@article {pmid31120391,
year = {2019},
author = {Zhou, X and Li, M and Xu, L and Shi, C and Shi, X},
title = {Characterization of Antibiotic Resistance Genes, Plasmids, Biofilm Formation, and In Vitro Invasion Capacity of Salmonella Enteritidis Isolates from Children with Gastroenteritis.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2018.0421},
pmid = {31120391},
issn = {1931-8448},
abstract = {Objectives: The primary aim of this study was to investigate the presence of antibiotic resistance genes (ARGs) and plasmid replicon types for 75 multidrug-resistant (MDR) Salmonella Enteritidis isolates from children with gastroenteritis. We also evaluated the association among biofilm formation, in vitro invasion capacity, and antibiotic resistance phenotypes. Materials and Methods: Twenty-two ARGs and 18 different plasmid incompatibility types were investigated using polymerase chain reaction (PCR) and DNA sequencing. In vitro invasion capacity of S. Enteritidis isolates possessing different antibiotic resistance patterns was assessed using the Caco2 human intestinal epithelial cell line and biofilm formation was performed in a 96-well polystyrene well format using crystal violet detection. Results: The presence of plasmid-mediated quinolone resistance genes and β-lactamase genes was established using PCR amplification. All the tested S. Enteritidis isolates that were fluoroquinolone resistant possessed gyrA mutations and 50% also possessed mutations in parC. MDR S. Enteritidis isolates containing three (29/75) or four (21/75) plasmid replicon types were predominant and 71/75 carried both FIIs and FIC replicon-type plasmids. MDR isolates were strong or moderate biofilm producers and a significant positive association (p < 0.05) between antibiotic resistance and biomass of biofilms was observed in the strains assayed. A ceftiofur-resistant strain was significantly more invasive (p < 0.01) than the other isolates. Conclusions: We observed a high incidence of ARGs and diversity of plasmids in S. Enteritidis isolates from children. Biofilm formation and invasion capacity highlight a significant hazard to public health.},
}
@article {pmid31120377,
year = {2019},
author = {Cowle, MW and Webster, G and Babatunde, AO and Bockelmann-Evans, BN and Weightman, AJ},
title = {Impact of Flow Hydrodynamics and Pipe Material Properties on Biofilm Development within Drinking Water Systems.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-37},
doi = {10.1080/09593330.2019.1619844},
pmid = {31120377},
issn = {1479-487X},
abstract = {The aim of this study was to investigate the combined impact of flow hydrodynamics and pipe material on biofilm development in drinking water distribution systems (DWDS). Biofilms were formed on four commonly used pipe materials within a series of purpose built flow cell reactors at two different flow regimes (high and low flow). Pipe materials assessed within this study were polyvinyl chloride (PVC), polypropylene (PP), structured wall high-density polyethylene (Str-HDPE) and solid wall high-density polyethylene (S-HDPE). Results indicate that varying amounts of microbial material with different morphologies were present depending on the pipe material and conditioning. The amount of microbial biomass on pipe material coupons was typically greater in the low flow assay; biofilms incubated in the high flow assay were seemingly more isolated than the low flow assay. Biofilm development was inhibited at high shear, indicating shear forces imposed by flow conditions were above the critical levels for biofilm attachment. Alphaproteobacteria was the predominant bacterial group within the biofilms incubated within the low flow assay and represented 48% of evaluated phylotypes; whilst within the high flow assay, Betaproteobacteria (45%) and Gammaproteobacteria (33%) were the dominant groups. The opportunistic pathogens, Sphingomonas and Pseudomonas were found to be particularly abundant in biofilms incubated within the low flow assay, and only rarely found within biofilms incubated at high flow (only Str-HDPE coupons). This suggests that these bacteria have limited ability to propagate within biofilms under high shear conditions without sufficient protection (roughness). These findings expand on knowledge relating to the impact of surface roughness and flow hydrodynamics on biofilm development within DWDS.},
}
@article {pmid31119950,
year = {2019},
author = {Irankhah, S and Abdi Ali, A and Mallavarapu, M and Soudi, MR and Subashchandrabose, S and Gharavi, S and Ayati, B},
title = {Ecological role of Acinetobacter calcoaceticus GSN3 in natural biofilm formation and its advantages in bioremediation.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-15},
doi = {10.1080/08927014.2019.1597061},
pmid = {31119950},
issn = {1029-2454},
abstract = {This study assessed the role of a new Acinetobacter calcoaceticus strain, GSN3, with biofilm-forming and phenol-degrading abilities. Three biofilm reactors were spiked with activated sludge (R1), green fluorescent plasmid (GFP) tagged GSN3 (R2), and their combination (R3). More than 99% phenol removal was achieved during four weeks in R3 while this efficiency was reached after two and four further operational weeks in R2 and R1, respectively. Confocal scanning electron microscopy revealed that GSN3-gfp strains appeared mostly in the deeper layers of the biofilm in R3. After four weeks, almost 7.07 × 107 more attached sludge cells were counted per carrier in R3 in comparison to R1. Additionally, the higher numbers of GSN3-gfp in R2 were unable to increase the efficiency as much as measured in R3. The presence of GSN3-gfp in R3 conveyed advantages, including enhancement of cell immobilization, population diversity, metabolic cooperation and ultimately treatment efficiency.},
}
@article {pmid31118922,
year = {2019},
author = {Zhang, M and Zhang, X and Tong, L and Ou, D and Wang, Y and Zhang, J and Wu, Q and Ye, Y},
title = {Random Mutagenesis Applied to Reveal Factors Involved in Oxidative Tolerance and Biofilm Formation in Foodborne Cronobacter malonaticus.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {877},
doi = {10.3389/fmicb.2019.00877},
pmid = {31118922},
issn = {1664-302X},
abstract = {Cronobacter species are linked with life-treating diseases in neonates and show strong tolerances to environmental stress. However, the information about factors involved in oxidative tolerance in Cronobacter remains elusive. Here, factors involved in oxidative tolerance in C. malonaticus were identified using a transposon mutagenesis. Eight mutants were successfully screened based on a comparison of the growth of strains from mutant library (n = 215) and wild type (WT) strain under 1.0 mM H2O2. Mutating sites including thioredoxin 2, glutaredoxin 3, pantothenate kinase, serine/threonine protein kinase, pyruvate kinase, phospholipase A, ferrous iron transport protein A, and alanine racemase 2 were successfully identified by arbitrary PCR and sequencing alignment. Furthermore, the comparison about quantity and structure of biofilms formation among eight mutants and WT was determined using crystal violet staining (CVS), scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Results showed that the biofilms of eight mutants significantly decreased within 48 h compared to that of WT, suggesting that mutating genes play important roles in biofilm formation under oxidative stress. The findings provide valuable information for deeply understanding molecular mechanism about oxidative tolerance of C. malonaticus.},
}
@article {pmid31118702,
year = {2019},
author = {Shrestha, LB and Baral, R and Khanal, B},
title = {Comparative study of antimicrobial resistance and biofilm formation among Gram-positive uropathogens isolated from community-acquired urinary tract infections and catheter-associated urinary tract infections.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {957-963},
doi = {10.2147/IDR.S200988},
pmid = {31118702},
issn = {1178-6973},
abstract = {Background: Gram-positive cocci have emerged to be an important cause of urinary tract infection (UTI) both in community-acquired UTI (Com-UTI) and catheter-associated urinary tract infection (CA-UTI). The objective of this study was to investigate the frequency of Gram-positive cocci urinary tract infections, their susceptibility patterns to commonly used antimicrobial agents and the biofilm forming property with respect to catheter-associated UTI and community-acquired UTI. Methods: A total of 1,360 urine samples from indwelling catheter and 10,423 from mid-stream urine were obtained during a 6-month period and processed following standard microbiological guidelines. Biofilm formation was detected using congo red agar (CRA), tube method (TM) and tissue culture plate (TCP) method. Chi-square test and independent sample t-test were employed to calculate the significance. Statistical significance was set at P-value ≤0.05. Results: The infection rate was significantly higher in CA-UTI as compared to Com-UTI (25% vs 18%, p=0.0001). Among 2,216 organisms isolated, 471 were Gram-positive cocci; 401 were obtained from Com-UTI while 70 were from CA-UTI. Enterococcus faecalis was the most common organism isolated from Com-UTI, while Staphylococcus aureus was commonest among CA-UTI. Multi-drug resistance, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci were also significantly higher in CA-UTI as compared to Com-UTI. Biofilm-forming property was significantly higher in CA-UTI than Com-UTI. The sensitivity of congo red agar method and tube method was 79% and 81.9% respectively and specificity was 98.5% each. Antimicrobial resistance was significantly higher in biofilm-formers as compared to non-formers. Conclusion: Gram-positive bacteria are a significant cause of both CA-UTI and Com-UTI with Enterococcus faecalis and Staphylococcus aureus as common pathogen. Biofilm formation and multi-drug resistance is significantly higher in CA-UTI than Com-UTI. Routine surveillance of antimicrobial resistance and biofilm formation is necessary in all cases of UTI to ensure the proper management of patients.},
}
@article {pmid31118466,
year = {2019},
author = {Dettweiler, M and Lyles, JT and Nelson, K and Dale, B and Reddinger, RM and Zurawski, DV and Quave, CL},
title = {American Civil War plant medicines inhibit growth, biofilm formation, and quorum sensing by multidrug-resistant bacteria.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {7692},
doi = {10.1038/s41598-019-44242-y},
pmid = {31118466},
issn = {2045-2322},
support = {52006923//Howard Hughes Medical Institute (HHMI)/ ; R21 AI136563//U.S. Department of Health &amp; Human Services | NIH | Office of Extramural Research, National Institutes of Health (OER)/ ; },
abstract = {A shortage of conventional medicine during the American Civil War (1861-1865) spurred Confederate physicians to use preparations of native plants as medicines. In 1863, botanist Francis Porcher compiled a book of medicinal plants native to the southern United States, including plants used in Native American traditional medicine. In this study, we consulted Porcher's book and collected samples from three species that were indicated for the formulation of antiseptics: Liriodendron tulipifera, Aralia spinosa, and Quercus alba. Extracts of these species were tested for the ability to inhibit growth in three species of multidrug-resistant pathogenic bacteria associated with wound infections: Staphylococcus aureus, Klebsiella pneumoniae, and Acinetobacter baumannii. Extracts were also tested for biofilm and quorum sensing inhibition against S. aureus. Q. alba extracts inhibited growth in all three species of bacteria (IC50 64, 32, and 32 µg/mL, respectively), and inhibited biofilm formation (IC50 1 µg/mL) in S. aureus. L. tulipifera extracts inhibited biofilm formation (IC50 32 µg/mL) in S. aureus. A. spinosa extracts inhibited biofilm formation (IC50 2 µg/mL) and quorum sensing (IC50 8 µg/mL) in S. aureus. These results support that this selection of plants exhibited some antiseptic properties in the prevention and management of wound infections during the conflict.},
}
@article {pmid31117281,
year = {2019},
author = {Rajkowska, K and Nowicka-Krawczyk, P and Kunicka-Styczyńska, A},
title = {Effect of Clove and Thyme Essential Oils on Candida Biofilm Formation and the Oil Distribution in Yeast Cells.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {10},
pages = {},
doi = {10.3390/molecules24101954},
pmid = {31117281},
issn = {1420-3049},
abstract = {Candida biofilm structure is particularly difficult to eradicate, since biofilm is much more resistant to antifungal agents than planktonic cells. In this context, a more effective strategy seems to be the prevention of biofilm formation than its eradication. The aim of the study was to examine whether the process of initial colonization of materials (glass, polyethylene terephthalate, polypropylene) by food-borne Candida sp. can be impeded by clove and thyme essential oils, used at their minimal inhibitory concentrations. In the presence of clove oil, 68.4-84.2% of the yeast tested showed a statistically significant reduction in biofilm formation, depending on the material. After treatment with thyme oil, statistically significant decrease in biofilm cell numbers was observed for 63.2-73.7% of yeasts. Confocal laser scanning microscopy showed diverse compounds of clove and thyme oils that were disparately located in C. albicans cell, on a cell wall and a cell membrane, in cytoplasm, and in vacuoles, depicting the multidirectional action of essential oils. However, essential oils that were used in sub-inhibitory concentration were sequestrated in the yeast vacuoles, which indicate the activation of Candida defense mechanisms by cell detoxification. Clove and thyme essential oils due to their anti-biofilm activity can be efficiently used in the prevention of the tested abiotic surfaces colonization by Candida sp.},
}
@article {pmid31113117,
year = {1993},
author = {Sasahara, KC and Zottola, EA},
title = {Biofilm Formation by Listeria monocytogenes Utilizes a Primary Colonizing Microorganism in Flowing Systems.},
journal = {Journal of food protection},
volume = {56},
number = {12},
pages = {1022-1028},
doi = {10.4315/0362-028X-56.12.1022},
pmid = {31113117},
issn = {1944-9097},
abstract = {Listeria monocytogenes serotype 3a and Pseudomonas fragi ATCC 4973 were examined for attachment capability and biofilm development on glass coverslips under flowing systems. Tryptic soy broth supplemented with yeast extract was the growth medium. A continuous flow slide chamber was developed for in situ observations using phase-contrast microscopy. Glass coverslips were examined by epifluorescent and scanning electron microscopy for biofilm formation. The ultrastructure of attached test organisms was examined for the presence of exopolymers using transmission electron microscopy. In pure cultures, attachment of L. monocytogenes to glass coverslips was sparse, while P. fragi accumulated on glass coverslips as a confluent layer of cells. When L. monocytogenes was grown in mixed culture with P. fragi , an exopolymer-producing microorganism, attachment and microcolony formation by L. monocytogenes was enhanced. Results suggest that under flowing conditions the presence of an exopolymer-producing microorganism may be more important than hydrophobicity, surface charge, or flagellar movement in attachment of L. monocytogenes to inert surfaces.},
}
@article {pmid31113100,
year = {1993},
author = {Wirtanen, G and Mattila-Sandholm, T},
title = {Epifluorescence Image Analysis and Cultivation of Foodborne Biofilm Bacteria Grown on Stainless Steel Surfaces.},
journal = {Journal of food protection},
volume = {56},
number = {8},
pages = {678-683},
doi = {10.4315/0362-028X-56.8.678},
pmid = {31113100},
issn = {1944-9097},
abstract = {In this study, biofilm was grown on stainless steel surfaces (AISI 304) for 2, 5, and 10 d at 25°C in slime broth inoculated with the food spoilage microbes Bacillus subtilis , Listeria monocytogenes , Pediococcus pentosaceus , and Pseudomonas fragi . The biofilm developing on steel surfaces were investigated using conventional plating, quantitative glycocalyx determination, and epifluorescence microscopy with image analysis. The results showed that B. subtilis and P. fragi could easily be cultivated after 2 d growth. After a growth period of 10 d, the cells were difficult to cultivate from the surface, and the growth was detected better by microscopy. L. monocytogenes , on the other hand, could easily be detected by cultivation after 2, 5, and 10 d. The greatest amount of slime was produced by P. pentosaceus , as was also shown by epifluorescence microscopy.},
}
@article {pmid31113053,
year = {1993},
author = {Ronner, AB and Wong, ACL},
title = {Biofilm Development and Sanitizer Inactivation of Listeria monocytogenes and Salmonella typhimurium on Stainless Steel and Buna-n Rubber.},
journal = {Journal of food protection},
volume = {56},
number = {9},
pages = {750-758},
doi = {10.4315/0362-028X-56.9.750},
pmid = {31113053},
issn = {1944-9097},
abstract = {Biofilm formation by seven strains of Listeria monocytogenes and one strain of Salmonella typhimurium on stainless steel and Buna-n rubber was examined under two nutrient conditions. The type of surface, nutrient level, and organism influenced biofilm development and production of extracellular materials. Buna-n had a strong bacteriostatic effect on L. monocytogenes , and biofilm formation on Buna-n under low nutrient conditions was reduced for four of the seven strains tested. Buna-n was less bacteriostatic toward S. typhimurium . It inhibited the growth of several other pathogens to varying degrees. An ethylene propylene diamine monomer rubber was less inhibitory than Buna-n, and Viton rubber had no effect. The effectiveness of sanitizers on biofilm bacteria was examined. Biofilms were challenged with four types of detergent and nondetergent sanitizers. Resistance to sanitizers was strongly influenced by the type of surface. Bacterial biofilm populations on stainless steel were reduced 3-5 log by all the sanitizers, but those on Buna-n were resistant to these sanitizers and were reduced less than 1-2 log. In contrast, planktonic (suspended) bacteria were reduced 7-8 log by these sanitizers. Chlorine and anionic acid sanitizers generally removed extracellular materials from biofilms better than iodine and quaternary ammonium detergent sanitizers. Scanning electron microscopy demonstrated that biofilm cells and extracellular matrices could remain on sanitized biofilm cells and extracellular matrices could remain surfaces from which no viable cells were recovered.},
}
@article {pmid31113042,
year = {1993},
author = {Ren, TJ and Frank, JF},
title = {Susceptibility of Starved Planktonic and Biofilm Listeria monocytogenes to Quaternary Ammonium Sanitizer as Determined by Direct Viable and Agar Plate Counts.},
journal = {Journal of food protection},
volume = {56},
number = {7},
pages = {573-576},
doi = {10.4315/0362-028X-56.7.573},
pmid = {31113042},
issn = {1944-9097},
abstract = {Effective food plant cleaning procedures remove microbial nutrients from surfaces, which could result in contaminating bacteria being subject to a starvation microenvironment. This research investigated the effect of starvation on the susceptibility of Listeria monocytogenes to benzalkonium chloride (BAC). Cells were starved in phosphate buffer at 21°C for 4 d. Biofilm and planktonic listeriae reacted differently to starvation. When cells were grown in tryptic soy broth (TSB), starvation reduced the susceptibility of planktonic cells to BAC by 2.3- to 4.7-fold but had no effect on the susceptibility of biofilm cells. Planktonic cells grown in diluted TSB were 390 times more resistant than normal TSB-grown cells, but when these cells were starved, they lost their increased resistance. This phenomenon was not observed with biofilm cells. Increased resistance of listeriae grown in diluted TSB was associated with dilution of the salt/buffer components of the medium. Sanitizer-treated cells were enumerated by using tryptic soy agar-yeast extract pour plates and by a direct viable count method. Results indicate that some cells exposed to BAC were not detected by the plate count procedure but were still viable.},
}
@article {pmid31117001,
year = {2019},
author = {Huang, TC and Chen, CJ and Chen, CC and Ding, SJ},
title = {Enhancing osteoblast functions on biofilm-contaminated titanium alloy by concentration-dependent use of methylene blue-mediated antimicrobial photodynamic therapy.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.05.021},
pmid = {31117001},
issn = {1873-1597},
abstract = {The concentration of methylene blue (MB) photosensitizer could affect the eradication efficacy of antimicrobial photodynamic therapy (aPDT) in the treatment of contaminated implants, which is linked to the osseointegration of the implant. This was the first report of evaluating osteoblast functions on the contaminated SLA (sandblasting, large-grit and acid-etching) Ti alloy surfaces after the concentration-dependent use of MB-aPDT. Totally 1,164 SLA discs were randomly distributed for the analyses of antibacterial efficacy and osteoblast functions. Gram-negative (Aggregatibacter actinomycetemcomitans; A. actinomycetemcomitans) or Gram-positive (Streptococcus mutans; S. mutans) adhered on disc samples was subjected to aPDT with different MB concentrations (200, 250, 300, 350, and 400 μg/mL) using 660 nm diode laser with maximum output 80 mW for 1 min irradiation (4.8 J/cm2). Bactericidal effect was examined by viability, morphology, and lipopolysaccharide (LPS) assays. The disinfected disc surfaces by MB-aPDT to support osteoblast-like MG63 attachment, proliferation, differentiation, and mineralization were assessed for the predetermined culture time intervals. The statistical differences between the means were performed using a one-way analysis of variance (ANOVA) with a post hoc Scheffe test. The results of the morphology observation and bacterial survival examination consistently indicated a remarkably lower quantity of bacterial colonies on biofilm-contaminated surfaces after the aPDT treatment with higher MB concentration. Similarly, the higher MB concentration in aPDT resulted in the lower LPS amounts remaining on the A. actinomycetemcomitans-contaminated surfaces. Intriguingly, the expression of osteoblast cultured on disinfected surfaces using aPDT with higher MB concentration was comparable to the control without contamination. Within the limits of this in vitro model, this formulation of 400 μg/mL MB used in aPDT may be not only the lethal concentration against the 2 bacteria-contaminated implants, but it could also enhance the osteoblast functions on the contaminated implants. Nevertheless, the efficacy in the clinical practice for peri-implantitis therapy remains to be studied.},
}
@article {pmid31116790,
year = {2019},
author = {Feng, R and Zhao, G and Yang, Y and Xu, M and Huang, S and Sun, G and Guo, J and Li, J},
title = {Enhanced biological removal of intermittent VOCs and deciphering the roles of sodium alginate and polyvinyl alcohol in biofilm formation.},
journal = {PloS one},
volume = {14},
number = {5},
pages = {e0217401},
doi = {10.1371/journal.pone.0217401},
pmid = {31116790},
issn = {1932-6203},
abstract = {Developing a robust biofilm is a prerequisite for a biotrickling filter to obtain the good performance in removing volatile organic compounds (VOCs). But the biofilm formation can be seriously disturbed under intermittent loading condition due to carbon starvation stress in idle time. In this study, a biotrickling filter, with its packing materials being modified by 3% sodium alginate and 5% polyvinyl alcohol (v/v = 1:3), was employed to treat intermittent VOCs. Results showed that the removal efficiencies of toluene, ethylbenzene, p-xylene, m-xylene, and o-xylene was significantly enhanced in the BTF compared to the control one. Under relatively lower inlet loading, nearly complete removal of the five pollutants was achieved. A quantitative analysis showed that the concentration of total organic compound (TOC) in the leachate maintained at a high level, and had a strongly positive correlation with the divergence of microbial communities. The capacity of biofilm formation in the BTF was approximately four-fold higher than the control BTF, while the quantity of EPS secreted was more than ten-fold. EPS comprised largely of protein, and to less extent, polysaccharide. The biofilm formed on the modified packing materials maintained higher levels of microbial diversity and stability, even when modifiers were complete depleted or the VOCs inlet loading was increased. This study highlights the importance of packing materials for reducing the gap in performance between laboratory and industrial applications of BTFs.},
}
@article {pmid31116789,
year = {2019},
author = {Huang, MY and Woolford, CA and May, G and McManus, CJ and Mitchell, AP},
title = {Circuit diversification in a biofilm regulatory network.},
journal = {PLoS pathogens},
volume = {15},
number = {5},
pages = {e1007787},
doi = {10.1371/journal.ppat.1007787},
pmid = {31116789},
issn = {1553-7374},
abstract = {Genotype-phenotype relationships can vary extensively among members of a species. One cause of this variation is circuit diversification, the alteration of gene regulatory relationships among members of a species. Circuit diversification is thought to be a starting point for the circuit divergence or rewiring that occurs during speciation. How widespread is circuit diversification? Here we address this question with the fungal pathogen Candida albicans, which forms biofilms rich in distinctive hyphal cells as a prelude to infection. Our understanding of the biofilm/hyphal regulatory network comes primarily from studies of one clinical isolate, strain SC5314, and its marked derivatives. We used CRISPR-based methods to create mutations of four key biofilm transcription factor genes-BCR1, UME6, BRG1, and EFG1 -in SC5314 and four additional clinical isolates. Phenotypic analysis revealed that mutations in BCR1 or UME6 have variable impact across strains, while mutations in BRG1 or EFG1 had uniformly severe impact. Gene expression, sampled with Nanostring probes and examined comprehensively for EFG1 via RNA-Seq, indicates that regulatory relationships are highly variable among isolates. Our results suggest that genotype-phenotype relationships vary in this strain panel in part because of differences in control of BRG1 by BCR1, a hypothesis that is supported through engineered constitutive expression of BRG1. Overall, the data show that circuit diversification is the rule, not the exception, in this biofilm/hyphal regulatory network.},
}
@article {pmid31116437,
year = {2019},
author = {Abbondante, S and Pearlman, E},
title = {Breaching bacterial biofilm with neutrophil α-mannosidase.},
journal = {Journal of leukocyte biology},
volume = {},
number = {},
pages = {},
doi = {10.1002/JLB.4CE0419-139R},
pmid = {31116437},
issn = {1938-3673},
}
@article {pmid31116394,
year = {2019},
author = {Laulund, ASB and Trøstrup, H and Lerche, CJ and Thomsen, K and Christophersen, L and Calum, H and Høiby, N and Moser, C},
title = {Synergistic effect of immunomodulatory S100A8/A9 and ciprofloxacin against Pseudomonas aeruginosa biofilm in a murine chronic wound model.},
journal = {Pathogens and disease},
volume = {},
number = {},
pages = {},
doi = {10.1093/femspd/ftz027},
pmid = {31116394},
issn = {2049-632X},
abstract = {The majority of chronic wounds are associated with bacterial biofilms recalcitrant to antibiotics and host responses.Immunomodulatory S100A8/A9 is suppressed in P. aeruginosa biofilms infected wounds. We aimed at investigating a possible additive effect between S100A8/A9 and ciprofloxacin against biofilms.<br><br>MATERIALS/METHODS: Thirty-two mice were injected with alginate embedded P.aeruginosa following a third-degree burn. Mice were randomized into four groups receiving combination ciprofloxacin and S100A8/A9 or monotherapy ciprofloxacin, S100A8/A9 or placebo. Evaluated by host responses and quantitative bacteriology in wounds.In addition, in vitro checkerboard analysis was performed, with P. aeruginosa and ascending S100A8/A9 and ciprofloxacin concentrations.<br><br>RESULTS: S100A8/A9 augmented the effect of ciprofloxacin in vivo, by lowering bacterial quantity compared to the placebo arm and the two mono-intervention groups (P < 0.0001).S100A8 and 100A9 were increased in the double-treated group as compared to the mono-intervention groups (P = 0.032, P = 0.0023). TIMP-1 and KC/CXCL-1 were increased in the double-intervention group compared to the S100A8/A9 group (P = 0.050, P = 0.050).No in vitro synergism was detected.<br><br>CONCLUSION: The observed ciprofloxacin augmenting effect of S100A8/A9 in vivo was not confirmed by checkerboard analysis indicating dependence of host cells for the S100A8/A9 effect. S100A8/A9 and ciprofloxacin is a promising therapy for optimizing chronic wound treatment.},
}
@article {pmid31115692,
year = {2019},
author = {Daood, U and Burrow, MF and Yiu, CKY},
title = {Effect of a novel quaternary ammonium silane cavity disinfectant on cariogenic biofilm formation.},
journal = {Clinical oral investigations},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00784-019-02928-7},
pmid = {31115692},
issn = {1436-3771},
abstract = {OBJECTIVE: Evaluate effect of quaternary ammonium silane (QAS) cavity disinfectant on cariogenic biofilm.<br><br>MATERIALS AND METHODS: Single- (Streptococcus mutans or Lactobacillus acidophilus), dual- (Streptococcus mutans/Lactobacillus Acidophilus), and multi-species (Streptococcus mutans, Actinomyces naeslundii, and Streptococcus sanguis) biofilms were grown on acid-etched dentine discs. Biofilms were incubated (120 min/37 °C) and allowed to grow for 3 days anaerobically. Discs (no treatment) served as control (group 1). Groups II, III, IV, and V were then treated with 2% chlorhexidine, and 2%, 5%, and 10% QAS (20 s). Discs were returned to well plates with 300 μL of bacterial suspension and placed in anaerobic incubator at 37 °C and biofilms redeveloped for 4 days. Confocal microscopy, Raman, CFU, and MTT assay were performed.<br><br>RESULTS: Raman peaks show shifts at 1450 cm-1, 1453 cm-1, 1457 cm-1, 1460 cm-1, and 1462 cm-1 for control, 2% CHX, 2%, 5%, and 10% QAS groups in multi-species biofilms. There was reduction of 484 cm-1 band in 10% QAS group. CLSM revealed densely clustered green colonies in control group and red confluent QAS-treated biofilms with significantly lower log CFU for single/dual species. Metabolic activities of Streptococcus mutans and Lactobacillus acidophilus decreased with increasing QAS exposure time.<br><br>CONCLUSION: Quaternary ammonium silanes possess antimicrobial activities and inhibit growth of cariogenic biofilms.<br><br>CLINICAL SIGNIFICANCE: Available data demonstrated use of QAS as potential antibacterial cavity disinfectant in adhesive dentistry. Experimental QAS can effectively eliminate caries-forming bacteria, when used inside a prepared cavity, and can definitely overcome problems associated with present available cavity disinfectants.},
}
@article {pmid31114932,
year = {2019},
author = {Montazeri, A and Salehzadeh, A and Zamani, H},
title = {Effect of silver nanoparticles conjugated to thiosemicarbazide on biofilm formation and expression of intercellular adhesion molecule genes, icaAD, in Staphylococcus aureus.},
journal = {Folia microbiologica},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12223-019-00715-1},
pmid = {31114932},
issn = {1874-9356},
abstract = {Biofilm formation is regarded as an important factor in the establishment of infections caused by Staphylococcus aureus. In the present study, phenotypic and molecular assays were used to evaluate antibiofilm potential of thiosemicarbazide (Tsc) conjugated with silver nanoparticles (Ag NPs) and functionalized by glutamic acid (Ag@Glu/Tsc NPs) against methicillin-resistant S. aureus (MRSA). Ag NPs were synthesized using precipitation method and conjugated to Tsc using glutamic acid. The NPs were characterized using SEM and FTIR spectroscopy analyses. Then, antibiofilm potential of the prepared NPs against MRSA strains was evaluated using phenotypic method and their effects on the expression of biofilm-associated genes icaA and icaD. Finally, the genes involved with the synthesis of intercellular adhesion molecules were determined. According to the results, Ag@Glu/Tsc NPs inhibited biofilm formation of MRSA strains up to 76.7% compared with the control. In addition, expression of the biofilm-associated genes icaA and icaD reduced by 66.7% and 60.3%, respectively in the presence of sub-inhibitory concentration of Ag@Glu/Tsc NPs. In conclusion, Ag@Glu/Tsc NPs could be considered as a potent antibacterial agent to inhibit bacterial biofilms.},
}
@article {pmid31114399,
year = {2019},
author = {Dance, DA and Wuthiekanun, V and Sarovich, D and Price, EP and Limmathurotsakul, D and Currie, BJ and Trung, TT},
title = {Pan-drug-resistant and biofilm-producing strain of Burkholderia pseudomallei: first report of melioidosis from a diabetic patient in Yogyakarta, Indonesia [Letter].},
journal = {International medical case reports journal},
volume = {12},
number = {},
pages = {117-118},
doi = {10.2147/IMCRJ.S205245},
pmid = {31114399},
issn = {1179-142X},
}
@article {pmid31113899,
year = {2019},
author = {Pisithkul, T and Schroeder, JW and Trujillo, EA and Yeesin, P and Stevenson, DM and Chaiamarit, T and Coon, JJ and Wang, JD and Amador-Noguez, D},
title = {Metabolic Remodeling during Biofilm Development of Bacillus subtilis.},
journal = {mBio},
volume = {10},
number = {3},
pages = {},
doi = {10.1128/mBio.00623-19},
pmid = {31113899},
issn = {2150-7511},
abstract = {Biofilms are structured communities of tightly associated cells that constitute the predominant state of bacterial growth in natural and human-made environments. Although the core genetic circuitry that controls biofilm formation in model bacteria such as Bacillus subtilis has been well characterized, little is known about the role that metabolism plays in this complex developmental process. Here, we performed a time-resolved analysis of the metabolic changes associated with pellicle biofilm formation and development in B. subtilis by combining metabolomic, transcriptomic, and proteomic analyses. We report surprisingly widespread and dynamic remodeling of metabolism affecting central carbon metabolism, primary biosynthetic pathways, fermentation pathways, and secondary metabolism. Most of these metabolic alterations were hitherto unrecognized as biofilm associated. For example, we observed increased activity of the tricarboxylic acid (TCA) cycle during early biofilm growth, a shift from fatty acid biosynthesis to fatty acid degradation, reorganization of iron metabolism and transport, and a switch from acetate to acetoin fermentation. Close agreement between metabolomic, transcriptomic, and proteomic measurements indicated that remodeling of metabolism during biofilm development was largely controlled at the transcriptional level. Our results also provide insights into the transcription factors and regulatory networks involved in this complex metabolic remodeling. Following upon these results, we demonstrated that acetoin production via acetolactate synthase is essential for robust biofilm growth and has the dual role of conserving redox balance and maintaining extracellular pH. This report represents a comprehensive systems-level investigation of the metabolic remodeling occurring during B. subtilis biofilm development that will serve as a useful road map for future studies on biofilm physiology.IMPORTANCE Bacterial biofilms are ubiquitous in natural environments and play an important role in many clinical, industrial, and ecological settings. Although much is known about the transcriptional regulatory networks that control biofilm formation in model bacteria such as Bacillus subtilis, very little is known about the role of metabolism in this complex developmental process. To address this important knowledge gap, we performed a time-resolved analysis of the metabolic changes associated with bacterial biofilm development in B. subtilis by combining metabolomic, transcriptomic, and proteomic analyses. Here, we report a widespread and dynamic remodeling of metabolism affecting central carbon metabolism, primary biosynthetic pathways, fermentation pathways, and secondary metabolism. This report serves as a unique hypothesis-generating resource for future studies on bacterial biofilm physiology. Outside the biofilm research area, this work should also prove relevant to any investigators interested in microbial physiology and metabolism.},
}
@article {pmid31113370,
year = {2019},
author = {Liu, X and Yan, Y and Wu, H and Zhou, C and Wang, X},
title = {Biological and transcriptomic studies reveal hfq is required for swimming, biofilm formation and stress response in Xanthomonas axonpodis pv. citri.},
journal = {BMC microbiology},
volume = {19},
number = {1},
pages = {103},
doi = {10.1186/s12866-019-1476-9},
pmid = {31113370},
issn = {1471-2180},
support = {cstc2016shms-ztzx80003//Chongqing Science and Technology Commission/ ; },
abstract = {BACKGROUND: Hfq is a widely conserved bacterial RNA-binding protein which generally mediates the global regulatory activities involv ed in physiological process and virulence. The goal of this study was to characterize the biological function of hfq gene in Xanthomonas axonpodis pv. citri (Xac), the causal agent of citrus canker disease.<br><br>RESULTS: An hfq mutant in Xac was generated by plasmid integration. The loss of hfq resulted in attenuation of bacterial growth, motility and biofilm formation. In addition, the hfq mutation impaired Xac resistance to H2O2 and both high and low pH environments, but did not affect the virulence to citrus. RNA-Seq analyses indicated that Hfq played roles in regulating the expression of 746 genes. In hfq mutant, gene expression related to chemotaxis, secretion system, two-component system, quorum sensing and flagellar assembly were repressed, whereas expression of ribosomal genes were significantly up-regulated. The down-regulated expression of three bacterial chemotaxis related genes and seven flagella genes, which involved in cell growth and biofilm formation, were further validated by RT-qPCR.<br><br>CONCLUSIONS: The study demonstrated that hfq was involved in multiple biological processes in Xac. The results could serve as initiate points for identifying regulatory sRNAs and genes controlled by Hfq-sRNA interactions in Xac.},
}
@article {pmid31112769,
year = {2019},
author = {Jannadi, H and Correa, W and Zhang, Z and Brandenburg, K and Oueslati, R and Rouabhia, M},
title = {Antimicrobial peptides Pep19-2.5 and Pep19-4LF inhibited Streptococcus mutans growth and biofilm formation.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103546},
doi = {10.1016/j.micpath.2019.103546},
pmid = {31112769},
issn = {1096-1208},
abstract = {With this study, we investigated the effect of synthetic antimicrobial peptides Pep19-2.5 and Pep194LF alone or in combination with antibiotics on S. mutans growth and biofilm formation/disruption. We also examined the cytotoxic effect of each peptide on monocytes. S. mutans was cultured in the presence of different concentrations of each peptide. We showed that Pep19-2.5 and Pep19-4LF were able to significantly (p ≤ 0.01) inhibit the growth of S. mutans. The synthetic peptides also decreased biofilm formation by S. mutans. Furthermore, both peptides reduced the viability of S. mutans in already formed biofilms. The combination of each peptide with antibiotics (penicillin/streptomycin, P/S) produced additive interactions which inhibited S. mutans growth and biofilm formation. Pep19-2.5 and Pep19-4LF were nontoxic, as they did not decrease monocyte viability and did not increase the lactate dehydrogenase activity of the exposed cells. In conclusion, synthetic peptides Pep19-2.5 and Pep19-4LF did inhibit S. mutans growth and its capacity to form biofilm. Both peptides were found to be nontoxic to monocytes. These data provide new insight into the efficacy of synthetic peptides Pep19-2.5 and Pep19-4LF against S. mutans. These peptides may thus be useful in controlling the adverse effects of this cariogenic bacterium in human.},
}
@article {pmid31110496,
year = {2019},
author = {Rizzato, C and Torres, J and Kasamatsu, E and Camorlinga-Ponce, M and Bravo, MM and Canzian, F and Kato, I},
title = {Potential Role of Biofilm Formation in the Development of Digestive Tract Cancer With Special Reference to Helicobacter pylori Infection.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {846},
doi = {10.3389/fmicb.2019.00846},
pmid = {31110496},
issn = {1664-302X},
abstract = {Bacteria are highly social organisms that communicate via signaling molecules and can assume a multicellular lifestyle to build biofilm communities. Until recently, complications from biofilm-associated infection have been primarily ascribed to increased bacterial resistance to antibiotics and host immune evasion, leading to persistent infection. In this theory and hypothesis article we present a relatively new argument that biofilm formation has potential etiological role in the development of digestive tract cancer. First, we summarize recent new findings suggesting the potential link between bacterial biofilm and various types of cancer to build the foundation of our hypothesis. To date, evidence has been particularly convincing for colorectal cancer and its precursor, i.e., polyps, pointing to several key individual bacterial species, such as Bacteroides fragilis, Fusobacterium nucleatum, and Streptococcus gallolyticus subsp. Gallolyticus. Then, we further extend this hypothesis to one of the most common bacterial infection in humans, Helicobacter pylori (Hp), which is considered a major cause of gastric cancer. Thus far, there has been no direct evidence linking in vivo Hp gastric biofilm formation to gastric carcinogenesis. Yet, we synthesize the information to support an argument that biofilm associated-Hp is potentially more carcinogenic, summarizing biological characteristics of biofilm-associated bacteria. We also discuss mechanistic pathways as to how Hp or other biofilm-associated bacteria control biofilm formation and highlight recent findings on Hp genes that influence biofilm formation, which may lead to strain variability in biofilm formation. This knowledge may open a possibility of developing targeted intervention. We conclude, however, that this field is still in its infancy. To test the hypothesis rigorously and to link it ultimately to gastric pathologies (e.g., premalignant lesions and cancer), studies are needed to learn more about Hp biofilms, such as compositions and biological properties of extracellular polymeric substance (EPS), presence of non-Hp microbiome and geographical distribution of biofilms in relation to gastric gland types and structures. Identification of specific Hp strains with enhanced biofilm formation would be helpful not only for screening patients at high risk for sequelae from Hp infection, but also for development of new antibiotics to avoid resistance, regardless of its association with gastric cancer.},
}
@article {pmid31109992,
year = {2019},
author = {Berne, C and Brun, YV},
title = {The two chemotaxis clusters in Caulobacter crescentus play different roles in chemotaxis and biofilm regulation.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00071-19},
pmid = {31109992},
issn = {1098-5530},
abstract = {The holdfast polysaccharide adhesin is crucial for irreversible cell adhesion and biofilm formation in Caulobacter crescentus Holdfast production is tightly controlled via developmental regulators, as well as via environmental and physical signals. Here we identify a novel mode of regulation of holdfast synthesis that involves chemotaxis proteins. We characterized the two identified chemotaxis clusters of C. crescentus and showed that only the previously characterized, major cluster is involved in chemotactic response towards different carbon sources. However, both chemotaxis clusters encoded in the C. crescentus genome play a role in biofilm formation and holdfast production, by regulating the expression of hfiA, the gene encoding the holdfast inhibitor HfiA. We show that CheA and CheB proteins act in an antagonistic manner: while the two CheA proteins negatively regulate hfiA expression, the CheB proteins are positive regulators, thus providing a modulation of holdfast synthesis and surface attachment.IMPORTANCEChemosensory systems constitute major signal transduction pathways in bacteria. These systems are involved in chemotaxis and other cell responses to environment conditions, such as production of adhesins to enable irreversible adhesion to a surface and surface colonization. The C. crescentus genome encodes two complete chemotaxis clusters. Here we characterized the second, novel chemotaxis-like cluster. While only the major chemotaxis cluster is involved in chemotaxis, both chemotaxis systems modulate C. crescentus adhesion by controlling expression of the holdfast synthesis inhibitor HfiA. Here, we identify a new level in holdfast regulation, providing new insights into the control of adhesin production that leads to the formation of biofilms in response to the environment.},
}
@article {pmid31107334,
year = {2019},
author = {Stoodley, P},
title = {CORR Insights®: Is Implant Coating With Tyrosol- and Antibiotic-loaded Hydrogel Effective in Reducing Cutibacterium (Propionibacterium) acnes Biofilm Formation? A Preliminary In Vitro Study.},
journal = {Clinical orthopaedics and related research},
volume = {},
number = {},
pages = {},
doi = {10.1097/CORR.0000000000000721},
pmid = {31107334},
issn = {1528-1132},
}
@article {pmid31107198,
year = {2019},
author = {Volejníková, A and Melicherčík, P and Nešuta, O and Vaňková, E and Bednárová, L and Rybáček, J and Čeřovský, V},
title = {Antimicrobial peptides prevent bacterial biofilm formation on the surface of polymethylmethacrylate bone cement.},
journal = {Journal of medical microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1099/jmm.0.001000},
pmid = {31107198},
issn = {1473-5644},
abstract = {PURPOSE: Antibiotic-loaded polymethylmethacrylate-based bone cement has been implemented in orthopaedics to cope with implant-related infections associated with the formation of bacterial biofilms. In the context of emerging bacterial resistance to current antibiotics, we examined the efficacy of short antimicrobial peptide-loaded bone cement in inhibiting bacterial adhesion and consequent biofilm formation on its surface.<br><br>METHODOLOGY: The ability of α-helical antimicrobial peptides composed of 12 amino acid residues to prevent bacterial biofilm [methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Pseudomonas aeruginosa and Escherichia coli] formation on the surface of model implants made from polymethylmethacrylate-based bone cement was evaluated by colony-forming unit (c.f.u.) counting of bacteria released by sonication from the biofilms formed on their surfaces. The biofilms on model implant surfaces were also visualized by light microscopy after staining with tetrazolium dye (MTT) and by scanning electron microscopy.<br><br>RESULTS: When incorporated in the implants, these peptides caused a mean reduction in the number of bacterial cells attached to implants' surfaces (by five orders of magnitude), and 88 % of these implants showed no bacterial adhesion after being exposed to growth media containing various bacteria.<br><br>CONCLUSION: The results showed that the antibiofilm activity of these peptides was comparable to that of the antibiotics, but the peptides exhibited broader specificity than the antibiotics. Given the rapid development of antibiotic resistance, antimicrobial peptides show promise as a substitute for antibiotics for loading into bone cements.},
}
@article {pmid31106716,
year = {2019},
author = {Perez, LRR},
title = {Equal, but different: Fluctuant biofilm formation and its impact on polymyxin B susceptibility among a clonal spreading of KPC-2-producing Klebsiella pneumoniae isolates.},
journal = {Infection control and hospital epidemiology},
volume = {},
number = {},
pages = {1-2},
doi = {10.1017/ice.2019.106},
pmid = {31106716},
issn = {1559-6834},
}
@article {pmid31106237,
year = {2019},
author = {Colomer-Winter, C and Lemos, JA and Flores-Mireles, AL},
title = {Biofilm Assays on Fibrinogen-coated Silicone Catheters and 96-well Polystyrene Plates.},
journal = {Bio-protocol},
volume = {9},
number = {6},
pages = {},
doi = {10.21769/BioProtoc.3196},
pmid = {31106237},
issn = {2331-8325},
abstract = {Biofilm formation is a well-known bacterial strategy that protects cells from hostile environments. During infection, bacteria found in a biofilm community are less sensitive to antibiotics and to the immune response, often allowing them to colonize and persist in the host niche. Not surprisingly, biofilm formation on medical devices, such as urinary catheters, is a major problem in hospital settings. To be able to eliminate such biofilms, it is important to understand the key bacterial factors that contribute to their formation. A common practice in the lab setting is to study biofilms grown in laboratory media. However, these media do not fully reflect the host environment conditions, potentially masking relevant biological determinants. This is the case during urinary catheterization, where a key element for Enterococcus faecalis and Staphylococcus aureus colonization and biofilm formation is the release of fibrinogen (Fg) into the bladder and its deposition on the urinary catheter. To recapitulate bladder conditions during catheter-associated urinary tract infection (CAUTI), we have developed a fibrinogen-coated catheter and 96-well plate biofilm assay in urine. Notably, enterococcal biofilm factors identified in these in vitro assays proved to be important for biofilm formation in vivo in a mouse model of CAUTI. Thus, the method described herein can be used to uncover biofilm-promoting factors that are uniquely relevant in the host environment, and that can be exploited to develop new antibacterial therapies.},
}
@article {pmid31106062,
year = {2019},
author = {Khider, M and Hansen, H and Hjerde, E and Johansen, JA and Willassen, NP},
title = {Exploring the transcriptome of luxI- and ΔainS mutants and the impact of N-3-oxo-hexanoyl-L- and N-3-hydroxy-decanoyl-L-homoserine lactones on biofilm formation in Aliivibrio salmonicida.},
journal = {PeerJ},
volume = {7},
number = {},
pages = {e6845},
doi = {10.7717/peerj.6845},
pmid = {31106062},
issn = {2167-8359},
abstract = {Background: Bacterial communication through quorum sensing (QS) systems has been reported to be important in coordinating several traits such as biofilm formation. In Aliivibrio salmonicida two QS systems the LuxI/R and AinS/R, have been shown to be responsible for the production of eight acyl-homoserine lactones (AHLs) in a cell density dependent manner. We have previously demonstrated that inactivation of LitR, the master regulator of the QS system resulted in biofilm formation, similar to the biofilm formed by the AHL deficient mutant ΔainSluxI- . In this study, we aimed to investigate the global gene expression patterns of luxI and ainS autoinducer synthases mutants using transcriptomic profiling. In addition, we examined the influence of the different AHLs on biofilm formation.<br><br>Results: The transcriptome profiling of ΔainS and luxI- mutants allowed us to identify genes and gene clusters regulated by QS in A. salmonicida. Relative to the wild type, the ΔainS and luxI- mutants revealed 29 and 500 differentially expressed genes (DEGs), respectively. The functional analysis demonstrated that the most pronounced DEGs were involved in bacterial motility and chemotaxis, exopolysaccharide production, and surface structures related to adhesion. Inactivation of luxI, but not ainS genes resulted in wrinkled colony morphology. While inactivation of both genes (ΔainSluxI-) resulted in strains able to form wrinkled colonies and mushroom structured biofilm. Moreover, when the ΔainSluxI- mutant was supplemented with N-3-oxo-hexanoyl-L-homoserine lactone (3OC6-HSL) or N-3-hydroxy-decanoyl-L-homoserine lactone (3OHC10-HSL), the biofilm did not develop. We also show that LuxI is needed for motility and for repression of EPS production, where repression of EPS is likely operated through the RpoQ-sigma factor.<br><br>Conclusion: These findings imply that the LuxI and AinS autoinducer synthases play a critical role in the regulation of biofilm formation, EPS production, and motility.},
}
@article {pmid31105285,
year = {2019},
author = {Samad, A and Khan, AA and Sajid, M and Zahra, R},
title = {Assessment of biofilm formation by pseudomonas aeruginosa and hydrodynamic evaluation of microtiter plate assay.},
journal = {JPMA. The Journal of the Pakistan Medical Association},
volume = {69},
number = {5},
pages = {666-671},
pmid = {31105285},
issn = {0030-9982},
abstract = {OBJECTIVE: To assess the biofilm formation in clinical and environmental isolates of Pseudomonas aeruginosa and to evaluate the hydrodynamics in microtiter plate assay and compare it with conventional assays for biofilm formation.<br><br>METHODS: The cross-sectional study was conducted at the Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan, in 2013-14, while the computational work was done at the National University of Science and Technology, Islamabad. The study comprised environmental and clinical isolates of pseudomonas aeruginosa. Pseudomonas citramide agar was used as a selective media, and further confirmation was done by biochemical tests. Biofilm formation was assessed by Congo red assay, air liquid interfaceassay and microtiter plate assay. Computational Fluid Dynamics (CFD) simulations were also used to improve the microtiter plate assay for biofilm formation assessment. Polymerase chain reaction was used for screening of pelA and pelG genes.<br><br>RESULTS: Of the 50 isolates, 25(50%) each were environmental and clinical. The number of biofilm producers observed in Congo red assay, air liquid interface assay and microtiter plate assay were 7(14%), 15(30%) and 30(60%) respectively. Biofilm former gene pelA was observed in 22(44%) isolates while 36(72%) isolates showed the presence of pelG gene.<br><br>CONCLUSIONS: Microtiter plate assay was found to be a reliable method to detect biofilm forming pseudomonas aeruginosa isolates which further provides a base for development of methods to detect biofilms readily and accurately.},
}
@article {pmid31104214,
year = {2019},
author = {Aiyer, KS and Vijayakumar, BS},
title = {An improvised microtiter dish biofilm assay for non-invasive biofilm detection on microbial fuel cell anodes and studying biofilm growth conditions.},
journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]},
volume = {},
number = {},
pages = {},
doi = {10.1007/s42770-019-00091-5},
pmid = {31104214},
issn = {1678-4405},
abstract = {Microbial life is predominantly observed as biofilms, which are a sessile aggregation of microbial cells formed in response to stress conditions. The microtiter dish biofilm formation assay is one of the most important methods of studying biofilm formation. In this study, the assay has been improvised to allow easy detection of biofilm formation on different substrata. The method has then been used to study growth conditions that affect biofilm formation, viz., the effect of pH, temperature, shaking conditions, and the carbon source provided. Glass, cellulose acetate, and carbon cloth materials were used as substrata to study biofilm development under the above conditions. The method was then extended to determine biofilm formation on the anodes of a microbial fuel cell in order to study the effect of biofilm formation on power production. A high correlation was observed between biofilm formation and power density (r = 0.951). When the electrode containing a biofilm was replaced with another electrode without biofilm, the average power density dropped from 59.55 to 5.76 mW/m2. This method offers an easy way to study the suitability of different materials to support biofilm formation. Growth conditions determining biofilm formation can be studied using this method. This method also offers a non-invasive way to determine biofilm formation on anodes of microbial fuel cells and preserves the anode for further studies.},
}
@article {pmid31102859,
year = {2019},
author = {Liang, C and Zhang, L and Nord, NB and Carvalho, PN and Bester, K},
title = {Dose-dependent effects of acetate on the biodegradation of pharmaceuticals in moving bed biofilm reactors.},
journal = {Water research},
volume = {159},
number = {},
pages = {302-312},
doi = {10.1016/j.watres.2019.04.026},
pmid = {31102859},
issn = {1879-2448},
abstract = {Moving bed biofilm reactors (MBBR) are promising as a post-treatment for removing pharmaceuticals from wastewater. However, the effect of easily degradable carbon sources on the degradation of pharmaceuticals is unclear. This study shows the influence of acetate on the degradation of 26 pharmaceuticals in an MBBR was dose- and compound-dependent: while the degradation of venlafaxine, tramadol and ciprofloxacin was promoted (increase of reaction rate constant (k) by 133%, 212%, 55%) by acetate, its presence caused negative effects on the removal of ibuprofen, citalopram and diclofenac (decrease of k by 76%, 57%, 44%). The deconjugation of acetyl-sulfadiazine was clearly slowed down (decrease of k by 75%) by the dosed acetate, probably due to feedback inhibition by abundant acetate. 17 out of 25 tested compounds were found to be independent of the acetate dosage, which suggested dosing acetate induced minor effects on most of pharmaceuticals' removal. Enrichment of S- or first eluted enantiomer of 4 β-blockers and the metabolite metoprolol acid was observed. Both non-enantioselective (rapid at elevated compound concentration) and enantioselective enzymes (slower and predominant at lower compound concentration) played a part in the biodegradation. High doses of acetate slowed down the enantiomeric enrichment of atenolol, metoprolol, propranolol and metoprolol acid, which demonstrated that the acetate is able to up- or down-regulate enzymes involved in the enantioselective degradation of β-blockers and thus reveals a complex co-metabolism relationship between transformation pathways of pharmaceuticals and carbon source.},
}
@article {pmid31102615,
year = {2019},
author = {Campbell, M and Zhao, W and Fathi, R and Mihreteab, M and Gilbert, ES},
title = {Title:Rhamnus prinoides (gesho): A source of diverse anti-biofilm activity.},
journal = {Journal of ethnopharmacology},
volume = {},
number = {},
pages = {111955},
doi = {10.1016/j.jep.2019.111955},
pmid = {31102615},
issn = {1872-7573},
abstract = {Rhamnus prinoides (gesho) is an evergreen shrub from East Africa traditionally used for the treatment of illnesses including atopic dermatitis, ear, nose and throat infections, pneumonia, arthritis, brucellosis, flu, indigestion and fatigue.<br><br>AIM OF THE STUDY: Several of the conditions for which gesho is traditionally used are associated with communities of surface-attached microorganisms, or biofilms. We hypothesized that gesho has anti-biofilm activity. The principal aim of this study was to evaluate gesho-associated anti-biofilm activity and identify active compounds.<br><br>MATERIALS AND METHODS: Lyophilized ethanol and aqueous extracts were prepared from dried Rhamnus prinoides stems and leaves. Biofilm inhibition was measured by crystal violet staining and subsequent viability assays were conducted on growth agar. Chemical fractionation, chemical testing, Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) were used to isolate and identify active compounds.<br><br>RESULTS: Leaf and stem ethanol extracts significantly inhibited Staphylococcus aureus, Bacillus subtilis and Streptococcus mutans biofilm formation up to 99.9% and reduced planktonic cell growth up to 10 log units relative to untreated controls. The anti-biofilm activity of the ethanol stem extracts was due to a biocidal or bacteriostatic mechanism while bacteriostatic or anti-pathogenic mechanisms were attributed to the leaf ethanol extract. Gesho extracts showed activity against all three species tested but the treatment efficacy and mechanism were species dependent. Chemical fractionation and activity screens of the leaf ethanol extract identified ethyl 4-ethoxybenzoate and 4-hydroxy 4-methyl pentanone to be compounds with anti-biofilm activity. Ethyl 4-ethoxybenzoate activity was potentiated by DMSO. Notably, concentrations of both compounds were identified where biofilm formation was prevented without inhibition of cell growth; i.e. anti-pathogenic characteristics were evident.<br><br>CONCLUSION: Gesho leaf ethanol extract contains chemicals with anti-biofilm and bactericidal activities. This work lends support to the traditional use of gesho for treating topical infections and warrants further investigation into Rhamnus prinoides as a source of antibacterial and anti-biofilm agents.},
}
@article {pmid31102398,
year = {2019},
author = {Carvajal, J and Carvajal, M},
title = {Further Clarification About &quot;Back to Basics: Could the Preoperative Skin Antiseptic Agent Help Prevent Biofilm-Related Capsular Contracture?&quot;.},
journal = {Aesthetic surgery journal},
volume = {},
number = {},
pages = {},
doi = {10.1093/asj/sjz076},
pmid = {31102398},
issn = {1527-330X},
}
@article {pmid31100490,
year = {2019},
author = {Senpuku, H and Mohri, S and Mihara, M and Arai, T and Suzuki, Y and Saeki, Y},
title = {Effects of 7S globulin 3 derived from the adzuki bean [Vigna angularis] on the CSP- and eDNA- dependent biofilm formation of Streptococcus mutans.},
journal = {Archives of oral biology},
volume = {102},
number = {},
pages = {256-265},
doi = {10.1016/j.archoralbio.2019.04.010},
pmid = {31100490},
issn = {1879-1506},
abstract = {OBJECTIVE: Streptococcus mutans is a principal bacterium that forms pathogenic biofilm involved in the development of dental caries. S. mutans possesses a quorum sensing system (QS) stimulated by competence stimulating peptide (CSP), which is associated with bacteriocin production, genetic competency and biofilm formation. Inhibiting CSP-dependent QS is one of the aims leading to the inhibition of biofilm formation and is useful for establishing new prevention systems for dental caries.<br><br>DESIGN: In this study, we selected adzuki bean [Vigna angularis] extract as a candidate component to inhibit CSP-dependent biofilm formation among various foods. To purify an inhibitory component from the adzuki extracts, we performed the salting-out method, two rounds of ion-exchange chromatography, and SDS and native PAGE.<br><br>RESULTS: A primary protein band that inhibits CSP-dependent biofilm formation appeared at approximately 50 kDa and was identified as 7S globulin 3 (7S3), a major seed storage protein in adzuki bean. To determine the characteristics of 7S3 as an inhibitory component, aggregated proteins were extracted from the adzuki crude extracts at pH values lower than 6. The aggregated proteins inhibited CSP- and eDNA-dependent biofilm formation and showed 50 kDa band, which is identical with 7S3 in the purified sample. Moreover, 7S globulin 3 in the adzuki bean extract directly interacted with CSP at low pH conditions but not at neutral conditions, and inhibited CSP-dependent bacteriocin production.<br><br>CONCLUSION: It was suggested that 7S3 might be a safe and useful material to prevent pathogenic activities in the biofilm formation of S. mutans.},
}
@article {pmid31100153,
year = {2019},
author = {Lin, CJ and Hou, YH and Chen, YL},
title = {The histone acetyltransferase GcnE regulates conidiation and biofilm formation in Aspergillus fumigatus.},
journal = {Medical mycology},
volume = {},
number = {},
pages = {},
doi = {10.1093/mmy/myz043},
pmid = {31100153},
issn = {1460-2709},
abstract = {Histone modifications play a crucial role in eukaryotic gene regulation. The Spt-Ada-Gcn5-acetyltransferase (SAGA) complex controls histone acetylation, with Gcn5 (GcnE) acting as the acetyltransferase. In the Aspergillus species, GcnE has been shown to regulate asexual development and secondary metabolism. Apart from this, GcnE is required for pathogenicity in plant fungal pathogen A. flavus; however, the role of GcnE in the pathogenicity of human pathogenic fungus A. fumigatus is unknown. In this study, we uncovered the key roles of GcnE in A. fumigatus conidiation, stress responses, and biofilm formation. We observed that deletion of gcnE resulted in aberrant conidiation in which conidiophores displayed abnormal phialide formation. In addition, the ΔgcnE mutant grew slightly faster under limited nitrogen sources (1 mM of ammonium or nitrate) compared to the wild type. The ΔgcnE mutant exhibited increased susceptibility to cell wall-perturbing agents, H2O2 and menadione but enhanced tolerance to LiCl. Furthermore, we showed that GcnE is involved in biofilm formation, and overexpression of adherence-related genes such as somA or uge3 partially rescued biofilm formation defects in the ΔgcnE mutant background. Interestingly, GcnE was not required for virulence in a neutropenic murine model of invasive aspergillosis. These results suggest that GcnE is critical for conidiation and biofilm formation but not virulence in A. fumigatus.},
}
@article {pmid31099708,
year = {2019},
author = {Sato, A and Yamaguchi, T and Hamada, M and Ono, D and Sonoda, S and Oshiro, T and Nagashima, M and Kato, K and Okazumi, S and Katoh, R and Ishii, Y and Tateda, K},
title = {Morphological and Biological Characteristics of Staphylococcus aureus Biofilm Formed in the Presence of Plasma.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2019.0068},
pmid = {31099708},
issn = {1931-8448},
abstract = {Characteristics of Staphylococcus aureus infections include biofilm formation, leading to the spread of bacteria to the bloodstream causing sepsis and metastatic infections. In particular, in methicillin-resistant S. aureus (MRSA) infections, biofilm formation critically hampers treatment and causes poor prognosis. We explored the biofilm formation of MRSA in the presence or absence of plasma and compared morphological characteristics, accumulation of antibiotics, and resistance to bactericidal activity, using continuous optimizing confocal reflection microscopy. Addition of plasma significantly increased biofilm formation, which is characterized by an uneven surface and aggregation of bacteria (hereafter plasma biofilm). The flow-cell system, which enabled a continuous supply of plasma, accelerated biofilm formation in both the tested strains of MRSA (BAA1556 and N315). Accumulation of green fluorescence-labeled vancomycin was observed within 5 minutes in the plasma-free biofilm, but not in the plasma biofilm. Delay of accumulation was also observed for daptomycin in plasma biofilm. Plasma biofilm bacteria were more resistant to anti-MRSA antibiotics than plasma-free biofilm bacteria. These data demonstrate that the plasma biofilm of S. aureus is substantially different from the plasma-free biofilm. Plasma biofilm, especially in the flow-cell system, could be a clinically relevant model to analyze MRSA infections and treatment.},
}
@article {pmid31099211,
year = {2018},
author = {André, CB and Chan, DC and Giannini, M},
title = {Antibacterial-containing dental adhesives' effects on oral pathogens and on Streptococcus mutans biofilm: Current perspectives.},
journal = {American journal of dentistry},
volume = {31},
number = {Sp Is B},
pages = {37B-41B},
pmid = {31099211},
issn = {0894-8275},
abstract = {PURPOSE: To describe the literature findings regarding commercially available antibacterial-containing dental adhesives and the futures perspectives of this field.<br><br>RESULTS: High-risk caries patients could yield benefits from restorative materials containing antibacterial properties in order to reduce the recurrent caries formation. Dental adhesives with antibacterial agents may reduce restoration replacement, as recurrent caries is still one of the major reasons for replacing a resin restoration. Literature results of three commercially available adhesives: Gluma 2Bond, Clearfil SE Protect and Peak Universal Bond, containing glutaraldehyde, MDPB and chlorhexidine, respectively indicates that Clearfil SE Protect seems to have better results against oral pathogens and on Streptococcus mutans biofilm. Besides the promising findings, clinical studies are still necessary in order to validate the clinical efficacy when exposed to a more complex environment and the long-term effect of either commercially available materials, experimental antibacterial monomers or antibacterial incorporations. As a suggestion of this article and according to the current scientific trends in this specific field, future directions should focus on restorative materials with therapeutic components targeting the virulence factors of cariogenic biofilm with minimal toxicity and side effects, and long-term action.<br><br>CLINICAL SIGNIFICANCE: Antibacterial-containing dental adhesives may have therapeutic effects, working as an additional source to reduce recurrent caries development in patients with high-risk of caries, and consequently the reduction in restoration replacements.},
}
@article {pmid31099066,
year = {2019},
author = {Ali, SE and Songe, MM and Skaar, I},
title = {Colorimetric assay for the in vitro evaluation of Saprolegnia biofilm inhibitors.},
journal = {Journal of fish diseases},
volume = {},
number = {},
pages = {},
doi = {10.1111/jfd.13017},
pmid = {31099066},
issn = {1365-2761},
support = {238550//European Commission through the EU Marie Curie ITN project and CGIAR Research Program on Fish Agri-Food Systems (FISH). SAPRO/ ; },
abstract = {A quantitative and reproducible 96-well microtiter method that is easily adaptable for the screening of Saprolegnia biofilm inhibitors is described. As opposed to other methods previously developed for the screening of Saprolegnia inhibitors on spore germination or mycelial growth, this technique is of particular significance as it investigates potential inhibitors against surface-attached mycelial mats of Saprolegnia spp. (biofilm). In this study, we have investigated the effects of propionic acid (PPA) on reducing the viability of induced Saprolegnia biofilms using colorimetric MTS assay based on the reduction of tetrazolium salts. Viability of Saprolegnia hyphae in treated biofilms was reduced significantly following treatment with different PPA concentrations. The effect was enhanced after combining each of the tested PPA concentrations with 500 mg/L of boric acid (BA). However, the percentage of non-viable hyphae was still higher in 200 mg L-1 bronopol-treated biofilms (positive control) following 6- and 12-hr exposure. Similar results were observed using other recently described fluorescence-based assays for viability.},
}
@article {pmid31098293,
year = {2019},
author = {Dubois, T and Tremblay, YDN and Hamiot, A and Martin-Verstraete, I and Deschamps, J and Monot, M and Briandet, R and Dupuy, B},
title = {A microbiota-generated bile salt induces biofilm formation in Clostridium difficile.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {14},
doi = {10.1038/s41522-019-0087-4},
pmid = {31098293},
issn = {2055-5008},
abstract = {Clostridium difficile is a major cause of nosocomial infections. Bacterial persistence in the gut is responsible for infection relapse; sporulation and other unidentified mechanisms contribute to this process. Intestinal bile salts cholate and deoxycholate stimulate spore germination, while deoxycholate kills vegetative cells. Here, we report that sub-lethal concentrations of deoxycholate stimulate biofilm formation, which protects C. difficile from antimicrobial compounds. The biofilm matrix is composed of extracellular DNA and proteinaceous factors that promote biofilm stability. Transcriptomic analysis indicates that deoxycholate induces metabolic pathways and cell envelope reorganization, and represses toxin and spore production. In support of the transcriptomic analysis, we show that global metabolic regulators and an uncharacterized lipoprotein contribute to deoxycholate-induced biofilm formation. Finally, Clostridium scindens enhances biofilm formation of C. difficile by converting cholate into deoxycholate. Together, our results suggest that deoxycholate is an intestinal signal that induces C. difficile persistence and may increase the risk of relapse.},
}
@article {pmid31097723,
year = {2019},
author = {Passos da Silva, D and Matwichuk, ML and Townsend, DO and Reichhardt, C and Lamba, D and Wozniak, DJ and Parsek, MR},
title = {The Pseudomonas aeruginosa lectin LecB binds to the exopolysaccharide Psl and stabilizes the biofilm matrix.},
journal = {Nature communications},
volume = {10},
number = {1},
pages = {2183},
doi = {10.1038/s41467-019-10201-4},
pmid = {31097723},
issn = {2041-1723},
support = {5R01AI077628//U.S. Department of Health &amp; Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; W911NF1810254//United States Department of Defense | United States Army | Army Medical Command | U.S. Army Research Institute of Environmental Medicine (United States Army Research Institute of Environmental Medicine)/ ; R01 AI134895//Division of Intramural Research, National Institute of Allergy and Infectious Diseases (Division of Intramural Research of the NIAID)/ ; },
abstract = {Pseudomonas aeruginosa biofilms are composed of exopolysaccharides (EPS), exogenous DNA, and proteins that hold these communities together. P. aeruginosa produces lectins LecA and LecB, which possess affinities towards sugars found in matrix EPS and mediate adherence of P. aeruginosa to target host cells. Here, we demonstrate that LecB binds to Psl, a key matrix EPS, and this leads to increased retention of both cells and EPS in a growing biofilm. This interaction is predicted to occur between the lectin and the branched side chains present on Psl. Finally, we show that LecB coordinates Psl localization in the biofilm. This constitutes a unique function for LecB and identifies it as a matrix protein that contributes to biofilm structure through EPS interactions.},
}
@article {pmid31096414,
year = {2019},
author = {Oprei, A and Zlatanović, S and Mutz, M},
title = {Grazers superimpose humidity effect on stream biofilm resistance and resilience to dry-rewet stress.},
journal = {The Science of the total environment},
volume = {659},
number = {},
pages = {841-850},
doi = {10.1016/j.scitotenv.2018.12.316},
pmid = {31096414},
issn = {1879-1026},
abstract = {Temperate low order streams increasingly experience intermittency and drying due to climate change. In comparison to well-studied Mediterranean streams, drying events in canopied temperate streams occur under higher ambient humidity which probably affects the metabolic response to drying. Previous work on drying sediments (in temperate streams) did not consider the interactions of trophic levels. We hypothesized that preservation of sediment moisture due to high humidity increases resistance to drying in temperate streambed biofilms and fast resilience of biofilm activity after flow resumption. We also expected the presence of macroinvertebrate grazers to modulate the biofilm response to dry-rewet stress. Following a two-level factorial design in 24 microcosms, we tested the effect of drying intensity (moderate and intense) and grazer presence and absence (P. antipodarum) on the activity of biofilm colonizing shallow hyporheic sediment. We measured the community respiration over a drying period of 27 days, a single rewetting event and a follow-up of three days. Grazer presence stimulated biofilm community respiration (CRmic) in the permanently wet control, but decreased biofilm resistance to desiccation (<0.2% of pre-disturbed activity), regardless of drying intensity. In the absence of grazers, higher atmospheric humidity in moderately drying microcosms resulted in maintaining a film of adhesive water and low CRmic (29% of pre-disturbed respiration) until the end of the drying period. After flow resumption, the CRmic increased within 8 h, achieving 79-83% of pre-disturbed respiration (no grazers) and 15-41% (with grazers), respectively. Results show that short dry periods in temperate streams, even under high humidity, impact the streambed biofilm community negatively. The complex response and strong effect of grazer presence indicates that experiments including interactions of trophic levels and settings mimicking environmental factors during dry-rewet stress are needed.},
}
@article {pmid31096410,
year = {2019},
author = {Ramírez-Vargas, CA and Arias, CA and Carvalho, P and Zhang, L and Esteve-Núñez, A and Brix, H},
title = {Electroactive biofilm-based constructed wetland (EABB-CW): A mesocosm-scale test of an innovative setup for wastewater treatment.},
journal = {The Science of the total environment},
volume = {659},
number = {},
pages = {796-806},
doi = {10.1016/j.scitotenv.2018.12.432},
pmid = {31096410},
issn = {1879-1026},
abstract = {Constructed wetlands (CWs) performance enhancement can be done with intensification strategies. A recent strategy still in study is the coupling with Microbial Electrochemical Technologies (MET). An alternative system using electro-conductive biofilters instead of electrodes and circuits used in MET, resulted in the development of a Microbial Electrochemical-based CW (METland). This system relies on electroactive bacteria (EAB) metabolism to transfer electrons to an electro-conductive material, thus boosting substrate consumption, and diminishing electron availability for biomass build-up and methane generation. In previous studies this biofilters have shown an improvement in biodegradation rates in comparison with subsurface flow CW. However, this set-up is still in development, hence there are uncertainties regarding the dynamics involve in the removal of pollutants. Considering that, this work aimed at establishing the capacity and removal kinetics of organic matter and nutrients in an Electroactive Biofilm-Based CW (EABB-CW). Two electro-conductive materials were tested (PK-A and PK-LSN) in planted and non-planted mesocosms and compared with sand. The systems were operated in a continuous upflow mode for 32 weeks and fed with real wastewater. The electro-conductive systems reached removal efficiencies up to 88% for BOD5, 90% for COD, 46% for NH4-N, and 86% for PO4-P. Organic matter removal in electro-conductive systems was possible even at loading rates 10-fold higher than recommended for horizontal flow CWs. First-order area-based removal constants (k), calculated for organic matter and nutrients are higher than values typically reported for saturated CW and in certain cases comparable with vertical flow CW. The organic removal was correlated with electron current densities measures, as indicator of the presence of EAB. The tested EABB-CW profiles as a promising CW type for the removal of organic matter and PO4-P with margin for modifications to improve nitrogen removal. Future studies with pilot/real scale systems are proposed to validate the findings of this study.},
}
@article {pmid31095299,
year = {2019},
author = {Hogan, S and Kasotakis, E and Maher, S and Cavanagh, B and O'Gara, JP and Pandit, A and Keyes, TE and Devocelle, M and O'Neill, E},
title = {A novel medical device coating prevents Staphylococcus aureus biofilm formation on medical device surfaces.},
journal = {FEMS microbiology letters},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsle/fnz107},
pmid = {31095299},
issn = {1574-6968},
abstract = {Prevention of device related infections due to Staphylococcus aureus biofilms on devices represents a significant challenge. Such infections have recently been shown to be dependent on the coagulation pathway via activation of pro-thrombin and fibrin production. Three direct-thrombin inhibitors, argatroban, hirudin and dabigatran, were examined to determine their effect on preventing S. aureus biofilm on plastic biochip surfaces under shear stress using an in vivo relevant model of infection. Surface functionalization of polyurethane discs via dityrosine covalent crosslinking with hirudin was performed and changes in bacterial density and microscopic appearances determined. The three direct-thrombin inhibitors prevented S. aureus biofilm formation on plasma-coated surfaces treated with these agents. Coating of polyurethane with one of these agents, hirudin, significantly inhibited biofilm formation on the modified surface. These findings reveal the exciting potential for coating biomaterial surfaces with direct thrombin inhibitors to prevent staphylococcal binding and subsequent device-related infections.},
}
@article {pmid31093442,
year = {2019},
author = {Reda, FM},
title = {Antibacterial and anti-adhesive efficiency of Pediococcus acidilactici against foodborne biofilm producer Bacillus cereus attached on different food processing surfaces.},
journal = {Food science and biotechnology},
volume = {28},
number = {3},
pages = {841-850},
doi = {10.1007/s10068-018-0518-7},
pmid = {31093442},
issn = {2092-6456},
abstract = {This study aimed to assess the biofilm formation by Bacillus cereus on two novel surfaces namely: aluminum and cold steel in comparison study with stainless steel and polystyrene. Also, it aimed to study the inhibitory effect of a new strain Pediococcus acidilactici against biofilm formation by B. cereus grown on these surfaces. In this study, B. cereus M50 isolated from milky machine surface was selected as the highest biofilm producer. The number of M50 cells adhered to aluminum and stainless steel surfaces were more than that adhered to polystyrene and cold steel, respectively. The antimicrobial, anti-adhesive and SEM studies revealed that the P. acidilactici P12 culture and its cell free filtrate showed a significant potential inhibition of biofilm formation of M50 on all tested surfaces under different conditions. These results demonstrated that P. acidilactici strain are considered a new biotreatment for biofilm destruction of food borne pathogens, food biopreservation and food safety.},
}
@article {pmid31091746,
year = {2019},
author = {Yang, CH and Su, PW and Moi, SH and Chuang, LY},
title = {Biofilm Formation in Acinetobacter Baumannii: Genotype-Phenotype Correlation.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {10},
pages = {},
doi = {10.3390/molecules24101849},
pmid = {31091746},
issn = {1420-3049},
support = {106-2221-E-214-043, 107-2221-E-214-013 and 106-2221-E-151-009-MY2//Ministry of Science and Technology/ ; },
abstract = {Strains of Acinetobacter baumannii are commensal and opportunistic pathogens that have emerged as problematic hospital pathogens due to its biofilm formation ability and multiple antibiotic resistances. The biofilm-associated pathogens usually exhibit dramatically decreased susceptibility to antibiotics. This study was aimed to investigate the correlation of biofilm-forming ability, antibiotic resistance and biofilm-related genes of 154 A. baumannii isolates which were collected from a teaching hospital in Taiwan. Biofilm-forming ability of the isolates was evaluated by crystal violet staining and observed by scanning electron microscopy. Antibiotic susceptibility was determined by disc diffusion method and minimum inhibitory concentration; the biofilm-related genes were screened by polymerase chain reaction. Results showed that among the 154 tested isolates, 15.6% of the clinical isolates were weak biofilm producers, while 32.5% and 45.4% of them possessed moderate and strong biofilm formation ability, respectively. The experimental results revealed that the multiple drug resistant isolates usually provided a higher biofilm formation. The prevalence of biofilm related genes including bap, blaPER-1, csuE and ompA among the isolated strains was 79.2%, 38.3%, 91.6%, and 68.8%, respectively. The results indicated that the antibiotic resistance, the formation of biofilm and the related genes were significantly correlated. The results of this study can effectively help to understand the antibiotic resistant mechanism and provides the valuable information to the screening, identification, diagnosis, treatment and control of clinical antibiotic-resistant pathogens.},
}
@article {pmid31084051,
year = {1993},
author = {Mosteller, TM and Bishop, JR},
title = {Sanitizer Efficacy Against Attached Bacteria in a Milk Biofilm.},
journal = {Journal of food protection},
volume = {56},
number = {1},
pages = {34-41},
doi = {10.4315/0362-028X-56.1.34},
pmid = {31084051},
issn = {1944-9097},
abstract = {Pseudomonas fluorescens , Yersinia enterocolitica , and Listeria monocytogenes were shown to readily attach to both rubber and Teflon® surfaces. Sanitizer efficacy testing done in the laboratory with nonadherent bacteria could lead to false assumptions as to the sanitizer's true effectiveness under processing conditions where cells may be attached. The objectives in this study were: (a) evaluate the efficacy of in-use concentrations of sanitizers on bacteria attached to gasket materials, (b) compare bacterial attachment to rubber and Teflon® gaskets, (c) examine different methods of enumeration, and (d) compare sanitizer efficacy on attached and suspended bacteria. The goal reduction for all of the sanitizers tested was ≥3 log cycles or 99.9%. Results indicated that iodophor, hypochlorite, acid anionic, peroxyacetic acid, fatty acid, and quaternary ammonium sanitizers failed to provide an adequate reduction in the numbers of attached bacteria at levels of 104 to 105/mm2 in most cases. The test organisms attached in slightly higher numbers to the rubber surface versus Teflon®. Plate counts, impedance microbiology, and the direct epifluorescent filter technique were tested as methods of enumeration. Impedance microbiology was the best method of enumeration, since it allowed the estimation of both reversibly and irreversibly attached bacteria. The efficacy of sanitizers versus a bacterial suspensions resulted in a ≥ 5 log-cycle reduction. The same concentrations were relatively ineffective against the attached bacteria. The goal reduction was reached on the Teflon® surface with the iodophor, hypochlorite, and fatty acid sanitizers with a log-cycle reduction in the number of Yersinia enterocolitica of 3.09, 3.19, and 3.31, respectively. Pseudomonas fluorescens was reduced by 3.16 on both the rubber and Teflon® surfaces when exposed to the hypochlorite sanitizer.},
}
@article {pmid31088936,
year = {2019},
author = {Tobudic, S and Kern, S and Kussmann, M and Forstner, C and Burgmann, H},
title = {Effect of Peritoneal Dialysis Fluids on Activity of Teicoplanin Against Methicillin-Resistant Staphylococcus aureus Biofilm.},
journal = {Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis},
volume = {39},
number = {3},
pages = {293-294},
doi = {10.3747/pdi.2018.00168},
pmid = {31088936},
issn = {1718-4304},
}
@article {pmid31088182,
year = {2019},
author = {Čabarkapa, I and Čolović, R and Đuragić, O and Popović, S and Kokić, B and Milanov, D and Pezo, L},
title = {Anti-biofilm activities of essential oils rich in carvacrol and thymol against Salmonella Enteritidis.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-15},
doi = {10.1080/08927014.2019.1610169},
pmid = {31088182},
issn = {1029-2454},
abstract = {The aim of the present study was to determine the bioactive compounds in four essential oils (EO's) from Origanum heracleoticum, Origanum vulgare, Thymus vulgaris and Thymus serpyllum and to assess their antimicrobial and anti-biofilm activity against Salmonella Enteritidis. Strains were previously characterized depending on the expression of the extracellular matrix components cellulose and curli fimbriae as rdar (red, dry and rough) and bdar morphotype (brown, dry and rough). This study revealed that the EO's and EOC's (carvacrol and thymol) investigated showed inhibition of biofilm formation at sub-minimum inhibitory concentration. Comparing the efficacy of EO's and EOC's in the inhibition of biofilm formation between the strains with different morphotype (rdar and bdar) did not show a statistically significant difference. Results related to the effectiveness of EO's and EOC's (the essential oil components, carvacrol and thymol) on eradication of preformed 48 h old biofilms indicated that biofilm reduction occurred in a dose-dependent manner over time.},
}
@article {pmid31088179,
year = {2019},
author = {Bernard, C and Lemoine, V and Hoogenkamp, MA and Girardot, M and Krom, BP and Imbert, C},
title = {Candida albicans enhances initial biofilm growth of Cutibacterium acnes under aerobic conditions.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-11},
doi = {10.1080/08927014.2019.1608966},
pmid = {31088179},
issn = {1029-2454},
abstract = {Candida albicans and Cutibacterium acnes are opportunistic pathogens that co-colonize the human body. They are involved in biofilm-related infections of implanted medical devices. The objective of this study was to evaluate the ability of these species to interact and form polymicrobial biofilms. SEM imaging and adhesion assays showed that C. acnes adhesion to C. albicans did not have a preference for a specific morphological state of C. albicans; bacteria adhered to both hyphal and yeast forms of C. albicans. C. albicans did not influence growth of C. acnes under anaerobic growth conditions, however under aerobic growth condition, C. albicans enhanced early C. acnes biofilm formation. This favorable impact of C. albicans was not mediated by secreted compounds accumulating in the medium, but required the presence of metabolically active C. albicans. The ability of these microorganisms to interact together could modulate the physiopathology of infections.},
}
@article {pmid31087992,
year = {2019},
author = {Fu, KM and Liao, MH and Zhou, HT and Fu, C and Jiang, S and Qiu, FG and Cao, XQ},
title = {[Operation Characteristics of the Biofilm CANON Reactor During the Temperature Reduction Process].},
journal = {Huan jing ke xue= Huanjing kexue},
volume = {40},
number = {3},
pages = {1412-1418},
doi = {10.13227/j.hjkx.201808184},
pmid = {31087992},
issn = {0250-3301},
abstract = {The focus of this paper, was low temperature, high ammonia nitrogen wastewater. The operation characteristics of the biofilm CANON process during the temperature reduction process were determined, by continuously adjusting different operating conditions. The aim was to explore the methods needed for the CANON process to obtain stable shortcut nitrification and a good nitrogen removal effect, when the influent NH4+-N concentration is high and the temperature low. The results showed that, ① compared with the biofilm CANON reactor temperature changing from medium to low temperature directly (30℃±1℃→19℃), it was more conducive to adapt the nitrogen-removing bacteria to the low-temperature environment, while the temperature was gradually lowered. Moreover, the extent of each reduction should be minimized. Besides, the operating conditions should be adjusted to ensure the nitrogen removal effect. ② The temperature was gradually reduced to about 19℃ after 25 d, and then decreased to about 15℃ after another 18 d. The NH4+-N and TN removal rates could be respectively stable at 90% and 70% over a long period of time. The TN removal rate and removal load could still reach 72.52% and 0.78 kg·(m3·d)-1, respectively, even when the temperature dropped to 12℃. ③ When adapting biological CANON sludge during the temperature reduction process, shortcut nitrification should be given priority. A stable shortcut nitrification effect should be obtained by maintaining a certain concentration of residual NH4+-N, and by strictly controlling the DO concentration to restrain NOB activity.},
}
@article {pmid31087603,
year = {2019},
author = {Zhu, L and Gong, T and Wood, TL and Yamasaki, R and Wood, TK},
title = {σ54 -Dependent Regulator DVU2956 Switches Desulfovibrio vulgaris from Biofilm Formation to Planktonic Growth and Regulates Hydrogen Sulfide Production.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.14679},
pmid = {31087603},
issn = {1462-2920},
abstract = {Microbiologically influenced corrosion causes $1011 in damage per year, and biofilms formed by sulfate-reducing bacteria (SRB) are the major culprit. However, little is known about the regulation of SRB biofilm formation. Using Desulfovibrio vulgaris as a model SRB organism, we compared the transcriptomes of biofilm and planktonic cells and identified that the gene for σ54 -dependent regulator DVU2956 is repressed in biofilms. Utilizing a novel promoter that is primarily transcribed in biofilms (Pdvu0304), we found production of DVU2956 inhibits biofilm formation by 70%. Corroborating this result, deleting dvu2956 increased biofilm formation, and this biofilm phenotype could be complemented. By producing proteins in biofilms from genes controlled by DVU2956 (dvu2960 and dvu2962), biofilm formation was inhibited almost completely. A second round of RNA-seq for the production of DVU2956 revealed DVU2956 influences electron transport via an Hmc complex (high-molecular weight cytochrome c encoded by dvu0531-dvu0536) and the Fe-only hydrogenase (encoded by dvu1769, hydA, and dvu1770, hydB) to control H2 S production. Corroborating these results, producing DVU2956 in biofilms decreased H2 S production by half, deleting dvu2956 increased H2 S production by 131 ± 5%, and producing DVU2956 in the dvu2956 strain reduced H2 S production. Therefore, DVU2956 maintains SRB in the planktonic state and reduces H2 S formation. This article is protected by copyright. All rights reserved.},
}
@article {pmid31087370,
year = {2019},
author = {Banerjee, A and Bardhan, R and Chowdhury, M and Joardar, SN and Isore, DP and Batabayl, K and Dey, S and Sar, TK and Bandyopadhyay, S and Dutta, TK and Samanta, I},
title = {Characterization of beta-lactamase and biofilm producing Enterobacteriaceae isolated from organized and backyard farm ducks.},
journal = {Letters in applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/lam.13170},
pmid = {31087370},
issn = {1472-765X},
abstract = {The present study was undertaken to detect the occurrence of beta-lactamase and biofilm producing Enterobacteriaceae in healthy ducks. A total 202 cloacal swabs were collected from ducks kept in organized (n=92) and backyard (n=110) farms in West Bengal (India). The ducks had no history of antibiotic intake. Among the 87 phenotypically beta-lactamase producing E. coli, 19 (17·43%), six (5·05%) and 15 (13·76%) isolates possessed blaTEM , blaSHV and blaCTX-M , respectively. Whereas, five (38·46%) Salmonella isolates were found to harbour blaCTX-M . In K. pneumoniae 10(33·33%), three (13·33%), four (13·33%) isolates possessed blaTEM , blaSHV and blaCTX-M , respectively. The sequences of selected PCR products were found 98% cognate with blaCTX-M-9, blaSHV-12 and blaTEM-1 . Beta-lactamase producing E. coli isolates belonged to 14 different serogroups such as O1, O2, O3, O5, O7, O8, O35, O83, O84, O88, O119, O128, O145 and O157. Moreover, 87 E. coli (79·82%), six Samonella (46·15%) and 13 K. pneumoniae (43·33%) isolates were detected as AmpC producers possessing blaAmpC . Majority of E. coli (46·79%), Salmonella (46·15%) and K. pneumoniae (70%) isolates were detected as biofilm producers and possessed the associated genes (csgA, sdiA, rcsA, rpoS). Significantly higher occurrence of beta-lactamase and biofilm producing Enterobacteriaceae isolates was detected in backyard ducks than organized farms. This article is protected by copyright. All rights reserved.},
}
@article {pmid31085909,
year = {2019},
author = {Dos Santos, DMS and Pires, JG and Silva, AB and Salomão, PMA and Buzalaf, MAR and Magalhães, AC},
title = {Protective Effect of 4% Titanium Tetrafluoride Varnish on Dentin Demineralization Using a Microcosm Biofilm Model.},
journal = {Caries research},
volume = {},
number = {},
pages = {1-8},
doi = {10.1159/000499317},
pmid = {31085909},
issn = {1421-976X},
abstract = {This study evaluated the effect of titanium tetrafluoride (TiF4) varnish on the development of dentin carious lesions. Bovine root dentin samples were treated for 6 h with: (A) 4% TiF4 varnish (2.45% F); (B) 5.42% sodium fluoride (NaF) varnish (2.45% F); (C) 2% chlorhexidine (CHX) gel - positive control; (D) placebo varnish; or (E) untreated - negative control (n = 4 × biological triplicate, n = 12). Treated dentin samples were exposed to human saliva mixed with McBain saliva (1:50) for the first 8 h in 24-well plates. Thereafter, the medium was removed, and McBain saliva containing 0.2% sucrose was applied for 16 h. From days 2 to 5, McBain saliva with sucrose was replaced daily (37°C, 5% CO2). The demineralization was measured using transverse microradiography, while the effect on biofilm was analyzed using viability, extracellular polysaccharide (EPS), and lactic acid production assays. The data were statistically analyzed (p < 0.05). All treatments (fluorides and CHX) significantly reduced the biofilm viability compared to placebo varnish and negative control. However, none of them was able to reduce the colony-forming unit counting for total microorganism, total streptococci, and Streptococcus mutans. NaF significantly reduced the number of Lactobacillus sp. compared to negative control. No effect was seen on lactic acid production neither on EPS synthesis, except that CHX significantly reduced the amount of insoluble EPS. Both fluorides were able to reduce dentin demineralization compared to placebo varnish and negative control; TiF4 had a better effect in reducing mineral loss and lesion depth than NaF. Therefore, TiF4 varnish has the best protective effect on dentin carious lesion formation using this model.},
}
@article {pmid31085695,
year = {2019},
author = {Matysik, A and Kline, KA},
title = {Streptococcus pyogenes capsule promotes microcolony-independent biofilm formation.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00052-19},
pmid = {31085695},
issn = {1098-5530},
abstract = {Biofilms play an important role in the pathogenesis of Group A Streptococcus (GAS), a gram-positive pathogen responsible for a wide range infections and significant public health impact. Although most GAS serotypes are able to form biofilms, there is large heterogeneity between individual strains in biofilm formation, as measured by standard crystal violet assays. It is generally accepted that biofilm formation includes initial adhesion of bacterial cells to a surface, followed by microcolony formation, biofilm maturation, and extensive production of extracellular matrix that links together proliferating cells and provides a scaffold for the three-dimensional biofilm structure. However, our studies show that for GAS strain JS95, microcolony formation is not an essential step in static biofilm formation, and instead, biofilm can be effectively formed from slow-growing or non-replicating late exponential or early stationary planktonic cells, via sedimentation and fixation of GAS chains into biofilms. In addition, we show that the GAS capsule specifically contributes to the alternative, sedimentation-initiated biofilms. Microcolony-independent, sedimentation biofilms are similar in morphology and 3-D structure to biofilms initiated by actively dividing planktonic bacteria. We conclude that GAS can form biofilms by an alternate, non-canonical mechanism that does not require transition from microcolony formation to biofilm maturation, and which may be obscured by biofilm phenotypes that arise via the classical biofilm maturation processes.IMPORTANCEThe static biofilm assay is a common tool for easy biomass quantification of biofilm forming bacteria. However, S. pyogenes biofilm formation as measured by the static assay is strain dependent and yields heterogeneous results for different strains of the same serotype. In this study, we show that two independent mechanisms, for which the protective capsule contributes opposing functions, may contribute to static biofilm formation. We propose that separation of these mechanisms for biofilm formation might uncover previously unappreciated biofilm phenotypes that may otherwise be masked in the classic static assay.},
}
@article {pmid31085409,
year = {2019},
author = {Wan, D and Li, Q and Chen, J and Niu, Z and Liu, Y and Li, H and Xiao, S},
title = {Simultaneous bio-electrochemical reduction of perchlorate and electro-disinfection in a novel Moving-Bed Biofilm Reactor (MBBR) based on proton-exchange membrane electrolysis.},
journal = {The Science of the total environment},
volume = {679},
number = {},
pages = {288-297},
doi = {10.1016/j.scitotenv.2019.04.441},
pmid = {31085409},
issn = {1879-1026},
abstract = {A novel Moving-Bed Biofilm Reactor (MBBR), based on proton-exchange membrane electrolysis, was developed and tested for perchlorate transformation. The bacteria growing on the carrier in the cathode chamber could use in situ-generated hydrogen to reduce perchlorate to chloride via electrolysis; the resulting chloride ions and chloride ions in raw water were then oxidized into chlorine by anode reaction to disinfect the final effluent and improve water quality. For a ClO4- concentration of 10.00 ± 0.08 mg/L in the influent, at hydraulic retention times (HRTs) of 4.0, 2.0, and 1.5 h, the optimal applied currents (OACs) were 130, 240, and 270 mA, with a corresponding removal efficiencies of 99.90 ± 0.21, 96.70 ± 0.36, and 78.50 ± 0.24%, respectively. Active chlorine concentration was in the range of 0.063-0.096 mg/L, contributing to simultaneous electro-disinfection. Along the water flow direction, OH- generated by the cathode could be neutralized in the anode chamber; thus, the final effluent pH was kept a balance with the influent pH. Proteobacteria, Bacteroidetes, and Firmicutes were the dominant bacteria in the MBBR. The maximum value of current efficiency (13.32 ± 0.69%) was obtained at 100 mA and an HRT of 4.0 h, which was in accordance with the abundance of Thauera.},
}
@article {pmid31085405,
year = {2019},
author = {Wall, G and Montelongo-Jauregui, D and Vidal Bonifacio, B and Lopez-Ribot, JL and Uppuluri, P},
title = {Candida albicans biofilm growth and dispersal: contributions to pathogenesis.},
journal = {Current opinion in microbiology},
volume = {52},
number = {},
pages = {1-6},
doi = {10.1016/j.mib.2019.04.001},
pmid = {31085405},
issn = {1879-0364},
abstract = {The fungal species Candida albicans is most frequently associated with biofilm formation in immune-compromised and medically compromised patients, and it is now firmly established that biofilm formation represents a major virulence factor during candidiasis. A growing body of evidence has demonstrated that C. albicans biofilm development is a highly regulated and coordinated process, where adhesive interactions, morphogenetic conversions, and consortial behavior play significant roles. Cells within the biofilms are protected from environmental stresses including host immune defenses and antifungal treatment, which carries important clinical consequences for the treatment of biofilm-associated infections. Dispersal of cells from biofilms represents one of the hallmarks of the biofilm life-style, and in the case of C. albicans dispersed cells are responsible for candidemia and dissemination leading to the establishment of invasive disease.},
}
@article {pmid31085344,
year = {2019},
author = {Girish, VM and Liang, H and Aguilan, JT and Nosanchuk, JD and Friedman, JM and Nacharaju, P},
title = {Anti-biofilm activity of garlic extract loaded nanoparticles.},
journal = {Nanomedicine : nanotechnology, biology, and medicine},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.nano.2019.04.012},
pmid = {31085344},
issn = {1549-9642},
abstract = {The emergence and widespread distribution of multi-drug resistant bacteria is considered as a major public health concern. The inabilities to curb severe infections due to antibiotic resistance have increased healthcare costs as well as patient morbidity and mortality. Bacterial biofilms formed by drug-resistant bacteria add additional challenges to treatment. This study describes a sol-gel based nanoparticle system loaded with garlic extract (GE-np) that exhibits: i) slow and sustained release of garlic components; ii) stabilization of the active components; and iii) significant enhancement of antimicrobial and antibiofilm activity relative to the free garlic extract. Also, GE-np were efficient in penetrating and disrupting the well-established methicillin-resistant Staphylococcus aureus (MRSA) biofilms. Overall, the study suggests that GE-np might be a promising candidate for the treatment of chronic infections due to biofilm forming drug-resistant bacteria.},
}
@article {pmid31083437,
year = {2019},
author = {Nagel, C and Machulla, A and Zahn, S and Soppa, J},
title = {Several One-Domain Zinc Finger µ-Proteins of Haloferax Volcanii Are Important for Stress Adaptation, Biofilm Formation, and Swarming.},
journal = {Genes},
volume = {10},
number = {5},
pages = {},
doi = {10.3390/genes10050361},
pmid = {31083437},
issn = {2073-4425},
support = {SO 264/26-1//Deutsche Forschungsgemeinschaft/ ; },
abstract = {Zinc finger domains are highly structured and can mediate interactions to DNA, RNA, proteins, lipids, and small molecules. Accordingly, zinc finger proteins are very versatile and involved in many biological functions. Eukaryotes contain a wealth of zinc finger proteins, but zinc finger proteins have also been found in archaea and bacteria. Large zinc finger proteins have been well studied, however, in stark contrast, single domain zinc finger µ-proteins of less than 70 amino acids have not been studied at all, with one single exception. Therefore, 16 zinc finger µ-proteins of the haloarchaeon Haloferax volcanii were chosen and in frame deletion mutants of the cognate genes were generated. The phenotypes of mutants and wild-type were compared under eight different conditions, which were chosen to represent various pathways and involve many genes. None of the mutants differed from the wild-type under optimal or near-optimal conditions. However, 12 of the 16 mutants exhibited a phenotypic difference under at least one of the four following conditions: Growth in synthetic medium with glycerol, growth in the presence of bile acids, biofilm formation, and swarming. In total, 16 loss of function and 11 gain of function phenotypes were observed. Five mutants indicated counter-regulation of a sessile versus a motile life style in H. volcanii. In conclusion, the generation and analysis of a set of deletion mutants demonstrated the high importance of zinc finger µ-proteins for various biological functions, and it will be the basis for future mechanistic insight.},
}
@article {pmid31083366,
year = {2019},
author = {Foster, LL and Yusa, SI and Kuroda, K},
title = {Solution-Mediated Modulation of Pseudomonas aeruginosa Biofilm Formation by a Cationic Synthetic Polymer.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {2},
pages = {},
doi = {10.3390/antibiotics8020061},
pmid = {31083366},
issn = {2079-6382},
support = {U01DE023771//National Institutes of Health/ ; DGE-1315231//National Science Graduate Research Fellowship/ ; },
abstract = {Bacterial biofilms and their associated infections are a continuing problem in the healthcare community. Previous approaches utilizing anti-biofilm coatings suffer from short lifetimes, and their applications are limited to surfaces. In this research, we explored a new approach to biofilm prevention based on the hypothesis that changing planktonic bacteria behavior to result in sub-optimal biofilm formation. The behavior of planktonic Pseudomonas aeruginosa exposed to a cationic polymer was characterized for changes in growth behavior and aggregation behavior, and linked to resulting P. aeruginosa biofilm formation, biomass, viability, and metabolic activity. The incubation of P. aeruginosa planktonic bacteria with a cationic polymer resulted in the aggregation of planktonic bacteria, and a reduction in biofilm development. We propose that cationic polymers may sequester planktonic bacteria away from surfaces, thereby preventing their attachment and suppressing biofilm formation.},
}
@article {pmid31082673,
year = {2019},
author = {Guo, X and Li, B and Zhao, R and Zhang, J and Lin, L and Zhang, G and Li, RH and Liu, J and Li, P and Li, Y and Li, XY},
title = {Performance and bacterial community of moving bed biofilm reactors with various biocarriers treating primary wastewater effluent with a low organic strength and low C/N ratio.},
journal = {Bioresource technology},
volume = {287},
number = {},
pages = {121424},
doi = {10.1016/j.biortech.2019.121424},
pmid = {31082673},
issn = {1873-2976},
abstract = {A laboratory-scale sequencing batch reactor (SBR) and two moving bed biofilm reactors (MBBRs) with different types of biocarriers were operated to treat the effluent of chemically enhanced primary sedimentation (CEPS). Due to the low organic strength and low carbon/nitrogen ratio of the CEPS effluent, COD and NH4+-N were effectively removed by the MBBRs but not by the SBR. Of the two MBBRs, MBBR2 filled with LEVAPOR biocarrier cubes performed even better than MBBR1 filled with K3 polystyrene biocarriers. The continuous decline of the sludge concentration in the SBR and the high and stable biomass content in MBBR2 contributed to their performances. High-throughput sequencing analysis showed that the reactors had selective effects on the bacterial community structure. Principal coordinate analysis indicated the different dynamic successions in the three reactors. Network analysis showed different community composition and diversity that were highly suggestive of different bacterial interactions among the three bioreactors.},
}
@article {pmid31081821,
year = {2019},
author = {Panariello, BHD and Garcia, BA and Duarte, S},
title = {Daily Phototherapy with Red Light to Regulate Candida albicans Biofilm Growth.},
journal = {Journal of visualized experiments : JoVE},
volume = {},
number = {146},
pages = {},
doi = {10.3791/59326},
pmid = {31081821},
issn = {1940-087X},
abstract = {Here, we present a protocol to assess the outcomes of per diem red light treatment on the growth of Candida albicans biofilm. To increase the planktonic growth of C. albicans SN425, the inoculums grew on Yeast Nitrogen Base media. For biofilm formation, RPMI 1640 media, which have high concentrations of amino acids, were applied to help biofilm growth. Biofilms of 48 h were treated twice a day for a period of 1 min with a non-coherent light device (red light; wavelength = 635 nm; energy density = 87.6 J·cm-2). As a positive control (PC), 0.12% chlorhexidine (CHX) was applied, and as a negative control (NC), 0.89% NaCl was applied to the biofilms. Colony forming units (CFU), dry-weight, soluble and insoluble exopolysaccharides were quantified after treatments. Briefly, the protocol presented here is simple, reproducible and provides answers regarding viability, dry-weight and extracellular polysaccharide amounts after red light treatment.},
}
@article {pmid31080568,
year = {2019},
author = {Mai, HN and Hong, SH and Kim, SH and Lee, DH},
title = {Effects of different finishing/polishing protocols and systems for monolithic zirconia on surface topography, phase transformation, and biofilm formation.},
journal = {The journal of advanced prosthodontics},
volume = {11},
number = {2},
pages = {81-87},
doi = {10.4047/jap.2019.11.2.81},
pmid = {31080568},
issn = {2005-7806},
abstract = {PURPOSE: The purpose of this study was to evaluate the effects of various protocols and systems for finishing and polishing monolithic zirconia on surface topography, phase transformation, and bacterial adhesion.<br><br>MATERIALS AND METHODS: Three hundred monolithic zirconia specimens were fabricated and then treated with three finishing and polishing systems (Jota [JO], Meisinger [ME], and Edenta [ED]) using four surface treatment protocols: coarse finishing alone (C); coarse finishing and medium polishing (CM); coarse finishing and fine polishing (CF); and coarse finishing, medium polishing, and fine polishing (CMF). Surface roughness, crystal phase transformation, and bacterial adhesion were evaluated using atomic force microscopy, X-ray diffraction, and streptococcal biofilm formation assay, respectively. One-way and two-way analysis of variance with Tukey post hoc tests were used to analyze the results (α=.05).<br><br>RESULTS: In this study, the surface treatment protocols and systems had significant effects on the resulting roughness. The CMF protocol produced the lowest roughness values, followed by CM and CF. Use of the JO system produced the lowest roughness values and the smallest biofilm mass, while the ME system produced the smallest partial transformation ratio. The ED group exhibited the highest roughness values, biofilm mass, and partial transformation ratio.<br><br>CONCLUSION: Stepwise surface treatment of monolithic zirconia, combined with careful polishing system selection, is essential to obtaining optimal microstructural and biological surface results.},
}
@article {pmid31079197,
year = {2019},
author = {Pillot, G and Davidson, S and Auria, R and Combet-Blanc, Y and Godfroy, A and Liebgott, PP},
title = {Production of Current by Syntrophy Between Exoelectrogenic and Fermentative Hyperthermophilic Microorganisms in Heterotrophic Biofilm from a Deep-Sea Hydrothermal Chimney.},
journal = {Microbial ecology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00248-019-01381-z},
pmid = {31079197},
issn = {1432-184X},
support = {PEPS-ExoMod 2016//Institut National des Sciences de l'Univers, Centre National de la Recherche Scientifique/ ; 1166-39417//European Regional Development Fund/ ; },
abstract = {To study the role of exoelectrogens within the trophic network of deep-sea hydrothermal vents, we performed successive subcultures of a hyperthermophilic community from a hydrothermal chimney sample on a mix of electron donors in a microbial fuel cell system. Electrode (the electron acceptor) was swapped every week to enable fresh development from spent media as inoculum. The MFC at 80 °C yielded maximum current production increasing from 159 to 247 mA m-2 over the subcultures. The experiments demonstrated direct production of electric current from acetate, pyruvate, and H2 and indirect production from yeast extract and peptone through the production of H2 and acetate from fermentation. The microorganisms found in on-electrode communities were mainly affiliated to exoelectrogenic Archaeoglobales and Thermococcales species, whereas in liquid media, the communities were mainly affiliated to fermentative Bacillales and Thermococcales species. The work shows interactions between fermentative microorganisms degrading complex organic matter into fermentation products that are then used by exoelectrogenic microorganisms oxidizing these reduced compounds while respiring on a conductive support. The results confirmed that with carbon cycling, the syntrophic relations between fermentative microorganisms and exoelectrogens could enable some microbes to survive as biofilm in extremely unstable conditions. Graphical Abstract Schematic representation of cross-feeding between fermentative and exoelectrogenic microbes on the surface of the conductive support. B, Bacillus/Geobacillus spp.; Tc, Thermococcales; Gg, Geoglobus spp.; Py, pyruvate; Ac, acetate.},
}
@article {pmid31079168,
year = {2019},
author = {Edel, M and Horn, H and Gescher, J},
title = {Biofilm systems as tools in biotechnological production.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-019-09869-x},
pmid = {31079168},
issn = {1432-0614},
support = {DFG HO 1910/16-1//Deutsche Forschungsgemeinschaft/ ; },
abstract = {The literature provides more and more examples of research projects that develop novel production processes based on microorganisms organized in the form of biofilms. Biofilms are aggregates of microorganisms that are attached to interfaces. These viscoelastic aggregates of cells are held together and are embedded in a matrix consisting of multiple carbohydrate polymers as well as proteins. Biofilms are characterized by a very high cell density and by a natural retentostat behavior. Both factors can contribute to high productivities and a facilitated separation of the desired end-product from the catalytic biomass. Within the biofilm matrix, stable gradients of substrates and products form, which can lead to a differentiation and adaptation of the microorganisms' physiology to the specific process conditions. Moreover, growth in a biofilm state is often accompanied by a higher resistance and resilience towards toxic or growth inhibiting substances and factors. In this short review, we summarize how biofilms can be studied and what most promising niches for their application can be. Moreover, we highlight future research directions that will accelerate the advent of productive biofilms in biology-based production processes.},
}
@article {pmid31078982,
year = {2019},
author = {Su, JF and Zhang, YM and Liang, DH and Wang, JX and Wang, Z and Li, M},
title = {Performance and microbial community of an immobilized biofilm reactor (IBR) for Mn(II)-based autotrophic and mixotrophic denitrification.},
journal = {Bioresource technology},
volume = {286},
number = {},
pages = {121407},
doi = {10.1016/j.biortech.2019.121407},
pmid = {31078982},
issn = {1873-2976},
abstract = {An immobilized biofilm reactor (IBR) was established to treat nitrate using different electron donors. A novel material, Fe3O4@Cu/PVA, was synthesized as an adsorbent and bacterial immobilized carrier in the reactor. The optimum condition of nitrate removal were pH 7.0, hydraulic retention time (HRT) of 10 h under autotrophic and mixotrophic conditions. Strain H-117 in the mixotrophic reactor had better adaptability to changes in the initial pH. The metabolism in the mixotrophic reactor was more vigorous than that in autotrophic reactor. The microbial communities and structures were evaluated to determine the nitrate removal mechanisms in this system. Microbial analyses demonstrated that different electron donor could influence the bacterial abundance and species in the IBR system. Proteobacteria was the most dominant phylum in all IBRs and accounted for more than 50% of the total phyla. Pseudomonas and Rhizobium were the dominant contributor to the effective removal of nitrate in the IBRs.},
}
@article {pmid31078886,
year = {2019},
author = {Ahmed, W and Tian, X and Delatolla, R},
title = {Nitrifying moving bed biofilm reactor: Performance at low temperatures and response to cold-shock.},
journal = {Chemosphere},
volume = {229},
number = {},
pages = {295-302},
doi = {10.1016/j.chemosphere.2019.04.176},
pmid = {31078886},
issn = {1879-1298},
abstract = {In contrast with suspended growth systems, attached growth technologies such as the moving bed biofilm reactors (MBBR) have recently demonstrated significant nitrification rates at temperatures as low as 1 °C. The purpose of this study was to investigate the performance of the nitrifying MBBR system at elevated municipal concentrations with exposures to low temperatures and cold-shock conditions down to 1 °C using an enhanced temperature-controlled room. A removal rate of 98.44 ± 4.69 gN·m-3·d-1 was identified as the intrinsic rate of nitrifying MBBR systems at 1 °C and was proposed as the conservative rate for low temperature design. A temperature threshold at which attached growth nitrification displayed a significant decrease in kinetics was identified between 2 °C and 4 °C. Arrhenius correction coefficients of 1.086 and 1.09 previously applied for low temperature nitrifying MBBR systems resulted in conservative modeled removal rates on average 21% lower than the measured rates. Thus, an Arrhenius correction coefficient of 1.049 is proposed between the temperatures of 10 °C and 4 °C and another correction coefficient of 1.149 to model rates at 1 °C. For the transition from 4 °C to 1 °C, the adjustment of a previously reported Theta model is proposed in this study to account for exposure time at low temperatures; with the modified model showing strong correlation with measured rates (R2 = 0.88). Finally, a comparison of nitrification kinetics between MBBR systems acclimatized to 1 °C and systems that are cold-shocked to 1 °C demonstrated that shocked removal rates are 21% lower.},
}
@article {pmid31077449,
year = {2019},
author = {Bermejo, P and Sánchez, MC and Llama-Palacios, A and Figuero, E and Herrera, D and Sanz, M},
title = {Biofilm formation on dental implants with different surface micro-topography: an in vitro study.},
journal = {Clinical oral implants research},
volume = {},
number = {},
pages = {},
doi = {10.1111/clr.13455},
pmid = {31077449},
issn = {1600-0501},
abstract = {OBJECTIVES: To compare biofilm formation on whole dental titanium implants with different surface micro-topography METHODS: A multispecies in vitro biofilm model consisting on initial (Streptococcus oralis and Actinomyces naeslundii), early (Veillonella parvula), secondary (Fusobacterium nucleatum) and late colonizers (Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans) was grown for 96 h on sterile titanium dental implants with either minimal (Sa : 0.5-1.0 mm) or moderate-roughness titanium surfaces (Sa : 1.1-2.0 mm). The resulting biofilms were studied with Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscope. Concentrations (colony forming units per mL [CFU/mL]) of each bacterium were measured by quantitative Polymerase Chain Reaction (qPCR) and compared by Student T-tests.<br><br>RESULTS: A biofilm, located mainly at the peak and lateral areas of the implant threads, was observed on both implant surfaces, with a greater biomass and a greater live/dead ratio in moderate-, compared to minimal-roughness surface implants. Statistically significant higher values of total bacteria (mean difference=2.61x107 CFU/mL; 95% confidence interval - CI [1.91x106 ; 5.02x107 ]; p=0.036), F. nucleatum (mean difference=4.43x106 CFU/mL; 95% CI [1.06x106 ; 7.80x106 ]; p=0.013) and A. actinomycetemcomitans (mean difference=2.55x107 CFU/mL; 95% CI [1.07x107 ; 4.04x107 ]; p=0.002) were found in the moderate-, compared to minimal-roughness surface dental implants.<br><br>CONCLUSIONS: Implants with moderate-roughness surfaces accumulated more bacterial biomass and significant higher number of pathogenic bacteria (F. nucleatum and A. actinomycetemcomitans), when compared to implants with minimal-roughness surfaces, within a similar biofilm structure. This article is protected by copyright. All rights reserved.},
}
@article {pmid31077423,
year = {2019},
author = {Alves, AR and Sequeira, AM and Cunha, Â},
title = {Increase of bacterial biosurfactant production by co-cultivation with biofilm-forming bacteria.},
journal = {Letters in applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/lam.13169},
pmid = {31077423},
issn = {1472-765X},
abstract = {Considering that bacterial biosurfactants (BSFs) are released as secondary metabolites involved in biotic relations within mixed bacterial assemblages, the hypothesis that the co-cultivation of BSF producing bacteria with biofilm-forming strains would enhance BSF synthesis was tested. Environmental BSF producing strains of Bacillus licheniformis and Pseudomonas sp. were cultivated with reference biofilm-forming strains (Pseudomonas aeruginosa and Listeria innocua). BSF production and quorum quenching effects were tested in solid media. Tensioactive and anionic BSFs were also quantified in cell-free extracts (CFEs). BSF production increased in co-cultures with inducer strains although this was not demonstrated by all screening methods. Increased concentrations of anionic BSF were detected in CFEs of co-cultures in which Pseudomonas aeruginosa was included as inducer, which is in accordance with the observation of larger halos in cetyl trimethylammonium bromide-methylene blue agar. The results demonstrate that co-cultivation positively affects the efficiency of BSF production and that higher production yields may be attained by selecting convenient inducer partners in designed consortia. This article is protected by copyright. All rights reserved.},
}
@article {pmid31077283,
year = {2019},
author = {Zeng, Z and Zang, W and Wang, W and Wang, P and Tang, K and Wang, X},
title = {Biofilm formation in Pseudoalteromonas lipolytica is related to IS5-like insertions in the capsular polysaccharide operon.},
journal = {FEMS microbiology ecology},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsec/fiz065},
pmid = {31077283},
issn = {1574-6941},
abstract = {Bacterial capsular polysaccharides (CPSs) participate in environmental adaptation in diverse bacteria species. However, the role and regulation of CPS production in marine bacteria have remained largely unexplored. We previously reported that both wrinkled and translucent Pseudoalteromonas lipolytica variants with altered polysaccharide production were generated in pellicle biofilm-associated cells. In this study, we observed that translucent variants were generated at a rate of ∼20% in colony biofilms of P. lipolytica cultured on HSLB agar plates for 12 days. The DNA sequencing results revealed that nearly 90% of these variants had an IS5-like element inserted within the coding or promoter regions of nine genes in the cps operon. In contrast, IS5 insertion into the cps operon was not detected in planktonic cells. Furthermore, we demonstrated that the IS5 insertion event inactivated CPS production, which leads to a translucent colony morphology. The CPS-deficient variants showed an increased ability to form attached biofilms but exhibited reduced resistance to sublethal concentrations of antibiotics. Moreover, deleting the DNA repair gene recA significantly decreased the frequency of occurrence of CPS-deficient variants during biofilm formation. Thus, IS insertion into the cps operon is an important mechanism for the production of genetic variants during biofilm formation of marine bacteria.},
}
@article {pmid31076293,
year = {2019},
author = {Peng, C and Gao, Y and Fan, X and Peng, P and Huang, H and Zhang, X and Ren, H},
title = {Enhanced biofilm formation and denitrification in biofilters for advanced nitrogen removal by rhamnolipid addition.},
journal = {Bioresource technology},
volume = {},
number = {},
pages = {121387},
doi = {10.1016/j.biortech.2019.121387},
pmid = {31076293},
issn = {1873-2976},
abstract = {Denitrification biofilters (DNBFs) are widely used in advanced nitrogen removal of wastewater with low C/N and effective biofilm formation is critical to their long-term operation. Hereby the influence of rhamnolipid addition in DNBFs was investigated for the first time. Gradient concentrations (0, 20, 40, 80, 120 mg/L) of rhamnolipid were applied to investigate nitrogen removal, biofilm properties and microbial community of lab-scale DNBFs. A significant increase of nitrogen removal was observed in rhamnolipid-treated DNBFs (p < 0.05). Total solid (TS), extracellular polymeric substances (EPS) and adhesion force of biofilms in DNBF with 120 mg/L rhamnolipid reached the maximum, which were 2.17, 2.15 and 3.36 times of those in the control, respectively. Moreover, rhamnolipid exhibited an improvement in abundance of Simplicispira and Gemmatimonas which were responsible for enhanced biofilm formation and denitrification. The results suggested that rhamnolipid addition can be a novel strategy to improve the start-up and denitrification performance of DNBFs.},
}
@article {pmid31075206,
year = {2019},
author = {Gou, Y and Liu, W and Wang, J and Tan, L and Hong, B and Guo, L and Liu, H and Pan, Y and Zhao, Y},
title = {CRISPR-Cas9 knockout of qseB induced asynchrony between motility and biofilm formation in Escherichia coli.},
journal = {Canadian journal of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1139/cjm-2019-0100},
pmid = {31075206},
issn = {1480-3275},
abstract = {Generally, there is a tight regulation between cell motility and biofilm formation. The two-component system (TCS) of QseBC serves as a bridge for bacterial signal transmission, in which QseB acts as a response regulator to regulate bacterial motility, biofilm and virulence. The interaction mechanisms between QseBC and their functions have been generally studied, but the regulation of QseB on bacterial motility and biofilm formation is unknown. In this study, CRISPR-Cas9 system was used to construct the strain of Escherichia coli MG1655ΔqseB (ΔqseB strain), and the effects of gene qseB on the changes of motility and biofilm formation of Wild-type (WT) were determined. The motility assay results showed that the ΔqseB strain had higher (p<0.05) mobility than that of the WT strain. Nevertheless, there was no difference in the biofilm formation between ΔqseB and WT. The real-time quantitative PCR (qRT-PCR) illustrated that deletion of qseB in the WT strain down-regulated the expression of the type I pili gene fimA. Therefore, we might conclude that the ΔqseB induced the down-regulation of fimA, which led to asynchrony between motility and biofilm formation in E. coli, which provide a new insight into the functional importance of QseB in regulating the cell motility and biofilm.},
}
@article {pmid31071421,
year = {2019},
author = {Mehta, M and Allen-Gipson, D and Mohapatra, S and Kindy, M and Limayem, A},
title = {Study on the therapeutic index and synergistic effect of Chitosan-Zinc Oxide nanomicellar composites for drug-resistant bacterial biofilm inhibition.},
journal = {International journal of pharmaceutics},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijpharm.2019.05.003},
pmid = {31071421},
issn = {1873-3476},
abstract = {The synergistic effectiveness of chitosan with zinc oxide nanomicelles (CZNPs) on broad spectrum of multidrug resistance (MDR) was previously evidenced in our labs, requiring elucidation of the therapeutic index (TI) for safe in vivo use. This in vitro assessment estimated the effective dose (ED50) of micellar CZNPs for eradication of the MDR Enterococcus faecium 1449 model and the corresponding cytotoxic dose (LD50) against rat small intestinal epithelial cells as functions of TI. In order to visually determine the mechanistic effects of micellar CZNPs on bacterial biofilm size reduction, LIVE/DEAD viability assay was used in conjunction with advanced fluorescence imaging and 3D confocal microscopy. Biofilm quantification was performed through the measure of the fluorescence intensity, using the Biotek Synergy Neo2 for calculating the ED50. To generate the LD50, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assay was implemented. Quantification results revealed, at the same concentration (200 µg/mL), micellar CZNPs had average biofilm reduction of approximately 50.22% at 24 hours (ED50 = 199.13 µg/mL, LD50 = 240.20 µg/mL, TI = 1.2062), compared to chitosan (15.66%) and ZnO (13.94%) alone. Conclusively, the ED50 of micellar CZNPs on MDR bacterial biofilms (199.13 µg/mL) as a function of TI reveals a promising nanotherapeutic agent in comparison to either Chitosan or ZnO alone.},
}
@article {pmid31070474,
year = {2019},
author = {Guo, D and Yang, Z and Zheng, X and Kang, S and Yang, Z and Xu, Y and Shi, C and Tian, H and Xia, X},
title = {Thymoquinone Inhibits Biofilm Formation and Attachment-Invasion in Host Cells of Vibrio parahaemolyticus.},
journal = {Foodborne pathogens and disease},
volume = {},
number = {},
pages = {},
doi = {10.1089/fpd.2018.2591},
pmid = {31070474},
issn = {1556-7125},
abstract = {Vibrio parahaemolyticus is a halophilic Gram-negative foodborne pathogen that is widely distributed in marine environments. It can cause acute gastroenteritis and other diseases. This study aimed to investigate the antivirulence activity of thymoquinone (TQ) on V. parahaemolyticus. TQ was shown to effectively inhibit V. parahaemolyticus. Subminimum inhibitory concentrations of TQ inhibited swimming and swarming motility, quorum sensing, biofilm formation, the ability of V. parahaemolyticus to adhere and invade the host cells, and the expression of virulence-associated genes of V. parahaemolyticus. These findings suggest that TQ can effectively inhibit the growth of V. parahaemolyticus and significantly reduce its pathogenicity. Considering its safety and various biological activities, TQ has the potential to be developed as a natural antibacterial substance to reduce the diseases associated with V. parahaemolyticus.},
}
@article {pmid31067024,
year = {2019},
author = {Zhou, R and Zhou, R and Wang, P and Luan, B and Zhang, X and Fang, Z and Xian, Y and Lu, X and Ostrikov, KK and Bazaka, K},
title = {Microplasma Bubbles: Reactive Vehicles for Biofilm Dispersal.},
journal = {ACS applied materials &amp; interfaces},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsami.9b03961},
pmid = {31067024},
issn = {1944-8252},
abstract = {Interactions between effects generated by cold atmospheric-pressure plasmas (CAPPs) and water have been widely investigated water purification, chemical and nanomaterial synthesis, and more recently, medicine and biotechnology. Reactive oxygen and nitrogen species (RONS) play critical roles in transferring the reactivity from gas plasmas to solutions to induce specific biochemical responses in living targets, e.g. pathogen inactivation and biofilm removal. While this approach works well in a single-organism system at lab scale, integration of plasma-enabled biofilm removal into complex real-life systems, e.g. large aquaculture tanks, is far from trivial. This is because it is difficult to deliver sufficient concentrations of the right kind of species to biofilm-covered surfaces while carefully maintaining a suitable physiochemical environment that is healthy for its inhabitants, e.g. fish. In this work, we show that underwater microplasma bubbles (generated by a microplasma-bubble reactor that forms a dielectric barrier discharge (DBD) at the gas-liquid interface with the aplied voltage of 4.0 kV) act as transport vehicles to efficiently deliver reactive plasma species to target biofilm sites on artificial and living surfaces while keeping healthy water conditions in a multi-species system. Thus-generated air microplasma bubbles and plasma activated water (PAW) both can effectively reduce existing pathogenic biofilm load, by ~83% and 60% respectively after 15 min-discharge at 40 W, and prevent any new biofilm from forming. Generation of underwater microplasma bubbles in a custom-made fish tank for less than a minute per day (20 seconds per-time, twice daily) can introduce sufficient quantities of RONS into PAW to reduce biofilm infected area by ~80-90% and imrpove the health status of Cichlasoma synspilum × Cichlasoma citrinellum blood parrot cichlid fish. Species generated include hydrogen peroxide, ozone, nitrite, nitrate and nitric oxide. Using mimicked chemical solutions, we show that plasma-induced nitric oxide acts as a critical bioactive species that triggers the release of cells from biofilm and their inactivation.},
}
@article {pmid31066733,
year = {2019},
author = {Zhang, C and Du, C and Liao, JY and Gu, Y and Gong, Y and Pei, J and Gu, H and Yin, D and Gao, L and Pan, Y},
title = {Synthesis of magnetite hybrid nanocomplexes to eliminate bacteria and enhance biofilm disruption.},
journal = {Biomaterials science},
volume = {},
number = {},
pages = {},
doi = {10.1039/c9bm00057g},
pmid = {31066733},
issn = {2047-4849},
abstract = {Bacteria can increase drug resistance by forming bacterial biofilms. Once the biofilm is formed, it becomes difficult to remove or kill the related bacteria completely by antibiotics and other antibacterial agents because these antibacterial agents cannot easily break through the biofilm matrix barrier and reach the internal bacteria. Therefore, we synthesized magnetite hybrid nanocomplexes that can penetrate and disrupt bacterial biofilms. The obtained nanocomposites are composed of multinucleated iron oxides and Ag seeds. The outer iron oxides can help the internal Ag nanoparticles penetrate the bacterial biofilms, hence killing the internal bacteria and disrupting the biofilms. We took advantage of E. coli and P. aeruginosa bacteria to test the antibacterial properties of the magnetite hybrid nanocomplexes. When planktonic E. coli and P. aeruginosa bacteria were incubated with 100 μg mL-1 magnetite hybrid nanocomplexes for 30 min, almost all the bacteria were killed. When the obtained biofilms of E. coli and P. aeruginosa were treated with magnetite hybrid nanocomplexes (10 μg mL-1 and 100 μg mL-1), the survival of E. coli and P. aeruginosa biofilms with a magnetic field showed a big decrease compared with that without a magnetic field. Therefore, the as-synthesized nanocomposites have promising potential as antimicrobial agents for killing bacteria and disrupting biofilms in the presence of a magnetic field, and thus should be further studied for a wide range of antibacterial applications.},
}
@article {pmid31064142,
year = {2019},
author = {Wei, C and Ding, T and Chang, C and Yu, C and Li, X and Liu, Q},
title = {Global Regulator PhoP is Necessary for Motility, Biofilm Formation, Exoenzyme Production and Virulence of Xanthomonas citri Subsp. citri on Citrus Plants.},
journal = {Genes},
volume = {10},
number = {5},
pages = {},
doi = {10.3390/genes10050340},
pmid = {31064142},
issn = {2073-4425},
support = {31371903//National Natural Science Foundation of China/ ; 31371903//China/ ; },
abstract = {Citrus canker caused by Xanthomonas citri subsp. citri is one of the most important bacterial diseases of citrus, impacting both plant growth and fruit quality. Identifying and elucidating the roles of genes associated with pathogenesis has aided our understanding of the molecular basis of citrus-bacteria interactions. However, the complex virulence mechanisms of X. citri subsp. citri are still not well understood. In this study, we characterized the role of PhoP in X. citri subsp. citri using a phoP deletion mutant, ΔphoP. Compared with wild-type strain XHG3, ΔphoP showed reduced motility, biofilm formation, as well as decreased production of cellulase, amylase, and polygalacturonase. In addition, the virulence of ΔphoP on citrus leaves was significantly decreased. To further understand the virulence mechanisms of X. citri subsp. citri, high-throughput RNA sequencing technology (RNA-Seq) was used to compare the transcriptomes of the wild-type and mutant strains. Analysis revealed 1017 differentially-expressed genes (DEGs), of which 614 were up-regulated and 403 were down-regulated in ΔphoP. Gene ontology functional enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses suggested that the DEGs were enriched in flagellar assembly, two-component systems, histidine metabolism, bacterial chemotaxis, ABC transporters, and bacterial secretion systems. Our results showed that PhoP activates the expression of a large set of virulence genes, including 22 type III secretion system genes and 15 type III secretion system effector genes, as well as several genes involved in chemotaxis, and flagellar and histidine biosynthesis. Two-step reverse-transcription polymerase chain reaction analysis targeting 17 genes was used to validate the RNA-seq data, and confirmed that the expression of all 17 genes, except for that of virB1, decreased significantly. Our results suggest that PhoP interacts with a global signaling network to co-ordinate the expression of multiple virulence factors involved in modification and adaption to the host environment during infection.},
}
@article {pmid31063858,
year = {2019},
author = {Misba, L and Abdulrahman, H and Khan, AU},
title = {Photodynamic efficacy of toluidine blue O against mono species and dual species bacterial biofilm.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.05.001},
pmid = {31063858},
issn = {1873-1597},
abstract = {AIM: The purpose of this study was to investigate how Enterococcus faecalis and Streptococcus mutans behave in mono and dual species biofilm after photodynamic treatment.<br><br>BACKGROUND: Antimicrobial photodynamic therapy (aPDT) leads to the generation of reactive oxygen species (ROS) that destroys bacterial cells in presence of a photosensitizer, visible light, and oxygen.<br><br>MATERIAL AND METHODS: We have taken Enterococcus faecalis and Streptococcus mutans as monospecies culture and their dualspecies culture biofilm. Antibacterial effect was evaluated by colony forming unit while antibiofilm action by crystal violet and congored binding assays.<br><br>RESULTS: We found that dual species biofilm are more resistant than monospecies biofilm and S. mutans shows dominance over E. faecalis in dual species biofilm, it inhibited the growth of E. faecalis in dual species biofilm. Antibiofilm efficacy of TBO also validated that dualspecies show less inhibition than monospecies biofilm this may be due to different EPS constitution in dualspecies biofilm, hence less inhibition was observed in EPS production of dualspecies biofilm than monospecies biofilm. Reactive oxygen species and singlet oxygen yield was found to be light dose dependent and antimicrobial photodynamic efficiency is directly related to the ROS production.<br><br>CONCLUSION: We conclude that dual species biofilm shows resistance over monospecies biofilm and S.mutans in dual species inhibits the growth of E. faecalis.},
}
@article {pmid31062019,
year = {2019},
author = {González, MJ and Da Cunda, P and Notejane, M and Zunino, P and Scavone, P and Robino, L},
title = {Fosfomycin tromethamine activity on biofilm and intracellular bacterial communities produced by uropathogenic Escherichia coli isolated from patients with urinary tract infection.},
journal = {Pathogens and disease},
volume = {77},
number = {3},
pages = {},
doi = {10.1093/femspd/ftz022},
pmid = {31062019},
issn = {2049-632X},
abstract = {Fosfomycin tromethamine (FT), an old antibiotic revived as a new strategy to overcome antibiotic resistance, is an excellent option for the treatment of lower urinary tract infection (UTI). During UTI, Escherichia coli produces biofilms and could invade the bladder epithelial cells, developing intracellular bacterial communities (IBC). The present work aimed to evaluate the activity of FT on biofilms and IBC from clinical isolates of E. coli. A total of 38 E. coli clinical UTI isolates previously characterized as biofilm and IBC producers were studied. FT susceptibility was evaluated and its activity on 48 h biofilm was determined by microtiter plate-based biofilm assay comparing three different antibiotic concentrations. Two UPEC strains were selected to evaluate FT activity on IBC in vitro using T24 bladder cells. The survival percentage of intracellular bacteria after 24 h exposure to FT was calculated and compared to the percentage of intracellular bacteria without antibiotic. All the strains were susceptible to FT. FT produced a significant reduction of biofilms at the three concentrations tested, compared to the control. However, no statistically effect on IBC was observed after 24 h of fosfomycin exposure in cell culture. FT is a good option for bacterial biofilm reduction within UTI. However, it does not affect IBC.},
}
@article {pmid31061169,
year = {2019},
author = {Gu, H and Lee, SW and Carnicelli, J and Jiang, Z and Ren, D},
title = {Antibiotic susceptibility of Escherichia coli cells during early-stage biofilm formation.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00034-19},
pmid = {31061169},
issn = {1098-5530},
abstract = {Bacteria form complex multicellular structures on solid surfaces called biofilms, which allow them to survive in harsh environments. A hallmark characteristic of mature biofilms is the high-level antibiotic tolerance (up to 1,000 times) compared to planktonic cells. Here, we report our new findings that biofilm cells are not always more tolerant to antibiotics than planktonic cells in the same culture. Specifically, Escherichia coli RP437 exhibited a dynamic change in antibiotic susceptibility during its early-stage biofilm formation. This phenomenon was not strain specific. Upon initial attachment, surface-associated cells became more sensitive to antibiotics than planktonic cells. By controlling the cell adhesion and cluster size using patterned E. coli biofilms, cells involved in the interaction between cell clusters during microcolony formation were found to be more susceptible to ampicillin than cells within clusters, suggesting a role of cell-cell interactions in biofilm-associated antibiotic tolerance. After this stage, biofilm cells became less susceptible to ampicillin and ofloxacin than planktonic cells. However, when the cells were detached by sonication, both antibiotics were more effective in killing the detached biofilm cells than the planktonic cells. Collectively, these results indicate that biofilm formation involves active cellular activities in adaption to the attached life form and interactions between cell clusters to build the complex structure of a biofilm, which can render these cells more susceptible to antibiotics. These findings shed new lights on bacterial antibiotic susceptibility during biofilm formation and can guide the design of better antifouling surfaces, e.g., those with micron-scale topographic structures to interrupt cell-cell interactions.IMPORTANCE Mature biofilms are known for their high-level tolerance to antibiotics; however, antibiotic susceptibility of sessile cells during early-stage biofilm formation is not well understood. In this study, we aim to fill this knowledge gap by following bacterial antibiotic susceptibility during early-stage biofilm formation. We found that the attached cells have a dynamic change in antibiotic susceptibility, and during certain phases, they can be more sensitive to antibiotics compared to planktonic counterparts in the same culture. Using surface chemistry controlled patterned biofilm formation, cell-surface and cell-cell interactions were found to be important to biofilm-associated antibiotic tolerance. Collectively, these findings provide new insights into biofilm physiology and reveal how adaptation to the attached life form affects antibiotic susceptibility of bacterial cells.},
}
@article {pmid31059933,
year = {2019},
author = {Johansen, MP and Cresswell, T and Davis, J and Howard, DL and Howell, NR and Prentice, E},
title = {Biofilm-enhanced adsorption of strong and weak cations onto different microplastic sample types: Use of spectroscopy, microscopy and radiotracer methods.},
journal = {Water research},
volume = {158},
number = {},
pages = {392-400},
doi = {10.1016/j.watres.2019.04.029},
pmid = {31059933},
issn = {1879-2448},
abstract = {The adsorption of metals and other elements onto environmental plastics has been previously quantified and is known to be enhanced by surface-weathering and development of biofilms. However, further biofilm-adsorption characterisation is needed with respect to the fate of radionuclides. This study uses spectroscopy, microscopy and radiotracer methods to investigate the adsorption capacity of relatively strong and weak cations onto different microplastic sample types that were conditioned in freshwater, estuarine and marine conditions although marine data were limited. Fourier-transform infrared spectroscopy confirmed that surface oxidation chemistry changes induced by gamma irradiation were similar to those resulting from environmental exposures. Microscopy elemental mapping revealed patchy biofilm development, which contained Si, Al, and O, consistent with microbial-facilitated capture of clays. The plastics+biofilm of all sample types had measurable adsorption for Cs and Sr radiotracers, suggesting environmental plastics act broadly as a sink for the key pervasive environmental radionuclides of 137Cs and 90Sr associated with releases from nuclear activities. Adsorption onto high-density polyethylene plastic types was greater than that on polypropylene. However, in most cases, the adsorption rates of all types of plastic+biofilm were much lower than those of reference sediments and roughly consistent with their relative exchangeable surface areas.},
}
@article {pmid31058104,
year = {2019},
author = {Xie, Z and Meng, K and Yang, X and Liu, J and Yu, J and Zheng, C and Cao, W and Liu, H},
title = {Identification of a Quorum Sensing System Regulating Capsule Polysaccharide Production and Biofilm Formation in Streptococcus zooepidemicus.},
journal = {Frontiers in cellular and infection microbiology},
volume = {9},
number = {},
pages = {121},
doi = {10.3389/fcimb.2019.00121},
pmid = {31058104},
issn = {2235-2988},
abstract = {Streptococcus zooepidemicus is an important opportunistic pathogen of several species including humans. This organism is also well-known as the main producing strain in industrial production of hyaluronic acid (HA), which is the component of its capsule polysaccharide. How its virulence and capsule polysaccharide production is regulated remains poorly understood. Intercellular chemical signaling among bacteria provides communities of microbes the opportunity to coordinate gene expression to facilitate group behavior, such as pathogenicity, capsule polysaccharide production, etc. Yet no conserved cell-to-cell signaling system has been elucidated in S. zooepidemicus. Encoded within the genome of S. zooepidemicus is one Rgg regulator encoding gene (rgg) with low similarity to both rgg2 and rgg3 from Streptococcus pyogenes. A small ORF (named as shp) encoding a novel short hydrophobic peptide (SHP) was found in the vicinity of rgg. We found that the active form of pheromone is short and hydrophobic (LLLLKLA), corresponding to the C terminal 7 amino acids of the pre-peptide Shp, which shows divergent sequence to all peptide pheromones reported in streptococci. In response to active SHP, Rgg functions as a transcriptional activator to induce the expression of shp, forming a positive feedback circuit. Bacteria social behaviors, such as capsule polysaccharide production and biofilm formation, were significantly affected when the rgg-shp pathway was inactivated. These data provide the first demonstration that Rgg/Shp signaling pathway comprises an active quorum sensing system in S. zooepidemicus.},
}
@article {pmid31057729,
year = {2019},
author = {Post, SJ and Shapiro, JA and Wuest, WM},
title = {Connecting iron acquisition and biofilm formation in the ESKAPE pathogens as a strategy for combatting antibiotic resistance.},
journal = {MedChemComm},
volume = {10},
number = {4},
pages = {505-512},
doi = {10.1039/c9md00032a},
pmid = {31057729},
issn = {2040-2511},
abstract = {The rise of antibiotic resistant bacteria has become a problem of global concern. Of particular interest are the ESKAPE pathogens, species with high rates of multi-drug resistant infections. Novel antibiotic mechanisms of action are necessary to compliment traditional therapeutics. Recent research has focused on targeting virulence factors as a method of combatting infection without creating selective pressure for resistance or damaging the host commensal microbiome. Some investigations into one such virulence behavior, iron acquisition, have displayed additional effects on another virulence behavior, biofilm formation. The use of exogenous iron-chelators, gallium as an iron mimic, and inhibition of siderophore-mediated iron acquisition are all strategies for disturbing iron-homeostasis that have implicated effects on biofilms. However, the exact nature of this connection remains ambiguous. Herein we summarize these findings and identify opportunities for further investigation.},
}
@article {pmid31057497,
year = {2019},
author = {Igbinosa, EO and Beshiru, A},
title = {Antimicrobial Resistance, Virulence Determinants, and Biofilm Formation of Enterococcus Species From Ready-to-Eat Seafood.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {728},
doi = {10.3389/fmicb.2019.00728},
pmid = {31057497},
issn = {1664-302X},
abstract = {Enterococcus species form an important population of commensal bacteria and have been reported to possess numerous virulence factors considered significantly important in exacerbating diseases caused by them. The present study was designed to characterize antibiotic-resistant and virulent enterococci from ready-to-eat (RTE) seafood. A total of 720 RTE shrimp samples comprising sauced shrimp (n = 288), boiled shrimp (n = 216), and smoked shrimp (n = 216) obtained from open markets in Delta State, Nigeria, were assessed. Standard classical methods and polymerase chain reaction (PCR) were used in identifying the Enterococcus species. Potential virulence factors (β-hemolysis, gelatinase activity, S-layer, and biofilm formation) were assessed using standard procedures. The antibiotic susceptibility profile of the identified enterococci isolates was assayed using the Kirby-Bauer disc diffusion method. PCR was further used to screen selected antibiotic resistance and virulence genes. Prevalence of Enterococcus species from shrimp varieties is as follows: sauced, 26 (9.03%); boiled, 6 (2.78%); and smoked, 27 (12.50%), with an overall prevalence of 59 (8.19%) based on the occurrence of black hallow colonies after incubation. Enterococcus species detected include E. faecalis, 17 (28.8%); E. faecium, 29 (49.2%); E. gallinarum, 6 (10.2%); E. casseliflavus, 2 (3.4%); E. hirae, 3 (5.1%); and E. durans, 2 (3.4%). Biofilm occurrence among the shrimp varieties is as follows: 19/26 (73.1%) for sauced shrimps, 5/6 (83.3%) for boiled shrimps, and 16/27 (59.3%) for smoked shrimps. The phenotypic expression of the enterococci virulence revealed the following: S-layer, 59 (100%); gelatinase production, 19 (32.2%); and β-hemolysis, 21 (35.6%). An average of 3-11 virulence genes were detected in the Enterococcus species. The resistance profile of Enterococcus species is as follows: erythromycin, 29 (49.2%); vancomycin, 22 (37.3%); and tetracycline, 27 (45.8%). The frequency of occurrence of antibiotic resistance genes from the phenotypic resistant enterococci isolates to the macrolide, glycopeptide, and tetracycline antibiotics is as follows: ermA, 13/29 (44.8%); vanA, 14/22 (63.6%); tetA, 14/27 (51.9%); tetM, 15/27 (55.6%); ermB, 4/29 (13.8%); and vanB, 5/22 (22.7%). Findings from this study reveal the antibiotic resistance of enterococci strains of such species as E. durans, E. casseliflavus, E. gallinarum, and E. hirae. This study further revealed that RTE food products are reservoirs of potential virulent enterococci with antibiotic-resistant capabilities. This provides useful data for risk assessment and indicates that these foods may present a potential public health risk to consumers.},
}
@article {pmid31055910,
year = {2019},
author = {Lee, JH and Kim, YG and Khadke, SK and Yamano, A and Watanabe, A and Lee, J},
title = {Nepodin inhibits biofilm formation by Candida albicans and polymicrobial microorganisms via hyphal growth suppression.},
journal = {ACS infectious diseases},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsinfecdis.9b00033},
pmid = {31055910},
issn = {2373-8227},
abstract = {Candida albicans is an opportunistic pathogenic yeast and is responsible for candidiasis. It readily colonizes host tissues and implant devices, and forms biofilms, which play an important role in pathogenesis and drug resistance. In this study, the antibiofilm, antihyphal, and antivirulence activities of nepodin isolated from Rumex japonicus roots, was investigated against a fluconazole-resistant C. albicans strain and polymicrobial microorganisms biofilm formation. Nepodin effectively inhibited C. albicans biofilm formation without affecting its planktonic cell growth. Also, Rumex root extract and nepodin both inhibited the hyphal growth and cell aggregation of C. albicans. Interestingly, nepodin also showed antibiofilm activities against Candida glabrata, Candida parapsilosis, Staphylococcus aureus and Acinetobacter baumannii strains and dual biofilms of C. albicans and S. aureus or A. baumannii, but not against Pseudomonas aeruginosa. Transcriptomic analysis performed by RNA-Seq and qRT-PCR showed nepodin repressed the expressions of several hypha/biofilm related genes (ECE1, HGT10, HWP1, and UME6) and increased the expressions of several transport genes (CDR4, CDR11, and TPO2), which supported phenotypic changes. Moreover, nepodin reduced C. albicans virulence in a nematode infection model and exhibited minimal cytotoxicity against the nematode and an animal cell line. These results demonstrate nepodin and Rumex root extract might be useful for controlling C. albicans infections and multispecies biofilms.},
}
@article {pmid31055471,
year = {2019},
author = {Lynch, C and O'Connor, JA and O'Brien, D and Vaughan, C and Bolton, D and Coffey, A and Lucey, B},
title = {First reported detection of biofilm formation by Campylobacter fetus during investigation of a case of prosthetic valve endocarditis.},
journal = {Journal of clinical pathology},
volume = {},
number = {},
pages = {},
doi = {10.1136/jclinpath-2018-205677},
pmid = {31055471},
issn = {1472-4146},
abstract = {AIMS: Campylobacter fetus subsp fetus (CFF) can cause intestinal illness, particularly in immunocompromised humans, with the potential to cause severe systemic infections. CFF is a zoonotic pathogen with a broad host range among farm animals and humans, inducing abortion in sheep and cows. The current paper describes a strain of CFF isolated from a patient with prosthetic valve endocarditis in Mercy University Hospital, Cork, Ireland, during 2017. Only five cases of C. fetus as a cause of prosthetic valve endocarditis have been reported in the literature, with no reports of biofilm formation within the species.<br><br>METHODS: The aetiological strain was speciated and subspeciated by the VITEK 2 NH card and matrix-assisted laser desorption ionisation time-of-flight mass spectrometry. CFF biofilm formation was analysed using a crystal violet staining method. C. jejuni National Collection of Type Cultures (NCTC) 11168 was used as a positive control organism. Strains were incubated statically in Mueller-Hinton broth and Mueller-Hinton broth supplemented with 0.025% sodium deoxycholate for 3 and 7 days at 37°C, microaerobically.<br><br>RESULTS: The CFF strain formed stronger attached biofilms on polystyrene plates on day 3 (72 hours) than the C. jejuni NCTC 11168 control strain, but were weaker than the control strain on day 7 in Mueller-Hinton broth. Monoculture of this C. fetus isolate was found to exist in three defined forms of biofilms (attached, air-liquid interface and floccules).<br><br>CONCLUSIONS: This clinically significant C. fetus isolate showed considerable biofilm-forming capability, which we suggest conferred a survivalist advantage, contributing to the genesis of infective prosthetic valve endocarditis.},
}
@article {pmid31054395,
year = {2019},
author = {Peng, L and Ngo, HH and Song, S and Xu, Y and Guo, W and Liu, Y and Wei, W and Chen, X and Wang, D and Ni, BJ},
title = {Heterotrophic denitrifiers growing on soluble microbial products contribute to nitrous oxide production in anammox biofilm: Model evaluation.},
journal = {Journal of environmental management},
volume = {242},
number = {},
pages = {309-314},
doi = {10.1016/j.jenvman.2019.04.084},
pmid = {31054395},
issn = {1095-8630},
abstract = {In this work, a model framework was constructed to assess and predict nitrous oxide (N2O) production, substrate and microbe interactions in an anammox biofilm bioreactor. The anammox kinetics were extended by including kinetics of autotrophic soluble microbial products (SMP) formation, which consisted of utilization-associated products (UAP) and biomass-associated products (BAP). Heterotrophic bacteria growing on UAP, BAP and decay released substance (SS) were modelled to perform four-step sequential reductions from nitrate to dinitrogen gas. N2O was modelled as an intermidiate of heterotrophic denitrification via three pathways with UAP, BAP and SS as the electron donors. The developed model framework was evaluated using long-term operational data from an anammox biofilm reactor and satisfactorily reproduced effluent nitrogen and SMP as well as N2O emission factors under different operational conditions. The modeling results revealed that N2O was mainly produced with UAP as the electron donor while BAP and SS play minor roles. Heterotrophic denitrifiers growing on UAP would significantly contribute to N2O emission from anammox biofilm reactor even though heterotrophs only account for a relatively small fraction of active biomass in the anammox biofilm. Comprehensive simulations were conducted to investigate the effects of N loading rate and biofilm thickness, which indicated that maintaining a low N loading rate and a thick biofilm thickness were essential for high total nitrogen removal efficiency and low N2O emission.},
}
@article {pmid31054134,
year = {2019},
author = {Babbar, A and Barrantes, I and Pieper, DH and Itzek, A},
title = {Superantigen SpeA attenuates the biofilm forming capacity of Streptococcus pyogenes.},
journal = {Journal of microbiology (Seoul, Korea)},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12275-019-8648-z},
pmid = {31054134},
issn = {1976-3794},
abstract = {Beta haemolytic Group A streptococcus (GAS) or Streptococcus pyogenes are strict human pathogens responsible for mild to severe fatal invasive infections. Even with enormous number of reports exploring the role of S. pyogenes exotoxins in its pathogenesis, inadequate knowledge on the biofilm process and the potential role of exotoxins in bacterial dissemination from matured biofilms has been a hindrance in development of effective and targeted treatments. Therefore, the present study was aimed in investigating the uncharted role of these exotoxins in biofilm process. Through our study the putative role of ciaRH in the SpeA dependent ablation of biofilm formation could be speculated and thus helping in bacterial dissemination. The seed-dispersal effect of SpeA was time and concentration dependent and seen to be consistent within various streptococcal species. Transcriptome analysis of SpeA treated S. pyogenes biofilms revealed the involvement of many transcriptional regulators (ciaRH) and response genes (luxS, shr, shp, SPy_0572), hinting towards specific mechanisms underlying the dispersal effect by SpeA. This finding opens up a discussion towards understanding a new mechanism involved in the pathogenesis of Streptococcus pyogenes and might help in understanding the bacterial infections in a better way.},
}
@article {pmid31054133,
year = {2019},
author = {Taha, MN and Saafan, AE and Ahmedy, A and El Gebaly, E and Khairalla, AS},
title = {Two novel synthetic peptides inhibit quorum sensing-dependent biofilm formation and some virulence factors in Pseudomonas aeruginosa PAO1.},
journal = {Journal of microbiology (Seoul, Korea)},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12275-019-8548-2},
pmid = {31054133},
issn = {1976-3794},
abstract = {Quorum sensing (QS) regulates virulence factor expression in Pseudomonas aeruginosa. Inhibiting the QS-controlled virulence factors without inhibiting the growth of P. aeruginosa is a promising approach for overcoming the widespread resistance of P. aeruginosa. This study was proposed to investigate the effects of two novel synthetic peptides on the biofilm development and virulence factor production of P. aeruginosa. The tested strain was P. aeruginosa PAO1. The results indicated that both of the synthetic peptides (LIVRHK and LIVRRK) inhibited (P < 0.05) the formation of biofilms and the production of virulence factors, including pyocyanin, protease, and rhamnolipids, without inhibiting the growth of PAO1. Additionally, we detected transcriptional changes related to QS and found a significant reduction in the levels of gene expression of lasI, lasR, rhlI, and rhlR. This study demonstrates that LIVRRK and LIVRHK are novel synthetic peptides that can act as potent inhibitors of QS-regulated virulence factors in P. aeruginosa. Moreover, these synthetic peptides have potential applications in the treatment of biofilmrelated diseases. Both peptides may be able to control chronic infections and biofilm-associated problems of P. aeruginosa.},
}
@article {pmid31053580,
year = {2019},
author = {Gu, D and Zhang, J and Hao, Y and Xu, R and Zhang, Y and Ma, Y and Wang, Q},
title = {Alternative sigma factor RpoX is a part of RpoE regulon and plays distinct roles in stress response, motility, biofilm formation and hemolytic activities in the marine pathogen Vibrio alginolyticus.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.00234-19},
pmid = {31053580},
issn = {1098-5336},
abstract = {Vibrio alginolyticus is one of the most abundant microorganisms in marine environments and is also an opportunistic pathogen mediating high-mortality vibriosis in marine animals. Alternative sigma factors play essential roles in bacterial pathogens in the adaptation to environmental changes during infection and the adaptation to various niches, but little is known about them for V. alginolyticus Our previous investigation indicated that the transcript level of the gene rpoX significantly decreased in an RpoE mutant. Here, we found that rpoX was highly expressed in response to high-temperature and low-osmotic stress and was under the direct control of the alternative sigma factor RpoE and its own product RpoX. Moreover, the RNA-seq results showed that RpoE and RpoX had different regulons, although they coregulated 105 genes at high temperature (42°C), including genes associated with biofilm formation, motility, virulence, regulatory factors and stress response. RNA-seq and ChIP-seq as well as EMSA analyses revealed the distinct binding motifs of RpoE and RpoX proteins. Furthermore, qRT-PCR analysis also confirmed that RpoX can upregulate genes associated with flagella, biofilm formation and hemolytic activities at higher temperatures. rpoX abrogation does not appear to attenuate virulence towards model fish at normal temperature. Collectively, this study demonstrated the regulatory cascades of RpoE and an alternative sigma factor, RpoX, in response to heat and osmotic stresses and their distinct and overlapping roles in pathogenesis and stress responses in the marine bacterium V. alginolyticusIMPORTANCE The alternative sigma factor RpoE is essential for the virulence of Vibrio alginolyticus towards marine fish, coral and other animals in response to sea surface temperature increases. In this study, we characterized another alternative sigma factor, RpoX, which is induced at high temperatures and under low-osmotic conditions. The expression of rpoX is under the tight control of RpoE and RpoX. Although RpoE and RpoX coregulate 105 genes, they are programming different regulatory functions in stress responses and virulence in V. alginolyticus These findings illuminated the RpoE-RpoX-centered regulatory cascades and their distinct and overlapping regulatory roles in V. alginolyticus, which facilitates to unravel the mechanisms by which the bacterium causes diseases in various sea animals in response to temperature fluctuations as well as to develop appropriate strategies to tackle the infections by the bacterium.},
}
@article {pmid31052271,
year = {2019},
author = {Bahamondez-Canas, TF and Heersema, LA and Smyth, HDC},
title = {Current Status of In Vitro Models and Assays for Susceptibility Testing for Wound Biofilm Infections.},
journal = {Biomedicines},
volume = {7},
number = {2},
pages = {},
doi = {10.3390/biomedicines7020034},
pmid = {31052271},
issn = {2227-9059},
support = {DGE-1610403//National Science Foundation/ ; },
abstract = {Biofilm infections have gained recognition as an important therapeutic challenge in the last several decades due to their relationship with the chronicity of infectious diseases. Studies of novel therapeutic treatments targeting infections require the development and use of models to mimic the formation and characteristics of biofilms within host tissues. Due to the diversity of reported in vitro models and lack of consensus, this review aims to provide a summary of in vitro models currently used in research. In particular, we review the various reported in vitro models of Pseudomonas aeruginosa biofilms due to its high clinical impact in chronic wounds and in other chronic infections. We assess advances in in vitro models that incorporate relevant multispecies biofilms found in infected wounds, such as P. aeruginosa with Staphylococcus aureus, and additional elements such as mammalian cells, simulating fluids, and tissue explants in an attempt to better represent the physiological conditions found at an infection site. It is hoped this review will aid researchers in the field to make appropriate choices in their proposed studies with regards to in vitro models and methods.},
}
@article {pmid31050052,
year = {2019},
author = {Guo, J and Qin, S and Wei, Y and Liu, S and Peng, H and Li, Q and Luo, L and Lv, M},
title = {Silver nanoparticles exert concentration-dependent influences on biofilm development and architecture.},
journal = {Cell proliferation},
volume = {},
number = {},
pages = {e12616},
doi = {10.1111/cpr.12616},
pmid = {31050052},
issn = {1365-2184},
support = {//LU JIAXI International team program supported by the K.C. Wong Education Foundation and CAS/ ; QYZDJ-SSW-SLH031//the Key Research Program of Frontier Sciences, CAS/ ; 2016YFA0201200//the National Key R&amp;D Program of China/ ; 2016YFA0400900//the National Key R&amp;D Program of China/ ; U1632125//National Natural Science Foundation of China/ ; 21705159//National Natural Science Foundation of China/ ; 61571278//National Natural Science Foundation of China/ ; 31571014//National Natural Science Foundation of China/ ; },
abstract = {OBJECTIVES: To investigate the impact of silver nanoparticles (AgNPs) on the biofilm growth and architecture.<br><br>MATERIALS AND METHODS: Silver nitrate was reduced by d-maltose to prepare AgNPs in the presence of ammonia and sodium hydroxide. The physicochemical properties of AgNPs were characterized by transmission electron microscopy, ultraviolet-visible spectroscopy and inductively coupled plasma mass spectrometry. The development of biofilm with and without AgNPs was explored by crystal violet stain. The structures of mature biofilm were visually studied by confocal laser scanning microscopy and scanning electron microscopy. Bacterial cell, polysaccharide and protein within biofilm were assessed quantitatively by colony-counting method, phenol-sulphuric acid method and Bradford assay, respectively.<br><br>RESULTS: The spherical AgNPs (about 30 nm) were successfully synthesized. The effect of AgNPs on Pseudomonas aeruginosa biofilm development was concentration-dependent. Biofilm was more resistant to AgNPs than planktonic cells. Low doses of AgNPs exposure remarkably delayed the growth cycle of biofilm, whereas high concentration (18 μg/mL) of AgNPs fully prevented biofilm development. The analysis of biofilm architecture at the mature stage demonstrated that AgNPs exposure at all concentration led to significant decrease of cell viability within treated biofilms. However, sublethal doses of AgNPs increased the production of both polysaccharide and protein compared to control, which significantly changed the biofilm structure.<br><br>CONCLUSIONS: AgNPs exert concentration-dependent influences on biofilm development and structure, which provides new insight into the role of concentration played in the interaction between antibacterial nanoparticles and biofilm, especially, an ignored sublethal concentration associated with potential unintended consequences.},
}
@article {pmid31044250,
year = {2019},
author = {Alcaraz, E and García, C and Friedman, L and de Rossi, BP},
title = {The rpf/DSF signalling system of Stenotrophomonas maltophilia positively regulates biofilm formation, production of virulence-associated factors and β-lactamase induction.},
journal = {FEMS microbiology letters},
volume = {366},
number = {6},
pages = {},
doi = {10.1093/femsle/fnz069},
pmid = {31044250},
issn = {1574-6968},
abstract = {Stenotrophomonas maltophilia is a multidrug-resistant opportunistic pathogen. S. maltophilia quorum-sensing system is mediated by the diffusible signal factor (DSF), which synthesis depends on rpfF. It has been reported that rpfF disruption in S. maltophilia K279a leads to a loss of DSF synthesis, reduced levels of extracellular protease, swarming motility and virulence in the Galleria mellonella model. The aim of this work was to attain a deeper knowledge of the role of the rpf/DSF signalling system in S. maltophilia biofilm formation, phenotypic traits associated with biofilm development and virulence and antimicrobial susceptibility. To this end, comparative studies were conducted on S. maltophilia K279a and K279arpfF. The results presented here put in evidence the positive role of DSF in bacterial growth, biofilm formation, swimming and twitching motilities, DNAse, lipases and siderophores production as well as resistance to oxidative stress. Interestingly, DSF seems to be essential for the development of the spatially organised structure seen in mature biofilms. Therefore, DSF from S. maltophlia K279a positively regulates biofilm formation and virulence. Furthermore, DSF is necessary for the induction of L1 and L2 β-lactamase production in K279a. This is the first evidence of the role of the rpf/DSF signalling system in S. maltophilia β-lactam resistance.},
}
@article {pmid31042554,
year = {2019},
author = {de Carvalho Leonel, L and Carvalho, ML and da Silva, BM and Zamuner, S and Alberto-Silva, C and Costa, MS},
title = {Photodynamic Antimicrobial Chemotherapy (PACT) using Methylene blue inhibits the viability of the biofilm produced by Candida albicans.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.04.026},
pmid = {31042554},
issn = {1873-1597},
abstract = {BACKGROUND: Candida albicans is an opportunistic fungus, an etiological agent of human infections, presenting high rates of morbidity and mortality. The resistance of C. albicans to conventional therapies has been reported due to the extensive use of conventional antifungals. Photodynamic antimicrobial chemotherapy (PACT) is a technique that combines a visible light with a specific wavelength and a photosensitizer, producing ROS and permanent damages in the treated cells.<br><br>METHODS: In this work, the effects of PACT, using Methylene Blue (MB), as a photosensitizer, on C. albicans development were studied.<br><br>RESULTS: Significant reduction in both cell growth and biofilm formation after PACT were observed, in a dependent manner on both MB concentration and fluence. In the presence of MB 0.02 mg/mL, it was observed inhibition in biofilm formation of ˜58, 70 and 74%, using fluences of 10, 20 and 30 J/cm2, respectively. Also, it was observed inhibition of 54, 66 and 55% in the presence of MB 0.01, 0.02 and 0.05 mg/mL, respectively in the viability of biofilm produced by C. albicans. The number of both yeast and filaments present in the structure of biofilm were reduced after PACT. Furthermore, PACT changed the growth kinetics of C. albicans. Interestingly, we demonstrated increase in the extent of lag phase and an alteration in the profile of the exponential phase after PACT.<br><br>CONCLUSIONS: Taken together, these results indicate the potential PACT effects using MB to decrease the C. albicans development.},
}
@article {pmid31040831,
year = {2019},
author = {Crenier, C and Sanchez-Thirion, K and Bec, A and Felten, V and Ferriol, J and González, AG and Leflaive, J and Perrière, F and Ten-Hage, L and Danger, M},
title = {Interactive Impacts of Silver and Phosphorus on Autotrophic Biofilm Elemental and Biochemical Quality for a Macroinvertebrate Consumer.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {732},
doi = {10.3389/fmicb.2019.00732},
pmid = {31040831},
issn = {1664-302X},
abstract = {Autotrophic biofilms are complex and fundamental biological compartments of many aquatic ecosystems. In particular, these biofilms represent a major resource for many invertebrate consumers and the first ecological barrier against toxic metals. To date, very few studies have investigated the indirect effects of stressors on upper trophic levels through alterations of the quality of biofilms for their consumers. In a laboratory study, we investigated the single and combined effects of phosphorus (P) availability and silver, a re-emerging contaminant, on the elemental [carbon (C):nitrogen (N):P ratios] and biochemical (fatty acid profiles) compositions of a diatom-dominated biofilm initially collected in a shallow lake. We hypothesized that (1) P and silver, through the replacement of diatoms by more tolerant primary producer species, reduce the biochemical quality of biofilms for their consumers while (2) P enhances biofilm elemental quality and (3) silver contamination of biofilm has negative effects on consumers life history traits. The quality of biofilms for consumers was assessed for a common crustacean species, Gammarus fossarum, by measuring organisms' survival and growth rates during a 42-days feeding experiment. Results mainly showed that species replacement induced by both stressors affected biofilm fatty acid compositions, and that P immobilization permitted to achieve low C:P biofilms, whatever the level of silver contamination. Gammarids growth and survival rates were not significantly impacted by the ingestion of silver-contaminated resource. On the contrary, we found a significant positive relationship between the biofilm P-content and gammarids growth. This study underlines the large indirect consequences stressors could play on the quality of microbial biomass for consumers, and, in turn, on the whole food web.},
}
@article {pmid31040399,
year = {2019},
author = {Hold, GL and Allen-Vercoe, E},
title = {Gut microbial biofilm composition and organisation holds the key to CRC.},
journal = {Nature reviews. Gastroenterology &amp; hepatology},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41575-019-0148-4},
pmid = {31040399},
issn = {1759-5053},
}
@article {pmid31038914,
year = {2019},
author = {Nagay, BE and Dini, C and Cordeiro, JM and Ricomini-Filho, AP and de Avila, ED and Rangel, EC and da Cruz, NC and Barao, VAR},
title = {Visible-light-induced Photocatalytic and Antibacterial Activity of TiO2 Codoped with Nitrogen and Bismuth: New Perspective to Control Implant-biofilm-related Disease.},
journal = {ACS applied materials &amp; interfaces},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsami.9b03311},
pmid = {31038914},
issn = {1944-8252},
abstract = {Biofilm-associated disease is one of the main cause of implant failure. Currently, the development of implant surface treatment goes beyond the osseointegration process, and focuses on the creation of surfaces with antimicrobial action and with the possibility to be reactivated (i.e. light source activation). Titanium dioxide (TiO2), an excellent photocatalyst used for photocatalytic antibacterial applications, could be a great alternative, but its efficiency is limited to the ultraviolet (UV) range of the electromagnetic spectrum. Since UV radiation has carcinogenic potential, we created a functional TiO2 coating codoped with nitrogen and bismuth via the plasma electrolytic oxidation (PEO) of titanium to achieve an antibacterial effect under visible light with reactivation potential. A complex surface topography was demonstrated by scanning electron microscopy and 3D confocal laser scanning microscopy. Additionally, PEO-treated surfaces showed greater hydrophilicity and albumin adsorption compared to control, untreated titanium. Bismuth incorporation shifted the band gap of TiO2 to the visible region and facilitated the higher degradation of methyl orange (MO) in the dark, with a greater reduction in the concentration of MO after visible-light irradiation even after 72 h of aging. These results were consistent with the in vitro antibacterial effect, where samples with nitrogen and bismuth in their composition showed the greatest bacterial reduction after 24 h of dual-species biofilm formation (Streptococcus sanguinis and Actinomyces naeslundii) in darkness with a superior effect at 30 min of visible-light irradiation. In addition, such coating presents a reusable photocatalytic potential and good biocompatibility by presenting non-cytotoxicity effect on human gingival fibroblast cells. Therefore, nitrogen and bismuth incorporation in TiO2 via PEO can be considered a promising alternative for dental implants application with antibacterial properties in darkness, with a stronger effect after visible-light application.},
}
@article {pmid31038103,
year = {2019},
author = {El-Khatib, M and Tetreau, G and Colletier, JP},
title = {[Porins: a vital role and a social link within the bacterial biofilm of P. stuartii].},
journal = {Medecine sciences : M/S},
volume = {35},
number = {4},
pages = {291-295},
doi = {10.1051/medsci/2019059},
pmid = {31038103},
issn = {1958-5381},
}
@article {pmid31037765,
year = {2019},
author = {Vinod Kumar, K and Lall, C and Raj, RV and Vijayachari, P},
title = {Coaggregation and biofilm formation of Leptospira with Staphylococcus aureus.},
journal = {Microbiology and immunology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1348-0421.12679},
pmid = {31037765},
issn = {1348-0421},
support = {Intramural Grant//Indian Council of Medical Research/ ; },
abstract = {It is not known how Leptospira react to wound or a cut infected with microbes, such as pathogenic Staphylococcus, or their common habitat on oral or nasal mucosal membranes. In the present study, Staphylococcus aureus MTCC-737 showed strong co-aggregation with leptospiral strains (>75%, visual score of + 4) in vitro. All tested strains of Leptospira were able to form biofilm with S. aureus. Scanning electron microscopy analysis revealed intertwined networks of attached cells of L. interrogans and S. aureus, thus providing evidence of a matrix-like structure. This phenomenon may have implications in Leptospira infection, which occurs via cuts and wounds of the skin.},
}
@article {pmid31036689,
year = {2019},
author = {Vargas-Cruz, N and Reitzel, RA and Rosenblatt, J and Chaftari, AM and Wilson Dib, R and Hachem, R and Kontoyiannis, DP and Raad, II},
title = {Nitroglycerin-Citrate-Ethanol (NiCE) Catheter Lock Solution is Highly Effective for in vitro Eradication of Candida auris Biofilm.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.00299-19},
pmid = {31036689},
issn = {1098-6596},
abstract = {Candida auris poses emerging risks for causing severe central line associated bloodstream infections (CLABSIs). We tested in vitro, the ability of antifungal lock solutions to rapidly eradicate C. auris biofilms. Liposomal amphotericin B, amphotericin B deoxycholate, fluconazole, voriconazole, micafungin, caspofungin and anidulafungin failed to completely eradicate all ten tested C. auris biofilms. Conversely, nitroglycerin-citrate-ethanol (NiCE) catheter lock solution was able to completely eradicate all replicates for all C. auris biofilms tested.},
}
@article {pmid31035915,
year = {2019},
author = {Perera, M and Wijayarathna, D and Wijesundera, S and Chinthaka, M and Seneviratne, G and Jayasena, S},
title = {Biofilm mediated synergistic degradation of hexadecane by a naturally formed community comprising Aspergillus flavus complex and Bacillus cereus group.},
journal = {BMC microbiology},
volume = {19},
number = {1},
pages = {84},
doi = {10.1186/s12866-019-1460-4},
pmid = {31035915},
issn = {1471-2180},
support = {AP/3/2/2014/RG/12//University of Colombo/ ; },
abstract = {BACKGROUND: The hydrophobic nature of hydrocarbons make them less bioavailable to microbes, generally leading to low efficiency in biodegradation. Current bioremediation strategies for hydrocarbon contamination, uses induced mixed microbial cultures. This in-vitro study demonstrates the utilization of naturally occurring communities in suitable habitats for achieving highly efficient, synergistic degradation of hydrocarbons in a simple community structure without additives.<br><br>METHODS: Enrichment media supplemented with 1% (7652.53 mg/L) hexadecane (HXD) as the sole carbon source were inoculated with samples of soil with waste polythene, collected from a municipal landfill in order to isolate microbial communities. Gas Chromatography-Mass Spectrometry (GC-MS) analysis was performed on HXD grown co-cultures and individual counterparts after 14 days incubation and percentage degradation was calculated. Microbes were identified using 16S rRNA gene and Internal Transcribed Spacer region sequencing. Biofilm formation was confirmed through scanning electron microscopy, in the most efficient community.<br><br>RESULTS: Three mixed communities (C1, C2 and C3) that demonstrated efficient visual disintegration of the HXD layer in the static liquid cultures were isolated. The C1 community showed the highest activity, degrading > 99% HXD within 14 days. C1 comprised of a single fungus and a bacterium and they were identified as a Bacillus sp. MM1 and an Apsergillus sp. MM1. The co-culture and individual counterparts of the C1 community were assayed for HXD degradation by GC-MS. Degradation by the fungal and bacterial monocultures were 52.92 ± 8.81% and 9.62 ± 0.71% respectively, compared to 99.42 ± 0.38% by the co-culture in 14 days. This proved the synergistic behavior of the community. Further, this community demonstrated the formation of a biofilm in oil-water interface in the liquid medium. This was evidenced from scanning electron microscopy (SEM) showing the Bacillus cells attached on to Aspergillus mycelia.<br><br>CONCLUSIONS: This study demonstrates the utilization of naturally formed fungal-bacterial communities for enhanced biodegradation of hydrocarbons such as hexadecane and reports for the first time, synergistic degradation of hexadecane through biofilm formation, by a community comprising of Bacillus cereus group and Aspergillus flavus complex.},
}
@article {pmid31034965,
year = {2019},
author = {Yonezawa, H and Osaki, T and Hojo, F and Kamiya, S},
title = {Effect of Helicobacter pylori biofilm formation on susceptibility to amoxicillin, metronidazole and clarithromycin.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.micpath.2019.04.030},
pmid = {31034965},
issn = {1096-1208},
abstract = {The human gastric pathogen Helicobacter pylori forms biofilms in vitro and in vivo. We previously demonstrated that H. pylori biofilm formation in vitro decreased its susceptibility to clarithromycin (CAM). The aim of this study was to evaluate the effects of biofilm formation on amoxicillin (AMPC) and metronidazole (MNZ) susceptibility. In addition, we assessed the influence of biofilms of CAM resistant H. pylori on CAM susceptibility. It was shown that high levels of efflux pump gene transcripts were detected in biofilm cells of all H. pylori strains used in this study. H. pylori biofilm biomass was significantly decreased compared to initial biomass after treatment with the minimum inhibitory concentration (MIC) of AMPC. Similarly, the biofilm biomass of H. pylori decreased after treatment with MIC of MNZ, although the difference was not statistically significant. However, minimum bactericidal concentrations (MBCs) of AMPC or MNZ to biofilm cells were higher than those of planktonic cells. The biofilm biomasses of all of the CAM resistant strains were significantly decreased compared to initial biomass after treatment with 2x MIC of CAM. However, the viability of the CAM treated biofilm cells with 2x MIC of CAM was not significantly reduced compared to initial cell numbers with the exception of one strain. The viability of biofilm cells of all strains was higher than that of planktonic cells after treatment with various concentrations of CAM. These results indicate that biofilm cells were more resistant to these antibiotics than planktonic cells and that the assessment of the ability to form biofilms in H. pylori is important for eradication of this microorganism.},
}
@article {pmid31034083,
year = {2019},
author = {Bernardi, S and Continenza, MA and Al-Ahmad, A and Karygianni, L and Follo, M and Filippi, A and Macchiarelli, G},
title = {Streptococcus spp. and Fusobacterium nucleatum in tongue dorsum biofilm from halitosis patients: a fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) study.},
journal = {The new microbiologica},
volume = {41},
number = {2},
pages = {},
pmid = {31034083},
issn = {1121-7138},
abstract = {The present study involved a qualitative and quantitative evaluation of tongue dorsum biofilms sampled from halitosis patients and healthy volunteers. The aim of the study was to quantify the distribution of Streptococcus spp. and Fusobacterium nucleatum within the oral halitosis biofilm in order to highlight the role of these bacterial members in halitosis. Tongue plaque samples from four halitosis-diagnosed patients and four healthy volunteers were analyzed and compared. The visualization and quantification of the tongue dorsum biofilm was performed combining fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM). Eubacteria, Streptococcus spp. and Fusobacterium nucleatum were stained using specific fluorescent probes. For a comparison of the two tested biofilm groups the Wilcoxon rank-sum test was used. Morphological analysis by CLSM illustrated the distribution of the species which were tracked. Streptococcus spp. appeared to be enclosed within the samples and always associated to F. nucleatum. Furthermore, compared to the control group the biofilm within the halitosis group contained significantly higher proportions of F. nucleatum and Streptococcus spp., as revealed by the FISH and CLSM-analysis. The total microbial load and relative proportions of F. nucleatum and Streptococcus spp. can be considered as causative factors of halitosis and thus, as potential treatment targets.},
}
@article {pmid31033962,
year = {2019},
author = {Danikowski, KM and Cheng, T},
title = {Colorimetric Analysis of Alkaline Phosphatase Activity in S. aureus Biofilm.},
journal = {Journal of visualized experiments : JoVE},
volume = {},
number = {146},
pages = {},
doi = {10.3791/59285},
pmid = {31033962},
issn = {1940-087X},
abstract = {Alkaline phosphatase (ALP) is a common enzyme expressed in both prokaryotic and eukaryotic cells. It catalyzes the hydrolysis of phosphate monoesters from many molecules at basic pH and plays an indispensable role in phosphate metabolism. In humans, eukaryotic ALP is one of the most frequently used enzymatic signals in diagnosing various diseases, such as cholestasis and rickets. In S. aureus, ALP is detected exclusively on the cell membrane; it is also expressed as a secretory form as well. Yet, little is known about its function in biofilm formation. The purpose of this manuscript is to develop a quick and reliable assay to measure ALP activity in S. aureus biofilm that does not require protein isolation. Using p-nitrophenyl phosphate (pNPP) as a substrate, we measured ALP activity in S. aureus biofilm formed in 96-well tissue culture plates. Activity was based on the formation of the soluble reaction product measured by 405 nm absorbance. The high throughput nature of the 96 well tissue culture plate method provides a sensitive and reproducible method for ALP activity assays. The same experimental set up can also be extended to measure other extracellular molecular markers related to biofilm formation.},
}
@article {pmid31033283,
year = {2019},
author = {Benoit, DSW and Sims, KR and Fraser, D},
title = {Nanoparticles for Oral Biofilm Treatments.},
journal = {ACS nano},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsnano.9b02816},
pmid = {31033283},
issn = {1936-086X},
abstract = {Pathogenic oral biofilms are universal, chronic, and costly. Despite advances in understanding the mechanisms of biofilm formation and persistence, novel and effective treatment options remain scarce. Nanoparticle-mediated eradication of the biofilm matrix and resident bacteria holds great potential. In particular, nanoparticles that target specific microbial and biofilm features utilizing nontoxic materials are well-suited for clinical translation. However, much work remains to characterize the local and systemic effects of therapeutic agents that are topically applied to chronic biofilms, such as those that cause dental caries. In this Perspective, we summarize the pathogenesis of oral biofilms, describe current and future nanoparticle-mediated treatment approaches, and highlight outstanding questions that are paramount to answer for effectively targeting and treating oral biofilms.},
}
@article {pmid31033028,
year = {2019},
author = {Tuna, T and Kuhlmann, L and Bishti, S and Sirazitdinova, E and Deserno, T and Wolfart, S},
title = {Removal of simulated biofilm at different implant crown designs with interproximal oral hygiene aids. An in vitro study.},
journal = {Clinical oral implants research},
volume = {},
number = {},
pages = {},
doi = {10.1111/clr.13448},
pmid = {31033028},
issn = {1600-0501},
abstract = {OBJECTIVES: To compare the removal of simulated biofilm at two different implant-supported restoration designs with various interproximal oral hygiene aids.<br><br>METHODS: Mandibular models with a missing first molar were fabricated and provided with single implant analogues (centrally or distally placed) and two different crown designs (CCD: conventional and ACD: alternative crown design). Occlusion spray was applied to the crowns to simulate artificial biofilm. Thirty participants (dentists, dental hygienists and laypersons) were equally divided and asked to clean the interproximal areas with five different cleaning devices to further evaluate if there were differences in their cleaning ability. The outcome was measured via standardized photos and the cleaning ratio, representing the cleaned surfaces in relation to the respective crown surface. Statistical analysis was performed by linear mixed-effects model with fixed effects for cleaning tools, surfaces, crown design and type of participant, and random effects for crowns.<br><br>RESULTS: The mean cleaning ratio for the investigated tools and crown designs were (in%): Super floss: 76±13/ACD and 57±14/CCD (highest cleaning efficiency), followed by dental floss: 66±13/ACD and 56±15/CCD, interdental brush: 55±10/ACD and 45±9/CCD, electric interspace brush: 31±10/ACD and 30±1/CCD, microdroplet floss: 8±9/ACD and 9±8/CCD. There was evidence of an overall effect of each factor &quot;cleaning tool&quot;, &quot;surface&quot;, &quot;crown design&quot; and &quot;participant&quot; (p<0.0001).<br><br>CONCLUSIONS: ACD allowed more removal of the artificial biofilm than CCD with Super floss, dental floss and interdental brush. Flossing and interproximal brushing were the most effective cleaning methods. A complete removal of the artificial biofilm could not be achieved in any group. This article is protected by copyright. All rights reserved.},
}
@article {pmid31031431,
year = {2019},
author = {Bhatwalkar, SB and Gound, SS and Mondal, R and Srivastava, RK and Anupam, R},
title = {Anti-biofilm and Antibacterial Activity of Allium sativum Against Drug Resistant Shiga-Toxin Producing Escherichia coli (STEC) Isolates from Patient Samples and Food Sources.},
journal = {Indian journal of microbiology},
volume = {59},
number = {2},
pages = {171-179},
doi = {10.1007/s12088-019-00784-3},
pmid = {31031431},
issn = {0046-8991},
abstract = {Escherichia coli (E. coli) colonizes human intestinal tract and is usually harmless to the host. However, several strains of E. coli have acquired virulent genes and could cause enteric diseases, urinary tract and even brain infections. Shiga toxin producing Escherichia coli (STEC) is an enterohaemorrhagic E. coli (EHEC) which can result in bloody diarrhoea and could potentially lead to deadly heamolytic uremic syndrome (HUS). STEC is one of the important food borne pathogens that causes food poisoning leading to diarrhoea and number of STEC outbreaks have occurred across the world. The use of standard antibiotics to treat STEC infection is not recommended as it increases the production of shiga toxin which could lead to HUS. Therefore, use of alternative approaches which include use of plant products to treat STEC infections have been gaining attention. The objective of this study was to evaluate the antibacterial and anti-biofilm activity of garlic (Allium sativum) against STEC strains isolated from various patient and food samples using in vitro assays. The microbiological isolation of STEC from various patient and food samples resulted in eight STEC isolates of which seven strains were multidrug resistant. Antibacterial assay results indicated that all the strains exhibited dose dependent sensitivity towards garlic with zone of inhibition diameters ranging from 7 to 24 mm with 15 µl of fresh garlic extract (FGE). Minimum inhibitory concentration (MIC) of FGE for isolates ranged from 30 to 140 µl/ml. Interestingly, the biofilm formation of all isolates in presence of 4% of FGE decreased by 35 to 59%. FTIR analysis indicated that treatment with 1% FGE results in compositional and content changes in the biofilm. In addition, the total carbohydrate content of biofilm was reduced by 40% upon 1% FGE treatment. The results of the present study report for the first time the antibacterial and anti-biofilm activity of garlic against STEC. The findings will enable development of novel garlic organosulfide based drugs for the prevention and treatment of STEC infections.},
}
@article {pmid31029662,
year = {2019},
author = {Noverr, MC and Fidel, PL},
title = {Questions remain regarding the presence of fungal species biofilm in women with vulvovaginal candidiasis.},
journal = {American journal of obstetrics and gynecology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ajog.2019.04.017},
pmid = {31029662},
issn = {1097-6868},
}
@article {pmid31029348,
year = {2019},
author = {Daengngam, C and Lethongkam, S and Srisamran, P and Paosen, S and Wintachai, P and Anantravanit, B and Vattanavanit, V and Voravuthikunchai, S},
title = {Green fabrication of anti-bacterial biofilm layer on endotracheal tubing using silver nanoparticles embedded in polyelectrolyte multilayered film.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {101},
number = {},
pages = {53-63},
doi = {10.1016/j.msec.2019.03.061},
pmid = {31029348},
issn = {1873-0191},
abstract = {Endotracheal tubes (ETTs) are a common source of bacterial colonization, leading to ventilator-associated pneumonia (VAP). This research developed a biofilm-resistant ETT, following the principles of green chemistry. Using an aqueous layer-by-layer (LbL) technique, a thick polyelectrolyte multilayered film was deposited on a ventilation tube. The polyelectrolyte multilayered film accommodated silver nanoparticles (AgNPs) formed in situ by reducing Ag+ ions with Eucalyptus citriodora leaf extract. The multilayered film coating conformed to the curved surfaces of the ETT. Film thickness and silver content increased exponentially with the number of polyelectrolyte bilayer pairs, and a sufficiently high AgNPs content of 10-30%w/w was obtained at 75 to 125 bilayer films. Adhesion of the Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa was prevented by 99.9 and 99.99%, respectively, without cytotoxic effects against human lung epithelial cells (p < 0.05).},
}
@article {pmid31028534,
year = {2019},
author = {Perez-Tanoira, R and Aarnisalo, A and Haapaniemi, A and Saarinen, R and Kuusela, P and Kinnari, TJ},
title = {Bacterial biofilm in salivary stones.},
journal = {European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00405-019-05445-1},
pmid = {31028534},
issn = {1434-4726},
abstract = {PURPOSE: To assess the susceptibility of salivary stones to bacterial biofilm formation, which may be involved in the development of salivary gland infection, and to investigate a relation between microbiological aspects and patient characteristics.<br><br>METHODS: This prospective study comprises of 54 patients with sialolithiasis attended in Helsinki University Hospital during 2014-2016. A total of 55 salivary stones were removed, and studied for biofilm formation using fluorescence microscopy and sonication. The isolated organisms were quantified and identified using matrix-assisted laser desorption ionization time-of-flight mass spectrometry.<br><br>RESULTS: Biofilm formation was confirmed on the surface of 39 (70.9%) stones. A total of 96 microorganisms were isolated from 45 salivary stones (81.8%). Two or more organisms were isolated in 33 (73.3%) cases. The main isolates were Streptococcus mitis/oralis (n = 27; 28.1%), followed by Streptococcus anginosus (n = 10; 9.6%), Rothia spp. (n = 8; 8.3%), Streptococcus constellatus (n = 7; 7.3%), and Streptococcus gordonii (n = 6; 6.2%). In all patients showing pre-operative (12 cases) or peri-operative (three cases) drainage of pus, the presence of biofilm was detected in microscopy (p = 0.004). Four patients showed post-operative infection, and in three of them (75.0%), the presence of biofilm was detected. Increased number of pus drainage was found among patients with reflux symptoms or use of proton-pump inhibitors.<br><br>CONCLUSIONS: Salivary stones are susceptible to bacterial biofilm formation, which could be related with the development and severity of the inflammation and the refractory nature of the disease. Sonication of salivary gland stones could be a useful method for finding the etiology of the chronic infection.},
}
@article {pmid31027789,
year = {2019},
author = {Ostrov, I and Sela, N and Belausov, E and Steinberg, D and Shemesh, M},
title = {Adaptation of Bacillus species to dairy associated environment facilitates their biofilm forming ability.},
journal = {Food microbiology},
volume = {82},
number = {},
pages = {316-324},
doi = {10.1016/j.fm.2019.02.015},
pmid = {31027789},
issn = {1095-9998},
abstract = {Biofilm-forming Bacillus species are often involved in contamination of dairy products and therefore present a major microbiological challenge in the field of food quality and safety. In this study, we sequenced and analyzed the genomes of milk- and non-milk-derived Bacillus strains, and evaluated their biofilm-formation potential in milk. Unlike non-dairy Bacillus isolates, the dairy-associated Bacillus strains were characterized by formation of robust submerged and air-liquid interface biofilm (pellicle) during growth in milk. Moreover, genome comparison analysis revealed notable differences in putative biofilm-associated determinants between the dairy and non-dairy Bacillus isolates, which correlated with biofilm phenotype. These results suggest that biofilm formation by Bacillus species might represent a presumable adaptation strategy to the dairy environment.},
}
@article {pmid31027768,
year = {2019},
author = {Pang, X and Yuk, HG},
title = {Effects of the colonization sequence of Listeria monocytogenes and Pseudomonas fluorescens on survival of biofilm cells under food-related stresses and transfer to salmon.},
journal = {Food microbiology},
volume = {82},
number = {},
pages = {142-150},
doi = {10.1016/j.fm.2019.02.002},
pmid = {31027768},
issn = {1095-9998},
abstract = {This study evaluated how the colonization sequence of Listeria monocytogenes and Pseudomonas fluorescens affects biofilm formation and biofilm cell response to food-related stress (desiccation or disinfection) as well as the transferability of L. monocytogenes to salmon products. The results showed that the colonization sequence did not affect the population of dual species biofilms. Furthermore, survival number of L. monocytogenes was 0.8 log CFU/cm2 higher when P. fluorescens was the first colonizer during desiccation or disinfectant treatment in comparison with dual-species biofilms with other colonization sequences. A lower transfer rate of L. monocytogenes biofilm cells from dual-species biofilms was observed as compared to single species biofilms. In particular, L. monocytogenes cells detached at a slower rate during transfer to 10 slices of salmon from dual-species biofilms first established by P. fluorescens. Confocal images revealed more exopolysaccharide production in dual-speciesbiofilms first established by P. fluorescens than in biofilms generated via other sequences. These results indicate that preexisting P. fluorescens biofilms on stainless steel can enhance resistance of L. monocytogenes to desiccation and disinfection, although this setup decreased the transfer rate of L. monocytogenes to salmon slices. Thus, this study highlights the risk of L. monocytogenes contamination in pre-formed Pseudomonas biofilms at salmon processing facilities.},
}
@article {pmid31025881,
year = {2019},
author = {Rebrošová, K and Šiler, M and Samek, O and Růžička, F and Bernatová, S and Ježek, J and Zemánek, P and Holá, V},
title = {Identification of ability to form biofilm in Candida parapsilosis and Staphylococcus epidermidis by Raman spectroscopy.},
journal = {Future microbiology},
volume = {},
number = {},
pages = {},
doi = {10.2217/fmb-2018-0297},
pmid = {31025881},
issn = {1746-0921},
abstract = {Aim: Finding rapid, reliable diagnostic methods is a big challenge in clinical microbiology. Raman spectroscopy is an optical method used for multiple applications in scientific fields including microbiology. This work reports its potential in identifying biofilm positive strains of Candida parapsilosis and Staphylococcus epidermidis. Materials &amp; methods: We tested 54 S. epidermidis strains (23 biofilm positive, 31 negative) and 51 C. parapsilosis strains (27 biofilm positive, 24 negative) from colonies on Mueller-Hinton agar plates, using Raman spectroscopy. Results: The accuracy was 98.9% for C. parapsilosis and 96.1% for S. epidermidis. Conclusion: The method showed great potential for identifying biofilm positive bacterial and yeast strains. We suggest that Raman spectroscopy might become a useful aid in clinical diagnostics.},
}
@article {pmid31025575,
year = {2019},
author = {Gazzola, G and Habimana, O and Quinn, L and Casey, E and Murphy, CD},
title = {Population dynamics of a dual Pseudomonas putida-Pseudomonas fluorescens biofilm in a capillary bioreactor.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-9},
doi = {10.1080/08927014.2019.1598397},
pmid = {31025575},
issn = {1029-2454},
abstract = {Most biofilm studies employ single species, yet in nature biofilms exist as mixed cultures, with inevitable effects on growth and development of each species present. To investigate how related species of bacteria interact in biofilms, two Pseudomonas spp., Pseudomonas fluorescens and Pseudomonas putida, were cultured in capillary bioreactors and their growth measured by confocal microscopy and cell counting. When inoculated in pure culture, both bacteria formed healthy biofilms within 72 h with uniform coverage of the surface. However, when the bioreactors were inoculated with both bacteria simultaneously, P. putida was completely dominant after 48 h. Even when the inoculation by P. putida was delayed for 24 h, P. fluorescens was eliminated from the capillary within 48 h. It is proposed that production of the lipopeptide putisolvin by P. putida is the likely reason for the reduction of P. fluorescens. Putisolvin biosynthesis in the dual-species biofilm was confirmed by mass spectrometry.},
}
@article {pmid31024468,
year = {2019},
author = {Abdel-Nour, M and Su, H and Duncan, C and Li, S and Raju, D and Shamoun, F and Valton, M and Ginevra, C and Jarraud, S and Guyard, C and Kerman, K and Terebiznik, MR},
title = {Polymorphisms of a Collagen-Like Adhesin Contributes to Legionella pneumophila Adhesion, Biofilm Formation Capacity and Clinical Prevalence.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {604},
doi = {10.3389/fmicb.2019.00604},
pmid = {31024468},
issn = {1664-302X},
abstract = {Legionellosis is a severe respiratory illness caused by the inhalation of aerosolized water droplets contaminated with the opportunistic pathogen Legionella pneumophila. The ability of L. pneumophila to produce biofilms has been associated with its capacity to colonize and persist in human-made water reservoirs and distribution systems, which are the source of legionellosis outbreaks. Nevertheless, the factors that mediate L. pneumophila biofilm formation are largely unknown. In previous studies we reported that the adhesin Legionella collagen-like protein (Lcl), is required for auto-aggregation, attachment to multiple surfaces and the formation of biofilms. Lcl structure contains three distinguishable regions: An N-terminal region with a predicted signal sequence, a central region containing tandem collagen-like repeats (R-domain) and a C-terminal region (C-domain) with no significant homology to other known proteins. Lcl R-domain encodes tandem repeats of the collagenous tripeptide Gly-Xaa-Yaa (GXY), a motif that is key for the molecular organization of mammalian collagen and mediates the binding of collagenous proteins to different cellular and environmental ligands. Interestingly, Lcl is polymorphic in the number of GXY tandem repeats. In this study, we combined diverse biochemical, genetic, and cellular approaches to determine the role of Lcl domains and GXY repeats polymorphisms on the structural and functional properties of Lcl, as well as on bacterial attachment, aggregation and biofilm formation. Our results indicate that the R-domain is key for assembling Lcl collagenous triple-helices and has a more preponderate role over the C-domain in Lcl adhesin binding properties. We show that Lcl molecules oligomerize to form large supramolecular complexes to which both, R and C-domains are required. Furthermore, we found that the number of GXY tandem repeats encoded in Lcl R-domain correlates positively with the binding capabilities of Lcl and with the attachment and biofilm production capacity of L. pneumophila strains. Accordingly, the number of GXY tandem repeats in Lcl influences the clinical prevalence of L. pneumophila strains. Therefore, the number of Lcl tandem repeats could be considered as a potential predictor for virulence in L. pneumophila isolates.},
}
@article {pmid31023592,
year = {2019},
author = {Król, J and Nawrot, U and Bartoszewicz, M},
title = {Activity of base analogues (5-fluorouracil, 5-flucytosine) against planktonic cells and mature biofilm of Candida yeast. Effect of combination with folinic acid.},
journal = {Journal de mycologie medicale},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.mycmed.2019.04.003},
pmid = {31023592},
issn = {1773-0449},
abstract = {BACKGROUND: The increasing number of Candida infections, especially those caused by non-C. albicans species and resistant strains, is a serious medical problem.<br><br>OBJECTIVES: In this study, the antifungal activity of base analogues, 5-flucytosine (5-FC) and 5-fluorouracil (5-FU), was tested against planktonic cells as well as against mature biofilm.<br><br>METHODS: Tests were performed according the EUCAST methodology. Antibiofilm effectiveness of tested drugs was determined by the crystal violet staining method. The cytotoxicity assays was performed according to the ISO 10993-5 norm.<br><br>RESULTS: 5-FC and 5-FU were effective against fifteen fluconazole resistant Candida glabrata strains with an average minimal inhibitory concentration (MIC) of 0.152mg/L and 0.39mg/L, respectively. Folinic acid (folinate- e.g., leucovorin) is a common drug used in oncology simultaneously with 5-FU. In our tests folinate was able to lower MIC for 5-FC from 0.152 to 0.058mg/L (P<0.05). In the biofilm assay 5-FU and 5-FC alone did not induce any changes in the biomass of mature biofilm. Addition of folinate to each base analogue resulted in up to 90% reduction of biomass. Viability tests show that a concentration of 64mg/L of 5-FC and 5-FU supplemented with folinate can be fungicidal against mature biofilms of some Candida isolates. No cytotoxic effect was found for combination of FOL and 5-FC.<br><br>CONCLUSION: Therapy of 5-FU+folinate is well known in cancer treatment, in this study we reveal the beneficial effect of folinate on antifungal activity of 5-FC as well as the antifungal potential of 5-FU+folinate.},
}
@article {pmid31022836,
year = {2019},
author = {Flockton, TR and Schnorbus, L and Araujo, A and Adams, J and Hammel, M and Perez, LJ},
title = {Inhibition of Pseudomonas aeruginosa Biofilm Formation with Surface Modified Polymeric Nanoparticles.},
journal = {Pathogens (Basel, Switzerland)},
volume = {8},
number = {2},
pages = {},
doi = {10.3390/pathogens8020055},
pmid = {31022836},
issn = {2076-0817},
abstract = {The gram-negative bacterial pathogen Pseudomonas aeruginosa represents a prominent clinical concern. Due to the observed high levels of antibiotic resistance, copious biofilm formation, and wide array of virulence factors produced by these bacteria, new treatment technologies are required. Here, we present the development of a series of P. aeruginosa LecA-targeted polymeric nanoparticles and demonstrate the anti-adhesion and biofilm inhibitory properties of these constructs.},
}
@article {pmid31022421,
year = {2019},
author = {Maktabi, H and Ibrahim, M and Alkhubaizi, Q and Weir, M and Xu, H and Strassler, H and Fugolin, APP and Pfeifer, CS and Melo, MAS},
title = {Underperforming light curing procedures trigger detrimental irradiance-dependent biofilm response on incrementally placed dental composites.},
journal = {Journal of dentistry},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jdent.2019.04.003},
pmid = {31022421},
issn = {1879-176X},
abstract = {OBJECTIVES: Insufficient radiant exposure (J/cm2) may provide an early trigger in a cascade of detrimental responses on incrementally-place composite, especially the bottom layer. This study aimed to assess the influence of poor radiant exposure, the degree of conversion (%DC), water sorption/ solubility and S. mutans biofilm formation on conventional, incrementally placed composites and to establish a relationship between these factors.<br><br>METHODS: Two light units operating at 600 and 1,000 mW/cm2 and four most common operator-dependent curing conditions had the radiant exposure (RE) recorded. All the specimens were subjected to S. mutans biofilm model for 14 days. The %DC, biofilm formation expressed by colony-forming units (CFU), water sorption/ solubility and surface roughness/ SEM were assessed. Data were submitted to two-way ANOVA and Tukey post-hoc test (α = 0.05). Pearson correlation was also determined.<br><br>RESULTS: The influence of RE on S. mutans CFU values and DC are dependent on the curing conditions and irradiance (p < 0.05). A negative relationship was observed between RE and biofilm formation. The operator-dependent curing conditions have shown RE reduction varying from 49.4% to 73.5% in relation to control. The difference in DC between top/bottom of cylinder varied from 13% to 21% for 1,000 mW/cm2and from 29% to 53% for LCU600. The roughness, solubility and salivary sorption were greater for low RE.<br><br>CONCLUSION: Poor, deficient curing procedures provide an early trigger in a negative pathway of events for incrementally-place dental composite including a biological response by increased biofilm formation by S. mutans, a relevant factor for secondary caries development.<br><br>SIGNIFICANCE: The susceptibility to variation in the outcomes was RE -dependent. The optimization of the curing procedures ensures the maximum performance in the chain of events involved in the light curing process of resin-based materials and potentially reduce the risk factors of secondary caries development.},
}
@article {pmid31021431,
year = {2019},
author = {Barron, CL and Kamel-Abusalha, LB and Sethia, R and Goodman, SD and Elmaraghy, CA and Bakaletz, LO},
title = {Identification of essential biofilm proteins in middle ear fluids of otitis media with effusion patients.},
journal = {The Laryngoscope},
volume = {},
number = {},
pages = {},
doi = {10.1002/lary.28011},
pmid = {31021431},
issn = {1531-4995},
support = {R01 DC011818//National Institutes of Health/ National Institute on Deafness and Other Communication Disorders/ ; },
abstract = {OBJECTIVES: Otitis media with effusion (OME) is a common disease of childhood that is largely asymptomatic. However, middle ear fluid can persist for months and negatively impact a child's quality of life. Many cases of OME remain chronic and require surgical intervention. Because biofilms are known to contribute to the persistence of many diseases, this study examined effusions collected from children with chronic OME for the presence of essential biofilm structural components, members of the DNABII family of bacterial DNA-binding proteins.<br><br>METHODS: Middle ear effusions were recovered from 38 children with chronic OME at the time of tympanostomy tube insertion. A portion of each specimen was submitted for microbiology culture. The remaining material was assessed by immunoblot to quantitate individual DNABII proteins, integration host factor (IHF), and histone-like protein (HU).<br><br>RESULTS: Sixty-five percent of effusions (24 of 37) were culture-positive for bacterial species or yeast, whereas 35% (13 of 37) were culture-negative. IHF was detected in 95% (36 of 38) at concentrations from 2 to 481 ng/μL effusion. HU was detected in 95% (36 of 38) and quantitated from 13 to 5,264 ng/μL effusion (P ≤ 0.05 compared to IHF).<br><br>CONCLUSION: Because DNABII proteins are essential structural components of bacterial biofilms, these data lend further support to our understanding that biofilms are present in the vast majority of chronic middle ear effusions, despite negative culture results. The presence and ubiquity of DNABII proteins in OME specimens indicated that these proteins can serve as an important clinical target for our novel DNABII-directed strategy to treat biofilm diseases such as chronic OME.<br><br>LEVEL OF EVIDENCE: NA Laryngoscope, 2019.},
}
@article {pmid31021332,
year = {2019},
author = {Gómez-Gómez, B and Arregui, L and Serrano, S and Santos, A and Pérez-Corona, T and Madrid, Y},
title = {Selenium and tellurium-based nanoparticles as interfering factors in quorum sensing-regulated processes: violacein production and bacterial biofilm formation.},
journal = {Metallomics : integrated biometal science},
volume = {},
number = {},
pages = {},
doi = {10.1039/c9mt00044e},
pmid = {31021332},
issn = {1756-591X},
abstract = {A cell-to-cell communication system called quorum sensing (QS) promotes the transcription of certain target genes in bacterial cells leading to the activation of different cellular processes, some of them related to bacterial biofilm formation. The formation of bacterial biofilms favours antibiotic resistance, which is nowadays a significant public-health problem. In this study, the effect of selenium (SeNPs) and tellurium (TeNPs) nanoparticles was examined in two bacterial processes mediated by QS: violacein production by Chromobacterium violaceum and biofilm formation by Pseudomonas aeruginosa. For this purpose, quantification of the pigment production in the presence of these nanoparticles was monitored using the C. violaceum strain. Additionally, a combination of different microscopical imaging techniques was applied to examine the changes in the 3D biofilm structure of P. aeruginosa, which were quantified through performing architectural metric calculations (substratum area, cell area coverage and biovolume). SeNPs produce an 80% inhibition in the violacein production by C. violaceum and a significant effect on the P. aeruginosa biofilm architecture (a reduction of 80% in the biovolume of the bacterial biofilm was obtained). TeNPs similarly affect violacein production and the P. aeruginosa biofilm structure but at lower concentration levels. The results obtained suggest an important disruption of the QS signalling system by SeNPs and TeNPs, supporting nanotechnology as a promising tool to fight against the emerging problem of bacterial resistance related to bacterial biofilm formation.},
}
@article {pmid31021282,
year = {2019},
author = {Yang, Y and Hwang, EH and Park, BI and Choi, NY and Kim, KJ and You, YO},
title = {Artemisia princeps Inhibits Growth, Biofilm Formation, and Virulence Factor Expression of Streptococcus mutans.},
journal = {Journal of medicinal food},
volume = {},
number = {},
pages = {},
doi = {10.1089/jmf.2018.4304},
pmid = {31021282},
issn = {1557-7600},
abstract = {This study was designed to determine whether the ethanol extract of Artemisia princeps could inhibit the cariogenic activity of Streptococcus mutans. The increase in acid production and biofilm formation by S. mutans were evaluated. The expression levels of virulence factor genes were determined by performing the real-time polymerase chain reaction (PCR). The bactericidal effect was tested by confocal laser scanning microscopy. The A. princeps extract was observed to inhibit the growth of S. mutans at concentrations >0.05 mg/mL (P < .05). After using the safranin staining method, we found that the A. princeps extract had an inhibitory effect against biofilm formation at a concentration of >0.05 mg/mL. These experimental results were similar to that observed with the scanning electron microscopy. The results of the confocal microscopy revealed that the A. princeps extract at high concentrations of 0.4-3.2 mg/mL showed a bactericidal effect in a concentration-dependent manner. According to the results of the real-time PCR analysis, it was observed that the A. princeps extract inhibited the expression of virulence factor genes. These results suggest that A. princeps may inhibit the cariogenic activity of S. mutans, and may be useful as an anticariogenic agent.},
}
@article {pmid31020511,
year = {2019},
author = {Li, X and Zhang, X and Zhao, X and Yu, B and Weng, L and Li, Y},
title = {Efficient Removal of Metolachlor and Bacterial Community of Biofilm in Bioelectrochemical Reactors.},
journal = {Applied biochemistry and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12010-019-03014-0},
pmid = {31020511},
issn = {1559-0291},
support = {2017YFD0800704//National Key R&amp;D Program of China/ ; 41601536 and 31500425//National Natural Science Foundation of China/ ; 16JCQNJC08800//Natural Science Foundation of Tianjin city of China/ ; 2017-05//Opening Foundation of Ministry of Education of China Key Laboratory of Pollution Processes and Environmental Criteria/ ; 2017-2018//Central Public-interest Scientific Institution Basal Research Fund/ ; },
abstract = {The microbial fuel cell (MFC) provides an inexhaustible electron acceptor to generate current and enhance the degradation of organic compounds. In MFCs with metolachlor as the sole carbon source, the degradation efficiency accelerated by 98%, with 61-76% of enhancement for the degradates, ethane sulfonic acid and oxanilic acid, respectively. According to quantifying primary metabolites of deschloro and metolachlor-2-hydroxyas, dechlorination and alcoholization were deemed as antecedent steps of metolachlor bioelectrochemical degradation. The energy recovery was infeasible by sole addition of metolachlor (at 13 ± 4 °C from equivalent weight of 0.224 mg). In MFCs with metolachlor and sodium acetate as the concomitant carbon sources, the electricity generation recovered to a level comparable to the controls, instead of increasing the removal efficiency of metolachlor. These results suggest that a low-efficiently direct electron transfer occurred between electricigens and metolachlor degraders. The Illumina sequencing showed that species of Paracoccus and Aquamicrobium played a potential degradation effect, while Comamonas sp. replaced Geobacter sp. as the predominant electricigen after addition of metolachlor. This study demonstrates that MFCs could be used as a promising alternative for treatment of chloroacetanilide herbicide contaminated wastewaters by means of a rapidly established active bacterial community. Graphical Abstract .},
}
@article {pmid31020467,
year = {2019},
author = {Özcan, SS and Dieser, M and Parker, AE and Balasubramanian, N and Foreman, CM},
title = {Quorum sensing inhibition as a promising method to control biofilm growth in metalworking fluids.},
journal = {Journal of industrial microbiology &amp; biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10295-019-02181-7},
pmid = {31020467},
issn = {1476-5535},
support = {1635347//Directorate for Engineering/ ; P20GM103474//Foundation for the National Institutes of Health/ ; },
abstract = {Microbial contamination in metalworking systems is a critical problem. This study determined the microbial communities in metalworking fluids (MWFs) from two machining shops and investigated the effect of quorum sensing inhibition (QSI) on biofilm growth. In both operations, biofilm-associated and planktonic microbial communities were dominated by Pseudomonadales (60.2-99.7%). Rapid recolonization was observed even after dumping spent MWFs and meticulous cleaning. Using Pseudomonas aeruginosa PAO1 as a model biofilm organism, patulin (40 µM) and furanone C-30 (75 µM) were identified as effective QSI agents. Both agents had a substantially higher efficacy compared to α-amylase (extracellular polymeric substance degrading enzyme) and reduced biofilm formation by 63% and 76%, respectively, in MWF when compared to untreated controls. Reduced production of putatively identified homoserine lactones and quinoline in MWF treated with QS inhibitors support the effect of QSI on biofilm formation. The results highlight the effectiveness of QSI as a potential strategy to eradicate biofilms in MWFs.},
}
@article {pmid31019496,
year = {2019},
author = {Singh, AK and Yadav, S and Chauhan, BS and Nandy, N and Singh, R and Neogi, K and Roy, JK and Srikrishna, S and Singh, RK and Prakash, P},
title = {Classification of Clinical Isolates of Klebsiella pneumoniae Based on Their in vitro Biofilm Forming Capabilities and Elucidation of the Biofilm Matrix Chemistry With Special Reference to the Protein Content.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {669},
doi = {10.3389/fmicb.2019.00669},
pmid = {31019496},
issn = {1664-302X},
abstract = {Klebsiella pneumoniae is a human pathogen, capable of forming biofilms on abiotic and biotic surfaces. The limitations of the therapeutic options against Klebsiella pneumoniae is actually due to its innate capabilities to form biofilm and harboring determinants of multidrug resistance. We utilized a newer approach for classification of biofilm producing Klebsiella pneumoniae isolates and subsequently we evaluated the chemistry of its slime, more accurately its biofilm. We extracted and determined the amount of polysaccharides and proteins from representative bacterial biofilms. The spatial distribution of sugars and proteins were then investigated in the biofilm matrix using confocal laser scanning microscopy (CLSM). Thereafter, the extracted matrix components were subjected to sophisticated analysis incorporating Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, one-dimensional gel-based electrophoresis (SDS-PAGE), high performance liquid chromatography (HPLC), and MALDI MS/MS analysis. Besides, the quantification of its total proteins, total sugars, uronates, total acetyl content was also done. Results suggest sugars are not the only/major constituent of its biofilms. The proteins were harvested and subjected to SDS-PAGE which revealed various common and unique protein bands. The common band was excised and analyzed by HPLC. MALDI MS/MS results of this common protein band indicated the presence of different proteins within the biofilm. The 55 different proteins were identified including both cytosolic and membrane proteins. About 22 proteins were related to protein synthesis and processing while 15 proteins were identified related to virulence. Similarly, proteins related to energy and metabolism were 8 and those related to capsule and cell wall synthesis were 4. These results will improve our understanding of Klebsiella biofilm composition and will further help us design better strategies for controlling its biofilm such as techniques focused on weakening/targeting certain portions of the slime which is the most common building block of the biofilm matrix.},
}
@article {pmid31019240,
year = {2019},
author = {Prateeksha, and Barik, SK and Singh, BN},
title = {Nanoemulsion-loaded hydrogel coatings for inhibition of bacterial virulence and biofilm formation on solid surfaces.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {6520},
doi = {10.1038/s41598-019-43016-w},
pmid = {31019240},
issn = {2045-2322},
abstract = {The indiscriminate use of antibiotics has led to the emergence of drug-resistant bacteria which has become one of the biggest challenges of the twenty-first century for the researchers to combat and in turn search for novel targets which could lead to the development of effective and sustainable therapies. Inhibition of biofilm formation and virulence of bacterial pathogens is an emerging approach to address the challenges related to bacterial infections. To suppress the virulence and biofilm formation by Escherichia coli O157:H7 (ECOH), we developed stable nanoemulsion (NE) of Gaultheria fragrantissima Wall. essential oil's (EO) bioactive compounds, viz., eugenol (E-NE) and methyl salicylate (MS-NE) that showed significantly higher anti-biofilm and anti-virulence activities as compared to eugenol and methyl salicylate without affecting ECOH planktonic cell growth. Transcriptional analysis showed that E-NE and MS-NE reduced the expression of genes, including curli, type I fimbriae, Shiga-like toxins, quorum sensing, and ler-controlled toxins, which are needed for biofilm formation, pathogenicity, and attachment. E-NE and MS-NE loaded hydrogel coatings showed superior anti-biofilm activity against ECOH on glass, plastic and meat surfaces as compared to eugenol and methyl salicylate loaded coatings. Conclusively, NE-loaded hydrogel coatings could be used in combating ECOH infection on solid surfaces through anti-biofilm and anti-virulence strategies.},
}
@article {pmid31017520,
year = {2019},
author = {Pandey, S and Sarkar, S},
title = {Spatial distribution of major bacterial species and different volatile fatty acids in a two-phase anaerobic biofilm reactor with PVA gel beads as bio-carrier.},
journal = {Preparative biochemistry &amp; biotechnology},
volume = {},
number = {},
pages = {1-14},
doi = {10.1080/10826068.2019.1605525},
pmid = {31017520},
issn = {1532-2297},
abstract = {Conventional completely mixed anaerobic treatment systems limit the chances of the different species of bacteria to spatially group together according to their mutual cooperation and as a result, show a lower efficiency and vulnerability towards shock situations. It is interesting to know about the stratification of the different bacterial species participating in the degradation process and the intermediates that they produce. In this study, we established and optimized a two-phase anaerobic packed bed biofilm reactor system (AnPBR) with porous PVA gel beads used as bio-carriers and ran the reactor system in a steady state to observe the VFAs produced along with the microbial diversity of the predominant species at different stages of the reactor system. We observed that acetate and butyrate were the predominant intermediate VFAs while concentrations of other VFAs such that propionic acid were low. Acetobacterium and Clostridium were found to be the most abundant bacterial species in acidogenic reactor while methanogenic reactor was highly enriched with Methanobacterium and Methanosarcina. Apart from the above, syntrophic populations such as Syntrophobactor wolinii were also observed to be dominant in both the reactors - especially towards the end of acidogenic reactor and the initial part of the methanogenic reactor.},
}
@article {pmid31015909,
year = {2019},
author = {Nguyen, TV and Peszko, MT and Melander, RJ and Melander, C},
title = {Using 2-aminobenzimidazole derivatives to inhibit Mycobacterium smegmatis biofilm formation.},
journal = {MedChemComm},
volume = {10},
number = {3},
pages = {456-459},
doi = {10.1039/c9md00025a},
pmid = {31015909},
issn = {2040-2511},
abstract = {Biofilm formation by mycobacteria can lead to enhanced antibiotic tolerance. Herein, we report on the identification of a series of 2-aminobenzimidazole (2-ABI) derivatives that potently inhibit biofilm formation by Mycobacterium smegmatis.},
}
@article {pmid31015652,
year = {2019},
author = {Tavares, ER and Gionco, B and Morguette, AEB and Andriani, GM and Morey, AT and do Carmo, AO and de Pádua Pereira, U and Andrade, G and de Oliveira, AG and Pinge-Filho, P and Nakamura, CV and Yamauchi, LM and Yamada-Ogatta, SF},
title = {Phenotypic characteristics and transcriptome profile of Cryptococcus gattii biofilm.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {6438},
doi = {10.1038/s41598-019-42896-2},
pmid = {31015652},
issn = {2045-2322},
abstract = {In this study, we characterized Cryptococcus gattii biofilm formation in vitro. There was an increase in the density of metabolically active sessile cells up to 72 h of biofilm formation on polystyrene and glass surfaces. Scanning electron microscopy and confocal laser scanning microscopy analysis revealed that in the early stage of biofilm formation, yeast cells adhered to the abiotic surface as a monolayer. After 12 h, extracellular fibrils were observed projecting from C. gattii cells, connecting the yeast cells to each other and to the abiotic surface; mature biofilm consisted of a dense network of cells deeply encased in an extracellular polymeric matrix. These features were also observed in biofilms formed on polyvinyl chloride and silicone catheter surfaces. We used RNA-Seq-based transcriptome analysis to identify changes in gene expression associated with C. gattii biofilm at 48 h compared to the free-floating planktonic cells. Differential expression analysis showed that 97 and 224 transcripts were up-regulated and down-regulated in biofilm, respectively. Among the biological processes, the highest enriched term showed that the transcripts were associated with cellular metabolic processes, macromolecule biosynthetic processes and translation.},
}
@article {pmid31015181,
year = {2019},
author = {Ding, X and Wei, D and Guo, W and Wang, B and Meng, Z and Feng, R and Du, B and Wei, Q},
title = {Biological denitrification in an anoxic sequencing batch biofilm reactor: Performance evaluation, nitrous oxide emission and microbial community.},
journal = {Bioresource technology},
volume = {285},
number = {},
pages = {121359},
doi = {10.1016/j.biortech.2019.121359},
pmid = {31015181},
issn = {1873-2976},
abstract = {The present study evaluated the performance of biological denitrification in an anoxic sequencing batch biofilm reactor (ASBBR) and its nitrous oxide (N2O) emission. After 90 days operation, the effluent chemical oxygen demand and total nitrogen removal efficiencies high of 94.8% and 95.0%, respectively. Both polysaccharides and protein contents were reduced in bound EPS (TB-EPS) and loosely bound EPS (LB-EPS) after biofilm formation. According to typical cycle, N2O release rate was related to the free nitrous acid (FNA) concentration with the maximum value of 3.88 μg/min and total conversion rate of 1.27%. Two components were identified from EEM-PARAFAC model in soluble microbial products (SMP). Protein-like substances for component 1 changed significantly in denitrification process, whereas humic-like and fulvic acid-like substances for component 2 remained relatively stable. High-throughput sequencing results showed that Lysobacter, Tolumonas and Thauera were the dominant genera, indicating the co-existence of autotrophic and heterotrophic denitrifiers in ASBBR.},
}
@article {pmid31014001,
year = {2019},
author = {Brust, FR and Boff, L and da Silva Trentin, D and Pedrotti Rozales, F and Barth, AL and Macedo, AJ},
title = {Macrocolony of NDM-1 Producing Enterobacterhormaechei subsp. oharae Generates Subpopulations with Different Features Regarding the Response of Antimicrobial Agents and Biofilm Formation.},
journal = {Pathogens (Basel, Switzerland)},
volume = {8},
number = {2},
pages = {},
doi = {10.3390/pathogens8020049},
pmid = {31014001},
issn = {2076-0817},
support = {1871-25511/13-4//Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul/ ; 408578/2013-0//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; 443150/2014-1//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; doctoral fellowship//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; 465718/2014-0//Instituto Nacional de Ciência e Tecnologia/ ; },
abstract = {Enterobacter cloacae complex has been increasingly recognized as a nosocomial pathogen representing the third major Enterobacteriaceae species involved with infections. This study aims to evaluate virulence and antimicrobial susceptibility of subpopulations generated from macrocolonies of NDM-1 producing Enterobacter hormaechei clinical isolates. Biofilm was quantified using crystal violet method and fimbrial genes were investigated by PCR. Susceptibility of antimicrobials, alone and combined, was determined by minimum inhibitory concentration and checkerboard assays, respectively. Virulence and efficacy of antimicrobials were evaluated in Galleria mellonella larvae. Importantly, we verified that some subpopulations that originate from the same macrocolony present different biofilm production ability and distinct susceptibility to meropenem due to the loss of blaNDM-1 encoding plasmid. A more in-depth study was performed with the 798 macrocolony subpopulations. Type 3 fimbriae were straightly related with biofilm production; however, virulence in larvae was not statistically different among subpopulations. Triple combination with meropenem-rifampicin-polymyxin B showed in vitro synergistic effect against all subpopulations; while in vivo this treatment showed different efficacy rates for 798-1S and 798-4S subpopulations. The ability of multidrug resistant E. hormaechei isolates in generating bacterial subpopulations presenting different susceptible and virulence mechanisms are worrisome and may explain why these infections are hardly overcome.},
}
@article {pmid31013388,
year = {2019},
author = {Chevalier, M and Doglio, A and Rajendran, R and Ramage, G and Prêcheur, I and Ranque, S},
title = {Inhibition of adhesion-specific genes by Solidago virgaurea extract causes loss of Candida albicans biofilm integrity.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14289},
pmid = {31013388},
issn = {1365-2672},
abstract = {AIMS: Candida albicans biofilms are commonly associated to severe oral infections. We previously discovered that a crude extract from the Solidago virgaurea plant (SV-extract) was a potent inhibitor of C. albicans biofilm formation. Here, we further investigate the mechanisms underlying C. albicans biofilm inhibition by the SV-extract.<br><br>METHODS AND RESULTS: The SV-extract was shown to inhibit laboratory and clinical C. albicans isolates adherence and hyphal transition on inert support and epithelial human cells, without affecting viability and growth of planktonic yeasts. Interestingly, RT-PCR-based experiments demonstrated that some key genes involved in adhesion and hyphal morphological switch (e.g. Hwp1p, Ece1p, Als3p) were strongly down-regulated by the SV-extract. Moreover, antimicrobial synergy testing (checkerboard assay) demonstrated that antifungal effects of miconazole, nystatin or a common antiseptic mouthwash were synergistically improved when used in combination with the SV extract.<br><br>CONCLUSIONS: The SV-extract prevents C. albicans biofilm formation through direct inhibition of key adherence and hyphae-associated genes.<br><br>Biofilm is considered as a key virulence factor of C. albicans infection. Our discovery of an inhibitor specifically acting on genes involved in biofilm formation paves the way for the future development of a new class of antifungal product. This article is protected by copyright. All rights reserved.},
}
@article {pmid31013054,
year = {2019},
author = {Haolan, Z and Wang, D and Zuo, X and Gao, C},
title = {UV-responsive multilayers with multiple functions for biofilm destruction and tissue regeneration.},
journal = {ACS applied materials &amp; interfaces},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsami.9b04428},
pmid = {31013054},
issn = {1944-8252},
abstract = {The increasing demands of surgical implantation highlight the significance of anti-infection of medical devices, especially antibiofilm contamination on the surface of implants. The biofilms developed by colonized microbes will largely hinder the adhesion of host cells, leading to the failure in long term applications. In this work, UV-responsive multilayers were fabricated by stepwise assembly of poly(pyrenemethyl acrylate-co-acrylic acid) (P(PA-co-AA)) micelles and chitosan on different types of substrates. Under UV irradiation, the cleavage of pyrene ester bonds in the P(PA-co-AA) molecules resulted in the increase of roughness and hydrophilicity of the multilayers. During this process reactive oxygen species (ROS) were generated in situ within 10 s, which destroyed the biofilms of Staphylococcus aureus (S. aureus), leading to the degradation of bacterial matrix. The antibacterial rate was above 99.999%. The UV-irradiated multilayers allowed the attachment and proliferation of fibroblasts, endothelial cells and smooth muscle cells, benefiting the tissue integration of the implants. When polydimethylsiloxane (PDMS) slices with the multilayers were implanted in vivo and irradiated by UV, the density of bacteria and inflammatory level (judging from the number of neutrophils) decreased significantly. Moreover, formation of neo blood vessels surrounding the implants was observed after implantation for 7 d. These results reveal that the photo-responsive multilayers endow the implants with multifunctions of simultaneous anti-biofilm and tissue integration, shedding a light for applications in surface modification of implants in particular for long term use.},
}
@article {pmid31011774,
year = {2019},
author = {Liu, J and Li, W and Zhu, X and Zhao, H and Lu, Y and Zhang, C and Lu, Z},
title = {Surfactin effectively inhibits Staphylococcus aureus adhesion and biofilm formation on surfaces.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-019-09808-w},
pmid = {31011774},
issn = {1432-0614},
support = {31571887//National Natural Science Foundation of China/ ; CX 16-1058//Jiangsu Agricultural Science and Technology Innovation Fund/ ; },
abstract = {Biosurfactants are amphiphilic compounds that composed of hydrophilic and hydrophobic moieties, which possess the ability of self-organizing between phases, reducing the interfacial tension, and forming aggregates such as micelles. This spontaneous process results in significant changes in surface properties that directly influence the adherence of microorganisms. In this study, the ability of surfactin, a biosurfactant produced by Bacillus subtilis in reducing adhesion and disrupting the presence of biofilm of Staphylococcus aureus (S. aureus) on several surfaces, was investigated. Significant biofilm removal was observed on glass, polystyrene, and stainless steel surfaces. Furthermore, we explored the probable mechanism about how surfactin affected S. aureus biofilm formation. Based on our findings, surfactin had a significant effect on the polysaccharides production and especially decreased the percentage of alkali-soluble polysaccharide in biofilms. It also down-regulated the expression of icaA and icaD significantly, which are necessary for the important constituents to take shape of staphylococcal biofilm. In addition, it was found that the lipopeptide affected the quorum sensing (QS) system in S. aureus through regulating the auto inducer 2 (AI-2) activity, which has been reported to be negative for biofilm formation in S. aureus. These above properties could be applied in developing surfactin as a potential pre-coating agent on material surfaces to prevent S. aureus biofilm formation.},
}
@article {pmid31010902,
year = {2019},
author = {Cassin, EK and Tseng, BS},
title = {Pushing beyond the envelope: the potential roles of OprF in Pseudomonas aeruginosa biofilm formation and pathogenicity.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00050-19},
pmid = {31010902},
issn = {1098-5530},
abstract = {The ability of Pseudomonas aeruginosa to form biofilms, which are communities of cells encased in a self-produced extracellular matrix, protects the cells from antibiotics and the host immune response. While some biofilm matrix components, such as exopolysaccharides and extracellular DNA, are relatively well characterized, the extracellular matrix proteins remain understudied. Multiple proteomic analyses of the P. aeruginosa soluble biofilm matrix and outer membrane vesicles, which are a component of the matrix, have identified OprF as an abundant matrix protein. To date, the few reports on the effects of oprF mutations on biofilm formation are conflicting, and little is known about the potential role of OprF in the biofilm matrix. The majority of OprF studies focus on the protein as a cell-associated porin. As a component of the outer membrane, OprF assumes dual conformations and is involved in solute transport, as well as cell envelope integrity. Here we review the current literature on OprF in P. aeruginosa, discussing how the structure and function of the cell-associated and matrix-associated protein may affect biofilm formation and pathogenesis in order to inform future research on this understudied matrix protein.},
}
@article {pmid31010859,
year = {2019},
author = {Hunt-Serracin, AC and Parks, BJ and Boll, J and Boutte, C},
title = {Biofilm-associated Mycobacterium abscessus cells have altered antibiotic tolerance and surface glycolipids in Artificial Cystic Fibrosis Sputum Media.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.02488-18},
pmid = {31010859},
issn = {1098-6596},
abstract = {Mycobacterium abscessus (Mab) is a biofilm-forming, multi-drug resistant, non-tuberculous mycobacterial (NTM) pathogen increasingly found in Cystic Fibrosis patients. Antibiotic treatment for these infections is often unsuccessful, partly due to Mab's high intrinsic antibiotic resistance. It is not clear whether antibiotic tolerance caused by biofilm formation also contributes to poor treatment outcomes. We studied the surface glycolipids and antibiotic tolerance of Mab biofilms grown in Artificial Cystic Fibrosis Sputum (ACFS) media in order to determine how they are affected by nutrient conditions that mimic infection. We found that Mab displays more of the virulence lipid trehalose dimycolate when grown in ACFS compared to standard lab media. In ACFS media, biofilm-associated cells are more antibiotic tolerant than planktonic cells in the same well. This contrasts with standard lab medias, where biofilm and planktonic cells are both highly antibiotic tolerant. These results indicate that Mab cell physiology in biofilms depends on environmental factors, and that nutrient conditions found within Cystic Fibrosis infections could contribute to both increased virulence and antibiotic tolerance.},
}
@article {pmid31010041,
year = {2019},
author = {Ostrov, I and Paz, T and Shemesh, M},
title = {Robust Biofilm-Forming Bacillus Isolates from the Dairy Environment Demonstrate an Enhanced Resistance to Cleaning-in-Place Procedures.},
journal = {Foods (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/foods8040134},
pmid = {31010041},
issn = {2304-8158},
support = {4210343//Israeli Dairy Board/ ; },
abstract = {One of the main strategies for maintaining the optimal hygiene level in dairy processing facilities is regular cleaning and disinfection, which is incorporated in the cleaning-in-place (CIP) regimes. However, a frail point of the CIP procedures is their variable efficiency in eliminating biofilm bacteria. In the present study, we evaluated the susceptibility of strong biofilm-forming dairy Bacillus isolates to industrial cleaning procedures using two differently designed model systems. According to our results, the dairy-associated Bacillus isolates demonstrate a higher resistance to CIP procedures, compared to the non-dairy strain of B. subtilis. Notably, the tested dairy isolates are highly persistent to different parameters of the CIP operations, including the turbulent flow of liquid (up to 1 log), as well as the cleaning and disinfecting effects of commercial detergents (up to 2.3 log). Moreover, our observations indicate an enhanced resistance of poly-γ-glutamic acid (PGA)-overproducing B. subtilis, which produces high amounts of proteinaceous extracellular matrix, to the CIP procedures (about 0.7 log, compared to the wild-type non-dairy strain of B. subtilis). We therefore suggest that the enhanced resistance to the CIP procedures by the dairy Bacillus isolates can be attributed to robust biofilm formation. In addition, this study underlines the importance of evaluating the efficiency of commercial cleaning agents in relation to strong biofilm-forming bacteria, which are relevant to industrial conditions. Consequently, we believe that the findings of this study can facilitate the assessment and refining of the industrial CIP procedures.},
}
@article {pmid31007867,
year = {2019},
author = {Zhang, Y and Shi, W and Song, Y and Wang, J},
title = {Metatranscriptomic analysis of an in vitro biofilm model reveals strain-specific interactions among multiple bacterial species.},
journal = {Journal of oral microbiology},
volume = {11},
number = {1},
pages = {1599670},
doi = {10.1080/20002297.2019.1599670},
pmid = {31007867},
issn = {2000-2297},
abstract = {Interactions among bacteria can affect biofilm properties. Method: Here, we investigated the role of different bacteria in functional dysbiosis of an in vitro polymicrobial subgingival plaque model using both 16S rRNA and metatranscriptomic sequencing. Results: We found that high-virulence Porphyromonas gingivalis W83 had greater effects on the symbiotic species than the low-virulence P. gingivalis ATCC33277, and that Prevotella intermedia exacerbated the effects of W83. P. gingivalis significantly influenced the expression of genes related to metabolic pathways and quorum sensing of commensal oral species in a strain-specific manner. P. intermedia exerted synergistic effects with P. gingivalis W83 but antagonistic effects with strain ATCC33277, which may regulate the expression of virulence factors of P. gingivalis through the clp regulator. Discussion: The interaction networks indicated that the strongest correlation was between Fusobacterium nucleatum and Streptococcus mitis, which demonstrated their bridge and cornerstone roles in biofilm. Changes in the expression of genes relating to outer membrane proteins in F. nucleatum indicated that the addition of different bacteria can interfere with the co-adherence among F. nucleatum and other partners. Conclusion: We report here the existence of strain-specific interactions in subgingival plaque, which may enhance our understanding of periodontal micro-ecology and facilitate the development of improved plaque control strategies.},
}
@article {pmid31006400,
year = {2019},
author = {da Silva Carvalho, T and Rodrigues Perez, LR},
title = {Impact of biofilm production on polymyxin B susceptibility among Pseudomonas aeruginosa clinical isolates.},
journal = {Infection control and hospital epidemiology},
volume = {},
number = {},
pages = {1-2},
doi = {10.1017/ice.2019.85},
pmid = {31006400},
issn = {1559-6834},
}
@article {pmid31006166,
year = {2019},
author = {Reynoso, E and Ferreyra, DD and Durantini, EN and Spesia, MB},
title = {Photodynamic inactivation to prevent and disrupt Staphylococcus aureus biofilm under different media conditions.},
journal = {Photodermatology, photoimmunology &amp; photomedicine},
volume = {},
number = {},
pages = {},
doi = {10.1111/phpp.12477},
pmid = {31006166},
issn = {1600-0781},
abstract = {OBJECTIVE: The goal of this work was investigate the photodynamic activity of 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl]chlorin (TAPC) and zinc(II) 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]phthalocyanine iodide (ZnPPc4+) as photosensitizers to inactivate S. aureus biofilms and prevent their formations in different culture media.<br><br>METHODS: We incubated S. aureus biofilms in different culture media: tryptic soy (TS), nutrient (N), Müeller Hinton (MH) broth, TS with glucose 2 and 5% (w/v) with 5 μM ZnPPc4+ or TAPC and irradiated with visible light (350-800 nm). Photodynamic inactivation (PDI) was determined by count of colony forming units (CFU) and crystal violet method. Furthermore, we studied PDI effect on biofilm development in TS broth. Finally, we examined the effects of PDI on the structure of S. aureus biofilm.<br><br>RESULTS: Greater inactivation was achieved, using TAPC or ZnPPc4+ , when S. aureus biofilm was grown in N or MH broths rather than in TS. Besides, glucose addition to the medium decreases the ability to develop biofilm and increase the photoinactivation capacity. Prevention of 3 log biofilm developments was obtained when S. aureus cultures were treated with TAPC (10 μM) and 108 J/cm2 in TS broth and the number of CFU was counted after 24 h. Moreover, microscopy studies demonstrated modifications in biofilm architecture.<br><br>CONCLUSIONS: These results indicate that TAPC and ZnPPc4+ may be promising photosensitizers for photodynamic inactivation of S. aureus biofilms or to prevent their formation.},
}
@article {pmid31004913,
year = {2019},
author = {Lekbach, Y and Li, Z and Xu, D and El Abed, S and Dong, Y and Liu, D and Gu, T and Koraichi, SI and Yang, K and Wang, F},
title = {Salvia officinalis extract mitigates the microbiologically influenced corrosion of 304L stainless steel by Pseudomonas aeruginosa biofilm.},
journal = {Bioelectrochemistry (Amsterdam, Netherlands)},
volume = {128},
number = {},
pages = {193-203},
doi = {10.1016/j.bioelechem.2019.04.006},
pmid = {31004913},
issn = {1878-562X},
abstract = {The mitigation of microbiologically influenced corrosion (MIC) of 304L stainless steel (SS) against Pseudomonas aeruginosa by a Salvia officinalis extract was investigated using electrochemical and surface analysis techniques. The extract was characterized by HPLC-Q-TOF-MS and its antibiofilm property was evaluated. The data revealed the presence of well-known antimicrobial and anticorrosion compounds in the extract. The S. officinalis extract was found effective in preventing biofilm formation and inhibiting mature biofilm. Electrochemical results indicated that P. aeruginosa accelerated the MIC of 304L SS, while the extract was found to prevent the MIC with an inhibition efficiency of 97.5 ± 1.5%. This was attributed to the formation of a protective film by the adsorption of some compounds from the extract on the 304L SS surface.},
}
@article {pmid31002887,
year = {2019},
author = {Kunz, D and Wirth, J and Sculean, A and Eick, S},
title = {In- vitro-activity of additive application of hydrogen peroxide in antimicrobial photodynamic therapy using LED in the blue spectrum against bacteria and biofilm being associated with periodontal disease.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.04.015},
pmid = {31002887},
issn = {1873-1597},
abstract = {BACKGROUND: Although antimicrobial photodynamic therapy (aPDT) has been shown to be efficient in killing planktonic periodontopathogenic bacteria, its activity on established biofilms is very limited. The aim of the present in-vitro study was to evaluate the potential effect of hydrogen peroxide as a pretreatment for aPDT.<br><br>METHODS: aPDT consisting of riboflavin as photosensitizer and illumination by a LED lamp emitting in the blue spectrum for 30 s and 60 s (aPDT60) was combined with a pretreatment with 0.25% and 3% hydrogen peroxide. The antimicrobial activity of these treatments was determined against eight oral species (incl. Porphyromonas gingivalis and Tannerella forsythia) and against eight-species biofilms. Treatment of biofilms in an artificial pocket model included a mechanical removal of the biofilm.<br><br>RESULTS: Against planktonic bacteria, pretreatment with hydrogen peroxide increased killing of planktonic bacteria, after aPDT60 no viable bacteria were detected in 7 of 8 strains. In biofilms formed on well-plates, aPDT60 reduced bacterial counts only by 0.53 log10 cfu, whereas reduction was closed to 4 log10 or higher when 3% hydrogen peroxide was used. When biofilms were treated in the periodontal-pocket model, reduction of cfu was less than 0.5 log10 after mechanical therapy or aPDT60 only, however no bacteria were detected after mechanical biofilm removal followed by the use 3% of hydrogen peroxide and aPDT60.<br><br>CONCLUSIONS: aPDT using riboflavin and blue LED light applied after mechanical removal of biofilm and adjunctive 3% hydrogen peroxide solution appears to represent an alternative for antimicrobial periodontal therapy.},
}
@article {pmid31002106,
year = {2019},
author = {Yu, L and Li, W and Qi, K and Wang, S and Chen, X and Ni, J and Deng, R and Shang, F and Xue, T},
title = {McbR is involved in biofilm formation and H2O2 stress response in avian pathogenic Escherichia coli X40.},
journal = {Poultry science},
volume = {},
number = {},
pages = {},
doi = {10.3382/ps/pez205},
pmid = {31002106},
issn = {1525-3171},
abstract = {Avian pathogenic Escherichia coli (APEC) causes a variety of extraintestinal diseases known as colibacillosis and is responsible for significant economic losses in the poultry industry worldwide. Biofilm formation results in increased morbidity and persistent infections, and is the main reason for the difficult treatment of colibacillosis with antimicrobial agents. It is reported that the transcriptional regulator McbR regulates biofilm formation and mucoidy by repressing the expression of the periplasmic protein YbiM, and activates the transcription of the yciGFE operon by binding to the yciG promoter in E. coli K-12. However, whether McbR regulates biofilm formation and H2O2 stress response in APEC has been not reported. The present study showed that, in the clinical isolate APECX40, the deletion of mcbR increased biofilm formation by upregulating the transcription of the biofilm-associated genes bcsA, fliC, wcaF, and fimA. In addition, the deletion of mcbR decreased H2O2 stress response by downregulating the transcript levels of the stress-associated genes yciF and yciE. The electrophoretic mobility shift assays confirmed that McbR directly binds to the promoter regions of yciG and yciF. This study may provide new clues to understanding gene regulation in APEC.},
}
@article {pmid31001972,
year = {2019},
author = {Wilt, IK and Hari, TPA and Wuest, WM},
title = {Hijacking the Bacterial Circuitry of Biofilm Processes via Chemical &quot;Hot-Wiring&quot;: An Under-explored Avenue for Therapeutic Development.},
journal = {ACS infectious diseases},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsinfecdis.9b00104},
pmid = {31001972},
issn = {2373-8227},
abstract = {Biofilm-associated infections are linked to chronic and recurring illnesses. These infections are often not susceptible to current antibiotic treatments because of the protective exocellular matrix and subpopulations of dormant or &quot;persister&quot; cells. Targeting bacterial circuitry involved in biofilm formation, including two-component systems, quorum sensing, polysaccharide structural integrity, and cyclic nucleotide signaling pathways, has the potential to expand the existing arsenal of therapeutics, thus catalyzing a second golden age of antibiotic development.},
}
@article {pmid31001942,
year = {2019},
author = {Tu, C and Wang, Y and Yi, L and Wang, Y and Liu, B and Gong, S},
title = {[Roles of signaling molecules in biofilm formation].},
journal = {Sheng wu gong cheng xue bao = Chinese journal of biotechnology},
volume = {35},
number = {4},
pages = {558-566},
doi = {10.13345/j.cjb.180326},
pmid = {31001942},
issn = {1000-3061},
abstract = {Bacterial biofilm refers to a tunicate-like biological group composed of polysaccharide, protein and nucleic acid secreted by bacteria on the surface of the mucous membrane or biological material. The biofilm formation is a major cause of chronic infections. Bacteria could produce some secondary metabolites during the growth and reproduction. Some of them act as signaling molecules allowing bacteria to communicate and regulate many important physiological behaviors at multiple-cell level, such as bioluminescence, biofilm formation, motility and lifestyles. Usually, these signal molecules play an important role in the formation of bacterial biofilm. We review here the effects of related signal molecules of Quorum Sensing, cyclic diguanylate, Two-Component Systems and sRNA on the biofilm formation. Focusing on these regulation mechanism of signal molecules in the process of biofilm formation is necessary for the prevention and treatment of some chronic diseases.},
}
@article {pmid31001488,
year = {2019},
author = {Moussouni, M and Nogaret, P and Garai, P and Ize, B and Vivès, E and Blanc-Potard, AB},
title = {Activity of a Synthetic Peptide Targeting MgtC on Pseudomonas aeruginosa Intramacrophage Survival and Biofilm Formation.},
journal = {Frontiers in cellular and infection microbiology},
volume = {9},
number = {},
pages = {84},
doi = {10.3389/fcimb.2019.00084},
pmid = {31001488},
issn = {2235-2988},
abstract = {Antivirulence strategies aim to target pathogenicity factors while bypassing the pressure on the bacterium to develop resistance. The MgtC membrane protein has been proposed as an attractive target that is involved in the ability of several major bacterial pathogens, including Pseudomonas aeruginosa, to survive inside macrophages. In liquid culture, P. aeruginosa MgtC acts negatively on biofilm formation. However, a putative link between these two functions of MgtC in P. aeruginosa has not been experimentally addressed. In the present study, we first investigated the contribution of exopolysaccharides (EPS) in the intramacrophage survival defect and biofilm increase of mgtC mutant. Within infected macrophages, expression of EPS genes psl and alg was increased in a P. aeruginosa mgtC mutant strain comparatively to wild-type strain. However, the intramacrophage survival defect of mgtC mutant was not rescued upon introduction of psl or alg mutation, suggesting that MgtC intramacrophage role is unrelated to EPS production, whereas the increased biofilm formation of mgtC mutant was partially suppressed by introduction of psl mutation. We aimed to develop an antivirulence strategy targeting MgtC, by taking advantage of a natural antagonistic peptide, MgtR. Heterologous expression of mgtR in P. aeruginosa PAO1 was shown to reduce its ability to survive within macrophages. We investigated for the first time the biological effect of a synthetic MgtR peptide on P. aeruginosa. Exogenously added synthetic MgtR peptide lowered the intramacrophage survival of wild-type P. aeruginosa PAO1, thus mimicking the phenotype of an mgtC mutant as well as the effect of endogenously produced MgtR peptide. In correlation with this finding, addition of MgtR peptide to bacterial culture strongly reduced MgtC protein level, without reducing bacterial growth or viability, thus differing from classical antimicrobial peptides. On the other hand, the addition of exogenous MgtR peptide did not affect significantly biofilm formation, indicating an action toward EPS-independent phenotype rather than EPS-related phenotype. Cumulatively, our results show an antivirulence action of synthetic MgtR peptide, which may be more potent against acute infection, and provide a proof of concept for further exploitation of anti-Pseudomonas strategies.},
}
@article {pmid31001485,
year = {2019},
author = {Fleitas Martínez, O and Cardoso, MH and Ribeiro, SM and Franco, OL},
title = {Recent Advances in Anti-virulence Therapeutic Strategies With a Focus on Dismantling Bacterial Membrane Microdomains, Toxin Neutralization, Quorum-Sensing Interference and Biofilm Inhibition.},
journal = {Frontiers in cellular and infection microbiology},
volume = {9},
number = {},
pages = {74},
doi = {10.3389/fcimb.2019.00074},
pmid = {31001485},
issn = {2235-2988},
abstract = {Antimicrobial resistance constitutes one of the major challenges facing humanity in the Twenty-First century. The spread of resistant pathogens has been such that the possibility of returning to a pre-antibiotic era is real. In this scenario, innovative therapeutic strategies must be employed to restrict resistance. Among the innovative proposed strategies, anti-virulence therapy has been envisioned as a promising alternative for effective control of the emergence and spread of resistant pathogens. This review presents some of the anti-virulence strategies that are currently being developed, it will cover strategies focused on quench pathogen quorum sensing (QS) systems, disassemble of bacterial functional membrane microdomains (FMMs), disruption of biofilm formation and bacterial toxin neutralization.},
}
@article {pmid31001340,
year = {2019},
author = {Kallick, E and Nistico, L and Longwell, M and Byers, B and Cartieri, F and Kreft, R and Edington, H},
title = {Resistance of Synthetic and Biologic Surgical Meshes to Methicillin-Resistant Staphylococcus aureus Biofilm: An In Vitro Investigation.},
journal = {International journal of biomaterials},
volume = {2019},
number = {},
pages = {1063643},
doi = {10.1155/2019/1063643},
pmid = {31001340},
issn = {1687-8787},
abstract = {Surgical meshes have become the standard procedure for a variety of surgical applications with 20 million meshes being implanted each year. The popularity of mesh usage among surgeons is backed by the multiple studies that support its functionality as a tool for improving surgical outcomes. However, their use has also been associated with infectious surgical complications and many surgeons have turned to biologic meshes. While there have been several studies investigating synthetic meshes, there is limited data comparing synthetic and biologic meshes in vitro in an infection model. This study evaluates the in vitro susceptibility of both synthetic and biologic meshes to single-species methicillin-resistant Staphylococcus aureus (MRSA) biofilms. This research compares biofilm biomass, average thickness, and coverage between the three meshes through florescent in situ hybridization (FISH), confocal scanning microscopy (CSLM), and image analysis. We also report the varying levels of planktonic and attached bacteria through sonication and cfu counts. While the data illustrates increased biofilm formation on biologic mesh in vitro, the study must further be investigated in vivo to confirm the study observations.},
}
@article {pmid31001240,
year = {2019},
author = {Reichhardt, C and Parsek, MR},
title = {Confocal Laser Scanning Microscopy for Analysis of Pseudomonas aeruginosa Biofilm Architecture and Matrix Localization.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {677},
doi = {10.3389/fmicb.2019.00677},
pmid = {31001240},
issn = {1664-302X},
support = {R01 AI077628/AI/NIAID NIH HHS/United States ; R01 AI097511/AI/NIAID NIH HHS/United States ; },
abstract = {Most microbes can produce surface-associated or suspended aggregates called biofilms, which are encased within a biopolymer-rich matrix. The biofilm matrix provides structural integrity to the aggregates and shields the resident cells against environmental stressors, including antibiotic treatment. Microscopy permits examination of biofilm structure in relation to the spatial localization of important biofilm matrix components. This review highlights microscopic approaches to investigate bacterial biofilm assembly, matrix composition, and localization using Pseudomonas aeruginosa as a model organism. Initial microscopic investigations provided information about the role key matrix components play in elaborating biofilm aggregate structures. Additionally, staining of matrix components using specific labels revealed distinct positioning of matrix components within the aggregates relative to the resident cells. In some cases, it was found that individual matrix components co-localize within aggregates. The methodologies for studying the biofilm matrix are continuing to develop as our studies reveal novel aspects of its composition and function. We additionally describe some outstanding questions and how microscopy might be used to identify the functional aspects of biofilm matrix components.},
}
@article {pmid31000791,
year = {2019},
author = {Kim, SG and Jun, JW and Giri, SS and Yun, S and Kim, HJ and Kim, SW and Kang, JW and Han, SJ and Jeong, D and Park, SC},
title = {Isolation and characterisation of pVa-21, a giant bacteriophage with anti-biofilm potential against Vibrio alginolyticus.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {6284},
doi = {10.1038/s41598-019-42681-1},
pmid = {31000791},
issn = {2045-2322},
support = {2017R1C1B2004616//National Research Foundation of Korea (NRF)/ ; PJ013985032018//Rural Development Administration (RDA)/ ; },
abstract = {There is an increasing emergence of antibiotic-resistant Vibrio alginolyticus, a zoonotic pathogen that causes mass mortality in aquatic animals and infects humans; therefore, there is a demand for alternatives to antibiotics for the treatment and prevention of infections caused by this pathogen. One possibility is through the exploitation of bacteriophages. In the present study, the novel bacteriophage pVa-21 was classified as Myoviridae and characterised as a candidate biocontrol agent against V. alginolyticus. Its morphology, host range and infectivity, growth characteristics, planktonic or biofilm lytic activity, stability under various conditions, and genome were investigated. Its latent period and burst size were estimated to be approximately 70 min and 58 plaque-forming units/cell, respectively. In addition, phage pVa-21 can inhibit bacterial growth in both the planktonic and biofilm states. Furthermore, phylogenetic and genome analysis revealed that the phage is closely related to the giant phiKZ-like phages and can be classified as a new member of the phiKZ-like bacteriophages that infect bacteria belonging to the family Vibrionaceae.},
}
@article {pmid31000317,
year = {2019},
author = {Iliescu Nelea, M and Paek, L and Dao, L and Rouchet, N and Efanov, JI and Édouard, C and Danino, MA},
title = {In-situ characterization of the bacterial biofilm associated with Xeroform™ and Kaltostat™ dressings and evaluation of their effectiveness on thin skin engraftment donor sites in burn patients.},
journal = {Burns : journal of the International Society for Burn Injuries},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.burns.2019.02.024},
pmid = {31000317},
issn = {1879-1409},
abstract = {Biofilm forms when bacteria surrounded by an extracellular matrix aggregate on a surface. It can develop on many surfaces, including wound dressings; this can be particularly nefarious for burn patients undergoing skin grafting (autograft) for burn wound coverage as they often suffer from compromised immune system function. Autograft donor sites are particularly vulnerable to biofilm formation; as such, timely healing of these sites is essential. Our aim was to apply scanning electron microscopy to compare the efficacy of two types of wound dressings in preventing the formation of bacterial biofilm on burn patient skin graft donor sites. One dressing contained bismuth tribromophenate at a concentration of 3% which confers it bacteriostatic properties (Xeroform™). The other was an absorptive alginate calcium sodium dressing (Kaltostat™). Samples of each wound dressing, which were in contact with the skin graft donor site, were prepared for analysis under the scanning electron microscope (SEM) using an original method developed by our research group that aims to maintain the integrity of the biofilm microstructure. Samples prepared by this method were then analyzed using SEM, which allowed the characterization of biofilm and the evaluation of bacterial density on the studied dressing samples. To this day, this imaging technique has been rarely employed for dressing analysis and this is the first time that it is employed for in situ biofilm visualization for this particular application.},
}
@article {pmid30999180,
year = {2019},
author = {Xia, S and Xu, X and Zhou, L},
title = {Insights into selenate removal mechanism of hydrogen-based membrane biofilm reactor for nitrate-polluted groundwater treatment based on anaerobic biofilm analysis.},
journal = {Ecotoxicology and environmental safety},
volume = {178},
number = {},
pages = {123-129},
doi = {10.1016/j.ecoenv.2019.04.005},
pmid = {30999180},
issn = {1090-2414},
abstract = {The selenate removal mechanism of hydrogen-based membrane biofilm reactor (MBfR) for nitrate-polluted groundwater treatment was studied based on anaerobic biofilm analysis. A laboratory-scale MBfR was operated for over 60 days with electron balance, structural analysis, and bacterial community identification. Results showed that anaerobic biofilm had an excellent removal of both selenate (95%) and nitrate (100%). Reduction of Selenate → Selenite → Se0 with hydrogen was the main pathway of anaerobic biofilm for selenate removal with amorphous Se0 precipitate accumulating in the biofilm. The element selenium was observed to be evenly distributed along the cross-sectional thin biofilm. A part of selenate (3%) was also reduced into methyl-selenide by heterotrophic bacteria. Additionally, Hydrogenophaga bacteria of β-Proteobacteria, capable of both nitrate and selenate removal, worked as the dominant species (over 85%) in the biofilm and contributed to the stable removal of both nitrate and selenate. With the selenate input, bacteria with a capacity for both selenate and nitrate removal were also developed in the anaerobic biofilm community.},
}
@article {pmid30998780,
year = {2019},
author = {Waseem, M and Williams, JQL and Thangavel, A and Still, PC and Ymele-Leki, P},
title = {A structural analog of ralfuranones and flavipesins promotes biofilm formation by Vibrio cholerae.},
journal = {PloS one},
volume = {14},
number = {4},
pages = {e0215273},
doi = {10.1371/journal.pone.0215273},
pmid = {30998780},
issn = {1932-6203},
abstract = {Phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS) is a highly conserved, multistep chemical process which uses phosphate transfer to regulate the intake and use of sugars and other carbohydrates by bacteria. In addition to controlling sugar uptake, the PTS regulates several bacterial cellular functions such as chemotaxis, glycogen metabolism, catabolite repression and biofilm formation. Previous studies have shown that the phosphoenolpyruvate (PEP) to pyruvate ratio is a critical determinant of PTS functions. This study shows that 2-oxo-4-phenyl-2,5-dihydro-3-furancarbonitrile (MW01), a compound with structural similarity to known natural products, induces Vibrio cholerae to grow preferentially in the biofilm mode in a mechanism that involves interaction with pyruvate. Spectrophotometric assays were used to monitor bacterial growth kinetics in microtiter plates and quantitatively evaluate biofilm formation in borosilicate glass tubes. Evidence of MW01 and pyruvate interactions was determined by nuclear magnetic resonance spectroscopy. Given the established connection between PTS activity and biofilm formation, this study also highlights the potential impact that small-molecule modulators of the PTS may have in the development of innovative approaches to manage desired and undesired microbial cultures in clinical, industrial and environmental settings.},
}
@article {pmid30998699,
year = {2019},
author = {Goc, A and Sumera, W and Niedzwiecki, A and Rath, M},
title = {10-undecynoic acid is a new anti-adherent agent killing biofilm of oral Streptococcus spp.},
journal = {PloS one},
volume = {14},
number = {4},
pages = {e0214763},
doi = {10.1371/journal.pone.0214763},
pmid = {30998699},
issn = {1932-6203},
abstract = {In the search for novel agents against oral pathogens in their planktonic and biofilm form, we have focused our attention on 10-undecynoic acid as the representative of the acetylenic fatty acids. Using macro-broth susceptibility testing method we first established MIC value. Next, the MBC value was determined from a broth dilution minimum inhibitory concentration test by sub-culturing it to BHI agar plates that did not contain the test agent. Anti-biofilm efficacy was tested in 96-well plates coated with saliva using BHI broth supplemented with 1% sucrose as a standard approach. Based on obtained results, MIC value for 10-undecynoic acid was established to be 2.5 mg/ml and the MBC value to be 5 mg/ml. The MBIC90 showed to be 2.5 mg/ml, however completed inhibition of biofilm formation was achieved at 5.0 mg/ml. MBBC concentration revealed to be the same as MBC value, causing approximately 30% reduction at the same time in biomass of pre-existing biofilm, whereas application of 7.0 mg/ml of 10-undecynoic acid crossed the 50% eradication mark. Strong anti-adherent effect was observed upon 10-undecynoic acid application at sub-MBC concentrations as well, complemented with suppression of acidogenicity and aciduricity. Thus, we concluded that 10-undecynoic acid might play an important role in the development of alternative or adjunctive antibacterial and anti-biofilm preventive and/or therapeutic approaches.},
}
@article {pmid30998111,
year = {2019},
author = {Nwabor, OF and Vongkamjan, K and Voravuthikunchai, SP},
title = {Antioxidant Properties and Antibacterial Effects of Eucalyptus camaldulensis Ethanolic Leaf Extract on Biofilm Formation, Motility, Hemolysin Production, and Cell Membrane of the Foodborne Pathogen Listeria monocytogenes.},
journal = {Foodborne pathogens and disease},
volume = {},
number = {},
pages = {},
doi = {10.1089/fpd.2019.2620},
pmid = {30998111},
issn = {1556-7125},
abstract = {Consumer concerns toward chemical preservatives have resulted in increased search for healthy green alternative. In this study, the antioxidant activity and antibacterial effects of Eucalyptus camaldulensis ethanolic leaf extract against Listeria monocytogenes, a serious foodborne pathogen, was evaluated. Total phenolic and flavonoid contents of the extract were 11.10 mg garlic acid equivalent/mg extract and 15.05 mg quercetin equivalent/mg extract, respectively. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration of the extract was 64-128 μg/mL and 256-512 μg/mL, respectively. Time-kill assay revealed growth inhibitory effects after 4-h treatment of the bacteria with the extract. A reduction of ≈2-3 log colony-forming units per milliliter was observed against the tested food and environmental isolates after challenging the pathogens with the extract at MIC for 6 h. Sub-MICs of the extract significantly inhibited motility and listeriolysin O production up to 80%, with 60% inhibition of biofilm formation (p < 0.05). Antioxidant assay revealed free radical scavenging activity with 50% inhibitory concentration (IC50) of 57.07 μg/mL for 2,2-diphenyl-1-picrylhydrazyl and 29.01 μg/mL for ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] assay. Ferric reducing antioxidant power assay further showed a total antioxidant power equivalent to 92.93 μM ascorbic acid equivalent/mg extract. As the extract exhibited profound antilisterial activity and good radical scavenging ability, it might serve as a potential alternative source of biopreservative agent against L. monocytogenes.},
}
@article {pmid30996828,
year = {2019},
author = {Bahador, N and Shoja, S and Faridi, F and Dozandeh-Mobarrez, B and Qeshmi, FI and Javadpour, S and Mokhtary, S},
title = {Molecular detection of virulence factors and biofilm formation in Pseudomonas aeruginosa obtained from different clinical specimens in Bandar Abbas.},
journal = {Iranian journal of microbiology},
volume = {11},
number = {1},
pages = {25-30},
pmid = {30996828},
issn = {2008-3289},
abstract = {Background and Objectives: Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen. The presence of several virulence factors such as exotoxin and exoenzyme genes and biofilm may contribute to its pathogenicity. The purpose of this study was to investigate the presence of toxA, exoU and exoS, the determination of biofilm production and antimicrobial susceptibility patterns among clinical isolates of P. aeruginosa.<br><br>Materials and Methods: In this study, 75 isolates of P. aeruginosa were recovered from various clinical specimens. Antimicrobial susceptibility pattern of isolates were identified. Virulence genes toxA, exoU and exoS were determined using PCR. The ability of biofilm production was assessed.<br><br>Results: Antimicrobial susceptibility test showed that 12 strains were resistant to more than 8 antibiotics (17.14%). The most effective antibiotic was colistin as 98.6% of isolates were sensitive. The frequencies of exoU and exoS genes were detected as 36.6% and 55.7%, respectively. In addition, 98.6% of the isolates were biofilm producers. Exotoxin A was detected in sixty-eight isolates (95.7%).<br><br>Conclusion: The findings of this study showed that, the presence of P. aeruginosa exotoxin and exoenzyme genes, particularly, the exoU gene is the most common virulence factors in the bacterial isolates from urine samples. Biofilm is a serious challenge in the treatment of P. aeruginosa infection.},
}
@article {pmid30996209,
year = {2019},
author = {Minami, M and Takase, H and Nakamura, M and Makino, T},
title = {Methanol extract of Lonicera caerulea var. emphyllocalyx fruit has antibacterial and anti-biofilm activity against Streptococcus pyogenes in vitro.},
journal = {Bioscience trends},
volume = {},
number = {},
pages = {},
doi = {10.5582/bst.2019.01005},
pmid = {30996209},
issn = {1881-7823},
abstract = {Streptococcus pyogenes causes several infectious diseases such as tonsillitis, cellulitis, and streptococcal toxic shock syndrome. As antibiotics are used for the general treatment of S. pyogenes infection, cases of treatment failure due to drug-resistant bacteria have increased. Lonicera caerulea var. emphyllocalyx (LCE) has been used as a folk medicine in northern Japan (Hokkaido). In this study, we investigated the antibacterial effect of methanol extracts of the fruit, stem, and leaf of LCE (LCEEs) against S. pyogenes using disk diffusion assay. As LCEE (fruit) had the strongest antibacterial activity among the three LCEEs, we focused on functional analysis of antibacterial effects of LCEE (fruit). LCEE (fruit) suppressed the growth of S. pyogenes in a dose-dependent manner. Morphological analysis by transmission electron microscopy demonstrated that LCEE (fruit) damaged the shape of S. pyogenes. Microplate and confocal laser microscopy analysis showed that biofilm formation was also suppressed by LCEE (fruit) in a dose-dependent manner. To further evaluate the surface structure of these biofilms, we performed hydrophobic analysis, which demonstrated that LCEE (fruit) reduced the hydrophobicity of the bacterial surface structure. Our data demonstrated that LCEE (fruit) had anti-bacterial and anti-biofilm effects on S. pyogenes in vitro, suggesting that the direct anti-bacterial effects of the LCEE (fruit) may be useful for treatment of local S. pyogenes infection.},
}
@article {pmid30995873,
year = {2019},
author = {Osman, K and Orabi, A and Elbehiry, A and Hanafy, MH and Ali, AM},
title = {Pseudomonas species isolated from camel meat: quorum sensing-dependent virulence, biofilm formation and antibiotic resistance.},
journal = {Future microbiology},
volume = {},
number = {},
pages = {},
doi = {10.2217/fmb-2018-0293},
pmid = {30995873},
issn = {1746-0921},
abstract = {Aim: This research pioneers the process of obtaining information concerning the distribution and existence of seven ESBL genes linked to Pseudomonas, three virulence and five quorum sensing separated from 100 camel meat samples using PCR. Materials and methods: The Vitek system was used to identify Pseudomonas species. Phenotypic antibiotic resistance of 16 antibiotics was tested by disc diffusion. Quantification of pyocyanin, elastase, alkaline protease, biofilm and Vero cell cytotoxicity was also implemented. Results: The total number of Pseudomonas species isolated from camel meat was 10/100 identified as Pseudomonas aeruginosa 8/10, Pseudomonas fluorescens 2/10. The isolates were multidrug resistant and were resistant to four to eight antibiotics representing four to six classes. The 15 genes exhibited a huge diversity in their association. Conclusion: The results indicated that camel meat is an unpropitious hotbed for Pseudomonas species of clinical significance.},
}
@article {pmid30995575,
year = {2019},
author = {Wu, M and Luo, JH and Hu, S and Yuan, Z and Guo, J},
title = {Perchlorate bio-reduction in a methane-based membrane biofilm reactor in the presence and absence of oxygen.},
journal = {Water research},
volume = {157},
number = {},
pages = {572-578},
doi = {10.1016/j.watres.2019.04.008},
pmid = {30995575},
issn = {1879-2448},
abstract = {Perchlorate has been widely detected in various water environments and could cause serious health problems. Methane has been proposed as a promising electron donor to remove perchlorate from contaminated water, yet it is unclear whether and how microbial methane oxidation couples with perchlorate reduction, in particular under anoxic conditions. Here, the feasibility and performance of perchlorate reduction driven by methane in the presence and absence of oxygen were investigated and compared in a lab-scale methane-based membrane biofilm reactor. Long-term operational performance suggested that perchlorate was reduced to chloride, with 4 mg Cl/L/d of perchlorate removal rate under anoxic conditions. Differently, perchlorate removal rate increased to 16 mg Cl/L/d, and volatile fatty acids (VFAs) were produced from methane partial oxidation when a limited oxygen (10 mg/L/d) was externally supplied. Regardless of oxygen conditions, microbial perchlorate reduction driven by methane might be mediated through synergistic interactions by a microbial consortium, but with different key microbial members under both oxygen regimes. Under anoxic conditions, aerobic methanotrophs (likely Methylocystaceae and Methylococcaceae) might micro-aerobically oxidize methane by utilizing internal oxygen from microbial perchlorate reduction, which might be mediated by Rhodocyclaceae. In contrast, under oxygen-limiting conditions, methanogens (e.g., Methanosarcina) and fermenters (e.g., Veillonellaceae) likely jointly converted methane into VFAs, then dissimilatory perchlorate-reducing bacteria (e.g., Rhodocyclaceae) utilized the produced VFAs to reduce perchlorate to chloride. Our findings provide evidence to link methane oxidation with perchlorate reduction under both oxygen regimes, which could be facilitated to design a process to remove perchlorate from groundwater.},
}
@article {pmid30995521,
year = {2019},
author = {Ivan, K and Budimir, A and Bošnjak, Z and Jakovljević, S and Anić, I},
title = {The photo-activated and photo-thermal effect of the 445/970 nm diode laser on the mixed biofilm inside root canals of human teeth in vitro: a pilot study.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.04.014},
pmid = {30995521},
issn = {1873-1597},
abstract = {AIMS: 1) Evaluation of the photo-thermal (PT) and photo-activated (PAD) antibacterial effect of the 445/970 nm diode laser on E. faecalis, S. aureus and C. albicans mixed biofilms grown together inside root canals of human teeth. 2) Defining a potentially efficient clinical protocol for safe and predictable usage in endodontic procedures.<br><br>METHODOLOGY: The root canals of 100 extracted human teeth with single straight canals were prepared with ProTaper NEXT files, sterilized, contaminated with a combination of three cultures (E. faecalis, S. aureus, C. albicans) and incubated for 15 days. The samples were randomly distributed into three groups (n = 20) and treated as follows: Group 1 (G1) - the 445 nm photo-thermal (PT) effect, Group 2 (G2) - a combination of the 445 nm and 970 nm PT effect, Group 3 (G3) - the 445 nm photo-activated (PAD) effect with 0.1% riboflavin, Group 4 (G4) - a combination of 3% sodium hypochlorite (NaOCl) and the 445 nm PAD effect. Four samples were used as positive control (non-treated) and four as a negative control. 12 aditional samples were used as a control for the G4 (3% NaOCl rinse without the laser). The number of viable microbes in each canal was determined by the colony forming unit (CFU) count.<br><br>RESULTS: A statistically significant reduction in the microbial population after all treatments was observed (P < 0.001). Groups 2 and 3 showed similar results, both better than Group 1. Group 4 produced the best results.<br><br>CONCLUSIONS: The 445 nm PAD protocol has a stronger antimicrobial effect than the 445 nm PT protocol. Prolonged exposure time to laser light and a combination of wavelengths (445/970 PT protocol) helps in the reduction of microbes. C. albicans appears to be more sensitive to laser irradiation than the other bacteria tested in this study. Following current results, tested laser protocols could be recommended for clinical usage but only as an adjunct to &quot;classic&quot; NaOCl rinse since alone they are not able to completely eradicate all microorganisms.},
}
@article {pmid30995049,
year = {2019},
author = {Blakeman, JT and Morales-García, AL and Mukherjee, J and Gori, K and Hayward, AS and Lant, NJ and Geoghegan, M},
title = {Extracellular DNA Provides Structural Integrity to a Micrococcus luteus Biofilm.},
journal = {Langmuir : the ACS journal of surfaces and colloids},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.langmuir.9b00297},
pmid = {30995049},
issn = {1520-5827},
abstract = {Force spectroscopy was used to show that extracellular DNA (eDNA) has a pre-eminent structural role in a biofilm. The adhesive behavior of extracellular polymeric substances to poly(ethylene terephthalate), a model hydrophobic surface, was measured in response to their degradation by hydrolytic enzymes known for their biofilm dispersion potential: DNaseI, protease, cellulase, and mannanase. Only treatment with DNaseI significantly decreased the adhesive force of the model bacterium Micrococcus luteus with the surface, and furthermore this treatment almost completely eliminated any components of the biofilm maintaining the adhesion, establishing a key structural role for eDNA.},
}
@article {pmid30994755,
year = {2019},
author = {Curvelo, JAR and Moraes, DC and Anjos, CAD and Portela, MB and Soares, RMA},
title = {Histatin 5 and human lactoferrin inhibit biofilm formation of a fluconazole resistant Candida albicans clinical isolate.},
journal = {Anais da Academia Brasileira de Ciencias},
volume = {91},
number = {1},
pages = {e20180045},
doi = {10.1590/0001-3765201920180045},
pmid = {30994755},
issn = {1678-2690},
abstract = {Candida albicans is the most important fungal pathogen that causes infections in humans. Biofilms are hard-to-treat structures due to their high antifungal resistance. Saliva is a fluid that contains antimicrobial substances acting as the first-line of defense against pathogens, and its immune components may be potential tools for the discovery of new treatments against candidiasis. To evaluate the activity of histatin 5 and human lactoferrin against biofilm formation. A fluconazole-resistant Candida albicans clinical isolate was used as the model microorganism. Morphogenesis was evaluated by differential counting. Biofilm quantification was performed by XTT reduction assay. Thickness and topography of biofilms were assessed through confocal laser scanning microscopy (CLSM). Histatin 5 inhibited yeast-to-hyphae transition in a dose-dependent manner, while the effect of human lactoferrin on this process was inversely proportional to its concentration. Both compounds were able to significantly inhibit biofilm metabolic activity. Histatin 5 reduced biofilm thickness. Histatin 5 and human lactoferrin exhibited in vitro cytotoxicity against a fluconazole-resistant Candida albicans biofilm, which points to the potential application of these compounds in the treatment of biofilms formed by this fungus, especially in resistant infections.},
}
@article {pmid30993384,
year = {2019},
author = {RedCorn, RM and Hillman, ET and Solomon, KV and Engelberth, AS},
title = {Xanthobacter-dominated biofilm as a novel source for high-value rhamnose.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-019-09765-4},
pmid = {30993384},
issn = {1432-0614},
support = {FP-91780201-0//EPA STAR/ ; },
abstract = {Rhamnose is a high-value carbohydrate used in flavorings, aromatics, and pharmaceuticals. Current demand for rhamnose is filled through plant-based sources; however, microbially originated rhamnolipids have been proposed as an alternative source. A mixed microbial biofilm, cultured from a wastewater sludge, was found to comprise > 8 dry weight% rhamnose when provided volatile fatty acids as carbon source, and 24 dry weight% when given glucose. The latter rhamnose concentration is a fourfold higher production mass than the current plant-based origin and is competitive with yields from pure microbial cultures. The biofilm was characterized based on total carbohydrate production at varying nutrient levels, individual carbohydrate monomer production from varying organic acid substrates, and microbial community composition-based on 16s rRNA. Biofilm carbohydrate production was maximized at a C:N ratio of 28 (mol:mol). The production of rhamnose varied significantly based on carbon substrate; glucose had the greatest yield of rhamnose, followed by propionic acid, lactic acid, acetic acid, valeric acid, and butyric acid. Microbial community analysis indicated an abundance of organisms within the Xanthobacter genus, which is known to produce rhamnose as zeaxanthin rhamnoside. Rhamnose production was heavily correlated with ribose production (R2 = 0.96). Results suggest that mixed microbial biofilms could be a competitive source of monomeric rhamnose that may be produced from mixed organic waste streams of variable composition via volatile fatty acids and glucose.},
}
@article {pmid30991917,
year = {2019},
author = {Rumyantceva, V and Rumyantceva, V and Koshel, E and Vinogradov, V},
title = {Biocide-conjugated magnetite nanoparticles as an advanced platform for biofilm treatment.},
journal = {Therapeutic delivery},
volume = {10},
number = {4},
pages = {241-250},
doi = {10.4155/tde-2019-0011},
pmid = {30991917},
issn = {2041-6008},
abstract = {Biofilm-related diseases contribute to patient morbidity, increased mortality and represent a considerable economic burden. Despite numerous developments in the field of combating biofilms, the most effective treatment method is still the mechanical removal of biofilms or the replacement of a device overgrown with biofilm. Given that the main challenges are the mechanical stability of biofilms, low penetration of biocides and the persistence of cells with reduced metabolic status in them, a promising direction is the use of magnetically controlled materials for their treatment. Current review discusses recent applications of magnetite-based materials as biocide delivery carriers and effectiveness of these conjugates against biofilms.},
}
@article {pmid30991317,
year = {2019},
author = {Yao, Y and Habimana, O},
title = {Biofilm research within irrigation water distribution systems: Trends, knowledge gaps, and future perspectives.},
journal = {The Science of the total environment},
volume = {673},
number = {},
pages = {254-265},
doi = {10.1016/j.scitotenv.2019.03.464},
pmid = {30991317},
issn = {1879-1026},
abstract = {Biofilms in irrigation water distribution systems (IWDSs) play an essential role in spreading pathogens, chemical pollutants, and environmental pollutants into downstream irrigated crops and thus should be considered a potential threat to food safety. Although the role of biofilms in drinking water distribution systems has been extensively studied in the last decade, the research on IWDS biofilms in this period has been limited. This review identifies research gaps in the field of IWDS biofilms, provides perspectives on experimental designs for investigating IWDS biofilms, and suggests potential strategies worth pursuing in IWDS management. The current state of the art of IWDS biofilms is discussed, and an analysis of the challenges in IWDS biofilm research is presented. Furthermore, this review proposes useful advanced technologies that allow a practical, in-depth fundamental understanding of IWDS biofilms. In a nutshell, this article provides future directions and insights into detailed experimental designs on a relatively under-reported research topic: &quot;IWDS biofilms.&quot;},
}
@article {pmid30990402,
year = {2019},
author = {Mirzaei, B and Mousavi, SF and Babaei, R and Bahonar, S and Siadat, SD and Shafiee Ardestani, M and Shahrooei, M and Van Eldere, J},
title = {Synthesis of conjugated PIA-rSesC and immunological evaluation against biofilm-forming Staphylococcuse epidermidis.},
journal = {Journal of medical microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1099/jmm.0.000910},
pmid = {30990402},
issn = {1473-5644},
abstract = {PURPOSE: Staphylococcus epidermidis is an opportunistic pathogen and a leading cause of morbidity and premature mortality in patients with medical device-related infections, which is a concern in hospitalized patients. Developing a strategy to raise opsonic antibodies against polysaccharide intracellular adhesin (PIA) could be promising for the elimination of colonizing and biofilm-forming S. epidermidis. Following the purification of truncated rSesC protein and PIA, for the first time, PIA was conjugated to rSesC as a carrier to increase the immunogenicity of PIA and its efficacy in mice was evaluated. The structure of the conjugate was analysed using the Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy (H1- NMR) methods. Afterwards, the immune response was evaluated by measuring the total IgG, IgG2a and IgG2b titres.<br><br>RESULTS: The immunization of mice with the PIA-rSesC conjugate raised the levels of opsonic antibodies, and the vaccinated mice were protected when challenged intravenously by wild-type S. epidermidis strain 1457. Further studies indicated that the conjugated vaccine was able to eliminate S. epidermidis biofilm formation in in vitro or in vivo assays.<br><br>CONCLUSION: This study confirms the proposal that the immunization of mice with PIA-rSesC conjugate vaccine could protect against S. epidermidis infection.},
}
@article {pmid30988059,
year = {2019},
author = {Köseoğlu, VK and Hall, CP and Rodríguez-López, EM and Agaisse, H},
title = {The autotransporter IcsA promotes Shigella flexneri biofilm formation in presence of bile salts.},
journal = {Infection and immunity},
volume = {},
number = {},
pages = {},
doi = {10.1128/IAI.00861-18},
pmid = {30988059},
issn = {1098-5522},
abstract = {Shigella flexneri is an intracellular bacterial pathogen that invades epithelial cells in the colonic mucosa, leading to bloody diarrhea. A previous study showed that S. flexneri forms biofilm in the presence of bile salts, through an unknown mechanism. Here, we investigated the potential role of adhesin-like autotransporter proteins in S. flexneri biofilm formation. BLAST search analysis revealed that the S. flexneri 2457T genome harbors 4 genes, S1242, S1289, S2406 and icsA, encoding adhesin-like autotransporter proteins. Deletion mutants of S1242, S1289, S2406 and icsA genes were generated and tested for biofilm formation. Phenotypic analysis of the mutant strains revealed that disruption of icsA abolished bile salts-induced biofilm formation. IcsA is an outer membrane protein secreted at the bacterial pole that is required for S. flexneri actin-based motility during intracellular infection. In extracellular biofilms, IcsA was also secreted at the bacterial pole and mediated bacterial cell-cell contacts and aggregative growth in the presence of bile salts. Dissecting individual roles of bile salts showed that deoxycholate is a robust biofilm inducer compared to cholate. The release of the extracellular domain of IcsA through IcsP-mediated cleavage was greater in the presence of cholate, suggesting that the robustness of biofilm formation was inversely correlated with IcsA processing. Accordingly, deletion of icsP abrogated IcsA processing in biofilms and enhanced biofilm formation.},
}
@article {pmid30988033,
year = {2019},
author = {Cherny, KE and Sauer, K},
title = {Pseudomonas aeruginosa requires the DNA-specific endonuclease EndA to degrade eDNA to disperse from the biofilm.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00059-19},
pmid = {30988033},
issn = {1098-5530},
abstract = {The dispersion of biofilms is an active process resulting in the release of planktonic cells from the biofilm structure. While much is known about the process of dispersion cue perception and the subsequent modulation of the c-di-GMP pool, little is known about subsequent events resulting in the release of cells from the biofilm. Given that dispersion coincides with void formation and an overall erosion of the biofilm structure, we asked whether dispersion involves degradation of the biofilm matrix. Here, we focused on eDNA due to its almost universal presence in the matrix of biofilm-forming species. We identified two probable nucleases, endA and eddB, and eddA encoding a phosphatase, to be significantly increased in transcript abundance in dispersed cells. However, only inactivation of endA but not eddA or eddB impaired dispersion by P. aeruginosa biofilms in response to glutamate and NO. Heterologously produced EndA was found to be secreted and active in degrading genomic DNA. While endA inactivation had little effect on biofilm formation and the presence of eDNA in biofilms, eDNA degradation upon induction of dispersion was impaired. In contrast, induction of endA expression coincided with eDNA degradation and resulted in biofilm dispersion. Thus released cells demonstrated a hyperattaching phenotype but remained as resistant to tobramycin as biofilm cells from which they egress, indicating EndA-dispersed cells adopted some but not all of the phenotypes associated with dispersed cells. Our findings indicate for the first time a role of DNAse EndA in dispersion, and suggest weakening of the biofilm matrix to be a requisite for biofilm dispersion.IMPORTANCEThe finding that exposure to DNase-I impairs biofilm formation or leads to the dispersal of early stage biofilms has led to the realization of extracellular genomic DNA (eDNA) being a structural component of the biofilm matrix. However, little is known about the contribution of intrinsic DNases to the weakening of the biofilm matrix and dispersion of established biofilms. Here, we demonstrate for the first time that nucleases are induced in dispersed P. aeruginosa cells, are essential to the dispersion response, and that degradation of matrix eDNA by endogenously produced/secreted EndA is required for P. aeruginosa biofilm dispersion. Our findings suggest that dispersing cells mediate their active release from the biofilm matrix via the induction of nucleases.},
}
@article {pmid30987163,
year = {2019},
author = {Khan, F and Manivasagan, P and Lee, JW and Pham, DTN and Oh, J and Kim, YM},
title = {Fucoidan-Stabilized Gold Nanoparticle-Mediated Biofilm Inhibition, Attenuation of Virulence and Motility Properties in Pseudomonas aeruginosa PAO1.},
journal = {Marine drugs},
volume = {17},
number = {4},
pages = {},
doi = {10.3390/md17040208},
pmid = {30987163},
issn = {1660-3397},
support = {20150220//Ministry of Oceans and Fisheries, Republic of Korea/ ; },
abstract = {The emergence of antibiotic resistance in Pseudomonas aeruginosa due to biofilm formation has transformed this opportunistic pathogen into a life-threatening one. Biosynthesized nanoparticles are increasingly being recognized as an effective anti-biofilm strategy to counter P. aeruginosa biofilms. In the present study, gold nanoparticles (AuNPs) were biologically synthesized and stabilized using fucoidan, which is an active compound sourced from brown seaweed. Biosynthesized fucoidan-stabilized AuNPs (F-AuNPs) were subjected to characterization using UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission transmission electron microscopy (FE-TEM), dynamic light scattering (DLS), and energy dispersive X-ray diffraction (EDX). The biosynthesized F-AuNPs were then evaluated for their inhibitory effects on P. aeruginosa bacterial growth, biofilm formation, virulence factor production, and bacterial motility. Overall, the activities of F-AuNPs towards P. aeruginosa were varied depending on their concentration. At minimum inhibitory concentration (MIC) (512 µg/mL) and at concentrations above MIC, F-AuNPs exerted antibacterial activity. In contrast, the sub-inhibitory concentration (sub-MIC) levels of F-AuNPs inhibited biofilm formation without affecting bacterial growth, and eradicated matured biofilm. The minimum biofilm inhibition concentration (MBIC) and minimum biofilm eradication concentration (MBEC) were identified as 128 µg/mL. Furthermore, sub-MICs of F-AuNPs also attenuated the production of several important virulence factors and impaired bacterial swarming, swimming, and twitching motilities. Findings from the present study provide important insights into the potential of F-AuNPs as an effective new drug for controlling P. aeruginosa-biofilm-related infections.},
}
@article {pmid30986604,
year = {2019},
author = {Kowalski, MS and Devlin, TR and di Biase, A and Oleszkiewicz, JA},
title = {Controlling cold temperature partial nitritation in moving bed biofilm reactor.},
journal = {Chemosphere},
volume = {227},
number = {},
pages = {216-224},
doi = {10.1016/j.chemosphere.2019.04.025},
pmid = {30986604},
issn = {1879-1298},
abstract = {Mainstream partial nitritation was studied at 10 °C in a moving bed biofilm reactor treating synthetic wastewater containing both nitrogen (≈40 mg L-1) and organic carbon at COD/N ratio ranging from 1.3 to 2.2. Three different control strategies were investigated to achieve partial nitritation. Initially, biofilm age was controlled by incorporating a media replacement strategy. Next, separately from the media replacement, oxygen limited conditions were investigated and finally pH control was incorporated together with oxygen limitation. Successful partial nitritation was achieved only by combining oxygen limitation with pH control. The average NH4-N concentration was equal to 16.0 ± 1.6 mg L-1 and average NO2-N concentration was equal to 15.7 ± 2.4 mg L-1 during steady state partial nitritation. The average residual NO3-N concentration was equal to 2.6 ± 2.2 mg L-1. The results obtained from this study prove for the first time that partial nitritation can be successfully controlled in a biofilm reactor treating wastewater with low nitrogen concentration, relatively high COD/N ratio and at low temperature. An algorithm for dynamic process control of partial nitritation has been also developed.},
}
@article {pmid30986593,
year = {2019},
author = {Liu, J and Zhou, J and Xu, N and He, A and Xin, F and Ma, J and Fang, Y and Zhang, W and Liu, S and Jiang, M and Dong, W},
title = {Performance evaluation of a lab-scale moving bed biofilm reactor (MBBR) using polyethylene as support material in the treatment of wastewater contaminated with terephthalic acid.},
journal = {Chemosphere},
volume = {227},
number = {},
pages = {117-123},
doi = {10.1016/j.chemosphere.2019.03.186},
pmid = {30986593},
issn = {1879-1298},
abstract = {Untreated terephthalic acid (TPA) wastewaters with high organic loads will cause severe environmental pollution problems. In this study, a lab-scale moving bed biofilm reactor, where biomass of Delftia sp. WL-3 is attached to polypropylene carrier elements, has been tested for TPA bioremediation at 25-27 °C. The system achieved stable operation after a short 15-day start-up period. During the operation period of 65 days, stable chemical oxygen demand (COD) and TPA removal efficiencies of 68% and 76% were maintained with an organic load rate (OLR) and hydraulic retention time of 2.5 kg COD·(m3·d)-1 and 24 h, respectively. In addition, the Scanning Electron Microscope (SEM) showed that high-densities of WL-3 biomass accumulated on the surface of the carrier and formed a rich biofilm, indicating polypropylene carrier can improve the degradation efficiency. On the contrary, the biodegradation ability of stain WL-3 without the polypropylene carrier declined significantly with removal efficiencies of 10% and 15% for COD and TPA. Furthermore, the system exhibited excellent robustness to different OLR and influent matrix ratios, indicating its potential for applications in the treatment of TPA-containment wastewater in the field.},
}
@article {pmid30986518,
year = {2019},
author = {Yoo, Y and Seo, DH and Lee, H and Cho, ES and Song, NE and Nam, TG and Nam, YD and Seo, MJ},
title = {Inhibitory effect of Bacillus velezensis on biofilm formation by Streptococcus mutans.},
journal = {Journal of biotechnology},
volume = {298},
number = {},
pages = {57-63},
doi = {10.1016/j.jbiotec.2019.04.009},
pmid = {30986518},
issn = {1873-4863},
abstract = {Streptococcus mutans plays a key role in the development of dental caries and promotes the formation of oral biofilm produced by glucosyltransferases (GTFs). Bacillus velezensis K68 was isolated from traditional fermented foods and inhibits biofilm formation mediated by S. mutans. Gene amplification results demonstrated that B. velezensis K68 contained genes for the biosynthesis of 1-deoxynojirimycin (1-DNJ), a known GTF expression inhibitor. The presence of the GabT1, Yktc1, and GutB1 genes required for 1-DNJ synthesis in B. velezensis K68 was confirmed. Supernatant from B. velezensis K68 culture medium inhibited biofilm formation by 84% when S. mutans was cultured for 48 h, and inhibited it maximally when 1% glucose was added to the S. mutans culture medium as a GTF substrate. In addition, supernatant from B. velezensis K68 medium containing 3 ppb 1-DNJ decreased S. mutans cell surface hydrophobicity by 79.0 ± 0.8% compared with that of untreated control. The supernatant containing 1-DNJ decreased S. mutans adherence by 99.97% and 98.83% under sugar-dependent and sugar-independent conditions, respectively. S. mutans treated with the supernatant exhibited significantly reduced expression of the essential GTF genes gtfB, gtfC, and gtfD compared to that in the untreated group. Thus, B. velezensis inhibits biofilm formation, adhesion, and GTF gene expression of S. mutans through 1-DNJ production.},
}
@article {pmid30985241,
year = {2019},
author = {Kwiecinski, JM and Jacobsson, G and Horswill, AR and Josefsson, E and Jin, T},
title = {Biofilm formation by Staphylococcus aureus clinical isolates correlates with the infection type.},
journal = {Infectious diseases (London, England)},
volume = {},
number = {},
pages = {1-6},
doi = {10.1080/23744235.2019.1593499},
pmid = {30985241},
issn = {2374-4243},
abstract = {BACKGROUND: Biofilms are involved in many Staphylococcus aureus infections, but relation of biofilm formation and the infection types or the clinical outcomes remain unclear.<br><br>METHODS: We measured biofilm formation, with a microtiter plate assay, of a collection of methicillin-sensitive clinical isolates from 159 invasive S. aureus infections, encompassing all cases occurring within a hospital catchment area during two years, and from additional 49 non-invasive skin infections from the same region. Results were related to available clinical and microbiological documentation.<br><br>RESULTS: Isolates from medical device infections (intravenous line-associated and prosthetic joint infections), as well as isolates from superficial skin infections, were particularly proficient in forming biofilms. No increased biofilm-forming capacity was seen in isolates from endocarditis, osteomyelitis, or other infections. There was also a correlation of biofilm formation with the agr type of the isolates. Thicker biofilms were more resistant to antibiotic treatment in vitro. No correlation between biofilm formation and clinical outcomes was noted.<br><br>CONCLUSIONS: S. aureus isolates from 'classical' biofilm-related infections, but also from superficial skin infections, are especially proficient in forming biofilms. There is, however, no obvious relation of biofilm-forming capacity of isolates and the clinical outcome of the infection, and more studies on this issue are needed.},
}
@article {pmid30984136,
year = {2019},
author = {Bellenberg, S and Huynh, D and Poetsch, A and Sand, W and Vera, M},
title = {Proteomics Reveal Enhanced Oxidative Stress Responses and Metabolic Adaptation in Acidithiobacillus ferrooxidans Biofilm Cells on Pyrite.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {592},
doi = {10.3389/fmicb.2019.00592},
pmid = {30984136},
issn = {1664-302X},
abstract = {Reactive oxygen species (ROS) cause oxidative stress and growth inhibition by inactivation of essential enzymes, DNA and lipid damage in microbial cells. Acid mine drainage (AMD) ecosystems are characterized by low pH values, enhanced levels of metal ions and low species abundance. Furthermore, metal sulfides, such as pyrite and chalcopyrite, generate extracellular ROS upon exposure to acidic water. Consequently, oxidative stress management is especially important in acidophilic leaching microorganisms present in industrial biomining operations, especially when forming biofilms on metal sulfides. Several adaptive mechanisms have been described, but the molecular repertoire of responses upon exposure to pyrite and the presence of ROS are not thoroughly understood in acidophiles. In this study the impact of the addition of H2O2 on iron oxidation activity in Acidithiobacillus ferrooxidans DSM 14882T was investigated. Iron(II)- or sulfur-grown cells showed a higher sensitivity toward H2O2 than pyrite-grown ones. In order to elucidate which molecular responses may be involved, we used shot-gun proteomics and compared proteomes of cells grown with iron(II)-ions against biofilm cells, grown for 5 days in presence of pyrite as sole energy source. In total 1157 proteins were identified. 213 and 207 ones were found to have increased levels in iron(II) ion-grown or pyrite-biofilm cells, respectively. Proteins associated with inorganic sulfur compound (ISC) oxidation were among the latter. In total, 80 proteins involved in ROS degradation, thiol redox regulation, macromolecule repair mechanisms, biosynthesis of antioxidants, as well as metal and oxygen homeostasis were found. 42 of these proteins had no significant changes in abundance, while 30 proteins had increased levels in pyrite-biofilm cells. New insights in ROS mitigation strategies, such as importance of globins for oxygen homeostasis and prevention of unspecific reactions of free oxygen that generate ROS are presented for A. ferrooxidans biofilm cells. Furthermore, proteomic analyses provide insights in adaptations of carbon fixation and oxidative phosphorylation pathways under these two growth conditions.},
}
@article {pmid30983797,
year = {2019},
author = {Karigoudar, RM and Karigoudar, MH and Wavare, SM and Mangalgi, SS},
title = {Detection of biofilm among uropathogenic Escherichia coli and its correlation with antibiotic resistance pattern.},
journal = {Journal of laboratory physicians},
volume = {11},
number = {1},
pages = {17-22},
doi = {10.4103/JLP.JLP_98_18},
pmid = {30983797},
issn = {0974-2727},
abstract = {BACKGROUND: Escherichia coli accounts for 70%-95% of urinary tract infections (UTIs). UTI is a serious health problem with respect to antibiotic resistance and biofilms formation being the prime cause for the antibiotic resistance. Biofilm can restrict the diffusion of substances and binding of antimicrobials. In this context, the present study is aimed to perform in vitro detection of biofilm formation among E. coli strains isolated from urine and to correlate their susceptibility pattern with biofilm formation.<br><br>MATERIALS AND METHODS: A total of 100 E. coli strains isolated from patients suffering from UTI were included in the study. The identification of E. coli was performed by colony morphology, Gram staining, and standard biochemical tests. The detection of biofilm was carried out by Congo Red Agar (CRA) method, tube method (TM), and tissue culture plate (TCP) method. Antimicrobial sensitivity testing was performed by Kirby-Bauer disc diffusion method on Muller-Hinton agar plate.<br><br>RESULTS: Of the 100 E. coli strains, 49 (49%) and 51 (51%) were from catheterized and noncatheterized patients, respectively. Biofilm production was positive by CRA, TM, and TCP method were 49 (49%), 55 (55%), and 69 (69%), respectively. Biofilm producers showed maximum resistance to co-trimoxazole (73.9%), gentamicin (94.2%), and imipenem (11.6%) when compared to nonbiofilm producers. Significant association was seen between resistance to antibiotic and biofilm formation with a P = 0.01 (<0.05).<br><br>CONCLUSION: A greater understanding of biofilm detection in E. coli will help in the development of newer and more effective treatment. The detection of biofilm formation and antibiotic susceptibility pattern helps in choosing the correct antibiotic therapy.},
}
@article {pmid30981136,
year = {2019},
author = {Gandra, TKV and Volcan, D and Kroning, IS and Marini, N and de Oliveira, AC and Bastos, CP and da Silva, WP},
title = {Expression levels of the agr locus and prfA gene during biofilm formation by Listeria monocytogenes on stainless steel and polystyrene during 8 to 48 h of incubation 10 to 37 °C.},
journal = {International journal of food microbiology},
volume = {300},
number = {},
pages = {1-7},
doi = {10.1016/j.ijfoodmicro.2019.03.021},
pmid = {30981136},
issn = {1879-3460},
abstract = {The objective of this study was to compare the gene expression levels of the agr locus and prfA gene during adhesion and biofilm formation by four L. monocytogenes isolates (2 biofilm-forming and 2 non-forming) on stainless steel and polystyrene surfaces at different temperatures (10 °C, 20 °C and 37 °C), and times (8 h, 12 h, 24 h and 48 h). The agrA and prfA genes were expressed at higher levels than the agrBCD genes. The levels of agr locus expression were higher in the biofilm-forming strains, and the greatest difference between biofilm-forming and non-forming isolates was observed for the agrB, agrC and agrD genes. However, no difference in the expression of the prfA gene was seen among the isolates, independent of the biofilm-forming ability. Maximum expression of the agr locus and prfA gene was observed at 37 °C, whereas expression was lowest at 10 °C. The agr locus, and particularly the agrB, agrC and agrD genes, is important in the initial adhesion phase of biofilm production by L. monocytogenes, with this expression independent of prfA. In addition, the agr locus and prfA gene expression levels were strongly influenced by time and temperature.},
}
@article {pmid30981076,
year = {2019},
author = {Sjödin, T},
title = {The pH-dependent effect of cationic and non-ionic delmopinol on planktonic and biofilm bacteria.},
journal = {Archives of oral biology},
volume = {102},
number = {},
pages = {101-105},
doi = {10.1016/j.archoralbio.2019.03.014},
pmid = {30981076},
issn = {1879-1506},
abstract = {OBJECTIVES: The primary purpose was to evaluate the antimicrobial effects of cationic and non-ionic delmopinol on planktonic and biofilm bacteria.<br><br>METHODS: Determination of the minimum inhibitory concentrations on planktonic and biofilm bacteria was performed below and above the pKa-value of delmopinol. Test bacteria were Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa. Comparisons were made with three antimicrobial agents and &quot;quaternary&quot; delmopinol. Synergy testing of delmopinol was determined with serial dilutions of delmopinol with the other compounds in a checkerboard fashion, and the fractional inhibitory concentration index (FIC) was calculated.<br><br>RESULTS: Delmopinol showed minor differences between its MIC- and MBEC-values for all bacterial strains (MBEC/MIC-ratios of 1-2). For the other compounds the difference between their MIC- and MBEC-values were higher and varied considerably between the bacteria. The MIC- and MBEC-concentrations were lower at pH where the non-ionic form of delmopinol dominates. &quot;Quaternary&quot; delmopinol showed the same MIC-concentrations as delmopinol, but needed much higher concentrations to kill biofilm bacteria. Synergy testing showed FIC-indices of 0.5-1.<br><br>CONCLUSIONS: The biofilm penetration of non-ionic delmopinol is better than for cationic delmopinol. Likewise, the cationic test reference samples exerted limited biofilm penetration. The increased efficacy of non-ionic delmopinol is probably due to reduced binding to negative groups in the extracellular matrix of polymeric substances surrounding biofilm bacteria. It is also proposed that the non-ionised form of delmopinol deposits on the biofilm surface. Higher amounts of delmopinol than expected will therefore accumulate. Combinations of delmopinol with other compounds suggests an additive antimicrobial effect.},
}
@article {pmid30980880,
year = {2019},
author = {Liu, L and Zheng, S},
title = {Transcriptional regulation of Yersinia pestis biofilm formation.},
journal = {Microbial pathogenesis},
volume = {131},
number = {},
pages = {212-217},
doi = {10.1016/j.micpath.2019.04.011},
pmid = {30980880},
issn = {1096-1208},
abstract = {Yersinia pestis, the causative agent of plague, is transmitted primarily by infected fleas in nature. Y. pestis can produce biofilms that block flea's proventriculus and promote flea-borne transmission. Transcriptional regulation of Y. pestis biofilm formation plays an important role in the response to complex changes in environments, including temperature, pH, oxidative stress, and restrictive nutrition conditions, and contributes to Y. pestis growth, reproduction, transmission, and pathogenesis. A set of transcriptional regulators involved in Y. pestis biofilm production simultaneously controls a variety of biological functions and physiological pathways. Interactions between these regulators contribute to the development of Y. pestis gene regulatory networks, which are helpful for a quick response to complex environmental changes and better survival. The roles of crucial factors and regulators involved in response to complex environmental signals and Y. pestis biofilm formation as well as the precise gene regulatory networks are discussed in this review, which will give a better understanding of the complicated mechanisms of transcriptional regulation in Y. pestis biofilm formation.},
}
@article {pmid30980362,
year = {2019},
author = {Shahrour, H and Ferrer-Espada, R and Dandache, I and Bárcena-Varela, S and Sánchez-Gómez, S and Chokr, A and Martínez-de-Tejada, G},
title = {AMPs as Anti-biofilm Agents for Human Therapy and Prophylaxis.},
journal = {Advances in experimental medicine and biology},
volume = {1117},
number = {},
pages = {257-279},
doi = {10.1007/978-981-13-3588-4_14},
pmid = {30980362},
issn = {0065-2598},
abstract = {Microbial cells show a strong natural tendency to adhere to surfaces and to colonize them by forming complex communities called biofilms. In this growth mode, biofilm-forming cells encase themselves inside a dense matrix which efficiently protects them against antimicrobial agents and effectors of the immune system. Moreover, at the physiological level, biofilms contain a very heterogeneous cell population including metabolically inactive organisms and persisters, which are highly tolerant to antibiotics. The majority of human infectious diseases are caused by biofilm-forming microorganisms which are responsible for pathologies such as cystic fibrosis, infective endocarditis, pneumonia, wound infections, dental caries, infections of indwelling devices, etc. AMPs are well suited to combat biofilms because of their potent bactericidal activity of broad spectrum (including resting cells and persisters) and their ability to first penetrate and then to disorganize these structures. In addition, AMPs frequently synergize with antimicrobial compounds and were recently reported to repress the molecular pathways leading to biofilm formation. Finally, there is a very active research to develop AMP-containing coatings that can prevent biofilm formation by killing microbial cells on contact or by locally releasing their active principle. In this chapter we will describe these strategies and discuss the perspectives of the use of AMPs as anti-biofilm agents for human therapy and prophylaxis.},
}
@article {pmid30979839,
year = {2019},
author = {Pandin, C and Darsonval, M and Mayeur, C and Le Coq, D and Aymerich, S and Briandet, R},
title = {Biofilm formation and synthesis of antimicrobial compounds by the biocontrol agent Bacillus velezensis QST713 in Agaricus bisporus compost micromodel.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.00327-19},
pmid = {30979839},
issn = {1098-5336},
abstract = {Bacillus velezensis QST713 is widely used as a biological control agent for crop protection and disease suppression. This strain is used industrially in France for the protection of Agaricus bisporus against Trichoderma aggressivum f. europaeum, the green mould disease. The efficacy of this biocontrol process had been evaluated in a previous report, yet the mode of its action has not been explored under production conditions. In order to decipher the underlying biocontrol mechanisms for effective biofilm formation of strain QST713 in the compost and for the involvement of antimicrobial compounds, we developed a simplified micromodel for the culture of A. bisporus during its early culture cycle. By using this micromodel system, we studied the transcriptional response of strain QST713 in the presence or absence of A. bisporus and/or T. aggressivum in axenic industrial compost. We report an over-expression of several genes of the biocontrol agent involved in biofilm formation in the compost compared to expression during growth in broth compost extract, either in the exponential growth phase (epsC, blsA and tapA genes) or in the stationary growth phase (tapA gene), while a gene encoding a flagellar protein (hag) was under-expressed. We also report an over-expression of Bacillus velezensis QST713 genes related to surfactin (srfAA) and fengycin (fenA) production in the presence of the fungal pathogen in the compost.ImportanceBiocontrol agents are increasingly used to replace chemical pesticides to prevent crop diseases. In the button mushroom field in France, the use of Bacillus velezensis QST713 as a biocontrol agent against the green mold Trichoderma aggressivum, has been shown to be efficient. However, the biocontrol mechanisms effective in the pathosystem Agaricus bisporus/Trichoderma aggressivum/Bacillus velezensis QST713 are still unknown. Our paper focuses on the exploration of the bioprotection mechanisms of the biocontrol agent Bacillus velezensis QST713 during the culture of the button mushroom (Agaricus bisporus) in a micromodel culture system to study the specific response of strain QST713 in the presence of T. aggressivum and/or A. bisporus.},
}
@article {pmid30978919,
year = {2019},
author = {Farkash, Y and Feldman, M and Ginsburg, I and Steinberg, D and Shalish, M},
title = {Polyphenols Inhibit Candida albicans and Streptococcus mutans Biofilm Formation.},
journal = {Dentistry journal},
volume = {7},
number = {2},
pages = {},
doi = {10.3390/dj7020042},
pmid = {30978919},
issn = {2304-6767},
abstract = {Background:Streptococcus mutans (S. mutans) and Candida albicans (C. albicans) are two major contributors to dental caries. They have a symbiotic relationship, allowing them to create an enhanced biofilm. Our goal was to examine whether two natural polyphenols (Padma hepaten (PH) and a polyphenol extraction from green tea (PPFGT)) could inhibit the caries-inducing properties of S. mutans and C. albicans. Methods: Co-species biofilms of S. mutans and C. albicans were grown in the presence of PH and PPFGT. Biofilm formation was tested spectrophotometrically. Exopolysaccharides (EPS) secretion was quantified using confocal scanning laser microscopy. Biofilm development was also tested on orthodontic surfaces (Essix) to assess biofilm inhibition ability on such an orthodontic appliance. Results: PPFGT and PH dose-dependently inhibited biofilm formation without affecting the planktonic growth. We found a significant reduction in biofilm total biomass using 0.625 mg/mL PPFGT and 0.16 mg/mL PH. A concentration of 0.31 mg/mL PPFGT and 0.16 mg/mL PH inhibited the total cell growth by 54% and EPS secretion by 81%. A reduction in biofilm formation and EPS secretion was also observed on orthodontic PVC surfaces. Conclusions: The polyphenolic extractions PPFGT and PH have an inhibitory effect on S. mutans and C. albicans biofilm formation and EPS secretion.},
}
@article {pmid30976947,
year = {2019},
author = {Lee, YS and Park, W},
title = {Enhanced calcium carbonate-biofilm complex formation by alkali-generating Lysinibacillus boronitolerans YS11 and alkaliphilic Bacillus sp. AK13.},
journal = {AMB Express},
volume = {9},
number = {1},
pages = {49},
doi = {10.1186/s13568-019-0773-x},
pmid = {30976947},
issn = {2191-0855},
support = {19SCIP-B103706-05//Ministry of Land, Infrastructure and Transport, Republic of Korea/ ; },
abstract = {Microbially induced calcium carbonate (CaCO3) precipitation (MICP) is a process where microbes induce condition favorable for CaCO3 formation through metabolic activities by increasing the pH or carbonate ions when calcium is near. The molecular and ecological basis of CaCO3 precipitating (CCP) bacteria has been poorly illuminated. Here, we showed that increased pH levels by deamination of amino acids is a driving force toward MICP using alkalitolerant Lysinibacillus boronitolerans YS11 as a model species of non-ureolytic CCP bacteria. This alkaline generation also facilitates the growth of neighboring alkaliphilic Bacillus sp. AK13, which could alter characteristics of MICP by changing the size and shape of CaCO3 minerals. Furthermore, we showed CaCO3 that precipitates earlier in an experiment modifies membrane rigidity of YS11 strain via upregulation of branched chain fatty acid synthesis. This work closely examines MICP conditions by deamination and the effect of MICP on cell membrane rigidity and crystal formation for the first time.},
}
@article {pmid30975483,
year = {2019},
author = {Llama-Palacios, A and Sánchez, MC and Díaz, LA and Cabal, B and Suárez, M and Moya, JS and Torrecillas, R and Figuero, E and Sanz, M and Herrera, D},
title = {In vitro biofilm formation on different ceramic biomaterial surfaces: Coating with two bactericidal glasses.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.dental.2019.03.003},
pmid = {30975483},
issn = {1879-0097},
abstract = {OBJECTIVES: To compare biofilm formation on the surface of different ceramic biomaterials to be used in implant dentistry.<br><br>METHODS: In vitro biofilm formation was investigated from mixtures of standard reference strains of Streptococcus oralis, Veillonella parvula, Actinomyces naeslundii, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Sterile ceramic calcium hydroxyapatite discs (HA) as control, sterile Al2O3/Ce-TZP nanocomposite sandblasted discs (material A1) and sterile Al2O3/Ce-TZP nanocomposite sandblasted discs and coated with two types of antimicrobial glasses (materials A2 and A3) were used. Biofilms were grown on the four surfaces and evaluated after 12, 24, 48 and 72 h of incubation. Biofilms were examined by confocal laser scanning microscopy (CLSM). In addition, counts of live bacterial cells of the target species A. actinomycetemcomitans, F. nucleatum and P. gingivalis were calculated by quantitative polymerase chain reaction (qPCR) combined with propidium monoazide (PMA). For data analysis, bacterial counts were compared with a multivariate general lineal model.<br><br>RESULTS: Using CLSM, cell vitality decreased in A2 and A3. With qPCR-PMA, significant differences in vitality were observed forA. actinomycetemcomitans in A3 after 48 and 72 h of incubation. With respect to the development of the biofilms, a significant increase in counts on HA and materials A1 and A2 was observed for A. actinomycetemcomitans and F. nucleatum. Conversely, for P. gingivalis, no differences were found for HA and materials A1 and A2.<br><br>SIGNIFICANCE: Differences in biofilm formation were detected among the different tested materials. The ceramic material A3 has an effect on the vitality of A. actinomycetemcomitans growing in an in vitro biofilm model.},
}
@article {pmid30972606,
year = {2019},
author = {El-Banna, T and Abd El-Aziz, A and Sonbol, F and El-Ekhnawy, E},
title = {Adaptation of Pseudomonas aeruginosa clinical isolates to benzalkonium chloride retards its growth and enhances biofilm production.},
journal = {Molecular biology reports},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11033-019-04806-7},
pmid = {30972606},
issn = {1573-4978},
abstract = {The increasing percentage of Pseudomonas aeruginosa strains that are resistant to multiple antibiotics is a global problem. The exposure of P. aeruginosa isolates to repeated sub lethal concentrations of biocides in hospitals and communities may be one of the causes leading to increased antibiotic resistance. Benzalkonium chloride (BAC) is widely used as disinfectant and preservative. This study investigated the effect of exposure of P. aeruginosa clinical isolates to sub lethal concentrations of BAC on their antibiotic resistance, growth process and biofilm formation. The collected 43 P. aeruginosa clinical isolates were daily subjected to increasing sub lethal concentrations of BAC. The effect of adaptation on antibiotic resistance, growth process, cell surface hydrophobicity and biofilm formation of P. aeruginosa isolates were examined. Interestingly, Most P. aeruginosa isolates adapted to BAC showed an increase in antibiotic resistance and 66% of the isolates showed retardation of growth, 63% showed increased cell surface hydrophobicity and 23.5% exhibited enhanced biofilm formation by crystal violet assay. To define whether the effect of BAC adaptation on biofilm production was manifested at the transcriptional level, quantitative RT-PCR was used. We found that 60% of the tested isolates showed overexpression of ndvB biofilm gene. More efforts are required to diminish the increasing use of BAC to avoid bacterial adaptation to this biocide with subsequent retardation of growth and enhanced biofilm formation which could lead to antibiotic resistance and treatment failure of infections caused by this opportunistic pathogen.},
}
@article {pmid30972161,
year = {2019},
author = {Du, Z and Huang, Y and Chen, Y and Chen, Y},
title = {Combination effects of baicalin with levofloxacin against biofilm-related infections.},
journal = {American journal of translational research},
volume = {11},
number = {3},
pages = {1270-1281},
pmid = {30972161},
issn = {1943-8141},
abstract = {It is important to improve the existing techniques and develop new strategies to prevent bacterial biofilm formation. In this in vitro study, biofilms were established by a clinically isolated strain of Staphylococcus aureus 17546 (t037). Different concentrations of baicalin were added to 3- and 7-day biofilms. Based on colony counts and quantitative analysis of the biomass, sub-minimum inhibitory concentrations (sub-MICs) (1024, 512 or 256 μg/mL) of baicalin clearly decreased the number of bacterial colonies and biomass in vitro. Fluorescence microscopy revealed that sub-MICs (1024, 512, or 256 μg/mL) of baicalin inhibited bacterial adherence to the carrier surface and decreased polysaccharide production. Moreover, baicalin disrupted biofilms and exhibited synergistic effects with levofloxacin. Virulence factors were assessed by western blotting and real-time quantitative polymerase chain reaction, confirming that staphylococcal enterotoxin A, α-haemolysin and coagulase production decreased after baicalin treatment. Additionally, baicalin increased production of thermonuclease in S. aureus, and baicalin at 1024 and 512 μg/mL downregulated agrA expression. Based on these findings, the combination of baicalin with levofloxacin might be a new, feasible strategy for treating S. aureus biofilm-related infections. Baicalin may serve as a new inhibitor that modulates S. aureus virulence factors.},
}
@article {pmid30971289,
year = {2019},
author = {Declercq, AM and Cai, W and Naranjo, E and Thongda, W and Eeckhaut, V and Bauwens, E and Arias, C and De La Fuente, L and Beck, BH and Lange, MD and Peatman, E and Haesebrouck, F and Aerts, J and Decostere, A},
title = {Evidence that the stress hormone cortisol regulates biofilm formation differently among Flavobacterium columnare isolates.},
journal = {Veterinary research},
volume = {50},
number = {1},
pages = {24},
doi = {10.1186/s13567-019-0641-3},
pmid = {30971289},
issn = {1297-9716},
support = {BOF.PDO.2015.0020.01//Bijzonder Onderzoeksfonds/ ; V423316N//Fonds Wetenschappelijk Onderzoek/ ; },
mesh = {Animals ; Bacterial Adhesion/*genetics ; Biofilms/drug effects/*growth &amp; development ; Carps/microbiology ; Dose-Response Relationship, Drug ; Flavobacterium/drug effects/genetics/pathogenicity/*physiology ; *Gene Expression ; Genes, Bacterial/*physiology ; Hydrocortisone/administration &amp; dosage/*metabolism ; Lab-On-A-Chip Devices/veterinary ; Plankton/drug effects/growth &amp; development ; Virulence ; },
abstract = {The impact of cortisol on Flavobacterium columnare biofilm formation was explored. Firstly, the dynamics of biofilm formation by one highly (HV) and one low virulent (LV) F. columnare isolate with and without the stress hormone cortisol under microfluidic flow conditions was characterized. This to confirm that F. columnare cells could form biofilm under cortisol supplementation, and to compare the temporal and structural differences between different treatment groups. One trial revealed that in both isolates cell aggregates resembling biofilms occurred within 7-h post-inoculation. Consequently, cell clusters were sloughed away, followed by a rebuilding of bacterial cell aggregates, suggestive for a high spreading capacity. While the HV isolate revealed cell aggregates formed upstream at all time-points, for the LV isolate this was only seen upon cortisol supplementation. Secondly, the transcriptional effect of genes (gldK, gldL, gldM, gldN, sprA, sprE, sprT, and porV) belonging to the Type IX secretion system involved in gliding motility was investigated in planktonic and biofilm cells of a HV and LV isolate to which no, a low (LD) or high (HD) dose of cortisol was added. Significantly lower expression of gliding genes gldK, gldL, gldM and gldN, and of protein secretion regulator porV was seen in the LV isolate planktonic cells supplemented with a HD-cortisol. The LV isolate biofilm cells treated with the HD-cortisol showed a significant upregulation of sprT, encoding mobile surface adhesion important in bacterial colonization. This is the first evidence for the co-regulatory effect of cortisol on biofilm formation and F. columnare gliding gene expression.},
}
@article {pmid30970480,
year = {2019},
author = {Jepsen, R and He, K and Blaney, L and Swan, C},
title = {Effects of antimicrobial exposure on detrital biofilm metabolism in urban and rural stream environments.},
journal = {The Science of the total environment},
volume = {666},
number = {},
pages = {1151-1160},
doi = {10.1016/j.scitotenv.2019.02.254},
pmid = {30970480},
issn = {1879-1026},
abstract = {The occurrence of antimicrobials and other pharmaceuticals in streams is increasingly being reported, yet the impacts of these contaminants of emerging concern on aquatic ecosystems are relatively unknown. Bacteria and fungi are vital components of stream environments and, therefore, exposure to antimicrobials may have important consequences for ecosystem services, such as carbon cycling. The objective of this study was to investigate how two antimicrobials, ciprofloxacin and climbazole, impact detrital biofilm metabolism in urban and rural streams. To establish baseline conditions, the biological oxygen demand (BOD) of red maple (Acer rubrum) biofilms was measured in one urban and one rural stream. In mesocosm studies, the BOD of biofilms on single- and mixed-species leaf litter from the same sites was measured after exposure to 10 μg/L of the antimicrobials, both in combination and individually. The presence of ciprofloxacin and climbazole did not affect BOD compared to the controls at the urban site, although significant differences were identified for select treatments at the rural site. In addition, the BOD of mixed-leaf biofilms was not significantly different from that of single species litter after exposure. Overall, exposure to 10 μg/L of the antimicrobials did not significantly impact community-level carbon processing by the leaf biofilms, and leaf mixtures did not result in increased biofilm BOD compared to single species leaves. The outcomes of this work demonstrate a need for further research for the understanding the effects of antimicrobials on rural streams to prevent unintended consequences to ecological processes and biota from future development, leaking septic systems, and wastewater spills.},
}
@article {pmid30969774,
year = {2019},
author = {Liébana, R and Modin, O and Persson, F and Szabó, E and Hermansson, M and Wilén, BM},
title = {Combined Deterministic and Stochastic Processes Control Microbial Succession in Replicate Granular Biofilm Reactors.},
journal = {Environmental science &amp; technology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.est.8b06669},
pmid = {30969774},
issn = {1520-5851},
abstract = {Granular sludge is an efficient and compact biofilm process for wastewater treatment. However, the ecological factors involved in microbial community assembly during the granular biofilm formation are poorly understood, and little is known about the reproducibility of the process. Here, three replicate bioreactors were used to investigate microbial succession during the formation of granular biofilms. We identified three successional phases. During the initial phase, the successional turnover was high and α-diversity decreased as a result of the selection of taxa adapted to grow on acetate and form aggregates. Despite these dynamic changes, the microbial communities in the replicate reactors were similar. The second successional phase occurred when the settling time was rapidly decreased to selectively retain granules in the reactors. The influence of stochasticity on succession increased and new niches were created as granules emerged, resulting in temporarily increased α-diversity. The third successional phase occurred when the settling time was kept stable and granules dominated the biomass. Turnover was low, and selection resulted in the same abundant taxa in the reactors, but drift, which mostly affected low-abundant community members, caused the community in one reactor to diverge from the other two. Even so, performance was stable and similar between reactors.},
}
@article {pmid30967851,
year = {2019},
author = {Rojo-Molinero, E and Macià, MD and Oliver, A},
title = {Social Behavior of Antibiotic Resistant Mutants Within Pseudomonas aeruginosa Biofilm Communities.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {570},
doi = {10.3389/fmicb.2019.00570},
pmid = {30967851},
issn = {1664-302X},
abstract = {The complex spatial structure and the heterogeneity within biofilms lead to the emergence of specific social behaviors. However, the impact of resistant mutants within bacterial communities is still mostly unknown. Thus, we determined whether antibiotic resistant mutants display selfish or altruistic behaviors in mixed Pseudomonas aeruginosa biofilms exposed to antibiotics. ECFP-tagged P. aeruginosa strain PAO1 and its EYFP-tagged derivatives hyperproducing the β-lactamase AmpC or the efflux pump MexAB-OprM were used to develop single or mixed biofilms. Mature biofilms were challenged with different concentrations of β-lactams to monitor biofilm structural dynamics, using confocal laser scanning microscopy (CLSM), and population dynamics, through enumeration of viable cells. While exposure of single wild-type PAO1 biofilms to β-lactams lead to a major reduction in bacterial load, it had little effect on biofilms formed by the resistant mutants. However, the most reveling finding was that bacterial load of wild-type PAO1 was significantly increased when growing in mixed biofilms compared to single biofilms. In agreement with CFU enumeration data, CLSM images revealed the amplification of the resistant mutants and their protection of susceptible populations. These findings show that mutants expressing diverse resistance mechanisms, including β-lactamases, but also, as evidenced for the first time, efflux pumps, protect the whole biofilm community, preserving susceptible populations from the effect of antibiotics. Thus, these results are a step forward to understanding antibiotic resistance dynamics in biofilms, as well as the population biology of bacterial pathogens in chronic infections, where the coexistence of susceptible and resistant variants is a hallmark.},
}
@article {pmid30965175,
year = {2019},
author = {Tombola, R and Buttiglieri, G and Auset, M and Gonzalez-Olmos, R},
title = {Recycled corrugated wire hose cover as biological carriers for greywater treatment in a sequential batch biofilm reactor.},
journal = {Journal of environmental management},
volume = {240},
number = {},
pages = {475-484},
doi = {10.1016/j.jenvman.2019.02.116},
pmid = {30965175},
issn = {1095-8630},
abstract = {Greywater treatment and reuse can be considered a promising option, in particular in water scarcity affected areas. In this work a waste material, namely recycled corrugated wire hose cover, was applied as an alternative and cheap carrier in a sequencing batch biofilm reactor (SBBR) for greywater treatment. The bioreactor performance was studied in terms of organic matter, nitrogen and micropollutant removal. Four operational stages were investigated: i) inoculation of the carriers; ii) greywater treatment with suspended biomass; iii) synthetic and iv) real greywater treatment with inoculated carriers in the SBBR. The SBBR could treat real greywater showing high removal efficiencies for COD (86.5 ± 5.8%), ammonium (98.4 ± 1.4%) and total nitrogen (71.4 ± 8.2%). The obtained efficiencies were similar to the ones obtained with commercial carriers and to other treatments such as MBBR or MBR. In terms of micropollutants, 7 out of 13 detected micropollutants were highly removed (efficiency higher than 85%) while 5 of them (ofloxacin, metoprolol acid, venlafaxine, iopromide and hydrochlorothiazide) were found to be highly recalcitrant to the treatment.},
}
@article {pmid30965160,
year = {2019},
author = {Jafari, M and Derlon, N and Desmond, P and van Loosdrecht, MCM and Morgenroth, E and Picioreanu, C},
title = {Biofilm compressibility in ultrafiltration: A relation between biofilm morphology, mechanics and hydraulic resistance.},
journal = {Water research},
volume = {157},
number = {},
pages = {335-345},
doi = {10.1016/j.watres.2019.03.073},
pmid = {30965160},
issn = {1879-2448},
abstract = {Poroelastic fluid-structure interaction models were coupled to experimental data to determine the effects of biofilm spatial distribution of mechanical and hydraulic properties on the biofilm hydraulic resistance and compressibility in membrane filtration processes. Biofilms were cultivated on ultrafiltration membranes for 20 and 30 days under high (0.28 bar) and low (0.06 bar) transmembrane pressure (TMP), in dead-end filtration mode. Subsequently, biofilms were subjected to a compression/relaxation cycles by step-wise TMP changes. Structural deformation of biofilms during compression was observed in-situ using optical coherence tomography. Experimental results show that the observed increase in the biofilm hydraulic resistance during compression is not necessarily accompanied by a detectable biofilm thickness reduction. A dual-layer biofilm model with a dense base and porous top layer could explain these observed results. Because porosity controls indirectly the mechanical response of biofilms under compression, results could be described without assuming a gradient in mechanical properties within the biofilm. The biofilm surface roughness did not significantly influence the water flux in this study. However, the fraction of biofilm base layer directly exposed to bulk liquid could be a good indicator in the determination of water flux. The main implications of this study for the design and operation of low-pressure membrane systems (e.g., MF and UF with fouling layer being the main filtration resistance) lays in the selection of favorable operational TMP and biofilm morphology.},
}
@article {pmid30965147,
year = {2019},
author = {Bal, FA and Ozkocak, I and Cadirci, BH and Karaarslan, ES and Cakdinleyen, M and Agaccioglu, M},
title = {Effects of Photodynamic Therapy with Indocyanine Green on Streptococcus Mutans Biofilm.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.04.005},
pmid = {30965147},
issn = {1873-1597},
abstract = {BACKGROUND: The current procedures for treating tooth decay are not always guaranteed to successfully remove all microorganisms which cause disease. For elimination of bacteria and prevention of their effects, different methods are recommended, such as antibacterial materials and cavity disinfectants. The aim of this study was to compare the antibacterial activity of the photodynamic therapy (PDT) using diode laser with indocyanin green (ICG) on Streptococcus (S.) mutans biofilm with conventional methods.<br><br>METHODS: Ninety human molars were divided into 9 groups: negative control, positive control, CHX, NaOCl, gaseous ozone, erbium (Er):YAG laser, diode laser, and indocyanin green/ICG, and PDT. Cavities were then cut into the teeth (2 per tooth, 20 cavities per group) and sterilized. For all of the groups, with the exception of the negative control group, 105 CFU/mL of the active S. mutans culture were inoculated into the cavities and then incubated at 37 °C for 72 h. Then, dentin chips (25 ± 5 mg) were collected from cavity walls and spread on Mueller-Hinton agar media after decimal dilution. The colonies were counted after incubation at 37 °C for 24 h.<br><br>RESULTS: All the treatments significantly reduced the number of S. mutans compared with the positive control group (p < 0.05). The antimicrobial effectiveness of CHX, NaOCl, ozone, PDT, Er:YAG laser, and diode laser groups were similar. The lowest bacterial reduction was observed in the ICGgroup.<br><br>CONCLUSIONS: This work concludes that PDT using diode laser with ICG may be suggested on the cavity disinfection after caries excavation as an alternative to conventional methods.},
}
@article {pmid30965089,
year = {2019},
author = {Souza Dos Santos, B and Bezerra Filho, CM and Alves do Nascimento Junior, JA and Brust, FR and Bezerra-Silva, PC and Lino da Rocha, SK and Krogfelt, KA and Maria do Amaral Ferraz Navarro, D and Tereza Dos Santos Correia, M and Napoleão, TH and Nascimento da Silva, LC and Macedo, AJ and Vanusa da Silva, M and Guedes Paiva, PM},
title = {Anti-staphylococcal activity of Syagrus coronata essential oil: Biofilm eradication and in vivo action on Galleria mellonela infection model.},
journal = {Microbial pathogenesis},
volume = {131},
number = {},
pages = {150-157},
doi = {10.1016/j.micpath.2019.04.009},
pmid = {30965089},
issn = {1096-1208},
abstract = {In this study, essential oil extracted from Syagrus coronata seeds (SCEO) was evaluated for antibacterial and antibiofilm activities against Staphylococcus aureus; in addition, Galleria mellonella model was used as an in vivo infection model. SCEO was mainly composed by fatty acids (89.79%) and sesquiterpenes (8.5%). The major components were octanoic acid, dodecanoic acid, decanoic acid and γ-eudesmol. SCEO showed bactericidal activity (minimal bactericidal concentration from 312 to 1250 μg/mL) against all tested S. aureus clinical isolates, which showed distinct biofilm-forming and multiple drug resistance phenotypes. SCEO weakly reduced biomass but remarkably decreased cell viability in pre-formed biofilms of S. aureus isolate UFPEDA-02 (ATCC-6538). Electron microscopy analysis showed that SCEO treatments decreased the number of bacterial cells (causing structural alterations) and lead to loss of the roughness in the multiple layers of the three-dimensional biofilm structure. In addition, overproduction of exopolymeric matrix was observed. SCEO at 31.2 mg/kg improved the survival of G. mellonela larvae inoculated with UFPEDA-02 isolate and reduced the bacterial load in hemolymph and melanization. In conclusion, SCEO is an antibacterial agent against S. aureus strains with different resistance phenotypes and able to disturb biofilm architecture. Our results show SCEO as a potential candidate to drug development.},
}
@article {pmid30964013,
year = {2018},
author = {Pattnaik, S and Barik, S and Muralitharan, G and Busi, S},
title = {Ferulic acid encapsulated chitosan-tripolyphosphate nanoparticles attenuate quorum sensing regulated virulence and biofilm formation in Pseudomonas aeruginosa PAO1.},
journal = {IET nanobiotechnology},
volume = {12},
number = {8},
pages = {1056-1061},
doi = {10.1049/iet-nbt.2018.5114},
pmid = {30964013},
issn = {1751-875X},
abstract = {Pseudomonas aeruginosa is an opportunistic nosocomial pathogenic microorganism causing majority of acute hospital-acquired infections and poses a serious public health concern. The persistence of bacterial infection can be attributed to the highly synchronised cell-to-cell communication phenomenon, quorum sensing (QS) which regulates the expression of a number of virulence factors and biofilm formation which eventually imparts resistance to the conventional antimicrobial therapy. In this study, the anti-quorum sensing and anti-biofilm potential of ferulic acid encapsulated chitosan-tripolyphosphate nanoparticles (FANPs) was investigated against P. aeruginosa PAO1 and compared with native ferulic acid. Dynamic light scattering and transmission electron microscopic analysis confirmed the synthesis of FANPs with mean diameter of 215.55 nm. FANPs showed significant anti-quorum sensing activity by downregulating QS-regulated virulence factors. In addition, FANPs also significantly attenuate the swimming and swarming motility of P. aeruginosa PAO1. The anti-biofilm efficacy of FANPs as compared to native ferulic acid was established by light and confocal laser scanning microscopic analysis. The promising results of FANPs in attenuating QS highlighted the slow and sustained release of ferulic acid at the target sites with greater efficacy suggesting its application towards the development of anti-infective agents.},
}
@article {pmid30963965,
year = {2019},
author = {Francolini, I and Piozzi, A},
title = {Role of antioxidant molecules and polymers in prevention of bacterial growth and biofilm formation.},
journal = {Current medicinal chemistry},
volume = {},
number = {},
pages = {},
doi = {10.2174/0929867326666190409120409},
pmid = {30963965},
issn = {1875-533X},
abstract = {BACKGROUND: Antioxidants are multifaceted molecules playing a crucial role in several cellular functions. There is by now a well-established knowledge about their involvement in numerous processes associated with aging, including vascular damage, neurodegenerative diseases and cancer. An emerging area of application has been lately identified for these compounds in relation to the recent findings indicating their ability to affect biofilm formation by some microbial pathogens, including Staphylococcus aureus, Streptococcus mutans, and Pseudomonas aeruginosa.<br><br>METHODS: A structured search of bibliographic databases for peer-reviewed research literature was performed using a focused review question. The quality of retrieved papers was appraised using standard tools.<br><br>RESULTS: One hundred sixty five papers extracted from pubmed database and published in the last fifteen years were included in this review focused on the assessment of the antimicrobial and anti-biofilm activity of antioxidant compounds, including vitamins, flavonoids, non-flavonoid polyphenols, and antioxidant polymers. Mechanisms of action of some important antioxidant compounds, especially for vitamin C and phenolic acids, were identified.<br><br>CONCLUSIONS: The findings of this review confirm the potential benefits of the use of natural antioxidants as antimicrobial/antibiofilm compounds. Generally, gram-positive bacteria were found to be more sensitive to antioxidants than gram-negatives. Antioxidant polymeric systems have been also developed mainly derived from functionalization of polysaccharides with antioxidant molecules. The application of such systems in clinics may permit to overcome some issues related to the systemic delivery of antioxidants, such as poor absorption, loss of bioactivity, and limited half-life. However, investigations focused on the study of antibiofilm activity of antioxidant polymers are still very limited in number and therefore they are strongly encouraged in order to lay the foundations for application of antioxidant polymers in treatment of biofilm-based infections.},
}
@article {pmid30962840,
year = {2019},
author = {Naumenko, ZS and Silanteva, TA and Ermakov, AM and Godovykh, NV and Klushin, NM},
title = {Challenging Diagnostics of Biofilm Associated Periprosthetic Infection in Immunocompromised Patient: A Clinical Case.},
journal = {Open access Macedonian journal of medical sciences},
volume = {7},
number = {5},
pages = {786-790},
doi = {10.3889/oamjms.2019.180},
pmid = {30962840},
issn = {1857-9655},
abstract = {BACKGROUND: Periprosthetic joint infection (PJI) is a devastating complication of joint arthroplasty. The identification of microorganisms in biofilm-related PJI is challenging yet significant stage of the treatment process. Medical microbiology methods, such as pure culture isolation, remain the gold standard. However, the error rate of classical methods may vary from 10% to as high as 42% due to the inability to detect bacteria growing within biofilms. Other methods of detection are being explored to improve the management of PJI.<br><br>AIM: Accurate identification of PJI contributing microorganisms in a patient with acute postoperative PJI after total hip joint arthroplasty and systemic lupus erythematosus in anamnesis.<br><br>METHODS: We used microbial culture methods followed by scanning electron microscopy (SEM).<br><br>RESULTS: Perioperative an intraoperative cultural analysis of 8 different culture samples of tissue and prosthetic origin was insufficient for bacterial or fungal detection. Scanning electron microscopy revealed detailed biofilm visualisation on the surface of the prosthetic component. The biofilm exterior was composed of microbial clusters made of 10 or more cells with either pear- or bottle-shaped morphology, 3-6 mcm in length and 1.5-3 mcm in diameter. Rod-shaped microorganisms of 0.7-1 mcm length and up to 0.5 mcm in diameter were found adjacent to these clusters.<br><br>CONCLUSION: Additional methods for PJI agents' detection are time-and cost-effective in the case of the challenging diagnostics of biofilm-related PJI, particularly in immunocompromised patients. Using combined diagnostic approaches increases the accuracy of detection, justifies treatment strategies and improves clinical outcomes.},
}
@article {pmid30962351,
year = {2019},
author = {Neiger, MR and González, JF and Gonzalez-Escobedo, G and Kuck, H and White, P and Gunn, JS},
title = {Pathoadaptive alteration of Salmonella biofilm formation in response to the gallbladder environment.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00774-18},
pmid = {30962351},
issn = {1098-5530},
abstract = {Typhoid fever, a human-specific disease, is primarily caused by the pathogen Salmonella enterica serovar Typhi (S Typhi). It is estimated that 3-5% of people infected with typhoid fever become chronic carriers. Studies have demonstrated that a mechanism of chronic carriage involves biofilm formation on gallstone surfaces. In the course of a previous study using a chronic carriage mouse model, a S. Typhimurium isolate was recovered from a mouse gallstone that exhibited a 2-fold increase in biofilm formation over the wild type. In order to identify the gene(s) responsible for the phenotype, the genomic sequence of this isolate and others were determined and compared. These sequences identified SNPs in 14 genes. Mutations in the most promising candidates, envZ and rcsB, were created but neither showed increased biofilm-forming ability separately or in combination. The hyper-biofilm isolate did however, present variations in cellular appendages observable using different techniques and a preferential binding to cholesterol. The isolate was also examined for systemic virulence and the ability to colonize the gallbladder/gallstones in a mouse model of chronic infection, demonstrating a systemic virulence defect and decreased gallbladder/gallstone colonization Finally, to determine if the appearance of hyper-biofilm isolates could be replicated in vitro and if this was a common event, wild type Salmonella was grown long-term in vitro in gallbladder-mimicking conditions, resulting in a high proportion of isolates that replicated the hyper-biofilm phenotype of the original isolate. Thus, Salmonella acquire random mutations in the gallbladder/gallbladder-simulating conditions that may aid persistence but negatively affect systemic virulence.IMPORTANCEChronic carriers are the main reservoirs for the spread of typhoid fever in endemic regions. Salmonella Typhi forms biofilms on gallstones in order to persist. A strain with enhanced biofilm-forming ability was recovered after a nine-month chronic carriage mouse study. After sequencing this strain and recreating some of the mutations we could not duplicate the phenotype. The isolate did show a difference in flagella, a preference to bind to cholesterol and a systemic virulence defect. Finally, gallbladder conditions were simulated in vitro After 60 days, there was a 4.5-fold increase in hyper-biofilm isolates when a gallstone was present. These results indicate that Salmonella can undergo genetic changes that improve persistence in gallbladder albeit at the cost of decreased virulence.},
}
@article {pmid30961703,
year = {2019},
author = {Lu, R and Sun, J and Osei-Adjei, G and Zhang, Y and Huang, X},
title = {The Periplasmic Chaperone SurA Affects Motility and Biofilm Formation via the RcsCDB Pathway in Salmonella enterica Serovar Typhi.},
journal = {Journal of nanoscience and nanotechnology},
volume = {19},
number = {9},
pages = {5503-5509},
doi = {10.1166/jnn.2019.16503},
pmid = {30961703},
issn = {1533-4880},
abstract = {SurA, a periplasmic chaperone, is a key factor in the biogenesis of β-barrel outer membrane proteins (OMPs). It is also associated with virulence, invasion and biofilm formation in Escherichia and Salmonella species. To investigate whether SurA affects bacterial motility and biofilm formation in Salmonella enterica serovar Typhi, we prepared a surA deleted mutant. Motility assay and quantitative real-time PCR (qRT-PCR) indicated that surA deletion reduced swimming motility and decreased flagellar gene expression, respectively. β-galactosidase assay and qRT-PCR further showed that surA deletion also activated the RcsCDB pathway, which we verified affected motility. We also examined the effects of the surA deletion on biofilm formation and established that the surA mutant exhibited significantly reduced ability to form biofilms compared with the wild-type. From our findings, we proposed that the periplasmic chaperone, SurA, affects flagella expression via the RcsCDB pathway thereby influencing biofilm formation in Salmonella enterica serovar Typhi. Collectively, these studies confirmed a new physiological role for SurA in Salmonella enterica serovar Typhi.},
}
@article {pmid30960145,
year = {2019},
author = {Lang, Y and Sun, Y and Yu, M and Ji, Y and Wang, L and Zhang, Z},
title = {Differential Colonization Dynamics of Marine Biofilm-Forming Eukaryotic Microbes on Different Protective Coating Materials.},
journal = {Polymers},
volume = {11},
number = {1},
pages = {},
doi = {10.3390/polym11010161},
pmid = {30960145},
issn = {2073-4360},
support = {2017M621294//Chinese Postdoctoral Science Foundation/ ; 41418083//the Fundamental Operating Expenses of the Central Universities/ ; 2017BSH002,2017BSH003//the Supporting Program of the Postdoctoral Research at the Harbin University of Commerce/ ; 17XN011, 17XN010//the Training Program of the Young Creative Talents at the Harbin University of Commerce/ ; 2016GSF115022//the Key research and development plan of Shandong Province/ ; ZR2018MC002//the Natural Science Foundation of Shandong Province/ ; UNPYSCT-2018139//Innovative Talent Project of Ministry of Education, Heilongjiang Province/ ; YJSCX2018-484HSD//Innovative Research Project of Graduate Students at Harbin university of commerce/ ; },
abstract = {In this study, the actual anti-biofouling (AF) efficacy of three protective coatings, including a chlorinated rubber-based coating (C₀) and two polydimethylsiloxane (PDMS)-based coatings (P₀ and PF), were estimated via the static field exposure assays. The surface properties of these protective coatings, including surface wettability and morphology features, were characterized using the static water contact angle (WCA) and scanning electron microscope (SEM). The colonization and succession dynamics of the early-adherent biofilm-forming eukaryotic microbial communities occupied on these protective coatings were explored using the Single-stranded Conformation Polymorphism (SSCP) technique. The field data clearly revealed that coating P₀ and PF performed better in the long-term static submergence, as compared with the C₀ surface, while coating PF showed excellent AF efficacy in the field. Fingerprinting analysis suggested that the diversity, abundance, the clustering patterns, and colonization dynamics of the early-colonized eukaryotic microbes were significantly perturbed by these protective coatings, particularly by the PF surfaces. These differential AF efficacy and perturbation effects would be largely ascribed to the differences in the wettability and surface nanostructures between the C₀, P₀ and PF surfaces, as evidenced by WCA and SEM analysis.},
}
@article {pmid30959988,
year = {2018},
author = {Othman, M and Rashid, H and Jamal, NA and Shaharuddin, SIS and Sulaiman, S and Hairil, HS and Khalid, K and Zakaria, MN},
title = {Effect of Cinnamon Extraction Oil (CEO) for Algae Biofilm Shelf-Life Prolongation.},
journal = {Polymers},
volume = {11},
number = {1},
pages = {},
doi = {10.3390/polym11010004},
pmid = {30959988},
issn = {2073-4360},
abstract = {This study was conducted to improve the life-span of the biofilm produced from algae by evaluating the decomposition rate with the effect of cinnamon extraction oil (CEO). The biofilm was fabricated using the solution casting technique. The soil burying analysis demonstrated low moisture absorption of the biofilm, thus decelerating the degradation due to low swelling rate and micro-organism activity, prolonging the shelf-life of the biofilm. Hence, the addition of CEO also affects the strength properties of the biofilm. The maximum tensile strength was achieved with the addition of 5% CEO, which indicated a good intermolecular interaction between the biopolymer (algae) and cinnamon molecules. The tensile strength, which was measured at 4.80 MPa, correlated with the morphological structure. The latter was performed using SEM, where the surface showed the absence of a separating phase between the biofilm and cinnamon blend. This was evidenced by FTIR analysis, which confirmed the occurrence of no chemical reaction between the biofilm and CEO during processing. The prolongation shelf-life rate of biofilm with good tensile properties are achievable with the addition of 5% of CEO.},
}
@article {pmid30959097,
year = {2019},
author = {Hnamte, S and Parasuraman, P and Ranganathan, S and Ampasala, DR and Reddy, D and Kumavath, RN and Suchiang, K and Mohanty, SK and Busi, S},
title = {Mosloflavone attenuates the quorum sensing controlled virulence phenotypes and biofilm formation in Pseudomonas aeruginosa PAO1: In vitro, in vivo and in silico approach.},
journal = {Microbial pathogenesis},
volume = {131},
number = {},
pages = {128-134},
doi = {10.1016/j.micpath.2019.04.005},
pmid = {30959097},
issn = {1096-1208},
abstract = {Quorum sensing (QS) is the cell density dependent communication network which coordinates the production of pathogenic determinants in majority of pathogenic bacteria. Pseudomonas aeruginosa causes hospital-acquired infections by virtue of its well-defined QS network. As the QS regulatory network in P. aeruginosa regulates the virulence determinants and antibiotic resistance, attenuating the QS system seems to be influential in developing next-generation anti-infective agents. In the current study, the QS attenuation potential of a flavonoid, mosloflavone was investigated against P. aeruginosa virulence and biofilm formation. Mosloflavone inhibited the pyocyanin production, LasB elastase and chitinase by 59.52 ± 2.74, 35.90 ± 4.34 and 61.18 ± 5.52% respectively. The QS regulated biofilm formation and development was also reduced when supplemented with sub-MIC of mosloflavone. The gene expression studies of mosloflavone using RT-PCR depicted its ability to down-regulate the expression levels of QS regulated virulence genes such as lasI (60.64%), lasR (91.70%), rhlI (57.30%), chiC (90.20%), rhlA (47.87%), rhlR (21.55%), lasB (37.80%), phzM (42.40%), toxA (61.00%), aprA (58.4%), exoS (78.01%), algD (46.60%) and pelA (50.45%). The down-regulation of QS virulence phenotypes by mosloflavone could be attributed to its binding affinity with the QS regulatory proteins, LasR and RhlR by competitively inhibiting the binding of natural autoinducers as evidenced from simulation studies. Mosloflavone also exhibited promising potential in controlling bacterial infection in Caenorhabditis elegans model system, in vivo. The anti-biofilm and anti-QS potential of mosloflavone in the current study illustrated the candidature of mosloflavone as a promising biocide.},
}
@article {pmid30958690,
year = {2019},
author = {Yin, L and Li, Q and Xue, M and Wang, Z and Tu, J and Song, X and Shao, Y and Han, X and Xue, T and Liu, H and Qi, K},
title = {The Role of the phoP Transcriptional Regulator on Biofilm Formation of Avian Pathogenic Escherichia Coli.},
journal = {Avian pathology : journal of the W.V.P.A},
volume = {},
number = {},
pages = {1-23},
doi = {10.1080/03079457.2019.1605147},
pmid = {30958690},
issn = {1465-3338},
abstract = {PhoP plays an important role as a transcriptional regulator in the two-component phoP/phoQ regulatory system, which is widely present in Gram-negative bacteria. In this study, we used DNA microarray-based technology to evaluate the role of phoP in biofilm formation in Avian Pathogenic Escherichia coli (APEC). Differences in gene transcription between APEC wild-type and phoP mutant strains were determined. Mutation of the phoP transcriptional regulator affects the expression profile of genes involved in processes such as flagellar assembly, ABC transporters, quorum sensing, and bacterial chemotaxis. Deletion of phoP in APEC reduced biofilm formation, as indicated by crystal violet staining and scanning electron microscopy (SEM). In addition, the phoP gene was found to be associated with changes in bacterial drug resistance and cell-membrane-related properties. This study shows that phoP plays an important regulatory role in APEC biofilm formation, and provides new insights into strategies for preventing and controlling APEC infection.},
}
@article {pmid30956871,
year = {2019},
author = {Kim, H and Moon, MJ and Kim, CY and Ryu, K},
title = {Efficacy of chemical sanitizers against Bacillus cereus on food contact surfaces with scratch and biofilm.},
journal = {Food science and biotechnology},
volume = {28},
number = {2},
pages = {581-590},
doi = {10.1007/s10068-018-0482-2},
pmid = {30956871},
issn = {2092-6456},
abstract = {This study was performed to investigate the efficacy of chemical sanitizers (viz., chlorine, chlorine dioxide, alcohol, and quaternary ammonium compound) against Bacillus cereus on five food contact materials under different conditions (smooth vs. scratched and with vs. without biofilms). After incubating materials in B. cereus suspension, cell adhesion on a smooth surface (10 cm2) was in the following ascending order: stainless steel (7.36 ± 0.08 log CFU), glass (7.51 ± 0.26 log CFU), polyethylene (7.66 ± 0.30 log CFU), polypropylene (7.76 ± 0.30 log CFU), and wood (8.02 ± 0.33 log CFU). The efficacy of sanitizers was dramatically reduced in the presence of a biofilm on all materials. Among four different chemical sanitizers, chlorine showed the best bactericidal activity against B. cereus on the surface with scratch and biofilm. Selection of adequate materials, maintenance of a smooth surface, and inhibition of biofilm formation are good practices for food safety.},
}
@article {pmid30956641,
year = {2019},
author = {Awan, AB and Schiebel, J and Böhm, A and Nitschke, J and Sarwar, Y and Schierack, P and Ali, A},
title = {Association of biofilm formation and cytotoxic potential with multidrug resistance in clinical isolates of Pseudomonas aeruginosa.},
journal = {EXCLI journal},
volume = {18},
number = {},
pages = {79-90},
pmid = {30956641},
issn = {1611-2156},
abstract = {Multidrug resistant (MDR) Pseudomonas aeruginosa having strong biofilm potential and virulence factors are a serious threat for hospitalized patients having compromised immunity. In this study, 34 P. aeruginosa isolates of human origin (17 MDR and 17 non-MDR clinical isolates) were checked for biofilm formation potential in enriched and minimal media. The biofilms were detected using crystal violet method and a modified software package of the automated VideoScan screening method. Cytotoxic potential of the isolates was also investigated on HepG2, LoVo and T24 cell lines using automated VideoScan technology. Pulse field gel electrophoresis revealed 10 PFGE types in MDR and 8 in non-MDR isolates. Although all isolates showed biofilm formation potential, strong biofilm formation was found more in enriched media than in minimal media. Eight MDR isolates showed strong biofilm potential in both enriched and minimal media by both detection methods. Strong direct correlation between crystal violet and VideoScan methods was observed in identifying strong biofilm forming isolates. High cytotoxic effect was observed by 4 isolates in all cell lines used while 6 other isolates showed high cytotoxic effect on T24 cell line only. Strong association of multidrug resistance was found with biofilm formation as strong biofilms were observed significantly higher in MDR isolates (p-value < 0.05) than non-MDR isolates. No significant association of cytotoxic potential with multidrug resistance or biofilm formation was found (p-value > 0.05). The MDR isolates showing significant cytotoxic effects and strong biofilm formation impose a serious threat for hospitalized patients with weak immune system.},
}
@article {pmid30955967,
year = {2019},
author = {Qu, Y and McGiffin, D and Kure, C and Ozcelik, B and Fraser, J and Thissen, H and Peleg, AY},
title = {Biofilm formation and migration on ventricular assist device drivelines.},
journal = {The Journal of thoracic and cardiovascular surgery},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jtcvs.2019.02.088},
pmid = {30955967},
issn = {1097-685X},
abstract = {OBJECTIVES: Driveline infections remain an important complication of ventricular assist device therapy, with biofilm formation being a major contributor. This study aimed to elucidate factors that govern biofilm formation and migration on clinically relevant ventricular assist device drivelines.<br><br>METHODS: Experimental analyses were performed on HeartWare HVAD (HeartWare International Inc, Framingham, Mass) drivelines to assess surface chemistry and biofilm formation. To mimic the driveline exit site, a drip-flow biofilm reactor assay was used. To mimic a subcutaneous tissue environment, a tunnel-based interstitial biofilm assay was developed. Clinical HVAD drivelines explanted at the time of cardiac transplantation were also examined by scanning electron microscopy.<br><br>RESULTS: Common causative pathogens of driveline infections were able to adhere to the smooth and velour sections of the HVAD driveline and formed robust biofilms in the drip-flow biofilm reactor; however, Pseudomonas aeruginosa and Candida albicans had greater biomass. Biofilm migration within the interstitial driveline tunnel was evident for Staphylococcus epidermidis, Staphylococcus aureus, and C albicans, but not P aeruginosa. Biofilm formation by staphylococci was 500 to 10,000 times higher in the tunnel-based model compared with our exit site model. The 3-dimensional structure of the driveline velour and the use of silicone adhesive in driveline manufacturing were found to promote biofilm growth, and explanted patient drivelines demonstrated inadequate tissue in-growth along the entire velour with micro-gaps between velour fibers.<br><br>CONCLUSIONS: This work highlights the predilection of pathogens to different parts of the driveline, the importance of the subcutaneous tunnel to biofilm formation and migration, and the presence of micro-gaps in clinical drivelines that could facilitate invasive driveline infections.},
}
@article {pmid30954574,
year = {2019},
author = {Le, KY and Villaruz, AE and Zheng, Y and He, L and Fisher, EL and Nguyen, TH and Ho, TV and Yeh, AJ and Joo, HS and Cheung, GYC and Otto, M},
title = {Role of Phenol-Soluble Modulins in Staphylococcus epidermidis Biofilm Formation and Infection of Indwelling Medical Devices.},
journal = {Journal of molecular biology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jmb.2019.03.030},
pmid = {30954574},
issn = {1089-8638},
abstract = {Phenol-soluble modulins (PSMs) are amphipathic, alpha-helical peptides that are secreted by staphylococci in high amounts in a quorum-sensing-controlled fashion. Studies performed predominantly in Staphylococcus aureus showed that PSMs structure biofilms, which results in reduced biofilm mass, while it has also been reported that S. aureus PSMs stabilize biofilms due to amyloid formation. We here analyzed the roles of PSMs in in vitro and in vivo biofilms of Staphylococcus epidermidis, the leading cause of indwelling device-associated biofilm infection. We produced isogenic deletion mutants for every S. epidermidis psm locus and a sequential deletion mutant in which production of all PSMs was abolished. In vitro analysis substantiated the role of all PSMs in biofilm structuring. PSM-dependent biofilm expansion was not observed, in accordance with our finding that no S. epidermidis PSM produced amyloids. In a mouse model of indwelling device-associated infection, the total psm deletion mutant had a significant defect in dissemination. Notably, the total psm mutant produced a significantly more substantial biofilm on the implanted catheter than the wild-type strain. Our study, which for the first time directly quantified the impact of PSMs on biofilm expansion on an implanted device, shows that the in vivo biofilm infection phenotype in S. epidermidis is in accordance with the PSM biofilm structuring and detachment model, which has important implications for the potential therapeutic application of quorum-sensing blockers.},
}
@article {pmid30953857,
year = {2019},
author = {Zan, F and Liang, Z and Jiang, F and Dai, J and Chen, G},
title = {Effects of food waste addition on biofilm formation and sulfide production in a gravity sewer.},
journal = {Water research},
volume = {157},
number = {},
pages = {74-82},
doi = {10.1016/j.watres.2019.03.061},
pmid = {30953857},
issn = {1879-2448},
abstract = {The conversion of food waste (FW) into the sewage system is regarded as a promising method of relieving the burden of solid waste management. However, knowledge about its effects on sewer processes is limited, particularly in terms of biofilm formation and sulfide production. In this study, a gravity sewer system was set up to investigate the effects of the addition of FW on biofilm formation, the sulfate-reducing bacteria (SRB) population, and the sulfide production potential. The sewer biofilm characteristics changed with long-term FW addition, and a greater thickness (by 32%), an increased dry density (by 13%), and more extracellular polymeric substance (by 141%) were observed. The thicker and denser biofilm limited oxygen diffusion, enlarged the anaerobic area in the sewer biofilm, promoted an increase in the SRB population, and enhanced the sulfide production potential in the gravity sewer. Substantial differences in the H2S profiles in the biofilm samples with and without the addition of FW were observed via microelectrode analysis. A model-based investigation of sewer biofilm formation with and without the addition of FW was conducted with a dynamic sewer biofilm model to gain further insights into sewer biofilm processes. The results suggest that the addition of FW can promote sulfide production and SRB growth in a sewer biofilm, which can be significantly affected by the ratio of FW to sewage. It is worth further investigations of the impacts of FW addition on the potential sulfide production in pressure sewers.},
}
@article {pmid30953693,
year = {2019},
author = {Kim, HR and Rhee, KJ and Eom, YB},
title = {Anti-biofilm and antimicrobial effects of zerumbone against Bacteroides fragilis.},
journal = {Anaerobe},
volume = {57},
number = {},
pages = {99-106},
doi = {10.1016/j.anaerobe.2019.04.001},
pmid = {30953693},
issn = {1095-8274},
abstract = {Enterotoxigenic Bacteroides fragilis (ETBF) can form biofilms in the colon mucosal membrane and may promote chronic infection and tumor formation. The objective of this study was to determine the effect of zerumbone extracted from Zingiber zerumbet (L.) Smith, on B. fragilis biofilm formation. Inhibitory effects of zerumbone on planktonic cell growth and biofilm formation were examined by crystal-violet biofilm assays and XTT metabolic assays. Results showed that zerumbone significantly inhibited biofilm formation and eradicated established biofilms. Furthermore, B. fragilis biofilms inhibited by zerumbone were observed by confocal laser scanning microscopy. qRT-PCR was used to support the phenotypic results and to investigate the expression levels of an efflux pump-related gene (bmeB). Specifically, among the efflux pump-related genes, zerumbone significantly suppressed the expression level of bmeB12. These results indicate that zerumbone might be a promising candidate as an anti-biofilm and antimicrobial agent to treat and prevent biofilm-related infections caused by B. fragilis.},
}
@article {pmid30953691,
year = {2019},
author = {Di Somma, A and Caterino, M and Soni, V and Agarwal, M and di Pasquale, P and Zanetti, S and Molicotti, P and Cannas, S and Nandicoori, VK and Duilio, A},
title = {The bifunctional protein GlmU is a key factor in biofilm formation induced by alkylating stress in Mycobacterium smegmatis.},
journal = {Research in microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.resmic.2019.03.002},
pmid = {30953691},
issn = {1769-7123},
abstract = {Living organisms have developed specific defence mechanisms to counteract hostile environmental conditions. Alkylation stress response mechanisms also occur in Mycobacterium tuberculosis (MTB) the pathogen responsible for tuberculosis. The effect of alkylating agents on the cellular growth of MTB was investigated using methyl methanesulfonate (MMS) as methyl donor demonstrating that limited doses of alkylating agents might affect MTB cell viability. A global investigation of Mycobacterium smegmatis response to alkylating stress was then pursued by differential proteomics to identify the most affected cellular pathways. Quantitative analysis of proteomic profiles demonstrated that most of the proteins upregulated in the presence of alkylating agents are involved in biofilm formation and/or cell wall biosynthesis. Tailored experiments confirmed that under stress conditions M. smegmatis elicits physical defence mechanisms by increasing biofilm formation. Among the upregulated proteins, we identified the GlmU bifunctional enzyme as a possible factor involved in biofilm production. Experiments with both conditional deletion and overexpressing glmU mutants demonstrated that down regulation of GlmU decreased M. smegmatis capabilities to produce biofilm whereas overexpression of the enzyme increased biofilm formation. These results were supported by inhibition of GlmU acetyltransferase activity with two different inhibitors, suggesting the involvement of this enzyme in the M. smegmatis defence mechanisms.},
}
@article {pmid30953053,
year = {2019},
author = {Walker, JN and Pinkner, CL and Lynch, AJL and Ortbal, S and Pinkner, JS and Hultgren, SJ and Myckatyn, TM},
title = {Deposition of Host Matrix Proteins on Breast Implant Surfaces Facilitates Staphylococcus Epidermidis Biofilm Formation: In Vitro Analysis.},
journal = {Aesthetic surgery journal},
volume = {},
number = {},
pages = {},
doi = {10.1093/asj/sjz099},
pmid = {30953053},
issn = {1527-330X},
abstract = {BACKGROUND: Staphylococcus epidermidis is a primary cause of breast implant-associated infection. S. epidermidis possesses several virulence factors that enable it to bind both abiotic surfaces and host factors to form a biofilm. S. epidermidis also colocalizes with matrix proteins coating explanted human breast implants.<br><br>OBJECTIVES: To identify matrix proteins that S. epidermidis may exploit to infect various breast implant surfaces in vitro.<br><br>METHODS: A combination of in vitro assays was used to characterize S. epidermidis strains isolated from human breast implants to gain a better understanding of how these bacteria colonize breast implant surfaces. These included determining the: (1) minimum inhibitory and bactericidal concentrations for irrigation solutions commonly used to prevent breast implant contamination; (2) expression and carriage of polysaccharide intercellular adhesin and serine-aspartate repeat proteins, which bind fibrinogen (SdrG) and collagen (SdrF), respectively; and (3) biofilm formation on varying implant surface characteristics, in different growth media, and supplemented with fibrinogen and Types I and III collagen. Scanning electron microscopy and immunofluorescence staining analyses were performed to corroborate findings from these assays.<br><br>RESULTS: Textured breast implant surfaces support greater bacterial biofilm formation at baseline, while the addition of collagen significantly increases biomass on all surfaces tested. We found that S. epidermidis isolated from breast implants all encoded SdrF. Consistent with this finding, these strains had a clear affinity for Type I collagen, forming dense, highly structured biofilms in its presence.<br><br>CONCLUSIONS: S . epidermidis may utilize SdrF to interact with Type I collagen to form biofilm on breast implant surfaces.},
}
@article {pmid30951891,
year = {2019},
author = {Philip, N and Bandara, HMHN and Leishman, SJ and Walsh, LJ},
title = {Effect of polyphenol-rich cranberry extracts on cariogenic biofilm properties and microbial composition of polymicrobial biofilms.},
journal = {Archives of oral biology},
volume = {102},
number = {},
pages = {1-6},
doi = {10.1016/j.archoralbio.2019.03.026},
pmid = {30951891},
issn = {1879-1506},
abstract = {OBJECTIVE: To investigate the effect of cranberry extracts on saliva-derived polymicrobial biofilms with regards to biofilm biomass, acidogenicity, exopolysaccharide (EPS)/microbial biovolumes, colony forming unit (CFU) counts, and the relative abundance of specific caries- and health-associated bacteria.<br><br>METHODS: Saliva-derived polymicrobial biofilms were grown for 96 h in a cariogenic environment and treated for 2 min every 12 h over the entire biofilm growth period with 500 μg/mL cranberry extract or vehicle control. The effect of the cranberry extract on biofilm behaviour was evaluated using different assays and its influence on key cariogenic and health-associated bacterial populations was assessed with a microarray real-time quantitative PCR method.<br><br>RESULTS: Cranberry-treated biofilms showed significant drops in biomass (38% reduction, P < 0.001), acidogenicity (44% reduction, P < 0.001), EPS/microbial biovolume ratios (P = 0.033), and CFU counts (51% reduction, P = 0.001). Furthermore, the cranberry extracts effected a significantly lower relative abundance of caries-associated Streptococcus sobrinus (fold change 0.004, P = 0.002) and Provotella denticola (0.002, P < 0.001), and a significantly higher relative abundance of the health-associated Streptococcus sanguinis (fold change 90.715, P = 0.001).<br><br>CONCLUSIONS: The cranberry extract lowered biofilm biomass, acidogenicity, EPS/microbial biovolumes, CFU counts, and modulated a beneficial microbial ecological change in saliva-derived polymicrobial biofilms.},
}
@article {pmid30951818,
year = {2019},
author = {Chen, X and Li, P and Shen, Y and Zou, Y and Yuan, G and Hu, H},
title = {Rhamnolipid-involved antibiotics combinations improve the eradication of Helicobacter pylori biofilm in vitro: A comparison with conventional triple therapy.},
journal = {Microbial pathogenesis},
volume = {131},
number = {},
pages = {112-119},
doi = {10.1016/j.micpath.2019.04.001},
pmid = {30951818},
issn = {1096-1208},
abstract = {Antibiotics resistance of H. pylori has been increasing constantly accompanied with decreasing clearance rate clinically, which is demonstrated to be closely related to biofilms with higher resistance than planktonic bacteria for the dense extracellular polymeric substances. Rhamnolipid (RHL) is proved to not only damage the structure of biofilm, but also potentially inhibit bacterial adhesion. To investigate if RHL could promote eradicating rate of the conventional triple therapy to H. pylori biofilm and hence attenuate the resistance and relapse of H. pylori, first-line antibiotics clarithromycin (CLR), amoxicillin (AMX) or/and proton pump inhibitor (PPI) involved single, dual or triple therapies were compared with RHL-containing drug combinations on eradicating H. pylori biofilm. The residual biofilm biomass, the survival of bacteria inside the remaining biofilm and the planktonic bacteria dispersed from the biofilm after treatment were tested. Combination with RHL significantly improved the ability of antibiotics to eradicate H. pylori biofilm, especially RHL combined with AMX and PPI could eradicate more than 95% of biofilm showing much more effective ability than the conventional triple therapy CLR + AMX + PPI. Additionally, the combination of RHL and antibiotics could effectively inhibit the biofilm formation at lower concentration. Thus, RHL might be used as a potential antibiotic adjuvant on anti-H. pylori therapy to enhance eradicating ability of antibiotics to biofilms.},
}
@article {pmid30951240,
year = {2019},
author = {Jayaraman, N and Mahapa, A and Samanta, GC and Maiti, K and Chatterji, D},
title = {Mannopyranoside Glycolipids Inhibit Mycobacterial Growth, Biofilm and Potentiate Isoniazid Inhibition Activities in M. smegmatis.},
journal = {Chembiochem : a European journal of chemical biology},
volume = {},
number = {},
pages = {},
doi = {10.1002/cbic.201900040},
pmid = {30951240},
issn = {1439-7633},
abstract = {Lipomannan and lipoarabinomannan are integral components of mycobacterial cell wall. Our earlier studies demonstrated that synthetic arabinan and arabinomannan glycolipids act as inhibitors of mycobacterial growth, in addition to exhibiting inhibitory activities of mycobacterial biofilm. In the present study, we demonstrate that synthetic mannan glycolipids are better inhibitors of the mycobacterial growth, whereas, lipoarabinomannan has higher inhibition efficiencies to biofilm. Syntheses of mannan glycolipids with graded number of mannan moieties and an arabinomannan glycolipid are conducted by chemical methods and subsequent mycobacterial growth and biofilm inhibition studies are conducted on M. smegmatis. Growth inhibition of 73 ± 3% is observed with a mannose trisaccharide containing glycolipid, whereas this glycolipid did not promote biofilm inhibition activity better than arabinomannan glycolipid. The antibiotic supplementation activities of glycolipids on growth and biofilm inhibitions are evaluated. Fold increases in the growth and biofilm inhibitions are observed when the antibiotic is supplemented with glycolipids, leading to a significant reduction of inhibition concentrations of the antibiotic.},
}
@article {pmid30950296,
year = {2019},
author = {Emeri, FTAS and Rosalen, PL and Paganini, ÉR and Garcia, MAR and Nazaré, AC and Lazarini, JG and Alencar, SM and Regasini, LO and Sardi, JCO},
title = {Antimicrobial activity of nitrochalcone and pentyl caffeate against hospital pathogens results in decreased microbial adhesion and biofilm formation.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-14},
doi = {10.1080/08927014.2019.1574763},
pmid = {30950296},
issn = {1029-2454},
abstract = {The present study investigated the antimicrobial, anti-adhesion and anti-biofilm activity of the modified synthetic molecules nitrochalcone (NC-E05) and pentyl caffeate (C5) against microorganisms which have a high incidence in hospital-acquired infections. The compounds were further tested for their preliminary systemic toxicity in vivo. NC-E05 and C5 showed antimicrobial activity, with minimum inhibitory concentrations (MICs) ranging between 15.62 and 31.25 μg ml-1. Treatment with NC-E05 and C5 at 1 × MIC and/or 10 × MIC significantly reduced mono or mixed-species biofilm formation and viability. At MIC/2, the compounds decreased microbial adhesion to HaCaT keratinocytes from 1 to 3 h (p < 0.0001). In addition, NC-E05 and C5 demonstrated low toxicity in vivo in the Galleria mellonella model at anti-biofilm concentrations. Thus, the chemical modification of these molecules proved to be effective in the proposed anti-biofilm activity, opening opportunities for the development of new antimicrobials.},
}
@article {pmid30950292,
year = {2019},
author = {Ikram, S and Heikal, A and Finke, S and Hofgaard, A and Rehman, Y and Sabri, AN and Økstad, OA},
title = {Bacillus cereus biofilm formation on central venous catheters of hospitalised cardiac patients.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-13},
doi = {10.1080/08927014.2019.1586889},
pmid = {30950292},
issn = {1029-2454},
abstract = {Formation of bacterial biofilms is a risk with many in situ medical devices. Biofilm-forming Bacillus species are associated with potentially life-threatening catheter-related blood stream infections in immunocompromised patients. Here, bacteria were isolated from biofilm-like structures within the lumen of central venous catheters (CVCs) from two patients admitted to cardiac hospital wards. Isolates belonged to the Bacillus cereus group, exhibited strong biofilm formation propensity, and mapped phylogenetically close to the B. cereus emetic cluster. Together, whole genome sequencing and quantitative PCR confirmed that the isolates constituted the same strain and possessed a range of genes important for and up-regulated during biofilm formation. Antimicrobial susceptibility testing demonstrated resistance to trimethoprim-sulphamethoxazole, clindamycin, penicillin and ampicillin. Inspection of the genome revealed several chromosomal β-lactamase genes and a sulphonamide resistant variant of folP. This study clearly shows that B. cereus persisting in hospital ward environments may constitute a risk factor from repeated contamination of CVCs.},
}
@article {pmid30949776,
year = {2019},
author = {Chang, RYK and Das, T and Manos, J and Kutter, E and Morales, S and Chan, HK},
title = {Bacteriophage PEV20 and Ciprofloxacin Combination Treatment Enhances Removal of Pseudomonas aeruginosa Biofilm Isolated from Cystic Fibrosis and Wound Patients.},
journal = {The AAPS journal},
volume = {21},
number = {3},
pages = {49},
doi = {10.1208/s12248-019-0315-0},
pmid = {30949776},
issn = {1550-7416},
abstract = {Antibiotic resistance in Pseudomonas aeruginosa biofilms necessitates the need for novel antimicrobial therapy with anti-biofilm properties. Bacteriophages (phages) are recognized as an ideal biopharmaceutical for combating antibiotic-resistant bacteria especially when used in combination with antibiotics. However, previous studies primarily focused on using phages against of P. aeruginosa biofilms of laboratory strains. In the present study, biofilms of six P. aeruginosa isolated from cystic fibrosis and wound patients, and one laboratory strain was treated singly and with combinations of anti-Pseudomonas phage PEV20 and ciprofloxacin. Of these strains, three were highly susceptible to the phage, while one was partially resistant and one was completely resistant. Combination treatment with PEV20 and ciprofloxacin enhanced biofilm eradication compared with single treatment. Phage and ciprofloxacin synergy was found to depend on phage-resistance profile of the target bacteria. Furthermore, phage and ciprofloxacin combination formulation protected the lung epithelial and fibroblast cells from P. aeruginosa and promoted cell growth. The results demonstrated that thorough screening of phage-resistance is crucial for designing phage-antibiotic formulation. The addition of highly effective phage could reduce the ciprofloxacin concentration required to combat P. aeruginosa infections associated with biofilm in cystic fibrosis and wound patients.},
}
@article {pmid30949441,
year = {2019},
author = {Buetti-Dinh, A and Galli, V and Bellenberg, S and Ilie, O and Herold, M and Christel, S and Boretska, M and Pivkin, IV and Wilmes, P and Sand, W and Vera, M and Dopson, M},
title = {Deep neural networks outperform human expert's capacity in characterizing bioleaching bacterial biofilm composition.},
journal = {Biotechnology reports (Amsterdam, Netherlands)},
volume = {22},
number = {},
pages = {e00321},
doi = {10.1016/j.btre.2019.e00321},
pmid = {30949441},
issn = {2215-017X},
abstract = {Background: Deep neural networks have been successfully applied to diverse fields of computer vision. However, they only outperform human capacities in a few cases.<br><br>Methods: The ability of deep neural networks versus human experts to classify microscopy images was tested on biofilm colonization patterns formed on sulfide minerals composed of up to three different bioleaching bacterial species attached to chalcopyrite sample particles.<br><br>Results: A low number of microscopy images per category (<600) was sufficient for highly efficient computational analysis of the biofilm's bacterial composition. The use of deep neural networks reached an accuracy of classification of ∼90% compared to ∼50% for human experts.<br><br>Conclusions: Deep neural networks outperform human experts' capacity in characterizing bacterial biofilm composition involved in the degradation of chalcopyrite. This approach provides an alternative to standard, time-consuming biochemical methods.},
}
@article {pmid30949156,
year = {2019},
author = {He, X and Li, S and Yin, Y and Xu, J and Gong, W and Li, G and Qian, L and Yin, Y and He, X and Guo, T and Huang, Y and Lu, F and Cao, J},
title = {Membrane Vesicles Are the Dominant Structural Components of Ceftazidime-Induced Biofilm Formation in an Oxacillin-Sensitive MRSA.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {571},
doi = {10.3389/fmicb.2019.00571},
pmid = {30949156},
issn = {1664-302X},
abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) has received increasing attention in recent years. However, the characteristics and relevant mechanisms of biofilm formation in oxacillin-sensitive MRSA (OS-MRSA) are poorly understood. This study was designed to characterize biofilm formation in OS-MRSA BWSA15 in response to ceftazidime (TZ) by comparing the methicillin-sensitive S. aureus (MSSA) strain BWSA23 and the oxacillin-resistant MRSA (OR-MRSA) strain BWSA11. The biofilms and biofilm-forming cells were observed by electron microscopy. Biofilms grown on microtiter plates were chemically decomposed and analyzed by Fourier transform infrared spectroscopy. The transcriptional regulation of genes associated with methicillin resistance, surface adhesion, fatty acid biosynthesis, and global regulation (sigma B) was investigated. A significant increase in biofilm formation ability (10.21-fold) and aggregation ability (2.56-fold) was observed in BWSA15 upon the treatment with TZ (16 μg/ml). The TZ-induced biofilm formation in BWSA15 was characterized by a disappearance of polysaccharide-like extracellular substances and an appearance of a large number of intercellular MVs from extracellular matrix. Few MVs were identified in the biofilms formed by BWSA11 and BWSA23. There was a significant upregulation of mecA, sigB, and fatty acid biosynthesis-associated genes and downregulation of icaA, icaD, clfA, clfB, and fnaA in BWSA15 upon the treatment with TZ. The formation of intracellular junctions of MVs in the biofilms of BWSA15 was mediated by a significant increase in the proportion of proteins as well as by an increase in the proportion of non-ionized carboxyl groups in fatty acids. This study demonstrated that beta-lactam antibiotics can induce biofilm formation in OS-MRSA, and the biofilm induction in OS-MRSA can mainly be attributed to exposed MVs with increased hydrophobicity rather than polysaccharide intercellular adhesins, cell wall-anchored surface proteins, and extracellular DNA.},
}
@article {pmid30949142,
year = {2019},
author = {Ashrafudoulla, M and Mizan, MFR and Park, H and Byun, KH and Lee, N and Park, SH and Ha, SD},
title = {Genetic Relationship, Virulence Factors, Drug Resistance Profile and Biofilm Formation Ability of Vibrio parahaemolyticus Isolated From Mussel.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {513},
doi = {10.3389/fmicb.2019.00513},
pmid = {30949142},
issn = {1664-302X},
abstract = {The objective of this study was to investigate the virulence factors, genetic relationship, antibiotic resistance profile and the biofilm formation ability of Vibrio parahaemolyticus isolates on shrimp and mussel surfaces at 30°C. In this study, eight (n = 8) V. parahaemolyticus isolated from mussel were examined. We used the polymerase chain reaction (PCR) to examine the distribution of different genes, and Repetitive Extragenic Palindromic-PCR (REP-PCR) to compare the genetic relationship. Disk diffusion technique was used to assess antibiotic and multiple-antibiotic resistance. The biofilm formation assay, and field emission scanning electron microscopy (FE-SEM) were used to evaluate biofilm formation ability. Transmission Electron Microscope (TEM) was used to observe the morphological structure of bacterial cell. Our results indicated that the biofilm-associated genes, 16S rRNA, toxR, and tdh, were present in all the tested V. parahaemolyticus isolates (n = 8). Approximately, 62.5% (5 isolates among 8 isolates) isolates showed strong multiple-antibiotic resistance index with an average value of 0.56. All isolates (n = 8) showed strong genetic relationship and significant biofilm formation ability on shrimp and mussel surfaces. This study demonstrated that the presence of virulence factors, high multiple antibiotic resistance index (MARI) values, and effective biofilm formation ability of V. parahaemolyticus isolates could be a great threat to human health and economic values in future. It was also suggested that a high resistance rate to antibiotic could be ineffective for treating V. parahaemolyticus infections. The continuous monitoring of V. parahaemolyticus antibiotic, molecular and biofilm characteristics is needed to increase seafood safety.},
}
@article {pmid30948051,
year = {2019},
author = {Sedki, M and Hassan, RYA and Andreescu, S and El-Sherbiny, IM},
title = {Online-monitoring of biofilm formation using nanostructured electrode surfaces.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {100},
number = {},
pages = {178-185},
doi = {10.1016/j.msec.2019.02.112},
pmid = {30948051},
issn = {1873-0191},
abstract = {The direct monitoring of biofilm formation enables valuable insights into the industrial processes, microbiology, and biomedical applications. Therefore, in the present study, nano-structured bioelectrochemical platforms were designed for sensing the formation of biofilm of P. aeruginosa along with monitoring its electrochemical/morphological changes under different stresses. Through the assay optimizations, the performances of different electrode modifiers such as reduced graphene oxide (rGO) nanosheets, hyperbranched chitosan nanoparticles (HBCs NPs), and rGO-HBCs nano-composite were tested to assess the influence of the electrode materials on biofilm progression. As a need for the anodic respiration, the bioelectrochemical responses of the adhered bacterial cells changed from a non-electrochemically active (planktonic state) to an electrochemically active (biofilm matrix) state. Our results demonstrated that electrode modifications with conductive nanostructured elements is highly sensitive and enable direct assay for the biofilm formation without any preachments. Consequently, the morphological changes in bacterial cell wall, upon switching from the planktonic state to the biofilm matrix were imaged using scanning electron microscopy (SEM), and the changes in cell wall chemical composition were monitored by the Energy Dispersive X-ray analysis (EDX). Thus, the designed microbial electrochemical system (MES) was successfully used to monitor changes in the biofilm matrix under different stresses through direct measurements of electron exchanges.},
}
@article {pmid30947504,
year = {2019},
author = {Paricio, L and Neufeld, B and Reynolds, M},
title = {Combined influence of nitric oxide and surface roughness in biofilm reduction across bacteria strains.},
journal = {Biointerphases},
volume = {14},
number = {2},
pages = {021004},
doi = {10.1116/1.5089246},
pmid = {30947504},
issn = {1559-4106},
abstract = {Effective use of medical device implants is often hindered by infection, which may cause the device to be rejected from the body and seriously endanger health. Such infections are often a result of biofilm formation or microbial colonies collecting on a surface. Therefore, a challenge in the medical field is to mitigate the impact of biofilm formation in order to save thousands of lives and millions of healthcare dollars annually. The proposed strategy is to target the attachment phase of the biofilm lifecycle to try to prevent the formation of antimicrobial resistant biofilms. Prevention of bacterial attachment may be induced through the introduction of nitric oxide (NO), a small biological signaling molecule known for its antibacterial properties. NO may be delivered via release from a donating molecule incorporated in the polymer composing the medical device. The NO donor S-nitrosoglutathione (GSNO) was utilized in this study because it is a relatively stable small molecule that naturally exists in the body, therefore negating possible adverse reactions when it is introduced to the body. Tygon®, a polymer commonly found in Food and Drug Administration approved medical devices such as catheters, was utilized as a platform for the inhibition of biofilms. To study the necessary amount of released NO needed to cause a reduction in attachment across varying strains, different concentrations of GSNO were applied. Two Gram-negative (Pseudomonas aeruginosa and Acinetobacter baumannii) and two Gram-positive species (Staphylococcus aureus and Methicillin Resistant Staphylococcus aureus), all strong biofilm formers listed as urgent threats by the Center for Disease Control, illustrated different responses to NO. Gram-positive species showed a decrease in viability over 80% with an average total NO release of 2.01 ± 2.11 × 10 - 4 μmols, while Gram-negative response was less, with viability decreasing to 38% (P. aeruginosa) and 71% (A. baumannii) with 1.25 ± 1.63 × 10-4 μmols NO. Further studies utilizing glutathione surface roughness controls highlight that increasing the surface roughness of the polymer platform produces no statistically significant difference in viability compared to the Tygon-only negative control in all strains except P. aeruginosa. Developing a quantitative understanding of how NO release and platform surface roughness impact biofilm attachment across Gram strains is key to reducing the incidence and impact of medical device associated infections.},
}
@article {pmid30946803,
year = {2019},
author = {Feng, J and Li, T and Yee, R and Yuan, Y and Bai, C and Cai, M and Shi, W and Embers, M and Brayton, C and Saeki, H and Gabrielson, K and Zhang, Y},
title = {Stationary phase persister/biofilm microcolony of Borrelia burgdorferi causes more severe disease in a mouse model of Lyme arthritis: implications for understanding persistence, Post-treatment Lyme Disease Syndrome (PTLDS), and treatment failure.},
journal = {Discovery medicine},
volume = {27},
number = {148},
pages = {125-138},
pmid = {30946803},
issn = {1944-7930},
abstract = {Although most patients with Lyme disease can be cured with a 2-4 week antibiotic therapy, about 10-20% of patients continue to suffer prolonged persistent symptoms, a condition called post-treatment Lyme disease syndrome (PTLDS). The cause for PTLDS is unclear and hotly debated. Borrelia burgdorferi develops morphological variants under stress conditions but their significance is not clear. Here we isolated the biofilm-like microcolony (MC) and planktonic (spirochetal form and round body) (SP) variant forms from the stationary phase culture of B. burgdorferi and showed that the MC and SP variant forms were not only more tolerant to the current Lyme antibiotics but also caused more severe arthritis in mice than the log phase spirochete form (LOG). We propose to divide the persistent Lyme disease into two categories: (1) early development of persistent disease from inoculation with persister/biofilm at the beginning of infection introduced by tick bites, or Type I persistent disease (i.e., PTLDS); and (2) late development of persistent disease due to initial infection not being diagnosed or treated in time such that the infection develops into late persistent disease, or Type II persistent disease. Importantly, we show that the murine infection caused by LOG could be eradicated by ceftriaxone whereas the persistent infection established with MC could not be eradicated by doxycycline (Doxy), ceftriaxone (CefT), or vancomycin (Van), or Doxy+CefT or Van+CefT, but could only be eradicated by the persister drug combination daptomycin+doxycycline+ceftriaxone. We conclude that varying levels of persistence and pathologies of Borrelia infection and the corresponding different treatment responses are mostly dictated by the heterogeneous B. burgdorferi variant forms inoculated at the time of tick bites. These findings may have broad implications for understanding pathogenesis and treatment of not only persistent Lyme disease but also other persistent infections in general and call for studies to evaluate if treatment of persistent infections with persister drug combination regimens is more effective than the current mostly single-antibiotic monotherapy.},
}
@article {pmid30941317,
year = {2019},
author = {Zhang, B and Ku, X and Zhang, X and Zhang, Y and Chen, G and Chen, F and Zeng, W and Li, J and Zhu, L and He, Q},
title = {The AI-2/luxS Quorum Sensing System Affects the Growth Characteristics, Biofilm Formation, and Virulence of Haemophilus parasuis.},
journal = {Frontiers in cellular and infection microbiology},
volume = {9},
number = {},
pages = {62},
doi = {10.3389/fcimb.2019.00062},
pmid = {30941317},
issn = {2235-2988},
abstract = {Haemophilus parasuis (H. parasuis) is a kind of opportunistic pathogen of the upper respiratory tract of piglets. Under certain circumstances, virulent strains can breach the mucosal barrier and enter the bloodstream, causing severe Glässer's disease. Many virulence factors are found to be related to the pathogenicity of H. parasuis strain, but the pathogenic mechanism remains unclear. LuxS/AI-2, as a kind of very important quorum sensing system, affects the growth characteristics, biofilm formation, antibiotic production, virulence, and metabolism of different strains. In order to investigate the effect of luxS/AI-2 quorum sensing system on the virulence of H. parasuis, a deletion mutant strain (ΔluxS) and complemented strain (C-luxS) were constructed and characterized. The results showed that the luxS gene participated in regulating and controlling stress resistance, biofilm formation and virulence. Compared with wild-type strain, ΔluxS strain decreased the production of AI-2 molecules and the tolerance toward oxidative stress and heat shock, and it reduced the abilities of autoagglutination, hemagglutination, and adherence, whereas it increased the abilities to form biofilm in vitro. In vivo experiments showed that ΔluxS strain attenuated its virulence about 10-folds and significantly decreased its tissue burden of bacteria in mice, compared with the wild-type strain. Taken together, the luxS/AI-2 quorum sensing system in H. parasuis not only plays an important role in growth and biofilm formation, but also affects the pathogenicity of H. parasuis.},
}
@article {pmid30941169,
year = {2019},
author = {Shridhar, S and Dhanashree, B},
title = {Antibiotic Susceptibility Pattern and Biofilm Formation in Clinical Isolates of Enterococcus spp.},
journal = {Interdisciplinary perspectives on infectious diseases},
volume = {2019},
number = {},
pages = {7854968},
doi = {10.1155/2019/7854968},
pmid = {30941169},
issn = {1687-708X},
abstract = {Enterococcus is a commensal in the intestine and is now emerging as a drug-resistant pathogen. It produces different virulence factors. Enterococcus surface protein (esp) is a virulence factor that helps in the adhesion, but its role in biofilm formation is still contradictory. Moreover, in many bacterial species, strong biofilm producer exhibits multidrug resistance. Hence, this study is done to know the antimicrobial susceptibility pattern of Enterococcus spp. and to correlate the drug resistance with biofilm production and esp gene. Enterococcal isolates were collected from various clinical specimens. Antibiotic susceptibility testing was done by disc diffusion, and biofilm production was performed by microtiter plate method. PCR was performed for detection of esp gene. Two E. faecium strains resistant to vancomycin and high-level aminoglycoside (HLAR) were non-biofilm-producers and did not harbor esp gene. However, other biofilm-producing E. faecium harbored esp gene, and this association was found to be statistically significant (p=0.024). It was observed that there was no significant association between biofilm formation and presence of esp gene in E. faecalis. Moreover, a significant correlation was not found between drug resistance and biofilm production in both Enterococcus species. Thus, biofilm formation is not always associated with the presence or absence of esp gene and or drug resistance in Enterococcus spp.},
}
@article {pmid30941112,
year = {2019},
author = {Sobisch, LY and Rogowski, KM and Fuchs, J and Schmieder, W and Vaishampayan, A and Oles, P and Novikova, N and Grohmann, E},
title = {Biofilm Forming Antibiotic Resistant Gram-Positive Pathogens Isolated From Surfaces on the International Space Station.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {543},
doi = {10.3389/fmicb.2019.00543},
pmid = {30941112},
issn = {1664-302X},
abstract = {The International Space Station (ISS) is a closed habitat in a uniquely extreme and hostile environment. Due to these special conditions, the human microflora can undergo unusual changes and may represent health risks for the crew. To address this problem, we investigated the antimicrobial activity of AGXX®, a novel surface coating consisting of micro-galvanic elements of silver and ruthenium along with examining the activity of a conventional silver coating. The antimicrobial materials were exposed on the ISS for 6, 12, and 19 months each at a place frequently visited by the crew. Bacteria that survived on the antimicrobial coatings [AGXX® and silver (Ag)] or the uncoated stainless steel carrier (V2A, control material) were recovered, phylogenetically affiliated and characterized in terms of antibiotic resistance (phenotype and genotype), plasmid content, biofilm formation capacity and antibiotic resistance transferability. On all three materials, surviving bacteria were dominated by Gram-positive bacteria and among those by Staphylococcus, Bacillus and Enterococcus spp. The novel antimicrobial surface coating proved to be highly effective. The conventional Ag coating showed only little antimicrobial activity. Microbial diversity increased with increasing exposure time on all three materials. The number of recovered bacteria decreased significantly from V2A to V2A-Ag to AGXX®. After 6 months exposure on the ISS no bacteria were recovered from AGXX®, after 12 months nine and after 19 months three isolates were obtained. Most Gram-positive pathogenic isolates were multidrug resistant (resistant to more than three antibiotics). Sulfamethoxazole, erythromycin and ampicillin resistance were most prevalent. An Enterococcus faecalis strain recovered from V2A steel after 12 months exposure exhibited the highest number of resistances (n = 9). The most prevalent resistance genes were ermC (erythromycin resistance) and tetK (tetracycline resistance). Average transfer frequency of erythromycin, tetracycline and gentamicin resistance from selected ISS isolates was 10-5 transconjugants/recipient. Most importantly, no serious human pathogens such as methicillin resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococci (VRE) were found on any surface. Thus, the infection risk for the crew is low, especially when antimicrobial surfaces such as AGXX® are applied to surfaces prone to microbial contamination.},
}
@article {pmid30940828,
year = {2019},
author = {Ghosh, R and Barman, S and Mandal, NC},
title = {Phosphate deficiency induced biofilm formation of Burkholderia on insoluble phosphate granules plays a pivotal role for maximum release of soluble phosphate.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {5477},
doi = {10.1038/s41598-019-41726-9},
pmid = {30940828},
issn = {2045-2322},
support = {DST/INSPIRE Fellowship/2011/ 170C//Department of Science and Technology, Ministry of Science and Technology (DST)/ ; DST/INSPIRE Fellowship/2011/ 170C//Department of Science and Technology, Ministry of Science and Technology (DST)/ ; DST/INSPIRE Fellowship/2011/ 170C//Department of Science and Technology, Ministry of Science and Technology (DST)/ ; },
abstract = {Involvement of biofilm formation process during phosphate (P) solubilization by rhizobacterial strains is not clearly understood. Scanning electron microscopic observations revealed prominent biofilm development on tricalcium phosphate as well as on four different rock phosphate granules by two P solubilizing rhizobacteria viz. Burkholderia tropica P4 and B. unamae P9. Variation in the biofilm developments were also observed depending on the total P content of insoluble P used. Biofilm quantification suggested a strong correlation between the amounts of available P and degrees of biofilm formation. Lower concentrations of soluble P directed both the organisms towards compact biofilm development with maximum substratum coverage. Variation in the production of extracellular polymeric substances (EPS) in the similar pattern also suggested its close relationship with biofilm formation by the isolates. Presence of BraI/R quorum sensing (QS) system in both the organisms were detected by PCR amplification and sequencing of two QS associated genes viz. braR and rsaL, which are probably responsible for biofilm formation during P solubilization process. Overall observations help to hypothesize for the first time that, biofilm on insoluble P granules creates a close environment for better functioning of organic acids secreted by Burkholderia strains for maximum P solubilization during P deficient conditions.},
}
@article {pmid30940709,
year = {2019},
author = {Beebout, CJ and Eberly, AR and Werby, SH and Reasoner, SA and Brannon, JR and De, S and Fitzgerald, MJ and Huggins, MM and Clayton, DB and Cegelski, L and Hadjifrangiskou, M},
title = {Respiratory Heterogeneity Shapes Biofilm Formation and Host Colonization in Uropathogenic Escherichia coli.},
journal = {mBio},
volume = {10},
number = {2},
pages = {},
doi = {10.1128/mBio.02400-18},
pmid = {30940709},
issn = {2150-7511},
support = {K08 DK106472/DK/NIDDK NIH HHS/United States ; R01 AI107052/AI/NIAID NIH HHS/United States ; T32 GM007347/GM/NIGMS NIH HHS/United States ; U24 DK076169/DK/NIDDK NIH HHS/United States ; },
abstract = {Biofilms are multicellular bacterial communities encased in a self-secreted extracellular matrix comprised of polysaccharides, proteinaceous fibers, and DNA. Organization of these components lends spatial organization to the biofilm community such that biofilm residents can benefit from the production of common goods while being protected from exogenous insults. Spatial organization is driven by the presence of chemical gradients, such as oxygen. Here we show that two quinol oxidases found in Escherichia coli and other bacteria organize along the biofilm oxygen gradient and that this spatially coordinated expression controls architectural integrity. Cytochrome bd, a high-affinity quinol oxidase required for aerobic respiration under hypoxic conditions, is the most abundantly expressed respiratory complex in the biofilm community. Depletion of the cytochrome bd-expressing subpopulation compromises biofilm complexity by reducing the abundance of secreted extracellular matrix as well as increasing cellular sensitivity to exogenous stresses. Interrogation of the distribution of quinol oxidases in the planktonic state revealed that ∼15% of the population expresses cytochrome bd at atmospheric oxygen concentration, and this population dominates during acute urinary tract infection. These data point toward a bet-hedging mechanism in which heterogeneous expression of respiratory complexes ensures respiratory plasticity of E. coli across diverse host niches.IMPORTANCE Biofilms are multicellular bacterial communities encased in a self-secreted extracellular matrix comprised of polysaccharides, proteinaceous fibers, and DNA. Organization of these components lends spatial organization in the biofilm community. Here we demonstrate that oxygen gradients in uropathogenic Escherichia coli (UPEC) biofilms lead to spatially distinct expression programs for quinol oxidases-components of the terminal electron transport chain. Our studies reveal that the cytochrome bd-expressing subpopulation is critical for biofilm development and matrix production. In addition, we show that quinol oxidases are heterogeneously expressed in planktonic populations and that this respiratory heterogeneity provides a fitness advantage during infection. These studies define the contributions of quinol oxidases to biofilm physiology and suggest the presence of respiratory bet-hedging behavior in UPEC.},
}
@article {pmid30939384,
year = {2019},
author = {Wu, ZY and Liu, Y and Wang, SY and Peng, P and Li, XY and Xu, J and Li, WH},
title = {A novel integrated system of three-dimensional electrochemical reactors (3DERs) and three-dimensional biofilm electrode reactors (3DBERs) for coking wastewater treatment.},
journal = {Bioresource technology},
volume = {284},
number = {},
pages = {222-230},
doi = {10.1016/j.biortech.2019.03.123},
pmid = {30939384},
issn = {1873-2976},
abstract = {Treatment of coking wastewater is a great challenge due to their instinct characteristics of high concentration, complex composition and biological toxicity. In this work, a novel integrated system comprising three-dimensional electrochemical reactors (3DERs) and three-dimensional biofilm electrode reactors (3DBERs) in series is developed for coking wastewater treatment. Results indicate that 79.63% of COD as well as 76.30% of total nitrogen could be removed at the low energy consumption of 15.6 kWh/m3. 3DERs mainly contribute to COD and nitrogen removal through electrochemical oxidation/reduction, while 3DBERs are responsible for nitrification process by enriched functional microbes. After treating by the integrated system, only long-chain alkanes are left in the wastewater and the toxicity of effluent is significantly reduced. This integrated 3DERs-3DBERs system exhibits capability of simultaneously eliminating carbonaceous and nitrogenous contaminants in coking wastewater, and greatly saves the energy with synergy of electricity and biofilm.},
}
@article {pmid30937747,
year = {2019},
author = {Li, J and Zhu, W and Dong, H and Yang, Z and Zhang, P and Qiang, Z},
title = {Impact of carrier on ammonia and organics removal from zero-discharge marine recirculating aquaculture system with sequencing batch biofilm reactor (SBBR).},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-019-04887-8},
pmid = {30937747},
issn = {1614-7499},
support = {51878362//National Natural Science Foundation of China/ ; 2017M610410//China Postdoctoral Science Foundation/ ; 2018T110665//China Postdoctoral Science Foundation/ ; 18K02ESPCR//State Key Joint Laboratory of Environment Simulation and Pollution Control/ ; },
abstract = {Marine recirculating aquaculture system (MRAS) is an effective technology that provides sustainable farming of food fish globally. However, dissolved organics material (chemical oxygen demand, COD) and especially ammonia are produced from uneaten feed and metabolic wastes of fish. To purify the MRAS water, this study adopted a sequencing biofilm batch reactor (SBBR) and comparatively investigated the performances of four different carriers on ammonia and COD removal. Results indicated that the NH4+-N removal rates were 0.045 ± 0.05, 0.065 ± 0.008, 0.089 ± 0.005, and 0.093 ± 0.003 kg/(m3·d), and the COD removal rates were 0.019 ± 0.010, 0.213 ± 0.010, 0.255 ± 0.015, and 0.322 ± 0.010 kg/(m3·d) in the SBBRs packed with porous plastic, bamboo ring, maifan stone, and ceramsite carriers, respectively. Among the four carriers, ceramsite exhibited the best performance for both NH4+-N (80%) and COD (33%) removal after the SBBR reached the steady-state operation conditions. For all carriers studied, the NH4+-N removal kinetics could be well simulated by the first-order model, and the NH4+-N and COD removal rates were logarithmically correlated with the carrier's specific surface area. Due to its high ammonia removal, stable performance and easy operation, the ceramsite-packed SBBR is feasible for MRAS water treatment.},
}
@article {pmid30937696,
year = {2019},
author = {Mi, L and Liu, Y and Wang, C and He, T and Gao, S and Xing, S and Huang, Y and Fan, H and Zhang, X and Yu, W and Mi, Z and Tong, Y and Bai, C and Han, F},
title = {Identification of a lytic Pseudomonas aeruginosa phage depolymerase and its anti-biofilm effect and bactericidal contribution to serum.},
journal = {Virus genes},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11262-019-01660-4},
pmid = {30937696},
issn = {1572-994X},
abstract = {Pseudomonas aeruginosa (P. aeruginosa) infection has imposed a great threat to patients with cystic fibrosis. With the emergence of multidrug-resistant P. aeruginosa, developing an alternative anti-microbial strategy is indispensable and more urgent than ever. In this study, a lytic P. aeruginosa phage was isolated from the sewage of a hospital, and one protein was predicted as the depolymerase-like protein by genomic sequence analysis, it includes two catalytic regions, the Pectate lyase_3 super family and Glycosyl hydrolase_28 super family. Further analysis demonstrated that recombinant depolymerase-like protein degraded P. aeruginosa exopolysaccharide and enhanced bactericidal activity mediated by serum in vitro. Additionally, this protein disrupted host bacterial biofilms. All of these results showed that the phage-derived depolymerase-like protein has the potential to be developed into an anti-microbial agent that targets P. aeruginosa.},
}
@article {pmid30936939,
year = {2019},
author = {Lu, L and Hu, W and Tian, Z and Yuan, D and Yi, G and Zhou, Y and Cheng, Q and Zhu, J and Li, M},
title = {Developing natural products as potential anti-biofilm agents.},
journal = {Chinese medicine},
volume = {14},
number = {},
pages = {11},
doi = {10.1186/s13020-019-0232-2},
pmid = {30936939},
issn = {1749-8546},
abstract = {Biofilm is a natural form of bacterial growth ubiquitously in environmental niches. The biofilm formation results in increased resistance to negative environmental influences including resistance to antibiotics and antimicrobial agents. Quorum sensing (QS) is cell-to-cell communication mechanism, which plays an important role in biofilm development and balances the environment when the bacteria density becomes high. Due to the prominent points of biofilms implicated in infectious disease and the spread of multi-drug resistance, it is urgent to discover new antibacterial agents that can regulate biofilm formation and development. Accumulated evidences demonstrated that natural products from plants had antimicrobial and chemo-preventive properties in modulation of biofilm formation in the last two decades. This review will summarize recent studies on the discovery of natural anti-biofilm agents from plants with clear-cut mechanisms or identified molecular addresses, as well as some herbs with unknown mechanisms or unidentified bioactive ingredients. We also focus on the progression of techniques on the extraction and identification of natural anti-biofilm substances. Besides, anti-biofilm therapeutics undergoing clinical trials are discussed. These newly discovered natural anti-biofilm agents are promising candidates which could provide novel strategies for biofilm-associated infections.},
}
@article {pmid30936487,
year = {2019},
author = {He, L and Le, KY and Khan, BA and Nguyen, TH and Hunt, RL and Bae, JS and Kabat, J and Zheng, Y and Cheung, GYC and Li, M and Otto, M},
title = {Resistance to leukocytes ties benefits of quorum sensing dysfunctionality to biofilm infection.},
journal = {Nature microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41564-019-0413-x},
pmid = {30936487},
issn = {2058-5276},
abstract = {Social interactions play an increasingly recognized key role in bacterial physiology1. One of the best studied is quorum sensing (QS), a mechanism by which bacteria sense and respond to the status of cell density2. While QS is generally deemed crucial for bacterial survival, QS-dysfunctional mutants frequently arise in in vitro culture. This has been explained by the fitness cost an individual mutant, a 'quorum cheater', saves at the expense of the community3. QS mutants are also often isolated from biofilm-associated infections, including cystic fibrosis lung infection4, as well as medical device infection and associated bacteraemia5-7. However, despite the frequently proposed use of QS blockers to control virulence8, the mechanisms underlying QS dysfunctionality during infection have remained poorly understood. Here, we show that in the major human pathogen Staphylococcus aureus, quorum cheaters arise exclusively in biofilm infection, while in non-biofilm-associated infection there is a high selective pressure to maintain QS control. We demonstrate that this infection-type dependence is due to QS-dysfunctional bacteria having a significant survival advantage in biofilm infection because they form dense and enlarged biofilms that provide resistance to phagocyte attacks. Our results link the benefit of QS-dysfunctional mutants in vivo to biofilm-mediated immune evasion, thus to mechanisms that are specific to the in vivo setting. Our findings explain why QS mutants are frequently isolated from biofilm-associated infections and provide guidance for the therapeutic application of QS blockers.},
}
@article {pmid30936159,
year = {2019},
author = {Fahmi, T and Faozia, S and Port, G and Cho, KH},
title = {The Second Messenger c-di-AMP Regulates Diverse Cellular Pathways Involved in Stress Response, Biofilm Formation, Cell Wall Homeostasis, SpeB Expression and Virulence in Streptococcus pyogenes.},
journal = {Infection and immunity},
volume = {},
number = {},
pages = {},
doi = {10.1128/IAI.00147-19},
pmid = {30936159},
issn = {1098-5522},
abstract = {Cyclic di-adenosine monophosphate (c-di-AMP) is a recently discovered second messenger in bacteria. The cellular level of c-di-AMP in S. pyogenes is predicted to be controlled by the synthase DacA and two putative phosphodiesterases, GdpP and Pde2. To investigate the role of c-di-AMP in S. pyogenes, we generated null mutants in each of these proteins by gene deletion. Unlike those in other Gram-positive pathogens such as Staphylcoccus aureus and Listeria monocytogenes, DacA in S. pyogenes was not essential for growth in rich media. The DacA null mutant presented a growth defect that manifested through increased lag time, produced no detectable biofilm, and displayed increased susceptibility towards environmental stressors such as high salts, low pH, reactive oxygen radicals, and cell wall targeting antibiotics, suggesting that c-di-AMP plays significant roles in crucial cellular processes involved in stress management. The Pde2 null mutant exhibited a slower growth rate and increased biofilm formation, and interestingly, these phenotypes were distinct from those of the null mutant of GdpP, suggesting that Pde2 and GdpP play distinctive roles in c-di-AMP homeostasis. DacA and Pde2 were critical to the production of the virulence factor SpeB, and to the overall virulence of S. pyogenes as both DacA and Pde2 null mutants were highly attenuated in a mouse model of subcutaneous infection. Collectively, c-di-AMP is an important global regulator and is required for proper response to stress and for virulence in S. pyogenes, suggesting that its signaling pathway could be an attractive anti-virulence drug target against S. pyogenes infections.},
}
@article {pmid30936108,
year = {2019},
author = {Usui, M and Yokoo, H and Tamura, Y and Nakajima, C and Suzuki, Y and Ghigo, JM and Beloin, C},
title = {Zinc acetate potentiates the action of tosufloxacin Escherichia coli biofilm persisters.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.00069-19},
pmid = {30936108},
issn = {1098-6596},
abstract = {Formation of bacterial biofilms is a major health threat due to their high levels of tolerance to multiple antibiotics and the presence of persisters responsible for infection relapses. We previously showed that combination of starvation and induction of SOS response in biofilm lead to increase levels of persisters and biofilm tolerance to fluoroquinolones. In this study, we hypothesized that inhibition of the SOS response may be an effective strategy to target biofilms and fluoroquinolone persister cells. We tested the survival of Escherichia coli biofilms to different classes of antibiotics in starved and non-starved conditions and in presence of zinc acetate, a SOS response inhibitor. We showed that zinc acetate potentiates, albeit moderately, the activity of fluoroquinolones against E. coli persisters in starved biofilms. The efficacy of zinc acetate to increase fluoroquinolone activity, particularly tosufloxacin, suggests that such a combination may be a potential strategy for treating biofilm-related bacterial infections.},
}
@article {pmid30935149,
year = {2019},
author = {Ma, Z and Bumunang, EW and Stanford, K and Bie, X and Niu, YD and McAllister, TA},
title = {Biofilm Formation by Shiga Toxin-Producing Escherichia coli on Stainless Steel Coupons as Affected by Temperature and Incubation Time.},
journal = {Microorganisms},
volume = {7},
number = {4},
pages = {},
doi = {10.3390/microorganisms7040095},
pmid = {30935149},
issn = {2076-2607},
support = {FOS.07.17//Beef Cattle Research Council To Agriculture and Agri-Food Canada and Alberta Agriculture and Forestry/ ; 0001//Chinese Ministry of Education/ ; },
abstract = {Forming biofilm is a strategy utilized by Shiga toxin-producing Escherichia coli (STEC) to survive and persist in food processing environments. We investigated the biofilm-forming potential of STEC strains from 10 clinically important serogroups on stainless steel at 22 °C or 13 °C after 24, 48, and 72 h of incubation. Results from crystal violet staining, plate counts, and scanning electron microscopy (SEM) identified a single isolate from each of the O113, O145, O91, O157, and O121 serogroups that was capable of forming strong or moderate biofilms on stainless steel at 22 °C. However, the biofilm-forming strength of these five strains was reduced when incubation time progressed. Moreover, we found that these strains formed a dense pellicle at the air-liquid interface on stainless steel, which suggests that oxygen was conducive to biofilm formation. At 13 °C, biofilm formation by these strains decreased (P < 0.05), but gradually increased over time. Overall, STEC biofilm formation was most prominent at 22 °C up to 24 h. The findings in this study identify the environmental conditions that may promote STEC biofilm formation in food processing facilities and suggest that the ability of specific strains to form biofilms contributes to their persistence within these environments.},
}
@article {pmid30934181,
year = {2019},
author = {Jirawatnotai, S and Mahachitsattaya, B},
title = {Analysis of subclinical infections and biofilm formation in cases of capsular contracture after silicone augmentation rhinoplasty: Prevalence and microbiological study.},
journal = {Archives of plastic surgery},
volume = {46},
number = {2},
pages = {160-166},
doi = {10.5999/aps.2018.00864},
pmid = {30934181},
issn = {2234-6163},
abstract = {BACKGROUND: Implant-related deformities in aesthetic rhinoplasty are a major problem for rhinoplasty surgeons. Capsular contracture is believed to be the pathological cause of delayed contour deformities, comparable to breast implant-related contracture. This study investigated the prevalence of bacterial biofilms and other epidemiological factors related to capsular contracture in cases of silicone augmentation rhinoplasty.<br><br>METHODS: Thirty-three patients who underwent corrective rhinoplasty due to a delayed contour deformity or aesthetic revision after implant rhinoplasty were studied from December 2014 to December 2016. All recruited patients received surgical correction by the authors. The patients were categorized by clinical severity into four grades. Demographic data and related confounding factors were recorded. Samples of capsular tissue and silicone removed from each patient were analyzed for the presence of a biofilm by ultrasonication with bacterial culture and scanning electron microscopy.<br><br>RESULTS: Thirty-three paired samples of capsular tissue and silicone implants from the study group were analyzed. Biofilms were detected in one of 10 subjects (10%) with grade 1 contracture, two of four (50%) with grade 2 contracture, 10 of 14 (71.40%) with grade 3 contracture, and four of five (80%) with grade 4 contracture (P<0.05). The organisms found were Staphylococcus epidermidis (47.10%), coagulase-negative staphylococci (35.30%), and Staphylococcus aureus (17.60%).<br><br>CONCLUSIONS: As with breast implant-related capsular contracture, silicone nasal augmentation deformities likely result from bacterial biofilms. We demonstrated the prevalence of biofilms in patients with various degrees of contracture. Implant type and operative technique seemed to have only vague correlations with biofilm presence.},
}
@article {pmid30933902,
year = {2019},
author = {Dige, I and Nyvad, B},
title = {Candida species in intact in vivo biofilm from carious lesions.},
journal = {Archives of oral biology},
volume = {101},
number = {},
pages = {142-146},
doi = {10.1016/j.archoralbio.2019.03.017},
pmid = {30933902},
issn = {1879-1506},
abstract = {OBJECTIVES: The aim of this study was to investigate the occurrence and spatial localization of Candida species in intact in vivo biofilm from caries lesions in root and occlusal surfaces.<br><br>MATERIALS AND METHODS: Biofilm from 7 teeth with root caries and 9 teeth with occlusal caries were analyzed. The teeth were fixed, embedded, sectioned and decalcified before fluorescence in situ hybridization using oligonucleotide probes against all bacteria (EUB338), all yeast (PF2), streptococci (STR405, MUT590) and C. albicans (Du.al 1249). Sections were analyzed using fluorescence microscopy.<br><br>RESULTS: Yeasts, most of which were C. albicans or C. dubliniensis, colonized occlusal and root surface sites and exhibited both yeast and hyphal forms. Two characteristic colonization patterns were apparent: In one pattern, the biofilm presented defined areas comprising Candida hyphal networks mixed with filamentous, rod-like and coccoid bacteria, often extending through the entire biofilm thickness. In the other pattern, Candida formed corncob configurations with non-mutans streptococci in the biofilm surface layer. Mutans streptococci formed isolated colonies and did not typically appear in close proximity with Candida.<br><br>CONCLUSION: For the first time, we showed that C. albicans and C. dubliniensis are integrated components of caries biofilm architecture. Co-localization of Candida and non-mutans streptococci indicates a beneficial interaction between these organisms. Diverse metabolic properties of Candida spp. suggest that these organisms may influence the ecology of cross-kingdom microbial communities in caries.},
}
@article {pmid30929087,
year = {2019},
author = {Zhang, LY and Fang, ZH and Li, QL and Cao, CY},
title = {A tooth-binding antimicrobial peptide to prevent the formation of dental biofilm.},
journal = {Journal of materials science. Materials in medicine},
volume = {30},
number = {4},
pages = {45},
doi = {10.1007/s10856-019-6246-6},
pmid = {30929087},
issn = {1573-4838},
abstract = {Dental caries is primarily caused by pathogenic bacteria infection, and Streptococcus mutans is considered a major cariogenic pathogen. Moreover, antimicrobial peptides have been considered an alternative to traditional antibiotics in treating caries. This study aimed to design a tooth-binding antimicrobial peptide and evaluate its antimicrobial efficacy against S. mutans. An antimicrobial peptide of polyphemusin I (PI) was modified by grafting a tooth-binding domain of diphosphoserine (Ser(p)-Ser(p)-) to create the peptide of Ser(p)-Ser(p)-polyphemusin I (DPS-PI). PI and DPS-PI were synthesized by Fmoc solid-phase peptide synthesis. The minimum inhibitory concentration of PI and DPS-PI against S. mutans were tested. Scanning electron microscopy (SEM) were used to observe the growth of S. mutans on PI and DPS-PI treated enamel surfaces. The growth of S. mutans was evaluated by optical density (OD) at 590 nm. Inhibition of dental plaque biofilm development in vivo were investigated. The cytocompatibility to bone mesenchymal stem cells (BMSCs) was tested. The MIC of PI and DPS-PI were 40 and 80 μg/ml, respectively. SEM images showed that S. mutans were sparsely distributed on the DPS-PI treated enamel surface. OD findings indicated that DPS-PI maintained its inhibition effect on S. mutans growth after 24 h. The incisor surfaces of rabbits treated with DPS-PI developed significantly less dental plaque biofilm than that on PI treated surfaces. The DPS-PI had good biocompatibility with the cells. We successfully constructed a novel tooth-binding antimicrobial peptide against S. mutans in vitro and inhibited dental plaque biofilm development in vivo. DPS-PI may provide a feasible alternative to conventional antibiotics for the prevention and treatment of dental caries. Dental caries is primarily caused by pathogenic bacteria infection, and Streptococcus mutans is considered a major cariogenic pathogen. A tooth-binding antimicrobial peptide was designed by grafted diphosphoserine (-Ser(p)-Ser(p)-) to the structure of polyphemusin I. This novel tooth-binding antimicrobial peptide can inhibit dental plaque biofilm development and thus provide a feasible alternative to conventional antibiotics for the prevention and treatment of dental caries.},
}
@article {pmid30928423,
year = {2019},
author = {Lin, MF and Lin, YY and Lan, CY},
title = {A method to assess influence of different medical tubing on biofilm formation by Acinetobacter baumannii.},
journal = {Journal of microbiological methods},
volume = {160},
number = {},
pages = {84-86},
doi = {10.1016/j.mimet.2019.03.023},
pmid = {30928423},
issn = {1872-8359},
abstract = {In this study, we developed a method to assess influence of different medical tubing on biofilm formation by A. baumannii. The results of biofilm quantification and scanning electron microscopy showed that the biofilm formation susceptibility of different tubing materials was rubber latex > polyvinyl chloride > silicone.},
}
@article {pmid30927751,
year = {2019},
author = {Roila, R and Ranucci, D and Valiani, A and Galarini, R and Servili, M and Branciari, R},
title = {Antimicrobial and anti-biofilm activity of olive oil by-products against Campylobacter spp. isolated from chicken meat.},
journal = {Acta scientiarum polonorum. Technologia alimentaria},
volume = {18},
number = {1},
pages = {43-52},
doi = {10.17306/J.AFS.0629},
pmid = {30927751},
issn = {1898-9594},
abstract = {BACKGROUND: Worldwide, poultry is considered the main source of food-related human campylobacteriosis, which is generally associated with the consumption of raw or undercooked chicken meat. Furthermore, Cam- pylobacter develops biofilms that are resistant to environmental stress, antibiotics, and disinfectants and are becoming a major issue for the food industry, especially the poultry industry. This study investigated the antimicrobial and anti-biofilm properties of polyphenols found in spray-dried olive mill wastewater (OMWW--SD) against Campylobacter strains isolated from chicken meat.<br><br>METHODS: OMWW-SD was produced by dehydration of olive mill wastewater polyphenolic extract. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for OMWW-SD were determined by microdilution method whereas the inhibitory effect of the OMWW-SD on biofilm formation and biofilm disaggregation was tested through crystal violet assay on polystyrene plates.<br><br>RESULTS: The phenolic profile of OMWW-SD mainly consisted of secoiridoid and hydroxycinnamic acid derivatives. Oleuropein-aglycone di-aldehyde (a secoiridoid derivative) was the major constituent, representing 72.5% of the total identified phenolic compounds. OMWW-SD showed a MIC ranging from 0.15 mg/mL to 0.3 mg/mL and a MBC of 0.3 mg/mL for all Campylobacter strains tested. The olive by-product extract tested was able, in vitro, to inhibit biofilm formation and to promote biofilm dispersion even at sub-MIC concentra- tions, with values ranging from 6% to 92% and from 4% to 83% at varying extract dilutions, respectively.<br><br>CONCLUSIONS: OMWW-SD could be developed as a new anti-biofilm agent with potential to control Campylo- bacter in the food chain, especially in the poultry industry, thereby enhancing food safety.},
}
@article {pmid30927638,
year = {2019},
author = {Wei, Z and Yu, S and Huang, Z and Xiao, X and Tang, M and Li, B and Zhang, X},
title = {Simultaneous removal of elemental mercury and NO by mercury induced thermophilic community in membrane biofilm reactor.},
journal = {Ecotoxicology and environmental safety},
volume = {176},
number = {},
pages = {170-177},
doi = {10.1016/j.ecoenv.2019.03.082},
pmid = {30927638},
issn = {1090-2414},
abstract = {Thermophilic membrane biofilm reactor (TMBR) for elemental mercury (Hg0) and NO removal in simulated flue gas was investigated at oxygen content of 6% and 60 °C. The performance, the microbial community structures, gene function and the mechanism for Hg0 and NO removal in the TMBR were evaluated. TMBR achieved effective simultaneous Hg0 and NO removal in 210 days of operation, Hg0 and NO removal efficiency were up to 88.9% and 85.3%, respectively. Mercury induced thermophilic community had been formed significantly. Comamonas, Pseudomonas, Desulfomicrobium, Burkholderia and Halomonas were thermophilic mercury resistant bacteria. Brucella, Paracoccus, Tepidiphilus, Proteobacteria, Pseudomonas and Symbiobacterium were nitrifying/denitrifying genera, and had functional genes of mercury and nitrogen metabolism, as shown by16S rDNA and metagenomic sequencing. The biofilm in TMBR was characterized by XPS, HPLC. XPS and HPLC spectra indicate the formation of a mercuric species (Hg2+) from mercury oxidation. TMBR used oxygen as electron acceptor, NO and Hg0 as electron donor in nitrification; O2, NO and NO3- could be used as electron acceptor and Hg0 as electron donor in denitrification.},
}
@article {pmid30927492,
year = {2019},
author = {Patel, A and Carlson, RP and Henson, MA},
title = {In silico Metabolic Design of Two-strain Biofilm Systems Predicts Enhanced Biomass Production and Biochemical Synthesis.},
journal = {Biotechnology journal},
volume = {},
number = {},
pages = {e1800511},
doi = {10.1002/biot.201800511},
pmid = {30927492},
issn = {1860-7314},
abstract = {Engineered biofilm consortia have the potential to solve important biotechnological problems that have proved difficult for monoculture biofilms and planktonic consortia such as conversion of lignocellulosic material to useful biochemicals. While considerable experimental progress has been reported for engineering and characterizing biofilm consortia, the field still lacks in silico tools for simulation, design and optimization of stable, robust and productive designed consortia. We developed biofilm consortia metabolic models for two coculture systems centered around the ecological design motif of a primary cell type that utilizes a supplied electron donor and secretes acetate as a byproduct and a secondary cell type that consumes the acetate relieving byproduct inhibition on the primary cell type and enhancing overall system biomass. Our models predicted that distinct metabolic niches for the two cell types could be established by supplying electron donors and acceptors at opposite ends of the biofilm and that acetate consumption by the secondary cell type could increase total biomass accumulation and the synthesis of valuable biochemicals such as isobutanol by the primary cell type. System tunability was enhanced when each cell type was supplied with a unique terminal electron acceptor at opposite ends of the biofilm rather than competing for a common electron acceptor. Our model provided good qualitative agreement with data for a synthetic E. coli coculture system, suggesting that the proposed design rules may have wide applicability to engineered biofilm consortia. This article is protected by copyright. All rights reserved.},
}
@article {pmid30927413,
year = {2019},
author = {Aziz, K and Tariq, M and Zaidi, A},
title = {Biofilm development in L. fermentum under shear flow &amp; sequential GIT digestion.},
journal = {FEMS microbiology letters},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsle/fnz064},
pmid = {30927413},
issn = {1574-6968},
abstract = {The objective of this study was to investigate biofilm formation by Lactobacillus fermentum under physiologically relevant shear conditions both in the presence and absence of a food matrix and under simulated conditions of digestion. This was done using batch and flow biofilms of L. fermentum strains under conditions simulating digestion in the human gastrointestinal tract and shear flow using a high throughput platform BioFlux 1000Z system. The putative probiotic strain, PL29, was found to be capable of adhesion and biofilm formation in mucin-coated microfluidic channels under liquid flow conditions mimicking those of the GIT. Based on these in vitro measurements, we conclude that L. fermentum strain PL29 could be an effective probiotic for human consumption.},
}
@article {pmid30926526,
year = {2019},
author = {Patel, KK and Tripathi, M and Pandey, N and Agrawal, AK and Gade, S and Anjum, MM and Tilak, R and Singh, S},
title = {Alginate lyase immobilized chitosan nanoparticles of ciprofloxacin for the improved antimicrobial activity against the biofilm associated mucoid P. aeruginosa infection in cystic fibrosis.},
journal = {International journal of pharmaceutics},
volume = {563},
number = {},
pages = {30-42},
doi = {10.1016/j.ijpharm.2019.03.051},
pmid = {30926526},
issn = {1873-3476},
abstract = {Dense colonization of mucoid Pseudomonas aeruginosa within the self-secreted extracellular matrix (mainly alginate), called biofilm, is a principal reason for the failure of antimicrobial therapy in cystic fibrotic patients. Alginate is a key component in the biofilm of mucoid P. aeruginosa and responsible for surface adhesion and stabilization of biofilm. To overcome this problem, alginate lyase functionalized chitosan nanoparticles of ciprofloxacin were developed for the effective treatment of P. aeruginosa infection in cystic fibrosis patients. The developed nanoparticles were found to have desired quality attributes and demonstrated sustained release following the Higuchi release kinetics. Drug compatibility with the chitosan was confirmed by FTIR while powder X-ray diffraction analysis confirmed the entrapment of drug within the nanoparticle matrix. Lactose adsorbed NPs showed promising aerodynamic property. Nanoparticles showed prolonged MIC and significant reduction in biofilm aggregation and formation in planktonic bacterial suspension. Nanoparticles exhibited significantly higher inhibitory effect against biofilm of P. aeruginosa and reduced the biomass, thickness and density confirmed by confocal microscopy. Furthermore, developed nanoparticles were haemocompatible and did not exhibit any toxicity in vitro MTT assay and in vivo on lungs male Wistar rats. The data in hand collectively suggest the proposed strategy a better alternative for the effective treatment of cystic fibrosis infections.},
}
@article {pmid30924805,
year = {2019},
author = {Sandip, M and Kalyanraman, V},
title = {Enhanced simultaneous nitri-denitrification in aerobic moving bed biofilm reactor containing polyurethane foam-based carrier media.},
journal = {Water science and technology : a journal of the International Association on Water Pollution Research},
volume = {79},
number = {3},
pages = {510-517},
doi = {10.2166/wst.2019.077},
pmid = {30924805},
issn = {0273-1223},
abstract = {Fluidization of carrier media for biofilm support and growth defines the moving bed biofilm reactor (MBBR) process. Major MBBR facilities apply virgin polyethylene (PE)-based circular plastic carrier media. Various carriers were studied to replace these conventional carriers, but polyurethane (PU) foam-based carrier media has not been much explored. This study evaluates the potential of PU foam carrier media in aerobic MBBR process for simultaneous nitri-denitrification (SND). Two parallel reactors loaded with conventional PE plastic (circular) and PU foam (cubical) carriers compared for their removal efficiencies of chemical oxygen demand (COD) and nitrogen contaminants from wastewater. Results indicate that average COD removal in MBBR containing PE plastic carrier media was 81%, compared to 83% in MBBR containing PU foam. Average ammonical and total nitrogen reduction was 71% and 59% for PU foam-based MBBR, compared to 60% and 42% for PE plastic-based MBBR. SND-based nitrogen removal capacity was doubled in aerobic MBBR filled with PU foam carrier media (27%), than MBBR containing PE plastic carrier media (13%). Cost economics also governs the commercial advantage for the application of PU foam-based carrier media in the MBBR process.},
}
@article {pmid30924795,
year = {2019},
author = {Metcalf, D and Bowler, PG},
title = {Perceptions of Wound Biofilm by Wound Care Clinicians.},
journal = {Wounds : a compendium of clinical research and practice},
volume = {31},
number = {3},
pages = {E14-E17},
pmid = {30924795},
issn = {1943-2704},
abstract = {OBJECTIVE: The aim of this study was to gain a greater understanding of the perceptions of wound biofilm held by wound care clinicians.<br><br>METHODS: Independent market research was conducted in the United States and Europe via an online questionnaire to understand the knowledge levels of wound biofilm among clinicians.<br><br>RESULTS: Clinicians from the United States appeared most knowledgeable on the subject of wound biofilm, though there was a wider consensus that biofilm contributes to delayed wound healing. A number of visual and indirect clinical signs for the presence of wound biofilm were commonly listed by all clinicians. In this study, and others, widespread calls for further education on wound biofilm, in addition to anti-biofilm and diagnostic technologies, were made.<br><br>CONCLUSIONS: This study has contributed to the global call to focus on tackling biofilm for the benefit of wound care patients, caregivers, and health care systems.},
}
@article {pmid30924535,
year = {2019},
author = {Silva, AF and Dos Santos, AR and Trevisan, DAC and Bonin, E and Freitas, CF and Batista, AFP and Hioka, N and Simões, M and Graton Mikcha, JM},
title = {Xanthene Dyes and Green LED for the Inactivation of Foodborne Pathogens in Planktonic and Biofilm States.},
journal = {Photochemistry and photobiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/php.13104},
pmid = {30924535},
issn = {1751-1097},
abstract = {This study evaluated the rose bengal- and erythrosine-mediated photoinactivation against Salmonella Typhimurium and Staphylococcus aureus planktonic and sessile cells using green LED as a light source. The free-living or 2-day-old biofilm cells were treated with different concentrations of the photosensitizing agents and subjected to irradiation. Only 5 min photosensitization with rose bengal at 25 nmol L-1 and 75 μmol L-1 completely eliminated S. aureus and S. Typhimurium planktonic cells, respectively. Erythrosine at 500 nmol L-1 and 5 min of light exposure also reduced S. aureus planktonic cells to undetectable levels. Eradication of S. aureus biofilms was achieved when 500 μmol L-1 of erythrosine or 250 μmol L-1 of rose bengal was combined with 30 min of irradiation. Scanning electron microscopy allowed the observation of morphological changes in planktonic cells and disruption of the biofilm architecture after photodynamic treatment. The overall data demonstrate that rose bengal and erythrosine activated by green LED may be a targeted strategy for controlling foodborne pathogens in both planktonic and sessile states.},
}
@article {pmid30917333,
year = {2019},
author = {Mardanpour, MM and Saadatmand, M and Yaghmaei, S},
title = {Interpretation of the electrochemical response of a multi-population biofilm in a microfluidic microbial fuel cell using a comprehensive model.},
journal = {Bioelectrochemistry (Amsterdam, Netherlands)},
volume = {128},
number = {},
pages = {39-48},
doi = {10.1016/j.bioelechem.2019.03.003},
pmid = {30917333},
issn = {1878-562X},
abstract = {The present study investigates the diversification and dynamic behavior of a multi-population microfluidic microbial fuel cell (MFC) as a biosensor. The cost effective microfluidic MFC coupled to a comprehensive model, presents a novel platform for monitoring chemical and biological phenomena. The importance of competition among different microbial groups, hierarchical biochemical processes, bacterial chemotaxis and different mechanisms of electron transfer were significant considerations in the present model. The validation of the model using experimental data from a microfluidic MFC shows an appropriate match with the hierarchal biodegradation processes of a complex substrate as well as development of bacterial chemotaxis during multi-population biofilm formation under real conditions. Microfluidic MFC performance, including temporal and spatial distribution of different microbial group concentrations in the biofilm and anolyte bulk, the competitive behavior of different species, bacterial transport parameters and bioelectrochemical characteristics are also assessed.},
}
@article {pmid30917172,
year = {2019},
author = {Chatterjee, S and Biswas, N and Datta, A and Maiti, PK},
title = {Periodicities in the roughness and biofilm growth on glass substrate with etching time: Hydrofluoric acid etchant.},
journal = {PloS one},
volume = {14},
number = {3},
pages = {e0214192},
doi = {10.1371/journal.pone.0214192},
pmid = {30917172},
issn = {1932-6203},
abstract = {Adherence of the microorganism to submerged solid surfaces leads to biofilm formation. Biofilm formation modifies the surfaces in favor of bacteria facilitating the survival of the bacteria under different stressed conditions. On the other hand, the formation of biofilm has a direct adverse economic impact in various industries and more importantly in medical practices. This adherence is the reason for the failure of many indwelling medical devices. Surface biofilm adhesion is the key to biofilm growth and stability. Hence this adhesion needs to be substantially lowered to inhibit biofilm stability. Both chemical and physical properties of the surface influence biofilm formation and modulating these properties can control this formation. In this study, we have investigated the effect of Hydrofluoric acid (HF), at a specific concentration as an etchant, on the surface morphology of substrates and the growth of biofilms of Pseudomonas aeruginosa. and Staphylococcus aureus. We find that the bacterial counts on the etched surfaces undergo a periodic increase and decrease. This, on one hand, shows the close correlation between the biofilm growth and the particular roughness scale, and on the other hand, explains the existing contradictory results regarding the effects of etching on substrate roughness and biofilm growth. We propose a simple model of a sequence of hole formation, hole expansion and etching away of the hole walls to form a new, comparatively smooth surface, coupled with the preferential accumulation of bacteria at the hole edges, to explain these periodicities.},
}
@article {pmid30915345,
year = {2019},
author = {Zannier, F and Portero, LR and Ordoñez, OF and Martinez, LJ and Farías, ME and Albarracin, VH},
title = {Polyextremophilic Bacteria from High Altitude Andean Lakes: Arsenic Resistance Profiles and Biofilm Production.},
journal = {BioMed research international},
volume = {2019},
number = {},
pages = {1231975},
doi = {10.1155/2019/1231975},
pmid = {30915345},
issn = {2314-6141},
abstract = {High levels of arsenic present in the High Altitude Andean Lakes (HAALs) ecosystems selected arsenic-resistant microbial communities which are of novel interest to study adaptations mechanisms potentially useful in bioremediation processes. We herein performed a detailed characterization of the arsenic tolerance profiles and the biofilm production of two HAAL polyextremophiles, Acinetobacter sp. Ver3 (Ver3) and Exiguobacterium sp. S17 (S17). Cellular adherence over glass and polypropylene surfaces were evaluated together with the effect of increasing doses and oxidative states of arsenic over the quality and quantity of their biofilm production. The arsenic tolerance outcomes showed that HAAL strains could tolerate higher arsenic concentrations than phylogenetic related strains belonging to the German collection of microorganisms and cell cultures (Deutsche Sammlung von Mikroorganismen und Zellkulturen, DSMZ), which suggest adaptations of HAAL strains to their original environment. On the other hand, the crystal violet method (CV) and SEM analysis showed that Ver3 and S17 were able to attach to solid surfaces and to form the biofilm. The quantification of biofilms production in 48 hours' cultures through CV shows that Ver3 yielded higher production in the treatment without arsenic cultured on a glass support, while S17 yield higher biofilm production under intermediate arsenic concentration on glass supports. Polypropylene supports had negative effects on the biofilm production of Ver3 and S17. SEM analysis shows that the highest biofilm yields could be associated with a larger number of attached cells as well as the development of more complex 3D multicellular structures.},
}
@article {pmid30914689,
year = {2019},
author = {Naranjo, E and Merfa, MV and Ferreira, V and Jain, M and Davis, MJ and Bahar, O and Gabriel, DW and De La Fuente, L},
title = {Liberibacter crescens biofilm formation in vitro: establishment of a model system for pathogenic 'Candidatus Liberibacter spp.'.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {5150},
doi = {10.1038/s41598-019-41495-5},
pmid = {30914689},
issn = {2045-2322},
support = {2016-70016-24844//United States Department of Agriculture | National Institute of Food and Agriculture (NIFA)/ ; 2016-70016-24844//United States Department of Agriculture | National Institute of Food and Agriculture (NIFA)/ ; 2016-70016-24844//United States Department of Agriculture | National Institute of Food and Agriculture (NIFA)/ ; IS-4841-15 F//United States - Israel Binational Agricultural Research and Development Fund (BARD)/ ; IS-4841-15 F//United States - Israel Binational Agricultural Research and Development Fund (BARD)/ ; },
abstract = {The Liberibacter genus comprises insect endosymbiont bacterial species that cause destructive plant diseases, including Huanglongbing in citrus and zebra chip in potato. To date, pathogenic 'Candidatus Liberibacter spp.' (CLs) remain uncultured, therefore the plant-associated Liberibacter crescens (Lcr), only cultured species of the genus, has been used as a biological model for in vitro studies. Biofilm formation by CLs has been observed on the outer midgut surface of insect vectors, but not in planta. However, the role of biofilm formation in the life cycle of these pathogens remains unclear. Here, a model system for studying CLs biofilms was developed using Lcr. By culture media modifications, bovine serum albumin (BSA) was identified as blocking initial cell-surface adhesion. Removal of BSA allowed for the first time observation of Lcr biofilms. After media optimization for biofilm formation, we demonstrated that Lcr attaches to surfaces, and form cell aggregates embedded in a polysaccharide matrix both in batch cultures and under flow conditions in microfluidic chambers. Biofilm structures may represent excellent adaptive advantages for CLs during insect vector colonization helping with host retention, immune system evasion, and transmission. Future studies using the Lcr model established here will help in the understanding of the biology of CLs.},
}
@article {pmid30913464,
year = {2019},
author = {Abinaya, M and Gayathri, M},
title = {Inhibition of biofilm formation, quorum sensing activity and molecular docking study of isolated 3, 5, 7-Trihydroxyflavone from Alstonia scholaris leaf against P.aeruginosa.},
journal = {Bioorganic chemistry},
volume = {87},
number = {},
pages = {291-301},
doi = {10.1016/j.bioorg.2019.03.050},
pmid = {30913464},
issn = {1090-2120},
abstract = {The current study is to evaluate the inhibition of biofilm formation and quorum sensing activity of isolated 3, 5, 7-Trihydroxyflavone (TF) from A.scholaris leaf extract against Pseudomonas aeruginosa. The effects of isolated TF on quorum sensing-regulated virulence factors production such as swimming motility, pyocyanin production, proteolytic, EPS, metabolic assay and inhibition of biofilm formation against P.aeruginosa was evaluated by standard protocols. In addition, the interaction between the isolated TF and active sites of QS- gene (LasI/rhlI, LasR/rhlR, and AHLase) in P.aeruginosa was evaluated by molecular docking studies using AutoDock Tools version 1.5.6. Based on the structural elucidation of the isolated compound was identified as 3, 5, 7-Trihydroxyflavone. Consequently, the isolated TF shows a significant reduction of biofilm formation through the inhibition of QS-dependent phenotypes such as pyocyanin production, proteolytic, swimming motility, EPS activities against P.aeruginosa in a dose-dependent manner. Molecular docking analysis of isolated TF can interfere the signaling [N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12-HSL) and N-butanoyl-L-homoserine lactone (C4-HSL)] molecules in P.aeruginosa by QS genes (LasI, LasR, rhlI, and AHLase) regulation. The isolated TF compound from A.scholaris reveals a greater potential to inhibit biofilm and QS dependent virulence factor production in P.aeruginosa. Docking interaction studies of TF-LasR complex express higher binding affinity than the other QS gene in P.aeruginosa.},
}
@article {pmid30913433,
year = {2019},
author = {Montoya-Rosales, JJ and Olmos-Hernández, DK and Palomo-Briones, R and Montiel-Corona, V and Mari, AG and Razo-Flores, E},
title = {Improvement of continuous hydrogen production using individual and binary enzymatic hydrolysates of agave bagasse in suspended-culture and biofilm reactors.},
journal = {Bioresource technology},
volume = {283},
number = {},
pages = {251-260},
doi = {10.1016/j.biortech.2019.03.072},
pmid = {30913433},
issn = {1873-2976},
abstract = {Continuous hydrogen (H2) production from individual (Stonezyme, IH) and binary (Celluclast-Viscozyme, BH) enzymatic hydrolysates of agave bagasse was evaluated in continuous stirred-tank reactors (CSTR) and trickling bed reactors (TBR). The volumetric H2 production rates (VHPR) in CSTR were 13 and 2.25 L H2/L-d with BH and IH, respectively. Meanwhile, VHPR of 5.76 and 2.0 L H2/L-d were obtained in the TBR configuration using BH and IH, respectively. Differences on VHPR between reactors could be explained by substrate availability, which is intrinsic to the growth mode of each reactor configuration; while differences of VHPR between hydrolysates were possibly related to the composition of enzymatic hydrolysates. Furthermore, homoacetogenesis was strongly influenced by H2 and substrate transfer conditions. Considering VHPR, H2 yields, and costs of hydrolysis, hydrogen production from binary hydrolysates of agave bagasse was identified as the most promising alternative evaluated with scale-up potential for the production of energy biofuels.},
}
@article {pmid30912922,
year = {2019},
author = {Wang, Y and Kadiyala, U and Qu, Z and Elvati, P and Altheim, C and Kotov, NA and Violi, A and VanEpps, JS},
title = {Anti-Biofilm Activity of Graphene Quantum Dots via Self-Assembly with Bacterial Amyloid Proteins.},
journal = {ACS nano},
volume = {13},
number = {4},
pages = {4278-4289},
doi = {10.1021/acsnano.8b09403},
pmid = {30912922},
issn = {1936-086X},
abstract = {Bacterial biofilms represent an essential part of Earth's ecosystem that can cause multiple ecological, technological, and health problems. The environmental resilience and sophisticated organization of biofilms are enabled by the extracellular matrix that creates a protective network of biomolecules around the bacterial community. Current anti-biofilm agents can interfere with extracellular matrix production but, being based on small molecules, are degraded by bacteria and rapidly diffuse away from biofilms. Both factors severely reduce their efficacy, while their toxicity to higher organisms creates additional barriers to their practicality. In this paper, we report on the ability of graphene quantum dots to effectively disperse mature amyloid-rich Staphylococcus aureus biofilms, interfering with the self-assembly of amyloid fibers, a key structural component of the extracellular matrix. Mimicking peptide-binding biomolecules, graphene quantum dots form supramolecular complexes with phenol-soluble modulins, the peptide monomers of amyloid fibers. Experimental and computational results show that graphene quantum dots efficiently dock near the N-terminus of the peptide and change the secondary structure of phenol-soluble modulins, which disrupts their fibrillation and represents a strategy for mitigation of bacterial communities.},
}
@article {pmid30911404,
year = {2019},
author = {Greener, J},
title = {On the nature of &quot;skeletal&quot; biofilm patterns, &quot;hidden&quot; heterogeneity and the role of bubbles to reveal them.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {12},
doi = {10.1038/s41522-019-0085-6},
pmid = {30911404},
issn = {2055-5008},
abstract = {A short communication on the recent paper by Jang et al. discusses the role of &quot;mushroom&quot; structures and effects of nearly static bubbles on nascent biofilms.},
}
@article {pmid30911403,
year = {2019},
author = {El-Awady, A and de Sousa Rabelo, M and Meghil, MM and Rajendran, M and Elashiry, M and Stadler, AF and Foz, AM and Susin, C and Romito, GA and Arce, RM and Cutler, CW},
title = {Polymicrobial synergy within oral biofilm promotes invasion of dendritic cells and survival of consortia members.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {11},
doi = {10.1038/s41522-019-0084-7},
pmid = {30911403},
issn = {2055-5008},
support = {R01 DE014328/DE/NIDCR NIH HHS/United States ; },
abstract = {Years of human microbiome research have confirmed that microbes rarely live or function alone, favoring diverse communities. Yet most experimental host-pathogen studies employ single species models of infection. Here, the influence of three-species oral microbial consortium on growth, virulence, invasion and persistence in dendritic cells (DCs) was examined experimentally in human monocyte-derived dendritic cells (DCs) and in patients with periodontitis (PD). Cooperative biofilm formation by Streptococcus gordonii, Fusobacterium nucleatum and Porphyromonas gingivalis was documented in vitro using growth models and scanning electron microscopy. Analysis of growth rates by species-specific 16s rRNA probes revealed distinct, early advantages to consortium growth for S. gordonii and F. nucleatum with P. gingivalis, while P. gingivalis upregulated its short mfa1 fimbriae, leading to increased invasion of DCs. F. nucleatum was only taken up by DCs when in consortium with P. gingivalis. Mature consortium regressed DC maturation upon uptake, as determined by flow cytometry. Analysis of dental plaques of PD and healthy subjects by 16s rRNA confirmed oral colonization with consortium members, but DC hematogenous spread was limited to P. gingivalis and F. nucleatum. Expression of P. gingivalis mfa1 fimbriae was increased in dental plaques and hematogenous DCs of PD patients. P. gingivalis in the consortium correlated with an adverse clinical response in the gingiva of PD subjects. In conclusion, we have identified polymicrobial synergy in a three-species oral consortium that may have negative consequences for the host, including microbial dissemination and adverse peripheral inflammatory responses.},
}
@article {pmid30910809,
year = {2019},
author = {Korir, ML and Dale, JL and Dunny, GM},
title = {Role of epaQ, a previously uncharacterized Enterococcus faecalis gene, in biofilm development and antimicrobial resistance.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00078-19},
pmid = {30910809},
issn = {1098-5530},
abstract = {Enterococcus faecalis is a commensal of the human gastrointestinal tract; it is also an opportunistic pathogen and one of the leading causes of hospital-acquired infections. E. faecalis produces biofilms that are highly resistant to antibiotics and it has been previously reported that certain genes of the epa operon contribute to biofilm-associated antibiotic resistance. Despite several studies examining the epa operon, many gene products of this operon remain annotated as hypothetical proteins. Here we further explore the epa operon; we identified epaQ, currently annotated as encoding a hypothetical membrane protein, as important for biofilm formation in the presence of the antibiotic daptomycin. Mutants with disruptions of epaQ were more susceptible to daptomycin relative to the wild type, suggesting its importance in biofilm-associated antibiotic resistance. Furthermore, ΔepaQ exhibited an altered biofilm architectural arrangement and formed small aggregates in liquid cultures. Our cumulative data show that epa mutations result in altered polysaccharide content, increased cell-surface hydrophobicity and decreased membrane potential. Surprisingly, several epa mutations significantly increased resistance to the antibiotic ceftriaxone, indicating that the way in which the epa operon impacts antibiotic resistance is antibiotic dependent. These results further define the key role of epa in antibiotic resistance in biofilms and in biofilm architecture.ImportanceE. faecalis is a common cause of nosocomial infection, has a high-level of antibiotic resistance, and forms robust biofilms. Biofilm formation is associated with increased antibiotic resistance. Therefore, a thorough understanding of biofilm-associated antibiotic resistance is important for combating resistance. Several genes from the epa operon have previously been implicated in biofilm-associated antibiotic resistance, pathogenesis and competitive fitness in the GI tract, but most genes in this locus remain uncharacterized. Here we examine epaQ, which has not been characterized functionally. We show that ΔepaQ exhibits reduced biofilm formation in the presence of daptomycin, altered biofilm architecture, and increased resistance to ceftriaxone, further expanding our understanding of the contribution of this operon to intrinsic enterococcal antibiotic resistance and biofilm growth.},
}
@article {pmid30909644,
year = {2019},
author = {Wijesundara, NM and Rupasinghe, HPV},
title = {Bactericidal and Anti-Biofilm Activity of Ethanol Extracts Derived from Selected Medicinal Plants against Streptococcus pyogenes.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {6},
pages = {},
doi = {10.3390/molecules24061165},
pmid = {30909644},
issn = {1420-3049},
support = {CRDPJ 448052//Natural Sciences and Engineering Research Council of Canada/ ; },
abstract = {Background: There is a growing interest in medicinal plants which have been traditionally used for the treatment of human infections. This study assessed 14 ethanol extracts (EEs) on bacterial growth and biofilm formation of Streptococcus pyogenes. Methods: Constituent major phytochemicals in the extracts were identified using ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS). Micro-broth dilution and time-kill assays were used to determine antibacterial activities. Anti-biofilm activities were studied using MTT assay, and morphology of biofilms was observed by scanning electron microscopy (SEM). Transmission electron microscopy (TEM) was employed to visualize the ultra-cross section structure of bacteria treated with efficacious extracts. Results: Licorice root, purple coneflower flower, purple coneflower stem, sage leaves and slippery elm inner bark EEs were the most effective, with minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of 62.5 μg/mL and 125 μg/mL, respectively. The minimum biofilm inhibitory concentration (MBIC) of extracts ranged from 31.5⁻250 μg/mL. Morphological changes were observed in treated biofilms compared to the untreated. The four most effective extracts exhibited the ability to induce degradation of bacterial cell wall and disintegration of the plasma membrane. Conclusion: We suggest that EEs of sage leaf and purple coneflower flower are promising candidates to be further investigated for developing alternative natural therapies for the management of streptococcal pharyngitis.},
}
@article {pmid30909573,
year = {2019},
author = {Lagha, R and Ben Abdallah, F and Al-Sarhan, BO and Al-Sodany, Y},
title = {Antibacterial and Biofilm Inhibitory Activity of Medicinal Plant Essential Oils Against Escherichia coli Isolated from UTI Patients.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {6},
pages = {},
doi = {10.3390/molecules24061161},
pmid = {30909573},
issn = {1420-3049},
abstract = {Urinary tract infections (UTIs), caused by Escherichia coli 80% to 85% of the time, are one of the most important causes of morbidity and health care spending affecting persons of all ages. These infections lead to many difficult problems, especially increasing resistance to antibiotic drugs. Bacterial biofilms play an important role in UTIs, responsible for persistent infections leading to recurrences and relapses. In this study, we have investigated the antibacterial activity of five medicinal plant essential oils against UTIs caused by E. coli using disc diffusion and minimal inhibition concentration (MIC) methods. In addition, biofilm inhibitory action of oils was realized by crystal violet. Gas chromatography⁻mass spectrometry (GC⁻MS) analysis showed a variability between oils in terms of compound numbers as well as their percentages. Antibacterial activity was observed only in cases of Origanum majorana, Thymus zygis and Rosmarinus officinalis, while Juniperus communis and Zingiber officinale did not showed any effect towards E. coli isolates. T. zygis essential oil demonstrated the highest antibacterial activity against E. coli isolates, followed by O. majorana and R. officinalis. Further, oils showed high biofilm inhibitory action with a percentage of inhibition that ranged from 14.94% to 94.75%. R. officinalis oil had the highest antibiofilm activity followed by T. zygis and O. majorana. Accordingly, tested oils showed very effective antibacterial and antibiofilm activities against E. coli UTIs and can be considered as good alternative for antibiotics substitution.},
}
@article {pmid30909069,
year = {2019},
author = {Méndez-Tovar, M and García-Meza, JV and González, I},
title = {Electrochemical monitoring of Acidithiobacillus thiooxidans biofilm formation on graphite surface with elemental sulfur.},
journal = {Bioelectrochemistry (Amsterdam, Netherlands)},
volume = {128},
number = {},
pages = {30-38},
doi = {10.1016/j.bioelechem.2019.03.004},
pmid = {30909069},
issn = {1878-562X},
abstract = {Inorganic wastewaters and sediments from the mining industry and mineral bioleaching processes have not been fully explored in bioelectrochemical systems (BES). Knowledge of interfacial changes due to biofilm evolution under acidic conditions may improve applications in electrochemical processes, specifically those related to sulfur compounds. Biofilm evolution of Acidithiobacillus thiooxidans on a graphite plate was monitored by electrochemical techniques, using the graphite plate as biofilm support and elemental sulfur as the only energy source. Even though the elemental sulfur was in suspension, S0 particles adhered to the graphite surface favoring biofilm development. The biofilms grown at different incubation times (without electric perturbation) were characterized in a classical three electrode electrochemical cell (sulfur and bacteria free culture medium) by non-invasive electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. The biofilm structure was confirmed by Environmental Scanning Electrode Microscopy, while the relative fractions of exopolysaccharides and extracellular hydrophobic compounds at different incubation times were evaluated by Confocal Laser Scanning Microscopy. The experimental conditions chosen in this work allowed the EIS monitoring of the biofilm growth as well as the modification of Extracellular Polymeric Substances (EPS) composition (hydrophobic/ exopolysaccharides EPS ratio). This strategy could be useful to control biofilms for BES operation under acidic conditions.},
}
@article {pmid30908986,
year = {2019},
author = {Zheng, Z and Huang, S and Bian, W and Liang, D and Wang, X and Zhang, K and Ma, X and Li, J},
title = {Enhanced nitrogen removal of the simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm reactor for treating mainstream wastewater under low dissolved oxygen (DO) concentration.},
journal = {Bioresource technology},
volume = {283},
number = {},
pages = {213-220},
doi = {10.1016/j.biortech.2019.01.148},
pmid = {30908986},
issn = {1873-2976},
abstract = {The simultaneous partial nitrification, anammox and denitrification (SNAD) process for treating mainstream wastewater was investigated under different intermittent aeration modes. By controlling the aeration time of 20, 60 and 180 min during the intermittent modes, the oxygen concentration remained 3.50, 1.45 and 0.70 mg·L-1. Correspondingly, the reactor achieved the nitrogen removal rate of 0.17, 0.29 and 0.30 kg N·m-3·d-1. Meanwhile, the average total inorganic nitrogen (TIN) removal efficiency reached 93.4%, 87.5% and 92.7%. The effluent NO3--N concentration was very low. High-throughput sequencing analysis indicated that the proportion of nitrite oxidization bacteria (NOB), anammox bacteria and denitrification bacteria was 0.15%, 0.33% and 8.78%. Candidatus Anammoxoglobus was the abundant anammox bacteria genus. Further study on the unclassified sequences revealed the possibility of the high relative abundance of Nitrosomonas-related genus and Candidatus Kuenenia-related genus on the SNAD biofilm.},
}
@article {pmid30908836,
year = {2019},
author = {Alrabiah, M and Alshagroud, RS and Alsahhaf, A and Almojaly, SA and Abduljabbar, T and Javed, F},
title = {Presence of Candida species in the subgingival oral biofilm of patients with peri-implantitis.},
journal = {Clinical implant dentistry and related research},
volume = {},
number = {},
pages = {},
doi = {10.1111/cid.12760},
pmid = {30908836},
issn = {1708-8208},
support = {RG-1438-075//College of Dentistry, King Saud University/ ; },
abstract = {BACKGROUND: There are no studies that have investigated the presence of Candida species in the subgingival oral biofilm (OB) of patients with peri-implantitis.<br><br>PURPOSE: The aim was to assess the presence of Candida species in the subgingival OB of patients with peri-implantitis.<br><br>MATERIALS AND METHODS: Individuals with (group A) and without (group B) peri-implantitis were included. Life style related and demographic data were collected using a questionnaire. In both groups, peri-implant plaque-index (PI), bleeding-on-probing (BOP), and probing-depth (PD) were evaluated and crestal bone loss (CBL) were measured on digital bitewing radiographs. In both groups, subgingival OB samples were collected using sterile paper points. Identification of Candida species was performed using ChromAgar medium and colony forming units per milliliter (CFU/mL) were determined. Statistical analysis was performed, and level of significance was set at P < 0.05.<br><br>RESULTS: The mean age of individuals in groups A (n = 43) and B (n = 41) were 52.2 ± 4.4 and 55.1 ± 2.3 years, respectively. All participants were male. In groups A and B, implants were in function for 7.4 ± 1.3 and 6.8 ± 0.6 years, respectively. Scores of peri-implant PI (P < 0.001), BOP (P < 0.001), PD (P < 0.001), and CBL (P < 0.001) were significantly higher in group A than group B. Subgingival Candida was isolated from the OB of 33 (76.7%) patients in group A and 5 (12.2%) individuals in group B. The most common yeast species was Candida albicans, which was isolated from 67.4% to 60% individuals in groups A and B, respectively. The number of subgingival oral yeasts CFU/mL were significantly higher in group A (3147.54 ± 1052.6 CFU/mL) compared with group B (496.68 ± 100.2 CFU/mL; P < 0.01).<br><br>CONCLUSION: Candida species (predominantly C. albicans) are present in the subgingival OB of patients with peri-implantitis. Community-based efforts toward routine oral hygiene maintenance are needed to improve oral health and minimize the risks of peri-implant diseases in populations.},
}
@article {pmid30905995,
year = {2019},
author = {Malhotra, R and Dhawan, B and Garg, B and Shankar, V and Nag, TC},
title = {A Comparison of Bacterial Adhesion and Biofilm Formation on Commonly Used Orthopaedic Metal Implant Materials: An In vitro Study.},
journal = {Indian journal of orthopaedics},
volume = {53},
number = {1},
pages = {148-153},
doi = {10.4103/ortho.IJOrtho_66_18},
pmid = {30905995},
issn = {0019-5413},
abstract = {Background: Bacterial adherence and biofilm formation on the surface of biomaterials can often lead to implant-related infections, which may vary depending on the species of microorganisms, type of biomaterial used, and physical characteristics of implant surfaces. However, there are limited studies specifically comparing biofilm formation between commonly used metallic orthopaedic implant materials and different bacterial strains. This in vitro study is to evaluate the ability of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa to adhere to and to form biofilms on the surface of five orthopaedic biomaterials, viz., cobalt and chromium, highly cross-linked polyethylene, stainless steel, trabecular metal, and titanium alloy.<br><br>Materials and Methods: Bacterial adherence and bacterial biofilm-formation assays were performed by culturing S. aureus ATCC 29213, S. epidermidis ATCC 35984, E. coli ATCC 35218, K. pneumoniae ATCC 700603, and P. aeruginosa ATCC 27853 for 48 h on five different biomaterials. Quantitative bacterial adherence and biofilm formation were analyzed with a scanning electron microscope.<br><br>Results: The highest level of adherence was observed on highly cross-linked polyethylene, followed by titanium, stainless steel, and trabecular metal, with the lowest occurring on the cobalt-chromium alloy. Among the bacterial strains tested, the ability for high adherence was observed with S. epidermidis and K. pneumoniae followed by P. aeruginosa and E. coli, whereas S. aureus showed the least adherence.<br><br>Conclusion: Cobalt-chromium was observed to have the lowest proclivity towards bacterial adherence compared to the other biomaterials tested. However, bacterial adhesion occurred with all the materials. Hence, it is necessary to further evaluate newer biomaterials that are resistant to bacterial adherence.},
}
@article {pmid30903821,
year = {2019},
author = {Hossain, MI and Cheng, L and Cord-Ruwisch, R},
title = {Energy efficient COD and N-removal from high-strength wastewater by a passively aerated GAO dominated biofilm.},
journal = {Bioresource technology},
volume = {283},
number = {},
pages = {148-158},
doi = {10.1016/j.biortech.2019.03.056},
pmid = {30903821},
issn = {1873-2976},
abstract = {Conventional aerobic treatment of high-strength wastewater is not economical due to excessively high energy requirement for compressed air supply. The use of passive aeration avoids the use of compressed air and enables energy efficient oxygen supply directly from the air. This study evaluates a passively aerated simultaneous nitrification and denitrification performing biofilm to treat concentrated wastewater. The biofilm reactor was operated > 5-months under alternating anaerobic/aerobic conditions. For 4-times concentrated wastewater, > 80% COD (2307 mg L-1 h-1) and > 60% N (60 mg L-1 h-1) was removed at a hydraulic retention time (HRT) of 7 h. A double application in the same reactor enabled > 95% COD and 85% N-removal, at an overall HRT of 14 h which is substantially shorter than what traditional activated sludge-based systems would require for the treatment of such concentrated feeds. Microbial community analysis showed Candidatus competibacter (27%) and nitrifying bacteria (Nitrosomonas, and Nitrospira) as key microbes involved in COD and N-removal, respectively.},
}
@article {pmid30902863,
year = {2019},
author = {Rondeau, M and Esmaeel, Q and Crouzet, J and Blin, P and Gosselin, I and Sarazin, C and Pernes, M and Beaugrand, J and Wisniewski-Dyé, F and Vial, L and Faure, D and Clément, C and Ait Barka, E and Jacquard, C and Sanchez, L},
title = {Biofilm constructing variants of Paraburkholderia phytofirmans PsJN outcompete the wild-type form in free-living and static conditions but not in planta.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.02670-18},
pmid = {30902863},
issn = {1098-5336},
abstract = {Members of the genus Burkholderia colonize diverse ecological niches. Among the plant-associated strains, Paraburkholderia phytofirmans PsJN is an endophyte with a broad host range. In spatially structured environment (unshaken broth cultures), biofilm-constructing specialists of P. phytofirmans PsJN colonizing the air-liquid interface arose at high frequency. In addition to forming a robust biofilm in vitro and in planta on Arabidopsis roots, those mucoid phenotypic variants display a reduced swimming ability and modulate the expression of several Microbe Associated Molecular Pattern (MAMPs) including exopolysaccharides (EPS), flagellin and GroEL. Interestingly, the variants induce a low PR1 and PDF1.2 expression compared to the parental strain, suggesting a possible evasion of plant host immunity. We further demonstrated that switching from the planktonic to the sessile form did not involve quorum-sensing genes but arose from spontaneous mutations in two genes belonging to an Iron-Sulfur Cluster: hscA (encoding a co-chaperone protein) and iscS (encoding a cysteine desulfurase). A mutational approach validated the implication of these two genes in the appearance of variants. We showed for the first time that in heterogeneous environment, P. phytofirmans strain PsJN is able to rapidly diversify and co-express a variant that outcompete the wild-type form in free-living and static conditions but not in plantaIMPORTANCEParaburkholderia phytofirmans strain PsJN is a well-studied plant-associated bacterium known to induce resistance against biotic and abiotic stresses. In this work, we described the spontaneaous appearance of mucoid variants in PsJN from static cultures. We showed that the conversion from wild-type (WT) form to variants (V) correlates with an overproduction of EPS, an enhanced ability to form biofilm in vitro and in planta and a reduced swimming motility. Our results revealed also that these phenotypes are in part associated with spontaneaous mutations in an Iron-Sulfur Cluster. Overall, the data provided here allowed a better understanding of the adaptive mechanisms likely developed by P. phytofirmans PsJN in heterogeneous environment.},
}
@article {pmid30901676,
year = {2019},
author = {Jovanovic, M and Radivojevic, J and O'Connor, K and Blagojevic, S and Begovic, B and Lukic, V and Nikodinovic-Runic, J and Savic, V},
title = {Rhamnolipid inspired lipopeptides effective in preventing adhesion and biofilm formation of Candida albicans.},
journal = {Bioorganic chemistry},
volume = {87},
number = {},
pages = {209-217},
doi = {10.1016/j.bioorg.2019.03.023},
pmid = {30901676},
issn = {1090-2120},
abstract = {Rhamnolipids are biodegradable low toxic biosurfactants which exert antimicrobial and anti-biofilm properties. They have attracted much attention recently due to potential applications in areas of bioremediation, therapeutics, cosmetics and agriculture, however, the full potential of these versatile molecules is yet to be explored. Based on the facts that many naturally occurring lipopeptides are potent antimicrobials, our study aimed to explore the potential of replacing rhamnose in rhamnolipids with amino acids thus creating lipopeptides that would mimic or enhance properties of the parent molecule. This would allow not only for more economical and greener production but also, due to the availability of structurally different amino acids, facile manipulation of physico-chemical and biological properties. Our synthetic efforts produced a library of 43 lipopeptides revealing biologically more potent molecules. The structural changes significantly increased, in particular, anti-biofilm properties against Candida albicans, although surface activity of the parent molecule was almost completely abolished. Our findings show that the most active compounds are leucine derivatives of 3-hydroxy acids containing benzylic ester functionality. The SAR study demonstrated a further increase in activity with aliphatic chain elongation. The most promising lipopeptides 15, 23 and 36 at 12.5 µg/mL concentration allowed only 14.3%, 5.1% and 11.2% of biofilm formation, respectively after 24 h. These compounds inhibit biofilm formation by preventing adhesion of C. albicans to abiotic and biotic surfaces.},
}
@article {pmid30900762,
year = {2019},
author = {Velmourougane, K and Prasanna, R and Chawla, G and Nain, L and Kumar, A and Saxena, AK},
title = {Trichoderma-Azotobacter biofilm inoculation improves soil nutrient availability and plant growth in wheat and cotton.},
journal = {Journal of basic microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1002/jobm.201900009},
pmid = {30900762},
issn = {1521-4028},
support = {//Indian Council of Agricultural Research (ICAR) Network Project on Microorganisms &quot;Application of Microorganisms in Agricultural and Allied Sectors&quot; (AMAAS)/ ; },
abstract = {Microbial biofilms are gaining importance in agriculture, due to their multifaceted agronomic benefits and resilience to environmental fluctuations. This study focuses on comparing the influence of single inoculation-Azotobacter chroococcum (Az) or Trichoderma viride (Tv) and their biofilm (Tv-Az), on soil and plant metabolic activities in wheat and cotton grown under Phytotron conditions. Tv-Az proved superior to all the other treatments in terms of better colonisation, plant growth attributes and 10-40% enhanced availability of macronutrients and micronutrients in the soil, over control. Confocal and scanning electron microscopy showed that the cells attached to the root tips initially, followed by their proliferation along the surface of the roots. Soil polysaccharides, proteins and dehydrogenase activity showed several fold enhancement in Tv-Az biofilm inoculated samples. Time course studies revealed that the population of Az and Tv in the rhizoplane and rhizosphere was significantly higher with a 0.14-0.31 log colony-forming unit (CFU) increase in the biofilm-inoculated treatment in both crops. Enhancement in soil biological activities was facilitated by the improved colonisation of the biofilm, due to the synergistic association between Tv and Az. This demonstrates the utility of Tv-Az biofilm as a multifunctional plant growth promoting and soil fertility enhancing option in agriculture.},
}
@article {pmid30895679,
year = {2019},
author = {Robinson, VH and Paterson, S and Bennett, C and Steen, SI},
title = {Biofilm production of Pseudomonas spp. isolates from canine otitis in three different enrichment broths.},
journal = {Veterinary dermatology},
volume = {},
number = {},
pages = {},
doi = {10.1111/vde.12738},
pmid = {30895679},
issn = {1365-3164},
support = {//Dechra Veterinary Products, Hadnall, Shropshire, UK/ ; },
abstract = {BACKGROUND: Pseudomonas spp. are commonly isolated from dogs with clinical otitis and have been shown to produce biofilm. There is a paucity of studies demonstrating biofilm growth in veterinary medicine.<br><br>HYPOTHESIS/OBJECTIVES: To compare biofilm production of Pseudomonas spp. isolated from dogs with otitis using three different enrichment broths at two different time points. Speciation was performed.<br><br>ANIMALS: One hundred isolates from 98 animals with clinical otitis were assessed for biofilm production.<br><br>METHODS AND MATERIALS: One hundred isolates were assessed for biofilm production using a microtitre plate assay. Biofilm production in Luria-Bertani Broth (LBB), Mueller-Hinton Broth (MHB) and Tryptic Soy Broth (TSB) were assessed after 18 and 24 h of incubation.<br><br>RESULTS: At 18 h, biofilm production was demonstrated in 87% of LBB, 91% of TSB and 93% of MHB grown isolates. By 24 h, this was 92% of LBB, 96% of TSB and 99% of MHB isolates. Biofilm production was significantly increased after 24 h incubation compared to 18 h. A significant difference was noted in biofilm production between LBB and MHB (P = 0.0349), but not between LBB and TSB (P = 0.3727) or MHB and TSB (P = 0.3687) at 24 h incubation. Two isolates were speciated as P. fluorescens and 98 as P. aeruginosa.<br><br>Not all enrichment broths were equivalent with one another and 24 h incubation was superior to 18 h. Presence of a biofilm is likely in otic Pseudomonas spp. isolates.},
}
@article {pmid30895659,
year = {2019},
author = {Maillard, JY and McBain, A},
title = {Biofilm in healthcare settings and their control.},
journal = {Letters in applied microbiology},
volume = {68},
number = {4},
pages = {268},
doi = {10.1111/lam.13147},
pmid = {30895659},
issn = {1472-765X},
}
@article {pmid30895626,
year = {2019},
author = {Sterniša, M and Klančnik, A and Smole Možina, S},
title = {Spoilage Pseudomonas biofilm with Escherichia coli protection in fish meat at 5 °C.},
journal = {Journal of the science of food and agriculture},
volume = {},
number = {},
pages = {},
doi = {10.1002/jsfa.9703},
pmid = {30895626},
issn = {1097-0010},
support = {P4-0116//Slovenian Research Agency/ ; },
abstract = {BACKGROUND: Pseudomonas are part of the indigenous microbiota of different foods, where they gradually cause spoilage. In fish meat, Pseudomonas fragi and Pseudomonas psychrophila have been identified as important spoilers. The initial aim of this study was to investigate the physiological characteristics, adhesion, and biofilm of P. fragi and P. psychrophila under temperatures related to the fish-processing industry. The further aim was to define the problem of increased growth of pathogenic bacteria in the presence of spoilage bacteria in vitro and in fish meat.<br><br>RESULTS: Temperature dependence on physiological characteristics, adhesion, and biofilm was observed. Hydrophobicity and autoaggregation were most prominent at 15 °C, and at this temperature floating biofilm was also formed. The adhesion of these Pseudomonas was up to 2 log CFU cm-1 more pronounced on stainless steel than polystyrene, with up to five times greater biofilm biomass production at 5 °C on polystyrene. This paralleled at least a 0.5 log CFU g-1 increase in the pathogenic bacterium Escherichia coli in fish meat.<br><br>CONCLUSION: Pseudomonas fragi and P. psychrophila adhesion and biofilm depend on the temperature, and are stimulated by temperatures that can occur during the processing and storage of fish meat. Strong Pseudomonas biofilm formation under refrigeration conditions is protective for E. coli, potentially by providing more favorable conditions by ensuring a higher concentration of nutrients. Interactions between spoilage Pseudomonas and pathogenic bacteria can occur through different mechanisms, and an understanding of these is of particular importance to ensure the overall quality and safety of fish meat and other proteinaceous foods. © 2019 Society of Chemical Industry.},
}
@article {pmid30894842,
year = {2019},
author = {Yang, J and Cheng, S and Li, C and Sun, Y and Huang, H},
title = {Shear Stress Affects Biofilm Structure and Consequently Current Generation of Bioanode in Microbial Electrochemical Systems (MESs).},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {398},
doi = {10.3389/fmicb.2019.00398},
pmid = {30894842},
issn = {1664-302X},
abstract = {Shear stress is an important factor that affects the formation and structure of anode biofilms, which are strongly related to the extracellular electron transfer phenomena and bioelectric performance of bioanodes. Here, we show that using nitrogen sparging to induce shear stress during anode biofilm formation increases the linear sweep voltammetry peak current density of the mature anode biofilm from 2.37 ± 0.15 to 4.05 ± 0.25 A/m2. Electrochemical impedance spectroscopy results revealed that the shear-stress-enriched anode biofilm had a low charge transfer resistance of 46.34 Ω compared to that of the unperturbed enriched anode biofilm (72.2 Ω). Confocal laser scanning microscopy observations showed that the shear-stress-enriched biofilms were entirely viable, whereas the unperturbed enriched anode biofilm consisted of a live outer layer covering a dead inner-core layer. Based on biomass and community analyses, the shear-stress-enriched biofilm had four times the biofilm density (136.0 vs. 27.50 μg DNA/cm3) and twice the relative abundance of Geobacteraceae (over 80 vs. 40%) in comparison with those of the unperturbed enriched anode biofilm. These results show that applying high shear stress during anode biofilm enrichment can result in an entirely viable and dense biofilm with a high relative abundance of exoelectrogens and, consequently, better performance.},
}
@article {pmid30894675,
year = {2019},
author = {Zhao, T and Zhang, J and Tang, M and Ma, LZ and Lei, X},
title = {Development of an effective fluorescence probe for discovery of aminopeptidase inhibitors to suppress biofilm formation.},
journal = {The Journal of antibiotics},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41429-019-0166-z},
pmid = {30894675},
issn = {0021-8820},
abstract = {The human pathogen Pseudomonas aeruginosa can easily form biofilms. The extracellular matrix produced by the bacterial cells acts as a physical barrier to hinder the antibiotics treatment. It is necessary to destroy the biofilm in order to improve the efficacy of antibiotics. However, it has been a significant challenge to develop effective small molecules targeting the components of biofilm matrix. In this study, we report the development of a new effective fluorescence probe that could be used in the high throughput screening to identify novel small molecule inhibitors targeting the most abundant component in the biofilm formation: P. aeruginosa aminopeptidase (PaAP). Through screening of an in-house chemical library, a commercially available drug, balsalazide, has been identified as a novel PaAP inhibitor, which exhibited remarkable anti-biofilm effect. Our study indicated that the newly developed fluorescence probe is applicable in exploring new aminopeptidase inhibitors, and it also warrants further investigation of balsalazide as a new anti-biofilm agent to treat P. aeruginosa infection in combination with known antibiotics.},
}
@article {pmid30893371,
year = {2019},
author = {Morgan, SJ and Lippman, SI and Bautista, GE and Harrison, JJ and Harding, CL and Gallagher, LA and Cheng, AC and Siehnel, R and Ravishankar, S and Usui, ML and Olerud, JE and Fleckman, P and Wolcott, RD and Manoil, C and Singh, PK},
title = {Bacterial fitness in chronic wounds appears to be mediated by the capacity for high-density growth, not virulence or biofilm functions.},
journal = {PLoS pathogens},
volume = {15},
number = {3},
pages = {e1007511},
doi = {10.1371/journal.ppat.1007511},
pmid = {30893371},
issn = {1553-7374},
support = {R01 AI101307/AI/NIAID NIH HHS/United States ; K24 HL102246/HL/NHLBI NIH HHS/United States ; //Canadian Institutes for Health Research/International ; },
abstract = {While much is known about acute infection pathogenesis, the understanding of chronic infections has lagged. Here we sought to identify the genes and functions that mediate fitness of the pathogen Pseudomonas aeruginosa in chronic wound infections, and to better understand the selective environment in wounds. We found that clinical isolates from chronic human wounds were frequently defective in virulence functions and biofilm formation, and that many virulence and biofilm formation genes were not required for bacterial fitness in experimental mouse wounds. In contrast, genes involved in anaerobic growth, some metabolic and energy pathways, and membrane integrity were critical. Consistent with these findings, the fitness characteristics of some wound impaired-mutants could be represented by anaerobic, oxidative, and membrane-stress conditions ex vivo, and more comprehensively by high-density bacterial growth conditions, in the absence of a host. These data shed light on the bacterial functions needed in chronic wound infections, the nature of stresses applied to bacteria at chronic infection sites, and suggest therapeutic targets that might compromise wound infection pathogenesis.},
}
@article {pmid30891135,
year = {2019},
author = {Zhang, J and Huang, H and Zhou, X and Xu, Y and Chen, B and Tang, W and Xu, K},
title = {N-Benzylanilines as Fatty Acid Synthesis Inhibitors against Biofilm-related Methicillin-resistant Staphylococcus aureus.},
journal = {ACS medicinal chemistry letters},
volume = {10},
number = {3},
pages = {329-333},
doi = {10.1021/acsmedchemlett.8b00612},
pmid = {30891135},
issn = {1948-5875},
abstract = {Bacterial fatty acid synthase system is a well validated target for the development of novel antimicrobial agents. This study reports the synthesis of Schiff bases and their reductive N-benzylanilines. Most N-benzylanilines were active against Gram-positive bacteria, among which compound 4k performed best against both S. aureus and MRSA with the MIC value at 0.5 mg/L. Moreover, we identified the strong antibacterial activity for compound 4k against 19 clinical MRSA strains isolated from different specimen, which indicated its potential in clinical application. In vitro biofilm inhibition and microscopy assay revealed compound 4k inhibits biofilm formation and eradicates preformed biofilm effectively. The size-exclusion chromatography and docking study indicated that compound 4k mimics the binding mode of triclosan with saFabI. The efficiency of the protein-inhibitor interaction was evaluated by measuring NADPH reduction using trans-2-octenoyl-CoA as substrate. Overall, our data demonstrate that N-benzylaniline is a promising scaffold for anti-staphylococcal drug development.},
}
@article {pmid30891026,
year = {2019},
author = {Sigurlásdóttir, S and Wassing, GM and Zuo, F and Arts, M and Jonsson, AB},
title = {Deletion of D-Lactate Dehydrogenase A in Neisseria meningitidis Promotes Biofilm Formation Through Increased Autolysis and Extracellular DNA Release.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {422},
doi = {10.3389/fmicb.2019.00422},
pmid = {30891026},
issn = {1664-302X},
abstract = {Neisseria meningitidis is a Gram-negative bacterium that asymptomatically colonizes the human nasopharyngeal mucosa. Pilus-mediated initial adherence of N. meningitidis to the epithelial mucosa is followed by the formation of three-dimensional aggregates, called microcolonies. Dispersal from microcolonies contributes to the transmission of N. meningitidis across the epithelial mucosa. We have recently discovered that environmental concentrations of host cell-derived lactate influences N. meningitidis microcolony dispersal. Here, we examined the ability of N. meningitidis mutants deficient in lactate metabolism to form biofilms. A lactate dehydrogenease A (ldhA) mutant had an increased level of biofilm formation. Deletion of ldhA increased the N. meningitidis cell surface hydrophobicity and aggregation. In this study, we used FAM20, which belongs to clonal complex ST-11 that forms biofilms independently of extracellular DNA (eDNA). However, treatment with DNase I abolished the increased biofilm formation and aggregation of the ldhA-deficient mutant, suggesting a critical role for eDNA. Compared to wild-type, the ldhA-deficient mutant exhibited an increased autolytic rate, with significant increases in the eDNA concentrations in the culture supernatants and in biofilms. Within the ldhA mutant biofilm, the transcription levels of the capsule, pilus, and bacterial lysis genes were downregulated, while norB, which is associated with anaerobic respiration, was upregulated. These findings suggest that the absence of ldhA in N. meningitidis promotes biofilm formation and aggregation through autolysis-mediated DNA release.},
}
@article {pmid30888063,
year = {2019},
author = {Mostafavi, SKS and Najar-Peerayeh, S and Mobarez, AM and Parizi, MK},
title = {Characterization of uropathogenic E. coli O25b-B2-ST131, O15:K52:H1, and CGA: Neutrophils apoptosis, serum bactericidal assay, biofilm formation, and virulence typing.},
journal = {Journal of cellular physiology},
volume = {},
number = {},
pages = {},
doi = {10.1002/jcp.28459},
pmid = {30888063},
issn = {1097-4652},
support = {211356//Tarbiat Modares University/ ; },
abstract = {Pathogenic and drug-resistant strains of Escherichia coli (E. coli) O25b-B2-ST131, O15:H1-D-ST393, and CGA (clonal group A) clonal groups have spread worldwide. This study aimed at determining E. coli epidemic clonal groups, their virulence factors, biofilm formation, neutrophils apoptosis, and antimicrobial resistance pattern of uropathogenic E. coli. A total of 95 CTX-M-1-producing E. coli clinical isolates were enrolled. E. coli O25b-B2-ST131, CGA, and O15:K52:H1 were identified by serotyping and phylogrouping and allele-specific polymerase chain reaction-based assay. Antibiotic susceptibility, biofilm formation, hemolysis, and human serum bactericidal assay were performed. Neutrophil apoptosis was assayed by flow cytometry. Nine E. coli clonal groups including six O25b-B2-ST131 strains, two CGA, and one O15:K52:H1-D-ST393 strains were detected. One O25b-B2-ST131 isolate was a strong biofilm-producer. Three ST131 isolates had type I fimbriae. Furthermore, all the CGA and O15:K52:H1 and three of ST131 isolates harbored the P fimbriae. The virulence genes ompT, fimH, and traT were detected among all the clonal groups. The apoptosis was induced by O25b-B2-ST131, CGA, and O15:K52:H1 E. coli. There was no significant difference regarding apoptosis induction among clonal groups. Furthermore, the presence of the cdt, usp, and vat genes was significantly associated with the apoptosis of neutrophils by O25b-B2-ST131, CGA, and O15:K52:H1-D-ST393 clonal groups.},
}
@article {pmid30887260,
year = {2019},
author = {Rajamohamed, BS and Siddharthan, S},
title = {Modulatory effects of Amukkara Choornam on Candida albicans biofilm: in vitro and in vivo study.},
journal = {Molecular biology reports},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11033-019-04757-z},
pmid = {30887260},
issn = {1573-4978},
support = {YSS/20l4/000127//Science and Engineering Research Board/ ; },
abstract = {In the present study, Amukkara Chooram (AC) a well known herbal medicine was investigated for their antibiofilm efficacy against biofilm of Candida albicans. The biofilm inhibitory concentration of 20 µg/mL of AC showed promising effect by inhibiting the biofilm upto 60%. Morphogenic transition state of C. albicans from yeast cells to hyphal transition was prevented by AC was revealed from light microscopic images. In addition, the inhibition of yeast hyphae was examined in the induction medium supplemented with AC. Consequently, atomic force microscope (AFM) also documented the morphological changes observed during the transition state of C. albicans in the presence and absence of AC. Furthermore, scanning electron microscope (SEM) and confocal laser scanning microscopic (CLSM) images showed reduction in the biomass and thickness of the mature biofilm of C. albicans. In vivo investigation of C. albicans with zebrafish infection model presented the clearance of biofilm from the epithelium of the intestinal tissues. Later, the histological changes in liver and kidney due to C. albicans infection open up that treatment with AC was able to significantly rejuvenate the tissues. Altogether, the study presents AC as potent antibiofilm agent with potential ability as alternative medicine to treat C. albicans biofilm mediated infections.},
}
@article {pmid30887082,
year = {2019},
author = {Ciszek-Lenda, M and Strus, M and Walczewska, M and Majka, G and Machul-Żwirbla, A and Mikołajczyk, D and Górska, S and Gamian, A and Chain, B and Marcinkiewicz, J},
title = {Pseudomonas aeruginosa biofilm is a potent inducer of phagocyte hyperinflammation.},
journal = {Inflammation research : official journal of the European Histamine Research Society ... [et al.]},
volume = {68},
number = {5},
pages = {397-413},
doi = {10.1007/s00011-019-01227-x},
pmid = {30887082},
issn = {1420-908X},
support = {2017/27/B/NZ6/001772//Narodowe Centrum Nauki/ ; NN401547040//Narodowe Centrum Nauki/ ; },
abstract = {OBJECTIVE: Pseudomonas aeruginosa effectively facilitate resistance to phagocyte killing by biofilm formation. However, the cross talk between biofilm components and phagocytes is still unclear. We hypothesize that a biofilm provides a concentrated extracellular source of LPS, DNA and exopolysaccharides (EPS), which polarize neighbouring phagocytes into an adverse hyperinflammatory state of activation.<br><br>METHODS: We measured the release of a panel of mediators produced in vitro by murine neutrophils and macrophages exposed to various biofilm components of P. aeruginosa cultures.<br><br>RESULTS: We found that conditioned media from a high biofilm-producing strain of P. aeruginosa, PAR5, accumulated high concentrations of extracellular bacterial LPS, DNA and EPS by 72 h. These conditioned media induced phagocytes to release a hyperinflammatory pattern of mediators, with enhanced levels of TNF-α, IL-6, IL12p40, PGE2 and NO. Moreover, the phagocytes also upregulated COX-2 and iNOS with no influence on the expression of arginase-1.<br><br>CONCLUSIONS: Phagocytes exposed to biofilm microenvironment, called by us biofilm-associated neutrophils/macrophages (BANs/BAMs), display secretory properties similar to that of N1/M1-type phagocytes. These results suggest that in vivo high concentrations of LPS and DNA, trapped in biofilm by EPS, might convert infiltrating phagocytes into cells responsible for tissue injury without direct contact with bacteria and phagocytosis.},
}
@article {pmid30886729,
year = {2019},
author = {Okaro, U and Green, R and Mohapatra, S and Anderson, B},
title = {The trimeric autotransporter adhesin BadA is required for in vitro biofilm formation by Bartonella henselae.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {10},
doi = {10.1038/s41522-019-0083-8},
pmid = {30886729},
issn = {2055-5008},
abstract = {Bartonellahenselae (Bh) is a Gram-negative rod transmitted to humans by a scratch from the common house cat. Infection of humans with Bh can result in a range of clinical diseases including lymphadenopathy observed in cat-scratch disease and more serious disease from persistent bacteremia. It is a common cause of blood-culture negative endocarditis as the bacterium is capable of growing as aggregates, and forming biofilms on infected native and prosthetic heart valves. The aggregative growth requires a trimeric autotransporter adhesin (TAA) called Bartonella adhesin A (BadA). TAAs are found in all Bartonella species and many other Gram-negative bacteria. Using Bh Houston-1, Bh Houston-1 ∆badA and Bh Houston-1 ∆badA/pNS2PTrcbadA (a partial complement of badA coding for a truncated protein of 741 amino acid residues), we analyze the role of BadA in adhesion and biofilm formation. We also investigate the role of environmental factors such as temperature on badA expression and biofilm formation. Real-time cell adhesion monitoring and electron microscopy show that Bh Houston-1 adheres and forms biofilm more efficiently than the Bh Houston-1 ∆badA. Deletion of the badA gene significantly decreases adhesion, the first step in biofilm formation in vitro, which is partially restored in Bh Houston-1 ∆badA/pNS2PTrcbadA. The biofilm formed by Bh Houston-1 includes polysaccharides, proteins, and DNA components and is susceptible to enzymatic degradation of these components. Furthermore, both pH and temperature influence both badA expression and biofilm formation. We conclude that BadA is required for optimal adhesion, agglutination and biofilm formation.},
}
@article {pmid30886318,
year = {2019},
author = {Brislawn, CJ and Graham, EB and Dana, K and Ihardt, P and Fansler, SJ and Chrisler, WB and Cliff, JB and Stegen, JC and Moran, JJ and Bernstein, HC},
title = {Forfeiting the priority effect: turnover defines biofilm community succession.},
journal = {The ISME journal},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41396-019-0396-x},
pmid = {30886318},
issn = {1751-7370},
abstract = {Microbial community succession is a fundamental process that affects underlying functions of almost all ecosystems; yet the roles and fates of the most abundant colonizers are often poorly understood. Does early abundance spur long term persistence? How do deterministic and stochastic processes influence the ecological contribution of colonizers? We performed a succession experiment within a hypersaline ecosystem to investigate how different processes contributed to the turnover of founder species. Bacterial and eukaryotic colonizers were identified during primary succession and tracked through a defined, 79-day biofilm maturation period using 16S and 18S rRNA gene sequencing in combination with high resolution imaging that utilized stable isotope tracers to evaluate successional patterns of primary producers and nitrogen fixers. The majority of the founder species did not maintain high abundance throughout succession. Species replacement (versus loss) was the dominant process shaping community succession. We also asked if different ecological processes acted on bacteria versus Eukaryotes during succession and found deterministic and stochastic forces corresponded more with microeukaryote and bacterial colonization, respectively. Our results show that taxa and functions belonging to different kingdoms, which share habitat in the tight spatial confines of a biofilm, were influenced by different ecological processes and time scales of succession.},
}
@article {pmid30886168,
year = {2019},
author = {Nakamura, K and Shirato, M and Tenkumo, T and Kanno, T and Westerlund, A and Örtengren, U and Sasaki, K and Niwano, Y},
title = {Hydroxyl radicals generated by hydrogen peroxide photolysis recondition biofilm-contaminated titanium surfaces for subsequent osteoblastic cell proliferation.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {4688},
doi = {10.1038/s41598-019-41126-z},
pmid = {30886168},
issn = {2045-2322},
support = {16K20531//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; 15H05033//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; },
abstract = {Titanium dental implants have been successfully used for decades; however, some implants are affected by peri-implantitis due to bacterial infection, resulting in loss of supporting bone. This study aimed to evaluate the effect of an antimicrobial chemotherapy employing H2O2 photolysis-developed to treat peri-implantitis-on biofilm-contaminated titanium surfaces in association with osteoblastic cell proliferation on the treated surface. Titanium discs were sandblasted and acid-etched, followed by contamination with a three-species biofilm composed of Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus mitis. This biofilm model was used as a simplified model of clinical peri-implantitis biofilm. The discs were subjected to ultrasound scaling, followed by H2O2 photolysis, wherein 365-nm LED irradiation of the disc immersed in 3% H2O2 was performed for 5 min. We analysed proliferation of mouse osteoblastic cells (MC3T3-E1) cultured on the treated discs. Compared with intact discs, biofilm contamination lowered cell proliferation on the specimen surface, whereas H2O2 photolysis recovered cell proliferation. Thus, H2O2 photolysis can recover the degraded biocompatibility of biofilm-contaminated titanium surfaces and can potentially be utilised for peri-implantitis treatment. However, to verify the findings of this study in relation to clinical settings, assessment using a more clinically relevant multi-species biofilm model is necessary.},
}
@article {pmid30885396,
year = {2019},
author = {Ferreira, RBR and Ferreira, MCS and Glatthardt, T and Silvério, MP and Chamon, RC and Salgueiro, VC and Guimarães, LC and Alves, ES and Dos Santos, KRN},
title = {Osmotic stress induces biofilm production by Staphylococcus epidermidis isolates from neonates.},
journal = {Diagnostic microbiology and infectious disease},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.diagmicrobio.2019.02.009},
pmid = {30885396},
issn = {1879-0070},
abstract = {Staphylococcus epidermidis is one of the leading causes of bloodstream infections, particularly in premature neonates, and biofilm formation is a major virulence factor. We characterized biofilm formation by 50 S. epidermidis neonatal isolates under osmotic stress and evaluated the expression of biofilm-associated genes. Phenotypical analyses of biofilm production were performed in culture medium with or without addition of NaCl or glucose. In control medium (no additions), most isolates (84%) were nonproducers or weak biofilm producers. Growth in NaCl-containing medium increased the number of moderate/strong producers, and this increase was even greater in medium containing glucose. Most of the protein-enriched biofilms (60%) could be observed only during growth in glucose, whereas 50% of the polysaccharide-enriched biofilms were observed during growth in NaCl. Studies that evaluate the conditions used to characterize biofilm production are important to help us understand the dynamics of this important virulence factor in S. epidermidis and their impact on neonatal infections.},
}
@article {pmid30884970,
year = {2019},
author = {Sadiq, FA and Flint, S and Sakandar, HA and He, G},
title = {Molecular regulation of adhesion and biofilm formation in high and low biofilm producers of Bacillus licheniformis using RNA-Seq.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-16},
doi = {10.1080/08927014.2019.1575960},
pmid = {30884970},
issn = {1029-2454},
abstract = {RNA sequencing was used to reveal transcriptional changes during the motile-to-sessile switch in high and low biofilm-forming dairy strains of B. licheniformis isolated from Chinese milk powders. A significant part of the whole gene content was affected during this transition in both strains. In terms of the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, seven metabolic pathways were significantly downregulated in the planktonic state compared to the biofilm state in both strains. Lipid and sugar metabolism seemed to play an important role in matrix production. Several genes involved in adhesion, matrix production and the matrix coating were either absent or less expressed in the biofilm state of the low biofilm producer compared to the high biofilm producer. Genes related to sporulation and the production of extracellular polymeric substances were concomitantly expressed in the biofilm state of both strains. These comprehensive insights will be helpful for future research into mechanisms and targets.},
}
@article {pmid30884874,
year = {2019},
author = {Trotsko, N and Kosikowska, U and Andrzejczuk, S and Paneth, A and Wujec, M},
title = {Influence of Thiazolidine-2,4-Dione Derivatives with Azolidine or Thiosemicarbazone Moieties on Haemophilus spp. Planktonic or Biofilm-Forming Cells.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {6},
pages = {},
doi = {10.3390/molecules24061051},
pmid = {30884874},
issn = {1420-3049},
abstract = {Biofilm, naturally formed by microorganisms as integrated surface-bound communities, is one of the reasons for the development of antimicrobial resistance. Haemophilus spp. are common and representative opportunistic Gram-negative rods forming from the upper respiratory tract microbiota. The aim of this paper was to evaluate the influence of thiazolidine-2,4-dionebased azolidine and chlorophenylthiosemicarbazone hybrids against both planktonic and biofilm-forming Haemophilus spp. cells. The in vitro activity against planktonic and biofilm-forming cells of the tested compounds were evaluated by using the broth microdilution method. These activities were detected against reference and clinical strains of Haemophilus spp. on the basis of MICs (minimal inhibitory concentrations) and MBICs (minimal biofilm inhibitory concentrations). In addition, anti-adhesive properties of these compounds were examined. The target compounds showed potential activity against planktonic cells with MIC = 62.5⁻500 mg/L and biofilm-forming cells with MBIC = 62.5⁻1000 mg/L. The observed anti-adhesive properties of the tested compounds were reversible during long-term incubation in a lower concentration of compounds.},
}
@article {pmid30884686,
year = {2019},
author = {Merino, L and Procura, F and Trejo, FM and Bueno, DJ and Golowczyc, MA},
title = {Biofilm formation by Salmonella sp. in the poultry industry: Detection, control and eradication strategies.},
journal = {Food research international (Ottawa, Ont.)},
volume = {119},
number = {},
pages = {530-540},
doi = {10.1016/j.foodres.2017.11.024},
pmid = {30884686},
issn = {1873-7145},
abstract = {Salmonella represents an important global public health problem and it is an emerging zoonotic bacterial threat in the poultry industry. Diverse registered human cases of salmonellosis shown poultry origins. Various control measures have been employed both at the farming and processing levels to address it. This review focuses on traditional and new detection techniques of biofilm formation by Salmonella spp. and different approaches that can be used to prevent and/or control biofilm formation by these bacteria. A number of methodologies based on different approximations have been recently employed to detect and evaluate bacteria attached to surfaces, including real-time polymerase chain reaction (PCR), confocal laser scanning microscopy and Optical Coherence Tomography. Due to persistence of Salmonella biofilm in food processing environments after cleaning and sanitation, control and eradication strategies in poultry industry should be constantly studied. In this sense, the use of several alternatives to control Salmonella biofilm formation, such as lactic acid bacteria, phagetherapy, extracts from aromatic plants, quorum sensing inhibitors, bacteriocins and nanomaterials, have been successfully tested and will be reviewed.},
}
@article {pmid30884454,
year = {2019},
author = {Del Rio, M and de la Canal, L and Pinedo, M and Mora-Montes, HM and Regente, M},
title = {Effects of the binding of a Helianthus annuus lectin to Candida albicans cell wall on biofilm development and adhesion to host cells.},
journal = {Phytomedicine : international journal of phytotherapy and phytopharmacology},
volume = {58},
number = {},
pages = {152875},
doi = {10.1016/j.phymed.2019.152875},
pmid = {30884454},
issn = {1618-095X},
abstract = {BACKGROUND: In our previous study, we isolated and characterized a lectin called Helja from Helianthus annuus (sunflower) and then, in a further study, demonstrated its antifungal activity against Candida spp. Since Candida infections are a major health concern due to the increasing emergence of antifungal resistant strains, the search for new antifungal agents offers a promising opportunity for improving the treatment strategies against candidiasis.<br><br>PURPOSE: The aim of this work was to get insights about the mechanism of action of Helja, an antifungal lectin of H. annuus, and to explore its ability to inhibit Candida albicans biofilm development and adherence to buccal epithelial cells (BEC).<br><br>STUDY DESIGN/METHODS: Yeast viability was evaluated by Evans Blue uptake and counting of colony forming units (CFU). The yeast cell integrity was assessed using Calcofluor White (CFW) as a cell wall perturbing agent and sorbitol as osmotic protectant. The induction of oxidative stress was evaluated using 3,3'-diaminobenzidine (DAB) for detection of hydrogen peroxide. The adherence was determined by counting the yeast cells attached to BEC after methylene blue staining. The biofilms were developed on polystyrene microplates, visualized by confocal laser scanning microscopy and the viable biomass was quantified by CFU counting. The binding lectin-Candida was assessed using Helja conjugated to fluorescein isothiocyanate (Helja-FITC) and simultaneous staining with CFW. The cellular surface hydrophobicity (CSH) was determined using a microbial adhesion to hydrocarbons method.<br><br>RESULTS: C. albicans cells treated with 0.1 µg/µl of Helja showed a drastic decrease in yeast survival. The lectin affected the fungal cell integrity, induced the production of hydrogen peroxide and inhibited the morphological transition from yeast to filamentous forms. Helja caused a significant reduction of adherent cells and a decrease in biofilm biomass and coverage area. The treatment with the protein also reduced the surface hydrophobicity of fungal cells. We show the binding of Helja-FITC to yeast cells distributed as a thin outer layer to the CFW signal, and this interaction was displaced by mannose and Concanavalin A.<br><br>CONCLUSION: The results demonstrate the interaction of Helja with the mannoproteins of C. albicans cell wall, the disruption of the cell integrity, the induction of oxidative stress, the inhibition of the morphological transition from yeast to filamentous forms and the fungal cell viability loss. The binding Helja-Candida also provides a possible explanation of the lectin effect on cell adherence, biofilm development and CSH, relevant features related to virulence of the pathogen.},
}
@article {pmid30884254,
year = {2019},
author = {Tang, R and Zhu, J and Feng, L and Li, J and Liu, X},
title = {Characterization of LuxI/LuxR and their regulation involved in biofilm formation and stress resistance in fish spoilers Pseudomonas fluorescens.},
journal = {International journal of food microbiology},
volume = {297},
number = {},
pages = {60-71},
doi = {10.1016/j.ijfoodmicro.2018.12.011},
pmid = {30884254},
issn = {1879-3460},
abstract = {Quorum sensing (QS) is crucial for adaption and development of foodborne bacteria in diverse environments. Pseudomonas fluorescens PF07 with QS mediated acylated homoserine lactones (AHLs) activity was isolated from spoiled large yellow croaker (Pseudosciaena crocea). In this study AHL-mediated QS system was characterized and their roles in biofilm formation, motility, stress response and spoilage of P. fluorescens were evaluated. A LuxI/LuxR homolog consisting of a conserved AHL synthase gene (luxI) and a transcriptional regulator gene (luxR) was identified in the strain. Two in-frame deletion mutants of luxI and luxR, ∆luxI and ∆luxR, were constructed to explore their QS signaling function in P. fluorescens. Three types of AHLs were detected in PF07 culture by LC-MS/MS, and N-butanoyl-l-homoserine lactone (C4-HSL) was a major signal molecule. The C4-HSL activities was almost abolished in ∆luxI, and decreased greatly in ∆luxR. Compared with wild type (WT) strain, both ∆luxI and ∆luxR showed the significant decrease of biofilm biomass and expolysaccharide production, resulting in thinner and incompact biofilm structure, but promoted swimming motility. The resistance of P. fluorescens to H2O2, heat, NaCl and crystal violet apparently declined in two mutants compared to WT. Spoilage factors, siderophore and protease, apparently attenuated due to deletion of luxI or luxR gene, while the growth and TVB-N production did not differ. Furthermore, the changes of the biofilm formation, motility and protease in ∆luxI strain were partially restored by the exogenous C4-HSL. In agreement with the effect of two mutants on various phenotypes, the transcriptions of alg, lapA, flgA, rpoS, and aprX were significantly down-regulated, and flgA was up-regulated in ∆luxI and ∆luxR. Therefore, the present study highlighted that the co-operation of LuxI/LuxR homolog was an important QS regulator in biofilm formation, motility and spoilage potential, and hinted its positive regulation of stress resistance with RpoS in P. fluorescens.},
}
@article {pmid30883044,
year = {2019},
author = {Percival, SL and Mayer, D and Kirsner, RS and Schultz, G and Weir, D and Roy, S and Alavi, A and Romanelli, M},
title = {Surfactants: Role in biofilm management and cellular behaviour.},
journal = {International wound journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/iwj.13093},
pmid = {30883044},
issn = {1742-481X},
support = {//Medline Industries Inc/ ; },
abstract = {Appropriate and effective wound cleaning represents an important process that is necessary for preparing the wound for improved wound healing and for helping to dislodge biofilms. Wound cleaning is of paramount importance to wound bed preparation for helping to enhance wound healing. Surfactant applications in wound care may represent an important area in the cleaning continuum. However, understanding of the role and significance of surfactants in wound cleansing, biofilm prevention and control, and enhancing cellular viability and proliferation is currently lacking. Despite this, some recent evidence on poloxamer-based surfactants where the surfactants are present in high concentration have been shown to have an important role to play in biofilm management; matrix metalloproteinase modulation; reducing inflammation; and enhancing cellular proliferation, behaviour, and viability. Consequently, this review aims to discuss the role, mode of action, and clinical significance of the use of medically accepted surfactants, with a focus on concentrated poloxamer-based surfactants, to wound healing but, more specifically, the role they may play in biofilm management and effects on cellular repair.},
}
@article {pmid30883023,
year = {2019},
author = {Junka, A and Bartoszewicz, M and Dziadas, M and Szymczyk, P and Dydak, K and Żywicka, A and Owczarek, A and Bil-Lula, I and Czajkowska, J and Fijałkowski, K},
title = {Application of bacterial cellulose experimental dressings saturated with gentamycin for management of bone biofilm in vitro and ex vivo.},
journal = {Journal of biomedical materials research. Part B, Applied biomaterials},
volume = {},
number = {},
pages = {},
doi = {10.1002/jbm.b.34362},
pmid = {30883023},
issn = {1552-4981},
support = {ST-904//Statutory UMED/ ; },
abstract = {Bacterial cellulose is one of the most promising polymers of recent years. Herein, we present a possibility of BC application as a carrier of gentamycin antibiotic for the treatment and prevention of bone infections. We have shown that BC saturated with gentamycin significantly reduces the level of biofilm-forming bone pathogens, namely Staphylococcus aureus and Pseudomonas aeruginosa, and displays very low cytotoxicity in vitro against osteoblast cell cultures. Another beneficial feature of our prototype dressing is prolonged release of gentamycin, which provides efficient protection from microbial contamination and subsequent infection. Moreover, it seems that bacterial cellulose (BC) alone without any antimicrobial added, may serve as a barrier by significantly hampering the ability of the pathogen to penetrate to the bone structure. Therefore, a gentamycin-saturated BC dressing may be considered as a possible alternative for gentamycin collagen sponge broadly used in clinical setting. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B, 2019.},
}
@article {pmid30882296,
year = {2019},
author = {Luo, TL and Hayashi, M and Zsiska, M and Circello, B and Eisenberg, M and Gonzalez-Cabezas, C and Foxman, B and Marrs, CF and Rickard, AH},
title = {Introducing BAIT (Biofilm Architecture Inference Tool): a software program to evaluate the architecture of oral multi-species biofilms.},
journal = {Microbiology (Reading, England)},
volume = {},
number = {},
pages = {},
doi = {10.1099/mic.0.000761},
pmid = {30882296},
issn = {1465-2080},
abstract = {Biofilm model systems are used to study biofilm growth and predict the effects of anti-biofilm interventions within the human oral cavity. Many in vitro biofilm model systems use a confocal laser scanning microscope (CLSM) in conjunction with image analysis tools to study biofilms. The aim of this study was to evaluate an in-house developed image analysis software program that we call BAIT (Biofilm Architecture Inference Tool) to quantify the architecture of oral multi-species biofilms following anti-biofilm interventions using a microfluidic biofilm system. Differences in architecture were compared between untreated biofilms and those treated with water (negative control), sodium gluconate ('placebo') or stannous fluoride (SnF2). The microfluidic system was inoculated with pooled human saliva and biofilms were developed over 22 h in filter-sterilized 25 % pooled human saliva. During this period, biofilms were treated with water, sodium gluconate, or SnF2 (1000, 3439 or 10 000 p.p.m. Sn2+) 8 and 18 h post-inoculation. After 22 h of growth, biofilms were stained with LIVE/DEAD stain, and imaged by CLSM. BAIT was used to calculate biofilm biovolume, total number of objects, surface area, fluffiness, connectivity, convex hull porosity and viability. Image analysis showed oral biofilm architecture was significantly altered by 3439 and 10 000 p.p.m. Sn2+ treatment regimens, resulting in decreased biovolume, surface area, number of objects and connectivity, while fluffiness increased (P<0.01). In conclusion, BAIT was shown to be able to measure the changes in biofilm architecture and detects possible antimicrobial and anti-biofilm effects of candidate agents.},
}
@article {pmid30881988,
year = {2019},
author = {Pate, M and Mičunovič, J and Golob, M and Vestby, LK and Ocepek, M},
title = {Salmonella Infantis in Broiler Flocks in Slovenia: The Prevalence of Multidrug Resistant Strains with High Genetic Homogeneity and Low Biofilm-Forming Ability.},
journal = {BioMed research international},
volume = {2019},
number = {},
pages = {4981463},
doi = {10.1155/2019/4981463},
pmid = {30881988},
issn = {2314-6141},
abstract = {For almost a decade, the number of Salmonella enterica subspecies enterica serovar Infantis-positive broiler flocks has been steadily increasing in Slovenia, doubling the number of positive holdings in only a few years. Since multidrug resistant S. Infantis isolates are highly prevalent in the broiler meat industry and may represent a public health concern through the food chain, we aimed to investigate the antimicrobial susceptibility, genetic diversity, and biofilm-forming ability of S. Infantis from Slovenian broiler flocks. A total of 87 S. Infantis strains isolated from broiler faeces in the period between 2007 and 2013 were studied. The samples originated from 41 farms which were subcontractors of three major food business operators and from two autonomously operating holdings (farms). Isolates were phenotypically tested for their susceptibility to 14 antimicrobials from nine classes by determining the minimum inhibitory concentration with the microdilution method. Only 8% of the isolates were susceptible to all of the antimicrobial agents tested, while 88.5% of the isolates were multidrug resistant, with the most common resistance pattern CipNxSSuT (65.5%) followed by CipNxSuT (17.2%). Pulsed-field gel electrophoresis (PFGE) divided the strains into five clusters (A-E) comprising 16 distinct XbaI PFGE profiles. Sixty-five out of 87 isolates were grouped in clusters A and B, with the predominant PFGE profiles A1 and B1 encompassing 33 and 28 isolates, respectively. A vast majority of the isolates (75/87) showed >90% PFGE profile similarity. The biofilm-forming capacity of the tested isolates, determined with crystal violet assay in polystyrene microwell plates, was generally weak. The average biofilm formation for persistent strains was higher than for presumably nonpersistent strains; however, the difference was not significant. It seems that S. Infantis persistence on broiler farms is more related to its widespread occurrence in the broiler production chain and ineffective disinfection protocols than to its ability to form biofilm.},
}
@article {pmid30881614,
year = {2019},
author = {Patil, PC and Tan, J and Demuth, DR and Luzzio, FA},
title = {'Second-generation' 1,2,3-triazole-based inhibitors of Porphyromonas gingivalis adherence to oral streptococci and biofilm formation.},
journal = {MedChemComm},
volume = {10},
number = {2},
pages = {268-279},
doi = {10.1039/c8md00405f},
pmid = {30881614},
issn = {2040-2511},
support = {R01 DE023206/DE/NIDCR NIH HHS/United States ; },
abstract = {Several 'second-generation' click inhibitors of the multi-species biofilm propagated by the adherence of the oral pathogen Porphyromonas gingivalis to Streptococcus gordonii were synthesized and evaluated. The design of the structures was based on the results obtained with the first-generation diphenyloxazole 'click' inhibitors which bear suitable hydrophobic and polar groups within a dual scaffold molecule bearing a 1,2,3-triazole spacer. The structures of the synthetic targets reported herein now consist of a triazolyl(phenylsulfonylmethyl) and a triazolyl(phenylsulfinylmethyl) spacer which joins a 4,5-diphenyloxazole with both phenyl rings bearing lipophilic substituents. The triazolyl &quot;linker&quot; group is formed by a click reaction between the 4-azido(phenylsulfonyl/sulfinylmethyl) oxazoles and acetylenic components having aryl groups bearing hydrophobic substituents. The 1,3,5-trisubstituted-2,4,6-triazine scaffold of the most active click compounds were modeled after the structural motif termed the VXXLL nuclear receptor (NR) box. When substituted at the 3- and 5-positions with 2- and 4-fluorophenylamino and N,N-diethylamino units, the candidates bearing the 1,3,5-trisubstituted-2,4,6-triazine scaffold formed a substantial subset of the second-generation click candidates. Four of the click products, compounds 95, 111, 115 and 122 showed inhibition of the adherence of P. gingivalis to S. gordonii with an IC50 range of 2.3-4.3 μM and only 111 exhibited cytotoxic activity against telomerase immortalized gingival keratinocytes at 60 μM. These results suggest that compounds 95, 115, 122, and possibly 111 represent the most suitable compounds to evaluate for activity in vivo.},
}
@article {pmid30881456,
year = {2019},
author = {Awoke, N and Kassa, T and Teshager, L},
title = {Magnitude of Biofilm Formation and Antimicrobial Resistance Pattern of Bacteria Isolated from Urinary Catheterized Inpatients of Jimma University Medical Center, Southwest Ethiopia.},
journal = {International journal of microbiology},
volume = {2019},
number = {},
pages = {5729568},
doi = {10.1155/2019/5729568},
pmid = {30881456},
issn = {1687-918X},
abstract = {Biofilm formation is one of the features of most bacteria. Catheterization in medicine is a source of highly resistant bacterial infections, and those bacteria respond poorly to antimicrobial therapy. Bacterial biofilm features were not described from catheterized inpatients in Ethiopia as its formation is known to afford antimicrobial resistance and challenge patient management. The aim of this study was to isolate catheter-associated urinary bacterial pathogens, their biofilm formation, and antimicrobial susceptibility pattern among inpatients of Jimma University Medical Center (JUMC) in Southwest Ethiopia. A prospective cross-sectional study was conducted among urinary catheterized inpatients of JUMC from February to August 2016. A total of 143 study participants were enrolled consecutively in this study. Urine samples were collected from catheterized patients and processed using a standard bacteriological protocol for isolation and identification. Evaluation of in vitro biofilm formation and antimicrobial susceptibility pattern of uropathogenic bacteria was done using microtiter plates and disk diffusion method, respectively. Data were cleaned, coded, and entered into SPSS version 20 for analysis. All statistical test values of p < 0.05 were considered statistically significant. From all study participants, mean age was 44 years. Sixty bacterial strains were recovered from 57 urinary catheterized inpatients among which 54 of them were monomicrobial (94.7%). The remaining six bacterial strains were recovered from three study participants each with two bacterial isolates. The predominant bacterial isolates were Gram-negative bacteria with E. coli turning out first. About 80% of bacterial isolates were biofilm formers. The majority of the bacteria were resistant to commonly prescribed antimicrobial agents. In conclusion, the majority of bacterial uropathogen isolates were Gram-negative, biofilm formers, and resistant to commonly prescribed antimicrobial agents. Relatively ciprofloxacin, nitrofurantoin, and amikacin were highly effective against most isolated bacteria.},
}
@article {pmid30880981,
year = {2019},
author = {Fu, YY and Zhang, L and Yang, Y and Liu, CW and He, YN and Li, P and Yu, X},
title = {Synergistic antibacterial effect of ultrasound microbubbles combined with chitosan-modified polymyxin B-loaded liposomes on biofilm-producing Acinetobacter baumannii.},
journal = {International journal of nanomedicine},
volume = {14},
number = {},
pages = {1805-1815},
doi = {10.2147/IJN.S186571},
pmid = {30880981},
issn = {1178-2013},
abstract = {Purpose: Resistant strains of Acinetobacter baumannii (AB) that can form biofilms are resistant to polymyxin. Therefore, effective and safe polymyxin preparations against biofilm-producing AB are urgently needed. This study aims to prepare chitosan-modified polymyxin B-loaded liposomes (CLPs) and ultrasound microbubbles (USMBs) and then explore the synergistic antibacterial effects of USMBs combined with CLPs in vitro.<br><br>Methods: CLPs were prepared using a modified injection method, and microbubbles were prepared using a simple mechanical vibration method. Minimal biofilm inhibitory concentration (MBIC) of CLPs against resistant biofilm-producing AB was determined. Antibacterial activities of CLPs with or without USMBs were analyzed by crystal violet staining and resazurin assays to evaluate biofilm mass and viable counts, respectively. Then, the anti-biofilm effects of CLPs with or without USMBs on biofilm-producing AB were confirmed via scanning electron microscopy (SEM) analysis.<br><br>Results: We prepared CLPs that were 225.17±17.85 nm in size and carried positive charges of 12.64±1.44 mV. These CLPs, with higher encapsulation efficiency and drug loading, could exhibit a sustained release effect. We prepared microbubbles that were 2.391±0.052 µm in size and carried negative charges of -4.32±0.43 mV. The MBICs of the CLPs on the biofilm-producing AB was 8±2 µg/mL, while that of polymyxin B was 32±2 µg/mL. USMBs in combination with 2 µg/mL of polymyxin B could completely eliminate the biofilm-producing AB and achieve the maximum antimicrobial effects (P>0.05 vs sterile blank control). SEM imaging revealed some scattered bacteria without a biofilm structure in the USMB combined with the CLP group, confirming that this combination has the greatest anti-biofilm effects.<br><br>Conclusion: In this research, we successfully prepared USMBs and CLPs that have a more significant antibacterial effect on biofilm-forming AB than polymyxin B alone. Experiments in vitro indicate that the synergistic antibacterial effect of combining USMBs with CLPs containing as little as 2 µg/mL of polymyxin B is sufficient to almost eliminate drug-resistant biofilm-producing AB.},
}
@article {pmid30877884,
year = {2019},
author = {Roeslan, MO and Ayudhya, TDN and Yingyongnarongkul, BE and Koontongkaew, S},
title = {Anti-biofilm, nitric oxide inhibition and wound healing potential of purpurin-18 phytyl ester isolated from Clinacanthus nutans leaves.},
journal = {Biomedicine &amp; pharmacotherapy = Biomedecine &amp; pharmacotherapie},
volume = {113},
number = {},
pages = {108724},
doi = {10.1016/j.biopha.2019.108724},
pmid = {30877884},
issn = {1950-6007},
abstract = {AIMS: Clinacanthus nutans (C. nutans) has demonstrated anti-inflammatory activity, however, the active compound generating this activity remains unknown. The aim of this study was to identify the bioactive compound in C. nutans responsible for its anti-inflammatory, in-vitro wound healing, and anti-biofilm activities.<br><br>MAIN METHODS: A pure compound was isolated from the chloroform extract (CE) of C. nutans leaves by chromatographic techniques and bioassay-guided fractionation. This compound's structure was determined by spectroscopic analyses (FTIR/NMR/HRES-MS). Biological activities were evaluated using cytotoxicity, nitric oxide (NO), wound scratch, anti-microbial activity, and anti-biofilm assays; and the compound's bactericidal depth into the biofilm was visualized by confocal laser scanning microscopy.<br><br>KEY FINDINGS: CE and its pure isolated compound, purpurin-18 phytyl ester (P18PE), significantly inhibited lipopolysaccharide (LPS)-induced NO production in RAW 264.7 cells at concentrations of 100 μg/ml and 10-100 μg/ml, respectively. These concentrations significantly induced wound closure by human gingival fibroblasts. CE (100-1000μg/ml) and P18PE (1-500 μg/ml) did not inhibit Streptococcus (S.) mutans growth. However, these concentrations significantly reduced S. mutans biofilm formation below 50% at 250 μg/ml for CE, and 25 μg/ml for P18PE (p<0.05).<br><br>SIGNIFICANCE: C. nutans contains a bioactive compound, P18PE, which exhibits anti-inflammatory, in-vitro wound healing, and anti-biofilm activities.},
}
@article {pmid30876404,
year = {2019},
author = {Khider, M and Hjerde, E and Hansen, H and Willassen, NP},
title = {Differential expression profiling of ΔlitR and ΔrpoQ mutants reveals insight into QS regulation of motility, adhesion and biofilm formation in Aliivibrio salmonicida.},
journal = {BMC genomics},
volume = {20},
number = {1},
pages = {220},
doi = {10.1186/s12864-019-5594-4},
pmid = {30876404},
issn = {1471-2164},
support = {IN-1096130//UiT-Publiseringsfondet/ ; },
abstract = {BACKGROUND: The coordination of group behaviors in bacteria is achieved by a cell-cell signaling process called quorum sensing (QS). QS is an intercellular communication system, which synchronously controls expression of a vast range of genes in response to changes in cell density and is mediated by autoinducers that act as extracellular signals. Aliivibrio salmonicida, the causative agent of cold-water vibrosis in marine aquacultures, uses QS to regulate several activities such as motility, biofilm formation, adhesion and rugose colony morphology. However, little is known about either genes or detailed mechanisms involved in the regulation of these phenotypes.<br><br>RESULTS: Differential expression profiling allowed us to define the genes involved in controlling phenotypes related to QS in A. salmonicida LFI1238. RNA sequencing data revealed that the number of expressed genes in A. salmonicida, ΔlitR and ΔrpoQ mutants were significantly altered due to changes in cell density. These included genes that were distributed among the 21 functional groups, mainly presented in cell envelope, cell processes, extrachromosomal/foreign DNA and transport-binding proteins functional groups. The comparative transcriptome of A. salmonicida wild-type at high cell density relative to low cell density revealed 1013 genes to be either up- or downregulated. Thirty-six downregulated genes were gene clusters encoding biosynthesis of the flagellar and chemotaxis genes. Additionally we identified significant expression for genes involved in acyl homoserine lactone (AHL) synthesis, adhesion and early colonization. The transcriptome profile of ΔrpoQ compared to the wild-type revealed 384 differensially expressed genes (DEGs) that allowed us to assign genes involved in regulating motility, adhesion and colony rugosity. Indicating the importance of RpoQ in controlling several QS related activities. Furthermore, the comparison of the transcriptome profiles of ΔlitR and ΔrpoQ mutants, exposed numerous overlapping DEGs that were essential for motility, exopolysaccharide production via syp operon and genes associated with tad operon.<br><br>CONCLUSION: Our findings indicate previously unexplained functional roles for LitR and RpoQ in regulation of different phenotypes related to QS. Our transcriptome data provide a better understanding of the regulation cascade of motility, wrinkling colony morphology and biofilm formation and will offer a major source for further research and analysis on this important field.},
}
@article {pmid30874983,
year = {2019},
author = {Liu, N and Skauge, T and Landa-Marbán, D and Hovland, B and Thorbjørnsen, B and Radu, FA and Vik, BF and Baumann, T and Bødtker, G},
title = {Microfluidic study of effects of flow velocity and nutrient concentration on biofilm accumulation and adhesive strength in the flowing and no-flowing microchannels.},
journal = {Journal of industrial microbiology &amp; biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10295-019-02161-x},
pmid = {30874983},
issn = {1476-5535},
support = {255426//Research Council of Norway/ ; },
abstract = {Biofilm accumulation in porous media can cause pore plugging and change many of the physical properties of porous media. Engineering bioplugging may have significant applications for many industrial processes, while improved knowledge on biofilm accumulation in porous media at porescale in general has broad relevance for a range of industries as well as environmental and water research. The experimental results by means of microscopic imaging over a T-shape microchannel clearly show that increase in fluid velocity could facilitate biofilm growth, but that above a velocity threshold, biofilm detachment and inhibition of biofilm formation due to high shear stress were observed. High nutrient concentration prompts the biofilm growth; however, the generated biofilm displays a weak adhesive strength. This paper provides an overview of biofilm development in a hydrodynamic environment for better prediction and modelling of bioplugging processes associated with porous systems in petroleum industry, hydrogeology and water purification.},
}
@article {pmid30874395,
year = {2019},
author = {Yang, J and Qiu, L and Huang, Y and Chen, Y and Rao, S and Ruan, W and Zhao, G and Ye, L},
title = {[The inhibition of accessory gene regulator C specific binding peptides on biofilm formation of Staphylococcus epidermidis on the surface of polyvinyl chloride in vitro].},
journal = {Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery},
volume = {33},
number = {3},
pages = {349-355},
doi = {10.7507/1002-1892.201806110},
pmid = {30874395},
issn = {1002-1892},
abstract = {Objective: To investigate the effect of accessory gene regulator C (agr C) specific binding peptides (named N1) on the biofilm formation of Staphylococcus epidermidis on the surface of polyvinyl chloride (PVC) materials in vitro.<br><br>Methods: Firstly, the two strains (ATCC35984, ATCC12228) were cultured with N1 at concentrations of 100, 200, 400, 800, and 1 600 μg/mL, respectively. The control group was cultured with agrC specific binding unrelated peptides (named N0) at the same concentrations and the absorbance (A) value was measured after 24 hours to determine the optimal bacteriostatic concentration of N1. The two strains were cultured with N1 and N0 of the optimal concentration, respectively. The A values were measured at 6, 12, 18, 24, 30, and 48 hours to observe the effect of N1 on the biofilm formation ability of Staphylococcus epidermidis. On this basis, the surface structure of the biofilm on the surface of PVC material was observed by scanning electron microscopy after 6, 12, 18, 24, and 30 hours of incubation with PVC material sheet. The thickness of the biofilm was observed by laser confocal microscopy after 6, 12, 18, and 24 hours of incubation with ATCC35984 strain.<br><br>Results: The optimal bacteriostatic concentration of N1 was 800 μg/mL. ATCC 12228 strain did not form obvious biofilm after being cultured with N1 and N0. When ATCC35984 strain was cultured with N1 and N0 for 12 hours, the difference in biofilm formation ability between groups N1 and N0 was statistically significant (P<0.05), but there was no significant difference at 6, 18, 24, 30, and 48 hours (P>0.05). Scanning electron microscopy examination showed that mature biofilm structure was observed in ATCC35984 strain and was not observed in ATCC12228 strain. Laser confocal microscopy observation showed that the number of bacteria in the group N1 was significantly lower than that in the group N0 at 12 hours, and the most of bacteria were dead bacteria. There was no significant difference in the number of bacteria at 6, 18, and 24 hours, and the most of them were live bacteria. The biofilm thickness of group N1 was significantly lower than that of group N0 at 12 and 18 hours (P<0.05).<br><br>Conclusion: The intensity of N1 inhibiting the formation of Staphylococcus epidermidis biofilm is dose-dependent. During the aggregation period, N1 can inhibit the biofilm formation by hindering the bacterial growth and aggregation. The inhibition effect on mature biofilm is not obvious.},
}
@article {pmid30873665,
year = {2019},
author = {Lerch, MF and Schoenfelder, SMK and Marincola, G and Wencker, FDR and Eckart, M and Förstner, KU and Sharma, CM and Thormann, KM and Kucklick, M and Engelmann, S and Ziebuhr, W},
title = {A non-coding RNA from the intercellular adhesion (ica) locus of Staphylococcus epidermidis controls polysaccharide intercellular adhesion (PIA)-mediated biofilm formation.},
journal = {Molecular microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/mmi.14238},
pmid = {30873665},
issn = {1365-2958},
support = {01KI1014E//German Federal Ministry of Education and Research (BMBF)/ ; GZ:INST 188/365-1 FUGG//DFG programme 'Forschungsgroßgeräte'/ ; SPP1617 (ZI 665/2)//DFG programme 'Forschungsgroßgeräte'/ ; TCRC 34 INST 292/67; B04//DFG programme 'Forschungsgroßgeräte'/ ; ZI 665/3-1//DFG programme 'Forschungsgroßgeräte'/ ; },
abstract = {Polysaccharide intercellular adhesin (PIA)-associated biofilm formation is mediated by the intercellular adhesin (ica) locus and represents a major pathomechanism of Staphylococcus epidermidis. Here, we report on a novel long non-coding (nc)RNA, named IcaZ, which is approximately 400 nucleotides in size. icaZ is located downstream of the ica repressor gene icaR and partially overlaps with the icaR 3' UTR. icaZ exclusively exists in ica-positive S. epidermidis, but not in S. aureus or other staphylococci. Inactivation of the gene completely abolishes PIA production. IcaZ is transcribed as a primary transcript from its own promoter during early- and mid-exponential growth and its transcription is induced by low temperature, ethanol and salt stress. IcaZ targets the icaR 5' UTR and hampers icaR mRNA translation, which alleviates repression of icaADBC operon transcription and results in PIA production. Interestingly, other than in S. aureus, posttranscriptional control of icaR mRNA in S. epidermidis does not involve icaR mRNA 5'/3' UTR base pairing. This suggests major structural and functional differences in icaADBC operon regulation between the two species that also involve the recruitment of ncRNAs. Together, the IcaZ ncRNA represents an unprecedented novel species-specific player involved in the control of PIA production in NBSP S. epidermidis.},
}
@article {pmid30873271,
year = {2018},
author = {Hosseini, SS and Ghaemi, E and Koohsar, F},
title = {Influence of ZnO nanoparticles on Candida albicans isolates biofilm formed on the urinary catheter.},
journal = {Iranian journal of microbiology},
volume = {10},
number = {6},
pages = {424-432},
pmid = {30873271},
issn = {2008-3289},
abstract = {Background and Objectives: The aim of this study was to determine the effect of zinc oxide nanoparticle (ZnO-np) solution in the surface catheter on C. albicans adhesion and biofilm formation.<br><br>Materials and Methods: Out of 260 isolates from urinary catheter, 133 were determined as C. albicans by common phenotypic and genotyping methods. ZnO nanoparticles with 30 nm were made by the sol-gel method, which was confirmed by XRD (X-ray diffraction) and scanning electron microscope (SEM) methods. Candidal adhesion and biofilm assays were performed on catheter surfaces for 2 and 48 hours, respectively. The effect of sub-MIC (minimum inhibitory concentrations) and MIC concentrations of ZnO-np on biofilm formation was evaluated after 24 hours using Crystal violet (CV), colony-forming unit (CFU), and SEM.<br><br>Results: Out of 133 C. albicans isolates, 20 (15%) fluconazole-resistant and 113 (85%) susceptible isolates were determined by the disk diffusion method. Results showed that both isolates adhered to biofilm formation on the catheter surfaces. A significantly (P< 0.05) higher number of CFUs was evident in fluconazole-resistant biofilms compared to those formed by susceptible isolates. ZnO-np reduced biofilm biomass and CFUs of dual isolate biofilms (P< 0.05). ZnO nanoparticles had a significantly (P< 0.05) greater effect on reducing fluconazole-resistant C. albicans biofilm biomass compared to susceptible isolates.<br><br>Conclusion: Zno-np exhibits inhibitory effects on biofilms of both isolates. These findings provide an important advantage of ZnO that may be useful in the treatment of catheter-related urinary tract infection.},
}
@article {pmid30873270,
year = {2018},
author = {Baghini, GS and Sepahi, AA and Tabatabaei, RR and Tahvildari, K},
title = {The combined effects of ethanolic extract of Artemisia aucheri and Artemisia oliveriana on biofilm genes expression of methicillin resistant Staphylococcus aureus.},
journal = {Iranian journal of microbiology},
volume = {10},
number = {6},
pages = {417-423},
pmid = {30873270},
issn = {2008-3289},
abstract = {Background and Objectives: One of the most important antibiotic-resistant bacteria is methicillin-resistant Staphylococcus aureus (MRSA) biofilm that has caused significant problems in treating the patients. Therefore, the aim of this study was to evaluate the levels of expression of genes involved in biofilm formation in MRSA (ATCC 33591) while being treated by a combination of Artemisia aucheri and Artemisia oliveriana.<br><br>Materials and Methods: The minimum inhibitory concentration (MIC) of ethanolic extract of A. aucheri and A. oliveriana and also the minimum inhibitory concentration of combination of both extracts were 512, 1024 and 256 μg/ml, respectively; then at concentrations lower than the MIC, expression levels of the desired genes were determined by Real Time PCR.<br><br>Results: Based on results, using a combination of two ethanolic extracts had a significant effect on expression of genes involved in biofilm formation in MRSA. The expression level of icaA at 4, 8, 16 h after being treated by herbal extracts of A. aucheri and A. oliveriana was 0.293, 0.121, 0.044, respectively. The expression level of icaD was 0.285, 0.097, 0.088, respectively, while that of ebps was 0.087, 0.042, 0.009 at 4, 8 and 16 h, respectively.<br><br>Conclusion: This study provided evidence that ethanol extract of A. oliveriava and A. aucheri can inhibit the biofilm formation of S. aureus. As a traditional Iranian medicine, A. oliveriava and A. aucheri extracts have a potential antibiofilm formation against MRSA strains.},
}
@article {pmid30873149,
year = {2019},
author = {Calderón, CE and Tienda, S and Heredia-Ponce, Z and Arrebola, E and Cárcamo-Oyarce, G and Eberl, L and Cazorla, FM},
title = {The Compound 2-Hexyl, 5-Propyl Resorcinol Has a Key Role in Biofilm Formation by the Biocontrol Rhizobacterium Pseudomonas chlororaphis PCL1606.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {396},
doi = {10.3389/fmicb.2019.00396},
pmid = {30873149},
issn = {1664-302X},
abstract = {The production of the compound 2-hexyl-5-propyl resorcinol (HPR) by the biocontrol rhizobacterium Pseudomonas chlororaphis PCL1606 (PcPCL1606) is crucial for fungal antagonism and biocontrol activity that protects plants against the phytopathogenic fungus Rosellinia necatrix. The production of HPR is also involved in avocado root colonization during the biocontrol process. This pleiotrophic response prompted us to study the potential role of HPR production in biofilm formation. The swimming motility of PcPLL1606 is enhanced by the disruption of HPR production. Mutants impaired in HPR production, revealed that adhesion, colony morphology, and typical air-liquid interphase pellicles were all dependent on HPR production. The role of HPR production in biofilm architecture was also analyzed in flow chamber experiments. These experiments revealed that the HPR mutant cells had less tight unions than those producing HPR, suggesting an involvement of HPR in the production of the biofilm matrix.},
}
@article {pmid30872708,
year = {2019},
author = {Ansari, FA and Ahmad, I},
title = {Fluorescent Pseudomonas -FAP2 and Bacillus licheniformis interact positively in biofilm mode enhancing plant growth and photosynthetic attributes.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {4547},
doi = {10.1038/s41598-019-40864-4},
pmid = {30872708},
issn = {2045-2322},
abstract = {Compatible interaction between commonly used plant growth promoting rhizobacteria (PGPR) in biofilm mode in vitro and in the rhizosphere is expected to provide better understanding for the development of effective consortium. With the above hypothesis, the present study evaluated two characterized PGPR (Pseudomonas fluorescens FAP2 and Bacillus licheniformis B642) for their biofilm-related functions using standard protocols. The interaction between the FAP2 and B642 in planktonic mode was studied by plate spot/overlay method and competitive growth assessment. Biofilm development on a microtitre plate and a glass surface was studied by standard methods. Biofilm formation was characterized by SEM. Rhizosphere and rhizoplane colonization of wheat seedlings by both isolates individually and by co-inoculation was studied by determining CFU/g of soil/root samples. Biofilm development on the root surface was further analyzed by SEM. Both isolates demonstrated multiple plant growth promoting (PGP) traits (production of IAA, siderophore, and ammonia; phosphate solubilization) and biofilm-related functions such as production of EPS, alginate, cell surface hydrophobicity and swarming motility. Both strains formed strong biofilms on a glass cover slip in vitro. Interaction between the two strains under the planktonic mode revealed no antagonism in terms of growth inhibition and competitive growth kinetics. Similarly, FAP2 and B642 strains formed a mixed biofilm on a glass cover slip as well as on seedling roots. Wheat rhizosphere and rhizoplane were colonized by both isolates as evidenced from their viable counts in single and co-inoculation. The effect of single and co inoculation revealed the significant enhancement of vegetative growth and photosynthetic parameters such as chlorophyll content, transpiration rate (E), internal CO2 concentration (Ci), stomatal conductance (gs), and net photosynthetic rate (PN) and leaf water potential (LWP) as compared to uninoculated control. Indigenous Pseudomonas fluorescens FAP2 strain and Bacillus licheniformis B642 are compatible PGPR in both planktonic and biofilm modes of growth and threfore could be developed effective consortium of PGPR. Further indepth investigation is required to understand molecular mechanism of the interaction in biofilm mode of growth under natural condition.},
}
@article {pmid30872074,
year = {2019},
author = {Siddique, A and Suraraksa, B and Horprathum, M and Oaew, S and Cheunkar, S},
title = {Wastewater biofilm formation on self-assembled monolayer surfaces using elastomeric flow cells.},
journal = {Anaerobe},
volume = {57},
number = {},
pages = {11-18},
doi = {10.1016/j.anaerobe.2019.03.005},
pmid = {30872074},
issn = {1095-8274},
abstract = {In anaerobic wastewater treatment, microbial biofilm is beneficial for efficient substrate utilization and for preventing the wash-out of key microorganisms. By providing solid supports, biofilm formation can be accelerated due to the early initial adhesion of residing microbes. Alteration in surface properties is therefore one such approach that helps us understand microbial interfacial interaction. Here, self-assembled monolayers of alkanethiols with carboxyl (-COOH), hydroxyl (-OH), and amine (-NH2) terminal moieties on gold (Au) substrates were employed to study the initial adhesion of wastewater microbes. An elastomeric flow cell was also utilized to simulate the environment of wastewater bioreactor. Results from fluorescence in situ hybridization (FISH) portrayed more enhanced microbial adhesion after 2 h on -NH2 functional group with the calculated surface coverage of 12.8 ± 2.4% as compared to 7.7 ± 1.6% on -COOH, 11.0 ± 2.0% on -OH, and 1.2% on unmodified Au surfaces. This might be because of concomitant electrostatic attraction between negatively-charged bacteria and positively-charged (-NH3+) functional groups. Nevertheless, the average surface coverage by individual biofilm clusters was 28.0 ± 5.0 μm2 and 32.0 ± 9.0 μm2 on -NH2 and -OH surfaces, respectively, while -COOH surfaces resulted in higher value (60.0 ± 5.0 μm2) and no significant cluster formation was observed on Au surfaces. Accordingly, the average inter-cluster distance observed on -NH2 surfaces was relatively smaller (3.0 ± 0.6 μm) as compared to that on other surfaces. Overall, these data suggest favorable initial biofilm growth on more hydrophilic and positively-charged surfaces. Furthermore, the analysis of the mean fluorescence intensity revealed preferred initial adhesion of key microbes (archaea) on -OH and -NH2 surfaces. Indeed, results obtained from this study would be beneficial in designing selective biointerfaces for certain biofilm carriers in a typical wastewater bioreactor. Importantly, our elastomeric flow cell integrated with SAM-modified surfaces demonstrated an ideal platform for high-throughput investigation of wastewater biofilm under controlled environments.},
}
@article {pmid30871787,
year = {2019},
author = {Modiri, M and Khodavaisy, S and Barac, A and Akbari Dana, M and Nazemi, L and Aala, F and Salehi, M and Rezaie, S},
title = {Comparison of biofilm-producing ability of clinical isolates of Candida parapsilosis species complex.},
journal = {Journal de mycologie medicale},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.mycmed.2019.02.003},
pmid = {30871787},
issn = {1773-0449},
abstract = {OBJECTIVE: Candida parapsilosis is one of the main emerging non-Candida albicans species leading to superficial and systemic fungal infections in humans. Candida has the ability to produce biofilms associated with pathogenesis. The aim of the study was to estimate biofilm-producing ability of clinical isolates of C. parapsilosis sp. complex.<br><br>METHODS: Clinical samples of C. parapsilosis complex have been analyzed. Crystal violet (CV) staining and tetrazolium reduction assay (MTT) have been used to analyze the clinical isolates ability to produce biofilms. The biofilm's structural characteristics have been assessed by using scanning electron microscopy.<br><br>RESULTS: All 65 isolates were able to form biofilm. In addition, no significant difference was found between biofilm quantification based on two assays at different time intervals (24h, 48h, 72h, 96h) (P>0.05), with the exception of Candida orthopsilosis, which exhibited higher metabolic activity at 24h time point (P<0.05). Moreover, metabolic activity and production of biofilm biomass demonstrated statistically significant correlation (r=0.685, P<0.01). According to microscopic observations, the investigated clinical strains formed the similar surface topography with the slight differences in morphology; in addition, there was no statistically significant difference between efficiency of two assays to quantify biofilm.<br><br>CONCLUSION: It was shown that, similar to C. parapsilosissensu stricto, two cryptic identified species (C. orthopsilosis and Candida metapsilosis) obtained from different clinical samples, were biofilm producers, while C. parapsilosissensu stricto exhibited the highest biofilm production.},
}
@article {pmid30870985,
year = {2019},
author = {Henry, M and Fouladkhah, A},
title = {Outbreak History, Biofilm Formation, and Preventive Measures for Control of Cronobacter sakazakii in Infant Formula and Infant Care Settings.},
journal = {Microorganisms},
volume = {7},
number = {3},
pages = {},
doi = {10.3390/microorganisms7030077},
pmid = {30870985},
issn = {2076-2607},
abstract = {Previously known as Enterobacter sakazakii from 1980 to 2007, Cronobacter sakazakii is an opportunistic bacterium that survives and persists in dry and low-moisture environments, such as powdered infant formula. Although C. sakazakii causes disease in all age groups, infections caused by this pathogen are particularly fatal in infants born premature and those younger than two months. The pathogen has been isolated from various environments such as powdered infant formula manufacturing facilities, healthcare settings, and domestic environments, increasing the chance of infection through cross-contamination. The current study discusses the outbreak history of C. sakazakii and the ability of the microorganism to produce biofilms on biotic and abiotic surfaces. The study further discusses the fate of the pathogen in low-moisture environments, articulates preventive measures for healthcare providers and nursing parents, and delineates interventions that could be utilized in infant formula manufacturing to minimize the risk of contamination with Cronobacter sakazakii.},
}
@article {pmid30870530,
year = {2019},
author = {Schoenfelder, SMK and Lange, C and Prakash, SA and Marincola, G and Lerch, MF and Wencker, FDR and Förstner, KU and Sharma, CM and Ziebuhr, W},
title = {The small non-coding RNA RsaE influences extracellular matrix composition in Staphylococcus epidermidis biofilm communities.},
journal = {PLoS pathogens},
volume = {15},
number = {3},
pages = {e1007618},
doi = {10.1371/journal.ppat.1007618},
pmid = {30870530},
issn = {1553-7374},
mesh = {Bacterial Proteins/genetics/metabolism ; Biofilms ; Extracellular Matrix/*genetics/physiology ; Gene Expression Profiling ; Gene Expression Regulation, Bacterial/genetics ; Operon/genetics ; Phenotype ; Polysaccharides, Bacterial/genetics/metabolism ; RNA, Small Untranslated/genetics/*metabolism ; Staphylococcal Infections/genetics/metabolism ; Staphylococcus/genetics ; Staphylococcus epidermidis/*genetics/metabolism ; },
abstract = {RsaE is a conserved small regulatory RNA (sRNA) which was previously reported to represent a riboregulator of central carbon flow and other metabolic pathways in Staphylococcus aureus and Bacillus subtilis. Here we show that RsaE contributes to extracellular (e)DNA release and biofilm-matrix switching towards polysaccharide intercellular adhesin (PIA) production in a hypervariable Staphylococcus epidermidis isolate. Transcriptome analysis through differential RNA sequencing (dRNA-seq) in combination with confocal laser scanning microscopy (CLSM) and reporter gene fusions demonstrate that S. epidermidis protein- and PIA-biofilm matrix producers differ with respect to RsaE and metabolic gene expression. RsaE is spatiotemporally expressed within S. epidermidis PIA-mediated biofilms, and its overexpression triggers a PIA biofilm phenotype as well as eDNA release in an S. epidermidis protein biofilm matrix-producing strain background. dRNA-seq and Northern blot analyses revealed RsaE to exist as a major full-length 100-nt transcript and a minor processed species lacking approximately 20 nucleotides at the 5'-end. RsaE processing results in expansion of the mRNA target spectrum. Thus, full-length RsaE interacts with S. epidermidis antiholin-encoding lrgA mRNA, facilitating bacterial lysis and eDNA release. Processed RsaE, however, interacts with the 5'-UTR of icaR and sucCD mRNAs, encoding the icaADBC biofilm operon repressor IcaR and succinyl-CoA synthetase of the tricarboxylic acid (TCA) cycle, respectively. RsaE augments PIA-mediated biofilm matrix production, most likely through activation of icaADBC operon expression via repression of icaR as well as by TCA cycle inhibition and re-programming of staphylococcal central carbon metabolism towards PIA precursor synthesis. Additionally, RsaE supports biofilm formation by mediating the release of eDNA as stabilizing biofilm matrix component. As RsaE itself is heterogeneously expressed within biofilms, we consider this sRNA to function as a factor favoring phenotypic heterogeneity and supporting division of labor in S. epidermidis biofilm communities.},
}
@article {pmid30870411,
year = {2019},
author = {Williams, DL and Smith, SR and Peterson, BR and Allyn, G and Cadenas, L and Epperson, RT and Looper, RE},
title = {Growth substrate may influence biofilm susceptibility to antibiotics.},
journal = {PloS one},
volume = {14},
number = {3},
pages = {e0206774},
doi = {10.1371/journal.pone.0206774},
pmid = {30870411},
issn = {1932-6203},
support = {I01 RX001198/RX/RRD VA/United States ; I01 RX002287/RX/RRD VA/United States ; },
abstract = {The CDC biofilm reactor is a robust culture system with high reproducibility in which biofilms can be grown for a wide variety of analyses. Multiple material types are available as growth substrates, yet data from biofilms grown on biologically relevant materials is scarce, particularly for antibiotic efficacy against differentially supported biofilms. In this study, CDC reactor holders were modified to allow growth of biofilms on collagen, a biologically relevant substrate. Susceptibility to multiple antibiotics was compared between biofilms of varying species grown on collagen versus standard polycarbonate coupons. Data indicated that in 13/18 instances, biofilms on polycarbonate were more susceptible to antibiotics than those on collagen, suggesting that when grown on a complex substrate, biofilms may be more tolerant to antibiotics. These outcomes may influence the translatability of antibiotic susceptibility profiles that have been collected for biofilms on hard plastic materials. Data may also help to advance information on antibiotic susceptibility testing of biofilms grown on biologically relevant materials for future in vitro and in vivo applications.},
}
@article {pmid30869588,
year = {2018},
author = {Vinson, LA and Gilbert, PR and Sanders, BJ and Moser, E and Gregory, RL},
title = {Silver Diamine Fluoride and Potassium Iodide Disruption of In Vitro Streptococcus mutans Biofilm.},
journal = {Journal of dentistry for children (Chicago, Ill.)},
volume = {85},
number = {3},
pages = {120-124},
pmid = {30869588},
issn = {1935-5068},
abstract = {Purpose: The purpose of this study was to investigate the inhibitory in vitro effects of silver diamine fluoride (SDF) with and without a saturated solution of potassium iodide (SSKI) on established Streptococcus mutans biofilm.Methods: Fifty μl of an overnight S. mutans culture (106 CFU per mL) in Tryptic Soy Broth (TSB) and three ml of fresh TSB supplemented with one percent sucrose (TSBS) were incubated for 24 hours to establish an S. mutans biofilm in six-well tissue culture plates. Four treatments (SDF, SSKI, SDF plus SSKI, and untreated control) were used to disrupt the biofilm. The biofilm groups were each treated with reagent and washed; the biofilm was collected, diluted, and spiral-plated onto blood agar plates; and an automated counting machine was used to determine the bacterial colony forming units (CFU).Results: The control had significantly more CFU than the SSKI, SDF, and SDF plus SSKI groups (P<.0001). The SSKI group had significantly more CFU than the SDF and SDF plus SSKI groups (P<.0001). The SDF group had significantly fewer CFU than the SDF plus SSKI group (P=.02). The reduction from the control was more than seven-fold for SDF, four-fold for SDF plus SSKI, and two-fold for SSKI.Conclusions: SDF alone, SDF plus SSKI, and SSKI disrupted an established S. mutans biofilm. SDF alone had the greatest overall disruption.},
}
@article {pmid30868761,
year = {2019},
author = {Roche, ED and Woodmansey, EJ and Yang, Q and Gibson, DJ and Zhang, H and Schultz, GS},
title = {Cadexomer iodine effectively reduces bacterial biofilm in porcine wounds ex vivo and in vivo.},
journal = {International wound journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/iwj.13080},
pmid = {30868761},
issn = {1742-481X},
support = {//Smith &amp; Nephew plc/ ; },
abstract = {Biofilms are prevalent in non-healing chronic wounds and implicated in delayed healing. Tolerance to antimicrobial treatments and the host's immune system leave clinicians with limited interventions against biofilm populations. It is therefore essential that effective treatments be rigorously tested and demonstrate an impact on biofilm across multiple experimental models to guide clinical investigations and protocols. Cadexomer iodine has previously been shown to be effective against biofilm in various in vitro models, against methicillin-resistant Staphylococcus aureus biofilm in mouse wounds, and clinically in diabetic foot ulcers complicated by biofilm. Similarities between porcine and human skin make the pig a favoured model for cutaneous wound studies. Two antiseptic dressings and a gauze control were assessed against mature biofilm grown on ex vivo pig skin and in a pig wound model. Significant reductions in biofilm were observed following treatment with cadexomer iodine across both biofilm models. In contrast, silver carboxymethylcellulose dressings had minimal impact on biofilm in the models, with similar results to the control in the ex vivo model. Microscopy and histopathology indicate that the depth of organisms in wound tissue may impact treatment effectiveness. Further work on the promising biofilm efficacy of cadexomer iodine is needed to determine optimal treatment durations against biofilm.},
}
@article {pmid30868754,
year = {2019},
author = {Parnasa, R and Sendersky, E and Simkovsky, R and Waldman Ben-Asher, H and Golden, SS and Schwarz, R},
title = {A microcin processing peptidase-like protein of the cyanobacterium Synechococcus elongatus is essential for secretion of biofilm-promoting proteins.},
journal = {Environmental microbiology reports},
volume = {},
number = {},
pages = {},
doi = {10.1111/1758-2229.12751},
pmid = {30868754},
issn = {1758-2229},
support = {//National Science Foundation/ ; NSF-BSF 2012823//US-Israel Binational Science Foundation/ ; ISF 1406/14//Israel Science Foundation/ ; },
abstract = {Small secreted compounds, e.g. microcins, are characterized by a double-glycine (GG) secretion motif that is cleaved off upon maturation. Genomic analysis suggests that small proteins that possess a GG motif are widespread in cyanobacteria; however, the roles of these proteins are largely unknown. Using a biofilm-proficient mutant of the cyanobacterium Synechococcus elongatus PCC 7942 in which the constitutive biofilm self-suppression mechanism is inactivated, we previously demonstrated that four small proteins, Enable biofilm formation with a GG motif (EbfG1-4), each with a GG motif, enable biofilm formation. Furthermore, a peptidase belonging to the C39 family, Peptidase transporter enabling Biofilm (PteB), is required for secretion of these proteins. Here, we show that the microcin processing peptidase-like protein encoded by gene Synpcc7942_1127 is also required for biofilm development - inactivation of this gene in the biofilm-proficient mutant abrogates biofilm development. Additionally, this peptidase-like protein (denoted EbfE - enables biofilm formation peptidase) is required for secretion of the EbfG biofilm-promoting small proteins. Given their protein-domain characteristics, we suggest that PteB and EbfE take part in a maturation-secretion system, with PteB being located to the cell membrane while EbfE is directed to the periplasmic space via its secretion signal.},
}
@article {pmid30867692,
year = {2019},
author = {Yu, Z and Kong, Y and Luo, Z and Liu, T and Lin, J},
title = {Anti-bacterial activity of mutant chensinin-1 peptide against multidrug-resistant Pseudomonas aeruginosa and its effects on biofilm-associated gene expression.},
journal = {Experimental and therapeutic medicine},
volume = {17},
number = {3},
pages = {2031-2038},
doi = {10.3892/etm.2019.7182},
pmid = {30867692},
issn = {1792-0981},
abstract = {Nosocomial infections with Pseudomonas aeruginosa (PA) are difficult to treat due to the low outer membrane permeability of the bacterium and the development of resistance. In the present study, the anti-microbial peptide (AMP) mutant chensinin-1 (MC1) was revealed to exhibit anti-bacterial activity against a multidrug-resistant PA (MRPA) strain in vitro, and the minimum inhibitory concentration was 25 µM, which was 4-fold higher than that of the native strain. MC1 was able to disrupt the integrity of the cytoplasmic membrane in the native PA strain and MRPA and had a similar membrane depolarization ability in these strains, but the outer membrane permeability of MRPA cells was lower than that of native PA cells, as determined by a 1-N-phenylnaphthylamine assay. In addition, the abundance of the gene Psl encoding for biofilm-associated polysaccharides was detected using Congo red, and a high concentration of MC1 inhibited the formation of MRPA biofilms. Furthermore, the expression levels of biofilm-associated genes affected by the AMP, MC1, were quantified by polymerase chain reaction analysis. The results indicated that MC1 induced biofilm inhibition by downregulating the relative expression of specific biofilm polysaccharide-associated genes, including pelA, algD and pslA. The present results indicated that the AMP MC1 may be an effective antibiotic against MRPA strains.},
}
@article {pmid30867546,
year = {2019},
author = {Smith, AR and Kieft, B and Mueller, R and Fisk, MR and Mason, OU and Popa, R and Colwell, FS},
title = {Carbon fixation and energy metabolisms of a subseafloor olivine biofilm.},
journal = {The ISME journal},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41396-019-0385-0},
pmid = {30867546},
issn = {1751-7370},
abstract = {Earth's largest aquifer ecosystem resides in igneous oceanic crust, where chemosynthesis and water-rock reactions provide the carbon and energy that support an active deep biosphere. The Calvin Cycle is the predominant carbon fixation pathway in cool, oxic, crust; however, the energy and carbon metabolisms in the deep thermal basaltic aquifer are poorly understood. Anaerobic carbon fixation pathways such as the Wood-Ljungdahl pathway, which uses hydrogen (H2) and CO2, may be common in thermal aquifers since water-rock reactions can produce H2 in hydrothermal environments and bicarbonate is abundant in seawater. To test this, we reconstructed the metabolisms of eleven bacterial and archaeal metagenome-assembled genomes from an olivine biofilm obtained from a Juan de Fuca Ridge basaltic aquifer. We found that the dominant carbon fixation pathway was the Wood-Ljungdahl pathway, which was present in seven of the eight bacterial genomes. Anaerobic respiration appears to be driven by sulfate reduction, and one bacterial genome contained a complete nitrogen fixation pathway. This study reveals the potential pathways for carbon and energy flux in the deep anoxic thermal aquifer ecosystem, and suggests that ancient H2-based chemolithoautotrophy, which once dominated Earth's early biosphere, may thus remain one of the dominant metabolisms in the suboceanic aquifer today.},
}
@article {pmid30867500,
year = {2019},
author = {Bartnicka, D and Karkowska-Kuleta, J and Zawrotniak, M and Satała, D and Michalik, K and Zielinska, G and Bochenska, O and Kozik, A and Ciaston, I and Koziel, J and Dutton, LC and Nobbs, AH and Potempa, B and Baster, Z and Rajfur, Z and Potempa, J and Rapala-Kozik, M},
title = {Adhesive protein-mediated cross-talk between Candida albicans and Porphyromonas gingivalis in dual species biofilm protects the anaerobic bacterium in unfavorable oxic environment.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {4376},
doi = {10.1038/s41598-019-40771-8},
pmid = {30867500},
issn = {2045-2322},
abstract = {The oral cavity contains different types of microbial species that colonize human host via extensive cell-to-cell interactions and biofilm formation. Candida albicans-a yeast-like fungus that inhabits mucosal surfaces-is also a significant colonizer of subgingival sites in patients with chronic periodontitis. It is notable however that one of the main infectious agents that causes periodontal disease is an anaerobic bacterium-Porphyromonas gingivalis. In our study, we evaluated the different strategies of both pathogens in the mutual colonization of an artificial surface and confirmed that a protective environment existed for P. gingivalis within developed fungal biofilm formed under oxic conditions where fungal cells grow mainly in their filamentous form i.e. hyphae. A direct physical contact between fungi and P. gingivalis was initiated via a modulation of gene expression for the major fungal cell surface adhesin Als3 and the aspartic proteases Sap6 and Sap9. Proteomic identification of the fungal surfaceome suggested also an involvement of the Mp65 adhesin and a &quot;moonlighting&quot; protein, enolase, as partners for the interaction with P. gingivalis. Using mutant strains of these bacteria that are defective in the production of the gingipains-the proteolytic enzymes that also harbor hemagglutinin domains-significant roles of these proteins in the formation of bacteria-protecting biofilm were clearly demonstrated.},
}
@article {pmid30866810,
year = {2019},
author = {Sánchez, MC and Romero-Lastra, P and Ribeiro-Vidal, H and Llama-Palacios, A and Figuero, E and Herrera, D and Sanz, M},
title = {Comparative gene expression analysis of planktonic Porphyromonas gingivalis ATCC 33277 in the presence of a growing biofilm versus planktonic cells.},
journal = {BMC microbiology},
volume = {19},
number = {1},
pages = {58},
doi = {10.1186/s12866-019-1423-9},
pmid = {30866810},
issn = {1471-2180},
abstract = {BACKGROUND: Porphyromonas gingivalis, a microorganism residing in the oral cavity within complex multispecies biofilms, is one of the keystone pathogens in the onset and progression of periodontitis. In this in vitro study, using DNA microarray, we investigate the differential gene expression of Porphyromonas gingivalis ATCC 33277 when growing in the presence or in absence of its own monospecies biofilm.<br><br>RESULTS: Approximately 1.5% of genes (28 out of 1909 genes, at 1.5 fold change or more, p-value < 0.05) were differentially expressed by P. gingivalis cells when in the presence of a biofilm. These genes were predominantly related to the metabolism of iron, bacterial adhesion, invasion, virulence and quorum-sensing system. The results from microarrays were consistent with those obtained by RT-qPCR.<br><br>CONCLUSION: This study provides insight on the transcriptional changes of planktonic P. gingivalis cells when growing in the presence of a biofilm. The resulting phenotypes provide information on changes occurring in the gene expression of this pathogen.},
}
@article {pmid30866438,
year = {2019},
author = {Corte, L and Casagrande Pierantoni, D and Tascini, C and Roscini, L and Cardinali, G},
title = {Biofilm Specific Activity: A Measure to Quantify Microbial Biofilm.},
journal = {Microorganisms},
volume = {7},
number = {3},
pages = {},
doi = {10.3390/microorganisms7030073},
pmid = {30866438},
issn = {2076-2607},
abstract = {Microbes growing onto solid surfaces form complex 3-D biofilm structures characterized by the production of extracellular polymeric compounds and an increased resistance to drugs. The quantification of biofilm relays currently on a number of different approaches and techniques, often leading to different evaluations of the ability to form biofilms of the studied microbial strains. Measures of biofilm biomass were carried out with crystal violet (CV) and a direct reading at 405 nm, whereas the activity was assessed with the XTT ((2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) method. The strains of four pathogenic species of the genus Candida (C. albicans, C. glabrata, C. parapsilosis and C. tropicalis) and of Staphylococcus aureus were employed to determine the effective relatedness among techniques and the specific activity of the biofilm, as a ratio between the XTT and the CV outcomes. Since the ability to form biomass and to be metabolically active are not highly related, their simultaneous use allowed for a categorization of the strains. This classification is putatively amenable of further study by comparing the biofilm type and the medical behavior of the strains.},
}
@article {pmid30865550,
year = {2019},
author = {Szell, T and Dressler, FF and Goelz, H and Bluemel, B and Miernik, A and Brandstetter, T and Scherag, F and Schoeb, DS},
title = {Response to Tailly and Van Haute: In Vitro Effects of a Novel Coating Agent on Bacterial Biofilm Development on Ureteral Stent by Schoeb et al. (From: Tailly T, Van Haute C. J Endourol 2019;33:232-233; DOI: 10.1089/end.2018.0907).},
journal = {Journal of endourology},
volume = {33},
number = {3},
pages = {234},
doi = {10.1089/end.2019.29052.tsz},
pmid = {30865550},
issn = {1557-900X},
}
@article {pmid30865048,
year = {2019},
author = {Córdoba, A and Graue-Hernandez, EO and Bermudez-Magner, JA and Ramirez-Miranda, A and Irusteta, L and Bautista-de Lucio, VM and Ponce-Angulo, DG and Bautista-Hernandez, LA and Navas, A},
title = {Corneal Biofilm Plaques: A Novel Clinical Presentation.},
journal = {Cornea},
volume = {},
number = {},
pages = {},
doi = {10.1097/ICO.0000000000001923},
pmid = {30865048},
issn = {1536-4798},
abstract = {PURPOSE: To report a novel clinical presentation of corneal biofilms, consisting of formation of superficial and recurrent corneal plaques.<br><br>METHODS: Interventional case report. A 9-year-old boy presented with subepithelial, whitish, avascular, and recurrent corneal plaques without any clinical manifestations of active corneal inflammation and/or infection. He had a history of minor ocular trauma; otherwise, his medical history was unremarkable.<br><br>RESULTS: An excisional biopsy was performed under topical anesthesia. Histological analysis identified these plaques as clusters of gram-negative bacilli surrounded by an extracellular matrix. Samples were further evaluated with special stains (calcofluor white, Flamingo fluorescent dye, propidium iodide, and Gomori-Grocott) that demonstrated biofilm structures.<br><br>CONCLUSIONS: Corneal plaques are a very rare clinical presentation of corneal biofilms that allow prolonged survival of microorganisms even in the absence of prosthetic material and clinical signs or symptoms of corneal active inflammation and/or infection.},
}
@article {pmid30864645,
year = {2019},
author = {Rezende, G and Arthur, RA and Lamers, ML and Hashizume, LN},
title = {Structural Organization of Dental Biofilm Formed in situ in the Presence of Sucrose Associated to Maltodextrin.},
journal = {Brazilian dental journal},
volume = {30},
number = {1},
pages = {36-42},
doi = {10.1590/0103-6440201902183},
pmid = {30864645},
issn = {1806-4760},
abstract = {Maltodextrins, derived from corn starch, have been added to industrialized food combined with sucrose. However it is not clear the diffusion properties of the dental biofilm matrix and the tridimensional structure of multispecies biofilms formed in the presence of these carbohydrates. Therefore, the aim of study was to investigate by confocal laser scanning microscopy (CLSM) the structural organization of the multispecies dental biofilm formed in situ under exposure to sucrose associated to maltodextrin. Adult volunteers wore an intraoral palatal appliance containing bovine enamel blocks. They were instructed to remove the appliance 8 times per day and drop the following solutions on the enamel blocks: deionized distilled water (DDW), maltodextrin, sucrose + maltodextrin or sucrose. Biofilms formed were stained and the percentage of extracellular polysaccharide (%EPS) and thickness were determined by CLSM. Biofilm formed in the presence of sucrose and sucrose + maltodextrin presented similar %EPS and higher than DDW and maltodextrin. Regarding to the biofilm thickness, sucrose and sucrose + maltodextrin treatments were thicker than DDW and maltodextrin and similar between them. The structural organization of the multispecies dental biofilm formed in situ in the presence of sucrose does not change when this carbohydrate is associated to maltodextrin.},
}
@article {pmid30863390,
year = {2019},
author = {Peel, TN},
title = {Studying Biofilm and Clinical Issues in Orthopedics.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {359},
doi = {10.3389/fmicb.2019.00359},
pmid = {30863390},
issn = {1664-302X},
abstract = {The association between biofilm-forming microorganisms and prosthetic joint infection influences all aspect of management including approaches to diagnosis, management and prevention. This article will provide an overview of new anti-biofilm strategies for management of prosthetic joint infection.},
}
@article {pmid30862561,
year = {2019},
author = {Lopes, LQS and de Almeida Vaucher, R and Giongo, JL and Gündel, A and Santos, RCV},
title = {Characterisation and anti-biofilm activity of glycerol monolaurate nanocapsules against Pseudomonas aeruginosa.},
journal = {Microbial pathogenesis},
volume = {130},
number = {},
pages = {178-185},
doi = {10.1016/j.micpath.2019.03.007},
pmid = {30862561},
issn = {1096-1208},
abstract = {Pseudomonas aeruginosa is a ubiquitous microorganism that commonly causes hospital-acquired infections, including pneumonia, bloodstream and urinary tract infections and it is well known for chronically colonising the respiratory tract of patients with cystic fibrosis, causing severe intermittent exacerbation of the condition. P. aeruginosa may appear in the free form cell but also grows in biofilm communities adhered to a surface. An alternative to conventional antimicrobial agents are nanoparticles that can act as carriers for antibiotics and other drugs. In this context, the study aimed to characterise and verify the anti-biofilm potential of GML Nanocapsules against P. aeruginosa. The nanocapsules showed a mean diameter of 190.7 nm, polydispersion index of 0.069, the zeta potential of -23.3 mV. The microdilution test showed a MIC of 62.5 μg/mL to GML and 15.62 μg/mL to GML Nanocapsules. The anti-biofilm experiments demonstrated the significant reduction of biomass, proteins, polysaccharide and viable P. aeruginosa in biofilm treated with GML Nanocapsules while the free GML did not cause an effect. The AFM images showed a decrease in a biofilm which received GML. The positive results suggest an alternative for the public health trouble related to infections associated with biofilm.},
}
@article {pmid30861212,
year = {2019},
author = {Kugaji, MS and Kumbar, VM and Peram, MR and Patil, S and Bhat, KG and Diwan, PV},
title = {Effect of Resveratrol on biofilm formation and virulence factor gene expression of Porphyromonas gingivalis in periodontal disease.},
journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica},
volume = {127},
number = {4},
pages = {187-195},
doi = {10.1111/apm.12930},
pmid = {30861212},
issn = {1600-0463},
mesh = {Adhesins, Bacterial/analysis ; Anti-Bacterial Agents/*pharmacology ; Bacteroidaceae Infections/microbiology ; Biofilms/*drug effects ; Cysteine Endopeptidases/analysis ; Fimbriae Proteins/analysis ; Gene Expression Profiling ; Gentian Violet/analysis ; Humans ; Microbial Sensitivity Tests ; Periodontal Diseases/microbiology ; Porphyromonas gingivalis/*drug effects/isolation &amp; purification ; Resveratrol/*pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; Staining and Labeling ; Virulence Factors/*antagonists &amp; inhibitors ; },
abstract = {Periodontal disease is an oral inflammatory disease that destroys the tooth supporting periodontal tissues resulting in tooth loss. Porphyromonas gingivalis is a keystone pathogen that plays a significant role in periodontitis. In previous studies, resveratrol has shown significant results by targeting inflammatory and adhesive markers. Virulence factors of P. gingivalis play an important role in the bacterial adhesion and colonization. In this study, we aimed to demonstrate the anti-biofilm and anti-bacterial activity of resveratrol and also study the effect of resveratrol on the expression of virulence factor genes of P. gingivalis using reverse transcriptase polymerase chain reaction (RT-PCR). The anti-microbial and anti-biofilm activity of resveratrol on P. gingivalis was carried out by broth microdilution assay and biofilm adhesion reduction-crystal violet assay, respectively. We carried out the gene expression analysis by RT-PCR with the P. gingivalis treated compound to analyze the change in the expression of virulence factors: fimbriae and gingipain. Minimal inhibitory concentrations (MIC) of resveratrol against P. gingivalis and other clinical strains are in the range of 78.12-156.25 μg/mL. Resveratrol dose-dependently prevented the biofilm formation and also attenuated the virulence of P. gingivalis by reducing the expression of virulence factor genes such as fimbriae (type II and IV) and proteinases (kgp and rgpA). Resveratrol demonstrated superior anti-bacterial and anti-biofilm activity against P. gingivalis. There was significant reduction in the expression of fimbriae and gingipain with the resveratrol-treated compound. The results suggest that resveratrol, due to its multiple actions, may become a simple and inexpensive therapeutic strategy for treating periodontal disease.},
}
@article {pmid30860848,
year = {2019},
author = {de Miguel, I and Prieto, I and Albornoz, A and Sanz, V and Weis, C and Turon, P and Quidant, R},
title = {Plasmon-Based Biofilm Inhibition on Surgical Implants.},
journal = {Nano letters},
volume = {19},
number = {4},
pages = {2524-2529},
doi = {10.1021/acs.nanolett.9b00187},
pmid = {30860848},
issn = {1530-6992},
abstract = {The insertion of an implant in the body of a patient raises the risk of a posterior infection and formation of a biofilm, which can have critical consequences on the patient's health and be associated with a high sanitary cost. While antibacterial agents can be used to prevent the infection, such a strategy is time-limited and causes bacteria resistance. As an alternative to biochemical approaches, we propose here to use light-induced local hyperthermia with plasmonic nanoparticles. This strategy is implemented on surgical meshes, extensively used in the context of hernia repairing, one of the most common general surgeries. Surgical meshes were homogeneously coated with gold nanorods designed to efficiently convert near-infrared light into heat. The modified mesh was exposed to a biofilm of Staphylococcus aureus (S. aureus) bacteria before being treated with a train of light pulses. We systematically study how the illumination parameters, namely fluence, peak intensity and pulse length, influence the elimination of attached bacteria. Additionally, fluorescence confocal microscopy provides us some insight on the mechanism involved in the degradation of the biofilm. This proof-of-principle study opens a new set of opportunities for the development of novel disinfection approaches combining light and nanotechnology.},
}
@article {pmid30858842,
year = {2019},
author = {Butini, ME and Abbandonato, G and Di Rienzo, C and Trampuz, A and Di Luca, M},
title = {Isothermal Microcalorimetry Detects the Presence of Persister Cells in a Staphylococcus aureus Biofilm After Vancomycin Treatment.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {332},
doi = {10.3389/fmicb.2019.00332},
pmid = {30858842},
issn = {1664-302X},
abstract = {Staphylococcus aureus biofilm plays a major role in implant-associated infections. Here, the susceptibility of biofilm S. aureus to daptomycin, fosfomycin, vancomycin, trimethoprim/sulfamethoxazole, linezolid, and rifampicin was investigated by isothermal microcalorimetry (IMC). Moreover, the persister status of cells isolated from S. aureus biofilm after treatment with vancomycin was also analyzed. S. aureus biofilm was tolerant to all the antibiotics tested [minimum biofilm bactericidal concentration (MBBC) > 256 μg/ml], except to daptomycin [MBBC and minimum biofilm eradicating concentration (MBEC) = 32 μg/ml] and rifampin (MBBC and MBEC = 128 μg/ml). After the treatment of MRSA biofilm with 1024 μg/ml vancomycin, ∼5% cells survived, although metabolically inactive (persisters). Interestingly, IMC revealed that persister bacteria reverted to a normal-growing phenotype when inoculated into fresh medium without antibiotics. A staggered treatment of MRSA biofilm with vancomycin to kill all the metabolically active cells and daptomycin to kill persister cells eradicated the whole bacterial population. These results support the use in the clinical practice of a therapeutic regimen based on the use of two antibiotics to kill persister cells and eradicate MRSA biofilms. IMC represents a suitable technique to characterize in real-time the reversion from persister to metabolically-active cells.},
}
@article {pmid30858304,
year = {2019},
author = {Valle, J and Echeverz, M and Lasa, I},
title = {σB inhibits PNAG exopolysaccharide synthesis and biofilm formation in Staphylococcus aureus.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00098-19},
pmid = {30858304},
issn = {1098-5530},
abstract = {Staphylococcus aureus clinical strains are able to produce at least two distinct types of biofilm matrixes: biofilm matrixes made of PIA/PNAG exopolysaccharide whose synthesis is mediated by the icaADBC locus, and biofilm matrixes built of proteins (polysaccharide-independent). σB is a conserved alternative sigma factor that regulates the expression of more than a hundred genes in response to changes in environmental conditions. While numerous studies agree that σB is required for polysaccharide-independent biofilms, a controversy persists over the role of σB in the regulation of PIA/PNAG dependent biofilm development. Here, we showed that genetically unrelated S. aureus σB deficient strains produced stronger biofilms both in static and flow conditions and accumulated higher levels of PIA/PNAG exopolysaccharide than their corresponding wild type strains. The increased accumulation of PIA/PNAG in the σB mutants correlated with a higher accumulation of the IcaC protein that it is not due to adjustments in icaADBC operon transcription and/or icaADBC mRNA stability. Overall, our results reveal that in the presence of an active σB, the turnover of Ica proteins is accelerated reducing the synthesis of PIA/PNAG exopolysaccharide and consequently the PIA/PNAG dependent biofilm formation capacity.IMPORTANCE Due to its multifaceted lifestyle Staphylococcus aureus needs a complex regulatory network to connect environmental signals with cellular physiology. One particular transcription factor, named σB (SigB), is involved in the general stress response and the expression of virulence factors. For many years, a great confusion has existed about the role of σB in the regulation of the biofilm lifestyle in S. aureus Our study demonstrated that σB is not necessary for exopolysaccharide-dependent biofilms and even more, that S. aureus produce stronger biofilms in the absence of σB The increased accumulation of exopolysaccharide correlates with a higher stability of the proteins responsible for its synthesis. The present findings reveal an additional regulatory layer to control biofilm exopolysaccharide synthesis under stress conditions.},
}
@article {pmid30858288,
year = {2019},
author = {Wong, SS and Lau, WY and Chan, PK and Wan, CK and Cheng, YL},
title = {Extended Experience in the Use of Antibiotic Lock for Eradication of Biofilm Bacteria on Tenckhoff Catheter.},
journal = {Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis},
volume = {39},
number = {2},
pages = {187-190},
doi = {10.3747/pdi.2018.00098},
pmid = {30858288},
issn = {1718-4304},
abstract = {Whilst antibiotic lock is effective to eradicate biofilm bacteria on hemodialysis catheters, this adjunctive method has scarcely been tested in peritoneal dialysis (PD) patients. After our previous successful experience of its use to salvage two Tenckhoff catheters, we encountered another patient with problematic biofilm-associated PD peritonitis who strongly refused catheter removal. As a result, antibiotic lock was given once daily, initially, with continuation of the usual PD schedule. However, relapsing peritonitis could not be prevented until we administered antibiotic lock without dialysate in the abdomen, which led to successful eradication of biofilm bacteria. To investigate the significance of having &quot;dry abdomen&quot; during antibiotic lock treatment, we injected an equivalent amount of contrast into the Tenckhoff catheter under fluoroscopy. We observed that the catheter lock solution could be retained over a long period of time only with &quot;dry abdomen,&quot; whereas rapid dissipation of the lock solution occurred in the presence of dialysate. We concluded that whilst antibiotic lock in a once-daily regimen can be highly effective against biofilm bacteria on a Tenckhoff catheter, it is essential to withhold PD exchanges during the dwell of antibiotic lock to prevent it from dissolving into the surrounding dialysate.},
}
@article {pmid30856522,
year = {2019},
author = {Di Tommaso, C and Taylor-Edmonds, L and Andrews, SA and Andrews, RC},
title = {The contribution of biofilm to nitrogenous disinfection by-product formation in full-scale cyclically-operated drinking water biofilters.},
journal = {Water research},
volume = {155},
number = {},
pages = {403-409},
doi = {10.1016/j.watres.2019.02.025},
pmid = {30856522},
issn = {1879-2448},
abstract = {Biofiltration has been shown to be effective for disinfection by-product (DBP) precursor control, however few studies have considered its role in the potential formation of DBPs. Biofilm is composed of heterogeneous bacteria as well as extracellular polymeric substances (EPS). The objective of this study was to determine the contribution of biofilm-related materials such as EPS to form nitrogen-containing DBPs upon chloramination, and to determine the influence of cyclical (scheduled on-off) biofilter operation on DBP precursor removal. Biologically active media was sampled from a full-scale biofilter operating under cold-water conditions (3.6 ± 0.5 °C) and extracted using a cation exchange resin into a phosphate buffer solution. Biomass concentrations, as determined using adenosine triphosphate (ATP) measurements, remained stable at 298 ± 55 ng ATP/g media over the trial period. N-nitrosodimethylamine (NDMA) and haloacetonitrile (HAN4) formation potential (FP) tests conducted under uniform formation conditions (UFC) using extracted biofilm yielded 0.80 ± 0.27 ng NDMA/g media and 18.7 ± 3.3 ng dichloroacetonitrile (DCAN)/g media. Further analyses of extracted biofilm using fluorescence spectroscopy and liquid chromatography-organic carbon detection indicated the presence of proteins above 20 kDa and humic-like substances. Extracted proteins (93.5 ± 8.1 μg/g media) correlated well (R = 0.90) with UV 280 measurements, indicating that spectrophotometry may serve as a valuable tool to quantify proteins in extracted biofilms. While substances in biofilms can serve as NDMA and DCAN precursors, the full-scale cyclically-operated biofilter that was examined did not show release of NDMA precursors during start-up following stagnation periods of 6 h or more. These biofilters consistently removed 6.9 ± 4.3 ng/L of NDMA precursors; typical NDMA UFC-FP of biofilter effluent was 8.5 ± 2.6 ng/L.},
}
@article {pmid30856240,
year = {2019},
author = {Pakkulnan, R and Anutrakunchai, C and Kanthawong, S and Taweechaisupapong, S and Chareonsudjai, P and Chareonsudjai, S},
title = {Extracellular DNA facilitates bacterial adhesion during Burkholderia pseudomallei biofilm formation.},
journal = {PloS one},
volume = {14},
number = {3},
pages = {e0213288},
doi = {10.1371/journal.pone.0213288},
pmid = {30856240},
issn = {1932-6203},
abstract = {The biofilm-forming ability of Burkholderia pseudomallei is crucial for its survival in unsuitable environments and is correlated with antibiotic resistance and relapsing cases of melioidosis. Extracellular DNA (eDNA) is an essential component for biofilm development and maturation in many bacteria. The aim of this study was to investigate the eDNA released by B. pseudomallei during biofilm formation using DNase treatment. The extent of biofilm formation and quantity of eDNA were assessed by crystal-violet staining and fluorescent dye-based quantification, respectively, and visualized by confocal laser scanning microscopy (CLSM). Variation in B. pseudomallei biofilm formation and eDNA quantity was demonstrated among isolates. CLSM images of biofilms stained with FITC-ConA (biofilm) and TOTO-3 (eDNA) revealed the localization of eDNA in the biofilm matrix. A positive correlation of biofilm biomass with quantity of eDNA during the 2-day biofilm-formation observation period was found. The increasing eDNA quantity over time, despite constant living/dead ratios of bacterial cells during the experiment suggests that eDNA is delivered from living bacterial cells. CLSM images demonstrated that depletion of eDNA by DNase I significantly lessened bacterial attachment (if DNase added at 0 h) and biofilm developing stages (if added at 24 h) but had no effect on mature biofilm (if added at 45 h). Collectively, our results reveal that eDNA is released from living B. pseudomallei and is correlated with biofilm formation. It was also apparent that eDNA is essential during bacterial cell attachment and biofilm-forming steps. The depletion of eDNA by DNase may provide an option for the prevention or dispersal of B. pseudomallei biofilm.},
}
@article {pmid30855125,
year = {2019},
author = {Aldrich, A and Kuss, MA and Duan, B and Kielian, T},
title = {3D Bioprinted Scaffolds Containing Viable Macrophages and Antibiotics Promote Clearance of Staphylococcus aureus Craniotomy-Associated Biofilm Infection.},
journal = {ACS applied materials &amp; interfaces},
volume = {11},
number = {13},
pages = {12298-12307},
doi = {10.1021/acsami.9b00264},
pmid = {30855125},
issn = {1944-8252},
abstract = {Craniotomy involves the removal of a skull fragment to access the brain, such as during tumor or epilepsy surgery, which is immediately replaced intraoperatively. The infection incidence after craniotomy ranges from 0.8 to 3%, with approximately half caused by Staphylococcus aureus (S. aureus). To mitigate infectious complications following craniotomy, we engineered a three-dimensional (3D) bioprinted bone scaffold to harness the potent antibacterial activity of macrophages (MΦs) together with antibiotics using a mouse S. aureus craniotomy-associated biofilm model that establishes a persistent infection on the bone flap, subcutaneous galea, and brain. The 3D scaffold contained rifampin and daptomycin printed in a composite slurry, with viable MΦs incorporated into a hydrogel-based bioink, which was assessed for both the treatment and prevention of craniotomy-associated infections in the mouse model. For the treatment paradigm, the bone flap was removed at day 7 post infection after a mature biofilm had formed and was replaced with a 3D printed antibiotic scaffold, with or without MΦ incorporation. Bacterial burdens in the galea and brain were reduced by at least 100-fold at early time points, which was potentiated by bioprinting viable MΦs into the 3D antibiotic scaffold. We also examined a prevention paradigm, where the scaffolds were placed at the time of surgery and challenged with S. aureus one day later at the surgical site. Interestingly, unlike the treatment paradigm, the incorporation of viable MΦs into the 3D antibiotic scaffold did not enhance bacterial clearance compared to that of antibiotic alone. With further refinement, our 3D bioprinted scaffold represents a potential treatment modality, as it delivers therapeutic antibiotic levels more rapidly than systemic administration, based on its proximity to the infection site. In addition, the incorporation of viable MΦs into the 3D scaffold is an important advance, which demonstrated an improved therapeutic benefit for the treatment of established biofilms that represent the most clinically challenging scenario.},
}
@article {pmid30853939,
year = {2019},
author = {Hussain, A and Alajmi, MF and Khan, MA and Pervez, SA and Ahmed, F and Amir, S and Husain, FM and Khan, MS and Shaik, GM and Hassan, I and Khan, RA and Rehman, MT},
title = {Biosynthesized Silver Nanoparticle (AgNP) From Pandanus odorifer Leaf Extract Exhibits Anti-metastasis and Anti-biofilm Potentials.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {8},
doi = {10.3389/fmicb.2019.00008},
pmid = {30853939},
issn = {1664-302X},
abstract = {Cancer and the associated secondary bacterial infections are leading cause of mortality, due to the paucity of effective drugs. Here, we have synthesized silver nanoparticles (AgNPs) from organic resource and confirmed their anti-cancer and anti-microbial potentials. Microwave irradiation method was employed to synthesize AgNPs using Pandanus odorifer leaf extract. Anti-cancer potential of AgNPs was evaluated by scratch assay on the monolayer of rat basophilic leukemia (RBL) cells, indicating that the synthesized AgNPs inhibit the migration of RBL cells. The synthesized AgNPs showed MIC value of 4-16 μg/mL against both Gram +ve and Gram -ve bacterial strains, exhibiting the anti-microbial potential. Biofilm inhibition was recorded at sub-MIC values against Gram +ve and Gram -ve bacterial strains. Violacein and alginate productions were reduced by 89.6 and 75.6%, respectively at 4 and 8 μg/mL of AgNPs, suggesting anti-quorum sensing activity. Exopolysaccharide production was decreased by 61-79 and 84% for Gram -ve and Gram +ve pathogens respectively. Flagellar driven swarming mobility was also reduced significantly. Furthermore, In vivo study confirmed their tolerability in mice, indicating their clinical perspective. Collective, we claim that the synthesized AgNPs have anti-metastasis as well as anti-microbial activities. Hence, this can be further tested for therapeutic options to treat cancer and secondary bacterial infections.},
}
@article {pmid30853830,
year = {2019},
author = {Novotny, LA and Brockman, KL and Mokrzan, EM and Jurcisek, JA and Bakaletz, LO},
title = {Biofilm biology and vaccine strategies for otitis media due to nontypeable Haemophilus influenzae.},
journal = {Journal of pediatric infectious diseases},
volume = {14},
number = {2},
pages = {69-77},
doi = {10.1055/s-0038-1660818},
pmid = {30853830},
issn = {1305-7707},
support = {R01 DC003915/DC/NIDCD NIH HHS/United States ; R01 DC011818/DC/NIDCD NIH HHS/United States ; R01 DC015688/DC/NIDCD NIH HHS/United States ; },
abstract = {Otitis media (OM) is one of the most common diseases of childhood, and nontypeable Haemophilus influenzae (NTHI) is the predominant causative agent of chronic and recurrent OM, as well as OM for which treatment has failed. Moreover, NTHI is now as important a causative agent of acute OM as the pneumococcus. NTHI colonizes the human nasopharynx asymptomatically. However, upon perturbation of the innate and physical defenses of the airway by upper respiratory tract viral infection, NTHI can replicate, ascend the Eustachian tube, gain access to the normally sterile middle ear space, and cause disease. Bacterial biofilms within the middle ear, including those formed by NTHI, contribute to the chronic and recurrent nature of this disease. These multicomponent structures are highly resistant to clearance by host defenses and elimination by traditional antimicrobial therapies. Herein, we review several strategies utilized by NTHI in order to persist within the human host and interventions currently under investigation to prevent and/or resolve NTHI-induced diseases of the middle ear and uppermost airway.},
}
@article {pmid30852214,
year = {2019},
author = {Meng, Y and Sheng, B and Meng, F},
title = {Changes in nitrogen removal and microbiota of anammox biofilm reactors under tetracycline stress at environmentally and industrially relevant concentrations.},
journal = {The Science of the total environment},
volume = {668},
number = {},
pages = {379-388},
doi = {10.1016/j.scitotenv.2019.02.389},
pmid = {30852214},
issn = {1879-1026},
mesh = {Biofilms/*drug effects/growth &amp; development ; Denitrification/*drug effects ; Nitrogen/*analysis ; Tetracycline/toxicity ; Waste Disposal, Fluid/*methods ; Waste Water ; Water Pollutants, Chemical/toxicity ; },
abstract = {Anammox-related processes are often applied for the wastewater treatment which contains both ammonium and antibiotics. Herein, the long-term effects of tetracycline (TC), at environmentally and industrially relevant concentrations, on the performance, anammox activity and microbial community of anammox reactors were investigated for 518 days. The control reactor (without TC exposure) was stable for nitrogen removal during the long-term operation (a nitrogen removal rate of 0.56 ± 0.05 kg-N·m-3·d-1). In the TC-added reactor, the nitrogen removal efficiency increased slightly at low TC levels (1-100 μg/L), whereas poor anammox performance occurred at high TC concentration (1000 μg/L). Furthermore, the concentrations of extracellular polymeric substances (EPS) were much higher at 10 μg/L than those in the control reactor (P < 0.01), whereas rapidly decreased at 1000 μg-TC/L. Furthermore, the reactor performance was highly consistent with the variations of the heme c contents. Consistently, exposure to TC changed the abundance of anammox bacteria, e.g., an increase in Candidatus Jettenia abundance occurred from 2.20 ± 0.97% (0-10 μg/L) to 12.13 ± 1.66% (100 μg/L). Similarly, the genus Denitratisoma, the most predominant denitrification bacteria, also had a higher abundance at a TC concentration of 100 μg/L (15.60 ± 6.42%) than other TC concentrations (5.40 ± 2.50% and 7.65 ± 0.55% at concentrations of 10 and 1000 μg/L, respectively). The results can explain why the exposure of anammox bacteria to a lower TC concentration (100 μg/L) resulted in a better nitrogen removal rate. In contrast, exposure to a high TC level (1000 μg/L) led to a decline in the abundance of anammox bacteria and denitrifiers (1.53 ± 0.64% and 8.18 ± 0.63%, respectively) but an increased abundance in the nitrifier population (8.07 ± 1.21%; P < 0.01). Therefore, this study can aid in the design and operation of anammox-based processes treating sewage and industrial wastewater.},
}
@article {pmid30851643,
year = {2019},
author = {Skowron, K and Wiktorczyk, N and Grudlewska, K and Kwiecińska-Piróg, J and Wałecka-Zacharska, E and Paluszak, Z and Gospodarek-Komkowska, E},
title = {Drug-susceptibility, biofilm-forming ability and biofilm survival on stainless steel of Listeria spp. strains isolated from cheese.},
journal = {International journal of food microbiology},
volume = {296},
number = {},
pages = {75-82},
doi = {10.1016/j.ijfoodmicro.2019.02.021},
pmid = {30851643},
issn = {1879-3460},
abstract = {The aim of the study was to analyze the contamination of mold cheese (Brie, Camembert, Gorgonzola, Munster and Roquefort) with Listeria spp. and assessment of culturable cells number recovered from the biofilm formed on the surface of stainless steel by obtained strains. Identified isolates (MALDI TOF MS technique) were subjected to susceptibility testing (disk-diffusion method) and their genetic similarity (PFGE method), ability to form biofilm (quantitative method), biofilm dry weight, and biofilm survival on stainless steel were evaluated. Out of 250 samples of cheese 26 (10.4%) were Listeria spp. positive, including 15 isolates (6.0% of samples) of L. monocytogenes, 7 isolates of L. innocua (2.8% of samples) and 4 isolates of L. welshimeri species (1.6% of samples). Of the 26 isolates tested, 22 strains were genetically different. It was shown that L. innocua and L. welshimeri strains were sensitive to all antibiotics tested, while two (16.7%) L. monocytogenes strains were resistant to penicillin and one (8.3%) to erythromycin. L. monocytogenes formed biofilm most intensively on stainless steel, while L. welshimeri the least effectively. The median of bacteria number recovered from the biofilm for L. monocytogenes was 6.81 log CFU × cm-2, for L. innocua - 5.63 log CFU × cm-2, and for L. welshimeri - 4.93 log CFU × cm-2. The survival in the biofilm of Listeria spp. strains decreased along with the increase in a storage temperature of steel coupons. The longest survival time was reported at 4 °C, i.e. 47.58-124.41 days, with an elimination rate of 0.06-0.13 log CFU × day-1. Collectively, L. monocytogenes is the most prevalent species of Listeria genus in the mold cheese. The ability of L. monocytogenes strains to form biofilm on stainless steel and survive in the food processing environment increases chance of the secondary contamination of food posing risk to the consumer health.},
}
@article {pmid30851361,
year = {2019},
author = {Calvillo-Medina, RP and Reyes-Grajeda, JP and Barba-Escoto, L and Bautista-Hernandez, LA and Campos-Guillén, J and Jones, GH and Bautista-de Lucio, VM},
title = {Proteome analysis of biofilm produced by a Fusarium falciforme keratitis infectious agent.},
journal = {Microbial pathogenesis},
volume = {130},
number = {},
pages = {232-241},
doi = {10.1016/j.micpath.2019.03.001},
pmid = {30851361},
issn = {1096-1208},
abstract = {Biofilms are structures that confer adaptive ability to and facilitate the virulence of fungal pathogens. Certain multi-functional proteins have been shown to be involved in fungal pathogenesis and these proteins may also be implicated in biofilm formation. The aim of this study was to identify a fungal agent isolated from the human cornea, to analyze the ability of this organism to form biofilms in vitro and to investigate protein expression in this condition. The fungus was identified by phylogenetic inference analysis. Biofilm formation and structure were evaluated by colorimetric methods and by optical and electron microscopy. We also resolved proteins obtained from biofilms and planktonic cultures by two-dimensional gel electrophoresis and identified those proteins by mass spectrometry. The fungus was identified as Fusarium falciforme. Colorimetric analysis and microscopy revealed that the highest level of biofilm formation was obtained at a concentration of 1 × 106 conidia/mL with 96 h of incubation at 28 °C. The biofilm architecture consisted of an extracellular matrix that embedded fungal filaments. We found nineteen proteins that were over-expressed in biofilms, as compared with planktonic cultures, and six proteins with unique expression in biofilms. Among the more abundant proteins identified were: transketolase, a putative antigen 1, enolase, phosphoglycerate kinase and ATP-citrate synthase. Some of these proteins are involved in basal metabolism, function as multi-functional proteins or have been described as potential virulence factors. We focused on the expression in biofilm of the enzyme, enolase, which was determined by real-time PCR. Our findings provide a perspective on the proteins associated with the formation of biofilms in vitro by an F. falciforme keratitis isolate.},
}
@article {pmid30850421,
year = {2019},
author = {Graf, AC and Leonard, A and Schäuble, M and Rieckmann, LM and Hoyer, J and Maaß, S and Lalk, M and Becher, D and Pané-Farré, J and Riedel, K},
title = {Virulence factors produced by Staphylococcus aureus biofilms have a moonlighting function contributing to biofilm integrity.},
journal = {Molecular &amp; cellular proteomics : MCP},
volume = {},
number = {},
pages = {},
doi = {10.1074/mcp.RA118.001120},
pmid = {30850421},
issn = {1535-9484},
abstract = {Staphylococcus aureus is the causative agent of various biofilm-associated infections in humans causing major healthcare problems worldwide. This type of infection is inherently difficult to treat due to a reduced metabolic activity of biofilm-embedded cells and the protective nature of a surrounding extracellular matrix (ECM). However, little is known about S. aureus biofilm physiology and in particular the proteinaceous composition of the ECM. Thus, we cultivated S. aureus biofilms in a flow system and comprehensively profiled intracellular and extracellular (ECM and flow-through (FT)) biofilm proteomes, as well as the extracellular metabolome in comparison to planktonic cultures. Our analyses revealed the expression of many pathogenicity factors within S. aureus biofilms as indicated by a high abundance of capsule biosynthesis proteins along with various secreted virulence factors, including hemolysins, leukotoxins, and lipases as a part of the ECM. The activity of ECM virulence factors was confirmed in a hemolysis assay and a Galleria mellonella pathogenicity model. In addition, we uncovered a so far unacknowledged moonlighting function of secreted virulence factors and ribosomal proteins trapped in the ECM: namely their contribution to biofilm integrity. Mechanistically, it was revealed that this stabilizing effect is mediated by the strong positive charge of alkaline virulence factors and ribosomal proteins in an acidic ECM environment, which is caused by the release of fermentation products like formate, lactate, and acetate as a consequence of oxygen limitation in biofilms. The strong positive charge of these proteins most likely mediates electrostatic interactions with anionic cell surface components, eDNA, and anionic metabolites. In consequence, this leads to strong cell aggregation and biofilm stabilization. Collectively, our study identified a new molecular mechanism during S. aureus biofilm formation and thus significantly widens the understanding of biofilm-associated S. aureus infections - an essential prerequisite for the development of novel antimicrobial therapies.},
}
@article {pmid30848779,
year = {2019},
author = {Osorio, JHM and Benettoni, P and Schmidt, M and Stryhanyuk, H and Schmitt-Jansen, M and Pinto, G and Pollio, A and Frunzo, L and Lens, PNL and Richnow, HH and Esposito, G and Musat, N},
title = {Investigation of architecture development and phosphate distribution in Chlorella biofilm by complementary microscopy techniques.},
journal = {FEMS microbiology ecology},
volume = {95},
number = {4},
pages = {},
doi = {10.1093/femsec/fiz029},
pmid = {30848779},
issn = {1574-6941},
abstract = {Microalgae biofilms may play an important role in the mitigation and prevention of eutrophication caused by domestic, agricultural and industrial wastewater effluents. Despite their potential, the biofilm development and role in nutrient removal are not well understood. Its clarification requires comprehensive studies of the complex three-dimensional architecture of the biofilm. In this study, we established a multimodal imaging approach to provide key information regarding architecture development and nutrient distribution in the biofilm of two green algae organisms: Chlorella pyrenoidosa and Chlorella vulgaris. Helium ion microscopy (HIM), scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were employed for i) elucidation of spatial arrangement, ii) elemental mapping and iii) 3D chemical imaging of the biofilm. The fine structure of the algal biofilm was resolved by HIM, the evidence of the accumulation of phosphate in hot spots was provided by SEM-EDX and the localization of phosphate oxides granules throughout the whole sample was clarified by ToF-SIMS. The reported results shed light on the phosphorus distribution during Chlorella's biofilm formation and highlight the potential of such correlative approach to solve fundamental question in algal biotechnology research.},
}
@article {pmid30848725,
year = {2019},
author = {Yan, J and Fei, C and Mao, S and Moreau, A and Wingreen, NS and Košmrlj, A and Stone, HA and Bassler, BL},
title = {Mechanical instability and interfacial energy drive biofilm morphogenesis.},
journal = {eLife},
volume = {8},
number = {},
pages = {},
doi = {10.7554/eLife.43920},
pmid = {30848725},
issn = {2050-084X},
support = {DMR-1420541//National Science Foundation/ ; Career Award at the Scientific Interface 1015763//Burroughs Wellcome Fund/ ; 2R37GM065859//National Institutes of Health/ ; MCB-1344191//National Science Foundation/ ; MCB-1713731//National Science Foundation/ ; R37 GM065859/GM/NIGMS NIH HHS/United States ; },
abstract = {Surface-attached bacterial communities called biofilms display a diversity of morphologies. Although structural and regulatory components required for biofilm formation are known, it is not understood how these essential constituents promote biofilm surface morphology. Here, using Vibrio cholerae as our model system, we combine mechanical measurements, theory and simulation, quantitative image analyses, surface energy characterizations, and mutagenesis to show that mechanical instabilities, including wrinkling and delamination, underlie the morphogenesis program of growing biofilms. We also identify interfacial energy as a key driving force for mechanomorphogenesis because it dictates the generation of new and the annihilation of existing interfaces. Finally, we discover feedback between mechanomorphogenesis and biofilm expansion, which shapes the overall biofilm contour. The morphogenesis principles that we discover in bacterial biofilms, which rely on mechanical instabilities and interfacial energies, should be generally applicable to morphogenesis processes in tissues in higher organisms.},
}
@article {pmid30847714,
year = {2019},
author = {Azman, AS and Mawang, CI and Khairat, JE and AbuBakar, S},
title = {Actinobacteria-a promising natural source of anti-biofilm agents.},
journal = {International microbiology : the official journal of the Spanish Society for Microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10123-019-00066-4},
pmid = {30847714},
issn = {1139-6709},
support = {GA004-2018//Yayasan Pahang/ ; },
abstract = {A biofilm is a community of microorganisms attached to a surface and embedded in a matrix of extracellular polymeric substances. Biofilms confer resistance towards conventional antibiotic treatments; thus, there is an urgent need for newer and more effective antimicrobial agents that can act against these biofilms. Due to this situation, various studies have been done to investigate the anti-biofilm effects of natural products including bioactive compounds extracted from microorganisms such as Actinobacteria. This review provides an insight into the anti-biofilm potential of Actinobacteria against various pathogenic bacteria, which hopefully provides useful information, guidance, and improvements for future antimicrobial studies. Nevertheless, further research on the anti-biofilm mechanisms and compound modifications to produce more potent anti-biofilm effects are required.},
}
@article {pmid30847656,
year = {2019},
author = {Sahar-Helft, S and Erez, A and Shay, B and Assad, R and Funk, B and Polak, D},
title = {Enhancing Er:YAG bactericidal effect against Enterococcus faecalis biofilm in vitro.},
journal = {Lasers in medical science},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10103-019-02763-y},
pmid = {30847656},
issn = {1435-604X},
}
@article {pmid30847541,
year = {2019},
author = {Xiros, C and Shahab, RL and Studer, MH},
title = {A cellulolytic fungal biofilm enhances the consolidated bioconversion of cellulose to short chain fatty acids by the rumen microbiome.},
journal = {Applied microbiology and biotechnology},
volume = {103},
number = {8},
pages = {3355-3365},
doi = {10.1007/s00253-019-09706-1},
pmid = {30847541},
issn = {1432-0614},
support = {407040_153868//Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (CH)/ ; KTI.2014.0116//Kommission für Technologie und Innovation/ ; },
abstract = {The ability of the multispecies biofilm membrane reactors (MBM reactors) to provide distinguished niches for aerobic and anaerobic microbes at the same time was used for the investigation of the consolidated bioprocessing of cellulose to short chain fatty acids (SCFAs). A consortium based consolidated bioprocess (CBP) was designed. The rumen microbiome was used as the converting microbial consortium, co-cultivated with selected individual aerobic fungi which formed a biofilm on the tubular membrane flushed with oxygen. The beneficial effect of the fungal biofilm on the process yields and productivities was attributed to the enhanced cellulolytic activities compared with those achieved by the rumen microbiome alone. At 30 °C, the MBM system with Trichoderma reesei biofilm reached a concentration 39% higher (7.3 g/L SCFAs), than the rumen microbiome alone (5.1 g/L) using 15 g/L crystalline cellulose as the substrate. Fermentation temperature was crucial especially for the composition of the short chain fatty acids produced. The temperature increase resulted in shorter fatty acids produced. While a mixture of acetic, propionic, butyric, and caproic acids was produced at 30 °C with Trichoderma reesei biofilm, butyric and caproic acids were not detected during the fermentations at 37.5 °C carried out with Coprinopsis cinerea as the biofilm forming fungus. Apart from the presence of the fungal biofilm, no parameter studied had a significant impact on the total yield of organic acids produced, which reached 0.47 g of total SCFAs per g of cellulose (at 30 °C and at pH 6, with rumen inoculum to total volume ratio equal to 0.372).},
}
@article {pmid30847048,
year = {2019},
author = {Lee, DH and Mai, HN and Thant, PP and Hong, SH and Kim, J and Jeong, SM and Lee, KW},
title = {Effects of different surface finishing protocols for zirconia on surface roughness and bacterial biofilm formation.},
journal = {The journal of advanced prosthodontics},
volume = {11},
number = {1},
pages = {41-47},
doi = {10.4047/jap.2019.11.1.41},
pmid = {30847048},
issn = {2005-7806},
abstract = {PURPOSE: Surface finishing of a zirconia restoration is essential after clinical adjustment. Herein, we investigated the effects of a surface finishing protocol for monolithic zirconia on final roughness and bacterial adherence.<br><br>MATERIALS AND METHODS: Forty-eight disk-shaped monolithic zirconia specimens were fabricated and divided into four groups (n = 12) based on initial surface treatment, finishing, and polishing protocols: diamond bur+polishing bur (DP group), diamond bur+stone grinding bur+polishing bur (DSP group), no diamond bur+polishing bur (NP group), and no diamond bur+stone grinding bur+polishing bur (NSP group). Initial and final surface roughness was measured with a profilometer, and shown using scanning electron microscope. Bacterial adhesion was evaluated by quantifying Streptococcus mutans in the biofilm. Kruskal-Wallis and Mann-Whitney U tests were used to compare results among groups, and two-way analysis of variance was used to evaluate the effects of grinding burs on final roughness (α=.05).<br><br>RESULTS: The DP group had the highest final Ra value, followed by the DSP, NP, and NSP groups. Use of the stone grinding bur as a coarse-finishing step significantly decreased final Ra values when a diamond bur was used (P<.001). Omission of the stone grinding bur increased biofilm formation on specimen surfaces. Combining a stone grinding bur with silicone polishing burs produced the smallest final biofilm values, regardless of the use of a diamond bur in initial surface treatment.<br><br>CONCLUSION: Coarse finishing of monolithic zirconia with a stone grinding bur significantly decreased final Ra values and bacterial biofilm formation when surfaces had been roughened by a diamond bur.},
}
@article {pmid30844070,
year = {2019},
author = {Fritz, B and Stavnsbjerg, C and Markvart, M and Damgaard, PB and Nielsen, SH and Bjørndal, L and Qvortrup, K and Bjarnsholt, T},
title = {Shotgun sequencing of clinical biofilm following scanning electron microscopy identifies bacterial community composition.},
journal = {Pathogens and disease},
volume = {77},
number = {1},
pages = {},
doi = {10.1093/femspd/ftz013},
pmid = {30844070},
issn = {2049-632X},
abstract = {Bacterial biofilm infections often involve aggregates of bacteria heterogeneously distributed throughout a tissue or on a surface (such as an implanted medical device). Identification of a biofilm infection requires direct visualization via microscopy, followed by characterization of the microbial community by culturing or sequencing-based approaches. A sample, therefore, must be divided prior to analysis, often leading to inconsistent results. We demonstrate a combined approach, using scanning electron microscopy and next-generation shotgun sequencing, to visually identify a biofilm and characterize the microbial community, without dividing the sample. A clinical sample recovered from a patient following a dental root-filling procedure was prepared and visualized by scanning electron microscopy. DNA was then extracted from the sample several years later and analyzed by shotgun sequencing. The method was subsequently validated on in vitro cultures of Pseudomonas aeruginosa biofilm. Between 19 and 21 different genera and species were identified in the clinical sample with an estimated relative abundance greater than 1% by two different estimation approaches. Only eight genera identified were not associated with endodontic infections. This provides a proof-of-concept for a dual, microscopy and sequencing-based approach to identify and characterize bacterial biofilms, which could also easily be implemented in other scientific fields.},
}
@article {pmid30843349,
year = {2019},
author = {Zetzmann, M and Bucur, FI and Crauwels, P and Borda, D and Nicolau, AI and Grigore-Gurgu, L and Seibold, GM and Riedel, CU},
title = {Characterization of the biofilm phenotype of a Listeria monocytogenes mutant deficient in agr peptide sensing.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e826},
doi = {10.1002/mbo3.826},
pmid = {30843349},
issn = {2045-8827},
support = {031B0268//Bundesministerium für Bildung und Forschung/ ; 15/2017//Executive Agency for Higher Education, Research, Development and Innovation Funding Romania/ ; },
abstract = {Listeria monocytogenes is a food-borne human pathogen and a serious concern in food production and preservation. Previous studies have shown that biofilm formation of L. monocytogenes and presence of extracellular DNA (eDNA) in the biofilm matrix varies with environmental conditions and may involve agr peptide sensing. Experiments in normal and diluted (hypoosmotic) complex media at different temperatures revealed reduced biofilm formation of L. monocytogenes EGD-e ΔagrD, a mutant deficient in agr peptide sensing, specifically in diluted Brain Heart Infusion at 25°C. This defect was not related to reduced sensitivity to DNase treatment suggesting sufficient levels of eDNA. Re-analysis of a previously published transcriptional profiling indicated that a total of 132 stress-related genes, that is 78.6% of the SigB-dependent stress regulon, are differentially expressed in the ΔagrD mutant. Additionally, a number of genes involved in flagellar motility and a large number of other surface proteins including internalins, peptidoglycan binding and cell wall modifying proteins showed agr-dependent gene expression. However, survival of the ΔagrD mutant in hypoosmotic conditions or following exposure to high hydrostatic pressure was comparable to the wild type. Also, flagellar motility and surface hydrophobicity were not affected. However, the ΔagrD mutant displayed a significantly reduced viability upon challenge with lysozyme. These results suggest that the biofilm phenotype of the ΔagrD mutant is not a consequence of reduced resistance to hypoosmotic or high pressure stress, motility or surface hydrophobicity. Instead, agr peptide sensing seems to be required for proper regulation of biosynthesis, structure and function of the cell envelope, adhesion to the substratum, and/or interaction of bacteria within a biofilm.},
}
@article {pmid30842579,
year = {2019},
author = {Goodwine, J and Gil, J and Doiron, A and Valdes, J and Solis, M and Higa, A and Davis, S and Sauer, K},
title = {Pyruvate-depleting conditions induce biofilm dispersion and enhance the efficacy of antibiotics in killing biofilms in vitro and in vivo.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {3763},
doi = {10.1038/s41598-019-40378-z},
pmid = {30842579},
issn = {2045-2322},
support = {1R56 AI127815-01A1//Division of Intramural Research, National Institute of Allergy and Infectious Diseases (Division of Intramural Research of the NIAID)/ ; 1R56 AI127815-01A1//Division of Intramural Research, National Institute of Allergy and Infectious Diseases (Division of Intramural Research of the NIAID)/ ; 1R56 AI127815-01A1//Division of Intramural Research, National Institute of Allergy and Infectious Diseases (Division of Intramural Research of the NIAID)/ ; 1R56 AI127815-01A1//Division of Intramural Research, National Institute of Allergy and Infectious Diseases (Division of Intramural Research of the NIAID)/ ; },
abstract = {The formation of biofilms is a developmental process initiated by planktonic cells transitioning to the surface, which comes full circle when cells disperse from the biofilm and transition to the planktonic mode of growth. Considering that pyruvate has been previously demonstrated to be required for the formation of P. aeruginosa biofilms, we asked whether pyruvate likewise contributes to the maintenance of the biofilm structure, with depletion of pyruvate resulting in dispersion. Here, we demonstrate that the enzymatic depletion of pyruvate coincided with the dispersion of established biofilms by S. aureus and laboratory and clinical P. aeruginosa isolates. The dispersion response was dependent on pyruvate fermentation pathway components but independent of proteins previously described to contribute to P. aeruginosa biofilm dispersion. Using porcine second-degree burn wounds infected with P. aeruginosa biofilm cells, we furthermore demonstrated that pyruvate depletion resulted in a reduction of biofilm biomass in vivo. Pyruvate-depleting conditions enhanced the efficacy of tobramycin killing of the resident wound biofilms by up to 5-logs. Our findings strongly suggest the management of pyruvate availability to be a promising strategy to combat biofilm-related infections by two principal pathogens associated with wound and cystic fibrosis lung infections.},
}
@article {pmid30842268,
year = {2019},
author = {Taylor, PK and Zhang, L and Mah, TF},
title = {Loss of the Two-Component System TctD-TctE in Pseudomonas aeruginosa Affects Biofilm Formation and Aminoglycoside Susceptibility in Response to Citric Acid.},
journal = {mSphere},
volume = {4},
number = {2},
pages = {},
doi = {10.1128/mSphere.00102-19},
pmid = {30842268},
issn = {2379-5042},
mesh = {Aminoglycosides/*pharmacology ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/drug effects/*growth &amp; development ; Citric Acid/*pharmacology ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Pseudomonas aeruginosa/*drug effects/*genetics ; Tobramycin/pharmacology ; },
abstract = {The two-component system TctD-TctE is important for regulating the uptake of tricarboxylic acids in Pseudomonas aeruginosa TctD-TctE accomplishes this through derepression of the gene opdH, which encodes a tricarboxylic acid-specific porin. Previous work from our lab revealed that TctD-TctE in P. aeruginosa also has a role in resistance to aminoglycoside antibiotics. The aim of this study was to further characterize the role of TctD-TctE in P. aeruginosa in the presence of citric acid. Here it was found that deletion of P. aeruginosa PA14 TctD-TctE (ΔtctED) resulted in a 4-fold decrease in the biofilm bactericidal concentrations of the aminoglycosides tobramycin and gentamicin when citric acid was present in nutrient media. Tobramycin accumulation assays demonstrated that deletion of TctD-TctE resulted in an increase in the amount of tobramycin retained in biofilm cells. The PA14 wild type responded to increasing concentrations of citric acid by producing less biofilm. In contrast, the amount of ΔtctED mutant biofilm formation remained constant or enhanced. Furthermore, the ΔtctED strain was incapable of growing on citric acid as a sole carbon source and was highly reduced in its ability to grow in the presence of citric acid even when an additional carbon source was available. Use of phenotypic and genetic microarrays found that this growth deficiency of the ΔtctED mutant is unique to citric acid and that multiple metabolic genes are dysregulated. This work demonstrates that TctD-TctE in P. aeruginosa has a role in biofilm development that is dependent on citric acid and that is separate from the previously characterized involvement in resistance to antibiotics.IMPORTANCE Nutrient availability is an important contributor to the ability of bacteria to establish successful infections in a host. Pseudomonas aeruginosa is an opportunistic pathogen in humans causing infections that are difficult to treat. In part, its success is attributable to a high degree of metabolic versatility. P. aeruginosa is able to sense and respond to varied and limited nutrient stress in the host environment. Two-component systems are important sensors-regulators of cellular responses to environmental stresses, such as those encountered in the host. This work demonstrates that the response by the two-component system TctD-TctE to the presence of citric acid has a role in biofilm formation, aminoglycoside susceptibility, and growth in P. aeruginosa.},
}
@article {pmid30840533,
year = {2019},
author = {Haesler, E and Swanson, T and Ousey, K and Carville, K},
title = {Clinical indicators of wound infection and biofilm: reaching international consensus.},
journal = {Journal of wound care},
volume = {28},
number = {Sup3b},
pages = {s4-s12},
doi = {10.12968/jowc.2019.28.Sup3b.S4},
pmid = {30840533},
issn = {0969-0700},
abstract = {OBJECTIVE: To achieve international consensus relating to clinical indicators for a chronic wound, wound infection and biofilm presence to inform the development of international clinical guidance for assessing and managing wound infection.<br><br>METHOD: An online Delphi consensus process of international key opinion leaders in infection was undertaken. A literature search underpinned the development of issue statements related to terminology, emerging topics and debate in the field of wound infection. Experts participated in three rounds of consensus voting, sharing their opinions and indicating their level of agreement with the issue statements. Votes were calculated using web-based software that implements a nominal group voting methodology previously published by Research and Development/University of California at Los Angeles.<br><br>RESULTS: A total of 14 experts took part in the development process. Consensus was reached on clinical indicators of wound chronicity, wound infection and biofilm presence. Agreement was also reached that the term 'critical colonisation' should no longer be used to refer to a stage in the wound infection continuum.<br><br>CONCLUSION: Outcomes from the consensus process were used to inform the development of international, evidence-informed guidance on the assessment and treatment of wound infection to promote improved outcomes for people with wounds.},
}
@article {pmid30838858,
year = {2019},
author = {Hu, MX and Li, JN and Guo, Q and Zhu, YQ and Niu, HM},
title = {Probiotics Biofilm-Integrated Electrospun Nanofiber Membranes: A New Starter Culture for Fermented Milk Production.},
journal = {Journal of agricultural and food chemistry},
volume = {67},
number = {11},
pages = {3198-3208},
doi = {10.1021/acs.jafc.8b05024},
pmid = {30838858},
issn = {1520-5118},
mesh = {Animals ; Biofilms ; Cattle ; Cultured Milk Products/analysis/microbiology ; Fermentation ; Food Microbiology/instrumentation/*methods ; Lactobacillus plantarum/growth &amp; development/metabolism ; Milk/*microbiology ; Nanofibers/chemistry ; Probiotics/*chemistry ; Streptococcus thermophilus/growth &amp; development/metabolism ; },
abstract = {Electrospun nanofiber membranes are widely investigated in the past few decades as candidates for tissue engineering, which can mimic natural extracellular matrix (ECM) and improve cell adhesion, proliferation, and expression on nanofiber membranes. However, the formation of bacterial biofilms on nanofiber membranes and application of the biofilm-integrated nanofiber membranes remain largely unknown. Here, electrospun cellulose acetate nanofiber membranes are first utilized as scaffold materials for Lactobacillus plantarum (L. plantarum) biofilm formation. Nanofiber membranes proved to be an excellent scaffold for bacteria biofilm with high stability, where biofilms were interlocked with nanofibers forming a cohesive structure. In comparison with planktonic bacteria, L. plantarum biofilms on nanofiber membranes show excellent gastrointestinal resistance. Instead of decreasing, the number of viable cells increased after 3 h digestion in vitro. The L. plantarum biofilm-integrated nanofiber membranes were used as reusable starter cultures for fermented milk production showing excellent fermentative ability and higher survival of L. plantarum during shelf life. The viable cells in fermented milk remained at 11 log CFU/g throughout the reusable batches, which is far above the required value of 7 log CFU/g in commercial products. In addition, the produced fermented milk possesses shorter fermentation time and higher survival of probiotics during shelf life. The results suggest electrospun nanofiber membranes are ideal scaffold materials for bacteria biofilms immobilization in biotechnology and fermentation engineering, which broaden the potential use of electrospun nanofiber membranes in microbiology and strengthen the application of biofilms in fermentation engineering.},
}
@article {pmid30838598,
year = {2019},
author = {Divaris, K and Shungin, D and Rodríguez-Cortés, A and Basta, PV and Roach, J and Cho, H and Wu, D and Ferreira Zandoná, AG and Ginnis, J and Ramamoorthy, S and Kinchen, JM and Kwintkiewicz, J and Butz, N and Ribeiro, AA and Azcarate-Peril, MA},
title = {The Supragingival Biofilm in Early Childhood Caries: Clinical and Laboratory Protocols and Bioinformatics Pipelines Supporting Metagenomics, Metatranscriptomics, and Metabolomics Studies of the Oral Microbiome.},
journal = {Methods in molecular biology (Clifton, N.J.)},
volume = {1922},
number = {},
pages = {525-548},
doi = {10.1007/978-1-4939-9012-2_40},
pmid = {30838598},
issn = {1940-6029},
support = {U01 DE025046/DE/NIDCR NIH HHS/United States ; },
abstract = {Early childhood caries (ECC) is a biofilm-mediated disease. Social, environmental, and behavioral determinants as well as innate susceptibility are major influences on its incidence; however, from a pathogenetic standpoint, the disease is defined and driven by oral dysbiosis. In other words, the disease occurs when the natural equilibrium between the host and its oral microbiome shifts toward states that promote demineralization at the biofilm-tooth surface interface. Thus, a comprehensive understanding of dental caries as a disease requires the characterization of both the composition and the function or metabolic activity of the supragingival biofilm according to well-defined clinical statuses. However, taxonomic and functional information of the supragingival biofilm is rarely available in clinical cohorts, and its collection presents unique challenges among very young children. This paper presents a protocol and pipelines available for the conduct of supragingival biofilm microbiome studies among children in the primary dentition, that has been designed in the context of a large-scale population-based genetic epidemiologic study of ECC. The protocol is being developed for the collection of two supragingival biofilm samples from the maxillary primary dentition, enabling downstream taxonomic (e.g., metagenomics) and functional (e.g., transcriptomics and metabolomics) analyses. The protocol is being implemented in the assembly of a pediatric precision medicine cohort comprising over 6000 participants to date, contributing social, environmental, behavioral, clinical, and biological data informing ECC and other oral health outcomes.},
}
@article {pmid30838426,
year = {2019},
author = {Khelissa, SO and Abdallah, M and Jama, C and Chihib, NE},
title = {Actively detached Pseudomonas aeruginosa biofilm cell susceptibility to benzalkonium chloride and associated resistance mechanism.},
journal = {Archives of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00203-019-01643-x},
pmid = {30838426},
issn = {1432-072X},
abstract = {The present work aimed at studying physiological properties of Pseudomonas aeruginosa cells actively detached from biofilm formed on stainless steel and comparing them with their planktonic counterparts as a function of growth temperature (20 °C and 37 °C). The susceptibility of P. aeruginosa cells to benzalkonium chloride (BAC) was studied. Furthermore, the effect of BAC on the cell membrane integrity and the role of the cell membrane fluidity in the cell-scale-resistance mechanism were investigated. Our results showed that actively detached biofilm cells were more susceptible to BAC treatment than planktonic ones. A greater leakage of intracellular potassium after BAC addition was observed in actively detached biofilm cells, which reflects their membrane vulnerability. The rise of the growth temperature from 20 to 37 °C increased the membrane rigidity of planktonic cells comparatively to their actively detached biofilm ones. Under experimental conditions developed in this work, our data highlighted that actively biofilm-detached and planktonic P. aeruginosa cells have distinguishable phenotypes.},
}
@article {pmid30837963,
year = {2019},
author = {Fonseca, BB and Silva, PLAPA and Silva, ACA and Dantas, NO and de Paula, AT and Olivieri, OCL and Beletti, ME and Rossi, DA and Goulart, LR},
title = {Nanocomposite of Ag-Doped ZnO and AgO Nanocrystals as a Preventive Measure to Control Biofilm Formation in Eggshell and Salmonella spp. Entry Into Eggs.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {217},
doi = {10.3389/fmicb.2019.00217},
pmid = {30837963},
issn = {1664-302X},
abstract = {Salmonella spp. is an important foodborne agent of salmonellosis, whose sources in humans often include products of avian origin. The control of this bacterium is difficult especially when Salmonella spp. is organized into biofilms. We hypothesized that the novel nanocomposites of ZnO nanocrystals doped with silver (Ag) and silver oxide (AgO) nanocrystals (ZnO:Ag-AgO) synthesized by the coprecipitation method could control or prevent the formation of Salmonella Enteritidis (SE) and Salmonella Heidelberg (SH) biofilm and its entry into turkey eggs. The diffraction characteristics of ZnO and AgO showed sizes of 28 and 30 nm, respectively. The Zn to Ag substitution into the ZnO crystalline structure was evidenced by the ionic radius of Ag+2 (1.26 Å), which is greater than Zn+2 (0.74 Å). For the SE analyses post-biofilm formation, the ZnO:Ag-AgO was not able to eliminate the biofilm, but the bacterial load was lower than that of the control group. Additionally, SE was able to infiltrate into the eggs and was found in both albumen and yolk. For the SH analyses applied onto the eggshells before biofilm formation, the ZnO:Ag-AgO treatment prevented biofilm formation, and although the bacterium infiltration into the eggs was observed in all treated groups, it was significantly smaller in ZnO:Ag-AgO pre-treated eggs, and SH could not reach the yolk. There was no difference in pore size between groups; therefore, the inhibition of biofilm formation and the prevention of bacterium entry into the egg were attributable to the use of ZnO:Ag-AgO, which was not influenced by the egg structure. Although the amount of Ag and Zn in the shell of the ZnO:Ag-AgO group was greater in relation to the control, this difference was not detected in the other egg components. In the search for new measures that are effective, safe and viable for controlling microorganisms in poultry farming, the application of a nanocomposite of Ag-doped ZnO and AgO nanocrystals appears as an alternative of great potential to prevent Salmonella sp biofilms in eggshells and other surfaces.},
}
@article {pmid30837355,
year = {2019},
author = {Ghosh, S and Qureshi, A and Purohit, H},
title = {D-Tryptophan governs biofilm formation rates and bacterial interaction in P. mendocina and S. aureus.},
journal = {Journal of biosciences},
volume = {44},
number = {1},
pages = {},
pmid = {30837355},
issn = {0973-7138},
abstract = {Biofilm genesis by Pseudomonasand Staphylococcus sp is associated with biofouling in natural settings. D-Tryptophan (D-Trp) inhibits bacterial biofilms and have been proposed for biofouling control applications. In this study, D-Trp significantly inhibited Pseudomonas mendocina and Staphylococcus aureuscell attachment (biofilm formation) rates on polystyrene96-well microtiter plates in comparison with L-Tryptophan (L-Trp) and mixtures of D-/L-Tryptophan (D-/L-Trp). Theinhibitory effect was greater on P. mendocina,where the rate of cell adherence was declined to 8.79105cells/h from8.09106cells/h (control) inP. mendocina.InS. aureusit was declined to 4.29107cells/h from 9.29107cells/h(control) at 1 mM concentration. It hindered the intracellular communication and adherence in both the strains, as con-firmed by SEM and real time PCR analysis. Addition of D-Trp to preformed biofilms also caused partial disassembly. Intraand interbacterial aggregation were decreased subsequently upon treatment with D-Trp. It repressed the genes involved incell-cell communication, which could be responsible for the diminished biofilm formation of the selected strains. HenceD-Tryptophan has proved to be an effective strategy to control biofilm and may support in the development of surfacecoating technologies.},
}
@article {pmid30837338,
year = {2019},
author = {Li, F and Cimdins, A and Rohde, M and Jänsch, L and Kaever, V and Nimtz, M and Römling, U},
title = {DncV Synthesizes Cyclic GMP-AMP and Regulates Biofilm Formation and Motility in Escherichia coli ECOR31.},
journal = {mBio},
volume = {10},
number = {2},
pages = {},
doi = {10.1128/mBio.02492-18},
pmid = {30837338},
issn = {2150-7511},
abstract = {Cyclic dinucleotides (cDNs) act as intracellular second messengers, modulating bacterial physiology to regulate the fundamental life style transition between motility and sessility commonly known as biofilm formation. Cyclic GMP-AMP (cGAMP), synthesized by the dinucleotide cyclase DncV, is a newly discovered cDN second messenger involved in virulence and chemotaxis in Vibrio cholerae O1 biovar El Tor. Here we report a novel role for horizontally transferred DncV in cGAMP production and regulation of biofilm formation and motility in the animal commensal strain Escherichia coli ECOR31. ECOR31 expresses a semiconstitutive temperature-independent rdar (red, dry, and rough) morphotype on Congo red agar plates characterized by the extracellular matrix components cellulose and curli fimbriae which requires activation by the major biofilm regulator CsgD and cyclic di-GMP signaling. In contrast, C-terminal His-tagged DncV negatively regulates the rdar biofilm morphotype and cell aggregation via downregulation of csgD mRNA steady-state level. Furthermore, DncV sequentially promotes and inhibits adhesion to the abiotic surface after 24 h and 48 h of growth, respectively. DncV also suppresses swimming and swarming motility posttranscriptional of the class 1 flagellum regulon gene flhD Purified DncV produced different cDNs, cyclic di-GMP, cyclic di-AMP, an unknown product(s), and the dominant species 3'3'-cGAMP. In vivo, only the 3'3'-cGAMP concentration was elevated upon short-term overexpression of dncV, making this work a first report on cGAMP production in E. coli Regulation of rdar biofilm formation and motility upon overexpression of untagged DncV in combination with three adjacent cotransferred gene products suggests a novel temperature-dependent cGAMP signaling module in E. coli ECOR31.IMPORTANCE The ability of bacteria to sense and respond to environmental signals is critical for survival. Bacteria use cyclic dinucleotides as second messengers to regulate a number of physiological processes, such as the fundamental life style transition between motility and sessility (biofilm formation). cGAMP, which is synthesized by a dinucleotide cyclase called DncV, is a newly discovered second messenger involved in virulence and chemotaxis in the Vibrio cholerae biovar El Tor causing the current 7th cholera pandemic. However, to what extent cGAMP exists and participates in physiological processes in other bacteria is still unknown. In this study, we found an elevated cGAMP level to possibly regulate biofilm formation and motility in the animal commensal E. coli strain ECOR31. Thus, we detected a novel role for cGAMP signaling in regulation of physiological processes other than those previously reported in proteobacterial species.},
}
@article {pmid30834698,
year = {2019},
author = {Nguyen, TV and Minrovic, BM and Melander, RJ and Melander, C},
title = {Identification of Anti-Mycobacterial Biofilm Agents Based on the 2-Aminoimidazole Scaffold.},
journal = {ChemMedChem},
volume = {},
number = {},
pages = {},
doi = {10.1002/cmdc.201900033},
pmid = {30834698},
issn = {1860-7187},
support = {R01 AI106733/AI/NIAID NIH HHS/United States ; AI106733//National Institutes of Health/ ; },
abstract = {Tuberculosis (TB) remains a significant global health problem for which new therapeutic options are sorely needed. The ability of the causative agent, Mycobacterium tuberculosis, to reside within host macrophages and form biofilm-like communities contributes to the persistent and drug-tolerant nature of the disease. Compounds that can prevent or reverse the biofilm-like phenotype have the potential to serve alongside TB antibiotics to overcome this tolerance, and decrease treatment duration. Using Mycobacterium smegmatis as a surrogate organism, we report the identification of two new 2-aminoimidazole compounds that inhibit and disperse mycobacterial biofilms, work synergistically with isoniazid and rifampicin to eradicate preformed M. smegmatis biofilms in vitro, are nontoxic toward Galleria mellonella, and exhibit stability in mouse plasma.},
}
@article {pmid30834278,
year = {2019},
author = {Bashir, A and Azeem, A and Stedman, Y and Hilton, AC},
title = {Pet Food Factory Isolates of Salmonella Serotypes Do Not Demonstrate Enhanced Biofilm Formation Compared to Serotype-Matched Clinical and Veterinary Isolates.},
journal = {BioMed research international},
volume = {2019},
number = {},
pages = {8569459},
doi = {10.1155/2019/8569459},
pmid = {30834278},
issn = {2314-6141},
abstract = {Environmentally persistent Salmonella in the pet food factory environment has been described, with biofilm formation suggested as a candidate mechanism contributing to their persistence. In this study the ability of a panel of Salmonella isolates from factory, clinical, and veterinary sources was investigated for their ability to form biofilms at 24 and 48 hours. The effect of nutrient availability and incubation time on biofilm formation was investigated using full strength and diluted 1/20 TSB media at 37°C, 25°C, 15°C, and 10°C. Results highlighted that all the Salmonella isolates were able to form biofilms in both nutrient conditions and this was highly correlated with temperature. At 25°C, biofilm formation was enhanced in diluted 1/20 TSB and increased incubation time (48h) (p= <0.001). However, this was not observed at 10°C, 15°C, or 37°C. None of the factory isolates demonstrated enhanced biofilm formation in comparison to serotype-matched isolates from veterinary and clinical sources. Salmonella enterica Senftenberg 775W was the strongest biofilm former at 15°C, 25°C, and 37°C in all the conditions tested (p=<0.05). Biofilm formation is an important mechanism of environmental persistence in the food manufacturing environment; however, there is no evidence of an enhanced biofilm-producing phenotype in factory persistent strains.},
}
@article {pmid30834226,
year = {2019},
author = {Balhaddad, AA and Melo, MAS and Gregory, RL},
title = {Inhibition of nicotine-induced Streptococcus mutans biofilm formation by salts solutions intended for mouthrinses.},
journal = {Restorative dentistry &amp; endodontics},
volume = {44},
number = {1},
pages = {e4},
doi = {10.5395/rde.2019.44.e4},
pmid = {30834226},
issn = {2234-7658},
abstract = {Objectives: Biofilm formation is critical to dental caries initiation and development. The aim of this study was to investigate the effects of nicotine exposure on Streptococcus mutans (S. mutans) biofilm formation concomitantly with the inhibitory effects of sodium chloride (NaCl), potassium chloride (KCl) and potassium iodide (KI) salts. This study examined bacterial growth with varying concentrations of NaCl, KCl, and KI salts and nicotine levels consistent with primary levels of nicotine exposure.<br><br>Materials and Methods: A preliminary screening experiment was performed to investigate the appropriate concentrations of NaCl, KCl, and KI to use with nicotine. With the data, a S. mutans biofilm growth assay was conducted using nicotine (0-32 mg/mL) in Tryptic Soy broth supplemented with 1% sucrose with and without 0.45 M of NaCl, 0.23 M of KCl, and 0.113 M of KI. The biofilm was stained with crystal violet dye and the absorbance measured to determine biofilm formation.<br><br>Results: The presence of 0.45 M of NaCl, 0.23 M of KCl, and 0.113 M of KI significantly inhibited (p < 0.05) nicotine-induced S. mutans biofilm formation by 52%, 79.7%, and 64.1%, respectively.<br><br>Conclusions: The results provide additional evidence regarding the biofilm-enhancing effects of nicotine and demonstrate the inhibitory influence of these salts in reducing the nicotine-induced biofilm formation. A short-term exposure to these salts may inhibit S. mutans biofilm formation.},
}
@article {pmid30833815,
year = {2019},
author = {Courrol, DDS and Lopes, CRB and Pereira, CBP and Franzolin, MR and Silva, FRO and Courrol, LC},
title = {Tryptophan Silver Nanoparticles Synthesized by Photoreduction Method: Characterization and Determination of Bactericidal and Anti-Biofilm Activities on Resistant and Susceptible Bacteria.},
journal = {International journal of tryptophan research : IJTR},
volume = {12},
number = {},
pages = {1178646919831677},
doi = {10.1177/1178646919831677},
pmid = {30833815},
issn = {1178-6469},
abstract = {The high rates of antibiotics use in hospitals have resulted in a condition where multidrug-resistant pathogens have become a severe threat to the human health worldwide. Therefore, there is an increasing necessity to identify new antimicrobial agents that can inhibit the multidrug-resistant bacteria and biofilm formation. In this study, antibacterial and anti-biofilm activities of tryptophan silver nanoparticles (TrpAgNP) were investigated. The TrpAgNPs were synthesized by photoreduction method, and the influence of irradiation time and concentration of reagents were analyzed. The nanoparticles were characterized by transmission electron microscopy, Zeta Potential and (UV)-absorption spectra. The antibacterial activity of TrpAgNPs was tested for antibiotic-resistant and susceptible pathogens, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Citrobacter freundii, Klebsiella pneumoniae, Salmonella typhimurium, and Pseudomonas aeruginosa, evaluating the influence of photoreduction parameters in bactericidal effect. The results have shown that TrpAgNPs solutions with lower tryptophan/silver nitrate (AgNO3) ratio and higher AgNO3 concentration have higher bactericidal action against bacteria with inhibition of ~100% in almost all studied bacterial strains. The antimicrobial activity of TrpAgNPs within biofilms generated under static conditions of antibiotic-resistant and susceptible strains of S. aureus, S. epidermidis, E. coli, K. pneumoniae, C. freundii, and P. aeruginosa was also investigated. The results showed that TrpAgNPs have an inhibitory effect against biofilm formation, exceeding 50% in the case of Gram-negative bacteria (E. coli, K. pneumoniae, C. freundii, and P. aeruginosa-54.8% to 98.8%). For Gram-positive species, an inhibition of biofilm formation of 68.7% to 72.2 % was observed for S. aureus and 20.0% to 40.2% for S. epidermidis.},
}
@article {pmid30833358,
year = {2019},
author = {Mihajlovic, J and Bechon, N and Ivanova, C and Chain, F and Almeida, A and Langella, P and Beloin, C and Ghigo, JM},
title = {A putative type V pilus contributes to Bacteroides thetaiotaomicron biofilm formation capacity.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00650-18},
pmid = {30833358},
issn = {1098-5530},
abstract = {Bacteroides thetaiotaomicron is a prominent anaerobe member of the healthy human gut microbiota. While the majority of functional studies on B. thetaiotaomicron addressed its impact on the immune system and the utilization of diet polysaccharide, B. thetaiotaomicron biofilm capacity and its contribution to intestinal colonization are still poorly characterized. We tested the natural adhesion of 34 B. thetaiotaomicron isolates and showed that, although biofilm capacity is widespread among B. thetaiotaomicron strains, this phenotype is masked or repressed in the widely used reference strain VPI 5482. Using transposon mutagenesis followed by a biofilm positive selection procedure we identified VPI 5482 mutants with increased biofilm capacity corresponding to an alteration in the C-terminal region of BT3147, encoded by the BT3148-BT3147 locus, which displays homology with mfa-like typeV pili found in many Bacteroidetes We showed that BT3147 is exposed on B. thetaiotaomicron surface and that BT3147-dependent adhesion also requires BT3148, suggesting that BT3148-BT3147 correspond to the anchor and stalk subunits of a new type V pilus involved in B. thetaiotaomicron adhesion. This study therefore introduces B. thetaiotaomicron as a model to study proteinaceous adhesins and biofilm-related phenotypes in this important intestinal symbiont.IMPORTANCE Although the gut anaerobe Bacteroides thetaiotaomicron is a prominent member of the healthy human gut microbiota, little is known on its capacity adhere to surfaces and form biofilms. Here, we identified that alteration of a surface exposed protein corresponding to a type of pili found in many Bacteroidetes increases B. thetaiotaomicron biofilm formation. This study lays the ground for establishing this bacterium as a model organism for in vitro and in vivo study of biofilm-related phenotypes in gut anaerobes.},
}
@article {pmid30833350,
year = {2019},
author = {Yannarell, SM and Grandchamp, GM and Chen, SY and Daniels, KE and Shank, EA},
title = {A dual-species biofilm with emergent mechanical and protective properties.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00670-18},
pmid = {30833350},
issn = {1098-5530},
abstract = {Many microbes coexist within biofilms, or multispecies communities of cells encased in an extracellular matrix. However, little is known about the microbe-microbe interactions relevant to creating these structures. In this study, we explored a striking dual-species biofilm between Bacillus subtilis and Pantoea agglomerans that exhibited characteristics that were not predictable from previous work examining monoculture biofilms. Coculture wrinkle formation required a P. agglomerans exopolysaccharide as well as the B. subtilis amyloid-like protein TasA. Unexpectedly, other B. subtilis matrix components essential for monoculture biofilm formation were not necessary for coculture wrinkling (e.g. the exopolysaccharide EPS, the hydrophobin BslA, and cell chaining). In addition, B. subtilis cell chaining prevented coculture wrinkling, even though chaining has previously been associated with more robust monoculture biofilms. We also observed that increasing the relative proportion of P. agglomerans (which forms completely featureless monoculture colonies) increased coculture wrinkling. Using microscopy and rheology, we observed that these two bacteria assemble into an organized layered structure that reflects the physical properties of both monocultures. This partitioning into distinct regions negatively affected the survival of P. agglomerans while also serving as a protective mechanism in the presence of antibiotic stress. Taken together, these data indicate that studying cocultures is a productive avenue to identify novel mechanisms that drive the formation of structured microbial communities.IMPORTANCE In the environment, many microbes form biofilms. However, the interspecies interactions underlying bacterial coexistence within these biofilms remain understudied. Here, we mimic environmentally relevant biofilms by studying a dual-species biofilm formed between Bacillus subtilis and Pantoea agglomerans and subjecting the coculture to chemical and physical stressors that it may experience in the natural world. We determined that both bacteria contribute structural elements to the coculture, which is reflected in its overall viscoelastic behavior. Existence within the coculture can be either beneficial or detrimental depending on the context. Many of the features and determinants of the coculture biofilm appear distinct from those identified in monoculture biofilm studies, highlighting the importance of characterizing multispecies consortia to understand naturally occurring bacterial interactions.},
}
@article {pmid30833012,
year = {2019},
author = {Kusuma Yulianto, HD and Rinastiti, M and Cune, MS and de Haan-Visser, W and Atema-Smit, J and Busscher, HJ and van der Mei, HC},
title = {Biofilm composition and composite degradation during intra-oral wear.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {35},
number = {5},
pages = {740-750},
doi = {10.1016/j.dental.2019.02.024},
pmid = {30833012},
issn = {1879-0097},
abstract = {OBJECTIVES: The oral environment limits the longevity of composite-restorations due to degradation caused by chewing, salivary and biofilm-produced enzymes and acids. This study investigates degradation of two resin-composites in relation with biofilm composition in vitro and in vivo.<br><br>METHODS: Surface-chemical-composition of two Bis-GMA/TEGDMA composites was compared using X-ray-Photoelectron-Spectroscopy from which the number ester-linkages was derived. Composite-degradation was assessed through water contact angles, yielding surface-exposure of filler-particles. Degradation in vitro was achieved by composite immersion in a lipase solution. In order to evaluate in vivo degradation, composite samples were worn in palatal devices by 15 volunteers for 30-days periods in absence and presence of manually-brushing with water. PCR-DGGE analysis was applied to determine biofilm composition on the samples, while in addition to water contact angles, degradation of worn composites was assessed through surface-roughness and micro-hardness measurements.<br><br>RESULTS: In vitro degradation by lipase exposure was highest for the high ester-linkage composite and virtually absent for the low ester-linkage composite. Filler-particle surface-exposure, surface-roughness and micro-hardness of both resin-composites increased during intra-oral wear, but filler-particle surface-exposure was affected most. However, based on increased filler-particle surface-exposure, the high ester-linkage composite degraded most in volunteers harvesting composite biofilms comprising Streptococcus mutans, a known esterase and lactic acid producer. This occurred especially in absence of brushing.<br><br>SIGNIFICANCE: Degradation during intra-oral wear of a low ester-linkage composite was smaller than of a high ester-linkage composite, amongst possible other differences between both composites. S. mutans herewith is not only a cariogenic, but also a composite-degradative member of the oral microbiome.},
}
@article {pmid30832841,
year = {2019},
author = {Ashrafi, B and Rashidipour, M and Marzban, A and Soroush, S and Azadpour, M and Delfani, S and Ramak, P},
title = {Mentha piperita essential oils loaded in a chitosan nanogel with inhibitory effect on biofilm formation against S. mutans on the dental surface.},
journal = {Carbohydrate polymers},
volume = {212},
number = {},
pages = {142-149},
doi = {10.1016/j.carbpol.2019.02.018},
pmid = {30832841},
issn = {1879-1344},
abstract = {Mentha piperita essential oils (MPEO) were loaded into chitosan nanogel to use as antibiofilm agent against Streptococcus mutans and to protect its dental plaque. Chitosan nanoparticles (CsNPs) were prepared by sol-gel method using linking bridge of tripolyphosphate (TPP). Physiological properties of MPEO-CNs were assessed by FTIR, SEM/EDX, DLS and zeta potential. Release kinetics, MIC and MBC were determined for MPEO-CNs. Expression of biofilm-associated genes including 8 genes: grfB, C and D, brpA, spaP, gbpB, relA and vicR was investigated at the presence of sub-MIC of MPEO-CNs. Most abundant bioactive compounds of MPEO were l-menthol (45.05%) and l-menthal (17.53%). SEM/EDX exhibited successful entrapment of MPEO into CsNPs followed by the changes in abundance of elemental peaks. A signal at 1737 cm-1 on chitosan spectrum was attributed to the carboxylic (CO) groups overlapped by MPEO incorporation. A new signal at 2361 cm-1 was assigned to electrostatic interactions of amine groups in chitosan with phosphoric units of TPP within the MPEO-chitosan. MPEO incorporation into porous nanogel decreased monodispersity of the nanoparticles and then raises z-average. Maximum release of MPEO was about 50% during 360 h in a hydroalcoholic solvent at ambient temperature. The adherence of bacterial cells showed high sensitivity to the nanoformulation of MPEO compared with unloaded chitosan-nanogel. Antibiofilm inhibition of S. mutans occurred in 50 and 400 μg/mL for MPEO-CNs and unloaded-nanogel, respectively. Among biofilm synthesis genes, gtfB, gtfC, gtfD were slightly affected by MPEO-CNs treatment, while gbpB, spaP, brpA, relA, and vicR genes underwent significant down-regulation in the presence of both unloaded-nanogel and MPEO-loaded-nanogel. This study demonstrated that the MPEO-CNs promised an efficient nanoformulation with the greatest inhibitory action against some glycosyltransferase genes (gtfB, C and D) as important enzymes involved in extracellular polymers. Finally, the results concluded that MPEO-CNs have a potential use as antibiofilm agent in toothpaste or mouth washing formulations.},
}
@article {pmid30831512,
year = {2019},
author = {Sonwani, RK and Swain, G and Giri, BS and Singh, RS and Rai, BN},
title = {A novel comparative study of modified carriers in moving bed biofilm reactor for the treatment of wastewater: Process optimization and kinetic study.},
journal = {Bioresource technology},
volume = {281},
number = {},
pages = {335-342},
doi = {10.1016/j.biortech.2019.02.121},
pmid = {30831512},
issn = {1873-2976},
abstract = {In this work, modified plastic carriers; polypropylene (PP), low-density polyethylene- polypropylene (LDPE-PP), and polyurethane foam-polypropylene (PUF-PP) were developed and used in moving bed bioreactor (MBBR) for the wastewater treatment containing naphthalene. To optimized the process parameters using response surface methodology (RSM), two numerical variables; pH (5.0-9.0) and hydraulic retention time (HRT) (1.0-5.0 day) along with the type of carriers (PP, LDPE-PP, and PUF-PP) were selected as a categorical factor. At 7.0 pH and 5 days HRT, maximum removal efficiencies were observed to be 72.4, 84.4, and 90.2% for MBBR packed with PP, LDPE-PP, and PUF-PP carriers, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis reveals catechol and 2-naphthol were observed as intermediate metabolites for naphthalene degradation. Modified Stover-Kincannon model was applied for biodegradation kinetic and constants were observed as Umax: 0.476, 0.666, and 0.769 g/L.day and KB: 0.565, 0.755, and 0.874 g/L.day for PP, LDPE-PP, PUF-PP, respectively.},
}
@article {pmid30831511,
year = {2019},
author = {Gao, JF and Liu, XH and Fan, XY and Dai, HH},
title = {Effects of triclosan on performance, microbial community and antibiotic resistance genes during partial denitrification in a sequencing moving bed biofilm reactor.},
journal = {Bioresource technology},
volume = {281},
number = {},
pages = {326-334},
doi = {10.1016/j.biortech.2019.02.112},
pmid = {30831511},
issn = {1873-2976},
abstract = {Effects of triclosan (TCS) on performance, microbial community and antibiotic resistance genes (ARGs) during partial denitrification (PD) were investigated in a sequencing moving bed biofilm reactor (SMBBR). TCS inhibited nitrite accumulation; inhibition effect was more obvious as TCS concentration increased from 1 to 5 mg/L, but it could recover. Extracellular polymeric substances contents increased with 1 mg/L TCS addition and decreased a lot at 5 mg/L TCS. Community structure in biofilm was different from that in floccular sludge, but it was similar at 5 mg/L TCS. Illumina sequencing showed that Pseudomonas, Aeromonas, Shewanella and Thauera became dominant genera. Abundance of nirS was stable and higher than that of narG and nosZ. High-throughput qPCR showed that mexF, acrA-02, fabK, etc. were screened at 5 mg/L TCS. IntI1 and tnpA-04 were abundant mobile genetic elements. The study furthers understanding of effects of TCS on PD, bacterial communities and ARGs in SMBBR.},
}
@article {pmid30831372,
year = {2019},
author = {Cui, X and Chen, C and Liu, Y and Zhou, D and Liu, M},
title = {Exogenous refractory protein enhances biofilm formation by altering the quorum sensing system: A potential hazard of soluble microbial proteins from WWTP effluent.},
journal = {The Science of the total environment},
volume = {667},
number = {},
pages = {384-389},
doi = {10.1016/j.scitotenv.2019.02.370},
pmid = {30831372},
issn = {1879-1026},
mesh = {Bacteria ; Bacterial Proteins/*analysis ; Biofilms ; Gene Expression Regulation, Bacterial ; *Quorum Sensing ; Waste Disposal, Fluid/*methods ; Waste Water/*microbiology ; Water Pollutants/*analysis ; },
abstract = {Soluble microbial refractory proteins are major components of effluent from wastewater treatment plants that utilize a biological wastewater treatment process. The remaining proteins could negatively affect downstream treatment processes by altering the bacterial quorum sensing system. In this work, we elaborated the effects of exogenous refractory protein on biofilm formation. The results showed a linear relationship between biofilm formation and experimental protein concentrations at the range typically found in effluent, 0-8.0 mg/L. Micro-observation revealed that the exogenous refractory protein stimulated extracellular polysaccharide secretion to promote biofilm maturation. Extracellular polysaccharides increased by ~200% with the addition of only 2.0 mg/L protein. In addition, exogenous refractory proteins altered the quorum sensing system gene expression and polysaccharide gene expression. This work found that exogenous protein accelerated biofilm formation by influencing the quorum sensing system, thus providing new insight into the potential harm of soluble microbial refractory products.},
}
@article {pmid30831325,
year = {2019},
author = {Rodríguez López, AL and Lee, MR and Ortiz, BJ and Gastfriend, BD and Whitehead, R and Lynn, DM and Palecek, SP},
title = {Preventing S. aureus biofilm formation on titanium surfaces by the release of antimicrobial β-peptides from polyelectrolyte multilayers.},
journal = {Acta biomaterialia},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.actbio.2019.02.047},
pmid = {30831325},
issn = {1878-7568},
abstract = {Staphylococcus aureus infections represent the major cause of titanium based-orthopaedic implant failure. Current treatments for S. aureus infections involve the systemic delivery of antibiotics and additional surgeries, increasing health-care costs and affecting patient's quality of life. As a step toward the development of new strategies that can prevent these infections, we build upon previous work demonstrating that the colonization of catheters by the fungal pathogen Candida albicans can be prevented by coating them with thin polymer multilayers composed of chitosan (CH) and hyaluronic acid (HA) designed to release a β-amino acid-based peptidomimetic of antimicrobial peptides (AMPs). We demonstrate here that this β-peptide is also potent against S. aureus (MBPC = 4 μg/mL) and characterize its selectivity toward S. aureus biofilms. We demonstrate further that β-peptide-containing CH/HA thin-films can be fabricated on the surfaces of rough planar titanium substrates in ways that allow mammalian cell attachment and permit the long-term release of β-peptide. β-Peptide loading on CH/HA thin-films was then adjusted to achieve release of β-peptide quantities that selectively prevent S. aureus biofilms on titanium substrates in vitro for up to 24 days and remained antimicrobial after being challenged sequentially five times with S. aureus inocula, while causing no significant MC3T3-E1 preosteoblast cytotoxicity compared to uncoated and film-coated controls lacking β-peptide. We conclude that these β-peptide-containing films offer a novel and promising localized delivery approach for preventing orthopaedic implant infections. The facile fabrication and loading of β-peptide-containing films reported here provides opportunities for coating other medical devices prone to biofilm-associated infections. STATEMENT OF SIGNIFICANCE: Titanium (Ti) and its alloys are used widely in orthopaedic devices due to their mechanical strength and long-term biocompatibility. However, these devices are susceptible to bacterial colonization and the subsequent formation of biofilms. Here we report a chitosan and hyaluronic acid polyelectrolyte multilayer-based approach for the localized delivery of helical, cationic, globally amphiphilic β-peptide mimetics of antimicrobial peptides to inhibit S. aureus colonization and biofilm formation. Our results reveal that controlled release of this β-peptide can selectively kill S. aureus cells without exhibiting toxicity toward MC3T3-E1 preosteoblast cells. Further development of this polymer-based coating could result in new strategies for preventing orthopaedic implant-related infections, improving outcomes of these titanium implants.},
}
@article {pmid30831229,
year = {2019},
author = {Hiller, CC and Lucca, V and Carvalho, D and Borsoi, A and Borges, KA and Furian, TQ and do Nascimento, VP},
title = {Influence of catecholamines on biofilm formation by Salmonella Enteritidis.},
journal = {Microbial pathogenesis},
volume = {130},
number = {},
pages = {54-58},
doi = {10.1016/j.micpath.2019.02.032},
pmid = {30831229},
issn = {1096-1208},
abstract = {Salmonella spp. are the main pathogens responsible for foodborne disease worldwide. Bacterial communities use the quorum sensing system to control biofilm formation. These systems function through the secretion of substances, called auto-inducers (AI), into the environment. AI-3 is structurally similar to epinephrine (EPI) and norepinephrine (NOR) -catecholamines secreted by eukaryotic cells to communicate with each other. In this context, this work aimed to evaluate the effect of EPI and NOR on biofilm formation by S. Enteritidis at 12 °C and 25 °C. Also, we detected the presence of the csgD, adrA, and fimA genes in these strains. Biofilm formation was investigated at two temperatures (12 °C and 25 °C) using a microtiter plate assay, under four different treatments (50 mM EPI, 100 mM EPI, 50 mM NOR; 100 mM NOR) and a control group. PCR was used to detect the virulence genes associated with biofilm production. A greater number of biofilm producer isolates were observed at 25 °C than at 12 °C, regardless of the treatment. The number of biofilms forming strains at 12 °C was significantly higher in the treatment with norepinephrine at 100 μM. The proportion of non-producer and biofilm producer strains at 25 °C did not differ significantly among the treatments. All strains presented the three genes (csgD, adrA, and fimA). The approach carried out in this work is a precursor in veterinary medicine, focusing on both public and poultry health, and evaluates the influence of catecholamines on the formation of biofilms with S. Enteritidis, an important pathogen with zoonotic potential. Norepinephrine seems to be more efficient at stimulating biofilm formation by S. Enteritidis strains at 12 °C. csgD, fimA, and adrA were detected in all strains.},
}
@article {pmid30830100,
year = {2019},
author = {Maev, IV and Bazikyan, EA and Lukina, GI and Zayratyants, OV and Chunikhin, AA},
title = {[Features of filiform papillary lesion of the tongue and its mucosal microflora biofilm in patients with gastroesophageal reflux disease].},
journal = {Arkhiv patologii},
volume = {81},
number = {1},
pages = {18-23},
doi = {10.17116/patol20198101118},
pmid = {30830100},
issn = {0004-1955},
abstract = {OBJECTIVE: To identify filiform papillary lesions, localization changes, and the composition of the microflora of the dorsal lingual surface in patients with gastroesophageal reflux disease (GERD).<br><br>MATERIAL AND METHODS: Dorsal lingual surface biopsy specimens were investigated in 7 patients with GERD (3 men, 4 women) and in 6 individuals without digestive diseases (3 men, 3 women). The diagnosis of GERD was based on a set of clinical data, daily pH-metry, EGDS, and the specialized GerdQ questionnaire. Scanning electron microscopy and fluorescence confocal microscopy were used.<br><br>RESULTS: Intact filiform lingual papillae had a complex structure and consisted of primary and secondary papillae. Foci of increased epithelial desquamation with partial or complete loss of secondary papillae were detected in patients with GERD. There was a microflora biofilm only on the epithelium of the secondary papillae in the intact areas and in the areas with preserved secondary papillae in patients with GERD. On the contrary, the foci of lesion and those with completely lost secondary papillae in GERD patients exhibited the microflora (more diverse in its morphological characteristics) on the surface of the epithelial cells of primary papillae, except for their cup-shaped hollows in the area of the lost secondary processes. These cup-shaped hollows preserved dense intercellular contacts of epithelial cells.<br><br>CONCLUSION: The lingual mucosal filiform papillae in GERD patients are characterized by the appearance of areas with partial or complete loss of secondary papillae and with increased desquamation of epithelial cells. There is microflora biofilm translocation to the primary papillae, except for their cup-shaped hollows (an area of the lost secondary papillae). Translocation of the microflora increased its morphological diversity.},
}
@article {pmid30828488,
year = {2019},
author = {Shang, F and Li, L and Yu, L and Ni, J and Chen, X and Xue, T},
title = {Effects of stigmata maydis on the methicillin resistant Staphylococus aureus biofilm formation.},
journal = {PeerJ},
volume = {7},
number = {},
pages = {e6461},
doi = {10.7717/peerj.6461},
pmid = {30828488},
issn = {2167-8359},
abstract = {Background: Mastitis is an inflammatory reaction of the mammary gland tissue, which causes huge losses to dairy farms throughout the world. Staphylococcus aureus is the most frequent agent associated with this disease. Staphylococcus aureus isolates, which have the ability to form biofilms, usually lead to chronic mastitis in dairy cows. Moreover, methicillin resistance of the bacteria further complicates the treatment of this disease. Stigmata maydis (corn silk), a traditional Chinese medicine, possess many biological activities.<br><br>Methods: In this study, we performed antibacterial activity assays, biofilm formation assays and real-time reverse transcription PCR experiments to investigate the effect of stigmata maydis (corn silk) on biofilm formation and vancomycin susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from dairy cows with mastitis.<br><br>Results: In this study, the aqueous extracts of stigmata maydis inhibited the biofilm formation ability of MRSA strains and increased the vancomycin susceptibility of the strains under biofilm-cultured conditions.<br><br>Conclusion: This study proves that the aqueous extracts of stigmata maydis inhibit the biofilm formation ability of MRSA strains and increase the vancomycin susceptibility of the MRSA strains under biofilm-cultured conditions.},
}
@article {pmid30827805,
year = {2019},
author = {Beganovic, M and Luther, MK and Daffinee, KE and LaPlante, KL},
title = {Biofilm prevention concentrations (BPC) of minocycline compared to polymyxin B, meropenem, and amikacin against Acinetobacter baumannii.},
journal = {Diagnostic microbiology and infectious disease},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.diagmicrobio.2019.01.016},
pmid = {30827805},
issn = {1879-0070},
abstract = {Infections caused by Acinetobacter baumannii are difficult to treat as they are often multidrug resistant (MDR) and frequently form biofilms. We investigated the activities of minocycline, polymyxin B, meropenem, and amikacin against diverse Acinetobacter baumannii strains with biofilm formation classified as weak versus moderate/strong. At clinically achievable concentrations, minocycline prevented biofilm formation for 96% of isolates versus 54% for polymyxin B, 29% for meropenem and 29% for amikacin. Minocycline and polymyxin B demonstrated highest in vitro activity against A. baumannii and prevented biofilm formation for a majority of isolates.},
}
@article {pmid30826880,
year = {2019},
author = {Hamilos, DL},
title = {Biofilm Formations in Pediatric Respiratory Tract Infection Part 2: Mucosal Biofilm Formation by Respiratory Pathogens and Current and Future Therapeutic Strategies to Inhibit Biofilm Formation or Eradicate Established Biofilm.},
journal = {Current infectious disease reports},
volume = {21},
number = {2},
pages = {8},
doi = {10.1007/s11908-019-0657-x},
pmid = {30826880},
issn = {1523-3847},
abstract = {PURPOSE OF REVIEW: The purpose of this review is to discuss the unique pathways of biofilm formation utilized by respiratory pathogens and current and future therapeutic strategies to inhibit biofilm formation or eradicate established biofilm in the context of these pathogens. Both nonselective and selective strategies for inhibiting biofilm formation or disrupting established biofilm are discussed.<br><br>RECENT FINDINGS: Numerous strategies are being actively pursued to inhibit biofilm formation or eradicate established biofilm in respiratory pathogens. These can be broadly categorized by the stage of biofilm formation (adhesion, extracellular polysaccharide synthesis or structure, EPS, and matrix degradation) that they target and by their selectivity or lack thereof for specific biofilm pathogens. Nonselective inhibitors of adhesion include N-acetylcysteine and artificial surfactants and biosurfactants. Selective inhibitors of adhesion include mannosides that target host-EPS interactions, EPS-targeted antibodies, and other inhibitors of bacterial adhesion. Nonselective inhibitors of EPS synthesis and structure include cyclic di-GMP and cyclic di-AMP-through disruption of glucan-producing exoenzymes. Selective inhibitors of EPS synthesis and structure include antibodies that target proteins essential for biofilm structure (such as DNABII proteins and type IV pilin protein in NTHi) or antibodies that target critical molecules in biofilm formation (such as DNA adenine methyltransferase in Streptococcus pneumoniae). Nonselective agents for EPS or biofilm matrix degradation include peptidoglycan hydrolases that enzymatically degrade bacterial cell wall peptidoglycan and DNase, which degrades extracellular DNA from neutrophils and microorganism-derived DNA. Selective agents for EPS or biofilm matrix degradation include exopolysaccharide-degrading enzymes, such as glycoside hydrolases active against Staphylococcus aureus or exopolysaccharide-degrading enzymes that target Psl and Pel from Pseudomonas aeruginosa. Current strategies toward inhibiting biofilm formation or disrupting established biofilm represent an exciting new approach toward treatment of chronic infectious diseases. Application of these strategies toward treatment of pediatric respiratory tract infections also offers promise of a better understanding of the significance of mucosal biofilm in the pathogenesis of these conditions.},
}
@article {pmid30826631,
year = {2019},
author = {Perez, AP and Perez, N and Lozano, CMS and Altube, MJ and de Farias, MA and Portugal, RV and Buzzola, F and Morilla, MJ and Romero, EL},
title = {The anti MRSA biofilm activity of Thymus vulgaris essential oil in nanovesicles.},
journal = {Phytomedicine : international journal of phytotherapy and phytopharmacology},
volume = {57},
number = {},
pages = {339-351},
doi = {10.1016/j.phymed.2018.12.025},
pmid = {30826631},
issn = {1618-095X},
abstract = {BACKGROUND: Thymus vulgaris essential oil (T) could be an alternative to classical antibiotics against bacterial biofilms, which show increased tolerance to antibiotics and host defence systems and contribute to the persistence of chronic bacterial infections.<br><br>HYPOTHESIS: A nanovesicular formulation of T may chemically protect the structure and relative composition of its multiple components, potentially improving its antibacterial and antibiofilm activity.<br><br>STUDY DESIGN: We prepared and structurally characterized T in two types of nanovesicles: nanoliposomes (L80-T) made of Soybean phosphatidylcholine (SPC) and Polysorbate 80 (P80) [SPC:P80:T 1:0.75:0.3 w:w], and nanoarchaeosomes (A80-T) made of SPC, P80 and total polar archaeolipids (TPA) extracted from archaebacteria Halorubrum tebenquichense [SPC:TPA:P80:T 0.5:0.50.75:0.7 w:w]. We determined the macrophage cytotoxicity and the antibacterial activity against Staphylococcus aureus ATCC 25,923 and four MRSA clinical strains.<br><br>RESULTS: L80-T (Z potential -4.1 ± 0.6 mV, ∼ 115 nm, ∼ 22 mg/ml T) and A80-T (Z potential -6.6 ± 1.5 mV, ∼ 130 nm, ∼ 42 mg/ml T) were colloidally and chemically stable, maintaining size, PDI, Z potential and T concentration for at least 90 days. While MIC90 of L80-T was > 4 mg/ml T, MIC90 of A80-T was 2 mg/ml T for all S. aureus strains. The antibiofilm formation activity was maximal for A80-T, while L80-T did not inhibit biofilm formation compared to untreated control. A80-T significantly decreased the biomass of preformed biofilms of S. aureus ATCC 25,923 strain and of 3 of the 4 clinical MRSA isolates at 4 mg/ml T. It was found that the viability of J774A.1 macrophages was decreased significantly upon 24 h incubation with A80-T, L80-T and T emulsion at 0.4 mg/ml T. These results show that from 0.4 mg/ml T, a value lower than MIC90 and the one displaying antibiofilm activity, with independence of its formulation, T significantly decreased the macrophages viability.<br><br>CONCLUSION: Overall, because of its lower MIC90 against planktonic bacteria, higher antibiofilm formation capacity and stability during storage, A80-T resulted better antibacterial agent than T emulsion and L80-T. These results open new avenues to explode the A80-T antimicrobial intracellular activity.},
}
@article {pmid30826440,
year = {2019},
author = {Rajamani, S and Sandy, R and Kota, K and Lundh, L and Gomba, G and Recabo, K and Duplantier, A and Panchal, RG},
title = {Robust biofilm assay for quantification and high throughput screening applications.},
journal = {Journal of microbiological methods},
volume = {159},
number = {},
pages = {179-185},
doi = {10.1016/j.mimet.2019.02.018},
pmid = {30826440},
issn = {1872-8359},
abstract = {Bacterial biofilms are populations of bacteria within a self-produced adherent extracellular matrix that are notoriously resistant to treatment. Existing methods for biofilm quantification are often limited in their dynamic range of detection (signal-to-background), throughput, and require modifications to the protocol depending on the bacterial species. To address these limitations, a broad utility, high-throughput (HTP) method was required. Using a fluorescent dye, FM1-43, we stained the biofilm, followed by solvent extraction and quantitation of biofilm employing a fluorescent plate reader. Utilizing eight different bacterial pathogens, we demonstrate that this method is widely applicable for biofilm quantification. Depending on the species, this biofilm assay offered a large dynamic range of 8-146 fold change compared to 2-22 fold for crystal violet staining under similar conditions. In addition to routine biofilm quantification using this new assay, as a proof-of-concept, 1200 compounds were screened against two different bacterial species to identify biofilm inhibitors. In our HTP screens we successfully identified compounds rifabutin and ethavarine as potential biofilm inhibitors of Burkholderia pseudomallei Bp82 and Acinetobacter baumannii biofilm production respectively. This newly validated biofilm assay is robust and can be readily adapted for antibiofilm screening campaigns and can supplant other less sensitive and low throughput methods.},
}
@article {pmid30825823,
year = {2019},
author = {Lv, PL and Shi, LD and Wang, Z and Rittmann, B and Zhao, HP},
title = {Methane oxidation coupled to perchlorate reduction in a membrane biofilm batch reactor.},
journal = {The Science of the total environment},
volume = {667},
number = {},
pages = {9-15},
doi = {10.1016/j.scitotenv.2019.02.330},
pmid = {30825823},
issn = {1879-1026},
mesh = {*Biofilms ; *Bioreactors ; High-Throughput Nucleotide Sequencing ; Membranes, Artificial ; Methane/*metabolism ; Methanosarcina/*physiology ; Oxidation-Reduction ; Perchlorates/*metabolism ; Phylogeny ; RNA, Archaeal/analysis ; RNA, Ribosomal, 16S/analysis ; Real-Time Polymerase Chain Reaction ; *Waste Disposal, Fluid ; },
abstract = {A specially designed CH4-based membrane biofilm batch reactor (MBBR) was applied to investigate anaerobic methane oxidation coupled to perchlorate reduction (AnMO-PR). The 0.21 mM ClO4- added in the first stage of operation was completely reduced in 28 days, 0.40 mM ClO4- was reduced within 23 days in stage 2, and 0.56 mM of ClO4- was reduced within 30 days in stage 3. Although some chlorate (ClO3-) accumulated, the recovery of Cl- was over 92%. Illumina sequencing of the 16S rRNA gene documented that the bacterial community was mainly composed by perchlorate-reducing bacteria (PRB), methanotrophic bacteria, and archaea. Real-time quantitative PCR showed the archaeal 16S rRNA and mcrA genes increased as more ClO4- was reduced, and the predominant archaea belonged to Methanosarcina mazei, which is related to ANME-3, an archaeon able to perform reverse methanogenesis. Several pieces of evidence support that ClO4- reduction by the MBBR biofilm occurred via a synergism between Methanosarcina and PRB: Methanosarcina oxidized methane through reverse methanogesis and provided electron donor for PRB to reduce ClO4-. Because methanotrophs were present, we cannot rule out that they also were involved in AnMO-PR if they received O2 generated by disproportionation of ClO2- from the PRB.},
}
@article {pmid30825658,
year = {2019},
author = {Huerta-Miranda, GA and Arroyo-Escoto, AI and Burgos, X and Juárez, K and Miranda-Hernández, M},
title = {Influence of the major pilA transcriptional regulator in electrochemical responses of Geobacter sulfureducens PilR-deficient mutant biofilm formed on FTO electrodes.},
journal = {Bioelectrochemistry (Amsterdam, Netherlands)},
volume = {127},
number = {},
pages = {145-153},
doi = {10.1016/j.bioelechem.2019.02.006},
pmid = {30825658},
issn = {1878-562X},
mesh = {Bacterial Proteins/*genetics ; Bioelectric Energy Sources/microbiology ; *Biofilms/growth &amp; development ; Electric Conductivity ; Electrodes ; Electron Transport ; Fimbriae, Bacterial/*genetics ; Fluorine/chemistry ; Gene Deletion ; *Gene Expression Regulation, Bacterial ; Geobacter/*genetics/physiology ; Oxidation-Reduction ; Tin Compounds/chemistry ; Transcription Factors/*genetics ; },
abstract = {Geobacter sulfurreducens is a model organism for understanding the role of bacterial structures in extracellular electron transfer mechanism (EET). This kind of bacteria relies on different structures such as type IV pili and over 100 c-type cytochromes to perform EET towards soluble and insoluble electron acceptors, including electrodes. To our knowledge, this work is the first electrochemical study comparing a G. sulfurreducens PilR-deficient mutant and wild type biofilms developed on fluorine-doped tin oxide (FTO) electrodes. Open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), were used to evaluate the electroactive properties of biofilms grown without externally imposed potential. Parallel studies of Confocal Laser Scanning Microscopy (CLSM) correlated with the electrochemical results. PilR is a transcriptional regulator involved in the expression of a wide variety of genes, including pilA (pilus structural protein) relevant c-type cytochromes and some other genes involved in biofilm formation and EET processes. Our findings suggest that PilR-deficient mutant forms a thinner (CLSM analysis) and less conductive biofilm (EIS analysis) than wild type, exhibiting different and irreversible redox processes at the interface (CV analysis). Additionally, this work reinforces some of the remarkable features described in previous reports about this G. sulfurreducens mutant.},
}
@article {pmid30825476,
year = {2019},
author = {Li, P and Chen, X and Shen, Y and Li, H and Zou, Y and Yuan, G and Hu, P and Hu, H},
title = {Mucus penetration enhanced lipid polymer nanoparticles improve the eradication rate of Helicobacter pylori biofilm.},
journal = {Journal of controlled release : official journal of the Controlled Release Society},
volume = {300},
number = {},
pages = {52-63},
doi = {10.1016/j.jconrel.2019.02.039},
pmid = {30825476},
issn = {1873-4995},
abstract = {The resistance of Helicobacter pylori (H. pylori) to conventional antibiotic treatments becomes prevalent recently. The biofilm formation was found to be highly correlated with the antibiotic resistance of H. pylori in the last decades. Moreover, H. pylori colonizes on the digestive tract epithelium located under the mucus layers, which further reduces therapeutic efficacy as mucus layers trap and remove exogenous substances including drugs. Herein, we reported a novel lipid polymer nanoparticles (LPNs) to overcome both biofilm and mucus layers obstruction. LPNs employed chitosan nanoparticle (CS NPs) as the core, mixed lipid layer containing rhamnolipids (RHL) as the shell and the surface of LPNs was further modified with DSPE-PEG2000 to improve hydrophilicity. Clarithromycin (CLR), a first-line drug for H. pylori infection, was encapsulated in LPNs. LPNs, especially the formulation utilizing 100% of RHL as the lipid shell, exhibited excellent eradicating ability to H. pylori biofilm, which was mainly reflected in the significant reduction of biofilm biomass and viability, destruction of biofilm architecture and elimination of extracellular polymeric substances (EPS). The anti-biofilm activities of LPNs are related to: 1) the disrupting effect of RHL on biofilm matrix; 2) antibacterial effects of CLR and CS NPs on biofilm bacteria and 3) inhibitory effects of CS NPs and RHL on bacteria adhesion and biofilm formation. Furthermore, PEGylated LPNs could rapidly penetrate through mucus without interacting with mucins and effectively eradicate H. pylori biofilm under mucus layer. In conclusion, a novel approach of drug-containing LPNs that could penetrate through mucus layers and effectively eradicate H. pylori biofilm provides new ways to treat persistent H. pylori infections.},
}
@article {pmid30825355,
year = {2019},
author = {Issa, R and Chanishvili, N and Caplin, J and Kakabadze, E and Bakuradze, N and Makalatia, K and Cooper, I},
title = {Anti-biofilm potential of purified environmental bacteriophage preparations against early stage Pseudomonas aeruginosa biofilms.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14241},
pmid = {30825355},
issn = {1365-2672},
abstract = {AIMS: This paper presents the potential of environmentally-sourced bacteriophages to affect the growth of clinical isolates of Pseudomonas aeruginosa biofilms, and assesses the respective plaque morphotypes presented by each bacteriophage, in vitro.<br><br>METHODS AND RESULTS: Bacterial host strains were typed for their ability to produce the quorum sensing-controlled virulence factor pyocyanin, and then tested for bacteriophage susceptibility using the spot test method. The bacteriophages were co-administered with ciprofloxacin in order to determine whether the bacteriophages would demonstrate synergistic or antagonistic behaviour to the antibiotic in vitro. Results suggest a potential relationship between the bacteriophage plaque size and biofilm inhibition, where those producing smaller plaques appear to be more effective at reducing bacterial biofilm formation.<br><br>CONCLUSIONS: This phenomenon may be explained by a high adsorption rate leading to the rapid formation of smaller plaques, and greater biofilm reduction associated with the loss of viable bacterial cells before the cells can adhere to the surface and form a biofilm. Results from the co-administration of bacteriophage &amp; ciprofloxacin suggest that the two work synergistically to affect P. aeruginosa biofilms.<br><br>The data indicate enhanced efficacy of ciprofloxacin by ≥50%. This could offer an alternative strategy for targeting antibiotic-resistant infections. This article is protected by copyright. All rights reserved.},
}
@article {pmid30824455,
year = {2019},
author = {Jochim, A and Shi, T and Belikova, D and Schwarz, S and Peschel, A and Heilbronner, S},
title = {Methionine Limitation Impairs Pathogen Expansion and Biofilm Formation Capacity.},
journal = {Applied and environmental microbiology},
volume = {85},
number = {9},
pages = {},
doi = {10.1128/AEM.00177-19},
pmid = {30824455},
issn = {1098-5336},
abstract = {Multidrug-resistant bacterial pathogens are becoming increasingly prevalent, and novel strategies to treat bacterial infections caused by these organisms are desperately needed. Bacterial central metabolism is crucial for catabolic processes and provides precursors for anabolic pathways, such as the biosynthesis of essential biomolecules like amino acids or vitamins. However, most essential pathways are not regarded as good targets for antibiotic therapy since their products might be acquired from the environment. This issue raises doubts about the essentiality of such targets during infection. A putative target in bacterial anabolism is the methionine biosynthesis pathway. In contrast to humans, almost all bacteria carry methionine biosynthesis pathways which have often been suggested as putative targets for novel anti-infectives. While the growth of methionine auxotrophic strains can be stimulated by exogenous methionine, the extracellular concentrations required by most bacterial species are unknown. Furthermore, several phenotypic characteristics of methionine auxotrophs are only partly reversed by exogenous methionine. We investigated methionine auxotrophic mutants of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli (all differing in methionine biosynthesis enzymes) and found that each needed concentrations of exogenous methionine far exceeding that reported for human serum (∼30 µM). Accordingly, these methionine auxotrophs showed a reduced ability to proliferate in human serum. Additionally, S. aureus and P. aeruginosa methionine auxotrophs were significantly impaired in their ability to form and maintain biofilms. Altogether, our data show intrinsic defects of methionine auxotrophs. This result suggests that the pathway should be considered for further studies validating the therapeutic potential of inhibitors.IMPORTANCE New antibiotics that attack novel targets are needed to circumvent widespread resistance to conventional drugs. Bacterial anabolic pathways, such as the enzymes for biosynthesis of the essential amino acid methionine, have been proposed as potential targets. However, the eligibility of enzymes in these pathways as drug targets is unclear because metabolites might be acquired from the environment to overcome inhibition. We investigated the nutritional needs of methionine auxotrophs of the pathogens Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli We found that each auxotrophic strain retained a growth disadvantage at methionine concentrations mimicking those available in vivo and showed that biofilm biomass was strongly influenced by endogenous methionine biosynthesis. Our experiments suggest that inhibition of the methionine biosynthesis pathway has deleterious effects even in the presence of external methionine. Therefore, additional efforts to validate the effects of methionine biosynthesis inhibitors in vivo are warranted.},
}
@article {pmid30820766,
year = {2019},
author = {Hamilos, DL},
title = {Biofilm Formations in Pediatric Respiratory Tract Infection : Part 1: Biofilm Structure, Role of Innate Immunity in Protection Against and Response to Biofilm, Methods of Biofilm Detection, Pediatric Respiratory Tract Diseases Associated with Mucosal Biofilm Formation.},
journal = {Current infectious disease reports},
volume = {21},
number = {2},
pages = {6},
doi = {10.1007/s11908-019-0658-9},
pmid = {30820766},
issn = {1523-3847},
abstract = {PURPOSE OF REVIEW: Biofilm represents an organized structure of microorganisms within an extracellular matrix attached to a surface. While the importance of biofilm in prosthetic heart valve and catheter-related infections has been known since the 1980s, the role of mucosal biofilm in human disease pathogenesis has only recently been elucidated. It is now clear that mucosal biofilm is present in both healthy and pathologic states. The purpose of this review is to examine the role of mucosal biofilm in pediatric respiratory infections.<br><br>RECENT FINDINGS: Mucosal biofilm has been implicated in relationship to several pediatric respiratory infections, including tonsillitis, adenoiditis, otitis media with effusion, chronic rhinosinusitis, persistent endobronchial infection, and bronchiectasis. In these conditions, core pathogens are detected in the biofilm, biofilm organisms are often detected by molecular techniques when conventional cultures are negative, and biofilm presence is more extensive in relation to disease than in healthy tissues. In chronic rhinosinusitis, the presence of polymicrobial biofilm is also a predictor of poorer outcome following sinus surgery. Biofilm in the tonsillar and adenoidal compartments plays a distinct role in contributing to disease in the middle ear and sinuses. Key observations regarding the relevance of biofilm to pediatric respiratory infections include (1) the association between the presence of biofilm and persistent/recurrent and more severe disease in these tissues despite antibiotic treatment, (2) linkage between biofilm core pathogens and acute infections, and (3) interrelationship between biofilm presence in one tissue and persistent or recurrent infection in an adjacent tissue. A greater understanding of the significance of mucosal biofilm will undoubtedly emerge with the development of effective means of eradicating mucosal biofilm.},
}
@article {pmid30820691,
year = {2019},
author = {Chen, D and Cao, Y and Yu, L and Tao, Y and Zhou, Y and Zhi, Q and Lin, H},
title = {Characteristics and influencing factors of amyloid fibers in S. mutans biofilm.},
journal = {AMB Express},
volume = {9},
number = {1},
pages = {31},
doi = {10.1186/s13568-019-0753-1},
pmid = {30820691},
issn = {2191-0855},
support = {81570967//National Natural Science Foundation of China/ ; },
abstract = {There are signs that amyloid fibers exist in Streptococcus mutans biofilm recently. However, the characteristics of amyloid fibers and fibrillation influencing factors are unknown. In this study, we firstly used transmission electron microscopy (TEM) and atomic force microscopy (AFM) to observe the morphology of amyloid fibers in S. mutans. Then the extracted amyloid fibers from biofilm were studied for their characteristics. Further, the influencing factors, PH, temperature and eDNA, were investigated. Results showed there were mainly two morphologies of amyloid fibers in S. mutans, different in width. Amyloid fibers inhibitor-EGCG obviously destroyed biofilm at different stages, which is dose-dependent. The amount of amyloid fibers positively correlated with biofilm biomass in clinical isolates. Acidic pH and high temperature obviously accelerated amyloid fibrillation. During amyloid fibrillation, amyloid growth morphologies were observed by TEM and results showed two growth morphologies. Amyloid fibers formed complex with eDNA, which we call (a)eDNA. The molecular weight of (a)eDNA was similar to genomic DNA, greatly larger than that of eDNA in matrix. Combined use of DNase I and EGCG was more efficiently in inhibiting amyloid fibers and biofilm biomass. In conclusion, amyloid fibers are the crucial structures for S. mutans biofilm formation, showing two types of morphology. Acidic pH and temperature can obviously accelerate amyloid fibrillation. Amyloid fibers form complex with (a)eDNA and combined use of DNase and amyloid fiber inhibitor is more efficiently in inhibiting S. mutans biofilm formation.},
}
@article {pmid30820334,
year = {2019},
author = {Chan, S and Pullerits, K and Keucken, A and Persson, KM and Paul, CJ and Rådström, P},
title = {Bacterial release from pipe biofilm in a full-scale drinking water distribution system.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {9},
doi = {10.1038/s41522-019-0082-9},
pmid = {30820334},
issn = {2055-5008},
abstract = {Safe drinking water is delivered to the consumer through kilometres of pipes. These pipes are lined with biofilm, which is thought to affect water quality by releasing bacteria into the drinking water. This study describes the number of cells released from this biofilm, their cellular characteristics, and their identity as they shaped a drinking water microbiome. Installation of ultrafiltration (UF) at full scale in Varberg, Sweden reduced the total cell count to 1.5 × 103 ± 0.5 × 103 cells mL-1 in water leaving the treatment plant. This removed a limitation of both flow cytometry and 16S rRNA amplicon sequencing, which have difficulties in resolving small changes against a high background cell count. Following installation, 58% of the bacteria in the distributed water originated from the pipe biofilm, in contrast to before, when 99.5% of the cells originated from the treatment plant, showing that UF shifts the origin of the drinking water microbiome. The number of bacteria released from the biofilm into the distributed water was 2.1 × 103 ± 1.3 × 103 cells mL-1 and the percentage of HNA (high nucleic acid) content bacteria and intact cells increased as it moved through the distribution system. DESeq2 analysis of 16S rRNA amplicon reads showed increases in 29 operational taxonomic units (OTUs), including genera identified as Sphingomonas, Nitrospira, Mycobacterium, and Hyphomicrobium. This study demonstrated that, due to the installation of UF, the bacteria entering a drinking water microbiome from a pipe biofilm could be both quantitated and described.},
}
@article {pmid30820202,
year = {2019},
author = {Tahmourespour, A and Kasra-Kermanshahi, R and Salehi, R},
title = {Lactobacillus rhamnosus biosurfactant inhibits biofilm formation and gene expression of caries-inducing Streptococcus mutans.},
journal = {Dental research journal},
volume = {16},
number = {2},
pages = {87-94},
pmid = {30820202},
issn = {1735-3327},
abstract = {Background: It is cleared that some probiotic strains inhibit biofilm formation of oral bacteria, but its mechanisms are not clearly understood yet. It is proposed that one of the mechanisms can be biosurfactant production, a structurally diverse group of surface-active compounds synthesized by microorganisms. Hence, this study focused on the evaluation of the anti-biofilm and antiadhesive activities of the L. rhamnosus derived-biosurfactant against Streptococcus mutans and its effect on gtfB/C and ftf genes expression level.<br><br>Materials and Methods: In this in vitro study Lactobacillus rhamnosus ATCC7469 overnight culture was used for biosurfactant production. The biosurfactant effect on the surface tension reduction was confirmed by drop collapse method. Chemical bonds in the biosurfactant were identified by Fourier transform infrared (FTIR). Anti-biofilm and antiadhesive activities of the biosurfactant were determined on glass slides and in 96-well culture plates, respectively. The effect of the biosurfactant on gtfB/C and ftf genes expression level was also investigated after biofilm formation, total RNA extraction, and reverse transcription by quantitative real-time reverse transcriptase polymerase chain reaction (PCR) assay (quantitative PCR). The data were assessed by one-way analysis of variance in the Tukey-Kramer postdeviation test for all pairs. P < 0.05 was considered statistically significant.<br><br>Results: The FTIR results of biosurfactant showed that it was protein rich. It also showed anti-biofilm formation activity on the glass slide and antiadhesive activity till 40% on microtiter plate wells. It also showed a significant reduction (P < 0.05) in gtfB/C and ftf genes expression level.<br><br>Conclusion: L. rhamnosus-derived biosurfactant exhibits a significant inhibitory effect on biofilm formation ability of S. mutans due to downregulation of biofilm formation associated genes, gtfB/C and ftf. L. rhamnosus-derived biosurfactant with substantial antiadhesive activity is suitable candidates for use in new generations of microbial antiadhesive agents.},
}
@article {pmid30818374,
year = {2019},
author = {Ong, TH and Chitra, E and Ramamurthy, S and Ling, CCS and Ambu, SP and Davamani, F},
title = {Cationic chitosan-propolis nanoparticles alter the zeta potential of S. epidermidis, inhibit biofilm formation by modulating gene expression and exhibit synergism with antibiotics.},
journal = {PloS one},
volume = {14},
number = {2},
pages = {e0213079},
doi = {10.1371/journal.pone.0213079},
pmid = {30818374},
issn = {1932-6203},
abstract = {Staphylococcus epidermidis, is a common microflora of human body that can cause opportunistic infections associated with indwelling devices. It is resistant to multiple antibiotics necessitating the need for naturally occurring antibacterial agents. Malaysian propolis, a natural product obtained from beehives exhibits antimicrobial and antibiofilm properties. Chitosan-propolis nanoparticles (CPNP) were prepared using Malaysian propolis and tested for their effect against S. epidermidis. The cationic nanoparticles depicted a zeta potential of +40 and increased the net electric charge (zeta potential) of S. epidermidis from -17 to -11 mV in a concentration-dependent manner whereas, ethanol (Eth) and ethyl acetate (EA) extracts of propolis further decreased the zeta potential from -17 to -20 mV. Confocal laser scanning microscopy (CLSM) depicted that CPNP effectively disrupted biofilm formation by S. epidermidis and decreased viability to ~25% compared to Eth and EA with viability of ~60-70%. CPNP was more effective in reducing the viability of both planktonic as well as biofilm bacteria compared to Eth and EA. At 100 μg/mL concentration, CPNP decreased the survival of biofilm bacteria by ~70% compared to Eth or EA extracts which decreased viability by only 40%-50%. The morphology of bacterial biofilm examined by scanning electron microscopy depicted partial disruption of biofilm by Eth and EA extracts and significant disruption by CPNP reducing bacterial number in the biofilm by ~90%. Real time quantitative PCR analysis of gene expression in treated bacteria showed that genes involved in intercellular adhesion such as IcaABCD, embp and other related genes were significantly downregulated by CPNP. In addition to having a direct inhibitory effect on the survival of S. epidermidis, CPNP showed synergism with the antibiotics rifampicin, ciprofloxacin, vancomycin and doxycycline suggestive of effective treatment regimens. This would help decrease antibiotic treatment dose by at least 4-fold in combination therapies thereby opening up ways of tackling antibiotic resistance in bacteria.},
}
@article {pmid30817229,
year = {2019},
author = {Noie Oskouie, A and Hasani, A and Ahangarzadeh Rezaee, M and Soroush Bar Haghi, MH and Hasani, A and Soltani, E},
title = {A Relationship Between O-Serotype, Antibiotic Susceptibility and Biofilm Formation in Uropathogenic Escherichia coli.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2018.0330},
pmid = {30817229},
issn = {1931-8448},
abstract = {Uropathogenic Escherichia coli (UPEC) is a well-known pathogen that has perturbed the medical scenario because of its resistance to diverse therapeutic drugs and its ability to form a biofilm. Different O-serogroups are the prevalent cause of urinary tract infections (UTIs) along with their ability to form a biofilm. The present research aimed to assess antibiotic susceptibility, biofilm formation, and serotyping of UPEC isolates in conjunction with the demographic data. Antibiotic susceptibility was determined using the Kirby-Bauer method and biofilm formation was assessed phenotypically and at the molecular level. Serotyping was performed by multiplex PCR. A significant proportion of the total of 120 UPECs was isolated from women (p < 0.05). Most isolates were resistant to cefotaxime, ceftazidime, and tetracycline, but maintained their sensitivity to imipenem. O25, O15, O8, and O75 were the most commonly detected serogroups. Moreover, O25, O15, and O8 were the highest biofilm-producing serogroups among the UPEC isolates. Serogroups O75 and O21 were significantly associated with diabetic patients and subjects with renal disease, respectively (p < 0.05). Overall, our results show that UTI incidence in women should be a subject of concern. The high prevalence of the O25 serogroup associated with a specific antibiotic profile and a high percentage of biofilm formation suggests a close relation between serogroups and characteristic features of UPEC isolates.},
}
@article {pmid30816860,
year = {2019},
author = {Plattes, M},
title = {Presentation and evaluation of the zero-dimensional biofilm model 0DBFM.},
journal = {Water science and technology : a journal of the International Association on Water Pollution Research},
volume = {79},
number = {1},
pages = {35-40},
doi = {10.2166/wst.2018.450},
pmid = {30816860},
issn = {0273-1223},
abstract = {A zero-dimensional biofilm model, i.e. 0DBFM, has been developed for dynamic simulation of moving bed bioreactors (MBBRs). This mini-review aims at presenting and evaluating 0DBFM. 0DBFM is presented in Petersen matrix format and is based on the activated sludge model ASM1, which is an explicit and quite complex model (eight processes, 13 state variables, and 19 parameters) that has found wide application in engineering practice. 0DBFM is thus based on existing knowledge in biological wastewater treatment. The ASM1 approach has been confirmed by respirometry since the resulting respirograms were successfully simulated with ASM1. 0DBFM distinguishes between attached and suspended biomass and incorporates attachment of suspended matter from the bulk liquid onto the biofilm and detachment of biofilm into the bulk liquid. Still, 0DBFM respects the golden rule of modelling, which says that 'models should be as simple as possible and as complex as needed' and resists Occam's razor. The practicability of 0DBFM has been shown on a pilot-scale plant since nine days of wastewater treatment were successfully simulated and effluent quality was dynamically predicted. Finally, 0DBFM can be inspiring and the applicability of 0DBFM to other biofilm systems can be tested.},
}
@article {pmid30816484,
year = {2019},
author = {Sebaa, S and Boucherit-Otmani, Z and Courtois, P},
title = {Effects of tyrosol and farnesol on Candida albicans biofilm.},
journal = {Molecular medicine reports},
volume = {19},
number = {4},
pages = {3201-3209},
doi = {10.3892/mmr.2019.9981},
pmid = {30816484},
issn = {1791-3004},
abstract = {The present in vitro study examined the effects of the quorum‑sensing molecules farnesol and tyrosol on the development of Candida albicans biofilm in order to elucidate their role as novel adjuvants in oral hygiene. The investigation was conducted in C. albicans ATCC 10231 and C. albicans isolates from dentures and was performed in flat‑bottomed 96‑well polystyrene plates. Yeast growth and their capacity to form biofilms were evaluated following 24 and 48 h incubations at 37˚C in Sabouraud broth supplemented with 0.001‑3 mM farnesol and/or 1‑20 mM tyrosol. Yeast growth was assessed by turbidimetry and biofilms were quantitated by crystal violet staining, under aerobic and anaerobic conditions. The viability of the fungal cells was controlled by the culture of planktonic cells and by examination of the biofilms using fluorescence microscopy following staining with fluorescein diacetate and ethidium bromide. Farnesol at 3 mM exerted a stronger action when added at the beginning of biofilm formation (>50% inhibition) than when added to preformed biofilms (<10% inhibition). Similarly, tyrosol at 20 mM had a greater effect on biofilm formation (>80% inhibition) than on preformed biofilms (<40% inhibition). Despite significant reductions in attached biomass, yeast growth varied little in the presence of the investigated molecules, as corroborated by the turbidimetry, culture of supernatants on solid culture medium followed by counting of colony‑forming units and viability tests using fluorescence microscopy. At the highest tested concentration, the molecules had a greater effect during the initial phases of biofilm formation. The effect of farnesol during anaerobiosis was not significantly different from that observed during aerobiosis, unlike that of tyrosol during anaerobiosis, which exhibited slightly reduced yeast biofilm inhibition. In conclusion, the present study demonstrated the specific anti‑biofilm effect, independent of fungicidal or fungistatic action, of farnesol and tyrosol, as tested in C. albicans ATCC 10231 and 6 strains isolated from dentures. Prior to suggesting the use of these molecules for preventive purposes in oral hygiene, further studies are required in order to clarify the metabolic pathways and cellular mechanisms involved in their antibiofilm effect, as well as the repercussions on the oral microbiome.},
}
@article {pmid30816342,
year = {2019},
author = {Ueda, Y and Mashima, K and Miyazaki, M and Hara, S and Takata, T and Kamimura, H and Takagi, S and Jimi, S},
title = {Inhibitory effects of polysorbate 80 on MRSA biofilm formed on different substrates including dermal tissue.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {3128},
doi = {10.1038/s41598-019-39997-3},
pmid = {30816342},
issn = {2045-2322},
support = {17K10038//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; },
abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) forms biofilms on necrotic tissues and medical devices, and causes persistent infections. Surfactants act on biofilms, but their mode of action is still unknown. If used in the clinic, cytotoxicity in tissues should be minimized. In this study, we investigated the inhibitory effect of four different surfactants on MRSA biofilm formation, and found that a nonionic surfactant, polysorbate 80 (PS80), was the most suitable. The biofilm inhibitory effects resulted from the inhibition of bacterial adhesion to substrates rather than biofilm disruption, and the effective dose was less cytotoxic for 3T3 fibroblasts. However, the effects were substrate-dependent: positive for plastic, silicon, and dermal tissues, but negative for stainless-steel. These results indicate that PS80 is effective for prevention of biofilms formed by MRSA on tissues and foreign bodies. Therefore, PS80 could be used in medical practice as a washing solution for wounds and/or pretreatment of indwelling catheters.},
}
@article {pmid30815321,
year = {2019},
author = {Meesilp, N and Mesil, N},
title = {Effect of microbial sanitizers for reducing biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa on stainless steel by cultivation with UHT milk.},
journal = {Food science and biotechnology},
volume = {28},
number = {1},
pages = {289-296},
doi = {10.1007/s10068-018-0448-4},
pmid = {30815321},
issn = {2092-6456},
abstract = {Biofilm is a serious issue in the dairy factory due to it increases the opportunity for microbial contamination. Staphylococcus aureus and Pseudomonas aeruginosa are the bacteria capable to construct the biofilm on materials and equipments. Therefore, the bacterial growth and efficiency of sanitizing agents to solve the problems were evaluated. These bacteria grew well in UHT milk when they were cultivated at 37 °C, especially S. aureus. The exponential growth phase and biofilm on stainless steel were discovered by short contact time at 2 h. The mature stage of biofilm cycle was found at 4 h during bacteria growth and it was continuously constructed until 48 h. The 10, 24, and 48 h-old biofilm adhering on stainless steel were established with oxisan and chlorine used as microbial sanitizers. The 4% of sanitizing agents was the efficiency concentration to reduce biofilm on stainless steel up to 82% when these bacteria grew in UHT milk.},
}
@article {pmid30812996,
year = {2019},
author = {Murugesan, B and Arumugam, M and Pandiyan, N and Veerasingam, M and Sonamuthu, J and Samayanan, S and Mahalingam, S},
title = {Ornamental morphology of ionic liquid functionalized ternary doped N, P, F and N, B, F-reduced graphene oxide and their prevention activities of bacterial biofilm-associated with orthopedic implantation.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {98},
number = {},
pages = {1122-1132},
doi = {10.1016/j.msec.2019.01.052},
pmid = {30812996},
issn = {1873-0191},
abstract = {The multifunctional biological active material design for bone tissue engineering is essential to induce osteoblast cell proliferation and attachment. Adhesion of bacteria on biomaterials to produce biofilms can be major contributors to the pathogenesis of implant material associated infections. This research work focuses on NPF&amp; NBF elemental doping and functionalization of reduced graphene oxide using an imidazolium-based ionic liquid such as BMIM PF6 and BMIM BF4 by hydrothermal method. The resulting tri doped reduced graphene oxide (NPF-rGO and NBF-rGO) composite was further used as a scaffold for bone tissue engineering and anti-biofilm activities. The observation of the effect of NPF-rGO and NBF-rGO on the morphology, adhesion and cell proliferation of HOS cell was investigated. Moreover, the tri doped composite tested its antibiofilm properties against B. subtilis, E. coli, K. pneumoniae, and P. aeruginosa pathogenic bacteria. In-vitro studies clearly show the effectiveness of N, P, B, and F doping promoting the rGO mineralization, biocompatibility, and destruction of bacterial biofilm formation. The result of this study suggests that NPF-rGO and NBF-rGO hybrid material will be a promising scaffold for bone reaeration and implantation with a minimal bacterial infection.},
}
@article {pmid30811834,
year = {2019},
author = {Huigens Iii, RW and Abouelhassan, Y and Yang, H},
title = {Phenazine Antibiotic Inspired Discovery of Bacterial Biofilm-Eradicating Agents.},
journal = {Chembiochem : a European journal of chemical biology},
volume = {},
number = {},
pages = {},
doi = {10.1002/cbic.201900116},
pmid = {30811834},
issn = {1439-7633},
abstract = {Bacterial biofilms are surface-attached communities of slow-growing and non-replicating persister cells that demonstrate high levels of antibiotic tolerance. Biofilms occur in nearly 80% of infections and present unique challenges to our current arsenal of antibiotic therapies, all of which were initially discovered for their abilities to target rapidly-dividing, free-floating planktonic bacteria. Bacterial biofilms are credited as the underlying cause of chronic and recurring bacterial infections. Innovative approaches are required to identify new small molecules that operate through bacterial growth-independent mechanisms to effectively eradicate biofilms. One source of inspiration comes from within the lungs of young Cystic Fibrosis (CF) patients, who often endure persistent Staphylococcus aureus infections. As these CF patients age, Pseudomonas aeruginosa co-infects the lungs and utilize phenazine antibiotics to eradicate the established S. aureus infection. Our group has taken a special interest in this microbial competition strategy and we are investigating the potential of phenazine antibiotic-inspired compounds and synthetic analogues thereof to eradicate persistent bacterial biofilms. To discover new biofilm-eradicating agents, we have established an interdisciplinary research program involving synthetic medicinal chemistry, microbiology and molecular biology. From these efforts, we have identified a series of halogenated phenazines (HP) that potently eradicate bacterial biofilms and future work aims to translate these preliminary findings into groundbreaking clinical advances for the treatment of persistent biofilm infections.},
}
@article {pmid30811615,
year = {2019},
author = {Pelling, H and Nzakizwanayo, J and Milo, S and Denham, EL and MacFarlane, WM and Bock, LJ and Sutton, JM and Jones, BV},
title = {Bacterial biofilm formation on indwelling urethral catheters.},
journal = {Letters in applied microbiology},
volume = {68},
number = {4},
pages = {277-293},
doi = {10.1111/lam.13144},
pmid = {30811615},
issn = {1472-765X},
support = {MR/P015956/1//Medical Research Council/United Kingdom ; 206854/Z/17/Z//Wellcome Trust/United Kingdom ; },
abstract = {Urethral catheters are the most commonly deployed medical devices and used to manage a wide range of conditions in both hospital and community care settings. The use of long-term catheterization, where the catheter remains in place for a period >28 days remains common, and the care of these patients is often undermined by the acquisition of infections and formation of biofilms on catheter surfaces. Particular problems arise from colonization with urease-producing species such as Proteus mirabilis, which form unusual crystalline biofilms that encrust catheter surfaces and block urine flow. Encrustation and blockage often lead to a range of serious clinical complications and emergency hospital referrals in long-term catheterized patients. Here we review current understanding of bacterial biofilm formation on urethral catheters, with a focus on crystalline biofilm formation by P. mirabilis, as well as approaches that may be used to control biofilm formation on these devices. SIGNIFICANCE AND IMPACT OF THE STUDY: Urinary catheters are the most commonly used medical devices in many healthcare systems, but their use predisposes to infection and provide ideal conditions for bacterial biofilm formation. Patients managed by long-term urethral catheterization are particularly vulnerable to biofilm-related infections, with crystalline biofilm formation by urease producing species frequently leading to catheter blockage and other serious clinical complications. This review considers current knowledge regarding biofilm formation on urethral catheters, and possible strategies for their control.},
}
@article {pmid30811509,
year = {2019},
author = {McGaffey, M and Zur Linden, A and Bachynski, N and Oblak, M and James, F and Weese, JS},
title = {Manual polishing of 3D printed metals produced by laser powder bed fusion reduces biofilm formation.},
journal = {PloS one},
volume = {14},
number = {2},
pages = {e0212995},
doi = {10.1371/journal.pone.0212995},
pmid = {30811509},
issn = {1932-6203},
abstract = {Certain 3D printed metals and surface finishes may be better suited for canine patient specific orthopedic implants on the basis of minimizing potential bacterial biofilm growth. Thirty disks each of titanium alloy, stainless steel, and cobalt chromium alloy were 3D printed via laser powder bed fusion. Fifteen disks of each metal were subsequently polished. After incubation with a robust biofilm-forming methicillin-resistant Staphylococcus pseudintermedius isolate, disks were rinsed and sonicated to collect biofilm bacteria. Serial dilutions were plated on blood agar, and colony forming units were counted log (ln) transformed for analysis of variance. Interference microscopy quantified surface roughness for comparison to biofilm growth. Scanning electron microscopy on both pre- and post-sonicated disks confirmed biofilm presence and subsequent removal, and visualized surface features on cleaned disks. Significantly more bacteria grew on rough versus polished metal preparations (p < 0.0001). Titanium alloy had more bacterial biofilm growth compared to cobalt chromium alloy (p = 0.0001) and stainless steel (p < 0.0001). There were no significant growth differences between cobalt chromium alloy and stainless steel (p = 0.4737). Relationships between biofilm growth and surface roughness varied: positive with the rough preparations and negative with the smooth. Polished preparations had increased variance in surface roughness compared to rough preparations, and within disk variance predominated over between disk variance for all preparations with the exception of rough cobalt chromium alloy and rough stainless steel. Using scanning electron microscopy, bacterial biofilms tended to form in crevices. Overall, manual polishing of 3D printed surfaces significantly reduced biofilm growth, with preparation-specific relationships between surface roughness and biofilm growth. These results suggest that metallic implants produced by laser powder bed fusion should be polished. Further research will elucidate the optimal surface roughness per preparation to reduce potential biofilm formation and implant associated infection.},
}
@article {pmid30811265,
year = {2019},
author = {Aladarose, BE and Said, HS and Abdelmegeed, ES},
title = {Incidence of Virulence Determinants Among Enterococcal Clinical Isolates in Egypt and Its Association with Biofilm Formation.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2018.0320},
pmid = {30811265},
issn = {1931-8448},
abstract = {BACKGROUND: Although Enterococci compromise an essential part of normal gut microbiota of both animals and humans, they have emerged as a leading opportunistic pathogen causing infections. The pathogenesis of enterococci is attributed to an array of virulence determinants.<br><br>OBJECTIVES: This study aims to explore the prevalence and characteristics of enterococcal clinical isolates collected from Mansoura University Hospitals, Egypt, assess their ability to form biofilm, and the correlation with virulence determinants and antimicrobial resistance.<br><br>METHODS: A total of 70 Enterococcal clinical isolates were collected from different clinical sources between June and December 2016. Biofilm formation capacity was assessed, and characterization of virulence factors and antibiotic susceptibility was performed. Clonal relatedness between isolates was assessed using enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) approach.<br><br>RESULTS AND CONCLUSION: The molecular analysis demonstrated high genetic diversity among enterococcal clinical isolates. The gelE was the most frequently detected gene (91.4%), followed by asa1 (70%), esp (65.7%), and cylA (17.1%), while hyl was not detected in any isolate. Gelatinase activity was detected in 35.7%, while hemolysin and lipase activity was detected in 12.9% and 78.5%, respectively. Most of the enterococcal isolates were biofilm producers, of which 67.1% were strong/moderate biofilm producers. All linezolid-resistant isolates exhibited strong/moderate biofilm formation capacity. Strong/moderate biofilm formation was more frequently observed among esp-positive (esp+) and gelatinase nonproducing (gelatinase-) enterococcal isolates. Multiple regression analysis denoted that esp (odds ratio [OR] 5.371, p = 0.003) and gelatinase production (OR 0.264, p = 0.015) were associated with strong/moderate biofilm formation capacity. These findings suggest that esp gene positivity and gelatinase production may affect biofilm formation capacity among enterococcal clinical isolates.},
}
@article {pmid30810917,
year = {2018},
author = {Skowron, K and Hulisz, K and Gryń, G and Olszewska, H and Wiktorczyk, N and Paluszak, Z},
title = {Comparison of selected disinfectants efficiency against Listeria monocytogenes biofilm formed on various surfaces.},
journal = {International microbiology : the official journal of the Spanish Society for Microbiology},
volume = {21},
number = {1-2},
pages = {23-33},
doi = {10.1007/s10123-018-0002-5},
pmid = {30810917},
issn = {1139-6709},
abstract = {Listeria monocytogenes is a main etiological factor of listeriosis, spread mainly by food products. In recent years, an increasing number of patients with listeriosis and an augmentation in L. monocytogenes antibiotic resistance, e.g. to penicillin and ampicillin, has been reported. The aim of the study was to characterise the L. monocytogenes strains isolated from fish-processed food products. Species identification, based on the multiplex-PCR reaction, was performed, and the genetic similarity of the isolates was analysed with the RAPD technique. The strains, in the form of planktonic cells and a biofilm, were subjected to drug-susceptibility analysis, and the effect of disinfectants on the bacillus cells was evaluated. All of the analysed strains were of the Listeria monocytogenes species. Three genetically distant strains were detected, i.e. Lm I, Lm II and Lm III. Approximately 66.6% penicillin-resistant and 66.6% cotrimoxazole-resistant strains were found. No erythromycin-resistant strain was detected. The Lm II strain was simultaneously resistant to four antibiotics, i.e. penicillin, ampicillin, meropenem and cotrimoxazole. The strongest biofilm was formed on aluminium foil and the weakest on rubber. The tested disinfectant antibiofilm effectiveness was related to the type of surface. The most effective agent was paracetic acid and hydrogen peroxide (elimination rate 5.10-6.62 log CFU × cm-2 and 5.70-7.39 log CFU × cm-2 after 1- and 5-min exposure, respectively) and the least-sodium hydroxide (elimination rate 0.52-1.20 log CFU × cm-2 and 0.98-1.81 log CFU × cm-2 after 1- and 5-min exposure, respectively). Further studies on a greater number of L. monocytogenes strains are recommended.},
}
@article {pmid30810004,
year = {2018},
author = {Szymanek-Majchrzak, K and Wodzyńska, S and Młynarczyk, A and Młynarczyk, G},
title = {Production of extracellular polysaccharide and biofilm under different oxygen conditions by clinical isolates of Staphylococcus aureus non-susceptible to glycopeptides.},
journal = {Przeglad epidemiologiczny},
volume = {72},
number = {4},
pages = {487-498},
doi = {10.32394/pe.72.4.24},
pmid = {30810004},
issn = {0033-2100},
abstract = {INTRODUCTION: Staphylococcus aureus, which is able to produce an extracellular mucopolysaccharide (MP) and biofilm (SP), is an important etiologic agent in persistent and implant-related infections. This phenotype may be expressed in different levels and character depending on various environmental and/or global intracellular regulatory mechanisms. It may also be induced by sub-inhibitory concentrations of some antibiotics, for example vancomycin. The main aim of the study was to assess the ability to produce MP and SP in different oxygen conditions by clinical isolates of S.aureus nonsusceptible to glycopeptides.<br><br>MATERIALS AND METHODS: Clinical isolates of health-care associated methicillin resistant S. aureus (HA-MRSA) strains, non-susceptible to glycopeptides (GRSA, 47) and heterogeneous vancomycin intermediate S. aureus isolates (h-VISA, 8). Control group consisted of the following strains: 55 belonging to MRSA, vancomycin susceptible, VSSA and 19 as methicillin susceptible, MSSA/VSSA. The ability to produce MP was investigated according to Freeman method. SP production was tested by means of Christensen procedure.<br><br>RESULTS: In aerobic conditions MRSA/GRSA and MRSA/h-VISA isolates were the strongest mucopolysaccharide (SMP) producers (12.2% and 28.6% SMP/MP), but MSSA/VSSA were the most frequent MP (100%). In anaerobic atmosphere, all isolates from all groups were MP-positive. MRSA/h-VISA were the strongest MP producers (75% SMP/MP), but MSSA/VSSA were the most susceptible to oxidative stress (the percentage of SMP among MP for MSSA/VSSA increased by 15.8 times). Each evaluated group of clinical S. aureus isolates in aerobic condition had representation in SP positive phenotype: MRSA/GRSA and MRSA/h-VISA, 63.9% and 62.5%; MRSA/VSSA and MSSA/VSSA, respectively 80% and 94.7%. For all mentioned groups of bacteria, SSP variants were present and the amount of values was higher than in similar results obtained in CRA method. The strongest slime producers (60%) were h-VISA strains. The results obtained in Christensen method for anaerobic conditions, were not conclusive due to insufficient optimization of the test parameters.<br><br>SUMMARY AND CONCLUSIONS: Both methods reveal that MRSA isolates non-susceptible to glycopeptides are the strongest producers of both MP and SP. That is probably due to cell wall alterations and global regulatory system Agr disorders. The Christensen procedure allow to assess both ica- dependent and ica- independent (adhesive) mechanisms of slime production and allow to notice that, as a phenotyping “biofilm booster effect”. ica- dependent mechanism, which dominated in MSSA/VSSA strains, demonstrate phenotype with more susceptibility to oxygen stress conditions than adhesive one.},
}
@article {pmid30809273,
year = {2019},
author = {Yang, L and Zheng, C and Chen, Y and Shi, X and Ying, Z and Ying, H},
title = {Nitric oxide increases biofilm formation in Saccharomyces cerevisiae by activating the transcriptional factor Mac1p and thereby regulating the transmembrane protein Ctr1.},
journal = {Biotechnology for biofuels},
volume = {12},
number = {},
pages = {30},
doi = {10.1186/s13068-019-1359-1},
pmid = {30809273},
issn = {1754-6834},
abstract = {Background: Biofilms with immobilized cells encased in extracellular polymeric substance are beneficial for industrial fermentation. Their formation is regulated by various factors, including nitric oxide (NO), which is recognized as a quorum-sensing and signal molecule. The mechanisms by which NO regulates bacterial biofilms have been studied extensively and deeply, but were rarely studied in fungi. In this study, we observed the effects of low concentrations of NO on biofilm formation in Saccharomyces cerevisiae. Transcriptional and proteomic analyses were applied to study the mechanism of this regulation.<br><br>Results: Adding low concentrations of NO donors (SNP and NOC-18) enhanced biofilm formation of S. cerevisiae in immobilized carriers and plastics. Transcriptional and proteomic analyses revealed that expression levels of genes regulated by the transcription factor Mac1p was upregulated in biofilm cells under NO treatment. MAC1 promoted yeast biofilm formation which was independent of flocculation gene FLO11. Increased copper and iron contents, both of which were controlled by Mac1p in the NO-treated and MAC1-overexpressing cells, were not responsible for the increased biofilm formation. CTR1, one out of six genes regulated by MAC1, plays an important role in biofilm formation. Moreover, MAC1 and CTR1 contributed to the cells' resistance to ethanol by enhanced biofilm formation.<br><br>Conclusions: These findings suggest that a mechanism for NO-mediated biofilm formation, which involves the regulation of CTR1 expression levels by activating its transcription factor Mac1p, leads to enhanced biofilm formation. The role of CTR1 protein in yeast biofilm formation may be due to the hydrophobic residues in its N-terminal extracellular domain, and further research is needed. This work offers a possible explanation for yeast biofilm formation regulated by NO and provides approaches controlling biofilm formation in industrial immobilized fermentation by manipulating expression of genes involved in biofilm formation.},
}
@article {pmid30809097,
year = {2019},
author = {Zhang, Q and Gao, HY and Li, D and Li, Z and Qi, SS and Zheng, S and Bai, CS and Zhang, SH},
title = {Clinical outcome of Escherichia coli bloodstream infection in cancer patients with/without biofilm formation: a single-center retrospective study.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {359-371},
doi = {10.2147/IDR.S192072},
pmid = {30809097},
issn = {1178-6973},
abstract = {Background: Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) is one of the main antimicrobial-resistant pathogens. Little data are available on how biofilm formation (BF) contributes to EC-caused bloodstream infection (BSI) in cancer patients. This study investigated the impact of BF on clinical outcomes of cancer patients with EC-caused BSI.<br><br>Methods: Clinical outcome and microbiological characteristics including the presence of bla genes in ESBL-EC isolates were retrospectively collected from BSI cancer patients. Patients infected with ESBL-EC were compared with patients infected with third-generation cephalosporin-susceptible strains. Survival curves were generated by Kaplan-Meier analysis and the survival difference was assessed by the log-rank test. Risk factors for ESBL-EC infection, predictors of mortality, and outcome differences were determined by multivariate logistic regression and Cox regression analysis, respectively.<br><br>Results: A high prevalence of ESBL-EC with dominant blaCTX-M-15, blaCTX-M-15 plus blaTEM-52 genotype was found in BSI cancer patients. Independent risk factors for infection with ESBL-EC were cephalosporins, chemotherapy, and BF. Metastasis, ICU admission, BF-positive ESBL-EC, organ failure, and the presence of septic shock were revealed as predictors for mortality. The ESBL characteristic was associated with the BF phenotype, and the overall mortality was significantly higher in cancer patients with BF-positive ESBL-EC-caused BSI.<br><br>Conclusion: blaCTX-M-15 type ESBL-EC is highly endemic among cancer patients with BSI. BF is associated with multi-drug resistance by ESBL-EC and is also an independent risk factor of mortality for cancer patients with BSI. Our findings suggest that the combination of BF-positive ESBL-EC isolates with other appropriate laboratory indicators might benefit infection control and improve clinical outcomes.},
}
@article {pmid30808968,
year = {2019},
author = {Cabal, B and Sevillano, D and Fernández-García, E and Alou, L and Suárez, M and González, N and Moya, JS and Torrecillas, R},
title = {Bactericidal ZnO glass-filled thermoplastic polyurethane and polydimethyl siloxane composites to inhibit biofilm-associated infections.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {2762},
doi = {10.1038/s41598-019-39324-w},
pmid = {30808968},
issn = {2045-2322},
abstract = {This study investigates a novel approach to controlling biofilms of the most frequent pathogens implicated in the etiology of biomaterials-associated infections. New bactericidal filler based on a non-toxic glass, belonging to B2O3-SiO2-Al2O3-Na2O-ZnO system, was used to formulate composites of the most widely used polymers in biomedical applications [i.e. thermoplastic polyurethane (TPU) and polydimethyl siloxane (PDMS)], with varying percentage by weight of the bactericidal glass (5, 15, 25, 35, 50%). Glass-filled polymer composites show dramatically restricted bacterial colonisation and biofilm formation. They exhibit time- and dose-dependent killing, with maximal action at 5 days. The highest activity was found against S.epidermidis biofilm (99% of reduction), one of the most common cause of nosocomial infections. The tensile properties of the obtained glass-filled composites are comparable with the literature data concerning polymeric biomaterials for medical implants and devices. In addition, all the materials presented in this research, revealed an excellent biocompatibility. This was disclosed by cell viability values above 70%, none alteration on erythrocyte membrane or cell functionality in contact with materials (haemolytic index 0-2%), and absence of interferences in blood coagulation (intrinsic, extrinsic and final pathways).},
}
@article {pmid30808878,
year = {2019},
author = {de Barros Pinto, L and Lira, MLLA and Cavalcanti, YW and Dantas, ELA and Vieira, MLO and de Carvalho, GG and de Sousa, FB},
title = {Natural enamel caries, dentine reactions, dentinal fluid and biofilm.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {2841},
doi = {10.1038/s41598-019-38684-7},
pmid = {30808878},
issn = {2045-2322},
support = {MASTER SCHOLARSHIP//Ministry of Science, Technology and Innovation | Conselho Nacional de Desenvolvimento Cient&amp;#x00ED;fico e Tecnol&amp;#x00F3;gico (National Council for Scientific and Technological Development)/ ; MASTER SCHOLARSHIP//Ministry of Science, Technology and Innovation | Conselho Nacional de Desenvolvimento Cient&amp;#x00ED;fico e Tecnol&amp;#x00F3;gico (National Council for Scientific and Technological Development)/ ; UNDERGRADUATE RESEARCH SCHOLARSHIP//Ministry of Science, Technology and Innovation | Conselho Nacional de Desenvolvimento Cient&amp;#x00ED;fico e Tecnol&amp;#x00F3;gico (National Council for Scientific and Technological Development)/ ; UNDERGRADUATE RESEARCH SCHOLARSHIP//Ministry of Science, Technology and Innovation | Conselho Nacional de Desenvolvimento Cient&amp;#x00ED;fico e Tecnol&amp;#x00F3;gico (National Council for Scientific and Technological Development)/ ; },
abstract = {It is believed that penetration of dentinal fluid into natural enamel caries (NEC) is negligible because of the barrier created by underlying sclerotic dentine, but there are conflicting evidences on whether dentine subjacent to NEC is sclerotic or demineralized. This study aimed at investigating the relationship between NEC, subjacent dentine reactions, modification of dentinal fluid, and composition of cariogenic biofilm formed on the NEC surface. Proximal NEC (PNEC) lesions of human permanent posterior teeth were included in five experiments. Histologically, microradiographic analysis with contrast solution (MRC) in dentine revealed a decreased proportion of sclerotic dentine and an increased proportion of deep dentine demineralization compared to the classical stereomicroscopic histological analysis based on dentin color and translucency. Real-time MRC and 3D optical profilometry, and 3D microtomographic analysis evidenced a facilitated transport of modified dentinal fluid towards PNEC lesions. Cariogenic biofilm formed in vitro on the PNEC surface presented lower amounts of insoluble and soluble matrix polysaccharides when 2% chlorexidine was inserted in the pulp chamber. In conclusion, this study evidenced that dentine subjacent to PNEC is mostly demineralized, providing facilitated pathway for dentinal fluid to penetrate into PNEC and alter the composition of the biofilm formed on the PNEC surface.},
}
@article {pmid30808696,
year = {2019},
author = {Huang, Z and Wang, YH and Zhu, HZ and Andrianova, EP and Jiang, CY and Li, D and Ma, L and Feng, J and Liu, ZP and Xiang, H and Zhulin, IB and Liu, SJ},
title = {Cross Talk between Chemosensory Pathways That Modulate Chemotaxis and Biofilm Formation.},
journal = {mBio},
volume = {10},
number = {1},
pages = {},
doi = {10.1128/mBio.02876-18},
pmid = {30808696},
issn = {2150-7511},
mesh = {Biofilms/*growth &amp; development ; *Chemotaxis ; Comamonas testosteroni/genetics/*physiology ; *Gene Expression Regulation, Bacterial ; *Gene Regulatory Networks ; Histidine Kinase/metabolism ; Phosphorylation ; Protein Processing, Post-Translational ; Signal Transduction ; },
abstract = {Complex chemosensory systems control multiple biological functions in bacteria, such as chemotaxis, gene regulation, and cell cycle progression. Many species contain more than one chemosensory system per genome, but little is known about their potential interplay. In this study, we reveal cross talk between two chemosensory pathways that modulate chemotaxis and biofilm formation in Comamonas testosteroni We demonstrate that some chemoreceptors that govern chemotaxis also contribute to biofilm formation and these chemoreceptors can physically interact with components of both pathways. Finally, we show that the chemotaxis histidine kinase CheA can phosphorylate not only its cognate response regulator CheY2 but also one of the response regulators from the pathway mediating biofilm formation, FlmD. The phosphoryl group transfer from CheA to CheY2 is much faster than that from CheA to FlmD, which is consistent with chemotaxis being a fast response and biofilm formation being a much slower developmental process. We propose that cross talk between chemosensory pathways may play a role in coordination of complex behaviors in bacteria.IMPORTANCE In many bacteria, two or more homologous chemosensory pathways control several cellular functions, such as motility and gene regulation, in response to changes in the cell's microenvironment. Cross talk between signal transduction systems is poorly understood; while generally it is considered to be undesired, in some instances it might be beneficial for coregulation of complex behaviors. We demonstrate that several receptors from the pathway controlling motility can physically interact with downstream components of the pathway controlling biofilm formation. We further show that a kinase from the pathway controlling motility can also phosphorylate a response regulator from the pathway controlling biofilm formation. We propose that cross talk between two chemosensory pathways might be involved in coordination of two types of cell behavior-chemotaxis and biofilm formation.},
}
@article {pmid30807627,
year = {2019},
author = {Ishijima, M and de Avila, ED and Nakhaei, K and Shi, W and Lux, R and Ogawa, T},
title = {Ultraviolet Light Treatment of Titanium Suppresses Human Oral Bacterial Attachment and Biofilm Formation: A Short-Term In Vitro Study.},
journal = {The International journal of oral &amp; maxillofacial implants},
volume = {},
number = {},
pages = {},
doi = {10.11607/jomi.7444},
pmid = {30807627},
issn = {1942-4434},
abstract = {PURPOSE: Antibacterial dental implants and related prosthetic components could help to reduce infection and prevent peri-implantitis. The purpose of this study was to determine the effect of ultraviolet (UV) light treatment of titanium on biofilm formation of human oral bacteria.<br><br>MATERIALS AND METHODS: Machine-prepared commercially pure titanium disks were treated with UV light for 12 minutes. Human oral bacteria were seeded onto untreated and UV-treated disks. Early bacterial attachment to titanium was assessed at 12 hours. Surface topography of initial biofilms was evaluated by 3D scanning electron microscopy at 24 hours. The quantity and morphology of subsequent colony development and biofilm formation were examined by confocal laser scanning microscopy for up to 7 days.<br><br>RESULTS: Throughout the time course, significantly fewer bacterial cells attached to UV-treated titanium surfaces compared to untreated ones. While biofilm developed rapidly to a final thickness of about 16 μm by day 3 on untreated titanium, on UV-treated surfaces it remained below 8 μm, even at day 7. Similarly, UV treatment resulted in 70% less exopolysaccharides (EPS) volume than on untreated surfaces at day 7. This is consistent with the finding that EPS production per cell was significantly lower on UV-treated surfaces. Untreated titanium surfaces covered with biofilm were 5-fold rougher than the original machined surface, while UV-treated surfaces remained 2-fold rougher due to a significantly less biofilm formation.<br><br>CONCLUSION: UV treatment of titanium surfaces significantly reduces attachment of human oral bacteria and subsequent biofilm formation as well as EPS production for at least 7 days. UV treatment prevented the escalation of surface colonization, mitigating an unfavorable bacteriophilic cascade and environmental trigger for biofilm formation.},
}
@article {pmid30806125,
year = {2019},
author = {Kania, R and Vironneau, P and Dang, H and Bercot, B and Cambau, E and Verillaud, B and Camous, D and Lamers, G and Herman, P and Vicaut, E and Tessier, N and Van Den Abbeele, T},
title = {Bacterial biofilm in adenoids of children with chronic otitis media. Part I: a case control study of prevalence of biofilms in adenoids, risk factors and middle ear biofilms.},
journal = {Acta oto-laryngologica},
volume = {},
number = {},
pages = {1-6},
doi = {10.1080/00016489.2019.1571282},
pmid = {30806125},
issn = {1651-2251},
abstract = {BACKGROUND: Biofilms are communities of bacteria embedded in a self-produced glycocalyx matrix. Adenoids have been shown to harbor bacterial biofilms. Aim/objectives: To compare the prevalence of biofilms in adenoid of children with chronic otitis media (COM) (group1) versus a control group without any COM (group 2) having adenoids removed because of hypertrophy.<br><br>MATERIAL AND METHODS: One hundred and three children were prospectively enrolled in this case-control study, group 1 (n = 52) and group 2 (n = 51). The main outcome measurement was the prevalence of biofilm in adenoidectomy specimens analyzed using confocal laser scanning microscopy. Children in group 1 who had middle ear (ME) effusion and requiring the insertion of a tympanostomy tube underwent biopsy of the ME mucosa and effusion sampling.<br><br>RESULTS: Biofilms were found in adenoids' specimens of both groups and in the ME biopsy and effusion. The biofilm prevalence in adenoids was 63.5% (33/52) in group 1 and 47.1% (24/51) in group 2. Day nursery and previous antibiotics intake were significantly more frequent in group 1 than in group 2.<br><br>CONCLUSIONS AND SIGNIFICANCE: This case-control study demonstrates that adenoid tissue in children with COM contains more mucosal biofilms than adenoid tissue removed for hypertrophy. Biofilm was seen in ME biopsies and effusion.},
}
@article {pmid30805398,
year = {2019},
author = {Shahmoradi, M and Faridifar, P and Shapouri, R and Mousavi, SF and Ezzedin, M and Mirzaei, B},
title = {Determining the Biofilm Forming Gene Profile of Staphylococcus aureus Clinical Isolates via Multiplex Colony PCR Method.},
journal = {Reports of biochemistry &amp; molecular biology},
volume = {7},
number = {2},
pages = {181-188},
pmid = {30805398},
issn = {2322-3480},
abstract = {Background: Among hospitalized patients, Staphylococcus aureus (S. aureus) infections pose a serious health threat. The present study investigated the frequency of biofilm forming genes among clinical isolates S. aureus and their susceptibility to antibiotics.<br><br>Methods: The clinical samples were analyzed via standard biochemical assays for identifying different bacterium, which was then confirmed using the multiplex colony PCR method. Those samples identified as S. aureus were examined for the presence of the cna, fnbA, fnbB and pvl genes. The antibiotic susceptibility of the S. aureus isolates was then tested.<br><br>Results: Using the standard biochemical assay approach, 54 S. aureus strains were identified. However, when using the multiplex PCR method 50 S. aureus strains were identified among the clinical samples. The in vitro biofilm formation assays determined 3 (6%) strains of S. aureus to be strong biofilm forming, 15 (30%) of the isolates were determined to be moderate biofilm forming and, 32 (64%) were determined to be weak biofilm forming. Among the isolated strains, the specific frequencies of the biofilm forming genes were determined to be 31 (62%) for cna, 35 (70%) for fnbA, 13 (26%) for fnbB and 1 (2%) for pvl. In 11 (22%) of the isolated strains fnbA, fnbB and cna genes were all present. All strains were determined to be penicillin, amoxicillin and clavulanic acid resistant.<br><br>Conclusion: Due to the increase of the antibiotic resistance in biofilm producing S. aureus strains, rapid identification of antibiotic resistance can help to eliminate the infection effectively.},
}
@article {pmid30805068,
year = {2019},
author = {Filardo, S and Di Pietro, M and Tranquilli, G and Sessa, R},
title = {Biofilm in Genital Ecosystem: A Potential Risk Factor for Chlamydia trachomatis Infection.},
journal = {The Canadian journal of infectious diseases &amp; medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale},
volume = {2019},
number = {},
pages = {1672109},
doi = {10.1155/2019/1672109},
pmid = {30805068},
issn = {1712-9532},
abstract = {In healthy women, the cervicovaginal microbiota is mostly populated by Lactobacillus spp., the main host defense factor of the female genital tract. In addition to Lactobacilli, other microorganisms populate the cervicovaginal microbiota, like Candida spp. and Gardnerella vaginalis. The overgrowth of Candida spp. or G. vaginalis, known as biofilm-producing microorganisms in the genital ecosystem, may lead to microbial dysbiosis that increases the risk of acquiring sexually transmitted infections, like Chlamydia trachomatis. C. trachomatis, the leading cause of bacterial sexually transmitted diseases, is still considered an important public health problem worldwide because of the impact of asymptomatic infections on long-term reproductive sequelae, including pelvic inflammatory disease and infertility. The aim of our study was to investigate the interaction between C. trachomatis and the biofilm produced by Candida albicans or Gardnerella vaginalis, evaluating whether the biofilm can harbor C. trachomatis and influence its survival as well as its infectious properties. In order to do so, we developed an in vitro coculture transwell-based biofilm model. Our findings proved, for the first time, that C. trachomatis, an intracellular obligate pathogen, survived, for up to 72 hours after exposure, inside the biofilm produced by C. albicans or G. vaginalis, retaining its infectious properties, as evidenced by the typical chlamydial inclusions observed in the cell monolayer (chlamydial inclusion-forming units at 72 h: 9255 ± 1139 and 9873 ± 1015, respectively). In conclusion, our results suggest that the biofilm related to Candida or Gardnerella genital infections may act as a reservoir of C. trachomatis and, thus, contribute to the transmission of the infection in the population as well as to its dissemination into the upper genital tract, increasing the risk of developing severe reproductive sequelae.},
}
@article {pmid30804914,
year = {2019},
author = {Wang, Y and Wang, F and Wang, C and Li, X and Fu, L},
title = {Positive Regulation of Spoilage Potential and Biofilm Formation in Shewanella baltica OS155 via Quorum Sensing System Composed of DKP and Orphan LuxRs.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {135},
doi = {10.3389/fmicb.2019.00135},
pmid = {30804914},
issn = {1664-302X},
abstract = {The spoilage potential and biofilm formation of Shewanella baltica are reported to be regulated by Quorum sensing (QS) system from the phenotype point of view, but the specific mechanism is not fully understood. In the present study, the QS autoinducers were detected by UHPLC-MS/MS, cell density-dependent luxR-type genes were obtained through autoregulation experiments among a series of candidates in S. baltica OS155 (The SSO of large yellow croaker). The direct interaction between cyclo-(L-Pro-L-Phe) (PP) and LuxR01 as well as LuxR02 proteins was revealed via in vitro binding assay. Deletion of luxR-type genes (luxR01 and luxR02) impaired spoilage potential and biofilm formation of S. baltica OS155 in various degrees. Transcriptional analysis and qRT-PCR validation showed that spoilage and biofilm-related genes torS, speF, and pomA were down-regulated in luxR01 and luxR02 deletion strains. In addition, exogenous PP promoted spoilage potential and biofilm formation, which could be attenuated by luxR01 or luxR02 deletion. Our results revealed an explicit QS system employing PP as autoinducer and two orphan LuxRs as receptors which positively regulated spoilage capacity and biofilm formation via transcriptional regulation of corresponding genes in S. baltica OS155, which provides potential specific targets for seafood preservation involving QS system.},
}
@article {pmid30803538,
year = {2019},
author = {Kim, AR and Ahn, KB and Yun, CH and Park, OJ and Perinpanayagam, H and Yoo, YJ and Kum, KY and Han, SH},
title = {Lactobacillus plantarum Lipoteichoic Acid Inhibits Oral Multispecies Biofilm.},
journal = {Journal of endodontics},
volume = {45},
number = {3},
pages = {310-315},
doi = {10.1016/j.joen.2018.12.007},
pmid = {30803538},
issn = {1878-3554},
abstract = {INTRODUCTION: Apical periodontitis is an inflammatory disease in the periradicular region of teeth that results from infection by multispecies bacterial biofilm residing in the root canal system. In this study, we investigated whether Lactobacillus plantarum lipoteichoic acid (Lp.LTA) could inhibit multispecies oral pathogenic bacterial biofilm formation.<br><br>METHODS: Highly pure and structurally intact Lp.LTA was purified from L. plantarum. Actinomyces naeslundii, Lactobacillus salivarius, Streptococcus mutans, and Enterococcus faecalis were co-cultured to form oral multispecies biofilm in the presence or absence of Lp.LTA on culture plates or human dentin slices. Preformed biofilm was treated with or without Lp.LTA, followed by additional treatment with intracanal medicaments such as calcium hydroxide or chlorhexidine digluconate. Confocal microscopy and crystal violet assay were performed to determine biofilm formation. Biofilm on human dentin slices was visualized with a scanning electron microscope.<br><br>RESULTS: Biofilm formation of multispecies bacteria on the culture dishes was dose-dependently reduced by Lp.LTA compared with the nontreatment control group. Lp.LTA also inhibited multispecies biofilm formation on the dentin slices in a dose-dependent manner. Interestingly, Lp.LTA was shown to reduce preformed multispecies biofilm compared with the nontreatment group. Moreover, Lp.LTA potentiated the effectiveness of the intracanal medicaments in the removal of preformed multispecies biofilm.<br><br>CONCLUSIONS: These results suggest that Lp.LTA is a potential anti-biofilm agent for treatment or prevention of oral infectious disease, including apical periodontitis, which is mainly caused by multispecies bacterial biofilm.},
}
@article {pmid30803536,
year = {2019},
author = {Wu, S and Liu, Y and Zhang, H and Lei, L},
title = {The Susceptibility to Calcium Hydroxide Modulated by the Essential walR Gene Reveals the Role for Enterococcus faecalis Biofilm Aggregation.},
journal = {Journal of endodontics},
volume = {45},
number = {3},
pages = {295-301.e2},
doi = {10.1016/j.joen.2018.11.011},
pmid = {30803536},
issn = {1878-3554},
abstract = {INTRODUCTION: Enterococcus faecalis is considered a predominant pathogen for persistent periapical infections and in addition is reportedly resistant to calcium hydroxide medication. The WalRK 2-component system of E. faecalis is essential for environmental adaptation, survival, and virulence. The goal of this study was to investigate the potential roles of walR in the regulation of biofilm aggregation, alkaline stress, and susceptibility to calcium hydroxide (CH) medication.<br><br>METHODS: Antisense walR RNA (aswalR) overexpression strains were constructed. Exopolysaccharide (EPS) production and bacterial viability of E. faecalis biofilms were evaluated by confocal laser scanning microscopy. Quantitative real-time polymerase chain reaction was used to investigate the expressions of virulent factor genes. The proportion of viable bacteria and EPS production in dentin were assessed after CH medication.<br><br>RESULTS: We showed that walR interference by aswalR RNA leads to a reduction in the dextran-dependent aggregation in E. faecalis biofilm. The overexpression of aswalR reduced the transcripts of the virulence genes and alkaline stress tolerance ability. Furthermore, the down-regulation of walR sensitized E. faecalis in infected canals to CH medication associated with inhibiting EPS synthesis.<br><br>CONCLUSIONS: The data suggest a role for the walR regulator in the susceptibility to CH associated with dispelling the EPS matrix, which could be explored as a potential supplementary therapy for the management of root canal infection.},
}
@article {pmid30803159,
year = {2019},
author = {Hengzhuang, W and Green, K and Pressler, T and Skov, M and Katzenstein, TL and Wu, X and Høiby, N},
title = {Optimization of colistin dosing regimen for cystic fibrosis patients with chronic Pseudomonas aeruginosa biofilm lung infections.},
journal = {Pediatric pulmonology},
volume = {},
number = {},
pages = {},
doi = {10.1002/ppul.24269},
pmid = {30803159},
issn = {1099-0496},
support = {//University of Copenhagen Research Center for Control of Antibiotic Resistance/ ; },
abstract = {OBJECTIVE: The present study was performed to explore dosing regimens of colistin in patients of cystic fibrosis (CF) with Pseudomonas aeruginosa chronic biofilm lung infection.<br><br>METHODS: Ten CF patients were involved. One dose colistimethate sodium (CMS) of 6 MIU (million international units) and 9 MIU were administered by intravenous infusion over 45 and 90 min. Venous blood was collected at different time points after the infusion of CMS. Pharmacokinetic parameters of colistin were calculated. Minimum inhibitory concentration for planktonic P. aeruginosa, minimum biofilm inhibitory concentration and minimum biofilm eradication concentration of P. aeruginosa were determined. Monte Carlo simulation was performed to determine the clinical probability of target attainment of different dosing regimens of colistin in CF patients.<br><br>RESULTS: For 90 min (6 MIU), 45 min (6 MIU), and 45 min (9 MIU) intravenous infusion of colistin, Cmax was 8.9 ± 1.8, 15 ± 5.5, and 31.7 ± 5.3 μg/mL, respectively; Tmax was 1.2 ± 0.4, 0.7 ± 0.2, and 0.8 ± 0.2 h, respectively; AUCtot were 31 ± 3.8, 34 ± 10, and 135 ± 31mg · h/L, respectively; t1/2 was 2.1 ± 0.4, 2 ± 0.3, and 3.3 ± 0.4 h, respectively. MBIC and MBEC of colistin on biofilms at 24 h period treatment were 16-128 μg/mL for non-mucoid and mucoid biofilms of P. aeruginosa. For 90 min (6 MIU), 45 min (6 MIU) and 45 min iv infusion (9 MIU) with one dose colistin, PTA was 49.8%, 53.8%, 99.4% for planktonic infection, and 11.3%, 14.6%, 65.3%, respectively for biofilm infection.<br><br>CONCLUSIONS: colistin treatment using 45 min iv infusion is better than 90 min iv infusion in this study. Colistin dosage of 9 MIU is better than 6 MIU on both planktonic and biofilm infections of P. aeruginosa in this study.},
}
@article {pmid30803151,
year = {2019},
author = {Khan, I and Kanugala, S and Shareef, MA and Ganapathi, T and Shaik, AB and Shekar, KC and Kamal, A and Kumar, CG},
title = {Synthesis of new bis-pyrazole linked hydrazides and their in vitro evaluation as antimicrobial and anti-biofilm agents: A mechanistic role on ergosterol biosynthesis inhibition in Candida albicans.},
journal = {Chemical biology &amp; drug design},
volume = {},
number = {},
pages = {},
doi = {10.1111/cbdd.13509},
pmid = {30803151},
issn = {1747-0285},
abstract = {Literature reports suggest that pyrazoles and hydrazides are potential antimicrobial pharmocophores. Considering this fact, a series of nineteen conjugates containing hybrids of bis-pyrazole scaffolds joined through a hydrazide linker were synthesized and further evaluated for their antimicrobial activity against a panel of Gram-positive and Gram-negative bacteria along with Candida albicansMTCC 3017 strain. Although the derivatives exhibited good antibacterial activity, some of the derivatives (13d, 13j, 13l, 13p, and 13r) showed excellent anti-Candida activity with MICs values of 3.9 μg/ml, which was equipotent to that of the standard Miconazole (3.9 μg/ml), which has inspired us to further explore their anti-Candida activity. The same compounds were also tested for anti-biofilm studies against various Candida strains and among them, compounds 13l and 13r efficiently inhibited the formation of fungal biofilms. Field emission scanning electron micrographs revealed that one of the promising compound 13r showed cell damage and in turn cell death of the Candida strain. These potential conjugates (13l and 13r) also demonstrated promising ergosterol biosynthesis inhibition against some of the strains C. albicans, which were further validated through molecular docking studies. In silico computational studies were carried out to predict the binding modes and pharmacokinetic parameters of these conjugates.},
}
@article {pmid30802983,
year = {2019},
author = {Ledwoch, K and Said, J and Norville, P and Maillard, JY},
title = {Artificial dry surface biofilm models for testing the efficacy of cleaning and disinfection.},
journal = {Letters in applied microbiology},
volume = {68},
number = {4},
pages = {329-336},
doi = {10.1111/lam.13143},
pmid = {30802983},
issn = {1472-765X},
support = {//GAMA Healthcare though Cardiff University/ ; },
abstract = {Dry surface biofilms (DSB) harbouring pathogens are widespread in healthcare settings, are difficult to detect and are resistant to cleaning and disinfection interventions. Here, we describe a practical test protocol to palliate the lack of standard efficacy test methods for DSB. Staphylococcus aureus DSB were produced over a 12-day period, grown with or without the presence of organic matter, and their composition and viability were evaluated. Disinfectant treatment was conducted with a modified ASTM2967-15 test and reduction in viability, transferability and biofilm regrowth post-treatment were measured. Dry surface biofilms produced over a 12-day period had a similar carbohydrates, proteins and DNA content, regardless of the presence or absence of organic matter. The combination of sodium hypochlorite (1000 ppm) and a microfiber cloth was only effective against DSB in the absence of organic load. With the increasing concerns of the uncontrolled presence of DSB in healthcare settings, the development of effective intervention model in the presence of organic load is appropriate for the testing of biocidal products, while the use of three parameters, log10 reduction, transferability and regrowth, provides an accurate and practical measurement of product efficacy. SIGNIFICANCE AND IMPACT OF THE STUDY: The widespread presence of biofilms on dry surfaces in healthcare settings has been recently documented. These dry surface biofilms (DSB) present an unprecedented challenge to cleaning and disinfection processes. Here, we describe a practical efficacy protocol based on an in vitro Staphylococcus aureus DSB model. The protocol measures reduction in viability, transferability and biofilm regrowth post-treatment to provide altogether a practical assessment of product efficacy against dry surface biofilms.},
}
@article {pmid30801748,
year = {2019},
author = {Kim, HW and Chung, DH and Kim, SA and Rhee, MS},
title = {Synergistic cranberry juice combinations with natural-borne antimicrobials for the eradication of uropathogenic Escherichia coli biofilm within a short time.},
journal = {Letters in applied microbiology},
volume = {68},
number = {4},
pages = {321-328},
doi = {10.1111/lam.13140},
pmid = {30801748},
issn = {1472-765X},
support = {NRF-2016R1A2B2012743//National Research Foundation of Korea/ ; },
abstract = {Urinary tract infections (UTI), one of the most common diseases in humans, are caused primarily by uropathogenic Escherichia coli (UPEC). Cranberry juice (CB) is a widely known prophylaxis for UTI, but the treatment of CB alone could not effectively eradicate preformed UPEC biofilms. The aim of this study was to develop enforced CB composites within a short time by adding a small quantity of natural borne antimicrobials. UPEC biofilms (initial: 6·0 log CFU per cm2), formed on silicone coupons in artificial urine medium, were exposed to CB (4-8%), caprylic acid (CAR; 0·025-0·05%) and thymol (TM; 0·025-0·05%) at 37°C for 1 min. Individual treatment of each compound did not show the significant antibacterial effect on UPEC biofilms (P > 0·05). Otherwise, the survivor counts of biofilms were synergistically reduced with CB containing any of the antimicrobials. For example combined treatment with CB (8%) + CAR (0·05%) + TM (0·05%) resulted in a 6 log reduction in UPEC populations in the biofilm (no detectable bacteria remained) with 4·6 log of synergistic bactericidal effect. The confocal laser scanning microscope images indicated that any composites including TM might result in biofilm detachment from the surface. The present method is cost-effective and more acceptable to consumers as it is based on the synergistic interaction of natural borne antimicrobials. The results of this study could be widely applicable in the functional food, medical and healthcare field. SIGNIFICANCE AND IMPACT OF THE STUDY: Anti-biofilm effect of cranberry juice (CB) has been focused mainly on inhibiting biofilm formation of uropathogenic Escherichia coli (UPEC); however, combined treatment with natural borne antimicrobials derived from coconut oil (caprylic acid) and oregano essential oil (thymol) could synergistically enhance its eradicating activity against biofilms. This study developed novel CB composites showing marked anti-biofilm effects (complete eradication of UPEC biofilms within just 1 min).},
}
@article {pmid30801031,
year = {2019},
author = {Chouikha, I and Sturdevant, DE and Jarrett, C and Sun, YC and Hinnebusch, BJ},
title = {Differential Gene Expression Patterns of Yersinia pestis and Yersinia pseudotuberculosis during Infection and Biofilm Formation in the Flea Digestive Tract.},
journal = {mSystems},
volume = {4},
number = {1},
pages = {},
doi = {10.1128/mSystems.00217-18},
pmid = {30801031},
issn = {2379-5077},
abstract = {Yersinia pestis, the etiologic agent of plague, emerged as a fleaborne pathogen only within the last 6,000 years. Just five simple genetic changes in the Yersinia pseudotuberculosis progenitor, which served to eliminate toxicity to fleas and to enhance survival and biofilm formation in the flea digestive tract, were key to the transition to the arthropodborne transmission route. To gain a deeper understanding of the genetic basis for the development of a transmissible biofilm infection in the flea foregut, we evaluated additional gene differences and performed in vivo transcriptional profiling of Y. pestis, a Y. pseudotuberculosis wild-type strain (unable to form biofilm in the flea foregut), and a Y. pseudotuberculosis mutant strain (able to produce foregut-blocking biofilm in fleas) recovered from fleas 1 day and 14 days after an infectious blood meal. Surprisingly, the Y. pseudotuberculosis mutations that increased c-di-GMP levels and enabled biofilm development in the flea did not change the expression levels of the hms genes responsible for the synthesis and export of the extracellular polysaccharide matrix required for mature biofilm formation. The Y. pseudotuberculosis mutant uniquely expressed much higher levels of Yersinia type VI secretion system 4 (T6SS-4) in the flea, and this locus was required for flea blockage by Y. pseudotuberculosis but not for blockage by Y. pestis. Significant differences between the two species in expression of several metabolism genes, the Psa fimbrial genes, quorum sensing-related genes, transcription regulation genes, and stress response genes were evident during flea infection. IMPORTANCE Y. pestis emerged as a highly virulent, arthropod-transmitted pathogen on the basis of relatively few and discrete genetic changes from Y. pseudotuberculosis. Parallel comparisons of the in vitro and in vivo transcriptomes of Y. pestis and two Y. pseudotuberculosis variants that produce a nontransmissible infection and a transmissible infection of the flea vector, respectively, provided insights into how Y. pestis has adapted to life in its flea vector and point to evolutionary changes in the regulation of metabolic and biofilm development pathways in these two closely related species.},
}
@article {pmid30800673,
year = {2019},
author = {Zhou, Y and Wang, S and Zhou, X and Zou, Y and Li, M and Peng, X and Ren, B and Xu, HHK and Weir, MD and Cheng, L and Chen, Y and Han, Q},
title = {Short-Time Antibacterial Effects of Dimethylaminododecyl Methacrylate on Oral Multispecies Biofilm In Vitro.},
journal = {BioMed research international},
volume = {2019},
number = {},
pages = {6393470},
doi = {10.1155/2019/6393470},
pmid = {30800673},
issn = {2314-6141},
support = {R01 DE017974/DE/NIDCR NIH HHS/United States ; },
abstract = {Quaternary ammonium compounds constitute a large group of antibacterial chemicals with a potential for inhibiting dental plaque. The aims of this study were to evaluate short-time antibacterial and regulating effects of dimethylaminododecyl methacrylate (DMADDM) on multispecies biofilm viability, reformation, and bacterial composition in vitro. DMADDM, chlorhexidine (CHX), and sodium fluoride (NaF) were chosen in the present study. Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii were used to form multispecies biofilm. Cytotoxicity assay was used to determine the optimal tested concentration. 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and resazurin test of biofilm were conducted to study the biomass changes and metabolic changes of controlled multispecies biofilm. Scanning electron microscopy (SEM) was used to observe biofilm images. TaqMan real-time polymerase chain reaction was performed to evaluate the proportion change in multispecies biofilm of different groups. Cytotoxicity assay showed that there existed a certain concentration application range for DMADDM, CHX, and NaF. MTT assay and resazurin test results showed that DMADDM and CHX groups decreased multispecies biofilm growth and metabolic activity (p < 0.05), no matter after 1 min or 5 min direct contact killing or after 24 h regrowth. The proportion of S. mutans decreased steadily in DMADDM and CHX groups after 1 min and 5 min direct contact killing and 24 h regrowth, compared to control groups. A novel DMADDM-containing solution was developed, achieving effective short-time antibacterial effects and regulation ability of biofilm formation.},
}
@article {pmid30800115,
year = {2019},
author = {Grassi, L and Batoni, G and Ostyn, L and Rigole, P and Van den Bossche, S and Rinaldi, AC and Maisetta, G and Esin, S and Coenye, T and Crabbé, A},
title = {The Antimicrobial Peptide lin-SB056-1 and Its Dendrimeric Derivative Prevent Pseudomonas aeruginosa Biofilm Formation in Physiologically Relevant Models of Chronic Infections.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {198},
doi = {10.3389/fmicb.2019.00198},
pmid = {30800115},
issn = {1664-302X},
abstract = {Antimicrobial peptides (AMPs) are promising templates for the development of novel antibiofilm drugs. Despite the large number of studies on screening and optimization of AMPs, only a few of these evaluated the antibiofilm activity in physiologically relevant model systems. Potent in vitro activity of AMPs often does not translate into in vivo effectiveness due to the interference of the host microenvironment with peptide stability/availability. Hence, mimicking the complex environment found in biofilm-associated infections is essential to predict the clinical potential of novel AMP-based antimicrobials. In the present study, we examined the antibiofilm activity of the semi-synthetic peptide lin-SB056-1 and its dendrimeric derivative (lin-SB056-1)2-K against Pseudomonas aeruginosa in an in vivo-like three-dimensional (3-D) lung epithelial cell model and an in vitro wound model (consisting of an artificial dermis and blood components at physiological levels). Although moderately active when tested alone, lin-SB056-1 was effective in reducing P. aeruginosa biofilm formation in association with 3-D lung epithelial cells in combination with the chelating agent EDTA. The dimeric derivative (lin-SB056-1)2-K demonstrated an enhanced biofilm-inhibitory activity as compared to both lin-SB056-1 and the lin-SB056-1/EDTA combination, reducing the number of biofilm-associated bacteria up to 3-Log units at concentrations causing less than 20% cell death. Biofilm inhibition by (lin-SB056-1)2-K was reported both for the reference strain PAO1 and cystic fibrosis lung isolates of P. aeruginosa. In addition, using fluorescence microscopy, a significant decrease in biofilm-like structures associated with 3-D cells was observed after peptide exposure. Interestingly, effectiveness of (lin-SB056-1)2-K was also demonstrated in the wound model with a reduction of up to 1-Log unit in biofilm formation by P. aeruginosa PAO1 and wound isolates. Overall, combination treatment and peptide dendrimerization emerged as promising strategies to improve the efficacy of AMPs, especially under challenging host-mimicking conditions. Furthermore, the results of the present study underlined the importance of evaluating the biological properties of novel AMPs in in vivo-like model systems representative of specific infectious sites in order to make a more realistic prediction of their therapeutic success, and avoid the inclusion of unpromising peptides in animal studies and clinical trials.},
}
@article {pmid30799091,
year = {2019},
author = {Alves-Barroco, C and Roma-Rodrigues, C and Balasubramanian, N and Guimarães, MA and Ferreira-Carvalho, BT and Muthukumaran, J and Nunes, D and Fortunato, E and Martins, R and Santos-Silva, T and Figueiredo, AMS and Fernandes, AR and Santos-Sanches, I},
title = {Biofilm development and computational screening for new putative inhibitors of a homolog of the regulatory protein BrpA in Streptococcus dysgalactiae subsp. dysgalactiae.},
journal = {International journal of medical microbiology : IJMM},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijmm.2019.02.001},
pmid = {30799091},
issn = {1618-0607},
abstract = {Streptococcus dysgalactiae subsp. dysgalactiae (SDSD), a Lancefield group C streptococci (GCS), is a frequent cause of bovine mastitis. This highly prevalent disease is the costliest in dairy industry. Adherence and biofilm production are important factors in streptoccocal pathogenesis. We have previously described the adhesion and internalization of SDSD isolates in human cells and now we describe the biofilm production capability of this bacterium. In this work we integrated microbiology, imaging and computational methods to evaluate the biofilm production capability of SDSD isolates; to assess the presence of biofilm regulatory protein BrpA homolog in the biofilm producers; and to predict a structural model of BrpA-like protein and its binding to putative inhibitors. Our results show that SDSD isolates form biofilms on abiotic surface such as glass (hydrophilic) and polystyrene (hydrophobic), with the strongest biofilm formation observed in glass. This ability was mainly associated with a proteinaceous extracellular matrix, confirmed by the dispersion of the biofilms after proteinase K and trypsin treatment. The biofilm formation in SDSD isolates was also confirmed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Under SEM observation, VSD16 isolate formed cell aggregates during biofilm growth while VSD9 and VSD10 formed smooth and filmy layers. We show that brpA-like gene is present and expressed in SDSD biofilm-producing isolates and its expression levels correlated with the biofilm production capability, being more expressed in the late exponential phase of planktonic growth compared to biofilm growth. Fisetin, a known biofilm inhibitor and a putative BrpA binding molecule, dramatically inhibited biofilm formation by the SDSD isolates but did not affect planktonic growth, at the tested concentrations. Homology modeling was used to predict the 3D structure of BrpA-like protein. Using high throughput virtual screening and molecular docking, we selected five ligand molecules with strong binding affinity to the hydrophobic cleft of the protein, making them potential inhibitor candidates of the SDSD BrpA-like protein. These results warrant further investigations for developing novel strategies for SDSD anti-biofilm therapy.},
}
@article {pmid30798554,
year = {2019},
author = {Naudin, B and Heins, A and Pinhal, S and Dé, E and Nicol, M},
title = {BioFlux™ 200 Microfluidic System to Study A. baumannii Biofilm Formation in a Dynamic Mode of Growth.},
journal = {Methods in molecular biology (Clifton, N.J.)},
volume = {1946},
number = {},
pages = {167-176},
doi = {10.1007/978-1-4939-9118-1_16},
pmid = {30798554},
issn = {1940-6029},
abstract = {The ability of A. baumannii to develop biofilms on a wide range of surfaces can be associated to its persistence in hospital settings and the emergence of recalcitrant and chronic infections. Few compounds are available to eradicate A. baumannii biofilms, and most of them have been tested for their antibiofilm properties in static conditions. Microfluidics systems as BioFlux™ system are now available for studying A. baumannii biofilm formation in dynamic conditions. Here, we described the use of this system for studying the biofilm development of the reference strain A. baumannii ATCC 17978 in a dynamic mode. We showed how to test the activity of an antibiotic (colistin at the MIC concentration, 0.5 μg/mL) in these conditions of growth.},
}
@article {pmid30798553,
year = {2019},
author = {Biswas, I and Mettlach, J},
title = {A Simple Static Biofilm Assay for Acinetobacter baumannii.},
journal = {Methods in molecular biology (Clifton, N.J.)},
volume = {1946},
number = {},
pages = {159-165},
doi = {10.1007/978-1-4939-9118-1_15},
pmid = {30798553},
issn = {1940-6029},
support = {P20 GM113117/GM/NIGMS NIH HHS/United States ; },
abstract = {Acinetobacter baumannii and other Acinetobacter spp. display biofilm formation on abiotic surfaces. The degree of biofilm formation varies considerably depending on the isolates. While culturing, bacteria tend to attach to abiotic surfaces, and some surfaces perform better than others. Numerous methods are available to study in vitro biofilm formation by bacteria under static growth, and they basically rely upon culturing the bacteria in an ampule followed by staining the bacterial growth attached to the abiotic surface with a suitable dye such as crystal violet to visualize the biofilm. Subsequently, the dye is eluted with a suitable solvent, and optical density is measured to quantify the attached bacterial mass. In this chapter, we provide a basic and simple yet a powerful method to study biofilm formation by A. baumannii grown under static conditions.},
}
@article {pmid30798544,
year = {2019},
author = {Ravi, NS and Aslam, RF and Veeraraghavan, B},
title = {A New Method for Determination of Minimum Biofilm Eradication Concentration for Accurate Antimicrobial Therapy.},
journal = {Methods in molecular biology (Clifton, N.J.)},
volume = {1946},
number = {},
pages = {61-67},
doi = {10.1007/978-1-4939-9118-1_6},
pmid = {30798544},
issn = {1940-6029},
abstract = {Antimicrobial susceptibility testing (AST) is an important technique to find the susceptibility pattern of clinical isolates in order to administer the appropriate drug. One such technique is minimum inhibitory concentration (MIC), which not only identifies the right drug but also suggests the appropriate concentration necessary to neutralize the organisms in planktonic form. MIC can vary in case of adherent organisms since they form biofilms and activate survival mechanisms like quorum sensing. Here we have strategized a new method which used an inoculator plate, a resazurin dye, and a standard plate to identify minimum biofilm eradication concentration (MBEC) of adherent organisms.},
}
@article {pmid30798240,
year = {2019},
author = {Rajeev, M and Sushmitha, TJ and Toleti, SR and Pandian, SK},
title = {Culture dependent and independent analysis and appraisal of early stage biofilm-forming bacterial community composition in the Southern coastal seawater of India.},
journal = {The Science of the total environment},
volume = {666},
number = {},
pages = {308-320},
doi = {10.1016/j.scitotenv.2019.02.171},
pmid = {30798240},
issn = {1879-1026},
abstract = {Microbial aggregation on artificial surfaces is a fundamental phenomenon in aquatic systems that lead to biofouling, corrosion and influence the buoyancy of plastic materials. Despite the maritime activities and with nearshore large industrial sector, Laccadive Sea in the Indian Ocean has rarely been investigated for characterizing early biofilm-forming bacterial community. The present investigation was aimed to catalogue the primary colonizers on artificial surfaces and their comparison with planktonic community in southern coastal seawater of India. Surface seawater samples and biofilm assembled on three artificial surfaces over a period of 72 h of immersion in the intake area of a nuclear power plant at Kudankulam, India were collected. The structure of surface assemblages and plankton were unveiled by employing culture dependent, DGGE and NGS methods. In static condition, a collection of aerobic heterotrophic bacteria was screened in vitro for their ability to form potent biofilm. Proteobacteria preponderated the communities both in seawater and natural biofilm and Gammaproteobacteria accounted for >85% in the latter. Vibrionaceae, Alteromonadaceae and Pseudoalteromonadaceae dominated the biofilm community and constituted for 41, 25 and 8%, respectively. In contrast to other studies that showed Rhodobacteraceae family of Alphaproteobacteria as predominant component, we found Vibrionaceae of Gammaproteobacteria as dominant group in early stage of biofilm formation. Both DGGE and NGS data indicated that the attached community is noticeably distinct from those suspended in water column and form the basis for the proposed hypothesis of species sorting theory, that is, the local environmental conditions influence bacterial community assembly. Collectively, the data are testament for species sorting process that occur during initial assembly of bacterial community in marine environment and shed light on the structure of marine bacterial biofilm development. The outcome of the present study is of immense importance for designing long-term, efficient and appropriate strategies to control the biofouling phenomenon.},
}
@article {pmid30797019,
year = {2019},
author = {Hadpanus, P and Permsirivisarn, P and Roytrakul, S and Tungpradabkul, S},
title = {Biomarker discovery in the biofilm-forming process of Burkholderia pseudomallei by mass-spectrometry.},
journal = {Journal of microbiological methods},
volume = {159},
number = {},
pages = {26-33},
doi = {10.1016/j.mimet.2019.02.011},
pmid = {30797019},
issn = {1872-8359},
abstract = {A serious human infectious disease called Melioidosis is a result of Burkholderia pseudomallei infection. Treatment for infected individuals is difficult due to a wide range of ineffective antibiotics including a high level of antibiotic tolerance which has been known to be caused by biofilm production. However, biofilm forming processes of this bacterium are not well documented despite multiple-methodologies being applied. In this study, we utilized a proteomics strategy called whole cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (whole cell MALDI-TOF MS) to discover a potential biomarker relating biofilm forming in B. pseudomallei. The results presented a novel specific type of enzyme amylo-alpha-1, 6-glucosidase, which was demonstrated by a higher level of gene expression during the biofilm development. Our results also suggested a list of candidate markers that might be involved in this scenario. Eventually, this knowledge may expand valuable data to the biofilm study that may increase effective treatments for people infected with B. pseudomallei and possibly other antibiotic tolerant bacteria.},
}
@article {pmid30796889,
year = {2019},
author = {Dong, G and Li, J and Chen, L and Bi, W and Zhang, X and Liu, H and Zhi, X and Zhou, T and Cao, J},
title = {Effects of sub-minimum inhibitory concentrations of ciprofloxacin on biofilm formation and virulence factors of Escherichia coli.},
journal = {The Brazilian journal of infectious diseases : an official publication of the Brazilian Society of Infectious Diseases},
volume = {23},
number = {1},
pages = {15-21},
doi = {10.1016/j.bjid.2019.01.004},
pmid = {30796889},
issn = {1678-4391},
abstract = {OBJECTIVE: To evaluate the influence of sub-minimum inhibitory concentrations (MICs) of ciprofloxacin (CIP) on biofilm formation and virulence factors of Escherichia coli clinical isolates.<br><br>METHODS: Sub-MICs of CIP were determined using growth curve experiments. The biofilm-forming capacity of E. coli clinical isolates and E. coli ATCC 25922 treated or untreated with sub-MICs of CIP was assessed using a crystal violet staining assay. The biofilm structure of E. coli isolate was assessed with scanning electron microscopy (SEM). The expression levels of the virulence genes fim, usp, and iron and the biofilm formation genes of the pgaABCD locus were measured using quantification RT-PCR (qRT-PCR) in E. coli isolates and E. coli ATCC 25922.<br><br>RESULTS: Based on our results, the sub-MICs of CIP were 1/4 MICs. Sub-MICs of CIP significantly inhibited biofilm formation of E. coli clinical isolates and E. coli ATCC 25922 (p<0.01). SEM analyses indicated that the biofilm structure of the E. coli changed significantly after treatment with sub-MICs of CIP. Expression levels of the virulence genes fim, usp, and iron and the biofilm formation genes of the pgaABCD locus were also suppressed.<br><br>CONCLUSIONS: The results revealed that treatment with sub-MICs of CIP for 24h inhibited biofilm formation and reduced the expression of virulence genes and biofilm formation genes in E. coli.},
}
@article {pmid30796331,
year = {2019},
author = {Craft, KM and Townsend, SD},
title = {1-Amino-2'-fucosyllactose inhibits biofilm formation by Streptococcus agalactiae.},
journal = {The Journal of antibiotics},
volume = {},
number = {},
pages = {},
doi = {10.1038/s41429-019-0151-6},
pmid = {30796331},
issn = {0021-8820},
support = {T32 GM065086//U.S. Department of Health &amp; Human Services | NIH | National Institute of General Medical Sciences (NIGMS)/ ; },
abstract = {2'-Fucosyllactose (2'-FL) is a ubiquitous oligosaccharide in human milk. Importantly, this carbohydrate promotes the growth of several strains of Bifidobacteria, a class of beneficial gut commensal, and inhibits epithelial binding of pathogens. In light of these protective effects, we elected to evaluate the potential of 2'-FL to serve as an antibacterial agent against Group B Streptococcus (GBS). While 2'-FL was devoid of any substantial antimicrobial or antibiofilm activity, conversion of 2'-FL to its reducing end β-amine provided a novel antibiofilm compound.},
}
@article {pmid30796312,
year = {2019},
author = {Tan, A and Li, WS and Verderosa, AD and Blakeway, LV and D Mubaiwa, T and Totsika, M and Seib, KL},
title = {Moraxella catarrhalis NucM is an entry nuclease involved in extracellular DNA and RNA degradation, cell competence and biofilm scaffolding.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {2579},
doi = {10.1038/s41598-019-39374-0},
pmid = {30796312},
issn = {2045-2322},
abstract = {Moraxella catarrhalis is a host-adapted bacterial pathogen that causes otitis media and exacerbations of chronic obstructive pulmonary disease. This study characterises the conserved M. catarrhalis extracellular nuclease, a member of the ββα metal finger family of nucleases, that we have named NucM. NucM shares conserved sequence motifs from the ββα nuclease family, including the DRGH catalytic core and Mg2+ co-ordination site, but otherwise shares little primary sequence identity with other family members, such as the Serratia Nuc and pneumococcal EndA nucleases. NucM is secreted from the cell and digests linear and circular nucleic acid. However, it appears that a proportion of NucM is also associated with the cell membrane and acts as an entry nuclease, facilitating transformation of M. catarrhalis cells. This is the first example of a ββα nuclease in a Gram negative bacteria that acts as an entry nuclease. In addition to its role in competence, NucM affects cell aggregation and biofilm formation by M. catarrhalis, with ΔnucM mutants having increased biofilm biomass. NucM is likely to increase the ability of cells to survive and persist in vivo, increasing the virulence of M. catarrhalis and potentially affecting the behaviour of other pathogens that co-colonise the otorhinolaryngological niche.},
}
@article {pmid30794235,
year = {2019},
author = {Stinner, DJ},
title = {CORR Insights®: Does Suture Type Influence Bacterial Retention and Biofilm Formation After Irrigation in a Mouse Model?.},
journal = {Clinical orthopaedics and related research},
volume = {477},
number = {1},
pages = {127-129},
doi = {10.1097/CORR.0000000000000466},
pmid = {30794235},
issn = {1528-1132},
}
@article {pmid30794234,
year = {2019},
author = {Markel, DC and Bergum, C and Wu, B and Bou-Akl, T and Ren, W},
title = {Does Suture Type Influence Bacterial Retention and Biofilm Formation After Irrigation in a Mouse Model?.},
journal = {Clinical orthopaedics and related research},
volume = {477},
number = {1},
pages = {116-126},
doi = {10.1097/CORR.0000000000000391},
pmid = {30794234},
issn = {1528-1132},
abstract = {BACKGROUND: Irrigation and débridement are frequently utilized in the management of surgical infections, but even with aggressive débridement, it is difficult to remove all the suture material from the tissues and retained suture material may harbor bacteria and/or biofilm. The degree to which barbed or braided sutures may differentially influence the risk of infection has not been defined in a well-controlled animal model.<br><br>QUESTIONS/PURPOSES: We compared braided and barbed monofilament sutures after irrigation of an infected mouse air pouch model to determine whether the suture type influenced the effectiveness of the irrigation. After irrigation of infected pouches, sutures were compared for (1) bacterial adherence and bacterial retention; (2) qualitative and quantitative pouch thickness and cellular density; and (3) quantitative biofilm formation.<br><br>METHODS: Soft tissue air pouches were created on the backs of 60 female, mature 10-week-old BALB/cJ mice by sequentially introducing air into the subcutaneous tissue and allowing the pouch to mature. The pouches were inoculated with Staphylococcus aureus and braided or barbed monofilament sutures were implanted. Pouch irrigation was performed Day 7 after suture implantation. Suture segments were collected before and after irrigation. After euthanasia on Day 14, pouch tissues with residual suture segments were collected for analysis: microbiologic analysis done using optical density as a measure of the concentration of bacteria in the culture (the larger concentration indicates higher number of bacteria) and histologic evaluation of the pouch tissues were semiquantitative, whereas environmental scanning electron microscopy (ESEM) and confocal analyses of the biofilm and bacteria on the sutures were qualitative.<br><br>RESULTS: Histologic evaluation of pouch tissue showed all groups had inflammatory responses. Quantitatively microbiology showed no difference in bacterial number calculated from the optical density (OD) values between the two suture materials at any time point in the irrigation group. In the no-irrigation group, for the Day 7 time point, mean (± SD) OD was greater in the barbed than the OD in the braided sutures (0.52 ± 0.12 versus 0.37 ± 0.16, mean difference 0.43 [95% confidence interval, 0.08-0.13]; p = 0.007). Qualitatively, ESEM showed more bacterial retention by braided sutures before and after irrigation. Confocal imaging of the sutures demonstrated penetration of biofilm into the interstices of braided sutures and less adhesion in barbed monofilament sutures. The quantification of the biomass showed no differences between groups at all time points (before-irrigation biomass was 11.2 ± 9.3 for braided versus 5.2 ± 4.7 for barbed sutures, p = 0.196; and after-irrigation biomass was 7.2 ± 7.5 for braided versus 3.3 ± 4.3 for barbed suture, p = 0.259).<br><br>CONCLUSIONS: All sutures can retain bacteria and biofilm, but it is rarely possible to remove all suture material at the time of irrigation to treat infection. After an irrigation procedure, qualitatively braided sutures appeared to harbor more bacteria and to retain more biofilm than barbed monofilaments.<br><br>CLINICAL RELEVANCE: When saline irrigation was used to simulate infection treatment in an infected mouse air pouch model, bacteria/biofilm was not completely eliminated from either braided or barbed monofilament sutures. The irrigation appeared to clear more bacteria and biofilm from the monofilament despite having barbs. Unfortunately, current technologies do not allow direct quantitative comparisons of biofilm retention. Clinicians should be aware that in the face of infection, any retained sutures may harbor bacteria despite irrigation.},
}
@article {pmid30794029,
year = {2019},
author = {Mitra, S and Chayani, N and Mohapatra, D and Barik, MR and Sharma, S and Basu, S},
title = {High Prevalence of Biofilm-Forming MRSA in the Conjunctival Flora in Chronic Dacryocystitis.},
journal = {Seminars in ophthalmology},
volume = {34},
number = {2},
pages = {74-79},
doi = {10.1080/08820538.2019.1578382},
pmid = {30794029},
issn = {1744-5205},
mesh = {Anti-Bacterial Agents/therapeutic use ; *Biofilms ; Case-Control Studies ; Chronic Disease ; Conjunctiva/*microbiology ; DNA, Bacterial/*genetics ; Dacryocystitis/drug therapy/*epidemiology/microbiology ; Eye Infections, Bacterial/*epidemiology/microbiology ; Follow-Up Studies ; Humans ; India/epidemiology ; Methicillin-Resistant Staphylococcus aureus/drug effects/*genetics/isolation &amp; purification ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Prevalence ; Prospective Studies ; Staphylococcal Infections/drug therapy/*epidemiology/microbiology ; },
abstract = {OBJECTIVES: To report the microbiological spectrum of conjunctival flora and prevalence of biofilm-forming Methicillin-resistant Staphylococcus aureus (MRSA) in conjunctival flora in chronic dacryocystitis.<br><br>DESIGN: Prospective, case-control study.<br><br>METHODS: We included patients with unilateral chronic dacryocystitis, and their unaffected eyes as control. Microbiological profile and antibiotic susceptibility of the isolates was determined by standard microbiological procedures. S. aureus isolates were further evaluated for Methicillin resistance by Oxacillin resistance screening agar method and mecA polymerase chain reaction (PCR) and for biofilm synthesis by Congo red agar method, Microtitre plate (MTP) assay, and ica A and ica D PCR.<br><br>RESULTS: We found 95 patients with unilateral chronic dacryocystitis. Aerobic Gram-positive isolates (74.2%, n = 72) were more than Gram-negative (25.7%, n = 25) or anaerobic isolates (20.5%, n = 25). S. aureus was most common (46.4%, n = 45), followed by Pseudomonas aeruginosa (10.3%, n = 10). Gram-positive isolates showed highest sensitivity to Linezolid (100%) and higher generation fluoroquinolones. Gram-negative isolates showed good sensitivity (>90%) to all tested antibiotics. S. aureus isolates showed MRSA prevalence as 93.5% and 96.9% by Oxacillin resistance screening agar method and mecA PCR, respectively. Biofilm formation was found in 71.8% MRSA isolates by MTP assay and 58.1% MRSA isolates were resistant to ≥3 classes of antibiotics.<br><br>CONCLUSIONS: Gram-positive organisms, specifically S. aureus, are the major etiological agent in chronic dacryocystitis. There is high prevalence of MRSA in these isolates and concurrent biofilm formation.},
}
@article {pmid30792088,
year = {2019},
author = {Vyas, N and Manmi, K and Wang, Q and Jadhav, AJ and Barigou, M and Sammons, RL and Kuehne, SA and Walmsley, AD},
title = {Which Parameters Affect Biofilm Removal with Acoustic Cavitation? A Review.},
journal = {Ultrasound in medicine &amp; biology},
volume = {45},
number = {5},
pages = {1044-1055},
doi = {10.1016/j.ultrasmedbio.2019.01.002},
pmid = {30792088},
issn = {1879-291X},
abstract = {Bacterial biofilms are a cause of contamination in a wide range of medical and biological areas. Ultrasound is a mechanical energy that can remove these biofilms using cavitation and acoustic streaming, which generate shear forces to disrupt biofilm from a surface. The aim of this narrative review is to investigate the literature on the mechanical removal of biofilm using acoustic cavitation to identify the different operating parameters affecting its removal using this method. The properties of the liquid and the properties of the ultrasound have a large impact on the type of cavitation generated. These include gas content, temperature, surface tension, frequency of ultrasound and acoustic pressure. For many of these parameters, more research is required to understand their mechanisms in the area of ultrasonic biofilm removal, and further research will help to optimise this method for effective removal of biofilms from different surfaces.},
}
@article {pmid30791514,
year = {2019},
author = {Wallis, JK and Krömker, V and Paduch, JH},
title = {Biofilm Challenge: Lactic Acid Bacteria Isolated from Bovine Udders versus Staphylococci.},
journal = {Foods (Basel, Switzerland)},
volume = {8},
number = {2},
pages = {},
doi = {10.3390/foods8020079},
pmid = {30791514},
issn = {2304-8158},
support = {Project 31833//Deutsche Bundesstiftung Umwelt/ ; 1803//Steinbeis Research Center Milk Science/ ; },
abstract = {Mastitis poses a considerable threat to productivity and to animal welfare on modern dairy farms. However, the common way of antibiotic treatment does not always lead to a cure. Unsuccessful cures can, among other reasons, occur due to biofilm formation of the causative agent. This has attracted interest from researchers to introduce promising alternative therapeutic approaches, such as the use of beneficial lactic acid bacteria (LAB). In fact, using LAB for treating mastitis probably requires the formation of a beneficial biofilm by the probiotic bacteria. The present study investigated the ability of five LAB strains, selected on the basis of results from previous studies, to remove and to replace pathogenic biofilms in vitro. For this purpose, Staphylococcus (S.) aureus ATCC 12,600 and two strains-S. xylosus (35/07) and S. epidermidis (575/08)-belonging to the group of coagulase negative staphylococci (CNS) were allowed to form biofilms in a 96-well plate. Subsequently, the LAB were added to the well. The biofilm challenge was evaluated by scraping off and suspending the biofilm cells, followed by a plate count of serial dilutions using selective media. All the LAB strains successfully removed the staphylococcal biofilms. However, only Lactobacillus (L.) rhamnosus ATCC 7469 and L. plantarum 2/37 formed biofilms of their own to replace the pathogenic ones.},
}
@article {pmid30787924,
year = {2019},
author = {Sivakumar, K and Scarascia, G and Zaouri, N and Wang, T and Kaksonen, AH and Hong, PY},
title = {Salinity-Mediated Increment in Sulfate Reduction, Biofilm Formation, and Quorum Sensing: A Potential Connection Between Quorum Sensing and Sulfate Reduction?.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {188},
doi = {10.3389/fmicb.2019.00188},
pmid = {30787924},
issn = {1664-302X},
abstract = {Biocorrosion in marine environment is often associated with biofilms of sulfate reducing bacteria (SRB). However, not much information is available on the mechanism underlying exacerbated rates of SRB-mediated biocorrosion under saline conditions. Using Desulfovibrio (D.) vulgaris and Desulfobacterium (Db.) corrodens as model SRBs, the enhancement effects of salinity on sulfate reduction, N-acyl homoserine lactone (AHL) production and biofilm formation by SRBs were demonstrated. Under saline conditions, D. vulgaris and Db. corrodens exhibited significantly higher specific sulfate reduction and specific AHL production rates as well as elevated rates of biofilm formation compared to freshwater medium. Salinity-induced enhancement traits were also confirmed at transcript level through reverse transcription quantitative polymerase chain reaction (RT-qPCR) approach, which showed salinity-influenced increase in the expression of genes associated with carbon metabolism, sulfate reduction, biofilm formation and histidine kinase signal transduction. In addition, by deploying quorum sensing (QS) inhibitors, a potential connection between sulfate reduction and AHL production under saline conditions was demonstrated, which is most significant during early stages of sulfate metabolism. The findings collectively revealed the interconnection between QS, sulfate reduction and biofilm formation among SRBs, and implied the potential of deploying quorum quenching approaches to control SRB-based biocorrosion in saline conditions.},
}
@article {pmid30786799,
year = {2019},
author = {Yong, YY and Dykes, GA and Choo, WS},
title = {Biofilm formation by staphylococci in health-related environments and recent reports on their control using natural compounds.},
journal = {Critical reviews in microbiology},
volume = {},
number = {},
pages = {1-22},
doi = {10.1080/1040841X.2019.1573802},
pmid = {30786799},
issn = {1549-7828},
abstract = {Staphylococci are Gram-positive bacteria that are ubiquitous in the environment and able to form biofilms on a range of surfaces. They have been associated with a range of human health issues such as medical device-related infection, localized skin infection, or direct infection caused by toxin production. The extracellular material produced by these bacteria resists antibiotics and host defence mechanism which complicates the treatment process. The commonly reported Staphylococcus species are Staphylococcus aureus and S. epidermidis as they inhabit human bodies. However, the emergence of other staphylococci, such as S. haemolyticus, S. lugdunensis, S. saprophyticus, S. capitis, S. saccharolyticus, S. warneri, S. cohnii, and S. hominis, is also of concern and they have been associated with biofilm formation. This review critically assesses recent cases on the biofilm formation by S. aureus, S. epidermidis, and other staphylococci reported in health-related environments. The control of biofilm formation by staphylococci using natural compounds is specifically discussed as they represent potential anti-biofilm agents which may reduce the burden of antibiotic resistance.},
}
@article {pmid30785531,
year = {2019},
author = {Fraiha, RO and Pereira, APR and Brito, EDCA and Borges, CL and Parente, AFA and Perdomo, RT and Macedo, MLR and Weber, SS},
title = {Stress conditions in the host induce persister cells and influence biofilm formation by Staphylococcus epidermidis RP62A.},
journal = {Revista da Sociedade Brasileira de Medicina Tropical},
volume = {52},
number = {},
pages = {e20180001},
doi = {10.1590/0037-8682-0001-2018},
pmid = {30785531},
issn = {1678-9849},
mesh = {Biofilms/*growth &amp; development ; Biological Assay ; Culture Media/*pharmacology ; Host Microbial Interactions/drug effects/*physiology ; Humans ; Staphylococcus epidermidis/drug effects/pathogenicity/*physiology ; Stress, Physiological ; Virulence/drug effects/*physiology ; },
abstract = {INTRODUCTION: Studies have demonstrated that pathogens react to the harsh conditions in human tissues by inducing mechanisms that promote survival.<br><br>METHODS: Persistence and biofilm-forming ability were evaluated during stress conditions that mimic those in the host.<br><br>RESULTS: Carbon-source availability had a positive effect on Staphylococcus epidermidis RP62A adhesion during hypoxia, accompanied by a decrease in pH. In contrast, iron limitation led to decreased surface-adherent biomass, accompanied by an increase medium acidification and lactate levels. Interestingly, iron starvation and hypoxia induced persister cells in planktonic culture.<br><br>CONCLUSIONS: These findings highlight the role of host stress in the virulence of S. epidermidis.},
}
@article {pmid30785306,
year = {2019},
author = {Lou, Z and Letsididi, KS and Yu, F and Pei, Z and Wang, H and Letsididi, R},
title = {Inhibitive Effect of Eugenol and Its Nanoemulsion on Quorum Sensing-Mediated Virulence Factors and Biofilm Formation by Pseudomonas aeruginosa.},
journal = {Journal of food protection},
volume = {82},
number = {3},
pages = {379-389},
doi = {10.4315/0362-028X.JFP-18-196},
pmid = {30785306},
issn = {1944-9097},
abstract = {The aim of the present study was to evaluate the quorum sensing (QS) inhibition potential of eugenol and eugenol nanoemulsion against QS-dependent virulence factor production and gene expression, as well as biofilm formation in Pseudomonas aeruginosa. In the current study, eugenol nanoemulsion at a sub-MIC of 0.2 mg/mL specifically inhibited about 50% of the QS-mediated violacein production in Chromobacterium violaceum, as well as the production of N-(3-oxododecanoyl)-l-homoserine lactone (3-oxo-C12-HSL) and C4-HSL N-acyl homoserine lactone signal molecules, pyocyanin, and swarming motility in P. aeruginosa. The inhibitive effect of eugenol and its nanoemulsion on the expression of the QS synthase genes was concentration dependent, displaying 65 and 52% expression level for lasI, respectively, and 61 and 45% expression level for rhlI, respectively, at a concentration of 0.2 mg/mL. In addition, the inhibitive effect of eugenol and its nanoemulsion on the expression of the rhlA gene responsible for the production of rhamnolipid was also concentration dependent, displaying 65 and 51% expression level for the rhlA gene, respectively, at a concentration of 0.2 mg/mL. Eugenol and its nanoemulsion also displayed 36 and 63% respective inhibition of biofilm formation by P. aeruginosa at the 0.2 mg/mL concentration. Therefore, the nanoemulsion could be used as a novel QS-based antibacterial and antibiofilm agent for the control of harmful bacteria.},
}
@article {pmid30785206,
year = {2019},
author = {Vollaro, A and Catania, MR and Iesce, MR and Sferruzza, R and D'Abrosca, B and Donnarumma, G and De Filippis, A and Cermola, F and DellaGreca, M and Buommino, E},
title = {Antimicrobial and anti-biofilm properties of novel synthetic lignan-like compounds.},
journal = {The new microbiologica},
volume = {42},
number = {1},
pages = {21-28},
pmid = {30785206},
issn = {1121-7138},
abstract = {Antibiotic resistance and biofilm tolerance are among the principal factors involved in the persistence of chronic infections. The need for new antimicrobials is an ever-increasing challenge in clinical environments and in the control of global health. Arylfurans form a set of structures that have been identified in many natural products, e.g. lignans. Lignans are a sub-group of non-flavonoid polyphenols that play an active role in plants' defense against bacteria and fungi infections. The aim of this study was to identify novel synthetic arylfurans and lignan-like arylbenzylfurans exhibiting antimicrobial properties. The molecules synthetized were tested against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and S. epidermidis. We found that among tested compounds, arylbenzylfuran 11 was active against S. aureus and S. epidermidis with an MIC of 4 μg ml-1. Compound 11 was also active on methicillin-resistant S. aureus and S. epidermidis. By confocal laser scanning microscopy, we showed that 32 μg ml-1 of compound 11 was able to induce a significant reduction in S. aureus and S. epidermidis biofilms viability. Finally, we demonstrated that compound 11 was not cytotoxic on HaCat cells up to 128 μg ml-1. This work shows the antimicrobial and anti-biofilm potential of a synthetic lignan-like furan.},
}
@article {pmid30784999,
year = {2019},
author = {Hu, Q and Zhou, N and Rene, ER and Wu, D and Sun, D and Qiu, B},
title = {Stimulation of anaerobic biofilm development in the presence of low concentrations of toxic aromatic pollutants.},
journal = {Bioresource technology},
volume = {281},
number = {},
pages = {26-30},
doi = {10.1016/j.biortech.2019.02.076},
pmid = {30784999},
issn = {1873-2976},
abstract = {The main aim of this work was to stimulate biofilm formation in the presence of wastewater containing aromatic compounds with different toxicities (EC50). The results indicated that wastewater with an EC50 value >85% accelerates the attachment of bacteria onto the bio-carriers because the toxic wastewater stimulates the production of extracellular polymeric substances (EPS) from the seed sludge. In order to understand the role of EPS on biofilm development, experiments were conducted using the seed sludge, from which the soluble, loosely bound, and tightly bound EPS were removed. The soluble EPS fraction was determined to be crucial for biofilm development. Firmicutes bacterium and Clostridium chromoreductans survived and were enriched in the formed biofilms in our study, which can resist toxic aromatics.},
}
@article {pmid30783456,
year = {2019},
author = {Xu, Y and Wang, J and Hao, Z and Wang, S and Liang, C},
title = {Biodegradable ciprofloxacin-incorporated waterborne polyurethane polymers prevent bacterial biofilm formation in vitro.},
journal = {Experimental and therapeutic medicine},
volume = {17},
number = {3},
pages = {1831-1836},
doi = {10.3892/etm.2018.7113},
pmid = {30783456},
issn = {1792-0981},
abstract = {The aim of the present study was to explore whether ciprofloxacin-incorporated waterborne polyurethane (WBPU) polymers have the capacity to inhibit bacterial biofilm formation in vitro. WBPU polymers were incorporated with ciprofloxacin and were cultured with Escherichia coli (E. coli) or Staphylococcus aureus (S. aureus) in media for 2, 4 or 7 days. In another experiment, the WBPU membranes were cultured with Proteus mirabilis (P. mirabilis) in artificial urine for 2, 4 or 7 days. Colony counting, scanning electron microscopy and fluorescence confocal microscopy were utilized to examine bacterial biofilms on the surfaces of membranes. The membranes were further co-cultured with P. mirabilis in a simple model of an artificial catheterized bladder in order to evaluate their ability to control encrustation. The WBPU films with ciprofloxacin effectively inhibited bacterial biofilm formation in the culture medium and in artificial urine. In addition, in artificial urine, the films with ciprofloxacin reduced catheter obstruction. In conclusion, ciprofloxacin-incorporated WBPU polymers are able to effectively inhibit bacterial biofilm formation in vitro.},
}
@article {pmid30782633,
year = {2019},
author = {Nepper, JF and Lin, YC and Weibel, DB},
title = {Rcs Phosphorelay Activation in Cardiolipin-Deficient Escherichia coli Reduces Biofilm Formation.},
journal = {Journal of bacteriology},
volume = {201},
number = {9},
pages = {},
doi = {10.1128/JB.00804-18},
pmid = {30782633},
issn = {1098-5530},
abstract = {Biofilm formation is a complex process that requires a number of transcriptional, proteomic, and physiological changes to enable bacterial survival. The lipid membrane presents a barrier to communication between the machinery within bacteria and the physical and chemical features of their extracellular environment, and yet little is known about how the membrane influences biofilm development. We found that depleting the anionic phospholipid cardiolipin reduces biofilm formation in Escherichia coli cells by as much as 50%. The absence of cardiolipin activates the regulation of colanic acid synthesis (Rcs) envelope stress response, which represses the production of flagella, disrupts initial biofilm attachment, and reduces biofilm growth. We demonstrate that a reduction in the concentration of cardiolipin impairs translocation of proteins across the inner membrane, which we hypothesize activates the Rcs pathway through the outer membrane lipoprotein RcsF. Our study demonstrates a molecular connection between the composition of membrane phospholipids and biofilm formation in E. coli and suggests that altering lipid biosynthesis may be a viable approach for altering biofilm formation and possibly other multicellular phenotypes related to bacterial adaptation and survival.IMPORTANCE There is a growing interest in the role of lipid membrane composition in the physiology and adaptation of bacteria. We demonstrate that a reduction in the anionic phospholipid cardiolipin impairs biofilm formation in Escherichia coli cells. Depleting cardiolipin reduced protein translocation across the inner membrane and activated the Rcs envelope stress response. Consequently, cardiolipin depletion produced cells lacking assembled flagella, which impacted their ability to attach to surfaces and seed the earliest stage in biofilm formation. This study provides empirical evidence for the role of anionic phospholipid homeostasis in protein translocation and its effect on biofilm development and highlights modulation of the membrane composition as a potential method of altering bacterial phenotypes related to adaptation and survival.},
}
@article {pmid30782630,
year = {2019},
author = {Rotman, ER and Bultman, KM and Brooks, JF and Gyllborg, MC and Burgos, HL and Wollenberg, MS and Mandel, MJ},
title = {Natural Strain Variation Reveals Diverse Biofilm Regulation in Squid-Colonizing Vibrio fischeri.},
journal = {Journal of bacteriology},
volume = {201},
number = {9},
pages = {},
doi = {10.1128/JB.00033-19},
pmid = {30782630},
issn = {1098-5530},
support = {R35 GM119627/GM/NIGMS NIH HHS/United States ; },
abstract = {The mutualistic symbiont Vibrio fischeri builds a symbiotic biofilm during colonization of squid hosts. Regulation of the exopolysaccharide component, termed Syp, has been examined in strain ES114, where production is controlled by a phosphorelay that includes the inner membrane hybrid histidine kinase RscS. Most strains that lack RscS or encode divergent RscS proteins cannot colonize a squid host unless RscS from a squid symbiont is heterologously expressed. In this study, we examine V. fischeri isolates worldwide to understand the landscape of biofilm regulation during beneficial colonization. We provide a detailed study of three distinct evolutionary groups of V. fischeri and find that while the RscS-Syp biofilm pathway is required in one of the groups, two other groups of squid symbionts require Syp independent of RscS. Mediterranean squid symbionts, including V. fischeri SR5, colonize without an RscS homolog encoded by their genome. Additionally, group A V. fischeri strains, which form a tightly related clade of Hawaii isolates, have a frameshift in rscS and do not require the gene for squid colonization or competitive fitness. These same strains have a frameshift in sypE, and we provide evidence that this group A sypE allele leads to an upregulation in biofilm activity. Thus, this work describes the central importance of Syp biofilm in colonization of diverse isolates and demonstrates that significant evolutionary transitions correspond to regulatory changes in the syp pathway.IMPORTANCE Biofilms are surface-associated, matrix-encased bacterial aggregates that exhibit enhanced protection to antimicrobial agents. Previous work has established the importance of biofilm formation by a strain of luminous Vibrio fischeri bacteria as the bacteria colonize their host, the Hawaiian bobtail squid. In this study, expansion of this work to many natural isolates revealed that biofilm genes are universally required, yet there has been a shuffling of the regulators of those genes. This work provides evidence that even when bacterial behaviors are conserved, dynamic regulation of those behaviors can underlie evolution of the host colonization phenotype. Furthermore, this work emphasizes the importance of investigating natural diversity as we seek to understand molecular mechanisms in bacteria.},
}
@article {pmid30782552,
year = {2019},
author = {Laureni, M and Weissbrodt, DG and Villez, K and Robin, O and de Jonge, N and Rosenthal, A and Wells, G and Nielsen, JL and Morgenroth, E and Joss, A},
title = {Biomass segregation between biofilm and flocs improves the control of nitrite-oxidizing bacteria in mainstream partial nitritation and anammox processes.},
journal = {Water research},
volume = {154},
number = {},
pages = {104-116},
doi = {10.1016/j.watres.2018.12.051},
pmid = {30782552},
issn = {1879-2448},
abstract = {The control of nitrite-oxidizing bacteria (NOB) challenges the implementation of partial nitritation and anammox (PN/A) processes under mainstream conditions. The aim of the present study was to understand how operating conditions impact microbial competition and the control of NOB in hybrid PN/A systems, where biofilm and flocs coexist. A hybrid PN/A moving-bed biofilm reactor (MBBR; also referred to as integrated fixed film activated sludge or IFAS) was operated at 15 °C on aerobically pre-treated municipal wastewater (23 mgNH4-N L-1). Ammonium-oxidizing bacteria (AOB) and NOB were enriched primarily in the flocs, and anammox bacteria (AMX) in the biofilm. After decreasing the dissolved oxygen concentration (DO) from 1.2 to 0.17 mgO2 L-1 - with all other operating conditions unchanged - washout of NOB from the flocs was observed. The activity of the minor NOB fraction remaining in the biofilm was suppressed at low DO. As a result, low effluent NO3- concentrations (0.5 mgN L-1) were consistently achieved at aerobic nitrogen removal rates (80 mgN L-1 d-1) comparable to those of conventional treatment plants. A simple dynamic mathematical model, assuming perfect biomass segregation with AOB and NOB in the flocs and AMX in the biofilm, was able to qualitatively reproduce the selective washout of NOB from the flocs in response to the decrease in DO-setpoint. Similarly, numerical simulations indicated that flocs removal is an effective operational strategy to achieve the selective washout of NOB. The direct competition for NO2- between NOB and AMX - the latter retained in the biofilm and acting as a &quot;NO2-sink&quot; - was identified by the model as key mechanism leading to a difference in the actual growth rates of AOB and NOB (i.e., μNOB < μAOB in flocs) and allowing for the selective NOB washout over a broad range of simulated sludge retention times (SRT = 6.8-24.5 d). Experimental results and model predictions demonstrate the increased operational flexibility, in terms of variables that can be easily controlled by operators, offered by hybrid systems as compared to solely biofilm systems for the control of NOB in mainstream PN/A applications.},
}
@article {pmid30779754,
year = {2019},
author = {Zhao, M and Li, W and Liu, K and Li, H and Lan, X},
title = {C4-HSL aptamers for blocking qurom sensing and inhibiting biofilm formation in Pseudomonas aeruginosa and its structure prediction and analysis.},
journal = {PloS one},
volume = {14},
number = {2},
pages = {e0212041},
doi = {10.1371/journal.pone.0212041},
pmid = {30779754},
issn = {1932-6203},
abstract = {This study aimed to screen DNA aptamers against the signal molecule C4-HSL of the rhl system for the inhibition of biofilm formation of Pseudomonas aeruginosa using an improved systematic evolution of ligand by exponential enrichment (SELEX) method based on a structure-switching fluorescent activating bead. The aptamers against the C4-HSL with a high affinity and specifity were successfully obtained and evaluated in real-time by this method. Results of biofilm inhibition experiments in vitro showed that the biofilm formation of P. aeruginosa was efficiently reduced to about 1/3 by the aptamers compared with that of the groups without the aptamers. Independent secondary structure simulation and computer-aided tertiary structure prediction (3dRNA) showed that the aptamers contained a highly conserved Y-shaped structural unit. Therefore, this study benefits the search for new methods for the detection and treatment of P. aeruginosa biofilm formation.},
}
@article {pmid30779315,
year = {2019},
author = {Bachtiar, BM and Srisawat, C and Bachtiar, EW},
title = {RNA aptamers selected against yeast cells inhibit Candida albicans biofilm formation in vitro.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e812},
doi = {10.1002/mbo3.812},
pmid = {30779315},
issn = {2045-8827},
abstract = {Aptamers that bind live bacterial cells have been widely investigated, but their potential to inhibit Candida albicans biofilm formation needs to be further explored. The aims of this study were to evaluate the binding of C. albicans to RNA aptamers and to examine the potential of aptamers to inhibit C. albicans biofilm formation in vitro. In this study, RNA aptamers selected against yeast cells of C. albicans ATCC 10231 were developed using the systematic evolution of ligands by exponential enrichment (SELEX) technique. The binding affinity of the resulting aptamers was then determined by an aptamer-linked immobilized sorbent assay (ALISA), and a colorimetric (MTT) assay was used to measure the metabolic activity of Candida biofilms. After 11 rounds of SELEX, two candidate aptamers, Ca-apt-1 and Ca-apt-12, were identified. The Ca-apt-1 aptamer also recognized C. albicans isolated from clinical specimens but did not recognize other oral microorganisms (i.e., Streptococcus mutans and Saccharomyces cerevisiae). The ALISA results showed that the binding affinity of these aptamers was comparable to that of an anti-C. albicans monoclonal antibody. In addition, Ca-apt-1 could inhibit biofilm and hyphal formation of C. albicans in vitro, as demonstrated using biofilm assays. This study shows that RNA aptamers could potentially be used in diagnostic and therapeutic applications for C. albicans-related disease in the future.},
}
@article {pmid30776636,
year = {2019},
author = {Xu, G and Zheng, X and Lu, Y and Liu, G and Luo, H and Li, X and Zhang, R and Jin, S},
title = {Development of microbial community within the cathodic biofilm of single-chamber air-cathode microbial fuel cell.},
journal = {The Science of the total environment},
volume = {665},
number = {},
pages = {641-648},
doi = {10.1016/j.scitotenv.2019.02.175},
pmid = {30776636},
issn = {1879-1026},
mesh = {Bioelectric Energy Sources/*microbiology ; Biofilms/*growth &amp; development ; Electrodes ; Microbiota/*physiology ; },
abstract = {The aim of this study was to investigate the development of microbial community within the cathodic biofilm of single-chamber air-cathode microbial fuel cell (MFC). To analyze microbial community structures within cathodic biofilm, cathodic biofilm samples were stratified into three layers, i.e., the cathode-side layer (0-40 μm), the middle layer (40-80 μm), and the anolyte-side layer (80-120 μm). After four starting cycles (0-188 h), the maximum power densities of the MFC fed with 1 g/L acetate decreased from 1056 ± 110 to 410 ± 50 mW/m2 within 15 cycles (~30 d) of operation. The relative abundance of Pseudomonas gradually increased from 18.9% in the 1st cycle to 50.2% in the 4th cycle. After 15 cycles, the relative abundance of Pseudomonas became 53.8%, 16.4%, and 8.90% in the middle, anolyte-side, and cathode-side layers, respectively. The aerobic bacteria within the cathodic biofilm increased from 24% in the anodyte-side layer to 43% in the cathode-side layer. The relative abundance of Methanobrevibacter was 42.1% and 37.2% after 3 and 15 cycles, respectively. The bacterial community structures were similar among cycles 2, 3, and 4, but significantly different in the 15th cycle. The results from this study should be useful to understand the mechanism of the cathodic biofilm formation and to develop strategies to enhance performance of the MFC.},
}
@article {pmid30774968,
year = {2019},
author = {Vermilyea, DM and Ottenberg, GK and Davey, ME},
title = {Citrullination mediated by PPAD constrains biofilm formation in P. gingivalis strain 381.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {7},
doi = {10.1038/s41522-019-0081-x},
pmid = {30774968},
issn = {2055-5008},
support = {F31 DE027278/DE/NIDCR NIH HHS/United States ; R01 DE019117/DE/NIDCR NIH HHS/United States ; R01 DE024580/DE/NIDCR NIH HHS/United States ; T90 DE021990/DE/NIDCR NIH HHS/United States ; },
abstract = {Porphyromonas gingivalis is the only known human-associated prokaryote that produces a peptidylarginine deiminase (PPAD), a protein-modifying enzyme that is secreted along with a number of virulence factors via a type IX secretion system (T9SS). While the function of PPAD in P. gingivalis physiology is not clear, human peptidylarginine deiminases are known to convert positively charged arginine residues within proteins to neutral citrulline and, thereby, impact protein conformation and function. Here, we report that the lack of citrullination in a PPAD deletion mutant (Δ8820) enhances biofilm formation. More Δ8820 cells attached to the surface than the parent strain during the early stages of biofilm development and, ultimately, mature Δ8820 biofilms were comprised of significantly more cell-cell aggregates and extracellular matrix. Imaging by electron microscopy discovered that Δ8820 biofilm cells secrete copious amounts of protein aggregates. Furthermore, gingipain-derived adhesin proteins, which are also secreted by the T9SS were predicted by mass spectrometry to be citrullinated and citrullination of these targets by wild-type strain 381 in vitro was confirmed. Lastly, Δ8820 biofilms contained more gingipain-derived adhesin proteins and more gingipain activity than 381 biofilms. Overall, our findings support the model that citrullination of T9SS cargo proteins known to play a key role in colonization, such as gingipain-derived adhesin proteins, is an underlying mechanism that modulates P. gingivalis biofilm development.},
}
@article {pmid30773505,
year = {2019},
author = {Prasad, M and Obana, N and Sakai, K and Nagakubo, T and Miyazaki, S and Toyofuku, M and Fattaccioli, J and Nomura, N and Utada, AS},
title = {Point Mutations Lead to Increased Levels of c-di-GMP and Phenotypic Changes to the Colony Biofilm Morphology in Alcanivorax borkumensis SK2.},
journal = {Microbes and environments},
volume = {34},
number = {1},
pages = {104-107},
doi = {10.1264/jsme2.ME18151},
pmid = {30773505},
issn = {1347-4405},
mesh = {Alcanivoraceae/genetics/metabolism/*physiology ; Alkanes/metabolism ; Bacterial Proteins/*genetics/metabolism ; Biofilms/*growth &amp; development ; Cyclic GMP/*analogs &amp; derivatives/metabolism ; Gene Expression Regulation, Bacterial ; Genome, Bacterial/genetics ; Phenotype ; Point Mutation ; Polysaccharides, Bacterial/biosynthesis ; },
abstract = {Alcanivorax borkumensis is a ubiquitous marine bacterium that utilizes alkanes as a sole carbon source. We observed two phenotypes in the A. borkumensis SK2 type strain: rough (R) and smooth (S) types. The S type exhibited lower motility and higher polysaccharide production than the R type. Full genome sequencing revealed a mutation in the S type involved in cyclic-di-GMP production. The present results suggest that higher c-di-GMP levels in the S type control the biofilm forming behavior of this bacterium in a manner commensurate with other Gram-negative bacteria.},
}
@article {pmid30772604,
year = {2019},
author = {Cascioferro, S and Parrino, B and Petri, GL and Cusimano, MG and Schillaci, D and Di Sarno, V and Musella, S and Giovannetti, E and Cirrincione, G and Diana, P},
title = {2,6-Disubstituted imidazo[2,1-b][1,3,4]thiadiazole derivatives as potent staphylococcal biofilm inhibitors.},
journal = {European journal of medicinal chemistry},
volume = {167},
number = {},
pages = {200-210},
doi = {10.1016/j.ejmech.2019.02.007},
pmid = {30772604},
issn = {1768-3254},
mesh = {Anti-Bacterial Agents/*chemical synthesis/pharmacology ; Biofilms/*drug effects ; Gram-Negative Bacteria/drug effects/growth &amp; development/pathogenicity ; Gram-Positive Bacteria/drug effects/growth &amp; development/pathogenicity ; Indoles/chemical synthesis/pharmacology ; Staphylococcus/*drug effects/physiology ; Thiadiazoles/*chemical synthesis/*pharmacology ; Virulence/drug effects ; },
abstract = {A class of 36 new 2-(6-phenylimidazo[2,-1-b][1,3,4]thiadiazol-2-yl)-1H-indoles was efficiently synthesized and evaluated for their anti-biofilm properties against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 25923, S. aureus ATCC 6538 and Staphylococcus epidermidis ATCC 12228, and the Gram-negative strains Pseudomonas aeruginosa ATCC 15442 and Escherichia coli ATCC 25922. Many of these new compounds, were able to inhibit biofilm formation of the tested staphylococcal strains showing BIC50 lower than 10 μg/ml. In particular, derivatives 9c and 9h showed remarkable anti-biofilm activity against S. aureus ATCC 25923 with BIC50 values of 0.5 and 0.8 μg/ml, respectively, whereas compound 9aa was the most potent against S. aureus ATCC 6538, with a BIC50 of 0.3 μg/ml. Remarkably, these compounds showed effects in the early stages of the biofilm formation without affecting the mature biofilm of the same strains and the viability of the planktonic form. Their ability in counteracting a virulence factor (biofilm formation) without interfering with the bacterial growth in the free life form make them novel valuable anti-virulence agents.},
}
@article {pmid30771661,
year = {2019},
author = {Yang, Y and Choi, C and Xie, G and Park, JD and Ke, S and Yu, JS and Zhou, J and Lim, B},
title = {Electron transfer interpretation of the biofilm-coated anode of a microbial fuel cell and the cathode modification effects on its power.},
journal = {Bioelectrochemistry (Amsterdam, Netherlands)},
volume = {127},
number = {},
pages = {94-103},
doi = {10.1016/j.bioelechem.2019.02.004},
pmid = {30771661},
issn = {1878-562X},
mesh = {Acetates/metabolism ; Bioelectric Energy Sources/*microbiology ; Biofilms/growth &amp; development ; Carbon/chemistry ; Clostridium/enzymology/physiology ; Cytochromes c/metabolism ; Electricity ; Electrodes ; Electron Transport ; Flavin Mononucleotide/metabolism ; NAD/metabolism ; Oxidation-Reduction ; Porosity ; Proteobacteria/enzymology/physiology ; },
abstract = {Biofilm-coated electrodes and outer cell membrane-mimicked electrodes were examined to verify an extracellular electron transfer mechanism using Marcus theory for a donor-acceptor electron transfer. Redox couple-bound membrane electrodes were prepared by impregnating redox coenzymes into Nafion films on carbon cloth electrodes. The electron transfer was believed to occur sequentially from acetate to nicotinamide adenine dinucleotide (NAD), c-type cytochrome, flavin mononucleotide (FMN) (or riboflavin (RBF)) and the anode substrate. Excellent polarisation and power density characteristics were contributed by the modification of the cathode with a high-surface-area ordered mesoporous carbon or a hollow core-mesoporous shell carbon. The maximum power density of the microbial fuel cell (MFC) could be improved by a factor of two mainly due to the accelerated electron consumption by modifying the cathode surfaces within three-dimensionally interconnected mesoporous carbon particles, and the anode was coated with a mixed culture of anaerobic bacteria.},
}
@article {pmid30771288,
year = {2019},
author = {Perez-Lopez, MI and Mendez-Reina, R and Trier, S and Herrfurth, C and Feussner, I and Bernal, A and Forero-Shelton, M and Leidy, C},
title = {Variations in carotenoid content and acyl chain composition in exponential, stationary and biofilm states of Staphylococcus aureus, and their influence on membrane biophysical properties.},
journal = {Biochimica et biophysica acta. Biomembranes},
volume = {1861},
number = {5},
pages = {978-987},
doi = {10.1016/j.bbamem.2019.02.001},
pmid = {30771288},
issn = {1879-2642},
abstract = {Bacteria are often found in close association with surfaces, resulting in the formation of biofilms. In Staphylococcus aureus (S. aureus), biofilms are implicated in the resilience of chronic infections, presenting a serious clinical problem world-wide. Here, S. aureus biofilms are grown under flow within clinical catheters at 37 °C. The lipid composition and biophysical properties of lipid extracts from these biofilms are compared with those from exponential growth and stationary phase cells. Biofilms show a reduction in iso and anteiso branching compensated by an increase in saturated fatty acids compared to stationary phase. A drastic reduction in carotenoid levels is also observed during biofilm formation. Thermotropic measurements of Laurdan GP and DPH polarization, show a reduction of lipid packing at 37 °C for biofilms compared to stationary phase. We studied the effects of carotenoid content on DMPG and DPPG model membranes showing trends in thermotropic behavior consistent with those observed in bacterial isolates, indicating that carotenoids participate in modulating lipid packing. Additionally, bending elastic constant (kc) measurements using vesicle fluctuation analysis (VFA) show that the presence of carotenoids can increase membrane bending rigidity. The antimicrobial peptide Magainin H2 was less activity on liposomes composed of stationary phase compared to biofilms or exponential growth isolates. This study contributes to an understanding of how Staphylococcus aureus modulates the composition of its membrane lipids, and how those changes affect the biophysical properties of membranes, which in turn may play a role in its virulence and its resistance to different membrane-active antimicrobial agents.},
}
@article {pmid30770577,
year = {2019},
author = {Sweeney, E and Lovering, AM and Bowker, KE and MacGowan, AP and Nelson, SM},
title = {An in vitro biofilm model of Staphylococcus aureus infection of bone.},
journal = {Letters in applied microbiology},
volume = {68},
number = {4},
pages = {294-302},
doi = {10.1111/lam.13131},
pmid = {30770577},
issn = {1472-765X},
support = {//North Bristol NHS Trust/ ; },
abstract = {Chronic osteomyelitis is difficult to treat, with biofilm growth and the diffusion barrier to antibiotics presented by bone contributory factors. The aim of this study was to develop and evaluate an in vitro model of osteomyelitis. A bioluminescent strain of Staphylococcus aureus was grown in bone blocks made from bovine femur. Light output was insufficient for detection of bacterial cells within bone by 24 h and viable counting of crushed bone blocks was used to determine bacterial survival. Challenge of 72 h biofilms with gentamicin and daptomycin for 24 h demonstrated that only concentrations of 10 times the clinical peak serum target levels (100 mg l-1 gentamicin and 1000 mg l-1 daptomycin) resulted in significant reductions in cell viability compared to controls. Once daily dosing over 7 days resulted in ≥3 log reductions in cell numbers by 48 h. Thereafter no significant reduction was achieved, although emergence of resistance was suppressed. Determination of antibiotic concentration in bone blocks over 7 days indicated that neither agent was able to consistently reach levels in bone of >10% of the original dose. The model was, therefore, able to demonstrate the challenges posed by biofilm growth on and within bone. SIGNIFICANCE AND IMPACT OF THE STUDY: The majority of studies of antibiotic efficacy in the treatment of chronic osteomyelitis are carried out in animals. We developed an in vitro model of Staphylococcus aureus infection of bone to evaluate the ability of antibiotics to eradicate mature biofilms on surfaces analogous to necrotic bone. The results demonstrated the difficulties which occur in osteomyelitis treatment, with only very high concentrations of antibiotic able to penetrate the bone sufficiently to reduce bacterial survival whilst still failing to eradicate biofilms. This model could be of use in initial screening of novel compounds intended for use in the treatment of osteomyelitis.},
}
@article {pmid30770403,
year = {2019},
author = {Liu, YL and He, TT and Liu, LY and Yi, J and Nie, P and Yu, HB and Xie, HX},
title = {The Edwardsiella piscicida Type III Translocon Protein EseC Inhibits Biofilm Formation by Sequestering EseE.},
journal = {Applied and environmental microbiology},
volume = {85},
number = {8},
pages = {},
doi = {10.1128/AEM.02133-18},
pmid = {30770403},
issn = {1098-5336},
abstract = {The type III secretion system (T3SS) is one of the most important virulence factors of the fish pathogen Edwardsiella piscicida It contains three translocon proteins, EseB, EseC, and EseD, required for translocation of effector proteins into host cells. We have previously shown that EseB forms filamentous appendages on the surface of E. piscicida, and these filamentous structures mediate bacterial cell-cell interactions promoting autoaggregation and biofilm formation. In the present study, we show that EseC, but not EseD, inhibits the autoaggregation and biofilm formation of E. piscicida At 18 h postsubculture, a ΔeseC strain developed strong autoaggregation and mature biofilm formation, accompanied by enhanced formation of EseB filamentous appendages. This is in contrast to the weak autoaggregation and immature biofilm formation seen in the E. piscicida wild-type strain. EseE, a protein that directly binds to EseC and also positively regulates the transcription of the escC-eseE operon, was liberated and showed increased levels in the absence of EseC. This led to augmented transcription of the escC-eseE operon, thereby increasing the steady-state protein levels of intracellular EseB, EseD, and EseE, as well as biofilm formation. Notably, the levels of intracellular EseB and EseD produced by the ΔeseE and ΔeseC ΔeseE strains were similar but remarkably lower than those produced by the wild-type strain at 18 h postsubculture. Taken together, we have shown that the translocon protein EseC inhibits biofilm formation through sequestering EseE, a positive regulator of the escC-eseE operon.IMPORTANCEEdwardsiella piscicida, previously known as Edwardsiella tarda, is a Gram-negative intracellular pathogen that mainly infects fish. The type III secretion system (T3SS) plays a pivotal role in its pathogenesis. The T3SS translocon protein EseB is required for the assembly of filamentous appendages on the surface of E. piscicida The interactions between the appendages facilitate autoaggregation and biofilm formation. In this study, we explored the role of the other two translocon proteins, EseC and EseD, in biofilm formation. We have demonstrated that EseC, but not EseD, inhibits the autoaggregation and biofilm formation of E. piscicida, providing new insights into the regulatory mechanism involved in E. piscicida biofilm formation.},
}
@article {pmid30770093,
year = {2019},
author = {Dorji, D and Graham, RM and Singh, AK and Ramsay, JP and Price, P and Lee, S},
title = {Immunogenicity and protective potential of Bordetella pertussis biofilm and its associated antigens in a murine model.},
journal = {Cellular immunology},
volume = {337},
number = {},
pages = {42-47},
doi = {10.1016/j.cellimm.2019.01.006},
pmid = {30770093},
issn = {1090-2163},
abstract = {The resurgence of whooping cough reflects novel genetic variants of Bordetella pertussis and inadequate protection conferred by current acellular vaccines (aP). Biofilm is a source of novel vaccine candidates, including membrane protein assembly factor (BamB) and lipopolysaccharide assembly protein (LptD). Responses of BALB/c mice to candidate vaccines included IFN-γ and IL-17a production by spleen and lymph node cells, and serum IgG1 and IgG2a reactive with whole bacteria or aP. Protection was determined using bacterial cultured from lungs of vaccinated mice challenged with virulent B. pertussis. Mice vaccinated with biofilm produced efficient IFN-γ responses and more IL-17a and IgG2a than mice vaccinated with planktonic cells, aP or adjuvant alone. Vaccination with aP produced abundant IgG1 with little IgG2a. Mice vaccinated with aP plus BamB and LptD retained lower bacterial loads than mice vaccinated with aP alone. Whooping cough vaccines formulated with biofilm antigens, including BamB and LptD, may have clinical value.},
}
@article {pmid30769135,
year = {2019},
author = {Ashton, NN and Allyn, G and Porter, ST and Haussener, TJ and Sebahar, PR and Looper, RE and Williams, DL},
title = {In vitro testing of a first-in-class tri-alkylnorspermidine-biaryl antibiotic in an anti-biofilm silicone coating.},
journal = {Acta biomaterialia},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.actbio.2019.02.010},
pmid = {30769135},
issn = {1878-7568},
support = {I01 RX001198/RX/RRD VA/United States ; },
abstract = {Biofilm-related infection is among the worst complication to prosthetic joint replacement procedures; once established on the implant surface, biofilms show strong recalcitrance to clinical antibiotic therapy, frequently requiring costly revision procedures and prolonged systemic antibiotics for their removal. A well-designed active release coating might assist host immunity in clearing bacterial contaminants within the narrow perioperative window and ultimately prevent microbial colonization of the joint prosthesis. A first-in-class compound (CZ-01127) was tested as the active release agent in a silicone (Si) coating using an in vitro dynamic flow model of surgical site contamination and compared with analogous coatings containing clinical gold-standard antibiotics vancomycin and gentamicin; the CZ-01127 coating outperformed both vancomycin and gentamicin coatings and was the only to decrease the methicillin-resistant Staphylococcus aureus (MRSA) inocula below detectable limits for the first 3 days. The antimicrobial activity of CZ-01127, and for comparison vancomycin and gentamicin, were characterized against both planktonic and biofilm MRSA using the minimum inhibitory concentration (MIC) assay, serial passages, and serial dilution tests against established biofilms grown with a CBR 90 CDC biofilm reactor. Despite a similar MIC (1 µg/ml) and behavior in a 25-day serial passage analysis, CZ-01127 displayed much greater bactericidal activity against established biofilms and was the only to decrease biofilm colony forming units (CFUs) below detectable limits at the highest concentration tested (500 µg/ml). Coating release profiles were characterized using ATR-FTIR and displayed burst release kinetics within the decisive period of the perioperative window suggesting the silicon carrier is broadly useful for screening antibiotic compound for local delivery applications. STATEMENT OF SIGNIFICANCE: With an aging population, an increasing number of people are undergoing total joint replacement procedures in which diseased joint tissues are replaced with permanent metallic implants. Some of these procedures are burdened by costly and debilitating infections. A promising approach to prevent infections is the use of an antimicrobial coating on the surface of the implant which releases antibiotics into the surgical site to prevent infection. In this study, we tested a new antibiotic compound formulated in a silicone coating. Data showed that this compound was more effective at killing pathogenic methicillin resistant Staphylococcus aureus (MRSA) bacteria than two clinical gold-standard antibiotics-vancomycin and gentamicin-and could be a promising agent for antimicrobial coating technologies.},
}
@article {pmid30769118,
year = {2019},
author = {Kovács, ÁT and Dragoš, A},
title = {Evolved Biofilm: Review on the Experimental Evolution Studies of Bacillus subtilis Pellicles.},
journal = {Journal of molecular biology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jmb.2019.02.005},
pmid = {30769118},
issn = {1089-8638},
abstract = {For several decades, laboratory evolution has served as a powerful method to manipulate microorganisms and to explore long-term dynamics in microbial populations. Next to canonical Escherichia coli planktonic cultures, experimental evolution has expanded into alternative cultivation methods and species, opening the doors to new research questions. Bacillus subtilis, the spore-forming and root-colonizing bacterium, can easily develop in the laboratory as a liquid-air interface colonizing pellicle biofilm. Here, we summarize recent findings derived from this tractable experimental model. Clonal pellicle biofilms of B. subtilis can rapidly undergo morphological and genetic diversification creating new ecological interactions, for example, exploitation by biofilm non-producers. Moreover, long-term exposure to such matrix non-producers can modulate cooperation in biofilms, leading to different phenotypic heterogeneity pattern of matrix production with larger subpopulation of &quot;ON&quot; cells. Alternatively, complementary variants of biofilm non-producers, each lacking a distinct matrix component, can engage in a genetic division of labor, resulting in superior biofilm productivity compared to the &quot;generalist&quot; wild type. Nevertheless, inter-genetic cooperation appears to be evanescent and rapidly vanquished by individual biofilm formation strategies altering the amount or the properties of the remaining matrix component. Finally, fast-evolving mobile genetic elements can unpredictably shift intra-species interactions in B. subtilis biofilms. Understanding evolution in clonal biofilm populations will facilitate future studies in complex multispecies biofilms that are more representative of nature.},
}
@article {pmid30768237,
year = {2019},
author = {Kang, M and Kim, S and Kim, H and Song, Y and Jung, D and Kang, S and Seo, JH and Nam, S and Lee, Y},
title = {Calcium-Binding Polymer-Coated Poly(lactide- co-glycolide) Microparticles for Sustained Release of Quorum Sensing Inhibitors to Prevent Biofilm Formation on Hydroxyapatite Surfaces.},
journal = {ACS applied materials &amp; interfaces},
volume = {11},
number = {8},
pages = {7686-7694},
doi = {10.1021/acsami.8b18301},
pmid = {30768237},
issn = {1944-8252},
abstract = {Quorum sensing (QS) inhibitor-based therapy is an attractive strategy to inhibit bacterial biofilm formation without excessive induction of antibiotic resistance. Thus, we designed Ca2+-binding poly(lactide- co-glycolide) (PLGA) microparticles that can maintain a sufficient concentration of QS inhibitors around hydroxyapatite (HA) surfaces in order to prevent biofilm formation on HA-based dental or bone tissues or implants and, therefore, subsequent pathogenesis. Poly(butyl methacrylate- co-methacryloyloxyethyl phosphate) (PBMP) contains both Ca2+-binding phosphomonoester groups and PLGA-interacting butyl groups. The PBMP-coated PLGA (PLGA/PBMP) microparticles exhibited superior adhesion to HA surfaces without altering the sustained release properties of uncoated PLGA microparticles. PLGA/PBMP microparticle-encapsulating furanone C-30, a representative QS inhibitor, effectively inhibited the growth of Streptococcus mutans and its ability to form biofilms on HA surface for prolonged periods of up to 100 h, which was much longer than either furanone C-30 in its free form or when encapsulated in noncoated PLGA microparticles.},
}
@article {pmid30767811,
year = {2019},
author = {Perez, LRR},
title = {Why do susceptible bacteria become resistant to infection control measures? A Pseudomonas biofilm example.},
journal = {Infection control and hospital epidemiology},
volume = {40},
number = {3},
pages = {386-388},
doi = {10.1017/ice.2018.348},
pmid = {30767811},
issn = {1559-6834},
}
@article {pmid30767709,
year = {2019},
author = {Liu, Y and Lin, C and Jia, H and Yong, X and Xie, X and Wu, X and Zhou, J and Wei, P},
title = {Effects of amino-modified biofilm carriers on biogas production in the anaerobic digestion of corn straw.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-11},
doi = {10.1080/09593330.2019.1583290},
pmid = {30767709},
issn = {1479-487X},
abstract = {This paper studied the property of three different biofilm carriers added into the anaerobic digestion systems, a granular activated carbon, a polyacrylonitrile, and a polyacrylonitrile modified with diethylenetriamine (PAN-NH2). The PAN-NH2 system kept the maximum biogas and methane production, which were 42.69% and 37.29% higher than the control system, respectively. The value of pH and chemical oxygen demand, the content of total solid and volatile solid, volatile fatty acids concentration, coenzyme F420 concentration, and microbial community analysis were investigated during the anaerobic digestion process. The PAN-NH2 system had the highest removal efficiency of the pollutants and regulated the pH of the system better than other systems. The result of high-throughput sequencing analysis showed that the addition of biofilm carriers and mediation with amino-groups adjusted system pH and improved biogas and CH4 production by reducing the relative abundance of bacteria in the hydrolysis/acidogenesis stages. Methanosarcina gradually replaced other methanogens during the experimental runs and was the dominant methanogen at the end of the anaerobic digestion process.},
}
@article {pmid30767648,
year = {2019},
author = {Mahmoudi, H and Pourhajibagher, M and Chiniforush, N and Soltanian, AR and Alikhani, MY and Bahador, A},
title = {Biofilm formation and antibiotic resistance in meticillin-resistant and meticillin-sensitive Staphylococcus aureus isolated from burns.},
journal = {Journal of wound care},
volume = {28},
number = {2},
pages = {66-73},
doi = {10.12968/jowc.2019.28.2.66},
pmid = {30767648},
issn = {0969-0700},
abstract = {OBJECTIVE:: To investigate the relationship between biofilm formation and antibiotic resistance patterns in meticillin-resistant and meticillin-sensitive Staphylococcus aureus, isolated from burns.<br><br>METHODS:: In a cross-sectional study, pus/wound swab samples were obtained from burns. Presence of Staphylococcus aureus was confirmed, and biofilm formation-related icaABCDR and eta, etb genes were detected by polymerase chain reaction. Biofilm formation assay was assessed using the microtiter plate method. Antibiotic resistance was performed using the disk diffusion method and minimum inhibitory concentration.<br><br>RESULTS:: A total of 95 patients with burns were recruited. Of the 95 wounds swabbed, Staphylococcus aureus was identified in 50 (62.5%), and 47 (94%) isolates capable of producing biofilm. Biofilm production levels were classed as 'strong' (n=29; 58%), 'moderate' (n=11; 22%), 'weak' (n=7; 14%) and 'non-biofilm forming' (n=3; 6%). There was an almost even split between isolates identified as meticillin-resistant Staphylococcus aureus (MRSA), n=24 (48%), and meticillin-sensitive Staphylococcus aureus (MSSA) n=26 (52%). The prevalence of the icaA, icaB, icaC, icaD and icaR genes among the studied isolates were 96%, 80%, 80%, 96% and 84%, respectively. The prevalence of eta and etb genes in isolates were 84% and 92%, respectively.<br><br>CONCLUSION:: Biofilm producing isolates of Staphylococcus aureus showed greater multidrug resistance than non-biofilm producers. In our study, a high rate of biofilm formation and antimicrobial drug resistance was seen. Our results highlight the alarming levels of antimicrobial resistance among MRSA strains and important data about the prevalence of eta and etb genes in Staphylococcus aureus strains isolated from burn patients in this study.},
}
@article {pmid30767627,
year = {2019},
author = {Gupta, A and Cheepurupalli, L and Vigneswaran, S and Singh Rathore, S and Suma Mohan, S and Ramakrishnan, J},
title = {In vitro and in silico investigation of caprylic acid effect on multi drug resistant (MDR) Klebsiella pneumoniae biofilm.},
journal = {Journal of biomolecular structure &amp; dynamics},
volume = {},
number = {},
pages = {1-9},
doi = {10.1080/07391102.2019.1581087},
pmid = {30767627},
issn = {1538-0254},
}
@article {pmid30766602,
year = {2019},
author = {Galdiero, E and Siciliano, A and Gesuele, R and Di Onofrio, V and Falanga, A and Maione, A and Liguori, R and Libralato, G and Guida, M},
title = {Melittin Inhibition and Eradication Activity for Resistant Polymicrobial Biofilm Isolated from a Dairy Industry after Disinfection.},
journal = {International journal of microbiology},
volume = {2019},
number = {},
pages = {4012394},
doi = {10.1155/2019/4012394},
pmid = {30766602},
issn = {1687-918X},
abstract = {The emerging concern about the increase of antibiotic resistance and associated biofilm has encouraged scientists to look for alternative antibiotics such as antimicrobial peptides (AMPs). This study evaluated the ability of melittin to act as an antibacterial biofilm inhibitor and biofilm remover considering isolates from dairy industry. Minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), minimum biofilm inhibitory concentrations (MBICs), and biofilm removal activities were studied in polymicrobial biofilms produced from isolates. MIC and MBC were set at 1-3 µg/mL and 25-50 µg/mL for Gram-positive and Gram-negative bacteria, respectively. Results demonstrated a good MBIC reaching 85% inhibition ability and a good activity and better penetration in deeper layers against the mixed preformed biofilm, thereby increasing its activity against all isolates also at the lowest tested concentrations. Melittin showed interesting characteristics suggesting its potential to act as an antimicrobial agent for polymicrobial biofilm from dairy industry even in environmental isolates.},
}
@article {pmid30766582,
year = {2018},
author = {Kadry, AA and El-Ganiny, AM and El-Baz, AM},
title = {Relationship between Sap prevalence and biofilm formation among resistant clinical isolates of Candida albicans.},
journal = {African health sciences},
volume = {18},
number = {4},
pages = {1166-1174},
doi = {10.4314/ahs.v18i4.37},
pmid = {30766582},
issn = {1729-0503},
abstract = {Background: Fungal infections represent a serious health problem especially in immunocompromised individuals. Candida albicans is the most common fungi that cause superficial and systemic infections with high mortality rates. Anti-fungal resistance of C. albicans may be attributed to its virulence. Biofilm formation and proteolytic activity are major virulence determents that may influence both pathogenicity and anti-fungal resistance of Candida albicans.<br><br>Objective: This work studied the relation between biofilm formation, proteolytic activity and prevalence of some Sap genes with reduced susceptibility of C. albicans to different anti-fungal agents.<br><br>Methods: Fifty three C. albicans strains isolated from patients with systemic infections, identified by germ tube, chromogenic agar and confirmed by PCR, were subjected to evaluate their proteolytic activity, the degree of biofilm production and the prevalence of Sap9 and Sap10 genes. The susceptibility of the isolates was determined by disk diffusion method against five antifungal drugs.<br><br>Results and conclusion: Four of the C. albicans isolates were resistant to 3 anti-fungal drugs, strong biofilm producer, have proteolytic activity and contain either Sap9 or Sap10 or both. Conclusively, although anti-fungal resistance among the isolates was rare, a relation between the anti-fungal resistance and some major virulence factors was evidently proved in this study.},
}
@article {pmid30763694,
year = {2019},
author = {Doğan, Ş and Gökalsın, B and Şenkardeş, İ and Doğan, A and Sesal, NC},
title = {Anti-quorum sensing and anti-biofilm activities of Hypericum perforatum extracts against Pseudomonas aeruginosa.},
journal = {Journal of ethnopharmacology},
volume = {235},
number = {},
pages = {293-300},
doi = {10.1016/j.jep.2019.02.020},
pmid = {30763694},
issn = {1872-7573},
abstract = {Hypericum perforatum L. (Hypericaceae) has been used as a traditional therapeutic for skin wounds, burns, cuts and stomach ailments including stomach ache, ulcers for a long time in many societies. Although many studies about its antibacterial properties can be found, there is a lack of studies about its quorum sensing inhibition properties, which effects bacterial vulnerability directly, on Pseudomonas aeruginosa.<br><br>AIM OF THE STUDY: Evaluation of anti-quorum sensing (anti-QS) and anti-biofilm activity of ethanol, methanol, acetone and ultra-sonicated extracts of Hypericum perforatum L. (HP) which is a well-known wound healer, against P. aeruginosa.<br><br>MATERIALS AND METHODS: Aerial parts of HP were extracted with ethanol, methanol and acetone. In addition, separate extractions with ultrasonication were carried out with same solvents. Anti-QS activity tests with different doses of HP extracts were performed by employing biomonitor strains, of which the promoter of QS regulating and green fluorescent protein (GFP) genes were fusioned. For anti-biofilm activity, HP extracts were applied to wild type PAO1 strains and biofilm inhibition was quantified via crystal violet staining method.<br><br>RESULTS: HP's ethanol, methanol and acetone extracts (250 µg/ml doses) inhibited LasIR signalling pathway up to 65.43%, 59.60%, 55.95% and same solvent extracts obtained with ultrasonication inhibited 71.33%, 64.47%, 57.35% respectively. Moreover, inhibition rates of RhlIR pathway were 28.80%, 50.83%, 45.84% for ethanol, methanol, acetone extracts (250 µg/ml doses) and 51.43%, 57.41%, 50.02% for ultrasonication extracts (250 µg/ml doses), compared to untreated controls. In the experiments, ethanol, methanol, acetone and ultra-sonicated extracts of HP did not inhibit biofilm formation.<br><br>CONCLUSIONS: This study shows that HP plant is capable for blocking of las and rhl QS systems of P. aeruginosa. However, it was observed that ethanol, methanol and acetone extract of the plant samples did not show anti-biofilm activity against P. aeruginosa. This led us to thinking that biofilm formation was caused via another pathway such as IQS or PQS. Further studies with isolated active compounds of HP might give a better understanding of the effects on biofilm formation of P. aeruginosa.},
}
@article {pmid30763382,
year = {2019},
author = {Cooke, AC and Nello, AV and Ernst, RK and Schertzer, JW},
title = {Analysis of Pseudomonas aeruginosa biofilm membrane vesicles supports multiple mechanisms of biogenesis.},
journal = {PloS one},
volume = {14},
number = {2},
pages = {e0212275},
doi = {10.1371/journal.pone.0212275},
pmid = {30763382},
issn = {1932-6203},
abstract = {Outer Membrane Vesicles (OMVs) are ubiquitous in bacterial environments and enable interactions within and between species. OMVs are observed in lab-grown and environmental biofilms, but our understanding of their function comes primarily from planktonic studies. Planktonic OMVs assist in toxin delivery, cell-cell communication, horizontal gene transfer, small RNA trafficking, and immune system evasion. Previous studies reported differences in size and proteomic cargo between planktonic and agar plate biofilm OMVs, suggesting possible differences in function between OMV types. In Pseudomonas aeruginosa interstitial biofilms, extracellular vesicles were reported to arise through cell lysis, in contrast to planktonic OMV biogenesis that involves the Pseudomonas Quinolone Signal (PQS) without appreciable autolysis. Differences in biogenesis mechanism could provide a rationale for observed differences in OMV characteristics between systems. Using nanoparticle tracking, we found that P. aeruginosa PAO1 planktonic and biofilm OMVs had similar characteristics. However, P. aeruginosa PA14 OMVs were smaller, with planktonic OMVs also being smaller than their biofilm counterparts. Large differences in Staphylococcus killing ability were measured between OMVs from different strains, and a smaller within-strain difference was recorded between PA14 planktonic and biofilm OMVs. Across all conditions, the predatory ability of OMVs negatively correlated with their size. To address biogenesis mechanism, we analyzed vesicles from wild type and pqsA mutant biofilms. This showed that PQS is required for physiological-scale production of biofilm OMVs, and time-course analysis confirmed that PQS production precedes OMV production as it does in planktonic cultures. However, a small sub-population of vesicles was detected in pqsA mutant biofilms whose size distribution more resembled sonicated cell debris than wild type OMVs. These results support the idea that, while a small and unique population of vesicles in P. aeruginosa biofilms may result from cell lysis, the PQS-induced mechanism is required to generate the majority of OMVs produced by wild type communities.},
}
@article {pmid30763337,
year = {2019},
author = {Jijón-Moreno, S and Baca, BE and Castro-Fernández, DC and Ramírez-Mata, A},
title = {TyrR is involved in the transcriptional regulation of biofilm formation and D-alanine catabolism in Azospirillum brasilense Sp7.},
journal = {PloS one},
volume = {14},
number = {2},
pages = {e0211904},
doi = {10.1371/journal.pone.0211904},
pmid = {30763337},
issn = {1932-6203},
abstract = {Azospirillum brasilense is one of the most studied species of diverse agronomic plants worldwide. The benefits conferred to plants inoculated with Azospirillum have been primarily attributed to its capacity to fix atmospheric nitrogen and synthesize phytohormones, especially indole-3-acetic acid (IAA). The principal pathway for IAA synthesis involves the intermediate metabolite indole pyruvic acid. Successful colonization of plants by Azospirillum species is fundamental to the ability of these bacteria to promote the beneficial effects observed in plants. Biofilm formation is an essential step in this process and involves interactions with the host plant. In this study, the tyrR gene was cloned, and the translated product was observed to exhibit homology to TyrR protein, a NtrC/NifA-type activator. Structural studies of TyrR identified three putative domains, including a domain containing binding sites for aromatic amino acids in the N-terminus, a central AAA+ ATPase domain, and a helix-turn-helix DNA binding motif domain in the C-terminus, which binds DNA sequences in promoter-operator regions. In addition, a bioinformatic analysis of promoter sequences in A. brasilense Sp7 genome revealed that putative promoters encompass one to three TyrR boxes in genes predicted to be regulated by TyrR. To gain insight into the phenotypes regulated by TyrR, a tyrR-deficient strain derived from A. brasilense Sp7, named A. brasilense 2116 and a complemented 2116 strain harboring a plasmid carrying the tyrR gene were constructed. The observed phenotypes indicated that the putative transcriptional regulator TyrR is involved in biofilm production and is responsible for regulating the utilization of D-alanine as carbon source. In addition, TyrR was observed to be absolutely required for transcriptional regulation of the gene dadA encoding a D-amino acid dehydrogenase. The data suggested that TyrR may play a major role in the regulation of genes encoding a glucosyl transferase, essential signaling proteins, and amino acids transporters.},
}
@article {pmid30762887,
year = {2019},
author = {Vipin, C and Mujeeburahiman, M and Ashwini, P and Arun, AB and Rekha, PD},
title = {Anti-biofilm and cytoprotective activities of quercetin against Pseudomonas aeruginosa isolates.},
journal = {Letters in applied microbiology},
volume = {68},
number = {5},
pages = {464-471},
doi = {10.1111/lam.13129},
pmid = {30762887},
issn = {1472-765X},
abstract = {Increase in infection with multidrug resistant Pseudomonas aeruginosa is a serious global challenge in healthcare. Pseudomonas aeruginosa is capable of causing human infection in various sites and complicates the infection due to its virulence factors. This study was aimed to investigate the effect of quercetin, a dietary flavonoid against the virulence factors of P. aeruginosa and its cell protective effects on epithelial cells. Bactericidal activity, anti-biofilm activity and effect on different virulence factors were carried out using standard methods by using five P. aeruginosa isolates. Cytotoxicity and cell protective effect of quercetin was evaluated by trypan blue dye exclusion assay. All the tested isolates were completely inhibited (100%) by quercetin at a concentration of 500 μg ml-1 . It showed significant (P < 0·05) inhibitory effect on virulence factors including biofilm formation and showed significant protective effect on HEK 293T cells infected with P. aeruginosa strains. This study supports the role of quercetin against P. aeruginosa, by inhibiting virulence factors as well as its cytoprotective activity during bacterial infection either by attenuating the virulence or providing direct protective effect to the host cells. SIGNIFICANCE AND IMPACT OF THE STUDY: The increase in infections caused by opportunistic pathogen Pseudomonas aeruginosa is a serious concern in the health care system. This study describes the beneficial effects of a dietary flavonoid, quercetin against pathogenic P. aeruginosa strains and its protective effect against the P. aeruginosa infection in HEK 293T cells in vitro.},
}
@article {pmid30760047,
year = {2019},
author = {Dodou, HV and Batista, AHM and Medeiros, SC and Sales, GWP and Rodrigues, ML and Pereira, PIO and Nogueira, PCN and Silveira, ER and Grangeiro, TB and Nogueira, NAP},
title = {Violacein antimicrobial activity on Staphylococcus epidermidis biofilm.},
journal = {Natural product research},
volume = {},
number = {},
pages = {1-4},
doi = {10.1080/14786419.2019.1569654},
pmid = {30760047},
issn = {1478-6427},
abstract = {The aim of this study was to evaluate the antimicrobial potential of violacein (VIO) on Staphylococcus epidermidis biofilm. The minimum biofilm inhibition concentration (MBIC) and minimum biofilm eradication concentration (MBEC) were determined, as well as the effect of VIO exposure time on microbial viability in mature biofilm. Violacein showed good antibiofilm action, inhibiting biofilm formation and eradicating mature biofilm of S. epidermidis at concentrations of 20 μg.mL-1 and 160 μg.mL-1, respectively. At concentrations equal to MBEC and 2x MBEC, the biofilm was eradicated in 3 h and 2h30min of incubation, respectively.When evaluating VIO modulating effect on the action of clinically-used drugs (vancomycin, cefepime, ciprofloxacin and meropenem), especial synergism was observed in the violacein-ciprofloxacin association, it can completely erradicated the mature biofilm at the concentration of 1/2xMBEC and 1/4xMBEC, respectively. VIO shows good antimicrobial action on S. epidermidis biofilm and has the potential to synergistically modulate the activity of clinically-used antimicrobials.},
}
@article {pmid30758060,
year = {2019},
author = {Costa, DM and Johani, K and Melo, DS and Lopes, LKO and Lopes Lima, LKO and Tipple, AFV and Hu, H and Vickery, K},
title = {Biofilm contamination of high-touched surfaces in intensive care units: epidemiology and potential impacts.},
journal = {Letters in applied microbiology},
volume = {68},
number = {4},
pages = {269-276},
doi = {10.1111/lam.13127},
pmid = {30758060},
issn = {1472-765X},
support = {2015142//Macquarie University/ ; 8210300211//Australian Research Council/ ; 99999.006361/2014-05//Coordination for the Improvement of Higher Education Personnel (CAPES) Scholarship/ ; 99999.006360/2014-09//Coordination for the Improvement of Higher Education Personnel (CAPES) Scholarship/ ; //Medical Services Department (MSD) of the Ministry of Defense and Aviation, Saudi Arabia/ ; },
abstract = {The aim of this study was to determine the epidemiology (location, microbial load, microbiome, presence/absence of biofilm and pathogens, including ESKAPE-Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species, and antimicrobial susceptibility profiles) of the bacterial contamination on intensive care units (ICUs) surfaces. Fifty-seven high-touched surfaces were collected from adult, paediatric and neonatal ICUs from two large public Brazilian hospitals from central and north regions. Samples (c. 4 cm2) were subjected to culture (qualitative), qPCR targeting 16s rRNA gene (microbial load-bacteria per cm2), 16s rRNA amplicon sequencing (microbiome analysis) and scanning electron (SEM) or confocal laser scanning microscopy (CLSM) (biofilm presence). Multidrug resistant organisms (MROs) were detected using specific chromogenic agar. The average bacterial load was 1·32 × 104 bacteria per cm2 , container for newborn feeding bottles, stretcher mattress, humidicrib mattress filling and computer keyboards presented the higher bioburden. However, only 45·6% (26/57) were culture-positive, including 4/26 with MROs. ESKAPE organisms were detected in 51·8% of the samples subjected to next-generation sequencing. Viability staining and CLSM demonstrated live bacteria on 76·7% of culture-negative samples. Biofilm was present on all surfaces subjected to microscopy (n = 56), demonstrating that current cleaning practices are suboptimal and reinforcing that MROs are incorporated into hospital surfaces biofilm. SIGNIFICANCE AND IMPACT OF THE STUDY: Contamination of healthcare facilities surfaces has been shown to play a major role in transmission of pathogens. The findings of this study show that dry surface biofilms are widespread and can incorporate pathogens and multidrug-resistant organisms (MROs). Biofilms on highly touched surfaces pose a risk to patients, as dry surface biofilms persist for long period and micro-organisms within biofilm have been shown to be transmitted. This study also provides a better understanding of microbial populations in hospital environments, reinforcing that pathogens and MROs are found incorporated into biofilm, which impacts the difficulty in cleaning/disinfection.},
}
@article {pmid30747987,
year = {2018},
author = {Holý, O and Matoušková, I and Zatloukalová, S and Dvořáčková, M and Petrželová, J and Raida, L and Růžička, F},
title = {[Prevalence of strains of Staphylococcus epidermidis and other coagulase-negative staphylococci with biofilm-forming ability at a department of hemato-oncology].},
journal = {Klinicka mikrobiologie a infekcni lekarstvi},
volume = {24},
number = {3},
pages = {68-72},
pmid = {30747987},
issn = {1211-264X},
mesh = {*Biofilms ; Coagulase/metabolism ; Humans ; Prevalence ; *Staphylococcal Infections/epidemiology/microbiology ; *Staphylococcus epidermidis/physiology ; },
abstract = {OBJECTIVES: Staphylococcus epidermidis and coagulase-negative staphylococci generally are important causative agents of hospital-acquired infections. A significant role in this process is played by their common ability to form biofilm, a highly organized community of microorganisms adhering to inert surfaces. The study aimed to determine the prevalence of these bacterial strains and their ability to form biofilm at the Department of Hemato-Oncology, University Hospital Olomouc.<br><br>MATERIAL AND METHODS: Over a period of 12 months, samples of air and swabs from surfaces and staff members were collected. The samples were subjected to standard microbiology tests; coagulase-negative staphylococci were identified. Staphylococcus epidermidis strains were confirmed by polymerase chain reaction and subsequently tested for biofilm formation.<br><br>RESULTS AND CONCLUSIONS: Coagulase-negative staphylococci were found in 81 samples, most commonly swabs from staff members. S. epidermidis accounted for 60 % of all positive results; it was most frequently isolated from surface swabs. Almost half of S. epidermidis strains were able to form biofilm. These strains were found in the environment characterized by cleanliness classes FED-STD-209E (USA) - 10 000 and FED-STD-209E (USA) - 100 000. Thus, they pose a risk for immunocompromised patients staying there. Since coagulase-negative staphylococci were also found in healthcare staff of the department, the staff members may play a key role in the transmission of these microorganisms to patients.},
}
@article {pmid30745897,
year = {2019},
author = {Martins, KB and Ferreira, AM and Pereira, VC and Pinheiro, L and de Oliveira, A and da Cunha, MLRS},
title = {In vitro Effects of Antimicrobial Agents on Planktonic and Biofilm Forms of Staphylococcus saprophyticus Isolated From Patients With Urinary Tract Infections.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {40},
doi = {10.3389/fmicb.2019.00040},
pmid = {30745897},
issn = {1664-302X},
abstract = {Bacterial biofilms play an important role in urinary tract infections (UTIs), being responsible for persistent infections that lead to recurrences and relapses. Staphylococcus saprophyticus is one of the main etiological agents of UTIs, however, little is known about biofilm production in this species and especially about its response to the antimicrobial agents used to treat UTIs when a biofilm is present. For this reason, the aim of this work was to evaluate the response of S. saprophyticus biofilms to five antimicrobial agents. Staphylococcus saprophyticus was evaluated for antimicrobial susceptibility in its planktonic form by means of minimum inhibitory concentration (MIC) and in biofilms by means of minimum inhibitory concentration in biofilm (MICB) against the following antimicrobial agents by the microdilution technique: vancomycin, oxacillin, trimethoprim/sulfamethoxazole, ciprofloxacin, and norfloxacin. Of the 169 S. saprophyticus studied, 119 produced a biofilm as demonstrated by the polystyrene plate adherence method. Biofilm cells of S. saprophyticus exhibited a considerable increase in MICB when compared to the planktonic forms, with an increase of more than 32 times in the MICB of some drugs. Some isolates switched from the category of susceptible in the planktonic condition to resistant in the biofilm state. Statistical analysis of the results showed a significant increase in MICB (p < 0.0001) for all five drugs tested in the biofilm state compared to the planktonic form. Regarding determination of the minimum bactericidal concentration in biofilm (MBCB), there were isolates for which the minimum bactericidal concentration of all drugs was equal to or higher than the highest concentration tested.},
}
@article {pmid30744421,
year = {2018},
author = {Souza, JGS and Lima, CV and Costa Oliveira, BE and Ricomini-Filho, AP and Faveri, M and Sukotjo, C and Feres, M and Del Bel Cury, AA and Barão, VAR},
title = {Dose-response effect of chlorhexidine on a multispecies oral biofilm formed on pure titanium and on a titanium-zirconium alloy.},
journal = {Biofouling},
volume = {34},
number = {10},
pages = {1175-1184},
doi = {10.1080/08927014.2018.1557151},
pmid = {30744421},
issn = {1029-2454},
abstract = {This study aimed to test the dose-response effect of chlorhexidine on multispecies biofilms formed on commercially pure titanium (cpTi) and titanium-zirconium (TiZr) alloy. Biofilms were formed on cpTi and TiZr discs and treated two times per day with five different chlorhexidine concentrations (0.12, 0.20, 0.50, 1, 2%). The biofilms were collected for microbiological, biochemical and microscopic analyses. The significance of differences among groups was evaluated by linear regression, ANOVA, Bonferroni and Tukey tests. The mean number of colony-forming units decreased as the chlorhexidine concentration increased for both cpTi and TiZr (p < 0.05). The maximum effect was observed with the 0.5% concentration. Confocal microscopy images suggested an increase in the number of dead bacterial cells with increased chlorhexidine concentration. The biofilm pH increased after chlorhexidine exposure (p < 0.05). Chlorhexidine showed an antimicrobial dose-response effect in controlling biofilm on cpTi and TiZr. 0.5% chlorhexidine can be used to achieve the maximum antimicrobial effect on both materials.},
}
@article {pmid30744166,
year = {2019},
author = {Kang, Y and Li, L and Li, S and Zhou, X and Xia, K and Liu, C and Qu, Q},
title = {Temporary Inhibition of the Corrosion of AZ31B Magnesium Alloy by Formation of Bacillus subtilis Biofilm in Artificial Seawater.},
journal = {Materials (Basel, Switzerland)},
volume = {12},
number = {3},
pages = {},
doi = {10.3390/ma12030523},
pmid = {30744166},
issn = {1996-1944},
support = {51661033, 51361028, 51161025, and 31660538.//National Natural Science Foundation of China/ ; },
abstract = {It is well known that microorganisms tend to form biofilms on metal surfaces to accelerate/decelerate corrosion and affect their service life. Bacillus subtilis was used to produce a dense biofilm on an AZ31B magnesium alloy surface. Corrosion behavior of the alloy with the B. subtilis biofilm was evaluated in artificial seawater. The results revealed that the biofilm hampered extracellular electron transfer significantly, which resulted in a decrease of icorr and increase of Rt clearly compared to the control group. Moreover, an ennoblement of Ecorr was detected under the condition of B. subtilis biofilm covering. Significant reduction of the corrosion was observed by using the cyclic polarization method. All of these prove that the existence of the B. subtilis biofilm effectively enhances the anti-corrosion performance of the AZ31B magnesium alloy. This result may enhance the usage of bio-interfaces for temporary corrosion control. In addition, a possible corrosion inhibition mechanism of B. subtilis on AZ31B magnesium alloy was proposed.},
}
@article {pmid30743828,
year = {2018},
author = {Lai, CY and Dong, QY and Zhao, HP},
title = {Oxygen exposure deprives antimonate-reducing capability of a methane fed biofilm.},
journal = {The Science of the total environment},
volume = {644},
number = {},
pages = {1152-1159},
doi = {10.1016/j.scitotenv.2018.07.047},
pmid = {30743828},
issn = {1879-1026},
mesh = {Antimony/*metabolism ; Biofilms ; Bioreactors/*microbiology ; Methane/*metabolism ; Oxygen/metabolism ; Waste Disposal, Fluid/methods ; },
abstract = {This work is aiming at achieving antimonate (Sb(V)) bio-reduction in a methane (CH4) based membrane biofilm reactor (MBfR), and elucidating the effect of oxygen (O2) on the performance of the biofilm. Scanning electron microscope (SEM), energy dispersive X-ray (EDS) and X-ray photoelectron spectroscopy (XPS) confirm Sb2O3 precipitates were the main product formed from Sb(V) reduction in the CH4-fed biofilm. Illumina sequencing shows Thermomonas may be responsible for Sb(V) reduction. Moreover, we found 8 mg/L of O2 in the influent irreversibly inhibited Sb(V) reduction. Metagenomic prediction by Reconstruction of Unobserved State (PICRUSt) shows that the biofilm lacked efficient defense system to the oxidative stress, leading to the great suppress of key biological metabolisms such as TCA cycle, glycolysis and DNA replication, as well as potential Sb(V) reductases, by O2. However, methanotrophs Methylomonas and Methylosinus were enriched in the biofilm with O2 intrusion, in accordance with the enhanced abundance of genes encoding aerobic CH4 oxidation. These insights evoke the theoretical guidance of microbial remediation using CH4 as the electron donor towards Sb(V) contamination, and will give us a strong reference with regard to wastewater disposal.},
}
@article {pmid30743237,
year = {2019},
author = {Chen, X and Xiong, X and Jiang, X and Shi, H and Wu, C},
title = {Sinking of floating plastic debris caused by biofilm development in a freshwater lake.},
journal = {Chemosphere},
volume = {222},
number = {},
pages = {856-864},
doi = {10.1016/j.chemosphere.2019.02.015},
pmid = {30743237},
issn = {1879-1298},
mesh = {Biofilms/*growth &amp; development ; *Environmental Monitoring ; Environmental Pollution/analysis ; Lakes/*microbiology ; Plastics/*analysis ; Polypropylenes ; *Seasons ; Waste Products/analysis ; },
abstract = {Plastic pollution has been increasingly reported in both marine environment and inland waters, but their fate is not well understood. Several studies have showed that the surface of plastic debris can be colonized by microbes, leading to the sinking of floating plastic debris in marine environment. In this work, development of biofilm on polypropylene sheet (squares with a side length of 5 and 10 mm) and their buoyancy changes were studied in a freshwater lake in four seasons. Results showed that biofilm development have different growth rate and distinct algae composition in different seasons, which are mainly related to the difference in temperature, nutrient levels, and suspend solids in lake water. Biofilm development was much quicker on small plastics in all seasons. At the end of the experiment, all plastics lost buoyancy in summer while only a small portion lost buoyance in other seasons. Sinking of the floating plastics can be attributed to the development of biofilm and the trapped minerals. Our results demonstrated that biofilm development can cause the sinking of floating plastics in fresh lakes but the time required to lose buoyance can differ seasonally. Floating plastics will remain in water for a longer time in cold season but sink in a short time in warm season. Future research is required to determine the influence of plastic types and shapes, and quantitative relation between environmental variables and the sinking behavior of the fouled plastics should be established for a better prediction of their fate in the freshwater environment.},
}
@article {pmid30743061,
year = {2019},
author = {Zhang, R and Neu, TR and Blanchard, V and Vera, M and Sand, W},
title = {Biofilm dynamics and EPS production of a thermoacidophilic bioleaching archaeon.},
journal = {New biotechnology},
volume = {51},
number = {},
pages = {21-30},
doi = {10.1016/j.nbt.2019.02.002},
pmid = {30743061},
issn = {1876-4347},
abstract = {Bioleaching of metal sulfides represents an interfacial process where biofilm formation is important in the initial steps of this process. In technical applications of bioleaching, such as reactor leaching in the temperature range of 50 up to 90 °C and also in (self-heating) heaps, thermophilic archaea play an important role and often are the leaching organisms of choice. Nevertheless, to date there is little information available on the interactions between thermoacidophilic archaea and their natural mineral substrates such as pyrite. Especially for extracellular polymeric substances (EPS) of archaea and their biofilms in bioleaching environments information is rather limited. The present work focused on investigations of biofilm dynamics and EPS production of the thermoacidophilic archaeon Acidianus sp. DSM 29099 under bioleaching conditions. The results show that biofilms are dispersed non-homogeneously on pyrite. Large parts of the pyrite surfaces remain free of cells. Cell detachment from pyrite results in microbial &quot;footprints&quot; which, based on lectin binding assays, consist of mannose, glucose and fucose containing compounds. A monolayer biofilm develops on pyrite after 2-4 days of incubation. In addition, the pyrite surface is covered with a layer of organic compounds. EPS analysis indicates the presence of proteins, polysaccharides and uronic acids, the composition of which varies according to substrate and lifestyle (i.e. planktonic, biofilm cells). This report provides insight into EPS and biofilm characteristics of thermophilic archaea and improves understanding of the mineral-microbial-biofilm interfacial interactions in extreme environments. Moreover, the results on interaction dynamics of archaeal microbial consortia will facilitate the understanding of thermophilic bioleaching.},
}
@article {pmid30742947,
year = {2019},
author = {Tozar, T and Nastasa, V and Stoicu, A and Chifiriuc, MC and Popa, M and Kamerzan, C and Pascu, ML},
title = {In vitro antimicrobial efficacy of laser exposed chlorpromazine against Gram-positive bacteria in planktonic and biofilm growth state.},
journal = {Microbial pathogenesis},
volume = {129},
number = {},
pages = {250-256},
doi = {10.1016/j.micpath.2019.02.012},
pmid = {30742947},
issn = {1096-1208},
abstract = {Aqueous chlorpromazine solutions exposed to 266 nm generated as fourth harmonic of Nd:YAG pulsed laser along time intervals from 1 min to 240 min were investigated for their antimicrobial activity against planktonic and adherent Gram-positive bacterial strains. Qualitative and quantitative assays based on microbiological methods and flow cytometry assays were performed to establish the minimum inhibitory and minimum biofilm eradication concentrations and to reveal some of the possible mechanisms of antimicrobial activity. Optimal irradiation conditions and combinations of photoproducts for achieving the best antimicrobial and antibiofilm effects are suggested. It was confirmed that chlorpromazine solutions irradiated for 15 min and 30 min have the best antimicrobial and antibiofilm activity against Staphylococcus aureus ATCC 6538, methicillin susceptible Staphylococcus aureus, methicillin resistant Staphylococcus aureus, Enterococcus faecium 17-VAR, Enterococcus faecalis 2921, and Bacillus subtilis 6633. Flow cytometry revealed that two of the possible mechanisms of the antimicrobial activity of irradiated chlorpromazine are the inhibition of efflux pumps activity and induction of cellular membrane lesions.},
}
@article {pmid30742347,
year = {2019},
author = {Chen, S and Chen, Y and Pei, H and Hou, Q},
title = {Biofilm development dynamics and pollutant removal performance of ceramsite made from drinking-water treatment sludge.},
journal = {Water environment research : a research publication of the Water Environment Federation},
volume = {},
number = {},
pages = {},
doi = {10.1002/wer.1089},
pmid = {30742347},
issn = {1061-4303},
support = {51322811//National Science Fund for Excellent Young Scholars/ ; NCET-12-0341//University of the Ministry of Education of China/ ; ZR2016EEB26//Foundation for Outstanding Young Scientists in Shandong Province/ ; 51378300//Natural Science Foundation of China/ ; },
abstract = {Alum-sludge ceramsite and denitrifying bacteria (XP-1, XP-2, CL-1, CL-3) were used as substrate and constructed biofilm for enhancing the removal of pollutants from wastewater. The results showed that, due to the large specific surface area, the maximum growth rate was 0.49 mg/(g·day) on the sludge ceramsite, and the mass of biofilm attached onto sludge ceramsite was 5.98 times higher than that when using commercial ceramsite as substrate. Better removal performance could be achieved with the combination of sludge ceramsite and bacteria, viz. 98.6%, 91.0%, and 85.8% reduction in total phosphorus (TP), total nitrogen (TN), and chemical oxygen demand (COD), respectively. Pseudo-first-order kinetics, pseudo-second-order kinetics, Monod kinetics, and multiple Monod kinetics combined with continuous-flow-stirred tank reactor (CFSTR) behavior were used to investigate the dynamics of the pollutant removal processes. The decrease in band brightness for bacteria attached onto sludge ceramsite was 11.5%, while it was more than 35.7% on commercial ceramsite during wastewater treatment according to results from denaturing gradient gel electrophoresis (DGGE). Sludge ceramsite played an important role in maintaining quantities and activities of denitrifying bacteria, and application of sludge ceramsite substrate and denitrifying bacteria was a reliable method to enhance the removals of phosphorus, nitrogen, and COD from domestic wastewater. PRACTITIONER POINTS: Alum-sludge ceramsite was a good substrate for phosphorus adsorption and denitrifying bacterial growth. There was 5.98 times more biofilm on sludge ceramsite than on commercial ceramsite The biofilm of denitrifying bacteria on sludge ceramsite was more stable. High removals of TP (98.6%), TN (90.1%) and COD (85.81%) were achieved.},
}
@article {pmid30741656,
year = {2019},
author = {Bayrak, O and Basmaci, I and Zer, Y and Kirkgoz Karabulut, E and Sen, H and Erturhan, S and Seckiner, I},
title = {Colonizations on biofilm layers of D-J catheters under sterile urine conditions.},
journal = {Archivos espanoles de urologia},
volume = {72},
number = {1},
pages = {75-79},
pmid = {30741656},
issn = {0004-0614},
abstract = {OBJECTIVE: To evaluate colonizations onbiofilm layers of Double J (D-J) catheters implanted forkidney stones or ureteral stones under sterile conditions.<br><br>METHODS: D-J catheters implanted between January2012 and February 2014 and removed in 0-90 days,were examined in microbiology laboratory prospectively.Fifty two patients divided into three groups regardingthe duration of the D-J catheters as; 0-30 days, 31-60days, 61-90 days. The colonization (≥1.000 colony)was reported after biofilm layer on D-J catheter was holdin culture media. The upper, middle and lower parts ofthe catheters were analyzed seperately.<br><br>RESULTS: Thirty five patients had symptomatic urinarytract infection or positive urine culture after implantationwere excluded from the study. Colonization on biofilm layer was detected in 11 patients (21.15%) [Coagulase-negative staphylococci (CNS): 3, Escherichia coli (E. coli): 3, Candida species (Candida spp.): 3, Klebsiella species (Klebsiella spp.): 2]. The rates of colonization according to the duration of the catheterization were; 12.5% in 0-30 days, 18.51% in 30-60 days, 29.4% in 60-90 days (Group 1 vs 2; .696 , group 1 vs group 3; .356 , group 2 vs group 3; .401). The rates of colonization according to the location of the catheter were; 100% in upper and lower parts, 54.4% in middle part (Group 1 vs 2; .011, group 1 vs group 3; , group 2 vs group 3; .011).<br><br>CONCLUSIONS: Colonization on catheters is possibleeven in the sterile urinary conditions according to thepresent findings. The risk of colonization increases 1.5times in 30-60 days and 2.5 times in 60-90 days comparedto the first 30 days. Besides the risk of colonizationincreases about 2 times in the convoluted edges ofthe catheter compared with the middle part. Thus, D-Jcatheter should be removed as soon as possible and therisk of colonization should be minimalized.},
}
@article {pmid30741530,
year = {2019},
author = {Diaz Perez, A and Kougl, K and Vasicek, TW and Liyanage, R and Lay, J and Stenken, JA},
title = {Microdialysis Sampling of Quorum Sensing Homoserine Lactones during Biofilm Formation.},
journal = {Analytical chemistry},
volume = {91},
number = {6},
pages = {3964-3970},
doi = {10.1021/acs.analchem.8b05168},
pmid = {30741530},
issn = {1520-6882},
abstract = {Bacteria communicate chemically through a system called quorum sensing. In this work, microdialysis sampling procedures were optimized to collect quorum sensing molecules produced during in situ biofilm formation directly on the polymeric semipermeable membrane of the microdialysis probe. V. harveyi, a Gram-negative bacterium, was used as the model organism and releases variable chain length acylhomoserine lactones (AHLs) and acyl-oxohomoserine lactones (AOHLs) as signaling molecules during quorum sensing. Eliciting biofilm formation required coating fetal bovine serum onto the poly(ether sulfone) microdialysis membrane. Dialysates were collected in different experiments either during or after biofilm formation directly on a microdialysis probe. Continuous sampling of C4-AHL, C6-AHL, C8-AHL, C6-OXO-AHL, and C12-OXO-AHL was achieved over a period of up to 4 days. The AHLs and AOHLs in dialysates were concentrated with solid-phase extraction and quantified using LC-MS. Dialysate concentrations obtained for the AOHLs and AHLs ranged between 1 and 100 ppb (ng/mL) and varied between sampling days. This work demonstrates the initial use of microdialysis sampling to collect quorum sensing signaling chemicals during biofilm formation by a Gram-negative bacterial species.},
}
@article {pmid30741037,
year = {2019},
author = {Vadekeetil, A and Chhibber, S and Harjai, K},
title = {Efficacy of intravesical targeting of novel quorum sensing inhibitor nanoparticles against Pseudomonas aeruginosa biofilm-associated murine pyelonephritis.},
journal = {Journal of drug targeting},
volume = {},
number = {},
pages = {1-9},
doi = {10.1080/1061186X.2019.1574802},
pmid = {30741037},
issn = {1029-2330},
abstract = {Pseudomonas aeruginosa biofilm-associated pyelonephritis is a severe infection that can lead to mortality. There are no strategies that can effectively manage this infection since the pathogenesis is controlled by quorum sensing (QS) regulated virulence and recalcitrant biofilms. QS inhibitors (QSIs) are emerging therapeutics against such infections but are associated with cytotoxicity or low bioactivity. Hence, we developed novel quorum sensing inhibitor loaded nanoparticles (QSINPs) using the biopolymers, chitosan (CS) and dextran sulphate (DS) and were intravesically targeted against biofilm-associated murine pyelonephritis. The in-vivo targeting of QSINPs was confirmed by tracking the fluorescein isothiocyanate (FITC) tagged QSINPs in bladder and kidney of mice. On characterising, the QSINPs showed a size of 685.7 nm with a zeta potential of 37.9 and polydispersity index (PDI) of 0.5. Scanning electron microscopy (SEM) indicated spherical shape and bioactivity assays indicated QSI activity till 8 months. Fourier transform infra-red (FTIR) analysis indicated possibility of isothiocyanate bonding in CS with DS and with QSI. The QSINPs showed excellent in vitro antivirulence activity by reducing the virulence factors and biofilm of P. aeruginosa and in vivo therapeutic efficacy with ciprofloxacin (CIP). Hence, we propose a novel next-generation therapeutic and its appropriate targeting route against biofilm-associated pyelonephritis.},
}
@article {pmid30740751,
year = {2019},
author = {Marques, CNH and Nelson, SM},
title = {Pharmacodynamics of ciprofloxacin against Pseudomonas aeruginosa planktonic and biofilm-derived cells.},
journal = {Letters in applied microbiology},
volume = {68},
number = {4},
pages = {350-359},
doi = {10.1111/lam.13126},
pmid = {30740751},
issn = {1472-765X},
support = {//HEFCEQR/ ; //BSAC project grant/ ; },
abstract = {The influence of growth phase and state on the survival and recovery of Pseudomonas aeruginosa exposed to ciprofloxacin was investigated using batch culture grown planktonic cells and disaggregated biofilm populations. Biofilms were either nonantibiotic exposed or previously exposed to ciprofloxacin before disaggregation and subsequent challenge with ciprofloxacin. Viable counts showed that late stationary phase cells were tolerant to ciprofloxacin over 24 h exposure, while all other populations presented a biphasic killing pattern. In contrast, the metabolic activity of planktonic and biofilm-derived cells remained similar to controls during the initial 6 h of ciprofloxacin exposure, despite a significant reduction in viable cell numbers. A similar effect was observed when assessing the postantibiotic effect of 1 h ciprofloxacin exposure. Thus, although cell reduction occurred, the metabolic status of the cells remained unchanged. The recovery of disaggregated biofilm cells previously exposed to ciprofloxacin was significantly quicker than naïve biofilm cells, and this latter population's recovery was significantly slower than all planktonic populations. Results from this work have implications for our understanding of biofilm-related infections and their resilience to antimicrobial treatment. SIGNIFICANCE AND IMPACT OF THE STUDY: Removal of biofilms from surfaces and infection sites via disaggregation and induction of dispersion may reverse their antibiotic tolerant state. However, little is known of the recovery of the cells upon disaggregation from biofilms. Driven by this gap in knowledge we quantified the effect of ciprofloxacin on disaggregated biofilms of Pseudomonas aeruginosa, including those previously exposed to ciprofloxacin. Our results provide further insight into bacterial resilience, regrowth, and antimicrobial efficacy, as reduction in cell viability does not directly correlate with the metabolic activity of bacteria at the time of the exposure to antimicrobials. Thus, despite a perceived reduction in viability, the potential for cell persistence and regrowth remains and recovery is quicker upon subsequent exposure to antimicrobial, supporting the increase in resilience and recurrence of infections.},
}
@article {pmid30739982,
year = {2018},
author = {Pasternak, G and Greenman, J and Ieropoulos, I},
title = {Dynamic evolution of anodic biofilm when maturing under different external resistive loads in microbial fuel cells. Electrochemical perspective.},
journal = {Journal of power sources},
volume = {400},
number = {},
pages = {392-401},
doi = {10.1016/j.jpowsour.2018.08.031},
pmid = {30739982},
issn = {0378-7753},
abstract = {Appropriate inoculation and maturation may be crucial for shortening the startup time and maximising power output of Microbial Fuel Cells (MFCs), whilst ensuring stable operation. In this study we explore the relationship between electrochemical parameters of MFCs matured under different external resistance (Rext) values (50 Ω - 10 kΩ) using non-synthetic fuel (human urine). Maturing the biofilm under the lower selected Rext results in improved power performance and lowest internal resistance (Rint), whereas using higher Rext results in increased ohmic losses and inferior performance. When the optimal load is applied to the MFCs following maturity, dependence of microbial activity on original Rext values does not change, suggesting an irreversible effect on the biofilm, within the timeframe of the reported experiments. Biofilm microarchitecture is affected by Rext and plays an important role in MFC efficiency. Presence of water channels, EPS and precipitated salts is distinctive for higher Rext and open circuit MFCs. Correlation analysis reveals that the biofilm changes most dynamically in the first 5 weeks of operation and that fixed Rext lefts an electrochemical effect on biofilm performance. Therefore, the initial conditions of the biofilm development can affect its long-term structure, properties and activity.},
}
@article {pmid30739073,
year = {2019},
author = {Zhu, J and Liu, R and Cao, N and Yu, J and Liu, X and Yu, Z},
title = {Mycobacterial metabolic characteristics in a water meter biofilm revealed by metagenomics and metatranscriptomics.},
journal = {Water research},
volume = {153},
number = {},
pages = {315-323},
doi = {10.1016/j.watres.2019.01.032},
pmid = {30739073},
issn = {1879-2448},
abstract = {Mycobacteria represent one of the most persistent bacterial populations in drinking water distribution system (DWDS) biofilm communities; however, mycobacterial in situ metabolic profiles are largely unknown. In this study, the metabolic characteristics of mycobacteria in a household water meter biofilm were unveiled using a coupled metagenomic/metatranscriptomic approach. The water meter biofilm appeared to express nitrogenase genes (nifDKH) and a full complement of genes coding for several carbon-fixation pathways, especially the Calvin cycle, suggesting the CO2 sequestration and dinitrogen fixation potential of the biofilm. These findings indicate that it may be difficult to prevent the formation of DWDS biofilms simply by controlling the availability of organic carbon or nitrogen. The composite genome of mycobacteria (CG-M) was reconstructed based on the obtained omics data. CG-M shared similar genome phylogeny and virulence-factor profiles with Mycobacterium avium complex, suggesting that population CG-M might represent a member of mycobacteria with pathogenicity. According to the gene expression patterns, population CG-M showed the metabolic potential to assimilate CO2 via the Calvin cycle and/or anaplerotic reactions, and even to grow autotrophically with CO as the sole carbon and energy source. This suggests that organic carbon may not be a limiting factor for mycobacterial growth in DWDSs. Moreover, our results suggest that mycobacterial aromatic degradation is primarily achieved through the catechol meta-cleavage pathway, and biofilm mycobacteria could prefer phosphate as the phosphorus source.},
}
@article {pmid30735953,
year = {2019},
author = {Gong, CP and Luo, Y and Pan, YY},
title = {Novel synthesized zinc oxide nanoparticles loaded alginate-chitosan biofilm to enhanced wound site activity and anti-septic abilities for the management of complicated abdominal wound dehiscence.},
journal = {Journal of photochemistry and photobiology. B, Biology},
volume = {192},
number = {},
pages = {124-130},
doi = {10.1016/j.jphotobiol.2019.01.019},
pmid = {30735953},
issn = {1873-2682},
mesh = {*Abdominal Wound Closure Techniques ; Alginates ; Anti-Infective Agents, Local/*pharmacology ; Bacteria/drug effects ; *Biofilms ; Chitosan ; Humans ; Metal Nanoparticles/*chemistry ; Nanoparticles ; Surgical Wound Dehiscence/*drug therapy ; Wound Healing/*drug effects ; Zinc Oxide/chemistry ; },
abstract = {Wound dehiscence is a surgical complication and its management is inevitable because 25% to 35% of patients suffered from post laparotomy wound dehiscence. The excellent biodegradability and biocompatibility of chitosan and alginate have provided ample space for future developments in biomedical applications. Hence, the present work is directed towards the synthesis of robust biofilm made up of chitosan (CS), zinc oxide (ZnO) nanoparticles and Alginate (Alg). Chitosan and alginate were used for their pore forming ability, and ZnO is for its antibacterial action. The proposed biofilm was characterized with different characterization techniques such as Fourier Transform Infrared (FTIR) spectroscopy, UV-vis spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron microscopy (TEM) analyses. FTIR results inferred the strong interaction between the three components. The surface morphology of ZnO-CS/Alg. biofilm was exhibited as the spherical shaped nanoparticles which are firmly anchored on the polymer matrix. TEM analysis also confirmed the formation of biofilm. The XRD analysis confirmed the presence of ZnO in the biopolymer. The line broadening suggests that the crystallize size is in few nanometers. The average crystallite size was estimated as 50 nm using Scherrer formula. The antibacterial activity of the biofilm was successfully established against bacterial pathogens. Therefore, the developed materials have a potential play as antimicrobial role for the abdominal wound healing and biomedical fields.},
}
@article {pmid30735206,
year = {2019},
author = {Ding, Y and Zhou, Y and Yao, J and Xiong, Y and Zhu, Z and Yu, XY},
title = {Molecular evidence of a toxic effect on a biofilm and its matrix.},
journal = {The Analyst},
volume = {144},
number = {8},
pages = {2498-2503},
doi = {10.1039/c8an02512f},
pmid = {30735206},
issn = {1364-5528},
abstract = {Shewanella oneidensis MR-1 wild-type and a hyper-adhesive mutant CP2-1-S1 are used as model organisms and Cr(vi) is selected as a toxic chemical to study biofilm and toxic chemical interactions. Biofilms are cultured in a microfluidic device for in situ time-of-flight secondary ion mass spectrometry imaging. This approach is viable for studying biofilms' responses to antimicrobial resistance.},
}
@article {pmid30735113,
year = {2019},
author = {Staneviciute, E and Na'amnih, W and Kavaliauskas, P and Prakapaite, R and Ridziauskas, M and Kevlicius, L and Kirkliauskiene, A and Zabulis, V and Urboniene, J and Triponis, V},
title = {New in vitro model evaluating antiseptics' efficacy in biofilm-associated Staphylococcus aureus prosthetic vascular graft infection.},
journal = {Journal of medical microbiology},
volume = {68},
number = {3},
pages = {432-439},
doi = {10.1099/jmm.0.000939},
pmid = {30735113},
issn = {1473-5644},
mesh = {Anti-Infective Agents, Local/*pharmacology ; Biofilms/*drug effects ; Chlorhexidine/analogs &amp; derivatives/pharmacology ; Humans ; Povidone-Iodine/pharmacology ; Prostheses and Implants/*microbiology ; Prosthesis-Related Infections/prevention &amp; control ; Pyridines/pharmacology ; Staphylococcal Infections/prevention &amp; control ; Staphylococcus aureus/*drug effects ; },
abstract = {PURPOSE: To develop a new in vitro model of prosthetic vascular graft infection (PVGI) and evaluate antimicrobial and biofilm-disrupting efficacy of 0.1% octenidine dihydrochloride, 10% povidone-iodine and 0.02% chlorhexidine digluconate against biofilm-producing Staphylococcus aureus (S. aureus).<br><br>METHODOLOGY: The effect of antiseptics on the microscopic integrity and antimicrobial effect on S. aureus biofilms was tested by growing biofilms on glass coverslips, in the modified Lubbock chronic wound pathogenic biofilm (LCWPB) model and on the surface of vascular grafts using qualitive and quantitative methods as well as by scanning electron microscopy (SEM).<br><br>RESULTS: Chlorhexidine worked best on destroying the integrity of S. aureus biofilms (P=0.002). In the LCWPB model, octenidine and povidone-iodine eradicated all S. aureus colonies (from 1.79 × 109 c.f.u. ml-1 to 0). In the newly developed PVGI model, the grafts were successfully colonized with biofilms as seen in SEM images. All antiseptics demonstrated significant antimicrobial efficacy, decreasing colony counts by seven orders of magnitude (P=0.002). Octenidine was superior to povidone-iodine (P=0.009) and chlorhexidine (P=0.041).<br><br>CONCLUSION: We implemented an innovative in vitro model on S. aureus biofilms grown in different settings, including a clinically challenging situation of PVGI. The strongest antimicrobial activity against S. aureus biofilms, grown on prosthetic vascular grafts, was showed by 0.1% octenidine dihydrochloride. We suggest that combinational therapy of antiseptics between chlorhexidine with either povidone-iodine or octenidine dihydrochloride should be tested in further experiments. Despite the need of further studies, our findings of these in vitro experiments will assist the management of vascular graft infection in clinical cases.},
}
@article {pmid30734662,
year = {2019},
author = {Ashrafi, E and Allahyari, E and Torresi, E and Andersen, HR},
title = {Effect of slow biodegradable substrate addition on biofilm structure and reactor performance in two MBBRs filled with different support media.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-10},
doi = {10.1080/09593330.2019.1581261},
pmid = {30734662},
issn = {1479-487X},
abstract = {In this study, two moving-bed biofilm reactors (MBBR1 and MBBR2) filled with different size of carrier media (Kaldnes K1 and Kaldnes K1 micro, respectively) were subjected to soluble (sugar and sodium acetate (Ac)) substrate and mixture of soluble and particulate (particulate potato starch (PS)) substrate in a very high organic loading rate (12 kgCOD/m3·d) at different temperatures (26 and 15°C, in MBBR1 and MBBR2, respectively). The effects of carrier type and substrate on biofilm structure and reactor performance have been studied. Starch was removed by adsorption at the biofilm surface and hydrolyzed which caused substrate gradient in MBBR1, however, hydrolyzed uniformly within biofilm in MBBR2. The biofilm of MBBR1 was irregular due to filamentous structure growth due to the substrate gradient, while, it was regular in MBBR2 due to uniform distribution of substrate. The performance of both MBBRs in ammonium, COD and TN removal decreased significantly when the amount of small particles in the reactor increased owing to feeding by starch, which led to biomass density decline. The type of media affected the quantity and distribution of attached biomass, which in turn influenced the activity of specific microbial functional groups in the biofilm. The biofilm in MBBR2 was thicker and consequently nitrogen removal by denitrification was much higher. The lower temperature did not affect negatively the reactor performance in MBBR2.},
}
@article {pmid30733843,
year = {2019},
author = {Takenaka, S and Ohsumi, T and Noiri, Y},
title = {Evidence-based strategy for dental biofilms: Current evidence of mouthwashes on dental biofilm and gingivitis.},
journal = {The Japanese dental science review},
volume = {55},
number = {1},
pages = {33-40},
doi = {10.1016/j.jdsr.2018.07.001},
pmid = {30733843},
issn = {1882-7616},
abstract = {Therapeutic mouthwash (MW) is an adjunctive tool along with a regular oral hygiene routine of daily tooth brushing and daily flossing. Previous systematic reviews have demonstrated that it is effective against dental biofilm and gingival inflammation, for prevention of dental caries, and for managing one's bad breath condition according to the active ingredients. MWs prevent the microorganisms from bacterial adhesion that corresponds to the initial step in biofilm formation. This review summarized the current state of evidence such as anti-biofilm, anti-gingivitis and cariostatic properties of MWs by evaluating systematic reviews from the past six years. The anti-biofilm property has been proven to be effective, with strong evidence of three main clinical efficacies. The most commonly studied active agent was chlorhexidine gluconate (CHX), followed by essential oil (EO) and cetylpyridinium chloride. All the systematic reviews are in complete agreement that CHX and EO provide statistically significant improvements in terms of plaque and gingival indices. These effects have held up over the years as the number of studies has increased. While the use of fluoride MW is proven to be effective in improving the oral health of both children and adults, the quality of evidence is still regarded as low.},
}
@article {pmid30732464,
year = {2018},
author = {Etim, IN and Wei, J and Dong, J and Xu, D and Chen, N and Wei, X and Su, M and Ke, W},
title = {Mitigation of the corrosion-causing Desulfovibrio desulfuricans biofilm using an organic silicon quaternary ammonium salt in alkaline media simulated concrete pore solutions.},
journal = {Biofouling},
volume = {34},
number = {10},
pages = {1121-1137},
doi = {10.1080/08927014.2018.1547377},
pmid = {30732464},
issn = {1029-2454},
abstract = {Organic silicon quaternary ammonium salt (OSA), an environmentally friendly naturally occurring chemical, was used as a bacteriostatic agent against sulphate-reducing bacteria (SRB) on a 20SiMn steel surface in simulated concrete pore solutions (SCP). Four different media were used: No SRB (NSRB), No SRB and OSA (NSRB + OSA), With SRB (WSRB), With SRB and OSA (WSRB + OSA). After biofilm growth for 28 days, optimized sessile SRB cells survived at the high pH of 11.35 and as a result these cells caused the breakdown of the passive film due to the metabolic activities of the SRB. Corrosion prevention results showed that the OSA was effective in mitigating the growth of the sessile SRB cells and reduced corrosion in the SCP. These results were further confirmed by scanning electron microscope images, energy dispersive X-ray analysis, confocal-laser scanning microscopy, X-ray photoelectron spectroscopy and corrosion testing using electrochemical analysis.},
}
@article {pmid30731369,
year = {2019},
author = {Tang, B and Gong, T and Zhou, X and Lu, M and Zeng, J and Peng, X and Wang, S and Li, Y},
title = {Deletion of cas3 gene in Streptococcus mutans affects biofilm formation and increases fluoride sensitivity.},
journal = {Archives of oral biology},
volume = {99},
number = {},
pages = {190-197},
doi = {10.1016/j.archoralbio.2019.01.016},
pmid = {30731369},
issn = {1879-1506},
abstract = {OBJECTIVE: The goal of this study was to analyze the impact of cas3 gene on the biofilm formation and virulence gene expression in S. mutans, since our previous studies have found a connection between CRISPR/Cas systems and biofilm formation in S. mutans.<br><br>METHODS: The cas3 gene in-frame deletion strains of S. mutans UA159 was constructed by a two-step transformation procedure and the cas3 mutant strain was complemented in trans. The biofilm biomass was measured by crystal violet staining, and the synthesis of exopolysaccharides (EPS) was measured by the anthrone-sulfuric method. Biofilm analysis and structural imaging was using confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) assays. The fluorescence in situ hybridization (FISH) was used to analyze the spatiotemporal interactions between S. mutans and Streptococcus sanguinis. Fluoride sensitivity was determined using fluoride tolerance assays. The expression of biofilm formation related genes was evaluated by qRT-PCR.<br><br>RESULTS: Our results showed that S. mutans cas3 deletion strain formed less biofilm and became less competitive when it was co-cultured with S. sanguinis under fluoride treatment. The expression levels of virulence genes including vicR, gtfC, smu0630 and comDE were significantly downregulated.<br><br>CONCLUSIONS: The cas3 gene in S. mutans could regulate biofilm formation and fluoride resistance, consequently affecting S. mutans competitiveness in a dual-species biofilm model under fluoride treatment. These results also provide a potential strategy for enhancing fluoride specificity, with cas3 gene as a potential genetic target in the modulation of oral microecology and the treatment of dental caries.},
}
@article {pmid30731188,
year = {2019},
author = {Mohammadi, M and Masoumipour, F and Hassanshahian, M and Jafarinasab, T},
title = {Study the antibacterial and antibiofilm activity of Carum copticum against antibiotic-resistant bacteria in planktonic and biofilm forms.},
journal = {Microbial pathogenesis},
volume = {129},
number = {},
pages = {99-105},
doi = {10.1016/j.micpath.2019.02.002},
pmid = {30731188},
issn = {1096-1208},
abstract = {OBJECTIVES: Microbial biofilms has attracted interest in the recent years because they has become the most important cause of nosocomial infections. This study was aimed to examine the antibacterial activities of Carum copticum extracts on the development of microbial biofilms and planktonic form of six pathogenic bacteria.<br><br>METHODS: Antimicrobial activity of the crude extracts against the planktonic form of six pathogenic bacteria: Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii and Klebsiella pneumonia was evaluated by using the disc diffusion method. Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) values was determined by macro-broth dilution technique. Anti-biofilm effects were assessed by microtiter plate method. The chemical composition of the herbal extract was identified by GC-MS.<br><br>RESULTS: According to disc diffusion test (MIC and MBC) the ability of C. copticum extracts for inhibition of bacteria in planktonic form was confirmed. The best inhibitory effect of this plant on S. aureus and low inhibitory effect on A. baumannii in planktonic forms were observed. These extracts were efficient to inhibit biofilm structures and concentration of each extract has direct relation with inhibitory effect. The maximum and minimum inhibitory effects of C. copticum methanolic extract on biofilm formation were observed on A. baumannii (98%) and K. pneumoniae (19%) respectively.<br><br>CONCLUSION: The GC-MS analysis revealed that five active compounds were present in the extract of this plant. Data obtained, suggested that the C. copticum extracts applied as antimicrobial agents against these pathogens particularly in biofilm making.},
}
@article {pmid30729077,
year = {2019},
author = {Prasad, A and Devi, AT and Prasad, MNN and Zameer, F and Shruthi, G and Shivamallu, C},
title = {Phyto anti-biofilm elicitors as potential inhibitors of Helicobacter pylori.},
journal = {3 Biotech},
volume = {9},
number = {2},
pages = {53},
doi = {10.1007/s13205-019-1582-2},
pmid = {30729077},
issn = {2190-572X},
abstract = {Helicobacterpylori (H. pylori) infection is a global public health concern. Due to its high adaptability in various adverse environments (temperature, pH, adhesion, phenotypic forms), targeting the bacterium is quite challenging. Moreover, due to its high persistence, decreased patience compliance and emerging antibiotic resistance, researchers have been forced to search for novel candidates with lesser or no side effects. Hence, in the current study, phytobioactives have been screened for its anti-biofilm attributes against H.pylori. Gastric biopsy samples have been screened using confirmatory techniques (microbiological, biochemical and molecular) for their virulent and non-virulent biomarkers. Physico-nutritive parameters were standardized. H. pylori biofilms were assessed using microtitre plate assay. Biofilms' biomass and exopolysaccharide have been evaluated using crystal violet and ruthenium red staining, respectively. Anti-biofilm screening was performed using potent aqueous phytochemicals namely Acorus calamus, Colocasia esculenta and Vitex trifolia. The results indicated the confluent growth of the H. pylori biofilms confirmed through genotyping and grew best at 37 °C for 72 h at a pH of 7.5 on polystyrene plates. Further, among the phytochemicals tested, Acorus calamus exhibited the highest H. pylori anti-biofilm activity via a dose-dependent pattern. The overall observations of the study will pave way for newer approaches to understand and combat bacterial pathogenesis and will contribute towards better health and hygiene.},
}
@article {pmid30728810,
year = {2019},
author = {Yang, Y and Luo, M and Zhou, H and Li, C and Luk, A and Zhao, G and Fung, K and Ip, M},
title = {Role of Two-Component System Response Regulator bceR in the Antimicrobial Resistance, Virulence, Biofilm Formation, and Stress Response of Group B Streptococcus.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {10},
doi = {10.3389/fmicb.2019.00010},
pmid = {30728810},
issn = {1664-302X},
abstract = {Group B Streptococcus (GBS; Streptococcus agalactiae) is a leading cause of sepsis in neonates and pregnant mothers worldwide. Whereas the hyper-virulent serogroup III clonal cluster 17 has been associated with neonatal disease and meningitis, serogroup III ST283 was recently implicated in invasive disease among non-pregnant adults in Asia. Here, through comparative genome analyses of invasive and non-invasive ST283 strains, we identified a truncated DNA-binding regulator of a two-component system in a non-invasive strain that was homologous to Bacillus subtilis bceR, encoding the bceRSAB response regulator, which was conserved among GBS strains. Using isogenic knockout and complementation mutants of the ST283 strain, we demonstrated that resistance to bacitracin and the human antimicrobial peptide cathelicidin LL-37 was reduced in the ΔbceR strain with MICs changing from 64 and 256 μg/ml to 0.25 and 64 μg/ml, respectively. Further, the ATP-binding cassette transporter was upregulated by sub-inhibitory concentrations of bacitracin in the wild-type strain. Upregulation of dltA in the wild-type strain was also observed and thought to explain the increased resistance to antimicrobial peptides. DltA, an enzyme involved in D-alanylation during the synthesis of wall teichoic acids, which mediates reduced antimicrobial susceptibility, was previously shown to be regulated by the bceR-type regulator in Staphylococcus aureus. In a murine infection model, we found that the ΔbceR mutation significantly reduced the mortality rate compared to that with the wild-type strain (p < 0.01). Moreover, this mutant was more susceptible to oxidative stress compared to the wild-type strain (p < 0.001) and was associated with reduced biofilm formation (p < 0.0001). Based on 2-DGE and mass spectrometry, we showed that downregulation of alkyl hydroperoxide reductase (AhpC), a Gls24 family stress protein, and alcohol dehydrogenase (Adh) in the ΔbceR strain might explain the attenuated virulence and compromised stress response. Together, we showed for the first time that the bceR regulator in GBS plays an important role in bacitracin and antimicrobial peptide resistance, virulence, survival under oxidative stress, and biofilm formation.},
}
@article {pmid30728626,
year = {2019},
author = {Gupta, K and Singh, SP and Manhar, AK and Saikia, D and Namsa, ND and Konwar, BK and Mandal, M},
title = {Inhibition of Staphylococcus aureus and Pseudomonas aeruginosa Biofilm and Virulence by Active Fraction of Syzygium cumini (L.) Skeels Leaf Extract: In-Vitro and In Silico Studies.},
journal = {Indian journal of microbiology},
volume = {59},
number = {1},
pages = {13-21},
doi = {10.1007/s12088-018-0770-9},
pmid = {30728626},
issn = {0046-8991},
abstract = {Syzygium cumini L. Skeels (Myretacae family) is a native plant of the Indian subcontinent which has wide socio-economical importance and is well known for its ant diabetic activity. The present study aimed to investigate the antibiofilm activity of purified fraction (EA) from S. cumini leaf extract against P. aeruginosa and S. aureus. The EA did not show any effect on growth of P. aeruginosa and S. aureus at the concentration of 900 µg/ml. At this concentration EA showed biofilm inhibition up to 86 ± 1.19% (***P < 0.0001) and 86.40 ± 1.19% (***P < 0.0001) in P. aeruginosa and S. aureus respectively. SEM examination also confirmed the reduction in biofilm formation. Further EA also disrupted some virulence phenotypes in P. aeruginosa and S. aureus. Bioactive compounds detected by GC-MS showed their possible molecular interaction with RhlG/NADP active-site complex (PDB ID: 2B4Q), LasR-TP4 complex (PDB ID: 3JPU) and Pseudaminidase (PDB ID: 2W38) from P. aeruginosa. The in vitro biofilm inhibition, virulence factor inhibition and the mode of interaction of bioactive components in Syzygium cumini with QS proteins of bacteria reported in this study might be an affordable and effective alternative method of controlling quorum sensing/biofilm-associated infections.},
}
@article {pmid30727772,
year = {2019},
author = {Czerwonka, G and Gmiter, D and Guzy, A and Rogala, P and Jabłońska-Wawrzycka, A and Borkowski, A and Cłapa, T and Narożna, D and Kowalczyk, P and Syczewski, M and Drabik, M and Dańczuk, M and Kaca, W},
title = {A benzimidazole-based ruthenium(IV) complex inhibits Pseudomonas aeruginosa biofilm formation by interacting with siderophores and the cell envelope, and inducing oxidative stress.},
journal = {Biofouling},
volume = {35},
number = {1},
pages = {59-74},
doi = {10.1080/08927014.2018.1564818},
pmid = {30727772},
issn = {1029-2454},
abstract = {Pseudomonas aeruginosa biofilm-associated infections are a serious medical problem, and new compounds and therapies acting through novel mechanisms are much needed. Herein, the authors report a ruthenium(IV) complex that reduces P. aeruginosa PAO1 biofilm formation by 84%, and alters biofilm morphology and the living-to-dead cell ratio at 1 mM concentration. Including the compound in the culture medium altered the pigments secreted by PAO1, and fluorescence spectra revealed a decrease in pyoverdine. Scanning electron microscopy showed that the ruthenium complex did not penetrate the bacterial cell wall, but accumulated on external cell structures. Fluorescence quenching experiments indicated strong binding of the ruthenium complex to both plasmid DNA and bovine serum albumin. Formamidopyrimidine DNA N-glycosylase (Fpg) protein digestion of plasmid DNA isolated after ruthenium(IV) complex treatment revealed the generation of oxidative stress, which was further proved by the observed upregulation of catalase and superoxide dismutase gene expression.},
}
@article {pmid30727758,
year = {2019},
author = {Shah, S and Gaikwad, S and Nagar, S and Kulshrestha, S and Vaidya, V and Nawani, N and Pawar, S},
title = {Biofilm inhibition and anti-quorum sensing activity of phytosynthesized silver nanoparticles against the nosocomial pathogen Pseudomonas aeruginosa.},
journal = {Biofouling},
volume = {35},
number = {1},
pages = {34-49},
doi = {10.1080/08927014.2018.1563686},
pmid = {30727758},
issn = {1029-2454},
abstract = {Quorum sensing (QS), the communication signaling network, regulates biofilm formation and several virulence factors in Pseudomonas aeruginosa PAO1, a nosocomial opportunistic pathogen. QS is considered to be a challenging target for compounds antagonistic to virulent factors. Biologically synthesized silver nanoparticles (AgNPs) are reported as anti-QS and anti-biofilm drugs against bacterial infections. The present study reports on the synthesis and characterization of Piper betle (Pb) mediated AgNPs (Pb-AgNPs). The anti-QS activity of Pb-AgNPs against Chromobacterium violaceum and the potential effect of Pb-AgNPs on QS-regulated phenotypes in PAO1 were studied. FTIR analysis exhibited that Pb-AgNPs had been capped by phytochemical constituents of Pb. Eugenol is one of the active phenolic phytochemicals in Pb leaves, therefore molecular docking of eugenol-conjugated AgNPs on QS regulator proteins (LasR, LasI and MvfR) was performed. Eugenol-conjugated AgNPs showed considerable binding interactions with QS-associated proteins. These results provide novel insights into the development of phytochemically conjugated nanoparticles as promising anti-infective candidates.},
}
@article {pmid30726061,
year = {2019},
author = {Liu, F and He, D and Yu, Y and Cheng, L and Zhang, S},
title = {Quaternary Ammonium Salt-Based Cross-Linked Micelles to Combat Biofilm.},
journal = {Bioconjugate chemistry},
volume = {30},
number = {3},
pages = {541-546},
doi = {10.1021/acs.bioconjchem.9b00010},
pmid = {30726061},
issn = {1520-4812},
abstract = {Due to self-produced extracellular polymeric substances (EPS), biofilms are hard to eradicate by common antimicrobials. Herein, a new quaternary ammonium salt based cross-linked micelle (QAS@CM) was created to combat biofilms. The QAS@CM adsorbed first onto the biofilm surface through multicharged interaction, then penetrated the EPS in the form of nanoparticles and diffused throughout the films. By responding to the biofilm acid/lipase microenvironment, these nanoparticles would further break into quaternary ammonium oligomers and act as the polyvalent inhibitors to effectively destroy the established biofilm and kill the corresponding bacteria within it.},
}
@article {pmid30725258,
year = {2019},
author = {Xu, Y and Wang, C and Hou, J and Wang, P and You, G and Miao, L},
title = {Effects of cerium oxide nanoparticles on bacterial growth and behaviors: induction of biofilm formation and stress response.},
journal = {Environmental science and pollution research international},
volume = {26},
number = {9},
pages = {9293-9304},
doi = {10.1007/s11356-019-04340-w},
pmid = {30725258},
issn = {1614-7499},
support = {KYCX18_0636//the Postgraduate Research &amp; Practice Innovation Program of Jiangsu Province/ ; No.51722902//the National Natural Science Funds for Excellent Young Scholar/ ; No.51421006//the National Natural Science Funds for Creative Research Groups of China/ ; No. 91647206//the Key Program of National Natural Science Foundation of China/ ; BK20160038//the Outstanding Youth Fund of Natural Science Foundation of Jiangsu, China/ ; 2018B671X14//the Fundamental Research Funds for the Central Universities/ ; },
abstract = {In this paper, the effects of cerium oxide nanoparticles (CeO2 NPs) on the group bacterial behaviors were elaborated. After 36-h cultivation, the biofilm biomass was enhanced by the sub-lethal concentrations of 0.5 and 2 mg/L CeO2 NP exposure. Meanwhile, the promoted production of total amino acids in microbes further resulted in the increased surface hydrophobicity and percentage aggregation. To resist the CeO2 NPs stress, the biofilm exhibited a double-layer microstructure, with the protein (PRO) and living cells occupying the bottom, the polysaccharide (PS), and dead cells dominating the top. The bacterial diversity was highly suppressed and Citrobacter and Pseudomonas from the phylum of γ-Proteobacteria strongly dominated the biofilm, indicating the selective and enriched effects of CeO2 NPs on resistant bacteria. The stimulated inherent resistance of biofilm was reflected by the reduced adenosine triphosphate (ATP) content after 4 h exposure. The increased levels of reactive oxygen species (ROS) in the treatments of 8 h CeO2 NP exposure led to the upregulated quorum sensing signals of acylated homoserine lactone (AHL) and autoinducer 2 (AI-2), beneficial to mitigating the environmental disturbance of CeO2 NPs. These results provide evidences for the accelerating effects of CeO2 NPs on biofilm formation through oxidative stress, which expand the understanding of the ecological effects of CeO2 NPs.},
}
@article {pmid30724702,
year = {2019},
author = {Enaime, G and Baçaoui, A and Yaacoubi, A and Berzio, S and Wichern, M and Lübken, M},
title = {Packed-bed biofilm reactor for semi-continuous anaerobic digestion of olive mill wastewater: performances and COD mass balance analysis.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-13},
doi = {10.1080/09593330.2019.1578830},
pmid = {30724702},
issn = {1479-487X},
abstract = {In the present study, the treatability of olive mill wastewater (OMWW) using an anaerobic fixed bed biofilm reactor packed with granular activated carbon (GAC) and inoculated with non-acclimated biomass was performed in a semi-continuous mode under mesophilic conditions. Three organic loading rates (OLR) varied from 0.94 to 2.81 g COD/(L d) were applied. The results of batch adsorption tests on GAC and the experimental data from PBBR-GAC operation were used to set up a COD mass balance in order to investigate the effect of adsorption on the COD removal during the three anaerobic treatment steps. Despite the slight accumulation of volatile fatty acids (VFAs) during the second and the third steps, between 735 and 1135 mg COD/L (as acetic acid), a stable environment for methanogens was maintained for a period of 104 days. During the three steps, degradation levels were up to 80% of COD and 85% of phenolic compounds. An averaged specific biogas production of 1.77 LN/d and a methane (CH4) concentration of about 60%, corresponding to a CH4 yield of 0.31 L CH4produced/g CODdepleted, were reached at an OLR of 2.81 g COD/(L d). The results show that the COD mass balance was not closed during the first two steps, while in the third step, it could be around 96%. This finding suggests that the adsorption of organic substances on activated carbon occur just during the two first steps, while at 2.81 g COD/(L d) OLR no adsorption is occurring and the introduced COD becomes completely available for CH4 production.},
}
@article {pmid30719720,
year = {2019},
author = {Ramirez, T and Shrestha, A and Kishen, A},
title = {Inflammatory potential of monospecies biofilm matrix components.},
journal = {International endodontic journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/iej.13093},
pmid = {30719720},
issn = {1365-2591},
support = {//University of Toronto/ ; },
abstract = {AIM: To assess the inflammatory potential of biofilm matrix constituents of Enterococcus faecalis and Pseudomonas aeruginosa monospecies biofilms on macrophages.<br><br>METHODOLOGY: In vitro biofilms of E. faecalis and P. aeruginosa were grown (7 days) in aerobic and anaerobic conditions. The biofilm matrix components: exopolysaccharides (EPS) and extracellular DNA (eDNA) were extracted and quantified. The inflammatory potential of EPS and eDNA was assessed on macrophage cell lines (RAW 267.4) using nitric oxide (NO), and enzyme-linked immunosorbent assay for tumour necrosis factor (TNF-α) and interleukin-6 (IL-6) expressions. LPS from P. aeruginosa and planktonic bacteria were positive controls. One-way analysis of variance and the Tukey post hoc test were used for statistical analysis.<br><br>RESULTS: Extracted EPS from both biofilm strains was associated with higher levels than eDNA in both growth conditions (P < 0.05). The biofilm components had less inflammatory potential compared to planktonic bacteria and LPS. EPS produced higher levels of inflammatory response compared to eDNA for both strains (P < 0.05). IL-6 and TNF-α, and NO expression showed no difference for E. faecalis EPS (P ≥ 0.05). In contrast, P. aeruginosa EPS and eDNA had significant levels of IL-6 compared to TNF-α and NO (P < 0.05).<br><br>CONCLUSIONS: Monospecies biofilm matrix EPS and eDNA from the bacterial strains tested had the ability to induce a low-grade inflammatory response when compared to planktonic bacteria and LPS. This study highlights the potential of biofilm matrix/components, devoid of bacteria to induce low-grade chronic inflammation.},
}
@article {pmid30719328,
year = {2018},
author = {Frickmann, H and Klenk, C and Warnke, P and Redanz, S and Podbielski, A},
title = {Influence of Probiotic Culture Supernatants on In Vitro Biofilm Formation of Staphylococci.},
journal = {European journal of microbiology &amp; immunology},
volume = {8},
number = {4},
pages = {119-127},
doi = {10.1556/1886.2018.00022},
pmid = {30719328},
issn = {2062-509X},
abstract = {Background: The effects of cell-free culture supernatants of probiotic Lactobacillus rhamnosus GG and Streptococcus salivarius K12 on replication and biofilm forming of Staphylococcus aureus and S. epidermidis were assessed in vitro.<br><br>Methods: S. aureus and S. epidermidis strains were exposed to cell-free culture supernatants of L. rhamnosus GG and S. salivarius K12 at different concentrations starting at 0, 4, and 24 h after the onset of incubation. Bacterial amplification was measured on microplate readers, as well as biofilm growth after safranine staining. Scanning electron microscopy was performed for visualization of biofilm status.<br><br>Results: The S. salivarius K12 culture supernatant not only reduced or prevented the formation and maturation of fresh biofilms but even caused a reduction of preformed S. epidermidis biofilms. The L. rhamnosus GG culture supernatant did not show clear inhibitory effects regardless of concentration or time of addition of supernatant, and even concentration-depending promotional effects on the planktonic and biofilm growth of S. aureus and S. epidermidis were observed.<br><br>Conclusion: In particular, the inhibitory effects of the S. salivarius K12 culture supernatant on the formation of staphylococcal biofilms are of potential relevance for biofilm-associated diseases and should be further assessed by in vivo infection models.},
}
@article {pmid30718527,
year = {2019},
author = {Miao, J and Lin, S and Soteyome, T and Peters, BM and Li, Y and Chen, H and Su, J and Li, L and Li, B and Xu, Z and Shirtliff, ME and Harro, JM},
title = {Biofilm Formation of Staphylococcus aureus under Food Heat Processing Conditions: First Report on CML Production within Biofilm.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {1312},
doi = {10.1038/s41598-018-35558-2},
pmid = {30718527},
issn = {2045-2322},
abstract = {This study aimed to evaluate the Staphylococcus aureus biofilm formation and Nε-carboxymethyl-lysine generation ability under food heat processing conditions including pH (5.0-9.0), temperature (25 °C, 31 °C, 37 °C, 42 °C and 65 °C), NaCl concentration (10%, 15% and 20%, w/v) and glucose concentration (0.5%, 1%, 2%, 3%, 5%, 10%, w/v). S. aureus biofilm genetic character was obtained by PCR detecting atl, ica operon, sasG and agr. Biofilm biomass and metabolic activity were quantified with crystal violet and methyl thiazolyl tetrazolium staining methods. S. aureus biofilm was sensitive to food heat processing conditions with 37 °C, pH 7.0, 2% glucose concentration (w/v) and 10% NaCl concentration (w/v) were favorable conditions. Besides, free and bound Nε-carboxymethyl-lysine level in weak, moderate and strong biofilm were detected by optimized high performance liquid chromatography tandem mass spectrometry. Nε-carboxymethyl-lysine level in S. aureus biofilm possessed a significant gap between strong, moderate and weak biofilm strains. This investigation revealed the biological and chemical hazard of Staphylococcus aureus biofilm to food processing environment.},
}
@article {pmid30718304,
year = {2019},
author = {Kobayashi, K},
title = {Inactivation of cysL Inhibits Biofilm Formation by Activating the Disulfide Stress Regulator Spx in Bacillus subtilis.},
journal = {Journal of bacteriology},
volume = {201},
number = {8},
pages = {},
doi = {10.1128/JB.00712-18},
pmid = {30718304},
issn = {1098-5530},
abstract = {Bacillus subtilis forms biofilms in response to internal and external stimuli. I previously showed that the cysL deletion mutant was defective in biofilm formation, but the reason for this remains unidentified. CysL is a transcriptional activator of the cysJI operon, which encodes sulfite reductase, an enzyme involved in cysteine biosynthesis. Decreased production of sulfite reductase led to biofilm formation defects in the ΔcysL mutant. The ΔcysL mutation was suppressed by disrupting cysH operon genes, whose products function upstream of sulfite reductase in the cysteine biosynthesis pathway, indicating that defects in cysteine biosynthesis were not a direct cause for the defective biofilm formation observed in the ΔcysL mutant. The cysH gene encodes phosphoadenosine phosphosulfate reductase, which requires a reduced form of thioredoxin (TrxA) as an electron donor. High expression of trxA inhibited biofilm formation in the ΔcysL mutant but not in the wild-type strain. Northern blot analysis showed that trxA transcription was induced in the ΔcysL mutant in a disulfide stress-induced regulator Spx-dependent manner. On the basis of these results, I propose that the ΔcysL mutation causes phosphoadenosine phosphosulfate reductase to consume large amounts of reduced thioredoxin, inducing disulfide stress and activating Spx. The spx mutation restored biofilm formation to the ΔcysL mutant. The ΔcysL mutation reduced expression of the eps operon, which is required for exopolysaccharide production. Moreover, overexpression of the eps operon restored biofilm formation to the ΔcysL mutant. Taken together, these results suggest that the ΔcysL mutation activates Spx, which then inhibits biofilm formation through repression of the eps operon.IMPORTANCEBacillus subtilis has been studied as a model organism for biofilm formation. In this study, I explored why the cysL deletion mutant was defective in biofilm formation. I demonstrated that the ΔcysL mutation activated the disulfide stress response regulator Spx, which inhibits biofilm formation by repressing biofilm matrix genes. Homologs of Spx are highly conserved among Gram-positive bacteria with low G+C contents. In some pathogens, Spx is also reported to inhibit biofilm formation by repressing biofilm matrix genes, even though these genes and their regulation are quite different from those of B. subtilis Thus, the negative regulation of biofilm formation by Spx is likely to be well conserved across species and may be an appropriate target for control of biofilm formation.},
}
@article {pmid30718177,
year = {2019},
author = {Mathieu, L and Keraval, A and Declercq, NF and Block, JC},
title = {Assessment of a low-frequency ultrasound device on prevention of biofilm formation and carbonate deposition in drinking water systems.},
journal = {Ultrasonics sonochemistry},
volume = {52},
number = {},
pages = {41-49},
doi = {10.1016/j.ultsonch.2018.10.029},
pmid = {30718177},
issn = {1873-2828},
abstract = {A device generating low-frequency and low-intensity ultrasound waves was used for mitigating biofilm accumulation and scaling. Two systems were tested: a lab-scale plate heat exchanger operated with continuously recycled water and a continually fed flow-through drinking water pilot used for mimicking water circulation in pipes. Initial deposition of bacterial cells was not prevented by ultrasound wave treatment. However, whatever the tested system, both further calcium carbonate deposition and biofilm growth were markedly inhibited. Biofilms formed in reactors subjected to low-frequency and low-intensity ultrasound waves were weakly attached to the material. Even though the activity of bacteria was affected as shown by their lower cultivability, membrane permeability did not appear compromised. Ultrasound technology sounds very promising in both the mitigation of drinking water biofilm and carbonate accumulation.},
}
@article {pmid30717454,
year = {2019},
author = {Chatrath, A and Gangwar, R and Kumari, P and Prasad, R},
title = {In Vitro Anti-Biofilm Activities of Citral and Thymol Against Candida Tropicalis.},
journal = {Journal of fungi (Basel, Switzerland)},
volume = {5},
number = {1},
pages = {},
doi = {10.3390/jof5010013},
pmid = {30717454},
issn = {2309-608X},
abstract = {Candida tropicalis is an emerging non-albicans Candida species which is pathogenic to the immune-compromised humans, especially in tropical countries, including India. The acquired resistance of Candida species towards antifungal therapies is of major concern. Moreover, limited efficacy and dosage constraint of synthetic drugs have indicated the prerequisite of finding new and natural drugs for treatment. In the present study, we have compared the influence of citral and thymol on C. tropicalis and its biofilm along with expression levels of certain antifungal tolerance genes. The antifungal and anti-biofilm activities of the both were studied using 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide sodium salt (XTT) reduction assay, field emission scanning electron microscope (FE-SEM) and confocal laser scanning microscope (CLSM) and real-time reverse transcription polymerase chain reaction (RT-PCR) analysis. Citral and thymol have damaged the cells with distorted surface and less viability. Quantitative real-time PCR analysis showed augmented expression of the cell membrane biosynthesis genes including ERG11/CYT450 against citral and the cell wall related tolerance genes involving CNB1 against thymol thus, depicting their differential mode of actions.},
}
@article {pmid30717122,
year = {2019},
author = {Gabe, V and Kacergius, T and Abu-Lafi, S and Kalesinskas, P and Masalha, M and Falah, M and Abu-Farich, B and Melninkaitis, A and Zeidan, M and Rayan, A},
title = {Inhibitory Effects of Ethyl Gallate on Streptococcus mutans Biofilm Formation by Optical Profilometry and Gene Expression Analysis.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {3},
pages = {},
doi = {10.3390/molecules24030529},
pmid = {30717122},
issn = {1420-3049},
abstract = {This study aimed to test the effectiveness of ethyl gallate (EG) against S. mutans biofilm formation on solid surfaces (polystyrene, glass) and acidogenicity, and to examine the effect on expression of related genes. The biofilm that is formed by S. mutans bacteria was evaluated using colorimetric assay and optical profilometry, while the pH of the biofilm growth medium was measured with microelectrode. The expression of genes encoding glucan binding protein B (gbpB), glucosyltranferases B, -C, -D (gtfB, -C, -D) and F-ATPase (atpD, atpF) was assessed using a quantitative reverse transcription-polymerase chain reaction (RT-qPCR). It was revealed that all of the EG concentrations significantly suppressed S. mutans biofilm build-up on polystyrene and glass surfaces, and inhibited acidogenicity, in a dose-dependent manner, compared to the activity of untreated bacteria (p < 0.05). The highest concentration of EG (3.53 mM) reduced biofilm formation on polystyrene and glass surfaces by 68% and more than 91%, respectively, and prevented a decrease in pH levels by 95%. The RT-qPCR data demonstrate that the biofilm-producing bacteria treated with EG underwent significant gene expression changes involving the gtfC (a 98.6 increase in fold change), gtfB gene (a 47.5 increase in fold change) and the gbpB gene (a 13.8 increase in fold change). However, for the other genes tested (gtfD, atpD and atpF), the EG treatments did not produce significant expression change compared to the control. EG produced significant gene expression change in three genes-gtfC,gtfB, and gbpB; it has the capacity to inhibit S. mutans biofilm formation on solid surfaces (polystyrene, glass), as well as acidogenicity. Therefore, EG might be used as an antibiofilm and/or anticaries agent for oral formulations in order to reduce the prevalence of dental caries.},
}
@article {pmid30716574,
year = {2019},
author = {Wang, SY and Yang, XY and Meng, HS and Zhang, YC and Li, XY and Xu, J},
title = {Enhanced denitrification by nano ɑ-Fe2O3 induced self-assembled hybrid biofilm on particle electrodes of three-dimensional biofilm electrode reactors.},
journal = {Environment international},
volume = {125},
number = {},
pages = {142-151},
doi = {10.1016/j.envint.2019.01.060},
pmid = {30716574},
issn = {1873-6750},
abstract = {Three-dimensional biofilm electrode reactors (3D-BERs) represent a novel technology for wastewater denitrification. Formation of mature electroactive biofilm on particle electrodes is crucial to realize successful denitrification in 3D-BERs. However, long start-up time and low electroactivity of the biofilm formed on particle electrodes limit the further application of 3D-BERs in wastewater treatment. In this work, self-assembled hybrid biofilms (SAHB) was cultivated on granular activate carbon particle electrodes of the 3D-BER by assembling nano ɑ-Fe2O3 into the biofilm. ɑ-Fe2O3 was selected due to its high affinity to bacterial outer-membrane cytochromes, an important mediator for microbial electron transfer. SAHB formed on particle electrodes were characterized and the denitrification performance of 3D-BERs was also investigated. Results indicate that nano ɑ-Fe2O3 plays positive roles in the start-up of 3D-BER, which captures more microbes into SAHB and constructs thick biofilm on particle electrodes. Special microorganisms with denitrification function related with genera of Hydrogenophaga and Opitutus are distinctively enriched in SAHB. Nano ɑ-Fe2O3 induced SAHB exhibit superior denitrification performance compared to natural biofilm. The average denitrification rate increases from 0.62 mg total nitrogen/L/h for natural biofilm to 1.73 mg total nitrogen/L/h for SAHB, mainly ascribed to accelerated nitrites reduction. Our work provides new technical solution to enhance nitrates removal in 3D-BERs and brings deep insights into application of bio-electrochemical system in wastewater treatment.},
}
@article {pmid30714613,
year = {2019},
author = {Ghaziasgar, FS and Poursina, F and Hassanzadeh, A},
title = {Virulence factors, biofilm formation and antibiotic resistance pattern in Enterococcus faecalis and Enterococcus faecium isolated from clinical and commensal human samples in Isfahan, Iran.},
journal = {Annali di igiene : medicina preventiva e di comunita},
volume = {31},
number = {2},
pages = {154-164},
doi = {10.7416/ai.2019.2268},
pmid = {30714613},
issn = {1120-9135},
abstract = {BACKGROUND: The aim of this study was to determine and compare antibiotic resistance profile, biofilm formation ability and frequency of agg and ace genes in Enterococcus spp strains isolated from patients and healthy individuals.<br><br>METHODS: A total of 90 non-duplicate Enterococcus spp isolates were isolated from patients and healthy individuals. Antibiotic susceptibility pattern was determined by disk diffusion and E-test method. Virulence genes and two species of enterococci were determined by PCR amplification. The capacity of biofilm formation was also evaluated by microtiter plate technique.<br><br>RESULTS: E. faecalis was the predominant species among our clinical isolates (80%). The prevalence of agg and ace genes was 37.8% and 73.3% in clinical and 8.9% and 11.1% in &quot;healthy&quot; samples, respectively. The rate of Multiple Drug Resistant strains was 73.3% and 11.1% in clinical and &quot;healthy&quot; isolates, respectively. The ability of biofilm formation was significantly higher in clinical compared to &quot;healthy&quot; isolates (100% vs 75.6%, P < 0.05).<br><br>CONCLUSION: The frequency of ace and agg genes, antibiotic resistance and biofilm formation ability were significantly higher in clinical than in &quot;healthy&quot; isolates (P < 0.05). Existence of agg and ace genes, biofilm formation and antibiotic resistance among the healthy enterococci isolates has a special importance since, in case these strains spread through clinical environments or reach water sources, this issue can be considered as a risk factor for health and sanitation of societY.},
}
@article {pmid30714611,
year = {2019},
author = {Hoveida, L and Halaji, M and Rostami, S and Mobasherizadeh, S},
title = {Biofilm-producing ability of Staphylococcus spp isolated from different foodstuff products.},
journal = {Annali di igiene : medicina preventiva e di comunita},
volume = {31},
number = {2},
pages = {140-147},
doi = {10.7416/ai.2019.226},
pmid = {30714611},
issn = {1120-9135},
abstract = {BACKGROUND: In recent times, microbial-biofilm contamination has attracted considerable attention to the food industry. Pathogenic microorganisms can attach to food surfaces, grow on them, and form biofilm that cause an increase in the food safety risk. The mechanisms of biofilm formation have become an important issue in the food-processing industry, therefore, the aim of this study is to determine the biofilm formation and profiles of genes involved in biofilm production of staphylococci isolated from various foodstuff products.<br><br>MATERIAL AND METHODS: This cross-sectional study was conducted at some grocery stores and confectionaries from September 2015 to October 2016 in different areas of Isfahan, Iran. Staphylococcus spp were isolated from different foodstuff samples including sweet pastries, cakes and similar baked goods, dairy products such as cheese and yogurt, meat products such as sausages, and hamburgers. Standard microbiological methods were used for identification of Staphylococcus spp isolates. Antibiotic susceptibility pattern was determined by the disc diffusion method and icaA/icaD genes have been investigated as PCR target because of their role in the expression of intercellular adhesions involved in biofilm formation by S. aureus.<br><br>RESULTS: From a total of 194 different foodstuffs samples, 84 Staphylococcus spp were isolated. Out of the 84 Staphylococcus isolates, 95.2% (80/84) were positive to the ability of biofilm formation. Overall, 35.7% (30/84) and 26.2% (22/84) of Staphylococcus spp isolates were positive for icaA and icaD genes, respectively.<br><br>CONCLUSION: The results of the present study indicate that the remarkable rate of biofilm formation with the emergence of antibiotic resistance still remains a significant risk for the food safety, especially in foodstuff samples.},
}
@article {pmid30713773,
year = {2018},
author = {Mathlouthi, A and Pennacchietti, E and De Biase, D},
title = {Effect of Temperature, pH and Plasmids on In Vitro Biofilm Formation in Escherichia coli.},
journal = {Acta naturae},
volume = {10},
number = {4},
pages = {129-132},
pmid = {30713773},
issn = {2075-8251},
abstract = {Acid resistance (AR) in Escherichia coli is an important trait that protects this microorganism from the deleterious effect of low-pH environments. Reports on biofilm formation in E. coli K12 showed that the genes participating in AR were differentially expressed. Herein, we investigated the relationship between AR genes, in particular those coding for specific transcriptional regulators, and their biofilm-forming ability at the phenotypic level. The latter was measured in 96-well plates by staining the bacteria attached to the well, following 24-hour growth under static conditions, with crystal violet. The growth conditions were as follows: Luria Bertani (LB) medium at neutral and acidic pH, at 37°C or 25°C. We observed that the three major transcriptional regulators of the AR genes (gadX, gadE, gadW) only marginally affected biofilm formation in E. coli. However, a striking and novel finding was the different abilities of all the tested E. coli strains to form a biofilm depending on the temperature and pH of the medium: LB, pH 7.4, strongly supported biofilm formation at 25°C, with biofilm being hardly detectable at 37°C. On the contrary, LB, pH 5.5, best supported biofilm formation at 37°C. Moreover, we observed that when E. coli carried a plasmid, the presence of the plasmid itself affected the ability to develop a biofilm, typically by increasing its formation. This phenomenon varies from plasmid to plasmid, depends on growth conditions, and, to the best of our knowledge, remains largely uninvestigated.},
}
@article {pmid30713607,
year = {2018},
author = {Koohestani, M and Moradi, M and Tajik, H and Badali, A},
title = {Effects of cell-free supernatant of Lactobacillus acidophilus LA5 and Lactobacillus casei 431 against planktonic form and biofilm of Staphylococcus aureus.},
journal = {Veterinary research forum : an international quarterly journal},
volume = {9},
number = {4},
pages = {301-306},
doi = {10.30466/vrf.2018.33086},
pmid = {30713607},
issn = {2008-8140},
abstract = {This study was carried out to investigate the stability, antibacterial properties and biofilm removal potential of cell-free supernatant (CFS) of Lactobacillus acidophilus LA5 and Lactobacillus casei 431 against Staphylococcus aureus ATCC 25923. Antibacterial activity of both Lactobacillus strains was measured according to the agar spot method. The CFS was prepared by centrifugation of bacterial suspension at 4000 g for 10 min and the antimicrobial activity was measured using agar-well diffusion. The stability of CFSs during storage at 4.00 ± 2.00 °C and 25.00 ± 2.00 °C for a period of 4 weeks was measured based on the method of broth micro-dilution assay. Moreover, biofilm removal potential of CFS on 2-days-old biofilm of S. aureus developed on polystyrene and glass surfaces was also determined. The efficacy of CFS on bacterial biofilm established on the glass surface was also observed using fluorescence microscope. Results showed that inhibition zones of L. acidophilus (50.26 mm) were greater than L. casei (37.06 mm). The minimum inhibitory concentration of both CFSs remained stable (40 mg mL-1) during the storage for 28 days at 4.00 and 25.00 °C and storage temperature did not affect the antibacterial effectiveness of CFS. The addition of both CFSs significantly removed biofilm developed on both tested surfaces in a concentration-dependent manner. Biofilm removal property of L. acidophilus CFS was generally better than L. casei CFS which was confirmed by fluorescence microscope. The application of CFS of probiotic strains (i.e. Lactobacillus) as antibacterial and biofilm removal compounds could be very suitable to control the growth of food-borne pathogens.},
}
@article {pmid30713186,
year = {2018},
author = {Gulia, S and Bhatt, V and Shetty, M and Prasad, KD and Gupta, P},
title = {Effect of Type II Diabetes Mellitus, Candida Albicans and Streptococcus Mutans on the Biofilm Formation on Prosthetic Materials.},
journal = {The journal of contemporary dental practice},
volume = {19},
number = {12},
pages = {1538-1545},
pmid = {30713186},
issn = {1526-3711},
abstract = {AIM: To investigate the biofilm formation on Prosthetic materials as affected by type II diabetes mellitus, Candida albicans and Streptococcus mutans.<br><br>MATERIALS AND METHODS: Two types of saliva, natural saliva, and artificial saliva were collected and prepared respectively. The natural saliva was divided into diabetic and non-diabetic saliva. The artificial saliva was further divided into two groups, one inoculated with Streptococcus mutans and the second with Candida albicans. The 150 samples of various prosthetic materials were prepared using nickel-chromium alloy, ceramic, soft liner, tooth molding powder; heat cured the acrylic resin. The samples were then immersed in natural saliva and artificial saliva and studied for biofilm formation.<br><br>RESULTS: Diabetic saliva formed more biofilm than non-diabetic saliva. Streptococcus mutans were able to form more biofilm than Candida albicans in artificial saliva on constitutive androstane receptor (hCAR) and spinal length (SL). In Diabetic saliva, there was a significant difference in the biofilm formation seen between MC and NCA (p < 0.05). No biofilm was formed on hCAR in natural saliva (diabetic or non-diabetic). In artificial saliva inoculated with Candida albicans and streptococcus mutans there is a significant difference in the biofilm formation in all the materials except NCA.<br><br>CONCLUSION: Diabetic saliva has more potential to form biofilm than non-diabetic saliva. Also, Candida albicans and Streptococcus mutans both can form a biofilm on materials used with the maximum formation on hCAR. Smoother materials formed less biofilm than rougher surfaces like hCAR, PCM, SL.<br><br>CLINICAL SIGNIFICANCE: It is desirable for dental restorative materials to have a low susceptibility for accumulation and formation of biofilm as it may lead to pathologies such as dental caries, periodontal disease, peri-implantitis, etc. which are plaque-related. The most commonly used materials in prosthodontics have been used in the study to establish a direct relationship with the formation of biofilm, this, in turn, helps us to take the right call in choosing a material for a patient with an already compromised systemic condition.},
}
@article {pmid30712523,
year = {2019},
author = {Shah, FA},
title = {Micro-Raman Spectroscopy Reveals the Presence of Octacalcium Phosphate and Whitlockite in Association with Bacteria-Free Zones Within the Mineralized Dental Biofilm.},
journal = {Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada},
volume = {25},
number = {1},
pages = {129-134},
doi = {10.1017/S1431927618015659},
pmid = {30712523},
issn = {1435-8115},
mesh = {Aged ; Apatites ; Bacteria/*metabolism ; *Biofilms/growth &amp; development ; Calcium Phosphates/*analysis ; Crystallization ; Dental Calculus/chemistry ; Dental Implants/microbiology ; Dental Plaque/*chemistry ; Female ; Humans ; Microscopy, Electron, Scanning/methods ; Minerals/*analysis ; Peri-Implantitis/microbiology ; Spectrometry, X-Ray Emission/methods ; Spectrum Analysis, Raman/*methods ; },
abstract = {Through a correlative analytical approach encompassing backscattered electron scanning electron microscopy (BSE-SEM), energy dispersive X-ray spectroscopy (EDX), and micro-Raman spectroscopy, the composition of the mineralized biofilm around a dental implant, retrieved due to peri-implantitis, was investigated. The mineralized biofilm contains two morphologically distinct regions: (i) bacteria-containing zones (Bact+), characterized by aggregations of unmineralized and mineralized bacteria, and intermicrobial mineralization, and (ii) bacteria-free zones (Bact-), comprised mainly of randomly oriented mineral platelets. Intramicrobial mineralization, within Bact+, appears as smooth, solid mineral deposits resembling the morphologies of dental plaque bacteria. Bact- is associated with micrometer-sized Mg-rich mineral nodules. The Ca/P ratio of Bact+ is higher than Bact-. The inorganic phase of Bact+ is carbonated apatite (CHAp), while that of Bact- is predominantly octacalcium phosphate (OCP) and whitlockite (WL) inclusions. Compared with native bone, the inorganic phase of Bact+ (i.e., CHAp) exhibits higher mineral crystallinity, lower carbonate content, and lower Ca/P, C/Ca, Mg/Ca, and Mg/P ratios. The various CaPs found within the mineralized dental biofilm (CHAp, OCP, and WL) are related to the local presence/absence of bacteria. In combination with BSE-SEM and EDX, micro-Raman spectroscopy is a valuable analytical tool for nondestructive investigation of mineralized dental biofilm composition and development.},
}
@article {pmid30712376,
year = {2019},
author = {Li, C and Atlar, M and Haroutunian, M and Norman, R and Anderson, C},
title = {An investigation into the effects of marine biofilm on the roughness and drag characteristics of surfaces coated with different sized cuprous oxide (Cu2O) particles.},
journal = {Biofouling},
volume = {35},
number = {1},
pages = {15-33},
doi = {10.1080/08927014.2018.1559305},
pmid = {30712376},
issn = {1029-2454},
abstract = {Biofilms typically increase surface roughness and consequently the drag penalties on marine vessels. However, there is a lack of data regarding the time-dependent influence of biofilms on antifouling surface characteristics and frictional drag, especially for surface coatings with different sizes of cuprous oxide (Cu 2 O). In this study, a series of pressure drop measurements was carried out using flat plates coated with different sizes of Cu 2 O . The cuprous oxide-containing surfaces were deployed at sea for a period of six months to allow biofilm to develop. Surface microstructure and roughness analyses were carried out every six weeks using scanning electron microscopy and laser roughness surface profilometry. From the data, the added frictional drag caused by biofilm on ships was predicted, based on roughness function using Granville extrapolations. The analyses indicated that biofilms had significant impacts by altering the surface microstructure, resulting in higher frictional drag. However, due to the interaction between the biofilm and the physico-chemical properties of the substratum for panels coated with larger Cu 2 O , the roughness and drag measurement results were both found to have fluctuating increments.},
}
@article {pmid30712264,
year = {2019},
author = {Lai, YS and Ontiveros-Valencia, A and Coskun, T and Zhou, C and Rittmann, BE},
title = {Electron-acceptor loadings affect chloroform dechlorination in a hydrogen-based membrane biofilm reactor.},
journal = {Biotechnology and bioengineering},
volume = {},
number = {},
pages = {},
doi = {10.1002/bit.26945},
pmid = {30712264},
issn = {1097-0290},
abstract = {Chloroform (CF) can undergo reductive dechlorination to dichloromethane, chloromethane, and methane. However, competition for hydrogen (H2), the electron-donor substrate, may cause poor dechlorination when multiple electron acceptors are present. Common acceptors in anaerobic environments are nitrate (NO3-), sulfate (SO42-), and bicarbonate (HCO3-). We evaluated CF dechlorination in the presence of HCO3- at 1.56 e- Eq/m2 -day, then NO3- at 0.04-0.15 e- Eq/m2 -day, and finally NO3- (0.04 e- Eq/m2 -day) along with SO42- at 0.33 e- Eq/m2 -day in an H2 -based membrane biofilm reactor (MBfR). When the biofilm was initiated with CF-dechlorination conditions (no NO3- or SO42-), it yielded a CF flux of 0.14 e- Eq/m2 -day and acetate production via homoacetogenesis up to 0.26 e- eq/m2 -day. Subsequent addition of NO3- at 0.05 e- Eq/m2 -day maintained full CF dechlorination and homoacetogenesis, but NO3- input at 0.15 e- Eq/m2 -day caused CF to remain in the reactor's effluent and led to negligible acetate production. The addition of SO42- did not affect CF reduction, but SO42- reduction significantly altered the microbial community by introducing sulfate-reducing Desulfovibrio and more sulfur-oxidizing Arcobacter. Dechloromonas appeared to carry out CF dechlorination and denitrification, whereas Acetobacterium (homoacetogen) may have been involved with hydrolytic dechlorination. Modifications to the electron acceptors fed to the MBfR caused the microbial community to undergo changes in structure that reflected changes in the removal fluxes.},
}
@article {pmid30711652,
year = {2019},
author = {Wan, K and Zhang, M and Ye, C and Lin, W and Guo, L and Chen, S and Yu, X},
title = {Organic carbon: An overlooked factor that determines the antibiotic resistome in drinking water sand filter biofilm.},
journal = {Environment international},
volume = {125},
number = {},
pages = {117-124},
doi = {10.1016/j.envint.2019.01.054},
pmid = {30711652},
issn = {1873-6750},
abstract = {Biofilter, an essential water treatment process, is reported to be the harbor of bacterial antibiotic resistance genes (ARGs). Due to the oligotrophic characteristic of source water, filter biofilm is largely influenced by the concentration of organic carbon. The objective of this study was to investigate the effect of organic carbon concentration on shaping bacterial antibiotic resistome in filter biofilm. Our study was based on pilot-scale sand filters, and we investigated the antibiotic resistome using high-throughput qPCR. A total of 180 resistance genes from eight categories of antibiotics were detected in 15 biofilm samples of three sand filters. The results indicated that higher concentration of influent organic carbon led to lower diversity of bacterial community and richness of antibiotic resistance genes (ARGs) in biofilm. We discovered a negative correlation (p ≤ 0.01) between the richness of ARGs and the corresponding TOC level. Moreover, the absolute abundance of ARGs was positively correlated (p ≤ 0.05) with the abundance of 16S rRNA gene and was determined by the organic carbon concentration. Sand filters with gradient influent organic carbon concentration led to the formation of different antibiotic resistomes and canonical correspondence analysis (CCA) indicated that difference in bacterial community composition was likely the main reason behind this difference. We also observed a similar trend in the relative abundance of ARGs, which increased with the depth of sand filters. However, this trend was more pronounced in filters with low organic carbon concentrations. Overall, this study revealed that the organic carbon concentration determined the absolute abundance of ARGs and also shaped the diversity and relative abundance of ARGs in drinking water sand filters. These results may provide new insights into the mechanism of persistent bacterial antibiotic resistance in drinking water treatment.},
}
@article {pmid30710814,
year = {2019},
author = {Wang, T and Wang, X and Yuan, L and Luo, Z and Kwame Indira, H},
title = {Start-up and operational performance of Anammox process in an anaerobic baffled biofilm reactor (ABBR) at a moderate temperature.},
journal = {Bioresource technology},
volume = {279},
number = {},
pages = {1-9},
doi = {10.1016/j.biortech.2019.01.114},
pmid = {30710814},
issn = {1873-2976},
abstract = {A lab-scale anaerobic baffled biofilm reactor (ABBR) was used as a novel reactor to start up Anammox process at a moderate temperature around 20 °C and an innovative filling module was adopted as support material. Quick start-up of Anammox process from the aerobic activated sludge was achieved after 47 days operation. The max nitrogen loading rate and nitrogen removing rate attained 1.00 kg N m-3 d-1 and 0.90 kg N m-3 d-1 after 161 days operation. Scanning electron microscope photographs showed that the structure as well as the states of the micro-aggregates (micro-aggregates sticking on a non-woven fiber, entangling non-woven fibers and enwrapped by non-woven fibers) enhanced biomass retention for Anammox bacteria. Microbial community analysis showed that Anammox bacteria were effectively enriched with Candidatus Brocadia, Candidatus Jettenia and Candidatus Kuenenia being the main Anammox species in the mature biofilms. This contributed to the excellent Anammox operation performance at the moderate temperature.},
}
@article {pmid30709828,
year = {2019},
author = {Allen, R and Rittmann, BE and Curtiss, R},
title = {Axenic Biofilm Formation and Aggregation by Synechocystis sp. Strain PCC 6803 Are Induced by Changes in Nutrient Concentration and Require Cell Surface Structures.},
journal = {Applied and environmental microbiology},
volume = {85},
number = {7},
pages = {},
doi = {10.1128/AEM.02192-18},
pmid = {30709828},
issn = {1098-5336},
abstract = {Phototrophic biofilms are key to nutrient cycling in natural environments and bioremediation technologies, but few studies describe biofilm formation by pure (axenic) cultures of a phototrophic microbe. The cyanobacterium Synechocystis sp. strain PCC 6803 (here Synechocystis) is a model microorganism for the study of oxygenic photosynthesis and biofuel production. We report here that wild-type (WT) Synechocystis caused extensive biofilm formation in a 2,000-liter outdoor nonaxenic photobioreactor under conditions attributed to nutrient limitation. We developed a biofilm assay and found that axenic Synechocystis forms biofilms of cells and extracellular material but only when cells are induced by an environmental signal, such as a reduction in the concentration of growth medium BG11. Mutants lacking cell surface structures, namely type IV pili and the S-layer, do not form biofilms. To further characterize the molecular mechanisms of cell-cell binding by Synechocystis, we also developed a rapid (8-h) axenic aggregation assay. Mutants lacking type IV pili were unable to aggregate, but mutants lacking a homolog to Wza, a protein required for type 1 exopolysaccharide export in Escherichia coli, had a superbinding phenotype. In WT cultures, 1.2× BG11 medium induced aggregation to the same degree as 0.8× BG11 medium. Overall, our data support that Wza-dependent exopolysaccharide is essential to maintain stable, uniform suspensions of WT Synechocystis cells in unmodified growth medium and that this mechanism is counteracted in a pilus-dependent manner under altered BG11 concentrations.IMPORTANCE Microbes can exist as suspensions of individual cells in liquids and also commonly form multicellular communities attached to surfaces. Surface-attached communities, called biofilms, can confer antibiotic resistance to pathogenic bacteria during infections and establish food webs for global nutrient cycling in the environment. Phototrophic biofilm formation is one of the earliest phenotypes visible in the fossil record, dating back over 3 billion years. Despite the importance and ubiquity of phototrophic biofilms, most of what we know about the molecular mechanisms, genetic regulation, and environmental signals of biofilm formation comes from studies of heterotrophic bacteria. We aim to help bridge this knowledge gap by developing new assays for Synechocystis, a phototrophic cyanobacterium used to study oxygenic photosynthesis and biofuel production. With the aid of these new assays, we contribute to the development of Synechocystis as a model organism for the study of axenic phototrophic biofilm formation.},
}
@article {pmid30708330,
year = {2019},
author = {Zheng, Y and Huang, Y and Xia, A and Qian, F and Wei, C},
title = {A rapid inoculation method for microalgae biofilm cultivation based on microalgae-microalgae co-flocculation and zeta-potential adjustment.},
journal = {Bioresource technology},
volume = {278},
number = {},
pages = {272-278},
doi = {10.1016/j.biortech.2019.01.083},
pmid = {30708330},
issn = {1873-2976},
abstract = {Due to the small size, similar density to water, cells inoculating onto the solid carrier is a major challenge for microalgae biofilm cultivation. To reduce biofilm inoculation time, A. falcatus with long stripe were chosen as the bond linking with the main microalgae cells forming microalgae-microalgae co-flocculation by bridging and twining. The optimal matching species were S. obliquus and A. falcatus with the volume ratio of 4-1. By changing the zeta-potential of the microalgae-microalgae co-flocculation to positive and negative through pH regulating, the inoculation time was significantly shorted from 4 h to 1.5 min due to the charge neutralization. Fortunately, the added A. falcatus and pH regulation has no negative effects on biofilm growth. Inversely, the porous microstructure of microalgae-microalgae co-flocculation improve the transfer efficiency of nutrients, resulting a 90.15% increase on biomass productivity (229.15 g m-2) comparing to pure microalgae species.},
}
@article {pmid30708091,
year = {2019},
author = {Eslami, LM},
title = {The Comparison of Intracanal Medicaments, Diode Laser and Photodynamic Therapy on Removing the Biofilm of Enterococcus faecalis and Candida Albicans in the Root Canal System (Ex-vivo Study).},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.pdpdt.2019.01.033},
pmid = {30708091},
issn = {1873-1597},
abstract = {BACKGROUND AND AIM: Long term success in endodontic therapy is attributed to removal and debridement of intracanal microorganisms. The aim of this study was to compare the antimicrobial effects calcium hydroxide (Ca(OH)2), triple antibiotic paste (TAP), photodynamic therapy(PDT), toluidine blue(TOL), light emitting diode (LED) and 940 nm diode laser (DL) on the biofilm of Enterococcus faecalis and Candida albicans in the root canal system of ex-vivo human teeth.<br><br>MATERIALS &amp; METHODS: 84 intact, uniradicular, extracted human premolar teeth were prepared and the apical foramina were sealed with glass ionomer.The samples were transformed to microtubes containing sterile BHI and were sterilized. After incubation of E. faecalis and C. albicans into the canals, the samples were kept in an incubator for 8 weeks to form the biofilm. Then the samples were randomly divided into 7 groups of 12, including: control and groups treated with Ca(OH)2,TAP, TOl, LED, PDT, and DL. Then the samples were fixed, gold coated and observed under scanning electron microscope (SEM).<br><br>RESULT: Significant reductions in biofilm thickness were noted in TAP,PDT and LED (P < 0.05). The greatest reduction in biofilm thickness was seen in TAP; however, the differences between TAP and PDT and LED were not significant (P > 0.05).<br><br>CONCLUSION: Since one of the main purposes in root canal therapy is to eliminate the bacteria, this study showed that the application of TAP, PDT, and LED exposure lead to least biofilm thickness.},
}
@article {pmid30707339,
year = {2019},
author = {Inácio, CP and de Araújo, PSR and Brayner, FA and Alves, LC and Veras, DL and Neves, RP},
title = {Invasive Candida tropicalis Infection Caused by Catheter Biofilm in a Patient with Tongue Cancer.},
journal = {Mycopathologia},
volume = {184},
number = {2},
pages = {345-346},
doi = {10.1007/s11046-018-0316-z},
pmid = {30707339},
issn = {1573-0832},
support = {140352/2015-5//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; },
abstract = {Systemic infections due to Candida tropicalis are conditions which can frequently lead to death. The aim of this report is to describe the features of C. tropicalis biofilm in a patient with catheter-associated fungemia.},
}
@article {pmid30707032,
year = {2019},
author = {Hart, JW and Waigh, TA and Lu, JR and Roberts, IS},
title = {Microrheology and Spatial Heterogeneity of Staphylococcus aureus Biofilms Modulated by Hydrodynamic Shear and Biofilm-Degrading Enzymes.},
journal = {Langmuir : the ACS journal of surfaces and colloids},
volume = {35},
number = {9},
pages = {3553-3561},
doi = {10.1021/acs.langmuir.8b04252},
pmid = {30707032},
issn = {1520-5827},
abstract = {Particle tracking microrheology was used to investigate the viscoelasticity of Staphylococcus aureus biofilms grown in microfluidic cells at various flow rates and when subjected to biofilm-degrading enzymes. Biofilm viscoelasticity was found to harden as a function of shear rate but soften with increasing height away from the attachment surface in good agreement with previous bulk results. Ripley's K-function was used to quantify the spatial distribution of the bacteria within the biofilm. For all conditions, biofilms would cluster as a function of height during growth. The effects of proteinase K and DNase-1 on the viscoelasticity of biofilms were also investigated. Proteinase K caused an order of magnitude change in the compliances, softening the biofilms. However, DNase-1 was found to have no significant effects over the first 6 h of development, indicating that DNA is less important in biofilm maintenance during the initial stages of growth. Our results demonstrate that during the preliminary stages of Staphylococcus aureus biofilm development, column-like structures with a vertical gradient of viscoelasticity are established and modulated by the hydrodynamic shear caused by fluid flow in the surrounding environment. An understanding of these mechanical properties will provide more accurate insights for removal strategies of early-stage biofilms.},
}
@article {pmid30706947,
year = {2019},
author = {Flynn, PB and Graham, WG and Gilmore, BF},
title = {Acinetobacter baumannii biofilm biomass mediates tolerance to cold plasma.},
journal = {Letters in applied microbiology},
volume = {68},
number = {4},
pages = {344-349},
doi = {10.1111/lam.13122},
pmid = {30706947},
issn = {1472-765X},
support = {BB/P008496/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; },
abstract = {Acinetobacter baumannii is an intrinsically multidrug-resistant pathogen that, when existing as a biofilm, confers increased environmental tolerance to desiccation, nutrient starvation as well as increased tolerance to antimicrobials. Outbreaks of A. baumannii infections within the clinical setting are often associated with the biofilm phenotype. This study investigates the role of biofilm biomass in A. baumannii susceptibility to exposure to a kilohertz-driven, in-house-designed, cold plasma jet, through the examination of cold plasma treatment efficacy in A. baumannii biofilms grown over various times for up to 72 h. For biofilms grown for 24, 48 and 72 h, D values were 19·32 ± 2·71, 29·18 ± 3·15 and 24·70 ± 3·07 s respectively. Monitoring A. baumannii biofilm biomass over these time periods revealed that the greatest biomass was observed at 48 h with the lowest biofilm biomass at 24 h growth. Enumeration of viable biofilm colony counts at each time point was comparable. Scanning electron microscopy images of plasma-treated biofilms revealed extensive surface damage of A. baumannii cells. These results describe the role of biomass in mediating A. baumannii biofilm susceptibility to cold plasma treatment, implicating the biofilm matrix as a protective barrier to the antimicrobial effects of cold plasma. SIGNIFICANCE AND IMPACT OF THE STUDY: Acinetobacter baumannii biofilm formation results in increased environmental and antimicrobial tolerance and resistance compared to the planktonic phenotype. Cold plasma technology is increasingly investigated as a new tool for decontamination of biofilm-contaminated surfaces, especially those found in the clinical setting. This new technology presents a promising approach to the remediation of surfaces contaminated by biofilms. This study identifies the role played by A. baumannii biofilm biomass in mediating tolerance and susceptibility to cold plasma treatment. This work demonstrates that increased biofilm biomass reduces the efficacy of antimicrobial species generated by cold plasma, resulting in greater tolerance to plasma exposure.},
}
@article {pmid30706343,
year = {2019},
author = {Martínez-García, S and Ortiz-García, CI and Cruz-Aguilar, M and Zenteno, JC and Murrieta-Coxca, JM and Pérez-Tapia, SM and Rodríguez-Martínez, S and Cancino-Diaz, ME and Cancino-Diaz, JC},
title = {Competition/antagonism associations of biofilm formation among Staphylococcus epidermidis Agr groups I, II, and III.},
journal = {Journal of microbiology (Seoul, Korea)},
volume = {57},
number = {2},
pages = {143-153},
doi = {10.1007/s12275-019-8322-5},
pmid = {30706343},
issn = {1976-3794},
mesh = {Animals ; Bacterial Proteins/*genetics ; Biofilms/*growth &amp; development ; Catheter-Related Infections/microbiology ; DNA, Bacterial/genetics ; Disease Models, Animal ; Female ; Gene Expression Regulation, Bacterial/*genetics ; Genes, Bacterial/*genetics ; Genotype ; Humans ; Mice ; Mice, Inbred BALB C ; Multilocus Sequence Typing ; Operon ; Quorum Sensing ; Skin/microbiology ; Staphylococcal Infections/microbiology ; Staphylococcus epidermidis/*genetics/growth &amp; development/isolation &amp; purification/*physiology ; Trans-Activators/*classification/*genetics ; },
abstract = {Staphylococci have quorum-sensing (QS) systems that enable cell-to-cell communication, as well as the regulation of numerous colonization and virulence factors. The accessory gene regulator (Agr) operon is one of the Staphylococcus genus QS systems. Three groups (I, II, and III) are present in Staphylococcus epidermidis Agr operon. To date, it is unknown whether Agr groups can interact symbiotically during biofilm development. This study analyzed a symbiotic association among Agr groups during biofilm formation in clinical and commensal isolates. Different combinations among Agr group isolates was used to study biofilm formation in vitro and in vivo (using a mouse catheter-infection model). The analysis of Agr groups were also performed from samples of human skin (head, armpits, and nostrils). Different predominant coexistence was found within biofilms, suggesting symbiosis type. In vitro, Agr I had a competition with Agr II and Agr III. Agr II had a competition with Agr III, and Agr II was an antagonist to Agr I and III when the three strains were combined. In vivo, Agr II had a competition to Agr I, but Agr I and II were antagonists to Agr III. The associations found in vitro and in vivo were also found in different sites of the skin. Besides, other associations were observed: Agr III antagonized Agr I and II, and Agr III competed with Agr I and Agr II. These results suggest that, in S. epidermidis, a symbiotic association of competition and antagonism occurs among different Agr groups during biofilm formation.},
}
@article {pmid30706301,
year = {2019},
author = {Bino, E and Lauková, A and Ščerbová, J and Kubašová, I and Kandričáková, A and Strompfová, V and Miltko, R and Belzecki, G},
title = {Fecal coagulase-negative staphylococci from horses, their species variability, and biofilm formation.},
journal = {Folia microbiologica},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12223-019-00684-5},
pmid = {30706301},
issn = {1874-9356},
support = {2/0006/17//VEGA, Slovakia/ ; 2/0012/16//VEGA Slovakia/ ; },
abstract = {The intestinal microbiota has enormous impact on the health and performance of horses. Staphylococci belong in the phylum Firmicutes, and their occurrence, especially of methicillin-resistant strains and species, has been reported in horses previously. Moreover, biofilm formation is one of the virulence factors; it has been not completely studied in fecal coagulase-negative staphylococci (CoNS) from horses. Therefore, this study was focused on biofilm formation by various species of fecal CoNS from horses because it has been never reported before. In addition, their antibiotic profile was tested. Horses (42) of various breeds from Slovakia/Poland were sampled. Variability in the species of CoNS was detected in feces of horses. Thirty-two strains were identified by using the MALDI-TOF system and classified into nine species and three subspecies of CoNS: Staphylococcus capitis, S. cohnii subsp. cohnii, S. cohnii subsp. urealyticus, S. cohnii subsp. casei, S. epidermidis, S. haemolyticus, S. pasteuri, S. sciuri, S. vitulinus, S. warneri, and S. xylosus. The most frequent species was S. vitulinus. Twenty-two strains showed high biofilm production; 10 strains showed low-grade biofilm production. The highest biofilm formation was measured in the species S. xylosus. Eleven strains (of 32) were methicillin-resistant; the others were susceptible to methicillin.},
}
@article {pmid30704099,
year = {2019},
author = {Cadavid, E and Echeverri, F},
title = {The Search for Natural Inhibitors of Biofilm Formation and the Activity of the Autoinductor C6-AHL in Klebsiella pneumoniae ATCC 13884.},
journal = {Biomolecules},
volume = {9},
number = {2},
pages = {},
doi = {10.3390/biom9020049},
pmid = {30704099},
issn = {2218-273X},
abstract = {Human nosocomial infections are common around the world. One of the main causes is the bacteria Klebsiella pneumoniae, which shows high rates of resistance to antibiotics. Thus, drugs with novel mechanisms of action are needed. In this work, we report the effects of various natural substances on the formation of biofilm in Klebsiella pneumoniae, as well as its stability. The effect of the molecules on the growth of K. pneumoniae was initially determined by measuring the optical density. The modification of the biofilm, the changes relating to its resistance, the effects on the bacterial adhesion to the urethral catheter and its antagonist role the hexanoyl-homoserinelactone were assessed by crystal violet, as well as by microscopy. The best effects were obtained with 3-methyl-2(5H)-furanone and 2´-hydroxycinnamic acid, which inhibited the formation of biofilm by 67.38% and 65.06%, respectively. Additionally, the remaining biofilm formed was more susceptible to gentamicin. Through microscopy examination, there were evident changes in the biofilm and adherence on the polyvinyl chloride (PVC) urethral catheter. Besides, 3-methyl-2(5H)-furanone inhibited the biofilm-forming effect of the autoinducer hexanoyl-homoserinelactone. Thus, these molecules could be developed as supplemental of antibiotics.},
}
@article {pmid30704020,
year = {2019},
author = {Benzaid, C and Belmadani, A and Djeribi, R and Rouabhia, M},
title = {The Effects of Mentha × piperita Essential Oil on C. albicans Growth, Transition, Biofilm Formation, and the Expression of Secreted Aspartyl Proteinases Genes.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {1},
pages = {},
doi = {10.3390/antibiotics8010010},
pmid = {30704020},
issn = {2079-6382},
abstract = {The rise in resistance and changes in the spectrum of Candida infections have generated enormous interest in developing new antifungal drugs using natural molecules such as plant essential oils (EOs). Antimicrobial activity against foodborne pathogenic and spoilage microorganisms has been reported for EOs. The goal of this study was to assess the effect of Mentha × piperita essential oil (EO) on C. albicans growth, transition (change from blastospore to hyphae forms), and biofilm formation as well as on the expression of certain virulent genes. We show that whole EO and its vapor attenuated the yeast's growth, compared to that in the control. The effect of the EO was comparable to that of amphotericin-B (AmB). The EO and its vapor significantly decreased the morphological changes of C. albicans, reduced biofilm formation, and disrupted mature C. albicans biofilms. The effect produced by whole EO on biofilm formation/disruption was notably comparable to that observed with AmB. Exposure of C. albicans to EO and its vapor downregulated the expression of various genes, such as secreted aspartyl proteinases (SAP 1, 2, 3, 9, 10) and hyphal wall protein 1 (HWP1). Altogether, these results provide new insight into the efficacy of Mentha × piperita EO against C. albicans and suggest the potential of Mentha × piperita EO for use as an antifungal therapy in multiple applications.},
}
@article {pmid30703118,
year = {2019},
author = {Dangel, ML and Dettmann, JC and Haßelbarth, S and Krogull, M and Schakat, M and Kreikemeyer, B and Fiedler, T},
title = {The 5'-nucleotidase S5nA is dispensable for evasion of phagocytosis and biofilm formation in Streptococcus pyogenes.},
journal = {PloS one},
volume = {14},
number = {1},
pages = {e0211074},
doi = {10.1371/journal.pone.0211074},
pmid = {30703118},
issn = {1932-6203},
abstract = {5'-nucleotidases are widespread among all domains of life. The enzymes hydrolyze phosphate residues from nucleotides and nucleotide derivatives. In some pathobiontic bacteria, 5'-nucleotidases contribute to immune evasion by dephosphorylating adenosine mono-, di-, or tri-phosphates, thereby either decreasing the concentration of pro-inflammatory ATP or increasing the concentration of anti-inflammatory adenosine, both acting on purinergic receptors of phagocytic cells. The strict human pathogen Streptococcus pyogenes expresses a surface-associated 5'-nucleotidase (S5nA) under infection conditions that has previously been discussed as a potential virulence factor. Here we show that deletion of the S5nA gene does not significantly affect growth in human blood, evasion of phagocytosis by neutrophils, formation of biofilms and virulence in an infection model with larvae of the greater wax moth Galleria mellonella in S. pyogenes serotypes M6, M18 and M49. Hence, the surface-associated 5'-nucleotidase S5nA seems dispensable for evasion of phagocytosis and biofilm formation in S. pyogenes.},
}
@article {pmid30702944,
year = {2019},
author = {Aly, MA and Reimhult, E and Kneifel, W and Domig, KJ},
title = {Characterization of Biofilm Formation by Cronobacter spp. Isolates of Different Food Origin under Model Conditions.},
journal = {Journal of food protection},
volume = {82},
number = {1},
pages = {65-77},
doi = {10.4315/0362-028X.JFP-18-036},
pmid = {30702944},
issn = {1944-9097},
abstract = {Cronobacter spp. are opportunistic human pathogens that cause serious diseases in neonates and immunocompromised people. Owing to their biofilm formation on various surfaces, both their detection and their removal from production plants constitute a major challenge. In this study, food samples were randomly collected in Austria and examined for the presence of Cronobacter spp. Presumptive isolates were identified by a polyphasic approach. Five percent of the samples were positive for C. sakazakii and 2.4% for C. dublinensis. Individual growth of the isolates was characterized based on lag time, growth rate, and generation time. During an incubation period of 6 to 72 h, biofilm formation of 11 selected isolates was quantified under model conditions by a crystal violet staining assay with 96-well plates with different carbon sources (lactose, glucose, maltose, sucrose, and sodium acetate) and NaCl levels and under variable temperature and pH conditions. Biofilm formation was more pronounced at lactose concentrations between 0.25 and 3% compared with 5% lactose, which lead to thinner layers. C. sakazakii isolate C7, isolated from infant milk powder, was the strongest biofilm producer at 10 mM Mg2+ and 5 mM Mn2+, 0.5% sodium acetate, at pH levels between 7 and 9 at 37°C for 24 h. C. sakazakii strain C6 isolated from a plant air filter was identified as a moderate biofilm former and C. sakazakii strain DSM 4485, a clinical isolate, as a weak biofilm former. Based on PCR detection, genes bcsA, bcsB, and bcsG encoding for cellulose could be identified as markers for biofilm formation. Isolates carrying bcsA and bcsB showed significantly stronger biofilm formation than isolates without these genes (P < 0.05), in strong correlation with the results obtained in the crystal violet assay. Further investigations using confocal laser scanning microscopy revealed that extracellular polymeric substances and glycocalyx secretions were the dominating components of the biofilms and that the viable fraction of bacteria in the biofilm decreased over time.},
}
@article {pmid30702383,
year = {2019},
author = {Fernandez-Moure, JS and Mydlowska, A and Shin, C and Vella, M and Kaplan, LJ},
title = {Nanometric Considerations in Biofilm Formation.},
journal = {Surgical infections},
volume = {20},
number = {3},
pages = {167-173},
doi = {10.1089/sur.2018.237},
pmid = {30702383},
issn = {1557-8674},
abstract = {Prosthetic contamination and biofilm formation continue to plague implanted materials. With increasing resistance to traditional antibiotic regimens, alternative approaches to preventing bacterial adhesion and biofilm formation have focused on the physiochemical properties of the prosthetics. Roughness, topography, hydrophobicity, porosity, charge, stiffness, and surface area all influence the processes of adhesion and colonization leading to biofilm formation. In this review, we discuss the physiochemical properties of solid and porous prosthetic materials that influence biofilm formation at the nanometric scale.},
}
@article {pmid30700643,
year = {2019},
author = {Kokubu, E and Kinoshita, E and Ishihara, K},
title = {Inhibitory Effects of Lingonberry Extract on Oral Streptococcal Biofilm Formation and Bioactivity.},
journal = {The Bulletin of Tokyo Dental College},
volume = {60},
number = {1},
pages = {1-9},
doi = {10.2209/tdcpublication.2018-0007},
pmid = {30700643},
issn = {0040-8891},
abstract = {Phenolic compounds in fruits such as cranberries have been shown to promote a number of biological activities. The purpose of this study was to investigate the effects of polyphenolic compound-containing lingonberry extract on oral streptococci and compare them with the known anti-cariogenic activity of cranberries. Water-soluble and polyphenol-rich fractions (Fractions I and II, respectively) were isolated from cranberries and lingonberries. The effects of those fractions on the biofilm formation ability and bioactivity of Streptococcus mutans MT8148R, Streptococcus sobrinus 6715, and Streptococcus sanguinis ATCC 10556 were then evaluated. Cranberry or lingonberry Fraction II (at 0.5-1 mg/ml) significantly reduced biofilm formation by S. mutans, S. sobrinus, and S. sanguinis. In contrast, cranberry or lingonberry Fraction I (at 0.5-2 mg/ml) increased biofilm formation by S. mutans and S. sobrinus, but not by S. sanguinis. Fractions I and II (at 1-2 mg/ml) also reduced the bioactivity of S. mutans, while Fraction II (at 0.5 mg/ml) enhanced the bioactivity of all tested strains. The results revealed that lingonberries contained a larger amount of polyphenol than cranberries and that they showed almost the same level of activity against the biofilm formation ability and bioactivity of oral streptococci. This indicates that polyphenol-rich lingonberry fraction offers a promising natural food derivative for prevention of dental caries.},
}
@article {pmid30698495,
year = {2019},
author = {Woźniak-Biel, A and Bugla-Płoskońska, G and Burdzy, J and Korzekwa, K and Ploch, S and Wieliczko, A},
title = {Antimicrobial Resistance and Biofilm Formation in Enterococcus spp. Isolated from Humans and Turkeys in Poland.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {25},
number = {2},
pages = {277-286},
doi = {10.1089/mdr.2018.0221},
pmid = {30698495},
issn = {1931-8448},
abstract = {Enterococci are a natural component of the intestinal flora of many organisms, including humans and birds. As opportunistic pathogens, they can cause fatal infections of the urinary tract and endocarditis in humans, whereas in poultry symptoms are joint disease, sepsis, and falls in the first week of life. The study covered 107 Enterococcus strains-56 isolated from humans and 51 from turkeys. Among the isolates investigated Enterococcus faecalis was detected in 80.36% of human and 80.39% of turkey samples. Enterococcus faecium was identified in 8.93% of human and 17.65% of turkey strains. The highest percentage of the strains was resistant to tetracycline as follows: 48 (85.71%) and 48 (94.12%) of human and turkey strains, respectively. Resistance to erythromycin occurred in 37.50% of the human and in 76.47% of turkey strains, otherwise 27.10% of all strains showed resistance to ciprofloxacin. Our study revealed that 25% of human and 15.69% of turkey strains were resistant to vancomycin. Multidrug resistance showed in 32.14% and 43.14% of human and turkey strains, respectively. The tetracycline resistance gene, tetM, was detected in 82.24% of all strains analyzed, whereas the tetO gene was found in 53.57% of human but only in 7.84% of turkey strains. The vancomycin resistance gene (vanA) was detected in seven Enterococcus strains (six isolated from turkeys and one from humans). The ermB gene (resistance to macrolide) was detected in 55.14% of all isolates (42.86% of human and 68.63% of turkey strains), whereas the ermA gene was detected in 17.65% of turkey but only in 3.57% of human isolates. All the strains had the ability to form biofilms. A stronger biofilm was formed after 24-hour incubation by strains isolated from turkeys, whereas after 48 hours of incubation all examined strains produced strong biofilm.},
}
@article {pmid30698031,
year = {2018},
author = {Ricciardelli, A and Casillo, A and Papa, R and Monti, DM and Imbimbo, P and Vrenna, G and Artini, M and Selan, L and Corsaro, MM and Tutino, ML and Parrilli, E},
title = {Pentadecanal inspired molecules as new anti-biofilm agents against Staphylococcus epidermidis.},
journal = {Biofouling},
volume = {34},
number = {10},
pages = {1110-1120},
doi = {10.1080/08927014.2018.1544246},
pmid = {30698031},
issn = {1029-2454},
abstract = {Staphylococcus epidermidis, a harmless human skin colonizer, is a significant nosocomial pathogen in predisposed hosts because of its capability to form a biofilm on indwelling medical devices. In a recent paper, the purification and identification of the pentadecanal produced by the Antarctic bacterium Pseudoalteromonas haloplanktis TAC125, able to impair S. epidermidis biofilm formation, were reported. Here the authors report on the chemical synthesis of pentadecanal derivatives, their anti-biofilm activity on S. epidermidis, and their action in combination with antibiotics. The results clearly indicate that the pentadecanal derivatives were able to prevent, to a different extent, biofilm formation and that pentadecanoic acid positively modulated the antimicrobial activity of the vancomycin. The cytotoxicity of these new anti-biofilm molecules was tested on two different immortalized eukaryotic cell lines in view of their potential applications.},
}
@article {pmid30698028,
year = {2018},
author = {Jahid, IK and Mizan, MFR and Myoung, J and Ha, SD},
title = {Aeromonas hydrophila biofilm, exoprotease, and quorum sensing responses to co-cultivation with diverse foodborne pathogens and food spoilage bacteria on crab surfaces.},
journal = {Biofouling},
volume = {34},
number = {10},
pages = {1079-1092},
doi = {10.1080/08927014.2018.1519069},
pmid = {30698028},
issn = {1029-2454},
abstract = {The effects of dual species interactions on biofilm formation by Aeromonas hydrophila in the presence of Pseudomonas aeruginosa, Pseudomonas fluorescens, Pectobacterium carotovorum, Salmonella Typhimurium, and Listeria monocytogenes were examined. High-performance liquid chromatography and liquid-chromatography-mass spectrometry were performed to identify N-acyl homoserine lactone (AHL) molecules secreted by monocultures and dual cultures grown in crab broth. Field emission scanning electron microscopy was performed to observe attachment and biofilm formation. P. aeruginosa and P. fluorescens inhibited biofilm formation by A. hydrophila on the crab surface, without affecting their own biofilm-forming abilities. Dual biofilms of S. Typhimurium, L. monocytogenes, or P. carotovorum did not affect A. hydrophila biofilm formation. Exoprotease, AHL, and AI-2 levels were significantly reduced in dual cultures of P. aeruginosa and P. fluorescens with A. hydrophila, supporting the relationship between quorum sensing and biofilm formation. Dual-species biofilms were studied in their natural environment and in the laboratory.},
}
@article {pmid30697382,
year = {2018},
author = {Froughreyhani, M and Salemmilani, A and Mozafari, A and Hosein-Soroush, M},
title = {Effect of electric currents on antibacterial effect of chlorhexidine against Entrococcus faecalis biofilm: An in vitro study.},
journal = {Journal of clinical and experimental dentistry},
volume = {10},
number = {12},
pages = {e1223-e1229},
doi = {10.4317/jced.55369},
pmid = {30697382},
issn = {1989-5488},
abstract = {Background: This in vitro study was mainly aimed to evaluate the effect of high-frequency alternating currents (AC) applied by an electronic apex locator (EAL) on the antibacterial properties of chlorhexidine (CHX) on E. faecalis biofilm.<br><br>Material and Methods: The root canals of 120 extracted human single-rooted teeth were prepared using Gates-Glidden drills and hand K-files. After contaminating the root canals with E. faecalis, they were incubated for 60 days. Then, the teeth were randomly divided into six experimental groups (n=20). Group 1, 2% CHX; group 2, normal saline (NS) with direct current (DC); group 3, normal saline (NS) with high-frequency alternating current (AC); group 4, 2% CHX with DC; group 5, 2% CHX with AC; group 6, control (normal saline). The samples were collected from the root canal walls of 16 teeth in each group and 1:10 serial dilutions were prepared and added to Muller-Hinton agar (MHA) plates and incubated at 37°C for 48 h. The longitudinal sections of the other 4 teeth used to observe under a scanning electron microscope (SEM). A classic colony counting technique was used for counting the vital E. faecalis bacteria in MHA. Two-way ANOVA was used for statistical analysis of the data. The level of significance was set at P<0.05.<br><br>Results: The electric current significantly changed the colony-forming units (CFU) values (P<0.001). According to pair-wise comparisons, the highest CFU difference was observed between the AC group and the group without electric current (P<0.001); furthermore, the difference between the DC group and the group without electric current was not significant (P=0.823).<br><br>Conclusions: The highest bioelectric effect occurred with the use of high-frequency alternating electric current in the form of an apex locator with CHX as a canal irrigant. Key words:Biofilm, Chlorhexidine, Direct current, Electric current, Enterococcus faecalis.},
}
@article {pmid30694560,
year = {2019},
author = {Torabi Delshad, S and Soltanian, S and Sharifiyazdi, H and Bossier, P},
title = {Effect of catecholamine stress hormones (dopamine and norepinephrine) on growth, swimming motility, biofilm formation and virulence factors of Yersinia ruckeri in vitro and an in vivo evaluation in rainbow trout.},
journal = {Journal of fish diseases},
volume = {42},
number = {4},
pages = {477-487},
doi = {10.1111/jfd.12934},
pmid = {30694560},
issn = {1365-2761},
abstract = {In this study, we evaluated the impact of the catecholamines on growth, swimming motility, biofilm formation and some virulence factors activities of pathogenic Yersinia ruckeri. Norepinephrine and dopamine (at 100 µM) significantly increased the growth of Y. ruckeri in culture media containing serum. An increase in swimming motility of the pathogen was found following the exposure to the hormones; however, no effect was seen on caseinase, phospholipase and haemolysin productions. Further, antagonists for the catecholamine receptors were observed to block some of the influences of the catecholamines. Indeed, the effects of catecholamines were inhibited by chlorpromazine (the dopaminergic receptor antagonist) for dopamine, labetalol (α-and β-adrenergic receptor antagonist) and phenoxybenzamine (the α-adrenergic receptor antagonist) for norepinephrine, but propranolol (the β-adrenergic receptor antagonist) showed no effect. Pretreatment of Y. ruckeri with the catecholamines resulted in a significant enhancement of its virulence towards rainbow trout and the antagonists could neutralize the effect of the stress hormones in vivo. In summary, our results show that the catecholamines increase the virulence of Y. ruckeri which is pathogenic to trout through increasing the motility, biofilm formation and growth.},
}
@article {pmid30692967,
year = {2018},
author = {Li, Z and Xiang, Z and Zeng, J and Li, Y and Li, J},
title = {A GntR Family Transcription Factor in Streptococcus mutans Regulates Biofilm Formation and Expression of Multiple Sugar Transporter Genes.},
journal = {Frontiers in microbiology},
volume = {9},
number = {},
pages = {3224},
doi = {10.3389/fmicb.2018.03224},
pmid = {30692967},
issn = {1664-302X},
abstract = {GntR family transcription factors have been implicated in the regulation of carbohydrate transport and metabolism in many bacteria. However, the function of this transcription factor family is poorly studied in Streptococcus mutans, which is a commensal bacterium in the human oral cavity and a well-known cariogenic pathogen. One of the most important virulence traits of S. mutans is its ability to transport and metabolize carbohydrates. In this study, we identified a GntR transcription factor in S. mutans named StsR (Sugar Transporter Systems Regulator). The deletion of the stsR gene in S. mutans caused a decrease in both the formation of biofilm and the production of extracellular polysaccharides (EPS) at early stage. Global gene expression profiling revealed that the expression levels of 188 genes were changed in the stsR mutant, which could be clustered with the sugar PTS and ABC transporters. Furthermore, StsR protein was purified and its conserved DNA binding motif was determined using electrophoretic mobility shift assays (EMSA) and DNase I footprinting assays. Collectively, the results of this research indicate that StsR is an important transcription factor in S. mutans that regulates the expression of sugar transporter genes, production of EPS and formation of biofilm.},
}
@article {pmid30692576,
year = {2019},
author = {Jing, X and Huang, X and Haapasalo, M and Shen, Y and Wang, Q},
title = {Modeling Oral Multispecies Biofilm Recovery After Antibacterial Treatment.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {804},
doi = {10.1038/s41598-018-37170-w},
pmid = {30692576},
issn = {2045-2322},
support = {32623//Canada Foundation for Innovation (Fondation canadienne pour l&amp;apos;innovation)/ ; DMS-1517347//NSF | Directorate for Mathematical &amp; Physical Sciences | Division of Mathematical Sciences (DMS)/ ; 11571032//National Natural Science Foundation of China (National Science Foundation of China)/ ; 91630207//National Natural Science Foundation of China (National Science Foundation of China)/ ; },
abstract = {Recovery of multispecies oral biofilms is investigated following treatment by chlorhexidine gluconate (CHX), iodine-potassium