@article {pmid32659425,
year = {2020},
author = {Xing, Y and Luo, X and Liu, S and Wan, W and Huang, Q and Chen, W},
title = {Synergistic effect of biofilm growth and cadmium adsorption via compositional changes of extracellular matrix in montmorillonite system.},
journal = {Bioresource technology},
volume = {315},
number = {},
pages = {123742},
doi = {10.1016/j.biortech.2020.123742},
pmid = {32659425},
issn = {1873-2976},
abstract = {The interaction of bacterial biofilm and clay minerals provides great potential for heavy metal remediation in contaminated soil, yet, little is known about how heavy metal, clay minerals and their combinations affect the bacterial biofilm performance and heavy metal adsorption. In this study, the response of biofilm development as well as Cd2+ adsorption in the presence of Cd2+ and montmorillonite has been deciphered. Low concentrations of Cd2+ and montmorillonite or their combinations enhanced biofilm formation by increasing polysaccharides proportion in the biofilm matrix, and the maximum adsorption capacity of Cd2+ by biofilm was increased by 1.5 times. Furthermore, the immobilization of Cd2+ by soil was significantly improved when S14-biofilm was introduced. Such results could gain deeper insight into bacterial survival tactics in the complex systems which makes major contribution to microbial remediation of heavy metal polluted environments.},
}
@article {pmid32658320,
year = {2020},
author = {Li, M and Matouš, K and Nerenberg, R},
title = {Predicting biofilm deformation with a viscoelastic phase field model: modeling and experimental studies.},
journal = {Biotechnology and bioengineering},
volume = {},
number = {},
pages = {},
doi = {10.1002/bit.27491},
pmid = {32658320},
issn = {1097-0290},
abstract = {Biofilms commonly develop in flowing aqueous environments, where the flow causes the biofilm to deform. Because biofilm deformation affects the flow regime, and because biofilms behave as complex heterogeneous viscoelastic materials, few models are able to predict biofilm deformation. In this study, a phase field continuum model coupled with the Oldroyd-B constitutive equation was developed and used to simulate biofilm deformation. The accuracy of the model was evaluated using two types of biofilms: a synthetic biofilm, made from alginate mixed with bacterial cells, and a Pseudomonas aeruginosa biofilm. Shear rheometry was used to experimentally determine the mechanical parameters for each biofilm, as inputs for the model. Biofilm deformation under fluid flow was monitored experimentally using optical coherence tomography. The comparison between the experimental and modeling geometries, for selected horizontal cross sections, after fluid-driven deformation was good. The relative errors ranged from 3.2% to 21.1% for the synthetic biofilm and from 9.1% to 11.1% for the P. aeruginosa biofilm. This is the first demonstration of the effectiveness of a viscoelastic phase field biofilm model. This model provides an important tool for predicting biofilm viscoelastic deformation. It also can benefit the design and control of biofilms in engineering systems. This article is protected by copyright. All rights reserved.},
}
@article {pmid32658271,
year = {2020},
author = {Rattanaphan, P and Mittraparp-Arthorn, P and Srinoun, K and Vuddhakul, V and Tansila, N},
title = {Indole signaling decreases biofilm formation and related virulence of Listeria monocytogenes.},
journal = {FEMS microbiology letters},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsle/fnaa116},
pmid = {32658271},
issn = {1574-6968},
abstract = {Bacterial communication system known as quorum-sensing (QS) is a pivotal system for bacterial survival, adaptation and pathogenesis. Members in the multicellular community may synthesize or acquire a signaling molecule in order to elicit downstream cellular processes. Roles of indole and derivatives, a new class of quorum-sensing signal molecules, in various bacterial physiologies and virulence have been reported recently. Indole is normally found in mammal gastrointestinal tract as a metabolite of tryptophan metabolism by microbiota. Therefore, interspecies connection via indole signaling among commensal bacteria and enteric pathogens could be anticipated. Effects of indole exposure on the virulence of Listeria monocytogenes were investigated by phenotypic and molecular approaches. Results demonstrated that synthetic indole and indole-rich conditioned medium significantly diminished biofilm formation and related virulence of L. monocytogenes including motility, cell aggregation and exopolysaccharide (EPS) production. Transcript levels of virulence-associated (pssE, dltA, flaA, fliI, motB, agrA and hly) and regulatory-genes (codY, sigB, prfA and gmaR) were substantially down-regulated in indole-treated cells. Only mogR gene encoding for a repressor of motility genes was up-regulated after indole exposure. Our findings raise the possibility that L. monocytogenes may acquire indole signaling from gut microbiota for resource-effective adaptation upon transition to new environment.},
}
@article {pmid32656058,
year = {2020},
author = {Al-Joufi, FA and Aljarallah, KM and Hagras, SA and Al Hosiny, IM and Salem-Bekhit, MM and Youssof, AME and Shakeel, F},
title = {Microbial spectrum, antibiotic susceptibility profile, and biofilm formation of diabetic foot infections (2014-18): a retrospective multicenter analysis.},
journal = {3 Biotech},
volume = {10},
number = {7},
pages = {325},
doi = {10.1007/s13205-020-02318-x},
pmid = {32656058},
issn = {2190-572X},
abstract = {This study identifies the risk factors, microbiological properties, antimicrobial susceptibility patterns, mortality, and clinical complications associated with organisms causing diabetic foot infections (DFIs) with or without antibiotic treatment using data from a retrospective multicenter surveillance. Specimens collected from different hospitals were cultured and the extended-spectrum β-lactamase (ESBL) excretion was estimated. The antibacterial susceptibility pattern and biofilm formation were completed along with the recommended standard methods. Overall, 792 diabetic foot patients (DFPs) were enrolled and a total of 1803 causative organisms were isolated. Polymicrobial infection was identified in 48.5% of the patients. The isolated Gram-positive pathogens (46.7%) were higher than Gram-negative (38.6%) or anaerobes (7.9%). The predominant pathogens were S. aureus (22.2%), methicillin-resistant S. aureus (7.7%), Enterococcus spp. (12.8%), Pseudomonas aeruginosa (9.4%), E. coli (7.9%), Klebsiella spp. (7.5%), Proteus mirabilis (8.9%), coagulase negative staphylococci (CoNS) (6.6%), anaerobic organisms (5.9%), and fungi (2.3%). Vancomycin and clindamycin exhibited no activity against Gram-positive bacteria. However, meropenem and imipenem displayed high activity against the Gram-negative isolates. Out of the 765 tested strains, 251 showed moderate (15.8%) to high (34%) level biofilm-producing phenotype. DFIs were widespread among the diabetic patients with different microbial etiology and the major organisms were aerobic organisms. Our findings may provide an insight into the development of appropriate therapeutic strategies for the management of DFIs.},
}
@article {pmid32655644,
year = {2020},
author = {Amzil, K and Hamadi, F and Latrache, H and Mimouni, R and Abou Oualid, H and Azelmad, K and Saidi, A and Elboulani, A and Mabrouki, M},
title = {Pseudomonas aeruginosa Biofilm Removal from Two Kinds of Granite Commonly Found in Catering Kitchen.},
journal = {International journal of microbiology},
volume = {2020},
number = {},
pages = {4313908},
doi = {10.1155/2020/4313908},
pmid = {32655644},
issn = {1687-918X},
abstract = {The biofilm formation on the surfaces which are in direct contact with food products might lead to their contamination and, consequently, present serious health problems for the consumers. The goals of the present work were to study P. aeruginosa biofilm formation on two granites and to investigate the efficiency of sodium hypochlorite (NaCLO) against the same biofilm formed on these substrata using the plate count method (PCM) and epifluorescence microscopy (EP). More biofilm cells adhered to Rosa Porrino than Gris Pinhel, and the PCM method indicated that NaCLO was efficient against the biofilm installed on the Gris Pinhel at the concentration of 1.5% after 15 min of treatment, while it was not efficient against the one installed on the Rosa Porrino. By contrast, the EP showed that the biofilm persists on two granites after NaCLO treatment, at different concentrations and contact times. In addition, the surface properties of granites such as mineral composition, roughness, and physicochemical properties were determined by X-ray diffraction (XRD), scanning electron microscopy coupled with electron diffraction spectroscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared (FTIR), atomic force microscopy (AFM), and contact angle measurement (CAM), respectively. The results revealed that Gris Pinhel is hydrophilic with a high roughness value and Rosa Porrino is hydrophobic with low roughness, while both of them contain the quartz, feldspar, and mica as the main dominant compositions.},
}
@article {pmid32655511,
year = {2020},
author = {Mohanta, YK and Biswas, K and Jena, SK and Hashem, A and Abd Allah, EF and Mohanta, TK},
title = {Anti-biofilm and Antibacterial Activities of Silver Nanoparticles Synthesized by the Reducing Activity of Phytoconstituents Present in the Indian Medicinal Plants.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {1143},
doi = {10.3389/fmicb.2020.01143},
pmid = {32655511},
issn = {1664-302X},
abstract = {Biofilm forming from a variety of microbial pathogens can pose a serious health hazard that is difficult to combat. Nanotechnology, however, represents a new approach to fighting and eradicating biofilm-forming microorganisms. In the present study, the sustainable synthesis and characterization of biocompatible silver nanoparticles (AgNPs) from leaf extracts of Semecarpus anacardium, Glochidion lanceolarium, and Bridelia retusa was explored. Continuous synthesis was observed in a UV-vis spectroscopic analysis and the participating phytoconstituents, flavonoids, phenolic compounds, phytosterols, and glycosides, were characterized by Attenuated total reflectance-Fourier transform infrared spectroscopy. The size and surface charge of the particles were also measured by dynamic light scattering spectroscopy. Scanning electron microscopy study was employed to examine the morphology of the nanoparticles. The spectroscopic and microscopic study confirmed the successful synthesis of AgNPs by plant extracts acting as strong reducing agents. The synthesized AgNPs were screened for antibacterial and anti-biofilm activity against human pathogens Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus. Results of the study demonstrate the potential of phyto-synthesized AgNPs to act as anti-biofilm agents and for other biomedical applications.},
}
@article {pmid32654773,
year = {2020},
author = {Tang, C and Chen, J and Zhang, L and Zhang, R and Zhang, S and Ye, S and Zhao, Z and Yang, D},
title = {Exploring the antibacterial mechanism of essential oils by membrane permeability, apoptosis and biofilm formation combination with proteomics analysis against methicillin-resistant staphylococcus aureus.},
journal = {International journal of medical microbiology : IJMM},
volume = {310},
number = {5},
pages = {151435},
doi = {10.1016/j.ijmm.2020.151435},
pmid = {32654773},
issn = {1618-0607},
abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important causes of food poisoning and infectious diseases worldwide, it can produce a large number of virulence factors, enhance the colonization ability of the host so that it can quickly colonize and spread on the surface of the objects. Essential oil (EO) is one of the natural products with antimicrobial properties, can be used as an important source of antibacterial agent discovery, and has a broad development prospect. However, the unclear mechanisms of antibacterial action have become an obstacle to its further development and use. Hence, the objective of the present study was to reveal the antibacterial mechanism of EO from Amomum villosum Lour (A villosum Lour) against MRSA using label-free quantitative proteomics, investigate the effect of EO on the bacterial proteome, enzymatic activities and leakage of bacterial intracellular biomacromolecule. Proteomic analysis of MRSA in the presence of EO found that a total of 144 differential expressed proteins (DEPs) between the control and treatment group, in which 42 proteins were distinctly up-regulated and 102 proteins were down-regulated. Besides, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, determination of cell membrane permeability and apoptosis, scanning electron microscopy (SEM) observations, bacterial surface hydrophobicity, and biofilm formation measurement were performed. Collectively, the above results indicated that the cell membrane damage by EO leads to the loss of membrane integrity and causes leakage of intracellular macromolecular substances, inhibition of protein, and biofilm synthesis. These findings manifested that EO exerts antibacterial effect by multiple avenues and expands our understanding of the antibacterial mechanism, it has potential application value in food preservative and pharmaceutical industries.},
}
@article {pmid32654271,
year = {2020},
author = {Christensen, DG and Marsden, AE and Hodge-Hanson, K and Essock-Burns, T and Visick, KL},
title = {LapG mediates biofilm dispersal in Vibrio fischeri by controlling maintenance of the VCBS-containing adhesin LapV.},
journal = {Molecular microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mmi.14573},
pmid = {32654271},
issn = {1365-2958},
abstract = {Efficient symbiotic colonization of the squid Euprymna scolopes by the bacterium Vibrio fischeri depends on bacterial biofilm formation on the surface of the squid's light organ. Subsequently, the bacteria disperse from the biofilm via an unknown mechanism and enter through pores to reach interior colonization sites. Here, we identify a homolog of Pseudomonas fluorescens LapG as a dispersal factor that promotes cleavage of a biofilm-promoting adhesin, LapV. Overproduction of LapG inhibited biofilm formation and, unlike the wild-type parent, a ΔlapG mutant formed biofilms in vitro. Although V. fischeri encodes two putative large adhesins, LapI (near lapG on chromosome II) and LapV (on chromosome I), only the latter contributed to biofilm formation. Consistent with the Pseudomonas Lap system model, our data support a role for the predicted c-di-GMP-binding protein LapD in inhibiting LapG-dependent dispersal. Furthermore, we identified a phosphodiesterase, PdeV, whose loss promotes biofilm formation similar to that of the ΔlapG mutant and dependent on both LapD and LapV. Finally, we found a minor defect for a ΔlapD mutant in initiating squid colonization, indicating a role for the Lap system in a relevant environmental niche. Together, these data reveal new factors and provide important insights into biofilm dispersal by V. fischeri.},
}
@article {pmid32654171,
year = {2020},
author = {Lucero-Mejía, JE and Romero-Gómez, SJ and Hernández-Iturriaga, M},
title = {A new classification criterion for the biofilm formation index: A study of the biofilm dynamics of pathogenic Vibrio species isolated from seafood and food contact surfaces.},
journal = {Journal of food science},
volume = {},
number = {},
pages = {},
doi = {10.1111/1750-3841.15325},
pmid = {32654171},
issn = {1750-3841},
abstract = {The bacterial biofilm formation index (BFI) is measured by a microtiter plate assay, and it is typically performed at 72 hr. However, the dynamics of biopolymer formation change during this incubation period. The aims of this study were to follow the biofilm formation dynamics of Vibrio strains isolated from samples of seafood and food contact surfaces (FCS) and to propose a new BFI classification criterion. Samples from seafood (136) and FCS (14) were collected from retail markets in Queretaro, Mexico. The presence of Vibrio spp. was determined, the strains were isolated, and the six major pathogenic species (V. cholerae, V. alginolyticus, V. fluvialis, V. parahaemolyticus, V. vulnificus, V. mimicus) were identified by PCR. The BFI of the isolates was determined by the microtiter plate method. Fifty-one strains were isolated and identified as V. alginolytivcus (25), V. vulnificus (12), V. cholerae (7), V. parahaemolyticus (6), and V. mimicus (1). A quantitative classification criterion of biofilm formation was proposed based on the following factors: BFI dynamics (no formation, continuous increase, and increase followed by decrease), time of maximum BFI (early: 24 hr; late: 48 to 72 hr), and degree of BFI (none, weak, moderate, and strong). A numerical value was assigned to each factor to correlate the resulting BFI profile with a risk level. Thirteen BFI profiles were observed, having risk level values from 0 to 10. Vibrio alginolyticus, V. cholerae, and V. vulnificus showed the highest BFI profile diversities, which included the riskiest profiles. The proposed BFI criterion describes the dynamics of bacterial biopolymer formation and associates them with the possible risk implications. PRACTICAL APPLICATION: In food processing environments, the presence of bacterial biofilms that could include foodborne pathogens might favor cross-contamination due to direct contact or biofilm dispersal into food products. The new quantitative classification criterion for biofilm formation considers their production dynamics over time, the biofilm quantity, and the level of biofilm dispersal. These characteristics are represented by a numerical value that reflects the level of risk associated with the presence of a biofilm-producing strain on a food contact surface.},
}
@article {pmid32654154,
year = {2020},
author = {W, S and Liu, Y and Lei, and Zhang, H},
title = {Nanographene oxides carrying antisense walR RNA regulates the Enterococcus faecalis biofilm formation and its susceptibility to chlorhexidine.},
journal = {Letters in applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/lam.13354},
pmid = {32654154},
issn = {1472-765X},
abstract = {Enterococcus faecalis (E. faecalis) is the dominant pathogen for persistent periapical periodontitis. The chlorhexidine (CHX) is used as conversional irrigation agents during endodontic root canal therapy. It was reported that the antisense walR RNA (ASwalR) suppressed the biofilm organization. The aim of this study was to investigate the antimicrobial effects of novel graphene oxide (GO)-polyethylenimine (PEI)-based antisense walR (ASwalR) on the inhibition of E. faecalis biofilm and its susceptibility to chlorhexidine. The recombinant ASwalR plasmids were modified with a gene encoding enhanced green fluorescent protein (ASwalR-eGFP) as a reporter gene so that the transformation efficiency could be evaluated by the fluorescence intensity. The GO-PEI-based ASwalR vector transformation strategy was developed to be transformed into E. faecalis and to over-produce ASwalR in biofilms. Colony-Forming units (CFU) and confocal laser scanning microscopy (CLSM) were used to investigate whether the antibacterial properties of antisense walR interference strategy sensitize E. faecalis biofilm to the CHX. The results indicated that overexpression of ASwalR by GO-PEI-based transformation strategy could inhibit biofilm formation, decrease the EPS synthesis, and increase the susceptibility of E. faecalis biofilms to CHX. Our reports demonstrated that antisense walR RNA will be a supplementary strategy in treating E. faecalis with irrigation agents.},
}
@article {pmid32652741,
year = {2020},
author = {Morghad, T and Hassaine, H and Boutarfi, Z and Gaouar, S and Bellifa, S and Meziani, Z},
title = {Bacteriological water quality and biofilm formation in the treatment system of the hemodialysis unit in Tlemcen, Algeria.},
journal = {Seminars in dialysis},
volume = {},
number = {},
pages = {},
doi = {10.1111/sdi.12898},
pmid = {32652741},
issn = {1525-139X},
abstract = {OBJECTIVE: To evaluate and compare the microbiological quality of osmosis water at the distribution loop, at the dialysis generator inlet and to study the prevalence of biofilm in the tubing.<br><br>METHODS: Microbiological analysis of 20 water loop samples, 10 water samples were taken at the machine entry and 10 pipe segments from tubing connecting the machines to the loop was done.<br><br>RESULTS: The bacterial enumeration results of the loop water vary from 90 to 150 CFU/mL, while the average number of bacteria at the entry of the machines was 182 CFU/mL. The counts of the adhered bacteria in the tubing were worrying with rates ranging from 4.30 to 6.74 Log CFU/ cm2 . Fifty percentage of the strains isolated were Bacillus, followed by Enterobacter cloacae 23.52%, Staphylococcus, and others such as Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumanii. More than half of the tubing strains were highly formative of biofilm, 13 strains with medium capacity and 10 were weakly.<br><br>CONCLUSION: This study indicates bacterial water contamination. The formation of a biofilm will certainly harm the effectiveness of the various disinfection methods in this unit. Water quality is influenced not only by the high rate of bacterial colonization, but also differences in standards for dialysis water.},
}
@article {pmid32652437,
year = {2020},
author = {Yu, Z and Pei, H and Li, Y and Yang, Z and Xie, Z and Hou, Q and Nie, C},
title = {Inclined algal biofilm photobioreactor (IABPBR) for cost-effective cultivation of lipid-rich microalgae and treatment of seawater-diluted anaerobically digested effluent from kitchen waste with the aid of phytohormones.},
journal = {Bioresource technology},
volume = {315},
number = {},
pages = {123761},
doi = {10.1016/j.biortech.2020.123761},
pmid = {32652437},
issn = {1873-2976},
abstract = {Previous study has demonstrated that freshwater can be replaced with seawater for dilution of feed to algal production and wastewater treatment, but high harvest cost in suspended-growth systems is still a troublesome limitation for large-scale production. Therefore, a novel inclined algal biofilm photobioreactor (IABPBR) was constructed for algal bioproduct production and treatment of seawater-diluted anaerobically digested effluent (SA) in this study. Fluffy polyester was selected as the best carrier for the algal biofilm among ten discarded materials. With the help of phytohormones, the viability of SDEC-18 was clearly enhanced and an algal biomass productivity of 5.66 g/m2/d was achieved. The SDEC-18 biofilm provided removal capacities of 0.65, 0.25 and 3.31 g/m2/d for TN, TP and COD. Phytohormones clearly enhanced the lipid biosynthesis, with an extraordinary lipid productivity of 3.98 g/m2/d being achieved. Moreover, an automatic harvesting system was designed for the efficient harvesting process during large-scale production.},
}
@article {pmid32651162,
year = {2020},
author = {Novotny, LA and Goodman, SD and Bakaletz, LO},
title = {Targeting a bacterial DNABII protein with a chimeric peptide immunogen or humanised monoclonal antibody to prevent or treat recalcitrant biofilm-mediated infections.},
journal = {EBioMedicine},
volume = {},
number = {},
pages = {102867},
doi = {10.1016/j.ebiom.2020.102867},
pmid = {32651162},
issn = {2352-3964},
abstract = {BACKGROUND: Chronic and recurrent bacterial diseases are recalcitrant to treatment due to the ability of the causative agents to establish biofilms, thus development of means to prevent or resolve these structures are greatly needed. Our approach targets the DNABII family of bacterial DNA-binding proteins, which serve as critical structural components within the extracellular DNA scaffold of biofilms formed by all bacterial species tested to date. DNABII-directed antibodies rapidly disrupt biofilms and release the resident bacteria which promote their subsequent clearance by either host immune effectors or antibiotics that are now effective at a notably reduced concentration.<br><br>METHODS: First, as a therapeutic approach, we used intact IgG or Fab fragments against a chimeric peptide immunogen designed to target protective epitopes within the DNA-binding tip domains of integration host factor to disrupt established biofilms in vitro and to mediate resolution of existing disease in vivo. Second, we performed preventative active immunisation with the chimeric peptide to induce the formation of antibody that blocks biofilm formation and disease development in a model of viral-bacterial superinfection. Further, toward the path for clinical use, we humanised a monoclonal antibody against the chimeric peptide immunogen, then characterised and validated that it maintained therapeutic efficacy.<br><br>FINDINGS: We demonstrated efficacy of each approach in two well-established pre-clinical models of otitis media induced by the prevalent respiratory tract pathogen nontypeable Haemophilus influenzae, a common biofilm disease.<br><br>INTERPRETATION: Collectively, our data revealed two approaches with substantive efficacy and potential for broad application to combat diseases with a biofilm component.<br><br>FUNDING: Supported by R01 DC011818 to LOB and SDG.},
}
@article {pmid32650496,
year = {2020},
author = {Roscetto, E and Masi, M and Esposito, M and Di Lecce, R and Delicato, A and Maddau, L and Calabrò, V and Evidente, A and Catania, MR},
title = {Anti-Biofilm Activity of the Fungal Phytotoxin Sphaeropsidin A Against Clinical Isolates of Antibiotic-Resistant Bacteria.},
journal = {Toxins},
volume = {12},
number = {7},
pages = {},
doi = {10.3390/toxins12070444},
pmid = {32650496},
issn = {2072-6651},
support = {E62F16001250003//Compagnia di San Paolo/ ; },
abstract = {Many pathogens involved in human infection have rapidly increased their antibiotic resistance, reducing the effectiveness of therapies in recent decades. Most of them can form biofilms and effective drugs are not available to treat these formations. Natural products could represent an efficient solution in discovering and developing new drugs to overcome antimicrobial resistance and treat biofilm-related infections. In this study, 20 secondary metabolites produced by pathogenic fungi of forest plants and belonging to diverse classes of naturally occurring compounds were evaluated for the first time against clinical isolates of antibiotic-resistant Gram-negative and Gram-positive bacteria. epi-Epoformin, sphaeropsidone, and sphaeropsidin A showed antimicrobial activity on all test strains. In particular, sphaeropsidin A was effective at low concentrations with Minimum Inhibitory Concentration (MIC) values ranging from 6.25 μg/mL to 12.5 μg/mL against all reference and clinical test strains. Furthermore, sphaeropsidin A at sub-inhibitory concentrations decreased methicillin-resistant S. aureus (MRSA) and P. aeruginosa biofilm formation, as quantified by crystal violet staining. Interestingly, mixtures of sphaeropsidin A and epi-epoformin have shown antimicrobial synergistic effects with a concomitant reduction of cytotoxicity against human immortalized keratinocytes. Our data show that sphaeropsidin A and epi-epoformin possess promising antimicrobial properties.},
}
@article {pmid32649279,
year = {2020},
author = {Ogasawara, H and Ishizuka, T and Hotta, S and Aoki, M and Shimada, T and Ishihama, A},
title = {Novel regulators of the csgD gene encoding the master regulator of biofilm formation in Escherichia coli K-12.},
journal = {Microbiology (Reading, England)},
volume = {},
number = {},
pages = {},
doi = {10.1099/mic.0.000947},
pmid = {32649279},
issn = {1465-2080},
abstract = {Under stressful conditions, Escherichia coli forms biofilm for survival by sensing a variety of environmental conditions. CsgD, the master regulator of biofilm formation, controls cell aggregation by directly regulating the synthesis of Curli fimbriae. In agreement of its regulatory role, as many as 14 transcription factors (TFs) have so far been identified to participate in regulation of the csgD promoter, each monitoring a specific environmental condition or factor. In order to identify the whole set of TFs involved in this typical multi-factor promoter, we performed in this study 'promoter-specific transcription-factor' (PS-TF) screening in vitro using a set of 198 purified TFs (145 TFs with known functions and 53 hitherto uncharacterized TFs). A total of 48 TFs with strong binding to the csgD promoter probe were identified, including 35 known TFs and 13 uncharacterized TFs, referred to as Y-TFs. As an attempt to search for novel regulators, in this study we first analysed a total of seven Y-TFs, including YbiH, YdcI, YhjC, YiaJ, YiaU, YjgJ and YjiR. After analysis of curli fimbriae formation, LacZ-reporter assay, Northern-blot analysis and biofilm formation assay, we identified at least two novel regulators, repressor YiaJ (renamed PlaR) and activator YhjC (renamed RcdB), of the csgD promoter.},
}
@article {pmid32646902,
year = {2020},
author = {Cavalcanti, GS and Wasserscheid, J and Dewar, K and Shikuma, NJ},
title = {Complete Genome Sequences of Two Marine Biofilm Isolates, Leisingera sp. nov. Strains 201A and 204H, Novel Representatives of the Roseobacter Group.},
journal = {Microbiology resource announcements},
volume = {9},
number = {28},
pages = {},
doi = {10.1128/MRA.00505-20},
pmid = {32646902},
issn = {2576-098X},
abstract = {Here, we report the complete-genome assemblies of biofilm isolates 201A and 204H. They possess six and seven plasmids, respectively, with a size ranging from 44 kb to 159 kb. Genomic comparisons place the two strains into one new species belonging to the genus Leisingera as novel representatives of the Roseobacter group.},
}
@article {pmid32644968,
year = {2020},
author = {Schraa, O and Rosenthal, A and Wade, MJ and Rieger, L and Miletić, I and Alex, J},
title = {Assessment of aeration control strategies for biofilm-based partial nitritation/anammox systems.},
journal = {Water science and technology : a journal of the International Association on Water Pollution Research},
volume = {81},
number = {8},
pages = {1757-1765},
doi = {10.2166/wst.2020.174},
pmid = {32644968},
issn = {0273-1223},
abstract = {The objective of this work was to compare the nitrogen removal in mainstream, biofilm-based partial nitritation anammox (PN/A) systems employing (1) constant setpoint dissolved oxygen (DO) control, (2) intermittent aeration, and (3) ammonia-based aeration control (ABAC). A detailed water resource recovery facility (WRRF) model was used to study the dynamic performance of these aeration control strategies with respect to treatment performance and energy consumption. The results show that constant setpoint DO control cannot meet typical regulatory limits for total ammonia nitrogen (NHx-N). Intermittent aeration shows improvement but requires optimisation of the aeration cycle. ABAC shows the best treatment performance with the advantages of continuous operation and over 20% lower average energy consumption as compared to intermittent aeration.},
}
@article {pmid32640544,
year = {2020},
author = {Minami, M and Takase, H and Taira, M and Makino, T},
title = {Suppressive Effects of Hainosan (Painongsan) against Biofilm Production by Streptococcus mutans.},
journal = {Dentistry journal},
volume = {8},
number = {3},
pages = {},
doi = {10.3390/dj8030071},
pmid = {32640544},
issn = {2304-6767},
abstract = {Streptococcus mutans, a bacterium that causes dental plaques, forms a biofilm on tooth surfaces. This biofilm can cause gingivitis by stimulating the gingival margin. However, there is no established treatment for biofilm removal. Hainosan (Painongsan), a traditional Japanese Kampo formula, has been used to treat gingivitis. Therefore, we investigated the biofilm suppressive effects of the hainosan extract (HNS) and its components on S. mutans. We conducted scanning electron microscopy and confocal laser microscopy analyses to clarify the anti-biofilm activities of HNS and its crude drugs. We also performed a quantitative RT-PCR assay to assess the biofilm-related gene expression. HNS showed a significant dose-dependent suppressive effect on biofilm formation. Both the scanning electron microscopy and confocal laser microscopy analyses also revealed the significant inhibitory effects of the extract on biofilm formation. Transmission electron microscopy analysis showed that HNS disrupted the surface of the bacterial wall. Furthermore, HNS reduced the hydrophobicity of the bacteria, and suppressed the mRNA expression of β-glucosyltransferase (gtfB), glucosyltransferase-SI (gtfC), and fructosyltransferase (ftf). Among the constituents of hainosan, the extract of the root of Platycodon grandiflorum (PG) showed the strongest biofilm suppression effect. Platycodin D, one of the constituent natural compounds of PG, inhibited S. mutans-associated biofilm. These findings indicate that hainosan eliminates dental plaques by suppressing biofilm formation by S. mutans.},
}
@article {pmid32640045,
year = {2020},
author = {Gonzalez, T and Stevens, ML and Baatrebek Kyzy, A and Alarcon, R and He, H and Kroner, JW and Spagna, D and Grashel, B and Sidler, E and Martin, LJ and Biagini Myers, JM and Khurana Hershey, GK and Herr, AB},
title = {Biofilm propensity of Staphylococcus aureus skin isolates is associated with increased atopic dermatitis severity and barrier dysfunction in the MPAACH pediatric cohort.},
journal = {Allergy},
volume = {},
number = {},
pages = {},
doi = {10.1111/all.14489},
pmid = {32640045},
issn = {1398-9995},
abstract = {BACKGROUND: Atopic dermatitis (AD) patients are often colonized with Staphylococcus aureus and staphylococcal biofilms have been reported on adult AD skin lesions. The commensal Staphylococcus epidermidis can antagonize S. aureus, although its role in AD is unclear. We sought to characterize S. aureus and S. epidermidis colonization and biofilm propensity and determine their associations with AD severity, barrier function, and epidermal gene expression in the first US early-life cohort of children with AD, the Mechanisms of Progression of Atopic Dermatitis to Asthma in Children (MPAACH).<br><br>METHODS: The biofilm propensity of staphylococcal isolates was assessed by crystal violet assays. Gene expression of filaggrin and anti-microbial alarmins S100A8 and S100A9 was measured in keratinocyte RNA extracted from skin tape strips. Staphylococcal biofilms sampled from MPAACH skin were visualized using scanning electron microscopy.<br><br>RESULTS: Sixty-two percent of staphylococcal isolates (sampled from 400 subjects) formed moderate/strong biofilms. Sixty-eight percent of subjects co-colonized with both staphylococcal species exhibited strains that formed cooperative mixed-species biofilms. Scanning electron microscopy verified the presence of staphylococcal biofilms on the skin of MPAACH children. S. aureus strains showing higher relative biofilm propensity compared to S. epidermidis were associated with increased AD severity (p=0.03) and increased lesional and non-lesional transepidermal water loss (p=0.01, p=0.03).<br><br>CONCLUSIONS: Our data suggest a pathogenic role for S. aureus biofilms in AD. We found that strain-level variation in staphylococcal isolates governs the interactions between S. epidermidis and S. aureus, and that the balance between these two species, and their biofilm propensity, has important implications for AD.},
}
@article {pmid32637741,
year = {2020},
author = {Han, W and Zhou, B and Yang, K and Xiong, X and Luan, S and Wang, Y and Xu, Z and Lei, P and Luo, Z and Gao, J and Zhan, Y and Chen, G and Liang, L and Wang, R and Li, S and Xu, H},
title = {Biofilm-inspired adhesive and antibacterial hydrogel with tough tissue integration performance for sealing hemostasis and wound healing.},
journal = {Bioactive materials},
volume = {5},
number = {4},
pages = {768-778},
doi = {10.1016/j.bioactmat.2020.05.008},
pmid = {32637741},
issn = {2452-199X},
abstract = {Uncontrolled bleeding and infection can cause significant increases in mortalities. Hydrogel sealants have attracted extensive attention for their ability to control bleeding. However, because interfacial water is a formidable barrier to strong surface bonding, a challenge remains in finding a product that offers robust tissue adhesion combined with anti-infection properties. Inspired by the strong adhesive mechanism of biofilm and mussels, we report a novel dual bionic adhesive hydrogel (DBAH) based on chitosan grafted with methacrylate (CS-MA), dopamine (DA), and N-hydroxymethyl acrylamide (NMA) via a facile radical polymerization process. CS-MA and DA were simultaneously included in the adhesive polymer for imitating the two key adhesive components: polysaccharide intercellular adhesin (PIA) of staphylococci biofilm and 3,4-dihydroxy-l-phenylalanine (Dopa) of mussel foot protein, respectively. DBAH presented strong adhesion at 34 kPa even upon three cycles of full immersion in water and was able to withstand up to 168 mm Hg blood pressure, which is significantly higher than the 60-160 mm Hg measured in most clinical settings. Most importantly, these hydrogels presented outstanding hemostatic capability under wet and dynamic in vivo movements while displaying excellent antibacterial properties and biocompatibility. Therefore, DBAH represents a promising class of biomaterials for high-efficiency hemostasis and wound healing.},
}
@article {pmid32636429,
year = {2020},
author = {Elamary, RB and Albarakaty, FM and Salem, WM},
title = {Efficacy of Acacia nilotica aqueous extract in treating biofilm-forming and multidrug resistant uropathogens isolated from patients with UTI syndrome.},
journal = {Scientific reports},
volume = {10},
number = {1},
pages = {11125},
doi = {10.1038/s41598-020-67732-w},
pmid = {32636429},
issn = {2045-2322},
abstract = {Escherichia coli is the dominant bacterial cause of UTI among the uropathogens in both developed and developing countries. This study is to investigate the effect of Acacia nilotica aqueous extract on the survival and biofilm of isolated pathogens to reduce UTIs diseases. A total of 170 urine samples were collected from Luxor general hospital and private medical analysis laboratories in Luxor providence, Egypt. Samples were screened for the incidence of uropathogens by biochemical tests, antibiotics susceptibility, detection of virulence, and antibiotic-resistant genes by multiplex PCR, biofilm formation, and time-killing assay. Escherichia coli is by far the most prevalent causative agent with the percentage of 73.7% followed by Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeuroginosa, and Acinetobacter baumanii. Isolates were multidrug-resistant containing blaTEM, blaSHV, blaCTX, qnrs, and aac(3)-Ia resistant genes. All isolates were sensitive to 15-16.7 mg ml-1 of Acacia nilotica aqueous extract. Time killing assay confirmed the bactericidal effect of the extract over time (20-24 h). A high percentage of 3-Cyclohexane-1-Carboxaldehyde, 2,6,6-trimethyl (23.5%); á-Selinene (15.12%); Oleic Acid (14.52%); Globulol (11.35%) were detected among 19 bioactive phytochemical compounds in the aqueous extract of A. nilotica over the GC-mass spectra analysis. The plant extract reduced significantly the biofilm activity of E. coli, K. pneumoniae, P. mirabilis, and P. aeuroginosa by 62.6, 59. 03, 48.9 and 39.2%, respectively. The challenge to improve the production of A. nilotica phytochemicals is considered a very low price for the return.},
}
@article {pmid32636245,
year = {2020},
author = {Freiberg, JA and Le Breton, Y and Harro, JM and Allison, DL and McIver, KS and Shirtliff, ME},
title = {The Arginine Deiminase Pathway Impacts Antibiotic Tolerance during Biofilm-Mediated Streptococcus pyogenes Infections.},
journal = {mBio},
volume = {11},
number = {4},
pages = {},
doi = {10.1128/mBio.00919-20},
pmid = {32636245},
issn = {2150-7511},
abstract = {Bacterial biofilms are responsible for a variety of serious human infections and are notoriously difficult to treat due to their recalcitrance to antibiotics. Further work is necessary to elicit a full understanding of the mechanism of this antibiotic tolerance. The arginine deiminase (ADI) pathway is responsible for bacterial pH maintenance and is highly expressed during biofilm growth in multiple bacterial species. Using the group A Streptococcus (GAS) as a model human pathogen, the ADI pathway was demonstrated to contribute to biofilm growth. The inability of antibiotics to reduce GAS populations when in a biofilm was demonstrated by in vitro studies and a novel animal model of nasopharyngeal infection. However, disruption of the ADI pathway returned GAS biofilms to planktonic levels of antibiotic sensitivity, suggesting the ADI pathway is influential in biofilm-related antibiotic treatment failure and provides a new strategic target for the treatment of biofilm infections in GAS and potentially numerous other bacterial species.IMPORTANCE Biofilm-mediated bacterial infections are a major threat to human health because of their recalcitrance to antibiotic treatment. Through the study of Streptococcus pyogenes, a significant human pathogen that is known to form antibiotic-tolerant biofilms, we demonstrated the role that a bacterial pathway known for responding to acid stress plays in biofilm growth and antibiotic tolerance. This not only provides some insight into antibiotic treatment failure in S. pyogenes infections but also, given the widespread nature of this pathway, provides a potentially broad target for antibiofilm therapies. This discovery has the potential to impact the treatment of many different types of recalcitrant biofilm infections.},
}
@article {pmid32636243,
year = {2020},
author = {Park, JS and Choi, HY and Kim, WG},
title = {The Nitrite Transporter Facilitates Biofilm Formation via Suppression of Nitrite Reductase and Is a New Antibiofilm Target in Pseudomonas aeruginosa.},
journal = {mBio},
volume = {11},
number = {4},
pages = {},
doi = {10.1128/mBio.00878-20},
pmid = {32636243},
issn = {2150-7511},
abstract = {Biofilm-forming bacteria, including the Gram-negative Pseudomonas aeruginosa, cause multiple types of chronic infections and are responsible for serious health burdens in humans, animals, and plants. Nitric oxide (NO) has been shown to induce biofilm dispersal via triggering a reduction in cyclic-di-GMP levels in a variety of bacteria. However, how NO, at homeostatic levels, also facilitates biofilm formation is unknown. Here, we found that complestatin, a structural analog of vancomycin isolated from Streptomyces, inhibits P. aeruginosa biofilm formation by upregulating NO production via nitrite reductase (NIR) induction and c-di-GMP degradation via phosphodiesterase (PDE) stimulation. The complestatin protein target was identified as a nitrite transporter from a genome-wide screen using the Keio Escherichia coli knockout library and confirmed using nitrite transporter knockout and overexpression strains. We demonstrated that the nitrite transporter stimulated biofilm formation by controlled NO production via appropriate NIR suppression and subsequent diguanylate cyclase (DGC) activation, not PDE activity, and c-di-GMP production in E. coli and P. aeruginosa Thus, this study provides a mechanism for NO-mediated biofilm formation, which was previously not understood.IMPORTANCE Bacterial biofilms play roles in infections and avoidance of host defense mechanisms of medically important pathogens and increase the antibiotic resistance of the bacteria. Nitric oxide (NO) is reported to be involved in both biofilm formation and dispersal, which are conflicting processes. The mechanism by which NO regulates biofilm dispersal is relatively understood, but there are no reports about how NO is involved in biofilm formation. Here, by investigating the mechanism by which complestatin inhibits biofilm formation, we describe a novel mechanism for governing biofilm formation in Escherichia coli and Pseudomonas aeruginosa Nitrite transporter is required for biofilm formation via regulation of NO levels and subsequent c-di-GMP production. Additionally, the nitrite transporter contributes more to P. aeruginosa virulence than quorum sensing. Thus, this study identifies nitrite transporters as new antibiofilm targets for future practical and therapeutic agent development.},
}
@article {pmid32634677,
year = {2020},
author = {Lai, CY and Song, Y and Wu, M and Lu, X and Wang, Y and Yuan, Z and Guo, J},
title = {Microbial selenate reduction in membrane biofilm reactors using ethane and propane as electron donors.},
journal = {Water research},
volume = {183},
number = {},
pages = {116008},
doi = {10.1016/j.watres.2020.116008},
pmid = {32634677},
issn = {1879-2448},
abstract = {Selenate (Se(VI)) contamination in groundwater is one of major concerns for human health, in particular in shale gas extraction sites. Microbial selenate reduction coupled to methane (CH4) oxidation has been demonstrated very recently. Little is known whether ethane (C2H6) and butane (C3H8) are able to drive selenate reduction, although they are also important components in shale gas. In this study, we demonstrated Se(VI) bio-reduction could be achieved using C2H6 and C3H8 as electron donors and carbon sources. Scanning electron microscopy coupled to energy dispersive X-ray spectroscopy (SEM-EDX) confirmed elemental Se (Se0) was the major final product formed from Se(VI) bio-reduction. Polyhydroxyalkanoates (PHAs) were generated in the biofilms as the internal electron-storage materials, which were consumed for sustaining Se(VI) bio-reduction in absence of C2H6 and C3H8. Microbial community analysis showed that two genera capable of oxidizing gaseous alkanes dominated in the biofilms, including Mycobacterium (in both C2H6 and C3H8-fed biofilms) and Rhodococcus (in C3H8-fed biofilm). In addition, several potential Se(VI) reducers (e.g., Variovorax) were detected in the biofilms. Investigation of Communities by Reconstruction of Unobserved States analysis supported that predictive genes associated with alkanes oxidation, denitrification and PHAs cycle were enriched in the biofilms. These findings offer insights into the process of selenate reduction driven by C2H6 and C3H8, which ultimately may help to develop a solution to use shale gas for groundwater remediation, especially near shale gas exploitation sites.},
}
@article {pmid32634643,
year = {2020},
author = {Lin, Z and Huang, W and Zhou, J and He, X and Wang, J and Wang, X and Zhou, J},
title = {The variation on nitrogen removal mechanisms and the succession of ammonia oxidizing archaea and ammonia oxidizing bacteria with temperature in biofilm reactors treating saline wastewater.},
journal = {Bioresource technology},
volume = {314},
number = {},
pages = {123760},
doi = {10.1016/j.biortech.2020.123760},
pmid = {32634643},
issn = {1873-2976},
abstract = {To reveal nitrogen removal mechanisms under environmental stresses, biofilm reactors were operated at different temperatures (10 °C-35 °C) treating saline wastewater (salinity 3%). The results showed nitrogen removal efficiency was 98.46% at 30 °C and 60.85% at 10 °C, respectively. Both ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) participated in nitrification. 94.9% of the overall ammonia oxidation was attributed to AOA at 10 °C, but only 48.2% of that was undertaken by AOA at 35 °C. AOA had a greater contribution at low temperature, which demonstrated that nitrogen removal pathway varied with temperature. Aerobic denitrification was more stable than anoxic denitrification. High-throughput sequencing showed Crenarchaeota was the dominant AOA (97.02-34.47%), cooperating with various heterotrophic AOB. Real-time PCR indicated that AOA was three orders of magnitude more abundant than AOB. AOA was more resistant to low temperature and high-saline stresses. Ammonia oxidizers had distinct responses to temperature change and showed diverse relationships at different temperatures.},
}
@article {pmid32634470,
year = {2020},
author = {de Sá Almeida, JS and de Oliveira Marre, AT and Teixeira, FL and Boente, RF and Domingues, RMCP and de Paula, GR and Lobo, LA},
title = {Lactoferrin and lactoferricin B reduce adhesion and biofilm formation in the intestinal symbionts Bacteroides fragilis and Bacteroides thetaiotaomicron.},
journal = {Anaerobe},
volume = {},
number = {},
pages = {102232},
doi = {10.1016/j.anaerobe.2020.102232},
pmid = {32634470},
issn = {1095-8274},
abstract = {Several factors affect the composition of species that inhabit our intestinal tract, including mode of delivery, genetics and nutrition. Antimicrobial peptides and proteins secreted in the gastrointestinal tract are powerful tools against bacteria. Lactoferrin (LF) inhibits the growth of several bacterial species, such as Enterobacteriaceae, but may stimulate probiotic bacteria. Activity of LF against gut symbiotic species of the Bacteroides genus could give us insights on how these species colonize the gut. We investigated the effects of the antimicrobial protein lactoferrin and its derived peptide, lactoferricin B on two species of strict anaerobes, opportunistic pathogens that cause diseases in both adults and children, commonly found in the microbiota of the human gastrointestinal tract, Bacteroides fragilis and B. thetaiotaomicron., In vitro biofilm formation and binding to laminin were strongly inhibited by a low concentration of lactoferrin (12.5 μg/ml). Conversely, the growth of the strains in a micro-dilution assay in minimal media with different iron sources was not affected by physiological concentrations (2 mg/ml) of apo-lactoferrin or holo-lactoferrin. The combination of lactoferrin with antibiotics in synergism assays was also negative. The lactoferricin B fragment was also unable to inhibit growth in a similar test with concentrations of up to 32 μg/ml. Resistance to lactoferrin could confer an advantage to these species, even when high amount of this protein is present in the gastrointestinal tract. However, colonization is hampered by the binding and biofilm inhibitiory effect of lactoferrin, which may explain the low prevalence of Bacteroides in healthy babies. Resistance to this antimicrobial protein may help understand the success of these opportunistic pathogens during infection in the peritoneum.},
}
@article {pmid32633012,
year = {2020},
author = {Yin, L and Zhu, W and Chen, D and Zhou, Y and Lin, H},
title = {Small noncoding RNA sRNA0426 is involved in regulating biofilm formation in Streptococcus mutans.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e1096},
doi = {10.1002/mbo3.1096},
pmid = {32633012},
issn = {2045-8827},
support = {81570967//National Natural Science Foundation of China/ ; },
abstract = {Evidence suggests that small noncoding RNAs (sRNAs) are involved in the complex regulatory networks governing biofilm formation. Few studies have investigated the role of sRNAs in Streptococcus mutans (S. mutans). In the present study, the association between sRNA and biofilm formation in S. mutans was explored. sRNAs that are differentially expressed in the biofilm and planktonic states of this bacterium were identified by quantitative real-time PCR (qRT-PCR). Confocal laser scanning microscopy was used to investigate the characteristics of biofilm formation in a standard strain of S. mutans (UA159, ATCC 700610) and ten clinical strains. Bioinformatics analyses were employed to predict and examine potential sRNA regulatory pathways. The results showed that sRNA0426 has a strong positive relationship with dynamic biofilm formation. Moreover, sRNA0426 expression was positively correlated with exopolysaccharide (EPS) production. Bioinformatics analyses showed that sRNA0426 is involved in biofilm formation such as metabolic pathways, especially carbon metabolism. Five target mRNAs (GtfB, GtfC, GtfD, ComE, and CcpA) involved in the synthesis of EPS were selected for further evaluation; the expression levels of three of these mRNAs (GtfB, GtfC, and CcpA) were positively correlated with sRNA0426 expression levels, and the expression level of one (ComE) was negatively correlated. In conclusion, the results suggested that sRNA0426 may play an important and positive role in the biofilm formation of S. mutans and provide novel insight into the S. mutans biofilm regulatory network.},
}
@article {pmid32632872,
year = {2020},
author = {Thibeaux, R and Kainiu, M and Goarant, C},
title = {Biofilm Formation and Quantification Using the 96-Microtiter Plate.},
journal = {Methods in molecular biology (Clifton, N.J.)},
volume = {2134},
number = {},
pages = {207-214},
doi = {10.1007/978-1-0716-0459-5_19},
pmid = {32632872},
issn = {1940-6029},
abstract = {Biofilm formation in microtiter plates is certainly the most commonly used method to grow and study biofilm. This simple design is very popular due to its high-throughput screening capacities, low cost, and easy handling. In the protocol described here, we focus on the use of 96-well optically clear, polystyrene flat-bottom plate to study biofilm formation by Leptospira spp. and quantify the biofilm formation by crystal violet (CV) staining. We also describe an alternative method, based on phase contrast image analysis that we believe is more suitable for accurately quantifying biofilm growth by reducing handling of this fragile structure.},
}
@article {pmid32631946,
year = {2020},
author = {Collins, AJ and Pastora, AB and Smith, TJ and O'Toole, GA},
title = {MapA, a second large RTX adhesin conserved across the Pseudomonads, contributes to biofilm formation by Pseudomonas fluorescens.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00277-20},
pmid = {32631946},
issn = {1098-5530},
abstract = {Mechanisms by which cells attach to a surface and form a biofilm are diverse and differ greatly among organisms. The Gram-negative, Gammaproteobacterium Pseudomonas fluorescens attaches to a surface through the localization of the large type 1-secreted RTX adhesin LapA to the outer surface of the cell. LapA localization to the cell surface is controlled by the activities of a periplasmic protease, LapG and an inner-membrane spanning cyclic di-GMP responsive effector protein, LapD. A previous study identified a second, LapA-like protein encoded in the P. fluorescens Pf0-1 genome: Pfl01_1463. Here, we identified specific growth conditions wherein, Pfl01_1463, hereafter called MapA (Medium Adhesion Protein A) is a functional adhesin contributing to biofilm formation. This adhesin, like LapA, appears to be secreted through a Lap-related type 1 secretion machinery and its localization is controlled by LapD and LapG. However, differing roles of LapA and MapA in biofilm formation are achieved, at least in part, through the differences in the sequences of the two adhesins and different distributions of the expression of the lapA and mapA genes within a biofilm. LapA-like proteins are broadly distributed throughout the Proteobacteria, and furthermore, LapA and MapA are well conserved among other Pseudomonas species. Together, our data indicate that the mechanisms by which a cell forms a biofilm and the components of a biofilm matrix can differ depending on growth conditions and the matrix protein(s) expressed.Importance Adhesins are critical for the formation and maturation of bacterial biofilms. We identify a second adhesin in P. fluorescens, called MapA, which appears to play a role in biofilm maturation and whose regulation is distinct from the previously reported LapA adhesin, which is critical for biofilm initiation. Analysis of bacterial adhesins show that LapA-like and MapA-like adhesins are found broadly in Pseudomonads and related organisms, indicating that the utilization of different suites of adhesins may be broadly important in the Gammaproteobacteria.},
}
@article {pmid32631880,
year = {2020},
author = {Dal Co, A and Brenner, MP},
title = {Tracing cell trajectories in a biofilm.},
journal = {Science (New York, N.Y.)},
volume = {369},
number = {6499},
pages = {30-31},
doi = {10.1126/science.abd1225},
pmid = {32631880},
issn = {1095-9203},
}
@article {pmid32624830,
year = {2017},
author = {Mulansky, S and Saballus, M and Friedrichs, J and Bley, T and Boschke, E},
title = {A novel protocol to prepare cell probes for the quantification of microbial adhesion and biofilm initiation on structured bioinspired surfaces using AFM for single-cell force spectroscopy: Dedicated to Prof. em. Dr. Dr. H.C. Karl Schügerl on the occasion of his 90th birthday.},
journal = {Engineering in life sciences},
volume = {17},
number = {8},
pages = {833-840},
pmid = {32624830},
issn = {1618-0240},
abstract = {We present a novel protocol that uses single-cell force spectroscopy to characterize the bacteria-to-surface interactions involved in early steps of biofilm formation. Bacteria are immobilized as a monolayer by electrostatic interactions on a polyethylenimine-coated silica bead, and the Escherichia coli-bead complex is then glued on a tipless cantilever. We validated our new protocol by comparing to earlier published methods using single bacteria, but in contrast to these, which carry out bacterial attachment to the bead after fixation to the cantilever, our protocol results in more reliable production of usable cell probes. Measurements of interactions of E. coli with bio-inspired surfaces by single-cell force spectroscopy yielded comparable detachment forces to those found with the previous methods.},
}
@article {pmid32628991,
year = {2020},
author = {Mahdi, LH and Ghufran Nazem, AH and Auda, IG},
title = {Evidence of anti- K. pneumoniae biofilm activity of novel Entrococcus faecalis enterocin GLHM.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {104366},
doi = {10.1016/j.micpath.2020.104366},
pmid = {32628991},
issn = {1096-1208},
abstract = {Many enterocins were produced from the lactic acid bacteria, Enterococcus faecalis, they belonged to different types of bacteriocins and have different characteristics. The present study aimed to search for another enterocin and test its ability to inhibit Klebsiella pneumoniae biofilm as compared with the most effective antibacterial agent. E. faecalis isolates were isolated from stools of breastfeeding babies. Klebsiella pneumoniae isolates were from urinary tract infections and urinary catheters. K. pneumoniae isolates showed biofilm formation potential and multidrug resistance phenotype but amikacin was the most effective one. Enterocin production by gene harboring E. faecalis was screened, then enterocin was purified, characterized, and antibacterial activity and MIC of enterocin were determined. Produced enterocin has characteristics differ from other discovered enterocins. Furthermore, the crude and purified enterocin of E. faecalis possess significant antibacterial activity against K. pneumoniae isolates as compare with control (p < 0.05), and antibiofilm activity of enterocin was stronger than the antibiofilm activity of amikacin (P < 0.05), as well as the enterocin, was potent than the amikacin in preventing the formation of biofilm on the catheter. In conclusion, a novel enterocin was produced from Enterococcus faecalis (enterocin GLHM) is proteinous bacteriocin, relatively heat-stable and have full activity at neutral pH and was belong to type II bacteriocin. Enterocin GLHM have anti-K. pneumoniae and anti-K. pneumoniae biofilm significantly better than amikacin.},
}
@article {pmid32623704,
year = {2020},
author = {Donmez, HG and Sahal, G and Akgor, U and Cagan, M and Ozgul, N and Beksac, MS},
title = {The relationship between the presence of HPV infection and biofilm formation in cervicovaginal smears.},
journal = {Infection},
volume = {},
number = {},
pages = {},
doi = {10.1007/s15010-020-01478-5},
pmid = {32623704},
issn = {1439-0973},
abstract = {PURPOSE: To demonstrate and understand the association of HPV infection and biofilm formation.<br><br>METHODS: The study consisted of cervicovaginal samples of 72 women who were evaluated at the colposcopy unit. Papanicolaou staining was used for cytological examination while &quot;Crystal Violet Binding&quot; assay was performed to detect biofilm formation.<br><br>RESULTS: HPV-DNA was positive in 55.5% (n = 40) of the patients. The biofilm formation rate was statistically significantly higher in the HPV-positive women (45%) compared to HPV-negative women (21.9%) (P < 0.05). There was a statistically significant relationship between the presence of single HPV and &quot;high-risk HPV&quot; types and biofilm formation (P < 0.05). Biofilm formation was found in 80% of women with abnormal smear demonstrating atypical epithelial cells (P < 0.05).<br><br>CONCLUSION: Biofilm formation is more frequent at the cervicovaginal microbiota of patients with HPV infection. This finding is especially important in cases with atypical epithelial cells at their cervicovaginal smears.},
}
@article {pmid32623133,
year = {2020},
author = {Kunrath, MF and Monteiro, MSG and Gupta, S and Hubler, R and de Oliveira, SD},
title = {Influence of titanium and zirconia modified surfaces for rapid healing on adhesion and biofilm formation of Staphylococcus epidermidis.},
journal = {Archives of oral biology},
volume = {117},
number = {},
pages = {104824},
doi = {10.1016/j.archoralbio.2020.104824},
pmid = {32623133},
issn = {1879-1506},
abstract = {OBJECTIVE: Surface alterations have been employed to enhance the osseointegration process in biomedical implants. However, these modifications may influence bacterial adhesion in different ways. Therefore, this study developed five different surfaces and evaluated the Staphylococcus epidermidis growth in early (1 h) and late (24 h) contact.<br><br>DESIGN: The Titanium (Ti) and Zirconia (Zr) surfaces were divided in five groups and characterized concerning your morphology, roughness, wettability and chemical surface composition. Then, were evaluated regarding bacterial adhesion and biofilm formation/thickness, viability and morphology.<br><br>RESULTS: Different topographies were manufactured resulting in a variety of combinations of surface properties. High roughness showed significantly higher bacterial adhesion in 1 h, while high hydrophilicity revealed greater bacterial proliferation in 24 h. Morphological changes were not found visually, however the viability test showed some cell membrane damage in the Ti micro and nano groups.<br><br>CONCLUSIONS: Finally, surface distinct properties influence the growth of S. epidermidis independent of the based-material. Furthermore, some surface properties require precautions for use in contaminated sites according to the increased adhesion of S. epidermidis presented when in contact.},
}
@article {pmid32622258,
year = {2020},
author = {Ayoub, HM and Gregory, RL and Tang, Q and Lippert, F},
title = {The anti-caries efficacy of three fluoride compounds at increasing maturation of a microcosm biofilm.},
journal = {Archives of oral biology},
volume = {117},
number = {},
pages = {104781},
doi = {10.1016/j.archoralbio.2020.104781},
pmid = {32622258},
issn = {1879-1506},
abstract = {OBJECTIVE: To explore the anti-caries efficacy of three fluoride compounds at increasing maturation of a microcosm biofilm.<br><br>DESIGN: Microcosm biofilm, obtained from saliva collected from three donors (IRB #1406440799), was grown on enamel samples (n = 18/group) for 24-h (Brain Heart Infusion; 0.2 % sucrose). Then, pH cycling model started. Three maturations were explored (4d, 8d, and 12d). The pH cycling consisted of daily 2 × 5 min treatments (NaF, SnF2, AmF: 287.5 ppm F, and de-ionized water [DIW]), 4 × 10 min remineralization (BHI, no sucrose, pH 7.0), and 3 × 2:15 h demineralization (BHI, 1% sucrose, pH 4.5). We analyzed the enamel (surface microhardness [VHNchange], integrated mineral loss [ΔZ], lesion depth [L]), and the biofilm (viability [log10 CFU/mL], lactic acid production [LDH], and exopolysaccharide [EPS] amount). Data were analyzed using two-way ANOVA (p = 0.05).<br><br>RESULTS: The interaction between tested variables was significant for VHNchange, viability, LDH, EPS (p = 0.0354, p = 0.0001, p < 0.0001, p < 0.0001), but not for L (p = 0.2412) or ΔZ (p = 0.6811). LDH and EPS analyses exhibited more tolerance of mature biofilm against NaF (LDH and EPS p < 0.0001); NaF-treated groups demonstrated significantly lower results than the control in the 12d group. The effect of SnF2 and AmF continued over time. VHNchange, L, and ΔZ: The effect of SnF2 and AmF was higher than NaF and DIW. L and ΔZ did not result in significant differences over time (all treatments). Within each maturation, fluoride compounds demonstrated statistically significantly lower L and ΔZ values than DIW.<br><br>CONCLUSIONS: Biofilm's maturation may influence the selection of fluoride compounds to achieve an optimum cariostatic effect.},
}
@article {pmid32622167,
year = {2020},
author = {Hou, YN and Ma, JF and Yang, ZN and Sun, SY and Wang, AJ and Cheng, HY},
title = {Insight into the electrocatalytic performance of in-situ fabricated electroactive biofilm-Pd: The role of biofilm thickness, initial Pd(II) concentration and the exposure time to Pd precursor.},
journal = {The Science of the total environment},
volume = {742},
number = {},
pages = {140536},
doi = {10.1016/j.scitotenv.2020.140536},
pmid = {32622167},
issn = {1879-1026},
abstract = {Biogenic palladium (bio-Pd) nanoparticles have been considered as promising biocatalyst for energy generation and contaminants remediation in water and sediment. Recently, an electroactive biofilm-Pd (EAB-Pd) network, which can be used directly as electrocatalyst and show enhanced electrocatalytic performance, has exhibited tremendous application potential. However, the information regarding to the controllable biosynthetic process and corresponding catalytic properties is scarce. This study demonstrated that the catalytic performance of EAB-Pd could be influenced by Pd loading on bacteria cells (Pd/cells), which was crucial to determine the final distribution characteristic of Pd nanocrystal on EAB skeleton. For instance, the high Pd/cells (over 0.18 pg cell-1) exhibited almost 6-fold and 1.5-fold enhancement over EAB-Pds with Pd/cells below 0.03 in catalytic current toward hydrogen evolution reaction and nitrobenzene reduction, respectively. In addition, the Pd/cells was found to be affected by the synthesis factors, such as the ratio of biomass to initial Pd(II) concentration (cells/PdII) and the exposure time of EAB to Pd(II) precursor solution. The Pd/cells increased significantly as the cell/PdII ratio decreased from ~5.5 × 107 to ~1.3 × 107 cells L mg-1 or the prolongation of exposure time from 3 h to 24 h. The findings developed in this work extensively expand our knowledge for the in-situ designing biogenic electrocatalyst and provide important information for the development of its catalytic property.},
}
@article {pmid32622078,
year = {2020},
author = {Skariyachan, S and Ravishankar, R and Gopal, D and Muddebihalkar, AG and Uttarkar, A and Praveen, PKU and Niranjan, V},
title = {Response regulator GacA and transcriptional activator RhlR proteins involved in biofilm formation of Pseudomonas aeruginosa are prospective targets for natural lead molecules: Computational modelling, molecular docking and dynamic simulation studies.},
journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases},
volume = {},
number = {},
pages = {104448},
doi = {10.1016/j.meegid.2020.104448},
pmid = {32622078},
issn = {1567-7257},
abstract = {Pseudomonas aeruginosa has become a global concern due to its extreme resistance to most of the last resort antibiotics. Present study focuses on the screening of potential molecular targets involved in regulation of biofilm formation in P. aeruginosa and identification of potential natural lead molecules against these targets by molecular modelling, docking and simulation studies. Response regulator (GacA) and transcriptional activator (RhlR) involved in biofilm formation in P. aeruginosa were identified as molecular targets by metabolic pathway analysis and the three dimensional structures of these proteins were predicted by homology modelling and validated. By thorough literature survey, 78 lead molecules were screened and their pharmacokinetic profiles were determined and best two of them selected. The binding potential of selected lead molecules against GacA and RhlR were predicted by molecular docking and their binding energy was compared with the interaction of meropenem and its usual target penicillin binding protein-3. The stabilities of best docked complex were studied by molecular dynamic (MD) simulation. This study showed that Celastrol present in Celastrus paniculatus and Rotiorinol present in Chaetomium cupreum showed better binding affinities with GacA (binding energy -7.2 kcal/mol) and RhlR (binding energy -8.0 kcal/mol) respectively in comparison with the binding of Meropenem and its target (binding energy -6.2 kcal/mol). MD simulation studies showed that GacA-Celastrol and RhlR-Rotiorinol complexes demonstrated conformational stability throughout the simulation. This study highlights the application of GacA and RhlR as prospective targets and Celastrol and Rotiorinol are the potential lead molecules towards biofilm producing drug resistant P. aeruginosa.},
}
@article {pmid32621273,
year = {2020},
author = {Nagaram, P and Pasupuleti, M and Arockiaraj, J},
title = {CxxC Zinc Finger Protein Derived Peptide, MF18 Functions Against Biofilm Formation.},
journal = {The protein journal},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10930-020-09904-1},
pmid = {32621273},
issn = {1875-8355},
abstract = {The major threat in modern medicine was biofilm forming bacterial related infections and they were highly tolerant to conventional antibiotics and a boundless demand for new drugs. In this regard, antimicrobial peptide (AMP) have been considered as potential alternative agents to conventional antibiotics. In this study, we have reported a CxxC zinc finger protein derived peptide, MF18 and its various biological role including activity against biofilm forming bacteria. Zinc finger protein are important in regulation of several cellular processes and wide range of molecular functions. The CxxC zinc finger protein identified from the cDNA library of a teleost fish; further it was characterised using various online bioinformatics programs. During the in-silico analysis, an AMP named MF18 was identified from the CxxC zinc finger protein, then it was synthesised for further biological activity studies. The antimicrobial activity of MF18 was confirmed against the biofilm clinical isolates such as Staphylococcus aureus and Escherichia coli. The MIC of the antimicrobial peptide at the concentration of 320 µM was observed against these two biofilm bacteria. The mechanism of the peptides was determined using bacteria on its membrane permeabilization ability by scanning electron microscopy. It is exhibited that the MF18 potentially influenced in damaging the morphology of the bacteria. The toxicity of MF18 against the continuous cell line (RAW 264.7) was demonstrated by MTT assay and also using peripheral red blood cells by haemolytic assay; both assays showed that the peptide have no toxicity on the cells at lower concentration. Overall, the study showed the potential therapeutic application of the peptide in pharma industry.},
}
@article {pmid32621125,
year = {2020},
author = {Xiong, Q and Liu, D and Zhang, H and Dong, X and Zhang, G and Liu, Y and Zhang, R},
title = {Quorum sensing signal autoinducer-2 promotes root colonization of Bacillus velezensis SQR9 by affecting biofilm formation and motility.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-020-10713-w},
pmid = {32621125},
issn = {1432-0614},
support = {31670113//National Natural Science Foundation of China/ ; 31870096//National Natural Science Foundation of China/ ; 2018YFD0500201//National Key R &amp; D Program of China/ ; },
abstract = {Root colonization of beneficial rhizobacteria is critical for their beneficial effects. Quorum sensing (QS) has been reported to affect the colonization of many plant pathogens. However, how QS signals regulate root colonization of beneficial rhizobacteria is unclear. In this study, the QS signal AI-2 synthetase-encoding gene luxS was completely deleted from the genome of the plant beneficial rhizobacterium Bacillus velezensis SQR9, and bioluminescence experiments showed that AI-2 production was blocked. Deletion of luxS reduced biofilm formation, motility, and root colonization of B. velezensis SQR9, while addition of exogenous AI-2 to the mutant restored this phenomenon. These results indicated that AI-2 positively affects the root colonization of B. velezensis SQR9. This study provided new insights for enhancing the colonization of beneficial rhizobacteria. KEY POINTS: • LuxS participated in the synthesis of the quorum sensing signal AI-2 in B. velezensis. • AI-2 enhanced motility, biofilm formation, and root colonization of B. velezensis. • AI-2 stimulated the production of γ-polyglutamic acid by B. velezensis.},
}
@article {pmid32620785,
year = {2020},
author = {Daood, U and Matinlinna, JP and Pichika, MR and Mak, KK and Nagendrababu, V and Fawzy, AS},
title = {A quaternary ammonium silane antimicrobial triggers bacterial membrane and biofilm destruction.},
journal = {Scientific reports},
volume = {10},
number = {1},
pages = {10970},
doi = {10.1038/s41598-020-67616-z},
pmid = {32620785},
issn = {2045-2322},
abstract = {To study the antimicrobial effects of quaternary ammonium silane (QAS) exposure on Streptococcus mutans and Lactobacillus acidophilus bacterial biofilms at different concentrations. Streptococcus mutans and Lactobacillus acidophilus biofilms were cultured on dentine disks, and incubated for bacterial adhesion for 3-days. Disks were treated with disinfectant (experimental QAS or control) and returned to culture for four days. Small-molecule drug discovery-suite was used to analyze QAS/Sortase-A active site. Cleavage of a synthetic fluorescent peptide substrate, was used to analyze inhibition of Sortase-A. Raman spectroscopy was performed and biofilms stained for confocal laser scanning microscopy (CLSM). Dentine disks that contained treated dual-species biofilms were examined using scanning electron microscopy (SEM). Analysis of DAPI within biofilms was performed using CLSM. Fatty acids in bacterial membranes were assessed with succinic-dehydrogenase assay along with time-kill assay. Sortase-A protein underwent conformational change due to QAS molecule during simulation, showing fluctuating alpha and beta strands. Spectroscopy revealed low carbohydrate intensities in 1% and 2% QAS. SEM images demonstrated absence of bacterial colonies after treatment. DAPI staining decreased with 1% QAS (p < 0.05). Fatty acid compositions of dual specie biofilm increased in both 1% and 2% QAS specimens (p < 0.05). Quaternary ammonium silane demonstrated to be a potent antibacterial cavity disinfectant and a plaque inhibitor and can be of potential significance in eliminating caries-forming bacteria.},
}
@article {pmid32620725,
year = {2020},
author = {Kelten, OS and Hepdeniz, OK and Tuncer, Y and Kankaya, DA and Gurdal, O},
title = {Effect of surface characteristic of different restorative materials containing glass ionomer on Streptococcus mutans biofilm.},
journal = {Nigerian journal of clinical practice},
volume = {23},
number = {7},
pages = {957-964},
doi = {10.4103/njcp.njcp_538_19},
pmid = {32620725},
issn = {1119-3077},
abstract = {Aim: The aims of this study were to evaluate the surface morphology and surface roughness of restorative materials containing glass ionomer, analyze Streptococcus mutans biofilm formation on the surface of materials, and determine the correlation between surface roughness and biofilm.<br><br>Materials and Methods: Four restorative materials: resin-modified glass ionomer; giomer; amalgomer; and glass carbomer were used and for each material, 6 mm in diameter and 2 mm in thickness disc-shaped specimens were prepared to evaluate the surface morphology (n = 3), surface roughness (n = 16), and biofilm (n = 20). Surface morphology was analyzed with a scanning electron microscope. Surface roughness was evaluated via an atomic force microscope. The biofilm was evaluated by counting the colony-forming units. Surface roughness measurements were evaluated using a one-way analysis of variance and Tukey HSD test. Biofilm parameters were analyzed using the Kruskal-Wallis H and Mann-Whitney U test. Pearson's correlation test was used to determine the correlation between surface roughness and biofilm.<br><br>Results: While the highest roughness values were obtained for amalgomer and glass carbomer, the lowest roughness values belonged to giomer and resin-modified glass ionomer. Statistically significant differences in the number of adherent bacteria were observed between the materials only on day 1. No statistically significant correlation was determined between surface roughness and biofilm.<br><br>Conclusions: The resin content and small filler particle size of material positively affect surface roughness. However, there is no direct relationship between surface roughness and biofilm.},
}
@article {pmid32619807,
year = {2020},
author = {Zhang, P and Ding, XS and Zhao, B and An, Q and Guo, JS},
title = {Acceleration of biofilm formation in start-up of sequencing batch biofilm reactor using carriers immobilized with Pseudomonas stutzeri strain XL-2.},
journal = {Bioresource technology},
volume = {314},
number = {},
pages = {123736},
doi = {10.1016/j.biortech.2020.123736},
pmid = {32619807},
issn = {1873-2976},
abstract = {P. stutzeri strain XL-2 initially immobilized on polypropylene carriers accelerated the biofilm formation in start-up of sequencing batch biofilm reactor (SBBR) (denoted R1). The biofilm formation in R1 was approximately completed in 36 days, which was shorter than that of 48 days in an identical SBBR (denoted R2) without strain XL-2. Meanwhile, R1 presented a rapid stabilization of NH4+-N and TN removal to 81.7% and 72.4% respectively. Surface plasmon resonance demonstrated that strain XL-2 enhanced the initial adhesion of carrier surface due to the production of extracellular polymeric substances (EPS), which made it easier for other EPS-producing strains, such as Thauera and Flavobacterium, to adhere to the carriers. PICRUSt revealed that biofilm in R1 presented relatively higher activity of EPS biosynthesis enzymes (glycosyltransferase and asparagine synthase). Thus, high EPS content was obtained due to the application of carriers immobilized with strain XL-2 and finally promoted the biofilm formation.},
}
@article {pmid32619353,
year = {2020},
author = {Cordeiro, RA and de Andrade, ARC and Portela, FVM and Pereira, LMG and Moura, SGB and Sampaio, MD and Pereira, EMA and de Melo Guedes, GM and Bandeira, SP and de Lima-Neto, RG and Melo, VMM and Brilhante, RSN and Castelo-Branco, DSCM and Rocha, MFG and Sidrim, JJC},
title = {Proposal for a microcosm biofilm model for the study of vulvovaginal candidiasis.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-11},
doi = {10.1080/08927014.2020.1785435},
pmid = {32619353},
issn = {1029-2454},
abstract = {This study proposes a microcosm biofilm (MiB) model for the study of vulvovaginal candidiasis (VVC). Different conditions that mimic the vaginal environment were tested for MiB formation. The best growth conditions were obtained with samples incubated in vaginal fluid simulator medium pH 4.5 at 35 °C under a microaerophilic atmosphere. MiBs were evaluated for growth kinetics, fluconazole susceptibility and morphology. Samples containing high numbers of bacteria were analyzed for metagenomics. At 48 h, MiBs presented a higher cell density (CFU ml-1), a higher biomass and tolerance to fluconazole than their corresponding monospecies biofilms. Morphological analysis of MiBs revealed blastoconidia preferentially adhered to epithelial cells. Abundant Lactobacillus spp. were detected in two clinical samples; their MiBs showed a lower biomass and a higher fluconazole susceptibility. The proposed model proved to be a useful tool for the study of the complex microbial relationship in the vaginal environment, and may help to find new strategies for VVC control.},
}
@article {pmid32619289,
year = {2020},
author = {Wu, Z and Zheng, R and Zhang, J and Wu, S},
title = {Transcriptional profiling of Pseudomonas aeruginosa PAO1 in response to anti-biofilm and anti-infection agent exopolysaccharide EPS273.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14764},
pmid = {32619289},
issn = {1365-2672},
abstract = {AIMS: Relative few anti-biofilm polysaccharides against Pseudomonas aeruginosa were done to investigate the underlying molecular mechanism. Exopolysaccharide EPS273 can clearly reduce biofilm formation and infection of P. aeruginosa. This study aims to investigate its anti-biofilm and anti-infection mechanism on transcriptional level.<br><br>METHODS AND RESULTS: Herein we used an RNA-Seq transcriptomic approach to investigate the underlying anti-biofilm and anti-infection mechanism of EPS273. The expression levels of a large number of genes were changed after P. aeruginosa PAO1 was treated with EPS273. Especially, the genes related to biofilm formation, such as gene involved in production of extracellular matrix and virulence factor, genes involved in flagella and cell motility and genes involved in iron acquisition. Notably, the expression levels of genes involved in regulatory and signal transduction were markedly downregulated, such as two-component system PhoP-PhoQ and quorum sensing (QS) system LasI/ LasR and RhlI/ RhlR. Furthermore, when gene phoP and phoQ was disrupted respectively, the reduction of biofilm formation and cell motility in mutant △phoP or △phoQ was also detected.<br><br>CONCLUSION: EPS273 may exert its anti-biofilm and anti-infection function by downregulating gene expression of two-component system PhoP-PhoQ and QS systems LasI/ LasR and RhlI/ RhlR of P. aeruginosa, which further regulated expression of genes involved in biofilm formation.<br><br>Our data will expand understanding of anti-biofilm mechanisms of polysaccharides on transcriptomic level.},
}
@article {pmid32619153,
year = {2020},
author = {da Silva, ACB and Sardi, JCO and de Oliveira, DGL and de Oliveira, CFR and Dos Santos, HF and Dos Santos, EL and Crusca, E and Cardoso, MH and Franco, OL and Macedo, MLR},
title = {Development of a novel anti-biofilm peptide derived from profilin of Spodoptera frugiperda.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-11},
doi = {10.1080/08927014.2020.1776857},
pmid = {32619153},
issn = {1029-2454},
abstract = {Candida yeast infections are the fourth leading cause of death worldwide. Peptides with antimicrobial activity are a promising alternative treatment for such infections. Here, the antifungal activity of a new antimicrobial peptide-PEP-IA18-was evaluated against Candida species. PEP-IA18 was designed from the primary sequence of profilin, a protein from Spodoptera frugiperda, and displayed potent activity against Candida albicans and Candida tropicalis, showing a minimum inhibitory concentration (MIC) of 2.5 µM. Furthermore, the mechanism of action of PEP-IA18 involved interaction with the cell membrane (ergosterol complexation). Treatment at MIC and/or 10 × MIC significantly reduced biofilm formation and viability. PEP-IA18 showed low toxicity toward human fibroblasts and only revealed hemolytic activity at high concentrations. Thus, PEP-IA18 exhibited antifungal and anti-biofilm properties with potential applicability in the treatment of infections caused by Candida species.},
}
@article {pmid32616121,
year = {2020},
author = {Liu, Y and Zeng, R and Duan, Z and Xu, H and Wu, Q and Chen, Q and Lin, T and Li, M},
title = {[Effect of 5-aminolevulinic Acid Photodynamics Therapy on Biofilm of Propionibacterium Acnes].},
journal = {Zhongguo yi xue ke xue yuan xue bao. Acta Academiae Medicinae Sinicae},
volume = {42},
number = {3},
pages = {283-288},
doi = {10.3881/j.issn.1000-503X.11774},
pmid = {32616121},
issn = {1000-503X},
abstract = {Objective To investigate the effect of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) on Propionibacterium acnes (P.acnes) biofilm. MethodsP.acnes biofilms were constructed on a cell slide and treated with ALA-PDT.According to different light doses,the biofilms were divided into six groups:ALA-PDT group [ALA-PDT1 (50 J/cm2),ALA-PDT2 group (100 J/cm2),ALA-PDT3 group (200 J/cm2)],ALA-only group (ALA group),light-only group (LED),and a negative control group (ALA-PDT-group).The biofilm structure and the ratio of the dead bacteria/live bacteria were observed using a laser confocal microscope (CLSM).Biofilm viability was measured using the XTT assay. Results CLSM showed that the biofilm structures of ALA group and LED group were not significantly different from that of ALA-PDT-group,whereas the biofilm structure was more seriously damaged in ALA-PDT1 group,ALA-PDT2 group,and ALA-PDT3 group than in the ALA-PDT-group.The ratios of the dead/live bacteria in ALA-PDT-group,ALA group,LED group,ALA-PDT1 group,ALA-PDT2 group,and ALA-PDT3 group were 0.350±0.033, 0.305±0.046, 0.330±0.032, 1.525±0.439, 2.293±0.148 and 3.092±0.189,respectively.ALA group(md=0.003, P=1.000)and LED group(md=-0.025, P=1.000)did not significantly differ from the ALA-PDT-group.However,the ratio of dead/live bacteria in ALA-PDT-group was significantly lower than those in ALA-PDT1 group (md=-0.162, P<0.001),ALA-PDT2 group (md=-0.254, P<0.001),and ALA-PDT3 group (md=-0.352, P<0.001).The values of the XTT assay were were 0.462±0.028,0.465±0.044,0.437±0.047,0.301±0.040,0.207±0.001,and 0.110±0.007,respectively,in ALA-PDT-group,ALA group,LED group,ALA-PDT1 group,ALA-PDT2 group,and ALA-PDT3 group.Although the values of XTT assay in ALA(md=-0.044, P=1.000)and LED groups (md=-0.020, P=1.000)did not significantly differ from that in ALA-PDT-group,it was significantly higher in ALA-PDT-group than in ALA-PDT1 group (md=1.175, P<0.001),ALA-PDT2 group (md=1.942, P<0.001),and ALA-PDT3 group (md=-0.352, md=2.742, P<0.001). Conclusions ALA-PDT has an inhibitory effect on P.acnes biofilm.ALA-PDT destroys biofilm structure and inhibits biofilm viability.},
}
@article {pmid32615520,
year = {2020},
author = {Chaves, S and Longo, M and Gómez López, A and Del V Loto, F and Mechetti, M and Romero, CM},
title = {Control of microbial biofilm formation as an approach for biomaterials synthesis.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {194},
number = {},
pages = {111201},
doi = {10.1016/j.colsurfb.2020.111201},
pmid = {32615520},
issn = {1873-4367},
abstract = {The search for new biomaterials with superior mechanical properties is the focus in the area of materials science. A promising pathway is drawing inspiration from nature to design and develop materials with enhanced properties. In this work, a novel strategy to produce functionalized supramolecular bionanomaterials from the microbial biofilm is reported. Tuneable biofilms with specific characteristics were obtained by controlling the culture condition of the microorganism. When the exopolysaccharide (EPS) production was desired the tryptone was the best nutritional component for the EPS production into the biofilm. However, for the expression of a high amount of amyloid protein the combination of peptone and glucose was the best nutritional choice. Each biofilm obtained showed its owner rheology properties. These properties were altered by the addition of extracellular DNA, which increased the viscosity of the biofilm and induced a viscoelastic hydrogel behavior. Besides, as a proof of concept of bionanomaterial, a novel supramolecular polymeric hybrid EPS-Amyloid protein (EPAP) was obtained from the biofilm and it was tested as a new natural functionalized support for enzyme immobilization. The results suggest that this technology could be used as a new concept to obtain biomaterials from biofilms by controlling the nutritional conditions of a microorganism. Understanding environmental factors affecting biofilm formation will help the development of methods for controlling biofilm production and therefore obtaining new biomaterials.},
}
@article {pmid32614918,
year = {2020},
author = {Moussa, DG and Aparicio, C},
title = {Targeting the oral plaque microbiome with immobilized anti-biofilm peptides at tooth-restoration interfaces.},
journal = {PloS one},
volume = {15},
number = {7},
pages = {e0235283},
doi = {10.1371/journal.pone.0235283},
pmid = {32614918},
issn = {1932-6203},
abstract = {Recurrent caries, the development of carious lesions at the interface between the restorative material and the tooth structure, is highly prevalent and represents the primary cause for failure of dental restorations. Correspondingly, we exploited the self-assembly and strong antibiofilm activity of amphipathic antimicrobial peptides (AAMPs) to form novel coatings on dentin that aimed to prevent recurrent caries at susceptible cavosurface margins. AAMPs are alternative to traditional antimicrobial agents and antibiotics with the ability to target the complex and heterogeneous organization of microbial communities. Unlike approaches that have focused on using these AAMPs in aqueous solutions for a transient activity, here we assess the effects on microcosm biofilms of a long-acting AAMPs-based antibiofilm coating to protect the tooth-composite interface. Genomewise, we studied the impact of AAMPs coatings on the dental plaque microbial community. We found that non-native all D-amino acids AAMPs coatings induced a marked shift in the plaque community and selectively targeted three primary acidogenic colonizers, including the most common taxa around Class II composite restorations. Accordingly, we investigated the translational potential of our antibiofilm dentin using multiphoton pulsed near infra-red laser for deep bioimaging to assess the impact of AAMPs-coated dentin on plaque biofilms along dentin-composite interfaces. Multiphoton enabled us to record the antibiofilm potency of AAMPs-coated dentin on plaque biofilms throughout exaggeratedly failed interfaces. In conclusion, AAMPs-coatings on dentin showed selective and long-acting antibiofilm activity against three dominant acidogenic colonizers and potential to resist recurrent caries to promote and sustain the interfacial integrity of adhesive-based interfaces.},
}
@article {pmid32612893,
year = {2020},
author = {Dosler, S and Hacioglu, M and Yilmaz, FN and Oyardi, O},
title = {Biofilm modelling on the contact lenses and comparison of the in vitro activities of multipurpose lens solutions and antibiotics.},
journal = {PeerJ},
volume = {8},
number = {},
pages = {e9419},
pmid = {32612893},
issn = {2167-8359},
abstract = {During the contact lens (CL) usage, microbial adhesion and biofilm formation are crucial threats for eye health due to the development of mature biofilms on CL surfaces associated with serious eye infections such as keratitis. For CL related eye infections, multi drug resistant Pseudomonas aeruginosa or Staphylococcus aureus (especially MRSA) and Candida albicans are the most common infectious bacteria and yeast, respectively. In this study, CL biofilm models were created by comparing them to reveal the differences on specific conditions. Then the anti-biofilm activities of some commercially available multipurpose CL solutions (MPSs) and antibiotic eye drops against mature biofilms of S. aureus, P. aeruginosa, and C. albicans standard and clinical strains were determined by the time killing curve (TKC) method at 6, 24 and 48 h. According to the biofilm formation models, the optimal biofilms occurred in a mixture of bovine serum albumin (20% v/v) and lysozyme (2 g/L) diluted in PBS at 37 °C for 24 h, without shaking. When we compared the CL types under the same conditions, the strongest biofilms according to their cell density, were formed on Pure Vision ≥ Softens 38 > Acuve 2 ∼ Softens Toric CLs. When we compared the used CLs with the new ones, a significant increase at the density of biofilms on the used CLs was observed. The most active MPS against P. aeruginosa and S. aureus biofilms at 24 h was Opti-Free followed by Bio-True and Renu according to the TKC analyses. In addition, the most active MPS against C. albicans was Renu followed by Opti-Free and Bio-True at 48 h. None of the MPSs showed 3 Log bactericidal/fungicidal activity, except for Opti-Free against S. aureus and P. aeruginosa biofilms during 6 h contact time. Moreover, all studied antibiotic eye drops were active against S. aureus and P. aeruginosa biofilms on CLs at 6 h and 24 h either directly or as 1/10 concentration, respectively. According to the results of the study, anti-biofilm activities of MPSs have changed depending on the chemical ingredients and contact times of MPSs, the type of infectious agent, and especially the CL type and usage time.},
}
@article {pmid32612729,
year = {2020},
author = {Li, T and Zhang, Z and Wang, F and He, Y and Zong, X and Bai, H and Liu, Z},
title = {Antimicrobial Susceptibility Testing of Metronidazole and Clindamycin against Gardnerella vaginalis in Planktonic and Biofilm Formation.},
journal = {The Canadian journal of infectious diseases &amp; medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale},
volume = {2020},
number = {},
pages = {1361825},
pmid = {32612729},
issn = {1712-9532},
abstract = {Background: Bacterial vaginosis (BV), one of the most common vaginal ecosystem-related microbiologic syndromes, is the most common disorder in women of reproductive age. Gardnerella (G.) vaginalis is the predominant species causing this infection. Our aim was to compare the antimicrobial susceptibilities of metronidazole and clindamycin against G. vaginalis at planktonic and biofilm levels.<br><br>Methods: From September 2019 to October 2019, we recruited a total of 10 patients with BV who underwent gynecological examinations at Beijing Obstetrics and Gynecology Hospital. G. vaginalis isolates were obtained from the vagina and identified using their characteristic colony morphology. Sequence data of clinical G. vaginalis isolates were confirmed by comparing 16S rDNA sequences. Subsequently, clinical isolates were evaluated for antimicrobial susceptibilities in vitro to metronidazole and clindamycin at planktonic and biofilm levels. The minimum inhibitory concentration (MIC) for metronidazole and clindamycin was evaluated by antimicrobial susceptibility testing. The minimum biofilm eradication concentration (MBEC) was evaluated by the biofilm inhibition assay.<br><br>Results: Planktonic clinical isolates showed a significantly higher susceptibility rate (76.67%) and lower resistance rate (23.33%) to clindamycin than to metronidazole (susceptibility rate: 38.24%; resistance rate: 58.82%; P < 0.05 for both). Furthermore, in comparison to planktonic isolates, the minimum inhibitory concentration (MIC) of metronidazole was significantly higher for biofilm-forming isolates (7.3 ± 2.6 μg/mL vs. 72.4 ± 18.3 μg/mL; P=0.005); the resistance rate was 27.3%, and the minimum biofilm eradication concentration (MBEC) was >128 μg/mL. Moreover, the MIC of clindamycin was higher too for biofilm-forming isolates (0.099 ± 0.041 μg/mL vs. 23.7 ± 9.49 μg/mL; P=0.034); the resistance rate was 27.3%, and the MBEC of clindamycin was 28.4 ± 6.50 μg/mL.<br><br>Conclusion: Our results indicate that in comparison to metronidazole, clindamycin seems to be a better choice to tackle G. vaginalis as it exhibits a relatively higher susceptibility rate and lower resistance rate.},
}
@article {pmid32610234,
year = {2020},
author = {Zhuang, Z and Yang, G and Mai, Q and Guo, J and Liu, X and Zhuang, L},
title = {Physiological potential of extracellular polysaccharide in promoting Geobacter biofilm formation and extracellular electron transfer.},
journal = {The Science of the total environment},
volume = {741},
number = {},
pages = {140365},
doi = {10.1016/j.scitotenv.2020.140365},
pmid = {32610234},
issn = {1879-1026},
abstract = {Geobacter sulfurreducens biofilms have promising applications in renewable energy, pollutant bioremediation, and bioelectronic applications. Genetically manipulating G. sulfurreducens biofilms is an effective strategy to improve the capacity of extracellular electron transfer (EET). Extracellular polysaccharide, a sticky component surrounding microbes, plays an important role in EET. Herein, we constructed a mutant of G. sulfurreducens strain PCA overexpressing the gene GSU1501 (part of the ATP-dependent exporter of the polysaccharide biosynthesis gene operon), designated strain PCA-1501, to increase EET capacity. Experimental results showed that the overexpression of GSU1501 increased extracellular polysaccharide secretion by 25.5%, which promoted the formation of biofilm with higher thickness and viability, as well as the content of extracellular c-type cytochromes. Compared with the control strain, the mutant showed a higher capacity of Fe(III) oxide reduction and current generation (increased by 20.4% and 22.2%, respectively). Interestingly, the overexpression of GSU1501 hindered the pili formation by reducing the transcription level of pilA; a compensatory relationship between extracellular polysaccharide and pili in promoting biofilm formation deserves further investigation. This study provides a feasible method to promote the EET capacity of G. sulfurreducens biofilms, which benefit their bioelectrochemical applications.},
}
@article {pmid32609185,
year = {2020},
author = {Jain, A and Armstrong, SR and Banas, JA and Qian, F and Maia, RR and Teixeira, EC},
title = {Dental adhesive microtensile bond strength following a biofilm-based in vitro aging model.},
journal = {Journal of applied oral science : revista FOB},
volume = {28},
number = {},
pages = {e20190737},
doi = {10.1590/1678-7757-2019-0737},
pmid = {32609185},
issn = {1678-7765},
abstract = {OBJECTIVE: Laboratory tests are routinely used to test bonding properties of dental adhesives. Various aging methods that simulate the oral environment are used to complement these tests for assessment of adhesive bond durability. However, most of these methods challenge hydrolytic and mechanical stability of the adhesive- enamel/dentin interface, and not the biostability of dental adhesives. To compare resin-dentin microtensile bond strength (μTBS) after a 15-day Streptococcus mutans (SM) or Streptococcus sobrinus (SS) bacterial exposure to the 6-month water storage (WS) ISO 11405 type 3 test.<br><br>METHODOLOGY: A total of 31 molars were flattened and their exposed dentin was restored with Optibond-FL adhesive system and Z-100 dental composite. Each restored molar was sectioned and trimmed into four dumbbell-shaped specimens, and randomly distributed based on the following aging conditions: A) 6 months of WS (n=31), B) 5.5 months of WS + 15 days of a SM-biofilm challenge (n=31), C) 15 days of a SM-biofilm challenge (n=31) and D) 15 days of a SS-biofilm challenge (n=31). μTBS were determined and the failure modes were classified using light microscopy.<br><br>RESULTS: Statistical analyses showed that each type of aging condition affected μTBS (p<0.0001). For Group A (49.7±15.5MPa), the mean μTBS was significantly greater than in Groups B (19.3±6.3MPa), C (19.9±5.9MPa) and D (23.6±7.9MPa). For Group D, the mean μTBS was also significantly greater than for Groups B and C, but no difference was observed between Groups B and C.<br><br>CONCLUSION: A Streptococcus mutans- or Streptococcus sobrinus-based biofilm challenge for 15 days resulted in a significantly lower μTBS than did the ISO 11405 recommended 6 months of water storage. This type of biofilm-based aging model seems to be a practical method for testing biostability of resin-dentin bonding.},
}
@article {pmid32608853,
year = {2020},
author = {Qin, JW and Xin, X and Lu, H and Zhang, PP and Wang, LR and Zou, CW and Guo, JY},
title = {[Bacterial Community Shifts and Nitrogen Removal Characteristics for a SNAD Process Treating Anaerobic Digester Liquor of Swine Wastewater (ADLSW) in a Continuous-Flow Biofilm Reactor (CFBR)].},
journal = {Huan jing ke xue= Huanjing kexue},
volume = {41},
number = {5},
pages = {2349-2357},
doi = {10.13227/j.hjkx.201910018},
pmid = {32608853},
issn = {0250-3301},
abstract = {To realize a simultaneous partial nitrification, ANAMMOX (anaerobic ammonium oxidation), and denitrification (SNAD) process treating anaerobic digester liquor of swine wastewater (ADLSW) in a continuous-flow biofilm reactor (CFBR), we first gradually increased the influent ammonium (NH4+-N) concentration, and then enhanced the ADLSW ratio in the influent during operation; dissolved oxygen (DO) was controlled at (0.4±0.1) mg·L-1 by adjusting the air flow rate, and the temperature was kept at (30±1)℃. Meanwhile, high-throughput sequencing and quantitative PCR (polymerase chain reaction) techniques were used to analyze the bacterial community shifts and the amount of dominant nitrogen removal bacteria. The results demonstrated that a successful start-up of the SNAD process was accomplished in 150 d, and replacement of the actual biogas slurry was completed in 298 d. The effluent (NO3--N+NO2--N)/ΔNH4+-N value was less than 0.11, and the average removal rates of NH4+-N and TN (total nitrogen) increased to 63.26% and 55.71%, respectively. Moreover, high-throughput sequencing results demonstrated that the dominant microbial populations at phylum level were Chloroflexi (with a relative abundance of 50.78%), Proteobacteria (13.34%), and Planctomycetes (9.26%). The relative abundance of Nitrosomonas increased from 1.55% to 1.98%. In addition, the relative abundance of Candidatus_Brocadia and Candidatus_Kuenenia increased from 0.01% and (<0.01%) to 4.66% and 4.18%, respectively, and the relative abundance of Denitratisoma increased from (<0.01%) to 2.06%. Meanwhile, qPCR analysis showed that the amounts of ammonia-oxidizing bacteria, ANAMMOX, and denitrifying bacteria increased significantly compared with the inoculated sludge. An efficient and stable nitrogen removal rate can be achieved, and the follow-up processing cost can be reduced, by application of the SNAD treatment process for ADLSW.},
}
@article {pmid32608741,
year = {2020},
author = {Zhao, ZR and Zhang, JY and Li, D and Li, FH},
title = {[Purification Characteristics of Urban Tail Water from Sewage Treatment Plant by Biofilm Ecological Floating Bed].},
journal = {Huan jing ke xue= Huanjing kexue},
volume = {41},
number = {2},
pages = {809-814},
doi = {10.13227/j.hjkx.201905150},
pmid = {32608741},
issn = {0250-3301},
abstract = {The purification characteristics of nitrogenous tail water were investigated using a biofilm ecological floating bed technology to study biofilm length, hydraulic retention time (HRT), and biofilm coverage area with the aim to explore the purification characteristics of biofilm on urban tail water. Results show that the removal rates of NH4+-N, NO3--N, and TN were 90.82%, 62.7%, and 81.96%, respectively, at the half water depth to the suspended biofilm. The removal rate of NH4+-N was only 22.07%, and the concentration changes of NO3--N and TN were not obvious throughout the whole water depth to the suspended biofilm. When the HRT was 6 days, the removal rates of NH4+-N and TN could reach 82.01% and 62.88%, respectively, whereas the lowest rates were 55.24% and 46.82%, respectively. When the HRT was 12 days, the removal rates of NH4+-N and TN reached up to 81.4% and 79.93%, respectively, whereas the lowest rates were 8.73% and 17.23%, respectively. In contrast, the nitrogen removal efficiency was high and stable when the HRT was 6 days. When the coverage area was 10%, the removal rate was decreased in one operation cycle. When the coverage area was 20%, the removal rate showed an upward trend. Under the conditions of 10% and 20% biofilm coverage area, the removal rates of TN were 62.88% and 71.09%, respectively.},
}
@article {pmid32608190,
year = {2020},
author = {Ho, MH and Hasturk, H and Young, DF and Xie, H},
title = {In vivo and ex vivo actions of a novel P. gingivalis inhibitor on multi-species biofilm, inflammatory response and periodontal bone loss.},
journal = {Molecular oral microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/omi.12305},
pmid = {32608190},
issn = {2041-1014},
abstract = {Chronic periodontitis is one of the most common infectious inflammatory diseases worldwide. Current therapeutic options for the disease are only partially and temporarily successful due to periodontal re-emergence of pathogens such as Porphyromonas gingivalis, a keystone bacterium in the oral microbial communities, which elicits a dysbiosis between the microbiota and the host. Previously, we reported a peptide inhibitor of P. gingivalis (SAPP) that specifically targets P. gingivalis and reduces its virulence potential in vitro. Here, we show that SAPP can modulate the ability of P. gingivalis to suppress the host innate immune system. Using a cytokine array analysis, we found that the levels of several cytokines including IL-6, IL-8, and MCP-1 in the culture media of human oral keratinocytes (HOKs) were significantly diminished in the presence of P. gingivalis. Whereas the levels of these cytokines were restored, at least partially, in the culture media of HOKs by SAPP treatment. Furthermore, we also observed in an ex-vivo assay that SAPP efficiently inhibited biofilm primed formation by mixed species oral bacteria, and significantly dampened the abnormally innate immune responses induced by these bacteria. We also demonstrated, using a mouse model, that SAPP could prevent alveolar bone loss induced by P. gingivalis. Our results suggest that SAPP specifically targets P. gingivalis and its associated bacterial communities and could be envisioned as an emerging therapy for periodontitis.},
}
@article {pmid32607723,
year = {2020},
author = {Ueda, A and Ogasawara, S and Horiuchi, K},
title = {Identification of the genes controlling biofilm formation in the plant commensal Pseudomonas protegens Pf-5.},
journal = {Archives of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00203-020-01966-0},
pmid = {32607723},
issn = {1432-072X},
support = {16KT0150//Japan Society for the Promotion of Science/ ; },
abstract = {Determinant genes controlling biofilm formation in a plant commensal bacterium, Pseudomonas protegens Pf-5, were identified by transposon mutagenesis. Comprehensive screening of 7500 transposon-inserted mutants led to the isolation of four mutants exhibiting decreased and five mutants exhibiting increased biofilm formation. Mutations in the genes encoding MFS drug resistance transporter, LapA adhesive protein, RetS sensor histidine kinase/response regulator, and HecA adhesin/hemagglutinin led to decreased biofilm formation, indicating that these genes are necessary for biofilm formation in Pf-5. The mutants exhibiting increased biofilm formation had transposon insertions in the genes coding for an outer membrane protein, a GGDEF domain-containing protein, AraC transcriptional regulator, non-ribosomal peptide synthetase OfaB, and the intergenic region of a DNA-binding protein and the Aer aerotaxis receptor, suggesting that these genes are negative regulators of biofilm formation. Some of these mutants also showed altered swimming and swarming motilities, and a negative correlation between biofilm formation and swarming motility was observed. Thus, sessile-motile lifestyle is regulated by divergent regulatory genes in Pf-5.},
}
@article {pmid32606995,
year = {2020},
author = {Lamichhane, K and Adhikari, N and Bastola, A and Devkota, L and Bhandari, P and Dhungel, B and Thapa Shrestha, U and Adhikari, B and Banjara, MR and Rijal, KR and Ghimire, P},
title = {Biofilm-Producing Candida Species Causing Oropharyngeal Candidiasis in HIV Patients Attending Sukraraj Tropical and Infectious Diseases Hospital in Kathmandu, Nepal.},
journal = {HIV/AIDS (Auckland, N.Z.)},
volume = {12},
number = {},
pages = {211-220},
pmid = {32606995},
issn = {1179-1373},
abstract = {Introduction: Oropharyngeal candidiasis are the commonest fungal infections among HIV-positive patients. The main objective of this study was to explore biofilm-producing Candida species causing oropharyngeal infections among HIV patients attending Sukraraj Tropical and Infectious Diseases Hospital (STIDH) in Kathmandu, Nepal.<br><br>Methods: Oropharyngeal swabs were collected from the HIV-positive patients between July and December 2019. A total of 174 oropharyngeal swabs were cultured on Sabouraud Dextrose Agar (SDA). All samples were inoculated on SDA slants supplemented with chloramphenicol and underwent incubation at 37°C for 24-48 hours. Any visible growth reported was processed for the identification of the species. Candida species were differentiated based on the growth and colour of the isolates on CHROM agar candida. Biofilm production in Candida species was determined by the microtiter plate method (MPM). Antifungal susceptibility testing was performed using the disc diffusion method.<br><br>Results: Among 174 oropharyngeal samples, 23.6% (n=41/174) of them had oropharyngeal infections and 36.6% of the oropharyngeal infections (15/41) had CD4 T-lymphocytes count below 200 cells/mm3 who were also active tobacco users (p<0.05). Among Candidial growth, 61% (25/41) were Candida albicans and 39% (16/41) were non-albicans. Of 41 Candida spp., 65% (27/41) were biofilm producers. An equal proportion of Candida albicans (4 isolates) and non-albicans (4 isolates) were strong biofilm producers. C. albicans isolates were sensitive towards clotrimazole (96%; 24/25) and fluconazole (92%; 23/25), whereas sensitivity towards ketoconazole was only 48% (12/25). Non-albicans Candida was highly sensitive to amphotericin-B (62.5%; 10/16) followed by clotrimazole (56.2%; 9/16). The biofilm-producing Candida isolates showed the highest resistivity (51.9%; 14/27) to ketoconazole and lowest (22.2%; 6/27) to clotrimazole.<br><br>Conclusion: Oropharyngeal candidiasis is a common opportunistic infection among HIV-infected individuals. The majority of cases of oropharyngeal candidiasis are caused by biofilm producers Candida albicans and non-albicans Candida. Biofilm producers Candida were more resistant towards commonly used antifungal drugs.},
}
@article {pmid32606813,
year = {2020},
author = {Kashef, MT and Saleh, NM and Assar, NH and Ramadan, MA},
title = {The Antimicrobial Activity of Ciprofloxacin-Loaded Niosomes against Ciprofloxacin-Resistant and Biofilm-Forming Staphylococcus aureus.},
journal = {Infection and drug resistance},
volume = {13},
number = {},
pages = {1619-1629},
pmid = {32606813},
issn = {1178-6973},
abstract = {Purpose: The threat of Staphylococcus aureus antimicrobial resistance is increasing worldwide. Niosomes are a new drug delivery system that enhances the antimicrobial potential of antibiotics. We hereby aim to evaluate the antimicrobial and antibiofilm activity of ciprofloxacin-loaded niosomes.<br><br>Methods: The antimicrobial susceptibility of clinical S. aureus isolates (n=59) was determined by Kirby-Bauer disk diffusion method. Their biofilm formation activity was tested by Christensen's method. Two ciprofloxacin-loaded niosomal formulations were prepared by thin-film hydration method, and their minimum inhibitory concentrations (MIC) were determined by agar dilution method, against ciprofloxacin-resistant and biofilm-forming isolates (n=24). Their ability to inhibit biofilm formation and eradicate already formed biofilms was evaluated and further confirmed by scanning electron microscope images. Non-synonymous mutations, in a quinolone resistance-determining regions of S. aureus isolates, were detected by polymerase chain reaction.<br><br>Results: Most of the isolates were methicillin- (47/59) and ciprofloxacin-resistant (45/59). All except two isolates were capable of biofilm production. Niosomal preparation I reduced ciprofloxacin MIC by twofold in four isolates, whereas preparation II reduced ciprofloxacin MIC of most isolates by 8- to 32-fold, with three isolates that became ciprofloxacin-susceptible. Non-synonymous mutations were detected in isolates that maintained phenotypic ciprofloxacin resistance against ciprofloxacin-loaded niosomal preparation II. Ciprofloxacin-loaded niosomes reduced the minimum biofilm inhibitory concentration and the minimum biofilm eradication concentration in 58% and 62% of the tested isolates, respectively.<br><br>Conclusion: Ciprofloxacin-loaded niosomes can restore ciprofloxacin activity against resistant S. aureus isolates. To our knowledge, this is the first report on the inhibition of biofilm formation and eradication of formed biofilms by ciprofloxacin-loaded niosomes.},
}
@article {pmid32604791,
year = {2020},
author = {De Gregorio, E and Esposito, A and Vollaro, A and De Fenza, M and D'Alonzo, D and Migliaccio, A and Iula, VD and Zarrilli, R and Guaragna, A},
title = {N-Nonyloxypentyl-l-Deoxynojirimycin Inhibits Growth, Biofilm Formation and Virulence Factors Expression of Staphylococcus aureus.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {9},
number = {6},
pages = {},
doi = {10.3390/antibiotics9060362},
pmid = {32604791},
issn = {2079-6382},
support = {PRIN2017 (Grant 2017SFBFER)//Ministero dell'Istruzione, dell'Università e della Ricerca/ ; FFC #20/2019//Fondazione per la Ricerca sulla Fibrosi Cistica/ ; },
abstract = {Staphylococcus aureus is one of the major causes of hospital- and community-associated bacterial infections throughout the world, which are difficult to treat due to the rising number of drug-resistant strains. New molecules displaying potent activity against this bacterium are urgently needed. In this study, d- and l-deoxynojirimycin (DNJ) and a small library of their N-alkyl derivatives were screened against S. aureus ATCC 29213, with the aim to identify novel candidates with inhibitory potential. Among them, N-nonyloxypentyl-l-DNJ (l-NPDNJ) proved to be the most active compound against S. aureus ATCC 29213 and its clinical isolates, with the minimum inhibitory concentration (MIC) value of 128 μg/mL. l-NPDNJ also displayed an additive effect with gentamicin and oxacillin against the gentamicin- and methicillin-resistant S. aureus isolate 00717. Sub-MIC values of l-NPDNJ affected S. aureus biofilm development in a dose-dependent manner, inducing a strong reduction in biofilm biomass. Moreover, real-time reverse transcriptase PCR analysis revealed that l-NPDNJ effectively inhibited at sub-MIC values the transcription of the spa, hla, hlb and sea virulence genes, as well as the agrA and saeR response regulator genes.},
}
@article {pmid32603591,
year = {2020},
author = {Locke, L and Shankaran, K and Gong, L and Stoodley, P and Vozar, SL and Cole, SL and Tweedle, MF and Wozniak, DJ},
title = {Evaluation of peptide-based probes towards in vivo diagnostic imaging of bacterial biofilm-associated infections.},
journal = {ACS infectious diseases},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsinfecdis.0c00125},
pmid = {32603591},
issn = {2373-8227},
abstract = {The clinical management of bacterial biofilm infections represents an enormous challenge in today's healthcare setting. The NIH estimates that 65% of bacterial infections are biofilm related and therapeutic outcomes are positively correlated with early intervention. Currently, there is no reliable imaging technique to detect biofilm infections in vivo and current clinical protocols for accurate and direct biofilm identification are non-existent. In orthopedic implant-associated biofilm infections, for example, current detection methods are based on non-specific X-ray or radiolabeled white blood cell imaging, coupled with peri-prosthetic tissue or fluid samples taken invasively and must be cultured. This approach is time consuming and often fails to detect biofilm bacteria due to sampling errors and lack of sensitivity. The ability to quantify bacterial biofilms by real-time, non-invasive imaging is an urgent, unmet clinical need that would revolutionize the management and treatment of these devastating types of infections. In the present study, we assembled a collection of fluorescently labeled peptide candidates to specifically explore their biofilm targeting properties. We evaluated these fluorescently labeled peptides using various in vitro assays for their ability to specifically and non-destructively target biofilms produced by the model bacterial pathogen Pseudomonas aeruginosa. The lead candidate that emerged, 4Iphf-HN17, demonstrated rapid biofilm labeling kinetics, a lack of bactericidal activity, and biofilm targeting specificity in human cell infection models. In vivo, fluorescently labeled 4Iphf-HN17 showed enhanced accumulation in biofilm-infected wounds, thus warranting further study.},
}
@article {pmid32603487,
year = {2020},
author = {Ohn, HM and Mizuno, T and Sudo, Y and Miyoshi, SI},
title = {Interaction of Escherichia coli and its culture supernatant with Vibrio vulnificus during biofilm formation.},
journal = {Microbiology and immunology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1348-0421.12829},
pmid = {32603487},
issn = {1348-0421},
abstract = {Vibrio vulnificus is a foodborne pathogen causing septicemia with high mortality rate. In this study, we explored how Escherichia coli, one of the commensal bacteria in human gastrointestinal tract, can interact with V. vulnificus. Our study showed that, the amount of biofilm produced by V. vulnificus was reduced in the presence of E. coli ATCC 35218, although the growth of V. vulnificus L-180 remains unaffected. We also detected antibiofilm effect of E. coli culture supernatant against V. vulnificus. But this effect could not be reduced even after heat treatment. These findings indicate that E. coli and its culture supernatant may be suitable to prevent the biofilm formation by V. vulnificus. On the other hand, V. vulnificus living cells could reduce the amount of preformed E. coli biofilm, however, its culture supernatant could not. This suggests that the cell-associated factors contribute towards reduction in the E. coli biofilm. Therefore, we speculate that ingestion of infectious dose of V. vulnificus might induce dislodging of the commensal bacteria from the intestinal epithelia and thus can colonize to initiate the infection. This article is protected by copyright. All rights reserved.},
}
@article {pmid32601062,
year = {2020},
author = {Marmont, LS and Whitfield, GB and Pfoh, R and Williams, RJ and Randall, TE and Ostaszewski, A and Razvi, E and Groves, RA and Robinson, H and Nitz, M and Parsek, MR and Lewis, IA and Whitney, JC and Harrison, J and Howell, PL},
title = {PelX is a UDP-N-acetylglucosamine C4-epimerase involved in Pel polysaccharide-dependent biofilm formation.},
journal = {The Journal of biological chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1074/jbc.RA120.014555},
pmid = {32601062},
issn = {1083-351X},
abstract = {Pel is an N-acetylgalactosamine-rich bacterial polysaccharide that contributes to the structure and function of Pseudomonas aeruginosa biofilms. The pelABCDEFG operon is highly conserved among diverse bacterial species, and Pel may therefore be a widespread biofilm determinant. Previous annotation of pel gene clusters has helped us identify an additional gene, pelX, that is present adjacent to pelABCDEFG in >100 different bacterial species. The pelX gene is predicted to encode a member of the short-chain dehydrogenase/reductase (SDR) superfamily, but its potential role in Pel-dependent biofilm formation is unknown. Herein, we have used Pseudomonas protegens Pf-5 as a model to elucidate PelX function as P. aeruginosa lacks a pelX homologue in its pel gene cluster. We found that P. protegens forms Pel-dependent biofilms; however, despite expression of pelX under these conditions, biofilm formation was unaffected in a ΔpelX strain. This observation led us to identify a pelX paralog, PFL_5533, which we designate here PgnE, that appears to be functionally redundant to pelX In line with this, a ΔpelX ΔpgnE double mutant was substantially impaired in its ability to form Pel-dependent biofilms. To understand the molecular basis for this observation, we determined the structure of PelX to 2.1 Å resolution. The structure revealed that PelX resembles UDP-N-acetylglucosamine (UDP-GlcNAc) C4-epimerases. Using 1H NMR analysis, we show that PelX catalyzes the epimerization between UDP-GlcNAc and UDP-GalNAc. Our results indicate that Pel-dependent biofilm formation requires a UDP-GlcNAc C4-epimerase that generates the UDP-GalNAc precursors required by the Pel synthase machinery for polymer production.},
}
@article {pmid32600373,
year = {2020},
author = {Thorarinsdottir, HR and Kander, T and Holmberg, A and Petronis, S and Klarin, B},
title = {Biofilm formation on three different endotracheal tubes: a prospective clinical trial.},
journal = {Critical care (London, England)},
volume = {24},
number = {1},
pages = {382},
pmid = {32600373},
issn = {1466-609X},
support = {2012-01252//VINNOVA/ ; 814201//Skåne County Council's Research and Development Foundation/ ; },
abstract = {BACKGROUND: Biofilm formation on endotracheal tubes (ETTs) is an early and frequent event in mechanically ventilated patients. The biofilm is believed to act as a reservoir for infecting microorganisms and thereby contribute to development and relapses of ventilator-associated pneumonia (VAP). Once a biofilm has formed on an ETT surface, it is difficult to eradicate. This clinical study aimed to compare biofilm formation on three widely used ETTs with different surface properties and to explore factors potentially predictive of biofilm formation.<br><br>METHODS: We compared the grade of biofilm formation on ETTs made of uncoated polyvinyl chloride (PVC), silicone-coated PVC, and PVC coated with noble metals after > 24 h of mechanical ventilation in critically ill patients. The comparison was based on scanning electron microscopy of ETT surfaces, biofilm grading, surveillance and biofilm cultures, and occurrence of VAP.<br><br>RESULTS: High-grade (score ≥ 7) biofilm formation on the ETTs was associated with development of VAP (OR 4.17 [95% CI 1.14-15.3], p = 0.031). Compared to uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation (OR 0.18 [95% CI 0.06-0.59], p = 0.005, and OR 0.34 [95% CI 0.13-0.93], p = 0.036, respectively). No significant difference was observed between silicon-coated ETTs and noble-metal-coated ETTs (OR 0.54 [95% CI 0.17-1.65], p = 0.278). In 60% of the oropharyngeal cultures and 58% of the endotracheal cultures collected at intubation, the same microorganism was found in the ETT biofilm at extubation. In patients who developed VAP, the causative microbe remained in the biofilm in 56% of cases, despite appropriate antibiotic therapy. High-grade biofilm formation on ETTs was not predicted by either colonization with common VAP pathogens in surveillance cultures or duration of invasive ventilation.<br><br>CONCLUSION: High-grade biofilm formation on ETTs was associated with development of VAP. Compared to the uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation. Further research on methods to prevent, monitor, and manage biofilm occurrence is needed.<br><br>TRIAL REGISTRATION: ClinicalTrials.gov NCT02284438 . Retrospectively registered on 21 October 2014.},
}
@article {pmid32600259,
year = {2020},
author = {Loimaranta, V and Mazurel, D and Deng, D and Söderling, E},
title = {Xylitol and erythritol inhibit real-time biofilm formation of Streptococcus mutans.},
journal = {BMC microbiology},
volume = {20},
number = {1},
pages = {184},
pmid = {32600259},
issn = {1471-2180},
support = {11-2520//Turku University Foundation/ ; },
abstract = {BACKGROUND: Regular consumption of xylitol decreases the number of cariogenic streptococci in dental plaque. In vitro biofilm models to study the mechanism of xylitol action have been set-up, but the obtained results are contradictory. Biofilm growth is a dynamic process with time-specific characteristics that may remain undetected in conventional end-point biofilm tests. In this study we used an impedance spectroscopy instrument, xCELLigence Real Time Cell Analyzer (RTCA), that allows label-free, non-invasive real-time monitoring of biofilm formation, to explore effects of xylitol on biofilm formation by Streptococcus mutans. Based on the obtained information of biofilm dynamics, we assessed the number of viable bacteria, the polysaccharide content, and the expression levels of selected genes involved in glucan-mediated biofilm formation in different biofilm stages. Xylitol inhibition was compared with that of erythritol; another polyol suggested to have a positive impact on oral health.<br><br>RESULTS: Our results showed that real-time monitoring provided new information of polyol-induced changes in S. mutans biofilm formation dynamics. The inhibitory effect of polyols was more pronounced in the early stages of biofilm formation but affected also the measured total amount of formed biofilm. Effects seen in the real-time biofilm assay were only partially explained by changes in CFU values and polysaccharide amounts in the biofilms. Both xylitol and erythritol inhibited real-time biofilm formation by all the nine tested S. mutans strains. Sensitivity of the strains to inhibition varied: some were more sensitive to xylitol and some to erythritol. Xylitol also modified the expression levels of gbpB, gtfB, gtfC and gtfD genes that are important in polysaccharide-mediated adherence of S. mutans.<br><br>CONCLUSION: The erythritol- and xylitol- induced inhibition of biofilm formation was only partly explained by decrease in the number of viable S. mutans cells or the amount of polysaccharides in the biofilm matrix, suggesting that in addition to reduced proliferation also the matrix composition and thereby the surface attachment quality of biofilm matrix may be altered by the polyols.},
}
@article {pmid32600258,
year = {2020},
author = {Katongole, P and Nalubega, F and Florence, NC and Asiimwe, B and Andia, I},
title = {Biofilm formation, antimicrobial susceptibility and virulence genes of Uropathogenic Escherichia coli isolated from clinical isolates in Uganda.},
journal = {BMC infectious diseases},
volume = {20},
number = {1},
pages = {453},
pmid = {32600258},
issn = {1471-2334},
support = {107743//African Academy of Sciences/ ; },
abstract = {INTRODUCTION: Uropathogenic E. coli is the leading cause of Urinary tract infections (UTIs), contributing to 80-90% of all community-acquired and 30-50% of all hospital-acquired UTIs. Biofilm forming Uropathogenic E. coli are associated with persistent and chronic inflammation leading to complicated and or recurrent UTIs. Biofilms provide an environment for poor antibiotic penetration and horizontal transfer of virulence genes which favors the development of Multidrug-resistant organisms (MDRO). Understanding biofilm formation and antimicrobial resistance determinants of Uropathogenic E. coli strains will provide insight into the development of treatment options for biofilm-associated UTIs. The aim of this study was to determine the biofilm forming capability, presence of virulence genes and antimicrobial susceptibility pattern of Uropathogenic E. coli isolates in Uganda.<br><br>METHODS: This was a cross-sectional study carried in the Clinical Microbiology and Molecular biology laboratories at the Department of Medical Microbiology, Makerere University College of Health Sciences. We randomly selected 200 Uropathogenic E. coli clinical isolates among the stored isolates collected between January 2018 and December 2018 that had significant bacteriuria (> 105 CFU). All isolates were subjected to biofilm detection using the Congo Red Agar method and Antimicrobial susceptibility testing was performed using the Kirby disk diffusion method. The isolates were later subjected PCR for the detection of Urovirulence genes namely; Pap, Fim, Sfa, Afa, Hly and Cnf, using commercially designed primers.<br><br>RESULTS: In this study, 62.5% (125/200) were positive biofilm formers and 78% (156/200) of these were multi-drug resistant (MDR). The isolates were most resistant to Trimethoprim sulphamethoxazole and Amoxicillin (93%) followed by gentamycin (87%) and the least was imipenem (0.5%). Fim was the most prevalent Urovirulence gene (53.5%) followed by Pap (21%), Sfa (13%), Afa (8%), Cnf (5.5%) and Hyl (0%).<br><br>CONCLUSIONS: We demonstrate a high prevalence of biofilm-forming Uropathogenic E. coli strains that are highly associated with the MDR phenotype. We recommend routine surveillance of antimicrobial resistance and biofilm formation to understand the antibiotics suitable in the management of biofilm-associated UTIs.},
}
@article {pmid32599948,
year = {2020},
author = {Balaure, PC and Grumezescu, AM},
title = {Recent Advances in Surface Nanoengineering for Biofilm Prevention and Control. Part I: Molecular Basis of Biofilm Recalcitrance. Passive Anti-Biofouling Nanocoatings.},
journal = {Nanomaterials (Basel, Switzerland)},
volume = {10},
number = {6},
pages = {},
doi = {10.3390/nano10061230},
pmid = {32599948},
issn = {2079-4991},
abstract = {Medical device-associated infections are becoming a leading cause of morbidity and mortality worldwide, prompting researchers to find new, more effective ways to control the bacterial colonisation of surfaces and biofilm development. Bacteria in biofilms exhibit a set of &quot;emergent properties&quot;, meaning those properties that are not predictable from the study of free-living bacterial cells. The social coordinated behaviour in the biofilm lifestyle involves intricate signaling pathways and molecular mechanisms underlying the gain in resistance and tolerance (recalcitrance) towards antimicrobial agents as compared to free-floating bacteria. Nanotechnology provides powerful tools to disrupt the processes responsible for recalcitrance development in all stages of the biofilm life cycle. The present paper is a state-of-the-art review of the surface nanoengineering strategies currently used to design antibiofilm coatings. The review is structurally organised in two parts according to the targeted biofilm life cycle stages and molecular mechanisms intervening in recalcitrance development. Therefore, in the present first part, we begin with a presentation of the current knowledge of the molecular mechanisms responsible for increased recalcitrance that have to be disrupted. Further, we deal with passive surface nanoengineering strategies that aim to prevent bacterial cells from settling onto a biotic or abiotic surface. Both &quot;fouling-resistant&quot; and &quot;fouling release&quot; strategies are addressed as well as their synergic combination in a single unique nanoplatform.},
}
@article {pmid32599828,
year = {2020},
author = {Hathroubi, S and Zerebinski, J and Clarke, A and Ottemann, KM},
title = {Helicobacter pylori Biofilm Confers Antibiotic Tolerance in Part via A Protein-Dependent Mechanism.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {9},
number = {6},
pages = {},
doi = {10.3390/antibiotics9060355},
pmid = {32599828},
issn = {2079-6382},
support = {RO1AI116946//National Institute of Allergy and Infectious Diseases/ ; 1S10OD023528/NH/NIH HHS/United States ; },
abstract = {Helicobacter pylori, a WHO class I carcinogen, is one of the most successful human pathogens colonizing the stomach of over 4.4 billion of the world's population. Antibiotic therapy represents the best solution but poor response rates have hampered the elimination of H. pylori. A growing body of evidence suggests that H. pylori forms biofilms, but the role of this growth mode in infection remains elusive. Here, we demonstrate that H. pylori cells within a biofilm are tolerant to multiple antibiotics in a manner that depends partially on extracellular proteins. Biofilm-forming cells were tolerant to multiple antibiotics that target distinct pathways, including amoxicillin, clarithromycin, and tetracycline. Furthermore, this tolerance was significantly dampened following proteinase K treatment. These data suggest that H. pylori adapts its phenotype during biofilm growth resulting in decreased antibiotic susceptibility but this tolerance can be partially ameliorated by extracellular protease treatment.},
}
@article {pmid32599404,
year = {2020},
author = {Li, C and Gu, Z and Zhu, S and Liu, D},
title = {17β-Estradiol removal routes by moving bed biofilm reactors (MBBRs) under various C/N ratios.},
journal = {The Science of the total environment},
volume = {741},
number = {},
pages = {140381},
doi = {10.1016/j.scitotenv.2020.140381},
pmid = {32599404},
issn = {1879-1026},
abstract = {This study evaluated the contribution of biotic and abiotic routes to the 17β-estradiol (E2) removal in moving bed biofilm reactors (MBBRs), and uncovered the interrelation between the E2 removal routes and biofilm characteristics, which was not researched in previous literature. Three MBBRs with different C/N ratios (0 for C/N0; 2 for C/N2; and 5 for C/N5) were operated in continuous mode. A 65-day degradation demonstrated that the MBBRs had high potential to remove E2 regardless of the C/N (E2 removal greater than 99% for all MBBRs; P > 0.05). Further batch tests showed that the E2 removal mainly resulted from heterotrophic activities for all MBBRs, accounting for approximately 85% for all MBBRs (P > 0.05), followed by nitrification (10-11%) and adsorption (4-5%). Importantly, lower adhesive force likely led to higher E2 adsorption onto biofilms. Besides, enhanced ammonia oxidizing rate (AOR) was consistent with the high contribution of nitrification to the E2 attenuation. Importantly, heterotrophic activity was positively correlated with its contribution to E2 removal (r = 0.99, P < 0.05). To sum, the results obtained in this study helped to understand the E2 removal routes in nitrifying biofilm systems.},
}
@article {pmid32599380,
year = {2020},
author = {Tang, K and Ooi, GTH and Torresi, E and Kaarsholm, KMS and Hambly, A and Sundmark, K and Lindholst, S and Sund, C and Kragelund, C and Christensson, M and Bester, K and Andersen, HR},
title = {Municipal wastewater treatment targeting pharmaceuticals by a pilot-scale hybrid attached biofilm and activated sludge system (Hybas™).},
journal = {Chemosphere},
volume = {259},
number = {},
pages = {127397},
doi = {10.1016/j.chemosphere.2020.127397},
pmid = {32599380},
issn = {1879-1298},
abstract = {A hybrid wastewater treatment process with combined attached biofilm (moving bed biofilm reactor) and activated sludge, named as Hybas™, was implemented for the treatment of municipal wastewater. The system consisted of six staged reactors in series including pre-denitrification and nitrification in the Hybas™ line and post-denitrification in a pure MBBR. In addition to the significant removal of nutrients and organic matter from municipal wastewater, Hybas™ also showed removal capacity for pharmaceuticals. Of particular interest was the enhanced removal for pharmaceuticals (i.e. X-ray contrast media) compared to other biological systems. Spiking experiments showed that the maximum removal rate constants (k, h-1) for 10 out of the 21 investigated pharmaceuticals (including diclofenac) were observed to occur within the two aerobic Hybas ™ reactors, operated in a flow-shifting mode that allows even biofilm growth of nitrifying bacteria. In total, 14 out of the 21 pharmaceuticals were removed by more than 50% during continuous flow operation in the all Hybas™ line and post-denitrification MBBR. The calculated and estimated removal contributions of pharmaceuticals by each individual reactor were also assessed.},
}
@article {pmid32598252,
year = {2020},
author = {Ismail, NS and Subbiah, SK and Taib, NM},
title = {Application of Phenotype Microarray for Profiling Carbon Sources Utilization between Biofilm and Non-Biofilm of Clinical Isolates Pseudomonas aeruginosa.},
journal = {Current pharmaceutical biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.2174/1389201021666200629145217},
pmid = {32598252},
issn = {1873-4316},
abstract = {Pseudomonas aeruginosa a gram-negative bacterium with high versatility that can undergo aerobic and anaerobic respiration. Capabilities in deploying different carbon sources, energy metabolism, and regulatory system, ensure the survival of this microorganism in the diverse environmental conditions. Determination of differences in carbon sources utilization among biofilm and non-biofilm of P. aeruginosa provides a platform in understanding the metabolic activities of the microorganism. Three archived clinical isolates of strong, moderate, and non-biofilm producers were identified. ATCC 27853 P. aeruginosa was used as a negative control or non-biofilm producing microorganism. Biofilm formation of ATCC 27853 P. aeruginosa was confirmed by crystal violet assay (CVA) and Congo red agar (CRA). Metabolic profiles of the biofilm and non-biofilms isolates were determined by phenotype microarrays (Biolog Omnilog). In this study, the biofilm isolates utilized uridine, threonine, and serine while non-biofilm isolates utilized adenosine, inosine, monomethyl, sorbic acid, and succinamic acid. Sugar utilization was seen between the isolates adhering that biofilm P. aeruginosa preferred glucoside, galactoside, glucuronide, glucosaminide, mannoside, and galactosaminide, but it was not utilized by the non-biofilm. The outcome of this result can be used for future studies to improve detection or inhibition of the growth of clinical P. aeruginosa biofilm and non-biofilm, respectively.},
}
@article {pmid32596251,
year = {2020},
author = {Pettersson, S and Ahnoff, M and Edin, F and Lingström, P and Simark Mattsson, C and Andersson-Hall, U},
title = {A Hydrogel Drink With High Fructose Content Generates Higher Exogenous Carbohydrate Oxidation and Lower Dental Biofilm pH Compared to Two Other, Commercially Available, Carbohydrate Sports Drinks.},
journal = {Frontiers in nutrition},
volume = {7},
number = {},
pages = {88},
pmid = {32596251},
issn = {2296-861X},
abstract = {The purpose of this study was to evaluate the substrate oxidation of three commercially available, 14%-carbohydrate sports drinks with different compositions, osmolality, and pH for their impact on dental exposure to low pH. In a cross-over, randomized double-blinded design, 12 endurance athletes (age 31. 2 ± 7.7 years, V ˙ O2max 65.6 ± 5.0 mL·kg-1) completed 180 min of cycling at 55% Wmax. During the first 100 min of cycling, athletes consumed amylopectin starch (AP), maltodextrin+sucrose (MD+SUC), or maltodextrin+fructose hydrogel (MD+FRU) drinks providing 95 g carbohydrate·h-1, followed by water intake only at 120 and 160 min. Fuel use was determined using indirect calorimetry and stable-isotope techniques. Additionally, dental biofilm pH was measured using the microtouch method in a subsample of participants (n = 6) during resting conditions before, and at different time intervals up to 45 min following a single bolus of drink. Exogenous carbohydrate oxidation (CHOEXO) during the 2nd hour of exercise was significantly (P < 0.05) different between all three drinks: MD+FRU (1.17 ± 0.17 g·min-1), MD+SUC (1.01 ± 0.13 g·min-1), and AP (0.84 ± 0.11 g·min-1). At the end of exercise, CHOEXO and blood glucose concentrations (3.54 ± 0.50, 4.07 ± 0.67, and 4.28 ± 0.47 mmol·L-1, respectively) were significantly lower post MD+FRU consumption than post MD+SUC and AP consumption (P < 0.05). Biofilm acidogenicity at rest demonstrated a less pronounced pH fall for MD+FRU compared to the acidulant-containing MD+SUC and AP (P < 0.05). In conclusion, while total intake of MD+FRU showed signs of completed uptake before end of monitoring, this was less so for MD+SUC, and not at all the case for AP. Thus, this study showed that despite carbohydrates being encapsulated in a hydrogel, a higher CHOEXO was observed following MD+FRU drink ingestion compared to AP and MD+SUC consumption upon exposure to the acidic environment of the stomach. This finding may be related to the higher fructose content of the MD+FRU drink compared with the MD+SUC and AP drinks. Furthermore, a carbohydrate solution without added acidulants, which are commonly included in commercial sport drinks, may have less deleterious effects on oral health.},
}
@article {pmid32596125,
year = {2020},
author = {Hu, D and Zou, L and Yu, W and Jia, F and Han, H and Yao, K and Jin, Q and Ji, J},
title = {Relief of Biofilm Hypoxia Using an Oxygen Nanocarrier: A New Paradigm for Enhanced Antibiotic Therapy.},
journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)},
volume = {7},
number = {12},
pages = {2000398},
pmid = {32596125},
issn = {2198-3844},
abstract = {Biofilms are chief culprits of most intractable infections and pose great threats to human health. Conventional antibiotic therapies are hypodynamic to biofilms due to their strong drug resistance, closely related with biofilm hypoxia. A new strategy for enhanced antibiotic therapy by relieving biofilm hypoxia is reported here. A two-step sequential delivery strategy is fabricated using perfluorohexane (PFH)-loaded liposomes (lip) as oxygen (O2) carriers (denoted as lip@PFH@O2) and commercial antibiotics. The results indicate that the two-step sequential treatment exhibits much lower minimum bactericidal concentrations than the antibiotic treatment alone. In this design, the lip@PFH@O2 holds positively charged surface for better biofilm penetration. After penetrating into biofilm, oxygen can be released from lip@PFH@O2 by inches, which greatly relieves biofilm hypoxia. With the relief of hypoxia, the quorum sensing and the drug efflux pumps of bacteria are suppressed by restraining related gene expression, leading to the reduced antibiotic resistance. Furthermore, the in vivo experimental results also demonstrate that lip@PFH@O2 can effectively relieve biofilm hypoxia and enhance therapeutic efficacy of antibiotics. As a proof-of-concept, this research provides an innovative strategy for enhanced antibiotic therapy by relieving hypoxia, which may hold a bright future in combating biofilm-associated infections.},
}
@article {pmid32596100,
year = {2020},
author = {Hakimi Alni, R and Ghorban, K and Dadmanesh, M},
title = {Combined effects of Allium sativum and Cuminum cyminum essential oils on planktonic and biofilm forms of Salmonella typhimurium isolates.},
journal = {3 Biotech},
volume = {10},
number = {7},
pages = {315},
pmid = {32596100},
issn = {2190-572X},
abstract = {Salmonella typhimurium (S. typhimurium) represents an important global public health problem and has the ability to survive under desiccation conditions in foods and food processing facilities for years. The aim of this study was to investigate the effects of Allium sativum (A. sativum) and Cuminum cyminum (C. cyminum) essential oils (EOs) against planktonic growth, biofilm formation and quorum sensing (QS) of S. Typhimurium isolates, the strong biofilm producers. The major components of EOs were determined by gas chromatography-mass spectrometry (GC-MS). Biofilm formation of S. Typhimurium isolates was measured by crystal violet staining. Then, the effects of the EOs on the planktonic cell growth (using determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)), measurement of the synergistic effects of EOs (using checkerboard method), biofilm formation (using microtiter-plate test and scanning electron microscope (SEM)), and expression of QS and cellulose synthesis genes (using quantitative real-time PCR) were assessed. Finally, tetrazolium-based colorimetric (MTT) assay was used to examine EOs cytotoxicity on the Vero cell line. GC-MS analysis showed that terpineol, carene and pinene in C. cyminum EO and sulfur compounds in A. sativum EO were the major components of the plant extract. The Geometric mean of MIC values of the A. sativum and C. cyminum were 0.66 and 2.62 μL mL-1, respectively. The geometric means of the fractional inhibitory concentration index (FICi) for both EOs were calculated as 1.05. The qPCR results showed that MIC/2 concentrations of both EOs significantly down-regulated of QS (sdiA and luxS) and cellulose synthesis (csgD and adrA) genes. Scanning electron microscopy showed the EOs reduced the amount of S. Typhimurium mature biofilm. In general, we showed that C. cyminum and A. sativum EOs can be considered as the potential agents against planktonic and biofilm form of S. Typhimurium without any concern of cytotoxic effect at 4 MIC concentrations on the eukaryotic Vero cells.},
}
@article {pmid32595625,
year = {2020},
author = {Cui, P and Feng, L and Zhang, L and He, J and An, T and Fu, X and Li, C and Zhao, X and Zhai, Y and Li, H and Yan, W and Li, H and Luo, X and Lei, C and Wang, H and Yang, X},
title = {Antimicrobial Resistance, Virulence Genes, and Biofilm Formation Capacity Among Enterococcus species From Yaks in Aba Tibetan Autonomous Prefecture, China.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {1250},
pmid = {32595625},
issn = {1664-302X},
abstract = {Yaks provide necessities such as meat and milk for Tibetans living at high altitudes on and around the Qinghai-Tibetan Plateau. Enterococci are ubiquitous members of the animal gut microbiota that can cause biofilm-associated opportunistic infections. Meanwhile, multidrug-resistant Enterococcus also poses a serious threat to public health. This study aims to characterize antibiotic resistance, virulence genes, and biofilm formation of enterococci from yaks. From April 2018 to July 2019, we collected 395 fecal samples of yaks in Aba Tibetan Autonomous Prefecture, China. Enterococci isolated from the samples were identified and classified according to the 16S rDNA sequence. The antibiotic resistance of each isolate was detected according to the Kirby-Bauer disk diffusion method, and antibiotic resistance genes were detected by polymerase chain reaction (PCR) and sequencing. Enterococcal biofilms were assessed using standard procedures. Different virulence genes were detected by PCR and sequencing. In total, 381 enterococci strains were recovered, with Enterococcus faecalis (41.99%) and Enterococcus faecium (37.80%) being the predominant species. Many isolates were multidrug- resistant (60.37%) and showed a high resistance rate to rifampicin (64.30%) and tetracycline (61.54%). We also detected various antimicrobial resistance (AMR) genes in the tested strains. The E. faecalis strains had higher frequency of biofilm formation and virulence genes than other enterococcal species. This is the first report that shows yaks are repositories for drug-resistant enterococci with virulent determinants and biofilms that may spread into humans and to environment. This study also provides useful data suggesting that enterococci may pose a potential health risk to yaks. Therefore, active surveillance of AMR and pathogenesis in enterococci from yaks is urgently warranted.},
}
@article {pmid32595199,
year = {2020},
author = {Cherdvorapong, V and Panti, N and Suyotha, W and Tsuchiya, Y and Toyotake, Y and Yano, S and Wakayama, M},
title = {Prevention of oral biofilm formation and degradation of biofilm by recombinant α-1,3-glucanases from Streptomyces thermodiastaticus HF3-3.},
journal = {The Journal of general and applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.2323/jgam.2019.11.003},
pmid = {32595199},
issn = {1349-8037},
abstract = {The genes encoding α-1,3-glucanases (Agls; AglST1 and AglST2) from Streptomyces thermodiastaticus HF3-3 were cloned and were then expressed in Escherichia coli Rosetta-gami B (DE3). We purified the resultant histidine (His)-tagged α-1,3-glucanases (recombinant enzymes, rAglST1 and rAglST2). Both the recombinant enzymes were similar to the wild-type enzymes. We examined the effects of rAglST1 and rAglST2 on the formation and degradation of biofilms on glass plates with Streptococcus mutans NRBC 13955 by evaluating the biofilm content (%), release of reducing sugar (mM), release of S. mutans (log CFU/mL), and the biofilm structure using laser scanning microscopy (LSM). The results showed that after incubation for 16 h, rAglST1 and rAglST2 reduced the formation of biofilm to 52% and 49% of the control, respectively. The result may reflect the fact that the concentration of the reducing sugar and the number of S. mutans cells in the rAglATs-added medium were higher than in the control medium. After an 8-h treatment with rAglST1 and rAglST2, biofilms decreased to less than 60% of the control. The number of S. mutans cells in the reaction mixture gradually increased during the incubation period. The enzymes can degrade the biofilms that were pre-formed on the glass plate by more than 50% after a 30-min incubation in the presence of toothpaste ingredients (1% w/v of sodium fluoride, benzethonium chloride, and sodium dodecyl sulfate) at 50°C. Our study showed that rAglST1 and rAglST2 have advantageous properties for dental care applications.},
}
@article {pmid32594845,
year = {2020},
author = {Huang, C and Liu, LZ and Kong, HK and Law, COK and Hoa, PQ and Ho, PL and Lau, TCK},
title = {A novel incompatibility group X3 plasmid carrying blaNDM-1 encodes a small RNA that regulates host fucose metabolism and biofilm formation.},
journal = {RNA biology},
volume = {},
number = {},
pages = {1-10},
doi = {10.1080/15476286.2020.1780040},
pmid = {32594845},
issn = {1555-8584},
abstract = {The emergence of New Delhi metallo-beta-lactamase (NDM-1) has become a major health threat to clinical managements of gram-negative bacteria infections. A novel incompatibility group X3 plasmid (IncX3) pNDM-HN380 carrying blaNDM-1 has recently been found to epidemiologically link with multiple geographical areas in China. In this paper, we studied the metabolic responses of host bacteria E. coli J53 upon introduction of pNDM-HN380. A reduction of bacterial motility was observed in J53/pNDM-HN380. We profiled the RNA repertoires of the transconjugants and found a downregulation of genes involved in flagella and chemotaxis metabolic pathways at logarithmic (log) phase. We also identified a novel intragenic region (IGR) small RNA plas2. The plasmid-transcribed sRNA IGR plas2 was further characterized as a regulator of fucRwhich controls the fucose metabolism. By knockdown of IGR plas2 using an antisense decoy, we managed to inhibit the formation of bacterial biofilm of the host. Our study demonstrated a potential way of utilizing plasmid-transcribed sRNA against infectious bacteria.},
}
@article {pmid32594432,
year = {2020},
author = {Zeng, M and Yang, J and Wu, Z and Wang, W and Xu, L and Wu, N and Wang, C},
title = {Achieving single-stage autotrophic nitrogen removal by composite membrane aerated biofilm with gel under two microbial entrapping patterns: experimental and modeling aspects.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-020-09660-w},
pmid = {32594432},
issn = {1614-7499},
support = {21607114//National Natural Science Foundation of China/ ; 201901260//Tianjin Agricultrual Commission Program/ ; 2019YJSS035//Postgraduate research and innovation project of Tianjin/ ; },
abstract = {Single-stage autotrophic nitrogen removal offers advantages of low energy and carbon consumptions. Based on previous work about a novel composite membrane aerated biofilm (CMAB), two microbial entrapping patterns (mixed and stratified patterns) were evaluated for their applicability to artificially regulate the spatial distribution of distinct microbial aggregates for single-stage autotrophic nitrogen removal. Experimental results showed that the stratified pattern caused little accumulation of NO2- and NO3-, which leads to a superior nitrogen removal performance compared with the mixed pattern. Candidatus Kuenenia was found to be the major anammox bacterium in the gel film of the mixed pattern and the outer film of the stratified pattern. In contrast, Nitrosomonas, as a representative genus of ammonia-oxidizing bacteria, was substantially enriched in the inner film of the stratified pattern and the gel film of the mixed pattern. Finally, modeling results further confirmed the advantages of the stratified pattern with respect to the formation of rational microbial and nutrient profiles in gel films. The ratio of partial nitrification and anammox film thicknesses should remain below 3:2 to obtain a high fraction of anammox bacteria and to avoid NO2- accumulation. Increasing O2 surface loading does not affect microbial profiles, but can greatly promote the TN removal performance only in the stratified pattern. Overall, the stratified pattern should be employed to achieve optimal microbial profiles and nitrogen removal efficiency.},
}
@article {pmid32593786,
year = {2020},
author = {Gao, L and Han, F and Zhang, X and Liu, B and Fan, D and Sun, X and Zhang, Y and Yan, L and Wei, D},
title = {Simultaneous nitrate and dissolved organic matter removal from wastewater treatment plant effluent in a solid-phase denitrification biofilm reactor.},
journal = {Bioresource technology},
volume = {314},
number = {},
pages = {123714},
doi = {10.1016/j.biortech.2020.123714},
pmid = {32593786},
issn = {1873-2976},
abstract = {In the present study, an up-flow solid-phase denitrification biofilm reactor (US-DBR) was established for simultaneous nitrate and dissolved organic matter (DOM) removal from wastewater treatment plant effluent. After 100 days operation, the nitrate and COD removal efficiencies were high of 97% and 80%, respectively. According to EEM-FRI analysis, aromatic and tryptophan protein-like, humic-like and fulvic acid-like substances were identified in DOM. Additionally, protein-like substances in DOM components were much easier transformed as carbon source for denitrification. Moreover, protein secondary structure of DOM changed significantly due to the biodegradation and microorganisms metabolic process. High-throughput sequencing analysis implied that Simplicispira, Diaphorobacter, Hydrogenophaga, Pseudoxanthmonas and Stenotrophomonas were the dominate genera in the whole of US-DBR, that were responsible for the removal of nitrate, organics and degradation of solid carbon source, respectively. This study provided a further biological basis about practical application of solid-phase denitrification for simultaneously remove nitrate and organic matter.},
}
@article {pmid32593705,
year = {2020},
author = {Sorkhdini, P and Gregory, RL and Crystal, YO and Tang, Q and Lippert, F},
title = {Effectiveness of In Vitro Primary Coronal Caries Prevention with Silver Diamine Fluoride - chemical vs biofilm models.},
journal = {Journal of dentistry},
volume = {},
number = {},
pages = {103418},
doi = {10.1016/j.jdent.2020.103418},
pmid = {32593705},
issn = {1879-176X},
abstract = {OBJECTIVES: The main goal of this study was to investigate the effectiveness of SDF and its individual components, silver (Ag+) and fluoride (F-) ions, in preventing enamel demineralization using biofilm and chemical models.<br><br>METHODES: Polished human enamel specimens were assigned to five treatment groups (n = 18 per group): SDF (38%); SDF followed by application of a saturated solution of potassium iodide (SDF + KI); silver nitrate (AgNO3; silver control, 253,900 ppm Ag+); potassium fluoride (KF; fluoride control, 44,800 ppm F); deionized water (DIW). Treatments were applied once to sound enamel. In the biofilm model, specimens were demineralized by aerobic overnight incubation using cariogenic bacteria isolated from human saliva in brain heart infusion supplemented with 0.2% sucrose for three days. In the chemical model, enamel specimens were immersed in a demineralizing solution containing 0.1 M lactic acid, 4.1 mM CaCl2, 8.0 mM KH2PO4, 0.2% Carbopol 907, pH adjusted to 5.0 for five days. Vickers surface microhardness was used to determine the extent of enamel demineralization. Data were analyzed using one-way ANOVA.<br><br>RESULTS: In the chemical model, there was no statistically significant difference between SDF and SDF + KI in preventing coronal caries (p < 0.0001). In the biofilm model, SDF + KI was significantly less effective in preventing demineralization than SDF (p < 0.0001). In both models, SDF and SDF + KI were superior in their ability to prevent caries lesion formation than AgNO3 and DIW.<br><br>CONCLUSION: KI application after SDF treatment appears to impair SDF's ability to prevent biofilm-mediated but not chemically induced demineralization.<br><br>CLINICAL SIGNIFICANCE: SDF may be a viable option in preventing primary coronal caries.},
}
@article {pmid32593105,
year = {2020},
author = {Xiang, Y and Shao, Z and Chai, H and Ji, F and He, Q},
title = {Functional microorganisms and enzymes related nitrogen cycle in the biofilm performing simultaneous nitrification and denitrification.},
journal = {Bioresource technology},
volume = {314},
number = {},
pages = {123697},
doi = {10.1016/j.biortech.2020.123697},
pmid = {32593105},
issn = {1873-2976},
abstract = {Simultaneous nitrification and denitrification (SND) is a potential energy-saving process in wastewater treatment while the nitrogen removal mechanism is still unclear due to the lack of information about the functional microbes and enzymes. Sequencing batch biofilm reactors were implemented to achieve efficient SND. Eight nitrogen removal related microorganisms out of the top abundant 20 microbial community and reference species were used to construct a phylogenetic tree. Functional enzymes and modules analysis were investigated to reveal the SND pathway: in the aerobic part of the biofilm, ammonia oxidation was catalyzed by complete ammonia oxidizers while in the inner anoxic part, denitrification, dissimilatory nitrate reduction (DNRA) and nitrogen fixation (NF) cooperated to stimulate nitrate removal. These results provide a practical aeration control strategy to achieve SND and indicate that DNRA and NF are important nitrogen removal pathways that should not be ignored in the SND mechanism.},
}
@article {pmid32592930,
year = {2020},
author = {Kato, K and Tamura, K and Shimazaki, Y},
title = {Oral biofilm uptake of mineral ions released from experimental toothpaste containing surface pre-reacted glass-ionomer (S-PRG) filler.},
journal = {Archives of oral biology},
volume = {117},
number = {},
pages = {104777},
doi = {10.1016/j.archoralbio.2020.104777},
pmid = {32592930},
issn = {1879-1506},
abstract = {OBJECTIVE: To clarify the fluoride/mineral kinetics in an oral biofilm following concurrent application of fluoride and other mineral ions released from experimental toothpaste containing S-PRG filler using depth-specific analysis.<br><br>STUDY DESIGN: Twenty subjects wore in situ plaque-generating devices, comprised of a pair of enamel slabs, and a biofilm was allowed to form. The devices were removed after three days, immersed in the toothpaste filtrate containing Al, B, Sr and F ions for 1 min, and then reinserted at the same location. After 30 min, the devices were removed and samples were obtained by sectioning into outer, middle and inner biofilm layers (300-μm thick). Samples treated with filtrate containing F without S-PRG filler extract served as the control. Fluoride and the three other mineral ions extracted from 4-μm sections were quantified using a fluoride electrode and ICP-AES, respectively. The results were corrected for biomass volume, estimated by the area measurement of stained 2-μm sections.<br><br>RESULTS: The mean uptake ratios (S-PRG/control, ng/mm3) of Al, B, Sr and F were 186.6/53.7, 58.4/25.0, 456.9/125.7 and 43.6/12.0, respectively, in the outer layer, indicating that the mineral ions could easily diffuse into the biofilm. F concentrations in the outer biofilm treated using filtrate with S-PRG filler extract were significantly higher than those in controls, although both biofilms were exposed to filtrates containing the same level of F.<br><br>CONCLUSIONS: The results suggest that toothpaste containing S-PRG filler promotes fluoride retention in oral biofilms via the uptake of other mineral ions.},
}
@article {pmid32592827,
year = {2020},
author = {Braga, AS and de Melo Simas, LL and Pires, JG and Souza, BM and de Souza Rosa de Melo, FP and Saldanha, LL and Dokkedal, AL and Magalhães, AC},
title = {Antibiofilm and anti-caries effects of an experimental mouth rinse containing Matricaria chamomilla L. extract under microcosm biofilm on enamel.},
journal = {Journal of dentistry},
volume = {},
number = {},
pages = {103415},
doi = {10.1016/j.jdent.2020.103415},
pmid = {32592827},
issn = {1879-176X},
abstract = {OBJECTIVE: This study evaluated the antibiofilm and anti-caries effects of an experimental mouth rinse containing aqueous extract of Matricaria chamomilla L.<br><br>METHODS: Microcosm biofilm was produced on bovine enamel, from pooled human saliva mixed with McBain saliva, under 0.2 % sucrose exposure, for 5 days. The biofilm was daily treated using (1 mL/1 min): Vochysia tucanorum Mart. (2.5 mg/mL); Myrcia bella Cambess. (1.25 mg/mL); Matricaria chamomilla L. (20 mg/mL); Malva sylvestris (Malvatricin® Plus-Daudt); 0.12 % Chlorhexidine (PerioGard®-Palmolive, Positive control) and PBS (Negative control). The % dead bacteria, biofilm thickness, EPS biovolume, lactic acid concentration, the CFU counting (total microorganisms, Lactobacillus sp., total streptococci and Streptococcus mutans/S. sobrinus) were determined. Enamel demineralization was measured by TMR.<br><br>RESULTS: All mouth rinses induced bacterial death compared to PBS (p < 0.0001). The biofilm thickness varied from 12 ± 2 µm (chlorhexidine) to 18 ± 2 µm (V. tucanorum) (ANOVA/Tukey, p < 0.0001). The EPS biovolume varied from 7(4)% (chlorhexidine) to 30(20)% (PBS) (Kruskal-Wallis/Dunn, p < 0.0001). The lactic acid production was reduced by M. sylvestris (1.1 ± 0.2 g/L) and chlorhexidine (0.6 ± 0.2 g/L) compared to PBS (2.6 ± 1.3 g/L) (ANOVA, p < 0.0001). Malva sylvestris and chlorhexidine showed significant low CFU for total microorganisms, Lactobacillus sp. and total streptococci. Only chlorhexidine significantly reduced S. mutans/S. sobrinus. CFUs for total streptococci and Lactobacillus sp, were also significantly reduced by M. chamomilla L. Malva sylvestris (63.4 % of mineral loss reduction), chlorhexidine (47.4 %) and M. chamomilla L. (39.4 %) significantly reduced enamel demineralization compared to PBS (ANOVA/Tukey, p < 0.0001).<br><br>CONCLUSION: M. chamomilla L. has lower antibiofilm action, but comparable anti-caries effect to those found for chlorhexidine, under this model.<br><br>CLINICAL RELEVANCE: This study shows that the antibiofilm and anti-caries potential may vary between the commercial and experimental mouth rinses containing natural agents, with promising results for those containing Matricaria chamomilla L. and Malva Sylvestris.},
}
@article {pmid32590200,
year = {2020},
author = {Koşarsoy Ağçeli, G and Cihangir, N},
title = {Nano-sized biopolymer levan: Its antimicrobial, anti-biofilm and anti-cancer effects.},
journal = {Carbohydrate research},
volume = {494},
number = {},
pages = {108068},
doi = {10.1016/j.carres.2020.108068},
pmid = {32590200},
issn = {1873-426X},
abstract = {Among other polysaccharides, levan is a fructan with great potential in biotechnological applications due to its functional properties. The levan has only been available in small quantities because of its high cost. Here, a levan-producing microorganism was isolated from soil and identified as Pseudomonas mandelii. TGA, SEM, FTIR, 1H NMR, 13C NMR and Zetasizer analyses were used to characterize thermal properties and the morphology of the levan. It is the first time, the levan synthesized from P. mandelii is reported as nano sized. The culture conditions were optimized. It is the most comprehensive optimization study regarding levan production of P. mandelii up to the present. The optimum conditions found for levan production were 37 °C, at pH 8, under static conditions, with 15% sucrose and 1.5% mannitol as the C sources and yeast extract as the N source. In addition, the levan production yield was calculated at optimum conditions. Antibacterial activity of levan was evaluated against bacteria and the largest zone of inhibition was observed against E. coli at a concentration of 1000 μg/mL. Antibiofilm activity of levan was evaluated, and we found that all levan concentrations inhibited biofilm formation of all microorganisms in the study. We have shown that the levan from Pseudomonas mandelii induce cytotoxicity breast (MCF-7) cells in a dose-dependent manner.},
}
@article {pmid32589289,
year = {2020},
author = {Wang, S and Breslawec, AP and Li, C and Poulin, MB},
title = {A Colorimetric Assay to Enable High-Throughput Identification of Biofilm Exopolysaccharide-Hydrolyzing Enzymes.},
journal = {Chemistry (Weinheim an der Bergstrasse, Germany)},
volume = {},
number = {},
pages = {},
doi = {10.1002/chem.202002475},
pmid = {32589289},
issn = {1521-3765},
abstract = {Glycosidase enzymes that hydrolyze the biofilm exopolysaccharide poly-ß-(1,6)-N-acetylglucosamine (PNAG) are critical tools to study biofilm and potential therapeutic biofilm dispersal agents. Function-driven metagenomic screening is a powerful approach for discovery of new glycosidase but requires sensitive assays capable of distinguishing between the desired enzyme and functionally related enzymes. Here, we report the synthesis of a colorimetric PNAG disaccharide analog whose hydrolysis by PNAG glycosidases results in production of para-nitroaniline that can be continuously monitored at 410 nm. The assay is specific for enzymes capable of hydrolyzing PNAG and not related ß-hexosaminidase enzymes with alternative glycosidic linkage specificities. This analog enabled development of a continuous colorimetric assay for detection of PNAG hydrolyzing enzyme activity in crude E. coli cell lysates and suggest that this disaccharide probe will be critical for establishing the functional screening of metagenomic DNA libraries.},
}
@article {pmid32588628,
year = {2020},
author = {Kang, J and Liu, L and Liu, Y and Wang, X},
title = {Ferulic Acid Inactivates Shigella flexneri through Cell Membrane Destructieon, Biofilm Retardation, and Altered Gene Expression.},
journal = {Journal of agricultural and food chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.jafc.0c01901},
pmid = {32588628},
issn = {1520-5118},
abstract = {Antibiotic resistance and capacity for biofilm formation of Shigella flexneri render previous prevention and control strategies minimally effective. Ferulic acid (FA) has been demonstrated to be useful due to its application in foods as an alternative natural preservative. However, information regarding the S. flexneri phenotype and molecular responses to FA exposure is limited. The present study investigated the effects of FA on S. flexneri planktonic growth and biofilm formation. The results demonstrated that the cell membrane of S. flexneri in planktonic growth mode exhibited irreversible destruction after FA exposure, as characterized by decreased cell viability, leakage of cytoplasmic constituents, accelerated adenosine triphosphate (ATP) consumption, cell membrane depolarization, and cellular morphological changes. FA significantly inhibited S. flexneri adhesion and biofilm formation at a working concentration (1/8 MIC) that almost did not inhibit planktonic growth. Transcriptomics profiling showed that the exposure to a subinhibitory concentration of FA dramatically altered gene expression in the S. flexneri biofilm, as a total of 169 differentially expressed genes (DEGs) were upregulated and 533 DEGs were downregulated, compared to the intact biofilm. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that the DEGs were mainly involved in pathways of ribosomes, ABC transporters, and the citrate cycle. Furthermore, we show that FA altered the transcription of S. flexneri genes associated with adhesion, transcriptional regulation, and the synthesis and transport of extracellular polymeric substances that contribute to biofilm formation. These data provide novel insights into S. flexneri behavioral responses to FA exposure and suggest that FA could effectively constrain S. flexneri and its biofilm formation.},
}
@article {pmid32588553,
year = {2020},
author = {Parlak, O and Richter-Dahlfors, A},
title = {Bacterial Sensing and Biofilm Monitoring for Infection Diagnostics.},
journal = {Macromolecular bioscience},
volume = {},
number = {},
pages = {e2000129},
doi = {10.1002/mabi.202000129},
pmid = {32588553},
issn = {1616-5195},
support = {//Familjen Erling-Perssons Stiftelse/ ; VF-2019-0110//Kungliga Tekniska Högskolan/ ; 1-249/2019//Karolinska Institutet/ ; KAW2014.0387//Knut och Alice Wallenbergs Stiftelse/ ; },
abstract = {Recent insights into the rapidly emerging field of bacterial sensing and biofilm monitoring for infection diagnostics are discussed as well as recent key developments and emerging technologies in the field. Electrochemical sensing of bacteria and bacterial biofilm via synthetic, natural, and engineered recognition, as well as direct redox-sensing approaches via algorithm-based optical sensing, and tailor-made optotracing technology are discussed. These technologies are highlighted to answer the very critical question: &quot;how can fast and accurate bacterial sensing and biofilm monitoring be achieved? Following on from that: &quot;how can these different sensing concepts be translated for use in infection diagnostics? A central obstacle to this transformation is the absence of direct and fast analysis methods that provide high-throughput results and bio-interfaces that can control and regulate the means of communication between biological and electronic systems. Here, the overall progress made to date in building such translational efforts at the level of an individual bacterial cell to a bacterial community is discussed.},
}
@article {pmid32587287,
year = {2020},
author = {do Nascimento Dias, J and de Souza Silva, C and de Araújo, AR and Souza, JMT and de Holanda Veloso Júnior, PH and Cabral, WF and da Glória da Silva, M and Eaton, P and de Souza de Almeida Leite, JR and Nicola, AM and Albuquerque, P and Silva-Pereira, I},
title = {Mechanisms of action of antimicrobial peptides ToAP2 and NDBP-5.7 against Candida albicans planktonic and biofilm cells.},
journal = {Scientific reports},
volume = {10},
number = {1},
pages = {10327},
pmid = {32587287},
issn = {2045-2322},
abstract = {Candida albicans is a major cause of human infections, ranging from relatively simple to treat skin and mucosal diseases to systemic life-threatening invasive candidiasis. Fungal infections treatment faces three major challenges: the limited number of therapeutic options, the toxicity of the available drugs, and the rise of antifungal resistance. In this study, we demonstrate the antifungal activity and mechanism of action of peptides ToAP2 and NDBP-5.7 against planktonic cells and biofilms of C. albicans. Both peptides were active against C. albicans cells; however, ToAP2 was more active and produced more pronounced effects on fungal cells. Both peptides affected C. albicans membrane permeability and produced changes in fungal cell morphology, such as deformations in the cell wall and disruption of ultracellular organization. Both peptides showed synergism with amphotericin B, while ToAP2 also presents a synergic effect with fluconazole. Besides, ToAP2 (6.25 µM.) was able to inhibit filamentation after 24 h of treatment and was active against both the early phase and mature biofilms of C. albicans. Finally, ToAP2 was protective in a Galleria mellonella model of infection. Altogether these results point to the therapeutic potential of ToAP2 and other antimicrobial peptides in the development of new therapies for C. albicans infections.},
}
@article {pmid32586125,
year = {2020},
author = {Kannappan, A and Durgadevi, R and Srinivasan, R and Lagoa, RJL and Packiavathy, IASV and Pandian, SK and Veera Ravi, A},
title = {2-Hydroxy-4-methoxybenzaldehyde from Hemidesmus indicus is antagonistic to Staphylococcus epidermidis biofilm formation.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-15},
doi = {10.1080/08927014.2020.1777989},
pmid = {32586125},
issn = {1029-2454},
abstract = {Staphylococcus epidermidis (SE) is an opportunistic nosocomial pathogen that accounts for recalcitrant device-related infections worldwide. Owing to the growing interest in plants and their secondary metabolites targeting bacterial adhesion, this study was intended to uncover the anti-biofilm potential of Hemidesmus indicus and its major constituent 2-hydroxy-4-methoxybenzaldehyde (HMB) against SE. The minimum biofilm inhibitory concentration (MBIC) of H. indicus root extract and HMB were found to be 500 and 250 µg ml-1, respectively. The results of time-dependent biofilm inhibition and mature biofilm disruption assays confirmed that HMB targets initial cell adhesion. Furthermore, interference by HMB in the expression of adhesin genes (icaA, aap and bhp) and biofilm components was associated with an increased susceptibility of SE to oxidative stress and antibiotics. To conclude, this study reports for the first time HMB as a potential drug against SE biofilms.},
}
@article {pmid32585940,
year = {2020},
author = {Szymczyk-Ziółkowska, P and Hoppe, V and Rusińska, M and Gąsiorek, J and Ziółkowski, G and Dydak, K and Czajkowska, J and Junka, A},
title = {The Impact of EBM-Manufactured Ti6Al4V ELI Alloy Surface Modifications on Cytotoxicity toward Eukaryotic Cells and Microbial Biofilm Formation.},
journal = {Materials (Basel, Switzerland)},
volume = {13},
number = {12},
pages = {},
doi = {10.3390/ma13122822},
pmid = {32585940},
issn = {1996-1944},
support = {049M/0001/19//Politechnika Wrocławska/ ; SUB.D230.20.002//Uniwersytet Medyczny im. Piastów Slaskich we Wroclawiu/ ; },
abstract = {Electron beam melting (EBM) is an additive manufacturing technique, which allows forming customized implants that perfectly fit the loss of the anatomical structure of bone. Implantation efficiency depends not only on the implant's functional or mechanical properties but also on its surface properties, which are of great importance with regard to such biological processes as bone regeneration or microbial contamination. This work presents the impact of surface modifications (mechanical polishing, sandblasting, and acid-polishing) of EBM-produced Ti6Al4V ELI implants on essential biological parameters. These include wettability, cytotoxicity toward fibroblast and osteoblast cell line, and ability to form biofilm by Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. Obtained results indicated that all prepared surfaces exhibited hydrophilic character and the highest changes of wettability were obtained by chemical modification. All implants displayed no cytotoxicity against osteoblast and fibroblast cell lines regardless of the modification type. In turn, the quantitative microbiological tests and visualization of microbial biofilm by means of electron microscopy showed that type of implant's modification correlated with the species-specific ability of microbes to form biofilm on it. Thus, the results of the presented study confirm the relationship between such technological aspects as surface modification and biological properties. The provided data are useful with regard to applications of the EBM technology and present a significant step towards personalized, customized implantology practice.},
}
@article {pmid32585445,
year = {2020},
author = {Dornelas Figueira, LM and Ricomini Filho, AP and da Silva, WJ and Del BeL Cury, AA and Ruiz, KGS},
title = {Glucose effect on Candida albicans biofilm during tissue invasion.},
journal = {Archives of oral biology},
volume = {117},
number = {},
pages = {104728},
doi = {10.1016/j.archoralbio.2020.104728},
pmid = {32585445},
issn = {1879-1506},
abstract = {OBJECTIVE: To evaluate, in vitro, the effect of two glucose concentrations (0.1 mM and 1.0 mM, simulating glucose concentration in saliva of healthy and diabetic individuals) on Candida albicans biofilm grown on epithelial monolayer.<br><br>MATERIAL AND METHODS: C. albicans was inoculated on epithelial monolayers supplemented with 0.1 mM, 1.0 mM or no glucose. Control groups without C. albicans were also evaluated. Tissue response was assessed through the production of Interleukin-1α, Interleukin-8, Interleukin-6, Interleukin-10 and tumor necrosis factor-α. The complex of monolayer and biofilms were evaluated by quantitative reverse transcription polymerase chain reaction for expression of E-cadherin (CDH1), Caspase-3 (CASP3), β-defensin-1 (DEFB-1) and β-defensin-3 (DEFB-3). The biofilm architecture was visualized by confocal laser scanning microscopy.<br><br>RESULTS: The production of Interleukin-1α and Interleukin-8 were increased in the presence of C. albicans (p < 0.05). Glucose did not interfere in the release of any cytokine evaluated. C. albicans downregulated transcripts for CDH1 (p < 0.05). Glucose did not induce a significant change in CDH1, CASP3, DEFB-1 and DEFB-3 messenger RNA expression. The biofilms were more structured in the presence of glucose, but no difference in the diffusion of hyphae through the epithelial cells were observed.<br><br>CONCLUSIONS: The data suggest that glucose concentration does not affect the behavior of C. albicans during tissue invasion and other mechanisms must be related to the greater susceptibility of diabetic individuals to candidiasis.},
}
@article {pmid32585104,
year = {2020},
author = {Li, Y and Liu, X and Li, B and Zheng, Y and Han, Y and Chen, DF and Yeung, KWK and Cui, Z and Liang, Y and Li, Z and Zhu, S and Wang, X and Wu, S},
title = {Near-Infrared Light Triggered Phototherapy and Immunotherapy for Elimination of Methicillin-Resistant Staphylococcus aureus Biofilm Infection on Bone Implant.},
journal = {ACS nano},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsnano.0c01486},
pmid = {32585104},
issn = {1936-086X},
abstract = {Clinically, methicillin-resistant Staphylococcus aureus (MRSA) biofilm infection inevitably induces the failure of bone implants. Herein, a hydrophilic and viscous hydrogel of poly(vinyl alcohol) modified with chitosan, polydopamine, and NO release donor was formed on a red phosphorus nanofilm deposited on a titanium implant (Ti-RP/PCP/RSNO). Under the irradiation of near-infrared light (NIR), peroxynitrite (•ONOO-) was formed by the reaction between the released NO and superoxide (•O2-) produced by the RP nanofilm. Specifically, we revealed the antibacterial mechanism of the ONOO- against the MRSA biofilm. In addition, osteogenic differentiation was promoted and inflammatory polarization was regulated by the released NO without NIR irradiation through upregulating the expression of Opn and Ocn genes and TNF-α. The MRSA biofilm was synergistically eradicated by •ONOO-, hyperthermia, and •O2- under NIR irradiation as well as the immunoreaction of the M1 polarization. The in vivo results also confirmed the excellent osteogenesis and biofilm eradication by released NO from the RP/PCP/RSNO system under NIR irradiation, indicating the noninvasive tissue reconstruction of MRSA-infected tissues through phototherapy and immunotherapy.},
}
@article {pmid32584995,
year = {2020},
author = {Costa, ACBP and Back-Brito, GN and Mayer, FL and Hube, B and Wilson, D},
title = {Candida albicans Mrv8, is involved in epithelial damage and biofilm formation.},
journal = {FEMS yeast research},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsyr/foaa033},
pmid = {32584995},
issn = {1567-1364},
abstract = {Candida albicans is the most common human fungal pathogen that can cause superficial and deep-seated infections in susceptible individuals. Despite its medical importance, the vast majority of C. albicans genes remain of unknown function. Here we report a role for the lineage-specific gene, MRV8, in host pathogen interactions, mycelial microcolony maturation and biofilm formation. In silico analysis indicated that MRV8 encodes a four-pass transmembrane protein unique to the closely related pathogens C. albicans and Candida dubliniensis. Deletion of MRV8 did not affect C. albicans adherence to, or initial invasion into human oral epithelia, but inhibited mycelial development and strongly reduced epithelial damage. mrv8Δ/Δ cells exhibited a media-dependent defect in biofilm formation and mutant biofilm metabolic activity was enhanced by cyclosporin A. mrv8Δ/Δ biofilms were more tolerant to treatment with caspofungin, but not to fluconazole or amphotericin B. Co-stimulation with calcium chloride and calcofluor white rescued biofilm growth in the presence of caspofungin, and this rescue-effect was Mrv8-dependent. Together, our data demonstrate an important role for a lineage-specific gene (MRV8) in C. albicans biofilm formation, drug tolerance and host-pathogen interactions.},
}
@article {pmid32583509,
year = {2020},
author = {Desch, A and Freifrau von Maltzahn, N and Stumpp, N and Dalton, M and Yang, I and Stiesch, M},
title = {Biofilm formation on zirconia and titanium over time - an in vivo model study.},
journal = {Clinical oral implants research},
volume = {},
number = {},
pages = {},
doi = {10.1111/clr.13632},
pmid = {32583509},
issn = {1600-0501},
abstract = {OBJECTIVES: The aim of this study was to evaluate volume, vitality and diversity of biofilms on the abutment materials zirconia and titanium as a function of time using an in vivo model for the biofilm formation.<br><br>MATERIALS AND METHODS: The development of biofilms on zirconia and titanium grade 4 test specimens in the human oral cavity over time was analysed. After pretreatment, a total of 96 titanium and 96 zirconia discs were fixed on 12 composite splints, which were worn by 12 volunteers. After 6 hours, 24 hours, 3 days and 5 days, biofilms on 48 specimens of each material were analysed with confocal laser scanning microscopy (CLSM). The microbiota composition on the other 48 test specimens was examined using full-length 16S sequence analysis. Statistical analysis was performed by SPSS and R, level of significance was set at 0.05.<br><br>RESULTS: CLSM analysis of the biofilms revealed significant changes in volume over time on zirconia and titanium. The material did not significantly influence the volume or live/dead ratio at the individual time points. The composition of the microbiome was influenced by the age of the biofilm, but not by the material of the test specimen. The most frequently found bacteria were Streptococcus spp., followed by Neisseria spp., Rothia spp., Haemophilus spp., Gemella spp. and Abiotrophia spp..<br><br>CONCLUSIONS: On both materials, the quantity and diversity of the microbiome increased over time. Apart from a slight difference in Veillonella abundance at one time point, there were no significant differences between zirconia and titanium.},
}
@article {pmid32583190,
year = {2020},
author = {Kallscheuer, N and Wiegand, S and Boedeker, C and Peeters, SH and Jogler, M and Heuer, A and Jetten, MSM and Rohde, M and Jogler, C},
title = {Caulifigura coniformis gen. nov., sp. nov., a novel member of the family Planctomycetaceae isolated from a red biofilm sampled in a hydrothermal area.},
journal = {Antonie van Leeuwenhoek},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10482-020-01439-w},
pmid = {32583190},
issn = {1572-9699},
support = {KA 4967/1-1//DFG/ ; JO 893/4-1//DFG/ ; ALWOP.308//Nederlandse Organisatie voor Wetenschappelijk Onderzoek/ ; 024002002//Soehngen Institute for Anaerobic Microbiology/ ; },
abstract = {Pan44T, a novel strain belonging to the phylum Planctomycetes, was isolated from a red biofilm in a hydrothermal area close to the island Panarea in the Tyrrhenian Sea north of Sicily, Italy. The strain forms white colonies on solid medium and displays the following characteristics: cell division by budding, formation of rosettes, presence of matrix or fimbriae and long stalks. The cell surface has an interesting and characteristic texture made up of triangles and rectangles, which leads to a pine cone-like morphology of the strain. Strain Pan44T is mesophilic (temperature optimum 26 °C), slightly alkaliphilic (pH optimum 8.0), aerobic and heterotrophic. The strain has a genome size of 6.76 Mb with a G + C content of 63.2%. Phylogenetically, the strain is a member of the family Planctomycetaceae, order Planctomycetales, class Planctomycetia. Our analysis supports delineation of strain Pan44T from all known genera in this family, hence, we propose to assign it to a novel species within a novel genus, for which we propose the name Caulifigura coniformis gen. nov., sp. nov., represented by Pan44T (DSM 29405T = LMG 29788T) as the type strain.},
}
@article {pmid32582564,
year = {2020},
author = {Kim, JH and Ruegger, PR and Lebig, EG and VanSchalkwyk, S and Jeske, DR and Hsiao, A and Borneman, J and Martins-Green, M},
title = {High Levels of Oxidative Stress Create a Microenvironment That Significantly Decreases the Diversity of the Microbiota in Diabetic Chronic Wounds and Promotes Biofilm Formation.},
journal = {Frontiers in cellular and infection microbiology},
volume = {10},
number = {},
pages = {259},
pmid = {32582564},
issn = {2235-2988},
support = {R21 AI138188/AI/NIAID NIH HHS/United States ; R35 GM124724/GM/NIGMS NIH HHS/United States ; },
abstract = {Diabetics chronic wounds are characterized by high levels of oxidative stress (OS) and are often colonized by biofilm-forming bacteria that severely compromise healing and can result in amputation. However, little is known about the role of skin microbiota in wound healing and chronic wound development. We hypothesized that high OS levels lead to chronic wound development by promoting the colonization of biofilm-forming bacteria over commensal/beneficial bacteria. To test this hypothesis, we used our db/db-/- mouse model for chronic wounds where pathogenic biofilms develop naturally after induction of high OS immediately after wounding. We sequenced the bacterial rRNA internal transcribed spacer (ITS) gene of the wound microbiota from wound initiation to fully developed chronic wounds. Indicator species analysis, which considers a species' fidelity and specificity, was used to determine which bacterial species were strongly associated with healing wounds or chronic wounds. We found that healing wounds were colonized by a diverse and dynamic bacterial microbiome that never developed biofilms even though biofilm-forming bacteria were present. Several clinically relevant species that are present in human chronic wounds, such as Cutibacterium acnes, Achromobacter sp., Delftia sp., and Escherichia coli, were highly associated with healing wounds. These bacteria may serve as bioindicators of healing and may actively participate in the processes of wound healing and preventing pathogenic bacteria from colonizing the wound. In contrast, chronic wounds, which had high levels of OS, had low bacterial diversity and were colonized by several clinically relevant, biofilm-forming bacteria such as Pseudomonas aeruginosa, Enterobacter cloacae, Corynebacterium frankenforstense, and Acinetobacter sp. We observed unique population trends: for example, P. aeruginosa associated with aggressive biofilm development, whereas Staphylococcus xylosus was only present early after injury. These findings show that high levels of OS in the wound significantly altered the bacterial wound microbiome, decreasing diversity and promoting the colonization of bacteria from the skin microbiota to form biofilm. In conclusion, bacteria associated with non-chronic or chronic wounds could function as bioindicators of healing or non-healing (chronicity), respectively. Moreover, a better understanding of bacterial interactions between pathogenic and beneficial bacteria within an evolving chronic wound microbiota may lead to better solutions for chronic wound management.},
}
@article {pmid32582122,
year = {2020},
author = {Yan, J and Xie, J},
title = {Comparative Proteome Analysis of Shewanella putrefaciens WS13 Mature Biofilm Under Cold Stress.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {1225},
pmid = {32582122},
issn = {1664-302X},
abstract = {Worldwide, Shewanella putrefaciens is the predominant seafood spoilage microorganism during cold storage. This bacterium can attach to biotic/abiotic surfaces to form biofilms which contribute to seafood quality degradation and shelf-life reduction. The mechanism of S. putrefaciens biofilm formation is not yet described. Crystal violet staining in combination with confocal laser scanning microscopy (CLSM) was used to study the sequence of events leading to the establishment of a mature biofilm at 4, 15, and 30°C. In addition, the main chemical constituents of the mature biofilm were determined by Raman spectroscopy (RM), whereas, comparative proteomic analysis was used to quantify changes in metabolic pathways and to find out underlying protein determinants. The physical dimensions of the mature biofilm, i.e., biomass, biovolume, and mean thickness, were higher at 4°C when compared to 15 and 30°C. The variations of proteins measured by RM confirmed the importance of proteins during the formation of a mature biofilm. Comparative proteomic analysis showed that siderophore and iron chelate transport proteins were down-regulated during mature biofilm formation. The down-regulated aforementioned proteins are involved in promoting iron storage in response to a higher demand for metabolic energy, whereas, the upregulated proteins of the sulfur relay system, pyrimidine metabolism, and purine metabolism are related to bacterial adaptability. Synthesis of proteins related to cold stress was increased and proteins involved in aminoacyl-tRNA biosynthesis were up-regulated, whereas, proteins involved in aminopeptidase activity were down-regulated. Proteolysis to scavenge energy was reduced as proteins involved in pyrophosphatase activity were up-regulated. Also extracellular eDNA was found which may play an important role in maintaining the stability of mature S. putrefaciens biofilm structures under cold stress. This work provides a better understanding of the role of proteins in mature biofilms. In addition, the biofilm formation mechanism of a psychrotrophic spoilage bacterial species at low temperature is explored, which may contribute to generating biofilm controlling strategies during seafood preservation and processing.},
}
@article {pmid32582085,
year = {2020},
author = {Trego, AC and Galvin, E and Sweeney, C and Dunning, S and Murphy, C and Mills, S and Nzeteu, C and Quince, C and Connelly, S and Ijaz, UZ and Collins, G},
title = {Growth and Break-Up of Methanogenic Granules Suggests Mechanisms for Biofilm and Community Development.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {1126},
pmid = {32582085},
issn = {1664-302X},
abstract = {Methanogenic sludge granules are densely packed, small, spherical biofilms found in anaerobic digesters used to treat industrial wastewaters, where they underpin efficient organic waste conversion and biogas production. Each granule theoretically houses representative microorganisms from all of the trophic groups implicated in the successive and interdependent reactions of the anaerobic digestion (AD) process. Information on exactly how methanogenic granules develop, and their eventual fate will be important for precision management of environmental biotechnologies. Granules from a full-scale bioreactor were size-separated into small (0.6-1 mm), medium (1-1.4 mm), and large (1.4-1.8 mm) size fractions. Twelve laboratory-scale bioreactors were operated using either small, medium, or large granules, or unfractionated sludge. After >50 days of operation, the granule size distribution in each of the small, medium, and large bioreactor sets had diversified beyond-to both bigger and smaller than-the size fraction used for inoculation. Interestingly, extra-small (XS; <0.6 mm) granules were observed, and retained in all of the bioreactors, suggesting the continuous nature of granulation, and/or the breakage of larger granules into XS bits. Moreover, evidence suggested that even granules with small diameters could break. &quot;New&quot; granules from each emerging size were analyzed by studying community structure based on high-throughput 16S rRNA gene sequencing. Methanobacterium, Aminobacterium, Propionibacteriaceae, and Desulfovibrio represented the majority of the community in new granules. H2-using, and not acetoclastic, methanogens appeared more important, and were associated with abundant syntrophic bacteria. Multivariate integration (MINT) analyses identified distinct discriminant taxa responsible for shaping the microbial communities in different-sized granules.},
}
@article {pmid32582081,
year = {2020},
author = {Wu, X and Zhang, S and Li, H and Shen, L and Dong, C and Sun, Y and Chen, H and Xu, B and Zhuang, W and Deighton, M and Qu, Y},
title = {Biofilm Formation of Candida albicans Facilitates Fungal Infiltration and Persister Cell Formation in Vaginal Candidiasis.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {1117},
pmid = {32582081},
issn = {1664-302X},
abstract = {Background: Vaginal candidiasis is an important medical condition awaiting more effective treatment. How Candida albicans causes this disease and survives antifungal treatment is not yet fully understood. This study aimed to establish a comprehensive understanding of biofilm-related defensive strategies that C. albicans uses to establish vaginal candidiasis and to survive antifungal treatment.<br><br>Methods: A mouse model of vaginal candidiasis was adopted to examine the formation of biotic biofilms on the vaginal epithelium and fungal infiltration by laboratory and clinical strains of C. albicans. Histopathological changes and local inflammation in the vaginal epithelium caused by C. albicans of different biofilm phenotypes were compared. Antifungal susceptibility testing was carried out for C. albicans grown as planktonic cells, microplate-based abiotic biofilms, and epithelium-based biotic biofilms. Formation of persister cells by C. albicans in different growth modes was also quantified and compared.<br><br>Results: C. albicans wild-type reference strains and clinical isolates, but not the biofilm-defective mutants, formed a significant number of biotic biofilms on the vaginal epithelium of mice and infiltrated the epithelium. Biofilm formation and epithelial invasion induced local inflammatory responses and histopathological changes in the vaginal epithelium including neutrophil infiltration and subcorneal microabscesses. Biofilm growth on the vaginal epithelium also led to high resistance to antifungal treatments and promoted the formation of antifungal-tolerant persister cells.<br><br>Conclusion: This study comprehensively assessed biofilm-related microbial strategies that C. albicans uses in vaginal candidiasis and provided experimental evidence to support the important role of biofilm formation in the histopathogenesis of vaginal candidiasis and the recalcitrance of the infection to antifungal treatment.},
}
@article {pmid32579104,
year = {2020},
author = {Choo, S and Borchert, E and Wiese, J and Saha, M and Künzel, S and Weinberger, F and Hentschel, U},
title = {Polaribacter septentrionalilitoris sp. nov., isolated from the biofilm of a stone from the North Sea.},
journal = {International journal of systematic and evolutionary microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1099/ijsem.0.004290},
pmid = {32579104},
issn = {1466-5034},
abstract = {A new member of the family Flavobacteriaceae was isolated from the biofilm of a stone at Nordstrand, a peninsula at the German North Sea shore. Phylogenetic analysis of the 16S rRNA gene sequence showed that strain ANORD1T was most closely related to the validly described type strains Polaribacter porphyrae LNM-20T (97.0 %) and Polaribacter reichenbachii KMM 6386T (96.9 % 16S rRNA gene sequence similarity) and clustered with Polaribacter gangjinensis K17-16T (96.0 %). Strain ANORD1T was determined to be mesophilic, Gram-negative, non-motile and strictly aerobic. Optimal growth was observed at 20-30 °C, within a salinity range of 2-7 % sea salt and from pH 7-10. Like other type strains of the genus Polaribacter, ANORD1T was tested negative for flexirubin-type pigments, while carotenoid-type pigments were detected. The DNA G+C content of strain ANORD1T was 30.6 mol%. The sole respiratory quinone detected was menaquinone 6 (MK-6). The major fatty acids identified were C15 : 0, iso-C15 : 0, C15 : 1 ω6c and iso-C15 : 0 3-OH. Based on the polyphasic approach, strain ANORD1T represents a novel species in the genus Polaribacter, with the name Polaribacter septentrionalilitoris sp. nov. being proposed. The type strain is ANORD1T (=DSM 110039T=NCIMB 15081T=MTCC 12685T).},
}
@article {pmid32578800,
year = {2020},
author = {Silva, AM and Miranda, LFB and AraÚjo, ASM and Prado JÚnior, RR and Mendes, RF},
title = {Electric toothbrush for biofilm control in individuals with Down syndrome: a crossover randomized clinical trial.},
journal = {Brazilian oral research},
volume = {34},
number = {},
pages = {e057},
doi = {10.1590/1807-3107bor-2020.vol34.0057},
pmid = {32578800},
issn = {1807-3107},
mesh = {Adolescent ; Adolescent Behavior ; *Biofilms ; Caregivers ; Child ; Child Behavior ; Cross-Over Studies ; Dental Caries/prevention &amp; control ; *Dental Devices, Home Care ; Dental Plaque/*prevention &amp; control ; Down Syndrome/*physiopathology ; Equipment Design ; Female ; Humans ; Male ; Statistics, Nonparametric ; Time Factors ; Toothbrushing/*instrumentation ; Treatment Outcome ; },
abstract = {Poor oral hygiene seems to be the norm in children and teenagers with Down Syndrome (DS). Advances in design and types of toothbrushes may improve biofilm control. This randomized, single-blind, crossover clinical trial evaluated the effectiveness of electric toothbrushes regarding mechanical control of biofilm in children and teenagers with DS and their cooperation. Twenty-nine participants with DS, aged 6 to 14 years, used both types of toothbrushes: electric (ET) and manual (MT). The order of use of the different types of toothbrushes was randomly defined, including a 7-day period with each type with 7-day washout period in between. The Turesky-Quigley-Hein biofilm index was used before and after brushing to assess the effectiveness of the technique. Frankl's behavioral scale was used during toothbrushing to assess the participants' cooperation. Paired T-test, Mann Whitney, Chi-square, and Fisher's Exact tests were applied, with a significance level of 5%. The quantity of dental biofilm was significantly reduced after both brushing techniques (p < 0.001). However, no significant difference was found in total biofilm (ET: 0.73 ± 0.36; MT: 0.73 ± 0.34; p = 0.985) or % biofilm reduction (ET: 72.22%; MT: 70.96%; p = 0.762) after brushing between techniques or in % biofilm reduction between toothbrushes of age groups (6 -9 years, p = 0.919; 10-14 years, p = 0.671). Participants showed similar cooperation level with the two types of toothbrush (p = 1.000). The use of electric or manual toothbrush had no effect on the quantity of dental biofilm removed in children and teenagers with DS, nor did it influence their cooperation during the procedure.},
}
@article {pmid32577899,
year = {2020},
author = {Bulut, F and Cumbul, A and Safak, AS},
title = {An analysis of the histomorphometric and clinical significance of mucosal biofilm in tonsil tissue of the children with a history of recurrent/chronic tonsillitis in both the mother and father.},
journal = {European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00405-020-06111-7},
pmid = {32577899},
issn = {1434-4726},
abstract = {PURPOSE: The aim of this study is to analyse the histomorphometric and clinical features of the mucosal biofilm in tonsil tissue of children with a history of recurrent/chronic tonsillitis in both the mother and father.<br><br>METHODS: This study enrolled 82 children (between 3 and 14 years of age). These children were divided into two main groups according to the present of recurrent/chronic tonsillitis. Patients in group 1 were divided into four subgroups (A, B, C, D) according to the history of recurrent/chronic tonsillitis in mother and/or father. 30 patients in group 1 were underwent tonsillectomy and the 52 patients in control group (2) have not had history of recurrent/chronic tonsillitis. To that end, among children with a history of recurrent/chronic tonsillitis certain changes in the volume and thickness of mucosal biofilm in tonsil tissue have been exhibited with respect to it is histomorphometric and clinical significance.<br><br>RESULTS: The children with a parental history of recurrent/chronic tonsillitis in group A, an increase in the thickness and volume of mucosal biofilm samples was detected according to the other subgroups (B, C, D). Parents history of group A patients statistically significant differences were detected with respect to halitosis symptoms, attack age of the first tonsillitis and resistant fever despite antibiotic treatment for children under the age of 3 years.<br><br>CONCLUSIONS: This study showed that children under the age of 3 years of age with a history of recurrent/chronic tonsillitis in both the mother and father, halitosis symptoms, attack age of the first tonsillitis and resistant fever despite antibiotic treatment are collectively linked.},
}
@article {pmid32576676,
year = {2020},
author = {Walsh, BJC and Wang, J and Edmonds, KA and Palmer, LD and Zhang, Y and Trinidad, JC and Skaar, EP and Giedroc, DP},
title = {The Response of Acinetobacter baumannii to Hydrogen Sulfide Reveals Two Independent Persulfide-Sensing Systems and a Connection to Biofilm Regulation.},
journal = {mBio},
volume = {11},
number = {3},
pages = {},
pmid = {32576676},
issn = {2150-7511},
support = {F32 AI122516/AI/NIAID NIH HHS/United States ; T32 GM109825/GM/NIGMS NIH HHS/United States ; R01 AI101171/AI/NIAID NIH HHS/United States ; R35 GM118157/GM/NIGMS NIH HHS/United States ; T32 GM131994/GM/NIGMS NIH HHS/United States ; K99 HL143441/HL/NHLBI NIH HHS/United States ; },
abstract = {Acinetobacter baumannii is an opportunistic nosocomial pathogen that is the causative agent of several serious infections in humans, including pneumonia, sepsis, and wound and burn infections. A. baumannii is also capable of forming proteinaceous biofilms on both abiotic and epithelial cell surfaces. Here, we investigate the response of A. baumannii toward sodium sulfide (Na2S), known to be associated with some biofilms at oxic/anoxic interfaces. The addition of exogenous inorganic sulfide reveals that A. baumannii encodes two persulfide-sensing transcriptional regulators, a primary σ54-dependent transcriptional activator (FisR), and a secondary system controlled by the persulfide-sensing biofilm growth-associated repressor (BigR), which is only induced by sulfide in a fisR deletion strain. FisR activates an operon encoding a sulfide oxidation/detoxification system similar to that characterized previously in Staphylococcus aureus, while BigR regulates a secondary persulfide dioxygenase (PDO2) as part of yeeE-yedE-pdo2 sulfur detoxification operon, found previously in Serratia spp. Global S-sulfuration (persulfidation) mapping of the soluble proteome reveals 513 persulfidation targets well beyond FisR-regulated genes and includes five transcriptional regulators, most notably the master biofilm regulator BfmR and a poorly characterized catabolite regulatory protein (Crp). Both BfmR and Crp are well known to impact biofilm formation in A. baumannii and other organisms, respectively, suggesting that persulfidation of these regulators may control their activities. The implications of these findings on bacterial sulfide homeostasis, persulfide signaling, and biofilm formation are discussed.IMPORTANCE Although hydrogen sulfide (H2S) has long been known as a respiratory poison, recent reports in numerous bacterial pathogens reveal that H2S and more downstream oxidized forms of sulfur collectedly termed reactive sulfur species (RSS) function as antioxidants to combat host efforts to clear the infection. Here, we present a comprehensive analysis of the transcriptional and proteomic response of A. baumannii to exogenous sulfide as a model for how this important human pathogen manages sulfide/RSS homeostasis. We show that A. baumannii is unique in that it encodes two independent persulfide sensing and detoxification pathways that govern the speciation of bioactive sulfur in cells. The secondary persulfide sensor, BigR, impacts the expression of biofilm-associated genes; in addition, we identify two other transcriptional regulators known or projected to regulate biofilm formation, BfmR and Crp, as highly persulfidated in sulfide-exposed cells. These findings significantly strengthen the connection between sulfide homeostasis and biofilm formation in an important human pathogen.},
}
@article {pmid32576670,
year = {2020},
author = {Béchon, N and Mihajlovic, J and Vendrell-Fernández, S and Chain, F and Langella, P and Beloin, C and Ghigo, JM},
title = {Capsular Polysaccharide Cross-Regulation Modulates Bacteroides thetaiotaomicron Biofilm Formation.},
journal = {mBio},
volume = {11},
number = {3},
pages = {},
pmid = {32576670},
issn = {2150-7511},
abstract = {Bacteroides thetaiotaomicron is one of the most abundant gut symbiont species, whose contribution to host health through its ability to degrade dietary polysaccharides and mature the immune system is under intense scrutiny. In contrast, adhesion and biofilm formation, which are potentially involved in gut colonization and microbiota structure and stability, have hardly been investigated in this intestinal bacterium. To uncover B. thetaiotaomicron biofilm-related functions, we performed a transposon mutagenesis in the poorly biofilm-forming reference strain VPI-5482 and showed that capsule 4, one of the eight B. thetaiotaomicron capsules, hinders biofilm formation. We then showed that the production of capsules 1, 2, 3, 5, and 6 also inhibits biofilm formation and that decreased capsulation of the population correlated with increased biofilm formation, suggesting that capsules could be masking adhesive surface structures. In contrast, we showed that capsule 8 displayed intrinsic adhesive properties. Finally, we demonstrated that BT2934, the wzx homolog of the B. thetaiotaomicron glycosylation locus, competes with capsule production and impacts its adhesion capacity. This study therefore establishes B. thetaiotaomicron capsule regulation as a major determinant of B. thetaiotaomicron biofilm formation, providing new insights into how modulation of different B. thetaiotaomicron surface structures affects in vitro biofilm formation.IMPORTANCE The human gut harbors a complex bacterial community that plays important roles in host health and disease, including nutrient acquisition, maturation of the immune system, and resistance to infections. The capacity to adhere to surfaces and form communities called biofilms is believed to be important for niche colonization and maintenance of gut bacteria. However, little is known about the adhesion capacity of most gut bacteria. In this study, we investigated biofilm formation in Bacteroides thetaiotaomicron, one of the most abundant bacteria of the normal mammalian intestine. We identified that B. thetaiotaomicron capsules, a group of eight surface-exposed polysaccharidic layers mediating important interactions with the gut environment, are also major determinants of biofilm formation that mask or unmask adhesion factors. Studying how B. thetaiotaomicron regulates its adhesion properties will allow us to better understand the physiology and specific properties of this important gut symbiont within anaerobic biofilms.},
}
@article {pmid32576653,
year = {2020},
author = {Simmons, EL and Bond, MC and Koskella, B and Drescher, K and Bucci, V and Nadell, CD},
title = {Biofilm Structure Promotes Coexistence of Phage-Resistant and Phage-Susceptible Bacteria.},
journal = {mSystems},
volume = {5},
number = {3},
pages = {},
pmid = {32576653},
issn = {2379-5077},
support = {P20 GM113132/GM/NIGMS NIH HHS/United States ; P30 DK117469/DK/NIDDK NIH HHS/United States ; R01 AI081838/AI/NIAID NIH HHS/United States ; },
abstract = {Encounters among bacteria and their viral predators (bacteriophages) are among the most common ecological interactions on Earth. These encounters are likely to occur with regularity inside surface-bound communities that microbes most often occupy in natural environments. Such communities, termed biofilms, are spatially constrained: interactions become limited to near neighbors, diffusion of solutes and particulates can be reduced, and there is pronounced heterogeneity in nutrient access and physiological state. It is appreciated from prior theoretical work that phage-bacteria interactions are fundamentally different in spatially structured contexts, as opposed to well-mixed liquid culture. Spatially structured communities are predicted to promote the protection of susceptible host cells from phage exposure, and thus weaken selection for phage resistance. The details and generality of this prediction in realistic biofilm environments, however, are not known. Here, we explore phage-host interactions using experiments and simulations that are tuned to represent the essential elements of biofilm communities. Our simulations show that in biofilms, phage-resistant cells-as their relative abundance increases-can protect clusters of susceptible cells from phage exposure, promoting the coexistence of susceptible and phage-resistant bacteria under a large array of conditions. We characterize the population dynamics underlying this coexistence, and we show that coexistence is recapitulated in an experimental model of biofilm growth measured with confocal microscopy. Our results provide a clear view into the dynamics of phage resistance in biofilms with single-cell resolution of the underlying cell-virion interactions, linking the predictions of canonical theory to realistic models and in vitro experiments of biofilm growth.IMPORTANCE In the natural environment, bacteria most often live in communities bound to one another by secreted adhesives. These communities, or biofilms, play a central role in biogeochemical cycling, microbiome functioning, wastewater treatment, and disease. Wherever there are bacteria, there are also viruses that attack them, called phages. Interactions between bacteria and phages are likely to occur ubiquitously in biofilms. We show here, using simulations and experiments, that biofilms will in most conditions allow phage-susceptible bacteria to be protected from phage exposure, if they are growing alongside other cells that are phage resistant. This result has implications for the fundamental ecology of phage-bacteria interactions, as well as the development of phage-based antimicrobial therapeutics.},
}
@article {pmid32576596,
year = {2020},
author = {Rodríguez López, AL and Lee, MR and Wang, NB and Dunn, KK and Sanchez, H and Raman, N and Andes, DR and Lynn, DM and Palecek, SP},
title = {Correction for Rodríguez López et al., &quot;Small-Molecule Morphogenesis Modulators Enhance the Ability of 14-Helical β-Peptides To Prevent Candida albicans Biofilm Formation&quot;.},
journal = {Antimicrobial agents and chemotherapy},
volume = {64},
number = {7},
pages = {},
doi = {10.1128/AAC.00841-20},
pmid = {32576596},
issn = {1098-6596},
}
@article {pmid32575628,
year = {2020},
author = {Singh, R and Dubey, AK},
title = {Isolation and Characterization of a New Endophytic Actinobacterium Streptomyces californicus Strain ADR1 as a Promising Source of Anti-Bacterial, Anti-Biofilm and Antioxidant Metabolites.},
journal = {Microorganisms},
volume = {8},
number = {6},
pages = {},
doi = {10.3390/microorganisms8060929},
pmid = {32575628},
issn = {2076-2607},
abstract = {In view of the fast depleting armamentarium of drugs against significant pathogens, like methicillin-resistant Staphylococcus aureus (MRSA) and others due to rapidly emerging drug-resistance, the discovery and development of new drugs need urgent action. In this endeavor, a new strain of endophytic actinobacterium was isolated from the plant Datura metesl, which produced secondary metabolites with potent anti-infective activities. The isolate was identified as Streptomyces californicus strain ADR1 based on 16S rRNA gene sequence analysis. Metabolites produced by the isolate had been investigated for their antibacterial attributes against important pathogens: S. aureus, MRSA, S. epidermis, Enterococcus faecium and E. faecalis. Minimum inhibitory concentration (MIC90) values against these pathogens varied from 0.23 ± 0.01 to 5.68 ± 0.20 μg/mL. The metabolites inhibited biofilm formation by the strains of S. aureus and MRSA (Biofilm inhibitory concentration [BIC90] values: 0.74 ± 0.08-4.92 ± 0.49 μg/mL). The BIC90 values increased in the case of pre-formed biofilms. Additionally, the metabolites possessed good antioxidant properties, with an inhibitory concentration (IC90) value of 217.24 ± 6.77 µg/mL for 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging. An insight into different classes of compounds produced by the strain ADR1 was obtained by chemical profiling and GC-MS analysis, wherein several therapeutic classes, for example, alkaloids, phenolics, terpenes, terpenoids and glycosides, were discovered.},
}
@article {pmid32574911,
year = {2020},
author = {Ma, Y and Zhang, Z and Nitin, N and Sun, G},
title = {Integration of photo-induced biocidal and hydrophilic antifouling functions on nanofibrous membranes with demonstrated reduction of biofilm formation.},
journal = {Journal of colloid and interface science},
volume = {578},
number = {},
pages = {779-787},
doi = {10.1016/j.jcis.2020.06.037},
pmid = {32574911},
issn = {1095-7103},
abstract = {Survival and pathogenic microbial adhesions on surfaces of materials followed by the formation of biofilms with robust resistance to antibiotics constitute the forefront of disease transmissions. Conventional strategies responding to this challenge are rather limited due to the biofouling effect of microorganisms or the irreversible consumption of antimicrobial agents embedded into the materials. Herein, we report an approach of combining photo-induced rechargeable biocidal properties with microbial resisting and releasing zwitterionic hydrophilic functions on surfaces of materials to improve antifouling performances. Poly(vinyl alcohol-co-ethylene) (EVOH) nanofibrous membranes (NFMs) were chemically incorporated with both 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BPTCD), a photoactive chemical, and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), a zwitterionic monomer. Both functional agents work independently and construct concerted microbial resisting, killing, and releasing functions to reduce microbial contamination and biofilm formation. The resulted SBMA@EVOH NFMs exhibited integrated features of large ROS production capacity, ease of photoactive rechargeability and controllability, long-term stability, high biocidal efficacy (>99.9999% via contact killing), and promising antifouling performance, which enable the SBMA@EVOH NFMs to serve as a biocidal material for food safety and medical applications.},
}
@article {pmid32574876,
year = {2020},
author = {Yuan, K and Li, S and Zhong, F},
title = {Treatment of coking wastewater in biofilm-based bioaugmentation process: Biofilm formation and microbial community analysis.},
journal = {Journal of hazardous materials},
volume = {400},
number = {},
pages = {123117},
doi = {10.1016/j.jhazmat.2020.123117},
pmid = {32574876},
issn = {1873-3336},
abstract = {Coking wastewater (CWW) containing complicated organic compositions and strong toxicity cause potential hazards to natural water bodies as well as human health. The aim of this study was integrating newly isolated Comamonas sp. ZF-3, biofilm-based bioaugmentation and fluidized bed reactor into an anoxic filter-fluidized bed reactor (AF-FBR) system to treat actual CWW. The results showed that 93 % of chemical oxygen demand (COD) and 97 % of ammonia nitrogen (NH4+-N) removal efficiency were achieved with hydraulic retention time of 70 h. The main pollutants including phenolic compounds, heterocyclic compounds and polycyclic aromatic hydrocarbons could be removed via biofilm-based process in AF-FBR. The formation of carrier biofilm was consistent with the system performance as well as the biofilm community evolution, during which the microbial community was gradually dominated by some functional genus (e.g., Comamonas, Thiobacillus, Pseudomonas and Thauera), meanwhile, ammonium-oxidizing bacteria Nitrosomonas, nitrite-oxidizing bacteria Nitrospira and denitrifiers (e.g., Pseudomonas, Thiobacillus and Bacillus) coexisted in biofilm to form a microbial community for biological nitrogen removal. Such microbial community structure explained the observed simultaneous removal of COD and NH4+-N in the AF-FBR.},
}
@article {pmid32573275,
year = {2020},
author = {Díaz, MA and González, SN and Alberto, MR and Arena, ME},
title = {Human probiotic bacteria attenuate Pseudomonas aeruginosa biofilm and virulence by quorum-sensing inhibition.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-13},
doi = {10.1080/08927014.2020.1783253},
pmid = {32573275},
issn = {1029-2454},
abstract = {This work investigated chloroform extracts from culture supernatants of two human probiotic bacteria, Lactobacillus casei CRL 431 and Lactobacillus acidophilus CRL 730 for the production of virulence factors and quorum sensing (QS) interference against three Pseudomonas aeruginosa strains. Both extracts inhibited biofilm biomass (up to 50%), biofilm metabolic activity (up to 39%), the production of the enzyme elastase (up to 63%) and pyocyanin (up to 77%), and decreased QS, without presenting any antibacterial acgivity. In addition, the chloroform extracts of both strains disrupted preformed biofilms of the three strains of P. aeruginosa analyzed (up to 40%). GC-MS analysis revealed that the major compounds detected in the bioactive extracts were four diketopiperazines. This study suggests that the metabolites of L. casei and L. acidophilus could be a promising alternative to combat the pathogenicity of P. aeruginosa.},
}
@article {pmid32571216,
year = {2020},
author = {Szerencsés, B and Igaz, N and Tóbiás, Á and Prucsi, Z and Rónavári, A and Bélteky, P and Madarász, D and Papp, C and Makra, I and Vágvölgyi, C and Kónya, Z and Pfeiffer, I and Kiricsi, M},
title = {Size-dependent activity of silver nanoparticles on the morphological switch and biofilm formation of opportunistic pathogenic yeasts.},
journal = {BMC microbiology},
volume = {20},
number = {1},
pages = {176},
pmid = {32571216},
issn = {1471-2180},
support = {GINOP-2.3.2-15-2016-00035//Hungarian Government and European Union/ ; GINOP-2.3.2-15-2016-00038//Hungarian Goverment and European Union/ ; UNKP-18-3-I-SZTE-42//Hungarian Ministry of Technology and Innovation/ ; },
abstract = {BACKGROUND: Dimorphism and biofilm formation are important virulence factors of some opportunistic human pathogenic yeasts. Such species commensally colonize skin or mucosal surfaces generally in yeast form, but under particular circumstances, convert into virulent hyphae and disseminate internal organs or cause mucocutaneous infections. The yeast-to-hypha shape-conversion promotes the development of a biofilm, a thick extracellular matrix with sessile cells within. The biofilm is capable to prevent the penetration of antifungal drugs, rendering the surviving biofilm-resident cells intrinsic sources of recurrent infections. The aim of this study was to evaluate the ability of silver nanoparticles (AgNPs) to attenuate the morphological switch and biofilm formation of several opportunistic pathogenic yeasts and to determine whether this feature depends on the nanoparticle size.<br><br>RESULTS: AgNPs in three different sizes were prepared by chemical reduction approach and characterized by transmission electron microscopy, ultraviolet-visible spectroscopy and dynamic light scattering. The antifungal activity was evaluated by the microdilution method, the inhibitory capacity on biofilm formation and the biofilm degradation ability of differently sized AgNPs was assessed by viability assay. The morphological state of opportunistic pathogenic yeast cells in monoculture and in co-culture with human keratinocytes in the presence of AgNPs was examined by flow cytometry and scanning electron microscopy. All the three AgNPs inhibited the growth of the examined opportunistic pathogenic yeasts, nevertheless, AgNPs with the smallest diameter exhibited the most prominent toxic activities. AgNPs attenuated the biofilm formation in a nanoparticle size-dependent manner; however, their biofilm destruction capacity was negligible. AgNPs with the smallest size exerted the most significant effect on suppressing the morphological change of pathogens in monoculture as well as in a co-culture with keratinocytes.<br><br>CONCLUSIONS: Our results confirm that AgNPs are capable to hinder yeast-to-hypha morphological conversion and biofilm formation of opportunistic pathogens and this biological effect of AgNPs is size-dependent.},
}
@article {pmid32570785,
year = {2020},
author = {Jeon, BK and Lee, CH and Kim, AR and Han, SH and Kim, HJ and Antonson, SA and Kim, SY},
title = {Effect of Etching Procedures on the Adhesion of Biofilm-Coated Dentin.},
journal = {Materials (Basel, Switzerland)},
volume = {13},
number = {12},
pages = {},
doi = {10.3390/ma13122762},
pmid = {32570785},
issn = {1996-1944},
support = {2017M3A9E4047246//National Research Foundation of Korea/ ; NRF-2018R1A5A2024418//National Research Foundation of Korea/ ; },
abstract = {Oral biofilms coat all surfaces in the oral cavity including the exposed dentin surface. This study aimed to investigate biofilm removal by acid etching procedures and the effects of the residual biofilm on dentin surfaces on composite-dentin adhesion. Dentin discs were assigned to five groups: no biofilm formation (C); biofilm formation and no surface treatment (BF); biofilm formation and acid etching (BF-E); biofilm formation and acid etching followed by chlorhexidine soaking (BF-EC); and biofilm formation and rubbing with pumice, followed by acid etching (BF-RE). Biofilms were formed on saliva-precoated dentin discs by soaking the discs in Streptococcus mutans (S. mutans) suspension. Biofilm removal from the dentin surface was evaluated quantitatively and qualitatively by confocal laser scanning microscopy and scanning electron microscopy, respectively. To compare the bond strength of the biofilm-coated dentin discs with the surface treatments, specimens were assigned to four groups: no biofilm formation and acid etching (C-E); BF-E; BF-EC; and BF-RE. Assessments of the micro-shear bond strength and subsequent failure modes were performed. BF-E and BF-EC did not remove the biofilm, whereas BF-RE partially removed the biofilm attached to the dentin (p < 0.05). The bond strength of BF-RE was significantly higher than those of BF-E and BF-EC, but lower than that of C-E (p < 0.05). In conclusion, mechanical biofilm removal is recommended before etching procedures to enhance adhesion to the biofilm-coated dentin.},
}
@article {pmid32570081,
year = {2020},
author = {Zhao, L and Wang, Z and Ren, HY and Nan, J and Chen, C and Ren, NQ},
title = {Improving biogas upgrading and liquid chemicals production simultaneously by a membrane biofilm reactor.},
journal = {Bioresource technology},
volume = {313},
number = {},
pages = {123693},
doi = {10.1016/j.biortech.2020.123693},
pmid = {32570081},
issn = {1873-2976},
abstract = {In this study, a novel membrane biofilm reactor (MBfR) was developed for simultaneously biogas upgrading and liquid chemicals production. With external hydrogen supplied from inside of the gas permeable hollow fiber of the MBfR, CO2 in biogas could be captured via a biological process as liquid chemicals and simultaneously producing high-purity methane. Continuous operation of MBfR further confirmed that higher solubilized hydrogen was favorably affecting acetate and ethanol titer and rate, and methane purity. Moreover, by retaining biomass on the outer surface of hollow fiber, the highest biogas purity (96.7%) and acetate and ethanol production rates (37.8 and 13.5 mmol L-1d-1) were achieved at a hydraulic retention time of 2.0 d. Meanwhile, the CO2 and hydrogen conversion efficiency reached to the maximum of 93.8% and 98.1%, respectively. The findings obtained can pave a new way for efficient liquid chemical production and biogas upgrading with both economic and environmental benefits.},
}
@article {pmid32569817,
year = {2020},
author = {Vargas-Straube, MJ and Beard, S and Norambuena, R and Paradela, A and Vera, M and Jerez, CA},
title = {High copper concentration reduces biofilm formation in Acidithiobacillus ferrooxidans by decreasing production of extracellular polymeric substances and its adherence to elemental sulfur.},
journal = {Journal of proteomics},
volume = {225},
number = {},
pages = {103874},
doi = {10.1016/j.jprot.2020.103874},
pmid = {32569817},
issn = {1876-7737},
abstract = {Acidithiobacillus ferrooxidans is an acidophilic bacterium able to grow in environments with high concentrations of metals. It is a chemolithoautotroph able to form biofilms on the surface of solid minerals to obtain its energy. The response of both planktonic and sessile cells of A. ferrooxidans ATCC 23270 grown in elemental sulfur and adapted to high copper concentration was analyzed by quantitative proteomics. It was found that 137 proteins varied their abundance when comparing both lifestyles. Copper effllux proteins, some subunits of the ATP synthase complex, porins, and proteins involved in cell wall modification increased their abundance in copper-adapted sessile lifestyle cells. On the other hand, planktonic copper-adapted cells showed increased levels of proteins such as: cupreredoxins involved in copper cell sequestration, some proteins related to sulfur metabolism, those involved in biosynthesis and transport of lipopolysaccharides, and in assembly of type IV pili. During copper adaptation a decreased formation of biofilms was measured as determined by epifluorescence microscopy. This was apparently due not only to a diminished number of sessile cells but also to their exopolysaccharides production. This is the first study showing that copper, a prevalent metal in biomining environments causes dispersion of A. ferrooxidans biofilms. SIGNIFICANCE: Copper is a metal frequently found in high concentrations at mining environments inhabitated by acidophilic microorganisms. Copper resistance determinants of A. ferrooxidans have been previously studied in planktonic cells. Although biofilms are recurrent in these types of environments, the effect of copper on their formation has not been studied so far. The results obtained indicate that high concentrations of copper reduce the capacity of A. ferrooxidans ATCC 23270 to form biofilms on sulfur. These findings may be relevant to consider for a bacterium widely used in copper bioleaching processes.},
}
@article {pmid32569709,
year = {2020},
author = {Kotian, A and Aditya, V and Jazeela, K and Karunasagar, I and Karunasagar, I and Deekshit, VK},
title = {Effect of bile on growth and biofilm formation of non-typhoidal salmonella serovars isolated from seafood and poultry.},
journal = {Research in microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.resmic.2020.06.002},
pmid = {32569709},
issn = {1769-7123},
abstract = {Bacterial cells adopt various strategies to adapt themselves in diverse environmental conditions. Salmonella is one such bacteria with diverse mechanisms to survive, replicate and infect in wide host range. This study aims at investigating the biofilm-forming ability of multidrug-resistant and sensitive Salmonella serovars on exposure to bile. Antibiogram of all the isolates was determined by disk diffusion method and their biofilm-forming ability in the presence or absence of bile was assessed by microtiter plate assay. Biofilm results were validated by calcofluor, Congo red plate and test tube method. Few isolates were selected for further study of their expression of biofilm related genes on exposure to bile using real time PCR. Among the 59 isolates of Salmonella isolated from seafood and poultry, 30 isolates were multi-drug resistant (MDR). Under control conditions, 57% (n = 25) of the serovars were able to form biofilm. While, 86% (n = 51) of the serovars produced biofilm in the presence of bile. The relative gene expression study of the selected serovars for 8 different genes showed a striking difference in the expression levels, supporting the hypothesis that the presence of bile triggers biofilm formation in food associated strains of non-typhoidal Salmonella by upregulation of genes involved in biofilm production.},
}
@article {pmid32569268,
year = {2020},
author = {Foster, CE and Kok, M and Flores, AR and Minard, CG and Luna, RA and Lamberth, LB and Kaplan, SL and Hulten, KG},
title = {Adhesin genes and biofilm formation among pediatric Staphylococcus aureus isolates from implant-associated infections.},
journal = {PloS one},
volume = {15},
number = {6},
pages = {e0235115},
pmid = {32569268},
issn = {1932-6203},
abstract = {BACKGROUND: Microbial surface component recognizing adhesive matrix molecules (MSCRAMMs) facilitate Staphylococcus aureus adherence to host tissue. We hypothesized that S. aureus isolates from implant-associated infections (IAIs) would differ in MSCRAMM profile and biofilm formation in vitro compared to skin and soft tissue infection (SSTI) isolates.<br><br>METHODS: Pediatric patients and their isolates were identified retrospectively. IAI and SSTI isolates were matched (1:4). Pulsed field gel electrophoresis was performed to group isolates as USA300 vs. non-USA300. Whole genome sequencing was performed and raw sequence data were interrogated for presence of MSCRAMMs (clfA, clfB, cna, ebh, efb, fnbpA, fnbpB, isdA, isdB, sdrC, sdrD, sdrE), biofilm-associated (icaA,D,B,C), and Panton-Valentine leukocidin (lukSF-PV) genes, accessory gene regulator group, and multilocus sequence types. In vitro biofilm formation was assessed for 47 IAI and 47 SSTI isolates using a microtiter plate assay. Conditional logistic regression was performed for analysis of matched data (STATA11, College Station, TX).<br><br>RESULTS: Forty-seven IAI and 188 SSTI isolates were studied. IAI isolates were more often methicillin susceptible S. aureus and non-USA300 vs. SSTI isolates [34 (72%) vs. 79 (42%), p = 0.001 and 38 (81%) vs. 57 (30%) p <0.001, respectively]. Greater than 98% of isolates carried clfA, clfB, efb, isdA, isdB, and icaA,D,B,C while cna was more frequently found among IAI vs. SSTI isolates (p = 0.003). Most isolates were strong biofilm producers.<br><br>CONCLUSIONS: S. aureus IAI isolates were significantly more likely to be MSSA and non-USA300 than SSTI isolates. Carriage of MSCRAMMs and biofilm formation did not differ significantly between isolates. Evaluation of genetic polymorphisms and gene expression profiles are needed to further delineate the role of adhesins in the pathogenesis of IAIs.},
}
@article {pmid32567865,
year = {2020},
author = {Zhang, Y and Pan, X and Liao, S and Jiang, C and Wang, L and Tang, Y and Wu, G and Dai, G and Chen, L},
title = {Quantitative proteomics reveals the mechanism of silver nanoparticles against multidrug-resistant Pseudomonas aeruginosa biofilm.},
journal = {Journal of proteome research},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.jproteome.0c00114},
pmid = {32567865},
issn = {1535-3907},
abstract = {The decline of clinical effective antibiotics has made it necessary to develop more effective antimicrobial agents, especially for refractory biofilm-related infections. Silver nanoparticles (AgNPs) are a new type of antimicrobial agent that can eradicate biofilms and reduce bacterial resistance, but its anti-biofilm mechanism has not been elucidated. In this study, we investigated the molecular mechanism of AgNPs against multidrug-resistant Pseudomonas aeruginosa by means of anti-biofilm tests, scanning electron microscope (SEM), and the Tandem Mass Tag (TMT)-labeled quantitative proteomics. Results of anti-biofilm demonstrated that AgNPs inhibited the formation of P. aeruginosa biofilm and disrupted its preformed biofilm. SEM showed that when exposed to AgNPs, the structure of P. aeruginosa biofilm was destroyed, along with significant reduction of its biomass. TMT-labeled quantitative proteomic analysis revealed that that AgNPs could defeat P. aeruginosa biofilm in multiple ways by inhibiting its adhesion and motility, stimulating strong oxidative stress response, destroying iron homeostasis, blocking aerobic and anaerobic respirations, and affecting quorum sensing (QS) systems. Our findings offer a new insight into clarifying the mechanism of AgNPs against biofilm, thus provide a theoretical basis for its clinical application.},
}
@article {pmid32566535,
year = {2020},
author = {Azam, MW and Zuberi, A and Khan, AU},
title = {bolA gene involved in curli amyloids and fimbriae production in E. coli: exploring pathways to inhibit biofilm and amyloid formation.},
journal = {Journal of biological research (Thessalonike, Greece)},
volume = {27},
number = {},
pages = {10},
pmid = {32566535},
issn = {1790-045X},
abstract = {Background: Biofilm formation is a complex phenomenon of bacterial cells, involved in several human infections. Its formation is regulated and controlled by several protein factors. The BolA-like proteins (bolA gene) are conserved in both prokaryotes and eukaryotes. The BolA protein is a transcription factor involved in bacterial cell motility and biofilm formation. This study was initiated to elucidate the role of the bolA gene in the curli biogenesis and amyloid production as well as to observe changes in the expression of fimH, a fimbriae gene.<br><br>Methods: Knockdown mutants of Escherichia coli MG1655 bolA gene (bolA-KD) were generated using CRISPR interference. The results obtained, were validated through gene expression using RT-PCR, microscopic analysis and different biofilm and amyloid assays.<br><br>Results: The bolA knockdown mutants showed a decrement in curli amyloid fibers, in fimbriae production and biofilm formation. We have also observed a reduction in EPS formation, eDNA production and extracellular protein content. Gene expression data showed that bolA downregulation caused the suppression of csgA and csgD of curli that led to the reduction in curli fiber and the amyloid formation and also the suppression of fimH, leading to the loss of fimbriae.<br><br>Conclusions: Curli fibers and fimbriae are found to be involved in biofilm formation leading to the pathogenicity of the bacterial cell. BolA is a conserved protein and is found to play a significant role in curli and fimbriae formation in E. coli. This study further proved that CRISPRi mediated suppression of the bolA gene leads to inhibition of biofilm formation through curli and fimbriae inhibition. Hence, it may be proposed as a possible target for intervention of biofilm mediated infections.},
}
@article {pmid32566142,
year = {2020},
author = {Hashimoto, A and Miyamoto, H and Kobatake, T and Nakashima, T and Shobuike, T and Ueno, M and Murakami, T and Noda, I and Sonohata, M and Mawatari, M},
title = {The combination of silver-containing hydroxyapatite coating and vancomycin has a synergistic antibacterial effect on methicillin-resistant Staphylococcus aureus biofilm formation.},
journal = {Bone &amp; joint research},
volume = {9},
number = {5},
pages = {211-218},
pmid = {32566142},
issn = {2046-3758},
abstract = {Aims: Biofilm formation is intrinsic to prosthetic joint infection (PJI). In the current study, we evaluated the effects of silver-containing hydroxyapatite (Ag-HA) coating and vancomycin (VCM) on methicillin-resistant Staphylococcus aureus (MRSA) biofilm formation.<br><br>Methods: Pure titanium discs (Ti discs), Ti discs coated with HA (HA discs), and 3% Ag-HA discs developed using a thermal spraying were inoculated with MRSA suspensions containing a mean in vitro 4.3 (SD 0.8) x 106 or 43.0 (SD 8.4) x 105 colony-forming units (CFUs). Immediately after MRSA inoculation, sterile phosphate-buffered saline or VCM (20 µg/ml) was added, and the discs were incubated for 24 hours at 37°C. Viable cell counting, 3D confocal laser scanning microscopy with Airyscan, and scanning electron microscopy were then performed. HA discs and Ag HA discs were implanted subcutaneously in vivo in the dorsum of rats, and MRSA suspensions containing a mean in vivo 7.2 (SD 0.4) x 106 or 72.0 (SD 4.2) x 105 CFUs were inoculated on the discs. VCM was injected subcutaneously daily every 12 hours followed by viable cell counting.<br><br>Results: Biofilms that formed on HA discs were thicker and larger than those on Ti discs, whereas those on Ag-HA discs were thinner and smaller than those on Ti discs. Viable bacterial counts in vivo revealed that Ag-HA combined with VCM was the most effective treatment.<br><br>Conclusion: Ag-HA with VCM has a potential synergistic effect in reducing MRSA biofilm formation and can thus be useful for preventing and treating PJI.Cite this article:Bone Joint Res. 2020;9(5):211-218.},
}
@article {pmid32564705,
year = {2020},
author = {Higgins, M and Zhang, L and Ford, R and Brownlie, J and Kleidon, T and Rickard, CM and Ullman, A},
title = {The microbial biofilm composition on peripherally inserted central catheters: A comparison of polyurethane and hydrophobic catheters collected from paediatric patients.},
journal = {The journal of vascular access},
volume = {},
number = {},
pages = {1129729820932423},
doi = {10.1177/1129729820932423},
pmid = {32564705},
issn = {1724-6032},
abstract = {BACKGROUND: Peripherally inserted central catheters are susceptible to microbial colonisation and subsequent biofilm formation, leading to central line-associated bloodstream infection, a serious peripherally inserted central catheter-related complication. Next-generation peripherally inserted central catheter biomaterials, such as hydrophobic materials (e.g. Endexo®), may reduce microbial biofilm formation or attachment, consequently reducing the potential for central line-associated bloodstream infection.<br><br>METHODS: Within a randomised controlled trial, culture-dependent and culture-independent methods were used to determine if the biomaterials used in traditional polyurethane peripherally inserted central catheters and hydrophobic peripherally inserted central catheters impacted microbial biofilm composition. This study also explored the impact of other clinical characteristics including central line-associated bloodstream infection, antibiotic therapy and dwell time on the microbial biofilm composition of peripherally inserted central catheters.<br><br>RESULTS: From a total of 32 patients, one peripherally inserted central catheter was determined to be colonised with Staphylococcus aureus, and on further analysis, the patient was diagnosed with central line-associated bloodstream infection. All peripherally inserted central catheters (n = 17 polyurethane vs n = 15 hydrophobic) were populated with complex microbial communities, including peripherally inserted central catheters considered non-colonised. The two main microbial communities observed included Staphylococcus spp., dominant on the colonised peripherally inserted central catheter, and Enterococcus, dominant on non-colonised peripherally inserted central catheters. Both the peripherally inserted central catheter biomaterial design and antibiotic therapy had no significant impact on microbial communities. However, the diversity of microbial communities significantly decreased with dwell time.<br><br>CONCLUSION: More diverse pathogens were present on the colonised peripherally inserted central catheter collected from the patient with central line-associated bloodstream infection. Microbial biofilm composition did not appear to be affected by the design of peripherally inserted central catheter biomaterials or antibiotic therapy. However, the diversity of the microbial communities appeared to decrease with dwell time.},
}
@article {pmid32564255,
year = {2020},
author = {Tak, S and Tiwari, A and Vellanki, BP},
title = {Correction to: Identification of emerging contaminants and their transformation products in a moving bed biofilm reactor (MBBR)-based drinking water treatment plant around River Yamuna in India.},
journal = {Environmental monitoring and assessment},
volume = {192},
number = {7},
pages = {445},
doi = {10.1007/s10661-020-08381-4},
pmid = {32564255},
issn = {1573-2959},
abstract = {The original version of this article unfortunately contains mistakes introduced during the production phase. Figures 7, 8, and 10 were incorrectly captured.},
}
@article {pmid32562967,
year = {2020},
author = {Zhang, L and Fu, G and Zhang, Z},
title = {Long-term stable and energy-neutral mixed biofilm electrode for complete nitrogen removal from high-salinity wastewater: Mechanism and microbial community.},
journal = {Bioresource technology},
volume = {313},
number = {},
pages = {123660},
doi = {10.1016/j.biortech.2020.123660},
pmid = {32562967},
issn = {1873-2976},
abstract = {The steady mixed biofilm electrode (MBE) was investigated for the removal of nitrogen from mustard tuber wastewater. Results showed that complete nitrogen removal occurred over a wide initial chemical oxygen demand (COD)/total nitrogen (TN) ratio ranging from 2.8 to 9.8 using MBE. MBE revealed broad-spectrum applicability for the treatment of high-salinity wastewater containing different forms of nitrogen. Bio-electrochemical process, in-situ heterotrophic nitrogen reduction, ammonia stripping, nitrogen assimilation, and endogenous denitrification coexisted for the removal of nitrogen. Batch activity tests and functional microorganism analysis confirmed that autotrophic/heterotrophic nitrification, anoxic/aerobic denitrification, and nitrogen bio-electrochemical reduction cooperated to achieve efficient nitrogen conversion. More importantly, the analysis of the preliminary energy balance demonstrated that MBE was self-sustaining. The long-term operation stability of MBE was of great importance for its practical application. The results provided herein offer new insights into bioelectrochemical nitrogen removal and resource treatment of high-salinity wastewater.},
}
@article {pmid32562809,
year = {2020},
author = {Moralez, AP and Perini, HF and Paulo, EA and Furlaneto-Maia, L and Furlaneto, MC},
title = {Effect of phenotypic switching on biofilm traits in Candida tropicalis.},
journal = {Microbial pathogenesis},
volume = {149},
number = {},
pages = {104346},
doi = {10.1016/j.micpath.2020.104346},
pmid = {32562809},
issn = {1096-1208},
abstract = {Candida tropicalis can undergo multiple forms of phenotypic switching. We have reported a switching system in C. tropicalis that is associated with changes in virulence attributes. We aimed to assess biofilm formation by distinct switch states of C. tropicalis and evaluate whether their sessile cells exhibit altered virulence traits. C. tropicalis strains included the parental phenotype (a clinical isolate) and four switch phenotypes (crepe, rough, revertant of crepe and revertant of rough). Biofilm formation and adhesion capability of sessile cells on polystyrene were assessed through quantification of total biomass. Filamentous forms were characterized by direct counting of sessile cells. A virulence assay was conducted using the Galleria mellonella infection model. Switch variants (crepe and rough) and their revertant counterparts produced higher biofilm biomass (P < 0.05) than the parental strain. Additionally, filamentous forms were enriched among sessile cells of switched strains compared to those observed for sessile cells of the parental strain, with the exception of the revertant of rough. Sessile cells of switched strains showed higher adhesion to polystyrene compared to the parental strain. Sessile cells of the crepe variant and its revertant strain (RC) exhibited higher virulence against G. mellonella larvae than sessile cells of the parental strain. Our findings indicate that switching events in C. tropicalis affect biofilm development and that sessile cells of distinct switch states may exhibit increased adhesion ability and enhanced virulence towards G. mellonella larvae.},
}
@article {pmid32561585,
year = {2020},
author = {Cai, W and Liu, W and Wang, B and Yao, H and Guadie, A and Wang, A},
title = {Semi-quantitative detection of hydrogen-associated or -free electron transfer within methanogenic biofilm of microbial electrosynthesis.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.01056-20},
pmid = {32561585},
issn = {1098-5336},
abstract = {Hydrogen-entangled electron transfer is verified as an important extracellular pathway of sharing reducing equivalents to regulate biofilm activities within the diversely anaerobic environment, especially in microbial electrosynthesis system. However, the lack of useful methods for in-situ hydrogen detection in cathodic biofilm, the role of hydrogen involved in electron transfer is still debatable. Herein, the cathodic biofilm was constructed in the CH4-produced microbial electrosynthesis reactors, in which the hydrogen evolution dynamic was analyzed to confirm the presence of hydrogen-associated electron transfer nearby the cathode within the micrometre scale. The fluorescent in-situ hybridization images indicated that a colocalized community of archaea and bacteria developed within the thick of biofilm 58.10 μm at cathode suggesting the hydrogen gradient detected by microsensor was consumed by the collaboration of bacteria and archaea. Coupling microsensor and cyclic voltammetry test further provided the semi-quantitative results of hydrogen-associated contribution to methane generation (around 21.20% ± 1.57% having a potential of -0.5 V to 0.69 V). This finding provides deep insight into the mechanism of electron transfer in biofilm on conductive materials.IMPORTANCE: Electron transfer from the electrode to biofilm is of great interest to the fields of microbial electrochemical technology, bioremediation and methanogenesis. It has promising application potential to boost more value-added products or pollutant degradation. Importantly, the microbial ability to obtain electrons from electrode and utilizing it brings a new insight into the direct interspecies electron transfer during methanogenesis. Previous studies had verified the direct pathway of electron transfer from the electrode to the pure-culture bacterium, but it was rarely reported how the methanogenic biofilm of mixed cultures shares electrons by hydrogen-associated or hydrogen-free pathway. In the current study, a combination method of microsensor and cyclic voltammetry successfully semi-quantified the role of hydrogen in the electron transfer from the electrode to methanogenic biofilm.},
}
@article {pmid32560415,
year = {2020},
author = {Pannella, G and Lombardi, SJ and Coppola, F and Vergalito, F and Iorizzo, M and Succi, M and Tremonte, P and Iannini, C and Sorrentino, E and Coppola, R},
title = {Effect of Biofilm Formation by Lactobacillus plantarum on the Malolactic Fermentation in Model Wine.},
journal = {Foods (Basel, Switzerland)},
volume = {9},
number = {6},
pages = {},
doi = {10.3390/foods9060797},
pmid = {32560415},
issn = {2304-8158},
abstract = {Biofilm life-style of Lactobacillus plantarum (L. plantarum) strains was evaluated in vitro as a new and suitable biotechnological strategy to assure L-malic acid conversion in wine stress conditions. Sixty-eight L. plantarum strains isolated from diverse sources were assessed for their ability to form biofilm in acid (pH 3.5 or 3.2) or in ethanol (12% or 14%) stress conditions. The effect of incubation times (24 and 72 h) on the biofilm formation was evaluated. The study highlighted that, regardless of isolation source and stress conditions, the ability to form biofilm was strain-dependent. Specifically, two clusters, formed by high and low biofilm producer strains, were identified. Among high producer strains, L. plantarum Lpls22 was chosen as the highest producer strain and cultivated in planktonic form or in biofilm using oak supports. Model wines at 12% of ethanol and pH 3.5 or 3.2 were used to assess planktonic and biofilm cells survival and to evaluate the effect of biofilm on L-malic acid conversion. For cells in planktonic form, a strong survival decay was detected. In contrast, cells in biofilm life-style showed high resistance, assuring a prompt and complete L-malic acid conversion.},
}
@article {pmid32560399,
year = {2020},
author = {Fu, Y and An, Q and Cheng, Y and Yang, Y and Wang, L and Zhang, H and Ge, Y and Li, D and Zhang, Y},
title = {A Textile Pile Debridement Material Consisting of Polyester Fibers for in Vitro Removal of Biofilm.},
journal = {Polymers},
volume = {12},
number = {6},
pages = {},
doi = {10.3390/polym12061360},
pmid = {32560399},
issn = {2073-4360},
support = {51803095//National Natural Science Foundation of China/ ; BK20190927//Natural Science Foundation of Jiangsu Province/ ; 2019Z104//Postdoctoral Daily Program of Jiangsu Province/ ; MS12018005//Nantong Science and Technology Project/ ; W201905//Open Project Program of Key Laboratory of Textile Science &amp; Technology (Donghua University), Ministry of Education/ ; },
abstract = {Biofilms formed on skin wound lead to inflammation and a delay of healing. In the present work, a novel textile pile debridement material was prepared and treated by plasma. Samples before and after plasma treatment were characterized by a series of methods, including scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and water uptake capacity. Besides, mechanical, coagulation, and in vitro biofilm removal performances of the textile pile debridement material were evaluated, with a medical gauze as a control. The results demonstrate that the plasma treatment produced corrosions and oxygen-containing polar groups on the fiber surface, offering an enhanced water uptake capacity of the textile pile debridement material. In addition, compressive tests certify the mechanical performances of the textile pile debridement material in both dry and wet conditions. The results from a kinetic clotting time test suggest a favorable ability to promote blood coagulation. Furthermore, the results of an MTT cell viability assay, SEM, and confocal laser scanning microscopy (CLSM) illustrate that the textile pile debridement material demonstrates a more superior in vitro biofilm removal performance than medical gauze. All of these characterizations suggest that the textile pile debridement material can offer a feasible application for clinical wound debridement.},
}
@article {pmid32560208,
year = {2020},
author = {Singh, P and Pandit, S and Mokkapati, V and Garnæs, J and Mijakovic, I},
title = {A Sustainable Approach for the Green Synthesis of Silver Nanoparticles from Solibacillus isronensis sp. and Their Application in Biofilm Inhibition.},
journal = {Molecules (Basel, Switzerland)},
volume = {25},
number = {12},
pages = {},
doi = {10.3390/molecules25122783},
pmid = {32560208},
issn = {1420-3049},
abstract = {The use of bacteria as nanofactories for the green synthesis of nanoparticles is considered a sustainable approach, owing to the stability, biocompatibility, high yields and facile synthesis of nanoparticles. The green synthesis provides the coating or capping of biomolecules on nanoparticles surface, which confer their biological activity. In this study, we report green synthesis of silver nanoparticles (AgNPs) by an environmental isolate; named as AgNPs1, which showed 100% 16S rRNA sequence similarity with Solibacillus isronensis. UV/visible analysis (UV/Vis), transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the synthesized nanoparticles. The stable nature of nanoparticles was studied by thermogravimetric analysis (TGA) and inductively coupled plasma mass spectrometry (ICP-MS). Further, these nanoparticles were tested for biofilm inhibition against Escherichia coli and Pseudomonas aeruginosa. The AgNPs showed minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 3.12 µg/mL and 6.25 µg/mL for E. coli, and 1.56 µg/mL and 3.12 µg/mL for P. aeruginosa, respectively.},
}
@article {pmid32559664,
year = {2020},
author = {Li, K and Qian, J and Wang, P and Wang, C and Lu, B and Jin, W and He, X and Tang, S and Zhang, C and Gao, P},
title = {Responses of freshwater biofilm formation processes (from colonization to maturity) to anatase and rutile TiO2 nanoparticles: Effects of nanoparticles aging and transformation.},
journal = {Water research},
volume = {182},
number = {},
pages = {115953},
doi = {10.1016/j.watres.2020.115953},
pmid = {32559664},
issn = {1879-2448},
abstract = {Most of the current studies on the toxicology of pristine nanoparticles (NPs) are environmentally irrelevant, because their ''aging'' process accompanied by the physicochemical transformation is inevitable in the environment. Considering aging phenomenon will gain a better understanding of the toxicity and fate of NPs in the environment. Here, we focused on the physicochemical transformation of anatase-NPs (TiO2-A) and rutile-NPs (TiO2-R) after 90 days of aging and investigated the responses of freshwater biofilm formation to the stress changes of naturally aged TiO2-NPs (aTiO2-NPs). We found that after aging, the TiO2-NPs underwent sophisticated physicochemical transformations in the original morphology and microstructure owing to organic and crystal salts inclusions, such as energy band changes and the formation of Ti3+ on the NPs surfaces. These comprehensive transformations increased the stability of NPs in the exposed suspension. However, the physicochemical transformations were crystal-forms-dependent, and aging did not change the crystal structure and crystallinity. Interestingly, compared to pristine NPs, aTiO2-NPs showed much lower cytotoxicity and had the weaker ability to promote or inhibit the biofilm formation (p < 0.05) owing to the passivation of photoactivity caused by the comprehensive effect of the inclusions, especially for aTiO2-A. Regardless of aging or not of crystal forms, responses of biofilm formation were exposure-concentration-dependent, namely low concentration promotion (0.1 mg/L) and high concentration inhibition (10 mg/L), e.g., role transition of the pioneers (algae or bacteria) in initial colonization, extracellular polymeric substances (EPS) secretion and compositions of development stages with polysaccharide (PS)-rich and protein (PRO)-rich stages, and biomass and cell activity at different depths of mature biofilms. The reactive oxygen species (ROS) induced by TiO2-NPs showed typical hormesis. The changing trends of the autoinducers (c-di-GMP and quorum sensing signals including AHL and AI-2) were highly consistent with the growth stages of biofilms and were stimulated or suppressed by TiO2-NPs. The NPs crystal-dependently changed the microorganism community structures, while the UPGMA clustering of bacteria was based on the growth stages of the biofilms. The toxic mechanisms revealed that photoactivity and nanoscale retention of particles are the main reasons for the differences in the ecological stress capacity of four kinds of TiO2-NPs. Aging reduced characteristic differences of two pristine NPs and even reversed their relative stresses levels (p > 0.05). However, the toxicity of high-concentration aTiO2-NPs (10 mg/L) remained serious in a water environment. This study provides a better understanding for the water environmental risks evaluation and policy control of nanoparticles, that is, the effect of time aging has to be considered.},
}
@article {pmid32559542,
year = {2020},
author = {Schwarz, A and Suárez, JI and Aybar, M and Nancucheo, I and Martínez, P and Rittmann, BE},
title = {A membrane-biofilm system for sulfate conversion to elemental sulfur in mining-influenced waters.},
journal = {The Science of the total environment},
volume = {740},
number = {},
pages = {140088},
doi = {10.1016/j.scitotenv.2020.140088},
pmid = {32559542},
issn = {1879-1026},
abstract = {A system of two membrane biofilm reactors (MBfRs) was tested for the conversion of sulfate (1.5 g/L) in mining-process water into elemental sulfur (S0) particles. Initially, a H2-based MBfR reduced sulfate to sulfide, and an O2-based MBfR then oxidized sulfide to S0. Later, the two MBfRs were coupled by a recirculation flow. Surface loading, reactor-coupling configuration, and substrate-gas pressure exerted important controls over performance of each MBfR and the coupled system. Continuously recirculating the liquid between the H2-based MBfR and the O2-based MBfR, compared to series operation, avoided the buildup of sulfide and gave overall greater sulfate removal (99% vs 62%) and production of S0 (61% vs 54%). The trade-off was that recirculation coupling demanded greater delivery of H2 and O2 (in air) due to the establishment of a sulfur cycle catalyzed by Sulfurospirillum spp., which had an average abundance of 46% in the H2-based MBfR fibers and 62% in the O2-based MBfR fibers at the end of the experiments. Sulfate-reducing bacteria (Desulfovibrio and Desulfomicrobium) and sulfur-oxidizing bacteria (Thiofaba, Thiomonas, Acidithiobacillus and Sulfuricurvum) averaged only 22% and 11% in the H2-based MBfR and O2-based MBfR fibers, respectively. Evidence suggests that the undesired Sulfurospirillum species, which reduce S0 to sulfide, can be suppressed by increasing sulfate-surface loading and H2 pressure.},
}
@article {pmid32558324,
year = {2020},
author = {Llama-Palacios, A and Potupa, O and Sánchez, MC and Figuero, E and Herrera, D and Sanz, M},
title = {Proteomic analysis of Fusobacterium nucleatum growth in biofilm versus planktonic state.},
journal = {Molecular oral microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/omi.12303},
pmid = {32558324},
issn = {2041-1014},
abstract = {Fusobacterium nucleatum is isolated from both supra- and sub-gingival dental biofilms in humans and has been implicated in the aetiology of periodontitis. Also, this bacterium plays an important role in serious infections in other parts of the body. The aim of this investigation was to study the protein differential expression of F. nucleatum when growing on biofilm, compared to planktonic state, using proteomic analysis by the 2D-DIGE™ system. Sixty-eight proteins were differentially expressed during biofilm growth (1.5-fold, p<0.05), being 20 down-expressed and 31 over-expressed. The repressed proteins belonged to metabolism, biosynthesis, and were outer membrane proteins (OMPs); and over-expressed were proteins involved in metabolism, transcription, translation, transport, and proteins with unknown function. Also, of the seven enzymes that regulate the synthesis of butyrate, six of them were differentially expressed (over- and down-) when the bacteria were forming biofilms. The enzymatic activities of two of the enzymes in the butyrate pathway were analyzed when the bacteria were growing in biofilms or in planktonic growth. All these results confirmed that this metabolic pathway is important in the formation of the biofilm of F. nucleatum and in its pathogenicity, both in the oral cavity and in other locations of the body.},
}
@article {pmid32557120,
year = {2020},
author = {Huang, X and Zheng, M and Yi, Y and Patel, A and Song, Z and Li, Y},
title = {Inhibition of berberine hydrochloride on Candida albicans biofilm formation.},
journal = {Biotechnology letters},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10529-020-02938-6},
pmid = {32557120},
issn = {1573-6776},
support = {17TD0013//Education Department of Sichuan Province/ ; JSZX2018006//Chengdu University of Traditional Chinese Medicine (CN)/ ; },
abstract = {OBJECTIVE: This study aimed to investigate the inhibitory effect of berberine hydrochloride (BH) on Candida albicans (C.albicans) ATCC10231 biofilm formation.<br><br>RESULTS: This paper found a positive correlation between the concentration of BH and its inhibitory effect on the cellular activity of early biofilms because we found that 128 and 32 μg/mL BH significantly inhibited biofilm formation (P < 0.05). BH significantly inhibited the cellular activity in early biofilms, destroyed the microscopic morphology of C.albicans and reduced the thickness of the biofilm. Both 128 and 32 μg/mL concentration solutions of BH significantly inhibited biofilm formation (P < 0.05). We found that the inhibitory effect of BH solution was positively correlated with its concentration and 128 μg/mL BH was better than 4 μg/mL fluconazole. Additionally, the results of RT-PCR indicated that 128 and 32 μg/mL BH inhibited the expression of EFG1, HWP1, ECE1, and ALS1 (P < 0.05).<br><br>CONCLUSION: The efficacy of BH in inhibiting the formation of C.albicans biofilm by killing the cells in the biofilm and destroying its structure; and the mechanism may be to down-regulate the expression of EFG1, HWP1, ECE1, and ALS1 in hyphae formation, thereby, retarding the morphological transformation of C. albicans.},
}
@article {pmid32556007,
year = {2020},
author = {Miranda, SLF and Damaceno, JT and Faveri, M and Figueiredo, LC and Soares, GMS and Feres, M and Bueno-Silva, B},
title = {In Vitro Antimicrobial Effect of Cetylpyridinium Chloride on Complex Multispecies Subgingival Biofilm.},
journal = {Brazilian dental journal},
volume = {31},
number = {2},
pages = {103-108},
doi = {10.1590/0103-6440202002630},
pmid = {32556007},
issn = {1806-4760},
mesh = {Anti-Bacterial Agents ; *Anti-Infective Agents ; *Anti-Infective Agents, Local ; Biofilms ; Cetylpyridinium ; Chlorhexidine ; },
abstract = {Periodontopathogenic subgingival biofilm is the main etiological agent of periodontitis. Thus, a search for antimicrobials as adjuvant for periodontal treatment in the literature is intense. Cetylpyridinium chloride (CPC) is a well-known antimicrobial agent commonly used in mouthrinses. However, CPC effects on a complex biofilm model were not found over the literature. Therefore, the aim of this manuscript is to evaluate 0.075% CPC antimicrobial properties in a multispecies subgingival biofilm model in vitro. The subgingival biofilm composed by 31 species related to periodontitis was formed for 7 days, using the calgary device. The treatments with CPC and chlorhexidine (CHX) 0.12% (as positive control) were performed 2x/day, for 1 min, from day 3 until the end of experimental period, totaling 8 treatments. After 7 days of biofilm formation, biofilm metabolic activity was evaluated by a colorimetric reaction and biofilms microbial composition by DNA-DNA hybridization. Statistical analysis was performed using ANOVA with data transformed via BOX-COX followed by Dunnett post-hoc. Both CPC and CHX reduced biofilm metabolic activity in 60% and presented antimicrobial activity against 13 different species. Specifically, only CHX reduced levels of F.n. vicentii and P. gingivalis while only CPC reduced A. odontolyticus and A. israelli. CPC was as effective as CHX as antimicrobial through in vitro complex multispecies subgingival biofilm. However, future studies using in vivo models of experimental periodontal disease should be performed to prove such effect.},
}
@article {pmid32554257,
year = {2020},
author = {Subbiahdoss, G and Reimhult, E},
title = {Biofilm formation at oil-water interfaces is not a simple function of bacterial hydrophobicity.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {194},
number = {},
pages = {111163},
doi = {10.1016/j.colsurfb.2020.111163},
pmid = {32554257},
issn = {1873-4367},
abstract = {Bacterial adsorption to interfaces is the initial step in biofilm formation. The mechanism of biofilm formation at liquid-liquid interfaces differs from the process of biofilm formation on solid-liquid interfaces. Until now, the former is not well understood. We study the bacterial adsorption and biofilm formation of three different bacteria, P. aeruginosa, S. aureus, and S. epidermidis at the n-decane-water interface, with focus on the relationship between bacteria wettability, excretion of biosurfactants, and biofilm formation. The adhesion capacity of these bacteria to hydrocarbons was characterized using the bacterial adherence to hydrocarbons test. We monitored the interfacial rheology of bacterial adsorption and biofilm formation at the interface over time using a drop shape analyzer and imaged the formed biofilms by using fluorescence and scanning electron microscopy. P. aeruginosa showed high adhesion capacity to hydrocarbons, while the adhesion capacity of both staphylococci was negligible. P. aeruginosa also showed rapid adsorption to the n-decane-water interface as measured by the rapid decrease in interfacial tension for the pure bacteria suspension. However, S. epidermidis, with a negligible hydrophobicity value, showed the most substantial reduction in interfacial tension and the formation of the most elastic biofilms at the oil-water interface. S. epidermidis accomplishes this by the secretion of biosurfactants. S. aureus did not form biofilms at the n-decane-water interface, in contrast to P. aeruginosa and S. epidermidis. We conclude that bacterial adsorption and biofilm formation at oil-water interfaces, in general, are not simple functions of cell hydrophobicity. Biosurfactant modification and metabolism of the interface also play essential roles.},
}
@article {pmid32554017,
year = {2020},
author = {Zhou, Y and Guo, B and Li, R and Zhang, L and Xia, S and Liu, Y},
title = {Treatment of grey water (GW) with high linear alkylbenzene sulfonates (LAS) content and carbon/nitrogen (C/N) ratio in an oxygen-based membrane biofilm reactor (O2-MBfR).},
journal = {Chemosphere},
volume = {258},
number = {},
pages = {127363},
doi = {10.1016/j.chemosphere.2020.127363},
pmid = {32554017},
issn = {1879-1298},
abstract = {Grey water (GW) containing high levels of linear alkylbenzene sulfonates (LAS) can be a threat to the human health and organisms in the environment if not treated properly. Although aerobic treatment may achieve high GW treatment efficacy, conventional aeration can lead to serious foaming. Here, we firstly and systematically evaluated an oxygen-based membrane biofilm reactor (O2-MBfR) for its capacity to simultaneous remove organics and nitrogen from greywater with high LAS levels and carbon/nitrogen (C/N) ratios. After a five-day startup period, multifarious microorganisms formed multifunctional biofilms and the MBfR achieved high removal rates of chemical oxygen demand (COD), LAS, and total nitrogen (TN) of 88.4%, 95.6%, and 80%, respectively, with a hydraulic retention time of 7.86 h. Higher organics loading (5.53 g TCOD/m2-day) caused cell lysis and damaged the O2-MBfR system, leading to a discernible and continuous decline of the reactor performance. The O2-MBfR design completely eliminated foaming formation. LAS -biodegrading-rich genus containing Clostridium, Parvibaculum, Dechloromonas, Desulfovibrio, Mycobacterium, Pseudomonas, and Zoogloea enable the nearly complete removal of LAS even under high C/N conditions. Results demonstrated that the O2-MBfR technology is feasible for treating GW containing high LAS and C/N ratio, while remaining free of foaming formation, and at a low cost due to high O2 utilization rates.},
}
@article {pmid32552790,
year = {2020},
author = {Miao, W and Sheng, L and Yang, T and Wu, G and Zhang, M and Sun, J and Ainiwaer, A},
title = {The impact of flavonoids-rich Ziziphus jujuba Mill. Extract on Staphylococcus aureus biofilm formation.},
journal = {BMC complementary medicine and therapies},
volume = {20},
number = {1},
pages = {187},
pmid = {32552790},
issn = {2662-7671},
support = {Q2015-01-06//the Xinjiang traditional Chinese medicine new drug research and development projects/ ; 81660695//the National Natural Science Foundation of China/ ; 2-14-01//Xinjiang Tianshan talent projects/ ; qn2015jq005//Training project for outstanding young people in science and technology in the Xinjiang/ ; },
abstract = {BACKGROUND: To evaluate the in vitro antibacterial effect of flavonoids-rich Ziziphus jujuba Mill. extract (FZM) against the formation of bacterial biofilms (BBFs) in Staphylococcus aureus.<br><br>RESULTS: FZM can effectively inhibit the formation of S. aureus biofilms in vitro. Morphological observation showed a decrease in both biofilm adhesion and thickness. Results of confocal laser scanning microscopy used to detect the thickness of the BBFs showed that FZM treatment reduced the thickness of the BBFs. Furthermore, after the Image-Pro Plus v.6.0 analysis of the fluorescence intensity, FZM treatment reduced the thickness of the BBFs as well as the proportion of green fluorescence. Scanning electron microscopy showed that FZM can disrupt the channels available for substance exchange in the biofilm, thus exposing the bacterial cells and damaging its three-dimensional structures.<br><br>CONCLUSION: FZM can inhibit biofilm formation, improve the bacterial pH environment, and eliminate the hydrophobic effect of reactive oxygen species and flavonoids.},
}
@article {pmid32552165,
year = {2020},
author = {Grønseth, T and Vestby, LK and Nesse, LL and von Unge, M and Silvola, JT},
title = {Bioactive glass S53P4 eradicates Staphylococcus aureus in biofilm/planktonic states in vitro.},
journal = {Upsala journal of medical sciences},
volume = {},
number = {},
pages = {1-9},
doi = {10.1080/03009734.2020.1765908},
pmid = {32552165},
issn = {2000-1967},
abstract = {Background: Increasing antimicrobial resistance to antibiotics is a substantial health threat. Bioactive glass S53P4 (BAG) has an antimicrobial effect that can reduce the use of antibiotics. The aim of this study was to evaluate the antimicrobial efficacy of BAG in vitro on staphylococci in biofilm and in planktonic form. Secondary aims were to investigate whether supernatant fluid primed from BAG retains the antibacterial capacity and if ciprofloxacin enhances the effect.Methods: BAG-S53P4 granules, <45 µm, primed in tryptic soy broth (TSB) were investigated with granules present in TSB (100 mg/mL) and after removal of granules (100, 200, and 400 mg/mL). The efficacy of BAG to eradicate Staphylococcus aureus biofilm in vitro was tested using 10 different clinical strains and 1 reference strain in three test systems: the biofilm-oriented antiseptic test based on metabolic activity, the biofilm bactericidal test based on culturing surviving bacteria, and confocal laser scanning microscopy (CLSM) combined with LIVE/DEAD staining.Results: Exposure to 48 h primed BAG granules (100 mg/mL) produced bactericidal effects in 11/11 strains (p = 0.001), and CLSM showed reduction of viable bacteria in biofilm (p = 0.001). Supernatant primed 14 days, 400 mg/mL, reduced metabolic activity (p < 0.001), showed bactericidal effects for 11/11 strains (p = 0.001), and CLSM showed fewer viable bacteria (p = 0.001). The supernatant primed for 48 h, or in concentrations lower than 400 mg/mL at 14 days, did not completely eradicate biofilm.Conclusion: Direct exposure to BAG granules, or primed supernatant fluid, effectively eradicated S. aureus in biofilm. The anti-biofilm effect is time- and concentration-dependent. When BAG had reached its full antimicrobial effect, ciprofloxacin had no additional effect.},
}
@article {pmid32550510,
year = {2020},
author = {Arata, Y and Oshima, T and Ikeda, Y and Kimura, H and Sako, Y},
title = {OP50, a bacterial strain conventionally used as food for laboratory maintenance of C. elegans, is a biofilm formation defective mutant.},
journal = {microPublication. Biology},
volume = {2020},
number = {},
pages = {},
pmid = {32550510},
issn = {2578-9430},
}
@article {pmid32549591,
year = {2020},
author = {Nagar, N and Aswathanarayan, JB and Vittal, RR},
title = {Anti-quorum sensing and biofilm inhibitory activity of Apium graveolens L. oleoresin.},
journal = {Journal of food science and technology},
volume = {57},
number = {7},
pages = {2414-2422},
pmid = {32549591},
issn = {0022-1155},
abstract = {Apium graveolens L. (Apiaceae) is a dietary herb used as a spice, condiment and medicine. A. graveolens (Celery) has been studied for its antimicrobial property and for its application as flavours in food industry. The present study investigated the Apium graveolens oleoresin as an anti-quorum sensing and antibiofilm agent. The quorum sensing and biofilm inhibition study was carried out using biosensor strains Chromobacterium violaceum CV12472 and Pseudomonas aeruginosa PAO1. The MIC of celery oleoresin against C. violaceum CV12472 and P. aeruginosa PAO1 was 10 and 25% v/v, respectively. Inhibition of violacein and biofilm formation was tested at concentrations of oleoresins ranging from 1.56 and 50% v/v. The oleoresins showed a concentration dependent QS inhibitory activity and at sub-MIC of 6.25 and 12.5% v/v, the oleoresins significantly inhibited violacein production and biofilm formation (p < 0.05). Similarly, the celery oleoresin had significant QS modulatory effect on swimming, swarming and twitching motility in P. aeruginosa PAO1 at 12.5% v/v (p < 0.05). The major phytoconstituents present in celery oleoresin as analysed by GC-MS were eicosadiene, benzenemethanol and methyl ester which have not been previously reported. The findings suggest that celery has QS and biofilm inhibitory potential against gram negative pathogens and can find application as food intervention techniques.},
}
@article {pmid32548895,
year = {2020},
author = {Cai, Y and Wang, C and Chen, Z and Xu, Z and Li, H and Li, W and Sun, Y},
title = {Transporters HP0939, HP0497, and HP0471 participate in intrinsic multidrug resistance and biofilm formation in Helicobacter pylori by enhancing drug efflux.},
journal = {Helicobacter},
volume = {25},
number = {4},
pages = {e12715},
doi = {10.1111/hel.12715},
pmid = {32548895},
issn = {1523-5378},
support = {81471991//National Natural Science Foundation of China/ ; 81671978//National Natural Science Foundation of China/ ; 81772143//National Natural Science Foundation of China/ ; 81670486//National Natural Science Foundation of China/ ; 81374101//National Natural Science Foundation of China/ ; },
abstract = {BACKGROUND: The multidrug resistance of Helicobacter pylori is becoming an increasingly serious issue. It is therefore necessary to study the mechanism of multidrug resistance of H pylori. We have previously identified that the HP0939, HP0497, and HP0471 transporters affect the efflux of drugs from H pylori. As efflux pumps participate in bacterial multidrug resistance and biofilm formation, we hypothesized that these transporters could be involved in the multidrug resistance and biofilm formation of H pylori.<br><br>MATERIALS AND METHODS: We therefore constructed three knockout strains, Δhp0939, Δhp0497, and Δhp0471, and three high-expression strains, Hp0939he , Hp0497he , and Hp0471he , using the wild-type (WT) 26 695 strain of H pylori as the template. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of wild strains, knockout strains, and high-expression strains to amoxicillin, metronidazole, and other antibiotics were measured. The efflux capacity of high-expression strains and wild strains was compared by Hoechst 33 342 accumulation assay.<br><br>RESULTS: Determination of the MIC and MBC of the antibiotics revealed that the knockout strains were more sensitive to antibiotics, while the high-expression strains were less sensitive to antibiotics, compared to the WT. The ability of the high-expression strains to efflux drugs was significantly higher than that of the WT. We also induced H pylori to form biofilms, and observed that the knockout strains could barely form biofilms and were more sensitive to several antibiotics, compared to the WT. The mRNA expression of hp0939, hp0497, and hp0471 in the clinically sensitive and multidrug-resistant strains was determined, and it was found that these genes were highly expressed in the multidrug-resistant strains that were isolated from the clinics.<br><br>CONCLUSIONS: In this study, we found three transporters involved in intrinsic multidrug resistance of H pylori.},
}
@article {pmid32548178,
year = {2020},
author = {Chen, G and Liang, H},
title = {A novel c-di-GMP signal system regulates biofilm formation in Pseudomonas aeruginosa.},
journal = {Microbial cell (Graz, Austria)},
volume = {7},
number = {6},
pages = {160-161},
doi = {10.15698/mic2020.06.720},
pmid = {32548178},
issn = {2311-2638},
abstract = {The bacterial second messenger cyclic-di-GMP (c-di-GMP) controls biofilm formation and other phenotypes relevant to pathogenesis. The human pathogen Pseudomonas aeruginosa encodes 17 diguanylate cyclase (DGCs) proteins which are required for c-di-GMP synthesis. Therefore, the c-di-GMP regulatory system in P. aeruginosa is highly sophisticated. SiaD, one of the DGC enzymes, is co-transcribed with SiaA/B/C and has been shown to be essential for bacterial aggregate formation in response to environmental stress. However, the detailed function of this operon remains unknown. In our recent paper (Chen et al., doi: 10.15252/embj.2019103412), we have demonstrated that the siaABCD operon encodes a signaling network that regulates biofilm and aggregate formation by modulating the enzymatic activity of SiaD. Among this signaling system, SiaC interaction with SiaD promotes the diguanylate cyclase activity of SiaD and subsequently facilities the intracellular c-di-GMP synthesis; SiaB is a unique protein kinase that phosphorylates SiaC, whereas SiaA phosphatase can dephosphorylate SiaC. The phosphorylation state of SiaC is critical for its interaction with SiaD, which will switch on or off the DGC activity of SiaD. This report unveils a novel signaling system that controls biofilm formation, which may provide a potential target for developing antimicrobial drugs.},
}
@article {pmid32548095,
year = {2020},
author = {Hamida, RS and Ali, MA and Goda, DA and Khalil, MI and Al-Zaban, MI},
title = {Novel Biogenic Silver Nanoparticle-Induced Reactive Oxygen Species Inhibit the Biofilm Formation and Virulence Activities of Methicillin-Resistant Staphylococcus aureus (MRSA) Strain.},
journal = {Frontiers in bioengineering and biotechnology},
volume = {8},
number = {},
pages = {433},
pmid = {32548095},
issn = {2296-4185},
abstract = {Emerging antibiotic-resistant bacteria result in increased mortality and have negative economic impacts. It is necessary to discover new strategies to create alternative antibacterial agents that suppress the bacterial resistance mechanism and limit the spread of serious infectious bacterial diseases. Silver nanoparticles may represent a new medicinal agents as alternative antibiotics affect different bacterial mechanisms such as virulence and resistance. In addition to that of silver nitrate (AgNO3) and ampicillin, for the first time, the inhibitory effect of silver nanoparticles synthesized using Desertifilum sp. (D-SNPs) was evaluated against five pathogenic bacteria using the agar well diffusion method. Also, the influence of D-SNPs and AgNO3 on bacterial antioxidant and metabolic activities was studied. The antibacterial activity of D-SNPs and AgNO3 against methicillin-resistant Staphylococcus aureus (MRSA) strains was studied at the morphological and molecular level. D-SNPs and AgNO3 have the ability to inhibit the growth of the five bacterial strains and resulted in an imbalance in the CAT, GSH, GPx and ATPase levels. MRSA treated with D-SNPs and AgNO3 showed different morphological changes such as apoptotic bodies formation and cell wall damage. Moreover, both caused genotoxicity and denaturation of MRSA cellular proteins. Additionally, TEM micrographs showed the distribution of SNPs synthesized by MRSA. This result shows the ability of MRSA to reduce silver nitrate into silver nanoparticles. These data indicate that D-SNPs may be a significant alternative antibacterial agent against different bacteria, especially MDR bacteria, by targeting the virulence mechanism and biofilm formation, leading to bacterial death.},
}
@article {pmid32547965,
year = {2020},
author = {Colquhoun, JM and Rather, PN},
title = {Insights Into Mechanisms of Biofilm Formation in Acinetobacter baumannii and Implications for Uropathogenesis.},
journal = {Frontiers in cellular and infection microbiology},
volume = {10},
number = {},
pages = {253},
pmid = {32547965},
issn = {2235-2988},
abstract = {Multidrug resistant Acinetobacter baumannii is a serious healthcare threat. In fact, the Center for Disease Control recently reported that carbapenem-resistant A. baumannii is responsible for more than 8,500 infections, 700 deaths, and $281 million in healthcare costs annually in the United States with few, if any, treatment options available, leading to its designation as a pathogen of urgent concern and a priority for novel antimicrobial development. It is hypothesized that biofilms are, at least in part, responsible for the high prevalence of A. baumannii nosocomial and recurrent infections because they frequently contaminate hospital surfaces and patient indwelling devices; therefore, there has been a recent push for mechanistic understanding of biofilm formation, maturation and dispersal. However, most research has focused on A. baumannii pneumonia and bloodstream infections, despite a recent retrospective study showing that 17.1% of A. baumannii isolates compiled from clinical studies over the last two decades were obtained from urinary samples. This highlights that A. baumannii is an underappreciated uropathogen. The following minireview will examine our current understanding of A. baumannii biofilm formation and how this influences urinary tract colonization and pathogenesis.},
}
@article {pmid32547124,
year = {2020},
author = {Khoshnood, S and Savari, M and Abbasi Montazeri, E and Farajzadeh Sheikh, A},
title = {Survey on Genetic Diversity, Biofilm Formation, and Detection of Colistin Resistance Genes in Clinical Isolates of Acinetobacter baumannii.},
journal = {Infection and drug resistance},
volume = {13},
number = {},
pages = {1547-1558},
pmid = {32547124},
issn = {1178-6973},
abstract = {Introduction: Acinetobacter baumannii is an opportunistic pathogen responsible for nosocomial infections. The emergence of colistin-resistant A. baumannii is a significant threat to public health. The aim of this study was to investigate the molecular characterization and genotyping of clinical A. baumannii isolates in Southwestern Iran.<br><br>Methods: A total of 70 A. baumannii isolates were collected from patients admitted to Imam Khomeini Hospital in Ahvaz, Southwestern Iran. Minimum inhibitory concentration test was conducted by using Vitek 2 system. The presence of biofilm-forming genes and colistin resistance-related genes were evaluated by PCR. The isolates were also examined for their biofilm formation ability and the expression of pmrA and pmrB genes. Finally, multilocus sequence typing (MLST) and PCR-based sequence group were used to determine the genetic relationships of the isolates.<br><br>Results: Overall, 61 (87.1%) and 9 (12.8%) isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR), respectively. Colistin and tigecycline with 2 (2.8%) and 32 (45.7%) resistance rates had the highest effect. Among all the isolates, 55 (78.5%), 7 (10%), and 3 (4.3%) were strong, moderate, and weak biofilm producers, respectively. The frequency rates of biofilm-related genes were 64 (91.4%), 70 (100%), 56 (80%), and 22 (31.42%) for bap, ompA, csuE, and blaPER1 , respectively. Overexpression of pmrA and pmrB genes was observed in two colistin-resistance isolates, but the expression of these genes did not change in colistin-sensitive isolates. Additionally, 37 (52.8%) and 8 (11.4%) isolates belonged to groups 1 (ICII) and 2 (IC I), respectively. MLST analysis revealed a total of nine different sequence types that six isolates belonged to clonal complex 92 (corresponding to ST801, ST118, ST138, ST 421, and ST735). Other isolates were belonging to ST133 and ST216, and two colistin-resistant (Ab4 and Ab41) isolates were belonging to ST387 and ST1812.<br><br>Conclusion: The present study revealed the presence of MDR and XDR A. baumannii isolates harboring biofilm genes and emergence of colistin-resistant isolates in Southwestern Iran. These isolates had high diversity, which was affirmed by typing techniques. The control measures and regular surveillance are urgently needed to preclude the spread of these isolates.},
}
@article {pmid32546074,
year = {2020},
author = {Thakur, S and Ray, S and Jhunjhunwala, S and Nandi, D},
title = {Insights into coumarin-mediated inhibition of biofilm formation in Salmonella Typhimurium.},
journal = {Biofouling},
volume = {36},
number = {4},
pages = {479-491},
doi = {10.1080/08927014.2020.1773447},
pmid = {32546074},
issn = {1029-2454},
abstract = {Coumarins have been shown to possess antimicrobial, anti-quorum sensing and anti-biofilm properties against a wide range of pathogenic bacteria. This study aimed to shed light on the effects of non-substituted coumarin on biofilm formation by the foodborne pathogen Salmonella Typhimurium. Additionally, its efficacy was tested in combination with another potent anti-biofilm agent, resveratrol. Coumarin inhibited biofilm formation for prolonged periods in millimolar concentrations with marginal effects on planktonic growth. It attenuated curli and cellulose production, likely by downregulating the transcript levels of major biofilm formation genes csgD, csgA and adrA. Coumarin further restricted motility in a dose-dependent manner. In addition, coumarin with resveratrol exhibited improved anti-biofilm properties compared with the individual compounds alone. Thus, coumarin alone or with resveratrol can be employed for inhibiting biofilms in food storage and processing units.},
}
@article {pmid32545793,
year = {2020},
author = {Doub, JB and Heil, EL and Ntem-Mensah, A and Neeley, R and Ching, PR},
title = {Rifabutin Use in Staphylococcus Biofilm Infections: A Case Series.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {9},
number = {6},
pages = {},
doi = {10.3390/antibiotics9060326},
pmid = {32545793},
issn = {2079-6382},
abstract = {This is a case series of 10 patients who had staphylococcal biofilm infections that were treated with adjuvant rifabutin therapy instead of rifampin therapy. In these cases, rifampin was contraindicated secondary to drug-drug interactions with the patients' chronic medications. Rifabutin therapy was well tolerated with no side effects. As well, no patients had recurrence of their staphylococcal infections. This case series shows that rifabutin can be a beneficial adjuvant therapy in Staphylococcus biofilm infections when drug-drug interactions limit the use of rifampin.},
}
@article {pmid32544646,
year = {2020},
author = {Aldakheel, FM and Alduraywish, SA and Jhugroo, P and Jhugroo, C and Divakar, DD},
title = {Quantification of pathogenic bacteria in the subgingival oral biofilm samples collected from cigarette-smokers, individuals using electronic nicotine delivery systems and non-smokers with and without periodontitis.},
journal = {Archives of oral biology},
volume = {117},
number = {},
pages = {104793},
doi = {10.1016/j.archoralbio.2020.104793},
pmid = {32544646},
issn = {1879-1506},
abstract = {OBJECTIVE: The aim of the present study was to quantify pathogenic bacteria isolated from the subgingival oral-biofilm samples collected from cigarette-smokers and ENDS-users with periodontitis, when compared to non-smokers with and without periodontitis.<br><br>METHODS: Demographic data was collected using a questionnaire. Periodontal parameters (plaque [PI] and gingival [GI] indices, clinical attachment loss [CAL], probing depth [PD] and marginal bone loss [MBL]) were measured. Subgingival oral bio-film samples were collected and assessed for periodontopathogenic bacteria (Aggregatibacter actinomycetemcomitans [A. actinomycetemcomitans], Prevotella intermedia [P. intermedia], Porphyromonas gingivalis [P. gingivalis], Tannerella forsythia [T. forsythia] and Treponema denticola [T. denticola]). Group-comparisons were performed; and P < 0.01 were considered statistically significant.<br><br>RESULTS: All cigarette-smokers, ENDS-users and non-smokers with periodontitis had Grade-B periodontitis. The CFU/mL of A. actinomycetemcomitans (P < 0.001) and P. gingivalis (P < 0.001) were significantly higher among cigarette-smokers (P < 0.01) and ENDS-users (P < 0.01) than non-smokers with periodontitis. The CFU/mL of T. denticola were significantly higher among cigarette-smokers (P < 0.001), ENDS-users (P < 0.001) and non-smokers with periodontitis (P < 0.001) compared with non-smokers without periodontitis. There was no statistically significant difference in the CFU/mL of P. intermedia and T. denticola among cigarette-smokers, ENDS-users and non-smokers with periodontitis.<br><br>CONCLUSION: Counts of periodontopathogenic bacteria in the subgingival oral-biofilm are comparable among cigarette-smokers and individuals using ENDS.},
}
@article {pmid32543337,
year = {2020},
author = {Grygorcewicz, B and Wojciuk, B and Roszak, M and Łubowska, N and Błażejczak, P and Jursa-Kulesza, J and Rakoczy, R and Masiuk, H and Dołęgowska, B},
title = {Environmental Phage-Based Cocktail and Antibiotic Combination Effects on Acinetobacter baumannii Biofilm in a Human Urine Model.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2020.0083},
pmid = {32543337},
issn = {1931-8448},
abstract = {The emergence of multidrug-resistant (MDR) bacterial infections poses a catastrophic threat to medicine. The development of phage-based therapy combined with antibiotics might be an advantageous weapon in the arms race between human and MDR bacteria. A cocktail composed of the MDR Acinetobacter baumannii infecting bacteriophages with high lytic activity was used in combination with antibiotics to destroy a bacterial biofilm in human urine. A. baumannii exhibited varying susceptibility to the host range of bacteriophages used in this study, ranging from 56% to 84%. This study demonstrated that bacteriophages could reduce biofilm biomass in a human urine model, and some of the antibiotics commonly used in the treatment of urinary tract infection (UTI) act synergistically with phage cocktails. Additionally, the combined treatment showed a significantly greater reduction of biofilm biomass and clearance of persister cells.},
}
@article {pmid32542998,
year = {2020},
author = {Hartman, AM and Jumde, VR and Elgaher, WAM and Te Poele, EM and Dijkhuizen, L and Hirsch, AKH},
title = {Dynamic Combinatorial Chemistry Affords Sugar-Based Molecules Targeting Bacterial Glucosyltranseferase as Potential Dental Biofilm Inhibitors.},
journal = {ChemMedChem},
volume = {},
number = {},
pages = {},
doi = {10.1002/cmdc.202000222},
pmid = {32542998},
issn = {1860-7187},
abstract = {We applied dynamic combinatorial chemistry (DCC) to find novel ligands of the bacterial virulence factor glucosyltransferase (GTF) 180. GTFs are the major producers of extracellular polysaccharides, which are important factors in the initiation and development of cariogenic dental biofilms. Following a structure-based strategy, we designed a series of 36 glucose- and maltose-based acylhydrazones as substrate mimics. Synthesis of the required mono- and disaccharide-based aldehydes set the stage for DCC experiments. Analysis of the dynamic combinatorial libraries (DCLs) via UPLC-MS revealed major amplification of four compounds in the presence of GTF180. Moreover, we found that derivatives of the glucose-acceptor maltose at the C1-hydroxyl group are acting as glucose-donors and are cleaved by GTF180. The synthesized hits display medium to low binding affinity (KD values of 0.4-10.0 mm) according to surface plasmon resonance (SPR). In addition, they were investigated for the inhibitory activity using the GTF-activity assays. The early stage DCC study reveals that careful design of DCLs opens up easy access to a broad class of novel compounds that can be developed further as potential inhibitors.},
}
@article {pmid32542738,
year = {2020},
author = {Zhang, C and Zhu, F and Jatt, AN and Liu, H and Niu, L and Zhang, L and Liu, Y},
title = {Characterization of co-culture of Aeromonas and Pseudomonas bacterial biofilm and spoilage potential on refrigerated grass carp (Ctenopharyngodon idellus).},
journal = {Letters in applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/lam.13341},
pmid = {32542738},
issn = {1472-765X},
abstract = {Aeromonas and Pseudomonas are important bacterial species involved in spoilage of refrigerated freshwater fish. In this study, ten Aeromonas and seven Pseudomonas bacterial strains were isolated from spoiled grass carp and identified. Twelve out of seventeen bacterial strains showed high potential of biofilm formation and fourteen out of seventeen can produce extracellular protease. In order to explore the spoilage capacity of dual-species, the sterile grass carp fillets were inoculated with mono- and dual-species of A. salmonicida and P. azotoformans strains. The results revealed significantly higher levels of the total viable count and total volatile basic nitrogen in dual-species as compared to mono-species from day 6. The higher contents of histamine, cadaverine and serious degradation in muscles tissue were also observed in dual-species after 10 days of storage. Results of in vitro experiments showed that the co-culture of A. salmonicida and P. azotoformans significantly increased the bacterial maximum growth rate, promoted the biofilm formation, and improved the spoilage capacity of bacterial strains. This study has revealed that the co-culture of Aeromonas and Pseudomonas bacterial strains accelerated spoilage process of grass carp and increased biofilm formation. It indicates that the mixed- cultures of spoilage microorganisms pose a huge threat to food industry.},
}
@article {pmid32541123,
year = {2020},
author = {Wang, C and Lei, L and Cai, F and Li, Y},
title = {Nitrogen removal and microbial communities of a completely autotrophic nitrogen removal over nitrite (CANON) sequencing batch biofilm reactor (SBBR) at different inorganic carbon (IC) concentrations.},
journal = {Water science and technology : a journal of the International Association on Water Pollution Research},
volume = {81},
number = {5},
pages = {1071-1079},
doi = {10.2166/wst.2020.203},
pmid = {32541123},
issn = {0273-1223},
mesh = {Autotrophic Processes ; Biofilms ; Bioreactors ; Carbon ; Denitrification ; *Microbiota ; *Nitrites ; Nitrogen ; },
abstract = {In this study, the completely autotrophic nitrogen removal over nitrite (CANON) process was initiated in a sequencing batch biofilm reactor (SBBR). Then the reactor was operated under different IC/N ratios. The total inorganic nitrogen removal efficiency (TINRE) at IC/N ratios of 0.75, 1.0, 1.25, 1.5 and 2.0 were 37.0 ± 11.0%, 58.9 ± 10.2%, 73.9 ± 3.2%, 73.6 ± 1.8% and 72.6 ± 2.0%, respectively. The suitable range of IC/N ratio in this research is 1.25-2.0. The poor nitrogen removal performance at IC/N ratio of 0.75 was due to the lack of growth substrate for AnAOB and low pH simultaneously; at IC/N ratio of 1.0 this was because the substrate concentration was insufficient for fully recovering the AnAOB activities. Microbial analysis indicated that Nitrosomonas, Nitrospira and Candidatus Brocadia were the main ammonium oxidation bacteria (AOB), nitrite oxidation bacteria (NOB) and anammox bacteria (AnAOB), respectively. In addition, at IC ratios of 1.25 or higher, denitrification was promoted with the rise of IC/N ratio, which might be because the change of IC concentrations caused cell lysis of microorganisms and provided organic matter for denitrification.},
}
@article {pmid32541108,
year = {2020},
author = {Skoyles, A and Chaganti, SR and Mundle, SOC and Weisener, CG},
title = {'Nitrification kinetics and microbial community dynamics of attached biofilm in wastewater treatment'.},
journal = {Water science and technology : a journal of the International Association on Water Pollution Research},
volume = {81},
number = {5},
pages = {891-905},
doi = {10.2166/wst.2020.170},
pmid = {32541108},
issn = {0273-1223},
mesh = {Ammonia ; Biofilms ; Bioreactors ; Denitrification ; Kinetics ; *Microbiota ; *Nitrification ; Nitrogen ; RNA, Ribosomal, 16S ; Waste Water ; },
abstract = {A comparative bench-scale and field site analysis of BioCord was conducted to investigate seasonal microbial community dynamics and its impact on nitrogen removal in wastewater. This was assessed using metabolite (NO3-) stable isotope analysis, high-throughput sequencing of the 16S rRNA gene, and RT-qPCR of key genes in biological treatment representing nitrification, anammox, and denitrification. Bench-scale experiments showed an increase in nitrifiers with increasing ammonia loading resulting in an ammonia removal efficiency up to 98 ± 0.14%. Stable isotope analysis showed that 15ɛ and δ18ONO3 could be used in monitoring the efficiency of the enhanced biological nitrification. In the lagoon field trials, an increase in total nitrogen promoted three principle nitrifying genera (Nitrosomonas, Nitrospira, Candidatus Nitrotoga) and enhanced the expression of denitrification genes (nirK, norB, and nosZ). Further, anaerobic ammonia oxidizers were active within BioCord biofilm. Even at lower temperatures (2-6°C) the nitrifying bacteria remained active on the BioCord.},
}
@article {pmid32540933,
year = {2020},
author = {Parthasarathy, S and Jordan, LD and Schwarting, N and Woods, MA and Abdullahi, Z and Varahan, S and Passos, PMS and Miller, B and Hancock, LE},
title = {Involvement of chromosomally encoded homologs of the RRNPP protein family in Enterococcus faecalis biofilm formation and UTI pathogenesis.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00063-20},
pmid = {32540933},
issn = {1098-5530},
abstract = {Enterococcus faecalis is an opportunistic pathogen capable of causing infections including endocarditis and urinary tract infections (UTI). One of the well characterized quorum sensing pathways in E. faecalis involves coordination of the conjugal transfer of pheromone-responsive plasmids by PrgX, a member of the RRNPP protein family. Members of this protein family in various Firmicutes have also been shown to contribute to numerous cellular processes including sporulation, competence, conjugation, nutrient sensing, biofilm formation and virulence. As PrgX is a plasmid-encoded RRNPP family member, we surveyed the genome of the multi-drug resistant strain V583 for additional RRNPP homologs using computational searches and refined those identified hits for predicted structural similarities to known RRNPP family members. This led us to investigate the contribution of the chromosomally encoded RRNPP homologs to biofilm processes and pathogenesis in a catheter associated urinary tract infection (CAUTI) model. In this study, we identified five such homologs and report that 3 of the 5 homologs, EF0073, EF1599 and EF1316, affect biofilm formation as well as outcomes in the CAUTI model.ImportanceEnterococcus faecalis causes healthcare-associated infections and displays resistance to a variety of broad spectrum antibiotics by acquisition of resistance traits as well as the ability to form biofilms. Even though a growing number of factors related to biofilm formation have been identified, mechanisms that contribute to biofilm formation are still largely unknown. The RRNPP protein family regulate a diverse set of biological reactions in low G-C Gram-positive bacteria (Firmicutes). Here we identify three predicted structural homologs of the RRNPP family, EF0073, EF1599 and EF1316, which affect biofilm formation and CAUTI pathogenesis.},
}
@article {pmid32540665,
year = {2020},
author = {Yuan, S and Yu, Z and Pan, S and Huang, J and Meng, F},
title = {Deciphering the succession dynamics of dominant and rare genera in biofilm development process.},
journal = {The Science of the total environment},
volume = {739},
number = {},
pages = {139961},
doi = {10.1016/j.scitotenv.2020.139961},
pmid = {32540665},
issn = {1879-1026},
abstract = {Deciphering the succession dynamics of dominant and rare taxa is crucial to understand the stability and ecosystem functions of biofilm communities. However, the essential laws of the succession dynamics based on dominant and rare taxa were still unenlightened. Herein, we investigated the succession dynamics of dominant and rare genera in multi-species biofilms developed in flow cells fed with 10 and 40 mg-TOC/L LB broth. The relative abundance of dominant genera (Enterobacteria and Acinetobacter) decreased remarkably (from 94.63% to 73.22%) in 10 mg-TOC/L LB broth, whereas they kept relatively steady (93.75 ± 4.23%) along with the cultivation time in 40 mg-TOC/L LB broth. Fluorescence in situ hybridization showed that rare genera tended to form clusters at both concentrations, while weaker dispersal of dominant genera caused patchier biofilm structures in 10 mg-TOC/L LB broth compared to that in 40 mg-TOC/L LB broth. Null model analyses further demonstrated that the stochastic ecological drift was more pronounced in the community assembly of biofilms in 10 mg-TOC/L LB broth (73.33%) than those in 40 mg-TOC/L LB broth (60.95%), weakening the competitive superiority of dominant taxa in the patchier biofilms. In addition, the co-occurrence network reflected that the positive interactions among rare genera contributed to exclude dominant genera in 10 mg-TOC/L LB broth, whereas negative interactions only occurred between the dominant Enterobacter and Acinetobacter or rare Comamonas in 40 mg-TOC/L LB broth. This study highlighted the distinctive succession dynamics of dominant and rare genera in biofilms at different substrate concentrations, which would advance our understanding of the biofilm communities in biofilm-related process.},
}
@article {pmid32539963,
year = {2020},
author = {Wu, S and Huang, J and Zhang, F and Dai, J and Pang, R and Zhang, J and Zeng, H and Gu, Q and Zhang, S and Zhang, Y and Xue, L and Wang, J and Ding, Y and Wu, Q},
title = {Staphylococcus argenteus isolated from retail foods in China: Incidence, antibiotic resistance, biofilm formation and toxin gene profile.},
journal = {Food microbiology},
volume = {91},
number = {},
pages = {103531},
doi = {10.1016/j.fm.2020.103531},
pmid = {32539963},
issn = {1095-9998},
abstract = {Staphylococcus argenteus is a novel species of coagulase-positive staphylococci which was separated from Staphylococcus aureus in 2014. It can threaten human health like S. aureus but can not identify with conventional biochemical or other phenotypic testing. From 2011 to 2016, 1581 S. aureus strains were isolated from 4300 samples from retail foods covering most provincial capitals in China. According to multilocus sequence typing (MLST) and PCR confirmation, 7.2% of isolates (114/1581) were confirmed as S. argenteus. The pathogen was distributed in 22 of 39 sampled cities and all food types. Interestingly, most S. argenteus positive samples were collected from coastal cities in South China. MLST detected 8 different sequence types (STs), including five new STs. CC2250 was the predominant lineage of S. argenteus, followed by CC1223. To further characterize the isolates, their antibiotic resistance, virulence genes, biofilm formation and biofilm-related genes were examined. The pvl gene was not detected in S. argenteus, and only 1 isolate (0.9%) was positive for the tsst-1 gene. For 18 enterotoxin genes, 16.7% (19/114) of isolates harboured more than three genes, whereas 70.2% (80/114) of isolates had none of the investigated genes. Penicillin and ampicillin were the major antibiotics to which the S. argenteus isolates were resistant, followed by tetracycline, kanamycin and fusidic acid. A total of 94.7% of isolates had the ability to produce biofilms and all isolates harboured icaA, fnbA, and fib genes. Other biofilm-related genes, such as eno, clfB, fnbB, and icaC, were also found in 99.1%, 92.1%, 88.6%, and 74.6% of isolates, respectively. This study is the first systematic investigation of the prevalence of S. argenteus in retail foods in China and shows their ubiquity in food. We also provide comprehensive surveillance of the incidence of S. argenteus in retail foods and information to enable more accurate and effective treatment of infections of this new species.},
}
@article {pmid32538610,
year = {2020},
author = {Martínez, SR and Ibarra, LE and Ponzio, RA and Forcone, MV and Wendel, AB and Chesta, CA and Spesia, MB and Palacios, RE},
title = {Photodynamic Inactivation of ESKAPE Group Bacterial Pathogens in Planktonic and Biofilm Cultures Using Metallated Porphyrin-Doped Conjugated Polymer Nanoparticles.},
journal = {ACS infectious diseases},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsinfecdis.0c00268},
pmid = {32538610},
issn = {2373-8227},
abstract = {Photodynamic inactivation (PDI) protocols using photoactive metallated porphyrin-doped conjugated polymer nanoparticles (CPNs) and blue light were developed to eliminate multidrug-resistant pathogens. CPNs-PDI protocols using varying particle concentrations and irradiation doses were tested against nine pathogenic bacterial strains including antibiotic-resistant bacteria of the ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens group. The bactericidal effect was achieved in methicillin-resistant Staphylococus aureus (S. aureus) strains using low light doses (9.6-14.4 J/cm2), while Gram-negative bacteria required a higher light dose (28.8 J/cm2). The bacteria-CPN interaction was studied through flow cytometry, taking advantage of the intrinsic CPN fluorescence, demonstrating that CPNs efficiently bind to the bacterial envelope. Finally, the performance of CPNs-PDI was explored in biofilms; good antibiofilm ability and almost complete eradication were observed for S. aureus and Escherichia coli biofilms, respectively, using confocal microscopy. Overall, we demonstrated that CPNs-PDI is an efficient tool not only to kill superbugs as sessile cells but also to disrupt and eradicate biofilms of highly relevant pathogenic bacterial species.},
}
@article {pmid32528653,
year = {2019},
author = {Septiana, S and Bachtiar, BM and Yuliana, ND and Wijaya, CH},
title = {Cajuputs candy impairs Candida albicans and Streptococcus mutans mixed biofilm formation in vitro.},
journal = {F1000Research},
volume = {8},
number = {},
pages = {1923},
doi = {10.12688/f1000research.20700.2},
pmid = {32528653},
issn = {2046-1402},
abstract = {Background:Cajuputs candy (CC), an Indonesian functional food, utilizes the bioactivity of Melaleuca cajuputi essential oil (MCEO) to maintain oral cavity health. Synergistic interaction between Candida albicans and Streptococcus mutans is a crucial step in the pathogenesis of early childhood caries. Our recent study revealed several alternative MCEOs as the main flavors in CC. The capacity of CC to interfere with the fungus-bacterium relationship remains unknown. This study aimed to evaluate CC efficacy to impair biofilm formation by these dual cariogenic microbes. Methods: The inhibition capacity of CC against mixed-biofilm comprising C. albicans and S. mutans was assessed by quantitative (crystal violet assay, tetrazolium salt [MTT] assay, colony forming unit/mL counting, biofilm-related gene expression) and qualitative analysis (light microscopy and scanning electron microscopy). Result: Both biofilm-biomass and viable cells were significantly reduced in the presence of CC. Scanning electron microscopy imaging confirmed this inhibition capacity, demonstrating morphology alteration of C. albicans, along with reduced microcolonies of S. mutans in the biofilm mass. This finding was related to the transcription level of selected biofilm-associated genes, expressed either by C. albicans or S. mutans. Based on qPCR results, CC could interfere with the transition of C. albicans yeast form to the hyphal form, while it suppressed insoluble glucan production by S. mutans. G2 derived from Mojokerto MCEO showed the greatest inhibition activity on the relationship between these cross-kingdom oral microorganisms (p < 0.05). Conclusion: In general, all CC formulas showed biofilm inhibition capacity. Candy derived from Mojokerto MCEO showed the greatest capacity to maintain the yeast form of C. albicans and to inhibit extracellular polysaccharide production by S. mutans. Therefore, the development of dual-species biofilms can be impaired effectively by the CC tested.},
}
@article {pmid32535996,
year = {2020},
author = {Galego, L and Barahona, S and Romão, CV and Arraiano, CM},
title = {Phosphorylation status of BolA affects its role in transcription and biofilm development.},
journal = {The FEBS journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/febs.15447},
pmid = {32535996},
issn = {1742-4658},
abstract = {BolA has been characterized as an important transcriptional regulator, which is induced in stationary phase of growth, and in response to several stresses. In E. coli its cellular function is associated with cell wall synthesis and division, morphology, permeability, motility and biofilm formation. Phosphorylation has been widely described as one of the most important events involved in the modulation of the activity of many transcription factors. In the present work, we have demonstrated in vivo and by mass spectrometry that BolA is phosphorylated in four highly conserved protein positions: S26, S45, T81 and S95. S95 is located in the C-terminus unstructured region of the protein and the other three sites are in the DNA binding domain. These positions were mutated to non-phosphorylated residues and their effects were investigated on different known BolA functions. Using Northern blot experiments we showed that the regulation of the expression of these Ser/Thr BolA mutants is performed at the post-translational level. Western blot results revealed that the stability/turnover of the mutated BolA proteins is differently affected depending on the dephosphorylated residue. Moreover, we provide evidences that phosphorylation events are crucial in the modulation of BolA activity as a transcription factor and as a regulator of cell morphology and biofilm development. Here we propose that phosphorylation affects BolA downstream functions, and discuss the possible significance of these phospho-residues in the protein structure, stability, dimerization and function as a transcription factor.},
}
@article {pmid32534180,
year = {2020},
author = {Ouyang, J and Feng, W and Lai, X and Chen, Y and Zhang, X and Rong, L and Sun, F and Chen, Y},
title = {Quercetin inhibits Pseudomonas aeruginosa biofilm formation via the vfr-mediated lasIR system.},
journal = {Microbial pathogenesis},
volume = {149},
number = {},
pages = {104291},
doi = {10.1016/j.micpath.2020.104291},
pmid = {32534180},
issn = {1096-1208},
abstract = {Pseudomonas aeruginosa is one of the most common opportunistic pathogens that cause biofilm-associated infections. Biofilm formation is partially regulated by the quorum sensing (QS) system, and quercetin can inhibit QS, biofilm formation and virulence factors. We therefore speculated that quercetin would inhibit the formation of P. aeruginosa biofilm via the QS system. In this study, we successfully constructed lasI, rhlI and lasI/rhlI gene-knockout strains. The knockout of the lasI and lasI/rhlI genes resulted in decreases in adhesion, biofilm formation, swarming motility and the expression of biofilm-associated genes, whereas deletion of the rhlI gene had no obvious influence on these biofilm-related indicators with the exception of the swarming motility. After treatment with quercetin, the lasI- and lasI/rhlI-mutant strains exhibited increased adhesion, biofilm formation, swarming motility and biofilm-associated gene expression compared with the control group. However, quercetin still exerted an inhibitory effect on these physiological factors and the biofilm-associated gene expression in the rhlI-mutant strain. The knockout of QS genes reduced the production of pyocyanin and protease activity, but after the virulence factors of the QS-mutant strains treated with quercetin showed almost no differences compared with those of the control group. In addition, quercetin could significantly inhibit vfr gene expression regardless of the presence of QS genes. The results indicated that quercetin might inhibit the lasIR system through the vfr gene and ultimately the formation of P. aeruginosa biofilms.},
}
@article {pmid32534091,
year = {2020},
author = {Barzkar, N},
title = {Marine microbial alkaline protease: Arecent developments in biofilm n ideal choice for industrial application.},
journal = {International journal of biological macromolecules},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijbiomac.2020.06.072},
pmid = {32534091},
issn = {1879-0003},
abstract = {With the modern world focusing on environmental friendly products, more and more chemical processes are being replaced by enzymatic methods. Alkaline proteases (APases) place more than 50% of the total world enzyme production. Marine microorganisms are capable of producing an extensive spectrum of APases which have important ecological roles and promising industrial applications. Marine microbial APases can meet the required market demand for various industrial processes due to their strong specificity, mild reaction conditions, environmental friendliness and easy inactivation or control in comparison with chemical catalysts. In this review, a bird's-eye view on recent research works in the field of APase production from marine microorganisms as well as their potential industrial applications. The effect of various physical and chemical parameters on marine microbial APase is discussed. Isolation, purification, optimum pH and temperature of marine microbial APases are also reported. We anticipate that this review will provide an outline of potential industrial application of marine microbial APases and open new avenues to help the academicians, researchers and industrialists.},
}
@article {pmid32534064,
year = {2020},
author = {Richter, AM and Possling, A and Malysheva, N and Yousef, KP and Herbst, S and von Kleist, M and Hengge, R},
title = {Local c-di-GMP signaling in the control of synthesis of the E. coli biofilm exopolysaccharide pEtN-cellulose.},
journal = {Journal of molecular biology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jmb.2020.06.006},
pmid = {32534064},
issn = {1089-8638},
abstract = {In many bacteria the biofilm-promoting second messenger c-di-GMP is produced and degraded by multiple diguanylate cyclases (DGC) and phosphodiesterases (PDE), respectively. High target specificity of some of these enzymes has led to theoretical concepts of 'local' c-di-GMP signaling. In Escherichia coli K-12, which has 12 DGCs and 13 PDEs, a single DGC, DgcC, is specifically required for the biosynthesis of the biofilm exopolysaccharide pEtN-cellulose without affecting the cellular c-di-GMP pool, but the mechanistic basis of this target specificity has remained obscure. DGC activity of membrane-associated DgcC, which is demonstrated in vitro in nanodiscs, is shown to be necessary and sufficient to specifically activate cellulose biosynthesis in vivo. DgcC as well as a particular PDE, PdeK (encoded right next to the cellulose operon), directly interact with cellulose synthase subunit BcsB and with each other, thus establishing physical proximity between cellulose synthase and a local source and sink of c-di-GMP. This arrangement provides a localized, yet open source of c-di-GMP right next to cellulose synthase subunit BcsA, which needs allosteric activation by c-di-GMP. Through mathematical modelling and simulation we demonstrate that BcsA binding from the low cytosolic c-di-GMP pool in E. coli is negligible, whereas a single c-di-GMP molecule that is produced and released in direct proximity to cellulose synthase increases the probability of c-di-GMP binding to BcsA several hundred-fold. This local c-di-GMP signaling could provide a blueprint for target-specific second messenger signaling also in other bacteria where multiple second messenger producing and degrading enzymes exist.},
}
@article {pmid32533131,
year = {2020},
author = {Rumbaugh, KP and Sauer, K},
title = {Biofilm dispersion.},
journal = {Nature reviews. Microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41579-020-0385-0},
pmid = {32533131},
issn = {1740-1534},
abstract = {The formation of microbial biofilms enables single planktonic cells to assume a multicellular mode of growth. During dispersion, the final step of the biofilm life cycle, single cells egress from the biofilm to resume a planktonic lifestyle. As the planktonic state is considered to be more vulnerable to antimicrobial agents and immune responses, dispersion is being considered a promising avenue for biofilm control. In this Review, we discuss conditions that lead to dispersion and the mechanisms by which native and environmental cues contribute to dispersion. We also explore recent findings on the role of matrix degradation in the dispersion process, and the distinct phenotype of dispersed cells. Last, we discuss the translational and therapeutic potential of dispersing bacteria during infection.},
}
@article {pmid32532998,
year = {2020},
author = {Thibeaux, R and Soupé-Gilbert, ME and Kainiu, M and Girault, D and Bierque, E and Fernandes, J and Bähre, H and Douyère, A and Eskenazi, N and Vinh, J and Picardeau, M and Goarant, C},
title = {The zoonotic pathogen Leptospira interrogans mitigates environmental stress through cyclic-di-GMP-controlled biofilm production.},
journal = {NPJ biofilms and microbiomes},
volume = {6},
number = {1},
pages = {24},
doi = {10.1038/s41522-020-0134-1},
pmid = {32532998},
issn = {2055-5008},
support = {15-AXA-PDOC-037//AXA Research Fund (Le Fonds AXA pour la Recherche)/ ; ANR-10-INSB-04//Agence Nationale de la Recherche (French National Research Agency)/ ; },
abstract = {The zoonotic bacterium Leptospira interrogans is the aetiological agent of leptospirosis, a re-emerging infectious disease that is a growing public health concern. Most human cases of leptospirosis result from environmental infection. Biofilm formation and its contribution to the persistence of virulent leptospires in the environment or in the host have scarcely been addressed. Here, we examined spatial and time-domain changes in biofilm production by L. interrogans. Our observations showed that biofilm formation in L. interrogans is a highly dynamic process and leads to a polarized architecture. We notably found that the biofilm matrix is composed of extracellular DNA, which enhances the biofilm's cohesiveness. By studying L. interrogans mutants with defective diguanylate cyclase and phosphodiesterase genes, we show that biofilm production is regulated by intracellular levels of bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) and underpins the bacterium's ability to withstand a wide variety of simulated environmental stresses. Our present results show how the c-di-GMP pathway regulates biofilm formation by L. interrogans, provide insights into the environmental persistence of L. interrogans and, more generally, highlight leptospirosis as an environment-borne threat to human health.},
}
@article {pmid32532873,
year = {2020},
author = {Nagasawa, R and Sato, T and Nomura, N and Nakamura, T and Senpuku, H},
title = {Potential risk to spread resistant genes within the extracellular DNA-dependent biofilm of Streptococcus mutans in response to cell envelope stress induced by sub-MIC of bacitracin.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.00770-20},
pmid = {32532873},
issn = {1098-5336},
abstract = {Antibiotics are used to treat or prevent some types of bacterial infection. The inappropriate use of antibiotics unnecessarily promotes antibiotic resistance and increases resistant bacteria, and controlling these bacteria is difficult. While the emergence of drug-resistant bacteria is a serious problem, the behavior of drug-resistant bacteria is not fully understood. In this study, we investigated the behavior of Streptococcus mutans, a major etiological agent of dental caries that is resistant to bacitracin, which is a cell wall-targeting antibiotic, and focused on biofilm formation in the presence of bacitracin. S. mutans UA159 most strongly induced extracellular DNA (eDNA)-dependent biofilm formation in the presence of bacitracin at 1/8 minimum inhibitory concentration (MIC). The ΔmbrC and ΔmbrD mutant strains, which lack bacitracin resistance, also formed biofilms in the presence of bacitracin at 1/2 x MIC. This difference between the WT and the mutants was caused by the induction of atlA expression in the mid-log phase. We also revealed that rgp genes involved in the synthesis of rhamnose-glucose polysaccharide related to cell wall synthesis were downregulated by bacitracin. In addition, glucosyltransferase-I was also involved in eDNA-dependent biofilm formation. The biofilm led to increased transformation efficiencies and promoted horizontal gene transfer. Biofilms were also induced by ampicillin and vancomycin, antibiotics targeting cell wall synthesis, suggesting that cell envelope stress triggers biofilm formation. Therefore, the expression of the atlA and rgp genes is regulated by S. mutans, which forms eDNA-dependent biofilms, promoting horizontal gene transfer in response to cell envelope stress induced by sub-MICs of antibiotics.Importance Antibiotics have been reported to induce biofilm formation in many bacteria at sub-inhibitory concentrations. Accordingly, it is conceivable that the MIC against drug-sensitive bacteria may promote biofilm formation of resistant bacteria. Since drug-resistant bacteria have spread, it is important to understand the behavior of resistant bacteria. Streptococcus mutans is bacitracin-resistant, and the 1/8 x MIC of bacitracin, which is a cell wall-targeted antibiotic, induced eDNA-dependent biofilm formation. The ΔmbrC and ΔmbrD strains, which are not resistant to bacitracin, also formed biofilms in the presence of bacitracin at 1/2 x MIC, and both biofilms of wild and mutants promoted horizontal gene transfer. Another cell wall-targeted antibiotic, vancomycin, showed similar effects on biofilms and gene transfer as bacitracin. Thus, treatment with cell wall-targeted antibiotics may promote the spread of drug-resistant genes in biofilms. Therefore, the behavior of resistant bacteria in the presence of antibiotics at sub-MICs should be investigated when using antibiotics.},
}
@article {pmid32530919,
year = {2020},
author = {Harrison, JJ and Almblad, H and Irie, Y and Wolter, DJ and Eggleston, HC and Randall, TE and Kitzman, JO and Stackhouse, B and Emerson, JC and Mcnamara, S and Larsen, TJ and Shendure, J and Hoffman, LR and Wozniak, DJ and Parsek, MR},
title = {Elevated exopolysaccharide levels in Pseudomonas aeruginosa flagellar mutants have implications for biofilm growth and chronic infections.},
journal = {PLoS genetics},
volume = {16},
number = {6},
pages = {e1008848},
pmid = {32530919},
issn = {1553-7404},
abstract = {Pseudomonas aeruginosa colonizes the airways of cystic fibrosis (CF) patients, causing infections that can last for decades. During the course of these infections, P. aeruginosa undergoes a number of genetic adaptations. One such adaptation is the loss of swimming motility functions. Another involves the formation of the rugose small colony variant (RSCV) phenotype, which is characterized by overproduction of the exopolysaccharides Pel and Psl. Here, we provide evidence that the two adaptations are linked. Using random transposon mutagenesis, we discovered that flagellar mutations are linked to the RSCV phenotype. We found that flagellar mutants overexpressed Pel and Psl in a surface-contact dependent manner. Genetic analyses revealed that flagellar mutants were selected for at high frequencies in biofilms, and that Pel and Psl expression provided the primary fitness benefit in this environment. Suppressor mutagenesis of flagellar RSCVs indicated that Psl overexpression required the mot genes, suggesting that the flagellum stator proteins function in a surface-dependent regulatory pathway for exopolysaccharide biosynthesis. Finally, we identified flagellar mutant RSCVs among CF isolates. The CF environment has long been known to select for flagellar mutants, with the classic interpretation being that the fitness benefit gained relates to an impairment of the host immune system to target a bacterium lacking a flagellum. Our new findings lead us to propose that exopolysaccharide production is a key gain-of-function phenotype that offers a new way to interpret the fitness benefits of these mutations.},
}
@article {pmid32529892,
year = {2020},
author = {Muzammil, S and Khurshid, M and Nawaz, I and Siddique, MH and Zubair, M and Nisar, MA and Imran, M and Hayat, S},
title = {Aluminium oxide nanoparticles inhibit EPS production, adhesion and biofilm formation by multidrug resistant Acinetobacter baumannii.},
journal = {Biofouling},
volume = {36},
number = {4},
pages = {492-504},
doi = {10.1080/08927014.2020.1776856},
pmid = {32529892},
issn = {1029-2454},
abstract = {Acinetobacter baumannii is a biofilm forming multidrug resistant (MDR) pathogen responsible for respiratory tract infections. In this study, aluminium oxide nanoparticles (Al2O3 NPs) were synthesized and characterized by TEM and EDX and shown to be spherical shaped nanoparticles with a diameter < 10 nm. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) for the Al2O3 NPs ranged between 125 and 1,000 µg ml-1. Exposure to NPs caused cellular membrane disruption, indicated by an increase in cellular leakage of the contents. Biofilm inhibition was 11.64 to 70.2%, whereas attachment of bacteria to polystyrene surfaces was reduced to 48.8 to 51.9% in the presence of NPs. Nanoparticles also reduced extracellular polymeric substance production and the biomass of established biofilms. The data revealed the non-toxic nature of Al2O3 NPs up to a concentrations of 120 µg ml-1 in HeLa cell lines. These results demonstrate an effective and safer use of Al2O3 NPs against the MDR A. baumannii by targeting biofilm formation, adhesion and EPS production.},
}
@article {pmid32529277,
year = {2020},
author = {Eran, Z and Akçelik, M and Yazıcı, BC and Özcengiz, G and Akçelik, N},
title = {Regulation of biofilm formation by marT in Salmonella Typhimurium.},
journal = {Molecular biology reports},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11033-020-05573-6},
pmid = {32529277},
issn = {1573-4978},
support = {114Z871//TUBITAK/ ; },
abstract = {In this study, we aimed at identifying the regulatory role of marT gene, known as the regulator of misL, on 15 different biofilm-related genes in S. Typhimurium 14028 strain. We also tested the strains for their ability to form biofilm and determined the adherence characteristics of the wild type and the mutant strains of the organism on Caco-2 and HEp-2 cells. For comparative analyses of the candidate genes, individual gene mutations were created via antibiotic gene cassette insertion into each gene of interest. marT gene was cloned behind an arabinose inducible BAD promoter in order to control marT expression. This recombinant plasmid was transfer into each of the 15 mutant strains to investigate the level of expression of each single gene in the presence and absence of marT induction. Besides determination of variations in biofilm formation by each mutant strain, the attachment characteristics of them onto Caco-2 and HEp-2 cell lines were also reported. As a result of attachments experiments on polystyrene surfaces, it was determined that the biofilm production capacity of each mutant strain decreased in a statistically significant manner (p < 0.05). QRT-PCR trials indicated that the marT gene regulates the expression of 14 genes, namely fimA, fimD, fimF, fimH, stjB, stjC, csgA, csgD, ompC, sthB, sthE, rmbA, fliZ and yaiC, in a positive manner. QRT-PCR studies were also revealed that the MarT protein positively regulates its own promoter. When the adherence characteristics of the mutant strains and the wild-type were investigated by using Caco-2 and HEp-2 cells, it was determined that the single gene mutations did have no effect on bacterial adhesion. In view of our mutational analyses and biofilm formation studies, it was concluded that fliZ, ompC, rmbA, stjB and stjC genes are related with biofilm formation in Salmonella, besides other cellular functions of them. Taken together, our data suggested that the regulatory role of MarT protein is not only restricted to the regulation of misL gene expression, but it rather acts as a general regulator on the biofilm-related genes in Salmonella.},
}
@article {pmid32528421,
year = {2020},
author = {Liu, C and Sun, D and Zhu, J and Liu, J and Liu, W},
title = {The Regulation of Bacterial Biofilm Formation by cAMP-CRP: A Mini-Review.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {802},
pmid = {32528421},
issn = {1664-302X},
abstract = {Biofilms are communities of microorganisms that live in a self-produced extracellular matrix in order to survive in hostile environments. Second messengers, such as c-di-GMP and cAMP, participate in the regulation of biofilm formation. c-di-GMP is a major molecule that is involved in modulating the bacterial transition between a planktonic lifestyle and biofilm formation. Aside from regulating carbon catabolism repression in most bacteria, cAMP has also been found to mediate biofilm formation in many bacteria. Although the underlying mechanisms of biofilm formation mediated by cAMP-CRP have been well-investigated in several bacteria, the regulatory pathways of cAMP-CRP are still poorly understood compared to those of c-di-GMP. Moreover, some bacteria appear to form biofilm in response to changes in carbon source type or concentration. However, the relationship between the carbon metabolisms and biofilm formation remains unclear. This mini-review provides an overview of the cAMP-CRP-regulated pathways involved in biofilm formation in some bacteria. This information will benefit future investigations of the underlying mechanisms that connect between biofilm formation with nutrient metabolism, as well as the cross-regulation between multiple second messengers.},
}
@article {pmid32527216,
year = {2020},
author = {Bhardwaj, RG and Ellepolla, A and Drobiova, H and Karched, M},
title = {Biofilm growth and IL-8 &amp; TNF-α-inducing properties of Candida albicans in the presence of oral gram-positive and gram-negative bacteria.},
journal = {BMC microbiology},
volume = {20},
number = {1},
pages = {156},
pmid = {32527216},
issn = {1471-2180},
support = {SRUL 01/14//Kuwait University/ ; },
abstract = {BACKGROUND: Interaction of C. albicans with oral bacteria is crucial for its persistence, but also plays a potential role in the infection process. In the oral cavity, it grows as part of dental plaque biofilms. Even though growth and interaction of C. albicans with certain bacterial species has been studied, little is known about its biofilm growth in vitro in the simultaneous presence of Gram-negative and Gram-positive bacteria. The aim was to evaluate the growth of C. albicans in polymicrobial biofilms comprising oral Gram-negative and Gram-positive bacteria. Further, we also aimed to assess the potential of C. albicans in the Candida-bacteria polymicrobial biofilm to elicit cytokine gene expression and cytokine production from human blood cells.<br><br>RESULTS: C. albicans cell counts increased significantly up to 48 h in polymicrobial biofilms (p < 0.05), while the bacterial counts in the same biofilms increased only marginally as revealed by qPCR absolute quantification. However, the presence of bacteria in the biofilm did not seem to affect the growth of C. albicans. Expression of IL-8 gene was significantly (p < 0.05) higher upon stimulation from biofilm-supernatants than from biofilms in polymicrobial setting. On the contrary, TNF-α expression was significantly higher in biofilms than in supernatants but was very low (1-4 folds) in the monospecies biofilm of C. albicans. ELISA cytokine quantification data was in agreement with mRNA expression results.<br><br>CONCLUSION: Persistence and enhanced growth of C. albicans in polymicrobial biofilms may imply that previously reported antagonistic effect of A. actinomycetemcomitans was negated. Increased cytokine gene expression and cytokine production induced by Candida-bacteria polymicrobial biofilms and biofilm supernatants suggest that together they possibly exert an enhanced stimulatory effect on IL-8 and TNF-α production from the host.},
}
@article {pmid32526346,
year = {2020},
author = {Bhadila, G and Wang, X and Zhou, W and Menon, D and Melo, MAS and Montaner, S and Oates, TW and Weir, MD and Sun, J and Xu, HHK},
title = {Novel low-shrinkage-stress nanocomposite with remineralization and antibacterial abilities to protect marginal enamel under biofilm.},
journal = {Journal of dentistry},
volume = {},
number = {},
pages = {103406},
doi = {10.1016/j.jdent.2020.103406},
pmid = {32526346},
issn = {1879-176X},
abstract = {OBJECTIVES: Polymerization shrinkage stress may lead to marginal damage, microleakage and failure of composite restorations. The objectives of this study were to : (1) develop a novel nanocomposite with low-shrinkage-stress, antibacterial and remineralization properties to reduce marginal enamel demineralization under biofilms; (2) evaluate the mechanical properties of the composite and calcium (Ca) and phosphate (P) ion release; and (3) investigate the cytotoxicity of the new low-shrinkage-stress monomer in vitro.<br><br>METHODS: The low-shrinkage-stress resin consisted of urethane dimethacrylate (UDMA) and triethylene glycol divinylbenzyl ether (TEG-DVBE), and 3 % dimethylaminohexadecyl methacrylate (DMAHDM) and 20 % calcium phosphate nanoparticles (NACP) were added. Mechanical properties, polymerization shrinkage stress, and degree of conversion were evaluated. The growth of Streptococcus mutans (S. mutans) on enamel slabs with different composites was assessed. Ca and P ion releases and monomer cytotoxicity were measured.<br><br>RESULTS: Composite with DMAHDM and NACP had flexural strength of 84.9 ± 10.3 MPa (n = 6), matching that of a commercial control composite. Adding 3 % DMAHDM did not negatively affect the composite ion release. Under S. mutans biofilm, the marginal enamel hardness was 1.2 ± 0.1 GPa for the remineralizing and antibacterial group, more than 2-fold the 0.5 ± 0.07 GPa for control (p < 0.05). The polymerization shrinkage stress of the new composite was 40 % lower than that of traditional composite control (p < 0.05). The new monomers had fibroblast viability similar to that of commercial control (p > 0.1).<br><br>CONCLUSION: A novel low-shrinkage-stress nanocomposite was developed with remineralizing and antibacterial properties. This new composite is promising to inhibit recurrent caries at the restoration margins by reducing polymerization stress and protecting enamel hardness.},
}
@article {pmid32523805,
year = {2020},
author = {Lin, MF and Lin, YY and Lan, CY},
title = {Characterization of biofilm production in different strains of Acinetobacter baumannii and the effects of chemical compounds on biofilm formation.},
journal = {PeerJ},
volume = {8},
number = {},
pages = {e9020},
pmid = {32523805},
issn = {2167-8359},
abstract = {Acinetobacter baumannii, an important emerging pathogen of nosocomial infections, is known for its ability to form biofilms. Biofilm formation increases the survival rate of A. baumannii on dry surfaces and may contribute to its persistence in the hospital environment, which increases the probability of nosocomial infections and outbreaks. This study was undertaken to characterize the biofilm production of different strains of A. baumannii and the effects of chemical compounds, especially antibiotics, on biofilm formation. In this study, no statistically significant relationship was observed between the ability to form a biofilm and the antimicrobial susceptibility of the A. baumannii clinical isolates. Biofilm formation caused by A. baumannii ATCC 17978 after gene knockout of two-component regulatory system gene baeR, efflux pump genes emrA/emrB and outer membrane coding gene ompA revealed that all mutant strains had less biofilm formation than the wild-type strain, which was further supported by the images from scanning electron microscopy and confocal laser scanning microscopy. The addition of amikacin, colistin, LL-37 or tannic acid decreased the biofilm formation ability of A. baumannii. In contrast, the addition of lower subinhibitory concentration tigecycline increased the biofilm formation ability of A. baumannii. Minimum biofilm eradication concentrations of amikacin, imipenem, colistin, and tigecycline were increased obviously for both wild type and multidrug resistant clinical strain A. baumannii VGH2. In conclusion, the biofilm formation ability of A. baumannii varied in different strains, involved many genes and could be influenced by many chemical compounds.},
}
@article {pmid32523574,
year = {2020},
author = {Lohse, MB and Gulati, M and Craik, CS and Johnson, AD and Nobile, CJ},
title = {Combination of Antifungal Drugs and Protease Inhibitors Prevent Candida albicans Biofilm Formation and Disrupt Mature Biofilms.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {1027},
pmid = {32523574},
issn = {1664-302X},
abstract = {Biofilms formed by the fungal pathogen Candida albicans are resistant to many of the antifungal agents commonly used in the clinic. Previous reports suggest that protease inhibitors, specifically inhibitors of aspartyl proteases, could be effective antibiofilm agents. We screened three protease inhibitor libraries, containing a total of 80 compounds for the abilities to prevent C. albicans biofilm formation and to disrupt mature biofilms. The compounds were screened individually and in the presence of subinhibitory concentrations of the most commonly prescribed antifungal agents for Candida infections: fluconazole, amphotericin B, or caspofungin. Although few of the compounds affected biofilms on their own, seven aspartyl protease inhibitors inhibited biofilm formation when combined with amphotericin B or caspofungin. Furthermore, nine aspartyl protease inhibitors disrupted mature biofilms when combined with caspofungin. These results suggest that the combination of standard antifungal agents together with specific protease inhibitors may be useful in the prevention and treatment of C. albicans biofilm infections.},
}
@article {pmid32520698,
year = {2020},
author = {Koza, A and Jerdan, R and Cameron, S and Spiers, AJ},
title = {Three biofilm types produced by a model pseudomonad are differentiated by structural characteristics and fitness advantage.},
journal = {Microbiology (Reading, England)},
volume = {},
number = {},
pages = {},
doi = {10.1099/mic.0.000938},
pmid = {32520698},
issn = {1465-2080},
abstract = {Model bacterial biofilm systems suggest that bacteria produce one type of biofilm, which is then modified by environmental and physiological factors, although the diversification of developing populations might result in the appearance of adaptive mutants producing altered structures with improved fitness advantage. Here we compare the air-liquid (A-L) interface viscous mass (VM) biofilm produced by Pseudomonas fluorescens SBW25 and the wrinkly spreader (WS) and complementary biofilm-forming strain (CBFS) biofilm types produced by adaptive SBW25 mutants in order to better understand the link between these physical structures and the fitness advantage they provide in experimental microcosms. WS, CBFS and VM biofilms can be differentiated by strength, attachment levels and rheology, as well as by strain characteristics associated with biofilm formation. Competitive fitness assays demonstrate that they provide similar advantages under static growth conditions but respond differently to increasing levels of physical disturbance. Pairwise competitions between biofilms suggest that these strains must be competing for at least two growth-limiting resources at the A-L interface, most probably O2 and nutrients, although VM and CBFS cells located lower down in the liquid column might provide an additional fitness advantage through the colonization of a less competitive zone below the biofilm. Our comparison of different SBW25 biofilm types illustrates more generally how varied biofilm characteristics and fitness advantage could become among adaptive mutants arising from an ancestral biofilm-forming strain and raises the question of how significant these changes might be in a range of medical, biotechnological and industrial contexts where diversification and change may be problematic.},
}
@article {pmid32520436,
year = {2020},
author = {Smith, S and Waters, V and Jahnke, N and Ratjen, F},
title = {Standard versus biofilm antimicrobial susceptibility testing to guide antibiotic therapy in cystic fibrosis.},
journal = {The Cochrane database of systematic reviews},
volume = {6},
number = {},
pages = {CD009528},
doi = {10.1002/14651858.CD009528.pub5},
pmid = {32520436},
issn = {1469-493X},
abstract = {BACKGROUND: Clinicians typically select the antibiotics used to treat pulmonary infections in people with cystic fibrosis based on the results of antimicrobial susceptibility testing performed on bacteria traditionally grown in a planktonic mode (grown in a liquid). However, there is considerable evidence to suggest that Pseudomonas aeruginosa actually grows in a biofilm (or slime layer) in the airways of people with cystic fibrosis with chronic pulmonary infections. Therefore, choosing antibiotics based on biofilm rather than conventional antimicrobial susceptibility testing could potentially improve response to treatment of Pseudomonas aeruginosa in people with cystic fibrosis. This is an update of a previously published Cochrane Review.<br><br>OBJECTIVES: To compare biofilm antimicrobial susceptibility testing-driven therapy to conventional antimicrobial susceptibility testing-driven therapy in the treatment of Pseudomonas aeruginosa infection in people with cystic fibrosis.<br><br>SEARCH METHODS: We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Most recent search: 07 April 2020. We also searched two ongoing trials registries and the reference lists of relevant articles and reviews. Most recent searches: 07 April 2020 and 05 September 2017.<br><br>SELECTION CRITERIA: Randomized controlled trials (RCTs) of antibiotic therapy based on biofilm antimicrobial susceptibility testing compared to antibiotic therapy based on conventional antimicrobial susceptibility testing in the treatment of Pseudomonas aeruginosa pulmonary infection in people with cystic fibrosis.<br><br>DATA COLLECTION AND ANALYSIS: Two authors independently selected RCTs, assessed their risk of bias and extracted data from eligible trials. Additionally, the review authors contacted the trial investigators to obtain further information. The quality of the evidence was assessed using the GRADE criteria.<br><br>MAIN RESULTS: The searches identified two multicentre, double-blind RCTs eligible for inclusion in the review with a total of 78 participants (adults and children); one RCT was undertaken in people who were clinically stable, the second was in people experiencing pulmonary exacerbations. Both RCTs prospectively assessed whether the use of biofilm antimicrobial susceptibility testing improved microbiological and clinical outcomes in participants with cystic fibrosis who were infected with Pseudomonas aeruginosa. The primary outcome was the change in sputum Pseudomonas aeruginosa density from the beginning to the end of antibiotic therapy. Although the intervention was shown to be safe, the data from these two RCTs did not provide evidence that biofilm susceptibility testing was superior to conventional susceptibility testing either in terms of microbiological or lung function outcomes. One of the trials also measured risk and time to subsequent exacerbation as well as quality of life measures and did not demonstrate any difference between groups in these outcomes. Both RCTs had an overall low risk of bias and the quality of the evidence using GRADE criteria was deemed to be moderate to high for the outcomes selected.<br><br>AUTHORS' CONCLUSIONS: The current evidence is insufficient to recommend choosing antibiotics based on biofilm antimicrobial susceptibility testing rather than conventional antimicrobial susceptibility testing in the treatment of Pseudomonas aeruginosa pulmonary infections in people with cystic fibrosis. Biofilm antimicrobial susceptibility testing may be more appropriate in the development of newer, more effective formulations of drugs which can then be tested in clinical trials.},
}
@article {pmid32519201,
year = {2020},
author = {Anjum, MM and Patel, KK and Dehari, D and Pandey, N and Tilak, R and Agrawal, AK and Singh, S},
title = {Anacardic acid encapsulated solid lipid nanoparticles for Staphylococcus aureus biofilm therapy: chitosan and DNase coating improves antimicrobial activity.},
journal = {Drug delivery and translational research},
volume = {},
number = {},
pages = {},
doi = {10.1007/s13346-020-00795-4},
pmid = {32519201},
issn = {2190-3948},
support = {DST/SSTP/UP/2013-14/12TH PLAN/132//Ministry of Science and Technology (India)/ ; },
abstract = {Biofilm mediated bacterial infections are the key factors in the progression of infectious diseases due to the evolution of antimicrobial resistance. Traditional therapy involving antibiotics is not adequate enough for treatment of such infections due to the increased resistance triggered by biofilm. To overcome this challenge, we developed anacardic acid (Ana) loaded solid lipid nanoparticles (SLNs), further coated with chitosan and DNase (Ana-SLNs-CH-DNase). The DNase coating was hypothesized to degrade the e-DNA, while chitosan was coated to yield positively charged SLNs with additional adhesion to biofilms. The SLNs were developed using homogenization method and further evaluated for particle size, polydispersity index, zeta potential, and entrapment efficiency. Drug excipient compatibility was confirmed by using FT-IR study, while encapsulation of Ana in SLNs was confirmed by X-ray diffraction study. The SLNs demonstrated sustained release for up to 24 h and excellent stability at room temperature for up to 3 months. The developed SLNs were found non-toxic against human immortalized keratinocyte (HaCaT) cells while demonstrated remarkably higher antimicrobial efficacy against Staphylococcus aureus. Excellent effect of the developed SLNs on minimum biofilm inhibition concentration and minimum biofilm eradication concentration further confirmed the superiority of the developed formulation strategy. A significant (p < 0.05) reduction in biofilm thickness and biomass, as confirmed by confocal laser scanning microscopy, was observed in the case of developed SLNs in comparison with control. Cumulatively, the results suggest the enhanced efficacy of the developed formulation strategy to overcome the biofilm-mediated antimicrobial resistance. Graphical abstract.},
}
@article {pmid32518594,
year = {2020},
author = {Jasemi, S and Emaneini, M and Fazeli, MS and Ahmadinejad, Z and Nomanpour, B and Sadeghpour Heravi, F and Sechi, LA and Feizabadi, MM},
title = {Toxigenic and non-toxigenic patterns I, II and III and biofilm-forming ability in Bacteroides fragilis strains isolated from patients diagnosed with colorectal cancer.},
journal = {Gut pathogens},
volume = {12},
number = {},
pages = {28},
pmid = {32518594},
issn = {1757-4749},
abstract = {Background: Enterotoxigenic Bacteroides fragilis (ETBF) associated with the initiation and progression of colorectal cancer (CRC) has been alarmingly reported all over the world. In this study, simultaneous investigation of toxigenic and non-toxigenic patterns I, II and III and biofilm formation ability of Bacteroides fragilis isolated from patients with colorectal cancer was performed.<br><br>Methods: Thirty-one patients diagnosed with CRC and thirty-one control subjects were recruited in this study. Specimens were cultured on BBE and BBA culture media. Classical phenotypic identification tests and PCR was performed to verify Bacteroides fragilis presence. Also, biofilm-forming ability and expression of bft gene were assessed under biofilm and planktonic forms.<br><br>Results: A total of 68 B.fragilis was isolated from all colorectal tissue, of which 13 isolates (19.1%) (11 isolates from CRC and 2 from normal tissue) were positive for bft gene. The abundance patterns of I, II and III were as follow in descending order; pattern I > pattern III > pattern II in CRC subjects and pattern II > pattern III > pattern I in normal tissues. Also, pattern I showed higher biofilm formation ability compared to other patterns. Toxin expression was significantly reduced in biofilm form comparing with planktonic form.<br><br>Conclusions: Based on our findings, there was a difference between the abundance of patterns I, II, and III and biofilm formation in isolates obtained from CRC and normal tissues. Biofilm formation ability and toxin encoding gene (bft) are two main virulence factors in B. fragilis pathogenicity which require more investigation to treat B. fragilis infections effectively.},
}
@article {pmid32518329,
year = {2020},
author = {El Zawawy, NA and El-Shenody, RA and Ali, SS and El-Shetehy, M},
title = {A novel study on the inhibitory effect of marine macroalgal extracts on hyphal growth and biofilm formation of candidemia isolates.},
journal = {Scientific reports},
volume = {10},
number = {1},
pages = {9339},
doi = {10.1038/s41598-020-66000-1},
pmid = {32518329},
issn = {2045-2322},
abstract = {Biofilm formation and hyphal growth are considered to be the most serious virulence factors of Candida species in blood causing candidemia infections, which are difficult to treat due to the spread of resistant Candida isolates to most antifungal drugs. Therefore, in this study, we investigated the effect of different types and concentrations of selected macroalgal extracts from Cladostephus spongiosus (Phaeophyta), Laurencia papillosa (Rhodophyta), and Codium arabicum (Chlorophyta) in inhibiting those virulence factors of the isolated Candida. Acetone extract of C. spongiosus (AECS) showed a stronger anticandidal activity against the selected strains than ethanol extract. Candida krusei was the highest biofilm producer among the selected isolates. AECS showed an inhibition of C. krusei biofilm formation as well as a reduction in the viability of preformed biofilms. Also, AECS reduced various sugars in the candidal exo-polysaccaride layer (EPS). Scanning electron microscopy (SEM) and light microscopic images revealed an absence of hyphae and an alteration in the morphology of biofilm cells when treated with AECS. Moreover, AECS downregulated the expression of hyphal specific genes, hyphal wall protein 1 (HWP1), Agglutinin-like protein 1 (ALS1) and fourth secreted aspartyl proteinase (SAP4), which confirmed the inhibitory effect of AECS on hyphal growth and biofilm formation. Gas chromatography-mass spectrophotometer (GC-MS) analysis of AECS showed three major compounds, which were non-existent in the ethanol extract, and might be responsible for the anticandidal activity; these revealed compounds were 4-hydroxy-4-methyl-2-pentanone, n-hexadecenoic acid, and phenol, 2-methoxy-4-(2-propenyl). These active compounds of AECS may be promising for future pharmaceutical applications in the treatment of candidemia.},
}
@article {pmid32518194,
year = {2020},
author = {Anderton, CR and Mobberley, JM and Cole, JK and Nunez, JR and Starke, R and Boaro, AA and Yesiltepe, Y and Morton, BR and Cory, AB and Cardamone, HC and Hofmockel, KS and Lipton, MS and Moran, JJ and Renslow, RS and Fredrickson, JK and Lindemann, SR},
title = {Nitrogen Source Governs Community Carbon Metabolism in a Model Hypersaline Benthic Phototrophic Biofilm.},
journal = {mSystems},
volume = {5},
number = {3},
pages = {},
pmid = {32518194},
issn = {2379-5077},
abstract = {Increasing anthropogenic inputs of fixed nitrogen are leading to greater eutrophication of aquatic environments, but it is unclear how this impacts the flux and fate of carbon in lacustrine and riverine systems. Here, we present evidence that the form of nitrogen governs the partitioning of carbon among members in a genome-sequenced, model phototrophic biofilm of 20 members. Consumption of NO3- as the sole nitrogen source unexpectedly resulted in more rapid transfer of carbon to heterotrophs than when NH4+ was also provided, suggesting alterations in the form of carbon exchanged. The form of nitrogen dramatically impacted net community nitrogen, but not carbon, uptake rates. Furthermore, this alteration in nitrogen form caused very large but focused alterations to community structure, strongly impacting the abundance of only two species within the biofilm and modestly impacting a third member species. Our data suggest that nitrogen metabolism may coordinate coupled carbon-nitrogen biogeochemical cycling in benthic biofilms and, potentially, in phototroph-heterotroph consortia more broadly. It further indicates that the form of nitrogen inputs may significantly impact the contribution of these communities to carbon partitioning across the terrestrial-aquatic interface.IMPORTANCE Anthropogenic inputs of nitrogen into aquatic ecosystems, and especially those of agricultural origin, involve a mix of chemical species. Although it is well-known in general that nitrogen eutrophication markedly influences the metabolism of aquatic phototrophic communities, relatively little is known regarding whether the specific chemical form of nitrogen inputs matter. Our data suggest that the nitrogen form alters the rate of nitrogen uptake significantly, whereas corresponding alterations in carbon uptake were minor. However, differences imposed by uptake of divergent nitrogen forms may result in alterations among phototroph-heterotroph interactions that rewire community metabolism. Furthermore, our data hint that availability of other nutrients (i.e., iron) might mediate the linkage between carbon and nitrogen cycling in these communities. Taken together, our data suggest that different nitrogen forms should be examined for divergent impacts on phototrophic communities in fluvial systems and that these anthropogenic nitrogen inputs may significantly differ in their ultimate biogeochemical impacts.},
}
@article {pmid32517335,
year = {2020},
author = {Behzadi, P and Urbán, E and Gajdács, M},
title = {Association between Biofilm-Production and Antibiotic Resistance in Uropathogenic Escherichia coli (UPEC): An In Vitro Study.},
journal = {Diseases (Basel, Switzerland)},
volume = {8},
number = {2},
pages = {},
doi = {10.3390/diseases8020017},
pmid = {32517335},
issn = {2079-9721},
abstract = {Urinary tract infections (UTIs) are among the most common infections requiring medical attention worldwide. The production of biofilms is an important step in UTIs, not only from a mechanistic point of view, but this may also confer additional resistance, distinct from other aspects of multidrug resistance (MDR). A total of two hundred and fifty (n = 250) Escherichia coli isolates, originating from clean-catch urine samples, were included in this study. The isolates were classified into five groups: wild-type, ciprofloxacin-resistant, fosfomycin-resistant, trimethoprim-sulfamethoxazole-resistant and extended spectrum β-lactamase (ESBL)-producing strains. The bacterial specimens were cultured using eosine methylene blue agar and the colony morphology of isolates were recorded. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method and E-tests. Biofilm-formation of the isolates was carried out with the crystal violet tube-adherence method. n = 76 isolates (30.4%) produced large colonies (>3 mm), mucoid variant colonies were produced in n = 135 cases (54.0%), and n = 119 (47.6%) were positive for biofilm formation. The agreement (i.e., predictive value) of mucoid variant colonies in regard to biofilm production in the tube-adherence assay was 0.881 overall. Significant variation was seen in the case of the group of ESBL-producers in the ratio of biofilm-producing isolates. The relationship between biofilm-production and other resistance determinants has been extensively studied. However, no definite conclusion can be reached from the currently available data.},
}
@article {pmid32517201,
year = {2020},
author = {Olszewska, MA and Gędas, A and Simões, M},
title = {The Effects of Eugenol, Trans-Cinnamaldehyde, Citronellol, and Terpineol on Escherichia coli Biofilm Control as Assessed by Culture-Dependent and -Independent Methods.},
journal = {Molecules (Basel, Switzerland)},
volume = {25},
number = {11},
pages = {},
pmid = {32517201},
issn = {1420-3049},
support = {PTDC/BII-BTI/30219/2017 - POCI-01-0145-FEDER-030219//Fundação para a Ciência e a Tecnologia/ ; },
abstract = {Bacterial biofilms contribute to problems with preserving food hygiene, jeopardizing any conventional intervention method used by the food industry. Hence, the approach of using essential oil (EO) compounds effective in biofilm control has considerable merit and deserves in-depth research. In this study, the effect of selected EO compounds (eugenol, trans-cinnamaldehyde, citronellol, and terpineol) was assessed on Escherichia coli biofilm control by plate count, resazurin assay, and Syto® 9/PI (-/propidium iodide) staining coupled with flow cytometry (FCM) and confocal laser scanning microscopy (CLSM). The selected EO compounds effectively inhibited the growth of planktonic E. coli at low concentrations of 3-5 mM, revealing a high antimicrobial activity. EO compounds markedly interfered with biofilms too, with trans-cinnamaldehyde causing the most prominent effects. Its antibiofilm activity was manifested by a high reduction of cell metabolic activity (>60%) and almost complete reduction in biofilm cell culturability. In addition, almost 90% of the total cells had perturbed cell membranes. Trans-cinnamaldehyde further impacted the cell morphology resulting in the filamentation and, thus, in the creation of a mesh network of cells. Citronellol scored the second in terms of the severity of the observed effects. However, most of all, it strongly prevented native microcolony formation. Eugenol and terpineol also affected the formation of a typical biofilm structure; however, small cell aggregates were still repeatedly found. Overall, eugenol caused the mildest impairment of cell membranes where 50% of the total cells showed the Syto® 9+/PI- pattern coupled with healthy cells and another 48% with injured cells (the Syto® 9+/PI+). For terpineol, despite a similar percentage of healthy cells, another 45% was shared between moderately (Syto® 9+PI+) and heavily (Syto® 9-PI+) damaged cells. The results highlight the importance of a multi-method approach for an accurate assessment of EO compounds' action against biofilms and may help develop better strategies for their effective use in the food industry.},
}
@article {pmid32516724,
year = {2020},
author = {Tran, TN and Kim, DG and Ko, SO},
title = {Efficient removal of 17α-ethinylestradiol from secondary wastewater treatment effluent by a biofilm process incorporating biogenic manganese oxide and Pseudomonas putida strain MnB1.},
journal = {Journal of hazardous materials},
volume = {398},
number = {},
pages = {122810},
doi = {10.1016/j.jhazmat.2020.122810},
pmid = {32516724},
issn = {1873-3336},
abstract = {This study proposes a biofilm process to immobilize biogenic manganese oxide (BMO) and Pseudomonas putida MnB1 (BMO-MnB1), which shows excellent synergistic effects for 17α-ethinylestradiol (EE2) from secondary wastewater treatment effluent (WWTE). Modified granular activated carbon (M-GAC) was used as the packing carrier, inoculated with Pseudomonas putida MnB1 and Mn(II) to form the BMO-MnB1 biofilm. Feasibility tests were performed to compare the EE2 removal efficiency with that of the conventional biofilm process (BAC) for heterogeneous microbial communities. Results show that in the BAC, EE2 was removed mainly by adsorption, with biodegradation contributing only slightly to the overall performance. In contrast, the BMO-MnB1 biofilter outperformed the BAC. Furthermore, less than 4% of the total EE2 removed was extracted from the biofilter medium over 150 days of operation, confirming that EE2 was biodegraded by P. putida MnB1 or chemically oxidized by BMO. Our results suggest that BMO-MnB1 biofilm processes have high potential for practical applications in removal of endocrine disrupting compounds from wastewater effluent.},
}
@article {pmid32516672,
year = {2020},
author = {Huang, S and Song, Q and Li, Q and Zhang, H and Luo, X and Zheng, Z},
title = {Damage of heavy metals to Vallisneria natans (V. natans) and characterization of microbial community in biofilm.},
journal = {Aquatic toxicology (Amsterdam, Netherlands)},
volume = {225},
number = {},
pages = {105515},
doi = {10.1016/j.aquatox.2020.105515},
pmid = {32516672},
issn = {1879-1514},
abstract = {Heavy metals can cause a significant damage to submerged macrophytes and affect its periphyton biofilms in aquatic environments. This study investigated the effects of heavy metals such as copper (Cu), lead (Pb), cadmium (Cd) and their mixture on physiological and biochemical responses and ultrastructure characteristics of Vallisneria natans (V. natans). Furthermore, differences in structures of microbial communities were observed in biofilms. The results showed that Cu2+, Pb2+, Cd2+ and their mixture could destroy cell structure and photosynthetic system, and directly caused oxidative damage to submerged macrophyte and induced antioxidant enzyme system. In general, biomass and total chlorophyll content of V. natans noticeably decreased, while the activities of superoxide dismutase, peroxidase and catalase were enhanced by heavy metal stress inducement in restricted range, and the malondialdehyde content increased with the aggravation of the damage. The single heavy metal stress played a negative impact, however, the combined stress was not always synergistic effects on plants. High-throughput sequencing analysis suggested that heavy metals changed the abundance and structure of the microbial biofilm community. Proteobacteria and Bacteroidete were the dominant bacteria under heavy metal stress and other species and abundance of bacteria such as Firmicute, Cyanobacteria, Chloroflexi, Actinobacteria, Verrucomicrobia, Acidobacteria, Deinococcus-Thermus, Chlamydiae were also present. These findings provided useful information for further understanding about submerged macrophytes and periphyton biofilms responsed to heavy metal stress in aquatic environments in the future.},
}
@article {pmid32515601,
year = {2020},
author = {Mizan, MFR and Ashrafudoulla, M and Hossain, MI and Cho, HR and Ha, SD},
title = {Effect of essential oils on pathogenic and biofilm-forming Vibrio parahaemolyticus strains.},
journal = {Biofouling},
volume = {36},
number = {4},
pages = {467-478},
doi = {10.1080/08927014.2020.1772243},
pmid = {32515601},
issn = {1029-2454},
abstract = {In this study, the effect of three essential oils (EOs) - clove oil (CO), thyme oil (TO), and garlic oil (GO), which are generally recognized as safe - on the planktonic growth, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), motility, biofilm formation, and quorum sensing (QS) of Vibrio parahaemolyticus was investigated. All three EOs showed bacteriostatic activity, with MICs in the range 0.02%-0.09% (v/v). CO and TO completely controlled planktonic growth at 0.28% and 0.08% (v/v), which is four times their MIC (4 × MIC), after 10 min, whereas GO completely controlled growth at 0.36% (v/v) (4 × MIC) after treatment for 20 min. V. parahaemolyticus motility was significantly reduced by all three EOs at 4 × MIC (0.28% for CO, 0.08% for TO, and 0.36% for GO), whereas QS was controlled and biofilm formation reduced by all three EOs at 8 × MIC (0.56% for CO, 0.16% for TO, and 0.72% for GO) after 30 min of treatment. These results suggest that CO, TO, and GO have a significant inhibitory effect on V. parahaemolyticus cells in biofilm sand thus represent a promising strategy for improving food safety. These results provide the evidence required to encourage further research into the practical use of the proposed EOs in food preparation processes.},
}
@article {pmid32515418,
year = {2020},
author = {Carvalho, TS and Halter, JE and Muçolli, D and Lussi, A and Eick, S and Baumann, T},
title = {Pellicle Modification with Casein and Mucin Does Not Promote In Vitro Bacterial Biofilm Formation.},
journal = {Oral health &amp; preventive dentistry},
volume = {18},
number = {3},
pages = {475-483},
doi = {10.3290/j.ohpd.a43351},
pmid = {32515418},
issn = {1757-9996},
mesh = {Biofilms ; *Caseins ; Dental Enamel ; Dental Pellicle ; Humans ; *Mucins ; Saliva ; },
abstract = {PURPOSE: During biofilm formation, bacterial species do not attach directly onto the enamel surface, but rather onto the salivary pellicle. Salivary pellicle modification with casein and mucin can hinder erosive demineralisation of the enamel, but it should also not promote bacterial adhesion. The aim of our study was to assess whether salivary pellicle modification with casein, or mucin, or a mixture of both proteins (casein and mucin) influence bacterial adhesion, biofilm diversity, metabolism and composition, or enamel demineralisation, after incubation in: (a) a single bacterial model; (b) a five-species biofilm model; or (c) biofilm reformation using the five-species biofilm model after removal of initial biofilm with toothbrushing.<br><br>MATERIALS AND METHODS: Enamel specimens were prepared from human molars. Whole-mouth stimulated human saliva was used for pellicle formation. Four pellicle modification groups were established: control (non-modified pellicle); casein - modified with 0.5% casein; mucin - modified with 0.5% mucin; casein and mucin - modified with 0.5% casein and 0.5% mucin. Bacterial adhesion, biofilm diversity, metabolic activity, biofilm mass, and demineralisation (surface hardness) of enamel were assessed after incubation in bacterial broths after 6 h or 24 h.<br><br>RESULTS: After 24 h incubation in the five-species biofilm model, the mucin group presented significantly lower biofilm mass than the control (p = 0.028) and the casein and mucin (p = 0.030) groups. No other differences between the groups were observed in any of the other experimental procedures.<br><br>CONCLUSION: Pellicle modification with casein and mucin does not promote in vitro bacterial biofilm formation.},
}
@article {pmid32512756,
year = {2020},
author = {Kaoukab-Raji, A and Biskri, L and Allaoui, A},
title = {Inactivation of the sfgtr4 Gene of Shigella flexneri Induces Biofilm Formation and Affects Bacterial Pathogenicity.},
journal = {Microorganisms},
volume = {8},
number = {6},
pages = {},
doi = {10.3390/microorganisms8060841},
pmid = {32512756},
issn = {2076-2607},
support = {FRSM: 3.4.623.06 and 3.4556.11//Belgian FRSM (: conventions: 3.4.623.06 and 3.4556.11)/ ; },
abstract = {Biofilm formation is a significant cause for the environmental persistence of foodborne pathogens. This phenomenon remains misunderstood in Shigellaflexneri whose pathogenicity is mainly associated with the virulence plasmid pWR100. Sequence analysis of the latter predicts a putative lipopolysaccharides (LPS) glycosyltransferase (Gtr) encoded by Sfgtr4, which is the second gene of the SfpgdA-orf186-virK-msbB2 locus. We demonstrated here that purified SfGtr4 exhibited a Gtr activity in vitro by transferring glucose to lipid A. To establish the role of SfGtr4 in virulence, we generated a Sfgtr4 mutant and assessed its phenotype in vitro. Sfgtr4 mutant significantly reduced HeLa cells invasion without impairing type III effectors secretion, increased susceptibility to lysozyme degradation, and enhanced bacterial killing by polymorphonuclear neutrophils (PMNs). SfGtr4 is related to proteins required in biofilm formation. We established conditions whereby wild-type Shigella formed biofilm and revealed that its appearance was accelerated by the Sfgtr4 mutant. Additional phenotypical analysis revealed that single SfpdgA and double SfpgdA-Sfgtr4 mutants behaved similarly to Sfgtr4 mutant. Furthermore, a molecular interaction between SfGtr4 and SfPgdA was identified. In summary, the dual contribution of SfGtr4 and SfPgdA to the pathogenicity and the regulation biofilm formation by S. flexneri was demonstrated here.},
}
@article {pmid32512247,
year = {2020},
author = {Leelanarathiwat, K and Katsuta, Y and Katsuragi, H and Watanabe, F},
title = {Antibacterial activity of blue high-power light-emitting diode-activated flavin mononucleotide against Staphylococcus aureus biofilm on a sandblasted and etched surface.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {101855},
doi = {10.1016/j.pdpdt.2020.101855},
pmid = {32512247},
issn = {1873-1597},
abstract = {BACKGROUND: Because of high affinity to the titanium implant surface, Staphylococcus aureus (S. aureus) has been reported as key microorganism that cause the peri-implantitis, even though it is not the typical periodontal pathogenic bacterial strain. The aim of this study was to evaluate the antibacterial property of the aPDT device, using blue high-power LED light activated flavin mononucleotide, comparing to the previously proven aPDT method using methylene blue and red laser on S. aureus biofilm.<br><br>METHODS: Commercial pure titanium grade 4 modified surface with SLA were used to form S. aureus biofilm for 48 h. Two aPDT systems were used in this study; 1) HELBO®Blue Photosensitizer (Bredent medical), which is methylene blue (MB) activated by 670-nm red diode laser and 2) FotoSan® Blue agent Gel (CMS Dental), which contains flavin mononucleotide (FMN) activated by FotoSan® BLUE LAD (Light Activated Disinfection) light. The antibacterial tests were performed by total viable count, crystal violet assay, and direct observation methods.<br><br>RESULTS: Using the light activated-PS, the log reduction in CFU/ml compared to non-treatment was 1.23 ± 0.19 log10 and 1.23 ± 0.12 log10 (about 93% of reduction) for MB and FMN, respectively. The significant difference in the reduction could be determined when comparing with using only light. (p < 0.01) Regarding two aPDT systems, the decrease in amount of bacteria after treatment was not significantly different. (p > 0.05) CONCLUSION: The antibacterial activities of aPDT using blue high-power LED light activated flavin mononucleotide on S. aureus biofilm was comparable to those of previous research supporting aPDT using photoactivated MB.},
}
@article {pmid32510928,
year = {2020},
author = {Rouillard, KR and Markovetz, MR and Bacudio, LG and Hill, DB and Schoenfisch, MH},
title = {Pseudomonas aeruginosa Biofilm Eradication via Nitric Oxide-Releasing Cyclodextrins.},
journal = {ACS infectious diseases},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsinfecdis.0c00246},
pmid = {32510928},
issn = {2373-8227},
abstract = {Pseudomonas aeruginosa is the main contributor to the morbidity and mortality of cystic fibrosis (CF) patients. Chronic respiratory infections are rarely eradicated due to protection from CF mucus and the biofilm matrix. The composition of the biofilm matrix determines its viscoelastic properties and affects antibiotic efficacy. Nitric oxide (NO) can both disrupt the physical structure of the biofilm and eradicate interior colonies. The effects of a CF-like growth environment on P. aeruginosa biofilm susceptibility to NO were investigated using parallel plate macrorheology and particle tracking microrheology. Biofilms grown in the presence of mucins and DNA contained greater concentrations of DNA in the matrix and exhibited concomitantly larger viscoelastic moduli compared to those grown in tryptic soy broth. Greater viscoelastic moduli correlated with increased tolerance to tobramycin and colistin. Remarkably, NO-releasing cyclodextrins eradicated all biofilms at the same concentration. The capacity of NO-releasing cyclodextrins to eradicate P. aeruginosa biofilms irrespective of matrix composition suggests that NO-based therapies may be superior antibiofilm treatments compared to conventional antibiotics.},
}
@article {pmid32510869,
year = {2020},
author = {Liu, Z and Hong, CJ and Yang, Y and Dai, L and Ho, CL},
title = {Advances in Bacterial Biofilm Management for Maintaining Microbiome Homeostasis.},
journal = {Biotechnology journal},
volume = {},
number = {},
pages = {e1900320},
doi = {10.1002/biot.201900320},
pmid = {32510869},
issn = {1860-7314},
abstract = {Certain microbial biofilm in the human-microbiota community can negatively impact the host microbiome. This gives rise to various methods to prevent the formation of biofilms or to facilitate biofilm dispersal from surfaces and tissues in the host. Despite all these efforts, these persistent microbial biofilms on surfaces and in the host tissue can result in health problems to the host and its microbiome. It is the adaptive behavior of microbes within the biofilm that confers these tenacious microbes the resistance to harsh environments, antibiotic treatments, and the ability to evade the host immune system. In this review, we will discuss the approaches to combat microbial biofilm in the last decade. We first discuss the biochemical pathway regulating biofilm formation, followed by the discussion of the three approaches to combat biofilm formation: physical, chemical, and biological approaches. The advances in these approaches have given rise to methods of effectively dispersing the microbial biofilm and preventing the adherence of these microbial communities altogether. As there are numerous approaches to target biofilm, in this review we seek to provide insights on how these approaches have been used to modulate the host-microbiome by looking at the individual strengths and weaknesses. This article is protected by copyright. All rights reserved.},
}
@article {pmid32510398,
year = {2020},
author = {Ng, JCY and Chiu, JMY},
title = {Changes in biofilm bacterial communities in response to combined effects of hypoxia, ocean acidification and nutrients from aquaculture activity in Three Fathoms Cove.},
journal = {Marine pollution bulletin},
volume = {156},
number = {},
pages = {111256},
doi = {10.1016/j.marpolbul.2020.111256},
pmid = {32510398},
issn = {1879-3363},
abstract = {Anthropogenic nutrient enrichment results in hypoxia, ocean acidification and elevated nutrients (HOAN) in coastal environments throughout the world. Here, we examined the composition of biofilm bacterial communities from a nutrient-excessive fish farm with low dissolved oxygen (DO) and pH levels using 16S rRNA gene sequencing. HOAN was accompanied by higher bacterial diversity and richness, and resulted in an altered community composition than the control site. HOAN resulted in more Flavobacteriales, Rhizobiales, Epsilonproteobacteria and Vibrionales, but less Oceanospirillales and Alteromonadales. Photobacterium sp. and Vibrio sp. were mostly found to be exclusive to HOAN conditions, suggesting that HOAN could possibly proliferate the presence of these potential pathogens. Our study suggests the complexity of bacterial communities to hypoxia and acidification in response to increased nutrient loads, along with identities of nutrient, oxygen and pH-susceptible bacterial groups that are most likely affected under this ocean trend.},
}
@article {pmid32509022,
year = {2020},
author = {Li, T and Wang, G and Yin, P and Li, Z and Zhang, L and Tang, P},
title = {Adaptive expression of biofilm regulators and adhesion factors of Staphylococcus aureus during acute wound infection under the treatment of negative pressure wound therapy in vivo.},
journal = {Experimental and therapeutic medicine},
volume = {20},
number = {1},
pages = {512-520},
pmid = {32509022},
issn = {1792-0981},
abstract = {Negative pressure wound therapy (NPWT) is gaining acceptance as a physical therapy for a wide variety of infected wounds. To gain insight into the response of bacteria to NPWT in vivo, the adaptive expression of biofilm regulators and adhesion factors of Staphylococcus aureus (S. aureus), the most frequently isolated pathogen in the clinic, during acute wound infection was investigated. A 3 cm full-thickness dermal wound was created on each side of a rabbit back and inoculated with green fluorescent protein-labeled S. aureus. NPWT was initiated at 6 h post inoculation, with the wound on the contralateral side as the untreated self-control. The wounds were subjected to a 28 day observation period. Histological analysis, laser scanning confocal microscopy and scanning electron microscopy revealed a transition of S. aureus to a free-living phenotype in tissues treated with NPWT, compared with microcolonies in untreated wounds. Viable bacteria counts showed a modest reduction in the bioburden of NPWT group on day 8 (P<0.001), with ~1x106 colony-forming units/g tissue. Transcript analysis of biofilm- and colonization-related genes were investigated using reverse transcription-quantitative PCR on postoperative days 1, 2, 4 and 8. The poly-beta-1,6-N-acetyl-D-glucosamine synthase locus and holin-like protein CidA/antiholin-like protein LrgA network were less active in the NPWT group compared with the untreated control group. Accordingly, the expression profile switched to an elevated expression of the adhesive factors UDP-phosphate N-acetylglucosaminyl 1-phosphate transferase (at days 0-4) and fibronectin-binding protein A and iron-regulated surface determinant protein A at >4 days during both stages of colonization. Meanwhile, low expression levels of the effector molecule (RNAIII) of the accessory gene regulator type I (agr) system was detected in NPWT group, suggesting that the bacterial density in NPWT-treated wounds was under the threshold for agr activation, thus not leading to an active and invasive infection. The wounds treated by NPWT healed completely on day 28, compared with an average of an 8.11% defect area in the control group (P<0.001). The results of the current study indicated that S. aureus responds to NPWT by regulating gene expression, manifesting a decrease in biofilm formation and an increase in bacterial colonization in vivo, which potentially benefits the wound repair and healing process.},
}
@article {pmid32508783,
year = {2020},
author = {Wang, Z and Shen, Y and Haapasalo, M},
title = {Dynamics of Dissolution, Killing, and Inhibition of Dental Plaque Biofilm.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {964},
pmid = {32508783},
issn = {1664-302X},
abstract = {The present study aims to establish a standardized model that makes it possible to evaluate the dynamic dissolution of biofilm, killing of biofilm microbes and inhibition of growth of biofilm by disinfecting solutions. Biofilm was grown from dental plaque bacteria on collagen-coated hydroxyapatite (HA) disks for 3 days or 3 weeks under anaerobic conditions. Biofilms were stained with the LIVE/DEAD viability stain and subjected to sterile water, 2% sodium hypochlorite (NaOCl), 6% NaOCl, or 2% chlorhexidine (CHX) for 32 min. Dynamic change in fluorescence on bacterial cells and extracellular polymeric substance (EPS) during the exposure was analyzed using Alexa Fluor 647-labeled dextran conjugate and a live-cell imaging confocal laser scanning microscopy (LC-CLSM). The biofilm structures after treatments were visualized by scanning electron microscopy (SEM). The treated biofilms on HA disks were collected and subjected to colony forming unit (CFU) counting. Another set of sterile HA disks were coated with CHX prior to the monitoring of plaque biofilm growth for 12 h. The LC-CLSM results showed that NaOCl dissolved biofilm effectively, more so at a higher concentration and longer exposure time. Six percent NaOCl was the most effective at dissolving and killing bacteria (e.g., 99% bacterial reduction in 3-day-old biofilm and 95% bacterial reduction in 3-week-old biofilm in 32 min) followed by 2% NaOCl and CHX. Sodium hypochlorite dissolved over 99.9% of the EPS whereas CHX only slightly reduced the EPS biovolume in 32 min. CFU results indicated that the dispersed biofilm bacteria are more resistant than planktonic bacteria to disinfectants. SEM showed the disruption of biofilm after exposures to CHX and NaOCl. The use of 2% CHX and sterile water did not result in biofilm dissolution. However, prior exposure of the HA disks to 2 and 0.2% CHX for 3 min prevented biofilm from growing on the HA disk surfaces for at least 12 h. This new platform has the potential to aid in a better understanding of the antibiofilm properties of oral disinfectants.},
}
@article {pmid32508761,
year = {2020},
author = {Li, W and Wang, JJ and Qian, H and Tan, L and Zhang, Z and Liu, H and Pan, Y and Zhao, Y},
title = {Insights Into the Role of Extracellular DNA and Extracellular Proteins in Biofilm Formation of Vibrio parahaemolyticus.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {813},
pmid = {32508761},
issn = {1664-302X},
abstract = {The extracellular polymeric substances (EPS) construct the three-dimensional (3-D) structure of biofilms, but their respective roles are still not clear. Therefore, this study aimed to illuminate the role of key chemical components [extracellular DNA (eDNA), extracellular proteins, and carbohydrates] of EPS in biofilm formation of Vibrio parahaemolyticus. The correlations between each key chemical component and biofilm formation were first determined, showing that the biofilm formation of V. parahaemolyticus was strongly positively correlated with both eDNA and protein content (P < 0.01), but not with carbohydrates. Subsequently, individual DNase I or protease K treatment markedly reduced the initial adhesion and structural stability of the formed biofilms by hydrolyzing the eDNA or extracellular proteins, but did not induce significant dispersion of mature biofilms. However, the combination of DNase I and protease K treatment induced the obvious dispersion of the mature biofilms through the concurrent destruction of eDNA and extracellular proteins. The analysis at a structural level showed that the collapse of biofilms was mainly attributed to the great damage of the loop configuration of eDNA and the secondary structure of proteins caused by the enzyme treatment. Therefore, this study provides a deep understanding of the role of key chemical components of EPS in biofilm development of V. parahaemolyticus, which may give a new strategy to develop environmentally friendly methods to eradicate the biofilms in food industry.},
}
@article {pmid32507630,
year = {2020},
author = {López, ALR and Lee, MR and Ortiz, BJ and Gastfriend, BD and Whitehead, R and Lynn, DM and Palecek, SP},
title = {Corrigendum to &quot;Preventing S. aureus biofilm formation on titanium surfaces by the release of antimicrobial β-peptides from polyelectrolyte multilayers&quot; Acta Biomaterialia 2019, 93, 50-62.},
journal = {Acta biomaterialia},
volume = {111},
number = {},
pages = {429},
doi = {10.1016/j.actbio.2020.05.003},
pmid = {32507630},
issn = {1878-7568},
support = {R33 AI127442/AI/NIAID NIH HHS/United States ; },
}
@article {pmid32506835,
year = {2020},
author = {Panchatcharam, BS and Cooksley, CM and Ramezanpour, M and Vediappan, RS and Bassiouni, A and Wormald, PJ and Psaltis, AJ and Vreugde, S},
title = {Staphylococcus aureus biofilm exoproteins are cytotoxic to human nasal epithelial barrier in chronic rhinosinusitis.},
journal = {International forum of allergy &amp; rhinology},
volume = {10},
number = {7},
pages = {871-883},
doi = {10.1002/alr.22566},
pmid = {32506835},
issn = {2042-6984},
abstract = {BACKGROUND: Chronic rhinosinusitis patients (CRS) suffer from chronic inflammation of the sinus mucosa associated with chronic relapsing infections. Mucosal biofilms, associated with Staphylococcus aureus, have been implicated as a cause. We compared the effect of exoproteins secreted from clinical isolates of S aureus from CRS patients in planktonic and biofilm form on the nasal epithelial barrier.<br><br>METHODS: Clinical S aureus isolates from 39 CRS patients were grown in planktonic and biofilm forms and their exoproteins concentrated. These were applied to primary human nasal epithelial cells grown at the air-liquid interface. Transepithelial electrical resistance, permeability of flourescein isothiocyanate-dextrans, and cytotoxicity were measured. Structure and expression of tight junctions zona occludens-1, and claudin-1 proteins were assessed by electron microscopy and immunofluorescence. The Wilcoxon signed rank test was used for statistical analyses.<br><br>RESULTS: S aureus biofilm exoproteins showed dose- and time-dependent reduction of transepithelial electrical resistance, increased cell toxicity, and increased permeability (p < 0.001) compared with equal concentrations of planktonic cultures. Discontinuity in zona occludens-1 and claudin-1 immunofluorescence was confirmed as disrupted tight junctions on electron microscopy.<br><br>CONCLUSION: S aureus biofilm exoproteins disrupt the mucosal barrier structure in a time- and dose-dependent manner and are toxic. Damage to the mucosal barrier by S aureus biofilm exoproteins may play a major role in CRS etiopathogenesis.},
}
@article {pmid32505890,
year = {2020},
author = {Kragh, ML and Muchaamba, F and Tasara, T and Truelstrup Hansen, L},
title = {Cold-shock proteins affect desiccation tolerance, biofilm formation and motility in Listeria monocytogenes.},
journal = {International journal of food microbiology},
volume = {329},
number = {},
pages = {108662},
doi = {10.1016/j.ijfoodmicro.2020.108662},
pmid = {32505890},
issn = {1879-3460},
abstract = {Listeria monocytogenes is a foodborne pathogen whose biofilm formation and desiccation tolerance may contribute to its survival in the food industry. L. monocytogenes possesses three cold-shock domain family proteins (CspA, CspB and CspD) known to be essential for adaptation against various food-relevant stress conditions including cold growth. The role of Csps in desiccation tolerance and biofilm formation was investigated in csp mutants as well as twenty-one other wild-type (WT) strains. Mutants with a single (ΔcspA) or multiple (ΔcspAB, ΔcspAD and ΔcspABD) deletions of csp genes, in a desiccation sensitive WT background (L. monocytogenes EGD-e) were immotile and exhibited an elevated desiccation tolerance compared to the parent strain. However, deletion of cspA in the more desiccation resistant food and outbreak related L. monocytogenes strains 568 and 08-5578 had no impact on desiccation tolerance although compared to the parent strains the mutants were also immotile. A correlation between lower motility and higher desiccation tolerance was observed among the 20 WT strains (Spearman rank correlation, rs = -0.56, p = 0.01), although exceptions occurred indicating that multiple factors influence the diverse desiccation tolerance among L. monocytogenes strains. Expression of cspA was upregulated in WT EGD-e, 568 and 08-5578 strains after desiccation for seven days, while the 568 and 08-5578 ΔcspA mutants expressed elevated levels of cspD and cspB (>30 fold higher) compared to their WTs. This indicates that upregulation of the other csps compensates for the deleted cspA gene. Although biofilm formation was improved in all EGDe csp mutants relative to the WT strain, the opposite was observed for 568 and 08-5578 WT strains and their cspA deletion mutants. Only motile strains formed biofilm in the peg lid assay but a significant negative correlation (rs = -0.60, p = 0.01) was seen between higher motility and higher biofilm formation of WT strains. In conclusion, the survival of L. monocytogenes strains in the food processing environment may depend on the control of motility, which is a necessity for biofilm formation but disadvantageous for desiccation survival.},
}
@article {pmid32505537,
year = {2020},
author = {Porter, GC and Tompkins, GR and Schwass, DR and Li, KC and Waddell, JN and Meledandri, CJ},
title = {Anti-biofilm activity of silver nanoparticle-containing glass ionomer cements.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.dental.2020.05.001},
pmid = {32505537},
issn = {1879-0097},
abstract = {OBJECTIVE: To develop a silver nanoparticle (AgNP) formulation for incorporation into glass ionomer cements (GICs) which minimises biofilm growth on restoration surfaces.<br><br>METHODS: GICs, Fuji IX, Ketac Molar, and Riva Selfcure were modified with 6, 10 and 24 μg per GIC capsule of α-lipoic acid-capped AgNPs. Monoculture biofilms of Streptococcus mutans were cultured (72 h) on GIC specimens (n = 3) and biofilm accumulation was quantified using a viability stain with confocal laser scanning microscopy. Compression strength and flexural strength (CS &amp; FS) were measured according to ISO 9917-1:2007 (n = 8, n = 25). GIC colour was measured at 0, 1, and 14 days following AgNP incorporation using a digital spectrophotometer. Silver release from AgNP-modified GIC specimens was monitored at 1, 3, 7 and 14 days using inductively coupled plasma-mass spectrometry.<br><br>RESULTS: AgNP-modified Fuji IX demonstrated the greatest reduction in biofilm accumulation, with 10 μg Ag/capsule inhibiting biofilm formation by 99%. Ketac Molar and Riva Selfcure required 24 μg Ag/capsule to achieve 78% biofilm reduction. AgNP-modified GICs demonstrated significantly higher CS and FS than sintered silver-containing GICs, and possessed equivalent or higher strength values when compared to unmodified GICs. The colour shades of AgNP-modified GICs were more comparable to VITA shades of non-modified GICs than were sintered silver-containing GICs. The silver (≥99.6%) remained within the GIC for at least two weeks following incorporation.<br><br>SIGNIFICANCE: AgNP-modified GICs exhibited significant antibiofilm activity and retained mechanical properties equivalent or superior to non-modified GICs. AgNP-modified GICs could reduce bacterial colonisation on and around restorations thereby reducing restoration failure caused by secondary caries.},
}
@article {pmid32504487,
year = {2020},
author = {Wu, J and Yang, Q and Jiang, X and Fan, Y and Zhang, Y and Huang, R},
title = {Oxyresveratrol promotes biofilm formation, cell attachment and aggregation of Streptococcus gordonii in the presence of sucrose.},
journal = {FEMS microbiology letters},
volume = {367},
number = {12},
pages = {},
doi = {10.1093/femsle/fnaa090},
pmid = {32504487},
issn = {1574-6968},
abstract = {Streptococcus gordonii is a commensal colonizer of oral cavity that initiates the formation of dental plaque. Oxyresveratrol is a natural purification from plants with antibacterial effects on various oral bacteria including Streptococcus mutans. The aim of this study was to investigate the effects of oxyresveratrol on S. gordonii. The basic viability, biofilm formation and cell aggregation of S. gordonii treated with oxyresveratrol were investigated. Oxyresveratrol dose-dependently inhibited the growth of S. gordonii in the absence of sucrose. However, in the presence of sucrose, it promoted biofilm formation under MIC. Both the biofilm formation and extracellular polysaccharides synthesis reached the maximum level at ½ MIC (250 μg/mL) oxyresveratrol. The gene expressions of abpA, abpB, scaA, gtfG, hsa, cshA, cshB, ccpA, srtA and sspB were upregulated when treated with 62.5 and 125 μg/mL oxyresveratrol. A total eight of the ten genes were significantly upregulated at 250 μg/mL oxyresveratrol except abpB and sspB, which were downregulated at 250 μg/mL without significance. In conclusion, oxyresveratrol has dual-effects on S. gordonii. Considering its specific biofilm suppressive effect on S. mutans, it might be a candidate for bacterial interspecies modulator applied in caries prevention.},
}
@article {pmid32503907,
year = {2020},
author = {Guan, C and Che, F and Zhou, H and Li, Y and Li, Y and Chu, J},
title = {Effect of rubusoside, a natural sucrose substitute, on the cariogenic potential and virulence gene expression of Streptococcus mutans biofilm in vitro.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.01012-20},
pmid = {32503907},
issn = {1098-5336},
abstract = {Dental caries is a biofilm-mediated disease with Streptococcus mutans as the main pathogenic microorganism, and its incidence is closely related to sucrose. Rubusoside is a natural non-nutritive sweetener isolated from Rubus suavissimu S.Lee. This study was designed to determine the effect of the sucrose substitute on cariogenic properties and virulence gene expression of S. mutans biofilms. S. mutans was exposed to: BHI medium (as a control), BHI+1% sucrose, BHI+1% rubusoside, and BHI +1% xylitol. The growth curve of biofilm was monitored with crystal violet staining and pH was measured every 24 h. After 5 days, the biofilms formed on the glass coverslips were recovered to determine the biomass (dry weight and total soluble proteins), colony-forming units, and intra- and extracellular polysaccharides. Biofilm structural imaging was observed using a scanning electron microscope (SEM). The virulence gene expression (gtfB, gtfC, gtfD, ftf, spaP, gbpB, ldh, atpF, vicR, and comD) was determined by rt-qPCR. Compared to growth in sucrose, xylitol and control, growth in rubusoside resulted in a lower acid production, while also reducing the biofilm accumulation, bacterial viability, and even reducing the production of extracellular polysaccharides. And less biofilm formation and extracellular matrix was observed through SEM in rubusoside than sucrose and xylitol. From the perspective of virulence genes, rubusoside and xylitol significantly inhibited expression of virulence genes compared with sucrose, among which, down-regulation of the gtfB, gtfC, gbpB, ldh, and comD was found in rubusoside than xylitol. Therefore, rubusoside appears to be less potential cariogenicity than sucrose and xylitol, and may become an effective sucrose substitute for caries prevention. Further studies need to deepen these findings.Importance Dental caries, as a major public health challenge, places a heavy biological, social and financial burden on individuals and health care systems. To palliate the deleterious effect of sucrose on the virulence factors of S. mutans, massive commercial products have oriented towards developing sucrose substitutes. Rubusoside, a natural sucrose substitute, is a plant extract with high sweetness. Although some studies have shown that rubusoside do not produce acids and inhibit the growth of S. mutans, little attention has been paid to dental biofilm and underlying mechanisms. Our study focuses on the effect of rubusoside on formation and structure of biofilm, and expression of virulence genes. Results confirms that rubusoside can inhibit accumulation, bacterial viability, polysaccharide production of biofilm, and inhibit related gene expression. These results provide further insight into the cariogenicity of S. mutans biofilm, and demonstrate a new perspective for studying the impact of sucrose substitutes on caries.},
}
@article {pmid32503624,
year = {2020},
author = {Liu, Y and Hannig, M},
title = {Vinegar inhibits the formation of oral biofilm in situ.},
journal = {BMC oral health},
volume = {20},
number = {1},
pages = {167},
pmid = {32503624},
issn = {1472-6831},
support = {SFB 1027//German Research Foundation, DFG, SFB 1027/ ; },
abstract = {BACKGROUND: Vinegar has been recognized as an effective antimicrobial agent for long. This study intended to elucidate the effect of commercially available vinegar on in situ pellicle formation and existing 24-h biofilms.<br><br>METHODS: In situ biofilm formation took place on bovine enamel slabs mounted in individual splints and exposed intraorally over 3 min and 24 h, respectively. After 5 s rinsing with vinegar, all samples were analyzed via fluorescence microscopy (FM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, salivary samples were collected and analyzed via FM. Samples with water rinsing served as controls.<br><br>RESULTS: Vinegar caused destruction of the pellicle. Compared to the control group, vinegar rinsing reduced the outer globular layer of the pellicle (p < 0.001), and resulted in formation of subsurface pellicle. Also, vinegar rinsing could reduce bacterial viability and disrupt the 24-h biofilm. Total bacteria amount of saliva samples decreased remarkably (p < 0.001) after vinegar rinsing within 30 min. Reduction of bacterial viability was observed even 120 min after vinegar rinsing in both biofilm and saliva sample (p < 0.001).<br><br>CONCLUSION: This in situ study reveals that rinsing with vinegar for only 5 s alters the pellicle layer resulting in subsurface pellicle formation. Furthermore, vinegar rinsing will destruct mature (24-h) biofilms, and significantly reduce the viability of planktonic microbes in saliva, thereby decreasing biofilm formation.},
}
@article {pmid32503535,
year = {2020},
author = {Sun, Y and Wen, S and Zhao, L and Xia, Q and Pan, Y and Liu, H and Wei, C and Chen, H and Ge, J and Wang, H},
title = {Association among biofilm formation, virulence gene expression, and antibiotic resistance in Proteus mirabilis isolates from diarrhetic animals in Northeast China.},
journal = {BMC veterinary research},
volume = {16},
number = {1},
pages = {176},
pmid = {32503535},
issn = {1746-6148},
support = {No. 17XG10//the &quot;Academic Backbone&quot; Project of Northeast Agricultural University/ ; 31672532//National Natural Science Foundation of China/ ; 201910224139//SIPT Program/ ; },
abstract = {BACKGROUND: The aim of this study was to investigate the association among biofilm formation, virulence gene expression, and antibiotic resistance in P. mirabilis isolates collected from diarrhetic animals (n = 176) in northeast China between September 2014 and October 2016.<br><br>RESULTS: Approximately 92.05% of the isolates were biofilm producers, whereas 7.95% of the isolates were non-producers. The prevalence of virulence genes in the biofilm producer group was significantly higher than that in the non-producer group. Biofilm production was significantly associated with the expression of ureC, zapA, rsmA, hmpA, mrpA, atfA, and pmfA (P < 0.05). The results of drug susceptibility tests revealed that approximately 76.7% of the isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR). Biofilm production was significantly associated with resistance to doxycycline, tetracycline, sulfamethoxazole, kanamycin, and cephalothin (P < 0.05). Although the pathogenicity of the biofilm producers was stronger than that of the non-producers, the biofilm-forming ability of the isolates was not significantly associated with morbidity and mortality in mice (P > 0.05).<br><br>CONCLUSION: Our findings suggested that a high level of multidrug resistance in P. mirabilis isolates obtained from diarrhetic animals in northeast China. The results of this study indicated that the positive rates of the genes expressed by biofilm-producing P. mirabilis isolates were significantly higher than those expressed by non-producing isolates.},
}
@article {pmid32502632,
year = {2020},
author = {Vijayakumar, K and Bharathidasan, V and Manigandan, V and Jeyapragash, D},
title = {Quebrachitol inhibits biofilm formation and virulence production against methicillin-resistant Staphylococcus aureus.},
journal = {Microbial pathogenesis},
volume = {149},
number = {},
pages = {104286},
doi = {10.1016/j.micpath.2020.104286},
pmid = {32502632},
issn = {1096-1208},
abstract = {The present study evaluated the quebrachitol (QBC) antibiofilm and antivirulence potential against methicillin-resistant Staphylococcus aureus (MRSA). QBC inhibited MRSA biofilm formation at concentration dependent manner without affecting the bacterial growth. Then, QBC biofilm efficacy was confirmed with light and confocal laser scanning microscopy analysis. QBC treatment significantly inhibited the biofilm formation on stainless steel, titanium and silicone surfaces. Besides, QBC treatment significantly reduced the MRSA virulence productions such as lipase and hemolysis. Moreover, it reduced MRSA survival rate in the presence of hydrogen peroxide. QBC treatment inhibited the MRSA adherence on hydrophobic, hydrophilic, collagen coating and fibrinogen coating surfaces. As well as it significantly reduced the autolysin and bacterial aggregation progress. The real-time PCR analysis revealed the ability of QBC downregulated the virulence genes expression including global regulator sarA, agr and polysaccharide intracellular adhesion (PIA) encode ica. The cumulative results of the present study suggest that QBC as a potential agent to combat against MRSA pathogenesis.},
}
@article {pmid32502284,
year = {2020},
author = {Pereira, TC and Dijkstra, RJB and Petridis, X and van der Meer, WJ and Sharma, P and de Andrade, FB and van der Sluis, LWM},
title = {The influence of time and irrigant refreshment on biofilm removal from lateral morphological features of simulated root canals.},
journal = {International endodontic journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/iej.13342},
pmid = {32502284},
issn = {1365-2591},
abstract = {AIM: To evaluate the effect of irrigant refreshment and exposure time of a 2% sodium hypochlorite solution (NaOCl) on biofilm removal from simulated lateral root canal spaces using two different flow rates.<br><br>METHODOLOGY: A dual-species biofilm was formed by a Constant Depth Film Fermentor (CDFF) for 96 hours in plug inserts with anatomical features resembling an isthmus or lateral canal like structures. The inserts where placed in a root canal model facing the main canal. NaOCl 2% and demineralized water (control group) were used as irrigant solutions. Both substances were applied at a flow rate of 0.05 and 0.1 mL/second. The samples were divided in three groups with zero, one or two refreshments in a total exposure time of 15 minutes. A three-way Analysis of Variance (ANOVA) was performed to investigate the interaction among the independent variables and the effect of consecutive irrigant refreshment on percentage of biofilm removal. A Tukey post hoc test was used to evaluate the effect of each independent variable on percentage biofilm removal in the absence of statistically significant interactions.<br><br>RESULTS: For the lateral canal, NaOCl removed significantly more biofilm irrespective of the number of refreshments and exposure time (P = 0.005). There was no significant effect in biofilm removal between the consecutive irrigant refreshments measured in the same biofilm. For the isthmus, NaOCl removed significantly more biofilm irrespective of the number of refreshments and exposure time; both NaOCl and a high flow rate removed significant more biofilm when the exposure time was analyzed (P = 0.018 and P = 0.029, respectively). Evaluating the effect of consecutive irrigant refreshment on the same biofilm, 2% NaOCl, 0.1 mL/s flow rate and one or two refreshments removed significant more biofilm (P = 0.04, P = 0.034 and P = 0.003, P <0.001, respectively).<br><br>CONCLUSIONS: In this model, refreshment did not improve biofilm removal from simulated lateral root canal spaces. NaOCl removed more biofilm from the lateral canal and isthmus-like structure. A higher flow rate removed significantly more biofilm from the isthmus like structure. There was always remaining biofilm left after the irrigation procedures.},
}
@article {pmid32500253,
year = {2020},
author = {Khosravi, M and Mirzaie, A and Kashtali, AB and Noorbazargan, H},
title = {Antibacterial, anti-efflux, anti-biofilm, anti-slime (exopolysaccharide) production and urease inhibitory efficacies of novel synthesized gold nanoparticles coated Anthemis atropatana extract against multidrug- resistant Klebsiella pneumoniae strains.},
journal = {Archives of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00203-020-01930-y},
pmid = {32500253},
issn = {1432-072X},
abstract = {In this study, the antibacterial, anti-efflux, anti-biofilm, anti-slime (exopolysaccharide) production and urease inhibitory efficacies of green synthesized gold nanoparticles (AuNPs) coated Anthemis atropatana extract against multidrug- resistant (MDR) Klebsiella pneumoniae strains were evaluated. The green synthesized AuNPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffractometer (XRD), particle size distribution, zeta potential and Fourier-transform infrared spectroscopy (FTIR). Then, antibacterial, anti-slime (exopolysaccharide) production, anti-biofilm and anti-efflux activities of AuNPs were investigated using micro-dilation, Congored agar, microtiter plate and MIC of ethidium bromide methods, respectively. Subsequently, the expression of mrkA, wzm and acrB genes was evaluated using quantitative Real-Time PCR (qRT-PCR). The synthesized AuNPs exhibited antibacterial activity against MDR strains of K. pneumoniae (minimum inhibitory concentration (MIC) of 6.25-50 µg/ml), as well as showed significant anti-slime (exopolysaccharide) production, anti-biofilm and anti-efflux activities against MDR strains. AuNPs showed significant inhibition against jack-bean urease and down-regulated the expression of mrkA, wzm and acrB genes. Moreover, the in vitro cytotoxic activity confirmed by MTT assay on the HEK-293 normal cell line showed negligible cytotoxicity. Thus, the present study suggests the potential use of AuNPs in the development of novel therapeutics for the prevention of biofilm-associated K. pneumoniae infections.},
}
@article {pmid32498595,
year = {2020},
author = {Mirzaei, B and Babaei, R and Valinejad, S},
title = {Staphylococcal Vaccine Antigens related to biofilm formation.},
journal = {Human vaccines &amp; immunotherapeutics},
volume = {},
number = {},
pages = {1-11},
doi = {10.1080/21645515.2020.1767449},
pmid = {32498595},
issn = {2164-554X},
abstract = {The number and frequency of multidrug-resistant (MDR) strains as a frequent cause of nosocomial infections have increased, especially for Methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis, in part due to device-related infections. The transition to antibiotic-resistance in related bacterial genes and the capability for immune escape have increased the sustainability of biofilms produced by these bacteria. The formation and changes in biofilms have been suggested as a target to prevent or treat staphylococcal infections. Thus, this study reviews the development of candidate staphylococcal vaccines by database searching, and evaluates the immunogenicity and efficacy profiles of bacterial components involved in biofilms. The literature suggests that using common staphylococcal vaccine antigens and multivalent vaccines should further enhance vaccine efficacy.},
}
@article {pmid32498472,
year = {2020},
author = {Ni, P and Wang, L and Deng, B and Jiu, S and Ma, C and Zhang, C and Almeida, A and Wang, D and Xu, W and Wang, S},
title = {Combined Application of Bacteriophages and Carvacrol in the Control of Pseudomonas syringae pv. actinidiae Planktonic and Biofilm Forms.},
journal = {Microorganisms},
volume = {8},
number = {6},
pages = {},
doi = {10.3390/microorganisms8060837},
pmid = {32498472},
issn = {2076-2607},
support = {MH235//Shanghai Minhang Science and Technology Commission/ ; },
abstract = {Pseudomonas syringae pv. actinidiae (Psa) is the causative agent of the bacterial canker of kiwifruit (Actinidia spp.). Phage therapy has been suggested as a viable alternative approach to controlling this disease, but its efficacy is limited by the emergence of phage-resistant mutants. Carvacrol is an essential oil that may be useful for the control of Psa. Combination therapies can be used to overcome resistance development. Here, the combination of phages (single phage suspensions of phages PN05 and PN09, and a cocktail of both phages) and carvacrol was investigated in controlling Psa planktonic and biofilm forms in vitro. The phage therapy alone (with phages PN05 and PN09), and the carvacrol alone (minimum inhibitory concentration 2.0 mg/mL), inhibited Psa growth, but the combined effect of both therapies was more effective. The phages alone effectively inhibited Psa growth for 24 h, but Psa regrowth was observed after this time. The carvacrol (2.0 mg/mL) alone prevented the biofilm formation for 48 h, but did not destroy the pre-formed biofilms. The combined treatment, phages and carvacrol (2.0 mg/mL), showed a higher efficacy, preventing Psa regrowth for more than 40 h. In conclusion, the combined treatment with phages and carvacrol may be a promising, environment-friendly and cost-effective approach to controlling Psa in the kiwifruit industry.},
}
@article {pmid32497775,
year = {2020},
author = {Pourhajibagher, M and Miri-Moosavi, RS and Chiniforush, N and Safaraei, Y and Kia, SA and Lalegani, MR and Bazarjani, F and Bahador, A},
title = {Anti-biofilm activity of Chlorella-mediated light activated disinfection: Ex vivo inhibition of intracanal mature Enterococcus faecalis biofilms via application of natural product.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {101853},
doi = {10.1016/j.pdpdt.2020.101853},
pmid = {32497775},
issn = {1873-1597},
abstract = {BACKGROUND: This study aimed to evaluate the effects of light-activated disinfection (LAD) as a strategy for optimizing root canal disinfection using Chlorella (Chlo) as a natural photosensitizer against Enterococcus faecalis biofilms ex vivo.<br><br>MATERIALS AND METHODS: The physical and chemical stability and absorption spectra of Chlo were determined. The mature microbial biofilm of E. faecalis was formed in root canals of 70 freshly extracted single-rooted premolars. After determining the minimum inhibitory concentration (MIC) of Chlo using the agar dilution testing, E. faecalis biofilms were exposed in the following groups (n = 10): 1- Chlo at a concentration of 2 × MIC, 1- Chlo at a concentration of 4 × MIC, 3- Diode laser, 4- 2 × MIC dose of Chlo-mediated LAD, 5- 4 × MIC dose of Chlo-mediated LAD, 6- 0.2% chlorohexidine (CHX), and 7- control group (E. faecalis biofilms without exposure to any photosensitizer and light source). The quantitative and qualitative evaluations of E. faecalis biofilms were done using counts of colony forming units (CFUs) and scanning electron microscope (SEM) and fluorescence microscope analysis, respectively.<br><br>RESULTS: According to the results, the MIC of Chlo was 125 μg/mL, which inhibited the growth of E. faecalis. To evaluate the anti-biofilm effects of Chlo, the 2× and 4 × MICs of Chlo (250 and 500 μg/mL, respectively) were used in the current study. The 4 × MIC dose (500 μg/mL) of Chlo-mediated LAD was significantly more effective compared to other groups (P < 0.05), while the lowest percentage of dead cells was detected in the diode laser irradiation group. In addition, there was no significant difference in the log10 CFU of E. faecalis between the biofilm treated with 500 μg/mL Chlo-mediated LAD (1.27 ± 0.05) versus 0.2% CHX (1.10 ± 0.06) (P < 0.05). As Moreover, SEM and fluorescence microscope images of the microbial biofilms showed that the highest percentage of dead bacteria was found in the 500 μg/mL Chlo-mediated LAD group.<br><br>CONCLUSIONS: The results of this study suggest that Chlo-mediated LAD can be used as an adjuvant therapy to eliminate the E. faecalis biofilms in the root canal system.},
}
@article {pmid32496982,
year = {2020},
author = {Thaarup, IC and Bjarnsholt, T},
title = {Current in vitro biofilm-infected chronic wound models for developing new treatment possibilities.},
journal = {Advances in wound care},
volume = {},
number = {},
pages = {},
doi = {10.1089/wound.2020.1176},
pmid = {32496982},
issn = {2162-1918},
abstract = {SIGNIFICANCE: The prevalence of chronic wounds is increasing worldwide. The most recent estimates suggest that up to 2% of the population in the industrialized countries are affected.1 Recent Advances: During the past few decades, bacterial biofilms have been elucidated as one of the primary reasons why chronic wounds fail to heal.2,3 Critical Issues: There is a lack of direct causation and evidence of the role that biofilms play in persistent wounds, which complicates research on new treatment options, since it is still unknown which factors dominate. For this reason, several different in vitro wound models have been created, that mimic the biofilm infections observed in chronic wounds and other chronic infections. These different models are, amongst other purposes, used to test a variety of wound care products. However, chronic wounds are highly complex, and several different factors must be taken into consideration along with the infection, including physiochemical and human-supplemented factors. Furthermore, the limitations of using in vitro models, such as the lack of a responsive immune system should always be given due consideration.<br><br>FUTURE DIRECTIONS: Present understandings of all the elements and interactions that take place within chronic wounds are incomplete. As our insight of in vivo chronic wounds continues to expand, so too must the in vitro models used to mimic these infections evolve and adapt to new knowledge.},
}
@article {pmid32496187,
year = {2020},
author = {Pezzoni, M and Pizarro, RA and Costa, CS},
title = {Role of quorum sensing in UVA-induced biofilm formation in Pseudomonas aeruginosa.},
journal = {Microbiology (Reading, England)},
volume = {},
number = {},
pages = {},
doi = {10.1099/mic.0.000932},
pmid = {32496187},
issn = {1465-2080},
abstract = {Pseudomonas aeruginosa, a versatile bacterium present in terrestrial and aquatic environments and a relevant opportunistic human pathogen, is largely known for the production of robust biofilms. The unique properties of these structures complicate biofilm eradication, because they make the biofilms very resistant to diverse antibacterial agents. Biofilm development and establishment is a complex process regulated by multiple regulatory genetic systems, among them is quorum sensing (QS), a mechanism employed by bacteria to regulate gene transcription in response to population density. In addition, environmental factors such as UVA radiation (400-315 nm) have been linked to biofilm formation. In this work, we further investigate the mechanism underlying the induction of biofilm formation by UVA, analysing the role of QS in this phenomenon. We demonstrate that UVA induces key genes of the Las and Rhl QS systems at the transcriptional level. We also report that pelA and pslA genes, which are essential for biofilm formation and whose transcription depends in part on QS, are significantly induced under UVA exposure. Finally, the results demonstrate that in a relA strain (impaired for ppGpp production), the UVA treatment does not induce biofilm formation or QS genes, suggesting that the increase of biofilm formation due to exposure to UVA in P. aeruginosa could rely on a ppGpp-dependent QS induction.},
}
@article {pmid32494168,
year = {2020},
author = {Zhang, DX and Li, Y and Yang, XQ and Su, HY and Wang, Q and Zhang, ZH and Liu, YC and Tian, CL and Cui, CC and Liu, MC},
title = {In vitro Antibiotic Susceptibility, Virulence Genes Distribution and Biofilm Production of Staphylococcus aureus Isolates from Bovine Mastitis in the Liaoning Province of China.},
journal = {Infection and drug resistance},
volume = {13},
number = {},
pages = {1365-1375},
pmid = {32494168},
issn = {1178-6973},
abstract = {Purpose: The aim of this study was to identify the subtype, characterize the antimicrobial resistance, determine the virulence gene distribution, and analyze the biofilm production of Staphylococcus aureus isolates from bovine mastitis milk samples in the Liaoning Province of China.<br><br>Materials and Methods: In total, 56 Staph. aureus isolates were collected and identified in this study; the isolates were divided into different spa types based on the sequence of the polymorphic X region of the spa gene. Additionally, antimicrobial susceptibility was investigated using the broth microdilution method, and 18 virulence genes were detected using PCR. Biofilm formation was measured by spectrophotometry with crystal violet staining and observed using confocal laser scanning microscopy.<br><br>Results: There were 12.12% (56/462) milk samples that were positive for Staph. aureus. These isolates were nonsusceptible to sulfamethoxazole (100%), penicillin (76.9%), daptomycin (76.79%), clindamycin (69.64%), and oxacillin (60.71%); however, the majority of the isolates (80.4%) were susceptible to amoxicillin/clavulanate. The predominant virulence genes encoded the cytotoxins, hla (94.64%) and hlb (89.29%), and the adhesion factors clfA (89.29%), clfB (89.29%), and fnbB (80.36%). Comparatively, virulence genes related to other adhesion factors such as cna (8.93%) and enterotoxins, such as seg (26.79%), sea (16.07%), seb (7.14%), and sec (7.14%) were detected at relatively lower rates. The following eight spa types were identified: t267 (35.84%), t730 (22.64%), t518 (15.09%), t1190 (11.32%), t1456 (9.43%), t224 (1.88%), t9129 (1.88%), and t177 (1.88%). The highest biofilm production was observed for t267. Staph. aureus exhibited various patterns of biofilm formation, with the biofilm often being associated with a tower-shaped structure or a thicker biofilm.<br><br>Conclusion: Our results indicated that Staph. aureus isolates from dairy cows with mastitis in the Liaoning Province of China were non-susceptible to sulfamethoxazole, penicillin, daptomycin, oxacillin, and clindamycin. Additionally, the most prevalent subtype was t267, which displayed resistance to multiple antimicrobial agents and harbored several virulence genes, including clfA, clfB, fnbB, hla, and hlb.},
}
@article {pmid32493549,
year = {2020},
author = {Bernegossi, J and Fontana, CR and Caiaffa, KS and Duque, C and Chorilli, M},
title = {Inhibitory Effect of a KSL-W Peptide-Loaded Poloxamer 407-Based Microemulsions for Buccal Delivery on Fusobacterium nucleatum Biofilm.},
journal = {Journal of biomedical nanotechnology},
volume = {16},
number = {3},
pages = {390-397},
doi = {10.1166/jbn.2020.2896},
pmid = {32493549},
issn = {1550-7033},
abstract = {KSL-W peptide has demonstrated antibacterial and antifungal activity and inhibitory effects against oral biofilm. This study aimed to check out the effect of chlorhexidine (CLX) or KSL-W peptide-loaded poloxamer 407-based microemulsions for buccal delivery on Fusobacterium nucleatum (F. nucleatum) biofilm. The formulation (F) containing 10% copolymer poloxamer 407 dispersion (1%), 40% oleic acid and 50% PPG-5-CETETH-20 was characterized by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), rheology, bioadhesive and syringeability; and in the treatment of a biofilm produced by F. nucleatum. The darkfield images obtained by PLM and the SAXS curves with an extended peak indicated that the system was characteristic of microemulsions. In a continuous analysis, microemulsions exhibited Newtonian behavior. In frequency, the oscillatory analysis profile presented predominantly viscous behavior. Bioadhesive force detected in the analysis of F (7.4 ± 1.81 mN˙ s) and syringeability (17.83± 5.97 N · mm) being adequate values for buccal administration. After 4 h, KSL-W-loaded F shown over 20% higher effectiveness than chlorhexidine-loaded microemulsions. In conclusion, the KSL-W-loaded microemulsions showed a considerable reduction in F. nucleatum biofilm formation and presented promising structural properties for buccal drug delivery.},
}
@article {pmid32493365,
year = {2020},
author = {Engel, AS and Kranz, HT and Schneider, M and Tietze, JP and Piwowarcyk, A and Kuzius, T and Arnold, W and Naumova, EA},
title = {Biofilm formation on different dental restorative materials in the oral cavity.},
journal = {BMC oral health},
volume = {20},
number = {1},
pages = {162},
pmid = {32493365},
issn = {1472-6831},
abstract = {BACKGROUND: Bacterial biofilms adhere to all tissues and surfaces in the oral cavity. Oral biofilms are responsible for the decay of human dental structures and the inflammatory degeneration of the alveolar bone. Moreover, oral biofilms on artificial materials influence the lifespan of dental prostheses and restoratives.<br><br>METHODS: To investigate in vivo oral biofilm formation and growth, five different dental restorative materials were analyzed and compared to human enamel. The roughness of the materials and the human enamel control probe were measured at the start of the study. The dental restorative materials and the human enamel control probe were placed in dental splints and worn for 3 h, 24 h and 72 h.<br><br>RESULTS: Scanning electron microscopy (SEM) revealed major differences between oral biofilm formation and growth on the materials compared to those on human enamel. Microbiological analyses showed that bacterial strains differed between the materials. Significant differences were observed in the roughness of the dental materials.<br><br>CONCLUSIONS: It can be concluded that material roughness affects biofilm formation on dental surfaces and restoratives, but other factors, such as surface charge, surface energy and material composition, may also have an influence.},
}
@article {pmid32493283,
year = {2020},
author = {Ohsumi, T and Takenaka, S and Sakaue, Y and Suzuki, Y and Nagata, R and Hasegawa, T and Ohshima, H and Terao, Y and Noiri, Y},
title = {Adjunct use of mouth rinses with a sonic toothbrush accelerates the detachment of a Streptococcus mutans biofilm: an in vitro study.},
journal = {BMC oral health},
volume = {20},
number = {1},
pages = {161},
pmid = {32493283},
issn = {1472-6831},
support = {23592795//Japan Society for the Promotion of Science/ ; 16K20451//Japan Society for the Promotion of Science/ ; },
abstract = {BACKGROUND: The aim of this in vitro study was to examine the possible enhancement of the biofilm peeling effect of a sonic toothbrush following the use of an antimicrobial mouth rinse.<br><br>METHODS: The biofilm at a noncontact site in the interdental area was treated by sound wave convection with the test solution or by immersion in the solution. The biofilm peeling effect was evaluated by determining the bacterial counts and performing morphological observations. A Streptococcus mutans biofilm was allowed to develop on composite resin discs by cultivation with stirring at 50 rpm for 72 h. The specimens were then placed in recesses located between plastic teeth and divided into an immersion group and a combination group. The immersion group was treated with phosphate buffer, chlorhexidine digluconate Peridex™ (CHX) mouth rinse or Listerine® Fresh Mint (EO) mouth rinse. The combination group was treated with CHX or EO and a sonic toothbrush.<br><br>RESULTS: The biofilm thickness was reduced by approximately one-half compared with the control group. The combination treatment produced a 1 log reduction in the number of bacteria compared to the EO immersion treatment. No significant difference was observed in the biofilm peeling effect of the immersion group compared to the control group.<br><br>CONCLUSIONS: The combined use of a sonic toothbrush and a mouth rinse enhanced the peeling of the biofilm that proliferates in places that are difficult to reach using mechanical stress.},
}
@article {pmid32492906,
year = {2020},
author = {Ionescu, AC and Cazzaniga, G and Ottobelli, M and Garcia-Godoy, F and Brambilla, E},
title = {Substituted Nano-Hydroxyapatite Toothpastes Reduce Biofilm Formation on Enamel and Resin-Based Composite Surfaces.},
journal = {Journal of functional biomaterials},
volume = {11},
number = {2},
pages = {},
doi = {10.3390/jfb11020036},
pmid = {32492906},
issn = {2079-4983},
abstract = {Background: Toothpastes containing nano-hydroxyapatite (n-HAp) substituted with metal ions provide calcium and phosphate ions to dental hard tissues, reducing demineralization, and promoting remineralization. Few data are available about the effect of these bioactive compounds on oral microbiota. Methods: This in vitro study evaluated the influence of two commercially-available substituted n-HAp-based toothpastes (α: Zn-carbonate substituted n-HAp; β: F, Mg, Sr-carbonate substituted n-HAp) on early colonization (EC, 12 h) and biofilm formation (BF, 24 h) by oral microbiota. Controls were brushed with distilled water. Artificial oral microcosm and Streptococcus mutans biofilms were developed using human enamel and a resin-based composite (RBC) as adherence surfaces. Two test setups, a shaking multiwell plate and a modified drip-flow reactor (MDFR), were used to simulate clinical conditions during the night (low salivary flow and clearance) and daytime, respectively. Energy-dispersive X-ray spectrometry (EDS) was used to evaluate specimens' surfaces after toothpaste treatment. Fluoride release from β toothpaste was evaluated. Viable adherent biomass was quantified by MTT assay, and biofilms' morphology was highlighted using confocal microscopy. Results: EDS showed the presence of remnants from the tested toothpastes on both adherence surfaces. β toothpaste showed significantly lower EC and BF compared to control using the artificial oral microcosm model, while α toothpaste showed lower EC and BF compared to control, but higher EC and BF compared to β toothpaste. The effect shown by β toothpaste was, to a minimal extent, due to fluoride release. Interestingly, this result was seen on both adherence surfaces, meaning that the tested toothpastes significantly influenced EC and BF even on RBC surfaces. Furthermore, the effect of toothpaste treatments was higher after 12 h than 24 h, suggesting that toothbrushing twice a day is more effective than brushing once. Conclusions: The efficacy of these treatments in reducing microbial colonization of RBC surfaces may represent a promising possibility in the prevention of secondary caries.},
}
@article {pmid32492772,
year = {2020},
author = {Kostoglou, D and Protopappas, I and Giaouris, E},
title = {Common Plant-Derived Terpenoids Present Increased Anti-Biofilm Potential against Staphylococcus Bacteria Compared to a Quaternary Ammonium Biocide.},
journal = {Foods (Basel, Switzerland)},
volume = {9},
number = {6},
pages = {},
doi = {10.3390/foods9060697},
pmid = {32492772},
issn = {2304-8158},
abstract = {The antimicrobial actions of three common plant-derived terpenoids (i.e., carvacrol, thymol and eugenol) were compared to those of a typical quaternary ammonium biocide (i.e., benzalkonium chloride; BAC), against both planktonic and biofilm cells of two widespread Staphylococcus species (i.e., S. aureus and S. epidermidis). The minimum inhibitory and bactericidal concentrations (MICs, MBCs) of each compound against the planktonic cells of each species were initially determined, together with their minimum biofilm eradication concentrations (MBECs). Various concentrations of each compound were subsequently applied, for 6 min, against each type of cell, and survivors were enumerated by agar plating to calculate log reductions and determine the resistance coefficients (Rc) for each compound, as anti-biofilm effectiveness indicators. Sessile communities were always more resistant than planktonic ones, depending on the biocide and species. Although lower BAC concentrations were always needed to kill a specified population of either cell type compared to the terpenoids, for the latter, the required increases in their concentrations, to be equally effective against the biofilm cells with respect to the planktonic ones, were not as intense as those observed in the case of BAC, presenting thus significantly lower Rc. This indicates their significant anti-biofilm potential and advocate for their further promising use as anti-biofilm agents.},
}
@article {pmid32492592,
year = {2020},
author = {Hülsen, T and Sander, EM and Jensen, PD and Batstone, DJ},
title = {Application of purple phototrophic bacteria in a biofilm photobioreactor for single cell protein production: Biofilm vs suspended growth.},
journal = {Water research},
volume = {181},
number = {},
pages = {115909},
doi = {10.1016/j.watres.2020.115909},
pmid = {32492592},
issn = {1879-2448},
mesh = {Bacteria ; Biofilms ; Biomass ; Bioreactors ; Dietary Proteins ; *Photobioreactors ; *Proteobacteria ; Waste Disposal, Fluid ; Waste Water ; },
abstract = {Single cell protein (SCP), has been proposed as alternative to effectively upgrade and recycle organics and nutrients from wastewater. Biomass recovery is a critical issue, and recovery as a biofilm is effective in comparison with sedimentation of suspended biomass. This study aims to determine the applicability of purple phototrophic bacteria (PPB) biofilm on infra-red irradiated, submerged surfaces for the treatment of pre-settled red meat processing wastewater, and SCP generation. PPB removed up to 66% of COD and 42% of TN and TP during batch operation with total areal productivities between 15 and 20 gVS m-2 d-1 achieved. More than 60% of the total biomass grew attached (as biofilm) with the remainder being suspended. The biofilm can be harvested at around 160 gTS L-1 with high protein (>96 g L-1) and low ash contents (>4.0% compared to >30% in the wastewater). The compositions of attached and suspended biomass differed significantly, where the suspended fraction resembled the wastewater composition (e.g. in terms of inert components). The PPB community was similar in the suspended and biofilm fractions while the biofilm had higher relative abundance of PPB representatives (57% vs 43%). A consistent product composition is highly relevant for the manufacturer and ultimately determines the value as feed, feed additive, or supplement.},
}
@article {pmid32492459,
year = {2020},
author = {Meng, J and Xu, J and Chen, J},
title = {The role of osmoregulated periplasmic glucans in the biofilm antibiotic resistance of Yersinia enterocolitica.},
journal = {Microbial pathogenesis},
volume = {147},
number = {},
pages = {104284},
doi = {10.1016/j.micpath.2020.104284},
pmid = {32492459},
issn = {1096-1208},
abstract = {The formation of biofilms by bacteria is of great significance because it involves many physiological changes that serve to protect the cells from various stresses. One of the best-known biofilm-specific properties of bacteria is that bacteria that grow in biofilms are generally more resistant to antibiotics than their planktonic counterparts. In a previous study, osmoregulated periplasmic glucans (OPGs), catalyzed by the opgGH operon, were identified and found to function in Rcs signalling in Yersinia enterocolitica. In this study, the possible contribution of OPGs to antimicrobial resistance of Y. enterocolitica biofilms were investigated, and the results showed that OPGs, especially when overexpressed, conferred a high level of biofilm resistance to two different classes of antibiotics onto Y. enterocolitica. Subsequent analysis revealed that OPGs regulated the biofilm architecture in Y. enterocolitica by promoting the bacteria to form large cell aggregates. Moreover, the opgGH genes in biofilms showed higher expression than in planktonic cultures. OPGs were required to induce the expression of genes related to flagella, extracellular polysaccharide, and c-di-GMP biosynthesis in Y. enterocolitica biofilms and this effect was more significant when OPGs were overproduced. The current investigation showed an extension in the biological role of OPGs in Y. enterocolitica and provided a strong theoretical basis to further study this resistance mechanism at the molecular level to identify new drug targets or disinfectants for the treatment of infections caused by Y. enterocolitica within biofilms.},
}
@article {pmid32491277,
year = {2020},
author = {Earl, C and Arnaouteli, S and Bamford, NC and Porter, M and Sukhodub, T and MacPhee, CE and Stanley-Wall, NR},
title = {The majority of the matrix protein TapA is dispensable for Bacillus subtilis colony biofilm architecture.},
journal = {Molecular microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mmi.14559},
pmid = {32491277},
issn = {1365-2958},
support = {BB/M013774/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/N022254/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R012415/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; 097818/Z/11/WT_/Wellcome Trust/United Kingdom ; },
abstract = {Biofilm formation is a co-operative behaviour, where microbial cells become embedded in an extracellular matrix. This biomolecular matrix helps manifest the beneficial or detrimental outcome mediated by the collective of cells. Bacillus subtilis is an important bacterium for understanding the principles of biofilm formation. The protein components of the B. subtilis matrix include the secreted proteins BslA, which forms a hydrophobic coat over the biofilm, and TasA, which forms protease-resistant fibres needed for structuring. TapA is a secreted protein also needed for biofilm formation and helps in vivo TasA-fibre formation but is dispensable for in vitro TasA-fibre assembly. We show that TapA is subjected to proteolytic cleavage in the colony biofilm and that only the first 57 amino acids of the 253-amino acid protein are required for colony biofilm architecture. Through the construction of a strain which lacks all eight extracellular proteases, we show that proteolytic cleavage by these enzymes is not a prerequisite for TapA function. It remains unknown why TapA is synthesised at 253 amino acids when the first 57 are sufficient for colony biofilm structuring; the findings do not exclude the core conserved region of TapA having a second role beyond structuring the B. subtilis colony biofilm.},
}
@article {pmid32489278,
year = {2020},
author = {Bin, C and Al-Dhabi, NA and Esmail, GA and Arokiyaraj, S and Arasu, MV},
title = {Potential effect of Allium sativum bulb for the treatment of biofilm forming clinical pathogens recovered from periodontal and dental caries.},
journal = {Saudi journal of biological sciences},
volume = {27},
number = {6},
pages = {1428-1434},
pmid = {32489278},
issn = {1319-562X},
abstract = {Biofilm producing clinical bacterial isolates were isolated from periodontal and dental caries samples and identified as, Lactobacillus acidophilus, Streptococcus sanguis, S. salivarius, S. mutansand Staphylococcus aureus. Among the identified bacterial species, S. aureus and S. mutansshowed strong biofilm producing capacity. The other isolated bacteria, Streptococcus sanguis, S. salivarius showed moderate biofilm formation. These pathogens were subjected for the production of extracellular polysaccharides (EPS) in nutrient broth medium and the strain S. aureus synthesized more amounts of EPS (610 ± 11.2 µg/ml) than S. sanguis (480 ± 5.8 µg/ml).EPS production was found to be less in S. salivarius (52 ± 3.8 µg/ml).The solvent extract of A. sativum bulb showed the phytochemicals such as, carbohydrate, total protein, alkaloids, saponins, flavonoids, tannins and sterioids. The solvent extract of A. sativum bulb showed wide ranges of activity against the selected dental pathogens. The difference in antibacterial activity of the solvent extract revealed differences in solubility of phytochemicals in organic solvents. Ethanol extract was highly active againstS. aureus (25 ± 2 mm). The Minimum Inhibitory Concentration (MIC) of crude garlic bulb varied widely and this clearly showed that bacteria exhibits different level of susceptibility to secondary metabolites. MIC value ranged between 20 ± 2 mg/ml and 120 ± 6 mg/ml and Minimum Bactericidal Concentration (MBC) value ranged from 60 ± 5 mg/l to 215 ± 7 mg/ml. To conclude, A. sativum bulb can be effectively used to treat periodontal and dental caries infections.},
}
@article {pmid32488138,
year = {2020},
author = {Warraich, AA and Mohammed, AR and Perrie, Y and Hussain, M and Gibson, H and Rahman, A},
title = {Evaluation of anti-biofilm activity of acidic amino acids and synergy with ciprofloxacin on Staphylococcus aureus biofilms.},
journal = {Scientific reports},
volume = {10},
number = {1},
pages = {9021},
pmid = {32488138},
issn = {2045-2322},
support = {BB/M017044/1//RCUK | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; BB/M017044/1//RCUK | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; BB/M017044/1//RCUK | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; BB/M017044/1//RCUK | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; BB/M017044/1//RCUK | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; },
abstract = {Acidic amino acids, aspartic acid (Asp) and glutamic acid (Glu) can enhance the solubility of many poorly soluble drugs including ciprofloxacin (Cip). One of the mechanisms of resistance within a biofilm is retardation of drug diffusion due to poor penetration across the matrix. To overcome this challenge, this work set to investigate novel counter ion approach with acidic amino acids, which we hypothesised will disrupt the biofilm matrix as well as simultaneously improve drug effectiveness. The anti-biofilm activity of D-Asp and D-Glu was studied on Staphylococcus aureus biofilms. Synergistic effect of combining D-amino acids with Cip was also investigated as a strategy to overcome anti-microbial resistance in these biofilms. Interestingly at equimolar combinations, D-Asp and D-Glu were able to significantly disperse (at 20 mM and 40 mM) established biofilms and inhibit (at 10 mM, 20 mM and 40 mM) new biofilm formation in the absence of an antibiotic. Moreover, our study confirmed L-amino acids also exhibit anti-biofilm activity. The synergistic effect of acidic amino acids with Cip was observed at lower concentration ranges (<40 mM amino acids and <90.54 µM, respectively), which resulted in 96.89% (inhibition) and 97.60% (dispersal) reduction in CFU with exposure to 40 mM amino acids. Confocal imaging indicated that the amino acids disrupt the honeycomb-like extracellular DNA (eDNA) meshwork whilst also preventing its formation.},
}
@article {pmid32487404,
year = {2020},
author = {Baig, U and Ansari, MA and Gondal, MA and Akhtar, S and Khan, FA and Falath, WS},
title = {Single step production of high-purity copper oxide-titanium dioxide nanocomposites and their effective antibacterial and anti-biofilm activity against drug-resistant bacteria.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {113},
number = {},
pages = {110992},
doi = {10.1016/j.msec.2020.110992},
pmid = {32487404},
issn = {1873-0191},
abstract = {In the present research work, copper oxide-titanium dioxide nanocomposites were synthesized for the first time using advanced pulsed laser ablation in liquid (PLAL) technique for disinfection of drug-resistant pathogenic waterborne biofilm-producing bacterial strains. For this, a series of copper oxide-titanium dioxide nanocomposites were synthesized by varying the composition of copper oxide (5%, 10%, and 20%) with titanium dioxide. The pure titanium dioxide and copper oxide-titanium dioxide nanocomposites were characterized by advanced instrumental techniques. XRD, TEM, FE-SEM, EDX, elemental mapping and XPS analysis results consistently revealed the successful formation of copper oxide-titanium dioxide nanocomposites using PLAL technique. The antibacterial and antibiofilm activities of pure titanium dioxide and copper oxide-titanium dioxide nanocomposites were investigated against biofilm-producing strains of Methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa by various methods. Our results revealed that the PLAL synthesized copper oxide-titanium dioxide nanocomposites showed enhanced anti-biofilm and antibacterial activity compared to pure titanium dioxide in a dose-dependent manner against targeted pathogens. Furthermore, the effects of pure titanium dioxide and copper oxide-titanium dioxide nanocomposites on bacterial morphology, biofilm formation, aggregation and their colonization by targeted pathogens were also examined using scanning electron microscopy. Microscopic images clearly showed that the cell envelope of almost all the cells were rumples, rough, had irregularities and abnormal appearance with the major damage being characterized by the formation of &quot;pits&quot;. Many depressions and indentations were also seen in their cell envelope and the original shape of Pseudomonas aeruginosa cells changed from normal rod to swollen, large and elongated which indicates the loss of membrane integrity and damage of cell wall and membrane. The findings suggested that PLAL synthesized copper oxide-titanium dioxide nanocomposites have good potential for removal of biofilm or killing of pathogenic bacteria in water distribution network and for wastewater treatment, hospital and environmental applications. In addition, cytotoxic activity of pure TiO2 and PLAL synthesized copper oxide-titanium dioxide nanocomposites against normal and healthy cells (HEK-293) and cancerous cells (HCT-116) were also evaluated by MTT assay. The MTT assay results showed no cytotoxic effects on HEK-293 cells, which suggest TiO2 and PLAL synthesized copper oxide-titanium dioxide nanocomposites are non-toxic to the normal cells.},
}
@article {pmid32487374,
year = {2020},
author = {Awasthi, A and Sharma, P and Jangir, L and Kamakshi, and Awasthi, G and Awasthi, KK and Awasthi, K},
title = {Dose dependent enhanced antibacterial effects and reduced biofilm activity against Bacillus subtilis in presence of ZnO nanoparticles.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {113},
number = {},
pages = {111021},
doi = {10.1016/j.msec.2020.111021},
pmid = {32487374},
issn = {1873-0191},
abstract = {Bacterial biofilms are self-produced matrix of sticky extracellular polymeric substances. They result in fouling in the food industry, water treatment plants, and possess significant environmental and industrial impacts. Nanoparticles have shown immense potential and have been effective in combating bacterial biofilm, which is the common cause of drug resistance development, biofouling in water treatment plants and the food industry. Hence, in order to explore the same, Zinc oxide nanoparticles have been synthesized by chemical synthesis method and their action against Bacillus subtilis biofilm formation was evaluated in this study by crystal violet and ROS assay. The dose-dependent reduction in biofilm biomass and density was observed as a result of nanoparticle exposure. There was considerable reduction in biofilm formation after treatment with ZnO nanoparticles. Change in surface morphology of the Bacillus subtilis cells was observed which could be due to oxidative stress induced by ZnO nanoparticles. The oxidative stress was estimated by measurement of catalase activity that also showed dose-dependent decrease.},
}
@article {pmid32486591,
year = {2020},
author = {Liu, MJ and Zhang, YL and Wan, XY},
title = {[Research progress on methicillin-resistant Staphylococcus aureus biofilm].},
journal = {Zhonghua nei ke za zhi},
volume = {59},
number = {6},
pages = {473-476},
doi = {10.3760/cma.j.cn112138-20190704-00470},
pmid = {32486591},
issn = {0578-1426},
}
@article {pmid32485913,
year = {2020},
author = {Cai, H and Wang, Y and Wu, K and Guo, W},
title = {Enhanced Hydrophilic and Electrophilic Properties of Polyvinyl Chloride (PVC) Biofilm Carrier.},
journal = {Polymers},
volume = {12},
number = {6},
pages = {},
doi = {10.3390/polym12061240},
pmid = {32485913},
issn = {2073-4360},
abstract = {Polyvinyl chloride (PVC) biofilm carrier is used as a carrier for bacterial adsorption in wastewater treatment. The hydrophilicity and electrophilicity of its surface play an important role in the adsorption of bacteria. The PVC biofilm carrier was prepared by extruder, and its surface properties were investigated. In order to improve the hydrophilicity and electrophilic properties of the PVC biofilm carrier, polyvinyl alcohol (PVA) and cationic polyacrylamide (cPAM) were incorporated into polyvinyl chloride (PVC) by blending. Besides, the surface area of the PVC biofilm carrier was increased by azodicarbonamide modified with 10% by weight of zinc oxide (mAC). The surface contact angle of PVC applied by PVA and cPAM at 5 wt %, 15 wt % was 81.6°, which was 18.0% lower than pure PVC. It shows the significant improvement of the hydrophilicity of PVC. The zeta potential of pure PVC was -9.59 mV, while the modified PVC was 14.6 mV, which proves that the surface charge of PVC changed from negative to positive. Positive charge is more conducive to the adsorption of bacteria. It is obvious from the scanning electron microscope (SEM) images that holes appeared on the surface of the PVC biofilm carrier after adding mAC, which indicates the increase of PVC surface area.},
}
@article {pmid32485401,
year = {2020},
author = {Xiao, B and Zou, Z and Bhandari, J and Zhang, Y and Yan, G},
title = {Exposure to diode laser (810nm) affects the bacterial adherence and biofilm formation in a E. faecalis biofilm model.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {101772},
doi = {10.1016/j.pdpdt.2020.101772},
pmid = {32485401},
issn = {1873-1597},
abstract = {BACKGROUND: A large number of studies have shown that diode laser can effectively killEnterococcus faecalis (E. faecalis). However, to our knowledge there has been little information regarding high-level analysis of sterilization mechanism on E. faecalis biofilm models after laser irradiation. This study provides emphasis on the E. faecalis viability and exopolysaccharide content after laser irradiation. It also aims to examine whether diode laser affects the biofilm formation and adherence of E. faecalis biofilm at the level of gene expression.<br><br>METHODS: E. faecalis (ATCC 29212) was inoculated for biofilm formation. After growing for 48 h, the biofilms were submitted to the following treatments, twice daily (n = 6): (i) Diode laser with energy densities as 28.7 J/cm2; (ii) 1% sodium hypochlorite (NaOCl) was used as a positive control; (iii) 0.9% physiological saline (NaCl) was used as a negative control. After 120 h of biofilm growth, bactericidal activity of diode laser was evaluated by using plate count method and scanning electron microscopy (SEM). The distribution of extracellular polysaccharide was assessed by Confocal laser scanning microscopy (CLSM). Anthrone method was used to quantify the amount of water-soluble exopolysaccharide (WSE) and water-insoluble exopolysaccharides (WIE) in E. faecalis. Real-time quantitative polymerase chain reaction (RT-qPCR) was employed to assess transcription of genes (gelE, ace and esp) related to formation and adherence of E. faecalis biofilm.<br><br>RESULTS: Compared with NaCl, diode laser significantly destabilizedE. faecalis biofilm, which showing a decrease in the number of bacteria and inhibiting the adherence of biofilm (p < 0.05). From Anthrone method and CLSM, the study found that diode laser lowered the concentration of WSE and WIE in biofilms (p < 0.05). In addition, transcription of gene gelE, ace and esp were also reduced after irradiation of diode laser (p < 0.05).<br><br>CONCLUSION: By inhibiting the synthesis of WIE and WSE, diode laser may reduce the formation of E. faecalis biofilm. The expression of specific genes (gelE, ace and esp) involved in bacterial adherence and biofilm formation were down regulated under the exposure to diode laser (810 nm), which in turn is expected to decrease the pathogenicity of E. faecalis.},
}
@article {pmid32484808,
year = {2020},
author = {Qin, H and Liu, Y and Cao, X and Jiang, J and Lian, W and Qiao, D and Xu, H and Cao, Y},
title = {RpoS is a pleiotropic regulator of motility, biofilm formation, exoenzymes, siderophore and prodigiosin production, and trade-off during prolonged stationary phase in Serratia marcescens.},
journal = {PloS one},
volume = {15},
number = {6},
pages = {e0232549},
pmid = {32484808},
issn = {1932-6203},
abstract = {Prodigiosin is an important secondary metabolite produced by Serratia marcescens. It can help strains resist stresses from other microorganisms and environmental factors to achieve self-preservation. Prodigiosin is also a promising secondary metabolite due to its pharmacological characteristics. However, pigmentless S. marcescens mutants always emerge after prolonged starvation, which might be a way for the bacteria to adapt to starvation conditions, but it could be a major problem in the industrial application of S. marcescens. To identify the molecular mechanisms of loss of prodigiosin production, two mutants were isolated after 16 days of prolonged incubation of wild-type (WT) S. marcescens 1912768R; one mutant (named 1912768WR) exhibited reduced production of prodigiosin, and a second mutant (named 1912768W) was totally defective. Comparative genomic analysis revealed that the two mutants had either mutations or deletions in rpoS. Knockout of rpoS in S. marcescens 1912768R had pleiotropic effects. Complementation of rpoS in the ΔrpoS mutant further confirmed that RpoS was a positive regulator of prodigiosin production and that its regulatory role in prodigiosin biosynthesis was opposite that in Serratia sp. ATCC 39006, which had a different type of pig cluster; further, rpoS from Serratia sp. ATCC 39006 and other strains complemented the prodigiosin defect of the ΔrpoS mutant, suggesting that the pig promoters are more important than the genes in the regulation of prodigiosin production. Deletion of rpoS strongly impaired the resistance of S. marcescens to stresses but increased membrane permeability for nutritional competence; competition assays in rich and minimum media showed that the ΔrpoS mutant outcompeted its isogenic WT strain. All these data support the idea that RpoS is pleiotropic and that the loss of prodigiosin biosynthesis in S. marcescens 1912768R during prolonged incubation is due to a mutation in rpoS, which appears to be a self-preservation and nutritional competence (SPANC) trade-off.},
}
@article {pmid32484655,
year = {2020},
author = {Zhang, J and Chen, C and Chen, J and Zhou, S and Zhao, Y and Xu, M and Xu, H},
title = {Dual Mode of Anti-Biofilm Action of G3 against Streptococcus mutans.},
journal = {ACS applied materials &amp; interfaces},
volume = {12},
number = {25},
pages = {27866-27875},
doi = {10.1021/acsami.0c00771},
pmid = {32484655},
issn = {1944-8252},
abstract = {Oral biofilms, formed by multiple microorganisms and their extracellular polymeric substances, seriously affect people's life. The emergence of the resistance of biofilms to conventional antibiotics and their side effects on the oral cavity have posed a great challenge in the treatment of dental diseases. Recently, antimicrobial peptides have been recognized as promising alternatives to conventional antibiotics due to their broad antibacterial spectrum, high antibacterial activity, and specific mechanism. However, the research of their anti-biofilm behaviors is still in its infancy, and the underlying mechanism remains unclear. In this study, we investigated the anti-biofilm activities of a designed helical peptide (G3) against Streptococcus mutans (S. mutans), one of the primary causative pathogens of caries. The results indicated that G3 inhibited S. mutans biofilm formation by interfering with different stages of biofilm development. At the initial stage, G3 inhibited the bacterial adhesion by decreasing the bacterial surface charges, hydrophobicity, membrane integrity, and adhesion-related gene transcription. At the later stage, G3 interacted with extracellular DNA to destabilize the 3D architecture of mature biofilms and thus dispersed them. The high activity of G3 against S. mutans biofilms, along with its specific modes of action, endows it great application potential in preventing and treating dental plaque diseases.},
}
@article {pmid32484105,
year = {2020},
author = {Al Marjania, MF and Kouhsari, E and Ali, FS and Authman, SH},
title = {Evaluation of type II toxin-antitoxin systems, antibiotic resistance profiles, and biofilm quorum sensing genes in Acinetobacter baumannii isolates in Iraq.},
journal = {Infectious disorders drug targets},
volume = {},
number = {},
pages = {},
doi = {10.2174/1871526520666200525170318},
pmid = {32484105},
issn = {2212-3989},
abstract = {BACKGROUND: Bacterial Toxin-Antitoxin (TAs) systems are extensive two-component elements in the bacterial genome, which involved in many key biological functions including growth arrest, survival, biofilm formation, plasmid maintenance, defense against phages, persistence and virulence.<br><br>AIM: This study aimed to assess the molecular determinants involved in TAs, biofilm quorum sensing, and antibiotic resistance profiles in Acinetobacter baumannii isolated from Baghdad`s hospitals in Iraq.<br><br>METHODS: A total of 127 A. baumannii isolates were collected from 2160 different clinical samples. The antimicrobial susceptibility test was performed using disk diffusion test. All isolates were characterized for molecular determinants involved in TAs and biofilm formation using the well-known PCR-based sequencing assay.<br><br>RESULTS: A high multi-drug resistant (MDR) (96.06%; 122/127) and imipenem resistance (84.25%; 107/127) rates were observed from A.baumannii isolates. Results showed the presence of rhlIR gene in three isolates (2.36%), and lasIR gene appeared in two isolates (1.57%) isolates, whilst, mazEF, ccdAB, and relBE genes have not detected among isolates.<br><br>CONCLUSION: A high MDR and imipenem resistance rates within a low prevalence of rhlIR, and lasIR genes could be found in clinical A. baumannii isolates from some of Iraqi hospitals.},
}
@article {pmid32482721,
year = {2020},
author = {Labine, M and DePledge, L and Feirer, N and Greenwich, J and Fuqua, C and Allen, KD},
title = {Enzymatic and Mutational Analysis of the PruA Pteridine Reductase Required for Pterin-Dependent Control of Biofilm Formation in Agrobacterium tumefaciens.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00098-20},
pmid = {32482721},
issn = {1098-5530},
abstract = {Pterins are ubiquitous biomolecules with diverse functions including roles as cofactors, pigments, and redox mediators. Recently, a novel pterin-dependent signaling pathway that controls biofilm formation was identified in the plant pathogen, Agrobacterium tumefaciens A key player in this pathway is a pteridine reductase termed PruA, where its enzymatic activity has been shown to control surface attachment and limit biofilm formation. Here, we biochemically characterize PruA to investigate the catalytic properties and substrate specificity of this pteridine reductase. PruA demonstrates maximal catalytic efficiency with dihydrobiopterin and comparable activities with the stereoisomers dihydromonapterin and dihydroneopterin. Since A. tumefaciens does not synthesize or utilize biopterins, the likely physiological substrate is dihydromonapterin or dihydroneopterin, or both. Notably, PruA does not exhibit pteridine reductase activity with dihydrofolate or fully oxidized pterins. Site-directed mutagenesis studies of a conserved tyrosine residue, the key component of a putative catalytic triad, indicate that this tyrosine is not directly involved in PruA catalysis but may be important for substrate or cofactor binding. Additionally, mutagenesis of the arginine residue in the N-terminal TGX3RXG motif significantly reduces the catalytic efficiency of PruA, supporting its proposed role in pterin binding and catalysis. Finally, we report the enzymatic characterization of PruA homologs from Pseudomonas aeruginosa and Brucella abortus, thus expanding the roles and potential significance of pteridine reductases in diverse bacteria.Importance Biofilms are complex multicellular communities that are formed by diverse bacteria. In the plant pathogen, Agrobacterium tumefaciens, the transition from a free-living motile state to a non-motile biofilm state is governed by a novel signaling pathway involving small molecules called pterins. The involvement of pterins in biofilm formation is unexpected and prompts many questions about the molecular details of this pathway. This work biochemically characterizes the PruA pteridine reductase involved in the signaling pathway to reveal its enzymatic properties and substrate preference, thus providing important insight into pterin biosynthesis and its role in A. tumefaciens biofilm control. Additionally, the enzymatic characteristics of related pteridine reductases from mammalian pathogens are examined to uncover potential roles of these enzymes in other bacteria.},
}
@article {pmid32482286,
year = {2020},
author = {Fiamengo, TE and Runcan, EE and Premanandan, C and Blawut, B and Coutinho da Silva, MA},
title = {Evaluation of Biofilm Production by Escherichia coli Isolated From Clinical Cases of Canine Pyometra.},
journal = {Topics in companion animal medicine},
volume = {39},
number = {},
pages = {100429},
doi = {10.1016/j.tcam.2020.100429},
pmid = {32482286},
issn = {1946-9837},
abstract = {Many Escherichia coli (E. coli) strains produce biofilm that confers antimicrobial resistance. However, studies of biofilm production by E. coli from canine pyometra are lacking. Objectives were to elucidate the role of biofilm production by E. coli in pyometra by: (1) assessing the ability of E. coli to produce biofilm in vitro, and (2) confirming biofilm in situ. Endometrial biopsies were obtained from bitches with pyometra and preserved for microscopic analysis (n = 25). An endometrial swab was submitted for aerobic culture. Samples with confirmed E. coli were evaluated further for biofilm production in vitro and in vivo. Seventy percent of cases (16/23) resulted in pure growth of 1 or 2 E. coli strains, totaling 20 isolates. Fifteen isolates (15/20, 75%) had higher optical densities then negative controls (P < .05). On histopathology, all tissues exhibited endometrial inflammation and mucus was located within endometrial glands and occasionally overlying epithelium on 14 slides (14/16, 88%). Bacteria was noted in 50% of slides (8/16). During FISH acellular debris within the uterine lumen consistent with biofilm was noted on 94% of samples (15/16) and E coli was positively identified on all samples (15/15). Areas suggestive of the presence of biofilm were observed on all samples on scanning electron microscopy; but, bacteria consistent with E. coli were only visualized in 9 samples (9/16, 56%). In conclusion, we demonstrated that relevant strains of E. coli produce biofilm in vitro and in vivo, which may be considered in the development of new pyometra treatments aimed at disrupting these E. coli biofilm.},
}
@article {pmid32479963,
year = {2020},
author = {Liu, C and Yan, B and Duan, J and Hou, B},
title = {Biofilm inhibition effect of an ivermectin/silyl acrylate copolymer coating and the colonization dynamics.},
journal = {The Science of the total environment},
volume = {736},
number = {},
pages = {139599},
doi = {10.1016/j.scitotenv.2020.139599},
pmid = {32479963},
issn = {1879-1026},
abstract = {Ivermectin is now being used as a substitute for toxic organic biocide in marine antifouling coatings due to its environmentally friendly nature and the efficacy against parasites. However, the release performance of ivermectin from the hydrolyzed acrylic-based resin into the seawater is not clear. Moreover, the efficiency and mechanism of ivermectin in preventing biofilm or slime formation have not been fully investigated. In this study, a coating was developed by mixing ivermectin with an acrylic-based resin, silyl acrylate copolymer, and a 45-day in situ antifouling test was conducted in the Yellow Sea. Direct observation and confocal microscope investigation indicated that the polymer coating with ivermectin was effective against biofilm formation. High-throughput sequencing analysis showed that ivermectin can selectively inhibit the adhesion of microorganisms. Abundances of Gammaproteobacteria and Alphaproteobacteria decreased significantly with the increased concentration of ivermectin. As for the eukaryote community, species of Stolidobranchia and unidentified_Bacillariophyceae were proved to be sensitive to ivermectin. Therefore, the ivermectin/silyl acrylate copolymer coating is a promising substitute for marine antifouling material.},
}
@article {pmid32479710,
year = {2020},
author = {Jeronimo, LP and Choi, MR and Yeon, SH and Park, SK and Yoon, YH and Choi, SH and Kim, HJ and Jang, IT and Park, JK and Rha, KS and Kim, YM},
title = {Effects of povidone-iodine composite on the elimination of bacterial biofilm.},
journal = {International forum of allergy &amp; rhinology},
volume = {10},
number = {7},
pages = {884-892},
doi = {10.1002/alr.22568},
pmid = {32479710},
issn = {2042-6984},
support = {2017-1919-01//Chungnam National University/ ; 2017M3A9G5083517).//National Research Foundation of Korea/ ; },
abstract = {BACKGROUND: Povidone-iodine (PVP-I) is well known as an antiseptic and exhibits extensive activity against various pathogens. However, due to its uniquely unpleasant nature, it cannot be used locally to deactivate various sinonasal pathogens. Therefore, we developed a PVP-I composite that blocks the unpleasant odor of PVP-I for use as a local antiseptic in the sinonasal cavity and evaluated its effect on bacterial biofilm's formation and elimination in in vivo and in vitro models.<br><br>METHODS: MTT, lactate dehydrogenase, and live/dead staining assay were performed to examine the cellular toxicity of PVP-I composites on the primary human nasal epithelial and RPMI 2650 cells. Crystal violet assay was performed to quantify bacterial biofilm after treating with various agents, including PVP-I and antibiotics. Hematoxylin-and-eosin staining, live/dead staining assay, and scanning electron microscopy were conducted to evaluate the effect of PVP-I on biofilm formation in a mice biofilm model.<br><br>RESULTS: It was observed that the PVP-I composite did not have any significant toxic effect on the nasal epithelial cells. Furthermore, the PVP-I composite effectively inhibited the formation of bacterial biomass within a dose-dependent manner after 48 hours of incubation with Pseudomonas aeruginosa and Staphylococcus aureus. In mice, it effectively eliminated biofilm from the mucosa of the nasal cavity and maxillary sinus at the tested concentrations.<br><br>CONCLUSION: The results of this study indicate that the PVP-I composite is a promising compound that could be used locally to prevent the formation of biofilms and to eliminate them from the sinonasal cavity.},
}
@article {pmid32479611,
year = {2020},
author = {Shakerimoghaddam, A and Razavi, D and Rahvar, F and Khurshid, M and Moghadam Ostadkelayeh, S and Esmaeili, SA and Khaledi, A and Eshraghi, M},
title = {Evaluate the effect of zinc oxide and silver nanoparticles (ZnO-Ag NPs) on biofilm and icaA gene expression in methicillin-resistant Staphylococcus aureus (MRSA) isolated from burn wound infection.},
journal = {Journal of burn care &amp; research : official publication of the American Burn Association},
volume = {},
number = {},
pages = {},
doi = {10.1093/jbcr/iraa085},
pmid = {32479611},
issn = {1559-0488},
abstract = {Methicillin-resistant Staphylococcus aureus is the cause of nosocomial and community-acquired infections. This study aimed to evaluate the effect of zinc oxide and silver nanoparticles (ZnO-Ag NPs) on biofilms formation and icaA gene expression in methicillin-resistant S. aureus (MRSA).},
}
@article {pmid32479089,
year = {2020},
author = {Nguyen, BVG and Nagakubo, T and Toyofuku, M and Nomura, N and Utada, AS},
title = {Synergy between Sophorolipid Biosurfactant and SDS Increases the Efficiency of P. aeruginosa Biofilm Disruption.},
journal = {Langmuir : the ACS journal of surfaces and colloids},
volume = {36},
number = {23},
pages = {6411-6420},
doi = {10.1021/acs.langmuir.0c00643},
pmid = {32479089},
issn = {1520-5827},
abstract = {Biofilms are communities of bacteria encased in self-secreted extracellular polymeric substances (EPS) that adhere stubbornly to submerged surfaces. Once established, these communities can cause serious chronic illnesses in medical settings, while they can promote corrosion and biofouling in industrial settings. Due to the difficulty of their removal, strongly oxidizing chemicals and detergents can be used to degrade and remove biofilms by killing the cells and degrading the matrix; however, the choice of compounds is limited in delicate environments due to the potential damage they may cause. In the case of detergents, most are synthesized from nonrenewable petrochemicals that have a degree of aquatic toxicity. There is a growing need to identify and characterize alternatives to synthetic surfactants. Biosurfactants, which are surfactants produced by microorganisms, are a promising alternative since they can be synthesized from renewable resources, have low environmental toxicity, and have been shown to have higher degrees of specificity in the mechanism of action. Sophorolipids are a class of glycolipid surfactants produced by yeast that have demonstrated great promise due to large yields from renewable feedstocks and for antimicrobial properties; however, the effect of the application of sophorolipids to Gram-negative bacterial biofilms has not been well studied. We investigate the antibiofilm properties of sophorolipids by demonstrating its ability to cause the catastrophic disruption of Pseudomonas aeruginosa PAO1 biofilms in microfluidic channels. We show that while sophorolipids inflict little damage to the bacteria, they weaken the EPS biofilm matrix, leading to surface-detachment and breakup of the biofilm. Furthermore, we find that sophorolipids act cooperatively with the widely used surfactant, sodium dodecyl sulfate. When combined, concentrations ∼100-fold lower than the minimum effective concentration, when used independently, recover potency. Biosurfactants are typically expensive to produce, thus our work demonstrates a means to improve efficacy while simultaneously reducing both cost and the amount of environmentally harmful substances used.},
}
@article {pmid32477314,
year = {2020},
author = {Qu, Y and Li, Y and Cameron, DR and Easton, CD and Zhu, X and Zhu, M and Salwiczek, M and Muir, BW and Thissen, H and Daley, A and Forsythe, JS and Peleg, AY and Lithgow, T},
title = {Hyperosmotic Infusion and Oxidized Surfaces Are Essential for Biofilm Formation of Staphylococcus capitis From the Neonatal Intensive Care Unit.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {920},
pmid = {32477314},
issn = {1664-302X},
abstract = {Staphylococcus capitis is an opportunistic pathogen often implicated in bloodstream infections in the neonatal intensive care unit (NICU). This is assisted by its ability to form biofilms on indwelling central venous catheters (CVC), which are highly resistant to antibiotics and the immune system. We sought to understand the fundamentals of biofilm formation by S. capitis in the NICU, using seventeen clinical isolates including the endemic NRCS-A clone and assessing nine commercial and two modified polystyrene surfaces. S. capitis clinical isolates from the NICU initiated biofilm formation only in response to hyperosmotic conditions, followed by a developmental progression driven by icaADBC expression to establish mature biofilms, with polysaccharide being their major extracellular polymer substance (EPS) matrix component. Physicochemical features of the biomaterial surface, and in particular the level of the element oxygen present on the surface, significantly influenced biofilm development of S. capitis. A lack of highly oxidized carbon species on the surface prevented the immobilization of S. capitis EPS and the formation of mature biofilms. This information provides guidance in regard to the preparation of hyperosmolar total parenteral nutrition and the engineering of CVC surfaces that can minimize the risk of catheter-related bloodstream infections caused by S. capitis in the NICU.},
}
@article {pmid32477292,
year = {2020},
author = {Adnan, M and Patel, M and Deshpande, S and Alreshidi, M and Siddiqui, AJ and Reddy, MN and Emira, N and De Feo, V},
title = {Effect of Adiantum philippense Extract on Biofilm Formation, Adhesion With Its Antibacterial Activities Against Foodborne Pathogens, and Characterization of Bioactive Metabolites: An in vitro-in silico Approach.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {823},
pmid = {32477292},
issn = {1664-302X},
abstract = {Adiantum philippense (A. philippense), an ethnomedicinally important fern, has become an interesting herb in the search for novel bioactive metabolites, which can also be used as therapeutic agents. Primarily, in this study, A. philippense crude extract was screened for its phytochemical constituents, antagonistic potential, and effect on bacterial adhesion and biofilm formation against common food pathogens. Phytochemical profiling of A. philippense was carried out by using High Resolution-Liquid Chromatography and Mass Spectroscopy (HR-LCMS) followed by antibacterial activity via agar cup/well diffusion, broth microdilution susceptibility methods, and growth curve analysis. Antibiofilm potency and efficacy were assessed on the development, formation, and texture of biofilms through light microscopy, fluorescent microscopy, scanning electron microscopy, and the assessment of exopolysaccharide production. Correspondingly, a checkerboard test was performed to evaluate the combinatorial effect of A. philippense and chloramphenicol. Lastly, molecular docking studies of identified phytochemicals with adhesin proteins of tested food pathogens, which helps the bacteria in surface attachment and leads to biofilm formation, were assessed. A. philippense crude extract was found to be active against all tested food pathogens, displaying the rapid time-dependent kinetics of bacterial killing. A. philippense crude extract also impedes the biofilm matrix by reducing the total content of exopolysaccharide, and, likewise, the microscopic images revealed a great extent of disruption in the architecture of biofilms. A synergy was observed between A. philippense crude extract and chloramphenicol for E. coli, S. aureus, and P. aeruginosa, whereas an additive effect was observed for S. flexneri. Various bioactive phytochemicals were categorized from A. philippense crude extract using HR-LCMS. The molecular docking of these identified phytochemicals was interrelated with the active site residues of adhesin proteins, IcsA, Sortase A, OprD, EspA, and FimH from S. flexneri, S. aureus, P. aeruginosa, and E. coli, respectively. Thus, our findings represent the bioactivity and potency of A. philippense crude extract against food pathogens not only in their planktonic forms but also against/in biofilms for the first time. We have also correlated these findings with the possible mechanism of biofilm inhibition via targeting adhesin proteins, which could be explored further to design new bioactive compounds against biofilm producing foodborne bacterial pathogens.},
}
@article {pmid32477285,
year = {2020},
author = {Su, T and He, J and Li, N and Liu, S and Xu, S and Gu, L},
title = {A Rational Designed PslG With Normal Biofilm Hydrolysis and Enhanced Resistance to Trypsin-Like Protease Digestion.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {760},
pmid = {32477285},
issn = {1664-302X},
abstract = {A glycosyl hydrolase produced by Pseudomonas aeruginosa, PslG, has become a promising candidate for biofilm treatment because of its ability to inhibit and disperse biofilms by disrupting exopolysaccharide matrix at nanomolar concentrations. However, as a protein, PslG used for treatment may be degraded by the ubiquitous proteases (of which trypsin-like serine proteases are a major group) secreted by human cells. This would lead to an insufficient effective concentration of PslG. Here, based on the result of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and structural analysis, we generate a PslG mutant (K286A/K433S) with greatly enhanced trypsin resistance. This measure raises IC50 (the concentration of trypsin that can degrade 50% of protein in 30 min at 37°C) from 0.028 mg mL-1 of the wild-type PslG to 0.283 mg mL-1 of PslG K286A/K433S . In addition, biofilm inhibition assay shows that PslG K286A/K433S is much more efficient than wild-type PslG in the presence of trypsin. This indicates that PslG K286A/K433S is a better biofilm inhibitor than wild-type PslG in clinical use where trypsin-like proteases widely exist.},
}
@article {pmid32477284,
year = {2020},
author = {Priya, A and Pandian, SK},
title = {Piperine Impedes Biofilm Formation and Hyphal Morphogenesis of Candida albicans.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {756},
pmid = {32477284},
issn = {1664-302X},
abstract = {Candida albicans is the primary etiological agent associated with the pathogenesis of candidiasis. Unrestricted growth of C. albicans in the oral cavity may lead to oral candidiasis, which can progress to systemic infections in worst scenarios. Biofilm of C. albicans encompasses yeast and hyphal forms, where hyphal formation and yeast to hyphal morphological transitions are contemplated as the key virulence elements. Current clinical repercussions necessitate the identification of therapeutic agent that can limit the biofilm formation and escalating the susceptibility of C. albicans to immune system and conventional antifungals. In the present study, a plant-derived alkaloid molecule, piperine, was investigated for the antibiofilm and antihyphal activities against C. albicans. Piperine demonstrated a concentration-dependent antibiofilm activity without exerting negative impact on growth and metabolic activity. Inhibition in the hyphal development was witnessed through confocal laser-scanning microscopy and scanning electron microscopy. Interestingly, piperine displayed a tremendous potential to inhibit the virulence-associated colony morphologies, such as filamentation and wrinkling. Furthermore, piperine regulated morphological transitions between yeast and hyphal forms by inhibiting hyphal extension and swapping hyphal phase to yeast forms yet under filamentation-inducing circumstances. Remarkably, piperine-challenged C. albicans exhibited low potential for spontaneous antibiofilm resistance development. In addition, piperine effectively reduced in vivo colonization and prolonged survival of C. albicans-infected Caenorhabditis elegans, thereby expounding the distinct antivirulent potential. Transcriptomic analysis revealed piperine significantly downregulating the expression of several biofilm related and hyphal-specific genes (ALS3, HWP1, EFG1, CPH1, etc.). Furthermore, no acute toxicity was observed in the HBECs and nematodes exposed to piperine. Altogether, results from this study reveals the potential of piperine to inhibit biofilm and hyphal morphogenesis, and its in vivo efficacy and innocuous nature to HBECs suggests that piperine may be considered as a potential candidate for the treatment of biofilm-associated C. albicans infection, especially for oral candidiasis.},
}
@article {pmid32476070,
year = {2020},
author = {Jeon, DM and An, JS and Lim, BS and Ahn, SJ},
title = {Orthodontic bonding procedures significantly influence biofilm composition.},
journal = {Progress in orthodontics},
volume = {21},
number = {1},
pages = {14},
pmid = {32476070},
issn = {2196-1042},
support = {2017R1A2B4001834//National Research Foundation of Korea/ ; },
mesh = {Animals ; Bacterial Adhesion ; *Biofilms ; Cattle ; Porphyromonas gingivalis ; *Streptococcus mutans ; Surface Properties ; },
abstract = {BACKGROUND: Because changes in surface properties affect bacterial adhesion, orthodontic bonding procedures may significantly influence biofilm formation and composition around orthodontic appliances. However, most studies used a mono-species biofilm model under static conditions, which does not simulate the intraoral environment and complex interactions of oral microflora because the oral cavity is a diverse and changeable environment. In this study, a multi-species biofilm model was used under dynamic culture conditions to assess the effects of the orthodontic bonding procedure on biofilm formation and compositional changes in two main oral pathogens, Streptococcus mutans and Porphyromonas gingivalis.<br><br>METHODS: Four specimens were prepared with bovine incisors and bonding adhesive: untreated enamel surface (BI), enamel surface etched with 37% phosphoric acid (ET), primed enamel surface after etching (PR), and adhesive surface (AD). Surface roughness (SR), surface wettability (SW), and surface texture were evaluated. A multi-species biofilm was developed on each surface and adhesion amounts of Streptococcus mutans, Porphyromonas gingivalis, and total bacteria were analyzed at day 1 and day 4 using real-time polymerase chain reaction. After determining the differences in biofilm formation, SR, and SW between the four surfaces, relationships between bacteria levels and surface properties were analyzed.<br><br>RESULTS: The order of SR was AD < PR < BI < ET, as BI and ET showed more irregular surface texture than PR and AD. For SW, ET had the greatest value followed by PR, BI, and AD. S. mutans and P. gingivalis showed greater adhesion to BI and ET with rougher and more wettable surfaces than to AD with smoother and less wettable surfaces. The adhesion of total bacteria and S. mutans significantly increased over time, but the amount of P. gingivalis decreased. The adhesion amounts of all bacteria were positively correlated with SR and SW, irrespective of incubation time.<br><br>CONCLUSIONS: Within the limitations of this study, changes in SR and SW associated with orthodontic bonding had significant effects on biofilm formation and composition of S. mutans and P. gingivalis.},
}
@article {pmid32474673,
year = {2020},
author = {Liang, J and Liang, D and Liang, Y and He, J and Zuo, S and Zhao, W},
title = {Effects of a derivative of reutericin 6 and gassericin A on the biofilm of Streptococcus mutans in vitro and caries prevention in vivo.},
journal = {Odontology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10266-020-00529-5},
pmid = {32474673},
issn = {1618-1255},
support = {2018B030311047//Guangdong Science and Technology Department/ ; 201804010419//Guangzhou Science, Technology and Innovation Commission/ ; },
abstract = {It is known that Streptococcus mutans (S. mutans) is the leading cariogenic pathogen. Recently, an increasing number of antimicrobial peptides (AMPs) have been brought into consideration as anti-caries agents. Here, we designed and synthesized an AMP derived from reutericin 6 and/or gassericin A, named LN-7, and explored its effect on biofilm of S. mutans UA159 in vitro and development of dental caries in vivo. Antibacterial assays showed that LN-7 was more active against S. mutans (3.2 μM) than many peptide-based agents, capable of killing other types of Streptococci in oral cavity. In addition, LN-7 presented fast killing kinetics, with more than 97% S. mutans killed within 5 min. The mechanism of the antimicrobial activity mainly lies on the disruption of bacterial membrane. Effects of LN-7 on the biofilm formation and the viability of preformed biofilm were quantified by crystal violet staining, which showed that LN-7 could effectively inhibit the biofilm accumulation of S. mutans. Moreover, the biofilm of S. mutans treated with LN-7 displayed notable changes in bacterial viability and morphology, observed by confocal laser scanning microscopy and scanning electron microscopy. In addition, topical oral treatment with LN-7 could suppress the development of dental caries in vivo, reducing the occurrence of severe dental lesion in a rodent model. These results reveal a new peptide-based agent as a topical treatment for dental caries, opening the door to clinical studies to explore its potential for caries prevention.},
}
@article {pmid32474537,
year = {2020},
author = {Eroshenko, DV and Polyudova, TV and Pyankova, AA},
title = {VapBC and MazEF toxin/antitoxin systems in the regulation of biofilm formation and antibiotic tolerance in nontuberculous mycobacteria.},
journal = {International journal of mycobacteriology},
volume = {9},
number = {2},
pages = {156-166},
doi = {10.4103/ijmy.ijmy_61_20},
pmid = {32474537},
issn = {2212-554X},
abstract = {Background: Mycobacterium smegmatis and other nontuberculous mycobacteria (NTM) are widely distributed in the environment, but a significant increase of NTM infections has taken place in the last few decades. The objective of this study was to determine the role of toxin-antitoxin (TA) vapBC and mazEF systems that act as effectors of persistence in the stress response of NTM.<br><br>Methods: The growth ability and the biofilm formation of NTM were evaluated by conventional methods. Bacterial cell viability was determined using MTT staining, agar plating, or the method of limiting dilutions. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of antibiotics were estimated using broth and agar dilution methods.<br><br>Results: Despite a comparable growth dynamics and biofilm formation on solid/liquid interface with the wild type, a M. smegmatis vapBC, mazEF, and vapBC × mazEF deletion mutant produced more abundant pellicle and were more susceptible to heat shock. Significant differences were also found in the resistance wild type of NTM to isoniazid and ciprofloxacin reflected by higher MBC/MIC ratios. The proposed method of cultivation of agar blocks without visible growth after MIC determination into a liquid medium allows us to detect transition of all wild type of NTM strains to a dormant state in the presence of subMICs of isoniazid and ciprofloxacin while all deletion mutants failed to form dormant cells.<br><br>Conclusion: Our data suggest that both vapBC and mazEF TA systems putatively involved in the heat and antibiotic stress response of NTM via their key role in transition to the dormant state.},
}
@article {pmid32474228,
year = {2020},
author = {Wagner, EM and Pracser, N and Thalguter, S and Fischel, K and Rammer, N and Pospíšilová, L and Alispahic, M and Wagner, M and Rychli, K},
title = {Identification of biofilm hotspots in a meat processing environment: Detection of spoilage bacteria in multi-species biofilms.},
journal = {International journal of food microbiology},
volume = {328},
number = {},
pages = {108668},
doi = {10.1016/j.ijfoodmicro.2020.108668},
pmid = {32474228},
issn = {1879-3460},
abstract = {Biofilms are comprised of microorganisms embedded in a self-produced matrix that normally adhere to a surface. In the food processing environment they are suggested to be a source of contamination leading to food spoilage or the transmission of food-borne pathogens. To date, research has mainly focused on the presence of (biofilm-forming) bacteria within food processing environments, without measuring the associated biofilm matrix components. Here, we assessed the presence of biofilms within a meat processing environment, processing pork, poultry and beef, by the detection of microorganisms and at least two biofilm matrix components. Sampling included 47 food contact surfaces and 61 non-food contact surfaces from eleven rooms within an Austrian meat processing plant, either during operation or after cleaning and disinfection. The 108 samples were analysed for the presence of microorganisms by cultivation and targeted quantitative real-time PCR based on 16S rRNA. Furthermore, the presence of the major matrix components carbohydrates, extracellular DNA and proteins was evaluated. Overall, we identified ten biofilm hotspots, among them seven of which were sampled during operation and three after cleaning and disinfection. Five biofilms were detected on food contact surfaces (cutters and associated equipment and a screw conveyor) and five on non-food contact surfaces (drains and water hoses) resulting in 9.3 % of the sites being classified as biofilm positive. From these biofilm positive samples, we cultivated bacteria of 29 different genera. The most prevalent bacteria belonged to the genera Brochothrix (present in 80 % of biofilms), Pseudomonas and Psychrobacter (isolated from 70 % biofilms). From each biofilm we isolated bacteria from four to twelve different genera, indicating the presence of multi-species biofilms. This work ultimately determined the presence of multi-species biofilms within the meat processing environment, thereby identifying various sources of potential contamination. Especially the identification of biofilms in water hoses and associated parts highlights the need of a frequent monitoring at these sites. The knowledge gained about the presence and composition of biofilms (i.e. chemical and microbiological) will help to prevent and reduce biofilm formation within food processing environments.},
}
@article {pmid32474216,
year = {2020},
author = {Wang, J and Liu, Q and Dong, D and Hu, H and Wu, B and Ren, H},
title = {In-situ monitoring of the unstable bacterial adhesion process during wastewater biofilm formation: A comprehensive study.},
journal = {Environment international},
volume = {140},
number = {},
pages = {105722},
doi = {10.1016/j.envint.2020.105722},
pmid = {32474216},
issn = {1873-6750},
abstract = {The initial bacterial adhesion phase is a pivotal and unstable step in the formation of biofilms. The initiation of biofilm formation is an unstable process caused by the reversible adhesion of bacteria, which is always time-consuming and yet to be elucidated. In this study, impedance-based real time cell analysis (RTCA) was employed to comprehensively investigate the initial bacterial adhesion process. Results showed that the time required for the unstable adhesion process was significantly (p < 0.05) reduced by increasing the initial concentration of bacteria, which is mainly attributed to the large deposition rate of bacteria at high concentrations. In addition, the unstable adhesion process is also regulated by shear stress, derived in this work from orbital shaking. Shear stress improves the reversibility of unstable bacterial attachment. Furthermore, attachment characteristics during the unstable phase vary between different species of bacteria (Sphingomonas rubra, Nakamurella multipartita and mixed bacteria). The S. rubra strain and mixed culture were more prone to adhere to the substratum surface during the unstable process, which was attributed to the smaller xDLVO energy barrier and motility of species in comparison with N. multipartita. Meanwhile, the molecular composition of extracellular polymeric substances (EPS) in the initial attachment phase presented a significant difference in expressed proteins, indicating the important role of proteins in EPS that strengthen bacterial adhesion. Overall, these findings suggest that during the biofilm reactor start-up process, seed sludge conditions, including the bacterial concentration, composition and hydraulics, need to be carefully considered.},
}
@article {pmid32474215,
year = {2020},
author = {Huyan, J and Tian, Z and Zhang, Y and Zhang, H and Shi, Y and Gillings, MR and Yang, M},
title = {Dynamics of class 1 integrons in aerobic biofilm reactors spiked with antibiotics.},
journal = {Environment international},
volume = {140},
number = {},
pages = {105816},
doi = {10.1016/j.envint.2020.105816},
pmid = {32474215},
issn = {1873-6750},
abstract = {Class 1 integrons are strongly associated with the dissemination of antibiotic resistance in bacteria. However, little is known about whether the presence of antibiotics affects the abundance of integrons and antibiotic resistance genes during biological wastewater treatment. To explore the roles of class 1 integrons in spreading antibiotic resistance genes in environmental compartments, the dynamics of integrons were followed in biofilm reactors treating synthetic wastewater respectively spiked with streptomycin (STM) and oxytetracycline (OTC). The relative abundance of the integron-integrase gene (intI1) increased 12 or 29-fold respectively when treated with STM or OTC, under incrementally increasing dosage regimes from 0 to 50 mg L-1. Significant increases in intI1 abundance initially occurred at an antibiotic dose of 0.1 mg L-1. At the beginning of the experiment, 51% to 64% of integrons carried no gene cassettes. In STM and OTC spiked systems, there was a significant increase in the proportion of integrons that contained resistance gene cassettes, particularly at intermediate and higher antibiotic concentrations. Gene cassettes encoding resistance to aminoglycosides, trimethoprim, beta-lactam, erythromycin, and quaternary ammonium compounds were all detected in the treated systems. Three tetracycline resistance genes (tetA, tetC, tetG) were significantly correlated with the abundance of intI1 (p < 0.01), despite no tet resistance being present as a gene cassette. Genome sequencing of isolates showed synteny between the tet resistance genes and intI1, mediated through linkage to transposable elements including Tn3, IS26 and ISCR3. Class 1 integrons appeared to be under positive selection in the presence of antibiotics, and might have actively acquired new gene cassettes during the experiment.},
}
@article {pmid32474211,
year = {2020},
author = {Zhang, Z and Liu, Y and Lu, M and Lyu, X and Gong, T and Tang, B and Wang, L and Zeng, J and Li, Y},
title = {Rhodiola rosea extract inhibits the biofilm formation and the expression of virulence genes of cariogenic oral pathogen Streptococcus mutans.},
journal = {Archives of oral biology},
volume = {116},
number = {},
pages = {104762},
doi = {10.1016/j.archoralbio.2020.104762},
pmid = {32474211},
issn = {1879-1506},
abstract = {OBJECTIVE: The present study aimed to evaluate the effect of Rhodiola rosea extract (RE) on Streptococcus mutans biofilm formation and the relevant mechanism of its action.<br><br>METHODS: The effect of RE on the biofilm formation and extracellular polysaccharides (EPS) synthesis of S. mutans was assessed by confocal laser scanning microscopy (CLSM), crystal violet staining and CFU counting method. Scanning electron microscopy (SEM) was applied to observe the surface morphology of S. mutans biofilms formed on glass coverslips and dental enamel. To study the relevant mechanism, quantitative real time PCR (qRT-PCR) and zymogram assay were applied to measure the expression of virulence genes and the enzymatic activity of glucosyltransferases (Gtfs) under the treatment of RE. The CCK-8 assay was also performed on macrophages (RAWs) and human oral keratinocytes (HOKs) in order to evaluate its biocompatibility.<br><br>RESULTS: As a result, RE inhibited the biofilm formation and EPS synthesis of S. mutans. RE also suppressed the expression of gtf genes and quorum sensing (QS) system as well as the enzymatic activity of Gtf proteins. Moreover, RE exhibited a good biocompatibility to human cells.<br><br>CONCLUSIONS: This study provides the evidence for RE as a novel anti-biofilm agent for clinical use.},
}
@article {pmid32473427,
year = {2020},
author = {Xiong, F and Zhao, X and Wen, D and Li, Q},
title = {Effects of N-acyl-homoserine lactones-based quorum sensing on biofilm formation, sludge characteristics, and bacterial community during the start-up of bioaugmented reactors.},
journal = {The Science of the total environment},
volume = {735},
number = {},
pages = {139449},
doi = {10.1016/j.scitotenv.2020.139449},
pmid = {32473427},
issn = {1879-1026},
abstract = {Bioaugmentation is an effective technology for treating wastewater containing recalcitrant organic pollutants. However, it is restricted by several technical problems, including the difficult colonization and survival of the inoculated bacteria, and the time-consuming start-up process. Considering the important roles of quorum sensing (QS) in regulating microbial behaviors, this study investigated the effects of N-acyl-homoserine lactones (AHLs)-based manipulation on the start-up of biofilm reactors bioaugmented with a pyridine-degrading strain Paracoccus sp. BW001. The results showed that, in the presence of two specific exogenous AHLs (C6-HSL and 3OC6-HSL), the biofilm formation process on carriers was significantly accelerated, producing thick and structured biofilms. The protein and polysaccharide contents of the extracellular polymeric substances (EPS) and soluble microbial products (SMP) in sludge were also elevated, possibly due to the increased abundance of several EPS-producing bacterial genera. Specifically, the stability and complexity of protein structures were improved. Besides the reactor running time, the AHL-manipulation was proved to be the main factor that drove the shift of bacterial community structures in the reactors. The addition of exogenous AHLs significantly increased the succession rate of bacterial communities and decreased the bacterial alpha diversity. Most importantly, the final proportions of the inoculated strain BW001 were elevated by nearly 100% in both sludge and biofilm communities via the AHL-manipulation. These findings strongly elucidated that AHL-based QS was deeply involved in biofilm formation, sludge characteristics, and microbial community construction in bioaugmented reactors, providing a promising start-up strategy for bioaugmentation technology.},
}
@article {pmid32471277,
year = {2020},
author = {Gieroba, B and Krysa, M and Wojtowicz, K and Wiater, A and Pleszczyńska, M and Tomczyk, M and Sroka-Bartnicka, A},
title = {The FT-IR and Raman Spectroscopies as Tools for Biofilm Characterization Created by Cariogenic Streptococci.},
journal = {International journal of molecular sciences},
volume = {21},
number = {11},
pages = {},
pmid = {32471277},
issn = {1422-0067},
support = {LIDER/11/0070/L-8/16/NCBR/2017//National Centre for Research and Development within the Lider VIII/ ; LIDER/11/0070/L-8/16/NCBR/2017//Foundation for Polish Science/ ; },
abstract = {Fourier transform infrared (FT-IR) and Raman spectroscopy and mapping were applied to the analysis of biofilms produced by bacteria of the genus Streptococcus. Bacterial biofilm, also called dental plaque, is the main cause of periodontal disease and tooth decay. It consists of a complex microbial community embedded in an extracellular matrix composed of highly hydrated extracellular polymeric substances and is a combination of salivary and bacterial proteins, lipids, polysaccharides, nucleic acids, and inorganic ions. This study confirms the value of Raman and FT-IR spectroscopies in biology, medicine, and pharmacy as effective tools for bacterial product characterization.},
}
@article {pmid32471210,
year = {2020},
author = {Bossù, M and Selan, L and Artini, M and Relucenti, M and Familiari, G and Papa, R and Vrenna, G and Spigaglia, P and Barbanti, F and Salucci, A and Giorgio, GD and Rau, JV and Polimeni, A},
title = {Characterization of Scardovia wiggsiae Biofilm by Original Scanning Electron Microscopy Protocol.},
journal = {Microorganisms},
volume = {8},
number = {6},
pages = {},
doi = {10.3390/microorganisms8060807},
pmid = {32471210},
issn = {2076-2607},
abstract = {Early childhood caries (ECC) is a severe manifestation of carious pathology with rapid and disruptive progression. The ECC microbiota includes a wide variety of bacterial species, among which is an anaerobic newly named species, Scardovia wiggsiae, a previously unidentified Bifidobacterium. Our aim was to provide the first ultrastructural characterization of S. wiggsiae and its biofilm by scanning electron microscopy (SEM) using a protocol that faithfully preserved the biofilm architecture and allowed an investigation at very high magnifications (order of nanometers) and with the appropriate resolution. To accomplish this task, we analyzed Streptococcusmutans' biofilm by conventional SEM and VP-SEM protocols, in addition, we developed an original procedure, named OsO4-RR-TA-IL, which avoids dehydration, drying and sputter coating. This innovative protocol allowed high-resolution and high-magnification imaging (from 10000× to 35000×) in high-vacuum and high-voltage conditions. After comparing three methods, we chose OsO4-RR-TA-IL to investigate S.wiggsiae. It appeared as a fusiform elongated bacterium, without surface specialization, arranged in clusters and submerged in a rich biofilm matrix, which showed a well-developed micro-canalicular system. Our results provide the basis for the development of innovative strategies to quantify the effects of different treatments, in order to establish the best option to counteract ECC in pediatric patients.},
}
@article {pmid32468379,
year = {2020},
author = {Elsayed, MM and Elgohary, FA and Zakaria, AI and Elkenany, RM and El-Khateeb, AY},
title = {Novel eradication methods for Staphylococcus aureus biofilm in poultry farms and abattoirs using disinfectants loaded onto silver and copper nanoparticles.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-020-09340-9},
pmid = {32468379},
issn = {1614-7499},
abstract = {Recent developments in the nanotechnology field have created opportunities to design new biomaterials for Staphylococcus aureus biofilm eradication. These biomaterials including disinfectant-loaded nanoparticles could overcome the limitations of conventional disinfectants. The objective of this study was to assess the biocidal activity of five commercial disinfectants (DC&amp;R®, VirkonS®, TH4++, Tek-Trol, and peracetic acid) alone and as with silver and copper nanocomposites on S. aureus biofilm at different concentrations and exposure times. Consequently, 227 samples were collected from two broiler farms, two-layer farms, and three abattoirs at El-Dakahlia Province, Egypt, during summer 2018. The samples were collected from birds as well as the surrounding environment. S. aureus strains were isolated and biofilm producers were phenotypically evaluated by Congo red agar (CRA) test. Besides, 4 biofilm-associated genes including bap, fnbA, cna, and ebps were genotypically detected by PCR technology. Out of 227 collected samples, 141 (62.1%) strains were identified as S. aureus, while 127 strains (90.1%) were S. aureus biofilm producers for all examined samples except for hand swabs of abattoir workers. The prevalence of fnbA and bap genes was 79.5% (101/127) and 20.5% (26/127), respectively but, no strains harbored cna or ebps genes. Tested nanocomposites were prepared using an aqueous solution of metal salts such as copper sulfate and silver nitrate and added to the same amount of disinfectant solution. The obtained nanocomposites were characterized by transmission electron microscopy (TEM) and zeta potential which showed spherical and elongated particles and with a surface charge of disinfectants-silver and copper nanocomposites-of 2.92 and 3.43 mV, respectively. Complete eradication of S. aureus biofilm was observed after treatment with disinfectants loaded onto silver (AgNPs) and copper (CuNPs) nanoparticles in varying concentrations as well as at different exposure times in comparing to disinfectants alone. Our results exhibited the potential applications of disinfectant nanocomposites in complete eradication of S. aureus biofilm in farms and abattoirs without developing of disinfectant resistant bacteria.},
}
@article {pmid32466673,
year = {2020},
author = {Sen, CK and Mathew-Steiner, SS and Das, A and Sundaresan, VB and Roy, S},
title = {Electroceutical Management of Bacterial Biofilm and Surgical Infection.},
journal = {Antioxidants &amp; redox signaling},
volume = {},
number = {},
pages = {},
doi = {10.1089/ars.2020.8086},
pmid = {32466673},
issn = {1557-7716},
abstract = {SIGNIFICANCE: In the host-microbe microenvironment, bioelectrical factors influence microbial, host as well as host-microbe interactions. This article discusses relevant mechanistic underpinnings of this novel paradigm. It also addresses how such knowledge may be leveraged to develop novel electroceutical solutions to manage biofilms in the context of surgical infection. Recent Advances: Systematic review and meta-analysis of several hundred wound studies reported a 78.2% prevalence of biofilms in chronic wounds. Biofilm infection is a major cause of delayed wound healing. In the host-microbe microenvironment, bioelectrical factors influence microbial, host as well as host-microbe interactions.<br><br>CRITICAL ISSUES: Rapid biological responses are driven by electrical signals generated by minute currents of ions moving across cell membranes. Bacterial life, growth and function relies on a bioelectrical milieu which when perturbed impairs their ability to form biofilm, a major threat to healthcare. Viral stability depends on electrostatic forces. Weak electrical field strength, otherwise safe for humans, can achieve such benefit. In the host, electric field enhanced keratinocyte migration, bolstered immune defenses, improved mitochondrial function and demonstrated multiple other effects consistent with supporting wound healing. Deeper mechanistic understanding of electrical principles will inform the design of next generation electroceuticals.<br><br>FUTURE DIRECTIONS: This is an opportune moment in time as there is a surge of interest in electroceuticals in medicine. Projected to reach $35.5 billion by 2025, electroceuticals are becoming a cynosure in the global market. WHO reports that more than 50% of surgical site infections can be antibiotic resistant. Electroceuticals offer a serious alternative.},
}
@article {pmid32466464,
year = {2020},
author = {Noumi, E and Merghni, A and Alreshidi, M and Del Campo, R and Adnan, M and Haddad, O and De Feo, V and Snoussi, M},
title = {Phenotypic and Genotypic Characterization with MALDI-TOF-MS Based Identification of Staphylococcus spp. Isolated from Mobile Phones with their Antibiotic Susceptibility, Biofilm Formation, and Adhesion Properties.},
journal = {International journal of environmental research and public health},
volume = {17},
number = {11},
pages = {},
pmid = {32466464},
issn = {1660-4601},
abstract = {Cell phones, smartphones, and tablets are extensively used in social and professional life, so they are frequently exposed to bacteria. The main goal of the present work was to isolate and characterize Staphylococci strains from students' cell phone mobiles. Subsequently, 24 Staphylococci strains were tested against a wide range of antibiotics, for the distribution of some virulence-related genes and their ability to form biofilm. Staphylococcus spp. were cultured from all studied devices on chromogenic medium and identified using the matrix-assisted laser desorption/ionization (MALDI), time-of-flight (TOF) mass spectrometry (MS) technique (MALDI-TOF-MS). The results obtained showed that S.aureus was the dominant species (19 strains, 79.1%), followed by S.warneri (3 strains, 12.5%), and S.haemolyticus (2 strains, 8.3%). Isolated strains showed high percentages of hydrolytic enzymes production, resistance to many tested antibiotics, and 37.5% expressed the mecA gene. The tested strains were highly adhesive to polystyrene and glass and expressed implicated icaA (62.5%) and icaD (66.6%) genes. All Staphylococcus spp. strains tested were found to possess proteases and the α-hemolysin gene. Our results highlighted the importance of mobile phones as a great source of Staphylococcus spp., and these species were found to be resistant to many antibiotics with multiple antibiotic resistance (MAR) index ranging from (0.444) to (0.812). Most of the studied strains are able to form biofilm and expressed many virulence genes. Phylogenetic analysis based on the phenotypic and genetic characters highlighted the phenotypic and genetic heterogeneity of the S.aureus population studied. Further analyses are needed to elucidate the human health risks associated with the identified Staphylococci strains.},
}
@article {pmid32466324,
year = {2020},
author = {Abdel-Aziz, MM and Emam, TM and Raafat, MM},
title = {Hindering of Cariogenic Streptococcus mutans Biofilm by Fatty Acid Array Derived from an Endophytic Arthrographis kalrae Strain.},
journal = {Biomolecules},
volume = {10},
number = {5},
pages = {},
pmid = {32466324},
issn = {2218-273X},
abstract = {Streptococcus mutans has been considered as the major etiological agent of dental caries, mostly due to its arsenal of virulence factors, including strong biofilm formation, exopolysaccharides production, and high acid production. Here, we present the antivirulence activity of fatty acids derived from the endophytic fungus Arthrographis kalrae isolated from Coriandrum sativum against Streptococcus mutans. The chemical composition of the fatty acids was analyzed by gas chromatography-mass spectrometry GC-MS and revealed nine compounds representing 99.6% of fatty acids, where unsaturated and saturated fatty acids formed 93.8% and 5.8 % respectively. Oleic and linoleic acids were the major unsaturated fatty acids. Noteworthy, the fatty acids at the concentration of 31.3 mg L-1 completely inhibited Streptococcus mutans biofilm, and water insoluble extracellular polysaccharide production in both polystyrene plates, and tooth model assay using saliva-coated hydroxyapatite discs. Inhibition of biofilm correlated significantly and positively with the inhibition of water insoluble extracellular polysaccharide (R=1, p <0.0001). Furthermore, Arthrographis kalrae fatty acids at a concentration of 7.8 mg L-1 exhibited acidogenesis-mitigation activity. They did not show bactericidal activity against Streptococcus mutans and cytotoxic activity against human oral fibroblast cells at the concentration used. On the other hand, saliva-coated hydroxyapatite discs treated with sub-minimum biofilm inhibitory concentration of fatty acids showed disturbed biofilm architecture with a few unequally distributed clumped matrices using fluorescence microscopy. Our findings revealed that the intracellular fatty acid arrays derived from endophytic Arthrographis kalrae could contribute to the biofilm-preventing alternatives, specifically Streptococcus mutans biofilms.},
}
@article {pmid32466299,
year = {2020},
author = {Swolana, D and Kępa, M and Idzik, D and Dziedzic, A and Kabała-Dzik, A and Wąsik, TJ and Wojtyczka, RD},
title = {The Antibacterial Effect of Silver Nanoparticles on Staphylococcus epidermidis Strains with Different Biofilm-Forming Ability.},
journal = {Nanomaterials (Basel, Switzerland)},
volume = {10},
number = {5},
pages = {},
pmid = {32466299},
issn = {2079-4991},
support = {KNW-2-K32/D/9/N//Medical University of Silesia/ ; },
abstract = {Among many infectious diseases, infections caused by pathogens of Staphylococcus species exert a substantial influence upon human health, mainly due to their continuous presence on human skin and mucous membranes. For that reason, an intensive search for new, effective anistaphyloccocal agents can currently be observed worldwide. In recent years, there has been growing interest in nanoparticles, as compounds with potential antibacterial effect. The antibacterial activity of silver containing substances has been well recognized, but thoughtful studies focused on the effect of silver nanoparticles on bacterial biofilm are scarce. The aim of this study was to assess the influence of silver nanoparticles (AgNPs) with particle sizes in the range between 10 and 100 nm, and a concentration range from 1 to 10 µg/mL, upon Staphylococcus epidermidis strains with different biofilm-forming abilities (BFAs). The studies revealed the highest level of antimicrobial activity for AgNPs in relation to S. epidermidis strains with BFA, and what is more, the observed effect was proportional to the increasing particles' size, and strains not forming biofilm were more susceptible to silver nanoparticles with the smallest examined size, which was 10 nm.},
}
@article {pmid32466155,
year = {2020},
author = {Staszczyk, M and Jurczak, A and Magacz, M and Kościelniak, D and Gregorczyk-Maga, I and Jamka-Kasprzyk, M and Kępisty, M and Kołodziej, I and Kukurba-Setkowicz, M and Krzyściak, W},
title = {Effect of Polyols and Selected Dental Materials on the Ability to Create a Cariogenic Biofilm-On Children Caries-Associated Streptococcus Mutans Isolates.},
journal = {International journal of environmental research and public health},
volume = {17},
number = {10},
pages = {},
pmid = {32466155},
issn = {1660-4601},
support = {N41/DBS/000163, N41/DBS/000357, N41/DBS/000162//Jagiellonian University Medical College/ ; },
abstract = {Secondary caries is a disease associated with the formation of biofilm on the border of the tooth and dental filling. Its development is strongly influenced by the dietary sweet foods and the type of dental material. The aim of the study was to assess the effect of sweeteners on the ability of clinical Streptococcus mutans strains to form biofilm on dental materials. Strains were isolated from plaque samples from 40 pediatric patients from the 3-6 ICADS II group. The ability to form biofilm was tested on composite and glass ionomer dental materials used for milk teeth filling in the presence of sucrose, xylitol, sorbitol, and erythritol. The bacterial film mass after 12, 24, 48, and 72 h and the number of bacterial colonies significantly decreased (p < 0.01) compared to the initial value for 5% erythritol and sorbitol on examined materials. A greater inhibitory effect was noted for glass ionomers compared to composites. Sucrose and xylitol supported biofilm formation, while erythritol had the best inhibitory effect. The use of fluoride-releasing glass ionomers exerted an effect synergistic to erythritol, i.e., inhibited plaque formation and the amount of cariogenic S. mutans. Selection of proper type of dental material together with replacing sucrose with polyols can significantly decrease risk of secondary caries development. Erithritol in combination with glass ionomer seems to be the most effective in secondary caries prevention.},
}
@article {pmid32466117,
year = {2020},
author = {Iseppi, R and Di Cerbo, A and Aloisi, P and Manelli, M and Pellesi, V and Provenzano, C and Camellini, S and Messi, P and Sabia, C},
title = {In Vitro Activity of Essential Oils Against Planktonic and Biofilm Cells of Extended-Spectrum β-Lactamase (ESBL)/Carbapenamase-Producing Gram-Negative Bacteria Involved in Human Nosocomial Infections.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {9},
number = {5},
pages = {},
pmid = {32466117},
issn = {2079-6382},
abstract = {The aim of this study was to analyze the antibacterial activity of four essential oils (EOs), Melaleuca alternifolia, Eucalyptus globulus, Mentha piperita, and Thymus vulgaris, in preventing the development and spread of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae, metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa and carbapenemase (KPC)-producing Klebsiella pneumoniae. A total of 60 strains were obtained from the stock collection from the Microbiology Laboratory of Hesperia Hospital, Modena, Italy. Twenty ESBL-producing E. coli, 5 K. pneumoniae, 13 KPC-producing K. pneumoniae, and 20 MBL-producing P. aeruginosa were cultured and reconfirmed as ESBL and carbapenamase producers. Polymerase chain reaction was used for the detection of genes responsible for antibiotic resistance (ESBL and KPC/MBL). Antibacterial activity of the EOs was determined using the agar disk diffusion assay, and minimal inhibitory concentrations (MICs) were also evaluated. Lastly, adhesion capability and biofilm formation on polystyrene and glass surfaces were studied in 24 randomly selected strains. M. alternifolia and T. vulgaris EOs showed the best antibacterial activity against all tested strains and, as revealed by agar disk diffusion assay, M. alternifolia was the most effective, even at low concentrations. This effect was also confirmed by MICs, with values ranging from 0.5 to 16 µg/mL and from 1 to 16 µg/mL, for M. alternifolia and T. vulgaris EOs, respectively. The EOs' antibacterial activity compared to antibiotics confirmed M. alternifolia EO as the best antibacterial agent. T. vulgaris EO also showed a good antibacterial activity with MICs lower than both reference antibiotics. Lastly, a significant anti-biofilm activity was observed for the two EOs (*P < 0.05 and **P < 0.01 for M. alternifolia and T. vulgaris EOs, respectively). A good antibacterial and anti-biofilm activity of M. alternifolia and T. vulgaris EOs against all selected strains was observed, thus demonstrating a future possible use of these EOs to treat infections caused by ESBL/carbapenemase-producing strains, even in association with antibiotics.},
}
@article {pmid32464310,
year = {2020},
author = {Santos, FAGD and Leite-Andrade, MC and Brandão, IS and Alves, AIDS and Buonafina, MDS and Nunes, M and Araújo-Neto, LN and Freitas, MA and Brayner, FA and Alves, LC and Coutinho, HDM and Neves, RP},
title = {Anti-biofilm effect by the combined action of fluconazole and acetylsalicylic acid against species of Candida parapsilosis complex.},
journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases},
volume = {84},
number = {},
pages = {104378},
doi = {10.1016/j.meegid.2020.104378},
pmid = {32464310},
issn = {1567-7257},
abstract = {The Candida parapsilosis complex has been associated with highly refractory infections mainly due to the presence of biofilms. High glucose levels enable the development of this virulence factor which can aggravate the clinical condition of patients with diabetes mellitus, those using parenteral nutrition, with invasive medical device, including others. Combined antifungal therapy, such as azole and cyclooxygenase inhibitors, may be an alternative in such infections since they modulate prostaglandin production favoring the adhesion and development of biofilms. Thus, the present study aimed to evaluate the influence of glucose supplementation in the formation and detection of Candida parapsilosis complex biofilms and to treat them using fluconazole and a cyclooxygenase inhibitor in combination. Protein spectra evaluation allowed the differentiation between species from the complex (score > 2) in our studies. All isolates were able to form active biofilms at different glucose concentrations. In addition, a significant reduction in biofilm formation was observed when fluconazole and acetylsalicylic acid were combined. The ultrastructural analysis presented typical biofilm characteristics by species from the complex. These data support new combined therapies for the treatment of fungal infections, especially with those which are resistant and therapeutic failure is associated with virulence factors.},
}
@article {pmid32464303,
year = {2020},
author = {Frassinetti, S and Falleni, A and Del Carratore, R},
title = {Effect of itraconazole on Staphylococcus aureus biofilm and extracellular vesicles formation.},
journal = {Microbial pathogenesis},
volume = {147},
number = {},
pages = {104267},
doi = {10.1016/j.micpath.2020.104267},
pmid = {32464303},
issn = {1096-1208},
abstract = {Staphylococcus aureus is a leading cause of a wide range of clinical chronic infections mainly due to the establishment of a biofilm. Biofilm, a population of bacteria within a self-produced matrix of extracellular polymeric substance, decreases the susceptibility to antibiotics, immune defenses and contributes to antimicrobial resistance. To date antibiotic combination has been considered a strategy to combat S. aureus infection, but this approach does not solves the main pharmacokinetic problem caused by biofilms, consisting in insufficient drug penetration within the structure. Therefore, new antimicrobial agents that could overcome this resistance need to be discovered. Fighting staphylococcal resistance and biofilm formation is an important goal of the pharmaceutical research. Some fungicide has been observed to have antibacterial effect. anyway their use as antibiotics on S.aureus has been poorly studied. The aim of this work was to investigate the effect of the fungicide itraconazole (IT) on S. aureus biofilm formation and explore by SEM the morphological alteration after treatment. A strong biofilm disaggregation and morphologically different extracellular vesicles (EV) production were observed starting from sublethal IT doses. This suggests that IT resistance phenomena on the part of S. aureus are more difficult to establish respect other antibiotics. The adjuvant properties of IT could be used to combat bacterial biofilm and/or to improve antibiotic treatment. Moreover, because the production of EV represents a secretory pathway involved in intercellular communication shared to mammalian cells, fungi, and bacteria, our study is important to increase information that can be generalized to higher organisms.},
}
@article {pmid32464301,
year = {2020},
author = {Okaro, U and George, S and Valdes, S and Macaluso, K and Anderson, B},
title = {A non-coding RNA controls transcription of a gene encoding a DNA binding protein that modulates biofilm development in Bartonella henselae.},
journal = {Microbial pathogenesis},
volume = {147},
number = {},
pages = {104272},
doi = {10.1016/j.micpath.2020.104272},
pmid = {32464301},
issn = {1096-1208},
abstract = {Bartonella henselae (Bh) is a Gram-negative zoonotic bacterium that can grow as large aggregates and form biofilms in vitro dependent upon the adhesin BadA. Previously, we reported that the Houston-1 strain of Bh has a family of nine small, highly-expressed intergenic transcripts called Bartonellaregulatory transcripts, Brt1-9. Each of the Brts bears a stem and loop structure on the 3' end followed by a gene encoding a DNA binding protein called the Transcriptional regulatory proteins, Trp1-9. RNA-seq analysis of laboratory-grown bacteria revealed the trps were poorly transcribed suggesting that the 3' stem and loop on the Brts results in transcript termination upstream of the trp genes under these conditions. Here we demonstrate that transcription of brt1 continues into trp1 when Bh is grown in a biofilm. Deletion of brt1, or just the 3' terminus of brt1 (containing the stem and loop structure), resulted in increased transcription of both trp1 and badA and increased biofilm formation. Trp1 was shown to directly bind the putative badA promoter region as demonstrated by an electrophoretic mobility shift assay (EMSA). Our data suggest that the 3' end of brt1 responds to a stimulus generated by growth of Bh in an in vitro biofilm to allow increased trp1 transcription. We further show that transcription of trp1 increases under conditions consistent with the mammalian host but is not highly expressed in the cat flea vector until the bacterium is excreted into the flea feces. Based on these data, we hypothesize that the 3' end of Brt1 functions to control trp1 transcription and Trp1 in turn results in increased badA expression and enhanced biofilm formation.},
}
@article {pmid32463353,
year = {2020},
author = {Kim, HR and Shin, DS and Jang, HI and Eom, YB},
title = {Anti-biofilm and anti-virulence effects of zerumbone against Acinetobacter baumannii.},
journal = {Microbiology (Reading, England)},
volume = {},
number = {},
pages = {},
doi = {10.1099/mic.0.000930},
pmid = {32463353},
issn = {1465-2080},
abstract = {Acinetobacter baumannii is a multidrug-resistant opportunistic pathogen that affects patients with a compromised immune system and is becoming increasingly important as a hospital-derived infection. This pathogen is difficult to treat owing to its intrinsic multidrug resistance and ability to form antimicrobial-tolerant biofilms. In the present study, we aimed to assess the potential use of zerumbone as a novel anti-biofilm and/or anti-virulence agent against A. baumannii. The results showed that zerumbone at sub-inhibitory doses decreased biofilm formation and disrupted established A. baumannii biofilms. The zerumbone-induced decrease in biofilm formation was dose-dependent based on the results of microtitre plate biofilm assays and confocal laser scanning microscopy. In addition, our data validated the anti-virulence efficacy of zerumbone, wherein it significantly interfered with the motility of A. baumannii. To support these phenotypic results, transcriptional analysis revealed that zerumbone downregulated the expression of biofilm- and virulence-associated genes (adeA, adeB, adeC and bap) in A. baumannii. Overall, our findings suggested that zerumbone might be a promising bioactive agent for the treatment of biofilm- and virulence-related infections caused by multidrug-resistant A. baumannii.},
}
@article {pmid32463024,
year = {2020},
author = {Badar, W and Ullah Khan, MA},
title = {Analytical study of biosynthesised silver nanoparticles against multi-drug resistant biofilm-forming pathogens.},
journal = {IET nanobiotechnology},
volume = {14},
number = {4},
pages = {331-340},
doi = {10.1049/iet-nbt.2019.0287},
pmid = {32463024},
issn = {1751-875X},
abstract = {The emergence of the huge number of multi-drug resistant (MDR) bacteria requires an alternative to the drugs. Silver nanoparticles (AgNPs) are a strong candidate for this due to their bactericidal properties, which can be better concluded by understanding their morphology and chemistry. The study hypothesised that AgNPs synthesised using leaves of Syzygium cumini can be used to treat locally emerging MDRs forming biofilms on indwelling medical devices. Synthesised particles were characterised by methods like UV-visible spectroscopy, X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and Zetasizer. Fourier transform infrared spectroscopy, and high-performance liquid chromatography were used to predict phytochemicals present in the leaves. The shape of particles is revealed to be relatively spherical, with average size to be around 10-100 nm. Phenolic compounds are attributed to the formation of nanoparticles, stability analysis shows particles to be stable, and zeta potential determined the surface charge to be -20.1 mV. Biosynthesised particles are found to possess efficient antibacterial activity MDR bacteria developing biofilms in medical devices; hence, it is concluded that S. cumini based NPs can be used to develop a layer on implant-related medical devices. Toxicity evaluation against A594 cancer cells portrays AgNPs to be potential tumour reduction agents in a concentration-dependent manner.},
}
@article {pmid32462243,
year = {2020},
author = {Cusimano, MG and Ardizzone, F and Nasillo, G and Gallo, M and Sfriso, A and Martino-Chillura, D and Schillaci, D and Baldi, F and Gallo, G},
title = {Biogenic iron-silver nanoparticles inhibit bacterial biofilm formation due to Ag+ release as determined by a novel phycoerythrin-based assay.},
journal = {Applied microbiology and biotechnology},
volume = {104},
number = {14},
pages = {6325-6336},
doi = {10.1007/s00253-020-10686-w},
pmid = {32462243},
issn = {1432-0614},
support = {none//Università di Palermo/ ; none//Università Ca' Foscari di Venezia/ ; },
abstract = {Silver nanoparticles (Ag-NPs) can be considered as a cost-effective alternative to antibiotics. In the presence of Fe(III)-citrate and Ag+, Klebsiella oxytoca DSM 29614 produces biogenic Ag-NPs embedded in its peculiar exopolysaccharide (EPS). K. oxytoca DSM 29614 was cultivated in a defined growth medium-containing citrate (as sole carbon source) and supplemented with Ag+ and either low or high Fe(III) concentration. As inferred from elemental analysis, transmission and scanning electron microscopy, Fourier transform infrared spectrometry and dynamic light scattering, Ag-EPS NPs were produced in both conditions and contained also Fe. The production yield of high-Fe/Ag-EPS NPs was 12 times higher than the production yield of low-Fe/Ag-EPS NPs, confirming the stimulatory effect of iron. However, relative Ag content and Ag+ ion release were higher in low-Fe/Ag-EPS NPs than in high-Fe/Ag-EPS NPs, as revealed by emission-excitation spectra by luminescent spectrometry using a novel ad hoc established phycoerythrin fluorescence-based assay. Interestingly, high and low-Fe/Ag-EPS NPs showed different and growth medium-dependent minimal inhibitory concentrations against Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 15442. In addition, low-Fe/Ag-EPS NPs exert inhibition of staphylococcal and pseudomonal biofilm formation, while high-Fe/Ag-EPS NPs inhibits staphylococcal biofilm formation only. Altogether, these results, highlighting the different capability of Ag+ release, support the idea that Fe/Ag-EPS NPs produced by K. oxytoca DSM 29614 can be considered as promising candidates in the development of specific antibacterial and anti-biofilm agents.Key points • Klebsiella oxytoca DSM 29614 produces bimetal nanoparticles containing Fe and Ag.• Fe concentration in growth medium affects nanoparticle yield and composition.• Phycoerythrin fluorescence-based assay was developed to determine Ag+release.• Antimicrobial efficacy of bimetal nanoparticle parallels Ag+ions release.},
}
@article {pmid32462094,
year = {2020},
author = {Lima, JY and Moreira, C and Nunes Freitas, PN and Olchanheski, LR and Veiga Pileggi, SA and Etto, RM and Staley, C and Sadowsky, MJ and Pileggi, M},
title = {Structuring biofilm communities living in pesticide contaminated water.},
journal = {Heliyon},
volume = {6},
number = {5},
pages = {e03996},
pmid = {32462094},
issn = {2405-8440},
abstract = {The wide use of pesticides in agriculture expose microbiota to stressful conditions that require the development of survival strategies. The bacterial response to many pollutants has not been elucidated in detail, as well as the evolutionary processes that occur to build adapted communities. The purpose of this study was to evaluate the bacterial population structure and adaptation strategies in planktonic and biofilm communities in limited environments, as tanks containing water used for washing herbicide containers. This biodiversity, with high percentage of nonculturable microorganisms, was characterized based on habitat and abiotic parameters using molecular and bioinformatics tools. According to water and wastewater standards, the physicochemical conditions of the tank water were inadequate for survival of the identified bacteria, which had to develop survival strategies in this hostile environment. The biodiversity decreased in the transition from planktonic to biofilm samples, indicating a possible association between genetic drift and selection of individuals that survive under stressful conditions, such as heating in water and the presence of chlorine, fluorine and agrochemicals over a six-month period. The abundance of Enterobacter, Acinetobacter and Pseudomonas in biofilms from water tanks was linked to essential processes, deduced from the genes attributed to these taxonomic units, and related to biofilm formation, structure and membrane transport, quorum sensing and xenobiotic degradation. These characteristics were randomly combined and fixed in the biofilm community. Thus, communities of biofilm bacteria obtained under these environmental conditions serve as interesting models for studying herbicide biodegradation kinetics and the prospects of consortia suitable for use in bioremediation in reservoirs containing herbicide-contaminated wastewater, as biofilters containing biofilm communities capable of degrading herbicides.},
}
@article {pmid32460495,
year = {2020},
author = {Zhang, J and Brown, J and Scurr, D and Bullen, A and MacLellan-Gibson, K and Williams, P and Alexander, MR and Hardie, KR and Gilmore, IS and Rakowska, PD},
title = {Cryo-OrbiSIMS for 3D molecular imaging of a bacterial biofilm in its native state.},
journal = {Analytical chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.analchem.0c01125},
pmid = {32460495},
issn = {1520-6882},
abstract = {Secondary ion mass spectrometry (SIMS) is gaining popularity for molecular imaging in the life-sciences since it is label-free and allows imaging in two and three dimensions. The recent introduction of the OrbiSIMS has significantly improved the utility for biological imaging through combining sub-cellular spatial resolution with high-performance Orbitrap mass spectrometry. SIMS instruments operate in high-vacuum and samples are typically analysed in a freeze-dried state. Consequently, the molecular and structural information may not be well-preserved. We report a method for molecular imaging of biological materials, preserved in a native state, by using an OrbiSIMS instrument, equipped with cryogenic sample handling, and a high-pressure freezing protocol compatible with mass spectrometry. The performance is demonstrated by imaging a challenging sample (>90% water) of a mature Pseudomonas aeruginosa biofilm in its native state. The 3D distribution of quorum sensing signaling molecules, nucleobases and bacterial membrane molecules are revealed with high spatial-resolution and high mass-resolution. We discover that analysis in the frozen-hydrated state yields a 10,000 fold increase in signal intensity for polar molecules, such as amino acid, which has important implications for SIMS imaging of metabolites and pharmaceuticals.},
}
@article {pmid32460269,
year = {2020},
author = {Hillman, KM and Sims, RC},
title = {Struvite formation associated with the microalgae biofilm matrix of a rotating algal biofilm reactor (RABR) during nutrient removal from municipal wastewater.},
journal = {Water science and technology : a journal of the International Association on Water Pollution Research},
volume = {81},
number = {4},
pages = {644-655},
doi = {10.2166/wst.2020.133},
pmid = {32460269},
issn = {0273-1223},
mesh = {Biofilms ; Extracellular Polymeric Substance Matrix ; *Microalgae ; Nutrients ; Phosphates ; Phosphorus ; Struvite ; Waste Disposal, Fluid ; *Waste Water ; },
abstract = {Struvite was observed within the microalgae biofilm matrix of an outdoor, pilot-scale rotating algal biofilm reactor (RABR) designed to remove nitrogen and phosphorus from municipal anaerobic digester filtrate. The bottom layer of cells (2.5-month growth) and two top layers of cells (1-week and 2.5-month growth) were evaluated on east- and west-facing sides of the RABR. Sun orientation and shading effects of upper biofilm layers impacted the species composition and microalgae content of the bottom biofilm layers. Struvite formed within the microalgae biofilm matrix, and a higher struvite content appeared to be correlated with a higher microalgae content. The highest struvite content (expressed as %wt. of total solids) was observed in the east- and west-facing bottom layers of growth and west-facing 1-week growth (5.0%, 4.3%, and 4.1%, respectively). The lowest struvite content was observed in east- and west-facing 2.5-month growth and east-facing 1-week growth (1.1%, 1.5%, and 1.1%, respectively). Despite RABR influent component ion molar ratios with potential for various magnesium and calcium precipitates, microalgae biofilm provided pH and nucleation sites favorable to struvite precipitation. This evaluation is the first in the refereed literature the authors are aware of that reports on the association of struvite formation in the presence of a microalgae biofilm.},
}
@article {pmid32459613,
year = {2020},
author = {Badal, D and Jayarani, AV and Kollaran, MA and Kumar, A and Singh, V},
title = {Pseudomonas aeruginosa biofilm formation on endotracheal tubes requires multiple two-component systems.},
journal = {Journal of medical microbiology},
volume = {69},
number = {6},
pages = {906-919},
doi = {10.1099/jmm.0.001199},
pmid = {32459613},
issn = {1473-5644},
abstract = {Introduction. Indwelling medical devices such as endotracheal tubes (ETTs), urinary catheters, vascular access devices, tracheostomies and feeding tubes are often associated with hospital-acquired infections. Bacterial biofilm formed on the ETTs in intubated patients is a significant risk factor associated with ventilator-associated pneumonia. Pseudomonas aeruginosa is one of the four frequently encountered bacteria responsible for causing pneumonia, and the biofilm formation on ETTs. However, understanding of biofilm formation on ETT and interventions to prevent biofilm remains lagging. The ability to sense and adapt to external cues contributes to their success. Thus, the biofilm formation is likely to be influenced by the two-component systems (TCSs) that are composed of a membrane-associated sensor kinase and an intracellular response regulator.Aim. This study aims to establish an in vitro method to analyse the P. aeruginosa biofilm formation on ETTs, and identify the TCSs that contribute to this process.Methodology. In total, 112 P. aeruginosa PA14 TCS mutants were tested for their ability to form biofilm on ETTs, their effect on quorum sensing (QS) and motility.Results. Out of 112 TCS mutants studied, 56 had altered biofilm biomass on ETTs. Although the biofilm formation on ETTs is QS-dependent, none of the 56 loci controlled quorum signal. Of these, 18 novel TCSs specific to ETT biofilm were identified, namely, AauS, AgtS, ColR, CopS, CprR, NasT, KdpD, ParS, PmrB, PprA, PvrS, RcsC, PA14_11120, PA14_32580, PA14_45880, PA14_49420, PA14_52240, PA14_70790. The set of 56 included the GacS network, TCS proteins involved in fimbriae synthesis, TCS proteins involved in antimicrobial peptide resistance, and surface-sensing. Additionally, several of the TCS-encoding genes involved in biofilm formation on ETTs were found to be linked to flagellum-dependent swimming motility.Conclusions. Our study established an in vitro method for studying P. aeruginosa biofilm formation on the ETT surfaces. We also identified novel ETT-specific TCSs that could serve as targets to prevent biofilm formation on indwelling devices frequently used in clinical settings.},
}
@article {pmid32457749,
year = {2020},
author = {Parducho, KR and Beadell, B and Ybarra, TK and Bush, M and Escalera, E and Trejos, AT and Chieng, A and Mendez, M and Anderson, C and Park, H and Wang, Y and Lu, W and Porter, E},
title = {The Antimicrobial Peptide Human Beta-Defensin 2 Inhibits Biofilm Production of Pseudomonas aeruginosa Without Compromising Metabolic Activity.},
journal = {Frontiers in immunology},
volume = {11},
number = {},
pages = {805},
pmid = {32457749},
issn = {1664-3224},
abstract = {Biofilm production is a key virulence factor that facilitates bacterial colonization on host surfaces and is regulated by complex pathways, including quorum sensing, that also control pigment production, among others. To limit colonization, epithelial cells, as part of the first line of defense, utilize a variety of antimicrobial peptides (AMPs) including defensins. Pore formation is the best investigated mechanism for the bactericidal activity of AMPs. Considering the induction of human beta-defensin 2 (HBD2) secretion to the epithelial surface in response to bacteria and the importance of biofilm in microbial infection, we hypothesized that HBD2 has biofilm inhibitory activity. We assessed the viability and biofilm formation of a pyorubin-producing Pseudomonas aeruginosa strain in the presence and absence of HBD2 in comparison to the highly bactericidal HBD3. At nanomolar concentrations, HBD2 - independent of its chiral state - significantly reduced biofilm formation but not metabolic activity, unlike HBD3, which reduced biofilm and metabolic activity to the same degree. A similar discrepancy between biofilm inhibition and maintenance of metabolic activity was also observed in HBD2 treated Acinetobacter baumannii, another Gram-negative bacterium. There was no evidence for HBD2 interference with the regulation of biofilm production. The expression of biofilm-related genes and the extracellular accumulation of pyorubin pigment, another quorum sensing controlled product, did not differ significantly between HBD2 treated and control bacteria, and in silico modeling did not support direct binding of HBD2 to quorum sensing molecules. However, alterations in the outer membrane protein profile accompanied by surface topology changes, documented by atomic force microscopy, was observed after HBD2 treatment. This suggests that HBD2 induces structural changes that interfere with the transport of biofilm precursors into the extracellular space. Taken together, these data support a novel mechanism of biofilm inhibition by nanomolar concentrations of HBD2 that is independent of biofilm regulatory pathways.},
}
@article {pmid32457724,
year = {2020},
author = {Aqawi, M and Gallily, R and Sionov, RV and Zaks, B and Friedman, M and Steinberg, D},
title = {Cannabigerol Prevents Quorum Sensing and Biofilm Formation of Vibrio harveyi.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {858},
pmid = {32457724},
issn = {1664-302X},
abstract = {Cannabigerol (CBG) is a non-psychoactive cannabinoid naturally present in trace amounts in the Cannabis plant. So far, CBG has been shown to exert diverse activities in eukaryotes. However, much less is known about its effects on prokaryotes. In this study, we investigated the potential role of CBG as an anti-biofilm and anti-quorum sensing agent against Vibrio harveyi. Quorum sensing (QS) is a cell-to-cell communication system among bacteria that involves small signaling molecules called autoinducers, enabling bacteria to sense the surrounding environment. The autoinducers cause alterations in gene expression and induce bioluminescence, pigment production, motility and biofilm formation. The effect of CBG was tested on V. harveyi grown under planktonic and biofilm conditions. CBG reduced the QS-regulated bioluminescence and biofilm formation of V. harveyi at concentrations not affecting the planktonic bacterial growth. CBG also reduced the motility of V. harveyi in a dose-dependent manner. We further observed that CBG increased LuxO expression and activity, with a concomitant 80% downregulation of the LuxR gene. Exogenous addition of autoinducers could not overcome the QS-inhibitory effect of CBG, suggesting that CBG interferes with the transmission of the autoinducer signals. In conclusion, our study shows that CBG is a potential anti-biofilm agent via inhibition of the QS cascade.},
}
@article {pmid32457717,
year = {2020},
author = {Silva, AV and Edel, M and Gescher, J and Paquete, CM},
title = {Exploring the Effects of bolA in Biofilm Formation and Current Generation by Shewanella oneidensis MR-1.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {815},
pmid = {32457717},
issn = {1664-302X},
abstract = {Microbial electrochemical technologies (METs) have emerged in recent years as a promising alternative green source of energy, with microbes consuming organic matter to produce energy or valuable byproducts. It is the ability of performing extracellular electron transfer that allows these microbes to exchange electrons with an electrode in these systems. The low levels of current achieved have been the limiting factor for the large-scale application of METs. Shewanella oneidensis MR-1 is one of the most studied electroactive organisms regarding extracellular electron transfer, and it has been shown that biofilm formation is a key factor for current generation. The transcription factor bolA has been identified as a central player in biofilm formation in other organisms, with its overexpression leading to increased biofilm. In this work we explore the effect of this gene in biofilm formation and current production by S. oneidensis MR-1. Our results demonstrate that an increased biofilm formation and consequent current generation was achieved by the overexpression of this gene. This information is crucial to optimize electroactive organisms toward their practical application in METs.},
}
@article {pmid32456668,
year = {2020},
author = {Akinpelu, S and Ajayi, A and Smith, SI and Adeleye, AI},
title = {Efflux pump activity, biofilm formation and antibiotic resistance profile of Klebsiella spp. isolated from clinical samples at Lagos University Teaching Hospital.},
journal = {BMC research notes},
volume = {13},
number = {1},
pages = {258},
pmid = {32456668},
issn = {1756-0500},
abstract = {OBJECTIVE: Nosocomial and community acquired multidrug resistant Klebsiella infections are wide spread resulting in high morbidity and mortality due to limited number of antibiotics treatment options. This study investigated efflux pump activity, biofilm forming potential and antibiotic susceptibility profile of Klebsiella spp. isolated from clinical samples in a tertiary hospital in Lagos Nigeria. Eighteen clinical Klebsiella spp. isolated from urine, blood and sputum were subjected to antibiotic susceptibility testing using the disc diffusion method. Efflux pump activity was evaluated by the ethidium bromide cartwheel method and biofilm forming ability was determined by the tissue culture plate technique.<br><br>RESULTS: All 18 (100%) Klebsiella isolates were resistant to cefuroxime, cefixime, amoxicillin - clavulanate, ampicillin + cloxacillin, cefotaxime, and imipenem. Seventeen (94.4%) were resistant to ofloxacin while sixteen (88.9%) were resistance to nalidixic acid, Gentamicin and levofloxacin. All Klebsiella isolates possessed active efflux pump with the ability to form biofilm. However, their biofilm forming capabilities varied as 4 (22.2%) were strong, 3 (16.7%) were moderate and 11 (61.1%) were weak biofilm formers. Findings in this study reveal multiple factors at play in mediating the high level of antibiotic resistance observed in Klebsiella isolates. Hence a multifaceted approach is advocated in managing the infections caused by the pathogen.},
}
@article {pmid32455691,
year = {2020},
author = {Teul, J and Deja, S and Celińska-Janowicz, K and Ząbek, A and Młynarz, P and Barć, P and Junka, A and Smutnicka, D and Bartoszewicz, M and Pałka, J and Miltyk, W},
title = {LC-QTOF-MS and 1H NMR Metabolomics Verifies Potential Use of Greater Omentum for Klebsiella pneumoniae Biofilm Eradication in Rats.},
journal = {Pathogens (Basel, Switzerland)},
volume = {9},
number = {5},
pages = {},
pmid = {32455691},
issn = {2076-0817},
support = {DEC-2012/07/N/NZ4/02528//National Science Centre in Poland/ ; },
abstract = {Bacterial wound infections are a common problem associated with surgical interventions. In particular, biofilm-forming bacteria are hard to eradicate, and alternative methods of treatment based on covering wounds with vascularized flaps of tissue are being developed. The greater omentum is a complex organ covering the intestines in the abdomen, which support wound recovery following surgical procedures and exhibit natural antimicrobial activity that could improve biofilm eradication. We investigated changes in rats' metabolome following Klebsiella pneumoniae infections, as well as the greater omentum's ability for Klebsiella pneumoniae biofilm eradication. Rats received either sterile implants or implants covered with Klebsiella pneumoniae biofilm (placed in the peritoneum or greater omentum). Metabolic profiles were monitored at days 0, 2, and 5 after surgery using combined proton nuclear magnetic resonance (1H NMR) and high performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (LC-QTOF‑MS) measurements of urine samples followed by chemometric analysis. Obtained results indicated that grafting of the sterile implant to the greater omentum did not cause major disturbances in rats' metabolism, whereas the sterile implant located in the peritoneum triggered metabolic perturbations related to tricarboxylic acid (TCA) cycle, as well as choline, tryptophan, and hippurate metabolism. Presence of implants colonized with Klebsiella pneumoniae biofilm resulted in similar levels of metabolic perturbations in both locations. Our findings confirmed that surgical procedures utilizing the greater omentum may have a practical use in wound healing and tissue regeneration in the future.},
}
@article {pmid32455536,
year = {2020},
author = {Ferriol-González, C and Domingo-Calap, P},
title = {Phages for Biofilm Removal.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {9},
number = {5},
pages = {},
pmid = {32455536},
issn = {2079-6382},
support = {20200063//European Society of Clinical Microbiology and Infectious Diseases/ ; 724519/ERC_/European Research Council/International ; },
abstract = {Biofilms are clusters of bacteria that live in association with surfaces. Their main characteristic is that the bacteria inside the biofilms are attached to other bacterial cells and to the surface by an extracellular polymeric matrix. Biofilms are capable of adhering to a wide variety of surfaces, both biotic and abiotic, including human tissues, medical devices, and other materials. On these surfaces, biofilms represent a major threat causing infectious diseases and economic losses. In addition, current antibiotics and common disinfectants have shown limited ability to remove biofilms adequately, and phage-based treatments are proposed as promising alternatives for biofilm eradication. This review analyzes the main advantages and challenges that phages can offer for the elimination of biofilms, as well as the most important factors to be taken into account in order to design effective phage-based treatments.},
}
@article {pmid32454957,
year = {2020},
author = {Sapata, DM and Ramos, AL and Sábio, S and Normando, D and Pascotto, RC},
title = {Evaluation of biofilm accumulation on and deactivation force of orthodontic Ni-Ti archwires before and after exposure to an oral medium: A prospective clinical study.},
journal = {Journal of dental research, dental clinics, dental prospects},
volume = {14},
number = {1},
pages = {41-47},
pmid = {32454957},
issn = {2008-210X},
abstract = {Background. This in vitro study aimed to evaluate biofilm accumulation on and deactivation force of orthodontic nickeltitanium (NiTi) archwires before and after exposure to an oral medium. Methods. Four commercial brands of orthodontic NiTi 0.016&quot; archwires were examined before and after exposure to the oral medium for 4 weeks. Six archwire segments, 30 mm in length, from each manufacturer were tested in a device with four selfligating brackets, channel 0.022&quot;, adapted to a universal test machine to evaluate the deactivation force between 0.5 and 3 mm of deflection. The presence of biofilm on the archwire surfaces was evaluated by scanning electron microscopy, before and after exposure to the oral medium. The Wilcoxon and kappa tests were applied to the biofilm scores, three-way ANOVA for repeated measures (Bonferroni post-test), and linear regression between biofilm and deactivation force. Results. The exposure to the oral medium promoted moderate to severe presence of debris on the archwire surfaces and caused a reduction in deactivation force for the Ormco and GAC brands, while maintaining them with adequate force levels. The MORELLI and ORTHOMETRIC archwires underwent no significant reduction in deactivation force; moreover, these maintained elevated levels of force after exposure to the oral medium. The Spearman test indicated a low correlation between biofilm accumulation and deflection force for the Morelli (R2=0.132 and P=0.683) and Orthometric (R2=0.308 and P=0.330) brands. On the other hand, the GAC (R=0.767 and P=0.004) and ORMCO (R=0.725 and P=0.008) brands exhibited statistically significant correlation between these variables. Conclusion. Exposure to the oral medium for one month might give rise to significant changes in the dissipation of forces of orthodontic NiTi archwires, resulting from biofilm accumulation.},
}
@article {pmid32454735,
year = {2019},
author = {Kart, D and Kuştimur, AS},
title = {Investigation of Gelatinase Gene Expression and Growth of Enterococcus faecalis Clinical Isolates in Biofilm Models.},
journal = {Turkish journal of pharmaceutical sciences},
volume = {16},
number = {3},
pages = {356-361},
pmid = {32454735},
issn = {2148-6247},
abstract = {Objectives: Enterococcus faecalis is the major reason for biofilm-related infections and it also interacts with Staphylococcus aureus in biofilms. Gelatinase (gelE) enzyme is an important virulence factor of E. faecalis for biofilm formation. This study aimed to compare the biofilm producing E. faecalis isolates from urine and urinary catheters. The influence of S. aureus on the growth of E. faecalis biofilm cells was also investigated in a dual biofilm model in vitro. Another aim was to evaluate E. faecalis gelE gene expression during biofilm formation.<br><br>Materials and Methods: Firstly, crystal violet staining was used to measure the total biofilm biomass of the isolates. Secondly, plate counting was performed to determine the biofilm formation ability of E. faecalis isolates and the effect of S. aureus on E. faecalis biofilm formation. Finally, the gelE expression profile of the isolates was assessed by quantitative real time-polymerase chain reaction.<br><br>Results: According to crystal violet staining and plate counting, all E. faecalis isolates were biofilm producers and the number of E. faecalis sessile cells increased in the presence of S. aureus. Among the 21 E. faecalis isolates, ten expressed high levels of the gelE gene, while eight of them had low expression profiles (p<0.05).<br><br>Conclusion: When they grow together, S. aureus may give some advantages to E. faecalis such as increasing sessile cell growth. The expression of the gelE gene was not affected by E. faecalis biofilm formation of the isolates collected from the patients with urinary tract infections.},
}
@article {pmid32454336,
year = {2020},
author = {Zakaria, BS and Dhar, BR},
title = {Changes in syntrophic microbial communities, EPS matrix, and gene-expression patterns in biofilm anode in response to silver nanoparticles exposure.},
journal = {The Science of the total environment},
volume = {734},
number = {},
pages = {139395},
doi = {10.1016/j.scitotenv.2020.139395},
pmid = {32454336},
issn = {1879-1026},
mesh = {Biofilms ; Electrodes ; Extracellular Polymeric Substance Matrix ; *Metal Nanoparticles ; *Microbiota ; Silver ; },
abstract = {Understanding the toxic effect of silver nanoparticles (AgNPs) on various biological wastewater treatment systems is of significant interest to researchers. In recent years, microbial electrochemical technologies have opened up new opportunities for bioenergy and chemicals production from organic wastewater. However, the effects of AgNPs on microbial electrochemical systems are yet to be understood fully. Notably, no studies have investigated the impact of AgNPs on a microbial electrochemical system fed with a complex fermentable substrate. Here, we investigated the impact of AgNPs (50 mg/L) exposure to a biofilm anode in a microbial electrolysis cell (MEC) fed with glucose. The volumetric current density was 29 ± 2.0 A/m3 before the AgNPs exposure, which decreased to 20 ± 2.2 A/m3 after AgNPs exposure. The biofilms produced more extracellular polymeric substances (EPS) to cope with the AgNPs exposure, while carbohydrate to protein ratio in EPS considerably increased from 0.4 to 0.7. Scanning electron microscope (SEM) imaging also confirmed the marked excretion of EPS, forming a thick layer covering the anode biofilms after AgNPs injection. Transmission electron microscope (TEM) imaging showed that AgNPs still penetrated some microbial cells, which could explain the deterioration of MEC performance after AgNPs exposure. The relative expression level of the quorum signalling gene (LuxR) increased by 30%. Microbial community analyses suggested that various fermentative bacterial species (e.g., Bacteroides, Synergistaceae_vadinCA02, Dysgonomonas, etc.) were susceptible to AgNPs toxicity, which led to the disruption of their syntrophic partnership with electroactive bacteria. The abundance of some specific electroactive bacteria (e.g., Geobacter species) also decreased. Moreover, decreased relative expressions of various extracellular electron transfer associated genes (omcB, omcC, omcE, omcZ, omcS, and pilA) were observed. However, the members of family Enterobacteriaceae, known to perform a dual function of fermentation and anodic respiration, became dominant after biofilm anode exposed to AgNPs. Thus, EPS extraction provided partial protection against AgNPs exposure.},
}
@article {pmid32454294,
year = {2020},
author = {Baattrup-Pedersen, A and Graeber, D and Kallestrup, H and Guo, K and Rasmussen, JJ and Larsen, SE and Riis, T},
title = {Effects of low flow and co-occurring stressors on structural and functional characteristics of the benthic biofilm in small streams.},
journal = {The Science of the total environment},
volume = {733},
number = {},
pages = {139331},
doi = {10.1016/j.scitotenv.2020.139331},
pmid = {32454294},
issn = {1879-1026},
abstract = {Low flow and co-occurring stress is a more and more frequent phenomenon these years in small agricultural streams as a consequence of climate change. In the present study we explored short and longer term structural responses of the stream benthic algae community and biofilm metabolism to multiple stress in small streams applying a semi-experimental approach. We hypothesized that i) a reduction in flow in combination with secondary stress (nutrients and sediments) have immediate effects on the benthic algae community in terms of biomass (chlorophyll a, biovolume), taxonomic and trait (lifeform and size distribution) compositions as well as on metabolism (GPP and CR), and ii) that changes in the benthic algae community persist due to altered environmental settings but that functional redundancy among benthic algae species provides a high level of resilience in metabolism (GPP and CR). Overall, we found that stress imposed by nutrients was less pronounced than stress imposed by fine sediments under low flow, and that nutrient enrichment to some extent mitigated effects of fine sediments. Fine sediment deposition mediated a decline in the fraction of erect algae and/or algae with mucilage stalks but this did not happen under co-occurring stress from both sediments and nutrients. Additionally, fine sediment deposition mediated a decline in GPP of the biofilm, but again this did not happen under co-occurring stress from nutrients. We conclude that 1) the benthic algae community and biofilm metabolism displayed similar resilience to stress imposed by low flow and co-occurring stress from nutrients and sediments on a short and longer time scale and 2) as structure-function adaptations may occur at several trophic levels in the biofilm, more research is needed to explore mechanisms underlying mitigating effects of nutrients in response to sediment deposition under low flow.},
}
@article {pmid32452215,
year = {2020},
author = {Badi, S and Salah Abbassi, M and Snoussi, M and Werheni, R and Hammami, S and Maal-Bared, R and Hassen, A},
title = {High rates of antibiotic resistance and biofilm production in Escherichia coli isolates from food products of animal and vegetable origins in Tunisia: a real threat to human health.},
journal = {International journal of environmental health research},
volume = {},
number = {},
pages = {1-11},
doi = {10.1080/09603123.2020.1769039},
pmid = {32452215},
issn = {1369-1619},
abstract = {The aim of this study was to compare the antibiotic susceptibility of eighty Escherichia coli isolates from vegetables and food products of animal origin in Tunisia, and to study their genes encoding antibiotic resistance and in vitro biofilm forming capacity. Antimicrobial susceptibilities were determined, as well as PCR investigation of genes associated with antibiotic resistance. Biofilm formation was tested using four different methods: the microtiter plate-, MTT-staining-, XTT-staining-, and the Congo Red Agar assays. High antibiotic resistance rates were observed for amoxicillin (68.7%), amoxicillin/clavulanic acid (73.7%), gentamicin (68.7%), kanamycin (66.2%), nalidixic acid (36.2%), streptomycin (68.7%) and tetracycline (35%). The majority of isolates was multidrug resistant and biofilm producer. MTT testing showed that vegetables isolates were significantly higher biofilm producers compared to foods of animal origins. This study showed that E. coli isolates from food products were reservoirs of genes encoding antibiotic-resistance and have a high propensity to produce biofilm.},
}
@article {pmid32451882,
year = {2020},
author = {Li, M and Shi, D and Li, Y and Xiao, Y and Chen, M and Chen, L and Du, H and Zhang, W},
title = {Recombination of T4-like Phages and Its Activity against Pathogenic Escherichia coli in Planktonic and Biofilm Forms.},
journal = {Virologica Sinica},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12250-020-00233-2},
pmid = {32451882},
issn = {1995-820X},
abstract = {The increasing emergence of multi-drug resistant Escherichia coli (E. coli) has become a global concern, primarily due to the limitation of antimicrobial treatment options. Phage therapy has been considered as a promising alternative for treating infections caused by multi-drug resistant E. coli. However, the application of phages as a promising antimicrobial agent is limited by their narrow host range and specificity. In this research, a recombinant T4-like phage, named WGqlae, has been obtained by changing the receptor specificity determinant region of gene 37, using a homologous recombination platform of T4-like phages established by our laboratory previously. The engineered phage WGqlae can lyse four additional hosts, comparing to its parental phages WG01 and QL01. WGqlae showed similar characteristics, including thermo and pH stability, optimal multiplicity of infection and one-step growth curve, to the donor phage QL01. In addition, sequencing results showed that gene 37 of recombinant phage WGqlae had genetically stable even after 20 generations. In planktonic test, phage WGqlae had significant antimicrobial effects on E. coli DE192 and DE205B. The optical density at 600 nm (OD600) of E. coli in phage WGqlae treating group was significantly lower than that of the control group (P < 0.01). Besides, phage WGqlae demonstrated an obvious inhibitory effect on the biofilm formation and the clearance of mature biofilms. Our study suggested that engineered phages may be promising candidates for future phage therapy applications against pathogenic E. coli in planktonic and biofilm forms.},
}
@article {pmid32451587,
year = {2020},
author = {Vishwakarma, J and V L, S},
title = {Unraveling the anti-biofilm potential of green algal sulfated polysaccharides against Salmonella enterica and Vibrio harveyi.},
journal = {Applied microbiology and biotechnology},
volume = {104},
number = {14},
pages = {6299-6314},
doi = {10.1007/s00253-020-10653-5},
pmid = {32451587},
issn = {1432-0614},
abstract = {One of the main reasons for the bacterial resistance to antibiotics is caused by biofilm formation of microbial pathogens during bacterial infections. Salmonella enterica and Vibrio harveyi are known to form biofilms and represent a major health concern worldwide, causing human infections responsible for morbidity and mortality. The current study aims to investigate the effect of purified sulfated polysaccharides (SPs) from Chlamydomonas reinhardtii (Cr) on planktonic and biofilm growth of these bacteria. The effect of Cr-SPs on bacterial planktonic growth was assessed by using the agar well diffusion method, which showed clear zones ranging from 13 to 26 mm in diameter from 0.5 to 8 mg/mL of Cr-SPs against both the bacteria. Time-kill activity and reduction in clonogenic propagation further help to understand the anti-microbial potential of Cr-SPs. The minimum inhibitory concentration of Cr-SPs against S. enterica and V. harveyi was as low as 440 μg/mL and 490 μg/mL respectively. Cr-SPs inhibited bacterial cell attachment up to 34.65-100% at 0.5-8 mg/mL in S. enterica and V. harveyi respectively. Cr-SPs also showed 2-fold decrease in the cell surface hydrophobicity, indicating their potential to prevent bacterial adherence. Interestingly, Cr-SPs efficiently eradicated the preformed biofilms. Increased reduction in total extracellular polysaccharide (EPS) and extracellular DNA (eDNA) content in a dose-dependent manner demonstrates Cr-SPs ability to interact and destroy the bacterial EPS layer. SEM analysis showed that Cr-SPs effectively distorted preformed biofilms and also induced morphological changes. Furthermore, Cr-SPs also showed anti-quorum-sensing potential by reducing bacterial urease and protease activities. These results indicate the potential of Cr-SPs as an anti-biofilm agent and will help to develop them as alternative therapeutics against biofilm-forming bacterial infections. KEY POINTS: • Cr-SPs not only inhibited biofilm formation but also eradicated preformed biofilms. • Cr-SPs altered bacterial cell surface hydrophobicity preventing biofilm formation. • Cr-SPs efficiently degraded eDNA of the EPS layer disrupting mature biofilms. • Cr-SPs reduced activity of quorum-sensing-mediated enzymes like protease and urease.},
}
@article {pmid32450528,
year = {2020},
author = {Zhang, L and Liang, E and Cheng, Y and Mahmood, T and Ge, F and Zhou, K and Bao, M and Lv, L and Li, L and Yi, J and Lu, C and Tan, Y},
title = {Is combined medication with natural medicine a promising therapy for bacterial biofilm infection?.},
journal = {Biomedicine &amp; pharmacotherapy = Biomedecine &amp; pharmacotherapie},
volume = {128},
number = {},
pages = {110184},
doi = {10.1016/j.biopha.2020.110184},
pmid = {32450528},
issn = {1950-6007},
abstract = {Bacterial biofilms widely exist in nature and seriously threaten global public health. Biofilms always cause persistent infection and seriously aggravate the occurrence of antibiotic resistance, which makes the treatment of bacterial infection difficult. Current conventional therapies, such as antibiotics, bacteriophages and quorum sensing inhibitors, are widely used to combat biofilms. However, these therapies are inadequate for the safe and effective treatment of biofilms. Antibiotics often produce resistance in treated bacteria, and antibacterial peptides are easily decomposed by proteases, so their efficacy is reduced. These results indicate that the treatment of biofilms needs further improvement. Increasing evidence has shown that natural medicine therapies have significant inhibitory effects on biofilms. This review summarized and analyzed the efficacy characteristics and corresponding mechanisms of conventional and natural medicine therapies combatting biofilms. By comparison, the advantages and disadvantages of those therapies have been classified and interpreted, so we have inferred that combined medication with natural medicines will be a more effective strategy against biofilms. This review lays a promising foundation for the development of antibiofilm agents and provides novel thinking for the treatment of bacterial biofilm infections.},
}
@article {pmid32450425,
year = {2020},
author = {Zhou, X and Ahmad, JI and van der Hoek, JP and Zhang, K},
title = {Thermal energy recovery from chlorinated drinking water distribution systems: Effect on chlorine and microbial water and biofilm characteristics.},
journal = {Environmental research},
volume = {187},
number = {},
pages = {109655},
doi = {10.1016/j.envres.2020.109655},
pmid = {32450425},
issn = {1096-0953},
abstract = {Thermal energy recovery from drinking water has a high potential in the application of sustainable building and industrial cooling. However, drinking water and biofilm microbial qualities should be concerned because the elevated water temperature after cold recovery may influence the microbial activities in water and biofilm phases in drinking water distribution systems (DWDSs). In this study, the effect of cold recovery on microbial qualities was investigated in a chlorinated DWDS. The chlorine decay was slight (1.1%-15.5%) due to a short contact time (~60 s) and was not affected by the cold recovery (p > 0.05). The concentrations of cellular ATP and intact cell numbers in the bulk water were partially inactivated by the residual chlorine, with the removal rates of 10.1%-16.2% and 22.4%-29.4%, respectively. The chlorine inactivation was probably promoted by heat exchangers but was not further enhanced by higher temperatures. The higher water temperature (25 °C) enhanced the growth of biofilm biomass on pipelines. Principle coordination analysis (PCoA) showed that the biofilms on the stainless steel plates of HEs and the plastic pipe inner surfaces had totally different community compositions. Elevated temperatures favored the growth of Pseudomonas spp. and Legionella spp. in the biofilm after cold recovery. The community functional predictions revealed more abundances of five human diseases (e.g. Staphylococcis aureus infection) and beta-lactam resistance pathways in the biofilms at higher temperature. Compared with a previous study with a non-chlorinated DWDS, chlorine dramatically reduced the biofilm biomass growth but raised the relative abundances of the chlorine-resistant genera (i.e. Pseudomonas and Sphingomonas) in bacterial communities.},
}
@article {pmid32450399,
year = {2020},
author = {Tu, C and Chen, T and Zhou, Q and Liu, Y and Wei, J and Waniek, JJ and Luo, Y},
title = {Biofilm formation and its influences on the properties of microplastics as affected by exposure time and depth in the seawater.},
journal = {The Science of the total environment},
volume = {734},
number = {},
pages = {139237},
doi = {10.1016/j.scitotenv.2020.139237},
pmid = {32450399},
issn = {1879-1026},
mesh = {*Biofilms ; China ; Environmental Monitoring ; Microplastics ; Seawater ; Water Pollutants, Chemical ; },
abstract = {The effects of microbial colonization and biofilm formation on microplastics in the marine and coastal environments have aroused global concern recently. However, the simultaneous influences of exposure time and depth on biofilm formation, and subsequently on the properties variations of microplastics is less studied. In this study, polyethylene (PE) film was exposed at three depths (2 m, 6 m, and 12 m) for three time periods (30 days, 75 days, and 135 days) in the coastal seawater of Yellow Sea, China. The results show that the total amount of biofilms markedly increased with exposure time, but decreased with water depth. Typical morphologies and compositions of biofilms such as coccus-, rod-, disc-shaped bacteria and filaments, as well as a dense layer of extracellular polymeric substances were observed on the surfaces of the PE microplastics. Biofilm formation could decrease the hydrophobicity of PE microplastics, and increase the abundances of hydrophilic C-O and CO groups on the surface of PE. Alphaproteobacteria, Gammaproteobacteria and Bacteroidia were identified as the core microbiome of the PE associated biofilms, while the dominant bacteria families vary from the early to the late phases of the biofilm formation. Our results indicate that microplastics associated biofilms could affect the environmental processes and fates of microplastics in the marine and coastal environment.},
}
@article {pmid32449144,
year = {2020},
author = {Hujslová, M and Gryndlerová, H and Bystrianský, L and Hršelová, H and Gryndler, M},
title = {Biofilm and planktonic microbial communities in highly acidic soil (pH &lt; 3) in the Soos National Nature Reserve, Czech Republic.},
journal = {Extremophiles : life under extreme conditions},
volume = {24},
number = {4},
pages = {577-591},
doi = {10.1007/s00792-020-01177-x},
pmid = {32449144},
issn = {1433-4909},
support = {CZ.02.1.01/0.0/0.0/16_013/0001821//Ministry of Education, Youth and Sports of the Czech Republic/ ; 17-09946S//Grantová Agentura České Republiky/ ; },
abstract = {Biofilm formation is a typical life strategy used by microorganisms populating acidic water systems. The same strategy might be used by microbes in highly acidic soils that are, however, neglected in this regard. In the present study, the microbial community in such highly acidic soil in the Soos National Nature Reserve (Czech Republic) has been investigated using high-throughput DNA sequencing and the organisms associated with biofilm life mode and those preferring planktonic life were distinguished using the biofilm trap technique. Our data show the differences between biofilm and planktonic microbiota fraction, although the majority of the organisms were capable of using both life modes. The by far most abundant prokaryotic genus was Acidiphilium and fungi were identified among the most abundant eukaryotic elements in biofilm formations. On the other hand, small flagellates from diverse taxonomical groups predominated in plankton. The application of cellulose amendment as well as the depth of sampling significantly influenced the composition of the detected microbial community.},
}
@article {pmid32446309,
year = {2020},
author = {Lundström, T and Lingström, P and Wattle, O and Carlén, A and Birkhed, D},
title = {Equine saliva components during mastication, and in vivo pH changes in the oral biofilm of sound and carious tooth surfaces after sucrose exposure.},
journal = {Acta veterinaria Scandinavica},
volume = {62},
number = {1},
pages = {21},
pmid = {32446309},
issn = {1751-0147},
abstract = {BACKGROUND: The role of saliva composition and dietary sugar in development of infundibular caries in equine cheek teeth is not fully understood. This study analysed electrolyte and urea concentrations in saliva in relation to different forage and measured pH changes after sucrose application in vivo in sound and carious cheek teeth.<br><br>RESULTS: Forage type had no effect on the equine saliva electrolyte concentrations, which varied considerably both intra- and inter-individually. Chewing resulted in increased values for all electrolytes except bicarbonate. Compared with stimulated human saliva, horse saliva after mastication, contained higher amounts of potassium, calcium and bicarbonate, and less phosphate. The in vivo pH measurements showed a lower resting pH and a more pronounced pH drop after sucrose application in carious teeth compared to sound teeth.<br><br>CONCLUSIONS: No large differences were found between the composition of equine saliva and human saliva. A more pronounced acidogenicity was found for the carious than sound teeth. Thus, the caries process in equine cheek teeth seems to follow the same pattern as in human teeth, caused by acid production by oral microorganisms after sugar consumption.},
}
@article {pmid32444896,
year = {2020},
author = {Yang, Z and Wang, Z and Lei, M and Zhu, J and Yang, Y and Wu, S and Yu, B and Niu, H and Ying, H and Liu, D and Wang, Y},
title = {Effects of Spo0A on Clostridium acetobutylicum with an emphasis on biofilm formation.},
journal = {World journal of microbiology &amp; biotechnology},
volume = {36},
number = {6},
pages = {80},
doi = {10.1007/s11274-020-02859-6},
pmid = {32444896},
issn = {1573-0972},
support = {21706123//the National Nature Science Foundation of China/ ; 21636003//Key Programme/ ; SBK2017010373//Outstanding Youth Foundation of Jiangsu Province of China/ ; 2018YFA0902200//National Key Research and Development Program of China/ ; 2018YFB1501705//National Key Research and Development Program of China/ ; KYCX18_1111//Postgraduate Research &amp; Practice Innovation Program of Jiangsu Province/ ; IRT_14R28//the Program for Changjiang Scholars and Innovative Research Team in University/ ; },
abstract = {Clostridium acetobutylicum is a well-known strain for biofuel production. In previous work, it was found that this strain formed biofilm readily during fermentation processes. Biofilm formation could protect cells and enhance productivities under environmental stresses in our previous work. To explore the molecular mechanism of biofilm formation, Spo0A of C. acetobutylicum was selected to investigate its influences on biofilm formation and other physiological performances. When spo0A gene was disrupted, the spo0A mutant could hardly form biofilm. The aggregation and adhesion abilities of the spo0A mutant as well as its swarming motility were dramatically reduced compared to those of wild type strain. Sporulation was also negatively influenced by spo0A disruption, and solvent production was almost undetectable in the spo0A mutant fermentation. Furthermore, proteomic differences between wild type strain and the spo0A mutant were consistent with physiological performances. This is the first study confirming a genetic clue to C. acetobutylicum biofilm and will be valuable for biofilm optimization through genetic engineering in the future.},
}
@article {pmid32444475,
year = {2020},
author = {Song, Y and Sun, M and Feng, L and Liang, X and Song, X and Mu, G and Tuo, Y and Jiang, S and Qian, F},
title = {Lactobacillus plantarum-12 Exopolysaccharides Have Anti-Biofilm Activity Against Shigella flexneri.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.00694-20},
pmid = {32444475},
issn = {1098-5336},
abstract = {In the developing countries, Shigella flexneri is the most common enteric pathogen causing bacillary dysentery. And the biofilm formation of S. flexneri can cause the emergence of antibiotic-resistant strains and serious threat to food safety and human health. In this study, the effects of Lactobacillus plantarum-12 exopolysaccharides (L-EPS) and S. flexneri exopolysaccharides (S-EPS) on the S. flexneri CMCC51574 biofilm formation were investigated. The results showed that L-EPS could decrease the polysaccharides production in the extracellular polymeric matrix of S. flexneri, and inhibit the biofilm formation of S. flexneri L-EPS could decrease the minimum biofilm elimination concentration (MBEC) of the antibiotics against S. flexneri biofilm and inhibit S. flexneri adhesion and invasion to the HT-29 cell monolayers, which might be ascribed to the S. flexneri biofilm disturbance by L-EPS. While the S-EPS exhibited the exactly opposite effects compared to L-EPS. The monosaccharide composition analysis showed that L-EPS was composed of mannose, glucuronic acid, galactosamine, glucose, galactose and xylose, with the molar ratio of 32.26: 0.99: 1.79: 5.63: 0.05: 4.07, and the S-EPS was composed of mannose, glucuronic acid, galactosamine, glucose, galactose, with the molar ratio of 25.43: 2.28: 7.13: 5.35. The L-EPS was separated to the neutral polysaccharide L-EPS 1-1 and the acidic polysaccharide L-EPS 2-1 by the ion exchange chromatography and gel chromatography. The L-EPS 2-1 exerted higher anti-biofilm activity than the L-EPS 1-1. The anti-biofilm activity of L-EPS might be associated with its structure.Importance:S. flexneri is a wide-spread food-borne pathogen causing food contamination and responsible for food poisoning outbreaks through various foods in developing countries. The biofilm formation of S. flexneri was not only difficult to be eliminated, but also increased the drug-resistant of the strain. In the present study, it was demonstrated that the L-EPS secreted by the Lactobacillus plantrum-12 could inhibit the biofilm formation, adhesion and invasion to HT-29 cells of S. flexneri And the L-EPS could also decrease the minimum biofilm elimination concentration (MBEC) of the antibiotics against S. flexneri biofilm. Therefore, the L-EPS was a bioactive macromolecule with the potential ability against the infections of the S. flexneri.},
}
@article {pmid32443816,
year = {2020},
author = {Khan, F and Yu, H and Kim, YM},
title = {Bactericidal Activity of Usnic Acid-Chitosan Nanoparticles against Persister Cells of Biofilm-Forming Pathogenic Bacteria.},
journal = {Marine drugs},
volume = {18},
number = {5},
pages = {},
pmid = {32443816},
issn = {1660-3397},
support = {NRF-2019R1A2C1087156//National Research Foundation of Korea/ ; R2020052//National Institute of Fisheries Science/ ; },
abstract = {The present study aimed to prepare usnic acid (UA)-loaded chitosan (CS) nanoparticles (UA-CS NPs) and evaluate its antibacterial activity against biofilm-forming pathogenic bacteria. UA-CS NPs were prepared through simple ionic gelification of UA with CS, and further characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and field-emission transmission electron microscopy. The UA-CS NPs presented a loading capacity (LC) of 5.2%, encapsulation efficiency (EE) of 24%, and a spherical shape and rough surface. The maximum release of UA was higher in pH 1.2 buffer solution as compared to that in pH 6.8 and 7.4 buffer solution. The average size and zeta potential of the UA-CS NPs was 311.5 ± 49.9 nm in diameter and +27.3 ± 0.8 mV, respectively. The newly prepared UA-CS NPs exhibited antibacterial activity against persister cells obtained from the stationary phase in batch culture, mature biofilms, and antibiotic-induced gram-positive and gram-negative pathogenic bacteria. Exposure of sub-inhibitory concentrations of UA-CS NPs to the bacterial cells resulted in a change in morphology. The present study suggests an alternative method for the application of UA into nanoparticles. Furthermore, the anti-persister activity of UA-CS NPs may be another possible strategy for the treatment of infections caused by biofilm-forming pathogenic bacteria.},
}
@article {pmid32443196,
year = {2020},
author = {Sun, X and Chen, B and Xia, B and Li, Q and Zhu, L and Zhao, X and Gao, Y and Qu, K},
title = {Impact of mariculture-derived microplastics on bacterial biofilm formation and their potential threat to mariculture: A case in situ study on the Sungo Bay, China.},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {262},
number = {},
pages = {114336},
doi = {10.1016/j.envpol.2020.114336},
pmid = {32443196},
issn = {1873-6424},
abstract = {Microplastics (MPs) pollution in the marine environment has attracted considerable global attention. However, the colonization of microorganisms on mariculture-derived MPs and their effects on mariculture remain poorly understood. In this study, the MPs (fishing nets, foams and floats) and a natural substrate, within size ranges (1-4 mm), were then incubated for 21 days in Sungo Bay (China), and the composition and diversity of bacterial communities attached on all substrates were investigated. Results showed that bacterial communities on MPs mainly originated from their surrounding seawater and sediment, with an average contribution on total MPs adherent population of 47.91% and 37.33%, respectively. Principle coordinate analysis showed that community similarity between MPs and surrounding seawater decreased with exposure time. In addition, lower average bacterial community diversity and higher relative abundances of bacteria from the genera Vibrio, Pseudoalteromonas and Alteromonas on MPs than those in their surrounding seawater and sediments indicated that MPs might enrich potential pathogens and bacteria related with carbohydrate metabolism. They are responsible for the significant differences in KEGG Orthology pathways (infectious disease and carbohydrate metabolism) between MPs and seawater. The KO pathway (Infectious Diseases) associated with MPs was also significantly higher than those with feathers in the nearshore area. MPs might be vectors for enrichment of potentially pathogenic Vibrio, and enhance the ecological risk of MPs to mariculture industry.},
}
@article {pmid32442664,
year = {2020},
author = {Liu, W and Lu, H and Chu, X and Lou, T and Zhang, N and Zhang, B and Chu, W},
title = {Tea polyphenols inhibits biofilm formation, attenuates the quorum sensing-controlled virulence and enhances resistance to Klebsiella pneumoniae infection in Caenorhabditis elegans model.},
journal = {Microbial pathogenesis},
volume = {147},
number = {},
pages = {104266},
doi = {10.1016/j.micpath.2020.104266},
pmid = {32442664},
issn = {1096-1208},
abstract = {Bacteria cells can communicate with each other via quorum sensing (QS) system. Various physiological characteristics including virulence factors and biofilm formation are controlled by QS. So interrupting the bacterial communication is an alternative strategy instead of antibiotics for control bacterial infection. The aim of this study was to investigate the effects of tea polyphenols (TPs) on quorum sensing and virulence factors of Klebsiella pneumoniae. In vitro study showed that the anti-QS activity of tea polyphenols against Chromobacterium violaceum in violacein production. At sub-MICs, TPs inhibited the motility, reduced protease and exopolysaccharide (EPS) production and also biofilm formation in K. pneumoniae. In addition, in vivo study showed that tea polyphenols at 200 μg/mL and 400 μg/mL increased the survival rate of Caenorhabditis elegans to 73.3% and 82.2% against K. pneumonia infection. Our findings suggest that tea polyphenols can act as an effective QS inhibitor and can serve as a novel anti-virulence agent for the management of bacterial pathogens.},
}
@article {pmid32442576,
year = {2020},
author = {Swiontek Brzezinska, M and Walczak, M and Kalwasińska, A and Richert, A and Świątczak, J and Deja-Sikora, E and Burkowska-But, A},
title = {Biofilm formation during biodegradation of polylactide, poly (3,4 hydroxybutyrate) and poly(ε-caprolactone) in activated sludge.},
journal = {International journal of biological macromolecules},
volume = {159},
number = {},
pages = {539-546},
doi = {10.1016/j.ijbiomac.2020.05.107},
pmid = {32442576},
issn = {1879-0003},
abstract = {Biodegradable materials, namely pure polylactide (PLA), poly (3,4-hydroxybutyrate) (PHB), poly(ε-caprolactone) (PCL) were investigated to assess their degradability by activated sludge. The study aimed at the isolation of biofilm-forming bacteria and the determination of their hydrolytic activity toward the PLA, PHB, and PCL with embedded PHMG derivatives. The biological oxygen demand and physical properties (tensile strength, water vapor permeability, surface structure) of materials indicated that PCL was the best biodegradable film. Aeromonas and Rhodococcus isolated from the polymers' surface during the process of decomposition showed the ability to form biofilms. The introduction of PHMG derivatives into PLA, PCL, and PHB films did not affect biofilm formation and hydrolase activity for most of the isolates. PHMG derivatives at the concentration of 1% disturbed the degradation process.},
}
@article {pmid32441080,
year = {2020},
author = {Arutyunov, AS and Tsareva, TV and Kirakosyan, LG and Levchenko, IM},
title = {[Features and significance of adhesion of bacteria and fungi of the oral cavity as the initial stage of the formation of a microbial biofilm on dental polymer materials].},
journal = {Stomatologiia},
volume = {99},
number = {2},
pages = {79-84},
doi = {10.17116/stomat20209902179},
pmid = {32441080},
issn = {0039-1735},
mesh = {Bacteria ; Biofilms ; Candida albicans ; *Dental Materials ; Mouth ; *Polymers ; },
abstract = {OBJECTIVE: Characteristics of the adhesion of yeast fungi and oral bacteria of various types in vitro to samples of polymeric materials for fixed structures of dental prostheses, obtained using various technologies: adjective digital 3D printing and traditional methods.<br><br>MATERIAL AND METHODS: Conducted model experiments on the adhesion of bacterial (including the main periodontopic-pathogenic species - P. gingivalis, P. intermedia, etc.) and fungal pathogens (C. albicans) to standard samples of polymer materials NextDent C &amp; B Micro Filled Hybrid («NextDent», Netherlands), Detax Freeprint temp UV («Detax», Germany), obtained by digital additive 3D printing technology, and Luxatemp Automix Plus («DMG», Germany) and Acrytemp («Zhermack», Italy) - by the traditional method as a control. Removal of adhering microbes from the material was carried out using an ultrasound machine (exposure time 10 minutes, power 60 kHz).<br><br>RESULTS: The dependence of the degree of microbial adhesion on the nature of the material and processing technology (3D printing, milling) was established. The materials of NextDent C &amp; B Micro Filled Hybrid and Detax Freeprint temp UV showed high resistance to adhesion of clinical isolates of periodontal pathogenic bacteria and C. albicans fungi.<br><br>CONCLUSION: The lowest adhesion values for periodontopathogenic species and C. albicans fungi were detected when using samples of materials obtained by 3D printing: NextDent C &amp; B Micro Filled Hybrid and Detax Freeprint temp UV compared to Luxatemp Automix Plus and Acrytemp polymers.},
}
@article {pmid32440423,
year = {2020},
author = {Lee, M and Ponraja, G and McLeod, K and Chong, S},
title = {Breast Implant Illness: A Biofilm Hypothesis.},
journal = {Plastic and reconstructive surgery. Global open},
volume = {8},
number = {4},
pages = {e2755},
pmid = {32440423},
issn = {2169-7574},
abstract = {Background: &quot;Breast implant illness&quot; (BII) is a poorly defined cluster of nonspecific symptoms, attributed by patients as being caused by their breast implants. These symptoms can include joint pain, skin and hair changes, concentration, and fatigue. Many patients complaining of BII symptoms are dismissed as psychosomatic. There are currently over 10,000 peer-reviewed articles on breast implants, but at the time of commencing this study, only 2 articles discussed this entity. At the same time, mainstream media and social media are exploding with nonscientific discussion about BII.<br><br>Methods: We have prospectively followed 50 consecutive patients, self-referring for explantation due to BII. We analyzed their preoperative symptoms and followed up each patient with a Patient-Reported Outcome Questionnaire. All implants and capsules were, if possible, removed en bloc. Explanted implants were photographed. Implant shell and capsule sent for histology and microbiological culture.<br><br>Results: BII symptoms were not shown to correlate with any particular implant type, surface, or fill. There was no significant finding as to duration of implant or location of original surgery. Chronic infection was found in 36% of cases with Propionibacterium acnes the most common finding. Histologically, synoviocyte metaplasia was found in a significantly greater incidence than a matched cohort that had no BII symptoms (P = 0.0164). Eighty-four percent of patients reported partial or complete resolution of BII symptoms on Patient-Reported Outcome Questionnaire. None of the 50 patients would consider having breast implants again.<br><br>Conclusion: The authors believe BII to be a genuine entity worthy of further study. We have identified microbiological and histological abnormalities in a significant number of patients identifying as having BII. A large proportion of these patients have reported resolution or improvement of their symptoms in patient-reported outcomes. Improved microbiology culture techniques may identify a larger proportion of chronic infection, and further investigation of immune phenotypes and toxicology may also be warranted in this group.},
}
@article {pmid32439613,
year = {2020},
author = {Toledano-Osorio, M and Osorio, R and Aguilera, FS and Medina-Castillo, AL and Toledano, M and Osorio, E and Acosta, S and Chen, R and Aparicio, C},
title = {Polymeric nanoparticles protect the resin-dentin bonded interface from cariogenic biofilm degradation.},
journal = {Acta biomaterialia},
volume = {111},
number = {},
pages = {316-326},
doi = {10.1016/j.actbio.2020.05.002},
pmid = {32439613},
issn = {1878-7568},
abstract = {The objective was to assess doxycycline (Dox) and zinc (Zn) doped nanoparticles' (NPs) potential to protect the resin-dentin interface from cariogenic biofilm. Three groups of polymeric NPs were tested: unloaded, loaded with zinc and with doxycycline. NPs were applied after dentin etching. The disks were exposed to a cariogenic biofilm challenge in a Drip-Flow Reactor during 72 h and 7 d. Half of the specimens were not subjected to biofilm formation but stored 72 h and 7 d. LIVE/DEAD® viability assay, nano-dynamic mechanical assessment, Raman spectroscopy and field emission electron microscopy (FESEM) analysis were performed. The measured bacterial death rates, at 7 d were 46% for the control group, 51% for the undoped-NPs, 32% for Dox-NPs, and 87% for Zn-NPs; being total detected bacteria reduced five times in the Dox-NPs group. Zn-NPs treated samples reached, in general, the highest complex modulus values at the resin-dentin interface over time. Regarding the mineral content, Zn-NPs-treated dentin interfaces showed the highest mineralization degree associated to the phosphate peak and the relative mineral concentration. FESEM images after Zn-NPs application permitted to observe remineralization of the etched and non-resin infiltrated collagen layer, and bacteria were scarcely encountered. The combined antibacterial and remineralizing effects, when Zn-NPs were applied, reduced biofilm formation. Dox-NPs exerted an antibacterial role but did not remineralize the bonded interface. Undoped-NPs did not improve the properties of the interfaces. Application of Zn-doped NPs during the bonding procedure is encouraged. STATEMENT OF SIGNIFICANCE: Application of Zn-doped nanoparticles on acid etched dentin reduced biofilm formation and viability at the resin-dentin interface due to both remineralization and antibacterial properties. Doxycycline-doped nanoparticles also diminished oral biofilm viability, but did not remineralize the resin-dentin interface.},
}
@article {pmid32439578,
year = {2020},
author = {Rocca, DM and Silvero C, MJ and Aiassa, V and Cecilia Becerra, M},
title = {Rapid and effective phototreatment of biofilm infections using low doses of amoxicillin-coated gold nanoparticles.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {101811},
doi = {10.1016/j.pdpdt.2020.101811},
pmid = {32439578},
issn = {1873-1597},
abstract = {Bacterial biofilm are complex microbial communities covered by a matrix of extracellular polymeric substances, which develops when a community of microorganisms irreversibly adheres to a living or inert surface. This structure is considered an important virulence factor because it is difficult to eradicate and often responsible for treatment failures. This adherent community represents one of the greatest problems in public health due to the continued emergence of conventional antibiotic-therapy resistance. Photodynamic Antimicrobial Therapy (PACT) is a therapeutic alternative and promises to be an effective treatment against multiresistant bacteria biofilm, demonstrating a broad spectrum of action. This work demonstrates the reduction in biofilms of relevant clinical isolates (as Pseudomonas aeruginosa and Staphylococcus aureus) treated with PACT using low concentrations of amoxicillin-coated gold nanoparticles (amoxi@AuNP) as a photosensitizer. Moreover, the viability reduction of 60% in S. aureus biofilms and 70% in P. aeruginosa biofilms were obtained after three hours of irradiation with white light and amoxi@AuNP. Scanning electron microscopy analysis revealed that amoxi@AuNP could penetrate and cause damage to the biofilm matrix, and interact with bacteria cells. A strong biofilm production in P. aeruginosa was observed by confocal laser scanning microscopy using acridine orange as a probe, and a markedly decrease in live bacteria was appreciated when PACT was applied. The use of amoxi@AuNP for PACT allows the viability reduction of clinical Gram positive and Gram negative biofilms. This novel strategy needs shorter irradiation times and lower concentrations of nanoparticles than other reports described. This could be attributed to two major innovations: the selectivity for the bacterial wall given by the amoxicillin and the polydispersity of size and shapes with seems to contribute to the photo-antibacterial capacity.},
}
@article {pmid32439563,
year = {2020},
author = {Hans, S and Purkait, D and Nandan, S and Bansal, M and Hameed, S and Fatima, Z},
title = {Rec A disruption unveils cross talk between DNA repair and membrane damage, efflux pump activity, biofilm formation in Mycobacterium smegmatis.},
journal = {Microbial pathogenesis},
volume = {149},
number = {},
pages = {104262},
doi = {10.1016/j.micpath.2020.104262},
pmid = {32439563},
issn = {1096-1208},
abstract = {Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB) has emerged in recent decades as one of the leading causes of mortality worldwide. The burden of TB is alarmingly high, with one third affected global population as reported by WHO. Short-course treatment with an antibiotic is a powerful weapon to treat infection of susceptible MTB strain, however; MTB has developed resistance to anti-TB drugs, which is an escalating global health crisis. Thus there is urgent need to identify new drug targets. RecA is a 38 kilodalton protein required for the repair and maintenance of DNA and regulation of the SOS response. The objective of this study is to understand the effect of disruption of RecA gene (deletion mutant ΔdisA from previous study) in a surrogate model for MTB, Mycobacterium smegmatis. This study demonstrated that disruption of RecA causes enhanced susceptibility towards rifampicin and generation of ROS leading to lipid peroxidation and impaired membrane homeostasis as depicted by altered cell membrane permeability and efflux pump activity. Mass spectrometry based lipidomic analysis revealed decreased mycolic acid moieties, phosphatidylinositol mannosides (PIM), Phthiocerol dimycocerosate (DIM). Furthermore, biofilm formation was considerably reduced. Additionally, we have validated all the disrupted phenotypes by RT-PCR which showed a good correlation with the biochemical assays. Lastly, RecA mutant displayed reduced infectivity in Caenorhabditis elegans illustrating its vulnerability as antimycobacterial target. Together, present study establishes a link between DNA repair, drug efflux and biofilm formation and validates RecA as an effective drug target. Intricate studies are needed to further understand and exploit this therapeutic opportunity.},
}
@article {pmid32437832,
year = {2020},
author = {Tang, M and Wei, X and Wan, X and Ding, Z and Ding, Y and Liu, J},
title = {The role and relationship with efflux pump of biofilm formation in Klebsiella pneumoniae.},
journal = {Microbial pathogenesis},
volume = {147},
number = {},
pages = {104244},
doi = {10.1016/j.micpath.2020.104244},
pmid = {32437832},
issn = {1096-1208},
abstract = {This study aimed to identify the role and relationship with efflux pump of biofilm formation in Klebsiella pneumoniae. Sixty-one K. pneumoniae clinical isolates were collected between January and June of 2017 from the affiliated hospital of southwest medical university in Luzhou, China. The minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) were determined using broth microdilution method. Crystal violet (CV) staining and confocal laser scanning microscope (CLSM) were used to monitor biofilm formation. Efflux pump expression was investigated qualitatively and quantitatively by polymerase chain reaction (PCR) and reverse transcriptase quantitative PCR (RT-qPCR). Crystal violet staining was performed to evaluate the effect of efflux pump inhibitor carbonyl cyanide m-chlorophenyl hydrazine (CCCP) on K. pneumoniae biofilms. Our results showed that crystal violet staining and CLSM had good consistency in biofilm detection. Biofilm formation was an independent biological behavior of the strain and measured at 24 h was reasonable. Biofilms up-regulated antimicrobial resistance and expression of efflux pump gene acrA, emrB, oqxA, and qacEΔ1 in K. pneumoniae. CCCP inhibited biofilms but dose-dependent effect was obvious. Altogether, our data demonstrates that biofilm formation, as well as its interaction with efflux pump, promotes antimicrobial resistance in K. pneumoniae.},
}
@article {pmid32434379,
year = {2020},
author = {Yang, D and Reyes-De-Corcuera, JI},
title = {Continuous flow system for biofilm formation using controlled concentrations of Pseudomonas putida from chicken carcass and coupled to electrochemical impedance detection.},
journal = {Biofouling},
volume = {36},
number = {4},
pages = {389-402},
doi = {10.1080/08927014.2020.1763966},
pmid = {32434379},
issn = {1029-2454},
abstract = {Most studies dealing with monitoring the dynamics of biofilm formation use microbial suspensions at high concentrations. These conditions do not always represent food or water distribution systems. A continuous flow system capable of controlling the concentration of the microbial suspension stream from 104 to 106 CFU ml-1 is reported. Pseudomonas putida biofilms formed using 100-fold, 1,000-fold or 10,000-fold diluted bacterial suspensions were monitored in-line by electrochemical impedance spectroscopy (EIS) and total plate counts. Randles equivalent circuit model and a modified Randles model with biofilm elements were used to fit the EIS data. In Randles equivalent circuit, the charge transfer resistance decreased as the biofilm formed. The log colony counts of the biofilm correlated to the charge transfer resistance. In the biofilm model, the biofilm resistance and the double layer capacitance decreased as the biofilm formed. The log colony counts of the biofilm correlated to the biofilm resistance.},
}
@article {pmid32433466,
year = {2020},
author = {Dong, Y and Li, S and Zhao, D and Liu, J and Ma, S and Geng, J and Lu, C and Liu, Y},
title = {IolR, a negative regulator of the myo-inositol metabolic pathway, inhibits cell autoaggregation and biofilm formation by downregulating RpmA in Aeromonas hydrophila.},
journal = {NPJ biofilms and microbiomes},
volume = {6},
number = {1},
pages = {22},
pmid = {32433466},
issn = {2055-5008},
abstract = {Aeromonas hydrophila is the causative agent of motile Aeromonad septicemia in fish. Previous studies have shown that the myo-inositol metabolism is essential for the virulence of this bacterium. IolR is a transcription inhibitor that negatively regulates myo-inositol metabolic activity. While in the process of studying the inositol catabolism in A. hydrophila Chinese epidemic strain NJ-35, we incidentally found that ΔiolR mutant exhibited obvious autoaggregation and increased biofilm formation compared to the wild type. The role of surface proteins in A. hydrophila autoaggregation was confirmed by different degradation treatments. Furthermore, calcium promotes the formation of aggregates, which disappear in the presence of the calcium chelator EGTA. Transcriptome analysis, followed by targeted gene deletion, demonstrated that biofilm formation and autoaggregation caused by the inactivation of iolR was due to the increased transcription of a RTX-family adhesion gene, rmpA. Further, IolR was determined to directly regulate the transcription of rmpA. These results indicated that iolR is negatively involved in autoaggregation and biofilm formation in A. hydrophila, and this involvement was associated with its inhibition on the expression of rmpA.},
}
@article {pmid32432813,
year = {2020},
author = {Luze, H and Holzer, J and Nischwitz, SP and Kamolz, LP},
title = {The importance of in vivo biofilm models for clinical practice.},
journal = {Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society},
volume = {28},
number = {4},
pages = {578-579},
doi = {10.1111/wrr.12819},
pmid = {32432813},
issn = {1524-475X},
}
@article {pmid32432137,
year = {2020},
author = {Ma, Q and Wang, H and Chen, ZN and Wu, YQ and Yu, DZ and Wang, PJ and Shi, HB and Su, KM},
title = {Removal of biofilm is essential for long-term ventilation tube retention.},
journal = {World journal of clinical cases},
volume = {8},
number = {9},
pages = {1592-1599},
pmid = {32432137},
issn = {2307-8960},
abstract = {BACKGROUND: Although long-term retention of a ventilation tube is required in many ear diseases, spontaneous removal of conventional ventilation tube is observed in patients within 3 to 12 mo. To address this issue, we aimed to determine a new method for long-term retention of the ventilation tube.<br><br>AIM: To explore the value of removing the biofilm for long-term retention of tympanostomy ventilation tubes.<br><br>METHODS: A case-control study design was used to evaluate the safety and effectiveness of long-term tube retention by directly removing the biofilm (via surgical exfoliation) in patients who underwent myringotomy with ventilation tube placement. The patients were randomly divided into two groups: Control group and treatment group. Patients in the treatment group underwent regular biofilm exfoliation surgery in the clinic, whereas those in the control group did not have their biofilm removed. Only conventional ventilation tubes were placed in this study. Outcome measures were tube position and patency. Tube retention time and any complications were documented.<br><br>RESULTS: Eight patients with biofilm removal and eight patients without biofilm removal as a control group were enrolled in the study. The tympanostomy tube retention time was significantly longer in the treatment group (43.5 ± 26.4 mo) than in the control group (9.5 ± 6.9 mo) (P = 0.003). More tympanostomy tubes were found to be patent and in correct position in the treatment group during the follow-up intervals than in the control group (P = 0.01).<br><br>CONCLUSION: Despite the use of short-term ventilation tubes, direct biofilm removal can be a well-tolerated and effective treatment for long-term tube retention of tympanostomy ventilation tubes in patients who underwent myringotomy.},
}
@article {pmid32432073,
year = {2020},
author = {Soukarieh, F and Liu, R and Romero, M and Roberston, SN and Richardson, W and Lucanto, S and Oton, EV and Qudus, NR and Mashabi, A and Grossman, S and Ali, S and Sou, T and Kukavica-Ibrulj, I and Levesque, RC and Bergström, CAS and Halliday, N and Mistry, SN and Emsley, J and Heeb, S and Williams, P and Cámara, M and Stocks, MJ},
title = {Hit Identification of New Potent PqsR Antagonists as Inhibitors of Quorum Sensing in Planktonic and Biofilm Grown Pseudomonas aeruginosa.},
journal = {Frontiers in chemistry},
volume = {8},
number = {},
pages = {204},
pmid = {32432073},
issn = {2296-2646},
support = {/WT_/Wellcome Trust/United Kingdom ; },
abstract = {Current treatments for Pseudomonas aeruginosa infections are becoming less effective because of the increasing rates of multi-antibiotic resistance. Pharmacological targeting of virulence through inhibition of quorum sensing (QS) dependent virulence gene regulation has considerable therapeutic potential. In P. aeruginosa, the pqs QS system regulates the production of multiple virulence factors as well as biofilm maturation and is a promising approach for developing antimicrobial adjuvants for combatting drug resistance. In this work, we report the hit optimisation for a series of potent novel inhibitors of PqsR, a key regulator of the pqs system, bearing a 2-((5-methyl-5H-[1,2,4]triazino[5,6-b]indol-3-yl)thio) acetamide scaffold. The initial hit compound 7 (PAO1-L IC50 0.98 ± 0.02 μM, PA14 inactive at 10 μM) was obtained through a virtual screening campaign performed on the PqsR ligand binding domain using the University of Nottingham Managed Chemical Compound Collection. Hit optimisation gave compounds with enhanced potency against strains PAO1-L and PA14, evaluated using P. aeruginosa pqs-based QS bioreporter assays. Compound 40 (PAO1-L IC50 0.25 ± 0.12 μM, PA14 IC50 0.34 ± 0.03 μM) is one of the most potent PqsR antagonists reported showing significant inhibition of P. aeruginosa pyocyanin production and pqs system signaling in both planktonic cultures and biofilms. The co-crystal structure of 40 with the PqsR ligand binding domain revealed the specific binding interactions occurring between inhibitor and this key regulatory protein.},
}
@article {pmid32431810,
year = {2020},
author = {Pijls, BG and Sanders, IMJG and Kujiper, EJ and Nelissen, RGHH},
title = {Induction heating for eradicating Staphylococcus epidermidis from biofilm.},
journal = {Bone &amp; joint research},
volume = {9},
number = {4},
pages = {192-199},
pmid = {32431810},
issn = {2046-3758},
abstract = {Aims: Induction heating is a noninvasive, nonantibiotic treatment modality that can potentially be used to cause thermal damage to the bacterial biofilm on the metal implant surface. The purpose of this study was to determine the effectiveness of induction heating on killing Staphylococcus epidermidis from biofilm and to determine the possible synergistic effect of induction heating and antibiotics.<br><br>Methods: S. epidermidis biofilms were grown on titanium alloy (Ti6Al4V) coupons for 24 hours (young biofilm) and seven days (mature biofilm). These coupons with biofilm were heated to temperatures of 50°C, 55°C, 60°C, 65°C, 70°C, 80°C, and 90°C for 3.5 minutes and subsequently exposed to vancomycin and rifampicin at clinically relevant concentrations.<br><br>Results: For the young biofilm, total eradication was observed at 65°C or higher for 3.5 minutes followed by 24 hours of vancomycin 10 mg/l and rifampicin 1 mg/l. For the mature biofilm, total eradication was observed at 60°C for 3.5 minutes followed by 24 hours of vancomycin 10 mg/l and rifampicin 1 mg/l. Total eradication was also observed at 60°C for 3.5 minutes followed by 24 hours of vancomycin 1 mg/l and rifampicin 1 mg/l followed by another thermal shock of 60°C for 3.5 minutes (two thermal shocks).<br><br>Conclusion: Induction heating of Ti6Al4V coupons is effective in reducing bacterial load in vitro for S. epidermidis biofilms. Induction heating and antibiotics have a synergistic effect resulting in total eradication of the biofilm at 60°C or higher for clinically relevant concentrations of vancomycin and rifampicin.Cite this article:Bone Joint Res. 2020;9(4):192-199.},
}
@article {pmid32431213,
year = {2020},
author = {Said, MB and Saad, MB and Bousselmi, L and Ghrabi, A},
title = {Use of the catalytic complex TiO2/red cabbage anthocyanins to reduce the biofilm formation by planktonic bacteria.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-9},
doi = {10.1080/09593330.2020.1771432},
pmid = {32431213},
issn = {1479-487X},
abstract = {The bacterial cells dwelling within the biofilm usually develop resistance against common disinfectants. In this current study, to improve the effectiveness of photocatalytic treatment, a natural sensitizer in combination with unsupported titanium dioxide nanoparticles (TiO2-NPs) was used to optimize the absorbance of NPs in the visible region and, to enhance the catalytic activity of the semiconductor. Different kinetic parameters were determined according to the first-order and the biphasic models to evaluate the ability of tested bacteria to form biofilm under different photocatalytic treatment conditions. As a result, the addition of red cabbage anthocyanins (RCA) as photosensitizer allows the enhancement of biocide activity of TiO2-NPs and the reduction of biofilm formation by tested bacteria.},
}
@article {pmid32429830,
year = {2020},
author = {Souza, C and Mota, HF and Faria, YV and Cabral, FO and Oliveira, DR and Sant'Anna, LO and Nagao, PE and Santos, CDS and Moreira, LO and Mattos-Guaraldi, AL},
title = {Resistance to Antiseptics and Disinfectants of Planktonic and Biofilm-Associated Forms of Corynebacterium striatum.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2019.0124},
pmid = {32429830},
issn = {1931-8448},
abstract = {Disinfection and antisepsis are of primary importance in controlling nosocomial infections and outbreaks by pathogens expressing multiple resistance to antimicrobial agents (multidrug-resistant [MDR]) used in therapy. Nowadays, infections related to health services (HAIs) due to MDR and multidrug-susceptible (MDS) Corynebacterium striatum should not be underestimated, including patients using invasive medical devices. The virulence potential of C. striatum needs further investigation. Currently, susceptibility profiles of planktonic and/or sessile forms of four C. striatum strains of different pulsed-field gel electrophoresis types were examined as biocides based on the manufacturer's recommendations: 2% glutaraldehyde (GA), 2% peracetic acid (PA), 1% potassium monopersulfate (Virkon®; VK), 1% sodium hypochlorite (SH), and 70% ethyl alcohol (ET). Time-kill assays using 2% bovine serum albumin (BSA) were performed for evaluation of influence of organic matter on biocides effects. Planktonic forms expressed GA resistance at different levels. C. striatum viability was observed until 2, 4, 20, and 30 min for MDR 2369/II, MDS 1954/IV, MDR 1987/I, and MDS 1961/III strains, respectively. In contrast to GA, the biocides PA, VK24h, SH, and ET had higher effective bacterial mortality. However, storage of VK (48 hr) reduced their biocide activities. Moreover, mature biofilms were produced on abiotic substrates, including steel surfaces. Post-treatment with GA (30 min), survival of sessile forms was ≥100% than planktonic forms of all C. striatum tested strains. Independent of biocides tested, BSA increased the survival of planktonic and sessile forms (p ≤ 0.005). Present data indicated that hospital staff should be aware of dissemination and eradication of HAIs by C. striatum presenting resistance to biocides, including high-level disinfectants, such as GA.},
}
@article {pmid32429187,
year = {2020},
author = {Bumunang, EW and Ateba, CN and Stanford, K and Niu, YD and Wang, Y and McAllister, TA},
title = {Activity of Bacteriophage and Complex Tannins against Biofilm-Forming Shiga Toxin-Producing Escherichia coli from Canada and South Africa.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {9},
number = {5},
pages = {},
pmid = {32429187},
issn = {2079-6382},
support = {FOS.07.17//Beef Cattle Research Council/ ; 98983//National Research Foundation of South Africa/ ; 001//Alberta Agriculture and Forestry, Growing Forward 2/ ; },
abstract = {Bacteriophages, natural killers of bacteria, and plant secondary metabolites, such as condensed tannins, are potential agents for the control of foodborne pathogens. The first objective of this study evaluated the efficacy of a bacteriophage SA21RB in reducing pre-formed biofilms on stainless-steel produced by two Shiga toxin-producing Escherichia coli (STEC) strains, one from South Africa and the other from Canada. The second objective examined the anti-bacterial and anti-biofilm activity of condensed tannin (CT) from purple prairie clover and phlorotannins (PT) from brown seaweed against these strains. For 24-h-old biofilms, (O113:H21; 6.2 log10 colony-forming units per square centimeter (CFU/cm2) and O154:H10; 5.4 log10 CFU/cm2), 3 h of exposure to phage (1013 plaque-forming units per milliliter (PFU/mL)) reduced (p ≤ 0.05) the number of viable cells attached to stainless-steel coupons by 2.5 and 2.1 log10 CFU/cm2 for O113:H21 and O154:H10, respectively. However, as biofilms matured, the ability of phage to control biofilm formation declined. In biofilms formed for 72 h (O113:H21; 5.4 log10 CFU/cm2 and O154:H10; 7 log10 CFU/cm2), reductions after the same duration of phage treatment were only 0.9 and 1.3 log10 CFU/cm2 for O113:H21 and O154:H10, respectively. Initial screening of CT and PT for anti-bacterial activity by a microplate assay indicated that both STEC strains were less sensitive (p ≤ 0.05) to CT than PT over a concentration range of 25-400 µg/mL. Based on the lower activity of CT (25-400 µg/mL), they were not further examined. Accordingly, PT (50 µg/mL) inhibited (p ≤ 0.05) biofilm formation for up to 24 h of incubation at 22 °C, but this inhibition progressively declined over 72 h for both O154:H10 and O113:H21. Scanning electron microscopy revealed that both SA21RB and PT eliminated 24 h biofilms, but that both strains were able to adhere and form biofilms on stainless-steel coupons at longer incubation times. These findings revealed that phage SA21RB is more effective at disrupting 24 than 72 h biofilms and that PT were able to inhibit biofilm formation of both E. coli O154:H10 and O113:H21 for up to 24 h.},
}
@article {pmid32429151,
year = {2020},
author = {Ingendoh-Tsakmakidis, A and Eberhard, J and Falk, CS and Stiesch, M and Winkel, A},
title = {In Vitro Effects of Streptococcus oralis Biofilm on Peri-Implant Soft Tissue Cells.},
journal = {Cells},
volume = {9},
number = {5},
pages = {},
pmid = {32429151},
issn = {2073-4409},
support = {WVZN2860//Niedersächsische Ministerium für Wissenschaft und Kultur/ ; WVZN2860.//Volkswagen Foundation/ ; },
abstract = {Human gingival epithelial cells (HGEps) and fibroblasts (HGFs) are the main cell types in peri-implant soft tissue. HGEps are constantly exposed to bacteria, but HGFs are protected by connective tissue as long as the mucosa-implant seal is intact. Streptococcus oralis is one of the commensal bacteria, is highly abundant at healthy implant sites, and might modulate soft tissue cells-as has been described for other streptococci. We have therefore investigated the effects of the S. oralis biofilm on HGEps and HGFs. HGEps or HGFs were grown separately on titanium disks and responded to challenge with S. oralis biofilm. HGFs were severely damaged after 4 h, exhibiting transcriptional inflammatory and stress responses. In contrast, challenge with S. oralis only induced a mild transcriptional inflammatory response in HGEps, without cellular damage. HGFs were more susceptible to the S. oralis biofilm than HGEps. The pro-inflammatory interleukin 6 (IL-6) was attenuated in HGFs, as was interleukin 8 (CXCL8) in HGEps. This indicates that S. oralis can actively protect tissue. In conclusion, commensal biofilms can promote homeostatic tissue protection, but only if the implant-mucosa interface is intact and HGFs are not directly exposed.},
}
@article {pmid32428444,
year = {2020},
author = {Riquelme, SA and Liimatta, K and Wong Fok Lung, T and Fields, B and Ahn, D and Chen, D and Lozano, C and Sáenz, Y and Uhlemann, AC and Kahl, BC and Britto, CJ and DiMango, E and Prince, A},
title = {Pseudomonas aeruginosa Utilizes Host-Derived Itaconate to Redirect Its Metabolism to Promote Biofilm Formation.},
journal = {Cell metabolism},
volume = {31},
number = {6},
pages = {1091-1106.e6},
doi = {10.1016/j.cmet.2020.04.017},
pmid = {32428444},
issn = {1932-7420},
support = {R35 HL135800/HL/NHLBI NIH HHS/United States ; S10 RR027050/RR/NCRR NIH HHS/United States ; UL1 TR001873/TR/NCATS NIH HHS/United States ; },
abstract = {The bacterium Pseudomonas aeruginosa is especially pathogenic, often being associated with intractable pneumonia and high mortality. How P. aeruginosa avoids immune clearance and persists in the inflamed human airway remains poorly understood. In this study, we show that P. aeruginosa can exploit the host immune response to maintain infection. Notably, unlike other opportunistic bacteria, we found that P. aeruginosa alters its metabolic and immunostimulatory properties in response to itaconate, an abundant host-derived immunometabolite in the infected lung. Itaconate induces bacterial membrane stress, resulting in downregulation of lipopolysaccharides (LPS) and upregulation of extracellular polysaccharides (EPS). These itaconate-adapted P. aeruginosa accumulate lptD mutations, which favor itaconate assimilation and biofilm formation. EPS, in turn, induces itaconate production by myeloid cells, both in the airway and systemically, skewing the host immune response to one permissive of chronic infection. Thus, the metabolic versatility of P. aeruginosa needs to be taken into account when designing therapies.},
}
@article {pmid32427342,
year = {2020},
author = {Chatterjee, S and Samal, B and Singh, P and Pradhan, BB and Verma, RK},
title = {Transition of a solitary to a biofilm community life style in bacteria: a survival strategy with division of labour.},
journal = {The International journal of developmental biology},
volume = {},
number = {},
pages = {},
doi = {10.1387/ijdb.190176sc},
pmid = {32427342},
issn = {1696-3547},
abstract = {Multicellularity is associated with higher eukaryotes having an organized division of labour and a coordinated action of different organs composed of multiple cell types. This division of different cell types and organizations to form a multicellular structure by developmental programming is a key to the multitasking of complex traits that enable higher eukaryotes to cope with fluctuating environmental conditions. Microbes such as bacteria, on the other hand, are unicellular and have flourished in diverse environmental conditions for a much longer time than eukaryotes in evolutionary history. In this review, we will focus on different strategies and functions exhibited by microbes that enable them to adapt to changes in lifestyle associated with transitioning from a unicellular solitary state to a complex community architecture known as a biofilm. We will also discuss various environmental stimuli and signaling processes which bacteria utilize to coordinate their social traits and enable themselves to form complex multicellular-like biofilm structures, and the division of labour operative within such communities driving their diverse social traits. We will also discuss here recent studies from our laboratory using a plant-associated bacterial pathogen as a model organism to elucidate the mechanism of bacterial cell-cell communication and the transition of a bacterial community to a multicellular-like structure driven by the complex regulation of traits influenced by cell density, as well as environmental sensing such as chemotaxis and nutrient availability. These studies are shedding important insights into bacterial developmental transitions and will help us to understand community cooperation and conflict using bacterial cell-cell communication as a model system.},
}
@article {pmid32425915,
year = {2020},
author = {Böttcher, B and Hoffmann, B and Garbe, E and Weise, T and Cseresnyés, Z and Brandt, P and Dietrich, S and Driesch, D and Figge, MT and Vylkova, S},
title = {The Transcription Factor Stp2 Is Important for Candida albicans Biofilm Establishment and Sustainability.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {794},
pmid = {32425915},
issn = {1664-302X},
abstract = {The fungal pathogen Candida albicans forms polymorphic biofilms where hyphal morphogenesis and metabolic adaptation are tightly coordinated by a complex intertwined network of transcription factors. The sensing and metabolism of amino acids play important roles during various phases of biofilm development - from adhesion to maturation. Stp2 is a transcription factor that activates the expression of amino acid permease genes and is required for environmental alkalinization and hyphal growth in vitro and during macrophage phagocytosis. While it is well established that Stp2 is activated in response to external amino acids, its role in biofilm formation remains unknown. In addition to widely used techniques, we applied newly developed approaches for automated image analysis to quantify Stp2-regulated filamentation and biofilm growth. Our results show that in the stp2Δ deletion mutant adherence to abiotic surfaces and initial germ tube formation were strongly impaired, but formed mature biofilms with cell density and morphological structures comparable to the control strains. Stp2-dependent nutrient adaptation appeared to play an important role in biofilm development: stp2Δ biofilms formed under continuous nutrient flow displayed an overall reduction in biofilm formation, whereas under steady conditions the mutant strain formed biofilms with lower metabolic activity, resulting in increased cell survival and biofilm longevity. A deletion of STP2 led to increased rapamycin susceptibility and transcriptional activation of GCN4, the transcriptional regulator of the general amino acid control pathway, demonstrating a connection of Stp2 to other nutrient-responsive pathways. In summary, the transcription factor Stp2 is important for C. albicans biofilm formation, where it contributes to adherence and induction of morphogenesis, and mediates nutrient adaption and cell longevity in mature biofilms.},
}
@article {pmid32425911,
year = {2020},
author = {Zhang, G and Lu, M and Liu, R and Tian, Y and Vu, VH and Li, Y and Liu, B and Kushmaro, A and Li, Y and Sun, Q},
title = {Inhibition of Streptococcus mutans Biofilm Formation and Virulence by Lactobacillus plantarum K41 Isolated From Traditional Sichuan Pickles.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {774},
pmid = {32425911},
issn = {1664-302X},
abstract = {Among cariogenic microbes, Streptococcus mutans is considered a major etiological pathogen of dental caries. Lactobacilli strains have been promoted as possible probiotic agents against S. mutans, although the inhibitory effect of Lactobacilli on caries has not yet been properly addressed. The objective of this study was to screen Lactobacillus strains found in traditional Sichuan pickles and to evaluate their antagonistic properties against S. mutans in vitro and in vivo. In the current study, we analyzed 54 Lactobacillus strains isolated from pickles and found that strain L. plantarum K41 showed the highest inhibitory effect on S. mutans growth as well as on the formation of exopolysaccharides (EPS) and biofilm in vitro. Scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM) revealed the reduction of both EPS and of the network-like structure in S. mutans biofilm when these bacteria were co-cultured with strain L. plantarum K41. Furthermore, when rats were treated with strain L. plantarum K41, there was a significant reduction in the incidence and severity of dental caries. Due to K41's origin in a high salinity environment, it showed a high tolerance to acids and salts. This may give this strain an advantage in harsh oral conditions. Results showed that L. plantarum K41 isolated from traditional Sichuan pickles effectively inhibited S. mutans biofilm formation and thus possesses a potential inhibitory effect on dental caries in vivo.},
}
@article {pmid32425737,
year = {2020},
author = {Xu, X and Peng, Q and Zhang, Y and Tian, D and Zhang, P and Huang, Y and Ma, L and Qiao, Y and Shi, B},
title = {A novel exopolysaccharide produced by Lactobacillus coryniformis NA-3 exhibits antioxidant and biofilm-inhibiting properties in vitro.},
journal = {Food &amp; nutrition research},
volume = {64},
number = {},
pages = {},
pmid = {32425737},
issn = {1654-661X},
abstract = {Background: Exopolysaccharides (EPSs) secreted from lactic acid bacteria are carbohydrate polymers with reported biological activities. In this study, we extracted and characterized the composition as well as antioxidant and biofilm-inhibitory properties of EPS from Lactobacillus coryniformis NA-3 isolated from northeast Chinese sauerkraut (Suan Cai).<br><br>Methods: Lactobacillus coryniformis NA-3 was identified with 16S rDNA amplification and Neighbor Joining (NJ) phylogenetic analysis. EPS derived from Lactobacillus coryniformis NA-3 (EPS-NA3) was analyzed, including compositions by high-performance liquid chromatography (HPLC), functional groups by Fourier-transform infrared spectroscopy (FT-IR) and glycosidic bond configuration by Hydrogen-1 Nuclear Magnetic Resonance (1H NMR). Antioxidant activity of EPS was evaluated with hydroxyl and superoxide radical-scavenging. Anti-biofilm activities of EPS-NA3 were checked through inhibition and dispersion.<br><br>Results: The monosaccharide composition of EPS included α-rhamnose, α-mannose, α-galactose, and α-glucose in a ratio of 2.6:1.0:5.0:3.3. The free radical-scavenging abilities of EPS-NA3 were 37.77% ± 1.56% and 78.87% ± 3.07% on hydroxyl and superoxide reactive oxygen species respectively. Moreover, EPS-NA3 attenuated the formation of Bacillus cereus and Salmonella typhimurium biofilms by inhibition ratios of approximately 80% and 40% respectively. Additionally, treatment with EPS-NA3 dispersed established biofilms of B. cereus and S. typhimurium by approximately 90% and 20% respectively.<br><br>Conclusion: These results suggest that EPS-NA3 may be developed as antioxidant and anti-biofilm agents for industrial and clinical applications due to its capacity of scavenging free radicals, inhibition of bacterial biofilm formation, and dispersion of established biofilms.},
}
@article {pmid32424471,
year = {2020},
author = {Julák, J and Vaňková, E and Válková, M and Kašparová, P and Masák, J and Scholtz, V},
title = {Combination of non-thermal plasma and subsequent antibiotic treatment for biofilm re-development prevention.},
journal = {Folia microbiologica},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12223-020-00796-3},
pmid = {32424471},
issn = {1874-9356},
support = {Progress Q25//Charles University/ ; 17-15936S//GA CR/ ; },
abstract = {The influence of non-thermal plasma (NTP) treatment on the prevention of antibiotic resistance of microbial biofilms was studied. Staphylococcus epidermidis and Escherichia coli bacteria and a yeast Candida albicans, grown on the surface of Ti-6Al-4V alloy used in the manufacture of prosthetic implants, were employed. Their biofilms were exposed to NTP produced by DC cometary discharge and subsequently treated with antibiotics commonly used for the treatment of infections caused by them: erythromycin (ERY), polymyxin B (PMB), or amphotericin B (AMB), respectively. All biofilms displayed significant reduction of their metabolic activity after NTP exposure, the most sensitive was S. epidermidis. The subsequent action of antibiotics caused significant decrease in the metabolic activity of S. epidermidis and E. coli, but not C. albicans, although the area covered by biofilm decreased in all cases. The combined effect of NTP with antibiotics was thus proved to be a promising strategy in bacterial pathogen treatment.},
}
@article {pmid32422308,
year = {2020},
author = {Falkinham, JO},
title = {Disinfection and cleaning of heater-cooler units: suspension- and biofilm-killing.},
journal = {The Journal of hospital infection},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jhin.2020.05.005},
pmid = {32422308},
issn = {1532-2939},
abstract = {BACKGROUND: Non-tuberculous mycobacteria (NTM) infections in cardiac surgery patients, caused by Mycobacterium chimaera or Mycobacterium abscessus, have been traced to NTM-aerosols produced by heater-cooler units of cardiopulmonary bypass equipment.<br><br>AIM: To develop a protocol to disinfect the water reservoir(s) of heater-coolers to reduce NTM numbers and thereby prevent potential NTM aerosolization; and to devise an approach to disrupt surface biofilms of heater-coolers to reduce reinoculation of the heater-cooler reservoir(s) after disinfection.<br><br>METHODS: A laboratory-scale Centers for Disease Control and Prevention bioreactor and a heater-cooler were inoculated with M. chimaera or M. abscessus to measure the ability of different disinfection protocols to reduce NTM colony-forming units in water and biofilm samples and to delay the reappearance of NTM after disinfection.<br><br>FINDINGS: The combination of an enzyme detergent cleaning agent and Clorox® were equivalent to Clorox alone in reducing M. chimaera cfu in heater-cooler water reservoir samples. However, reappearance of those bacteria was delayed by 12 weeks by the combination of enzyme detergent cleaning agent and Clorox exposure compared to Clorox disinfection alone.<br><br>CONCLUSION: A combination of an enzyme detergent and Clorox was an effective disinfection treatment and significantly delayed the reappearance of M. chimaera in the heater-cooler reservoir.},
}
@article {pmid32420501,
year = {2020},
author = {Venkata, S and Zeeshan, F and Kamal, A and Luqman, AK and Saif, H},
title = {Efficiency of vanillin in impeding metabolic adaptability and virulence of Candida albicans by inhibiting glyoxylate cycle, morphogenesis, and biofilm formation.},
journal = {Current medical mycology},
volume = {6},
number = {1},
pages = {1-8},
pmid = {32420501},
issn = {2423-3439},
abstract = {Background and Purpose: Candida albicans is the fourth most common cause of nosocomial fungal infections across the world. The current drug regimens are suffering from such drawbacks as drug resistance, toxicity, and costliness; accordingly, they highlight the need for the discovery of novel drug agents. The metabolic adaptability under low-carbon conditions and expression of functional virulence traits mark the success of pathogens to cause infection. The metabolic pathways, such as glyoxylate cycle (GC), enable C. albicans to survive under glucose-deficient conditions prevalent in the hostile niche. Therefore, the key enzymes, namely isocitrate lyase (ICL) and malate synthase (MLS), represent attractive agents against C. albicans. Similarly, virulence traits, such as morphogenesis and biofilm formation, are the crucial determinants of C. albicans pathogenicity. Regarding this, the present study was conducted to uncover the role of vanillin (Van), a natural food flavoring agent, in inhibiting GC, yeast-to-hyphal transition, and biofilm formation in human fungal pathogen C. albicans.<br><br>Materials and Methods: For the determination of hypersensitivity under low-glucose conditions, phenotypic susceptibility assay was utilized. In addition, enzyme activities were estimated based on crude extracts while in-silico binding was confirmed by molecular docking. The assessment of morphogenesis was accomplished using hyphal-inducing media, and biofilm formation was estimated using calcofluor staining, MTT assay, and biomass measurement. Additionally, the in vivo efficacy of Van was demonstrated using Caenorhabditis elegans nematode model.<br><br>Results: Based on the results, Van was found to be a potent GC inhibitor that phenocopied ICL1 deletion mutant and displayed hypersensitivity under low-carbon conditions. Accordingly, Van facilitated the inhibition of ICL and MLS activities in vitro. Molecular docking analyses revealed the in-silico binding affinity of Van with Icl1p and Mls1p. Those analyses were also confirmative of the binding of Van to the active sites of both proteins with better binding energy in comparison to their known inhibitors. Furthermore, Van led to the attenuation of such virulence traits as morphogenesis, biofilm formation, and cell adherence. Finally, the antifungal efficacy of Van was demonstrated by the enhanced survival of C. elegans with Candida infection. The results also confirmed negligible hemolytic activity on erythrocytes.<br><br>Conclusion: As the findings of the present study indicated, Van is a persuasive natural compound that warrants further attention to exploit its anticandidal potential.},
}
@article {pmid32419108,
year = {2020},
author = {Romiyo, V and Wilson, JW},
title = {Phenotypes, transcriptome, and novel biofilm formation associated with the ydcI gene.},
journal = {Antonie van Leeuwenhoek},
volume = {113},
number = {8},
pages = {1109-1122},
doi = {10.1007/s10482-020-01412-7},
pmid = {32419108},
issn = {1572-9699},
support = {Dennis M. Cook Endowed Gregor Mendel Chair in Genetics//Villanova University/ ; },
abstract = {The ydcI gene has previously been shown to encode a DNA-binding protein involved with acid stress resistance and induced biofilm formation in a strain of Salmonella enterica serovar Typhimurium. In addition, characterisation of the ydcI gene in Escherichia coli and other bacteria demonstrated strikingly different tolerance for induced ydcI expression across Gram negative species. In this report, we investigated the conservation of these phenotypes across multiple strains of S. Typhimurium and E. coli, and we used RNA Seq to identify the transcriptome of the ΔydcI mutant compared to WT in S. Typhimurium and E. coli (to establish the YdcI regulon in each species). We constructed deletion mutants in each species based on the RNA Seq results and tested these mutants for the relevant ydcI-related phenotypes. Though no evidence for a role in these phenotypes was found via the RNA Seq deletion mutants, we found that the ydcI-induced biofilm in S. Typhimurium is formed independently of the major biofilm genes csgA and bcsA indicating a potentially novel type of biofilm formation.},
}
@article {pmid32418905,
year = {2020},
author = {Khan, F and Lee, JW and Javaid, A and Park, SK and Kim, YM},
title = {Inhibition of biofilm and virulence properties of Pseudomonas aeruginosa by sub-inhibitory concentrations of aminoglycosides.},
journal = {Microbial pathogenesis},
volume = {146},
number = {},
pages = {104249},
doi = {10.1016/j.micpath.2020.104249},
pmid = {32418905},
issn = {1096-1208},
abstract = {Aminoglycosides are a commonly used class of antibiotics; however, their application has been discontinued due to the emergence of multi-drug resistance bacterial strains. In the present study, the subinhibitory concentrations (sub-MIC) of several aminoglycosides were determined and tested as an antibiofilm and for their anti-virulence properties against Pseudomonas aeruginosa PAO1, which is an opportunistic foodborne pathogen. P. aeruginosa PAO1 exhibits multiple mechanisms of resistance, including the formation of biofilm and production of several virulence factors, against aminoglycoside antibiotics. The sub-MIC of these antibiotics exhibited biofilm inhibition of P. aeruginosa in alkaline TSB (pH 7.9). Moreover, various concentrations of these aminoglycosides also eradicate the mature biofilm of P. aeruginosa. In the presence of sub-MIC of aminoglycosides, the morphological changes of P. aeruginosa were found to change from rod-shaped to the filamentous, elongated, and streptococcal forms. Similar growth conditions and sub-MIC of aminoglycosides were also found to attenuate several virulence properties of P. aeruginosa PAO1. Molecular docking studies demonstrate that these aminoglycosides possess strong binding properties with the LasR protein, which is a well-characterized quorum-sensing receptor of P. aeruginosa. The present study suggests a new approach to revitalize aminoglycosides as antibiofilm and antivirulence drugs to treat infections caused by pathogenic bacteria.},
}
@article {pmid32418125,
year = {2020},
author = {van Geelen, L and Kaschani, F and Sazzadeh, SS and Adeniyi, ET and Meier, D and Proksch, P and Pfeffer, K and Kaiser, M and Ioerger, TR and Kalscheuer, R},
title = {Natural brominated phenoxyphenols kill persistent and biofilm-incorporated cells of MRSA and other pathogenic bacteria.},
journal = {Applied microbiology and biotechnology},
volume = {104},
number = {13},
pages = {5985-5998},
doi = {10.1007/s00253-020-10654-4},
pmid = {32418125},
issn = {1432-0614},
support = {270650915 / GRK2158//Deutsche Forschungsgemeinschaft/ ; KA 2259/5-1//Deutsche Forschungsgemeinschaft/ ; KA 2894/7-1//Deutsche Forschungsgemeinschaft/ ; N/A//Jürgen Manchot Stiftung/ ; },
abstract = {Due to a high unresponsiveness to chemotherapy, biofilm formation is an important medical problem that frequently occurs during infection with many bacterial pathogens. In this study, the marine sponge-derived natural compounds 4,6-dibromo-2-(2',4'-dibromophenoxy)phenol and 3,4,6-tribromo-2-(2',4'-dibromophenoxy)phenol were found to exhibit broad antibacterial activity against medically relevant gram-positive and gram-negative pathogens. The compounds were not only bactericidal against both replicating and stationary phase-persistent planktonic cells of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa; they also killed biofilm-incorporated cells of both species while not affecting biofilm structural integrity. Moreover, these compounds were active against carbapenemase-producing Enterobacter sp. This simultaneous activity of compounds against different growth forms of both gram-positive and gram-negative bacteria is rare. Genome sequencing of spontaneous resistant mutants and proteome analysis suggest that resistance is mediated by downregulation of the bacterial EIIBC phosphotransferase components scrA and mtlA in MRSA likely leading to a lower uptake of the molecules. Due to their only moderate cytotoxicity against human cell lines, phenoxyphenols provide an interesting new scaffold for development of antimicrobial agents with activity against planktonic cells, persisters and biofilm-incoporated cells of ESKAPE pathogens. KEY POINTS: • Brominated phenoxyphenols kill actively replicating and biofilm-incorporated bacteria. • Phosphotransferase systems mediate uptake of brominated phenoxyphenols. • Downregulation of phosphotransferase systems mediate resistance.},
}
@article {pmid32417953,
year = {2020},
author = {Wang, J and Lu, J and Zhang, Y and Wu, J and Luo, Y},
title = {Unique Bacterial Community of the Biofilm on Microplastics in Coastal Water.},
journal = {Bulletin of environmental contamination and toxicology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00128-020-02875-0},
pmid = {32417953},
issn = {1432-0800},
support = {41671319//National Natural Science Foundation of China/ ; tsqn201812116//Taishan Scholars Program of Shandong Province/ ; Y739011021//Two-Hundred Talents Plan of Yantai/ ; QYZDJ-SSW-DQC015//Key Research Program of Frontier Sciences of CAS/ ; Y629041021//One Hundred Talents Program of Chinese Academy of Sciences/ ; },
abstract = {Being immersed in seawater for a few days, microorganisms will adhere to the surface of different materials and form biofilms. After being immersed in seawater for 1 week, high-throughput sequencing method was used to analyze the bacterial community structure of the biofilms on the surface of microbeads with different materials including steel, SiO2, and polyvinyl chloride (PVC). Operational taxonomic unit clustering results showed that some differences existed in the bacterial communities attached to the surface of different microbeads. Each microbead made by different material had its unique bacterial community. The heatmap indicated that the dominant genera on the surface of different microbeads were different from each other. Quantitative analysis showed that the relative abundance of dominant genera were different among different types of microbeads. Beta diversity analysis and principal component analysis showed that difference in the bacterial community on surface of steel-bead and PVC-bead was the most significant.},
}
@article {pmid32417519,
year = {2020},
author = {Luan, X and Zhang, H and Tian, Z and Yang, M and Wen, X and Zhang, Y},
title = {Microbial community functional structure in an aerobic biofilm reactor: Impact of streptomycin and recovery.},
journal = {Chemosphere},
volume = {255},
number = {},
pages = {127032},
doi = {10.1016/j.chemosphere.2020.127032},
pmid = {32417519},
issn = {1879-1298},
abstract = {Antibiotics can affect microbial community structure and promote antibiotic resistance. However, the course of microbial community recovery in wastewater treatment systems after antibiotic disturbance remains unclear. Herein, multiple molecular biology tools, including 16S amplicon sequencing, GeoChip 5.0, quantitative polymerase chain reaction (qPCR), and metagenomic sequencing, were used to investigate the year-long (352 d) recovery of the microbial community functional structure in an aerobic biofilm reactor. Nitrification was completely inhibited under 50 mg/L of streptomycin spiking (STM_50) due to the significant reduction of ammonia-oxidizing bacteria, but recovered to original pre-disturbance levels after streptomycin removal, indicating the high resilience of ammonia-oxidizing bacteria. Bacterial community richness and diversity decreased significantly under STM_50 (p < 0.05), but recovered to levels similar to those observed before disturbance after 352 d. In contrast, bacterial composition did not recover to the original structure. The carbon degradation and nitrogen cycling functional community significantly changed after recovery compared to that observed pre-disturbance (p < 0.05), thus indicating functional redundancy. Additionally, levels of aminoglycoside and total antibiotic resistance genes under STM_50 (relative abundance, 0.33 and 0.80, respectively) and after one year of recovery (0.12 and 0.29, respectively) were higher than the levels detected pre-disturbance (0.04 and 0.24, respectively). This study provides an overall depiction of the recovery of the microbial community functional structure after antibiotic exposure. Our findings give notice that recovery caused by antibiotic disturbance in the water environment should be taken more seriously, and that engineering control strategies should be implemented to prevent the antibiotic pollution of wastewater.},
}
@article {pmid32417483,
year = {2020},
author = {Xu, Y and Ou, Q and Zhou, X and He, Q and Wu, Z and Huang, R and Song, J and Ma, J and Huangfu, X},
title = {Impacts of carrier properties, environmental conditions and extracellular polymeric substances on biofilm formation of sieved fine particles from activated sludge.},
journal = {The Science of the total environment},
volume = {731},
number = {},
pages = {139196},
doi = {10.1016/j.scitotenv.2020.139196},
pmid = {32417483},
issn = {1879-1026},
abstract = {To investigate the effect of properties of carriers, environmental conditions and extracellular polymeric substances (EPS) on the initial adhesion of biofilm formation in biofilm-based reactors, a quartz crystal microbalance with dissipation (QCM-D) was applied to monitor the deposition rates and viscoelastic properties of sieved sludge particles on model biocarriers. The results suggested that surface charge, hydrophobicity and surface coating of five representative carriers influenced deposition rates and viscoelastic properties of biofilm, whose variation with NaCl concentrations was controlled by not only the Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction but also non-DLVO forces. On hydrophobic surface, the addition of cationic substances enhanced the deposition rates and the compaction of deposited layer due to strong &quot;hydrophobizing effect&quot;. For examples, 10 mM Ca2+, 10 mM Mg2+ and 10 mg/L poly-l-lysine enhanced the deposition rates to nearly 3, 2 and 4 times, as well as reduced the softness of deposited layer to almost 35%, 60% and 35%. Conversely, 10 mg/L negatively charged alginate might cause water retainment and steric shielding, thereby reducing the deposition rates to 40% and increasing the softness of deposited film to 120%. The presence of EPS sub-fractions can modify surface properties of sludge particles, to distinct degrees, contributing to biofilm formation. Notably, compared to tightly bound EPS (TB-EPS), loosely bound EPS (LB-EPS) was more conducive to microbial attachment, but the presence of LB-EPS promoted the formation of a soft layer on a hydrophobic surface. Overall, these results provide insights into intrinsic mechanisms of the variation of deposition rates and viscoelastic properties responding to critical factors, which are meaningful to predict and regulate the initial adhesion process in biofilm-based reactors.},
}
@article {pmid32417469,
year = {2020},
author = {Guo, L and Wang, J and Gou, Y and Tan, L and Liu, H and Pan, Y and Zhao, Y},
title = {Comparative proteomics reveals stress responses of Vibrio parahaemolyticus biofilm on different surfaces: Internal adaptation and external adjustment.},
journal = {The Science of the total environment},
volume = {731},
number = {},
pages = {138386},
doi = {10.1016/j.scitotenv.2020.138386},
pmid = {32417469},
issn = {1879-1026},
abstract = {Vibrio parahaemolyticus is a kind of gram-negative marine pathogen, which usually adheres to stainless steel (SS), glass (GS) and other abiotic surfaces in aquaculture and food processing in the form of biofilm and causes the spread of gastrointestinal illness. However, the deeply survival adaptation mechanism of V. parahaemolyticus biofilm cells on these contact surface remained unclear. Here, proteomics was used to investigated the physiological response of the V. parahaemolyticus biofilms cells to different abiotic surfaces (SS, GS and polystyrene (PS)). In addition, the effect of contact materials on the physical-chemical properties of biofilms are also characterized. Results showed that the expression of proteins of biofilm cells established on the SS surface were mainly related to the alleviation of metal ion stress and toxicity. The up-regulated proteins in the biofilm cells formed on the GS surface were mainly involved in the biological processes of sugar uptake, protein synthesis and bacterial chemotaxis. Meanwhile, the significantly expressed proteins in the biofilm cells formed on the PS surface were mainly involved in the cellular physiological activity of aromatic compound metabolism, osmotic stress and nutrient transport. All functional proteins mentioned above were closely related to the interaction characteristics of the contact surface and biofilm. This study provided an in-depth comparison of V. parahaemolyticus biofilm formation on these three abiotic surfaces, and presented a model in first time for the adaptation behavior of biofilm cells on different surfaces as affected by metal ion stress, nutrition, osmotic stress, and sugar utilization, which could facilitate an efficient control strategy for biofilm formation in industrial field.},
}
@article {pmid32417365,
year = {2020},
author = {Pejčić, M and Stojanović-Radić, Z and Genčić, M and Dimitrijević, M and Radulović, N},
title = {Anti-virulence potential of basil and sage essential oils: Inhibition of biofilm formation, motility and pyocyanin production of Pseudomonas aeruginosa isolates.},
journal = {Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association},
volume = {141},
number = {},
pages = {111431},
doi = {10.1016/j.fct.2020.111431},
pmid = {32417365},
issn = {1873-6351},
abstract = {The effects of basil (Ocimum basilicum) and sage (Salvia officinalis) essential oils on selected virulence factors (biofilm formation, mature biofilm resistance, motility, and pyocyanin production) of Pseudomonas aeruginosa clinical isolates were evaluated in the present study for the first time. The two essential oils were chemically characterized by GC and GC-MS analyses. Linalool and (E)-anethole were found to be the main components of the investigated basil oil, while α-thujone and camphor were the major constituents of the studied sage essential oil. The oils inhibited biofilm formation up to 99.9% vs control, and significant reductions (74.7-99.9%) were also noted when the oils were applied to mature biofilms. Likewise, swimming, swarming, and twitching motility patterns were highly affected by both oils. The basil and sage oils reduced pyocyanin production by 13.32-55.6% and 5.0-58.7%, respectively. Thus, basil and sage essential oils are potentially highly efficient antipseudomonal agents that could be used against both acute and chronic infections.},
}
@article {pmid32417013,
year = {2020},
author = {Luo, W and Huang, Y and Zhou, X and Han, Q and Peng, X and Ren, B and Li, J and Li, M and Cheng, L},
title = {The effect of disaggregated nano-hydroxyapatite on oral biofilm in vitro.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {36},
number = {7},
pages = {e207-e216},
doi = {10.1016/j.dental.2020.04.005},
pmid = {32417013},
issn = {1879-0097},
abstract = {OBJECTIVE: Agglomeration is a common problem facing the preparation and application of nanomaterials, and whether nano-hydroxyapatite (nano HA) can modulate oral microecology left to be unclear. In this study, nano HA was disaggregated by sodium hexametaphosphate (SHMP) and ultrasonic cavitation to observe whether agglomeration would affect its effect on oral bacterial biofilm.<br><br>METHODS: Dynamic light scattering (DLS) and scanning electronic microscope (SEM) were used to observe the treatment solutions. Single-species biofilms and multi-species biofilms were treated with 10% nano HA, 10% disaggregated nano HA, 10% micro hydroxyapatite (micro HA) and deionized water (DDW) for 30min and analyzed via MTT assay, lactic acid measurement, SEM and confocal laser scanning microscope (CLSM). Real-time polymerase chain reaction was performed to analyze the biofilm composition.<br><br>RESULTS: Ultrasonic cavitation combined with SHMP could significantly reduce the degree of agglomeration of nano HA. Disaggregated nano HA could inhibit bacterial growth and reduce the ability of bacterial biofilm to produce lactic acid and extracellular polysaccharides. There was no significant difference on composition of multi-species biofilms between nano HA and disaggregated nano HA.<br><br>SIGNIFICANCE: The disaggregated nano-hydroxyapatite could inhibit the metabolism and acid production of oral bacterial biofilm, but did not significantly affect the composition of multi-species biofilms.},
}
@article {pmid32416355,
year = {2020},
author = {Rahman, APH and Dash, S and Mohanty, PS and Mishra, A and Lundborg, CS and Tripathy, SK},
title = {Sonophotocatalytic disinfection of Shigella species under visible light irradiation: Insights into its molecular mechanism, antibacterial resistance and biofilm formation.},
journal = {Environmental research},
volume = {187},
number = {},
pages = {109620},
doi = {10.1016/j.envres.2020.109620},
pmid = {32416355},
issn = {1096-0953},
abstract = {Microbial contamination of water is one of the major sources of many diseases worldwide. Evolution of antibacterial resistance (ABR) alongside the caveats in most of the water treatment methods causes the severity of the current problem extremely vexing. This calls for an urgent need to develop new treatment methods aiming to reduce the microbial as well as ABR load in the environment. Herein, we successfully developed a visible light assisted sonophotocatalysis (SPC) using Fe/ZnO nanoparticles (NPs) for the disinfection of Shigella dysenteriae. A consortia containing S. dysenteriae and S. flexineri was also completely disinfected using SPC. Growth conditions of S. dysenteriae like growth phases and growth temperaturehad different outcomes on the overall efficacy of SPC. Compared with catalysts such as ZnO and TiO2, Fe/ZnO resulted in better disinfection. Multi-ROS production, mostly containing h+ and O2· radicals, due to the electron displacement in the catalyst and acoustic cavitation was identified as the factors behind bacterial lethality. The ROS produced was found to interfere with the metabolic activities of S. dysenteriae by causing membrane perturbation. We identified DNA damage inside the cells and the subsequent release of intracellular components. The compositional changes in the fatty acid makeup of the cells were altered as a result of SPC and few fatty acid markers indicating the stress posed by SPC were also identified. Loss of ABR in S. dysenteriae was also recorded post SPC treatment. Abatement in the biofilm forming ability of the injured bacterial cells was also recorded, proving the extremity of stress induced by SPC. Hence, the excellent efficacy of SPC in disinfecting bacteria is proposed for tertiary water treatment applications.},
}
@article {pmid32416351,
year = {2020},
author = {Tantivitayakul, P and Kaypetch, R and Muadchiengka, T},
title = {Thymoquinone inhibits biofilm formation and virulence properties of periodontal bacteria.},
journal = {Archives of oral biology},
volume = {115},
number = {},
pages = {104744},
doi = {10.1016/j.archoralbio.2020.104744},
pmid = {32416351},
issn = {1879-1506},
abstract = {OBJECTIVES: To evaluate the effects of thymoquinone (TQ) on biofilm formation, hemolysis, hydrogen sulfide (H2S) production and expression of virulence factors of Fusobacterium nucleatum and Porphyromonas gingivalis.<br><br>MATERIALS AND METHODS: Reference strains of F. nucleatum ATCC 25586 and P. gingivalis A7436 were tested in our study. The minimum inhibitory concentration (MIC) of TQ was determined by broth microdilution method. The impacts of TQ on virulence properties of the periodontal bacteria including biofilm formation, hemolysis and H2S activities were studied. Quantitative RT-PCR was performed to evaluate the expression levels of key virulence factors including outer membrane proteins (aim-1, fadA) in F. nucleatum as well as cysteine proteinases or gingipains (rgpA, rgpB, kgp) and fimbriae (fimA, mfa1) in P. gingivalis.<br><br>RESULTS: The MIC of TQ were 12.5 and 1.56 μg/mL in F. nucleatum and P. gingivalis, respectively. The sub-MIC concentrations of TQ could prevent biofilm formation and hemolysis activities of both bacteria. TQ also inhibited H2S production which is highly associated with oral malodour. Scanning electron microscopy revealed that TQ could disrupt bacterial membrane and led to cell lysis. Furthermore, TQ reduced the expression of major virulence factors tested in F. nucleatum and P. gingivalis.<br><br>CONCLUSIONS: The TQ had potent antibacterial effect and could attenuate virulence properties of F. nucleatum and P. gingivalis. Therefore, TQ has the potential to be developed and used in periodontal treatments, especially to prevent the progression of periodontitis.},
}
@article {pmid32415949,
year = {2020},
author = {Zhang, L and Jin, M and Sun, M},
title = {Inhibition characteristics of biofilm structure of Staphylococcus aureus.},
journal = {Cellular and molecular biology (Noisy-le-Grand, France)},
volume = {66},
number = {2},
pages = {204-211},
pmid = {32415949},
issn = {1165-158X},
abstract = {Different extracts have different effects on the biofilm structure of Staphylococcus aureus, and the biofilm structure of Staphylococcus aureus will produce different inhibition reactions. In this study, different experimental reagent extracts were used to analyze the inhibition characteristics of Staphylococcus aureus biofilm structure. The inhibition characteristics of bacterial biofilm structure were obtained by using the same bacteria species and the same experimental environment. The results showed that the chloroform extract had a good inhibitory effect on the biofilm structure, which could effectively inhibit the formation of biofilm; the acetic acid extract had an impact on the formation of biofilm, which was destructive to the biofilm; the petroleum ether extract had no effect on the formation of biofilm, that is, it had no inhibitory effect.},
}
@article {pmid32415612,
year = {2020},
author = {Iseppi, R and Feminò, R and Sabia, C and Messi, P},
title = {Evaluation of Bacterial Biofilm Removal Properties of MEDSTER 2000 Cold Sterilant on Different Materials.},
journal = {Advances in experimental medicine and biology},
volume = {},
number = {},
pages = {},
doi = {10.1007/5584_2020_542},
pmid = {32415612},
issn = {0065-2598},
abstract = {We studied the antibacterial and anti-biofilm properties of MEDSTER 2000, a pH neutral biodegradable mixed acidic peroxide disinfectant belonging to the class IIb medical device which has been designed for decontamination and cold sterilization of hospital instruments. The broth microdilution method was used to define the antibacterial activity against planktonic form of both classified bacteria and antibiotic resistant strains of clinical source, whereas effectiveness toward their biofilm was determined on mature biofilm, grown both on plastic and stainless steel surfaces. The results showed that for the planktonic form the antibacterial activity of MEDSTER 2000 was already observed after 10 min at the lowest concentration (0.1%), and this effect was not exposure-and/or concentration-dependent. After the same time of exposure at the concentration of 2% the disinfectant was able to completely eradicate all tested bacteria grown in sessile form on both surfaces, with a greater than 6 log CFU/cm2 reduction in viable cells. This result is supported by the microscope observation by crystal violet and live/dead assays. For the high antibacterial and anti-biofilm ability emerged, MEDSTER 2000 could represent a new and more effective approach for semicritical devices that need a high-level disinfection and could not sustain the process of heat sterilization.},
}
@article {pmid32415320,
year = {2020},
author = {Benedek, T and Szentgyörgyi, F and Szabó, I and Farkas, M and Duran, R and Kriszt, B and Táncsics, A},
title = {Aerobic and oxygen-limited naphthalene-amended enrichments induced the dominance of Pseudomonas spp. from a groundwater bacterial biofilm.},
journal = {Applied microbiology and biotechnology},
volume = {104},
number = {13},
pages = {6023-6043},
pmid = {32415320},
issn = {1432-0614},
support = {PD 128831//Nemzeti Kutatási Fejlesztési és Innovációs Hivatal/ ; ÚNKP-19-3-I//New National Excellence Program of the Ministry of Innovation and Technology/ ; NKFIH-1159-6/2019//Higher Education Institutional Excellence Program awarded by the Ministry of Human Capacities/ ; },
abstract = {In this study, we aimed at determining the impact of naphthalene and different oxygen levels on a biofilm bacterial community originated from a petroleum hydrocarbon-contaminated groundwater. By using cultivation-dependent and cultivation-independent approaches, the enrichment, identification, and isolation of aerobic and oxygen-limited naphthalene degraders was possible. Results indicated that, regardless of the oxygenation conditions, Pseudomonas spp. became the most dominant in the naphthalene-amended selective enrichment cultures. Under low-oxygen conditions, P. veronii/P. extremaustralis lineage affiliating bacteria, and under full aerobic conditions P. laurentiana-related isolates were most probably capable of naphthalene biodegradation. A molecular biological tool has been developed for the detection of naphthalene 1,2-dioxygenase-related 2Fe-2S reductase genes of Gram-negative bacteria. The newly developed COnsensus DEgenerate Hybrid Oligonucleotide Primers (CODEHOP-PCR) technique may be used in the monitoring of the natural attenuation capacity of PAH-contaminated sites. A bacterial strain collection with prolific biofilm-producing and effective naphthalene-degrading organisms was established. The obtained strain collection may be applicable in the future for the development of biofilm-based bioremediation systems for the elimination of PAHs from groundwater (e.g., biofilm-based biobarriers).},
}
@article {pmid32415073,
year = {2020},
author = {Bamford, NC and Le Mauff, F and Van Loon, JC and Ostapska, H and Snarr, BD and Zhang, Y and Kitova, EN and Klassen, JS and Codée, JDC and Sheppard, DC and Howell, PL},
title = {Structural and biochemical characterization of the exopolysaccharide deacetylase Agd3 required for Aspergillus fumigatus biofilm formation.},
journal = {Nature communications},
volume = {11},
number = {1},
pages = {2450},
pmid = {32415073},
issn = {2041-1723},
support = {Vanier//Gouvernement du Canada | Natural Sciences and Engineering Research Council of Canada (Conseil de Recherches en Sciences Naturelles et en Génie du Canada)/ ; CGS-M//Gouvernement du Canada | Natural Sciences and Engineering Research Council of Canada (Conseil de Recherches en Sciences Naturelles et en Génie du Canada)/ ; Studentship//Cystic Fibrosis Canada (Fibrose kystique Canada)/ ; 81361//Gouvernement du Canada | Canadian Institutes of Health Research (Instituts de Recherche en Santé du Canada)/ ; 123306//Gouvernement du Canada | Canadian Institutes of Health Research (Instituts de Recherche en Santé du Canada)/ ; FDN-159902//Gouvernement du Canada | Canadian Institutes of Health Research (Instituts de Recherche en Santé du Canada)/ ; 81361//Gouvernement du Canada | Canadian Institutes of Health Research (Instituts de Recherche en Santé du Canada)/ ; FDN-154327//Gouvernement du Canada | Canadian Institutes of Health Research (Instituts de Recherche en Santé du Canada)/ ; 43998//Gouvernement du Canada | Canadian Institutes of Health Research (Instituts de Recherche en Santé du Canada)/ ; Distinguished Research Scholar//Fonds de Recherche du Québec - Santé (Fonds de la recherche en sante du Quebec)/ ; },
abstract = {The exopolysaccharide galactosaminogalactan (GAG) is an important virulence factor of the fungal pathogen Aspergillus fumigatus. Deletion of a gene encoding a putative deacetylase, Agd3, leads to defects in GAG deacetylation, biofilm formation, and virulence. Here, we show that Agd3 deacetylates GAG in a metal-dependent manner, and is the founding member of carbohydrate esterase family CE18. The active site is formed by four catalytic motifs that are essential for activity. The structure of Agd3 includes an elongated substrate-binding cleft formed by a carbohydrate binding module (CBM) that is the founding member of CBM family 87. Agd3 homologues are encoded in previously unidentified putative bacterial exopolysaccharide biosynthetic operons and in other fungal genomes.},
}
@article {pmid32414689,
year = {2020},
author = {Iwahashi, J and Kamei, K and Watanabe, H},
title = {Disruption of Aspergillus fumigatus biofilm by Streptococcus pneumoniae: Mycelial fragmentation by hydrogen peroxide.},
journal = {Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy},
volume = {26},
number = {8},
pages = {831-837},
doi = {10.1016/j.jiac.2020.03.015},
pmid = {32414689},
issn = {1437-7780},
abstract = {Biofilm is a complex structure consisting of microorganisms such as bacteria, fungi and an extracellular matrix (ECM). Biofilms are involved in most microbial infections and show persistent resistance to antibiotic treatment and immune response. Both Aspergillus fumigatus and Streptococcus pneumoniae are colonizers that can form biofilms in the respiratory tract. These pathogens have been simultaneously isolated from the same patient, but their interaction is poorly understood. We observed morphological changes in single- and mixed-species biofilms prepared for confocal laser scanning microscopy and scanning electron microscopy (SEM). Pneumococci suppressed the development of a fungal biofilm, and it even disrupted a preformed fungal biofilm. When a preformed fungal biofilm was treated with pneumococci, the mycelial network was fragmented, and only bacteria could develop. SEM revealed that the fragmented mycelium was further disrupted into fine filaments as treatment time progressed, and that the ECM of the preformed fungal biofilm had disappeared. The pneumococcal culture supernatant contained mycelial fragmentation activity that was heat-sensitive. The culture supernatant of a mutant pneumococcal strain deficient in pneumolysin (Δply) also exhibited the mycelial fragmentation activity. Enolase and lactate oxidase, which are involved in glycolysis and hydrogen peroxide production, were identified in the culture supernatant of the Δply mutant. Neither the wild type nor the mutant strain could fragment the mycelium in the presence of catalase. These data suggest that hydrogen peroxide could fragment the mycelium and would terminate the co-existence of A. fumigatus and S. pneumoniae in biofilm.},
}
@article {pmid32413811,
year = {2020},
author = {Arun, D and Vimala, R and Devendranath Ramkumar, K},
title = {Investigating the microbial-influenced corrosion of UNS S32750 stainless-steel base alloy and weld seams by biofilm-forming marine bacterium Macrococcus equipercicus.},
journal = {Bioelectrochemistry (Amsterdam, Netherlands)},
volume = {135},
number = {},
pages = {107546},
doi = {10.1016/j.bioelechem.2020.107546},
pmid = {32413811},
issn = {1878-562X},
abstract = {This study investigates the microbial-influenced corrosion of UNS S32750 super-duplex stainless-steel joints fabricated using different welding methods. Herein, the samples were introduced into a medium inoculated with Macrococcus equipercicus isolated from a marine environment. Confocal laser scanning microscopy and atomic force microscopy were used to characterise the topography and formation of pits in the corroded samples, respectively. Potentiodynamic polarisation studies were conducted on both the base alloy and weld seams exposed for 30 and 60 days in the experimental system inoculated with M. equipercicus and un-inoculated system. Results indicate that the thickness of the biofilm formed due to this bacterium increased and became heterogeneous with an increase in the exposure time, thereby resulting in micro-pits. Bacterial colonisation was observed in all the coupons after exposure to the inoculated medium. Although micro-pits were observed in all the coupons, the base metal and flux-cored arc weld seams showed highest sensitivity to bacterial attack.},
}
@article {pmid32413575,
year = {2020},
author = {Patel, M and Srivastava, V and Ahmad, A},
title = {Dodonaea viscosa var angustifolia derived 5,6,8-trihydroxy-7,4' dimethoxy flavone inhibits ergosterol synthesis and the production of hyphae and biofilm in Candida albicans.},
journal = {Journal of ethnopharmacology},
volume = {259},
number = {},
pages = {112965},
doi = {10.1016/j.jep.2020.112965},
pmid = {32413575},
issn = {1872-7573},
abstract = {Candida albicans is developing resistance to existing drugs increasing morbidity and mortality, which elevates an immediate need to explore new antifungal agents. Phytochemicals are an excellent source of therapeutic agents. We previously reported the antifungal activity of the crude extract of Dodonaea viscosa var. angustifolia Jacq. (DVA) from which a beneficial compound flavone: 5,6,8-trihydroxy-7,4' dimethoxy flavone (5,6,8-trihydroxy-7-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one) abbreviated as TMMC, was extracted.<br><br>AIM OF THE STUDY: The present study evaluated the effect of a TMMC subfraction on biofilms, membrane stability, ergosterol biosynthesis and germ tube (GT) formation in Candida albicans.<br><br>MATERIALS AND METHODS: Extracts were prepared and fractionated to obtain purified TMMC. Minimum inhibitory concentrations of TMMC were obtained and subinhibitory concentrations were selected for further studies. Confocal laser scanning microscopy (CLSM) was performed to assess the effect of TMMC on membrane permeability and sterol deposition using propidium iodide (PI) and filipin stains, respectively.<br><br>RESULTS: Minimum inhibitory concentrations (MIC) and Minimum Fungicidal concentrations (MFC) of TMMC were 0.39 mg/mL and 1.56 mg/mL, respectively. TMMC inhibited biofilm formation and damaged mature biofilms at 0.39 mg/mL and 1.56 mg/mL, respectively. CLSM further confirmed the disruption and architectural changes in biofilms following treatment with TMMC. TMMC also inhibited GT formation and ergosterol biosynthesis in a concentration dependent manner, which was further confirmed by varying sterol distribution and membrane disruption in treated and untreated cells.<br><br>CONCLUSIONS: With the multiple targets at different concentrations, TMMC warrants its potential use as antifungal drug against C. albicans. However further studies using animal models and more mechanistic approaches will be required.},
}
@article {pmid32410574,
year = {2020},
author = {Peng, N and Cai, P and Mortimer, M and Wu, Y and Gao, C and Huang, Q},
title = {The exopolysaccharide-eDNA interaction modulates 3D architecture of Bacillus subtilis biofilm.},
journal = {BMC microbiology},
volume = {20},
number = {1},
pages = {115},
pmid = {32410574},
issn = {1471-2180},
support = {2016YFD0800206//National Basic Research Program of China (973 Program)/ ; 41877029//National Natural Science Foundation of China/ ; NAF\R1\191017//Royal Society-Newton Advanced Fellowship/ ; 2016YFD0800206//National Key Research Program of China/ ; 2019020701011469//Wuhan Science and Technology Bureau/ ; },
abstract = {BACKGROUND: Bacterial biofilms are surface-adherent microbial communities in which individual cells are surrounded by a self-produced extracellular matrix of polysaccharides, extracellular DNA (eDNA) and proteins. Interactions among matrix components within biofilms are responsible for creating an adaptable structure during biofilm development. However, it is unclear how the interactions among matrix components contribute to the construction of the three-dimensional (3D) biofilm architecture.<br><br>RESULTS: DNase I treatment significantly inhibited Bacillus subtilis biofilm formation in the early phases of biofilm development. Confocal laser scanning microscopy (CLSM) and image analysis revealed that eDNA was cooperative with exopolysaccharide (EPS) in the early stages of B. subtilis biofilm development, while EPS played a major structural role in the later stages. In addition, deletion of the EPS production gene epsG in B. subtilis SBE1 resulted in loss of the interaction between EPS and eDNA and reduced the biofilm biomass in pellicles at the air-liquid interface. The physical interaction between these two essential biofilm matrix components was confirmed by isothermal titration calorimetry (ITC).<br><br>CONCLUSIONS: Biofilm 3D structures become interconnected through surrounding eDNA and EPS. eDNA interacts with EPS in the early phases of biofilm development, while EPS mainly participates in the maturation of biofilms. The findings of this study provide a better understanding of the role of the interaction between eDNA and EPS in shaping the biofilm 3D matrix structure and biofilm formation.},
}
@article {pmid32409992,
year = {2020},
author = {Tak, S and Tiwari, A and Vellanki, BP},
title = {Identification of emerging contaminants and their transformation products in a moving bed biofilm reactor (MBBR)-based drinking water treatment plant around River Yamuna in India.},
journal = {Environmental monitoring and assessment},
volume = {192},
number = {6},
pages = {365},
doi = {10.1007/s10661-020-08303-4},
pmid = {32409992},
issn = {1573-2959},
support = {933-CED//NBCC/ ; },
mesh = {Biofilms ; *Bioreactors ; Environmental Monitoring ; India ; Rivers ; *Water Pollutants, Chemical ; *Water Purification ; },
abstract = {The prevalence of emerging contaminants of concern in water regimes is very common these days. High anthropogenic intervention is leading to occurrence of various types of microcontaminants of concern in drinking water systems. Their removal using conventional form of treatment systems employed in water treatment plants is not widely researched upon. Their fate in the conventional as well as advanced water treatment system needs to be focused upon for efficient and safe water disposal. Some compounds may leave the system unchanged or some might transform into much more toxic byproduct. Moreover, understanding level of occurrence of these emerging contaminants in source water bodies is also quintessential for assessing their fate in treatment plant itself as well as in the final treated water. Here in this study, the occurrence and removal of various classes of emerging contaminants were investigated in a moving bed biofilm reactor (MBBR)-based advanced drinking water treatment plant (ADWTP) alongside one conventional drinking water treatment plant, both of which use River Yamuna as the source of water. Non-target analysis utilizing high-performance liquid chromatography combined with time of flight (HPLC-QToF) identified more than 300 compounds. Pharmaceuticals accounted for a major fraction (58%) of the identified compounds, followed by plasticizers and insecticides. Nine parent compound and their transformation products were additionally identified using solid-phase extraction followed by analysis using gas chromatography mass spectrometry and HPLC-QToF. The degradation pathway of the parent compounds in MBBR-based ADWTP was also analyzed in depth. The efficiency of each unit process of MBBR-based drinking water treatment plant was studied in terms of removal of few emerging contaminants. Pharmaceutical compound like diclofenac supposedly was persistent, even, toward the end of the treatment train. Semi-quantitative analysis revealed ineffective removal of pyridine, hydrochlorothiazide, and diethyl phthalate in the outlet of ADWTP. ADWTP was able to remove a few emerging contaminants, but a few were recalcitrant. Likewise, it was established that although some parent compounds were degraded, much more toxic transformation products were formed and were prevalent at the end of the treatment.},
}
@article {pmid32409853,
year = {2020},
author = {Saygin, H and Baysal, A},
title = {Biofilm Formation of Clinically Important Bacteria on Bio-Based and Conventional Micro/Submicron-Sized Plastics.},
journal = {Bulletin of environmental contamination and toxicology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00128-020-02876-z},
pmid = {32409853},
issn = {1432-0800},
abstract = {Micron/submicron-sized plastic debris in the environment is a global issue of increasing concern and may harm human health. A large number of studies have shown that plastic debris has various toxicological effects on different organisms. Thus, efforts have increased to replace conventional plastics with bioplastics. However, investigations on the relation of submicron-sized bioplastics- and conventional plastics to culture-dependent biofilm formation and their similarities and discrepancies are still very limited. For this purpose, two end products made from bioplastics and their equivalent end products from conventional plastics were used to examine the response of the biofilm formation of selected clinically important bacteria. To evaluate the similarities and differences of submicron-sized bioplastics and conventional plastics on biofilm formation, the physicochemistry (particle size, zeta potential, chemical composition, and surface chemistry) of the tested plastics was examined, as well as the characteristics of the biofilms (categorization, protein/carbohydrate).},
}
@article {pmid32408616,
year = {2020},
author = {Naclerio, GA and Onyedibe, KI and Sintim, HO},
title = {Lipoteichoic Acid Biosynthesis Inhibitors as Potent Inhibitors of S. aureus and E. faecalis Growth and Biofilm Formation.},
journal = {Molecules (Basel, Switzerland)},
volume = {25},
number = {10},
pages = {},
pmid = {32408616},
issn = {1420-3049},
support = {N/A//Purdue University/ ; },
abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE) have been deemed as serious threats by the CDC. Many chronic MRSA and VRE infections are due to biofilm formation. Biofilm are considered to be between 10-10,000 times more resistant to antibiotics, and therefore new chemical entities that inhibit and/or eradicate biofilm formation are needed. Teichoic acids, such as lipoteichoic acids (LTAs) and wall teichoic acids (WTAs), play pivotal roles in Gram-positive bacteria's ability to grow, replicate, and form biofilms, making the inhibition of these teichoic acids a promising approach to fight infections by biofilm forming bacteria. Here, we describe the potent biofilm inhibition activity against MRSA and VRE biofilms by two LTA biosynthesis inhibitors HSGN-94 and HSGN-189 with MBICs as low as 0.0625 µg/mL against MRSA biofilms and 0.5 µg/mL against VRE biofilms. Additionally, both HSGN-94 and HSGN-189 were shown to potently synergize with the WTA inhibitor Tunicamycin in inhibiting MRSA and VRE biofilm formation.},
}
@article {pmid32408121,
year = {2020},
author = {Yuan, L and Lyu, P and Huang, YY and Du, N and Qi, W and Hamblin, MR and Wang, Y},
title = {Corrigendum to &quot;Potassium iodide enhances the photobactericidal effect of methylene blue on Enterococcus faecalis as planktonic cells and as biofilm infection in teeth&quot; [J Photochem Photobiol B 203(2020) 1-11/111730].},
journal = {Journal of photochemistry and photobiology. B, Biology},
volume = {207},
number = {},
pages = {111892},
doi = {10.1016/j.jphotobiol.2020.111892},
pmid = {32408121},
issn = {1873-2682},
}
@article {pmid32408033,
year = {2020},
author = {Zhu, C and Mahmood, Z and Zhang, W and Akram, MW and Ainur, D and Ma, H},
title = {In situ investigation of acute exposure of graphene oxide on activated sludge: Biofilm characteristics, microbial activity and cytotoxicity.},
journal = {Ecotoxicology and environmental safety},
volume = {199},
number = {},
pages = {110639},
doi = {10.1016/j.ecoenv.2020.110639},
pmid = {32408033},
issn = {1090-2414},
abstract = {Graphene Oxide (GO) has wide applications in many fields which has caused a large expected quantity of the graphene-based wastes. It is necessary to understand the toxic effects of the GO on the activated sludge (AS) considering its inevitable discharge to the wastewater treatment plants as the ultimate repositories for these wastes. In this study, the acute exposures of the multilayer Nano-graphene oxide (MNGO) at different dosages were conducted in order to investigate its integrated effects on the formation of the biofilm, mature biofilm and the microbial activity of the activated sludge. Raman spectroscopy and laser scanning confocal microscopy (LSCM) were adopted for the in-situ characterization of the biofilm with the exposure of the MNGO. The results showed that the activated sludge was tolerable to the acute exposure of the less than 100 mg/L of the MNGO, especially for the mature biofilm, and only a subtle decrease was found in the size and thickness during the formation of the biofilm, while the amount of 300 mg/L of the MNGO caused the sever deterioration on the activated sludge system. The microbial metabolic activity, viability, and the biological removal of the nutrients were significantly affected with the more than 100 mg/L of the MNGO. It was also demonstrated by the microbial cytotoxicity tests that the increase in the exposure of the MNGO was related to the increase in the reactive oxygen species (ROS) and the damaging degree of the cell membrane.},
}
@article {pmid32407890,
year = {2020},
author = {Nie, M and Deng, DM and Wu, Y and de Oliveira, KT and Bagnato, VS and Crielaard, W and Rastelli, ANS},
title = {Photodynamic inactivation mediated by methylene blue or chlorin e6 against Streptococcus mutans biofilm.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {101817},
doi = {10.1016/j.pdpdt.2020.101817},
pmid = {32407890},
issn = {1873-1597},
abstract = {BACKGROUND: An appropriate photosensitizer (PS) for photodynamic inactivation should have a pronounced antimicrobial efficacy but low dark toxicity. The aim of this study is to investigate the concentration-dependent antimicrobial efficacies of methylene blue (MB) and chlorin e6 (Ce6), against Streptococcus mutans biofilms and to compare the efficacies of these two PSs.<br><br>METHODS: The 48-h S. mutans UA159 biofilms, grown on glass coverslips, were subjected to MB or Ce6 at 25, 50, 100 and 200 μM with or without irradiation by 660 nM LED light (L). Control groups (-PS-L and -PS + L) were also included. Viability of the biofilm was analyzed by CFU/biofilm and biofilm lactic acid production was quantified by an enzymatic assay.<br><br>RESULTS: With irradiation, MB under 25 μM resulted in 2-log reduction in biofilm viability and 30-fold reduction in biofilm lactic acid production. However, this biofilm killing efficacy did not change with increasing MB concentration. The biofilm killing efficacy of Ce6 increased with increasing Ce6 concentrations and resulted in 5-log reduction in biofilm viability. The lactic acid inhibitory effect of Ce6 was significantly lower than MB at 25 μM (p<0.01) but higher than MB at 200 μM (p=0.05), although the difference at 200 μM did not reach statistical significance. No dark toxicity could be observed for MB whereas low dark toxicity could be seen for Ce6 when the concentration is above 50 μM.<br><br>CONCLUSION: Ce6 under 200 μM showed to be more powerful PS for photodynamic inactivation than MB. Both Ce6- and MB-based photodynamic inactivation are useful methods for biofilm control in caries prevention.},
}
@article {pmid32407475,
year = {2020},
author = {Sánchez-Herrera, R and Flores-Villavicencio, LL and Pichardo-Molina, JL and Castruita-Domínguez, JP and Aparicio-Fernández, X and Sabanero López, M and Villagómez-Castro, JC},
title = {Analysis of biofilm formation by Sporothrix schenckii.},
journal = {Medical mycology},
volume = {},
number = {},
pages = {},
doi = {10.1093/mmy/myaa027},
pmid = {32407475},
issn = {1460-2709},
abstract = {The development of mature biofilms is an aid in numerous aspects of the life cycle of fungi. It is well known that Sporothrix schenckii complex causes a benign subcutaneous mycosis, but recent studies have suggestedthat biofilm formation may be one of the important factors involved in its virulence. Here we report the study of the biomass organization and a model of the stages of S. schenckii biofilm development: adsorption, active adhesion, microcolony formation, maturation, and dispersal of biofilm fragments. During the development, the biofilm is surrounded by extracellular matrix, which contains glycoprotein (mannose rich), carbohydrates, lipids, and nucleic acid. In addition, the extracellular DNA increases in extracellular matrix as a key component to structural integrity and antifungal resistance. The study of S. schenckii biofilm contributes to a better understanding of growth biofilm and physiology, adding new insights into the mechanisms of virulence and persistence of pathogenic microorganisms.},
}
@article {pmid32407362,
year = {2020},
author = {Pestrak, MJ and Gupta, TT and Dusane, DH and Guzior, DV and Staats, A and Harro, J and Horswill, AR and Stoodley, P},
title = {Correction: Investigation of synovial fluid induced Staphylococcus aureus aggregate development and its impact on surface attachment and biofilm formation.},
journal = {PloS one},
volume = {15},
number = {5},
pages = {e0233534},
pmid = {32407362},
issn = {1932-6203},
support = {R01 GM124436/GM/NIGMS NIH HHS/United States ; },
abstract = {[This corrects the article DOI: 10.1371/journal.pone.0231791.].},
}
@article {pmid32404511,
year = {2020},
author = {Chakraborty, T and Tóth, Z and Tóth, R and Vágvölgyi, C and Gácser, A},
title = {Iron Metabolism, Pseudohypha Production, and Biofilm Formation through a Multicopper Oxidase in the Human-Pathogenic Fungus Candida parapsilosis.},
journal = {mSphere},
volume = {5},
number = {3},
pages = {},
pmid = {32404511},
issn = {2379-5042},
abstract = {Among all the essential micronutrients, iron plays an important role in mammalian biology. It is also essential for pathogens infecting mammalian hosts, including bacteria, fungi, and protozoans. As the availability of accessible iron is limited within the mammalian host, several human-pathogenic fungal pathogens, such as Candida albicans, Cryptococcus neoformans, Candida glabrata, and Aspergillus fumigatus, have developed various iron uptake mechanisms. Although Candida parapsilosis is the second or third most common non-albicans Candida species associated with systemic and superficial Candida infections in immunocompromised patients, the mechanisms of iron uptake and homoeostasis remain unknown in this fungus. In the current report, we show that a homologue of the multicopper oxidase gene FET3 is present in the genome of C. parapsilosis (CPAR2_603600) and plays a significant role in iron acquisition. We found that homozygous deletion mutants of CPAR2_603600 showed defects under low-iron conditions and were also sensitive to various stressors. Our results also revealed that the levels of pseudohypha formation and biofilm formation were reduced in the null mutants compared to the wild type. This phenotypic defect could be partially rescued by supplementation with excess iron in the growth medium. The expression levels of the orthologues of various iron metabolism-related genes were also altered in the mutants compared to the parental strain. In conclusion, our report describes the role of CPAR2_603600 in iron homoeostasis maintenance as well as morphology and biofilm formation regulation in this pathogenic fungus.IMPORTANCEC. parapsilosis is the second or third most common opportunistic human-pathogenic Candida species, being responsible for severe fungal infections among immunocompromised patients, especially low-birth-weight infants (0 to 2 years of age). Among the major virulence factors that pathogenic fungi possess is the ability to compete with the host for essential micronutrients, including iron. Accessible iron is required for the maintenance of several metabolic processes. In order to obtain accessible iron from the host, pathogenic fungi have developed several iron acquisition and metabolic mechanisms. Although C. parapsilosis is a frequent cause of invasive candidiasis, little is known about what iron metabolic processes this fungus possesses that could contribute to the species' virulent behavior. In this study, we identified the multicopper oxidase FET3 gene that regulates iron homeostasis maintenance and also plays important roles in the morphology of the fungus as well as in biofilm formation, two additional factors in fungal virulence.},
}
@article {pmid32403300,
year = {2020},
author = {Madaha, EL and Gonsu, HK and Bughe, RN and Fonkoua, MC and Ateba, CN and Mbacham, WF},
title = {Occurrence of blaTEM and blaCTXM Genes and Biofilm-Forming Ability among Clinical Isolates of Pseudomonasaeruginosa and Acinetobacterbaumannii in Yaoundé, Cameroon.},
journal = {Microorganisms},
volume = {8},
number = {5},
pages = {},
pmid = {32403300},
issn = {2076-2607},
support = {0000//North-West University/ ; },
abstract = {BACKGROUND: Pseudomonas aeruginosa (PSA) and Acinetobacterbaumannii (ACB) are non-fermentative bacteria mostly associated with nosocomial infections in humans.<br><br>OBJECTIVE: This study aimed to determine the antimicrobial resistance profiles and virulence gene of PSA and ACB previously isolated from humans in selected health facilities in Yaoundé, Cameroon.<br><br>METHODS: A total of 77 and 27 presumptive PSA and ACB isolates, respectively, were collected from the Yaoundé teaching hospital. These isolates were previously isolated from various samples including pus, blood and broncho-alveolar lavage. The identities of the isolates were determined through polymerase chain reaction (PCR) amplification of PSA and ACB specific sequences. Antimicrobial susceptibility testing (AST) was performed using the Kirby-Bauer disc diffusion method. Phenotypical expression of AmpC β-lactamases (AmpC), extended spectrum β-lactamases (ESBLs) and metallo β-Lactamases (MBLs) were determined using the combined disc method. Bacterial genomes were screened for the presence of β-lactamases blaTEM and blaCTXM genes using specific PCR. The pathogenicity of PSA and ACB was assessed through amplification of the lasB,exoA,pslA and exoS as well as OmpA and csuE virulence genes, respectively.<br><br>RESULTS: Of the 77 presumptive PSA isolates, a large proportion (75 to 97.4%) were positively identified. All (100%) of the presumptive 27 ACB harbored the ACB-specific ITS gene fragment by PCR. Twenty five percent of the PSA isolates produced ESBLs phenotypically while more than 90% of these isolates were positive for the lasB,exoA,pslA and exoS genes. A large proportion (88%) of the ACB isolates harboured the OmpA and csuE genes. blaTEM and blaCTXM were detected in 17 and 4% of PSA, respectively, while a much higher proportion (70 and 29%) of the ACB isolates possessed these resistance determinants respectively.<br><br>CONCLUSION: Our findings reveal the occurrence of both virulence and drug-resistant determinants in clinical PSA and ACB isolates from patients in health care settings in Yaoundé, Cameroon, thus suggesting their role in the pathological conditions in patients.},
}
@article {pmid32403244,
year = {2020},
author = {Francis, F and Druart, F and Mavungu, JDD and De Boevre, M and De Saeger, S and Delvigne, F},
title = {Biofilm Mode of Cultivation Leads to an Improvement of the Entomotoxic Patterns of Two Aspergillus Species.},
journal = {Microorganisms},
volume = {8},
number = {5},
pages = {},
pmid = {32403244},
issn = {2076-2607},
abstract = {Two fungi, i.e., Aspergillus flavus Link and Aspergillus oryzae (Ahlb.) E. Cohn, were cultivated according to two methodologies, namely submerged and biofilm cultures with the primary aim to use their secondary metabolites the supernatant CL50, and CL90 varied between 1.3% (v/v) to 12.7% (v/v) for incubation times from 24 to 72 h. While the A. flavus supernatant entomotoxicity was higher than this of A. oryzae, the biofilm culture application increased the efficiency of the former. Proteomic analysis of the supernatants revealed discrepancies among the two species and modes of cultivation. Furthermore, the secondary metabolite profiles of both Aspergillus cultures were verified. Aspergillic acid, beta-cyclopiazonic acid, cyclopiazonic acid, ferrineospergillin, flavacol, and spermadin A were most predominant. Generally, these secondary metabolites were present in higher concentrations in the supernatants of A. flavus and biofilm cultures. These molecular identifications correlated positively with entomotoxic activity. Noteworthy, the absence of carcinogenic aflatoxins was remarkable, and it will allow further valorization to produce A. flavus to develop potential biopesticides.},
}
@article {pmid32403180,
year = {2020},
author = {Subh, L and Correa, W and Pinkvos, TJ and Behrens, P and Brandenburg, K and Gutsmann, T and Stiesch, M and Doll, K and Winkel, A},
title = {Synthetic anti-endotoxin peptides interfere with Gram-positive and Gram-negative bacteria, their adhesion and biofilm formation on titanium.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14701},
pmid = {32403180},
issn = {1365-2672},
support = {//Brandenburg Antiinfectiva GmbH/ ; //Volkswagen Foundation/ ; KF3382401CS4//Federal Ministry of Economic Affairs and Energy, Germany/ ; //Ministry of Economic Affairs/ ; },
abstract = {AIMS: Implant-associated infections arise from the formation of bacterial biofilms, which are difficult to be treated with conventional antibiotics. Therefore, there is a need for new implant functionalizations, which inhibit biofilm formation. The aim of the present study was to characterize the effect of synthetic peptides to assess their applicability for this purpose.<br><br>METHODS AND RESULTS: Two synthetic anti-endotoxin peptides, Pep19-2.5 and Pep19-4LF (Aspidasept I and II) were tested against both Gram-positive (Staphylococcus aureus and Streptococcus oralis) and Gram-negative (Pseudomonas aeruginosa and Aggregatibacter actinomycetemcomitans) bacteria associated with implant infections. Their activity was evaluated against different states of biofilm formation on the implant material titanium using CFU, live/dead fluorescence staining and confocal microscopy. Both peptides inhibited planktonic bacteria growth, impacted initial bacterial adhesion, reduced biofilm volume and increased the proportion of dead cells. Additionally, cytotoxicity analyses showed that neither peptide harmed human gingival fibroblasts nor osteoblasts at lower concentrations.<br><br>CONCLUSION: A concentration-dependent antibacterial activity of both peptides against biofilms of four clinically relevant bacteria could be demonstrated.<br><br>The results of this study serve as a promising basis for the improvement of these peptides in order to finally achieve a peptide-equipped antibacterial implant surface.},
}
@article {pmid32402850,
year = {2020},
author = {Tiwari, M and Panwar, S and Kothidar, A and Tiwari, V},
title = {Rational targeting of Wzb phosphatase and Wzc kinase interaction inhibits extracellular polysaccharides synthesis and biofilm formation in Acinetobacter baumannii.},
journal = {Carbohydrate research},
volume = {492},
number = {},
pages = {108025},
doi = {10.1016/j.carres.2020.108025},
pmid = {32402850},
issn = {1873-426X},
abstract = {Acinetobacter baumannii is an opportunistic nosocomial pathogen, and responsible for high mortality and morbidity. Biofilm formation is one of the resistance determinants, where extracellular polysaccharide (EPS) is an essential component. EPS synthesis and its export is regulated by the bacterial Wza-Wzb-Wzc system. Wzc exhibits auto-phosphorylation protein tyrosine kinase activity, while Wzb is a protein tyrosine phosphatase. Wzb mediates dephosphorylation of Wzc. Dephosphorylated Wzc is required for the export of the EPS through porin Wza-Wzc complex. It shows that the interaction of Wzb with Wzc is critical for the export of EPS. Therefore, if the Wzb-Wzc interaction is inhibited, then it might hinder the EPS transport and diminish the biofilm formation. In this study, we have modelled the Wzb, and Wzc proteins and further validated using PSVS, ProSA, RAMPAGE, and PDBsum. The modelled proteins were used for protein-protein docking. The docked protein-protein complex was minimized by Schrodinger software using OPLS_2005 force field. The binding site of the minimized Wzb-Wzc complex was identified by Sitemap. The high throughput virtual screening identified Labetalol hydrochloride and 4-{1-hydroxy-2-[(1-methyl-3-phenylpropyl) amino] propyl}
phenol from FDA-approved drug library based on their interaction at the interface of Wzb-Wzc complex. The inhibitor-protein complex was further undergone molecular mechanics analysis using Generalized Born model and Solvent Accessibility (MMGBSA) to estimate the binding free energies. The lead was also used to generate the pharmacophore model and screening the molecule with antimicrobial scaffold. The identified lead was experimentally validated for its effect on EPS quantity and biofilm formation by A. baumannii. Wzb-Wzc interaction is essential for biofilm and EPS export; hence, the identified lead might be useful to regulate the biofilm formation by A. baumannii.},
}
@article {pmid32399218,
year = {2020},
author = {Ramazanpour Esfahani, A and Batelaan, O and Hutson, JL and Fallowfield, HJ},
title = {Role of biofilm on virus inactivation in limestone aquifers: implications for managed aquifer recharge.},
journal = {Journal of environmental health science &amp; engineering},
volume = {18},
number = {1},
pages = {21-34},
pmid = {32399218},
issn = {2052-336X},
abstract = {Background: Virus, as nano-sized microorganisms are prevalent in aquifers, which threaten groundwater quality and human health wellbeing. Virus inactivation by attachment onto the limestone surfaces is a determining factor in the transport and retention behavior of virus in carbonaceous aquifers.<br><br>Methods: In the present study, the inactivation of MS2 -as a model virus- by attachment onto the surfaces of limestone grains was investigated in a series of batch experiments under different conditions such as limestone particle size distribution (0.25-0.50, 0.5-1 and 1-2 mm), treated wastewater and RO water, temperature (4 and 22 °C), initial MS2 concentrations (103-107 PFU/mL) and static and dynamic conditions. The experimental data of MS2 inactivation was also fitted to a non-linear kinetic model with shoulder and tailing. The characteristics of biofilm on the surfaces of limestone aquifer materials were assessed using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM).<br><br>Results: The inactivation rate of virus decreased with increasing the adsorbent diameter. Furthermore, virus inactivation was greater at room temperature (22 °C) than 4 °C, in both static and dynamic conditions. The inactivation of virus via attachment onto the limestone aquifer materials in dynamic conditions was higher than under static conditions. In addition, fitting the experimental data with a kinetic model showed that virus inactivation was high at higher temperature, smaller limestone grains and dynamic conditions. Moreover, the experiments with treated wastewater showed that in authentic aqueous media, the virus inactivation was considerably higher than in RO water, due to the presence of either monovalent or divalent cations and surface roughness created by biofilms.<br><br>Conclusion: Finally, in terms of managed aquifer recharge systems, the presence of biofilm increases bacteria and virus retention onto the aquifer surfaces. Graphical abstract.},
}
@article {pmid32397430,
year = {2020},
author = {Castillo Pedraza, MC and de Oliveira Fratucelli, ED and Ribeiro, SM and Florez Salamanca, EJ and da Silva Colin, J and Klein, MI},
title = {Modulation of Lipoteichoic Acids and Exopolysaccharides Prevents Streptococcus mutans Biofilm Accumulation.},
journal = {Molecules (Basel, Switzerland)},
volume = {25},
number = {9},
pages = {},
pmid = {32397430},
issn = {1420-3049},
support = {FAPESP #2014/05423-0, #2017/00753-0, #2017/07408-6, #2017/26623-5//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; #311707/2016-5, #PIBIC41910//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; #405, #443//PROPe-UNESP/ ; },
abstract = {Dental caries is a diet-biofilm-dependent disease. Streptococcus mutans contributes to cariogenic biofilms by producing an extracellular matrix rich in exopolysaccharides and acids. The study aimed to determine the effect of topical treatments with compound 1771 (modulates lipoteichoic acid (LTA) metabolism) and myricetin (affects the synthesis of exopolysaccharides) on S. mutans biofilms. In vitro S. mutans UA159 biofilms were grown on saliva-coated hydroxyapatite discs, alternating 0.1% sucrose and 0.5% sucrose plus 1% starch. Twice-daily topical treatments were performed with both agents alone and combined with and without fluoride: compound 1771 (2.6 µg/mL), myricetin (500 µg/mL), 1771 + myricetin, fluoride (250 ppm), 1771 + fluoride, myricetin + fluoride, 1771 + myricetin + fluoride, and vehicle. Biofilms were evaluated via microbiological, biochemical, imaging, and gene expression methods. Compound 1771 alone yielded less viable counts, biomass, exopolysaccharides, and extracellular LTA. Moreover, the combination 1771 + myricetin + fluoride decreased three logs of bacterium counts, 60% biomass, >74% exopolysaccharides, and 20% LTA. The effect of treatments on extracellular DNA was not pronounced. The combination strategy affected the size of microcolonies and exopolysaccharides distribution and inhibited the expression of genes linked to insoluble exopolysaccharides synthesis. Therefore, compound 1771 prevented the accumulation of S. mutans biofilm; however, the effect was more pronounced when it was associated with fluoride and myricetin.},
}
@article {pmid32397205,
year = {2020},
author = {Vollaro, A and Esposito, A and Esposito, EP and Zarrilli, R and Guaragna, A and De Gregorio, E},
title = {PYED-1 Inhibits Biofilm Formation and Disrupts the Preformed Biofilm of Staphylococcus aureus.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {9},
number = {5},
pages = {},
pmid = {32397205},
issn = {2079-6382},
support = {PRIN2017 (Grant 2017SFBFER to RZ)//Ministero dell'Istruzione, dell'Università e della Ricerca/International ; },
abstract = {Pregnadiene-11-hydroxy-16α,17α-epoxy-3,20-dione-1 (PYED-1), a heterocyclic corticosteroid derivative of deflazacort, exhibits broad-spectrum antibacterial activity against Gram-negative and Gram-positive bacteria. Here, we investigated the effect of PYED-1 on the biofilms of Staphylococcus aureus, an etiological agent of biofilm-based chronic infections such as osteomyelitis, indwelling medical device infections, periodontitis, chronic wound infections, and endocarditis. PYED-1 caused a strong reduction in biofilm formation in a concentration dependent manner. Furthermore, it was also able to completely remove the preformed biofilm. Transcriptional analysis performed on the established biofilm revealed that PYED-1 downregulates the expression of genes related to quorum sensing (agrA, RNAIII, hld, psm, and sarA), surface proteins (clfB and fnbB), secreted toxins (hla, hlb, and lukD), and capsular polysaccharides (capC). The expression of genes that encode two main global regulators, sigB and saeR, was also significantly inhibited after treatment with PYED-1. In conclusion, PYED-1 not only effectively inhibited biofilm formation, but also eradicated preformed biofilms of S. aureus, modulating the expression of genes related to quorum sensing, surface and secreted proteins, and capsular polysaccharides. These results indicated that PYED-1 may have great potential as an effective antibiofilm agent to prevent S. aureus biofilm-associated infections.},
}
@article {pmid32396007,
year = {2020},
author = {Zhang, L and Chichlowski, M and Gross, G and Holle, MJ and Lbarra-Sánchez, LA and Wang, S and Miller, MJ},
title = {Milk Fat Globule Membrane Protects Lactobacillus rhamnosus GG from Bile Stress by Regulating Exopolysaccharide Production and Biofilm Formation.},
journal = {Journal of agricultural and food chemistry},
volume = {68},
number = {24},
pages = {6646-6655},
doi = {10.1021/acs.jafc.0c02267},
pmid = {32396007},
issn = {1520-5118},
abstract = {The milk fat globule membrane (MFGM) is a complex, highly conserved structure surrounding fat droplets secreted into mammalian milk. This study evaluated the impact of MFGM on Lactobacillus rhamnosus GG (LGG). MFGM-10 (2.5 g/L, 5 g/L, and 10 g/L) did not affect LGG growth in MRS medium but enhanced the ability of LGG to survive in the presence of 0.5% porcine bile. In the presence of MFGM-10 (5 g/L) and bile (0.5%), there were less complex polysaccharides in the media and less capsular polysaccharides associated with the LGG cells compared to the bile exposure alone (p < 0.05). The expression of four EPS genes was modulated by bile stress and MFGM. Biofilm thickness was increased (p < 0.05) during bile stress with MFGM compared to other treatments. Furthermore, MFGM increased LGG survival during transit in the murine GI tract. Future experiments will determine the impact of MFGM on LGG probiotic functionality.},
}
@article {pmid32394240,
year = {2020},
author = {Abu El-Wafa, WM and Ahmed, RH and Ramadan, MA},
title = {Synergistic effects of pomegranate and rosemary extracts in combination with antibiotics against antibiotic resistance and biofilm formation of Pseudomonas aeruginosa.},
journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]},
volume = {},
number = {},
pages = {},
doi = {10.1007/s42770-020-00284-3},
pmid = {32394240},
issn = {1678-4405},
abstract = {The combination of plant extract and antibiotic represents a template for developing of antibiofilm drugs. This study investigated the synergistic effects of pomegranate/rosemary/antibiotic combinations against antibiotic resistance and biofilm formation of Pseudomonas aeruginosa. The results showed that 17 (85%) of total P. aeruginosa isolates were biofilm producers; however, 5 (25%) isolates were demonstrated as a strong biofilm producer. The highest MIC level (1024 μg/ml) of tested antibiotics against strong biofilm producer isolates was observed with piperacillin, however the MIC ranges of ceftazidime, gentamycin, imipenem, and levofloxacin against these isolates were reached to (256-1024 μg/ml), (32-1024 μg/ml), (8-1024 μg/ml), and (8-512 μg/ml), respectively. PS-1 was the representative isolate for strong biofilm formation and high antibiotic resistance. 16S rRNA gene analysis suggested that PS-1 (accession No. MN619678) was identified as a strain of P. aeruginosa POA1. Pomegranate and rosemary extracts were the most effective extracts in biofilm inhibition, which significantly inhibited 91.93 and 90.83% of PS-1 biofilm, respectively. Notably, the synergism between both plant extracts and antibiotics has significantly reduced the MICs of used antibiotics at the level lower than the susceptibility breakpoints. Pomegranate/rosemary/antibiotic combinations achieved the highest biofilm eradication, which ranging from 90.0 to 99.6%, followed by the eradication ranges of pomegranate/rosemary combination, rosemary, and pomegranate extracts, which reached to (76.5-85.4%), (53.1-73.7%), and (41.2-71.5%), respectively. The findings suggest that pomegranate/rosemary/antibiotic combinations may be an effective therapeutic agent for antibiotic resistance and biofilm formation of P. aeruginosa.},
}
@article {pmid32394095,
year = {2020},
author = {Tsukatani, T and Sakata, F and Kuroda, R and Akao, T},
title = {Biofilm Eradication Activity of Herb and Spice Extracts Alone and in Combination Against Oral and Food-Borne Pathogenic Bacteria.},
journal = {Current microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00284-020-02017-z},
pmid = {32394095},
issn = {1432-0991},
support = {224//Yamazaki Spice Promotion Foundation/ ; },
abstract = {The purpose of this study was to select herbs and spices with potent biofilm eradication activities. Further, the combined effects of herb and spice extracts against pathogenic biofilms were evaluated. The biofilm eradication activities of ethanol extracts of 104 herbs and spices were measured by combining a colorimetric microbial viability assay with a biofilm formation technique. Ethanol extract of clove had potent biofilm eradication activities against Escherichia coli, Porphyromonas gingivalis, and Streptococcus mutans. Ethanol extracts of eucalyptus and rosemary had potent biofilm eradication activities against P. gingivalis, Staphylococcus aureus and S. mutans. The combination of extracts of clove with eucalyptus or rosemary showed synergistic or additive effects, or both, on biofilm eradication activities. The main biofilm inhibitors in the ethanol extracts of clove, eucalyptus and rosemary were eugenol, macrocarpals and carnosic acid, respectively. The combinations of extracts of clove with eucalyptus or rosemary had potent biofilm eradication activities against oral and food-borne pathogenic bacteria. The findings of the present study reveal that specific combinations of herb and spice extracts may prevent and control biofilm-related oral diseases, food spoilage, and food poisoning.},
}
@article {pmid32393519,
year = {2020},
author = {Kimura, T and Kobayashi, K},
title = {Role of Glutamate Synthase in Biofilm Formation by Bacillus subtilis.},
journal = {Journal of bacteriology},
volume = {202},
number = {14},
pages = {},
doi = {10.1128/JB.00120-20},
pmid = {32393519},
issn = {1098-5530},
abstract = {Bacillus subtilis forms robust biofilms in the presence of large amounts of carbon sources, such as glycerol. However, little is known about the importance of the metabolic systems, or the relationship between metabolic systems and regulatory systems, involved in biofilm formation. Glutamate synthase, encoded by gltAB, is an enzyme that converts 2-ketoglutarate (a tricarboxylic acid [TCA] cycle intermediate) and glutamine into glutamate, which is a general amino group donor in metabolism. Here, we show that a ΔgltA mutant exhibited early arrest of biofilm formation in complex medium containing glycerol. This phenotype was not due to glutamate auxotrophy. Consistent with its biofilm formation phenotype, the ΔgltA mutant exhibited an early decrease in expression of the epsA and tapA operons, which are responsible for production of biofilm matrix polymers. This resulted from decreased activity of their regulator, Spo0A, as evidenced by reduced expression of other Spo0A-regulated genes in the ΔgltA mutant. The ΔgltA mutation prevented biofilm formation only in the presence of large amounts of glycerol. Moreover, limited expression of citrate synthase (but not other TCA enzymes) restored biofilm-forming ability to the ΔgltA mutant. These results indicate that the ΔgltA mutant accumulates an inhibitory intermediate (citrate) in the TCA cycle in the presence of large amounts of glycerol. The ΔgltA mutant formed biofilms when excess iron was added to the medium. Taken together, the data suggest that accumulation of citrate ions by the ΔgltA mutant causes iron shortage due to chelation, which prevents activation of Spo0A and causes defective biofilm formation.IMPORTANCEBacillus subtilis, a model organism for bacterial biofilm formation, forms robust biofilms in a medium-dependent manner. Although the regulatory network that controls biofilm formation has been well studied, the importance of the underlying metabolic systems remains to be elucidated. The present study demonstrates that a metabolic disorder in a well-conserved metabolic system causes accumulation of an inhibitory metabolic intermediate that prevents activation of the system that regulates biofilm formation. These findings increase our understanding of the coordination between cellular metabolic status and the regulatory networks governing biofilm formation.},
}
@article {pmid32392736,
year = {2020},
author = {Brück, HL and Coutte, F and Dhulster, P and Gofflot, S and Jacques, P and Delvigne, F},
title = {Growth Dynamics of Bacterial Populations in a Two-Compartment Biofilm Bioreactor Designed for Continuous Surfactin Biosynthesis.},
journal = {Microorganisms},
volume = {8},
number = {5},
pages = {},
pmid = {32392736},
issn = {2076-2607},
abstract = {Biofilm bioreactors are promising systems for continuous biosurfactant production since they provide process stability through cell immobilization and avoid foam formation. In this work, a two-compartment biofilm bioreactor was designed consisting of a stirred tank reactor and a trickle-bed reactor containing a structured metal packing for biofilm formation. A strong and poor biofilm forming B. subtilis 168 strain due to restored exopolysaccharides (EPS) production or not were cultivated in the system to study the growth behavior of the planktonic and biofilm population for the establishment of a growth model. A high dilution rate was used in order to promote biofilm formation on the packing and wash out unwanted planktonic cells. Biofilm development kinetics on the packing were assessed through a total organic carbon mass balance. The EPS+ strain showed a significantly improved performance in terms of adhesion capacity and surfactin production. The mean surfactin productivity of the EPS+ strain was about 37% higher during the continuous cultivation compared to the EPS- strain. The substrate consumption together with the planktonic cell and biofilm development were properly predicted by the model (α = 0.05). The results show the efficiency of the biofilm bioreactor for continuous surfactin production using an EPS producing strain.},
}
@article {pmid32392720,
year = {2020},
author = {Tse, MCC and Cheung, GSP},
title = {Spatial Cleaning Action of Ultrasonic Irrigation on Enterococcus faecalis Biofilm.},
journal = {Dentistry journal},
volume = {8},
number = {2},
pages = {},
doi = {10.3390/dj8020042},
pmid = {32392720},
issn = {2304-6767},
abstract = {This study aimed to examine the spatial cleaning effect of ultrasonic irrigation in simulated root canal with oblong cross section in the absence of antimicrobial agent. A 7-day E. faecalis biofilm was cultivated in a rectangular, simulated canal model and subjected to passive ultrasonic irrigation (PUI) with sterile saline for 5 minutes. After that, the biofilm was examined by confocal microscopy after bacterial viability staining at 58 sites around and beyond the endosonic file. Results showed that, at the vicinity of the file, the amount of viable bacteria ranged from 13.1% (2.75 mm from the tip) to 40.5% (4.5 mm level). Lesser amounts of live bacteria were observed within 1 mm from the vibrating file, which amount increased for sites farther away. At 3 mm distance, the amount of bacteria (35.5 to 64.4%) was significantly greater than areas situated close to the vibrating file (P < 0.01). Sites next to the anti-nodes of file had less bacteria remaining than sites near the nodes (P = 0.050). Apically (0.5 mm or more), the amount of bacteria was significantly greater than that at the file tip (16.4%) (P < 0.05). It was concluded that PUI is able to dislodge a single-species biofilm, provided that they are situated in close vicinity to the vibrating file.},
}
@article {pmid32392236,
year = {2020},
author = {Kriem, LS and Wright, K and Ccahuana-Vasquez, RA and Rupp, S},
title = {Confocal Raman microscopy to identify bacteria in oral subgingival biofilm models.},
journal = {PloS one},
volume = {15},
number = {5},
pages = {e0232912},
pmid = {32392236},
issn = {1932-6203},
abstract = {The study of oral disease progression, in relation to the accumulation of subgingival biofilm in gingivitis and periodontitis is limited, due to either the ability to monitor plaque in vitro. When compared, optical spectroscopic techniques offer advantages over traditional destructive or biofilm staining approaches, making it a suitable alternative for the analysis and continued development of three-dimensional structures. In this work, we have developed a confocal Raman spectroscopy analysis approach towards in vitro subgingival plaque models. The main objective of this study was to develop a method for differentiating multiple oral subgingival bacterial species in planktonic and biofilm conditions, using confocal Raman microscopy. Five common subgingival bacteria (Fusobacterium nucleatum, Streptococcus mutans, Veillonella dispar, Actinomyces naeslundii and Prevotella nigrescens) were used and differentiated using a 2-way orthogonal Partial Least Square with Discriminant Analysis (O2PLS-DA) for the collected spectral data. In addition to planktonic growth, mono-species biofilms cultured using the 'Zürich Model' were also analyzed. The developed method was successfully used to predict planktonic and mono-species biofilm species in a cross validation setup. The results show differences in the presence and absence of chemical bands within the Raman spectra. The O2PLS-DA model was able to successfully predict 100% of all tested planktonic samples and 90% of all mono-species biofilm samples. Using this approach we have shown that Confocal Raman microscopy can analyse and predict the identity of planktonic and mono-species biofilm species, thus enabling its potential as a technique to map oral multi-species biofilm models.},
}
@article {pmid32392155,
year = {2020},
author = {Naradasu, D and Guionet, A and Miran, W and Okamoto, A},
title = {Microbial current production from Streptococcus mutans correlates with biofilm metabolic activity.},
journal = {Biosensors &amp; bioelectronics},
volume = {162},
number = {},
pages = {112236},
doi = {10.1016/j.bios.2020.112236},
pmid = {32392155},
issn = {1873-4235},
abstract = {Once pathogens form a biofilm, they become more tolerant to drugs and quicker to recover from physical removal than planktonic cells. Because such robustness of a biofilm is associated with the active metabolism of its constituent microbes, establishment of a direct assay quantifying biofilm's metabolic activity is important for developing antibiofilm substrates and techniques. Current production capability via extracellular electron transport (EET) was recently found in Gram-positive pathogens, which we hypothesized to correlate with the metabolic activity of their biofilm. Here, we identified current production from the biofilm of oral pathogen Streptococcus mutans that enables the electrochemical assessments of their metabolic activity in situ which conventionally require gene insertion for a fluorescent protein expression. Single-potential amperometry (SA) showed that S. mutans produced an anodic current and formed a biofilm within 8 h on a +0.4 V electrode vs a standard hydrogen electrode (SHE) in the presence of the electron donor glucose. Current production was significantly decreased by the addition of a metabolic inhibitor Triclosan. Furthermore, the anabolic activity of a single cell using high-resolution mass spectroscopy revealed that higher current production resulted in a higher metabolic fixation of an atomically labeled nitrogen 15N. These results demonstrate that current production in S. mutans reflects its metabolic activity. Given electrochemical impedance spectroscopy (EIS) helps quantifying the bacterial cell adhesion on the electrode, combination of EIS and SA could be a novel assay for EET capable pathogens for quantifying their time-dependent metabolic activity, cellular electrode coverage and physiological response to antibiofilm compounds.},
}
@article {pmid32391052,
year = {2020},
author = {Yadav, MK and Go, YY and Chae, SW and Park, MK and Song, JJ},
title = {Asian Sand Dust Particles Increased Pneumococcal Biofilm Formation in vitro and Colonization in Human Middle Ear Epithelial Cells and Rat Middle Ear Mucosa.},
journal = {Frontiers in genetics},
volume = {11},
number = {},
pages = {323},
pmid = {32391052},
issn = {1664-8021},
abstract = {Introduction: Air pollutants such as Asian sand dust (ASD) and Streptococcus pneumoniae are risk factors for otitis media (OM). In this study, we evaluate the role of ASD in pneumococcal in vitro biofilm growth and colonization on human middle ear epithelium cells (HMEECs) and rat middle ear using the rat OM model.<br><br>Methods: S. pneumoniae D39 in vitro biofilm growth in the presence of ASD (50-300 μg/ml) was evaluated in metal ion-free BHI medium using CV-microplate assay, colony-forming unit (cfu) counts, resazurin staining, scanning electron microscopy (SEM), and confocal microscopy (CF). Biofilm gene expression analysis was performed using real-time RT-PCR. The effects of ASD or S. pneumoniae individually or on co-treatment on HMEECs were evaluated by detecting HMEEC viability, apoptosis, and reactive oxygen species (ROS) production. In vivo colonization of S. pneumoniae in the presence of ASD was evaluated using the rat OM model, and RNA-Seq was used to evaluate the alterations in gene expression in rat middle ear mucosa.<br><br>Results: S. pneumoniae biofilm growth was significantly (P < 0.05) elevated in the presence of ASD. SEM and CF analysis revealed thick and organized pneumococcal biofilms in the presence of ASD (300 μg/ml). However, in the absence of ASD, bacteria were unable to form organized biofilms, the cell size was smaller than normal, and long chain-like structures were formed. Biofilms grown in the presence of ASD showed elevated expression levels of genes involved in biofilm formation (luxS), competence (comA, comB, ciaR), and toxin production (lytA and ply). Prior exposure of HMEECs to ASD, followed by treatment for pneumococci, significantly (P < 0.05) decreased cell viability and increased apoptosis, and ROS production. In vivo experiment results showed significantly (P < 0.05) more than 65% increased bacteria colonization in rat middle ear mucosa in the presence of ASD. The apoptosis, cell death, DNA repair, inflammation and immune response were differentially regulated in three treatments; however, number of genes expressed in co-treatments was higher than single treatment. In co-treatment, antimicrobial protein/peptide-related genes (S100A family, Np4, DEFB family, and RATNP-3B) and OM-related genes (CYLD, SMAD, FBXO11, and CD14) were down regulated, and inflammatory cytokines and interleukins, such as IL1β, and TNF-related gene expression were elevated.<br><br>Conclusion: ASD presence increased the generation of pneumococcal biofilms and colonization.},
}
@article {pmid32390423,
year = {2020},
author = {Tan, CH and Oh, HS and Sheraton, VM and Mancini, E and Joachim Loo, SC and Kjelleberg, S and Sloot, PMA and Rice, SA},
title = {Convection and the Extracellular Matrix Dictate Inter- and Intra-Biofilm Quorum Sensing Communication in Environmental Systems.},
journal = {Environmental science &amp; technology},
volume = {54},
number = {11},
pages = {6730-6740},
doi = {10.1021/acs.est.0c00716},
pmid = {32390423},
issn = {1520-5851},
abstract = {The mechanisms and impact of bacterial quorum sensing (QS) for the coordination of population-level behaviors are well studied under laboratory conditions. However, it is unclear how, in otherwise open environmental systems, QS signals accumulate to sufficient concentration to induce QS phenotypes, especially when quorum quenching (QQ) organisms are also present. We explore the impact of QQ activity on QS signaling in spatially organized biofilms in scenarios that mimic open systems of natural and engineered environments. Using a functionally differentiated biofilm system, we show that the extracellular matrix, local flow, and QQ interact to modulate communication. In still aqueous environments, convection facilitates signal dispersal while the matrix absorbs and relays signals to the cells. This process facilitates inter-biofilm communication even at low extracellular signal concentrations. Within the biofilm, the matrix further regulates the transport of the competing QS and QQ molecules, leading to heterogenous QS behavior. Importantly, only extracellular QQ enzymes can effectively control QS signaling, suggesting that the intracellular QQ enzymes may not have evolved to degrade environmental QS signals for competition.},
}
@article {pmid32390104,
year = {2020},
author = {Abdelfattah, A and Hossain, MI and Cheng, L},
title = {High-strength wastewater treatment using microbial biofilm reactor: a critical review.},
journal = {World journal of microbiology &amp; biotechnology},
volume = {36},
number = {5},
pages = {75},
doi = {10.1007/s11274-020-02853-y},
pmid = {32390104},
issn = {1573-0972},
abstract = {Biofilm reactors retain microbial cells in the form of biofilm which is attached to free moving or fixed carrying materials, thus providing a high active biomass concentration and automatic liquid and solid separation. Nowadays, microbial biofilm reactors have been widely used in high-strength wastewater treatment where very high pollutant removal efficiency is required, which usually requires excessive space and aeration energy for conventional activated sludge-based treatment. This paper provides an overview of microbial biofilm reactors developed over the last half-century, including moving bed biofilm reactor (MBBR), trickling filter (TF) reactor, rotating biological contactor (RBC), membrane biofilm reactor (MBfR), passive aeration simultaneous nitrification and denitrification (PASND) biofilm reactor, for their applications in high-strength wastewater treatment of not only removing carbon, nitrogen, sulphur but also a variety of oxidized contaminants including perchlorate and bromate. Despite the advance of biofilm reactor that exhibits high resistance to excessive pollutants loading, its drawbacks both from engineering and microbiological point of view are reviewed. The future prospects of biofilm reactor are also discussed in this review paper.},
}
@article {pmid32389829,
year = {2020},
author = {Crecencio, RB and Brisola, MC and Bitner, D and Frigo, A and Rampazzo, L and Borges, KA and Furian, TQ and Salle, CTP and Moraes, HLS and Faria, GA and Da Silva, AS and Stefani, LM},
title = {Antimicrobial susceptibility, biofilm formation and genetic profiles of Escherichia coli isolated from retail chicken meat.},
journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases},
volume = {84},
number = {},
pages = {104355},
doi = {10.1016/j.meegid.2020.104355},
pmid = {32389829},
issn = {1567-7257},
abstract = {Brazil is the number one exporter of chicken meat, and this industry maintains constant microbiological vigilance. The objective of this study was to characterize the pathogenicity, antimicrobial resistance (AMR) and the profile of biofilm production of Escherchia coli strains isolated from raw refrigerated cuts of chicken meat sold in retail markets of the four largest poultry companies in Brazil. We collected 150 samples of chicken meat, in order to isolate E. coli and performed susceptibility tests (to amoxicillin associated with clavulanic acid, ceftiofur, enrofloxacin, gentamicin, and trimethoprim + sulfamethoxazole). In addition, the disc approximation test to detect extended spectrum beta-lactamases enzymes (ESBLs) producers was performed. E. coli ability to form biofilm was checked using polystyrene microplates. We also searched for ESBLs genes (blaCTY-M2, blaSHV-1, blaTEM-1, blaCTX-M2, blaOXA-1, blaPSE-1 and AmpC) and adhesion genes (sfa/foc, afa/draB, iha, hrla, fimC, tsh, papC, mat, cr1, felA, fimH and papG) in ESBL-E. coli producers and in those E. coli classified as strongly biofilm formers, respectively. The overall percentage of E. coli isolation was 58.66%, with brand A having the highest percentage (70%), followed by brands D, B and C (60, 53.3 and 50%, respectively). The highest resistance profile was observed for beta-lactams (39.5%), followed by sulfonamide associated to trimethoprim (36.9%) and polymyxin (33.4%). Of the isolates obtained, 77% were non-susceptible to at least one antimicrobial. Brand A showed the highest overall percentage of resistance with 95.23%, followed by brands C (80%), B (75%) and D (69.44%). Overall, 73.86% of the isolates were non susceptible to at least one antibiotic and 36.3% were multiresistants. A total of 17.04% of E. coli strains were identified as ESBLs producers and 70.44% were able to form biofilms (moderate-to-strong). The blaTEM-1 gene was the most prevalent (73.33%), followed by blaSHV-1 (46.66%) and blaCMY-2 (6%). Of the 31 strongly biofilm-forming strains, 26 (83.87%), 24 (77.41%) and 20 (64.51%) expressed fimC, papG and crl genes, respectively. Taken together, our results show that Brazilian chicken meat can be contaminated with E. coli that are non-susceptible to multiple antibiotics, able to form biofilm and showing a diverse repertoire of adhesins linked to pathogenicity depending on the brand evaluated.},
}
@article {pmid32389294,
year = {2020},
author = {Martins de Andrade, V and Bardají, E and Heras, M and Ramu, VG and Junqueira, JC and Diane Dos Santos, J and Castanho, MARB and Conceição, K},
title = {Antifungal and anti-biofilm activity of designed derivatives from kyotorphin.},
journal = {Fungal biology},
volume = {124},
number = {5},
pages = {316-326},
doi = {10.1016/j.funbio.2019.12.002},
pmid = {32389294},
issn = {1878-6146},
abstract = {Kyotorphin (KTP, l-tyrosyl-l-arginine) is an endogenous analgesic neuropeptide first isolated from bovine brain in 1979. Previous studies have shown that kyotorphins possess anti-inflammatory and antimicrobial activity. Six kyotorphins-KTP-NH2, KTP-NH2-DL, ibuprofen-conjugated KTP (IbKTP), IbKTP-NH2, N-methyl-D-Tyr-L-Arg, and N-methyl-L-Tyr-D-Arg-were designed and synthesized to improve lipophilicity and resistance to enzymatic degradation. This study assessed the antimicrobial and antibiofilm activity of these peptides. The antifungal activity of kyotorphins was determined in representative strains of Candida species, including Candida albicans ATCC 10231, Candida krusei ATCC 6258, and six clinical isolates-Candida dubliniensis 19-S, Candida glabrata 217-S, Candida lusitaniae 14-S, Candida novergensis 51-S, Candida parapsilosis 63, and Candida tropicalis 140-S-obtained from the oral cavity of HIV-positive patients. The peptides were synthesized by standard solution or solid-phase synthesis, purified by RP-HPLC (purity >95 %), and characterized by nuclear magnetic resonance. The results of the broth microdilution assay and scanning electron microscopy showed that IbKTP-NH2 presented significant antifungal activity against Candida strains and antibiofilm activity against the clinical isolates. The absence of toxic activity and survival after infection was assessed after injecting the peptide in larvae of Galleria mellonella as experimental infection model. Furthermore, IbKTP-NH2 had strong antimicrobial activity against multidrug-resistant bacteria and fungi and was not toxic to G. mellonella larvae up to a concentration of 500 mM. These results suggest that IbKTP-NH2, in addition to its known effect on cell membranes, can elicit a cellular immune response and, therefore, is promising for biomedical application.},
}
@article {pmid32388374,
year = {2020},
author = {Zhang, X and Wang, C and Wu, P and Yin, W and Xu, L},
title = {New insights on biological nutrient removal by coupling biofilm-based CANON and denitrifying phosphorus removal (CANDPR) process: Long-term stability assessment and microbial community evolution.},
journal = {The Science of the total environment},
volume = {730},
number = {},
pages = {138952},
doi = {10.1016/j.scitotenv.2020.138952},
pmid = {32388374},
issn = {1879-1026},
mesh = {*Biofilms ; Bioreactors ; Denitrification ; *Microbiota ; Nitrogen ; Nutrients ; Phosphorus ; Sewage ; Waste Disposal, Fluid ; Waste Water ; },
abstract = {It was difficult to obtain a stable and efficient biological nutrient removal for high-strength wastewater treatment, the possibility of exploiting innovative CANDPR process, integrating biofilm-based completely autotrophic nitrogen removal over nitrite (CANON) with denitrifying phosphorus removal (DPR) was evaluated to resolve the difficulty. Results revealed that the excellent NH4+-N, PO43--P and COD removal efficiencies of 96%, 96% and 91%, were achieved respectively under a high nitrogen loading rate (0.79 kg·m-3·d-1) without adding organic matters during 320 days operation. Promoting NOx--N recirculation demonstrated as an efficient strategy for further nutrient depletion, facilitating the enhanced NO3--N removal to 100% with the considerably high P-uptake performance. Batch tests confirmed that denitrifying phosphorus accumulating organisms (DPAOs) using NO3--N as electron acceptors accounting for 68% in total PAOs. Dechloromonas was identified as dominating genus in DPR, while Nitrosomonas (1.31%), Candidatus_Kuenenia (5.53%) and Candidatus_Brocadia (1.77%) contributed to the desirable nitrogen removal, indicating that cooperative consortia of DPAOs, AOB and AnAOB were harvested during long-term operation. The CANDPR process was verified to be energy-saving and treatment-reliable for renovating of existing plants.},
}
@article {pmid32388030,
year = {2020},
author = {Recupido, F and Toscano, G and Tatè, R and Petala, M and Caserta, S and Karapantsios, TD and Guido, S},
title = {The role of flow in bacterial biofilm morphology and wetting properties.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {192},
number = {},
pages = {111047},
doi = {10.1016/j.colsurfb.2020.111047},
pmid = {32388030},
issn = {1873-4367},
abstract = {Biofilms are bacterial communities embedded in an extracellular matrix, able to adhere to surfaces. Different experimental set-ups are widely used for in vitro biofilm cultivation; however, a well-defined comparison among different culture conditions, especially suited to interfacial characterization, is still lacking in the literature. The main objective of this work is to study the role of flow on biofilm formation, morphology and interfacial properties. Three different in vitro setups, corresponding to stagnant, shaking, and laminar flow conditions (custom-made flow cell), are used in this work to grow single strain biofilms of Pseudomonas fluorescens AR 11 on glass coupons. Results show that flow conditions significantly influenced biofilm formation kinetics, affecting mass transfer and cell attachment/detachment processes. Distinct morphological patterns are found under different flow regimes. Static contact angle data do not depend significantly on biofilm growth conditions in the parametric range investigated in this work.},
}
@article {pmid32387904,
year = {2020},
author = {Jiang, L and Wu, A and Fang, D and Zhang, Y and Shen, Q and Xu, X and Ji, F},
title = {Denitrification performance and microbial diversity using starch-polycaprolactone blends as external solid carbon source and biofilm carriers for advanced treatment.},
journal = {Chemosphere},
volume = {255},
number = {},
pages = {126901},
doi = {10.1016/j.chemosphere.2020.126901},
pmid = {32387904},
issn = {1879-1298},
mesh = {Biofilms ; Bioreactors/microbiology ; Carbon/chemistry ; Comamonadaceae ; Denitrification ; Nitrates/chemistry ; Nitrogen/chemistry ; Polyesters/*chemistry ; Starch/chemistry ; Temperature ; Waste Disposal, Fluid/*methods ; Waste Water/chemistry ; },
abstract = {Enhanced nitrate removal from the secondary effluent in municipal wastewater treatment plants (WWTPs) is essential for avoiding water eutrophication. To this end, a vertical baffled solid-phase denitrification reactor (VBSDR) was developed using a starch and polycaprolactone (PCL) blend plate (S-PCL) as a carbon source and biofilm carrier. In this study, we evaluated the denitrification performance and microbial diversity of the VBSDR. The results of the Fourier transform infrared spectroscopy (FTIR), carbon leaching experiment, and scanning electron microscopy (SEM) demonstrated that the S-PCL structure can be attached and degraded more rapidly. Furthermore, the denitrification performance under varied operational conditions, i.e., influent nitrate loading rate (NLR) and operating temperature, was also investigated. Herein, when treating low C/N ratio and low-strength wastewater, a high denitrification rate (DR) [0.33 gN/(L·d)] was achieved. The effect of temperature on DR can be described by the Arrhenius-type equation, which shows that low temperature has a negative influence on DR and nitrate removal efficiency. Furthermore, DR was simultaneously affected by the NLR and temperature. The microbial diversity and community structure were determined by Illumina high-throughput sequencing. The special carbon source led to Acidovorax (denitrifying bacteria) and Flavobacterium (hydrolysis acidifying bacteria) being the VBSDR biofilm's most predominant functional bacteria at the genus level.},
}
@article {pmid32387459,
year = {2020},
author = {Bohm, GC and Gándara, L and Di Venosa, G and Mamone, L and Buzzola, F and Casas, A},
title = {Photodynamic inactivation mediated by 5-aminolevulinic acid of bacteria in planktonic and biofilm forms.},
journal = {Biochemical pharmacology},
volume = {177},
number = {},
pages = {114016},
doi = {10.1016/j.bcp.2020.114016},
pmid = {32387459},
issn = {1873-2968},
abstract = {Bacterial photodynamic inactivation (PDI) employing endogenous production of porphyrins from 5-aminolevulinic acid (ALA) - named ALA-PDI-, is a new promising tool to achieve bacteria control in non-spread infections. The technique combines the action of the porphyrins acting as photosensitisers with light, to produce reactive oxygen species to target the pathogen. To date, some clinical applications of ALA-PDI have been reported although variable responses ranging from total eradication to absence of photokilling were found. ALA-PDI conducted at suboptimal conditions may lead to misleading results and the complexity of haem synthesis in bacteria hinders the optimization of the treatment. The present work aimed to gain insight on the variables affecting ALA-PDI in Gram-positives and Gram-negatives bacteria growing on planktonic and biofilm cultures and to correlate the degree of the response with the amount and type of porphyrin synthesised. Staphylococcus epidermidis and Escherichia coli clinical isolates and Pseudomonas aeruginosa ATCC27853 and Staphylococcus aureus ATCC25923 strains were utilised, and the optimal conditions of concentration and time exposure of ALA, and light dose were set. In both Gram-positive species analysed, a peak of porphyrin synthesis was observed at 1-2 mM ALA in biofilm and planktonic cultures, which fairly correlated with the decrease in the number of CFU after PDI (5 to 7 logs) and porphyrin content was in the same order of magnitude. In addition, ALA-PDI was similarly effective for planktonic and biofilm S. aureus cultures, and more effective in S. epidermidis planktonic cultures at low light doses. Beyond a certain light dose, it was not possible to achieve further photosensitization. Similarly, a plateau of cell death was attained at a certain ALA incubation time. Accumulation of hydrophilic porphyrins at longer incubation periods was observed. The proportion of porphyrins changed as a function of ALA concentration and incubation time in the Gram-positive bacteria, though we did not find a clear correlation between the porphyrin type and PDI response. As a salient feature was the presence of isococroporphyrin isoforms in both Gram-positive and Gram-negative bacteria. Gram-negative bacteria were quite refractory to the treatment: P. aeruginosa was slightly inactivated (4-logs reduction) at 40 mM ALA, whereas E. coli was not inactivated at all. These species accumulated high ALA quantities and the amount of porphyrins did not correlate with the degree of photoinactivation. Our microscopy studies show that porphyrins are not located in the envelopes of Gram-negative bacteria, reinforcing the hypothesis that endogenous porphyrins fail to attack these structures.},
}
@article {pmid32384621,
year = {2020},
author = {Azzola, F and Ionescu, AC and Ottobelli, M and Cavalli, N and Brambilla, E and Corbella, S and Francetti, L},
title = {Biofilm Formation on Dental Implant Surface Treated by Implantoplasty: An In Situ Study.},
journal = {Dentistry journal},
volume = {8},
number = {2},
pages = {},
doi = {10.3390/dj8020040},
pmid = {32384621},
issn = {2304-6767},
abstract = {Peri-implantitis is a biofilm-related disease whose characteristics are peri-implant tissues inflammation and bone resorption. Some clinical trials report beneficial effects after implantoplasty, namely the surgical smoothening of the implant surface, but there is a lack of data about the development of the bacterial biofilm on those smoothened surfaces. The aim of this study is to evaluate how implantoplasty influences biofilm formation. Three implants with moderately rough surfaces (control) and three implants treated with implantoplasty (test) were set on a tray reproducing the supra- and sub-gingival environment. One volunteer wore this tray for five days. Every 24 h, plaque coverage was measured and, at the end of the period of observartion, the implant surfaces were analyzed using scanning electron microscopy and confocal laser scanning microscopy. The proportion of implant surface covered with plaque was 65% (SD = 7.07) of the control implants and 16% (SD = 0) of the test implants. Untreated surfaces showed mature, complex biofilm structures with wide morphological diversity, and treated surfaces did not show the formation of mature biofilm structures. This study supports the efficacy of implantoplasty in reducing plaque adhesion and influencing biofilm formation. These results can be considered a preliminary proof of concept, but they may encourage further studies about the effects of implantoplasty on biofilm formation.},
}
@article {pmid32384241,
year = {2020},
author = {Shi, Y and Tian, Z and Gillings, MR and Zhang, Y and Zhang, H and Huyan, J and Yang, M},
title = {Novel Transposon Tn6433 Variants Accelerate the Dissemination of tet(E) in Aeromonas in an Aerobic Biofilm Reactor under Oxytetracycline Stresses.},
journal = {Environmental science &amp; technology},
volume = {54},
number = {11},
pages = {6781-6791},
doi = {10.1021/acs.est.0c01272},
pmid = {32384241},
issn = {1520-5851},
abstract = {Little is known about the mechanisms that disseminate antibiotic resistance genes (ARGs) in wastewater microbial communities under antibiotic stress. The role of horizontal transfer mechanisms in dissemination of ARGs in an aerobic biofilm reactor under incremental oxytetracycline doses from 0 to 50 mg/L was studied. Aeromonas strains were the most common culturable bacteria in the reactor, with tet(E) as the most prevalent ARGs (73.3%) being possibly responsible for the oxytetracycline resistance phenotype. Genomic sequencing demonstrated that tet(E) was mainly carried by a Tn3 family transposon named Tn6433, whose incidence increased from 14.6% to 75.0% across the treatments. Tn6433 carrying tet(E) was initially detected in Aeromonas chromosomes at an oxytetracycline dose of 1 mg/L but subsequently detected on plasmids pAeca1-a variants (pAeca1-a, pAeca1-b, and pAeme6) and pAeca2 under higher oxytetracycline stress. The core region of the Tn6433-tet(E) structure was highly conserved, consisting of a transposition and resolution module, a class 1 integron, core passenger genes, and a Tn1722/Tn501-like transposon. Such a structure was found on both the chromosome and plasmids, suggesting that Tn6433 mediated the transposition of tet(E) from the chromosome to plasmid pAeca2 under increasing stresses. Bacteria carrying the transferable plasmid pAeca1-a were dominant in high antibiotic treatments, suggesting that Tn6433 disseminated tet(E), conferring selective advantages to recipients of this ARG.},
}
@article {pmid32382563,
year = {2020},
author = {Siddique, MH and Aslam, B and Imran, M and Ashraf, A and Nadeem, H and Hayat, S and Khurshid, M and Afzal, M and Malik, IR and Shahzad, M and Qureshi, U and Khan, ZUH and Muzammil, S},
title = {Effect of Silver Nanoparticles on Biofilm Formation and EPS Production of Multidrug-Resistant Klebsiella pneumoniae.},
journal = {BioMed research international},
volume = {2020},
number = {},
pages = {6398165},
pmid = {32382563},
issn = {2314-6141},
abstract = {Antibiotic resistance against present antibiotics is rising at an alarming rate with need for discovery of advanced methods to treat infections caused by resistant pathogens. Silver nanoparticles are known to exhibit satisfactory antibacterial and antibiofilm activity against different pathogens. In the present study, the AgNPs were synthesized chemically and characterized by UV-Visible spectroscopy, scanning electron microscopy, and X-ray diffraction. Antibacterial activity against MDR K. pneumoniae strains was evaluated by agar diffusion and broth microdilution assay. Cellular protein leakage was determined by the Bradford assay. The effect of AgNPs on production on extracellular polymeric substances was evaluated. Biofilm formation was assessed by tube method qualitatively and quantitatively by the microtiter plate assay. The cytotoxic potential of AgNPs on HeLa cell lines was also determined. AgNPs exhibited an MIC of 62.5 and 125 μg/ml, while their MBC is 250 and 500 μg/ml. The production of extracellular polymeric substance decreased after AgNP treatment while cellular protein leakage increased due to higher rates of cellular membrane disruption by AgNPs. The percentage biofilm inhibition was evaluated to be 64% for K. pneumoniae strain MF953600 and 86% for MF953599 at AgNP concentration of 100 μg/ml. AgNPs were evaluated to be minimally cytotoxic and safe at concentrations of 15-120 μg/ml. The data evaluated by this study provided evidence of AgNPs being safe antibacterial and antibiofilm compounds against MDR K. pneumoniae.},
}
@article {pmid32382020,
year = {2019},
author = {Dubois, T and Tremblay, YDN and Hamiot, A and Martin-Verstraete, I and Deschamps, J and Monot, M and Briandet, R and Dupuy, B},
title = {A microbiota-generated bile salt induces biofilm formation in Clostridium difficile.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {1},
pages = {14},
doi = {10.1038/s41522-019-0087-4},
pmid = {32382020},
issn = {2055-5008},
mesh = {Bile Acids and Salts/*metabolism/pharmacology ; Biofilms/drug effects/*growth &amp; development ; Cholates/metabolism ; Clostridiales/metabolism ; Clostridium difficile/drug effects/genetics/*physiology ; Deoxycholic Acid/pharmacology ; Gene Expression Profiling ; Metabolic Networks and Pathways ; Microbial Interactions ; *Microbiota ; },
abstract = {Clostridium difficile is a major cause of nosocomial infections. Bacterial persistence in the gut is responsible for infection relapse; sporulation and other unidentified mechanisms contribute to this process. Intestinal bile salts cholate and deoxycholate stimulate spore germination, while deoxycholate kills vegetative cells. Here, we report that sub-lethal concentrations of deoxycholate stimulate biofilm formation, which protects C. difficile from antimicrobial compounds. The biofilm matrix is composed of extracellular DNA and proteinaceous factors that promote biofilm stability. Transcriptomic analysis indicates that deoxycholate induces metabolic pathways and cell envelope reorganization, and represses toxin and spore production. In support of the transcriptomic analysis, we show that global metabolic regulators and an uncharacterized lipoprotein contribute to deoxycholate-induced biofilm formation. Finally, Clostridium scindens enhances biofilm formation of C. difficile by converting cholate into deoxycholate. Together, our results suggest that deoxycholate is an intestinal signal that induces C. difficile persistence and may increase the risk of relapse.},
}
@article {pmid32381824,
year = {2020},
author = {Gómez, C and Salcedo-Moncada, D and Ayala, G and Watanabe, R and Pineda, M and Alvítez-Temoche, D and Mayta-Tovalino, F},
title = {Antimicrobial Efficacy of Calcium and Sodium Hypochlorite at Different Concentrations on a Biofilm of Enterococcus faecalis and Candida albicans: An In Vitro Comparative Study.},
journal = {The journal of contemporary dental practice},
volume = {21},
number = {2},
pages = {178-182},
pmid = {32381824},
issn = {1526-3711},
mesh = {*Anti-Infective Agents ; Biofilms ; Calcium ; Candida albicans ; *Enterococcus faecalis ; Root Canal Irrigants ; Sodium Hypochlorite ; },
abstract = {AIM: To compare the antimicrobial efficacy of sodium hypochlorite (NaClO at 2.5% and 5.25%) and calcium hypochlorite [Ca(ClO)2 at 2.5%] on a biofilm of Enterococcus faecalis ATCC 29212™ and Candida albicans ATCC 10231™.<br><br>MATERIALS AND METHODS: We performed an experimental in vitro study. Strains of C. albicans and E. faecalis, which had previously been reactivated were used. Then the colonies to be used were standardized in a turbidity standard to guarantee a quantity of 108 (CFU/mL) using the McFarland scale (0.5). Subsequently, the biofilm formed in brain-heart infusion agar was seeded into 42 sterile disks previously embedded with the experimental substances. Both 2.5% NaClO and Ca(ClO)2 solutions were placed in each Petri dish. They were then incubated at 37°C for 24 hours and the inhibition halos were measured using the Kirby-Bauer technique.<br><br>RESULTS: The means between the halos corresponding to NaClO and Ca(ClO)2 at 2.5% were 13.38 ± 0.64 mm and 13.42 ± 0.62 mm, respectively. According to the Tukey test, no statistically significant differences were found between the hypochlorite groups evaluated (p = 0.989).<br><br>CONCLUSION: Both Ca(ClO)2 and NaClO have a similar antimicrobial efficacy with biofilm based on E. faecalis and C. albicans, with no statistically significant differences between the two.<br><br>CLINICAL SIGNIFICANCE: This study demonstrates the effectiveness of Ca(ClO)2 and NaClO as endodontic irrigators to combat the most frequent microorganisms of the root canal.},
}
@article {pmid32380504,
year = {2020},
author = {Khamari, B and Lama, M and Pachi Pulusu, C and Biswal, APP and Lingamallu, SM and Mukkirla, BS and Sahoo, AKK and Dash, HSNSN and Sharda, R and Kumar, P and Bulagonda, EP},
title = {Molecular analyses of biofilm-producing clinical Acinetobacter baumannii isolates from a South Indian tertiary care hospital.},
journal = {Medical principles and practice : international journal of the Kuwait University, Health Science Centre},
volume = {},
number = {},
pages = {},
doi = {10.1159/000508461},
pmid = {32380504},
issn = {1423-0151},
abstract = {OBJECTIVES: The aim of the study was to determine the presence of antimicrobial resistant (AMR), virulence genes and mobile genetic elements in fourteen biofilm producing clinical isolates of A. baumannii.<br><br>MATERIALS AND METHODS: PCR amplification was performed to analyse the prevalence of genes associated with antibiotic resistance (ESBLs, MBLs), virulence factors, MGEs (class 1 integron, Tn1213, AbaR) and comM among the study isolates. Further, Random Amplified Polymorphic DNA (RAPD) was employed to understand their phylogenetic relationship. All the isolates were investigated for biofilm production.<br><br>RESULTS: Two isolates were antibiotic sensitive (AS); while, three were multi drug resistant (MDR) and the remaining ten were extensively drug resistant (XDR). Majority of the isolates were found to be positive for biofilm production and were sensitive against tetracycline and colistin only. Ab14 and Ab11 were found to be resistant to minocycline and colistin respectively. blaTEM, blaOXA, blaNDM, blaVIM, blaSIM and blaPER-1; class 1 integron; composite transposon Tn1213; AbaR resistance island and virulence factor genes were detected among the isolates. These pathogens were found to have originated from multiple clonal lineages.<br><br>CONCLUSION: Biofilm producing A. baumannii with multiple virulence and AMR genes pose serious clinical challenges. The presence of MGEs further compounds the situation as these isolates serve as potential reservoirs of AMR and virulence genes. Together with their capacity for natural competence, A. baumannii if left unchecked, will lead to spread of resistance determinants to previously sensitive bacteria and may aid in the emergence of untreatable pan drug resistant phenotypes.},
}
@article {pmid32380254,
year = {2020},
author = {Amaral, LS and Ribeiro, AO and Perussi, JR},
title = {Images evidence of Hypericin photoinactivation of E. faecalis: from planktonic culture to mammalian cells selectivity up to biofilm disruption.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {101759},
doi = {10.1016/j.pdpdt.2020.101759},
pmid = {32380254},
issn = {1873-1597},
abstract = {Antimicrobial Photodynamic Therapy (aPDT) is an alternative for microbiological inactivation. The aPDT is a method that uses a photosensitizer (PS) excited by visible light at the appropriate wavelength and the molecular oxygen present in the tissues resulting in the production of reactive oxygen species, which causes oxidative damage to biological molecules. This study aimed to perform an in vitro experimental sequence for photoinactivation of E. faecalis using Hypericin (HY) from planktonic culture to selectivity assays using mammalian cells up to biofilm. The results show that E. faecalis rapidly absorb HY. The levels of inactivation of E. faecalis reached up to 99% in planktonic culture. Transmission and Scanning Electron Microscopy demonstrate the remarkable morphological alterations resulting from photooxidation being the loss of membrane integrity assessed by fluorescence microscopy combined with a LIVE/DEAD™ kit. HY did not present cytotoxicity to the fibroblasts cell at the used conditions proving to be a selective molecule. Finally, 60% of photoinactivation was observed in the biofilm of E. faecalis when subject to HY-aPDT. These outcomes show the advantages of a sequential in vitro experiments besides showing that HY is a potential PS for clinical trials due to its selectivity and photodynamic effect. Besides, this study draws attention to the benefits of using methodologies that can evidence the antimicrobial effect beyond the typical constatation of cell death.},
}
@article {pmid32378822,
year = {2020},
author = {Natan, M and Jacobi, G and Banin, E and Ashkenazi, S},
title = {Prevention and Treatment of Pseudomonas Aeruginosa-Based Biofilm with Ethanol.},
journal = {The Israel Medical Association journal : IMAJ},
volume = {22},
number = {5},
pages = {299-302},
pmid = {32378822},
issn = {1565-1088},
mesh = {Anti-Infective Agents, Local/*administration &amp; dosage/pharmacology ; Biofilms/*drug effects ; Catheter-Related Infections/prevention &amp; control ; Ethanol/*administration &amp; dosage/pharmacology ; Humans ; Microbial Sensitivity Tests ; Pseudomonas Infections/prevention &amp; control ; Pseudomonas aeruginosa/*drug effects/*physiology ; },
abstract = {BACKGROUND: Although indwelling catheters are increasingly used in modern medicine, they can be a source of microbial contamination and hard-to-treat biofilms, which jeopardize patient lives. At times 70% ethanol is used as a catheter-lock solution due to its bactericidal properties. However, high concentrations of ethanol can result in adverse effects and in malfunction of the catheters.<br><br>OBJECTIVES: To determine whether low concentrations of ethanol can prevent and treat biofilms of Pseudomonas aeruginosa.<br><br>METHODS: Ethanol was tested at a concentration range of 0.625-80% against laboratory and clinical isolates of P. aeruginosa for various time periods (2-48 hours). The following parameters were evaluated following ethanol exposure: prevention of biofilm formation, reduction of biofilm metabolic activity, and inhibition of biofilm regrowth.<br><br>RESULTS: Exposing P. aeruginosa to twofold ethanol gradients demonstrated a significant biofilm inhibition at concentrations as low as 2.5%. Treating pre-formed biofilms of P. aeruginosa with 20% ethanol for 4 hours caused a sharp decay in the metabolic activity of both the laboratory and clinical P. aeruginosa isolates. In addition, treating mature biofilms with 20% ethanol prevented the regrowth of bacteria encased within it.<br><br>CONCLUSIONS: Low ethanol concentrations (2.5%) can prevent in vitro biofilm formation of P. aeruginosa. Treatment of previously formed biofilms can be achieved using 20% ethanol, thereby keeping the catheters intact and avoiding complications that can result from high ethanol concentrations.},
}
@article {pmid32377640,
year = {2020},
author = {Xiu, W and Gan, S and Wen, Q and Qiu, Q and Dai, S and Dong, H and Li, Q and Yuwen, L and Weng, L and Teng, Z and Mou, Y and Wang, L},
title = {Biofilm Microenvironment-Responsive Nanotheranostics for Dual-Mode Imaging and Hypoxia-Relief-Enhanced Photodynamic Therapy of Bacterial Infections.},
journal = {Research (Washington, D.C.)},
volume = {2020},
number = {},
pages = {9426453},
pmid = {32377640},
issn = {2639-5274},
abstract = {The formation of bacterial biofilms closely associates with infectious diseases. Until now, precise diagnosis and effective treatment of bacterial biofilm infections are still in great need. Herein, a novel multifunctional theranostic nanoplatform based on MnO2 nanosheets (MnO2 NSs) has been designed to achieve pH-responsive dual-mode imaging and hypoxia-relief-enhanced antimicrobial photodynamic therapy (aPDT) of bacterial biofilm infections. In this study, MnO2 NSs were modified with bovine serum albumin (BSA) and polyethylene glycol (PEG) and then loaded with chlorin e6 (Ce6) as photosensitizer to form MnO2-BSA/PEG-Ce6 nanosheets (MBP-Ce6 NSs). After being delivered into the bacterial biofilm-infected tissues, the MBP-Ce6 NSs could be decomposed in acidic biofilm microenvironment and release Ce6 with Mn2+, which subsequently activate both fluorescence (FL) and magnetic resonance (MR) signals for effective dual-mode FL/MR imaging of bacterial biofilm infections. Meanwhile, MnO2 could catalyze the decomposing of H2O2 in biofilm-infected tissues into O2 and relieve the hypoxic condition of biofilm, which significantly enhances the efficacy of aPDT. An in vitro study showed that MBP-Ce6 NSs could significantly reduce the number of methicillin-resistant Staphylococcus aureus (MRSA) in biofilms after 635 nm laser irradiation. Guided by FL/MR imaging, MRSA biofilm-infected mice can be efficiently treated by MBP-Ce6 NSs-based aPDT. Overall, MBP-Ce6 NSs not only possess biofilm microenvironment-responsive dual-mode FL/MR imaging ability but also have significantly enhanced aPDT efficacy by relieving the hypoxia habitat of biofilm, which provides a promising theranostic nanoplatform for bacterial biofilm infections.},
}
@article {pmid32374766,
year = {2020},
author = {Nikinmaa, S and Alapulli, H and Auvinen, P and Vaara, M and Rantala, J and Kankuri, E and Sorsa, T and Meurman, J and Pätilä, T},
title = {Dual-light photodynamic therapy administered daily provides a sustained antibacterial effect on biofilm and prevents Streptococcus mutans adaptation.},
journal = {PloS one},
volume = {15},
number = {5},
pages = {e0232775},
pmid = {32374766},
issn = {1932-6203},
abstract = {Antibacterial photodynamic therapy (aPDT) and antibacterial blue light (aBL) are emerging treatment methods auxiliary to mechanical debridement for periodontitis. APDT provided with near-infrared (NIR) light in conjunction with an indocyanine green (ICG) photosensitizer has shown efficacy in several dental in-office-treatment protocols. In this study, we tested Streptococcus mutans biofilm sensitivity to either aPDT, aBL or their combination dual-light aPDT (simultaneous aPDT and aBL) exposure. Biofilm was cultured by pipetting diluted Streptococcus mutans suspension with growth medium on the bottom of well plates. Either aPDT (810 nm) or aBL (405 nm) or a dual-light aPDT (simultaneous 810 nm aPDT and 405 nm aBL) was applied with an ICG photosensitizer in cases of aPDT or dual-light, while keeping the total given radiant exposure constant at 100 J/cm2. Single-dose light exposures were given after one-day or four-day biofilm incubations. Also, a model of daily treatment was provided by repeating the same light dose daily on four-day and fourteen-day biofilm incubations. Finally, the antibacterial action of the dual-light aPDT with different energy ratios of 810 nm and 405 nm of light were examined on the single-day and four-day biofilm protocols. At the end of each experiment the bacterial viability was assessed by colony-forming unit method. Separate samples were prepared for confocal 3D biofilm imaging. On a one-day biofilm, the dual-light aPDT was significantly more efficient than aBL or aPDT, although all modalities were bactericidal. On a four-day biofilm, a single exposure of aPDT or dual-light aPDT was more efficient than aBL, resulting in a four logarithmic scale reduction in bacterial counts. Surprisingly, when the same amount of aPDT was repeated daily on a four-day or a fourteen-day biofilm, bacterial viability improved significantly. A similar improvement in bacterial viability was observed after repetitive aBL application. This viability improvement was eliminated when dual-light aPDT was applied. By changing the 405 nm to 810 nm radiant exposure ratio in dual-light aPDT, the increase in aBL improved the antibacterial action when the biofilm was older. In conclusion, when aPDT is administered repeatedly to S. mutans biofilm, a single wavelength-based aBL or aPDT leads to a significant biofilm adaptation and increased S. mutans viability. The combined use of aBL light in synchrony with aPDT arrests the adaptation and provides significantly improved and sustained antibacterial efficacy.},
}
@article {pmid32373581,
year = {2020},
author = {Cho, KH and Tryon, RG and Kim, JH},
title = {Screening for Diguanylate Cyclase (DGC) Inhibitors Mitigating Bacterial Biofilm Formation.},
journal = {Frontiers in chemistry},
volume = {8},
number = {},
pages = {264},
pmid = {32373581},
issn = {2296-2646},
abstract = {The majority of bacteria in the natural environment organize themselves into communal biofilms. Biofilm formation benefits bacteria conferring resistance to harmful molecules (e.g., antibiotics, disinfectants, and host immune factors) and coordinating their gene expression through quorum sensing (QS). A primary signaling molecule promoting bacterial biofilm formation is the universal second messenger cyclic di-GMP. This dinucleotide predominantly controls the gene expression of motility, adhesins, and capsule production to coordinate biofilm formation. Cyclic di-GMP is synthesized by diguanylate cyclases (DGCs) that have a GGDEF domain and is degraded by phosphodiesterases (PDEs) containing either an EAL or an HD-GYP domain. Since high cellular c-di-GMP concentrations are correlated with promoting the ability of bacteria to form biofilms, numerous research endeavors to identify chemicals capable of inhibiting the c-di-GMP synthesis activity of DGCs have been performed in order to inhibit bacterial biofilm formation. This review describes currently identified chemical inhibitors that disturb the activity of DGCs and the methods of screening and assay for their discovery.},
}
@article {pmid32373078,
year = {2020},
author = {Wang, Y and Gong, S and Dong, X and Li, J and Grenier, D and Yi, L},
title = {In vitro Mixed Biofilm of Streptococcus suis and Actinobacillus pleuropneumoniae Impacts Antibiotic Susceptibility and Modulates Virulence Factor Gene Expression.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {507},
pmid = {32373078},
issn = {1664-302X},
abstract = {Streptococcus suis (S. suis) and Actinobacillus pleuropneumoniae (A. pleuropneumoniae) are primary swine pathogens that have been frequently co-isolated from pigs suffering from severe respiratory disease. The purpose of this study was to investigate the biological impacts of the interactions between S. suis and A. pleuropneumoniae. A single- and dual-species culture model was established in vitro via S. suis HA9801 (serotype 2) and A. pleuropneumoniae CVCC265 (serotype 1). The single or mixed biofilms were imaged by confocal laser scanning microscopy. The biomass and viable cells in biofilms were quantified by crystal violet staining and determination of colony-forming units. The antibiotic susceptibility was determined by a microdilution broth method. The differences in gene transcription in pure- or mixed-species biofilms of S. suis and A. pleuropneumoniae was evaluated by quantitative PCR. S. suis and A. pleuropneumoniae formed two-species biofilms when co-cultured in vitro. When co-cultured with S. suis, biofilm formation by A. pleuropneumoniae was significantly increased with the absence of NAD that is necessary for the growth of A. pleuropneumoniae. Moreover, compared with monocultures, the antibiotic resistance of S. suis and A. pleuropneumoniae was both enhanced in the co-culture model. When grown in dual-species biofilms, for A. pleuropneumoniae, genes associated with virulence factors, including exotoxins and adhesins, were significantly upregulated. For S. suis, virulence factor-related genes cps2, gdh, mrp, and sly were highly induced. These results suggest that the interspecies interactions between S. suis and A. pleuropneumoniae may be cooperative under specific conditions and may play an important role in the disease progression and persistent infection.},
}
@article {pmid32372498,
year = {2020},
author = {Wrobel, A and Saragliadis, A and Pérez-Ortega, J and Sittman, C and Göttig, S and Liskiewicz, K and Spence, MH and Schneider, K and Leo, JC and Arenas, J and Linke, D},
title = {The inverse autotransporters of Yersinia ruckeri, YrInv and YrIlm, contribute to biofilm formation and virulence.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.15051},
pmid = {32372498},
issn = {1462-2920},
support = {704903//H2020 Marie Skłodowska-Curie Actions/ ; 249793 and 240483//Norges Forskningsråd/ ; //Universitetet i Oslo Department of Biosciences - COMPI/ ; },
abstract = {Yersinia ruckeri causes enteric redmouth disease (ERM) that mainly affects salmonid fishes and leads to significant economic losses in the aquaculture industry. An increasing number of outbreaks and the lack of effective vaccines against some serotypes necessitates novel measures to control ERM. Importantly, Y. ruckeri survives in the environment for long periods, presumably by forming biofilms. How the pathogen forms biofilms and which molecular factors are involved in this process, remains unclear. Yersinia ruckeri produces two surface-exposed adhesins, belonging to the inverse autotransporters (IATs), called Y. ruckeri invasin (YrInv) and Y. ruckeri invasin-like molecule (YrIlm). Here, we investigated whether YrInv and YrIlm play a role in biofilm formation and virulence. Functional assays revealed that YrInv and YrIlm promote biofilm formation on different abiotic substrates. Confocal microscopy revealed that they are involved in microcolony interaction and formation, respectively. The effect of both IATs on biofilm formation correlated with the presence of different biopolymers in the biofilm matrix, including extracellular DNA, RNA and proteins. Moreover, YrInv and YrIlm contributed to virulence in the Galleria mellonella infection model. Taken together, we propose that both IATs are possible targets for the development of novel diagnostic and preventative strategies to control ERM.},
}
@article {pmid32372396,
year = {2020},
author = {Köder, K and Hardt, S and Gellert, MS and Haupenthal, J and Renz, N and Putzier, M and Perka, C and Trampuz, A},
title = {Outcome of spinal implant-associated infections treated with or without biofilm-active antibiotics: results from a 10-year cohort study.},
journal = {Infection},
volume = {},
number = {},
pages = {},
doi = {10.1007/s15010-020-01435-2},
pmid = {32372396},
issn = {1439-0973},
abstract = {PURPOSE: Biofilm-active antibiotics are suggested to improve the outcome of implant-associated infections; however, their role in infections after spinal instrumentation is unclear. Therefore, we evaluated the outcome of patients with spinal implant-associated infections treated with and without biofilm-active antibiotics.<br><br>METHODS: The probability of infection-free survival was estimated for treatment of spinal implant-associated infections with and without biofilm-active antibiotics using the Kaplan-Meier method; Cox proportional-hazards regression model was used to identify factors associated with treatment failure.<br><br>RESULTS: Among 93 included patients, early-onset infection was diagnosed in 61 (66%) and late-onset in 32 infections (34%). Thirty patients (32%) were treated with biofilm-active antibiotic therapy and 63 (68%) without it. The infection-free survival after a median follow-up of 53.7 months (range, 8 days-9.4 years) was 67% (95% confidence interval [CI], 55-82%) after 1 year and 58% (95% CI 43-71%) after 2 years. The infection-free survival after 1 and 2 years was 94% (95% CI 85-99%) and 84% (95% CI 71-93%) for patients treated with biofilm-active antibiotics, respectively, and 57% (95% CI 39-80%) and 49% (95% CI 28-61%) for those treated without biofilm-active antibiotics, respectively (p = 0.009). Treatment with biofilm-active antibiotics (hazard ratio [HR], 0.23, 95% CI 0.07-0.77), infection with Staphylococcus auras (HR, 2.19, 95% CI 1.04-4.62) and polymicrobial infection (HR, 2.44, 95% CI 1.09-6.04) were significantly associated with treatment outcome. Severe pain was observed more often in patients without biofilm-active antibiotic therapy (49% vs. 18%, p = 0.027).<br><br>CONCLUSION: Treatment with biofilm-active antibiotics was associated with better treatment outcome and less postoperative pain intensity.},
}
@article {pmid32371860,
year = {2020},
author = {Gu, H and Lee, SW and Carnicelli, J and Zhang, T and Ren, D},
title = {Magnetically driven active topography for long-term biofilm control.},
journal = {Nature communications},
volume = {11},
number = {1},
pages = {2211},
pmid = {32371860},
issn = {2041-1723},
support = {R21 AI142424/AI/NIAID NIH HHS/United States ; 1R21AI142424-01//U.S. Department of Health &amp; Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; },
abstract = {Microbial biofilm formation on indwelling medical devices causes persistent infections that cannot be cured with conventional antibiotics. To address this unmet challenge, we engineer tunable active surface topographies with micron-sized pillars that can beat at a programmable frequency and force level in an electromagnetic field. Compared to the flat and static controls, active topographies with the optimized design prevent biofilm formation and remove established biofilms of uropathogenic Escherichia coli (UPEC), Pseudomonas aeruginosa, and Staphylococcus aureus, with up to 3.7 logs of biomass reduction. In addition, the detached biofilm cells are found sensitized to bactericidal antibiotics to the level comparable to exponential-phase planktonic cells. Based on these findings, a prototype catheter is engineered and found to remain clean for at least 30 days under the flow of artificial urine medium, while the control catheters are blocked by UPEC biofilms within 5 days.},
}
@article {pmid32371322,
year = {2020},
author = {Iannacone, F and Di Capua, F and Granata, F and Gargano, R and Esposito, G},
title = {Simultaneous nitrification, denitrification and phosphorus removal in a continuous-flow moving bed biofilm reactor alternating microaerobic and aerobic conditions.},
journal = {Bioresource technology},
volume = {310},
number = {},
pages = {123453},
doi = {10.1016/j.biortech.2020.123453},
pmid = {32371322},
issn = {1873-2976},
mesh = {Biofilms ; Bioreactors ; *Denitrification ; *Nitrification ; Nitrogen ; Phosphorus ; Sewage ; Waste Disposal, Fluid ; },
abstract = {A continuous-flow moving bed biofilm reactor (IAMBBR) alternating microaerobic and aerobic conditions was used to remove carbon, nitrogen and phosphorus through simultaneous nitrification and denitrification coupled to phosphorus removal (SNDPR). The IAMBBR was operated under different dissolved oxygen (DO) ranges (0.2-2, 0.2-3 and 0.2-4 mg L-1) and feed C/N ratios (2.8, 3.6 and 4.2) at HRT of 1 day. At a DO range of 0.2-3 mg L-1 and feed C/N ratio of 3.6, the IAMBBR achieved simultaneous removal of dissolved organic carbon (DOC), total inorganic nitrogen (TIN) and P-PO43- with average efficiencies of 100%, 62% and 75%, respectively. Illumina sequencing revealed the coexistence of nitrifiers and P-accumulating denitrifiers (e.g. Hydrogenophaga) in the IAMBBR biofilm. Batch activity tests showed that phosphorus uptake did not occur under stable anaerobic or anoxic conditions, nor under aerobic conditions in absence of nitrate.},
}
@article {pmid32371288,
year = {2020},
author = {He, L and Rong, H and Wu, D and Li, M and Wang, C and Tong, M},
title = {Influence of biofilm on the transport and deposition behaviors of nano- and micro-plastic particles in quartz sand.},
journal = {Water research},
volume = {178},
number = {},
pages = {115808},
doi = {10.1016/j.watres.2020.115808},
pmid = {32371288},
issn = {1879-2448},
mesh = {Biofilms ; Osmolar Concentration ; *Plastics ; Porosity ; *Quartz ; Sand ; Silicon Dioxide ; },
abstract = {Biofilm, community of bacteria ubiquitously present in natural environment, may interact with plastic particles and affect the transport of plastic particles in environment. The significance of biofilm (Escherichia coli) on the transport and deposition behaviors of three different sized plastic particles (0.02 μm NPs, 0.2 μm MP and 2 μm MP) were examined under both 10 mM and 50 mM NaCl solutions by comparing the breakthrough curves and retained profiles of plastic particles in bare sand versus those in biofilm-coated sand. Regardless of ionic strengths, the presence of biofilm increases the deposition of all three sized plastic particles in porous media. Via employing X-ray microtomography imaging (XMT) and Scanning electron microscope (SEM), we find that the presence of biofilm could narrow the flow path especially near to the inlet of the column and increase the surface roughness of porous media (by decreasing DLVO repulsive interaction), which contributes to the enhanced the deposition of plastic particles. Extracellular polymeric substances (EPS) present on the biofilm are found to contribute to the enhanced deposition of plastic particles. Packed column experiments, quartz crystal microbalance with dissipation (QCM-D) as well as parallel plate flow chamber experiments all show that three major components of EPS, proteins, polysaccharide, and humic substances all contribute to the enhanced deposition of plastic particles. O-H and N-H groups present on cell surfaces are highly likely to form hydrogen bond with plastic particles and increase the deposition plastic particles. Elution experiments show that decreasing solution ionic strength could release small portion of plastic particles from both bare and biofilm-coated sand columns especially from the segments near to the column inlet (with slighter lower percentage from biofilm-coated columns based on the total mass of retained plastics). In contrast, increasing flow rate does not obviously detach the plastic particles that already deposited onto porous media. The results of this study clearly show that the presence of biofilm in natural environment could enhance the deposition and decrease the transport of plastic particles.},
}
@article {pmid32369936,
year = {2020},
author = {Tseng, YK and Chen, YC and Hou, CJ and Deng, FS and Liang, SH and Hoo, SY and Hsu, CC and Ke, CL and Lin, CH},
title = {Evaluation of Biofilm Formation in Candida tropicalis Using a Silicone-Based Platform with Synthetic Urine Medium.},
journal = {Microorganisms},
volume = {8},
number = {5},
pages = {},
pmid = {32369936},
issn = {2076-2607},
support = {NTU-109L7813//National Taiwan University/ ; },
abstract = {Molecular mechanisms of biofilm formation in Candida tropicalis and current methods for biofilm analyses in this fungal pathogen are limited. (2) Methods: Biofilm biomass and crystal violet staining of the wild-type and each gene mutant strain of C. tropicalis were evaluated on silicone under synthetic urine culture conditions. (3) Results: Seven media were tested to compare the effects on biofilm growth with or without silicone. Results showed that biofilm cells of C. tropicalis were unable to form firm biofilms on the bottom of 12-well polystyrene plates. However, on a silicone-based platform, Roswell Park Memorial Institute 1640 (RPMI 1640), yeast nitrogen base (YNB) + 1% glucose, and synthetic urine media were able to induce strong biofilm growth. In particular, replacement of Spider medium with synthetic urine in the adherence step and the developmental stage is necessary to gain remarkably increased biofilms. Interestingly, unlike Candida albicans, the C. tropicalisROB1 deletion strain but not the other five biofilm-associated mutants did not cause a significant reduction in biofilm formation, suggesting that the biofilm regulatory circuits of the two species are divergent. (4) Conclusions: This system for C. tropicalis biofilm analyses will become a useful tool to unveil the biofilm regulatory network in C. tropicalis.},
}
@article {pmid32367731,
year = {2020},
author = {Lethongkam, S and Daengngam, C and Tansakul, C and Siri, R and Chumpraman, A and Phengmak, M and Voravuthikunchai, SP},
title = {Prolonged inhibitory effects against planktonic growth, adherence, and biofilm formation of pathogens causing ventilator-associated pneumonia using a novel polyamide/silver nanoparticle composite-coated endotracheal tube.},
journal = {Biofouling},
volume = {36},
number = {3},
pages = {292-307},
doi = {10.1080/08927014.2020.1759041},
pmid = {32367731},
issn = {1029-2454},
abstract = {Microbial cells can rapidly form biofilm on endotracheal tubes (ETT) causing ventilator-associated pneumonia, a serious complication in patients receiving mechanical ventilation. A novel polyamide with a good balance of hydrophilic/hydrophobic moieties was used for the embedment of green-reduction silver nanoparticles (AgNPs) for the composite-coated ETT. The films were conformal with a thickness of ∼ 17 ± 3 µm accommodating high loading of 60 ± 35 nm spherical-shaped AgNPs. The coated ETT resulted in a significant difference in reducing both planktonic growth and microbial adhesion of single and mixed-species cultures, compared with uncoated ETT (p < 0.05). A time-kill assay demonstrated rapid bactericidal effects of the coating on bacterial growth and cell adhesion to ETT surface. Biofilm formation by Pseudomonas aeruginosa and Staphylococcus aureus, commonly encountered pathogens, was inhibited by > 96% after incubation for 72 h. Polyamide/AgNP composite-coated ETT provided a broad-spectrum activity against both Gram-positive and Gram-negative bacteria as well as Candida albicans and prolonged antimicrobial activity.},
}
@article {pmid32367541,
year = {2020},
author = {Fadhlaoui, M and Laderriere, V and Lavoie, I and Fortin, C},
title = {Influence of Temperature and Nickel on Algal Biofilm Fatty Acid Composition.},
journal = {Environmental toxicology and chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1002/etc.4741},
pmid = {32367541},
issn = {1552-8618},
support = {//Fonds Québécois de la Recherche sur la Nature et les Technologies/ ; //Canada Research Chair program/ ; //Knowledge CREATE program/ ; },
abstract = {Freshwater biofilms play an important role in aquatic ecosystems and are widely used to evaluate environmental conditions. Little is known about the effects of temperature and metals on biofilm fatty acid composition. In the present study, we exposed a natural biofilm cultured in mesocosms to a gradient of nickel (Ni) concentrations at 15 and 21 °C for 28 d. Metal bioaccumulation, algal taxonomic composition, and biofilm fatty acid profiles were determined. At both temperatures, bioaccumulated Ni increased with Ni exposure concentration and reached the highest values at 25 µM Ni, followed by a decrease at 55 and 105 µM Ni. In control biofilms, palmitic acid (16:0), palmitoleic acid (16:1n7), oleic acid (18:1n9), linoleic acid (18:2n6), and linolenic acid (18:3n3) were the dominant fatty acids at 15 and 21 °C. This composition suggests a dominance of cyanobacteria and green algae, which was subsequently confirmed by microscopic observations. The increase in temperature resulted in a decrease in the ratio of unsaturated to saturated fatty acids, which is considered to be an adaptive response to temperature variation. Polyunsaturated fatty acids (PUFAs) tended to decrease along the Ni gradient, as opposed to saturated fatty acids which increased with Ni concentrations. Temperature and Ni affected differently the estimated desaturase and elongase activities (product/precursor ratios). The increase in PUFAs at 15 °C was concomitant to an increase in Δ9-desaturase (D9D). The estimated activities of D9D, Δ12-desaturase, and Δ15-desaturase decreased along the Ni gradient and reflected a decline in PUFAs. The elevated estimated elongase activity reflected the observed increase in saturated fatty acids at the highest Ni exposure concentration (105 µM). Our results suggest that fatty acids could be used as an endpoint to evaluate environmental perturbations. Environ Toxicol Chem 2020;00:1-12. © 2020 SETAC.},
}
@article {pmid32367495,
year = {2020},
author = {Punniyakotti, P and Panneerselvam, P and Perumal, D and Aruliah, R and Angaiah, S},
title = {Anti-bacterial and anti-biofilm properties of green synthesized copper nanoparticles from Cardiospermum halicacabum leaf extract.},
journal = {Bioprocess and biosystems engineering},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00449-020-02357-x},
pmid = {32367495},
issn = {1615-7605},
support = {PDF/2017/001134//Science and Engineering Research Board/ ; },
abstract = {In the present study, a copper nanoparticle (Cu NPs) was synthesized by a green synthesis method with Cardiospermum halicacabum leaf extract. The surface area of Cu NPs was measured with dynamic light scattering (DLS). UV-Vis spectrum clearly illustrates the typical absorption peak of Cu NPs. The crystalline property of Cu NPs was confirmed from the XRD pattern. TEM analysis clearly indicates the average particle size of synthesized Cu NPs was in the range of 30-40 nm with hexagonal shape. Energy-dispersive spectroscopy confirms the major strong peaks of Cu NPs. FTIR analysis confirms the existence of various functional biomolecules over the metal nanoparticles and they are playing an important role in the formation of Cu NPs. The antibacterial and anti-biofilm analyses were carried out to confirm their aptitude for biomedical applications. Interestingly, Cu NPs control the development of biofilm by attaching over the cell wall and disturb their growth and development.},
}
@article {pmid32366710,
year = {2020},
author = {Bilal, H and Bergen, PJ and Tait, JR and Wallis, SC and Peleg, AY and Roberts, JA and Oliver, A and Nation, RL and Landersdorfer, CB},
title = {Clinically Relevant Epithelial Lining Fluid Concentrations of Meropenem with Ciprofloxacin Provide Synergistic Killing and Resistance Suppression of Hypermutable Pseudomonas aeruginosa in a Dynamic Biofilm Model.},
journal = {Antimicrobial agents and chemotherapy},
volume = {64},
number = {7},
pages = {},
doi = {10.1128/AAC.00469-20},
pmid = {32366710},
issn = {1098-6596},
abstract = {Treatment of exacerbations of chronic Pseudomonas aeruginosa infections in patients with cystic fibrosis (CF) is highly challenging due to hypermutability, biofilm formation, and an increased risk of resistance emergence. We evaluated the impact of ciprofloxacin and meropenem as monotherapy and in combination in the dynamic in vitro CDC biofilm reactor (CBR). Two hypermutable P. aeruginosa strains, PAOΔmutS (MIC of ciprofloxacin [MICciprofloxacin], 0.25 mg/liter; MICmeropenem, 2 mg/liter) and CW44 (MICciprofloxacin, 0.5 mg/liter; MICmeropenem, 4 mg/liter), were investigated for 120 h. Concentration-time profiles achievable in epithelial lining fluid (ELF) following FDA-approved doses were simulated in the CBR. Treatments were ciprofloxacin at 0.4 g every 8 h as 1-h infusions (80% ELF penetration), meropenem at 6 g/day as a continuous infusion (CI) (30% and 60% ELF penetration), and their combinations. Counts of total and less-susceptible planktonic and biofilm bacteria and MICs were determined. Antibiotic concentrations were quantified by an ultrahigh-performance liquid chromatography photodiode array (UHPLC-PDA) assay. For both strains, all monotherapies failed, with substantial regrowth and resistance of planktonic (≥8 log10 CFU/ml) and biofilm (>8 log10 CFU/cm2) bacteria at 120 h (MICciprofloxacin, up to 8 mg/liter; MICmeropenem, up to 64 mg/liter). Both combination treatments demonstrated synergistic bacterial killing of planktonic and biofilm bacteria of both strains from ∼48 h onwards and suppressed regrowth to ≤4 log10 CFU/ml and ≤6 log10 CFU/cm2 at 120 h. Overall, both combination treatments suppressed the amplification of resistance of planktonic bacteria for both strains and of biofilm bacteria for CW44. The combination with meropenem at 60% ELF penetration also suppressed the amplification of resistance of biofilm bacteria for PAOΔmutS Thus, combination treatment demonstrated synergistic bacterial killing and resistance suppression against difficult-to-treat hypermutable P. aeruginosa strains.},
}
@article {pmid32366054,
year = {2020},
author = {Kabel, KI and Labena, A and Keshawy, M and Hozzein, WN},
title = {Progressive Applications of Hyperbranched Polymer Based on Diarylamine: Antimicrobial, Anti-Biofilm and Anti-Aerobic Corrosion.},
journal = {Materials (Basel, Switzerland)},
volume = {13},
number = {9},
pages = {},
pmid = {32366054},
issn = {1996-1944},
support = {RSP-2019/53//King Saud University/ ; },
abstract = {New generations of hyperbranched aramids were synthesized from diarylamine and methyl acrylate using an AB2 monomer approach in a straightforward one-pot preparation. The chemical structure of hyperbranched Phenylenediamine/Methyl Acrylate HB(PDMA was confirmed by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (1HNMR) spectroscopy. In addition, the particle's size and distribution were recorded using Dynamic Light Scattering (DLS). Moreover, the synthesized HB(PDMA)s displayed broad-spectrum antimicrobial activities against Gram-positive and Gram-negative bacteria as well as yeast strains and anti-biofilm activity where the highest activity was attributed to HB(PDMA)G4 at the lowest Minimum Inhibitory, Minimum Bactericidal, and Fungicidal Concentrations (MIC, MBC, and MFC, respectively). Furthermore, the HB(PDMA)s expressed anti-bacterial activity against isolated Pseudomonas sp. (R301) at a salinity of 35,000 ppm (NaCl). In addition, they revealed different corrosion inhibition efficiencies at the cultivated medium salinity at the estimated minimum bactericidal concentrations. The highest metal corrosion inhibition efficiencies were 59.5 and 94.3% for HB(PDMA)G4 at the Minimum Bactericidal Concentrations (MBCs) and two times Minimum Bactericidal Concentrations (2XMBCs), respectively, in comparison to both negative and positive controls.},
}
@article {pmid32365789,
year = {2020},
author = {Whelan, S and O'Grady, MC and Corcoran, D and Finn, K and Lucey, B},
title = {Uropathogenic Escherichia coli Biofilm-Forming Capabilities are not Predictable from Clinical Details or from Colonial Morphology.},
journal = {Diseases (Basel, Switzerland)},
volume = {8},
number = {2},
pages = {},
doi = {10.3390/diseases8020011},
pmid = {32365789},
issn = {2079-9721},
support = {RISAM_SW_2018//Cork Institute of Technology/ ; },
abstract = {Antibiotic resistance is increasing to an extent where efficacy is not guaranteed when treating infection. Biofilm formation has been shown to complicate treatment, whereby the formation of biofilm is associated with higher minimum inhibitory concentration values of antibiotic. The objective of the current paper was to determine whether biofilm formation is variable among uropathogenic Escherichia coli isolates and whether formation is associated with recurrent urinary tract infection (UTI), and whether it can be predicted by phenotypic appearance on culture medium A total of 62 E. coli isolates that were reported as the causative agent of UTI were studied (33 from patients denoted as having recurrent UTI and 29 from patients not specified as having recurrent UTI). The biofilm forming capability was determined using a standard microtitre plate method, using E. coli ATCC 25922 as the positive control. The majority of isolates (93.6%) were found to be biofilm formers, whereby 81% were denoted as strong or very strong producers of biofilm when compared to the positive control. Through the use of a Wilcox test, the difference in biofilm forming propensity between the two patient populations was found to not be statistically significant (p = 0.5). Furthermore, it was noted that colony morphology was not a reliable predictor of biofilm-forming propensity. The findings of this study indicate that biofilm formation is very common among uropathogens, and they suggest that the biofilm-forming capability might be considered when treating UTI. Clinical details indicating a recurrent infection were not predictors of biofilm formation.},
}
@article {pmid32365462,
year = {2020},
author = {Alves, P and Gomes, LC and Rodríguez-Emmenegger, C and Mergulhão, FJ},
title = {Efficacy of A Poly(MeOEGMA) Brush on the Prevention of Escherichia coli Biofilm Formation and Susceptibility.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {9},
number = {5},
pages = {},
pmid = {32365462},
issn = {2079-6382},
support = {346972946//Deutsche Forschungsgemeinschaft/ ; UIDB/00511/2020//Fundação para a Ciência e a Tecnologia/ ; PD/BD/114317/2016//Fundação para a Ciência e a Tecnologia/ ; CEECIND/01700/2017//Fundação para a Ciência e a Tecnologia/ ; 19893 N//Forschungskuratorium Textil, Bundesministerium für Wirtschaft und Energie/ ; },
abstract = {Urinary tract infections are one of the most common hospital-acquired infections, and they are often associated with biofilm formation in indwelling medical devices such as catheters and stents. This study aims to investigate the antibiofilm performance of a polymer brush-poly[oligo(ethylene glycol) methyl ether methacrylate], poly(MeOEGMA)-and evaluate its effect on the antimicrobial susceptibility of Escherichia coli biofilms formed on that surface. Biofilms were formed in a parallel plate flow chamber (PPFC) for 24 h under the hydrodynamic conditions prevailing in urinary catheters and stents and challenged with ampicillin. Results obtained with the brush were compared to those obtained with two control surfaces, polydimethylsiloxane (PDMS) and glass. The polymer brush reduced by 57% the surface area covered by E. coli after 24 h, as well as the number of total adhered cells. The antibiotic treatment potentiated cell death and removal, and the total cell number was reduced by 88%. Biofilms adapted their architecture, and cell morphology changed to a more elongated form during that period. This work suggests that the poly(MeOEGMA) brush has potential to prevent bacterial adhesion in urinary tract devices like ureteral stents and catheters, as well as in eradicating biofilms developed in these biomedical devices.},
}
@article {pmid32365130,
year = {2020},
author = {De Natale, A and Mele, BH and Cennamo, P and Del Mondo, A and Petraretti, M and Pollio, A},
title = {Microbial biofilm community structure and composition on the lithic substrates of Herculaneum Suburban Baths.},
journal = {PloS one},
volume = {15},
number = {5},
pages = {e0232512},
pmid = {32365130},
issn = {1932-6203},
abstract = {In this work, we want to investigate the impact of different substrates and different environmental condition on the biofilm communities growing on plaster, marble, and mortar substrates inside the Herculaneum Suburban Baths. To do so, we measured environmental conditions and sampled biofilm communities along the walls of the baths and used culture-dependent and -independent molecular techniques (DGGE) to identify the species at each sampling sites. We used the species pool to infer structure and richness of communities within each site in each substrate, and confocal light scanning microscopy to assess the three-dimensional structure of the sampled biofilms. To gather further insights, we built a meta-community network and used its local realizations to analyze co-occurrence patterns of species. We found that light is a limiting factor in the baths environment, that moving along sites equals moving along an irradiation gradient, and that such gradient shapes the community structure, de facto separating a dark community, rich in Bacteria, Fungi and cyanobacteria, from two dim communities, rich in Chlorophyta. Almost all sites are dominated by photoautotrophs, with Fungi and Bacteria relegated to the role of rare species., and structural properties of biofilms are not consistent within the same substrate. We conclude that the Herculaneum suburban baths are an environment-shaped community, where one dark community (plaster) and one dim community (mortar) provides species to a &quot;midway&quot; community (marble).},
}
@article {pmid32363762,
year = {2020},
author = {Vera-González, N and Bailey-Hytholt, CM and Langlois, L and de Camargo Ribeiro, F and de Souza Santos, EL and Junqueira, JC and Shukla, A},
title = {Anidulafungin liposome nanoparticles exhibit antifungal activity against planktonic and biofilm Candida albicans.},
journal = {Journal of biomedical materials research. Part A},
volume = {},
number = {},
pages = {},
doi = {10.1002/jbm.a.36984},
pmid = {32363762},
issn = {1552-4965},
support = {1644760//National Science Foundation/ ; N000141712651//Office of Naval Research/ ; },
abstract = {Fungal infections can cause significant patient morbidity and mortality. Nanoparticle therapeutics have the potential to improve treatment of these infections. Here we report the development of liposomal nanoparticles incorporating anidulafungin, a potent antifungal, with the goal of increasing its solubility and aiding in localization to fungi. Liposomes were fabricated with three concentrations of anidulafungin yielding monodisperse ~100 nm unilamellar vesicles. All three formulations inhibited planktonic Candida albicans growth at a minimum inhibitory concentration equivalent to free drug. All three formulations also disrupted preformed C. albicans biofilms, reducing fungal burden by as much as 99%, exhibiting superior biofilm disruption compared with free drug. Liposome formulations tested in vivo in C. albicans infected Galleria mellonella wax moth larvae demonstrated increased survival compared to free drug equivalents, leading to a survival of 33 to 67% of larvae over 7 days depending on the liposome utilized compared with only 25% survival of larvae administered free drug. Liposomal formulations along with free anidulafungin did not cause red blood cell lysis. Ultimately, the liposome formulations reported here increased anidulafungin solubility, displayed promising efficacy against planktonic and biofilm C. albicans, and improved the survival of C. albicans-infected G. mellonella compared to free anidulafungin.},
}
@article {pmid32362877,
year = {2020},
author = {Žiemytė, M and Rodríguez-Díaz, JC and Ventero, MP and Mira, A and Ferrer, MD},
title = {Effect of Dalbavancin on Staphylococcal Biofilms When Administered Alone or in Combination With Biofilm-Detaching Compounds.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {553},
pmid = {32362877},
issn = {1664-302X},
abstract = {Microorganisms grown in biofilms are more resistant to antimicrobial treatment and immune system attacks compared to their planktonic forms. In fact, infections caused by biofilm-forming Staphylococcus aureus and Staphylococcus epidermidis are a large threat for public health, including patients with medical devices. The aim of the current manuscript was to test the effect of dalbavancin, a recently developed lipoglycopeptide antibiotic, alone or in combination with compounds contributing to bacterial cell disaggregation, on staphylococcal biofilm formation and elimination. We used real-time impedance measurements in microtiter plates to study biofilm growth dynamics of S. aureus and S. epidermidis strains, in the absence or presence of dalbavancin, linezolid, vancomycin, cloxacillin, and rifampicin. Further experiments were undertaken to check whether biofilm-detaching compounds such as N-acetylcysteine (NAC) and ficin could enhance dalbavancin efficiency. Real-time dose-response experiments showed that dalbavancin is a highly effective antimicrobial, preventing staphylococcal biofilm formation at low concentrations. Minimum biofilm inhibitory concentrations were up to 22 higher compared to standard E-test values. Dalbavancin was the only antimicrobial that could halt new biofilm formation on established biofilms compared to the other four antibiotics. The addition of NAC decreased dalbavancin efficacy while the combination of dalbavancin with ficin was more efficient than antibiotic alone in preventing growth once the biofilm was established. Results were confirmed by classical biofilm quantification methods such as crystal violet (CV) staining and viable colony counting. Thus, our data support the use of dalbavancin as a promising antimicrobial to treat biofilm-related infections. Our data also highlight that synergistic and antagonistic effects between antibiotics and biofilm-detaching compounds should be carefully tested in order to achieve an efficient treatment that could prevent both biofilm formation and disruption.},
}
@article {pmid32360467,
year = {2020},
author = {Valliammai, A and Sethupathy, S and Ananthi, S and Priya, A and Selvaraj, A and Nivetha, V and Aravindraja, C and Mahalingam, S and Pandian, SK},
title = {Proteomic profiling unveils citral modulating expression of IsaA, CodY and SaeS to inhibit biofilm and virulence in methicillin-resistant Staphylococcus aureus.},
journal = {International journal of biological macromolecules},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijbiomac.2020.04.231},
pmid = {32360467},
issn = {1879-0003},
abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is one of the dangerous human pathogens and it is categorized as a high priority multi-drug resistant bacterium by WHO. Biofilm forming ability of MRSA is responsible for persistent infections and also difficult to eradicate using antibiotic therapy as biofilm is much more resistant to antibiotics. Thus, targeting biofilm and virulence has become an alternative approach to attenuate the pathogenicity of bacterium without affecting the growth. Hence, the present study was aimed at evaluation of antibiofilm potential of citral against MRSA and to decode the possible mode of action. Citral inhibited biofilm formation by MRSA without affecting growth at 100 μg/mL. Microscopic analyses evidenced that citral greatly hampered the surface adherence of MRSA. Effect of citral on cellular proteome of MRSA was studied using two-dimensional gel electrophoresis (2DGE) and differentially regulated proteins were identified using nano LC-MS/MS and MALDI-TOF/TOF analysis. Gene ontology and STRING analysis revealed that citral differentially regulated the proteins involved in pleotropic transcriptional repression (CodY), cell wall homeostasis (IsaA), regulation of exotoxin secretion (SaeS), cell adhesion, hemolysis, capsular polysaccharide biosynthesis and pathogenesis. Gene expression analysis and in vitro assays further validated the alteration in synthesis of slime, hemolysin, lipase, staphyloxanthin and oxidant susceptibility. Thus, the present study unveiled the multiple protein targeted antibiofilm potential of citral and portrays citral as a promising therapeutic agent to combat biofilm mediated MRSA infections with less possibility of resistance development.},
}
@article {pmid32360272,
year = {2020},
author = {Vitorino, I and Albuquerque, L and Wiegand, S and Kallscheuer, N and da Costa, MS and Lobo-da-Cunha, A and Jogler, C and Lage, OM},
title = {Alienimonas chondri sp. nov., a novel planctomycete isolated from the biofilm of the red alga Chondrus crispus.},
journal = {Systematic and applied microbiology},
volume = {43},
number = {3},
pages = {126083},
doi = {10.1016/j.syapm.2020.126083},
pmid = {32360272},
issn = {1618-0984},
abstract = {The phylum Planctomycetes comprises bacteria with peculiar and very unique characteristics among prokaryotes. In marine environments, macroalgae biofilms are well known for harboring planctomycetal diversity. Here, we describe a novel isolate obtained from the biofilm of the red alga Chondrus crispus collected at a rocky beach in Porto, Portugal. The novel strain LzC2T is motile, rosette-forming with spherical- to ovoid-shaped cells. LzC2T forms magenta- to pinkish-colored colonies in M13 and M14 media. Transmission and scanning electron microscopy observations showed a division by polar and lateral budding. Mother cells are connected to the daughter cells by a tubular neck-like structure. The strain requires salt for growth. Vitamins are not required for growth. Optimal growth occurs from 15 to 30°C and within a pH range from 5.5 to 10.0. Major fatty acids are anteiso-C15:0 (54.2%) and iso-C15:0 (19.5%). Phosphatidylglycerol, diphosphatidylglycerol and an unidentified glycolipid represent the main lipids and menaquinone 6 (MK-6) is the only quinone present. 16S rRNA gene-based phylogenetic analysis supports the affiliation to the phylum Planctomycetes and family Planctomycetaceae, with Alienimonas as the closest relative. Strain LzC2T shares 97% 16S rRNA gene sequence similarity with Alienimonas californiensis. LzC2T has a genome size of 5.3 Mb and a G+C content of 68.3%. Genotypic and phenotypic comparison with the closest relatives strongly suggest that LzC2T (=CECT 30038T=LMG XXXT) is a new species of the genus Alienimonas, for which we propose the name Alienimonas chondri sp. nov., represented by LzC2T as type strain. 16S rRNA gene accession number: GenBank=MN757873.1. Genome accession number: GenBank=WTPX00000000.},
}
@article {pmid32358981,
year = {2020},
author = {El-Chami, MF and Mayotte, J and Bonner, M and Holbrook, R and Stromberg, K and Sohail, MR},
title = {Response to the letter to the editor: Wettability and roughness: Important determinants of bacterial adhesion and biofilm formation.},
journal = {Journal of cardiovascular electrophysiology},
volume = {31},
number = {7},
pages = {1886-1887},
doi = {10.1111/jce.14517},
pmid = {32358981},
issn = {1540-8167},
}
@article {pmid32358834,
year = {2020},
author = {Campbell, M and Fathi, R and Cheng, SY and Ho, A and Gilbert, ES},
title = {Rhamnus prinoides (gesho) stem extract prevents co-culture biofilm formation by Streptococcus mutans and Candida albicans.},
journal = {Letters in applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/lam.13307},
pmid = {32358834},
issn = {1472-765X},
abstract = {Streptococcus mutans and Candida albicans exhibit a symbiotic relationship to form polymicrobial biofilms that exacerbate oral infections including early-childhood caries, periodontitis and candidiasis. Rhamnus prinoides (gesho) has traditionally been used for the treatment of a variety of illnesses and was recently found to inhibit Gram-positive bacterial biofilm formation. We hypothesized that Rhamnus prinoides extracts have anti-biofilm activity against S. mutans and C. albicans mono- and dual-species biofilms. Ethanol extracts were prepared from gesho stems and leaves; then anti-biofilm activity was assessed using crystal violet, resazurin and XTT staining. Ethanol extracts significantly inhibited Streptococcus mutans and Candida albicans mono-species biofilm formation up to 97 and 75%, respectively. The stem ethanol extract disrupted S. mutans and C. albicans co-culture synergism, with 98% less polymicrobial biofilm formation than the untreated control. Additionally, this extract inhibited planktonic S. mutans cell growth and decreased biofilm polysaccharide production up to 99%. The reduction in polysaccharide production is likely a contributing factor in the anti-biofilm activity of GSE. These findings indicate that gesho or gesho-derived compounds may have potential as additives to oral hygiene products.},
}
@article {pmid32357560,
year = {2020},
author = {Estevez, MB and Raffaelli, S and Mitchell, SG and Faccio, R and Alborés, S},
title = {Biofilm Eradication Using Biogenic Silver Nanoparticles.},
journal = {Molecules (Basel, Switzerland)},
volume = {25},
number = {9},
pages = {},
pmid = {32357560},
issn = {1420-3049},
abstract = {Microorganisms offer an alternative green and scalable technology for the synthesis of value added products. Fungi secrete high quantities of bioactive substances, which play dual-functional roles as both reducing and stabilizing agents in the synthesis of colloidal metal nanoparticles such as silver nanoparticles, which display potent antimicrobial properties that can be harnessed for a number of industrial applications. The aim of this work was the production of silver nanoparticles using the extracellular cell free extracts of Phanerochaete chrysosporium, and to evaluate their activity as antimicrobial and antibiofilm agents. The 45-nm diameter silver nanoparticles synthesized using this methodology possessed a high negative surface charge close to -30 mV and showed colloidal stability from pH 3-9 and under conditions of high ionic strength ([NaCl] = 10-500 mM). A combination of environmental SEM, TEM, and confocal Raman microscopy was used to study the nanoparticle-E. coli interactions to gain a first insight into their antimicrobial mechanisms. Raman data demonstrate a significant decrease in the fatty acid content of E. coli cells, which suggests a loss of the cell membrane integrity after exposure to the PchNPs, which is also commensurate with ESEM and TEM images. Additionally, these biogenic PchNPs displayed biofilm disruption activity for the eradication of E. coli and C. albicans biofilms.},
}
@article {pmid32357268,
year = {2020},
author = {Purkait, S and Bhattacharya, A and Bag, A and Chattopadhyay, RR},
title = {Evaluation of antibiofilm efficacy of essential oil components β-caryophyllene, cinnamaldehyde and eugenol alone and in combination against biofilm formation and preformed biofilms of Listeria monocytogenes and Salmonella typhimurium.},
journal = {Letters in applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/lam.13308},
pmid = {32357268},
issn = {1472-765X},
abstract = {The aim of this study was to examine whether the process of initial colonization and the formation of mature biofilm structure of foodborne bacterial pathogens Listeria monocytogenes and Salmonella typhimurium can be impeded by active essential oil components β-caryophyllene, cinnamaldehyde and eugenol at their individual and combined effects. Among the essential oil components tested, cinnamaldehyde and eugenol at their individual effect showed >50% degradation in biofilm biomass against preformed (matured) biofilms of both the studied bacteria, whereas β-caryophyllene failed to do so. In combination, cinnamaldehyde/eugenol blend showed synergistic antibiofilm efficacy against preformed biofilms of both the studied bacteria L. monocytogenes (FICI: 0·24) and S. typhimurium (FICI: 0·40), whereas other tested combinations showed additive antibiofilm efficacy with FICI ranged from 2·02 to 2·35. Essential oil components alone and in combination also showed much higher inhibition effect on biofilm formation at the initial stage compared to their inhibition effect on preformed biofilms. The results provide evidence that cinnamaldehyde/eugenol combination may help in designing a more potent novel, natural antibiofilm blend at sufficiently low concentrations in the food and pharmaceutical industries.},
}
@article {pmid32356400,
year = {2020},
author = {Cay, S and Ozeke, O and Ozcan, F and Topaloglu, S and Aras, D},
title = {Wettability and roughness: Important determinants of bacterial adhesion and biofilm formation.},
journal = {Journal of cardiovascular electrophysiology},
volume = {31},
number = {7},
pages = {1885},
doi = {10.1111/jce.14515},
pmid = {32356400},
issn = {1540-8167},
}
@article {pmid32355781,
year = {2020},
author = {Xiang, B and Lei, Y and Chen, Y and Zhao, G and Zhou, Y and Zhou, Y and Huang, Y and Ye, L},
title = {Mechanistic study on the inhibition of Staphylococcus epidermidis biofilm by agrC-specific binding polypeptide.},
journal = {Annals of translational medicine},
volume = {8},
number = {6},
pages = {337},
pmid = {32355781},
issn = {2305-5839},
abstract = {Background: Considering the wide-spread misuse of antibiotics, the development of new antibacterial drugs may effectively prevent the emergence of antibiotic resistance in bacteria. The understanding of the mechanism underlying the Staphylococcus epidermidis agrC-specific binding polypeptide-mediated inhibition of S. epidermidis biofilm formation may supply ideas for the development of new antibacterial drugs.<br><br>Methods: S. epidermidis cells were cultured with different concentrations (0, 100, 200, 400, 800, and 1,600 µg/mL) of agrC-specific binding polypeptide (N1) and blank (N0). Crystal violet staining was performed to test the formation of biofilms and to determine the best concentration of agrC-specific binding polypeptides, and the bacterial inhibitory concentration was also determined. At different time points (6, 12, 18, 24, and 30 h), XTT assay was used to measure bacterial viability, and the real-time quantitative polymerase chain reaction was performed to measure the expression of atlE, icaA, fbe, and icaR genes. The sulfuric acid-phenol method was used to determine polysaccharide intercellular adhesin (PIA) levels.<br><br>Results: The biofilm formation ability of S. epidermidis was the lowest after treatment with 800 µg/mL agrC-specific binding polypeptide. After 6 h of culture, agrC-specific binding polypeptide upregulated the expression of atlE, icaA, fbe, and icaR and increased the bacterial viability. However, the polypeptide downregulated the expression of atlE, icaA, fbe, and icaR and inhibited S. epidermidis growth and PIA formation after 12 h of culture. Although agrC-specific binding polypeptide upregulated the expression of atlE, icaA, fbe, and icaR after 18 h, they inhibited bacterial growth and PIA formation.<br><br>Conclusions: Thus, agrC-specific binding polypeptide could downregulate the expression of atlE, icaA, fbe, and icaR and inhibit PIA formation by S. epidermidis after 12 h, demonstrating its transient inhibitory effects on the biofilm formation ability of S. epidermidis. Its effective concentration was 800 µg/mL.},
}
@article {pmid32355001,
year = {2020},
author = {Gallego-Hernandez, AL and DePas, WH and Park, JH and Teschler, JK and Hartmann, R and Jeckel, H and Drescher, K and Beyhan, S and Newman, DK and Yildiz, FH},
title = {Upregulation of virulence genes promotes Vibrio cholerae biofilm hyperinfectivity.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {117},
number = {20},
pages = {11010-11017},
pmid = {32355001},
issn = {1091-6490},
support = {R01 HL117328/HL/NHLBI NIH HHS/United States ; S10 OD023528/OD/NIH HHS/United States ; R01 AI114261/AI/NIAID NIH HHS/United States ; R01 AI102584/AI/NIAID NIH HHS/United States ; R01 AI127850/AI/NIAID NIH HHS/United States ; R01 AI055987/AI/NIAID NIH HHS/United States ; },
abstract = {Vibrio cholerae remains a major global health threat, disproportionately impacting parts of the world without adequate infrastructure and sanitation resources. In aquatic environments, V. cholerae exists both as planktonic cells and as biofilms, which are held together by an extracellular matrix. V. cholerae biofilms have been shown to be hyperinfective, but the mechanism of hyperinfectivity is unclear. Here we show that biofilm-grown cells, irrespective of the surfaces on which they are formed, are able to markedly outcompete planktonic-grown cells in the infant mouse. Using an imaging technique designed to render intestinal tissue optically transparent and preserve the spatial integrity of infected intestines, we reveal and compare three-dimensional V. cholerae colonization patterns of planktonic-grown and biofilm-grown cells. Quantitative image analyses show that V. cholerae colonizes mainly the medial portion of the small intestine and that both the abundance and localization patterns of biofilm-grown cells differ from that of planktonic-grown cells. In vitro biofilm-grown cells activate expression of the virulence cascade, including the toxin coregulated pilus (TCP), and are able to acquire the cholera toxin-carrying CTXФ phage. Overall, virulence factor gene expression is also higher in vivo when infected with biofilm-grown cells, and modulation of their regulation is sufficient to cause the biofilm hyperinfectivity phenotype. Together, these results indicate that the altered biogeography of biofilm-grown cells and their enhanced production of virulence factors in the intestine underpin the biofilm hyperinfectivity phenotype.},
}
@article {pmid32354252,
year = {2020},
author = {Mohamed, MSM and Mostafa, HM and Mohamed, SH and Abd El-Moez, SI and Kamel, Z},
title = {Combination of Silver Nanoparticles and Vancomycin to Overcome Antibiotic Resistance in Planktonic/Biofilm Cell from Clinical and Animal Source.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2020.0089},
pmid = {32354252},
issn = {1931-8448},
abstract = {This study aims to evaluate the prevalence of multidrug-resistant (MDR) and biofilm-forming pathogens from animal source compared to clinical ones. In addition, to assess the antibacterial and antibiofilm activity of silver nanoparticles (AgNPs) alone and/or mixed with vancomycin. Out of 62 bacterial isolates from animal respiratory tract infection (RTI), 50.00% were defined as MDR, while among human ones, 44.00% were MDR. The bacteria Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus pneumoniae were the predominant isolated bacteria from both animal and human origin with frequency percentage of 50.00, 22.32, and 18.75, respectively. Among Staph. aureus strains, mecA gene was detected in 60.00% and 61.54% of animal and human isolates, respectively, while mecALGA251 (mecC) gene was detected in 13.33% and 15.38% of animal and human isolates, respectively. Biofilm formation ability among animal isolates was 83.87%, while among human ones was 86.00%. AgNPs were effective in inhibiting planktonic cells with minimal inhibitory concentration (MIC) values (0.625-10 μg/mL), as well as eradicating biofilm with minimal biofilm eradication concentration values (1.25-10 μg/mL). Noticeable low MIC of AgNPs was required for the isolates from animal source (0.625-5 μg/mL) compared to clinical ones (0.625-10 μg/mL). Remarkable reduction in AgNP effective concentration was observed after combination with 1/4 MIC of vancomycin with minimum recorded concentration of 0.08 μg/mL. In conclusion, the prevalence of MDR among RT pathogens was recorded with high ability to produce biofilm and virulence factors from both animal and human pathogens. AgNPs showed strong antibacterial and antibiofilm activity alone and mixed with vancomycin, with up to fourfold reduction of AgNP inhibitory dose.},
}
@article {pmid32353392,
year = {2020},
author = {Lakshmi, SA and Bhaskar, JP and Krishnan, V and Sethupathy, S and Pandipriya, S and Aruni, W and Pandian, SK},
title = {Inhibition of biofilm and biofilm-associated virulence factor production in methicillin-resistant Staphylococcus aureus by docosanol.},
journal = {Journal of biotechnology},
volume = {317},
number = {},
pages = {59-69},
doi = {10.1016/j.jbiotec.2020.04.014},
pmid = {32353392},
issn = {1873-4863},
abstract = {Antimicrobial resistance is a major public health concern in infection control. Hence, a multi-pronged approach is necessary to curb the severity of infections. The present study entails the identification of docosanol (fatty alcohol) from Streptomyces as a novel antibiofilm agent which can target the virulence factors of MRSA. Results showed that docosanol as a potent antibiofilm agent and found to inhibit several virulence factors of MRSA. The antibiofilm efficacy of docosanol analyzed through light and scanning electron microscopy showed a significant reduction in adherent cells. Moreover, analysis of three-dimensional structure of biofilm matrix by confocal laser scanning microscope demonstrated effective antibiofilm potential of docosanol. In addition, docosanol reduced the survival rate of MRSA in healthy human blood and enhanced the neutrophil-mediated killing by interfering with hemolysin production. RT-qPCR analysis revealed the down regulation of several virulence genes, possibly by affecting the expression of the accessory gene regulator (agr) system and transcriptional regulator sarA. These findings suggest that docosanol could effectively reduce the biofilm phenotype and virulence production, and thus becomes a promising candidate to treat MRSA infections.},
}
@article {pmid32352767,
year = {2020},
author = {Coutaud, M and Paule, A and Méheut, M and Viers, J and Rols, JL and Pokrovsky, OS},
title = {Elemental and Isotopic Variations of Copper and Zinc Associated with the Diel Activity of Phototrophic Biofilm.},
journal = {Environmental science &amp; technology},
volume = {54},
number = {11},
pages = {6741-6750},
doi = {10.1021/acs.est.0c00733},
pmid = {32352767},
issn = {1520-5851},
abstract = {The response in metal concentrations and isotopic composition to variations in photosynthetic activity of aquatic micro-organisms is crucially important for understanding the environmental controls on metal fluxes and isotope excursions. Here we studied the impacts of two successive diel cycles on physicochemical parameters, Cu and Zn concentrations, and isotopic composition in solution in the presence of mature phototrophic biofilm in a rotating annular bioreactor. The diel cycles induced fluctuations in temperature, pH, and dissolved oxygen concentration following the variation in the photosynthesis activity of the biofilm. Diel variations in metal concentrations were primarily related to the pH variation, with an increase in metal concentration in solution related to a pH decrease. For both metals, δ(66Zn) and δ(65Cu) in solution exhibited complex but reproducible diel cycles. Diel variations in photosynthetic activity led to alternatively positive and negative isotope fractionation, producing the sorption of light Zn (Δ(66Znsorbed-solution) = -0.1 ± 0.06‰) and heavy Cu isotopes (Δ(65Cusorbed-solution) = +0.17 ± 0.06‰) during the day at high pH and the excretion of lighter Zn isotopes (-0.4‰ < Δ(66Znexcreted-biofilm) < +0.14‰) and heavy Cu isotopes (Δ(65Cuexcreted-biofilm) = +0.7 ± 0.3‰) during the night at lower pH. We interpreted Zn and Cu diel cycles as a combination of a desorption of exopolymeric substance-metal complexes and a small active efflux during the night with adsorption and incorporation via an active uptake during the day. The hysteresis of metal concentration in solution over the diel cycle suggested the more important role of uptake compared to desorption and efflux from the biofilm. The phototrophic biofilm presents a non-negligible highly labile metal pool with important potential for contrasting isotopic fractionation at the diel scale.},
}
@article {pmid32352288,
year = {2020},
author = {Wu, Y and Luo, X and Qin, B and Li, F and Häggblom, MM and Liu, T},
title = {Enhanced Current Production by Exogenous Electron Mediators via Synergy of Promoting Biofilm Formation and the Electron Shuttling Process.},
journal = {Environmental science &amp; technology},
volume = {54},
number = {12},
pages = {7217-7225},
doi = {10.1021/acs.est.0c00141},
pmid = {32352288},
issn = {1520-5851},
abstract = {Exogenous electron mediators (EMs) can facilitate extracellular electron transfer (EET) via electron shuttling processes, but it is still unclear whether and how biofilm formation is affected by the presence of EMs. Here, the impacts of EMs on EET and biofilm formation were investigated in bioelectrochemical systems (BESs) with Shewanella oneidensis MR-1, and the results showed that the presence of five different EMs led to high density current production. All the EMs substantially promoted biofilm formation with 15-36 times higher total biofilm DNA with EMs than without EMs, and they also increased the production of extracellular polymeric substances, which was favorable for biofilm formation. The current decreased substantially after removing EMs from the medium or by replacing electrodes without biofilm, suggesting that both biofilm and EMs are required for high density current production. EET-related gene expression was upregulated with EMs, resulting in the high flux of cell electron output. A synergistic mechanism was proposed: EMs in suspension were quickly reduced by the cells and reoxidized rapidly by the electrode, resulting in a microenvironment with sufficient oxidized EMs for biofilm formation, and thus, besides the well-known electron shuttling process, the EM-induced high biofilm formation and high Mtr gene expression could jointly contribute to the EET and subsequently produce a high density current. This study provides a new insight into EM-enhanced current production via regulating the biofilm formation and EET-related gene expression.},
}
@article {pmid32351494,
year = {2020},
author = {Tkhilaishvili, T and Wang, L and Perka, C and Trampuz, A and Gonzalez Moreno, M},
title = {Using Bacteriophages as a Trojan Horse to the Killing of Dual-Species Biofilm Formed by Pseudomonas aeruginosa and Methicillin Resistant Staphylococcus aureus.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {695},
doi = {10.3389/fmicb.2020.00695},
pmid = {32351494},
issn = {1664-302X},
abstract = {Pseudomonas aeruginosa and Staphylococcus aureus are pathogens able to colonize surfaces and form together a mixed biofilm. Dual-species biofilms are significantly more resistant to antimicrobials than a monomicrobial community, leading to treatment failure. Due to their rapid bactericidal activity, the self-amplification ability and the biofilm degrading properties, bacteriophages represent a promising therapeutic option in fighting biofilm-related infections. In this study, we investigated the effect of either the simultaneous or staggered application of commercially available phages and ciprofloxacin versus S. aureus/P. aeruginosa dual-species biofilms in vitro. Biofilms were grown on porous glass beads and analyzed over time. Different techniques such as microcalorimetry, sonication and scanning electron microscopy were combined for the evaluation of anti-biofilm activities. Both bacterial species were susceptible to ciprofloxacin and to phages in their planktonic form of growth. Ciprofloxacin tested alone against biofilms required high concentration ranging from 256 to >512 mg/L to show an inhibitory effect, whereas phages alone showed good and moderate activity against MRSA biofilms and dual-species biofilms, respectively, but low activity against P. aeruginosa biofilms. The combination of ciprofloxacin with phages showed a remarkable improvement in the anti-biofilm activity of both antimicrobials with complete eradication of dual-species biofilms after staggered exposure to Pyophage or Pyophage + Staphylococcal phage for 12 h followed by 1 mg/L of ciprofloxacin, a dose achievable by intravenous or oral antibiotic administration. Our study provides also valuable data regarding not only dosage but also an optimal time of antimicrobial exposure, which is crucial in the implementation of combined therapies.},
}
@article {pmid32350966,
year = {2020},
author = {Dygico, LK and Gahan, CGM and Grogan, H and Burgess, CM},
title = {Examining the efficacy of mushroom industry biocides on Listeria monocytogenes biofilm.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14681},
pmid = {32350966},
issn = {1365-2672},
abstract = {AIMS: The aim of this study was to test the efficacy of new and currently used biocides in the mushroom industry for inactivating L. monocytogenes biofilm.<br><br>METHODS AND RESULTS: A lab-scale study was initially carried out to test the efficacy of eleven biocidal products against a cocktail of five L. monocytogenes strains that were grown to three-day biofilms on stainless steel coupons. Biocidal efficacy was then tested under clean and dirty conditions based on the EN 13697:2015 method. The results for the biocides tested ranged between 1.7-log to 6-log reduction of biofilm, with only the efficacy of the sodium hypochlorite-based biocide being significantly reduced in dirty conditions. A pilot-scale trial was then carried out on a subset of biocides against L. monocytogenes on concrete floors in a mushroom growing room and it was found that biocide efficacy in lab-scale did not translate well in pilot-scale.<br><br>CONCLUSIONS: Biocides that are used in the mushroom industry and potential alternative biocides were determined to be effective against L. monocytogenes biofilm in both lab-scale and pilot-scale experiments.<br><br>This study has direct impact for the industry as it provides information on the efficacy of currently used biocides and other biocidal products against L. monocytogenes, an added benefit to their primary use.},
}
@article {pmid32350287,
year = {2020},
author = {Ramos-Vivas, J and Chapartegui-González, I and Fernández-Martínez, M and González-Rico, C and Fortún, J and Escudero, R and Marco, F and Linares, L and Montejo, M and Aranzamendi, M and Muñoz, P and Valerio, M and Aguado, JM and Resino, E and Ahufinger, IG and Vega, AP and Martínez-Martínez, L and Fariñas, MC and , },
title = {Author Correction: Biofilm formation by multidrug resistant Enterobacteriaceae strains isolated from solid organ transplant recipients.},
journal = {Scientific reports},
volume = {10},
number = {1},
pages = {7452},
doi = {10.1038/s41598-020-60496-3},
pmid = {32350287},
issn = {2045-2322},
abstract = {An amendment to this paper has been published and can be accessed via a link at the top of the paper.},
}
@article {pmid32350164,
year = {2020},
author = {Inaba, T and Obana, N and Habe, H and Nomura, N},
title = {Biofilm Formation by Streptococcus mutans is Enhanced by Indole via the Quorum Sensing Pathway.},
journal = {Microbes and environments},
volume = {35},
number = {2},
pages = {},
pmid = {32350164},
issn = {1347-4405},
abstract = {Interspecies interactions among oral microorganisms in the pathogenic biofilms causing dental caries have not yet been elucidated in detail. We herein demonstrated that indole and its derivatives induced biofilm formation by Streptococcus mutans. Indole is an intercellular signaling molecule that is produced by oral bacteria other than S. mutans. The amounts of biofilm and extracellular DNA were significantly increased by the addition of indole and 4-hydroxyindole (4-HI). An examination with quorum sensing mutants showed that the induction of biofilm formation by indole and 4-HI required a quorum sensing system. These results suggest that this intercellular signaling molecule plays a role in pathogenic biofilm formation.},
}
@article {pmid32349419,
year = {2020},
author = {Dong, J and Zhang, L and Liu, Y and Xu, N and Zhou, S and Yang, Q and Yang, Y and Ai, X},
title = {Thymol Protects Channel Catfish from Aeromonas hydrophila Infection by Inhibiting Aerolysin Expression and Biofilm Formation.},
journal = {Microorganisms},
volume = {8},
number = {5},
pages = {},
pmid = {32349419},
issn = {2076-2607},
support = {2019YFD0901702, 2019YFD0900104//National Key R&amp;D Program of China/ ; 31702368//the National Nature Science Foundation of China/ ; },
abstract = {Aeromonas hydrophila is an opportunistic pathogen responsible for a number of diseases in freshwater farming. Moreover, the bacterium has been identified as a zoonotic pathogen that threatens human health. Antibiotics are widely used for treatments of infectious diseases in aquaculture. However, the abuse of antibiotics has led to the emergence of antimicrobial resistant strains. Thus, novel strategies are required against resistant A. hydrophila strains. The quorum sensing (QS) system, involved in virulence factor production and biofilm formation, is a promising target in identifying novel drugs against A. hydrophila infections. In this study, we found that thymol, at sub-inhibitory concentrations, could significantly reduce the production of aerolysin and biofilm formation by inhibiting the transcription of genes aerA, ahyI, and ahyR. These results indicate that thymol inhibits the quorum sensing system. The protective effects of thymol against A. hydrophila mediated cell injury were determined by live/dead assay and lactate dehydrogenase (LDH) release assay. Moreover, the in vivo study showed that thymol could significantly decrease the mortality of channel catfish infected with A. hydrophila. Taken together, these findings demonstrate that thymol could be chosen as a phytotherapeutic candidate for inhibiting quorum sensing system-mediated aerolysin production and biofilm formation in A. hydrophila.},
}
@article {pmid32348684,
year = {2020},
author = {Saleh, D and Sharma, M and Seguin, P and Jabaji, S},
title = {Organic acids and root exudates of Brachypodium distachyon: effects on chemotaxis and biofilm formation of endophytic bacteria.},
journal = {Canadian journal of microbiology},
volume = {},
number = {},
pages = {1-14},
doi = {10.1139/cjm-2020-0041},
pmid = {32348684},
issn = {1480-3275},
abstract = {Root colonization by plant-growth-promoting bacteria could not be useful without the beneficial properties of the bacterium itself. Thus, it is necessary to evaluate the bacterial capacity to form biofilms and establish a successful interaction with the plant roots. We assessed the ability of growth-promoting bacterial strains to form biofilm and display chemotactic behaviour in response to organic acids and (or) root exudates of the model plant Brachypodium distachyon. This assessment was based on the evaluation of single strains of bacteria and a multispecies consortium. The strains coexisted together and formed biofilm under biotic (living root) and abiotic (glass) surfaces. Citric acid stimulated biofilm formation in all individual strains, indicating a strong chemotactic behaviour towards organic acids. Recognizing that the transition from single strains of bacteria to a &quot;multicellular&quot; system would not happen without the presence of adhesion, the alginate and exopolysaccharide (EPS) contents were evaluated. The EPS amounts were comparable in single strains and consortium forms. Alginate production increased 160% in the consortium subjected to drought stress (10% PEG). These findings demonstrated that (i) bacteria-bacteria interaction is the hub of various factors that would not only affect their relation but also could indirectly affect the balanced plant-microbe relation and (ii) root exudates could be very selective in recruiting a highly qualified multispecies consortium.},
}
@article {pmid32348624,
year = {2020},
author = {Mensi, M and Scotti, E and Sordillo, A and Agosti, R and Calza, S},
title = {Plaque disclosing agent as a guide for professional biofilm removal: A randomized controlled clinical trial.},
journal = {International journal of dental hygiene},
volume = {},
number = {},
pages = {},
doi = {10.1111/idh.12442},
pmid = {32348624},
issn = {1601-5037},
abstract = {OBJECTIVES: To evaluate through computer software analysis, the efficacy of the use of a plaque disclosing agent as a visual guide for biofilm removal during professional mechanical plaque removal in terms of post-treatment residual plaque area (RPA).<br><br>METHODS: Thirty-two healthy patients were selected and randomized in two groups to receive a session of professional mechanical plaque removal with air-polishing followed by ultrasonic instrumentation with (Guided Biofilm therapy-GBT) or without (Control) the preliminary application of a plaque disclosing agent as visual guide. The residual plaque area (RPA) was evaluated through re-application of the disclosing agent and computer software analysis, considering the overall tooth surface and the gingival and coronal portions separately.<br><br>RESULTS: A statistically and clinically significant difference between treatments is observed, with GBT achieving an RPA of 6.1% (4.1-9.1) vs 12.0% (8.2-17.3) of the Control on the Gingival surface and of 3.5% (2.3-5.2) vs 9.0% (6-13.1) on the Coronal, with a proportional reduction going from 49.2% (P-value = .018) on the former surface to more than 60% (P-value = .002) on the latter.<br><br>CONCLUSION: The application of a plaque disclosing agent to guide plaque removal seems to lead to better biofilm removal.},
}
@article {pmid32347873,
year = {2020},
author = {He, X and Wu, X and Qiao, Y and Hu, T and Wang, D and Han, X and Li, CM},
title = {Electrical tension-triggered conversion of anaerobic to aerobic respiration of Shewanella putrefaciens CN32 cells while promoting biofilm growth in microbial fuel cells.},
journal = {Chemical communications (Cambridge, England)},
volume = {56},
number = {45},
pages = {6050-6053},
doi = {10.1039/d0cc01605e},
pmid = {32347873},
issn = {1364-548X},
abstract = {A global gene expression analysis of Shewanella putrefaciens CN32 cells nearby a nanostructured microbial anode reveals an electrical tension-triggered conversion of anaerobic respiration to aerobic respiration with increased excretion of flavin electron shuttles and cytochrome C proteins, which sheds light on the role of electric tension in cell organisms.},
}
@article {pmid32346560,
year = {2020},
author = {Razali, MH and Ismail, NA and Amin, KAM},
title = {Physical, mechanical, chemical and biological properties data of gellan gum incorporating titanium dioxide nanoparticles biofilm.},
journal = {Data in brief},
volume = {30},
number = {},
pages = {105478},
pmid = {32346560},
issn = {2352-3409},
abstract = {Gellan gum incorporating titanium dioxide nanoparticles biofilm was synthesized and characterized using UV, FTIR and XRD to study their physical and chemical properties. The mechanical properties were measured using universal mechanical testing. Meanwhile, the biological properties were investigated towards for antibacterial and cell proliferation. This comprehensive data are relevant with the research article entitled &quot;Gellan gum incorporating titanium dioxide nanoparticles biofilm as wound dressing: Physicochemical, mechanical, antibacterial properties and wound healing studies&quot; [1].},
}
@article {pmid32344238,
year = {2020},
author = {Zhao, Y and Shu, X and Tu, Q and Yang, Y and Liu, C and Fu, D and Li, W and Duan, C},
title = {Pollutant removal from agricultural drainage water using a novel double-layer ditch with biofilm carriers.},
journal = {Bioresource technology},
volume = {310},
number = {},
pages = {123344},
doi = {10.1016/j.biortech.2020.123344},
pmid = {32344238},
issn = {1873-2976},
mesh = {Agriculture ; Biofilms ; *Environmental Pollutants ; Nitrogen ; Phosphorus ; *Water ; },
abstract = {Agricultural drainage ditches can prevent flooding and mitigate agricultural pollution; however, the performance is unsatisfactory in plateau areas like the Dianchi Lake basin. Thus, a novel double-layer ditch system (DDS) with a fibrous packing as biofilm carriers was developed to form the carrier-attached biofilms and enhance the pollutant removal. The results indicated the DDS performed better than a single-layer ditch system, and annual average removal efficiencies of TN, NO3--N, NH4+-N, TP, COD and SS were 18.61%, 17.13%, 7.74%, 11.90%, 11.95% and 23.71%, respectively. High amount and carbon, nitrogen and phosphorus contents of biofilms are favourable to pollutant removal by DDS. Although bacterial diversity of biofilms remained relatively stable throughout the year, the relative abundance of dominant assemblages varied greatly. Denitrifying microorganisms affiliated with Bacteroidetes might contribute to effective NO3--N reduction. This study demonstrates DDS performed well and provides a novel method for application of biofilm carriers in drainage ditches.},
}
@article {pmid32342070,
year = {2020},
author = {Jewell, MP and Saccomano, SC and David, AA and Harris, JK and Zemanick, ET and Cash, KJ},
title = {Nanodiagnostics to monitor biofilm oxygen metabolism for antibiotic susceptibility testing.},
journal = {The Analyst},
volume = {145},
number = {11},
pages = {3996-4003},
doi = {10.1039/d0an00479k},
pmid = {32342070},
issn = {1364-5528},
abstract = {In clinical environments, many serious antibiotic-resistant infections are caused by biofilm-forming species. This presents issues when attempting to determine antimicrobial dosing as traditional antibiotic susceptibility tests (ASTs) are typically designed around planktonic bacteria and thus offer information that is not relevant to the biofilm phenotype present in the patient. Even the popular Calgary biofilm device may provide inaccurate minimum biofilm inhibitory concentrations (MBICs) and can be time- and material-intensive. In this work, we present a method utilizing oxygen-sensitive nanosensor technology to monitor the oxygen consumption dynamics of living biofilms as they are exposed to antibiotics. We incorporated our nanosensors into biofilms grown from P. aeruginosa strains of varying sensitivity to traditional classes of antibiotics. Through measuring nanosensor response under antibiotic administration we determined the concentrations able to cease biofilm metabolism. This method provides information on the MBIC as well as kinetic response information in a manner that requires fewer materials and is more reflective of biofilm behavior than a traditional AST.},
}
@article {pmid32341917,
year = {2020},
author = {Metcalf, DG and Bowler, PG},
title = {Clinical impact of an anti-biofilm Hydrofiber dressing in hard-to-heal wounds previously managed with traditional antimicrobial products and systemic antibiotics.},
journal = {Burns &amp; trauma},
volume = {8},
number = {},
pages = {tkaa004},
pmid = {32341917},
issn = {2321-3868},
abstract = {Background: Hard-to-heal wounds are often compromised by the presence of biofilm. This presents an infection risk, yet traditional antimicrobial wound care products and systemic antibiotics are often used despite the uncertainty of therapeutic success and wound progression. The aim of this study was to investigate the clinical impact of a next-generation anti-biofilm Hydrofiber wound dressing (AQUACEL Ag+ Extra[AQAg+ E]) in hard-to-heal wounds that had previously been treated unsuccessfully with traditional silver-, iodine- or polyhexamethylene biguanide (PHMB)-containing dressings and products and/or systemic antibiotics.<br><br>Methods: Clinical case study evaluations of the anti-biofilm dressing were conducted, where deteriorating or stagnant wounds were selected by clinicians and primary dressings were replaced by the anti-biofilm dressing for up to 4 weeks, or as deemed clinically appropriate, with monitoring via case report forms. The data was stratified for cases where traditional silver-, iodine- or PHMB-containing products, or systemic antibiotics, had been used prior to the introduction of the anti-biofilm dressing.<br><br>Results: Sixty-five cases were identified for inclusion, wounds ranging in duration from 1 week to 20 years (median: 12 months). In 47 (72%) cases the wounds were stagnant, while 15 (23%) were deteriorating; 3 wounds were not recorded. After an average of 4.2 weeks of management with the anti-biofilm dressing (range: 1-11 weeks), in 11 (17%) cases the wounds had healed (i.e. complete wound closure), 40 (62%) wounds improved, 9 (14%) wounds remained the same and 5 (8%) wounds deteriorated.<br><br>Conclusions: The introduction of this anti-biofilm dressing into protocols of care that had previously involved wound management with traditional antimicrobial products and/or antibiotics was shown to facilitate improvements in the healing status of most of these hard-to-heal wounds. Dressings containing proven anti-biofilm technology, in combination with antimicrobial silver and exudate management technology, appear to be an effective alternative to traditional antimicrobial products and antibiotics in the cases presented here. The use of antimicrobial wound dressings that contain anti-biofilm technology may have a key role to play in more effective wound management and antibiotic stewardship.},
}
@article {pmid32339889,
year = {2020},
author = {Elmaadawy, K and Hu, J and Guo, S and Hou, H and Xu, J and Wang, D and Liang, T and Yang, J and Liang, S and Xiao, K and Liu, B},
title = {Enhanced treatment of landfill leachate with cathodic algal biofilm and oxygen-consuming unit in a hybrid microbial fuel cell system.},
journal = {Bioresource technology},
volume = {310},
number = {},
pages = {123420},
doi = {10.1016/j.biortech.2020.123420},
pmid = {32339889},
issn = {1873-2976},
mesh = {*Bioelectric Energy Sources ; Biofilms ; Electrodes ; Oxygen ; *Water Pollutants, Chemical ; },
abstract = {An innovative cathodic algal biofilm microbial fuel cell equipped with a bioactive oxygen consuming unit (AB-OCU-MFC) was proposed for enhancing the leachate treatment containing biorefractory organic matters and high strength of ammonium nitrogen. The proposed AB-OCU-MFC performed better with regard to COD, NH4+-N, TN removals and algal biomass yield than standalone algal biofilm-MFC and control reactors. AB-OCU-MFC with OCU of 2 cm thickness removed more than 86% of COD, 89.4% of NH4+-N, 76.7% of TN and produced a maximum voltage of 0.39 V and biomass productivity of 1.23 g·L-1·d-1. The High-throughput sequencing of DNA showed a significant change in microbial community of reactors implemented with OCU, in which the ratio of exoelectrogenic bacteria of anode and denitrifying bacteria on cathode were significantly increased. The results obtained by cathodic algal biofilm MFC with low cost and bioactive barrier of OCU, would provide a new sight for practical application of MFC.},
}
@article {pmid32339850,
year = {2020},
author = {Chotinantakul, K and Chansiw, N and Okada, S},
title = {Biofilm formation and transfer of a streptomycin resistance gene in enterococci from fermented pork.},
journal = {Journal of global antimicrobial resistance},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jgar.2020.04.016},
pmid = {32339850},
issn = {2213-7173},
abstract = {OBJECTIVES: Multidrug-resistant (MDR) enterococci were found extensively in the food samples. This study characterized the phenotypic virulence factors and the ability of horizontal gene transfer of a streptomycin resistance gene among enterococci isolated from fermented pork.<br><br>METHODS: Thirty-six MDR enterococci were subjected to screening of gelatinase, biofilm formation at various temperatures (4, 25 and 37 °C), clumping ability and conjugation.<br><br>RESULTS: All positive-gelatinase and positive-clumping strains wereEnterococcus faecalis (41.7% and 38.9%, respectively). None of E. faecium and E. hirae demonstrated both phenotypes. Moderate and strong biofilm formations were found mostly at optimal temperature in all three species tested. However, moderate and weak biofilm formations could be found in 52.8% at 4 °C. The association between biofilm formation with asa1, efaA, gelE and esp genes was not observed. Surprisingly, our data revealed evidence of the streptomycin resistance gene (aadE) being transferred among meat E. faecalis isolates as characterized by the pheromone-clumping response.<br><br>CONCLUSIONS: Here we report the co-existence of some virulence factors and MDR enterococci from fermented pork. Our data demonstrated for the first time that theaadE gene could be transferred via conjugation among enterococci isolated from meat, contributing to streptomycin resistance. This study highlights the importance of horizontal gene transfer within the food chain reservoir and it might be possible for this to transfer to human, causing harm or untreated diseases.},
}
@article {pmid32339263,
year = {2020},
author = {Ben-Sahil, A and Mohamed, A and Beyenal, H},
title = {Three-dimensional biofilm image reconstruction for assessing structural parameters.},
journal = {Biotechnology and bioengineering},
volume = {},
number = {},
pages = {},
doi = {10.1002/bit.27363},
pmid = {32339263},
issn = {1097-0290},
support = {1706889//National Science Foundation (NSF)/ ; },
abstract = {Parameters representing three-dimensional (3D) biofilm structure are quantified from confocal laser-scanning microscope (CLSM) images. These 3D parameters describe the distribution of biomass pixels within the space occupied by a biofilm; however, they lack a direct connection to biofilm activity. As a result, researchers choose a handful of parameters without there being a consensus on a standard set of parameters. We hypothesized that a select 3D parameter set could be used to reconstruct a biofilm image and that the reconstructed and original biofilm images would have similar activities. To test this hypothesis, an algorithm was developed to reconstruct a biofilm image with parameters identical to those of the original CLSM image. We introduced an objective method to assess the reconstruction algorithm by comparing the activities of the original and reconstructed biofilm images. We found that biofilm images with identical structural parameters showed nearly identical activities and substrate concentration profiles. This implies that the set containing all common structural parameters can successfully describe biofilm structure. This finding is significant, as it opens the door to the next step, of finding a smaller standard set of biofilm structural parameters that can be used to compare biofilm structure.},
}
@article {pmid32338055,
year = {2020},
author = {Delpech, G and Ceci, M and Lissarrague, S and García Allende, L and Baldaccini, B and Sparo, M},
title = {In vitro activity of the antimicrobial peptide AP7121 against the human methicillin-resistant biofilm producers Staphylococcus aureus and Staphylococcus epidermidis.},
journal = {Biofouling},
volume = {36},
number = {3},
pages = {266-275},
doi = {10.1080/08927014.2020.1756266},
pmid = {32338055},
issn = {1029-2454},
abstract = {In vitro activity against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis biofilm producers from blood cultures of patients with prosthetic hip infections was evaluated. The Minimum Inhibitory Concentration (MIC) for AP7121 was determined and the bactericidal activity of AP7121 (MICx1, MICx4) against planktonic cells was studied at 4, 8 and 24 h. The biofilms formed were incubated with AP7121 (MICx1, MICx4) for 1 and 24 h. The anti-adhesion effect of an AP7121-treated inert surface over the highest MIC isolate was studied with scanning electron microscopy (SEM). The bactericidal activity of AP7121 against all the planktonic staphylococcal cells was observed at 4 h at both peptide concentrations. Dose-dependent anti-biofilm activity was detected. AP7121 (MICx4) showed bactericidal activity at 24 h in all isolates. SEM confirmed prevention of biofilm formation. This research showed the in vitro anti-biofilm activity of AP7121 against MRSA and S. epidermidis and the prevention of biofilm formation by them on an abiotic surface.},
}
@article {pmid32335654,
year = {2019},
author = {Sharma, M and Sapkota, J and Jha, B and Mishra, B and Bhatt, CP},
title = {Biofilm Formation and Extended-Spectrum Beta-Lactamase Producer among Acinetobacter Species Isolated in a Tertiary Care Hospital: A Descriptive Cross-sectional Study.},
journal = {JNMA; journal of the Nepal Medical Association},
volume = {57},
number = {220},
pages = {424-428},
pmid = {32335654},
issn = {1815-672X},
abstract = {INTRODUCTION: Acinetobacter species are short, stout, gram-negative coccobacilli, generally considered to be a relatively low-grade pathogen. However, its resistance towards multiple classes of antibiotics through an array of resistance mechanisms including its ability to form biofilm has led to its emergence as an important pathogen in hospital settings. This study was done to determine the prevalence of biofilm former and Extended-spectrum Beta-Lactamase producer among Acinetobacter species.<br><br>METHODS: A descriptive cross-sectional study was done in the clinical microbiology laboratory, Kathmandu Medical College from January to June 2019. Convenient sampling method was used. Ethical approval was taken from the Institutional Review Committee, Ref no. 2812201805. Preliminary identification followed by characterization of Acinetobacter species was done. Antibiotic susceptibility test was done using the Kirby-Bauer method following Clinical and Laboratory Standards Institute guidelines. Extended-spectrum Beta-Lactamase was detected by combined disc method and Biofilm detection was done using congo red agar method. Statistical Package for Social Sciences 16.0 version statistical software package was used for statistical analysis. Point estimate at 95% Confidence Interval was calculated along with frequencyand proportion for binarydata.<br><br>RESULTS: Among 108 Acinetobacter species, 86 (79.7%) Acinetobacter calcoaceticus-A. baumannii complex was seen. Seventy-eight (72%) of the isolates were multidrug-resistant, 34 (31%) of the isolates were Extended-spectrum Beta-Lactamase producer and only 10 (9.3%) of the isolates, were biofilm producers.<br><br>CONCLUSIONS: Multidrug-resistant Acinetobacter spp. with the ability to produce Extended-spectrum Beta-Lactamase is prevalent in our hospital settings. Strict compliance with infection control practices is necessary to curb its spread.},
}
@article {pmid32335283,
year = {2020},
author = {Zheng, M and Shi, J and Xu, C and Han, Y and Zhang, Z and Han, H},
title = {Insights into electroactive biofilms for enhanced phenolic degradation of coal pyrolysis wastewater (CPW) by magnetic activated coke (MAC): Metagenomic analysis in attached biofilm and suspended sludge.},
journal = {Journal of hazardous materials},
volume = {395},
number = {},
pages = {122688},
doi = {10.1016/j.jhazmat.2020.122688},
pmid = {32335283},
issn = {1873-3336},
abstract = {To investigate the role of electroactive biofilms for enhanced phenolic degradation, lignite activated coke (LAC) and MAC were used as carriers in moving-bed biofilm reactor (MBBR) for CPW treatment. In contrast to activated sludge (AS) reactor, the carriers improved degradation performance of MBBR. Although two MBBRs exerted similar degradation capacity with over 92% of COD and 93% phenols removal under the highest phenolics concentration (500 mg/L), the effluent of MAC-based MBBR remained higher biodegradability (BOD5/COD = 0.34 vs 0.18) than that of LAC-based MBBR. Metagenomic analysis revealed that electroactive biofilms determined phenolic degradation of MAC-based MBBR. Primarily, Geobacter (17.33%) started Fe redox cycle on biofilms and developed syntrophy with Syntrophorhabdus (6.47%), which fermented phenols into easily biodegradable substrates. Subsequently, Ignavibacterium (3.38% to 2.52%) and Acidovorax (0.46% to 8.83%) conducted biological electricity from electroactive biofilms to suspended sludge. They synergized with dominated genus in suspended sludge, Alicycliphilus (19.56%) that accounted for phenolic oxidation and nitrate reduction. Consequently, the significantly advantage of Geobater and Syntrophorhabdus was the keystone reason for superior biodegradability maintenance of MAC-based MBBR.},
}
@article {pmid32334358,
year = {2020},
author = {Show, KY and Ling, M and Guo, H and Lee, DJ},
title = {Laboratory and full-scale performances of integrated anaerobic granule-aerobic biofilm-activated sludge processes for high strength recalcitrant paint wastewater.},
journal = {Bioresource technology},
volume = {310},
number = {},
pages = {123376},
doi = {10.1016/j.biortech.2020.123376},
pmid = {32334358},
issn = {1873-2976},
mesh = {Anaerobiosis ; Biofilms ; Bioreactors ; Paint ; *Sewage ; Waste Disposal, Fluid ; *Waste Water ; },
abstract = {Sustainable treatment of wastewaters generated from paint production is increasingly posing an environmental concern. Recalcitrant paint wastewaters are mostly treated by energy and cost intensive physicochemical methods like incineration, distillation or advanced oxidation. This paper reported for the first time a case study applying biological treatment processes to properly handle a high-strength recalcitrant paint wastewater with 5-day biochemical oxygen demand (BOD5)/chemical oxygen demand (COD) less than 0.02. A biological treatment scheme integrating anaerobic granular sludge blanket reactor, aerobic carrier biofilm reactor and aerobic activated sludge bioreactor was proposed and examined. Laboratory and full-scale trials demonstrated satisfactory operation with overall COD removal up to 99%. Besides yielding consistent effluent quality conforming to the discharge limits, the full-scale plant gained considerable savings in operating cost over a 5-year operation. With proper microbial adaptation and cultivation, as well as adequate reactor and process designs, the scheme offers a good feasibility for efficient and cost-effective treatment of the high strength and recalcitrant paint wastewater.},
}
@article {pmid32334259,
year = {2020},
author = {Inaba, T and Aoyagi, T and Hori, T and Charfi, A and Suh, C and Lee, JH and Sato, Y and Ogata, A and Aizawa, H and Habe, H},
title = {Clarifying prokaryotic and eukaryotic biofilm microbiomes in anaerobic membrane bioreactor by non-destructive microscopy and high-throughput sequencing.},
journal = {Chemosphere},
volume = {254},
number = {},
pages = {126810},
doi = {10.1016/j.chemosphere.2020.126810},
pmid = {32334259},
issn = {1879-1298},
abstract = {Anaerobic membrane bioreactor (AnMBR) is used for the treatment of organic solid waste. Clogging of filtration membrane pores, called membrane fouling, is one of the most serious issues for the sustainable operation of AnMBR. Although the physical and chemical mechanisms of the membrane fouling have been widely studied, the biological mechanisms are still unclear. The biofilm formation and development on the membrane might cause the membrane fouling. In this study, the prokaryotic and eukaryotic microbiomes of the membrane-attached biofilms in an AnMBR treating a model slurry of organic solid waste were investigated by non-destructive microscopy and high-throughput sequencing of 16S and 18S rRNA genes. The non-destructive visualization indicated that the biofilm was layered with different structures. The lowermost residual fouling layer was mesh-like and composed of filamentous microorganisms, while the upper cake layer was mainly the non-dense and non-cell region. The principal coordinate and phylogenetic analyses of the sequence data showed that the biofilm microbiomes were different from the sludge. The lowermost layer consisted of operational taxonomic units that were related to Leptolinea tardivitalis and Methanosaeta concilii (9.53-10.07% and 1.14-1.64% of the total prokaryotes, respectively) and Geotrichum candidum (30.22-82.31% of the total eukaryotes), all of which exhibited the filamentous morphology. Moreover, the upper layer was inhabited by the presumably cake-degrading bacteria and predatory eukaryotes. The biofilm microbiome features were consistent with the microscope-visualized structure. These results demonstrated that the biofilm structure and microbiome were the layer specific, which provides better understanding of biological mechanisms of membrane fouling in the AnMBR.},
}
@article {pmid32333655,
year = {2020},
author = {Hassan, K and Hamdy, O and Helmy, M and Mostafa, H},
title = {Enhancing treated wastewater effluent characteristics using hybrid biofilm/activated sludge process - a case study.},
journal = {Water science and technology : a journal of the International Association on Water Pollution Research},
volume = {81},
number = {2},
pages = {217-227},
doi = {10.2166/wst.2020.074},
pmid = {32333655},
issn = {0273-1223},
mesh = {Biofilms ; Bioreactors ; *Sewage ; Waste Disposal, Fluid ; *Waste Water ; },
abstract = {This paper documents the results of 12 months of monitoring of an upgraded hybrid moving bed biofilm reactor-conventional activated sludge wastewater treatment plant (MBBR-CAS WWTP). It also targets the assessment of the increment of the hydraulic load on existing treatment units with a zero construction and land cost. The influent flow to the plant was increased from 21,000 m3 d-1 to 30,000 m3 d-1, 40% of the existing CAS reactor volume was used for the MBBR zone with a carrier fill fraction of 47.62% and with Headworks Bio ActiveCell™ 515 used as media; no modifications were made for the primary and secondary tanks. The hybrid reactor showed high removal efficiencies for biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and total suspended solids (TSS), with average effluent values recording 33.00 ± 8.87 mg L-1, 52.90 ± 9.65 mg L-1 and 29.50 ± 6.64 mg L-1 respectively. Nutrient removals in the hybrid modified biological reactor were moderate compared with carbon removal despite the high C/N ratio of 12.33. Findings in this study favor the application of MBBR in the upgrading of existing CAS plants with the plant BOD5 removal efficiency recording an increase of about 5% compared with the plant before upgrade and effluent values well within the legal requirements.},
}
@article {pmid32333442,
year = {2020},
author = {Binns, R and Li, W and Wu, CD and Campbell, S and Knoernschild, K and Yang, B},
title = {Effect of Ultraviolet Radiation on Candida albicans Biofilm on Poly(methylmethacrylate) Resin.},
journal = {Journal of prosthodontics : official journal of the American College of Prosthodontists},
volume = {},
number = {},
pages = {},
doi = {10.1111/jopr.13180},
pmid = {32333442},
issn = {1532-849X},
abstract = {PURPOSE: To investigate the effect of 254nm ultraviolet light on the viability of Candida albicans biofilm on poly(methylmethacrylate).<br><br>METHODS: Poly(methylmethacrylate) specimens (1cm x 1cm x 1mm) were placed in 6-well culture plates. Each well contained 8ml of 104 colony forming units/milliliter of C. albicans ATCC90028 and Sabouraud dextrose broth. Plates were incubated at 37°Celcius for 24hours. Specimens were then divided into 11 groups (n = 4): no treatment control groups, 3.8% sodium perborate immersion for 5 minutes (PP5m) and for 12 hours (PO12h), and 6 groups exposed to ultraviolet light for 5, 15, 30, 60, 120 or 300 seconds separately using UVP XX-15S series lamps. After sonication, cell suspensions were plated, and colony-forming units were counted. The relationship between survival of C. albicans and ultraviolet light irradiation energy exposure was analyzed and compared to the survival of sodium perborate groups. The effect of disinfection treatments and ultraviolet light energy exposure on C. albicans survival was analyzed with ANOVA (alpha = 0.05).<br><br>RESULTS: There was a significant decrease in C. albicans survival with increasing ultraviolet light energy exposure (p = .00001, p<0.05) Survival vs. immersion exposure time analysis of chemical disinfection showed no survival of C. albicans in groups PP5m and PO12h. C. albicans in the UV 300s group with energy of 210mJ/cm2 (71 CFU/ml) showed a statistical difference from that of two chemical immersion groups (PP5m, PO12h = 0 CFU/ml) (p = .00001, p<0.05).<br><br>CONCLUSION: Ultraviolet 254nm irradiation demonstrated a significant inhibition of C. albicans survival on poly(methylmethacrylate) samples. Ultraviolet light exposure of 300 seconds inhibited the survival of C. albicans close to the level of 3.8% sodium perborate treatment. This article is protected by copyright. All rights reserved.},
}
@article {pmid32332820,
year = {2020},
author = {Wang, T and Guo, Z and Shen, Y and Cui, Z and Goodwin, A},
title = {Accumulation mechanism of biofilm under different water shear forces along the networked pipelines in a drip irrigation system.},
journal = {Scientific reports},
volume = {10},
number = {1},
pages = {6960},
pmid = {32332820},
issn = {2045-2322},
support = {51321001//National Natural Science Foundation of China (National Science Foundation of China)/ ; },
abstract = {The behavior of clogging has a close relationship with the biofilm attached on inner surface of the pipeline in a drip irrigation system using reclaimed water. Therefore, inhibiting biofilm growth is the key to completely addressing the clogging problem. Water shear forces play a vital role in the formation, development and detachment of biofilm. In order to find out the accumulation mechanism of biofilm under different water shear forces, this paper considered 8 different shear forces with a range of [0, 0.7]Pa on the inner surface of pipelines in drip irrigation systems using three kinds of reclaimed water. The results indicate that dry weight (DW), phospholipid fatty acids (PLFAs) and extracellular polymeric substance (EPS) of biofilms show a S-type trend, the maximum contents were observed when τ was 0.2 Pa or 0. 35 Pa. Besides, the influence of water shear forces on biofilms is dual. The formation of biofilm is a dynamic stabilization process. When there is a relatively large shear force, it is favorable to the transport and renewal of microorganisms and nutrients. Meantime, the renewal speed of biofilms is also relatively fast. It is easy to form the biofilms with large surface and small thickness due to relatively high possibility of detachment. When the shear force is small, the transport speed of microorganisms and nutrients are limited, and the ability of microorganisms to secrete polysaccharides is reduced, which makes the nutrients needed for microbial growth insufficient and the adhesion between particles is also reduced, resulting in loose, unstable and an easily removed biofilm structure. After a comprehensive consideration of the dual influence, the critical controlling threshold of internal water shear force was obtained as [0, 0.20] ∪ [0.35, +∞] Pa. In addition, the growth model established in this paper can well describe the growth kinetics of attached biofilms, and provide theoretical reference for monitoring the occurrence of bio-clogging process in drip irrigation systems.},
}
@article {pmid32331171,
year = {2020},
author = {Ji, MK and Moon, BK and Kim, HS and Park, C and Oh, GJ and Cho, H and Lim, HP},
title = {Assessment of Inhibition of Biofilm Formation on TiO₂ Nanotubes According to Non-Thermal Plasma Treatment Conditions and the Elapsed Time in the Atmosphere.},
journal = {Journal of nanoscience and nanotechnology},
volume = {20},
number = {9},
pages = {5742-5745},
doi = {10.1166/jnn.2020.17658},
pmid = {32331171},
issn = {1533-4899},
abstract = {Periimplantitis is an inflammation similar to periodontitis, and is caused by biofilms formed on the surface of dental implants. Application of plasma on biomaterials has been reported to decrease the initial adhesion of microorganism by causing chemical changes without changing the surface morphology. The purpose of this study is to evaluate the effect of inhibition of biofilm formation on the elapsed time after plasma treatment. Non thermal plasma generator (PGS-200 Plasma generator, Expantech Co., Korea) was applied to the specimens. The elapsed time in the atmosphere was set to 5 immediately after treatment, after 30 minutes of treatment, after 60 minutes of treatment, after 90 minutes of treatment. Surface property change with the elapsed time in the atmosphere after plasma treatment were confirmed by X-ray photoelectron spectroscopy and contact angle. Inhibition of biofilm formation was evaluated by the fluorescent nucleic acid staining. It was confirmed that the chemical composition and bonding state of the surface changes as the elapsed time in the atmosphere increases after plasma treatment. The adhesion of Porphyromonas gingivalis was the lowest immediately after plasma treatment, and increased again with increasing elapsed time in the atmosphere after plasma treatment. As a result of this study, it was confirmed that elapsed time in the atmosphere is a very important factor for inhibition of biofilm formation.},
}
@article {pmid32330801,
year = {2020},
author = {Ma, J and Wang, K and Gong, H and Yuan, Q and Yang, M and He, C and Shi, C and San, E},
title = {Integrating floc, aggregate and carrier to reap high-quality anammox biofilm.},
journal = {Bioresource technology},
volume = {309},
number = {},
pages = {123325},
doi = {10.1016/j.biortech.2020.123325},
pmid = {32330801},
issn = {1873-2976},
mesh = {Anaerobiosis ; Biofilms ; *Bioreactors ; Chemoautotrophic Growth ; *Nitrogen ; Oxidation-Reduction ; Sewage ; },
abstract = {This work investigated the effects of integration of floc, aggregate and carrier (IFAC) on anammox biofilm quality and development mechanisms. The IFAC system harvested high-quality anammox biofilm with a reduction of 60% in the formation period, an increment of 282.14%~397.26% in mechanical stability, an enhancement of 10.18 ~ 21.56% in ecological stability and an improvement of 9.44%~46.18% in abundance of the phylum Planctomycetes. Aggregates enabled carriers to accumulate initial biomass efficiently and equipped biofilm with additional joint forces. Floc promoted accumulation of terminal biomass, enhanced ecological stability by improving community diversity and raised abundance of the phylum Planctomycetes by assisting anammox consortium settlement. A model of the development procedure of high-quality anammox biofilm was established and a strategy for pre-designing the IFAC system to reap high-quality biofilm was proposed. We expect our findings to provide theoretical guidance for designs and applications of anammox process with excellent stability.},
}
@article {pmid32329182,
year = {2020},
author = {Huang, Q and Zakaria, BS and Zhang, Y and Zhang, L and Liu, Y and Dhar, BR},
title = {A high-rate anaerobic biofilm reactor for biomethane recovery from source-separated blackwater at ambient temperature.},
journal = {Water environment research : a research publication of the Water Environment Federation},
volume = {},
number = {},
pages = {},
doi = {10.1002/wer.1347},
pmid = {32329182},
issn = {1554-7531},
support = {//Natural Sciences and Engineering Research Council of Canada/ ; },
abstract = {Anaerobic bioreactors for source-separated blackwater are mostly operated at low organic loading rates (OLRs) due to low biodegradability and the potential of ammonia inhibition. In this study, an anaerobic biofilm reactor having conductive carbon fibers as the media was investigated for the high-rate treatment of blackwater collected from vacuum toilets. The bioreactor was operated at different OLRs ranged from 0.77 to 3.01 g COD/L-d in four stages for a total operating period of ~ 250 days. With the increase of OLRs, the specific methane production rate increased from 105.3 to 304.6 ml/L-d with high methane content in biogas (75.5%-83%). The maximum methane yield was achieved at hydraulic retention time (HRT) of 15 days. Highest organics and suspended solids removal (80%-83%) were achieved at 20-days HRT, while increased OLRs resulted in diminished removal efficiencies. The state variables, including pH, total ammonia nitrogen, short-chain volatile fatty acids, and soluble chemical oxygen demand, indicated the system had a great capability to withstand the high OLRs. Microbial community analysis revealed that the high performance might be attributed to direct interspecies electron transfer (DIET) facilitated by potentially electroactive bacteria (e.g., Syntrophomonas, Clostridium) and electrotrophic archaea (e.g., Methanosaeta and Methanosarcina species) enriched on the carbon fibers. PRACTITIONER POINTS: An anaerobic biofilm reactor was investigated for biomethane recovery from source-separated blackwater. Conductive carbon fibers were utilized as the media to stimulate enrichment of potentially electroactive methanogenic communities. The bioreactor was operated at ambient temperature for over 250 days. High methane production rate and high-quality biogas were achieved at OLRs ranged from 0.77 to 3.01 g COD/L-d. Microbial community analysis suggested direct interspecies electron transfer (DIET) between specific electroactive bacteria and electrotrophic archaea.},
}
@article {pmid32329166,
year = {2020},
author = {Mikolai, C and Kommerein, N and Ingendoh-Tsakmakidis, A and Winkel, A and Falk, CS and Stiesch, M},
title = {Early host-microbe interaction in a peri-implant oral mucosa-biofilm model.},
journal = {Cellular microbiology},
volume = {},
number = {},
pages = {e13209},
doi = {10.1111/cmi.13209},
pmid = {32329166},
issn = {1462-5822},
support = {STI 184/6-1//Deutsche Forschungsgemeinschaft/ ; 74ZN1574//Niedersächsisches Ministerium für Wissenschaft und Kultur/ ; },
abstract = {The host-microbe relationship is pivotal for oral health as well as for peri-implant diseases. Peri-implant mucosa and commensal biofilm play important roles in the maintenance of host-microbe homeostasis, but little is known about how they interact. We have therefore investigated the early host-microbe interaction between commensal multispecies biofilm (Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, Porphyromonas gingivalis) and organotypic peri-implant mucosa using our three-dimensional model. After 24 hr, biofilms induced weak inflammatory reaction in the peri-implant mucosa by upregulation of five genes related to immune response and increased secretion of IL-6 and CCL20. Biofilm volume was reduced which might be explained by secretion of β-Defensins-1, -2, and CCL20. The specific tissue reaction without intrinsic overreaction might contribute to intact mucosa. Thus, a relationship similar to homeostasis and oral health was established within the first 24 hr. In contrast, the mucosa was damaged and the bacterial distribution was altered after 48 hr. These were accompanied by an enhanced immune response with upregulation of additional inflammatory-related genes and increased cytokine secretion. Thus, the homeostasis-like relationship was disrupted. Such profound knowledge of the host-microbe interaction at the peri-implant site may provide the basis to improve strategies for prevention and therapy of peri-implant diseases.},
}
@article {pmid32326756,
year = {2020},
author = {Kim, MA and Kim, JH and Nam, OH},
title = {Tea extracts differentially inhibit Streptococcus mutans and Streptococcus sobrinus biofilm colonization depending on the steeping temperature.},
journal = {Biofouling},
volume = {36},
number = {3},
pages = {256-265},
doi = {10.1080/08927014.2020.1755429},
pmid = {32326756},
issn = {1029-2454},
abstract = {This study aimed to evaluate the effects of tea extracts on oral biofilm colonization depending on steeping temperature. S. mutans and S. sobrinus were cultured and treated with green or black tea extracts prepared under different steeping conditions. Biofilm formation, glucosyltransferase (GTF) levels, bacterial growth, and acidogenicity were evaluated. Biofilms were also assessed by gas chromatography-mass spectrometry and confocal laser scanning microscopy. All extracts with hot steeping showed higher inhibitory effects on biofilm formation and cell viability and lower GTF levels compared with those with cold steeping (p < 0.05). Hot steeping significantly reduced bacterial growth (p < 0.05) and maintained the pH. Catechins were only identified from hot steeping extracts. Within the limits of this study, extracts with cold steeping showed lower inhibitory effects on oral biofilms. The different effects between steeping extracts may be attributed to the difference in catechins released from tea extracts under the different steep conditions.},
}
@article {pmid32326753,
year = {2020},
author = {Cocco, AR and Cuevas-Suárez, CE and Liu, Y and Lund, RG and Piva, E and Hwang, G},
title = {Anti-biofilm activity of a novel pit and fissure self-adhesive sealant modified with metallic monomers.},
journal = {Biofouling},
volume = {36},
number = {3},
pages = {245-255},
pmid = {32326753},
issn = {1029-2454},
support = {R01 DE027970/DE/NIDCR NIH HHS/United States ; },
abstract = {Dental plaque is a biofilm composed of a complex oral microbial community. The accumulation of plaque in the pit and fissures of dental elements often leads to the development of tooth decay (dental caries). Here, potent anti-biofilm materials were developed by incorporating zinc methacrylates or di-n-butyl-dimethacrylate-tin into the light-curable sealant and their physical, mechanical, and biological properties were evaluated. The data revealed that 5% di-n-butyl-dimethacrylate-tin (SnM 5%) incorporated sealant showed strong anti-biofilm efficacy against various single-species (Streptococcus mutans or Streptococcus oralis or Candida albicans) and S. mutans-C. albicans cross-kingdom dual-species biofilms without either impairing the mechanical properties of the sealant or causing cytotoxicities against mouse fibroblasts. The findings indicate that the incorporation of SnM 5% in the experimental pit and fissure self-adhesive sealant may have the potential to be part of current chemotherapeutic strategies to prevent the formation of cariogenic oral biofilms that cause dental caries.},
}
@article {pmid32326710,
year = {2020},
author = {Vašková, S and Slobodníková, L and Fajtl, D and Blažíčková, S and Botek, R and Melicháčová, V},
title = {Biofilm-producing potential of urinary pathogens isolated from chronic and recurrent urinary tract infections and impact of biofilm on gentamicin and colistin in vitro efficacy.},
journal = {Epidemiologie, mikrobiologie, imunologie : casopis Spolecnosti pro epidemiologii a mikrobiologii Ceske lekarske spolecnosti J.E. Purkyne},
volume = {69},
number = {1},
pages = {3-9},
pmid = {32326710},
issn = {1210-7913},
mesh = {Anti-Bacterial Agents/pharmacology ; *Bacteria/drug effects/isolation &amp; purification ; *Bacterial Physiological Phenomena/drug effects ; *Biofilms/drug effects ; Chronic Disease ; *Colistin/pharmacology ; Gentamicins/pharmacology ; Humans ; In Vitro Techniques ; Microbial Sensitivity Tests ; *Urinary Tract Infections/microbiology ; },
abstract = {AIM: The presented study was to compare in vitro biofilm production by bacterial strains from chronic/recurrent and from acute non-complicated UTIs. The activity of gentamicin and colistin on biofilm form of these strains has also been detected, with goal to predict the gentamicin and colistin therapeutic efficacy in the antimicrobial treatment of patients with a suspected presence of biofilm in urinary tract.<br><br>MATERIAL AND METHODS: The group of 40 bacterial strains repeatedly isolated from patients with chronic or recurrent UTIs was compared with the group of 40 strains from acute UTIs. Both groups contained comparable number of strains of Escherichia coli, Klebsiella spp., Proteus mirabilis and Pseudomonas aeruginosa. Biofilm production was assessed by method in polystyrene microtiter plate. The MIC and MBC values of gentamicin and colistin were detected by broth microdilution assay. The minimal biofilm inhibitory (MBIC) and biofilm eradication concentrations (MBEC) were tested by microdilution method. Non-inactivated biofilm-associated bacteria were detected after overnight incubation in broth medium free of antimicrobials. The statistical analysis of results was performed by Fisher&#39;s exact test and by Student&#39;s t-test.<br><br>RESULTS: Biofilm was produced by 90% strains from chronic UTIs, but only by 52% of strains from acute UTIs (p = 0.0004). In the biofilm producing strains, the MBIC values of gentamicin reached from four to 256 mg/L, the MBIC levels of colistin from two to 64 mg/L. The minimal biofilm eradicating concentrations were even higher: for gentamicin from eight to > 512 mg/L, and for colistin from 32 to > 512 mg/L. The differences between MIC and MBIC/MBEC levels were statistically highly significant (p < 0.0001). Presumably, the therapeutic success of parenterally applied gentamicin or colistin on biofilm-related urinary tract infections would be, without respect to the high concentration of gentamicin or colistin achievable in urine during parenteral application, rather unpredictable. Local intravesical instillation would allow for achieving higher gentamicin and colistin concentrations; however, there is need for interpretation criteria for MBEC values concerning therapy, as well as for clinical studies allowing for application of those values to predict clinical success of therapy.<br><br>CONCLUSIONS: Laboratory detection of biofilm production and evaluation of the MBIC/MBEC values of antimicrobials for strains producing biofilm might be a valuable complement to the microbiologic diagnostics of chronic and recurrent UTIs. It might provide valuable information for more reliable individualised therapy and so decrease the risk of emergence and selection of multiresistant strains during repeated and non-eradicating therapy of chronic and recurrent UTIs.},
}
@article {pmid32326407,
year = {2020},
author = {Nové, M and Kincses, A and Szalontai, B and Rácz, B and Blair, JMA and González-Prádena, A and Benito-Lama, M and Domínguez-Álvarez, E and Spengler, G},
title = {Biofilm Eradication by Symmetrical Selenoesters for Food-Borne Pathogens.},
journal = {Microorganisms},
volume = {8},
number = {4},
pages = {},
pmid = {32326407},
issn = {2076-2607},
support = {SZTE ÁOK-KKA 2018/270-62-2//Faculty of Medicine, University of Szeged/ ; GINOP-2.3.2-15-2016-00038//Hungary/ ; EFOP 3.6.3-VEKOP-16-2017-00009//Hungary/ ; Iniciativas Ropelanas//Zamora, Spain/ ; Asociación Cultural Trevinca//Zamora, Spain/ ; },
abstract = {Infections caused by Salmonella species and Staphylococcus aureus represent major health and food industry problems. Bacteria have developed many strategies to resist the antibacterial activity of antibiotics, leading to multidrug resistance (MDR). The over-expression of drug efflux pumps and the formation of biofilms based on quorum sensing (QS) can contribute the emergence of MDR. For this reason, the development of novel effective compounds to overcome resistance is urgently needed. This study focused on the antibacterial activity of nine symmetrical selenoesters (Se-esters) containing additional functional groups including oxygen esters, ketones, and nitriles against Gram-positive and Gram-negative bacteria. Firstly, the minimum inhibitory concentrations of the compounds were determined. Secondly, the interaction of compounds with reference antibiotics was examined. The efflux pump (EP) inhibitory properties of the compounds were assessed using real-time fluorimetry. Finally, the anti-biofilm and quorum sensing inhibiting effects of selenocompounds were determined. The methylketone and methyloxycarbonyl selenoesters were the more effective antibacterials compared to cyano selenoesters. The methyloxycarbonyl selenoesters (Se-E2 and Se-E3) showed significant biofilm and efflux pump inhibition, and a methyloxycarbonyl selenoester (Se-E1) exerted strong QS inhibiting effect. Based on results selenoesters could be promising compounds to overcome bacterial MDR.},
}
@article {pmid32326022,
year = {2020},
author = {Angell, IL and Bergaust, L and Hanssen, JF and Aasen, EM and Rudi, K},
title = {Ecological Processes Affecting Long-Term Eukaryote and Prokaryote Biofilm Persistence in Nitrogen Removal from Sewage.},
journal = {Genes},
volume = {11},
number = {4},
pages = {},
pmid = {32326022},
issn = {2073-4425},
abstract = {The factors affecting long-term biofilm stability in sewage treatment remain largely unexplored. We therefore analyzed moving bed bioreactors (MBBRs) biofilm composition and function two years apart from four reactors in a nitrogen-removal sewage treatment plant. Multivariate ANOVA revealed a similar prokaryote microbiota composition on biofilm carriers from the same reactors, where reactor explained 84.6% of the variance, and year only explained 1.5%. Eukaryotes showed a less similar composition with reactor explaining 56.8% of the variance and year 9.4%. Downstream effects were also more pronounced for eukaryotes than prokaryotes. For prokaryotes, carbon source emerged as a potential factor for deterministic assembly. In the two reactors with methanol as a carbon source, the bacterial genus Methylotenera dominated, with M. versatilis as the most abundant species. M. versatilis showed large lineage diversity. The lineages mainly differed with respect to potential terminal electron acceptor usage (nitrogen oxides and oxygen). Searches in the Sequence Read Archive (SRA) database indicate a global distribution of the M. versatilis strains, with methane-containing sediments as the main habitat. Taken together, our results support long-term prokaryote biofilm persistence, while eukaryotes were less persistent.},
}
@article {pmid32325685,
year = {2020},
author = {Rodrigues, CF and Černáková, L},
title = {Farnesol and Tyrosol: Secondary Metabolites with a Crucial quorum-sensing Role in Candida Biofilm Development.},
journal = {Genes},
volume = {11},
number = {4},
pages = {},
pmid = {32325685},
issn = {2073-4425},
support = {1/0537/19//Ministerstvo školstva, vedy, výskumu a športu Slovenskej republiky/ ; },
abstract = {When living in biological and interactive communities, microorganisms use quorum-sensing mechanisms for their communication. According to cell density, bacteria and fungi can produce signaling molecules (e.g., secondary metabolites), which participate, for example, in the regulation of gene expression and coordination of collective behavior in their natural niche. The existence of these secondary metabolites plays a main role in competence, colonization of host tissues and surfaces, morphogenesis, and biofilm development. Therefore, for the design of new antibacterials or antifungals and understanding on how these mechanisms occur, to inhibit the secretion of quorum-sensing (e.g., farnesol and tyrosol) molecules leading the progress of microbial infections seems to be an interesting option. In yeasts, farnesol has a main role in the morphological transition, inhibiting hyphae production in a concentration-dependent manner, while tyrosol has a contrary function, stimulating transition from spherical cells to germ tube form. It is beyond doubt that secretion of both molecules by fungi has not been fully described, but specific meaning for their existence has been found. This brief review summarizes the important function of these two compounds as signaling chemicals participating mainly in Candida morphogenesis and regulatory mechanisms.},
}
@article {pmid32325576,
year = {2020},
author = {Tian, Z and Palomo, A and Zhang, H and Luan, X and Liu, R and Awad, M and Smets, BF and Zhang, Y and Yang, M},
title = {Minimum influent concentrations of oxytetracycline, streptomycin and spiramycin in selecting antibiotic resistance in biofilm type wastewater treatment systems.},
journal = {The Science of the total environment},
volume = {720},
number = {},
pages = {137531},
doi = {10.1016/j.scitotenv.2020.137531},
pmid = {32325576},
issn = {1879-1026},
mesh = {Anti-Bacterial Agents ; *Biofilms ; Drug Resistance, Microbial ; Genes, Bacterial ; Oxytetracycline ; Spiramycin ; Streptomycin ; Waste Water ; },
abstract = {It has been demonstrated that antibiotic resistance could be induced and selected under high antibiotic concentrations in biological wastewater treatment systems. However, little is available regarding the minimum concentrations of antibiotics for selecting antibiotic resistance during wastewater treatment. Herein, the minimum influent concentrations of oxytetracycline, streptomycin, and spiramycin in selecting antibiotic resistance in biofilm type wastewater treatment systems were investigated by spiking respective antibiotic into wastewater with an antibiotic dose increasing from 0 to 0.1, 1, 5, 25, 50 mg/L stepwise over a period of 606 days. Significant increase (p < .01) in the total abundance of antibiotic resistance genes was observed for both streptomycin and oxytetracycline at a dose of 0.1 mg/L according to metagenomic sequencing, while the concentration levels leading to significant increases (p < .05) in resistant bacteria ratio were higher: 5 mg/L for streptomycin and 25 mg/L for oxytetracycline. Although resistome abundance increased with the increase of spiramycin dose, neither the corresponding Macrolide-Lincosamide-Streptogramin (MLS) resistance genes nor the resistant bacteria ratio showed perceptible increase. Partial canonical correspondence analysis showed that both bacterial community shift and mobile genetic elements alteration contributed to the enrichment of resistomes under the presence of streptomycin and oxytetracycline. Regarding spiramycin which is mainly targeting on Gram-positive bacteria, the dominance of the intrinsically resisting Gram-negative bacteria in the biofilm microbiota might be responsible for the vague change of MLS resistant determinants under the spiramycin stress. The results demonstrated that it is possible to prevent the development of antibiotic resistance during wastewater treatment by controlling the influent streptomycin and oxytetracyline concentrations below 0.1 mg/L. This work proposed an actionable approach for the management of antibiotic production wastewater.},
}
@article {pmid32325511,
year = {2020},
author = {Reichling, J},
title = {Anti-biofilm and Virulence Factor-Reducing Activities of Essential Oils and Oil Components as a Possible Option for Bacterial Infection Control.},
journal = {Planta medica},
volume = {86},
number = {8},
pages = {520-537},
doi = {10.1055/a-1147-4671},
pmid = {32325511},
issn = {1439-0221},
mesh = {Anti-Bacterial Agents ; Bacteria ; *Bacterial Infections ; Biofilms ; Chromobacterium ; Humans ; *Oils, Volatile ; Pseudomonas aeruginosa ; Quorum Sensing ; Virulence Factors ; },
abstract = {Pathogenic biofilm-associated bacteria that adhere to biological or nonbiological surfaces are a big challenge to the healthcare and food industries. Antibiotics or disinfectants often fail in an attempt to eliminate biofilms from those surfaces. Based on selected experimental research, this review deals with the potential biofilm-inhibiting, virulence factor-reducing, and biofilm-eradicating activities of essential oils and single essential oil compounds using Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Chromobacterium violaceum as model organisms. In addition, for the bacteria reviewed in this overview, different essential oils and essential oil compounds were reported to be able to modulate the expression of genes that are involved in the formation of autoinducer molecules, biofilms, and virulence factors. The anti-quorum sensing activity of some essential oils and single essential oil compounds was demonstrated using the gram-negative bacterium C. violaceum. Reporter strains of this bacterium produce the violet-colored compound violacein whose synthesis is regulated by quorum sensing autoinducer molecules called acylhomeserinlactones. Of great interest was the discovery that enantiomeric monoterpenes affected the quorum sensing regulation system in different ways. While the (+)-enantiomers of carvone, limonene, and borneol increased violacein formation, their (-)-analogues inhibited violacein production.For the successful eradication of biofilms and the bacteria living inside them, it is absolutely necessary that the lipophilic volatile substances can penetrate into the aqueous channels of biofilms. As shown in recent work, hydrophilic nano-delivery systems encapsulating essential oils/essential oil compounds with antibacterial effects may contribute to overcome this problem.},
}
@article {pmid32325482,
year = {2020},
author = {Yaban, B and Kikhney, J and Musci, M and Petrich, A and Schmidt, J and Hajduczenia, M and Schoenrath, F and Falk, V and Moter, A},
title = {Aerococcus urinae - A potent biofilm builder in endocarditis.},
journal = {PloS one},
volume = {15},
number = {4},
pages = {e0231827},
pmid = {32325482},
issn = {1932-6203},
abstract = {The diagnosis of infective endocarditis (IE) remains a challenge. One of the rare bacterial species recently associated with biofilms and negative cultures in infective endocarditis is Aerococcus urinae. Whether the low number of reported cases might be due to lack of awareness and misidentification, mainly as streptococci, is currently being discussed. To verify the relevance and biofilm potential of Aerococcus in endocarditis, we used fluorescence in situ hybridization to visualize the microorganisms within the heart valve tissue. We designed and optimized a specific FISH probe (AURI) for in situ visualization and identification of A. urinae in sections of heart valves from two IE patients whose 16S rRNA gene sequencing had deteced A. urinae. Both patients had a history of urinary tract infections. FISH visualized impressive in vivo grown biofilms in IE, thus confirming the potential of A. urinae as a biofilm pathogen. In both cases, FISH/PCR was the only method to unequivocally identify A. urinae as the only causative pathogen for IE. The specific FISH assay for A. urinae is now available for further application in research and diagnostics. A. urinae should be considered in endocarditis patients with a history of urinary tract infections. These findings support the biofilm potential of A. urinae as a virulence factor and are meant to raise the awareness of this pathogen.},
}
@article {pmid32325345,
year = {2020},
author = {Faille, C and Brauge, T and Leleu, G and Hanin, A and Denis, C and Midelet, G},
title = {Comparison of the performance of the biofilm sampling methods (swab, sponge, contact agar) in the recovery of Listeria monocytogenes populations considering the seafood environment conditions.},
journal = {International journal of food microbiology},
volume = {325},
number = {},
pages = {108626},
doi = {10.1016/j.ijfoodmicro.2020.108626},
pmid = {32325345},
issn = {1879-3460},
abstract = {AIMS: The aim of this study was to evaluate the performance of sampling methods [contact plates, sponges, and swabs] in the recovery of biofilm Listeria monocytogenes populations considering the seafood environment conditions (nature of conditioning, of materials and bacterial species).<br><br>METHODS AND RESULTS: Different materials (stainless steel, polyvinyl chloride, polyurethane) were conditioned with two fish filtrates, the ready-to-eat the most consumed in Europe (smoked salmon, cod). After, we added the suspension of Listeria monocytogenes, alone or with Pseudomonas fluorescens or Carnobacterium strains, and incubated for 48 h at 8 °C. Then, the 48 h-biofilms were sampled with different methods (contact plates, sponges, and swabs). The cultivable bacterial populations were enumerated on agar, while the L. monocytogenes total and viable populations were quantified by qPCR and propidium monoazide-qPCR (PMA-qPCR), respectively. The amount of L. monocytogenes in biofilms was affected only by the nature of the conditioning with lowest adherent bacteria with cod versus with smoked salmon conditioning. Considering the amount of total population, the swab displayed the lowest values versus the sponges and the contact plates. An explanation was that the observations of the swab by microscopy showed the bacteria trapped within it. The recovery of cultivable bacterial populations was not significantly different with the three sampling methods. On the contrary, we showed that the VBNC populations were only detached by two of three methods (contact plates, sponges) while for the dead populations, those were contact plates and swabs.<br><br>CONCLUSIONS: The nature of the conditioning influenced the amount of the bacteria in biofilms. And the performance of the recovery of the bacterial populations (dead, VBNC, cultivable) was dependent on the methods used.<br><br>This study showed that the seafood environmental conditions influenced the biofilm formation and the assessment of the efficiency of cleaning and disinfectant operations could be significantly affected by the used sampling methods.},
}
@article {pmid32325265,
year = {2020},
author = {Dezhurko-Korol, VA and Novozhilova, NE and Makeeva, IM and Arkhipova, AY and Moisenovich, MM and Akhmadishina, LV and Lukashev, AN and Semenov, AM and Leontieva, MR and Byakova, SF},
title = {The influence of centrifugation and inoculation time on the number, distribution, and viability of intratubular bacteria and surface biofilm in deciduous and permanent bovine dentin.},
journal = {Archives of oral biology},
volume = {114},
number = {},
pages = {104716},
doi = {10.1016/j.archoralbio.2020.104716},
pmid = {32325265},
issn = {1879-1506},
abstract = {The present study aimed to assess the influence of centrifugation and inoculation time on the number, distribution, and viability of intratubular bacteria and surface monospecies E. faecalis biofilm.<br><br>MATERIALS AND METHODS: Forty-four semicylindrical specimens cut from primary (n = 22) and permanent (n = 22) bovine teeth were randomly assigned to the experimental groups. Teeth of each type were inoculated with E. faecalis with and without centrifugation for 1 and 14 days. The number, localization, viability of bacteria and depth of their penetration were assessed with bacterial culturing of dentin shavings, scanning electron microscopy (SEM) and confocal laser electron microscopy (CLSM). Three-way ANOVA with post-hoc Tukey test were used to assess the influence of different experimental setups on dentin infection.<br><br>RESULTS: Severe dentin infection was observed in permanent and deciduous teeth after centrifugation and 1-day incubation: bacteria reached the full length of dentinal tubules and colony-forming units were too numerous to count. The volume of green fluorescence didn't differ significantly in permanent teeth compared with deciduous (p = 1.0). After 1-day stationary inoculation, small number of cultivable bacteria and few viable bacteria in dentinal tubules were found in both groups. After 14-day stationary inoculation, the dentin infection according to CLSM was deeper in deciduous teeth compared with permanent (p = 0.006 and p = 0.019 for centrifugation and stationary inoculation, respectively).<br><br>CONCLUSION: The most even and dense dentin infection was observed in primary and permanent bovine teeth after centrifugation and 1-day inoculation, and in deciduous teeth after 14-day stationary inoculation.},
}
@article {pmid32324227,
year = {2020},
author = {Vaňková, E and Kašparová, P and Dulíčková, N and Čeřovský, V},
title = {Combined effect of lasioglossin LL-III derivative with azoles against Candida albicans virulence factors: biofilm formation, phospholipases, proteases and hemolytic activity.},
journal = {FEMS yeast research},
volume = {20},
number = {3},
pages = {},
doi = {10.1093/femsyr/foaa020},
pmid = {32324227},
issn = {1567-1364},
abstract = {Candida albicans has several virulence factors at its disposal, including yeast-hyphal transition associated with biofilm formation, phospholipases, proteases and hemolytic activity, all of which contribute to its pathogenesis. We used synthetic derivative LL-III/43 of antimicrobial peptide lasioglossin LL-III to enhance effect of azoles on attenuation of C. albicans virulence factors. LL-III/43 was able to inhibit initial adhesion or biofilm formation of C. albicans strains at 50 µM. Azoles, however, were ineffective at this concentration. Using fluorescently labeled LL-III/43, we observed that peptide covered C. albicans cells, partially penetrated through their membranes and then accumulated inside cells. LL-III/43 (25 µM) in combination with clotrimazole prevented biofilm formation already at 3.1 µM clotrimazole. Neither LL-III/43 nor azoles were able to significantly inhibit phospholipases, proteases, or hemolytic activity of C. albicans. LL-III/43 (25 µM) and clotrimazole (50 µM) in combination decreased production of these virulence factors, and it completely attenuated its hemolytic activity. Scanning electron microscopy showed that LL-III/43 (50 µM) prevented C. albicans biofilm formation on Ti-6Al-4 V alloy used in orthopedic surgeries and combination of LL-III/43 (25 µM) with clotrimazole (3.1 µM) prevented biofilm formation on urinary catheters. Therefore, mixture of LL-III/43 and clotrimazole is suitable candidate for future pharmaceutical research.},
}
@article {pmid32322819,
year = {2020},
author = {Permana, AD and Mir, M and Utomo, E and Donnelly, RF},
title = {Bacterially sensitive nanoparticle-based dissolving microneedles of doxycycline for enhanced treatment of bacterial biofilm skin infection: A proof of concept study.},
journal = {International journal of pharmaceutics: X},
volume = {2},
number = {},
pages = {100047},
pmid = {32322819},
issn = {2590-1567},
support = {/WT_/Wellcome Trust/United Kingdom ; },
abstract = {The presence of bacterial biofilms in wounds is a main issue in the healing process. Conventional therapy of bacterial biofilms is hampered by the poor penetration of antibacterial agents through the physical barrier on the infected skin and the non-specific target of antibacterial agents. Here, we present a combination approach of bacterial sensitive nanoparticles (NPs) and dissolving microneedles (MNs) of doxycycline (DOX) for improved biofilm penetration and specifically delivering DOX to the infection site. The NPs were prepared from poly(lactic-co-glycolic acid) and poly (Ɛ-caprolactone) decorated with chitosan. The release of DOX was improved with the presence of bacterial producing biofilm up to 7-fold. The incorporation of these NPs into dissolving MNs was able to significantly enhance the dermatokinetic profiles of DOX, indicated by higher retention time compared to needle-free patches. Importantly, the antibiofilm activity in ex vivo biofilm model showed that after 48 h, the bacterial bioburdens decreased up to 99.99% following the application of this approach. The results presented here assist as proof of principle for the improvement of dermatokinetic profiles and antibiofilm activities of DOX, following its formulation into bacterial sensitive NPs and delivery via MN. Future studies must explore in vivo efficacy in a suitable animal model.},
}
@article {pmid32322380,
year = {2020},
author = {Shayesteh, F and Ahmad, A and Usup, G},
title = {In vitro anti-biofilm activity of bacteriocin from a marine Bacillus sp. strain Sh10 against Proteus mirabilis.},
journal = {Iranian journal of microbiology},
volume = {12},
number = {1},
pages = {52-61},
pmid = {32322380},
issn = {2008-3289},
abstract = {Background and Objectives: Biofilm formed by Proteus mirabilis strains is one of the most important medical problems especially in the case of device-related urinary tract infections. This study was conducted to evaluate the bacteriocin produced by a marine isolate of Bacillus sp. Sh10, for it's in vitro inhibitory activity against pre-formed biofilm and in interference with the biofilm-forming of two biofilm-producing bacteria (P. mirabilis UCa4 and P. mirabilis UCe1).<br><br>Materials and Methods: Sensitivity of two biofilm-producing bacteria (P. mirabilis UCa4 and P. mirabilis UCe1) to bacteriocin, was investigated in planktonic and biofilm states by cell viability and crystal violet assay, respectively. Scanning electron microscopy (SEM) was also performed to determine the effect of bacteriocin on the morphology of the cells associated with biofilm.<br><br>Results: It was found that bacteriocin possessed bactericidal activity to biofilm-forming isolates in the planktonic state. However, bacteriocin interferes with the formation of biofilms and disrupts established biofilms. Bacteriocin reduced biofilm formation in the isolates of P. mirabilis UCa4 and P. mirabilis UCe1 with SMIC50 of 32 and 128 μg/mL, desirable SMIC50 of bacteriocin for biofilm disruption were 128 and 256 μg/mL, respectively. The SEM results indicated that bacteriocin affected the cell morphology of biofilm-associated cells.<br><br>Conclusion: The present findings indicated that bacteriocin from Bacillus sp. Sh10 has bactericidal properties against biofilm-forming isolates of P. mirabilis UCa4 and P. mirabilis UCe1 and has the ability to inhibit the formation of biofilm and disrupt established biofilm.},
}
@article {pmid32321490,
year = {2020},
author = {Kruse, AB and Maamar, R and Akakpo, DL and Woelber, JP and Wittmer, A and Vach, K and Ratka-Krüger, P and Al-Ahmad, A},
title = {Effects of subgingival air-polishing with trehalose powder on oral biofilm during periodontal maintenance therapy: a randomized-controlled pilot study.},
journal = {BMC oral health},
volume = {20},
number = {1},
pages = {123},
pmid = {32321490},
issn = {1472-6831},
support = {ZVS20140127//Duerr Dental SE/ ; },
abstract = {BACKGROUND: This pilot study was part of a larger study which compared the effect of subgingival air-polishing using trehalose powder with sonic scaling on clinical parameters during supportive periodontal therapy. Within this microbiological part of the investigation subgingival samples were taken from 10 participants to analyze the survival of different bacterial species after the two different treatments as a proof of principle.<br><br>METHODS: In 10 participants two non-adjacent, single-root teeth requiring treatment (PD =5 mm with bleeding on probing (BOP) or > 5 mm) were selected following a split-mouth design and were treated either with a sonic scaler or air-polishing device and trehalose powder. For persistent pockets (PD =4 mm and BOP or > 4 mm), treatment was repeated after 3 months. Subgingival biofilm samples were taken at baseline (BL), subsequently and three and six months after treatment. After determination of the bacterial counts (TBL), isolated bacteria were identified by MALDI-TOF-MS. If unsuccessful, PCR and 16S rDNA sequencing were performed.<br><br>RESULTS: In both treatment groups, TBL decreased immediately after treatment remaining at a lower level. This confirms the findings of the larger study regarding clinical parameters showing a comparable effect on PD, BOP and CAL. Immediately after treatment, the diversity of detected species decreased significantly more than in the sonic group (p = 0.03). After 3 months, the proportion of Gram-positive anaerobic rods was lower in the air-polishing group (powder/ sonic 7%/ 25.9%, p = 0.025). Also, there was a greater reduction of Gram-negative aerobic rods for this group at this time (air-polishing/ sonic - 0.91 / -0.23 Log10 cfu/ ml, p = 0.020).<br><br>CONCLUSION: Within the limitations of this study air-polishing and sonic treatment seem to have a comparable effect on the subgingival oral biofilm during supportive periodontal treatment.<br><br>TRIAL REGISTRATION: The study was registered in an international trial register (German Clinical Trial Register number DRKS 00006296) on 10th of June 2015. HTML&amp;TRIAL_ID = DRKS00006296.},
}
@article {pmid32321306,
year = {2020},
author = {Marques, DM and Oliveira, VC and Souza, MT and Zanotto, ED and Issa, JPM and Watanabe, E},
title = {Biomaterials for orthopedics: anti-biofilm activity of a new bioactive glass coating on titanium implants.},
journal = {Biofouling},
volume = {36},
number = {2},
pages = {234-244},
doi = {10.1080/08927014.2020.1755842},
pmid = {32321306},
issn = {1029-2454},
abstract = {This study evaluated adhesion and biofilm formation by Candida albicans, Pseudomonas aeruginosa and Staphylococcus epidermidis on surfaces of titanium (Ti) and titanium coated with F18 Bioactive Glass (BGF18). Biofilms were grown and the areas coated with biofilm were determined after 2, 4 and 8 h. Microscopy techniques were applied in order to visualize the structure of the mature biofilm and the extracellular matrix. On the BGF18 specimens, there was less biofilm formation by C. albicans and S. epidermidis after incubation for 8 h. For P. aeruginosa biofilm, a reduction was observed after incubation for 4 h, and it remained reduced after 8 h on BGF18 specimens. All biofilm matrices seemed to be thicker on BGF18 surface than on titanium surfaces. BGF18 showed significant anti-biofilm activity in comparison with Ti in the initial periods of biofilm formation; however, there was extensive biofilm after incubation for 48 h.},
}
@article {pmid32320601,
year = {2020},
author = {Li, Q and Tan, L and Wang, H and Kou, Y and Shi, X and Zhang, S and Pan, Y},
title = {Fusobacterium nucleatum Interaction with Pseudomonas aeruginosa Induces Biofilm-Associated Antibiotic Tolerance via Fusobacterium Adhesin A.},
journal = {ACS infectious diseases},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsinfecdis.9b00402},
pmid = {32320601},
issn = {2373-8227},
abstract = {Respiratory infections with Pseudomonas aeruginosa or Fusobacterium nucleatum are associated with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and failure in antibiotic treatment. However, the impact of these dual-species interactions on the severity of chronic obstructive pulmonary disease (COPD) and biofilm antibiotic susceptibility remains poorly understood. This study demonstrated that F. nucleatum frequently coexisted with P. aeruginosa in the respiratory tract, and the number of F. nucleatum was negatively correlated with the lung function of AECOPD patients. The coculture of P. aeruginosa and F. nucleatum promoted bacterial proliferation and induced antibiotic tolerance through the formation of a dense biofilm surrounded by excessive Pel and Psl polysaccharides. Moreover, Fusobacterium adhesin A (FadA), rather than F. nucleatum spent medium, induced antibiotic tolerance of the P. aeruginosa biofilm. These results indicate that F. nucleatum is a biomarker of lung function decline in AECOPD patients and interacts with P. aeruginosa in vitro to resist antibiotics via FadA, which would be a potential anti-infective target of these dual-species infection.},
}
@article {pmid32320228,
year = {2020},
author = {Gao, Y and Wang, J and Chai, M and Li, X and Deng, Y and Jin, Q and Ji, J},
title = {Size and Charge Adaptive Clustered Nanoparticles Targeting the Biofilm Microenvironment for Chronic Lung Infection Management.},
journal = {ACS nano},
volume = {14},
number = {5},
pages = {5686-5699},
doi = {10.1021/acsnano.0c00269},
pmid = {32320228},
issn = {1936-086X},
abstract = {Chronic lung infection caused by bacterial biofilms is an extremely serious clinical problem, which can lead to the failure of antibiotic therapy. Although nanoparticles have shown great potential in the treatment of biofilms, the efficient penetration and retention of nanoparticles in biofilms is still a big challenge. To address this issue, we herein fabricate size and charge adaptive azithromycin (AZM)-conjugated clustered nanoparticles (denoted as AZM-DA NPs) as therapeutic agents for treating biofilms. The AZM-DA NPs are prepared by electrostatic complexation between AZM conjugated amino-ended poly(amidoamine) dendrimer (PAMAM) and 2,3-dimethyl maleic anhydride (DA) modified poly(ethylene glycol)-block-polylysine (PEG-b-PLys). It is noteworthy that the AZM-DA NPs can disassemble in an acidic biofilm microenvironment (pH 6.0), leading to the release of secondary AZM-conjugated PAMAM nanoparticles (PAMAM-AZM NPs). PAMAM-AZM NPs with small size and positive charge are beneficial for improved penetration and retention inside biofilms, enhanced permeabilization of the bacterial membrane, and increased internalization of AZM, thus exhibiting excellent antibiofilm activities. AZM-DA NPs are also favorable as long-term antibacterial agents due to the reduced occurrence of drug resistance. In vivo therapeutic performance is confirmed by the reduced bacterial burden and the alleviated inflammation in the chronic lung infection model. This research not only develops an innovative strategy for antibiotic delivery in vivo but also provides an effective way for the management of biofilm-associated infections, including chronic lung infection.},
}
@article {pmid32320095,
year = {2020},
author = {Oda, M and Kurosawa, M and Yamamoto, H and Domon, H and Takenaka, S and Ohsumi, T and Maekawa, T and Yamasaki, N and Furue, Y and Terao, Y},
title = {Sulfated vizantin inhibits biofilm maturation by Streptococcus mutans.},
journal = {Microbiology and immunology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1348-0421.12797},
pmid = {32320095},
issn = {1348-0421},
support = {26293390//Japan Society for the Promotion of Science/ ; 26305034//Japan Society for the Promotion of Science/ ; 26670816//Japan Society for the Promotion of Science/ ; 15H05017//Japan Society for the Promotion of Science/ ; 18H02657//Japan Society for the Promotion of Science/ ; AS2531332Q//Adaptable and Seamless Technology Transfer Program through Target-Driven R and D/ ; //JSPS KAKENHI/ ; },
abstract = {Streptococcus mutans is the main pathogen of dental caries and adheres to the tooth surface via soluble and insoluble glucans produced by the bacterial glucosyltransferase enzyme. Thus, the S. mutans glucosyltransferase is an important virulence factor for this cariogenic bacterium. Sulfated vizantin effectively inhibits biofilm formation by S. mutans without affecting its growth. In this study, less S. mutans biofilm formation occurred on hydroxyapatite discs coated with sulfated vizantin than on noncoated discs. Sulfated vizantin showed no cytotoxicity against the human gingival cell line Ca9-22. Sulfated vizantin dose-dependently inhibited the extracellular release of cell-free glucosyltransferase from S. mutans and enhanced the accumulation of cell-associated glucosyltransferase, compared with that observed with untreated bacteria. Sulfated vizantin disrupted the localization balance between cell-associated glucosyltransferase and cell-free glucosyltransferase, resulting in inhibited biofilm maturation. These results indicate that sulfated vizantin can potentially serve as a novel agent for preventing dental caries.},
}
@article {pmid32318864,
year = {2020},
author = {Iseppi, R and Sabia, C and Bondi, M and Mariani, M and Messi, P},
title = {Virulence Factors, Drug Resistance and Biofilm Formation in Pseudomonas Species Isolated from Healthcare Water Systems.},
journal = {Current microbiology},
volume = {77},
number = {8},
pages = {1737-1745},
doi = {10.1007/s00284-020-01990-9},
pmid = {32318864},
issn = {1432-0991},
abstract = {Pseudomonas aeruginosa is a frequent causative agent of healthcare-associated diseases, but recently, other members of the Pseudomonas genus have been recognized to cause human colonization and infection. Since the aquatic environment could be an important source of contamination, we studied the drug resistance and virulence profiles in Pseudomonas species isolated from healthcare water systems. 17 Pseudomonas spp. out of 57 were randomly selected and their drug resistance and virulence profiles were later evaluated. Based on the positivity to the tests, the adhesion capability and biofilm formation on polystyrene and glass surfaces were studied in 6 strains, each belonging to different species. Six Pseudomonas strains (35%) were α-hemolytic, nine (53%) showed a positivity to the gelatinase test, and P. acidovorans 2R only was capable to degrade DNA. All Pseudomonas strains presented urease activity and the production of siderophores was widely observed (64,7%). Most of the strains showed one of the three types of motilities, 15 Pseudomonas (88.23%) resulted bacteriocin producers and all strains were resistant to one or more antibiotics. Lastly, among the six selected strains, P. aeruginosa 98.5 and P. fluorescens 97.4 were the best biofilm producers. Our study has highlighted how the majority of isolates shows biological characteristics that contribute to the pathogenicity of Pseudomonas. These features emphasize the virulence potentiality of other members of the Pseudomonas genus besides Pseudomonas aeruginosa, making them potentially pathogenic, especially against immunocompromised individuals.},
}
@article {pmid32318110,
year = {2020},
author = {Diriba, K and Kassa, T and Alemu, Y and Bekele, S},
title = {In Vitro Biofilm Formation and Antibiotic Susceptibility Patterns of Bacteria from Suspected External Eye Infected Patients Attending Ophthalmology Clinic, Southwest Ethiopia.},
journal = {International journal of microbiology},
volume = {2020},
number = {},
pages = {8472395},
pmid = {32318110},
issn = {1687-918X},
abstract = {Background: Ocular disease with its complications is a major public health problem which has significant impacts on the quality of life particularly in developing countries. An eye infection due to bacterial agents can lead to reduced vision and blindness. This study was aimed to assess the antimicrobial susceptibility pattern and biofilm-forming potential of bacteria isolated from suspected external eye infected patients in Jimma.<br><br>Method: A cross-sectional facility-based study was conducted on 319 suspect patients with external eye infections from March to June 2017 at Jimma University Medical Center (JUMC) Ophthalmology Department in Ethiopia. External ocular specimens were collected and standard operating procedures were followed to handle and culture throughout the study period. Antimicrobial susceptibility was determined by the disk diffusion method according to CLSI guidelines. Microtiter (96 wells) plate method was used to screen biofilm formation by ELISA reader at 570 nm.<br><br>Results: Out of 319 study participants with an external eye infection, the prevalence of bacterial pathogens was 46.1%. The predominant bacterial isolates were coagulase-negative staphylococcus (CoNS) (27.7%) followed by Staphylococcus aureus (19.7%). Among Gram-negative groups, Pseudomonas aeruginosa (6.8%) was the leading isolate. Increased antimicrobial resistance was observed for tetracycline (64%), erythromycin (66.7%), and penicillin (77.1%). Amoxicillin-clavulanic acid, ciprofloxacin, and gentamicin were the most effective drugs for external eye infections due to susceptibility ranging from 70 to 100% among both Gram-negative and Gram-positive groups. Methicillin-resistant S. aureus (MRSA) accounted for 13.8%. Multidrug resistance (MDR) accounted for 68.7%. The overall biofilm formation rate of bacterial ocular pathogens was 66.1%, where P. aeruginosa (40%), CoNS (34.1%), and S. aureus (31%) formed strong biofilm phenotype.<br><br>Conclusion: The prevalence rate of bacterial isolates was high. Almost all bacterial isolates were resistant to at least one or more drugs. MDR pathogens were observed increasingly among biofilm formers or vice versa.},
}
@article {pmid32316415,
year = {2020},
author = {Sheng, H and Xue, Y and Zhao, W and Hovde, CJ and Minnich, SA},
title = {Escherichia coli O157:H7 Curli Fimbriae Promotes Biofilm Formation, Epithelial Cell Invasion, and Persistence in Cattle.},
journal = {Microorganisms},
volume = {8},
number = {4},
pages = {},
pmid = {32316415},
issn = {2076-2607},
support = {P20GM103408//Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under Grant #P20GM103408/ ; IDAO1467//Agricultural Research Service/ ; IDAO1406//Agricultural Research Service/ ; },
abstract = {Escherichia coli O157:H7 (O157) is noninvasive and a weak biofilm producer; however, a subset of O157 are exceptions. O157 ATCC 43895 forms biofilms and invades epithelial cells. Tn5 mutagenesis identified a mutation responsible for both phenotypes. The insertion mapped within the curli csgB fimbriae locus. Screening of O157 strains for biofilm formation and cell invasion identified a bovine and a clinical isolate with those characteristics. A single base pair A to T transversion, intergenic to the curli divergent operons csgDEFG and csgBAC, was present only in biofilm-producing and invasive strains. Using site-directed mutagenesis, this single base change was introduced into two curli-negative/noninvasive O157 strains and modified strains to form biofilms, produce curli, and gain invasive capability. Transmission electron microscopy (EM) and immuno-EM confirmed curli fibers. EM of bovine epithelial cells (MAC-T) co-cultured with curli-expressing O157 showed intracellular bacteria. The role of curli in O157 persistence in cattle was examined by challenging cattle with curli-positive and -negative O157 and comparing carriage. The duration of bovine colonization with the O157 curli-negative mutant was shorter than its curli-positive isogenic parent. These findings definitively demonstrate that a single base pair stably confers biofilm formation, epithelial cell invasion, and persistence in cattle.},
}
@article {pmid32316222,
year = {2020},
author = {Sampedro, I and Pérez-Mendoza, D and Toral, L and Palacios, E and Arriagada, C and Llamas, I},
title = {Effects of Halophyte Root Exudates and Their Components on Chemotaxis, Biofilm Formation and Colonization of the Halophilic Bacterium Halomonas Anticariensis FP35T.},
journal = {Microorganisms},
volume = {8},
number = {4},
pages = {},
pmid = {32316222},
issn = {2076-2607},
support = {RYC-2014-15532//Ministerio de Economía, Industria y Competitividad, Gobierno de España/ ; },
abstract = {Increase in soil salinity poses an enormous problem for agriculture and highlights the need for sustainable crop production solutions. Plant growth-promoting bacteria can be used to boost the growth of halophytes in saline soils. Salicornia is considered to be a promising salt-accumulating halophyte for capturing large amounts of carbon from the atmosphere. In addition, colonization and chemotaxis could play an important role in Salicornia-microbe interactions. In this study, the role of chemotaxis in the colonization of the halophilic siredophore-producing bacteria, Halomonas anticariensis FP35T, on Salicornia hispanica plants was investigated. The chemotactic response of FP35T to Salicornia root exudates showed optimum dependence at a salt concentration of 5 % NaCl (w/v). Oleanolic acid, the predominant compound in the exudates detected by HPLC and identified by UPLC-HRMS Q-TOF, acts as a chemoattractant. In vitro experiments demonstrated the enhanced positive effects of wild-type H. anticariensis strain FP35T on root length, shoot length, germination and the vigour index of S. hispanica. Furthermore, these positive effects partially depend on an active chemotaxis system, as the chemotaxis mutant H. anticariensis FP35 ΔcheA showed reduced plant growth promotion for all the parameters tested. Overall, our results suggest that chemotaxis responses to root exudates play an important role in interactions between Salicornia and halophilic bacteria, enhance their colonization and boost plant growth promotion. Preliminary results also indicate that root exudates have a positive impact on H. anticariensis FP35T biofilm formation under saline conditions, an effect which totally depends on the presence of the cheA gene.},
}
@article {pmid32315795,
year = {2020},
author = {Chen, Z and Zhang, X and Ma, Y and Song, Y and Li, Y and Geng, G and Huang, Y},
title = {Anammox biofilm system under the stress of Hg(II): Nitrogen removal performance, microbial community dynamic and resistance genes expression.},
journal = {Journal of hazardous materials},
volume = {395},
number = {},
pages = {122665},
doi = {10.1016/j.jhazmat.2020.122665},
pmid = {32315795},
issn = {1873-3336},
abstract = {The existence of heavy metals in wastewater has obtained more attention due to its high toxicity and non-degradability. In this study, we investigated the changes of anaerobic ammonium oxidation (Anammox) system under long-term invasion of Hg(Ⅱ). The results indicated that the total nitrogen removal efficiency (TNRE) dropped to around 55 % as Hg(Ⅱ) concentration went up to 20 mg L-1. But the functional bacteria rapidly developed some resistant abilities and maintained a stable TNRE of 65 % till the end of test. The maximum relative expression fold change of merA, merB, merD and merR were 468.8476, 23.7383, 5.0321 and 15.2514 times, respectively. The high positive correlation between the expression abundance of metal resistance genes and the concentrations of Hg(Ⅱ) revealed the resistant mechanisms of microorganisms to heavy metals. Moreover, the protective strategy based on extracellular polymeric substances also contributed to the stability of Anammox system.},
}
@article {pmid32315688,
year = {2020},
author = {Gumus, B and Acar, T and Atabey, T and Derman, S and Sahin, F and Arasoglu, T},
title = {The battle against biofilm infections: juglone loaded nanoparticles as an anticandidal agent.},
journal = {Journal of biotechnology},
volume = {316},
number = {},
pages = {17-26},
doi = {10.1016/j.jbiotec.2020.04.009},
pmid = {32315688},
issn = {1873-4863},
abstract = {In this study, juglone nanoparticles were prepared by single emulsion solvent evaporation method and their effect against Candida albicans biofilm was investigated in comparison with the free juglone and Fluconazole by performing XTT, crystal violet, standard plate count, confocal microscopy and membrane depolarization analyses. Juglone nanoparticles and free juglone were found to inhibit biofilm formation and pre-established biofilms (98-100%) at all doses tested, whereas Fluconazole did not cause a significant inhibition, even at the highest dose applied, especially against pre-established biofilms. Membrane depolarization analysis showed that free juglone and juglone loaded nanoparticles were effective on C. albicans membrane structure and have fluorescence quenching effect on DiSC3(5). It is extremely important that the antibiofilm activity of the juglone nanoparticles is similar to that of the juglone used at the same concentration, since similar effect is provided by using less active substance due to controlled release. Accordingly, it can easily be said that juglone loaded nanoparticles are much more effective in the formation and elimination of C. albicans biofilm than the free juglone and Fluconazole.},
}
@article {pmid32309695,
year = {2020},
author = {Ahmed, B and Ameen, F and Rizvi, A and Ali, K and Sonbol, H and Zaidi, A and Khan, MS and Musarrat, J},
title = {Destruction of Cell Topography, Morphology, Membrane, Inhibition of Respiration, Biofilm Formation, and Bioactive Molecule Production by Nanoparticles of Ag, ZnO, CuO, TiO2, and Al2O3 toward Beneficial Soil Bacteria.},
journal = {ACS omega},
volume = {5},
number = {14},
pages = {7861-7876},
pmid = {32309695},
issn = {2470-1343},
abstract = {The unregulated discharge of nanoparticles (NPs) from various nanotechnology industries into the environment is expected to alter the composition and physiological functions of soil microbiota. Considering this knowledge gap, the impact of five NPs (Ag, ZnO, CuO, Al2O3, and TiO2) differing in size and morphology on growth behavior and physiological activity of Azotobacter chroococcum, Bacillus thuringiensis, Pseudomonas mosselii, and Sinorhizobium meliloti were investigated. Various biochemical and microscopic approaches were adopted. Interestingly, all bacterial strains were found sensitive to Ag-NPs and ZnO-NPs but showed tolerance toward CuO, Al2O3, and TiO2-NPs. The loss of cellular respiration due to NPs was coupled with a reduction in population size. ZnO-NPs at 387.5 μg mL-1 had a maximum inhibitory impact on A. chroococcum and reduced its population by 72%. Under Ag-NP stress, the reduction in IAA secretion by bacterial strains followed the order S. meliloti (74%) > P. mosselii (63%) > A. chroococcum (49%). The surface of bacterial cells had small- or large-sized aggregates of NPs. Also, numerous gaps, pits, fragmented, and disorganized cell envelopes were visible. Additionally, a treated cell surface appeared corrugated with depressions and alteration in cell length and a strong heterogeneity was noticed under atomic force microscopy (AFM). For instance, NPs induced cell roughness for P. mosselii followed the order 12.6 nm (control) > 58 nm (Ag-NPs) > 41 nm (ZnO-NPs). TEM analysis showed aberrant morphology, cracking, and disruption of the cell envelope with extracellular electron-dense materials. Increased permeability of the inner cell membrane caused cell death and lowered EPS production. Ag-NPs and ZnO-NPs also disrupted the surface adhering ability of bacteria, which varied with time and concentration of NPs. Conclusively, a plausible mechanism of NP toxicity to bacteria has been proposed to understand the mechanistic basis of ecological interaction between NPs and resourceful bacteria. These results also emphasize to develop strategies for the safe disposal of NPs.},
}
@article {pmid32308750,
year = {2020},
author = {Wang, C and Chen, P and Qiao, Y and Kang, Y and Yan, C and Yu, Z and Wang, J and He, X and Wu, H},
title = {pH responsive superporogen combined with PDT based on poly Ce6 ionic liquid grafted on SiO2 for combating MRSA biofilm infection.},
journal = {Theranostics},
volume = {10},
number = {11},
pages = {4795-4808},
pmid = {32308750},
issn = {1838-7640},
abstract = {Background: Biofilm infection caused by multidrug-resistant bacteria is difficult to eradicate by conventional therapies. Photodynamic therapy (PDT) is an effective antibacterial method for fighting against biofilm infection. However, the blocked photosensitizers outside of biofilm greatly limit the efficacy of PDT. Methods: Herein, a novel acid-responsive superporogen and photosensitizer (SiO2-PCe6-IL) was developed. Because of the protonation of the photosensitizer and the high binding energy of the polyionic liquid, SiO2-PCe6-IL changed to positive SiO2-PIL+ in an acidic microenvironment of biofilm infection. SiO2-PIL+ could combine with negatively charged extracellular polymeric substances (EPS) and create holes to remove the biofilm barrier. To strengthen the interaction between SiO2-PIL+ and EPS, SiO2-PIL+ of high charge density was prepared by grafting the high-density initiation site of ATRP onto the surface of the SiO2 base. Results: Due to the rapid protonation rate of COO- and the strong binding energy of SiO2-PIL+ with EPS, SiO2-PCe6-IL could release 90% of Ce6 in 10 s. With the stronger electrostatic and hydrophobic interaction of SiO2-PIL+ with EPS, the surface potential, hydrophobicity, adhesion and mechanical strength of biofilm were changed, and holes in the biofilm were created in 10 min. Combining with the release of photosensitizers and the porous structure of the biofilm, Ce6 was efficiently concentrated in the biofilm. The in vitro and in vivo antibacterial experiments proved that SiO2-PCe6-IL dramatically improved the PDT efficacy against MRSA biofilm infection. Conclusion: These findings suggest that SiO2-PCe6-IL could rapidly increase the concentration of photosensitizer in biofilm and it is an effective therapy for combating biofilm infection.},
}
@article {pmid32307570,
year = {2020},
author = {Shen, C and Islam, MT and Masuda, Y and Honjoh, KI and Miyamoto, T},
title = {Transcriptional changes involved in inhibition of biofilm formation by ε-polylysine in Salmonella Typhimurium.},
journal = {Applied microbiology and biotechnology},
volume = {104},
number = {12},
pages = {5427-5436},
doi = {10.1007/s00253-020-10575-2},
pmid = {32307570},
issn = {1432-0614},
support = {DI-7201//Agriculture, Forestry and Fisheries Research Council/ ; },
abstract = {The pathogenicity of Salmonella Typhimurium, a foodborne pathogen, is mainly attributed to its ability to form biofilm on food contact surfaces. ε-polylysine, a polymer of positively charged lysine, is reported to inhibit biofilm formation of both gram-positive and gram-negative bacteria. To elucidate the mechanism underlying ε-polylysine-mediated inhibition of biofilm formation, the transcriptional profiles of ε-polylysine-treated and untreated Salmonella Typhimurium cells were comparatively analysed. The genome-wide DNA microarray analysis was performed using Salmonella Typhimurium incubated with 0.001% ε-polylysine in 0.1% Bacto Soytone at 30 °C for 2 h. The expression levels of genes involved in curli amyloid fibres and cellulose production, quorum sensing, and flagellar motility were downregulated, whereas those of genes associated with colanic acid synthesis were upregulated after treatment with ε-polylysine. The microarray results were validated by quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, treatment with ε-polylysine decreased the production of colanic acid in Salmonella Typhimurium. The findings of this study improved our understanding of the mechanisms underlying ε-polylysine-mediated biofilm inhibition and may contribute to the development of new disinfectants to control biofilm during food manufacturing and storage.},
}
@article {pmid32307173,
year = {2020},
author = {Elegbeleye, JA and Buys, EM},
title = {Molecular characterization and biofilm formation potential of Bacillus subtilis and Bacillus velezensis in extended shelf-life milk processing line.},
journal = {Journal of dairy science},
volume = {103},
number = {6},
pages = {4991-5002},
doi = {10.3168/jds.2019-17919},
pmid = {32307173},
issn = {1525-3198},
abstract = {This study aims to characterize Bacillus subtilis complex group from raw, pasteurized, and packaged extended shelf-life (ESL) milk samples, to determine their biofilm potential and source-track the microbial contaminants to control their presence during processing. Isolates were characterized using multi-locus sequence typing (MLST) with 7 housekeeping genes. The primers used were designed from the coding regions with the highest number of polymorphic sites. The heat resistance profile indicated that all 12 isolates are psychrotolerant as well as thermophilic, with temperature ranges of 6°C to 55°C (B43, B44, B52, B54, B55, B56, B57), 6°C to 60°C (B46, B47, B48), and 15°C to 60°C (B49, B50). A general linear model 2-way repeated-measure ANOVA of the biofilm-forming potential of the isolates shows a statistically significant difference across the time of incubation (6, 12, 18, and 24 h). All isolates except 2 formed moderate to strong biofilms, with B44 having the most robust biofilm formation (3.14 ± 0.60). Scanning electron and confocal microscopy images reveal the strain specificity of the biofilm structure. The MLST analysis identified all isolates as belonging to either B. subtilis or Bacillus velezensis. All the isolates were novel sequence types (ST) when compared with the PubMLST database (https://pubmlst.org/) but showed relatedness to isolates in the raw milk that was processed. The closest ST are 96 for B. velezensis and 128 for B. subtilis, mostly isolated from soil. This study presents the significance of biofilms of thermophilic B. subtilis and B. velezensis and their possible perpetuation in the dairy processing plant. The information provided is a call for an innovative food contact surface or any other intervention that can minimize or prevent microbial adhesion in the processing plant, to prevent negative effects in ESL milk.},
}
@article {pmid32304794,
year = {2020},
author = {Alvarenga, DJ and Matias, LMF and Oliveira, LM and Leão, LPMO and Hawkes, JA and Raimundo, BVB and Castro, LFD and Campos, MMA and Siqueira, FDS and Santos, TD and Carvalho, DT},
title = {Exploring how structural changes to new Licarin A derivatives effects their bioactive properties against rapid growing mycobacteria and biofilm formation.},
journal = {Microbial pathogenesis},
volume = {144},
number = {},
pages = {104203},
doi = {10.1016/j.micpath.2020.104203},
pmid = {32304794},
issn = {1096-1208},
abstract = {Several species of rapidly growing mycobacteria (RGM) have been associated with biofilms in areas such as biomedical devices, water distribution systems, cosmetic surgery, and catheter-related blood infections. Biofilms which exhibit antimicrobial resistance such as those formed by the genus Mycobacterium pose a significant risk to health and are of particular interest to researchers. Licarin A (a neolignan found in numerous plant species e.g. nutmeg) has been reported to show a wide range of biological actions including anti-inflammatory, antioxidant, and antibacterial properties. The aim of this study was to prepare a set of Licarin A derivatives and investigate the impact of specific structural changes on its antimycobacterial ability, and its effect on the biofilm formation of RGM species. Initially, the phenolic sub-unit and alkenyl side chain of Licarin A were modified to create derivatives with a higher partition coefficient; as the activity of a compound against mycobacteria seems to be strongly influenced by its hydrophobicity. Further, polar groups were inserted into the side chain to change the hydrophilic-lipophilic profile of the molecules. Results showed variability in the susceptibility profile of mycobacteria against the Licarin A derivatives under analysis. A number of the derivatives showed significant inhibitory activity of planktonic growth of the three strains of mycobacteria used, with even lower MIC values than those observed with reference drugs and Licarin A itself. Cytotoxicity assays showed they also have low toxicity, confirming that structural modifications to the Licarin A have made improvements to its antimycobacterial properties.},
}
@article {pmid32303851,
year = {2020},
author = {Grudlewska-Buda, K and Skowron, K and Gospodarek-Komkowska, E},
title = {Comparison of the intensity of biofilm formation by Listeria monocytogenes using classical culture-based method and digital droplet PCR.},
journal = {AMB Express},
volume = {10},
number = {1},
pages = {75},
pmid = {32303851},
issn = {2191-0855},
abstract = {Listeria monocytogenes is a Gram-positive bacterium, commonly found in food, water or sewage. This microorganism is capable of forming biofilm on different surfaces such as steel, glass, polypropylene etc. Recently an increase in cases of listeriosis has been noted, making L. monocytogenes the important health threat. Therefore, there is a need for rapid and sensitive detection of this pathogen. This study aimed to compare the number of L. monocytogenes cells recovered from the biofilm (prepared on steel and polypropylene) using the detection and amplification of the hlyA gene (droplet digital PCR, ddPCR) and the classical culture method. The research material consisted of 96 L. monocytogenes strains. A total of 58 isolates were obtained from clinical samples and 38 isolates derived from the municipal sewage treatment plant. Additionally, the reference strain ATCC®19111™ (WDCM00020) was used. The Pearson correlation coefficient for the results obtained by the classical culture-based method and ddPCR was 0.864 and 0.725, for biofilms produced on AISI 304 stainless steel surface and the polypropylene surface, respectively. Correlations were statistically significant (p ≤ 0.001), indicating that the ddPCR technique is an effective tool for the assessment of bacteria number in the biofilm.},
}
@article {pmid32302854,
year = {2020},
author = {Peng, YY and Gao, F and Yang, HL and Wu, HW and Li, C and Lu, MM and Yang, ZY},
title = {Simultaneous removal of nutrient and sulfonamides from marine aquaculture wastewater by concentrated and attached cultivation of Chlorella vulgaris in an algal biofilm membrane photobioreactor (BF-MPBR).},
journal = {The Science of the total environment},
volume = {725},
number = {},
pages = {138524},
doi = {10.1016/j.scitotenv.2020.138524},
pmid = {32302854},
issn = {1879-1026},
abstract = {Microalgae based wastewater treatment has attracted increasing attention for its many advantages in recent years. In this study, a novel microalgae biofilm membrane photobioreactor (BF-MPBR) was developed for the efficient microalgae cultivation and the removal of nutrient and sulfonamides (SAs) from marine aquaculture wastewater. Two BF-MPBRs with hydraulic retention time (HRT) of 1 day and 2 days respectively were continuously operated for 70 days without harvesting microalgae. Concentrated and attached culture of marine Chlorella vulgaris was achieved in these continuous flow BF-MPBRs due to the suspended solid carriers and microfiltration membrane module in the reactors. The algal biomass productivity achieved in BF-MPBRs with HRT of 1 day and 2 days were 14.02 and 22.03 mg L-1 day-1, respectively. In addition, at the end of the cultivation, 60.4% and 45.0% of microalgae were fixed into algal biofilm in BF-MPBRs with 1 day and 2 day HRT, respectively. Compared with batch cultivation, more efficient nutrient and SAs removal performance was achieved in BF-MPBRs, although the HRT of the BF-MPBRs used in this study was only 1 or 2 days. During the stable operation stage of the BF-MPBRs, the reduction in dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), sulfadiazine (SDZ), sulfamethazine (SMZ) and sulfamethoxazole (SMX) were found in the range of 91.0-99.6%, 92.1-98.4%, 61.0-79.2%, 50.0-76.7% and 60.8-82.1%, respectively. Therefore, nutrient and SAs were simultaneously and efficiently removed from marine aquaculture wastewater by microalgae cultivation in BF-MPBR.},
}
@article {pmid32302361,
year = {2020},
author = {Pestrak, MJ and Gupta, TT and Dusane, DH and Guzior, DV and Staats, A and Harro, J and Horswill, AR and Stoodley, P},
title = {Investigation of synovial fluid induced Staphylococcus aureus aggregate development and its impact on surface attachment and biofilm formation.},
journal = {PloS one},
volume = {15},
number = {4},
pages = {e0231791},
pmid = {32302361},
issn = {1932-6203},
support = {P01 AI083211/AI/NIAID NIH HHS/United States ; R01 GM124436/GM/NIGMS NIH HHS/United States ; },
abstract = {Periprosthetic joint infections (PJIs) are a devastating complication that occurs in 2% of patients following joint replacement. These infections are costly and difficult to treat, often requiring multiple corrective surgeries and prolonged antimicrobial treatments. The Gram-positive bacterium Staphylococcus aureus is one of the most common causes of PJIs, and it is often resistant to a number of commonly used antimicrobials. This tolerance can be partially attributed to the ability of S. aureus to form biofilms. Biofilms associated with the surface of indwelling medical devices have been observed on components removed during chronic infection, however, the development and localization of biofilms during PJIs remains unclear. Prior studies have demonstrated that synovial fluid, in the joint cavity, promotes the development of bacterial aggregates with many biofilm-like properties, including antibiotic resistance. We anticipate these aggregates have an important role in biofilm formation and antibiotic tolerance during PJIs. Therefore, we sought to determine specifically how synovial fluid promotes aggregate formation and the impact of this process on surface attachment. Using flow cytometry and microscopy, we quantified the aggregation of various clinical S. aureus strains following exposure to purified synovial fluid components. We determined that fibrinogen and fibronectin promoted bacterial aggregation, while cell free DNA, serum albumin, and hyaluronic acid had minimal effect. To determine how synovial fluid mediated aggregation affects surface attachment, we utilized microscopy to measure bacterial attachment. Surprisingly, we found that synovial fluid significantly impeded bacterial surface attachment to a variety of materials. We conclude from this study that fibrinogen and fibronectin in synovial fluid have a crucial role in promoting bacterial aggregation and inhibiting surface adhesion during PJI. Collectively, we propose that synovial fluid may have conflicting protective roles for the host by preventing adhesion to surfaces, but by promoting bacterial aggregation is also contributing to the development of antibiotic tolerance.},
}
@article {pmid32299665,
year = {2020},
author = {Vyas, N and Grewal, M and Kuehne, SA and Sammons, RL and Walmsley, AD},
title = {High speed imaging of biofilm removal from a dental implant model using ultrasonic cavitation.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {36},
number = {6},
pages = {733-743},
doi = {10.1016/j.dental.2020.03.003},
pmid = {32299665},
issn = {1879-0097},
abstract = {OBJECTIVES: Current instruments cannot clean in between dental implant threads and effectively remove biofilm from the rough implant surface without damaging it. Cavitation bubbles have the potential to disrupt biofilms. The aim of this study was to see how biofilms can be disrupted using non-contact cavitation from an ultrasonic scaler, imaged inside a restricted implant pocket model using high speed imaging.<br><br>METHODS: Streptococcus sanguinis biofilm was grown for 7 days on dental implants. The implants were placed inside a custom made restricted pocket model and immersed inside a water tank. An ultrasonic scaler tip was placed 0.5mm away from the implant surface and operated at medium power or high power for 2s. The biofilm removal process was imaged using a high speed camera operating at 500 fps. Image analysis was used to calculate the amount of biofilm removed from the high speed images. Scanning electron microscopy was done to visualize the implant surface after cleaning.<br><br>RESULTS: Cavitation was able to remove biofilm from dental implants. More biofilm was removed at high power. Scanning electron microscopy showed that the implant surface was clean at the points where the cavitation was most intense. High speed imaging showed biofilm removal underneath implant threads, in areas next to the ultrasonic scaler tip.<br><br>SIGNIFICANCE: A high speed imaging protocol has been developed to visualize and quantify biofilm removal from dental implants in vitro. Cavitation bubbles from dental ultrasonic scalers are able to successfully disrupt biofilm in between implant threads.},
}
@article {pmid32295873,
year = {2020},
author = {Bailey, MT and Lauber, CL and Novotny, LA and Goodman, SD and Bakaletz, LO},
title = {Immunization with a Biofilm-Disrupting Nontypeable Haemophilus influenzae Vaccine Antigen Did Not Alter the Gut Microbiome in Chinchillas, Unlike Oral Delivery of a Broad-Spectrum Antibiotic Commonly Used for Otitis Media.},
journal = {mSphere},
volume = {5},
number = {2},
pages = {},
pmid = {32295873},
issn = {2379-5042},
support = {R01 DC011818/DC/NIDCD NIH HHS/United States ; },
abstract = {The use of broad-spectrum antibiotics to treat diseases, such as the highly prevalent pediatric disease otitis media (OM), contributes significantly to the worldwide emergence of multiple-antibiotic-resistant microbes, and gut dysbiosis with diarrhea is a common adverse sequela. Moreover, for many diseases, like OM, biofilms contribute significantly to chronicity and recurrence, yet biofilm-resident bacteria are characteristically highly resistant to antibiotics. The most cost-effective way to both prevent and resolve diseases like OM, as well as begin to address the problem of growing antibiotic resistance, would be via the development of novel approaches to eradicate bacterial biofilms. Toward this goal, we designed a vaccine antigen that induces the formation of antibodies that prevent biofilm formation and, thereby, experimental OM in the middle ears of chinchillas by the predominant Gram-negative pathogen responsible for this disease, nontypeable Haemophilus influenzae These antibodies also significantly disrupt preexisting biofilms formed by diverse pathogens. Whereas preclinical data strongly support the continued development of this vaccine antigen, which targets an essential structural element of bacterial biofilms, a concern has been whether active immunization would also lead to unintended collateral damage in the form of an altered gut microbiome. To address this concern, we assessed changes in the microbiome of the chinchilla gut over time after the delivery of either amoxicillin-clavulanate, the standard of care for OM, or after immunization with our biofilm-targeted vaccine antigen either via a traditional subcutaneous route or via a novel noninvasive transcutaneous route. We show that differences in the abundance of specific taxa were found only in the stools of antibiotic-treated animals.IMPORTANCE The prevalence of chronic and recurrent diseases, combined with the overuse/abuse of antibiotics that has led to the sobering emergence of bacteria resistant to multiple antibiotics, has mandated that we develop novel approaches to better manage these diseases or, ideally, prevent them. Biofilms play a key role in the pathogenesis of chronic and recurrent bacterial diseases but are difficult, if not impossible, to eradicate with antibiotics. We developed a vaccine antigen designed to mediate biofilm disruption; however, it is also important that delivery of this vaccine does not induce collateral damage to the microbiome. The studies described here validated a vaccine approach that targets biofilms without the consequences of an altered gut microbiome. While delivery of the antibiotic most commonly given to children with ear infections did indeed alter the gut microbiome, as expected, immunization via traditional injection or by noninvasive delivery to the skin did not result in changes to the chinchilla gut microbiome.},
}
@article {pmid32294591,
year = {2020},
author = {Li, T and Zhou, Q and Zhou, L and Yan, Y and Liao, C and Wan, L and An, J and Li, N and Wang, X},
title = {Acetate limitation selects Geobacter from mixed inoculum and reduces polysaccharide in electroactive biofilm.},
journal = {Water research},
volume = {177},
number = {},
pages = {115776},
doi = {10.1016/j.watres.2020.115776},
pmid = {32294591},
issn = {1879-2448},
mesh = {Acetates ; *Bioelectric Energy Sources ; Biofilms ; Electrodes ; *Geobacter ; Polysaccharides ; },
abstract = {Bioelectrochemical systems (BESs) are widely investigated as a promising technology to recover bioenergy or synthesize value-added products from wastewaters. The performance of BES depends on the activity of electroactive biofilm (EAB). As the core of BES, it is still unclear how the EAB is formed from mixed inoculum, and how exoelectrogens compete with non-exoelectrogens. Here we confirmed that microbial community composition and the morphology of EAB on the electrode including the thickness and porosity of the biofilm are critical for the performance of BES, and these properties can be simply controlled by the substrate concentration during EAB formation. The EAB formed with 0.1 g/L of acetate (EAB-0.1) exhibited a 90% higher current density than that formed with 1.0 g/L acetate (EAB-1.0). EAB-0.1 had a 50% higher electroactivity per biomass and a 20% thinner thickness than EAB-1.0, which was partly due to the 54% decrease of insulative polysaccharide in biofilm. Limited acetate also imposed a selective pressure to enrich Geobacter up to 88% compared to 72% when acetate was abundant. Our findings demonstrate that a highly active EAB can be formed by limiting substrate concentration, providing a broader understanding of the EAB formation process, the ecology of interspecies competitions and potential applications for bioenergy recovery and trace toxicant detection in the future.},
}
@article {pmid32292058,
year = {2020},
author = {Janek, T and Drzymała, K and Dobrowolski, A},
title = {In vitro efficacy of the lipopeptide biosurfactant surfactin-C15 and its complexes with divalent counterions to inhibit Candida albicans biofilm and hyphal formation.},
journal = {Biofouling},
volume = {36},
number = {2},
pages = {210-221},
doi = {10.1080/08927014.2020.1752370},
pmid = {32292058},
issn = {1029-2454},
abstract = {Surfactin is a type of cyclic lipopeptide biosurfactant implicated in a wide range of applications. Although its antimicrobial activity has been characterized, its effect on Candida albicans physiology remains to be elucidated. The present study evaluated the influence of surfactin-C15 (SF) and its complexes with divalent counterions on C. albicans biofilm formation and preformed biofilms. The SF and metal(II)-SF complexes inhibited biofilm formation and reduced the metabolic activity of mature biofilms in a concentration-dependent manner. The same concentrations of the compounds studied dislodged preexisting biofilms grown on polystyrene plates. Moreover, SF and its metal(II) complexes reduced the mRNA expression of hypha-specific genes HWP1, ALS1, ALS3, ECE1 and SAP4 without exhibiting significant growth inhibition. Further research showed that the compounds tested reduced cellular surface hydrophobicity (CSH). These results suggest that SF and metal(II)-SF complexes could be used as anti-biofilm agents against C. albicans hypha-related infections in clinical practice.},
}
@article {pmid32290861,
year = {2020},
author = {Aldrich, AL and Heim, CE and Shi, W and Fallet, RW and Duan, B and Kielian, T},
title = {TLR2 and caspase-1 signaling are critical for bacterial containment but not clearance during craniotomy-associated biofilm infection.},
journal = {Journal of neuroinflammation},
volume = {17},
number = {1},
pages = {114},
pmid = {32290861},
issn = {1742-2094},
support = {R01 NS107369/NS/NINDS NIH HHS/United States ; R01NS107369/NS/NINDS NIH HHS/United States ; },
abstract = {BACKGROUND: A craniotomy is required to access the brain for tumor resection or epilepsy treatment, and despite precautionary measures, infectious complications occur at a frequency of 1-3%. Approximately half of craniotomy infections are caused by Staphylococcus aureus (S. aureus) that forms a biofilm on the bone flap, which is recalcitrant to antibiotics. Our prior work in a mouse model of S. aureus craniotomy infection revealed a critical role for myeloid differentiation factor 88 (MyD88) in bacterial containment and pro-inflammatory mediator production. Since numerous receptors utilize MyD88 as a signaling adaptor, the current study examined the importance of Toll-like receptor 2 (TLR2) and TLR9 based on their ability sense S. aureus ligands, namely lipoproteins and CpG DNA motifs, respectively. We also examined the role of caspase-1 based on its known association with TLR signaling to promote IL-1β release.<br><br>METHODS: A mouse model of craniotomy-associated biofilm infection was used to investigate the role of TLR2, TLR9, and caspase-1 in disease progression. Wild type (WT), TLR2 knockout (KO), TLR9 KO, and caspase-1 KO mice were examined at various intervals post-infection to quantify bacterial burden, leukocyte recruitment, and inflammatory mediator production in the galea, brain, and bone flap. In addition, the role of TLR2-dependent signaling during microglial/macrophage crosstalk with myeloid-derived suppressor cells (MDSCs) was examined.<br><br>RESULTS: TLR2, but not TLR9, was important for preventing S. aureus outgrowth during craniotomy infection, as revealed by the elevated bacterial burden in the brain, galea, and bone flap of TLR2 KO mice concomitant with global reductions in pro-inflammatory mediator production compared to WT animals. Co-culture of MDSCs with microglia or macrophages, to model interactions in the brain vs. galea, respectively, also revealed a critical role for TLR2 in triggering pro-inflammatory mediator production. Similar to TLR2, caspase-1 KO animals also displayed increased S. aureus titers coincident with reduced pro-inflammatory mediator release, suggestive of pathway cooperativity. Treatment of caspase-1 KO mice with IL-1β microparticles significantly reduced S. aureus burden in the brain and galea compared to empty microparticles, confirming the critical role of IL-1β in limiting S. aureus outgrowth during craniotomy infection.<br><br>CONCLUSIONS: These results demonstrate the existence of an initial anti-bacterial response that depends on both TLR2 and caspase-1 in controlling S. aureus growth; however, neither pathway is effective at clearing infection in the WT setting, since craniotomy infection persists when both molecules are present.},
}
@article {pmid32290491,
year = {2020},
author = {Przekwas, J and Wiktorczyk, N and Budzyńska, A and Wałecka-Zacharska, E and Gospodarek-Komkowska, E},
title = {Ascorbic Acid Changes Growth of Food-Borne Pathogens in the Early Stage of Biofilm Formation.},
journal = {Microorganisms},
volume = {8},
number = {4},
pages = {},
pmid = {32290491},
issn = {2076-2607},
support = {UPB 523//Uniwersytet Mikolaja Kopernika w Toruniu/ ; },
abstract = {Since bacterial biofilm may contribute to the secondary contamination of food during the manufacturing/processing stage there is a need for new methods allowing its effective eradication. Application of food additives such as vitamin C already used in food industry as antioxidant food industry antioxidants may be a promising solution. The aim of this research was evaluation of the impact of vitamin C (ascorbic acid), in a range of concentrations 2.50 µg mL-1-25.0 mg mL-1, on biofilms of Staphylococcus aureus, Escherichia coli, and Listeria monocytogenes strains isolated from food. The efficacy of ascorbic acid was assessed based on the reduction of optical density (λ = 595 nm). The greatest elimination of the biofilm was achieved at the concentration of vitamin C of 25.0 mg mL-1. The effect of the vitamin C on biofilm, however, was strain dependent. The concentration of 25.0 mg mL-1 reduced 93.4%, 74.9%, and 40.5% of E. coli, L. monocytogenes, and S. aureus number, respectively. For E. coli and S. aureus lower concentrations were ineffective. In turn, for L.monocytogenes the biofilm inhibition was observed even at the concentration of 0.25 mg mL-1. The addition of vitamin C may be helpful in the elimination of bacterial biofilms. Nonetheless, some concentrations can induce growth of the pathogens, posing risk for the consumers' health.},
}
@article {pmid32289462,
year = {2020},
author = {Anane, YA and Apalata, T and Vasaikar, S and Okuthe, GE and Songca, SP},
title = {In vitro antimicrobial photodynamic inactivation of multidrug-resistant Acinetobacter baumannii biofilm using Protoporphyrin IX and Methylene blue.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {30},
number = {},
pages = {101752},
doi = {10.1016/j.pdpdt.2020.101752},
pmid = {32289462},
issn = {1873-1597},
abstract = {BACKGROUND: Acinetobacter baumannii is a challenging pathogen due to the rapid development of antimicrobial resistance and biofilm formation. The objective of this study was to evaluate the effect of antimicrobial photodynamic inactivation against biofilms of multidrug-resistant A. baumannii isolated from clinical, abattoir and aquatic sources.<br><br>METHODS: The isolates were tested for susceptibility to imipenem, meropenem, tigecycline and colistin using autoSCAN-4 automated system and rechecked by the E-test. Methylene blue, Protoporphyrin IX, and a halogen lamp were used in the in vitro assay against biofilms of the isolates. The antimicrobial photodynamic inactivation was assessed by counting colony-forming units (CFU).<br><br>RESULTS: The isolates from abattoir and aquatic sources were resistant to carbapenems (>64 μg/mL) but susceptible to tigecycline (2 μg/mL) and colistin (Abattoir, 0.35 μg/mL and Aquatic, 0.24 μg/mL), whereas the clinical isolate was susceptible to only colistin (0.5 μg/mL) using the E-test. The log survival percentages of the control group at a concentration of 20 μM were 5 × 10-6 % for Protoporphyrin IX and 2 × 10-6 % for Methylene blue. Therefore, Methylene blue showed higher bacterial reduction of 7.0 log10 colony forming units than 6.0 log10 for Protoporphyrin IX. No significant difference was observed with respect to the origin of isolates and the minimum inhibitory concentrations.<br><br>CONCLUSION: The results indicate that antimicrobial photodynamic inactivation could be an alternative strategy for the control of infections caused by multi-drug resistant A. baumannii by significantly reducing biofilm growth at a sub-lethal concentrations.},
}
@article {pmid32289218,
year = {2020},
author = {Amin, M and Rowley-Neale, S and Shalamanova, L and Lynch, S and Wilson-Nieuwenhuis, JT and El Mohtadi, M and Banks, CE and Whitehead, KA},
title = {Molybdenum Disulfide Surfaces to Reduce Staphylococcus aureus and Pseudomonas aeruginosa Biofilm Formation.},
journal = {ACS applied materials &amp; interfaces},
volume = {12},
number = {18},
pages = {21057-21069},
doi = {10.1021/acsami.0c02278},
pmid = {32289218},
issn = {1944-8252},
abstract = {The reduction of bacteria and biofilm formation is important when designing surfaces for use in industry. Molybdenum disulfide surfaces (MoS2SUR) were produced using MoS2 particle (MoS2PAR) sizes of 90 nm, 2 μm, and 6 μm containing MoS2PAR concentrations of 5%, 10%, 15%, and 20%. These were tested to determine the efficacy of the MoS2SUR to impede bacterial retention and biofilm formation of two different types of bacteria, Staphylococcus aureus and Pseudomonas aeruginosa. The MoS2SUR were characterized using Fourier transform infrared spectroscopy, ion-coupled plasma atomic emission spectroscopy, scanning electron microscopy, optical profilometry, and water contact angles. The MoS2SUR made with the smaller 90 nm MoS2PAR sizes demonstrated smaller topographical-shaped features. As the size of the incorporated MoS2PAR increased, the MoS2SUR demonstrated wider surface features, and they were less wettable. The increase in MoS2PAR concentration within the MoS2SUR groups did not affect the surface topography but did increase wettability. However, the increase in MoS2PAR size increased both the surface topography and wettability. The MoS2SUR with the smaller topographical-shaped features influenced the retention of the S. aureus bacteria. Increased MoS2SUR topography and wettability resulted in the greatest reduction in bacterial retention, and the bacteria became more heterogeneously dispersed and less clustered across the surfaces. The surfaces that exhibited decreased bacterial retention (largest particle sizes, largest features, greatest roughness, and most wettable) resulted in decreased biofilm formation. Cytotoxicity testing of the surface using cell viability demonstrated that the MoS2SUR were not toxic against HK-2 cells at MoS2PAR sizes of 90 nm and 2 μm. This work demonstrated that individual surface variables (MoS2SUR topographic shape and roughness, MoS2PAR size, and concentration) decreased bacterial loading on the surfaces, which then decreased biofilm formation. By optimizing MoS2SUR properties, it was possible to impede bacterial retention and subsequent biofilm formation.},
}
@article {pmid32285904,
year = {2020},
author = {Bhatia, E and Banerjee, R},
title = {Hybrid silver-gold nanoparticles suppress drug resistant polymicrobial biofilm formation and intracellular infection.},
journal = {Journal of materials chemistry. B},
volume = {8},
number = {22},
pages = {4890-4898},
doi = {10.1039/d0tb00158a},
pmid = {32285904},
issn = {2050-7518},
abstract = {Over decades bacteria have evolved multiple mechanisms to fight antibiotics. Biofilm formation by bacteria is one such mechanism as it forms a barrier and creates an acidic environment that reduces the efficiency of antimicrobials. Bacteria have also developed the ability to persist intracellularly within mammalian cells, causing recurrent infections. Many antibiotics are rendered ineffective due to poor penetration across biofilms and within mammalian cells. In this study, silver-gold hybrid nanoparticles were developed as anti-microbial agents to combat biofilm formation and intracellular infections. Biogenic hybrid silver gold nanoparticles were developed in an organic solvent free single reaction mixture using quercetin, a flavonoid, as the reducing and stabilizing agent. Silver-gold nanoparticles of 40 ± 10 nm diameter were effective against a broad spectrum of bacteria with minimum bactericidal concentrations of 10 μg ml-1 and 20 μg ml-1 for Gram negative and Gram-positive organisms, respectively. These nanoparticles were also effective against mixed infections at 20 μg ml-1. Their mode of action involves generating intracellular oxidative stress in both Gram negative and Gram-positive bacteria, which causes damage to the cell wall. Polymicrobial biofilm formation was suppressed and intracellular infection was reduced by 70% to 90% in fibroblast and monocyte cell lines. These results indicate that hybrid silver gold nanoparticles are promising agents to suppress biofilm formation and tackle intracellular infections.},
}
@article {pmid32284373,
year = {2020},
author = {Chen, HH and Chang, CC and Yuan, YH and Liaw, SJ},
title = {A CpxR-Regulated zapD Gene Involved in Biofilm Formation of Uropathogenic Proteus mirabilis.},
journal = {Infection and immunity},
volume = {88},
number = {7},
pages = {},
doi = {10.1128/IAI.00207-20},
pmid = {32284373},
issn = {1098-5522},
abstract = {Proteus mirabilis, a frequent uropathogen, forms extensive biofilms on catheters that are infamously difficult to treat. To explore the mechanisms of biofilm formation by P. mirabilis, we performed in vivo transposon mutagenesis. A mutant with impaired biofilm formation was isolated. The mutant was found to have Tn5 inserted in the zapD gene, encoding an outer membrane protein of the putative type 1 secretion system ZapBCD. zapBCD and its upstream zapA gene, encoding a protease, constitute an operon under the control of CpxR, a two-component regulator. The cpxR mutant and zapA mutant strains also had a biofilm-forming defect. CpxR positively regulates the promoter activities of zapABCD, cpxP, and cpxR An electrophoretic mobility shift assay revealed that CpxR binds zapA promoter DNA. The loss of zapD reduced CpxR-regulated gene expression of cpxR, zapA, cpxP, and mrpA, the mannose-resistant Proteus-like (MR/P) fimbrial major subunit gene. The restoration of biofilm formation in the zapD mutant with a CpxR-expressing plasmid reinforces the idea that CpxR-mediated gene expression contributes to zapD-involved biofilm formation. In trans expression of zapBCD from a zapBCD-expressing plasmid also reestablished the biofilm formation ability of the cpxR mutant to a certain level. The zapD and cpxR mutants had significantly lower protease activity, adhesion, and autoaggregation ability and production of exopolysaccharides and extracellular DNA (eDNA) than did the wild type. Finally, we identified copper as a signal for CpxR to increase biofilm formation. The loss of cpxR or zapD abolished the copper-mediated biofilm upshift. CpxR was required for copper-induced expression of zapA and cpxR Taken together, these data highlight the important role of CpxR-regulated zapD in biofilm formation and the underlying mechanisms in P. mirabilis.},
}
@article {pmid32283494,
year = {2020},
author = {Vyas, N and Wang, QX and Manmi, KA and Sammons, RL and Kuehne, SA and Walmsley, AD},
title = {How does ultrasonic cavitation remove dental bacterial biofilm?.},
journal = {Ultrasonics sonochemistry},
volume = {67},
number = {},
pages = {105112},
doi = {10.1016/j.ultsonch.2020.105112},
pmid = {32283494},
issn = {1873-2828},
abstract = {Bacterial biofilm accumulation is problematic in many areas, leading to biofouling in the marine environment and the food industry, and infections in healthcare. Physical disruption of biofilms has become an important area of research. In dentistry, biofilm removal is essential to maintain health. The aim of this study is to observe biofilm disruption due to cavitation generated by a dental ultrasonic scaler (P5XS, Acteon) using a high speed camera and determine how this is achieved. Streptococcus sanguinis biofilm was grown on Thermanox™ coverslips (Nunc, USA) for 4 days. After fixing and staining with crystal violet, biofilm removal was imaged using a high speed camera (AX200, Photron). An ultrasonic scaler tip (tip 10P) was held 2 mm away from the biofilm and operated for 2 s. Bubble oscillations were observed from high speed image sequences and image analysis was used to track bubble motion and calculate changes in bubble radius and velocity on the surface. The results demonstrate that most of the biofilm disruption occurs through cavitation bubbles contacting the surface within 2 s, whether individually or in cavitation clouds. Cleaning occurs through shape oscillating microbubbles on the surface as well as through fluid flow.},
}
@article {pmid32283260,
year = {2020},
author = {Xi, D and Yang, S and Liu, Q and Li, Y and Li, Y and Yan, J and Wang, X and Ning, K and Cao, B},
title = {The response regulator ArcA enhances biofilm formation in the vpsT manner under the anaerobic condition in Vibrio cholerae.},
journal = {Microbial pathogenesis},
volume = {144},
number = {},
pages = {104197},
doi = {10.1016/j.micpath.2020.104197},
pmid = {32283260},
issn = {1096-1208},
abstract = {Vibrio cholerae, the agent of severe diarrheal disease cholera, is known to form biofilm to persist in the environmental and the host,s intestines. The bacteria execute a complex regulatory pathway producing virulence factors that allow colonization and cause disease in response to environmental signals in the intestine, including low oxygen-limited condition. VpsR and VpsT are primary regulators of the biofilm formation-regulatory network. In this study, we determined that anaerobic induction enhanced biofilm formation via the two component system, ArcB/A, which functions as a positive regulator of toxT expression. The biofilm formation has reduced approximately 2.4-fold in the ΔarcA mutant compared to the wild type in anaerobic condition. Chip-qPCR and EMSA assays confirmed that ArcA can bind directly to the vpsT promoter and then activates the expression of biofilm formation related genes, vpsA-K and vpsL-Q. Meanwhile, the ΔarcA mutant decreased the ability of colonization in intestine with CI (competition index) of 0.27 compared to wild type strain. These results suggest that ArcA links the expression of virulence and biofilm synthesis genes during anaerobic condition, and contributes to understand the complex relationship between biofilm formation and the intestinal signals during infection.},
}
@article {pmid32283258,
year = {2020},
author = {Zhao, F and Yang, H and Bi, D and Khaledi, A and Qiao, M},
title = {A systematic review and meta-analysis of antibiotic resistance patterns, and the correlation between biofilm formation with virulence factors in uropathogenic E. coli isolated from urinary tract infections.},
journal = {Microbial pathogenesis},
volume = {144},
number = {},
pages = {104196},
doi = {10.1016/j.micpath.2020.104196},
pmid = {32283258},
issn = {1096-1208},
abstract = {Urinary tract infection (UTI) is caused by the invasion of the pathogen in the urinary system that can manifest as symptomatic or asymptomatic bacteriuria. This study was conducted to investigate antibiotic resistance patterns, and the correlation between biofilm formations with virulence factors in uropathogenic E. coli isolates retrieved from UTI. We searched Scopus and Google Scholar, PubMed, Web of sciences for studies published in the English language between 1st 2005 to 31st December 2019. The Mesh terms and text words included &quot;biofilms&quot;, OR &quot;biofilm formation&quot;, AND &quot;antibiotic resistance&quot;, OR &quot;drug-resistance&quot;, OR &quot;antimicrobial drug resistance&quot;, AND &quot;urinary tract infections&quot;, OR &quot;UTI&quot;, AND &quot;biofilm related-genes&quot;, AND &quot;virulence factors&quot; AND &quot;correlation&quot;, AND &quot;Uropathogenic Escherichia coli&quot;, OR &quot;Uropathogenic E. coli&quot; AND &quot;prevalence&quot; AND &quot;Iran&quot;. Data analyzed using Comprehensive Meta-Analysis (CMA) software. The random-effects model was used to calculate the pooled prevalence with 95% confidence interval (CI). The combined rates of biofilm formation in Uropathogenic E. coli (UPEC) isolates were achieved as 84.6% (95% CI: 72.7-91.9). Also, 24.8%, 26.1% and 44.6% of UPEC isolates were able to create strong, moderate and weak biofilm, respectively. The highest pooled antibiotic resistance was against Ampicillin followed by Tetracycline with resistance rates of 74.6% and 64.9%, respectively. Accordingly, some studies reported that biofilm production was significantly associated with antibiotic resistance and virulence genes (p < 0.05). This study showed a high tendency among UPEC isolates to form biofilm (more than 84%), also, most studies included in the present review reported a significant correlation between biofilm formation with antibiotic resistance and virulence factors.},
}
@article {pmid32281883,
year = {2020},
author = {Talluri, SNL and Winter, RM and Salem, DR},
title = {Conditioning film formation and its influence on the initial adhesion and biofilm formation by a cyanobacterium on photobioreactor materials.},
journal = {Biofouling},
volume = {36},
number = {2},
pages = {183-199},
doi = {10.1080/08927014.2020.1748186},
pmid = {32281883},
issn = {1029-2454},
abstract = {Although cyanobacteria are a common group of microorganisms well-suited to utilization in photobioreactors (PBRs), studies of cyanobacteria fouling and its prevention are scarce. Using a cyanobacterium, Anabaena sp. PCC 7120, which had been genetically modified to enhance linalool production, the formation of conditioning films and the effects of these on the physico-chemical surface properties of various PBR materials during initial adhesion and biofilm formation were investigated. The adhesion assay revealed that the overall attachment of Anabaena was substratum dependent and no correlation between the hydrophobicity/roughness of clean material and cell attachment was found. Surface hydrophilicity/hydrophobicity of all the materials changed within 12 h due to formation of conditioning films. ATR-FTIR spectroscopy revealed that the fractional change in protein deposition between 12 to 96 h was consistent with Anabaena cell attachment but polysaccharide deposition was material specific and did not correlate with cell attachment on the PBR materials. Also, the delay in conditioning film proteins on PVC and PTFE indicated that components other than proteins may be responsible for the decrease in contact angles on these surfaces within 12 h. This indicates the important role of the chemical nature of adsorbed conditioning films in determining the initial attachment of Anabaena to PBR materials. The lower rate of attachment of Anabaena on the hydrophilic surfaces (glass and PMMA) between 72 h to 96 h (regime 3) showed that these surfaces could potentially have low fouling characteristics at extended time scales and should be considered for further research.},
}
@article {pmid32280870,
year = {2020},
author = {Fallah Atanaki, F and Behrouzi, S and Ariaeenejad, S and Boroomand, A and Kavousi, K},
title = {BIPEP: Sequence-based Prediction of Biofilm Inhibitory Peptides Using a Combination of NMR and Physicochemical Descriptors.},
journal = {ACS omega},
volume = {5},
number = {13},
pages = {7290-7297},
pmid = {32280870},
issn = {2470-1343},
abstract = {Biofilms are biological systems that are formed by a community of microorganisms in which microbial cells are connected on a surface within a self-produced matrix of an extracellular polymeric substance. On some occasions, microorganisms use biofilms to protect themselves against the harmful effects of the host body immune system and the surrounding environment, hence increasing their chances of survival against the various anti-microbial agents. Biofilms play a crucial role in medicine and industry because of the problems they cause. Designing agents that inhibit bacterial biofilm formation is very costly and takes too much time in the laboratory to be discovered and validated. Therefore, developing computational tools for the prediction of biofilm inhibitor peptides is inevitable and important. Here, we present a computational prediction tool to screen the vast number of peptide sequences and select potential candidate peptides for further lab experiments and validation. In this learning model, different feature vectors, extracted from the peptide primary structure, are exploited to learn patterns from the sequence of biofilm inhibitory peptides. Various classification algorithms including SVM, random forest, and k-nearest neighbor have been examined to evaluate their performance. Overall, our approach showed better prediction in comparison with other prediction methods. In this study, for the first time, we applied features extracted from NMR spectra of amino acids along with physicochemical features. Although each group of features showed good discrimination potential alone, we used a combination of features to enhance the performance of our method. Our prediction tool is freely available.},
}
@article {pmid32279616,
year = {2020},
author = {Aramwit, P and Napavichayanum, S and Pienpinijtham, P and Rasmi, Y and Bang, N},
title = {Antibiofilm activity and cytotoxicity of silk sericin against Streptococcus mutans bacteria in biofilm: an in vitro study.},
journal = {Journal of wound care},
volume = {29},
number = {Sup4},
pages = {S25-S35},
doi = {10.12968/jowc.2020.29.Sup4.S25},
pmid = {32279616},
issn = {0969-0700},
abstract = {OBJECTIVE: To investigate the potential of sericin extracted by different methods to inhibit biofilm formation (prevention) and disrupt already formed biofilm (treatment).<br><br>METHOD: In this in vitro study, sericin was extracted by heat, acid, alkali and urea. Streptococcus mutans bacteria were cultivated in the presence of various concentrations of sericin to evaluate antibiofilm formation using cell density assay (inhibition effect before biofilm formed). Conversely, various concentrations of sericin were added to a biofilm already formed by Streptococcus mutans bacteria, and the viability of bacteria assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay (disruption effects after biofilm formed). Structures of extracted sericin were evaluated using circular dichroism and Fourier-transform infrared spectrometer.<br><br>RESULTS: The urea-extracted sericin at all concentrations (12.5mg/ml, 25mg/ml, 50mg/ml and 100mg/ml) showed the highest potential antibiofilm activity in terms of both inhibition and disruption effects, compared with sericin extracted by heat, acid or alkali. The heat-extracted and acid-extracted sericin were found to reduce the biofilm formation dose-dependently, while the alkali-extracted sericin did not show either inhibition or disruption effect on the bacterial biofilm. The urea-extracted sericin also killed the bacteria residing within the biofilm, possibly due to its modified structure which may destabilise the bacterial cell wall, leading to membrane disintegration and, finally, cell death.<br><br>CONCLUSION: Our results demostrated the antibiofilm activity of sericin. This could form the basis of further research on the mechanism and application of sericin as a novel antibiofilm agent.},
}
@article {pmid32279402,
year = {2020},
author = {Di Marco, NI and Pungitore, CR and Lucero-Estrada, CSM},
title = {Aporphinoid alkaloids inhibit biofilm formation of Yersinia enterocolitica isolated from sausages.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14664},
pmid = {32279402},
issn = {1365-2672},
support = {PROICO 02-1518//Science and Technology Department, National University of San Luis, Argentina/ ; PROICO 02-2516//Science and Technology Department, National University of San Luis, Argentina/ ; PROICO 2-0914//Science and Technology Department, National University of San Luis, Argentina/ ; //Alexander von Humboldt Foundation/ ; PICT-2015-1722//National Agency for Scientific and Technological Promotion, Argentina/ ; PICT-2017-0785//National Agency for Scientific and Technological Promotion, Argentina/ ; //CONICET/ ; //National University of San Luis/ ; },
abstract = {AIMS OF THE STUDY: The ability of Yersinia enterocolitica strains to form biofilms and the capacity of different alkaloids to inhibit biofilm formation were investigated.<br><br>METHODS AND RESULTS: The capacity to form biofilm on polystyrene of 31 Y. enterocolitica strains was evaluated. Biofilm and quorum sensing (QS) inhibition of 17 alkaloids were assayed; furthermore, minimum biofilm inhibitory concentration (MBIC) was determined. The capacity to form biofilms among the examined strains seemed to be a strain-related feature. The best biofilm inhibitors at 100 µmol l-1 were oliverine (1), guatterine (3), liriodenine (4), oliveridine (5) and pachypodanthine (6), which showed biofilm inhibition higher than 87%. Pachypodanthine (6) was the most effective compound with MBIC value of 12·5 µmol l-1 at subinhibitory concentration and also was able to inhibit QS system and reduce yenR expression at this concentration.<br><br>CONCLUSION: This is the first study to demonstrate that oliverine, liriodenine, and pachypodanthine are able to inhibit biofilm formation of Y. enterocolitica without critically disturbing its growing capacity. At MBIC, pachypodanthine inhibited biofilm formation and QS.<br><br>The use of aporphinoid alkaloids as biofilms inhibitory agents might potentially be useful to treat biofilm-associated infections in the future.},
}
@article {pmid32279229,
year = {2020},
author = {Kumbar, VM and Peram, MR and Kugaji, MS and Shah, T and Patil, SP and Muddapur, UM and Bhat, KG},
title = {Effect of curcumin on growth, biofilm formation and virulence factor gene expression of Porphyromonas gingivalis.},
journal = {Odontology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10266-020-00514-y},
pmid = {32279229},
issn = {1618-1255},
abstract = {Porphyromonas gingivalis is a keystone pathogen and major colonizer in host tissue which plays a pivotal role in periodontitis among the other polymicrobial infections. Increasing facts demonstrate that curcumin has antibacterial activity and anti-biofilm effect against the periodontopathogens through diverse mechanisms that have a positive impact on periodontal health. The present study was aimed to elucidate the effect of curcumin on biofilm formation and virulence factor gene expression of P. gingivalis. By using gene expression studies, we exploited the mechanism of anti-biofilm effects of curcumin on P. gingivalis. The minimum inhibitory concentration and minimum bactericidal concentration of curcumin for both ATCC and clinical strains of P. gingivalis were found to be 62.5 and 125 µg ml-1 respectively. Curcumin prevented bacterial adhesion and biofilm formation in a dose-dependent manner. Further, curcumin attenuated the virulence of P. gingivalis by reducing the expression of genes coding for major virulence factors, including adhesions (fimA, hagA, and hagB) and proteinases (rgpA, rgpB, and kgp). The results indicated that curcumin has shown anti-biofilm as well as antibacterial activity against P. gingivalis. Further, curcumin because of its pleiotropic actions could be a simple and inexpensive therapeutic strategy in the treatment of periodontal disease.},
}
@article {pmid32278760,
year = {2020},
author = {Zhang, Z and Lyu, X and Xu, Q and Li, C and Lu, M and Gong, T and Tang, B and Wang, L and Zeng, W and Li, Y},
title = {Utilization of the extract of Cedrus deodara (Roxb. ex D.Don) G. Don against the biofilm formation and the expression of virulence genes of cariogenic bacterium Streptococcus mutans.},
journal = {Journal of ethnopharmacology},
volume = {257},
number = {},
pages = {112856},
doi = {10.1016/j.jep.2020.112856},
pmid = {32278760},
issn = {1872-7573},
abstract = {Cedrus deodara (Roxb. ex D.Don) G. Don is applied as anti-inflammatory and anti-infection agents in folklore medicine.<br><br>AIM OF THE STUDY: The present study aimed to assess the antimicrobial activity of Cedrus deodara (Roxb. ex D.Don) G. Don extract (CDE) against Streptococcus mutans biofilm formation and its biocompatibility, as well as to identify its chemical components.<br><br>MATERIALS AND METHODS: Confocal laser scanning microscopy (CLSM), crystal violet staining, and CFU counting assay were applied to investigate the effect of CDE on S. mutans biofilm formation and extracellular polysaccharides (EPS) synthesis. The microstructure of S. mutans biofilms formed on glass coverslips and bovine enamel treated with CDE was observed by scanning electron microscopy (SEM). qRT-PCR was used to measure the expression of virulence genes gtfB, gtfC, and gtfD, and zymogram assay was performed to investigate the enzymatic activity of Gtfs. Moreover, HPLC-MS and NMR were applied to identify its chemical components. CCK-8 assay was also performed on human oral cells to evaluate its biocompatibility.<br><br>RESULTS: Under the treatment of CDE, S. mutans formed less biofilm on both coverslips and enamel surfaces and synthesized less EPS. Moreover, CDE downregulated the expression of gtf genes and inhibited the enzymatic activity of Gtfs. According to HPLC-MS and NMR results, molecular structures of six main compounds in CDE were identified. CDE also has a good biocompatibility.<br><br>CONCLUSIONS: CDE exhibits inhibitory activity against S. mutans and a good biocompatibility. It has the potential to be developed as anti-caries agents for clinical use.},
}
@article {pmid32278165,
year = {2020},
author = {Wang, J and Zhou, J and Wang, Y and Wen, Y and He, L and He, Q},
title = {Efficient nitrogen removal in a modified sequencing batch biofilm reactor treating hypersaline mustard tuber wastewater: The potential multiple pathways and key microorganisms.},
journal = {Water research},
volume = {177},
number = {},
pages = {115734},
doi = {10.1016/j.watres.2020.115734},
pmid = {32278165},
issn = {1879-2448},
mesh = {Ammonia ; Biofilms ; Bioreactors ; Denitrification ; Mustard Plant ; Nitrification ; *Nitrogen ; *Waste Water ; },
abstract = {This study first compared the efficiencies and mechanisms of the nitrogen removal in an aerobic sequencing batch biofilm reactor (SBBR) treating mustard tuber wastewater from high salt (30 gNaCl L-1) to ultra-high salt (70 gNaCl L-1). High-efficiency maintaining of nitrification was observed. Despite of high BOD5/TN (5.5-9), distinct denitrification decline for lack of carbon in response to salt stress was observed. Considering the high concentrations of sulfate in mustard wastewater, and the existence of sulfur-reducing bacteria (SRB) and sulfur-driven denitrifiers (DNSOB) in the aerobic SBBR, sulfate reduction-sulfur autotrophic denitrification process is a feasible idea to solve this problem. By modified to intermittent aeration mode, sulfur cycle was developed in SBBR. The average removal efficiency of COD, TN reached 85.20% and 98.56%, respectively. By batch activity tests and microbial community analysis, ammonia oxidation activity by ammonia-oxidizing archaea (AOA) was observed, and high abundance of AOA (Arch-amoA/AOB amoA: 2.38 × 102) together with ammonia-oxidizing bacteria (AOB) of Nitrosomonas_halophila (1.23%) ensured the high efficient nitrification. After running mode change, specific sulfur-driven NO3--N reduction rate increased and the abundance of dominant SRB and DNSOB rose from 3.95% to 10.79% and 2.22% to 9.95%, respectively. The sulfate-reducing process during anaerobic phase provided electron donors for subsequent autotrophic denitrification, making outlet NO3--N concentrations reduced from 18.26 mg L-1 to 1.93 mg L-1. The sulfur activity batch test showed that 73.80%∼80.92% of sulfate were circulation utilized, and rest of them conversed to the gaseous H2S and S0. In addition to DNSOB, anoxic denitrifier of Halomonas (22.91%), aerobic denitrifier of Phaeodactylibacter (2.75%) and endogenous denitrifier of Defluviicoccus (3.18%) were also dominant heterotrophic bacteria (all halophilic or halotolerant) in the intermittent aeration SBBR. Batch activity tests and periodic laws have also verified the existence of corresponding denitrification pathways. This study shows that the enrichment of special halophilic functional bacteria with multiple nitrogen removal pathways is a good idea for the efficient treatment of high-concentrated hypersaline industrial wastewater.},
}
@article {pmid32277108,
year = {2020},
author = {Cai, YM and Hutchin, A and Craddock, J and Walsh, MA and Webb, JS and Tews, I},
title = {Differential impact on motility and biofilm dispersal of closely related phosphodiesterases in Pseudomonas aeruginosa.},
journal = {Scientific reports},
volume = {10},
number = {1},
pages = {6232},
pmid = {32277108},
issn = {2045-2322},
abstract = {In Pseudomonas aeruginosa, the transition between planktonic and biofilm lifestyles is modulated by the intracellular secondary messenger cyclic dimeric-GMP (c-di-GMP) in response to environmental conditions. Here, we used gene deletions to investigate how the environmental stimulus nitric oxide (NO) is linked to biofilm dispersal, focusing on biofilm dispersal phenotype from proteins containing putative c-di-GMP turnover and Per-Arnt-Sim (PAS) sensory domains. We document opposed physiological roles for the genes ΔrbdA and Δpa2072 that encode proteins with identical domain structure: while ΔrbdA showed elevated c-di-GMP levels, restricted motility and promoted biofilm formation, c-di-GMP levels were decreased in Δpa2072, and biofilm formation was inhibited, compared to wild type. A second pair of genes, ΔfimX and ΔdipA, were selected on the basis of predicted impaired c-di-GMP turnover function: ΔfimX showed increased, ΔdipA decreased NO induced biofilm dispersal, and the genes effected different types of motility, with reduced twitching for ΔfimX and reduced swimming for ΔdipA. For all four deletion mutants we find that NO-induced biomass reduction correlates with increased NO-driven swarming, underlining a significant role for this motility in biofilm dispersal. Hence P. aeruginosa is able to differentiate c-di-GMP output using structurally highly related proteins that can contain degenerate c-di-GMP turnover domains.},
}
@article {pmid32276211,
year = {2020},
author = {Qian, W and Yang, M and Li, X and Sun, Z and Li, Y and Wang, X and Wang, T},
title = {Anti-microbial and anti-biofilm activities of combined chelerythrine-sanguinarine and mode of action against Candida albicans and Cryptococcus neoformans in vitro.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {191},
number = {},
pages = {111003},
doi = {10.1016/j.colsurfb.2020.111003},
pmid = {32276211},
issn = {1873-4367},
abstract = {The increasing prevalence of fungal infections coupled with emerging drug resistance has stimulated an urgent need to explore new and effective antifungal agents. Sanguinarine and chelerythrine constitute alkaloids that have exhibited antifungal activities. However, the effects of a 1:1 mixture of these agents against Candida albicans and Cryptococcus neoformans have remained largely unexplored. The purpose of this study was to assess the anti-fungal and anti-biofilm efficacy of combined chelerythrine-sanguinarine against C. albicans and C. neoformans in vitro. Combined chelerythrine-sanguinarine inhibited C. albicans and C. neoformans growth with minimum inhibitory concentrations (MICs) of 2 and 16 μg/mL, respectively, and effectively inhibited adhesion and biofilm formation of these pathogens at minimum biofilm inhibitory concentrations of 1 and 8 μg/mL. Notably, the mixture significantly eradicated mature C. albicans and C. neoformans biofilms at 8 and 128 μg/mL, respectively. In particular, the mixture was found to disrupt cell membrane integrity and enhance penetration of antibiotics into fungal cells, suggesting its antifungal mode of action. Hence, combined chelerythrine-sanguinarine shows promise as a potential anti-fungal and anti-biofilm agent for the management of serious infections caused by C. albicans and C. neoformans.},
}
@article {pmid32276085,
year = {2020},
author = {Song, X and Pan, H and Wang, H and Liao, X and Sun, D and Xu, K and Chen, T and Zhang, X and Wu, M and Wu, D and Gao, Y},
title = {Identification of new dermaseptins with self-assembly tendency: membrane disruption, biofilm eradication, and infected wound healing efficacy.},
journal = {Acta biomaterialia},
volume = {109},
number = {},
pages = {208-219},
doi = {10.1016/j.actbio.2020.03.024},
pmid = {32276085},
issn = {1878-7568},
abstract = {Severe infections associated with antibiotic-resistant bacteria and biofilms have attracted increasing interest as these diseases are difficult to treat with current antibiotics. Typical cationic antimicrobial peptides dermaseptins are considered to be the most promising next-generation antibiotics because of their broad-spectrum antimicrobial activities and minor side effects. Two new dermaseptin peptides, DMS-PS1 and DMS-PS2, have been identified by &quot;shotgun&quot; molecular cloning of encoding cDNAs in the crude skin secretions of the waxy monkey tree frog, Phyllomedusa sauvagei. The mature peptide sequences predicted from the cloned cDNAs were separated from crude skin secretions and confirmed by mass spectrometry. Chemically synthetic replicates were assessed for various biological activities. Both dermaseptins were potently effective against a broad spectrum of microorganisms including antibiotic-resistant bacteria and displayed significant potency against gram-positive and gram-negative bacterial biofilms with low toxicity towards mammalian red blood cells. Remarkably, DMS-PS2 was effective against infections in murine skin caused by methicillin-resistant Staphylococcus aureus as a result of an induced wound. The actions of DMS-PS2 were with a membrane permeabilization mode. Overall, the data provided convincing evidence for the development of anti-infectious agents and/or biomaterials as a new therapeutic approach against bacterial infections. STATEMENT OF SIGNIFICANCE: Bacterial adhesion to biomaterials remains a major problem. Antimicrobial peptides (AMPs) are well-known components of the innate immune system that can be applied to overcome biofilm-associated infections. Cationic dermaseptin peptides showed significant broad-spectrum antimicrobial activities and activities against bacterial biofilms of persistent infections in association with weak toxicity for mammalian red blood cells. The membrane permeabilizing ability of DMS-PS2 was confirmed, and importantly, it demonstrated potent efficiency of the treatment of MRSA infected murine skin model. Furthermore, beyond our expectation, DMS-PS2 showed a self-aggregating parameter, indicating a promising potential for the use of immobilized AMPs in clinical applications., which makes it also a promising suggestion for infection-proof biomaterial development.},
}
@article {pmid32272740,
year = {2020},
author = {Guła, G and Szymanowska, P and Piasecki, T and Góras, S and Gotszalk, T and Drulis-Kawa, Z},
title = {The Application of Impedance Spectroscopy for Pseudomonas Biofilm Monitoring during Phage Infection.},
journal = {Viruses},
volume = {12},
number = {4},
pages = {},
pmid = {32272740},
issn = {1999-4915},
support = {UMO-2016/21/B/NZ6/01157//Narodowe Centrum Nauki/ ; },
abstract = {Bacterial biofilm prevention and eradication are common treatment problems, hence there is a need for advanced and precise experimental methods for its monitoring. Bacterial resistance to antibiotics has resulted in an interest in using a natural bacterial enemy-bacteriophages. In this study, we present the application of quartz tuning forks (QTF) as impedance sensors to determine in real-time the direct changes in Pseudomonas aeruginosa PAO1 biofilm growth dynamics during Pseudomonas phage LUZ 19 treatment at different multiplicities of infection (MOI). The impedance of the electric equivalent circuit (EEC) allowed us to measure the series resistance (Rs) corresponding to the growth-medium resistance (planktonic culture changes) and the conductance (G) corresponding to the level of QTF sensor surface coverage by bacterial cells and the extracellular polymer structure (EPS) matrix. It was shown that phage impacts on sessile cells (G dynamics) was very similar in the 10-day biofilm development regardless of applied MOI (0.1, 1 or 10). The application of phages at an early stage (at the sixth h) and on three-day biofilm caused a significant slowdown in biofilm dynamics, whereas the two-day biofilm turned out to be insensitive to phage infection. We observed an inhibitory effect of phage infection on the planktonic culture (Rs dynamics) regardless of the MOI applied and the time point of infection. Moreover, the Rs parameter made it possible to detect PAO1 population regrowth at the latest time points of incubation. The number of phage-insensitive forms reached the level of untreated culture at around the sixth day of infection. We conclude that the proposed impedance spectroscopy technique can be used to measure the physiological changes in the biofilm matrix composition, as well as the condition of planktonic cultures in order to evaluate the activity of anti-biofilm compounds.},
}
@article {pmid32272414,
year = {2020},
author = {Wang, H and Zhang, H and Zhang, K and Qian, Y and Yuan, X and Ji, B and Han, W},
title = {Membrane fouling mitigation in different biofilm membrane bioreactors with pre-anoxic tanks for treating mariculture wastewater.},
journal = {The Science of the total environment},
volume = {724},
number = {},
pages = {138311},
doi = {10.1016/j.scitotenv.2020.138311},
pmid = {32272414},
issn = {1879-1026},
abstract = {This study compared the membrane fouling mitigation in two novel types of biofilm membrane bioreactor coupled with a pre-anoxic tank (BF-AO-MBR)-namely a fixed biofilm membrane bioreactor (FB-MBR) with fiber bundle bio-carriers and a moving-bed biofilm membrane bioreactor (MB-MBR) with suspended bio-carriers-relative to an anoxic/oxic MBR (AO-MBR), at salinities ranging from zero to 60 g/L. The results showed that the FB-MBR mitigated membrane fouling to a greater degree than the MB-MBR and AO-MBR. During operation, the FB-MBR exhibited the lowest fouling development, with three membrane filtration cycles, while the AO-MBR and MB-MBR had 22 and nine cycles, respectively. The key fouling factor in all reactors was cake layer resistance (RC), which contributed to 89.61, 62.20, and 83.17% of the total fouling resistance (RT) in AO-MBR, FB-MBR and MB-MBR, respectively. Additionally, in the FB-MBR, the pore blocking resistance (30.07%) was also an important cause of fouling. Fiber bundle bio-carriers and suspended bio-carriers reduced the RT by 37.68% and 21.24% (mainly the RC) compared to that of AO-MBR. Furthermore, FB-MBR and MB-MBR caused a decrease of suspended biomass (80.14 and 15.90%, respectively), and the latter exhibited a higher sludge particle size than AO-MBR, possibly resulting in the cake layer decline. The studied BF-AO-MBRs further alleviated the fouling propensity by reducing the amount of soluble microbial product (SMP) and extracellular polymeric substances (EPS) under all salinity levels, especially the FB-MBR. Among the protein components, the amounts of tryptophan protein-like substance and aromatic protein-like substance were significantly lower in the FB-MBR compared to the AO-MBR and MB-MBR. Additionally, at 60 g/L salinity, the structure of the microbial community in the FB-MBR had a lower abundance of Bacteroidetes and more biomacromolecule degraders, which may have contributed to the moderation of membrane fouling.},
}
@article {pmid32272386,
year = {2020},
author = {Alves, P and Gomes, LC and Vorobii, M and Rodriguez-Emmenegger, C and Mergulhão, FJ},
title = {The potential advantages of using a poly(HPMA) brush in urinary catheters: effects on biofilm cells and architecture.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {191},
number = {},
pages = {110976},
doi = {10.1016/j.colsurfb.2020.110976},
pmid = {32272386},
issn = {1873-4367},
abstract = {Infections related to bacterial colonization of medical devices are a growing concern given the socio-economical impacts in healthcare systems. Colonization of a device surface with bacteria usually triggers the development of a biofilm, which is more difficult to eradicate than free-floating or adhered bacteria and can act as a reservoir for subsequent infections. Biofilms often harbor Viable but nonculturable (VBNC) cells that are likely to be more resistant to antibiotic treatment and that can become active in more favorable conditions causing infection. Biofilm formation is dependent on different factors, chiefly the properties of the surface and of the surrounding medium, and the hydrodynamic conditions. In this work, the antifouling performance of a poly[N-(2-hydroxypropyl) methacrylamide] (poly(HPMA)) brush was evaluated in vitro in conditions that mimic a urinary catheter using Escherichia coli as a model organism. The results obtained with the brush were compared to those obtained with two control surfaces, polydimethylsiloxane (PDMS) (the most common material for catheters) and glass. A decrease in initial adhesion and surface coverage was observed on the brush. This antifouling behavior was maintained during biofilm maturation and even in a simulated post-bladder infection period when the reduction in total cell number reached 87 %. Biofilms were shown to adapt their architecture during that period and VBNC cells adsorbed weakly on the brushes and were completely washed away. Taken together, these results suggest that the use of the poly(HPMA) brush in urinary tract devices such as catheters and stents may reduce biofilm formation and possibly render the formed biofilms more susceptible to antibiotic treatment and with reduced infectivity potential.},
}
@article {pmid32272212,
year = {2020},
author = {Hamdy, R and Soliman, SSM and Alsaadi, AI and Fayed, B and Hamoda, AM and Elseginy, SA and Husseiny, MI and Ibrahim, AS},
title = {Design and synthesis of new drugs inhibitors of Candida albicans hyphae and biofilm formation by upregulating the expression of TUP1 transcription repressor gene.},
journal = {European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences},
volume = {148},
number = {},
pages = {105327},
doi = {10.1016/j.ejps.2020.105327},
pmid = {32272212},
issn = {1879-0720},
abstract = {Candida albicans is a common human fungal pathogen that causes disease ranging from superficial to lethal infections. C. albicans grows as budding yeast which can transform into hyphae in response to various environmental or biological stimuli. Although both forms have been associated with virulence, the hyphae form is responsible for the formation of multi-drug resistance biofilm. Here, new compounds were designed to selectively inhibit C. albicans hyphae formation without affecting human cells to afford sufficient safety. The newly designed 5-[3-substitued-4-(4-substituedbenzyloxy)-benzylidene]-2-thioxo-thiazolidin-4-one derivatives, named SR, showed very specific and effective inhibition activity against C. albicans hyphae formation. SR compounds caused hyphae inhibition activity at concentrations 10-40 fold lower than the concentration required to inhibit Candida yeast and bacterial growths. The anti-hyphae inhibition activities of SR compounds were via activation of the hyphae transcription repressor gene, TUP1. Correlation studies between the expression of TUP1 gene and the activity of SR compounds confirmed that the anti-C. albicans activities of SR compounds were via inhibition of hyphae formation. The newly designed SR compounds showed 10-40% haemolytic activity on human erythrocytes when compared to 100% haemolysis by 0.1% triton employed as positive control. Furthermore, theoretical prediction of absorption, distribution, metabolism, excretion, and toxicity (ADMET) of SR compounds confirmed their safety, efficient metabolism and possible oral bioavailability. With the minimal toxicity and significant activity of the newly-designed SR compounds, a future optimization of pharmaceutical formulation may develop a promising inhibitor of hyphal formation not only for C. albicans but also for other TUP1- dependent dimorphic fungal infections.},
}
@article {pmid32272186,
year = {2020},
author = {Iwaki, T and Ohshima, T and Tasaki, T and Momoi, Y and Ikawa, S and Kitano, K and Yamamoto, T},
title = {High microbicidal effect of peroxynitric acid on biofilm-infected dentin in a root carious tooth model and verification of tissue safety.},
journal = {Journal of oral biosciences},
volume = {62},
number = {2},
pages = {189-194},
doi = {10.1016/j.job.2020.03.002},
pmid = {32272186},
issn = {1880-3865},
abstract = {OBJECTIVES: Root-caries, which frequently occurs in elderly people, is more difficult to treat than caries in a tooth crown, especially in filling restorations. To overcome this difficulty, it is essential to find a strategy for sufficiently sterilizing the infected dentin; however, techniques for sterilizing carious pathogens inside the biofilm, called dental plaque, have not yet been established. Recently, dental applications of plasma sterilization technology have attracted attention. The mechanism of plasma sterilization became clear, and revealed that peroxynitric acid (PNA) is an effective sterilization substance. Highly concentrated PNA solutions can be chemically synthesized in large quantities without using plasma technology. We thought that the application of PNA solution could be a novel treatment for root caries, and examined the microbicidal effect and safety of PNA.<br><br>METHODS: A sterilization experiment was performed using an extracted tooth model infected with Streptococcus mutans. Subsequently, a biofilm of S. mutans and Candida albicans was formed on a plate or a dentin slice, and sterilization experiments were performed in comparison with chlorhexidine. Furthermore, a toxicity test of PNA was performed using an epithelial tissue model.<br><br>RESULTS: In the infection model, sterilization was achieved with a 22 mM PNA solution in only 10 s. In the biofilm model, a 22 mM PNA solution showed a higher microbicidal effect than 2.0% chlorhexidine. In the toxicity test, 2.0% chlorhexidine was toxic, but a 220 mM PNA solution showed no toxicity.<br><br>CONCLUSIONS: PNA is an unprecedented disinfectant that has high microbicidal activity on biofilm and is safe for tissues.},
}
@article {pmid32269377,
year = {2020},
author = {Tan, D and Hansen, MF and de Carvalho, LN and Røder, HL and Burmølle, M and Middelboe, M and Svenningsen, SL},
title = {High cell densities favor lysogeny: induction of an H20 prophage is repressed by quorum sensing and enhances biofilm formation in Vibrio anguillarum.},
journal = {The ISME journal},
volume = {14},
number = {7},
pages = {1731-1742},
pmid = {32269377},
issn = {1751-7370},
support = {DNRF120//Danmarks Grundforskningsfond (Danish National Research Foundation)/ ; 10098//Villum Fonden (Villum Foundation)/ ; DFF - 7014-00080//Det Frie Forskningsråd (Danish Council for Independent Research)/ ; },
abstract = {Temperate ϕH20-like phages are repeatedly identified at geographically distinct areas as free phage particles or as prophages of the fish pathogen Vibrio anguillarum. We studied mutants of a lysogenic isolate of V. anguillarum locked in the quorum-sensing regulatory modes of low (ΔvanT) and high (ΔvanO) cell densities by in-frame deletion of key regulators of the quorum-sensing pathway. Remarkably, we find that induction of the H20-like prophage is controlled by the quorum-sensing state of the host, with an eightfold increase in phage particles per cell in high-cell-density cultures of the quorum-sensing-deficient ΔvanT mutant. Comparative studies with prophage-free strains show that biofilm formation is promoted at low cell density and that the H20-like prophage stimulates this behavior. In contrast, the high-cell-density state is associated with reduced prophage induction, increased proteolytic activity, and repression of biofilm. The proteolytic activity may dually function to disperse the biofilm and as a quorum-sensing-mediated antiphage strategy. We demonstrate an intertwined regulation of phage-host interactions and biofilm formation, which is orchestrated by host quorum-sensing signaling, suggesting that increased lysogeny at high cell density is not solely a strategy for phages to piggy-back the successful bacterial hosts but is also a host strategy evolved to take control of the lysis-lysogeny switch to promote host fitness.},
}
@article {pmid32268566,
year = {2020},
author = {Fontecha-Umaña, F and Ríos-Castillo, AG and Ripolles-Avila, C and Rodríguez-Jerez, JJ},
title = {Antimicrobial Activity and Prevention of Bacterial Biofilm Formation of Silver and Zinc Oxide Nanoparticle-Containing Polyester Surfaces at Various Concentrations for Use.},
journal = {Foods (Basel, Switzerland)},
volume = {9},
number = {4},
pages = {},
pmid = {32268566},
issn = {2304-8158},
support = {RTI2018-098267-R-C32//Ministerio de Ciencia, Innovación y Universidades/ ; },
abstract = {Food contact surfaces are primary sources of bacterial contamination in food industry processes. With the objective of preventing bacterial adhesion and biofilm formation on surfaces, this study evaluated the antimicrobial activity of silver (Ag-NPs) and zinc oxide (ZnO-NPs) nanoparticle-containing polyester surfaces (concentration range from 400 ppm to 850 ppm) using two kinds of bacteria, Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli), and the prevention of bacterial biofilm formation using the pathogen Listeria monocytogenes. The results of antimicrobial efficacy (reductions ≥ 2 log CFU/cm2) showed that at a concentration of 850 ppm, ZnO-NPs were effective against only E. coli (2.07 log CFU/cm2). However, a concentration of 400 ppm of Ag-NPs was effective against E. coli (4.90 log CFU/cm2) and S. aureus (3.84 log CFU/cm2). Furthermore, a combined concentration of 850 ppm Ag-NPs and 400 ppm ZnO-NPs showed high antimicrobial efficacy against E. coli (5.80 log CFU/cm2) and S. aureus (4.11 log CFU/cm2). The results also showed a high correlation between concentration levels and the bacterial activity of Ag-ZnO-NPs (R2 = 0.97 for S. aureus, and R2 = 0.99 for E. coli). They also showed that unlike individual action, the joint action of Ag-NPs and ZnO-NPs has high antimicrobial efficacy for both types of microorganisms. Moreover, Ag-NPs prevent the biofilm formation of L. monocytogenes in humid conditions of growth at concentrations of 500 ppm. Additional studies under different conditions are needed to test the durability of nanoparticle containing polyester surfaces with antimicrobial properties to optimize their use.},
}
@article {pmid32267888,
year = {2020},
author = {Karbysheva, S and Di Luca, M and Butini, ME and Winkler, T and Schütz, M and Trampuz, A},
title = {Comparison of sonication with chemical biofilm dislodgement methods using chelating and reducing agents: Implications for the microbiological diagnosis of implant associated infection.},
journal = {PloS one},
volume = {15},
number = {4},
pages = {e0231389},
pmid = {32267888},
issn = {1932-6203},
abstract = {The diagnosis of implant-associated infections is hampered due to microbial adherence and biofilm formation on the implant surface. Sonication of explanted devices was shown to improve the microbiological diagnosis by physical removal of biofilms. Recently, chemical agents have been investigated for biofilm dislodgement such as the chelating agent ethylenediaminetetraacetic acid (EDTA) and the reducing agent dithiothreitol (DTT). We compared the activity of chemical methods for biofilm dislodgement to sonication in an established in vitro model of artificial biofilm. Biofilm-producing laboratory strains of Staphylococcus epidermidis (ATCC 35984), S. aureus (ATCC 43300), E. coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 53278) were used. After 3 days of biofilm formation, porous glass beads were exposed to control (0.9% NaCl), sonication or chemical agents. Quantitative and qualitative biofilm analyses were performed by colony counting, isothermal microcalorimetry and scanning electron microscopy. Recovered colony counts after treatment with EDTA and DTT were similar to those after exposure to 0.9% NaCl for biofilms of S. epidermidis (6.3 and 6.1 vs. 6.0 log10 CFU/mL, S. aureus (6.4 and 6.3 vs. 6.3 log10 CFU/mL), E. coli (5.2 and 5.1 vs. 5.1 log10 CFU/mL and P. aeruginosa (5.1 and 5.2 vs. 5.0 log10 CFU/mL, respectively). In contrast, with sonication higher CFU counts were detected with all tested microorganisms (7.5, 7.3, 6.2 and 6.5 log10 CFU/mL, respectively) (p <0.05). Concordant results were observed with isothermal microcalorimetry and scanning electron microscopy. In conclusion, sonication is superior to both tested chemical methods (EDTA and DTT) for dislodgement of S. epidermidis, S. aureus, E. coli and P. aeruginosa biofilms. Future studies may evaluate potential additive effect of chemical dislodgement to sonication.},
}
@article {pmid32266235,
year = {2020},
author = {McGivney, E and Cederholm, L and Barth, A and Hakkarainen, M and Hamacher-Barth, E and Ogonowski, M and Gorokhova, E},
title = {Rapid Physicochemical Changes in Microplastic Induced by Biofilm Formation.},
journal = {Frontiers in bioengineering and biotechnology},
volume = {8},
number = {},
pages = {205},
pmid = {32266235},
issn = {2296-4185},
abstract = {Risk assessment of microplastic (MP) pollution requires understanding biodegradation processes and related changes in polymer properties. In the environment, there are two-way interactions between the MP properties and biofilm communities: (i) microorganisms may prefer some surfaces, and (ii) MP surface properties change during the colonization and weathering. In a 2-week experiment, we studied these interactions using three model plastic beads (polyethylene [PE], polypropylene [PP], and polystyrene [PS]) exposed to ambient bacterioplankton assemblage from the Baltic Sea; the control beads were exposed to bacteria-free water. For each polymer, the physicochemical properties (compression, crystallinity, surface chemistry, hydrophobicity, and surface topography) were compared before and after exposure under controlled laboratory conditions. Furthermore, we characterized the bacterial communities on the MP surfaces using 16S rRNA gene sequencing and correlated community diversity to the physicochemical properties of the MP. Significant changes in PE crystallinity, PP stiffness, and PS maximum compression were observed as a result of exposure to bacteria. Moreover, there were significant correlations between bacterial diversity and some physicochemical characteristics (crystallinity, stiffness, and surface roughness). These changes coincided with variation in the relative abundance of unique OTUs, mostly related to the PE samples having significantly higher contribution of Sphingobium, Novosphingobium, and uncultured Planctomycetaceae compared to the other test materials, whereas PP and PS samples had significantly higher abundance of Sphingobacteriales and Alphaproteobacteria, indicating possible involvement of these taxa in the initial biodegradation steps. Our findings demonstrate measurable signs of MP weathering under short-term exposure to environmentally relevant microbial communities at conditions resembling those in the water column. A systematic approach for the characterization of the biodegrading capacity in different systems will improve the risk assessment of plastic litter in aquatic environments.},
}
@article {pmid32260576,
year = {2020},
author = {Shafeeq, S and Wang, X and Lünsdorf, H and Brauner, A and Römling, U},
title = {Draft Genome Sequence of the Urinary Catheter Isolate Enterobacter ludwigii CEB04 with High Biofilm Forming Capacity.},
journal = {Microorganisms},
volume = {8},
number = {4},
pages = {},
pmid = {32260576},
issn = {2076-2607},
support = {634588.//Horizon 2020 Framework Programme/ ; },
abstract = {:Enterobacter ludwigii is a fermentative Gram-negative environmental species and accidental human pathogen that belongs to the Enterobacter cloacae complex with the general characteristics of the genus Enterobacter. The clinical isolate E. ludwigii CEB04 was derived from a urinary tract catheter of an individual not suffering from catheter-associated urinary tract infection. The draft genome sequence of the high biofilm forming E. ludwigii CEB04 was determined by PacBio sequencing. The chromosome of E. ludwigii CEB04 is comprised of one contig of 4,892,375 bps containing 4596 predicted protein-coding genes and 120 noncoding RNAs. E. ludwigii CEB04 harbors several antimicrobial resistance markers and has an extended cyclic-di-GMP signaling network compared to Escherichia coli K-12.},
}
@article {pmid32260420,
year = {2020},
author = {Jouneghani, RS and Castro, AHF and Panda, SK and Swennen, R and Luyten, W},
title = {Antimicrobial Activity of Selected Banana Cultivars Against Important Human Pathogens, Including Candida Biofilm.},
journal = {Foods (Basel, Switzerland)},
volume = {9},
number = {4},
pages = {},
pmid = {32260420},
issn = {2304-8158},
abstract = {Ten banana (Musa spp.) cultivars were studied for their antimicrobial properties. Three plant parts (corm, pseudostem and leaves) were collected separately and extracted with different solvents, viz., hexane, acetone, ethanol and water. The 50% inhibitory concentration (IC50) was evaluated using a broth microdilution assay. Eight human bacterial and one fungal pathogen were tested. Acetone and ethanol extract(s) often exhibited significant antimicrobial activity, while hexane extracts were less active. Aqueous extracts often showed microbial growth, possibly by endophytes. Leaf extracts were most active, followed by pseudostem, and corm was least active. All the tested banana cultivars were found to contain antimicrobials, as demonstrated by inhibition of selected human pathogens. However, cultivars such as Dole, Saba, Fougamou, Namwah Khom, Pelipita and Mbwazirume showed a broad-spectrum activity, inhibiting all tested pathogens. Other cultivars such as Petit Naine and Kluai Tiparot showed a narrow-spectrum activity, including antibiofilm activity against Candida albicans. Our results support the use of different parts of banana plants in traditional human medicine for infections, including diarrhea and dysentery, and some sexually transmitted diseases, as well as for packaging spoilable materials like food.},
}
@article {pmid32260416,
year = {2020},
author = {Chen, L and Tang, ZY and Cui, SY and Ma, ZB and Deng, H and Kong, WL and Yang, LW and Lin, C and Xiong, WG and Zeng, ZL},
title = {Biofilm Production Ability, Virulence and Antimicrobial Resistance Genes in Staphylococcus aureus from Various Veterinary Hospitals.},
journal = {Pathogens (Basel, Switzerland)},
volume = {9},
number = {4},
pages = {},
pmid = {32260416},
issn = {2076-0817},
support = {2018YFD0500300//the National Key R&amp;D Program of China/ ; },
abstract = {:Staphylococcus aureus (S. aureus) is one of the most clinically important zoonotic pathogens, but an understanding of the prevalence, biofilm formulation ability, virulence, and antimicrobial resistance genes of S. aureus from veterinary hospitals is lacking. By characterizing S. aureus in different origins of veterinary hospitals in Guangzhou, China, in 2019, we identified with the presence of S. aureus in pets (17.1%), veterinarians (31.7%), airborne dust (19.1%), environmental surfaces (4.3%), and medical device surfaces (10.8%). Multilocus sequence typing (MLST) and Staphylococcus protein A (spa) typing analyses demonstrated methicillin-sensitive S. aureus (MSSA) ST398-t571, MSSA ST188-t189, and methicillin-resistant S. aureus (MRSA) ST59-t437 were the most prevalent lineage. S. aureus with similar pulsed-field gel electrophoresis (PFGE) types distributed widely in different kinds of samples. The crystal violet straining assays revealed 100% (3/3) of MRSA ST59 and 81.8% (9/11) of MSSA ST188 showed strong biofilm formulation ability, whereas other STs (ST1, ST5, ST7, ST15, ST88, ST398, ST3154 and ST5353) showed weak biofilm production ability. Polymerase chain reaction (PCR) confirmed the most prevalent leucocidin, staphylococcal enterotoxins, ica operon, and adhesion genes were lukD-lukE (49.0%), sec-sel (15.7%), icaA-icaB-icaC-icaR (100.0%), and fnbB-cidA-fib-ebps-eno (100.0%), respectively. Our study showed that the isolates with strong biofilm production ability had a higher prevalence in clfA, clfB, fnbA and sdrC genes compared to the isolates with weak biofilm production ability. Furthermore, 2 ST1-MRSA isolates with tst gene and 1 ST88-MSSA isolate with lukS/F-PV gene were detected. In conclusion, the clonal dissemination of S. aureus of different origins in veterinary hospitals may have occurred; the biofilm production capacity of S. aureus is strongly correlated with ST types; some adhesion genes such as clfA, clfB, fnbA,andsdrC may pose an influence on biofilm production ability and the emergence of lukS/F-PV and tst genes in S. aureus from veterinary hospitals should raise our vigilance.},
}
@article {pmid32260245,
year = {2020},
author = {Karkowska-Kuleta, J and Surowiec, M and Gogol, M and Koziel, J and Potempa, B and Potempa, J and Kozik, A and Rapala-Kozik, M},
title = {Peptidylarginine Deiminase of Porphyromonas gingivalis Modulates the Interactions between Candida albicans Biofilm and Human Plasminogen and High-Molecular-Mass Kininogen.},
journal = {International journal of molecular sciences},
volume = {21},
number = {7},
pages = {},
pmid = {32260245},
issn = {1422-0067},
support = {2015/17/B/NZ6/02078//National Science Centre of Poland/ ; },
abstract = {Microorganisms that create mixed-species biofilms in the human oral cavity include, among others, the opportunistic fungus Candida albicans and the key bacterial pathogen in periodontitis, Porphyromonas gingivalis. Both species use arsenals of virulence factors to invade the host organism and evade its immune system including peptidylarginine deiminase that citrullinates microbial and host proteins, altering their function. We assessed the effects of this modification on the interactions between the C. albicans cell surface and human plasminogen and kininogen, key components of plasma proteolytic cascades related to the maintenance of hemostasis and innate immunity. Mass spectrometry was used to identify protein citrullination, and microplate tests to quantify the binding of modified plasminogen and kininogen to C. albicans cells. Competitive radioreceptor assays tested the affinity of citrullinated kinins to their specific cellular receptors. The citrullination of surface-exposed fungal proteins reduced the level of unmodified plasminogen binding but did not affect unmodified kininogen binding. However, the modification of human proteins did not disrupt their adsorption to the unmodified fungal cells. In contrast, the citrullination of kinins exerted a significant impact on their interactions with cellular receptors reducing their affinity and thus affecting the role of kinin peptides in the development of inflammation.},
}
@article {pmid32260180,
year = {2020},
author = {Ramos, LS and Mello, TP and Branquinha, MH and Santos, ALS},
title = {Biofilm Formed by Candida haemulonii Species Complex: Structural Analysis and Extracellular Matrix Composition.},
journal = {Journal of fungi (Basel, Switzerland)},
volume = {6},
number = {2},
pages = {},
doi = {10.3390/jof6020046},
pmid = {32260180},
issn = {2309-608X},
support = {001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; 002//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 003//Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro/ ; },
abstract = {Candida haemulonii species complex (C. haemulonii, C. duobushaemulonii, and C. haemulonii var. vulnera) has emerged as opportunistic, multidrug-resistant yeasts able to cause fungemia. Previously, we showed that C. haemulonii complex formed biofilm on polystyrene. Biofilm is a well-known virulence attribute of Candida spp. directly associated with drug resistance. In the present study, the architecture and the main extracellular matrix (ECM) components forming the biofilm over polystyrene were investigated in clinical isolates of the C. haemulonii complex. We also evaluated the ability of these fungi to form biofilm on catheters used in medical arena. The results revealed that all fungi formed biofilms on polystyrene after 48 h at 37 °C. Microscopic analyses demonstrated a dense network of yeasts forming the biofilm structure, with water channels and ECM. Regarding ECM, proteins and carbohydrates were the main components, followed by nucleic acids and sterols. Mature biofilms were also detected on late bladder (siliconized latex), nasoenteric (polyurethane), and nasogastric (polyvinyl chloride) catheters, with the biomasses being significantly greater than on polystyrene. Collectively, our results demonstrated the ability of the C. haemulonii species complex to form biofilm on different types of inert surfaces, which is an incontestable virulence attribute associated with devices-related candidemia in hospitalized individuals.},
}
@article {pmid32259432,
year = {2020},
author = {Liu, G and Zhang, Y and Liu, X and Hammes, F and Liu, WT and Medema, G and Wessels, P and van der Meer, W},
title = {360-Degree Distribution of Biofilm Quantity and Community in an Operational Unchlorinated Drinking Water Distribution Pipe.},
journal = {Environmental science &amp; technology},
volume = {54},
number = {9},
pages = {5619-5628},
pmid = {32259432},
issn = {1520-5851},
abstract = {In the present study, triplicate rings of 360° pipe surfaces of an operational drinking water distribution pipe were swabbed. Each ring was equally divided into 16 parts for swabbing. The collected swabs were grouped into 3 sections and compared with the biofilm samples sampled by sonication of specimens from the same pipe. The results showed that the biofilm is unevenly distributed over the 16 parts and the 3 sections of the pipe surface. Both the active biomass and the number of observed OTUs increased as the measurements proceeded from the top to the bottom of the pipe. The bacterial community was dominated in all sections by Proteobacteria. At the genus level, Nitrospira spp., Terrimonas spp., and Hyphomicrobium spp. were dominant in all sections. Gaiella spp. and Vicinamibacter spp. dominated in S-I, Blastopirellula spp. and Pirellula spp. dominated in S-II, while Holophaga spp. and Phaeodactylibacter spp. dominated in S-III. When swabbing and pipe specimen sonication were compared, the results showed that the sampling strategy significantly influences the obtained biofilm bacterial community. A consistent multisectional swabbing strategy is proposed for future biofilm sampling; it involves collecting swabs from all sections and comparing the swabs from the same position/section across locations.},
}
@article {pmid32259408,
year = {2020},
author = {Contreras-Guerrero, P and Ortiz-Magdaleno, M and Urcuyo-Alvarado, MS and Cepeda-Bravo, JA and Leyva-Del Rio, D and Pérez-López, JE and Romo-Ramírez, GF and Sánchez-Vargas, LO},
title = {Effect of dental restorative materials surface roughness on the in vitro biofilm formation of Streptococcus mutans biofilm.},
journal = {American journal of dentistry},
volume = {33},
number = {2},
pages = {59-63},
pmid = {32259408},
issn = {0894-8275},
mesh = {Biofilms ; Ceramics ; Computer-Aided Design ; *Dental Materials ; Dental Porcelain ; Materials Testing ; *Streptococcus mutans ; Surface Properties ; },
abstract = {PURPOSE: To evaluate Streptococcus mutans biofilm formation over different restorative dental materials.<br><br>METHODS: Using a bioreactor over 72 hours, four commercially available ceramics were evaluated: IPS E-max Press, IPS E-max CAD, Lava Ultimate CAD-CAM, Vita Enamic and two resin composites (SR Nexco Paste and Brilliant NG). The results were evaluated using atomic force microscopy and confocal microscopy, the biofilm was stained and the arbitrary fluorescence units (AFU) quantified.<br><br>RESULTS: The results showed that IPS E-max CAD had the lowest roughness values (4.29±1.79 nm), while the highest values were observed for Vita Enamic discs ((77.13±17.35 nm). Analysis of S. mutans biofilm formation by AFU revealed lower values for IPS E-max CAD (6.77±1.67 nm); the highest values were found for Lava Ultimate (79.99±22.23 nm). Regarding the composite groups, SR Nexco Paste showed roughness values of 15.07±2.77 nm and lower arbitrary fluorescence units of 30.92±12.01 nm than Brilliant NT. There was a correlation between the surface roughness of ceramics and composite with S. mutans biofilm formation.<br><br>CLINICAL SIGNIFICANCE: The adhesion of oral bacteria to restorative dental materials plays a key role in the success of dental treatment; the surface roughness influences the S. mutans biofilm formation.},
}
@article {pmid32259407,
year = {2020},
author = {Ishizawa, M and Tomiyama, K and Hasegawa, H and Hamada, N and Mukai, Y},
title = {Comprehensive analysis of bacterial flora of a biofilm model in initial caries-inducing environment.},
journal = {American journal of dentistry},
volume = {33},
number = {2},
pages = {55-58},
pmid = {32259407},
issn = {0894-8275},
mesh = {Adult ; Bacteria ; Biofilms ; *Dental Caries ; Humans ; Saliva ; Streptococcus mutans ; Sucrose ; },
abstract = {PURPOSE: To analyze changes in pH and bacterial flora with duration of culture and timing of sugar supply using a polymicrobial biofilm model.<br><br>METHODS: The biofilm was prepared using the method of Exterkate et al. Stimulated saliva from an adult was collected on a glass slide and added to unbuffered McBain medium containing 0.2% sucrose and cultivated under anaerobic conditions for 10 hours. Cultivation continued anaerobically in saliva-free medium refreshed twice daily, with or without sucrose, in five groups: in the Control and Groups A and C, with 0.2% sucrose for 96, 192 and 288 hours, respectively; in Groups B and E, with 0.2% sucrose for 96 hours then, respectively, without for 96 and 192 hours; in Group D, with 0.2% sucrose for 96 hours, without for 96 hours, then with for 96 hours. The pH of all spent medium was measured. Total bacteria counts were determined by Q-PCR. The bacterial composition was determined by next-generation sequencing of 16S rDNA.<br><br>RESULTS: The pH of spent medium depended on the presence or absence of sucrose. Total bacteria counts were higher in A, C and D than the other groups, and markedly lower in Group E. Principal components analysis and cluster analysis showed wider variation of bacterial flora of the biofilm in Groups B, D and E than other groups.<br><br>CLINICAL SIGNIFICANCE: Inspection of bacterial flora of a biofilm model of the initial caries-inducing environment may lead to the development of materials and procedures for the prevention of dental caries.},
}
@article {pmid32257646,
year = {2020},
author = {Li, W and Xue, M and Yu, L and Qi, K and Ni, J and Chen, X and Deng, R and Shang, F and Xue, T},
title = {QseBC is involved in the biofilm formation and antibiotic resistance in Escherichia coli isolated from bovine mastitis.},
journal = {PeerJ},
volume = {8},
number = {},
pages = {e8833},
pmid = {32257646},
issn = {2167-8359},
abstract = {Background: Mastitis is one of the most common infectious diseases in dairy cattle and causes significant financial losses in the dairy industry worldwide. Antibiotic therapy has been used as the most effective strategy for clinical mastitis treatment. However, due to the extensive use of antibacterial agents, antimicrobial resistance (AMR) is considered to be one of the reasons for low cure rates in bovine mastitis. In addition, biofilms could protect bacteria by restricting antibiotic access and shielding the bacterial pathogen from mammary gland immune defences. The functional mechanisms of quorum sensing E. coli regulators B an d C (QseBC) have been well studied in E. coli model strains; however, whether QseBC regulates antibiotic susceptibility and biofilm formation in clinical E. coli strain has not been reported.<br><br>Methods: In this study, we performed construction of the qseBC gene mutant, complementation of the qseBC mutant, antimicrobial susceptibility testing, antibacterial activity assays, biofilm formation assays, real-time reverse transcription PCR (RT-PCR) experiments and electrophoretic mobility shift assays (EMSAs) to investigate the role of qseBC in regulating biofilm formation and antibiotic susceptibility in the clinical E. coli strain ECDCM2.<br><br>Results: We reported that inactivation of QseBC led to a decrease in biofilm formation capacity and an increase in antibiotic susceptibility of an E. coli strain isolated from a dairy cow that suffered from mastitis. In addition, this study indicated that QseBC increased biofilm formation by upregulating the transcription of the biofilm-associated genes bcsA, csgA, fliC, motA, wcaF and fimA and decreased antibiotic susceptibility by upregulating the transcription of the efflux-pump-associated genes marA, acrA, acrB, acrD, emrD and mdtH. We also performed EMSA assays, and the results showed that QseB can directly bind to the marA promoter.<br><br>Conclusions: The QseBC two-component system affects antibiotic sensitivity by regulating the transcription of efflux-pump-associated genes. Further, biofilm-formation-associated genes were also regulated by QseBC TCS in E. coli ECDCM2. Hence, this study might provide new clues to the prevention and treatment of infections caused by the clinical E. coli strains.},
}
@article {pmid32256460,
year = {2020},
author = {Khoury, ZH and Vila, T and Puthran, TR and Sultan, AS and Montelongo-Jauregui, D and Melo, MAS and Jabra-Rizk, MA},
title = {The Role of Candida albicans Secreted Polysaccharides in Augmenting Streptococcus mutans Adherence and Mixed Biofilm Formation: In vitro and in vivo Studies.},
journal = {Frontiers in microbiology},
volume = {11},
number = {},
pages = {307},
pmid = {32256460},
issn = {1664-302X},
abstract = {The oral cavity is a complex environment harboring diverse microbial species that often co-exist within biofilms formed on oral surfaces. Within a biofilm, inter-species interactions can be synergistic in that the presence of one organism generates a niche for another enhancing colonization. Among these species are the opportunistic fungal pathogen Candida albicans and the bacterial species Streptococcus mutans, the etiologic agents of oral candidiasis and dental caries, respectively. Recent studies have reported enhanced prevalence of C. albicans in children with caries indicating potential clinical implications for this fungal-bacterial interaction. In this study, we aimed to specifically elucidate the role of C. albicans-derived polysaccharide biofilm matrix components in augmenting S. mutans colonization and mixed biofilm formation. Comparative evaluations of single and mixed species biofilms demonstrated significantly enhanced S. mutans retention in mixed biofilms with C. albicans. Further, S. mutans single species biofilms were enhanced upon exogenous supplementation with purified matrix material derived from C. albicans biofilms. Similarly, growth in C. albicans cell-free spent biofilm culture media enhanced S. mutans single species biofilm formation, however, the observed increase in S. mutans biofilms was significantly affected upon enzymatic digestion of polysaccharides in spent media, identifying C. albicans secreted polysaccharides as a key factor in mediating mixed biofilm formation. The enhanced S. mutans biofilms mediated by the various C. albicans effectors was also demonstrated using confocal laser scanning microscopy. Importantly, a clinically relevant mouse model of oral co-infection was adapted to demonstrate the C. albicans-mediated enhanced S. mutans colonization in a host. Analyses of harvested tissue and scanning electron microscopy demonstrated significantly higher S. mutans retention on teeth and tongues of co-infected mice compared to mice infected only with S. mutans. Collectively, the findings from this study strongly indicate that the secretion of polysacharides from C. albicans in the oral environment may impact the development of S. mutans biofilms, ultimately increasing dental caries and, therefore, Candida oral colonization should be considered as a factor in evaluating the risk of caries.},
}
@article {pmid32256266,
year = {2020},
author = {Abdulhaq, N and Nawaz, Z and Zahoor, MA and Siddique, AB},
title = {Association of biofilm formation with multi drug resistance in clinical isolates of Pseudomonas aeruginosa.},
journal = {EXCLI journal},
volume = {19},
number = {},
pages = {201-208},
pmid = {32256266},
issn = {1611-2156},
abstract = {Pseudomonas aeruginosa is considered as foremost cause of hospital acquired infections due to its innate and plasmid mediated resistance to multiple antibiotics making it a multi drug resistant (MDR) pathogen. Biofilm formation is a pathogenic mechanism harbored by this pathogen which further elevates its resistance to antibiotics and host defense system. The aim of the present study was to evaluate the biofilm forming potential and distribution of pslA gene in multi drug resistant Pseudomonas aeruginosa isolates obtained from different clinical samples. A total of 200 different clinical samples were collected after obtaining written consent from the patients. The samples were subjected to isolation and identification of P. aeruginosa by standard microbiological procedures. Confirmation of isolates was done by polymerase chain reaction targeting oprL gene. Kirby Bauer method was performed for detection of MDR isolates. Congo red agar (CRA) test and Microtiter plate assay (MPA) for observing the biofilm forming ability and amplification of pslA gene was also performed on MDR isolates. The results showed that from 200 samples 52 (26 %) were P. aeruginosa and among them 20 (38.46 %) were MDR isolates. The CRA showed 23 (44.23 %) while MPA detected 49 (94.23 %) isolates as biofilm producers while all the MDR isolates showed biofilm formation by MPA method. The pslA gene was detected in all biofilm forming isolates while 90 % in MDR P. aeruginosa. It was concluded that biofilm forming P. aeruginosa are more resistant to tested antibiotics and biofilm formation is strongly associated with presence of pslA gene.},
}
@article {pmid32256169,
year = {2020},
author = {Al-Shabib, NA and Husain, FM and Rehman, MT and Alyousef, AA and Arshad, M and Khan, A and Masood Khan, J and Alam, P and Albalawi, TA and Shahzad, SA and Syed, JB and Al-Ajmi, MF},
title = {Food color 'Azorubine' interferes with quorum sensing regulated functions and obliterates biofilm formed by food associated bacteria: An in vitro and in silico approach.},
journal = {Saudi journal of biological sciences},
volume = {27},
number = {4},
pages = {1080-1090},
pmid = {32256169},
issn = {1319-562X},
abstract = {Quorum sensing (QS) plays a crucial role in different stages of biofilm development, virulence production, and subsequently to the growth of bacteria in food environments. Biofilm mediated spoilage of food is one of the ongoing challenge faced by the food industry worldwide as it incurs substantial economic losses and leads to various health issues. In the present investigation, we studied the interference of quorum sensing, its regulated virulence functions, and biofilm in food-associated bacteria by colorant azorubine. In vitro bioassays demonstrated significant inhibition of QS and its coordinated virulence functions in Chromobacterium violaceum 12472 (violacein) and Pseudomonas aeruginosa PAO1 (elastase, protease, pyocyanin, and alginate). Further, the decrease in the production EPS (49-63%) and swarming motility (61-83%) of the pathogens was also recorded at sub-MICs. Azorubine demonstrated broad-spectrum biofilm inhibitory potency (50-65%) against Chromobacterium violaceum, Pseudomonas aeruginosa, E. coli O157:H7, Serratia marcescens, and Listeria monocytogenes. ROS generation due to the interaction between bacteria and azorubine could be responsible for the biofilm inhibitory action of the food colorant. Findings of the in vitro studies were well supported by molecular docking and simulation analysis of azorubine and QS virulence proteins. Azorubine showed strong binding to PqsA as compared to other virulent proteins (LasR, Vfr, and QscR). Thus, it is concluded that azorubine is a promising candidate to ensure food safety by curbing the menace of bacterial QS and biofilm-based spoilage of food and reduce economic losses.},
}
@article {pmid32255642,
year = {2020},
author = {Arias, SL and Devorkin, J and Civantos, A and Allain, JP},
title = {Escherichia coli Adhesion and Biofilm Formation on Polydimethylsiloxane are Independent of Substrate Stiffness.},
journal = {Langmuir : the ACS journal of surfaces and colloids},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.langmuir.0c00130},
pmid = {32255642},
issn = {1520-5827},
abstract = {Bacterial adhesion and biofilm formation on the surface of biomedical devices are detrimental processes that compromise patient safety and material functionality. Several physicochemical factors are involved in biofilm growth, including the surface properties. Among these, material stiffness has recently been suggested to influence microbial adhesion and biofilm growth in a variety of polymers and hydrogels. However, no clear consensus exists about the role of material stiffness in biofilm initiation and whether very compliant substrates are deleterious to bacterial cell adhesion. Here, by systematically tuning substrate topography and stiffness while keeping the surface free energy of polydimethylsiloxane substrates constant, we show that topographical patterns at the micron and submicron scale impart unique properties to the surface which are independent of the material stiffness. The current work provides a better understanding of the role of material stiffness in bacterial physiology and may constitute a cost-effective and simple strategy to reduce bacterial attachment and biofilm growth even in very compliant and hydrophobic polymers.},
}
@article {pmid32252300,
year = {2020},
author = {Flannery, A and Le Berre, M and Pier, GB and O'Gara, JP and Kilcoyne, M},
title = {Glycomics Microarrays Reveal Differential In Situ Presentation of the Biofilm Polysaccharide Poly-N-acetylglucosamine on Acinetobacter baumannii and Staphylococcus aureus Cell Surfaces.},
journal = {International journal of molecular sciences},
volume = {21},
number = {7},
pages = {},
pmid = {32252300},
issn = {1422-0067},
support = {Postgraduate Scholarship award//Irish Research Council/ ; Analytical Chemistry Trust Fund Fellowship 2018//Royal Society of Chemistry/ ; HRA-POR-2015-1158/HRBI_/Health Research Board/Ireland ; },
abstract = {The biofilm component poly-N-acetylglucosamine (PNAG) is an important virulence determinant in medical-device-related infections caused by ESKAPE group pathogens including Gram-positive Staphylococcus aureus and Gram-negative Acinetobacter baumannii. PNAG presentation on bacterial cell surfaces and its accessibility for host interactions are not fully understood. We employed a lectin microarray to examine PNAG surface presentation and interactions on methicillin-sensitive (MSSA) and methicillin-resistant S. aureus (MRSA) and a clinical A. baumannii isolate. Purified PNAG bound to wheatgerm agglutinin (WGA) and succinylated WGA (sWGA) lectins only. PNAG was the main accessible surface component on MSSA but was relatively inaccessible on the A. baumannii surface, where it modulated the presentation of other surface molecules. Carbohydrate microarrays demonstrated similar specificities of S. aureus and A. baumannii for their most intensely binding carbohydrates, including 3' and 6'sialyllactose, but differences in moderately binding ligands, including blood groups A and B. An N-acetylglucosamine-binding lectin function which binds to PNAG identified on the A. baumannii cell surface may contribute to biofilm structure and PNAG surface presentation on A. baumannii. Overall, these data indicated differences in PNAG presentation and accessibility for interactions on Gram-positive and Gram-negative cell surfaces which may play an important role in biofilm-mediated pathogenesis.},
}
@article {pmid32252278,
year = {2020},
author = {Bissong, MEA and Ateba, CN},
title = {Genotypic and Phenotypic Evaluation of Biofilm Production and Antimicrobial Resistance in Staphylococcus aureus Isolated from Milk, North West Province, South Africa.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {9},
number = {4},
pages = {