two different methods (Hummers' and improved, i.e., GOH and GOI) against bacterial biofilm formation. The bacterial toxicity of the deposited GO-coated surfaces was investigated for both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) models of bacteria. The mechanism of inhibition is different on the coated surface than that in suspension, as determined by measurement of the percentage inhibition of biofilm formation, Ellman's assay, and colony forming unit (CFU) studies. The difference in the nature, degree of oxidative functionalities, and size of the synthesized GO nanoparticles mitigates biofilm formation. To better understand the antimicrobial mechanism of GO when coated on surfaces, we were able to demonstrate that beside reactive oxygen species-mediated oxidative stress, the physical properties of the GO-coated substrate effectively inactivate bacterial cell proliferation, which forms biofilms. Light and atomic force microscopy (AFM) images display a higher inhibition in the proliferation of planktonic cells in Gram-negative bacteria as compared to that in Gram-positive bacteria. The existence of a smooth surface with fewer porous domains in GOI inhibits biofilm formation, as demonstrated by optical microscopy and AFM images. The oxidative stress was found to be lower in the coated surface as compared to that in the suspensions as the latter enables exposure of both a large fraction of the active edges and functionalities of the GO sheets. In suspension, GOH is selective against S. aureus whereas GOI showed inhibition toward E. coli. This study provides new insights to better understand the bactericidal activity of GO-coated surfaces and contributes to the design of graphene-based antimicrobial surface coatings, which will be valuable in biomedical applications.},
}
@article {pmid30022542,
year = {2018},
author = {Ardon, CB and Prens, EP and Fuursted, K and Ejaz, RN and Shailes, J and Jenssen, H and Jemec, GBE},
title = {Biofilm production and antibiotic susceptibility of Staphylococcus epidermidis strains from Hidradenitis Suppurativa lesions.},
journal = {Journal of the European Academy of Dermatology and Venereology : JEADV},
volume = {},
number = {},
pages = {},
doi = {10.1111/jdv.15183},
pmid = {30022542},
issn = {1468-3083},
abstract = {BACKGROUND: An aberrant interaction between commensal skin bacteria and the host skin immune system is considered important in the pathogenesis of Hidradenitis Suppurativa (HS).<br><br>OBJECTIVE: In this study we investigated the antibiotic susceptibility and biofilm-forming capabilities of S. epidermidis strains isolated from HS patients.<br><br>METHODS: Skin biopsies were taken from active HS lesions such as inflammatory nodules and/or sinuses and non-involved skin from 26 patients and cultured under optimal microbiological conditions for 24 hours. Planktonic growth, biofilm production, antibiotic susceptibility, and biofilm eradication by clindamycin, doxycycline, rifampicin, tetracycline, were tested including a laboratory control strain of S. epidermidis for reference.<br><br>RESULTS: S. epidermidis was cultured in 16 out of 26 HS patients (62%). In total 27 different S. epidermidis isolates were identified; 16 (59%) from non-involved skin and 11 (41%) from HS lesions. All bacterial strains showed planktonic growth. Twenty-four out of 27 (89%) isolates were strong biofilm producers in vitro. The biofilm-forming capability varied amongst the strains from non-involved skin and lesional skin. Twenty-four strains had an intermediate to resistant antibiotic susceptibility to clindamycin (89%). Rifampicin was the most effective antibiotic at inhibiting planktonic growth and at eradication of biofilm (p<0.05).<br><br>CONCLUSION: We observed a slight increase in S. epidermidis virulence, characterized by resistance to commonly used antibiotics, increased biofilm production, and resistance to biofilm eradication. Especially the reduced sensitivity to tetracycline and clindamycin, two standard antibiotics in the treatment of HS is alarming. Rifampicin, also important in HS treatment, showed the greatest efficacy at eradicating the biofilm at low MIC concentrations. This article is protected by copyright. All rights reserved.},
}
@article {pmid30022269,
year = {2018},
author = {Jardine, AP and Montagner, F and Quintana, RM and Zaccara, IM and Kopper, PMP},
title = {Antimicrobial effect of bioceramic cements on multispecies microcosm biofilm: a confocal laser microscopy study.},
journal = {Clinical oral investigations},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00784-018-2551-6},
pmid = {30022269},
issn = {1436-3771},
abstract = {OBJECTIVES: To assess the viability of multispecies microcosm biofilm after contact with NeoMTA Plus, Biodentine, and MTA Angelus.<br><br>MATERIALS AND METHODS: Fifty-four human dentin blocks (4 × 5 × 4 mm) were allocated to Hawley retainers, worn by six volunteers for 72 h. The blocks were then individually incubated in BHI broth for 21 days at 37 °C. At the end of experimental time for biofilm growth, the samples were randomly divided into four groups (n = 12): NeoMTA Plus, Biodentine, MTA Angelus, and negative control. The materials were placed in contact with the blocks. All samples were placed in cell-culture plate wells and incubated in BHI broth for 7 days at 37 °C. One sample from each volunteer (n = 6) was analyzed by SEM to describe the biofilm morphology. CLSM was performed to determine the percentage of viable biofilm biovolume. The data were statistically analyzed by one-way ANOVA and Tukey's multiple comparison test (α = 5%).<br><br>RESULTS: SEM showed biofilm formed by spherical and rod-shaped bacteria surrounded by an extracellular matrix. No material was able to kill all biofilm cells, and all groups had more than 50% of viable bacteria. NeoMTA Plus was significantly different from the negative control group (P < .05).<br><br>CONCLUSIONS: All tested materials were not effective against multispecies microcosm biofilm.<br><br>CLINICAL RELEVANCE: NeoMTA Plus, Biodentine, and MTA Angelus were not effective against multispecies microcosm biofilm. It is essential to understand that these bioceramic cements are indicated for infected clinical situations. Thus, complementary disinfection procedures should be conducted prior to filling with these materials.},
}
@article {pmid30021200,
year = {2018},
author = {Maske, TT and Kuper, NK and Cenci, MS and Huysmans, MDNJM},
title = {Chlorhexidine, a Matrix Metalloproteinase Inhibitor and the Development of Secondary Caries Wall Lesions in a Microcosm Biofilm Model.},
journal = {Caries research},
volume = {53},
number = {1},
pages = {107-117},
doi = {10.1159/000490195},
pmid = {30021200},
issn = {1421-976X},
abstract = {This study investigated the role of a matrix metalloproteinase (MMP) inhibitor (CHX 2%) in the development of secondary caries wall lesions in different interface conditions with small (run 1) and wider gaps (run 2). Dentin discs were restored and pretreated with or without CHX 2%. In run 1, interfaces were made with gaps of 30, 60, or 90 µm. Interfaces with composite placed directly onto the dentin were either bonded (Adper Single Bond 2) or not bonded. In run 2, interfaces were made with gaps of 100 µm, with or without adhesive on the composite side (CLEARFIL SE Bond). Interfaces were either bonded or not bonded, as in run 1. Microcosm biofilms were grown on dentin-composite samples for 14 days. Caries lesion outcomes were analyzed by transversal wavelength-independent microradiography at 3 locations: the outer surface, and the interface wall at a distance of 200 and 500 µm from the gap entrance. Linear regression analyses showed that pretreatment with MMP inhibitor did not influence progression of the wall lesion at any location (p ≥ 0.218). Interfaces with intentional gaps showed positive and significant effect on the wall lesion progression at 200 µm from the gap entrance (p ≤ 0.005). A small trend of increase in wall lesion development was observed at the 200-µm location when bonding was present on the composite side. In conclusion, the dentin pretreatment with CHX 2% was not able to slow down the development of secondary caries wall lesions in small and wide gaps in this biofilm model.},
}
@article {pmid30018971,
year = {2018},
author = {Cerioli, MF and Moliva, MV and Cariddi, LN and Reinoso, EB},
title = {Effect of the Essential Oil of Minthostachys verticillata (Griseb.) Epling and Limonene on Biofilm Production in Pathogens Causing Bovine Mastitis.},
journal = {Frontiers in veterinary science},
volume = {5},
number = {},
pages = {146},
doi = {10.3389/fvets.2018.00146},
pmid = {30018971},
issn = {2297-1769},
abstract = {Bovine mastitis causes large annual economic losses around the world. Different microorganisms are associated with the disease. The capacity of pathogens to adhere to bovine mammary epithelial cells is associated with biofilm production which leads to antibiotic resistance. Research is now leading to search alternative control methods and medicinal plants constitute a natural, safe, effective and inexpensive option. Minthostachys verticillata is an autochthonous medicinal plant of Argentina with multiple ethnobotanical properties. In a previous study, we demonstrated that the essential oil (EO) of this species and limonene, one of its compounds, inhibited the growth of mastitis pathogens. The objective of the present work was to determine the inhibitory effect of the essential oil of M. verticillata and limonene, on biofilm formation and on mature biofilm produced by pathogens isolated from bovine mastitis. Time kill assay and bacterial lysis were also determined. Furthermore, RAPD-PCR assays were performed to determine changes in bacterial DNA after EO and limonene exposition. Bacterial isolates were identified as Escherichia coli (EC3 and EC9), Bacillus pumilus (BP5, BP6, and BP7) and Enterococcus faecium (EF1) by rRNA 16S sequencing and MALDI-TOF MS. All the strains were able to form biofilm. Addition of both lactose and sucrose did not affect biofilm production. MIC values for EO were 3.6 mg/ml for E. faecium; 0.9 mg/ml for E. coli (EC3), 14.5 mg/ml for E. coli (EC9), 1.8 mg/ml for B. pumilus (BP7), 3.63 mg/ml for B. pumilus (BP6) and 29.0 mg/ml for B. pumilus (BP7). MIC values for limonene were 6.6 mg/ml for B. pumilus (BP6) and 105 mg/ml for B. pumilus (BP5). These results demonstrated that EO was more effective than limonene, showing also bactericidal action against E. faecium (minimal inhibitory concentration (MBC) = 29.0 mg/ml). This result was corroborated by time of death assay, observing a cell decrease after at 6 h, and then by bacterial lysis assay. Both EO and limonene affected mature biofilm of isolated strains. The results contribute to the study of EO and limonene which may serve as a therapy against bovine mastitis pathogens inhibiting the development of pathogenic bacteria.},
}
@article {pmid30018606,
year = {2018},
author = {Wilkinson, HN and Iveson, S and Catherall, P and Hardman, MJ},
title = {A Novel Silver Bioactive Glass Elicits Antimicrobial Efficacy Against Pseudomonas aeruginosa and Staphylococcus aureus in an ex Vivo Skin Wound Biofilm Model.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1450},
doi = {10.3389/fmicb.2018.01450},
pmid = {30018606},
issn = {1664-302X},
abstract = {Biofilm infection is now understood to be a potent contributor to the recalcitrant nature of chronic wounds. Bacterial biofilms evade the host immune response and show increased resistance to antibiotics. Along with improvements in antibiotic stewardship, effective new anti-biofilm therapies are urgently needed for effective wound management. Previous studies have shown that bioactive glass (Bg) is able to promote healing with moderate bactericidal activity. Here we tested the antimicrobial efficacy of a novel BG incorporating silver (BgAg), against both planktonic and biofilm forms of the wound-relevant bacteria Pseudomonas aeruginosa and Staphylococcus aureus. BgAg was stable, long lasting, and potently effective against planktonic bacteria in time-kill assays (6-log reduction in bacterial viability within 2 h) and in agar diffusion assays. BgAg reduced bacterial load in a physiologically relevant ex vivo porcine wound biofilm model; P. aeruginosa (2-log reduction) and S. aureus (3-log reduction). BgAg also conferred strong effects against P. aeruginosa biofilm virulence, reducing both protease activity and virulence gene expression. Co-culture biofilms appeared more resistant to BgAg, where a selective reduction in S. aureus was observed. Finally, BgAg was shown to benefit the host response to biofilm infection, directly reducing host tissue cell death. Taken together, the findings provide evidence that BgAg elicits potent antimicrobial effects against planktonic and single-species biofilms, with beneficial effects on the host tissue response. Further investigations are required to elucidate the specific consequences of BG administration on polymicrobial biofilms, and further explore the effects on host-microbe interactions.},
}
@article {pmid30016175,
year = {2018},
author = {Cattò, C and Villa, F and Cappitelli, F},
title = {Recent progress in bio-inspired biofilm-resistant polymeric surfaces.},
journal = {Critical reviews in microbiology},
volume = {},
number = {},
pages = {1-20},
doi = {10.1080/1040841X.2018.1489369},
pmid = {30016175},
issn = {1549-7828},
abstract = {Any surface of human interest can serve as a substrate for biofilm growth, sometimes with detrimental effects. The social and economic consequences of biofilm-mediated damage to surfaces are significant, the financial impact being estimated to be billions of dollars every year. After describing traditional biocide-based approaches for the remediation of biofilm-affected surfaces, this review deals with more recent developments in material science, focusing on non-toxic, eco-sustainable nature-inspired biomaterials with anti-biofilm properties superior to the conventional biocide-based approaches in terms of addressing the biofilm problem.},
}
@article {pmid30015461,
year = {2018},
author = {Guan, CP and Luo, HX and Fang, HE and Zhou, XZ},
title = {Global Transcriptome Changes of Biofilm-Forming Staphylococcus epidermidis Responding to Total Alkaloids of Sophorea alopecuroides.},
journal = {Polish journal of microbiology},
volume = {67},
number = {2},
pages = {223-226},
doi = {10.21307/pjm-2018-024},
pmid = {30015461},
issn = {1733-1331},
abstract = {Transcriptome changes of biofilm-forming Staphylococcus epidermidis response to total alkaloids of Sophorea alopecuroides was observed. Bioinformatic analyses were further used to compare the differential gene expression between control and the treated samples. It was found that 282 genes were differentially expressed, with 92 up-regulated and 190 down-regulated. These involved down-regulation of the sulfur metabolism pathway. It was suggested that inhibitory effects on Staphylococcus epidermidis and its biofilm formation of the total alkaloids of S. alopecuroides was mainly due to the regulation of the sulfur metabolism pathways of S. epidermidis.},
}
@article {pmid30015218,
year = {2018},
author = {Gondim, BLC and Castellano, LRC and de Castro, RD and Machado, G and Carlo, HL and Valença, AMG and de Carvalho, FG},
title = {Effect of chitosan nanoparticles on the inhibition of Candida spp. biofilm on denture base surface.},
journal = {Archives of oral biology},
volume = {94},
number = {},
pages = {99-107},
doi = {10.1016/j.archoralbio.2018.07.004},
pmid = {30015218},
issn = {1879-1506},
abstract = {OBJECTIVES: Chitosan nanoparticles (ChNPs) have antifungal effects, however there is a lack of information about the effects of ChNPs against Candida biofilm on denture base surface. This study investigated the ChNPs effect against C. albicans biofilm adhesion and formation, and against Candida spp. biofilm on heat-cured acrylic resin.<br><br>DESIGN: The ChNPs were synthetized (3800 μg/mL) and characterized by infra-red spectrophotometry and transmission electron microscopy. The minimum inhibitory/fungicidal concentrations (MIC/MFC) against Candida spp. were determined. The time-kill assay and changes on C. albicans micromorphology were evaluated. The % inhibition of ChNPs on C. albicans biofilm formation and reduction were investigated using 1 min and 8 h exposure. Candida biofilm was developed on resin surfaces and ChNPs were applied every 8 h for 5 days. After, fungal cells were counted (CFU/mL) and the surface roughness (Ra) and vickers microhardness (HV) of resin were analysed. For all experiments, sodium hypochlorite (NaOCl) was used as control. Data were analyzed by ANOVA, Tukey and paired t-tests (α = 0.05).<br><br>RESULTS: The MIC80% of ChNPs was 30.1 μg/mL. ChNPs at 4 MIC showed complete inhibition in the time-kill assays. Blastoconidia cells were predominant after ChNPs application. The % inhibition ChNPs on C. albicans was proportional to its concentration, regardless of the exposure time. ChNPs decreased the CFU/mL of Candida spp. and showed lower alteration of HV and Ra values of resin surface compared to NaOCl.<br><br>CONCLUSIONS: The ChNPs inhibited C. albicans biofilm, reduced Candida biofilm on resin and caused small changes in roughness and hardness of acrylic resin surface.},
}
@article {pmid30015141,
year = {2018},
author = {Subramaniyan, SB and Ramani, A and Ganapathy, V and Anbazhagan, V},
title = {Preparation of self-assembled platinum nanoclusters to combat Salmonella typhi infection and inhibit biofilm formation.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {171},
number = {},
pages = {75-84},
doi = {10.1016/j.colsurfb.2018.07.023},
pmid = {30015141},
issn = {1873-4367},
abstract = {In this work, phytoprotein functionalized platinum nanoparticles (PtNCs) were synthesized using the proteins from fresh green spinach leaves. Transmission electron microscopy showed that PtNCs were spherical shape with size ∼5 nm, which self assembled into spherical platinum nanoclustures (PtNCs) with size within the range of 100-250 nm. The presence of elemental platinum was confirmed by EDX analysis. FTIR studies confirm that the PtNCs were stabilized by the protein. As prepared PtNCs inhibits the growth of the food borne pathogen, Salmonella typhi with minimum inhibitory concentration (MIC) of 12.5 μM. Light microscopy evidenced that the PtNCs can damage the established biofilms. Antibacterial mechanistic study revealed that PtNCs damages the S. typhi membranes, which was confirmed by scanning electron microscopy and further by fluorescence microscopy using acridine orange/propidium iodide dual staining assay. Besides membrane damage, PtNCs also triggered the intracellular ROS-mediated oxidative damage over the antioxidant defense and kills S. typhi. The hemolytic test showed low cytotoxicity of PtNCs at 100 μM (four times higher the MIC). Finally, the therapeutic efficacy of PtNCs was validated in S. typhi infected zebrafish animal model and the obtained results are discussed.},
}
@article {pmid30014501,
year = {2018},
author = {Torabi Delshad, S and Soltanian, S and Sharifiyazdi, H and Bossier, P},
title = {Effect of quorum quenching bacteria on growth, virulence factors and biofilm formation of Yersinia ruckeri in vitro and an in vivo evaluation of their probiotic effect in rainbow trout.},
journal = {Journal of fish diseases},
volume = {},
number = {},
pages = {},
doi = {10.1111/jfd.12840},
pmid = {30014501},
issn = {1365-2761},
abstract = {Five N-acyl homoserine lactone-degrading bacteria (quorum quenching (QQ) strains) were selected to evaluate their impacts on growth, virulence factors and biofilm formation in Yersinia ruckeri in vitro. No difference was observed among the growth pattern of Y. ruckeri in monoculture and coculture with the QQ strains. To investigate the regulation of virulence factors by quorum sensing in Y. ruckeri, cultures were supplemented with 3oxo-C8-HSL. The results indicated that swimming motility and biofilm formation are positively regulated by QS (p < 0.05), whereas caseinase, phospholipase and haemolysin productions are not influenced by 3oxo-C8-HSL (p > 0.05). The QQs were able to decrease swimming motility and biofilm formation in Y. ruckeri. QQ bacteria were supplemented to trout feed at 108 CFU/g (for 40 days). Their probiotic effect was verified by Y. ruckeri challenge either by immersion or injection in trout. All strains could significantly increase fish survival with Bacillus thuringiensis and Citrobacter gillenii showing the highest and lowest relative percentage survival (RPS) values (respectively, 85% and 38%). Besides, there was no difference between the RPS values by either immersion or injection challenge expect for B. thuringiensis. The putative involvement of the QQ capacity in the protection against Yersinia is discussed.},
}
@article {pmid30013374,
year = {2018},
author = {de Alteriis, E and Maselli, V and Falanga, A and Galdiero, S and Di Lella, FM and Gesuele, R and Guida, M and Galdiero, E},
title = {Efficiency of gold nanoparticles coated with the antimicrobial peptide indolicidin against biofilm formation and development of Candida spp. clinical isolates.},
journal = {Infection and drug resistance},
volume = {11},
number = {},
pages = {915-925},
doi = {10.2147/IDR.S164262},
pmid = {30013374},
issn = {1178-6973},
abstract = {Background: This article examines the use of a novel nano-system, gold nanoparticles coated with indolicidin (AuNPs-indolicidin), against pathogenic Candida albicans biofilms. Candida species cause frequent infections owing to their ability to form biofilms, primarily on implant devices.<br><br>Materials and methods: We used an integrated approach, evaluating the effect of AuNPs-indolicidin on prevention and eradication of Candida biofilms formed in multi-well polystyrene plates, with relative gene expression assays. Four biofilm-associated genes (FG1, HWP1, ALS1 and ALS3, and CDR1 and CDR2) involved in efflux pump were analyzed using reverse transcription polymerase chain reaction.<br><br>Results: Treatment with the nano-complex significantly inhibits the capacity of C. albicans to form biofilms and impairs preformed mature biofilms. Treatment with AuNPs-indolicidin results in an increase in the kinetics of Rhodamine 6G efflux and a reduction in the expression of biofilm-related genes.<br><br>Conclusion: These data provide a chance to develop novel therapies against nosocomially acquired refractory C. albicans biofilms.},
}
@article {pmid30013272,
year = {2018},
author = {Virmani, R and Hasija, Y and Singh, Y},
title = {Effect of Homocysteine on Biofilm Formation by Mycobacteria.},
journal = {Indian journal of microbiology},
volume = {58},
number = {3},
pages = {287-293},
doi = {10.1007/s12088-018-0739-8},
pmid = {30013272},
issn = {0046-8991},
abstract = {Mycobacteria show peculiar aggregated outgrowth like biofilm on the surface of solid or liquid media. Biofilms harbor antibiotic resistant bacteria in a self-produced extracellular matrix that signifies the bacterial fate to sedentary existence. Despite years of research, very little is known about the mechanisms that contribute to biofilm formation. LuxS has been previously known to play a role in biofilm formation in Autoinducer-2 dependent manner. We here show the effect of LuxS product-homocysteine, on the biofilm forming ability of non-tuberculous mycobacteria, Mycobacterium smegmatis and Mycobacterium bovis BCG showing AI-2 independent phenotypic effect of LuxS. Exogenous supplementation of homocysteine in the culture media leads to aberrant cording, pellicle outgrowth, and biofilm formation. Thus, our study contributes to the better understanding of the mechanism of mycobacterial biofilm formation and sheds light on the role of LuxS product homocysteine. In addition, we highlight the contribution of activated methyl cycle in bacterial quorum sensing.},
}
@article {pmid30013112,
year = {2018},
author = {Fleming, D and Rumbaugh, K},
title = {The Consequences of Biofilm Dispersal on the Host.},
journal = {Scientific reports},
volume = {8},
number = {1},
pages = {10738},
doi = {10.1038/s41598-018-29121-2},
pmid = {30013112},
issn = {2045-2322},
support = {R01GM116547//U.S. Department of Health &amp; Human Services | National Institutes of Health (NIH)/ ; R01GM116547//U.S. Department of Health &amp; Human Services | National Institutes of Health (NIH)/ ; W911NF-13-1-0199//DOD | Army Research Office (ARO)/ ; W911NF-13-1-0199//DOD | Army Research Office (ARO)/ ; },
abstract = {Chronic infections are often associated with the presence of a biofilm, a community of microorganisms coexisting within a protective matrix of extracellular polymeric substance. Living within a biofilm can make resident microbes significantly more tolerant to antibiotics in comparison to planktonic, free-floating cells. Thus, agents that can degrade biofilms are being pursued for clinical applications. While biofilm degrading and dispersing agents may represent attractive adjunctive therapies for biofilm-associated chronic infections, very little is known about how the host responds to the sudden dispersal of biofilm cells. In this study, we found that large-scale, in vivo dispersal of motile biofilm bacteria by glycoside hydrolases caused lethal septicemia in the absence of antibiotic therapy in a mouse wound model. However, when administered prudently, biofilm degrading enzymes had the potential to potentiate the efficacy of antibiotics and help resolve biofilm-associated wound infections.},
}
@article {pmid30012773,
year = {2018},
author = {Blanchard, JD and Elias, V and Cipolla, D and Gonda, I and Bermudez, LE},
title = {Effective treatment of the Mycobacterium avium subsp hominissuis and Mycobacterium abscessus sp. infections in macrophages, biofilm and in mice using Liposomal ciprofloxacin.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.00440-18},
pmid = {30012773},
issn = {1098-6596},
abstract = {Non-tuberculosis mycobacteria (NTM) affects an increasing number of individuals worldwide. The infection is more common in patients with chronic lung conditions, and treatment is challenging. Quinolones, such as ciprofloxacin, have been used to treat patients, but the results have not been encouraging. In this report, we evaluate novel formulations of liposome-encapsulated ciprofloxacin (liposomal ciprofloxacin) in vitro and in vivo Efficacy was examined in macrophages, biofilms and in vivo using intranasal instillation mouse models against Mycobacterium avium and Mycobacterium abscessus Liposomal ciprofloxacin was significantly more active than free ciprofloxacin in macrophages and biofilms against both pathogens. When evaluated in vivo, the liposomal ciprofloxacin formulations were associated with significant decreases in bacterial loads in the lung of animals infected with M. avium and M. abscessusIn summary, topical delivery of liposomal ciprofloxacin in the lung at concentrations greater than achieved in the serum can be effective in the treatment of NTM and further evaluation is warranted.},
}
@article {pmid30012484,
year = {2018},
author = {Wu, Y and Ying, Y and Liu, Y and Zhang, H and Huang, J},
title = {Preparation of chitosan/poly vinyl alcohol films and their inhibition of biofilm formation against Pseudomonas aeruginosa PAO1.},
journal = {International journal of biological macromolecules},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijbiomac.2018.07.061},
pmid = {30012484},
issn = {1879-0003},
abstract = {Poly (vinyl alcohol) (PVA) and chitosan (CH)-based blend films were prepared via a simple mixing and casting method. The films were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and ultraviolet-visible spectroscopy (UV-vis). Mechanical properties, thermogravimetric (TG), derivative thermogravimetric (DTG), and the inhibition of biofilm formation against Pseudomonas aeruginosa PAO1 (P. aeruginosa PAO1) of CH/PVA films were investigated. The results indicated that CH and PVA in the blend films interacted by physical crosslinks consisting of intermolecular hydrogen bonds and intermolecular hydrogen bonds with compatibility, and were more thermally-stable than that of PVA. CH addition decreased the tensile strength and the light transmittance. CH60:PVA40 film showed notable activity against adhesion and inhibited biofilm formation of P. aeruginosa PAO1, indicating that CH60:PVA40 film could be applied as an antimicrobial and biofilm inhibiting food packaging material.},
}
@article {pmid30011379,
year = {2018},
author = {Loustau, E and Rols, JL and Leflaive, J and Marcato-Romain, CE and Girbal-Neuhauser, E},
title = {Comparison of extraction methods for the characterization of extracellular polymeric substances from aggregates of three biofilm-forming phototrophic microorganisms.},
journal = {Canadian journal of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1139/cjm-2018-0182},
pmid = {30011379},
issn = {1480-3275},
abstract = {This paper aims to define a robust procedure to extract Extracellular Polymeric Substances (EPS) from aggregates of three benthic phototrophic microorganisms (cyanobacterium Phormidium autumnale, diatom Nitzschia palea and green alga Uronema confervicolum). This study focuses on the extraction efficiency of polysaccharide and protein EPS by using two physical methods (sonication, cation exchange resin) and three chemical methods (Formamide, EDTA, Tween 20) with minimum cell lysis. Cell lysis was evaluated by monitoring chlorophyll a release. Results indicated that sonication or incubation with 0.25 % Tween 20 of the algae aggregates induced high level of cell lysis. A combined extraction approach, with a first dispersing pre-treatment (Ultra-Turrax, 13,500 rpm, 1 min), Formamide addition (0.22 %) and then incubation with Dowex Cation Exchange Resin (50 g per g of biomass), provided the highest amount of extracted EPS (protein as most part), with low cell lysis. Furthermore, extracted EPS were characterised by Size Exclusion Chromatography and the obtained fingerprints revealed similar profiles for the three benthic microorganisms with a majority of low molecular weight polymers (400 to 11,300 Da). However, additional EPS of high (> 600,000 Da) and intermediate (20,000 to 80,000 Da) molecular sizes were specifically detected in the diatom extracts.},
}
@article {pmid30009382,
year = {2018},
author = {Ceccarelli, F and Orrù, G and Pilloni, A and Bartosiewicz, I and Perricone, C and Martino, E and Lucchetti, R and Fais, S and Vomero, M and Olivieri, M and di Franco, M and Priori, R and Riccieri, V and Scrivo, R and Shoenfeld, Y and Alessandri, C and Conti, F and Polimeni, A and Valesini, G},
title = {Porphyromonas gingivalis in the tongue biofilm is associated with the clinical outcome in rheumatoid arthritis patients.},
journal = {Clinical and experimental immunology},
volume = {},
number = {},
pages = {},
doi = {10.1111/cei.13184},
pmid = {30009382},
issn = {1365-2249},
abstract = {OBJECTIVE: Several evidences suggested a link between human microbiome and Rheumatoid Arthritis (RA) development. Porphyromonas gingivalis (P. gingivalis) seems involved in RA initiation and progression, as supported by the high occurrence of periodontitis. In this case-control study, we analyzed tongue P. gingivalis presence and quantification in a large healthy and RA cohort.<br><br>METHODS: We enrolled 143 RA patients (Male/Female 32/111, mean±SD age 57.5±19.8 years, mean±SD disease duration 155.9± 114.7 months); 36 periodontitis patients (M/F 11/25, mean±SD age56±9.9 years, mean±SD disease duration 25.5±20.9 months); 57 patients (M/F 12/45, mean ±SD age 61.4±10.9 years, mean ±SD disease duration 62.3±66.9 months) with knee osteoarthritis or fibromyalgia. All subjects underwent a standard cytologic swab to identify the rate of P. gingivalis/total bacteria by using quantitative real time PCR.<br><br>RESULTS: The prevalence of P. gingivalis resulted similar in RA and periodontitis patients (48.9% versus 52.7%, P=NS). Moreover, the prevalence of this pathogen was significantly higher in RA and PD patients in comparison with CS (P=0.01 and P=0.003, respectively). We found a significant correlation between P. gingivalis rate in total bacteria genomes and DAS28(ESR) (r=0.4, P=0.01). RA patients in remission showed a significantly lower prevalence of P. gingivalis in comparison with non-remission (P=0.02).<br><br>CONCLUSIONS: We demonstrated a significant association between the percentage of P. gingivalis on the total tongue biofilm and RA disease activity (DAS28), suggesting that the oral cavity microbiological status could play a role in the pathogenic mechanisms of inflammation, leading to a more active disease. This article is protected by copyright. All rights reserved.},
}
@article {pmid30009352,
year = {2018},
author = {Shafikova, TN and Omelichkina, YV and Enikeev, AG and Boyarkina, SV and Gvildis, DE and Semenov, AA},
title = {Ortho-Phthalic Acid Esters Suppress the Phytopathogen Capability for Biofilm Formation.},
journal = {Doklady biological sciences : proceedings of the Academy of Sciences of the USSR, Biological sciences sections},
volume = {480},
number = {1},
pages = {107-109},
doi = {10.1134/S0012496618030092},
pmid = {30009352},
issn = {1608-3105},
abstract = {This is the first study demonstrating that ortho-phthalic acid esters, dibutylphthalate (DBP) and di-(2-ethylhexyl)-o-phthalate (DEHP), inhibit the ability to form biofilms of the biotrophic pathogen Clavibacter michiganensis ssp. sepedonicus and Pectobacterium carotovorum ssp. carotovorum necrotroph. Inhibition of biofilm formation depends on the DBP and DEHP concentrations.},
}
@article {pmid30008421,
year = {2018},
author = {Ngabaza, T and Moeno, S and Patel, M},
title = {Anti-acidogenic and anti-biofilm activity of 5,6,8-trihydroxy-7-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one.},
journal = {Microbial pathogenesis},
volume = {123},
number = {},
pages = {149-152},
doi = {10.1016/j.micpath.2018.07.003},
pmid = {30008421},
issn = {1096-1208},
abstract = {OBJECTIVES: Crude extracts of Dodonaea viscosa var. angustifolia (DVA), has shown to have anticariogenic property. However the compound responsible for this activity has not been identified. The aim of this study was to investigate anti-acidogenic and anti-biofilm activity of a flavone 5,6,8-Trihydroxy-7-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one isolated from D. viscosa var. angustifolia (DVA) in cariogenic bacteria Streptococcus mutans.<br><br>METHODS: The crude extract from DVA leaves was fractionated into six fractions (F1-F6) using chromatography. The Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentration (MBC) were determined. The effect of the six fractions on biofilm formation and acid production were investigated. The most active fraction (F5) was further fractionated, purified, identified and elucidated using GC-MS and NMR. The anticariogenic property of this purified compound was established. Results were analyzed using Wilcoxon rank-sum test (Mann-Whitney).<br><br>RESULTS: The MIC and MBC of the fractions (F1-F6) and crude extract ranged from 0.39 to 12.5 mg/ml. F5 showed the lowest MBC. At 0.2 mg/ml, F5 reduced biofilm formation by 93.3% and reduced acid production in S. mutans. Subfraction F5.1 showed higher antimicrobial activity compared to the crude extract and F5. Purified F5.1 was identified as 5,6,8-Trihydroxy-7-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one (TMMC). TMMC inhibited biofilm formation at both 6 h (94% reduction) and 24 h (99% reduction), which was higher compared to the crude extract (87% reduction at 0.78 mg/ml after 6 h). TMMC also exhibited a higher inhibitory effect on acid production compared to the crude extract.<br><br>CONCLUSION: Flavone 5,6,8-Trihydroxy-7-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one derived from DVA has anti-S. mutans, anti-biofilm and anti-acidogenic activity therefore it has a potential for use in the oral cavity to prevent dental caries.},
}
@article {pmid30007730,
year = {2018},
author = {de Oliveira Dembogurski, DS and Silva Trentin, D and Boaretto, AG and Rigo, GV and da Silva, RC and Tasca, T and Macedo, AJ and Carollo, CA and Silva, DB},
title = {Brown propolis-metabolomic innovative approach to determine compounds capable of killing Staphylococcus aureus biofilm and Trichomonas vaginalis.},
journal = {Food research international (Ottawa, Ont.)},
volume = {111},
number = {},
pages = {661-673},
doi = {10.1016/j.foodres.2018.05.033},
pmid = {30007730},
issn = {1873-7145},
abstract = {Propolis, a resin produced by bees, is widely used in industrial products, including food, cosmetics, supplements, and pharmaceuticals. Extracts (ethanolic and hydroethanolic) and fractions, yielded by accelerated solvent extraction methodology, were obtained from different samples of Brazilian brown propolis (BBP). They were evaluated for antioxidant capacity, antibacterial, antibiofilm, and anti-Trichomonas vaginalis activities. The metabolomics profiling was determined by LC-DAD-MS and an innovative application of statistical analyses (univariate and chemometrics) was applied to correlate chemical compounds with biological activities. Eighty-six compounds were identified, including phenylpropanoic acids, flavonoids, chlorogenic acids, and prenylated phenylpropanoic acids. Propolis-fractions killed about 93% of Staphylococcus aureus in biofilm (at concentration of 125 μg/mL), showed activity against T. vaginalis with MIC at 400 μg/mL and significative antioxidant capacity (IC50 2.32-3.80 μg/mL). Propolis extracts and fractions did not show antibacterial and antibiofilm activities against Pseudomonas aeruginosa. The prenylated phenylpropanoic acids positively correlated with both the antibiofilm (S. aureus) and anti-T. vaginalis activities, such as the metabolites artepillin C, drupanin, and baccharin.},
}
@article {pmid30007313,
year = {2018},
author = {Hsieh, ML and Hinton, DM and Waters, CM},
title = {VpsR and cyclic di-GMP together drive transcription initiation to activate biofilm formation in Vibrio cholerae.},
journal = {Nucleic acids research},
volume = {},
number = {},
pages = {},
doi = {10.1093/nar/gky606},
pmid = {30007313},
issn = {1362-4962},
abstract = {The small molecule cyclic di-GMP (c-di-GMP) is known to affect bacterial gene expression in myriad ways. In Vibrio cholerae in vivo, the presence of c-di-GMP together with the response regulator VpsR results in transcription from PvpsL, a promoter of biofilm biosynthesis genes. VpsR shares homology with enhancer binding proteins that activate σ54-RNA polymerase (RNAP), but it lacks conserved residues needed to bind to σ54-RNAP and to hydrolyze adenosine triphosphate, and PvpsL transcription does not require σ54 in vivo. Consequently, the mechanism of this activation has not been clear. Using an in vitro transcription system, we demonstrate activation of PvspL in the presence of VpsR, c-di-GMP and σ70-RNAP. c-di-GMP does not significantly change the affinity of VpsR for PvpsL DNA or the DNase I footprint of VpsR on the DNA, and it is not required for VpsR to dimerize. However, DNase I and KMnO4 footprints reveal that the σ70-RNAP/VpsR/c-di-GMP complex on PvpsL adopts a different conformation from that formed by σ70-RNAP alone, with c-di-GMP or with VpsR. Our results suggest that c-di-GMP is required for VpsR to generate the specific protein-DNA architecture needed for activated transcription, a previously unrecognized role for c-di-GMP in gene expression.},
}
@article {pmid30006320,
year = {2018},
author = {Tan, Y and Cheng, Q and Yang, H and Li, H and Gong, N and Liu, D and Wu, J and Lei, X},
title = {Effects of ALA-PDT on biofilm structure, virulence factor secretion, and QS in Pseudomonas aeruginosa.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2018.07.005},
pmid = {30006320},
issn = {1873-1597},
abstract = {AIM: To investigate the effects of ALA-PDT on biofilm structure, virulence factor secretion, and quorum sensing (QS) in Pseudomonas aeruginosa.<br><br>MATERIALS AND METHODS: We used confocal laser scanning microscopy (CLSM), an XTT assay, scanning electron microscopy (SEM), a virulence factor assay and qRT-PCR in this study.<br><br>RESULTS: The XTT assay showed that ALA-PDT significantly inhibited the growth of planktonic P. aeruginosa. CLSM and SEM showed that ALA-PDT destroyed both bacterial and biofilm structures. The virulence factor assay showed that pyocyanin and elastase secretion were significantly inhibited in the ALA-PDT groups. qRT-PCR assays demonstrated that ALA-PDT significantly reduced the mRNA expression of QS-related genes.<br><br>CONCLUSION: ALA-PDT kills planktonic and viable biofilm-associated P. aeruginosa cells, destroys biofilm structures, reduces virulence factor secretion and affects QS system gene expression.},
}
@article {pmid30006276,
year = {2018},
author = {Biswas, N and Samanta, A and Podder, S and Ghosh, CK and Ghosh, J and Das, M and Mallik, AK and Mukhopadhyay, AK},
title = {Phase pure, high hardness, biocompatible calcium silicates with excellent anti-bacterial and biofilm inhibition efficacies for endodontic and orthopaedic applications.},
journal = {Journal of the mechanical behavior of biomedical materials},
volume = {86},
number = {},
pages = {264-283},
doi = {10.1016/j.jmbbm.2018.06.046},
pmid = {30006276},
issn = {1878-0180},
abstract = {Here we report for the very first time the synthesis of 100% phase pure calcium silicate nanoparticles (CSNPs) of the α-wollastonite phase without using any surfactant or peptizer at the lowest ever reported calcination temperature of 850 °C. Further, the phase purity is confirmed by quantitative phase analysis. The nano-network like microstructure of the CSNPs is characterized by FTIR, Raman, XRD, FESEM, TEM, TGA, DSC etc. techniques to derive the structure property correlations. The performance efficacies of the CSNPs against gram-positive e.g., S. pyogenes and S. aureus (NCIM2127) and gram-negative e.g., E. coli (NCIM2065) bacterial strains are studied. The biocompatibility of the CSNPs is established by using the conventional mouse embryonic osteoblast cell line (MC3T3). In addition, the biofilm inhibition efficacies of two varieties of CSNPs e.g., CSNPs(W) and CSNPs(WC) are investigated. Further, the interconnection between ROS e.g., superoxide (O2.-) and hydroxyl radical (.OH) generation capabilities of CSNPs and their biofilm inhibition efficacies is clearly established for the very first time. Finally, the mechanical responses of the CSNPs at the microstructural length scale are investigated by nanoindentation. The results confirm that the α-wollastonite phases present in CSNPs(W) and CSNPs(WC) possess extraordinarily high nanohardness and Young's moduli values. Therefore, these materials are well suited for orthopaedic and endodontic applications.},
}
@article {pmid30003870,
year = {2018},
author = {Svenningsen, SL},
title = {Small RNA-Based Regulation of Bacterial Quorum Sensing and Biofilm Formation.},
journal = {Microbiology spectrum},
volume = {6},
number = {4},
pages = {},
doi = {10.1128/microbiolspec.RWR-0017-2018},
pmid = {30003870},
issn = {2165-0497},
abstract = {Quorum sensing is a vital property of bacteria that enables community-wide coordination of collective behaviors. A key example of such a behavior is biofilm formation, in which groups of bacteria invest in synthesizing a protective, joint extracellular matrix. Quorum sensing involves the production, release, and subsequent detection of extracellular signaling molecules called autoinducers. The architecture of quorum-sensing signal transduction pathways is highly variable among different species of bacteria, but frequently involves posttranscriptional regulation carried out by small regulatory RNA molecules. This review illustrates the diverse roles small trans-acting regulatory RNAs can play, from constituting a network's core to auxiliary roles in adjusting the rate of autoinducer synthesis, mediating cross talk among different parts of a network, or integrating different regulatory inputs to trigger appropriate changes in gene expression. The emphasis is on describing how the study of small RNA-based regulation in quorum sensing and biofilm formation has uncovered new general properties or expanded our understanding of bacterial riboregulation.},
}
@article {pmid30002533,
year = {2018},
author = {},
title = {Help prevent biofilm build-up.},
journal = {British dental journal},
volume = {225},
number = {1},
pages = {86},
doi = {10.1038/sj.bdj.2018.580},
pmid = {30002533},
issn = {1476-5373},
}
@article {pmid30001126,
year = {2018},
author = {Lai, CY and Dong, QY and Rittmann, BE and Zhao, HP},
title = {Bio-reduction of Antimonate by Anaerobic Methane Oxidation in a Membrane Biofilm Batch Reactor.},
journal = {Environmental science &amp; technology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.est.8b02035},
pmid = {30001126},
issn = {1520-5851},
abstract = {Employing a special anaerobic membrane biofilm batch reactor (MBBR), we demonstrated antimonate (Sb(V)) reduction using methane (CH4) as the sole electron donor. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman and photoluminescence (PL) spectra identified that Sb2O3 microcrystals were the main reduced products. The Sb(V) reduction rate increased continually over the 111-day experiment, which supports the enrichment of the microorganisms responsible for Sb(V) reduction to Sb(III). Copy numbers of the mcrA gene and archaeal and bacterial 16 S rRNA genes increased in parallel. Clone library and Illumina sequencing of 16S rRNA gene demonstrated that Methanosarcina became the dominant archaea in the biofilm, suggesting that Methanosarcina might play an important role in Sb(V) reduction in the CH4-based MBBR.},
}
@article {pmid29998876,
year = {2018},
author = {Zhao, J and Cheng, W and He, X and Liu, Y and Li, J and Sun, J and Li, J and Wang, F and Gao, Y},
title = {Association of furanone C-30 with biofilm formation &amp; antibiotic resistance in Pseudomonas aeruginosa.},
journal = {The Indian journal of medical research},
volume = {147},
number = {4},
pages = {400-406},
doi = {10.4103/ijmr.IJMR_2010_16},
pmid = {29998876},
issn = {0971-5916},
abstract = {Background &amp; objectives: Pseudomonas aeruginosa is an opportunistic pathogen that can cause nosocomial bloodstream infections in humans. This study was aimed to explore the association of furanone C-30 with biofilm formation, quorum sensing (QS) system and antibiotic resistance in P. aeruginosa.<br><br>Methods: An in vitro model of P. aeruginosa bacterial biofilm was established using the standard P. aeruginosa strain (PAO-1). After treatment with 2.5 and 5 μg/ml of furanone C-30, the change of biofilm morphology of PAO-1 was observed, and the expression levels of QS-regulated virulence genes (lasB, rhlA and phzA2), QS receptor genes (lasR, rhlR and pqsR) as well as QS signal molecule synthase genes (lasI, rhlI, pqsE and pqsH) were determined. Besides, the AmpC expression was quantified in planktonic and mature biofilm induced by antibiotics.<br><br>Results: Furanone C-30 treatment significantly inhibited biofilm formation in a dose-dependent manner. With the increase of furanone C-30 concentration, the expression levels of lasB, rhlA, phzA2, pqsR, lasI, rhlI pqsE and pqsH significantly decreased in mature biofilm bacteria while the expression levels of lasR and rhlR markedly increased. The AmpC expression was significantly decreased in both planktonic and biofilm bacteria induced by imipenem and ceftazidime.<br><br>Furanone C-30 may inhibit biofilm formation and antibiotic resistance in P. aeruginosa through regulating QS genes. The inhibitory effect of furanone C-30 on las system appeared to be stronger than that on rhl system. Further studies need to be done with different strains of P. aeruginosa to confirm our findings.},
}
@article {pmid29998558,
year = {2018},
author = {Veach, AM and Griffiths, NA},
title = {Testing the light:nutrient hypothesis: Insights into biofilm structure and function using metatranscriptomics.},
journal = {Molecular ecology},
volume = {27},
number = {14},
pages = {2909-2912},
doi = {10.1111/mec.14733},
pmid = {29998558},
issn = {1365-294X},
abstract = {Aquatic biofilms are hotspots of biogeochemical activity due to concentrated microbial biomass (Battin, Kaplan, Newbold, &amp; Hansen,). However, biofilms are often considered a single entity when their role in biogeochemical transformations is assessed, even though these biofilms harbour functionally diverse microbial communities (Battin, Besemer, Bengtsson, Romani, &amp; Packmann, ; Veach, Stegen, Brown, Dodds, &amp; Jumpponen,). Often overlooked are the biotic interactions among biofilm components that can affect ecosystem-scale processes such as primary production and nutrient cycling. These interactions are likely to be especially important under resource limitation. Light is a primary resource mediating algal photosynthesis and both phototrophic and heterotrophic production due to bacterial reliance on C-rich algal exudates (Cole,). However, current understanding of function-structure linkages in streams has yet to unravel the relative degree of these microbial feedbacks under resource availability gradients. In this issue of Molecular Ecology, Bengtsson, Wagner, Schwab, Urich, and Battin () studied stream biofilm responses to light availability to understand its impact across three domains of life. By integrating biogeochemical rate estimation and metatranscriptomics within a microcosm experiment, they were able to link primary production and nutrient uptake rates to algal and bacterial metabolic processes and specify what taxa contributed to gene expression. Under low light, diatoms and cyanobacteria upregulated photosynthetic machinery and diatom-specific chloroplast rRNA suggesting heightened transcriptional activity under light limitation to maintain phototrophic energy demands. Under high light, heterotrophic bacteria upregulated mRNAs related to phosphorous (P) metabolism while biofilm P uptake increased indicating high bacterial-specific P demand when algal biomass was high. Together, these results indicate that biogeochemical function is mediated by complex microbial interactions across trophic levels.},
}
@article {pmid29997746,
year = {2018},
author = {Goudarzi, M and Mobarez, AM and Najar-Peerayeh, S and Mirzaee, M},
title = {Prevalence of biofilm formation and vancomycin-resistant genes among Enterococcus faecium isolated from clinical and environmental specimens in Lorestan hospitals.},
journal = {Iranian journal of microbiology},
volume = {10},
number = {2},
pages = {74-81},
pmid = {29997746},
issn = {2008-3289},
abstract = {Background and Objectives: The antibiotic resistance among Enterococcus faecium strains has increased worldwide. Additionally, biofilm-forming isolates of E. faecium play an important role in human infections. This study was conducted to investigate the prevalence of virulence and antibiotic resistance genes between biofilm-producing and non-biofilm-producing E. faecium strains.<br><br>Materials and Methods: In this study, 228 E. faecium isolates from clinical and environmental specimens were obtained from different wards of hospitals in Lorestan province (Iran). Then, the pattern of antibiotic resistance and minimum inhibitory concentration (MIC) against β-lactams, glycopeptides, aminoglycosides and other common antibiotics was investigated using disk diffusion and agar dilution methods. Biofilm formation was investigated using polystyrene microtiter plates. PCR assay was conducted for antibiotic resistance and biofilm related genes. Pulse field gel electrophoresis (PFGE) was used to determine the clonal spread of isolates.<br><br>Results: Most of isolates (78%) were resistant to penicillin, but all were susceptible to linezolid and tigecycline. The biofilm-producing isolates were more resistant to β-lactams, glycopeptides and aminoglycosides compared to non-biofilm-producing strains. In biofilm-producing isolates, pilA, pilB, efaAfm and esp were the dominant virulence genes and vanA and pbp5 genes were the dominant resistant genes. PFGE analysis exhibited a similar pattern between the clinical and environmental isolates, suggesting the presence of a common origin of the infection by E. faecium.<br><br>Conclusion: The results of the antibiotic resistance, biofilm assay, and PFGE analysis suggest that there is a common clone of persistent and biofilm-producing strains of E. faecium, which could rapidly disseminate in patients and the environment.},
}
@article {pmid29997606,
year = {2018},
author = {Miyaue, S and Suzuki, E and Komiyama, Y and Kondo, Y and Morikawa, M and Maeda, S},
title = {Bacterial Memory of Persisters: Bacterial Persister Cells Can Retain Their Phenotype for Days or Weeks After Withdrawal From Colony-Biofilm Culture.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1396},
doi = {10.3389/fmicb.2018.01396},
pmid = {29997606},
issn = {1664-302X},
abstract = {Persister cells, or persisters, are a specific subpopulation of bacterial cells that have acquired temporary antibiotic-resistant phenotypes. In this study, we showed that Escherichia coli produces many more persister cells in colony-biofilm culture than in the usual liquid culture and that these persisters can be maintained in higher numbers than those from liquid culture for up to 4 weeks at 37°C in a fresh, nutrient-rich, antibiotic-containing medium, even after complete withdrawal from the colony-biofilm culture. This suggests the presence of a long-retention effect, or &quot;memory effect&quot;, in the persister cell state of E. coli cells. We also discovered that such increases in persisters during colony-biofilm culture and their memory effects are common, to a greater or lesser degree, in other bacterial species. This is true not only for gram-negative bacteria (Acinetobacter and Salmonella) but also for gram-positive bacteria (Staphylococcus and Bacillus). This is the first report to suggest the presence of a common memory mechanism for the persister cell state, which is inscribed during colony-biofilm culture, in a wide variety of bacteria.},
}
@article {pmid29997584,
year = {2018},
author = {Somorin, YM and Vollmerhausen, T and Waters, N and Pritchard, L and Abram, F and Brennan, F and O'Byrne, C},
title = {Absence of Curli in Soil-Persistent Escherichia coli Is Mediated by a C-di-GMP Signaling Defect and Suggests Evidence of Biofilm-Independent Niche Specialization.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1340},
doi = {10.3389/fmicb.2018.01340},
pmid = {29997584},
issn = {1664-302X},
abstract = {Escherichia coli is commonly viewed as a gastrointestinal commensal or pathogen although an increasing body of evidence suggests that it can persist in non-host environments as well. Curli are a major component of biofilm in many enteric bacteria including E. coli and are important for adherence to different biotic and abiotic surfaces. In this study we investigated curli production in a unique collection of soil-persistent E. coli isolates and examined the role of curli formation in environmental persistence. Although most soil-persistent E. coli were curli-positive, 10% of isolates were curli-negative (17 out of 170). Curli-producing E. coli (COB583, COB585, and BW25113) displayed significantly more attachment to quartz sand than the curli-negative strains. Long-term soil survival experiments indicated that curli production was not required for long-term survival in live soil (over 110 days), as a curli-negative mutant BW25113ΔcsgB had similar survival compared to wild type BW25113. Mutations in two genes associated with c-di-GMP metabolism, dgcE and pdeR, correlated with loss of curli in eight soil-persistent strains, although this did not significantly impair their survival in soil compared to curli-positive strains. Overall, the data indicate that curli-deficient and biofilm-defective strains, that also have a defect in attachment to quartz sand, are able to reside in soil for long periods of time thus pointing to the possibility that niches may exist in the soil that can support long-term survival independently of biofilm formation.},
}
@article {pmid29997579,
year = {2018},
author = {Hu, X and Huang, YY and Wang, Y and Wang, X and Hamblin, MR},
title = {Antimicrobial Photodynamic Therapy to Control Clinically Relevant Biofilm Infections.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {1299},
doi = {10.3389/fmicb.2018.01299},
pmid = {29997579},
issn = {1664-302X},
abstract = {Biofilm describes a microbially-derived sessile community in which microbial cells are firmly attached to the substratum and embedded in extracellular polymeric matrix. Microbial biofilms account for up to 80% of all bacterial and fungal infections in humans. Biofilm-associated pathogens are particularly resistant to antibiotic treatment, and thus novel antibiofilm approaches needed to be developed. Antimicrobial Photodynamic therapy (aPDT) had been recently proposed to combat clinically relevant biofilms such as dental biofilms, ventilator associated pneumonia, chronic wound infections, oral candidiasis, and chronic rhinosinusitis. aPDT uses non-toxic dyes called photosensitizers (PS), which can be excited by harmless visible light to produce reactive oxygen species (ROS). aPDT is a multi-stage process including topical PS administration, light irradiation, and interaction of the excited state with ambient oxygen. Numerous in vitro and in vivo aPDT studies have demonstrated biofilm-eradication or substantial reduction. ROS are produced upon photo-activation and attack adjacent targets, including proteins, lipids, and nucleic acids present within the biofilm matrix, on the cell surface and inside the microbial cells. Damage to non-specific targets leads to the destruction of both planktonic cells and biofilms. The review aims to summarize the progress of aPDT in destroying biofilms and the mechanisms mediated by ROS. Finally, a brief section provides suggestions for future research.},
}
@article {pmid29997121,
year = {2018},
author = {Kean, R and Delaney, C and Sherry, L and Borman, A and Johnson, EM and Richardson, MD and Rautemaa-Richardson, R and Williams, C and Ramage, G},
title = {Transcriptome Assembly and Profiling of Candida auris Reveals Novel Insights into Biofilm-Mediated Resistance.},
journal = {mSphere},
volume = {3},
number = {4},
pages = {},
doi = {10.1128/mSphere.00334-18},
pmid = {29997121},
issn = {2379-5042},
abstract = {Candida auris has emerged as a significant global nosocomial pathogen. This is primarily due to its antifungal resistance profile but also its capacity to form adherent biofilm communities on a range of clinically important substrates. While we have a comprehensive understanding of how other Candida species resist and respond to antifungal challenge within the sessile phenotype, our current understanding of C. auris biofilm-mediated resistance is lacking. In this study, we are the first to perform transcriptomic analysis of temporally developing C. auris biofilms, which were shown to exhibit phase- and antifungal class-dependent resistance profiles. A de novo transcriptome assembly was performed, where sequenced sample reads were assembled into an ~11.5-Mb transcriptome consisting of 5,848 genes. Differential expression (DE) analysis demonstrated that 791 and 464 genes were upregulated in biofilm formation and planktonic cells, respectively, with a minimum 2-fold change. Adhesin-related glycosylphosphatidylinositol (GPI)-anchored cell wall genes were upregulated at all time points of biofilm formation. As the biofilm developed into intermediate and mature stages, a number of genes encoding efflux pumps were upregulated, including ATP-binding cassette (ABC) and major facilitator superfamily (MFS) transporters. When we assessed efflux pump activity biochemically, biofilm efflux was greater than that of planktonic cells at 12 and 24 h. When these were inhibited, fluconazole sensitivity was enhanced 4- to 16-fold. This study demonstrates the importance of efflux-mediated resistance within complex C. auris communities and may explain the resistance of C. auris to a range of antimicrobial agents within the hospital environment.IMPORTANCE Fungal infections represent an important cause of human morbidity and mortality, particularly if the fungi adhere to and grow on both biological and inanimate surfaces as communities of cells (biofilms). Recently, a previously unrecognized yeast, Candida auris, has emerged globally that has led to widespread concern due to the difficulty in treating it with existing antifungal agents. Alarmingly, it is also able to grow as a biofilm that is highly resistant to antifungal agents, yet we are unclear about how it does this. Here, we used a molecular approach to investigate the genes that are important in causing the cells to be resistant within the biofilm. The work provides significant insights into the importance of efflux pumps, which actively pump out toxic antifungal drugs and therefore enhance fungal survival within a variety of harsh environments.},
}
@article {pmid29995593,
year = {2018},
author = {Gou, Y and Yang, J and Fang, F and Guo, J and Ma, H},
title = {Feasibility of using a novel algal-bacterial biofilm reactor for efficient domestic wastewater treatment.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-11},
doi = {10.1080/09593330.2018.1499812},
pmid = {29995593},
issn = {0959-3330},
abstract = {Current algal-bacterial consortia require high hydraulic retention times (HRTs, 2-10 days) to efficiently remove pollutants from domestic wastewaters. A novel algal-bacterial biofilm reactor was developed for a much lower HRT. The results showed that an HRT of 12 h ensured 90% removal of organic matter and ammonium, and phosphate removal was approximately 30%. Decreasing the HRT to 8 h significantly deteriorated the reactor's pollutant removal efficiencies and increasing the HRT to 24 h did not improve these efficiencies. Illumination, which was light source for algae, was provided by a LED light. Activity tests showed that organic matter and ammonium removal rates resulting from illumination were 70% and 50%, respectively, of the rates when dissolved oxygen concentration was maintained at 2 mg/L. Chemical oxygen demand (COD) removal rates resulted from illumination and aeration were 18.63 and 25.38 mg COD/L.h, respectively. The phosphate removal rate was 0.26 and 0.43 mg/L.h when illumination and aeration were applied, respectively. The ammonium removal rates were approximately 10,390 and 5000 mg [Formula: see text] when the reactor was aerated or illuminated, respectively. These two rates were significantly higher than reported nitrification rates. Moreover, the percentage of Oscillatoria sp. increased from below 10% to over 90% under the applied organic load and temperature, while the percentage of fast growing algae, Chlorella, chroococcus sp and Scenedesmus sp., decreased from over 90% to below 10%. These results showed that an algal-bacterial biofilm reactor with a low reactor footprint was developed.},
}
@article {pmid29995389,
year = {2018},
author = {Shogren, A and Tank, JL and Egan, SP and August, O and Rosi, EJ and Hanrahan, BR and Renshaw, MA and Gantz, CA and Bolster, D},
title = {Water flow and biofilm cover influence environmental DNA (eDNA) detection in recirculating streams.},
journal = {Environmental science &amp; technology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.est.8b01822},
pmid = {29995389},
issn = {1520-5851},
abstract = {The application of environmental DNA (eDNA) to infer species presence in aquatic ecosystems has become an invaluable tool for both the ecology and management of aquatic ecosystems. However, we are only beginning to understand how environmental conditions influence eDNA detection and persistence in freshwaters. Here, we examined the degradation dynamics of fish eDNA using an experimental array of recirculating streams using a novel &quot;nested&quot; primer assay to estimate degradation among eDNA fragment sizes. To assess how biophysical conditions influence eDNA persistence, we introduced eDNA into streams with a range of water velocities (0.1-0.8 m s-1) and substrate biofilm coverage (0-100%), and monitored eDNA concentrations over time (~10 d). We compared degradation rate coefficients across cases using biphasic exponential decay models, suggesting that some eDNA material is labile and degrades quickly, while the remaining eDNA material may be more resistant to decay. We found that the presence of biofilm, regardless of flow velocity, significantly increased initial decay rates relative to previous studies conducted in non-flowing microcosms, suggesting important differences in detection and persistence in lentic vs. lotic systems. Lastly, by using a nested primer assay that targeted differe