@article {pmid31728266,
year = {2019},
author = {Azimi, L and Lari, AR},
title = {Colistin-resistant Pseudomonas aeruginosa clinical strains with defective biofilm formation.},
journal = {GMS hygiene and infection control},
volume = {14},
number = {},
pages = {Doc12},
doi = {10.3205/dgkh000328},
pmid = {31728266},
issn = {2196-5226},
abstract = {Aim: Colistin is the only effective antibiotic in some cases of Pseudomonasaeruginosa resistance to all tested antibiotics, even carbapenem. On the other hand, biofilm formation is one of the antibiotic resistance mechanisms in this bacterium. The aim of this study was to examine biofilm formation in colistin-resistant P. aeruginosa for the first time. Method: Two groups of P. aeruginosa were included in this study: 1) colistin-resistant and 2) colistin-susceptible. Biofilm formation was determined in these groups using the micro-tube test well as PCR to detect the genes involved in biofilm formation (ppk and molA). The plasmids for colistin resistance, mcr-1 and mcr-2, were also determined. P. aeruginosa ATCC 27853 was used as a control for all tests. Results: Strong biofilm formation was observed only in colistin-susceptible strains, and ppk and modA were not detected in colistin-resistant strains. The control strain P. aeruginosa ATCC 27853 possesses ppk and modA and is categorized as a strong biofilm formation group. According to the results of this study, colistin resistance is associated with defective biofilm formation, as reported by other studies on Acinetobacter baumannii.},
}
@article {pmid31728201,
year = {2019},
author = {Penesyan, A and Nagy, SS and Kjelleberg, S and Gillings, MR and Paulsen, IT},
title = {Rapid microevolution of biofilm cells in response to antibiotics.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {34},
doi = {10.1038/s41522-019-0108-3},
pmid = {31728201},
issn = {2055-5008},
abstract = {Infections caused by Acinetobacter baumannii are increasingly antibiotic resistant, generating a significant public health problem. Like many bacteria, A. baumannii adopts a biofilm lifestyle that enhances its antibiotic resistance and environmental resilience. Biofilms represent the predominant mode of microbial life, but research into antibiotic resistance has mainly focused on planktonic cells. We investigated the dynamics of A. baumannii biofilms in the presence of antibiotics. A 3-day exposure of A. baumannii biofilms to sub-inhibitory concentrations of antibiotics had a profound effect, increasing biofilm formation and antibiotic resistance in the majority of biofilm dispersal isolates. Cells dispersing from biofilms were genome sequenced to identify mutations accumulating in their genomes, and network analysis linked these mutations to their phenotypes. Transcriptomics of biofilms confirmed the network analysis results, revealing novel gene functions of relevance to both resistance and biofilm formation. This approach is a rapid and objective tool for investigating resistance dynamics of biofilms.},
}
@article {pmid31727369,
year = {2019},
author = {Katoch, P and Gupta, K and Yennamalli, RM and Vashistt, J and Bisht, GS and Shrivastava, R},
title = {Random insertion transposon mutagenesis of Mycobacterium fortuitum identified mutant defective in biofilm formation.},
journal = {Biochemical and biophysical research communications},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.bbrc.2019.11.021},
pmid = {31727369},
issn = {1090-2104},
abstract = {Mycobacterium fortuitum has emerged as a nosocomial infectious agent and biofilm formation attributed for the presence of this bacterium in hospital environment. Transposon random mutagenesis was used to identify membrane-proteins for biofilm formation in M. fortuitum. Ten mutants were shortlisted from a library of 450 mutants for examine their biofilm forming ability. Comparative biofilm ability with respect to wild type M. fortuitum ATCC 6841 showed an altered and delayed biofilm formation in one mutant namely, MT721. Sequence analysis revealed mutation in anthranilate phosphoribosyl transferase (MftrpD), which is associated with tryptophan operon. Functional interaction study of TrpD protein through STRING showed its interaction with chorismate utilizing proteins, majorly involved in synthesis of aromatic amino acid and folic acid, suggesting that biofilm establishment and maintenance requires components of central metabolism. Our study indicates important role of MftrpD in establishment and maintenance of biofilm by M. fortuitum, which may further be explored for drug discovery studies against mycobacterial infections.},
}
@article {pmid31725203,
year = {2019},
author = {Bernardi, S and Karygianni, L and Filippi, A and Anderson, AC and Zürcher, A and Hellwig, E and Vach, K and Macchiarelli, G and Al-Ahmad, A},
title = {Combining culture and culture-independent methods reveals new microbial composition of halitosis patients' tongue biofilm.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e958},
doi = {10.1002/mbo3.958},
pmid = {31725203},
issn = {2045-8827},
support = {DFG, AL-1179/2-1//German Research foundation/ ; },
abstract = {BACKGROUND: Oral malodor is a very discomforting condition deriving from the presence of volatile sulfur compounds in the expired air. In halitosis of intraoral etiology, the volatile sulfur compounds are metabolic products of the oral microorganisms within the biofilm coating the tongue dorsum as well as other tissues in the oral cavity. The aim of this study was to characterize and compare the microbial composition of tongue biofilm in volunteers suffering from halitosis and healthy volunteers by means of both the culture method and culture-independent cloning technique.<br><br>RESULTS: A high bacterial variety (more than 80 different species) was detected using the combination of both methods. A distinct bacterial composition was revealed in the halitosis-associated biofilms compared with the health-associated biofilms. Actinomyces graevenitzii was shown to be significantly associated with the halitosis condition. The culture method identified 47 species, included Veillonella rogosae, never isolated from the tongue biofilm of halitosis patients so far. In the healthy condition, the culture-dependent method showed that the most frequent species were Streptococcus parasanguinis among the aerobes and Veillonella spp. among the anaerobes. The culture-independent cloning method detected more than 50 species. Streptococci, in particular S. mitis/oralis, S. pseudopneumoniae, and S. infantis as well as Prevotella spp., were found most frequently in halitosis patients. Streptococcus salivarius and Rothia mucilaginosa were found more frequently in the healthy condition.<br><br>CONCLUSIONS: The combination of the culture-dependent and culture-independent cloning techniques allowed for a widespread analysis of the tongue biofilm in halitosis patients. The results can support further pharmacological research for new antimicrobial agents and halitosis therapy strategies.},
}
@article {pmid31722994,
year = {2019},
author = {Oppy, CC and Jebeli, L and Kuba, M and Oates, CV and Strugnell, R and Edgington-Mitchell, LE and Valvano, MA and Hartland, EL and Newton, HJ and Scott, NE},
title = {Loss of O-Linked Protein Glycosylation in Burkholderia cenocepacia Impairs Biofilm Formation and Siderophore Activity and Alters Transcriptional Regulators.},
journal = {mSphere},
volume = {4},
number = {6},
pages = {},
doi = {10.1128/mSphere.00660-19},
pmid = {31722994},
issn = {2379-5042},
abstract = {O-linked protein glycosylation is a conserved feature of the Burkholderia genus. The addition of the trisaccharide β-Gal-(1,3)-α-GalNAc-(1,3)-β-GalNAc to membrane exported proteins in Burkholderia cenocepacia is required for bacterial fitness and resistance to environmental stress. However, the underlying causes of the defects observed in the absence of glycosylation are unclear. Using proteomics, luciferase reporter assays, and DNA cross-linking, we demonstrate the loss of glycosylation leads to changes in transcriptional regulation of multiple proteins, including the repression of the master quorum CepR/I. These proteomic and transcriptional alterations lead to the abolition of biofilm formation and defects in siderophore activity. Surprisingly, the abundance of most of the known glycosylated proteins did not significantly change in the glycosylation-defective mutants, except for BCAL1086 and BCAL2974, which were found in reduced amounts, suggesting they could be degraded. However, the loss of these two proteins was not responsible for driving the proteomic alterations, biofilm formation, or siderophore activity. Together, our results show that loss of glycosylation in B. cenocepacia results in a global cell reprogramming via alteration of the transcriptional regulatory systems, which cannot be explained by the abundance changes in known B. cenocepacia glycoproteins.IMPORTANCE Protein glycosylation is increasingly recognized as a common posttranslational protein modification in bacterial species. Despite this commonality, our understanding of the role of most glycosylation systems in bacterial physiology and pathogenesis is incomplete. In this work, we investigated the effect of the disruption of O-linked glycosylation in the opportunistic pathogen Burkholderia cenocepacia using a combination of proteomic, molecular, and phenotypic assays. We find that in contrast to recent findings on the N-linked glycosylation systems of Campylobacter jejuni, O-linked glycosylation does not appear to play a role in proteome stabilization of most glycoproteins. Our results reveal that loss of glycosylation in B. cenocepacia strains leads to global proteome and transcriptional changes, including the repression of the quorum-sensing regulator cepR (BCAM1868) gene. These alterations lead to dramatic phenotypic changes in glycosylation-null strains, which are paralleled by both global proteomic and transcriptional alterations, which do not appear to directly result from the loss of glycosylation per se. This research unravels the pleiotropic effects of O-linked glycosylation in B. cenocepacia, demonstrating that its loss does not simply affect the stability of the glycoproteome, but also interferes with transcription and the broader proteome.},
}
@article {pmid31721708,
year = {2019},
author = {Khan, F and Nguyen Pham, DT and Oloketuyi, SF and Kim, YM},
title = {Antibiotics and their different application strategies in controlling the biofilm forming pathogenic bacteria.},
journal = {Current pharmaceutical biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.2174/1389201020666191112155905},
pmid = {31721708},
issn = {1873-4316},
abstract = {BACKGROUND: The establishment of biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. Biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of extracellular polymeric substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment.<br><br>METHODS: Up to the present, several methodologies employing antibiotics as an anti-biofilm, anti-virulence or quorum quenching agent have been developed for the biofilm inhibition and eradication of pre-formed matured biofilm.<br><br>RESULTS: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit the biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) the combination of multiple antibiotics, (2) the combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier.<br><br>CONCLUSION: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.},
}
@article {pmid31721122,
year = {2020},
author = {Van Dyck, K and Van Dijck, P and Vande Velde, G},
title = {Bioluminescence Imaging to Study Mature Biofilm Formation by Candida spp. and Antifungal Activity In Vitro and In Vivo.},
journal = {Methods in molecular biology (Clifton, N.J.)},
volume = {2081},
number = {},
pages = {127-143},
doi = {10.1007/978-1-4939-9940-8_9},
pmid = {31721122},
issn = {1940-6029},
abstract = {The widespread use of indwelling medical devices has increased the number of device-related infections in hospitalized patients. These infections are often associated with the formation of biofilms on the medical implants that are difficult to treat because of their resistance to the classical antifungal drugs. The most common fungi isolated from catheters and other medical devices are Candida species. The Candida genus contains multiple species of which C. albicans and C. glabrata are the two most common pathogenic yeasts in humans. A limited number of animal models is available for investigating host-pathogen interactions and testing novel antifungal drugs in vivo against these species. Fungal load in biofilms in these models is traditionally analyzed postmortem, requiring host sacrifice and enumeration of microorganisms from individual biofilms in order to evaluate the amount of colony forming units and the efficacy of antifungal treatment. Bioluminescence imaging (BLI) made compatible with small animal models for in vivo biofilm formation is a valuable tool to follow biofilm development and its treatment longitudinally. Due to the noninvasive nature of BLI, the imaging procedure can be repeated in the same animal, allowing for follow-up of the biofilm growth in vivo without removing the implanted device or detaching the biofilm from its substrate. Although detecting a quantifiable in vivo BLI signal from biofilms formed on the inside of implanted catheters is challenging, BLI proved to be a practical tool in the study of fungal biofilms. This method describes the use of BLI for in vitro and in vivo follow-up of device-related fungal biofilm formation in mice and rats and antifungal activity testing against both C. albicans and C. glabrata device-associated biofilms. It can further be applied for efficient in vivo screening for interesting genes of the pathogen and the host involved in biofilm formation.},
}
@article {pmid31720769,
year = {2019},
author = {Zhang, Y and Zhao, L and Song, T and Cheng, Y and Bao, M and Li, Y},
title = {Simultaneous nitrification and denitrification in an aerobic biofilm biosystem with loofah sponges as carriers for biodegrading hydrolyzed polyacrylamide-containing wastewater.},
journal = {Bioprocess and biosystems engineering},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00449-019-02247-x},
pmid = {31720769},
issn = {1615-7605},
support = {2013AA064401//Major Projects of the National High Technology Research and Development Program 863/ ; 51174181//National Natural Science Foundation of China/ ; 201861016//Fundamental Research Funds for the Central Universities/ ; 2017GSF217012//Key Research and Development Program of Shandong Province (public welfare special project)/ ; },
abstract = {Simultaneous nitrification and denitrification (SND) during treating hydrolyzed polyacrylamide (HPAM) containing wastewater were explored in an aerobic biofilm reactor biosystem. Here, loofah sponges as the environment-friendly and low-cost material were applied as the carriers in this biosystem. The removal efficiencies of HPAM and total nitrogen (TN) reached 43.6% and 54.3%, respectively, after 120 days stabilized running periods. Moreover, the structure of loofah sponges affected anaerobic microenvironment significantly which was indispensable for realizing a high-performance of SND. Key microorganisms in this biosystem included nitrobacteria, denitrobacteria and HPAM-biodegrading bacteria. The abundance of nitrobacteria and denitrobacteria on the biofilm was increased by 17.2% and 15.3%, respectively, through cultivation. Meanwhile, the biotransformation mechanisms of HPAM and diverse valence of nitrogen under different chemical oxygen demand (COD)/N and dissolved oxygen (DO) conditions were investigated. When COD/N and DO were 8:1 and 2 mg/L, HPAM biodegradation, SND efficiency and TN removal achieved their maximum, and the values were 54.3%, 92.3% and 60.1%, respectively. Key enzyme activities also reached their maximum in this condition. The optimal COD/N and DO was pivotal to achieve the high-performance of SND, and it was closely correlated with HPAM biodegradation. Meanwhile, SND could facilitate the biotransformation of HPAM.},
}
@article {pmid31719975,
year = {2019},
author = {Ranjbar, R and Farahani, A},
title = {Study of genetic diversity, biofilm formation, and detection of Carbapenemase, MBL, ESBL, and tetracycline resistance genes in multidrug-resistant Acinetobacter baumannii isolated from burn wound infections in Iran.},
journal = {Antimicrobial resistance and infection control},
volume = {8},
number = {},
pages = {172},
doi = {10.1186/s13756-019-0612-5},
pmid = {31719975},
issn = {2047-2994},
abstract = {Background: Antimicrobial resistance in multidrug-resistant Acinetobacter baumannii (MDR-AB) isolated from burn wound infections is a major concern in intensive care or burns units worldwide, and molecular studies are considered critical strategies for control of MDR-AB outbreaks in this regard. Thus, in this study, antibiotic resistance, biofilm-forming ability, molecular epidemiology of MDR A. baumannii strains recovered from patients with burns were investigated in three major hospital centers of Iran.<br><br>Methods: In this cross-sectional research, 163 non-repetitive A. baumannii strains were tested for susceptibility to antimicrobial agents. Polymerase chain reaction (PCR) was performed to characterize ambler classes A, B, and D β-lactamases, ISAba1 and integrons, biofilm formation was also investigated. Clonal relatedness was analyzed using Pulsed-Field Gel Electrophoresis (PFGE).<br><br>Results: Among 163 A. baumannii strains collected, 94.5% of them were Carbapenem-Non-Susceptible A. baumannii (CNSAB) and also 90.1 and 52.2% of them were Metallo-β-Lactamases (MBL) and Extended-Spectrum β-Lactamases (ESBL) producing isolates, respectively. Colistin and polymyxin B exhibited excellent activity against CNSAB strains. High prevalence of blaOXA - 23-like (85.1%), blaVIM (60.5%), blaPER - 1 (42.3%), tetB (67.8%), and Class 1 integrons (65.6%) were identified in CNSAB strains. ISAba1 element was associated with 42 (25.8%) and 129 (98.5%) of blaOXA-51-like and blaOXA-23-like genes, respectively. 6 clusters with the ability to form strong biofilms were found to be dominant and endemic in our entire areas.<br><br>Conclusions: Results of the present study show that antimicrobial resistance in CNSAB isolates from burn wound infections in monitored hospitals in Iran is multifactorial, and also findings of the study suggested that local antibiotic prescription policies should be regularly reviewed, and efficient infection control measures should be observed. Therefore, further strengthening of surveillance of antimicrobial resistance is urgently needed in these regions.},
}
@article {pmid31719559,
year = {2019},
author = {Horváth, B and Balázs, VL and Varga, A and Böszörményi, A and Kocsis, B and Horváth, G and Széchenyi, A},
title = {Preparation, characterisation and microbiological examination of Pickering nano-emulsions containing essential oils, and their effect on Streptococcus mutans biofilm treatment.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {16611},
doi = {10.1038/s41598-019-52998-6},
pmid = {31719559},
issn = {2045-2322},
abstract = {Essential oils (EOs) are commonly applied in mouth care products like mouthwashes, mostly as an ethanolic solution or by usage of surfactants as solubilising agents. In this study, we present a formulation for preparation of Pickering nano-emulsions (PnE) of EOs as a novel form for application of EOs in mouth care. For the preparation of PnE, we have synthesised surface-modified silica nanoparticles with a mean diameter of 20 nm, as well as we have examined the effect of EOs concentration on PnE droplet size and stability. In vitro study of their effect on the Streptococcus mutans biofilm as the main pathogen of dental health problems has been performed. We have found that EOs in the PnE form has the highest effectiveness against biofilm formation. Diffusion through the biofilm model membrane was studied to explain this observation. We have found that PnEs have a better performance in the transportation of EOs trough model membrane than the ethanolic solutions and conventional emulsions (CEs).},
}
@article {pmid31719234,
year = {2019},
author = {Vaishampayan, A and Grohmann, E},
title = {Multi-resistant biofilm-forming pathogens on the International Space Station.},
journal = {Journal of biosciences},
volume = {44},
number = {5},
pages = {},
pmid = {31719234},
issn = {0973-7138},
abstract = {The International Space Station (ISS) is a confined and closed habitat with unique conditions such as cosmic radiation, and microgravity. These conditions have a strong effect on the human and spacecraft microflora. They can affect the immune response of the crew-members, thus posing a threat to their health. Microbial diversity and abundance of microorganisms from surfaces, air filters and air samples on the ISS have been studied. Enterobacteriaceae, Bacillus spp., Propionibacterium spp., Corynebacterium spp., and Staphylococcus spp. were among the most frequently isolated bacteria. Microbial growth, biofilm formation, stress response, and pathogenicity are affected by microgravity. Increased resistance to antibiotics in bacteria isolated from the ISS has often been reported. Enterococcus faecalis and Staphylococcus spp. isolates from the ISS have been shown to harbor plasmid-encoded transfer genes. These genes facilitate the dissemination of antibiotic resistances. These features of ISS-pathogens call for novel approaches including highly effective antimicrobials which can be easily used on the ISS. A promising material is the antimicrobial surface coating AGXX, a self-recycling material consisting of two noble metals. It drastically reduced microbial growth of multi-resistant human pathogens, such as staphylococci and enterococci. Further novel approaches include the application of cold atmospheric plasma for the sterilization of spacecrafts.},
}
@article {pmid31719231,
year = {2019},
author = {Manobala, T and Shukla, SK and Rao, TS and Kumar, MD},
title = {A new uranium bioremediation approach using radio-tolerant Deinococcus radiodurans biofilm.},
journal = {Journal of biosciences},
volume = {44},
number = {5},
pages = {},
pmid = {31719231},
issn = {0973-7138},
abstract = {Deinococcus radiodurans is the most radiation-tolerant organism ever known. It has gained importance in recent years as a potential candidate for bioremediation of heavy metals, especially the radioactive type. This study investigates the efficiency of a recombinant D. radiodurans (DR1-bf+) strain with an ability to form biofilm for uranium remediation. The modified Arsenazo III dye method was used to estimate the uranium concentration. Uranyl nitrate aqueous solution was generated during the operation of nuclear fuel reprocessing. The D. radiodurans biofilm (DR1-bf+) grown in the presence of 20 mM Ca2+ showed remarkable ability of uranyl ion removal. DR1-bf+ (Ca2+) biofilm removed ~75+/-2% of 1000 mg/L uranium within 30 min post-treatment from uranyl nitrate aqueous solution. Uranium removal rate was also found to be directly proportional to biofilm age. This study discusses the ability of D. radiodurans biofilm in uranium removal.},
}
@article {pmid31719217,
year = {2019},
author = {Karley, D and Shukla, SK and Rao, TS},
title = {Microbiota of spent nuclear fuel pool water with emphasis on their biofilm forming ability on stainless steel (SS-304L).},
journal = {Journal of biosciences},
volume = {44},
number = {5},
pages = {},
pmid = {31719217},
issn = {0973-7138},
abstract = {Spent nuclear fuel (SNF) pool is an essential unit of a nuclear power plant infrastructure, where radioactive fuel rods are kept for cooling and shielding, before reprocessing. This study explored the presence of bacteria in SNF pool water with emphasis on their capability to form biofilms on pool wall cladding material stainless steel (SS-304L). Bacteria were isolated from SNF pool water and were characterized using 16S rRNA gene sequencing. The six bacterial isolates (Bacillus subtilis, Staphylococcus sps., S. arlettae, S. epidermidis, S. auricularis and Chryseobacterium gleum) can grow and form biofilms at very low nutrient condition as well as in chronic radioactivity. The bacterial isolates formed biofilm on SS-304L and glass. However, the biofilm parameters assessed by CLSM microscopy showed that the strains preferred SS-304L surface for biofilm formation. On SS-304L, the maximum biomass (0.45 l μm3/l μm2) was formed by S. arlettae when compared to maximum biomass (0.054 l μm3/l μm2) by Staphylococcus sp., on glass. Maximum biofilm thickness on SS- 304L was observed by Staphylococcus sp. (8.81 l μm) when compared to that of S. epidermidis (4.16 l μm) on the glass surface. The biofilm formation on SS-304L surface suggests the possible risk of microbial-induced corrosion of SNF pool cladding material. This study highlights the need for mandatory monitoring of microbial biofilm formation in an extreme environment such as SNF pool.},
}
@article {pmid31718302,
year = {2019},
author = {Padmavathi, AR and Sriyutha Murthy, P and Das, A and Nishad, PA and Pandian, R and Rao, TS},
title = {Copper oxide nanoparticles as an effective anti-biofilm agent against a copper tolerant marine bacterium, Staphylococcus lentus.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-19},
doi = {10.1080/08927014.2019.1687689},
pmid = {31718302},
issn = {1029-2454},
abstract = {Biofilm formation on antifouling coatings is a serious concern in seawater cooling systems and the maritime industry. A prolific biofilm forming strain (Staphylococcus lentus), possessing high tolerance (>1,000 µg ml-1) to dissolved copper ions (Cu++) was isolated from titanium coupons exposed in the coastal waters of Kalpakkam, east coast of India. S. lentus formed increased biofilm (p < 0.05) at 100 µg ml-1 of Cu++ ions, when compared with the untreated control. To combat biofilm formation of this strain, the efficacy of copper oxide nanoparticles synthesized from copper nitrate by varying the concentrations of hexamine and cetyl trimethyl ammonium bromide (CTAB), was investigated. Complete (100%) inhibition of biofilm formation was observed with plain CuO NP (0.5 M hexamine, uncapped) at 1,000 µg ml-1. Capping with CTAB, influenced the morphology and the purity of the synthesized CuO NPs but did not alter their surface charge. Capping reduced metal ion release from CuO NPs and their antibacterial and anti-biofilm property against S. lentus. Overall, uncapped CuO NPs were effective in controlling biofilm formation of S. lentus. Concurrent release of copper ions and contact mediated physical damage by CuO NPs offer a promising approach to tackle metal tolerant biofilm bacteria.},
}
@article {pmid31717821,
year = {2019},
author = {Najarzadeh, Z and Mohammad-Beigi, H and Nedergaard Pedersen, J and Christiansen, G and Sønderby, TV and Shojaosadati, SA and Morshedi, D and Strømgaard, K and Meisl, G and Sutherland, D and Skov Pedersen, J and Otzen, DE},
title = {Plant Polyphenols Inhibit Functional Amyloid and Biofilm Formation in Pseudomonas Strains by Directing Monomers to Off-Pathway Oligomers.},
journal = {Biomolecules},
volume = {9},
number = {11},
pages = {},
doi = {10.3390/biom9110659},
pmid = {31717821},
issn = {2218-273X},
support = {8021-00208B//Natur og Univers, Det Frie Forskningsråd/ ; 6111-00241B//Teknologi og Produktion, Det Frie Forskningsråd/ ; IG-30702//Tarbiat Modares University/ ; },
abstract = {Self-assembly of proteins to β-sheet rich amyloid fibrils is commonly observed in various neurodegenerative diseases. However, amyloid also occurs in the extracellular matrix of bacterial biofilm, which protects bacteria from environmental stress and antibiotics. Many Pseudomonas strains produce functional amyloid where the main component is the highly fibrillation-prone protein FapC. FapC fibrillation may be inhibited by small molecules such as plant polyphenols, which are already known to inhibit formation of pathogenic amyloid, but the mechanism and biological impact of inhibition is unclear. Here, we elucidate how polyphenols modify the self-assembly of functional amyloid, with particular focus on epigallocatechin gallate (EGCG), penta-O-galloyl-β-d-glucose (PGG), baicalein, oleuropein, and procyanidin B2. We find EGCG and PGG to be the best inhibitors. These compounds inhibit amyloid formation by redirecting the aggregation of FapC monomers into oligomeric species, which according to small-angle X-ray scattering (SAXS) measurements organize into core-shell complexes of short axis diameters 25-26 nm consisting of ~7 monomers. Using peptide arrays, we identify EGCG-binding sites in FapC's linker regions, C and N-terminal parts, and high amyloidogenic sequences located in the R2 and R3 repeats. We correlate our biophysical observations to biological impact by demonstrating that the extent of amyloid inhibition by the different inhibitors correlated with their ability to reduce biofilm, highlighting the potential of anti-amyloid polyphenols as therapeutic agents against biofilm infections.},
}
@article {pmid31717723,
year = {2019},
author = {Janka, E and Carvajal, D and Wang, S and Bakke, R and Dinamarca, C},
title = {Treatment of Metformin-Containing Wastewater by a Hybrid Vertical Anaerobic Biofilm-Reactor (HyVAB).},
journal = {International journal of environmental research and public health},
volume = {16},
number = {21},
pages = {},
doi = {10.3390/ijerph16214125},
pmid = {31717723},
issn = {1660-4601},
support = {ES527646-1//Norges Forskningsråd/ ; },
abstract = {Several series of batch and continuous experiments were performed to investigate the removal of metformin and other contaminants from two wastewaters: wastewater I (WWI) containing 4 mg/L metformin and wastewater II (WWII) containing 110 g/L butanol. Biomethane potential (BMP) tests on WWII showed 77% of total chemical oxygen demand (tCOD = 110 g/L) degradability, and no apparent inhibition effects were observed. BMP tests on WWI showed an apparent inhibitory effect reflected in lower biogas production with increasing metformin concentration in the wastewater. Continuous flow hybrid vertical anaerobic biofilm (HyVAB®) experiments were consistent with the batch test findings. It was necessary to co-digest WWI (metformin) with WWII (easily degradable organics) to achieve complete metformin removal. After a period of adaptation, WWI and WWII co-digestion achieved up to 98% tCOD removal and 100% metformin removal. Most of the contaminants were removed in the anaerobic section of the HyVAB®, which implies that higher chemical oxygen demand (COD) loads than tested here are possible, given some optimization. The pilot reactor was able to manage organic loads of 11 g COD/d and above 10 mg/L metformin with a removal of 98% and 100% for tCOD and metformin, respectively.},
}
@article {pmid31715659,
year = {2019},
author = {Huang, Z and Wu, L and Li, X and Ma, L and Borriss, R and Gao, X},
title = {Zn(II) suppresses biofilm formation in Bacillus amyloliquefaciens by inactivation of the Mn(II) uptake.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.14859},
pmid = {31715659},
issn = {1462-2920},
abstract = {Biofilms are architecturally complex communities of microbial cells held together by a self-produced extracellular matrix. Considerable research has focused on the environmental signals that trigger or inhibit biofilm formation by affecting cellular signaling pathways; however, response to soil cues in plant-associated Bacillus has remained largely unaddressed. Therefore, we aimed to investigate the effect of Zn(II) ions in biofilm formation of Bacillus amyloliquefaciens FZB42. We demonstrated that biofilm formation of B. amyloliquefaciens FZB42 was abolished by Zn(II) at non-deleterious concentrations. Moreover, Zn(II) blocked matrix exopolysaccharide and TasA accumulations. Furthermore, the presence of Zn(II) suppressed expression of the response regulator Spo0F, but not of sensor histidine kinases KinA-D. Suppression of phosphorelay by excess Zn interferes with sinI induction under biofilm-inducing conditions, leading to repression of transcription of operons epsA-O and tapA-sigW-tasA. Addition of Zn(II) decreased the intracellular Mn(II) level by competing for binding to the solute-binding protein MntA during Mn(II) uptake. These results suggest that the metal ion Zn(II) has a negative effect on biofilm formation in the plant growth promoting and biocontrol bacterium B. amyloliquefaciens FZB42. This article is protected by copyright. All rights reserved.},
}
@article {pmid31715042,
year = {2019},
author = {Peng, J and Kumar, K and Gross, M and Kunetz, T and Wen, Z},
title = {Removal of Total Dissolved Solids (TDS) from Wastewater Using a Revolving Algal Biofilm Reactor.},
journal = {Water environment research : a research publication of the Water Environment Federation},
volume = {},
number = {},
pages = {},
doi = {10.1002/wer.1273},
pmid = {31715042},
issn = {1554-7531},
abstract = {Total dissolved solids (TDS) comprising inorganic salts and organic matters are pollutants of concern to aquatic systems and water for human use. This work aimed to investigate the use of revolving algal biofilm (RAB) reactors as a sustainable and environmental friendly method to remove TDS from industrial effluents and municipal wastewaters. The wastewaters contained chloride, sodium, potassium, calcium, magnesium, and sulfate as the major components. The RAB reactors fed with synthetic industrial effluent with high TDS level demonstrated the best algal growth, with the highest TDS removal efficiency (27%) and removal rate (2,783 mg/L-day and 19,530 mg/m2 -day). A suspended algal culture system only removed 3% TDS from the same wastewater. The TDS removal by the RAB reactors was considered due to several mechanisms such as absorption by the algae cells, adsorption by extracellular polymeric substance (EPS) of the biofilm and/or precipitation. Collectively, this research shows that the RAB reactors can serve as an efficient system in wastewater remediation for TDS removal.},
}
@article {pmid31713778,
year = {2019},
author = {Vaknin, M and Steinberg, D and Featherstone, JD and Feuerstein, O},
title = {Exposure of Streptococcus mutans and Streptococcus sanguinis to blue light in an oral biofilm model.},
journal = {Lasers in medical science},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10103-019-02903-4},
pmid = {31713778},
issn = {1435-604X},
support = {2013445//United States-Israel Binational Science Foundation/ ; 2013445//United States - Israel Binational Science Foundation/ ; },
abstract = {The potential anti-cariogenic effect of blue light was evaluated using an oral biofilm model. Two species, Streptococcus mutans and Streptococcus sanguinis, were cultivated ex vivo on bovine enamel blocks for 24 h, either separately or mixed together, then exposed to blue light (wavelengths 400-500 nm) using 112 J/cm2. Twenty four or 48 h after exposure to light the biofilm structure and biomass were characterized and quantified using SEM and qPCR, respectively. Bacterial viability was analyzed by CLSM using live/dead bacterial staining. Gene expression was examined by RT-qPCR. After exposure to light, S. mutans biomass in mono-species biofilm was increased mainly by dead bacteria, relative to control. However, the bacterial biomass of S. mutans when grown in mixed biofilm and of S. sanguinis in mono-species biofilm was reduced after light exposure, with no significant change in viability when compared to control. Furthermore, when grown separately, an upregulation of gene expression related to biofilm formation of S. mutans, and downregulation of similar genes of S. sanguinis, were measured 24 h after exposure to blue light. However, in mixed biofilm, a downregulation of those genes in both species was observed, although not significant in S. mutans. In conclusion, blue light seems to effectively alter the bacterial biomass by reducing the viability and virulence characteristics in both bacterial species and may promote the anti-cariogenic balance between them, when grown in a mixed biofilm. Therefore, exposure of oral biofilm to blue light has the potential to serve as a complementary approach in preventive dentistry.},
}
@article {pmid31713454,
year = {2019},
author = {Rollin-Pinheiro, R and Rochetti, VP and Dutra da Silva Xisto, MI and Liporagi-Lopes, LC and Bastos, B and Rella, A and Singh, A and Rozental, S and Poeta, MD and Barreto-Bergter, E},
title = {Sphingolipid biosynthetic pathway is crucial for growth, biofilm formation and membrane integrity of Scedosporium boydii.},
journal = {Future medicinal chemistry},
volume = {},
number = {},
pages = {},
doi = {10.4155/fmc-2019-0186},
pmid = {31713454},
issn = {1756-8927},
abstract = {Aim: Glycosphingolipids are conserved lipids displaying a variety of functions in fungal cells, such as determination of cell polarity and virulence. They have been considered as potent targets for new antifungal drugs. The present work aimed to test two inhibitors, myriocin and DL-threo-1-Phenyl-2-palmitoylamino-3-morpholino-1-propanol, in Scedosporium boydii, a pathogenic fungus which causes a wide range of disease. Materials &amp; methods: Mass spectrometry, microscopy and cell biology approaches showed that treatment with both inhibitors led to defects in fungal growth and membrane integrity, and caused an increased susceptibility to the current antifungal agents. Conclusion: These data demonstrate the antifungal potential of drugs inhibiting sphingolipid biosynthesis, as well as the usefulness of sphingolipids as promising targets for the development of new therapeutic options.},
}
@article {pmid31712267,
year = {2019},
author = {Harro, JM and Achermann, Y and Freiberg, JA and Allison, DL and Brao, KJ and Marinos, DP and Sanjari, S and Leid, JG and Shirtliff, ME},
title = {Clearance of Staphylococcus aureus from In Vivo Models of Chronic Infection by Immunization Requires Both Planktonic and Biofilm Antigens.},
journal = {Infection and immunity},
volume = {},
number = {},
pages = {},
doi = {10.1128/IAI.00586-19},
pmid = {31712267},
issn = {1098-5522},
abstract = {Staphylococcus aureus is a causative agent of chronic biofilm-associated infections that are recalcitrant to resolution by the immune system or antibiotics. To combat these infections, an anti-staphylococcal, biofilm-specific quadrivalent vaccine against an osteomyelitis model in rabbits has previously been developed and shown to be effective at eliminating biofilm-embedded bacterial populations. However, the addition of antibiotics was required to eradicate remaining planktonic populations. In this study a planktonic up-regulated antigen was combined with the quadrivalent vaccine to remove the need for antibiotic therapy. Immunization with this pentavalent vaccine followed by intraperitoneal challenge of BALB/c mice with S. aureus resulted in 16.7% versus 91.7% mortality in pentavalent vaccine and control groups, respectively (p<0.001). Complete bacterial elimination was found in 66.7% of the pentavalent cohort, while only 8.3% of the control animals cleared the infection (p<0.05). Further protective efficacy was observed in immunized rabbits following intramedullary challenge with S. aureus, where 62.5% of the pentavalent cohort completely cleared the infection versus none of the control animals (p<0.05). Passive immunization of BALB/c mice with serum IgG against the vaccine antigens prior to intraperitoneal challenge with S. aureus prevented mortality in 100% of mice and eliminated bacteria in 33.3% of the challenged mice. These results demonstrate that targeting both the planktonic and biofilm stages with the pentavalent vaccine or the IgG elicited by immunization can effectively protect against S. aureus infection.},
}
@article {pmid31710602,
year = {2019},
author = {Bridges, AA and Bassler, BL},
title = {The intragenus and interspecies quorum-sensing autoinducers exert distinct control over Vibrio cholerae biofilm formation and dispersal.},
journal = {PLoS biology},
volume = {17},
number = {11},
pages = {e3000429},
doi = {10.1371/journal.pbio.3000429},
pmid = {31710602},
issn = {1545-7885},
abstract = {Vibrio cholerae possesses multiple quorum-sensing (QS) systems that control virulence and biofilm formation among other traits. At low cell densities, when QS autoinducers are absent, V. cholerae forms biofilms. At high cell densities, when autoinducers have accumulated, biofilm formation is repressed, and dispersal occurs. Here, we focus on the roles of two well-characterized QS autoinducers that function in parallel. One autoinducer, called cholerae autoinducer-1 (CAI-1), is used to measure Vibrio abundance, and the other autoinducer, called autoinducer-2 (AI-2), is widely produced by different bacterial species and presumed to enable V. cholerae to assess the total bacterial cell density of the vicinal community. The two V. cholerae autoinducers funnel information into a shared signal relay pathway. This feature of the QS system architecture has made it difficult to understand how specific information can be extracted from each autoinducer, how the autoinducers might drive distinct output behaviors, and, in turn, how the bacteria use QS to distinguish kin from nonkin in bacterial communities. We develop a live-cell biofilm formation and dispersal assay that allows examination of the individual and combined roles of the two autoinducers in controlling V. cholerae behavior. We show that the QS system works as a coincidence detector in which both autoinducers must be present simultaneously for repression of biofilm formation to occur. Within that context, the CAI-1 QS pathway is activated when only a few V. cholerae cells are present, whereas the AI-2 pathway is activated only at much higher cell density. The consequence of this asymmetry is that exogenous sources of AI-2, but not CAI-1, contribute to satisfying the coincidence detector to repress biofilm formation and promote dispersal. We propose that V. cholerae uses CAI-1 to verify that some of its kin are present before committing to the high-cell-density QS mode, but it is, in fact, the broadly made autoinducer AI-2 that sets the pace of the V. cholerae QS program. This first report of unique roles for the different V. cholerae autoinducers suggests that detection of kin fosters a distinct outcome from detection of nonkin.},
}
@article {pmid31710252,
year = {2019},
author = {Rossoni, RD and de Barros, PP and Lopes, LADC and Ribeiro, FC and Nakatsuka, T and Kasaba, H and Junqueira, JC},
title = {Effects of surface pre-reacted glass-ionomer (S-PRG) eluate on Candida spp.: antifungal activity, anti-biofilm properties, and protective effects on Galleria mellonella against C. albicans infection.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-10},
doi = {10.1080/08927014.2019.1686485},
pmid = {31710252},
issn = {1029-2454},
abstract = {Surface pre-reacted glass-ionomer (S-PRG) is a bioactive filler produced by PRG technology, which is applied to various dental materials. The inhibitory effects of S-PRG eluate against Candida, the most common fungal oral pathogen, were investigated. Minimum inhibitory concentrations (MIC) and anti-biofilm activities were tested against Candida albicans, Candida glabrata, Candida krusei, and Candida tropicalis. For the in vivo study, Galleria mellonella was used as a model to evaluate the effects of S-PRG on toxicity, hemocyte counts and candidiasis. The MIC of S-PRG ranged from 5 to 40% (v/v). S-PRG eluate exhibited anti-biofilm activity for all the Candida species tested. Furthermore, injection of S-PRG eluate into G. mellonella was not toxic to the larvae and protected G. mellonella against experimental candidiasis. In addition, S-PRG eluate inhibited biofilm formation by C. albicans, C. glabrata, C. krusei, and C. tropicalis and exerted protective effects on G. mellonella against experimental candidiasis in vivo.},
}
@article {pmid31709555,
year = {2019},
author = {Lange, MD and Farmer, BD and Abernathy, J},
title = {Vertebrate mucus stimulates biofilm development and upregulates iron acquisition genes in Flavobacterium columnare.},
journal = {Journal of fish diseases},
volume = {},
number = {},
pages = {},
doi = {10.1111/jfd.13103},
pmid = {31709555},
issn = {1365-2761},
support = {6010-32000-026-00-D//USDA-ARS Research Project/ ; 6028-32000-007-00-D//USDA-ARS Research Project/ ; },
abstract = {Columnaris disease is responsible for substantial losses throughout the production of many freshwater fish species. One of the ways in which the bacterium Flavobacterium columnare is so effective in initiating disease is through the formation of biofilms on fish skin and gills. To further explore the interaction between host factors and bacterial cells, we assayed the ability of vertebrate mucus to enhance F. columnare biofilm development. Different concentrations of catfish, tilapia and pig mucus (5-60 µg/ml) increased biofilm growth at varying degrees among F. columnare isolates. Our data suggest that vertebrate mucus acts as a signalling molecule for the development of F. columnare biofilms; however, there are clear disparities in how individual isolates respond to different mucus fractions to stimulate biofilms. The expression of iron acquisition genes among two genomovar II isolates showed that ferroxidase, TonB receptor and the siderophore synthetase gene were all significantly upregulated among F. columnare biofilms. Interestingly, the siderophore acetyltransferase gene was only shown to be significantly upregulated in one of the genomovar II isolates. This work provides insight into our understanding of the interaction between F. columnare and vertebrate mucus, which likely contributes to the growth of planktonic cells and the transition into biofilms.},
}
@article {pmid31709419,
year = {2019},
author = {Wang, Z and Chen, XM and Ni, BJ and Tang, YN and Zhao, HP},
title = {Model-based assessment of chromate reduction and nitrate effect in a methane-based membrane biofilm reactor.},
journal = {Water research X},
volume = {5},
number = {},
pages = {100037},
doi = {10.1016/j.wroa.2019.100037},
pmid = {31709419},
issn = {2589-9147},
abstract = {Chromate contamination can pose a high risk to both the environment and public health. Previous studies have shown that CH4-based membrane biofilm reactor (MBfR) is a promising method for chromate removal. In this study, we developed a multispecies biofilm model to study chromate reduction and its interaction with nitrate reduction in a CH4-based MBfR. The model-simulated results were consistent with the experimental data reported in the literature. The model showed that the presence of nitrate in the influent promoted the growth of heterotrophs, while suppressing methanotrophs and chromate reducers. Moreover, it indicated that a biofilm thickness of 150 μm and an influent dissolved oxygen concentration of 0.5 mg O2/L could improve the reactor performance by increasing the chromate removal efficiency under the simulated conditions.},
}
@article {pmid31708908,
year = {2019},
author = {She, P and Zhou, L and Li, S and Liu, Y and Xu, L and Chen, L and Luo, Z and Wu, Y},
title = {Synergistic Microbicidal Effect of Auranofin and Antibiotics Against Planktonic and Biofilm-Encased S. aureus and E. faecalis.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2453},
doi = {10.3389/fmicb.2019.02453},
pmid = {31708908},
issn = {1664-302X},
abstract = {Methicillin-resistant/susceptible Staphylococcus aureus (MRSA/MSSA) and Enterococcus faecalis strains are often found in community- and hospital-acquired infections. The single use of conventional antibiotics hardly completely kills the bacterial cells of interest, especially in the form of biofilms. Thus, drug repurposing and antimicrobial combination are promising ways to solve this problem. Antimicrobial susceptibility assays against cocci in a suspension and in a biofilm mode of growth were performed with broth microdilution methods. Checkerboard assays and the cutaneous mouse infection model were used to examine the activity of auranofin and conventional antibiotics alone and in combination. In the present study, auranofin possesses potent antimicrobial activities against both planktonic cells and biofilms with minimum inhibitory concentrations ranging 0.125-0.5 mg/L. Auranofin in combination with linezolid or fosfomycin showed synergistic antimicrobial activities against S. aureus MSSA and MRSA both in vitro and in vivo. Similarly, auranofin also behaved synergistic effect with chloramphenicol against E. faecalis. Additionally, auranofin improved the antibiofilm efficacy of chloramphenicol and linezolid, even on the biofilms grown on a catheter surface. Though, S. epidermidis showed significant susceptibility to AF treatment, no synergistic antimicrobial effects were observed with antibiotics we tested. In all, the use of a combination of auranofin with linezolid, fosfomycin, and chloramphenicol can provide a synergistic microbicidal effect in vitro and in vivo, which rapidly enhances antimicrobial activity and may help prevent or delay the emergence of resistance.},
}
@article {pmid31708905,
year = {2019},
author = {Millen, S and Gross, C and Donhauser, N and Mann, MC and Péloponèse, JM and Thoma-Kress, AK},
title = {Collagen IV (COL4A1, COL4A2), a Component of the Viral Biofilm, Is Induced by the HTLV-1 Oncoprotein Tax and Impacts Virus Transmission.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2439},
doi = {10.3389/fmicb.2019.02439},
pmid = {31708905},
issn = {1664-302X},
abstract = {Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent for Adult T-Cell Leukemia/Lymphoma (ATLL) and HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP). HTLV-1 infects CD4+ T-cells via cell-to-cell transmission requiring reorganization of the cytoskeleton and expression of the viral transactivator and oncoprotein Tax. Viruses spread at the virological synapse (VS), a virus-induced specialized cell-cell contact, by polarized budding into synaptic clefts, and by cell surface transfer of viral biofilms (VBs). Since little is known about Tax's role in formation of the VB, we asked which component of the VB is regulated by Tax and important for HTLV-1 transmission. Collagens are not only structural proteins of the extracellular matrix and basal membrane but also represent an important component of the VB. Here, we report that among the collagens known to be present in VBs, COL4 is specifically upregulated in the presence of HTLV-1 infection. Further, we found that transient expression of Tax is sufficient to induce COL4A1 and COL4A2 transcripts in Jurkat and CCRF-CEM T-cells, while robust induction of COL4 protein requires continuous Tax expression as shown in Tax-transformed T-cell lines. Repression of Tax led to a significant reduction of COL4A1/A2 transcripts and COL4 protein. Mechanistically, luciferase-based promoter studies indicate that Tax activates the COL4A2 and, to a less extent, the COL4A1 promoter. Imaging showing partial co-localization of COL4 with the viral Gag protein in VBs at the VS and transfer of COL4 and Gag to target cells suggests a role of COL4 in VB formation. Strikingly, in chronically infected C91-PL cells, knockout of COL4A2 impaired Gag transfer between infected T-cells and acceptor T-cells, while release of virus-like particles was unaffected. Taken together, we identified COL4 (COL4A1, COL4A2) as a component of the VB and a novel cellular target of Tax with COL4A2 appearing to impact virus transmission. Thus, this study is the first to provide a link between Tax's activity and VB formation by hijacking COL4 protein functions.},
}
@article {pmid31706910,
year = {2019},
author = {Das, P and Karankar, VS},
title = {New avenues of controlling microbial infections through anti-microbial and anti-biofilm potentials of green mono-and multi-metallic nanoparticles: A review.},
journal = {Journal of microbiological methods},
volume = {},
number = {},
pages = {105766},
doi = {10.1016/j.mimet.2019.105766},
pmid = {31706910},
issn = {1872-8359},
abstract = {Nanoparticles synthesized through the green route deserve special mention because this green technology is not only energy-efficient and cost-effective but also amenable to the environment. Various biological resources have been used for the generation of these 'green nanoparticles'. Biological wastes have also been focused in this direction thereby promoting the value of waste. Reports indicate that green nanoparticles exhibit remarkable antimicrobial activities, both singly as well as in combination with standard antibiotics. The current phenomenon of multi-drug resistance has resulted due to indiscriminate administration of high-doses of antibiotics followed by significant toxicity. In the face of this emergence of drug-resistant microbes, the efficacy of green nanoparticles might prove greatly beneficial. Microbial biofilm is another hurdle in the effective treatment of diseases as the microorganisms, being embedded in the meshwork of the biofilm, evade the antimicrobial agents. Nanoparticles may act as a ray of hope on the face of this challenge too, as they not only destroy the biofilms but also lessen the doses of antibiotics required, when administered in combination with the nanoparticles. It should be further noted that the resistance mechanisms exhibited by the microorganisms seem not that relevant for nanoparticles. The current review, to the best of our knowledge, focuses on the structures of these green nanoparticles along with their biomedical potentials. It is interesting to note how a variety of structures are generated by using resources like microbes or plants or plant products and how the structure affects their activities. This study might pave the way for further development in this arena and future work may be taken up in identifying the detailed mechanism by which 'green' synthesis empowers nanoparticles to kill pathogenic microbes.},
}
@article {pmid31706760,
year = {2019},
author = {Lawrence, JR and Paule, A and Swerhone, GDW and Roy, J and Grigoryan, AA and Dynes, JJ and Chekabab, SM and Korber, DR},
title = {Microscale and molecular analyses of river biofilm communities treated with microgram levels of cerium oxide nanoparticles indicate limited but significant effects.},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {},
number = {},
pages = {113515},
doi = {10.1016/j.envpol.2019.113515},
pmid = {31706760},
issn = {1873-6424},
abstract = {Cerium oxide (CeO2) nanoparticles are used as in-fuel catalysts and in manufacturing processes, creating a potential for release to aquatic environments. Exposures at 1 and 10 μg/L CeO2-nanoparticles were made to assess effects during the development of river biofilm communities. Scanning transmission x-ray microscopy (STXM) indicated extensive sorption of nanoparticles to the community and co-localization with lipid moieties. Following 8 weeks of development, polycarbonate coupons were removed from the reactors and used for molecular analyses, denaturing gradient gel electrophoresis analysis (DGGE-16S rRNA) and 16S rRNA amplicon sequencing. Microscopic imaging of the biofilm communities (bacterial, photosynthetic biomass, exopolymer composition, thickness, protozoan numbers), as well as carbon substrate utilization fingerprinting was performed. There was a trend toward reduced photosynthetic biomass, but no significant effects of CeO2 exposure were found on photosynthetic and bacterial biomass or biofilm thickness. Sole carbon source utilization analyses indicated increased utilization of 10 carbon sources in the carbohydrate, carboxylic acid and amino acids categories related to CeO2 exposures; however, predominantly, no significant effects (p < 0.05) were detected. Measures of microbial diversity, lectin binding affinities of exopolymeric substances and results of DGGE analyses, indicated significant changes to community composition (p < 0.05) with CeO2 exposure. Increased binding of the lectin Canavalia ensiformis was observed, consistent with changes in bacterial-associated polymers. Whereas, no significant changes were observed in binding to residues associated with algal and cyanobacterial exopolymers. 16S rRNA amplicon sequencing of community DNA indicated changes in diversity and shifts in community composition; however, these did not trend with increasing CeO2 exposure. Counting of protozoans in the biofilm communities indicated no significant effects on this trophic level. Thus, based on biomass and functional measures, CeO2 nanoparticles did not appear to have significant effects; however, there was evidence of selection pressure resulting in significant changes in microbial community composition.},
}
@article {pmid31706043,
year = {2019},
author = {Keren-Paz, A and Kolodkin-Gal, I},
title = {A brick in the wall: Discovering a novel mineral component of the biofilm extracellular matrix.},
journal = {New biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.nbt.2019.11.002},
pmid = {31706043},
issn = {1876-4347},
abstract = {Multicellular bacterial communities, known as biofilms, have been thought to be held together solely by a self-produced organic extracellular matrix (ECM). However, new evidence for a missed mineral constituent of ECM in both Gram-positive and Gram-negative bacterial species, is accumulating. Study of two phylogenetically distinct bacteria, Bacillus subtilis and Mycobacterium smegmatis, identified a novel mechanism crucial for proper biofilm development and architecture - an active, genetically regulated, production of crystalline calcite. The calcite scaffolds stabilize bacterial biofilms, limit penetration of small molecule solutes such as antibiotics and play a conserved role in the assembly of those complex differentiated multicellular communities. Accumulating evidence suggests tight biological regulation of the formation of these functional minerals. This review discusses the recently discovered structural and functional roles of extracellular minerals in biofilms. It is proposed that it is time for a more complete view of the ECM as a complex combination of organic and nonorganic materials, especially in the light of the possible implications for treatment of biofilm infections.},
}
@article {pmid31705932,
year = {2019},
author = {Sood, U and Singh, DN and Hira, P and Lee, JK and Kalia, VC and Lal, R and Shakarad, M},
title = {Rapid and solitary production of mono-rhamnolipid biosurfactant and biofilm inhibiting pyocyanin by a taxonomic outlier Pseudomonas aeruginosa strain CR1.},
journal = {Journal of biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jbiotec.2019.11.004},
pmid = {31705932},
issn = {1873-4863},
abstract = {Biosurfactant - Rhamnolipids (RLs) and antibacterial toxin - pyocyanin (PYO) produced by Pseudomonas aeruginosa strains have great potential for biotechnological applications. Generally, RLs are produced as a mixture of di-rhamnolipids (di-RLs) and mono-rhamnolipids (mono-RLs). Mono-RLs possess superior emulsification and antimicrobial properties and are costlier than di-RLs. In this study, a taxonomic outlier P. aeruginosa strain CR1 isolated from rhizosphere soil was explored for mono-RLs and PYO production. Phylogenetically strain CR1 resembles avirulent outlier P. aeruginosa strain ATCC9027, lacks archetypical virulence genes and harbors unique pathways for the synthesis of solely mono-RLs and PYO. Strain CR1 produced RL biosurfactant which efficiently emulsified hydrocarbons, showed hemolysis and inhibited Bacillus subtilis. At 37 °C, strain CR1 exclusively produced 21.77 g L-1 and 19.22 g L-1 rhamnolipid in glycerol amended Luria Bertani (LB) medium and basal medium amended with rice bran oil, respectively after 54 h growth. Besides RL production was unaffected under varying nitrogen sources. Structural characterization using FTIR, TLC, and LC-MS confirmed that strain CR1 exclusively produced mono-RLs, majorly dominated by Rha-C10-C10, Rha-C10-C8, and CH3-Rha-C12:2-C10:1. The compound was stable over a wide pH range (4-12), salinity (25%) and 100 °C indicating its applicability under harsh environmental conditions. In addition, strain CR1 produced 4.5 µg mL-1 PYO, which could efficiently inhibit biofilm formation by Bacillus species. The environmental outlier strain CR1 can be used for the industrial production of biotechnologically important mono-RLs and PYO.},
}
@article {pmid31705133,
year = {2019},
author = {Marquès, C and Collin, V and Franceschi, C and Charbonnel, N and Chatellier, S and Forestier, C},
title = {Fosfomycin and Staphylococcus aureus: transcriptomic approach to assess effect on biofilm, and fate of unattached cells.},
journal = {The Journal of antibiotics},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41429-019-0256-y},
pmid = {31705133},
issn = {1881-1469},
abstract = {Interest has been rekindled in the old antibiotic fosfomycin, partly because of its ability to penetrate biofilm. Using a transcriptomic approach, we investigated the modifications induced by fosfomycin in sessile cells of a clinical Staphylococcus aureus isolated from a device-associated infection. Cells still able to form biofilm after 4 h of incubation in the presence of subinhibitory concentrations of fosfomycin and cells from 24-h-old biofilm later submitted to fosfomycin had 6.77% and 9.41%, respectively, of differentially expressed genes compared with their antibiotic-free control. Fosfomycin induced mostly downregulation of genes assigned to nucleotide, amino acid and carbohydrate transport, and metabolism. Adhesins and capsular biosynthesis proteins encoding genes were downregulated in fosfomycin-grown biofilm, whereas the murein hydrolase regulator lgrA and a D-lactate dehydrogenase-encoding gene were upregulated. In fosfomycin-treated biofilm, the expression of genes encoding adhesins, the cell wall biosynthesis protein ScdA, and to a lesser extent the fosfomycin target MurA was also decreased. Unattached cells surrounding fosfomycin-grown biofilm showed greater ability to form aggregates than their counterparts obtained without fosfomycin. Reducing their global metabolism and lowering cell wall turnover would allow some S. aureus cells to grow in biofilm despite fosfomycin stress while promoting hyperadherent phenotype in the vicinity of the fosfomycin-treated biofilm.},
}
@article {pmid31704413,
year = {2019},
author = {Rehman, ZU and Fortunato, L and Cheng, T and Leiknes, T},
title = {Metagenomic analysis of sludge and early-stage biofilm communities of a submerged membrane bioreactor.},
journal = {The Science of the total environment},
volume = {701},
number = {},
pages = {134682},
doi = {10.1016/j.scitotenv.2019.134682},
pmid = {31704413},
issn = {1879-1026},
abstract = {Biofilm formation on membranes in activated sludge membrane bioreactors (MBR), commonly identified as biofouling, is a significant problem for MBR operations. A better understanding of microbial species involved in the biofilm formation is needed to develop anti-biofilm measures. A read-based and genome-resolved shotgun metagenomic approach was applied to characterize the composition and functional potential of the sludge and early stage biofilm microbial communities in an MBR process. Read-based analysis revealed that the prevalence of different phyla are relatively similar in both the sludge and biofilm samples, with Proteobacteria as the most dominant, followed by Chloroflexi, Bacteroidetes and Planctomycetes. However, the relative abundance of these phyla slightly varies between the sludge and biofilm. Phyla such as Actinobacteria, bacterial candidate phyla, Chlamydiae, Cyanobacteria/Melainabacteria and Firmicutes are 2 to 4 times more abundant in the biofilm than in the sludge. At the genus level, genera belonging to Proteobacteria (Legionella, Caulobacter, Sphingomonas, Acinetobacter and Rhizobium), Cyanobacteria (Hassallia), and Spirochaetes (Turneriella) are at least twice more abundant in the biofilm. These genera, especially those belonging to Phylum Proteobacteria, are known to play an important role in the formation of biofilms on surfaces. The Alpha diversity is found slightly higher in the biofilm, compared with sludge samples. Functional classification of reads through the SEED subsystem shows that functional classes such as those involved in the metabolism of various molecules are significantly different in the biofilm and sludge. A phylogenomic analysis of the six extracted metagenome assembled genomes (MAGs) shows that three MAGs belong to Proteobacteria, and one MAG belong to each of Chloroflexi, Bacteroidetes and Planctomycetes. The relative abundance of the MAG belonging to Alphaproteobacteria is higher in the biofilm. A functional potential analysis of the MAGs reveals their potential to metabolize carbon and nitrogen sources, as well as the prevalence of antibiotic resistance genes.},
}
@article {pmid31703923,
year = {2019},
author = {Alfaifi, AA and Lin, WS and Aldhaian, BA and Levon, JA and Gregory, RL},
title = {Impact of caffeine on metabolic activity and biofilm formation of Candida albicans on acrylic denture resin in the presence of nicotine.},
journal = {The Journal of prosthetic dentistry},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.prosdent.2019.09.007},
pmid = {31703923},
issn = {1097-6841},
abstract = {STATEMENT OF PROBLEM: Candida albicans has been implicated in denture stomatitis, and this effect is exacerbated by nicotine exposure. However, studies have also suggested that caffeine exposure inhibits the growth of C. albicans. The interaction effects of nicotine and caffeine are not yet clear on the growth of C. albicans.<br><br>PURPOSE: The purpose of this in vitro study was to determine the effect of caffeine on metabolic activity and biofilm formation of C. albicans growing on acrylic denture resin while simultaneously exposed to nicotine and, if an effect were to be identified, whether this effect would vary depending on the caffeine concentration.<br><br>MATERIAL AND METHODS: A total of 240 acrylic resin specimens were divided into 2 equal groups (120 each). Specimens in one group were processed to measure C. albicans metabolic activity, and those in the other group were processed to measure C. albicans biofilm attachment. Ten subgroups (n=12) were established within each group with different concentration combinations of nicotine and caffeine to test the interaction effect. The first subgroup was designed as a negative control, containing 0 mg/mL of nicotine and caffeine. The following subgroups all contained 8.00 mg/mL of nicotine, and the caffeine concentrations were prepared at the following 9 levels: 0, 0.25, 0.50, 1.00, 2.00, 4.00, 8.00, 16.00, and 32.00 mg/mL. Metabolic activity was measured by using a 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-carboxanilide (XTT) assay. Biofilm attachment was measured by using spiral plating and calculated in terms of the number of colony-forming units (CFUs)/mL. Descriptive statistics and a 2-way ANOVA were conducted to determine whether the concentrations of nicotine and caffeine used affected the biofilm attachment and metabolic activity of C. albicans (α=.05).<br><br>RESULTS: The presence of 8 mg/mL of nicotine increased the metabolic activity and biofilm formation of C. albicans. When compared with the 0 mg/mL of caffeine and 8.00 mg/mL of nicotine group, caffeine from 1.00 to 4.00 mg/mL significantly increased C. albicans biofilm metabolic activity. Caffeine at 16.00 and 32.00 mg/mL significantly decreased C. albicans biofilm metabolic activity in the presence of 8 mg/mL of nicotine. Caffeine from 1.00 to 32.00 mg/mL significantly decreased the biofilm formation of C. albicans in the presence of 8 mg/mL of nicotine.<br><br>CONCLUSIONS: The presence of 8 mg/mL of nicotine alone increased the metabolic activity and biofilm formation of C. albicans. In the presence of 8 mg/mL of nicotine with different caffeine concentrations, the results suggest that, overall, caffeine at higher concentrations (16 and 32 mg/mL) inhibited the metabolic activity and biofilm formation of C. albicans on acrylic denture resin most.},
}
@article {pmid31703877,
year = {2020},
author = {Liu, F and Sun, Z and Wang, F and Liu, Y and Zhu, Y and Du, L and Wang, D and Xu, W},
title = {Inhibition of biofilm formation and exopolysaccharide synthesis of Enterococcus faecalis by phenyllactic acid.},
journal = {Food microbiology},
volume = {86},
number = {},
pages = {103344},
doi = {10.1016/j.fm.2019.103344},
pmid = {31703877},
issn = {1095-9998},
abstract = {This study aimed to evaluate the inhibitory activity of phenyllactic acid (PLA) against the biofilm formation of Enterococcus faecalis and to explore its potential molecular mechanism. The MIC value of PLA that inhibited the growth of E. faecalis R612-Z1 in BHI broth was 5 mg/mL. PLAs at subinhibitory concentrations of 1.25 and 2.50 mg/mL were found to inhibit biofilm formation by a crystal violet staining assay. The cell swimming and swarming motilities of E. faecalis were reduced in the presence of PLA. An apparent decrease in the thickness of PLA-treated biofilms was observed through confocal laser scanning microscopy analysis. The exopolysaccharide production in E. faecalis biofilms was inhibited by EPS quantification assay and scanning electron microscopy (SEM). qRT-PCR analyses showed that PLA down-regulated the transcription of Ebp pili genes (ebpABC) and Epa polysaccharide genes (epaABE). PLA inhibited the biofilm formation by interfering with cell mobility and EPS production of E. faecalis. In addition, PLA at concentrations of 10.0 mg/mL can effectively control the bacterial cells in a three-day-old mature biofilm of E. faecalis grown on 24-well flat-bottom polystyrene plates and stainless-steel surfaces. Thus, PLA is potentially an effective agent to control E. faecalis biofilms.},
}
@article {pmid31703870,
year = {2020},
author = {Guo, D and Wang, S and Li, J and Bai, F and Yang, Y and Xu, Y and Liang, S and Xia, X and Wang, X and Shi, C},
title = {The antimicrobial activity of coenzyme Q0 against planktonic and biofilm forms of Cronobacter sakazakii.},
journal = {Food microbiology},
volume = {86},
number = {},
pages = {103337},
doi = {10.1016/j.fm.2019.103337},
pmid = {31703870},
issn = {1095-9998},
abstract = {Coenzyme Q0 (CoQ0) has demonstrated antitumor, anti-inflammatory, and anti-angiogenic activities. Cronobacter sakazakii is an opportunistic foodborne pathogen associated with high mortality in neonates. In this study, the antimicrobial activity and possible antimicrobial mechanism of CoQ0 against C. sakazakii were investigated. Moreover, the inactivation effect of CoQ0 on C. sakazakii in biofilms was also evaluated. The minimum inhibitory concentration (MIC) of CoQ0 against C. sakazakii strains ranged from 0.1 to 0.2 mg/mL. Treatment caused cell membrane dysfunction, as evidenced by cell membrane hyperpolarization, decreased intracellular ATP concentration and cell membrane integrity, and changes in cellular morphology. CoQ0 combined with mild heat treatment (45, 50, or 55 °C) decreased the number of viable non-desiccated and desiccated C. sakazakii cells in a time- and dose-dependent manner in reconstituted infant milk. Furthermore, CoQ0 showed effective inactivation activity against C. sakazakii in biofilms on stainless steel, reducing the number of viable cells and damaging the structure of the biofilm. These findings suggest that CoQ0 has a strong inactivate effect on C. sakazakii and could be used in food production environments to effectively control C. sakazakii and reduce the number of illnesses associated with it.},
}
@article {pmid31703863,
year = {2020},
author = {Li, T and Sun, X and Chen, H and He, B and Mei, Y and Wang, D and Li, J},
title = {Methyl anthranilate: A novel quorum sensing inhibitor and anti-biofilm agent against Aeromonas sobria.},
journal = {Food microbiology},
volume = {86},
number = {},
pages = {103356},
doi = {10.1016/j.fm.2019.103356},
pmid = {31703863},
issn = {1095-9998},
abstract = {Quorum sensing (QS), bacterial cell-to-cell communication, is a gene regulatory mechanism that regulates virulence potential and biofilm formation in many pathogens. Aeromonas sobria, a common aquaculture pathogen, was isolated and identified by our laboratory from the deteriorated turbot, and its potential for virulence factors and biofilm production was regulated by QS system. In view of the interference with QS system, this study was aimed to investigate the effect of methyl anthranilate at sub-Minimum Inhibitory Concentrations (sub-MICs) on QS-regulated phenotypes in A. sobria. The results suggested that 0.5 μL/mL of methyl anthranilate evidently reduced biofilm formation (51.44%), swinging motility (74.86%), swarming motility (71.63%), protease activity (43.08%), and acyl-homoserine lactone (AHL) production. Furthermore, the real-time quantitative PCR (RT-qPCR) and in silico analysis showed that methyl anthranilate might inhibit QS system in A. sobria by interfering with the biosynthesis of AHL, as well as competitively binding with receptor protein. Therefore, our data indicated the feasibility of methyl anthranilate as a promising QS inhibitor and anti-biofilm agent for improving food safety.},
}
@article {pmid31700653,
year = {2019},
author = {Harrison, A and Hardison, RL and Wallace, RM and Fitch, J and Heimlich, DR and Bryan, MO and Dubois, L and John-Williams, LS and Sebra, RP and White, P and Moseley, MA and Thompson, JW and Justice, SS and Mason, KM},
title = {Reprioritization of biofilm metabolism is associated with nutrient adaptation and long-term survival of Haemophilus influenzae.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {33},
doi = {10.1038/s41522-019-0105-6},
pmid = {31700653},
issn = {2055-5008},
abstract = {Nontypeable Haemophilus influenzae (NTHI) is a human-restricted pathogen with an essential requirement for heme-iron acquisition. We previously demonstrated that microevolution of NTHI promotes stationary phase survival in response to transient heme-iron restriction. In this study, we examine the metabolic contributions to biofilm formation using this evolved NTHI strain, RM33. Quantitative analyses identified 29 proteins, 55 transcripts, and 31 metabolites that significantly changed within in vitro biofilms formed by RM33. The synthesis of all enzymes within the tryptophan and glycogen pathways was significantly increased in biofilms formed by RM33 compared with the parental strain. In addition, increases were observed in metabolite transport, adhesin production, and DNA metabolism. Furthermore, we observed pyruvate as a pivotal point in the metabolic pathways associated with changes in cAMP phosphodiesterase activity during biofilm formation. Taken together, changes in central metabolism combined with increased stores of nutrients may serve to counterbalance nutrient sequestration.},
}
@article {pmid31700570,
year = {2019},
author = {Teves, A and Blanco, D and Casaretto, M and Torres, J and Alvarado, D and Jaramillo, DE},
title = {Effectiveness of different disinfection techniques of the root canal in the elimination of a multi-species biofilm.},
journal = {Journal of clinical and experimental dentistry},
volume = {11},
number = {11},
pages = {e978-e983},
doi = {10.4317/jced.56000},
pmid = {31700570},
issn = {1989-5488},
abstract = {Background: The purpose of the study was to evaluate the effectiveness of different root canal disinfection techniques in the elimination of a multi-species biofilm from inside the root canal.<br><br>Material and Methods: Fifty mandibular first premolars were used in the present study, standardized to 11mm of root length, and instrumented with a reciprocation system Reciproc, (VDW GmbH, Munich, Germany) to a #50. Longitudinally sectioned halves of the roots were obtained and washed with NaOCl 4%, EDTA 17% and 5% sodium thiosulfate, and sterilized by autoclaving for 15 minutes at 121°C. A multi-species biofilm broth was developed with three strains of bacteria under laboratory conditions: Enterococcus faecalis ATTC 29212, Eikenella corrodens ATTC 23834, Streptococcus anginosus ATTC 33397. Roots were autoclaved and transferred to the broth for 4 days and then were subjected to either disinfection with sodium hypochlorite 4% and XP-endo Finisher (FKG Dentaire, La Chaux-de-Fonds, Switzerland) or chlorhexidine 2% with and without activation with XP-endo Finisher (FKG Dentaire, La Chaux-de-Fonds, Switzerland).<br><br>Results: The evaluations of the biofilm elimination showed results that indicate that the 4% sodium hypochlorite group with positive pressure irrigation presented significant differences with the group that had irrigation with sodium hypochlorite activated with XP-endo Finisher and the chlorhexidine groups to 2% (P<0.05).<br><br>Conclusions: Chlorhexidine 2% activated with the XP-endo Finisher does not exert elimination or improved cleaning effect on the multi-species biofilm. Activation of sodium hypochlorite 4% improved the elimination of the multi-species biofilm. Key words:Biofilm, multispecies, chlorhexidine, sodium hypochlorite.},
}
@article {pmid31699135,
year = {2019},
author = {Theodora, NA and Dominika, V and Waturangi, DE},
title = {Screening and quantification of anti-quorum sensing and antibiofilm activities of phyllosphere bacteria against biofilm forming bacteria.},
journal = {BMC research notes},
volume = {12},
number = {1},
pages = {732},
doi = {10.1186/s13104-019-4775-1},
pmid = {31699135},
issn = {1756-0500},
support = {Penelitian Dasar 2019//Ristekdikti/ ; },
abstract = {OBJECTIVE: The objectives of this research were to screen anti-quorum sensing activity of phyllosphere bacteria and quantify their antibiofilm activity against biofilm forming bacteria (Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Salmonella typhimurium, Vibrio cholerae, Pseudomonas aeruginosa).<br><br>RESULTS: We found 11 phyllosphere bacteria isolates with potential anti-quorum sensing activity. Most of the crude extracts from phyllosphere bacteria isolates had anti-quorum sensing activity against Chromobacterium violaceum at certain concentration (20 and 10 mg/mL), but not crude extract from isolate JB 7F. Crude extract showed the largest turbid zone (1,27 cm) using isolate JB 14B with concentration of 10 mg/mL and the narrowest turbid zone isolate (1 cm) using JB 18B with concentration of 10 mg/mL. Crude extracts showed various antibiofilm activities against all tested pathogenic bacteria, it showed the highest biofilm inhibition (90%) and destruction activities (76%) against S. aureus.},
}
@article {pmid31698068,
year = {2019},
author = {Nagaraju, VT and Ray, AK and Avunje, S and Kumar T, S and Krishnappa, H and Viswanathan, B and Reddy, MA and Kizhakedath, VK and Patil, PK},
title = {Vibrio harveyi biofilm as immunostimulant candidate for high-health pacific white shrimp, Penaeus vannamei farming.},
journal = {Fish &amp; shellfish immunology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.fsi.2019.11.004},
pmid = {31698068},
issn = {1095-9947},
abstract = {The study was to develop Vibrio harveyi biofilm-based novel microbial product and its oral delivery for high health Penaeus vannamei farming. Yield of bacterial biofilm was optimized on chitin substrate (size: <360, 360-850 and 850-1250 μm; concentration: 0.3, 0.6 and 0.9%) in tryptone soy broth (0.15%). The biofilm was characterized by crystal violet assay, SEM and LSCM imaging; protein profiling by SDS-PAGE and LC-ESI-MS/MS. The immune stimulatory effect of the biofilm in yard experiments was evaluated by relative quantification of immune genes using real-time PCR effect on overall improvement on health status under field trials. The highest biofilm yield (6.13 ± 0.2 × 107 cfu/ml) was obtained at 0.6% of <360 μm chitin substrate. The biofilm formation was stabilized by 96 h of incubation at 30 °C. Protein profiling confirmed expression of six additional proteins (SDS-PAGE) and 11 proteins were differentially expressed (LC-ESI-MS/MS) in biofilm cells over free cells of V. harveyi. Oral administration of the biofilm for 48 h confirmed to enhance expression of antimicrobial peptides, penaeidin, crustin and lysozyme in P. vannamei. Further Oral administration of biofilm for two weeks to P. vannamei (1.8 ± 0.13 g) improved the growth (2.66 ± 0.06 g) and survival (84.44 ± 1.82%) compared to control (2.15 ± 0.03 g; 70.94 ± 0.66%) Nursery trials showed a significant reduction in occurrence of anatomical deformities like antenna cut (12.67 ± 0.66%), rostrum cut (4.66 ± 0.87%), and tail rot (3.33 ± 0.88%), compared to animals fed with normal diet which was 24.33 ± 2.72; 14 ± 1.52 and 10.66 ± 1.45% respectively. In vitro and in vivo studies suggest inactivated biofilm cells of V. harveyi on chitin substrate express additional antigenic proteins and when administered orally through feed at regular intervals stimulates immune response and improve growth, survival and health status of shrimp.},
}
@article {pmid31697722,
year = {2019},
author = {Brunetti, G and Navazio, AS and Giuliani, A and Giordano, A and Proli, EM and Antonelli, G and Raponi, G},
title = {Candida blood stream infections observed between 2011 and 2016 in a large Italian University Hospital: A time-based retrospective analysis on epidemiology, biofilm production, antifungal agents consumption and drug-susceptibility.},
journal = {PloS one},
volume = {14},
number = {11},
pages = {e0224678},
doi = {10.1371/journal.pone.0224678},
pmid = {31697722},
issn = {1932-6203},
abstract = {Candida bloodstream infection (BSI) represents a growing infective problem frequently associated to biofilm production due to the utilization of intravascular devices. Candida species distribution (n = 612 strains), their biofilm production and hospital antifungal drug consumption were evaluated in different wards of a tertiary care academic hospital in Italy during the years 2011-2016. In the considered time window, an increasing number of Candida BSI (p = 0.005) and of biofilm producing strains were observed (p<0.0001). Although C. albicans was the species more frequently isolated in BSI with a major biofilm production, an increased involvement of non-albicans species was reported, particularly of C. parapsilosis that displayed a high frequency in catheter infections, and lower biofilm production compared to C. albicans. Although trends of biofilm production were substantially stable in time, a decreasing biofilm production by C. parapsilosis in the Intensive Care Unit (ICU) was observed (p = 0.0041). Principal component analysis displayed a change in antifungal drugs consumption driven by two mutually independent temporal trends, i.e. voriconazole use in the general medicine wards initially, and fluconazole use mainly in the ICU; these factors explain 68.9% and 25.7% of total variance respectively. Moreover, a significant trend (p = 0.003) in fluconazole use during the whole time period considered emerged, particularly in the ICU (p = 0.017), but also in the general medicine wards (p = 0.03). These trends paralleled with significant increase MIC90 of fluconazole (p = 0.05), particularly for C. parapsilosis in the ICU (p = 0.04), with a general and significant decreased trend of the MIC90 values of caspofungin (p = 0.04), and with significant increased MIC50 values for amphotericin B (p = 0.01) over the study period. In conclusion, drug utilization in our hospital turned out to be a putative influencing factor on the ecology of the species, on the increase in time of the biofilm producing strains and on the Candida antifungal susceptibility profile, thus influencing clinical management.},
}
@article {pmid31697703,
year = {2019},
author = {Booth, WT and Davis, RR and Deora, R and Hollis, T},
title = {Structural mechanism for regulation of DNA binding of BpsR, a Bordetella regulator of biofilm formation, by 6-hydroxynicotinic acid.},
journal = {PloS one},
volume = {14},
number = {11},
pages = {e0223387},
doi = {10.1371/journal.pone.0223387},
pmid = {31697703},
issn = {1932-6203},
abstract = {Bordetella bacteria are respiratory pathogens of humans, birds, and livestock. Bordetella pertussis the causative agent of whopping cough remains a significant health issue. The transcriptional regulator, BpsR, represses a number of Bordetella genes relating to virulence, cell adhesion, cell motility, and nicotinic acid metabolism. DNA binding of BpsR is allosterically regulated by interaction with 6-hydroxynicotinic acid (6HNA), the first product in the nicotinic acid degradation pathway. To understand the mechanism of this regulation, we have determined the crystal structures of BpsR and BpsR in complex with 6HNA. The structures reveal that BpsR binding of 6HNA induces a conformational change in the protein to prevent DNA binding. We have also identified homologs of BpsR in other Gram negative bacteria in which the amino acids involved in recognition of 6HNA are conserved, suggesting a similar mechanism for regulating nicotinic acid degradation.},
}
@article {pmid31695365,
year = {2019},
author = {Habibipour, R and Moradi-Haghgou, L and Farmany, A},
title = {Green synthesis of AgNPs@PPE and its Pseudomonas aeruginosa biofilm formation activity compared to pomegranate peel extract.},
journal = {International journal of nanomedicine},
volume = {14},
number = {},
pages = {6891-6899},
doi = {10.2147/IJN.S209912},
pmid = {31695365},
issn = {1178-2013},
abstract = {Background: Bacteria are able to form biofilm on the biotic and abiotic surfaces which helps to protect themselves from deleterious conditions, predation, desiccation, and exposure to antibacterial substances. About 80% of bacterial infections are caused by those bacteria living in the biofilm. Pseudomonas aeruginosa, a gram-negative, non-fermentative bacillus, and the ubiquitous bacterium is an important opportunistic pathogen notorious for biofilm formation and is remarkably resistant against most antibiotics multiple front-line antibiotics, which significantly contributes to eradication failure. The aim of this paper was to evaluate the anti-biofilm formation activity of Ag@PPEs gainst P. aeruginosa bacteria.<br><br>Methods: An aqueous extract of black pomegranate peel was used for the synthesis of silver nanoparticles (AgNPs@PPE). The characteristics, anti-biofilm formation and cell toxicity of AgNPs@PPE were examined in vitro.<br><br>Results: Absorbance at λmax 372 nm which is related to the surface plasmon resonance, confirms the AgNPs@PPE formation. XRD pattern showed the face-centered qubic (fcc) crystalline structure of AgNPs. TEM images showed that spherical AgNPs size is ranged between 32 and 85 nm. The AgNPs@PPE showed inhibition effect against P. aeruginosa biofilm formation at 0.1 to 0.5 mg/ml concentrations. Cell toxicity assay showed that at 400 µg/ml, AgNPs@PPE were safe without a significant toxicity in L929 cell line.<br><br>Conclusion: These data indicate that co-treatment of PPE and AgNPs@PPE significantly decreased the biofilm formation rate. Furthermore, no significant toxicity of AgNPs@PPE was shown against L929 cell line at 400 µg/ml concentration.},
}
@article {pmid31694193,
year = {2019},
author = {Alonso-Calleja, C and Gómez-Fernández, S and Carballo, J and Capita, R},
title = {Prevalence, Molecular Typing, and Determination of the Biofilm-Forming Ability of Listeria monocytogenes Serotypes from Poultry Meat and Poultry Preparations in Spain.},
journal = {Microorganisms},
volume = {7},
number = {11},
pages = {},
doi = {10.3390/microorganisms7110529},
pmid = {31694193},
issn = {2076-2607},
support = {RTI2018-098267-R-C33//Ministerio de Ciencia, Innovación y Universidades/ ; LE164G18//Consejería de Educación, Junta de Castilla y León/ ; },
abstract = {A study was undertaken of the presence of Listeria monocytogenes in 260 samples of poultry meat obtained from retail outlets in northwestern Spain. L. monocytogenes was detected in 20 samples (7.7%). Twenty strains (one strain per positive sample) were characterized. The strains belonged to 10 serotypes: 1/2a (2 strains), 1/2b (2), 1/2c (2), 3a (1), 3b (2), 3c (2), 4a (2), 4b (4), 4c (1), and 4d (2). Cluster analysis (ribotyping; EcoRI) showed a strong genetic relationship between strains isolated from samples coming from different outlets. Ribotyping permitted some isolates of the same serotype to be differentiated, which points to the possible usefulness of this technique in the epidemiological surveillance of L. monocytogenes. All strains formed biofilm on polystyrene, as shown by confocal laser scanning microscopy. The biovolume (between 621.7 ± 36.0 µm3 and 62,984.0 ± 14,888.2 µm3 in the observational field of 14,161 μm2), percentage of surface coverage (from 2.17 ± 0.84% to 94.43 ± 3.97%), roughness (between 0.399 ± 0.052 and 0.830 ± 0.022), and maximum thickness (between 9.00 ± 0.00 µm and 24.00 ± 14.93 µm) of biofilms varied between strains (p < 0.05). These results expand knowledge of the characteristics of L. monocytogenes isolates from poultry.},
}
@article {pmid31693234,
year = {2019},
author = {Davis, RT and Brown, PD},
title = {spoT-mediated stringent response influences environmental and nutritional stress tolerance, biofilm formation and antimicrobial resistance in Klebsiella pneumoniae.},
journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica},
volume = {},
number = {},
pages = {},
doi = {10.1111/apm.13006},
pmid = {31693234},
issn = {1600-0463},
abstract = {Klebsiella pneumoniae is an important opportunistic pathogen with significant potential for virulence and multidrug resistance. Treatment failure often occurs because the pathogen may couple virulence and drug resistance with the stringent response. This study assessed the role of the spoT gene in environmental and nutritional stress tolerance, exopolysaccharide capsule production and biofilm formation. spoT mutants were constructed using the Lambda Red recombinase technique, and mutant and wild-type (WT) strains were exposed to limiting concentrations of carbon (glucose), phosphate and aminoacid, and environmental stresses of ethanol, salt and heat. Cell viability, capsule production and cell length were assessed as well as the ability to grow biofilm under antibiotic pressure using gentamicin and ceftazidime. spoT mutants were more susceptible to stresses versus WT; the reverse was true for survival during biofilm susceptibility assay (p < 0.05), especially when carbon and phosphate were present. spoT mutants were elongated and lacked a capsule versus WT and non-starved strains. The inability to produce capsule in mutants before and after starvation was likely a general effect of spoT mutation. These data suggest that the spoT-mediated stringent response is important for K. pneumoniae in conditions of nutrient limitation, environmental stress and antimicrobial pressure.},
}
@article {pmid31692081,
year = {2019},
author = {Tomizawa, T and Ishikawa, M and Bello-Irizarry, SN and de Mesy Bentley, KL and Ito, H and Kates, SL and Daiss, JL and Beck, C and Matsuda, S and Schwarz, EM and Nishitani, K},
title = {Biofilm producing Staphylococcus epidermidis (RP62A strain) inhibits osseous integration without osteolysis and histopathology in a murine septic implant model.},
journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society},
volume = {},
number = {},
pages = {},
doi = {10.1002/jor.24512},
pmid = {31692081},
issn = {1554-527X},
abstract = {Despite its presence in orthopaedic infections, Staphylococcus epidermidis's ability to directly induce inflammation and bone destruction is unknown. Thus, we compared a clinical strain of methicillin-resistant biofilm-producing Staphylococcus epidermidis (RP62A) to a highly virulent and osteolytic strain of methicillin-resistant Staphylococcus aureus (USA300) in an established murine implant-associated osteomyelitis model. Bacterial burden was assessed by colony forming units (CFUs), tissue damage was assessed by histology and micro-computer tomography (µCT), biofilm was assessed by scanning electron microscopy (SEM), host gene expression was assessed by quantitative polymerase chain reaction (qPCR), and osseous integration was assessed via biomechanical push-out test. While CFUs were recovered from RP62A contaminated implants and surrounding tissues after 14 days, the bacterial burden was significantly less than USA300-infected tibiae (p<0.001). Additionally, RP62A failed to produce any of the gross pathologies induced by USA300 (osteolysis, reactive bone-formation, Staphylococcus abscess communities, marrow necrosis and biofilm). However, fibrous tissue was present at the implant-host interface, and rigorous SEM confirmed the rare presence of cocci on RP62A-contaminated implants. Gene expression studies revealed that IL-1β, IL-6, RANKL, and TLR-2 mRNA levels in RP62A infected bone were increased versus Sterile controls. Ex vivo push-out testing showed RP62A infected implants required significantly less force compared to the Sterile group (7.5±3.4 N vs. 17.3±4.1 N; p<0.001), but required 10-fold greater force than USA300 infected implants (0.7±0.3 N; p<0.001). Taken together, these findings demonstrate that S. epidermidis is a commensal pathogen whose mechanisms to inhibit osseous integration are limited to minimal biofilm formation on the implant, and low-grade inflammation. This article is protected by copyright. All rights reserved.},
}
@article {pmid31691922,
year = {2019},
author = {Majumdar, M and Misra, TK and Roy, DN},
title = {In vitro anti-biofilm activity of 14-deoxy-11,12-didehydroandrographolide from Andrographis paniculata against Pseudomonas aeruginosa.},
journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]},
volume = {},
number = {},
pages = {},
doi = {10.1007/s42770-019-00169-0},
pmid = {31691922},
issn = {1678-4405},
support = {YSS/2015/001965//Department of Science and Technology, Govt of India/ ; },
abstract = {14-Deoxy-11,12-didehydroandrographolide is a biologically active molecule present in the extract of Andrographis paniculata (Kalmegh), a classic ethnic herbal formula, which has been used for over thousand years as therapeutics to treat numerous infectious diseases like upper respiratory tract infection, urinary tract infection, and many more health issues. The present study is designed to ascertain an inhibitor against biofilm formation from the major metabolites of Andrographis paniculata, because the extract of this herb shows inhibition of bacterial quorum sensing (QS) communication and biofilm development against microorganisms. 14-Deoxy-11,12-didehydroandrographolide at 0.1 mM (sub-MIC dose) with azithromycin (6 μg/mL, sub-MIC) or gentamicin (4 μg/mL, sub-MIC) synergistically inhibits 92% biofilm production by a 48-h treatment against Pseudomonas aeruginosa. Further investigation carried out by atomic force microscopy shows promising reduction in roughness and height of biofilm in the presence of 14-deoxy-11,12-didehydroandrographolide compared with the control group. The content of extracellular polymeric substances, level of pyocyanin production, and synthesis of extracellular protease by P. aeruginosa have also been reduced significantly at around 90% in 14-deoxy-11,12-didehydroandrographolide-treated group. In conclusion, 14-deoxy-11,12-didehydroandrographolide could be used as a drug molecule against biofilm development by inhibiting QS pathway in Pseudomonas aeruginosa.},
}
@article {pmid31690794,
year = {2019},
author = {Brahma, U and Sharma, P and Murthy, S and Sharma, S and Chakraborty, S and Appalaraju, SN and Bhandari, V},
title = {Decreased expression of femXAB genes and fnbp mediated biofilm pathways in OS-MRSA clinical isolates.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {16028},
doi = {10.1038/s41598-019-52557-z},
pmid = {31690794},
issn = {2045-2322},
support = {2016/DST/INSPIRE/04/2015/000242//Department of Science and Technology, Ministry of Science and Technology (DST)/ ; },
abstract = {Methicillin-Resistant Staphylococcus aureus (MRSA) is a significant threat to human health. Additionally, biofilm forming bacteria becomes more tolerant to antibiotics and act as bacterial reservoir leading to chronic infection. In this study, we characterised the antibiotic susceptibility, biofilm production and sequence types (ST) of 74 randomly selected clinical isolates of S. aureus causing ocular infections. Antibiotic susceptibility revealed 74% of the isolates as resistant against one or two antibiotics, followed by 16% multidrug-resistant isolates (MDR), and 10% sensitive. The isolates were characterized as MRSA (n = 15), Methicillin-sensitive S. aureus (MSSA, n = 48) and oxacillin susceptible mecA positive S. aureus (OS-MRSA, n = 11) based on oxacillin susceptibility, mecA gene PCR and PBP2a agglutination test. All OS-MRSA would have been misclassified as MSSA on the basis of susceptibility test. Therefore, both phenotypic and genotypic tests should be included to prevent strain misrepresentation. In addition, in-depth studies for understanding the emerging OS-MRSA phenotype is required. The role of fem XAB gene family has been earlier reported in OS-MRSA phenotype. Sequence analysis of the fem XAB genes revealed mutations in fem × (K3R, H11N, N18H and I51V) and fem B (L410F) genes. The fem XAB genes were also found down-regulated in OS-MRSA isolates in comparison to MRSA. In OS-MRSA isolates, biofilm formation is regulated by fibronectin binding proteins A &amp; B. Molecular typing of the isolates revealed genetic diversity. All the isolates produced biofilm, however, MRSA isolates with strong biofilm phenotype represent a worrisome situation and may even result in treatment failure.},
}
@article {pmid31689511,
year = {2019},
author = {Demir, C and Demirci, M and Yigin, A and Tokman, HB and Cetik Yildiz, S},
title = {Presence of Biofilm and Adhesin Genes in Staphylococcus aureus Strains Taken from Chronic Wound Infections and their Genotypic and Phenotypic Antimicrobial Sensitivity Patterns.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {101584},
doi = {10.1016/j.pdpdt.2019.101584},
pmid = {31689511},
issn = {1873-1597},
abstract = {The purpose of this research was to examine some biofilm (icaA, icaD and bap) and some adhesion (clfA, fnbA, cna) genes, and also assess the genotypic and phenotypic antimicrobial resistance patterns of Staphylococcus aureus strains taken from wound specimens in Mardin, Turkey. A total of 220 wound specimens were investigated. The biofilm forming ability and resistance pattern for eleven antimicrobial agents were investigated by conventional and multiplex PCR methods. S. aureus were taken from 112 (50.9%) of 220 wound specimens. Moreover, biofilm production was found in 79 (70.5%) of the 112 S. aureus isolates. 97 (86.6%) strains of all isolates were positive for icaA and icaD, and 15 (13.4%) for bap. The adhesin genes, cna, fnbA and clfA were detected in 98 (87.5%), 87 (77.7%), and 75 (66.9%) strains, respectively. The numbers of MSSA and MRSA bearing antimicrobial resistance genes were 19 (16.96%) and 32 (28.57%) for blaZ, 9 (8.04%) and 17 (15.18%) for tetK, 6 (5.36%) and 14 (12.5%) for ermC, 2 (1.79%) and 7 (6.25%) for tetM, 0 (0%) and 5 (4.46%) for mecA, 2 (1.79%) and 4 (3.57%) for ermA, 1 (0.89%) and 2 (1.79 %) for both tetK and tetM, respectively. Our findings indicate that multiplex PCR is a suitable way for identifying biofilm and adhesin producing S. aureus. Our data also provided a country-wide oversight of the S. aureus antimicrobial resistance gene profiles for the properly therapy of patients and to control the spreading of the resistance genes.},
}
@article {pmid31687841,
year = {2019},
author = {Wang, T and Flint, S and Palmer, J},
title = {Magnesium and calcium ions: roles in bacterial cell attachment and biofilm structure maturation.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-16},
doi = {10.1080/08927014.2019.1674811},
pmid = {31687841},
issn = {1029-2454},
abstract = {The ubiquitous divalent cations magnesium and calcium are important nutrients required by bacteria for growth and cell maintenance. Multi-faceted roles are shown both in bacterial initial attachment and biofilm maturation. The effects of calcium and magnesium can be highlighted in physio-chemical interactions, gene regulation and bio-macromolecular structural modification, which lead to either promotion or inhibition of biofilms. This review outlines recent research addressing phenotypic changes and mechanisms undertaken by calcium and magnesium in affecting bacterial biofilm formation.},
}
@article {pmid31686691,
year = {2019},
author = {Lauer Cruz, K and de Souza da Motta, A},
title = {Characterization of biofilm production by Pseudomonas fluorescens isolated from refrigerated raw buffalo milk.},
journal = {Journal of food science and technology},
volume = {56},
number = {10},
pages = {4595-4604},
doi = {10.1007/s13197-019-03924-1},
pmid = {31686691},
issn = {0022-1155},
abstract = {Pseudomonas fluorescens can often be isolated from refrigerated raw milk. Two strains of P. fluorescens PL5.4 and PL7.1, isolated from raw buffalo milk, were evaluated for their proteolytic capacity, exopolysaccharide production and biofilm production. Proteolytic activity was observed in both strains. The P. fluorescens PL5.4 strain presented fluorescence in the presence of calcofluor, indicating exopolysaccharide production. Both strains were able to produce biofilm at 7 °C for 72 h. For the biofilm production test on stainless steel, adherent cell counts of up to 7.1, 7.3 and 8.8 log CFU/cm2 at 7, 23 and 30 °C were obtained. Through scanning electron microscopy, it was possible to observe the biofilm produced by the P. fluorescens PL5.4 strain. Proper cleaning and disinfection practices in order are important to reduce bacterial contamination and extend the useful life of raw material and its derivatives.},
}
@article {pmid31686149,
year = {2019},
author = {Yi, J and Zhang, D and Cheng, Y and Tan, J and Luo, Y},
title = {The impact of Paenibacillus polymyxa HY96-2 luxS on biofilm formation and control of tomato bacterial wilt.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-019-10162-0},
pmid = {31686149},
issn = {1432-0614},
support = {2017YFD0201107-2-3//the National Key Research and Development Program of China/ ; 31501693//the National Natural Science Fund/ ; },
abstract = {The focus of this study was to investigate the effects of luxS, a key regulatory gene of the autoinducer-2 (AI-2) quorum sensing (QS) system, on the biofilm formation and biocontrol efficacy against Ralstonia solanacearum by Paenibacillus polymyxa HY96-2. luxS mutants were constructed and assayed for biofilm formation of the wild-type (WT) strain and luxS mutants of P. polymyxa HY96-2 in vitro and in vivo. The results showed that luxS positively regulated the biofilm formation of HY96-2. Greenhouse experiments of tomato bacterial wilt found that from the early stage to late stage postinoculation, the biocontrol efficacy of the luxS deletion strain was the lowest with 50.70 ± 1.39% in the late stage. However, the luxS overexpression strain had the highest biocontrol efficacy with 75.66 ± 1.94% in the late stage. The complementation of luxS could restore the biocontrol efficacy of the luxS deletion strain with 69.84 ± 1.09% in the late stage, which was higher than that of the WT strain with 65.94 ± 2.73%. Therefore, we deduced that luxS could promote the biofilm formation of P. polymyxa HY96-2 and further promoted its biocontrol efficacy against R. solanacearum.},
}
@article {pmid31685917,
year = {2019},
author = {Noirot-Gros, MF and Forrester, S and Malato, G and Larsen, PE and Noirot, P},
title = {CRISPR interference to interrogate genes that control biofilm formation in Pseudomonas fluorescens.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {15954},
doi = {10.1038/s41598-019-52400-5},
pmid = {31685917},
issn = {2045-2322},
abstract = {Bacterial biofilm formation involves signaling and regulatory pathways that control the transition from motile to sessile lifestyle, production of extracellular polymeric matrix, and maturation of the biofilm 3D structure. Biofilms are extensively studied because of their importance in biomedical, ecological and industrial settings. Gene inactivation is a powerful approach for functional studies but it is often labor intensive, limiting systematic gene surveys to the most tractable bacterial hosts. Here, we adapted the CRISPR interference (CRISPRi) system for use in diverse strain isolates of P. fluorescens, SBW25, WH6 and Pf0-1. We found that CRISPRi is applicable to study complex phenotypes such as cell morphology, motility and biofilm formation over extended periods of time. In SBW25, CRISPRi-mediated silencing of genes encoding the GacA/S two-component system and regulatory proteins associated with the cylic di-GMP signaling messenger produced swarming and biofilm phenotypes similar to those obtained after gene inactivation. Combined with detailed confocal microscopy of biofilms, our study also revealed novel phenotypes associated with extracellular matrix biosynthesis as well as the potent inhibition of SBW25 biofilm formation mediated by the PFLU1114 operon. We conclude that CRISPRi is a reliable and scalable approach to investigate gene networks in the diverse P. fluorescens group.},
}
@article {pmid31685418,
year = {2019},
author = {Adnan, M and Ali Shah, MR and Jamal, M and Jalil, F and Andleeb, S and Nawaz, MA and Pervez, S and Hussain, T and Shah, I and Imran, M and Kamil, A},
title = {Isolation and characterization of bacteriophage to control multidrug-resistant Pseudomonas aeruginosa planktonic cells and biofilm.},
journal = {Biologicals : journal of the International Association of Biological Standardization},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.biologicals.2019.10.003},
pmid = {31685418},
issn = {1095-8320},
abstract = {Pseudomonas aeruginosa is Gram-negative bacterium, one of the leading cause of drug-resistant nosocomial infections in developing countries. This bacterium possesses chromosomally encoded efflux pumps, poor permeability of outer-membrane and high tendency for biofilm formation which are tools to confer resistance. Bacteriophages are regarded as feasible treatment option for control of resistant P. aeruginosa. The aim of the current study was isolate and characterized a bacteriophage against P. aeruginosa with MDR and biofilm ability. A bacteriophage MA-1 with moderate host range was isolated from waste water. The phage was considerable heat and pH stable. Electron microscopy revealed that phage MA-1 belongs to Myoviridae family. Its genome was dsDNA (≈50 kb), coding for eighteen different proteins (ranging from 12 to 250 KDa). P. aeruginosa-2949 log growth phase was significantly reduced by phage MA-1 (2.5 × 103 CFU/ml) as compared to control (without phage). Phage MA-1 also showed significant reductions of 2.0, 2.5 and 3.2 folds in 24, 48, and 74 h old biofilms after 6 h treatment with phage respectively as compared to control. It was concluded from this study that phage MA-1 has capability of killing P. aeruginosa planktonic cells and biofilm, but for complete eradication cocktail will more effective to avoid resistance.},
}
@article {pmid31685050,
year = {2019},
author = {Ribeiro, MM and Graziano, KU and Olson, N and França, R and Alfa, MJ},
title = {The polytetrafluoroethylene (PTFE) channel model of cyclic-buildup biofilm and traditional biofilm: The impact of friction, and detergent on cleaning and subsequent high-level disinfection.},
journal = {Infection control and hospital epidemiology},
volume = {},
number = {},
pages = {1-9},
doi = {10.1017/ice.2019.306},
pmid = {31685050},
issn = {1559-6834},
abstract = {OBJECTIVE: To evaluate the efficacy of detergent and friction on removal of traditional biofilm and cyclic-buildup biofilm (CBB) from polytetrafluoroethylene (PTFE) channels and to evaluate the efficacy of glutaraldehyde to kill residual bacteria after cleaning.<br><br>METHODS: PTFE channels were exposed to artificial test soil containing 108 CFU/mL of Pseudomonas aeruginosa and Enterococcus faecalis, followed by full cleaning and high-level disinfection (HLD) for five repeated rounds to establish CBB. For traditional biofilm, the HLD step was omitted. Cleaning with enzymatic and alkaline detergents, bristle brush, and Pull Thru channel cleaner were compared to a water flush only. Carbohydrate, protein, viable count, adenosine triphosphate (ATP) levels were analyzed and atomic force microscopy (AFM) was performed.<br><br>RESULTS: In the absence of friction, cleaning of traditional biofilm and CBB was not effective compared to the positive control (Dunn-Bonferroni tests; P > .05) regardless of the detergent used. ATP, protein, and carbohydrate analyses were unable to detect traditional biofilm or CBB. The AFM analysis showed that fixation resulted in CBB being smoother and more compact than traditional biofilm.<br><br>CONCLUSION: Friction during the cleaning process was a critical parameter regardless of the detergent used for removal of either traditional biofilm or CBB. Glutaraldehyde effectively killed the remaining microorganisms regardless of the cleaning method used.},
}
@article {pmid31684101,
year = {2019},
author = {Lade, H and Park, JH and Chung, SH and Kim, IH and Kim, JM and Joo, HS and Kim, JS},
title = {Biofilm Formation by Staphylococcus aureus Clinical Isolates is Differentially Affected by Glucose and Sodium Chloride Supplemented Culture Media.},
journal = {Journal of clinical medicine},
volume = {8},
number = {11},
pages = {},
doi = {10.3390/jcm8111853},
pmid = {31684101},
issn = {2077-0383},
support = {2017M3A9E4077232//National Research Foundation of Korea/ ; },
abstract = {Staphylococcus aureus (S. aureus) causes persistent biofilm-related infections. Biofilm formation by S. aureus is affected by the culture conditions and is associated with certain genotypic characteristics. Here, we show that glucose and sodium chloride (NaCl) supplementation of culture media, a common practice in studies of biofilms in vitro, influences both biofilm formation by 40 S. aureus clinical isolates (methicillin-resistant and methicillin-sensitive S. aureus) and causes variations in biofilm quantification. Methicillin-resistant strains formed more robust biofilms than methicillin-sensitive strains in tryptic soy broth (TSB). However, glucose supplementation in TSB greatly promoted and stabilized biofilm formation of all strains, while additional NaCl was less efficient in this respect and resulted in significant variation in biofilm measurements. In addition, we observed that the ST239-SCCmec (Staphylococcal Cassette Chromosome mec) type III lineage formed strong biofilms in TSB supplemented with glucose and NaCl. Links between biofilm formation and accessory gene regulator (agr) status, as assessed by δ-toxin production, and with mannitol fermentation were not found. Our results show that TSB supplemented with 1.0% glucose supports robust biofilm production and reproducible quantification of S. aureus biofilm formation in vitro, whereas additional NaCl results in major variations in measurements of biofilm formation.},
}
@article {pmid31683828,
year = {2019},
author = {Guimerà, X and Moya, A and Dorado, AD and Illa, X and Villa, R and Gabriel, D and Gamisans, X and Gabriel, G},
title = {A Minimally Invasive Microsensor Specially Designed for Simultaneous Dissolved Oxygen and pH Biofilm Profiling.},
journal = {Sensors (Basel, Switzerland)},
volume = {19},
number = {21},
pages = {},
doi = {10.3390/s19214747},
pmid = {31683828},
issn = {1424-8220},
support = {CTQ2015-69802-C2-1-R//Ministerio de Ciencia y Tecnología/ ; },
abstract = {A novel sensing device for simultaneous dissolved oxygen (DO) and pH monitoring specially designed for biofilm profiling is presented in this work. This device enabled the recording of instantaneous DO and pH dynamic profiles within biofilms, improving the tools available for the study and the characterization of biological systems. The microsensor consisted of two parallel arrays of microelectrodes. Microelectrodes used for DO sensing were bare gold electrodes, while microelectrodes used for pH sensing were platinum-based electrodes modified using electrodeposited iridium oxide. The device was fabricated with a polyimide (Kapton®) film of 127 µm as a substrate for minimizing the damage caused on the biofilm structure during its insertion. The electrodes were covered with a Nafion® layer to increase sensor stability and repeatability and to avoid electrode surface fouling. DO microelectrodes showed a linear response in the range 0-8 mg L-1, a detection limit of 0.05 mg L-1, and a sensitivity of 2.06 nA L mg-1. pH electrodes showed a linear super-Nernstian response (74.2 ± 0.7 mV/pH unit) in a wide pH range (pH 4-9). The multi-analyte sensor array was validated in a flat plate bioreactor where simultaneous and instantaneous pH and DO profiles within a sulfide oxidizing biofilm were recorded. The electrodes spatial resolution, the monitoring sensitivity, and the minimally invasive features exhibited by the proposed microsensor improved biofilm monitoring performance, enabling the quantification of mass transfer resistances and the assessment of biological activity.},
}
@article {pmid31682418,
year = {2019},
author = {Nisbett, LM and Binnenkade, L and Bacon, BA and Hossain, S and Kotloski, NJ and Brutinel, ED and Hartmann, R and Drescher, K and Arora, DP and Muralidharan, S and Thormann, K and Gralnick, JA and Boon, EM},
title = {NosP signaling modulates the NO/H-NOX-mediated multicomponent c-di-GMP network and biofilm formation in Shewanella oneidensis.},
journal = {Biochemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.biochem.9b00706},
pmid = {31682418},
issn = {1520-4995},
abstract = {Biofilms form when bacteria aggregate in a self-secreted exopolysaccharide matrix. Biofilms are resistant to antibiotics and thus implicated in human disease. Nitric oxide (NO) is known to mediate biofilm formation in many bacteria via ligation to H-NOX (heme-NO/oxygen binding) proteins. Most NO-responsive bacteria, however, lack H-NOX domain-containing proteins. Our lab has identified another NO-sensing protein (NosP), which is predicted to be involved in two-component signaling networks that regulate biofilm formation in many bacterial species. Here we demonstrate that NosP participates in the previously described H-NOX/NO-responsive multicomponent c-di-GMP signaling network in Shewanella oneidensis. Strains lacking either nosP or its co-cistronic histidine kinase nahK (previously called hnoS) produce immature biofilms, while hnoX and hnoK (histidine kinase responsive to NO/H-NOX) mutants result in wild type biofilm architecture. We demonstrate that NosP regulates the autophosphorylation activity of NahK as well as HnoK. HnoK and NahK have been shown to control the activities of three response regulator proteins (HnoB, HnoC, and HnoD) that together comprise a NO-responsive multicomponent c-di-GMP signaling network. Based on the data presented here, we propose that NosP/NahK adds a level of regulation on top of H-NOX/HnoK to modulate this c-di-GMP signaling network, and ultimately provide temporal regulation of biofilm formation, by governing phosphate flux through both the HnoK and NahK two-component kinases. Further, it appears that NosP and H-NOX each act to counter the activity of the other in a push-pull mechanism; NosP/NahK promotes biofilm formation through inhibition of H-NOX/HnoK signaling, which on its own reduces biofilm formation. Addition of NO to this system results in a reduction of c-di-GMP concentration and biofilm formation, primarily through disinhibition of HnoK activity.},
}
@article {pmid31681870,
year = {2019},
author = {Kumari, P and Arora, N and Chatrath, A and Gangwar, R and Pruthi, V and Poluri, KM and Prasad, R},
title = {Delineating the Biofilm Inhibition Mechanisms of Phenolic and Aldehydic Terpenes against Cryptococcus neoformans.},
journal = {ACS omega},
volume = {4},
number = {18},
pages = {17634-17648},
doi = {10.1021/acsomega.9b01482},
pmid = {31681870},
issn = {2470-1343},
abstract = {The recalcitrant biofilm formed by fungus Cryptococcus neoformans is a life-threatening pathogenic condition responsible for further intensifying cryptococcosis. Considering the enhanced biofilm resistance and toxicity of synthetic antifungal drugs, the search for efficient, nontoxic, and cost-effective natural therapeutics has received a major boost. Phenolic (thymol and carvacrol) and aldehydic (citral) terpenes are natural and safe alternatives capable of efficient microbial biofilm inhibition. However, the biofilm inhibition mechanism of these terpenes still remains unclear. In this study, we adopted an integrative biophysical and biochemical approach to elucidate the hierarchy of their action against C. neoformans biofilm cells. The microscopic analysis revealed disruption of the biofilm cell surface with elevation in surface roughness and reduction in cell height. Although all terpenes acted through ergosterol biosynthesis inhibition, the phenolic terpenes also selectively interacted via ergosterol binding. Further, the alterations in the fatty acid profile in response to terpenes attenuated the cell membrane fluidity with enhanced permeability, resulting in pore formation and efflux of the K+/intracellular content. Additionally, mitochondrial depolarization caused higher levels of reactive oxygen species, which led to increased lipid peroxidation and activation of the antioxidant defense system. Indeed, the oxidative stress caused a significant decline in the amount of extracellular polymeric matrix and capsule sugars (mannose, xylose, and glucuronic acid), leading to a reduced capsule size and an overall negative charge on the cell surface. This comprehensive data revealed the mechanistic insights into the mode of action of terpenes on biofilm inhibition, which could be exploited for formulating novel anti-biofilm agents.},
}
@article {pmid31681633,
year = {2019},
author = {Swetha, TK and Pooranachithra, M and Subramenium, GA and Divya, V and Balamurugan, K and Pandian, SK},
title = {Umbelliferone Impedes Biofilm Formation and Virulence of Methicillin-Resistant Staphylococcus epidermidis via Impairment of Initial Attachment and Intercellular Adhesion.},
journal = {Frontiers in cellular and infection microbiology},
volume = {9},
number = {},
pages = {357},
doi = {10.3389/fcimb.2019.00357},
pmid = {31681633},
issn = {2235-2988},
abstract = {Staphylococcus epidermidis is an opportunistic human pathogen, which is involved in numerous nosocomial and implant associated infections. Biofilm formation is one of the prime virulence factors of S. epidermidis that supports its colonization on biotic and abiotic surfaces. The global dissemination of three lineages of S. epidermidis superbugs highlights its clinical significance and the imperative need to combat its pathogenicity. Thus, in the current study, the antibiofilm activity of umbelliferone (UMB), a natural product of the coumarin family, was assessed against methicillin-resistant S. epidermidis (MRSE). UMB exhibited significant antibiofilm activity (83%) at 500 μg/ml concentration without growth alteration. Microscopic analysis corroborated the antibiofilm potential of UMB and unveiled its potential to impair intercellular adhesion, which was reflected in auto-aggregation and solid phase adherence assays. Furthermore, real time PCR analysis revealed the reduced expression of adhesion encoding genes (icaD, atlE, aap, bhp, ebh, sdrG, and sdrF). Down regulation of agrA and reduced production of secreted hydrolases upon UMB treatment were speculated to hinder invasive lifestyle of MRSE. Additionally, UMB hindered slime synthesis and biofilm matrix components, which were believed to augment antibiotic susceptibility. In vivo assays using Caenorhabditis elegans divulged the non-toxic nature of UMB and validated the antibiofilm, antivirulence, and antiadherence properties of UMB observed in in vitro assays. Thus, UMB impairs MRSE biofilm by turning down the initial attachment and intercellular adhesion. Altogether, the obtained results suggest the potent antibiofilm activity of UMB and the feasibility of using it in clinical settings for combating S. epidermidis infections.},
}
@article {pmid31680469,
year = {2019},
author = {Nakagami, G and Schultz, G and Kitamura, A and Minematsu, T and Akamata, K and Suga, H and Kurita, M and Hayashi, C and Sanada, H},
title = {Rapid detection of biofilm by wound blotting following sharp debridement of chronic pressure ulcers predicts wound healing: A preliminary study.},
journal = {International wound journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/iwj.13256},
pmid = {31680469},
issn = {1742-481X},
support = {17H04455//Japan Society for the Promotion of Science/ ; },
abstract = {For optimal wound bed preparation, wound debridement is essential to eliminate bacterial biofilms. However, it is challenging for clinicians to determine whether the biofilm is completely removed. A newly developed biofilm detection method based on wound blotting technology may be useful. Thus, we aimed to investigate the effect of biofilm elimination on wound area decrease in pressure ulcers, as confirmed using the wound blotting method. In this retrospective observational study, we enrolled patients with pressure ulcers who underwent sharp debridement with pre- and post-debridement wound blotting. Biofilm was detected on the nitrocellulose membrane using ruthenium red or alcian blue staining. Patients were included if the test was positive for biofilm before wound debridement. Percent decrease in wound area after 1 week was calculated as an outcome measure. We classified the wounds into a biofilm-eliminated group and a biofilm-remaining group based on the post-debridement wound blotting result. Sixteen wound blotting samples from nine pressure ulcers were collected. The percent decrease in wound area was significantly higher in the biofilm-eliminated group (median: 14.4%, interquartile range: 4.6%-20.1%) than in the biofilm-remaining group (median: -14.5%, interquartile range: -25.3%-9.6%; P = .040). The presence of remaining biofilms was an independent predictor for reduced percent decrease in wound area (coefficient = -22.84, P = .040). Biofilm-based wound care guided by wound blotting is a promising measure to help clinicians eliminate bacterial bioburden more effectively for wound area reduction.},
}
@article {pmid31680421,
year = {2019},
author = {Røder, HL and Liu, W and Sørensen, SJ and Madsen, JS and Burmølle, M},
title = {Interspecies interactions reduce selection for a biofilm optimized variant in a four-species biofilm model.},
journal = {Environmental microbiology reports},
volume = {},
number = {},
pages = {},
doi = {10.1111/1758-2229.12803},
pmid = {31680421},
issn = {1758-2229},
abstract = {Multispecies biofilms are structured and spatially defined communities, where interspecies interactions impact assembly and functionality. Here we compared the spatial organization and growth of bacterial cells in differently composed biofilm communities over time to determine links between interspecies interactions and selection for biofilm phenotypes of individual species. An established model community consisting of Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus was used. It was found that interspecies interactions led to varying levels of selection for a new colony phenotype of X. retroflexus, depending on the presence/absence of other species. When M. oxydans was absent, X. retroflexus was not able to establish in the top layers of the biofilm, which led to selection for a hyper-matrix forming phenotype of X. retroflexus that successfully established in the biofilm top layers. No such phenotypic X. retroflexus variants were identified in the presence of M. oxydans. These findings indicate that interspecies interactions may lead to favourable localization of individual species in a multispecies biofilm and thereby reduce selection for competitive phenotypes. This article is protected by copyright. All rights reserved.},
}
@article {pmid31679132,
year = {2019},
author = {Gabriel, C and Grenho, L and Cerqueira, F and Medeiros, R and Dias, AM and Ribeiro, AI and Proença, MF and Fernandes, MH and Sousa, JC and Monteiro, FJ and Ferraz, MP},
title = {Inhibitory Effect of 5-Aminoimidazole-4-Carbohydrazonamides Derivatives Against Candida spp. Biofilm on Nanohydroxyapatite Substrate.},
journal = {Mycopathologia},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11046-019-00400-4},
pmid = {31679132},
issn = {1573-0832},
support = {PTDC/SAU-BMA/111233/2009//Fundação para a Ciência e a Tecnologia/ ; SFRH/BD/72866/2010//Fundação para a Ciência e a Tecnologia/ ; },
abstract = {Candida can adhere and form biofilm on biomaterials commonly used in medical devices which is a key attribute that enhances its ability to cause infections in humans. Furthermore, biomaterial-related infections represent a major therapeutic challenge since Candida biofilms are implicated in antifungal therapies failure. The goals of the present work were to investigate the effect of three 5-aminoimidazole-4-carbohydrazonamides, namely (Z)-5-amino-1-methyl-N'-aryl-1H-imidazole-4-carbohydrazonamides [aryl = phenyl (1a), 4-fluorophenyl (1b), 3-fluorophenyl (1c)], on Candida albicans and Candida krusei biofilm on nanohydroxyapatite substrate, a well-known bioactive ceramic material. To address these goals, both quantitative methods (by cultivable cell numbers) and qualitative evaluation (by scanning electron microscopy) were used. Compounds cytocompatibility towards osteoblast-like cells was also evaluated after 24 h of exposure, through resazurin assay. The three tested compounds displayed a strong inhibitory effect on biofilm development of both Candida species as potent in vitro activity against C. albicans sessile cells. Regarding cytocompatibility, a concentration-dependent effect was observed. Together, these findings indicated that the potent activity of imidazole derivatives on Candida spp. biofilms on nanohydroxyapatite substrate, in particular compound 1c, is worth further investigating.},
}
@article {pmid31678888,
year = {2019},
author = {Zhang, H and Wang, H and Jie, M and Zhang, K and Qian, Y and Ma, J},
title = {Performance and microbial communities of different biofilm membrane bioreactors with pre-anoxic tanks treating mariculture wastewater.},
journal = {Bioresource technology},
volume = {295},
number = {},
pages = {122302},
doi = {10.1016/j.biortech.2019.122302},
pmid = {31678888},
issn = {1873-2976},
abstract = {The performance of pollutant removals, activated sludge characteristics, and microbial communities of two biofilm membrane bioreactors coupled with pre-anoxic tanks (BF-AO-MBRs) (one using fiber bundle bio-carriers (FB-MBR) and the other using suspended bio-carriers (MB-MBR)) were compared at the salinity between zero and 60 g/L. At all salinities, three bioreactors showed good COD average removal efficiencies (>94.1%), and FB-MBR showed the best TN removal efficiency (90.4% at 30 g/L salinity). Moreover, FB-MBR had the faster process start-up time and better salt shock resistance. At high salinities (30-60 g/L), more extracellular polymeric substances were produced by the BF-AO-MBRs to avoid the penetration of salt and protect the bacterial community. Because of the different attachment patterns of biofilms, the microbial community structure in the FB-MBR exposed to 30 g/L salinity had higher nitrite-oxidizing/ammonia-oxidizing bacteria ratio (6.44) with more abundance of denitrifiers, which contribute to higher TN removal efficiency and lower nitrite accumulation.},
}
@article {pmid31678321,
year = {2019},
author = {D'Andrea, MM and Frezza, D and Romano, E and Marmo, P and De Angelis, LH and Perini, N and Thaller, MC and Di Lallo, G},
title = {The lytic bacteriophage vB_EfaH_EF1TV, a new member of the Herelleviridae family, disrupts biofilm produced by Enterococcus faecalis clinical strains.},
journal = {Journal of global antimicrobial resistance},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jgar.2019.10.019},
pmid = {31678321},
issn = {2213-7173},
abstract = {OBJECTIVES: The aim of this study is to characterize a new bacteriophage able to infect Enterococcus faecalis, and to evaluate its ability to disrupt biofilm.<br><br>METHODS: The vB_EfaH_EF1TV (EF1TV) host-range was determined by spot test and efficiency of plating using a collection of 15E. faecalis clinical strains. The phage genome was sequenced with a next generation sequencing approach. Anti-biofilm activity was tested by crystal violet method and confocal laser scanning microscopy. Phage-resistant mutants were selected and sequenced to investigate receptors exploited by phage for infection.<br><br>RESULTS: EF1TV is a newly discoveredE. faecalis phage which belongs to the Herelleviridae family. EF1TV, whose genome is 98% identical to φEF24C, is characterized by a linear dsDNA genome of 143,507 bp with direct terminal repeats of 1,911 bp. The phage is able to infect E. faecalis and shows also the ability to degrade biofilm produced by strains of this species. The results were confirmed by confocal laser scanning microscopy analyzing the biofilm reduction in the same optical field before and after phage infection.<br><br>CONCLUSIONS: The EF1TV phage shows promising features such as an obligatory lytic nature, an anti-biofilm activity and the absence of integration-related proteins, antibiotic resistance determinants and virulence factors, and therefore could be a promising tool for therapeutic applications.},
}
@article {pmid31677806,
year = {2019},
author = {Rathinam, NK and Gorky, and Bibra, M and Salem, DR and Sani, RK},
title = {Bioelectrochemical approach for enhancing lignocellulose degradation and biofilm formation in Geobacillus strain WSUCF1.},
journal = {Bioresource technology},
volume = {},
number = {},
pages = {122271},
doi = {10.1016/j.biortech.2019.122271},
pmid = {31677806},
issn = {1873-2976},
abstract = {Investigations on microbial electrocatalysis as a strategy for enhancing the rates of substrate utilization leading to enhanced yield of biomass and enhanced biofilm formation are reported. A thermophilic Geobacillus sp. strain WSUCF1 (60 °C), a potential lignocellulose degrading microorganism was used as the electrocatalyst. Glucose, cellulose, and corn stover were used as the feedstocks. The results of this investigation showed that applying the oxidation potential of -0.383 mV (vs PRE) increased the glucose utilization and COD removal by 25.5% and 29.7% respectively. The bioelectrocatalysis strategy also increased the biomass yield by 81.2, 42.1, and 49.5% in the case of systems fed with glucose, cellulose, and corn stover, respectively, when compared with the systems without applied oxidation potential. This is the first work reporting the effects of applied oxidation potential on increasing the rates of degradation of lignocellulosic biomass and enhanced biofilm formation.},
}
@article {pmid31677404,
year = {2019},
author = {Li, H and Song, HL and Xu, H and Lu, Y and Zhang, S and Yang, YL and Yang, XL and Lu, YX},
title = {Effect of the coexposure of sulfadiazine, ciprofloxacin and zinc on the fate of antibiotic resistance genes, bacterial communities and functions in three-dimensional biofilm-electrode reactors.},
journal = {Bioresource technology},
volume = {296},
number = {},
pages = {122290},
doi = {10.1016/j.biortech.2019.122290},
pmid = {31677404},
issn = {1873-2976},
abstract = {Three-dimensional biofilm electrode reactors (3D-BERs) with high treatment efficiency were constructed to treat wastewater containing sulfadiazine (SDZ) and ciprofloxacin (CIP) coexposure with Zinc (Zn). The results showed that coexposure to target antibiotics and Zn increased the absolute and relative abundances of target antibiotic resistance genes (ARGs). Additionally, the target ARG abundances were higher on cathode of 3D-BER compared with ordinary anaerobic reactor while the abundances of total ARGs were decreased in the effluent. Meanwhile, redundancy analysis results revealed that the composition of bacteria carrying ARGs was greatly influenced in the cathode by the accumulation of Zn and antibiotic, which dominated the changes of ARG abundances. Additionally, ARGs with their host bacteria revealed by network analysis were partially deposited on electrode substrates when being removed from wastewater. Thus, 3D-BER exhibits capability of simultaneously eliminating antibiotic and Zn, and greatly reduces the risks of ARGs spread.},
}
@article {pmid31676401,
year = {2019},
author = {Kipanga, PN and Liu, M and Panda, SK and Mai, AH and Veryser, C and Van Puyvelde, L and De Borggraeve, WM and Van Dijck, P and Matasyoh, J and Luyten, W},
title = {Biofilm inhibiting properties of compounds from the leaves of Warburgia ugandensis Sprague subsp ugandensis against Candida and staphylococcal biofilms.},
journal = {Journal of ethnopharmacology},
volume = {},
number = {},
pages = {112352},
doi = {10.1016/j.jep.2019.112352},
pmid = {31676401},
issn = {1872-7573},
abstract = {Warburgia ugandensis Sprague subspecies ugandensis is a plant widely distributed in Eastern, Central and Southern Africa. In humans, it is used to treat respiratory infections, tooth aches, malaria, skin infections, venereal diseases, diarrhea, fevers and aches.<br><br>AIM OF THE STUDY: This study aims to identify the bioactive compounds against clinically important biofilm-forming strains of Candida and staphylococci that are responsible for tissue and implanted device-related infections.<br><br>METHODS: Using a bioassay-guided fractionation approach, hexane -, ethanol -, acetone - and water extracts from the leaves of W. ugandensis, their subsequent fractions and isolated compounds were tested against both developing and preformed 24 h-biofilms of Candida albicans SC5314, Candida glabrata BG2 Candida glabrata ATCC 2001, Staphylococcus epidermidis 1457 and Staphylococcus aureus USA 300 using microtiter susceptibility tests. Planktonic cells were also tested in parallel for comparison purposes. Confocal scanning laser microscopy was also used to visualize effects of isolated compounds on biofilm formation.<br><br>RESULTS: Warburganal, polygodial and alpha-linolenic acid (ALA) were the major bioactive compounds isolated from the acetone extract of W. ugandensis. For both warburganal and polygodial, the biofilm inhibitory concentration that inhibits 50% of C. albicans developing biofilms (BIC50) was 4.5 ± 1 and 10.8 ± 5 μg/mL respectively. Against S. aureus developing biofilms, this value was 37.9 ± 8 μg/mL and 25 μg/mL with warburganal and ALA respectively. Eradication of preformed 24 h biofilms was also observed. Interestingly, synergy between the sesquiterpenoids and azoles against developing C. albicans biofilms resulted in an approximately ten-fold decrease of the effective concentration required to completely inhibit growth of the biofilms by individual compounds. The hydroxyl group in position C-9 in warburganal was identified as essential for activity against staphylococcal biofilms. We also identified additional promising bioactive sesquiterpenoids; drimenol and drimendiol from the structure-activity relationship (SAR) studies.<br><br>CONCLUSIONS: ALA and four sesquiterpenoids: polygodial, warburganal, drimenol and drimendiol, have shown biofilm-inhibitory activity that has not been reported before and is worth following up. These compounds are potential drug candidates to manage biofilm-based infections, possibly in combination with azoles.},
}
@article {pmid31675521,
year = {2019},
author = {Zhang, X and Song, Z and Hao Ngo, H and Guo, W and Zhang, Z and Liu, Y and Zhang, D and Long, Z},
title = {Impacts of typical pharmaceuticals and personal care products on the performance and microbial community of a sponge-based moving bed biofilm reactor.},
journal = {Bioresource technology},
volume = {295},
number = {},
pages = {122298},
doi = {10.1016/j.biortech.2019.122298},
pmid = {31675521},
issn = {1873-2976},
abstract = {Four lab-scale moving bed biofilm reactors (MBBRs) were built to treat simulated wastewater containing typical pharmaceuticals and personal care products (PPCPs). The efficiency in removing different PPCPs at different concentrations (1, 2 and 5 mg/L) and their effects on the performance of MBBRs were investigated. Results showed that the average removal efficiencies of sulfadiazine, ibuprofen and carbamazepine were 61.1 ± 8.8%, 74.9 ± 8.8% and 28.3 ± 7.4%, respectively. Compared to the reactor without PPCPs, the total nitrogen (TN) removal efficiency of the reactors containing sulfadiazine, ibuprofen and carbamazepine declined by 21%, 30% and 42%, respectively. Based on the microbial community analysis, increasing the PPCPs concentration within a certain range (<2 mg/L) could stimulate microbial growth and increase microbial diversity yet the diversity reduced when the concentration (5 mg/L) exceeded the tolerance of microorganisms. Furthermore the presence and degradation of different PPCPs resulted in a different kind of microbial community structure in the MBBRs.},
}
@article {pmid31675193,
year = {2019},
author = {Tomiyama, K and Shiiya, T and Watanabe, K and Hamada, N and Mukai, Y},
title = {Effect of toothpaste containing multiple ions-releasing filler on polymicrobial biofilm regrowth and dentin demineralization.},
journal = {American journal of dentistry},
volume = {32},
number = {5},
pages = {245-250},
pmid = {31675193},
issn = {0894-8275},
abstract = {PURPOSE: To compare the efficacy of toothpaste containing surface pre-reacted glass-ionomer (S-PRG) filler particles to that of conventional sodium fluoride (NaF) toothpaste for the prevention of dentin demineralization and biofilm regrowth.<br><br>METHODS: Bovine root dentin specimens and glass coverslips were used as biofilm growth substrates. To establish biofilms, glass and dentin specimens were incubated for 72 hours in 0.2% sucrose McBain medium inoculated with stimulated saliva from a single donor. Specimens then received a single 5-minute treatment with S-PRG toothpaste, fluoride toothpaste, or sterilized deionized water and were incubated in McBain medium for 120 hours to allow biofilm regrowth. Output parameters during regrowth (72-192 hours) were pH of spent medium, colony-forming unit (CFU) counts of biofilms, and dentin mineral profiles, integrated mineral loss (IML: vol% × µm), and lesion depth (Ld). Treatment group differences were tested by one-way ANOVA followed by Tukey's multiple range test (P< 0.05).<br><br>RESULTS: At 144 hours, medium pH was significantly higher in the S-PRG-treated dentin group than in the NaF-treated dentin group. In addition, at 192 hours, the CFU count, IML, and Ld were lower in the S-PRG-treated dentin group than in the NaF-treated dentin group. There were significant differences of pH among dentin groups at 72 hours. Treatment with S-PRG toothpaste markedly inhibited dentin demineralization compared to that with NaF toothpaste.<br><br>CLINICAL SIGNIFICANCE: Toothpaste containing multiple ions-releasing filler suppressed bacterial viability and inhibited dentin demineralization.},
}
@article {pmid31673743,
year = {2019},
author = {Ding, XS and Zhao, B and An, Q and Tian, M and Guo, JS},
title = {Role of extracellular polymeric substances in biofilm formation by Pseudomonas stutzeri strain XL-2.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-019-10188-4},
pmid = {31673743},
issn = {1432-0614},
support = {51208534//National Natural Science Foundation of China/ ; cstc2018jscx-msybX0308//Technical Innovation and Application Demonstration Project of CQ CSTC/ ; },
abstract = {Pseudomonas stutzeri strain XL-2 exhibited significant performance on biofilm formation. Extracellular polymeric substances (EPS) secreted by strain XL-2 were characterized by colorimetry and Fourier transform infrared (FT-IR) spectroscopy. The biofilm growth showed a strong positive correlation (rP=0.96, P<0.01) to extracellular protein content, but no correlation to exopolysaccharide content. Hydrolyzing the biofilm with proteinase K caused a significant decrease in biofilm growth (t=3.7, P<0.05), whereas the changes in biofilm growth were not significant when the biofilm was hydrolyzed by α-amylase and β-amylase, implying that proteins rather than polysaccharides played the dominant role in biofilm formation. More specifically, confocal laser scanning microscopy (CLSM) revealed that the extracellular proteins were tightly bound to the cells, resulting in the cells with EPS presenting more biofilm promotion protein secondary structures, such as three-turn helices, β-sheet, and α-helices, than cells without EPS. Both bio-assays and quantitative analysis demonstrated that strain XL-2 produced signal molecules of N-acylhomoserine lactones (AHLs) during biofilm formation process. The concentrations of C6-HLS and C6-oxo-HLS were both significantly positively correlated with protein contents (P<0.05). Dosing exogenous C6-HLS and C6-oxo-HLS also resulted in the increase in protein content. Therefore, it was speculated that C6-HLS and C6-oxo-HLS released by strain XL-2 could up-regulate the secretion of proteins in EPS, and thus promote the formation of biofilm.},
}
@article {pmid31673531,
year = {2019},
author = {Asadian, M and Azimi, L and Alinejad, F and Ostadi, Y and Lari, AR},
title = {Molecular Characterization of Acinetobacter baumannii Isolated from Ventilator-Associated Pneumonia and Burn Wound Colonization by Random Amplified Polymorphic DNA Polymerase Chain Reaction and the Relationship between Antibiotic Susceptibility and Biofilm Production.},
journal = {Advanced biomedical research},
volume = {8},
number = {},
pages = {58},
doi = {10.4103/abr.abr_256_18},
pmid = {31673531},
issn = {2277-9175},
abstract = {Background: Multidrug-resistant Acinetobacter baumannii can cause complications in antibiotic therapy and increase the rate of morbidity and mortality in hospitalized patients. Patients with ventilator and burns are two specific groups at high risk for A. baumannii infections. This study aimed to determine antibiotic susceptibility patterns associated with biofilm production in A. baumannii and to assess its molecular epidemiology by random amplified polymorphic DNA polymerase chain reaction (RAPD PCR) in A. baumannii isolated from ventilator-associated pneumonia and burn wound colonization.<br><br>Materials and Methods: In this study, 79 isolates of A. baumannii (32 ventilator-associated pneumonia [VAP] 47 burns) were collected in two teaching hospitals in Tehran, Iran, in 2018. Conventional biochemical and microbiological methods were used to identify bacteria. Antibiotic susceptibility was detected by disc diffusion methods according to the Clinical and Laboratory Standards Institute 2018. Tube test was examined for the detection of the biofilm formation rate in collected strains. The most prevalent carbapenemase genes were detected by PCR and molecular typing by RAPD PCR.<br><br>Results: All of bacteria were extensively drug-resistant (XDR) except for two isolates. The results of tube test indicated that only 36% of XDR strains were in weak rate of biofilm formation group. Two major clonal genetic groups were found in VAP and burn strains. Oxa-23 was the most prevalent carbapenemase in collected A. baumannii.<br><br>Conclusion: The presence of XDR strains of A. baumannii is considerable significant problem in hospitals. Further, similar genetic clonal identified in them indicated the nosocomial infection origin. Hence, these results are very important for control of nosocomial infection committee in health-care systems.},
}
@article {pmid31673005,
year = {2019},
author = {Brown, JL and Johnston, W and Delaney, C and Rajendran, R and Butcher, J and Khan, S and Bradshaw, D and Ramage, G and Culshaw, S},
title = {Biofilm-stimulated epithelium modulates the inflammatory responses in co-cultured immune cells.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {15779},
doi = {10.1038/s41598-019-52115-7},
pmid = {31673005},
issn = {2045-2322},
support = {BB/P504567/1//RCUK | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; N/A//GlaxoSmithKline (GlaxoSmithKline plc.)/ ; },
abstract = {The gingival epithelium is a physical and immunological barrier to the microbiota of the oral cavity, which interact through soluble mediators with the immune cells that patrol the tissue at the gingival epithelium. We sought to develop a three-dimensional gingivae-biofilm interface model using a commercially available gingival epithelium to study the tissue inflammatory response to oral biofilms associated with &quot;health&quot;, &quot;gingivitis&quot; and &quot;periodontitis&quot;. These biofilms were developed by sequential addition of microorganisms to mimic the formation of supra- and sub-gingival plaque in vivo. Secondly, to mimic the interactions between gingival epithelium and immune cells in vivo, we integrated peripheral blood mononuclear cells and CD14+ monocytes into our three-dimensional model and were able to assess the inflammatory response in the immune cells cultured with and without gingival epithelium. We describe a differential inflammatory response in immune cells cultured with epithelial tissue, and more so following incubation with epithelium stimulated by &quot;gingivitis-associated&quot; biofilm. These results suggest that gingival epithelium-derived soluble mediators may control the inflammatory status of immune cells in vitro, and therefore targeting of the epithelial response may offer novel therapies. This multi-cellular interface model, both of microbial and host origin, offers a robust in vitro platform to investigate host-pathogens at the epithelial surface.},
}
@article {pmid31671860,
year = {2019},
author = {Zhang, Q and Chen, X and Wu, H and Luo, W and Liu, X and Feng, L and Zhao, T},
title = {Comparison of Clay Ceramsite and Biodegradable Polymers as Carriers in Pack-bed Biofilm Reactor for Nitrate Removal.},
journal = {International journal of environmental research and public health},
volume = {16},
number = {21},
pages = {},
doi = {10.3390/ijerph16214184},
pmid = {31671860},
issn = {1660-4601},
support = {NO. 51908099;NO.cstc2018jscx-msybX0134;NO.cstc2018jscx-mszdX0005;NO.cstc2018jscx-mszdX0087//National Natural Science Foundation of China;Chongqing Research Program of Special Innovation Fund for Public Science and Technology, China;Technological Innovation and Application Demonstration of Chongqing, China;/ ; },
abstract = {In recent years, there is a trend of low C/N ratio in municipal domestic wastewater, which results in serious problems for nitrogen removal from wastewater. The addition of an external soluble carbon source has been the usual procedure to achieve denitrification. However, the disadvantage of this treatment process is the need of a closed, rather sophisticated and costly process control as well as the risk of overdosing. Solid-phase denitrification using biodegradable polymers as biofilm carrier and carbon source was considered as an attractive alternative for biological denitrification. The start-up time of the novel process using PCL (polycaprolactone) as biofilm carrier and carbon source was comparable with that of conventional process using ceramsite as biofilm carrier and acetate as carbon source. Further, the solid-phase denitrification process showed higher nitrogen removal efficiency under shorter hydraulic retention time (HRT) and low carbon to nitrogen (C/N) ratio since the biofilm was firmly attached to the clear pores on the surface of PCL carriers and in this process bacteria that could degrade PCL carriers to obtain electron donor for denitrification was found. In addition, solid-phase denitrification process had a stronger resistance of shock loading than that in conventional process. This study revealed, for the first time, that the physical properties of the biodegradable polymer played a vital role in denitrification, and the different microbial compositions of the two processes was the main reason for the different denitrification performances under low C/N ratio.},
}
@article {pmid31671533,
year = {2019},
author = {Alshanta, OA and Shaban, S and Nile, CJ and McLean, W and Ramage, G},
title = {Candida albicans Biofilm Heterogeneity and Tolerance of Clinical Isolates: Implications for Secondary Endodontic Infections.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/antibiotics8040204},
pmid = {31671533},
issn = {2079-6382},
abstract = {AIM: Endodontic infections are caused by the invasion of various microorganisms into the root canal system. Candida albicans is a biofilm forming yeast and the most prevalent eukaryotic microorganism in endodontic infections. In this study we investigated the ability of C. albicans to tolerate treatment with standard endodontic irrigants NaOCl (sodium hypochlorite), ethylenediaminetetraacetic acid (EDTA) and a combination thereof. We hypothesized that biofilm formed from a panel of clinical isolates differentially tolerate disinfectant regimens, and this may have implications for secondary endodontic infections.<br><br>METHODOLOGY: Mature C. albicans biofilms were formed from 30 laboratory and oral clinical isolates and treated with either 3% NaOCl, 17% EDTA or a sequential treatment of 3% NaOCl followed by 17% EDTA for 5 min. Biofilms were then washed, media replenished and cells reincubated for an additional 24, 48 and 72 h at 37 °C. Regrowth was quantified using metabolic reduction, electrical impedance, biofilm biomass and microscopy at 0, 24, 48 and 72 h.<br><br>RESULTS: Microscopic analysis and viability readings revealed a significant initial killing effect by NaOCl, followed by a time dependent significant regrowth of C. albicans, but with inter-strain variability. In contrast to NaOCl, there was a continuous reduction in viability after EDTA treatment. Moreover, EDTA significantly inhibited regrowth after NaOCl treatment, though viable cells were still observed.<br><br>CONCLUSIONS: Our results indicate that different C. albicans biofilm phenotypes grown in a non-complex surface topography have the potential to differentially tolerate standard endodontic irrigation protocols. This is the first study to report a strain dependent impact on efficacy of endodontic irrigants. Its suggested that within the complex topography of the root canal, a more difficult antimicrobial challenge, that existing endodontic irrigant regimens permit cells to regrow and drive secondary infections.},
}
@article {pmid31669377,
year = {2019},
author = {Cockeran, R and Dix-Peek, T and Dickens, C and Steel, HC and Anderson, R and Feldman, C},
title = {Biofilm formation and induction of stress response genes is a common response of several serotypes of the pneumococcus to cigarette smoke condensate.},
journal = {The Journal of infection},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jinf.2019.10.014},
pmid = {31669377},
issn = {1532-2742},
abstract = {OBJECTIVES: Exposure to cigarette smoke impacts on the virulence of Streptococcus pneumoniae (pneumococcus) by mechanisms including induction of biofilm formation. Most studies, however, have focused on individual strains of the pneumococcus. Accordingly, the current study has investigated the commonality of the pneumococcal stress response to cigarette smoke condensate (CSC), using five different strains of the pathogen.<br><br>METHODS: Following exposure to CSC at final concentrations of 80 and 160 µg.mL-1 during a 16 hour incubation period, biofilm formation was measured using a crystal violet-based spectrophotometric procedure. Expression of stress genes seemingly linked to biofilm formation viz. hk11 and rr11 [histidine kinase and response regulator of the two-component regulatory system 11 (TCS11) respectively], cat eff (cation efflux system protein), abc (ATP-binding component of an ATP-binding cassette transporter) and 2005-hyp (hypothetical gene) was measured by sequential extraction of RNA, cDNA synthesis and real-time qPCR.<br><br>RESULTS: Exposure of all five strains of the pneumococcus to CSC, resulted in significant biofilm formation, as well as induction of all five test stress genes.<br><br>CONCLUSIONS: Augmentation of induction of selective stress genes and biofilm formation are common, possibly linked, responses of various serotypes of the pneumococcus to CSC, favouring both persistence of the pathogen and decreased efficacy of antibiotics.},
}
@article {pmid31667388,
year = {2019},
author = {Torres, G and Vargas, K and Sánchez-Jiménez, M and Reyes-Velez, J and Olivera-Angel, M},
title = {Genotypic and phenotypic characterization of biofilm production by Staphylococcus aureus strains isolated from bovine intramammary infections in Colombian dairy farms.},
journal = {Heliyon},
volume = {5},
number = {10},
pages = {e02535},
doi = {10.1016/j.heliyon.2019.e02535},
pmid = {31667388},
issn = {2405-8440},
abstract = {The ability of Staphylococcus aureus to form biofilms is an important virulence factor because this has been associated with persistent bovine intramammary infections. Different mechanisms of biofilm formation have been described in S. aureus; however, the process has been found to be mainly driven by the ica and bap genes. The presence of the ica and bap genes, as well as the biofilm formation in vitro were evaluated in 229 S. aureus strains isolated from bovine milk collected from different regions of Department of Antioquia, Colombia. Three different genotypes grouped into three separate clusters were identified from in vitro assays. Genotype 1 (ica positive and bap negative) was the most prevalent (78.17%), followed by genotype 2 (ica and bap positive) (12.66%) and genotype 0 (ica and bap negative) (9.17%). Biofilm formation was observed in 81.26% of the strains from which 100% of genotype 2 isolates showed biofilm formation. The biofilms formed by genotype 2 isolates were also found to have the highest optical density (>2.4). These results showed that most of the S. aureus strains were capable of biofilm formation, suggesting the virulence potential particularly in bap-positive strains.},
}
@article {pmid31666981,
year = {2019},
author = {Yung, YP and McGill, SL and Chen, H and Park, H and Carlson, RP and Hanley, L},
title = {Reverse diauxie phenotype in Pseudomonas aeruginosa biofilm revealed by exometabolomics and label-free proteomics.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {31},
doi = {10.1038/s41522-019-0104-7},
pmid = {31666981},
issn = {2055-5008},
abstract = {Microorganisms enhance fitness by prioritizing catabolism of available carbon sources using a process known as carbon catabolite repression (CCR). Planktonically grown Pseudomonas aeruginosa is known to prioritize the consumption of organic acids including lactic acid over catabolism of glucose using a CCR strategy termed &quot;reverse diauxie.&quot; P. aeruginosa is an opportunistic pathogen with well-documented biofilm phenotypes that are distinct from its planktonic phenotypes. Reverse diauxie has been described in planktonic cultures, but it has not been documented explicitly in P. aeruginosa biofilms. Here a combination of exometabolomics and label-free proteomics was used to analyze planktonic and biofilm phenotypes for reverse diauxie. P. aeruginosa biofilm cultures preferentially consumed lactic acid over glucose, and in addition, the cultures catabolized the substrates completely and did not exhibit the acetate secreting &quot;overflow&quot; metabolism that is typical of many model microorganisms. The biofilm phenotype was enabled by changes in protein abundances, including lactate dehydrogenase, fumarate hydratase, GTP cyclohydrolase, L-ornithine N(5)-monooxygenase, and superoxide dismutase. These results are noteworthy because reverse diauxie-mediated catabolism of organic acids necessitates a terminal electron acceptor like O2, which is typically in low supply in biofilms due to diffusion limitation. Label-free proteomics identified dozens of proteins associated with biofilm formation including 16 that have not been previously reported, highlighting both the advantages of the methodology utilized here and the complexity of the proteomic adaptation for P. aeruginosa biofilms. Documenting the reverse diauxic phenotype in P. aeruginosa biofilms is foundational for understanding cellular nutrient and energy fluxes, which ultimately control growth and virulence.},
}
@article {pmid31665633,
year = {2019},
author = {Xu, Z and Mandic-Mulec, I and Zhang, H and Liu, Y and Sun, X and Feng, H and Xun, W and Zhang, N and Shen, Q and Zhang, R},
title = {Antibiotic Bacillomycin D Affects Iron Acquisition and Biofilm Formation in Bacillus velezensis through a Btr-Mediated FeuABC-Dependent Pathway.},
journal = {Cell reports},
volume = {29},
number = {5},
pages = {1192-1202.e5},
doi = {10.1016/j.celrep.2019.09.061},
pmid = {31665633},
issn = {2211-1247},
abstract = {Bacillus spp. produce a wide range of secondary metabolites, including antibiotics, which have been well studied for their antibacterial properties but less so as signaling molecules. Previous results indicated that the lipopeptide bacillomycin D is a signal that promotes biofilm development of Bacillus velezensis SQR9. However, the mechanism behind this signaling is still unknown. Here, we show that bacillomycin D promotes biofilm development by promoting the acquisition of iron. Bacillomycin D promotes the transcription of the iron ABC transporter FeuABC by binding to its transcription factor, Btr. These actions increase intracellular iron concentration and activate the KinB-Spo0A-SinI-SinR-dependent synthesis of biofilm matrix components. We demonstrate that this strategy is beneficial for biofilm development and competition with the Pseudomonas fluorescens PF-5. Our results unravel an antibiotic-dependent signaling mechanism that links iron acquisition to biofilm development and ecological competition.},
}
@article {pmid31663721,
year = {2019},
author = {Zhong, N and Wu, Y and Wang, Z and Chang, H and Zhong, D and Xu, Y and Hu, X and Huang, L},
title = {Monitoring Microalgal Biofilm Growth and Phenol Degradation with Fiber-optic Sensors.},
journal = {Analytical chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.analchem.9b03923},
pmid = {31663721},
issn = {1520-6882},
abstract = {Simple D-type plastic optical fiber (POF) probes (i.e., sensor, reference, and photochemical probes) were created to accurately monitor the progression and phenol degradation of a Chlorella vulgaris biofilm. The sensor and reference probes were used to monitor the biofilm growth (thickness). The sensor probe, which consisted of a D-shaped POF and Canada balsam doped with GeO2 (CBG) coating, was developed to monitor the biofilm growth and change in the liquid-phase composition and its concentration inside the biofilm. The reference probe, which comprised a D-shaped POF, CBG coating, and glass fiber membrane (to separate the liquids from Chlorella vulgaris), was used to measure the response to changes in the liquid phase. A model was developed to demonstrate the accurate measurement of the biofilm thickness. The photochemical POF probe was coupled with a high-permselectivity phenol polymer membrane to monitor the phenol concentration and analyze the degradation time of 50 mg/L phenol with microalgal biofilms. A fixed relationship was obtained between the biofilm sensor output information and biofilm thickness for a biofilm thickness range of 0-290 µm with a periodic supply of 50 mg/L phenol solution. The highest phenol degradation rate occurred at a biofilm thickness of 191-222 µm. The proposed system can be used to investigate microalgal biomass and can provide a promising avenue for research on renewable resources and pollutant degradation.},
}
@article {pmid31663364,
year = {2019},
author = {Tsiaprazi-Stamou, A and Monfort, IY and Romani, AM and Bakalis, S and Gkatzionis, K},
title = {The synergistic effect of enzymatic detergents on biofilm cleaning from different surfaces.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-17},
doi = {10.1080/08927014.2019.1666108},
pmid = {31663364},
issn = {1029-2454},
abstract = {Biofilm growth is a significant source of contamination in the food industry. Enzymes are considered green countermeasures against biofilm formation in the food industry owing to their biodegradability and low toxicity. In this study, the synergistic effect of enzymes was studied against biofilm cleaning from hard surfaces. A mixed-microbial sample was sourced from a meat packaging line and biofilms were grown under high shear conditions on stainless steel and polyethylene surfaces. A model cleaning-in-place (CIP) parallel-plate flow chamber was used for firstly, the enzymatic cleaning and secondly, a disinfection step. The cleaning effectiveness was evaluated in response to different formulations containing non-foaming commercial surfactants among with amylase, protease and lipase at neutral pH. The formulation combining all three enzymes was the most effective, showing a synergy essential for the deformation of biofilm structure and consequently better disinfection of both material surfaces.},
}
@article {pmid31659674,
year = {2019},
author = {Abbas, AF and Al-Saadi, AGM and Alkhudhairy, MK},
title = {Biofilm Formation and Virulence Determinants of Klebsiella oxytoca Clinical Isolates from Patients with Colorectal Cancer.},
journal = {Journal of gastrointestinal cancer},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12029-019-00317-7},
pmid = {31659674},
issn = {1941-6636},
abstract = {OBJECTIVE: Biofilm formation has made the therapy of bacterial infections more difficult. The objective our study was assessment of pan-drug-resistant (PDR) Klebsiella oxytoca pathogenicity and virulence factors causing AAHC in patients with colorectal cancer (CRC).<br><br>MATERIALS AND METHODS: Among a total of 300 healthy and 300 patients with antibiotic-associated hemorrhagic colitis (AAHC) and CRC, 200 K. oxytoca were identified during May 2015-January 2019. The virulence properties and biofilm formation among the isolates were investigated by phenotypic, PCR, and real-time PCR (RT-qPCR) techniques.<br><br>RESULTS: The blaCTX-M1 (20%), blaSHV (11%), blaTEM1 (33%), and AmpC encoding CIT (2%) ESBL genes, carbapenemase-encoding genes blaIM (4%) and blaOXA-48 (2%), and colistin-resistant mcr-1 gene (2.5%) were detected. The virulence-encoding genes including fimA (80%), pilQ (100%), matB (100%), mrkA (80%), and npsB (100%) were amplified. Therefore, PDR K. oxytoca containing adhesins and toxin-encoding genes with ability of biofilm formation causing AAHC and CRC were isolated. There was a significant difference between healthy and patients with CRC regarding the presence of K. oxytoca (p = 00.221).<br><br>CONCLUSION: Bacterial enteric pathogens possibly play a role in CRC. Biofilm formation by K. oxytoca strains prevents the efficient infection elimination; therefore, rapid identification and control measure are chief requirements. Additionally, more investigations are necessary with this regard.},
}
@article {pmid31659297,
year = {2019},
author = {Díaz-Pascual, F and Hartmann, R and Lempp, M and Vidakovic, L and Song, B and Jeckel, H and Thormann, KM and Yildiz, FH and Dunkel, J and Link, H and Nadell, CD and Drescher, K},
title = {Breakdown of Vibrio cholerae biofilm architecture induced by antibiotics disrupts community barrier function.},
journal = {Nature microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41564-019-0579-2},
pmid = {31659297},
issn = {2058-5276},
support = {MCB 1817342//National Science Foundation (NSF)/ ; STANTO15RO//Cystic Fibrosis Foundation (CF Foundation)/ ; GM113132//U.S. Department of Health &amp; Human Services | National Institutes of Health (NIH)/ ; CDA00084/2015-C//Human Frontier Science Program (HFSP)/ ; SFB 987//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; 716734//EC | EU Framework Programme for Research and Innovation H2020 | H2020 Priority Excellent Science | H2020 European Research Council (H2020 Excellent Science - European Research Council)/ ; },
abstract = {Bacterial cells in nature are frequently exposed to changes in their chemical environment1,2. The response mechanisms of isolated cells to such stimuli have been investigated in great detail. By contrast, little is known about the emergent multicellular responses to environmental changes, such as antibiotic exposure3-7, which may hold the key to understanding the structure and functions of the most common type of bacterial communities: biofilms. Here, by monitoring all individual cells in Vibrio cholerae biofilms during exposure to antibiotics that are commonly administered for cholera infections, we found that translational inhibitors cause strong effects on cell size and shape, as well as biofilm architectural properties. We identified that single-cell-level responses result from the metabolic consequences of inhibition of protein synthesis and that the community-level responses result from an interplay of matrix composition, matrix dissociation and mechanical interactions between cells. We further observed that the antibiotic-induced changes in biofilm architecture have substantial effects on biofilm population dynamics and community assembly by enabling invasion of biofilms by bacteriophages and intruder cells of different species. These mechanistic causes and ecological consequences of biofilm exposure to antibiotics are an important step towards understanding collective bacterial responses to environmental changes, with implications for the effects of antimicrobial therapy on the ecological succession of biofilm communities.},
}
@article {pmid31658838,
year = {2019},
author = {Flores-Treviño, S and Bocanegra-Ibarias, P and Camacho-Ortiz, A and Morfín-Otero, R and Salazar-Sesatty, HA and Garza-González, E},
title = {Stenotrophomonas maltophilia biofilm: its role in infectious diseases.},
journal = {Expert review of anti-infective therapy},
volume = {},
number = {},
pages = {},
doi = {10.1080/14787210.2019.1685875},
pmid = {31658838},
issn = {1744-8336},
abstract = {Introduction: Infections caused by the opportunistic Stenotrophomonas maltophilia pathogen in immunocompromised patients are complicated to treat due to antibiotic resistance and the ability of the bacteria to produce biofilm. Areas covered: A MEDLINE/PubMed search was performed of available literature to describe the role of biofilm produced by S. maltophilia in the diseases it causes, including biofilm-influencing factors, the biofilm forming process and composition. The antimicrobial resistance due to S. maltophilia biofilm production and current antibiofilm strategies is also included. Expert opinion: Through the production of biofilm, S. maltophilia strains can easily adhere to the surfaces in hospital settings and aid in its transmission. The biofilm can also cause antibiotic tolerance rendering some of the therapeutic options ineffective, causing setbacks in the selection of an appropriate treatment. Conventional susceptibility tests do not yet offer therapeutic guidelines to treat biofilm-associated infections. Current S. maltophilia biofilm control strategies include natural and synthetic compounds, chelating agents, and commonly prescribed antibiotics. As biofilm age and matrix composition affect the level of antibiotic tolerance, their characterization should be included in biofilm susceptibility testing, in addition to molecular and proteomic analyses. As for now, several commonly recommended antibiotics can be used to treat biofilm-related S. maltophilia infections.},
}
@article {pmid31658638,
year = {2019},
author = {Thakur, D and Govindaraju, S and Yun, K and Noh, JS},
title = {The Synergistic Effect of Zinc Ferrite Nanoparticles Uniformly Deposited on Silver Nanowires for the Biofilm Inhibition of Candida albicans.},
journal = {Nanomaterials (Basel, Switzerland)},
volume = {9},
number = {10},
pages = {},
doi = {10.3390/nano9101431},
pmid = {31658638},
issn = {2079-4991},
support = {2019R1A2C1008746//National Research Foundation of Korea/ ; 2016R1D1A1B03932515//National Research Foundation of Korea/ ; },
abstract = {Near-monodisperse zinc ferrite nanoparticles (ZnFe2O4 NPs) are synthesized by a co-precipitation method and deposited on the surface of silver nanowires (AgNWs), employing a stepwise solution method. The resulting hybrid nanostructures (ZnFe2O4@AgNWs) show a thin and uniform layer of ZnFe2O4 NPs at an optimum weight ratio of 1:6 between the two component nanostructures. The hybrid nanostructures retain the high crystal quality and phase purity of their constituents. It is demonstrated that the ZnFe2O4@AgNWs hybrid nanostructures are effective at inhibiting the biofilm formation of Candida albicans cells. The biofilm inhibition activity of the hybrid nanostructures is estimated to be more than 50% at a low concentration of 100 µg/mL from both crystal violet assay and XTT assay, which are more than 8-fold higher than those of pure AgNWs and ZnFe2O4 NPs. This greatly enhanced biofilm inhibition activity is attributed to the ZnFe2O4 NPs-carrying membrane penetration by AgNWs and the subsequent interaction between Candida cells and ZnFe2O4 NPs. These results indicate that the ZnFe2O4@AgNWs hybrid nanostructures have great potential as a new type of novel antibiofilm agent.},
}
@article {pmid31656524,
year = {2019},
author = {Betesho Babrud, R and Kasra Kermanshahi, R and Motamedi Sede, F and Moosavinejad, SZ},
title = {The effect of Lactobacillus reuteri cell free supernatant on growth and biofilm formation of Paenibacillus larvae.},
journal = {Iranian journal of veterinary research},
volume = {20},
number = {3},
pages = {192-198},
pmid = {31656524},
issn = {1728-1997},
abstract = {Background: Paenibacillus larvae is the etiological agent of American foulbrood (AFB) disease, the most lethal disease in honeybee (Apis mellifera) larvae.<br><br>Aims: The aim of the present work was to study the antimicrobial effect of cell free supernatant (CFS) of probiotics on an Iranian isolate's biofilm formation.<br><br>Methods: A local strain was identified by 16S rRNA sequencing. The antibacterial effect of some probiotics was evaluated through drop plate method, minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC) and time-kill assay. The biofilm formation ability of P. larvae and the inhibition of biofilm formation by CFS were studied by microplate and scanning electron microscopy (SEM). The nature of the secondary metabolites in CFS was examined by microscale optical density assay (MODA).<br><br>Results: Alignment of the results of P. larvae KB10 (GenBank accession number MH000685.1) 16S rRNA with the database revealed more than 97% identity with P. larvae. The most antibacterial effect was observed in the CFS of Lactobacillus reuteri ATCC23272 with 12.75 ± 3.2 mm for zone of inhibition (ZOI) at 1000 µL/ml for MIC and MBC. Time-kill assay revealed that CFS eliminated 1.5 × 108 CFU/ml P. larvae KB10 at 2 h of exposure. Microtitre plate and SEM results revealed that CFS (at sub-MIC concentration) was able to inhibit biofilm formation by P. larvae. The results of MODA assay showed that antimicrobial activity were related to the production of organic acids.<br><br>Conclusion: Cell free supernatant from L. reuteri ATCC 23272 had inhibitory effects on P. larvae KB10 growth and biofilm production due to its acidic nature. The obtained results can be used for antibiotic substitution in AFB control and treatment.},
}
@article {pmid31656155,
year = {2019},
author = {Ielapi, N and Nicoletti, E and Lorè, C and Guasticchi, G and Avenoso, T and Barbetta, A and de Franciscis, S and Andreucci, M and Sapienza, P and Serra, R},
title = {The Role of Biofilm In Central Venous Catheter Related Bloodstream Infections: Evidence Based Nursing And Review of The Literature.},
journal = {Reviews on recent clinical trials},
volume = {},
number = {},
pages = {},
doi = {10.2174/1574887114666191018144739},
pmid = {31656155},
issn = {1876-1038},
abstract = {BACKGROUND: Biofilm is a fundamental component in the pathogenesis of infections related to the use of the central venous catheter (CVC,) which can represent an important health issue in every day practice of nursing and medical staff.<br><br>OBJECTIVE: The objective of the following review is to analyze the components of biofilm and thier role in catheter-related infection determinism in an evidence-based nursing perspective in such a way as to give health professionals useful suggestions in the prevention and management of these complications.<br><br>METHODS: The following databases were consulted for the bibliographic search: Medline, Scopus, Science Direct. Biofilm can be the cause of CVC extraction and can lead to serious haematogenic infectious complications that can increase the morbidity and mortality of affected patients.<br><br>RESULTS: Updated pathophysiologic knowledge of biofilm formation and appropriate diagnostic methodology are pivotal in understanding and detecting CVC-related infections. Lock therapy appears to be a useful, preventive and therapeutic aid in the management of CVC-related infections. New therapies attempting to stop bacterial adhesion on the materials used could represent new frontiers for the prevention of CVC-related infections.<br><br>CONCLUSION: The correct evidence-based nursing methods, based on the use of Guidelines, provides the opportunity to minimize the risks of infection through the implementation of a series of preventive measures both during the CVC positioning phase and in the subsequent phase, meaningly during device management which is performed by medical and nursing staff.},
}
@article {pmid31655088,
year = {2019},
author = {Narmani, A and Teponno, RB and Helaly, SE and Arzanlou, M and Stadler, M},
title = {Cytotoxic, anti-biofilm and antimicrobial polyketides from the plant associated fungus Chaetosphaeronema achilleae.},
journal = {Fitoterapia},
volume = {},
number = {},
pages = {104390},
doi = {10.1016/j.fitote.2019.104390},
pmid = {31655088},
issn = {1873-6971},
abstract = {From extracts of the plant associated fungus Chaetosphaeronema achilleae collected in Iran, a previously unreported isoindolinone named chaetosisoindolinone (1) and a previously undescribed indanone named chaetosindanone (2) were isolated in addition to five known metabolites, 2-(2-acetyl-3,5-dihydroxyphenyl) acetic acid (3), vulculic acid (4), 2-(2-acetyl-3-hydroxy-5-methoxyphenyl)acetic acid (5), curvulin (6), and curvulol (7). Their structures were elucidated on the basis of extensive spectroscopic analysis and high-resolution mass spectrometry. The isolated compounds were tested for their antimicrobial, anti-biofilm, and nematicidal activities. Compound 2 exhibited cytotoxicity against the human breast adenocarcinoma MCF-7 cells with an IC50 value of 1.5 μg/mL. Furthermore, compounds 4 and 7 almost completely inhibited biofilm formation in Staphylococcus aureus at 256 μg/mL. Weak antimicrobial activities were also observed for some of the isolated compounds against Mucor hiemalis, Rhodoturula glutinis, Chromobacterium violaceum, and Staphylococcus aureus.},
}
@article {pmid31654510,
year = {2019},
author = {K Singla, R and K Dubey, A},
title = {Molecules and Metabolites from Natural Products as Inhibitors of Biofilm in Candida spp. pathogens.},
journal = {Current topics in medicinal chemistry},
volume = {},
number = {},
pages = {},
doi = {10.2174/1568026619666191025154834},
pmid = {31654510},
issn = {1873-4294},
abstract = {BACKGROUND: Biofilm is a critical virulence factor associated with the strains of Candida spp. pathogens as it confers significant resistance to the pathogen against antifungal drugs.<br><br>METHODS: A systematic review of the literature was undertaken by focusing on natural products, which have been reported to inhibit biofilms produced by Candida spp. The databases explored were that from PubMed and Google Scholar. The abstracts and full text of the manuscripts from the literature were analyzed and included if found significant.<br><br>REVIEW: Medicinal plants from the order Lamiales, Apiales, Asterales, Myrtales, Sapindales, Acorales, Poales and Laurales were reported to inhibit the biofilms formed by Candida spp. From the microbiological sources, lactobacilli, Streptomyces chrestomyceticus and Streptococcus thermophilus B had shown the strong biofilm inhibition potential. Further, diverse nature of the compounds from classes like terpenoids, phenylpropanoid, alkaloids, flavonoids, polyphenol, naphthoquinone and saponin were found to be significant in inhibiting the biofilm of Candida spp.<br><br>CONCLUSION: Natural products from both plant and microbial origins have proven themselves as goldmine for isolating the potential biofilm inhibitors with specific or multi-locus mechanism of action. Structural and functional characterization of the bioactive molecules from active extracts should be the next line of approach along with the thorough exploration of the mechanism of action for the already identified bioactive molecules.},
}
@article {pmid31653277,
year = {2019},
author = {Gholami, SA and Goli, HR and Haghshenas, MR and Mirzaei, B},
title = {Evaluation of polysaccharide intercellular adhesion (PIA) and glycerol teichoic acid (Gly-TA) arisen antibodies to prevention of biofilm formation in Staphylococcus aureus and Staphylococcus epidermidis strains.},
journal = {BMC research notes},
volume = {12},
number = {1},
pages = {691},
doi = {10.1186/s13104-019-4736-8},
pmid = {31653277},
issn = {1756-0500},
abstract = {OBJECTIVE: Staphylococcus aureus and S. epidermidis as opportunistic pathogens, notable for their frequency and severity of infections are recognized as the most usual reasons for medical device-associated infections that strike hospitalized patients and also immunocompromised individuals. In this study, the polysaccharide intercellular adhesion (PIA) and Glycerol teichoic acid) Gly-TA) as two major macromolecules in the biofilm formation process were purified under the native condition and their structure was analyzed by using colorimetric assays and Fourier Transform Infrared spectroscopy (FTIR). Afterward, the immune response of macromolecules and the mixture of them were assessed by measuring total IgG titers. Subsequently, biofilm inhibitory effects of raising antibodies to biofilm former S. aureus and S. epidermidis were evaluated.<br><br>RESULTS: Obtained data were shown a significant rise in levels of antibodies in immunized mice with mentioned antibodies in comparison with the control group. According to the obtained findings, mentioned antibodies could eliminate S. aureus and S. epidermidis biofilm formation in vitro assays. This survey confirms the proposal that immunization of mice with a mixture of Gly-TA and PIA vaccine could be secure and protected against S. epidermidis and S. aureus infection.},
}
@article {pmid31652836,
year = {2019},
author = {Choi, JS and Lee, JW and Shin, UC and Lee, MW and Kim, DJ and Kim, SW},
title = {Inhibitory Activity of Silver Nanoparticles Synthesized Using Lycopersicon Esculentum against Biofilm Formation in Candida Species.},
journal = {Nanomaterials (Basel, Switzerland)},
volume = {9},
number = {11},
pages = {},
doi = {10.3390/nano9111512},
pmid = {31652836},
issn = {2079-4991},
support = {P0006675//Ministry of Trade, Industry and Energy(MOTIE) and Korea Institute for Advancement of Technology(KIAT)/ ; },
abstract = {This paper investigated the antifungal and antibiofilm activity of silver nanoparticles synthesized with Lycopersicon esculentum extracts against Candida species. Lycopersicon esculentum extracts obtained by homogenization were mixed with silver nitrate to synthesize silver nanoparticles. Analysis of the particle characteristics by UV-Vis spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FT-IR) confirmed that the Lycopersicon esculentum extracts effectively served as reductants and capping agents. Minimum inhibitory concentration (MIC) tests were conducted to confirm antifungal activity against Candida species. In all the tested species, the silver nanoparticles inhibited the growth of Candida. Moreover, the SEM images of Candida species treated with silver nanoparticles synthesized using natural extracts of Lycopersicon esculentum showed that silver nanoparticles adhered to the surface of Candida, which induced pore formation in the membranes and prevented their normal growth. Ultimately, these abnormal forms of Candida were thought to be less able to form biofilms than normal Candida. The antifungal and antibiofilm activities of silver nanoparticles against Candida are expected to be utilized in various fields and contribute in particular to developments in nanomedicine.},
}
@article {pmid31652575,
year = {2019},
author = {Maletskyi, Z and Zigta, DK and Kulesha, O and Ratnaweera, H},
title = {Chemical Enhancement for Retrofitting Moving Bed Biofilm and Integrated Fixed Film Activated Sludge Systems into Membrane Bioreactors.},
journal = {Membranes},
volume = {9},
number = {10},
pages = {},
doi = {10.3390/membranes9100135},
pmid = {31652575},
issn = {2077-0375},
abstract = {Positive effects of retrofitting MBBR and IFAS systems into MBRs can be exploited by introducing chemical enhancement applying coagulants in the membrane separation step. The current study reports basic principles of chemical enhancement with aluminium sulphate coagulant in biofilm-MBR (Bf-MBR) based on results of total recycle tests performed at different dosages of the chemical enhancer and properties characterization of filtrates, supernatants and sediments. It demonstrates a possibility to achieve lower membrane fouling rates with dosing of aluminium sulphate coagulant into MBBR and IFAS mixed liquors by extending operational cycles by 20 and 80 time respectively as well as increasing operating permeability of membrane separation by 1.3 times for IFAS. It has been found that charge neutralization is the dominating mechanism of aluminium sulphate action as a chemical enhancer in Bf-MBR, however, properties of the membrane surface influencing charge repulsion of foulants should be considered together with the secondary ability of the coagulant to improve consolidation of sediments.},
}
@article {pmid31652188,
year = {2019},
author = {Ferlic, PW and Liebensteiner, M and Nogler, M and Weinberg, A and Kühn, KD and Coraça-Huber, DC},
title = {Increased Staphylococcus aureus biofilm formation on biodegradable PHB-implants compared to conventional orthopedic implants: an in vitro analysis.},
journal = {Journal of orthopaedic trauma},
volume = {},
number = {},
pages = {},
doi = {10.1097/BOT.0000000000001674},
pmid = {31652188},
issn = {1531-2291},
abstract = {OBJECTIVE: To compare the biofilm formation on a biodegradable material, poly(3-hydroxybutyrate) (PHB), to that on conventional titanium (Ti) and steel (St) implant material.<br><br>METHODS: Pins made of the different materials were incubated in Müller-Hinton broth inoculated with 2 x 10 CFU mL-1 of S. aureus for 2 and 7 days and then sonicated for the disruption of the biofilms. Colony forming units (CFU) were counted to quantify the number of bacteria in the biofilm and the cell proliferation assay XTT was used to evaluate their metabolic activity. Scanning electron microscopy (SEM) visualized the structure of the biofilm.<br><br>RESULTS: We found a significantly higher metabolic activity and CFU count in the biofilm of PHB pins compared to St and Ti (ANOVA p<0.0001). SEM revealed structured biofilms on PHB pins already after 2 days of incubation, which was not observed on the other tested implants.<br><br>CONCLUSION: PHB implants seem to provide an environment that advantages the formation of biofilms of S. aureus, a common pathogen in implant related infections. The amount of biofilm is higher on PHB compared to conventionally used orthopedic titanium and steel implants. To overcome the potential risk of surgical site infections linked to the clinical use of PHB implants, possible modifications of the material, increasing its antibacterial properties, need to be further investigated.},
}
@article {pmid31651349,
year = {2019},
author = {Lee, S and Hwang, J and Kim, J and Lee, J and Kim, HC and Rhim, H and Han, JI},
title = {Biofilm production of coagulase-negative staphylococci isolated from rescued wild animals in the Republic of Korea.},
journal = {Acta veterinaria Scandinavica},
volume = {61},
number = {1},
pages = {50},
doi = {10.1186/s13028-019-0485-x},
pmid = {31651349},
issn = {1751-0147},
support = {2016R1D1A3B03932480//National Research Foundation of Korea/ ; 2016000210002//ministry of envirionment korea/ ; },
abstract = {Biofilm production is a well-known causative factor of catheter- and medical device-related sepsis. Its high prevalence in coagulase-negative staphylococci (CoNS) has recently been reported. Information on biofilm production in CoNS isolated from wild animals is lacking. Herein, we studied the biofilm formation capabilities of CoNS isolated from rescued wild animals in the Republic of Korea. Swab samples were collected from the conjunctiva, nasal cavity, perianal area, and rectum for mammals while the sampling was done from the conjunctiva, oral mucosa, pericloacal area, and cloaca for birds. Isolation of CoNS was based on morphological and biochemical analyses along with molecular typing. Biofilm production was analyzed using 96-well plate based quantitative adherence assays. The studies demonstrated that CoNS of mammalian origin have higher biofilm-producing ability (70.4%) than the isolates from birds (62.5%). In particular, all methicillin-resistant (MR) CoNS isolated from mammals were capable of biofilm formation while only 63.3% of MR CoNS isolated from birds could produce biofilms. The MR CoNS isolated from mammals also had a significantly higher ability to form biofilms (100%) than methicillin susceptible CoNS (60.0%) than those isolates from birds. The findings show that wild animals may act as reservoirs as well as possible transmitters of biofilm-mediated antibiotic resistant genes.},
}
@article {pmid31649642,
year = {2019},
author = {Tan, F and She, P and Zhou, L and Liu, Y and Chen, L and Luo, Z and Wu, Y},
title = {Bactericidal and Anti-biofilm Activity of the Retinoid Compound CD437 Against Enterococcus faecalis.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2301},
doi = {10.3389/fmicb.2019.02301},
pmid = {31649642},
issn = {1664-302X},
abstract = {Enterococcus faecalis (E. faecalis), a biofilm-forming pathogen, causes nosocomial infections. In recent years, drug resistance by enterococci has become increasingly severe due to widespread antibiotic abuse. Therefore, novel antibacterial agents are urgently needed. In this study, the synthetic retinoid compound CD437 was found to have potent bactericidal effect on E. faecalis. In addition, CD437 exhibited synergistic effects when administered in combination with gentamicin and additive effects when combined with ceftriaxone sodium. CD437 also inhibited biofilm formation by E. faecalis and exerted bactericidal effect on mature biofilm. Moreover, CD437 exhibited antibacterial and anti-biofilm effects against Staphylococcus. No bactericidal action of CD437 was observed against the gram-negative bacillus, but Pseudomonas aeruginosa biofilm extracellular polymeric substances (EPS) matrix formation was reduced. Overall, these findings indicate that CD437 has the potential to be developed as a novel antibacterial drug.},
}
@article {pmid31648793,
year = {2019},
author = {Park, JW and An, JS and Lim, WH and Lim, BS and Ahn, SJ},
title = {Microbial changes in biofilms on composite resins with different surface roughness: An in vitro study with a multispecies biofilm model.},
journal = {The Journal of prosthetic dentistry},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.prosdent.2019.08.009},
pmid = {31648793},
issn = {1097-6841},
abstract = {STATEMENT OF PROBLEM: The single-species biofilm method cannot represent the interaction and complex functions of microorganisms associated with oral biofilms.<br><br>PURPOSE: The purpose of this in vitro study was to investigate microbial changes in biofilms on composite resins of varying surface roughness by using a multispecies biofilm model with early-colonizing streptococci, middle colonizer, and late-colonizing gram-negative anaerobes.<br><br>MATERIAL AND METHODS: Composite resin disks were prepared with different roughness: SR180, SR400, SR1500, and SRGlass roughened with 180-, 400-, and 1500-grit silicon carbide paper and glass (control surface without surface roughening). Surface roughness was analyzed by confocal laser scanning and scanning electron microscopy. After multispecies biofilms had been grown on the composite resin surfaces, the adhesion of Streptococcus mutans, Streptococcus sobrinus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and of total bacteria was determined after 1 (T1) and 4 (T2) days. Differences in surface roughness among the 4 groups were tested with 1-way ANOVA. Multifactorial analysis of variance was used to determine the time-related differences in the bacterial composition with respect to surface roughness (α=.05).<br><br>RESULTS: The order of SR, from highest to lowest, was SR180 (1.45 ±0.11 μm), SR400 (0.62 ±0.05 μm), SR1500 (0.35 ±0.02 μm), and SRGlass (0.15 ±0.01 μm) (SR180>SR400>SR1500>SRGlass, P<.001). Increased surface roughness was not proportional to bacterial adhesion. Significant differences in the adhesion of total bacteria was only found between SRGlass and SR180 (SR180>SRGlass, P=.029). The adhesion of S. mutans and S. sobrinus to SR180 and SR400 was higher than that to SRGlass (SR180=SR400>SRGlass; S. mutans, P=.003; S. sobrinus, P=.002). However, the adhesion of A. actinomycetemcomitans and P. gingivalis to composite resin was not significantly influenced by surface roughness. Adhesion of total bacteria, S. mutans, and S. sobrinus increased from T1 to T2 (T1<T2, P<.001), whereas the adhesion of periodontal pathogens decreased from T1 to T2 (T1>T2; A. actinomycetemcomitans, P<.001; P. gingivalis, P=.013).<br><br>CONCLUSIONS: Decreased adhesion of cariogenic streptococci and total bacteria was observed at surface roughness values of around 0.15 μm. Periodic finishing of surface roughness should be considered to minimize the adhesion of cariogenic streptococci to composite resin surfaces.},
}
@article {pmid31647407,
year = {2019},
author = {Sugathan, S and Mandal, J},
title = {An invitro experimental study of the effect of fosfomycin in combination with amikacin, ciprofloxacin or meropenem on biofilm formation by multidrug-resistant urinary isolates of Escherichia coli.},
journal = {Journal of medical microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1099/jmm.0.001061},
pmid = {31647407},
issn = {1473-5644},
abstract = {Background. This study was conducted to understand the effect of fosfomycin in combination with amikacin, ciprofloxacin or meropenem on biofilm formation by multidrug-resistant urinary isolates of Escherichia coli.Methods. Fifty urinary tract multidrug-resistant E. coli isolates that were known biofilm producers were studied. The MIC was determined using the agar dilution method for amikacin, ciprofloxacin, meropenem and fosfomycin. The fractional inhibitory concentration was determined for the combination of antibiotics followed by a time-kill assay. A tissue culture plate method was used to study the effect of the combination of antibiotics on biofilm formation.Results. The MICs of the isolates tested ranged from 0.25 to 32 µg ml-1 for fosfomycin, 1 to 1024 µg ml-1 for ciprofloxacin, 4 to 1024 µg ml-1 for amikacin, and 0.25 to 512 µg ml-1 for meropenem. The combination of fosfomycin with meropenem showed 68 % synergy, fosfomycin with amikacin 58 % synergy and fosfomycin with ciprofloxacin 6 % synergy. The combination also reduced the MIC of each antibiotic and none showed an antagonistic effect. Biofilm inhibition was best observed with the combination of fosfomycin with meropenem.Conclusion. The combination of fosfomycin with amikacin and fosfomycin with meropenem yielded a high percentage of synergy alongside an increased capacity to reduce biofilm formation when compared to combination with ciprofloxacin against multidrug-resistant E. coli. Fosfomycin in combination with other classes of antimicrobial agents has potential beneficial effects.},
}
@article {pmid31646898,
year = {2019},
author = {Alvim, DCSS and Ferreira, AFM and Leal, MA and Oliveira, LMA and Botelho, AMN and Botelho, ACN and Figueiredo, AMS and Fracalanzza, SEL and Teixeira, LM and Pinto, TCA},
title = {Biofilm production and distribution of pilus variants among Streptococcus agalactiae isolated from human and animal sources.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-7},
doi = {10.1080/08927014.2019.1678592},
pmid = {31646898},
issn = {1029-2454},
abstract = {Streptococcus agalactiae (group B Streptococcus, GBS) is a major pathogen in humans and animals. Pili and biofilm may be important virulence factors in this bacterial species. Here, biofilm production and the distribution of pilus variants among 134 GBS isolates from human and animal sources were evaluated. Biofilm production was significantly enhanced in 1% glucose-supplemented medium (p < 0.05). Using this medium, most GBS strains were strong biofilm producers. Biomass was mainly composed of proteins, followed by extracellular DNA, while polysaccharides represented a minor portion. All GBS strains presented at least one pilus variant. PI-2a was the most common among human GBS while PI-2b was the most common among animal isolates. Human GBS harboring PI-2b and animal GBS harboring PI-2a presented significantly reduced biofilm production (p = 0.0033). In conclusion, strong biofilm production seems to be a common characteristic in GBS, and association of the clinical source with the pilus variant may be crucial for this.},
}
@article {pmid31646225,
year = {2019},
author = {Saigal, and Irfan, M and Khan, P and Abid, M and Khan, MM},
title = {Design, Synthesis, and Biological Evaluation of Novel Fused Spiro-4H-Pyran Derivatives as Bacterial Biofilm Disruptor.},
journal = {ACS omega},
volume = {4},
number = {16},
pages = {16794-16807},
doi = {10.1021/acsomega.9b01571},
pmid = {31646225},
issn = {2470-1343},
abstract = {This study aims to synthesize novel fused spiro-4H-pyran derivatives under green conditions to develop agents having antimicrobial activity. The synthesized compounds were initially screened for in vitro antibacterial activity against two Gram-positive and three Gram-negative bacterial strains, and all the compounds exhibited moderate to potent antibacterial activity. However, compound 4l showed significant inhibition toward all the bacterial strains, particularly against Streptococcus pneumoniae and Escherichia coli with minimum inhibitory concentration values of 125 μg/mL for each. The toxicity studies of selected compounds (4c, 4e, 4l, and 4m) using human red blood cells as well as human embryonic kidney (HEK-293) cells showed nontoxic behavior at desired concentration. Growth kinetic and time-kill curve studies of 4l against S. pneumoniae and E. coli supported its bactericidal nature. Interestingly, compound 4l showed a synergistic effect when used in combination with ciprofloxacin against selected strains. Biofilm formation in the presence of a lead compound, as assessed by XTT assay, showed complete disruption of the bacterial biofilm visualized by scanning electron microscopy. Overall, the findings suggest 4l to be considered as a promising lead for further development as an antibacterial agent.},
}
@article {pmid31646145,
year = {2019},
author = {Aliramezani, A and Soleimani, M and Fard, RMN and Nojoomi, F},
title = {Virulence determinants and biofilm formation of Acinetobacter baumannii isolated from hospitalized patients.},
journal = {Germs},
volume = {9},
number = {3},
pages = {148-153},
doi = {10.18683/germs.2019.1171},
pmid = {31646145},
issn = {2248-2997},
abstract = {Introduction: Acinetobacter baumannii are nosocomial bacteria that are responsible for outbreaks and severe infections in hospitalized patients globally. The major target of this study was the characterization of virulence determinants and biofilm formation of A. baumannii isolates from hospitalized patients.<br><br>Methods: In total, 100 A. baumannii were collected from three hospitals in Tehran, Iran, 2017-2018. The isolates were assessed using phenotypic and genotypic methods and then screened for virulence factor encoding genes such as plcN and lasB using conventional polymerase chain reaction. Furthermore, bacterial biofilm formation, motility and hemolytic and proteolytic activities were assessed.<br><br>Results: Of 100 A. baumannii isolates, 20 isolates included plcN and four isolates included lasB using PCR assay. Overall, 21 isolates were negative for biofilm formation while 45, 20 and 14 of the total isolates were reported as weak, moderate and strong biofilm producers, respectively. All isolates were positive for bap genes using PCR. Moreover, 35 isolates were motile on Luria-Bertani media, 47 isolates were α-hemolytic on Brucella blood agar media and all isolates displayed proteolytic activity.<br><br>Conclusions: Healthcare-associated infections with A. baumannii are a major concern, importantly due to their potency to acquire virulence factor genes. Therefore, shedding light in the discovery of new antimicrobial and/or therapeutic agents against virulent A. baumannii strains seem to be necessary.},
}
@article {pmid31646012,
year = {2019},
author = {Masters, EA and Trombetta, RP and de Mesy Bentley, KL and Boyce, BF and Gill, AL and Gill, SR and Nishitani, K and Ishikawa, M and Morita, Y and Ito, H and Bello-Irizarry, SN and Ninomiya, M and Brodell, JD and Lee, CC and Hao, SP and Oh, I and Xie, C and Awad, HA and Daiss, JL and Owen, JR and Kates, SL and Schwarz, EM and Muthukrishnan, G},
title = {Evolving concepts in bone infection: redefining &quot;biofilm&quot;, &quot;acute vs. chronic osteomyelitis&quot;, &quot;the immune proteome&quot; and &quot;local antibiotic therapy&quot;.},
journal = {Bone research},
volume = {7},
number = {},
pages = {20},
doi = {10.1038/s41413-019-0061-z},
pmid = {31646012},
issn = {2095-4700},
abstract = {Osteomyelitis is a devastating disease caused by microbial infection of bone. While the frequency of infection following elective orthopedic surgery is low, rates of reinfection are disturbingly high. Staphylococcus aureus is responsible for the majority of chronic osteomyelitis cases and is often considered to be incurable due to bacterial persistence deep within bone. Unfortunately, there is no consensus on clinical classifications of osteomyelitis and the ensuing treatment algorithm. Given the high patient morbidity, mortality, and economic burden caused by osteomyelitis, it is important to elucidate mechanisms of bone infection to inform novel strategies for prevention and curative treatment. Recent discoveries in this field have identified three distinct reservoirs of bacterial biofilm including: Staphylococcal abscess communities in the local soft tissue and bone marrow, glycocalyx formation on implant hardware and necrotic tissue, and colonization of the osteocyte-lacuno canalicular network (OLCN) of cortical bone. In contrast, S. aureus intracellular persistence in bone cells has not been substantiated in vivo, which challenges this mode of chronic osteomyelitis. There have also been major advances in our understanding of the immune proteome against S. aureus, from clinical studies of serum antibodies and media enriched for newly synthesized antibodies (MENSA), which may provide new opportunities for osteomyelitis diagnosis, prognosis, and vaccine development. Finally, novel therapies such as antimicrobial implant coatings and antibiotic impregnated 3D-printed scaffolds represent promising strategies for preventing and managing this devastating disease. Here, we review these recent advances and highlight translational opportunities towards a cure.},
}
@article {pmid31642854,
year = {2019},
author = {Chen, L and Yang, D and Feng, J and Zhang, M and Qian, Q and Zhou, Y},
title = {Switchable modulation of bacterial growth and biofilm formation based on supramolecular tripeptide amphiphiles.},
journal = {Journal of materials chemistry. B},
volume = {7},
number = {41},
pages = {6420-6427},
doi = {10.1039/c9tb00973f},
pmid = {31642854},
issn = {2050-7518},
abstract = {Design and fabrication of smart supramolecular peptide systems is an effective strategy to develop antibacterial agents that can be selectively activated/inactivated by external stimuli for combating bacterial resistance. In this work, we selectively synthesized isomeric tripeptides (i.e., Ala-Gly-Gly-OH and Gly-Gly-Ala-OH) with the simplest structures to construct a minimalistic dual-responsive supramolecular antibacterial system. To impart stimuli-responsiveness, the tripeptides were modified using a hydrophobic n-butylazobenzene tail at the N-terminal, which benefited the enhancement of the hydrophobicity of the tripeptides and they served as synergistic antibacterial moieties. Two different self-assembled 1-D morphologies (i.e., nanotwists and nanofibers) were observed under the same conditions when the position of the Ala residue was altered. More importantly, the supramolecular tripeptide amphiphiles exhibited a reversible assembly/disassembly process in response to different stimuli (i.e., light and host-guest chemistry). Based on the stimuli-responsiveness, the antibacterial/antibiofilm activities against either Gram-negative or Gram-positive bacteria could be reversibly modulated.},
}
@article {pmid31642039,
year = {2019},
author = {Ortega-Peña, S and Martínez-García, S and Rodríguez-Martínez, S and Cancino-Diaz, ME and Cancino-Diaz, JC},
title = {Overview of Staphylococcus epidermidis cell wall-anchored proteins: potential targets to inhibit biofilm formation.},
journal = {Molecular biology reports},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11033-019-05139-1},
pmid = {31642039},
issn = {1573-4978},
support = {20181167//SIP-Instituto Politécnico Nacional Mexico/ ; },
abstract = {Currently, the treatment of infections by Staphylococcus epidermidis (S. epidermidis) represents a challenge because some strains have multidrug-resistance to antimicrobial products (antibiotic and biocides) and can produce biofilms. These biofilms protect bacterial cells from both antimicrobials and the host immune response. Therefore, it is crucial to encourage research on the development of new treatments. One method is immunotherapy, targeting components of S. epidermidis, such as S. epidermidis surface (Ses) proteins. Ses is expressed constitutively in most strains, and they participate in biofilm formation. This review is an update on Ses, regarding their structure, biological function, their relationship with S. epidermidis biofilm formation, and its possible role as therapeutic targets to develop immunotherapeutic treatments to prevent infections by S. epidermidis.},
}
@article {pmid31641666,
year = {2019},
author = {Raya, S and Belbase, A and Dhakal, L and Govinda Prajapati, K and Baidya, R and Kishor Bimali, N},
title = {In-Vitro Biofilm Formation and Antimicrobial Resistance of Escherichia coli in Diabetic and Nondiabetic Patients.},
journal = {BioMed research international},
volume = {2019},
number = {},
pages = {1474578},
doi = {10.1155/2019/1474578},
pmid = {31641666},
issn = {2314-6141},
abstract = {Background: Diabetic patients are more susceptible to urinary tract infection compared to nondiabetic patients, Escherichia coli being the most common uropathogen causing UTI. Unreasonable and incorrect antibiotic prescription for UTI in these patients may induce the development of antibiotic-resistant urinary pathogens resulting in delayed recovery and longer hospitalization. In addition to these, biofilm forming capacity of the pathogen may worsen the problem. The main aim of this cross-sectional study (conducted from March to September 2015) is to detect the biofilm forming capacity of UTI causing micro-organisms and compare the antibiotic resistance pattern of Escherichia coli, the most common cause of UTI, which will help the physician in choosing the best antibiotic.<br><br>Method: Total of 1,099 clean-catch mid stream urine (CCMSU) was processed by standard microbiological technique; 182 were from the diabetic group and 917 nondiabetic. Following identification, all isolates were subjected to antibiotic susceptibility testing using modified Kirby-Bauer disc diffusion method. In-vitro biofilm forming capacity of the isolates were detected by Microtitre plate method. The data were analyzed using SPSS software 16.<br><br>Result: Urinary tract infection was found to be significantly higher in diabetic patients (42.9%) compared to nondiabetic patients (17.4%) with Escherichia coli as the most common uropathogen in both diabetic and nondiabetic groups. Similarly, UTI was more common in elderly population (29.5%). Imipenem, nitrofurantoin and amikacin were found to be the most effective drug for uropathogenic E. coli in both diabetic and nondiabetic patients, whereas amoxicillin, ciprofloxacin, and cotrimoxazole were least effective. Of the total bacterial isolates, 43.3% showed positive results for in-vitro biofilm production by the Microtitre plate method. A significantly higher resistance rate was observed among biofilm producing E. coli for quinolones, cotrimoxazole, and third generation cephalosporin ceftriaxone. Most of the biofilm producers (79.5%) were found to be MDR (p-value 0.015).<br><br>Conclusion: Elderly populations with diabetes are at a higher risk of UTI. Higher biofilm production and resistance to in-use antimicrobial agents in this study render its inefficacy for empirical treatment and point out the importance of biofilm screening to ensure the effective management of infection.},
}
@article {pmid31638894,
year = {2019},
author = {Di Domenico, EG and Rimoldi, SG and Cavallo, I and D'Agosto, G and Trento, E and Cagnoni, G and Palazzin, A and Pagani, C and Romeri, F and De Vecchi, E and Schiavini, M and Secchi, D and Antona, C and Rizzardini, G and Dichirico, RB and Toma, L and Kovacs, D and Cardinali, G and Gallo, MT and Gismondo, MR and Ensoli, F},
title = {Microbial biofilm correlates with an increased antibiotic tolerance and poor therapeutic outcome in infective endocarditis.},
journal = {BMC microbiology},
volume = {19},
number = {1},
pages = {228},
doi = {10.1186/s12866-019-1596-2},
pmid = {31638894},
issn = {1471-2180},
abstract = {BACKGROUND: Infective endocarditis (IE) is associated with high rates of mortality. Prolonged treatments with high-dose intravenous antibiotics often fail to eradicate the infection, frequently leading to high-risk surgical intervention. By providing a mechanism of antibiotic tolerance, which escapes conventional antibiotic susceptibility profiling, microbial biofilm represents a key diagnostic and therapeutic challenge for clinicians. This study aims at assessing a rapid biofilm identification assay and a targeted antimicrobial susceptibility profile of biofilm-growing bacteria in patients with IE, which were unresponsive to antibiotic therapy.<br><br>RESULTS: Staphylococcus aureus was the most common isolate (50%), followed by Enterococcus faecalis (25%) and Streptococcus gallolyticus (25%). All microbial isolates were found to be capable of producing large, structured biofilms in vitro. As expected, antibiotic treatment either administered on the basis of antibiogram or chosen empirically among those considered first-line antibiotics for IE, including ceftriaxone, daptomycin, tigecycline and vancomycin, was not effective at eradicating biofilm-growing bacteria. Conversely, antimicrobial susceptibility profile of biofilm-growing bacteria indicated that teicoplanin, oxacillin and fusidic acid were most effective against S. aureus biofilm, while ampicillin was the most active against S. gallolyticus and E. faecalis biofilm, respectively.<br><br>CONCLUSIONS: This study indicates that biofilm-producing bacteria, from surgically treated IE, display a high tolerance to antibiotics, which is undetected by conventional antibiograms. The rapid identification and antimicrobial tolerance profiling of biofilm-growing bacteria in IE can provide key information for both antimicrobial therapy and prevention strategies.},
}
@article {pmid31637837,
year = {2019},
author = {Røder, HL and Olsen, NMC and Whiteley, M and Burmølle, M},
title = {Unraveling interspecies interactions across heterogeneities in complex biofilm communities.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.14834},
pmid = {31637837},
issn = {1462-2920},
abstract = {The importance of microbial biofilms has been well-recognized for several decades, and focus is now shifting towards investigating multi-species biofilm communities rather than mono- or dual-species biofilms. Therefore, the demand for techniques that provide a sufficient amount of information at adequate resolution is increasing. One major challenge for multi-species studies is that diversity and spatial organization often lead to a high degree of spatial and chemical heterogeneity. Many current approaches do not account for such heterogeneity and therefore only result in diluted or single scale information (-omics techniques in particular), which could obscure important information about the community. Here, we bring attention to the issues of heterogeneity when analyzing synthetic multi-species biofilms, in vitro, and the importance of multi-scale approaches. We provide an overview of current and newer approaches that can be applied to biofilm communities, in order to elucidate interactions at the appropriate scale. This article is protected by copyright. All rights reserved.},
}
@article {pmid31637462,
year = {2019},
author = {Birarda, G and Delneri, A and Lagatolla, C and Parisse, P and Cescutti, P and Vaccari, L and Rizzo, R},
title = {Multi-technique microscopy investigation on bacterial biofilm matrices: a study on Klebsiella pneumoniae clinical strains.},
journal = {Analytical and bioanalytical chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00216-019-02111-7},
pmid = {31637462},
issn = {1618-2650},
support = {FRA15//University of Trieste/ ; },
abstract = {Biofilms are communities of bacteria living embedded in a highly hydrated matrix composed of polysaccharides, proteins, and extracellular DNA. This life style confers numerous advantages to bacteria including protection against external threats. However, they also contribute to increase bacterial resistance against antimicrobials, an issue particularly relevant in dangerous infections. Due to the complexity of the matrix, few information is present in the literature on details of its architecture including the spatial distribution of the macromolecular components which might give hints on the way the biofilm scaffold is built up by bacteria. In this study, we investigated the possibility to combine well-established microbiological procedures with advanced microscopies to get information on composition and distribution of the macromolecular components of biofilm matrices. To this, confocal microscopy, diffraction-limited infrared (IR) spectral imaging, and atomic force microscopy (AFM) were used to explore biofilm produced by a clinical strain of Klebsiella pneumoniae. IR imaging permitted to have clues on how the biofilm grows and spreads on surfaces, and the local distribution of the components within it. Through the analysis of the pure component spectra, it was possible to assess the chemical and structural composition of the saccaridic matrix, confirming the data obtained by NMR. It was also possible to follow the time course of biofilm from 6 up to 48 h when the biofilm grew into a 3-dimensional multi-layered structure, characteristic of colonies of bacteria linked together by a complex matrix. In addition, nanoFTIR and AFM investigations allowed the estimation of biofilm growth in the vertical direction and the morphological analysis of bacterial colonies at different time points and the evaluation of the chemical composition at the nanoscale.},
}
@article {pmid31635733,
year = {2020},
author = {Jung, J and Bae, Y and Kwan Cho, Y and Ren, X and Sun, Y},
title = {Structural insights into conformation of amphiphilic quaternary ammonium chitosans to control fungicidal and anti-biofilm functions.},
journal = {Carbohydrate polymers},
volume = {228},
number = {},
pages = {115391},
doi = {10.1016/j.carbpol.2019.115391},
pmid = {31635733},
issn = {1879-1344},
abstract = {Fungal biofilm formation is an emerging problem in a wide range of health-related applications. This study aims to design and synthesize amphiphilic quaternary ammonium chitosans (AQACs) that could bind onto fungal biofilms to kill adherent fungal cells, and establish their structural/fungicidal activity relationships. AQACs with different hydrophobic alkyl chain length (C4, C8, and C12) were synthesized by quaternization of 3-bromopropionic acid with the corresponding tertiary amines, followed by reacting with chitosan using the EDC/NHS chemistry. The new AQACs were soluble in water, yet formed self-aggregates in the solution with different sizes. In antifungal tests against free-floating Candida albicans, shorter alkyl chains (C4) in the AQACs resulted in the most potent fungicidal effect. However, in the treatment of Candida biofilms formed on solid surfaces, AQACs with longer alkyl chains (C8 and C12) were much more effective than their shorter chain counterpart (C4). The effects of alkyl chain self-aggregation on the opposite trend in fungicidal and anti-biofilm activities were discussed. All the AQACs showed excellent cytocompatibility with mammalian cells.},
}
@article {pmid31634700,
year = {2019},
author = {Sun, Y and Lang, Y and Yan, Z and Wang, L and Zhang, Z},
title = {High-throughput sequencing analysis of marine pioneer surface-biofilm bacteria communities on different PDMS-based coatings.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {185},
number = {},
pages = {110538},
doi = {10.1016/j.colsurfb.2019.110538},
pmid = {31634700},
issn = {1873-4367},
abstract = {Marine biofilms, the attachment of marine microorganisms on artificial surfaces in natural seawater, play critical roles in the development of marine biofouling, which pave ways for the settlement and colonization of sessile invertebrate larvae. Despite the excellent microbe-inhibitory effect of polydimethylsiloxane (PDMS)-based coatings, marine bacteria could still attach to surfaces and form natural biofilms. However, there is little information available on the common structural features of pioneer surface-biofilm bacteria (PSB) communities on different PDMS-based coatings with regard to their compositions, distributions and diversity. Herein, the present study aims to explore the compositional and structural features of the PSB communities on different PDMS-based coatings using 16S rRNA gene amplicon sequencing in terms of the taxonomic structures at phylum, family and genus level. The results revealed the PSB communities on different PDMS-based coatings possessed high similarities in compositional, structural and diversity features, but varied greatly in relative abundance and distributions. Proteobacteria was the most diverse and overwhelming phylum in biofilms formed on all PDMS-based coatings, followed by Cyanobacteria. In addition, the decreased abundance of Proteobacteria and the increased abundance of Cyanobacteria on the carbon nanotubes (CNTs)-modifed PDMS composites (CPCs) may contribute to their differential anti-biofouling effect against the colonization of juvenile macrofoulers.},
}
@article {pmid31632948,
year = {2019},
author = {Walsh, DJ and Livinghouse, T and Goeres, DM and Mettler, M and Stewart, PS},
title = {Antimicrobial Activity of Naturally Occurring Phenols and Derivatives Against Biofilm and Planktonic Bacteria.},
journal = {Frontiers in chemistry},
volume = {7},
number = {},
pages = {653},
doi = {10.3389/fchem.2019.00653},
pmid = {31632948},
issn = {2296-2646},
abstract = {Biofilm-forming bacteria present formidable challenges across diverse settings, and there is a need for new antimicrobial agents that are both environmentally acceptable and relatively potent against microorganisms in the biofilm state. The antimicrobial activity of three naturally occurring, low molecular weight, phenols, and their derivatives were evaluated against planktonic and biofilm Staphylococcus epidermidis and Pseudomonas aeruginosa. The structure activity relationships of eugenol, thymol, carvacrol, and their corresponding 2- and 4-allyl, 2-methallyl, and 2- and 4-n-propyl derivatives were evaluated. Allyl derivatives showed a consistent increased potency with both killing and inhibiting planktonic cells but they exhibited a decrease in potency against biofilms. This result underscores the importance of using biofilm assays to develop structure-activity relationships when the end target is biofilm.},
}
@article {pmid31632023,
year = {2019},
author = {Fang, JY and Lin, YK and Wang, PW and Alalaiwe, A and Yang, YC and Yang, SC},
title = {The Droplet-Size Effect Of Squalene@cetylpyridinium Chloride Nanoemulsions On Antimicrobial Potency Against Planktonic And Biofilm MRSA.},
journal = {International journal of nanomedicine},
volume = {14},
number = {},
pages = {8133-8147},
doi = {10.2147/IJN.S221663},
pmid = {31632023},
issn = {1178-2013},
abstract = {Background: It is important to explore the interaction between antibacterial nanoparticles and microbes for understanding bactericidal activity and developing novel applications. It is possible that the nanoparticulate size can govern the antibacterial potency.<br><br>Purpose: The purpose of this study was to evaluate the antimicrobial and antibiofilm properties of cetylpyridinium chloride (CPC)-decorated nanoemulsions against methicillin-resistant Staphylococcus aureus (MRSA).<br><br>Methods: The droplet size could be adjusted by varying the percentage of squalene, the main ingredient of the oily core.<br><br>Results: We fabricated cationic nanoemulsions of three different sizes, 55, 165, and 245 nm. The nanoemulsions showed greater storage stability than the self-assembled CPC micelles. The tested nanoemulsions exhibited more antimicrobial activity against Gram-positive bacteria than Gram-negative bacteria and fungi. The killing of MRSA was mainly induced by direct cell-membrane damage. This rupture led to the leakage of cytoplasmic DNA and proteins. The nanoemulsions might also degrade the DNA helix and disturb protein synthesis. The proteomic analysis indicated the significant downregulation of DNA-directed RNA polymerase (RNAP) subunits β and β'. The antibacterial effect of nanoemulsions increased with decreasing droplet size in the biofilm MRSA but not planktonic MRSA. The small-sized nanoemulsions had potent antibiofilm activity that showed a colony-forming unit (CFU) reduction of 10-fold compared with the control. The loss of total DNA concentration also negatively correlated with the nanoemulsion size.<br><br>Conclusion: The present report established a foundation for the development of squalene@CPC nanosystems against drug-resistant S. aureus.},
}
@article {pmid31631801,
year = {2019},
author = {Sun, F and Yuan, Q and Wang, Y and Cheng, L and Li, X and Feng, W and Xia, P},
title = {Sub-minimum inhibitory concentration ceftazidime inhibits Escherichia coli biofilm formation by influencing the levels of the ibpA gene and extracellular indole.},
journal = {Journal of chemotherapy (Florence, Italy)},
volume = {},
number = {},
pages = {1-8},
doi = {10.1080/1120009X.2019.1678913},
pmid = {31631801},
issn = {1973-9478},
abstract = {Escherichia coli is a common pathogen of bacterial biofilm infections. Sub-minimum inhibitory concentration ceftazidime (sub-MIC CAZ) could inhibit the biofilm formation of E. coli. Deletion of the ibpAB genes could increase the extracellular indole concentration of E. coli and then inhibit biofilm formation. Therefore, we speculated that sub-MIC CAZ might inhibit biofilm formation via ibpAB. In this study, the results showed that sub-MIC CAZ could significantly inhibit biofilm formation, swimming motility and the expression of the ibpA gene, while it could increase the expression of tnaA gene and extracellular indole concentration. Knockout of the ibpA gene resulted in a decrease in biofilm formation and swimming motility and an increase in the indole concentration. When treated with sub-MIC CAZ, the tnaA gene expression, indole concentration, biofilm formation and swimming motility of MG1655 ΔibpA were similar to those of the control group. The results indicated that sub-MIC CAZ might inhibit the biofilm formation of E. coli by increasing the extracellular indole concentration and downregulating the ibpA gene.},
}
@article {pmid31631600,
year = {2019},
author = {Pu, QK and Liu, SJ and Huang, H and Xiong, JF and Zhnang, L and Fang, Z and Wang, C},
title = {[Sterilization Effect of an Atmospheric Low Temperature Plasma Jet on Candida albicans Biofilm].},
journal = {Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition},
volume = {50},
number = {3},
pages = {339-343},
pmid = {31631600},
issn = {1672-173X},
abstract = {Objective: To evaluate the sterilization effect of new designed atmospheric low temperature plasma jet on Candida albicans (C. albicans) biofilm.<br><br>Methods: C. albicans was grown into the logarithmic phase, and then was added to polystyrene 24-well microtitre plate. The amount of germs were calculated by viable plate counting to determine the reproducibility of each biofilm well. The germs in biofilm were treated by plasma for different exposure time and then the survived germs were quantified by plate counting, the dead cells were determined by staining the biofilm with propidium iodide (PI), and the ultrastructural changes of the germs in biofilm were observed by transmission electron microscopy (TEM).<br><br>Results: When incubated for 72 h, germs tightly polymerized and classical mature biofilm were formed. This atmospheric low temperature plasma jet could inactivate C. albicans biofilm within a short exposure time. C. albicans were 90% inactivated when treated 20 s and 55 s of plasma treatment reduced bacteria populations to undetectable levels. With the increase of treatment time, enlarged fluorescent positive area appeared, and more bacteria died with the extending of exposure. The TEM scanning results showed that the new plasma jet inactivated C. albicans biofilm mainly via disrupting cell envelopes and then leading the release of cellular components, thus resulting in loss of cell viability.<br><br>Conclusion: Plasma generated from atmospheric low temperature plasma jet could damage the cell structure of C. albicans and efficiently sterilize C. albicans biofilm.},
}
@article {pmid31630921,
year = {2019},
author = {Evangelista, SS and Guimaraes, NR and Garcia, NB and Santos, SGD and Oliveira, AC},
title = {Effectiveness of manual versus automated cleaning on Staphylococcus epidermidis biofilm removal from the surface of surgical instruments.},
journal = {American journal of infection control},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ajic.2019.08.024},
pmid = {31630921},
issn = {1527-3296},
abstract = {BACKGROUND: Biofilm removal is a challenge during surgical instrument processing. We analyzed the time required for Staphylococcus epidermidis to form biofilms on surgical instruments, and how cleaning methods removed them.<br><br>METHODS: Different areas (ratchet, shank, and jaw) of straight crile forceps were contaminated by soaking in Tryptic Soy Broth containing 106 colony forming units (CFU)/mL of S epidermidis for 1, 2, 4, 6, 8, and 12 hours. S epidermidis adhesion and removal, after manual or automated ultrasonic cleaning, was evaluated by microbiological culture and scanning electron microscopy.<br><br>RESULTS: Microbial load increased with time (101-102 CFU/cm2 after 1 hour; 104 CFU/cm2 after 12 hours). Exopolysaccharide was detected after 2 hours and gradually increased thereafter. Bacterial load was reduced by 1-2 log10 after manual cleaning and 1-3 log10 after automated cleaning, but biofilms were not completely eliminated. In general, bacterial load was lower in shank fragments. This difference was significant at 6 hours.<br><br>CONCLUSIONS: Rapid adhesion of S epidermidis and exopolysaccharide formation was observed on surgical instruments. Automated cleaning was more effective than manual cleaning, but neither method removed biofilms completely. The precleaning conditions and the forceps design are critical factors in processing quality.},
}
@article {pmid31630525,
year = {2019},
author = {Cao, Y and Jana, S and Bowen, L and Tan, X and Liu, H and Rostami, N and Brown, J and Jakubovics, NS and Chen, J},
title = {Hierarchical rose-petal surfaces delay the early-stage bacterial biofilm growth.},
journal = {Langmuir : the ACS journal of surfaces and colloids},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.langmuir.9b02367},
pmid = {31630525},
issn = {1520-5827},
abstract = {A variety of natural surfaces exhibit antibacterial properties; as a result significant efforts in the past decade have been dedicated towards fabrication of biomimetic surfaces that can help control biofilm growth. Examples of such surfaces include rose petals, which possess hierarchical structures like the micro-papillae measuring tens of microns and nano-folds that range in the size of 700 ±100 nm. We duplicated the natural structures on rose-petal surfaces via a simple UV-curable nanocasting technique, and tested the efficacy of these artificial surfaces in preventing biofilm growth using clinically relevant bacteria strains. The rose-petal structured surfaces exhibited hydrophobicity (contact angle~130.8º ±4.3º) and high contact angle hysteresis (~91.0° ±4.9°). Water droplets on rose-petal replicas evaporated following the constant contact line mode, indicating the likely coexistence of both Cassie and Wenzel states (Cassie-Baxter impregnating wetting state). Fluorescent microscopy and image analysis revealed the significantly lower attachment of Staphylococcus epidermidis (86.1± 6.2% less) and Pseudomonas aeruginosa (85.9 ±3.2% less) on the rose-petal structured surfaces, compared with flat surfaces over a period of 2 hours. Extensive biofilm matrix was observed in biofilms formed by both species on flat surfaces after prolonged growth (several days), but was less apparent on rose-petal biomimetic surfaces. In addition, the biomass of S. epidermidis (63.2 ±9.4% less) and P. aeruginosa (76.0 ±10.0% less) biofilms were significantly reduced on the rose-petal structured surfaces, in comparison to the flat surfaces. By comparing P. aeruginosa growth on representative unitary nano-pillars, we demonstrated that hierarchical structures are more effective in delaying biofilm growth. The mechanisms are two-fold: 1) the nano-folds across the hemispherical micro-papillae restrict initial attachment of bacterial cells and delay the direct contacts of cells via cell alignment, and 2) the hemispherical micro-papillae arrays isolate bacterial clusters and inhibit the formation of a fibrous network. The hierarchical features on rose petal surfaces may be useful for developing strategies to control biofilm formation in medical and industrial contexts.},
}
@article {pmid31630018,
year = {2019},
author = {Liu, C and Song, D and Zhang, W and He, Q and Huangfu, X and Sun, S and Sun, Z and Cheng, W and Ma, J},
title = {Constructing zwitterionic polymer brush layer to enhance gravity-driven membrane performance by governing biofilm formation.},
journal = {Water research},
volume = {168},
number = {},
pages = {115181},
doi = {10.1016/j.watres.2019.115181},
pmid = {31630018},
issn = {1879-2448},
abstract = {In this study, zwitterionic polymer brushes with controlled architecture were grafted on the surface of gravity-driven membrane (GDM) via surface-initiated reaction to impart antifouling property. A variety of membrane characterization techniques were conducted to demonstrate the successful functionalization of zwitterionic polymers on PVDF hollow fiber membrane. The membrane underwent 90 min of reaction time possessing strong hydrophilicity and high permeability was determined as the optimal modified membrane. Long-term GDM dynamic fouling experiments operated for 30 days using sewage wastewater as feed solution indicated zwitterionic polymer modified membrane exhibit excellent membrane fouling resistance thus enhanced stable flux. Confocal laser scanning microscopy (CLSM) imaging implied that zwitterionic polymer modification significantly inhibit the adsorption of extracellular polymeric substances (EPS) which dominates fouling propensity, resulting in the formation of a thin biofilm with high porosity under synthetic functions of foulants deposition and microbial activities. Interfacial free energy prediction affirmed the presence of zwitterionic functional layer on membrane surface could substantially decrease the interactions (e.g., electrostatic attractions and hydrophobic effects) between membrane and foulants, thereby reduced flux decline and high stable flux. Our study suggests surface hydrophilic functionalization shows promising potential for improving the performance of ultra-low pressure filtration.},
}
@article {pmid31630005,
year = {2019},
author = {Sebelemetja, M and Moeno, S and Patel, M},
title = {Anti-acidogenic, anti-biofilm and slow release properties of Dodonaea viscosa var. angustifolia flavone stabilized polymeric nanoparticles.},
journal = {Archives of oral biology},
volume = {109},
number = {},
pages = {104586},
doi = {10.1016/j.archoralbio.2019.104586},
pmid = {31630005},
issn = {1879-1506},
abstract = {OBJECTIVE: Dental caries is caused by plaque associated oral bacteria including a pioneer species Streptococcus mutans. It has ability to form biofilm and produce acids in the oral cavity. Many oral hygiene products containing plant derived compounds have been investigated for their anti-S. mutans activity. Dodonaea viscosa var. angustifolia (DVA), has been found to have this property. However, beneficial concentrations are difficult to maintain in the oral cavity due to continual saliva flow which can be overcome using nanotechnology. The aim of this study was to investigate the anti-acidogenic, anti-biofilm and slow release properties of DVA derived flavone stabilized polymeric nanoparticles.<br><br>METHODS: Crude extract prepared from DVA leaves was fractionated to produce subfractions and the beneficial subfraction (F5.1) was obtained. Polymeric nanoparticles (PLGA-PEG) were prepared, stabilized with the DVA subfraction (F5.1/NPs) and characterized. Anti-S. mutans, anti-acidogenic and antibiofilm properties were determined. The subfraction release profile (substantivity) and cytotoxicity was determined. Results were analyzed using the Wilcoxon sum test (Mann-Whitney).<br><br>RESULTS: F5.1/NPs showed anti-S. mutans property (MIC 1.56 mg/ml). Subinhibitory concentrations of these nanoparticles significantly reduced the acid production in S. mutans (p < 0.01) and also reduced the biofilm formation by 92%. The retention and slow release of the beneficial compound was detected up to 12 h, reaching 0.1 mg/ml concentration at pH 7.4 after 4 h and at pH 5.5 after 5 h. IC50 of F5.1/NPs was 62.5 µg/ml.<br><br>CONCLUSION: the DVA flavone containing nanoparticles showed anticariogenic activity with improved substantivity. Therefore, they have potential for use to control dental caries.},
}
@article {pmid31629797,
year = {2019},
author = {Ohadi, M and Forootanfar, H and Dehghan-Noudeh, G and Eslaminejad, T and Ameri, A and Shakibaie, M and Adeli-Sardou, M},
title = {Antimicrobial, anti-biofilm, and anti-proliferative activities of lipopeptide biosurfactant produced by Acinetobacter junii B6.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103806},
doi = {10.1016/j.micpath.2019.103806},
pmid = {31629797},
issn = {1096-1208},
abstract = {Lipopeptide biosurfactants (LPBs) are amphiphilic compounds produced by microorganisms exhibiting various biological activities. The main aim of the present study was to assess the in vitro antimicrobial, anti-biofilm, and cytotoxic effects of LPB produced by Acinetobacter junii (AjL). We determined AjL minimum inhibitory concentration (MIC) against both Gram-positive and Gram-negative bacteria as well as two fungal strains. Also, the anti-biofilm activity of AjL against the biofilm produced by clinically isolated bacterial strains was investigated. The AjL non-selectively showed activity against both Gram-positive and Gram-negative bacterial strains. The obtained results of the present study exhibited that the AjL in concentrations nearly below critical micelle concentration (CMC) has an effective antibacterial activity. It was found that the MIC values of AjL were lower than standard antifungal and it exhibited nearly 100% inhibition against Candida utilis. The attained results of the biofilm formation revealed that AjL disrupted the biofilm of Proteus mirabilis, Staphylococcus aureus, and Pseudomonas aeruginosa at 1250 μg/ml and 2500 μg/ml concentrations. The attained results of cytotoxic effect (determined by WST-1 assay) of the AjL revealed IC50 of 7.8 ± 0.4 mg/ml, 2.4 ± 0.5 mg/ml, and 5.7 ± 0.1 mg/ml, against U87, KB, and HUVEC cell lines, respectively. The results indicated that AjL has a potential application in the relatively new field of biomedicine.},
}
@article {pmid31628906,
year = {2019},
author = {Ghasemi, M and Jenkins, B and Doxey, AC and Sivaloganathan, S},
title = {A study of Nitric Oxide dynamics in a growing biofilm using a density dependent reaction-diffusion model.},
journal = {Journal of theoretical biology},
volume = {},
number = {},
pages = {110053},
doi = {10.1016/j.jtbi.2019.110053},
pmid = {31628906},
issn = {1095-8541},
abstract = {One of a number of critical roles played by NO• as a chemical weapon (generated by the immune system) is to neutralize pathogens. However, the virulence of pathogens depends on the production activity of reductants to detoxify NO•. Broad reactivity of NO• makes it complicated to predict the fate of NO• inside bacteria and its effects on the treatment of any infection. Here, we present a mathematical model of biofilm response to NO•, as a stressor. The model is comprised of a PDE system of highly nonlinear reaction-diffusion equations that we study in computer simulations to determine the positive and negative effects of key parameters on bacterial defenses against NO•. From the reported results, we conjecture that the oscillatory behavior of NO• under a microaerobic regime is a temporal phenomenon and does not give rise to a spatial pattern. It is also shown computationally that decreasing the initial size of the biofilm colony negatively impacts the functionality of reducing agents that deactivate NO•. Whereas nutrient deprivation results in the development of biofilms with heterogeneous structure, its effect on the activity of NO• reductants depends on the oxygen availability, biofilm size, and the amount of NO•.},
}
@article {pmid31628147,
year = {2019},
author = {Scarascia, G and Lehmann, R and Machuca, LL and Morris, C and Cheng, KY and Kaksonen, A and Hong, PY},
title = {Quorum sensing effect on the ability of Desulfovibrio vulgaris to form biofilm and to biocorrode carbon steel in saline conditions.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.01664-19},
pmid = {31628147},
issn = {1098-5336},
abstract = {Sulfate reducing bacteria (SRB) are key contributors to microbial induced corrosion (MIC), which can lead to serious economic and environmental impact. The presence of a biofilm significantly increases the MIC rate. Inhibition of the quorum sensing (QS) system is a promising alternative approach to prevent biofilm formation in various industrial settings, especially considering the significant ecological impact of conventional chemical-based mitigation strategies. In this study, the effect of the QS stimulation and inhibition on Desulfovibrio vulgaris was described in terms of anaerobic respiration, cell activity, biofilm formation and biocorrosion of carbon steel. All these traits were repressed when bacteria were in contact with QS inhibitors, while they were enhanced upon exposure to QS signal molecules as compared to the control. The difference in the treatments was confirmed by transcriptomic analysis performed at different time points after treatments application. Genes related to lactate and pyruvate metabolism, sulfate reduction, electrons transfer and biofilm formation were downregulated upon QS inhibition. On the contrary, QS stimulation led to an upregulation of the above-mentioned genes compared with the control. In summary, these results reveal the impact of QS on the activity of D. vulgaris, paving the way towards the prevention of corrosive SRB biofilm formation via QS inhibition.IMPORTANCE Sulfate reducing bacteria (SRB) are considered key contributors to biocorrosion, particularly in saline environments. Biocorrosion imposes tremendous economic costs, and common approaches to mitigate this problem involve the use of toxic and hazardous chemicals (e.g. chlorine), which raise health and environmental safety concerns. Quorum sensing inhibitors (QSI) can be used as an alternative approach to inhibit biofilm formation and biocorrosion. However, this approach would only be effective if SRB rely on QS for the pathways associated with biocorrosion. These pathways would include biofilm formation, electron transfer, and metabolism. This study demonstrates the role of QS in Desulfovibrio vulgaris on the abovementioned pathways through both phenotypic measurements and transcriptomic approach. The results of this study suggest that QSI can be used to mitigate SRB-induced corrosion problems in ecologically sensitive areas.},
}
@article {pmid31627387,
year = {2019},
author = {Shetty, D and Abrahante, JE and Chekabab, SM and Wu, X and Korber, DR and Vidovic, S},
title = {Role of CpxR in Biofilm Development: Expression of Key Fimbrial, O-Antigen and Virulence Operons of Salmonella Enteritidis.},
journal = {International journal of molecular sciences},
volume = {20},
number = {20},
pages = {},
doi = {10.3390/ijms20205146},
pmid = {31627387},
issn = {1422-0067},
abstract = {Salmonella Enteritidis is a non-typhoidal serovar of great public health significance worldwide. The RpoE sigma factor and CpxRA two-component system are the major regulators of the extracytoplasmic stress response. In this study, we found that the CpxR has highly significant, but opposite effects on the auto-aggregation and swarming motility of S. Enteritidis. Auto-aggregation was negatively affected in the ∆cpxR mutant, whereas the same mutant significantly out-performed its wild-type counterpart with respect to swarming motility, indicating that the CpxR plays a role in biofilm-associated phenotypes. Indeed, biofilm-related assays showed that the CpxR is of critical importance in biofilm development under both static (microtiter plate) and dynamic (flow cell) media flow conditions. In contrast, the RpoE sigma factor showed no significant role in biofilm development under dynamic conditions. Transcriptomic analysis revealed that the cpxR mutation negatively affected the constitutive expression of the operons critical for biosynthesis of O-antigen and adherence, but positively affected the expression of virulence genes critical for Salmonella-mediated endocytosis. Conversely, CpxR induced the expression of curli csgAB and fimbrial stdAC operons only during biofilm development and flagellar motAB and fliL operons exclusively during the planktonic phase, indicating a responsive biofilm-associated loop of the CpxR regulator.},
}
@article {pmid31626589,
year = {2019},
author = {Mangas, EL and Rubio, A and Álvarez-Marín, R and Labrador-Herrera, G and Pachón, J and Pachón-Ibáñez, ME and Divina, F and Pérez-Pulido, AJ},
title = {Pangenome of Acinetobacter baumannii uncovers two groups of genomes, one of them with genes involved in CRISPR/Cas defence systems associated with the absence of plasmids and exclusive genes for biofilm formation.},
journal = {Microbial genomics},
volume = {},
number = {},
pages = {},
doi = {10.1099/mgen.0.000309},
pmid = {31626589},
issn = {2057-5858},
abstract = {Acinetobacter baumannii is an opportunistic bacterium that causes hospital-acquired infections with a high mortality and morbidity, since there are strains resistant to virtually any kind of antibiotic. The chase to find novel strategies to fight against this microbe can be favoured by knowledge of the complete catalogue of genes of the species, and their relationship with the specific characteristics of different isolates. In this work, we performed a genomics analysis of almost 2500 strains. Two different groups of genomes were found based on the number of shared genes. One of these groups rarely has plasmids, and bears clustered regularly interspaced short palindromic repeat (CRISPR) sequences, in addition to CRISPR-associated genes (cas genes) or restriction-modification system genes. This fact strongly supports the lack of plasmids. Furthermore, the scarce plasmids in this group also bear CRISPR sequences, and specifically contain genes involved in prokaryotic toxin-antitoxin systems that could either act as the still little known CRISPR type IV system or be the precursors of other novel CRISPR/Cas systems. In addition, a limited set of strains present a new cas9-like gene, which may complement the other cas genes in inhibiting the entrance of new plasmids into the bacteria. Finally, this group has exclusive genes involved in biofilm formation, which would connect CRISPR systems to the biogenesis of these bacterial resistance structures.},
}
@article {pmid31625519,
year = {2019},
author = {Behzadpour, N and Akbari, N and Sattarahmady, N},
title = {Photothermal inactivation of methicillin-resistant Staphylococcus aureus: anti-biofilm mediated by a polypyrrole-carbon nanocomposite.},
journal = {IET nanobiotechnology},
volume = {13},
number = {8},
pages = {800-807},
doi = {10.1049/iet-nbt.2018.5340},
pmid = {31625519},
issn = {1751-875X},
abstract = {Widespread resistance to antibiotics amongst pathogens has become a tremendous challenge of high morbidity and mortality rates which increases the needs to exploring novel methods of treatment. An efficient antimicrobial procedure to root out pathogenic bacteria is photothermal therapy. In this study, antimicrobial effects of a polypyrrole-carbon nanocomposite (PPy-C) upon laser irradiation in order to destroy the pathogenic gram-positive bacterium, methicillin-resistant Staphylococcus aureus (MRSA) were assessed. The bacterial cells were incubated with 500, 750 and 1000 μg ml-1 concentrations of PPy-C and irradiated with an 808-nm laser at a power density of 1.0 W cm-2. To indicate the biocompatibility and toxic effect of the nanocomposite without and with laser irradiation, the authors counted the number of CFUs and compared it to an untreated sample. Antibacterial mechanisms of PPy-C were assessed through temperature increment, reactive oxygen species production, and protein and DNA leakages. Photothermal heating assay showed that 26°C temperature increases in the presence of 1000 µg ml-1 PPy-C led to >98% killing of MRSA. Furthermore, 20 min radiation of near-infrared light to PPy-C in different concentrations indicated destruction and reduction in the MRSA biofilm formation. Therefore, PPy-C was introduced as a photothermal absorber with a bactericidal effect in MRSA.},
}
@article {pmid31625441,
year = {2019},
author = {Bombarda, GF and Rosalen, PL and Paganini, ER and Garcia, MA and Silva, DR and Lazarini, JG and Freires, IA and Regasini, LO and Sardi, JC},
title = {Bioactive molecule optimized for biofilm reduction related to childhood caries.},
journal = {Future microbiology},
volume = {14},
number = {},
pages = {1207-1220},
doi = {10.2217/fmb-2019-0144},
pmid = {31625441},
issn = {1746-0921},
abstract = {Aim: To evaluate antimicrobial activity of a new nitrochalcone (NC-E08) against Candida albicans and Streptococcus mutans, and its toxicity. Materials &amp; methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration/minimum fungicidal concentration (MFC) were determined against C. albicans and S. mutans, as well as antibiofilm potential and toxicity (human gingival fibroblast and Galleria mellonella). Infection and treatment were performed in G. mellonella. Results &amp; conclusion: NC-E08 showed antimicrobial activity in C. albicans (MIC: 0.054 mM) and S. mutans (MIC: 0.013 mM); 10xMIC treatment reduced 4.0 log10 biofilms for both strains and there was a reduction in survival of mixed biofilms of C. albicans and S. mutans (6.0 and 4.0 log10, respectively). NC-E08 showed no cytotoxicity in human gingival fibroblast cells and G. mellonella. NC-E08 after larval infection protected them 90% (p < 0.05). Thus, is a promising one for the prevention and treatment of S. mutans and C. albicans infections.},
}
@article {pmid31623950,
year = {2019},
author = {Robertson, SN and Childs, PG and Akinbobola, A and Henriquez, FL and Ramage, G and Reid, S and Mackay, WG and Williams, C},
title = {Reduction of Pseudomonas aeruginosa biofilm formation through the application of nanoscale vibration.},
journal = {Journal of bioscience and bioengineering},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jbiosc.2019.09.003},
pmid = {31623950},
issn = {1347-4421},
abstract = {Bacterial biofilms pose a significant burden in both healthcare and industrial environments. With the limited effectiveness of current biofilm control strategies, novel or adjunctive methods in biofilm control are being actively pursued. Reported here, is the first evidence of the application of nanovibrational stimulation (nanokicking) to reduce the biofilm formation of Pseudomonas aeruginosa. Nanoscale vertical displacements (approximately 60 nm) were imposed on P. aeruginosa cultures, with a significant reduction in biomass formation observed at frequencies between 200 and 4000 Hz at 24 h. The optimal reduction of biofilm formation was observed at 1 kHz, with changes in the physical morphology of the biofilms. Scanning electron microscope imaging of control and biofilms formed under nanovibrational stimulation gave indication of a reduction in extracellular matrix (ECM). Quantification of the carbohydrate and protein components of the ECM was performed and showed a significant reduction at 24 h at 1 kHz frequency. To model the forces being exerted by nanovibrational stimulation, laser interferometry was performed to measure the amplitudes produced across the Petri dish surfaces. Estimated peak forces on each cell, associated with the nanovibrational stimulation technique, were calculated to be in the order of 10 pN during initial biofilm formation. This represents a potential method of controlling microbial biofilm formation in a number of important settings in industry and medical related processes.},
}
@article {pmid31622708,
year = {2019},
author = {Choi, M and Hasan, N and Cao, J and Lee, J and Phyu Hlaing, S and Yoo, JW},
title = {Chitosan-based nitric oxide-releasing dressing for anti-biofilm and in vivo healing activities in MRSA biofilm-infected wounds.},
journal = {International journal of biological macromolecules},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijbiomac.2019.10.009},
pmid = {31622708},
issn = {1879-0003},
abstract = {Bacterial biofilms on wounds impair the healing process and often lead to chronic wounds. Chitosan is a well-known biopolymer with antimicrobial and anti-biofilm effects. S-nitrosoglutathione (GSNO) has been identified as a promising nitric oxide (NO) donor to defend against pathogenic biofilms and enhance wound healing activities. In this study, we prepared NO-releasing chitosan film (CS/NO film) and evaluated its anti-biofilm activity and in vivo wound healing efficacy against methicillin-resistant Staphylococcus aureus (MRSA) biofilm-infected wounds in diabetic mice. The in vitro release study showed sustained release of NO over 3 days in simulated wound fluid. The CS/NO film significantly enhanced antibacterial activity against MRSA by >3 logs reduction in bacterial viability. Moreover, CS/NO film exhibited a 3-fold higher anti-biofilm activity than the control and CS film. In in vivo MRSA biofilm-infected wounds, the CS/NO film-treated group showed faster biofilm dispersal, wound size reduction, epithelialization rates, and collagen deposition than the untreated and CS film-treated groups. Therefore, the CS/NO film investigated in this study could be a promising approach for the treatment of MRSA biofilm-infected wounds.},
}
@article {pmid31622331,
year = {2019},
author = {Kobayashi, K and Ikemoto, Y},
title = {Biofilm-associated toxin and extracellular protease cooperatively suppress competitors in Bacillus subtilis biofilms.},
journal = {PLoS genetics},
volume = {15},
number = {10},
pages = {e1008232},
doi = {10.1371/journal.pgen.1008232},
pmid = {31622331},
issn = {1553-7404},
abstract = {In nature, most bacteria live in biofilms where they compete with their siblings and other species for space and nutrients. Some bacteria produce antibiotics in biofilms; however, since the diffusion of antibiotics is generally hindered in biofilms by extracellular polymeric substances, i.e., the biofilm matrix, their function remains unclear. The Bacillus subtilis yitPOM operon is a paralog of the sdpABC operon, which produces the secreted peptide toxin SDP. Unlike sdpABC, yitPOM is induced in biofilms by the DegS-DegU two-component regulatory system. High yitPOM expression leads to the production of a secreted toxin called YIT. Expression of yitQ, which lies upstream of yitPOM, confers resistance to the YIT toxin, suggesting that YitQ is an anti-toxin protein for the YIT toxin. The alternative sigma factor SigW also contributes to YIT toxin resistance. In a mutant lacking yitQ and sigW, the YIT toxin specifically inhibits biofilm formation, and the extracellular neutral protease NprB is required for this inhibition. The requirement for NprB is eliminated by Δeps and ΔbslA mutations, either of which impairs production of biofilm matrix polymers. Overexpression of biofilm matrix polymers prevents the action of the SDP toxin but not the YIT toxin. These results indicate that, unlike the SDP toxin and many conventional antibiotics, the YIT toxin can pass through layers of biofilm matrix polymers to attack cells within biofilms with assistance from NprB. When the wild-type strain and the YIT-sensitive mutant were grown together on a solid medium, the wild-type strain formed biofilms that excluded the YIT-sensitive mutant. This observation suggests that the YIT toxin protects B. subtilis biofilms against competitors. Several bacteria are known to produce antibiotics in biofilms. We propose that some bacteria including B. subtilis may have evolved specialized antibiotics that can function within biofilms.},
}
@article {pmid31621697,
year = {2019},
author = {He, Y and Wan, X and Xiao, K and Lin, W and Li, J and Li, Z and Luo, F and Tan, H and Li, J and Fu, Q},
title = {Anti-biofilm surfaces from mixed dopamine-modified polymer brushes: synergistic role of cationic and zwitterionic chains to resist staphyloccocus aureus.},
journal = {Biomaterials science},
volume = {},
number = {},
pages = {},
doi = {10.1039/c9bm01275c},
pmid = {31621697},
issn = {2047-4849},
abstract = {Infections resulting from the attachment of bacteria and biofilm formation on the surface of medical implants give rise to a severe problem for medical device safety. Thus, the development of antibacterial materials that integrate bactericidal and antifouling properties is a promising approach to prevent biomaterial-associated infections. In this study, two types of dopamine-modified polymers, dopamine-terminated quaternary ammonium salt polymer (D-PQAs) with various lengths of N-alkyl chain (D-PQA4C, D-PQA8C, and D-PQA12C) and dopamine-terminated poly(sulfobetaine methacrylate) (D-PSBMA), were synthesized via atom transfer radical polymerization (ATRP). Mixed polymer brushes of D-PQAs and D-PSBMA with various ratios were well-integrated onto the surface of a silicon wafer via a facile mussel-inspired adhesion. We demonstrate that the synergistic antibacterial effect depends on both the ratio of the two components and the surface structures of the mixed polymer brushes, originating from the interactions between D-PQAs and D-PSBMA. The N-alkyl chain length of D-PQAs influenced the distribution and orientation of the alkyl chain on the mixed polymer brushes. A chart of the antibacterial efficiency of the mixed polymer brushes was obtained to reveal the synergistic role of their cationic and zwitterionic chains to resist S. aureus. The dominant amount of antifouling D-PSBMA with a minor amount of bactericidal D-PQAs with a short N-alkyl chain length facilitated the synergistic antibacterial effect. The selected polymer brushes (PSBMA/PQA4C-10%, PSBMA/PQA4C-30%, and PSBMA/PQA8C-10%) could effectively prevent biofilm formation by S. aureus for a long time, while having good biocompatibility. This work may provide a universal design strategy for the preparation of anti-biofilm and biocompatible surfaces for biomedical applications.},
}
@article {pmid31621183,
year = {2019},
author = {Hu, Y and Liu, X and Teng, AMR and Gu, JD and Cao, B},
title = {Optogenetic modulation of a catalytic biofilm for biotransformation of indole into tryptophan.},
journal = {ChemSusChem},
volume = {},
number = {},
pages = {},
doi = {10.1002/cssc.201902413},
pmid = {31621183},
issn = {1864-564X},
abstract = {In green chemical synthesis, biofilms as biocatalysts have shown great promise. Efficient biofilm-mediated biocatalysis requires the modulation of biofilm formation. Optogenetic tools are ideal for controlling biofilms, as light is non-invasive, easily controllable and cost-efficient. In this study, we employed a near infrared (NIR) light-responsive gene circuit to modulate the cellular level of c-di-GMP, a central regulator of the prokaryote biofilm lifestyle, which allows us to regulate biofilm formation using NIR light. By applying the engineered biofilm to catalyze the biotransformation of indole into tryptophan in submerged biofilm reactors, we showed that NIR light enhanced biofilm formation to result in ~ 30% increase in tryptophan yield, which demonstrates the feasibility of applying light to modulate the formation and performance of catalytic biofilms for chemical production. The c-di-GMP targeted optogenetic approach for modulating catalytic biofilm we have demonstrated here would allow the wide application for further biofilm-mediated biocatalysis.},
}
@article {pmid31621139,
year = {2019},
author = {Gowri, M and Jayashree, B and Jeyakanthan, J and Girija, EK},
title = {Sertraline as a Promising Antifungal Agent: Inhibition of Growth and Biofilm of Candida auris With Special Focus on the Mechanism of Action In vitro.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14490},
pmid = {31621139},
issn = {1365-2672},
abstract = {AIM: The aim of this present study was to investigate the antifungal mechanism of sertraline against Candida auris (C. auris) and its effect on biofilm formation.<br><br>METHODS AND RESULTS: Sertraline, a repurposing drug with a history of human use for the treatment of depression was screened against three different isolates of C. auris, and found efficient antifungal activity. The antifungal activity of sertraline was further confirmed by killing kinetics assay and post-antifungal effect. Sertraline inhibited C. auris yeast to hyphae conversion and further the inhibition of biofilm formation showed 68% inhibition upon treatment. Cell damage caused to C. auris after treatment with sertraline was observed using SEM and cell membrane damage was ascertained using flow cytometry by Propidium Iodide (PI) uptake assay. The results of sorbitol protection assay and ergosterol effect assay suggested that sertraline did not affect the cell wall and did not act by binding to membrane ergosterol. The mechanism of action of sertraline against C. auris was understood through in silico docking studies that revealed sertraline binding nature to sterol 14 alpha demethylase which is involved in ergosterol biosynthesis. Ergosterol that was quantified from treated cells showed a 5.5-fold decrease in ergosterol production.<br><br>CONCLUSION: Sertraline displayed promising antifungal activity against C. auris involved in candidiasis infection and the mechanism of action was predicted.<br><br>The results of this study can encourage for the development of new antifungal agents and can be promising against C. auris infection.},
}
@article {pmid31621078,
year = {2019},
author = {Wolf, DI and Vis, ML},
title = {Stream algal biofilm community diversity along an acid mine drainage recovery gradient using multi-marker metabarcoding.},
journal = {Journal of phycology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jpy.12935},
pmid = {31621078},
issn = {1529-8817},
abstract = {In southeastern Ohio, active remediation of streams affected by Acid Mine Drainage (AMD) has proven to be successful for some streams, while others have not recovered based on macroinvertebrate assessment. In this study, biofilms were collected from three Moderately Impaired, three Recovered, and two Unimpaired streams. The biodiversity was characterized by metabarcoding using two universal barcode markers (16S and 18S) along with two algal specific markers (UPA and rbcL) and high-throughput amplicon sequencing. For each marker, the ordination of Bray-Curtis Index calculated from the total Amplicon Sequence Variants (ASVs) present in each stream showed the Unimpaired and Recovered streams clustered, while Moderately Impaired streams were more distant. Focusing on the algal ASVs, the Shannon index for the rbcL and UPA markers showed significantly lower alpha diversity in Moderately Impaired streams compared to Unimpaired streams, but the Recovered streams were not significantly different from the other two stream categories. The two universal markers together captured all algal phyla providing an outline of the diversity, but the two algal specific markers produced a greater number of ASVs and taxonomic depth for algal taxa. Further examination of the UPA marker revealed a drastic decrease in relative abundance of diatoms in Moderately Impaired streams compared to Recovered and Unimpaired streams. Likewise, diatom genera identified in the rbcL data and indicative of stream water quality showed marked differences in relative abundance among stream categories. Although all markers were useful, the algal specific UPA and rbcL contributed more insights into algal community differences among stream categories.},
}
@article {pmid31618938,
year = {2019},
author = {Zapién-Chavarría, KA and Plascencia-Terrazas, A and Venegas-Ortega, MG and Varillas-Torres, M and Rivera-Chavira, BE and Adame-Gallegos, JR and González-Rangel, MO and Nevárez-Moorillón, GV},
title = {Susceptibility of Multidrug-Resistant and Biofilm-Forming Uropathogens to Mexican Oregano Essential Oil.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/antibiotics8040186},
pmid = {31618938},
issn = {2079-6382},
support = {Fellowship No. 584251 for M.G.V.O.//Consejo Nacional de Ciencia y Tecnología/ ; Fellowship No. 597284 for M.V.T.//Consejo Nacional de Ciencia y Tecnología/ ; },
abstract = {Antibiotic resistance along with biofilm formation increases the difficulty for antibiotic therapy in urinary tract infections. Bioactive molecules derived from plants, such as those present in essential oils, can be used to treat bacterial infections. Oregano is one of the spices to have antimicrobial activity. Therefore, three Mexican oregano essential oils (two Lippia berlandieri Schauer and one Poliomintha longiflora) were tested for antimicrobial capacity against multidrug-resistant, biofilm-forming bacterial isolates. Clinical isolates from urinary tract infections were tested for antibiotic resistance. Multidrug-resistant isolates were evaluated for biofilm formation, and Mexican oregano antimicrobial effect was determined by the minimal inhibitory (CMI) and minimal bactericidal concentrations (CMB). The selected isolates were identified by molecular phylogenetic analysis. Sixty-one isolates were included in the study; twenty were characterized as multidrug-resistant and from those, six were strong biofilm formers. Three isolates were identified as Escherichia coli, two as Pseudomonas aeruginosa and one as Enterococcus faecalis based on the phylogenetic analysis of 16 S rRNA gene sequences. The antimicrobial effect was bactericidal; E. faecalis was the most susceptible (<200 mg/L CMI/CMB), and P. aeruginosa was the most resistant (>2,000 mg/L CMI/CMB). There was a range of 500-1000 mg/L (CMI/CMB) for the E. coli isolates. Mexican oregano essential oils demonstrated antimicrobial efficacy against multidrug-resistant clinical isolates.},
}
@article {pmid31618903,
year = {2019},
author = {Pandey, VK and Srivastava, KR and Ajmal, G and Thakur, VK and Gupta, VK and Upadhyay, SN and Mishra, PK},
title = {Differential Susceptibility of Catheter Biomaterials to Biofilm-Associated Infections and Their Remedy by Drug-Encapsulated Eudragit RL100 Nanoparticles.},
journal = {International journal of molecular sciences},
volume = {20},
number = {20},
pages = {},
doi = {10.3390/ijms20205110},
pmid = {31618903},
issn = {1422-0067},
abstract = {Biofilms are the cause of major bacteriological infections in patients. The complex architecture of Escherichia coli (E. coli) biofilm attached to the surface of catheters has been studied and found to depend on the biomaterial's surface properties. The SEM micrographs and water contact angle analysis have revealed that the nature of the surface affects the growth and extent of E. coli biofilm formation. In vitro studies have revealed that the Gram-negative E. coli adherence to implanted biomaterials takes place in accordance with hydrophobicity, i.e., latex > silicone > polyurethane > stainless steel. Permanent removal of E. coli biofilm requires 50 to 200 times more gentamicin sulfate (G-S) than the minimum inhibitory concentration (MIC) to remove 90% of E. coli biofilm (MBIC90). Here, in vitro eradication of biofilm-associated infection on biomaterials has been done by Eudragit RL100 encapsulated gentamicin sulfate (E-G-S) nanoparticle of range 140 nm. It is 10-20 times more effective against E. coli biofilm-associated infections eradication than normal unentrapped G-S. Thus, Eudragit RL100 mediated drug delivery system provides a promising way to reduce the cost of treatment with a higher drug therapeutic index.},
}
@article {pmid31617725,
year = {2019},
author = {Altube, MJ and Martinez, MM and Malheiros, B and Maffia, PC and Barbosa, LRS and Morilla, MJ and Romero, EL},
title = {Fast biofilm penetration and anti-PAO1 activity of nebulized azythromicin in nanoarchaeosomes.},
journal = {Molecular pharmaceutics},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.molpharmaceut.9b00721},
pmid = {31617725},
issn = {1543-8392},
abstract = {Azithromycin (AZ) is a broad-spectrum antibiotic with anti-inflammatory and anti-quorum sensing activity against biofilm forming bacteria such as Pseudomonas aeruginosa (Pa). AZ administered by oral or parenteral routes however, neither efficiently access nor remain in therapeutic doses inside pulmonary biofilm depths. Instead, inhaled nanocarriers loaded with AZ may revert the problem of low accessibility and permanence of AZ into biofilms, enhancing its antimicrobial activity. The first inhalable nanovesicle formulation of AZ: nanoarchaeosome-AZ (nanoARC-AZ) is here presented. NanoARC prepared with total polar archaeolipids (TPA, rich in 2,3-di-O-phytanyl-sn-glycero-1-phospho-(3'-sn-glycerol-1'-methylphosphate) (PGP-Me) from Halorubrum tebenquichense archaebacteria, consisted of ∽ 180 nm diameter nanovesicles, loaded with 0.28 w:w AZ:TPA. NanoARC-AZ displayed lower MIC and MBC, higher preformed biofilm disruptive and anti-PAO1 activity in biofilm than AZ. NanoARC penetrated and disrupted the structure of PAO1 biofilm within only 1 h. 2 mL of 15 μg/mL AZ nanoARC-AZ nebulized along 5 min rendered AZ doses compatible with in vitro antibacterial activity. The strong association between AZ and nanoARC bilayer, combined electrostatic attraction and trapping into perpendicular methyl groups of archaeolipids, as determined by Laurdan fluorescence anisotropy, generalized polarization and SAXS, was critical to stabilize during storage and endure shear forces of nebulization. NanoARC-AZ was non-cytotoxic on A549 cells and human THP-1 derived macrophages, deserving further preclinical exploration as enhancers of AZ anti-PAO1 activity.},
}
@article {pmid31616604,
year = {2019},
author = {Chinnici, J and Yerke, L and Tsou, C and Busarajan, S and Mancuso, R and Sadhak, ND and Kim, J and Maddi, A},
title = {Candida albicans cell wall integrity transcription factors regulate polymicrobial biofilm formation with Streptococcus gordonii.},
journal = {PeerJ},
volume = {7},
number = {},
pages = {e7870},
doi = {10.7717/peerj.7870},
pmid = {31616604},
issn = {2167-8359},
abstract = {Polymicrobial biofilms play important roles in oral and systemic infections. The oral plaque bacterium Streptococcus gordonii is known to attach to the hyphal cell wall of the fungus Candida albicans to form corn-cob like structures in biofilms. However, the role of C. albicans in formation of polymicrobial biofilms is not completely understood. The objective of this study was to determine the role of C. albicans transcription factors in regulation of polymicrobial biofilms and antibiotic tolerance of S. gordonii. The proteins secreted by C. albicans and S. gordonii in mixed planktonic cultures were determined using mass spectrometry. Antibiotic tolerance of S. gordonii to ampicillin and erythromycin was determined in mixed cultures and mixed biofilms with C. albicans. Additionally, biofilm formation of S. gordonii with C. albicans knock-out mutants of 45 transcription factors that affect cell wall integrity, filamentous growth and biofilm formation was determined. Furthermore, these mutants were also screened for antibiotic tolerance in mixed biofilms with S. gordonii. Analysis of secreted proteomes resulted in the identification of proteins being secreted exclusively in mixed cultures. Antibiotic testing showed that S. gordonii had significantly increased survival in mixed planktonic cultures with antibiotics as compared to single cultures. C. albicans mutants of transcription factors Sfl2, Brg1, Leu3, Cas5, Cta4, Tec1, Tup1, Rim101 and Efg1 were significantly affected in mixed biofilm formation. Also mixed biofilms of S. gordonii with mutants of C. albicans transcription factors, Tec1 and Sfl2, had significantly reduced antibiotic tolerance as compared to control cultures. Our data indicates that C. albicans may have an important role in mixed biofilm formation as well as antibiotic tolerance of S. gordonii in polymicrobial biofilms. C. albicans may play a facilitating role than being just an innocent bystander in oral biofilms and infections.},
}
@article {pmid31611856,
year = {2019},
author = {Peng, P and Baldry, M and Gless, BH and Bojer, MS and Espinosa-Gongora, C and Baig, SJ and Andersen, PS and Olsen, CA and Ingmer, H},
title = {Effect of Co-inhabiting Coagulase Negative Staphylococci on S. aureus agr Quorum Sensing, Host Factor Binding, and Biofilm Formation.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2212},
doi = {10.3389/fmicb.2019.02212},
pmid = {31611856},
issn = {1664-302X},
abstract = {Staphylococcus aureus is a commensal colonizer of both humans and animals, but also an opportunistic pathogen responsible for a multitude of diseases. In recent years, colonization of pigs by methicillin resistant S. aureus has become a problem with increasing numbers of humans being infected by livestock strains. In S. aureus colonization and virulence factor expression is controlled by the agr quorum sensing system, which responds to and is activated by self-generated, autoinducing peptides (AIPs). AIPs are also produced by coagulase negative staphylococci (CoNS) commonly found as commensals in both humans and animals, and interestingly, some of these inhibit S. aureus agr activity. Here, we have addressed if cross-communication occurs between S. aureus and CoNS strains isolated from pig nares, and if so, how properties such as host factor binding and biofilm formation are affected. From 25 pig nasal swabs we obtained 54 staphylococcal CoNS isolates belonging to 8 different species. Of these, none were able to induce S. aureus agr as monitored by reporter gene fusions to agr regulated genes but a number of agr-inhibiting species were identified including Staphylococcus hyicus, Staphylococcus simulans, Staphylococcus arlettae, Staphylococcus lentus, and Staphylococcus chromogenes. After establishing that the inhibitory activity was mediated via AgrC, the receptor of AIPs, we synthesized selective AIPs to explore their effect on adhesion of S. aureus to fibronectin, a host factor involved in S. aureus colonization. Here, we found that the CoNS AIPs did not affect adhesion of S. aureus except for strain 8325-4. When individual CoNS strains were co-cultured together with S. aureus we observed variable degrees of biofilm formation which did not correlate with agr interactions. Our results show that multiple CoNS species can be isolated from pig nares and that the majority of these produce AIPs that inhibit S. aureus agr. Further they show that the consequences of the interactions between CoNS and S. aureus are complex and highly strain dependent.},
}
@article {pmid31611714,
year = {2019},
author = {Tam, A and Green, JEF and Balasuriya, S and Tek, EL and Gardner, JM and Sundstrom, JF and Jiranek, V and Binder, BJ},
title = {A thin-film extensional flow model for biofilm expansion by sliding motility.},
journal = {Proceedings. Mathematical, physical, and engineering sciences},
volume = {475},
number = {2229},
pages = {20190175},
doi = {10.1098/rspa.2019.0175},
pmid = {31611714},
issn = {1364-5021},
abstract = {In the presence of glycoproteins, bacterial and yeast biofilms are hypothesized to expand by sliding motility. This involves a sheet of cells spreading as a unit, facilitated by cell proliferation and weak adhesion to the substratum. In this paper, we derive an extensional flow model for biofilm expansion by sliding motility to test this hypothesis. We model the biofilm as a two-phase (living cells and an extracellular matrix) viscous fluid mixture, and model nutrient depletion and uptake from the substratum. Applying the thin-film approximation simplifies the model, and reduces it to one-dimensional axisymmetric form. Comparison with Saccharomyces cerevisiae mat formation experiments reveals good agreement between experimental expansion speed and numerical solutions to the model with O (1) parameters estimated from experiments. This confirms that sliding motility is a possible mechanism for yeast biofilm expansion. Having established the biological relevance of the model, we then demonstrate how the model parameters affect expansion speed, enabling us to predict biofilm expansion for different experimental conditions. Finally, we show that our model can explain the ridge formation observed in some biofilms. This is especially true if surface tension is low, as hypothesized for sliding motility.},
}
@article {pmid31610517,
year = {2019},
author = {Beni, AA and Esmaeili, A},
title = {Design and optimization of a new reactor based on biofilm-ceramic for industrial wastewater treatment.},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {255},
number = {Pt 2},
pages = {113298},
doi = {10.1016/j.envpol.2019.113298},
pmid = {31610517},
issn = {1873-6424},
abstract = {A biofilm reactor was designed with flat ceramic substrates to remove Co(II), Ni(II) and Zn(II) from industrial wastewater. The ceramics were made of clay and nano-rubber with high mechanical resistance. The surface of the ceramic substrate was modified with neutral fiber and nano-hydroxyapatite. A uniform and stable biofilm mass of 320 g with 2 mm of thickness was produced on the modified ceramic after 3 d. The micro-organisms were identified in the biofilm by polymerase chain reaction (PCR) method. Functional groups of biofilms were identified with a Fourier transform infrared spectrometer (FT-IR). Experiments were designed by central composite design (CCD) using the responsive surface method (RSM). The biosorption process was optimized at pH = 5.8, temperature = 22 °C, feed flux of heavy metal wastewater = 225 ml, substrate flow = 30 ml, and retention time = 7.825 h. The kinetic data was analyzed by pseudo first-order and pseudo second-order kinetic models. Isotherm models and thermodynamic parameters were applied to describe the biosorption equilibrium data of the metal ions on the biofilm-ceramic. The maximum biosorption efficiency and capacity of heavy metal ions were about 72% and 57.21 mg, respectively.},
}
@article {pmid31609795,
year = {2019},
author = {Pai, AB and McGuire, MD and Davidge, KN and Dean, MC and Costello, GN and Souza, E and Mukherjee, S and Heung, M and Yevzlin, AS and Yessayan, LT},
title = {Lipoteichoic acid as a Potential Noninvasive Marker of Biofilm in Dialysis Access.},
journal = {ASAIO journal (American Society for Artificial Internal Organs : 1992)},
volume = {},
number = {},
pages = {},
doi = {10.1097/MAT.0000000000001091},
pmid = {31609795},
issn = {1538-943X},
abstract = {Tunneled central venous catheters (TCVCs) are colonized by Gram-positive organisms and form biofilm. Lipoteichoic acid (LTA) is a Gram-positive cell wall component that can be measured in serum. The purpose of this pilot study was to characterize LTA concentrations in hemodialysis (HD) patients with TCVCs compared to other access types and to evaluate biofilm morphology and microbiology in TCVCs removed by clinical decision. The study enrolled patients with TCVCs (18), grafts (19), and fistulas (18). Blood samples were collected before HD, at 30 minutes, 2 hours, and end of HD. Catheters removed by clinical decision were evaluated by scanning electron microscopy (SEM) for biofilm morphology, and portions of the catheter were cultured. LTA was detectable in all samples and concentrations increased significantly in all access types during HD (p < 0.05 for all comparisons). Patients with TCVCs that had a >30% increase in LTA concentration from baseline also had the greatest rate of increase (slope) compared to grafts and fistulas (p = 0.03 and p = 0.04, respectively). Catheters removed by clinical decision (n = 7) and examined by SEM had deposition of fibrin. Cultures revealed polymicrobial colonization. TCVCs had the highest rate of increase of LTA during HD. Further studies to determine the source of LTA in patients with AVG and AVF are warranted.},
}
@article {pmid31608256,
year = {2019},
author = {Jwa, SK},
title = {Efficacy of Moringa oleifera Leaf Extracts against Cariogenic Biofilm.},
journal = {Preventive nutrition and food science},
volume = {24},
number = {3},
pages = {308-312},
doi = {10.3746/pnf.2019.24.3.308},
pmid = {31608256},
issn = {2287-1098},
abstract = {Moringa oleifera leaves are beneficial for human health. Dental caries is closely related with cariogenic biofilm, which is an oral biofilm containing a high proportion of Streptococcus mutans. The purpose of this study was to investigate the antimicrobial effects of the M. oleifera leaf extracts on S. mutans and formation of cariogenic biofilm. Extract from M. oleifera leaves was derived using distilled water (DW) and ethyl alcohol (EtOH). S. mutans susceptibility assays were performed for each extract. Cariogenic biofilm was formed with or without DW and EtOH extract, and cariogenic biofilm was treated with both extracts. The biofilm was observed by confocal laser microscopy, and the bacteria in the biofilm were counted. Both extracts showed antimicrobial activity against S. mutans and inhibited formation of cariogenic biofilm. The EtOH extracts exhibited anti-biofilm activity. M. oleifera leaves may be potential candidates to prevent dental caries.},
}
@article {pmid31608016,
year = {2019},
author = {Catão, ECP and Pollet, T and Misson, B and Garnier, C and Ghiglione, JF and Barry-Martinet, R and Maintenay, M and Bressy, C and Briand, JF},
title = {Shear Stress as a Major Driver of Marine Biofilm Communities in the NW Mediterranean Sea.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1768},
doi = {10.3389/fmicb.2019.01768},
pmid = {31608016},
issn = {1664-302X},
abstract = {While marine biofilms depend on environmental conditions and substrate, little is known about the influence of hydrodynamic forces. We tested different immersion modes (dynamic, cyclic and static) in Toulon Bay (north-western Mediterranean Sea; NWMS). The static mode was also compared between Toulon and Banyuls Bays. In addition, different artificial surfaces designed to hamper cell attachment (self-polishing coating: SPC; and fouling-release coating: FRC) were compared to inert plastic. Prokaryotic community composition was affected by immersion mode, surface characteristics and site. Rhodobacteriaceae and Flavobacteriaceae dominated the biofilm community structure, with distinct genera according to surface type or immersion mode. Cell density increased with time, greatly limited by hydrodynamic forces, and supposed to delay biofilm maturation. After 1 year, a significant impact of shear stress on the taxonomic structure of the prokaryotic community developed on each surface type was observed. When surfaces contained no biocides, roughness and wettability shaped prokaryotic community structure, which was not enhanced by shear stress. Conversely, the biocidal effect of SPC surfaces, already major in static immersion mode, was amplified by the 15 knots speed. The biofilm community on SPC was 60% dissimilar to the biofilm on the other surfaces and was distinctly colonized by Sphingomonadaceae ((Alter)Erythrobacter). At Banyuls, prokaryotic community structures were more similar between the four surfaces tested than at Toulon, due possibly to a masking effect of environmental constraints, especially hydrodynamic, which was greater than in Toulon. Finally, predicted functions such as cell adhesion confirmed some of the hypotheses drawn regarding biofilm formation over the artificial surfaces tested here.},
}
@article {pmid31607570,
year = {2019},
author = {Liao, CH and Chen, CS and Chen, YC and Jiang, NE and Farn, CJ and Shen, YS and Hsu, ML and Chang, CH},
title = {Vancomycin-loaded oxidized hyaluronic acid and adipic acid dihydrazide hydrogel: Bio-compatibility, drug release, antimicrobial activity, and biofilm model.},
journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jmii.2019.08.008},
pmid = {31607570},
issn = {1995-9133},
abstract = {BACKGROUND: Prosthesis infection is a difficult-to-treat situation. Hydrogel is a novel biomaterial, which can be applied by simply spraying or by coating on implants before surgery and can be easily mixed with antibiotics.<br><br>METHODS: In order to evaluate the potential use of antibiotic-loaded hydrogel, we incorporated vancomycin into oxidized hyaluronic acid (HA) and adipic acid dihydrazide and evaluated the drug release and antimicrobial activity against methicillin-resistant Staphylococcus aureus (ATCC 29213).<br><br>RESULTS: The average release percentage of vancomycin on day 3 was about 86%. The antibiotic-loaded gel was biocompatible with mesenchymal stem cell, MC3T3, and L929 cell lines. The in vitro inhibition zones of vancomycin-loaded hydrogel [500X minimal inhibition concentration (MIC), 50X MIC, 10X MIC, and blank hydrogel] were 21, 13, 9, and 5 mm, respectively. In the Ti6Al4V implant biofilm model, 0.01-1% vancomycin-loaded gel exhibited significant anti-biofilm activity, measured by the MTT assay.<br><br>CONCLUSIONS: Vancomycin could be loaded onto oxidized HA and adipic acid dihydrazide, which exhibited excellent drug release and in vitro antimicrobial activity with minimal cell toxicity.},
}
@article {pmid31605761,
year = {2019},
author = {Parai, D and Banerjee, M and Dey, P and Mukherjee, SK},
title = {Reserpine attenuates biofilm formation and virulence of Staphylococcus aureus.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103790},
doi = {10.1016/j.micpath.2019.103790},
pmid = {31605761},
issn = {1096-1208},
abstract = {This study investigated the effects of reserpine, the main bioactive compound of Rauwolfia serpentina, on biofilm formation and biofilm-associated virulence factors production in a Gram-positive pathogen, Staphylococcus aureus. Crystal violet assay, MTT assay, Congo red binding, CLSM studies were performed to assess the antibiofilm activity. Molecular docking was performed to explain the possible mode of action, catheter model was used to evaluate its application potential and the combinatorial study was performed in search of an improved therapeutic formulation. Reserpine affects biofilm formation, EPS production, biofilm cell viability and virulence factor production. It could eradicate 72.7% biofilm at ½ × MIC dose and could also stop the metabolic activity of 50.6% bacterial cells in a biofilm. Staphylococcus aureus biofilm- and virulence-regulatory proteins like AgrA, AtlE, Bap, IcaA, SarA and SasG were found to interact with reserpine which might lead to the attenuation of its pathogenicity. Reserpine along with other commercial antibiotics could generate a hightened antibiofilm response and could also eradicate a good percentage of bacterial biofilm from a urinary catheter model. These findings suggested reserpine as a good alternative entity to generate new improved therapeutic formulations.},
}
@article {pmid31605708,
year = {2019},
author = {Dai, L and Wu, TQ and Xiong, YS and Ni, HB and Ding, Y and Zhang, WC and Chu, SP and Ju, SQ and Yu, J},
title = {Ibuprofen-mediated potential inhibition of biofilm development and quorum sensing in Pseudomonas aeruginosa.},
journal = {Life sciences},
volume = {},
number = {},
pages = {116947},
doi = {10.1016/j.lfs.2019.116947},
pmid = {31605708},
issn = {1879-0631},
abstract = {AIMS: Pseudomonas aeruginosa is one of the leading causes of opportunistic and hospital-acquired infections worldwide, which is frequently linked with clinical treatment difficulties. Ibuprofen, a widely used non-steroidal anti-inflammatory drug, has been previously reported to exert antimicrobial activity with the specific mechanism. We hypothesized that inhibition of P. aeruginosa with ibuprofen is involved in the quorum sensing (QS) systems.<br><br>MAIN METHODS: CFU was utilized to assessed the growth condition of P. aeruginosa. Crystal violent staining and acridine orange staining was used to evaluate the biofilm formation and adherence activity. The detection of QS virulence factors such as pyocyanin, elastase, protease, and rhamnolipids were applied to investigation the anti-QS activity of ibuprofen against P. aeruginosa. The production of 3-oxo-C12-HSL and C4-HSL was confirmed by liquid chromatography/mass spectrometry analysis. qRT-PCR was used to identify the QS-related gene expression. Furthermore, we explored the binding effects between ibuprofen and QS-associated proteins with molecular docking.<br><br>KEY FINDINGS: Ibuprofen inhibits P. aeruginosa biofilm formation and adherence activity. And the inhibitory effects of ibuprofen on C4-HSL levels were concentration-dependent (p < 0.05), while it has no effect on 3-oxo-C12-HSL. Moreover, ibuprofen attenuates the production of virulence factors in P. aeruginosa (p < 0.05). In addition, the genes of QS system were decreased after the ibuprofen treatment (p < 0.05). Of note, ibuprofen was binding with LuxR, LasR, LasI, and RhlR at high binding scores.<br><br>SIGNIFICANCE: The antibiofilm and anti-QS activity of ibuprofen suggest that it can be a candidate drug for the treatment of clinical infections with P. aeruginosa.},
}
@article {pmid31603038,
year = {2019},
author = {Mugge, RL and Lee, JS and Brown, TT and Hamdan, LJ},
title = {Marine biofilm bacterial community response and carbon steel loss following Deepwater Horizon spill contaminant exposure.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-13},
doi = {10.1080/08927014.2019.1673377},
pmid = {31603038},
issn = {1029-2454},
abstract = {Steel marine structures provide foci of biodiversity when they develop into artificial reefs. Development begins with deposition of a biofilm. The effects of contaminants from oil spills on biofilm microbiomes, microbially-induced corrosion (MIC) and metal loss may impact preservation of marine metal structures. A microcosm experiment exposed biofilms on carbon steel disks (CSDs) to crude oil, dispersant, and dispersed oil to address their impacts on bacterial composition and metal loss and pitting. Biofilm diversity increased over time in all exposures. Community composition in dispersant and dispersed oil treatments deviated from the controls for the duration of a 12-week experiment. As biofilms matured, Pseudomonadaceae increased while Rhodobacteraceae decreased in abundance in dispersed oil treatments compared to the controls and dispersant treatments. Greatest mass loss and deepest pitting on CSDs were observed in dispersed oil treatments, suggesting impacts manifest as a consequence of increased MIC potential on carbon steel.},
}
@article {pmid31602310,
year = {2019},
author = {Rupel, K and Zupin, L and Ottaviani, G and Bertani, I and Martinelli, V and Porrelli, D and Vodret, S and Vuerich, R and Passos da Silva, D and Bussani, R and Crovella, S and Parsek, M and Venturi, V and Di Lenarda, R and Biasotto, M and Zacchigna, S},
title = {Blue laser light inhibits biofilm formation in vitro and in vivo by inducing oxidative stress.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {29},
doi = {10.1038/s41522-019-0102-9},
pmid = {31602310},
issn = {2055-5008},
abstract = {Resolution of bacterial infections is often hampered by both resistance to conventional antibiotic therapy and hiding of bacterial cells inside biofilms, warranting the development of innovative therapeutic strategies. Here, we report the efficacy of blue laser light in eradicating Pseudomonas aeruginosa cells, grown in planktonic state, agar plates and mature biofilms, both in vitro and in vivo, with minimal toxicity to mammalian cells and tissues. Results obtained using knock-out mutants point to oxidative stress as a relevant mechanism by which blue laser light exerts its anti-microbial effect. Finally, the therapeutic potential is confirmed in a mouse model of skin wound infection. Collectively, these data set blue laser phototherapy as an innovative approach to inhibit bacterial growth and biofilm formation, and thus as a realistic treatment option for superinfected wounds.},
}
@article {pmid31600988,
year = {2019},
author = {Bardhan, T and Chakraborty, M and Bhattacharjee, B},
title = {Bactericidal Activity of Lactic Acid against Clinical, Carbapenem-Hydrolyzing, Multi-Drug-Resistant Klebsiella pneumoniae Planktonic and Biofilm-Forming Cells.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/antibiotics8040181},
pmid = {31600988},
issn = {2079-6382},
support = {Ramanujan Fellowship; SB/S2/RJN-013/2014//Science and Engineering Research Board/ ; },
abstract = {: Carbapenem resistant Klebsiella pneumoniae has been highlighted to be a critical pathogen by the World Health Organization. The objectives of this study were to assess the efficacy of lactic acid (LA) against planktonic cells and biofilms formed by carbapenem-hydrolyzing K. pneumoniae isolates obtained from the nares of preterm neonates. Time-kill assays with graded percentages of (v/v) LA in water were initially carried out against planktonic cells of a meropenem (MRP)-resistant K. pneumoniae isolate, JNM11.C4. The efficacy parameters such as optimal incubation time and minimum inhibitory concentration were determined by comparing colony-forming unit counts (log(10)CFU). Scanning electron microscopy was used to visualize cell damage. Likewise, JNM11.C4 biofilms were treated with graded series of (v/v) LA. Six carbapenem-hydrolyzing isolates were next used to validate the results. A reduction of 3.6 ± 0.6 log(10) CFU/mL in JNM11.C4 planktonic cells and >3 ± 0.03log(10) CFU/mL in biofilm-forming cells were observed using 0.225% and 2% LA, respectively, after three hours. Similar decreases in viable cell-counts were observed both in the case of planktonic (˃3.6 ± 0.3log(10) CFU/mL) and biofilm-forming cells (3.8 ± 0.3log(10) CFU/mL) across all the six clinical isolates. These results indicate that LA is an effective antimicrobial against planktonic carbapenem-hydrolyzing K. pneumoniae cells and biofilms.},
}
@article {pmid31599377,
year = {2019},
author = {Bakraoui, M and Hazzi, M and Karouach, F and Ouhammou, B and El Bari, H},
title = {Experimental biogas production from recycled pulp and paper wastewater by biofilm technology.},
journal = {Biotechnology letters},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10529-019-02735-w},
pmid = {31599377},
issn = {1573-6776},
support = {413223920433//University Ibn Tofail/ ; },
abstract = {OBJECTIVE: The main objective of this study is the evaluation of RPPW anaerobic digestion feasibility at laboratory scale under Mesophilic condition. The experiment is conducted using a two-stage biofilm digester of 5 L capacity with mobile support material.<br><br>RESULTS: Anaerobic treatment of wastewater from recycled pulp and paper industry in Morocco was tested using a laboratory-scale anaerobic biofilm digester that operated under mesophilic conditions over a 70-day. Chemical oxygen demand (COD) efficiency, volatile and total solid (VS, TS) elimination of the substrate during the process were: 78%, 52% and 48% respectively. The system was stable throughout its operating cycle with an optimum pH (7.24), alkalinity (1750 mg CaCO3/L) and a volatile fatty acid value (760 mg/L). The experimental daily biogas production measured reaches a value of 5 L/day with a composition of 71% methane, 27.6% carbon dioxide, 0.2 oxygen and 7713 ppm of the H2S. The study results show that the anaerobic biofilm reactor is a suitable technique for recycled pulp and paper wastewater (RPPW) treatment. The reactor shows high performances in terms of process stability, removal efficiency (> 70%) and biogas production.<br><br>CONCLUSION: Anaerobic digestion is an efficient waste treatment technology that uses natural anaerobic decomposition to reduce the volume of waste while producing biogas. However, research is needed to strengthen microbial metabolism, biochemistry and the functioning of the rector to improve biogas production. The RPPW AD experiment with biofilm digester technology was stable throughout the operation period. The digester knows an overloaded in the last phase of the experiment which leads to an inhibition of biogas production.},
}
@article {pmid31599128,
year = {2019},
author = {Turner, ME and Huynh, K and Carney, OV and Gross, D and Carroll, RK and Ahn, SJ and Rice, KC},
title = {Genomic instability of TnSMU2 contributes to Streptococcus mutans biofilm development and competence in a cidB mutant.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e934},
doi = {10.1002/mbo3.934},
pmid = {31599128},
issn = {2045-8827},
support = {1161177//National Science Foundation/ ; DE025237/NH/NIH HHS/United States ; DE025237/DE/NIDCR NIH HHS/United States ; //University of Florida/ ; },
abstract = {Streptococcus mutans is a key pathogenic bacterium in the oral cavity and a primary contributor to dental caries. The S. mutans Cid/Lrg system likely contributes to tolerating stresses encountered in this environment as cid and/or lrg mutants exhibit altered oxidative stress sensitivity, genetic competence, and biofilm phenotypes. It was recently noted that the cidB mutant had two stable colony morphologies: a &quot;rough&quot; phenotype (similar to wild type) and a &quot;smooth&quot; phenotype. In our previously published work, the cidB rough mutant exhibited increased sensitivity to oxidative stress, and RNAseq identified widespread transcriptomic changes in central carbon metabolism and oxidative stress response genes. In this current report, we conducted Illumina-based genome resequencing of wild type, cidB rough, and cidB smooth mutants and compared their resistance to oxidative and acid stress, biofilm formation, and competence phenotypes. Both cidB mutants exhibited comparable aerobic growth inhibition on agar plates, during planktonic growth, and in the presence of 1 mM hydrogen peroxide. The cidB smooth mutant displayed a significant competence defect in BHI, which was rescuable by synthetic CSP. Both cidB mutants also displayed reduced XIP-mediated competence, although this reduction was more pronounced in the cidB smooth mutant. Anaerobic biofilms of the cidB smooth mutant displayed increased propidium iodide staining, but corresponding biofilm CFU data suggest this phenotype is due to cell damage and not increased cell death. The cidB rough anaerobic biofilms showed altered structure relative to wild type (reduced biomass and average thickness) which correlated with decreased CFU counts. Sequencing data revealed that the cidB smooth mutant has a unique &quot;loss of read coverage&quot; of ~78 kb of DNA, corresponding to the genomic island TnSMU2 and genes flanking its 3' end. It is therefore likely that the unique biofilm and competence phenotypes of the cidB smooth mutant are related to its genomic changes in this region.},
}
@article {pmid31594958,
year = {2019},
author = {Liu, W and Tian, XQ and Wei, JW and Ding, LL and Qian, W and Liu, Z and Wang, FF},
title = {Author Correction: BsmR degrades c-di-GMP to modulate biofilm formation of nosocomial pathogen Stenotrophomonas maltophilia.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {14778},
doi = {10.1038/s41598-019-43380-7},
pmid = {31594958},
issn = {2045-2322},
abstract = {A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.},
}
@article {pmid31593452,
year = {2019},
author = {Chen, H and Luo, J and Liu, S and Yuan, Z and Guo, J},
title = {Microbial Methane Conversion to Short-chain Fatty Acids Using Various Electron Acceptors in Membrane Biofilm Reactors.},
journal = {Environmental science &amp; technology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.est.8b06767},
pmid = {31593452},
issn = {1520-5851},
abstract = {Given our vast methane reserves and the forecasted shortage of crude oil in the not too distant future, the conversion of methane into value-added liquid chemicals or fuels would be beneficial. The generated chemicals or fuels could augment the petroleum-dominated chemical market, and also satisfy the increasing demand for transportation fuels. While methane bioconversion to liquid chemicals has just been reported recently, there is limited understanding of the process. This study aims to clarify the potential electron acceptors that could support the process. Here we operated four membrane biofilm reactors (MBfRs) fed with nitrate, nitrite, oxygen at a relatively low rate and oxygen at a relatively high rate, respectively, to study if they can support methane bioconversion to short-chain fatty acids (SCFAs), and the associated microbiological features. All tested electron acceptors facilitated methane bioconversion to SCFAs (ranging from 1.1 to 36.7 mg acetate L-1 d-1, or 3.4 to 114.6 mg acetate d-1 m-2 of biofilm). The carbon efficiency was estimated to be 7.9 ± 1.4% to 148.5 ± 1.3%, with an efficiency higher than 100% suggesting the assimilation of other carbon, very likely CO2, into the products. A low oxygen supply rate of 46.4 ± 2.3 mg O2 d-1 m-2 was found to be the most favourable among all the electron conditions provided according to the SCFAs production rate and also the carbon utilization efficiency. Microbial characterization revealed that completely different communities evolved in the respective reactors, suggesting diverse microbial pathways exist for methane bioconversion into value-added chemicals.},
}
@article {pmid31590609,
year = {2019},
author = {Diaz, PI and Valm, AM},
title = {Microbial Interactions in Oral Communities Mediate Emergent Biofilm Properties.},
journal = {Journal of dental research},
volume = {},
number = {},
pages = {22034519880157},
doi = {10.1177/0022034519880157},
pmid = {31590609},
issn = {1544-0591},
abstract = {Oral microbial communities are extraordinarily complex in taxonomic composition and comprise interdependent biological systems. The bacteria, archaea, fungi, and viruses that thrive within these communities engage in extensive cell-cell interactions, which are both beneficial and antagonistic. Direct physical interactions among individual cells mediate large-scale architectural biofilm arrangements and provide spatial proximity for chemical communication and metabolic cooperation. In this review, we summarize recent work in identifying specific molecular components that mediate cell-cell interactions and describe metabolic interactions, such as cross-feeding and exchange of electron acceptors and small molecules, that modify the growth and virulence of individual species. We argue, however, that although pairwise interaction models have provided useful information, complex community-like systems are needed to study the properties of oral communities. The networks of multiple synergistic and antagonistic interactions within oral biofilms give rise to the emergent properties of persistence, stability, and long-range spatial structure, with these properties mediating the dysbiotic transitions from health to oral diseases. A better understanding of the fundamental properties of interspecies networks will lead to the development of effective strategies to manipulate oral communities.},
}
@article {pmid31584765,
year = {2019},
author = {García, A and Martínez, C and Juárez, RI and Téllez, R and Paredes, MA and Herrera, MDR and Giono, S},
title = {Methicillin resistance and biofilm production in clinical isolates of Staphylococcus aureus and coagulase-negative Staphylococcus in México.},
journal = {Biomedica : revista del Instituto Nacional de Salud},
volume = {39},
number = {3},
pages = {513-523},
doi = {10.7705/biomedica.4131},
pmid = {31584765},
issn = {0120-4157},
}
@article {pmid31589910,
year = {2019},
author = {Miryala, S and Makala, H and Yadavali, SP and Venkatasubramanian, U and Subbaiah, N and Srinandan, CS},
title = {Disperse red 15 (DR15) impedes biofilm formation of uropathogenic Escherichia coli.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103772},
doi = {10.1016/j.micpath.2019.103772},
pmid = {31589910},
issn = {1096-1208},
abstract = {Catheter associated urinary tract infection (CAUTI) is a highly prevalent hospital-acquired infection that is predominantly caused by uropathogenic Escherichia coli (UPEC). It adheres on catheter surface using type I pili as the initial step of pathogenesis that progresses to form biofilm. In this study, potential inhibitors against FimH adhesin of type I pili were screened computationally that yielded ten compounds. These were further validated in vitro against adhesion and biofilm formation. The compounds, 1-Amino-4-hydroxyanthraquinone (Disperse Red 15 or DR15) and 4-(4'-chloro-4-biphenylylsulfonylamino) benzoic acid (CB1) impaired adhesion and biofilm formation without inhibiting the planktonic growth. Also, both compounds inhibited cell assemblages like autoaggregation and swarming motility by unknown mechanisms. DR15 was further derivatized into N-(4-hydroxy-9,10-dioxo-9,10-dihydroanthracen-1-yl) undec-10-enamide that self-assembled with linseed oil, which was used as the coating material on urinary Foley catheters. The thin-film coating on the catheter did not leach when incubated in artificial urine and effectively restricted biofilm formation of UPEC. Altogether, the thin-film coating of urinary catheter with DR15 inhibited biofilm formation of UPEC and this application could potentially help to reduce CAUTI incidents in healthcare facilities.},
}
@article {pmid31589311,
year = {2019},
author = {Silva, MOD and Pernthaler, J},
title = {Priming of microcystin degradation in carbon-amended membrane biofilm communities is promoted by oxygen limited conditions.},
journal = {FEMS microbiology ecology},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsec/fiz157},
pmid = {31589311},
issn = {1574-6941},
abstract = {Microbial biofilms are an important element of gravity-driven membrane (GDM) filtration systems for decentralized drinking water production. Mature biofilms fed with biomass from the toxic cyanobacterium Microcystis aeruginosa efficiently remove the cyanotoxin microcystin (MC). MC degradation can be 'primed' by prior addition of biomass from a non-toxic M. aeruginosa strain. Increased proportions of bacteria with an anaerobic metabolism in M. aeruginosa-fed biofilms suggest that this 'priming' could be due to higher productivity and the resulting changes in habitat conditions. We, therefore, investigated GDM systems amended with the biomass of toxic [WT] or non-toxic [MUT] M. aeruginosa strains, of diatoms [DT], or with starch solution (ST). After 25 days, these treatments were changed to receiving toxic cyanobacterial biomass. MC degradation established significantly more rapidly in MUT and ST than in DT. Oxygen measurements suggested that this was due to oxygen limited conditions in MUT and ST already prevailing before addition of MC-containing biomass. Moreover, the microbial communities in the initial ST biofilms featured high proportions of facultative anaerobic taxa, whereas aerobes dominated in DT biofilms. Thus, the 'priming' of MC degradation in mature GDM biofilms seems to be related to the prior establishment of oxygen limited conditions mediated by higher productivity.},
}
@article {pmid31589240,
year = {2019},
author = {Favre, L and Ortalo-Magné, A and Kerloch, L and Pichereaux, C and Misson, B and Briand, JF and Garnier, C and Culioli, G},
title = {Metabolomic and proteomic changes induced by growth inhibitory concentrations of copper in the biofilm-forming marine bacterium Pseudoalteromonas lipolytica.},
journal = {Metallomics : integrated biometal science},
volume = {},
number = {},
pages = {},
doi = {10.1039/c9mt00184k},
pmid = {31589240},
issn = {1756-591X},
abstract = {Copper is an essential element for living cells but this metal is present in some marine environments at such high concentrations that it can be toxic for numerous organisms. In polluted areas, marine organisms may develop specific adaptive responses to prevent cell damage. To investigate the influence of copper on the metabolism of a single organism, a dual approach combining metabolomics and proteomics was undertaken on the biofilm-forming bacterial strain Pseudoalteromonas lipolytica TC8. In order to highlight differential adaptation according to the phenotype, the response of P. lipolytica TC8 to copper stress was studied in planktonic and biofilm culture modes under growth inhibitory copper concentrations. As expected, copper exposure led to the induction of defense and detoxification mechanisms. Specific metabolite and protein profiles were thus observed in each condition (planktonic vs. biofilm and control vs. copper-treated cultures). Copper exposure seems to induce drastic changes in the lipid composition of the bacterial cell membrane and to modulate the abundance of proteins functionally known to be involved in copper cell homeostasis in both planktonic and biofilm culture modes. Much more proteins differentially expressed after copper treatment were observed in biofilms than in planktonic cells, which could indicate a more heterogeneous response of biofilm cells to this metallic stress.},
}
@article {pmid31586764,
year = {2019},
author = {Liu, X and Zhuo, S and Jing, X and Yuan, Y and Rensing, C and Zhou, S},
title = {Flagella act as Geobacter biofilm scaffolds to stabilize biofilm and facilitate extracellular electron transfer.},
journal = {Biosensors &amp; bioelectronics},
volume = {146},
number = {},
pages = {111748},
doi = {10.1016/j.bios.2019.111748},
pmid = {31586764},
issn = {1873-4235},
abstract = {Flagella are widely expressed in electroactive biofilms; however, their actual role is unknown. To understand the role of flagella, two Geobacter sulfurreducens strains (KN400 and PCA, with and without flagella, respectively) were selected. We restored flagellum expression in trans in strain PCA and prevented flagellum expression in strain KN400. Electrochemical results showed that flagellum restoration in strain PCA promoted current generation, while flagellum deletion in strain KN400 impaired current production. However, the expression of conductive pili and outer surface c-type cytochromes was not affected. Further microscopic analyses demonstrated that flagella promoted the formation of thicker biofilms and served as biofilm matrix scaffolds to accommodate more extracellular cytochromes with an orderly arrangement, which increased the electron diffusion rate within the biofilm. Our findings reveal an unprecedented structural role for flagella in stabilizing electroactive biofilms and highlight the importance of cytochromes in electron transfer across biofilms, which will deepen our understanding of biofilm conductivity.},
}
@article {pmid31586475,
year = {2019},
author = {Shi, N and Gao, Y and Yin, D and Song, Y and Kang, J and Li, X and Zhang, Z and Feng, X and Duan, J},
title = {The effect of the sub-minimal inhibitory concentration and the concentrations within resistant mutation window of ciprofloxacin on MIC, swimming motility and biofilm formation of Pseudomonas aeruginosa.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103765},
doi = {10.1016/j.micpath.2019.103765},
pmid = {31586475},
issn = {1096-1208},
abstract = {OBJECTIVE: To explore the effect of sub-minimal inhibitory concentration (sub-MIC) and concentrations within resistant mutation window (MSW) of ciprofloxacin (CIP) on minimal inhibitory concentration (MIC), swimming motility and biofilm formation of Pseudomonas aeruginosa, and also to investigate the correlation between swimming motility and genes expression of lasI, lasR, rhlI, rhlR and pqsR.<br><br>METHODS: The collected strains were incubated under four different concentrations for 5 days. The MIC and mutant prevention concentration (MPC) were measured by the agar dilution method. The diameter of turbid cycle was used to signify the swimming motility. The biofilm formation was measured by the crystal violet stain method. The genes expression of lasI, lasR, rhlI, rhlR and pqsR were measured by RT-PCR.<br><br>RESULTS: A total of 11 P. aeruginosa which sensitive to CIP were collected. The incubation within concentrations of MSW made MICs to CIP increased more obviously than under sub-MIC (P < 0.05). The swimming motility showed a trend of being inhibited first and then promoted over time under sub-MIC (P < 0.05), whereas, it was promoted under concentrations within MSW. The biofilm formation was significantly promoted under the concentration of 4×MIC (P < 0.05). Under sub-MIC, the genes expression of rhlR and pqsR had a middle level positive correlation with the promotion of the swimming motility (P < 0.05, r = 0.788 and P < 0.05, r = 0.652, respectively).<br><br>CONCLUSIONS: Under the concentration of sub-MIC (0.5×MIC) and the concentrations within MSW (1×MIC, 2×MIC and 4×MIC), the effect of CIP on MICs, swimming motility and biofilm formation of P.aeruginosa was quite different. The genes expression of rhlR and pqsR had a middle level positive correlation with the promotion of the swimming motility.},
}
@article {pmid31585061,
year = {2019},
author = {Thompson, AF and English, EL and Nock, AM and Willsey, GG and Eckstrom, K and Cairns, B and Bavelock, M and Tighe, SW and Foote, A and Shulman, H and Pericleous, A and Gupta, S and Kadouri, DE and Wargo, MJ},
title = {Characterizing species interactions that contribute to biofilm formation in a multispecies model of a potable water bacterial community.},
journal = {Microbiology (Reading, England)},
volume = {},
number = {},
pages = {},
doi = {10.1099/mic.0.000849},
pmid = {31585061},
issn = {1465-2080},
abstract = {Microbial biofilms are ubiquitous in drinking water systems, yet our understanding of drinking water biofilms lags behind our understanding of those in other environments. Here, a six-member model bacterial community was used to identify the interactions and individual contributions of each species to community biofilm formation. These bacteria were isolated from the International Space Station potable water system and include Cupriavidus metallidurans, Chryseobacterium gleum, Ralstonia insidiosa, Ralstonia pickettii, Methylorubrum (Methylobacterium) populi and Sphingomonas paucimobilis, but all six species are common members of terrestrial potable water systems. Using reconstituted assemblages, from pairs to all 6 members, community biofilm formation was observed to be robust to the absence of any single species and only removal of the C. gleum/S. paucimobilis pair, out of all 15 possible 2-species subtractions, led to loss of community biofilm formation. In conjunction with these findings, dual-species biofilm formation assays supported the view that the contribution of C. gleum to community biofilm formation was dependent on synergistic biofilm formation with either R. insidiosa or C. metallidurans. These data support a model of multiple, partially redundant species interactions to generate robustness in biofilm formation. A bacteriophage and multiple predatory bacteria were used to test the resilience of the community to the removal of individual members in situ, but the combination of precise and substantial depletion of a single target species was not achievable. We propose that this assemblage can be used as a tractable model to understand the molecular bases of the interactions described here and to decipher other functions of drinking water biofilms.},
}
@article {pmid31585041,
year = {2019},
author = {Xi, Y and Wang, Y and Gao, J and Xiao, Y and Du, J},
title = {Dual Corona Vesicles with Intrinsic Antibacterial and Enhanced Antibiotic Delivery Capabilities for Effective Treatment of Biofilm-Induced Periodontitis.},
journal = {ACS nano},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsnano.9b03237},
pmid = {31585041},
issn = {1936-086X},
abstract = {Periodontitis is a common disease caused by plaque biofilms, which are important pathogenic factors of many diseases and may be eradicated by antibiotic therapy. However, low dose antibiotic therapy is a complicated challenge for eradiating biofilms as hundreds (even thousands) of times higher concentrations of antibiotics are needed than killing planktonic bacteria. Polymer vesicles may solve these problems via effective antibiotic delivery into biofilms, but traditional single corona vesicles lack the multifunctionalities essential for biofilm eradication. In this paper, we aim to effectively treat biofilm-induced periodontitis using much lower concentrations of antibiotics than traditional antibiotic therapy by designing a multifunctional dual corona vesicle with intrinsic antibacterial and enhanced antibiotic delivery capabilities. This vesicle is co-assembled from two block copolymers, poly(ε-caprolactone)-block-poly(lysine-stat-phenylalanine) [PCL-b-P(Lys-stat-Phe)] and poly(ethylene oxide)-block-poly(ε-caprolactone) [PEO-b-PCL]. Both PEO and P(Lys-stat-Phe) coronas have their specific functions: PEO endows vesicles with protein repelling ability to penetrate extracellular polymeric substances (EPS) in biofilms ('stealthy' coronas), while P(Lys-stat-Phe) provides vesicles with positive charges and broad spectrum intrinsic antibacterial activity. As a result, the dosage of antibiotics can be reduced by 50% when encapsulated in the dual corona vesicles to eradicate Escherichia coli (E. coli) or Staphylococcus aureus (S. aureus) biofilms. Furthermore, effective in vivo treatment has been achieved from a rat periodontitis model, as confirmed by significantly reduced dental plaque, and alleviated inflammation. Overall, this 'stealthy' and antibacterial dual corona vesicle demonstrates a fresh insight for improving the antibiofilm efficiency of antibiotics and combating the serious threat of biofilm-associated diseases.},
}
@article {pmid31584713,
year = {2019},
author = {Soares Dos Santos, DM and Braga, AS and Rizk, M and Wiegand, A and Magalhães, AC},
title = {Comparison between micro-computed tomography and transverse microradiography of sound dentine treated with fluorides and demineralized by microcosm biofilm.},
journal = {European journal of oral sciences},
volume = {},
number = {},
pages = {},
doi = {10.1111/eos.12656},
pmid = {31584713},
issn = {1600-0722},
support = {MWK INST 1525/39-1 FUGG//Deutsche Forschungsgemeinschaft/ ; 2017/13386-5//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 2017/00556-0//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; },
abstract = {The study aimed to apply micro-computed tomography (micro-CT) and transverse microradiography (TMR) to measure dentine demineralization and to test the preventive effect of titanium tetrafluoride (TiF4) under microcosm biofilm. Sound dentine specimens from bovine root were treated for 6 h with: (i) 4.0% titanium tetrafluoride (TiF4) varnish [pH 1.0, 2.45% fluoride (F-); (ii) 5.42% sodium fluoride (NaF) varnish (pH 5.0, 2.45% F); (iii) 2% chlorhexidine (CHX) gel (pH 7.0); (iv) placebo varnish (pH 5.0); or (v) no agent (untreated). Dentine specimens were then exposed to human saliva mixed with McBain saliva for 8 h. Thereafter, McBain saliva containing 0.2% sucrose was applied daily, for 5 d, onto dentine specimens to stimulate formation of microcosm biofilm. Although a high correlation was found between the results of both methods regarding integrated mineral loss, the results of the methods did not show good agreement in Bland-Altman plots, with significant biases in calculations of lesion depth. Fluoride varnishes were able to reduce dentine demineralization (P < 0.05), while CHX failed to do so. Fluorides are still the best option to reduce dentine demineralization. Micro-CT may be used to measure dentine mineral loss, but not the lesion depth, for which TMR is superior.},
}
@article {pmid31584030,
year = {2019},
author = {Yadav, S and Sachdev, V and Malik, M and Chopra, R},
title = {Effect of three different compositions of topical fluoride varnishes with and without prior oral prophylaxis on Streptococcus mutans count in biofilm samples of children aged 2-8 years: A randomized controlled trial.},
journal = {Journal of the Indian Society of Pedodontics and Preventive Dentistry},
volume = {37},
number = {3},
pages = {286-291},
doi = {10.4103/JISPPD.JISPPD_62_19},
pmid = {31584030},
issn = {1998-3905},
abstract = {Background: Various strategies for controlling caries focus on disrupting the interaction between risk factors. Of these, fluoride varnish has been shown to reduce the colony-forming (CFU) units and water-insoluble extracellular polysaccharide amount. Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and xylitol-containing fluoride varnishes have recently gained importance as caries-protective fluoride varnishes.<br><br>Aim: This study aims to assess and compare the reduction in Streptococcus mutans count in biofilm samples after topical application of three different fluoride varnishes and to evaluate the effect of oral prophylaxis prior to fluoride varnish application.<br><br>Materials and Methods: Sixty healthy children with no active caries, in the age group of 2-8 years, were randomly divided into Group A = fluoride varnish containing CPP-ACP; Group B = fluoride varnish containing xylitol; and Group C = fluoride varnish with 0.9% difluorosilane; further, the groups were divided into two subgroups, namely A1, B1, and C1 with prior oral prophylaxis and A2, B2, and C2 without oral prophylaxis. Plaque samples were collected at baseline, 1st month, and 3rd month; cultured; and incubated, and CFU/ml was calculated.<br><br>Results: Data were compiled, and CFU/ml was analyzed by independent t-test, paired t-test, and one-way ANOVA. There was no statistical difference between the fluoride groups. Furthermore, no statistically significant difference was seen between the subgroups.<br><br>Conclusion: Fluoride varnish containing CPP-ACP showed higher reduction in S. mutans count followed by xylitol-containing fluoride varnish and Fluor Protector®. There was no effect of prior oral prophylaxis on the efficacy of fluoride varnish.},
}
@article {pmid31583791,
year = {2019},
author = {Dundas, AA and Sanni, O and Dubern, JF and Dimitrakis, G and Hook, AL and Irvine, DJ and Williams, P and Alexander, MR},
title = {Validating a Predictive Structure-Property Relationship by Discovery of Novel Polymers which Reduce Bacterial Biofilm Formation.},
journal = {Advanced materials (Deerfield Beach, Fla.)},
volume = {},
number = {},
pages = {e1903513},
doi = {10.1002/adma.201903513},
pmid = {31583791},
issn = {1521-4095},
support = {EP/N006615/1//Engineering and Physical Sciences Research Council/ ; 103882/WT_/Wellcome Trust/United Kingdom ; 103884/WT_/Wellcome Trust/United Kingdom ; //University of Nottingham/ ; },
abstract = {Synthetic materials are an everyday component of modern healthcare yet often fail routinely as a consequence of medical-device-centered infections. The incidence rate for catheter-associated urinary tract infections is between 3% and 7% for each day of use, which means that infection is inevitable when resident for sufficient time. The O'Neill Review on antimicrobial resistance estimates that, left unchecked, ten million people will die annually from drug-resistant infections by 2050. Development of biomaterials resistant to bacterial colonization can play an important role in reducing device-associated infections. However, rational design of new biomaterials is hindered by the lack of quantitative structure-activity relationships (QSARs). Here, the development of a predictive QSAR is reported for bacterial biofilm formation on a range of polymers, using calculated molecular descriptors of monomer units to discover and exemplify novel, biofilm-resistant (meth-)acrylate-based polymers. These predictions are validated successfully by the synthesis of new monomers which are polymerized to create coatings found to be resistant to biofilm formation by six different bacterial pathogens: Pseudomonas aeruginosa, Proteus mirabilis, Enterococcus faecalis, Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus.},
}
@article {pmid31583108,
year = {2019},
author = {Guilhen, C and Miquel, S and Charbonnel, N and Joseph, L and Carrier, G and Forestier, C and Balestrino, D},
title = {Colonization and immune modulation properties of Klebsiella pneumoniae biofilm-dispersed cells.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {25},
doi = {10.1038/s41522-019-0098-1},
pmid = {31583108},
issn = {2055-5008},
abstract = {Biofilm-dispersal is a key determinant for further dissemination of biofilm-embedded bacteria. Recent evidence indicates that biofilm-dispersed bacteria have transcriptional features different from those of both biofilm and planktonic bacteria. In this study, the in vitro and in vivo phenotypic properties of Klebsiella pneumoniae cells spontaneously dispersed from biofilm were compared with those of planktonic and sessile cells. Biofilm-dispersed cells, whose growth rate was the same as that of exponential planktonic bacteria but significantly higher than those of sessile and stationary planktonic forms, colonized both abiotic and biotic surfaces more efficiently than their planktonic counterparts regardless of their initial adhesion capabilities. Microscopy studies suggested that dispersed bacteria initiate formation of microcolonies more rapidly than planktonic bacteria. In addition, dispersed cells have both a higher engulfment rate and better survival/multiplication inside macrophages than planktonic cells and sessile cells. In an in vivo murine pneumonia model, the bacterial load in mice lungs infected with biofilm-dispersed bacteria was similar at 6, 24 and 48 h after infection to that of mice lungs infected with planktonic or sessile bacteria. However, biofilm-dispersed and sessile bacteria trend to elicit innate immune response in lungs to a lesser extent than planktonic bacteria. Collectively, the findings from this study suggest that the greater ability of K. pneumoniae biofilm-dispersed cells to efficiently achieve surface colonization and to subvert the host immune response confers them substantial advantages in the first steps of the infection process over planktonic bacteria.},
}
@article {pmid31581038,
year = {2019},
author = {Henning, N and Falås, P and Castronovo, S and Jewell, KS and Bester, K and Ternes, TA and Wick, A},
title = {Biological transformation of fexofenadine and sitagliptin by carrier-attached biomass and suspended sludge from a hybrid moving bed biofilm reactor.},
journal = {Water research},
volume = {167},
number = {},
pages = {115034},
doi = {10.1016/j.watres.2019.115034},
pmid = {31581038},
issn = {1879-2448},
abstract = {Laboratory-scale experiments were conducted to investigate the (bio)transformation of the antidiabetic sitagliptin (STG) and the antihistamine fexofenadine (FXF) during wastewater treatment. As inoculum either attached-growth on carriers or suspended sludge from a hybrid moving bed biofilm reactor (HMBBR) was used. Both target compounds were incubated in degradation experiments and quantified via LC-MS/MS for degradation kinetics. Furthermore transformation products (TPs) were analyzed via high resolution mass spectrometry (HRMS). Structural elucidation of the TPs was based on the high resolution molecular ion mass to propose a molecular formula and on MS2 fragmentation to elucidate the chemical structure of the TPs. In total, 22 TPs (9 TPs for STG and 13 TPs for FXF) were detected in the experiments with STG and FXF. For all TPs, chemical structures could be proposed. STG was mainly transformed via amide hydrolysis and conjugation of the primary amine moiety. In contrast, FXF was predominantly transformed by oxidative reactions such as oxidation (dehydrogenation) and hydroxylation. Furthermore, FXF was removed significantly faster in contact with carriers compared to suspended sludge, whereas STG was degraded slightly faster in contact with suspended sludge. Moreover, the primary TP of FXF was also degraded faster in contact with carriers leading to higher proportions of secondary TPs. Thus, the microbial community of both carriers and suspended sludge catalyzed the same primary transformation reactions but the transformation kinetics of FXF and the formation/degradation of FXF TPs were considerably higher in contact with carrier-attached biomass. The primary degradation of both target compounds in pilot- and full-scale conventional activated sludge (CAS) and MBBR reactors reached 42 and 61% for FXF and STG, respectively. Up to three of the identified TPs of FXF and 8 TPs of STG were detected in the effluents of pilot- and full-scale CAS and MBBR.},
}
@article {pmid31580958,
year = {2019},
author = {Arteaga, V and Lamas, A and Regal, P and Vázquez, B and Miranda, JM and Cepeda, A and Franco, CM},
title = {Antimicrobial activity of apitoxin from Apis mellifera in Salmonella enterica strains isolated from poultry and its effects on motility, biofilm formation and gene expression.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103771},
doi = {10.1016/j.micpath.2019.103771},
pmid = {31580958},
issn = {1096-1208},
abstract = {Salmonella is a major global food-borne pathogen. One of the main concerns related to Salmonella and other food-borne pathogens is their capacity to acquire antimicrobial resistance and produce biofilms. Due to the increased resistance to common antimicrobials used to treat livestock animals and human infections, the discovery of new antimicrobial substances is one of the main challenges in microbiological research. An additional challenge is the development of new methods and substances to inhibit and destruct biofilms. We determined the antimicrobial and antibiofilm activities of apitoxin in 16 Salmonella strains isolated from poultry. In addition, the effect of apitoxin on Salmonella motility and the expression of biofilm- and virulence-related genes was evaluated. The minimum inhibitory concentrations (MIC) of apitoxin ranged from 1,024-256 μg/mL, with 512 μg/mL being the most common. Sub-inhibitory concentrations of apitoxin significantly reduced biofilm formation in 14 of the 16 Salmonella strains tested, with significant increases in motility. MIC concentrations of apitoxin destroyed the pre-formed biofilm by 27.66-68.22% (47.00% ± 10.91). The expression of biofilm- and virulence-related genes and small RNAs was differentially regulated according to the strain and the presence of apitoxin. The transcription of the small RNAs dsrA and csrB, related to antimicrobial resistance, was upregulated in the presence of apitoxin. We suggest that apitoxin is a potential antimicrobial substance that could be used in combination with other substances to develop new drugs and sanitizers against food-borne pathogens.},
}
@article {pmid31579334,
year = {2019},
author = {Kamiya, M and Mori, T and Nomura, M and Inagaki, T and Nonogaki, T and Nagatsu, A and Yamagishi, Y and Mikamo, H and Ikeda, Y},
title = {Tradescantia pallida extract inhibits biofilm formation in Pseudomonas aeruginosa.},
journal = {Nagoya journal of medical science},
volume = {81},
number = {3},
pages = {439-452},
doi = {10.18999/nagjms.81.3.439},
pmid = {31579334},
issn = {2186-3326},
abstract = {Pseudomonas aeruginosa is capable of biofilm formation. In this study, we investigated the effects of aqueous Tradescantia pallida extract on Pseudomonas aeruginosa growth and biofilm formation. Aqueous Tradescantia pallida extracts significantly inhibited both bacterial growth and biofilm formation. However, methanolic Tradescantia pallida extracts inhibited neither. Aqueous Tradescantia pallida extracts were deactivated by heating but were not deactivated by light exposure. The ingredients retained the inhibitory effect on the bacterial growth and biofilm formation after ultrafiltration of aqueous Tradescantia pallida extract. Furthermore, polyphenol-rich Tradescantia pallida extracts inhibited bacterial growth, thus, polyphenols are possible to be an active ingredient. We observed the biofilm by scanning electron microscopy, and quantitative and qualitative differences in the biofilm and cells morphology. Interestingly, the biofilm treated aqueous Tradescantia pallida extracts remained premature. We postulated that premature biofilm formation was due to the inhibition of swarming motility. Indeed, aqueous Tradescantia pallida extracts inhibited swarming motility. These results demonstrate that Peudomonas aeruginosa growth and biofilm formation are inhibited by aqueous Tradescantia pallida extracts.},
}
@article {pmid31578154,
year = {2019},
author = {Shi, YJ and Fang, QJ and Huang, HQ and Gong, CG and Hu, YH},
title = {HutZ is required for biofilm formation and contributes to the pathogenicity of Edwardsiella piscicida.},
journal = {Veterinary research},
volume = {50},
number = {1},
pages = {76},
doi = {10.1186/s13567-019-0693-4},
pmid = {31578154},
issn = {1297-9716},
support = {41476138//National Natural Science Foundation of China/ ; },
abstract = {Edwardsiella piscicida is a severe fish pathogen. Haem utilization systems play an important role in bacterial adversity adaptation and pathogenicity. In this study, a speculative haem utilization protein, HutZEp, was characterized in E. piscicida. hutZEp is encoded with two other genes, hutW and hutX, in an operon that is similar to the haem utilization operon hutWXZ identified in V. cholerae. However, protein activity analysis showed that HutZEp is probably not related to hemin utilization. To explore the biological role of HutZEp, a markerless hutZEp in-frame mutant strain, TX01ΔhutZ, was constructed. Deletion of hutZEp did not significantly affect bacterial growth in normal medium, in iron-deficient conditions, or in the presence of haem but significantly retarded bacterial biofilm growth. The expression of known genes related to biofilm growth was not affected by hutZEp deletion, which indicated that HutZEp was probably a novel factor promoting biofilm formation in E. piscicida. Compared to the wild-type TX01, TX01ΔhutZ exhibited markedly compromised tolerance to acid stress and host serum stress. Pathogenicity analysis showed that inactivation of hutZEp significantly impaired the ability of E. piscicida to invade and reproduce in host cells and to infect host tissue. In contrast to TX01, TX01ΔhutZ was defective in blocking host macrophage activation. The expression of hutZEp was directly regulated by the ferric uptake regulator Fur. This study is the first functional characterization of HutZ in a fish pathogen, and these findings suggested that HutZEp is essential for E. piscicida biofilm formation and contributes to host infection.},
}
@article {pmid31575315,
year = {2019},
author = {Namgoong, S and Jung, SY and Han, SK and Kim, AR and Dhong, ES},
title = {Clinical experience with surgical debridement and simultaneous meshed skin grafts in treating biofilm-associated infection: an exploratory retrospective pilot study.},
journal = {Journal of plastic surgery and hand surgery},
volume = {},
number = {},
pages = {1-8},
doi = {10.1080/2000656X.2019.1673170},
pmid = {31575315},
issn = {2000-6764},
abstract = {Current treatment guidelines for biofilm-associated infections (BAI) recommend repeated sharp/surgical debridement followed by treatment with antimicrobial agents until the wound becomes self-sustaining in terms of a positive wound-healing trajectory. However, complete removal of a biofilm is unlikely, and biofilms reform rapidly. We have treated BAI in patients with chronic diabetic ulcers using a meshed skin graft combined with negative pressure wound therapy (NPWT) immediately after surgical debridement, rather than waiting until the development of clean and healthy granulation tissue; the purpose of this exploratory study was to report the clinical results of this treatment strategy. This retrospective study included 75 patients with chronic diabetic ulcers who were treated for BAI by using surgical debridement, simultaneous meshed skin grafts, and NPWT. Healing time along with the percentage of complete wound closure within 12 weeks were evaluated; bacteria isolated from the wounds and their relation to the wound healing rate were investigated. All 75 wounds healed successfully, and the mean time for complete wound healing was 3.5 ± 1.8 weeks. In particular, 76% of wounds healed uneventfully without graft loss. A mean of 3.3 bacterial colonies/wound were isolated; however, no significant difference in wound healing was observed between the monomicrobial and polymicrobial groups. This exploratory study suggests that surgical debridement and simultaneous meshed skin grafts combined with NPWT may be successfully used to combat BAI in patients with chronic diabetic ulcers. We look forward to larger pivotal studies to confirm or refute these initially promising findings.},
}
@article {pmid31574542,
year = {2019},
author = {Meyer, F and Enax, J},
title = {Hydroxyapatite in Oral Biofilm Management.},
journal = {European journal of dentistry},
volume = {13},
number = {2},
pages = {287-290},
doi = {10.1055/s-0039-1695657},
pmid = {31574542},
issn = {1305-7456},
abstract = {Particulate hydroxyapatite, Ca5 (PO4)3 (OH), shows a good biocompatibility and is used as a biomimetic ingredient in dental care formulations due to its similarity to human enamel. Numerous studies show its efficiency, for example, in reducing dentin hypersensitivity, and in the remineralization of enamel and dentin. In addition, oral care products with hydroxyapatite improve periodontal health under in vivo conditions. This review article summarizes data on the effects of hydroxyapatite particles in oral biofilm management. Two databases (PubMed and SciFinder) were searched for studies using specific search terms. In contrast to frequently used antibacterial agents for biofilm control, such as chlorhexidine, stannous salts, and quaternary ammonium salts, hydroxyapatite particles in oral care products lead to a reduction in bacterial attachment to enamel surfaces in situ without having pronounced antibacterial effects or showing unwanted side effects such as tooth discoloration. Furthermore, antibacterial agents might lead to dysbiosis of the oral ecology, which was recently discussed regarding pros and cons. Remarkably, the antiadherent properties of hydroxyapatite particles are comparable to those of the gold standard in the field of oral care biofilm management, chlorhexidine in situ. Although biomimetic strategies have been less well analyzed compared with commonly used antibacterial agents in oral biofilm control, hydroxyapatite particles are a promising biomimetic alternative or supplement for oral biofilm management.},
}
@article {pmid31574321,
year = {2019},
author = {Fugolin, AP and Dobson, A and Huynh, V and Mbiya, W and Navarro, O and Franca, CM and Logan, M and Merritt, JL and Ferracane, JL and Pfeifer, CS},
title = {Antibacterial, Ester-Free Monomers: Polymerization Kinetics, Mechanical Properties, Biocompatibility and Anti-Biofilm Activity.},
journal = {Acta biomaterialia},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.actbio.2019.09.039},
pmid = {31574321},
issn = {1878-7568},
abstract = {OBJECTIVES: Quaternary ammonium (QA) methacrylate monomers have been extensively investigated and demonstrate excellent antibacterial properties. However, the presence of ester bonds makes them prone to degradation in the oral cavity. In this study, ester-free QA monomers based on meth-acrylamides were synthesized and screened for polymerization kinetics, mechanical properties and antibacterial effects.<br><br>MATERIALS AND METHODS: Tertiary quaternary ammonium acrylamides (AM) and methacrylamides (MAM) with alkyl side chain lengths of 9 and 14 carbons (C9 and C14) were synthesized and incorporated at 10 wt% into experimental composites based on BisGMA:TEGDMA (1:1), camphorquinone/ethyl-4-dimethylaminobenzoate (0.2/0.8 wt%) and 70 wt% barium glass fillers. Analogous methacrylate versions (MA) were used as controls. Degree of conversion (DC) and rate of polymerization (RP) during photoactivation (800 mW/cm2) were followed in real-time with near-IR. Flexural Strength (FS) and Modulus (E) were measured on 2 × 2 × 25 mm bars in 3-point bending after 24h dry storage and 7-day storage in water at 37°C. Antimicrobial properties and biofilm adhesion (fouling) were evaluated by bioluminescence (Luciferase Assay) and biofilm removal by water spray microjet impingement test, respectively. Cytotoxicity was assessed by MTT assay on dental pulp stem cells (DPSC). Data were analyzed with one-way ANOVA/Tukey's test (α=0.05).<br><br>RESULTS: DC was similar for all groups tested (∼70%). Both MAMs and C14-AM presented significantly lower RP. Under dry conditions, FS (110-120 MPa) and E (8-9 GPa) were similar for all groups. After water storage, all materials presented FS/E similar to the control, except for C14-AM (for FS) and C14-MAM (for E), which were lower. All C14 versions were strongly antibacterial, decreasing the titer counts of biofilm by more than two orders of magnitude in comparison to the control. C9 monomers did not present significant antibacterial nor antifouling properties. And biofilms had approximately equivalent adhesion on the C9 composites as on the control. Cytotoxicity did not show significant differences between the MA and AM versions and the control group.<br><br>CONCLUSIONS: C14-QA monomers based on methacrylates and meth-acrylamides present strong antibacterial properties, and in general, similar conversion/mechanical properties compared to the methacrylate control.},
}
@article {pmid31573125,
year = {2019},
author = {Romeu, MJ and Alves, P and Morais, J and Miranda, JM and de Jong, ED and Sjollema, J and Ramos, V and Vasconcelos, V and Mergulhão, FJ},
title = {Biofilm formation behaviour of marine filamentous cyanobacterial strains in controlled hydrodynamic conditions.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.14807},
pmid = {31573125},
issn = {1462-2920},
abstract = {Marine biofouling has severe economic impacts and cyanobacteria play a significant role as early surface colonizers. Despite this fact, cyanobacterial biofilm formation studies in controlled hydrodynamic conditions are scarce. In this work, computational fluid dynamics was used to determine the shear rate field on coupons that were placed inside the wells of agitated 12-well microtiter plates. Biofilm formation by three different cyanobacterial strains was assessed at two different shear rates (4 and 40 s-1) which can be found in natural ecosystems and using different surfaces (glass and perspex). Biofilm formation was higher under low shear conditions and differences obtained between surfaces were not always statistically significant. The hydrodynamic effect was more noticeable during the biofilm maturation phase rather than during initial cell adhesion and Optical Coherence Tomography showed that different shear rates can affect biofilm architecture. This study is particularly relevant given the cosmopolitan distribution of these cyanobacterial strains and the biofouling potential of these organisms. This article is protected by copyright. All rights reserved.},
}
@article {pmid31570700,
year = {2019},
author = {Jiao, Y and Tay, FR and Niu, LN and Chen, JH},
title = {Advancing antimicrobial strategies for managing oral biofilm infections.},
journal = {International journal of oral science},
volume = {11},
number = {3},
pages = {28},
doi = {10.1038/s41368-019-0062-1},
pmid = {31570700},
issn = {2049-3169},
abstract = {Effective control of oral biofilm infectious diseases represents a major global challenge. Microorganisms in biofilms exhibit increased drug tolerance compared with planktonic cells. The present review covers innovative antimicrobial strategies for controlling oral biofilm-related infections published predominantly over the past 5 years. Antimicrobial dental materials based on antimicrobial agent release, contact-killing and multi-functional strategies have been designed and synthesized for the prevention of initial bacterial attachment and subsequent biofilm formation on the tooth and material surface. Among the therapeutic approaches for managing biofilms in clinical practice, antimicrobial photodynamic therapy has emerged as an alternative to antimicrobial regimes and mechanical removal of biofilms, and cold atmospheric plasma shows significant advantages over conventional antimicrobial approaches. Nevertheless, more preclinical studies and appropriately designed and well-structured multi-center clinical trials are critically needed to obtain reliable comparative data. The acquired information will be helpful in identifying the most effective antibacterial solutions and the most optimal circumstances to utilize these strategies.},
}
@article {pmid31570396,
year = {2019},
author = {Lopes, AA and Yoshii, Y and Yamada, S and Nagakura, M and Kinjo, Y and Mizunoe, Y and Okuda, KI},
title = {Roles of lytic transglycosylases in biofilm formation and β-lactam resistance in methicillin-resistant Staphylococcus aureus.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01277-19},
pmid = {31570396},
issn = {1098-6596},
abstract = {Staphylococcus aureus is responsible for numerous community outbreaks and is one of the most frequent causes of nosocomial infections with significant morbidity and mortality. While the function of lytic transglycosylases (LTs) in relation to cell division, biofilm formation, and antibiotic resistance has been determined for several bacteria, their role in S. aureus remains largely unknown. The only known LTs in S. aureus are immunodominant staphylococcal antigen A (IsaA) and Staphylococcus epidermidis D protein (SceD). Our study demonstrates that, in a strain of methicillin-resistant S. aureus (MRSA), IsaA and SceD contribute differently to biofilm formation and β-lactam resistance. Deletion of isaA, but not sceD, led to decreased biofilm formation. Additionally, in isaA-deleted strains, β-lactam resistance was significantly decreased compared to that of wild-type strains. Plasmid-based expression of mecA, a major determinant of β-lactam resistance in MRSA, in an isaA-deleted strain did not restore β-lactam resistance, demonstrating that the β-lactam susceptibility phenotype is exhibited by isaA mutant regardless of the production level of PBP2a. Overall, our results suggest that IsaA is a potential therapeutic target for MRSA infections.},
}
@article {pmid31565797,
year = {2019},
author = {Wang, X and Kong, Y and Zhao, H and Yan, X},
title = {Dependence of the Bacillus subtilis biofilm expansion rate on phenotypes and the morphology under different growing conditions.},
journal = {Development, growth &amp; differentiation},
volume = {},
number = {},
pages = {},
doi = {10.1111/dgd.12627},
pmid = {31565797},
issn = {1440-169X},
support = {//Harvard University/ ; 11772047//The National Natural Science Foundation of China/ ; 11620101001//The National Natural Science Foundation of China/ ; 2017YFB1002701//National Key R&amp;D Program of China/ ; },
abstract = {Biofilms are communities of tightly associated bacteria encased in an extracellular matrix and attached to surfaces of various objects, such as liquid or solid surfaces. Here we use the multi-channel wide field stereo fluorescence microscope to characterize growth of the Bacillus subtilis biofilm, in which the bacterial strain was triple fluorescence labeled for three main phenotypes: motile, matrix producing and sporulating cells. We used the feature point matching approach analyzing time lapse experimental movies to study the biofilm expansion rate. We found that the matrix producing cells dominate the biofilm expansion, at the biofilm edge, the expansion rate of matrix producing cells was almost the same as the velocity of the whole biofilm; however, the motile and sporulating cells were nearly rest. We also found that the biofilm expansion rate evolution relates to cell differentiation and biofilm morphology, and other micro-environments can influence the biofilm growth, such as nutrient, substrate hardness and colony competition. From our work, we get a deeper understanding of the biofilm growth, which can help us to control and to further disperse the biofilm.},
}
@article {pmid31563809,
year = {2019},
author = {Han, C and Goodwine, J and Romero, N and Steck, KS and Sauer, K and Doiron, A},
title = {Enzyme-encapsulating polymeric nanoparticles: A potential adjunctive therapy in Pseudomonas aeruginosa biofilm-associated infection treatment.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {184},
number = {},
pages = {110512},
doi = {10.1016/j.colsurfb.2019.110512},
pmid = {31563809},
issn = {1873-4367},
abstract = {Pseudomonas aeruginosa is a pathogen known to be associated with a variety of diseases and conditions such as cystic fibrosis, chronic wound infections, and burn wound infections. A novel approach was developed to combat the problem of biofilm antibiotic tolerance by reverting biofilm bacteria back to the planktonic mode of growth. This reversion was achieved through the enzymatic depletion of available pyruvate using pyruvate dehydrogenase, which induced biofilm bacteria to disperse from the surface-associated mode of growth into the surrounding environment. However, direct use of the enzyme in clinical settings is not practical as the enzyme is susceptible to denaturation under various storage conditions. We hypothesize that by encapsulating pyruvate dehydrogenase into degradable, biocompatible poly(lactic-co-glycolic) acid nanoparticles, the activity of the enzyme can be extended to deplete available pyruvate and induce dispersion of mature Pseudomonas aeruginosa biofilms. Several particle formulations were attempted in order to permit the use of the smallest dose of nanoparticles while maintaining pyruvate dehydrogenase activity for an extended time length. The nanoparticles synthesized using the optimal formulation showed an average size of 266.7 ± 1.8 nm. The encapsulation efficiency of pyruvate dehydrogenase was measured at 17.9 ± 1.4%. Most importantly, the optimal formulation dispersed biofilms and exhibited enzymatic activity after being stored at 37 °C for 6 days.},
}
@article {pmid31563763,
year = {2019},
author = {Kart, D and Yabanoglu Ciftci, S and Nemutlu, E},
title = {Altered metabolomic profile of dual-species biofilm: Interactions between Proteus mirabilis and Candida albicans.},
journal = {Microbiological research},
volume = {230},
number = {},
pages = {126346},
doi = {10.1016/j.micres.2019.126346},
pmid = {31563763},
issn = {1618-0623},
abstract = {In this study, we aimed to determine the interspecies interactions between Proteus mirabilis and Candida albicans. Mono and dual-species biofilms were grown in a microtiter plate and metabolomic analysis of the biofilms was performed. The effects of togetherness of two species on the expression levels of candidal virulence genes and urease and swarming activities of P.mirabilis were investigated. The growth of C.albicans was inhibited by P.mirabilis whereas the growth and swarming activity of P.mirabilis were increased by C.albicans. The inhibition of Candida cell growth was found to be biofilm specific. The alteration was not detected in urease activity. The expressions of EFG1, HWP1 and SAP2 genes were significantly down-regulated, however, LIP1 was upregulated by P.mirabilis. In the presence of P.mirabilis carbonhydrates, amino acids, polyamine and lipid metabolisms were altered in C.albicans. Interestingly, the putrescine level was increased up to 230 fold in dual-species biofilm compared to monospecies C.albicans biofilm. To our knowledge, this is the first study to investigate the impact of each microbial pathogen on the dual microbial environment by integration of metabolomic data.},
}
@article {pmid31562986,
year = {2019},
author = {Caizán-Juanarena, L and Krug, JR and Vergeldt, FJ and Kleijn, JM and Velders, AH and Van As, H and Ter Heijne, A},
title = {3D biofilm visualization and quantification on granular bioanodes with magnetic resonance imaging.},
journal = {Water research},
volume = {167},
number = {},
pages = {115059},
doi = {10.1016/j.watres.2019.115059},
pmid = {31562986},
issn = {1879-2448},
abstract = {The use of microbial fuel cells (MFCs) for wastewater treatment fits in a circular economy context, as they can produce electricity by the removal of organic matter in the wastewater. Activated carbon (AC) granules are an attractive electrode material for bioanodes in MFCs, as they are cheap and provide electroactive bacteria with a large surface area for attachment. The characterization of biofilm growth on AC granules, however, is challenging due to their high roughness and three-dimensional structure. In this research, we show that 3D magnetic resonance imaging (MRI) can be used to visualize biofilm distribution and determine its volume on irregular-shaped single AC granules in a non-destructive way, while being combined with electrochemical and biomass analyses. Ten AC granules with electroactive biofilm (i.e. granular bioanodes) were collected at different growth stages (3 to 21 days after microbial inoculation) from a multi-anode MFC and T1-weighted 3D-MRI experiments were performed for three-dimensional biofilm visualization. With time, a more homogeneous biofilm distribution and an increased biofilm thickness could be observed in the 3D-MRI images. Biofilm volumes varied from 0.4 μL (day 4) to 2 μL (day 21) and were linearly correlated (R2 = 0.9) to the total produced electric charge and total nitrogen content of the granular bioanodes, with values of 66.4 C μL-1 and 17 μg N μL-1, respectively. In future, in situ MRI measurements could be used to monitor biofilm growth and distribution on AC granules.},
}
@article {pmid31561688,
year = {2019},
author = {Jain, AK and Misra, V and Ranjan, N and Jain, SB and Gandhi, S},
title = {Speciation, Biofilm Formation and Antifungal Susceptibility of Candida Isolates from Clinically Diagnosed Patient of UTI in a Tertiary Care Hospital.},
journal = {The Journal of the Association of Physicians of India},
volume = {67},
number = {9},
pages = {42-45},
pmid = {31561688},
issn = {0004-5772},
abstract = {Introduction: The incidence of the urinary tract infections caused by Candida species, are becoming more common. Recently, an increase in the incidence of infection caused by fungi especially non albicans candida species (NAC) has been reported. Several virulence factors like biofilm formation, toxin production and presence of adhesins contribute to its pathogenesis.<br><br>Objectives: This study was undertaken to determine species distribution, biofilm formation and in-vitro antifungal susceptibility of candida isolated in our tertiary care hospital.<br><br>Method: Eighty seven clinical isolates obtained from urine specimens were subjected to wet mount, Gram's stain and cultured on Sabouraud's Dextrose agar (SDA) medium. Conventional method for yeast identification was done. Biofilm forming ability of each isolate was detected using microtitre plate method. Antifungal susceptibility against posaconazole, amphotericin-B, fluconazole, itraconazole, ketoconazole, 5-flucytosine, voriconazole, and caspofungin was tested using Sensititre® Yeastone® (Trek diagnostic systems).<br><br>Results and Discussion: Out of 87 candida isolates, 31.03% (n=27) were C. albicans and 68.97% (n=60) were non albicans candida species (NAC). Among 60 NAC, C. kruseii 29.89% (n=26), C. glabrata 24.14% (n=21), C. tropicalis 14.94% (n=13). Among all isolates, 36.78% (n=32) were biofilm producers and biofilm positivity more among C. albicans 55.56% (n=15) as compared to NAC 28.33% (n=17) (Pvalue<0.002). The maximum positivity was observed with isolates from plastic devices (61.8%). The minimum inhibitory concentrations of all antifungal drugs against all isolates were within susceptible range except for fluconazole which was resistant to C. kruseii.<br><br>Conclusion: C. albicans remains the major isolate from urine samples and also biofilm formation as a virulence factor might have a higher significance for C. albicans than for NAC and its ability to form biofilm is intricately linked with ability of organisms to adhere, colonize and subsequently cause infection.},
}
@article {pmid31561306,
year = {2019},
author = {Yu, Z and Li, W and Tan, S},
title = {Real-time monitoring of the membrane biofouling based on spectroscopic analysis in a marine MBBR-MBR (moving bed biofilm reactor-membrane bioreactor) for saline wastewater treatment.},
journal = {Chemosphere},
volume = {235},
number = {},
pages = {1154-1161},
doi = {10.1016/j.chemosphere.2019.07.005},
pmid = {31561306},
issn = {1879-1298},
abstract = {A MBBR-MBR system has been developed with marine microorganisms enriched for saline wastewater treatment in this work, showing high COD and NH3-N removals. The behaviour of fouling-related components (EPS and SMP) has been studied as functions of operating time (40-90 days), salinity (0-30 g/L NaCl) and backflow ratio (0-300%, from MBR to MBBR). High biodegradability of the MBBR-MBR at optimal conditions can induce more biodegradation of humic acid-like (λex/λem: 350nm/430 nm) and fulvic acid-like (260nm/445 nm) molecules to soluble microbial by-product-like molecules (275nm/325 nm), reducing the membrane biofouling rate. The biodegradation process is suggested by the excitation-emission matrix (EEM) images. In the study of sudden salinity shock, results show that real-time monitoring the concentration of biofoulants is more effective (operative time extended by 60%) than monitoring the transmembrane pressure (operative time extended by 33%) to prevent membrane fouling. Due to an early warning from the real-time monitoring, the coming membrane-fouling is predictable and the operating conditions, such as backflow ratio, can be changed to minimize the biofouling rate.},
}
@article {pmid31558046,
year = {2019},
author = {Oliveira, GS and Lopes, DRG and Andre, C and Silva, CC and Baglinière, F and Vanetti, MCD},
title = {Multispecies biofilm formation by the contaminating microbiota in raw milk.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-13},
doi = {10.1080/08927014.2019.1666267},
pmid = {31558046},
issn = {1029-2454},
abstract = {Biofilms can be formed on the surfaces of dairy processing equipment and are a potential source of product contamination. This study evaluated the diversity of multispecies biofilms formed on stainless steel (SS) due to the contaminating microbiota in raw milk. Samples of raw milk were used: one was fresh milk and the other maintained in refrigerated bulk tanks for up to 48 h. The mesophilic aerobic contamination was ∼104 CFU ml-1 in fresh milk and 106 CFU ml-1 in bulk milk. SS coupons were kept immersed in the milk at 7 ±2 °C for 10 days, and every two days, the raw milk was changed for samples of the same origin collected on the current day. After incubation for 10 days, sessile cells in the biofilm reached 105 CFU cm-2 in the presence of fresh milk, and 106 CFU cm-2 in the presence of bulk milk. The genetic diversity analysis showed that Gammaproteobacteria and Bacilli predominated in the biofilms throughout the incubation of both milk samples and these biofilms showed a reduction in diversity over time. The main classes of bacteria found in these biofilms have representatives of great importance since many of them have spoilage potential.},
}
@article {pmid31557551,
year = {2019},
author = {Kurt, A and Cilingir, A and Bilmenoglu, C and Topcuoglu, N and Kulekci, G},
title = {Effect of different polishing techniques for composite resin materials on surface properties and bacterial biofilm formation.},
journal = {Journal of dentistry},
volume = {},
number = {},
pages = {103199},
doi = {10.1016/j.jdent.2019.103199},
pmid = {31557551},
issn = {1879-176X},
abstract = {OBJECTIVES: Both direct and indirect techniques are used for composite resin material (CRM) restorations. Polishing processes are needed in both techniques after intraoral adjustment. However, it is unclear as to which polishing technique should be preferred with respect to decreasing biofilm. The purpose of thisin vitro study was to evaluate the surface properties and Streptococcus mutans biofilm formation on direct and indirect CRMs after using different polishing techniques.<br><br>METHODS: Two CRMs (direct and indirect) and four polishing techniques (aluminium oxide discs, diamond polishing paste, aluminium oxide polishing paste, and silicon carbide brush) were evaluated. The specimens were prepared for taking scanning electron microscopy images (n = 2) and determining surface roughness, surface free energy, and bacterial biofilm formation (BBF) with colony-forming unit counting and confocal laser scanning microscopy assays (n = 7). The data were analysed using two-way analysis of variance with Bonferroni as a post hoc test and Pearson's correlation (p < .05).<br><br>RESULTS: The surface roughness values in the control group were higher than those in the diamond polishing paste group (p = 0.025), but the values in the aluminium oxide polishing paste and silicon carbide brush groups were comparable with those in the control group (p = 0.156 and p = 1.000, respectively). The highest surface free energy values were recorded in the silicon carbide brush group (p < 0.001), whereas there were no differences found among the other groups (p > 0.05). The highest BBF was seen in the silicon carbide brush (p < 0.001) and direct CRM (p < 0.001) groups.<br><br>CONCLUSION: BBF on the surface of direct CRMs differed from that on indirect CRMs after polishing the surface. The tested polishing techniques significantly influenced surface properties and BBF.<br><br>CLINICAL SIGNIFICANCE: In situations that require the intraoral adjustment of CRMs, polishing with a diamond polishing paste seems to be a good option to polish the surface of both direct and indirect CRMs because the diamond polishing paste results better in terms of decreasing biofilm formation and improving surface properties.},
}
@article {pmid31556843,
year = {2019},
author = {Horváthová, T and Bauchinger, U},
title = {Biofilm Improves Isopod Growth Independent of the Dietary Cellulose Content.},
journal = {Physiological and biochemical zoology : PBZ},
volume = {92},
number = {6},
pages = {531-543},
doi = {10.1086/705441},
pmid = {31556843},
issn = {1537-5293},
abstract = {Cellulose is an abundant source of carbon, accounting for more than 50% of foliage and 90% of woody tissues of plants. Despite the diversity of species that include living or dead plant tissue in their diets, the ability to digest cellulose through self-produced enzymatic machinery is considered rare in the animal kingdom. The majority of animals studied to date rely on the cellulolytic activity of symbiotic microorganisms in their digestive tract, with some evidence for a complementary action of endogenous cellulases. Terrestrial isopods have evolved a lifestyle including feeding on a lignocellulose diet. Whether isopods utilize both external and internal cellulases for digestion of a diet is still not understood. We experimentally manipulated the content of cellulose (30%, 60%, or 90%) and the amount of biofilm (small or large) in the offered food source and quantified growth and cellulolytic activity in the gut of the isopod Porcellio scaber. The presence of a visible biofilm significantly promoted isopod growth, regardless of the cellulose content in the diet. The activity of gut cellulases was not significantly affected by the amount of biofilm or the cellulose content. Our results do not support a significant contribution of either ingested or host enzymes to cellulose utilization in P. scaber. Cellulose might not represent a key nutrient for isopods and does not seem to affect the nutritional value of the diet-associated biofilm. We propose that it is the biofilm community that determines the quality of plant diet in terrestrial isopods and potentially also in other detrital plant feeders.},
}
@article {pmid31555777,
year = {2019},
author = {Lee, JK and Mereuta, L and Luchian, T and Park, Y},
title = {Antimicrobial peptide HPA3NT3-A2 effectively inhibits biofilm formation in mice infected with drug-resistant bacteria.},
journal = {Biomaterials science},
volume = {},
number = {},
pages = {},
doi = {10.1039/c9bm01051c},
pmid = {31555777},
issn = {2047-4849},
abstract = {Bacterial biofilms formed through secretion of extracellular polymeric substances (EPS) have been implicated in many serious infections and can increase antibiotic resistance by a factor of more than 1000. Here, we examined the abilities of the antimicrobial peptide HPA3NT3-A2 to inhibit and reduce biofilm formation, eliminate EPS, and suppress inflammation in mice infected with clinical isolates of drug-resistant Pseudomonas aeruginosa strains. HPA3NT3-A2 was developed from a desirable analogue peptide, HPA3NT3, derived from residues 2-20 of the Helicobacter pylori ribosomal protein L1. HPA3NT3-A2 showed stronger activity against planktonic cells (MIC: 8 μM) compared to ciprofloxacin or tobramycin (>512 μM), and a favorable minimum biofilm inhibition and elimination concentration. This peptide also neutralized LPS; decreased levels of EPS; inhibited the production of pro-inflammatory cytokines in the lung, kidney, and spleen; decreased white blood cell counts; and increased survival among infected mice.},
}
@article {pmid31553873,
year = {2019},
author = {Sommer, R and Rox, K and Wagner, S and Hauck, D and Henrikus, S and Newsad, S and Arnold, T and Ryckmans, T and Brönstrup, M and Imberty, A and Varrot, A and Hartmann, RW and Titz, A},
title = {Anti-Biofilm Agents against Pseudomonas aeruginosa: a Structure-Activity Relationship Study of C-Glycosidic LecB Inhibitors.},
journal = {Journal of medicinal chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.jmedchem.9b01120},
pmid = {31553873},
issn = {1520-4804},
abstract = {Biofilm formation is a key mechanism of antimicrobial resistance. We have recently reported two classes of orally bioavailable C-glycosidic inhibitors of the Pseudomonas aeruginosa lectin LecB with anti-biofilm activity. They proved efficient in target binding, were metabolically stable, non-toxic, selective and potent in inhibiting formation of bacterial biofilm. Here, we designed and synthesized 6 new carboxamides and 24 new sulfonamides for a detailed structure-activity-relationship for two clinically representative LecB variants. Sulfonamides generally showed higher inhibition compared to carboxamides which was rationalized based on crystal structure analyses. Substitutions at the thiophenesulfonamide increased binding through extensive contacts with a lipophilic protein patch. These metabolically stable compounds showed a further increase in potency towards the target and in biofilm inhibition assays. In general, we established the structure-activity relationship for these promising anti-biofilm agents and showed that modification of the sulfonamide residue bears future optimization potential.},
}
@article {pmid31552285,
year = {2019},
author = {Kaldhone, PR and Carlton, A and Aljahdali, N and Khajanchi, BK and Sanad, YM and Han, J and Deck, J and Ricke, SC and Foley, SL},
title = {Evaluation of Incompatibility Group I1 (IncI1) Plasmid-Containing Salmonella enterica and Assessment of the Plasmids in Bacteriocin Production and Biofilm Development.},
journal = {Frontiers in veterinary science},
volume = {6},
number = {},
pages = {298},
doi = {10.3389/fvets.2019.00298},
pmid = {31552285},
issn = {2297-1769},
abstract = {Mobile genetic elements, such as plasmids, can potentially increase the ability of bacteria to infect and persist in vertebrate host cells. IncI1 plasmids are widely distributed in Salmonella from food animal sources and associated with clinically important strains. These plasmids often encode antimicrobial resistance; however, little is known about their impact on the virulence of Salmonella strains. To assess the potential impact of the plasmids on virulence, 43 IncI1-positive Salmonella isolates from human and animal sources were subjected to whole genome sequence (WGS) analyses and evaluated for their abilities to invade and persist for 48 h in Caco-2 human intestinal epithelial cells, form biofilms and encode bacteriocins. Draft WGS data were submitted to predict the presence of virulence and antimicrobial resistance genes, plasmid replicon types present, conduct plasmid multilocus sequence typing (pMLST), and core genome MLST (cgMLST) in the isolates. Caco-2 cells were infected with Salmonella strains and incubated for both one and 48 h for the invasion and persistence assays, respectively. Additionally, Salmonella isolates and IncI1 plasmid carrying transconjugants (n = 12) generated in Escherichia coli were assessed for their ability to produce biofilms and bacteriocin inhibition of growth of other bacteria. All Salmonella isolates infected Caco-2 cells and persisted in the cells at 48 hrs. Persistent cell counts were observed to be significantly higher than invasion assay cell counts in 26% of the isolates. Among the IncI1 plasmids, there were 18 pMLST types. Nearly 35% (n = 15) of Salmonella isolates produced biofilms; however, none of the IncI1-positive transconjugants produced increased biofilms compared to the recipient. Approximately 65% (n = 28) of isolates and 67% (n = 8) of IncI1-positive transconjugants were able to inhibit growth of at least one E. coli strain; however, none inhibited the growth of strains from species other than E. coli. The study characterized IncI1 positive Salmonella isolates and provided evidence about the potential contributions of IncI1 plasmids virulence phenotypes and areas where they do not. These findings should allow for more focused efforts to assess the impact of plasmids on bacterial pathophysiology and human health.},
}
@article {pmid31552139,
year = {2019},
author = {Willett, JLE and Ji, MM and Dunny, GM},
title = {Exploiting biofilm phenotypes for functional characterization of hypothetical genes in Enterococcus faecalis.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {23},
doi = {10.1038/s41522-019-0099-0},
pmid = {31552139},
issn = {2055-5008},
abstract = {Enterococcus faecalis is a commensal organism as well as an important nosocomial pathogen, and its infections are typically linked to biofilm formation. Nearly 25% of the E. faecalis OG1RF genome encodes hypothetical genes or genes of unknown function. Elucidating their function and how these gene products influence biofilm formation is critical for understanding E. faecalis biology. To identify uncharacterized early biofilm determinants, we performed a genetic screen using an arrayed transposon (Tn) library containing ~2000 mutants in hypothetical genes/intergenic regions and identified eight uncharacterized predicted protein-coding genes required for biofilm formation. We demonstrate that OG1RF_10435 encodes a phosphatase that modulates global protein expression and arginine catabolism and propose renaming this gene bph (biofilm phosphatase). We present a workflow for combining phenotype-driven experimental and computational evaluation of hypothetical gene products in E. faecalis, which can be used to study hypothetical genes required for biofilm formation and other phenotypes of diverse bacteria.},
}
@article {pmid31552130,
year = {2019},
author = {El-Ezmerli, NF and Gregory, RL},
title = {Effect of nicotine on biofilm formation of Streptococcus mutans isolates from smoking and non-smoking subjects.},
journal = {Journal of oral microbiology},
volume = {11},
number = {1},
pages = {1662275},
doi = {10.1080/20002297.2019.1662275},
pmid = {31552130},
issn = {2000-2297},
abstract = {Objectives: To investigate effects of nicotine on biofilm formation of Streptococcus mutans isolates from oral washes of smoker and non-smoker human subjects. Materials and methods: This study was conducted using 60 S. mutans isolates with three S. mutans isolates collected from oral washes of ten smoking subjects and ten from non-smoking subjects. Biofilm was formed by culturing each S. mutans strain (10 μl) in 190 μl of TSB supplemented with 1% sucrose (TSBS) containing 0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0, and 32.0 mg/ml of nicotine for 24 h in 5% CO2 at 37°C in 96 well microtiter plates. The absorbance values of biofilm were measured at 490 nm in a microplate spectrophotometer. Results: There was a significant effect (p-value < 0.05) of nicotine concentrations and smoking on the growth of biofilm, planktonic cells, and total absorbance, for all strains of S. mutans. Isolates from smokers had significantly more biofilm at 0-16 mg/ml of nicotine compared to those from non-smokers (p-value < 0.0001). Conclusion: S. mutans smoker isolates are more affected by high nicotine concentrations than non-smoker isolates. Clinical Relevance: The use of nicotine products increases the growth of S. mutans and may place tobacco users at risk for dental decay.},
}
@article {pmid31551964,
year = {2019},
author = {Selvaraj, A and Jayasree, T and Valliammai, A and Pandian, SK},
title = {Myrtenol Attenuates MRSA Biofilm and Virulence by Suppressing sarA Expression Dynamism.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2027},
doi = {10.3389/fmicb.2019.02027},
pmid = {31551964},
issn = {1664-302X},
abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a deleterious human pathogen responsible for severe morbidity and mortality worldwide. The pathogen has attained high priority in the World Health Organization (WHO) - Multidrug-resistant (MDR) pathogens list. Emerging MDR strains of S. aureus are clinically challenging due to failure in conventional antibiotic therapy. Biofilm formation is one of the underlying mechanisms behind the antibiotic resistance. Hence, attenuating biofilm formation has become an alternative strategy to control persistent infections. The current study is probably the first that focuses on the antibiofilm and antivirulence potential of myrtenol against MRSA and its clinical isolates. Myrtenol exhibited a concentration-dependent biofilm inhibition without causing any harmful effect on cell growth and viability. Further, microscopic analysis validated the biofilm inhibitory efficacy of myrtenol against MRSA. In addition, myrtenol inhibited the synthesis of major virulence factors including slime, lipase, α-hemolysin, staphyloxanthin and autolysin. Inhibition of staphyloxanthin in turn sensitized the MRSA cells to healthy human blood and hydrogen peroxide (H2O2). Notably, myrtenol treated cells were deficient in extracellular DNA (eDNA) mediated autoaggregation as eDNA releasing autolysis was impaired by myrtenol. Biofilm disruptive activity on preformed biofilms was observed at concentrations higher than minimum biofilm inhibitory concentration (MBIC) of myrtenol. Also, the non-cytotoxic effect of myrtenol on human peripheral blood mononuclear cell (PBMC) was evidenced by trypan blue and Alamar blue assays. Transcriptional analysis unveiled the down-regulation of global regulator sarA and sarA mediated virulence genes upon myrtenol treatment, which is well correlated with results of phenotypic assays. Thus, the results of the present study revealed the sarA mediated antibiofilm and antivirulence potential of myrtenol against MRSA.},
}
@article {pmid31551940,
year = {2019},
author = {Bottagisio, M and Soggiu, A and Piras, C and Bidossi, A and Greco, V and Pieroni, L and Bonizzi, L and Roncada, P and Lovati, AB},
title = {Proteomic Analysis Reveals a Biofilm-Like Behavior of Planktonic Aggregates of Staphylococcus epidermidis Grown Under Environmental Pressure/Stress.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1909},
doi = {10.3389/fmicb.2019.01909},
pmid = {31551940},
issn = {1664-302X},
abstract = {Prosthetic joint replacement failure has a huge impact on quality of life and hospitalization costs. A leading cause of prosthetic joint infection is bacteria-forming biofilm on the surface of orthopedic devices. Staphylococcus epidermidis is an emergent, low-virulence pathogen implicated in chronic infections, barely indistinguishable from aseptic loosening when embedded in a mature matrix. The literature on the behavior of quiescent S. epidermidis in mature biofilms is scarce. To fill this gap, we performed comparative analysis of the whole proteomic profiles of two methicillin-resistant S. epidermidis strains growing in planktonic and in sessile form to investigate the molecular mechanisms underlying biofilm stability. After 72-h culture of biofilm-forming S. epidermidis, overexpression of proteins involved in the synthesis of nucleoside triphosphate and polysaccharides was observed, whereas planktonic bacteria expressed proteins linked to stress and anaerobic growth. Cytological analysis was performed to determine why planktonic bacteria unexpectedly expressed proteins typical of sessile culture. Images evidenced that prolonged culture under vigorous agitation can create a stressful growing environment that triggers microorganism aggregation in a biofilm-like matrix as a mechanism to survive harsh conditions. The choice of a unique late time point provided an important clue for future investigations into the biofilm-like behavior of planktonic cells. Our preliminary results may inform comparative proteomic strategies in the study of mature bacterial biofilm. Finally, there is an increasing number of studies on the aggregation of free-floating bacteria embedded in an extracellular matrix, prompting the need to gain further insight into this mode of bacterial growth.},
}
@article {pmid31551455,
year = {2019},
author = {Valliammai, A and Sethupathy, S and Priya, A and Selvaraj, A and Bhaskar, JP and Krishnan, V and Pandian, SK},
title = {5-Dodecanolide interferes with biofilm formation and reduces the virulence of Methicillin-resistant Staphylococcus aureus (MRSA) through up regulation of agr system.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {13744},
doi = {10.1038/s41598-019-50207-y},
pmid = {31551455},
issn = {2045-2322},
abstract = {Methicillin resistant Staphylococcus aureus (MRSA) is a predominant human pathogen with high morbidity that is listed in the WHO high priority pathogen list. Being a primary cause of persistent human infections, biofilm forming ability of S. aureus plays a pivotal role in the development of antibiotic resistance. Hence, targeting biofilm is an alternative strategy to fight bacterial infections. The present study for the first time demonstrates the non-antibacterial biofilm inhibitory efficacy of 5-Dodecanolide (DD) against ATCC strain and clinical isolates of S. aureus. In addition, DD is able to inhibit adherence of MRSA on human plasma coated Titanium surface. Further, treatment with DD significantly reduced the eDNA synthesis, autoaggregation, staphyloxanthin biosynthesis and ring biofilm formation. Reduction in staphyloxanthin in turn increased the susceptibility of MRSA to healthy human blood and H2O2 exposure. Quantitative PCR analysis revealed the induced expression of agrA and agrC upon DD treatment. This resulted down regulation of genes involved in biofilm formation such as fnbA and fnbB and up regulation of RNAIII, hld, psmα and genes involved in biofilm matrix degradation such as aur and nuc. Inefficacy of DD on the biofilm formation of agr mutant further validated the agr mediated antibiofilm potential of DD. Notably, DD was efficient in reducing the in vivo colonization of MRSA in Caenorhabditis elegans. Results of gene expression studies and physiological assays unveiled the agr mediated antibiofilm efficacy of DD.},
}
@article {pmid31551152,
year = {2019},
author = {Qi, M and Li, X and Sun, X and Li, C and Tay, FR and Weir, MD and Dong, B and Zhou, Y and Wang, L and Xu, HHK},
title = {Novel nanotechnology and near-infrared photodynamic therapy to kill periodontitis-related biofilm pathogens and protect the periodontium.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.dental.2019.08.115},
pmid = {31551152},
issn = {1879-0097},
abstract = {OBJECTIVE: Periodontal tissue destruction and tooth loss are increasingly a worldwide problem as the population ages. Periodontitis is caused by bacterial infection and biofilm plaque buildup. Therefore, the objectives of this study were to: (1) develop a near-infrared light (NIR)-triggered core-shell nanostructure of upconversion nanoparticles and TiO2 (UCNPs@TiO2), and (2) investigate its inhibitory effects via antibacterial photodynamic therapy (aPDT) against periodontitis-related pathogens.<br><br>METHODS: The core β-NaYF4:Yb3+,Tm3+ were synthesized via thermal decomposition and further modified with the TiO2 shell via a hydrothermal method. The core-shell structure and the upconversion fluorescence-induced aPDT treatment via 980nm laser were studied. Three periodontitis-related pathogens Streptococcus sanguinis (S. sanguinis), Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) were investigated. The killing activity against planktonic bacteria was detected by a time-kill assay. Single species 4-day biofilms on dentin were tested by live/dead staining, colony-forming units (CFU), and metabolic activity.<br><br>RESULTS: The hexagonal shaped UCNPs@TiO2 had an average diameter of 39.7nm. UCNPs@TiO2 nanoparticles had positively charged (+12.4mV) surface and were biocompatible and non-cytotoxic. Under the excitation of NIR light (980nm), the core NaYF4:Yb3+,Tm3+ UCNPs could emit intense ultraviolet (UV) light, which further triggered the aPDT function of the shell TiO2 via energy transfer, thereby realizing the remarkable antibacterial effects against planktons and biofilms of periodontitis-associated pathogens. NIR-triggered UCNPs@TiO2 achieved much greater reduction in biofilms than control (p<0.05). Biofilm CFU was reduced by 3-4 orders of magnitude via NIR-triggered aPDT, which is significantly greater than that of negative control and commercial aPDT control groups. The killing efficacy of UCNPs@TiO2-based aPDT against the three species was ranked to be: S. sanguinis<F. nucleatum=P. gingivalis. Metabolic activities of biofilms were also greatly reduced via NIR-triggered aPDT (p<0.05).<br><br>SIGNIFICANCE: Upconversion fluorescence-based aPDT achieved strong inhibiting effects against all three species of periodontitis-related pathogens. This novel nanotechnology demonstrated a high promise to inhibit periodontitis, with exciting potential to combat other oral infectious diseases such as deep endodontic infections.},
}
@article {pmid31550929,
year = {2019},
author = {de Freitas, LM and Lorenzón, EN and Cilli, EM and de Oliveira, KT and Fontana, CR and Mang, TS},
title = {Photodynamic and peptide-based strategy to inhibit Gram-positive bacterial biofilm formation.},
journal = {Biofouling},
volume = {35},
number = {7},
pages = {742-757},
doi = {10.1080/08927014.2019.1655548},
pmid = {31550929},
issn = {1029-2454},
abstract = {The self-produced extracellular polymeric matrix of biofilms renders them difficult to eliminate once they are established. This makes the inhibition of biofilm formation key to successful treatment of biofilm infection. Antimicrobial photodynamic therapy (aPDT) and antimicrobial peptides offer a new approach as antibiofilm strategies. In this study sub-lethal doses of aPDT (with chlorin-e6 (Ce6-PDT) or methylene blue (MB-PDT)) and the peptides AU (aurein 1.2 monomer) or (AU)2K (aurein 1.2 C-terminal dimer) were combined to evaluate their ability to prevent biofilm development by Enterococcus faecalis. Biofilm formation was assessed by resazurin reduction, confocal microscopy, and infrared spectroscopy. All treatments successfully prevented biofilm development. The (AU)2K dimer had a stronger effect, both alone and combined with aPDT, while the monomer AU had significant activity when combined with Ce6-PDT. Additionally, it is shown that the peptides bind to the lipoteichoic acid of the E. faecalis cell wall, pointing to a possible key mechanism of biofilm inhibition.},
}
@article {pmid31550928,
year = {2019},
author = {Werner, BG and Wu, JY and Goddard, JM},
title = {Antimicrobial and antifouling polymeric coating mitigates persistence of Pseudomonas aeruginosa biofilm.},
journal = {Biofouling},
volume = {35},
number = {7},
pages = {785-795},
doi = {10.1080/08927014.2019.1660774},
pmid = {31550928},
issn = {1029-2454},
abstract = {Food wasted due to food spoilage remains a global challenge to the environmental sustainability and security of food supply. In food manufacturing, post-processing contamination of food can occur due to persistent bacterial biofilms, which can be resistant to conventional cleaning and sanitization. The objective was to characterize the efficacy of a polymeric coating in reducing Pseudomonas aeruginosa biofilm establishment and facilitating its removal. Viable cell density of a 48 h biofilm was reduced by 2.10 log cfu cm-2 on the coated surface, compared to native polypropylene. Confocal laser scanning and electron microscopy indicated reductions in mature biofilm viability and thickness on the coated material. The antifouling coating improved cleanability, with ∼2.5 log cfu cm-2 of viable cells remaining after 105 min cleaning by water at 65 °C, compared to 4.5 log cfu cm-2 remaining on native polypropylene. Such coatings may reduce the persistence of biofilms in food processing environments, in support of reducing food spoilage and waste.},
}
@article {pmid31550124,
year = {2019},
author = {Hoque, J and Ghosh, S and Paramanandham, K and Haldar, J},
title = {Charge-Switchable Polymeric Coating Kills Bacteria and Prevents Biofilm Formation In vivo.},
journal = {ACS applied materials &amp; interfaces},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsami.9b11453},
pmid = {31550124},
issn = {1944-8252},
abstract = {Preventing bacterial biofilm formation on medical devices and implants in vivo still remains a daunting task. Current antibacterial coatings to combat implant-associated infections are generally composed of toxic metals or non-degradable polymers and involve multistep surface modifications. Here we present a charge-switchable antibacterial and antibiofilm coating based on water-insoluble cationic hydrophobic polymers that are soluble in organic solvents and can be non-covalently coated onto different surfaces. Towards this, a library of quaternary polyethylenimine (QPEI) polymers with amide or ester group in their pendant alkyl chain was developed. These QPEIs are shown to hydrolyze from active cationic to non-toxic zwitterionic polymers under acidic or enzymatic conditions. Notably polymers with both zwitterionic and cationic groups, obtained upon incomplete hydrolysis of QPEIs, are shown to retain their antibacterial activity with much lower toxicity towards mammalian cells. Furthermore the zwitterionic polymer, fully hydrolyzed product of the QPEIs, is shown to be non-toxic to mammalian cells in vitro as well as in vivo. The QPEIs-coated surfaces are shown to kill bacteria and prevent formation of biofilm. In an in vivo mice model, the QPEIs-coated medical grade catheter is shown to reduce methicillin-resistant Staphylococcus aureus (MRSA) contamination both on the catheter surface and in the adjacent tissues (99.99% reduction compared to non-coated catheter). Additionally, biofilm formation is inhibited on the catheter surface with negligible inflammation in the adjacent tissue. The above results thus highlight the importance of these polymers to be used as effective antibacterial coatings in biomedical applications.},
}
@article {pmid31548684,
year = {2019},
author = {Kowalski, CH and Kerkaert, JD and Liu, KW and Bond, MC and Hartmann, R and Nadell, CD and Stajich, JE and Cramer, RA},
title = {Fungal biofilm morphology impacts hypoxia fitness and disease progression.},
journal = {Nature microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41564-019-0558-7},
pmid = {31548684},
issn = {2058-5276},
support = {5T32 GM 8704-20//U.S. Department of Health &amp; Human Services | NIH | National Institute of General Medical Sciences (NIGMS)/ ; P20-GM113132//U.S. Department of Health &amp; Human Services | NIH | National Institute of General Medical Sciences (NIGMS)/ ; F31AI138354//U.S. Department of Health &amp; Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; R01AI130128//U.S. Department of Health &amp; Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; 2R01AI081838//U.S. Department of Health &amp; Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; MCB 1817342//NSF | BIO | Division of Molecular and Cellular Biosciences (MCB)/ ; Burke Award//Dartmouth College (Dartmouth)/ ; STANTO15RO//Cystic Fibrosis Foundation (CF Foundation)/ ; DBI-1429826//NSF | BIO | Division of Biological Infrastructure (DBI)/ ; S10-OD016290//U.S. Department of Health &amp; Human Services | NIH | NIH Office of the Director (OD)/ ; },
abstract = {Microbial populations form intricate macroscopic colonies with diverse morphologies whose functions remain to be fully understood. Despite fungal colonies isolated from environmental and clinical samples revealing abundant intraspecies morphological diversity, it is unclear how this diversity affects fungal fitness and disease progression. Here we observe a notable effect of oxygen tension on the macroscopic and biofilm morphotypes of the human fungal pathogen Aspergillus fumigatus. A hypoxia-typic morphotype is generated through the expression of a subtelomeric gene cluster containing genes that alter the hyphal surface and perturb interhyphal interactions to disrupt in vivo biofilm and infection site morphologies. Consequently, this morphotype leads to increased host inflammation, rapid disease progression and mortality in a murine model of invasive aspergillosis. Taken together, these data suggest that filamentous fungal biofilm morphology affects fungal-host interactions and should be taken into consideration when assessing virulence and host disease progression of an isolated strain.},
}
@article {pmid31548510,
year = {2019},
author = {Lin, Q and Sun, H and Yao, K and Cai, J and Ren, Y and Chi, Y},
title = {The Prevalence, Antibiotic Resistance and Biofilm Formation of Staphylococcus aureus in Bulk Ready-To-Eat Foods.},
journal = {Biomolecules},
volume = {9},
number = {10},
pages = {},
doi = {10.3390/biom9100524},
pmid = {31548510},
issn = {2218-273X},
abstract = {The prevalence of Staphylococcus aureus in 2160 bulk ready-to-eat foods from the Sichuan province of China during 2013-2016 was investigated. The antibiotic resistance and the associated genes, as well as biofilm formation capacity of the S. aureus isolates were measured. Furthermore, the relationship between the antibiotic resistance and the resistant genes was discussed. It was found that 54 S. aureus isolates were recovered, and their prevalence in meat products, dairy, fruit and vegetables, and desserts were 31 (2.6%), six (3.0%), nine (2.2%) and eight (2.3%), respectively. Most strains (52/54) were resistant to at least one of the antibiotics, and 21 isolates were identified as multidrug-resistant (MDR) S. aureus. Three isolates were found to be methicillin-resistant S. aureus. Penicillin, erythromycin, clindamycin, tetracycline and inducible clindamycin resistance were determined as the predominant antibiotics, and the isolates with the phenotypic resistance on these five antibiotics were all determined positive for the resistant gene associated. In total, 33 of 54 S. aureus isolates showed biofilm formation capacity, including two strong biofilm producers, one moderate and 30 weak ones. Two S. aureus isolates with strong biofilm formation abilities showed multi-drug resistance, and one moderate biofilm producer was resistant to two categories of antibiotics.},
}
@article {pmid31548325,
year = {2019},
author = {Ghimire, N and Pettygrove, BA and Pallister, KB and Stangeland, J and Stanhope, S and Klapper, I and Voyich, JM and Stewart, PS},
title = {Direct Microscopic Observation of Human Neutrophil-Staphylococcus aureus Interaction In Vitro Suggests a Potential Mechanism for Initiation of Biofilm Infection on an Implanted Medical Device.},
journal = {Infection and immunity},
volume = {},
number = {},
pages = {},
doi = {10.1128/IAI.00745-19},
pmid = {31548325},
issn = {1098-5522},
abstract = {The ability of human neutrophils to clear newly attached Staphylococcus aureus bacteria from a serum-coated glass surface was examined in vitro using time-lapse confocal scanning laser microscopy. Quantitative image analysis was used to measure the temporal change in bacterial biomass, neutrophil motility, and fraction of the surface area policed by neutrophils. In control experiments in which the surface was inoculated with bacteria but no neutrophils were added, prolific bacterial growth was observed. Neutrophils were able to control bacterial growth but only consistently when the neutrophil:bacteria number ratio exceeded approximately one. When pre-attached bacteria were given a head start and allowed to grow for three hours prior to neutrophil addition, neutrophils were unable to maintain control of the nascent biofilm. In these head start experiments, aggregates of bacterial biofilm with areas of 50 μm2 or larger formed and the growth of such aggregates continued even when multiple neutrophils attacked a cluster. These results suggest a model for the initiation of a biofilm infection in which a delay in neutrophil recruitment to an abiotic surface allows surface-attached bacteria time to grow and form aggregates that become protected from neutrophil clearance. Results from a computational model of the neutrophil-biofilm surface contest supported this conceptual model and highlighted the stochastic nature of the interaction. Additionally, we observed that both neutrophil motility and clearance of bacteria were impaired when oxygen tension was reduced to 0% or 2% O2SIGNIFICANCE Bacteria or yeast that form biofilms on implanted medical devices such as artificial hip joints cause troublesome infections. These device-associated infections are persistent because biofilm-embedded microorganisms are protected from antibiotics and host defenses. Three decades of research in antimicrobial coatings and non-stick surfaces have not yet solved the biofilm infection problem. Here we show in a model system that neutrophils can effectively clear contaminating Staphylococcus aureus bacteria from an abiotic surface, but they must be delivered quickly and in sufficient numbers. If neutrophil recruitment is delayed, undiscovered bacteria grow and form aggregates that evade engulfment and killing by white blood cells. This work opens a pathway to preventing infections on implanted medical devices by transiently boosting innate immune defenses.},
}
@article {pmid31547513,
year = {2019},
author = {Erdmann, J and Thöming, JG and Pohl, S and Pich, A and Lenz, C and Häussler, S},
title = {The Core Proteome of Biofilm-Grown Clinical Pseudomonas aeruginosa Isolates.},
journal = {Cells},
volume = {8},
number = {10},
pages = {},
doi = {10.3390/cells8101129},
pmid = {31547513},
issn = {2073-4409},
support = {724290/ERC_/European Research Council/International ; },
abstract = {Comparative genomics has greatly facilitated the identification of shared as well as unique features among individual cells or tissues, and thus offers the potential to find disease markers. While proteomics is recognized for its potential to generate quantitative maps of protein expression, comparative proteomics in bacteria has been largely restricted to the comparison of single cell lines or mutant strains. In this study, we used a data independent acquisition (DIA) technique, which enables global protein quantification of large sample cohorts, to record the proteome profiles of overall 27 whole genome sequenced and transcriptionally profiled clinical isolates of the opportunistic pathogen Pseudomonas aeruginosa. Analysis of the proteome profiles across the 27 clinical isolates grown under planktonic and biofilm growth conditions led to the identification of a core biofilm-associated protein profile. Furthermore, we found that protein-to-mRNA ratios between different P. aeruginosa strains are well correlated, indicating conserved patterns of post-transcriptional regulation. Uncovering core regulatory pathways, which drive biofilm formation and associated antibiotic tolerance in bacterial pathogens, promise to give clues to interactions between bacterial species and their environment and could provide useful targets for new clinical interventions to combat biofilm-associated infections.},
}
@article {pmid31547458,
year = {2019},
author = {Zhang, XY and Sun, K and Abulimiti, A and Xu, PP and Li, ZY},
title = {Microfluidic System for Observation of Bacterial Culture and Effects on Biofilm Formation at Microscale.},
journal = {Micromachines},
volume = {10},
number = {9},
pages = {},
doi = {10.3390/mi10090606},
pmid = {31547458},
issn = {2072-666X},
support = {61674046//National Natural Science Foundation of China/ ; 2017TS04//State Key Laboratory of Urban Water Resource and Environment (Harbin Institute of Technology)/ ; },
abstract = {Biofilms exist in the natural world and applied to many industries. However, due to the variety of characteristics caused by their complex components, biofilms can also lead to membrane fouling and recurrent infections which pose threats to human health. So, to make the best use of their advantages and avoid their disadvantages, knowing the best time and methods for improving or preventing biofilm formation is important. In situ observation without fluorescence labeling in microscale and according to a time scale is useful to research biofilm and confine its formation. In this study, we developed a microfluidic system for real-time observation of bacteria culture and biofilms development at microscale. We cultured E. coli ATCC 25922 on a chip at continuous flow of the velocity, which could promote bacterial formation. Biofilms formation under the condition of adding amoxicillin at different times is also discussed. In addition, the mixed strains from sludge were also cultured on chip, and possible factors in biofilm formation are discussed. Our results show that a microfluidic device could culture microorganisms in continuous flow and accelerate them to adhere to the surface, thereby promoting biofilm formation. Overall, this platform is a useful tool in research on initial biofilm formation, which can contribute to preventing biofouling and infections.},
}
@article {pmid31547282,
year = {2019},
author = {Kerekes, EB and Vidács, A and Takó, M and Petkovits, T and Vágvölgyi, C and Horváth, G and Balázs, VL and Krisch, J},
title = {Anti-Biofilm Effect of Selected Essential Oils and Main Components on Mono- and Polymicrobic Bacterial Cultures.},
journal = {Microorganisms},
volume = {7},
number = {9},
pages = {},
doi = {10.3390/microorganisms7090345},
pmid = {31547282},
issn = {2076-2607},
support = {4330//University of Szeged Open Access Fund/ ; },
abstract = {Biofilms are surface-associated microbial communities resistant to sanitizers and antimicrobials. Various interactions that can contribute to increased resistance occur between the populations in biofilms. These relationships are the focus of a range of studies dealing with biofilm-associated infections and food spoilage. The present study investigated the effects of cinnamon (Cinnamomum zeylanicum), marjoram (Origanum majorana), and thyme (Thymus vulgaris) essential oils (EOs) and their main components, i.e., trans-cinnamaldehyde, terpinen-4-ol, and thymol, respectively, on single- and dual-species biofilms of Escherichia coli, Listeria monocytogenes, Pseudomonas putida, and Staphylococcus aureus. In dual-species biofilms, L. monocytogenes was paired with each of the other three bacteria. Minimum inhibitory concentration (MIC) values for the individual bacteria ranged between 0.25 and 20 mg/mL, and trans-cinnamaldehyde and cinnamon showed the highest growth inhibitory effect. Single-species biofilms of L. monocytogenes, P. putida, and S. aureus were inhibited by the tested EOs and their components at sub-lethal concentrations. Scanning electron microscopy images showed that the three-dimensional structure of mature biofilms embedded in the exopolysaccharide matrix disappeared or was limited to micro-colonies with a simplified structure. In most dual-species biofilms, to eliminate living cells from the matrix, concentrations exceeding the MIC determined for individual bacteria were required.},
}
@article {pmid31546523,
year = {2019},
author = {Das, D and Bhattacharjee, H and Gogoi, K and Das, JK and Misra, P and Dhir, P and Deka, A},
title = {Intraocular lens biofilm formation supported by scanning electron microscopy imaging.},
journal = {Indian journal of ophthalmology},
volume = {67},
number = {10},
pages = {1708-1709},
doi = {10.4103/ijo.IJO_467_19},
pmid = {31546523},
issn = {1998-3689},
}
@article {pmid31546354,
year = {2019},
author = {Eduok, U and Ohaeri, E and Szpunar, J},
title = {Accelerated corrosion of pipeline steel in the presence of Desulfovibrio desulfuricans biofilm due to carbon source deprivation in CO2 saturated medium.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {105},
number = {},
pages = {110095},
doi = {10.1016/j.msec.2019.110095},
pmid = {31546354},
issn = {1873-0191},
abstract = {The chemistry of bacterial biofilms as well as the nutritional composition of culture environments may differ at any time within a growth process, especially for SRB consortia within oil wells with limited carbon sources. In the oilfield, the presence of SRB biofilms on surfaces of steel substrates leads to microbiologically influenced corrosion and compromised material integrity. In this work, the survival of SRB cells and their impact on the pipeline steel corrosion within simulated CO2-saturated oilfield-produced water with different concentrations of organic carbon source have been investigated. Cell counts reduced with the level of carbon source reduction (CSR) after incubation but more sessile cells survived at 80% CSR (moderate carbon starvation) compared to 100% CSR (extreme carbon starvation). The energy needed for cellular survival as well as biological support toward MIC could have been harnessed by a combination of extracellular Feo oxidation and intracellular sulfate reduction even after carbon source starvation. Severe anodic steel dissolution was observed at the end of the culture period within the simulated CO2-saturated oilfield-produced water, and this is attributed to SRB-led MIC and CO2 corrosion. Pipeline steel corroded more when cultured within 80% CSR compared to the medium with both lactate and citrate. Steel substrate corroded less with 100% CSR due to severely weakened SRB biofilms from nutrient deprivation.},
}
@article {pmid31546042,
year = {2019},
author = {Sales, LS and Guimarães, GN and Wijesinghe, GK and Silva Moreira, KM and Joia, F and Stipp, RN and Azevedo Rodrigues, LK and Nobre-Dos-Santos, M and Steiner-Oliveira, C},
title = {Addition of hydrogen peroxide to methylene blue conjugated to β-cyclodextrin in photodynamic antimicrobial chemotherapy in S. mutans biofilm.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.09.004},
pmid = {31546042},
issn = {1873-1597},
abstract = {OBJECTIVE: This study evaluated the effect of hydrogen peroxide addition on β-cyclodextrin-conjugated methylene blue in photodynamic antimicrobial chemotherapy (PACT) inS. mutans biofilm model using laser or light emitting diode (LED) (λ = 660 nm).<br><br>METHODS: A preliminary assay was performed to evaluate the cytotoxicity of hydrogen peroxide in oral fibroblasts by the colorimetric method (MTT). Afterwards, groups were divided into (n = 3, in triplicate): C (negative control), CX - chlorhexidine 0.2% (positive control), P (methylene blue/β-cyclodextrin), H (Hydrogen Peroxide at 40 µM), PH, L (Laser), LP, LH (Laser+Hydrogen Peroxide), LPH, LED, LEDP, LEDH, and LEDPH. The biofilm was formed in 24 h with BHI + 1% sucrose (w/v). Light irradiations were conducted with laser, 9 J, 323 J/cm2, 113 s or with LED, 8.1 J, 8.1 J/cm2 for 90 s. Microbial reduction was evaluated by counting the viable microorganisms of the biofilm after the respective treatments, in a selective culture medium, and laser confocal microscopy evaluation.<br><br>RESULTS: LP, LH, LPH, LEDP, LEDH, and LEDPH groups statistically reduced the counts ofS. mutans compared with the C group and the log reductions were of 1.87, 1.94, 2.19, 0.91, 0.92, and 1.33, respectively; the addition of hydrogen peroxide did not potentiate the microbial reductions (LPH and LEDPH) compared with the LP and LEDP groups.<br><br>CONCLUSION: The association of hydrogen peroxide with the conjugated β-cyclodextrin nanoparticle as photosensitizer did not result in an enhanced effect of PACT; hydrogen peroxide behaved as a photosensitizer, since it reduced the number ofS. mutans when associated with laser light.},
}
@article {pmid31546040,
year = {2019},
author = {Ram, MK and Naveen Kumar, BT and Poojary, SR and Abhiman, PB and Patil, P and Ramesh, KS and Shankar, KM},
title = {Evaluation of biofilm of Vibrio anguillarum for oral vaccination of Asian seabass, Lates calcarifer (BLOCH, 1790).},
journal = {Fish &amp; shellfish immunology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.fsi.2019.09.053},
pmid = {31546040},
issn = {1095-9947},
abstract = {The present study evaluated the biofilm (BF) of Vibrio anguillarum for oral vaccination of Asian seabass, Lates calcarifer. An 80-day experiment was carried out in circular fiber-reinforced plastic (FRP) tanks using free cell (FC) and BF of Vibrio anguillarum with triplicate in each. Heat-inactivated FC and BF cells at 107, 1010 and 1013 CFU/g fish/d were fed to fish for 20 days, agglutination antibody titer estimated at each 10 days interval up to 60-day post vaccination. As compared to FC and control there was a significant increase in agglutinating antibody titer in the biofilm vaccinated fishes. Among the 3 doses, BF at 1010 cfu/g fish/d was considered the ideal dose for vaccination. Relative percentage survival (RPS) was higher in biofilm vaccinated fish (85.4%) compared to that with free cells (27.0%). The study demonstrated the better performance of V. anguillarum biofilm oral vaccine compared that with free cell vaccine in L. calcarifer. The study further supports better performance of biofilm vaccine model with one more bacterial pathogen in a high carnivore fish.},
}
@article {pmid31546000,
year = {2019},
author = {Campos-Silva, R and Roberta, BF and Silva, TD and Macedo, AJ},
title = {Alternative method in Galleria mellonella larvae to study biofilm infection and treatment.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103756},
doi = {10.1016/j.micpath.2019.103756},
pmid = {31546000},
issn = {1096-1208},
abstract = {In vivo studies are crucial decision-maker step in order to translate in vitro data to an applied therapy. Considering this we describe a simple method that analyzes and quantifies biofilm formation inside the Galleria mellonella larvae. Toothbrush bristles were employed as an abiotic surface to mimic a medical device. A standardized inoculum of Staphylococcus aureus was systemically injected in the larvae together with the insertion of a bristle in the last proleg pair. After incubation adhered cells were detached from bristles and quantified by colony-forming units (CFU) counting using staphylococci-selective medium. About 3 × 106 CFU of S. aureus were recovered from bristles and scanning electron microscopy images confirmed biofilm formation. Control group did not show adherent bacteria, as demonstrated by absence of CFU counting and SEM images, indicating that the insertion procedure is free of bacterial contamination. We present a feasible method to evaluate bacterial biofilm formation in vivo that in the near future can be used to evaluate antibiofilm compounds.},
}
@article {pmid31543874,
year = {2019},
author = {De Carolis, E and Soldini, S and La Rosa, M and Nucci, F and Posteraro, B and Sanguinetti, M},
title = {BIOF-HILO Assay: A New MALDI-TOF Mass Spectrometry Based Method for Discriminating Between High- and Low-Biofilm-Producing Candida parapsilosis Isolates.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2046},
doi = {10.3389/fmicb.2019.02046},
pmid = {31543874},
issn = {1664-302X},
abstract = {Candida parapsilosis is the most frequent cause of catheter-related candidemia among non-Candida albicans species. This may be related to intrinsic capabilities as adhering and forming a biofilm on abiotic surfaces such as on medical devices. As previously demonstrated, patients infected with high biofilm-producing C. parapsilosis isolates had a greater mortality risk compared to patients infected with low biofilm-producing C. parapsilosis isolates. We developed the BIOF-HILO assay, a MALDI-TOF mass spectrometry (MS)-based assay, which compares mass spectra obtained from attached and suspended isolate cells during the early (i.e., 3-h) adhesion phase of in vitro biofilm formation. The composite correlation index (CCI) analysis was used to discriminate between mass spectra differences of the two cell types, classifying all 50 C. parapsilosis clinical isolates, included in the study, after only 3-h of testing, in high or low biofilm producers. All high (n = 25) or low (n = 25) biofilm producers had, according to CCI mass spectra comparison values, higher or lower than one CCI ratios, which were obtained by dividing the CCIsuspended cells by the CCIattached cells. In conclusion, the BIOF-HILO assay allows a rapid categorization of C. parapsilosis clinical isolates in high or low biofilm producers. This information, if timely provided to physicians, may improve treatment outcomes in patients with C. parapsilosis candidemia.},
}
@article {pmid31543873,
year = {2019},
author = {Alviz-Gazitua, P and Fuentes-Alburquenque, S and Rojas, LA and Turner, RJ and Guiliani, N and Seeger, M},
title = {Corrigendum: The Response of Cupriavidus metallidurans CH34 to Cadmium Involves Inhibition of the Initiation of Biofilm Formation, Decrease in Intracellular c-di-GMP Levels, and a Novel Metal Regulated Phosphodiesterase.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2014},
doi = {10.3389/fmicb.2019.02014},
pmid = {31543873},
issn = {1664-302X},
abstract = {[This corrects the article DOI: 10.3389/fmicb.2019.01499.].},
}
@article {pmid31543653,
year = {2019},
author = {Kitti, T and Seng, R and Thummeepak, R and Boonlao, C and Jindayok, T and Sitthisak, S},
title = {Biofilm Formation of Methicillin-resistant Coagulase-Negative Staphylococci Isolated from Clinical Samples in Northern Thailand.},
journal = {Journal of global infectious diseases},
volume = {11},
number = {3},
pages = {112-117},
doi = {10.4103/jgid.jgid_118_18},
pmid = {31543653},
issn = {0974-777X},
abstract = {Background: Methicillin-resistant coagulase-negative staphylococci (MR-CoNS) are multidrug-resistant bacteria that are difficult to treat because of their ability to form biofilms.<br><br>Objectives: In the present study, we evaluated the antibiotic-resistant phenotypes, biofilm-forming ability, and biofilm associated genes of 55 clinical MR-CoNS isolates obtained from two hospitals in Thailand.<br><br>Materials and Methods: MALDI-TOF-MS and tuf gene sequencing were performed to determine the species of all isolates. Biofilm production was determined using Congo red agar (CRA) and the microtiter plate (MTP) assay. Biofilm-associated genes were characterized using polymerase chain reaction (PCR).<br><br>Results: Among the 55 MR-CoNS isolates, five species were identified as Staphylococcus haemolyticus (34.5%), Staphylococcus epidermidis (32.7%), Staphylococcus capitis (18.2%), Staphylococcus cohnii (9.1%), and Staphylococcus hominis (5.5%). The antimicrobial susceptibility pattern of MR-CoNS isolates indicated high resistance to cefoxitin (100%), penicillin (98.2%), erythromycin (96.4%), ciprofloxacin (67.3%), sulfamethoxazole/trimethoprim (67.3%), gentamicin (67.3%), and clindamycin (63.6%). All the isolates were susceptible to vancomycin and linezolid. The biofilm production was detected in 87.3% isolates through the CRA method and in 38.1% isolates through the MTP assay. The prevalence rates of icaAD, bap, fnbA, and cna were 18.2%, 12.7%, 47.3%, and 27.3%, respectively. There were significant differences in the presence of these biofilm-associated genes among the MR-CoNS isolates. Moreover, quantitative biofilm formation was significantly different among MR-CoNS species.<br><br>Conclusion: The present study revealed that biofilm-associated genes are important for biofilm biomass in MR-CoNS isolates, and the findings of this study are essential for finding new strategies to control biofilm formation and prevent the spread of MR-CoNS infectious diseases.},
}
@article {pmid31542601,
year = {2019},
author = {Mitchell, K and Lima, AT and Van Cappellen, P},
title = {Selenium in buoyant marine debris biofilm.},
journal = {Marine pollution bulletin},
volume = {149},
number = {},
pages = {110562},
doi = {10.1016/j.marpolbul.2019.110562},
pmid = {31542601},
issn = {1879-3363},
abstract = {Marine debris is widespread in all the world's oceans. Currently little is understood about how marine debris affects the chemistry of the surface oceans, particularly trace elements that can adsorb to the surface of marine debris, especially plastic debris, or be taken up by biofilms and algae growing on the surface of marine debris. Selenium (Se) is a micronutrient that is essential to all living organisms. Average seawater Se concentrations in the modern ocean are <1 nM. Here we measure the concentration of Se in surface water and one deep water sample and the concentration of Se found in algae/biofilms growing on the surface of macro-debris collected in October of 2012. Concentrations of Se in biofilm varied more according to the type of biofilm rather than the type of plastic. However, further Se measurements are needed for more conclusive results.},
}
@article {pmid31542551,
year = {2019},
author = {Acevedo Alonso, V and Lackner, S},
title = {Membrane Aerated Biofilm Reactors - How longitudinal gradients influence nitrogen removal - A conceptual study.},
journal = {Water research},
volume = {166},
number = {},
pages = {115060},
doi = {10.1016/j.watres.2019.115060},
pmid = {31542551},
issn = {1879-2448},
abstract = {Membrane-aerated biofilm reactors are becoming more important for nitrogen removal in the wastewater sector. One-dimensional (1D) models are widely used to study the performance of such systems; however, 1D models are not able to simulate the longitudinal gradients that exist in the reactor. Although there is experimental evidence that points to the existence of longitudinal gradients simple modeling approaches that consider these gradients are not yet developed. This study proposes a novel multi-compartment model that simulates the longitudinal substrate and oxygen gradients. It assesses the effects of temperature, biofilm thickness, number of compartments, and flow configuration (liquid and gas phase) on the modeling results. Additionally, it compares the capabilities of a traditional 1D model with those of the novel multi-compartment model. Our results show that a classical 1D model predicts a lower total dissolved nitrogen concentration (TDN) in the effluent in contrast to the predictions of the multi-compartment model. In the worst-case scenario, the TDN predicted by the traditional 1D model was three times lower than the prediction of the multi-compartment model. The results delivered by the models differ also in the axial gradients. The traditional 1D model, for example, predicted an oxygen concentration at the membrane surface of 0.4 mg-O2/l while the multi-compartment model predicted a concentration of 2.9 mg-O2/l. Finally, the results of this study show that the longitudinal oxygen gradient has an important effect on both, biomass distribution and effluent TDN, whereas the longitudinal substrate exclusively affected the effluent TDN.},
}
@article {pmid31541515,
year = {2019},
author = {Amaechi, BT and Abdul Azees, PA and Menon, S and Kasundra, H},
title = {In vitro evaluation of the effects of Ultrasound Tongue Scraper on bacteria and biofilm formation.},
journal = {Journal of investigative and clinical dentistry},
volume = {},
number = {},
pages = {e12471},
doi = {10.1111/jicd.12471},
pmid = {31541515},
issn = {2041-1626},
support = {//Starmoon/ ; },
abstract = {AIM: Oral malodor is a common condition caused by some Gram-negative oral bacteria, among which are the 3 red complex bacteria (RCB). The present study investigated the effectiveness of the Ultrasound Tongue Scraper (UTS) to disrupt the structural morphology of the bacteria and their biofilm.<br><br>METHODS: While developing over 72 hours, multispecies biofilms of RCB (Porphromonas gingivalis, Tryponema denticola, Tannerella forsythia) were treated every 24 hours with 1.6-MHz ultrasound waves generated with UTS. An untreated group served as controls. Confocal laser scanning microscopy was used to determine the biofilm thickness, biomass and live : dead cell ratio at each time point (24, 48 and 72 hours). Biofilm morphology and bacteria ultrastructure were viewed using scanning/transmission electron microscopy, respectively. Data were analyzed using ANOVA and Tukey tests.<br><br>RESULTS: At each time point, the 3 variables were significantly lower in treated samples than the untreated. Significant biofilm disruption was observed in treated samples at each time period while the untreated had intact biofilm morphology. Cells in treated samples showed disrupted cell wall, cytoplasmic material, huge vacuoles and heterogeneity in electron density, while these cell organelles remained intact in untreated samples.<br><br>CONCLUSION: The UTS has an inhibitory effect on RCB and could be useful for oral malodor management.},
}
@article {pmid31540110,
year = {2019},
author = {Li, S and Wang, Y and Li, X and Lee, BS and Jung, S and Lee, MS},
title = {Enhancing the Thermo-Stability and Anti-Biofilm Activity of Alginate Lyase by Immobilization on Low Molecular Weight Chitosan Nanoparticles.},
journal = {International journal of molecular sciences},
volume = {20},
number = {18},
pages = {},
doi = {10.3390/ijms20184565},
pmid = {31540110},
issn = {1422-0067},
support = {NRF-2016R1A5A1011974//National Research Foundation of Korea (NRF)/ ; MBSMAT-2019-02//Key Lab of Marine Bioactive Substance and Modern Analytical Technique (SOA)/ ; ZR2019BD027//Shandong Provincial Natural Science Foundation/ ; KLGGOUC201703//Open Research Fund Program of Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology (Ocean University of China)/ ; },
abstract = {Bacterial biofilm causes severe antibiotic resistance. An extracellular polymeric substance (EPS) is the main component in the bacterial biofilm. Alginate is a key EPS component in the biofilm of Pseudomonas aeruginosa and responsible for surface adhesion and stabilization of biofilm. Alginate lyase has emerged as an efficient therapeutic strategy targeting to degrade the alginate in the biofilm of P. aeruginosa. However, the application of this enzyme is limited by its poor stability. In this study, chitosan nanoparticles (CS-NPs) were synthesized using low molecular weight chitosan and alginate lyase Aly08 was immobilized on low molecular weight chitosan nanoparticles (AL-LMW-CS-NPs). As a result, the immobilization significantly enhanced the thermal stability and reusability of Aly08. In addition, compared with free Aly08, the immobilized AL-LMW-CS-NPs exhibited higher efficiency in inhibiting biofilm formation and interrupting the established mature biofilm of P. aeruginosa, which could reduce its biomass and thickness confirmed by confocal microscopy. Moreover, the biofilm disruption greatly increased the antibiotic sensitivity of P. aeruginosa. This research will contribute to the further development of alginate lyase as an anti-biofilm agent.},
}
@article {pmid31539943,
year = {2019},
author = {Wang, X and Liu, B and Pan, X and Gadd, GM},
title = {Transport and retention of biogenic selenium nanoparticles in biofilm-coated quartz sand porous media and consequence for elemental mercury immobilization.},
journal = {The Science of the total environment},
volume = {692},
number = {},
pages = {1116-1124},
doi = {10.1016/j.scitotenv.2019.07.309},
pmid = {31539943},
issn = {1879-1026},
abstract = {Bacterial biofilms are structured cell communities embedded in a matrix of extracellular polymeric substances (EPS) and a ubiquitous growth form of bacteria in the environment. A wide range of interactions between biofilms and nanoparticles have been reported. In the present study, the influence of a mixed bacterial biofilm on retention of biogenic selenium nanoparticles (BioSeNPs) and consequences for immobilization of elemental mercury (Hg0) in a porous quartz sand system were examined. BioSeNPs were significantly retained in the presence of a biofilm through electrical double layer effects, hydrogen bonding, and hydrophobic, steric and bridging interactions. Moreover, enhanced surface roughness, pore clogging, sieving and entrapment effects mediated by the biofilm also contributed to deposition of BioSeNPs. Whereas, thiol groups associated with the biofilm is a little helpful for the capture of Hg0. It is proposed that oxidative complexation between Hg0 and thiol compounds or S containing organic matter in the biofilm may result in the formation of Hg2+-thiolate complexes and HgS during the binding of Hg0 with BioSeNPs. The formation of mercury selenide was also involved in Hg0 immobilization in the porous quartz sand system.},
}
@article {pmid31539312,
year = {2019},
author = {Cai, X and Yao, L and Sheng, Q and Jiang, L and Wang, T and Dahlgren, RA and Deng, H},
title = {Influence of a biofilm bioreactor on water quality and microbial communities in a hypereutrophic urban river.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-34},
doi = {10.1080/09593330.2019.1670267},
pmid = {31539312},
issn = {1479-487X},
abstract = {Biofilms play an important role in degradation, transformation and assimilation of anthropogenic pollutants in aquatic ecosystems. In this study, we assembled a tubular bioreactor containing a biofilm substrate and aeration device, which was introduced into mesocosms to explore the effects of bioreactor on physicochemical and microbial characteristics of a hypereutrophic urban river. The biofilm bioreactor greatly improved water quality, especially by decreasing dissolved inorganic nitrogen (DIN) concentrations, suggesting that biofilms were the major sites of nitrification and denitrification with an oxygen concentration gradient. The biofilm bioreactor increased the abundance of planktonic bacteria, whereas diversity of the planktonic microbial community decreased. Sequencing revealed that Proteobacteria, Bacteroidetes, Planctomycetes, and Actinobacteria were the four predominant phyla in the planktonic microbial community, and the presence of the biofilm bioreactor increased the relative abundance of Proteobacteria. Variations in microbial communities were most strongly affected by the presence of the biofilm bioreactor, as indicated by principal component analysis (PCA) and redundancy analysis (RDA). This study provides valuable insights into changes in ecological characteristics associated with self-purification processes in hypereutrophic urban rivers, and and may be of important for the application of biofilm bioreactor in natural urban river.},
}
@article {pmid31537970,
year = {2019},
author = {Bali, EB and Türkmen, KE and Erdönmez, D and Sağlam, N},
title = {Comparative Study of Inhibitory Potential of Dietary Phytochemicals Against Quorum Sensing Activity of and Biofilm Formation by Chromobacterium violaceum 12472, and Swimming and Swarming Behaviour of Pseudomonas aeruginosa PAO1.},
journal = {Food technology and biotechnology},
volume = {57},
number = {2},
pages = {212-221},
doi = {10.17113/ftb.57.02.19.5823},
pmid = {31537970},
issn = {1330-9862},
abstract = {Quorum sensing (QS) and biofilm formation are important mechanisms related to antibiotic resistance of many pathogens. Alternative treatments are needed to prevent recurrent or chronic infections caused by multi-resistant pathogens. Therefore, the aim of this study is to investigate and compare the inhibitory potential of the dietary phytochemicals: curcumin, quercetin, apigenin, pyrogallol, gallic acid and luteolin against QS of and biofilm formation by Chromobacterium violaceum ATCC 12472 and the swimming and swarming abilities of Pseudomonas aeruginosa PAO1. Anti-QS potential of the phytochemicals was evaluated qualitatively and quantitatively using C. violaceum via the disk diffusion assay based on violacein pigment inhibition at the subminimal inhibitory concentrations ranging from 46.87 to 750 µg/mL. The results of anti-QS and antibiofilm activities on C. violaceum demonstrated that all the phytochemicals except pyrogallol and gallic acid inhibited violacein production (from (11.0±0.1) to (88.2±0.1) %) in a concentration-dependent manner. In addition, the biofilm formation was also significantly inhibited (p<0.05) in the presence of all the phytochemicals ((1.38±0.08)-(84.2±0.2) %). In the present study, the results revealed that quercetin, curcumin, apigenin and luteolin could be promising QS and biofilm inhibitory agents against the C. violaceum 12472 biosensor system. Our findings also suggest that all the phytochemicals, especially curcumin, quercetin and pyrogallol, might be anti-pathogenic agents against P. aeruginosa PAO1 infections due to the ability to control QS. However, more comprehensive studies at the molecular level, explaining their anti-QS mechanisms, need to be conducted to confirm these results and identify the genes involved.},
}
@article {pmid31536440,
year = {2019},
author = {Abushahba, F and Söderling, E and Aalto-Setälä, L and Hupa, L and Närhi, TO},
title = {Air-Abrasion with bioactive glass eradicates S. mutans biofilm from sandblasted and acid etched titanium surface.},
journal = {The Journal of oral implantology},
volume = {},
number = {},
pages = {},
doi = {10.1563/aaid-joi-D-18-00324},
pmid = {31536440},
issn = {0160-6972},
abstract = {Streptococcus mutans is able to form a high-affinity biofilm on material surfaces. S. mutans has also been detected around infected implants. Bioactive glasses have been shown to possess antibacterial effects against S. mutans and other microorganisms. This in vitrostudy was performed to investigate the influence of bioactive glass air-abrasion on S. mutans biofilm on sandblasted and acid etched titanium surfaces. Sandblasted and acid etched commercially pure titanium discs were used as substrates for bacteria (n=107). The discs were immersed in an S. mutans solution and incubated for 21 h to form S. mutans biofilm. Twenty colonized discs were subjected to air-abrasion with the Bioglass®45S5 (45S5 BAG), experimental zinc oxide containing bioactive glass (Zn4 BAG) and inert glass. After the abrasion, the discs were incubated for 5 h in an anaerobic chamber followed by an assessment of viable S. mutans cells. Surface morphology was evaluation using SEM (n=12). Thrombogenicity of the glass particle abraded discs (n=75) was evaluated spectrophotometrically using whole blood clotting measurement at predetermined time points. Air-abrasion with 45S5 and Zn4 bioactive glass eradicated S. mutans biofilm. Significantly less viable S. mutans cells were found on discs abraded with the 45S5 or Zn4 BAGs compared to the inert glass (p<0.001). No significant differences were found in thrombogenicity since blood clotting was achieved for all substrates in min 40. Air-abrasion with BAG particles is effective in the eradication of S. mutans biofilm from sandblasted and acid etched titanium surfaces. Zn4 and 45S5 BAGs had similar biofilm eradicating effects but the Zn4 BAG could be more tissue-friendly. In addition, the steady release of zinc ions from the Zn4 may enhance the bone regeneration around the titanium implant and may thus have the potential to be used in the treatment of peri-implantitis. The use of either BAGs did not enhance the speed of blood coagulation.},
}
@article {pmid31535222,
year = {2019},
author = {Mello, DCR and de Oliveira, JR and Cairo, CAA and Ramos, LSB and Vegian, MRDC and de Vasconcellos, LGO and de Oliveira, FE and de Oliveira, LD and de Vasconcellos, LMR},
title = {Titanium alloys: in vitro biological analyzes on biofilm formation, biocompatibility, cell differentiation to induce bone formation, and immunological response.},
journal = {Journal of materials science. Materials in medicine},
volume = {30},
number = {9},
pages = {108},
doi = {10.1007/s10856-019-6310-2},
pmid = {31535222},
issn = {1573-4838},
support = {2012/20311-8//Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)/ ; },
abstract = {Biological effects of titanium (Ti) alloys were analyzed on biofilms of Candida albicans, Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans, and Streptococcus sanguinis, as well as on osteoblast-like cells (MG63) and murine macrophages (RAW 264.7). Standard samples composed of aluminum and vanadium (Ti-6Al-4V), and sample containing niobium (Ti-35Nb) and zirconium (Ti-13Nb-13Zr) were analyzed. Monomicrobial biofilms were formed on the Ti alloys. MG63 cells were grown with the alloys and the biocompatibility (MTT), total protein (TP) level, alkaline phosphatase (ALP) activity, and mineralization nodules (MN) formation were verified. Levels of interleukins (IL-1β and IL-17), tumor necrosis factor alpha (TNF-α), and oxide nitric (NO) were checked, from RAW 264.7 cells supernatants. Data were statically analyzed by one-way analysis of variance (ANOVA) and Tukey's test, or T-test (P ≤ 0.05). Concerning the biofilm formation, Ti-13Nb-13Zr alloy showed the best inhibitory effect on E. faecalis, P. aeruginosa, and S. aureus. And, it also acted similarly to the Ti-6Al-4V alloy on C. albicans and Streptococcus spp. Both alloys were biocompatible and similar to the Ti-6Al-4V alloy. Additionally, Ti-13Nb-13Zr alloy was more effective for cell differentiation, as observed in the assays of ALP and MN. Regarding the stimulation for release of IL-1β and TNF-α, Ti-35Nb and Ti-13Nb-13Zr alloys inhibited similarly the synthesis of these molecules. However, both alloys stimulated the production of IL-17. Additionally, all Ti alloys showed the same effect for NO generation. Thus, Ti-13Nb-13Zr alloy was the most effective for inhibition of biofilm formation, cell differentiation, and stimulation for release of immune mediators.},
}
@article {pmid31535132,
year = {2019},
author = {Oktay, EA and Ersahan, S and Sabuncuoglu, FA and Tort, H and Karaoglanoglu, S},
title = {Impact of various finishing and polishing techniques and composite materials on Candida albicans biofilm formation.},
journal = {Medical mycology},
volume = {},
number = {},
pages = {},
doi = {10.1093/mmy/myz095},
pmid = {31535132},
issn = {1460-2709},
abstract = {Candida albicans biofilms are commonly associated with severe oral infections. In dentistry, prosthetic and restorative materials are potential structures for the adhesion of C. albicans facilitating the formation of Candida biofilm and infection. Three composite resins (Charisma Classic, Sonic Fill, Estelite ∑ Quick) and two finishing-polishing systems (Biscover LV, Dental Finishing Disc) were evaluated for Candida biofilm formation. A Candida biofilm assay showed that both the resin and the finishing/polishing procedures affect Candida biofilm formation. Specifically, Candida biofilm formation was significantly lower in Sonic Fill resin than both Charisma Classic and Estelite ∑ Quick (P = .021). The type of finishing and polishing procedure also significantly affected the Candida biofilm formation to composite material (P < .001). Candida biofilm formation was more advanced after Biscover LV procedure than Dental Finishing Disc procedure.},
}
@article {pmid31534648,
year = {2019},
author = {Craft, KM and Nguyen, JM and Berg, LJ and Townsend, SD},
title = {Methicillin-resistant Staphylococcus aureus (MRSA): antibiotic-resistance and the biofilm phenotype.},
journal = {MedChemComm},
volume = {10},
number = {8},
pages = {1231-1241},
doi = {10.1039/c9md00044e},
pmid = {31534648},
issn = {2040-2511},
abstract = {Staphylococcus aureus (S. aureus) is an asymptomatic colonizer of 30% of all human beings. While generally benign, antibiotic resistance contributes to the success of S. aureus as a human pathogen. Resistance is rapidly evolved through a wide portfolio of mechanisms including horizontal gene transfer and chromosomal mutation. In addition to traditional resistance mechanisms, a special feature of S. aureus pathogenesis is its ability to survive on both biotic and abiotic surfaces in the biofilm state. Due to this characteristic, S. aureus is a leading cause of human infection. Methicillin-resistant S. aureus (MRSA) in particular has emerged as a widespread cause of both community- and hospital-acquired infections. Currently, MRSA is responsible for 10-fold more infections than all multi-drug resistant (MDR) Gram-negative pathogens combined. Recently, MRSA was classified by the World Health Organization (WHO) as one of twelve priority pathogens that threaten human health. In this targeted mini-review, we discuss MRSA biofilm production, the relationship of biofilm production to antibiotic resistance, and front-line techniques to defeat the biofilm-resistance system.},
}
@article {pmid31533204,
year = {2019},
author = {Weng, PL and Ramli, R and Hamat, RA},
title = {Antibiotic Susceptibility Patterns, Biofilm Formation and esp Gene among Clinical Enterococci: Is There Any Association?.},
journal = {International journal of environmental research and public health},
volume = {16},
number = {18},
pages = {},
doi = {10.3390/ijerph16183439},
pmid = {31533204},
issn = {1660-4601},
abstract = {Enterococci are commonly found in humans, animals and environments. Their highly adaptive mechanisms are related to several virulent determinants and their ability to resist antibiotics. Data on the relationship between the esp gene, biofilm formation and antibiotic susceptibility profiles may differ between countries. This cross-sectional study was conducted to determine the proportion of esp gene and biofilm formation among Enterococcus faecalis and Enterococcus faecium clinical isolates. We also investigated the possible association between the esp gene with antibiotic susceptibility patterns and biofilm formation. The isolates were collected from clinical samples and identified using biochemical tests and 16SRNA. Antibiotic susceptibility patterns and a biofilm assay were conducted according to the established guidelines. Molecular detection by PCR was used to identify the esp gene using established primers. In total, 52 and 28 of E. faecalis and E. faecium were identified, respectively. E. faecium exhibited higher resistance rates compared to E. faecalis as follows: piperacillin/tazobactam (100% versus 1.9%), ampicillin (92.8% versus 1.9%), high-level gentamicin resistance (HLGR) (89.3% versus 25.0%) and penicillin (82.1% versus 7.7%). E. faecium produced more biofilms than E. faecalis (59.3% versus 49.0%). E. faecium acquired the esp gene more frequently than E. faecalis (78.6% versus 46.2%). Interestingly, the associations between ampicillin and tazobactam/piperacillin resistance with the esp gene were statistically significant (X2 = 4.581, p = 0.027; and X2 = 6.276, p = 0.012, respectively). Our results demonstrate that E. faecium exhibits high rates of antimicrobial resistance, esp gene acquisition and biofilm formation. These peculiar traits of E. faecium may have implications for the management of enterococcal infections in hospitals. Thus, concerted efforts by all parties in establishing appropriate treatment and effective control measures are warranted in future.},
}
@article {pmid31533083,
year = {2019},
author = {Preetham, E and Rubeena, AS and Vaseeharan, B and Chaurasia, MK and Arockiaraj, J and Olsen, RE},
title = {Anti-biofilm properties and immunological response of an immune molecule lectin isolated from shrimp Metapenaeus monoceros.},
journal = {Fish &amp; shellfish immunology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.fsi.2019.09.032},
pmid = {31533083},
issn = {1095-9947},
abstract = {The study is carried out to understand the antimicrobial and immunological response of a potential immune molecule lectin, MmLec isolated from haemolymph of Speckled shrimp, Metapenaeus monoceros. MmLec was purified using mannose coupled Sepharose CL-4B affinity chromatography, which was further subjected on SDS-PAGE to ascertain the distribution of their molecular weight. Sugar binding specificity assay was conducted at various pH and temperatures to investigate the binding affinity of MmLec towards the specific carbohydrate molecule. Functional analysis of immune molecule MmLec included haemagglutination assays performed using human erythrocytes and yeast agglutination activity against Saccharomyces cerevisiae which, were analyzed using light microscopy. In order to study the antimicrobial activity, two Gram-negative (Vibrio parahaemolyticus and Aeromonas hydrophila) and two Gram-positive (Staphylococcus aureus and Enterococcus faecalis) bacteria were treated with purified MmLec. Moreover, these bacterial species were also treated at different concentration of the MmLec to speculate the antibiofilm properties of MmLec which was analyzed under Light Microscopy and Confocal Laser Scanning Microscopy. In addition, other functional characterization of MmLec showed the uniqueness of MmLec in agglutination of human erythrocyte as well as the cells of yeast Saccharomyces cerevisiae. Also, the phenoloxidase activity and encapsulation assay was evaluated. MTT assay displayed that MmLec are potent in anticancer activity. The study will help to understand the immunological interference and antimicrobial nature of MmLec which would be supportive in establishing a potential therapeutic tool and to develop better and novel disease control strategies in shrimp and farmed aquaculture industries as well as in health management.},
}
@article {pmid31533077,
year = {2019},
author = {Vijayakumar, K and Ramanathan, T},
title = {Musa acuminata and its bioactive metabolite 5-Hydroxymethylfurfural mitigates quorum sensing (las and rhl) mediated biofilm and virulence production of nosocomial pathogen Pseudomonas aeruginosa in vitro.},
journal = {Journal of ethnopharmacology},
volume = {},
number = {},
pages = {112242},
doi = {10.1016/j.jep.2019.112242},
pmid = {31533077},
issn = {1872-7573},
abstract = {Musa acuminata, a tropical plant belongs to the family Musaceae. The fruit peels of this plant have been well documented for their therapeutic value in Asia and Africa. It has also been previously reported for numerous biological applications such as antimicrobial, antioxidant, itching, psoriasis and anti-diarrheal activities. Moreover, M. acuminata peels have been well known for its anti-healing and antiseptic properties and most commonly used for healing wounds and heat burns in South Asian and African traditional medicines.<br><br>AIM OF THE STUDY: To evaluate the QS-mediated antibiofilm and antivirulence potential of M. acuminata, and its bioactive metabolites 5-Hydroxymethylfurfural (5HMF) against Pseudomonas aeruginosa.<br><br>MATERIALS AND METHODS: The M. acuminata peel methanol extract (MAM) was evaluated for its antibiofilm potential against P. aeruginosa with increasing concentration. Besides, biofilm related phenomenon's such as total biofilm proteins, microcolony formation exopolysaccharides (EPS) and cell surface hydrophobicity (CSH) productions were also examined to support the antibiofilm potential of MAM. Further, MAM was evaluated for its antivirulence efficacy against P. aeruginosa by assessing the protease, LasA protease, LasB elastase, pyocyanin, alginate and rhamnolipid productions at 400 μg ml-1 concentration. Transcriptional analysis of QS regulated virulence genes expression level was also done by real-time PCR analysis. Then, the MAM was subjected to column chromatography for further fractions and the bioactive compounds present in MAM were identified by gas chromatograph-mass spectrometry analysis. Further, the major compounds such as 5-hydroxymethylfurfural, vaccenic acid and pentanoic acid identified from active fraction of MAM were evaluated for their antibiofilm and antivirulence potential against P. aeruginosa.<br><br>RESULTS: MAM significantly inhibited the biofilm formation in P. aeruginosa at 400 μg ml-1 concentration which also inhibited the production of biofilm proteins, biofilm adherence, EPS and CSH productions to the level of 79%, 82% and 77% respectively. Further, the antivirulence potential was confirmed through numerous virulence inhibition assays. The MAM at 400 μg ml-1 concentration inhibited the QS-mediated virulence production such as protease, LasA protease, LasB elastase, pyocyanin, alginate and rhamnolipid productions to the level of 77%, 75%, 68%, 80%, 78% and 69% respectively. Moreover, the results of qPCR analysis confirmed the downregulation of QS regulated virulence genes expression upon treatment with MAM. The chromatographic analysis revealed the presence of 5-Hydroxymethylfurfural (5HMF), vaccenic acid and pentanoic acid in MAM and the potential bioactive compounds with antibiofilm and antivirulence was identified as 5-hydroxymethylfurfural, without exerting any growth inhibition in P. aeruginosa.<br><br>CONCLUSION: This study investigated the ideal antibiofilm and antivirulence potential of MAM and its bioactive compound 5HMF, and confirms the ethnopharmacological value of these peels against P. aeruginosa infections.},
}
@article {pmid31532581,
year = {2019},
author = {She, P and Wang, Y and Liu, Y and Tan, F and Chen, L and Luo, Z and Wu, Y},
title = {Effects of exogenous glucose on Pseudomonas aeruginosa biofilm formation and antibiotic resistance.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e933},
doi = {10.1002/mbo3.933},
pmid = {31532581},
issn = {2045-8827},
support = {20150309//The New Xiangya Talent Project of The Third Xiangya Hospital of Central South University/ ; },
abstract = {Pseudomonas aeruginosa is commonly found in nosocomial and life-threatening infections in patients. Biofilms formed by P. aeruginosa exhibit much greater resistance to antibiotics than the planktonic form of the bacteria. Few groups have studied the effects of glucose, a major carbon source, and metabolite, on P. aeruginosa biofilm formation and on its metabolic pathways. In this study, we investigated the effect of glucose on the biofilm formation ability of P. aeruginosa and carried out a metabolomic analysis to identify whether glucose alters the metabolic activity of P. aeruginosa in biofilms. We found that glucose efficiently promoted P. aeruginosa biofilm formation by upregulating the expression of the extracellular polysaccharide-related gene pslA. Treatment with glucose caused an increase in 7 metabolites (including 3-hydroxypropionic acid, glucose-6-phosphate, and 2,3-dimethylsuccinic acid) and a decrease in 18 metabolites (including myo-inositol, glutamine, and methoxamedrine) in the biofilm. In addition, there was a synergistic effect between glucose and horse serum on biofilm formation when the two were added in combination, which also increased the resistance of biofilm to levofloxacin therapy. Thus, our work sheds light on the underlying mechanisms by which glucose may enhance biofilm formation and identifies novel targets for developing strategies to counteract biofilm formation.},
}
@article {pmid31532251,
year = {2019},
author = {Wang, H and Palmer, J and Flint, S},
title = {Function of pYV Plasmid on Biofilm Formation of Yersinia enterocolitica ERL032123 in the Presence of Ca2.},
journal = {Journal of food protection},
volume = {},
number = {},
pages = {1683-1687},
doi = {10.4315/0362-028X.JFP-19-018},
pmid = {31532251},
issn = {1944-9097},
abstract = {The effect of the virulence plasmid pYV and calcium ions on biofilm of Yersinia enterocolitica biofilm formation was determined using a microtiter plate assay. Loss of the pYV plasmid prevented biofilm formation and the presence of Ca2+ enhanced biofilm formation in cultures containing the pYV plasmid. Scanning electron microscopy supported the result from the microtiter plate assay showing that in the presence of Ca2+, the wild-type Y. enterocolitica strain formed a strong biofilm on a polycarbonate surface. The results implied that Ca2+ promotes Y. enterocolitica biofilm formation through the function of the pYV plasmid.},
}
@article {pmid31531452,
year = {2019},
author = {Baumeister, TUH and Staudinger, M and Wirgenings, M and Pohnert, G},
title = {Halogenated anilines as novel natural products from a marine biofilm forming microalga.},
journal = {Chemical communications (Cambridge, England)},
volume = {},
number = {},
pages = {},
doi = {10.1039/c9cc05992j},
pmid = {31531452},
issn = {1364-548X},
abstract = {The toxic halogenated anilines 2,4,6-tribromoaniline, 2,4,6-trichloroaniline and their dibromochloro and bromodichloro derivatives were considered as compounds of exclusive synthetic origin. Labeling studies and kinetic experiments confirmed that these substances are also biosynthesized by a marine biofilm forming microalga. They represent a novel class of halogenated natural products.},
}
@article {pmid31531409,
year = {2019},
author = {Hwang, G and Paula, AJ and Hunter, EE and Liu, Y and Babeer, A and Karabucak, B and Stebe, K and Kumar, V and Steager, E and Koo, H},
title = {Catalytic antimicrobial robots for biofilm eradication.},
journal = {Science robotics},
volume = {4},
number = {29},
pages = {},
doi = {10.1126/scirobotics.aaw2388},
pmid = {31531409},
issn = {2470-9476},
abstract = {Magnetically driven robots can perform complex functions in biological settings with minimal destruction. However, robots designed to damage deleterious biostructures could also have important impact. In particular, there is an urgent need for new strategies to eradicate bacterial biofilms as we approach a post-antibiotic era. Biofilms are intractable and firmly attached structures ubiquitously associated with drug-resistant infections and destruction of surfaces. Existing treatments are inadequate to both kill and remove bacteria leading to reinfection. Here we design catalytic antimicrobial robots (CARs) that precisely and controllably kill, degrade and remove biofilms with remarkable efficiency. CARs exploit iron oxide nanoparticles (NPs) with dual catalytic-magnetic functionality that (i) generate bactericidal free radicals, (ii) breakdown the biofilm exopolysaccharide (EPS) matrix, and (iii) remove the fragmented biofilm debris via magnetic field driven robotic assemblies. We develop two distinct CAR platforms. The first platform, the biohybrid CAR, is formed from NPs and biofilm degradation products. After catalytic bacterial killing and EPS disruption, magnetic field gradients assemble NPs and the biodegraded products into a plow-like superstructure. When driven with an external magnetic field, the biohybrid CAR completely removes biomass in a controlled manner, preventing biofilm regrowth. Biohybrid CARs can be swept over broad swathes of surface or can be moved over well-defined paths for localized removal with microscale precision. The second platform, the 3D molded CAR, is a polymeric soft robot with embedded catalytic-magnetic NPs, formed in a customized 3D printed mold to perform specific tasks in enclosed domains. Vane-shaped CARs remove biofilms from curved walls of cylindrical tubes, and helicoid-shaped CARs drill through biofilm clogs, while simultaneously killing bacteria. In addition, we demonstrate applications of CARs to target highly confined anatomical surfaces in the interior of human teeth. These 'kill-degrade-and-remove' CARs systems could have significant impact in fighting persistent biofilm-infections and in mitigating biofouling of medical devices and diverse surfaces.},
}
@article {pmid31531109,
year = {2019},
author = {Veloz, JJ and Alvear, M and Salazar, LA},
title = {Evaluation of Alternative Methods to Assess the Biological Properties of Propolis on Metabolic Activity and Biofilm Formation in Streptococcus mutans.},
journal = {Evidence-based complementary and alternative medicine : eCAM},
volume = {2019},
number = {},
pages = {1524195},
doi = {10.1155/2019/1524195},
pmid = {31531109},
issn = {1741-427X},
abstract = {Several biological activities have been reported for the Chilean propolis, among their antimicrobial and antibiofilm properties, due to its high polyphenol content. In this study, we evaluate alternative methods to assess the effect of Chilean propolis on biofilm formation and metabolic activity of Streptococcus mutans (S. mutans), a major cariogenic agent in oral cavity. Biofilm formation was studied by using crystal violet and by confocal microscopy. The metabolic activity of biofilm was evaluated by MTT and by flow cytometry analysis. The results show that propolis reduces biofilm formation and biofilm metabolic activity in S. mutans. When the variability of the methods to measure biofilm formation was compared, the coefficient of variation (CV) fluctuated between 12.8 and 23.1% when using crystal violet methodology. On the other hand, the CV ranged between 2.2 and 3.3% with confocal microscopy analysis. The CV for biofilm's metabolic activity measured by MTT methodology ranged between 5.0 and 11.6%, in comparison with 1.9 to 3.2% when flow cytometry analysis was used. Besides, it is possible to conclude that the methods based on colored compounds presented lower precision to study the effect of propolis on biofilm properties. Therefore, we recommend the use of flow cytometry and confocal microscopy in S. mutans biofilm analysis.},
}
@article {pmid31530887,
year = {2019},
author = {Marbach, H and Mayer, K and Vogl, C and Lee, JYH and Monk, IR and Sordelli, DO and Buzzola, FR and Ehling-Schulz, M and Grunert, T},
title = {Within-host evolution of bovine Staphylococcus aureus selects for a SigB-deficient pathotype characterized by reduced virulence but enhanced proteolytic activity and biofilm formation.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {13479},
doi = {10.1038/s41598-019-49981-6},
pmid = {31530887},
issn = {2045-2322},
support = {FWF-P29304-B22//Austrian Science Fund (Fonds zur F&amp;#x00F6;rderung der Wissenschaftlichen Forschung)/ ; PP14311265//Veterin&amp;#x00E4;rmedizinische Universit&amp;#x00E4;t Wien (University of Veterinary Medicine, Vienna)/ ; },
abstract = {Staphylococcus aureus is a major cause of bovine mastitis, commonly leading to long-lasting, persistent and recurrent infections. Thereby, S. aureus constantly refines and permanently adapts to the bovine udder environment. In this work, we followed S. aureus within-host adaptation over the course of three months in a naturally infected dairy cattle with chronic, subclinical mastitis. Whole genome sequence analysis revealed a complete replacement of the initial predominant variant by another isogenic variant. We report for the first time within-host evolution towards a sigma factor SigB-deficient pathotype in S. aureus bovine mastitis, associated with a single nucleotide polymorphism in rsbU (G368A → G122D), a contributor to SigB-functionality. The emerged SigB-deficient pathotype exhibits a substantial shift to new phenotypic traits comprising strong proteolytic activity and poly-N-acetylglucosamine (PNAG)-based biofilm production. This possibly unlocks new nutritional resources and promotes immune evasion, presumably facilitating extracellular persistence within the host. Moreover, we observed an adaptation towards attenuated virulence using a mouse infection model. This study extends the role of sigma factor SigB in S. aureus pathogenesis, so far described to be required for intracellular persistence during chronic infections. Our findings suggest that S. aureus SigB-deficiency is an alternative mechanism for persistence and underpin the clinical relevance of staphylococcal SigB-deficient variants which are consistently isolated during human chronic infections.},
}
@article {pmid31529027,
year = {2019},
author = {Bjarnsholt, T and Østrup Jensen, P and Alhede, M},
title = {Revival of Krebs-Ringer balanced salt solution for the investigation of polymorphonuclear leukocytes and Pseudomonas aeruginosa biofilm interaction.},
journal = {Pathogens and disease},
volume = {},
number = {},
pages = {},
doi = {10.1093/femspd/ftz052},
pmid = {31529027},
issn = {2049-632X},
abstract = {To study the interaction between aggregating bacteria and polymorphonuclear leukocytes (PMNs) in vitro the chosen medium must favor both the isolated PMNs and the bacteria. To investigate the best-suited medium for the in vitro survival of isolated unactivated human PMNs, we compared three different mammalian cell media: Krebs-Ringer balanced salt solution (BSS), Hanks' BSS (HBSS) and Roswell Park Memorial Institute (RPMI) 1640. The death of PMNs was estimated as the release of lactate dehydrogenase activity. Furthermore, two types of serum, human (HS) and fetal bovine (FBS), were compared at different concentrations (0%, 2%, 5%, 10%) and at three different time points (2, 4, 20 h). We show that Krebs-Ringer BSS prolonged the survival of PMNs compared to HBSS and RPMI1640 and that the addition of 10% FBS significantly enhanced long-term survival (20 h) compared to HS. Furthermore, we observed aggregation of Pseudomonas aeruginosa when grown in the presence of either a mixture of histones, histone H3, arginine or lysine. In this study, we show that the use of Krebs-Ringer BSS is highly relevant for the study of the interaction of bacteria and PMNs in relation to novel treatment strategies of biofilm infections due to the reproduction of bacterial aggregation as seen in chronic bacterial infections.},
}
@article {pmid31528252,
year = {2019},
author = {Song, YG and Lee, SH},
title = {Efficacy of newly developed denture cleaning device on physical properties of denture material and Candida biofilm.},
journal = {Journal of dental sciences},
volume = {14},
number = {3},
pages = {248-254},
doi = {10.1016/j.jds.2019.01.011},
pmid = {31528252},
issn = {2213-8862},
abstract = {Background/purpose: Electrolyzed water has antimicrobial activity against oral microbes. The purpose of this study was to investigate the effects of a denture cleaning device that uses electrolyzed water on Candida biofilm on denture base-material and the physical properties of the denture material.<br><br>Materials and methods: Denture base-resin disks were prepared with Polymethyl methacrylate. After the formation of Candida albicans biofilm on the resin disks, the antimicrobial activity of the denture cleaning device and the chemical cleanser against C. albicans biofilm was compared. The resin disks were also treated with the cleaning device and the chemical cleanser for 150 days, and the physical properties were analyzed by an atomic force microscope, Vickers hardness tester, and colorimeter.<br><br>Results: The denture cleaning device and the chemical cleanser reduced the levels of C. albicans biofilm on the denture resin. Upon immersing of the resin disks for 150 days, the electrolyzed water of the denture cleaning device did not significantly change the surface roughness of the specimens, but significantly reduced its Vickers hardness compared to the initial value. The color changes of the resin disk were 0.477 ± 0.076, 0.612 ± 0.095 and 0.562 ± 0.096 after treating with tap water, the chemical cleanser, and the denture cleaning device, respectively.<br><br>Conclusion: The denture cleaning device may be suitable for use by the elderly to clean dentures without side effects caused by the misuse of chemical cleanser.},
}
@article {pmid31528123,
year = {2019},
author = {Thieme, L and Hartung, A and Tramm, K and Klinger-Strobel, M and Jandt, KD and Makarewicz, O and Pletz, MW},
title = {MBEC Versus MBIC: the Lack of Differentiation between Biofilm Reducing and Inhibitory Effects as a Current Problem in Biofilm Methodology.},
journal = {Biological procedures online},
volume = {21},
number = {},
pages = {18},
doi = {10.1186/s12575-019-0106-0},
pmid = {31528123},
issn = {1480-9222},
abstract = {Background: Biofilms are communities of aggregated, matrix-embedded microbial cells showing a high tolerance to an in principle adequate antibiotic therapy, often resulting in treatment failure. A major challenge in the management of biofilm-associated infections is the development of adequate, standardized biofilm susceptibility testing assays that are clinically meaningful, i.e. that their results correlate with treatment outcome. Different biofilm susceptibility endpoint parameters like the minimal biofilm eradication concentration (MBEC) or the minimal biofilm inhibitory concentration (MBIC) have been suggested as a guide for treatment of biofilm-associated infections, however with inconsistent perception and use among biofilm researchers, leading to confusion and contradictions among different anti-biofilm component studies and clinical trials.<br><br>Findings: Evaluation of anti-biofilm effects is mostly based on the untreated reference growth control biofilm measured at the same endpoint as the treated biofilm, neglecting the possible change of the untreated reference biofilm from the time point of pre-antimicrobial exposure to the measured endpoint. In this commentary, we point out the importance of individual quantification of mature, established biofilms before antimicrobial treatment for each biofilm model in order to draw conclusions on the measured biofilm effect size, i.e. biofilm reducing (MBEC) or biofilm inhibitory (MBIC) effects.<br><br>Conclusion: The assessment of pre-treatment biofilms contributes to a standardized use of biofilm susceptibility endpoint parameters, which is urgently needed to improve the clinical validity of future anti-biofilm assays.},
}
@article {pmid31527127,
year = {2019},
author = {Sultan, AR and Hoppenbrouwers, T and Lemmens-den Toom, NA and Snijders, SV and van Neck, JW and Verbon, A and de Maat, MPM and van Wamel, WJB},
title = {During the Early Stages of Staphylococcus aureus Biofilm Formation, induced Neutrophil Extracellular Traps (NETs) are degraded by Autologous Thermonuclease.},
journal = {Infection and immunity},
volume = {},
number = {},
pages = {},
doi = {10.1128/IAI.00605-19},
pmid = {31527127},
issn = {1098-5522},
abstract = {Staphylococcus aureus extracellular DNA (eDNA) plays a crucial role in the structural stability of biofilms during bacterial colonization, on the contrary, host immune responses can be induced by bacterial eDNA. Previously we observed production of S. aureus thermonuclease during the early stages of biofilm formation in a mammalian cell culture medium. Using a fluorescence resonance energy transfer (FRET)-based assay, we detected thermonuclease activity of S. aureus biofilms grown in Iscove's modified Dulbecco's medium (IMDM) earlier compared to widely-studied tryptic soy broth (TSB) grown biofilms. The thermonuclease found was Nuc1, confirmed by mass spectrometry and competitive Luminex assay. These results indicate that biofilm development in IMDM may not rely on eDNA for structural stability. A bacterial viability assay in combination with wheat germ agglutinin (WGA) staining confirmed the accumulation of dead cells and eDNA in biofilms grown in TSB. However, in IMDM-grown biofilms minimal amounts of eDNA were found and instead, polysaccharide intercellular adhesin (PIA) was detected. To investigate if this early production of thermonuclease plays a role in immune modulation by biofilm, we studied the effect of thermonuclease on human neutrophil extracellular traps (NETs) formation using a nuc knockout and complemented strain. We confirmed that thermonuclease produced by early stages biofilms grown in IMDM degraded biofilm-induced NETs. Additionally, neither the presence of biofilms nor thermonuclease stimulated an increase in reactive oxygen species (ROS) production by neutrophils. Our findings indicated that S. aureus, during the early stages of biofilm formation, actively evades the host immune responses by producing thermonuclease.},
}
@article {pmid31525949,
year = {2019},
author = {Wang, ZH and Liu, JM and Li, CY and Wang, D and Lv, H and Lv, SW and Zhao, N and Ma, H and Wang, S},
title = {Bacterial Biofilm Bioinspired Persistent Luminescence Nanoparticles with Gut-Oriented Drug Delivery for Colorectal Cancer Imaging and Chemotherapy.},
journal = {ACS applied materials &amp; interfaces},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsami.9b12853},
pmid = {31525949},
issn = {1944-8252},
abstract = {Colorectal cancer (CRC) now comes to be one of the leading causes of cancer incidence and mortality. Although nanomaterial-based drug delivery has been used for the treatment of colorectal cancer, inferior targeting ability of existing nanocarriers leads to inefficient treatment and side effects. Moreover, the majority of intravenously administered nanomaterials aggregate into the reticuloendothelial system, leaving certain hidden risk to human health. All those problems gave great demands for further construction of well-performed and biocompatible nanomaterials for in vivo theranostics. In the present work, from a biomimetic point of view, Lactobacillus reuteri biofilm (LRM) was coated on the surface of trackable zinc gallogermanate (ZGGO) near-infrared persistent luminescence mesoporous silica to create the bacteria bioinspired nanoparticles (ZGGO@SiO2@LRM), which hold the inherit capability of withstanding the digestion of gastric acid and targeted release 5-FU to colorectum. Through the background-free persistent luminescence bioimaging of ZGGO, the coating of LRM facilitated the localization of ZGGO@SiO2@LRM to the tumor area of colorectum for more than 24 h after intragastric administration. Furthermore, ZGGO@SiO2@LRM hardly entered the blood, which avoided possible damage to immune organs such as liver and spleen. In vivo chemotherapy experiment clearly demonstrated the number of tumors per mouse in ZGGO@SiO2@LRM group decreased by one-half compared with the 5-FU group (P < 0.001). To sum up, this LRM bioinspired nanoparticles could tolerate the digestion of gastric acid, aviod aggregation by the immune system, favor gut-oriented drug delivery, and targeted release oral 5-FU into colorectum for more than 24 h, which may give new application prospects for targeted delivery of oral drugs into the colorectum.},
}
@article {pmid31524581,
year = {2019},
author = {Brown, JL and Johnston, W and Delaney, C and Short, B and Butcher, MC and Young, T and Butcher, J and Riggio, M and Culshaw, S and Ramage, G},
title = {Polymicrobial oral biofilm models: simplifying the complex.},
journal = {Journal of medical microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1099/jmm.0.001063},
pmid = {31524581},
issn = {1473-5644},
abstract = {Over the past century, numerous studies have used oral biofilm models to investigate growth kinetics, biofilm formation, structure and composition, antimicrobial susceptibility and host-pathogen interactions. In vivo animal models provide useful models of some oral diseases; however, these are expensive and carry vast ethical implications. Oral biofilms grown or maintained in vitro offer a useful platform for certain studies and have the advantages of being inexpensive to establish and easy to reproduce and manipulate. In addition, a wide range of variables can be monitored and adjusted to mimic the dynamic environmental changes at different sites in the oral cavity, such as pH, temperature, salivary and gingival crevicular fluid flow rates, or microbial composition. This review provides a detailed insight for early-career oral science researchers into how the biofilm models used in oral research have progressed and improved over the years, their advantages and disadvantages, and how such systems have contributed to our current understanding of oral disease pathogenesis and aetiology.},
}
@article {pmid31523511,
year = {2019},
author = {Pelyuntha, W and Chaiyasut, C and Kantachote, D and Sirilun, S},
title = {Cell-free supernatants from cultures of lactic acid bacteria isolated from fermented grape as biocontrol against Salmonella Typhi and Salmonella Typhimurium virulence via autoinducer-2 and biofilm interference.},
journal = {PeerJ},
volume = {7},
number = {},
pages = {e7555},
doi = {10.7717/peerj.7555},
pmid = {31523511},
issn = {2167-8359},
abstract = {Background: Salmonella Typhi and Salmonella Typhimurium are the causative pathogens of salmonellosis, and they are mostly found in animal source foods (ASF). The inappropriate use of antibiotics enhances the possibility for the emergence of antibiotic resistance in pathogens and antibiotic residue in ASF. One promising alternative to antibiotics in animal farming is the use of lactic acid bacteria (LAB).<br><br>Methods: The present study was carried out the cells and/or the cell-free culture supernatants (CFCS) from beneficial LAB against S. Typhi and S. Typhimurium. The antibacterial mechanisms of LAB-CFCS as biocontrol agents against both Salmonella serovars were investigated through the analysis of anti-salmonella growth activity, biofilm inhibition and quorum quenching activity.<br><br>Results: Among 146 LAB strains isolated from 110 fermented food samples, the 2 strong inhibitory effect strains (WM33 and WM36) from fermented grapes against both Salmonella serovars were selected. Out of the selected strains, WM36 was the most effective inhibitor, which indicated S. Typhi by showing 95.68% biofilm inhibition at 20% biofilm inhibition concentration (BIC) and reduced 99.84% of AI-2 signaling interference. The WM33 was the best to control S. Typhimurium by producing 66.46% biofilm inhibition at only 15% BIC and 99.99% AI-2 signaling a reduction. The 16S rDNA was amplified by a polymerase chain reaction (PCR). The selected isolates were identified as Weissella viridescens WM33 and Weissella confusa WM36 based on nucleotide homology and phylogenetic analysis.<br><br>Conclusion: The metabolic extracts from Weissella spp. inhibit Salmonella serovars with the potential to be used as biocontrol agents to improve microbiological safety in the production of ASF.},
}
@article {pmid31523409,
year = {2019},
author = {Saidi, N and Owlia, P and Marashi, SMA and Saderi, H},
title = {Inhibitory effect of probiotic yeast Saccharomyces cerevisiae on biofilm formation and expression of α-hemolysin and enterotoxin A genes of Staphylococcus aureus.},
journal = {Iranian journal of microbiology},
volume = {11},
number = {3},
pages = {246-254},
pmid = {31523409},
issn = {2008-3289},
abstract = {Background and Objectives: Staphylococcus aureus, as an opportunistic pathogen, is the cause of a variety of diseases from mild skin infections to severe invasive infections and food poisoning. Increasing antibiotic resistance in S. aureus isolates has become a major threat to public health. The use of compounds produced by probiotics can be a solution to this problem. Thus, the purpose of this study was to investigate the effect of Saccharomyces cerevisiae on some virulence factors (biofilm, α-hemolysin, and enterotoxin A) of S. aureus.<br><br>Materials and Methods: Supernatant and lysate extracts were prepared from S. cerevisiae S3 culture. Sub-MIC concentrations of both extracts were separately applied to S. aureus ATCC 29213 (methicillin-sensitive S. aureus; MSSA) and S. aureus ATCC 33591 (methicillin-resistant S. aureus; MRSA) strains. Biofilm formation of these strains was measured by microtiter plate assay and expression level of α-hemolysin and enterotoxin A genes (hla and sea, respectively) using real-time PCR technique.<br><br>Results: The supernatant extract has reduced both biofilm formation and expression of sea and hla genes, while lysate extract had only anti-biofilm effects. The MRSA strain showed more susceptibility to yeast extracts than MSSA strain in all tests.<br><br>Conclusion: The present study exhibited favorable antagonistic effects of S. cerevisiae S3, as a probiotic yeast, on MSSA and MRSA strains. Based on the findings of this study, the compounds produced by this yeast can be used to control S. aureus infections; however, further similar studies should be conducted to confirm the findings of the present study.},
}
@article {pmid31523169,
year = {2019},
author = {Liu, J and Cai, M and Yan, H and Fu, J and Wu, G and Zhao, Z and Zhao, Y and Wang, Y and Sun, Y and You, Y and Lin, L and Huang, J and Huang, R and Zeng, J},
title = {Yunnan Baiyao reduces hospital-acquired pressure ulcers via suppressing virulence gene expression and biofilm formation of Staphylococcus aureus.},
journal = {International journal of medical sciences},
volume = {16},
number = {8},
pages = {1078-1088},
doi = {10.7150/ijms.33723},
pmid = {31523169},
issn = {1449-1907},
abstract = {Yunnan Baiyao (YB) as a kind of famous Chinese herbal medicine, possessed hemostatic, invigorating the circulation of blood, and anti-inflammatory effects. Identifying strategies to protect patients at risk for hospital-acquired pressure ulcers (HAPU) is essential. Herein, our results showed that YB treatment can effectively reduce the acne wound area and improve efficacy in a comparative study of 60 cases HAPU patients with S. aureus positive of acne wound pathogens. Furthermore, YB inhibited HIa expression and suppressed accessory gene regulator (agr) system controlled by regulatory RNA II and RNA III molecule using pALC1740, pALC1742 and pALC1743 S. aureus strain linked to gfpuvr reporter gene. Moreover, YB downregulated cao mRNA expression and inhibited coagulase activity by RT-PCR, slide and tube coagulase test. Additionally, YB downregulated seb, sec, sed, and tsst-1 mRNA expression to suppress enterotoxin and tsst-1 secretion and adhesion function related genes sarA, icaA, and cidA mRNA expression. Taken together, the data suggest that YB may reduce HAPU via suppressing virulence gene expression and biofilm formation of S. aureus.},
}
@article {pmid31521779,
year = {2019},
author = {Alfa, MJ and Singh, H},
title = {Impact of wet storage and other factors on biofilm formation and contamination of patient-ready endoscopes: a narrative review.},
journal = {Gastrointestinal endoscopy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.gie.2019.08.043},
pmid = {31521779},
issn = {1097-6779},
abstract = {The 2019 Food and Drug Administration report indicates that the clinical studies undertaken by the 3 main GI endoscope manufacturers demonstrate 5.4% of patient-ready duodenoscopes remain culture positive for high-concern organisms. The root causes of this persistent contamination are poorly understood. The objectives of this review include summarizing (1) the impact of inadequate manual cleaning, and inadequate drying during storage on the formation of build-up biofilm in endoscope channels, (2) the impact of de-foaming agents used during patient procedures on drying efficacy, (3) the data showing the importance of build-up biofilm on persistent microbial survival, and (4) potential impact of implementation of a Quality Systems approach in GI endoscopy reprocessing.},
}
@article {pmid31521732,
year = {2019},
author = {Horiuchi, A and Kokubu, E and Warita, T and Ishihara, K},
title = {Synergistic biofilm formation by Parvimonas micra and Fusobacterium nucleatum.},
journal = {Anaerobe},
volume = {},
number = {},
pages = {102100},
doi = {10.1016/j.anaerobe.2019.102100},
pmid = {31521732},
issn = {1095-8274},
abstract = {Parvimonas micra is frequently isolated from lesions of apical periodontitis and is a major disease-related pathogen. One of the main causes of apical periodontitis is extraradicular biofilm. In this study, we investigated polymicrobial biofilm formation by P. micra and species associated with apical periodontitis. The coaggregation activity of P. micra with partner strains was investigated by visual assays. Synergistic biofilm formation was evaluated by cocultures of P. micra and partner strains. Growth of planktonic cells was measured by evaluating the absorbance at OD660, and biofilm formation was examined by staining with crystal violet. The effects of soluble components on synergistic biofilm formation and planktonic cell growth were examined after coculture of P. micra and other strains separated with a 0.4-μm pore-size porous membrane. P. micra coaggregated with Fusobacterium nucleatum, Porphyromonas gingivalis, or Capnoctyophaga ochracea. P. micra showed no coaggregation with Staphylococcus aureus, S. epidermidis, or Prevotella intermedia. In mixed cultures, biofilm formation by P. micra and F. nucleatum was greater than that by P. micra and P. gingivalis or C. ochracea. In separated cocultures, planktonic cell growth of P. micra was enhanced by each of the three species. Biofilm formation by P. micra was enhanced by F. nucleatum and C. ochracea; however, no significant enhancement was observed with P. gingivalis. These data indicated that P. micra and F. nucleatum had synergistic effects in biofilm formation and that these effects may be important for colonization by these two species in apical periodontitis lesions.},
}
@article {pmid31520957,
year = {2019},
author = {Cheng, H and Cheng, D and Mao, J and Lu, T and Hong, PY},
title = {Identification and characterization of core sludge and biofilm microbiota in anaerobic membrane bioreactors.},
journal = {Environment international},
volume = {133},
number = {Pt A},
pages = {105165},
doi = {10.1016/j.envint.2019.105165},
pmid = {31520957},
issn = {1873-6750},
abstract = {An analysis of sludge (i.e., 63 samples) and biofilm (i.e., 79 samples) sampled from 13 anaerobic membrane bioreactors (AnMBR) was conducted. Predominant microbial community identification and multivariate analysis indicate that these reactors showed different microbial community structure, but these differences had no impact on the overall AnMBR performance. Instead, core microbial genera which occurred in ≥90% of sludge (20 genera) and biofilm (12 genera) samples could potentially account for the AnMBR performance. A further calculation on net growth rate (NGR) of core genera in sludge suggested distribution into two main groups (i.e., I: low relative abundance and NGR, II: high relative abundance or high NGR). Consistent positive correlations between bacterial genera were observed among those that exhibited either high relative abundance or high NGR. The anaerobic microbial consortium in both sludge and biofilm were largely affected by stochastic dispersal and migration processes (i.e., neutral assembly). However, Acinetobacter spp. and Methanobacterium spp. occurred consistently in higher frequency in the biofilm but in lower occurrence frequency in the AnMBR permeate. Findings from this study suggest first, specific core microorganisms exist in the sludge regardless of the operating conditions of the AnMBRs, and second, prevention of biofoulant layer on anaerobic membranes can be devised by minimizing attachment of microbes on surfaces in a non-selective manner.},
}
@article {pmid31520885,
year = {2019},
author = {Yuan, Z and Tao, B and He, Y and Mu, C and Liu, G and Zhang, J and Liao, Q and Liu, P and Cai, K},
title = {Remote eradication of biofilm on titanium implant via near-infrared light triggered photothermal/photodynamic therapy strategy.},
journal = {Biomaterials},
volume = {223},
number = {},
pages = {119479},
doi = {10.1016/j.biomaterials.2019.119479},
pmid = {31520885},
issn = {1878-5905},
abstract = {Biofilm formation is a main challenge in treatment of bone-implant-associated infections, resulting in tolerance to immune system and antibiotics. However, smart non-surgical or non-invasive treatment methods of combating established biofilm on an implant have been less reported. Herein, a therapeutic system consisting of mesoporous polydopamine nanoparticles (MPDA) to combat biofilm is reported for the first time. We develop a synergistic photothermal/photodynamic therapy (PTT/PDT) strategy aiming for biofilms eradication on titanium (Ti) implant, which is integrated with MPDA loading with photosensitizer Indocyanine Green (ICG) by π-π stacking. Specifically, MPDA is functionalized with RGD peptide to endow the modified Ti sample (Ti-M/I/RGD) with good cytocompatibility. More importantly, Ti-M/I/RGD implant remarkably kills Staphylococcus aureus (S. aureus) biofilm with an efficiency of 95.4% in vivo upon near infrared (NIR). After biofilm eradication, implant still displays great performance regarding osteogenesis and osseointegration. Overall, this study provides a PTT/PDT strtategy for the development of antibacterial Ti implants for potential orthpediac application.},
}
@article {pmid31519064,
year = {2019},
author = {Widiasih Widiyanto, T and Chen, X and Iwatani, S and Chibana, H and Kajiwara, S},
title = {Role of MFS transporter Qdr2p in biofilm formation by Candida glabrata.},
journal = {Mycoses},
volume = {},
number = {},
pages = {},
doi = {10.1111/myc.13005},
pmid = {31519064},
issn = {1439-0507},
abstract = {BACKGROUND: Candida glabrata represents the second-most frequent cause of candidiasis infections of the mucosa, bloodstream, and genito-urinary tract in immunocompromised individuals. The incidence of C. glabrata infection has increased significantly in the last two decades, mainly due to this species' abilities to resist various antifungal drugs and to form biofilms.<br><br>OBJECTIVES: We focused on the relationship between biofilm formation and the product of QDR2, a C. glabrata member of the Major Facilitator Superfamily (MFS) gene family, given that fungal biofilm formation limits drug penetration and is associated with persistent infection.<br><br>METHODS: The fungal cells in biofilms were compared between a C. glabrata ∆qdr2 mutant and its wild-type strain. Cells were analyzed for metabolism activity and drug susceptibility (using tetrazolium assay), adhesion activity, growth assay, and intracellular pH (using flow cytometry).<br><br>RESULTS: Compared to the wild-type, the C. glabrata ∆qdr2 showed lower adhesion activity and higher fluconazole susceptibility when assessed as a biofilm. The mutant also showed decreased metabolic activity during biofilm formation. Furthermore, the mutant grew more slowly under neutral-basic pH conditions. The qdr2 deletion in C. glabrata resulted in an impaired ability to maintain pH homeostasis, which led in turn to a reduction of cell growth and of adherence to an artificial matrix.<br><br>CONCLUSION: These results suggested that the Qdr2p function is needed for proper biofilm formation and biofilm maintenance in C. glabrata as well as biofilm drug resistance towards fluconazole. Qdr2p may play an important role in C. glabrata's ability to form biofilms on implanted medical devices in human bodies.},
}
@article {pmid31518800,
year = {2019},
author = {Iannacone, F and Di Capua, F and Granata, F and Gargano, R and Pirozzi, F and Esposito, G},
title = {Effect of carbon-to-nitrogen ratio on simultaneous nitrification denitrification and phosphorus removal in a microaerobic moving bed biofilm reactor.},
journal = {Journal of environmental management},
volume = {250},
number = {},
pages = {109518},
doi = {10.1016/j.jenvman.2019.109518},
pmid = {31518800},
issn = {1095-8630},
abstract = {In this study, long-term simultaneous nitrification denitrification (SND) and phosphorous removal were investigated in a continuous-flow microaerobic MBBR (mMBBR) operated at a dissolved oxygen (DO) concentration of 1.0 (±0.2) mg L-1. The mMBBR performance was evaluated at different feed carbon-to-nitrogen (C/N) ratios (2.7, 4.2 and 5.6) and HRTs (2 days and 1 day). Stable long-term mMBBR operation and chemical oxygen demand (COD), total inorganic nitrogen (TIN) and phosphorous (P-PO43-) removal efficiencies up to 100%, 68% and 72%, respectively, were observed at a feed C/N ratio of 4.2. Lower TIN removal efficiency and unstable performance were observed at feed C/N ratios of 2.7 and 5.6, respectively. HRT decrease from 2 days to 1 day resulted in transient NH4+ accumulation and higher NO2-/NO3- ratio in the effluent. Batch activity tests showed that biofilm cultivation at a feed C/N ratio of 4.2 resulted in the highest denitrifying activity (189 mg N gVSS-1 d-1), whereas the highest nitrifying activity (316 mg N gVSS-1 d-1) was observed after cultivation at a feed C/N ratio of 2.7. Thermodynamic modeling with Visual MINTEQ and stoichiometric evaluations revealed that P removal was mainly biological and can be attributed to the P-accumulating capacity of denitrifying bacteria.},
}
@article {pmid31518447,
year = {2019},
author = {Kettles, RA and Tschowri, N and Lyons, KJ and Sharma, P and Hengge, R and Webber, MA and Grainger, DC},
title = {The Escherichia coli MarA protein regulates the ycgZ-ymgABC operon to inhibit biofilm formation.},
journal = {Molecular microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mmi.14386},
pmid = {31518447},
issn = {1365-2958},
abstract = {The Escherichia coli marRAB operon is a paradigm for chromosomally encoded antibiotic resistance. The operon exerts its effect via an encoded transcription factor called MarA that modulates efflux pump and porin expression. In this work we show that MarA is also a regulator of biofilm formation. Control is mediated by binding of MarA to the intergenic region upstream of the ycgZ-ymgABC operon. The operon, known to influence the formation of curli fibres and colanic acid, is usually expressed during periods of starvation. Hence, the ycgZ-ymgABC promoter is recognised by σ38 (RpoS) associated RNA polymerase. We show that MarA does not influence σ38 dependent transcription. Instead, MarA drives transcription by the housekeeping σ70 associated RNA polymerase. The effects of MarA on ycgZ-ymgABC expression are coupled to biofilm formation by the rcsCDB phosphorelay system, with YcgZ, YmgA and YmgB forming a complex that directly interacts with the histidine kinase domain of RcsC.},
}
@article {pmid31516325,
year = {2019},
author = {Farrag, HA and Hosny, AEMS and Hawas, AM and Hagras, SAA and Helmy, OM},
title = {Potential efficacy of garlic lock therapy in combating biofilm and catheter-associated infections; experimental studies on an animal model with focus on toxicological aspects.},
journal = {Saudi pharmaceutical journal : SPJ : the official publication of the Saudi Pharmaceutical Society},
volume = {27},
number = {6},
pages = {830-840},
doi = {10.1016/j.jsps.2019.05.004},
pmid = {31516325},
issn = {1319-0164},
abstract = {Background: Life-threatening central venous catheter-related infections are primarily initiated by biofilm formation on the catheter surface. Antibiotic lock therapy is recommended for eradicating intraluminal biofilm. In the era of antibiotic resistance, antibiotics of natural origins provide an effective and cheap option for combating resistant strains. Garlic especially stole the spotlight because of its impressive antimicrobial effectiveness against such superbugs.<br><br>Aim: Is to estimate the potential use of fresh garlic extract (FGE) as a lock agent against multi-drug resistant (MDR) bacteria.<br><br>Methods: The agar well diffusion and broth microdilution techniques were employed to test the antimicrobial activities of FGE against five MDR strains; E. coli, Pseudomonas aeruginosa (P. aeruginosa), Klebsiella pneumoniae (K. pneumoniae), Serratia marscens (S. marscens) and Methicillin-resistant Staphylococcus aureus (MRSA). Then the protective and therapeutic efficiencies of FGE against bacterial biofilms were in-vitro evaluated; at concentrations of 100, 75, 50 and 25%; in tissue culture plate (TCP) and on the polyurethane (PU) sheets using the crystal violet (CV) assay and colony-forming unit (CFU), respectively. Scanning electron microscopy (SEM) was also used to confirm eradication of biofilms on PU sheets. Finally, systemic and deep tissue infections by P. aeruginosa and MRSA were induced in mice that were then treated by FGE at either 100 or 200 mg/kg for seven days. Where the antibacterial activity was assessed by tissue and blood culturing at the end of the treatment period. Biochemical, hematological and histological parameters were also investigated.<br><br>Results: FGE exhibited potent in-vitro and in-vivo antibacterial and antibiofilm activities against MDR strains. It not only didn't exhibit toxicological effects at the hematological and the histological levels but also provided protective effects as demonstrated by the significant drop in the biochemical parameters.<br><br>Conclusion: FGE has the potential to be used as a prophylactic and/or therapeutic lock agent against biofilm-associated infections caused by MDR bacteria.},
}
@article {pmid31515923,
year = {2019},
author = {Røder, HL and Liu, W and Sørensen, SJ and Madsen, JS and Burmølle, M},
title = {Interspecies interactions reduce selection for a biofilm optimized variant in a four-species biofilm model.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.14802},
pmid = {31515923},
issn = {1462-2920},
abstract = {Multispecies biofilms are structured and spatially defined communities, where interspecies interactions impact assembly and functionality. Here we compared the spatial organization and growth of bacterial cells in differently composed biofilm communities over time to determine links between interspecies interactions and selection for biofilm phenotypes of individual species. An established model community consisting of Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus was used. It was found that interspecies interactions led to varying levels of selection for a new colony phenotype of X. retroflexus, depending on the presence/absence of other species. When M. oxydans was absent, X. retroflexus was not able to establish in the top layers of the biofilm, which led to selection for a hyper-matrix forming phenotype of X. retroflexus that successfully established in the biofilm top layers. No such phenotypic X. retroflexus variants were identified in the presence of M. oxydans. These findings indicate that interspecies interactions may lead to favourable localization of individual species in a multispecies biofilm and thereby reduce selection for competitive phenotypes. This article is protected by copyright. All rights reserved.},
}
@article {pmid31515192,
year = {2019},
author = {Kim, A and Jung, JH and Lee, YJ and Park, JW and Pyon, JK},
title = {Minimally invasive salvage of infected breast tissue expanders: A continuous closed irrigation technique based on surface biofilm disruption.},
journal = {Journal of plastic, reconstructive &amp; aesthetic surgery : JPRAS},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.bjps.2019.07.020},
pmid = {31515192},
issn = {1878-0539},
abstract = {BACKGROUND: Removal of the infected device has been the general treatment for device-associated infection in antibiotic failure. There have been anecdotal attempts to salvage infected medical devices by introducing a continuous closed irrigation system.<br><br>OBJECTIVE: This study examines whether continuous closed irrigation of an infected device is a successful alternative to removal in patients with recalcitrant device-associated infection.<br><br>METHODS: Patients who were diagnosed with recalcitrant periexpander infections during the course of expander-implant breast reconstruction from 2010 to 2018 were enrolled in a retrospective case-control study. Patients who failed antibiotics before 2017 underwent expander removal, but patients since 2017 underwent continuous closed irrigation of the infected expanders. Treatment details and clinical outcomes were compared. Rationale for expander irrigation was based on review of the current literature on biofilm research.<br><br>RESULTS: During the study period, 21 out of the 1176 patients were diagnosed with periexpander infection recalcitrant to antibiotic therapy. Among the 21 patients, 16 underwent expander removal and five underwent expander irrigation. Clinical outcomes were comparable in terms of resolution of infection signs. The irrigation group showed fewer patients who abandoned reconstruction after infection treatment (removal = 11/16, irrigation = 1/5). Literature review revealed that expander irrigation might have induced hydrodynamic disruption of the biofilm structure.<br><br>CONCLUSION: Expander irrigation was less invasive than removal and effective in suppressing severe recalcitrant periexpander infection. Continuous closed irrigation of infected expander devices may be a successful antibiofilm strategy in treating device-associated infections in select patients.},
}
@article {pmid31514534,
year = {2019},
author = {Braga, AS and Girotti, LD and de Melo Simas, LL and Pires, JG and Pelá, VT and Buzalaf, MAR and Magalhães, AC},
title = {Effect of commercial herbal toothpastes and mouth rinses on the prevention of enamel demineralization using a microcosm biofilm model.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-9},
doi = {10.1080/08927014.2019.1662897},
pmid = {31514534},
issn = {1029-2454},
abstract = {This work evaluated the effects of commercial toothpastes and mouth rinses containing natural/herbal agents on biofilm viability, extracellular polysaccharide (EPS) production and on enamel demineralization in vitro. Microcosm biofilm was produced on bovine enamel for 5 days and treated daily with: Orgânico natural® (toothpaste/mouth rinse), Boni Natural Menta &amp; Malaleuca® (toothpaste/mouth rinse), Propolis &amp; Myrrh® (toothpaste), Colgate Total 12 Clean Mint® (toothpaste, positive control), Malvatricin® Plus (mouth rinse), PerioGard® (mouth rinse, positive control) or PBS (negative control). Tom's Propolis &amp; Myrrh® and Colgate Total 12® toothpastes and Malvatricin® Plus and PerioGard® mouth rinses significantly reduced biofilm viability (p < 0.05). Only PerioGard® had significant effects on biofilm thickness and EPS. Despite the indication that Tom's Propolis &amp; Myrrh® significantly reduced lesion depth, only Colgate Total 12® significantly reduced mineral loss. Malvatricin® Plus significantly reduced mineral loss and lesion depth, as did PerioGard®. Some herbal products, Malvatricin® Plus and Tom's Propolis &amp; Myrrh®, showed anticaries effects.},
}
@article {pmid31514307,
year = {2019},
author = {Balázs, VL and Horváth, B and Kerekes, E and Ács, K and Kocsis, B and Varga, A and Böszörményi, A and Nagy, DU and Krisch, J and Széchenyi, A and Horváth, G},
title = {Anti-Haemophilus Activity of Selected Essential Oils Detected by TLC-Direct Bioautography and Biofilm Inhibition.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {18},
pages = {},
doi = {10.3390/molecules24183301},
pmid = {31514307},
issn = {1420-3049},
support = {NKFI 18 K 128217//NKFI (National Research, Development and Innovation Office)/ ; },
abstract = {Essential oils (EOs) are becoming increasingly popular in medical applications because of their antimicrobial effect. Direct bioautography (DB) combined with thin layer chromatography (TLC) is a screening method for the detection of antimicrobial compounds in plant extracts, for example, in EOs. Due to their lipophilic character, the common microbiological assays (etc. disk diffusion) could not provide reliable results. The aim of this study was the evaluation of antibacterial and anti-biofilm properties of the EO of cinnamon bark, clove, peppermint, thyme, and their main components against Haemophilus influenzae and H. parainfluenzae. Oil in water (O/W) type Pickering nano-emulsions stabilized with silica nanoparticles from each oil were prepared to increase their water-solubility. Samples with Tween80 surfactant and absolute ethanol were also used. Results showed that H. influenzae was more sensitive to the EOs than H. parainfluenzae (except for cinnamon bark oil). In thin layer chromatography-direct bioautography (TLC-DB) the ethanolic solutions of thyme oil presented the best activity against H. influenzae, while cinnamon oil was the most active against H. parainfluenzae. Pickering nano-emulsion of cinnamon oil inhibited the biofilm formation of H. parainfluenzae (76.35%) more efficiently than samples with Tween80 surfactant or absolute ethanol. In conclusion, Pickering nano-emulsion of EOs could inhibit the biofilm production effectively.},
}
@article {pmid31514119,
year = {2019},
author = {Zhang, Q and Yu, Z and Jin, S and Zhu, L and Liu, C and Zheng, H and Zhou, T and Liu, Y and Ruan, R},
title = {Lignocellulosic residue as bio-carrier for algal biofilm growth: Effects of carrier physicochemical proprieties and toxicity on algal biomass production and composition.},
journal = {Bioresource technology},
volume = {293},
number = {},
pages = {122091},
doi = {10.1016/j.biortech.2019.122091},
pmid = {31514119},
issn = {1873-2976},
abstract = {Five types of lignocellulosic materials were applied as the bio-carriers for low-cost algal biofilm cultivation of three algal strains. The effects of bio-carrier physicochemical properties and toxicity on algal cells growth and attachment were investigated. Rougher and hydrophilic bio-carrier could yield more algal biomass than smoother and hydrophobic bio-carrier. Pine sawdust (diameter: 0.420-0.595 mm) performed the best when cultured Diplosphaera sp. (9.61 g·m-2·day-1) biofilm. Meanwhile, bio-carriers could be leached by the culture medium during cultivation, and their energy conversion proprieties could be improved due to the reduced ash contents and the decreased crystallinities. In addition, Chlorella vulgaris growth tests indicated that pine sawdust (15.45%) leachate promoted cell growth, whereas rick husk (15.48%) and sugarcane bagasse (13.19%) leachate inhibited cell growth. And bio-carriers leachates also modified the chemical compositions (lipid, protein and carbohydrate) of algal cells and increased the corresponding saturated fatty acids methyl ester content (from 48.71 to 55.58-57.08%).},
}
@article {pmid31514099,
year = {2019},
author = {Wang, G and Liu, Y and Wu, M and Zong, W and Yi, X and Zhan, J and Liu, L and Zhou, H},
title = {Coupling the phenolic oxidation capacities of a bacterial consortium and in situ-generated manganese oxides in a moving bed biofilm reactor (MBBR).},
journal = {Water research},
volume = {166},
number = {},
pages = {115047},
doi = {10.1016/j.watres.2019.115047},
pmid = {31514099},
issn = {1879-2448},
abstract = {Phenolic wastewater containing phenol and 4-chlorophenol pose a risk to the environment and to human health. Treating them using chemical-biological coupling method is challenging. In this study, manganese oxidizing bacteria (MnOB) were enriched in moving bed biofilm reactor (MBBR) using synthetic phenol wastewater (800 mg L-1) to facilitate in situ production of biogenic manganese oxides (BioMnOx) after 90 days of operation. Then, 4-chlorophenol (4-CP) was added to the MBBR to simulate mixed phenolic wastewater. Comparing the MBBR (R1) without feeding Mn(II) and the MBBR with BioMnOx (R2) production, R2 exhibited robust phenol and 4-CP removal performance. 16S rRNA gene sequencing was employed to determine the microbial community. Subsequently, a batch experiment demonstrated that partly purified BioMnOx does not exhibits a capacity for phenol removal, but can efficiently remove 4-CP. Interestingly, 5-chloro-2-hydroxymuconic semialdehyde was found in the products of 4-CP degradation, which was the unique product of 4-CP degradation by catechol 2,3-dioxygenase (C23O). In both reactors, only catechol 1,2-dioxygenase (C12O) activity from microbes can be detected, indicating that the existence of BioMnOx provide an alternative pathway in addition to microbe driven 4-CP degradation. Overall, MBBR based MnOB enrichment under high phenol concentration was achieved, and 4-CP/phenol removal can be accelerated by in situ-formed BioMnOx. Considering the C23O-like activity of BioMnOx, our results suggest a new coupling strategy that involves nanomaterials and a microbial consortium.},
}
@article {pmid31513898,
year = {2019},
author = {Thiruvengadam, M and Venkidasamy, B and Karuppasamy, P and Subramanian, U},
title = {'Biofilm Clippers'- enzyme formulation for bovine mastitic biofilm therapy.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103740},
doi = {10.1016/j.micpath.2019.103740},
pmid = {31513898},
issn = {1096-1208},
abstract = {Mastitis is one of the most important diseases that are threatening modern dairy farms. Biofilms of mastitic teat canal have serious clinical implications because of colonized pathogens having the ability to construct an extracellular polymeric substance (EPS) with increased tolerance to antimicrobials leads to difficulty in eradicating the infection. In this study, we investigated the synergistic biofilm disruptive effect of a combination of carbohydrate hydrolases targeting extracellular polysaccharides of biofilm matrix and we termed it as 'Biofilm Clippers (BC)'. Our findings demonstrate that the BC formulation exhibits intense biofilm-disrupting activity against Staphylococcus aureus biofilms. The results of the study showed that BC enables activity equivalent to physiologically achievable concentrations in disrupting biofilms of S. aureus in vitro. The synergistic anti-biofilm activities of BC on S. aureus biofilms demonstrated that the biofilm matrix is predominant of complex polysaccharides. Further, the confocal microscopic analysis demonstrates that the BC formulation is highly effective compared to the single treatment of either of the enzymes in disrupting the biofilm. To the best of our knowledge, this is the first report on the synergistic anti-biofilm activity of a class of enzyme formulation against mastitic biofilm mass. Even though a small study showed a promising effect on mastitic teat canal, further extensive investigation on a large number of bovines for mastitis therapeutic potential of this BC-derived product is now warranted.},
}
@article {pmid31513491,
year = {2019},
author = {Roes, C and Calladine, L and Morris, C},
title = {Biofilm management using monofilament fibre debridement technology: outcomes and clinician and patient satisfaction.},
journal = {Journal of wound care},
volume = {28},
number = {9},
pages = {608-622},
doi = {10.12968/jowc.2019.28.9.608},
pmid = {31513491},
issn = {0969-0700},
abstract = {OBJECTIVE: Best practice in wound bed preparation and biofilm-based wound management includes debridement to create a clean wound bed and to assist in minimising the redevelopment of biofilm. Biofilm that is not removed inhibits healing and redevelops if not prevented from doing so with topical antimicrobial agents. Monofilament fibre debriding technology (MFDT) is used for effective and rapid mechanical debridement of loose material, slough and biofilm. The objective of this evaluation was to determine the clinical effect and consequential levels of health professional and patient satisfaction with the results of a biofilm pathway that included MFDT to achieve debridement.<br><br>METHODS: This non-comparative, open label evaluation was conducted in static and non-static wounds that required debridement. MFDT was used to debride in a two-week evaluation of a biofilm pathway. Wounds were debrided three times in week one and twice in week two. Each debridement was followed by treatment with an antimicrobial dressing. Other care included secondary dressings and compression delivered according to local practice, guidelines and formularies. After the clinical evaluation, health professionals were invited to complete an online survey of the clinical outcomes and their satisfaction with the biofilm pathway.<br><br>RESULTS: There were 706 health professionals who provided answers to the survey questions. Wound types evaluated were leg ulcers (67.4%), pressure ulcers (10%), dehisced surgical wounds (1.7%), diabetic foot ulcers (7.4%) and other wounds (13.4%). Of the wounds, 9% were reported as non-static despite the eligibility criteria. Not all wounds followed the pathway. The most frequently-used antimicrobial was silver. Non-antimicrobial products used included all-in-one dressings, other secondary dressings and compression. There was a change in 77% of wounds overall after two weeks. Change was reported almost equally for both static and non-static wounds. Health professionals who did or did not follow the pathway were 'completely satisfied' or 'satisfied' with the overall clinical outcome 96% and 95%, respectively. Of the patients, 77% were 'completely satisfied' or 'satisfied' with healing after following the pathway, as reported by the treating health professional.<br><br>CONCLUSION: The biofilm pathway that includes MFDT appears effective. Wounds managed on the pathway were debrided effectively and healing progressed to the satisfaction of both health professionals and patients.},
}
@article {pmid31512521,
year = {2019},
author = {Jiang, X and Yan, X and Gu, S and Yang, Y and Zhao, L and He, X and Chen, H and Ge, J and Liu, D},
title = {Biosurfactants of Lactobacillus helveticus for biodiversity inhibit the biofilm formation of Staphylococcus aureus and cell invasion.},
journal = {Future microbiology},
volume = {14},
number = {},
pages = {1133-1146},
doi = {10.2217/fmb-2018-0354},
pmid = {31512521},
issn = {1746-0921},
abstract = {Aim: This study aimed to evaluate the differences of biosurfactants produced by two Lactobacillus helveticus strains against the biofilm formation of Staphylococcus aureus in vitro and in vivo. Materials &amp; methods: Scanning electron microscopy, Real time-quantitative PCR (RT-qPCR) and cell assay were used to analyze the inhibiting effect of biosurfactants against biofilm formation. Results &amp; conclusion: Results showed that the biosurfactants have anti-adhesive and inhibiting effects on biofilm formation in vivo and in vitro. The biofilm-formative genes and autoinducer-2 signaling regulated these characteristics, and the biosurfactant L. helveticus 27170 is better than that of 27058. Host cell adhesion and invasion results indicated that the biosurfactants L. helveticus prevented the S. aureus invading the host cell, which may be a new strategy to eliminate biofilms.},
}
@article {pmid31511592,
year = {2019},
author = {Lu, H and Que, Y and Wu, X and Guan, T and Guo, H},
title = {Metabolomics Deciphered Metabolic Reprogramming Required for Biofilm Formation.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {13160},
doi = {10.1038/s41598-019-49603-1},
pmid = {31511592},
issn = {2045-2322},
support = {2017YFC1308600, 2017YFC1308605//Ministry of Science and Technology of the People&amp;apos;s Republic of China (Chinese Ministry of Science and Technology)/ ; WF220441502//Shanghai Jiao Tong University (SJTU)/ ; 81274175, 31670031//National Natural Science Foundation of China (National Science Foundation of China)/ ; },
abstract = {Biofilm formation plays a key role in many bacteria causing infections, which mostly accounts for high-frequency infectious recurrence and antibiotics resistance. In this study, we sought to compare modified metabolism of biofilm and planktonic populations with UTI89, a predominant agent of urinary tract infection, by combining mass spectrometry based untargeted and targeted metabolomics methods, as well as cytological visualization, which enable us to identify the driven metabolites and associated metabolic pathways underlying biofilm formation. Surprisingly, our finding revealed distinct differences in both phenotypic morphology and metabolism between two patterns. Furthermore, we identified and characterized 38 differential metabolites and associated three metabolic pathways involving glycerolipid metabolism, amino acid metabolism and carbohydrate metabolism that were altered mostly during biofilm formation. This discovery in metabolic phenotyping permitted biofilm formation shall provide us a novel insight into the dissociation of biofilm, which enable to develop novel biofilm based treatments against pathogen causing infections, with lower antibiotic resistance.},
}
@article {pmid31510757,
year = {2019},
author = {Papadopoulou, D and Dabrowska, A and Harries, PG and Webb, JS and Allan, RN and Salib, RJ},
title = {Evaluation of a Bioengineered Honey and Its Synthetic Equivalent as Novel Staphylococcus aureus Biofilm-Targeted Topical Therapies in Chronic Rhinosinusitis.},
journal = {American journal of rhinology &amp; allergy},
volume = {},
number = {},
pages = {1945892419874700},
doi = {10.1177/1945892419874700},
pmid = {31510757},
issn = {1945-8932},
}
@article {pmid31508379,
year = {2019},
author = {Miao, X and Liu, H and Zheng, Y and Guo, D and Shi, C and Xu, Y and Xia, X},
title = {Inhibitory Effect of Thymoquinone on Listeria monocytogenes ATCC 19115 Biofilm Formation and Virulence Attributes Critical for Human Infection.},
journal = {Frontiers in cellular and infection microbiology},
volume = {9},
number = {},
pages = {304},
doi = {10.3389/fcimb.2019.00304},
pmid = {31508379},
issn = {2235-2988},
abstract = {This study aimed to determine the antimicrobial activity of thymoquinone (TQ) against Listeria monocytogenes, and to examine its inhibitory effects on biofilm formation, motility, hemolysin production, and attachment-invasion of host cells. The minimum inhibitory concentrations (MICs) of TQ against eight different L. monocytogenes strains ranged from 6.25-12.50 μg/mL. Crystal violet staining showed that TQ clearly reduced biofilm biomass at sub-MICs in a dose-dependent manner. Scanning electron microscopy suggested that TQ inhibited biofilm formation on glass slides and induced an apparent collapse of biofilm architecture. At sub-MICs, TQ effectively inhibited the motility of L. monocytogenes ATCC 19115, and significantly impacted adhesion to and invasion of human colon adenocarcinoma cells as well as the secretion of listeriolysin O. Supporting these findings, real-time quantitative polymerase chain reaction analysis revealed that TQ down-regulated the transcription of genes associated with motility, biofilm formation, hemolysin secretion, and attachment-invasion in host cells. Overall, these findings confirm that TQ has the potential to be used to combat L. monocytogenes infection.},
}
@article {pmid31508278,
year = {2019},
author = {Li, M and Li, L and Su, K and Liu, X and Zhang, T and Liang, Y and Jing, D and Yang, X and Zheng, D and Cui, Z and Li, Z and Zhu, S and Yeung, KWK and Zheng, Y and Wang, X and Wu, S},
title = {Highly Effective and Noninvasive Near-Infrared Eradication of a Staphylococcus aureus Biofilm on Implants by a Photoresponsive Coating within 20 Min.},
journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)},
volume = {6},
number = {17},
pages = {1900599},
doi = {10.1002/advs.201900599},
pmid = {31508278},
issn = {2198-3844},
abstract = {Biofilms have been related to the persistence of infections on medical implants, and these cannot be eradicated because of the resistance of biofilm structures. Therefore, a biocompatible phototherapeutic system is developed composed of MoS2, IR780 photosensitizer, and arginine-glycine-aspartic acid-cysteine (RGDC) to safely eradicate biofilms on titanium implants within 20 min. The magnetron-sputtered MoS2 film possesses excellent photothermal properties, and IR780 can produce reactive oxygen species (ROS) with the irradiation of near-infrared (NIR, λ = 700-1100 nm) light. Consequently, the combination of photothermal therapy (PTT) and photodynamic therapy (PDT), assisted by glutathione oxidation accelerated by NIR light, can provide synergistic and rapid killing of bacteria, i.e., 98.99 ± 0.42% eradication ratio against a Staphylococcus aureus biofilm in vivo within 20 min, which is much greater than that of PTT or PDT alone. With the assistance of ROS, the permeability of damaged bacterial membranes increases, and the damaged bacterial membranes become more sensitive to heat, thus accelerating the leakage of proteins from the bacteria. In addition, RGDC can provide excellent biosafety and osteoconductivity, which is confirmed by in vivo animal experiments.},
}
@article {pmid31507562,
year = {2019},
author = {Olsen, NMC and Røder, HL and Russel, J and Madsen, JS and Sørensen, SJ and Burmølle, M},
title = {Priority of Early Colonizers but No Effect on Cohabitants in a Synergistic Biofilm Community.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1949},
doi = {10.3389/fmicb.2019.01949},
pmid = {31507562},
issn = {1664-302X},
abstract = {The arrival order of different species to a habitat can strongly impact community assembly and succession dynamics, thus influencing functionality. In this study, we asked how prior colonization of one community member would influence the assembly of a synergistic multispecies biofilm community grown in vitro. We expected that the prior arrival would confer an advantage, in particular for good biofilm formers. Yet, we did not know if the cohabitants would be impaired or benefit from the pre-colonization of one member, depending on its ability to form biofilm. We used a consortium consisting of four soil bacteria; Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus. This consortium has been shown to act synergistically when grown together, thus increasing biofilm production. The results showed that the two good biofilm formers gained a fitness advantage (increase in abundance) when allowed prior colonization on an abiotic surface before the arrival of their cohabitants. Interestingly, the significantly higher number of the pre-colonized biofilm formers did not affect the resulting composition in the subsequent biofilm after 24 h.},
}
@article {pmid31507548,
year = {2019},
author = {Bisht, K and Wakeman, CA},
title = {Discovery and Therapeutic Targeting of Differentiated Biofilm Subpopulations.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1908},
doi = {10.3389/fmicb.2019.01908},
pmid = {31507548},
issn = {1664-302X},
abstract = {The association of microorganisms into biofilms produces functionally organized microbial structures that promote community survival in a wide range of environments. Much like when individual cells within a multicellular organism express different genes from the same DNA blueprint, individual microbial cells located within different regions of a biofilm structure can exhibit distinct genetic programs. These spatially defined regions of physiologically differentiated cells are reminiscent of the role of tissues in multicellular organisms, with specific subpopulations in the microbial community serving defined roles to promote the overall health of the biofilm. The functions of these subpopulations are quite diverse and can range from dormant cells that can withstand antibiotic onslaughts to cells actively producing extracellular polymeric substances providing integrity to the entire community. The purpose of this review is to discuss the diverse roles of subpopulations in the stability and function of clonal biofilms, the methods for studying these subpopulations, and the ways these subpopulations can potentially be exploited for therapeutic intervention.},
}
@article {pmid31505984,
year = {2019},
author = {Lee, JH and Kim, YG and Raorane, CJ and Ryu, SY and Shim, JJ and Lee, J},
title = {The anti-biofilm and anti-virulence activities of trans-resveratrol and oxyresveratrol against uropathogenic Escherichia coli.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-10},
doi = {10.1080/08927014.2019.1657418},
pmid = {31505984},
issn = {1029-2454},
abstract = {Uropathogenic Escherichia coli (UPEC) is the primary causative agent of urinary tract infections, which are one of the most common infectious disease types in humans. UPEC infections involve bacterial cell adhesion to bladder epithelial cells, and UPEC can also form biofilms on indwelling catheters that are often tolerant to common antibiotics. In this study, the anti-biofilm activities of t-stilbene, stilbestrol, t-resveratrol, oxyresveratrol, ε-viniferin, suffruticosol A, and vitisin A were investigated against UPEC. t-Resveratrol, oxyresveratrol, and ε-viniferin, suffruticosol A, and vitisin A significantly inhibited UPEC biofilm formation at subinhibitory concentrations (10-50 μg ml-1). These findings were supported by observations that t-resveratrol and oxyresveratrol reduced fimbriae production and the swarming motility in UPEC. Furthermore, t-resveratrol and oxyresveratrol markedly diminished the hemagglutinating ability of UPEC, and enhanced UPEC killing by human whole blood. The findings show that t-resveratrol, oxyresveratrol, and resveratrol oligomers warrant further attention as antivirulence strategies against persistent UPEC infections.},
}
@article {pmid31505413,
year = {2019},
author = {Cao, J and Wang, Q and Ma, T and Bao, K and Yu, X and Duan, Z and Shen, X and Li, C},
title = {Effect of EGCG-gelatin biofilm on the quality and microbial composition of tilapia fillets during chilled storage.},
journal = {Food chemistry},
volume = {305},
number = {},
pages = {125454},
doi = {10.1016/j.foodchem.2019.125454},
pmid = {31505413},
issn = {1873-7072},
abstract = {The effects of the (-)-Epigallocatechin gallate (EGCG)-gelatin biofilm treatment (EGT) on microbial composition and quality of tilapia fillets stored at low temperatures were evaluated. The changes in mechanical properties, microbial reproduction, as well as lipid and protein oxidation during fillets storage were determined. The results showed that EGT reduced the microbial count and the relative abundance of the fillets. And EGT delayed the rate of lipid oxidation and protein denaturation in fillets. Compared with the control group, EGT samples had lower K values (74% on 18 d) and biogenic amines (39 mg/kg for putrescine and 50 mg/kg for cadaverine on 21 d). According to sensory evaluation, the shelf life of tilapia fillets was extended by 6 d in the EGT group. Therefore, EGT improved the quality of cryopreserved tilapia fillets and could be considered as a potential method for fish fillet preservation.},
}
@article {pmid31505403,
year = {2019},
author = {Ren, L and McCuskey, SR and Moreland, A and Bazan, GC and Nguyen, TQ},
title = {Tuning Geobacter sulfurreducens biofilm with conjugated polyelectrolyte for increased performance in bioelectrochemical system.},
journal = {Biosensors &amp; bioelectronics},
volume = {144},
number = {},
pages = {111630},
doi = {10.1016/j.bios.2019.111630},
pmid = {31505403},
issn = {1873-4235},
abstract = {Bioelectrochemical systems (BESs) are emerging as a platform technology with great application potentials such as wastewater remediation and power generation. Materials for electrode/microorganism modification are being examined in order to improve the current production in BESs. Herein, we report that the current production increased almost one fold in single-chamber BES reactors, by adding a conjugated polyelectrolyte (CPE-K) in the growth medium to co-form the anodic biofilm with Geobacter sulfurreducens cells. The CPE-K treated BESs had a maximum current density as high as 12.3 ± 0.5 A/m2, with that of the controls being 6.2 ± 0.7 A/m2. Improved current production was sustained even after CPE-K was no longer added to the medium. It was demonstrated that increased current resulted from improvement of certain biofilm properties. Analysis using electrochemical impedance spectroscopy (EIS) showed that CPE-K addition decreased the charge transfer resistance at the cell/electrode interface and the diffusion resistance through the biofilm. Protein quantification showed increased biomass growth on the electrode surface, and confocal scanning microscopy images revealed enhanced biofilm permeability. These results demonstrated for the first time that conjugated polyelectrolytes could be used for G. sulfurreducens biofilm augmentation to achieve high electricity production through tuning the anodic biofilm in BESs.},
}
@article {pmid31505308,
year = {2019},
author = {Cui, YX and Biswal, BK and van Loosdrecht, MCM and Chen, GH and Wu, D},
title = {Long term performance and dynamics of microbial biofilm communities performing sulfur-oxidizing autotrophic denitrification in a moving-bed biofilm reactor.},
journal = {Water research},
volume = {166},
number = {},
pages = {115038},
doi = {10.1016/j.watres.2019.115038},
pmid = {31505308},
issn = {1879-2448},
abstract = {Sulfide-oxidizing autotrophic denitrification (SOAD) implemented in a moving-bed biofilm reactor (MBBR) is a promising alternative to conventional heterotrophic denitrification in mainstream biological nitrogen removal. The sulfide-oxidation intermediate - elemental sulfur - is crucial for the kinetic and microbial properties of the sulfur-oxidizing bacterial communities, but its role is yet to be studied in depth. Hence, to investigate the performance and microbial communities of the aforementioned new biosystem, we operated for a long term a laboratory-scale (700 d) SOAD MBBR to treat synthetic saline domestic sewage, with an increase of the surface loading rate from 8 to 50 mg N/(m2·h) achieved by shortening the hydraulic retention time from 12 h to 2 h. The specific reaction rates of the reactor were eventually increased up to 0.37 kg N/(m3·d) and 0.73 kg S/(m3·d) for nitrate reduction and sulfide oxidation with no significant sulfur elemental accumulation. Two sulfur-oxidizing bacterial (SOB) clades, Sox-independent SOB (SOBI) and Sox-dependent SOB (SOBII), were responsible for indirect two-step sulfur oxidation (S2-→S0→SO42-) and direct one-step sulfur oxidation (S2-→SO42-), respectively. The SOBII biomass-specific electron transfer capacity could be around 2.5 times greater than that of SOBI (38 mmol e-/(gSOBII·d) versus 15 mmol e-/(gSOBI·d)), possibly resulting in the selection of SOBII over SOBI under stress conditions (such as a shorter HRT). Further studies on the methods and mechanism of selecting of SOBII over SOBI in biofilm reactors are recommended. Overall, the findings shed light on the design and operation of MBBR-based SOAD processes for mainstream biological denitrification.},
}
@article {pmid31504755,
year = {2019},
author = {Juin, C and Perrin, F and Puy, T and Bernard, C and Mollichella, ML and Girardot, M and Costa, D and Guillard, J and Imbert, C},
title = {Anti-biofilm activity of a semi-synthetic molecule obtained from resveratrol against Candida albicans biofilm.},
journal = {Medical mycology},
volume = {},
number = {},
pages = {},
doi = {10.1093/mmy/myz087},
pmid = {31504755},
issn = {1460-2709},
abstract = {Candida albicans can form biofilm on tissues and medical devices, becoming, in that case, less susceptible to antifungal agents. Treatment of candidiasis associated with the formation of C. albicans biofilms is restricted to echinocandins and lipid forms of amphotericin B. This study investigated the activity of micafungin and resveratrol modified molecule (EB487) against C. albicans biofilms. The anti-biofilm growth (Bgrowth) and anti-preformed biofilm (Bpreformed) activities of micafungin (0 to 3.94 μM) and EB487 (0 to 20.32 mM) were comparatively studied separately and combined, using XTT, flow cytometry and cell counts approaches. Concentrations causing 50% inhibition of the studied steps (IC50) were evaluated. When tested separately, IC50 Bgrowth was obtained for 4.8 mM and 0.13 μM of EB487 and micafungin respectively, and IC50 Bpreformed for 3.6 mM and 0.06 μM of EB487 and micafungin respectively. Micafungin used alone was not able to totally eradicate fungi. Micafungin combined with EB487 displayed synergistic activity (both anti-growth- and anti-preformed biofilm-activities). Optimal combination concentrations were EB487 (≤9.12 mM -strain ATCC 28367™ or ≤8.12 mM -strain CAI4-p), micafungin (≤0.05 μM for both) and caused a total eradication of fungi. Dose reduction indexes obtained using these concentrations were at least 9 (micafungin) and 3.2 (EB487) for both anti-biofilm growth- and anti-preformed biofilm-activities. Combinations indexes were consistently below one, demonstrating a synergistic relationship between micafungin and EB487 in these conditions. This study demonstrated the strong anti-biofilm activity of EB487 and highlighted its synergistic potential when combined with micafungin. EB487 is a promising semi-synthetic molecule with prophylactic and curative interests in fighting C. albicans biofilms.},
}
@article {pmid31503362,
year = {2019},
author = {Chan, WY and Hickey, EE and Page, SW and Trott, DJ and Hill, PB},
title = {Biofilm production by pathogens associated with canine otitis externa, and the antibiofilm activity of ionophores and antimicrobial adjuvants.},
journal = {Journal of veterinary pharmacology and therapeutics},
volume = {},
number = {},
pages = {},
doi = {10.1111/jvp.12811},
pmid = {31503362},
issn = {1365-2885},
support = {LP130100736//ARC Linkage Grant/ ; //Ministry of Higher Education/ ; //Universiti Putra Malaysia/ ; },
abstract = {Otitis externa (OE) is a frequently reported disorder in dogs associated with secondary infections by Staphylococcus, Pseudomonas and yeast pathogens. The presence of biofilms may play an important role in the resistance of otic pathogens to antimicrobial agents. Biofilm production of twenty Staphylococcus pseudintermedius and twenty Pseudomonas aeruginosa canine otic isolates was determined quantitatively using a microtiter plate assay, and each isolate was classified as a strong, moderate, weak or nonbiofilm producer. Minimum biofilm eradication concentration (MBEC) of two ionophores (narasin and monensin) and three adjuvants (N-acetylcysteine (NAC), Tris-EDTA and disodium EDTA) were investigated spectrophotometrically (OD570nm) and quantitatively (CFU/ml) against selected Staphylococcus and Pseudomonas biofilm cultures. Concurrently, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of planktonic cultures were assessed. 16/20 of the S. pseudintermedius clinical isolates were weak biofilm producers. 19/20 P. aeruginosa clinical isolates produced biofilms and were distributed almost equally as weak, moderate and strong biofilm producers. While significant antibiofilm activity was observed, no MBEC was achieved with narasin or monensin. The MBEC for NAC ranged from 5,000-10,000 µg/ml and from 20,000-80,000 µg/ml against S. pseudintermedius and P. aeruginosa, respectively. Tris-EDTA eradicated P. aeruginosa biofilms at concentrations ranging from 6,000/1,900 to 12,000/3,800 µg/ml. The MBEC was up to 16-fold and eightfold higher than the MIC/MBC of NAC and Tris-EDTA, respectively. Disodium EDTA reduced biofilm growth of both strains at concentrations of 470 µg/ml and higher. It can be concluded that biofilm production is common in pathogens associated with canine OE. NAC and Tris-EDTA are effective antibiofilm agents in vitro that could be considered for the treatment of biofilm-associated OE in dogs.},
}
@article {pmid31502909,
year = {2019},
author = {Silva, MD and Sillankorva, S},
title = {Otitis media pathogens - A life entrapped in biofilm communities.},
journal = {Critical reviews in microbiology},
volume = {},
number = {},
pages = {1-18},
doi = {10.1080/1040841X.2019.1660616},
pmid = {31502909},
issn = {1549-7828},
abstract = {Otitis media is a group of inflammatory diseases of the middle ear with great impact on children worldwide. The most common reported bacterial pathogens are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Over the last years, the role of biofilms formed by otopathogens that contribute to otitis media recurrence and chronicity has been established. An improved understanding of the properties of biofilms formed by these bacteria, which factors influence them, and how these affect the host inflammatory response is important for the development of novel strategies for the treatment of otitis media. This review focuses on the biofilm nature that the most prevalent otopathogens adopt in otitis media infections. In addition, new treatment approaches targeting biofilms are highlighted.},
}
@article {pmid31502331,
year = {2019},
author = {Ayyash, M and Shehabi, A and Mahmoud, NN and Al Bakri, AG},
title = {Anti-Biofilm Properties of Triclosan with EDTA or Cranberry as Foley Catheter Lock Solutions.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14439},
pmid = {31502331},
issn = {1365-2672},
abstract = {AIMS: To investigate the efficiency of triclosan, ethylenediaminetetraacetic acid (EDTA) and cranberry alone or in combinations against Escherichia coli (E. coli) strains as urinary catheter lock solutions to reduce catheter associated urinary tract infections.<br><br>METHODS AND RESULTS: Viable counting was used to assess anti-biofilm activities for triclosan, EDTA and cranberry alone or in combinations against E. coli strains embedded in biofilm onto all-silicon Foley catheter surface. The results revealed that combination of triclosan (10 mg/mL/ EDTA (30 mg/mL) when filling the catheter balloon was able to eradicate and prevent biofilm formation among all tested E.coli including the resistant strains, while triclosan (8.5 mg/mL)/ cranberry (103 mg/mL) combination was a successful catheter lock solution by preventing all tested strains from adhering onto catheter surface when filled via the eye hole.<br><br>CONCLUSIONS: The combinations of triclosan/EDTA and triclosan/cranberry were significantly effective in eradicating and preventing biofilm formation of the tested E. coli strains on Foley catheters.<br><br>Combinations of triclosan/EDTA and triclosan/cranberry have a promising application as non-antibiotic catheter lock solution.},
}
@article {pmid31501280,
year = {2019},
author = {Stewart, PS and White, B and Boegli, L and Hamerly, T and Williamson, KS and Franklin, MJ and Bothner, B and James, GA and Fisher, S and Vital-Lopez, FG and Wallqvist, A},
title = {Conceptual Model of Biofilm Antibiotic Tolerance that Integrates Phenomena of Diffusion, Metabolism, Gene Expression, and Physiology.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00307-19},
pmid = {31501280},
issn = {1098-5530},
abstract = {Transcriptomic, metabolomic, physiological, and computational modeling approaches were integrated to gain insight into the mechanisms of antibiotic tolerance in an in vitro biofilm system. Pseudomonas aeruginosa biofilms were grown in drip-flow reactors on a medium composed to mimic the exudate from a chronic wound. After four days, the biofilm was 114 μm thick with 9.45 log10 cfu cm-2 These biofilms exhibited tolerance, relative to exponential-phase planktonic cells, to subsequent treatment with ciprofloxacin. The biofilm specific growth rate was estimated via elemental balances to be approximately 0.37 h-1 and with a reaction-diffusion model to be 0.32 h-1 or one-third of the planktonic maximum specific growth rate. Global analysis of gene expression indicated decreased transcription of ribosomal genes and other anabolic functions in biofilms compared to exponential-phase planktonic cells and revealed the induction of multiple stress responses in biofilm cells including those associated with growth arrest, zinc limitation, hypoxia, and acyl-homoserine lactone quorum sensing. Metabolic pathways for phenazine biosynthesis and denitrification were transcriptionally activated in biofilms. A customized reaction-diffusion model predicted that steep oxygen concentration gradients form when these biofilms are thicker than about 40 μm. Mutant strains that were deficient in Psl polysaccharide synthesis, stringent response, stationary phase response, and membrane stress response exhibited increased ciprofloxacin susceptibility when cultured in biofilms. These results support a sequence of phenomena leading to biofilm antibiotic tolerance involving oxygen limitation, electron acceptor starvation and growth arrest, induction of associated stress responses, and differentiation into protected cell states.IMPORTANCE Bacteria in biofilms are protected from killing by antibiotics and this reduced susceptibility contributes to the persistence of infections such as those in the cystic fibrosis lung and chronic wounds. A generalized conceptual model of biofilm antimicrobial tolerance with these mechanistic steps is proposed: 1) establishment of concentration gradients in metabolic substrates and products; 2) active biological responses to these changes in the local chemical microenvironment; 3) entry of biofilm cells into a spectrum of states involving alternative metabolisms, stress responses, slow growth, cessation of growth, or dormancy (all prior to antibiotic treatment); 4) adaptive responses to antibiotic exposure; and 5) reduced susceptibility of microbial cells to antimicrobial challenges in some of the physiological states accessed through these changes.},
}
@article {pmid31501144,
year = {2019},
author = {Richards, JP and Cai, W and Zill, NA and Zhang, W and Ojha, AK},
title = {Adaptation of Mycobacterium tuberculosis to biofilm growth is genetically linked to drug tolerance.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01213-19},
pmid = {31501144},
issn = {1098-6596},
abstract = {Mycobacterium tuberculosis (Mtb) spontaneously grows at the air-medium interface forming pellicle biofilms, which harbor more drug tolerant persisters than planktonic cultures. The underlying basis for increased persisters in Mtb biofilms is unknown. Using a Tn-seq approach, we show here that multiple genes that are necessary for fitness of Mtb cells within biofilms, but not in planktonic cultures, are also implicated in tolerance of bacilli to a diverse set of stressors and antibiotics. Thus, development of Mtb biofilms appears to be associated with an enrichment of population, in which challenging growth conditions within biofilm architecture select for cells that maintain intrinsic tolerance to exogenous stresses including antibiotic exposure. We further observed that the intrinsic drug tolerance of constituent cells of a biofilm determines the frequency of persisters. These findings together allow us to propose that the selection of elite cells during biofilm development promotes the frequency of persisters. Furthermore, probing the possibility that the population enrichment is an outcome of unique environment within biofilms, we demonstrate biofilm-specific induction in the synthesis of isonitrile lipopeptides (INLP). Mutation analysis indicates that INLP is necessary for the architecture development of Mtb biofilms. In summary, the study offers an insight into persistence of Mtb biofilms under antibiotic exposure, while identifying INLP as a potential biomarker for further investigation of this phenomenon.},
}
@article {pmid31500093,
year = {2019},
author = {Ratka, C and Weigl, P and Henrich, D and Koch, F and Schlee, M and Zipprich, H},
title = {The Effect of In Vitro Electrolytic Cleaning on Biofilm-Contaminated Implant Surfaces.},
journal = {Journal of clinical medicine},
volume = {8},
number = {9},
pages = {},
doi = {10.3390/jcm8091397},
pmid = {31500093},
issn = {2077-0383},
abstract = {PURPOSE: Bacterial biofilms are a major problem in the treatment of infected dental and orthopedic implants. The purpose of this study is to investigate the cleaning effect of an electrolytic approach (EC) compared to a powder-spray system (PSS) on titanium surfaces.<br><br>MATERIALS AND METHODS: The tested implants (different surfaces and alloys) were collated into six groups and treated ether with EC or PSS. After a mature biofilm was established, the implants were treated, immersed in a nutritional solution, and streaked on Columbia agar. Colony-forming units (CFUs) were counted after breeding and testing (EC), and control (PSS) groups were compared using a paired sample t-test.<br><br>RESULTS: No bacterial growth was observed in the EC groups. After thinning to 1:1,000,000, 258.1 ± 19.9 (group 2), 264.4 ± 36.5 (group 4), and 245.3 ± 40.7 (group 6) CFUs could be counted in the PSS groups. The difference between the electrolytic approach (test groups 1, 3, and 5) and PSS (control groups 2, 4, and 6) was statistically extremely significant (p-value < 2.2 × 10-16).<br><br>CONCLUSION: Only EC inactivated the bacterial biofilm, and PSS left reproducible bacteria behind. Within the limits of this in vitro test, clinical relevance could be demonstrated.},
}
@article {pmid31500048,
year = {2019},
author = {de Carvalho, FG and Magalhães, TC and Teixeira, NM and Gondim, BLC and Carlo, HL and Dos Santos, RL and de Oliveira, AR and Denadai, ÂML},
title = {Synthesis and characterization of TPP/chitosan nanoparticles: Colloidal mechanism of reaction and antifungal effect on C. albicans biofilm formation.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {104},
number = {},
pages = {109885},
doi = {10.1016/j.msec.2019.109885},
pmid = {31500048},
issn = {1873-0191},
abstract = {In the present study chitosan (Chit) nanoparticles were synthetized by the ionic gelation process, using tripolyphosphate (TPP) as crosslinking agent. The TPP/Chit nanoparticle formation was evaluated by titrations, measuring electrical conductivity (k), zeta potential (ZP), hydrodynamic diameter (Dh), viscosity (η) and heat by isothermal calorimetry (ITC). The antifungal effects were evaluated by C. albicans time-kill assays, inhibition of C. albicans initial adhesion and biofilm formation in comparison with nystatin and chitosan. Conductometric titration exhibited a typical precipitation profile, with an inflection at molar ratio of [TPP]/[Chitmon] ≈ 0.3, suggesting a 1:3.3 stoichiometry. The highest Dh, ZP and η values were shown at the beginning of titrations, due to the intramolecular repulsion between Chit-Chit. With addition of TPP, the values showed gradual reduction, with an intermediary transition at [TPP]/[Chitmon] ≈ 0.16, which was attributed to the partial breakdown of interchain crosslinking and formation of discrete charged aggregates. After this point, reaction should occur by neutralization of these assemblies, causing new reduction in values of Dh, ZP and η until [TPP]/[Chitmon] ≈ 0.3, when they reached their lowest values. ITC experiment also showed the occurrence of two bindings (K1 = 3.6 × 103 and K2 = 7.7 × 104), which were entropy driven. Biological results showed lower C. albicans viability for TPP/Chit over 24 h compared with chitosan and nystatin at MIC and 2 MIC. Moreover, TPP/Chit showed 25-50% inhibition of C. albicans adhesion and biofilm formation. The results showed that TPP/Chit nanoparticles reduced the initial adhesion and biofilm formation of C. albicans and demonstrated potential for use in a formulation for the treatment of oral candidiasis.},
}
@article {pmid31500022,
year = {2019},
author = {Jung, J and Li, L and Yeh, CK and Ren, X and Sun, Y},
title = {Amphiphilic quaternary ammonium chitosan/sodium alginate multilayer coatings kill fungal cells and inhibit fungal biofilm on dental biomaterials.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {104},
number = {},
pages = {109961},
doi = {10.1016/j.msec.2019.109961},
pmid = {31500022},
issn = {1873-0191},
abstract = {Formation of fungal biofilms on health care-related materials causes serious clinical consequences. This study reports a novel fungal repelling strategy to control fungal biofilm formation on denture biomaterials through layer-by-layer self-assembly (LBL). Amphiphilic quaternary ammonium chitosans (CS612) were synthesized and used as the antimicrobial positive layer, and sodium alginate (SA) was chosen as the negative layer to construct LBL multilayers on poly (methyl methacrylate) (PMMA)-based denture materials. The presence of LBL multilayers on denture disc was confirmed and characterized by surface zeta potential, water contact angle, AFM, and FT-IR analyses. The multilayer coatings, especially CS612 as the outmost layer, effectively prevented the fungal initial adhesion and biofilm formation. The Candida cells avoided the multilayer coatings and suspended in broth solution instead of forming biofilms, suggesting that the LBL multilayers had fungal repelling effects. The LBL multilayers were biocompatible toward mammalian cells. In stability tests, after immersion in PBS for 4 weeks under constant shaking and repeated brushing with a denture brush for up to 3000 times, the biofilm-controlling effects of the LBL multilayers were not affected, pointing to a novel long-term strategy in controlling fungal biofilms on denture and other related biomaterials.},
}
@article {pmid31499329,
year = {2019},
author = {Brück, HL and Delvigne, F and Dhulster, P and Jacques, P and Coutte, F},
title = {Molecular strategies for adapting Bacillus subtilis 168 biosurfactant production to biofilm cultivation mode.},
journal = {Bioresource technology},
volume = {293},
number = {},
pages = {122090},
doi = {10.1016/j.biortech.2019.122090},
pmid = {31499329},
issn = {1873-2976},
abstract = {Biofilm bioreactors have already been proven to be efficient systems for microbial lipopeptide production since they avoid foam formation. However, the cell adhesion capacities of the laboratory strain B.subtilis 168 to the biofilm bioreactor support are limited. In this work, we present a novel approach for increasing cell adhesion through the generation of filamentous and/or exopolysaccharide producing B.subtilis 168 mutants by genetic engineering. The single cell growth behavior was analyzed using time-lapse microscopy and the colonization capacities were investigated under continuous flow conditions in a drip-flow reactor. Cell adhesion could be increased three times through filamentous growth in lipopeptide producing B. subtilis 168 derivatives strains. Further restored exopolysaccharide production increased up to 50 times the cell adhesion capacities. Enhanced cell immobilization resulted in 10 times increased surfactin production. These findings will be of particular interest regarding the design of more efficient microbial cell factories for biofilm cultivation.},
}
@article {pmid31498302,
year = {2019},
author = {Depetris, A and Wiedmer, A and Wagner, M and Schäfer, S and Battin, TJ and Peter, H},
title = {Automated 3D Optical Coherence Tomography to Elucidate Biofilm Morphogenesis Over Large Spatial Scales.},
journal = {Journal of visualized experiments : JoVE},
volume = {},
number = {150},
pages = {},
doi = {10.3791/59356},
pmid = {31498302},
issn = {1940-087X},
abstract = {Biofilms are a most successful microbial lifestyle and prevail in a multitude of environmental and engineered settings. Understanding biofilm morphogenesis, that is the structural diversification of biofilms during community assembly, represents a remarkable challenge across spatial and temporal scales. Here, we present an automated biofilm imaging system based on optical coherence tomography (OCT). OCT is an emerging imaging technique in biofilm research. However, the amount of data that currently can be acquired and processed hampers the statistical inference of large scale patterns in biofilm morphology. The automated OCT imaging system allows covering large spatial and extended temporal scales of biofilm growth. It combines a commercially available OCT system with a robotic positioning platform and a suite of software solutions to control the positioning of the OCT scanning probe, as well as the acquisition and processing of 3D biofilm imaging datasets. This setup allows the in situ and non-invasive automated monitoring of biofilm development and may be further developed to couple OCT imaging with macrophotography and microsensor profiling.},
}
@article {pmid31497539,
year = {2019},
author = {Singh, VK and Mishra, A and Jha, B},
title = {Corrigendum: Anti-quorum Sensing and Anti-biofilm Activity of Delftia tsuruhatensis Extract by Attenuating the Quorum Sensing-Controlled Virulence Factor Production in Pseudomonas aeruginosa.},
journal = {Frontiers in cellular and infection microbiology},
volume = {9},
number = {},
pages = {308},
doi = {10.3389/fcimb.2019.00308},
pmid = {31497539},
issn = {2235-2988},
abstract = {[This corrects the article DOI: 10.3389/fcimb.2017.00337.].},
}
@article {pmid31493577,
year = {2019},
author = {Zhu, L and Chen, T and Xu, L and Zhou, Z and Feng, W and Liu, Y and Chen, H},
title = {Effect and mechanism of quorum sensing on horizontal transfer of multidrug plasmid RP4 in BAC biofilm.},
journal = {The Science of the total environment},
volume = {698},
number = {},
pages = {134236},
doi = {10.1016/j.scitotenv.2019.134236},
pmid = {31493577},
issn = {1879-1026},
abstract = {The widespread emergence of antibiotic resistance genes (ARGs) in drinking water systems endangers human health, and may be exacerbated by their horizontal gene transfer (HGT) among microbiota. In our previous study, Quorum sensing (QS) molecules produced by bacteria from biological activated carbon (BAC) biofilms were demonstrated to influence the transfer efficiency of a model conjugative plasmid, here RP4. In this study, we further explored the effect and mechanism of QS on conjugation transfer. The results revealed that Acyl-homoserine lactones producing (AHL-producing) bacteria isolated from BAC biofilm play a role in the propagation of ARGs. We selected several quorum sensing inhibitors (QSIs) to study their effects on AHL-producing bacteria, including the formation of biofilm and the regulating effect on conjugation transfer. In addition, the possible molecular mechanisms for AHLs that promote conjugative transfer were attributable to enhancing the mRNA expression, which involved altered expressions of conjugation-related genes. We also found that QSIs could inhibit conjugative transfer by downregulating the conjugation-relevant genes. We believe that this is the first insightful exploration of the mechanism by which AHLs will facilitate and QSIs will inhibit the conjugative transfer of ARGs. These results provide creative insight into ARG pollution control that involves blocking QS during BAC treatment in drinking water systems.},
}
@article {pmid31493571,
year = {2019},
author = {Ngan, WY and Habimana, O},
title = {From farm-scale to lab-scale: The characterization of engineered irrigation water distribution system biofilm models using an artificial freshwater source.},
journal = {The Science of the total environment},
volume = {698},
number = {},
pages = {134025},
doi = {10.1016/j.scitotenv.2019.134025},
pmid = {31493571},
issn = {1879-1026},
abstract = {Contaminants in freshwater environments, as well as the associated negative impacts on agricultural produce, have emerged as a critical theme of the water-energy-food nexus affecting food safety and irrigation management. Agricultural produce exposed to irrigation with questionable freshwater can internalize and concentrate pollutants. However, the potential risks posed by the ubiquitous presence of biofilms within irrigation water distribution systems (IWDS) remains overlooked, even though such biofilms may harbor and spread pathogenic, chemical, and other environmental pollutants. Our limited knowledge about the role and functional attributes of IWDS biofilms can be blamed mostly to experimental challenges encountered during attempted studies of these biofilms in their natural environments. Hence, a laboratory-based experimental system designed to simulate a freshwater environment was combined with a biofilm reactor capable of recreating the piping environments in water distribution systems. This experimental system was then tested to assess the robustness and repeatability of experimental early-stage biofilms with respect to physical structure and microbial community, using state-of-the-art confocal microscopy and next-generation sequencing, respectively. The results demonstrated the suitability of this laboratory-based experimental system for studying the impacts of selected pollutants on irrigation water distribution systems.},
}
@article {pmid31493408,
year = {2019},
author = {Milton, ME and Draughn, GL and Bobay, BG and Stowe, SD and Olson, AL and Feldmann, EA and Thompson, RJ and Myers, KH and Santoro, MT and Kearns, DB and Cavanagh, J},
title = {The Solution Structures and Interaction of SinR and SinI: Elucidating the Mechanism of Action of the Master Regulator Switch for Biofilm Formation in Bacillus subtilis.},
journal = {Journal of molecular biology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jmb.2019.08.019},
pmid = {31493408},
issn = {1089-8638},
abstract = {Bacteria have developed numerous protection strategies to ensure survival in harsh environments, with perhaps the most robust method being the formation of a protective biofilm. In biofilms, bacterial cells are embedded within a matrix that is composed of a complex mixture of polysaccharides, proteins and DNA. The Gram-positive bacterium Bacillus subtilis has become a model organism for studying regulatory networks directing biofilm formation. The phenotypic transition from a planktonic to biofilm state is regulated by the activity of the transcriptional repressor, SinR, and its inactivation by its primary antagonist, SinI. In this work, we present the first full-length structural model of tetrameric SinR using a hybrid approach combining high-resolution solution NMR, chemical crosslinking, mass spectrometry, and molecular docking. We also present the solution NMR structure of the antagonist SinI dimer, and probe the mechanism behind the SinR-SinI interaction using a combination of biochemical and biophysical techniques. As a result of these findings, we propose that SinI utilizes a residue replacement mechanism to block SinR multimerization, resulting in diminished DNA binding and concomitant decreased repressor activity. Finally, we provide an evidence-based mechanism that confirms how disruption of the SinR tetramer by SinI regulates gene expression.},
}
@article {pmid31493142,
year = {2019},
author = {Memariani, H and Memariani, M and Ghasemian, A},
title = {An overview on anti-biofilm properties of quercetin against bacterial pathogens.},
journal = {World journal of microbiology &amp; biotechnology},
volume = {35},
number = {9},
pages = {143},
doi = {10.1007/s11274-019-2719-5},
pmid = {31493142},
issn = {1573-0972},
abstract = {Bacterial biofilms are multicellular aggregates enclosed in a self-created biopolymer matrix. Biofilm-producing bacteria have become a great public health problem worldwide because biofilms enable these microorganisms to evade several clearance mechanisms produced by host and synthetic sources. Over the past years, different flavonoids including quercetin have engrossed considerable interest among researchers owing to their potential anti-biofilm properties. To our knowledge, there is no review regarding effects of quercetin towards bacterial biofilms, prompting us to summarize experimental evidence on its anti-biofilm properties. Quercetin inhibits biofilm development by a diverse array of bacterial pathogens such as Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans, Escherichia coli, and Pseudomonas aeruginosa. Prevention of bacterial adhesion, suppression of quorum-sensing pathways, disruption or alteration of plasma membrane, inhibition of efflux pumps, and blocking nucleic acid synthesis have been documented as major anti-biofilm mechanisms of quercetin. Overall, anti-biofilm activity of quercetin can open up new horizons in a wide range of biomedical areas, from food industry to medicine.},
}
@article {pmid31492289,
year = {2020},
author = {Harpale, K and Jagtap, K and Bankar, A and Dhole, S and More, M},
title = {Synthesis, Characterization and Anti-Biofilm Efficacy of Polypyrrole-Zinc Oxide Composites.},
journal = {Journal of nanoscience and nanotechnology},
volume = {20},
number = {4},
pages = {2639-2644},
doi = {10.1166/jnn.2020.17367},
pmid = {31492289},
issn = {1533-4899},
abstract = {A nanocomposite of Polypyrrole (PPy) and zinc oxide (ZnO), termed as PPy-ZnO, was synthesized by two step route. In the first step, synthesis of PPy was carried out by chemical oxidative route. In the second step, the PPy-ZnO nanocomposite was synthesized under hydrothermal conditions. The as-synthesized PPy-ZnO nanocomposites were characterized using X-ray Diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infra-red (FTIR) and Ultra violetvisible (UV-vis) spectroscopy to reveal the phase, morphology, chemical and optical properties. The physical and chemical characterizations confirmed presence of both PPy and ZnO phases in the nanocomposite. In the present work, antimicrobial activity of the PPy-ZnO nanocomposite against human pathogen Y. lipolytica has been investigated. Attempts have been made to reveal the influence of PPy percentage on the antimicrobial activity. Interestingly, all PPy-ZnO nanocomposites, irrespective of PPy percentage, showed 90 to 95% inhibited growth of Yarrowia lipolytica. The results obtained herein imply the potential of PPy-ZnO biofilm in inhibiting the growth of Y. lipolytica and thus preventing infections caused due to Y. lipolytica in humans.},
}
@article {pmid31491442,
year = {2019},
author = {Goeres, DM and Walker, DK and Buckingham-Meyer, K and Lorenz, L and Summers, J and Fritz, B and Goveia, D and Dickerman, G and Schultz, J and Parker, AE},
title = {Development, standardization, and validation of a biofilm efficacy test: The single tube method.},
journal = {Journal of microbiological methods},
volume = {},
number = {},
pages = {105694},
doi = {10.1016/j.mimet.2019.105694},
pmid = {31491442},
issn = {1872-8359},
abstract = {Methods validated by a standard setting organization enable public, industry and regulatory stakeholders to make decisions on the acceptability of products, devices and processes. This is because standard methods are demonstrably reproducible when performed in different laboratories by different researchers, responsive to different products, and rugged when small (usually inadvertent) variations from the standard procedure occur. The Single Tube Method (ASTM E2871) is a standard method that measures the efficacy of antimicrobials against biofilm bacteria that has been shown to be reproducible, responsive and rugged. In support of the reproducibility assessment, a six-laboratory study was performed using three antimicrobials: a sodium hypochlorite, a phenolic and a quaternary/alcohol blend, each tested at low and high efficacy levels. The mean log reduction in viable bacteria in this study ranged from 2.32 to 4.58 and the associated reproducibility standard deviations ranged from 0.89 to 1.67. Independent follow-up testing showed that the method was rugged with respect to deviations in sonication duration and sonication power but slightly sensitive to sonicator reservoir degassing and tube location within the sonicator bath. It was also demonstrated that when a coupon was dropped into a test tube, bacteria can splash out of reach of the applied antimicrobials, resulting in substantial bias when estimating log reductions for the products tested. Bias can also result when testing products that hinder the harvesting of microbes from test surfaces. The culmination of this work provided recommended changes to the early version of the standard method E2871-13 (ASTM, 2013b) including use of splashguards and microscopy checks. These changes have been incorporated into a revised ASTM method E2871-19 (ASTM 2019) that is the basis for the first regulatory method (ATMP-MB-20) to substantiate &quot;kills biofilm&quot; claims for antimicrobials registered and sold in the US.},
}
@article {pmid31490650,
year = {2019},
author = {Wang, JH and Zhao, Y and Chen, XY and Yang, Y and Wang, W and Wu, C and Yang, B and Zhang, Z and Zhang, LW and Liu, Y and Du, X and Li, W and Qiu, L and Jiang, P and Mou, XZ and Li, YQ},
title = {pH-Switchable Antimicrobial Nanofiber Networks of Hydrogel Eradicate Biofilm and Rescue Stalled Healing in Chronic Wound.},
journal = {ACS nano},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsnano.9b05608},
pmid = {31490650},
issn = {1936-086X},
abstract = {Biofilm infections can induce chronic inflammation and stall normal orchestrated course of wound healing cascades. Herein pH-switchable antimicrobial hydrogel with nanofiber networks for biofilm eradication and rescuing stalled healing in chronic wound is reported based on the self-assembly of a designed octapeptide (IKFQFHFD) at neutral pH. This hydrogel is biocompatible and exhibits acidic pH (pathological environment of infected chronic wounds)-switchable broad-spectrum antimicrobial effect via a mechanism involving cell wall and membrane disruption. The antimicrobial activity of hydrogel is derived from its acidic pH-dependent nanofiber networks destabilization and activated release of IKFQFHFD which is antimicrobial only at acidic pH due to the antimicrobial peptides-like molecular structure. In addition, supramolecular nanofiber networks loaded with drugs of cypate (photothermal agent) and proline (procollagen component) are further developed. In vitro experiments show that loaded drugs exhibit acidic pH (pH ~5.5)-responsive release profiles, and synergistic biofilm eradication and subsequent healing cascades activation of cells proliferation is achieved based on the supramolecular nanofiber networks. Remarkably, the nanofiber networks of hydrogel enables in vivo complete healing of MRSA biofilm-infected wound in diabetic mice within 20 days, showing great potential as promising chronic wound dressings. The proposed synergistic strategy for eradicating biofilm and activating subsequent healing cascades may offer a powerful modality for the management of clinical chronic wounds.},
}
@article {pmid31489410,
year = {2019},
author = {Wang, J and Zhao, S and Ran, SJ and Sun, Z and Liang, JP},
title = {[In vitro study of antimicrobial efficacy of different irrigations on Enterococcus faecalis biofilm formation in root canal].},
journal = {Shanghai kou qiang yi xue = Shanghai journal of stomatology},
volume = {28},
number = {3},
pages = {246-250},
pmid = {31489410},
issn = {1006-7248},
abstract = {PURPOSE: To compare the antimicrobial effect of different irrigations on Enterococcus faecalis biofilms in extracted teeth and evaluate the antimicrobial activity of irrigating solutions residual against E. faecalis biofilms formation, in order to provide a better strategy for clinician.<br><br>METHODS: Extracted human premolar teeth with single root canal were clearly autoclaved. These teeth were contaminated with E. faecalis（ATCC33186） and incubated for 60 days. The samples were randomly assigned to 4 experimental groups. During biomechanical instrumentation, the root canal was irrigated with different irrigating agents. The bacteria samples were collected with sterile paper points before and after instrumentation to F2. Then, samples that had been instrumented and autoclaved again were randomly divided into 2 groups treated with normal saline and 1%NaOCl for 30 min. E. faecalis was used to contaminate these root canals. The bacteria samples were collected with sterile paper points after 2, 6, 24, 48 h. SPSS19.0 software package was used for statistical analysis.<br><br>RESULTS: Group using 1% NaOCI with ultrasound devices was significantly more effective than NS alone groups. 1% NaOCI groups showed a better residual activity than NS group.<br><br>CONCLUSIONS: NaOCl is still the most important irrigating solutions, and it could be a better choice after biomechanical instrumentation, because of its long time substantivity achieves residual antimicrobial activity. Ultrasound devices is recommended to coordinate with irrigation.},
}
@article {pmid31489127,
year = {2019},
author = {Abdullah, N and Al-Marzooq, F and Mohamad, S and Abd Rahman, N and Chi Ngo, H and Perera Samaranayake, L},
title = {Intraoral appliances for in situ oral biofilm growth: a systematic review.},
journal = {Journal of oral microbiology},
volume = {11},
number = {1},
pages = {1647757},
doi = {10.1080/20002297.2019.1647757},
pmid = {31489127},
issn = {2000-2297},
abstract = {Background: Oral biofilms are the root cause of major oral diseases. As in vitro biofilms are not representative of the intraoral milieu, various devices have been manufactured over the years to develop Appliance Grown Oral Biofilm (AGOB). Objective: To review various intraoral appliances used to develop AGOB for microbiological analysis, and to judge the optimal means for such analyses. Design: Four databases (PubMed, Science Direct, Scopus and Medline) were searched by two independent reviewers, and articles featuring the key words 'device' OR 'splint' OR 'appliance'; 'Oral biofilm' OR 'dental plaque'; 'in vivo' OR 'in situ'; 'Microbiology' OR 'Bacteria' OR 'microbiome'; were included. The standard Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) were adopted for data gathering. Results: Of the 517 articles which met the initial inclusion criteria, 24 were deemed eligible for review. The age of the AGOB, sampled at various intervals, ranged from 30 min to 28 days. The most commonly used microbiome analytical methods were fluorescence microscopy, total cell count using conventional, and molecular tools including Next Generation Sequencing (NGS) platforms. Conclusions: No uniformly superior method for collecting AGOB could be discerned. NGS platforms are preferable for AGOB analyses.},
}
@article {pmid31487498,
year = {2019},
author = {Sheraton, MV and Melnikov, VR and Sloot, PMA},
title = {Prediction and Quantification of Bacterial Biofilm Detachment Using Glazier-Graner-Hogeweg Method Based Model Simulations.},
journal = {Journal of theoretical biology},
volume = {},
number = {},
pages = {109994},
doi = {10.1016/j.jtbi.2019.109994},
pmid = {31487498},
issn = {1095-8541},
abstract = {Morphological changes in bacterial biofilm structures arise from the fluid-structure interactions between the biofilm and the surrounding fluid. Depending on the magnitude of the force acting on the structure, the bacteria rearrange to attain an equilibrium shape or get washed away by the moving fluid. Understanding the dynamics behind the evolution of such equilibrium or failed states can aid in development of tools for biofilm removal or eradication. We develop a Glazier-Graner-Hogeweg method-based model to explore the collective evolution of biofilm morphology arising from cell-cell and cell-fluid interactions. We show that low adherence and high motility of the cells leads to sloughing of biofilms. Also, streamers are found to form under laminar flow conditions in tightly packed biofilms. In mixed species biofilms, we found that a species with less cell-cell binding affinity gets eroded faster than its counterpart. Therefore, we hypothesize that in nature these less-adherent species should be present encapsulated within the biofilm structure to maximize their chances of survival.},
}
@article {pmid31487117,
year = {2019},
author = {Malone, M and Schwarzer, S and Radzieta, M and Jeffries, T and Walsh, A and Dickson, HG and Micali, G and Jensen, SO},
title = {Effect on total microbial load and community composition with two vs six-week topical Cadexomer Iodine for treating chronic biofilm infections in diabetic foot ulcers.},
journal = {International wound journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/iwj.13219},
pmid = {31487117},
issn = {1742-481X},
support = {//Smith and Nephew/ ; },
abstract = {This study compares two vs six weeks of topical antimicrobial therapy with Cadexomer Iodine in patients with diabetic foot ulcers (DFUs) complicated by chronic biofilm infections. Patients with non-healing DFUs with suspected chronic biofilm infections were eligible for enrolment. Patients were randomised to receive either two or six weeks of treatment with topical Cadexomer Iodine. Tissue biopsies from the ulcers were obtained pre-and-post treatment and underwent DNA sequencing and real-time quantitative polymerase chain reaction (PCR) to determine the total microbial load, community composition, and diversity of bacteria. Scanning electron microscopy confirmed biofilm in all 18 ulcers with suspected chronic biofilm infections. Cadexomer Iodine resulted in 14 of 18 (78%) samples achieving a mean 0.5 log10 reduction in microbial load. Regardless of treatment duration, there was no statistical difference in the reduction of total microbial loads. No difference in the rate of wound healing in the two groups was seen at 6 weeks. Cadexomer Iodine reduces the total microbial load in DFUs with chronic biofilm infections and affects microbial community composition and diversity. All ulcers in both groups showed an initial reduction in wound size with application of Cadexomer Iodine, which might reflect its effect on biofilms.},
}
@article {pmid31485973,
year = {2019},
author = {Vergis, J and Malik, SVS and Pathak, R and Kumar, M and Sunitha, R and Barbuddhe, SB and Rawool, DB},
title = {Efficacy of Indolicidin, Cecropin A (1-7)-Melittin (CAMA) and Their Combination Against Biofilm-Forming Multidrug-Resistant Enteroaggregative Escherichia coli.},
journal = {Probiotics and antimicrobial proteins},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12602-019-09589-8},
pmid = {31485973},
issn = {1867-1314},
support = {CAAST-ACLH (NAHEP/CAAST/2018-19)//NAHEP programme of ICAR/ ; },
abstract = {The present study examined the anti-biofilm efficacy of two short-chain antimicrobial peptides (AMPs), namely, indolicidin and cecropin A (1-7)-melittin (CAMA) against biofilm-forming multidrug-resistant enteroaggregative Escherichia coli (MDR-EAEC) isolates. The typical EAEC isolates re-validated by PCR and confirmed using HEp-2 cell adherence assay was subjected to antibiotic susceptibility testing to confirm its MDR status. The biofilm-forming ability of MDR-EAEC isolates was assessed by Congo red binding, microtitre plate assays and hydrophobicity index; broth microdilution technique was employed to determine minimum inhibitory concentrations (MICs) and minimum biofilm eradication concentrations (MBECs). The obtained MIC and MBEC values for both AMPs were evaluated alone and in combination against MDR-EAEC biofilms using crystal violet (CV) staining and confocal microscopy-based live/dead cell quantification methods. All the three MDR-EAEC strains revealed weak to strong biofilm-forming ability and were found to be electron-donating and weakly electron-accepting (hydrophobicity index). Also, highly significant (P < 0.001) time-dependent hydrodynamic growth of the three MDR-EAEC strains was observed at 48 h of incubation in Dulbecco's modified Eagle's medium (DMEM) containing 0.45% D-glucose. AMPs and their combination were able to inhibit the initial biofilm formation at 24 h and 48 h as evidenced by CV staining and confocal quantification. Further, the application of AMPs (individually and combination) against the preformed MDR-EAEC biofilms resulted in highly significant eradication (P < 0.001) at 24 h post treatment. However, significant differences were not observed between AMP treatments (individually or in combination). The AMPs seem to be an effective candidates for further investigations such as safety, stability and appropriate biofilm-forming MDR-EAEC animal models.},
}
@article {pmid31485710,
year = {2019},
author = {Raouia, H and Hamida, B and Khadidja, A and Ahmed, L and Abdelwaheb, C},
title = {Effect of static magnetic field (200 mT) on biofilm formation in Pseudomonas aeruginosa.},
journal = {Archives of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00203-019-01719-8},
pmid = {31485710},
issn = {1432-072X},
abstract = {Several studies have investigated the effects of ionizing and non-ionizing radiations on microorganisms. However, the interaction between the magnetic field radiations and bacteria is less studied. The aim of our study was to study the effect of static magnetic field on the biofilm formation in Pseudomonas aeruginosa and its isogenic sod mutants. Our results revealed that the exposure to the static magnetic field (200 mT) increases significantly the swarming in the wild strain. The fliC gene expression did not show significant difference after 6 h exposure of the wild-type strain. The release of some compounds of the biofilm matrix such as rhamnolipids has been considerably enhanced after 6 h of exposure in the wild type. On the other hand, the pyocyanin and biofilm production was increased significantly in all strains compared to controls. Furthermore, our results revealed that the biofilm formation was confirmed by the pslA and ppyR gene expressions.},
}
@article {pmid31485510,
year = {2019},
author = {Hemdan, BA and El-Liethy, MA and ElMahdy, MEI and El-Taweel, GE},
title = {Metagenomics analysis of bacterial structure communities within natural biofilm.},
journal = {Heliyon},
volume = {5},
number = {8},
pages = {e02271},
doi = {10.1016/j.heliyon.2019.e02271},
pmid = {31485510},
issn = {2405-8440},
abstract = {The bacterial profiles of natural household biofilm have not been widely investigated. The majorities of these bacterial lineages are not cultivable. Thus, this study aims (i) to enumerate some potential bacterial lineages using culture based method within biofilm samples and confirmed using Biolog GEN III and polymerase chain reaction (PCR). (ii) To investigate the bacterial profiles of communities in two biofilm samples using next generation sequencing (NGS). Forty biofilm samples were cultured and colonies of each selected prevailing potential lineages (E. coli, Salmonella entrica, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes) were selected for confirmation. From obtained results, the counts of the tested bacterial lineages in kitchen biofilm samples were greater than those in bathroom samples. Precision of PCR was higher than Biolog GEN III to confirm the bacterial isolates. Using NGS analysis, the results revealed that a total of 110,554 operational taxonomic units (OTUs) were obtained for two biofilm samples, representing kitchen and bathroom biofilm samples. The numbers of phyla in the kitchen biofilm sample (35 OTUs) was higher than that in bathroom sample (18 OTUs). A total of 435 genera were observed in the bathroom biofilm sample compared to only 256 in the kitchen sample. Evidences have shown that the empirical gadgets for biofilm investigation are becoming convenient and affordable. Many distinct bacterial lineages observed in biofilm are one of the most significant issues that threaten human health and lead to disease outbreaks.},
}
@article {pmid31485170,
year = {2019},
author = {Al-Shabib, NA and Husain, FM and Khan, RA and Khan, MS and Alam, MZ and Ansari, FA and Laeeq, S and Zubair, M and Shahzad, SA and Khan, JM and Alsalme, A and Ahmad, I},
title = {Interference of phosphane copper (I) complexes of β-carboline with quorum sensing regulated virulence functions and biofilm in foodborne pathogenic bacteria: A first report.},
journal = {Saudi journal of biological sciences},
volume = {26},
number = {2},
pages = {308-316},
doi = {10.1016/j.sjbs.2018.04.013},
pmid = {31485170},
issn = {1319-562X},
abstract = {Foodborne pathogens are one of the major cause of food-related diseases and food poisoning. Bacterial biofilms and quorum sensing (QS) mechanism of cell-cell communication have also been found to be associated with several outbreaks of foodborne diseases and are great threat to food safety. Therefore, In the present study, we investigated the activity of three tetrahedrally coordinated copper(I) complexes against quorum sensing and biofilms of foodborne bacteria. All the three complexes demonstrated similar antimicrobial properties against the selected pathogens. Concentration below the MIC i.e. at sub-MICs all the three complexes interfered significantly with the quorum sensing regulated functions in C. violaceum (violacein), P. aeruginosa (elastase, pyocyanin and alginate production) and S. marcescens (prodigiosin). The complexes demonstrated potent broad-spectrum biofilm inhibition in Pseudomonas aeruginosa, E. coli, Chromobacterium violaceum, Serratia marcescens, Klebsiella pneumoniae and Listeria monocytogenes. Biofilm inhibition was visualized using SEM and CLSM images. Action of the copper(I) complexes on two key QS regulated functions contributing to biofilm formation i.e. EPS production and swarming motility was also studied and statistically significant reduction was recorded. These results could form the basis for development of safe anti-QS and anti-biofilm agents that can be utilized in the food industry as well as healthcare sector to prevent food-associated diseases.},
}
@article {pmid31484626,
year = {2019},
author = {Cusumano, JA and Caffrey, AR and Daffinee, KE and Luther, MK and Lopes, V and LaPlante, KL},
title = {Weak biofilm formation among carbapenem-resistant Klebsiella pneumoniae.},
journal = {Diagnostic microbiology and infectious disease},
volume = {},
number = {},
pages = {114877},
doi = {10.1016/j.diagmicrobio.2019.114877},
pmid = {31484626},
issn = {1879-0070},
abstract = {Biofilm formation of multidrug and extensively drug resistant Klebsiella pneumoniae isolates is poorly understood. We investigated 139 diverse clinical K. pneumoniae isolates that possess various resistance patterns to evaluate the relationship between biofilm formation and resistance. Antimicrobial resistance was compared among a diverse collection of weak versus strong biofilm-forming K. pneumoniae, and predictors of strong biofilm formation were identified. Multi-drug resistant isolates were more common among weak (97.9%) versus strong biofilm formers (76%; P = 0.002). Carbapenem-resistant K. pneumoniae were 91% less likely to form strong biofilm (odds ratio 0.09; 95% confidence interval 0.02-0.33). The statistically significant inverse relationship between biofilm formation and antibiotic resistance suggests that virulence may be a trade-off for survival.},
}
@article {pmid31484288,
year = {2019},
author = {Nilsson, M and Givskov, M and Twetman, S and Tolker-Nielsen, T},
title = {Inactivation of the pgmA Gene in Streptococcus mutans Significantly Decreases Biofilm-Associated Antimicrobial Tolerance.},
journal = {Microorganisms},
volume = {7},
number = {9},
pages = {},
doi = {10.3390/microorganisms7090310},
pmid = {31484288},
issn = {2076-2607},
support = {DFF - 1323-00177//Natur og Univers, Det Frie Forskningsråd/ ; 11/1596//Tandlægefonden/ ; },
abstract = {Screening of a Streptococcus mutans mutant library indicated that pgmA mutants displayed a reduced biofilm-associated tolerance toward gentamicin. The biofilms formed by the S. mutanspgmA mutant also displayed decreased tolerance towards linezolid and vancomycin compared to wild-type biofilms. On the contrary, the resistance of planktonic S. mutanspgmA cells to gentamycin, linezolid, and vancomycin was more similar to wild-type levels. Investigations of biofilms grown in microtiter trays and on submerged glass slides showed that pgmA mutants formed roughly the same amount of biofilm as the wild type, indicating that the reduced antimicrobial tolerance of these mutants is not due to diminished biofilm formation. The pgmA gene product is known to be involved in the synthesis of precursors for cell wall components such as teichoic acids and membrane glycolipids. Accordingly, the S. mutanspgmA mutant showed increased sensitivity to Congo Red, indicating that it has impaired cell wall integrity. A changed cell wall composition of the S. mutanspgmA mutant may play a role in the increased sensitivity of S. mutanspgmA biofilms toward antibiotics.},
}
@article {pmid31484093,
year = {2019},
author = {Zhang, M and Yu, M and Wang, Y and He, C and Pang, J and Wu, J},
title = {Operational optimization of a three-stage nitrification moving bed biofilm reactor (NMBBR) by obtaining enriched nitrifying bacteria: Nitrifying performance, microbial community, and kinetic parameters.},
journal = {The Science of the total environment},
volume = {697},
number = {},
pages = {134101},
doi = {10.1016/j.scitotenv.2019.134101},
pmid = {31484093},
issn = {1879-1026},
abstract = {A two-sludge system consisting of A2/O (Anaerobic Anoxic Oxic) and NMBBR (Nitrification Moving Bed Biofilm Reactor) was developed. Stable and efficient denitrifying phosphorus removal can be realized by high-efficiency utilization of carbon sources in A2/O reactor with the electron acceptors of NOx--N in a three-stage NMBBR (consisting of N1, N2, N3). The three-stage NMBBR was successfully started within 18 days without additional inoculation sludge. Then a long-term operation (22-120 d) for the optimization of nitrifying performance, microbial community, and kinetic parameters was investigated. The biofilm characteristics (MLSS and biofilm thickness) and real-time control parameters (DO and pH) initially revealed the differences of three stages, while FISH results confirmed the optimizing nitrifying bacteria populations including AOB, Nitrobacteria and Nitrospira (N1: 5.94 ± 0.12%; N2: 8.26 ± 0.42%; N3: 10.06 ± 0.27% on day 50), basically consisting with the qPCR results (N1: 4.05%; N2: 8.04%; N3: 14.14%). The specific ammonium oxidation rate (SAOR: 3.24-10.02 mg/(gMLSS·h)) and temperature coefficient (θ: 1.008-1.011) based on temperature variation (15-35 °C) exhibited a strong resistant ability to low temperature operation. Moreover, half-saturation constants (KN,AOB, KN,NOB, KO,AOB and KO,NOB) fitted by Monod equation proved that DO diffusion played a significant role than substrate utilization (NH4+-N and NO2--N), but the diffusion resistance was negligible for flocs size smaller than 70 μm. Additionally, the dominant NOB (mainly Nitrospira) due to a higher KN,NOB and KO,NOB was more sensitive to mass transfer and diffusion resistance, which was helpful to understand the microbial competition for short-cut nitrification between AOB and NOB. Based on the above mechanism analysis, the MBBR optimization for the design and operation was put forward.},
}
@article {pmid31483869,
year = {2019},
author = {Wu, M and Xu, L and Cai, Z and Huang, S and Li, Y and Lei, L and Huang, X},
title = {Disinfection of Cariogenic Pathogens in Planktonic Lifestyle, Biofilm, and Carious Dentine with Antimicrobial Photodynamic Therapy.},
journal = {Photochemistry and photobiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/php.13161},
pmid = {31483869},
issn = {1751-1097},
abstract = {Antimicrobial photodynamic therapy (aPDT) has been recommended for clinical application. Its antibacterial effect on bacteria remained in dentinal tubule was seldom investigated. Here we evaluated the antibacterial effects of aPDT on Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus) in planktonic lifestyle, biofilm, and carious dentine. Mono-species biofilms or dentinal caries formed on human dentine slices or slabs. Bacterial suspension, biofilms, and dentine caries were treated with 0.1 mg/mL Toluidine Blue O followed by irradiation with a light emission diode (λ - 635±10 nm; 500 mW; 31.5 J/cm2 ; 60s) and 0.12% chlorhexidine (CHX), respectively. Residual bacteria were determined by microbial culture analysis and scanning electron microscopy. One-way analysis of variance (ANOVA) was performed to detect the significance of the variables. Both treatments significantly reduced the number of L. acidophilus in planktonic state, biofilm, and carious dentine (p < 0.05). For S. mutans, CHX was only bactericidal against suspension (p < 0.05) while aPDT was effective on both suspension and biofilm (p < 0.05) while not for dentin caries (p > 0.05). Under the experimental conditions assessed, aPDT could be an alternative disinfection method for superficial layer of caries cavity. Its disinfection on bacteria in dentinal tubule of deep layer was deficient. This article is protected by copyright. All rights reserved.},
}
@article {pmid31482327,
year = {2019},
author = {Bonsaglia, ECR and Latosinski, GS and Rossi, RS and Rossi, BF and Possebon, FS and Pantoja, JCF and Fernandes Júnior, A and Rall, VLM},
title = {Biofilm production under different atmospheres and growth media by Streptococcus agalactiae isolated from milk of cows with subclinical mastitis.},
journal = {Archives of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00203-019-01727-8},
pmid = {31482327},
issn = {1432-072X},
abstract = {Different methods to analyze Streptococcus agalactiae biofilm formation have been investigated, but standardized protocols have not been developed. We compared S. agalactiae biofilm production among different atmospheres and growth media. Biofilm formation was studied in 32 isolates from bovine mastitis cases grown in Tryptone Soy Broth (TSB), Todd Hewitt Broth (THB), Luria Bertani Broth (LB) and Brain Heart Infusion (BHI), under two atmospheres, aerobic and 5% CO2. Regardless of the culture medium, growth under 5% CO2 resulted in a greater proportion of biofilm formation (65.63%), as compared with aerobic conditions (39.84%). Regardless of the atmosphere, the chances of biofilm formation were greater for isolates grown in TSB, as compared with THB [Odds ratio (OR) = 3.02], BHI (OR = 4.57), or LB (OR = 10.20). Thus, we suggest the use of 5% CO2 atmosphere and TSB in biofilm formation assays by Group-B streptococci (GBS) isolated from intramammary infections.},
}
@article {pmid31482119,
year = {2019},
author = {Wu, J and Li, F and Hu, X and Lu, J and Sun, X and Gao, J and Ling, D},
title = {Responsive Assembly of Silver Nanoclusters with a Biofilm Locally Amplified Bactericidal Effect to Enhance Treatments against Multi-Drug-Resistant Bacterial Infections.},
journal = {ACS central science},
volume = {5},
number = {8},
pages = {1366-1376},
doi = {10.1021/acscentsci.9b00359},
pmid = {31482119},
issn = {2374-7943},
abstract = {Bacterial biofilms pose a major threat to public health because they are resistant to most current therapeutics. Conventional antibiotics exhibit limited penetration and weakened activity in the acidic microenvironment of a biofilm. Here, the development of biofilm-responsive nanoantibiotics (rAgNAs) composed of self-assembled silver nanoclusters and pH-sensitive charge reversal ligands, whose bactericidal activity can be selectively boosted in the biofilm microenvironment, is reported. Under neutral physiological conditions, the bactericidal activity of rAgNAs is self-quenched because the toxic silver ions' release is largely inhibited; however, upon entry into the acidic biofilm microenvironment, the rAgNAs not only exhibit charge reversal to facilitate local accumulation and retention but also disassemble into small silver nanoclusters, thus enabling deep penetration and accelerated silver ions release for dramatically amplified bactericidal activity. The superior antibiofilm activity of rAgNAs is demonstrated both in vitro and in vivo, and the mortality rate of mice with multi-drug-resistant biofilm-induced severe pyomyositis can be significantly reduced by rAgNAs treatment, indicating the immense potential of rAgNAs as highly efficient nanoscale antibacterial agents to combat resistant bacterial biofilm-associated infections.},
}
@article {pmid31482007,
year = {2019},
author = {Keshvardoust, P and Huron, VAA and Clemson, M and Constancias, F and Barraud, N and Rice, SA},
title = {Biofilm formation inhibition and dispersal of multi-species communities containing ammonia-oxidising bacteria.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {22},
doi = {10.1038/s41522-019-0095-4},
pmid = {31482007},
issn = {2055-5008},
abstract = {Despite considerable research, the biofilm-forming capabilities of Nitrosomonas europaea are poorly understood for both mono and mixed-species communities. This study combined biofilm assays and molecular techniques to demonstrate that N. europaea makes very little biofilm on its own, and relies on the activity of associated heterotrophic bacteria to establish a biofilm. However, N. europaea has a vital role in the proliferation of mixed-species communities under carbon-limited conditions, such as in drinking water distribution systems, through the provision of organic carbon via ammonia oxidation. Results show that the addition of nitrification inhibitors to mixed-species nitrifying cultures under carbon-limited conditions disrupted biofilm formation and caused the dispersal of pre-formed biofilms. This dispersal effect was not observed when an organic carbon source, glucose, was included in the medium. Interestingly, inhibition of nitrification activity of these mixed-species biofilms in the presence of added glucose resulted in increased total biofilm formation compared to controls without the addition of nitrification inhibitors, or with only glucose added. This suggests that active AOB partially suppress or limit the overall growth of the heterotrophic bacteria. The experimental model developed here provides evidence that ammonia-oxidising bacteria (AOB) are involved in both the formation and maintenance of multi-species biofilm communities. The results demonstrate that the activity of the AOB not only support the growth and biofilm formation of heterotrophic bacteria by providing organic carbon, but also restrict and limit total biomass in mixed community systems.},
}
@article {pmid31481437,
year = {2019},
author = {Ribera, A and Benavent, E and El-Haj, C and Gomez-Junyent, J and Tubau, F and Rigo-Bonnin, R and Ariza, J and Murillo, O},
title = {Comparative anti-biofilm efficacy of meropenem alone and in combination with colistinin an in vitro pharmacodynamic model by extended-spectrum beta-lactamase-producing Klebsiella pneumoniae.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01230-19},
pmid = {31481437},
issn = {1098-6596},
abstract = {We compared the efficacies of meropenem alone and in combination with colistin against two strains of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae, using an in vitro pharmacodynamic model that mimicked two different biofilm conditions. Meropenem in monotherapy achieved a remarkable efficacy (even a bactericidal effect) in all conditions, whereas colistin was almost inactive and resistance emerged. The addition of colistin to meropenem produced no relevant benefits in contrast with experiences with other microorganisms.},
}
@article {pmid31480443,
year = {2019},
author = {Gabe, V and Kacergius, T and Abu-Lafi, S and Zeidan, M and Abu-Farich, B and Austys, D and Masalha, M and Rayan, A},
title = {Suppressive Effects of Octyl Gallate on Streptococcus mutans Biofilm Formation, Acidogenicity, and Gene Expression.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {17},
pages = {},
doi = {10.3390/molecules24173170},
pmid = {31480443},
issn = {1420-3049},
abstract = {The accumulation of biofilm by Streptococcus mutans bacteria on hard tooth tissues leads to dental caries, which remains one of the most prevalent oral diseases. Hence, the development of new antibiofilm agents is of critical importance. The current study reports the results from testing the effectiveness of octyl gallate (C8-OG) against: (1) S. mutans biofilm formation on solid surfaces (polystyrene, glass), (2) acidogenicity, (3) and the expression of biofilm-related genes. The amount of biofilm formed by S. mutans bacteria was evaluated using the colorimetric method and optical profilometry. The pH of the biofilm growth medium was measured with microelectrode. A quantitative reverse transcription-polymerase chain reaction (RT-qPCR) was used to assess the expression of genes encoding glucan binding protein B (gbpB), glucosyltransferases B, -C, -D (gtfB, -C, -D), and the F-ATPase β subunit of the F1 protein (atpD). The results show that C8-OG significantly diminished biofilm formation by exposed S. mutans on solid surfaces and suppressed acidogenicity in a dose-dependent manner, compared to unexposed bacteria (p < 0.05). The C8-OG concentration of 100.24 µM inhibited S. mutans biofilm development on solid surfaces by 100% and prevented a decrease in pH levels by 99%. In addition, the RT-qPCR data demonstrate that the biofilm-producing bacteria treated with C8-OG underwent a significant reduction in gene expression in the case of the four genes under study (gbpB, gtfC, gtfD, and atpD), and there was a slight decrease in expression of the gtfB gene. However, C8-OG treatments did not produce significant expression change compared to the control for the planktonic cells, although there was a significant increase for the atpD gene. Therefore, C8-OG might be a potent antibiofilm and/or anticaries agent for oral formulations that aim to reduce the prevalence of dental caries.},
}
@article {pmid31479959,
year = {2019},
author = {Wu, Y and Cai, P and Jing, X and Niu, X and Ji, D and Ashry, NM and Gao, C and Huang, Q},
title = {Soil biofilm formation enhances microbial community diversity and metabolic activity.},
journal = {Environment international},
volume = {132},
number = {},
pages = {105116},
doi = {10.1016/j.envint.2019.105116},
pmid = {31479959},
issn = {1873-6750},
abstract = {Biofilms have been extensively studied in aquatic and clinical environments. However, the complexity of edaphic microenvironment hinders the advances toward understanding the environmental functionalities and ecological roles of soil biofilms. In this work, artificial soil was employed to investigate the soil biofilm formation and corresponding impacts on community structure and microbial activities. Our results showed that extracellular polymeric substances (EPS) production was significantly enhanced and micro-meter sized cell aggregates formed with high glucose amendment. Biofilm development exhibited significant effects on the soil microbial processes. 16S rRNA gene sequencing demonstrated the soils with biofilms and free-living cells shared similar microbial communities. But the Shannon diversity and evenness indices of communities with soil biofilms were significantly enhanced by 18.2% and 17.1%. The soil with biofilms also revealed a rapid response to nutrient provision and robust microbial activity, which consumed 65.4% more oxygen in the topsoil (0-1.5 mm). Kinetic respiration analysis showed that the enhanced metabolic activity was attributed to 23-times more active microbes in soil biofilms. In summary, this study revealed that soil biofilms can sustain a diverse and robust community to drive soil biogeochemical processes.},
}
@article {pmid31478651,
year = {2019},
author = {Dunsing, V and Irmscher, T and Barbirz, S and Chiantia, S},
title = {A purely polysaccharide-based biofilm matrix provides size-selective diffusion barriers for nanoparticles and bacteriophages.},
journal = {Biomacromolecules},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.biomac.9b00938},
pmid = {31478651},
issn = {1526-4602},
abstract = {Biofilms are complex mixtures of proteins, DNA and polysaccharides surrounding bacterial communities as protective barriers that can be biochemically modified during the bacterial life cycle. However, their compositional heterogeneity impedes a precise analysis of the contributions of individual matrix components to the biofilm structural organization. To investigate the structural properties of glycan-based biofilms, we analyzed the diffusion dynamics of nanometer-sized objects in matrices of the megadalton-sized anionic polysaccharide stewartan, the major biofilm component of the plant pathogen Pantoea stewartii. Fluorescence correlation spectroscopy and single particle tracking of nano-beads and bacteriophages indicated notable sub-diffusive dynamics dependent on probe size and stewartan concentration, in contrast to free diffusion of small molecules. Stewartan enzymatic depolymerization by bacteriophage tailspike proteins rapidly restored unhindered diffusion. We thus hypothesize that the glycan polymer stewartan determines major physico-chemical properties of the biofilm, which acts as a selective diffusion barrier for nanometer-sized objects and can be controlled by enzymes.},
}
@article {pmid31476321,
year = {2019},
author = {Tao, S and He, L and Xu, HHK and Weir, MD and Fan, M and Yu, Z and Zhang, M and Zhou, X and Liang, K and Li, J},
title = {Dentin remineralization via adhesive containing amorphous calcium phosphate nanoparticles in a biofilm-challenged environment.},
journal = {Journal of dentistry},
volume = {},
number = {},
pages = {103193},
doi = {10.1016/j.jdent.2019.103193},
pmid = {31476321},
issn = {1879-176X},
abstract = {OBJECTIVES: The remineralization of dentin at a bonded interface would help to strengthen the bonded interface and inhibit secondary caries, and would prolong the longevity of restoration. The aim of this study was to investigate the remineralization of demineralized human dentin in a dental biofilm environment via an adhesive containing nanoparticles of amorphous calcium phosphate (NACP).<br><br>METHODS: Dentin demineralization was promoted by subjecting samples to a Streptococcus mutans acidic biofilm for 24 h. Samples were divided into a control group, a commercial fluoride-releasing adhesive group, and an NACP adhesive group. All samples were subjected to a remineralization protocol consisting of 4-h exposure per 24-h period in brain heart infusion broth plus 1% sucrose (BHIS) followed by immersion in artificial saliva for the remaining period. The pH of BHIS after 4-h immersion was measured every other day. After 10 days, the biofilm was assessed for colony-forming unit (CFU) count, lactic acid production, live/dead staining, and calcium and phosphate content. The mineral changes in the demineralized dentin samples were analyzed by transverse microradiography, hardness measurement, X-ray diffraction characterization, and scanning electron microscopy.<br><br>RESULTS: The NACP adhesive achieved acid neutralization, decreased biofilm CFU count, decreased biofilm lactic acid production, and increased biofilm calcium and phosphate content (P < 0.05). The NACP adhesive group had higher remineralization value than the commercial fluoride-releasing adhesive group (P < 0.05).<br><br>CONCLUSIONS: The NACP adhesive was effective in remineralizing dentin lesions in a biofilm model. Its ability to protect bond interface, inhibit secondary caries, and prolong the longevity of restoration is promising.<br><br>CLINICAL SIGNIFICANCE: Using NACP-containing adhesives could be recommended because of the protective ability of its hybrid layer even under a biofilm-challenged environment.},
}
@article {pmid31475567,
year = {2019},
author = {Cheng, P and Osei-Wusu, D and Zhou, C and Wang, Y and Xu, Z and Chang, T and Huo, S},
title = {The effects of refractory pollutants in swine wastewater on the growth of Scenedesmus sp. with biofilm attached culture.},
journal = {International journal of phytoremediation},
volume = {},
number = {},
pages = {1-10},
doi = {10.1080/15226514.2019.1658706},
pmid = {31475567},
issn = {1549-7879},
abstract = {Microalgae have been widely used for treatment of swine wastewater. However, the research on combined treatment of refractory pollutants ammonia nitrogen, Cu (II) and antibiotics from swine wastewater was still scattered. This study, the growth and removal efficiency of NH4Cl, CuSO4, tetracycline, norfloxacin and sulfadimidine with selected Scenedsmus sp. was investigated by biofilm attached culture. The results showed that low concentration of ammonia nitrogen had little effect on algae growth. The highest biomass productivity was 6.2 g/(m2d) at the concentration of NH4Cl of 50.0 mg/L, which was similar to that of a standard growth medium BG 11. Cu (II) concentration of 1.0 mg/L could accelerate the growth of Scenedsmus sp., and the highest biomass was 57.2 g/m2 in 8 days. Moreover, the highest biomass mean values was 59.5 g/m2, 57.1 g/m2, and 58.1 g/m2, respectively, when tetracycline concentration was 20.0 mg/L, norfloxacin concentration was 100.0 mg/L and sulfadimidine concentration was 10.0 mg/L. The removal efficiency of ammonia nitrogen, copper, tetracycline, norfloxacin and sulfadimidine with Scenedsmus sp. at their optimal initial concentration by biofilm attached culture was 85.2%, 64.6%, 74.6%,71.2%, and 62.3%, respectively. This study provides a theoretical basis for the purification of refractory substances from swine wastewater.},
}
@article {pmid31474100,
year = {2019},
author = {Aracri, FM and Cavalcanti, RM and Guimarães, LHS},
title = {Extracellular Tannase from Aspergillus ochraceus: Influence of the Culture Conditions on Biofilm Formation, Enzyme Production, and Application.},
journal = {Journal of microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.4014/jmb.1903.03060},
pmid = {31474100},
issn = {1738-8872},
abstract = {Aspergillus ochraceus biofilm, developed on an inert support, can produce tannase in Khanna medium containing 1.5% (w/v) tannic acid as the carbon source, at an initial pH of 5.0, for 72 h at 28 °C. Addition of 0.1% yeast extract increased enzyme production. The enzyme in the crude filtrate exhibited the highest activity at 30 °C and pH 6.0. At 50 °C, the half-life (T50) was 60 min and 260 min at pH 6.0. In general, addition of detergents and surfactants did not affect tannase activity significantly. Tannase has potential applications in various biotechnological processes such as the production of propyl gallate and in the treatment of tannin-rich effluents. The content of tannins and total phenolic compounds in effluents from leather treatment was reduced by 56-83% and 47-64%, respectively, after 2 h of enzyme treatment. The content of tannins and total phenolic compounds in the sorghum flour treated for 120 h with tannase were reduced by 61% and 17%, respectively. Interestingly, the same A. ochraceus biofilm was able to produce tannase for three sequential fermentative process. In conclusion, fungal biofilm is an interesting alternative to produce high levels of tannase with biotechnological potential to be applied in different industrial sectors.},
}
@article {pmid31472077,
year = {2019},
author = {Patry, B and Lessard, P and Vanrolleghem, PA},
title = {Nitrification in a biofilm-enhanced highly loaded aerated lagoon.},
journal = {Water environment research : a research publication of the Water Environment Federation},
volume = {},
number = {},
pages = {},
doi = {10.1002/wer.1234},
pmid = {31472077},
issn = {1554-7531},
abstract = {A full-scale biofilm-enhanced aerated lagoon using fixed submerged media was monitored using automated water quality monitoring stations over the span of one year to quantify its nitrification performance. The system was operating at a high organic loading rate averaging 5.8 g total CBOD5 /m2 of media per day (23.9 g total CBOD5 /m3 of lagoon per day), a total ammonia nitrogen loading rate averaging 0.9 g NH4 -N/m2 ∙d (3.7 g NH4 -N/m3 ∙d) and temperatures ranging from 1.6°C to 20.8°C. The system showed an extended seasonal nitrification period compared to a simulated aerated lagoon system of the same dimensions. This extension of complete nitrification with approximately 1 month was observed in the fall despite the decrease of operating temperature down to 4°C. During this maximum nitrification period, substantial denitrification occurred, and the effluent un-ionized ammonia ratio was reduced. A temporary loss of nitrification was also experienced in relation to an episode of elevated suspended solids concentration. Measured biofilm characteristics, namely the detachment dynamics and the biofilm thickness, were used to explain this temporary nitrification loss. During wintertime, a low nitrate production was still observed, suggesting year-long retention of nitrifying bacteria in the biofilm.},
}
@article {pmid31470914,
year = {2019},
author = {Nascimento, MM},
title = {Approaches to Modulate Biofilm Ecology.},
journal = {Dental clinics of North America},
volume = {63},
number = {4},
pages = {581-594},
doi = {10.1016/j.cden.2019.07.002},
pmid = {31470914},
issn = {1558-0512},
abstract = {Dental caries is closely related to a dysbiosis of the microbial consortia of supragingival oral biofilms driven by a sugar-frequent and acidic-pH environment. The pH is a key factor affecting the homeostasis of supragingival biofilms seen in health. There is increasing interest on the ecological dynamics of the oral microbiome and how a dysbiotic microbiota can be successfully replaced by health-beneficial flora. The concept of preventing the microbial dysbiosis related to caries through modulation of sugar intake and pH has fully emerged.},
}
@article {pmid31470085,
year = {2019},
author = {Sahal, G and Woerdenbag, HJ and Hinrichs, WLJ and Visser, A and Tepper, PG and Quax, WJ and van der Mei, HC and Bilkay, IS},
title = {Antifungal and biofilm inhibitory effect of Cymbopogon citratus (lemongrass) essential oil on biofilm forming by Candida tropicalis isolates; an in vitro study.},
journal = {Journal of ethnopharmacology},
volume = {},
number = {},
pages = {112188},
doi = {10.1016/j.jep.2019.112188},
pmid = {31470085},
issn = {1872-7573},
abstract = {Cymbopogon citratus (lemongrass) essential oil has been widely used as a traditional medicine and is well known for antimicrobial properties. Therefore, it might be a potent anti-infective and biofilm inhibitive against Candida tropicalis infections. Until now, no ideal coating or cleaning method based on an essential oil has been described to prevent biofilm formation of Candida strains on silicone rubber maxillofacial prostheses, voice prostheses and medical devices susceptible to C. tropicalis infections.<br><br>AIM OF THE STUDY: To investigate the antifungal and biofilm inhibitory effects of Cymbopogon citratus oil. Clinical isolates of C. tropicalis biofilms on different biomaterials were used to study the inhibitory effect.<br><br>MATERIALS AND METHODS: The efficacy of Cymbopogon citratus, Cuminum cyminum, Citrus limon and Cinnamomum verum essential oils were compared on biofilm formation of three C. tropicalis isolates on 24 well polystyrene plates. C. citratus oil coated silicone rubber surfaces were prepared using hypromellose ointment as a vehicle. The antifungal tests to determine minimum inhibitory and minimum fungicidal concentrations were assessed by a microbroth dilution method and biofilm formation was determined by a crystal violet binding assay.<br><br>RESULTS: C. tropicalis strains formed more biofilm on hydrophobic materials than on hydrophilic glass. C. citratus oil showed a high antifungal effect against all C. tropicalis strains. For comparison, C. limon oil and C. cyminum oil showed minor to no killing effect against the C. tropicalis strains. C. citratus oil had the lowest minimal inhibitory concentration of all essential oils tested and inhibited biofilm formation of all C. tropicalis strains. C. citratus oil coating on silicone rubber resulted in a 45-76% reduction in biofilm formation of all C. tropicalis strains.<br><br>CONCLUSION: Cymbopogon citratus oil has good potential to be used as an antifungal and antibiofilm agent on silicone rubber prostheses and medical devices on which C. tropicalis biofilms form a serious risk for skin infections and may cause a shorter lifespan of the prosthesis.},
}
@article {pmid31469956,
year = {2019},
author = {Zhu, C and Zhang, M and Tang, Q and Yang, Q and Li, J and He, X and Ye, Y},
title = {Structure and Activity of the Camellia Oleifera Sapogenin Derivatives on Growth and Biofilm Inhibition of Staphylococcus aureus and Escherichia coli.},
journal = {Journal of agricultural and food chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.jafc.9b03577},
pmid = {31469956},
issn = {1520-5118},
abstract = {Sapogenin is the main block of Camellia oleifera saponin, which was purified and structurally modified by C28 acylation reaction to synthesize 19 new derivatives. The growth and biofilm inhibition of Staphylococcus aureus and Escherichia coli was measured to evaluate their antibacterial effects. Three-dimensional quantitative structure-activity relationship (3D-QSAR) assay indicated that the antibacterial activities were significantly enhanced after the sapogenin was modified with aromatic ring or heterocyclic ring and electron-withdrawing substituents at the meta or para position. Among them the derivative of sapogenin with 2-mercapto-4-methyl -5-thiazolyl acetyl group obviously destroyed bacterial biofilm and made bacteria lysis. 3D-QSAR provides practical information for structural design of sapogenin derivatives with strong antibacterial activity, and the Camellia oleifera sapogenin derivative 28-O-(2-mercapto-4-methyl-5-thiazolyl)- 3β,16α,21β,22α-O- tetrahydroxy- oleantel- 2-Ene- 23-aldehyde (S-16) is an effective candidate of antibacterial agent for prevention of bacterial resistance against antibiotics.},
}
@article {pmid31469892,
year = {2019},
author = {Perov, S and Lidor, O and Salinas, N and Golan, N and Tayeb-Fligelman, E and Deshmukh, M and Willbold, D and Landau, M},
title = {Structural Insights into Curli CsgA Cross-β Fibril Architecture Inspire Repurposing of Anti-amyloid Compounds as Anti-biofilm Agents.},
journal = {PLoS pathogens},
volume = {15},
number = {8},
pages = {e1007978},
doi = {10.1371/journal.ppat.1007978},
pmid = {31469892},
issn = {1553-7374},
abstract = {Curli amyloid fibrils secreted by Enterobacteriaceae mediate host cell adhesion and contribute to biofilm formation, thereby promoting bacterial resistance to environmental stressors. Here, we present crystal structures of amyloid-forming segments from the major curli subunit, CsgA, revealing steric zipper fibrils of tightly mated β-sheets, demonstrating a structural link between curli and human pathological amyloids. D-enantiomeric peptides, originally developed to interfere with Alzheimer's disease-associated amyloid-β, inhibited CsgA fibrillation and reduced biofilm formation in Salmonella typhimurium. Moreover, as previously shown, CsgA fibrils cross-seeded fibrillation of amyloid-β, providing support for the proposed structural resemblance and potential for cross-species amyloid interactions. The presented findings provide structural insights into amyloidogenic regions important for curli formation, suggest a novel strategy for disrupting amyloid-structured biofilms, and hypothesize on the formation of self-propagating prion-like species originating from a microbial source that could influence neurodegenerative diseases.},
}
@article {pmid31469013,
year = {2019},
author = {Sidrim, JJ and Amando, BR and Gomes, FI and do Amaral, MS and de Sousa, PC and Ocadaque, CJ and Brilhante, RS and A Cordeiro, R and Rocha, MF and Scm Castelo-Branco, D},
title = {Chlorpromazine-impregnated catheters as a potential strategy to control biofilm-associated urinary tract infections.},
journal = {Future microbiology},
volume = {14},
number = {},
pages = {1023-1034},
doi = {10.2217/fmb-2019-0092},
pmid = {31469013},
issn = {1746-0921},
abstract = {Aim: This study proposes the impregnation of Foley catheters with chlorpromazine (CPZ) to control biofilm formation by Escherichia coli, Proteus mirabilis and Klebsiella pneumoniae. Materials &amp; methods: The minimum inhibitory concentrations (MICs) for CPZ and the effect of CPZ on biofilm formation were assessed. Afterward, biofilm formation and the effect of ciprofloxacin and meropenem (at MIC) on mature biofilms grown on CPZ-impregnated catheters were evaluated. Results: CPZ MIC range was 39.06-625 mg/l. CPZ significantly reduced (p < 0.05) biofilm formation in vitro and on impregnated catheters. In addition, CPZ-impregnation potentiated the antibiofilm activity of ciprofloxacin and meropenem. Conclusion: These findings bring perspectives for the use of CPZ as an adjuvant for preventing and treating catheter-associated urinary tract infections.},
}
@article {pmid31468360,
year = {2019},
author = {Cacaci, M and Martini, C and Cinzia, G and Torelli, R and Bugli, F and Sanguinetti, M},
title = {Graphene Oxide Coatings as Tools to Prevent Microbial Biofilm Formation on Medical Device.},
journal = {Advances in experimental medicine and biology},
volume = {},
number = {},
pages = {},
doi = {10.1007/5584_2019_434},
pmid = {31468360},
issn = {0065-2598},
abstract = {The clinical challenge on surface engineering of medical devices to prevent microorganisms adhesion and biofilm formation, has become an essential aspect for medical implants. Antibacterial properties of Graphene Oxide (GO) have been demonstrated across a broad spectrum of bacteria, and the different mechanisms of action with which this nanomaterial interacts with the microbial surface have been elucidated in detail. Innovative protective coatings based on graphene film and hydrogel could represent an innovative solution for the prevention of nosocomial pathogens colonization on implantable device. This brief review mainly focuses on the applications of graphene in nanomedicine with a particular deepening on the antibacterial properties of GO and GO-based nanomaterials. In order to evaluate the possible future applications of GO as an anti-biofilm coating material for medical devices, studies on the ability of graphene coated surface to prevent microbial adhesion are also discussed. A concise review on in vitro toxicity and in vivo safety is also presented.},
}
@article {pmid31468316,
year = {2019},
author = {Vuotto, C and Donelli, G},
title = {Novel Treatment Strategies for Biofilm-Based Infections.},
journal = {Drugs},
volume = {},
number = {},
pages = {},
doi = {10.1007/s40265-019-01184-z},
pmid = {31468316},
issn = {1179-1950},
abstract = {Biofilm-growing cells show an enhanced antimicrobial tolerance with respect to the same cells growing in a free-floating way. This is due to physical or chemical diffusion barriers and increased transfer of resistance markers. Thus, tissue- and medical device-related biofilms can be considered among the leading sources of antibiotic treatment failure, causing many of the deadliest chronic infections afflicting humans nowadays. To find a satisfying way to counteract this major health threat, a great effort has been made in recent years to develop safe, effective and fast-acting anti-biofilm strategies. In this review, we summarise and evaluate the most promising tools and molecules that have demonstrated their ability to modulate steps involved in biofilm formation or to disperse pre-formed biofilms, without conferring evolutionary pressure to microorganisms.},
}
@article {pmid31467861,
year = {2019},
author = {Heuschkel, I and Hoschek, A and Schmid, A and Bühler, B and Karande, R and Bühler, K},
title = {Mixed-trophies biofilm cultivation in capillary reactors.},
journal = {MethodsX},
volume = {6},
number = {},
pages = {1822-1831},
doi = {10.1016/j.mex.2019.07.021},
pmid = {31467861},
issn = {2215-0161},
abstract = {The biocatalytic application of photoautotrophic organisms is a promising alternative for the production of biofuels and value-added compounds as they do not rely on carbohydrates as a source of carbon, electrons, and energy. Although the photoautotrophic organisms hold potential for the development of sustainable processes, suitable reactor concepts that allow high cell density (HCD) cultivation of photoautotrophic microorganisms are limited. Such reactors need a high surface to volume ratio to enhance light availability. Furthermore, the accumulation of high oxygen concentrations as a consequence of oxygenic photosynthesis, and its inhibitory effect on cell growth needs to be prevented. Here, we present a method for HCD cultivation of oxygenic phototrophs based on the co-cultivation of different trophies in a biofilm format to avoid high oxygen partial-pressure and attain HCDs of up to 51.8 gBDW L-1 on a lab scale. In this article, we show: •A robust method for mixed trophies biofilm cultivation in capillary reactors•Set-up and operation of a biofilm capillary reactor•A method to quantify oxygen in the continuous biofilm capillary reactor.},
}
@article {pmid31467830,
year = {2019},
author = {Gozoua, E and Koffi-Nevry, R and Blache, Y},
title = {Biofilm formation in marine bacteria and biocidal sensitivity: interplay between a potent antibiofilm compound (AS162) and quorum-sensing autoinducers.},
journal = {3 Biotech},
volume = {9},
number = {9},
pages = {338},
doi = {10.1007/s13205-019-1866-6},
pmid = {31467830},
issn = {2190-572X},
abstract = {The capacity of two homoserine lactones to stimulate the marine bacteria Pseudoalteromonas ulvae (TC14 strain) for its capacity to form a biofilm when exposed to a potent antibiofilm compound AS162 is reported. Effective concentrations (EC50) of AS162 at 24 h, 48 h, and 72 h were, respectively, of 4.3, 4.4, and 6.0 µM. When tested in combination with HSLs, results showed that quorum-sensing signal molecules 3-oxo-C6 and 3-oxo-C8 homoserine lactones do not act directly on the biofilm formation, but are able to interfere positively with AS162 to promote biofilm growth with EC50 ranging from 30 to 50 µM. The same results were obtained with two other marine bacterial strains: Pseudoalteromonas lipolytica TC8 and Paracoccus sp. 4M6. These findings suggest that HSLs can significantly affect the biocidal sensitivity of marine bacteria to antifouling agents.},
}
@article {pmid31466323,
year = {2019},
author = {Senpuku, H and Nakamura, T and Iwabuchi, Y and Hirayama, S and Nakao, R and Ohnishi, M},
title = {Effects of Complex DNA and MVs with GTF Extracted from Streptococcus mutans on the Oral Biofilm.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {17},
pages = {},
doi = {10.3390/molecules24173131},
pmid = {31466323},
issn = {1420-3049},
support = {21390506, 24659821, 16K11537//Japan Society for the Promotion of Science/ ; 40105502//Japan Agency for Medical Research and Development/ ; },
abstract = {Streptococcus mutans is one of the principal pathogens for the development of dental caries. Oral biofilms formed by S. mutans are constructed of insoluble glucan formation induced by the principal enzymes, GTF-I and GTF-SI, in sucrose-containing conditions. However, as another means of biofilm formation, extracellular DNA (eDNA) and membrane vesicles (MVs) are also contributors. To explore the roles of eDNA and MVs for biofilm formation, short and whole size pure DNAs, two types of sub-purified DNAs and MVs were extracted from S. mutans by beads destruction, treatment of proteinase K, and ultracentrifugation of culture supernatant, and applied into the biofilm formation assay using the S. mutans UA159 gtfBC mutant, which lost GTF-I and GTF-SI, on a human saliva-coated 96 well microtiter plate in sucrose-containing conditions. Sub-purified DNAs after cell lysis by beads destruction for total 90 and 180 s showed a complex form of short-size DNA with various proteins and MVs associated with GTF-I and GTF-SI, and induced significantly higher biofilm formation of the S. mutans UA159.gtfBC mutant than no sample (p < 0.05). Short-size pure DNA without proteins induced biofilm formation but whole-size pure DNA did not. Moreover, the complex form of MV associated with GTFs and short-size DNA showed significantly higher biofilm formation of initial colonizers on the human tooth surface such as Streptococcus mitis than no sample (p < 0.05). The short-size DNAs associated with MVs and GTFs are important contributors to the biofilm formation and may be one of additional targets for the prevention of oral biofilm-associated diseases.},
}
@article {pmid31466002,
year = {2019},
author = {Herath, BS and Sathasivan, A},
title = {The chloramine stress induces the production of chloramine decaying proteins by microbes in biomass (biofilm).},
journal = {Chemosphere},
volume = {238},
number = {},
pages = {124526},
doi = {10.1016/j.chemosphere.2019.124526},
pmid = {31466002},
issn = {1879-1298},
abstract = {In this paper, for the first time, we show in chloraminated systems, the chloramine decaying proteins (CDP) play an important role in bulk water and biomass (biofilm) in resisting disinfectant. Extracellular polymeric substances in biofilm/biomass are known to protect microbes from disinfectants and toxic materials, but the exact mechanism(s) is/are not known. Starting with the seed from a nitrifying chloraminated reactor, two 5 L reactors were fed intermittently with either chloramine or ammonia containing nutrient solution. The degree of nitrification increased with time in both reactors despite an increase in soluble CDP in the chloraminated reactor, while soluble CDP decreased in the ammoniated one. The suspended biomass collected after eight months of operation from chloraminated reactor contained CDP and responded to short-term chloramine stress (1.5 h with initial 1.5 mg-Cl2·L-1) by the additional production of soluble CDP. The suspended biomass from ammoniated reactor neither contained CDP nor produced soluble CDP as a stress response. The production, release and accumulation of CDP in biomass (biofilm) could be one of several mechanisms microbes use to defend against disinfectants (stress). The new understanding will pave the way for better disinfection management and better design of experiments.},
}
@article {pmid31465921,
year = {2019},
author = {Fan, X and Peng, P and Huang, H and Peng, C and Gao, Y and Ren, H},
title = {Undesirable effects of exogenous N-acyl homoserine lactones on moving bed biofilm reactor treating medium-strength synthetic wastewater.},
journal = {The Science of the total environment},
volume = {696},
number = {},
pages = {134061},
doi = {10.1016/j.scitotenv.2019.134061},
pmid = {31465921},
issn = {1879-1026},
abstract = {Exogenous AHLs are gradually reported to facilitate biofilm growth, however, whether they play a universal role in promoting biofilm formation and pollutants removal remains to be investigated. The pollutant removal, biofilm properties, microbial community and the distribution of AHLs were investigated in three lab-scale MBBRs by continuous dosing 100 nM N-Hexanoyl-L-homoserine lactone (C6-HSL) and N-Octanoyl-L-homoserine lactone (C8-HSL) in synthetic wastewater under normal nutrition (40 mg/L NH4+-N with C/N = 20). Results showed that adding AHLs didn't affect organics removal and exogenous C6-HSL even significantly suppressed NH4+-N removal by 0.44-20.29% after 16 days (p < 0.05). The introduction of AHLs both facilitated biofilm growth and extracellular polymeric substances secretion while suppressed ATP production especially during the stable operation period, with 48.96% by C6-HSL (p < 0.05) and 27.25% by C8-HSL, respectively. Exogenous AHLs inhibited the proliferation of Chryseobacterium, resulting in improvement in biofilm growth and it probably mediated ATP synthesis through regulating the release of 3OHC12-HSL in aqueous phase. Organics removal and biofilm growth were mainly attributed to the combined actions of multitudinous AHLs in biofilm phase rather than that in aqueous phase. The counterintuitive conclusions obtained in this study highlighted the importance of legitimately applying exogenous AHLs to accelerate biofilm formation and the start-up of MBBR in wastewater treatment.},
}
@article {pmid31464096,
year = {2019},
author = {Hong, L and Liu, X and Tan, L and Cui, Z and Yang, X and Liang, Y and Li, Z and Zhu, S and Zheng, Y and Yeung, KWK and Jing, D and Zheng, D and Wang, X and Wu, S},
title = {Rapid Biofilm Elimination on Bone Implants Using Near-Infrared-Activated Inorganic Semiconductor Heterostructures.},
journal = {Advanced healthcare materials},
volume = {},
number = {},
pages = {e1900835},
doi = {10.1002/adhm.201900835},
pmid = {31464096},
issn = {2192-2659},
support = {51671081//NSFC/ ; 51871162//NSFC/ ; 51801056//NSFC/ ; 2016YFC1100600//National Key Research and Development Program of China/ ; 2016YFC1100604//National Key Research and Development Program of China/ ; 2018CFA064)//Natural Science Fund of Hubei Province/ ; },
abstract = {Bacterial infections often cause orthopedic surgery failures. It is hard for the immune system and antibiotics to clear bacteria adhered to implants after they form a mature biofilm, and a secondary surgery is required to remove the infected implants. To avoid this, a hybrid coating of Bi2 S3 @Ag3 PO4 /Ti is prepared to eliminate biofilm using near-infrared (NIR) light. Bi2 S3 nanorod (NR) arrays are prepared on titanium (Ti) implants through hydrothermal methods, and Ag3 PO4 nanoparticles (NPs) are loaded on Bi2 S3 NR arrays using a stepwise electrostatic adsorption strategy. The introduction of Ag3 PO4 NPs enhances the photocatalysis performances of Bi2 S3 , and the hybrid coating also exhibits good photothermal effects. After 808 nm light irradiation for 15 min, it shows superior bactericidal efficiency of 99.45% against Staphylococcus aureus, 99.74% against Escherichia coli in vitro, and 94.54% against S. aureus biofilm in vivo. Bi2 S3 @Ag3 PO4 /Ti also shows good cell viability compared to pure Ti. This NIR-activated-inorganic hybrid semiconductor heterojunction coating is biocompatible and could be employed to eliminate biofilm effectively, which makes it a very promising strategy for the surface modification of bone implant materials.},
}
@article {pmid31463386,
year = {2019},
author = {Gebreyohannes, G and Nyerere, A and Bii, C and Sbhatu, DB},
title = {Challenges of intervention, treatment, and antibiotic resistance of biofilm-forming microorganisms.},
journal = {Heliyon},
volume = {5},
number = {8},
pages = {e02192},
doi = {10.1016/j.heliyon.2019.e02192},
pmid = {31463386},
issn = {2405-8440},
abstract = {Background: Biofilms are multicellular communities of microorganisms held together by a self-produced extracellular matrix. The ability of microbes to form biofilm is a universal, ubiquitous, and dynamic process. This dynamic process of biofilms establishes an important strategy to withstand and survive harsh environmental conditions and antimicrobial agents.<br><br>Objective: This review paper aims to give an overview of antibiotic resistance, intervention, and treatment of infections caused by biofilm-forming organisms. Moreover, it can also help to motivate scholars to search for new anti-biofilm strategies and most appropriate methods to tackle the effect of biofilm infections on healthcare services.<br><br>Methods: This paper was written by reviewing recent research and review articles which are reporting about the antibiotic resistance, prevention, and treatment of biofilm-producing organisms.<br><br>Conclusion: Bioprospecting for quorum quenching compounds can be an appropriate solution for controlling biofilm infections.},
}
@article {pmid31461929,
year = {2019},
author = {Zhang, B and Zhuang, X and Guo, L and McLean, RJC and Chu, W},
title = {Recombinant N-acyl homoserine lactone-Lactonase AiiAQSI-1 Attenuates Aeromonas hydrophila Virulence Factors, Biofilm Formation and Reduces Mortality in Crucian Carp.},
journal = {Marine drugs},
volume = {17},
number = {9},
pages = {},
doi = {10.3390/md17090499},
pmid = {31461929},
issn = {1660-3397},
support = {31672676//National Natural Science Foundation of China/ ; PAPD//Priority Academic Program Development of Jiangsu Higher Education Institutions/ ; },
abstract = {Quorum quenching (QQ) is a promising alternative infection-control strategy to antibiotics that controls quorum-regulated virulence without killing the pathogens. Aeromonas hydrophila is an opportunistic gram-negative pathogen living in freshwater and marine environments. A. hydrophila possesses an N-acyl homoserine lactone (AHL)-based quorum-sensing (QS) system that regulates virulence, so quorum signal-inactivation (i.e., QQ) may represent a new way to combat A. hydrophila infection. In this study, an AHL lactonase gene, aiiA was cloned from Bacillus sp. strain QSI-1 and expressed in Escherichia coli strain BL21(DE3). The A. hydrophila hexanoyl homoserine lactone (C6-HSL) QS signal molecule was degraded by AiiAQSI-1, which resulted in a decrease of bacterial swimming motility, reduction of extracellular protease and hemolysin virulence factors, and inhibited the biofilm formation of A. hydrophila YJ-1 in a microtiter assay. In cell culture studies, AiiAQSI-1 decreased the ability of A. hydrophila adherence to and internalization by Epithelioma papulosum cyprini (EPC) cells. During in vivo studies, oral administration of AiiAQSI-1 via feed supplementation attenuated A. hydrophila infection in Crucian Carp. Results from this work indicate that feed supplementation with AiiAQSI-1 protein has potential to control A. hydrophila aquaculture disease via QQ.},
}
@article {pmid31459295,
year = {2018},
author = {Gupta, P and Gupta, S and Sharma, M and Kumar, N and Pruthi, V and Poluri, KM},
title = {Effectiveness of Phytoactive Molecules on Transcriptional Expression, Biofilm Matrix, and Cell Wall Components of Candida glabrata and Its Clinical Isolates.},
journal = {ACS omega},
volume = {3},
number = {9},
pages = {12201-12214},
doi = {10.1021/acsomega.8b01856},
pmid = {31459295},
issn = {2470-1343},
abstract = {Toxicity challenges by antifungal arsenals and emergence of multidrug resistance scenario has posed a serious threat to global community. To cope up with this alarming situation, phytoactive molecules are richest, safest, and most effective source of broad spectrum antimicrobial compounds. In the present investigation, six phytoactive molecules [cinnamaldehyde (CIN), epigallocatechin, vanillin, eugenol (EUG), furanone, and epigallocatechin gallate] were studied against Candida glabrata and its clinical isolates. Among these, CIN and EUG which are active components of cinnamon and clove essential oils, respectively, exhibited maximum inhibition against planktonic growth of C. glabrata at a concentration of 64 and 128 μg mL-1, respectively. These two molecules effectively inhibited and eradicated approximately 80% biofilm of C. glabrata and its clinical isolates from biomaterials. CIN and EUG increased reactive oxygen species generation, cell lysis, and ergosterol content in plasma membrane and reduced virulence attributes (phospholipase and proteinase) as well as catalase activity of C. glabrata cells. Reduction of mitochondrial membrane potential with increased release of cytochrome c from mitochondria to cytosol indicated initiation of early apoptosis in CIN- and EUG-treated C. glabrata cells. Transcriptional analysis showed that multidrug transporter (CDR1) and ergosterol biosynthesis genes were downregulated in the presence of CIN, while getting upregulated in EUG-treated cells. Interestingly, genes such as 1,3-β-glucan synthase (FKS1), GPI-anchored protein (KRE1), and sterol importer (AUS1) were downregulated upon treatment of CIN/EUG. These results provided molecular-level insights about the antifungal mechanism of CIN and EUG against C. glabrata including its resistant clinical isolate. The current data established that CIN and EUG can be potentially formulated in new antifungal strategies.},
}
@article {pmid31456753,
year = {2019},
author = {Zago, PMW and Dos Santos Castelo Branco, SJ and de Albuquerque Bogéa Fecury, L and Carvalho, LT and Rocha, CQ and Madeira, PLB and de Sousa, EM and de Siqueira, FSF and Paschoal, MAB and Diniz, RS and Gonçalves, LM},
title = {Anti-biofilm Action of Chenopodium ambrosioides Extract, Cytotoxic Potential and Effects on Acrylic Denture Surface.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1724},
doi = {10.3389/fmicb.2019.01724},
pmid = {31456753},
issn = {1664-302X},
abstract = {Considering the challenge to control Candida-associated denture stomatitis, the search for antifungal substances derived from natural sources has become a trend in the literature. In this study the following effects of Chenopodium ambrosioides extract (CAE) were investigated: action against biofilms of Candida albicans, its cytotoxic potential, and changes caused in acrylic resin. The CAE was characterized by High Performance Liquid Chromatography (HPLC). The susceptibility of C. albicans to CAE was investigated by Minimum Inhibitory Concentration and Minimum Fungicidal Concentration (MIC and MFC) tests. Acrylic resin disks were fabricated, and C. albicans biofilms were developed on these for 48 h. Afterward the disks were immersed for 10 min in: PBS (Negative Control); 1% Sodium Hypochlorite (1% SH, Positive Control) or CAE at MIC or 5xMIC. The biofilms were investigated relative to counts and metabolic activity. The cytotoxic potential in keratinocytes and fibroblasts was verified by MTT test. Change in color and roughness of the acrylic resin was analyzed after 28 days of immersion in CAE. The data were analyzed by the ANOVA considering a 5% level of significance. The main compounds detected by HPLC were kaempferol and quercetin. Both MIC and MFC obtained the value of 0.25 mg/mL. The MIC was sufficient to significantly reduce the counts and activity of the biofilm cells (p < 0.0001), while 5xMIC resulted in almost complete eradication, similar to 1% SH. Keratinocytes and fibroblasts exposed to the MIC and 5xMIC presented cell viability similar to that of the Control Group (p > 0.05). No important changes in acrylic resin color and roughness were detected, even after 28 days. It could be concluded that the immersion of acrylic resin in C. ambrosioides extract in its minimum inhibitory concentration was effective for the reduction of C. albicans biofilms without any evidence of cytotoxic effects or changes in roughness and color of this substrate.},
}
@article {pmid31456169,
year = {2019},
author = {Andre, C and de Jesus Pimentel-Filho, N and de Almeida Costa, PM and Vanetti, MCD},
title = {Changes in the composition and architecture of staphylococcal biofilm by nisin.},
journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]},
volume = {},
number = {},
pages = {},
doi = {10.1007/s42770-019-00135-w},
pmid = {31456169},
issn = {1678-4405},
support = {APQ 02600-14-1//FAPEMIG/ ; },
abstract = {Bacterial biofilms are involved in various medical infections and food contamination episodes and, for this reason, it is of great importance to developing new strategies of its prevention and control. The subinhibitory concentration of nisin was determined, and its effect against Staphylococcus aureus and Staphylococcus epidermidis biofilms was evaluated. Results obtained by confocal laser microscopy demonstrated morphological changes in the architecture of the structure of biofilms. The main components (polysaccharides, proteins, and extracellular DNA (eDNA)) of the biofilm matrix were determined by spectrophotometry and showed that the formation of staphylococcal biofilms in the presence of nisin results in a less dense matrix structure with modification in its constituents. These results contribute to increase the knowledge of the composition and architecture of the extracellular matrix of biofilms of S. aureus, as well as evidence that the investigation of alternative products to assist in the control and combat of biofilms is a promising strategy.},
}
@article {pmid31454730,
year = {2019},
author = {Zhou, H and Xu, G},
title = {Integrated effects of temperature and COD/N on an up-flow anaerobic filter-biological aerated filter: Performance, biofilm characteristics and microbial community.},
journal = {Bioresource technology},
volume = {293},
number = {},
pages = {122004},
doi = {10.1016/j.biortech.2019.122004},
pmid = {31454730},
issn = {1873-2976},
abstract = {The integrated effects of temperature and COD/N ratio on performance, biofilm characteristics and microbial community in up-flow anaerobic filter-biological aerated filters (UAF-BAFs) were investigated. Results indicated that the UAF-BAF system could achieve excellent COD, NH4+-N and TN removal, in which effluent quality well met the Class 1A standard. Biofilm physicochemical characteristics showed that the biomass, biofilm thickness and extracellular polymeric substance (EPS) content in the UAF-BAFs reduced with the decrease in COD/N ratio, but were enhanced under low temperature. The biofilm structure characterized by CLSM in the UAF-BAFs significantly shifted, which was closely correlated with operational conditions. Sequencing analysis revealed that Proteobacteria, Epsilonbacteraeota, Bacteroidetes and Firmicutes were dominant in the UAFs and the abundance of ammonium oxidizing bacteria (AOB) was responsible for nitrification performance in the BAFs. Functions analysis indicated that amino acid metabolism, carbohydrate metabolism, energy metabolism and lipid metabolism were clearly regulated by parameters changes.},
}
@article {pmid31454717,
year = {2019},
author = {Chen, LH and Li, Y and Qi, Y and Wang, SN and Gao, CQ and Wu, Y},
title = {Evaluation of a pulsed xenon ultraviolet light device for reduction of pathogens with biofilm-forming ability and impact on environmental bioburden in clinical laboratories.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.08.026},
pmid = {31454717},
issn = {1873-1597},
abstract = {BACKGROUND: Biofilm-forming organisms can persist on surfaces in hospital clinical laboratories and potentially lead to nosocomial infections. Therefore, effective decontamination procedures are essential for reducing infections. In this study, we investigated an alternative to often ineffective manual cleaning methods, a pulsed xenon ultraviolet (PX-UV) light device. We evaluated PX-UV effect on biofilm formation ability of pathogens and also evaluated PX-UV effectiveness on environmental bioburden in clinical laboratories.<br><br>METHODS: We selected and identified P. aeruginosa PA47, Staphylococcus aureus B1, and K. pnenumoniae CR52 from clinic isolates. Biofilm-forming ability and effectiveness of PX-UV in killing these biofilm forming strains on surfaces was evaluated. A body fluid testing laboratory, microbiology laboratory, and immunology/HIV prescreening laboratory were chosen for testing environmental bioburden. Air samples and high-touch surface specimens in the three laboratories were obtained before and after routine manual cleaning, and after 6 min of PX-UV disinfection. The cultured microbes were then identified with MALDI- TOF-MS.<br><br>RESULTS: We found that P. aeruginosa PA47, Staphylococcus aureus B1, and K. pnenumoniae CR52 were able to form robust biofilms, and that PX-UV significantly reduced colony counts of these strains on all surfaces tested. PX-UV reduced the bioburden of air samples and eliminated bioburden on surfaces. All microbes identified in the clinical laboratories were pathogenic and consisted of cocci, rods, and fungi.<br><br>CONCLUSIONS: The PX-UV device effectively reduced pathogens with biofilm-forming ability on surfaces, and the environmental bioburden was also significantly reduced by PX-UV. PX-UV is a viable option for protecting staff and decreasing rates of laboratory-acquired infections.},
}
@article {pmid31454558,
year = {2019},
author = {Prasath, KG and Sethupathy, S and Pandian, SK},
title = {Proteomic analysis uncovers the modulation of ergosterol, sphingolipid and oxidative stress pathway by myristic acid impeding biofilm and virulence in Candida albicans.},
journal = {Journal of proteomics},
volume = {208},
number = {},
pages = {103503},
doi = {10.1016/j.jprot.2019.103503},
pmid = {31454558},
issn = {1876-7737},
abstract = {Candida albicans, a dimorphic opportunistic fungus is known to form robust biofilm and commonly associated with superficial and life threatening systemic infections. The repertoire of C. albicans infection is comprehensive due to its biofilm mediated virulence and occurrence of resistance against conventional antifungal drugs. Natural bioactive compounds are known for their antivirulence potency against fungi circumventing their resistance. In the present study, antibiofilm and antihyphal efficacies of myristic acid (MA), a major component of Myristica fragrans against C. albicans was assessed. Results of biofilm assays, optical microscopic analyses showed the potent inhibition of biofilm and hyphal formation by MA at 125 μg mL-1. Proteomic analysis revealed the ability of MA to target proteins involved in various virulence pathways such as ergosterol synthesis, sphingolipid metabolism, multidrug resistance and the oxidative stress. The results of gene expression analysis and biochemical assays validated the outcomes of proteomic analysis. This investigation emphasized the potent antibiofilm and virulence inhibitory potentials of MA. Hence, MA could be clinically utilized to control infections caused by C. albicans. BIOLOGICAL SIGNIFICANCE: The conventional antifungal drugs acquire single target pattern by regulating either sterol synthesis or drug efflux pump in C. albicans that ushers drug-resistance. But Myristic acid attenuates C. albicans virulence by negative regulation of proteins involved in sterol synthesis &amp; uptake, sphingolipids and antioxidant activity. In the current study, the multi-target efficacy and the ability to inhibit biofilm and hyphae mediated virulence factors without affecting the cellular metabolism of C. albicans marks myristic acid as a potent anti-candida agent against drug resistant Candida species.},
}
@article {pmid31452954,
year = {2019},
author = {Barkarmo, S and Longhorn, D and Leer, K and Johansson, CB and Stenport, V and Franco-Tabares, S and Kuehne, SA and Sammons, R},
title = {Biofilm formation on polyetheretherketone and titanium surfaces.},
journal = {Clinical and experimental dental research},
volume = {5},
number = {4},
pages = {427-437},
doi = {10.1002/cre2.205},
pmid = {31452954},
issn = {2057-4347},
abstract = {Objective: Polyetheretherketone (PEEK) is a polymer used in devices in orthopedic and dental rehabilitation. The aim of this in vitro study was to compare biofilm formation by a range of important oral bacterial species on PEEK, blasted PEEK, commercially pure titanium (cp-Ti), and titanium-6 aluminium-4 vanadium (Ti6Al4V).<br><br>Material and methods: Coin-shaped samples were manufactured, and the surfaces were characterized using optical interferometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and contact angle measurements. Bacterial species of Streptococcus sanguinis, Streptococcus oralis, Enterococcus faecalis, and Streptococcus gordonii were cultured on the four material surfaces for varying amounts of time. Biofilms were quantified following staining with crystal violet.<br><br>Results: Roughness and contact angle results showed blasted PEEK > PEEK > cp-Ti = Ti6Al4V. There was increased biofilm formation on blasted PEEK by S. sanguinis, S. oralis, and S. gordonii, whereas the bacterial adhesion was similar on PEEK, cp-Ti, and Ti6Al4V. The bacterial growth of E. faecalis was significantly higher on cp-Ti compared with the other three groups.<br><br>Conclusion: The results, taking into consideration the biofilm formation, suggest that PEEK should perform as well as cp-Ti or TiAl6V4 when used as a dental restorative material.},
}
@article {pmid31452924,
year = {2019},
author = {McCall, AD and Pathirana, RU and Prabhakar, A and Cullen, PJ and Edgerton, M},
title = {Candida albicans biofilm development is governed by cooperative attachment and adhesion maintenance proteins.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {21},
doi = {10.1038/s41522-019-0094-5},
pmid = {31452924},
issn = {2055-5008},
support = {F31 DE024346/DE/NIDCR NIH HHS/United States ; R01 DE010641/DE/NIDCR NIH HHS/United States ; R01 DE022720/DE/NIDCR NIH HHS/United States ; },
abstract = {The opportunistic fungal pathogen Candida albicans is capable of adhering to the oral mucosa despite forces created by salivary flow. Although many fungal adhesion proteins have been identified, less is known about the temporal development of cell adhesion and biofilm growth in a flow environment. In this study, we use a flow system with real-time imaging of C. albicans cells as they adhere and grow. Rates of cell attachment and dispersion of C. albicans knockout strains of putative adhesins, transcription factors, and deletions with a hyperfilamentous phenotype were quantified during 18 h of biofilm development. Cell adhesion under flow is a multi-phase process initiated with cell rolling, then an initial firm attachment to the substrate occurs. After attachment, cells enter a growth phase where cells either commit to adherence or disperse. C. albicans Δeap1, Δhwp2, Δhyr1, and Δihd1 cells had significantly reduced initial attachment and subsequent adhesion, while Δals1/Δals3 had no change in initial attachment but reduced adhesion maintenance. WT cells had increased adhesion during the late growth phase when hyphae were more highly expressed. Hyperfilamentous strains had 10-fold higher total biofilm growth, a result of significantly reduced detachment rates, showing that hyphal morphogenesis is important for adhesion maintenance in the developing biofilm. The rate of C. albicans biomass dispersion was most important for determining the density of the mature biomass. Adhesion maintenance was mediated in part by Ywp1, a protein previously thought to regulate dispersion, thus it functions as an adhesion maintenance protein in C. albicans.},
}
@article {pmid31451500,
year = {2019},
author = {Rodríguez-Sevilla, G and Crabbé, A and García-Coca, M and Aguilera-Correa, JJ and Esteban, J and Pérez-Jorge, C},
title = {Antimicrobial treatment provides a competitive advantage to Mycobacterium abscessus in a dual species biofilm with Pseudomonas aeruginosa.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01547-19},
pmid = {31451500},
issn = {1098-6596},
abstract = {The physiological factors that contribute to Mycobacterium abscessus lung infections remain unclear. We determined if antibiotic treatment targeting a major CF pathogen (i.e. Pseudomonas aeruginosa) could provide the ideal conditions for the establishment of M. abscessus infection. Our data showed that P. aeruginosa inhibits M. abscessus biofilm formation under control conditions, and that antimicrobial therapy selectively targeting P. aeruginosa diminishes this competitive interaction, hereby increasing M. abscessus survival.},
}
@article {pmid31451499,
year = {2019},
author = {Albano, M and Karau, MJ and Greenwood-Quaintance, KE and Osmon, DR and Oravec, CP and Berry, DJ and Abdel, MP and Patel, R},
title = {In vitro Activity of Rifampin, Rifabutin, Rifapentine and Rifaximin Against Planktonic and Biofilm States of Staphylococci Isolated from Periprosthetic Joint Infection.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.00959-19},
pmid = {31451499},
issn = {1098-6596},
abstract = {in vitro activities of rifampin, rifabutin, rifapentine and rifaximin were tested against 200 PJI-associated staphylococci. Seven rifampin-resistant isolates had MICs ≥4 μg/mL. Three isolates had rifampin MICs 0.25-1μg/mL and harbored a Asp471Gly RpoB variant. The remaining isolates had rifampin MICs ≤0.016 μg/mL. Rifampin, rifabutin, rifapentine and rifaximin MBBC50 values for rifampin-susceptible isolates were 8, 1, 2, 4 (S. aureus), and 2, 0.06, 0.25, 0.5 (S. epidermidis) μg/mL, respectively. Non-rifampin rifamycins have promising staphylococcal anti-biofilm activity.},
}
@article {pmid31450779,
year = {2019},
author = {Llamazares, C and Sanz Del Olmo, N and Ortega, P and Gómez, R and Soliveri, J and de la Mata, FJ and García-Gallego, S and Copa-Patiño, JL},
title = {Antibacterial Effect of Carbosilane Metallodendrimers in Planktonic Cells of Gram-Positive and Gram-Negative Bacteria and Staphylococcus aureus Biofilm.},
journal = {Biomolecules},
volume = {9},
number = {9},
pages = {},
doi = {10.3390/biom9090405},
pmid = {31450779},
issn = {2218-273X},
support = {CTQ2017-86224-P//Ministerio de Economía y Competitividad/ ; Consortium IMMUNOTHERCAN B2017/BMD-3733//Comunidad de Madrid/ ; Consortium NANODENDMED-II B2017/BMD-3703//Comunidad de Madrid/ ; Research Talent Attraction Program 2017-T2/IND-5243//Comunidad de Madrid/ ; Project SBPLY/17/180501/000358//Junta de Comunidades de Castilla-La Mancha/ ; CIBER-BBN//Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina/ ; },
abstract = {Antibiotic resistance is currently one of the main threats to public health security. Biofilm formation is a resistance mechanism that is responsible for most human bacterial infections and requires new and effective therapeutic approaches, such as those provided by nanotechnology. In this work, the antibacterial effect of carbosilane metallodendrimers with different metals (copper(II) and ruthenium(II)), ligands (chloride and nitrate) and generations (generation 0, 1 and 2) has been studied using planktonic Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Furthermore, the ability of the metallodendrimers to avoid the formation of S. aureus biofilms was also evaluated. The results showed a promising biocide activity in both types of planktonic bacteria, especially for first-generation dendrimers, which arises from the metal complexation to the dendrimer. Cu(II) metallodendrimers require lower concentration than Ru(II) counterpart to inhibit the production of S. aureus biofilms, but none produce hemolysis at the inhibitory concentrations and can be safely used as antibacterial agents. In particular, the first-generation Cu(II) metallodendrimer with nitrate ligands displayed the most promising properties to continue with further studies in both planktonic cells and biofilms.},
}
@article {pmid31450696,
year = {2019},
author = {Smolobochkin, A and Gazizov, A and Sazykina, M and Akylbekov, N and Chugunova, E and Sazykin, I and Gildebrant, A and Voronina, J and Burilov, A and Karchava, S and Klimova, M and Voloshina, A and Sapunova, A and Klimanova, E and Sashenkova, T and Allayarova, U and Balakina, A and Mishchenko, D},
title = {Synthesis of Novel 2-(Het)arylpyrrolidine Derivatives and Evaluation of Their Anticancer and Anti-Biofilm Activity.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {17},
pages = {},
doi = {10.3390/molecules24173086},
pmid = {31450696},
issn = {1420-3049},
abstract = {A library of novel 2-(het)arylpyrrolidine-1-carboxamides were obtained via a modular approach based on the intramolecular cyclization/Mannich-type reaction of N-(4,4-diethoxybutyl)ureas. Their anti-cancer activities both in vitro and in vivo were tested. The in vitro activity of some compounds towards M-Hela tumor cell lines was twice that of the reference drug tamoxifen, whereas cytotoxicity towards normal Chang liver cell did not exceed the tamoxifen toxicity. In vivo studies showed that the number of surviving animals on day 60 of observation was up to 83% and increased life span (ILS) was up to 447%. Additionally, some pyrrolidine-1-carboxamides possessing a benzofuroxan moiety obtained were found to effectively suppress bacterial biofilm growth. Thus, these compounds are promising candidates for further development both as anti-cancer and anti-bacterial agents.},
}
@article {pmid31450579,
year = {2019},
author = {Wijesundara, NM and Rupasinghe, HPV},
title = {Herbal Tea for the Management of Pharyngitis: Inhibition of Streptococcus pyogenes Growth and Biofilm Formation by Herbal Infusions.},
journal = {Biomedicines},
volume = {7},
number = {3},
pages = {},
doi = {10.3390/biomedicines7030063},
pmid = {31450579},
issn = {2227-9059},
support = {CRDPJ 448052//Natural Sciences and Engineering Research Council of Canada/ ; },
abstract = {Herbal teas are becoming popular as functional beverages due to their various health promotional properties. This study aimed at assessing 13 hot water infusions (HWIs) from different herbs against streptococcal pharyngitis (strep throat). Licorice root exhibited the lowest minimum inhibitory concentrations (MIC) of 1.56 mg/mL, followed by barberry root, thyme, and oregano flowering shoots, with a MIC of 3.13 mg/mL. At their respective minimum bactericidal concentrations (MBC), licorice showed the bactericidal effect on S. pyogenes within 12 h after exposure while others need 24 h for a similar outcome. The HWIs exhibited inhibitory activity on biofilm formation, ranging from 1.56 to 6.25 mg/mL, which confirmed by ruptured cells or clusters of dead cell debris observed in scanning electron microscope (SEM). Overall, non-toxic concentrations of efficacious HWIs from licorice root, barberry root, thyme, and oregano flowering shoots may provide potential sources for developing herbal teas or biomedicine for the management of S. pyogenes infections.},
}
@article {pmid31450202,
year = {2019},
author = {Sinharoy, A and Baskaran, D and Pakshirajan, K},
title = {A novel carbon monoxide fed moving bed biofilm reactor for sulfate rich wastewater treatment.},
journal = {Journal of environmental management},
volume = {249},
number = {},
pages = {109402},
doi = {10.1016/j.jenvman.2019.109402},
pmid = {31450202},
issn = {1095-8630},
abstract = {In this study, a moving bed biofilm reactor was used for biodesulfuruization using CO as the sole carbon substrate. The effect of hydraulic retention time (HRT), sulfate loading rate and CO loading rate on sulfate and CO removal was examined. At 72, 48 and 24 h HRT, the sulfate removal was 93.5%, 91.9% and 80.1%, respectively. An increase in the sulfate loading reduced the sulfate reduction efficiency, which, however, was improved by increasing the CO flow rate into the MBBR. Best results in terms of sulfate reduction (>80%) were obtained for low inlet sulfate and high CO loading conditions. The CO utilization was very high at 85% throughout the study, except during the last phase of the continuous bioreactor operation it was around 70%. An artificial neural network based model was successfully developed and optimized to accurately predict the bioreactor performance in terms of both sulfate reduction and CO utilization. Overall, this study showed an excellent potential of the moving bed biofilm bioreactor for efficient sulfate reduction even under high loading conditions.},
}
@article {pmid31448272,
year = {2019},
author = {Saggu, SK and Jha, G and Mishra, PC},
title = {Enzymatic Degradation of Biofilm by Metalloprotease From Microbacterium sp. SKS10.},
journal = {Frontiers in bioengineering and biotechnology},
volume = {7},
number = {},
pages = {192},
doi = {10.3389/fbioe.2019.00192},
pmid = {31448272},
issn = {2296-4185},
abstract = {Enzymes have replaced or decreased usage of toxic chemicals for industrial and medical applications leading toward sustainable chemistry. In this study, we report purification and characterization of a biofilm degrading protease secreted by Microbacterium sp. SKS10. The protease was identified as a metalloprotease, Peptidase M16 using mass spectrometry. It showed optimum activity at 60°C, pH 12 and retained its activity in the presence of various salts and organic solvents. The enzyme was able to degrade biofilms efficiently at enzyme concentration lower than other known enzymes such as papain, trypsin and α-amylase. The presence of this protease increased the accessibility of antibiotics inside the biofilm, and was found to be non-cytotoxic toward human epidermoid carcinoma cells (A431) at the effective concentration for biofilm degradation. Thus, this protease may serve as an effective tool for management of biofilms.},
}
@article {pmid31448253,
year = {2019},
author = {Ciccozzi, M and Cella, E and Lai, A and De Florio, L and Antonelli, F and Fogolari, M and Di Matteo, FM and Pizzicannella, M and Colombo, B and Dicuonzo, G and Angeletti, S},
title = {Phylogenetic Analysis of Multi-Drug Resistant Klebsiella pneumoniae Strains From Duodenoscope Biofilm: Microbiological Surveillance and Reprocessing Improvements for Infection Prevention.},
journal = {Frontiers in public health},
volume = {7},
number = {},
pages = {219},
doi = {10.3389/fpubh.2019.00219},
pmid = {31448253},
issn = {2296-2565},
abstract = {Duodenoscopes have been described as potential vehicles of patient-to-patient transmission of multi-drug resistant organisms. Carbapenem-resistant Enterobacteriaceae duodenoscope related infections have been described by the Center for Disease Control and the US Food and Drug Administration consequently to outbreaks occurring in the United States. These evidences suggested that improved microbiological surveillance and endoscope design optimization could represent valid tools to improve infection control. At this aim, in this study an example of duodenoscope microbiological surveillance and reprocessing improvement analyzing strains component of bacterial biofilm by phylogenetic analysis has been proposed. From September 2016 to December 2017, duodenoscope instruments were subjected to microbial surveillance by post-reprocessing cultures of liquid collected by internal channels of instruments after injection and aspiration cycles and membrane filtration. During surveillance seventeen Klebsiella pneumoniae, of which 10/17 (58.8%) MDR and KPC strains were collected from duodenoscope instruments plus one MDR Klebsiella pneumoniae strain from the rectal swab performed before ERCP procedure in an inpatient. The surveillance allowed evidencing potential failure of reprocessing procedure and performing consequent reprocessing improvements including the contaminated instruments quarantine until their negativity. Phylogenetic analysis of whole genome sequence of duodenoscope strains plus inpatients MDR strains, showed intermixing between duodenoscopes and inpatients, as evidenced by minimum spanning tree and time-scale Maximum Clade Credibility tree. In minimum spanning tree, three groups have been evidenced. Group I including Klebsiella pneumoniae strains, isolated from inpatients before microbiological surveillance adoption; group II including intermixed Klebsiella pneumoniae strains isolated from inpatients and Klebsiella pneumoniae strains isolated from duedonoscopes and group III including Klebsiella pneumoniae strains exclusively from duedonoscope instruments. In the Maximum Credibility Tree, a statistically supported cluster including two Klebsiella pneumoniae strains from duedonoscope instruments and one strains isolated from an inpatient was showed. From the first microbiologic surveillance performed on September 2016 and after the reprocessing improvement adoption, none MDR or susceptible Klebsiella pneumoniae strain was isolated in the following surveillance periods. In conclusion, these results should encourage hospital board to perform microbiological surveillance of duodenoscopes as well as of patients, by rectal swabs culture, and rapid molecular testing for antimicrobial resistance before any endoscopic invasive procedure.},
}
@article {pmid31447791,
year = {2019},
author = {Kesy, K and Oberbeckmann, S and Kreikemeyer, B and Labrenz, M},
title = {Spatial Environmental Heterogeneity Determines Young Biofilm Assemblages on Microplastics in Baltic Sea Mesocosms.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1665},
doi = {10.3389/fmicb.2019.01665},
pmid = {31447791},
issn = {1664-302X},
abstract = {Microplastics in aquatic environments provide novel habitats for surface-colonizing microorganisms. Given the continuing debate on whether substrate-specific properties or environmental factors prevail in shaping biofilm assemblages on microplastics, we examined the influence of substrate vs. spatial factors in the development of bacterial assemblages on polyethylene (PE), polystyrene (PS), wood, and seston and in the free-living fraction. Further, the selective colonization of microplastics by potential pathogens was investigated because among the bacterial species found in microplastic-associated biofilms are potentially pathogenic Vibrio spp. Due to their persistence and great dispersal potential, microplastics could act as vectors for these potential pathogens and for biofilm assemblages in general. Incubation experiments with these substrates were conducted for 7 days during a summer cruise along the eastern Baltic Sea coastline in waters covering a salinity gradient of 4.5-9 PSU. Bacterial assemblages were analyzed using 16S rRNA-gene amplicon sequencing, distance-based redundancy analyses, and the linear discriminant analysis effect size method to identify taxa that were significantly more abundant on the plastics. The results showed that the sample type was the most important factor structuring bacterial assemblages overall. Surface properties were less significant in differentiating attached biofilms on PE, PS, and wood; instead, environmental factors, mainly salinity, prevailed. A potential role for inorganic-nutrient limitations in surface-specific attachment was identified as well. Alphaproteobacteria (Sphingomonadaceae, Devosiaceae, and Rhodobacteraceae) and Gammaproteobacteria (Alteromonadaceae and Pseudomonas) were distinctive for the PE- and PS-associated biofilms. Vibrio was more abundant on the PE and PS biofilms than on seston, but its abundances were highest on wood and positively correlated with salinity. These results corroborate earlier findings that microplastics constitute a habitat for biofilm-forming microorganisms distinct from seston, but less from wood. In contrast to earlier reports of low Vibrio numbers on microplastics, these results also suggest that vibrios are early colonizers of surfaces in general. Spatial as well as temporal dynamics should therefore be considered when assessing the potential of microplastics to serve as vectors for bacterial assemblages and putative pathogens, as these parameters are major drivers of biofilm diversity.},
}
@article {pmid31447460,
year = {2019},
author = {Wu, S and Liu, Y and Zhang, H and Lei, L},
title = {A new transformation method with nanographene oxides of antisense carrying yycG RNA improved antibacterial properties on methicillin-resistant Staphylococcus aureus biofilm.},
journal = {The Journal of veterinary medical science},
volume = {},
number = {},
pages = {},
doi = {10.1292/jvms.19-0216},
pmid = {31447460},
issn = {1347-7439},
abstract = {Staphylococcus aureus have the potential to opportunistically cause infectious diseases. The aim of this study was to determine the antimicrobial effects of novel graphene oxide (GO)-polyethylenimine (PEI)-based antisense yycG (ASyycG) on the inhibition of methicillin-resistant S. aureus (MRSA) biofilm formation. In current study, a novel GO-PEI-based recombinant ASyycG vector transformation strategy was developed to produce ASyycG. The mechanical features including zeta-potential and particle size distributions were evaluated by: (1) GO; (2) GO-PEI; and (3) GO-PEI-ASyycG. The recombinant ASyycG vector was transformed into MRSA cells, and the expression levels of the yycF/G and icaADB genes were determined and compared by quantitative real-time PCR (qPCR) assays. The recombinant ASyycG plasmids were subsequently modified with a gene encoding enhanced green fluorescent protein (ASyycG-eGFP) as a reporter gene, and the transformation efficiency was assessed by the fluorescence intensity. The biofilm biomass and bacterial viability of the MRSA strains were evaluated by crystal violet assay, colony-forming unit assays and confocal laser scanning microscopy. The results showed that the Z-average sizes of GO-PEI-ASyycG were much larger than those of GO or GO-PEI. The GO-PEI-based strategy significantly increased the efficiency of ASyycG transformation. The GO-PEI-ASyycG-transformed MRSA strain had the lowest expression levels of the biofilm formation-associated genes. Furthermore, GO-PEI-ASyycG suppressed biofilm aggregation and improved bactericidal effects on the MRSA after 24 hr of biofilm establishment. Our findings demonstrated that GO-PEI based antisense yycG RNA will be an effective method for management of MRSA infections.},
}
@article {pmid31445309,
year = {2019},
author = {Wu, X and Pan, J and Li, M and Li, Y and Bartlam, M and Wang, Y},
title = {Selective enrichment of bacterial pathogens by microplastic biofilm.},
journal = {Water research},
volume = {165},
number = {},
pages = {114979},
doi = {10.1016/j.watres.2019.114979},
pmid = {31445309},
issn = {1879-2448},
abstract = {Microplastics have been found to be ubiquitous in freshwater ecosystems, providing a novel substrate for biofilm formation. Here, we incubated biofilm on microplastics and two natural substrates (rock and leaf) under a controlled environment to investigate the differences of microbial community structure, antibiotic resistance gene (ARG) profiles, and ARG microbial hosts between biofilms on three types of substrates. Results from high-throughput sequencing of 16S rRNA gene revealed that microplastic biofilm had a distinctive community structure. Network analyses suggested that microplastic biofilm possessed the highest node connected community, but with lower average path length, network diameter and modularity compared with biofilm on two natural particles. Metagenomic analyses further revealed microplastic biofilm with broad-spectrum and distinctive resistome. Specifically, according to taxonomic annotation of ARG microbial hosts, two opportunisitic human pathogens (Pseudomonas monteilii, Pseudomonas mendocina) and one plant pathogen (Pseudomonas syringae) were detected only in the microplastic biofilm, but not in biofilms formed on natural substrates. Our findings suggest that microplastic is a novel microbial niche and may serve as a vector for ARGs and pathogens to new environment in river water, generating freshwater environmental risk and exerting adverse impacts on human health.},
}
@article {pmid31444121,
year = {2019},
author = {Cui, MH and Sangeetha, T and Gao, L and Wang, AJ},
title = {Efficient azo dye wastewater treatment in a hybrid anaerobic reactor with a built-in integrated bioelectrochemical system and an aerobic biofilm reactor: Evaluation of the combined forms and reflux ratio.},
journal = {Bioresource technology},
volume = {},
number = {},
pages = {122001},
doi = {10.1016/j.biortech.2019.122001},
pmid = {31444121},
issn = {1873-2976},
abstract = {A combined process that consisted of a hybrid anaerobic reactor (HAR) with an integral bioelectrochemical system and aerobic biofilm reactor (ABFR) was established for simulated azo dye wastewater treatment (domestic wastewater containing dye acid orange 7). The split combination form that separated HAR and ABFR into two individual reactors recorded a decolorization efficiency of 81.23 ± 0.12%, which was about 8% higher than that HAR and ABFR were stacked together into a single up-flow reactor. Implementation of reflux improved the decolorization and chemical oxygen demand (COD) removal in both the processes. Decolorization efficiency achieved 97.52 ± 0.66% in split process at a reflux ratio of 1 and the COD was 89 ± 2 mg/L in the final effluent. Further increasing the reflux ratio to 3 did not have any significance in treatment performance of the reactors. This study comprehensively revealed the influence of combination forms and reflux ratio on the performance of combined process.},
}
@article {pmid31444120,
year = {2019},
author = {Sun, S and Liu, J and Zhang, M and He, S},
title = {Simultaneous improving nitrogen removal and decreasing greenhouse gas emission with biofilm carriers addition in ecological floating bed.},
journal = {Bioresource technology},
volume = {},
number = {},
pages = {121944},
doi = {10.1016/j.biortech.2019.121944},
pmid = {31444120},
issn = {1873-2976},
abstract = {Ecological floating bed (EFB) is a green technology for treatment of micro-polluted wastewater. However, its nitrogen removal efficiency is still unsatisfactory. In this study, two EFBs with additional carbon source were established to explore biofilm carriers addition on nitrogen removal and greenhouse gas (GHG) emissions at different C/N ratios and temperatures. Results showed that biofilm carriers addition increased nitrification and nitrogen removal efficiencies in EFB, and more denitrifying and nitrifying bacteria were attached to the biofilm carriers. Higher N2O and CH4 emissions were found in control EFB without biofilm carriers addition which was consistent with higher nitrite accumulation. In addition, high-throughput sequencing analysis revealed that adding biofilm carriers could improve the richness and diversity of biological communities. For EFB with additional carbon source treating secondary effluent, adding biofilm carrier can obtain higher TN removal efficiency and lower greenhouse gas emission.},
}
@article {pmid31443467,
year = {2019},
author = {Arul Selvaraj, RC and Rajendran, M and Nagaiah, HP},
title = {Re-Potentiation of β-Lactam Antibiotic by Synergistic Combination with Biogenic Copper Oxide Nanocubes against Biofilm Forming Multidrug-Resistant Bacteria.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {17},
pages = {},
doi = {10.3390/molecules24173055},
pmid = {31443467},
issn = {1420-3049},
support = {(Ref: NM/NS/01/2015 (G) dated 30 May,2016//DST, Nano Mission, India/ ; },
abstract = {Biofilm-associated tissue and device infection is a major threat to therapy. The present work aims to potentiate β-lactam antibiotics with biologically synthesized copper oxide nanoparticles. The synergistic combination of amoxyclav with copper oxide nanoparticles was investigated by checkerboard assay and time-kill assay against bacteria isolated from a burn wound and a urinary catheter. The control of biofilm formation and extracellular polymeric substance production by the synergistic combination was quantified in well plate assay. The effect of copper oxide nanoparticles on the viability of human dermal fibroblasts was evaluated. The minimum inhibitory concentration and minimum bactericidal concentration of amoxyclav were 70 μg/mL and 140 μg/mL, respectively, against Proteus mirabilis and 50 μg/mL and 100 μg/mL, respectively, against Staphylococcus aureus. The synergistic combination of amoxyclav with copper oxide nanoparticles reduced the minimum inhibitory concentration of amoxyclav by 16-fold against P. mirabilis and 32-fold against S. aureus. Above 17.5 μg/mL, amoxyclav exhibited additive activity with copper oxide nanoparticles against P. mirabilis. The time-kill assay showed the efficacy of the synergistic combination on the complete inhibition of P. mirabilis and S. aureus within 20 h and 24 h, respectively, whereas amoxyclav and copper oxide nanoparticles did not inhibit P. mirabilis and S. aureus until 48 h. The synergistic combination of amoxyclav with copper oxide nanoparticles significantly reduced the biofilm formed by P. mirabilis and S. aureus by 85% and 93%, respectively. The concentration of proteins, carbohydrates, and DNA in extracellular polymeric substances of the biofilm was significantly reduced by the synergistic combination of amoxyclav and copper oxide nanoparticles. The fibroblast cells cultured in the presence of copper oxide nanoparticles showed normal morphology with 99.47% viability. No cytopathic effect was observed. Thus, the study demonstrated the re-potentiation of amoxyclav by copper oxide nanoparticles.},
}
@article {pmid31443115,
year = {2019},
author = {Wroe, JA and Johnson, CT and García, AJ},
title = {Bacteriophage delivering hydrogels reduce biofilm formation in vitro and infection in vivo.},
journal = {Journal of biomedical materials research. Part A},
volume = {},
number = {},
pages = {},
doi = {10.1002/jbm.a.36790},
pmid = {31443115},
issn = {1552-4965},
support = {F30AR069472//National Institutes of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health/ ; R01AR062920//National Institutes of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health/ ; //The Georgia Tech President's Undergraduate Research Award (PURA)/ ; },
abstract = {Implanted orthopedic devices become infected more frequently than any other implanted surgical device. These infections can be extremely costly and result in significant patient morbidity. Current treatment options typically involve the long term, systemic administration of a combination of antibiotics, often followed by implant removal. Here we engineered an injectable hydrogel capable of encapsulating Pseudomonas aeruginosa bacteriophage and delivering active phage to the site of bone infections. Bacteriophage retain their bacteriolytic activity after encapsulation and release from the hydrogel, and their rate of release from the hydrogel can be controlled by gel formulation. Bacteriophage-encapsulating hydrogels effectively kill their host bacteria in both planktonic and biofilm phenotypes in vitro without influencing the metabolic activity of human mesenchymal stromal cells. Bacteriophage-encapsulating hydrogels were used to treat murine radial segmental defects infected with P. aeruginosa. The hydrogels achieved a 4.7-fold reduction in live P. aeruginosa counts at the infection site compared to bacteriophage-free hydrogels at 7 days postimplantation. These results support the development of bacteriophage-delivering hydrogels to treat local bone infections.},
}
@article {pmid31442835,
year = {2019},
author = {Wu, X and Cen, Q and Addy, M and Zheng, H and Luo, S and Liu, Y and Cheng, Y and Zhou, W and Chen, P and Ruan, R},
title = {A novel algal biofilm photobioreactor for efficient hog manure wastewater utilization and treatment.},
journal = {Bioresource technology},
volume = {292},
number = {},
pages = {121925},
doi = {10.1016/j.biortech.2019.121925},
pmid = {31442835},
issn = {1873-2976},
abstract = {This study developed a high-efficiency algal biofilm photobioreactor for microalgae by designing a special array of curtain membrane components. This paper also discusses the growth and nutrient composition of Chlorella vulgaris, and hog manure wastewater utilization and purification. It was found that after about 5 days of culture, the biomass of C. vulgaris on the membrane could reach as high as 7.37 g/m2 and the algae were easily harvested by mechanical scraping. The lipid content of C. vulgaris on the membrane structure was 10.17% while the lipid content of the algae in suspension was 14.29%. The light intensity showed a significant effect on the fatty acid composition. The C. vulgaris grew very well, and achieved deep purification of the hog manure wastewater; the COD, TP, TN, and NH4+-N removal rates reached 95.67%, 64.40%, 69.55%, and 91.24%, respectively.},
}
@article {pmid31440218,
year = {2019},
author = {Todhanakasem, T and Salangsing, OL and Koomphongse, P and Kaewket, S and Kanokratana, P and Champreda, V},
title = {Zymomonas mobilis Biofilm Reactor for Ethanol Production Using Rice Straw Hydrolysate Under Continuous and Repeated Batch Processes.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1777},
doi = {10.3389/fmicb.2019.01777},
pmid = {31440218},
issn = {1664-302X},
abstract = {Plastic composited corn silk was developed as a biotic/abiotic carrier for Zymomonas mobilis biofilm formation for the purpose of ethanol production. Furthermore, we explored the use of rice straw hydrolysate as substrate in both multistage continuous culture and repeated batch processes and compared the ethanol production efficiency by two strains of Z. mobilis. Biofilm formed by bacterial strains Z. mobilis ZM4 and TISTR551 were detected, and its proficiencies were compared under various conditions by scanning electron microscopy (SEM) and crystal violet assays. The greatest biofilm formed by both strains was found on day five after the inoculation. Z. mobilis strain ZM4 grown in repeated batch biofilm reactors produced higher yields of ethanol than TISTR551 grown under the same conditions, while TISTR551 produced higher yields of ethanol in the multistage continuous process. The yields were highly maintained, with no significant differences (p < 0.05) among the three consecutive repeated batches. These experiments highlight exciting uses for agricultural byproducts in the production of ethanol using Z. mobilis biofilm reactors.},
}
@article {pmid31440064,
year = {2019},
author = {Shariati, A and Asadian, E and Fallah, F and Azimi, T and Hashemi, A and Yasbolaghi Sharahi, J and Taati Moghadam, M},
title = {Evaluation of Nano-curcumin effects on expression levels of virulence genes and biofilm production of multidrug-resistant Pseudomonas aeruginosa isolated from burn wound infection in Tehran, Iran.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {2223-2235},
doi = {10.2147/IDR.S213200},
pmid = {31440064},
issn = {1178-6973},
abstract = {Background: P. aeruginosa is considered as one of the most important pathogens, and high antibiotic resistance to P. aeruginosa has become an alarming concern. This study attempts to further improve curcumin solubility and stability by producing the involved nanoparticle and investigate the effect of this nanoparticle on those virulence genes of P. aeruginosa in pathogenicity and biofilm formation.<br><br>Methods: In this study, the curcumin nanoparticles were synthesized and characterized, and the antibacterial and antibiofilm effects of Nano-curcumin and curcumin were investigated by microdilution broth and microtiter plate, respectively. In addition, cytotoxic effect of Nano-curcumin on human epithelial cell lines (A549) was determined. The effects of Nano-curcumin on P. aeruginosa virulence genes, mexD, mexB, and mexT (efflux pumps), lecA (adhesion), nfxB (negative regulator of MexCD-OprJ), and rsmZ (biofilm formation) were determined using real-time quantitative PCR.<br><br>Results: Synthesized Nano-curcumins were soluble in water, which inhibited the growth of multidrug-resistant (MDR) P. aeruginosa at 128 µg/mL, whereas it was inhibited at 256 µg/mL for soluble curcumin in DMSO. Sub-inhibitory concentrations of Nano-curcumin reduced biofilm formation and, at 64 μg/mL, disrupted 58% of the established bacterial biofilms. In addition, curcumin nanoparticle downregulated the transcription of virulence genes except nfxB and exerted no cytotoxic effect on human epithelial cell lines (A549).<br><br>Conclusions: Results suggest that Nano-curcumin could be potentially used to reduce P. aeruginosa virulence and biofilm. However, in vivo studies with respect to an animal model are necessary to validate these results.},
}
@article {pmid31439876,
year = {2019},
author = {Champion, AE and Catanzaro, KCF and Bandara, AB and Inzana, TJ},
title = {Formation of the Francisella tularensis Biofilm is Affected by Cell Surface Glycosylation, Growth Medium, and a Glucan Exopolysaccharide.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {12252},
doi = {10.1038/s41598-019-48697-x},
pmid = {31439876},
issn = {2045-2322},
support = {DE-FG02-93ER20097//U.S. Department of Energy (DOE)/ ; },
abstract = {Biofilms are matrix-associated communities that enable bacteria to colonise environments unsuitable for free-living bacteria. The facultative intracellular pathogen Francisella tularensis can persist in water, amoebae, and arthropods, as well as within mammalian macrophages. F. tularensis Types A and B form poor biofilms, but F. tularensis mutants lacking lipopolysaccharide O-antigen, O-antigen capsule, and capsule-like complex formed up to 15-fold more biofilm than fully glycosylated cells. The Type B live vaccine strain was also 50% less capable of initiating surface attachment than mutants deficient in O-antigen and capsule-like complex. However, the growth medium of all strains tested also influenced the formation of biofilm, which contained a novel exopolysaccharide consisting of an amylose-like glucan. In addition, the surface polysaccharide composition of the bacterium affected the protein:DNA:polysaccharide composition of the biofilm matrix. In contrast, F. novicida attached to surfaces more efficiently and made a more robust biofilm than Type A or B strains, but loss of O-antigen or capsule-like complex did not significantly affect F. novicida biofilm formation. These results indicated that suppression of surface polysaccharides may promote biofilm formation by F. tularensis Types A and B. Whether biofilm formation enhances survival of F. tularensis in aquatic or other environmental niches has yet to be determined.},
}
@article {pmid31439670,
year = {2019},
author = {Kaus, K and Biester, A and Chupp, E and Lu, J and Visudharomn, C and Olson, R},
title = {The 1.9 Å crystal structure of the extracellular matrix protein Bap1 from Vibrio cholerae provides insights into bacterial biofilm adhesion.},
journal = {The Journal of biological chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1074/jbc.RA119.008335},
pmid = {31439670},
issn = {1083-351X},
abstract = {Growth of the cholera bacterium Vibrio cholerae in a biofilm community contributes to both its pathogenicity and survival in aquatic environmental niches. The major components of V. cholerae biofilms include Vibriopolysaccharide (VPS) and the extracellular matrix proteins RbmA, RbmC, and Bap1. To further elucidate the previously observed overlapping roles of Bap1 and RbmC in biofilm architecture and surface attachment, here we investigated the structural and functional properties of Bap1. Soluble expression of Bap1 was possible only after the removal of an internal 57-amino-acid-long hydrophobic insertion sequence. The crystal structure of Bap1 at 1.9 Å resolution revealed a two-domain assembly made up of an eight-bladed β-propeller interrupted by a β-prism domain. The structure also revealed metal-binding sites within canonical calcium blade motifs, which appear to have structural rather than functional roles. Contrary to results previously observed with RbmC, the Bap1 β-prism domain did not exhibit affinity for complex N-glycans, suggesting an altered role of this domain in biofilm-surface adhesion. Native polyacrylamide gel shift analysis did suggest that Bap1 exhibits lectin activity with a preference for anionic and/or linear polysaccharides. Our results suggest a model for V. cholerae biofilms in which Bap1 and RbmC play dominant but differing adhesive roles in biofilms, allowing bacterial attachment to diverse environmental or host surfaces.},
}
@article {pmid31438836,
year = {2019},
author = {Pires, MEE and Parreira, AG and Silva, TNL and Colares, HC and da Silva, JA and de Magalhães, JT and Galdino, AS and Gonçalves, DB and Granjeiro, JM and Granjeiro, PA},
title = {Recent patents on impact of lipopeptide on the biofilm formation onto titanium and stainless steel surfaces.},
journal = {Recent patents on biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.2174/1872208313666190822150323},
pmid = {31438836},
issn = {2212-4012},
abstract = {BACKGROUND: Numerous causes of infection in arthroplasties are related to biofilm formation on implant surfaces. In order to circumvent this problem, new alternatives to prevent bacterial adhesion biosurfactants-based are emerging due to low toxicity, biodegradability and antimicrobial activity of several biosurfactants. We revised all patents relating to biosurfactants of applicability in orthopedic implants.<br><br>METHODS: This work aims to evaluate the capability of a lipopeptide produced by Bacillus subtilis ATCC 19659 isolates acting as inhibitors of the adhesion of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213 onto titanium and stainless steel surfaces and its antimicrobial activity.<br><br>RESULTS: The adhesion of the strains to the stainless-steel surface was higher than that of titanium. Preconditioning of titanium and stainless-steel surfaces with 10 mg mL-1 lipopeptide reduced the adhesion of E. coli by up to 93% and the adhesion of S. aureus by up to 99.9%, suggesting the strong potential of lipopeptides in the control of orthopedic infections. The minimal inhibitory concentration and minimum bactericidal concentration were 10 and 240 μg mL-1 for E. coli and S. aureus, respectively.<br><br>CONCLUSION: The lipopeptide produced by Bacillus subtilis ATCC 19659 presented high biotechnological application in human health against orthopedic implants infections.},
}
@article {pmid31438656,
year = {2019},
author = {Skowron, K and Wałecka-Zacharska, E and Grudlewska, K and Gajewski, P and Wiktorczyk, N and Wietlicka-Piszcz, M and Dudek, A and Skowron, KJ and Gospodarek-Komkowska, E},
title = {Disinfectant Susceptibility of Biofilm Formed by Listeria monocytogenes under Selected Environmental Conditions.},
journal = {Microorganisms},
volume = {7},
number = {9},
pages = {},
doi = {10.3390/microorganisms7090280},
pmid = {31438656},
issn = {2076-2607},
abstract = {Listeria monocytogenes is a one of the most important food-borne pathogens. Its ability to form biofilm contributes to increased resistance to disinfectants and inefficient disinfection, posing a serious threat for the food industry, and in the end the consumer. The aim of this study was the comparison of the biofilm formation ability of L. monocytogenes strains on stainless steel, under different environmental conditions (temperature, pH, NaCl concentration, nutrients availability), and the assessment of biofilm susceptibility to disinfectants. The bactericidal activity of four disinfectants in two concentrations (100% and 50% of working solution) against biofilm was conducted on four clinical strains, four strains isolated from food and one reference strain ATCC 19111. It was found that biofilm susceptibility to disinfectants was influenced by environmental conditions. Biofilm susceptibility correlated with the decrease of temperature, pH, nutrients availability and salinity of the environment. The least sensitive to disinfectants was biofilm produced at pH = 4 (the bacterial number ranged from 0.25 log CFU × cm-2 to 1.72 log CFU × cm-2) whereas the most sensitive was biofilm produced at pH = 9 (5.16 log CFU × cm-2 to 7.84 log CFU × cm-2). Quatosept was the most effective disinfectant, regardless of the conditions. In conclusion, biofilm susceptibility to disinfectants is strain-dependent and is affected by environmental conditions.},
}
@article {pmid31438629,
year = {2019},
author = {Lorenzo, D},
title = {Chloramphenicol Resurrected: A Journey from Antibiotic Resistance in Eye Infections to Biofilm and Ocular Microbiota.},
journal = {Microorganisms},
volume = {7},
number = {9},
pages = {},
doi = {10.3390/microorganisms7090278},
pmid = {31438629},
issn = {2076-2607},
abstract = {The advent of multidrug resistance among pathogenic bacteria is devastating the worth of antibiotics and changing the way of their administration, as well as the approach to use new or old drugs. The crisis of antimicrobial resistance is also due to the unavailability of newer drugs, attributable to exigent regulatory requirements and reduced financial inducements. The emerging resistance to antibiotics worldwide has led to renewed interest in old drugs that have fallen into disuse because of toxic side effects. Thus, comprehensive efforts are needed to minimize the pace of resistance by studying emergent microorganisms and optimize the use of old antimicrobial agents able to maintain their profile of susceptibility. Chloramphenicol is experiencing its renaissance because it is widely used in the treatment and prevention of superficial eye infections due to its broad spectrum of activity and other useful antimicrobial peculiarities, such as the antibiofilm properties. Concerns have been raised in the past for the risk of aplastic anemia when chloramphenicol is given intravenously. Chloramphenicol seems suitable to be used as topical eye formulation for the limited rate of resistance compared to fluoroquinolones, for its scarce induction of bacterial resistance and antibiofilm activity, and for the hypothetical low impact on ocular microbiota disturbance. Further in-vitro and in vivo studies on pharmacodynamics properties of ocular formulation of chloramphenicol, as well as its real impact against biofilm and the ocular microbiota, need to be better addressed in the near future.},
}
@article {pmid31437576,
year = {2019},
author = {Khan, F and Jeong, MC and Park, SK and Kim, SK and Kim, YM},
title = {Contribution of chitooligosaccharides to biofilm formation, antibiotics resistance and disinfectants tolerance of Listeria monocytogenes.},
journal = {Microbial pathogenesis},
volume = {136},
number = {},
pages = {103673},
doi = {10.1016/j.micpath.2019.103673},
pmid = {31437576},
issn = {1096-1208},
abstract = {Listeria monocytogenes is a food-borne pathogen present in various environmental reservoirs. It exhibits resistance and tolerance to antibiotics and sanitizing agents used in several food processing industries. It has been reported that L. monocytogenes chitinase can catalyze hydrolysis of chitin polymeric carbohydrate present in the environment and act as a virulence factor that support its survival in mammalian host cells. By taking advantage of chitinase, L. monocytogenes has both saprophytic and pathogenic lifestyles in the soil and the living host, respectively. The objective of the present study was to determine the involvement of chitin degradation products such as chitooligosaccharides (COS) in biofilm formation of L. monocytogenes. Results showed that different concentrations of COS with various molecular weight enhanced biofilm formation of L. monocytogenes. Such enhancement in biofilm formation contributed to the development of antibiotics resistance and disinfectants tolerance of cells present in the biofilm. The present article also described diverse roles of chitin, chitinase, and degradation of chitin and chitin-like substrates in saprophytic and pathogenic lifestyles of L. monocytogenes. This study offers a new direction for further exploration of the mechanisms of pathogenesis caused by L. monocytogenes.},
}
@article {pmid31437202,
year = {2019},
author = {Romero-Lastra, P and Sánchez, MC and Llama-Palacios, A and Figuero, E and Herrera, D and Sanz, M},
title = {Gene expression of Porphyromonas gingivalis ATCC 33277 when growing in an in vitro multispecies biofilm.},
journal = {PloS one},
volume = {14},
number = {8},
pages = {e0221234},
doi = {10.1371/journal.pone.0221234},
pmid = {31437202},
issn = {1932-6203},
abstract = {BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis, an oral microorganism residing in the subgingival biofilm, may exert diverse pathogenicity depending on the presence of specific virulence factors, but its gene expression has not been completely established. This investigation aims to compare the transcriptomic profile of this pathogen when growing within an in vitro multispecies biofilm or in a planktonic state.<br><br>MATERIALS AND METHODS: P. gingivalis ATCC 33277 was grown in anaerobiosis within multi-well culture plates at 37°C under two conditions: (a) planktonic samples (no hydroxyapatite discs) or (b) within a multispecies-biofilm containing Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans deposited on hydroxyapatite discs. Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM) combined with Fluorescence In Situ Hybridization (FISH) were used to verify the formation of the biofilm and the presence of P. gingivalis. Total RNA was extracted from both the multispecies biofilm and planktonic samples, then purified and, with the use of a microarray, its differential gene expression was analyzed. A linear model was used for determining the differentially expressed genes using a filtering criterion of two-fold change (up or down) and a significance p-value of <0.05. Differential expression was confirmed by Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR).<br><br>RESULTS: SEM verified the development of the multispecies biofilm and FISH confirmed the incorporation of P. gingivalis. The microarray demonstrated that, when growing within the multispecies biofilm, 19.1% of P. gingivalis genes were significantly and differentially expressed (165 genes were up-regulated and 200 down-regulated), compared with planktonic growth. These genes were mainly involved in functions related to the oxidative stress, cell envelope, transposons and metabolism. The results of the microarray were confirmed by RT-qPCR.<br><br>CONCLUSION: Significant transcriptional changes occurred in P. gingivalis when growing in a multispecies biofilm compared to planktonic state.},
}
@article {pmid31437081,
year = {2019},
author = {Sun, R and Xu, Y and Wu, Y and Tang, J and Esquivel-Elizondo, S and Kerr, PG and Staddon, PL and Liu, J},
title = {Functional sustainability of nutrient accumulation by periphytic biofilm under temperature fluctuations.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-10},
doi = {10.1080/09593330.2019.1659422},
pmid = {31437081},
issn = {1479-487X},
abstract = {Temperature can fluctuate widely between different seasons, and this may greatly impact many biological processes. However, little is known about its influence on the functioning of benthic microbial communities. Here we investigated the nutrient accumulation capability of periphytic biofilm under temperature fluctuations (17-35°C). Periphytic biofilm maintained the same nutrient accumulation capacity after experiencing the 'warming-hot-cooling' temperature fluctuation under both lab and outdoor conditions as those without temperature disturbance. In response to temperature increase, both community composition and species richness changed greatly and the increase in biodiversity was identified as being the underlying mechanism boosting the sustainable function in nutrient accumulation, indicating zero net effects of community changes. These findings provide insights into the underlying mechanisms of how benthic microbial communities adapt to temperature fluctuations to maintain nutrient accumulation capacity and elucidate that periphytic biofilm plays important roles in influencing nutrient cycling in aquatic ecosystems under temperature changes such as seasonal fluctuations.},
}
@article {pmid31435968,
year = {2019},
author = {Cho, P and Boost, MV},
title = {Evaluation of prevention and disruption of biofilm in contact lens cases.},
journal = {Ophthalmic &amp; physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists)},
volume = {},
number = {},
pages = {},
doi = {10.1111/opo.12635},
pmid = {31435968},
issn = {1475-1313},
abstract = {PURPOSE: The presence of biofilm in the lens case has been shown to be a risk factor for contamination of lenses and consequently microbial keratitis. This study aimed to evaluate effectiveness of solutions for rigid contact lenses in prevention and disruption of biofilm in lens cases and methods for biofilm detection.<br><br>METHOD: This study adopted a stepwise approach to evaluate effectiveness of four rigid lens disinfecting solutions against biofilm. These included two polyhexamethylene bigiuanide (PHMB) solutions and a chlorhexidine/PHMB-based solution, as well as a novel povidone-iodine formulation. The presence of biofilm following exposure to the solutions was assessed using both crystal violet (CV) staining and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) viability assay, taking into account the effect of lens case design. Three lens case designs, conventional flat, large bucket type, and cylindrical cases, were investigated for the ability to trap stain and allow biofilm formation.<br><br>RESULTS: Considerable differences were noted between solutions in their ability to prevent and disrupt biofilm (p < 0.001). Lens case design greatly influenced optical density (OD) measurements even in negative controls, as cylindrical cases trapped more stain, increasing OD readings. Correcting for this factor reduced variations, but could not differentiate between residues and biofilm. MTT assay revealed that both povidone-iodine and chlorhexidine-containing solutions could effectively kill > 95% of organisms, whilst PHMB-based solutions were less effective with up to 55% of staphylococci and 41% of Pseudomonas surviving at 24 h.<br><br>CONCLUSION: Biofilm can rapidly form in lens cases and may not be killed by disinfecting solutions. Of the solutions tested, none were able to prevent biofilm formation or disrupt established biofilm, but those containing chlorhexidine or povidone iodine were able to penetrate the biofilm and kill organisms. Assessment of biofilm by CV assay may be confounded by lens case design. Whilst CV assay can demonstrate presence of biofilm, this technique should be accompanied by viability assay to determine bactericidal activity.},
}
@article {pmid31432881,
year = {2019},
author = {Ran, HH and Cheng, X and Bao, YW and Hua, XW and Gao, G and Zhang, X and Jiang, YW and Zhu, YX and Wu, FG},
title = {Multifunctional quaternized carbon dots with enhanced biofilm penetration and eradication efficiencies.},
journal = {Journal of materials chemistry. B},
volume = {7},
number = {33},
pages = {5104-5114},
doi = {10.1039/c9tb00681h},
pmid = {31432881},
issn = {2050-7518},
abstract = {Biofilm formation can lead to the treatment failure of persistent bacterial infections. Although a variety of antibacterial agents have been developed, the restricted drug penetration and the embedded bacteria's potentiated recalcitrance to these agents synergistically lead to the unsatisfactory anti-biofilm effect. Herein, we report the applications of metal-free quaternized carbon dots (CDs) in imaging and eliminating bacterial biofilms. The CDs prepared by the solvothermal treatment of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (abbreviated as Si-QAC) and glycerol possess ultrasmall size (ca. 3.3 ± 0.4 nm) and strong positively charged (zeta potential: ca. +33.1 ± 2.5 mV) surfaces with long alkyl chain-linked quaternary ammonium groups. The small size of the CDs endows them with the penetration ability into the interior of Gram-negative and Gram-positive bacterial biofilms, which enables excellent fluorescence imaging of the biofilms. Due to the different surfaces of the two types of bacteria, the positively charged CDs selectively interact with the more negatively charged Gram-positive bacteria via electrostatic and hydrophobic interactions, which inactivates the Gram-positive bacteria and ultimately eradicates the Gram-positive bacterial biofilms. In addition, we synthesize a new type of quaternized CDs without long alkyl chains (termed TTPAC CDs), and validate that the long alkyl chains potentiate the hydrophobic adhesion between CDs and Gram-positive bacteria. Meanwhile, the crystal violet staining results reveal that the cationic CDs inhibit the formation of Gram-positive bacterial biofilms. Collectively, our work highlights the feasibility of using cationic and ultrasmall metal-free CDs to eliminate and inhibit Gram-positive bacterial biofilms, which represents a highly effective strategy to cope with refractory biofilm-associated infections.},
}
@article {pmid31432051,
year = {2019},
author = {Kuper, NK and Hollanders, ACC and Dekkers, EAM and Maske, TT and Huysmans, MDNJM and Cenci, MS},
title = {Aging Reduces the Anticaries Effect of Antibacterial Adhesive - An In Vitro Biofilm Study.},
journal = {The journal of adhesive dentistry},
volume = {21},
number = {4},
pages = {365-372},
doi = {10.3290/j.jad.a42999},
pmid = {31432051},
issn = {1757-9988},
abstract = {PURPOSE: This in vitro study investigated whether aging different restorative materials influences secondary caries development using a short-term in vitro biofilm model, hypothesizing that the antibacterial adhesive employed may lose its effect over time.<br><br>MATERIALS AND METHODS: Sixty enamel-dentin blocks were divided into 6 groups with n = 10 per group. The groups were restored with three different restorative materials, of which each sample contained an artificial gap: composite with conventional adhesive (CCA; negative control), composite with an antibacterial adhesive (CAA), and amalgam (A; positive control). Half of the groups were prepared fresh and half of the groups were submitted to an aging protocol consisting of water storage, thermocycling, storage in human saliva, and storage in 0.9% saline solution. All specimens were subjected to an intermittent 1% sucrose biofilm model for 20 days to create artificial caries lesions. Lesion progression in the enamel and dentin next to the different materials was measured as lesion depth (LD) and mineral loss (ML), using transverse wavelength independent microradiography (T-WIM). Regression analysis was used to evaluate the effect of aging on LD and ML per restorative material, corrected for gap size.<br><br>RESULTS: In the amalgam group, aging led to shallower lesions and less mineral loss. Fresh amalgam samples showed an average lesion depth of 156.65 ± 39.18 µm at wall dentin locations. Aged amalgam samples had an average lesion depth of 73.42 ± 73.50 µm. Fresh CAA samples showed lower average surface mineral loss values (9104 ± 2631 µm•vol%) than did fresh CCA samples (13166 ± 4769 µm•vol%). After aging, this effect was absent, and the average mineral loss in the CAA group was 13382 ± 5586 µm•vol%, while in the CCA group it was 15518 ± 9283 µm•vol%.<br><br>CONCLUSION: Aging can influence secondary caries development either positively or negatively depending on the kind of restorative material. Antibacterial adhesives may lose their effectiveness over time.},
}
@article {pmid31430670,
year = {2019},
author = {Li, H and Wang, B and Deng, S and Dai, J and Shao, S},
title = {Oxygen-containing functional groups on bioelectrode surface enhance expression of c-type cytochromes in biofilm and boost extracellular electron transfer.},
journal = {Bioresource technology},
volume = {292},
number = {},
pages = {121995},
doi = {10.1016/j.biortech.2019.121995},
pmid = {31430670},
issn = {1873-2976},
abstract = {Introducing oxygen-containing functional groups is a common and convenient method to increase the hydrophilicity of bioelectrodes. In this study, the effect of oxygen-containing functional groups on biofilm was systematically studied to understand how the electron transfer between electrochemically active bacteria (EAB) and bioelectrode was boosted. After electrolysis pretreatment in sulfuric and nitric acid mixture, the oxygen content of the carbon fiber brushes increased from 4.6% to 30.9%. Comparing with the control, the maximum power density increased by 27.7%, while the anode resistance decreased by 21.8%, because charge transfer resistance significantly reduced. The analysis results showed that the content of c-type cytochromes (c-Cyts) in the EAB biofilm was four times higher than that in the control, while the biomass just slightly increased and the bacteria community was similar with that of the control. These findings suggested that the fundamental reason for the enhanced extracellular electron transfer between EAB and electrode was the increased c-Cyts.},
}
@article {pmid31430343,
year = {2019},
author = {Giacomucci, S and Cros, CD and Perron, X and Mathieu-Denoncourt, A and Duperthuy, M},
title = {Flagella-dependent inhibition of biofilm formation by sub-inhibitory concentration of polymyxin B in Vibrio cholerae.},
journal = {PloS one},
volume = {14},
number = {8},
pages = {e0221431},
doi = {10.1371/journal.pone.0221431},
pmid = {31430343},
issn = {1932-6203},
abstract = {Biofilm formation is a common strategy used by bacteria in order to survive and persist in the environment. In Vibrio cholerae (V. cholerae), a Gram-negative pathogen responsible for the cholera disease, biofilm-like aggregates are important for the pathogenesis and disease transmission. Biofilm formation is initiated by the attachment of the bacteria to a surface, followed by maturation stages involving the formation of a biofilm matrix. In V. cholerae, flagella are essential for the initial step of biofilm formation, allowing the bacteria to swim and to detect a surface. In this study, we explored the effect of polymyxin B (PmB), a cationic bacterial antimicrobial peptide, on biofilm formation in pathogenic V. cholerae strains belonging to the O1 and O139 serotypes. We found that sub-inhibitory concentration of PmB induces a reduction of the biofilm formation by V. cholerae O1 and O139. Experiment on preformed biofilm demonstrated that the biofilm formation inhibition occurs at the initial step of biofilm formation, where the flagella are essential. We further characterize the effect of PmB on V. cholerae flagellation. Our results demonstrate that the flagellin expression is not reduced in presence of sub-inhibitory concentration of PmB. However, a decrease of the abundance of flagellin associated with the bacterial cells together with an increase in the secretome was observed. Electron microscopy observations also suggest that the abundance of aflagellated bacteria increases upon PmB supplementation. Finally, in agreement with the effect on the flagellation, a reduction of the bacterial motility is observed. Altogether, our results suggest that the PmB affect V. cholerae flagella resulting in a decrease of the motility and a compromised ability to form biofilm.},
}
@article {pmid31430121,
year = {2019},
author = {Wang, S and Breslawec, AP and Alvarez, E and Tyrlik, M and Li, C and Poulin, MB},
title = {Differential Recognition of Deacetylated PNAG Oligosaccharides by a Biofilm Degrading Glycosidase.},
journal = {ACS chemical biology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acschembio.9b00467},
pmid = {31430121},
issn = {1554-8937},
abstract = {Exopolysaccharides consisting of partially de-N-acetylated poly-β-d-(1→6)-N-acetyl-glucosamine (dPNAG) are key structural components of the biofilm extracellular polymeric substance of both Gram-positive and Gram-negative human pathogens. De-N-acetylation is required for the proper assembly and function of dPNAG in biofilm development suggesting that different patterns of deacetylation may be preferentially recognized by proteins that interact with dPNAG, such as Dispersin B (DspB). The enzymatic degradation of dPNAG by the Aggregatibacter actinomycetemcomitans native β-hexosaminidase enzyme DspB plays a role in biofilm dispersal. To test the role of substrate de-N-acetylation on substrate recognition by DspB, we applied an efficient preactivation-based one-pot glycosylation approach to prepare a panel of dPNAG trisaccharide analogs with defined acetylation patterns. These analogs served as effective DspB substrates, and the rate of hydrolysis was dependent on the specific substrate de-N-acetylation pattern, with glucosamine (GlcN) located +2 from the site of cleavage being preferentially hydrolyzed. The product distributions support a primarily exoglycosidic cleavage activity following a substrate assisted cleavage mechanism, with the exception of substrates containing a nonreducing GlcN that were cleaved endo leading to the exclusive formation of a nonreducing disaccharide product. These observations provide critical insight into the substrate specificity of dPNAG specific glycosidase that can help guide their design as biocatalysts.},
}
@article {pmid31429746,
year = {2019},
author = {Funk, B and Kirmayer, D and Sahar-Heft, S and Gati, I and Friedman, M and Steinberg, D},
title = {Efficacy and potential use of novel sustained release fillers as intracanal medicaments against Enterococcus faecalis biofilm in vitro.},
journal = {BMC oral health},
volume = {19},
number = {1},
pages = {190},
doi = {10.1186/s12903-019-0879-1},
pmid = {31429746},
issn = {1472-6831},
abstract = {BACKGROUND: Enterococcus faecalis is a bacterium frequently isolated after failed root canal therapy. This study analyzed the antibacterial and antibiofilm effects in vitro of sustained-release fillers (SRF) containing cetylpyridinium chloride (CPC) against vancomycin resistant E. faecalis.<br><br>METHODS: First, the solidification capability was tested by introducing liquid SRF into phosphate buffered saline, followed by 30 s of vortexing. The antimicrobial effects of SRF-CPC against static monospecies biofilms were analyzed with a metabolic assay. Inhibition of biofilm formation was tested by exposing daily refreshed E. faecalis suspensions to SRF-CPC for 9 weeks. To evaluate the effects of SRF-CPC against preformed biofilms, biofilms were grown for 1, 3 and 7 days, and then treated with SRF-CPC for 24 h. Biofilm kill time was tested by applying SRF-CPC to a 3-day-old biofilm and measuring its viability at different time points. All experiments were compared to Placebo SRFs and to untreated control biofilms. Data were analyzed with two-way ANOVA followed by Tukey's test. Results were considered significant at P < 0.05.<br><br>RESULTS: The liquid SRF solidified within seconds and no structural changes were observed after 30 s of vortexing at maximum speed. SRF-CPC inhibited E. faecalis biofilm formation for 7 weeks and significantly reduced its viability in weeks 8 and 9. Mature biofilms grown for 1, 3 and 7 days were destructed by SRF-CPC in less than 24 h. Fifty percent of a 3-day-old biofilm was destructed in 2 h and complete destruction occurred in less than 12 h. (P < 0.05 in all cases, compared to SRII-Placebo).<br><br>CONCLUSIONS: SRF-CPC's physical properties and long-lasting anti-biofilm effects make it a promising coadjuvant medication for endodontic therapy.},
}
@article {pmid31429088,
year = {2019},
author = {Brodersen, KE and Koren, K and Revsbech, NP and Kühl, M},
title = {Strong leaf surface basification and CO2 limitation of seagrass induced by epiphytic biofilm microenvironments.},
journal = {Plant, cell &amp; environment},
volume = {},
number = {},
pages = {},
doi = {10.1111/pce.13645},
pmid = {31429088},
issn = {1365-3040},
abstract = {Coastal eutrophication is a growing problem worldwide, leading to increased epiphyte overgrowth of seagrass leaves. Yet, little is known about how epiphytes affect key biogeochemical conditions and processes in the seagrass phyllosphere. We used electrochemical microsensors to measure microgradients of O2 , pH, and CO2 at the bare and epiphyte-covered leaf surface of seagrass (Zostera marina L.) to determine effects of epiphytes on the leaf chemical microenvironment. Epiphytes result in extreme daily fluctuations in pH, O2 and inorganic carbon concentrations at the seagrass leaf surface severely hampering the plant's performance. In light, leaf epiphyte biofilms and their diffusive boundary layer (DBL) lead to strong basification, markedly reducing the CO2 and HCO3- availability at the leaf surface, leading to reduced photosynthetic efficiency as a result of carbon limitation and enhanced photorespiration. With epiphytes, leaf surface pH increased to >10, thereby exceeding final pH levels (~9.62) and CO2 compensation points for active photosynthesis. In darkness, epiphyte biofilms resulted in increased CO2 and hypoxia at the leaf surface. Epiphytes can lead to severe carbon limitation in seagrasses owing to strong phyllosphere basification leading to CO2 depletion and costly, yet limiting, HCO3- utilization, increasing the risk of plant starvation.},
}
@article {pmid31428077,
year = {2019},
author = {Cirri, E and De Decker, S and Bilcke, G and Werner, M and Osuna-Cruz, CM and De Veylder, L and Vandepoele, K and Werz, O and Vyverman, W and Pohnert, G},
title = {Associated Bacteria Affect Sexual Reproduction by Altering Gene Expression and Metabolic Processes in a Biofilm Inhabiting Diatom.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1790},
doi = {10.3389/fmicb.2019.01790},
pmid = {31428077},
issn = {1664-302X},
abstract = {Diatoms are unicellular algae with a fundamental role in global biogeochemical cycles as major primary producers at the base of aquatic food webs. In recent years, chemical communication between diatoms and associated bacteria has emerged as a key factor in diatom ecology, spurred by conceptual and technological advancements to study the mechanisms underlying these interactions. Here, we use a combination of physiological, transcriptomic, and metabolomic approaches to study the influence of naturally co-existing bacteria, Maribacter sp. and Roseovarius sp., on the sexual reproduction of the biofilm inhabiting marine pennate diatom Seminavis robusta. While Maribacter sp. severely reduces the reproductive success of S. robusta cultures, Roseovarius sp. slightly enhances it. Contrary to our expectation, we demonstrate that the effect of the bacterial exudates is not caused by altered cell-cycle regulation prior to the switch to meiosis. Instead, Maribacter sp. exudates cause a reduced production of diproline, the sexual attraction pheromone of S. robusta. Transcriptomic analyses show that this is likely an indirect consequence of altered intracellular metabolic fluxes in the diatom, especially those related to amino acid biosynthesis, oxidative stress response, and biosynthesis of defense molecules. This study provides the first insights into the influence of bacteria on diatom sexual reproduction and adds a new dimension to the complexity of a still understudied phenomenon in natural diatom populations.},
}
@article {pmid31428070,
year = {2019},
author = {Chen, T and Liu, N and Ren, P and Xi, X and Yang, L and Sun, W and Yu, B and Ying, H and Ouyang, P and Liu, D and Chen, Y},
title = {Efficient Biofilm-Based Fermentation Strategies for L-Threonine Production by Escherichia coli.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1773},
doi = {10.3389/fmicb.2019.01773},
pmid = {31428070},
issn = {1664-302X},
abstract = {Biofilms provide cells favorable growth conditions, which have been exploited in industrial biotechnological processes. However, industrial application of the biofilm has not yet been reported in Escherichia coli, one of the most important platform strains, though the biofilm has been extensively studied for pathogenic reasons. Here, we engineered E. coli by overexpressing the fimH gene, which successfully enhanced its biofilm formation under industrial aerobic cultivation conditions. Subsequently, a biofilm-based immobilized fermentation strategy was developed. L-threonine production was increased from 10.5 to 14.1 g/L during batch fermentations and further to 17.5 g/L during continuous (repeated-batch) fermentations with enhanced productivities. Molecular basis for the enhanced biofilm formation and L-threonine biosynthesis was also studied by transcriptome analysis. This study goes beyond the conventional research focusing on pathogenic aspects of E. coli biofilm and represents a successful application case of engineered E. coli biofilm to industrial processes.},
}
@article {pmid31427961,
year = {2019},
author = {Oves, M and Rauf, MA and Hussain, A and Qari, HA and Khan, AAP and Muhammad, P and Rehman, MT and Alajmi, MF and Ismail, IIM},
title = {Antibacterial Silver Nanomaterial Synthesis From Mesoflavibacter zeaxanthinifaciens and Targeting Biofilm Formation.},
journal = {Frontiers in pharmacology},
volume = {10},
number = {},
pages = {801},
doi = {10.3389/fphar.2019.00801},
pmid = {31427961},
issn = {1663-9812},
abstract = {Considering the significance of biological and eco-friendly nanomaterials, in the present study, we have synthesized silver nanoparticles from the exopolysaccharide of recently recovered bacterial strain CEES51 from the Red Sea coastal area of Jeddah, Saudi Arabia. 16S ribosomal RNA gene sequencing was used to characterize the isolated bacteria, and it was identified as Mesoflavibacter zeaxanthinifaciens and assigned an accession number MH707257.1 GenBank. The bacterial strain is an excellent exopolysaccharide producer and survived at hypersaline (30%) and high-temperature (50°C) conditions. The bacterial exopolysaccharides were employed for the fabrication of silver nanoparticles at room temperature. UV-visible spectrophotometer optimized the synthesized nanoparticles, and their size was determined by Nanophox particle size analyzer and dynamic light scattering. Additionally, the X-ray powder diffraction and Fourier-transform infrared spectroscopy studies also approved its crystalline nature and the involvement of organic functional groups in their formation. The synthesized nanomaterials were tested for their antibacterial and antibiofilm properties against pathogenic microorganisms Bacillus subtilis and methicillin-resistant Staphylococcus aureus. The antimicrobial property showed time, and dose-dependent response with a maximum of zone inhibition was observed at around 22 and 18 mm at a dose of 50 µg/well against B. subtilis and S. aureus and a minimum inhibitory concentration of 8 and 10 µg/ml, respectively. Furthermore, the synthesized silver nanoparticles possessed a substantial antibiofilm property and were also found to be biocompatible as depicted by red blood cell lysis assay and their interaction with peripheral blood mononuclear cells and human embryonic kidney 293 cells. Therefore, Mesoflavibacter zeaxanthinifaciens is found to be an excellent source for exopolysaccharide synthesis that assists in the silver nanoparticle production.},
}
@article {pmid31427659,
year = {2019},
author = {Kindler, O and Pulkkinen, O and Cherstvy, AG and Metzler, R},
title = {Burst statistics in an early biofilm quorum sensing model: the role of spatial colony-growth heterogeneity.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {12077},
doi = {10.1038/s41598-019-48525-2},
pmid = {31427659},
issn = {2045-2322},
support = {Humboldt Polish Honorary Research Fellowship//Fundacja na rzecz Nauki Polskiej (Foundation for Polish Science)/ ; ME 1535/7-1//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; },
abstract = {Quorum-sensing bacteria in a growing colony of cells send out signalling molecules (so-called &quot;autoinducers&quot;) and themselves sense the autoinducer concentration in their vicinity. Once-due to increased local cell density inside a &quot;cluster&quot; of the growing colony-the concentration of autoinducers exceeds a threshold value, cells in this clusters get &quot;induced&quot; into a communal, multi-cell biofilm-forming mode in a cluster-wide burst event. We analyse quantitatively the influence of spatial disorder, the local heterogeneity of the spatial distribution of cells in the colony, and additional physical parameters such as the autoinducer signal range on the induction dynamics of the cell colony. Spatial inhomogeneity with higher local cell concentrations in clusters leads to earlier but more localised induction events, while homogeneous distributions lead to comparatively delayed but more concerted induction of the cell colony, and, thus, a behaviour close to the mean-field dynamics. We quantify the induction dynamics with quantifiers such as the time series of induction events and burst sizes, the grouping into induction families, and the mean autoinducer concentration levels. Consequences for different scenarios of biofilm growth are discussed, providing possible cues for biofilm control in both health care and biotechnology.},
}
@article {pmid31427301,
year = {2019},
author = {Bilal, H and Bergen, PJ and Kim, TH and Chung, SE and Peleg, AY and Oliver, A and Nation, RL and Landersdorfer, CB},
title = {Synergistic meropenem-tobramycin combination dosage regimens against clinical hypermutable Pseudomonas aeruginosa at simulated epithelial lining fluid concentrations in a dynamic biofilm model.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01293-19},
pmid = {31427301},
issn = {1098-6596},
abstract = {Exacerbations of chronic Pseudomonas aeruginosa infections are a major treatment challenge in cystic fibrosis due to biofilm formation and hypermutation. We aimed to evaluate different dosage regimens of meropenem and tobramycin in monotherapies and combination against hypermutable carbapenem-resistant P. aeruginosa A hypermutable P. aeruginosa isolate (MICmeropenem and MICtobramycin 8 mg/L) was investigated in the dynamic CDC biofilm reactor over 120 h. Regimens were meropenem as standard (2 g 8-hourly, 30% epithelial lining fluid (ELF) penetration) and continuous infusion (CI, 6 g/day, 30% and 60% ELF penetration), and tobramycin 10 mg/kg 24-hourly (50% ELF penetration). The time-courses of total and less-susceptible bacteria and MICs were determined and antibiotic concentrations quantified by LC-MS/MS. All monotherapies failed with substantial regrowth of planktonic (>6 log10 CFU/mL) and biofilm (≥6 log10 CFU/cm2) bacteria. Except for meropenem CI (60% ELF penetration) all monotherapies amplified less-susceptible planktonic and biofilm bacteria by 120 h. The meropenem standard regimen with tobramycin caused initial killing followed by considerable regrowth with resistance (MICmeropenem 64 mg/L, MICtobramycin 32 mg/L) for planktonic and biofilm bacteria. The combination containing the meropenem CI, at both levels of ELF penetration, synergistically suppressed regrowth of total planktonic bacteria and resistance of planktonic and biofilm bacteria. The combination with meropenem CI at 60% ELF penetration in addition synergistically suppressed regrowth of total biofilm bacteria. Standard regimens of meropenem and tobramycin were ineffective against planktonic and biofilm bacteria. The combination with meropenem CI exhibited enhanced bacterial killing and resistance suppression of carbapenem-resistant hypermutable P. aeruginosa.},
}
@article {pmid31426832,
year = {2019},
author = {Bujold, AR and Lani, NR and Sanz, MG},
title = {Strain-to-strain variation of Rhodococcus equi growth and biofilm formation in vitro.},
journal = {BMC research notes},
volume = {12},
number = {1},
pages = {519},
doi = {10.1186/s13104-019-4560-1},
pmid = {31426832},
issn = {1756-0500},
abstract = {OBJECTIVE: Rhodococcus equi is an opportunistic pathogen that causes disease worldwide in young foals and immunocompromised humans. The interactions of R. equi with the host immune system have been described; however, most studies have been conducted using a few well-characterized strains. Because biological differences between R. equi strains are not well characterized, it is unknown if experimental results will replicate when different strains are used. Therefore, our objective was to compare the growth and biofilm formation of low-passage-rate clinical isolates of R. equi to higher-passage-rate, commonly studied isolates to determine whether strain-to-strain variation exists.<br><br>RESULTS: Twelve strains were used: 103+, ATCC 33701, UKVDL206 103S harboring a GFP-expressing plasmid, a plasmid-cured 33701 (higher-passage-rate) and seven low-passage clinical isolates. Generation time in liquid revealed fast, moderate-fast, moderate-slow, and slow-growing isolates. The higher-passage-rate isolates were among the moderate-slow growing strains. A strain's rate of growth did not correspond to its ability to form biofilm nor to its colony size on solid media. Based on our results, care should be taken not to extrapolate in vitro work that may be conducted using different R. equi strains. Further work is needed to evaluate the effect that the observed differences may have on experimental results.},
}
@article {pmid31424553,
year = {2019},
author = {Soares, A and Alexandre, K and Lamoureux, F and Lemée, L and Caron, F and Pestel-Caron, M and Etienne, M},
title = {Efficacy of a ciprofloxacin/amikacin combination against planktonic and biofilm cultures of susceptible and low-level resistant Pseudomonas aeruginosa.},
journal = {The Journal of antimicrobial chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1093/jac/dkz355},
pmid = {31424553},
issn = {1460-2091},
abstract = {BACKGROUND: Eradicating bacterial biofilm without mechanical dispersion remains a challenge. Combination therapy has been suggested as a suitable strategy to eradicate biofilm.<br><br>OBJECTIVES: To evaluate the efficacy of a ciprofloxacin/amikacin combination in a model of in vitro Pseudomonas aeruginosa biofilm.<br><br>METHODS: The antibacterial activity of ciprofloxacin and amikacin (alone, in combination and successively) was evaluated by planktonic and biofilm time-kill assays against five P. aeruginosa strains: PAO1, a WT clinical strain and three clinical strains overexpressing the efflux pumps MexAB-OprM (AB), MexXY-OprM (XY) and MexCD-OprJ (CD), respectively. Amikacin MIC was 16 mg/L for XY and ciprofloxacin MIC was 0.5 mg/L for CD. The other strains were fully susceptible to ciprofloxacin and amikacin. The numbers of total and resistant cells were determined.<br><br>RESULTS: In planktonic cultures, regrowth of high-level resistant mutants was observed when CD was exposed to ciprofloxacin alone and XY to amikacin alone. Eradication was obtained with ciprofloxacin or amikacin in the other strains, or with the combination in XY and CD strains. In biofilm, bactericidal reduction after 8 h followed by a mean 4 log10 cfu/mL plateau in all strains and for all regimens was noticed. No regrowth of resistant mutants was observed whatever the antibiotic regimen. The bacterial reduction obtained with a second antibiotic used simultaneously or consecutively was not significant.<br><br>CONCLUSIONS: The ciprofloxacin/amikacin combination prevented the emergence of resistant mutants in low-level resistant strains in planktonic cultures. Biofilm persister cells were not eradicated, either with monotherapy or with the combination.},
}
@article {pmid31423363,
year = {2019},
author = {Payette, G and Geoffroy, V and Martineau, C and Villemur, R},
title = {Dynamics of a methanol-fed marine denitrifying biofilm: 1-Impact of environmental changes on the denitrification and the co-occurrence of Methylophaga nitratireducenticrescens and Hyphomicrobium nitrativorans.},
journal = {PeerJ},
volume = {7},
number = {},
pages = {e7497},
doi = {10.7717/peerj.7497},
pmid = {31423363},
issn = {2167-8359},
abstract = {Background: The biofilm of a methanol-fed denitrification system that treated a marine effluent is composed of multi-species microorganisms, among which Hyphomicrobium nitrativorans strain NL23 and Methylophaga nitratireducenticrescens strain JAM1 are the principal bacteria involved in the denitrifying activities. Here, we report the capacity of the denitrifying biofilm to sustain environmental changes, and the impact of these changes on the co-occurrence of H. nitrativorans and M. nitratireducenticrescens.<br><br>Methods: In a first set of assays, the original biofilm (OB) was cultivated in an artificial seawater (ASW) medium under anoxic conditions to colonize new carriers. The new formed biofilm was then subjected to short exposures (1-5 days) of a range of NaCl, methanol, nitrate (NO3-) and nitrite (NO2-) concentrations, and to different pHs and temperatures. In a second set of assays, the OB was cultivated in ASW medium for five weeks with (i) a range of NaCl concentrations, (ii) four combinations of NO3-/methanol concentrations and temperatures, (iii) NO2-, and (iv) under oxic conditions. Finally, the OB was cultivated for five weeks in the commercial Instant Ocean (IO) seawater. The growth of the biofilm and the dynamics of NO3- and NO2- were determined. The levels of M. nitratireducenticrescens and H. nitrativorans were measured by qPCR.<br><br>Results: In the first set of assays, the biofilm cultures had the capacity to sustain denitrifying activities in most of the tested conditions. Inhibition occurred when they were exposed to high pH (10) or to high methanol concentration (1.5%). In the second set of assays, the highest specific denitrification rates occurred with the biofilm cultures cultivated at 64.3 mM NO3- and 0.45% methanol, and at 30 °C. Poor biofilm development occurred with the biofilm cultures cultivated at 5% and 8% NaCl. In all biofilm cultures cultivated in ASW at 2.75% NaCl, H. nitrativorans strain NL23 decreased by three orders of magnitude in concentrations compared to that found in OB. This decrease coincided with the increase of the same magnitude of a subpopulation of M. nitratireducenticrescens (strain GP59 as representative). In the biofilm cultures cultivated at low NaCl concentrations (0% to 1.0%), persistence of H. nitrativorans strain NL23 was observed, with the gradual increase in concentrations of M. nitratireducenticrescens strain GP59. High levels of H. nitrativorans strain NL23 were found in the IO biofilm cultures. The concentrations of M. nitratireducenticrescens strain JAM1 were lower in most of the biofilms cultures than in OB.<br><br>Conclusions: These results demonstrate the plasticity of the marine methylotrophic denitrifying biofilm in adapting to different environmental changes. The NaCl concentration is a crucial factor in the dynamics of H. nitrativorans strain NL23, for which growth was impaired above 1% NaCl in the ASW-based biofilm cultures in favor of M. nitratireducenticrescens strain GP59.},
}
@article {pmid31423359,
year = {2019},
author = {Villemur, R and Payette, G and Geoffroy, V and Mauffrey, F and Martineau, C},
title = {Dynamics of a methanol-fed marine denitrifying biofilm: 2-impact of environmental changes on the microbial community.},
journal = {PeerJ},
volume = {7},
number = {},
pages = {e7467},
doi = {10.7717/peerj.7467},
pmid = {31423359},
issn = {2167-8359},
abstract = {Background: The biofilm of a methanol-fed, marine denitrification system is composed of a multi-species microbial community, among which Hyphomicrobium nitrativorans and Methylophaga nitratireducenticrescens are the principal bacteria involved in the denitrifying activities. To assess its resilience to environmental changes, the biofilm was cultivated in artificial seawater (ASW) under anoxic conditions and exposed to a range of specific environmental conditions. We previously reported the impact of these changes on the denitrifying activities and the co-occurrence of H. nitrativorans strain NL23 and M. nitratireducenticrescens in the biofilm cultures. Here, we report the impact of these changes on the dynamics of the overall microbial community of the denitrifying biofilm.<br><br>Methods: The original biofilm (OB) taken from the denitrification system was cultivated in ASW under anoxic conditions with a range of NaCl concentrations, and with four combinations of nitrate/methanol concentrations and temperatures. The OB was also cultivated in the commercial Instant Ocean seawater (IO). The bacterial diversity of the biofilm cultures and the OB was determined by 16S ribosomal RNA gene sequences. Culture approach was used to isolate other denitrifying bacteria from the biofilm cultures. The metatranscriptomes of selected biofilm cultures were derived, along with the transcriptomes of planktonic pure cultures of H. nitrativorans strain NL23 and M. nitratireducenticrescens strain GP59.<br><br>Results: High proportions of M. nitratireducenticrescens occurred in the biofilm cultures. H. nitrativorans strain NL23 was found in high proportion in the OB, but was absent in the biofilm cultures cultivated in the ASW medium at 2.75% NaCl. It was found however in low proportions in the biofilm cultures cultivated in the ASW medium at 0-1% NaCl and in the IO biofilm cultures. Denitrifying bacterial isolates affiliated to Marinobacter spp. and Paracoccus spp. were isolated. Up regulation of the denitrification genes of strains GP59 and NL23 occurred in the biofilm cultures compared to the planktonic pure cultures. Denitrifying bacteria affiliated to the Stappia spp. were metabolically active in the biofilm cultures.<br><br>Conclusions: These results illustrate the dynamics of the microbial community in the denitrifying biofilm cultures in adapting to different environmental conditions. The NaCl concentration is an important factor affecting the microbial community in the biofilm cultures. Up regulation of the denitrification genes of M. nitratireducenticrescens strain GP59 and H. nitrativorans strain NL23 in the biofilm cultures suggests different mechanisms of regulation of the denitrification pathway in the biofilm. Other denitrifying heterotrophic bacteria are present in low proportions, suggesting that the biofilm has the potential to adapt to heterotrophic, non-methylotrophic environments.},
}
@article {pmid31421719,
year = {2019},
author = {Velmourougane, K and Prasanna, R and Supriya, P and Ramakrishnan, B and Thapa, S and Saxena, AK},
title = {Transcriptome profiling provides insights into regulatory factors involved in Trichoderma viride-Azotobacter chroococcum biofilm formation.},
journal = {Microbiological research},
volume = {227},
number = {},
pages = {126292},
doi = {10.1016/j.micres.2019.06.002},
pmid = {31421719},
issn = {1618-0623},
abstract = {Azotobacter chroococcum (Az) and Trichoderma viride (Tv) represent agriculturally important and beneficial plant growth promoting options which contribute towards nutrient management and biocontrol, respectively. When Az and Tv are co-cultured, they form a biofilm, which has proved promising as an inoculant in several crops; however, the basic aspects related to regulation of biofilm formation were not investigated. Therefore, whole transcriptome sequencing (Illumina NextSeq500) and gene expression analyses were undertaken, related to biofilm formation vis a vis Tv and Az growing individually. Significant changes in the transcriptome profiles of biofilm were recorded and validated through qPCR analyses. In-depth evaluation also identified several genes (phoA, phoB, glgP, alg8, sipW, purB, pssA, fadD) specifically involved in biofilm formation in Az, Tv and Tv-Az. Genes coding for RNA-dependent RNA polymerase, ABC transporters, translation elongation factor EF-1, molecular chaperones and double homeobox 4 were either up-regulated or down-regulated during biofilm formation. To our knowledge, this is the first report on the modulation of gene expression in an agriculturally beneficial association, as a biofilm. Our results provide insights into the regulatory factors involved during biofilm formation, which can help to improve the beneficial effects and develop more effective and promising plant- microbe associations.},
}
@article {pmid31421577,
year = {2019},
author = {Song, W and Qi, R and Zhao, L and Xue, N and Wang, L and Yang, Y},
title = {Bacterial community rather than metals shaping metal resistance genes in water, sediment and biofilm in lakes from arid northwestern China.},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {254},
number = {Pt A},
pages = {113041},
doi = {10.1016/j.envpol.2019.113041},
pmid = {31421577},
issn = {1873-6424},
abstract = {Lakes in arid northwestern China are valuable freshwater resources that drive socioeconomic development. Environmental pollution can significantly influence the composition of microbial communities and the distribution of functional genes in lakes. This study investigated heavy metal pollution to identify possible correlations with metal resistance genes (MRGs) and bacterial community composition in water, sediment and biofilm samples from Bosten Lake and Ebi Lake in northwestern China. High levels of zinc were detected in all samples. However, the metals detected in the sediment samples of both lakes were determined to be at low risk levels according to an ecological index. The mercury resistance gene subtype merP had the greatest average abundance (4.61 × 10-3 copies per 16S rRNA) among all the samples, followed by merA and merC. The high abundance of merA in the pelagic zone rather than in benthic sediment suggests that the pelagic microbial community was important in mercury reduction. Proteobacteria were the main phylum found in the microbial communities in all samples. However, microbial communities in most of the water, sediment and biofilm samples had different compositions, indicating that the habitat niche plays an important role in shaping the bacterial communities in lakes. The microbial community, rather than the heavy metals, was the main driver of MRG distribution. The abundances of some bacterial genera involved in the decomposition of organic matter and the terrestrial nitrogen cycle were negatively correlated with heavy metals. This result suggests that metal pollution can adversely affect the biogeochemical processes that occur in lakes.},
}
@article {pmid31421576,
year = {2019},
author = {Lukwambe, B and Zhao, L and Nicholaus, R and Yang, W and Zhu, J and Zheng, Z},
title = {Bacterioplankton community in response to biological filters (clam, biofilm, and macrophytes) in an integrated aquaculture wastewater bioremediation system.},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {254},
number = {Pt A},
pages = {113035},
doi = {10.1016/j.envpol.2019.113035},
pmid = {31421576},
issn = {1873-6424},
abstract = {Integrated systems with appropriate bio-filters can be used to treat aquaculture effluents. However, the information on bio-filters that alters the ecological functions of the bacterioplankton community (BC) in biodegradation of the aquaculture effluents remains controversial. In this study, we implemented a comprehensive restoration technology combined with bio-filters [biofilm, clam (Tegillarca granosa), and macrophytes (Spartina anglica)] to investigate their influence on the stability of the BC and nutrient removal. We found that the diversity of BC was linked with biogeochemical factors in processing and upcycling nitrogen-rich effluents into high-value biomass. The BC exhibited significant distinct patterns in the bio-filter areas. Potential biomarkers for constrained harmfully algae-bacteria (Nitriliruptoraceae, Bacillales, and Rhodobacteraceae) and nutrient removal were significantly higher in the bio-filters areas. The bio-filters significantly promoted the restoration effects of N and P balance by reducing 82.34% of total nitrogen (TN) and 81.64% of total phosphorus (TP) loads at the water interface. The main mechanisms for TN and TP removal and nutrient transformation were achieved by assimilation and absorption by the emergent macrophytes (Spartina anglica). The bio-filters significantly influenced the biodegradability and resolvability of particulate organic matter through ammonification, nitrification, and denitrification of microbes, which meliorated the nutrient removal. Beside bio-filter effects, the BC was significantly controlled by abiotic factors [nitrate (NO3--N), dissolved oxygen (DO), total nitrogen (TN), and water temperature (WT)], and biotic factors (chlorophyll ɑ and green algae). Our study revealed that the co-existence system with bio-filters may greatly improve our understanding on the ecological functions of the BC in aquaculture systems. Overall, combined bio-filters provide an opportunity for the development of efficient and optimized aquaculture wastewater treatment technology.},
}
@article {pmid31421403,
year = {2019},
author = {Martín, ML and Dassie, SA and Valenti, LE and Giacomelli, CE},
title = {A simple surface biofunctionalization strategy to inhibit the biofilm formation by Staphylococcus aureus on solid substrates.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {183},
number = {},
pages = {110432},
doi = {10.1016/j.colsurfb.2019.110432},
pmid = {31421403},
issn = {1873-4367},
abstract = {Staphylococcus aureus is an important opportunistic pathogen that causes a broad range of infections due to the bacteria capacity to form biofilms on medical devices. This work is aimed at inhibiting the biofilm formation by S. aureus on solid substrates using a simple surface biofunctionalization strategy. We previously found that surface biofunctionalization with structural perturbed albumin inhibited the initial stage of S. aureus adhesion. The current work extends this strategy with other plasma protein, fibrinogen, which in addition can be bond specifically to the cell wall-anchored proteins of S. aureus. The study of fibrinogen adsorption indicates that the fraction of surface-perturbed molecules is enlarged at long adsorption times and low protein concentration. In these conditions, a significant diminution of ca.60% of alive adhered bacteria were observed after 40 min and the biofilm formation was completely prevented. Thus, it seems that the inhibition of bacterial adhesion on substrates with surface-perturbed proteins represents a general trend even when specific interactions are present. On this basis, we developed a simple strategy to inhibit the formation of S. aureus biofilm, using thermally treated albumin or fibrinogen molecules prior to the substrate biofunctionalization. This strategy shows an excellent performance since the alive adhered bacteria diminishes ca. 90% at short incubation time, followed by the fully inhibition of biofilm formation. This novel and simple resource represents a change of the usual notion in avoiding post-surgery infections, mostly related to the use of medical devices.},
}
@article {pmid31420537,
year = {2019},
author = {Qin, Y and He, Y and She, Q and Larese-Casanova, P and Li, P and Chai, Y},
title = {Heterogeneity in respiratory electron transfer and adaptive iron utilization in a bacterial biofilm.},
journal = {Nature communications},
volume = {10},
number = {1},
pages = {3702},
doi = {10.1038/s41467-019-11681-0},
pmid = {31420537},
issn = {2041-1723},
support = {MCB1651732//National Science Foundation (NSF)/ ; },
abstract = {In Bacillus subtilis, robust biofilm formation requires large quantities of ferric iron. Here we show that this process requires preferential production of a siderophore precursor, 2,3-dihydroxybenzoate, instead of the siderophore bacillibactin. A large proportion of iron is associated extracellularly with the biofilm matrix. The biofilms are conductive, with extracellular iron potentially acting as electron acceptor. A relatively small proportion of ferric iron is internalized and boosts production of iron-containing enzymes involved in respiratory electron transfer and establishing strong membrane potential, which is key to biofilm matrix production. Our study highlights metabolic diversity and versatile energy generation strategies within B. subtilis biofilms.},
}
@article {pmid31420126,
year = {2019},
author = {Fulaz, S and Vitale, S and Quinn, L and Casey, E},
title = {Nanoparticle-Biofilm Interactions: The Role of the EPS Matrix.},
journal = {Trends in microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.tim.2019.07.004},
pmid = {31420126},
issn = {1878-4380},
abstract = {The negative consequences of biofilms are widely reported. A defining feature of biofilms is the extracellular matrix, a complex mixture of biomacromolecules, termed EPS, which contributes to reduced antimicrobial susceptibility. EPS targeting is a promising, but underexploited, approach to biofilm control allowing disruption of the matrix and thereby increasing the susceptibility to antimicrobials. Nanoparticles (NPs) can play a very important role as 'carriers' of EPS matrix disruptors, and several approaches have recently been proposed. In this review, we discuss the application of nanoparticles as antibiofilm technologies with a special emphasis on the role of the EPS matrix in the physicochemical regulation of the nanoparticle-biofilm interaction. We highlight the use of nanoparticles as a platform for a new generation of antibiofilm approaches.},
}
@article {pmid31419460,
year = {2019},
author = {Miryala, SK and Anbarasu, A and Ramaiah, S},
title = {Systems biology studies in Pseudomonas aeruginosa PA01 to understand their role in biofilm formation and multidrug efflux pumps.},
journal = {Microbial pathogenesis},
volume = {136},
number = {},
pages = {103668},
doi = {10.1016/j.micpath.2019.103668},
pmid = {31419460},
issn = {1096-1208},
abstract = {The antimicrobial resistance (AMR) exhibited against broad spectrum and new generation antibiotics used for Pseudomonas infections is a major threat and renders the treatment ineffective. In our present study, we have used a computational approach to understand various drug resistance mechanisms which contribute to Multi-Drug Resistance (MDR) in P. aeruginosa. The interaction network of 60 AMR genes along with the 337 functional interactions was analyzed. Functional enrichment analysis of AMR genes has shown that the genes in the network are mainly associated with efflux pump mechanisms, alginate biosynthesis, biofilm formation, and ampC beta-lactamase biosynthesis. Interestingly, the genes phoP, phoQ, and cat genes are observed to have roles in more than one drug-resistant mechanism. The genes phoP and phoQ apart from their role in two-component regulatory systems also play major roles in multidrug efflux pumps and alteration in drug target. The gene cat involves in alteration of drug target and enzymatic inactivation. The interaction network analysis has shown that the AMR genes oprJ, oprM, oprN, ampC, gyrA, mexA, oprD, mexB and nfxB have higher number of direct interactors and they are considered as the hub nodes in the network and these genes can be used as potential drug targets for developing new drugs. The results from our study will be helpful in better understanding of the antibiotic resistance mechanisms in P. aeruginosa. The gene targets reported, can be used for new drug discovery against Pseudomonas infections.},
}
@article {pmid31413280,
year = {2019},
author = {Inui, T and Palmer, RJ and Shah, N and Li, W and Cisar, JO and Wu, CD},
title = {Effect of mechanically stimulated saliva on initial human dental biofilm formation.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {11805},
doi = {10.1038/s41598-019-48211-3},
pmid = {31413280},
issn = {2045-2322},
support = {Intramural Research Program//U.S. Department of Health &amp; Human Services | NIH | National Institute of Dental and Craniofacial Research (NIDCR)/ ; NA//Mars Incorporated | Wm. Wrigley Jr. Company (Wrigley Company)/ ; },
abstract = {This study evaluated the impact of mechanically stimulated saliva on initial bacterial colonization. Interaction between oral bacteria and both unstimulated and stimulated saliva was examined in vitro by laying labeled bacteria over SDS-PAGE-separated salivary proteins. The effects of chewing on in vivo biofilm, microbial composition, and spatial arrangement were examined in two human volunteers using an intraoral stent containing retrievable enamel chips. In vitro experiments showed that bacterial binding to proteins from stimulated saliva was lower than that to proteins from unstimulated saliva. Lack of binding activity was noted with Streptococcus mutans and Lactobacillus casei. Human Oral Microbe Identification Microarray (HOMIM) analyses revealed a consistent chewing-related increase in the binding of Streptococcus anginosus and Streptococcus gordonii. Immunofluorescence microscopy demonstrated the presence of multi-species colonies and cells bearing different serotypes of the coaggregation-mediating streptococcal cell-surface receptor polysaccharides (RPS). Differences in bacterial colonization were noted between the two volunteers, while the type 4 RPS-reactive serotype was absent in one volunteer. Cells reacting with antibody against Rothia or Haemophilus were prominent in the early biofilm. While analysis of the data obtained demonstrated inter-individual variations in both in vitro and in vivo bacterial binding patterns, stimulating saliva with multiple orosensory stimuli may modulate oral bacterial colonization of tooth surfaces.},
}
@article {pmid31412645,
year = {2019},
author = {Magin, V and Garrec, N and Andrés, Y},
title = {Selection of Bacteriophages to Control In Vitro 24 h Old Biofilm of Pseudomonas Aeruginosa Isolated from Drinking and Thermal Water.},
journal = {Viruses},
volume = {11},
number = {8},
pages = {},
doi = {10.3390/v11080749},
pmid = {31412645},
issn = {1999-4915},
abstract = {Pseudomonas aeruginosa is an opportunistic pathogen that causes public healthcare issues. In moist environments, this Gram-negative bacterium persists through biofilm-associated contamination on surfaces. Bacteriophages are seen as a promising alternative strategy to chemical biocides. This study evaluates the potential of nine lytic bacteriophages as biocontrol treatments against nine environmental P. aerginosa isolates. The spot test method is preliminarily used to define the host range of each virus and to identify their minimum infectious titer, depending on the strain. Based on these results, newly isolated bacteriophages 14.1, LUZ7, and B1 are selected and assessed on a planktonic cell culture of the most susceptible isolates (strains MLM, D1, ST395E, and PAO1). All liquid infection assays are achieved in a mineral minimum medium that is much more representative of real moist environments than standard culture medium. Phages 14.1 and LUZ7 eliminate up to 90% of the PAO1 and D1 bacterial strains. Hence, their effectiveness is evaluated on the 24 h old biofilms of these strains, established on a stainless steel coupon that is characteristic of materials found in thermal and industrial environments. The results of quantitative PCR viability show a maximum reduction of 1.7 equivalent Log CFU/cm2 in the coupon between treated and untreated surfaces and shed light on the importance of considering the entire virus/host/environment system for optimizing the treatment.},
}
@article {pmid31411265,
year = {2019},
author = {Yu, MK and Kim, MA and Rosa, V and Hwang, YC and Del Fabbro, M and Sohn, WJ and Min, KS},
title = {Role of extracellular DNA in Enterococcus faecalis biofilm formation and its susceptibility to sodium hypochlorite.},
journal = {Journal of applied oral science : revista FOB},
volume = {27},
number = {},
pages = {e20180699},
doi = {10.1590/1678-7757-2018-0699},
pmid = {31411265},
issn = {1678-7765},
mesh = {Animals ; Biofilms/*drug effects/*growth &amp; development ; Cattle ; Colony Count, Microbial ; DNA, Bacterial/*pharmacology ; Dental Pulp Cavity/microbiology ; Deoxyribonucleases/*pharmacology ; Enterococcus faecalis/*drug effects/*growth &amp; development ; Microbial Sensitivity Tests ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Polysaccharides, Bacterial/isolation &amp; purification ; Reproducibility of Results ; Sodium Hypochlorite/*pharmacology ; Time Factors ; },
abstract = {OBJECTIVE: This study investigated the role of extracellular deoxyribonucleic acid (eDNA) on Enterococcus faecalis (E. faecalis) biofilm and the susceptibility of E. faecalis to sodium hypochlorite (NaOCl).<br><br>METHODOLOGY: E. faecalis biofilm was formed in bovine tooth specimens and the biofilm was cultured with or without deoxyribonuclease (DNase), an inhibitor of eDNA. Then, the role of eDNA in E. faecalis growth and biofilm formation was investigated using colony forming unit (CFUs) counting, eDNA level assay, crystal violet staining, confocal laser scanning microscopy, and scanning electron microscopy. The susceptibility of E. faecalis biofilm to low (0.5%) or high (5%) NaOCl concentrations was also analyzed by CFU counting.<br><br>RESULTS: CFUs and biofilm formation decreased significantly with DNase treatment (p<0.05). The microstructure of DNase-treated biofilms exhibited less structured features when compared to the control. The volume of exopolysaccharides in the DNase-treated biofilm was significantly lower than that of control (p<0.05). Moreover, the CFUs, eDNA level, biofilm formation, and exopolysaccharides volume were lower when the biofilm was treated with DNase de novo when compared to when DNase was applied to matured biofilm (p<0.05). E. faecalis in the biofilm was more susceptible to NaOCl when it was cultured with DNase (p<0.05). Furthermore, 0.5% NaOCl combined with DNase treatment was as efficient as 5% NaOCl alone regarding susceptibility (p>0.05).<br><br>CONCLUSIONS: Inhibition of eDNA leads to decrease of E. faecalis biofilm formation and increase of susceptibility of E. faecalis to NaOCl even at low concentrations. Therefore, our results suggest that inhibition of eDNA would be beneficial in facilitating the efficacy of NaOCl and reducing its concentration.},
}
@article {pmid31410982,
year = {2019},
author = {Petrovich, ML and Ben Maamar, S and Hartmann, EM and Murphy, BT and Poretsky, RS and Wells, GF},
title = {Viral composition and context in metagenomes from biofilm and suspended growth municipal wastewater treatment plants.},
journal = {Microbial biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1751-7915.13464},
pmid = {31410982},
issn = {1751-7915},
support = {C-060//Chicago Biomedical Consortium/ ; //Northwestern University/ ; //Searle Funds at The Chicago Community Trust/ ; },
abstract = {Wastewater treatment plants (WWTPs) contain high density and diversity of viruses which can significantly impact microbial communities in aquatic systems. While previous studies have investigated viruses in WWTP samples that have been specifically concentrated for viruses and filtered to exclude bacteria, little is known about viral communities associated with bacterial communities throughout wastewater treatment systems. Additionally, differences in viral composition between attached and suspended growth wastewater treatment bioprocesses are not well characterized. Here, shotgun metagenomics was used to analyse wastewater and biomass from transects through two full-scale WWTPs for viral composition and associations with bacterial hosts. One WWTP used a suspended growth activated sludge bioreactor and the other used a biofilm reactor (trickling filter). Myoviridae, Podoviridae and Siphoviridae were the dominant viral families throughout both WWTPs, which are all from the order Caudovirales. Beta diversity analysis of viral sequences showed that samples clustered significantly both by plant and by specific sampling location. For each WWTP, the overall bacterial community structure was significantly different than community structure of bacterial taxa associated with viral sequences. These findings highlight viral community composition in transects through different WWTPs and provide context for dsDNA viral sequences in bacterial communities from these systems.},
}
@article {pmid31410606,
year = {2019},
author = {Wang, Z and Shi, LD and Lai, CY and Zhao, HP},
title = {Methane oxidation coupled to vanadate reduction in a membrane biofilm batch reactor under hypoxic condition.},
journal = {Biodegradation},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10532-019-09887-6},
pmid = {31410606},
issn = {1572-9729},
support = {LR17B070001//Natural Science Funds for Distinguished Young Scholar of Zhejiang Province/ ; 21577123//National Natural Science Foundation of China/ ; 51878596//National Natural Science Foundation of China/ ; 2018YFC1802203//National Key Technology R&amp;D Program/ ; },
abstract = {This study shows vanadate (V(V)) reduction in a methane (CH4) based membrane biofilm batch reactor when the concentration of dissolved oxygen (O2) was extremely low. V(IV) was the dominant products formed from V(V) bio-reduction, and majority of produced V(IV) transformed into precipitates with green color. Quantitative polymerase chain reaction and Illumina sequencing analysis showed that archaea methanosarcina were significantly enriched. Metagenomic predictive analysis further showed the enrichment of genes associated with reverse methanogenesis pathway, the key CH4-activating mechanism for anaerobic methane oxidation (AnMO), as well as the enrichment of genes related to acetate synthesis, in archaea. The enrichment of aerobic methanotrophs Methylococcus and Methylomonas implied their role in CH4 activation using trace level of O2, or their participation in V(V) reduction.},
}
@article {pmid31410037,
year = {2019},
author = {Bidossi, A and Bottagisio, M and De Grandi, R and Drago, L and De Vecchi, E},
title = {Chlorquinaldol, a topical agent for skin and wound infections: anti-biofilm activity and biofilm-related antimicrobial cross-resistance.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {2177-2189},
doi = {10.2147/IDR.S211007},
pmid = {31410037},
issn = {1178-6973},
abstract = {Purpose: Persistence of skin and wound infections is nowadays accepted being linked to bacterial biofilms, which are highly recalcitrant to treatments and contribute to maintain a constant inflammation state and prevent a correct healing. Topical antimicrobials are the most common first-line self-medications; however, treatment failure is not uncommon and emerging resistance to antibiotics is alarming. Chlorquinaldol is an antimicrobial with a wide spectrum of activity and desirable characteristics for topical application. Aim of this study was to evaluate the efficacy of chlorquinaldol to prevent or eradicate S. aureus and P. aeruginosa biofilms, in comparison to classic topical antibiotics like gentamicin and fusidic acid.<br><br>Methods: Minimum inhibitory concentrations (MIC) were assessed for each strain and subinhibitory concentrations (½ and ¼ MIC) were used in the biofilm assay. Antimicrobial assays were performed during biofilm formation or were applied on mature biofilms and were evaluated by means of crystal violet assay and confocal laser scan microscopy.<br><br>Results: Chlorquinaldol and gentamicin were the most effective antimicrobials in both eradicating and preventing pathogens biofilm; however, resistance to methicillin and impermeability to carbapenems impaired chlorquinaldol effect. In addition, similarly to other hydroxyquinolines, aspecific metal chelation is here proposed as chlorquinaldol mode of action.<br><br>Conclusion: Relying on an acceptable antibiofilm and a wide spectrum of activity, an aspecific mode of action and consequent absence of resistance development, chlorquinaldol proved to be a good antimicrobial for topical use.},
}
@article {pmid31409687,
year = {2019},
author = {Jung, YC and Lee, MA and Lee, KH},
title = {Role of Flagellin-Homologous Proteins in Biofilm Formation by Pathogenic Vibrio Species.},
journal = {mBio},
volume = {10},
number = {4},
pages = {},
doi = {10.1128/mBio.01793-19},
pmid = {31409687},
issn = {2150-7511},
abstract = {The pathogenic bacterium Vibrio vulnificus exhibits the ability to form biofilm, for which initiation is dependent upon swimming motility by virtue of a polar flagellum. The filament of its flagellum is composed of multiple flagellin subunits, FlaA, -B, -C, and -D. In V. vulnificus genomes, however, open reading frames (ORFs) annotated by FlaE and -F are also present. Although neither FlaE nor FlaF is involved in filament formation and cellular motility, they are well expressed and secreted to the extracellular milieu through the secretion apparatus for flagellar assembly. In the extrapolymeric matrix of V. vulnificus biofilm, significant levels of FlaEF were detected. Mutants defective in both flaE and flaF formed significantly decreased biofilms compared to the wild-type biofilm. Thus, the potential role of FlaEF during the biofilm-forming process was investigated by exogenous addition of recombinant FlaEF (rFlaEF) to the biofilm assays. The added rFlaE and rFlaF were predominantly incorporated into the biofilm matrix formed by the wild type. However, biofilms formed by a mutant defective in exopolysaccharide (EPS) biosynthesis were not affected by added FlaEF. These results raised a possibility that FlaEF specifically interact with EPS within the biofilm matrix. In vitro pulldown assays using His-tagged rFlaEF or rFlaC revealed the specific binding of EPS to rFlaEF but not to rFlaC. Taken together, our results demonstrate that V. vulnificus FlaEF, flagellin-homologous proteins (FHPs), are crucial for biofilm formation by directly interacting with the essential determinant for biofilm maturation, EPS. Further analyses performed with other pathogenic Vibrio species demonstrated both the presence of FHPs and their important role in biofilm formation.IMPORTANCE Flagellar filaments of the pathogenic Vibrio species, including V. vulnificus, V. parahaemolyticus, and V. cholerae, are composed of multiple flagellin subunits. In their genomes, however, there are higher numbers of the ORFs encoding flagellin-like proteins than the numbers of flagellin subunits required for filament assembly. Since these flagellin-homologous proteins (FHPs) are well expressed and excreted to environments via a flagellin transport channel, their extracellular role in the pathogenic Vibrio has been enigmatic. Their biological significance, which is not related with flagellar functions, has been revealed to be in maturation of biofilm structures. Among various components of the extracellular polymeric matrix produced in the V. vulnificus biofilms, the exopolysaccharides (EPS) are dominant constituents and crucial in maturation of biofilms. The enhancing role of the V. vulnificus FHPs in biofilm formation requires the presence of EPS, as indicated by highly specific interactions among two FHPs and three EPS.},
}
@article {pmid31408199,
year = {2019},
author = {Ali, IAA and Cheung, BPK and Yau, JYY and Matinlinna, JP and Lévesque, CM and Belibasakis, GN and Neelakantan, P},
title = {The influence of substrate surface conditioning and biofilm age on the composition of Enterococcus faecalis biofilms.},
journal = {International endodontic journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/iej.13202},
pmid = {31408199},
issn = {1365-2591},
support = {201702159011//University Research Committee, University of Hong Kong/ ; },
abstract = {AIM: To investigate the null hypothesis that neither the surface conditioning (collagen, serum, saliva) of hydroxyapatite (HA) discs, nor the biofilm age (3 days vs. 21 days) has a significant effect on the cellular and matrix composition of biofilms, using Enterococcus faecalis as the model organism.<br><br>METHODOLOGY: Sterile HA discs were conditioned with collagen, saliva or serum, and inoculated with E. faecalis to form 3-day and 21-day-old biofilms. Unconditioned discs served as controls. The biofilms were analysed using culture-dependent and independent (confocal microscopy and biochemical analysis) methods, to determine the colony-forming units and the biofilm matrix composition (polysaccharides and proteins), respectively. Statistical analyses were performed using appropriate parametric and nonparametric tests (P = 0.05).<br><br>RESULTS: Collagen conditioning significantly increased the number of CFUs in the 21-day biofilms, compared to the 3-day biofilms (P < 0.05). Although the biochemical analysis revealed that surface conditioning had no significant effect on the total carbohydrate content in the 21-day biofilms, confocal microscopic analysis revealed that collagen and saliva conditioning selectively increased the polysaccharide content of 21-day biofilms, compared to the 3-day biofilms (P < 0.05).<br><br>CONCLUSIONS: The results of this study raise an important methodological concern that the substrate conditioning substances and biofilm age differentially influence the cellular and extracellular matrix components of E. faecalis biofilms.},
}
@article {pmid31407877,
year = {2019},
author = {Nie, L and Li, Y and Chen, S and Li, K and Huang, Y and Zhu, Y and Sun, Z and Zhang, J and He, Y and Cui, M and Wei, S and Qiu, F and Zhong, C and Liu, W},
title = {Biofilm Nanofiber-Coated Separators for Dendrite-Free Lithium Metal Anode and Ultrahigh-Rate Lithium Batteries.},
journal = {ACS applied materials &amp; interfaces},
volume = {11},
number = {35},
pages = {32373-32380},
doi = {10.1021/acsami.9b08656},
pmid = {31407877},
issn = {1944-8252},
abstract = {Rechargeable batteries that combine high energy density with high power density are highly demanded. However, the wide utilization of lithium metal anode is limited by the uncontrollable dendrite growth, and the conventional lithium-ion batteries (LIBs) commonly suffer from low rate capability. Here, we for the first time develop a biofilm-coated separator for high-energy and high-power batteries. It reveals that the coating of Escherichia coli protein nanofibers can improve electrolyte wettability and lithium transference number and enhance adhesion between separators and electrodes. Thus, lithium dendrite growth is impeded because of the uniform distribution of the Li-ion flux. The modified separator also enables the stable cycling of high-voltage Li|Li1.2Mn0.6Ni0.2O2 (LNMO) cells at an extremely high rate of 20 C, delivering a high specific capacity of 83.1 mA h g-1, which exceeds the conventional counterpart. In addition, the modified separator in the Li4Ti5O12|LNMO full cell also exhibits a larger capacity of 68.2 mA h g-1 at 10 C than the uncoated separator of 37.4 mA h g-1. Such remarkable performances of the modified separators arise from the conformal, adhesive, and endurable coating of biofilm nanofibers. Our work opens up a new opportunity for protein-based biomaterials in practical application of high-energy and high-power batteries.},
}
@article {pmid31407437,
year = {2019},
author = {Daubert, DM and Weinstein, BF},
title = {Biofilm as a risk factor in implant treatment.},
journal = {Periodontology 2000},
volume = {81},
number = {1},
pages = {29-40},
doi = {10.1111/prd.12280},
pmid = {31407437},
issn = {1600-0757},
abstract = {This article summarizes the microbiological findings at dental implants, drawing distinctions between the peri-implant microbiome and the periodontal microbiome, and summarizes what is known regarding biofilm as a risk factor for specific stages of implant treatment. Targeted microbial analysis is reviewed as well as the latest results from open-ended sequencing of the peri-implant flora. At this time there remains a lack of consensus for a specific microbial profile that is associated with peri-implantitis, suggesting that there may be other factors which influence the microbiome such as titanium surface dissolution. Therapeutic interventions to address the biofilm are presented at the preoperative, perioperative, and postoperative stages. Evidence supports that perioperative chlorhexidine reduces biofilm-related implant complications and failure. Regular maintenance for dental implants is also shown to reduce peri-implant mucositis and implant failure. Maintenance procedures should aim to disrupt the biofilm without damaging the titanium dioxide surface layer in an effort to prevent further oxidation. Evidence supports the use of glycine powder air polishing as a valuable adjunct to conventional therapies for use at implant maintenance visits. For the treatment of peri-implantitis, nonsurgical therapy has not been shown to be effective, and while surgical intervention is not always predictable, it has been shown to be superior to nonsurgical treatment for decontamination of the implant surface that is not covered by bone.},
}
@article {pmid31406097,
year = {2019},
author = {Saad, A and Nikaido, T and Abdou, A and Matin, K and Burrow, MF and Tagami, J},
title = {Inhibitory effect of zinc-containing desensitizer on bacterial biofilm formation and root dentin demineralization.},
journal = {Dental materials journal},
volume = {},
number = {},
pages = {},
doi = {10.4012/dmj.2018-352},
pmid = {31406097},
issn = {1881-1361},
abstract = {This study compared the effect of a novel zinc containing, Caredyne Shield (CS), and a fluoroaluminocalciumsilicate-based, Nanoseal (NS) desensitizers on dentin tubule occlusion, inhibition of Streptococcus mutans (S. mutans) biofilm growth, and resistance to bacterial demineralization. Desensitizers were applied to simulated hypersensitive bovine dentin, with distilled water used as a control. S. mutans biofilms were grown on the surface of each specimen in an oral biofilm simulator. CS showed the least bacterial count and water insoluble glucan amount followed by NS. Transverse micro radiography revealed that both CS and NS showed significant reduction in mineral loss and lesion depth of the associated lesion. Scanning electron micrographs showed that the two desensitizers formed obvious depositions on the dentin surfaces, occlusion of tubules and mineral tag formation.},
}
@article {pmid31405860,
year = {2019},
author = {Willems, HME and Stultz, JS and Coltrane, ME and Fortwendel, JP and Peters, BM},
title = {Disparate Candida albicans biofilm formation in clinical lipid emulsions due to capric acid mediated inhibition.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01394-19},
pmid = {31405860},
issn = {1098-6596},
abstract = {Receipt of parenteral nutrition (PN) remains an independent risk factor for developing catheter-related blood stream infections (CR-BSI) caused by fungi, including the polymorphic fungus Candida albicans that is notoriously adept at forming drug-resistant biofilm structures. Among a variety of macronutrients, PN solutions contain lipid emulsions to supply daily essential fats and are often delivered via central venous catheters (CVC). Therefore, using an in vitro biofilm model system, we sought to determine whether various clinical lipid emulsions differentially impacted biofilm growth in C. albicans We observed that lipid emulsions Intralipid® and Omegaven® both stimulated C. albicans biofilm formation during growth in minimal medium or a macronutrient PN solution. Conversely, Smoflipid® inhibited C. albicans biofilm formation by approximately 50%. Follow up studies revealed that while Smoflipid did not impair C. albicans growth, it did significantly inhibit hypha formation and hyphal elongation. Moreover, growth inhibition could be recapitulated in Intralipid® when supplemented with capric acid-a fatty acid present in Smoflipid® but absent in Intralipid®. Capric acid was also found to dose-dependently inhibit C. albicans biofilm formation in PN solutions. This is the first study to directly compare different clinical lipid emulsions for their capacity to affect C. albicans biofilm growth. Results derived from this study necessitate further research regarding different lipid emulsions and rates of fungal-associated CR-BSIs.},
}
@article {pmid31405233,
year = {2019},
author = {Kwiecińska-Piróg, J and Skowron, K and Bogiel, T and Białucha, A and Przekwas, J and Gospodarek-Komkowska, E},
title = {Vitamin C in the Presence of Sub-Inhibitory Concentration of Aminoglycosides and Fluoroquinolones Alters Proteus mirabilis Biofilm Inhibitory Rate.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {3},
pages = {},
doi = {10.3390/antibiotics8030116},
pmid = {31405233},
issn = {2079-6382},
abstract = {Vitamin C has antimicrobial activity and is often used as an oral supplement accompanying antibiotic treatment in urinary tract infections (UTI). Proteus mirabilis is the third common species responsible for UTIs that are mostly treated with fluoroquinolones or aminoglycosides. Treatment of the UTI caused by P. mirabilis is problematic due to the ability to form biofilm on the urinary catheters. The aim of the study was to evaluate the influence of ascorbic acid in combination with antibiotics on P. mirabilis abilities to form biofilm. The susceptibility of P. mirabilis reference strain ATCC® 29906™ and four clinical strains isolated from the urine samples of patients with urinary catheter were evaluated according to EUCAST recommendations. The influence of ascorbic acid (0.4 mg × mL-1) in combination with antibiotics on biofilm formation was evaluated spectrophotometrically. Aminoglycosides at sub-inhibitory concentrations more successfully limited biofilm formation by P. mirabilis strains without ascorbic acid addition. Inhibition rate differences at the lowest concentrations of gentamicin and amikacin were statistically significant (p ≤ 0.05). Ascorbic acid addition to the culture medium limited the inhibitory effect of fluoroquinolones, facilitating biofilm formation by P. mirabilis strains. The addition of ascorbic acid during aminoglycosides therapy may disturb treatment of urinary tract infections related to the presence of P. mirabilis biofilm.},
}
@article {pmid31405172,
year = {2019},
author = {Guzzon, A and Di Pippo, F and Congestri, R},
title = {Wastewater Biofilm Photosynthesis in Photobioreactors.},
journal = {Microorganisms},
volume = {7},
number = {8},
pages = {},
doi = {10.3390/microorganisms7080252},
pmid = {31405172},
issn = {2076-2607},
support = {QLK3-CT2002-01938//EC/ ; },
abstract = {Photosynthetic performance of algal-bacterial biofilms from an Italian wastewater treatment plant was studied in a flow-lane photobioreactor at different irradiances, temperatures, and flow regime to evaluate the effects of these environmental parameters on biofilms' functioning, in view of application of these communities in wastewater biological treatment. Pulse amplitude modulated fluorescence was used to estimate the effective quantum yield of PSII (ΔF/Fm') of the light-acclimated biofilms and to perform rapid light curves (RLCs) for the determination of the photosynthetic parameters (rel.ETRmax, α, Ik). Chl a, ash free dry weight (AFDW), and dry weight (DW) were measured to assess phototrophic and whole biofilm biomass development over time. From the analysis of photosynthetic parameter variation with light intensity, temperature and flow rate, it was possible to identify the set of experimental values favoring biofilm photosynthetic activity. Biomass increased over time, especially at the highest irradiances, where substrata were fastly colonized and mature biofilms developed at all temperatures and flow conditions tested.},
}
@article {pmid31404843,
year = {2019},
author = {Kłodzińska, SN and Wan, F and Jumaa, H and Sternberg, C and Rades, T and Nielsen, HM},
title = {Utilizing nanoparticles for improving anti-biofilm effects of azithromycin: A head-to-head comparison of modified hyaluronic acid nanogels and coated poly (lactic-co-glycolic acid) nanoparticles.},
journal = {Journal of colloid and interface science},
volume = {555},
number = {},
pages = {595-606},
doi = {10.1016/j.jcis.2019.08.006},
pmid = {31404843},
issn = {1095-7103},
abstract = {HYPOTHESIS: The widespread resistance of bacteria to traditional antibiotic treatments has expedited the search for novel therapies against these pathogens. The hypothesis of this work is that two distinctively different polymeric delivery systems, specifically D-α-tocopherol polyethylene glycol 1000 succinate (TPGS)-poly(lactic-co-glycolic acid) (PLGA) nanoparticles and octenyl succinic anhydride-modified low molecular weight hyaluronic acid (OSA-HA) nanogels may be used to substantially improve the properties of azithromycin, allowing its use for effective treatment of Pseudomonas aeruginosa biofilm infections.<br><br>EXPERIMENTS: Azithromycin was encapsulated in both delivery systems and the physicochemical properties of the loaded delivery systems, including size, surface charge and drug loading were evaluated. Additionally, particle interaction with a mucin layer, penetration into a bacterial biofilm, prevention of biofilm formation and eradication of pre-formed biofilms, the influence on production of virulence factors and bacterial motility as well as cytotoxicity towards hepatocytes and lung epithelial cells were compared head-to-head.<br><br>FINDINGS: The TPGS-PLGA nanoparticles noticeably improved the antimicrobial activity and the biofilm prevention activity of azithromycin whereas the OSA-HA nanogels showed reduced mucin interactions together with improved reduction of pre-formed biofilms and maintained the low eukaryotic cell cytotoxicity of azithromycin.},
}
@article {pmid31404739,
year = {2019},
author = {Sun, G and Wan, J and Sun, Y and Li, H and Chang, C and Wang, Y},
title = {Enhanced removal of nitrate and refractory organic pollutants from bio-treated coking wastewater using corncobs as carbon sources and biofilm carriers.},
journal = {Chemosphere},
volume = {237},
number = {},
pages = {124520},
doi = {10.1016/j.chemosphere.2019.124520},
pmid = {31404739},
issn = {1879-1298},
abstract = {The quality of the bio-treated coking wastewater (BTCW) is difficult to meet increasingly stringent coking wastewater discharge standards and future wastewater recycling needs. In this study, the pre-treatment process of BTCW was installed including the two up-flow fixed-bed bioreactors (UFBRs) which were separately filled with alkali-pretreated or no alkali-pretreated corncobs used as solid carbon sources as well as biofilm carriers. Results showed that this pre-treatment process could significantly improve the biodegradability of BTCW and increase the C/N ratio. Thus, over 90% of residual nitrate in BTCW were removed stably. Furthermore, GC-MS analysis confirmed that the typical refractory organic matters decreased significantly after UFBRs pre-treatment. High-throughput sequencing analysis using 16S rRNA demonstrated that dominant denitrifiers, fermentative bacteria and refractory-organic-pollutants-degrading bacteria co-existed inside the UFBRs system. Compared with no alkali-pretreated corncobs, alkali-pretreated corncobs provided more porous structure and much stable release of carbon to guarantee the growth and the quantity of the functional bacteria such as denitrifiers. This study indicated that the UFBRs filled with alkali-pretreated corncobs could be utilized as an effective alternative for the enhanced treatment of the BTCW.},
}
@article {pmid31404326,
year = {2019},
author = {Wang, S and Wang, Y and Wang, Y and Duan, Z and Ling, Z and Wu, W and Tong, S and Wang, H and Deng, S},
title = {Theaflavin-3,3'-Digallate Suppresses Biofilm Formation, Acid Production, and Acid Tolerance in Streptococcus mutans by Targeting Virulence Factors.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1705},
doi = {10.3389/fmicb.2019.01705},
pmid = {31404326},
issn = {1664-302X},
abstract = {As one of the most important cariogenic pathogens, Streptococcus mutans has strong abilities to form biofilms, produce acid and tolerate acid. In present study, we found that theaflavin-3,3'-digallate (TF3) had an inhibitory effect on S. mutans UA159 in vitro. Visualized by field emission-scanning electron microscopy, the suppressed formation of S. mutans biofilms grown with TF3 at sub-inhibitory concentrations could be attributed to the reduced biofilm matrix, which was proven to contain glucans and extracellular DNA (eDNA). Glucan-reduced effect of TF3 was achieved by down-regulating expression levels of gtfB, gtfC, and gtfD encoding glucosyltransferases. Besides, TF3 reduced eDNA formation of S. mutans by negatively regulating lrgA, lrgB, and srtA, which govern cell autolysis and membrane vesicle components. Furthermore, TF3 also played vital roles in antagonizing preformed biofilms of S. mutans. Bactericidal effects of TF3 became significant when its concentrations increased more than twofold of minimum inhibitory concentration (MIC). Moreover, the capacities of S. mutans biofilms to produce acid and tolerate acid were significantly weakened by TF3 at MIC. Based on real-time PCR (RT-PCR) analysis, the mechanistic effects of TF3 were speculated to comprise the inhibition of enolase, lactate dehydrogenase, F-type ATPase and the agmatine deiminase system. Moreover, TF3 has been found to downregulate LytST, VicRK, and ComDE two component systems in S. mutans, which play critical roles in the regulatory network of virulence factors. Our present study found that TF3 could suppress the formation and cariogenic capacities of S. mutans biofilms, which will provide new strategies for anti-caries in the future.},
}
@article {pmid31403663,
year = {2019},
author = {Shafeeq, S and Pannanusorn, S and Elsharabasy, Y and Ramírez-Zavala, B and Morschhäuser, J and Römling, U},
title = {Impact of manganese on biofilm formation and cell morphology of Candida parapsilosis clinical isolates with different biofilm forming abilities.},
journal = {FEMS yeast research},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsyr/foz057},
pmid = {31403663},
issn = {1567-1364},
abstract = {The commensal species Candida parapsilosis is an emerging human pathogen that has the ability to form biofilms. In this study, we explored the impact of the divalent cations cobalt (Co2+), copper (Cu2+), iron (Fe3+), manganese (Mn2+), nickel (Ni2+) and zinc (Zn2+) on biofilm formation of clinical isolates of C. parapsilosis with no, low and high biofilm-forming abilities at 30 and 37°C. All strains beside one isolate showed a concentration dependent enhancement of biofilm formation at 30°C in the presence of Mn2+ with a maximum at 2 mM. The biofilm forming ability of no- and low-biofilm forming isolates was more than two-fold enhanced in the presence of 2 mM Mn2+, while the effect in high biofilm forming isolate was significantly less pronounced. Of note, cells in the biofilms of no- and low-biofilm forming strains differentiated into yeast and pseudohyphal cells similar in morphology to high biofilm formers. The biofilm transcriptional activator BCR1 has a dual developmental role in the absence and presence of 2 mM Mn2+ as it promoted biofilm formation of no biofilm forming strains, and, surprisingly, suppressed cells of no biofilm forming strains to develop into pseudohyphae and/or hyphae. Thus, environmental conditions can significantly affect the amount of biofilm formation and cell morphology of C. parapsilosis with Mn2+ to overcome developmental blocks to trigger biofilm formation and to partially relieve BCR1 suppressed cell differentiation.},
}
@article {pmid31402901,
year = {2019},
author = {van Vugt, TAG and Arts, JJ and Geurts, JAP},
title = {Antibiotic-Loaded Polymethylmethacrylate Beads and Spacers in Treatment of Orthopedic Infections and the Role of Biofilm Formation.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1626},
doi = {10.3389/fmicb.2019.01626},
pmid = {31402901},
issn = {1664-302X},
abstract = {Polymethylmethacrylate (PMMA) also referred as (acrylic) bone cement is a non-degradable biomaterial that has been used in clinical orthopedic practice for several decades. PMMA can be used in a plain formulation, but is often used in an antibiotic-loaded formulation in (primary and revision) arthroplasty and in treatment of orthopedic infections as prosthetic joint infections (PJI) and chronic osteomyelitis. In treatment of PJIs antibiotic-loaded PMMA is often used as a carrier material for local antibiotic delivery in addition to treatment with systemic antibiotics. In this case, the antibiotic-loaded PMMA is often used as a spacer or as a bead chain. Since the introduction of PMMA as an antibiotic carrier there is a tremendous amount of scientific and clinical papers published, which studied numerous different aspects of antibiotic-loaded PMMA. This paper will review the research regarding basic principles of antibiotic-loaded PMMA as mechanism of action, antibiotic-release capacities, choice of antibiotics and influences on mechanical properties of PMMA. Subsequently, concerns regarding the application of antibiotic-loaded PMMA, biofilm formation, antibiotic resistance and local or systemic toxicity will be discussed. In addition to these subjects, the role of antibiotic loaded PMMA in clinical treatment of PJIs and chronic osteomyelitis is discussed in the final part of this paper.},
}
@article {pmid31402749,
year = {2019},
author = {Krantz, GP and Lucas, K and Wunderlich, EL and Hoang, LT and Avci, R and Siuzdak, G and Fields, MW},
title = {Bulk phase resource ratio alters carbon steel corrosion rates and endogenously produced extracellular electron transfer mediators in a sulfate-reducing biofilm.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-15},
doi = {10.1080/08927014.2019.1646731},
pmid = {31402749},
issn = {1029-2454},
abstract = {Desulfovibrio alaskensis G20 biofilms were cultivated on 316 steel, 1018 steel, or borosilicate glass under steady-state conditions in electron-acceptor limiting (EAL) and electron-donor limiting (EDL) conditions with lactate and sulfate in a defined medium. Increased corrosion was observed on 1018 steel under EDL conditions compared to 316 steel, and biofilms on 1018 carbon steel under the EDL condition had at least twofold higher corrosion rates compared to the EAL condition. Protecting the 1018 metal coupon from biofilm colonization significantly reduced corrosion, suggesting that the corrosion mechanism was enhanced through attachment between the material and the biofilm. Metabolomic mass spectrometry analyses demonstrated an increase in a flavin-like molecule under the 1018 EDL condition and sulfonates under the 1018 EAL condition. These data indicate the importance of S-cycling under the EAL condition, and that the EDL is associated with increased biocorrosion via indirect extracellular electron transfer mediated by endogenously produced flavin-like molecules.},
}
@article {pmid31402466,
year = {2019},
author = {Balasundararajan, V and Dananjeyan, B},
title = {Occurrence of diversified N-acyl homoserine lactone mediated biofilm-forming bacteria in rice rhizoplane.},
journal = {Journal of basic microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1002/jobm.201900202},
pmid = {31402466},
issn = {1521-4028},
support = {5-5/2014 - TS VII//Ministry of Human Resource Development, New Delhi, India/ ; },
abstract = {Quorum sensing (QS)-mediated biofilm-forming rhizobacteria are indispensable due to their competitiveness in the crop rhizosphere. In the present work, we have reported on the occurrence of diversified bacterial species capable of producing N-acyl homoserine lactone (AHL) as the QS signal in the roots of a rice plant grown under field conditions. The AHL-producing bacteria were directly isolated from the rice root by the biosensor reporter (Chromobacterium violaceum CV026) overlay method and characterized for biofilm production by the microtiter plate method. A total of 48 QS-positive bacterial isolates were purified from different aged (7, 20, 24, 26, and 36 days) rice seedlings. The in vitro biofilm production and genetic diversity as revealed by BOX-PCR fingerprinting showed high variability among the isolates. Most of the best biofilm-forming isolates produced a N-butyryl dl-homoserine lactone (a C4-AHL type) signal in the medium. The 16S ribosomal RNA (rRNA) gene sequence of these putative elite isolates identified that they were close to Aeromonas hydrophila (QS7-4; QS36-2), A. enteropelongenes (QS20-8), A. veronii (QS36-3), Enterobacter sp. (QS20-11), Klebsiella pneumoniae (QS24-6), Kosakonia cowanii (QS24-21), Providentia rettigeri (QS24-2), Sphingomonas aquatilis (QS24-17), and Pseudomonas sihuiensis (QS24-20). These strains profusely colonized the rice root upon inoculation and formed biofilms on the surface of the root under gnotobiotic conditions. Developing inoculants from these strains would ensure competitive colonization on the rhizoplane of the crop through their biofilm and thereby improve plant growth and health.},
}
@article {pmid31401655,
year = {2019},
author = {Bajoul Kakahi, F and Ly, S and Tarayre, C and Deschaume, O and Bartic, C and Wagner, P and Compère, P and Derdelinckx, G and Blecker, C and Delvigne, F},
title = {Modulation of fungal biofilm physiology and secondary product formation based on physico-chemical surface properties.},
journal = {Bioprocess and biosystems engineering},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00449-019-02187-6},
pmid = {31401655},
issn = {1615-7605},
abstract = {Relative to the amount of knowledge concerning bacterial biofilms, little is known about the impact of physico-chemical properties of support material on fungal biofilm adhesion and physiology. In the field of industrial fermentation, large-scale production of low-cost fungal secondary product is a challenging area of research. In the present work, the effect of physico-chemical surface properties of five different materials (Teflon, glass, Viton™ rubber, silicon rubber, and stainless steel) on the production of class II hydrophobins (HFBI and HFBII) from Trichoderma reesei (HFB2a-2) and Trichoderma harzianum) was evaluated. Two culture systems (shake flask and drip flow reactor (DFR)) were used in this study to promote biomass growth and the production of hydrophobins. Furthermore, the effect of physico-chemical surface properties (hydrophobicity, surface energy) and surface texture (roughness) of support material on the initial colonization and attachment of the fungal biofilm was evaluated. Maximum biofilm productivity was obtained using Viton™ rubber for T. reesei and Viton™ rubber and stainless steel as support materials for T. harzianum. Scanning electron microscope (SEM) revealed that fungal biofilm adhesion was higher on the rough hydrophobic Viton rubber surface as compared to the smooth hydrophobic Teflon surface. Initial colonization initiated because of surface irregularities and holes in the material as hyphal filaments. Moreover, compared to traditional submerged fermentation, a significant increase in biofilm productivity for both strains (T. reesei, T. harzianum) in all five materials was obtained.},
}
@article {pmid31401462,
year = {2019},
author = {Czuban, M and Wulsten, D and Wang, L and Di Luca, M and Trampuz, A},
title = {Release of different amphotericin B formulations from PMMA bone cements and their activity against Candida biofilm.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {183},
number = {},
pages = {110406},
doi = {10.1016/j.colsurfb.2019.110406},
pmid = {31401462},
issn = {1873-4367},
abstract = {Amphotericin B is used for local delivery from polymethylmethacrylate to treat fungal prosthetic joint infections. The optimal amphotericin B formulation and the influence of different poragens in the bone cements are unknown. To investigate the necessary amount of amphotericin B in the bone cement to prevent Candida biofilm several amphotericin B formulations were studied: non-liposomal and liposomal with or without poragen gentamicin. For the non-liposomal formulation, standard bile salt, the sodium deoxycholate, was used and additionally N-methyl-D-glucamine/palmitate was applied. The activity of the released amphotericin B was tested against C. albicans, C. glabrata, C. parapsilosis and C. krusei biofilms with application of the isothermal calorimeter and standard microbiological methods. Compressive strength was measured before and after antifungal elution from the cements. There is less aggregated N-methyl-D-glucamine/palmitate amphotericin B released but its antifungal activity is equivalent with the deoxycholate amphotericin B. The minimum quantity of antifungal preventing the Candida biofilm formation is 12.5 mg in gram of polymer powder for both non-liposomal formulations. The addition of gentamicin reduced the release of sodium deoxycholate amphotericin B. Gentamicin can be added to N-methyl-D-glucamine/palmitate amphotericin B in order to boost the antifungal release. When using liposomal amphotericin B more drug is released. All amphotericin B formulations were active against Candida biofilms. Although compressive strength slightly decreased, the obtained values were above the level of strength recommended for the implant fixation. The finding of this work might be beneficial for the treatment of the prosthetic joint infections caused by Candida spp.},
}
@article {pmid31400984,
year = {2019},
author = {Ionescu, A and Brambilla, E and Hahnel, S},
title = {Does recharging dental restorative materials with fluoride influence biofilm formation?.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.dental.2019.07.019},
pmid = {31400984},
issn = {1879-0097},
abstract = {OBJECTIVES: To investigate the influence of recharging dental restorative materials with fluoride on biofilm formation.<br><br>METHODS: Specimens produced from a high-viscosity glass ionomer cement (HVGIC), a resin-modified glass ionomer cement (RMGIC), and a resin-based composite (RBC) were randomly allotted to incubation in artificial saliva either for one week (AS-1), for five weeks (AS-5), for five weeks including twice/day brushing with 1450ppm NaF toothpaste (AS-5-brush), or one-time exposition to 5000ppm NaF after five weeks of incubation (AS-5-exp). Human enamel was used as reference. Surface roughness and the release of fluoride from the specimens was determined; biofilm formation was simulated using mono- or multispecies microbiological models and analysed employing an MTT-based approach and confocal laser-scanning microscopy.<br><br>RESULTS: Monospecies biofilm formation was significantly reduced on HVGIC in comparison to RMGIC and RBC. It was also reduced on HVGIC and enamel after treatment with fluoride in groups AS-5-brush and AS-5-exp in comparison to AS-5. These effects were particularly pronounced after 24h, and less pronounced after 48h of biofilm formation. In the multispecies microbiological model, similar observations were identified for HVGIC, while for enamel a significant reduction in biofilm formation was observed in groups AS-5-brush and AS-5-exp. No significant effect of fluoride treatments was identified for RMGIC and RBC, regardless of the microbiological model applied.<br><br>SIGNIFICANCE: These data indicate that biofilm formation on the surfaces of a glass ionomer cement and enamel can be relevantly influenced by treatment with fluoride. Enamel may serve as a fluoride reservoir which requires regular recharge.},
}
@article {pmid31400892,
year = {2019},
author = {Vasileiou, NGC and Chatzopoulos, DC and Cripps, PJ and Ioannidi, KS and Gougoulis, DA and Chouzouris, TM and Lianou, DT and Gonzalez-Valerio, TC and Vallverdu, RG and Argyros, S and Cesio, M and Font, I and Mavrogianni, VS and Petinaki, E and Fthenakis, GC},
title = {Evaluation of efficacy of a biofilm-embedded bacteria-based vaccine against staphylococcal mastitis in sheep-A randomized, placebo-controlled field study.},
journal = {Journal of dairy science},
volume = {},
number = {},
pages = {},
doi = {10.3168/jds.2019-16287},
pmid = {31400892},
issn = {1525-3198},
abstract = {Our objective was to evaluate the efficacy of a vaccine against staphylococcal mastitis in 5 dairy sheep farms, with 316 ewes in the vaccinated (V) group and 307 in the control (C) group studied throughout a lactation period. Two administrations of the vaccine were performed during the last stage of gestation of ewes. Starting 15 d after lambing and at monthly intervals thereafter, up to 9 milk samplings were performed for bacteriological and cytological examinations. Staphylococcal isolates recovered were examined for biofilm formation. Blood samples were collected for measurement of IgG poly-N-acetylglucosamine-specific antibodies. The most frequently isolated bacteria were staphylococci: 56.4 and 76.1%, respectively, of total isolates recovered from ewes of group V and C, respectively; staphylococci as causal agents of mastitis were isolated less frequently from V (5.3%) than in ewes in C (10.3%). Among mastitis-associated staphylococcal isolates recovered from V ewes, a smaller proportion was biofilm-forming than among ones from C: 53.2% versus 74.9% of isolates; biofilm-forming staphylococci as causal agents of mastitis were isolated less frequently from ewes in group V (2.3%) than in ewes in group C (6.0%). Anti-poly-N-acetylglucosamine-specific antibody values increased in V ewes and were higher than in C; a greater proportion of ewes with low antibody titers developed staphylococcal mastitis (41.4%) than of V ewes with high antibody titers (17.0%). Incidence risk of mastitis, staphylococcal mastitis, and biofilm-associated staphylococcal mastitis was smaller in V than in C: 36.7, 17.1, and 8.0% versus 44.3, 30.9, and 18.9%, respectively. The first case of staphylococcal mastitis occurred later in V than in C: 3rd versus 2nd sampling point. Overall, efficacy of the vaccine was 44.6% for staphylococcal mastitis, 57.7% for biofilm-associated staphylococcal mastitis, 33.1% for staphylococcal intramammary infection, and 51.5% for biofilm-associated staphylococcal intramammary infection. Nevertheless, vaccination should not be the only means for controlling mastitis; other udder health management measures should be included therein to improve control of the infection.},
}
@article {pmid31400863,
year = {2019},
author = {Hans, S and Fatima, Z and Hameed, S},
title = {Retrograde signaling disruption influences ABC superfamily transporter, ergosterol and chitin levels along with biofilm formation in Candida albicans.},
journal = {Journal de mycologie medicale},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.mycmed.2019.07.003},
pmid = {31400863},
issn = {1773-0449},
abstract = {OBJECTIVE: The rise in fungal infections is alarming due to emergence of multidrug drug resistance (MDR). Hence elucidating novel drug targets to circumvent the problem of MDR warrants immediate attention. This study analyzes the effect of retrograde (RTG) signaling disruption on major MDR mechanisms and virulence of the human pathogenic fungal species Candida albicans.<br><br>MATERIAL AND METHODS: Drug transporter activity was measured by rhodamine 6G (R6G) efflux. Membrane damage was studied by propidium iodide intake and ergosterol level determination. Cell wall effect was estimated by quantifying chitin levels and cell sedimentation rate. Biofilm formation was visualized by calcoflour white and crystal violet staining and measured by dry mass and MTT assay. Cell adherence to buccal epithelial cell was determined by trypan blue staining and MTT assay. Virulence was studied using nematode model Caenorhabditis elegans.<br><br>RESULT: We demonstrated that mutant of transcription factor CaRTG3 leads to impaired efflux activity of ATP Binding Cassette (ABC) superfamily multidrug transporters. We further uncover that rtg3 mutant exhibited a disrupted membrane, decreased ergosterol levels and increased chitin content. Furthermore, RTG signaling disruption leads to inhibited biofilm formation and cell adherence to buccal epithelial cells. Lastly, rtg3 mutant displayed a reduced infectivity in C. elegans illustrating its vulnerability as antifungal target. Interestingly, all the abrogated phenotypes could be rescued in the revertant strain of rtg3 mutant.<br><br>CONCLUSION: Present study establishes a link between RTG signaling, drug efflux and biofilm formation and validates CaRTG3 as antifungal target. Intricate studies are needed to further understand and exploit this therapeutic opportunity.},
}
@article {pmid31400688,
year = {2019},
author = {Li, H and Zhou, L and Lin, H and Zhang, W and Xia, S},
title = {Nitrate effects on perchlorate reduction in a H2/CO2-based biofilm.},
journal = {The Science of the total environment},
volume = {694},
number = {},
pages = {133564},
doi = {10.1016/j.scitotenv.2019.07.370},
pmid = {31400688},
issn = {1879-1026},
abstract = {The H2/CO2-based membrane biofilm reactor (H2/CO2-MBfR) that effectively combines microporous diffusions of H2 and CO2 is efficient in removing perchlorate (ClO4-). Nitrate (NO3-) is a common oxidized contaminant frequently coexists with ClO4- in water, with the NO3- concentration in most ClO4--contaminated waters being several orders of magnitude higher than ClO4-. Determining the effect of NO3- on ClO4- reduction is a critical issue in practice. The ClO4- reduction performance, biofilm microbial community and influencing mechanism were investigated under a series of feed NO3- loadings in this work. ClO4- reduction was slightly promoted when NO3--N levels were <10 mg/L and inhibited at higher NO3--N levels. Denitrification competed more strongly for H2 than ClO4- reduction, regardless of H2 availability. A higher NO3--N loading was a strong driving force to change the biofilm microbial community. Betaproteobacteria were the dominant bacteria at all stages, and the biofilm reactor was enriched in Methyloversatilis and Zoogloea (31.9-56.5% and 10.6-25.8%, respectively). Changes in the relative amounts of Methyloversatilis and Zoogloea coincided with changes in the ClO4- fluxes and removal efficiencies and the relative abundances of nitrogen cycle functional genes. These results suggest that Methyloversatilis and Zoogloea likely follow independent reduction mechanisms for ClO4- removal.},
}
@article {pmid31398534,
year = {2019},
author = {Dieser, SA and Fessia, AS and Zanotti, AR and Raspanti, CG and Odierno, LM},
title = {Fibronectin and laminin induce biofilm formation by Streptococcus uberis and decrease its penicillin susceptibility.},
journal = {Microbial pathogenesis},
volume = {136},
number = {},
pages = {103652},
doi = {10.1016/j.micpath.2019.103652},
pmid = {31398534},
issn = {1096-1208},
abstract = {The aim of this study was to determine the effect of fibronectin and laminin on the in vitro biofilm formation by Streptococcus uberis and the susceptibility to penicillin under planktonic and biofilm growth conditions. We observed that a high percentage (76.5%) of the S. uberis isolates was weak biofilm producers in Todd Hewitt Broth (THB). A high percentage of moderate (38.2%) or strong (53%) biofilm producers was observed in THB supplemented with laminin or fibronectin, respectively. All S. uberis isolates growing as planktonic cells were sensitive to penicillin. Minimum biofilm inhibitory concentrations (MBICs) were ranging between 0.25 and 2 μg/ml, whereas minimum biofilm eradication concentrations (MBECs) ranging from 8 to 256 μg/ml. These results show that biofilm-growing S. uberis cells required higher concentrations of the antibiotic than those needed to inhibit planktonic cells. Similar MBICs of penicillin were obtained when S. uberis cells growing in THB supplemented or not with laminin or fibronectin, whereas the MBECs markedly increased when one of two proteins were added to culture medium compared with the medium without proteins. To the best of our knowledge, this is the first report of decreased susceptibility to penicillin likely related to a higher production of biofilms stimulated by laminin or fibronectin. Therapeutic failures of penicillin to treat S. uberis infections may be due to biofilm formation.},
}
@article {pmid31398514,
year = {2019},
author = {Shin, NR and Yi, YJ and Choi, JS},
title = {Hand motor functions on the presence of red fluorescent dental biofilm in older community-dwelling Koreans.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.08.010},
pmid = {31398514},
issn = {1873-1597},
abstract = {BACKGROUND: The Quantitative Light-induced Fluorescence-Digital (QLF-D) system visualizes old and mature dental biofilm as red fluorescence. Risk factors for poor oral hygiene have been identified, however, few studies have evaluated the relationship between mature dental biofilm and hand motor functions. This study aimed to investigate the effects of two important manual motor functions for object manipulation -handgrip strength and manual dexterity- on the presence of red fluorescent dental biofilm in older community-dwelling Koreans using QLF-D, an optical device that reveals dental biofilm.<br><br>METHODS: This cross-sectional study included 70 Korean participants aged ≥65 years, all of whom completed questionnaires and were tested for handgrip strength and manual dexterity. In total, 840 dental surfaces were photographed using QLF-D, and ΔR20 values, which reflect mature dental biofilm accumulation, were calculated. The t-test was performed to analyze the differences in the △R20 values according to sociodemographic characteristics, health-related characteristics and hand motor functions, while multiple linear regression analysis was used to investigate the effects of hand motor functions on the △R20 values.<br><br>RESULTS: Multivariate regression analysis revealed that handgrip strength (β = -0.294) was the factor most strongly affecting mature dental biofilm accumulation (ΔR20), followed by tooth-brushing time (β = -0.262) and manual dexterity (β = -0.241).<br><br>CONCLUSIONS: Reductions in handgrip strength and manual dexterity were independent risk factors for pathogenic dental biofilm accumulation. The results of this investigation suggest that programs designed to prevent the decline, as well as improve, handgrip strength and manual dexterity might improve the oral hygiene of older adults.},
}
@article {pmid31398473,
year = {2019},
author = {Arenas-Vivo, A and Amariei, G and Aguado, S and Rosal, R and Horcajada, P},
title = {An Ag-loaded photoactive nano-metal organic framework as a promising biofilm treatment.},
journal = {Acta biomaterialia},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.actbio.2019.08.011},
pmid = {31398473},
issn = {1878-7568},
abstract = {Surface biofilm inhibition is still currently a considerable challenge. Among other organisms, Staphylococcus aureus is notable for its ability to form a strong biofilm with proved resistance to chemotherapy. Contamination of high-touch surfaces with S. aureus biofilm not only promotes disease spread but also generates tremendous health-associated costs. Therefore, development of new bactericidal and antiadhesive surface coatings is a priority. Considering that metal-organic frameworks (MOFs) have recently emerged as promising antibacterial agents, we originally report here the synthesis of a multi-active silver-containing nanoscaled MOF composite as a potential surface coating against S. aureus biofilm owing to a triple effect: intrinsic bactericide activity of the MOF, biocidal character of silver nanoparticles (AgNPs), and photoactivity after UVA irradiation. AgNPs were successfully entrapped within the benchmarked nanoscaled porous photoactive titanium(IV) aminoterephthalate MIL-125(Ti)NH2 using a simple and efficient impregnation-reduction method. After complete characterization of the composite thin film, its antibacterial and anti-adherent properties were fully evaluated. After UVA irradiation, the composite coating exhibited relevant bacterial inhibition and detachment, improved ligand-to-cluster charge transfer, and steady controlled delivery of Ag+. These promising results establish the potential of this composite as an active coating for biofilm treatment on high-touch surfaces (e.g., surgical devices, door knobs, and rail bars). STATEMENT OF SIGNIFICANCE: Surface contamination due to bacterial biofilm formation is still a demanding issue, as it causes severe disease spread. One possible solution is the development of antifouling and antibacterial surface coatings. In this work, we originally propose the use of photoactive metal-organic frameworks (MOFs) for biofilm treatment. The novelty of this work relies on the following: i) the treatment of strongly contaminated surfaces, as previous studies with MOFs have exclusively addressed biofilm prevention; ii) this pioneering work reports both antiadherent effect, which removes the biofilm, and bacterial inhibition; iii) our original successful strategy has never been proposed thus far, involving the multi-active combination of 1) intrinsic antibacterial effect of a photoactive titanium-based nanoMOF, 2) immobilization of biocide silver nanoparticles, and 3) improved anti-bioadherent effect upon irradiation of the composite coating.},
}
@article {pmid31398188,
year = {2019},
author = {Rai, LS and Singha, R and Sanchez, H and Chakraborty, T and Chand, B and Bachellier-Bassi, S and Chowdhury, S and d'Enfert, C and Andes, DR and Sanyal, K},
title = {The Candida albicans biofilm gene circuit modulated at the chromatin level by a recent molecular histone innovation.},
journal = {PLoS biology},
volume = {17},
number = {8},
pages = {e3000422},
doi = {10.1371/journal.pbio.3000422},
pmid = {31398188},
issn = {1545-7885},
abstract = {Histone H3 and its variants regulate gene expression but the latter are absent in most ascomycetous fungi. Here, we report the identification of a variant histone H3, which we have designated H3VCTG because of its exclusive presence in the CTG clade of ascomycetes, including Candida albicans, a human pathogen. C. albicans grows both as single yeast cells and hyphal filaments in the planktonic mode of growth. It also forms a three-dimensional biofilm structure in the host as well as on human catheter materials under suitable conditions. H3VCTG null (hht1/hht1) cells of C. albicans are viable but produce more robust biofilms than wild-type cells in both in vitro and in vivo conditions. Indeed, a comparative transcriptome analysis of planktonic and biofilm cells reveals that the biofilm circuitry is significantly altered in H3VCTG null cells. H3VCTG binds more efficiently to the promoters of many biofilm-related genes in the planktonic cells than during biofilm growth, whereas the binding of the core canonical histone H3 on the corresponding promoters largely remains unchanged. Furthermore, biofilm defects associated with master regulators, namely, biofilm and cell wall regulator 1 (Bcr1), transposon enhancement control 1 (Tec1), and non-dityrosine 80 (Ndt80), are significantly rescued in cells lacking H3VCTG. The occupancy of the transcription factor Bcr1 at its cognate promoter binding sites was found to be enhanced in the absence of H3VCTG in the planktonic form of growth resulting in enhanced transcription of biofilm-specific genes. Further, we demonstrate that co-occurrence of valine and serine at the 31st and 32nd positions in H3VCTG, respectively, is essential for its function. Taken together, we show that even in a unicellular organism, differential gene expression patterns are modulated by the relative occupancy of the specific histone H3 type at the chromatin level.},
}
@article {pmid31397415,
year = {2019},
author = {Sampaio, GG and Leódido, G and Gonçalves, LM and Benini Paschoal, MA},
title = {In vitro antimicrobial potential of infant mouthwashes against streptococcus mutans biofilm: A preliminary study.},
journal = {Indian journal of dental research : official publication of Indian Society for Dental Research},
volume = {30},
number = {3},
pages = {399-402},
doi = {10.4103/ijdr.IJDR_500_17},
pmid = {31397415},
issn = {1998-3603},
abstract = {Background: Children and teenagers accumulate dental plaque easily due to immature motor coordination present at this specific age. Thus, chemical solutions such as mouthwashes are used for biofilm control. The widespread use of mouthwash could potentially change the oral environment though there is no evidence of its effects on the biofilm.<br><br>Aim: The present study aimed to investigate the in vitro antimicrobial potential of infant mouthwashes on mature Streptococcus mutans biofilm.<br><br>Methods: The susceptibility of S. mutans biofilm UA 159 (ATCC700610) to infant mouthwashes was tested with childrens mouthwashes containing the following active agents: G1-cetylpyridinium chloride, G2-xylitol and triclosan and G3-Malva sylvestris and xylitol. Phosphage-buffered saline (PBS) was used at the negative control (G4). In this study, cariogenic biofilm was exposed once a day for one minute to the mouthwashes over a period of five days. Following this, an aliquot of each mouthwash used was seeded in brain heart infusion (BHI) agar and then incubated at 37°C, 5% CO2 for 48 h. The results were expressed as colony-forming units (CFU) and converted into log10. The results were submitted to ANOVA and Tukey's test at 5%.<br><br>Results: It was observed 7.75, 7.66, and 7.49 CFUlog10 values to G1, G2, and G3, respectively, with 9.53 CFUlog10 value to G4. Accordingly, all studied mouthwashes showed no significant statistical difference between them but with statistically significant bacterial reduction in comparison to control group.<br><br>Conclusion: Infant mouthwashes presented a highly significant antimicrobial effect on cariogenic biofilm in an in vitro model, which raises concern when used by a young population.},
}
@article {pmid31397177,
year = {2019},
author = {Acquaviva, R and D'Angeli, F and Malfa, GA and Ronsisvalle, S and Garozzo, A and Stivala, A and Ragusa, S and Nicolosi, D and Salmeri, M and Genovese, C},
title = {Antibacterial and anti-biofilm activities of walnut pellicle extract (Juglans regia L.) against coagulase-negative staphylococci.},
journal = {Natural product research},
volume = {},
number = {},
pages = {1-6},
doi = {10.1080/14786419.2019.1650352},
pmid = {31397177},
issn = {1478-6427},
abstract = {Juglans regia L. (common walnut) is a deciduous tree belonging to Juglandaceae family. Since ancient time, walnut was widely used in traditional medicine for its antioxidant, antidiabetic, antimicrobial, anti-inflammatory, anti-atherogenic and liver-protective effects. In this work, the antibacterial and anti-biofilm activities of walnuts pellicle extract against coagulase-negative staphylococci were evaluated. Qualitative chemical analysis was performed by the thin layer chromatography. UPLC-Ms/Ms was used to identify the chemical composition of J. regia extract. The total flavonoid and phenolic contents were determined by the Aluminium chloride and Folin-Ciocalteu methods, respectively. The extract showed antibacterial activity with MIC ranging from 3.60 to 461.75 µg/ml and MBC ranging from 461.75 to >461.75 µg/ml. Furthermore, it significantly reduced biofilm biomass and cell viability in a dose-dependent manner. Biological activities of J. regia extract may be due to its high flavonoid and phenolic contents. The obtained results are promising and they deserve further scientific investigations.},
}
@article {pmid31396394,
year = {2019},
author = {Cameron, LC and Bonis, B and Phan, CQ and Kent, LA and Lee, AK and Hunter, RC},
title = {A putative enoyl-CoA hydratase contributes to biofilm formation and the antibiotic tolerance of Achromobacter xylosoxidans.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {20},
doi = {10.1038/s41522-019-0093-6},
pmid = {31396394},
issn = {2055-5008},
abstract = {Achromobacter xylosoxidans has attracted increasing attention as an emerging pathogen in patients with cystic fibrosis. Intrinsic resistance to several classes of antimicrobials and the ability to form robust biofilms in vivo contribute to the clinical manifestations of persistent A. xylosoxidans infection. Still, much of A. xylosoxidans biofilm formation remains uncharacterized due to the scarcity of existing genetic tools. Here we demonstrate a promising genetic system for use in A. xylosoxidans; generating a transposon mutant library which was then used to identify genes involved in biofilm development in vitro. We further described the effects of one of the genes found in the mutagenesis screen, encoding a putative enoyl-CoA hydratase, on biofilm structure and tolerance to antimicrobials. Through additional analysis, we find that a fatty acid signaling compound is essential to A. xylosoxidans biofilm ultrastructure and maintenance. This work describes methods for the genetic manipulation of A. xylosoxidans and demonstrated their use to improve our understanding of A. xylosoxidans pathophysiology.},
}
@article {pmid31396193,
year = {2019},
author = {Woodburn, KW and Jaynes, JM and Clemens, LE},
title = {Evaluation of the Antimicrobial Peptide, RP557, for the Broad-Spectrum Treatment of Wound Pathogens and Biofilm.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1688},
doi = {10.3389/fmicb.2019.01688},
pmid = {31396193},
issn = {1664-302X},
abstract = {The relentless growth of multidrug resistance and generation of recalcitrant biofilm are major obstacles in treating wounds, particularly in austere military environments where broad-spectrum pathogen coverage is needed. Designed antimicrobial peptides (dAMPs) are constructed analogs of naturally occurring AMPs that provide the first line of defense in many organisms. RP557 is a dAMP resulting from iterative rational chemical structural analoging with endogenous AMPs, human cathelicidin LL-37 and Tachyplesin 1 and the synthetic D2A21 used as structural benchmarks. RP557 possesses broad spectrum activity against Gram-positive and Gram-negative bacteria and fungi, including recalcitrant biofilm with substantial selective killing over bacterial cells compared to mammalian cells. RP557 did not induce resistance following chronic passages of Pseudomonas aeruginosa and Staphylococcus aureus at subinhibitory concentrations, whereas concurrently run conventional antibiotics, gentamycin, and clindamycin, did. Furthermore, RP557 was able to subsequently eliminate the generated gentamycin resistant P. aeruginosa and clindamycin resistant S. aureus strains without requiring an increase in minimum inhibitory concentration (MIC) concentrations. RP557 was evaluated further in a MRSA murine wound abrasion infection model with a topical application of 0.2% RP557, completely eliminating infection. If these preclinical results are translated into the clinical setting, RP557 may become crucial for the empirical broad-spectrum treatment of wound pathogens, so that infections can be reduced to a preventable complication of combat-related injuries.},
}
@article {pmid31396166,
year = {2019},
author = {Yan, S and Wu, G},
title = {Can Biofilm Be Reversed Through Quorum Sensing in Pseudomonas aeruginosa?.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1582},
doi = {10.3389/fmicb.2019.01582},
pmid = {31396166},
issn = {1664-302X},
abstract = {Pseudomonas aeruginosa is a Gram-negative bacterium causing diseases in plants, animals, and humans, and its drug resistance is a major concern in medical care. Biofilms play an important role in P. aeruginosa drug resistance. Three factors are most important to induce biofilm: quorum sensing (QS), bis-(3'-5')-cyclic diguanosine monophosphate (c-di-GMP), and small RNAs (sRNAs). P. aeruginosa has its own specific QS system (PQS) besides two common QS systems, LasI-LasR and RhlI-RhlR, in bacteria. PQS is interesting not only because there is a negative regulation from RhlR to pqsR but also because the null mutation in PQS leads to a reduced biofilm formation. Furthermore, P. aeruginosa dispersed cells have physiological features that are distinct between the planktonic cells and biofilm cells. In response to a low concentration of c-di-GMP, P. aeruginosa cells can disperse from the biofilms to become planktonic cells. These raise an interesting hypothesis of whether biofilm can be reversed through the QS mechanism in P. aeruginosa. Although a single factor is certainly not sufficient to prevent the biofilm formation, it necessarily explores such possibility. In this hypothesis, the literature is analyzed to determine the negative regulation pathways, and then the transcriptomic data are analyzed to determine whether this hypothesis is workable or not. Unexpectedly, the transcriptomic data reveal a negative regulation between lasI and psqR. Also, the individual cases from transcriptomic data demonstrate the negative regulations of PQS with laslI, laslR, rhlI, and rhlR under different experiments. Based on our analyses, possible strategies to reverse biofilm formation are proposed and their clinic implications are addressed.},
}
@article {pmid31394187,
year = {2019},
author = {Barrios-Gumiel, A and Sanchez-Nieves, J and Pérez-Serrano, J and Gómez, R and de la Mata, FJ},
title = {PEGylated AgNP covered with cationic carbosilane dendrons to enhance antibacterial and inhibition of biofilm properties.},
journal = {International journal of pharmaceutics},
volume = {569},
number = {},
pages = {118591},
doi = {10.1016/j.ijpharm.2019.118591},
pmid = {31394187},
issn = {1873-3476},
abstract = {This work focuses on preparation of silver nanoparticles (AgNP) covered with cationic carbosilane dendrons and poly(ethylene glycol) (PEG). It is well known that AgNP and cationic carbosilane dendritic systems present antibacterial properties. On the other hand, PEG ligand provides antifouling properties and improved biocompatibility. Hence, combination of both ligands, carbosilane dendrons and PEG, on the AgNP surface can be a way to improve antibacterial capacity of AgNP. The new family of heterofunctionalized AgNP has been directly synthesized using silver precursor and cationic carbosilane dendrons and PEG ligands containing a thiol moiety. AgNP were characterized by TEM, TGA, UV, 1H NMR, DLS, Z potential, XRD. The antibacterial capacity of these systems was evaluated against E. coli and S. aureus. The results confirmed the influence of both silver core and cationic carbosilane dendrons on the activity of these systems. The behaviour obtained for PEGylated systems were slightly lower than for non-PEGylated AgNP. However, hemolysis assays demonstrated that this decrease was compensated for by the greater biocompatibility. To more completely characterize the improvements of PEGylation on dendronized AgNP, one non-PEGylated and one PEGylated AgNP were tested for resistance in a planktonic state. Both AgNPs barely affected the minimum inhibitory concentration (MIC) whereas reference antibiotics generated significant resistance. In addition, relevant improvement in biofilm inhibition was achieved by dendronized AgNP after PEGylation.},
}
@article {pmid31393795,
year = {2019},
author = {Fronzo, C},
title = {An early, biofilm-focused wound management approach.},
journal = {Journal of wound care},
volume = {28},
number = {8},
pages = {524-526},
doi = {10.12968/jowc.2019.28.8.524},
pmid = {31393795},
issn = {0969-0700},
abstract = {Wound care experts at the 2019 EWMA conference described the need to adopt biofilm-based wound care, the case for silver dressings, the importance of early intervention and the benefits of effective antibiofilm technologies. Camila Fronzo, JWC chief sub editor, summarises the main points.},
}
@article {pmid31392229,
year = {2019},
author = {Abbaszadeh, A and Tehmasebi-Foolad, A and Rajabzadeh, A and Beigi-Brojeni, N and Zarei, L},
title = {Effects of Chitosan/Nano Selenium Biofilm on Infected Wound Healing in Rats; An Experimental Study.},
journal = {Bulletin of emergency and trauma},
volume = {7},
number = {3},
pages = {284-291},
doi = {10.29252/beat-0703012},
pmid = {31392229},
issn = {2322-2522},
abstract = {Objective: The present study was aimed at assessment of effect of application of Chitosan/Nano Selenium biofilm on infected wound healing in rats.<br><br>Methods: Sixty-eight male Wistar rats were randomized into four groups of 17 animals each. In group I (Normal) the wounds were created with no infection. In group II (MRSA), the wounds were infected with methicillin resistant Staphylococcus aureus(MRSA). In group III (MRSA/CHIT), animals with infected wounds were dressed with chitosan biofilm only. In group IV (MRSA/CHIT/NS), animals with infected wounds were dressed with Chitosan/Nano Selenium biofilm.<br><br>Results: There were significant differences in comparisons of group IV and other groups, particularly in terms of cellular infiltration and neovascularization. During the study period, scores for neovascularization was significantly higher in group IV rats than other groups (P<0.05). Polymorphonuclear (PMN) and mononuclear (MNC) cell count and fibroblast cell proliferation in group IV were significantly higher than those of other experimental groups (P<0.05).<br><br>Conclusion: Chitosan/Nano Selenium biofilm resulted in significant improvement in histopathological indices in full thickness infected wound healing.},
}
@article {pmid31391891,
year = {2019},
author = {Cox, KE and Melander, C},
title = {Anti-biofilm activity of quinazoline derivatives against Mycobacterium smegmatis.},
journal = {MedChemComm},
volume = {10},
number = {7},
pages = {1177-1179},
doi = {10.1039/c9md00156e},
pmid = {31391891},
issn = {2040-2511},
abstract = {Bacteria employ a number of mechanisms to resist the effects of antibiotics, including the formation of biofilms. We explored the anti-biofilm capabilities of a library of compounds based upon a 2-aminoquinazoline (2-AQ) scaffold against Mycobacterium smegmatis. This study resulted in the identification of 2-AQ derivatives with biofilm inhibition activity against M. smegmatis.},
}
@article {pmid31390848,
year = {2019},
author = {Pennone, V and Sanz-Gaitero, M and O'Connor, P and Coffey, A and Jordan, K and van Raaij, MJ and McAuliffe, O},
title = {Inhibition of L. monocytogenes Biofilm Formation by the Amidase Domain of the Phage vB_LmoS_293 Endolysin.},
journal = {Viruses},
volume = {11},
number = {8},
pages = {},
doi = {10.3390/v11080722},
pmid = {31390848},
issn = {1999-4915},
support = {14/F/881//Food Institutional Research Measure/ ; },
abstract = {Listeria monocytogenes is a ubiquitous Gram-positive bacterium that is a major concern for food business operators because of its pathogenicity and ability to form biofilms in food production environments. Bacteriophages (phages) have been evaluated as biocontrol agents for L. monocytogenes in a number of studies and, indeed, certain phages have been approved for use as anti-listerial agents in food processing environments (ListShield and PhageGuard Listex). Endolysins are proteins produced by phages in the host cell. They cleave the peptidoglycan cell wall, thus allowing release of progeny phage into the environment. In this study, the amidase domain of the phage vB_LmoS_293 endolysin (293-amidase) was cloned and expressed in Escherichia. coli(E. coli). Muralytic activity at different concentrations, pH and temperature values, lytic spectrum and activity against biofilms was determined for the purified 293-amidase protein. The results showed activity on autoclaved cells at three different temperatures (20 °C, 37 °C and 50 °C), with a wider specificity (L. monocytogenes 473 and 3099, a serotype 4b and serogroup 1/2b-3b-7, respectively) compared to the phage itself, which targets only L. monocytogenes serotypes 4b and 4e. The protein also inhibits biofilm formation on abiotic surfaces. These results show the potential of using recombinant antimicrobial proteins against pathogens in the food production environment.},
}
@article {pmid31389671,
year = {2019},
author = {Martínez-García, S and Ortega-Peña, S and De Haro-Cruz, MJ and Aguilera-Arreola, MG and Alcántar-Curiel, MD and Betanzos-Cabrera, G and Jan-Roblero, J and Pérez-Tapia, SM and Rodríguez-Martínez, S and Cancino-Diaz, ME and Cancino-Diaz, JC},
title = {Non-biofilm-forming commensal Staphylococcus epidermidis isolates produce biofilm in the presence of trypsin.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e906},
doi = {10.1002/mbo3.906},
pmid = {31389671},
issn = {2045-8827},
support = {269242//Consejo Nacional de Ciencia y Tecnología (CONACyT)/ ; 20181167//SIP-Instituto Politécnico Nacional Mexico/ ; //Instituto Politécnico Nacional fellowships/ ; //Sistema Nacional de Investigadores, CONACyT/ ; //CONACyT/ ; 247489//PDCPN/ ; IN220613//Program UNAM-DGAPA-PAPIIT/ ; },
abstract = {Epidemiological studies comparing clinical and commensal Staphylococcus epidermidis isolates suggest that biofilm formation is a discriminant biomarker. A study showed that four non-biofilm-forming clinical S. epidermidis isolates could form an induced biofilm by trypsin treatment, suggesting that S. epidermidis can form biofilms in a protease-independent way and in a trypsin-induced way. In this study, the trypsin capacity to induce biofilm formation was evaluated in non-biofilm-forming S. epidermidis isolates (n = 133) in order to support this mechanism and to establish the importance of total biofilms (meaning the sum of protease-independent biofilm and trypsin-induced biofilm). Staphylococcus epidermidis isolates from ocular infections (OI; n = 24), prosthetic joint infections (PJI; n = 64), and healthy skin (HS-1; n = 100) were screened for protease-independent biofilm formation according to Christensen's method. The result was that there are significant differences (p < .0001) between clinical (43.2%) and commensal (17%) protease-independent biofilm producers. Meanwhile, non-biofilm-forming isolates were treated with trypsin, and biofilm formation was evaluated by the same method. The number of commensal trypsin-induced biofilm producers significantly increased from 17% to 79%. In contrast, clinical isolates increased from 43.2% to 72.7%. The comparison between clinical and commensal total biofilm yielded no significant differences (p = .392). A similar result was found when different isolation sources were compared (OI vs. HS-1 and PJI vs. HS-1). The genotype icaA- /aap+ was associated with the trypsin-induced biofilm phenotype; however, no correlation was observed between aap mRNA expression and the level of trypsin-induced biofilm phenotype. Studying another group of commensal S. epidermidis non-biofilm-forming isolates (HS-2; n = 139) from different body sites, it was found that 70 isolates (60.3%) formed trypsin-induced biofilms. In conclusion, trypsin is capable of inducing biofilm production in non-biofilm-forming commensal S. epidermidis isolates with the icaA- /aap+ genotype, and there is no significant difference in total biofilms when comparing clinical and commensal isolates, suggesting that total biofilms are not a discriminant biomarker.},
}
@article {pmid31388951,
year = {2019},
author = {Bó, LG and Almeida, RM and Cardoso, CMM and Zavarize, DG and Brum, SS and Mendonça, ARV},
title = {Acetylsalicylic acid biosorption onto fungal-bacterial biofilm supported on activated carbons: an investigation via batch and fixed-bed experiments.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-019-06075-0},
pmid = {31388951},
issn = {1614-7499},
abstract = {This study reports on acetylsalicylic acid (ASA) biosorption onto fungal-bacterial biofilm supported on two types of activated carbons (one commercial type made of coconut fibers, CAC, and one other manufactured from fruit rinds of Hymenaea stigonocarpa Mart., HYAC, which after biofilm inoculation, they were named CAC-b and HYAC-b), via batch and fixed-bed experiments. These materials were characterized by BET Specific Surface Area and Scanning Electronic Microscopy (SEM). Biosorption onto HYAC-b was 57.2% higher than HYAC. Despite presenting the highest biosorption capacity over time (qt = 85.4 ± 0.82 mg g-1), CAC-b had a lower increase in efficiency (32.4%) compared to CAC. Kinetic data from the biosorption experiments responded well to the pseudo-first-order model thus suggests the predominance of physisorption, while without biofilm presence, there was a better agreement with the pseudo-second-order model, suggesting chemisorption. The possible interaction mechanism of ASA to biofilm was attributed to ionic forces between the drug in anionic form and eventual presence of cationic by-products of the biologically active surface metabolism. Biosorption equilibrium data responded better to the Sips model and CAC-b presented the highest biosorption capacity (qe = 292.4 ± 2.01 mg g-1). A combination of faster volumetric flow rates, higher inlet concentrations and shorter beds accelerated the breakthrough time of ASA biosorption in the fixed-bed experiments. These operational conditions affected C/Co ratio in the following magnitude order: volumetric flow rate < inlet concentration < bed height. Breakthrough data responded better to the modified dose-response model compared to Thomas and Yoon-Nelson models.},
}
@article {pmid31385644,
year = {2019},
author = {Quan, K and Zhang, Z and Chen, H and Ren, X and Ren, Y and Peterson, BW and van der Mei, HC and Busscher, HJ},
title = {Artificial Channels in an Infectious Biofilm Created by Magnetic Nanoparticles Enhanced Bacterial Killing by Antibiotics.},
journal = {Small (Weinheim an der Bergstrasse, Germany)},
volume = {},
number = {},
pages = {e1902313},
doi = {10.1002/smll.201902313},
pmid = {31385644},
issn = {1613-6829},
support = {2016YFC1100402//National Key Research and Development Program of China/ ; 21334004//National Natural Science Foundation of China/ ; 11574222//National Natural Science Foundation of China/ ; 21522404//National Natural Science Foundation of China/ ; //UMCG/ ; },
abstract = {The poor penetrability of many biofilms contributes to the recalcitrance of infectious biofilms to antimicrobial treatment. Here, a new application for the use of magnetic nanoparticles in nanomedicine to create artificial channels in infectious biofilms to enhance antimicrobial penetration and bacterial killing is proposed. Staphylococcus aureus biofilms are exposed to magnetic-iron-oxide nanoparticles (MIONPs), while magnetically forcing MIONP movement through the biofilm. Confocal laser scanning microscopy demonstrates artificial channel digging perpendicular to the substratum surface. Artificial channel digging significantly (4-6-fold) enhances biofilm penetration and bacterial killing efficacy by gentamicin in two S. aureus strains with and without the ability to produce extracellular polymeric substances. Herewith, this work provides a simple, new, and easy way to enhance the eradication of infectious biofilms using MIONPs combined with clinically applied antibiotic therapies.},
}
@article {pmid31384892,
year = {2019},
author = {He, ZY and Zhou, W and Huang, ZW and Liang, JP and Jiang, W},
title = {[The effect of Streptococcus mutans luxS gene on mixed-species biofilm communities].},
journal = {Shanghai kou qiang yi xue = Shanghai journal of stomatology},
volume = {28},
number = {2},
pages = {113-117},
pmid = {31384892},
issn = {1006-7248},
abstract = {PURPOSE: To evaluate the effect of S.mutans luxS gene on mixed-species biofilms communities.<br><br>METHODS: Biofilms were formed by S. mutans (wild type strain, its luxS overexpression strain and luxS knockout strain) and Lactobacillus acidophilus (ATCC4356) with a ratio of 1:1 at 37℃ for 4 h, 14 h and 24 h. MTT assay was used to detect the quantification of the biofilms formed. The structures of biofilms were observed under confocal laser scanning microscopy after 24 h, and expression of biofilm-related genes (ftf, smu630, brpA, gbpB, gtfB, vicR, comDE and relA) was investigated by real-time PCR. Statistical analysis was performed with SPSS17.0 software package.<br><br>RESULTS: The results showed that biofilm formed by S. mutans(wild type strain, its luxS overexpression strain and luxS knockout strain) and L.acidophilus after 14 h were 0.481±0.024, 0.591±0.023 and 0.279±0.019, respectively. The same findings were present after 24 h, the biofilm formed by S.mutans overexpression strain with L.acidophilus was higher than wild type strain, and the biofilm formed by knockout strain significantly decreased; but there was no significant difference at 4 h time points. CLSM images revealed that both S.mutans overexpression strain and its wild type strain tended to aggregate into distinct clusters and dense structures, whereas the luxS knockout strain appeared relatively sparse. Compared with wild type strain, all of the genes examined were upregulated in the biofilms formed by the overexpression strain, and were downregulated in the biofilms formed by the luxS mutant strain in mixed-species biofilm.<br><br>CONCLUSIONS: S.mutans luxS gene can affect mixed-species biofilm formation with L.acidophilus, which provides evidences for further study.},
}
@article {pmid31382580,
year = {2019},
author = {Cattò, C and Cappitelli, F},
title = {Testing Anti-Biofilm Polymeric Surfaces: Where to Start?.},
journal = {International journal of molecular sciences},
volume = {20},
number = {15},
pages = {},
doi = {10.3390/ijms20153794},
pmid = {31382580},
issn = {1422-0067},
abstract = {Present day awareness of biofilm colonization on polymeric surfaces has prompted the scientific community to develop an ever-increasing number of new materials with anti-biofilm features. However, compared to the large amount of work put into discovering potent biofilm inhibitors, only a small number of papers deal with their validation, a critical step in the translation of research into practical applications. This is due to the lack of standardized testing methods and/or of well-controlled in vivo studies that show biofilm prevention on polymeric surfaces; furthermore, there has been little correlation with the reduced incidence of material deterioration. Here an overview of the most common methods for studying biofilms and for testing the anti-biofilm properties of new surfaces is provided.},
}
@article {pmid31382523,
year = {2019},
author = {Karampoula, F and Doulgeraki, AI and Fotiadis, C and Tampakaki, A and Nychas, GE},
title = {Monitoring Biofilm Formation and Microbial Interactions that May Occur During a Salmonella Contamination Incident across the Network of a Water Bottling Plant.},
journal = {Microorganisms},
volume = {7},
number = {8},
pages = {},
doi = {10.3390/microorganisms7080236},
pmid = {31382523},
issn = {2076-2607},
support = {380229//European Social Fund/ ; 548//Education and Lifelong Learning/ ; },
abstract = {The present study aims to monitor the ability of Salmonella to colonize and compete as a member of the mixed species biofilm within key points at a water bottling plant, in case of a contamination incident with this major foodborne pathogen. To achieve this goal, bacterial communities throughout the production line were collected and their identities were investigated by microbial counts and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). These bacterial communities alone or along with constructed Salmonellaenterica serovar Typhimurium (ST) fluorescence-based bioreporters were left to form a biofilm on stainless steel for 6 days at 20 °C. ST bioreporters were constructed by introducing plasmids expressing EYFP (enhanced yellow fluorescent protein) fusions of the genes csgB, csrA, sspH2, and fliD into ST 14028S. The bead vortexing-plate counting method was applied for the enumeration of the biofilm population, while the behavior of the bioreporters was evaluated by fluorescence microscopy. From a set of 16 samples that were collected from the plant, species of Citrobacter, Staphylococcus, Pseudomonas, Bacillus, and Exiguobacterium were identified. The presence of these indigenous bacteria neither inhibited nor enhanced the biofilm formation of ST in mixed bacterial communities (p > 0.05). Furthermore, the csrA-based bioreporter was shown to be induced in multispecies biofilms with Citrobacter. In conclusion, this study enhanced our knowledge of bacterial interactions occurring within a biofilm in a water bottling plant.},
}
@article {pmid31382160,
year = {2019},
author = {Martins, ML and Monteiro, ASN and Guimarães, JEC and Guimarães, MBCT and da Silva, RF and Cabral, LM and Farah, A and dePaula, J and Romanos, MTV and Maia, LC and Cavalcanti, YW and Fonseca-Gonçalves, A},
title = {Cytotoxic and antibacterial effect of a red propolis mouthwash, with or without fluoride, on the growth of a cariogenic biofilm.},
journal = {Archives of oral biology},
volume = {107},
number = {},
pages = {104512},
doi = {10.1016/j.archoralbio.2019.104512},
pmid = {31382160},
issn = {1879-1506},
abstract = {OBJECTIVE: To evaluatein vitro the antibacterial activity, the antibiofilm effect and the cytotoxic potential of mouthwashes containing Brazilian red propolis with or without fluoride.<br><br>METHODS: The minimum inhibitory and bactericidal concentrations (MIC and MBC) against S. mutans, S. sanguinis, S. salivarius and L. casei were determined for RPE mouthwashes. A cariogenic biofilm with the aforementioned bacteria was formed over cellulose membrane disks (N = 30, 13 mm), which were submitted for 1 min to the following mouthwashes: plain mouthwash base; 0.05% NaF; 0.8% RPE; 0.8% RPE + 0.05% NaF and 0.12% chlorhexidine (CHX). The bacterial viability and the production of extracellular polysaccharide (EPS) were measured. Cytotoxic potential of the mouthwashes was also evaluated. For bacterial viability and EPS production, Mann-Withney and one-way ANOVA tests were performed followed by Tukey, with results considered significant when p ≤ 0.05.<br><br>RESULTS: MIC and MBC values of RPE mouthwashes ranged from 7.44 to 29.76 mg/mL and from 7.44 to ≥59.52 mg/mL, respectively, presenting better action against S. salivarius. RPE mouthwashes showed 44% of viable cells after 1 min of contact with fibroblasts. RPE (7.74) had the greatest reduction of viable total microorganisms and did not differ from the RPE + NaF (7.95) (p = 0.292). CHX (7.54) was the most effective in reducing Streptococcus spp, but did not differ from RPE (p = 0.521) and RPE + NaF (p = 0.238). There was no difference between the treatments regarding EPS production.<br><br>CONCLUSION: RPE and RPE + NaF mouthwash showed similar antibacterial activity, toxicity level and antibiofilm effect compared to CHX.},
}
@article {pmid31380192,
year = {2019},
author = {Lei, W and Bruchmann, J and Rüping, JL and Levkin, PA and Schwartz, T},
title = {Biofilm Bridges Forming Structural Networks on Patterned Lubricant-Infused Surfaces.},
journal = {Advanced science (Weinheim, Baden-Wurttemberg, Germany)},
volume = {6},
number = {13},
pages = {1900519},
doi = {10.1002/advs.201900519},
pmid = {31380192},
issn = {2198-3844},
abstract = {Despite many decades of research, biofilm architecture and spreading mechanisms are still not clear because of the heterogenous 3D structure within biofilms. Here, patterned &quot;slippery&quot; lubricant-infused porous surfaces are utilized to study biofilm structure of Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Staphylococcus aureus. It is found that bacteria are able to spread over bacteria-repellent lubricant-infused regions by using a mechanism, termed &quot;biofilm bridges&quot;. Here, it is demonstrated that bacteria use bridges to form interconnected networks between distant biofilm colonies. Detailed structure of bridges shows a spatial distribution of bacteria with an accumulation of respiratory active bacteria and biomass in the bridges. The core-shell structure of bridges formed by two-species mixed population is illustrated. It is demonstrated that eDNA and nutrients have a strong effect on biofilm bridges formation. Thus, it is believed that biofilm bridging is important to reveal the structure and communication within biofilms.},
}
@article {pmid31379772,
year = {2019},
author = {Josse, J and Valour, F and Maali, Y and Diot, A and Batailler, C and Ferry, T and Laurent, F},
title = {Interaction Between Staphylococcal Biofilm and Bone: How Does the Presence of Biofilm Promote Prosthesis Loosening?.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1602},
doi = {10.3389/fmicb.2019.01602},
pmid = {31379772},
issn = {1664-302X},
abstract = {With the aging of population, the number of indications for total joint replacement is continuously increasing. However, prosthesis loosening can happen and is related to two major mechanisms: (1) aseptic loosening due to prosthesis micromotion and/or corrosion and release of wear particles from the different components of the implanted material and (2) septic loosening due to chronic prosthetic joint infection (PJI). The &quot;aseptic&quot; character of prosthesis loosening has been challenged over the years, especially considering that bacteria can persist in biofilms and be overlooked during diagnosis. Histological studies on periprosthetic tissue samples reported that macrophages are the principle cells associated with aseptic loosening due to wear debris. They produce cytokines and favor an inflammatory environment that induces formation and activation of osteoclasts, leading to bone resorption and periprosthetic osteolysis. In PJIs, the presence of infiltrates of polymorphonuclear neutrophils is a major criterion for histological diagnosis. Neutrophils are colocalized with osteoclasts and zones of osteolysis. A similar inflammatory environment also develops, leading to bone resorption through osteoclasts. Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus lugdunensis are the main staphylococci observed in PJIs. They share the common feature to form biofilm. For S. aureus and S. epidermidis, the interaction between biofilm and immunes cells (macrophages and polymorphonuclear neutrophils) differs regarding the species. Indeed, the composition of extracellular matrix of biofilm seems to impact the interaction with immune cells. Recent papers also reported the major role of myeloid-derived suppressor cells in biofilm-associated PJIs with S. aureus. These cells prevent lymphocyte infiltration and facilitate biofilm persistence. Moreover, the role of T lymphocytes is still unclear and potentially underestimates. In this review, after introducing the cellular mechanism of aseptic and septic loosening, we will focus on the interrelationships between staphylococcal biofilm, immune cells, and bone cells.},
}
@article {pmid31378149,
year = {2019},
author = {Wang, W and Nemati, M},
title = {Co-biodegradation of naphthenic acids in anoxic denitrifying biofilm reactors.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-17},
doi = {10.1080/09593330.2019.1650122},
pmid = {31378149},
issn = {1479-487X},
abstract = {Anoxic co-biodegradation of linear and cyclic naphthenic acids (NAs) namely octanoic acid, trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA), cis- and trans-4-methyl-1-cyclohexane-acetic acids (cis-4MCHAA and trans-4MCHAA) was investigated in denitrifying biofilm reactors. In all evaluated compositions, co-biodegradation of NAs was coupled to denitrification, with octanoic acid showing the fastest biodegradation rate (1180.4 mg L-1 h-1 at loading rate of 1180.4 mg L-1 h-1), followed by trans-4MCHCA (398.1 mg L-1 h-1 at loading rate of 435.8 mg L-1 h-1), trans-4MCHAA (25.7 mg L-1 h-1 at loading rate of 221.7 mg L-1 h-1), and cis-4MCHAA (5.3 mg L-1 h-1 at loading rate of 16.9 mg L-1 h-1). Biodegradation of octanoic acid and trans-4MCHCA were not influenced by the presence of recalcitrant NAs (cis- and trans-4MCHAA). Co-biodegradation of cis- and trans-4MCHAA with octanoic acid, trans-4MCHCA, or their combination enhanced the biodegradability of these recalcitrant NAs, with the positive impact being more pronounced for trans-4MCHCA. Finally anoxic co-biodegradation of NAs under denitrifying conditions proceeded at rates that were faster than the aerobic rates obtained in similar mixtures. Anoxic biodegradation, therefore, is an effective alternative for in situ treatment of oil sands process water in anoxic stabilization ponds amended with nitrate, or as an ex situ treatment approach in denitrifying bioreactors whereby the cost and technical challenges of aeration are eliminated.},
}
@article {pmid31376667,
year = {2019},
author = {Li, X and Wang, X and Lee, DJ and Yan, WM},
title = {Highly heterogeneous interior structure of biofilm wastewater for enhanced pollutant removals.},
journal = {Bioresource technology},
volume = {291},
number = {},
pages = {121919},
doi = {10.1016/j.biortech.2019.121919},
pmid = {31376667},
issn = {1873-2976},
abstract = {Biofilm processes are widely used in wastewater treatment. The biofilm has highly heterogeneous interior structure, which can significantly affect the transport processes and the biological reactions over the biofilm. This study for the first time detailed the complicated velocity and concentration fields of substrate in a real biofilm structure. With a real biofilm interior being profiled and meshed to numerical solutions, the flow-through mode has significant distortion of inflow velocity fields and concentration distributions, which lead to enhanced biological reactions at regimes nearby major pores. Conversely, the crossflow mode depends weakly on the biofilm interior structure. The uniform biofilm model fails to describe the real biofilm processes. Future research needs based on real biofilm structures were discussed.},
}
@article {pmid31376126,
year = {2019},
author = {Kumari, S and Das, S},
title = {Expression of metallothionein encoding gene bmtA in biofilm-forming marine bacterium Pseudomonas aeruginosa N6P6 and understanding its involvement in Pb(II) resistance and bioremediation.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-019-05916-2},
pmid = {31376126},
issn = {1614-7499},
support = {BT/PR14998/GBD/27/279/2010//Department of Biotechnology , Ministry of Science and Technology/ ; },
abstract = {The genetic basis and biochemical aspects of heavy metal endurance abilities have been precisely studied in planktonic bacteria; however, in nature, bacteria mostly grows as surface-attached communities called biofilms. A hallmark trait of biofilm is increased resistance to heavy metals compared with the resistance of planktonic bacteria. A proposed mechanism that contributes to this increased resistance is the enhanced expression of metal-resistant genes. bmtA gene coding for metallothionein protein is one such metal-resistant gene found in many bacterial spp. In the present study, lead (Pb) remediation potential of a biofilm-forming marine bacterium Pseudomonas aeruginosa N6P6 was explored. Biofilm-forming marine bacterium P. aeruginosa N6P6 possess bmtA gene and shows resistance towards many heavy metals, i.e., Pb, Cd, Hg, Cr, and Zn. The expression of metallothionein encoding gene bmtA is significantly high in 48-h-old biofilm culture (11. 4 fold) followed by 24-h-old biofilm culture of P. aeruginosa N6P6 (4.7 fold) (P < 0.05). However, in the case of planktonically grown culture of P. aeruginosa N6P6, the highest expression of bmtA gene was observed in 24-h-old culture. The expression of bmtA also increased significantly with increase in Pb concentration up to 800 ppm. CSLM analysis indicated significant reduction in the raw integrated density of biofilm-associated lipids and polysaccharides (PS) of P. aeruginosa N6P6 biofilm grown in Pb (sub-lethal concentration)-amended medium (P < 0.05), whereas no significant reduction was observed in the raw integrated density of EPS-associated protein. The role of bmtA gene as Pb(II)-resistant determinant was characterized by overexpressing the bmtA gene derived from P. aeruginosa N6P6 in Escherichia coli BL21(DE3). ESI-MS and SDS-PAGE analyses validated the presence of 11.5-kDa MT protein isolated from Pb(II)-induced recombinant E. coli BL21(DE3) harboring bmtA gene.},
}
@article {pmid31375964,
year = {2019},
author = {Fonseca, DL and Bassin, JP},
title = {Investigating the most appropriate methods for attached solids determination in moving-bed biofilm reactors.},
journal = {Bioprocess and biosystems engineering},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00449-019-02182-x},
pmid = {31375964},
issn = {1615-7605},
abstract = {Moving-bed biofilm reactors (MBBR) have been employed worldwide as an efficient technology for the treatment of a diverse set of wastewaters. Although the attached biomass represents the major fraction of solids in MBBR systems, there is still no standard for its reliable quantification. An extensive literature review indicated that several methods for attached biomass assessment are applied, hindering the comparability of results issued from different studies. Therefore, the most reported methods for biofilm quantification in the MBBR literature were compared using three different carriers. The results revealed that the performance of each method was biased depending on the carrier type and shape. Moreover, differences in total attached solids (TAS) concentrations varied from 13% up to more than 90%, depending on the employed method for a given carrier. Overall, direct weighing of the carrier containing the biofilm, accounting for the clean carrier weight, and manual extraction of the biofilm, preceded or not by sonication for at least 15 min, were the most suitable techniques for assessing TAS and the volatile/total solids ratio in non-porous medias, respectively. The results here presented may be used as a frame of reference for standardization of the methods for assessing the biofilm mass in MBBR carriers.},
}
@article {pmid31374264,
year = {2019},
author = {Sherly Carolyn, J and Selva Raj, D and Malaikozhundan, B and Govindarajan, M and Alharbi, NS and Kadaikunnan, S and Khaled, JM and Al-Anbr, MN and Alobaidi, AS and Vaseeharan, B},
title = {Anti-cancer, anti-biofilm, and anti-inflammatory properties of Hen's albumen: a photodynamic approach.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.07.026},
pmid = {31374264},
issn = {1873-1597},
abstract = {The albumen plays a major role in the protection of eggs against microorganisms. It contains an arsenal of natural antimicrobial molecules and antibacterial proteins, including the well-known ovotransferrin and lysozyme, which exert their activities against a range of bacteria. In the present study, the hen's albumen extract treated with the dried insect body of blister beetle M. pustulata was assessed for antibacterial, antibiofilm, anti-inflammatory and anti-proliferative activity. The zone of inhibition against Gram positive E. faecalis and S. aureus was 10.8 mm and 12.1 mm respectively at 100 µg mL-1. However, it was 13.6 mm and 15.3 mm for Gram negative P. aeruginosa and P. vulgaris respectively. The biofilm of tested bacteria was significantly inhibited at 100 µg mL-1. The hydrophobicity of bacterial biofilms was considerably condensed after treatment with the hen's albumen extracts at 100 µg mL-1. The anti-inflammatory activity of hen's albumen extracts was confirmed by the inhibition of cyclooxygenase (COX) enzyme to 84.91% at 100 μg mL-1 with the relative IC50 of 8.26 μg mL-1. The albumen extract effectively inhibited the viability (23.61%) of HepG2 hepatic cancer cells at 100 µg mL-1. The anti-proliferative activity of the albumen extracts was further revealed by the induction of HepG2 apoptotic cell morphology. This study concludes that the hen's albumen extract treated with M. pustulata is a natural therapeutic agent to treat biofilm associated clinical bacteria, inflammations and human hepatic cancer cells.},
}
@article {pmid31373891,
year = {2019},
author = {Bottino, MA and Pereira, S and Amaral, M and Milhan, N and Pereira, CA and Camargo, S and Carvalho, A and Melo, RM},
title = {Streptococcus mutans Biofilm Formation and Cell Viability on Polymer-infiltrated Ceramic and Yttria-stabilized Polycrystalline Zirconium Dioxide Ceramic.},
journal = {Operative dentistry},
volume = {},
number = {},
pages = {},
doi = {10.2341/18-278-L},
pmid = {31373891},
issn = {1559-2863},
abstract = {OBJECTIVE: The aim of this study was to investigate the biofilm formation and cell viability of a polymer-infiltrated ceramic (PIC) and an yttria-stabilized polycrystalline zirconium dioxide ceramic (Y-TZP). The null hypothesis was that there would be no difference in biofilm formation and cell viability between the materials.<br><br>METHODS AND MATERIALS: Streptococcus mutans biofilm was analyzed with scanning electron microscopy (SEM), confocal laser scanning microscopy, and colony counting (colony-forming units/mL). The cell viability (fibroblasts) of both materials was measured with 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium) (MTT) test. Roughness measurements were also performed.<br><br>RESULTS: The PIC displayed higher roughness but showed similar colony-forming units and biovolume values to those of Y-TZP. SEM showed a higher amount of adhered fibroblasts on the PIC surface on the first day and similar amounts on both materials after seven days. Moreover, the materials were biocompatible with human fibroblasts.<br><br>CONCLUSION: PIC and Y-TZP are biocompatible and present the same characteristics for biofilm formation; therefore, they are indicated for indirect restorations and implant abutments.},
}
@article {pmid31373035,
year = {2019},
author = {Simkins, JW and Stewart, PS and Codd, SL and Seymour, JD},
title = {Non-invasive imaging of oxygen concentration in a complex in vitro biofilm infection model using 19 F MRI: Persistence of an oxygen sink despite prolonged antibiotic therapy.},
journal = {Magnetic resonance in medicine},
volume = {82},
number = {6},
pages = {2248-2256},
doi = {10.1002/mrm.27888},
pmid = {31373035},
issn = {1522-2594},
support = {//National Science Foundation./ ; R01 GM109452/GM/NIGMS NIH HHS/United States ; R01GM109452/NH/NIH HHS/United States ; },
abstract = {PURPOSE: Oxygen availability is a critical determinant of microbial biofilm activity and antibiotic susceptibility. However, measuring oxygen gradients in these systems remains difficult, with the standard microelectrode approach being both invasive and limited to single-point measurement. The goal of the study was to develop a 19 F MRI approach for 2D oxygen mapping in biofilm systems and to visualize oxygen consumption behavior in real time during antibiotic therapy.<br><br>METHODS: Oxygen-sensing beads were created by encapsulating an emulsion of oxygen-sensing fluorocarbon into alginate gel. Escherichia coli biofilms were grown in and on the alginate matrix, which was contained inside a packed bed column subjected to nutrient flow, mimicking the complex porous structure of human wound tissue, and subjected to antibiotic challenge.<br><br>RESULTS: The linear relationship between 19 F spin-lattice relaxation rate R1 and local oxygen concentration permitted noninvasive spatial mapping of oxygen distribution in real time over the course of biofilm growth and subsequent antibiotic challenge. This technique was used to visualize persistence of microbial oxygen respiration during continuous gentamicin administration, providing a time series of complete spatial maps detailing the continued bacterial utilization of oxygen during prolonged chemotherapy in an in vitro biofilm model with complex spatial structure.<br><br>CONCLUSIONS: Antibiotic exposure temporarily causes oxygen consumption to enter a pseudosteady state wherein oxygen distribution becomes fixed; oxygen sink expansion resumes quickly after antibiotic clearance. This technique may provide valuable information for future investigations of biofilms by permitting the study of complex geometries (typical of in vivo biofilms) and facilitating noninvasive oxygen measurement.},
}
@article {pmid31372943,
year = {2019},
author = {Ansari, FA and Ahmad, I},
title = {Isolation, functional characterization and efficacy of biofilm-forming rhizobacteria under abiotic stress conditions.},
journal = {Antonie van Leeuwenhoek},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10482-019-01306-3},
pmid = {31372943},
issn = {1572-9699},
abstract = {Abiotic stresses such as salinity, drought and excessive heat are associated with significant loss of crop productivity globally, and require effective strategies for their reduction or tolerance. Biofilm-forming rhizobacteria, which harbor multifarious plant growth promoting traits and tolerance to abiotic stress, are believed to benefit plant health and production even under environmental stresses. The primary objective of this study was to investigate indigenous biofilm-forming rhizobacteria (Pseudomonas spp., Bacillus sp., Pantoea sp., Brevibacterium sp. and Acinetobacter sp.) for their functional diversity relevant to plant growth promoting activities, biofilm development and tolerance to abiotic stress conditions. The most promising isolates among FAP1, FAP2, FAP3, FAP4, FAP5, FAP10, FAB1, FAB3 and FAA1 were selected. Rhizobacteria exhibited high tolerance to salinity (1.5 M NaCl) and drought stress (up to 55% PEG-6000) conditions in vitro. The isolates demonstrated varying levels of PGP activities (IAA production and phosphate solubilization), biofilm development, and production of alginate and exopolysaccharides in the presence of salinity, drought stress and elevated temperature. Further efficacy of the isolates was demonstrated by inoculating to wheat (Triticum aestivum L.) plants in greenhouse conditions under both normal and drought stress for up to 30 days inoculation. The plant growth potential of the isolates was in the order of FAP3 > FAB3 > FAB1 > FAP10 > FAP5 > FAP4 > FAA1 > FAP2 > FAP1. The present study resulted in successful selection of promising PGPR as identified by 16S rRNA gene sequence analysis. Field study is needed to evaluate their relative performance in both 'normal' and stressed environments in order to be exploited for plant stress management.},
}
@article {pmid31371744,
year = {2019},
author = {Stępień-Pyśniak, D and Hauschild, T and Kosikowska, U and Dec, M and Urban-Chmiel, R},
title = {Biofilm formation capacity and presence of virulence factors among commensal Enterococcus spp. from wild birds.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {11204},
doi = {10.1038/s41598-019-47602-w},
pmid = {31371744},
issn = {2045-2322},
abstract = {Enterococci are opportunistic pathogens that can form biofilms during infections and many virulence determinants are involved in this process. Although the virulence factors are often analysed in Enterococcus spp. from humans and food animals, little is known about gut enterococcal isolates from wild birds. Therefore, the determination of virulence factors among enterococci isolated from wild birds may provide new information about a possible source of infection for humans and animals or vice versa via the environment. We analysed different phenotypic and genotypic traits in enterococci from wild birds related to potential virulence in humans and animals and to evaluate biofilm formation and its relationship to virulence genes. The E. faecalis isolates were characterised by greater frequency of biofilm formation in BHI than E. faecium. There was a correlation between hydrophobicity and biofilm formation in BHI broth in E. faecalis. None of the isolates was haemolytic. The presence of some adhesion and gelatinase genes was detected in biofilm-positive isolates. The enterococcal pathogenic factors (esp, hyl, and cyl operon genes) did not seem to be necessary or sufficient for production of biofilm by analysed bacteria. Enterococcus species isolated from wild birds should be considered as a possible source of some virulence determinants.},
}
@article {pmid31370119,
year = {2019},
author = {Song, YJ and Yu, HH and Kim, YJ and Lee, NK and Paik, HD},
title = {Anti-Biofilm Activity of Grapefruit Seed Extract against Staphylococcus aureus and Escherichia coli.},
journal = {Journal of microbiology and biotechnology},
volume = {29},
number = {8},
pages = {1177-1183},
doi = {10.1041/jmb.1905.05022},
pmid = {31370119},
issn = {1738-8872},
abstract = {Grapefruit seed extract (GSE) is a safe and effective preservative that is used widely in the food industry. However, there are few studies addressing the anti-biofilm effect of GSE. In this study, the anti-biofilm effect of GSE was investigated against biofilm-forming strains of Staphylococcus aureus and Escherichia coli. The GSE minimum inhibitory concentration (MIC) for S. aureus and E. coli were 25 μg/ml and 250 μg/ml, respectively. To investigate biofilm inhibition and degradation effect, crystal violet assay and stainless steel were used. Biofilm formation rates of four strains (S. aureus 7, S. aureus 8, E. coli ATCC 25922, and E. coli O157:H4 FRIK 125) were 55.8%, 70.2%, 55.4%, and 20.6% at 1/2 × MIC of GSE, respectively. The degradation effect of GSE on biofilms attached to stainless steel coupons was observed (≥ 1 log CFU/coupon) after exposure to concentrations above the MIC for all strains and 1/2 × MIC for S. aureus 7. In addition, the specific mechanisms of this anti-biofilm effect were investigated by evaluating hydrophobicity, auto-aggregation, exopolysaccharide (EPS) production rate, and motility. Significant changes in EPS production rate and motility were observed in both S. aureus and E. coli in the presence of GSE, while changes in hydrophobicity were observed only in E. coli. No relationship was seen between auto-aggregation and biofilm formation. Therefore, our results suggest that GSE might be used as an anti-biofilm agent that is effective against S. aureus and E. coli.},
}
@article {pmid31368074,
year = {2019},
author = {Zhou, JH and Yu, HC and Ye, KQ and Wang, HY and Ruan, YJ and Yu, JM},
title = {Optimized aeration strategies for nitrogen removal efficiency: application of end gas recirculation aeration in the fixed bed biofilm reactor.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-019-06050-9},
pmid = {31368074},
issn = {1614-7499},
support = {51708499//National Natural Science Foundation of China/ ; 21576241//National Natural Science Foundation of China/ ; 21776262//National Natural Science Foundation of China/ ; 20180533B03//Hangzhou Agricultural and Social Development Research Program/ ; },
abstract = {Aeration strategy played an important role in reactor performance. In this study, when superficial upflow air velocity (SAV) decreased from 0.16 to 0.08 cm s-1, low dissolved oxygen concentration (DO) of 2.0 mg L-1 occurred in reactor. The required depth for anoxic microenvironment in biofilm decreased from 902.3 to 525.9 μm, which enhanced the growth of denitrifying bacteria and total nitrogen (TN) removal efficiency. However, decreasing aeration intensity resulted in insufficient hydraulic shear stress, which led to weak biofilm matrix structure. Mass biofilm detachment and reactor deterioration then occurred after 87 days of operation. An end gas recirculation aeration strategy was proposed to separately manipulate DO and aeration intensity. Low DO and high aeration intensity were simultaneously achieved, which enhanced the metabolism of denitrifying bacteria (such as Flavobacterium sp., Pseudorhodobacter sp., and Dok59 sp.) and EPS-producing bacteria (such as Zoogloea sp. and Rhodobacter sp.). Consequently, high TN removal performance (82.1 ± 2.7%) and stable biofilm structure were achieved.},
}
@article {pmid31366707,
year = {2019},
author = {Brown, JR and Jurcisek, J and Lakhani, V and Snedden, A and Ray, WC and Mokrzan, EM and Bakaletz, LO and Das, J},
title = {In Silico Modeling of Biofilm Formation by Nontypeable Haemophilus influenzae In Vivo.},
journal = {mSphere},
volume = {4},
number = {4},
pages = {},
doi = {10.1128/mSphere.00254-19},
pmid = {31366707},
issn = {2379-5042},
support = {R01 DC003915/NIDCD NIH HHS/National Institute on Deafness and Other Communication Disorders/United States ; R01 GM103612/NIGMS NIH HHS/National Institute of General Medical Sciences/United States ; },
abstract = {Biofilms formed by nontypeable Haemophilus influenzae (NTHI) bacteria play an important role in multiple respiratory tract diseases. Visual inspection of the morphology of biofilms formed during chronic infections shows distinct differences from biofilms formed in vitro To better understand these differences, we analyzed images of NTHI biofilms formed in the middle ears of Chinchilla lanigera and developed an in silico agent-based model of the formation of NTHI biofilms in vivo We found that, as in vitro, NTHI bacteria are organized in self-similar patterns; however, the sizes of NTHI clusters in vivo are more than 10-fold smaller than their in vitro counterparts. The agent-based model reproduced these patterns and suggested that smaller clusters occur due to elimination of planktonic NTHI cells by the host responses. Estimation of model parameters by fitting simulation results to imaging data showed that the effects of several processes in the model change during the course of the infection.IMPORTANCE Multiple respiratory illnesses are associated with formation of biofilms within the human airway by NTHI. However, a substantial amount of our understanding of the mechanisms that underlie NTHI biofilm formation is obtained from in vitro studies. Our in silico model that describes biofilm formation by NTHI within the middle ears of Chinchilla lanigera will help isolate processes potentially responsible for the differences between the morphologies of biofilms formed in vivo versus those formed in vitro Thus, the in silico model can be used to glean mechanisms that underlie biofilm formation in vivo and connect those mechanisms to those obtained from in vitro experiments. The in silico model developed here can be extended to investigate potential roles of specific host responses (e.g., mucociliary clearance) on NTHI biofilm formation in vivo The developed computational tools can also be used to analyze and describe biofilm formation by other bacterial species in vivo.},
}
@article {pmid31366705,
year = {2019},
author = {Kean, R and Ramage, G},
title = {Combined Antifungal Resistance and Biofilm Tolerance: the Global Threat of Candida auris.},
journal = {mSphere},
volume = {4},
number = {4},
pages = {},
doi = {10.1128/mSphere.00458-19},
pmid = {31366705},
issn = {2379-5042},
abstract = {The enigmatic yeast Candida auris has emerged over the last decade and rapidly penetrated our consciousness. The global threat from this multidrug-resistant yeast has generated a call to arms from within the medical mycology community. Over the past decade, our understanding of how this yeast has spread globally, its clinical importance, and how it tolerates and resists antifungal agents has expanded. This review highlights the clinical importance of antifungal resistance in C. auris and explores our current understanding of the mechanisms associated with azole, polyene, and echinocandin resistance. We also discuss the impact of phenotypic tolerance, with particular emphasis on biofilm-mediated resistance, and present new pipelines of antifungal drugs that promise new hope in the management of C. auris infection.},
}
@article {pmid31366076,
year = {2019},
author = {Ghensi, P and Bettio, E and Maniglio, D and Bonomi, E and Piccoli, F and Gross, S and Caciagli, P and Segata, N and Nollo, G and Tessarolo, F},
title = {Dental Implants with Anti-Biofilm Properties: A Pilot Study for Developing a New Sericin-Based Coating.},
journal = {Materials (Basel, Switzerland)},
volume = {12},
number = {15},
pages = {},
doi = {10.3390/ma12152429},
pmid = {31366076},
issn = {1996-1944},
support = {Prot. 24/2015//SIdP (Italian Society of Periodontology and Implantology)/ ; },
abstract = {AIM: several strategies have been tested in recent years to prevent bacterial colonization of dental implants. Sericin, one of the two main silk proteins, possesses relevant biological activities and also literature reports about its potential antibacterial properties, but results are discordant and not yet definitive. The aim of this study was to evaluate the effectiveness of different experimental protocols in order to obtain a sericin-based coating on medical grade titanium (Ti) able to reduce microbial adhesion to the dental implant surface.<br><br>MATERIALS AND METHODS: different strategies for covalent bonding of sericin to Ti were pursued throughout a multi-step procedure on Ti-6Al-4V disks. The surface of grade 5 Ti was initially immersed in NaOH solution to obtain the exposure of functional -OH groups. Two different silanization strategies were then tested using aminopropyltriethoxysilane (APTES). Eventually, the bonding between silanized Ti-6Al-4V and sericin was obtained with two different crosslinking processes: glutaraldehyde (GLU) or carbodiimide/N-Hydroxy-succinimide (EDC/NHS). Micro-morphological and compositional analyses were performed on the samples at each intermediate step to assess the most effective coating strategy able to optimize the silanization and bioconjugation processes. Microbiological tests on the coated Ti-6Al-4V disks were conducted in vitro using a standard biofilm producer strain of Staphylococcus aureus (ATCC 6538) to quantify the inhibition of microbial biofilm formation (anti-biofilm efficacy) at 24 hours.<br><br>RESULTS: both silanization techniques resulted in a significant increase of silicon (Si) on the Ti-6Al-4V surfaces etched with NaOH. Differences were found between GLU and EDC/NHS bioconjugation strategies in terms of composition, surface micro-morphology and anti-biofilm efficacy. Ti-6Al-4V samples coated with GLU-bound sericin after silanization obtained via vapor phase deposition proved that this technique is the most convenient and effective coating strategy, resulting in a bacterial inhibition of about 53% in respect to the uncoated Ti-6Al-4V disks.<br><br>CONCLUSIONS: The coating with glutaraldehyde-bound sericin after silanization in the vapor phase showed promising bacterial inhibition values with a significant reduction of S. aureus biofilm. Further studies including higher number of replicates and more peri-implant-relevant microorganisms are needed to evaluate the applicability of this experimental protocol to dental implants.},
}
@article {pmid31364079,
year = {2019},
author = {Lora-Tamayo, J and Murillo, O and Ariza, J},
title = {Clinical Use of Colistin in Biofilm-Associated Infections.},
journal = {Advances in experimental medicine and biology},
volume = {1145},
number = {},
pages = {181-195},
doi = {10.1007/978-3-030-16373-0_13},
pmid = {31364079},
issn = {0065-2598},
abstract = {Biofilm is an adaptive bacterial strategy whereby microorganisms become encased in a complex glycoproteic matrix. The low concentration of oxygen and nutrients in this environment leads to heterogeneous phenotypic changes in the bacteria, with antimicrobial tolerance being of paramount importance. As with other antibiotics, the activity of colistin is impaired by biofilm-embedded bacteria. Therefore, the recommendation for administering high doses in combination with a second drug, indicated for planktonic infections, remains valid in this setting. Notably, colistin has activity against metabolically inactive biofilm-embedded cells located in the inner layers of the biofilm structure. This is opposite and complementary to the activity of other antimicrobials that are able to kill metabolically active cells in the outer layers of the biofilm. Several experimental models have shown a higher activity of colistin when used in combination with other agents, and have reported that this can avoid the emergence of colistin-resistant subpopulations. Most experience of colistin in biofilm-associated infections comes from patients with cystic fibrosis, where the use of nebulized colistin allows high concentrations to reach the site of the infection. However, limited clinical experience is available in other scenarios, such as osteoarticular infections or device-related central nervous system infections caused by multi-drug resistant microorganisms. In the latter scenario, the use of intraventricular or intrathecal colistin also permits high local concentrations and good clinical results. Overall, the efficacy of intravenous colistin seems to be poor, but its association with a second antimicrobial significantly increases the response rate. Given its activity against inner bioflm-embedded cells, its possible role in combination with other antibiotics, beyond last-line therapy situations, should be further explored.},
}
@article {pmid31363870,
year = {2019},
author = {Piotrowski, M and Wultańska, D and Obuch-Woszczatyński, P and Pituch, H},
title = {Fructooligosaccharides and mannose affect Clostridium difficile adhesion and biofilm formation in a concentration-dependent manner.},
journal = {European journal of clinical microbiology &amp; infectious diseases : official publication of the European Society of Clinical Microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10096-019-03635-7},
pmid = {31363870},
issn = {1435-4373},
support = {UMO:2017/25/N/NZ6/01763//Narodowe Centrum Nauki/ ; },
abstract = {The aim of this study was to investigate the effects that prebiotic and candidates for prebiotics on Clostridium difficile strains to adhere to various human epithelial cell lines and to compare the adhesive properties of specific C. difficile strains. We also sought to examine the effect of different concentrations of fructooligosaccharides and mannose on the formation of biofilms by C. difficile strains. The influence of cellobiose, fructooligosaccharides, inulin, mannose, and raffinose on the adherence properties of various C. difficile strains, including motile 630, non-motile M120, and 10 clinical motile ribotype 027 strains, to non-mucous secreting HT-29, mucous secreting HT-29 MXT, and CCD 841 CoN cells lines. The most effective prebiotics were used in biofilm formation assays. We demonstrated that all C. difficile strains adhered to all cell lines. However, the C. difficile M120 non-motile strain was statistically more likely to adhere to all three cell lines (CFU median, 40) compared to the motile strains (CFU median, 3; p < 0.001). Furthermore, among the carbohydrates examined, only fructooligosaccharides and mannose were found to significantly decrease adhesion (p < 0.001) of C. difficile strains. Alternatively, using a biofilm assay, we observed, via confocal laser scanning microscopy, that sub-inhibitory concentrations (1%) of fructooligosaccharides and mannose functioned to increase biofilm formation by C. difficile. We demonstrated that specific prebiotics and candidate prebiotics exhibit varying anti-adhesive properties towards C. difficile in vitro and that treatment with sub-inhibitory concentrations of prebiotics can cause an increase in biofilm formation by C. difficile.},
}
@article {pmid31363032,
year = {2019},
author = {Orazi, G and Ruoff, KL and O'Toole, GA},
title = {Pseudomonas aeruginosa Increases the Sensitivity of Biofilm-Grown Staphylococcus aureus to Membrane-Targeting Antiseptics and Antibiotics.},
journal = {mBio},
volume = {10},
number = {4},
pages = {},
doi = {10.1128/mBio.01501-19},
pmid = {31363032},
issn = {2150-7511},
support = {R37 AI083256/NIAID NIH HHS/National Institute of Allergy and Infectious Diseases Extramural Activities/United States ; T32 AI007519/NIAID NIH HHS/National Institute of Allergy and Infectious Diseases Extramural Activities/United States ; },
abstract = {Pseudomonas aeruginosa and Staphylococcus aureus often cause chronic, recalcitrant infections in large part due to their ability to form biofilms. The biofilm mode of growth enables these organisms to withstand antibacterial insults that would effectively eliminate their planktonic counterparts. We found that P. aeruginosa supernatant increased the sensitivity of S. aureus biofilms to multiple antimicrobial compounds, including fluoroquinolones and membrane-targeting antibacterial agents, including the antiseptic chloroxylenol. Treatment of S. aureus with the antiseptic chloroxylenol alone did not decrease biofilm cell viability; however, the combination of chloroxylenol and P. aeruginosa supernatant led to a 4-log reduction in S. aureus biofilm viability compared to exposure to chloroxylenol alone. We found that the P. aeruginosa-produced small molecule 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO) is responsible for the observed heightened sensitivity of S. aureus to chloroxylenol. Similarly, HQNO increased the susceptibility of S. aureus biofilms to other compounds, including both traditional and nontraditional antibiotics, which permeabilize bacterial membranes. Genetic and phenotypic studies support a model whereby HQNO causes an increase in S. aureus membrane fluidity, thereby improving the efficacy of membrane-targeting antiseptics and antibiotics. Importantly, our data show that P. aeruginosa exoproducts can enhance the ability of various antimicrobial agents to kill biofilm populations of S. aureus that are typically difficult to eradicate. Finally, our discovery that altering membrane fluidity shifts antimicrobial sensitivity profiles of bacterial biofilms may guide new approaches to target persistent infections, such as those commonly found in respiratory tract infections and in chronic wounds.IMPORTANCE The thick mucus in the airways of cystic fibrosis (CF) patients predisposes them to frequent, polymicrobial respiratory infections. Pseudomonas aeruginosa and Staphylococcus aureus are frequently coisolated from the airways of individuals with CF, as well as from diabetic foot ulcers and other wounds. Both organisms form biofilms, which are notoriously difficult to eradicate and promote chronic infection. In this study, we have shown that P. aeruginosa-secreted factors can increase the efficacy of compounds that alone have little or no bactericidal activity against S. aureus biofilms. In particular, we discovered that P. aeruginosa exoproducts can potentiate the antistaphylococcal activity of phenol-based antiseptics and other membrane-active drugs. Our findings illustrate that polymicrobial interactions can dramatically increase antibacterial efficacy in vitro and suggest that altering membrane physiology promotes the ability of certain drugs to kill bacterial biofilms-knowledge that may provide a path for the discovery of new biofilm-targeting antimicrobial strategies.},
}
@article {pmid31362660,
year = {2019},
author = {Jain, N and Mansuri, A},
title = {Stopping the Unstoppable: Unconventional methods to prevent biofilm growth.},
journal = {Current drug discovery technologies},
volume = {},
number = {},
pages = {},
doi = {10.2174/1570163816666190726153441},
pmid = {31362660},
issn = {1875-6220},
abstract = {Biofilms are consortia of microorganisms encased in extracellular matrix that protect cells from adverse conditions. A biofilm matrix is typically composed of extracellular DNA, cellulose and proteinaceous amyloid fibers. The matrix aids in adhesion to abiotic and biotic surface including medical devices and host tissues. Presence of biofilm makes bacteria more resilient and non-responsive to most current treatment regimes at disposal. Therefore, biofilm-associated infections are serious threat in hospital settings and pose a huge burden on economy. Inhibition of matrix components (cellulose and/or amyloid formation) has emerged as a lucrative alternative strategy to cure biofilm-related infections and combat antibiotic resistance. Here we review the current and emerging therapeutic interventions to mitigate persistent infections due to biofilms. The successful implementation of these interventions will have a huge impact on alleviating the current financial burden on healthcare services.},
}
@article {pmid31362602,
year = {2019},
author = {Hirayama, S and Nojima, N and Furukawa, S and Ogihara, H and Morinaga, Y},
title = {Steric microstructure of mixed-species biofilm formed by interaction between Lactobacillus plantarum ML11-11 and Saccharomyces cerevisiae.},
journal = {Bioscience, biotechnology, and biochemistry},
volume = {},
number = {},
pages = {1-4},
doi = {10.1080/09168451.2019.1649978},
pmid = {31362602},
issn = {1347-6947},
abstract = {The mixed-species biofilm of Lactobacillus plantarum ML11-11 (LAB) and yeast had a double-layered structure with the ground layer composed of LAB cells, and the upper layer composed of coaggregates of LAB and yeast cells. The ability of LAB to adhere to both, the solid surface and the yeast cells, enabled the formation and maintenance of the biofilm as an ecosystem for LAB and yeast.},
}
@article {pmid31362224,
year = {2019},
author = {Ashkanani, A and Almomani, F and Khraisheh, M and Bhosale, R and Tawalbeh, M and AlJaml, K},
title = {Bio-carrier and operating temperature effect on ammonia removal from secondary wastewater effluents using moving bed biofilm reactor (MBBR).},
journal = {The Science of the total environment},
volume = {693},
number = {},
pages = {133425},
doi = {10.1016/j.scitotenv.2019.07.231},
pmid = {31362224},
issn = {1879-1026},
abstract = {This study investigates the impact of bio-carriers' surface area and shape, wastewater chemistry and operating temperature on ammonia removal from real wastewater effluents using Moving bed biofilm reactors (MBBRs) operated with three different AnoxKaldness bio-carriers (K3, K5, and M). The study concludes the surface area loading rate, specific surface area, and shape of bio-carrier affect ammonia removal under real conditions. MBBR kinetics and sensitivity for temperature changes were affected by bio-carrier type. High surface area bio-carriers resulted in low ammonia removal and bio-carrier clogging. Significant ammonia removals of 1.420 ± 0.06 and 1.103 ± 0.06 g - N/m2. d were achieved by K3(As = 500 m2/m3) at 35 and 20 °C, respectively. Lower removals were obtained by high surface area bio-carrier K5 (1.123 ± 0.06 and 0.920 ± 0.06 g - N/m2. d) and M (0.456 ± 0.05 and 0.295 ± 0.05 g - N/m2. d) at 35 and 20 °C, respectively. Theta model successfully represents ammonia removal kinetics with θ values of 1.12, 1.06 and 1.13 for bio-carrier K3, K5 and M respectively. MBBR technology is a feasible choice for treatment of real wastewater effluents containing high ammonia concentrations.},
}
@article {pmid31362109,
year = {2019},
author = {Sayar, F and Chiniforush, N and Bahador, A and Etemadi, A and Akhondi, N and Azimi, C},
title = {Efficacy of antimicrobial photodynamic therapy for elimination of Aggregatibacter actinomycetemcomitans biofilm on Laser-Lok titanium discs.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {27},
number = {},
pages = {462-466},
doi = {10.1016/j.pdpdt.2019.07.012},
pmid = {31362109},
issn = {1873-1597},
abstract = {BACKGROUND: Antimicrobial Photodynamic therapy (aPDT) is a novel modality suggested for treatment of peri-implantitis. This study aimed to assess the effect of aPDT with toluidine blue (TBO) and indocyanine green (ICG) and 635 nm and 808 nm diode laser on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) biofilm formed on Laser-Lok titanium discs.<br><br>MATERIALS AND METHODS: Eighty sterile Laser-Lok titanium discs were inoculated with A. actinomycetemcomitans to form biofilm and were randomly divided into 8 groups (n = 10) of control, chlorhexidine (CHX), TBO, ICG, 635 nm diode laser with 220 mW power, 808 nm diode laser with 250 mW power, 100 μg/mL TBO+635 nm diode laser and ICG+808 nm diode laser. Number of colony forming units (CFUs) on the surface of each disc was counted after the intervention. Data were analyzed using the Kruskal-Wallis test.<br><br>RESULTS: Significant differences were noted in colony count among the eight groups after the intervention (P = 0.001). Pairwise comparisons with adjusted P value test showed that aPDT with TBO+635 nm laser and ICG+808 nm laser caused significant reduction of bacterial biofilm compared to the control group (P = 0.0001). TBO alone caused significant reduction of biofilm compared to the control group (P = 0.004). No other significant differences were noted (P > 0.05).<br><br>CONCLUSION: Within the limitations of this study, the results showed that aPDT is a potential modality for decontamination of implant surface and reduction of A. actinomycetemcomitans biofilm in vitro. In this study, aPDT with TBO+635 nm diode laser and ICG+808 nm diode laser decreased the bacterial load on titanium discs.},
}
@article {pmid31360725,
year = {2019},
author = {Leonhard, M and Zatorska, B and Moser, D and Schneider-Stickler, B},
title = {Growth Media for Mixed Multispecies Oropharyngeal Biofilm Compositions on Silicone.},
journal = {BioMed research international},
volume = {2019},
number = {},
pages = {8051270},
doi = {10.1155/2019/8051270},
pmid = {31360725},
issn = {2314-6141},
abstract = {Aims: Microbial colonization of silicone voice prostheses by bacteria and Candida species limits the device lifetime of modern voice prostheses in laryngectomized patients. Thus, research focuses on biofilm inhibitive properties of novel materials, coatings, and surface enhancements. Goal of this in vitro study was the evaluation of seven commonly used growth media to simulate growth of mixed oropharyngeal species as mesoscale biofilms on prosthetic silicone for future research purposes.<br><br>Methods and Results: Yeast Peptone Dextrose medium (YPD), Yeast Nitrogen Base medium (YNB), M199 medium, Spider medium, RPMI 1640 medium, Tryptic Soy Broth (TSB), and Fetal Bovine Serum (FBS) were used to culture combined mixed Candida strains and mixed bacterial-fungal compositions on silicone over the period of 22 days. The biofilm surface spread and the microscopic growth showed variations from in vivo biofilms depending on the microbial composition and growth medium.<br><br>Conclusion: YPD and FBS prove to support continuous in vitro growth of mixed bacterial-fungal oropharyngeal biofilms deposits over weeks as needed for longterm in vitro testing with oropharyngeal biofilm compositions.<br><br>The study provides data on culture conditions for mixed multispecies biofilm compositions that can be used for future prosthesis designs.},
}
@article {pmid31357945,
year = {2019},
author = {Ramos, JN and Souza, C and Faria, YV and da Silva, EC and Veras, JFC and Baio, PVP and Seabra, SH and de Oliveira Moreira, L and Hirata Júnior, R and Mattos-Guaraldi, AL and Vieira, VV},
title = {Bloodstream and catheter-related infections due to different clones of multidrug-resistant and biofilm producer Corynebacterium striatum.},
journal = {BMC infectious diseases},
volume = {19},
number = {1},
pages = {672},
doi = {10.1186/s12879-019-4294-7},
pmid = {31357945},
issn = {1471-2334},
abstract = {BACKGROUND: Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen associated with immunocompromised and chronically ill patients, as well as nosocomial outbreaks. In this study, we characterized 23 MDR C. striatum isolated of bloodstream and catheter-related infections from a hospital of Rio de Janeiro.<br><br>METHODS: C. striatum isolates were identified by 16S rRNA and rpoB genes sequencing. The dissemination of these isolates was accomplished by pulsed-field gel electrophoresis (PFGE). All isolates were submitted to antimicrobial susceptibility testing by disk diffusion and by minimum inhibitory concentration using E-test strips methods. Antimicrobial resistance genes were detected by polymerase chain reaction. Quantitative tests were performed on four different abiotic surfaces and the ability to produce biofilm on the surface of polyurethane and silicone catheter was also demonstrated by scanning electron microscopy.<br><br>RESULTS: Eleven PFGE profiles were found. The PFGE profile I was the most frequently observed among isolates. Five different MDR profiles were found and all PFGE profile I isolates presented susceptibility only to tetracycline, vancomycin, linezolid and daptomycin. Only the multidrug-susceptible isolate did not show mutations in the quinolone-resistance determinant region (QRDR) of the gyrA gene and was negative in the search of genes encoding antibiotic resistance. The other 22 isolates were positive to resistance genes to aminoglycoside, macrolides/lincosamides and chloramphenicol and showed mutations in the QRDR of the gyrA gene. Scanning electron microscopy illustrated the ability of MDR blood isolate partaker of the epidemic clone (PFGE profile I) to produce mature biofilm on the surface of polyurethane and silicone catheter.<br><br>CONCLUSIONS: Genotyping analysis by PFGE revealed the permanence of the MDR PFGE profile I in the nosocomial environment. Other new PFGE profiles emerged as etiologic agents of invasive infections. However, the MDR PFGE profile I was also found predominant among patients with hematogenic infections. The high level of multidrug resistance associated with biofilm formation capacity observed in MDR C. striatum is a case of concern.},
}
@article {pmid31357240,
year = {2019},
author = {Feng, G and Cheng, Y and Worobo, RW and Borca-Tasciuc, DA and Moraru, CI},
title = {Nanoporous anodic alumina reduces Staphylococcus biofilm formation.},
journal = {Letters in applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/lam.13201},
pmid = {31357240},
issn = {1472-765X},
abstract = {Staphylococcus epidermidis and Staphylococcus aureus, two bacterial strains commonly associated with biofilm-related medical infections and food poisoning, can rapidly colonize biotic and abiotic surfaces. The present study investigates the ability of anodic alumina surfaces with nanoporous surface topography to minimize the attachment and biofilm formation mediated by these pathogenic bacterial strains. Early attachment and subsequent biofilm development were retarded on surfaces with nanopores of 15-25 nm in diameter compared to surfaces with 50-100 nm pore diameter and nanosmooth surfaces. After 30 min of incubation in nutritive media, the biomass accumulation per unit surface area was 2·93 ± 1·72 μm3 μm-2 for the 15 nm, 3·49 ± 1·97 μm3 μm-2 for the 25 nm, as compared to 14·04 ± 6·39 μm3 μm-2 for the nanosmooth, 11·88 ± 9·72 μm3 μm-2 for the 50 nm, and 12·09 ± 11·84 μm3 μm-2 for the 100 nm surfaces, respectively. These findings suggest that anodic alumina with small size nanoscale pores could reduce the incidence of staphylococcal biofilms and infections, and shows promise as a material for a variety of medical applications and food contact surfaces. This article is protected by copyright. All rights reserved.},
}
@article {pmid31356873,
year = {2019},
author = {Lee, HH and Del Pozzo, J and Salamanca, SA and Hernandez, H and Martinez, LR},
title = {Reduced phagocytosis and killing of Cryptococcus neoformans biofilm-derived cells by J774.16 macrophages is associated with fungal capsular production and surface modification.},
journal = {Fungal genetics and biology : FG &amp; B},
volume = {132},
number = {},
pages = {103258},
doi = {10.1016/j.fgb.2019.103258},
pmid = {31356873},
issn = {1096-0937},
support = {R01 AI145559/AI/NIAID NIH HHS/United States ; },
abstract = {Cryptococcus neoformans is an opportunistic encapsulated pathogen that causes life-threatening meningoencephalitis in individuals with immunosuppression. We compared the interactions of C. neoformans planktonic and biofilm-derived cells with J774.16 macrophage-like cells. Planktonic cells are more phagocytized and killed by J774.16 cells than biofilm-derived fungal cells. Biofilm-derived cryptococci possess larger capsule size and release significantly more capsular polysaccharide than planktonic cells in culture. Biofilm-derived fungi exhibited upregulation of genes involved in capsular production. Capsular-specific monoclonal antibody 18B7 demonstrated differential binding to the surface of planktonic and biofilm-derived cryptococci providing a plausible strategy for fungal evasion of macrophages and persistence. Future studies are necessary to elucidate how C. neoformans biofilm-derived cells regulate their virulence factors when interacting with cells of the immune system.},
}
@article {pmid31355999,
year = {2019},
author = {Chuang, PJ and Swaminathan, V and Pavlovsky, L and Marquez-Catral, L and Jones, DL and Song, L},
title = {Negative influence of biofilm on CoCrMo corrosion.},
journal = {Journal of biomedical materials research. Part A},
volume = {107},
number = {11},
pages = {2556-2566},
doi = {10.1002/jbm.a.36761},
pmid = {31355999},
issn = {1552-4965},
abstract = {Minimal studies exist investigating biofilm-induced corrosion of orthopaedic implants. This study investigates potential contributions of Pseudomonas aeruginosa and Staphylococcus aureus biofilms on corrosion resistance of CoCrMo under static and fretting conditions. Biofilms were cultured on CoCrMo coupons for either 4 weeks (static culture) or 6 days (fretting culture; pin-on-disk with a Ti6Al4V hemispherical tip pin). Morphology of biofilms and corrosion of coupon surfaces were analyzed via SEM. Open circuit potential and electrochemical impedance spectroscopy measurements were collected for corrosion performance evaluation. Results showed no visible corrosion on coupon surfaces in static culture, which suggests these biofilms alone do not induce severe corrosion under the conditions of this study. However, electrochemical data showed biofilm presence lowered coupon electrochemical impedance in static and fretting cultures, suggesting resistive and capacitive characteristics of the metal oxide-biofilm-media interface were altered. Under fretting, the P. aeruginosa group exhibited a distinct damage morphology and Co:Cr:Mo ratio within the wear scar when compared with S. aureus and the bacteria-free control. These differences suggest the presence of P. aeruginosa biofilms may negatively impact corrosion resistance at the fretting interface. Taken together these results demonstrate biofilms can contribute to implant corrosion by influencing the electrochemical impedance of implant metal surfaces.},
}
@article {pmid31354823,
year = {2019},
author = {Cunha, EJ and Auersvald, CM and Deliberador, TM and Gonzaga, CC and Esteban Florez, FL and Correr, GM and Storrer, CLM},
title = {Effects of Active Oxygen Toothpaste in Supragingival Biofilm Reduction: A Randomized Controlled Clinical Trial.},
journal = {International journal of dentistry},
volume = {2019},
number = {},
pages = {3938214},
doi = {10.1155/2019/3938214},
pmid = {31354823},
issn = {1687-8728},
abstract = {Gingivitis is still considered a major risk factor for the occurrence and progression of periodontal disease. The aim of the present study was to compare the long-term (1, 12, and 18 weeks) antiplaque and antigingivitis efficacies of two commercially available toothpastes, Colgate Total® (CT) and BlueM® (BM), against attached supragingival dental plaque and gingival inflammation in an experimental gingivitis model. A parallel double-blinded randomized clinical trial including 39 dental students who refrained from all plaque control methods (manual or chemical) for 7 days was conducted. After the establishment of clinical gingivitis, participants were randomized into two experimental groups (CT and BM). Plaque index (PI) and gingival index (GI) were then calculated according to Turesky's modified Quigley and Hein index. Participants were assessed in four time periods (preclinical trial phase (W -1), gingivitis phase (W0), one week (W1), twelve weeks (W12), and eighteen weeks (W18)). Participants' stimulated saliva was collected and cultured (either aerobically or anaerobically, 37°C, 48 hours) in each time period (W -1, W0, W1, W12, and W18) for the count of viable colonies. Obtained data were analyzed using 2-way ANOVA and Tukey's test (α = 0.05). No significant differences were found (p > 0.05) between experimental groups at W -1. Significant differences between groups were observed at W0 (p < 0.05) for the parameter time period, but not for the interaction between parameters (time period ∗ toothpastes). Lower bacterial counts were observed in both groups after one week of toothbrushing; however, no significant differences were found between investigated dentifrices. Intra- and intergroup comparisons revealed that significant differences were not found (p > 0.05) between dentifrices at W1, W12, and W18 for both GI and PI. The present study demonstrated that toothpastes containing active oxygen and lactoferrin (BM) have comparable antiplaque and antigingivitis efficacies with triclosan-containing toothpastes (CT).},
}
@article {pmid31354319,
year = {2019},
author = {Abd El-Baky, RM and Sandle, T and John, J and Abuo-Rahma, GEA and Hetta, HF},
title = {A novel mechanism of action of ketoconazole: inhibition of the NorA efflux pump system and biofilm formation in multidrug-resistant Staphylococcus aureus.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {1703-1718},
doi = {10.2147/IDR.S201124},
pmid = {31354319},
issn = {1178-6973},
abstract = {Background: The rapid emergence of antimicrobial resistance among Gram-positive organisms, especially staphylococci, has become a serious clinical challenge. Efflux machinery and biofilm formation are considered two of the main causes of antimicrobial resistance and therapy failure. Aim: Our study aims to evaluate the antibiofilm and efflux pump inhibitory activity of the antifungal ketoconazole against multidrug-resistant (MDR) Staphylococcus aureus. Methods: Ketoconazole was tested for its effect on the following: minimum inhibitory concentrations (MICs) of ciprofloxacin, norfloxacin, levofloxacin, and ethidium bromide (EtBr) by the broth microdilution method, the efflux of EtBr by NorA-positive MDR S. aureus, and the relative expression of NorA, NorB, and NorC efflux pump genes. Docking studies of ketoconazole were performed using 1PW4 (glycerol-3-phosphate transporter from Escherichia coli which was the representative structure from the major facilitator superfamily). Results: Ketoconazole significantly decreased the MICs of levofloxacin, ciprofloxacin, norfloxacin, and EtBr (a substrate for efflux pump) by 8 to 1024-fold (P<0.01) and decreased the efflux of EtBr. Furthermore, a time-kill assay revealed that combinations of levofloxacin with ketoconazole or carbonyl cyanide m-chlorophenylhydrazone showed no growth for the tested strains after 24 h in comparison to the effect of levofloxacin alone. Docking studies and the ability of ketoconazole to diminish the relative expression of NorA gene in comparison to control (untreated strains) confirmed its action as an efflux pump inhibitor. Conclusion: The findings showed that the antifungal ketoconazole has no antibacterial activity but can potentiate the activity of the fluroquinolones against MDR S. aureus via inhibiting efflux pump and biofilm formation in vitro.},
}
@article {pmid31352165,
year = {2019},
author = {Riegler, P and Bieringer, E and Chrusciel, T and Stärz, M and Löwe, H and Weuster-Botz, D},
title = {Continuous conversion of CO2/H2 with Clostridium aceticum in biofilm reactors.},
journal = {Bioresource technology},
volume = {291},
number = {},
pages = {121760},
doi = {10.1016/j.biortech.2019.121760},
pmid = {31352165},
issn = {1873-2976},
mesh = {Acetic Acid/metabolism ; *Biofilms ; *Bioreactors ; Carbon Dioxide/*metabolism ; Clostridium/*physiology ; Fermentation ; Hydrogen/*metabolism ; },
abstract = {A lab-scale stirred-tank bioreactor was reversibly retrofitted to a packed-bed and a trickle-bed biofilm reactor to study and compare the conversion of CO2/H2 with immobilised Clostridiumaceticum. The biofilm reactors were characterised and their functionality confirmed. Up to 8.6 g of C. aceticum were immobilised onto 300 g sintered ceramic carrier material, proving biofilm formation to be a robust means for cell retention of C. aceticum. Continuous CO2/H2-fermentation studies were performed with both biofilm reactor configurations as function of dilution rates, partial gas pressures and gas flow rates. The experiments showed that in the packed-bed biofilm reactor, the acetate space-time yield was independent of the dilution rate, because of low H2 gas-liquid mass transfer rates (≤17 mmol H2 L-1 h-1). The continuous operation of the trickle-bed biofilm reactor increased the gas-liquid mass transfer rates to up to 56 mmol H2 L-1 h-1. Consequently, the acetate space-time yield of up to 14 mmol acetate L-1 h-1 was improved 3-fold at hydrogen conversions of up to 96%.},
}
@article {pmid31351106,
year = {2019},
author = {Bautista-Hernández, LA and Gómez-Olivares, JL and Buentello-Volante, B and Dominguez-Lopez, A and Garfias, Y and Acosta-García, MC and Calvillo-Medina, RP and Bautista-de Lucio, VM},
title = {Negative interaction of Staphylococcus aureus on Fusarium falciforme growth ocular isolates in an in vitro mixed biofilm.},
journal = {Microbial pathogenesis},
volume = {135},
number = {},
pages = {103644},
doi = {10.1016/j.micpath.2019.103644},
pmid = {31351106},
issn = {1096-1208},
abstract = {The interactions between prokaryotes and eukaryotes are abundant in nature. These microorganisms also interact in the human body. Fungal-bacteria interactions are present in many diseases. In this study, we evaluated the microbial interaction of Fusarium falciforme and Staphylococcus aureus developing mixed biofilm in vitro. When both microorganisms grew up together the mixed biofilm biomass decreased than F. falciforme monobiofilm biomass. S. aureus was able to interact and form aggregates over the mycelium and conidia surface of F. falciforme. Our results suggest that S. aureus could bind to colloidal chitin. On another hand, the supernatants from S. aureus biofilm and S. aureus-F. falciforme presented an antifungal effect over F. falciforme biofilm formation. Finally we found that the pH had an inhibitory effect over fungal biofilm formation. We concluded that S. aureus can affect the F. falciforme growth negatively in mixed biofilm involving factors like pH, supernatants compounds, anchor to chitin, and bacterial viability.},
}
@article {pmid31350606,
year = {2019},
author = {Schopf, A and Delatolla, R and Kirkwood, KM},
title = {Partial nitritation at elevated loading rates: design curves and biofilm characteristics.},
journal = {Bioprocess and biosystems engineering},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00449-019-02177-8},
pmid = {31350606},
issn = {1615-7605},
support = {497995-2017//Natural Sciences and Engineering Research Council of Canada/ ; },
abstract = {There is a need to develop low operational intensity, cost-effective, and small-footprint systems to treat wastewater. Partial nitritation has been studied using a variety of control strategies, however, a gap in passive operation is evident. This research investigates the use of elevated loading rates as a strategy for achieving low operational intensity partial nitritation in a moving bed biofilm reactor (MBBR) system. The effects of loading rates on nitrification kinetics and biofilm characteristics were determined at elevated, steady dissolved oxygen concentrations between 5.5 and 7.0 mg O2/L and ambient temperatures between 19 and 21 °C. Four elevated loading rates (3, 4, 5 and 6.5 g NH4+-N/m2 days) were tested with a distinct shift in kinetics being observed towards nitritation at elevated loadings. Complete partial nitritation (100% nitrite production) was achieved at 6.5 g NH4+-N/m2 days, likely due to thick biofilm (572 µm) and elevated NH4+-N load, which resulted in suppression of nitrite oxidation.},
}
@article {pmid31349525,
year = {2019},
author = {Ismail, NA and Amin, KAM and Majid, FAA and Razali, MH},
title = {Gellan gum incorporating titanium dioxide nanoparticles biofilm as wound dressing: Physicochemical, mechanical, antibacterial properties and wound healing studies.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {103},
number = {},
pages = {109770},
doi = {10.1016/j.msec.2019.109770},
pmid = {31349525},
issn = {1873-0191},
abstract = {In this work, the potential of titanium dioxide nanoparticles incorporated gellan gum (GG + TiO2-NPs) biofilm as wound dressing material was investigated. The GG + TiO2-NPs biofilm was prepared via evaporative casting technique and was characterized using FTIR, XRD, and SEM to study their physiochemical properties. The mechanical properties, swelling and water vapor transmission rate (WVTR) of biofilm was determined to comply with an ideal wound dressing material. In vitro and in vivo wound healing studies was carried out to evaluate the performance of GG + TiO2-NPs biofilm. In vitro wound healing was studied on 3 T3 mouse fibroblast cells for cell viability, cell proliferation, and scratch assay. The acridine orange/propidium iodide (AO/PI) staining and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were used to evaluate the viability of cell and cell proliferation. Cell migration assay was analyzed using Essen BioScience IncuCyteTM Zoom system. In vivo wound healing via open excision wounds model on Sprague Dawley rat was studied within 14 days. The FT-IR spectra of GG + TiO2-NPs biofilm show main bands assigned to OH stretching, OH deformation, and TiO stretching modes. XRD pattern of GG + TiO2-NPs biofilm suggesting that TiO2-NPs was successfully incorporated in biofilm and well distributed on the surface as proved by SEM analysis. The GG + TiO2-NPs biofilm shows higher mechanical strength and swelling (3.76 ± 0.11 MPa and 1061 ± 6%) as compared to pure GG film (3.32 ± 0.08 Mpa and 902 ± 6%), respectively. GG + TiO2-NPs biofilm shows good antibacterial properties as 9 ± 0.25 mm and 11 ± 0.06 mm exhibition zone was observed against Staphylococcus aureus and Escherichia coli bacteria, respectively. While no exhibition zone was obtained for pure GG biofilm. GG + TiO2-NPs biofilm also demonstrated better cell-to-cell interaction properties, as it's promoted cell proliferation and cell migration to accelerate open excision wound healing on Sprague Dawley rat. The wound treated with GG + TiO2-NPs biofilm was healed within 14 days, on the other hand, the wound is still can be seen when it was treated with GG. However, GG and GG + TiO2-NPs biofilm show no cytotoxicity effects on mouse fibroblast cells.},
}
@article {pmid31349520,
year = {2019},
author = {Vögeling, H and Plenagl, N and Seitz, BS and Duse, L and Pinnapireddy, SR and Dayyoub, E and Jedelska, J and Brüßler, J and Bakowsky, U},
title = {Synergistic effects of ultrasound and photodynamic therapy leading to biofilm eradication on polyurethane catheter surfaces modified with hypericin nanoformulations.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {103},
number = {},
pages = {109749},
doi = {10.1016/j.msec.2019.109749},
pmid = {31349520},
issn = {1873-0191},
abstract = {Catheter related infections are causing one third of all blood stream infections. The mortality of those infections is very high and the gold standard for catheter related blood stream infections (CR-BSI) is still the removal of the catheter and systemic antibiotic therapy. There already exist some approaches to prevent the biofilm formation on catheter material, which are far from ideal. A new strategy to prevent bacterial colonization on catheter surfaces is the application of photodynamic therapy (PDT). Therefor the surface has to be modified with substances that can be activated by light, leading to the production of cell toxic reactive oxygen species (ROS). Only small concentrations of the so called photosensitizer (PS) are necessary, avoiding side effects in human therapy. Furthermore, there is no resistance development in PDT. In this study polyurethane (PUR) surfaces were coated with hypericin nanoformulations, leading to 4.3 log10 reduction in bacterial growth in vitro. The effect could be enhanced by the application of ultrasound. The combination of PDT with ultrasound therapy led to a synergistic effect resulting in a 6.8 log10 reduction of viable counts. This minimal invasive method requires only an optical fibre inserted in the catheter lumen and an ultrasound device. Thus the implementation in daily clinical practice is very simple.},
}
@article {pmid31349502,
year = {2019},
author = {Torres-Rêgo, M and Gláucia-Silva, F and Rocha Soares, KS and de Souza, LBFC and Damasceno, IZ and Santos-Silva, ED and Lacerda, AF and Chaves, GM and Silva-Júnior, AAD and Fernandes-Pedrosa, MF},
title = {Biodegradable cross-linked chitosan nanoparticles improve anti-Candida and anti-biofilm activity of TistH, a peptide identified in the venom gland of the Tityus stigmurus scorpion.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {103},
number = {},
pages = {109830},
doi = {10.1016/j.msec.2019.109830},
pmid = {31349502},
issn = {1873-0191},
abstract = {Among several bioactive peptides identified from the venom glands of the Tityus stigmurus scorpion, one peptide with hypotensive action (TistH, Tityus stigmurus Hypotensin) showed multifunctional and biotechnological applications. The maximum efficacy of this class of compounds can be achieved by immobilizing it in specific and suitable biomaterials or suitable carriers. In this study, distinct entrapment methods of TistH in chitosan nanoparticles was tested using its incorporation (CN-TistH-Inc) or adsorption (CN-TistH-Ads) methods by ionotropic gelification. Physico-chemical properties as well as biocompatibility and antifungal efficacy were assessed for different samples. Atomic force microscopy and field emission gun scanning electronic microscopy images associated with particle size measurements demonstrated that the two methods induced cationic spherical, small (< 160 nm), and narrow-sized (PdI about 0.3) nanoparticles, even after peptide loading greater than 96.5%, which was confirmed using Fourier transform infrared spectroscopy. The colloidal suspensions showed to be stable for 8 weeks and were able to induce the desired slow in vitro peptide release. Cytotoxicity assays performed in normal cells originated from murine macrophages (RAW 264.7) and kidneys of African green monkeys (Vero E6) suggested biocompatibility of samples. The CN-TistH-Inc and CN-TistH-Ads showed a minimal inhibitory concentration of 89.2 μg.mL-1 against Candida albicans, 11.1 μg.mL-1 for C. parapsilosis and C. tropicalis, confirmed by minimum fungicidal concentrations assay. Moreover, the TistH-loaded cross-linked chitosan nanoparticles significantly reduced the biofilm formation of clinical yeast sepsis of C. tropicalis and C. krusei, as well as clinical yeasts of vulvovaginal candidiasis of C. albicans. In this approach, biodegradable nanocarriers prepared using simple and reproducible methods demonstrated the ability to deliver the TistH peptide from T. stigmurus and improve its antifungal efficacy.},
}
@article {pmid31349480,
year = {2019},
author = {Hasan, N and Cao, J and Lee, J and Naeem, M and Hlaing, SP and Kim, J and Jung, Y and Lee, BL and Yoo, JW},
title = {PEI/NONOates-doped PLGA nanoparticles for eradicating methicillin-resistant Staphylococcus aureus biofilm in diabetic wounds via binding to the biofilm matrix.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {103},
number = {},
pages = {109741},
doi = {10.1016/j.msec.2019.109741},
pmid = {31349480},
issn = {1873-0191},
abstract = {Wounds infected with methicillin-resistant Staphylococcus aureus (MRSA) biofilm represent a high risk in patients with diabetes. Nitric oxide (NO) has shown promise in dispersing biofilm and wound healing. For an effective treatment of MRSA biofilm-infected wounds, however, NO needs to be supplied to the biofilm matrix in a sustainable manner due to a short half-life and limited diffusion distance of NO. In this study, polyethylenimine/diazeniumdiolate (PEI/NONOate)-doped PLGA nanoparticles (PLGA-PEI/NO NPs) with an ability to bind to the biofilm matrix are developed to facilitate the NO delivery to MRSA biofilm-infected wound. In simulated wound fluid, PLGA-PEI/NO NPs show an extended NO release over 4 days. PLGA-PEI/NO NPs firmly bind to the MRSA biofilm matrix, resulting in a greatly enhanced anti-biofilm activity. Moreover, PLGA-PEI/NO NPs accelerate healing of MRSA biofilm-infected wounds in diabetic mice along with complete biofilm dispersal and reduced bacterial burden. These results suggest that the biofilm-binding NO-releasing NPs represent a promising NO delivery system for the treatments of biofilm-infected chronic wounds.},
}
@article {pmid31349180,
year = {2019},
author = {di Biase, A and Kowalski, MS and Devlin, TR and Oleszkiewicz, JA},
title = {Moving bed biofilm reactor technology in municipal wastewater treatment: A review.},
journal = {Journal of environmental management},
volume = {247},
number = {},
pages = {849-866},
doi = {10.1016/j.jenvman.2019.06.053},
pmid = {31349180},
issn = {1095-8630},
abstract = {The review encompasses the development of municipal wastewater treatment process using MBBR from early stages, established application, and recent advancements. An overview of main drivers leading to the MBBR technology development over its early stage is discussed. Biocarriers types and features together with biofilm development and role of extracellular polymeric substances (EPS) are presented, ultimately, addressing the challenge in decreasing startup time required for full operation. Furthermore, the review investigates the state of the art of MBBR technology for nutrient removal (i.e., COD and BOD, nitrogen and phosphorus) through process functionality and configuration of established (e.g., IFAS) and under development (e.g. PN/A) applications. Reactor operational characteristics such as filling fractions, mixing properties, dissolved oxygen requirements, and loading rates are presented and related to full scale examples. Current literature discussing the most recent studies on MBBR capability in reduction and removal of chemicals of emerging concern (CEC) released is presented. Ultimately, high rate carbon and nitrogen removal through A/B stage process are examined in its main operational parameters and its application towards energy neutrality suggesting novel MBBR application to further reduce energy requirements and plant footprint.},
}
@article {pmid31347191,
year = {2019},
author = {Kannan, S and Krishnamoorthy, G and Kulanthaiyesu, A and Marudhamuthu, M},
title = {Effect of biosurfactant derived from Vibrio natriegens MK3 against Vibrio harveyi biofilm and virulence.},
journal = {Journal of basic microbiology},
volume = {59},
number = {9},
pages = {936-949},
doi = {10.1002/jobm.201800706},
pmid = {31347191},
issn = {1521-4028},
support = {//Department of Biotechnology, Interdisciplinary Programme in Life Sciences/ ; //University Grants Commission (UGC-NFOBC)/ ; },
abstract = {Vibrio harveyi is a marine luminous pathogen, which causes biofilm-mediated infections, pressures the search for an innovative alternate approach to strive against vibriosis in aquaculture. This study anticipated to explore the effect of glycolipid biosurfactant as an antipathogenic against V. harveyi to control vibriosis. In this study, 27 bacterial strains were isolated from marine soil sediments. Out of these, 11 strains exhibited surfactant activity and the strain MK3 showed high emulsification index. The potent strain was identified as Vibrio natriegens and named as V. natriegens MK3. The extracted biosurfactant was purified using high-performance liquid chromatography and it was efficient to decrease the surface tension of the growth medium up to 21 mN/m. The functional group and composition of the biosurfactant were determined by Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy spectral studies and the nature of the biosurfactant was identified as glycolipid. The surfactant was capable of reducing the biofilm formation, bioluminescence, extracellular polysaccharide synthesis, and quorum sensing in marine shrimp pathogen V. harveyi. The antagonistic effect of biosurfactant was evaluated against V. harveyi-infected brine shrimp Artemia salina. This study reveals that biosurfactant can be considered for the management of biofilm-related aquatic infections.},
}
@article {pmid31346374,
year = {2019},
author = {Listiana-Kriswandini, I and Budi-Rahardjo, M and Soesilawati, P and Prisca-Suciadi, A},
title = {Detection of Candida albicans biofilm proteins induced by glucose, lactose, soy protein, and iron.},
journal = {Journal of clinical and experimental dentistry},
volume = {11},
number = {6},
pages = {e542-e546},
doi = {10.4317/jced.55787},
pmid = {31346374},
issn = {1989-5488},
abstract = {Background: Oral candidiasis is one of the most common fungal infections, which attack the mucosa of the oral cavity. These lesions are mostly caused by the fungal species Candida albicans. Candida albicans is included in the normal oral microorganisms that are opportunistic pathogens, and its presence is quite large, which can reach 75% of the total oral fungal population. Research on specific proteins of Candida biofilm can be an alternative to early prevention of oral infections such as Oral Candidiasis. This biofilm protein can be used as a reference in making kits to detect the presence of microbes that cause infectious diseases. The purpose of this study was to determine molecular weight of Candida albicans biofilm protein induced by 5% glucose, 5% lactose, soy protein, and 5% iron.<br><br>Material and Methods: This experimental laboratory study used SDS-PAGE electrophoresis to determine the molecular weight of Candida albicans biofilm proteins induced by glucose 5%, lactose 5%, soy protein, and iron 5%.<br><br>Results: Biofilm induced by 5% glucose shows four protein bands: 71,6 kDa; 56,1 kDa; 49,7 kDa; and 41 kDa. Biofilm induced by 5% lactose shows seven protein bands: 71 kDa; 61,2 kDa; 57,7 kDa; 55,3 kDa; 48,9 kDa; 39,5 kDa; and 29,8 kDa. Biofilm induced by soy protein shows one protein band: 49,4 kDa. Biofilm induced by 5% iron shows one protein band: 51,1 kDa.<br><br>Conclusions: Candida albicans biofilm induced by 5% glucose has four protein band candidates, 5% lactose has seven candidates of protein band, and soy protein and 5% iron each has a candidate of protein band, which can be used as a target for the detection of oral Candidiasis. Key words:Biofilm protein, Candida albicans, molecular weight, oral candidiasis.},
}
@article {pmid31345229,
year = {2019},
author = {Besser, M and Terberger, J and Weber, L and Ghebremedhin, B and Naumova, EA and Arnold, WH and Stuermer, EK},
title = {Impact of probiotics on pathogen survival in an innovative human plasma biofilm model (hpBIOM).},
journal = {Journal of translational medicine},
volume = {17},
number = {1},
pages = {243},
doi = {10.1186/s12967-019-1990-4},
pmid = {31345229},
issn = {1479-5876},
support = {IFF2018-61//University of Witten/Herdecke/ ; },
abstract = {BACKGROUND: Despite of medical advances, the number of patients suffering on non-healing chronic wounds is still increasing. This fact is attended by physical and emotional distress and an economic load. The majority of chronic wounds are infected of harmful microbials in a protecting extracellular matrix. These biofilms inhibit wound healing. Biofilm-growing bacteria developed unique survival properties, which still challenge the appropriate wound therapy. The present in-vitro biofilm models are not suitable for translational research. By means of a novel in-vivo like human plasma biofilm model (hpBIOM), this study systematically analysed the influence of 3 probiotics on the survival of five clinically relevant pathogenic microorganisms.<br><br>METHODS: Human plasma was used to produce the innovate biofilm. Pathogenic microorganisms were administered to the plasma. By stimulating the production of a fibrin scaffold, stable coagula-like discs with integrated pathogens were produced. The five clinically relevant pathogens P. aeruginosa, S. aureus, S. epidermidis, E. faecium and C. albicans were challenged to the probiotics L. plantarum, B. lactis and S. cerevisiae. The probiotics were administered on top of the biofilm and the survival was quantified after 4 h and 24 h of incubation. For statistics, two-way ANOVA with post-hoc Tukey's HSD test was applied. P-value > 0.05 was considered to be significant.<br><br>RESULTS: SEM micrographs depicted the pathogens on the surface of the fibrin scaffold, arranged in close proximity and produced the glycocalyx. The application of probiotics induced different growth-reducing capacities towards the pathogens. B. lactis and S. cerevisiae showed slight bacteria-reducing properties. The survival of C. albicans was not affected at all. The most antimicrobial activity was detected after the treatment with L. plantarum.<br><br>CONCLUSIONS: This study successfully reproduced a novel human biofilm model, which provides a human wound milieu and individual immune competence. The success of bacteriotherapy is dependent on the strain combination, the number of probiotics and the activity of the immune cells. The eradicating effect of L. plantarum on P. aeruginosa should be emphasized.},
}
@article {pmid31344909,
year = {2019},
author = {Zhang, T and Ying, D and Qi, M and Li, X and Fu, L and Sun, X and Wang, L and Zhou, Y},
title = {Anti-Biofilm Property of Bioactive Upconversion Nanocomposites Containing Chlorin e6 against Periodontal Pathogens.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {15},
pages = {},
doi = {10.3390/molecules24152692},
pmid = {31344909},
issn = {1420-3049},
support = {81570983//National Natural Science Foundation of China/ ; 20180414030GH//International Cooperation Project of Science and Technology Development Jilin Province/ ; },
abstract = {Photodynamic therapy (PDT) based periodontal disease treatment has received extensive attention. However, the deep tissue location of periodontal plaque makes the conventional PDT encounter a bottleneck. Herein, upconversion fluorescent nanomaterial with near-infrared light excitation was introduced into the treatment of periodontal disease, overcoming the limited tissue penetration depth of visible light in PDT. Photosensitizer Ce6 molecules were combined with upconversion nanoparticles (UCNPs) NaYF4:Yb,Er with a novel strategy. The hydrophobic UCNPs were modified with amphiphilic silane, utilizing the hydrophobic chain of the silane to bind to the hydrophobic groups of the UCNPs through a hydrophobic-hydrophobic interaction, and the Ce6 molecules were loaded in this hydrophobic layer. This achieves both the conversion of the hydrophobic to the hydrophilic surface and the loading of the oily photosensitizer molecules. Because the excitation position of the Ce6 molecule is in the red region, Mn ions were doped to enhance red light, and thus the improved PDT function. This Ce6 loaded UCNPs composites with efficient red upconversion luminescence show remarkable bacteriological therapeutic effect on Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum and the corresponding biofilms under 980 nm irradiation, indicating a high application prospect in the treatment of periodontal diseases.},
}
@article {pmid31344638,
year = {2019},
author = {Jensen, MB and Strübing, D and de Jonge, N and Nielsen, JL and Ottosen, LDM and Koch, K and Kofoed, MVW},
title = {Stick or leave - Pushing methanogens to biofilm formation for ex situ biomethanation.},
journal = {Bioresource technology},
volume = {291},
number = {},
pages = {121784},
doi = {10.1016/j.biortech.2019.121784},
pmid = {31344638},
issn = {1873-2976},
mesh = {*Biofilms ; Biomass ; Bioreactors ; Euryarchaeota/*physiology ; Methane/*metabolism ; Plankton/metabolism ; },
abstract = {Biomethanation exploits the ability of methanogenic archaea to convert CO2 and renewable H2 from electrolysis to biomethane. Biofilm reactors are promising for biomethanation scale-up due to high CH4 productivity and low energy input for H2 gas-liquid mass transfer. Effects of operational conditions on biofilm dynamics remain largely uncharacterized but may increase reactor potentials further. This study investigated the effect of hydraulic retention time (HRT) on methanogenic biofilm activity and composition. Commercial carriers floating in liquid were exposed to H2/CO2 for 87 days with the liquid phase being subject to either 18 hours, 10 days, or 20 days HRT. Methanogenic biofilms were dominated by hydrogenotrophic methanogens, but biofilm CH4 productivity was enhanced at 18 hours HRT due to wash-out of competing planktonic species, which otherwise hampered proliferation of biofilm biomass at long HRT. It is suggested that high-rate biofilm reactors can increase methanogenic biofilm activity by minimizing the liquid's H2 exposure.},
}
@article {pmid31344634,
year = {2019},
author = {Song, T and Li, S and Jin, J and Yin, Z and Lu, Y and Bao, M and Li, Y},
title = {Enhanced hydrolyzed polyacrylamide removal from water by an aerobic biofilm reactor-ozone reactor-aerobic biofilm reactor hybrid treatment system: Performance, key enzymes and functional microorganisms.},
journal = {Bioresource technology},
volume = {291},
number = {},
pages = {121811},
doi = {10.1016/j.biortech.2019.121811},
pmid = {31344634},
issn = {1873-2976},
abstract = {Degradation of hydrolyzed polyacrylamide-containing (HPAM-containing) wastewater was investigated in a lab-scale aerobic-ozonic-aerobic hybrid treatment system. When the HPAM concentration was 500 mg L-1 and the ozone dose was 25 g O3/g TOC, the HPAM removal rate reached 90.79%. Experimental results obtained from gel permeation chromatography (GPC) and rheometer indicated that the refractory HPAM was decomposed into small-molecule compounds. High performance liquid chromatography (HPLC) analysis showed that there was no acrylamide (AM) in the effluent of the system. Microbial communities in two aerobic biofilm reactors (ABRs) were analyzed by Illumina MiSeq Sequencing, which indicated that norank_f_Cytophagaceae, Meiothermus, Bacillus, etc. were keystone functional bacterial genera and Methanobacterium, norank_p_Bathyarchaeota, norank_c_Marine_Group_Ⅰ, etc. were dominant functional archaeal groups. To our knowledge, this is the first study to treat HPAM-containing wastewater using an aerobic-ozonic-aerobic hybrid process. Good removal efficiencies and presence of functional microorganisms demonstrated that the hybrid treatment system was practical for treating HPAM-containing wastewater.},
}
@article {pmid31342619,
year = {2019},
author = {Sivadon, P and Barnier, C and Urios, L and Grimaud, R},
title = {Biofilm formation as a microbial strategy to assimilate particulate substrates.},
journal = {Environmental microbiology reports},
volume = {},
number = {},
pages = {},
doi = {10.1111/1758-2229.12785},
pmid = {31342619},
issn = {1758-2229},
support = {BIOLEO//Conseil Général des Pyrénées Atlantiques/ ; },
abstract = {In most ecosystems, a large part of the organic carbon is not solubilized in the water phase. Rather, it occurs as particles made of aggregated hydrophobic and/or polymeric natural or man-made organic compounds. These particulate substrates are degraded by extracellular digestion/solubilization implemented by heterotrophic bacteria that form biofilms on them. Organic particle-degrading biofilms are widespread and have been observed in aquatic and terrestrial natural ecosystems, in polluted and man-driven environments and in the digestive tracts of animals. They have central ecological functions as they are major players in carbon recycling and pollution removal. The aim of this review is to highlight bacterial adhesion and biofilm formation as central mechanisms to exploit the nutritive potential of organic particles. It focuses on the mechanisms that allow access and assimilation of non-dissolved organic carbon, and considers the advantage provided by biofilms for gaining a net benefit from feeding on particulate substrates. Cooperative and competitive interactions taking place in biofilms feeding on particulate substrates are also discussed.},
}
@article {pmid31341834,
year = {2019},
author = {Gawish, S and Abbass, A and Abaza, A},
title = {Occurrence and biofilm forming ability of Pseudomonas aeruginosa in the water output of dental unit waterlines in a dental center in Alexandria, Egypt.},
journal = {Germs},
volume = {9},
number = {2},
pages = {71-80},
doi = {10.18683/germs.2019.1160},
pmid = {31341834},
issn = {2248-2997},
abstract = {Introduction: Dental unit waterlines (DUWLs) are notorious for being contaminated with different bacterial species including the opportunistic pathogen Pseudomonas aeruginosa which poses a risk to patients and professionals. This work aimed at studying the occurrence and biofilm-forming ability (BFA) of P. aeruginosa in the output of DUWLs in a dental center in Egypt.<br><br>Methods: Water samples were collected from the outlets of the high-speed hand piece, the air/water syringe and the cup filler waterlines. Bacteriological analysis included heterotrophic plate count (HPC), isolation and identification of P. aeruginosa and determination of the antimicrobial susceptibility and the BFA of the isolates by tissue culture plate (TCP) method and tube method (TM).<br><br>Results: The average concentration of HPC bacteria in the output of the 3 DUWLs was 2.9×104 CFU/μL where 88.3% of the samples exceeded the Egyptian standards for drinking water (<50 CFU L). P. aeruginosa was isolated from nine cup filler samples (which had a water source different from the other waterlines). The isolates were sensitive to all tested antimicrobials. Of these nine isolates, 6, 5 and 4 were positive for BFA by TCP, modified TCP and TM, respectively.<br><br>Conclusions: More stringent measures are required to ensure safer dental water; as the majority of studied samples exceeded the required HPC bacterial limit and P. aeruginosa isolates were detected. P. aeruginosa isolates from DUWLs may not be as resistant to antibiotics as what is reported in the literature about clinical isolates. Some P. aeruginosa isolates can colonize DUWLs despite their inability to form biofilms in experimental testing.},
}
@article {pmid31341833,
year = {2019},
author = {Ahmed, DM and Messih, MAWA and Ibrahim, NH and Meabed, MH and Abdel-Salam, SM},
title = {Frequency of icaA and icaD determinants and biofilm formation among coagulase-negative staphylococci associated with nasal carriage in neonatal intensive care units.},
journal = {Germs},
volume = {9},
number = {2},
pages = {61-70},
doi = {10.18683/germs.2019.1159},
pmid = {31341833},
issn = {2248-2997},
abstract = {Introduction: Nasal colonization with coagulase-negative staphylococci (CoNS) may be a preliminary risk factor for systemic infection. The aim of this study was to assess the frequency of ica A and D genes and biofilm formation among hospital-acquired nasal colonizing CoNS strains isolated from neonates in the neonatal intensive care units (NICUs). Antibiotic sensitivity patterns and some relevant risk factors were estimated.<br><br>Methods: This study assessed nasal colonization with CoNS among neonates at days one and three of admission to NICUs of Beni-Suef University Hospital and Beni-Suef General Hospital from November 2015 to May 2016. The isolates were screened and identified; susceptibility testing was performed. Biofilm formation was examined using the Congo red agar method. Isolates identified as CoNS were tested by polymerase chain reaction (PCR) for the presence of mecA and icaA and icaD genes.<br><br>Results: A total of 340 nasal swabs were collected from 170 neonates. The incidence of nasal colonization with CoNS was 50%. The species most frequently isolated were S. haemolyticus and S. epidermidis. Multidrug resistance (MDR) was detected in 86% of isolates. It was found that there was a strong association between the presence of mecA gene and phenotypic resistance to methicillin and also the presence of the icaA gene and biofilm formation.<br><br>Conclusions: Neonates admitted to NICUs can become reservoirs for CoNS strains, leading to potential dissemination of MDR strains into the community.},
}
@article {pmid31340580,
year = {2019},
author = {Bessa, LJ and Manickchand, JR and Eaton, P and Leite, JRSA and Brand, GD and Gameiro, P},
title = {Intragenic Antimicrobial Peptide Hs02 Hampers the Proliferation of Single- and Dual-Species Biofilms of P. aeruginosa and S. aureus: A Promising Agent for Mitigation of Biofilm-Associated Infections.},
journal = {International journal of molecular sciences},
volume = {20},
number = {14},
pages = {},
doi = {10.3390/ijms20143604},
pmid = {31340580},
issn = {1422-0067},
support = {UID/QUI/50006/2019//FCT/MCTES through national funds/ ; 0193.000866/2015//FAP-DF/ ; },
abstract = {Pseudomonas aeruginosa and Staphylococcus aureus are two major pathogens involved in a large variety of infections. Their co-occurrence in the same site of infection has been frequently reported and is linked to enhanced virulence and difficulty of treatment. Herein, the antimicrobial and antibiofilm activities of an intragenic antimicrobial peptide (IAP), named Hs02, which was uncovered from the human unconventional myosin 1H protein, were investigated against several P. aeruginosa and S. aureus strains, including multidrug-resistant (MDR) isolates. The antibiofilm activity was evaluated on single- and dual-species biofilms of P. aeruginosa and S. aureus. Moreover, the effect of peptide Hs02 on the membrane fluidity of the strains was assessed through Laurdan generalized polarization (GP). Minimum inhibitory concentration (MIC) values of peptide Hs02 ranged from 2 to 16 μg/mL against all strains and MDR isolates. Though Hs02 was not able to hamper biofilm formation by some strains at sub-MIC values, it clearly affected 24 h preformed biofilms, especially by reducing the viability of the bacterial cells within the single- and dual-species biofilms, as shown by confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) images. Laurdan GP values showed that Hs02 induces membrane rigidification in both P. aeruginosa and S. aureus. Peptide Hs02 can potentially be a lead for further improvement as an antibiofilm agent.},
}
@article {pmid31340472,
year = {2019},
author = {Al-Bakri, AG and Mahmoud, NN},
title = {Photothermal-Induced Antibacterial Activity of Gold Nanorods Loaded into Polymeric Hydrogel against Pseudomonas aeruginosa Biofilm.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {14},
pages = {},
doi = {10.3390/molecules24142661},
pmid = {31340472},
issn = {1420-3049},
support = {1820-1104//the Deanship of Scientific Research at The University of Jordan/ ; 2017-2016/64/04//Deanship of Scientific Research and Graduate Studies at Al-Zaytoonah University of Jordan/ ; 3/2017//Abdul Hameed Shoman Foundation, Amman, Jordan/ ; },
abstract = {In this study, the photothermal-induced bactericidal activity of phospholipid-decorated gold nanorods (DSPE-AuNR) suspension against Pseudomonas aeruginosa planktonic and biofilm cultures was investigated. We found that the treatment of planktonic culture of Pseudomonas aeruginosa with DSPE-AuNR suspension (0.25-0.03 nM) followed by a continuous laser beam exposure resulted in ~6 log cycle reduction of the bacterial viable count in comparison to the control. The percentage reduction of Pseudomonas aeruginosa biofilm viable count was ~2.5-6.0 log cycle upon laser excitation with different concentrations of DSPE-AuNR as compared to the control. The photothermal ablation activity of DSPE-AuNR (0.125 nM) loaded into poloxamer 407 hydrogel against Pseudomonas aeruginosa biofilm resulted in ~4.5-5 log cycle reduction in the biofilm viable count compared to the control. Moreover, transmission electron microscope (TEM) images of the photothermally-treated bacteria revealed a significant change in the bacterial shape and lysis of the bacterial cell membrane in comparison to the untreated bacteria. Furthermore, the results revealed that continuous and pulse laser beam modes effected a comparable photothermal-induced bactericidal activity. Therefore, it can be concluded that phospholipid-coated gold nanorods present a promising nanoplatform to eradicate Pseudomonas aeruginosa biofilm responsible for common skin diseases.},
}
@article {pmid31338728,
year = {2019},
author = {Zaatout, N and Ayachi, A and Kecha, M},
title = {Epidemiological investigation of subclinical bovine mastitis in Algeria and molecular characterization of biofilm-forming Staphylococcus aureus.},
journal = {Tropical animal health and production},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11250-019-02015-9},
pmid = {31338728},
issn = {1573-7438},
abstract = {Thirty dairy farms were selected for this study; the first objective of our study was to investigate the prevalence of subclinical bovine mastitis (SCM) in Eastern Algeria, from 600 lactating cows, and to identify potential risk factors associated with the occurrence of bovine mastitis and bacteria isolation using logistic regression. The second objective was to evaluate biofilm formation capacity and detect biofilm-associated genes of S. aureus, isolated from SCM cases. Molecular typing was investigated by spa typing. The prevalence of mastitis at cow and quarter level was 37.66% (226/600) and 27.17% (555/2042), respectively. Stage of lactation, cow breed, milk production, and the study area were factors associated with SCM. In addition, the most frequent pathogens isolated from mastitic milk were coagulase-negative staphylococci (CNS), E. coli, and S. aureus. The study area was highly associated with SCM caused by S. aureus; cows from Setif province were 18 times more affected with SCM caused by S. aureus compared to cows from Batna province (OR = 18.6, 95%CI 2.038-171.2), but were less affected with SCM caused by CNS isolates (OR = 0.17, 95%CI 0.033-0.868). Moreover, cows with milk production less than 10 L per day increased (p < 0.05) the prevalence of mastitis caused by E. coli. All the S. aureus isolates had biofilm-forming ability, and 41.66% of isolates were positive for adhesion genes (icaA, icaD, fbnA, and clfA). This study, therefore, warrants the need for improving sanitary measures and strict hygienic measures, and presents the first insight into biofilm-forming ability of S. aureus strains causing mastitis in dairy herds in Algeria, which will help in tracking the evolution of epidemic strains responsible for causing bovine mastitis.},
}
@article {pmid31338076,
year = {2019},
author = {Alviz-Gazitua, P and Fuentes-Alburquenque, S and Rojas, LA and Turner, RJ and Guiliani, N and Seeger, M},
title = {The Response of Cupriavidus metallidurans CH34 to Cadmium Involves Inhibition of the Initiation of Biofilm Formation, Decrease in Intracellular c-di-GMP Levels, and a Novel Metal Regulated Phosphodiesterase.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1499},
doi = {10.3389/fmicb.2019.01499},
pmid = {31338076},
issn = {1664-302X},
abstract = {Cadmium is a highly toxic heavy metal for biological systems. Cupriavidus metallidurans CH34 is a model strain to study heavy metal resistance and bioremediation as it is able to deal with high heavy metal concentrations. Biofilm formation by bacteria is mediated by the second messenger bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP). The aim of this study was to characterize the response of C. metallidurans CH34 planktonic and biofilm cells to cadmium including their c-di-GMP regulatory pathway. Inhibition of the initiation of biofilm formation and EPS production by C. metallidurans CH34 correlates with increased concentration of cadmium. Planktonic and biofilm cells showed similar tolerance to cadmium. During exposure to cadmium an acute decrease of c-di-GMP levels in planktonic and biofilm cells was observed. Transcription analysis by RT-qPCR showed that cadmium exposure to planktonic and biofilm cells induced the expression of the urf2 gene and the mercuric reductase encoding merA gene, which belong to the Tn501/Tn21 mer operon. After exposure to cadmium, the cadA gene involved in cadmium resistance was equally upregulated in both lifestyles. Bioinformatic analysis and complementation assays indicated that the protein encoded by the urf2 gene is a functional phosphodiesterase (PDE) involved in the c-di-GMP metabolism. We propose to rename the urf2 gene as mrp gene for metal regulated PDE. An increase of the second messenger c-di-GMP content by the heterologous expression of the constitutively active diguanylate cyclase PleD correlated with an increase in biofilm formation and cadmium susceptibility. These results indicate that the response to cadmium in C. metallidurans CH34 inhibits the initiation of biofilm lifestyle and involves a decrease in c-di-GMP levels and a novel metal regulated PDE.},
}
@article {pmid31336660,
year = {2019},
author = {Cadena, M and Kelman, T and Marco, ML and Pitesky, M},
title = {Understanding Antimicrobial Resistance (AMR) Profiles of Salmonella Biofilm and Planktonic Bacteria Challenged with Disinfectants Commonly Used During Poultry Processing.},
journal = {Foods (Basel, Switzerland)},
volume = {8},
number = {7},
pages = {},
doi = {10.3390/foods8070275},
pmid = {31336660},
issn = {2304-8158},
abstract = {Foodborne pathogens such as Salmonella that survive cleaning and disinfection during poultry processing are a public health concern because pathogens that survive disinfectants have greater potential to exhibit resistance to antibiotics and disinfectants after their initial disinfectant challenge. While the mechanisms conferring antimicrobial resistance (AMR) after exposure to disinfectants is complex, understanding the effects of disinfectants on Salmonella in both their planktonic and biofilm states is becoming increasingly important, as AMR and disinfectant tolerant bacteria are becoming more prevalent in the food chain. This review examines the modes of action of various types of disinfectants commonly used during poultry processing (quaternary ammonium, organic acids, chlorine, alkaline detergents) and the mechanisms that may confer tolerance to disinfectants and cross-protection to antibiotics. The goal of this review article is to characterize the AMR profiles of Salmonella in both their planktonic and biofilm state that have been challenged with hexadecylpyridinium chloride (HDP), peracetic acid (PAA), sodium hypochlorite (SHY) and trisodium phosphate (TSP) in order to understand the risk of these disinfectants inducing AMR in surviving bacteria that may enter the food chain.},
}
@article {pmid31336253,
year = {2019},
author = {Tian, Z and Liu, R and Zhang, H and Yang, M and Zhang, Y},
title = {Developmental dynamics of antibiotic resistome in aerobic biofilm microbiota treating wastewater under stepwise increasing tigecycline concentrations.},
journal = {Environment international},
volume = {131},
number = {},
pages = {105008},
doi = {10.1016/j.envint.2019.105008},
pmid = {31336253},
issn = {1873-6750},
abstract = {This study aimed to investigate the impact of tigecycline, the third generation tetracycline, on the antibiotic resistance development in environmental microbiota. Two biological contact oxidation reactors containing aerobic biofilm microbiota were constructed, one of which was constantly fed with synthetic wastewater spiked with increasing concentrations of tigecycline (0 to 25 mg/L) under a hydrolytic retention time of 24 h. Over a period of 636 days, chemical oxygen demand removal over 90% and complete nitrification were achieved for both the control and tigecycline-exposed reactors, and effluent tigecycline concentrations in the tigecycline-exposed system were always <0.051 mg/L. Significant increases (p < 0.01) in resistome abundance and resistant bacteria ratio were detected at a tigecycline dose of 10 and 25 mg/L, respectively, revealed by metagenomic sequencing and culture-based method. The increase of resistome in the tigecycline system was mainly attributed to the enrichment of tetX, one cooperative tetracycline degrading gene. Partial canonical correspondence analysis showed that the change of resistome was mainly driven by bacterial community shift (vertical pathway). Network and genome binning analyses further suggested that the proliferation of Flavobacterium harboring tetX contributed to a relatively low community-wide resistance development in the aerobic biofilm microbiota under tigecycline selection by reducing the antibiotic concentration. This work provides scientific bases for the management and evaluation of the resistance risk induced by this novel antibiotic.},
}
@article {pmid31336203,
year = {2019},
author = {Chávez-Andrade, GM and Tanomaru-Filho, M and Basso Bernardi, MI and de Toledo Leonardo, R and Faria, G and Guerreiro-Tanomaru, JM},
title = {Antimicrobial and biofilm anti-adhesion activities of silver nanoparticles and farnesol against endodontic microorganisms for possible application in root canal treatment.},
journal = {Archives of oral biology},
volume = {107},
number = {},
pages = {104481},
doi = {10.1016/j.archoralbio.2019.104481},
pmid = {31336203},
issn = {1879-1506},
abstract = {OBJECTIVE: This study aimed to evaluate the antimicrobial and biofilm anti-adhesion activities of poly(vinyl alcohol)-coated silver nanoparticles (AgNPs-PVA) and farnesol against Enterococcus faecalis, Candida albicans or Pseudomonas aeruginosa.<br><br>DESIGN: Minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) of the solutions, as well as the effect on the biofilm biomass were evaluated. The biofilm anti-adhesion activity was evaluated using bovine root dentine treated with the solutions after 3 min of contact and analyzed by scanning electron microscopy (SEM) and by colony-forming units per milliliter (CFU mL-1) counting. Data were analyzed using ANOVA and Tukey's, the paired Student's t-test or Kruskal-Wallis and Dunn's tests (α = 0.05).<br><br>RESULTS: The MIC and MMC values (MIC/MMC) of the AgNPs-PVA and farnesol against E. faecalis were 42.5/50 μM and 0.85/1.0%, respectively. For C. albicans, the values were 27.5/37.5 μM and 1.75/2.5%; and for P. aeruginosa, 32.5/32.5 μM and 2.5/2.75%, respectively. Both solutions showed reduced biofilm biomass (p < 0.05). SEM analysis showed that dentine blocks treated with both solutions had lower biofilm formation than the control (saline), except for C. albicans. In the CFU mL-1 counting, biofilm cells were viable in the all groups in comparison with control (p > 0.05).<br><br>CONCLUSIONS: AgNPs-PVA and farnesol showed antimicrobial and biofilm anti-adhesion activities, as well as potential for use as coadjuvant in endodontic treatment, and may be an option as auxiliary procedure for root canal disinfection or to inhibit biofilm formation.},
}
@article {pmid31335442,
year = {2019},
author = {Munro, APS and Highmore, CJ and Webb, JS and Faust, SN},
title = {Diagnosis and treatment of biofilm infections in children.},
journal = {Current opinion in infectious diseases},
volume = {32},
number = {5},
pages = {505-509},
doi = {10.1097/QCO.0000000000000582},
pmid = {31335442},
issn = {1473-6527},
abstract = {PURPOSE OF REVIEW: Biofilm-associated infections cause difficulties in the management of childhood chronic infections and other diseases, due to the invasive nature of interventions which are often necessary for definitive management. Despite their importance, there are challenges in diagnosing biofilm infections and gaps in clinicians' understanding regarding the significance of biofilms.<br><br>RECENT FINDINGS: Many chronic infections associated with biofilms remain difficult or impossible to eradicate with conventional therapy. Surgical intervention, implant removal or long-term intermittent or suppressive antimicrobial therapy may be required. There are still significant challenges in detecting biofilms which presents a barrier in clinical practice and research. Novel therapies to disrupt biofilms are currently under investigation, which may help reduce the impact of antimicrobial resistance.<br><br>SUMMARY: Biofilm-associated infection should be considered wherever there is clinical concern for an infection affecting prosthetic material, where there is a predisposing condition such as suppurative lung disease; or in the setting of chronic or relapsing infections which may be culture negative. New diagnostic methods for detecting biofilms are a research priority for both clinical diagnosis and the ability to conduct high quality clinical trials of novel antibiofilm interventions.},
}
@article {pmid31335187,
year = {2019},
author = {Devivilla, S and Lekshmi, M and Kumar, SH and Valappil, RK and Roy, SD and Nayak, BB},
title = {Effect of Sodium Hypochlorite on Biofilm-Forming Ability of Histamine-Producing Bacteria Isolated from Fish.},
journal = {Journal of food protection},
volume = {82},
number = {8},
pages = {1417-1422},
doi = {10.4315/0362-028X.JFP-19-101},
pmid = {31335187},
issn = {1944-9097},
abstract = {Histamine poisoning occurs when temperature-abused marine fish containing elevated levels of histamine are consumed. Histamine-producing bacteria found in fish can colonize processing surfaces and form biofilms. In this study, the biofilm-forming abilities of histamine-producing bacteria from Indian mackerel (Rastrelliger kanagurta) and the effect of hypochlorite treatment on biofilm formation were studied. The isolates of this study produced histamine in the range of 471 to 2,126 ppm. The histidine decarboxylase gene hdc was detected in all isolates producing histamine except in one strain each of Psychrobacter pulmonis and Proteus vulgaris. All isolates tested in this study produced moderate biofilms under control conditions, whereas exposure to 1 and 3 ppm of sodium hypochlorite significantly enhanced biofilm formation. However, exposure to 5 ppm of sodium hypochlorite showed an inhibitory effect on biofilm formation by all the isolates except Klebsiella variicola. The results of this study suggest that histamine-producing bacteria can form stable biofilms and that this activity may be enhanced by the application of low levels of sodium hypochlorite, a phenomenon that might influence the persistence of histamine-producing bacteria in fish processing areas.},
}
@article {pmid31332872,
year = {2019},
author = {Wang, Y and Du, Z and Liu, Y and Wang, H and Xu, F and Liu, B and Zheng, Z},
title = {The nitrogen removal and sludge reduction performance of a multi-stage anoxic/oxic (A/O) biofilm reactor.},
journal = {Water environment research : a research publication of the Water Environment Federation},
volume = {},
number = {},
pages = {},
doi = {10.1002/wer.1188},
pmid = {31332872},
issn = {1554-7531},
support = {ZR2016EEM32//Natural Science Foundation of Shandong Province/ ; 2015GSF117003//Shandong Province Key Development Projects/ ; SFSJKY2018-01//Scientific and Technological Innovation Project of Planning and Design Institute of Huaihe River Basin Water Conservancy Administration Bureau of Shandong Province in 2018/ ; 51878394//National Natural Science Foundation/ ; UDC2017031612//Science and Technology Plans of Ministry of Housing and Urban-Rural Development of the People's Republic of China, and Opening Projects of Beijing Advanced Innovation Center for Future Urban Design, Beijing University of Civil Engineering and Architecture/ ; },
abstract = {To overcome the problems of high excess sludge yield and poor nitrogen removal efficiency in traditional biological treatment processes, a multi-stage A/O biofilm reactor was developed by combining the multi-stage A/O process with novel floating spherical carriers, resulting in repeated coupling of anoxic and aerobic environments. Results showed that the system achieved COD, NH 4 + - N , and TN removal efficiencies of 93.8%, 84.5%, and 75.7%, respectively, with average effluent concentrations lower than: 29.8 COD mg/L, 4.3 NH 4 + - N mg/L, and 13.2 TN mg/L. The observed sludge yield was 0.139 g MLSS/g COD, which was lower than that of the conventional activated sludge process. Microbial analysis showed that the community structure and cell morphology of microorganisms changed greatly with alternating aerobic-anoxic condition; high-throughput sequencing results proved that functional microorganisms can be enriched on the surface of the carries and therefore improved the nitrogen removal efficiency and meanwhile minimize the sludge yield within the system. PRACTITIONER POINTS: The research innovatively developed a novel floating spherical carrier and coupled it with multi-stage A/O process. The complex redox environments inside the floating spherical carriers improves the nitrogen removal efficiency and the sludge reduction effect. Nitrospirae, Hydrogenophaga promoted the nitrogen removal, Firmicutes, Bacteroidetes and Dechloromonas promoted the in-situ sludge reduction of the system.},
}
@article {pmid31331112,
year = {2019},
author = {Glasenapp, Y and Cattò, C and Villa, F and Saracchi, M and Cappitelli, F and Papenbrock, J},
title = {Promoting Beneficial and Inhibiting Undesirable Biofilm Formation with Mangrove Extracts.},
journal = {International journal of molecular sciences},
volume = {20},
number = {14},
pages = {},
doi = {10.3390/ijms20143549},
pmid = {31331112},
issn = {1422-0067},
support = {57265315//MIUR-DAAD Joint Mobility Program/ ; },
abstract = {The extracts of two mangrove species, Bruguieracylindrica and Lagunculariaracemosa, have been analyzed at sub-lethal concentrations for their potential to modulate biofilm cycles (i.e., adhesion, maturation, and detachment) on a bacterium, yeast, and filamentous fungus. Methanolic leaf extracts were also characterized, and MS/MS analysis has been used to identify the major compounds. In this study, we showed the following. (i) Adhesion was reduced up to 85.4% in all the models except for E. coli, where adhesion was promoted up to 5.10-fold. (ii) Both the sum and ratio of extracellular polysaccharides and proteins in mature biofilm were increased up to 2.5-fold and 2.6-fold in comparison to the negative control, respectively. Additionally, a shift toward a major production of exopolysaccharides was found coupled with a major production of both intracellular and extracellular reactive oxygen species. (iii) Lastly, detachment was generally promoted. In general, the L.racemosa extract had a higher bioactivity at lower concentrations than the B.cylindrica extract. Overall, our data showed a reduction in cells/conidia adhesion under B.cylindrica and L.racemosa exposure, followed by an increase of exopolysaccharides during biofilm maturation and a variable effect on biofilm dispersal. In conclusion, extracts either inhibited or enhanced biofilm development, and this effect depended on both the microbial taxon and biofilm formation step.},
}
@article {pmid31330991,
year = {2019},
author = {Vitale, M and Galluzzo, P and Buffa, PG and Carlino, E and Spezia, O and Alduina, R},
title = {Comparison of Antibiotic Resistance Profile and Biofilm Production of Staphylococcus aureus Isolates Derived from Human Specimens and Animal-Derived Samples.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {3},
pages = {},
doi = {10.3390/antibiotics8030097},
pmid = {31330991},
issn = {2079-6382},
support = {Fondo Finalizzato alla Ricerca//Università degli Studi di Palermo/ ; IZS SI 13/15 RC//Italian Ministry of Health/ ; IZS SI 08/16 RC//Italian Ministry of Health/ ; },
abstract = {BACKGROUND: The diffusion of antimicrobial resistance is a significant concern for public health worldwide. Staphylococcus aureus represents a paradigm microorganism for antibiotic resistance in that resistant strains appear within a decade after the introduction of new antibiotics.<br><br>METHODS: Fourteen S. aureus isolates from human specimens and twenty-one from samples of animal origin, were compared for their antimicrobial resistance and biofilm capability. In addition, they were characterized at the molecular level to detect the antimicrobial resistance mecA gene and genes related with enterotoxin, toxin, and biofilm production.<br><br>RESULTS: Both phenotypic and molecular analysis showed main differences among human- and animal-derived isolates. Among the human-derived isolates, more multidrug-resistant isolates were detected and mecA gene, enterotoxin, and toxin genes were more prevalent. Different genes involved in biofilm production were detected with bap present only in animal-derived isolates and sasC present in both isolates, however, with a higher prevalence in the human-derived isolates. Biofilm capability was higher in human-derived isolates mainly associated to the sasC gene.<br><br>CONCLUSIONS: The overall results indicate that human S. aureus isolates are more virulent and resistant than the isolates of animal origin randomly selected with no infection anamnesis. This study confirms that selection for more virulent and resistant S. aureus strains is related to the clinical practice.},
}
@article {pmid31330825,
year = {2019},
author = {Ly, S and Bajoul Kakahi, F and Mith, H and Phat, C and Fifani, B and Kenne, T and Fauconnier, ML and Delvigne, F},
title = {Engineering Synthetic Microbial Communities through a Selective Biofilm Cultivation Device for the Production of Fermented Beverages.},
journal = {Microorganisms},
volume = {7},
number = {7},
pages = {},
doi = {10.3390/microorganisms7070206},
pmid = {31330825},
issn = {2076-2607},
abstract = {Production of Cambodian rice wine involves complex microbial consortia. Indeed, previous studies focused on traditional microbial starters used for this product revealed that three microbial strains with complementary metabolic activities are required for an effective fermentation, i.e., filamentous fungi (Rhizopus oryzae), yeast (Saccharomycescerevisiae), and lactic acid bacteria (Lactobacillusplantarum). Modulating the ratio between these three key players led to significant differences, not only in terms of ethanol and organic acid production, but also on the profile of volatile compounds, in comparison with natural communities. However, we observed that using an equal ratio of spores/cells of the three microbial strains during inoculation led to flavor profile and ethanol yield close to that obtained through the use of natural communities. Compartmentalization of metabolic tasks through the use of a biofilm cultivation device allows further improvement of the whole fermentation process, notably by increasing the amount of key components of the aroma profile of the fermented beverage (i.e., mainly phenylethyl alcohol, isobutyl alcohol, isoamyl alcohol, and 2-methyl-butanol) and reducing the amount of off-flavor compounds. This study is a step forward in our understanding of interkingdom microbial interactions with strong application potential in food biotechnology.},
}
@article {pmid31330262,
year = {2019},
author = {Yu, M and Wang, X and Ling, F and Wang, H and Zhang, P and Shao, S},
title = {Atractylodes lancea volatile oils attenuated helicobacter pylori NCTC11637 growth and biofilm.},
journal = {Microbial pathogenesis},
volume = {135},
number = {},
pages = {103641},
doi = {10.1016/j.micpath.2019.103641},
pmid = {31330262},
issn = {1096-1208},
abstract = {Atractylodes lancea is a traditional Chinese perennial herb, which has been used for treating gastrointestinal diseases in traditional medicine. The aim of this study was to investigate the effect of Atractylodes lancea volatile oils on the planktonic growth and biofilm formation of Helicobacter pylori (H. pylori). Firstly, the minimal inhibitory concentration (MIC) of the volatile oils against H. pylori were determined using broth dilution method. SPSS17.0 was used to account 50% inhibiting concentration (IC50). Moreover, the anti-biofilm activity of the volatile oils was determined by crystal violet measurement and fluorescence microscope. Finally, gastric epithelial cells (GES-1 cells) were co-incubated with H. pylori with or without volatile oils treated. Real-time PCR and western blot were performed to detect the translocation of virulence factor Cag A. We found that Atractylodes lancea volatile oils inhibited the growth of H. pylori in a concentration dependent manner. The MIC and IC50 of volatile oils against H. pylori were 7.5 mg/mL and 2.181 mg/mL respectively. Fluorescence microscopy and crystal violet measurement indicated that volatile oils at sub-MIC concentration could reduce biofilm formation of H. pylori. In addition, volatile oils decreased the translocation of Cag A and reduced inflammatory cytokine IL-8 in GES-1 cells. Our results suggested that Atractylodes lancea volatile oils could be a potential compound of a novel class of H. pylori inhibitors with anti-H. pylori effects.},
}
@article {pmid31329599,
year = {2019},
author = {Lachica, MRCT and Anutrakunchai, C and Prajaneh, S and Nazmi, K and Bolscher, JGM and Taweechaisupapong, S},
title = {Synergistic effects of LFchimera and antibiotic against planktonic and biofilm form of Aggregatibacter actinomycetemcomitans.},
journal = {PloS one},
volume = {14},
number = {7},
pages = {e0217205},
doi = {10.1371/journal.pone.0217205},
pmid = {31329599},
issn = {1932-6203},
abstract = {Adjunctive use of antibiotics in periodontal treatment have limitations and disadvantages including bacterial resistance. Antimicrobial peptides (AMPs) are potential new agents that can combat bacterial infection. In this study, antimicrobial activity of different concentrations of conventional antibiotics minocycline (MH), doxycycline (DOX), and antimicrobial peptides LL-37, LL-31, Lactoferrin chimera (LFchimera) and Innate Defense Regulator Peptide 1018 (IDR-1018) against Aggregatibacter actinomycetemcomitans ATCC 43718 were determined using colony culturing assay. Subsequently, in vitro activity of the most effective drug and peptide combination was evaluated by checkerboard technique. Impact of the drug and peptide co-administration on biofilm at different stages, i.e., during adhesion and 1-day old biofilm was compared to each of the agents used alone. Results revealed that the killing effects of all AMPs range from 13-100%. In contrast, MH and DOX at 1 and 5 μM showed no killing activity and instead stimulated growth of bacteria. DOX has better killing activity than MH. LFchimera displayed the strongest killing amongst the peptides. Checkerboard technique revealed that combining DOX and LFchimera yielded synergism. Confocal laser scanning microscopy further showed that the combination of DOX and LFchimera caused significant reduction of bacterial adhesion and reduction of biomass, average biofilm thickness and substratum biofilm coverage of 1-day old biofilm compared to DOX and LFchimera alone. In conclusion, LFchimera alone and in combination with DOX exhibited strong antibacterial and anti-biofilm property against A. actinomycetemcomitans. The findings suggest that LFchimera should be considered for development as a new potential therapeutic agent that may be used as an adjunctive treatment for periodontitis.},
}
@article {pmid31329200,
year = {2019},
author = {Kwon, HY and Kim, JY and Liu, X and Lee, JY and Yam, JKH and Dahl Hultqvist, L and Xu, W and Rybtke, M and Tolker-Nielsen, T and Heo, W and Kim, JJ and Kang, NY and Joo, T and Yang, L and Park, SJ and Givskov, M and Chang, YT},
title = {Visualizing biofilm by targeting eDNA with long wavelength probe CDr15.},
journal = {Biomaterials science},
volume = {7},
number = {9},
pages = {3594-3598},
doi = {10.1039/c9bm00152b},
pmid = {31329200},
issn = {2047-4849},
abstract = {Detection of the biofilm of bacteria would be a counter strategy to detect hidden bacteria in their camouflage. Through unbiased screening of bacteria biofilm, we discovered a long wavelength probe CDr15 with extracellular DNA as the molecular target. CDr15 revealed a real-time geometric distribution of eDNA in a 3D bacterial colony.},
}
@article {pmid31328358,
year = {2019},
author = {Qiu, H and Pu, F and Liu, Z and Deng, Q and Sun, P and Ren, J and Qu, X},
title = {Depriving Bacterial Adhesion-Related Molecule to Inhibit Biofilm Formation Using CeO2 -Decorated Metal-Organic Frameworks.},
journal = {Small (Weinheim an der Bergstrasse, Germany)},
volume = {15},
number = {36},
pages = {e1902522},
doi = {10.1002/smll.201902522},
pmid = {31328358},
issn = {1613-6829},
support = {21871249//National Natural Science Foundation of China/ ; 21673223//National Natural Science Foundation of China/ ; 21431007//National Natural Science Foundation of China/ ; 21533008//National Natural Science Foundation of China/ ; 21820102009//National Natural Science Foundation of China/ ; //Key Program of Frontier of Sciences/ ; QYZDJ-SSW-SLH052//CAS/ ; },
abstract = {The formation of bacterial biofilm is one of the causes of antimicrobial resistance, often leading to persistent infections and a high fatality rate. Therefore, there is an urgent need to develop novel and effective strategies to inhibit biofilm formation. Adenosine triphosphate (ATP) plays an important role in bacterial adhesion and biofilm formation through stimulating cell lysis and extracellular DNA (eDNA) release. Herein, a simple and robust strategy for inhibiting biofilm formation is developed using CeO2 -decorated porphyrin-based metal-organic frameworks (MOFs). The function of extracellular ATP (eATP) can be inhibited by CeO2 nanoparticles, leading to the disruption of the initial adhesion of bacteria. Furthermore, planktonic bacteria can be killed by cytotoxic reactive oxygen species (ROS) generated by MOFs. As a consequence, the synergic effect of eATP deprivation and ROS generation presents excellent capacity to prevent biofilm formation, which may provide a new direction for designing flexible and effective biofilm-inhibiting systems.},
}
@article {pmid31328252,
year = {2019},
author = {Bazzoli, A and Plateau, J and Turney, A},
title = {Improvement of microbial ecosystem in livestock animal environment: concept of positive biofilm using an example in swine farrowing.},
journal = {Australian veterinary journal},
volume = {97},
number = {9},
pages = {361},
doi = {10.1111/avj.12808},
pmid = {31328252},
issn = {1751-0813},
}
@article {pmid31326562,
year = {2019},
author = {Sowndarya, J and Farisa Banu, S and Madhura, G and Yuvalakshmi, P and Rubini, D and Bandeira Junior, G and Baldisserotto, B and Vadivel, V and Nithyanand, P},
title = {Agro food by-products and essential oil constituents curtail virulence and biofilm of Vibrio harveyi.},
journal = {Microbial pathogenesis},
volume = {135},
number = {},
pages = {103633},
doi = {10.1016/j.micpath.2019.103633},
pmid = {31326562},
issn = {1096-1208},
abstract = {Vibrio harveyi causes severe loss to the aquaculture industry due to its virulence, which is mediated by Quorum sensing (QS) and biofilm formation. In the current study, we have explored the anti-virulent properties and biofilm disruption ability of luteolin (extracted from coconut shell) and linalool against this important aquaculture pathogen. HPLC analysis of the methanolic extract of coconut shells revealed a single major peak which matched to the standard luteolin which was further elucidated by NMR studies. Further, luteolin and linalool were screened for their ability to inhibit biofilms and various quorum sensing mediated virulence factors of V. harveyi. The Minimum Inhibitory Concentration (MIC) of the two compounds was determined and the sub-inhibitory concentrations of the compounds were able to inhibit biofilm formation. Both the compounds disrupted about 60-70% mature biofilms, which was also visually observed by light microscopy. Both linalool and luteolin exhibited a significant reduction in the production of EPS and alginate in the biofilms matrix of V. harveyi which was confirmed by Scanning Electron Microscopy (SEM). Both compounds inhibited the swarming and swimming motility, the crucial quorum sensing (QS) mediated virulence of V. harveyi. The present study shows the presence of valuable polyphenolic compound like luteolin in coconut shells that are discarded as a waste. From the present study we envisage that luteolin and linalool can serve as potent anti-virulent agents to combat QS mediated infections against aquaculture pathogens.},
}
@article {pmid31325779,
year = {2019},
author = {Borah, SN and Sen, S and Goswami, L and Bora, A and Pakshirajan, K and Deka, S},
title = {Rice based distillers dried grains with solubles as a low cost substrate for the production of a novel rhamnolipid biosurfactant having anti-biofilm activity against Candida tropicalis.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {182},
number = {},
pages = {110358},
doi = {10.1016/j.colsurfb.2019.110358},
pmid = {31325779},
issn = {1873-4367},
abstract = {In this study, rhamnolipid (RL) production by Pseudomonas aeruginosa SS14 utilizing rice based Distillers Dried Grains with Solubles (rDDGS) as the sole carbon source was evaluated and the production parameters were optimized using response surface methodology. Highest RL (RL-rDDGS) yield was 14.87 g/L in a culture medium containing 12% (w/v) rDDGS and 11% (v/v) inoculum concentration after 48 h of fermentation at 35 °C. RL-rDDGS was produced as a mixture of mono and di-RL congeners with four novel homologues Rha-C18:2, Rha-C19, Rha-C9, and Rha-Rha-C19. The RL reduced the surface tension of water to 34.8 mN/m at a critical micelle concentration (CMC) value of 100 mg/L, exhibited high stability at a wide range of pH (6-12), heating time (0-120 min), and salinity (2-12% NaCl). Furthermore, RL-rDDGS demonstrated appreciable biofilm disruptive property against Candida tropicalis. This is the first report on the usage of rDDGS for sustainable and low cost production of RL.},
}
@article {pmid31324055,
year = {2019},
author = {Shi, Z and Dittoe, DK and Feye, KM and Kogut, M and Ricke, SC},
title = {Short Communication: Preliminary Differences Identified in Genes Responsible for Biofilm Formation in Poultry Isolates of Salmonella enterica Heidelberg, Enteritidis, and Kentucky.},
journal = {Microorganisms},
volume = {7},
number = {7},
pages = {},
doi = {10.3390/microorganisms7070196},
pmid = {31324055},
issn = {2076-2607},
abstract = {Salmonella enterica is one of the most prevalent foodborne pathogens. The large quantity of serovar types results in the colonization of a large spectrum of hosts, with different environmental conditions and hazards. The aim of this study was to evaluate the differences in gene expression (bcsA and csgD) of Salmonella enterica serovars Heidelberg, Kentucky, and Enteritidis during biofilm formation using quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). Overall, there appeared to be differences in expression between the different serovars with high variation between strains. These data are important as they demonstrate considerable variability in gene expression between serovars and strains of poultry isolates of Salmonella enterica.},
}
@article {pmid31323790,
year = {2019},
author = {Carvalho, DB and Fox, EGP and Santos, DGD and Sousa, JS and Freire, DMG and Nogueira, FCS and Domont, GB and Castilho, LVA and Machado, EA},
title = {Fire Ant Venom Alkaloids Inhibit Biofilm Formation.},
journal = {Toxins},
volume = {11},
number = {7},
pages = {},
doi = {10.3390/toxins11070420},
pmid = {31323790},
issn = {2072-6651},
support = {150895/2010-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; },
abstract = {Biofilm formation on exposed surfaces is a serious issue for the food industry and medical health facilities. There are many proposed strategies to delay, reduce, or even eliminate biofilm formation on surfaces. The present study focuses on the applicability of fire ant venom alkaloids (aka 'solenopsins', from Solenopsis invicta) tested on polystyrene and stainless steel surfaces relative to the adhesion and biofilm-formation by the bacterium Pseudomonas fluorescens. Conditioning with solenopsins demonstrates significant reduction of bacterial adhesion. Inhibition rates were 62.7% on polystyrene and 59.0% on stainless steel surfaces. In addition, solenopsins drastically reduced cell populations already growing on conditioned surfaces. Contrary to assumptions by previous authors, solenopsins tested negative for amphipathic properties, thus understanding the mechanisms behind the observed effects still relies on further investigation.},
}
@article {pmid31323501,
year = {2019},
author = {Morgan-Sagastume, F and Jacobsson, S and Olsson, LE and Carlsson, M and Gyllenhammar, M and Sárvári Horváth, I},
title = {Anaerobic treatment of oil-contaminated wastewater with methane production using anaerobic moving bed biofilm reactors.},
journal = {Water research},
volume = {163},
number = {},
pages = {114851},
doi = {10.1016/j.watres.2019.07.018},
pmid = {31323501},
issn = {1879-2448},
abstract = {Oil-contaminated wastewaters are generally treated by a combination of physico-chemical and biological methods. Interest in the anaerobic treatment of oily wastewaters has increased since it complements aerobic treatment and produces energy in the form of methane. The objectives of this study were to characterise the anaerobic process spontaneously occurring in a full-scale storage tank at a facility treating waste oil and oil-contaminated effluents, and to evaluate the applicability of an anaerobic moving bed biofilm reactor (AnMBBR) and an anaerobic contact reactor (ACR) for treating the oil contaminated wastewater feeding the storage tank. Three lab-scale reactors were operated in parallel over 465 days: one mesophilic and one thermophilic AnMBBR, and one thermophilic ACR. The wastewater had a high strength with an average chemical oxygen demand (COD) of 36 g/L with a soluble fraction of 80%. The BOD7/COD ratios varied between 0.1 and 0.5, indicating low aerobic degradability. However, biomethane potential tests indicated some level of anaerobic degradability with methane yields between 150 and 200 NmL/gCOD. The full-scale storage tank operated at low organic loading rates (0.35-0.43 kgCOD/m3d), and long hydraulic retention times (HRT = 83-104 d). In comparison, the AnMBBRs achieved similar COD reductions (60%) as the full-scale tank but at a much shorter HRT of 30 d. Similar efficiency could only be reached at longer HRTs (43 d) in the ACR due to low biomass levels resulting from poor sludge settleability. The methane yield was higher (210 NmLCH4/COD removed) in the AnMBBR operated at 37 °C, compared to the other reactors working at 50 °C (180 NmLCH4/COD removed). This reactor also maintained a higher COD removal (67%) at an increased OLR of 1.1 kgCOD/m3d than the AnMBBR at 50 °C. The microbial composition of the biomass from the full-scale tank and the laboratory reactors provided evidence for the conversion of oil-contaminated wastewater into methane with a relatively high abundance of hydrogenotrophic methanogens.},
}
@article {pmid31323469,
year = {2019},
author = {Qi, X and Liu, P and Liang, P and Hao, W and Li, M and Huang, X},
title = {Dual-signal-biosensor based on luminescent bacteria biofilm for real-time online alert of Cu(II) shock.},
journal = {Biosensors &amp; bioelectronics},
volume = {142},
number = {},
pages = {111500},
doi = {10.1016/j.bios.2019.111500},
pmid = {31323469},
issn = {1873-4235},
abstract = {The development of real-time online warning system for toxicity materials is important to ensure the safety of water supply. This study for the first time constructs luminescent bacteria (Vibrio fischeri) biofilm to deliver both electrical and optical real-time response for Cu(II) toxic shock in a bioelectrochemical system (BES) sensor. Compared to biocathode, bioanode was more suitable as sensitive elements. With three tested concentrations of Cu(II), i.e., 1 mg/L, 3 mg/L and 6 mg/L, electrical signals were raised. But optical signal failed to respond to the lowest concentration, suggesting that electrical signal then was produced by chemical reaction of Cu(II) on the electrode surface. For 3 mg/L and 6 mg/L Cu(II) shock, more rapid optical signals were observed than electrical signal, indicating that both the biofilm's surface and inner was affected. In addition, high concentration of Cu(II) toxic as 6 mg/L caused irreversible damage in the biosensor as there were great fluctuation in the recovery curve and large recovery ratio up to -10.39% for optical signal. These results provided a comparison between optical and electrical signals simultaneously produced by a biosensor and visual evidences for better understanding of the toxicity process in the biosensor.},
}
@article {pmid31323449,
year = {2019},
author = {Li, D and Chen, S and Dou, H and Wu, W and Liu, Q and Zhang, L and Shen, Y and Shu, G and Yuan, Z and Lin, J and Zhang, W and Peng, G and Zhong, Z and Yin, L and Fu, H},
title = {Preparation of cefquinome sulfate cationic proliposome and evaluation of its efficacy on Staphylococcus aureus biofilm.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {182},
number = {},
pages = {110323},
doi = {10.1016/j.colsurfb.2019.06.053},
pmid = {31323449},
issn = {1873-4367},
abstract = {Staphylococcus aureus (S. aureus) has the propensity to form biofilms, which eventually cause antibiotic resistance and treatment failure. Cefquinome sulfate (CS) is an animal-specific antibacterial agent for S. aureus infection. In this work, CS cationic proliposomes (CSCPs) were prepared by solid-dispersion method combined with effervescent hydration to eradicate bacterial biofilm and improve the antibacterial effect of the drug. CSCPs were readily dispersed in water, thereby forming CS cationic liposomes (CSCLs) as a white, uniform suspension. The CSCLs had an encapsulation efficiency (EE) of 63.21%, a drug loading of 4.04%, an average particle size of 201.5 nm, and a positive zeta-potential of 65.29 mV. In vitro release studies showed that CSCLs had good sustained-release behavior. The CS and CSCL minimal inhibitory concentration (MIC) of S. aureus type culture strain were 1 and 0.48 g/mL, respectively. The eradication effect of CS on bacterial biofilm (BBF) was relatively weak during culture in drug-containing medium for 8 h-24 h. However, the CSCL eradication effect on BBF increased gradually, and the clearance rate of CSCLs on BBF was about twice that of CS. The clearance rate reached 81.30% with 2.5 × MIC in 24 h. All these results indicated that CSCLs can significantly improve the eradication effect of cefquinome on biofilm to inhibit bacterial growth.},
}
@article {pmid31323072,
year = {2019},
author = {, },
title = {Correction: Circuit diversification in a biofilm regulatory network.},
journal = {PLoS pathogens},
volume = {15},
number = {7},
pages = {e1007966},
doi = {10.1371/journal.ppat.1007966},
pmid = {31323072},
issn = {1553-7374},
abstract = {[This corrects the article DOI: 10.1371/journal.ppat.1007787.].},
}
@article {pmid31321751,
year = {2019},
author = {Černáková, L and Light, C and Salehi, B and Rogel-Castillo, C and Victoriano, M and Martorell, M and Sharifi-Rad, J and Martins, N and Rodrigues, CF},
title = {Novel Therapies for Biofilm-Based Candida spp. Infections.},
journal = {Advances in experimental medicine and biology},
volume = {},
number = {},
pages = {},
doi = {10.1007/5584_2019_400},
pmid = {31321751},
issn = {0065-2598},
abstract = {The presence of fungal infections continue to grow worldwide, mostly in immunosuppressed patients, and in individuals with continued antimicrobial treatments. Candida spp. are the most common yeasts involved in these disorders, being associated with a high rate of antifungal resistance and an increased ability to form biofilms, which make the treatment of these infections difficult. This review aims to present and discuss the main biofilm-related infections cause by several Candida spp. and novel therapies that are currently available in the clinical, scientific and academic environment. New drugs with promising antifungal activity, natural approaches (e.g. probiotics, essential oils, plant extracts, honey) and a final consideration on alternative methodologies, such as photodynamic therapy are presented and discussed.},
}
@article {pmid31321337,
year = {2019},
author = {Pakshir, K and Sheykhi, S and Zomorodian, K and Nouraei, H and Zare Shahrabadi, Z},
title = {Evaluation of biofilm formation in the homozygous and heterozygous strains of vaginal Candida albicans isolates.},
journal = {Current medical mycology},
volume = {5},
number = {2},
pages = {37-40},
doi = {10.18502/cmm.5.2.1160},
pmid = {31321337},
issn = {2423-3439},
abstract = {Background and Purpose: Candida albicans is one of the most opportunistic yeasts around the world. This species has two heterozygous and homozygous strains at hyphal wall protein 1 (hwp1) gene locus. A simple method for the discrimination of these two strains is the amplification of HWP1 gene. Regarding this, the aim of this study was to discriminate C. albicans heterozygous and homozygous strains via the amplification of hwp1 gene and evaluation of biofilm formation between the strains.<br><br>Materials and Methods: A total of 60 homozygous (n=30) and heterozygous (n=30) strains were discriminated among 126 C. albicans vaginal isolates by the amplification of HWP1 gene, using specific primers. The evaluation of biofilm formation was accomplished using the visual method.<br><br>Results: According to the results, the homozygous and heterozygous strains produced one and two DNA fragments, respectively. The frequency of homozygous strains among the C. albicans vaginal isolates was 76.2%. Biofilm formation activity in the heterozygous strains was more than that in the homozygous strains. However, statistical analysis showed no significant difference between the strains in terms of biofilm formation.<br><br>Conclusion: As the findings indicated, the frequency of the heterozygous strains in C. albicans was lower than that of the homozygous strains. Both of the strains could form biofilm in the different ranges of severity. High activity of biofilm formation in heterozygous strains may set the ground for its pathogenicity.},
}
@article {pmid31320183,
year = {2019},
author = {Lee, MJ and Kwon, JS and Kim, JY and Ryu, JH and Seo, JY and Jang, S and Kim, KM and Hwang, CJ and Choi, SH},
title = {Bioactive resin-based composite with surface pre-reacted glass-ionomer filler and zwitterionic material to prevent the formation of multi-species biofilm.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {35},
number = {9},
pages = {1331-1341},
doi = {10.1016/j.dental.2019.06.004},
pmid = {31320183},
issn = {1879-0097},
abstract = {OBJECTIVE: This study evaluated the synergetic effect between surface pre-reacted glass-ionomer (SPRG) filler and 2-methacryloyloxyethyl phosphorylcholine (MPC), for inhibiting multi-species biofilm formation, while maintaining or even improving the original beneficial features of SPRG-filled resin-based composite (RBC).<br><br>METHODS: MPC (1.5-10wt%) was incorporated into commercial SPRG-filled RBC. Then, the inherent properties of RBC, and ion release and acid-neutralising properties associated with SPRG were investigated. Further, protein adsorptions and bacterial adhesion and viability on the SPRG-filled RBC surfaces were studied using four kinds of oral bacteria; Streptococcus mutans, Actinomyces naeslundii, Veillonella parvula, and Porphyromonas gingivalis. Finally, the thickness and biomass of the human saliva-derived biofilm model cultured on test and control samples were analysed.<br><br>RESULTS: Addition of MPC content resulted in decreased flexural strength and wettability of SPRG-filled RBC. SPRG-filled RBC released significantly higher amounts of multiple ions as contents of MPC increased. Meanwhile, SPRG-filled RBC with 5-wt% MPC significantly improved acid-neutralising properties than those of other test and control samples (P<0.001). SPRG-filled RBC with 3wt% MPC significantly reduced the amount of adsorbed bovine serum albumin and proteins from the brain heart infusion medium as compared to the control (P<0.01). A similar trend was observed in the attachment of four types of bacteria and multi-species biofilm (P<0.01).<br><br>SIGNIFICANCE: Despite limitation in terms of deteriorations of some physical properties, addition of 3% MPC to SPRG-filled RBC leads to inhibition of the attachment of multi-species bacteria on its surface, as well as inhibition of biofilm growth. Moreover, the original important bioactive features of SPRG-filled RBC such as ion release and acid neutralisations are either maintained or improved upon adding MPC.},
}
@article {pmid31319827,
year = {2019},
author = {Ahmed, AA and Salih, FA},
title = {Quercus infectoria gall extracts reduce quorum sensing-controlled virulence factors production and biofilm formation in Pseudomonas aeruginosa recovered from burn wounds.},
journal = {BMC complementary and alternative medicine},
volume = {19},
number = {1},
pages = {177},
doi = {10.1186/s12906-019-2594-5},
pmid = {31319827},
issn = {1472-6882},
abstract = {BACKGROUND: Quercus gall extracts' ability to kill pathogens in vitro and even removal of chronic drug-resistant infections has been reported by several studies. The current investigation is focused on the action of extracts of Quercus infectoria gall in their sub-inhibitory concentrations on the corresponding bacterial behaviours instead of killing them.<br><br>METHODS: The effect of gall extracts on the quorum sensing (QS) associated virulence of multiple drug resistant Pseudomonas aeruginosa recovered from burns wounds was studied. The influence of different extracts on the production of bacterial virulence and biofilm, and expression of the genes encoding quorum sensing and exotoxin A were investigated. Quorum sensing is a crucial regulator of virulence and biofilm development in Pseudomonas aeruginosa and other medical related microbes.<br><br>RESULTS: Experiments to characterise and quantify Q. infectoria gall extracts impact on the quorum sensing networks of P.aeruginosa revealed that the expression of las, rhl, and exotoxin A (ETA) genes levels including the associated virulence were reduced by the extracts at their subinhibitory concentrations.<br><br>CONCLUSIONS: The obtained results indicated that extracts of Q. infectoria galls fight infections either by their inhibitory constituents, which vigorously eradicate cells or by disruption of the pathogens quorum sensing system through weakening the virulence and bacterial coordination.},
}
@article {pmid31319670,
year = {2019},
author = {Balasubramanian, S and Aubin-Tam, ME and Meyer, AS},
title = {3D Printing for the Fabrication of Biofilm-Based Functional Living Materials.},
journal = {ACS synthetic biology},
volume = {8},
number = {7},
pages = {1564-1567},
doi = {10.1021/acssynbio.9b00192},
pmid = {31319670},
issn = {2161-5063},
abstract = {Bacterial biofilms are three-dimensional networks of cells entangled in a self-generated extracellular polymeric matrix composed of proteins, lipids, polysaccharides, and nucleic acids. Biofilms can establish themselves on virtually any accessible surface and lead to varying impacts ranging from infectious diseases to degradation of toxic chemicals. Biofilms exhibit high mechanical stiffness and are inherently tolerant to adverse conditions including the presence of antibiotics, pollutants, detergents, high temperature, changes in pH, etc. These features make biofilms resilient, which is beneficial for applications in dynamic environments such as bioleaching, bioremediation, materials production, and wastewater purification. We have recently described an easy and cost-effective method for 3D printing of bacteria and have extended this technology for 3D printing of genetically engineered Escherichia coli biofilms. Our 3D printing platform exploits simple alginate chemistry for printing of a bacteria-alginate bioink mixture onto calcium-containing agar surfaces, resulting in the formation of bacteria-encapsulating hydrogels with varying geometries. Bacteria in these hydrogels remain intact, spatially patterned, and viable for several days. Printing of engineered bacteria to produce inducible biofilms leads to formation of multilayered three-dimensional structures that can tolerate harsh chemical treatments. Synthetic biology and material science approaches provide the opportunity to append a wide range of useful functionalities to these 3D-printed biofilms. In this article, we describe the wide range of future applications possible for applying functional 3D-printed biofilms to the construction of living biofilm-derived materials in a large-scale and environmentally stable manner.},
}
@article {pmid31319057,
year = {2019},
author = {Narayana, JL and Mishra, B and Lushnikova, T and Golla, RM and Wang, G},
title = {Modulation of antimicrobial potency of human cathelicidin peptides against the ESKAPE pathogens and in vivo efficacy in a murine catheter-associated biofilm model.},
journal = {Biochimica et biophysica acta. Biomembranes},
volume = {1861},
number = {9},
pages = {1592-1602},
doi = {10.1016/j.bbamem.2019.07.012},
pmid = {31319057},
issn = {1879-2642},
support = {R01 AI105147/AI/NIAID NIH HHS/United States ; R56 AI105147/AI/NIAID NIH HHS/United States ; },
abstract = {Antimicrobial peptides are essential components of innate immune systems that protect hosts from infection. They are also useful candidates for developing a new generation of antibiotics to fight antibiotic-resistant pathogens. Human innate immune peptide LL-37 can inhibit biofilm formation, but suffers from high cost due to a long peptide length and rapid protease degradation. To improve the peptide, we previously identified the major active region and changed the peptide backbone structure. This study designed two families of new peptides by altering peptide side chains. Interestingly, these peptides displayed differential potency against various ESKAPE pathogens in vitro and substantially reduced hemolysis. Further potency test in vivo revealed that 17tF-W eliminated the burden of methicillin-resistant Staphylococcus aureus (MRSA) USA300 in both mouse-embedded catheters and their surrounding tissues. In addition, peptide treatment suppressed the level of chemokine TNFα, and boosted the levels of chemokines MCP-1, IL-17A and IL-10 in the surrounding tissues of the infected catheter embedded in mice. In conclusion, we have designed a set of new LL-37 peptides with varying antimicrobial activities, opening the door to potential topical treatment of infections involving different drug-resistant pathogens.},
}
@article {pmid31318574,
year = {2019},
author = {Patel, KK and Surekha, DB and Tripathi, M and Anjum, MM and Muthu, MS and Tilak, R and Agrawal, AK and Singh, S},
title = {Antibiofilm Potential of Silver Sulfadiazine-Loaded Nanoparticle Formulations: A Study on the Effect of DNase-I on Microbial Biofilm and Wound Healing Activity.},
journal = {Molecular pharmaceutics},
volume = {16},
number = {9},
pages = {3916-3925},
doi = {10.1021/acs.molpharmaceut.9b00527},
pmid = {31318574},
issn = {1543-8392},
abstract = {Biofilm resistance is one of the severe complications associated with chronic wound infections, which impose extreme microbial tolerance against antibiotic therapy. Interestingly, deoxyribonuclease-I (DNase-I) has been empirically proved to be efficacious in improving the antibiotic susceptibility against biofilm-associated infections. DNase-I hydrolyzes the extracellular DNA, a key component of the biofilm responsible for the cell adhesion and strength. Moreover, silver sulfadiazine, a frontline therapy in burn wound infections, exhibits delayed wound healing due to fibroblast toxicity. In this study, a chitosan gel loaded with solid lipid nanoparticles of silver sulfadiazine (SSD-SLNs) and supplemented with DNase-I has been developed to reduce the fibroblast cytotoxicity and overcome the biofilm-imposed resistance. The extensive optimization using the Box-Behnken design (BBD) resulted in the formation of SSD-SLNs with a smooth surface as confirmed by scanning electron microscopy and controlled release (83%) for up to 24 h. The compatibility between the SSD and other formulation excipients was confirmed by Fourier transform infrared, differential scanning calorimetry, and powder X-ray diffraction studies. Developed SSD-SLNs in combination with DNase-I inhibited around 96.8% of biofilm of Pseudomonas aeruginosa as compared to SSD with DNase-I (82.9%). In line with our hypothesis, SSD-SLNs were found to be less toxic (cell viability 90.3 ± 3.8% at 100 μg/mL) in comparison with SSD (Cell viability 76.9 ± 4.2%) against human dermal fibroblast cell line. Eventually, the results of the in vivo wound healing study showed complete wound healing after 21 days' treatment with SSD-SLNs along with DNase-I, whereas marketed formulations SSD and SSD-LSNs showed incomplete healing after 21 days. Data in hand suggest that the combination of SSD-SLNs with DNase-I is an effective treatment strategy against the biofilm-associated wound infections and accelerates wound healing.},
}
@article {pmid31318043,
year = {2019},
author = {Alsahhaf, A and Al-Aali, KA and Alshagroud, RS and Alshiddi, IF and Alrahlah, A and Abduljabbar, T and Javed, F and Vohra, F},
title = {Comparison of yeasts species in the subgingival oral biofilm of type 2-diabetic and non-diabetic individuals with peri-implantitis.},
journal = {Journal of periodontology},
volume = {},
number = {},
pages = {},
doi = {10.1002/JPER.19-0091},
pmid = {31318043},
issn = {1943-3670},
abstract = {BACKGROUND: There are no studies that have investigated the presence of yeasts in the subgingival oral biofilm (OB) of type-2 diabetic and non-diabetic patients with peri-implantitis. The aim was to assess the presence of yeasts in the subgingival OB of type-2 diabetic and non-diabetic patients with peri-implantitis.<br><br>MATERIALS AND METHODS: Type-2 diabetic individuals with peri-implantitis (Group-A), non-diabetic individuals with peri-implantitis (Group-B) and non-diabetic individuals without peri-implantitis (Group-C) were included. Life style related and demographic data was collected using a questionnaire and hemoglobin A1c levels were measured. Peri-implant plaque-index (PI), bleeding-on-probing (BOP) and probing-depth (PD) were evaluated and crestal bone loss (CBL) were measured. Subgingival OB samples were collected, and oral yeasts species were identified using ChromAgar medium. Level of significance was set at P < 0.05.<br><br>RESULTS: The mean age of individuals in groups A (n = 43), B (n = 41) and C (n = 42) were 55.6 ± 6.4, 54.6 ± 4.5 and 57.1 ± 3.3 years, respectively. The mean HbA1c levels were higher in Group-A (P < 0.01) than groups B and C. Peri-implant PI (P < 0.01), BOP (P < 0.01), PD (P < 0.01) and CBL (P < 0.01) were significantly higher in Group-A compared with patients in groups B and C. Peri-implant PI (P < 0.05), BOP (P < 0.05), PD (P < 0.05) and CBL (P < 0.05) were significantly higher among patients in Group-B compared with Group-C. Subgingival yeasts were more often isolated from the OB of patients in groups A (74.4%) and B (46.3%) than Group-C (7.1%). The most common yeast species identified in all groups was Candida albicans (C. albicans). The CFU/ml for subgingival yeasts were higher in Group-A than groups B (P < 0.01) and C (P < 0.01). The CFU/ml for subgingival yeasts were higher in Group-B than Group-C (P < 0.01).<br><br>CONCLUSION: Candida species (predominantly C. albicans) were more often present in the subgingival OB of type-2 diabetic and non-diabetic patients with peri-implantitis than systemically healthy individuals without peri-implant diseases. This article is protected by copyright. All rights reserved.},
}
@article {pmid31315967,
year = {2019},
author = {Sherman, E and Bayles, K and Moormeier, D and Endres, J and Wei, T},
title = {Observations of Shear Stress Effects on Staphylococcus aureus Biofilm Formation.},
journal = {mSphere},
volume = {4},
number = {4},
pages = {},
doi = {10.1128/mSphere.00372-19},
pmid = {31315967},
issn = {2379-5042},
abstract = {Staphylococcus aureus bacteria form biofilms and distinctive microcolony or &quot;tower&quot; structures that facilitate their ability to tolerate antibiotic treatment and to spread within the human body. The formation of microcolonies, which break off, get carried downstream, and serve to initiate biofilms in other parts of the body, is of particular interest here. It is known that flow conditions play a role in the development, dispersion, and propagation of biofilms in general. The influence of flow on microcolony formation and, ultimately, what factors lead to microcolony development are, however, not well understood. The hypothesis being examined is that microcolony structures form within a specific range of levels of shear stress. In this study, laminar shear flow over a range of 0.15 to 1.5 dynes/cm2 was examined. It was found that microcolony structures form in a narrow range of shear stresses around 0.6 dynes/cm2 Further, measurements of cell density as a function of space and time showed that shear dependence can be observed hours before microcolonies form. This is significant because, among other physiologic flows, this is the same shear stress found in large veins in the human vasculature, which, along with catheters of similar diameters and flow rates, may therefore play a critical role in biofilm development and subsequent spreading of infections throughout the body.IMPORTANCE It is well known that flow plays an important role in the formation, transportation, and dispersion of Staphylococcus aureus biofilms. What was heretofore not known was that the formation of tower structures in these biofilms is strongly shear stress dependent; there is, in fact, a narrow range of shear stresses in which the phenomenon occurs. This work quantifies the observed shear dependence in terms of cell growth, distribution, and fluid mechanics. It represents an important first step in opening up a line of questioning as to the interaction of fluid forces and their influence on the dynamics of tower formation, break-off, and transportation in biofilms by identifying the parameter space in which this phenomenon occurs. We have also introduced state-of-the-art flow measurement techniques to address this problem.},
}
@article {pmid31315572,
year = {2019},
author = {Zeighami, H and Valadkhani, F and Shapouri, R and Samadi, E and Haghi, F},
title = {Virulence characteristics of multidrug resistant biofilm forming Acinetobacter baumannii isolated from intensive care unit patients.},
journal = {BMC infectious diseases},
volume = {19},
number = {1},
pages = {629},
doi = {10.1186/s12879-019-4272-0},
pmid = {31315572},
issn = {1471-2334},
abstract = {BACKGROUND: Nosocomial infections and persistence of multidrug resistant biofilm forming Acinetobacter baumannii in hospitals has made it as a serious problem in healthcare settings worldwide.<br><br>METHODS: A total of 100 A. baumannii clinical isolates from immunocompromised patients hospitalized in ICU were investigated for biofilm formation, the presence of biofilm related genes (bap, ompA, csuE, fimH, epsA, blaPER-1, bfmS, ptk, pgaB, csgA, kpsMII), integron characterization and molecular typing based on REP-PCR.<br><br>RESULTS: All isolates were resistant to three or more categories of antibiotics and considered as multidrug resistant (MDR). A total of 32 isolates were resistant to all tested antibiotics and 91% were extensively drug-resistance (XDR). All isolates were able to produce biofilm and 58% of isolates showed strong ability to biofilm formation. All strong biofilm forming A. baumannii isolates were XDR. All A. baumannii isolates carried at least one biofilm related gene. The most prevalent gene was csuE (100%), followed by pgaB (98%), epsA and ptk (95%), bfmS (92%) and ompA (81%). 98% of isolates carried more than 4 biofilm related genes, simultaneously. Class I integron (67%) was more frequent in comparison with class II (10%) (P < 0.05). The REP-PCR patterns were classified as 8 types (A-H) and 21 subtypes. The A1 (23%) and C1 (15%) clusters were the most prevalent among A. baumannii isolates (P < 0.05). According to the REP-PCR patterns, 23% of all isolates had a clonal relatedness.<br><br>CONCLUSION: Our study revealed the high frequency of biofilm forming XDR A. baumannii in ICU patients, with a high prevalence of biofilm related genes of csuE and pgaB. It seems that the appropriate surveillance and control measures are essential to prevent the emergence and transmission of XDR A. baumannii in our country.},
}
@article {pmid31314663,
year = {2019},
author = {Sianglum, W and Muangngam, K and Joycharat, N and Voravuthikunchai, SP},
title = {Mechanism of Action and Biofilm Inhibitory Activity of Lupinifolin Against Multidrug-Resistant Enterococcal Clinical Isolates.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2018.0391},
pmid = {31314663},
issn = {1931-8448},
abstract = {The treatment of enterococcal infections is becoming more difficult because of multidrug resistance (MDR). Lupinifolin, a prenylated flavonoid isolated from Albizia myriophylla Benth., showed a potent antimicrobial activity against enterococci. The aim of this study was to investigate antibacterial activity and action of lupinifolin against MDR enterococcal clinical isolates. Antibacterial properties of lupinifolin against 21 MDR isolates were assessed using broth microdilution method and time-kill assay. To study mode of action of lupinifolin on the isolates, propidium iodide intensity, salt tolerance assay, and electron microscopic analyses were performed. Antibiofilm formation activity of lupinifolin was conducted using crytal violet assay. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration values of lupinifolin against the isolates ranged between 0.5 and 2.0 μg/mL and between 2 and 16 μg/mL, respectively. Lupinifolin at 2MIC and 4MIC inhibited the bacterial growth >2 log colony-forming units (CFU)/mL at 2 hr incubation by time-kill analysis. The compound increased membrane permeability and caused loss of salt tolerance. SEM and TEM micrographs revealed pronounced morphological and ultrastructural changes in the treated bacteria. Crystal violet staining showed the antibiofilm-producing activity of lupinifolin against four MDR enterococci. This study suggested that lupinifolin is an essential antimicrobial agent that could be useful for the treatment of MDR enterococcal infections.},
}
@article {pmid31313963,
year = {2019},
author = {Khelissa, SO and Abdallah, M and Jama, C and Barras, A and Chihib, NE},
title = {Comparative Study on the Impact of Growth Conditions on the Physiology and the Virulence of Pseudomonas aeruginosa Biofilm and Planktonic Cells.},
journal = {Journal of food protection},
volume = {82},
number = {8},
pages = {1357-1363},
doi = {10.4315/0362-028X.JFP-18-565},
pmid = {31313963},
issn = {1944-9097},
abstract = {The aim of the present work was to study and compare the effect of growth temperature (20, 30, and 37°C) and surface type (stainless steel and polycarbonate) on the production of virulence factors, such as proteases and siderophores, and the risk of surface contamination associated with Pseudomonas aeruginosa biofilm and planktonic cells. The increase of growth temperature from 20 to 37°C increased (approximately twofold) the electronegative charge and the hydrophobicity of the P. aeruginosa biofilm cell surface. P. aeruginosa biofilm cell adhesion to stainless steel and polycarbonate was 5- and 1.5-fold higher than their planktonic counterparts at 20 and 30°C, respectively. The increase of growth temperature from 20 to 37°C increased the production of proteases (twofold) and siderophores (twofold) and the cytotoxicity (up to 30-fold) against the HeLa cell line in the supernatants of P. aeruginosa planktonic and biofilm cultures. This study also highlighted that biofilm and planktonic P. aeruginosa cells exhibited distinct physiological properties with respect to the production of virulence factors and the cytotoxicity against the Hela cell line. Therefore, effective disinfection procedures should be adapted to inactivate bacteria detached from biofilms.},
}
@article {pmid31312343,
year = {2019},
author = {Wei, Q and Zhang, Z and Luo, J and Kong, J and Ding, Y and Chen, Y and Wang, K},
title = {Insulin treatment enhances pseudomonas aeruginosa biofilm formation by increasing intracellular cyclic di-GMP levels, leading to chronic wound infection and delayed wound healing.},
journal = {American journal of translational research},
volume = {11},
number = {6},
pages = {3261-3279},
pmid = {31312343},
issn = {1943-8141},
abstract = {Diabetes-related infections have become challenging and important public health problems in China and around the world. P. aeruginosa plays an important role in diabetic foot infections. As a gram-negative opportunistic pathogen, P. aeruginosa causes recurrent and refractory infections that are characterized by biofilm formation. Previous studies have demonstrated that biofilm-challenged wounds typically take longer to heal than non-biofilm-challenged normal wounds in diabetic mouse models. In the present study, we sought to explore the mechanism via which insulin treatment affects cyclic di-GMP signaling in P. aeruginosa-infected chronic wounds in db/db diabetic mice. We found that the wounds of diabetic mice healed more slowly than those of nondiabetic mice. Moreover, wound healing in diabetic mice treated with insulin exhibited a considerable delay. Peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) was used to detect biofilms on P. aeruginosa-infected wound tissues. Increased intracellular c-di-GMP levels promoted biofilm formation in wound tissues from nondiabetic mice. Greater biofilm formation was observed in the wounds of insulin-treated diabetic mice than in the wounds of untreated diabetic mice or nondiabetic mice, in both the PAO1/plac-yhjH- and PAO1-infected groups. Quantitative RT-PCR indicated that upon infection with PAO1/Plac-yhjH (the low c-di-GMP expression strain), the expression of IL-4 RNA was significantly higher in diabetic mice treated with insulin than in untreated diabetic mice or nondiabetic mice at each observation time point. Peak expression of IFN-γ occurred earlier in diabetic mice treated with insulin than in untreated diabetic mice with each of the experimental strains. Finally, P. aeruginosa harboring the plasmid pCdrA: gfps was used as a reporter strain to monitor c-di-GMP levels. We found that insulin could promote biofilm formation by increasing intracellular c-di-GMP levels in vitro. Taken together, these data demonstrate that insulin treatment increases intracellular c-di-GMP levels, promotes biofilm formation and prolongs the inflammation period during the healing of infected wounds, resulting in delayed wound healing.},
}
@article {pmid31311139,
year = {2019},
author = {Nóbrega, V and Faria, M and Quintana, A and Kaufmann, M and Ferreira, A and Cordeiro, N},
title = {From a Basic Microalga and an Acetic Acid Bacterium Cellulose Producer to a Living Symbiotic Biofilm.},
journal = {Materials (Basel, Switzerland)},
volume = {12},
number = {14},
pages = {},
doi = {10.3390/ma12142275},
pmid = {31311139},
issn = {1996-1944},
support = {REBECA (MAC/1.1a/060)//European Territorial Cooperation Programme PCT-MAC 2014-2020/ ; M1420-01-0145-FEDER-000001//Oceanic Observatory of Madeira/ ; },
abstract = {Bacterial cellulose (BC) has recently been the subject of a considerable amount of research, not only for its environmentally friendly biosynthesis, but also for its high potential in areas such as biomedicine or biomaterials. A symbiotic relationship between a photosynthetic microalga, Chlamydomonas debaryana, and a cellulose producer bacterium, Komagataeibacter saccharivorans, was established in order to obtain a viable and active biofilm. The effect of the growth media composition ratio on the produced living material was investigated, as well as the microalgae biomass quantity, temperature, and incubation time. The optimal temperature for higher symbiotic biofilm production was 30 °C with an incubation period of 14 days. The high microalgae presence, 0.75% w/v, and 60:40 HS:BG-11 medium (v/v) induced a biofilm microalgae incorporation rate of 85%. The obtained results report, for the first time, a successful symbiotic interaction developed in situ between an alkaline photosynthetic microalga and an acetic acid bacterium. These results are promising and open a new window to BC living biofilm applications in medical fields that have not yet been explored.},
}
@article {pmid31310825,
year = {2019},
author = {Cusicanqui Méndez, DA and Gutierrez, E and Campos Chaves Lamarque, G and Lopes Rizzato, V and Afonso Rabelo Buzalaf, M and Andrade Moreira Machado, MA and Cruvinel, T},
title = {The effectiveness of curcumin-mediated antimicrobial photodynamic therapy depends on pre-irradiation and biofilm growth times.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {27},
number = {},
pages = {474-480},
doi = {10.1016/j.pdpdt.2019.07.011},
pmid = {31310825},
issn = {1873-1597},
abstract = {BACKGROUND: The aim of this study was to determine the influence of distinct pre-irradiation times (PIT) of curcumin on the effectiveness of antimicrobial photodynamic therapy (aPDT) against intact dentin caries biofilms grown for 3 or 5 days.<br><br>METHODS: The microcosm biofilms grew on non-fluorescent glass blocks immersed in McBain medium with 1% sucrose, using microaerophilic conditions at 37 °C for 3 or 5 days. The biofilms were treated by the association of 600 μmol.L-1 curcumin using different pre-irradiation times (1, 2 or 5 min) combined with 0 or 75 J.cm-2 blue LED. Then, the vitality of biofilms was determined by confocal scanning laser microscopy (CSLM), after being stained with the mixture of ethidium bromide and fluorescein diacetate. Statistical analysis was performed by two-way ANOVA and post-hoc Tukey tests, after arcsine transformation (P < 0,05).<br><br>RESULTS: In comparison to control, curcumin alone (PIT = 5 min) and all combinations of curcumin and LED reduced significantly the vitality of 3-day biofilms. Distinctly, only curcumin plus LED using PITs of 2 or 5 min were effective in reducing the vitality of 5-day biofilms.<br><br>CONCLUSION: Curcumin-mediated aPDT significantly decreased the vitality of intact dentin caries microcosms grown during 3 or 5 days, although successful treatments of 5-day biofilms required longer PITs in comparison to their counterparts.},
}
@article {pmid31303882,
year = {2019},
author = {Bahari, M and Ebrahimi Chaharom, ME and Daneshpooy, M and Gholizadeh, S and Pashayi, H},
title = {Effect of bleaching protocols on surface roughness and biofilm formation on silorane-based composite resin.},
journal = {Dental research journal},
volume = {16},
number = {4},
pages = {264-270},
pmid = {31303882},
issn = {1735-3327},
abstract = {Background: Knowledge about the effect of bleaching on behavior of composite resins is important to find a suitable composite resin for restoration of teeth undergoing bleaching. This study aimed to assess the effect of different bleaching protocols on surface roughness and biofilm formation on a silorane-based composite resin.<br><br>Materials and Methods: In this in vitro experimental study, 60 silorane-based composite resin samples measuring 3 mm in thickness and 6 mm in diameter were fabricated and polished. They were then randomly divided into four groups (n = 15). In Group 1, samples were stored in distilled water as control. Samples in Groups 2, 3, and 4 were subjected to bleaching with 15% carbamide peroxide, 35% hydrogen peroxide, and 35% hydrogen peroxide activated by light, respectively. Surface roughness was measured using a profilometer. Streptococcus mutans cultured in brain-heart infusion broth was used for the assessment of biofilm formation on the samples. The bacterial colonies were counted using the pure-plate technique. Data were analyzed using one-way ANOVA and post hoc Tukey's tests. Regression model was used to assess the association between surface roughness and biofilm formation (P < 0.05).<br><br>Results: The mean surface roughness of the four groups was not significantly different (P = 0.11); however, a significant difference was noted in the mean biofilm formation among the groups (P = 0.00).<br><br>Conclusion: Bleaching decreased biofilm formation. The lowest biofilm formation was noted in the group subjected to light-activated 35% hydrogen peroxide. Increased surface roughness enhanced biofilm formation to a certain level; excessive roughness did not increase biofilm formation.},
}
@article {pmid31303772,
year = {2019},
author = {Farajzadeh Sheikh, A and Asareh Zadegan Dezfuli, A and Navidifar, T and Fard, SS and Dehdashtian, M},
title = {Association between biofilm formation, structure and antibiotic resistance in Staphylococcus epidermidis isolated from neonatal septicemia in southwest Iran.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {1771-1782},
doi = {10.2147/IDR.S204432},
pmid = {31303772},
issn = {1178-6973},
abstract = {Background:Staphylococcus epidermidis has emerged as the pathogen from neonatal septicemia. Antibiotic resistance and the capability of biofilm formation make these infections much harder to treat. Hence, the aim of this study was to investigate the association between biofilm formation, structure and antibiotic resistance in S. epidermidis isolated from neonatal septicemia. Methods: Overall, 65 S. epidermidis isolates were recovered from blood cultures of neonatal septicemia. Antibiotic resistance pattern and the biofilm production were determined using phenotypic methods. The presence of ica operon, the bhp, the aap genes and SCCmec types were screened using PCR. Results: Most S.epidermidis isolates were resistant to erythromycin, while all isolates were sensitive to linezolid and vancomycin. Fifty-three percent of S.epidermidis isolates were resistant to methicillin. SCCmec types II was found commonly among methicillin-resistant S. epidermidis (MRSE) strains. The biofilm formation was observed in 65% of S.epidermidis isolates and the majority have polysaccharide matrix. icaA and icaD genes were found in 40% and 19% of isolates. Twenty-three isolates (62%) produced dissolvable polysaccharide intercellular adhesion (PIA)-dependent biofilms in SM after growth in TSB with NaCl and 14 (37%) isolates produced dissolvable protein-dependent biofilms in PK after growth in TSB with glucose. Three isolates (62%) produced dissolvable polysaccharide intercellular adhesion. Conclusion: Our data indicate the high rates of antibiotic resistance and the capability of biofilm formation among S. epidermidis isolates. Hence, the transmission of these strains can cause an increased risk of serious nosocomial infections.},
}
@article {pmid31302463,
year = {2019},
author = {Zhang, Q and Zhang, L and Li, Z and Zhang, L and Li, D},
title = {Enhancement of fipronil degradation with eliminating its toxicity in a microbial fuel cell and the catabolic versatility of anodic biofilm.},
journal = {Bioresource technology},
volume = {290},
number = {},
pages = {121723},
doi = {10.1016/j.biortech.2019.121723},
pmid = {31302463},
issn = {1873-2976},
abstract = {The degradation of fipronil was investigated in microbial fuel cells (MFCs). Almost 79% of 30 mg/L fipronil was rapidly degraded within 12 h by MFC biofilm. Based on the constructed quadratic polynomial model, a maximum fipronil degradation rate of 94.22% could be theoretically achieved at pH of 7.01, 33.39 °C, and the initial fipronil concentration 74 mg/L after incubation for 72 h. The high acute toxicity of fipronil toward zebrafish was largely eliminated after degradation by the MFC. In addition, the MFC biofilm showed catabolic versatility to 4-chloronitrobenzene, sulfanilamide, fluoroglycofen, and azoxystrobin. The microbial community analysis revealed that the functional bacteria Sphaerochaeta, Pseudomonas, Azospirillum, Azoarcus, and Chryseobacterium were major predominant bacteria in the anodic biofilm. Therefore, the MFC offers a promising approach in treating the environmental contaminants due to its abilities of energy capture from waste substances and catabolic versatility to different organic compounds.},
}
@article {pmid31300852,
year = {2019},
author = {Zara, G and Bou Zeidan, M and Fancello, F and Sanna, ML and Mannazzu, I and Budroni, M and Zara, S},
title = {The administration of L-cysteine and L-arginine inhibits biofilm formation in wild-type biofilm-forming yeast by modulating FLO11 gene expression.},
journal = {Applied microbiology and biotechnology},
volume = {103},
number = {18},
pages = {7675-7685},
doi = {10.1007/s00253-019-09996-5},
pmid = {31300852},
issn = {1432-0614},
abstract = {Microbial biofilms are undesired in food manufacturing, drinking water distribution systems, and clinical realms. Yeast biofilms are particularly problematic because of the strong capacity of yeast cells to adhere to abiotic surfaces, cells, and tissues. Novel approaches have been developed over recent years to prevent the establishment of microbial biofilms, such as through the use of small molecules with inhibiting and dispersing properties. Here, we studied the inhibitory activity of 11 different amino acids on the biofilm formation ability of three wild-type Saccharomyces cerevisiae strains and the reference strain ∑1278b. Subsequent evaluation of different concentrations of the two most effective amino acids, namely, arginine and cysteine, revealed that they acted in different ways. Arginine prevented biofilm formation by reducing FLO11 gene expression; its addition did not affect cell viability and was even found to enhance cell metabolism (vitality marker) as determined by phenotype microarray (PM) analysis. On the contrary, the addition of cysteine reduced both cell viability and vitality as well as FLO11 expression. Thus, the use of cysteine and arginine as agents against biofilm formation can be diversified depending on the most desired action towards yeast growth.},
}
@article {pmid31300301,
year = {2019},
author = {Uribe-García, A and Paniagua-Contreras, GL and Monroy-Pérez, E and Bustos-Martínez, J and Hamdan-Partida, A and Garzón, J and Alanís, J and Quezada, R and Vaca-Paniagua, F and Vaca, S},
title = {Frequency and expression of genes involved in adhesion and biofilm formation in Staphylococcus aureus strains isolated from periodontal lesions.},
journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jmii.2019.05.010},
pmid = {31300301},
issn = {1995-9133},
abstract = {BACKGROUND/PURPOSE: The aim of this study was to characterize the Staphylococcus aureus strains isolated from periodontal lesions of patients, to determine the expression of genes involved in cell adhesion upon their infection of human epithelial cells using an in vitro model, its biofilm formation, and its resistance to antibiotics.<br><br>METHODS: S. aureus was analysed by PCR, Kirby-Bauer, and pulsed-field gel electrophoresis (PFGE), measuring gene expression by real-time PCR after infection of human cells in vitro.<br><br>RESULTS: S. aureus was identified in 18.6% (50/268) of the samples. All strains (n = 50) possessed the virulence genes spa (Staphylococcal protein A), coa (coagulase), and icaAB (intercellular adhesin); 96% (n = 48) possessed clfB (clumping factor B), and 88% (n = 44) possessed ebps (elastin-binding protein) and sdrD (serine aspartate repeat protein D). All strains were resistant to methicillin, ampicillin, dicloxacillin, cefotaxime, and penicillin, and were multidrug resistant to 6-12 antibiotics. PFGE analysis showed 37 different pulsed-field types and most strains (60.4%) had a unique pulsed-field type. Twenty-four distinct combinations of virulence genes and antibiotic-resistant phenotypes were identified.<br><br>CONCLUSION: Although S. aureus has been considered a transient member of the oral microbiota, our results indicate a high-level expression of virulence genes and multidrug resistance in the strains isolated from periodontal lesions. These strains might complicate the successful treatment of the disease.},
}
@article {pmid31300167,
year = {2019},
author = {Zhang, K and Lyu, L and Yao, S and Kang, T and Ma, Y and Pan, Y and Chang, M and Wang, Y and Furukawa, K and Zhu, T},
title = {Effects of vibration on anammox-enriched biofilm in a high-loaded upflow reactor.},
journal = {The Science of the total environment},
volume = {685},
number = {},
pages = {1284-1293},
doi = {10.1016/j.scitotenv.2019.06.082},
pmid = {31300167},
issn = {1879-1026},
mesh = {Ammonium Compounds/metabolism ; *Biofilms ; *Bioreactors ; Vibration ; Waste Disposal, Fluid/*methods ; },
abstract = {An upflow biofilm reactor was operated for 211 days to investigate the effects of vibration on anammox treatment performance. With vibration, the highest nitrogen removal rates (20 kg-N·m-3·d-1) were obtained on day 180. Since the vibration could directly applied on the biofilm, it could release the dinitrogen gas accumulated in the biofilm timely and reduce the internal mass transfer resistance sharply. The specific anammox activity increased by more than 3 times with a higher vibration intensity. Meanwhile, the unique random motion caused by mechanical vibration promotes the production of extracellular proteins. Moreover, the VSS reached 20.97 g·L-1 which was 1.6 times higher than the control reactor. Such enrichment method resulted in a hard and thick anammox biofilm with a special granular morphology, and the nitrite tolerance concentration could reach 500 mg-N·L-1. Operated with an adequate vibration intensity could maintain the biofilm thickness and conducive to improve the stability of the reactor. In addition, this technique also allowed the microorganisms inside the biofilm and those on the surface to reach the same culture conditions. Base on the batch experiments, intermittent vibration caused a decrease in energy consumption from about 7.757 (kW·h)·(kg-N)-1 in group 0-Lv7(60-60) to 0.912 (kW·h)·(kg-N)-1 in group 0-Lv7(5-60). Compared to the internal recycle without vibration, the energy consumption fell by a slice over 65%. Furthermore, the high-throughput sequencing results showed that the relative abundance of Candidatus Kuenenia in reactor 1 increased from 13.2% to 43.9%.},
}
@article {pmid31299899,
year = {2019},
author = {Azmi, K and Qrei, W and Abdeen, Z},
title = {Screening of genes encoding adhesion factors and biofilm production in methicillin resistant strains of Staphylococcus aureus isolated from Palestinian patients.},
journal = {BMC genomics},
volume = {20},
number = {1},
pages = {578},
doi = {10.1186/s12864-019-5929-1},
pmid = {31299899},
issn = {1471-2164},
support = {(M33-014).//Merck/ ; },
abstract = {BACKGROUND: Intercellular adhesion and biofilm production by Staphylococcus aureus makes these bacteria resistant to antimicrobial therapy. Here, Methicillin-resistant Staphylococcus aureus (MRSA) strains were characterized and the prevalence of genes encoding adhesion factors and biofilm formation was determined.<br><br>RESULTS: All 248 MRSA isolates identified by cefoxitin disc diffusion were positive for the mecA gene. SCCmec-IV was the most frequently detected genotype (92.7%) and SCCmec-IVa was also very prevalent (84.3%). The quantitative microtiter plate assay showed that all the isolates were able to produce biofilm with levels ranging from high (21%) to moderate (46.4%) to low (32.7%). All the strains possessed the icaD/icaA genes and produced biofilm (P < 0.05). None of the isolates possessed the bap gene. Furthermore, 94.8% of the isolates were positive for eno, 80.2% for clfA and for clfB, 78.2% for fnbA, 76.2% for ebps, 62.2% for fib, 39.9% for cna and 29.0% for fnbB. Also, nearly 69.8% of the isolates were positive for the gene sarA. All four agr groups were present: agr group 1 was predominant with 39.5%; agr group 3. agr group 2 and 3 strains carried more toxin-producing genes, and frequently produced more toxin. Sixty-six (26.6%) of the strains were multidrug resistant. All were vancomycin sensitive. Agr group I is more resistant to ciprofloxacin and gentamicin while agr group III is more resistant to erythromycin. Maximum sensitivity was to gentamicin and SXT, and they could be considered drugs of choice for controlling MRSA mediated infections in this region.<br><br>CONCLUSIONS: Biofilm development in MRSA might be an ica dependent and one needs to investigate the involvement of other global regulators, agr and sarA, and their contribution to the biofilm phenotype, as the high rate of biofilm production among the studied strains of S. aureus.},
}
@article {pmid31297368,
year = {2019},
author = {Nichols, D and Pimentel, MB and Borges, FTP and Hyoju, SK and Teymour, F and Hong, SH and Zaborina, OY and Alverdy, JC and Papavasiliou, G},
title = {Sustained Release of Phosphates From Hydrogel Nanoparticles Suppresses Bacterial Collagenase and Biofilm Formation in vitro.},
journal = {Frontiers in bioengineering and biotechnology},
volume = {7},
number = {},
pages = {153},
doi = {10.3389/fbioe.2019.00153},
pmid = {31297368},
issn = {2296-4185},
support = {R01 GM062344/GM/NIGMS NIH HHS/United States ; R21 AI124037/AI/NIAID NIH HHS/United States ; },
abstract = {Intestinal disease or surgical intervention results in local changes in tissue and host-derived factors triggering bacterial virulence. A key phenotype involved in impaired tissue healing is increased bacterial collagenase expression which degrades intestinal collagen. Antibiotic administration is ineffective in addressing this issue as it inadvertently eliminates normal flora while allowing pathogenic bacteria to &quot;bloom&quot; and acquire antibiotic resistance. Compounds that could attenuate collagenase production while allowing commensal bacteria to proliferate normally would offer major advantages without the risk of the emergence of resistance. We have previously shown that intestinal phosphate depletion in the surgically stressed host is a major cue that triggers P. aeruginosa virulence which is suppressed under phosphate abundant conditions. Recent findings indicate that orally administered polyphosphate, hexametaphosphate, (PPi) suppresses collagenase, and biofilm production of P. aeruginosa and S. marcescens in animal models of intestinal injury but does not attenuate E. faecalis induced collagenolytic activity (Hyoju et al., 2017). Systemic administration of phosphates, however, is susceptible to rapid clearance. Given the diversity of collagenase producing bacteria and the variation of phosphate metabolism among microbial species, a combination therapy involving different phosphate compounds may be required to attenuate pathogenic phenotypes. To address these barriers, we present a drug delivery approach for sustained release of phosphates from poly(ethylene) glycol (PEG) hydrogel nanoparticles. The efficacy of monophosphate (Pi)- and PPi-loaded NPs (NP-Pi and NP-PPi, respectively) and a combination treatment (NP-Pi + NP-PPi) in mitigating collagenase and biofilm production of gram-positive and gram-negative pathogens expressing high collagenolytic activity was investigated. NP-PPi was found to significantly decrease collagenase and biofilm production of S. marcescens and P. aeruginosa. Treatment with either NP-Pi or NP-Pi + NP-PPi resulted in more prominent decreases in E. faecalis collagenase compared to NP-PPi alone. The combination treatment was also found to significantly reduce P. aeruginosa collagenase production. Finally, significant attenuation in biofilm dispersal was observed with NP-PPi or NP-Pi + NP-PPi treatment across all test pathogens. These findings suggest that sustained release of different forms of phosphate confers protection against gram-positive and gram-negative pathogens, thereby providing a promising treatment to attenuate expression of tissue-disruptive bacterial phenotypes without eradicating protective flora over the course of intestinal healing.},
}
@article {pmid31297098,
year = {2019},
author = {Friedlander, A and Nir, S and Reches, M and Shemesh, M},
title = {Preventing Biofilm Formation by Dairy-Associated Bacteria Using Peptide-Coated Surfaces.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1405},
doi = {10.3389/fmicb.2019.01405},
pmid = {31297098},
issn = {1664-302X},
abstract = {Biofilm-forming bacteria, which colonize the surfaces of equipment in the dairy industry, may adversely affect the safety and quality of the milk and its products. Despite numerous efforts to combat biofilm formation, there is still no effective technological means to thoroughly solve the biofilm problem in the dairy industry. Here, we introduced peptide-based coating in order to modify the physical properties of the stainless steel surface by affecting its availability for bacterial adhesion. We found that the coated surface displays a notable decrease in the ability of bacterial cells to attach and to subsequently form biofilm by Gram-positive Bacillus licheniformis and Gram-negative Pseudomonas aeruginosa. Furthermore, the coated surface retained its anti-biofilm ability following its exposure to raw milk. Importantly, the modified surface did not affect the milk coagulation process or its nutritious properties and quality. Overall, this anti-biofilm approach may serve as an attractive solution for the dairy industry in its struggle against bacterial contamination.},
}
@article {pmid31297021,
year = {2019},
author = {Al-Yousef, HM and Sheikh, IA},
title = {β-Sitosterol derived compound from onion husks non-polar fraction reduces quorum sensing controlled virulence and biofilm production.},
journal = {Saudi pharmaceutical journal : SPJ : the official publication of the Saudi Pharmaceutical Society},
volume = {27},
number = {5},
pages = {664-672},
doi = {10.1016/j.jsps.2019.04.001},
pmid = {31297021},
issn = {1319-0164},
abstract = {Quorum sensing is an important regulatory factor of P. aeruginosa virulence induction such as BF, motility, formations of proteases, pyocyanin, and some toxins. The aim of the current study is to detect the effect of the pet.ether extract from onion husk and compound drive from it on quorum sensing and virulence formations of P. aeruginosa. Quorum sensing inhibiting effect of the pet.ether extract of onion husk and a compound drive from it, was evaluated by C. violaceum reporter using dilution method as well as an antioxidant by using DPPH. The efficacious of: Quorum sensing inhibiting on pet.ether fraction and compound derived from it, were investigated for their activities toward biofilm and pyocyanin synthesis as well as motility from P. aeruginosa. The pet.ether fraction and compound derived from it of onion husk exhibited potent antimicrobial, antioxidant and Quorum sensing inhibiting effects. The pet.ether fraction and compound derived from it possesses significant reduction on pyocyanin and biofilm induction of P. aeruginosa. Moreover, they significantly inhibited swimming motilities of P. aeruginosa. For the first time, our study showed the medical importance of Allium cepa L. as antimicrobial, antioxidant as well as Quorum sensing inhibiting and virulence suppressors of P. aeruginosa. Thus, these might emphasized on Allium cepa L as a natural source for attenuating toxins of the Pseudomonas.},
}
@article {pmid31295074,
year = {2019},
author = {Carter, MJ and Myntti, MF},
title = {Cost-utility of a biofilm-disrupting gel versus standard of care in chronic wounds: a Markov microsimulation model based on a randomised controlled trial.},
journal = {Journal of wound care},
volume = {28},
number = {Sup7},
pages = {S24-S38},
doi = {10.12968/jowc.2019.28.Sup7.S24},
pmid = {31295074},
issn = {0969-0700},
abstract = {OBJECTIVE: Analyse the cost-effectiveness and treatment outcomes of debridement (standard of care) plus BlastX, a biofilm-disrupting wound gel (group 1) or a triple-antibiotic, maximum-strength ointment (group 2), comparing a subset of patients who had not healed at four weeks using the ointment crossed-over to the biofilm-disrupting gel (group 3).<br><br>METHODS: A series of Markov microsimulation models were built using health states of an unhealed non-infected ulcer, healed ulcer, and infected non-healed ulcer and absorbing states of dead or amputation. All patients started with unhealed non-infected ulcers at cycle 0. Complications and healing rates were based on a randomised controlled trial (RCT). Costs were incurred by patients for procedures at outpatient wound care clinics and hospitals (if complications occurred) and were in the form of Medicare allowable charges. Quality-adjusted life years (QALYs) were computed using literature utility values. Incremental cost-effectiveness ratios (ICERs) were calculated for group 1 versus group 2, and group 3 versus group 2. One-way, multi-way and probabilistic sensitivity analysis (PSA) was conducted.<br><br>RESULTS: After one year, the base case ICER was $8794 per QALY for group 1 versus group 2, and $21,566 per QALY for group 3 versus group 2. Product cost and amputation rates had the most influence in one-way sensitivity analysis. PSA showed that the majority of costs were higher for group 1 but effectiveness values were always higher than for group 2. Average product use of 3.1ml per application represented 9.4% of the total group 1 cost (average $24.52 per application/$822.50 per group 1 patient). The biofilm-disrupting gel group performed substantially better than the current cost-effectiveness benchmarks, $8794 versus $50,000, respectively. Furthermore, when biofilm-disrupting gel treatment was delayed, as in group 3, the ICER outcomes were less substantial but it did remain cost-effective, suggesting the added benefits of immediate use of biofilm-disrupting gel. Also, when product cost assumptions used in the study were halved (Wolcott study usage), the model indicates important reductions in ICER to $966/QALY when comparing group 1 with group 2. It should be noted that product cost can hypothetically be affected not only by direct product purchase costs, but also by application intervals and technique. This suggests additional opportunities exist to optimise these parameters, maximising wound healing efficacy while providing significant cost savings to the payer.<br><br>CONCLUSION: The addition of the biofilm-disrupting gel treatment to standard of care is likely to be cost-effective in the treatment of chronic wounds but when delayed by as little as 9-12 weeks the ICER is still far less than current cost-effectiveness benchmarks. The implication for payers and decision-makers is that biofilm-disrupting gel should be used as a first-line therapy at the first clinic visit rather than waiting as it substantially decreases cost-utility.},
}
@article {pmid31294965,
year = {2019},
author = {Alizadeh, S and Abdul Rahim, A and Guo, B and Hawari, J and Ghoshal, S and Comeau, Y},
title = {Impacts of Continuous Inflow of Low Concentrations of Silver Nanoparticles on Biological Performance and Microbial Communities of Aerobic Heterotrophic Wastewater Biofilm.},
journal = {Environmental science &amp; technology},
volume = {53},
number = {15},
pages = {9148-9159},
doi = {10.1021/acs.est.9b01214},
pmid = {31294965},
issn = {1520-5851},
abstract = {Attached-growth wastewater processes are currently used in water resource recovery facilities (WRRFs) for required upgrades due to an increase in influent loading or to reach more stringent discharge criteria. Yet, the distribution and long-term inhibitory effects of silver nanoparticles (AgNPs) in attached-growth biological wastewater processes and their impact on involved microbial communities are poorly understood at relevant, low concentrations. Retention, distribution, and long-term inhibitory effect of polyvinylpyrrolidone (PVP)-coated AgNPs were evaluated in bench-scale moving bed biofilm reactors (MBBRs), achieving soluble organic matter removal, over a 64 day exposure to nominal concentrations of 10 and 100 μg/L. Distributions of continuously added AgNPs were characterized in the influent, bioreactor, and effluent of MBBRs using single particle inductively coupled plasma mass spectroscopy (spICP-MS). Aerobic heterotrophic biofilms in MBBRs demonstrated limited retention capacity for AgNPs over long-term exposure, with release of AgNPs, and Ag-rich biofilm sloughed from the carriers. Continuous exposure to both influent AgNP concentrations significantly decreased soluble chemical oxygen demand (SCOD) removal efficiency (11% to 31%) and reduced biofilm viability (8% to 30%). Specific activities of both intracellular dehydrogenase (DHA) and extracellular α-glucosidase (α-Glu) and protease (PRO) enzymes were significantly inhibited (8% to 39%) with an observed NP dose-dependent intracellular reactive oxygen species (ROS) production and shift in biofilm microbial community composition by day 64. Our results indicated that long-term exposure to AgNPs in biofilm processes at environmentally relevant concentrations can impact the treatment process stability and the quality of the discharged effluent.},
}
@article {pmid31294223,
year = {2018},
author = {Xaxiri, NA and Nikouli, E and Berillis, P and Kormas, KA},
title = {Bacterial biofilm development during experimental degradation of Melicertus kerathurus exoskeleton in seawater.},
journal = {AIMS microbiology},
volume = {4},
number = {3},
pages = {397-412},
doi = {10.3934/microbiol.2018.3.397},
pmid = {31294223},
issn = {2471-1888},
abstract = {Chitinolytic bacteria are widespread in marine and terrestrial environment, and this is rather a reflection of their principle growth substrate's ubiquity, chitin, in our planet. In this paper, we investigated the development of naturally occurring bacterial biofilms on the exoskeleton of the shrimp Melicertus kerathurus during its degradation in sea water. During a 12-day experiment with exoskeleton fragments in batch cultures containing only sea water as the growth medium at 18 °C in darkness, we analysed the formation and succession of biofilms by scanning electron microscopy and 16S rRNA gene diversity by next generation sequencing. Bacteria belonging to the γ- and α-Proteobacteria and Bacteroidetes showed marked (less or more than 10%) changes in their relative abundance from the beginning of the experiment. These bacterial taxa related to known chitinolytic bacteria were the Pseudolateromonas porphyrae, Halomonasaquamarina, Reinekea aestuarii, Colwellia asteriadis and Vibrio crassostreae. These bacteria could be considered as appropriate candidates for the degradation of chitinous crustacean waste from the seafood industry as they dominated in the biofilms developed on the shrimp's exoskeleton in natural sea water with no added substrates and the degradation of the shrimp exoskeleton was also evidenced.},
}
@article {pmid31294028,
year = {2019},
author = {Coelho, C and Gougeon, RD and Perepelkine, L and Alexandre, H and Guzzo, J and Weidmann, S},
title = {Chemical Transfers Occurring Through Oenococcus oeni Biofilm in Different Enological Conditions.},
journal = {Frontiers in nutrition},
volume = {6},
number = {},
pages = {95},
doi = {10.3389/fnut.2019.00095},
pmid = {31294028},
issn = {2296-861X},
abstract = {Chardonnay wine malolactic fermentations were carried out to evaluate the chemical transfers occurring at the wood/wine interface in the presence of two different bacterial lifestyles. To do this, Oenococcus oeni was inoculated into must and wine in its planktonic and biofilm lifestyles, whether adhering or not to oak chips, leading to three distinct enological conditions: (i) post-alcoholic fermentation inoculation in wine in the absence of oak chips, (ii) post-alcoholic fermentation inoculation in wine in the presence of oak chips, and (iii) co-inoculation of both Saccharomyces cerevisiae and O. oeni directly in Chardonnay musts in the presence of oak chips. Classical microbiological and physico-chemical parameters analyzed during the fermentation processes confirmed that alcoholic fermentation was completed identically regardless of the enological conditions, and that once O. oeni had acquired a biofilm lifestyle in the presence or absence of oak, malolactic fermentation occurred faster and with better reproducibility compared to planktonic lifestyles. Analyses of volatile components (higher alcohols and wood aromas) and non-volatile components (Chardonnay grape polyphenols) carried out in the resulting wines revealed chemical differences, particularly when bacterial biofilms were present at the wood interface. This study revealed the non-specific trapping activity of biofilm networks in the presence of wood and grape compounds regardless of the enological conditions. Changes of concentrations in higher alcohols reflected the fermentation bioactivity of bacterial biofilms on wood surfaces. These chemical transfers were statistically validated by an untargeted approach using Excitation Emission Matrices of Fluorescence combined with multivariate analysis to discriminate innovative enological practices during winemaking and to provide winemakers with an optical tool for validating the biological and chemical differentiations occurring in wine that result from their decisions.},
}
@article {pmid31293539,
year = {2019},
author = {Schiffer, C and Hilgarth, M and Ehrmann, M and Vogel, RF},
title = {Bap and Cell Surface Hydrophobicity Are Important Factors in Staphylococcus xylosus Biofilm Formation.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1387},
doi = {10.3389/fmicb.2019.01387},
pmid = {31293539},
issn = {1664-302X},
abstract = {Staphylococcus (S.) xylosus is a coagulase-negative Staphylococcus species naturally present in food of animal origin with a previously described potential for biofilm formation. In this study we characterized biofilm formation of five selected strains isolated from raw fermented dry sausages, upon different growth conditions. Four strains exhibited a biofilm positive phenotype with strain-dependent intensities. Biofilm formation of S. xylosus was influenced by the addition of glucose, sodium chloride and lactate to the growth medium, respectively. It was further dependent on strain-specific cell surface properties. Three strains exhibited hydrophobic and two hydrophilic cell surface properties. The biofilm positive hydrophilic strain TMW 2.1523 adhered significantly better to hydrophilic than to hydrophobic supports, whereas the differences in adherence to hydrophobic versus hydrophilic supports were not as distinct for the hydrophobic strains TMW 2.1023, TMW 2.1323, and TMW 2.1521. Comparative genomics enabled prediction of functional biofilm-related genes and link these to phenotypic variations. While a wide range of biofilm associated factors/genes previously described for S. aureus and S. epidermidis were absent in the genomes of the five strains analyzed, they all possess the gene encoding biofilm associated protein Bap. The only biofilm negative strain TMW 2.1602 showed a mutation in the bap sequence. This study demonstrates that Bap and surface hydrophobicity are important factors in S. xylosus biofilm formation with potential impact on the assertiveness of a starter strain against autochthonous staphylococci by competitive exclusion during raw sausage fermentation.},
}
@article {pmid31293528,
year = {2019},
author = {Ranjith, K and Ramchiary, J and Prakash, JSS and Arunasri, K and Sharma, S and Shivaji, S},
title = {Gene Targets in Ocular Pathogenic Escherichia coli for Mitigation of Biofilm Formation to Overcome Antibiotic Resistance.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1308},
doi = {10.3389/fmicb.2019.01308},
pmid = {31293528},
issn = {1664-302X},
abstract = {The present work is an attempt to establish the functionality of genes involved in biofilm formation and antibiotic resistance in an ocular strain of Escherichia coli (L-1216/2010) which was isolated and characterized from the Vitreous fluid of a patient with Endophthalmitis. For this purpose, seven separate gene-specific knockout mutants were generated by homologous recombination in ocular E. coli. The genes that were mutated included three transmembrane genes ytfR (ABC transporter ATP-binding protein), mdtO (multidrug efflux system) and tolA (inner membrane protein), ryfA coding for non-coding RNA and three metabolic genes mhpA (3-3-hydroxyphenylpropionate 1,2-dioxygenase), mhpB (2,3-di hydroxyphenylpropionate 1,2-dioxygenase), and bdcR (regulatory gene of bdcA). Mutants were validated by sequencing and Reverse transcription-PCR and monitored for biofilm formation by XTT method and confocal microscopy. The antibiotic susceptibility of the mutants was also ascertained. The results indicated that biofilm formation was inhibited in five mutants (ΔbdcR, ΔmhpA, ΔmhpB, ΔryfA, and ΔtolA) and the thickness of biofilm reduced from 17.2 μm in the wildtype to 1.5 to 4.8 μm in the mutants. Mutants ΔytfR and ΔmdtO retained the potential to form biofilm. Complementation of the mutants with the wild type gene restored biofilm formation potential in all mutants except in ΔmhpB. The 5 mutants which lost their ability to form biofilm (ΔbdcR, ΔmhpA, ΔmhpB, ΔtolA, and ΔryfA) did not exhibit any change in their susceptibility to Ceftazidime, Cefuroxime, Ciprofloxacin, Gentamicin, Cefotaxime, Sulfamethoxazole, Imipenem, Erythromycin, and Streptomycin in the planktonic phase compared to wild type ocular E. coli. But ΔmdtO was the only mutant with altered MIC to Sulfamethoxazole, Imipenem, Erythromycin, and Streptomycin both in the planktonic and biofilm phase. This is the first report demonstrating the involvement of the metabolic genes mhpA and mhpB and bdcR (regulatory gene of bdcA) in biofilm formation in ocular E. coli. In addition we provide evidence that tolA and ryfA are required for biofilm formation while ytfR and mdtO are not required. Mitigation of biofilm formation to overcome antibiotic resistance could be achieved by targeting the genes bdcR, mhpA, mhpB, ryfA, and tolA.},
}
@article {pmid31293526,
year = {2019},
author = {Gannesen, AV and Zdorovenko, EL and Botchkova, EA and Hardouin, J and Massier, S and Kopitsyn, DS and Gorbachevskii, MV and Kadykova, AA and Shashkov, AS and Zhurina, MV and Netrusov, AI and Knirel, YA and Plakunov, VK and Feuilloley, MGJ},
title = {Composition of the Biofilm Matrix of Cutibacterium acnes Acneic Strain RT5.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1284},
doi = {10.3389/fmicb.2019.01284},
pmid = {31293526},
issn = {1664-302X},
abstract = {In skin, Cutibacterium acnes (former Propionibacterium acnes) can behave as an opportunistic pathogen, depending on the strain and environmental conditions. Acneic strains of C. acnes form biofilms inside skin-gland hollows, inducing inflammation and skin disorders. The essential exogenous products of C. acnes accumulate in the extracellular matrix of the biofilm, conferring essential bacterial functions to this structure. However, little is known about the actual composition of the biofilm matrix of C. acnes. Here, we developed a new technique for the extraction of the biofilm matrix of Gram-positive bacteria without the use of chemical or enzymatic digestion, known to be a source of artifacts. Our method is based on the physical separation of the cells and matrix of sonicated biofilms by ultracentrifugation through a CsCl gradient. Biofilms were grown on the surface of cellulose acetate filters, and the biomass was