@article {pmid31935721,
year = {2020},
author = {Wang, J and Peng, X and Yin, W and Peng, Y and Liu, H and He, L},
title = {Eradication of Microorganisms Embedding in Biofilm by a Dose-Dependent Urokinase-Based Catheter Lock Solution in Chronic Hemodialysis Patients.},
journal = {Blood purification},
volume = {},
number = {},
pages = {1-11},
doi = {10.1159/000505566},
pmid = {31935721},
issn = {1421-9735},
abstract = {INTRODUCTION: Catheter-related blood stream infection (CRBSI), the most common complication of central vein catheter (CVC), was closely associated with high morbidity and mortality in hemodialysis (HD) patients. Conjunction with systemic antibiotic, antibiotic lock (ABL) is an important therapeutic option to salvage the catheter. With extra antimicrobial and biofilm removing properties, urokinase plasminogen activator (uPA)-based ABL could have a potential role in the treatment of CRBSI.<br><br>OBJECTIVE: In this study, we aimed to explore effectiveness of uPA-based (ABL) on microorganisms embedded in biofilms in vitro and CVC salvage rate in HD patients with CRBSI.<br><br>METHODS: In vitro, we induced biofilms formation on the surface of HD catheter by mimicking the development of CRBSI. Applying uPA with or without antibiotics on the kinds of microorganism biofilms to explore its antimicrobial and biofilm removing properties. In vivo, 86 HD patients diagnosed as CRBSI were retrospectively enrolled to see effectiveness of uPA-based ABL on catheter salvage rate as compare to heparin-based ABL.<br><br>RESULTS: uPA was effect to Staphylococcus epidermidis biofilms compared to Staphylococcus aureus, Escherichia coli, and Candida albicans. Less biofilm residues made the regrowth of S. epidermidis also limited. The combination of uPA with antibiotic showed better antimicrobial and antibiofilm activity than uPA alone or heparin-based ABL in vitro and in vivo. Among HD patients, uPA-based ABL did not cause any obvious adverse affects, and it was more effective in treating coagulase-negative Staphylococci related CRBSI than other microorganisms.<br><br>CONCLUSIONS: The combination of uPA and a therapeutic plasma concentration of sensitive antibiotic can work together to effectively remove coagulase-negative S. epidermidis embedded in biofilms in vitro. uPA-based ABL is safe and effective therapeutic intervention for HD patients with CRBSI, especially compared to heparin-based ABL.},
}
@article {pmid31934774,
year = {2020},
author = {Barilli, E and Vismarra, A and Frascolla, V and Rega, M and Bacci, C},
title = {Escherichia coli Strains Isolated from Retail Meat Products: Evaluation of Biofilm Formation Ability, Antibiotic Resistance, and Phylogenetic Group Analysis.},
journal = {Journal of food protection},
volume = {},
number = {},
pages = {233-240},
doi = {10.4315/0362-028X.JFP-19-330},
pmid = {31934774},
issn = {1944-9097},
abstract = {Escherichia coli is a ubiquitous organism capable of forming a biofilm. This is an important virulence factor and is critical in certain diseases and in the development of antibiotic resistance, which is increased by biofilm synthesis. In the present study, the potential health risk associated with handling and consumption of foods of animal origin contaminated with E. coli-producing biofilm was evaluated. We analyzed the ability of 182 E. coli strains isolated from pork, poultry, and beef, purchased in three different supermarkets in the area of the &quot;Italian Food Valley&quot; (Parma, northern Italy), to form biofilms. Positive strains were also tested for the presence of 12 biofilm-associated genes. Moreover, the 182 E. coli were characterized for antibiotic resistance, presence of multidrug resistance, extended-spectrum β-lactamase strains, and phylogenetic diversity through PCR. Twenty-five percent of the isolates produced biofilm. The majority showed weak adherence, five were moderate, and three were strong producers. E. coli with a strong adherence capability (three of three) harbored eight biofilm-associated genes, while weak and moderate producers harbored only five (frequencies ranging from 80 to 100%). Multidrug resistance was observed in 20 biofilm-producing E. coli, and 15 of these belonged to phylogenetic group D. Among nonbiofilm producers, the percentage of strains belonging to phylogenetic groups B2 and D was approximately 40%, highlighting a potential health risk for consumers and people handling contaminated products. The present study underlines the importance of monitoring the prevalence and characteristics of E. coli contaminating retail meat in relation to the potential virulence highlighted here.},
}
@article {pmid31934739,
year = {2020},
author = {Li, J and Zhong, W and Zhang, K and Wang, D and Hu, J and Chan-Park, MB},
title = {Biguanide-Derived Polymeric Nanoparticles Kill MRSA Biofilm and Suppress Infection In Vivo.},
journal = {ACS applied materials &amp; interfaces},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsami.9b17747},
pmid = {31934739},
issn = {1944-8252},
abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of drug-resistant infections. Its propensity to develop biofilms makes it especially resistant to conventional antibiotics. We present a novel nanoparticle (NP) system made from biocompatible F -127 surfactant, t annic acid (TA), and biguanide-based p olymetformin (PMET) (termed FTP NPs), which can kill MRSA biofilm bacteria effectively in vitro and in vivo and which has excellent biocompatibility. FTP NPs exhibit biofilm bactericidal activity-ability to kill bacteria both inside and outside biofilm-significantly better than many antimicrobial peptides or polymers. At low concentrations (8-32 μg/mL) in vitro, FTP NPs outperformed PMET with ∼100-fold (∼2 log10) greater reduction of MRSA USA300 biofilm bacterial cell counts, which we attribute to the antifouling property of the hydrophilic poly(ethylene glycol) contributed by F-127. Further, in an in vivo murine excisional wound model, FTP NPs achieved 1.8 log10 reduction of biofilm-associated MRSA USA300 bacteria, which significantly outperformed vancomycin (0.8 log10 reduction). Moreover, in vitro cytotoxicity tests showed that FTP NPs have less toxicity than PMET toward mammalian cells, and in vivo intravenous injection of FTP NPs at 10 mg/kg showed no acute toxicity to mice with negligible body weight loss and no significant perturbation of blood biomarkers. These biguanide-based FTP NPs are a promising approach to therapy of MRSA infections.},
}
@article {pmid31934344,
year = {2020},
author = {Thöming, JG and Tomasch, J and Preusse, M and Koska, M and Grahl, N and Pohl, S and Willger, SD and Kaever, V and Müsken, M and Häussler, S},
title = {Parallel evolutionary paths to produce more than one Pseudomonas aeruginosa biofilm phenotype.},
journal = {NPJ biofilms and microbiomes},
volume = {6},
number = {},
pages = {2},
doi = {10.1038/s41522-019-0113-6},
pmid = {31934344},
issn = {2055-5008},
abstract = {Studying parallel evolution of similar traits in independent within-species lineages provides an opportunity to address evolutionary predictability of molecular changes underlying adaptation. In this study, we monitored biofilm forming capabilities, motility, and virulence phenotypes of a plethora of phylogenetically diverse clinical isolates of the opportunistic pathogen Pseudomonas aeruginosa. We also recorded biofilm-specific and planktonic transcriptional responses. We found that P. aeruginosa isolates could be stratified based on the production of distinct organismal traits. Three major biofilm phenotypes, which shared motility and virulence phenotypes, were produced repeatedly in several isolates, indicating that the phenotypes evolved via parallel or convergent evolution. Of note, while we found a restricted general response to the biofilm environment, the individual groups of biofilm phenotypes reproduced biofilm transcriptional profiles that included the expression of well-known biofilm features, such as surface adhesive structures and extracellular matrix components. Our results provide insights into distinct ways to make a biofilm and indicate that genetic adaptations can modulate multiple pathways for biofilm development that are followed by several independent clinical isolates. Uncovering core regulatory pathways that drive biofilm-associated growth and tolerance towards environmental stressors promises to give clues to host and environmental interactions and could provide useful targets for new clinical interventions.},
}
@article {pmid31933125,
year = {2020},
author = {Le, TN and Lee, CK},
title = {Surface Functionalization of Poly(N-Vinylpyrrolidone) onto Poly(Dimethylsiloxane) for Anti-Biofilm Application.},
journal = {Applied biochemistry and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12010-020-03238-5},
pmid = {31933125},
issn = {1559-0291},
abstract = {Poly(dimethylsiloxane) (PDMS) has been widely used in the field of microfluidics, optical systems, and sensors. However, the hydrophobic nature of PDMS leads to low surface wettability and biofouling problems due to the nonspecific proteins-hydrophobic surface interactions and cell/bacterial adhesion. In this work, the PDMS surface was first introduced with amino groups (PDMS-NH2) via KOH-catalyzed reaction with 3-aminopropyltriethoxysilane (APTES). The PDMS-NH2 was then grafted with poly(N-vinylpyrrolidone) (PVP) based on the self-adhesion reaction between the amino surface and catechol-functionalized PVP (CA-PLL-PVP). CA-PLL-PVP as a comb-polymer was synthesized by conjugating PVP-COOH along with caffeic acid to the ε-polylysine backbone. A significantly enhanced water wettability was observed with contact angles dropped from 116° to 14° after coating with CA-PLL-PVP. The coated surface demonstrated excellent antifouling performance that no appreciable Staphylococcus epidermidis biofilm formation could be observed. This novel facile antifouling coating on PDMS surface may find greater biomedical applications to eliminate the potential adherence problems caused by natural biofouling.},
}
@article {pmid31932378,
year = {2020},
author = {Jin, Y and Guo, Y and Zhan, Q and Shang, Y and Qu, D and Yu, F},
title = {Sub-Inhibitory Concentrations of Mupirocin Stimulate Staphylococcus aureus Biofilm Formation by Up-regulating cidA.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.01912-19},
pmid = {31932378},
issn = {1098-6596},
abstract = {Previous studies have shown that the administration of antibiotics at sub-inhibitory concentrations stimulates biofilm formation by the majority of MRSA strains. Here, we investigated the effect of sub-inhibitory mupirocin concentrations on biofilm formation by the community-associated (CA) mupirocin-sensitive MRSA strain USA300 and highly mupirocin-resistant clinical S. aureus SA01-SA05 isolates. We found that mupirocin increased the ability of MRSA cells to attach to surfaces and form biofilms. Confocal laser scanning microscopy (CLSM) demonstrated that mupirocin treatment promoted thicker biofilm formation, which also correlated with the production of extracellular DNA (eDNA). Furthermore, RT-qPCR results revealed that this effect was largely due to the involvement of holin-/antiholin-like proteins (encoded by the cidA gene), which are responsible for modulating cell death and lysis during biofilm development. We found that cidA expression levels significantly increased 6.05-35.52 fold (P < 0.01) on mupirocin administration. We generated a cidA-deficient mutant of the USA300 S. aureus strain. Exposure of the ΔcidA mutant to mupirocin did not result in thicker biofilm formation compared with that in the parent strain. We therefore hypothesize that the mupirocin-induced stimulation of S. aureus biofilm formation may involve the upregulation of cidA.},
}
@article {pmid31932310,
year = {2020},
author = {Kimbrough, JH and Cribbs, JT and McCarter, LL},
title = {Homologous c-di-GMP-binding Scr transcription factors orchestrate biofilm development in Vibrio parahaemolyticus.},
journal = {Journal of bacteriology},
volume = {},
number = {},
pages = {},
doi = {10.1128/JB.00723-19},
pmid = {31932310},
issn = {1098-5530},
abstract = {The marine bacterium and human pathogen Vibrio parahaemolyticus rapidly colonizes surfaces by using swarming motility and forming robust biofilms. Entering either colonization program, swarming motility or sessility, involves differential regulation of many genes resulting in a dramatic shift in physiology and behavior. V. parahaemolyticus has evolved complex regulation to control these two processes that have opposing outcomes. One mechanism relies on the balance of the second messenger c-di-GMP: high c-di-GMP favors biofilm formation. V. parahaemolyticus possesses four homologous regulators, the Scr transcription factors, that belong in a Vibrio-specific family of W[F/L/M][T/S]R-motif transcriptional regulators, some members of which have been demonstrated to bind c-di-GMP. In this work, we explore the role of these Scr regulators in biofilm development. We show each protein binds c-di-GMP; this binding requires a critical R in the binding motif; and the biofilm-relevant activities of CpsQ, CpsS, and ScrO, but not ScrP are dependent upon second messenger binding. ScrO and CpsQ are the primary drivers of biofilm formation: biofilms are eliminated when both of these regulators are absent. ScrO is most important for capsule expression. CpsQ is most important for RTX-matrix protein expression, although it contributes to capsule expression when c-di-GMP is high. Both regulators contribute to O-antigen ligase expression. ScrP works oppositely in a minor role to repress the ligase gene. CpsS plays a regulatory checkpointing role by negatively modulating expression of these biofilm-pertinent genes under fluctuating c-di-GMP conditions. Our work further elucidates the multifactorial network that contributes to biofilm development in V. parahaemolyticusImportanceVibrio parahaemolyticus can inhabit open ocean, chitinous shells, and the human gut. Such varied habitats and the transitions between them require adaptable regulatory networks controlling energetically expensive behaviors including swarming motility and biofilm formation, which are promoted by low and high concentrations of the signaling molecule c-di-GMP, respectively. Here, we describe four homologous c-di-GMP-binding Scr transcription factors in V. parahaemolyticus Members of this family of regulators are present in many vibrios, yet their number and the nature of their activities differ across species. Our work highlights the distinctive roles that these transcription factors play in dynamically controlling biofilm formation and architecture in V. parahaemolyticus and serves as a powerful example of regulatory network evolution and diversification.},
}
@article {pmid31930157,
year = {2015},
author = {Brown, L and Kessler, A and Casadevall, A},
title = {Vesicle Isolation from Bacillus subtilis Biofilm.},
journal = {Bio-protocol},
volume = {5},
number = {5},
pages = {},
doi = {10.21769/BioProtoc.1409},
pmid = {31930157},
issn = {2331-8325},
abstract = {Bacterial biofilms are associated clinically with many bacterial infections including those caused by bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus. In recent years, extracellular vesicles produced by bacteria have been isolated from biofilm communities. Vesicles have been described in depth and can encapsulate various virulence factors including toxins and immunomodulatory compounds. Vesicles may be important for virulence and survival by serving as a vehicle for the secretion and concentrated delivery of these molecules. Studying extracellular vesicles is an important step towards understanding biofilm formation, structure, and disruption with the ultimate goal of preventing or treating hospital infections caused by bacterial pathogens residing in biofilms. Here we describe the protocol for isolating vesicles from biofilm produced by Bacillus subtilis.},
}
@article {pmid31931228,
year = {2019},
author = {Paniagua, AT and Paranjape, K and Hu, M and Bédard, E and Faucher, SP},
title = {Impact of temperature on Legionella pneumophila, its protozoan host cells, and the microbial diversity of the biofilm community of a pilot cooling tower.},
journal = {The Science of the total environment},
volume = {712},
number = {},
pages = {136131},
doi = {10.1016/j.scitotenv.2019.136131},
pmid = {31931228},
issn = {1879-1026},
abstract = {Legionella pneumophila is a waterborne bacterium known for causing Legionnaires' Disease, a severe pneumonia. Cooling towers are a major source of outbreaks, since they provide ideal conditions for L. pneumophila growth and produce aerosols. In such systems, L. pneumophila typically grow inside protozoan hosts. Several abiotic factors such as water temperature, pipe material and disinfection regime affect the colonization of cooling towers by L. pneumophila. The local physical and biological factors promoting the growth of L. pneumophila in water systems and its spatial distribution are not well understood. Therefore, we built a lab-scale cooling tower to study the dynamics of L. pneumophila colonization in relationship to the resident microbiota and spatial distribution. The pilot was filled with water from an operating cooling tower harboring low levels of L. pneumophila. It was seeded with Vermamoeba vermiformis, a natural host of L. pneumophila, and then inoculated with L. pneumophila. After 92 days of operation, the pilot was disassembled, the water was collected, and biofilm was extracted from the pipes. The microbiome was studied using 16S rRNA and 18S rRNA genes amplicon sequencing. The communities of the water and of the biofilm were highly dissimilar. The relative abundance of Legionella in water samples reached up to 11% whereas abundance in the biofilm was extremely low (≤0.5%). In contrast, the host cells were mainly present in the biofilm. This suggests that L. pneumophila grows in host cells associated with biofilm and is then released back into the water following host cell lysis. In addition, water temperature shaped the bacterial and eukaryotic community of the biofilm, indicating that different parts of the systems may have different effects on Legionella growth.},
}
@article {pmid31931147,
year = {2020},
author = {Britt, NS and Hazlett, DS and Horvat, RT and Liesman, RM and Steed, ME},
title = {Activity of Pulmonary Vancomycin Exposures versus Planktonic and Biofilm Methicillin-Resistant Staphylococcus aureus Isolated from Cystic Fibrosis Sputum.},
journal = {International journal of antimicrobial agents},
volume = {},
number = {},
pages = {105898},
doi = {10.1016/j.ijantimicag.2020.105898},
pmid = {31931147},
issn = {1872-7913},
abstract = {Vancomycin is commonly used to treat methicillin-resistant Staphylococcus aureus (MRSA) infection in patients with cystic fibrosis (CF) lung disease; however, there are limited data to support the in vitro activity of this agent against MRSA isolated from CF sputum. The primary objective of this study was to evaluate the activity of vancomycin at pulmonary concentrations (intravenous and inhaled) against 4 clinical MRSA CF sputum isolates in planktonic and biofilm time-kill (TK) experiments. Vancomycin minimum inhibitory concentrations (MICs) were determined for these isolates at standard inoculum (SI; ∼106 colony-forming units [CFU]/mL) and high inoculum (HI; ∼108 CFU/mL), and in biofilms cultivated using physiologic media recapitulating the microenvironment of the CF lung. Vancomycin concentrations of 10, 25, 100, and 275 µg/mL were evaluated in TK experiments against planktonic MRSA at varying inocula and versus biofilm MRSA. Vancomycin MICs increased from 0.5 µg/mL at SI to 8-16 µg/mL when tested at HI. Vancomycin MICs were further increased to 16-32 µg/mL in biofilm studies. In TK experiments, vancomycin displayed bactericidal activity (≥ 3 log10 killing at 24 h) against 1/4 and 0/4 planktonic MRSA isolates at SI and HI, respectively. Against MRSA biofilms, vancomycin was bactericidal against 0/4 isolates. Based on these findings, vancomycin monotherapy appears unlikely to eradicate MRSA from the respiratory tract of patients with CF, even at high concentrations similar to those observed with inhaled therapy. Novel vancomycin formulations with enhanced biofilm penetration or combination therapy with other potentially synergistic agents should be explored.},
}
@article {pmid31931057,
year = {2020},
author = {Thinakaran, S and Loordhuswamy, A and Rangaswamy, GV},
title = {Electrophoretic deposition of chitosan/nano silver embedded micro sphere on centrifugal spun fibrous matrices - A facile biofilm resistant biocompatible material.},
journal = {International journal of biological macromolecules},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijbiomac.2020.01.086},
pmid = {31931057},
issn = {1879-0003},
abstract = {Micro fibrous polycaprolactone (PCL) mat generally used for biomedical application was produced by facile centrifugal spinning system (C-Spin). The produced mat exhibited good structural integrity and good flexibility. The developed mat was used as substrate for electrophoretic deposition (EPD) of chitosan and polyethylene glycol (PEG) along with silver nano particles (AgNPs). During the EPD process, polymeric micro spheres embedded with silver nano particles were formed and deposited on the C-Spun substrates and the size of AgNPs were found to be around 15 nm. Surface topography of all coated samples were analyzed and found that the deposition was neat and uniform. Swelling behavior of the coated substrates were studied and found that CS/HMP/AgNPs coated substrates showed 274% swelling compared to their own dry weight. Release profile of silver nanoparticles confirmed that initial burst release followed by sustained release for CS/HMP/AgNPs coated substrates and this might be attributed to the hydrophilicity and high swellability of HMP. All AgNPs coated samples were completely prevent the bacterial biofilm formation and CS/HMP/AgNPs showed better reduction in bacterial growth on matured biofilm model. Cell proliferation studies confirmed that CS/HMP/AgNPs is biocompatible and can be used as a wound dressing material.},
}
@article {pmid31930132,
year = {2019},
author = {Lucio-Sauceda, DG and Urrutia-Baca, VH and Gomez-Flores, R and De La Garza-Ramos, MA and Tamez-Guerra, P and Orozco-Flores, A},
title = {Antimicrobial and Anti-Biofilm Effect of an Electrolyzed Superoxidized Solution at Neutral-pH against Helicobacter pylori.},
journal = {BioMed research international},
volume = {2019},
number = {},
pages = {6154867},
doi = {10.1155/2019/6154867},
pmid = {31930132},
issn = {2314-6141},
abstract = {The presence of Helicobacter pylori in the oral cavity has been associated to the failure of antimicrobial therapy in patients with gastrointestinal infection and the development of oral diseases. However, it has been reported that the maintenance of good oral hygiene can improve the therapeutic success rates, where the use of mouthwashes with anti-Helicobacter activity would help to achieve it. The aim was to evaluate the antimicrobial activity of OxOral® mouthwash against H. pylori and its effect on biofilm formation. The minimum inhibitory concentration (MIC) of OxOral® (pH = 6.4-7.5, ORP = 650-900 mV) against H. pylori was calculated testing serial dilutions 0.117-15 ppm against 1 × 108 CFU/mL of H. pylori (ATCC® 700824™) by broth microdilution method using 96-well plates. The H. pylori biofilm formation was determined by the optical density measurement at 600 nm from coverslips stained with 0.1% crystal violet. The gene expression of ureA, luxS, flaA, omp18, and lpxD were analyzed by RT-qPCR. OxOral® cytotoxicity was evaluated in a human gingival fibroblast cell line by MTT assay. MIC was of 3.75 ppm, with 99.7 ± 7.7% bacterial growth inhibition. In the negative control, the biofilm formation was observed, whereas when bacteria were treated with OxOral® at 0.234, 0.469, and 0.938 ppm, an inhibition of 35.5 ± 0.9%, 89.1 ± 1.2%, and 99.9 ± 5.5% were obtained, respectively. The gene expression analysis showed that flaA, omp18, and lpxD genes were down-regulated with OxOral® compared with control (p < 0.05). Low cytotoxicity of 16.5 ± 7.6% was observed at the highest dose (15 ppm); no significant differences were observed from 15 to 0.469 ppm compared to the control of untreated cells (p > 0.05). Our results reveal an important anti-Helicobacter activity of OxOral® and open the possibility of its therapeutic use new studies, which would increase the success rate of conventional therapies against H. pylori.},
}
@article {pmid31929848,
year = {2019},
author = {Avila-Novoa, MG and Solís-Velázquez, OA and Rangel-López, DE and González-Gómez, JP and Guerrero-Medina, PJ and Gutiérrez-Lomelí, M},
title = {Biofilm Formation and Detection of Fluoroquinolone- and Carbapenem-Resistant Genes in Multidrug-Resistant Acinetobacter baumannii.},
journal = {The Canadian journal of infectious diseases &amp; medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale},
volume = {2019},
number = {},
pages = {3454907},
doi = {10.1155/2019/3454907},
pmid = {31929848},
issn = {1712-9532},
abstract = {Acinetobacter baumannii is an important opportunistic pathogen that shows resistance to cephalosporins, penicillins, carbapenems, fluoroquinolones, and aminoglycosides, the multiresistance being associated with its ability to form biofilms in clinical environments. The aim of this study was to determine biofilm formation and its potential association with genes involved in antibiotic resistance mechanisms of A. baumannii isolates of different clinical specimens. We demonstrated 100% of the A. baumannii isolates examined to be multidrug resistant (MDR), presenting a 73.3% susceptibility to cefepime and a 53.3% susceptibility to ciprofloxacin. All A. baumannii isolates were positive for blaOXA-51, 33.3% being positive for blaOXA-23 and ISAba1, and 73.3% being positive for gyrA. We found 86.6% of A. baumannii strains to be low-grade biofilm formers and 13.3% to be biofilm negative; culturing on Congo red agar (CRA) plates revealed that 73.3% of the A. baumannii isolates to be biofilm producers, while 26.6% were not. These properties, combined with the role of A. baumannii as a nosocomial pathogen, increase the probability of A. baumannii causing nosocomial infections and outbreaks as a complication during therapeutic treatments and emphasize the need to control A. baumannii biofilms in hospital environments.},
}
@article {pmid31929046,
year = {2020},
author = {Obata, O and Salar-Garcia, MJ and Greenman, J and Kurt, H and Chandran, K and Ieropoulos, I},
title = {Development of efficient electroactive biofilm in urine-fed microbial fuel cell cascades for bioelectricity generation.},
journal = {Journal of environmental management},
volume = {258},
number = {},
pages = {109992},
doi = {10.1016/j.jenvman.2019.109992},
pmid = {31929046},
issn = {1095-8630},
abstract = {The Microbial fuel cell (MFC) technology harnesses the potential of some naturally occurring bacteria for electricity generation. Digested sludge is commonly used as the inoculum to initiate the process. There are, however, health hazards and practical issues associated with the use of digested sludge depending on its origin as well as the location for system deployment. This work reports the development of an efficient electroactive bacterial community within ceramic-based MFCs fed with human urine in the absence of sludge inoculum. The results show the development of a uniform bacterial community with power output levels equal to or higher than those generated from MFCs inoculated with sludge. In this case, the power generation begins within 2 days of the experimental set-up, compared to about 5 days in some sludge-inoculated MFCs, thus significantly reducing the start-up time. The metagenomics analysis of the successfully formed electroactive biofilm (EAB) shows significant shifts between the microbial ecology of the feeding material (fresh urine) and the developed anodic biofilm. A total of 21 bacteria genera were detected in the urine feedstock whilst up to 35 different genera were recorded in the developed biofilm. Members of Pseudomonas (18%) and Anaerolineaceae (17%) dominate the bacterial community of the fresh urine feed while members of Burkholderiaceae (up to 50%) and Tissierella (up to 29%) dominate the anodic EAB. These results highlight a significant shift in the bacterial community of the feedstock towards a selection and adaptation required for the various electrochemical reactions essential for survival through power generation.},
}
@article {pmid31928337,
year = {2020},
author = {Trojanowicz, K and Plaza, E},
title = {Combining numerical simulation with response surface modelling for optimization of reject water partial nitritation/anammox in moving bed biofilm reactor.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-31},
doi = {10.1080/09593330.2020.1714747},
pmid = {31928337},
issn = {1479-487X},
abstract = {Optimization of a single-stage, partial nitritation/anammox (PN/A) process for a reject water treatment in a continuous-flow, moving bed biofilm reactor (MBBR) was presented. Response surface methodology (RSM) was combined with simulation experiments conducted with the validated mathematical model of PN/A in MBBR. The total inorganic nitrogen (TIN) removal efficiency was the response parameter. Eight independent variables were taken into examination: reject water flow rate (Q), inflow concentrations of the total ammonium nitrogen (TAN), chemical oxygen demand (COD), alkalinity (ALK), pH, temperature (T), dissolved oxygen concentration in the bulk liquid (DO) and aeration time within 60 minutes intermittent aeration cycle (AERON). Eleven interactions between independent variables were found as significant (p < 0.05). The interaction of AERON*DO had the highest impact on PN/A process. Optimal values of the controlled variables were found for two cases of MBBR operation. Verification of the optimization was done by simulation and comparison with the data from the empirical experiments. Under conditions of the fixed hydraulic retention time of about 38 hours, volumetric nitrogen loading rate of 0.48 gN/m3d, T of 22.5°C, TAN of 750 gN/m3 and optimized values of DO = 3.0 gO2/m3, AERON = 0.54 hour, pH = 7.5, ALK = 80 molHCO3/m3, COD = 775 gO2/m3, the predicted TINrem was 78% which is consistent with PN/A performance observed in the technical-scale MBBR systems.},
}
@article {pmid31928216,
year = {2020},
author = {Liu, C and Zhu, L and Chen, L},
title = {Mechanism of biofilm formation on a hydrophobic polytetrafluoroethylene membrane during the purification of surface water using direct contact membrane distillation (DCMD), with especial interest in the feed properties.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-18},
doi = {10.1080/08927014.2019.1710136},
pmid = {31928216},
issn = {1029-2454},
abstract = {The impact of feed water quality on biofilm formation during membrane distillation (MD) was investigated in this study, particularly emphasizing the interrelationship between organics, salts, and microbes. Two types of typical natural surface waters in Nanjing, China, were chosen as feed solutions for long-term MD operation, including the Qinhuai River and Xuanwu Lake. The biofilms that developed under different feed water qualities exhibited distinct Foulant compositions and structures, causing different flux decline trends for the MD system. Accordingly, two typical patterns of biofilm formation were suggested for the MD operation of the two different kinds of surface waters in this study. Organics from a primal feed solution and dead bacteria were the key to the establishment of a biofilm on the membrane, and this needs to be effectively removed from the MD system through pre-treatment and process control strategies. Finally, a feasible strategy for MD biofouling control was suggested.},
}
@article {pmid31927950,
year = {2020},
author = {Dong, H and Zhang, W and Wang, Y and Liu, D and Wang, P},
title = {Biofilm polysaccharide display platform: A natural, renewable, and biocompatible material for improved lipase performance.},
journal = {Journal of agricultural and food chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.jafc.9b07209},
pmid = {31927950},
issn = {1520-5118},
abstract = {Most of microorganisms can form biofilms, which makes biofilms become an abundant bioresource to be exploited. Due to the application limitations of current immobilization methods onto biofilms, we developed an immobilization method called the Biofilm Polysaccharides Display (BPD) strategy while maintaining the native biofilm structure and catalytic microenvironment of C. acetobutylicum B3. Lipase Lip181 showed significant improvements in stability after chemical immobilization. For example, immobilized Lip181 retained 74.23% of its original activity after incubation for 14 days while free Lip181 was totally deactivated. In addition, immobilized Lip181 maintained high residual activity (pH 5.0pH 11.0), which showed improved resistance to pH changes. Notably, this method did not decrease but slightly increased the relative activity of Lip181 from 6.39 to 6.78 U/mg. Immobilized Lip181 was used to prepare cinnamyl acetate, and it showed a maximum yield of 85.09%. Overall, this biofilm immobilization method may promote the development of biocatalysis and biofilm materials.},
}
@article {pmid31927762,
year = {2020},
author = {Paluch, E and Rewak-Soroczyńska, J and Jędrusik, I and Mazurkiewicz, E and Jermakow, K},
title = {Prevention of biofilm formation by quorum quenching.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-020-10349-w},
pmid = {31927762},
issn = {1432-0614},
abstract = {Quorum sensing (QS) is a mechanism that enables microbial communication. It is based on the constant secretion of signaling molecules to the environment. The main role of QS is the regulation of vital processes in the cell such as virulence factor production or biofilm formation. Due to still growing bacterial resistance to antibiotics that have been overused, it is necessary to search for alternative antimicrobial therapies. One of them is quorum quenching (QQ) that disrupts microbial communication. QQ-driving molecules can decrease or even completely inhibit the production of virulence factors (including biofilm formation). There are few QQ strategies that comprise the use of the structural analogues of QS receptor autoinductors (AI). They may be found in nature or be designed and synthesized via chemical engineering. Many of the characterized QQ molecules are enzymes with the ability to degrade signaling molecules. They can also impede cellular signaling cascades. There are different techniques used for testing QS/QQ, including chromatography-mass spectroscopy, bioluminescence, chemiluminescence, fluorescence, electrochemistry, and colorimetry. They all enable qualitative and quantitative measurements of QS/QQ molecules. This article gathers the information about the mechanisms of QS and QQ, and their effect on microbial biofilm formation. Basic methods used to study QS/QQ, as well as the medical and biotechnological applications of QQ, are also described. Basis research methods are also described as well as medical and biotechnological application.},
}
@article {pmid31927753,
year = {2020},
author = {Akoğlu, A},
title = {The effect of some environmental conditions on planktonic growth and biofilm formation by some lactic acid bacteria isolated from a local cheese in Turkey.},
journal = {Biotechnology letters},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10529-020-02794-4},
pmid = {31927753},
issn = {1573-6776},
abstract = {OBJECTIVE: The purpose of this study was to determine the effect of some environmental conditions (different temperature degrees and pH values, different salt, glucose and lactose concentrations) on the planktonic growth and biofilm formation ability of the lactic acid bacteria (LAB) isolated from a local cheese in Turkey.<br><br>RESULTS: It was determined that Enterococcus lactis EC61 and Enterococcus faecalis EC41 are the most resistant bacteria to the changing environmental conditions and they can stably maintain their planktonic growth in the pH values of 6.5, 7.0, 7.5, and 8.0; in the salt concentrations of 4% and 6.5%; in the glucose concentration of 0.5%; and in the lactose concentrations of 0.5%, 1.5%, and 2.5%. It was found that all strains had the biofilm formation ability and especially the biofilm formation of Enterococcus lactis EC61 and Enterococcus faecalis EC41 strains significantly increased in the acidic pH values and in the increasing glucose and lactose concentrations, and significantly decreased in the increasing salt concentration.<br><br>CONCLUSIONS: When considered in terms of LAB potential as a starter culture, specifying the effect of some environmental conditions on the planktonic growth and biofilm formation ability is important for the food industry. As a conclusion, it was determined that lactic acid bacteria, which were previously determined to have some starter culture characteristics, had additional properties on the way to being an starter culture.},
}
@article {pmid31927517,
year = {2020},
author = {Hasan, ME and Shahriar, A and Shams, F and Nath, AK and Emran, TB},
title = {Correlation between biofilm formation and antimicrobial susceptibility pattern toward extended spectrum β-lactamase (ESBL)- and non-ESBL-producing uropathogenic bacteria.},
journal = {Journal of basic and clinical physiology and pharmacology},
volume = {},
number = {},
pages = {},
doi = {10.1515/jbcpp-2019-0296},
pmid = {31927517},
issn = {2191-0286},
abstract = {Background Urinary tract infections (UTIs) are the most common bacterial infection encountered worldwide and are associated with significant morbidity and mortality. Methods The present study was undertaken to investigate the biofilm-forming ability, antibiotic susceptibility patterns and extended spectrum β-lactamase (ESBL) production of seven uropathogenic isolates comprising both Escherichia coli and Klebsiella pneumoniae. The morphological, cultural and biochemical tests for the identification of the isolates, antibiotic susceptibility test, detection of ESBL production, biofilm formation on 96-well microtiter plate and Congo red agar (CRA) media are performed. Results The antimicrobial susceptibility profiles obtained in this study showed that the most active drugs gentamicin, amikacin and imipenem (100% sensitivity) were followed by amoxicillin-clavulanic acid (85% sensitivity), co-trimoxazole, ciprofloxacin (57% sensitivity) ceftazidime and kanamycin (50% sensitivity). All the isolates showed resistance to amoxicillin followed by ceftriaxone and cefotaxime (71% resistance), and the scenario gets more complicated because of the production of ESBL by five isolates (three E. coli isolates and two K. pneumoniae). The strains were also able to form biofilm as tested on CRA medium and by microtiter plate assay. The correlation between ESBL, non-ESBL and biofilm-producing E. coli and K. pneumonia was determined along with the multiple drug resistance patterns of E. coli and K. pneumonia. Conclusions The findings of the study indicate that the emergence and rapid spread of such multidrug-resistant pathogens are of great concern. Early detection of ESBL-producing pathogen is of paramount clinical importance; therefore, strict infection control practices as well as therapeutic guidance for confirmed infection can be rapidly initiated.},
}
@article {pmid31925253,
year = {2019},
author = {Suleiman, M and Schröder, C and Kuhn, M and Simon, A and Stahl, A and Frerichs, H and Antranikian, G},
title = {Microbial biofilm formation and degradation of octocrylene, a UV absorber found in sunscreen.},
journal = {Communications biology},
volume = {2},
number = {1},
pages = {430},
doi = {10.1038/s42003-019-0679-9},
pmid = {31925253},
issn = {2399-3642},
abstract = {Octocrylene is a widely used synthetic UV absorber of sunscreens and found in several environments. Ecological consequences of the accumulation of UV filters are widely discussed. This is the first report revealing the microbial potential to transform octocrylene. A microbial community comprising four bacterial species was enriched from a landfill site using octocrylene as carbon source. From these microorganisms Mycobacterium agri and Gordonia cholesterolivorans were identified as most potent applying a new &quot;reverse discovery&quot; approach. This relies on the possibility that efficient strains that are already isolated and deposited can be identified through enrichment cultures. These strains formed massive biofilms on the octocrylene droplets. GC-MS analysis after cultivation for 10 days with M. agri revealed a decrease in octocrylene concentration of 19.1%. LC-MS/MS analysis was utilized in the detection and quantification of transformation products of octocrylene. M. agri thus represents an ideal candidate for bioremediation studies with octocrylene and related compounds.},
}
@article {pmid31924268,
year = {2020},
author = {Kamali, E and Jamali, A and Ardebili, A and Ezadi, F and Mohebbi, A},
title = {Evaluation of antimicrobial resistance, biofilm forming potential, and the presence of biofilm-related genes among clinical isolates of Pseudomonas aeruginosa.},
journal = {BMC research notes},
volume = {13},
number = {1},
pages = {27},
doi = {10.1186/s13104-020-4890-z},
pmid = {31924268},
issn = {1756-0500},
support = {110212//Golestan University of Medical Sciences/ ; },
abstract = {OBJECTIVES: Pseudomonas aeruginosa is known as a leading cause of nosocomial infections worldwide. Antimicrobial resistance and biofilm production, as two main virulence factors of P. aeruginosa, are responsible for the persistence of prolonged infections. In this study, antimicrobial susceptibility pattern and phenotypic and genotypic characteristics of biofilm of P. aeruginosa were investigated.<br><br>RESULTS: A total of 80 clinical P. aeruginosa isolates were obtained. Isolates showed resistance to all antibiotics with a rate from 12.5% (n = 10) against amikacin and piperacillin/tazobactam to 23.75% (n = 19) to levofloxacin. Multidrug-resistant P. aeruginosa accounted for 20% (n = 16). 83.75% (n = 67) of isolates showed biofilm phenotype. All three biofilm-related genes were found simultaneously in 87.5% (n = 70) of P. aeruginosa and 13.5% (n = 10) of the isolates had none of the genes tested. From the results of the present study, combination therapy including an anti-pseudomonal beta-lactam (piperacillin/tazobactam or ceftazidime) and an aminoglycoside or carbapenems (imipenem, meropenem) with fluoroquinolones in conjunction with an aminoglycoside can be used against Pseudomonas infections. However, reasonable antimicrobial use and high standards of infection prevention and control are essential to prevent further development of antimicrobial resistance. Combination strategies based on the proper anti-pseudomonal antibiotics along with anti-biofilm agents can also be selected to eradicate biofilm-associated infections.},
}
@article {pmid31923978,
year = {2020},
author = {Tan, Y and Ma, S and Leonhard, M and Moser, D and Ludwig, R and Schneider-Stickler, B},
title = {Co-immobilization of cellobiose dehydrogenase and deoxyribonuclease I on chitosan nanoparticles against fungal/bacterial polymicrobial biofilms targeting both biofilm matrix and microorganisms.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {108},
number = {},
pages = {110499},
doi = {10.1016/j.msec.2019.110499},
pmid = {31923978},
issn = {1873-0191},
abstract = {Polymicrobial biofilm related infections have been a major threat in health care. In this study, the co-immobilization of cellobiose dehydrogenase (CDH) and deoxyribonuclease I (DNase) on positively charged chitosan nanoparticles (CSNPs) resulted in a bi-functional nanoparticle (CSNP-DNase-CDH) targeting both biofilm matrix and microorganisms. The in-vitro antibiofilm activities of CSNPs against monomicrobial and polymicrobial biofilms of Candida albicans and Staphylococcus aureus were evaluated. The results showed that CSNPs were able to penetrate across the matrix of biofilms and interfere with embedded microbial cells. CSNP-DNase-CDH exhibited a higher activity than CSNPs loaded with only DNase or CDH for inhibiting monomicrobial and polymicrobial biofilm formation as well as for disrupting pre-formed biofilms. Furthermore, CSNP-DNase-CDH could disrupt the biofilm formation through degradation of eDNA, reduce biofilm thickness, and kill microbial cells on silicone. The bi-functional CSNP is applicable for the protection of medical devices from polymicrobial biofilms or the treatment of device associated infections.},
}
@article {pmid31923962,
year = {2020},
author = {Mahamuni-Badiger, PP and Patil, PM and Badiger, MV and Patel, PR and Thorat-Gadgil, BS and Pandit, A and Bohara, RA},
title = {Biofilm formation to inhibition: Role of zinc oxide-based nanoparticles.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {108},
number = {},
pages = {110319},
doi = {10.1016/j.msec.2019.110319},
pmid = {31923962},
issn = {1873-0191},
abstract = {Zinc oxide nanoparticles have received much attention worldwide as they possess unique properties like varied morphology, large surface area to volume ratio, potent antibacterial activity, and biocompatibility. Biofilm contains homogenous or heterogeneous microorganisms that remain enclosed in a matrix of an extracellular polymeric substance on biotic or abiotic surfaces. Bacterial biofilm formed on medical devices such as central venous catheters, urinary catheters, prosthetic joints, cardiovascular implantable devices, dental implants, contact lenses, intrauterine contraceptive devices and breast implants cause persistent infections. Such biofilm-associated infections in medical implants cause serious problems for public health and affect the function of medical implants. So, there is an urgent need for the use of an antimicrobial agent that will inhibit biofilm, including such antibiotic-resistant bacterial strains as bacteria, to develop multiple drug-resistances resulting in failure of the antibiotic's action. The antimicrobial agent used should be ideal in terms of biocompatibility, antimicrobial activity, stability at different environmental conditions, with less sensitivity to the development of resistance towards micro-organisms, safe for in vivo and in vitro use, and remain non-hazardous to the environment, etc. The first objective of the review discusses the insights into the formation of biofilm on a medical device with the current strategies to inhibit. The second purpose is to review the recent progress in ZnO- based nanostructure including composites for antibacterial and anti-biofilm activities. This will offer a new opportunity for the application of Zinc oxide-based material in the prevention of biofilm on the medical devices.},
}
@article {pmid31922722,
year = {2020},
author = {Elbourne, A and Cheeseman, S and Atkin, P and Truong, NP and Syed, N and Zavabeti, A and Mohiuddin, M and Esrafilzadeh, D and Cozzolino, D and McConville, CF and Dickey, MD and Crawford, RJ and Kalantar-Zadeh, K and Chapman, J and Daeneke, T and Truong, VK},
title = {Antibacterial Liquid Metals: Biofilm Treatment via Magnetic Activation.},
journal = {ACS nano},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsnano.9b07861},
pmid = {31922722},
issn = {1936-086X},
abstract = {Antibiotic resistance has made the treatment of biofilm-related infections challenging. As such, the quest for next-generation antimicrobial technologies must focus on targeted therapies to which pathogenic bacteria cannot develop resistance. Stimuli-responsive therapies represent an alternative technological focus due to their capability of delivering targeted treatment. This study provides a proof-of-concept investigation into the use of magneto-responsive gallium-based liquid metal (LM) droplets as antibacterial materials, which can physically damage, disintegrate, and kill pathogens within a mature biofilm. Once exposed to a low-intensity rotating magnetic field, the LM droplets become physically actuated and transform their shape, developing sharp edges. When placed in contact with a bacterial biofilm, the movement of the particles resulting from the magnetic field, coupled with the presence of nanosharp edges, physically ruptures the bacterial cells and the dense biofilm matrix is broken down. The antibacterial efficacy of the magnetically activated LM particles was assessed against both Gram-positive and Gram-negative bacterial biofilms. After 90 min over 99% of both bacterial species became nonviable, and the destruction of the biofilms was observed. These results will impact the design of next-generation, LM-based biofilm treatments.},
}
@article {pmid31922274,
year = {2020},
author = {Gilbertie, JM and Schaer, TP and Schubert, AG and Jacob, ME and Menegatti, S and Ashton Lavoie, R and Schnabel, LV},
title = {Platelet-rich plasma lysate displays anti-biofilm properties and restores antimicrobial activity against synovial fluid biofilms in vitro.},
journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society},
volume = {},
number = {},
pages = {},
doi = {10.1002/jor.24584},
pmid = {31922274},
issn = {1554-527X},
abstract = {Infectious arthritis is difficult to treat in both human and veterinary clinical practice. Recent literature reports Staphylococcus aureus as well as other gram-positive and gram-negative isolates forming free-floating biofilms in both human and equine synovial fluid that are tolerant to traditional antimicrobial therapy. Using an in vitro equine model, we investigated the ability of platelet-rich plasma (PRP) formulations to combat synovial fluid biofilm aggregates. Synovial fluid was infected, and biofilm aggregates allowed to form over a 2 hour period. PRP was collected and processed into different formulations by platelet concentration, leukocyte presence, and activation or lysis. Infected synovial fluid was treated with different PRP formulations with or without aminoglycoside co-treatment. Bacterial load (CFU/mL) was determined by serial dilutions and plate counting at 8 hours post-treatment. All PRP formulations displayed antimicrobial properties; however, formulations containing higher concentrations of platelets without leukocytes had increased antimicrobial activity. Lysis of PRP and pooling of the PRP lysate (PRP-L) from multiple horses as compared to individual horses further increased antimicrobial activity. This activity was lost with removal of the plasma component or inhibition of the proteolytic activity within the plasma. Fractionation of pooled PRP-L identified the bioactive components to be cationic and low molecular weight (< 10 kDa). Overall, PRP-L exhibited synergism with amikacin against aminoglycoside tolerant biofilm aggregates with greater activity against gram-positive bacteria. In conclusion, the use of PRP-L has the potential to augment current antimicrobial treatment regimens which could lead to a decrease in morbidity and mortality associated with infectious arthritis. This article is protected by copyright. All rights reserved.},
}
@article {pmid31922015,
year = {2018},
author = {Vergalito, F and Pietrangelo, L and Petronio Petronio, G and Colitto, F and Alfio Cutuli, M and Magnifico, I and Venditti, N and Guerra, G and Di Marco, R},
title = {Vitamin E for Prevention of Biofilm-caused Healthcare-associated Infections.},
journal = {Open medicine (Warsaw, Poland)},
volume = {15},
number = {},
pages = {14-21},
doi = {10.1515/med-2020-0004},
pmid = {31922015},
issn = {2391-5463},
abstract = {The healthcare-associated infections (HCAIs) occur in patients both in nosocomial environments and in community. More often HCAIs are associated to the use of medical devices and bacterial biofilm development on these equipments. Due to the clinical and economic relevance of this topic, new strategies for the treatment of infections caused by biofilm proliferation are unceasingly searched by scientists. The present study investigated the role of vitamin E to reduce the biofilm formation for a larger panel of human pathogens, including strains of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Acinetobacter baumannii, Pseudomonas aeruginosa and Pseudomonas putida. This potential activity was tested by placing a preparation of vitamin E (α-Tocopheryl acetate) as interface between the bacterial culture and the polystyrene walls of a 96 well plate at different concentrations of glucose, used as a biofilm enhancer. The Staphylococcus genus was further investigated by spreading the vitamin E on a silicone catheter lumen and evaluating its influence on the bacterial colonization. From our results, vitamin E has been able to interfere with bacterial biofilm and prevent in vitro biofilm formation. Furthermore, the ability of Staphylococcus aureus and Staphylococcus epidermidis to colonize the catheter surface decreased as a result of vitamin E application.},
}
@article {pmid31921707,
year = {2019},
author = {Ng, HM and Slakeski, N and Butler, CA and Veith, PD and Chen, YY and Liu, SW and Hoffmann, B and Dashper, SG and Reynolds, EC},
title = {The Role of Treponema denticola Motility in Synergistic Biofilm Formation With Porphyromonas gingivalis.},
journal = {Frontiers in cellular and infection microbiology},
volume = {9},
number = {},
pages = {432},
doi = {10.3389/fcimb.2019.00432},
pmid = {31921707},
issn = {2235-2988},
abstract = {Chronic periodontitis has a polymicrobial biofilm etiology and interactions between key oral bacterial species, such as Porphyromonas gingivalis and Treponema denticola contribute to disease progression. P. gingivalis and T. denticola are co-localized in subgingival plaque and have been previously shown to exhibit strong synergy in growth, biofilm formation and virulence in an animal model of disease. The motility of T. denticola, although not considered as a classic virulence factor, may be involved in synergistic biofilm development between P. gingivalis and T. denticola. We determined the role of T. denticola motility in polymicrobial biofilm development using an optimized transformation protocol to produce two T. denticola mutants targeting the motility machinery. These deletion mutants were non-motile and lacked the gene encoding the flagellar hook protein of the periplasmic flagella (ΔflgE) or a component of the stator motor that drives the flagella (ΔmotB). The specificity of these gene deletions was determined by whole genome sequencing. Quantitative proteomic analyses of mutant strains revealed that the specific inactivation of the motility-associated gene, motB, had effects beyond motility. There were 64 and 326 proteins that changed in abundance in the ΔflgE and ΔmotB mutants, respectively. In the ΔflgE mutant, motility-associated proteins showed the most significant change in abundance confirming the phenotype change for the mutant was related to motility. However, the inactivation of motB as well as stopping motility also upregulated cellular stress responses in the mutant indicating pleiotropic effects of the mutation. T. denticola wild-type and P. gingivalis displayed synergistic biofilm development with a 2-fold higher biomass of the dual-species biofilms than the sum of the monospecies biofilms. Inactivation of T. denticola flgE and motB reduced this synergy. A 5-fold reduction in dual-species biofilm biomass was found with the motility-specific ΔflgE mutant suggesting that T. denticola periplasmic flagella are essential in synergistic biofilm formation with P. gingivalis.},
}
@article {pmid31921010,
year = {2019},
author = {Durgadevi, R and Abirami, G and Alexpandi, R and Nandhini, K and Kumar, P and Prakash, S and Veera Ravi, A},
title = {Explication of the Potential of 2-Hydroxy-4-Methoxybenzaldehyde in Hampering Uropathogenic Proteus mirabilis Crystalline Biofilm and Virulence.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2804},
doi = {10.3389/fmicb.2019.02804},
pmid = {31921010},
issn = {1664-302X},
abstract = {Proteus mirabilis is an important etiological agent of catheter-associated urinary tract infections (CAUTIs) owing to its efficient crystalline biofilm formation and virulence enzyme production. Hence, the present study explicated the antibiofilm and antivirulence efficacies of 2-hydroxy-4-methoxybenzaldehyde (HMB) against P. mirabilis in a non-bactericidal manner. HMB showed concentration-dependent biofilm inhibition, which was also evinced in light, confocal, and scanning electron microscopic (SEM) analyses. The other virulence factors such as urease, hemolysin, siderophores, and extracellular polymeric substances production as well as swimming and swarming motility were also inhibited by HMB treatment. Further, HMB treatment effectively reduced the struvite/apatite production as well as crystalline biofilm formation by P. mirabilis. Furthermore, the results of gene expression analysis unveiled the ability of HMB to impair the expression level of virulence genes such as flhB, flhD, rsbA, speA, ureR, hpmA, and hpmB, which was found to be in correlation with the results of in vitro bioassays. Additionally, the cytotoxicity analysis divulged the innocuous characteristic of HMB against human embryonic kidney cells. Thus, the present study reports the potency of HMB to act as a promising therapeutic remedy for P. mirabilis-instigated CAUTIs.},
}
@article {pmid31921008,
year = {2019},
author = {Wang, J and Jiao, H and Meng, J and Qiao, M and Du, H and He, M and Ming, K and Liu, J and Wang, D and Wu, Y},
title = {Baicalin Inhibits Biofilm Formation and the Quorum-Sensing System by Regulating the MsrA Drug Efflux Pump in Staphylococcus saprophyticus.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2800},
doi = {10.3389/fmicb.2019.02800},
pmid = {31921008},
issn = {1664-302X},
abstract = {Staphylococcus saprophyticus (S. saprophyticus) is one of the main pathogens that cause serious infection due to its acquisition of antibiotic resistance. The efflux pump decreases antibiotic abundance, and biofilm compromises the penetration of antibiotics. It has been reported that baicalin is a potential agent to inhibit efflux pumps, biofilm formation, and quorum-sensing systems. The purpose of this study was to investigate whether baicalin can inhibit S. saprophyticus biofilm formation and the quorum-sensing system by inhibiting the MsrA efflux pump. First, the mechanism of baicalin inhibiting efflux was investigated by the ethidium bromide (EtBr) efflux assay, measurement of ATP content, and pyruvate kinase (PK) activities. These results revealed that baicalin significantly reduced the efflux of EtBr, the ATP content, and the activity of PK. Moreover, its role in biofilm formation and the agr system was studied by crystal violet staining, confocal laser scanning microscopy, scanning electron microscopy, and real-time polymerase chain reaction. These results showed that baicalin decreased biofilm formation, inhibited bacterial aggregation, and downregulated mRNA transcription levels of the quorum-sensing system regulators agrA, agrC, RNAIII, and sarA. Correlation analysis indicated that there was a strong positive correlation between the efflux pump and biofilm formation and the agr system. We demonstrate for the first time that baicalin inhibits biofilm formation and the agr quorum-sensing system by inhibiting the efflux pump in S. saprophyticus. Therefore, baicalin is a potential therapeutic agent for S. saprophyticus biofilm-associated infections.},
}
@article {pmid31919364,
year = {2020},
author = {Dieltjens, L and Appermans, K and Lissens, M and Lories, B and Kim, W and Van der Eycken, EV and Foster, KR and Steenackers, HP},
title = {Inhibiting bacterial cooperation is an evolutionarily robust anti-biofilm strategy.},
journal = {Nature communications},
volume = {11},
number = {1},
pages = {107},
doi = {10.1038/s41467-019-13660-x},
pmid = {31919364},
issn = {2041-1723},
support = {787932//EC | EU Framework Programme for Research and Innovation H2020 | H2020 Priority Excellent Science | H2020 European Research Council (H2020 Excellent Science - European Research Council)/ ; C32/17/020//KU Leuven (Katholieke Universiteit Leuven)/ ; C24/18/046//KU Leuven (Katholieke Universiteit Leuven)/ ; IDO/11/008//KU Leuven (Katholieke Universiteit Leuven)/ ; FWO- SBO S007019N//Fonds Wetenschappelijk Onderzoek (Research Foundation Flanders)/ ; IWT- SBO 120050//Agentschap voor Innovatie door Wetenschap en Technologie (Agency for Innovation by Science and Technology, Flanders)/ ; },
abstract = {Bacteria commonly form dense biofilms encased in extracellular polymeric substances (EPS). Biofilms are often extremely tolerant to antimicrobials but their reliance on shared EPS may also be a weakness as social evolution theory predicts that inhibiting shared traits can select against resistance. Here we show that EPS of Salmonella biofilms is a cooperative trait whose benefit is shared among cells, and that EPS inhibition reduces both cell attachment and antimicrobial tolerance. We then compare an EPS inhibitor to conventional antimicrobials in an evolutionary experiment. While resistance against conventional antimicrobials rapidly evolves, we see no evolution of resistance to EPS inhibition. We further show that a resistant strain is outcompeted by a susceptible strain under EPS inhibitor treatment, explaining why resistance does not evolve. Our work suggests that targeting cooperative traits is a viable solution to the problem of antimicrobial resistance.},
}
@article {pmid31917539,
year = {2020},
author = {Eddenden, A and Kitova, EN and Klassen, JS and Nitz, M},
title = {An inactive Dispersin B probe for monitoring PNAG production in biofilm formation.},
journal = {ACS chemical biology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acschembio.9b00907},
pmid = {31917539},
issn = {1554-8937},
abstract = {The bacterial exopolysaccharide poly-β-1,6-N-acetylglucosamine is a major extracellular matrix component in biofilms of both Gram-positive and Gram-negative organisms. We have leveraged the specificity of the biofilm-dispersing glycoside hydrolase Dispersin B (DspB) to generate a probe (Dispersin B PNAG probe, DiPP) for monitoring PNAG production and localization during biofilm formation. Mutation of the active site of Dispersin B gave DiPP which was an effective probe despite its low affinity for PNAG oligosaccharides, observed in fluorescence quenching and mass spectrometry binding experiments. Imaging of PNAG-dependent and -independent biofilms stained with a fluorescent-protein fusion of DiPP (GFP-DiPP) demonstrated the specificity of the probe for the structure of PNAG on both single-cell and biofilm levels. Through quantitative bacterial cell binding assays and confocal microscopy analysis using GFP-DiPP, discrete areas of local high concentrations of PNAG were detected on the surface of early log phase cells. These distinct areas were seen to grow, slough from cells and accumulate in interbacterial regions over the course of several cell divisions, showing the development of a PNAG-dependent biofilm. A potential helical distribution of staining was also noted, suggesting some degree of organization of PNAG production at the cell surface prior to cell aggregation. Together these experiments shed light on the early stages of PNAG dependent biofilm formation and demonstrate the value of a low-affinity-high-specificity probe for monitoring the production of bacterial exopolysaccharides.},
}
@article {pmid31916896,
year = {2020},
author = {Araújo Lima, AV and da Silva, SM and do Nascimento Júnior, JAA and Correia, MDS and Luz, AC and Leal-Balbino, TC and da Silva, MV and Lima, JLDC and Maciel, MAV and Napoleão, TH and de Oliveira, MBM and Paiva, PMG},
title = {Occurrence and Diversity of Intra- and Interhospital Drug-Resistant and Biofilm-Forming Acinetobacter baumannii and Pseudomonas aeruginosa.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2019.0214},
pmid = {31916896},
issn = {1931-8448},
abstract = {Acinetobacter baumannii and Pseudomonas aeruginosa are the most relevant Gram-negative bacteria associated with hospital and opportunistic infections. This study aimed to evaluate the dynamics of drug-resistant A. baumannii and P. aeruginosa and biofilm formers from two public hospitals in northeastern Brazil. One hundred isolates (35 from A. baumannii and 65 from P. aeruginosa) were identified using the automated Vitek®2 Compact method (bioMérieux) and confirmed using the MALDI-TOF (MS) mass spectrometry technique. Molecular experiments were performed by polymerase chain reaction (PCR) to detect the frequency of blaKPC, blaIMP, blaVIM, and blaSHV genes. The biofilm formation potential was evaluated using crystal violet in Luria Bertani Miller and trypticase soy broth culture media under the following conditions: at standard concentration, one quarter (25%) of the standard concentration and supplemented with 1% glucose. In addition, the genetic diversity of the isolates was verified by the ERIC-PCR technique. Isolates presented distinct resistance profiles with a high level of beta-lactam resistance. The highest index of genes detected was blaKPC (60%), followed by blaSHV (39%), blaVIM (8%), and blaIMP (1%). All the isolates were sensitive to the polymyxins tested and formed biofilms at different intensities. Twelve clones of A. baumannii and eight of P. aeruginosa were identified, of which few were indicative of intra- and interhospital dissemination. This study reveals the dispersion dynamics of these isolates in the hospital environment. The results demonstrate the importance of monitoring programs to combat the spread of these pathogens.},
}
@article {pmid31915750,
year = {2019},
author = {Samoilova, Z and Tyulenev, A and Muzyka, N and Smirnova, G and Oktyabrsky, O},
title = {Tannic and gallic acids alter redox-parameters of the medium and modulate biofilm formation.},
journal = {AIMS microbiology},
volume = {5},
number = {4},
pages = {379-392},
doi = {10.3934/microbiol.2019.4.379},
pmid = {31915750},
issn = {2471-1888},
abstract = {Tannic (TA) and gallic (GA) acids are known to have both anti- and prooxidant properties however recently they have been described as potential anti-biofilm agents although their mechanisms of action on bacterial cells remain obscure. The aim of our research was to elucidate the role of prooxidant actions of these plant phenolic compounds in bactericidal effects and biofilm formation. In our experiments, both compounds demonstrated strong oxidative properties that altered activity of stress regulons and contributed to decrease of CFU and ability of cells to maintain membrane potential. Stimulation of biofilm formation was observed in all the strains with the exception of the strains deficient in flagella synthesis. Both compounds demonstrated bactericidal effect which was weakened in biofilms. TA efficiently killed bacteria in the bioflms of pgaA mutant which pointed out an important role of poly-beta-1,6-N-acetyl-D-glucosamine (PGA) polysaccharide in matrix formation. Similar effects of TA in recA mutant indicate involvement of SOS-response into reaction towards exposure with TA. Gallic acid-induced killing was more pronounced in the biofilms of csgA mutant revealing role of curli in protection against GA toxicity.},
}
@article {pmid31913459,
year = {2020},
author = {Oanh, NT and Duc, HD and Ngoc, DTH and Thuy, NTD and Hiep, NH and Van Hung, N},
title = {Biodegradation of propanil by Acinetobacter baumannii DT in a biofilm-batch reactor and effects of butachlor on the degradation process.},
journal = {FEMS microbiology letters},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsle/fnaa005},
pmid = {31913459},
issn = {1574-6968},
abstract = {The herbicide, propanil, has been extensively applied in weed control, which causes serious environmental pollution. Acinetobacter baumannii DT isolated from soil and has been used to determine the degradation rates of propanil and 3,4-dichloroaniline by freely suspended and biofilm cells. The results showed that the bacterial isolate could utilize both compounds as sole carbon and nitrogen sources. Edwards's model could be fitted well to the degradation kinetics of propanil, with the maximum degradation of 0.027 ± 0.003 mM h-1. The investigation of the degradation pathway showed that A. baumannii DT transformed propanil to 3,4-dichloroaniline before being completely degraded via the ortho-cleavage pathway. In addition, A. baumannii DT showed high tolerance to butachlor, an herbicide usually mixed with propanil to enhance weed control. The presence of propanil and butachlor in the liquid media increased the cell surface hydrophobicity and biofilm formation. Moreover, the biofilm reactor showed increased degradation rates of propanil and butachlor and high tolerance of bacteria to these chemicals. The obtained results showed that A. baumannii DT has a high potential in the degradation of propanil.},
}
@article {pmid31911489,
year = {2020},
author = {Prades, L and Fabbri, S and Dorado, AD and Gamisans, X and Stoodley, P and Picioreanu, C},
title = {Computational and Experimental Investigation of Biofilm Disruption Dynamics Induced by High-Velocity Gas Jet Impingement.},
journal = {mBio},
volume = {11},
number = {1},
pages = {},
doi = {10.1128/mBio.02813-19},
pmid = {31911489},
issn = {2150-7511},
abstract = {Experimental data showed that high-speed microsprays can effectively disrupt biofilms on their support substratum, producing a variety of dynamic reactions such as elongation, displacement, ripple formation, and fluidization. However, the mechanics underlying the impact of high-speed turbulent flows on biofilm structure is complex under such extreme conditions, since direct measurements of viscosity at these high shear rates are not possible using dynamic testing instruments. Here, we used computational fluid dynamics simulations to assess the complex fluid interactions of ripple patterning produced by high-speed turbulent air jets impacting perpendicular to the surface of Streptococcus mutans biofilms, a dental pathogen causing caries, captured by high-speed imaging. The numerical model involved a two-phase flow of air over a non-Newtonian biofilm, whose viscosity as a function of shear rate was estimated using the Herschel-Bulkley model. The simulation suggested that inertial, shear, and interfacial tension forces governed biofilm disruption by the air jet. Additionally, the high shear rates generated by the jet impacts coupled with shear-thinning biofilm property resulted in rapid liquefaction (within milliseconds) of the biofilm, followed by surface instability and traveling waves from the impact site. Our findings suggest that rapid shear thinning under very high shear flows causes the biofilm to behave like a fluid and elasticity can be neglected. A parametric sensitivity study confirmed that both applied force intensity (i.e., high jet nozzle air velocity) and biofilm properties (i.e., low viscosity and low air-biofilm surface tension and thickness) intensify biofilm disruption by generating large interfacial instabilities.IMPORTANCE Knowledge of mechanisms promoting disruption though mechanical forces is essential in optimizing biofilm control strategies which rely on fluid shear. Our results provide insight into how biofilm disruption dynamics is governed by applied forces and fluid properties, revealing a mechanism for ripple formation and fluid-biofilm mixing. These findings have important implications for the rational design of new biofilm cleaning strategies with fluid jets, such as determining optimal parameters (e.g., jet velocity and position) to remove the biofilm from a certain zone (e.g., in dental hygiene or debridement of surgical site infections) or using antimicrobial agents which could increase the interfacial area available for exchange, as well as causing internal mixing within the biofilm matrix, thus disrupting the localized microenvironment which is associated with antimicrobial tolerance. The developed model also has potential application in predicting drag and pressure drop caused by biofilms on bioreactor, pipeline, and ship hull surfaces.},
}
@article {pmid31911315,
year = {2019},
author = {Islam, J and Chilkoor, G and Jawaharraj, K and Dhiman, SS and Sani, R and Gadhamshetty, V},
title = {Vitamin-C-enabled reduced graphene oxide chemistry for tuning biofilm phenotypes of methylotrophs on nickel electrodes in microbial fuel cells.},
journal = {Bioresource technology},
volume = {300},
number = {},
pages = {122642},
doi = {10.1016/j.biortech.2019.122642},
pmid = {31911315},
issn = {1873-2976},
abstract = {This study reports the use of multi-layered reduced graphene oxide (rGO) coating on porous nickel foam (NF) electrodes for enhancing biofilm growth of Rhodobacter Sphaeroides spp fed with methanol in microbial fuel cells (CH3OH-MFCs). Electrochemical methods were used to assess the methylotrophic activity on rGO/NF electrodes. The power density and current density offered by rGO/NF (1200 mW m-2 and 680 mA m-2) were 220-fold and 540-fold higher compared to bare NF (5.50 mW m-2 and 1.26 mA m-2), respectively. Electrochemical impedance spectroscopy results show that rGO/NF suppresses charge transfer resistance to CH3OH oxidation by 40-fold compared to the control. This improved performance is due to the ability of rGO coatings to decrease the wetting contact angle (improve the hydrophilicity) of NF from 1280 to 00. A preliminary cost analysis was carried out to assess the viability of rGO/NF electrodes via vitamin-C-enabled graphene oxide chemistry for CH3OH-MFCs applications.},
}
@article {pmid31910883,
year = {2020},
author = {Omidi, M and Firoozeh, F and Saffari, M and Sedaghat, H and Zibaei, M and Khaledi, A},
title = {Ability of biofilm production and molecular analysis of spa and ica genes among clinical isolates of methicillin-resistant Staphylococcus aureus.},
journal = {BMC research notes},
volume = {13},
number = {1},
pages = {19},
doi = {10.1186/s13104-020-4885-9},
pmid = {31910883},
issn = {1756-0500},
abstract = {OBJECTIVE: This study aimed to evaluate the phenotypic and genotypic characterization of biofilm formation and spa and ica genes among clinical isolates of methicillin-resistant Staphylococcus aureus.<br><br>RESULT: This cross-sectional study was performed on 146 Staphylococcus aureus isolates from hospitalized patients in Isfahan Province Hospitals. MRSA isolates were confirmed using disk diffusion test with oxacillin disk and amplification of mecA gene by PCR assays. Ability of biofilm production was evaluated targeting the icaA and icaD genes. Of 146 Staphylococcus aureus isolates, 24 (16.4%) carried mecA genes and identified as MRSA strains. Strong ability of biofilm production was seen among 76.02% (111/146) S. aureus isolates and 87.5% (21/24) MRSA strains, respectively. Also, 75.0% (18/24) MRSA isolates carried icaA and icaD was not detected in these strains. Analysis of spa gene showed 70.83% (17/24) MRSA strains were spa positive. From which 14 and 3 strains identified with one band (150, 270, 300, 360, 400 bp) and two bands (150-300 bp), respectively. According to data obtained, the prevalence of MRSA isolates from Isfahan Province Hospitals is relatively high and a remarkable percentage of them show strong power in biofilm production. Also analysis of spa gene showed a fairly large diversity among MRSA strains.},
}
@article {pmid31907602,
year = {2020},
author = {Chen, G and Song, W and Ying, X},
title = {Horizontal Gene Transfer of Short-Chain Dehydrogenase Coding Genes Contribute to the Biofilm Formation and Pathogenicity on Mycobacterium grossiae sp. nov. PB739T (=DSM 104744T).},
journal = {Current microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00284-019-01832-3},
pmid = {31907602},
issn = {1432-0991},
support = {2016F10025//Science and technology department of Zhejiang Province/ ; },
abstract = {Mycobacterium grossiae sp. nov. of type strain PB739T is a Gram-positive acid-alcohol-fast rod-shaped bacterium, which was recently isolated from a 76-year-old male who suffered from a 1-year history of hemoptysis. This strain was described as novel species in Mycobacterium genus. In this study, its genome was completely sequenced by PacBio technology, analyzed, and compared with other selected complete genome sequences of Mycobacterium to elucidate the distinct pathogenic features of the strain. The genomic analysis revealed that the genome of PB739T consists of one circular DNA chromosome of 5,637,923 bp with a GC content of 70.48% and one plasmid of 43,679 bp with a GC content of 66.24%. The entire genome contains 5434 predicted coding genes, 48 tRNAs, and 6 rRNA genes. Genome and comparative genomics against M. grossiae SCH identified three tandem short-chain dehydrogenase (SDR) genes which only exist in PB739T. These three tandem SDR genes locate in a Genomic island which was identified by Island Viewer. These SDR genes were predicted to be horizontally transferred from a Streptomyces ancestor based on phylogeny. Analysis of the mutant ΔSDR confirmed the relationship between these tandem genes with biofilm and pathogenicity. This report will provide us with an extended understanding of M. grossiae at the genomic level and would be helpful for understanding the evolution of Mycobacterium genus.},
}
@article {pmid31906541,
year = {2020},
author = {Shokeen, B and Park, J and Duong, E and Rambhia, S and Paul, M and Weinberg, A and Shi, W and Lux, R},
title = {Role of FAD-I in Fusobacterial Interspecies Interaction and Biofilm Formation.},
journal = {Microorganisms},
volume = {8},
number = {1},
pages = {},
doi = {10.3390/microorganisms8010070},
pmid = {31906541},
issn = {2076-2607},
support = {R01DE018276/GF/NIH HHS/United States ; R01DE021108/NH/NIH HHS/United States ; },
abstract = {: RadD, a major adhesin of oral fusobacteria, is part of a four-gene operon encoding the small lipoprotein FAD-I and two currently uncharacterized small proteins encoded by the rapA and rapB genes. Previously, we described a role for FAD-I in the induction of human B-defensin 2 (hBD2) upon contact with oral epithelial cells. Here, we investigated potential roles for fad-I, rapA, and rapB in interspecies interaction and biofilm formation. Gene inactivation mutants were generated for each of these genes in the nucleatum and polymorphum subspecies of Fusobacteriumnucleatum and characterized for their adherence to partner species, biofilm formation, and operon transcription. Binding to Streptococcusgordonii was increased in all mutant strains with Δfad-I having the most significant effect. This increased adherence was directly proportional to elevated radD transcript levels and resulted in significantly different architecture and height of the biofilms formed by Δfad-I and S.gordonii compared to the wild-type parent. In conclusion, FAD-I is important for fusobacterial interspecies interaction as its lack leads to increased production of the RadD adhesin suggesting a role of FAD-I in its regulation. This regulatory effect does not require the presence of functional RadD.},
}
@article {pmid31906465,
year = {2020},
author = {Pompilio, A and Savini, V and Fiscarelli, E and Gherardi, G and Di Bonaventura, G},
title = {Clonal Diversity, Biofilm Formation, and Antimicrobial Resistance among Stenotrophomonas maltophilia Strains from Cystic Fibrosis and Non-Cystic Fibrosis Patients.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {9},
number = {1},
pages = {},
doi = {10.3390/antibiotics9010015},
pmid = {31906465},
issn = {2079-6382},
support = {Fondo Ricerca di Ateneo, anno 2017//Università degli Studi G. d'Annunzio Chieti - Pescara/ ; },
abstract = {The intrinsic antibiotic resistance of Stenotrophomonas maltophilia, along with its ability to form biofilm both on abiotic surfaces and host tissues, dramatically affects the efficacy of the antibiotic therapy. In this work, 85 S. maltophilia strains isolated in several hospital of central Italy and from several clinical settings were evaluated for their genetic relatedness (by pulsed-field gel electrophoresis, PFGE), biofilm formation (by microtiter plate assay), and planktonic antibiotic resistance (by Kirby-Bauer disk diffusion technique). The S. maltophilia population showed a high genetic heterogeneity: 64 different PFGE types were identified, equally distributed in cystic fibrosis (CF) and non-CF strains, and some consisted of multiple strains. Most of the strains (88.2%) were able to form biofilm, although non-CF strains were significantly more efficient than CF strains. CF strains produced lower biofilm amounts than non-CF strains, both those from respiratory tracts and blood. Non-CF PFGE types 3 and 27 consisted of strong-producers only. Cotrimoxazole and levofloxacin were the most effective antibiotics, being active respectively against 81.2% and 72.9% of strains. CF strains were significantly more resistant to piperacillin/tazobactam compared to non-CF strains (90% versus 53.3%), regardless of sample type. Among respiratory strains, cotrimoxazole was more active against non-CF than CF strains (susceptibility rates: 86.7% versus 75%). The multidrug resistant phenotype was significantly more prevalent in CF than non-CF strains (90% versus 66.7%). Overall, the multidrug-resistance level was negatively associated with efficiency in biofilm formation. Our results showed, for the first time, that in S. maltophilia both classical planktonic drug resistance and the ability of biofilm formation might favor its dissemination in the hospital setting. Biofilm formation might in fact act as a survival mechanism for susceptible bacteria, suggesting that clinical isolates should be routinely assayed for biofilm formation in diagnostic laboratories.},
}
@article {pmid31905828,
year = {2019},
author = {Ishchuk, OP and Sterner, O and Ellervik, U and Manner, S},
title = {Simple Carbohydrate Derivatives Diminish the Formation of Biofilm of the Pathogenic Yeast Candida albicans.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {9},
number = {1},
pages = {},
doi = {10.3390/antibiotics9010010},
pmid = {31905828},
issn = {2079-6382},
support = {--//Stiftelsen Lars Hiertas Minne/ ; --//Magnus Bergvalls Stiftelse/ ; --//Lunds Universitet/ ; --//The Sten K. Johnson Foundation/ ; --//Kungliga Fysiografiska Sällskapet i Lund/ ; },
abstract = {The opportunistic human fungal pathogen Candida albicans relies on cell morphological transitions to develop biofilm and invade the host. In the current study, we developed new regulatory molecules, which inhibit the morphological transition of C. albicans from yeast-form cells to cells forming hyphae. These compounds, benzyl α-l-fucopyranoside and benzyl β-d-xylopyranoside, inhibit the hyphae formation and adhesion of C. albicans to a polystyrene surface, resulting in a reduced biofilm formation. The addition of cAMP to cells treated with α-l-fucopyranoside restored the yeast-hyphae switch and the biofilm level to that of the untreated control. In the β-d-xylopyranoside treated cells, the biofilm level was only partially restored by the addition of cAMP, and these cells remained mainly as yeast-form cells.},
}
@article {pmid31905318,
year = {2020},
author = {Sousa, CA and Taborda, MBB and Momesso, GC and Rocha, EP and Dos Santos, PH and Santigo-Junior, JF and Assunçao, WG},
title = {Materials Sealing Preventing Biofilm Formation in Implant/Abutment Joints: Which Is the Most Effective? A Systematic Review and Meta-Analysis.},
journal = {The Journal of oral implantology},
volume = {},
number = {},
pages = {},
doi = {10.1563/aaid-joi-D-19-00121},
pmid = {31905318},
issn = {0160-6972},
abstract = {The purpose of this systematic review was to evaluate the literature available for materials exhibiting the best efficacy in preventing biofilm formation in the interior of implants. We searched PubMed/MEDLINE, Scopus, and Cochrane databases. This review is registered with the PROSPERO database and followed the suitability of the PRISMA protocol. The initial search resulted in 326 articles from the databases. After they were read, eight articles remained and the inclusion and exclusion criteria were applied. Six of these eight articles were classified as in vitro and two were classified as in situ. The regions of the implants evaluated ranged from the interface of the pieces to the occlusal upper access of the abutment. The implant connections evaluated the Morse taper, external and internal connection. Meta-analysis of the quantitative data was performed at the significance level of 0.05. Cotton exhibited poor control of infiltration, even in combination with other materials. Isolated gutta-percha (GP) and polytetrafluoroethylene (PTFE) tape with composite resin (CR) or GP performed better as physical barriers. The best results for chemical barriers were observed by the application of 1% chlorhexidine gluconate (CG) gel, thymol varnish, and the deposition of Ag films onto the surface. The applied meta-analysis did not show a significant difference in comparison between the different types of implant connections (p>0.05). The application of CG and thymol varnish antimicrobials was effective in preventing biofilm formation and easy clinical execution; these could be used in combination with CR, GP, and PTFE.},
}
@article {pmid31904552,
year = {2020},
author = {Ghorbanzadeh, A and Bahador, A and Sarraf, P and Ayar, R and Fekrazad, R and Asefi, S},
title = {Ex Vivo Comparison of Antibacterial Efficacy of Conventional Chemomechanical Debridement Alone and in Combination with Light-Activated Disinfection and Laser Irradiation Against Enterococcus Faecalis Biofilm.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {101648},
doi = {10.1016/j.pdpdt.2019.101648},
pmid = {31904552},
issn = {1873-1597},
abstract = {BACKGROUND AND OBJECTIVES: Intracanal disinfection plays an important role in endodontic treatment success. Enterococcus faecalis (E. faecalis) is a resistant microorganism responsible for endodontic infections. We aimed to assess the bactericidal effects of three disinfection methods on E. faecalis biofilm.<br><br>MATERIALS AND METHODS: Fifty-five freshly extracted single-rooted human teeth were evaluated. A barbed broach was used to extract the pulp tissue. No further root canal preparation was performed. Specimens were sterilized with gamma radiation, and inoculated with E. faecalis suspension. They were then incubated for 4 days and 4 weeks. Biofilm formation was confirmed using a scanning electron microscope (SEM). The teeth were randomly assigned to three subgroups (n = 7) to assess the antimicrobial efficacy of the following three disinfection methods against immature (4-day) and mature (4-week) biofilms: the conventional chemomechanical debridement (CCMD), CCMD + light-activated disinfection (LAD; 810 nm, 0.3 W, 120 J/cm2) with indocyanine Green (EmunDo) as photosensitizer and CCMD + diode laser irradiation (810 nm, 2 W). The teeth were then longitudinally split into two halves and the colony count was reported as colony forming units (CFUs) to assess bacterial viability after each disinfection protocol.<br><br>RESULTS: None of the disinfection methods could completely remove the biofilm. CCMD + LAD caused the highest and CCMD + diode laser caused the lowest reduction in biofilm. Antibacterial efficacy was significantly lower against the mature (4-week) biofilm compared with immature (4-day) biofilm in all groups (P < 0.05).<br><br>CONCLUSION: All three disinfection methods were effective for partial elimination of E. faecalis biofilm. But CCMD + LAD was significantly more efficacious in decreasing both mature and immature biofilms.},
}
@article {pmid31904447,
year = {2020},
author = {Ponce-Angulo, DG and Bautista-Hernández, LA and Calvillo-Medina, RP and Castro-Tecorral, FI and Aparicio-Ozores, G and López-Villegas, EO and Ribas-Aparicio, RM and Bautista de Lucio, VM},
title = {Microscopic characterization of biofilm in mixed keratitis in a novel murine model.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103953},
doi = {10.1016/j.micpath.2019.103953},
pmid = {31904447},
issn = {1096-1208},
abstract = {PURPOSE: To report the characterization and analysis of the biofilm formation in mixed keratitis induced by the coinfection of Staphylococcus aureus and Fusarium falciforme in a novel murine model.<br><br>METHODS: Clinical ocular microbial isolates and female BALB/c mice were used to develop the murine model. Immunosuppression was achieved with cyclophosphamide and methylprednisolone. A corneoscleral lesion was performed with a micro-pocket technique. Mice received an inoculum with a concentration of 1 × 105 conidia of F. falciforme and S. aureus with 1 × 105 UFC/ml. Mice were sacrificed at 72 h after induction of infection, the right eye was enucleated and preserved in 10% formaldehyde to perform the PAS staining. In addition, cuts were obtained for the labeling with the fluorophores propidium iodide and Calcofluor White, and other eye cuts were processed to transmission microscopy.<br><br>RESULTS: F. falciforme and S. aureus were able to developed mono and mixed biofilm in vitro. Keratitis of F. falciforme, S. aureus and mixed, were established at immunosuppressed mice. Clinical symptoms were observed at murine cornea. Histological analysis by special stains identified bacterial, fungal and mixed biofilm structures at epithelial and stromal level. Extracellular matrix was observed surrounded clusters of bacterial, fungi and mixed by fluorescence and transmission electronic microscopy.<br><br>CONCLUSION: This study provides direct evidence of the establishment and formation of mixed biofilm in vitro, as well as in vivo on the corneal surface of mice in an experimentally induced S. aureus and F. falciforme mixed keratitis infection.},
}
@article {pmid31903886,
year = {2020},
author = {Kheiri, F and Kermanshahi, RK and Feizabadi, MM},
title = {The Inhibitory Effects of Lactobacillus Supernatants and Their Metabolites on the Growth and Biofilm Formation of Klebsiella pneumoniae.},
journal = {Infectious disorders drug targets},
volume = {},
number = {},
pages = {},
doi = {10.2174/1871526520666200106122632},
pmid = {31903886},
issn = {2212-3989},
abstract = {BACKGROUND: Klebsiella pneumoniae is a common cause of hospital acquired infections including urinary tract infection (UTI). Biofilm formation makes the K. pneumoniae infection more complicated and carrying extended spectrum beta-lactamases (ESBLs) genes limits antibiotic choices for treatment. Lactobacillus strains are known as natural protective barriers against UTIs.<br><br>OBJECTIVES: This is a small in-vitro study aimed to determine the effect of probiotic Lactobacillus strains and some types of their metabolites on the growth and biofilm of UTI isolated and reference strain of Klebsiella pneumoniae.<br><br>METHODS: The efficacy of Lactobacillus supernatants and antibiotics in prevention and elimination of K. pneumoniae biofilms was determined using a quantitative adherence assay. A rapid colorimetric microplate bioassay was applied for detection of survived bacterial cells after treatment with antibacterial agents. Biofilm phenotypes were studied by scanning electron microscopy (SEM).<br><br>RESULTS: The results showed that seven out of eight ESBL producing uropathogenic K. pneumoniae isolates in this study were able to produce biofilm. Lactobacillus supernatants at 1:1 to 1:16 dilutions, had more than 95% biofilm-inhibitory and biofilm-killing properties on strong biofilm producer isolate. Supra-MIC levels of antibiotics had much lower anti-biofilm effect than Lactobacillus supernatant and left considerable alive biofilm cells.<br><br>CONCLUSIONS: Although antibiotic resistance increases in biofilm forms of Klebsiella pneumoniae, Lactobacillus supernatants have strong antibiofilm efficacy even in concentrations lower than MIC. Biofilm formation decreases considerably in the presence of Lactobacillus supernatants. Hydrogen peroxide is an effective product against growth and biofilm formation of Klebsiella pneumoniae.},
}
@article {pmid31902639,
year = {2019},
author = {Leyva-Díaz, JC and Monteoliva-García, A and Martín-Pascual, J and Munio, MM and García-Mesa, JJ and Poyatos, JM},
title = {Moving bed biofilm reactor as an alternative wastewater treatment process for nutrient removal and recovery in the circular economy model.},
journal = {Bioresource technology},
volume = {},
number = {},
pages = {122631},
doi = {10.1016/j.biortech.2019.122631},
pmid = {31902639},
issn = {1873-2976},
abstract = {Over the last years, an increasing concern has emerged regarding the eco-friendly management of wastewater. Apart from the role of wastewater treatment plants (WWTPs) for wastewater and sewage sludge treatment, the increasing need of the recovery of the resources contained in wastewater, such as nutrients and water, should be highlighted. This would allow for transforming a wastewater treatment plant (WWTP) into a sustainable technological system. The objective of this review is to propose a moving bed biofilm reactor (MBBR) as a novel technology that contributes to the circularity of the wastewater treatment sector according to the principles of circular economy. In this regard, this paper aims to consider the MBBR process as the initial step for water reuse, and nutrient removal and recovery, within the circular economy model.},
}
@article {pmid31902502,
year = {2020},
author = {Aper, D and Frömbling, J and Bağcıoğlu, M and Ehling-Schulz, M and Hennig-Pauka, I},
title = {Comparison of metabolic adaptation and biofilm formation of Actinobacillus pleuropneumoniae field isolates from the upper and lower respiratory tract of swine with respiratory disease.},
journal = {Veterinary microbiology},
volume = {240},
number = {},
pages = {108532},
doi = {10.1016/j.vetmic.2019.108532},
pmid = {31902502},
issn = {1873-2542},
abstract = {Most outbreaks of disease due to infection with Actinobacillus (A.) pleuropneumoniae are caused by pigs already pre-colonised in tonsillar tissue, where the pathogen is protected from exposure to antibiotic substances administered for treatment. As it has been shown recently under experimental conditions, A. pleuropneumoniae displays host tissue-specific metabolic adaptation. In this study, pairs of A. pleuropneumoniae field isolates were recovered from lung as well as from tonsillar and nasal tissue from 20 pigs suffering from acute clinical signs of pleuropneumonia and showing characteristic pathological lung alterations. Metabolic adaptation to the porcine lower and upper respiratory tract of 32 A. pleuropneumoniae serotype 2 field isolates was examined using Fourier transform infrared (FTIR) spectroscopy as a high resolution metabolic fingerprinting method. All strains showed metabolic adaptations to organ tissue reflected by hierarchical cluster analysis of FTIR spectra similar to those previously observed under experimental conditions. Notably, differences in antimicrobial resistance patterns and minimal inhibitory concentrations of isolates from different tissues in the same animal, but not in biofilm production capability in a microtiter plate assay were found. Overall, biofilm formation was observed for 71 % of the isolates, confirming that A. pleuropneumoniae field isolates are generally able to form biofilms, although rather in a serotype-specific than in an organ-specific manner. A. pleuropneumoniae serotype 6 isolates formed significantly more biofilm than the other serotypes. Furthermore, biofilm production was negatively correlated to the lung lesion scores and tonsillar isolates tended to be more susceptible to antimicrobial substances with high bioavailability than lung isolates.},
}
@article {pmid31902330,
year = {2020},
author = {Liu, Y and Zhang, J and Ji, Y},
title = {Environmental factors modulate biofilm formation by Staphylococcus aureus.},
journal = {Science progress},
volume = {},
number = {},
pages = {36850419898659},
doi = {10.1177/0036850419898659},
pmid = {31902330},
issn = {2047-7163},
abstract = {Biofilm formation on indwelling medical devices represents an exclusive evasion mechanism for many pathogenic bacteria to establish chronic infections. Staphylococcus aureus is one of the major bacterial pathogens that are able to induce both animal and human infections. The continued emergence of multiple drug-resistant S. aureus, especially methicillin-resistant S. aureus, is problematic due to limited treatment options. Biofilm formation by S. aureus complicates the treatment of methicillin-resistant S. aureus infections. Therefore, elucidating the mechanisms of biofilm formation in this pathogen is important for the development of alternative therapeutic strategies. Various environmental and genetic factors contribute to biofilm formation. In this review, we address the environmental factors and discuss how they affect biofilm formation by S. aureus.},
}
@article {pmid31901662,
year = {2019},
author = {Shah, T and Munsif, F and D'amato, R and Nie, L},
title = {Lead toxicity induced phytotoxic impacts on rapeseed and clover can be lowered by biofilm forming lead tolerant bacteria.},
journal = {Chemosphere},
volume = {246},
number = {},
pages = {125766},
doi = {10.1016/j.chemosphere.2019.125766},
pmid = {31901662},
issn = {1879-1298},
abstract = {Lead (Pb+2) is a heavy metal and one of the main environmental pollutant, toxic to plants, animals and humans. Present study was conducted to evaluate ten plant growth promoting bacteria strains (B1-10) for biofilm production and their effect on growth indices, physiology, yield, antioxidant profile and lead uptake in rapeseed (Brassica napus) and clover (Trifolium repens) in lead polluted soil under nutrient broth medium and pot condition. Three pre-characterized biofilm forming lead tolerant growth promoting strains (B3: Pseudomonas fluorescens), B6: Pseudomonas putida and (B8: Bacillus safensis) were used to inoculate rapeseed and clover growing in the soil polluted with different levels (400, 800 and 1200 mg kg-1) of Pb arranged in completely randomized design with factorial arrangement. Results from screening experiment exhibited that more biofilm was produced by B3, B6 and B8 under highest level of lead contamination (1200 mg kg-1). Further, lead contamination decreased rapeseed and clover growth, physiology and yield at all levels of lead stress. But biofilm forming lead tolerant growth promoting bacteria application in lead contaminated soil enhanced rapeseed and clover growth, physiology, yield, antioxidant profile, proline and decreased malanodialdehyde content (which was decreased by different strains application under lead stress) of rapeseed and clover over no inoculation. Inoculation with all strains also increased the lead uptake in roots, shoots and decreased lead uptake in seeds of rapeseed and clover than plants in lead stress without inoculation.},
}
@article {pmid31897448,
year = {2018},
author = {Wilson, C and Brigham, B and Sandoval, J and Sabatka, D and Wilson, E and Sebest, C and Schofield, BJ and Holmes, AE and Sutlief, AL},
title = {The Quantitative Assessment of Pseudomonas aeruginosa (PA)14 Biofilm Surface Coverage on Slippery Liquid Infused Polymer Surfaces (SLIPS).},
journal = {International journal of nanotechnology in medicine &amp; engineering},
volume = {3},
number = {3},
pages = {35-42},
pmid = {31897448},
issn = {2474-8811},
abstract = {Slippery, porous polymeric antimicrobial surfaces for biofilm attachment inhibition of the clinical strain Pseudomonas aeruginosa (PA14) have been prepared. Porous BMA-EDMA, characterized for its hydrophobic properties, was infused with a slippery liquid creating a hydrophobic liquid interface and characterized by water contact angle and SEM. A low shear force bioreactor was used to prepare biofilms on these antimicrobial surfaces. Biofilm attachment was studied using fluorescence microscopy coupled with image analysis in ImageJ. While the literature presents that these slippery polymers work well as antimicrobial surfaces for several strains of Pseudomonas aeruginosa, it has been found to be strain dependent. This report demonstrates that slippery surfaces do not work well for the strain PA14, and biofilm covered >3.5 times more area as compared to the control glass surfaces.},
}
@article {pmid31899382,
year = {2019},
author = {Ghorbanzadeh, R and Assadian, H and Chiniforush, N and Parker, S and Pourakbari, B and Ehsani, B and Alikhani, MY and Bahador, A},
title = {Modulation of virulence in Enterococcus faecalis cells surviving antimicrobial photodynamic inactivation with reduced graphene oxide-curcumin; an ex vivo biofilm model.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {101643},
doi = {10.1016/j.pdpdt.2019.101643},
pmid = {31899382},
issn = {1873-1597},
abstract = {BACKGROUND: Enterococcus faecalis, as a major microorganism in persistent/secondary infections of endodontically treated teeth, is less likely to be eliminated during endodontic therapy. In this study, the effect of root canal disinfection and anti-virulence activities of photodynamic inactivation (PDI) of E. faecalis utilizing reduced graphene oxide-curcumin (rGO-Cur) as a photosensitizing agent following irradiation with light-emitting diode (LED), as well as intracellular ROS production were evaluated on ex vivo biofilms of E. faecalis in comparison with sodium hypochlorite (NaOCl) as the traditional endodontic irrigation solution.<br><br>MATERIALS AND METHODS: After formulation and confirmation of synthesized rGO-Cur using scanning electron microscopy (SEM), Fourier transformation infrared (FT-IR), UV-Vis spectra, dynamic light scattering (DLS), and Zeta potential, the minimum biofilm inhibitory concentrations (MBICs) and in vitro anti-biofilm activity of rGO-Cur, light-emitting diode (LED) at the wavelength of 435 ± 20 nm, and rGO-Cur-PDI were determined against 4-week-old pre-formed biofilms of E. faecalis. After preparation of ex vivo biofilm model in root canals, the ex-vivo anti-biofilm potential of rGO-Cur, LED, and rGO-Cur-PDI against E. faecalis were analyzed using the XTT assay and scanning electron microscopy (SEM) in comparison with NaOCl. The effects of sub-MBIC of rGO-Cur and NaOCl, sub-lethal dose of LED, and sub-significant inhibitory (SSI) potential of rGO-Cur-PDI for E. faecalis biofilms on virulence genes (efa, esp, gel, and fsr) expression of E. faecalis were analyzed using real-time polymerase chain reaction (qRT-PCR) assay. Intracellular reactive oxygen species (ROS) level was measured in rGO-Cur-PDI-treated bacterial cells compared to control cells with 2',7'-dichlorfluorescein-diacetate (DCFH-DA) fluorescent probe.<br><br>RESULTS: The FTIR, DLS, Zeta potential, SEM, and UV-Vis spectra analysis indicated the successful synthesis of rGO-Cur. The MBIC of rGO-Cur was 250 µg/ml, which inhibited the growth ofE. faecalis. LED showed insignificant anti-biofilm activity against E. faecalis even after treating for a long irradiation time (300 sec). According to checkerboard assay, the MBIC value of rGO-Cur-PDI was reduced noticeably compared to the individual MBIC values of rGO-Cur and LED for E. faecalis. The expression levels of efa, esp, gel, and fsr genes in pre-formed E. faecalis biofilms were markedly reduced after rGO-Cur, rGO-Cur-PDI, and NaOCl treatment in comparison with the control group. Conversely, LED revealed no significant change in the expression of the virulence genes. The intracellular ROS assay showed a significant increase (8.3-fold) in rGO-Cur-PDI when compared to the control.<br><br>CONCLUSION: Our data support that rGO-Cur-PDI showed dual inhibitory effects on biofilm formation ability and virulence activity of E. faecalis with potential clinical applications for infection control in endodontics.},
}
@article {pmid31899376,
year = {2019},
author = {Abdulrahman, H and Misba, L and Ahmad, S and Khan, AU},
title = {Curcumin induced photodynamic therapy mediated suppression of quorum sensing pathway of Pseudomonas aeruginosa: An approach to inhibit biofilm in vitro.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {101645},
doi = {10.1016/j.pdpdt.2019.101645},
pmid = {31899376},
issn = {1873-1597},
abstract = {OBJECTIVE: The objective of this study was to inhibit thePseudomonas aeruginosa biofilm through curcumin-mediated antimicrobial photodynamic therapy (APDT).<br><br>BACKGROUND: The mechanism behind APDT mediated photoinactivation depend upon reactive oxygen species (ROS) production, like singlet oxygen and free radicles.<br><br>METHODS: To evaluate the antibacterial efficacy of curcumin induced APDT onP. aeruginosa by colony forming unit (CFU) while antibiofilm action was determined by the use of crystal violet, XTT, congored binding assay and confocal laser scanning microscope (CLSM).<br><br>RESULTS: We found that curcumin with 10 J/cm2 of light reduces P. aeruginosa biofilm more efficiently than without light. Extracellular polymeric substances (EPS) production was also reduced by approx 94% with 10 J/cm2 of light dose. CLSM images showed that the thickness of biofilms were reduced from >30 µm to <5 µm after treatment with curcumin followed by 10 J/cm2 of light irradiation. Curcumin showed better bacteriostatic activity than bactericidal activity. Singlet oxygen is primarily responsible for photodamage and cytotoxic reactions caused by curcumin-mediated APDT. Genes involved in quorum sensing (QS) pathway was also found to be inhibited after APDT. Curcumin with 5 J/cm2 light inhibits QS genes and on increasing light dose i.e10 J/cm2, we found a drastic reduction in gene expression.<br><br>CONCLUSION: We conclude that the curcumin mediated APDT inhibits biofilm formation ofP. aeruginosa through QS pathway by the action of singlet oxygen generation which in turn reduced EPS of the biofilm.},
}
@article {pmid31899281,
year = {2019},
author = {SchwarzerS, and Ga, J and D, G and T, B and K, V and Sl, P and P, S and G, S and So, J and M, M},
title = {The efficacy of topical agents used in wounds for managing chronic biofilm infections: A systematic review.},
journal = {The Journal of infection},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jinf.2019.12.017},
pmid = {31899281},
issn = {1532-2742},
abstract = {OBJECTIVES: Clinicians have increasingly adopted the widespread use of topical agents to manage chronic wound infections, despite limited data on their effectiveness in vivo. This study sought to evaluate the evidence for commonly employed topical agents used in wounds for the purpose of treating chronic infections caused by biofilm.<br><br>METHOD: We included in vitro, animal and human in vivo studies where topical agents were tested for their efficacy against biofilms, for use in wound care. For human studies, we only included those which utilised appropriate identification techniques for visualising and confirming the presence of biofilms.<br><br>RESULT: A total of 640 articles were identified, with 43 included after meeting eligibility. In vitro testing accounted for 90% (n = 39) of all included studies, five studies using animal models and three human in vivo studies. Sixteen different laboratory models were utilised, with the most frequent being the minimum biofilm eradication concentration (MBEC™) / well plate assay (38%, n = 15 of 39). A total of 44 commercially available topical agents were grouped into twelve categories with the most commonly tested agents being silver, iodine and polyhexamethylene biguanide (PHMB). In vitro results on efficacy demonstrated iodine as having the highest mean log10 reductions of all agents (4.81, ±3.14).<br><br>CONCLUSION: There is large disparity in the translation of laboratory studies to researchers undertaking human trials relating to the effectiveness of commercially available topical agents. There is insufficient human in vivo evidence to definitively recommend any commercially available topical agent over another for the treatment of chronic wound biofilms. The heterogeneity identified between study designs (in vitro to in vivo) further limits the generalisability of results.},
}
@article {pmid31898890,
year = {2020},
author = {Soldano, A and Yao, H and Chandler, JR and Rivera, M},
title = {Inhibiting iron mobilization from bacterioferritin in Pseudomonas aeruginosa impairs biofilm formation irrespective of environmental iron availability.},
journal = {ACS infectious diseases},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsinfecdis.9b00398},
pmid = {31898890},
issn = {2373-8227},
abstract = {Although iron is essential for bacteria, the nutrient presents problems of toxicity and solubility. Bacteria circumvent these problems with the aid of iron storage proteins where Fe3+ is deposited, and when necessary, mobilized as Fe2+ for metabolic requirements. In Pseudomonas aeruginosa Fe3+ is compartmentalized in bacterioferritin (BfrB), and its mobilization as Fe2+ requires specific binding of a ferredoxin (Bfd) to reduce the stored Fe3+. Blocking the BfrB-Bfd complex leads to irreversible iron accumulation in BfrB and cytosolic iron deprivation. Consequently, given the intracellular iron sufficiency requirement for biofilm development, we hypothesized that blocking the BfrB-Bfd interaction in P. aeruginosa would impair biofilm development. Our results show that planktonic and biofilm-embedded cells where the BfrB-Bfd complex is blocked exhibit cytosolic iron deficiency, and poorly developed biofilms, even in iron-sufficient culture conditions. These results underscore inhibition of the BfrB-Bfd complex as a rational target to dysregulate iron homeostasis and possibly control biofilms.},
}
@article {pmid31897991,
year = {2020},
author = {Aydin, ME and Beduk, F and Aydin, S and Koyuncu, S and Genuit, G and Bahadir, M},
title = {Development of biofilm collectors as passive samplers in sewerage systems-a novel wastewater monitoring method.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-019-07179-3},
pmid = {31897991},
issn = {1614-7499},
abstract = {In this study, a novel wastewater sampling method based on biofilm collection on a multi-armed polyethylene strips (so called &quot;Octopus&quot;) is proposed. The implementation of this method is a step forward to prevent illegal industrial discharges into sewerage systems and receiving water bodies. Prior applications of biofilm collection were performed in Bielefeld, Germany, in 1994. The success of the method encouraged other municipalities to apply this method for monitoring indirect discharges into sewerage systems. Municipality of Konya, Turkey, started to use the method in 2013. Continuous monitoring has been performed for the determination of regulated heavy metals: chromium (Cr), copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), mercury (Hg) and cadmium (Cd). Unauthorized discharges of Cr, Zn and Ni were identified in Konya by performing sewerage slime tests through biofilm analyses. 2686 mg/kg d.m. Cr, 3949 mg/kg d.m. Zn and 3300 mg/kg d.m. Ni were highest values determined for biofilm samples taken from monitoring sites. In this paper, the principles of the method will be introduced, and findings from the wastewater of Konya City will be given in comparison with findings from Bielefeld, Germany. Conducted results reveal high (and likely illegal) heavy metal discharges into the sewerage system in Konya. The continuous monitoring of sewerage systems with biofilm collectors is an effective and efficient method for point source control of wastewater pollutants.},
}
@article {pmid31896640,
year = {2020},
author = {Boukerb, AM and Simon, M and Pernet, E and Jouault, A and Portier, E and Persyn, E and Bouffartigues, E and Bazire, A and Chevalier, S and Feuilloley, MGJ and Lesouhaitier, O and Caillon, J and Dufour, A},
title = {Draft Genome Sequences of Four Pseudomonas aeruginosa Clinical Strains with Various Biofilm Phenotypes.},
journal = {Microbiology resource announcements},
volume = {9},
number = {1},
pages = {},
doi = {10.1128/MRA.01286-19},
pmid = {31896640},
issn = {2576-098X},
abstract = {Biofilms produced by Pseudomonas aeruginosa present a serious threat to cystic fibrosis patients. Here, we report the draft genome sequences of four cystic fibrosis isolates displaying various mucoid and biofilm phenotypes. The estimated average genome size was about 6,255,986 ± 50,202 bp with a mean G+C content of 66.52 ± 0.06%.},
}
@article {pmid31896623,
year = {2020},
author = {Tram, G and Klare, WP and Cain, JA and Mourad, B and Cordwell, SJ and Korolik, V and Day, CJ},
title = {RNA Sequencing Data Sets Identifying Differentially Expressed Transcripts during Campylobacter jejuni Biofilm Formation.},
journal = {Microbiology resource announcements},
volume = {9},
number = {1},
pages = {},
doi = {10.1128/MRA.00982-19},
pmid = {31896623},
issn = {2576-098X},
abstract = {Campylobacter jejuni is a foodborne pathogen and an important contributor to gastroenteritis in humans. C. jejuni readily forms biofilms which may play a role in the transmission of the pathogen from animals to humans. Herein, we present RNA sequencing data investigating differential gene expression in biofilm and planktonic C. jejuni These data provide insight into pathways which may be important to biofilm formation in this organism.},
}
@article {pmid31896192,
year = {2020},
author = {Li, W and Tan, Q and Zhou, W and Chen, J and Li, Y and Wang, F and Zhang, J},
title = {Impact of substrate material and chlorine/chloramine on the composition and function of a young biofilm microbial community as revealed by high-throughput 16S rRNA sequencing.},
journal = {Chemosphere},
volume = {242},
number = {},
pages = {125310},
doi = {10.1016/j.chemosphere.2019.125310},
pmid = {31896192},
issn = {1879-1298},
abstract = {The bacterial composition of biofilms in drinking water distribution systems is significantly impacted by the disinfection regime and substrate material. However, studies that have addressed the changes in the biofilm community during the early stage of formation (less than 10 weeks) were not yet adequate. Here, we explore the effects of the substrate materials (cast iron, stainless steel, copper, polyvinyl chloride, and high density polyethylene) and different disinfectants (chlorine and chloramine) on the community composition and function of young biofilm by using 16S rDNA sequencing. The results showed that Alphaproteobacteria (39.14%-80.87%) and Actinobacteria (5.90%-40.03%) were the dominant classes in chlorine-disinfection samples, while Alphaproteobacteria (17.46%-74.18%) and Betaproteobacteria (3.79%-68.50%) became dominant in a chloraminated group. The infrequently discussed genus Phreatobacter became predominant in the chlorinated samples, but it was inhibited by chloramine and copper ions. The key driver of the community composition was indicated as different disinfectants according to principle coordination analysis (PCoA) and Permutational multivariate analysis of variance (Adonis test), and the bacterial community changed significantly over time. Communities of biofilms grown on cast iron showed a great distance from the other materials according to Bray-Curtis dissimilarity, and they had a unique dominant genus, Dechloromonas. A metagenomics prediction based on 16S rDNA was used to detect the functional pathways of antibiotic biosynthesis and beta-lactam resistance, and it revealed that several pathways were significantly different in terms of their chlorinated and chloraminated groups.},
}
@article {pmid31895639,
year = {2019},
author = {Da Cunda, P and Iribarnegaray, V and Papa-Ezdra, R and Bado, I and González, MJ and Zunino, P and Vignoli, R and Scavone, P},
title = {Characterization of the Different Stages of Biofilm Formation and Antibiotic Susceptibility in a Clinical Acinetobacter baumannii Strain.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2019.0145},
pmid = {31895639},
issn = {1931-8448},
abstract = {Acinetobacter baumannii is a relevant opportunistic pathogen, and one of the main microorganisms responsible for outbreaks in nosocomial infections worldwide. Its pathogenicity is mainly due to its resistance to multiple antibiotics and to its ability to form biofilms on abiotic surfaces. The objective of this study was to characterize the biofilm formation cycle of A. baumannii isolated from a patient in a hospital and compare its antibiotic resistance with the planktonic cells. To study biofilm formation, the classical microtiter assay was used, with crystal violet staining and optical density reading to classify the type of biofilm. Also, the effect of gentamicin and colistin on bacterial biofilm was studied with an extra step of antibiotic addition. For the characterization of the different biofilm formation stages, the strain was grown on a coverslip, and the stain was made with a mixture of fluorophores markers to visualize the biofilm with a confocal laser microscope. It was possible to differentiate the A. baumannii biofilm formation stages. Through these observations, it was possible to estimate the time elapsed between each stage. As the strain was susceptible to colistin and gentamicin, both antibiotics were evaluated after the biofilm was formed. Neither antibiotics showed an effect on the eradication of A. baumannii biofilm.},
}
@article {pmid31895006,
year = {2020},
author = {Gu, L and Chen, Q and Guo, A and Liu, W and Ruan, Y and Zhang, X and Nou, X},
title = {Differential Effects of Growth Medium Salinity on Biofilm Formation of Two Salmonella enterica Strains.},
journal = {Journal of food protection},
volume = {},
number = {},
pages = {196-203},
doi = {10.4315/0362-028X.JFP-19-418},
pmid = {31895006},
issn = {1944-9097},
abstract = {Salmonella enterica is a prominent foodborne pathogen, including diverse serotypes that are prolific biofilm formers. Its ability to form biofilm can be affected by multiple environmental factors. In this study, the effect of salinity on biofilm formation by S. enterica was evaluated by using two recently isolated strains of Salmonella serotypes Enteritidis and Newport. Although supplementing the growth medium with a low concentration (0.5 to 2%) of sodium chloride (NaCl) slightly enhanced biofilm formation for the strain S. enterica serovar Enteritidis 110, it sharply reduced or abolished biofilm formation by the strain S. enterica serovar Newport 193. This differential effect of salinity on S. enterica strains of different serotypes was poorly correlated with inhibition of planktonic growth but strongly correlated with cell motility. Examining genes known to affect biofilm formation showed that the expression of adrA, csgD, and fliC, which encode proteins required for surface adhesion and cell motility, was significantly downregulated with salinity increase in Salmonella Newport 193 but not in Salmonella Enteritidis 110. Therefore, it is plausible that the differential effect of salinity on biofilm formation by Salmonella Enteritidis 110 and Salmonella Newport 193 resulted from the differential regulation to genes required for cell adherence and motility.},
}
@article {pmid31894064,
year = {2019},
author = {Mirza, R and Azeem, M and Qaisar, U},
title = {Influence of Peganum harmala peptides on the transcriptional activity of biofilm related genes in sensitive and resistant strains of Pseudomonas aeruginosa and Staphylococcus aureus.},
journal = {Pakistan journal of pharmaceutical sciences},
volume = {32},
number = {5(Supplementary)},
pages = {2341-2345},
pmid = {31894064},
issn = {1011-601X},
abstract = {Microbial biofilms have gathered interest in recent years as they have become the major cause of nosocomial infections. The abuse and misuse of antibiotics have created a selective pressure that results in widespread formation of resistant bacterial strains and a need to devise novel plant based antimicrobials. In this study, antimicrobial peptides were isolated from Peganum harmala and their effect was examined on biofilm related colonization genes of Pseudomonas aeruginosa and Staphylococcus aureus isolated from burn and surgical wounds. Results showed that in P. aeruginosa isolated from burn wound, the expression of flagellar gene (flgK), pilin gene (pilA) and fimbriae gene (cupA1) was significantly down-regulated indicating that Peganum harmala antimicrobial peptides (PhAMP) damage locomotors of planktonic cells by affecting the gene expression while in resistant biofilm cells, the expression of flgK, cupA1 and polysaccharide synthesis gene (pslA) was enhanced in the presence of PhAMP. In P. aeruginosa isolated from surgical wounds which was more sensitive; the expression of flgK, pilA, cupA1 and pslA was significantly down-regulated in biofilms and planktonic cells in the presence of PhAMP thus disrupting locomotors of planktonic as well as biofilm cells. In S. aureus isolated from burn wounds; the expression of capsular polysaccharide synthesis gene (CPS5) and inter cellular adhesion gene (icaA) was significantly up-regulated in biofilms as well as in planktonic cells in response to PhAMP stress showing resistance mechanism. Thus these genes can be used as efficient resistance markers for bacterial pathogens against antimicrobial agents.},
}
@article {pmid31893017,
year = {2020},
author = {Dubar, M and Zaffino, ML and Remen, T and Thilly, N and Cunat, L and Machouart, MC and Bisson, C},
title = {Protozoans in subgingival biofilm: clinical and bacterial associated factors and impact of scaling and root planing treatment.},
journal = {Journal of oral microbiology},
volume = {12},
number = {1},
pages = {1693222},
doi = {10.1080/20002297.2019.1693222},
pmid = {31893017},
issn = {2000-2297},
abstract = {Objective: In patients with periodontitis, identification of protozoans and evaluation of some bacteria and clinical parameters associated and assessment of scaling and root planing (SRP) impact on their detection. Methods: Before and after SRP, subgingival microbiota was collected in two pathological and one healthy site from 30 periodontitis patients. One healthy site from 30 control patients was also sampled. The usual clinical periodontal parameters were recorded; microbial detection was determined by PCR hybridization system for bacteria and qPCR for protozoans. Results: In periodontitis group, Trichomonas tenax and two subtypes of Entamoeba gingivalis (ST1 and a variant ST2) were detected in respectively 33.3%, 70% and 18.3% of pathological samples, and in 6.7%, 10% and 3.3% healthy samples. In control group, ST1 alone was found in 3.3% of individuals. ST1 was associated with Gingival Index, Clinical Attachment Level (p ≤ 0.03) and with the total bacterial count (p = 0.02). T. tenax alone was associated with P. gingivalis, T. denticola and E. nodatum (p ≤ 0,02). After therapy, only T. tenax detection decreased significantly (p = 0.004) and no association between the protozoan elimination and improvement of pathological sites was found. Conclusions: Protozoans were associated with some clinical parameters and/or periodontopathogens in patients with periodontitis.},
}
@article {pmid31892683,
year = {2019},
author = {Andonissamy, L and Karthigeyan, S and Ali, SA and Felix, JW},
title = {Effect of Chemical Denture Disinfectants and Tree Extracts on Biofilm-forming Staphylococcus aureus and Viridans Streptococcus Species Isolated from Complete Denture.},
journal = {The journal of contemporary dental practice},
volume = {20},
number = {11},
pages = {1307-1314},
pmid = {31892683},
issn = {1526-3711},
abstract = {AIMS: The present study aims at recording the antibacterial efficacy of various disinfectants used at different time periods against Staphylococcus aureus and viridans streptococcal species of bacteria isolated from complete dentures.<br><br>MATERIALS AND METHODS: Fifty complete denture patients were selected for the study and swabs were collected from their complete denture surfaces. The isolated bacteria were subjected to six experimental groups which includes four groups of chemical denture disinfectants and two tree extracts groups. Isolation of the bacteria S. aureus and viridians streptococcal species was done by means of selective media and confirmed by means of biochemical tests. The bacteria were subjected to biofilm assays. The biofilm-forming bacteria with optical density (O.D.) values of more than 1.5 were selected for the study. About 150 acrylic specimens were fabricated and were contaminated by the 2 isolated bacteria mentioned above. The contaminated samples were disinfected by immersion for 10, 20, and 30 minutes in six disinfectants, namely: (1) 1% sodium hypochlorite, (2) 2% chlorhexidine, (3) 2% glutaraldehyde, (4) 3.8% sodium perborate, (5) 2% aalam extract, and (6) 2% neem extract.<br><br>RESULTS: ANOVA test was performed for both S. aureus and viridans streptococcal species with regard to various synthetic and tree extracts as well as time duration of disinfection. F values for disinfection vs S. aureus is 205.4 (p < 0.001) and the relevant Scheffe post hoc test values is in the following order: 3 < 1, 4 < 6, 2 < 5. F values for disinfection vs viridans streptococcal species is 364.7 (p < 0.001) and the relevant Scheffe post hoc test values is in the following order: 3 < 4 < 1, 6, 2 < 5.<br><br>CONCLUSION: For biofilm-forming S. aureus, 2% glutaraldehyde showed best antibacterial efficacy which was followed by 1% sodium hypochlorite and 3.8% sodium perborate. When it comes to biofilm-forming viridans streptococcal species, 2% glutaraldehyde showed best antibacterial efficacy. Next to 2% glutaraldehyde, 3.8% sodium perborate exhibited good disinfection potential.<br><br>CLINICAL SIGNIFICANCE: Complete denture patients have a plethora of microorganisms habitating their complete dentures. Some bacteria are capable of causing systemic illness such as aspiration pneumonia and endocarditis. Hence, constant removal and disinfection of biofilms from the denture surface is vital to the local and systemic wellness of the patient. The most common bacteria capable of causing pneumonia and endocarditis that are isolated from complete dentures include S. aureus and viridans streptococcal species. The present study evaluates antibacterial efficacy of different disinfection agents especially against these biofilm-forming bacteria for different time periods. How to cite this article: Andonissamy L, Karthigeyan S, Ali SA, et al. Effect of Chemical Denture Disinfectants and Tree Extracts on Biofilm-forming Staphylococcus aureus and Viridans Streptococcus Species Isolated from Complete Denture. J Contemp Dent Pract 2019;20(11):1307-1314.},
}
@article {pmid31891540,
year = {2020},
author = {Yener, SB and Özsoy, ÖP},
title = {Quantitative analysis of biofilm formation on labial and lingual bracket surfaces.},
journal = {The Angle orthodontist},
volume = {90},
number = {1},
pages = {100-108},
doi = {10.2319/110818-803.1},
pmid = {31891540},
issn = {1945-7103},
abstract = {OBJECTIVES: To evaluate and compare the biofilm formation between labial and lingual orthodontic brackets.<br><br>MATERIALS AND METHODS: Twenty patients with a mean age of 24 ± 8.8 who had received labial or lingual orthodontic treatment were enrolled in the study. Biofilm formation on 80 brackets was analyzed quantitatively with the Rutherford backscattering detection method. Five micrographs were obtained per bracket with views from the vestibule/lingual, mesial, distal, gingival, and occlusal aspects. Quantitative analysis was carried out with surface analysis software (ImageJ 1.48). Data were analyzed by Mann-Whitney U and Kruskal-Wallis tests (α = 0.05).<br><br>RESULTS: Total biofilm formation was 41.56% (min 29.43% to max 48.76%) on lingual brackets and 26.52% (min 21.61% to max 32.71%) on labial brackets. Differences between the two groups were found to be significant. No difference was observed in intraoral location. The biofilm accumulation was mostly located on gingival, mesial, and distal surfaces for both groups.<br><br>CONCLUSIONS: The biofilm accumulation on lingual orthodontic therapy was found to be more than labial orthodontic therapy.},
}
@article {pmid31891070,
year = {2019},
author = {Lara, HH and Black, DM and Moon, C and Orr, E and Lopez, P and Alvarez, MM and Baghdasarian, G and Lopez-Ribot, J and Whetten, RL},
title = {Activating a Silver Lipoate Nanocluster with a Penicillin Backbone Induces a Synergistic Effect against S. aureus Biofilm.},
journal = {ACS omega},
volume = {4},
number = {26},
pages = {21914-21920},
doi = {10.1021/acsomega.9b02908},
pmid = {31891070},
issn = {2470-1343},
abstract = {Many antibiotic resistances to penicillin have been reported, making them obsolete against multiresistant bacteria. Because penicillins act by inhibiting cell wall production while silver particles disrupt the cell wall directly, a synergetic effect is anticipated when both modes of action are incorporated into a chimera cluster. To test this hypothesis, the lipoate ligands (LA) of a silver cluster (Ag29) of known composition (Ag29LA12)[3-] were covalently conjugated to 6-aminopenicillanic acid, a molecule with a β-lactam backbone. Indeed, the partially conjugated cluster inhibited an Staphylococcus aureus biofilm, in a dose-response manner, with a half-maximal inhibitory concentration IC50 of 2.3 μM, an improvement over 60 times relative to the unconjugated cluster (IC50 = 140 μM). An enhancement of several orders of magnitude over 6-APA alone (unconjugated) was calculated (IC50 = 10 000 μM). Cell wall damage is documented via scanning electron microscopy. A synergistic effect of the conjugate was calculated by the combination index method described by Chou-Talalay. This hybrid nanoantibiotic opens a new front against multidrug-resistant pathogens.},
}
@article {pmid31890796,
year = {2020},
author = {De Jesus, R and Dedeles, G},
title = {Data on quantitation of Bacillus cereus sensu lato biofilms by microtiter plate biofilm formation assay.},
journal = {Data in brief},
volume = {28},
number = {},
pages = {104951},
doi = {10.1016/j.dib.2019.104951},
pmid = {31890796},
issn = {2352-3409},
abstract = {The microtiter plate biofilm formation assay is a method for the study of early biofilm formation on abiotic surfaces. It is a colorimetric technique that uses dyes, such as crystal violet, to stain attached biofilms and to quantify by using an absorbance microtiter plate reader. In this data, we evaluated the ability of 12 Bacillus cereus sensu lato isolated from soil and milk powder samples for their production of biofilms after a total of 48 hr incubation period in the 96-well microtiter plate. The biofilm production was induced by initially exposing them in diluted tryptic soy broth at its first 24 hr and then replacing with freshly prepared double strength broth for the next incubation period at 30 °C. The optical densities of the bacterial growth in the wells were read at the absorbance wavelength of 630 nm while the stained biofilms that solubilized in absolute ethanol were read at 570 nm. The biofilm measurements were calculated and the degree of biofilm production of each isolate was classified according to biofilm formation categories adapted from previous researchers. Therefore, the assay concluded the negative impact of B. cereus group by ability to form biofilms on abiotic surfaces, such as food contact surfaces in food production industries and the wide application of the current methods in research and industrial fields.},
}
@article {pmid31890013,
year = {2019},
author = {Nirwati, H and Sinanjung, K and Fahrunissa, F and Wijaya, F and Napitupulu, S and Hati, VP and Hakim, MS and Meliala, A and Aman, AT and Nuryastuti, T},
title = {Biofilm formation and antibiotic resistance of Klebsiella pneumoniae isolated from clinical samples in a tertiary care hospital, Klaten, Indonesia.},
journal = {BMC proceedings},
volume = {13},
number = {Suppl 11},
pages = {20},
doi = {10.1186/s12919-019-0176-7},
pmid = {31890013},
issn = {1753-6561},
abstract = {Background: Klebsiella pneumoniae (K. pneumoniae) is a common cause of health-care associated infections (HAIs) and has high levels of antibiotic resistance. These bacteria are well-known for their ability to produce biofilm. The purpose of this study was to identify the antibiotic resistance pattern and biofilm-producing capacity of K. pneumoniae isolated from clinical samples in a tertiary care hospital in Klaten, Indonesia.<br><br>Methods: K. pneumoniae was isolated from inpatients in Soeradji Tirtonegoro Hospital Klaten from June 2017 to May 2018. Identification of K. pneumoniae isolate was done by analyzing colony morphology, microscopic examination, and by performing biochemical testing. Testing of antibiotics susceptibility and biofilm-producing capacity used the Kirby-Bauer disk diffusion method and adherence quantitative assays, respectively.<br><br>Results: A total of 167 (17.36%) K. pneumoniae isolates were isolated from 962 total clinical bacterial isolates during the study. Most of them were collected from patients aged more than 60 years old and were mainly obtained from respiratory specimens (51.50%). Most of K. pneumoniae isolates were extensively resistant to antibiotics. A more favorable profile was found only towards meropenem, amikacin, and piperacillin-tazobactam, showing 1.20%; 4.79% and 10.53% of resistance, respectively. The overall proportion of multidrug-resistant K. pneumoniae isolates was 54.49%. In addition, 148 (85.63%) isolates were biofilm producers, with 45 (26.95%) isolates as strong, 48 (28.74%) isolates as moderate, and 50 (29.94%) isolates as weak biofilm producers.<br><br>Conclusion: Most of the K. pneumoniae isolates demonstrated resistance to a wide range of antibiotics and are biofilm producers.},
}
@article {pmid31890012,
year = {2019},
author = {Krislee, A and Fadly, C and Nugrahaningsih, DAA and Nuryastuti, T and Nitbani, FO and Jumina, and Sholikhah, EN},
title = {The 1-monolaurin inhibit growth and eradicate the biofilm formed by clinical isolates of Staphylococcus epidermidis.},
journal = {BMC proceedings},
volume = {13},
number = {Suppl 11},
pages = {19},
doi = {10.1186/s12919-019-0174-9},
pmid = {31890012},
issn = {1753-6561},
abstract = {Background: Biofilm is one of the causes of antibiotic resistance. One of the biofilm-producing bacteria is Staphylococcus epidermidis which has been proven to infect long-term users of urinary catheters and implant devices. The 1-monolaurin compound has been known to have an antimicrobial effect. However, its effect on clinical isolates of S. epidermidis in producing biofilm has not been established. This study was conducted to investigate the effect of 1-monolaurin towards biofilm forming clinical isolates of S. epidermidis.<br><br>Methods: The experiment used micro broth dilution technique which consists of test group (1-monolaurin), positive control group (rifampicin), solvent group, negative control group (clinical isolate of S. epidermidis), and media group (TSB media). The Minimal Inhibition Concentration (MIC) was determined by incubating bacteria added with 1-monolaurin (1000-1953 μg/mL) or rifampicin (250-0,488 μg/mL) for 24 h. The MIC was determined visually. After that, the incubated bacteria was cultured in TSA media to determine Minimal Bactericidal Concentration (MBC). The assessment of Biofilm inhibitory Concentration (BIC) and Biofilm Eradication Concentration (BEC) was conducted with the same way, the difference was BIC intervened directly with compound meanwhile BEC was incubated for 24 h in 37 °C before the intervention. Then, the specimen was reincubated to grow biofilm at the microplate, washed with PBS and stained with 1% of crystal violet. The optical density (OD) was measured at a wavelength of 595 nm. The percentage of BIC and BEC then were calculated, continued to probit analysis regression to determine the BIC50, BIC80, BEC50, and BEC80.<br><br>Results: The MIC dan MBC of 1-monolaurin and rifampicin were > 1000 μg/mL, > 1000 μg/mL, ≤0.488 μg/mL, and 1.953 μg/mL respectively. BIC50 and BIC80 of 1-monolaurin and rifampicin were 26.669 μg/mL, 168.688 μg/mL, 0.079 μg/mL, and 0.974 μg/mL respectively. The BEC50 and BEC80 of 1-monolaurin and rifampicin were 322.504 μg/mL, 1338.681 μg/mL, 5.547 μg/mL, dan 17.910 μg/mL respectively.<br><br>Conclusion: The 1-monolaurin can inhibit growth and eradicate the biofilm formed by clinical isolates of S. epidermidis, however, it has neither inhibit nor kill planktonic cells of S. epidermidis.},
}
@article {pmid31889815,
year = {2020},
author = {Jasmine, S and A, T and Janarthanan, K and Krishnamoorthy, R and Alshatwi, AA},
title = {Antimicrobial and antibiofilm potential of injectable platelet rich fibrin-a second-generation platelet concentrate-against biofilm producing oral staphylococcus isolates.},
journal = {Saudi journal of biological sciences},
volume = {27},
number = {1},
pages = {41-46},
doi = {10.1016/j.sjbs.2019.04.012},
pmid = {31889815},
issn = {1319-562X},
abstract = {Injectable Platelet rich fibrin (i-PRF) is a platelet concentrate that has been extensively used for multiple medical purposes and is a valuable adjunct for the regeneration of damaged tissues in surgical procedures. The enriched bioactive substances in i-PRF are responsible for speeding the wound healing process. Infection of biofilm producing bacteria in surgical wounds is becoming a serious threat. Research in this field is focused on new strategies to fight infections and to reduce the healing time. The present study was aimed to evaluate the in vitro antimicrobial and antibiofilm effects of i-PRF against oral pathogenic biofilm producing staphylococcus bacteria isolated from patient with dental and oral abscess. The antibacterial activity of i-PRF, was determined through broth microdilution as minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). i-PRF exhibited bactericidal activity against both non biofilm and biofilm producing bacteria. i-PRF could be potential antimicrobial peptide used to combat postoperative infections caused by biofilm producing staphylococcus.},
}
@article {pmid31888471,
year = {2019},
author = {Slade, EA and Thorn, RMS and Young, A and Reynolds, DM},
title = {An in vitro collagen perfusion wound biofilm model; with applications for antimicrobial studies and microbial metabolomics.},
journal = {BMC microbiology},
volume = {19},
number = {1},
pages = {310},
doi = {10.1186/s12866-019-1682-5},
pmid = {31888471},
issn = {1471-2180},
abstract = {BACKGROUND: The majority of in vitro studies of medically relevant biofilms involve the development of biofilm on an inanimate solid surface. However, infection in vivo consists of biofilm growth on, or suspended within, the semi-solid matrix of the tissue, whereby current models do not effectively simulate the nature of the in vivo environment. This paper describes development of an in vitro method for culturing wound associated microorganisms in a system that combines a semi-solid collagen gel matrix with continuous flow of simulated wound fluid. This enables culture of wound associated reproducible steady state biofilms under conditions that more closely simulate the dynamic wound environment. To demonstrate the use of this model the antimicrobial kinetics of ceftazidime, against both mature and developing Pseudomonas aeruginosa biofilms, was assessed. In addition, we have shown the potential application of this model system for investigating microbial metabolomics by employing selected ion flow tube mass spectrometry (SIFT-MS) to monitor ammonia and hydrogen cyanide production by Pseudomonas aeruginosa biofilms in real-time.<br><br>RESULTS: The collagen wound biofilm model facilitates growth of steady-state reproducible Pseudomonas aeruginosa biofilms under wound like conditions. A maximum biofilm density of 1010 cfu slide- 1 was achieved by 30 h of continuous culture and maintained throughout the remainder of the experiment. Treatment with ceftazidime at a clinically relevant dose resulted in a 1.2-1.6 log reduction in biofilm density at 72 h compared to untreated controls. Treatment resulted in loss of complex biofilm architecture and morphological changes to bacterial cells, visualised using confocal microscopy. When monitoring the biofilms using SIFT-MS, ammonia and hydrogen cyanide levels peaked at 12 h at 2273 ppb (±826.4) and 138 ppb (±49.1) respectively and were detectable throughout experimentation.<br><br>CONCLUSIONS: The collagen wound biofilm model has been developed to facilitate growth of reproducible biofilms under wound-like conditions. We have successfully used this method to: (1) evaluate antimicrobial efficacy and kinetics, clearly demonstrating the development of antimicrobial tolerance in biofilm cultures; (2) characterise volatile metabolite production by P. aeruginosa biofilms, demonstrating the potential use of this method in metabolomics studies.},
}
@article {pmid31888149,
year = {2019},
author = {Meroni, G and Soares Filipe, JF and Drago, L and Martino, PA},
title = {Investigation on Antibiotic-Resistance, Biofilm Formation and Virulence Factors in Multi Drug Resistant and Non Multi Drug Resistant Staphylococcus pseudintermedius.},
journal = {Microorganisms},
volume = {7},
number = {12},
pages = {},
doi = {10.3390/microorganisms7120702},
pmid = {31888149},
issn = {2076-2607},
abstract = {Staphylococcus pseudintermedius is a commensal bacterium frequently isolated from canine skin and recognized as a zoonotic agent especially for dog-owners. This study focused on (a) the antibiotic-resistance phenotypes; (b) the ability to produce biofilm (slime); and (c) the dissemination of virulence factors in S. pseudintermedius strains. Seventy-three S. pseudintermedius strains were screened for antibiotic-resistance against 22 different molecules by means of Kirby-Bauer assay. The ability to produce biofilm was investigated using the microtiter plate assay (MtP) and the amplification of icaA and icaD genes. Virulence factors such as cytotoxins (lukI), enterotoxins (seC), and exfoliative toxins (siet, expA, and expB) were evaluated. The antibiotic-resistance profiles revealed 42/73 (57%) multi-drug resistant (MDR) strains and 31/73 (43%) not-MDR. All the MDR strains and 8/31 (27%) of not-MDR resulted in biofilm producers. Leukotoxin LukI was found in 70/73 (96%) of the isolates. Moreover, the enterotoxin gene seC was detected in 47/73 (64%) of the strains. All the isolates carried the siet gene, whereas expA and expB were found in 3/73 (4%) and 5/73 (7%), respectively. In conclusion, S. pseudintermedius should be considered a potential zoonotic and human agent able to carry different virulence determinants and capable of producing biofilm which facilitates horizontal gene transfer.},
}
@article {pmid31887894,
year = {2020},
author = {Muthuchamy, M and Govindan, R and Shine, K and Thangasamy, V and Alharbi, NS and Thillaichidambaram, M and Khaled, JM and Wen, JL and Alanzi, KF},
title = {Anti-biofilm investigation of graphene/chitosan nanocomposites against biofilm producing P. aeruginosa and K. pneumoniae.},
journal = {Carbohydrate polymers},
volume = {230},
number = {},
pages = {115646},
doi = {10.1016/j.carbpol.2019.115646},
pmid = {31887894},
issn = {1879-1344},
abstract = {In this study graphene/chitosan nanoparticles (GR/CS NCs) were developed. The homogenous combination of GR and CS was confirmed by FTIR spectroscopy. The combination of CS with GR sheets reduced the XRD intensity of the GR peak in GR/CS NCs, while TEM images revealed the immobile CS coating of GR sheets. Further, the anti-biofilm activity of GR/CS NCs was tested. The tests showed that the formation of biofilm by Pseudomonas aeruginosa and Klebsiella pneumoniae was inhibited at 40□g/mL GR/CS NCs up to 94 and 92 %, respectively. The intracellular and cell surface damage of the bacteria was observed by CLSM and SEM. Also, GR/CS NCs produced a toxic effect of 90 % on Artemia franciscana at 70□g/mL upon 24 h incubation. The recorded properties of the synthesized GR/CS NCs qualify them as potential agents against multi-drug resistant bacteria.},
}
@article {pmid31887516,
year = {2019},
author = {Choi, PM and Li, J and Gao, J and O'Brien, JW and Thomas, KV and Thai, PK and Jiang, G and Mueller, JF},
title = {Considerations for assessing stability of wastewater-based epidemiology biomarkers using biofilm-free and sewer reactor tests.},
journal = {The Science of the total environment},
volume = {709},
number = {},
pages = {136228},
doi = {10.1016/j.scitotenv.2019.136228},
pmid = {31887516},
issn = {1879-1026},
abstract = {Wastewater-based epidemiology is an increasingly popular method for analysing drugs or metabolites excreted by populations. The in-sewer transformation of biomarkers is important but often receives little consideration in published studies. Many studies publish stability under biofilm-free conditions only, which do not represent actual sewer conditions. This study aims to fill a gap in the field by comparing the wastewater stability of 33 licit drug and pharmaceutical biomarkers in biofilm-free (BFF) conditions to stability in sewer biofilm reactors. All but one biomarker was stable under BFF conditions, whereas most transformed in sewer biofilm reactors. Sewer reactor results tended to overestimate the degradation in pilot and actual sewers, whereas BFF stability had no clear relationship to stability in pilot and actual sewers. Our results provide additional basis for more informed interpretation of biofilm-free and sewer reactor stability results for past and future WBE studies.},
}
@article {pmid31886204,
year = {2019},
author = {Minami, M and Takase, H and Nakamura, M and Makino, T},
title = {Effect of Lonicera caerulea var. emphyllocalyx Fruit on Biofilm Formed by Porphyromonas gingivalis.},
journal = {BioMed research international},
volume = {2019},
number = {},
pages = {3547858},
doi = {10.1155/2019/3547858},
pmid = {31886204},
issn = {2314-6141},
abstract = {Porphyromonas gingivalis is an important pathogenic anaerobic bacterium that causes aspiration pneumonia. This bacterium frequently forms biofilms in the oral cavity and in respiratory tract-associated medical devices. Bacterial colonization that occurs in association with this biofilm formation is the main reason for incurable aspiration pneumonia. The Lonicera caerulea var. emphyllocalyx (LCE) fruit has been used in folk medicine in Hokkaido, the northern part of Japan. The aim of this study was to elucidate one of the antimicrobial mechanisms of LCE methanol extract (LCEE)-the inhibitory effect of LCEE on biofilm formation by P. gingivalis. Our results show that LCEE significantly reduced biofilm formation by three different P. gingivalis isolates in a concentration- and time-dependent manner that were quantified by the adsorption of safranin red. When LCEE was added to biofilms already formed by P. gingivalis, LCEE did not degrade the biofilm. However, treatment with LCEE significantly promoted the removal of existing biofilm by vibration compared to that of control. We also confirmed biofilm formation in LCEE-treated P. gingivalis in tracheal tubes using scanning electron microscopic (SEM) analysis. Cyanidin 3-O-glucoside (C3G), one of the components of LCE, also inhibited the formation of biofilm by P. gingivalis in a concentration-dependent manner. Our results reveal that LCEE may be an effective antibacterial substance for P. gingivalis-induced aspiration pneumonia because of its role in the suppression of bacterial biofilm formation in the oral cavity.},
}
@article {pmid31885632,
year = {2019},
author = {Adusei, EBA and Adosraku, RK and Oppong-Kyekyeku, J and Amengor, CDK and Jibira, Y},
title = {Resistance Modulation Action, Time-Kill Kinetics Assay, and Inhibition of Biofilm Formation Effects of Plumbagin from Plumbago zeylanica Linn.},
journal = {Journal of tropical medicine},
volume = {2019},
number = {},
pages = {1250645},
doi = {10.1155/2019/1250645},
pmid = {31885632},
issn = {1687-9686},
abstract = {Antimicrobial resistance (AMR) is a threat to the prevention and treatment of the increasing range of infectious diseases. There is therefore the need for renewed efforts into antimicrobial discovery and development to combat the menace. The antimicrobial activity of plumbagin isolated from roots of Plumbago zeylanica against selected organisms was evaluated for resistance modulation antimicrobial assay, time-kill kinetics assay, and inhibition of biofilm formation. The minimum inhibitory concentrations (MICs) of plumbagin and standard drugs were determined via the broth microdilution method to be 0.5 to 8 μg/mL and 0.25-128 μg/mL, respectively. In the resistance modulation study, MICs of the standard drugs were redetermined in the presence of subinhibitory concentration of plumbagin (4 μg/mL), and plumbagin was found to either potentiate or reduce the activities of these standard drugs with the highest potentiation recorded up to 12-folds for ketoconazole against Candida albicans. Plumbagin was found to be bacteriostatic and fungistatic from the time-kill kinetics study. Plumbagin demonstrated strong inhibition of biofilm formation activity at concentrations of 128, 64, and 32 μg/mL against the test microorganisms compared with ciprofloxacin. Plumbagin has been proved through this study to be a suitable lead compound in antimicrobial resistance drug development.},
}
@article {pmid31885354,
year = {2019},
author = {Taghizadeh, L and Karimi, A and Presterl, E and Heitzinger, C},
title = {Bayesian inversion for a biofilm model including quorum sensing.},
journal = {Computers in biology and medicine},
volume = {117},
number = {},
pages = {103582},
doi = {10.1016/j.compbiomed.2019.103582},
pmid = {31885354},
issn = {1879-0534},
abstract = {We propose a mathematical model based on a system of partial differential equations (PDEs) for biofilms. This model describes the time evolution of growth and degradation of biofilms which depend on environmental factors. The proposed model also includes quorum sensing (QS) and describes the cooperation among bacteria when they need to resist against external factors such as antibiotics. The applications include biofilms on teeth and medical implants, in drinking water, cooling water towers, food processing, oil recovery, paper manufacturing, and on ship hulls. We state existence and uniqueness of solutions of the proposed model and implement the mathematical model to discuss numerical simulations of biofilm growth and cooperation. We also determine the unknown parameters of the presented biofilm model by solving the corresponding inverse problem. To this end, we propose Bayesian inversion techniques and the delayed-rejection adaptive-Metropolis (DRAM) algorithm for the simultaneous extraction of multiple parameters from the measurements. These quantities cannot be determined directly from the experiments or from the computational model. Furthermore, we evaluate the presented model by comparing the simulations using the estimated parameter values with the measurement data. The results illustrate a very good agreement between the simulations and the measurements.},
}
@article {pmid31885074,
year = {2019},
author = {Taşkan, B and Hasar, H and Lee, CH},
title = {Effective biofilm control in a membrane biofilm reactor using a quenching bacterium (Rhodococcus sp. BH4).},
journal = {Biotechnology and bioengineering},
volume = {},
number = {},
pages = {},
doi = {10.1002/bit.27259},
pmid = {31885074},
issn = {1097-0290},
abstract = {The biofilm thickness in membrane biofilm reactors (MBfRs) is an important factor affecting system performance because excessive biofilm formation on the membrane surface inhibits gas diffusion to the interior of the biofilm, resulting in a significant reduction in the performance of contaminant removal. This study provides innovative insights into the control of biofilm thickness in the O2 based MBfRs by using quorum quenching (QQ) method. The study was carried out in the MBfRs operated at different gas pressures and hydraulic retention times using QQ beads containing Rhodococcus sp. BH4 at different amounts. The highest performance was observed in the reactors operated with 0.21 ml QQ bead/cm2 membrane surface area, 12 HRT and 1.40 atm. In this period, the performance increase in COD removal was 25%, while the biofilm thickness on the membrane surface was determined as 250 μm. Moreover, acetate and equivalent oxygen flux results reached 6080 and 10640 mg/m2 .d maximum values, respectively. The extracellular polymeric substances (EPS) of the biofilm decreased significantly with the increase of gas pressure and QQ beads amount. PCR-DGGE results showed that the microbial community in the MBfR system changed depending on operating conditions and bead amount. The results showed that the QQ method was an effective method to control the biofilm thickness in MBfR, and provides insights for future research. This article is protected by copyright. All rights reserved.},
}
@article {pmid31882963,
year = {2019},
author = {Cambronel, M and Tortuel, D and Biaggini, K and Maillot, O and Taupin, L and Réhel, K and Rincé, I and Muller, C and Hardouin, J and Feuilloley, M and Rodrigues, S and Connil, N},
title = {Epinephrine affects motility, and increases adhesion, biofilm and virulence of Pseudomonas aeruginosa H103.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {20203},
doi = {10.1038/s41598-019-56666-7},
pmid = {31882963},
issn = {2045-2322},
abstract = {Microbial endocrinology has demonstrated for more than two decades, that eukaryotic substances (hormones, neurotransmitters, molecules of the immune system) can modulate the physiological behavior of bacteria. Among them, the hormones/neurotransmitters, epinephrine (Epi) and norepinephrine (NE), released in case of stress, physical effort or used in medical treatment, were shown to be able to modify biofilm formation in various bacterial species. In the present study, we have evaluated the effect of Epi on motility, adhesion, biofilm formation and virulence of Pseudomonas aeruginosa, a bacterium linked to many hospital-acquired infections, and responsible for chronic infection in immunocompromised patients including persons suffering from cystic fibrosis. The results showed that Epi increased adhesion and biofilm formation of P. aeruginosa, as well as its virulence towards the Galleria mellonella larvae in vivo model. Deciphering the sensor of this molecule in P. aeruginosa and the molecular mechanisms involved may help to find new strategies of treatment to fight against this bacterium.},
}
@article {pmid31882881,
year = {2019},
author = {Shi, L and Wu, Y and Yang, C and Ma, Y and Zhang, QZ and Huang, W and Zhu, XY and Yan, YJ and Wang, JX and Zhu, T and Qu, D and Zheng, CQ and Zhao, KQ},
title = {Effect of nicotine on Staphylococcus aureus biofilm formation and virulence factors.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {20243},
doi = {10.1038/s41598-019-56627-0},
pmid = {31882881},
issn = {2045-2322},
abstract = {Staphylococcus aureus is a common pathogen in chronic rhinosinusitis (CRS) patients, the pathogenesis of which involves the ability to form biofilms and produce various virulence factors. Tobacco smoke, another risk factor of CRS, facilitates S. aureus biofilm formation; however, the mechanisms involved are unclear. Here, we studied the effect of nicotine on S. aureus biofilm formation and the expression of virulence-related genes. S. aureus strains isolated from CRS patients and a USA300 strain were treated with nicotine or were untreated (control). Nicotine-treated S. aureus strains showed dose-dependent increases in biofilm formation, lower virulence, enhanced initial attachment, increased extracellular DNA release, and a higher autolysis rate, involving dysregulation of the accessory gene regulator (Agr) quorum-sensing system. Consequently, the expression of autolysis-related genes lytN and atlA, and the percentage of dead cells in biofilms was increased. However, the expression of virulence-related genes, including hla, hlb, pvl, nuc, ssp, spa, sigB, coa, and crtN was downregulated and there was reduced bacterial invasion of A549 human alveolar epithelial cells. The results of this study indicate that nicotine treatment enhances S. aureus biofilm formation by promoting initial attachment and extracellular DNA release but inhibits the virulence of this bacterium.},
}
@article {pmid31882539,
year = {2019},
author = {Samanta, S and Biswas, P and Banerjee, A and Bose, A and Siddiqui, N and Nambi, S and Saini, DK and Visweswariah, SS},
title = {A universal stress protein in Mycobacterium smegmatis sequesters the cAMP-regulated lysine acyltransferase and is essential for biofilm formation.},
journal = {The Journal of biological chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1074/jbc.RA119.011373},
pmid = {31882539},
issn = {1083-351X},
abstract = {Universal stress proteins (USPs) are present in many bacteria and their expression is enhanced under various environmental stresses. We have previously identified a USP in Mycobacterium smegmatis that is a product of the msmeg_4207 gene and is a substrate for a cAMP-regulated protein lysine acyltransferase, KATms (MSMEG_5458). Here, we explored the role of this USP (USP4207) in M. smegmatis, finding that its gene is present in an operon that also contains genes predicted to encode a putative tripartite tricarboxylate transporter (TTT). Transcription of the TTT-usp4207 operon was induced in the presence of citrate and tartrate, perhaps by the activity of a divergent histidine kinase-response regulator gene pair. A usp4207 -deleted strain had rough colony morphology and reduced biofilm formation compared with the WT strain; however, both normal colony morphology and biofilm formation were restored in a Δusp4207 Δkatms strain. We identified several proteins whose acetylation was lost in the Δkatms strain, and whose transcript levels increased in M. smegmatis biofilms along with that of USP4207, suggesting that USP4207 insulates KATms from its other substrates in the cell. We propose that USP4207 sequesters KATms from diverse substrates whose activities are down-regulated by acylation but which are required for biofilm formation, thus providing a defined role for this USP in mycobacterial physiology and stress responses.},
}
@article {pmid31880890,
year = {2019},
author = {Olender, A and Bogut, A and Magryś, A and Tabarkiewicz, J},
title = {Cytokine Levels in the In Vitro Response of T Cells to Planktonic and Biofilm Corynebacterium amycolatum.},
journal = {Polish journal of microbiology},
volume = {68},
number = {4},
pages = {457-464},
doi = {10.33073/pjm-2019-045},
pmid = {31880890},
issn = {2544-4646},
abstract = {Unravelling of the interplay between the immune system and non-diphtheria corynebacteria would contribute to understanding their increasing role as medically important microorganisms. We aimed at the analysis of pro- (TNF, IL-1β, IL-6, IL-8, and IL-12p70) and anti-inflammatory (IL-10) cytokines produced by Jurkat T cells in response to planktonic and biofilm Corynebacterium amycolatum. Two reference strains: C. amycolatum ATCC 700207 (R-CA), Staphylococcus aureus ATCC 25923 (R-SA), and ten clinical strains of C. amycolatum (C-CA) were used in the study. Jurkat T cells were stimulated in vitro by the planktonic-conditioned medium (PCM) and biofilm-conditioned medium (BCM) derived from the relevant cultures of the strains tested. The cytokine concentrations were determined in the cell culture supernatants using the flow cytometry. The levels of the cytokines analyzed were lower after stimulation with the BCM when compared to the PCM derived from the cultures of C-CA; statistical significance (p < 0.05) was observed for IL-1β, IL-12 p70, and IL-10. Similarly, planktonic R-CA and R-SA stimulated a higher cytokine production than their biofilm counterparts. The highest levels of pro-inflammatory IL-8, IL-1β, and IL-12p70 were observed after stimulation with planktonic R-SA whereas the strongest stimulation of anti-inflammatory IL-10 was noted for the BCM derived from the mixed culture of both reference species. Our results are indicative of weaker immunostimulatory properties of the biofilm C. amycolatum compared to its planktonic form. It may play a role in the persistence of biofilm-related infections. The extent of the cytokine response can be dependent on the inherent virulence of the infecting microorganism.<br><br>Unravelling of the interplay between the immune system and non-diphtheria corynebacteria would contribute to understanding their increasing role as medically important microorganisms. We aimed at the analysis of pro- (TNF, IL-1β, IL-6, IL-8, and IL-12p70) and anti-inflammatory (IL-10) cytokines produced by Jurkat T cells in response to planktonic and biofilm Corynebacterium amycolatum. Two reference strains: C. amycolatum ATCC 700207 (R-CA), Staphylococcus aureus ATCC 25923 (R-SA), and ten clinical strains of C. amycolatum (C-CA) were used in the study. Jurkat T cells were stimulated in vitro by the planktonic-conditioned medium (PCM) and biofilm-conditioned medium (BCM) derived from the relevant cultures of the strains tested. The cytokine concentrations were determined in the cell culture supernatants using the flow cytometry. The levels of the cytokines analyzed were lower after stimulation with the BCM when compared to the PCM derived from the cultures of C-CA; statistical significance (p < 0.05) was observed for IL-1β, IL-12 p70, and IL-10. Similarly, planktonic R-CA and R-SA stimulated a higher cytokine production than their biofilm counterparts. The highest levels of pro-inflammatory IL-8, IL-1β, and IL-12p70 were observed after stimulation with planktonic R-SA whereas the strongest stimulation of anti-inflammatory IL-10 was noted for the BCM derived from the mixed culture of both reference species. Our results are indicative of weaker immunostimulatory properties of the biofilm C. amycolatum compared to its planktonic form. It may play a role in the persistence of biofilm-related infections. The extent of the cytokine response can be dependent on the inherent virulence of the infecting microorganism.},
}
@article {pmid31880259,
year = {2019},
author = {Abdalla, SSI and Katas, H and Azmi, F and Busra, MFM},
title = {Antibacterial and Anti-Biofilm Biosynthesised Silver and Gold Nanoparticles for Medical Applications: Mechanism of action, Toxicity and Current Status.},
journal = {Current drug delivery},
volume = {},
number = {},
pages = {},
doi = {10.2174/1567201817666191227094334},
pmid = {31880259},
issn = {1875-5704},
abstract = {Fast progress in nanoscience and nanotechnology has contributed to the way in which people diagnose, combat, and overcome various diseases differently from the conventional methods. Metal nanoparticles, mainly silver and gold nanoparticles (AgNPs and AuNPs, respectively), are currently developed for many applications in the medical and pharmaceutical area including as antibacterial, anti-biofilm as well as anti-leshmanial agents, drug delivery systems, diagnostics tools, as well as being included in personal care products and cosmetics. In this review, the preparation of AgNPs and AuNPs using different methods is discussed, particularly the green or bio- synthesis method as well as common methods used for their physical and chemical characterization. In addition, the mechanisms of the antimicrobial and anti-biofilm activity of AgNPs and AuNPs are discussed, along with the toxicity of both nanoparticles. The review will provide insight into the potential of biosynthesized AgNPs and AuNPs as antimicrobial nanomaterial agents for future use.},
}
@article {pmid31879573,
year = {2019},
author = {Bekliz, M and Brandani, J and Bourquin, M and Battin, TJ and Peter, H},
title = {Benchmarking protocols for the metagenomic analysis of stream biofilm viromes.},
journal = {PeerJ},
volume = {7},
number = {},
pages = {e8187},
doi = {10.7717/peerj.8187},
pmid = {31879573},
issn = {2167-8359},
abstract = {Viruses drive microbial diversity, function and evolution and influence important biogeochemical cycles in aquatic ecosystems. Despite their relevance, we currently lack an understanding of their potential impacts on stream biofilm structure and function. This is surprising given the critical role of biofilms for stream ecosystem processes. Currently, the study of viruses in stream biofilms is hindered by the lack of an optimized protocol for their extraction, concentration and purification. Here, we evaluate a range of methods to separate viral particles from stream biofilms, and to concentrate and purify them prior to DNA extraction and metagenome sequencing. Based on epifluorescence microscopy counts of viral-like particles (VLP) and DNA yields, we optimize a protocol including treatment with tetrasodium pyrophosphate and ultra-sonication to disintegrate biofilms, tangential-flow filtration to extract and concentrate VLP, followed by ultracentrifugation in a sucrose density gradient to isolate VLP from the biofilm slurry. Viromes derived from biofilms sampled from three different streams were dominated by Siphoviridae, Myoviridae and Podoviridae and provide first insights into the viral diversity of stream biofilms. Our protocol optimization provides an important step towards a better understanding of the ecological role of viruses in stream biofilms.},
}
@article {pmid31878164,
year = {2019},
author = {López, Y and Soto, SM},
title = {The Usefulness of Microalgae Compounds for Preventing Biofilm Infections.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {9},
number = {1},
pages = {},
doi = {10.3390/antibiotics9010009},
pmid = {31878164},
issn = {2079-6382},
abstract = {Biofilms play an important role in infectious diseases. It has been estimated that most medical infections are due to bacterial biofilms, and about 60-70% of nosocomial infections are also caused by the formation of a biofilm. Historically, microalgae are an important source of bioactive compounds, having novel structures and potential biological functions that make them attractive for different industries such as food, animal feed, aquaculture, cosmetics, and pharmaceutical. Several studies have described compounds produced by microalgae and cyanobacteria species with antimicrobial activity. However, studies on the antibiofilm activity of extracts and/or molecules produced by these microorganisms are scarce. Quorum-sensing inhibitor and anti-adherent agents have, among others, been isolated from microalgae and cyanobacteria species. The use of tools such as nanotechnology increase their power of action and can be used for preventing and treating biofilm-related infections.},
}
@article {pmid31877837,
year = {2019},
author = {Kot, B and Sytykiewicz, H and Sprawka, I and Witeska, M},
title = {Effect of trans-Cinnamaldehyde on Methicillin-Resistant Staphylococcus aureus Biofilm Formation: Metabolic Activity Assessment and Analysis of the Biofilm-Associated Genes Expression.},
journal = {International journal of molecular sciences},
volume = {21},
number = {1},
pages = {},
doi = {10.3390/ijms21010102},
pmid = {31877837},
issn = {1422-0067},
abstract = {The effects of trans-cinnamaldehyde (TC) on transcriptional profiles of biofilm-associated genes and the metabolic activity of two methicillin-resistant Staphylococcus aureus (MRSA) strains showing a different degree of adherence to polystyrene, were evaluated. Metabolic activity of S. aureus in biofilm was significantly decreased in the presence of TC at 1/2 minimum biofilm inhibition concentration (MBIC). Expression levels of the genes encoding laminin binding protein (eno), elastin binding protein (ebps) and fibrinogen binding protein (fib) in the presence of TC at 1/2 MBIC were lower than in untreated biofilm in both the weakly and strongly adhering strain. The highest decrease of expression level was observed in case of fib in the strongly adhering strain, in which the amount of fib transcript was 10-fold lower compared to biofilm without TC. In the presence of TC at 1/2 MBIC after 3, 6, 8 and 12 h, the expression level of icaA and icaD, that are involved in the biosynthesis of polysaccharide intercellular adhesin, was above half lower in the weakly adhering strain compared to biofilm without TC. In the strongly adhering strain the highest decrease in expression of these genes was observed after 3 and 6 h. This study showed that TC is a promising anti-biofilm agent for use in MRSA biofilm-related infections.},
}
@article {pmid31877605,
year = {2019},
author = {Yu, JA and Gao, XX},
title = {[Bacterial biofilm and chronic wound infection].},
journal = {Zhonghua shao shang za zhi = Zhonghua shaoshang zazhi = Chinese journal of burns},
volume = {35},
number = {12},
pages = {842-847},
doi = {10.3760/cma.j.issn.1009-2587.2019.12.003},
pmid = {31877605},
issn = {1009-2587},
support = {20160101141JC//Natural Science Foundation of Jilin Province of China/ ; },
abstract = {Bacteria usually colonize, reproduce, and grow aggressively on chronic wounds in the form of biofilm. Different from free bacteria, bacteria in biofilm exhibit unique mechanism in epigenetics and biological behavior, especially in resistance to antibiotics and host immunity. In this article, we introduce the composition and structural function of bacterial biofilm, expound the drug-resistance mechanism of bacterial biofilm, discuss the clinical characteristics of bacterial biofilm infection wound and the diagnosis method of biofilm, and analyze the treatment strategy for bacterial biofilm. It is suggested that clinicians should pay more attention to bacterial biofilm infection and advocate in-depth study of bacterial biofilm in order to improve the quality of managing chronic wounds.},
}
@article {pmid31877028,
year = {2019},
author = {Mahasenan, KV and Batuecas, MT and De Benedetti, S and Kim, C and Rana, N and Lee, M and Hesek, D and Fisher, JF and Sanz-Aparicio, J and Hermoso, JA and Mobashery, S},
title = {Catalytic Cycle of Glycoside Hydrolase BglX from Pseudomonas aeruginosa and Its Implication in Biofilm Formation.},
journal = {ACS chemical biology},
volume = {},
number = {},
pages = {},
doi = {10.1021/acschembio.9b00754},
pmid = {31877028},
issn = {1554-8937},
abstract = {BglX is a heretofore uncharacterized periplasmic glycoside hydrolase (GH) of the human pathogen Pseudomonas aeruginosa. X-ray analy-sis identifies it as a protein homodimer. The two active sites of the homodimer comprise catalytic residues provided by each monomer. This arrangement is seen in less than 2% of the hydrolases of known structure. In vitro substrate profiling shows BglX is a catalyst for β-(1→2) and β-(1→3) saccharide hydrolysis. Saccharides with β-(1→4) or β-(1→6) bonds, and the β-(1→4) muropeptides from the cell-wall pep-tidoglycan, are not substrates. Additional structural insights from X-ray analysis (including structures of a mutant enzyme-derived Mich-aelis complex, two transition-state mimetics, and two enzyme-product complexes) enabled the comprehensive description of BglX catalysis. The half-chair (4H3) conformation of the transition-state oxocarbenium species, the approach of the hydrolytic water molecule to the oxocarbenium species, and the stepwise release of the two reac-tion products were also visualized. The substrate pattern for BglX aligns with the [β-(1→2)-Glc]x and [β-(1→3)-Glc]x periplasmic osmo-regulated periplasmic glucans, and possibly with the Psl exopolysac-charides, of P. aeruginosa. Both polysaccharides are implicated in biofilm formation. Accordingly, we show that inactivation of the bglX gene of P. aeruginosa PAO1 attenuates biofilm formation.},
}
@article {pmid31875569,
year = {2019},
author = {Lv, PL and Shi, LD and Dong, QY and Rittmann, B and Zhao, HP},
title = {How nitrate affects perchlorate reduction in a methane-based biofilm batch reactor.},
journal = {Water research},
volume = {171},
number = {},
pages = {115397},
doi = {10.1016/j.watres.2019.115397},
pmid = {31875569},
issn = {1879-2448},
abstract = {Nitrate (NO3-) affected perchlorate (ClO4-) reduction in a membrane batch biofilm reactor (MBBR), even though the electron donor, CH4, was available well in excess of its demand. For example, the perchlorate-reduction rate was 1.7 mmol/m2-d when perchlorate was the sole electron acceptor, but it dropped to 0.64 mmol/m2-d when nitrate also was present. The perchlorate-reduction rate returned to 1.60 mmol/m2-d after all nitrate was consumed. Denitratisoma and Azospirillum were main genera involved in perchlorate and nitrate reduction, and both could utilize NO3- and ClO4- as electron acceptors. Results of the reverse transcription-polymerase chain reaction (RT-PCR) showed that transcript abundances of nitrate reductase (narG), nitrite reductase (nirS), and perchlorate reductase (pcrA) increased when the perchlorate and nitrate concentrations were higher. Specifically, pcrA transcripts correlated to the sum of perchlorate and nitrate, rather than perchlorate individually. Analysis based on Density Functional Theory (DFT) suggests that bacteria able to utilize both acceptors, preferred NO3- over ClO4- due to nitrate reduction having lower energy barriers for proton and electron transfers.},
}
@article {pmid31874434,
year = {2019},
author = {Xu, S and Xing, Y and Liu, S and Luo, X and Chen, W and Huang, Q},
title = {Co-effect of minerals and Cd(II) promoted the formation of bacterial biofilm and consequently enhanced the sorption of Cd(II).},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {258},
number = {},
pages = {113774},
doi = {10.1016/j.envpol.2019.113774},
pmid = {31874434},
issn = {1873-6424},
abstract = {Heavy metal pollution is very common in soils. Soils are complex systems including minerals, bacteria, and various other substances. In Cd(II) contaminated soil, the combined effects of clay minerals and heavy metals on bacterial biofilm and Cd(II) adsorption are unappreciated. Our study showed that the combination of clay minerals (goethite, kaolinite, and montmorillonite) and heavy metals promoted Serratia marcescens S14 biofilm development significantly more than clay minerals or Cd(II) alone. The amount of biofilm after binary treatment with clay minerals and Cd(II) was 2.3-7.3 times than that in control. Mineral-induced cell death and the expression of the fimA, bsmA, and eps were key players in biofilm formation. Binary treatment with montmorillonite and Cd(II) significantly enhanced biofilm development and consequently increased the adsorption of Cd(II). Cd(II) removal is the result of co-adsorption of bacteria and minerals. Bacterial biofilm played an important role in Cd(II) adsorption. FTIR spectroscopy showed the components of biofilm were not affected by minerals and revealed the functional groups -OH, -NH, -CH2, -SH, -COO participated in Cd(II) immobilization. Our findings are of fundamental significance for understanding how minerals and Cd(II) affect biofilms and thereby enhance Cd(II) adsorption and predicting the mobility and fate of heavy metals in heavy metal-contaminated soil.},
}
@article {pmid31874422,
year = {2019},
author = {Wang, L and Chen, W and Song, X and Li, Y and Zhang, W and Zhang, H and Niu, L},
title = {Cultivation substrata differentiate the properties of river biofilm EPS and their binding of heavy metals: A spectroscopic insight.},
journal = {Environmental research},
volume = {182},
number = {},
pages = {109052},
doi = {10.1016/j.envres.2019.109052},
pmid = {31874422},
issn = {1096-0953},
abstract = {River biofilms inevitably serve as recipients of heavy metals including copper (Cu) and cadmium (Cd) following their introduction in fluvial systems. Nevertheless, the effects of cultivation substrata on the characteristics of river biofilm extracellular polymeric substances (EPS) and the binding behaviors of heavy metals on biofilms remain unclear. Integrating spectroscopic methods with chemometric analyses, we explored the binding behaviors of Cu(II) and Cd(II) onto biofilm EPS cultivated from two representative substrata at the molecular level. Chemical analysis revealed that biofilm cultivated on polyethylene (PE) pieces contained more non-fluorescent protein fractions, whereas EPS from periphyton grown on mineral, i.e., cobblestones was richer in aromatic fractions and polysaccharides. Excitation-emmision matrix combined with parallel factor analysis suggested a stronger interaction between fluorophores in periphytic EPS with Cu(II) compared to fluorophores in plastic biofilm EPS. Integrated use of infrared spectroscopy and two-dimensional correlation analyses revealed that, during the heavy metal binding processes, the amines and phenolics in plastic biofilm EPS gave the fastest responses to metal binding. While the amides and the aliphatic fractions in periphytic EPS showed a preferential binding to heavy metals. This study differentiates the effects of cultivation substrata on structuring the biofilm EPS characteristics and offers new insights into the environmental behaviors of heavy metal discharge into fluvial systems in river biofilm matrix.},
}
@article {pmid31873260,
year = {2019},
author = {Wadia, R},
title = {Biofilm removal.},
journal = {British dental journal},
volume = {227},
number = {12},
pages = {1041},
doi = {10.1038/s41415-019-1110-0},
pmid = {31873260},
issn = {1476-5373},
}
@article {pmid31873259,
year = {2019},
author = {Wadia, R},
title = {Biofilm as a risk factor in implant treatment.},
journal = {British dental journal},
volume = {227},
number = {12},
pages = {1041},
doi = {10.1038/s41415-019-1055-3},
pmid = {31873259},
issn = {1476-5373},
}
@article {pmid31871084,
year = {2019},
author = {Kolenda, C and Josse, J and Medina, M and Fevre, C and Lustig, S and Ferry, T and Laurent, F},
title = {Evaluation of the activity of a combination of three bacteriophages alone or in association with antibiotics on Staphylococcus aureus embedded in biofilm or internalised in osteoblasts.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1128/AAC.02231-19},
pmid = {31871084},
issn = {1098-6596},
abstract = {Background: Staphylococcus aureus is responsible for difficult-to-treat bone and joint infections (BJIs). This is related to its ability to form biofilm, and to be internalised and persist inside osteoblasts. Recently, bacteriophage therapy has emerged as a promising option to improve treatment of such infections but data on its activity against the specific bacterial lifestyles presented above remain scarce.Methods: We evaluated the activity of a combination of three bacteriophages, recently used for compassionate treatment in France, against S. aureus HG001 in a model of staphylococcal biofilm and a model of osteoblasts infection, alone or in association with vancomycin or rifampicin.Results: The activity of bacteriophages against biofilm-embedded S. aureus was dose-dependent. In addition, synergistic effects were observed when bacteriophages were combined with antibiotics used at the lowest concentrations. Phage penetration into osteoblasts was observed only when the cells were infected, suggesting a S. aureus-dependent Trojan horse mechanism for internalisation. The intracellular bacterial count of bacteria in infected osteoblasts treated with bacteriophages, as well as with vancomycin, was significantly higher than in cells treated with lysostaphin, used as control condition, owing to the absence of intracellular activity, and the rapid killing of bacteria released after death of infected cells. These results suggest that bacteriophages are both inactive in the intracellular compartment after being internalised in infected osteoblasts, and present a delayed killing effect on bacteria released after cell lysis into the extracellular compartment which avoid to prevent them from infecting other osteoblasts.Conclusion: The combination of bacteriophages tested was highly active against S. aureus embedded in biofilm but showed no activity against intracellular bacteria in the cell model used.},
}
@article {pmid31870707,
year = {2019},
author = {Lin, S and Rong, K and Lamichhane, KM and Babcock, RW and Kirs, M and Cooney, MJ},
title = {Anaerobic-aerobic biofilm-based digestion of chemical contaminants of emerging concern (CEC) and pathogen indicator organisms in synthetic wastewater.},
journal = {Bioresource technology},
volume = {},
number = {},
pages = {122554},
doi = {10.1016/j.biortech.2019.122554},
pmid = {31870707},
issn = {1873-2976},
abstract = {The efficacy of biofilm based anaerobic-aerobic treatment to reduce caffeine, carbamazepine, and three estrogens (Estrone (E1), 17β-estradiol (E2), and 17α-ethynylestradiol (EE2)), as well as E. coli (CN-13) and F+ specific coliphage (MS2), from synthetic wastewater was investigated. Results showed no observable reduction of carbamazepine by either anaerobic or aerobic biofilms over a dosing period of 51-days followed by an additional 23 days of observation. Caffeine, by contrast, was reduced by 11.09% in the upflow anaerobic packed bed biofilm reactor (UAnPBBR) and by 91.90% in the aerobic trickling filter biofilm reactor (TF). Estrone (E1) and 17β-estradiol (E2) showed minimal reduction in the UAnPBBR but 99.67% reduction in the TF, while EE2 was reduced 1.62% in the AnPBBR and 20.36% in the TF. On average, a 3-log reduction of E. coli (CN-13) and a 1-log reduction of F+ specific coliphage (MS2) concentration was observed across the overall reactor system.},
}
@article {pmid31870585,
year = {2019},
author = {Abrantes, PMDS and Africa, CWJ},
title = {Measuring Streptococcus mutans, Streptococcus sanguinis and Candida albicans biofilm formation using a real-time impedance-based system.},
journal = {Journal of microbiological methods},
volume = {},
number = {},
pages = {105815},
doi = {10.1016/j.mimet.2019.105815},
pmid = {31870585},
issn = {1872-8359},
abstract = {Candida albicans and streptococci are amongst the most common fungal and bacterial organisms present in the oral cavity, with a growing body of evidence implicating C. albicans in increased caries severity and in the formation of the cariogenic biofilm. However, the interactive mechanisms between cariogenic streptococci and Candida are yet to be elucidated. In this study, the real-time biofilm formation of C. albicans, S. mutans and S. sanguinis was assessed individually and in combination using the xCELLigence system, an impedance-based microbial biofilm monitoring system. The impedance signal was the highest for C. albicans, followed by S. mutans and S. sanguinis. Although the streptococcal mixed adhesion was found to follow a similar trend to that of S. sanguinis, the introduction of C. albicans resulted in higher adhesion patterns, with the combined growth of S. sanguinis and C. albicans and the combination of all three species resulting in higher biofilm formation than any of the individual organisms over time. This study, the first to use impedance for real-time monitoring of interkingdom biofilms, adds to the body of evidence that C. albicans and oral streptococcal adhesion are interlinked and suggests that interkingdom interactions induce changes in the oral biofilm dynamics over time.},
}
@article {pmid31869669,
year = {2019},
author = {Zhou, M and Xu, Y and Ouyang, P and Ling, J and Cai, Q and Huang, L and Zhou, X and Zheng, L},
title = {Evolution and distribution of resistance genes and bacterial community in water and biofilm of a simulated fish-duck integrated pond with stress.},
journal = {Chemosphere},
volume = {245},
number = {},
pages = {125549},
doi = {10.1016/j.chemosphere.2019.125549},
pmid = {31869669},
issn = {1879-1298},
abstract = {Integrated fish-duck pond is a common circular farming model in South China, besides, it is also hot-spot for the co-selection of antibiotic resistance genes (ARGs). The aim of this study was to investigate the effects of duck manure, As and cefotaxime on the bacterial community, and the evolution and distribution of ARGs and metal(loid) resistance genes (MRGs) in water and biofilm. Five groups of fish tanks included a control and four test groups. The experimental period lasted for 100 days. Six ARGs (CIT, DHA, EBC, FOX, MOX, TEM), two MRGs (arsB, arsC), and two integron genes (intI1, intI2) were tracked and detected in water and biofilm. The results showed that duck manure brought ARGs and MRGs into fish tanks. Stress factors (cefotaxime, As) increased the relative abundance of resistance genes, and this was positively correlated with stress concentrations. The biofilm was visible significantly at the end of stage 3, and the total relative abundance of resistance genes in biofilm was higher than water from stage 5 onwards. Evolution of AmpC β-lactamase resistance genes was more obvious than MRGs, especially for MOX, which increased by 3 orders of magnitude. The abundance of Flavobacterium was higher in biofilm than in water. Moreover, correlation analysis showed that both arsB and MOX were significantly correlated with intI1 (p < 0.05), which suggested a potentially dissemination risk of resistance genes. This study provides a reference for health risk assessment in integrated aquaculture environment contaminated with duck manure, antibiotics and metalloids.},
}
@article {pmid31869602,
year = {2019},
author = {Chien, HW and Chen, XY and Tsai, WP and Lee, M},
title = {Inhibition of biofilm formation by rough shark skin-patterned surfaces.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {186},
number = {},
pages = {110738},
doi = {10.1016/j.colsurfb.2019.110738},
pmid = {31869602},
issn = {1873-4367},
abstract = {In this study, we investigate the microscale structure of shark skin denticles at abdomen (A) and fin (F) locations, analyze the roughness and wetting properties related to their microstructures, and evaluate the effect of the surface properties on early bacterial attachment and biofilm formation. Microstructural analysis by scanning electron microscopy and confocal laser scanning microscopy confirmed the length (A: 165-180 μm vs. F: 145-165 μm), width (A: 86-100 μm vs. F: 64-70 μm), height (A: 10.5-13.5 μm vs. F: 6.2-8.8 μm), and density (A: 110-130 denticles/mm2vs. F: 80-130 denticles/mm2) of the denticles. The results showed that the roughness and hydrophobicity properties were affected with slight differences in the microscale architecture. The denticles with a larger width, higher ridge, and denser overlap provided a rougher and more hydrophobic surface. The microscale structure not only affected surface properties but also the biological attachment process. The microscale topography of shark skin slightly promoted bacterial attachment at an early stage, but prevented bacteria from developing biofilms. This systematic investigation provides insights into the effects of the surface topography of shark skin on its anti-fouling mechanism, which will enable the future development of various products related to human activity, such as healthcare products, underwater devices and applications, and water treatment applications.},
}
@article {pmid31865470,
year = {2019},
author = {Matamp, N and Bhat, SG},
title = {Genome characterization of novel lytic Myoviridae bacteriophage ϕVP-1 enhances its applicability against MDR-biofilm-forming Vibrio parahaemolyticus.},
journal = {Archives of virology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00705-019-04493-6},
pmid = {31865470},
issn = {1432-8798},
abstract = {A pathogen of significance in the aquaculture sector, the Gram-negative marine bacterium Vibrio parahaemolyticus causes gastroenteritis associated with consumption of improperly prepared seafood. This bacterium can be controlled using lytic bacteriophages as an alternative to antibiotics. ϕVP-1 is a lytic phage of V. parahaemolyticus that was isolated from an aquafarm water sample with the aim of assessing its potential as a bio-control agent and determining its physicochemical properties and genomic sequence. Morphological analysis by transmission electron microscopy and phylogenetic analysis based on the large terminase subunit gene showed that this phage belongs to the family Myoviridae. It could infect multiple-drug-resistant (MDR) V. parahaemolyticus and V. alginolyticus strains of mangrove and seafood origin. With a maximum adsorption time of 30 min, ϕVP-1 has a short latent period of 10 min with burst size of 44 particles/cell. Whole-genome sequencing was done using the Illumina platform, and annotation was done using GeneMarkS and Prodigal. The 150,764bp genome with an overall G+C content of 41.84% had 203 putative protein-encoding open reading frames, one tRNA gene, and 66 predicted promoters. A number of putative DNA replication and regulation, DNA packaging and structure, and host lysis genes were identified. Comparison of the ϕVP-1 genome sequence to those of known Vibrio phages indicated little discernible DNA sequence similarity, suggesting that ϕVP-1 is a novel Vibrio phage. Sequence analysis revealed the presence of 64 potential ORFs with a T4-like genomic organization. In silico analysis suggested an obligate lytic life cycle and showed the absence of lysogeny or virulence genes. The complete sequence of ϕVP-1 was annotated and deposited in the GenBank database (accession no. MH363700). The genetic features of this novel phage suggest that it might be applicable for phage therapy against pathogenic strains of V. parahaemolyticus.},
}
@article {pmid31865430,
year = {2019},
author = {Hassan, HA and Ding, X and Zhang, X and Zhu, G},
title = {Fish borne Edwardsiella tardaeha involved in the bacterial biofilm formation, hemolytic activity, adhesion capability and pathogenicity.},
journal = {Archives of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00203-019-01794-x},
pmid = {31865430},
issn = {1432-072X},
support = {KYCX19_2116//Postgraduate Research &amp; Practice Innovation Program of Jiangsu Province/ ; },
abstract = {Edwardsiella tarda (E. tarda) is distributed widely in a variety of hosts including humans, other mammals and fish, and it is worthwhile to notice that E. tarda -caused fish infections lead to the most important bacterial disease in fish. Considering Eha acting as a transcriptional regulator in E. tarda strain ET13 have been reported previously, to better understand its pathogenesis due to this, a type of cell of epithelial cell line (Caco-2) infection model for the pathogen was established in the laboratory. We focused on studying various parameters such as lactate dehydrogenase release (to measure cytotoxicity) and cell adhesions, both of which are related to the bacterial pathogenesis. Furthermore biofilm formation, hemolytic activity, and adhesion to Caco-2 cells were decreased in an E.tarda mutant strain with deletion in-frame isogenic gene eha (∆eha) compared to the wild-type and the complementary strain eha+ (an engineered construct of ∆eha expressing eha); Meanwhile, we found that hemolytic activity and biofilm formation were significantly enhanced in the strain eha+. Moreover, the ∆eha strain had attenuated pathogenicity in the zebrafish infection model. The data also demonstrated that the series of genes fimA, esrB, gadB, mukF, katB, and katG are regulated by eha based on a quantitative reverse transcription polymerase chain reaction tests and analysis. Thus our research data indicated that eha has an impact on hemolytic activity, biofilm formation, adhesion, and pathogenicity of pathogenic strain ET13 and plays an essential role in manifesting the virulence factors.},
}
@article {pmid31865379,
year = {2019},
author = {Alam, F and Catlow, D and Di Maio, A and Blair, JMA and Hall, RA},
title = {Candida albicans enhances meropenem tolerance of Pseudomonas aeruginosa in a dual-species biofilm.},
journal = {The Journal of antimicrobial chemotherapy},
volume = {},
number = {},
pages = {},
doi = {10.1093/jac/dkz514},
pmid = {31865379},
issn = {1460-2091},
abstract = {BACKGROUND: Pseudomonas aeruginosa is an opportunistic bacterium that infects the airways of cystic fibrosis patients, surfaces of surgical and burn wounds, and indwelling medical devices. Patients are prone to secondary fungal infections, with Candida albicans being commonly co-isolated with P. aeruginosa. Both P. aeruginosa and C. albicans are able to form extensive biofilms on the surfaces of mucosa and medical devices.<br><br>OBJECTIVES: To determine whether the presence of C. albicans enhances antibiotic tolerance of P. aeruginosa in a dual-species biofilm.<br><br>METHODS: Single- and dual-species biofilms were established in microtitre plates and the survival of each species was measured following treatment with clinically relevant antibiotics. Scanning electron microscopy and confocal microscopy were used to visualize biofilm structure.<br><br>RESULTS: C. albicans enhances P. aeruginosa biofilm tolerance to meropenem at the clinically relevant concentration of 5 mg/L. This effect is specific to biofilm cultures and is dependent upon C. albicans extracellular matrix polysaccharides, mannan and glucan, with C. albicans cells deficient in glycosylation structures not enhancing P. aeruginosa tolerance to meropenem.<br><br>CONCLUSIONS: We propose that fungal mannan and glucan secreted into the extracellular matrix of P. aeruginosa/C. albicans dual-species biofilms play a central role in enhancing P. aeruginosa tolerance to meropenem, which has direct implications for the treatment of coinfected patients.},
}
@article {pmid31864088,
year = {2019},
author = {Saravanakumar, K and Jeevithan, E and Hu, X and Chelliah, R and Oh, DH and Wang, MH},
title = {Enhanced anti-lung carcinoma and anti-biofilm activity of fungal molecules mediated biogenic zinc oxide nanoparticles conjugated with β-D-glucan from barley.},
journal = {Journal of photochemistry and photobiology. B, Biology},
volume = {203},
number = {},
pages = {111728},
doi = {10.1016/j.jphotobiol.2019.111728},
pmid = {31864088},
issn = {1873-2682},
abstract = {This work reports the optimization, synthesis, characterization, anticancer, and antibacterial activity of the Trichoderma-β-D-glucan‑zinc oxide nanoparticles (T-β-D-glu-ZnO NPs). Firstly, the T-ZnO NPs was synthesized using the fungal mycellial water extract (FWME) derived from T. harzianum (SKCGW009) under the optimized condition of extract concentration (5.99 mL), temperature (43.11 °C), pH (8) and time (69.04 h). The successful conjugation of T-ZnO NPs with β-D-glucan (T-β-D-glu-ZnO NPs) was confirmed by PACE and FTIR. The XRD, UHR SEM, and TEM EDS results pointed the spherical shape of NPs with the mean size of 30.34 nm. Further, the XPS survey scan and high-resolution fitting of Zn2p results also claimed the successful formation of the T-β-D-glu-ZnO NPs. Cytotoxicity results indicated that the NPs were not toxic to NIH3T3 cells, while exhibited the dose-dependent inhibitory effect to human pulmonary carcinoma A549 cells. The IC50 of T-ZnO NPs and T-β-D-glu-ZnO NPs against A549 cells was 158 and 56.25 μg.mL-1, respectively, which was also verified by fluorescent cytochemistry. Annexin V-FITC staining results indicated the presence of apoptotic cells in the NPs treated A549 cells, which was not seen in the non-treated control A549 cells. Interestingly, the number of necrosis cells was higher in the T-ZnO NPs (3.38%) comparing to T-β-D-glu -ZnO NPs (0.07%). The early or late apoptosis was found higher in the cells treated T-β-D-glu -ZnO NPs (6.43%) comparing with T-ZnO NPs (4%). These results indicated that T-ZnO NPs and T-β-D-glu-ZnO NPs induced the cancer cell death through necrosis and apoptosis pathway, respectively. The antibacterial results indicated that the NPs treatment were significantly inhibited the growth of the Staphylococcus aureus inside of roundworm and enhanced growth of roundworm. Overall, anticancer and in vitro, in vivo antibacterial studies proved the high caliber of T-β-D-glu-ZnO NPs for the further pharmaceutical evaluation.},
}
@article {pmid31863153,
year = {2019},
author = {Beck, S and Sehl, C and Voortmann, S and Verhasselt, HL and Edwards, MJ and Buer, J and Hasenberg, M and Gulbins, E and Becker, KA},
title = {Sphingosine is able to prevent and eliminate Staphylococcus epidermidis biofilm formation on different orthopedic implant materials in vitro.},
journal = {Journal of molecular medicine (Berlin, Germany)},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00109-019-01858-x},
pmid = {31863153},
issn = {1432-1440},
support = {Gu 335/34-1//Deutsche Forschungsgemeinschaft/ ; },
abstract = {Periprosthetic infection (PPI) is a devastating complication in joint replacement surgery. On the background of an aging population, the number of joint replacements and associated complications is expected to increase. The capability for biofilm formation and the increasing resistance of different microbes to antibiotics have complicated the treatment of PPI, requiring the need for the development of alternative treatment options. The bactericidal effect of the naturally occurring amino alcohol sphingosine has already been reported. In our study, we demonstrate the antimicrobial efficacy of sphingosine on three different strains of biofilm producing Staphylococcus epidermidis, representing one of the most frequent microbes involved in PPI. In an in vitro analysis, sphingosine's capability for prevention and treatment of biofilm-contamination on different common orthopedic implant surfaces was tested. Coating titanium implant samples with sphingosine not only prevented implant contamination but also revealed a significant reduction of biofilm formation on the implant surfaces by 99.942%. When testing the antimicrobial efficacy of sphingosine on sessile biofilm-grown Staphylococcus epidermidis, sphingosine solution was capable to eliminate 99.999% of the bacteria on the different implant surfaces, i.e., titanium, steel, and polymethylmethacrylate. This study provides evidence on the antimicrobial efficacy of sphingosine for both planktonic and sessile biofilm-grown Staphylococcus epidermidis on contaminated orthopedic implants. Sphingosine may provide an effective and cheap treatment option for prevention and reduction of infections in joint replacement surgery. KEY MESSAGES: • Here we established a novel technology for prevention of implant colonization by sphingosine-coating of orthopedic implant materials. • Sphingosine-coating of orthopedic implants prevented bacterial colonization and significantly reduced biofilm formation on implant surfaces by 99.942%. • Moreover, sphingosine solution was capable to eliminate 99.999% of sessile biofilm-grown Staphylococcus epidermidis on different orthopedic implant surfaces.},
}
@article {pmid31863146,
year = {2019},
author = {Shin, B and Park, C and Park, W},
title = {OxyR-controlled surface polysaccharide production and biofilm formation in Acinetobacter oleivorans DR1.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-019-10303-5},
pmid = {31863146},
issn = {1432-0614},
support = {NRF-2019R1A2C1088452//National Research Foundation of Korea/ ; },
abstract = {The genomes of several Acinetobacter species possess three distinct polysaccharide-producing operons [two poly-N-acetyl glucosamine (PNAG) and one K-locus]. Using a microfluidic device, an increased amount of polysaccharides and enhanced biofilm formation were observed following continuous exposure to H2O2 and removal of the H2O2-sensing key regulator, OxyR, in Acinetobacter oleivorans DR1 cells. Gene expression analysis revealed that genes located in PNAG1, but not those in PNAG2, were induced and that genes in the K-locus were expressed in the presence of H2O2. Interestingly, the expression of the K-locus gene was enhanced in the PNAG1 mutant and vice versa. The absence of either OxyR or PNAG1 resulted in enhanced biofilm formation, higher surface hydrophobicity, and increased motility, implying that K-locus-driven polysaccharide production in both the oxyR and PNAG1 deletion mutants may be related to these phenotypes. Both the oxyR and K-locus deletion mutants were more sensitive to H2O2 compared with the wildtype and PNAG1 mutant strains. Purified OxyR binds to the promoter regions of both polysaccharide operons with a higher affinity toward the K-locus promoter. Although oxidized OxyR could bind to both promoter regions, the addition of dithiothreitol further enhanced the binding efficiency of OxyR, suggesting that OxyR might function as a repressor for controlling these polysaccharide operons.},
}
@article {pmid31863074,
year = {2019},
author = {Kim, D and Lee, MJ and Kim, JY and Lee, D and Kwon, JS and Choi, SH},
title = {Incorporation of zwitterionic materials into light-curable fluoride varnish for biofilm inhibition and caries prevention.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {19550},
pmid = {31863074},
issn = {2045-2322},
abstract = {We incorporated zwitterionic materials into light-curable fluoride varnish (LCFV) in order to inhibit biofilm accumulation and prevent dental caries, and the properties of LCFV with three different zwitterionic materials, namely, 2-methacryloyloxyethyl phosphorylcholine (MPC), carboxybetaine methacrylate (CBMA), and sulfobetaine methacrylate (SBMA) polymers (each at a weight percentage of 3%), were compared; unmodified LCFV without any zwitterionic material was used as a control. Material properties including film thickness and degree of conversion (DC) of each type of LCFV were evaluated. In addition, protein-repellent effects and inhibitory effects on Streptococcus mutans adhesion and saliva-derived biofilm accumulation of LCFV were estimated. Finally, the preventive effect of LCFV on enamel demineralization was assessed in vitro on extracted human teeth specimens stored in S. mutans-containing medium. The film thickness of LCFV significantly decreased with the incorporation of zwitterionic materials compared to the control LCFV, whereas there were no significant differences in the DC among all of the LCFV groups. Furthermore, the amount of adsorbed protein, adherent S. mutans colony-forming unit (CFU) counts, and saliva-derived biofilm thickness and biomass were all significantly lower for LCFV with incorporated zwitterionic materials compared with the control. All LCFV groups including the control showed certain preventive effects against enamel demineralization during a 14-day immersion in the medium with S. mutans and sucrose, and the depth of demineralization was significantly lower in LCFV with zwitterionic materials than in the control. Thus, the incorporation of zwitterionic materials such as MPC, CBMA, and SBMA appears to confer superior antifouling effects to LCFV.},
}
@article {pmid31862721,
year = {2019},
author = {Glatthardt, TDSDS and Campos, JCM and Chamon, RC and Coimbra, TFS and Rocha, GA and de Melo, MAF and Parente, TE and Lobo, LA and Antunes, LCM and Dos Santos, KRN and Ferreira, RBR},
title = {Small molecules produced by commensal Staphylococcus epidermidis disrupt biofilm formation by Staphylococcus aureus.},
journal = {Applied and environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1128/AEM.02539-19},
pmid = {31862721},
issn = {1098-5336},
abstract = {The microbiota influences host health through several mechanisms, including by protecting it from pathogen colonization. Staphylococcus epidermidis is one of the most frequently found species in the skin microbiota, and its presence can limit the development of pathogens, such as Staphylococcus aureusS. aureus causes diverse types of infections ranging from skin abscesses to bloodstream infections. Given the increasing prevalence of S. aureus drug-resistant strains, it is imperative to search for new strategies for treatment and prevention. Thus, we investigated the activity of molecules produced by a commensal S. epidermidis isolate against S. aureus biofilms. We showed that molecules present in S. epidermidis cell-free conditioned media caused a significant reduction in biofilm formation in most of S. aureus clinical isolates, including all 4 agr types and agr defective strains, without any impact on growth. S. epidermidis molecules also disrupted established S. aureus biofilms and reduced the antibiotic concentration required to eliminate them. Preliminary characterization of the active compound showed that its activity is resistant to heat, protease inhibitors, trypsin, proteinase K, and sodium periodate treatments, suggesting that it is not proteinaceous. RNA sequencing revealed that S. epidermidis secreted molecules modulate the expression of hundreds of S. aureus genes, some of which are associated with biofilm production. Biofilm formation is one of the main virulence factors of S. aureus and has been associated with chronic infections and antimicrobial resistance. Therefore, molecules that can counteract this virulence factor may be promising alternatives as novel therapeutic agents to control of S. aureus infections.IMPORTANCE.S. aureus is a leading agent of infections worldwide and its main virulence factor is the ability to produce biofilms on surfaces, such as medical devices. Biofilms are known to confer increased resistance to antimicrobials and to the host immune responses, requiring aggressive antibiotic treatment and removal of the infected surface. Here, we investigated a new source of anti-biofilm compounds, the skin microbiome. Specifically, we found that a commensal strain of S. epidermidis produces molecules with anti-biofilm activity, leading to a significant decrease on S. aureus biofilm formation and to reduction of previously established biofilms. The molecules potentiated the activity of antibiotics and affected the expression of hundreds of S. aureus genes, including those associated with biofilm formation. Our research highlights the search for compounds that can aid us in the fight against S. aureus infections.},
}
@article {pmid31862559,
year = {2019},
author = {Shi, Z and Zhang, Y and Dai, R and Chen, S and Zhang, M and Jin, L and Wang, J and Zhao, W and Zhao, C},
title = {Rationally designed magnetic poly(catechol-hexanediamine) particles for bacteria removal and on-demand biofilm eradication.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {186},
number = {},
pages = {110728},
doi = {10.1016/j.colsurfb.2019.110728},
pmid = {31862559},
issn = {1873-4367},
abstract = {In this study, we proposed a green, facile and low-cost approach for the fabrication of multifunctional particles with robust bacteria removal capability and on-demand biofilm eradication activity. Based on mussel-inspired coating of catechol and hexanediamine on Fe3O4 in aqueous solution, magnetic poly(catechol-hexanediamine) particles (Fe3O4@HDA) were prepared successfully in 1 h, at room temperature. Microbiological experiments demonstrated the Fe3O4@HDA particles could capture bacteria in water efficiently. Meanwhile, with an integration of magnetic response property and near-infrared-triggered photothermal bactericidal activity, the Fe3O4@HDA particles showed a high potential for biofilm targeting and in-situ eradication. We believe that the rationally designed magnetic poly(catechol-hexanediamine) particles could extend the applications of smart antimicrobial agents to industrial fields such as water disinfection and biofouling clean-up.},
}
@article {pmid31862392,
year = {2019},
author = {Prateeksha, and Bajpai, R and Yusuf, MA and Upreti, DK and Gupta, VK and Singh, BN},
title = {Endolichenic fungus, Aspergillus quandricinctus of Usnea longissima inhibits quorum sensing and biofilm formation of Pseudomonas aeruginosa PAO1.},
journal = {Microbial pathogenesis},
volume = {},
number = {},
pages = {103933},
doi = {10.1016/j.micpath.2019.103933},
pmid = {31862392},
issn = {1096-1208},
abstract = {Lichens are composite organisms, comprising of a fungus (mycobiont) and a blue-green alga (photobiont). Along with the mycobiont, numerous non-obligate microfungi live in lichen thalli. These microfungi are called endolichenic fungi (ELF). In recent years, the ELF are emerging as promising natural sources because of their capability to exert unique drug molecules. The current study aimed to isolate the ELF from the lichen, Usnea longissima Ach., to control of biofilm formation and quorum sensing phenomenon in Pseudomonas aeruginosa PAO1, an opportunistic multidrug resistance pathogen that uses quorum sensing network to produce an array of pathogenic agents. Therefore, inhibiting quorum sensing to manage the infection caused by PAO1 could be the paramount alternative approach to conventional antibiotics. The isolated ELF was identified by amplifying the long subunit region of the fungal genome. The extracted metabolites of ELF (MELE) using the acetone solvent was further investigated for anti-quorum sensing activity using the biomarker strain Chromobacterium violaceum 12472 which exerts violacein pigment via the AHL mediated quorum sensing signalling. Moreover, the effect of MELE was also evaluated on the production of virulence factors and biofilm formation of P. aeruginosa PAO1. The molecular identification revealed that ELF (accession number MN171299) exhibited 100% similarity with Aspergillus quandricinctus strain CBS 135.52. The MELE showed significant anti-quorum sensing activity at the concentration of 4 mg/mL without affecting the bacterial cell viability of P. aeruginosa PAO1. The MELE diminished the production of virulence factors, including pyocyanin, protease, elastase, rhamnolipids, and extracellular polysaccharides of P. aeruginosa PAO1 in a concentration-dependent manner. The MELE also disturbed biofilm formation of P. aeruginosa PAO1. The 3-D analysis of biofilm architecture showed that the thickness and surface area covered by microcolonies was decreased as the concentration of MELE was increased. The GC-MS analysis of MELE exhibited that organic acids and fatty acids are major constituents of the MELE. The present study reports first time that the ELF, A. quandricinctus possesses potential to inhibit quorum sensing and biofilm formation of P. aeruginosa and can be further exploited for hospital and healthcare facilities.},
}
@article {pmid31861483,
year = {2019},
author = {Osman, KM and Kappell, AD and Fox, EM and Orabi, A and Samir, A},
title = {Prevalence, Pathogenicity, Virulence, Antibiotic Resistance, and Phylogenetic Analysis of Biofilm-Producing Listeria monocytogenes Isolated from Different Ecological Niches in Egypt: Food, Humans, Animals, and Environment.},
journal = {Pathogens (Basel, Switzerland)},
volume = {9},
number = {1},
pages = {},
doi = {10.3390/pathogens9010005},
pmid = {31861483},
issn = {2076-0817},
support = {25782//Science and Technology Development Fund/ ; },
abstract = {Serious outbreaks of foodborne disease have been caused by Listeria monocytogenes found in retail delicatessens and the severity of disease is significant, with high hospitalization and mortality rates. Little is understood about the formidable public health threat of L. monocytogenes in all four niches, humans, animals, food, and environment, in Egypt. This study analyzed the presence of L. monocytogenes collected from the four environmental niches and bioinformatics analysis was implemented to analyze and compare the data. PCR was used to detect virulence genes encoded by pathogenicity island (LIPI-1). prfA amino acid substation that causes constitutive expression of virulence was common in 77.7% of isolates. BLAST analysis did not match other isolates in the NCBI database, suggesting this may be a characteristic of the region associated with these isolates. A second group included the NH1 isolate originating in China, and BLAST analysis showed this prfA allele was shared with isolates from other global locations, such as Europe and North America. Identification of possible links and transmission pathways between the four niches helps to decrease the risk of disease in humans, to take more specific control measures in the context of disease prevention, to limit economic losses associated with food recalls, and highlights the need for treatment options.},
}
@article {pmid31859706,
year = {2019},
author = {Casarin, M and Pazinatto, J and Oliveira, LM and Souza, ME and Santos, RCV and Zanatta, FB},
title = {Anti-biofilm and anti-inflammatory effect of a herbal nanoparticle mouthwash: a randomized crossover trial.},
journal = {Brazilian oral research},
volume = {33},
number = {},
pages = {e062},
doi = {10.1590/1807-3107bor-2019.vol33.0062},
pmid = {31859706},
issn = {1807-3107},
abstract = {Laboratory evidence has demonstrated the antimicrobial effect of Melaleuca alternifolia (MEL) against oral microorganisms. This randomized, double-blind, crossover clinical trial, compared the anti-biofilm and anti-inflammatory effects of MEL nanoparticles with 0.12% chlorhexidine gluconate (CHX) on biofilm-free (BF) and biofilm-covered (BC) surfaces. Before each experimental period, the participants refrained from all oral hygiene practices for 72 hours. The 60 participants were randomly assigned to professional prophylaxis in two quadrants (Q1-Q3 or Q2-Q4), and rinsed with MEL or CHX for four days. The Quigley &amp; Hein plaque index (QHPI), gingival crevicular fluid (GCF) volume, and participants' perceptions were assessed. CHX showed significantly lower mean QHPI on BF (2.65 ± 0.34 vs. 3.34 ± 0.33, p < 0.05) and BC surfaces (2.84 ± 0.37 vs. 3.37 ± 0.33, p < 0.05). Intragroup comparisons indicated reductions in GCF in all the groups, with significant differences only for CHX on BF surfaces (p < 0.05). Intergroup comparisons revealed no significant differences (p > 0.05). Based on individual perceptions, CHX had better taste and biofilm control, but resulted in a greater change in taste. Nevertheless, MEL demonstrated anti-inflammatory effects similar to those of CHX. Further clinical trials testing different protocols, concentrations and follow-up periods are required to establish its clinical application.},
}
@article {pmid31858598,
year = {2019},
author = {Lee, HJ and Oh, SY and Hong, SH},
title = {Inhibition of streptococcal biofilm formation by Aronia via extracellular RNA degradation.},
journal = {Journal of the science of food and agriculture},
volume = {},
number = {},
pages = {},
doi = {10.1002/jsfa.10223},
pmid = {31858598},
issn = {1097-0010},
abstract = {BACKGROUND: Accumulation of oral bacterial biofilms is one of the primary etiological factors for oral diseases. Aronia melanocarpa extracts exert general health benefits, including antimicrobial activities. This study evaluates the inhibitory effect of Aronia juice on oral streptococcal biofilm formation.<br><br>RESULTS: Exposure to 1/10-diluted Aronia juice for 1 min significantly decreased in vitro streptococcal biofilm formation (P < 0.001). No remarkable difference was noted in streptococcal growth by Aronia under the same condition. Interestingly, 1 week of oral rinse with diluted Aronia juice led to significantly fewer salivary streptococcal colony-forming unit (CFU) relative to oral rinse with tap water (P < 0.05). Furthermore, Aronia exerted an extracellular RNA-degrading effect, and RNase inhibitor alleviated Aronia-dependent streptococcal biofilm inhibition.<br><br>CONCLUSION: Aronia might inhibit initial biofilm formation by decomposing extracellular RNA, which plays an important role in bacterial biofilm formation. Our data suggest that oral rinse with Aronia juice will aid in treating oral biofilm-dependent diseases with ease and efficiency. This article is protected by copyright. All rights reserved.},
}
@article {pmid31858084,
year = {2019},
author = {Rad, MR and Pourhajibagher, M and Rokn, AR and Barikani, HR and Bahador, A},
title = {Effect of Antimicrobial Photodynamic Therapy Using Indocyanine Green Doped with Chitosan Nanoparticles on Biofilm Formation-Related Gene Expression of Aggregatibacter actinomycetemcomitans.},
journal = {Frontiers in dentistry},
volume = {16},
number = {3},
pages = {187-193},
pmid = {31858084},
issn = {2676-296X},
abstract = {Objectives: Eradication of Aggregatibacter actinomycetemcomitans (A. actionmycetemcomitans), as an opportunistic periodontopathogen, and inhibition of its virulence factor expression require a new adjunctive therapeutic method. In this study, we accessed the expression level of rcpA gene, as a virulence factor associated with A. actinomycetemcomitans biofilm formation, following treatment by antimicrobial photodynamic therapy (aPDT) using indocyanine green (ICG) doped with chitosan nanoparticles (CS-NPs@ICG).<br><br>Materials and Methods: CS-NPs@ICG was synthesized and examined using scanning electron microscopy (SEM). A. actinomycetemcomitans ATCC 33384 strain was treated with CS-NPs@ICG, as a photosensitizer, which was excited with a diode laser at the wavelength of 810 nm with the energy density of 31.2 J/cm2. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to determine the changes in rcpA gene expression level.<br><br>Results: Synthetized CS-NPs@ICG was confirmed via SEM. The results revealed that CS-NPs@ICG-mediated aPDT could significantly decrease rcpA gene expression to 13.2-fold (P<0.05). There was a remarkable difference between aPDT using CS-NPs@ICG and ICG (P<0.05). The diode laser, ICG, and CS-NPs@ICG were unable to significantly downregulate rcpA gene expression (P>0.05).<br><br>Conclusion: aPDT with CS-NPs@ICG leads to a decrease of the virulence factor of A. actinomycetemcomitans and can be used as an adjunct to routine treatments for successful periodontal therapy in vivo.},
}
@article {pmid31856459,
year = {2020},
author = {Raksha, L and Gangashettappa, N and Shantala, GB and Nandan, BR and Sinha, D},
title = {Study of biofilm formation in bacterial isolates from contact lens wearers.},
journal = {Indian journal of ophthalmology},
volume = {68},
number = {1},
pages = {23-28},
doi = {10.4103/ijo.IJO_947_19},
pmid = {31856459},
issn = {1998-3689},
abstract = {Purpose: To detect biofilm forming capacity of bacterial isolates obtained from the conjunctiva, contact lens and accessories of contact lens wearers using phenotypic and genotypic methods.<br><br>Methods: Bacterial strains were collected from the conjunctiva, contact lens and lens storage cases of contact lens wearers. The phenotypic detection of biofilm production was done using the tube method and congo red agar method. The biofilm-forming related genes, icaA, of Coagulase negative Staphylococcus (CONS) and Staphylococcus aureus, and pslA, of P. aeruginosa, were detected using PCR.<br><br>Results: A total of 265 bacterial isolates which included S. aureus, CONS, Pseudomonas, Nil-fermenter Gram-negative bacilli (NFGNB), Bacillus spp, Diphtheroids, Micrococci, Klebsiella pneumonia, Klebsiella oxytoca, E. coli, Proteus mirabilis, Proteus vulgaris, Citrobacter koseri, Citrobacter freundii, Enterobacter cloacae, Moraxella were obtained. Of the 265 isolates, 53.5% were moderately positive, 33.2% strongly positive and 13.2% negative for biofilm production by tube method and 36.6% were moderately positive, 40% strongly positive and 23.3% negative for biofilm production by congo red agar method. Of the four S. aureus isolates, two (50%) showed the presence of icaA gene. Of the 23 CONS isolates, three (13%) showed the presence of icaA gene. All the Pseudomonas isolates were negative for presence pslA (1119 bp) gene though most of them were phenotypically positive for biofilm formation.<br><br>Conclusion: Most of the bacterial isolates obtained from contact lens wearers had the potential to produce biofilms. Tube method and Congo red agar method exhibited significant statistical correlation (P-value = 0.006) and picked up a good number of biofilm-forming isolates, hence may be used for detection of biofilm production. The absence of biofilm-forming gene did not rule out the possibility for phenotypic biofilm production by bacteria.},
}
@article {pmid31856361,
year = {2019},
author = {Chatterjee, S and Das, S},
title = {Developmental stages of biofilm and characterization of extracellular matrix of manglicolous fungus Aspergillus niger BSC-1.},
journal = {Journal of basic microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1002/jobm.201900550},
pmid = {31856361},
issn = {1521-4028},
support = {BT/PR9465/NDB/39/360/2013//Department of Biotechnology, Ministry of Science and Technology/ ; },
abstract = {Fungal biofilm is ubiquitous in natural environment. The major constituent of fungal biofilm other than biomass is the extracellular matrix (ECM), in which fungal hyphae are embedded. Physical properties of biofilms such as attachment, mechanical strength, and antibiotic resistance can be attributed to ECM. The present work probes various stages of biofilm formation by filamentous manglicolous fungus Aspergillus niger BSC-1. The spectroscopic analysis revealed that with an increase in incubation time the biofilm formation was significantly increased (p < .0001) up to 36 h. Scanning electron micrograph and confocal micrograph depicted the development of fungal biofilm comprising of six stages, that is, (a) adsorption, (b) active attachment, (c) germling and monolayer formation, (d) hyphal development and formation of ECM, (e) maturation of ECM, and (f) dispersal of spores. At maturation stage, thickness of biofilm was observed upto approximately 15 μm. Approximately, 8.1 mg of ECM materials were extracted from 20 ml of broth culture using ethanol precipitation method. Furthermore, attenuated total reflectance Fourier-transformed infrared spectroscopic analysis exhibited peaks at 3,398, 2,930, 1,571, 1,391, 1,092, 977 cm-1 which confirmed the presence of protein, carbohydrate, and lipid in the biofilm-associated matrix.},
}
@article {pmid31855718,
year = {2019},
author = {Yuan, L and Lyu, P and Huang, YY and Du, N and Qi, W and Hamblin, MR and Wang, Y},
title = {Potassium iodide enhances the photobactericidal effect of methylene blue on Enterococcus faecalis as planktonic cells and as biofilm infection in teeth.},
journal = {Journal of photochemistry and photobiology. B, Biology},
volume = {203},
number = {},
pages = {111730},
doi = {10.1016/j.jphotobiol.2019.111730},
pmid = {31855718},
issn = {1873-2682},
abstract = {OBJECTIVE: To explore the effectiveness, biosafety, photobleaching and mechanism of antimicrobial photodynamic therapy (aPDT) using methylene blue (MB) plus potassium iodide (KI), for root canal infections.<br><br>METHODS: Different combinations and concentrations of MB, KI and 660 nm LED light were used against E. faecalis in planktonic and in biofilm states by colony-forming unit (CFU), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM). Human gingival fibroblasts (HGF) were used for safety testing by Cell Counting Kit-8 (CCK8) and fluorescence microscopy (FLM). The photobleaching effect and mechanisms were analyzed.<br><br>RESULTS: KI could not only enhance MB aPDT on E. faecalis in both planktonic and biofilm states even in a hypoxic environment, but also produced a long-lasting bactericidal effect after end of the illumination. KI could accelerate photobleaching to reduce tooth staining by MB, and the mixture was harmless for HGFs. Mechanistic studies showed the generation of hydrogen peroxide and free iodine, and iodine radicals may be formed in hypoxia.<br><br>CONCLUSION: aPDT with MB plus KI could be used for root canal disinfection and clinical studies are worth pursuing.},
}
@article {pmid31855457,
year = {2019},
author = {Qian, W and Yang, M and Wang, T and Sun, Z and Liu, M and Zhang, J and Zeng, Q and Cai, C and Li, Y},
title = {Antibacterial mechanism of vanillic acid on physiological, morphological and biofilm properties of carbapenem-resistant Enterobacter hormaechei.},
journal = {Journal of food protection},
volume = {},
number = {},
pages = {},
doi = {10.4315/JFP-19-469},
pmid = {31855457},
issn = {1944-9097},
abstract = {Many studies on the evaluation of the antimicrobial activity of natural products have been conducted against various microorganisms, but the exploit of natural products meditated antimicrobial activity against Enterobacter hormaechei has not been found in the literature. In this study, we set up to investigate vanillic acid (VA)-mediated antimicrobial activities and its modes of action against carbapenem-resistant E. hormaechei (CREH). Minimum inhibitory concentration (MIC) of VA against CREH was examined by the agar diffusion method. Antibacterial mode of VA against CREH was elucidated by measuring variations in intracellular ATP concentration, intracellular pH, membrane potential, and cell morphology. Moreover, anti-biofilm formation of VA and its damage to CREH cells embedded in biofilms were further explored. Our results show that VA was effective against CREH with MIC of 0.8 mg/mL. VA could rupture cell membrane integrity of CREH, as measured by a decrease of intracellular ATP, pH and membrane potential, along with distinctive alternations in cell morphology. In addition, VA exerted a remarkable inhibitory effect on the biofilm formation of CREH and killed CREH cells within biofilms. These findings display that VA has a potent antibacterial and anti-biofilm activity against CREH, and hence has the potential to be exploited in clinic as a novel candidate agent to treat CREH infections and in the food industry as food preservatives and surface disinfectants.},
}
@article {pmid31854716,
year = {2019},
author = {Xu, LJ and Pan, Y and Zhang, H and Feng, X and Wei, PL and You, XY},
title = {[Effects of Aerobic Carbon Sources on Biofilm with Simultaneous Phosphate Removal and Enrichment].},
journal = {Huan jing ke xue= Huanjing kexue},
volume = {40},
number = {7},
pages = {3179-3185},
doi = {10.13227/j.hjkx.201811020},
pmid = {31854716},
issn = {0250-3301},
abstract = {In a cyclic alternating O/A operation mode, phosphorus accumulating organisms (PAOs) can undertake phosphate removal and enrichment as the main process in wastewater treatment plants. The effects of the concentration of carbon sources during the aerobic stage on phosphate removal and enrichment performance of PAO biofilms, and the microbial population structure in the biofilms, were investigated. The results showed that the aerobic COD concentration decreased from 200 mg·L-1 to 0 mg·L-1, the phosphorus uptake rate improved by 1.29 times, the phosphorus concentration in effluent stabilized below 0.5 mg·L-1, the phosphorus release rate increased by 3.56 times, and the phosphate concentration in the circulating solution increased from 27.125 mg·L-1 to 55.91 mg·L-1. With respect to the change in microbial communities, the identification showed that the abundance of Proteobacteria increased by approximately two times, and the enrichment effects of Rhodocyclaceae and Anaerolineaceae increased by 2.28 and 5 times, respectively. Reducing the concentration of the carbon source in the aerobic section was beneficial to the screening and enrichment of PAOs, strengthening the removal of phosphate in the aerobic section and the release of phosphate in the anaerobic section. This resulted in an enriched phosphate solution. These observations provide a theoretical basis for future urban sewage treatment plants seeking to reduce their carbon demand.},
}
@article {pmid31853764,
year = {2019},
author = {Tahmasebi, H and Dehbashi, S and Jahantigh, M and Arabestani, MR},
title = {Relationship between biofilm gene expression with antimicrobial resistance pattern and clinical specimen type based on sequence types (STs) of methicillin-resistant S. aureus.},
journal = {Molecular biology reports},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11033-019-05233-4},
pmid = {31853764},
issn = {1573-4978},
support = {9510145962//Vice chancellor for research, Hamadan university of Medical Science/ ; },
abstract = {The ica genes in methicillin-resistant Staphylococcus aureus (MRSA) play an important role in biofilm formation. The aim of this study is to define effect of antibiotic resistance and clinical specimens to the expression of ica genes based on their sequence types (STs) and clonal complex (CC). One-hundred (100) S. aureus strain were collected from two teaching therapeutic centers in Hamedan, Iran. Then, the PCR, qPCR, and MLST were used to characterize strains. The results indicated that 29 (29%), 15 (15%), and 5 (5%) strain were strong, mediate, weak biofilm producer, respectively, and the icaA (17%) and icaC (14%) genes were the most abundant. However, two unique STs (3667, 491) in Iran were reported and ST30 and ST11 were the most abundant STs and CC30 and CC5 were observed among MRSA and MSSA strains. High activity in ica locus was observed among strains collected from wound and catheter strains. Also, expression level of icaA gene increased in all strains except ST30 and ST491. Moreover, the highest expression level was observed in CC1, CC7, and CC11. Likewise, activity of the icaC gene was only observed in CC5. Furthermore, the expression of all ica genes in CC5 was significantly correlated with the type of biofilm and the clinical sample. In this study demonstrated that the frequency distribution of STs and CCs in different strains of MRSA was higher than methicillin-sensitive strains. Also, the type of clinical specimen and expression of ica genes played an important role in this abundance.},
}
@article {pmid31853190,
year = {2019},
author = {Amin, M and Navidifar, T and Shooshtari, FS and Rashno, M and Savari, M and Jahangirmehr, F and Arshadi, M},
title = {Association Between Biofilm Formation, Structure, and the Expression Levels of Genes Related to biofilm formation and Biofilm-Specific Resistance of Acinetobacter baumannii Strains Isolated from Burn Infection in Ahvaz, Iran.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {3867-3881},
pmid = {31853190},
issn = {1178-6973},
abstract = {Background: The ability of biofilm formation is an effective way for Acinetobacter baumannii survival from stressed conditions. This present study was aimed to evaluate the association between biofilm formation, structure, the expression levels of genes related to biofilm formation and biofilm-specific resistance of A. baumannii strains isolated from burn infections in Ahvaz, Iran.<br><br>Methods: In this study, we assessed the antibiotic susceptibilities, ERIC-PCR typing, capacity of biofilm formation and biofilm structure of 64 A. baumannii isolates collected from burn infections. The distribution and the expression levels of genes involved in the biofilm formation including bap, ompA, abaI, pgaA and csuE were assessed by PCR and real-time PCR, respectively.<br><br>Results: We classified A. baumannii isolates in 14 clonal types of ERIC-PCR. Most A. baumannii isolates were resistant to all antibiotics tested except to tigecycline and colistin and had the biofilm formation capability but with different capacities. There was a significant inverse relationship between resistance to antibiotic agents and biofilm formation. The biofilm matrix of 50 strains consisted of polysaccharides together with DNA or proteins. The genes involved in the biofilm formation were detected in both biofilm-forming and non-biofilm forming; however, the expression levels of these genes were higher in biofilm producers compared with non-producers.<br><br>Conclusion: The biofilm cells exhibited dramatically decreased susceptibility to antibiotic agents; hence, they have great significance for public health. Therefore, the determination of antibiotic susceptibilities in biofilm and planktonic mode, molecular typing, and capacity of biofilm formation in clinical setting is essential.},
}
@article {pmid31851822,
year = {2019},
author = {Condren, AR and Kahl, LJ and Boelter, G and Kritikos, G and Banzhaf, M and Dietrich, LE and Sanchez, LM},
title = {Biofilm inhibitor taurolithocholic acid alters colony morphology, specialized metabolism, and virulence of Pseudomonas aeruginosa.},
journal = {ACS infectious diseases},
volume = {},
number = {},
pages = {},
doi = {10.1021/acsinfecdis.9b00424},
pmid = {31851822},
issn = {2373-8227},
abstract = {Biofilm inhibition by exogenous molecules has been an attractive strategy for the development of novel therapeutics. We investigated the biofilm inhibitor taurolithocholic acid (TLCA) and its effects on the specialized metabolism, virulence and biofilm formation of the clinically relevant bacterium Pseudomonas aeruginosa strain PA14. Our study shows that TLCA alters specialized metabolism, thereby affecting P. aeruginosa colony biofilm physiology. We observed an upregulation of metabolites correlated to virulence such as the siderophore pyochelin. A wax moth virulence assay confirmed that treatment with TLCA increases virulence of P. aeruginosa. Based on our results, we believe that future endeavors to identify biofilm inhibitors must consider how a putative lead is altering the specialized metabolism of a bacterial community to prevent pathogens from entering a highly virulent state.},
}
@article {pmid31850313,
year = {2019},
author = {Verderosa, AD and Totsika, M and Fairfull-Smith, KE},
title = {Bacterial Biofilm Eradication Agents: A Current Review.},
journal = {Frontiers in chemistry},
volume = {7},
number = {},
pages = {824},
pmid = {31850313},
issn = {2296-2646},
abstract = {Most free-living bacteria can attach to surfaces and aggregate to grow into multicellular communities encased in extracellular polymeric substances called biofilms. Biofilms are recalcitrant to antibiotic therapy and a major cause of persistent and recurrent infections by clinically important pathogens worldwide (e.g., Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus). Currently, most biofilm remediation strategies involve the development of biofilm-inhibition agents, aimed at preventing the early stages of biofilm formation, or biofilm-dispersal agents, aimed at disrupting the biofilm cell community. While both strategies offer some clinical promise, neither represents a direct treatment and eradication strategy for established biofilms. Consequently, the discovery and development of biofilm eradication agents as comprehensive, stand-alone biofilm treatment options has become a fundamental area of research. Here we review our current understanding of biofilm antibiotic tolerance mechanisms and provide an overview of biofilm remediation strategies, focusing primarily on the most promising biofilm eradication agents and approaches. Many of these offer exciting prospects for the future of biofilm therapeutics for a large number of infections that are currently refractory to conventional antibiotics.},
}
@article {pmid31849905,
year = {2019},
author = {Wu, Y and Wang, R and Xu, M and Liu, Y and Zhu, X and Qiu, J and Liu, Q and He, P and Li, Q},
title = {A Novel Polysaccharide Depolymerase Encoded by the Phage SH-KP152226 Confers Specific Activity Against Multidrug-Resistant Klebsiella pneumoniae via Biofilm Degradation.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2768},
pmid = {31849905},
issn = {1664-302X},
abstract = {The increasing prevalence of infections caused by multidrug-resistant Klebsiella pneumoniae necessitates the development of alternative therapies. Here, we isolated, characterized, and sequenced a K. pneumoniae bacteriophage (SH-KP152226) that specifically infects and lyses K. pneumoniae capsular type K47. The phage SH-KP152226 contains a genome of 41,420 bp that encodes 48 predicted proteins. Among these proteins, Dep42, the gene product of ORF42, is a putative tail fiber protein and hypothetically possesses depolymerase activity. We demonstrated that recombinant Dep42 showed specific enzymatic activities in the depolymerization of the K47 capsule of K. pneumoniae and was able to significantly inhibit biofilm formation and/or degrade formed biofilms. We also showed that Dep42 could enhance polymyxin activity against K. pneumoniae biofilms when used in combination with antibiotics. These results suggest that combination of the identified novel depolymerase Dep42, encoded by the phage SH-KP152226, with antibiotics may represent a promising strategy to combat infections caused by drug-resistant and biofilm-forming K. pneumoniae.},
}
@article {pmid31849901,
year = {2019},
author = {Zimmermann, S and Klinger-Strobel, M and Bohnert, JA and Wendler, S and Rödel, J and Pletz, MW and Löffler, B and Tuchscherr, L},
title = {Clinically Approved Drugs Inhibit the Staphylococcus aureus Multidrug NorA Efflux Pump and Reduce Biofilm Formation.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2762},
pmid = {31849901},
issn = {1664-302X},
abstract = {Staphylococcus aureus has acquired resistance to antibiotics since their first use. The S. aureus protein NorA, an efflux pump belonging to the major facilitator superfamily (MFS), contributes to resistance to fluoroquinolones (e.g., ciprofloxacin), biocides, dyes, quaternary ammonium compounds, and antiseptics. Different compounds have been identified as potential efflux pump inhibitors (EPIs) of NorA that result in increased intracellular concentration of antibiotics, restoring their antibacterial activity and cell susceptibility. However, none of the currently known EPIs have been approved for clinical use, probably due to their toxicity profiles. In the present study, we screened approved drugs for possible efflux pump inhibition. By screening a compound library of approximately 1200 different drugs, we identified nilotinib, a tyrosine kinase inhibitor, as showing the best efflux pump inhibitory activity, with a fractional inhibitory concentration index of 0.1875, indicating synergism with ciprofloxacin, and a minimum effective concentration as low as 0.195 μM. Moreover, at 0.39 μM, nilotinib, in combination with 8 μg/mL of ciprofloxacin, led to a significant reduction in biofilm formation and preformed mature biofilms. This is the first description of an approved drug that can be used as an efflux pump inhibitor and to reduce biofilms formation at clinically achievable concentrations.},
}
@article {pmid31849660,
year = {2019},
author = {Scriboni, AB and Couto, VM and Ribeiro, LNM and Freires, IA and Groppo, FC and de Paula, E and Franz-Montan, M and Cogo-Müller, K},
title = {Fusogenic Liposomes Increase the Antimicrobial Activity of Vancomycin Against Staphylococcus aureus Biofilm.},
journal = {Frontiers in pharmacology},
volume = {10},
number = {},
pages = {1401},
pmid = {31849660},
issn = {1663-9812},
abstract = {Objective: The aim of the present study was to encapsulate vancomycin in different liposomal formulations and compare the in vitro antimicrobial activity against Staphylococcus aureus biofilms. Methods: Large unilamellar vesicles of conventional (LUV VAN), fusogenic (LUVfuso VAN), and cationic (LUVcat VAN) liposomes encapsulating VAN were characterized in terms of size, polydispersity index, zeta potential, morphology, encapsulation efficiency (%EE) and in vitro release kinetics. The formulations were tested for their Minimum Inhibitory Concentration (MIC) and inhibitory activity on biofilm formation and viability, using methicillin-susceptible S. aureus ATCC 29213 and methicillin-resistant S. aureus ATCC 43300 strains. Key Findings: LUV VAN showed better %EE (32.5%) and sustained release than LUVfuso VAN, LUVcat VAN, and free VAN. The formulations were stable over 180 days at 4°C, except for LUV VAN, which was stable up to 120 days. The MIC values for liposomal formulations and free VAN ranged from 0.78 to 1.56 µg/ml against both tested strains, with no difference in the inhibition of biofilm formation as compared to free VAN. However, when treating mature biofilm, encapsulated LUVfuso VAN increased the antimicrobial efficacy as compared to the other liposomal formulations and to free VAN, demonstrating a better ability to penetrate the biofilm. Conclusion: Vancomycin encapsulated in fusogenic liposomes demonstrated enhanced antimicrobial activity against mature S. aureus biofilms.},
}
@article {pmid31848281,
year = {2019},
author = {Fraikin, N and Rousseau, CJ and Goeders, N and Van Melderen, L},
title = {Reassessing the Role of the Type II MqsRA Toxin-Antitoxin System in Stress Response and Biofilm Formation: mqsA Is Transcriptionally Uncoupled from mqsR.},
journal = {mBio},
volume = {10},
number = {6},
pages = {},
pmid = {31848281},
issn = {2150-7511},
abstract = {Toxin-antitoxin (TA) systems are broadly distributed modules whose biological roles remain mostly unknown. The mqsRA system is a noncanonical TA system in which the toxin and antitoxins genes are organized in operon but with the particularity that the toxin gene precedes that of the antitoxin. This system was shown to regulate global processes such as resistance to bile salts, motility, and biofilm formation. In addition, the MqsA antitoxin was shown to be a master regulator that represses the transcription of the csgD, cspD, and rpoS global regulator genes, thereby displaying a pleiotropic regulatory role. Here, we identified two promoters located in the toxin sequence driving the constitutive expression of mqsA, allowing thereby excess production of the MqsA antitoxin compared to the MqsR toxin. Our results show that both antitoxin-specific and operon promoters are not regulated by stresses such as amino acid starvation, oxidative shock, or bile salts. Moreover, we show that the MqsA antitoxin is not a global regulator as suggested, since the expression of csgD, cspD and rpoS is similar in wild-type and ΔmqsRA mutant strains. Moreover, these two strains behave similarly in terms of biofilm formation and sensitivity to oxidative stress or bile salts.IMPORTANCE There is growing controversy regarding the role of chromosomal toxin-antitoxin systems in bacterial physiology. mqsRA is a peculiar toxin-antitoxin system, as the gene encoding the toxin precedes that of the antitoxin. This system was previously shown to play a role in stress response and biofilm formation. In this work, we identified two promoters specifically driving the constitutive expression of the antitoxin, thereby decoupling the expression of antitoxin from the toxin. We also showed that mqsRA contributes neither to the regulation of biofilm formation nor to the sensitivity to oxidative stress and bile salts. Finally, we were unable to confirm that the MqsA antitoxin is a global regulator. Altogether, our data are ruling out the involvement of the mqsRA system in Escherichia coli regulatory networks.},
}
@article {pmid31847837,
year = {2019},
author = {Shrestha, R and Khanal, S and Poudel, P and Khadayat, K and Ghaju, S and Bhandari, A and Lekhak, S and Pant, ND and Sharma, M and Marasini, BP},
title = {Extended spectrum β-lactamase producing uropathogenic Escherichia coli and the correlation of biofilm with antibiotics resistance in Nepal.},
journal = {Annals of clinical microbiology and antimicrobials},
volume = {18},
number = {1},
pages = {42},
pmid = {31847837},
issn = {1476-0711},
abstract = {BACKGROUND: Urinary tract infection (UTI) is one of the frequently diagnosed infectious diseases which is caused mainly by Escherichia coli. E. coli confers resistance against the two major classes of antibiotics due to the production of extended spectrum β-lactamase enzymes (ESBL), biofilm, etc. Biofilm produced by uropathogenic E. coli (UPEC) protects from host immune system and prevent entry of antimicrobial compounds. The main objective of this cross-sectional study was to determine the correlation of biofilm production and antibiotic resistance as well as to characterize the pgaA and pgaC genes responsible for biofilm formation among uropathogenic ESBL producing E. coli.<br><br>METHODS: A total of 1977 mid-stream urine samples were examined and cultured for bacterial strain identification. ESBL was detected by combined disc method following CLSI whereas biofilm formation was analyzed by semi-quantitative method. Furthermore, the pgaA and pgaC genes responsible for biofilm formation in UPEC were detected by multiplex PCR. All the statistical analyses were done via IBM SPSS Statistics 21 where Pearson's correlation test were used to determine correlation (-1 ≥ r ≤ 1).<br><br>RESULTS: E. coli was the predominant causative agent, which accounted 159 (59.3%) of the Gram-negative bacteria, where 81 (50.9%) E. coli strains were found to be ESBL producers. In addition, 86 (54.1%) E. coli strains were found to be biofilm producers. Both the pgaA and pgaC genes were detected in 45 (93.7%) the UPEC isolates, which were both biofilm and ESBL producers. Moreover, there was a positive correlation between biofilm and ESBL production.<br><br>CONCLUSION: The analyses presented weak positive correlation between biofilm and ESBL production in which biofilm producing UPEC harbors both pgaA and pgaC genes responsible for biofilm formation.},
}
@article {pmid31847713,
year = {2019},
author = {Jhanji, R and Bhati, V and Singh, A and Kumar, A},
title = {Phytomolecules against bacterial biofilm and efflux pump: An In silico and In vitro study.},
journal = {Journal of biomolecular structure &amp; dynamics},
volume = {},
number = {},
pages = {1-12},
doi = {10.1080/07391102.2019.1704884},
pmid = {31847713},
issn = {1538-0254},
abstract = {Antibiotic resistance is a global threat whose incidences are increasing day by day worldwide. Thus, there is a need for new chemical entities (NCEs) or exploration of existing molecules against these types of infections. In the current investigation, we have tested the inhibitory potential of four different phytomolecules (berberine, gallic acid, piperine, and rutin) against bacterial biofilm and efflux pumps by using in-silico and in-vitro techniques. The phytomolecules (berberine, piperine, and rutin) except gallic acid have shown good interaction towards biofilm and efflux pump proteins. Further, In-vitro studies have also shown the good inhibitory effect of tested phytomolecules (berberine, rutin, and piperine) against bacterial biofilm formation and efflux pumps. In conclusion, berberine, piperine, and rutin could be the promising antibacterial candidates, particularly against resistant bacterial strains.},
}
@article {pmid31847295,
year = {2019},
author = {Fratianni, F and Cozzolino, A and De Feo, V and Coppola, R and Ombra, MN and Nazzaro, F},
title = {Polyphenols, Antioxidant, Antibacterial, and Biofilm Inhibitory Activities of Peel and Pulp of Citrus medica L., Citrus bergamia, and Citrus medica cv. Salò Cultivated in Southern Italy.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {24},
pages = {},
doi = {10.3390/molecules24244577},
pmid = {31847295},
issn = {1420-3049},
support = {PON4a2//Italian MIUR Be &amp; Save Project 2007-2013/ ; Project CALABRIA SALUS PSR 2007-2013//Regione Calabria/ ; },
abstract = {The aim of this paper was to study the polyphenols of peel and pulp of three Citrus taxa-Citrus medica, Citrus bergamia, and Citrus medica cv. Salò-cultivated in the Cosenza province, Southern Italy, and to evaluate their antioxidant and antibacterial activity, performed against Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Staphylococcus aureus, and Pectobacterium carotovorum. Furthermore, we assessed the inhibitory effect of the extracts on bacterial capacity to form biofilm, and on the metabolic activity of the cells present therein. The results indicated that such extracts could find new potential applications in the field of natural antioxidant and anti-bacterial agents in pharmaceutics, agriculture, and food fields.},
}
@article {pmid31847278,
year = {2019},
author = {Lamas, A and Regal, P and Vázquez, B and Cepeda, A and Franco, CM},
title = {Short Chain Fatty Acids Commonly Produced by Gut Microbiota Influence Salmonellaenterica Motility, Biofilm Formation, and Gene Expression.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/antibiotics8040265},
pmid = {31847278},
issn = {2079-6382},
abstract = {Short chain fatty acids (SCFAs) are commonly produced by healthy gut microbiota and they have a protective role against enteric pathogens. SCFAs also have direct antimicrobial activity against bacterial pathogens by diffusion across the bacterial membrane and reduction of intracellular pH. Due to this antimicrobial activity, SCFAs have promising applications in human health and food safety. In this study, the minimum inhibitory concentrations (MICs) of four SCFAs (acetic acid, butyric acid, propionic acid, and valeric acid) in Salmonella strains isolated from poultry were determined. The effect of subinhibitory concentrations of SCFAs in Salmonella biofilm formation, motility, and gene expression was also evaluated. Butyric acid, propionic acid, and valeric acid showed a MIC of 3750 µg/mL in all strains tested, while the MIC of acetic acid was between 1875 and 3750 µg/mL. Subinhibitory concentrations of SCFAs significantly (p< 0.05) reduced the motility of all Salmonella strains, especially in the presence of acetic acid. Biofilm formation was also significantly (p < 0.05) lower in the presence of SCFAs in some of the Salmonella strains. Salmonella strain. Salmonella Typhimurium T7 showed significant (p < 0.05) upregulation of important virulence genes, such as invA and hilA, especially in the presence of butyric acid. Therefore, SCFAs are promising substances for the inhibition of the growth of foodborne pathogens. However, it is important to avoid the use of subinhibitory concentrations that could increase the virulence of foodborne pathogen Salmonella.},
}
@article {pmid31846875,
year = {2019},
author = {Hassard, F and Biddle, J and Cartmell, E and Coulon, F and Stephenson, T},
title = {Biosolids recycling impact on biofilm extracellular enzyme activity and performance of hybrid rotating biological reactors.},
journal = {The Science of the total environment},
volume = {706},
number = {},
pages = {135865},
doi = {10.1016/j.scitotenv.2019.135865},
pmid = {31846875},
issn = {1879-1026},
abstract = {Biological processes for wastewater treatment is limited by extracellular enzyme activity (EEA) of the biofilm on polymeric substrates. The efficiency of biodegradation / biosorption mechanisms causing EEA and organic load removal in biofilms remains unknown. Our hypothesis was that the limiting step of biological process can be overcome by biostimulation and/or bioaugmentation of the return sludge in hybrid biofilm reactors, which leads to competition between suspended and attached bacteria and lower effective substrate to microrganism ratio. Therefore, we considered more active biosolids to perform best at enhancing reactor removal rate. To test this, the efficacy of recycling distinct bio-solids types considered to have different bacterial activity such as final effluent (FE), humus solids (HS) and recycle activated sludge (RAS) on performance improvements of rotating biofilm reactors (RBRs). These bio-solids were investigated under high organic loading rates (OLR) and solids loading rates (SLR) using pilot scale reactors receiving real municipal wastewaters. Controlled overloading of RBRs revealed that EEA improved with increasing OLR/SLR. High SLR (>3.3 kg Total Suspended Solids m-2 d-1) delayed and decreased the reduction of organic and inorganic removal rates in the biological processes which commonly occurs under high OLRs. This effect was more pronounced in the highest activity solids (RAS > HS > FE) suggesting the activity and function of bio-solids was critical to improve performance of RBRs. High OLR and SLR induced efficient denitrification and organics removal within the biofilm reactor at residence times of <5 min. Recycling active solids permitted EEA despite overloading which was critical to the performance of the RBRs.},
}
@article {pmid31846135,
year = {2019},
author = {Ben Lagha, A and LeBel, G and Grenier, D},
title = {Tart cherry (Prunus cerasus L.) fractions inhibit biofilm formation and adherence properties of oral pathogens and enhance oral epithelial barrier function.},
journal = {Phytotherapy research : PTR},
volume = {},
number = {},
pages = {},
doi = {10.1002/ptr.6574},
pmid = {31846135},
issn = {1099-1573},
support = {2017-2018//Cherry Marketing Institute/ ; },
abstract = {Dental caries, candidiasis, and periodontal disease are the most common oral infections affecting a wide range of the population worldwide. The present study investigated the effects of two tart cherry (Prunus cerasus L.) fractions on important oral pathogens, including Candida albicans, Streptococcus mutans, and Fusobacterium nucleatum, as well as on the barrier function of oral epithelial cells. Procyanidins and quercetin and its derivatives were the most important constituents found in the tart cherry fractions. Although the fractions showed poor antimicrobial activity, they inhibited biofilm formation by the three oral pathogens in a dose-dependent manner. The tart cherry fractions also attenuated the adherence of C. albicans and S. mutans to a hydroxylapatite surface as well as the adherence of F. nucleatum to oral epithelial cells. Treating oral epithelial cells with the tart cherry fractions significantly enhanced the barrier function as determined by monitoring the transepithelial electrical resistance. In conclusion, this study showed that the tart cherry fractions and their bioactive constituents could be promising antiplaque compounds by targeting biofilm formation and adherence properties of oral pathogens. Furthermore, its property of increasing the epithelial barrier function may protect against microbial invasion of the underlying connective tissue.},
}
@article {pmid31842619,
year = {2019},
author = {Rocca, DM and Aiassa, V and Zoppi, A and Silvero C, MJ and Becerra, MC},
title = {NANOSTRUCTURED GOLD COATING FOR PREVENTION OF BIOFILM DEVELOPMENT IN MEDICAL DEVICES.},
journal = {Journal of endourology},
volume = {},
number = {},
pages = {},
doi = {10.1089/end.2019.0686},
pmid = {31842619},
issn = {1557-900X},
abstract = {Bacterial biofilms on medical devices (MDs) can cause deadly infections due to their resistance to antibiotics. Technology to prevent this kind of complication is urgently needed because they impact not only patients' lives but also hospital budgets. In this paper, the creation and testing of an easy to produce antibiofilm (more precisely antibiofouling) coating are described for the first time. This coating can be applied to catheters, prostheses and other plastic pieces, even after they have been manufactured. Rapid and eco-friendly synthesis of nanostructured gold coating was done in situ in just 15 minutes. Complete characterization and microbiological analysis of its antibiofouling capacity are presented. The coating prevents biofilm formation of pathogenic clinical isolates and ATCC strains on medical devices, possibly due to its complex nanostructured gold surface. If the next generation of medical devices is coated with this kind of antibiofouling technology, biofilm-related infections could be dramatically reduced.},
}
@article {pmid31842508,
year = {2019},
author = {Park, SC and Lee, MY and Kim, JY and Kim, H and Jung, M and Shin, MK and Lee, WK and Cheong, GW and Lee, JR and Jang, MK},
title = {Anti-Biofilm Effects of Synthetic Antimicrobial Peptides Against Drug-Resistant Pseudomonas aeruginosa and Staphylococcus aureus Planktonic Cells and Biofilm.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {24},
pages = {},
doi = {10.3390/molecules24244560},
pmid = {31842508},
issn = {1420-3049},
support = {NRF-2016R1D1A3A03918533 &amp; NRF-2019R1I1A3A01062547//National Research Foundation of Korea/ ; },
abstract = {Biofilm-associated infections are difficult to manage or treat as biofilms or biofilm-embedded bacteria are difficult to eradicate. Antimicrobial peptides have gained increasing attention as a possible alternative to conventional drugs to combat drug-resistant microorganisms because they inhibit the growth of planktonic bacteria by disrupting the cytoplasmic membrane. The current study investigated the effects of synthetic peptides (PS1-2, PS1-5, and PS1-6) and conventional antibiotics on the growth, biofilm formation, and biofilm reduction of drug-resistant Pseudomonas aeruginosa and Staphylococcus aureus. The effects of PS1-2, PS1-5, and PS1-6 were also tested in vivo using a mouse model. All peptides inhibited planktonic cell growth and biofilm formation in a dose-dependent manner. They also reduced preformed biofilm masses by removing the carbohydrates, extracellular DNA, and lipids that comprised extracellular polymeric substances (EPSs) but did not affect proteins. In vivo, PS1-2 showed the greatest efficacy against preformed biofilms with no cytotoxicity. Our findings indicate that the PS1-2 peptide has potential as a next-generation therapeutic drug to overcome multidrug resistance and to regulate inflammatory response in biofilm-associated infections.},
}
@article {pmid31841686,
year = {2019},
author = {Afrasiabi, S and Pourhajibagher, M and Chiniforush, N and Aminian, M and Bahador, A},
title = {Anti-biofilm and anti-metabolic effects of antimicrobial photodynamic therapy using chlorophyllin-phycocyanin mixture against Streptococcus mutans in experimental biofilm caries model on enamel slabs.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {101620},
doi = {10.1016/j.pdpdt.2019.101620},
pmid = {31841686},
issn = {1873-1597},
abstract = {BACKGROUND: Partial selective removal of dental caries is a suitable manner to treat deep carious lesions in vital teeth with asymptomatic pulps. Antimicrobial photodynamic therapy (aPDT) was proposed as a promising ancillary approach for reduction of the residual bacteria from the cavity. Therefore, the focus of this study was to investigate the influence of aPDT using diode laser (DL) plus PhotoActive+ (chlorophyllin-phycocyanin mixture [CHL-PC]) as photosensitizer (PS) on metabolic activity and the reduction in the number of living bacteria within the preformed biofilm caries model on enamel slabs of Streptococcus mutans.<br><br>MATERIALS AND METHODS: The lethal and sub-significant inhibitory (SSI) potential of aPDT using CHL-PC and 635 nm DL against experimental biofilm caries model on enamel slabs and metabolic activity of S. mutans was analyzed using crystal violet and XTT reduction assays, respectively. Intracellular ROS formation by DCFH-DA assay was measured in CHL-PC mediated aPDT treated bacterial samples. Tooth discoloration and cell cytotoxicity of CHL-PC were assessed in the CIEL*a*b* color space and neutral red assay, respectively.<br><br>RESULTS: In this study aPDT at a maximum concentration level of CHL-PC (5000 μg/mL) with 3 minutes DL irradiation time (103.12 J/cm2) reduced the ex-vivo cariogenic biofilm of S. mutans by 36.93% (P < 0.05). Although chlorhexidine (CHX) had an anti-biofilm effect about 1.7 fold compared to CHL-PC mediated aPDT, this difference was not significant (36.93 in comparison to 63.05%; P > 0.05). CHL-PC mediated aPDT demonstrated a significant reduction in bacterial metabolic activity, with rates of 77% at a SSI dose (using 156 μg/mL of CHL-PC and 3 minutes DL irradiation time with the energy density of 103.12 J/cm2). The treated bacterial cells exhibited significant (P < 0.05) increment in the ROS generation. The least color change (ΔE) was found using CHL-PC at a concentration of 156 μg/mL (ΔE = 2.74). CHL-PC in different concentrations showed no significant reduction in human gingival fibroblasts (HGFs) cell survival (P > 0.05).<br><br>CONCLUSION: CHL-PC mediated aPDT not only reduces the number of living bacteria within the biofilms of S. mutans in an experimental biofilm caries model on enamel slabs but also its influences microbial virulence by reducing the metabolic activity of the S. mutants.},
}
@article {pmid31839202,
year = {2019},
author = {Chen, H and Tang, Y and Weir, MD and Gao, J and Imazato, S and Oates, TW and Lei, L and Wang, S and Hu, T and Xu, HHK},
title = {Effects of S. mutans gene-modification and antibacterial monomer dimethylaminohexadecyl methacrylate on biofilm growth and acid production.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.dental.2019.12.001},
pmid = {31839202},
issn = {1879-0097},
abstract = {OBJECTIVES: Antibacterial quaternary ammonium monomers (QAMs) are used in resins. The rnc gene in Streptococcus mutans (S. mutans) plays a key role in resisting antibiotics. The objectives of this study were to investigate for the first time: (1) the effects of rnc deletion on S. mutans biofilms and acid production; (2) the combined effects of rnc deletion with dimethylaminohexadecyl methacrylate (DMAHDM) on biofilm-inhibition efficacy.<br><br>METHODS: Parent S. mutans strain UA159 (ATCC 700610) and the rnc-deleted S. mutans were used. Bacterial growth, minimum inhibitory concentration (MIC), and minimal bactericidal concentration (MBC) were measured to analyze the bacterial susceptibility of the parent and rnc-deleted S. mutans against DMAHDM, with the gold-standard chlorhexidine (CHX) as control. Biofilm biomass, polysaccharide and lactic acid production were measured.<br><br>RESULTS: The drug-susceptibility of the rnc-deleted S. mutans to DMAHDM or CHX was 2-fold higher than parent S. mutans. The drug-susceptibility did not increase after 10 passages (p < 0.05). Deleting the rnc gene increased the biofilm susceptibility to DMAHDM or CHX by 2-fold. The rnc-deletion in S. mutans reduced biofilm biomass, polysaccharide and lactic acid production, even at no drugs. DMAHDM was nearly 40 % more potent than the gold-standard CHX. The combination of rnc deletion+DMAHDM treatment achieved the greatest reduction in biofilm biomass, polysaccharide synthesis, and lactic acid production.<br><br>SIGNIFICANCE: Gene modification by deleting the rnc in S. mutans reduced the biofilm growth and acid production, and the rnc deletion+DMAHDM method showed the greatest biofilm-inhibition efficacy, for the first time. The dual strategy of antibacterial monomer+bacterial gene modification shows great potential to control biofilms and inhibit caries.},
}
@article {pmid31838704,
year = {2019},
author = {Voisin, J and Cournoyer, B and Marjolet, L and Vienney, A and Mermillod-Blondin, F},
title = {Ecological assessment of groundwater ecosystems disturbed by recharge systems using organic matter quality, biofilm characteristics, and bacterial diversity.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
doi = {10.1007/s11356-019-06971-5},
pmid = {31838704},
issn = {1614-7499},
support = {ANR-16-CE32-0006 FROG//Agence Nationale de la Recherche/ ; EST 2016/1/120//Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail/ ; PhD grant//Région Auvergne-Rhône-Alpes/ ; OTHU//Agence de l'Eau Rhône Méditerranée Corse/ ; OTHU//Métropole de Lyon/ ; },
abstract = {Recharge of aquifers by urban stormwater may trigger significant ecological changes that can be detrimental to the biodiversity and functioning of groundwater ecosystems. Here, the effects of aquifer recharge (AR) on three levels of parameters were investigated: dissolved organic carbon (DOC) quantity and quality, global biofilm characteristics, and diversity changes of bacterial communities. As DOC enrichment by AR can be mitigated by vadose zone (VZ) thickness, three AR sites with thin VZ (< 3 m) and three sites with thick VZ (> 10 m) were selected. For each AR site, clay beads were incubated over a 10-day-long rainy period through wells in recharged and non-recharged groundwaters. Total proteins, dehydrogenase, and hydrolytic activities were monitored from clay beads to assess biofilm development. Bacterial richness on beads was estimated by 16S rRNA-based metabarcoding. AR was found to significantly increase DOC and biodegradable DOC (BDOC) concentrations, biofilm development, and bacterial richness especially in sites with thin VZ. VZ thickness was inversely related to microbial growth indicators and bacterial richness in groundwater, through a control of DOC availability. The proportion of Bacteroidetes 16S rRNA gene reads was higher in recharged groundwater than in non-recharged groundwater, suggesting that this phylum could be used as an indicator of DOC enrichment associated with AR. Quantitative PCR assays for Bacteroides DNA confirmed these trends and showed an enrichment of this bacterial group in DOC-rich aquifer waters. The positive linear relationships between BDOC concentrations and biofilm variables highlighted a strong C-limitation of groundwater impacting bacterial species sorting and activity.},
}
@article {pmid31835971,
year = {2019},
author = {Magalhães, AP and Jorge, P and Pereira, MO},
title = {Pseudomonas aeruginosa and Staphylococcus aureus communication in biofilm infections: insights through network and database construction.},
journal = {Critical reviews in microbiology},
volume = {},
number = {},
pages = {1-17},
doi = {10.1080/1040841X.2019.1700209},
pmid = {31835971},
issn = {1549-7828},
abstract = {The polymicrobial nature of most infections is often characterized by complex biofilm communities, where pathogen interactions promote infection progression and severity. Quorum-sensing, the major regulator of virulence and inter-species communication, is a promising target for new anti-infective strategies. This study aimed at collecting and analysing experimental information on the molecular basis of Pseudomonas aeruginosa and Staphylococcus aureus interactions in biofilms. Data were systematically annotated from relevant full-text papers optimally retrieved from PubMed, reconstructed as networks and integrated with specialized databases to identify promising antimicrobial targets. Network analysis revealed key entities regulating P. aeruginosa/S. aureus interactions, for instance the PqsABCDE/PqsR quorum-sensing system, which affects S. aureus growth and biofilm formation. By identifying the most reported P. aeruginosa virulence factors affecting S. aureus, for example, HQNO and siderophores, a list of experimentally validated agents affecting those factors, ranging from synthetic drugs to natural plant extracts, was constructed. The complex experimental data on P. aeruginosa/S. aureus interactions were for the first time systematically organized and made publically available in the new Inter-Species CrossTalk Database (www.ceb.uminho.pt/ISCTD).},
}
@article {pmid31835833,
year = {2019},
author = {Felix Gomez, GG and Lippert, F and Ando, M and Zandona, AF and Eckert, GJ and Gregory, RL},
title = {Photoinhibition of Streptococcus mutans Biofilm-Induced Lesions in Human Dentin by Violet-Blue Light.},
journal = {Dentistry journal},
volume = {7},
number = {4},
pages = {},
doi = {10.3390/dj7040113},
pmid = {31835833},
issn = {2304-6767},
abstract = {This in vitro study determined the effectiveness of violet-blue light on Streptococcus mutans (UA159) biofilm induced dentinal lesions. Biofilm was formed on human dentin specimens in a 96-well microtiter plate and incubated for 13 h in the presence of tryptic soy broth (TSB) or TSB supplemented with 1% sucrose (TSBS). Violet-blue light (405 nm) from quantitative light-induced fluorescence (QLFTM) was used to irradiate the biofilm. Supernatant liquid was removed, and the biofilm was irradiated continuously with QLF for 5 min twice daily with an interval of 6 h for 5 d, except with one treatment on the final day. Colony forming units (CFU) of the treated biofilm, changes in fluorescence (∆F; QLF-Digital BiluminatorTM), lesion depth (L), and integrated mineral loss (∆Z; both transverse microradiography) were quantified at the end of the fifth day. Statistical analysis used analysis of variance (ANOVA), testing at a 5% significance level. In the violet-blue light irradiated groups, there was a significant reduction (p < 0.05) of bacterial viability (CFU) of S. mutans with TSB and TSBS. Violet-blue light irradiation resulted in the reduction of ∆F and L of the dentinal surface with TSBS. These results indicate that violet-blue light has the capacity to reduce S. mutans cell numbers.},
}
@article {pmid31835470,
year = {2019},
author = {Di Onofrio, V and Gesuele, R and Maione, A and Liguori, G and Liguori, R and Guida, M and Nigro, R and Galdiero, E},
title = {Prevention of Pseudomonas aeruginosa Biofilm Formation on Soft Contact Lenses by Allium sativum Fermented Extract (BGE) and Cannabinol Oil Extract (CBD).},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/antibiotics8040258},
pmid = {31835470},
issn = {2079-6382},
abstract = {Two natural mixtures, Allium sativum fermented extract (BGE) and cannabinol oil extract (CBD), were assessed for their ability to inhibit and remove Pseudomonas aeruginosa biofilms on soft contact lenses in comparison to a multipurpose Soft Contact Lens-care solution present on the Italian market. Pseudomonas aeruginosa (ATCC 9027 strain) and Pseudomonas aeruginosa clinical strains isolated from ocular swabs were tested. Quantification of the biofilm was done using the microtiter plate assay and the fractional inhibitory concentration index was calculated. Both forms of Pseudomonas aeruginosa generated biofilms. BGE at minimal inhibitory concentration (MIC) showed inhibition percentages higher than 55% for both strains, and CBD inhibited biofilm formation by about 70%. The care solution at MIC inhibited biofilm formation by about 50% for both strains tested. The effect of BGE on the eradication of the microbial biofilm on soft contact lenses at MIC was 45% eradication for P. aeruginosa ATCC 9027 and 36% for P. aeruginosa clinical strain. For CBD, we observed 24% biofilm eradication for both strains. For the care solution, the eradication MICs were 43% eradication for P. aeruginosa ATCC 9027 and 41% for P. aeruginosa clinical strain. It was observed that both the test soft contact lenses solution/BGE (fractional inhibitory concentration index: 0.450) and the test soft contact lenses solution/CBD (fractional inhibitory concentration index: 0.153) combinations exhibited synergistic antibiofilm activity against most of the studied bacteria. The study showed that BGE and CBD have good effect on inhibition of biofilm formation and removal of preformed biofilms, which makes them promising agents that could be exploited to develop more effective care solutions.},
}
@article {pmid31835290,
year = {2019},
author = {De la Cruz-Claure, ML and Cèspedes-Llave, AA and Ulloa, MT and Benito-Lama, M and Domínguez-Álvarez, E and Bastida, A},
title = {Inhibition-Disruption of Candida glabrata Biofilms: Symmetrical Selenoesters as Potential Anti-Biofilm Agents.},
journal = {Microorganisms},
volume = {7},
number = {12},
pages = {},
doi = {10.3390/microorganisms7120664},
pmid = {31835290},
issn = {2076-2607},
support = {COOPB20237//Consejo Superior de Investigaciones Científicas/ ; 201780I027//Consejo Superior de Investigaciones Científicas/ ; },
abstract = {Candida glabrata is one of the most prevalent pathogenic Candida species in dental plaque on tooth surfaces. Candida biofilms exhibit an enhanced resistance against most antifungal agents. Thus, the development of alternative more potent and effective antimicrobials is required to overcome this resistance. In this study, three novel fluorinated derivatives and nine selenoester compounds were screened as novel antifungal and antibiofilm agents against C. krusei, C. parapsilosis, and C. glabrata (N = 81 dental isolates). C. glabrata strains were susceptible only to fluorinated compounds while C. krusei, C. parapsilosis, and C. glabrata were susceptible to the action of the selenoesters. The evaluated symmetrical selenoester compounds presented very good antifungal activity against all the tested C. glabrata dental isolates (1-4 μg/mL of minimum inhibitory concentration-MIC). The most active compound (Se-5) was able to inhibit and disperse C. glabrata biofilms. These results demonstrated that selenoesters may be novel and promising biocide agents against C. glabrata clinical dental isolates.},
}
@article {pmid31835130,
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 = {Erratum to &quot;Biomass segregation between biofilm and flocs improves the control of nitrite-oxidizing bacteria in mainstream partial nitritation and anammox processes&quot; [Water Res. 154 (2019) 104-116].},
journal = {Water research},
volume = {169},
number = {},
pages = {115133},
doi = {10.1016/j.watres.2019.115133},
pmid = {31835130},
issn = {1879-2448},
}
@article {pmid31834677,
year = {2019},
author = {Yang, C and Mavelli, GV and Nacharaju, P and Li, K and Cleare, LG and Nosanchuk, JD and Friedman, JM and Abuzeid, WM},
title = {Novel nitric oxide-generating platform using manuka honey as an anti-biofilm strategy in chronic rhinosinusitis.},
journal = {International forum of allergy &amp; rhinology},
volume = {},
number = {},
pages = {},
doi = {10.1002/alr.22472},
pmid = {31834677},
issn = {2042-6984},
support = {P30CA013330/BC/NCI NIH HHS/United States ; //Alpha Omega Alpha/ ; },
abstract = {BACKGROUND: Bacterial biofilms are implicated in the pathogenesis of chronic rhinosinusitis. Nitric oxide (NO) is a key immune effector with potent antimicrobial effects, but a short half-life limits achievement of therapeutic concentrations. We hypothesized that manuka honey (MH) could induce sustained reduction of nitrite to NO causing biofilm disruption and that this effect would be enhanced with the addition of a NO-releasing microparticle.<br><br>METHODS: Porous organosilica microparticles containing nitrosylated thiol groups were formulated (SNO-MP). MH was combined with serial dilutions of nitrite. NO release was evaluated using a NO analyzer. The susceptibility of 2 strains of Pseudomonas aeruginosa biofilms to these NO-releasing platforms was evaluated using confocal microscopy. Cell viability and biofilm volume were quantified. Statistical analysis was performed using the Mann-Whitney U test with SPSS software.<br><br>RESULTS: MH with nitrite generated a linear increase in NO formation. SNO-MP induced a bolus release of NO within 5 minutes, followed by a sustained plateau phase. MH with nitrite combined with SNO-MP enhanced NO release during the plateau phase. MH with nitrite reduced biofilm live cells and volume by 88.5% to 96.9% and 95.1% to 95.6%, respectively, vs control (p < 0.0001). SNO-MP reduced live cells and volume by 61.0% to 98.5% and 74.7% to 85.7%, respectively, vs control (p < 0.0001). MH with nitrite combined with SNO-MP nearly eradicated biofilm, with a 98.3% to 99.8% (log 1.8-2.6) reduction in viability and a 91.4% to 97.7% decrease in volume (p < 0.0001 vs control).<br><br>CONCLUSION: A novel platform that generates NO using MH and nitrite produces a potent anti-biofilm effect, which can be further enhanced with the addition of SNO-MP.},
}
@article {pmid31834370,
year = {2019},
author = {Ogasawara, H and Ishizuka, T and Yamaji, K and Kato, Y and Shimada, T and Ishihama, A},
title = {Regulatory Role of Pyruvate-Sensing BtsSR in Biofilm Formation by Escherichia coli K-12.},
journal = {FEMS microbiology letters},
volume = {},
number = {},
pages = {},
doi = {10.1093/femsle/fnz251},
pmid = {31834370},
issn = {1574-6968},
abstract = {Pyruvate, the key regulator in connection of a variety of metabolic pathways, influences transcription of the E. coli genome through controlling the activity of two pyruvate-sensing two-component systems (TCSs), BtsSR and PyrSR. Previously we identified the whole set of regulatory targets of PyrSR with low-affinity to pyruvate. Using gSELEX screening system, we found here that BtsSR with high-affinity to pyruvate regulates more than 100 genes including as many as 13 TF genes including the csgD gene encoding the master regulator of biofilm formation. CsgD regulates more than 20 target genes including the csg operons encoding the Curli fimbriae. In addition, we identified the csgBAC as one of the regulatory targets of BtsR, thus indicating the involvement of two pyruvate-dependent regulatory pathways of the curli formation: indirect regulation by CsgD; and direct regulation by BtsR. Based on the findings of the whole set of regulatory targets by two pyruvate-sensing BtsR and PyrR, we further propose an innovative concept that the pyruvate level-dependent regulation of different gene sets takes place through two pyruvate-sensing TCS systems, high-affinity BtsSR and low-affinity PyrSR to pyruvate.},
}
@article {pmid31833386,
year = {2019},
author = {Hassan, PA and Khider, AK},
title = {Correlation of biofilm formation and antibiotic resistance among clinical and soil isolates of Acinetobacter baumannii in Iraq.},
journal = {Acta microbiologica et immunologica Hungarica},
volume = {},
number = {},
pages = {1-10},
doi = {10.1556/030.66.2019.026},
pmid = {31833386},
issn = {1588-2640},
abstract = {Acinetobacter baumannii is an opportunistic pathogen that is reported as a major cause of nosocomial infections. The aim of this study was to investigate the biofilm formation by A. baumannii clinical and soil isolates, to display their susceptibility to 11 antibiotics and to study a possible relationship between formation of biofilm and multidrug resistance. During 8 months period, from June 2016 to January 2017, a total of 52 clinical and 22 soil isolates of A. baumannii were collected and identified through conventional phenotypic, chromo agar, biochemical tests, API 20E system, and confirmed genotypically by PCR for blaOXA-51-like gene. Antibiotic susceptibility of isolates was determined by standard disk diffusion method according to Clinical and Laboratory Standard Institute. The biofilm formation was studied using Congo red agar, test tube, and microtiter plate methods. The clinical isolates were 100% resistance to ciprofloxacin, ceftazidime, piperacillin, 96.15% to gentamicin, 96.15% to imipenem, 92.31% to meropenem, and 78.85% to amikacin. The soil A. baumannii isolates were 100% sensitive to imipenem, meropenem, and gentamicin, and 90.1% to ciprofloxacin. All A. baumannii isolates (clinical and soil) were susceptible to polymyxin B. The percentage of biofilm formation in Congo red agar, test tube, and microtiter plate assays was 10.81%, 63.51%, and 86.48%, respectively. More robust biofilm former population was mainly among non-MDR isolates. Isolates with a higher level of resistance tended to form weaker biofilms. The soil isolates exhibited less resistance to antibiotics than clinical isolates. However, the soil isolates produce stronger biofilms than clinical isolates.},
}
@article {pmid31833369,
year = {2019},
author = {Afzal, M and Saccenti, E and Madsen, M and Hansen, MB and Hyldegaard, O and Skrede, S and Martins Dos Santos, V and Norrby Teglund, A and Svensson, M},
title = {Integrated univariate, multivariate and correlation-based network analyses reveal metabolite-specific effects on bacterial growth and biofilm formation in necrotizing soft tissue infections.},
journal = {Journal of proteome research},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.jproteome.9b00565},
pmid = {31833369},
issn = {1535-3907},
abstract = {Necrotizing soft-tissue infections (NSTIs) have multiple causes, risk factors, anatomical locations, and pathogenic mechanisms. In patients with NSTI, circulating metabolites may serve as substrate having impact on bacterial adaptation at the site of infection. Metabolic signatures associated with NSTI may reveal potential be useful as diagnostic and prognostic markers, as well as novel targets for therapy. This study used untargeted metabolomics analyses of plasma from NSTI patients (n=34) and healthy (non-infected) controls (n=24) to identify the metabolic signatures and connectivity patterns among metabolites associated with NSTI. Metabolite-metabolite association networks were employed to compare the metabolic profiles of NSTI patients and non-infected surgical controls. Out of 97 metabolites detected, the abundance of 33 was significantly altered in NSTI patients. Analysis of metabolite-metabolite association networks showed a more densely connected network: specifically, 20 metabolites differentially connected between NSTI and controls. A selected set of significantly altered metabolites were tested in vitro to investigate potential influence on NSTI group A streptococcal strain growth and biofilm formation. Using chemically defined media supplemented with the selected metabolites, ornithine, ribose, urea and glucuronic acid, revealed metabolite-specific effects on both bacterial growth and biofilm formation. This study identifies for the first time an NSTI specific metabolic signature with implications for optimized diagnostics and therapies.},
}
@article {pmid31833296,
year = {2019},
author = {Han, H and Liu, ZY and Guo, JJ and Fu, XL and He, J and Guo, YD and Cai, JF},
title = {Prospects of Application of Microbial Biofilm to Estimate PMI of Corpses in Water.},
journal = {Fa yi xue za zhi},
volume = {35},
number = {5},
pages = {596-601},
doi = {10.12116/j.issn.1004-5619.2019.05.016},
pmid = {31833296},
issn = {1004-5619},
abstract = {Abstract: In forensic pathology, the estimation of postmortem interval （PMI） has always been a difficult issue, and there is still lack of effective methods to estimate PMI of corpses in water. Microbial biofilm refers to the microbial population attached to non-biological or biological surfaces by microorganisms during microbial growth, that has a three-dimensional structure, surrounded by extracellular polymers and matrix networks created by itself. A series of community succession phenomena of microorganisms occur during the occurrence and development of microbial population. The microbial community and its succession process of this kind of biofilm attached to the surface of a corpse in water may become a new basis for estimation of the PMI of corpses in water. This review elucidates on the concept, classification, research methods, and influencing factors of biofilm and analyzes its application prospects in PMI estimation of corpses in water, which would provide new ideas for the researches in this field.},
}
@article {pmid31831165,
year = {2019},
author = {Acosta, LD and Pérez-Camacho, O and Acosta, R and Escobar, DM and Gallardo, CA and Sánchez-Vargas, LO},
title = {Reduction of Candida albicans biofilm formation by coating polymethyl methacrylate denture bases with a photopolymerized film.},
journal = {The Journal of prosthetic dentistry},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.prosdent.2019.08.003},
pmid = {31831165},
issn = {1097-6841},
abstract = {STATEMENT OF PROBLEM: As Candida albicans biofilm formation is associated with severe local and systemic infections in denture-wearing patients, its prevention or reduction becomes an essential factor in the health of this population.<br><br>PURPOSE: The purpose of this in vitro study was to investigate whether 2 photopolymerized coatings of poly(acrylic acid) (PAA) and poly(itaconic acid) (PIA) can effectively reduce the adhesion of C albicans on denture base acrylic resin surfaces.<br><br>MATERIAL AND METHODS: The surface of the polymethyl methacrylate (PMMA) denture base was modified through photopolymerization of a thin film of PAA or PIA. The polymeric coatings were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), contact angle goniometry (CA), and surface roughness measurement (Ra). For biological evaluation, the coated PMMA surfaces were tested in a C albicans biofilm dynamic formation model, observed by confocal laser scanning microscopy (CLSM), and quantified by the number of colony-forming units (CFUs). The cytotoxicity of the polymeric coatings was also evaluated by using a lactic dehydrogenase-based (LDH) test. For statistical analysis, ANOVA and the nonparametric Kruskal-Wallis test were used (α=.05).<br><br>RESULTS: The PMMA resin base surfaces coated with PAA and PIA had an inhibitory effect on C albicans growth, the wettability of the coated surface, and the average roughness. The PAA and PIA coatings had no statistically significant cytotoxic effect on periodontal ligament fibroblasts.<br><br>CONCLUSIONS: PMMA acrylic resin base material was superficially modified through the incorporation of carboxylic acid groups by using PAA and PIA coatings that reduced the adherence of C albicans biofilm by 90%.},
}
@article {pmid31830915,
year = {2019},
author = {Banar, M and Emaneini, M and Beigverdi, R and Fanaei Pirlar, R and Node Farahani, N and van Leeuwen, WB and Jabalameli, F},
title = {The efficacy of lyticase and β-glucosidase enzymes on biofilm degradation of Pseudomonas aeruginosa strains with different gene profiles.},
journal = {BMC microbiology},
volume = {19},
number = {1},
pages = {291},
doi = {10.1186/s12866-019-1662-9},
pmid = {31830915},
issn = {1471-2180},
support = {93-01-30-25137//Tehran University of Medical Sciences and Health Services/ ; },
abstract = {BACKGROUND: Pseudomonas aeruginosa is a nosocomial pathogen that causes severe infections in immunocompromised patients. Biofilm plays a significant role in the resistance of this bacterium and complicates the treatment of its infections. In this study, the effect of lyticase and β-glucosidase enzymes on the degradation of biofilms of P. aeruginosa strains isolated from cystic fibrosis and burn wound infections were assessed. Moreover, the decrease of ceftazidime minimum biofilm eliminating concentrations (MBEC) after enzymatic treatment was evaluated.<br><br>RESULTS: This study demonstrated the effectiveness of both enzymes in degrading the biofilms of P. aeruginosa. In contrast to the lyticase enzyme, β-glucosidase reduced the ceftazidime MBECs significantly (P < 0.05). Both enzymes had no cytotoxic effect on the A-549 human lung carcinoma epithelial cell lines and A-431 human epidermoid carcinoma cell lines.<br><br>CONCLUSION: Considering the characteristics of the β-glucosidase enzyme, which includes the notable degradation of P. aeruginosa biofilms and a significant decrease in the ceftazidime MBECs and non-toxicity for eukaryotic cells, this enzyme can be a promising therapeutic candidate for degradation of biofilms in burn wound patients, but further studies are needed.},
}
@article {pmid31830536,
year = {2019},
author = {Cao, Y and Naseri, M and He, Y and Xu, C and Walsh, LJ and Ziora, ZM},
title = {Non-antibiotic Antimicrobial Agents to Combat Biofilm-forming Bacteria.},
journal = {Journal of global antimicrobial resistance},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jgar.2019.11.012},
pmid = {31830536},
issn = {2213-7173},
abstract = {Biofilms can be produced by multiple species or by a single strain of bacteria. The biofilm state enhances the resistance of the resident microorganisms to antimicrobial agents by producing extracellular polymeric substances. Typically, antibiotics are used to stop the growth of bacteria, but emerging resistance has limited their effectiveness. Bacteria in biofilms are less susceptible to antibiotics compared with their free-floating state, as biofilms impair antibiotic penetration. To obviate this challenge, non-antibiotic antimicrobial agents are needed. This review describes two classes of these agents, namely antimicrobial nanoparticles and antimicrobial peptides. Applications of these antimicrobials in the food industry and medical applications are discussed, and the directions for future research are highlighted.},
}
@article {pmid31828607,
year = {2019},
author = {Berkes, E and Liao, YH and Neef, D and Grandalski, M and Monsul, N},
title = {Potentiated In Vitro Probiotic Activities of Lactobacillus fermentum LfQi6 Biofilm Biomass Versus Planktonic Culture.},
journal = {Probiotics and antimicrobial proteins},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12602-019-09624-8},
pmid = {31828607},
issn = {1867-1314},
support = {QI2019//Quorum Innovations LLC/ ; },
abstract = {In this study, we describe enhanced in vitro probiotic activities of preformed biofilms versus planktonic cultures of Lactobacillus fermentum LfQi6 (LfQi6), a lactic acid bacterium (LAB) isolated from the human microbiome. These evaluations are used to help predict host in vivo probiotic benefits and therefore indicate that LfQi6 may provide significant probiotic benefits in the human host when administered as preformed biofilms rather than as planktonic cultures. Specifically, LfQi6 biofilms demonstrated improved in vitro performance versus LfQi6 planktonic cultures for host gastrointestinal survival and engraftment, strain-specific antimicrobial and anti-biofilm activity against clinically significant pathogens, concurrent promotion of beneficial gastrointestinal commensal biofilms, beneficial commensal enzyme activities, and host cellular-protective glutathione antioxidant activity. Evaluation of LfQi6 according to the European Food Safety Authority (EFSA 2007, 2012, 2015) Guidelines and Joint FAO/WHO Expert Consultation on Evaluation of Health and Nutritional Properties of Probiotics in Food Evaluation of Probiotics in Food (FAO/WHO, 2002) demonstrates strain safety. In summary, in vitro evaluation of Lact. fermentum LfQi6 demonstrates significant evidence for strain-specific probiotic characteristics and safety. Moreover, strain-specific as well as biofilm-phenotype-specific benefits demonstrated in vitro furthermore suggest that in vivo use of LfQi6 biofilm biomass may be of greater benefit to the human host than the use of standard planktonic cultures. This concept - potentiating probiotic benefits through the use of preformed commensal biofilms - is novel and may serve to further broaden the application of microbial biofilms to human health.},
}
@article {pmid31827464,
year = {2019},
author = {Bansal, M and Nannapaneni, R and Kode, D and Chang, S and Sharma, CS and McDaniel, C and Kiess, A},
title = {Rugose Morphotype in Salmonella Typhimurium and Salmonella Heidelberg Induced by Sequential Exposure to Subinhibitory Sodium Hypochlorite Aids in Biofilm Tolerance to Lethal Sodium Hypochlorite on Polystyrene and Stainless Steel Surfaces.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2704},
pmid = {31827464},
issn = {1664-302X},
abstract = {Salmonella biofilms act as a continuous source for cross-contamination in the food processing environments. In this study, a stable rugose morphotype of Salmonella was first induced by sequential exposure to subinhibitory concentrations (SICs) of sodium hypochlorite (NaOCl) (ranging from 50 to 300 ppm over 18-day period) in tryptic soy broth. Then, rugose and smooth morphotypes of Salmonella Typhimurium ATCC 14028 and Salmonella Heidelberg ATCC 8326 were characterized for biofilm forming abilities on polystyrene and stainless steel surfaces. Rugose morphotype of both ATCC 14028 and ATCC 8326 exhibited higher Exopolysaccharide (EPS) formation than smooth morphotype (p ≤ 0.05). Also, the SICs of NaOCl (200 or 300 ppm in broth model) increased the biofilm formation ability of rugose morphotype of ATCC 8326 (p ≤ 0.05) but decreased that of ATCC 14028. The 2-day-old Salmonella biofilms were treated with biocidal concentrations of 50, 100, or 200 ppm NaOCl (pH 6.15) in water for 5, 10, or 20 min at room temperature. The biofilm reduction in CFU/cm2 for the rugose was lower than the smooth morphotype on both surfaces (p ≤ 0.05) by lethal NaOCl in water. Scanning electron micrographs on both polystyrene and stainless steel surfaces demonstrated that the rugose morphotype produced a denser biofilm than the smooth morphotype. Transmission electron micrographs revealed the cell wall roughness in rugose morphotype, which may help in tolerance to NaOCl. The gene expression data indicate that the expression of biofilm regulator (csgD), curli (csgA, csgB, and csgC), and cellulose (bcsE) was significantly increased in rugose morphotype when induced by sequential exposure of NaOCl SICs. These findings reveal that the rugose morphotype of S. Typhimurium and S. Heidelberg produced significantly denser biofilm on food contact surfaces, which also increased with sequential exposure to SICs of NaOCl in the case of S. Heidelberg, and these biofilms were more tolerant to biocidal NaOCl concentrations commonly used in the food processing plants.},
}
@article {pmid31827056,
year = {2019},
author = {Wu, S and Liu, Y and Zhang, H and Lei, L},
title = {Nano-graphene oxide with antisense vicR RNA reduced exopolysaccharide synthesis and biofilm aggregation for Streptococcus mutans.},
journal = {Dental materials journal},
volume = {},
number = {},
pages = {},
doi = {10.4012/dmj.2019-039},
pmid = {31827056},
issn = {1881-1361},
abstract = {Streptococcus mutans (S. mutans) has been proved to crucial cariogenic pathogens. Antisense vicR RNA reduced the transcription of virulence genes and lead to a reduction in biofilm formation. In the current study, a graphene-oxide plasmid transformation system was developed using interacted GO-polyethylenimine (PEI) complexes loaded with antisense vicR-expressing plasmid (GO-PEI-ASvicR). The particle size distribution and zeta potential of the GO-PEI-based ASvicR were evaluated. Quantitative real-time PCR assays were used to investigate the expression of S. mutans virulence genes. The exopolysaccharide (EPS) production in biofilm were evaluated by confocal laser scanning microscopy and anthrone method. We showed that GO-PEI could efficiently deliver the ASvicR-expressing plasmid into S. mutans cells and support excellent transcripts of ASvicR. Furthermore, GO-PEI-ASvicR significantly reduced virulent-associated gene expressions, suppressed biofilm aggregation and inhibited EPS accumulation. Our reports demonstrated that preserving nano-graphene oxide with antisense vicR RNA will be a more effective strategy for dental caries management.},
}
@article {pmid31825276,
year = {2019},
author = {Nguyen, TK and Argudín, MA and Deplano, A and Nhung, PH and Nguyen, HA and Tulkens, PM and Dodemont, M and Van Bambeke, F},
title = {Antibiotic Resistance, Biofilm Formation, and Intracellular Survival As Possible Determinants of Persistent or Recurrent Infections by Staphylococcus aureus in a Vietnamese Tertiary Hospital: Focus on Bacterial Response to Moxifloxacin.},
journal = {Microbial drug resistance (Larchmont, N.Y.)},
volume = {},
number = {},
pages = {},
doi = {10.1089/mdr.2019.0282},
pmid = {31825276},
issn = {1931-8448},
abstract = {Resistance is notoriously high in Asia but may not entirely explain therapeutic failures. Specific modes of bacterial life, such as biofilm or intracellular survival, may also contribute to the persistent and/or recurrent character of infections. Most Staphylococcus aureus isolates form biofilm and many survive and even thrive intracellularly. We collected 36 nonduplicate S. aureus isolates (including 18 methicillin-resistant S. aureus) from patients with clinical evidence of persistent or recurrent infections in a large tertiary Vietnamese hospital. We examined their antibiotic resistance profile (minimal inhibitory concentration determination) and clonal relatedness (spa and agr typing, pulsed field gel electrophoresis profiles). We then assessed the activity of moxifloxacin in both biofilms and infected phagocytes (moxifloxacin previously proved to be one of the most active antibiotics against reference strains in these models). spa-types t189 and t437 and agr group I were the most frequent. Among the 36 isolates, 30 were multidrug resistant but 30 were recovered from patients having received an active drug. All tested isolates produced biofilm and survived inside phagocytes. At its human Cmax, moxifloxacin was inactive on biofilms made by moxifloxacin-susceptible as well as moxifloxacin-resistant isolates. It caused only a modest intracellular colony-forming unit decrease against moxifloxacin-susceptible isolates and was inactive against those resistant to moxifloxacin. While our data confirm for this collection the high resistance levels and prevalence of endemic spa- or agr- types in Asia, they show that tolerance in both biofilm and phagocytes are correlated and markedly limit moxifloxacin activity, which goes in line with the suggested role of these modes of life in persistence or recurrence of infections.},
}
@article {pmid31825257,
year = {2019},
author = {Narendrakumar, L and Theresa, M and Krishnankutty Chandrika, S and Thomas, S},
title = {Tryptanthrin, a potential biofilm inhibitor against toxigenic Vibrio cholerae, modulating the global quorum sensing regulator, LuxO.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-11},
doi = {10.1080/08927014.2019.1696315},
pmid = {31825257},
issn = {1029-2454},
abstract = {Cholera caused by the Gram-negative bacterium Vibrio cholerae still remains a major health burden in developing countries due to its high transmissibility and multidrug resistance. Alternative strategies are in quest to curtail the disease focusing on antivirulent approaches, such as biofilm inhibition, which make bacteria more susceptible to antibiotic therapies. The biofilm state is important for V. cholerae pathogenesis and its persistence in the environment. In the present study, tryptanthrin, a phytochemical, has been identified as possessing strong anti-biofilm activity at sub MIC (2 µg ml-1) against V. cholerae. LuxO was identified as the putative target of tryptanthrin by molecular docking and real time analysis. The phytochemical was identified as safe and possessed synergistic action with ciprofloxacin, a commonly used quinolone antibiotic to treat cholera. Collectively, the study establishes the first report on the anti-biofilm property of tryptanthrin by targeting LuxO, which could serve as a potential antivirulent therapy to combat V. cholerae infections.},
}
@article {pmid31824466,
year = {2019},
author = {Lee, BH and Cole, S and Badel-Berchoux, S and Guillier, L and Felix, B and Krezdorn, N and Hébraud, M and Bernardi, T and Sultan, I and Piveteau, P},
title = {Biofilm Formation of Listeria monocytogenes Strains Under Food Processing Environments and Pan-Genome-Wide Association Study.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2698},
pmid = {31824466},
issn = {1664-302X},
abstract = {Concerns about food contamination by Listeria monocytogenes are on the rise with increasing consumption of ready-to-eat foods. Biofilm production of L. monocytogenes is presumed to be one of the ways that confer its increased resistance and persistence in the food chain. In this study, a collection of isolates from foods and food processing environments (FPEs) representing persistent, prevalent, and rarely detected genotypes was evaluated for biofilm forming capacities including adhesion and sessile biomass production under diverse environmental conditions. The quantity of sessile biomass varied according to growth conditions, lineage, serotype as well as genotype but association of clonal complex (CC) 26 genotype with biofilm production was evidenced under cold temperature. In general, relative biofilm productivity of each strain varied inconsistently across growth conditions. Under our experimental conditions, there were no clear associations between biofilm formation efficiency and persistent or prevalent genotypes. Distinct extrinsic factors affected specific steps of biofilm formation. Sudden nutrient deprivation enhanced cellular adhesion while a prolonged nutrient deficiency impeded biofilm maturation. Salt addition increased biofilm production, moreover, nutrient limitation supplemented by salt significantly stimulated biofilm formation. Pan-genome-wide association study (Pan-GWAS) assessed genetic composition with regard to biofilm phenotypes for the first time. The number of reported genes differed depending on the growth conditions and the number of common genes was low. However, a broad overview of the ontology contents revealed similar patterns regardless of the conditions. Functional analysis showed that functions related to transformation/competence and surface proteins including Internalins were highly enriched.},
}
@article {pmid31821931,
year = {2019},
author = {Sun, H and Mei, R and Zhang, XX and Ren, H and Liu, WT and Ye, L},
title = {Bacterial enrichment in highly-selective acetate-fed bioreactors and its application in rapid biofilm formation.},
journal = {Water research},
volume = {170},
number = {},
pages = {115359},
doi = {10.1016/j.watres.2019.115359},
pmid = {31821931},
issn = {1879-2448},
abstract = {In this study, we systematically investigated the bacterial community dynamics in highly-selective (strong hydraulic selection pressure and high organic loading rate) bioreactors with acetate as the sole carbon source. 16S rRNA gene high-throughput sequencing and metagenomic sequencing results showed that phenolics-degrading bacteria (PDB), which were mainly Acinetobacter species, in the newly-formed aerobic granules could account for >70% of the total bacteria. Near full-length 16S rRNA gene sequences obtained by cloning suggest that the PDB are potentially novel species because they are distantly related to known Acinetobacter species. However, these PDB only temporarily appeared in the early stage of the granule formation and their abundance quickly decreased along the reactor operation. To retain these PDB, we demonstrated that the newly-formed aerobic granules could accelerate biofilm formation in moving bed biofilm reactors (MBBRs), and the biofilm carriers showed gradually-increased phenol degradation performance in the MBBRs. While, the bacterial community in biofilm significantly changed during the operation process of the MBBRs and the community structure became more complicated than that in the aerobic granules. Collectively, this study provides new insights into the microbial ecology of sludge granulation and biofilm formation process in the wastewater treatment systems for remediating phenolic matters.},
}
@article {pmid31820066,
year = {2019},
author = {Khan, F and Lee, JW and Pham, DTN and Lee, JH and Kim, HW and Kim, YK and Kim, YM},
title = {Streptomycin mediated biofilm inhibition and suppression of virulence properties in Pseudomonas aeruginosa PAO1.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-019-10190-w},
pmid = {31820066},
issn = {1432-0614},
support = {20150220//Ministry of Oceans and Fisheries/ ; R2019053//National Institute of Fisheries Science, Republic of Korea/ ; },
abstract = {Pseudomonas aeruginosa is known as an opportunistic pathogen whose one of the antibiotic resistance mechanisms includes biofilm formation and virulence factor production. The present study showed that the sub-minimum inhibitory concentration (sub-MIC) of streptomycin inhibited the formation of biofilm and eradicated the established mature biofilm. Streptomycin at sub-MIC was also capable of inhibiting biofilm formation on the urinary catheters. In addition, the sub-MIC of streptomycin attenuated the bacterial virulence properties as confirmed by both phenotypic and gene expression studies. The optimal conditions for streptomycin to perform anti-biofilm and anti-virulence activities were proposed as alkaline TSB media (pH 7.9) at 35 °C. However, sub-MIC of streptomycin also exhibited a comparative anti-biofilm efficacy in LB media at similar pH level and temperature. Furthermore, this condition also improved the biofilm inhibition and eradication properties of streptomycin, tobramycin and tetracycline towards the biofilm formed by a clinical isolate of P. aeruginosa. Findings from the present study provide an important insight for further studies on the mechanisms of biofilm inhibition and dispersion of pre-existing biofilm by streptomycin as well as tobramycin and tetracycline under a specific culture environment.},
}
@article {pmid31819543,
year = {2019},
author = {De Souza, GM and Neto, ERDS and da Silva, AM and Iacia, MVMS and Rodrigues, MVP and Cataneli Pereira, V and Winkelstroter, LK},
title = {Comparative Study Of Genetic Diversity, Virulence Genotype, Biofilm Formation And Antimicrobial Resistance Of Uropathogenic Escherichia coli (UPEC) Isolated From Nosocomial And Community Acquired Urinary Tract Infections.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {3595-3606},
pmid = {31819543},
issn = {1178-6973},
abstract = {Introduction: Escherichia coli is a Gram-negative opportunistic human pathogen, which has aroused considerable medical interest for being involved in cases of urinary tract infection.<br><br>Aim: Characterize the E. coli isolated both in the hospital and in the community.<br><br>Methodology: A total of 200 E. coli isolated in urine samples from hospital and community were evaluated in biofilm formation assay and hydrophobicity MATS method. Antimicrobial susceptibility was performed through agar-diffusion technique. Virulence and ESBL production genes were observed through the polymerase chain reaction amplification of papC, fimH, fliC, kpsMTII, blaTEM, blaCTX-M, blaSHV , and blaOXA. The phylogenetic classification was based on the pattern chuA and yjaA and the region TspE4.C2 by PCR Multiplex.<br><br>Results: A higher frequency of non-adherent or poorly adherent isolates was observed in the community group. Approximately 85% of the community isolates were distributed in the highest hydrophilicity group (p<0.05). The level of resistant microorganisms was present at the same level in both source (p>0.05). About 14% of the hospital isolates were positive in the ESBL phenotypic detection test (p>0.05). Among the samples, 95% presented ESBL-encoding genes. The predominant phylogenetic group was B2 (78%). Community isolates showed a higher prevalence of virulence genes fimH, papC, and kpsMTII when compared to hospital samples.<br><br>Conclusion: These data confirm the worldwide trend that isolates in the community present sometimes higher levels of virulence and antimicrobial resistance.},
}
@article {pmid31817559,
year = {2019},
author = {Krummenauer, ME and Lopes, W and Garcia, AWA and Schrank, A and Gnoatto, SCB and Kawano, DF and Vainstein, MH},
title = {A Highly Active Triterpene Derivative Capable |of Biofilm Damage to Control Cryptococcus spp.},
journal = {Biomolecules},
volume = {9},
number = {12},
pages = {},
doi = {10.3390/biom9120831},
pmid = {31817559},
issn = {2218-273X},
support = {302637/2017-6//CNPq/ ; 420276/2016-5//CNPq/ ; 2018/08585-1//FAPESP/ ; 307191/2016-8//CNPq/ ; },
abstract = {Cryptococcus neoformans is an encapsulated yeast responsible for more than 180,000 deaths per year. The standard therapeutic approach against cryptococcosis is a combination of amphotericin B with flucytosine. In countries where cryptococcosis is most prevalent, 5-fluorocytosine is rarely available, and amphotericin B requires intravenous administration. C. neoformans biofilm formation is related to increased drug resistance, which is an important outcome for hospitalized patients. Here, we describe new molecules with anti-cryptococcal activity. A collection of 66 semisynthetic derivatives of ursolic acid and betulinic acid was tested against mature biofilms of C. neoformans at 25 µM. Out of these, eight derivatives including terpenes, benzazoles, flavonoids, and quinolines were able to cause damage and eradicate mature biofilms. Four terpene compounds demonstrated significative growth inhibition of C. neoformans. Our study identified a pentacyclic triterpenoid derived from betulinic acid (LAFIS13) as a potential drug for anti-cryptococcal treatment. This compound appears to be highly active with low toxicity at minimal inhibitory concentration and capable of biofilm eradication.},
}
@article {pmid31817522,
year = {2019},
author = {Rodríguez-López, P and Barrenengoa, AE and Pascual-Sáez, S and Cabo, ML},
title = {Efficacy of Synthetic Furanones on Listeria monocytogenes Biofilm Formation.},
journal = {Foods (Basel, Switzerland)},
volume = {8},
number = {12},
pages = {},
doi = {10.3390/foods8120647},
pmid = {31817522},
issn = {2304-8158},
support = {AGL2016-78549//Ministerio de Ciencia, Innovación y Universidades/ ; },
abstract = {Furanones are analogues of acylated homoserine lactones with proven antifouling activity in both Gram-positive and Gram-negative bacteria though the interference of various quorum sensing pathways. In an attempt to find new strategies to prevent and control Listeria monocytogenes biofilm formation on stainless steel (SS) surfaces, different concentrations of six synthetic furanones were applied on biofilms formed by strains isolated from food, environmental, and clinical sources grown onto AISI 316 SS coupons. Among the furanones tested, (Z-)-4-Bromo-5-(bromomethylene)-2(5H)-furanone and 3,4-Dichloro-2(5H)-furanone significantly (p < 0.05) reduced the adhesion capacity (>1 log CFU cm-2) in 24 h treated biofilms. Moreover, individually conducted experiments demonstrated that (Z-)-4-Bromo-5-(bromomethylene)-2(5H)-furanone was able to not only significantly (p < 0.05) prevent L. monocytogenes adhesion but also to reduce the growth rate of planktonic cells up to 48 h in a dose-dependent manner. LIVE/DEAD staining followed by epifluorescence microscopy visualisation confirmed these results show an alteration of the structure of the biofilm in furanone-treated samples. Additionally, it was demonstrated that 20 µmol L-1 of 3,4-Dichloro-2(5H)-furanone dosed at 0, 24 and 96 h was able to maintain a lower level of adhered cells (>1 log CFU cm-2; p < 0.05). Since furanones do not pose a selective pressure on bacteria, these results represent an appealing novel strategy for the prevention of L. monocytogenes biofilm grown onto SS.},
}
@article {pmid31817370,
year = {2019},
author = {Cattò, C and De Vincenti, L and Cappitelli, F and D'Attoma, G and Saponari, M and Villa, F and Forlani, F},
title = {Non-Lethal Effects of N-Acetylcysteine on Xylella fastidiosa Strain De Donno Biofilm Formation and Detachment.},
journal = {Microorganisms},
volume = {7},
number = {12},
pages = {},
doi = {10.3390/microorganisms7120656},
pmid = {31817370},
issn = {2076-2607},
support = {2017-0977//Fondazione Cariplo/ ; DD n. 495 del 14/10/2015 and n. 279 del 9/8/2016, Progetto di ricerca Linea B - STIPXYT//Regione Puglia/ ; },
abstract = {This study investigated in-vitro the non-lethal effects of N-acetylcysteine (NAC) on Xylella fastidiosa subspecies pauca strain De Donno (Xf-DD) biofilm. This strain was isolated from the olive trees affected by the olive quick decline syndrome in southern Italy. Xf-DD was first exposed to non-lethal concentrations of NAC from 0.05 to 1000 µM. Cell surface adhesion was dramatically reduced at 500 µM NAC (-47%), hence, this concentration was selected for investigating the effects of pre-, post- and co-treatments on biofilm physiology and structural development, oxidative homeostasis, and biofilm detachment. Even though 500 µM NAC reduced bacterial attachment to surfaces, compared to the control samples, it promoted Xf-DD biofilm formation by increasing: (i) biofilm biomass by up to 78% in the co-treatment, (ii) matrix polysaccharides production by up to 72% in the pre-treatment, and (iii) reactive oxygen species levels by 3.5-fold in the co-treatment. Xf-DD biofilm detachment without and with NAC was also investigated. The NAC treatment did not increase biofilm detachment, compared to the control samples. All these findings suggested that, at 500 µM, NAC diversified the phenotypes in Xf-DD biofilm, promoting biofilm formation (hyper-biofilm-forming phenotype) and discouraging biofilm detachment (hyper-attachment phenotype), while increasing oxidative stress level in the biofilm.},
}
@article {pmid31817122,
year = {2019},
author = {Płaczkiewicz, J and Adamczyk-Popławska, M and Lasek, R and Bącal, P and Kwiatek, A},
title = {Inactivation of Genes Encoding MutL and MutS Proteins Influences Adhesion and Biofilm Formation by Neisseria gonorrhoeae.},
journal = {Microorganisms},
volume = {7},
number = {12},
pages = {},
doi = {10.3390/microorganisms7120647},
pmid = {31817122},
issn = {2076-2607},
support = {UMO-2014/15/B/NZ6/02514//Narodowe Centrum Nauki/ ; NN301 165135//Ministry of Science and Higher Education in Poland/ ; },
abstract = {Neisseria gonorrhoeae is an etiological agent of gonorrhea, which remains a global health problem. This bacterium possesses MutL and MutS DNA repair proteins encoded by mutL and mutS genes, whose inactivation causes a mutator phenotype. We have demonstrated the differential gene expression in N. gonorrhoeae mutL and mutS mutants using DNA microarrays. A subset of differentially expressed genes encodes proteins that can influence adhesion and biofilm formation. Compared to the wild-type strain, N. gonorrhoeae mutL and mutS mutants formed denser biofilms with increased biofilm-associated biomass on the abiotic surface. The N. gonorrhoeae mutS::km, but not the mutL mutant, was also more adherent and invasive to human epithelial cells. Further, during infection of epithelial cells with N. gonorrhoeae mutS::km, the expression of some bacterial genes encoding proteins that can influence gonococcal adhesion was changed compared with their expression in cells infected with the wild-type gonococcus, as well as of human genes' encoding receptors utilized by N. gonorrhoeae (CD46, CEACAM 1, HSPG 2). Thus, deficiency in the mutS gene resulting in increased mutation frequency in singular organisms can be beneficial in populations because these mutants can be a source of features linked to microbial fitness.},
}
@article {pmid31817114,
year = {2019},
author = {Rampacci, E and Marenzoni, ML and Giovagnoli, S and Passamonti, F and Coletti, M and Pietrella, D},
title = {Phenotypic Characterization of Rhodococcus equi Biofilm Grown In Vitro and Inhibiting and Dissolving Activity of Azithromycin/Rifampicin Treatment.},
journal = {Pathogens (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/pathogens8040284},
pmid = {31817114},
issn = {2076-0817},
abstract = {Microbial biofilm has been implicated in a wide range of chronic infections. In spite of the fact that Rhodococcus equi is a recognized cause of chronic disease in animals and humans, few studies have focused on the sessile phenotype of R.equi. The aim of this research was to phenotypically characterize the biofilm development of R. equi and its answerability for hypo-responsiveness to macrolides and rifampicin. Biofilm formation is initiated by bacterial adhesion to the surface. In this work, the ability of R. equi to adhere to the surface of human lung epithelial cells was detected by a fluorometric adhesion test performed on 40 clinical isolates. Subsequently, the capability of R. equi to produce biofilm was investigated by colorimetric, fluorescence and scanning electron microscopy analysis, revealing a general slow growth of rhodococcal biofilm and different sessile phenotypes among field isolates, some also including filamented bacteria. Azithromycin treatment produced a higher long-term inhibition and dissolution of R. equi biofilms than rifampicin, while the two antibiotics combined boosted the anti-biofilm effect in a statistically significant manner, although this was not equally effective for all R. equi isolates. Increasing the MIC concentrations of drugs tenfold alone and in combination did not completely eradicate pre-formed R. equi biofilms, while a rifampicin-resistant isolate produced an exceptionally abundant extracellular matrix. These results have strengthened the hypothesis that biofilm production may occur as an antibiotic tolerance system in R. equi, potentially determining persistence and, eventually, chronic infection.},
}
@article {pmid31816593,
year = {2019},
author = {Chatterjee, S and Ghosh, R and Mandal, NC},
title = {Inhibition of biofilm- and hyphal- development, two virulent features of Candida albicans by secondary metabolites of an endophytic fungus Alternaria tenuissima having broad spectrum antifungal potential.},
journal = {Microbiological research},
volume = {232},
number = {},
pages = {126386},
doi = {10.1016/j.micres.2019.126386},
pmid = {31816593},
issn = {1618-0623},
abstract = {Fungal resistance against frequently used antifungal medicines used for invasive candidiasis and other fungal infections is directing scientist for searching and developing novel antifungal drugs. An endophytic fungal strain Alternaria tenuissima OE7 has been isolated from leaves of Ocimum tenuiflorum L. which showed antifungal activity against numbers of human pathogenic fungi including Trichophyton rubrum, Microsporum gypseum, Aspergillus parasiticus, A. flavus, A. fumigates, Candida albicans and C. tropicalis. Thermostable, non-proteinacious antifungal metabolites produced zones of inhibition against all pathogenic fungi tested. The ethyl acetate extract of the cell free supernatant was found inhibitory to the radial growth and conidial germination of T. rubrum and M. gypseum. It also showed cidal mode of action against C. albicans at a concentration of 1.0 mg/ml. Most interestingly, inhibition of biofilm formation and hyphal development of C. albicans were observed upon treatment with EA fraction at comparatively lower concentrations (100-500 μg/ml). Release of intracellular contents from treated cells of Candida and scanning electron microscopic observation suggested cellular disruptions by antifungal metabolites. Checkerboard study revealed synergy between EA fraction of OE7 (150 μg/ml) and fluconazole (30 μg/ml) with ƩFIC of 0.45. Two active fractions viz. band 'C' and band 'G' derived after thin layer chromatographic analysis showed inhibitory activity against C. albicans with MIC values of 80 μg/ml and 130 μg/ml respectively. GCMS analysis suggested presence of numbers of compounds in each active fraction. Overall observations attest the prospective role of the isolate OE7 as a potent candidate for the production of antifungal metabolites against human pathogenic fungi.},
}
@article {pmid31816527,
year = {2019},
author = {Lebleux, M and Abdo, H and Coelho, C and Basmaciyan, L and Albertin, W and Maupeu, J and Laurent, J and Roullier-Gall, C and Alexandre, H and Guilloux-Benatier, M and Weidmann, S and Rousseaux, S},
title = {New advances on the Brettanomyces bruxellensis biofilm mode of life.},
journal = {International journal of food microbiology},
volume = {318},
number = {},
pages = {108464},
doi = {10.1016/j.ijfoodmicro.2019.108464},
pmid = {31816527},
issn = {1879-3460},
abstract = {The wine spoilage yeast Brettanomyces bruxellensis can be found at several steps in the winemaking process due to its resistance to multiple stress conditions. The ability to form biofilm is a potential resistance strategy, although it has been given little attention so far for this yeast. In this work, the capacity to form biofilm and its structure were explored in YPD medium and in wine. Using microsatellite analysis, 65 isolates were discriminated into 5 different genetic groups from which 12 strains were selected. All 12 strains were able to form biofilm in YPD medium on a polystyrene surface. The presence of microcolonies, filamentous cells and extracellular polymeric substances, constituting the structure of the biofilm despite a small thickness, were highlighted using confocal and electronic microscopy. Moreover, different cell morphologies according to genetic groups were highlighted. The capacity to form biofilm in wine was also revealed for two selected strains. The impact of wine on biofilms was demonstrated with firstly considerable biofilm cell release and secondly growth of these released biofilm cells, both in a strain dependent manner. Finally, B. bruxellensis has been newly described as a producer of chlamydospore-like structures in wine, for both planktonic and biofilm lifestyles.},
}
@article {pmid31815139,
year = {2019},
author = {Bao, L and Guo, J and Feng, L and Zhou, X and Lu, Q},
title = {Efficacy of Artesunate against Pseudomonas aeruginosa Biofilm Mediated by Iron.},
journal = {BioMed research international},
volume = {2019},
number = {},
pages = {4810217},
pmid = {31815139},
issn = {2314-6141},
abstract = {Pseudomonas aeruginosa is capable of causing a variety of chronic infections due to the formation of biofilms. Iron is essential for growth of Pseudomonas aeruginosa, and therapies that interfere with iron may help treat P. aeruginosa infections. Herein, we investigated whether artesunate, which is a type of iron-dependent drug, could influence Pseudomonas aeruginosa biofilm formation and structure, including the underlying mechanisms. Artesunate could enhance twitching motility significantly and decrease the proportion of surviving cells in Pseudomonas aeruginosa biofilms in a dose-dependent manner. Artesunate treatment also reduced biofilm thickness, diffusion in the biomass, and the content of Fe(II). However, changes in biofilm structure and ion concentration were very similar following treatment with 512 μg/ml and 1024 μg/ml artesunate. Interestingly, both biofilm structure and surviving cell fraction were recovered after iron supplementation. These results suggest that artesunate interferes with Pseudomonas aeruginosa biofilms by decreasing bacterial viability and enhancing twitching motility in an iron-independent manner.},
}
@article {pmid31814741,
year = {2019},
author = {Eze, EC and El Zowalaty, ME},
title = {Combined Effects Of Low Incubation Temperature, Minimal Growth Medium, And Low Hydrodynamics Optimize Acinetobacter baumannii Biofilm Formation.},
journal = {Infection and drug resistance},
volume = {12},
number = {},
pages = {3523-3536},
doi = {10.2147/IDR.S203919},
pmid = {31814741},
issn = {1178-6973},
abstract = {Background: Biofilm formation is an important virulence factor expressed by Acinetobacter baumannii. It shields and protects microbial cells from host immune responses, antibiotics, and other anti-infectives. Its effects on Acinetobacter baumannii infection treatments notwithstanding, important environmental factors that influence its formation have not been fully investigated.<br><br>Methods: Biofilm formation was assessed using the qualitative modified Congo red assay and quantitative microtiter plate methods. The combined effect of temperature, medium and shear force was determined by measuring adherence (OD570 nm) in microtiter plate after incubation at 26°C, 30°C, and 37°C when biofilm-grown cells were cultured in the presence of minimal nutrient medium (EAOB) and nutrient-rich medium (TSB) without or with agitation at 50 rpm. Antibiotics susceptibility of meropenem, imipenem, and ciprofloxacin were tested with Kirby-Bauer disc method. P<0.05 was considered statistically significant in all the tests.<br><br>Results: A noticeable variation in adherence was observed among the isolates cultured with both media. Biofilm forming capacity of the isolates range from 0.09-0.33. The majority of the isolates had their relative biofilm-forming capacity significantly (p<0.05) higher than the positive control, Acinetobacter baumannii ATCC 19606. The biofilm biomass during growth in nutrient-rich medium (TSB) without shaking was significantly different (p<0.05; Tukey's test) among the three temperatures tested compared with when it was cultured in EAOB without shaking. A positive correlation was observed between biofilm formation and resistance to imipenem (r=0.2889; p=0.05). There was a statistically significant difference among the median of the three source groups (p<0.05) compared with the median between the source groups.<br><br>Conclusion: This observation extended further the view that A. baumannii biofilm formation is enhanced when nutrient-poor medium is used at room temperature (26°C) with or without agitation compared to growth at 37°C.},
}
@article {pmid31814249,
year = {2019},
author = {Fiallos, NM and Cecchin, D and de Lima, CO and Hirata, R and Silva, EJNL and Sassone, LM},
title = {Antimicrobial effectiveness of grape seed extract against Enterococcus faecalis biofilm: A Confocal Laser Scanning Microscopy analysis.},
journal = {Australian endodontic journal : the journal of the Australian Society of Endodontology Inc},
volume = {},
number = {},
pages = {},
doi = {10.1111/aej.12390},
pmid = {31814249},
issn = {1747-4477},
support = {001//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; E-26/202.839/2015//Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro/ ; //Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; },
abstract = {This study evaluated the antimicrobial effectiveness of 6.5% Vitis vinifera grape seed extract (GSE) against Enterococcus faecalis biofilm using confocal laser scanning microscopy (CLSM). Saline solution (SS), 5.25% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX) were used for comparison. Dentin discs were inoculated with E. faecalis strain establishing a 3-week-old biofilm. Discs (n = 10) were exposed to 5.25% NaOCl, 2% CHX, 6.5% GSE and SS (negative control) for 10 min. Discs were stained with the fluorescent LIVE/DEAD-BacLight™ dye and analysed using CLSM. The proportion of dead cells in biofilm was analysed using one-way anova and Tukey tests (P < 0.05). A higher proportion of dead cells was found in GSE group compared with CHX and SS (P < 0.05). NaOCl group was associated with the highest proportion of dead cells (P < 0.05). GSE presented antimicrobial activity against E. faecalis; however, NaOCl was the most effective irrigant solution. GSE was more effective than CHX and SS.},
}
@article {pmid31813834,
year = {2019},
author = {Su, S and Yin, P and Li, J and Chen, G and Wang, Y and Qu, D and Li, Z and Xue, X and Luo, X and Li, M},
title = {In vitro and in vivo anti-biofilm activity of pyran derivative against Staphylococcus aureus and Pseudomonas aeruginosa.},
journal = {Journal of infection and public health},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jiph.2019.10.010},
pmid = {31813834},
issn = {1876-035X},
abstract = {BACKGROUND: The development of bacterial biofilm can cause severe chronic infections and antibiotic resistance. Therefore, it poses a significant threat to public health. Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) are two major pathogens that can cause biofilm-associated infections, which leads to the urgent necessity of developing new agents with biofilm-forming inhibitory ability.<br><br>METHODS: A series of pyran derivatives were synthesized and characterized, and their in vitro anti-biofilm activity against S. aureus and P. aeruginosa were measured by minimal biofilm inhibitory concentration assay and FITC dye staining. The in vivo antibiofilm therapeutical effects were evaluated in S. aureus induced tissue cage infection mice model and P. aeruginosa induced urinary tract catheter infection rat model.<br><br>RESULTS: Several pyran derivatives showed the in vitro anti-biofilm activity against S. aureus and P. aeruginosa, and the activity of these compounds was not mediated through the accessory gene regulator (agr) quorum sensing system of S. aureus. One of these pyran derivatives, namely 2-amino-4-(2,6-dichlorophenyl)-3-cyano-5-oxo-4H,5H-pyrano[3,2c]chromene, exhibited significant inhibitory biofilm-formation activity in S. aureus tissue cage infection mice model and in the P. aeruginosa-infected urinary tract catheters of experimental rats.<br><br>CONCLUSIONS: The data indicated that this pyran derivative is a possible lead compound that can be used for the development of novel anti-biofilm agents against S. aureus and P. aeruginosa infection.},
}
@article {pmid31813049,
year = {2019},
author = {Liu, Y and Feng, H and Fu, R and Zhang, N and Du, W and Shen, Q and Zhang, R},
title = {Induced root-secreted D-galactose functions as a chemoattractant and enhances the biofilm formation of Bacillus velezensis SQR9 in an McpA-dependent manner.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-019-10265-8},
pmid = {31813049},
issn = {1432-0614},
support = {31672232//National Natural Science Foundation of China/ ; 31600088//National Natural Science Foundation of China/ ; 31572214//National Natural Science Foundation of China/ ; 2018YFD0500201//the National Key R &amp; D Program of China/ ; },
abstract = {Chemotaxis towards root exudates and subsequent biofilm formation are very important for root colonization and for providing the beneficial functions of plant growth-promoting rhizobacteria (PGPRs). In this study, in comparison with other root-secreted compounds, D-galactose in the root exudates of cucumber was found to be a strong chemoattractant at the concentration of 1 μM for Bacillus velezensis SQR9. Chemotaxis assays with methyl-accepting chemotaxis proteins (MCPs) deletion strains demonstrated that McpA was solely responsible for chemotaxis towards D-galactose. Interestingly, D-galactose significantly enhanced the biofilm formation of SQR9 in an McpA-dependent manner. Further experiment showed that D-galactose also enhanced root colonization by SQR9. In addition, the secretion of D-galactose by cucumber roots could be induced by inoculation with SQR9, indicating that D-galactose may be an important signal in the interaction between plant and SQR9. These findings suggested that the root-secreted D-galactose was a signal, the secretion of which was induced by the beneficial bacteria, and which in turn induced colonization of the bacteria.},
}
@article {pmid31812976,
year = {2019},
author = {Płusa, T},
title = {[The importance of biofilm in the context of increasing bacterial resistance to antibiotics].},
journal = {Polski merkuriusz lekarski : organ Polskiego Towarzystwa Lekarskiego},
volume = {47},
number = {281},
pages = {197-202},
pmid = {31812976},
issn = {1426-9686},
abstract = {Biofilm is a form of bacterial life in extreme environmental conditions. The known structure and functions of biofilm indicate that it is one of the most widespread and most successful life forms on earth. The quorum sensing (QS) system plays a key role in biofilm because it is a mechanism by which bacteria regulate the gene expression profile according to the size of the microbial population, causing the formation of different forms of biofilm. The QS includes the auto-inducer-1 (AI- 1) system, which uses N-acyl-homoserine lactones as a signaling factor in the formation of biofilm by Acinetobacter baumannii and Pseudomonas aeruginosa, and the auto-inducer-2 (AI-2) system identified as furanosyl borate diester present in Gram-positive and Gram-negative bacteria. Antimicrobial proteins (AMPs) have a natural antibacterial effect, which are produced by eukaryocytes and prokaryocytes, and have the ability to form pores in the bacterial cell membrane or interfere with its function. On the other hand, biofilm degrading enzymes - DNase I, alpha-amylase and dispersin B - reduce the weight of exopolysaccharides (EPS) and the number of cells in the biofilm. Natural compounds that inhibit the formation of bacterial biofilm have been distinguished, so-called QS inhibitors (QSI) and which &quot;quench&quot; active process (QSQ). In turn, genetic diversification of microorganisms in biofilm is largely responsible for shaping antibiotic resistance. The combined use of antibiotics with nanoparticles seems to be the most promising therapeutic option for bacterial biofilm. Silver nanoparticles with citrate in combination with aztreonam have been shown to have significant biofilm-destroying efficacy for Pseudomonas aeruginosa, and selenium nanoparticles used together with ampicillin, oxacillin and penicillin in 94% inhibited and interrupted the MRSA (methicillin-resistent) biofilm. Research on biofilm control is very advanced and will soon be subject to clinical evaluation.},
}
@article {pmid31812797,
year = {2019},
author = {Borowski, RGV and Barros, MP and da Silva, DB and Lopes, NP and Zimmer, KR and Staats, CC and de Oliveira, CB and Giudice, E and Gillet, R and Macedo, AJ and Gnoatto, SCB and Zimmer, AR},
title = {Red pepper peptide coatings control Staphylococcus epidermidis adhesion and biofilm formation.},
journal = {International journal of pharmaceutics},
volume = {574},
number = {},
pages = {118872},
doi = {10.1016/j.ijpharm.2019.118872},
pmid = {31812797},
issn = {1873-3476},
abstract = {Medical devices (indwelling) have greatly improved healthcare. Nevertheless, infections related to the use of these apparatuses continue to be a major clinical concern. Biofilms form on surfaces after bacterial adhesion, and they function as bacterial reservoirs and as resistance and tolerance factors against antibiotics and the host immune response. Technological strategies to control biofilms and bacterial adhesion, such as the use of surface coatings, are being explored more frequently, and natural peptides may promote their development. In this study, we purified and identified antibiofilm peptides from Capsicum baccatum (red pepper) using chromatography-tandem mass spectrometry, MALDI-MS, MS/MS and bioinformatics. These peptides strongly controlled biofilm formation by Staphylococcus epidermidis, the most prevalent pathogen in device-related infections, without any antibiotic activity. Furthermore, natural peptide-coated surfaces dislayed effective antiadhesive proprieties and showed no cytotoxic effects against different representative human cell lines. Finally, we determined the lead peptide predicted by Mascot and identified CSP37, which may be useful as a prime structure for the design of new antibiofilm agents. Together, these results shed light on natural Capsicum peptides as a possible antiadhesive coat to prevent medical device colonization.},
}
@article {pmid31812752,
year = {2019},
author = {Garcia, LGS and de Melo Guedes, GM and Fonseca, XMQC and Pereira-Neto, WA and Castelo-Branco, DSCM and Sidrim, JJC and de Aguiar Cordeiro, R and Rocha, MFG and Vieira, RS and Brilhante, RSN},
title = {Antifungal activity of different molecular weight chitosans against planktonic cells and biofilm of Sporothrix brasiliensis.},
journal = {International journal of biological macromolecules},
volume = {143},
number = {},
pages = {341-348},
doi = {10.1016/j.ijbiomac.2019.12.031},
pmid = {31812752},
issn = {1879-0003},
abstract = {Sporotrichosis, caused by Sporothrix schenckii complex species, is the most prevalent subcutaneous mycosis in many areas of Latin America. Chitosan has been used as an antifungal agent; however the effects of the molecular weight (MW) of chitosan (i.e. high (HMW), medium (MMW) and low (LMW) molecular weight chitosan) on S. brasiliensis has not been well described, particularly on biofilms. Effects on the planktonic form activity of S. brasiliensis were quantified by broth microdilution, while anti-biofilm activity was quantified by measuring metabolic activity via XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide and biomass formation (crystal violet). The molecular weight of chitosan modulated its effect on the planktonic form of S. brasiliensis, presenting lower MIC values for LMW chitosan. With regards both the adhesive and mature phases of biofilm, the LMW chitosan reduced biomass and metabolic activity most effectively. This study confirms the effects of the molecular weight and deacetylation degree of chitosan on its antifungal properties for potentially pathogenic fungi.},
}
@article {pmid31812393,
year = {2019},
author = {Wang, J and Liu, Q and Wu, B and Hu, H and Dong, D and Yin, J and Ren, H},
title = {Effect of salinity on mature wastewater treatment biofilm microbial community assembly and metabolite characteristics.},
journal = {The Science of the total environment},
volume = {},
number = {},
pages = {134437},
doi = {10.1016/j.scitotenv.2019.134437},
pmid = {31812393},
issn = {1879-1026},
abstract = {The response mechanism of wastewater treatment biofilms to salt stress has not yet been fully established. The aim of this study was to reveal the comprehensive biological effects of salinity on biofilm microbial community and metabonomic characteristics. The study assessed performance at a range of sodium chloride (NaCl) concentrations of 0.6, 14 and 20 g/L. Biofilm coverage rate decreased significantly with increasing NaCl concentrations. High NaCl concentrations resulted in more compact and smoother biofilm morphologies. NaCl concentrations affected bacterial community variation at the class and genus level, with Gammaproteobacteria being the most dominant Proteobacteria, exhibiting NaCl tolerance at concentrations ranging from 0 to 20 g/L. Also, NaCl sensitive or tolerant species were identified, such as Pseudomonas and Planococcus, respectively. Dominant metabolites in wastewater treatment biofilms belonging to nucleotide, lipid, vitamin, amino acid and carbohydrate metabolism pathways decreased with increasing NaCl concentrations. High concentrations of NaCl regulated cell motility, transcription and membrane transport functions. In particular, the activity of ABC transporters were up-regulated at NaCl concentrations of 0.6 g/L and down-regulated at higher salinity concentrations. In addition, transcription machinery were inhibited under the stress of 14 g/L NaCl. These findings further our understanding of the short-term adaption mechanisms of wastewater treatment biofilms to high NaCl concentration environments.},
}
@article {pmid31812076,
year = {2019},
author = {Rahim, MI and Szafrański, SP and Ingendoh-Tsakmakidis, A and Stiesch, M and Mueller, PP},
title = {Evidence for inoculum size and gas interfaces as critical factors in bacterial biofilm formation on magnesium implants in an animal model.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {186},
number = {},
pages = {110684},
doi = {10.1016/j.colsurfb.2019.110684},
pmid = {31812076},
issn = {1873-4367},
abstract = {Infections of medical implants caused by bacterial biofilms are a major clinical problem. Bacterial colonization is predicted to be prevented by alkaline magnesium surfaces. However, in experimental animal studies, magnesium implants prolonged infections. The reason for this peculiarity likely lies within the ‒still largely hypothetical‒ mechanism by which infection arises. Investigating subcutaneous magnesium implants infected with bioluminescent Pseudomonas aeruginosa via in vivo imaging, we found that the rate of implant infections was critically dependent on a surprisingly high quantity of injected bacteria. At high inocula, bacteria were antibiotic-refractory immediately after infection. High cell densities are known to limit nutrient availability, restricting proliferation and trigger quorum sensing which could both contribute to the rapid initial resistance. We propose that gas bubbles such as those formed during magnesium corrosion, can then act as interfaces that support biofilm formation and permit long-term survival. This model could provide an explanation for the apparent ineffectiveness of innovative contact-dependent bactericidal implant surfaces in patients. In addition, the model points toward air bubbles in tissue, either by inclusion during surgery or by spontaneous gas bubble formation later on, could constitute a key risk factor for clinical implant infections.},
}
@article {pmid31812042,
year = {2019},
author = {Suárez, JI and Aybar, M and Nancucheo, I and Poch, B and Martínez, P and Rittmann, BE and Schwarz, A},
title = {Influence of operating conditions on sulfate reduction from real mining process water by membrane biofilm reactors.},
journal = {Chemosphere},
volume = {244},
number = {},
pages = {125508},
doi = {10.1016/j.chemosphere.2019.125508},
pmid = {31812042},
issn = {1879-1298},
abstract = {Two H2-based membrane biofilm reactor (H2-MBfR) systems, differing in membrane type, were tested for sulfate reduction from a real mining-process water having low alkalinity and high concentrations of dissolved sulfate and calcium. Maximum sulfate reductions were 99%, with an optimum pH range between 8 and 8.5, which minimized any toxic effect of unionized hydrogen sulfide (H2S) on sulfate-reducing bacteria (SRB) and calcite scaling on the fibers and in the biofilm. Although several strategies for control of pH and gas back-diffusion were applied, it was not possible to sustain a high degree of sulfate reduction over the long-term. The most likely cause was precipitation of calcite inside the biofilm and on the surface of fibers, which was shown by scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) analysis. Another possible cause was a decline in pH, leading to inhibition by H2S. A H2/CO2 mixture in the gas supply was able to temporarily recover the effectiveness of the reactors and stabilize the pH. Biomolecular analysis showed that the biofilm was comprised of 15-20% SRB, but a great variety of autotrophic and heterotrophic genera, including sulfur-oxidizing bacteria, were present. Results also suggest that the MBfR system can be optimized by improving H2 mass transfer using fibers of higher gas permeability and by feeding a H2/CO2 mixture that is automatically adjusted for pH control.},
}
@article {pmid31811888,
year = {2019},
author = {Narenji, H and Teymournejad, O and Rezaee, MA and Taghizadeh, S and Mehramuz, B and Aghazadeh, M and Asgharzadeh, M and Madhi, M and Gholizadeh, P and Ganbarov, K and Yousefi, M and Pakravan, A and Dal, T and Ahmadi, R and Samadi Kafil, H},
title = {Antisense peptide nucleic acids againstftsZ andefaA genes inhibit growth and biofilm formation of Enterococcusfaecalis.},
journal = {Microbial pathogenesis},
volume = {139},
number = {},
pages = {103907},
doi = {10.1016/j.micpath.2019.103907},
pmid = {31811888},
issn = {1096-1208},
abstract = {Enterococcus faecalis is one of the important causes of nosocomial infections. Nowadays, increasing prevalence of antibiotic-resistant bacteria and slow progress in recognizing new antimicrobial agents has limited the efficiency of conventional antibiotics, which cause to find novel strategies to overcome bacteria. Therefore, in this study, we aimed to assess the role of efaA gene in the biofilm formation and the role of ftsZ gene in the controlling of bacterial growth by the anti-sense PNAs(Peptide Nucleic Acid).E. faecalis ATCC® 29212™was used for the study of PNAs designed to targeting the start codon section of the ftsZ andefaA genes. PNA attachment to RNA was confirmed by blotting. Electroporation technique was used for the intracellular transfer of anti-ftsZ PNAs. The spot-plating method was used to the assessment of alteration in bacterial growth. Biofilm formation assay and real-time PCR were used for detection of biofilm inhibitory effect of cell penetrating peptide (CPP) conjugated to anti-efaA PNAs.ByftsZ PNAs treatment, no growth was seen from the strain in agar by a spot plating method and the inhibition zone of anti-ftsZ PNAs was not seen. PNAs against the efaA gene decreased by 95% the expression of the efaA gene and biofilm formation. In addition, the(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) MTT assay showed no toxicity on MCF7 cells for both of anti-ftsZand anti-efaA PNAs.This study used new genetic and molecular tools to inhibit pathogenicity and infection by E. faecalis. In this study, we suggested that efaA gene plays a critical role in the biofilm formation and anti-efaA PNAs could decrease the formation of biofilm, as well as, anti-ftsZ PNAs could eliminate bacterial growth.},
}
@article {pmid31811560,
year = {2019},
author = {Çam, S and Brinkmeyer, R},
title = {The effects of temperature, pH, and iron on biofilm formation by clinical versus environmental strains of Vibrio vulnificus.},
journal = {Folia microbiologica},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12223-019-00761-9},
pmid = {31811560},
issn = {1874-9356},
abstract = {Due to the nature of Vibrio vulnificus infections (i.e., gastroenteritis and septicemia), only very few studies of a biofilm-associated form in this pathogen's life cycle have been conducted. We proposed that biofilm production by clinical strains of V. vulnificus would be higher than by environmental strains. Biofilm formation by clinical and environmental reference strains was tested under different temperatures (24, 30, and 37 °C), pH (5.5, 7.5, and 8.5) and iron concentrations (18, 30, 50, 100, and 200 μM). Biofilm production by clinical strains was consistently higher (p < 0.001) at 24 °C than by environmental strains. Higher biofilm production was observed at pH 5.5 by all strains. Growth rates were lowest at pH 5.5 for environmental strains but for clinical strains there were no differences at pH 5.5, 7.5, and 8.5, demonstrating a tolerance to acidic and alkaline conditions. There was a strong, direct correlation between iron concentration in the growth medium and biofilm production by all strains tested. The current study indicates that biofilm formation might be important for the survival of V. vulnificus in vivo as well as in the marine environment. With regard to temperature and pH, higher biofilm production appears to be a trait of clinical strains and could be considered a virulence determinant in V. vulnificus.},
}
@article {pmid31811221,
year = {2019},
author = {Husain, FM and Ansari, AA and Khan, A and Ahmad, N and Albadri, A and Albalawi, TH},
title = {Mitigation of acyl-homoserine lactone (AHL) based bacterial quorum sensing, virulence functions, and biofilm formation by yttrium oxide core/shell nanospheres: Novel approach to combat drug resistance.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {18476},
pmid = {31811221},
issn = {2045-2322},
support = {RG -1439-089//KSU | Deanship of Scientific Research, King Saud University (Deanship of Scientific Research)/ ; RG -1439-089//KSU | Deanship of Scientific Research, King Saud University (Deanship of Scientific Research)/ ; RG -1439-089//KSU | Deanship of Scientific Research, King Saud University (Deanship of Scientific Research)/ ; RG -1439-089//KSU | Deanship of Scientific Research, King Saud University (Deanship of Scientific Research)/ ; RG -1439-089//KSU | Deanship of Scientific Research, King Saud University (Deanship of Scientific Research)/ ; },
abstract = {The present study evaluated the efficacy of Y2O3:Tb (core) and Y2O3:Tb@SiO2 nanospheres (core/shell NSs) against virulence functions regulated by quorum sensing (QS) and biofilm formation in pathogenic bacteria. Scanning electron microscope (SEM) images were used to study the size, shape, and morphology. The images clearly displayed spherical shaped, mono-dispersed particles with narrow size distribution and an average grain size of 110-130 nm. The chemical composition of the samples was determined by using energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS). We determined the impact of core and core/shell NSs on QS using sensor strains of Chromobacterium violaceum CVO26 and Pseudomonas aeruginosa PAO1 in a comparative study. Sub-MICs of core and core/shell NSs substantially suppressed QS-controlled violacein production in C. violaceum. Similar concentration-dependent effect of sub-MICs of synthesized core and core/shell NSs was observed in the QS-regulated virulence functions (elastase, total protease, pyocyanin production, swarming motility, and exopolysaccharide production) in PAO1. A concentration-dependent decrease (14-60%) was recorded in the biofilm forming capability of PAO1, upon treatment with core and core/shell NSs. Moreover, core/shell NSs were more effective in inhibiting biofilm at higher tested concentrations as compared to core-NSs. The synthesized NSs demonstrated significantly impaired attachment of cells to the microtiter plate indicating that NSs target biofilm inhibition at the attachment stage. Based on these results, we predict that core and core/shell NSs may be an alternative to combat the threat of drug-resistant pathogenic bacteria.},
}
@article {pmid31809574,
year = {2019},
author = {Li, Q and Yin, L and Xue, M and Wang, Z and Song, X and Shao, Y and Liu, H and Tu, J and Qi, K},
title = {The transcriptional regulator PhoP mediates the tolC molecular mechanism on APEC biofilm formation and pathogenicity.},
journal = {Avian pathology : journal of the W.V.P.A},
volume = {},
number = {},
pages = {1-29},
doi = {10.1080/03079457.2019.1701182},
pmid = {31809574},
issn = {1465-3338},
abstract = {As a transcriptional regulator of the classical binary regulatory system, PhoP plays an important role in the life activities of avian pathogenic Escherichia coli (APEC). In previous experiments, we found that the absence of phoP affects APEC biofilm formation and pathogenicity. To further explore the molecular mechanism of phoP regulation of these phenomena, the differentially expressed gene tolC was screened based on phoP-derived transcriptional data, and the specific sequence identity of the PhoP binding sequence was predicted by bioinformatics and verified by electrophoretic mobility shift assay (EMSA). The results showed that PhoP can directly bind to the tolC promoter. On this basis, tolC deletion and complementary strains were constructed. Biofilm formation was quantified by crystal violet staining and rdar morphology change was observed in these strains. Loss of tolC reduced biofilm formation. We also examined pathological changes in organ paraffin sections by challenging chicks with the strains. After loss of tolC, the chick symptoms of pericarditis and liver and spleen enlargement were alleviated, and pathogenicity to the host cells was decreased. Additionally, quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that tolC deletion downregulated secA/secB/secE/secY transcript levels, which are part of the T2SS secreting virulence effector element. These results indicate that tolC contributes to the phoP-mediated effect on APEC biofilm formation and pathogenicity.},
}
@article {pmid31809192,
year = {2019},
author = {Ma, Z and Stanford, K and Bie, XM and Niu, YD and McAllister, TA},
title = {Effects of Beef Juice on Biofilm Formation by Shiga Toxin-Producing Escherichia coli on Stainless Steel.},
journal = {Foodborne pathogens and disease},
volume = {},
number = {},
pages = {},
doi = {10.1089/fpd.2019.2716},
pmid = {31809192},
issn = {1556-7125},
abstract = {Shiga toxin-producing Escherichia coli (STEC) are a leading cause of foodborne illnesses worldwide, with beef and beef products as a common food reservoir. STEC strains may be present in beef-processing environments in the form of biofilms. The exudate of raw beef, also referred to as beef juice, has been identified as an important source of bacterial contamination on food-processing surfaces. This study applied beef juice as a food-based model to study its effects on biofilm formation of six STEC isolates on stainless steel. Crystal violet staining and cell enumeration demonstrated that beef juice inhibited the biofilm formation of strains O113, O145, and O91 up to 24 h at 22°C, but that biofilm increased (p < 0.05) thereafter over 72 h. Biofilms formed by O157, O111, and O45 were not affected by the addition of beef juice over the whole incubation period. Electron microscopy showed that the morphology of biofilm cells was altered and more extracellular matrix was produced with beef juice than with M9 medium. The present study demonstrated that beef juice residues on stainless steel can enhance biofilm formation of some STEC strains. Thorough and frequent cleaning of meat residues and exudate during meat production and handling is critical to reduce STEC biofilm formation even at 13°C.},
}
@article {pmid31808241,
year = {2019},
author = {Mu, YQ and Xie, TT and Zeng, H and Chen, W and Wan, CX and Zhang, LL},
title = {Streptomyces-derived actinomycin D inhibits biofilm formation via downregulating ica locus and decreasing production of PIA in Staphylococcus epidermidis.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14543},
pmid = {31808241},
issn = {1365-2672},
support = {2017DB002//Innovating Project for Developing to the South in Xinjiang Production＆Construction Corps/ ; U1703236//National Science Foundation of China-Xinjiang joint Grant/ ; NCET-11-1071//New Century Excellent Talents in University/ ; 2017CB014//Microbial Resources Utilization Innovation Team in Key Field of Xinjiang Production ＆Construction Crops/ ; 2009JC07//Ph. D in Xinjiang Production＆Construction Corps/ ; 31260026//National Natural Science Foundation of China/ ; },
abstract = {AIM: The objective of this study was to investigate the biofilm inhibitory activity of Streptomyces-derived actinomycin D against biofilm formation by Staphylococcus epidermidis.<br><br>METHODS AND RESULTS: The microtitre plate method and microscopy were used to detect the biofilm formation of S. epidermidis. And an attempt was made to detect the effect of actinomycin D on important biofilm components, exopolysaccharides (EPS) in S. epidermidis using precolumn derivation HPLC. Also cell surface hydrophobicities of S. epidermidis were assessed to explore action mechanisms. The qPCR was performed to demonstrate the genetic mechanisms of biofilm formation by S. epidermidis. Unlike other antibiotics, actinomycin D (1·5 μg ml-1) from Streptomyces luteus significantly inhibited biofilm formation by S. epidermidis. Additionally, it effectively inhibited S. epidermidis cells from adhering to glass slides. Actinomycin D downregulated ica locus and then the reduced polysaccharide intercellular adhesin production caused S. epidermidis cells to become less hydrophobic, thus supporting its anti-biofilm effect.<br><br>CONCLUSION: Streptomyces-derived actinomycin D is active in inhibiting the biofilm formation of S. epidermidis.<br><br>Actinomycin D can be used as a promising antibiofilm agent in inhibiting S. epidermidis biofilm formation. The study is also the first insight into how actinomycin D inhibited the biofilm formation of S. epidermidis. Actinomycin D could potentially be used to reduce the risk of biofilm-associated infections. Our study also suggests that the metabolites from Actinomycete strains keep further attention as potential antibiofilm agents against biofilm formation of S. epidermidis, even biofilm infections of the other bacteria.},
}
@article {pmid31807847,
year = {2019},
author = {Al-Mousawi, AH and Al-Kaabi, SJ and Albaghdadi, AJH and Almulla, AF and Raheem, A and Algon, AAA},
title = {Effect of Black Grape Seed Extract (Vitis vinifera) on Biofilm Formation of Methicillin-Resistant Staphylococcus aureus and Staphylococcus haemolyticus.},
journal = {Current microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00284-019-01827-0},
pmid = {31807847},
issn = {1432-0991},
abstract = {Grape seeds are considered one of the most important sources for phenolic and other compounds and is globally consumed for the biological value of its active ingredients. The increasing prevalence of Methicillin-resistant Staphylococcus aureus-related infections has become a very challenging health issue worldwide. This work aims at examining the antibacterial activity of alcoholic extract of black grape seeds (Vitis vinifera) against biofilm formation by Staphylococcus aureus and Staphylococcus haemolyticus. Staphylococcal bacterial isolates were first clinically confirmed using the VITEK-2compact system (ID and AST), and four isolates were selected depending on virulence and resistance to different types of antibiotics. The ability of S. aureus and S. haemolyticus isolates to form biofilm was examined using a standardized 96-well microtiter plate method. Furthermore, the effect of Moxifloxacin and Penicillin G with MIC, sub-MIC and sub-sub-MIC in preventing S. aureus and S. haemolyticus biofilm production, as well as that of the grape seed extract (180 mg/ml) were tested against biofilm formation. Our data indicate that all of the Staphylococcal bacterial isolates were able to produce biofilm which was prevented by the methanolic extracts of the crude seeds of Vitis vinifera rich in galloylated catechin esters of gallic acid. A significant (P < 0.001) synergistic effect between Penicillin G, Moxifloxacin with MIC, sub-MIC and sub-sub-MIC and that of the methanolic extract of Vitis vinifera (180 mg/ml) against bacterial biofilm formation was also detected. This report confirms the antibacterial activity of the methanolic extract of the black grape seeds.},
}
@article {pmid31807362,
year = {2019},
author = {Hu, WS and Nam, DM and Choi, JY and Kim, JS and Koo, OK},
title = {Anti-attachment, anti-biofilm, and antioxidant properties of Brassicaceae extracts on Escherichia coli O157:H7.},
journal = {Food science and biotechnology},
volume = {28},
number = {6},
pages = {1881-1890},
doi = {10.1007/s10068-019-00621-9},
pmid = {31807362},
issn = {2092-6456},
abstract = {Bacteria can survive and persist in food processing environments by attachment and biofilm formation and transfer to food products, causing serious foodborne illness. In this study, we investigated natural substances that belong to the family Brassicaceae to determine whether they have potential anti-attachment activities against Escherichia coli O157:H7. The inhibition of biofilm formation was evaluated by crystal violet and resazurin assays at different stages of biofilm formation (initial attachment, biofilm formation, and after biofilm development) of E. coli O157:H7. The sessile cells were reduced to a range of 13.8-31.3% by young radish, radish, radish sprout, red cabbage, and kale extracts, and the viability was reduced to between 5.83 and 51.5%. The radical scavenging activities and the presence of polyphenolic compounds were compared. The presence of phenolic compounds such as gallic acid, caffeic acid, and phenylethyl ITC in the Brassicaceae family verified the potential use as a natural anti-biofilm substituent against E. coli O157:H7.},
}
@article {pmid31807272,
year = {2019},
author = {Hurley, CM and Hechtl, D and Ng, KC and McHugh, J and Sehgal, R and Regan, MC},
title = {Biofilm-sealed perforation of the gastric body: a rare sequela of gastric band erosion.},
journal = {Journal of surgical case reports},
volume = {2019},
number = {9},
pages = {rjz263},
pmid = {31807272},
issn = {2042-8812},
abstract = {Laparoscopic Adjustable Gastric Banding is one of the cardinal bariatric interventions and due to its early safety profile, became the mainstay. Major long-term complications of gastric banding include pouch-herniation-dilation and gastric erosion. A 59-year-old female presented to the emergency department with a 2-week history of progressive central abdominal pain and distention on a background history of a laparoscopic adjustable band insertion 11 years previously. Subsequent computed tomography demonstrated an intragastric band erosion. An exploratory laparotomy demonstrated a gastric band eroded through the stomach sealed by a biofilm. Secondary findings included small bowel ischemia and portal vein thrombosis. The gastric band was extracted, and the stomach was repaired. The ischemic small bowel was resected with primary anastomosis. The patient recovered uneventfully. Gastric band erosion should be considered in all patients presenting with abdominal pain and previous weight loss surgery. Prompt recognition may avoid fatal consequences.},
}
@article {pmid31806326,
year = {2019},
author = {Zhou, H and Xu, G},
title = {Biofilm characteristics, microbial community structure and function of an up-flow anaerobic filter-biological aerated filter (UAF-BAF) driven by COD/N ratio.},
journal = {The Science of the total environment},
volume = {},
number = {},
pages = {134422},
doi = {10.1016/j.scitotenv.2019.134422},
pmid = {31806326},
issn = {1879-1026},
abstract = {The biofilm characteristics, microbial community structure and function in a lab-scale up-flow anaerobic filter-biological aerated filter (UAF-BAF) driven by COD/N ratio were investigated. Results showed that the TN removal rate of system reduced from 68.7% to 50.6% with COD/N ratio ranging from 10 to 3. Biofilm characteristics analysis indicated that the biomass, biofilm thickness, polysaccharide and protein contents in extracellular polymeric substance and dehydrogenase activity from biofilm in the UAF-BAF declined with the decrease of COD/N ratio. The biofilm structure visualized by confocal laser scanning microscopy displayed that the total cells and EPS content decreased as the COD/N ratio downshifted. 16S rRNA sequencing illustrated that Zoogloea and Pleomorphomonas were the major contributors to TN removal in the UAF, with dramatically decreasing abundance. Functional prediction indicated that the genes involved in nitrogen metabolism and nitrate reductase (EC 1.7.99.4) also decreased, which was responsible for the decrease of TN removal. This study provided insights into understanding of the biofilm structure and underlying ecological function in the UAF-BAF, which would help to regulate wastewater biofilm and improve process performance.},
}
@article {pmid31806298,
year = {2019},
author = {Jing, X and Yang, Y and Ai, Z and Chen, S and Zhou, S},
title = {Potassium channel blocker inhibits the formation and electroactivity of Geobacter biofilm.},
journal = {The Science of the total environment},
volume = {},
number = {},
pages = {135796},
doi = {10.1016/j.scitotenv.2019.135796},
pmid = {31806298},
issn = {1879-1026},
abstract = {Bacteria in biofilms are able to utilize potassium ion channel-mediated electrical signaling to achieve cell-cell communication. However, it remains unclear whether these signals play a role in Geobacter sp. when surrounded by an intense electric field. This study used a potassium channel blocker (tetraethylammonium, TEA) that interfered with the release of K+ but not bacterial growth to demonstrate that potassium ion channel-mediated electrical signaling affected the formation and electroactivity of Geobacter sulfurreducens. The results showed that 5 mM TEA slowed the formation of Geobacter sulfurreducens biofilm, and the current density was ~50% lower than in the control. The electrochemical analyses showed that the electroactivity of the biofilms with TEA addition was inferior. In particular, the micrometer- scale biofilm with TEA exhibited fewer high current peaks, and the species of outermost groups that participated in the electron transfer in Geobacter sulfurreducens biofilms was different from the control. This work provides initial evidence to reveal the role of potassium channels in Geobacter sulfurreducens electroactive biofilms.},
}
@article {pmid31805997,
year = {2019},
author = {Davari Abad, E and Khameneh, A and Vahedi, L},
title = {Identification phenotypic and genotypic characterization of biofilm formation in Escherichia coli isolated from urinary tract infections and their antibiotics resistance.},
journal = {BMC research notes},
volume = {12},
number = {1},
pages = {796},
pmid = {31805997},
issn = {1756-0500},
abstract = {OBJECTIVE: Urinary tract infections (UTIs) are the most common infectious diseases, and Escherichia coli is the most common pathogen isolated from patients with UTIs. The products of sfa, afa and foc genes are important for binding of the bacterium to urinary tract epithelium. Our aim was to investigate these genes in E. colis isolated from patients with UTIS. The frequencies of the genes were determined using PCR. Biofilm formation and antibiotic resistance rates were determined using microtiter plate and disk diffusion methods, respectively. The P < 0.05 was considered statistically significant.<br><br>RESULTS: The frequencies of sfa, afa and foc were 75.3%, 17.5% and 22.5%, respectively showing a significantly higher prevalence of the sfa gene. The most effective antibiotics against the E. colis were nitrofurantoin and amikacin. The highest microbial resistance rates were also observed against amoxicillin and ampicillin. Furthermore, 12.7%, 6.3%, 74.7% and 6.3% of the isolates showed strong, moderate, weak capacities and no connections to form biofilms, respectively. The expression of the sfa gene was significantly associated with forming strong biofilms. Regarding the variabilities in the characteristics of E. coli strains associated with UTIs, it seems reasonable to adjust diagnostic and therapeutic methods according to the regional microbial characteristics.},
}
@article {pmid31805825,
year = {2019},
author = {Cramer, M and Schelhorn, P and Kotzbauer, U and Tränckner, J},
title = {Degradation kinetics and COD fractioning of agricultural wastewaters from biogas plants applying biofilm respirometry.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-11},
doi = {10.1080/09593330.2019.1701570},
pmid = {31805825},
issn = {1479-487X},
abstract = {Stormwater runoff from agricultural silo facilities can be heavily polluted and needs to be treated before discharged. This study investigates biological treatability and kinetic constants of characteristic silo runoffs, applying attached growth systems. For this, respirometry measurements, typically applied in the activated sludge systems (ASM) as a suspended growth, were modified by using adapted biofilm carriers. This allows a determination of degradation kinetic of the biofilm system and a COD fractioning at the same time, which are fundamental values for the design of a full-scale plant. The developed respirometry method was compared with the state-of-the-art method using suspended growth systems and domestic wastewater. Results are comparable with the parameter of the ASM. As stormwater runoff is usually a mixture from different pollution sources, various, typically occurring substrates are investigated regarding degradation kinetics and COD fractions. Wastewater polluted with digestion residue and solid manure showed similar COD fractions as domestic wastewater with an inert fraction Si of 5-6% and a comparatively low rapidly degradable fraction SS of 21-27%. However, wastewater from corn or whole crop silage showed significant better degradation efficiencies and kinetics with an Si of 2-3% and a rapidly degradable fraction of 56-57%. As COD concentrations up to 5000 mg L-1 for stormwater runoff and up to 60,000 mg L-1 for silage effluent can be expected, the results not only show the necessity but also prove the feasibility of biological treatment of stormwater runoff from silo works and provide design parameters for adapted treatment systems.},
}
@article {pmid31805672,
year = {2019},
author = {Beklen, A and Torittu, A and Ihalin, R and Pöllänen, M},
title = {Aggregatibacter actinomycetemcomitans Biofilm Reduces Gingival Epithelial Cell Keratin Expression in an Organotypic Gingival Tissue Culture Model.},
journal = {Pathogens (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/pathogens8040278},
pmid = {31805672},
issn = {2076-0817},
support = {126557, 265609, and 272960//Academy of Finland/ ; N/A//The Scientific and Technological Research Council of Turkey (TUBITAK)/ ; },
abstract = {Epithelial cells express keratins, which are essential for the structural integrity and mechanical strength of the cells. In the junctional epithelium (JE) of the tooth, keratins such as K16, K18, and K19, are expressed, which is typical for non-differentiated and rapidly dividing cells. The expression of K17, K4, and K13 keratins can be induced by injury, bacterial irritation, smoking, and inflammation. In addition, these keratins can be found in the sulcular epithelium and in the JE. Our aim was to estimate the changes in K4, K13, K17, and K19 expression in gingival epithelial cells exposed to Aggregatibacter actinomycetemcomitans. An organotypic gingival mucosa and biofilm co-culture was used as a model system. The effect of the biofilm after 24 h was assessed using immunohistochemistry. The structure of the epithelium was also studied with transmission electron microscopy (TEM). The expression of K17 and K19, as well as total keratin expression, decreased in the suprabasal layers of epithelium, which were in close contact with the A. actinomycetemcomitans biofilm. The effect on keratin expression was biofilm specific. The expression of K4 and K13 was low in all of the tested conditions. When stimulated with the A. actinomycetemcomitans biofilm, the epithelial contact site displayed a thick necrotic layer on the top of the epithelium. The A. actinomycetemcomitans biofilm released vesicles, which were found in close contact with the epithelium. After A. actinomycetemcomitans irritation, gingival epithelial cells may lose their resistance and become more vulnerable to bacterial infection.},
}
@article {pmid31805671,
year = {2019},
author = {Desai, S and Sanghrajka, K and Gajjar, D},
title = {High Adhesion and Increased Cell Death Contribute to Strong Biofilm Formation in Klebsiellapneumoniae.},
journal = {Pathogens (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/pathogens8040277},
pmid = {31805671},
issn = {2076-0817},
abstract = {Klebsiella pneumoniae (Kp), is a frequent cause of hospital and community-acquired infections and WHO had declared it as a &quot;priority pathogen&quot;. Biofilm is a major virulence factor of Kp and yet the mechanism of strong biofilm formation in Kp is unclear. A key objective of the present study is to investigate the differences between strong and weak biofilms formed by clinical isolates of Kp on various catheters and in different media conditions and to identify constituents contributing to strong biofilm formation. Quantification of matrix components (extracellular DNA (eDNA), protein, exopolysaccharides (EPS), and bacterial cells), confocal laser scanning microscopy (CLSM), field emission gun scanning electron microscopy (FEG-SEM) and flow-cytometry analysis were performed to compare strong and weak biofilm matrix. Our results suggest increased biofilm formation on latex catheters compared to silicone and silicone-coated latex catheters. Higher amounts of eDNA, protein, EPS, and dead cells were observed in the strong biofilm of Kp. High adhesion capacity and cell death seem to play a major role in formation of strong Kp biofilms. The enhanced eDNA, EPS, and protein in the biofilm matrix appear as a consequence of increased cell death.},
}
@article {pmid31800863,
year = {2019},
author = {Fidalgo, TKDS and Americano, G and Medina, D and Athayde, G and Letieri, ADS and Maia, LC},
title = {Adhesiveness of bulk-fill composite resin in permanent molars submitted to Streptococcus mutans biofilm.},
journal = {Brazilian oral research},
volume = {33},
number = {},
pages = {e111},
doi = {10.1590/1807-3107bor-2019.vol33.0111},
pmid = {31800863},
issn = {1807-3107},
mesh = {Adhesiveness ; Biofilms/*drug effects ; Composite Resins/*chemistry ; Dental Bonding/*methods ; Dental Caries ; Dental Enamel/drug effects ; Dental Leakage ; Dental Restoration, Permanent/methods ; Humans ; Materials Testing ; Reproducibility of Results ; Statistics, Nonparametric ; Streptococcus mutans/*drug effects ; Surface Properties ; Tensile Strength/drug effects ; Time Factors ; },
abstract = {The aim of the present study was to evaluate the microtensile bond strength and the microleakage of a bulk-fill composite resin compared with a conventional incremental composite resin, in permanent molars and under cariogenic challenge using a Streptococcus mutans model. Permanent human third molars (n = 60) with an occlusal cavity of 5×3×2 mm were randomly allocated into four subgroups of restorative treatments: conventional composite resin with (n = 15) and without (n = 15) cariogenic challenge (Z350-E and Z350-C experimental and control groups, respectively), and bulk-fill composite resin with (n = 15) and without (n = 15) cariogenic challenge (Bulk Fill-E and Bulk Fill-C, respectively). Ten specimens from each subgroup were submitted to microtensile strength, and 5, to microleakage. The cariogenic challenge was conducted using the Streptococcus mutans strain (ATCC) for 7 days. The stickers obtained (1 × 1 × 2 mm) were submitted to a microtensile strength test, followed by classification of the fracture mode. Microleakage was performed using a scoring system. The data were analyzed by Kruskal-Wallis and Mann-Whitney tests (p < 0.05). Filtek Z350 XT resin presented higher microtensile bond strength than Bulk Fill resin without (19.02 ± 4.90 and 8.76 ± 3.94MPa, respectively; p < 0.001) and with cariogenic challenge (22.69 ± 7.86 and 13.31 ± 3.38MPa, respectively; p < 0.02). Z350-C and Bulk Fill-C resins presented a higher prevalence of mixed fractures (23 and 14%, respectively) in the specimens submitted to cariogenic challenge than those of the control groups, whereas microleakage was similar (p = 0.85). The conventional composite resin had higher microtensile bond strength than the bulk-fill resin, but both resin types had similar adhesion quality and microfiltration scores.},
}
@article {pmid31799432,
year = {2019},
author = {Suleiman, M and Schröder, C and Kuhn, M and Simon, A and Stahl, A and Frerichs, H and Antranikian, G},
title = {Microbial biofilm formation and degradation of octocrylene, a UV absorber found in sunscreen.},
journal = {Communications biology},
volume = {2},
number = {},
pages = {430},
pmid = {31799432},
issn = {2399-3642},
abstract = {Octocrylene is a widely used synthetic UV absorber of sunscreens and found in several environments. Ecological consequences of the accumulation of UV filters are widely discussed. This is the first report revealing the microbial potential to transform octocrylene. A microbial community comprising four bacterial species was enriched from a landfill site using octocrylene as carbon source. From these microorganisms Mycobacterium agri and Gordonia cholesterolivorans were identified as most potent applying a new &quot;reverse discovery&quot; approach. This relies on the possibility that efficient strains that are already isolated and deposited can be identified through enrichment cultures. These strains formed massive biofilms on the octocrylene droplets. GC-MS analysis after cultivation for 10 days with M. agri revealed a decrease in octocrylene concentration of 19.1%. LC-MS/MS analysis was utilized in the detection and quantification of transformation products of octocrylene. M. agri thus represents an ideal candidate for bioremediation studies with octocrylene and related compounds.},
}
@article {pmid31798802,
year = {2018},
author = {Kıvanç, SA and Arık, G and Akova-Budak, B and Kıvanç, M},
title = {Biofilm forming capacity and antibiotic susceptibility of Staphylococcus spp. with the icaA/icaD/bap genotype isolated from ocular surface of patients with diabetes.},
journal = {Malawi medical journal : the journal of Medical Association of Malawi},
volume = {30},
number = {4},
pages = {243-249},
doi = {10.4314/mmj.v30i4.6},
pmid = {31798802},
issn = {1995-7270},
mesh = {Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/genetics ; Biofilms/*growth &amp; development ; Diabetes Complications/epidemiology ; Diabetes Mellitus/epidemiology ; Drug Resistance, Bacterial ; Eye Infections, Bacterial/*microbiology ; Genes, Bacterial/genetics/physiology ; Genotype ; Humans ; Microbial Sensitivity Tests ; Microscopy, Electron, Scanning ; Phenotype ; Polymerase Chain Reaction ; Retrospective Studies ; Staphylococcal Infections/diagnosis/*microbiology ; Staphylococcus/*drug effects/genetics/isolation &amp; purification ; },
abstract = {Introduction: Bacterial biofilm is an exopolysaccharide matrix that is produced by bacteria while they adhere on abiotic or biotic surfaces. The bacteria living in this matrix are more resistant to antibiotics than planctonic bacteria. The biofilm formation property of the bacteria is determined by genes; and this is related to virulence of the microorganism. In ophthalmology, biofilms form especially on abiotic surfaces such as silicon tubes, contact lenses, intraocular lenses etc.<br><br>Aim: Our aim was to investigate genotypic and phenotypic structures of biofilms that are produced by Staphylococcus spp., which was obtained from the eyes of diabetic patients and determine the effect on antibiotic susceptibility.<br><br>Methods: The study group was comprised with 83 isolates from diabetic patients and 21 isolates from non-diabetic patients. Presumptive isolates were detected and confirmed by a microbial identification system VITEK II. Automated EcoRI Ribotyping was performed. Biofilm production was detected by Congo Red Agar Plate and Microtiter Plate Assay. Disc diffusion method was used for determination of antibiotic susceptibility of isolates.<br><br>Results: Out of the 83 isolates from diabetic patients, 25 were weakly (30%), 20 were moderately (24%), and 25 were strongly (30%) biofilm positive. Seven isolates of S. aureus, 11 isolates of S.epidermidis, 2 isolates of S. warneri, 3 isolates of S.hominis, and 2 isolates of S.lugdunensis were identified as strong biofilm producers. Out of the 83 Staphylococcus isolates, 37 were cefuroxime, 18 ciprofloxacin, 11 vancomycin, 12 gatifloxacin, and 18 moxifloxacin resistant. In total, 37 strains were resistant to three or more antibiotics. There was a statistically significant relation between biofilm formation and multidrug resistance (against three or more antibiotics, p<0.001). In nondiabetic patients, 15(71%) isolates were non adherent or weakly adherent, and 2(10%) were strongly adherent biofilm positive.<br><br>Conclusion: In conclusion, bacterial conjunctival flora of patients with diabetes is likely to produce biofilm. Biofilm formation is associated with multidrug rsistance in patients with diabetes.},
}
@article {pmid31798554,
year = {2019},
author = {Soares, A and Roussel, V and Pestel-Caron, M and Barreau, M and Caron, F and Bouffartigues, E and Chevalier, S and Etienne, M},
title = {Understanding Ciprofloxacin Failure in Pseudomonas aeruginosa Biofilm: Persister Cells Survive Matrix Disruption.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2603},
doi = {10.3389/fmicb.2019.02603},
pmid = {31798554},
issn = {1664-302X},
abstract = {Biofilms are commonly recalcitrant to antibiotics, through incompletely elucidated mechanisms such as tolerance and persistence. We aimed at investigating how a Pseudomonas aeruginosa biofilm escapes ciprofloxacin treatment. P. aeruginosa PA14 in vitro mature biofilms were challenged with supra-MIC ciprofloxacin concentrations. Cell viability was quantified by fluorescein diacetate assay. Population dynamics were determined by counts of surviving culturable cells. Biofilms were analyzed using confocal laser scanning microscopy (CLSM), and the expression of genes involved in stringent response, toxin-antitoxin HigB/HigA, and type 3 secretion system (T3SS) was quantified by RT-qPCR in untreated and treated biofilms. Ciprofloxacin exposure resulted in an initial reduction of bacterial counts following a biphasic time-kill curve. After 24 h of treatment, the overall cell activity and the density of culturable cells significantly decreased as compared to untreated biofilm. No resistant mutant was isolated among the <1% surviving cells. Phenotypic adaptation toward persistence appeared to start after only 1 h of antibiotic exposure, by an overexpression of the genes involved in stringent response and in the toxin-antitoxin system, whereas the expression of genes encoding for the T3SS remained unchanged. After 4 h of ciprofloxacin exposure, stringent response genes returned to their basal level of expression. After a prolonged ciprofloxacin exposure, a deep alteration in the matrix structure that became thinner and lost mushroom-like aggregates was observed, in relation with reduced biovolumes of exopolysaccharides and extracellular DNA. These results support that ciprofloxacin might first induce the bacterial killing of most bacterial cells, but simultaneously activate stringent response mechanisms contributing to the switch of a subpopulation toward a persister phenotype. Once the persister phenotype is expressed, and despite an unexpected alteration of the biofilm matrix, ciprofloxacin fails to eradicate biofilm.},
}
@article {pmid31797835,
year = {2019},
author = {Thomas, AR and Mani, R and Reddy, TV and Ravichandran, A and Sivakumar, M and Krishnakumar, S},
title = {Evaluation of the Antibacterial Efficiency of a Combination of 1% Alexidine and Sodium Hypochlorite on Enterococcus faecalis Biofilm Models: An In Vitro Study.},
journal = {The journal of contemporary dental practice},
volume = {20},
number = {9},
pages = {1090-1094},
pmid = {31797835},
issn = {1526-3711},
mesh = {Anti-Bacterial Agents ; Biguanides ; Biofilms ; Dentin ; *Enterococcus faecalis ; Humans ; India ; Microscopy, Confocal ; Root Canal Irrigants ; *Sodium Hypochlorite ; },
abstract = {AIM: The aim of the study was to assess the antibacterial efficiency of a combination of 1% alexidine (ALX) and 5.25% sodium hypochlorite (NaOCl) against E. faecalis biofilm using a confocal scanning electron microscopy.<br><br>MATERIALS AND METHODS: An estimated 120 human root dentin disks were prepared, sterilized, and inoculated with E. faecalis strain (ATCC 29212) to develop a 3-weeks-old biofilm. The dentin discs were exposed to group I-control group: 5.25% sodium hypochlorite (NaOCl) (n = 20); group II-1% ALX + 5.25% NaOCl (n = 40); group III-1% alexidine (ALX) (n = 40) (Sigma-Aldrich, Mumbai, India); group IV-negative control: saline (n = 20). After exposure, the dentin disks were stained with the fluorescent live/dead dye and evaluated with a confocal scanning electron microscope to calculate the proportion of dead cells. Statistical analysis was done using the Kruskal-Wallis and Mann-Whitney U test (p < 0.05).<br><br>RESULTS: The maximum proportion of dead cells were seen in the groups treated with the combination of 1% ALX + 5.25% NaOCl (94.89%) and in the control group 5.25% NaOCl (93.14%). The proportion of dead cells presented in the 1% ALX group (51.79%) and negative control group saline (15.10%) were comparatively less.<br><br>CONCLUSION: The antibacterial efficiency of a combination of 1% ALX and 5.25% NaOCl was more effective when compared with 1% ALX alone.<br><br>CLINICAL SIGNIFICANCE: Alexidine at 1% could be used as an alternative endodontic irrigant to chlorhexidine, as alexidine does not form any toxic precipitates with sodium hypochlorite. The disinfection regimen comprising a combination of 1% ALX and 5.25% NaOCl is effective in eliminating E. faecalis biofilms.},
}
@article {pmid31797512,
year = {2019},
author = {Wettstadt, S},
title = {Breaking free from home: biofilm dispersal by a glycosidase from Desulfovibrio vulgaris.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.14883},
pmid = {31797512},
issn = {1462-2920},
support = {BIO2017-83763-P//Consejo Superior de Investigaciones Científicas/ ; },
}
@article {pmid31797056,
year = {2019},
author = {Cao, Y and Yin, H and Wang, W and Pei, P and Wang, Y and Wang, X and Jiang, J and Luo, SZ and Chen, L},
title = {Killing Streptococcus mutans in mature biofilm with a combination of antimicrobial and antibiofilm peptides.},
journal = {Amino acids},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00726-019-02804-4},
pmid = {31797056},
issn = {1438-2199},
support = {PYBZ1812//Research projects on biomedical transformation of China-Japan Friendship Hospital/ ; PYBZ1815//Research projects on biomedical transformation of China-Japan Friendship Hospital/ ; 2017YFF0205402//National Key Research and Development Program/ ; 21562035//National Natural Science Foundation of China/ ; 21672019//National Natural Science Foundation of China/ ; 21402006//National Natural Science Foundation of China/ ; 91853116//National Natural Science Foundation of China/ ; XK1802-8//Fundamental Research Funds for the Central Universities/ ; PYBZ1711//Fundamental Research Funds for the Central Universities/ ; ZZ1702//Fundamental Research Funds for the Central Universities/ ; XK1701//Fundamental Research Funds for the Central Universities/ ; },
abstract = {Biofilm poses a serious challenge for the treatment of bacterial infections, as it endows bacteria a pronounced resistance to traditional antibiotics. Antimicrobial peptides (AMPs) are considered potential substitutes for antibiotics. Combinational use of AMPs with other compounds to exert antibiofilm effects has been proved to be an effective means to reduce their toxicity and maximize their antimicrobial activity. However, the combination of various AMPs with different action mechanisms is rarely investigated. A newly designed lytic AMP ZXR-2.3 combined with antibiofilm peptide IDR-1018 or KT2 was tested for the antibiofilm effect on mature Streptococcus mutans biofilms. In general, the combination of ZXR-2.3 + IDR-1018 displayed synergistic effect on both biofilm eradication and bacterial killing, while ZXR-2.3 + KT2 showed no obvious synergism. The confocal images of preformed S. mutans biofilms confirmed the effective bactericidal activity of ZXR-2.3 + IDR-1018. A tube system was applied to investigate the biofilm infection under a flow of medium and SEM images indicated the biofilm disruption and bacterial killing effects of ZXR-2.3 + IDR-1018. Quantitative RT-PCR analysis showed that IDR-1018 induced dramatic changes in the mRNA expressions of the quorum sensing (QS) related genes comC, comD, vicR, and vicK of S. mutans in mature biofilms, whereas the other peptides and ciprofloxacin did not cause obvious changes in these genes. This might explain the better synergism of ZXR-2.3 and IDR-1018. The results of this study provide a potential application using the combination of different AMPs in the treatment of mature biofilm infection.},
}
@article {pmid31796849,
year = {2019},
author = {Whelan, MVX and Ardill, L and Koide, K and Nakajima, C and Suzuki, Y and Simpson, JC and Ó Cróinín, T},
title = {Acquisition of fluoroquinolone resistance leads to increased biofilm formation and pathogenicity in Campylobacter jejuni.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {18216},
doi = {10.1038/s41598-019-54620-1},
pmid = {31796849},
issn = {2045-2322},
support = {105343/Z/14/Z//Wellcome Trust (Wellcome)/ ; },
abstract = {The World Health Organization has listed C. jejuni as one of 12 microorganisms on a global priority list for antibiotic resistance due to a rapid increase in strains resistant to fluoroquinolone antibiotics. This fluoroquinolone resistance is conferred through a single point mutation in the QRDR region within the gyrA gene known to be involved in DNA supercoiling. We have previously revealed that changes in DNA supercoilikng play a major role in the regulation of virulence in C. jejuni with relaxation of DNA supercoiling associated with increased attachment to and invasion of human epithelial cells. The aim of this study was to investigate whether fluoroquinolone resistant strains of C. jejuni displayed altered supercoiling associated phenotypes. A panel of fluoroquinolone resistant mutants were derived and shown to have a greater ability to form viable biofilms under aerobic conditions, invade epithelial cells and promote virulence in the Galleria mellonella model of infection. We thus report for the first time that fluoroquinolone resistance in C. jejuni is associated with an increase in virulence and the ability to form viable biofilms in oxygen rich environments. These altered phenotypes likely play a critical role in the continued increase in fluoroquinolone resistance observed for this important pathogen.},
}
@article {pmid31794939,
year = {2019},
author = {Wang, J and Liu, Q and Li, X and Ma, S and Hu, H and Wu, B and Zhang, XX and Ren, H},
title = {In-situ monitoring AHL-mediated quorum-sensing regulation of the initial phase of wastewater biofilm formation.},
journal = {Environment international},
volume = {135},
number = {},
pages = {105326},
doi = {10.1016/j.envint.2019.105326},
pmid = {31794939},
issn = {1873-6750},
abstract = {Initial attachment plays an important role in biofilm formation in wastewater treatment processes. However, the initial attachment process mediated by N-acyl-homoserine lactones (AHLs) is difficult to be fully understood due to the lack of non-invasive and on-line investigation techniques. In this study, the AHL-regulated wastewater biofilm attachment was quantified using ultrasonic time-domain reflectometry (UTDR) as an in-situ and non-invasive monitoring technique. Results demonstrated that the reversible adhesion time in municipal and industrial wastewaters was significantly decreased in the presence of exogenous AHLs. Biofilm thickness in municipal and industrial wastewaters increased significantly with the addition of exogenous AHLs. Also, the addition of acylase delayed the initial biofilm formation (lengthened reversible adhesion time and decreased biofilm thickness and density). Compared with biofilm behavior in the presence of low concentrations of AHLs (4.92 ± 0.17 μg/L), both reversible adhesion time and biofilm thickness were not significantly increased (p > 0.05) with an increase in AHL concentration (9.75 ± 0.41 μg/L). Furthermore, the addition of exogenous AHLs resulted in significant changes in the attached bacterial community structures, in which both QS and quorum-quenching (QQ) bacteria were stimulated. The current work presents an effective approach to in-situ monitoring of the regulation of AHL-mediated QS in the initial attachment of biofilms, especially in the reversible adhesion process, which may provide a potential strategy to facilitate biofilm establishment in wastewater treatment processes.},
}
@article {pmid31794255,
year = {2019},
author = {Wang, W and Wang, L and Su, J and Xu, Z},
title = {Antibiotic Susceptibility, Biofilm-Forming Ability, and Incidence of Class 1 Integron of Salmonella spp., Escherichia coli, and Staphylococcus aureus Isolated from Various Foods in a School Canteen in China.},
journal = {Foodborne pathogens and disease},
volume = {},
number = {},
pages = {},
doi = {10.1089/fpd.2019.2694},
pmid = {31794255},
issn = {1556-7125},
abstract = {In recent years, the food poisoning incidents from school canteens have aroused widespread concern in China. Microbial contamination to the foods is the main factor responsible for these food poisoning events. In this study, identification of microbial pathogens including Salmonella spp., Escherichia coli, and Staphylococcus aureus in samples (frozen pork, fresh pork, fresh chicken, and different fresh vegetables) of a school canteen in China during 2017 to 2018 was performed. The antibiotic susceptibility pattern, class 1 integron, and biofilm formation ability of the isolated pathogens were also investigated. In total, 96 strains were isolated (32 Salmonella spp., 32 E. coli, and 32 S. aureus). The antibiogram study results demonstrated that 61.5% strains were found resistant to at least one type of antibiotics, and 17.7% were resistant to three or more antibiotics. In addition, 31.3% strains possessed class 1 integron. Among the integron-positive isolates, 38.9% Salmonella spp. and 87.5% E. coli contained ∼800 or/and 1500 bp size gene cassette within the integrons. However, four S. aureus strains possessing class 1 integron without gene cassette were found. Although none of the isolated strains were found strong biofilm producer, 44.8% were found to have weak or moderate biofilm formation ability. Despite biofilm formation ability or not, the Salmonella spp. containing positive class 1 integron showed significant resistance to cefazolin and gentamicin. In addition, class 1 integron-positive E. coli isolates having the biofilm formation ability hardly showed sensitive to four antibiotics, such as amikacin, amoxicillin-clavulanate, cefazolin, and gentamicin. Therefore, it is necessary to reduce the prevalence of antibiotic resistance gene cassettes containing antibiotic resistance genes by the prudent use of antibiotics in livestock farms, and the improvement of food processing and storage environment.},
}
@article {pmid31790796,
year = {2019},
author = {Ghosh, C and Bhowmik, J and Ghosh, R and Das, MC and Sandhu, P and Kumari, M and Acharjee, S and Daware, AV and Akhter, Y and Banerjee, B and De, UC and Bhattacharjee, S},
title = {The anti-biofilm potential of triterpenoids isolated from Sarcochlamys pulcherrima (Roxb.) Gaud.},
journal = {Microbial pathogenesis},
volume = {139},
number = {},
pages = {103901},
doi = {10.1016/j.micpath.2019.103901},
pmid = {31790796},
issn = {1096-1208},
abstract = {Formation of biofilm is the major cause of Pseudomonas aeruginosa associated pathological manifestations in the urinary tract, respiratory system, gastrointestinal tract, skin, soft tissues etc. Triterpenoid group of compounds have shown their potential in reducing planktonic and biofilm form of bacteria. Sarcochlamys pulcherrima (Roxb.) Gaud. is an ethnomedicinal plant traditionally used for its anti-microbial and anti-inflammatory property. In the present study two triterpenoids, have been isolated from this plant, characterised and evaluated for their antibacterial and antibiofilm potential against P. aeruginosa. Compounds were characterised as 2α, 3β, 19α-trihydroxy-urs-12-ene-28-oic acid (Tormentic acid) and 2α, 3β, 23-trihydroxyurs-12-ene-28-oic acid (23-hydroxycorosolic acid) through spectroscopic studies viz. infrared (IR), nuclear magnetic resonance (NMR) and mass spectroscopy (MS). Depolarization of bacterial membrane and zone of inhibition studies revealed that both the compounds inhibited the growth of planktonic bacteria. Compounds were also found to inhibit the formation of P. aeruginosa biofilm. Inhibition of biofilm found to be mediated through suppressed secretion of pyoverdin, protease and swarming motility of P. aeruginosa. Gene expression study, in silico binding analysis, in vivo bacterial load and tissue histology observations also supported the antibiofilm activity of both the compounds. In vitro and in vivo study showed that both compounds were non-toxic. The study has explored the antibacterial and antibiofilm effect of two triterpenes isolated for the first time from S. pulcherrima.},
}
@article {pmid31790395,
year = {2019},
author = {Hegde, S and Nilyanimit, P and Kozlova, E and Anderson, ER and Narra, HP and Sahni, SK and Heinz, E and Hughes, GL},
title = {CRISPR/Cas9-mediated gene deletion of the ompA gene in symbiotic Cedecea neteri impairs biofilm formation and reduces gut colonization of Aedes aegypti mosquitoes.},
journal = {PLoS neglected tropical diseases},
volume = {13},
number = {12},
pages = {e0007883},
doi = {10.1371/journal.pntd.0007883},
pmid = {31790395},
issn = {1935-2735},
abstract = {BACKGROUND: Symbiotic bacteria are pervasive in mosquitoes and their presence can influence many host phenotypes that affect vectoral capacity. While it is evident that environmental and host genetic factors contribute in shaping the microbiome of mosquitoes, we have a poor understanding regarding how bacterial genetics affects colonization of the mosquito gut. The CRISPR/Cas9 gene editing system is a powerful tool to alter bacterial genomes facilitating investigations into host-microbe interactions but has yet to be applied to insect symbionts.<br><br>To investigate the role of bacterial genetic factors in mosquito biology and in colonization of mosquitoes we used CRISPR/Cas9 gene editing system to mutate the outer membrane protein A (ompA) gene of a Cedecea neteri symbiont isolated from Aedes mosquitoes. The ompA mutant had an impaired ability to form biofilms and poorly infected Ae. aegypti when reared in a mono-association under gnotobiotic conditions. In adult mosquitoes, the mutant had a significantly reduced infection prevalence compared to the wild type or complement strains, while no differences in prevalence were seen in larvae, suggesting genetic factors are particularly important for adult gut colonization. We also used the CRISPR/Cas9 system to integrate genes (antibiotic resistance and fluorescent markers) into the symbionts genome and demonstrated that these genes were functional in vitro and in vivo.<br><br>CONCLUSIONS/SIGNIFICANCE: Our results shed insights into the role of ompA gene in host-microbe interactions in Ae. aegypti and confirm that CRISPR/Cas9 gene editing can be employed for genetic manipulation of non-model gut microbes. The ability to use this technology for site-specific integration of genes into the symbiont will facilitate the development of paratransgenic control strategies to interfere with arboviral pathogens such Chikungunya, dengue, Zika and Yellow fever viruses transmitted by Aedes mosquitoes.},
}
@article {pmid31788680,
year = {2019},
author = {Patenall, BL and Williams, GT and Gwynne, L and Stephens, LJ and Lampard, EV and Hathaway, HJ and Thet, NT and Young, AE and Sutton, MJ and Short, RD and Bull, SD and James, TD and Sedgwick, AC and Jenkins, ATA},
title = {Reaction-based indicator displacement assay (RIA) for the development of a triggered release system capable of biofilm inhibition.},
journal = {Chemical communications (Cambridge, England)},
volume = {55},
number = {100},
pages = {15129-15132},
doi = {10.1039/c9cc07759f},
pmid = {31788680},
issn = {1364-548X},
mesh = {Anthraquinones/*chemistry/pharmacology ; Anti-Bacterial Agents/chemistry/*pharmacology ; Biofilms/*drug effects ; Escherichia coli/drug effects ; Hydrogels/chemistry/pharmacology ; Hydrogen Peroxide/*chemistry ; Methicillin-Resistant Staphylococcus aureus/*physiology ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/drug effects ; Solubility ; },
abstract = {Here, a reaction-based indicator displacement hydrogel assay (RIA) was developed for the detection of hydrogen peroxide (H2O2) via the oxidative release of the optical reporter Alizarin Red S (ARS). In the presence of H2O2, the RIA system displayed potent biofilm inhibition for Methicillin-resistant Staphylococcus aureus (MRSA), as shown through an in vitro assay quantifying antimicrobial efficacy. This work demonstrated the potential of H2O2-responsive hydrogels containing a covalently bound diol-based drug for controlled drug release.},
}
@article {pmid31787947,
year = {2019},
author = {Chen, P and Wang, JJ and Hong, B and Tan, L and Yan, J and Zhang, Z and Liu, H and Pan, Y and Zhao, Y},
title = {Characterization of Mixed-Species Biofilm Formed by Vibrio parahaemolyticus and Listeria monocytogenes.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2543},
pmid = {31787947},
issn = {1664-302X},
abstract = {Mixed-species biofilms are the predominant form of biofilms found in nature. Research on biofilms have typically concentrated on single species biofilms and this study expands the horizon of biofilm research, where the characterization and dynamic changes of mono and mixed-species biofilms formed by the pathogens, Vibrio parahaemolyticus and Listeria monocytogenes were investigated. Compared to mono-species biofilm, the biomass, bio-volume, and thickness of mixed-species biofilms were significantly lower, which were confirmed using crystal violet staining, confocal laser scanning microscopy and scanning electron microscopy. Further experimental analysis showed these variations might result from the reduction of bacterial numbers, the down-regulation of biofilm-regulated genes and loss of metabolic activity in mixed-species biofilm. In addition, V. parahaemolyticus was located primarily on the surface layers of the mixed-species biofilms thus accruing competitive advantage. This competitive advantage was evidenced in a higher V. parahaemolyticus population density in the mixed-species biofilms. The adhesion to surfaces of the mixed-species biofilms were also reduced due to lower concentrations of extracellular polysaccharide and protein when the structure of the mixed-species was examined using Raman spectral analysis, phenol-sulfuric acid method and Lowry method. Furthermore, the minimum biofilm inhibitory concentration to antibiotics obviously decreased when V. parahaemolyticus co-exited with L. monocytogenes. This study firstly elucidated the interactive behavior in biofilm development of two foodborne pathogens, and future studies for biofilm control and antibiotic therapy should take into account interactions in mixed-species biofilms.},
}
@article {pmid31787943,
year = {2019},
author = {Govaert, M and Smet, C and Walsh, JL and Van Impe, JFM},
title = {Dual-Species Model Biofilm Consisting of Listeria monocytogenes and Salmonella Typhimurium: Development and Inactivation With Cold Atmospheric Plasma (CAP).},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2524},
pmid = {31787943},
issn = {1664-302X},
abstract = {Most environmental biofilms contain a variety of species. These species can establish cooperative and competitive interactions, possibly resulting in an increase or a decrease in antimicrobial resistance. Therefore, results obtained following inactivation of single-species biofilms by means of different technologies (e.g., Cold Atmospheric Plasma, CAP) should be validated for multi-species biofilms. First, a strongly adherent and mature Listeria monocytogenes and S. Typhimurium dual-species biofilm was developed by altering different incubation conditions, i.e., growth medium, incubation temperature, inoculum ratio of L. monocytogenes and S. Typhimurium cells, and incubation time. Adherence and maturity were quantified by means of optical density measurements and viable plate counts, respectively. Secondly, both the (1 day old) reference biofilm and a more mature 7 days old biofilm were treated for different CAP treatment times (0-30 min). Viable plate counts were again used to determine the (remaining) cell density. For both the biofilm development and inactivation, predictive models were applied to describe the growth/inactivation kinetics. Finally, the kinetics of the [1 and 7 day(s) old] dual-species biofilms were compared with those obtained for the corresponding single-species biofilms. Results implied that a strongly adherent and mature reference dual-species biofilm was obtained following 24 h of incubation at 25°C using 20-fold diluted TSB and an inoculum ratio of 1:1. Main observations regarding CAP inactivation were: (i) the dual-species biofilm age had no influence on the CAP efficacy, although a longer treatment time was required for the oldest biofilm, (ii) for the 1 day old biofilms, CAP treatment became less efficient for S. Typhimurium inactivation when this species was part of the dual-species biofilm, while L. monocytogenes inactivation was not influenced by the biofilm type, and (iii) for the 7 days old biofilms, CAP inactivation of both species became more efficient when they were part of the dual-species biofilms. It can be concluded that the efficacy of the CAP treatment is altered when cells become part of a dual-species biofilm, which is quite important with respect to a possible application of CAP for biofilm inactivation within the food industry.},
}
@article {pmid31787937,
year = {2019},
author = {Supa-Amornkul, S and Mongkolsuk, P and Summpunn, P and Chaiyakunvat, P and Navaratdusit, W and Jiarpinitnun, C and Chaturongakul, S},
title = {Alternative Sigma Factor B in Bovine Mastitis-Causing Staphylococcus aureus: Characterization of Its Role in Biofilm Formation, Resistance to Hydrogen Peroxide Stress, Regulon Members.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2493},
pmid = {31787937},
issn = {1664-302X},
abstract = {This study examines treatments of the bacterial pathogen Staphylococcus aureus, namely, in the context of its being a major cause of subclinical bovine mastitis. Such infections caused by S. aureus among dairy cows are difficult to detect and can easily become chronic, leading to reduced productivity and large losses for dairy manufacturers. In this study, the role of alternative sigma factor B (σB), which has been shown to be a global regulator for S. aureus infections, was explored in a mastitis-causing S. aureus strain, RF122. For comparison with the wild-type strain, a sigB null (ΔsigB) mutant was constructed and analyzed for its phenotypes and transcriptome. Our study found that σB is essential for biofilm formation as the ΔsigB mutant strain produced significantly less biofilm than did the wild-type strain at 48 h. σB is involved in response to H2O2 stress. However, σB plays a minor or no role in resistance to antiseptics (e.g., povidone-iodine and chlorhexidine), resistance to tested antibiotics, hemolysin activity, and invasion ability. RNA sequencing identified 225 σB-dependent genes, of which 171 are positively regulated and 54 are negatively regulated. The identified genes are involved in stress response, pathogenesis, and metabolic mechanisms. Quantitative TaqMan RT-PCR was performed to verify the RNA sequencing results; i.e., σB is a positive regulator for asp23, sarA, katA, yabJ, sodA, SAB2006c, and nrdD expressions. In the RF122 strain, σB plays a role in biofilm formation, general stress response (e.g., H2O2), and regulation of virulence factors and virulence-associated genes.},
}
@article {pmid31786395,
year = {2019},
author = {Xu, R and Zhang, S and Meng, F},
title = {Large-sized planktonic bioaggregates possess high biofilm formation potentials: Bacterial succession and assembly in the biofilm metacommunity.},
journal = {Water research},
volume = {170},
number = {},
pages = {115307},
doi = {10.1016/j.watres.2019.115307},
pmid = {31786395},
issn = {1879-2448},
abstract = {Wanted and unwanted surface-attached growth of bacteria is ubiquitous in natural and engineered settings. Normally, attachment of planktonic cells to media surfaces initiates biofilm formation and fundamentally regulates biofilm assembly processes. Here, culturing biofilm with planktonic sludge as source community, we found distinct succession profiles of biofilm communities sourced from the size-fractionated sludge flocs (<25; 25-120; >120 μm). Null model analyses revealed that deterministic process dominated in biofilm community assemblies but decreased with decreasing floc size. Additionally, the relative importance of environmental selection increased with increasing floc size of the source sludge, whereas homogenizing dispersal and ecological drift followed opposite trends. Phylogenetic molecular ecological networks (pMENs) indicated that species interactions were intensive in biofilm microbiota developed from large-sized flocs (>120 μm), as evidenced by the low modularity and harmonic geodesic distance and the high average degree. Intriguingly, the keystone taxa in these biofilm ecological networks were controlled by distinct interaction patterns but all showed strong habitat characteristics (e.g., facultative anaerobic, motile, hydrophobic and involved in extracellular polymeric substance metabolism), corroborating the crucial roles of environmental filtering in structuring biofilm community. Taken together, our findings highlight the role of planktonic floc properties in biofilm community assembly and advance our understanding of microbial ecology in biofilm-based systems.},
}
@article {pmid31786294,
year = {2019},
author = {Jou, IA and Caterino, M and Schnupf, U and Rizzo, R and Cescutti, P and Brady, JW},
title = {Ramachandran conformational energy maps for disaccharide linkages found in Burkholderia multivorans biofilm polysaccharides.},
journal = {International journal of biological macromolecules},
volume = {143},
number = {},
pages = {501-509},
doi = {10.1016/j.ijbiomac.2019.11.037},
pmid = {31786294},
issn = {1879-0003},
abstract = {Ramachandran conformational energy maps have been prepared for all of the glycosidic linkages found in the C1576 exopolysaccharide that constitutes the biofilms of the bacterial species Burkholderia multivorans, a member of the Burkholderia cepacian complex that was isolated from a cystic fibrosis patient. This polysaccharide is a rhamnomannan with a tetrasaccharide repeat unit containing two mannose residues and two rhamnose residues, -[3-α-d-Man-(1→2)-α-d-Man-(1→2)-α-d-Rha-(1→3)-α-d-Rha-(1→]n-, where approximately 50% of the rhamnoses are randomly methylated on their O3 hydroxyl groups, further increasing the overall hydrophobicity of the chains. Because of the methylation, the tetrasaccharide repeat unit actually contains six possible linkages. The conformational energy maps are fully adiabatic relaxed maps in which the energy for each (ϕ,ψ) grid point on the map represents the lowest possible energy for the molecule in that conformation, considering all the combinations of the other degrees of freedom, such as hydroxyl orientations. Molecular dynamics simulations were used to verify that these maps indeed describe the conformational dynamics of these linkages. All six linkages were found to be quite restricted in possible ϕ angles, but to exhibit several possible low-energy ψ angles, suggesting that these chains could be quite flexible.},
}
@article {pmid31785460,
year = {2019},
author = {Abdulgader, M and Yu, QJ and Zinatizadeh, AA and Williams, P and Rahimi, Z},
title = {Performance and kinetics analysis of an aerobic sequencing batch flexible fibre biofilm reactor for milk processing wastewater treatment.},
journal = {Journal of environmental management},
volume = {255},
number = {},
pages = {109793},
doi = {10.1016/j.jenvman.2019.109793},
pmid = {31785460},
issn = {1095-8630},
abstract = {In this study, a sequencing batch flexible fibre biofilm reactor (SB-FFBR) is used for efficient and cost-effective treatment of milk processing wastewater (MPW). The SB-FFBR, modified type of a typical sequencing batch reactor (SBR), is made up of eight bundles of flexible fibre as a supporting media for microorganisms'growth. The working volume and the cycle length of the bioreactor are 8 L and 24 h, respectively. The biological performance of the bioreactor is studied at 10, 3 and 10 various levels of the influent chemical oxygen demand (CODin; 610-8193 mg L-1), retention time (RT; 1, 1.6 and 2 days), and organic loading rate (OLR; 0.38-8.19 gCOD m-3d-1), respectively. From the results, the minimum COD and total suspended solids (TSS) removal efficiency of 86.8% and 77.3% were achieved at OLR of 8.2 kg COD m-3d-1, CODin of 8193 mg L-1 and RT of 1 day. While, an excellent COD and TSS removal efficiency were found to be 97.5% and 99.3%, respectively, at low OLR of 0.4 kg COD m-3d-1, CODin of 945 mg L-1 and RT of 2 days. Furthermore, the kinetic coefficients of COD removal were computed using a first order substrate removal model at different COD concentrations. The first order kinetic constant, (k), was 0.60, 0.65 and 0.357 h-1 for 500, 810 and 2000 mg COD L-1, respectively. The use of the flexible fibre as a packing material provided a huge surface area for more microorganism attachment. Therefore, the results demonstrated the SB-FFBR has acted as a suitable and effective strategy in treatment of milk processing industrial wastewater.},
}
@article {pmid31784952,
year = {2019},
author = {Lee, DH and Kim, BS and Kang, SS},
title = {Bacteriocin of Pediococcus acidilactici HW01 Inhibits Biofilm Formation and Virulence Factor Production by Pseudomonas aeruginosa.},
journal = {Probiotics and antimicrobial proteins},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12602-019-09623-9},
pmid = {31784952},
issn = {1867-1314},
support = {NRF-2017R1D1A1B03028730//National Research Foundation of Korea/ ; },
abstract = {Pseudomonas aeruginosa is a potential source of food contamination that leads to food spoilage and infections as a result of the generation of biofilm and virulence factors. In the present study, we demonstrate that bacteriocin produced by Pediococcus acidilactici HW01 (HW01 bacteriocin) effectively inhibited the biofilm formation of Ps. aeruginosa (66.41, 45.77, and 21.73% of biofilm formation at 0.5, 1, and 2 mg/mL of HW01 bacteriocin, respectively) as well as the production of virulence factors. By means of a microtiter plate method and scanning electron microscopy, HW01 bacteriocin inhibited biofilm formation by Ps. aeruginosa in a dose-dependent manner. Although the viability of biofilm cells of Ps. aeruginosa was reduced in the presence of HW01 bacteriocin, the viability of planktonic cells of Ps. aeruginosa was not affected by HW01 bacteriocin (2.0 × 109 CFU/mL vs. 2.4 × 109 CFU/mL in the absence and the presence of HW01 bacteriocin, respectively). Additionally, HW01 bacteriocin decreased the twitching motility of Ps. aeruginosa as well as the production of virulence factors, such as pyocyanin, protease, and rhamnolipid. Furthermore, HW01 bacteriocin significantly inhibited Ps. aeruginosa biofilm formation on the surface of stainless steel (57% reduction at 24 h and 83% reduction at 72 h). These results indicate that HW01 bacteriocin is an effective antagonist of Ps. aeruginosa as a result of its ability to inhibit biofilm formation and the production of virulence factors.},
}
@article {pmid31784806,
year = {2019},
author = {Fernandes, AWC and Dos Anjos Santos, VL and Araújo, CRM and de Oliveira, HP and da Costa, MM},
title = {Anti-biofilm Effect of β-Lapachone and Lapachol Oxime Against Isolates of Staphylococcus aureus.},
journal = {Current microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00284-019-01818-1},
pmid = {31784806},
issn = {1432-0991},
abstract = {Antimicrobial resistance in bacteria, such as Staphylococcus aureus, has been the subject of many assistance studies of alternatives for the treatment of infections. These studies aim to solve this problem for bacteria, such as biofilm formation. Aiming to control the emergence of the problem or enhance antibiotic activity, the data sources are inserted into new therapeutic alternatives for the treatment of infections. β-Lapachone and Lapachol Oxime are semi-synthetic derivatives of Lapachol with antimicrobial potential. Clinical isolates from human blood cultures were used in this study. Scanning electron microscopy (SEM) was performed following the glutaraldehyde fixation protocol. The presence of β-Lapachone and Lapachol Oxima interfered in the biofilm formation state. In the MEV, the effect was observed in the reduction of the population of biofilm-forming cells. Therefore, it was possible to conclude the promising potential of the anti-biofilm of substances, justifying the nature of the natural products as agents of inspiration for the detection of new compounds with the biological function.},
}
@article {pmid31784584,
year = {2019},
author = {Berditsch, M and Afonin, S and Reuster, J and Lux, H and Schkolin, K and Babii, O and Radchenko, DS and Abdullah, I and William, N and Middel, V and Strähle, U and Nelson, A and Valko, K and Ulrich, AS},
title = {Supreme activity of gramicidin S against resistant, persistent and biofilm cells of staphylococci and enterococci.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {17938},
pmid = {31784584},
issn = {2045-2322},
support = {GRK 2039//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; GRK 2039//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; GRK 2039//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; GRK 2039//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; },
abstract = {Three promising antibacterial peptides were studied with regard to their ability to inhibit the growth and kill the cells of clinical strains of Staphylococcus aureus, Enterococcus faecalis and Enterococcus faecium. The multifunctional gramicidin S (GS) was the most potent, compared to the membranotropic temporin L (TL), being more effective than the innate-defence regulator IDR-1018 (IDR). These activities, compared across 16 strains as minimal bactericidal and minimal inhibitory concentrations (MIC), are independent of bacterial resistance pattern, phenotype variations and/or biofilm-forming potency. For S. aureus strains, complete killing is accomplished by all peptides at 5 × MIC. For E. faecalis strains, only GS exhibits a rapid bactericidal effect at 5 × MIC, while TL and IDR require higher concentrations. The biofilm-preventing activities of all peptides against the six strains with the largest biofilm biomass were compared. GS demonstrates the lowest minimal biofilm inhibiting concentrations, whereas TL and IDR are consistently less effective. In mature biofilms, only GS completely kills the cells of all studied strains. We compare the physicochemical properties, membranolytic activities, model pharmacokinetics and eukaryotic toxicities of the peptides and explain the bactericidal, antipersister and antibiofilm activities of GS by its elevated stability, pronounced cell-penetration ability and effective utilization of multiple modes of antibacterial action.},
}
@article {pmid31784252,
year = {2019},
author = {Zhang, J and Miao, Y and Zhang, Q and Sun, Y and Wu, L and Peng, Y},
title = {Mechanism of stable sewage nitrogen removal in a partial nitrification-anammox biofilm system at low temperatures: Microbial community and EPS analysis.},
journal = {Bioresource technology},
volume = {},
number = {},
pages = {122459},
doi = {10.1016/j.biortech.2019.122459},
pmid = {31784252},
issn = {1873-2976},
abstract = {Stable sewage nitrogen removal with nitrogen removal efficiency of 87.5 ± 2.2% was achieved in a partial nitrification-anammox (PNA) biofilm system at low temperatures (12.8-16.3 °C). High-throughput sequencing analysis indicated that the microbial community structure in the sequencing batch biofilm reactor (SBBR) remained reasonably stable. Candidatus Brocadia was the only detected anammox genus and remained stable at 0.3-0.5%. Some psychrotolerant microorganisms that could secrete cryoprotective extracellular polymeric substances (EPS), including Flavobacterium and Thermomonas, were enriched at low temperatures. This could be conducive to the stable operation of the PNA-SBBR. Moreover, according to the EPS composition and characteristics analysis, the secretion of tightly-bound EPS that bound to the cell surface containing plentiful protein was stimulated at low temperatures, further improving the system stability. Overall, the reasonably stable microbial community structure, enrichment of psychrotolerant microorganisms, and increased secretion of EPS could play important roles for stable sewage nitrogen removal at low temperatures.},
}
@article {pmid31783455,
year = {2020},
author = {Xu, J and Pang, H and He, J and Nan, J and Wang, M and Li, L},
title = {Start-up of aerobic granular biofilm at low temperature: Performance and microbial community dynamics.},
journal = {The Science of the total environment},
volume = {698},
number = {},
pages = {134311},
doi = {10.1016/j.scitotenv.2019.134311},
pmid = {31783455},
issn = {1879-1026},
abstract = {Low temperature is a great challenge for the biological treatment of wastewater. In this study, the rapid start-up of aerobic granular biofilm (AGF) reactor was realized by adding micro-sized polyurethane (PU) sponges as matrices at 10 °C. The results showed that the granulation process of AGF was different from that of traditional aerobic granular sludge and biofilms, which was formed by using the sludge intercepted in PU matrix instead of sponge skeletons as granulation carriers. During the 5-month operation period, stable pollutants removal performance was achieved within 70 days, besides, the corresponding ammonium, total nitrogen, and total phosphorus removal efficiencies were 98%, 70%, and 95%, respectively. The addition of PU matrices inhibited the growth of filamentous bacteria and provided support for high structural stability of AGF. With the operation of the reactor, the relative abundance of traditional denitrifying bacteria (genera Thauera and Acidovorax, etc.) decreased gradually, and the putative denitrifying phosphorus accumulating genus, Dechloromonas, occupied a dominant position in the system. This experiment showed that AGF system could be successfully started-up and operated with efficient pollutants removal performance under low temperature when using micro-sized PU sponges as matrices.},
}
@article {pmid31783343,
year = {2019},
author = {Dygico, LK and Gahan, CGM and Grogan, H and Burgess, CM},
title = {The ability of Listeria monocytogenes to form biofilm on surfaces relevant to the mushroom production environment.},
journal = {International journal of food microbiology},
volume = {317},
number = {},
pages = {108385},
doi = {10.1016/j.ijfoodmicro.2019.108385},
pmid = {31783343},
issn = {1879-3460},
abstract = {Due to its ubiquitous nature, Listeria monocytogenes is a threat to all fresh fruits and vegetables, including mushrooms, which are Ireland's largest horticultural crop. Although fresh cultivated mushrooms (Agaricus bisporus) have not been previously linked with listeriosis outbreaks, the pathogen still poses a threat to the industry, particularly due to its ability to form biofilms. This threat is highlighted by the multiple recalls of mushroom products caused by L. monocytogenes contamination and by previous studies demonstrating that L. monocytogenes is present in the mushroom production environment. In this study, the biofilm formation potential of L. monocytogenes strains isolated from the mushroom production environment was investigated on materials and at temperatures relevant to mushroom production. A preliminary assessment of biofilm formation of 73 mushroom industry isolates was undertaken using a crystal violet assay on polystyrene microtitre plates. The biofilm formation of a subset (n = 7) of these strains was then assessed on twelve different materials, including materials that are representative of the materials commonly found in the mushroom production environments, using the CDC biofilm reactor. Vertical scanning interferometry was used to determine the surface roughness of the chosen materials. All the strains tested using the CDC biofilm reactor were able to form biofilms on the different surfaces tested but material type was found to be a key determining factor on the levels of biofilm formed. Stainless steel, aluminium, rubber, polypropylene and polycarbonate were all able to support biofilm levels in the range of 4-4.9 log10 CFU/cm2, for seven different L. monocytogenes strains. Mushroom industry-specific materials, including growing nets and tarpaulins, were found to support biofilms levels between 4.7 and 6.7 log10 CFU/cm2. Concrete was found to be of concern as it supported 7.7 log10 CFU/cm2 of biofilm for the same strains; however, sealing the concrete resulted in an approximately 2-log reduction in biofilm levels. The surface roughness of the materials varied greatly between the materials (0.7-3.5 log10 Ra) and was found to have a positive correlation with biofilm formation (rs = 0.573) although marginally significant (P = 0.051). The results of this study indicate that L. monocytogenes can readily form biofilms on mushroom industry relevant surfaces, and additionally identifies surfaces of specific concern, where rigorous cleaning and disinfection is required.},
}
@article {pmid31780773,
year = {2019},
author = {Siddik, A and Satheesh, S},
title = {Characterization and assessment of barnacle larval settlement-inducing activity of extracellular polymeric substances isolated from marine biofilm bacteria.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {17849},
pmid = {31780773},
issn = {2045-2322},
support = {D-011-150-1440//King Abdulaziz University (King Abdulaziz University of Saudi Arabia)/ ; D-011-150-1440//King Abdulaziz University (King Abdulaziz University of Saudi Arabia)/ ; },
abstract = {Extracellular polymeric substances (EPSs) are the hydrated gelatinous matrix produced by microorganisms for attachment in a biofilm environment. In this study, the compositional variation between EPSs of three marine biofilm bacteria (Pseudoalteromonas shioyasakiensis, Vibrio harveyi and Planomicrobium sp.) were analysed by GC-MS, 1H NMR, FT-IR and XRD and SEM. The ecological significance of exopolymers was assessed in vivo using marine model organism barnacle larvae for their settlement-inducing activity. Chemical analysis revealed the presence of glycan fucosylated oligosaccharides, tetraose, trisaccharides, iso-B-Pentasaccharides, sialyllactose, oligomannose, galacto-N-biose, difucosyl-para-lacto-N-neohexaose, 3'-sialyl N-acetyllactosamine and isoglobotriaose-β-N(Acetyl)-Propargyl in all extracted EPSs. Bioassay results indicated that treatment of the barnacle larvae with EPSs from three bacterial strains enhanced settlement on substrates. In conclusion, this study highlighted the role of water-soluble EPSs in the invertebrate larval settlement on artificial materials.},
}
@article {pmid31780206,
year = {2019},
author = {Li, Q and Gu, P and Ji, X and Li, H and Zhang, J and Zheng, Z},
title = {Response of submerged macrophytes and periphyton biofilm to water flow in eutrophic environment: Plant structural, physicochemical and microbial properties.},
journal = {Ecotoxicology and environmental safety},
volume = {},
number = {},
pages = {109990},
doi = {10.1016/j.ecoenv.2019.109990},
pmid = {31780206},
issn = {1090-2414},
abstract = {The integrated effects of water flow on submerged macrophytes (Vallisneria natans) and leaf biofilms were comprehensively investigated in eutrophic microcosm. Changes in aquatic environmental factors were analyzed and water flow was found to elevate eutrophic water quality, especially in terms of TP removal. The removal efficiency of TP reached 78.95% in flowing water, which was more than 10-fold higher than in static water. Water flow altered the morphological and physiological characteristics of plants, decreasing the cell wall thickness and rate of photosynthesis, while promoting the accumulation of soluble sugar and protein in leaves. The starch content also increased with water flow, and significantly larger starch granules were observed in chloroplast. Furthermore, oxidative damage was evidenced by the consistently higher content of malondialdehyde in flowing water. Superoxide dismutase (SOD), peroxidase (POD) and Catalase (CAT) were induced in plants exposed to water flow, as an antioxidant stress response. The results of 16S rRNA high-throughput sequencing analysis showed that the structure of the biofilm microbial community changed in response to water flow. These results expand our understanding of the effects of water flow on submerged macrophytes and periphyton biofilms in eutrophic environments.},
}
@article {pmid31779615,
year = {2019},
author = {Batista, IR and Prates, ACL and Santos, BS and Araújo, JCC and Bonfim, YCO and Pimenta Rodrigues, MV and Morceli, G and Polettini, J and Cavalleri, AC and Winkelstroter, LK and Pereira, VC},
title = {Determination of antimicrobial susceptibility and biofilm production in Staphylococcus aureus isolated from white coats of health university students.},
journal = {Annals of clinical microbiology and antimicrobials},
volume = {18},
number = {1},
pages = {37},
pmid = {31779615},
issn = {1476-0711},
support = {2016/12252-2//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 2016/15809-8//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; },
abstract = {This study aimed at detecting Staphylococcus aureus from white coats of college students and characterizing antimicrobial susceptibility and biofilm production. Bacterial samples (n = 300) were obtained from white coats of 100 college students from August 2015 to March 2017 S. aureus was isolated and it´s resistance profile was assessed by antimicrobial disk-diffusion technique, screening for methicillin-resistant Staphylococcus aureus (MRSA), detection of mecA gene by PCR, and determination of staphylococcal cassette chromosome mec (SCCmec) by multiplex PCR. Congo red agar (CRA) and icaA and icaD genes by PCR were used for biofilm characterization. S. aureus was identified in 45.0% of samples. Resistance of S. aureus sample to antimicrobial was seen for penicillin (72.59%), erythromycin (51.85%), cefoxitin (20.74%), oxacillin (17.04%), clindamycin (14.81%) and levofloxacin (5.18%). MRSA was detected in 53.3% of the samples with SCCmec I (52.8%), SCCmec III (25%) and SCCmec IV (11.1%). Biofilm production was observed in 94.0% S. aureus samples. These data show that biosafety measures need to be enhanced in order to prevent dissemination of multiresistant and highly adhesive bacteria across other university settings, relatives, and close persons.},
}
@article {pmid31779259,
year = {2019},
author = {Yaita, K and Gotoh, K and Nakano, R and Iwahashi, J and Sakai, Y and Horita, R and Yano, H and Watanabe, H},
title = {Biofilm-Forming by Carbapenem Resistant Enterobacteriaceae May Contribute to the Blood Stream Infection.},
journal = {International journal of molecular sciences},
volume = {20},
number = {23},
pages = {},
doi = {10.3390/ijms20235954},
pmid = {31779259},
issn = {1422-0067},
abstract = {Bloodstream infection (BSI) due to carbapenem-resistant Enterobacteriaceae (CRE) has a high mortality rate and is a serious threat worldwide. Ten CRE strains (eight Enterobacter cloacae, one Klebsiella pneumoniae and one Citrobacter freundii) were isolated from the blood of nine patients, a percentage of whom had been treated with indwelling devices. The steps taken to establish cause included minimum inhibitory concentration (MIC) tests, a pulsed-field gel electrophoresis (PFGE), biofilm study, a multiplex PCR for resistant genes of carbapenemases and extended-spectrum beta-lactamases (ESBLs), and plasmid incompatibility typing. All strains showed a tendency toward resistance to multiple antibiotics, including carbapenems. Frequently isolated genes of ESBLs and carbapenemases include blaTEM-1 (four strains), blaSHV-12 (four strains) and blaIMP-1 (six strains). A molecular analysis by PFGE was used to divide the XbaI-digested genomic DNAs of 10 CRE strains into eight patterns, and the analysis showed that three E. cloacae strains detected from two patients were either identical or closely related. The biofilm production of all CRE strains was examined using a microtiter biofilm assay, and biofilm growth in continuous flow chambers was observed via the use of a confocal laser scanning microscope. Our study indicates that biofilm formation on indwelling devices may pose a risk of BSI due to CRE.},
}
@article {pmid31779134,
year = {2019},
author = {Varghese, J and Ramenzoni, LL and Shenoy, P and Nayak, UY and Nayak, N and Attin, T and Schmidlin, PR},
title = {In Vitro Evaluation of Substantivity, Staining Potential, and Biofilm Reduction of Guava Leaf Extract Mouth Rinse in Combination with its Anti-Inflammatory Effect on Human Gingival Epithelial Keratinocytes.},
journal = {Materials (Basel, Switzerland)},
volume = {12},
number = {23},
pages = {},
pmid = {31779134},
issn = {1996-1944},
abstract = {This study aimed to assess the biofilm reduction, staining potential, and cytotoxicity of guava extract mouth rinse compared to chlorhexidine (CHX). Substantivity, staining, and antibiofilm potential were investigated by spectrophotometry, colony-forming units, and luminosity color meter, respectively. The cell viability assay was conducted using a colorimetric assay to determine nontoxic levels of guava (0.15%) and CHX in human gingival epithelial keratinocytes (HGEK-16). Cells were treated with lipopolysaccharides (LPS, 1μg/mL) and guava to assess inflammatory gene expression levels of interleukin-β1, tumor necrosis factor-α, and Prostaglandin E2. A scratch wound healing assay investigated the effects of guava on cell migration. The teeth coated in guava mouth rinse displayed 19.4% higher substantivity compared to CHX (0.2%), and the anti-biofilm reduction was observed with both guava and CHX mouth rinses (P < 0.05). The overall discoloration changes were higher with CHX and distilled water compared to guava. Also, guava significantly enhanced HGEK-16 cell viability (P < 0.05), and IL-β1, TNFα and PGE2 expression presented a 0.6-fold decrease when exposed to guava and LPS (P < 0.05). The present study showed that guava mouth rinse fulfilled the requirement for an effective and useful oral care product with desirable substantivity and anti-biofilm action. In addition, guava reduced the inflammation response in HGEK-16 and may be a potential oral rinse for oral anti-inflammatory therapies.},
}
@article {pmid31778756,
year = {2019},
author = {Martínez, M and Polizzotto, A and Flores, N and Semorile, L and Maffía, PC},
title = {Antibacterial, anti-biofilm and in vivo activities of the antimicrobial peptides P5 and P6.2.},
journal = {Microbial pathogenesis},
volume = {139},
number = {},
pages = {103886},
doi = {10.1016/j.micpath.2019.103886},
pmid = {31778756},
issn = {1096-1208},
abstract = {Cationic antimicrobial peptides (AMPs) are short linear amino acid sequences, which display antimicrobial activity against a wide range of bacterial species. They are promising novel antimicrobials since they have shown bactericidal effects against multiresistant bacteria. Their amphiphilic structure with hydrophobic and cationic regions drives their interaction with anionic bacterial cytoplasmic membranes, which leads to their disruption. In this work two synthetic designed AMPs, P5 and P6.2, which have been previously analyzed in their ability to interact with bacterial or eukaryotic membranes, were evaluated in their anti-biofilm and in vivo antibacterial activity. In a first step, a time-kill kinetic assay against P. aeruginosa and S. aureus and a curve for hemolytic activity were performed in order to determine the killing rate and the possible undesirable toxic effect, respectively, for both peptides. The biofilm inhibitory activity was quantified at sub MIC concentrations of the peptides and the results showed that P5 displayed antibiofilm activity on both strains while P6.2 only on S. aureus. Scanning electron microscopy (SEM) of bacteria treated with peptides at their MIC revealed protruding blisters on Gam-negative P. aeruginosa strain, but almost no visible surface alteration on Gram-positive S. aureus. These micrographs highlighted different manifestations of the membrane-disrupting activity that these kinds of peptides possess. Finally, both peptides were analyzed in vivo, in the lungs of neutropenic mice previously instilled with P. aeruginosa. Mice lungs were surgically extracted and bacteria and pro-inflammatory cytokines (IL-β, IL-6 and TNF-α) were quantified by colony forming units and ELISA, respectively. Results showed that instillation of the peptides produced a significant decrease in the number of living bacteria in the lungs, concomitant with a decrease in pro-inflammatory cytokines. Overall, the results presented here suggest that these two new peptides could be good candidates for future drug development for anti-biofilm and anti-infective therapy.},
}
@article {pmid31778647,
year = {2019},
author = {Baron, G and Altomare, A and Regazzoni, L and Fumagalli, L and Artasensi, A and Borghi, E and Ottaviano, E and Del Bo, C and Riso, P and Allegrini, P and Petrangolini, G and Morazzoni, P and Riva, A and Arnoldi, L and Carini, M and Aldini, G},
title = {Profiling Vaccinium macrocarpon components and metabolites in human urine and the urine ex-vivo effect on Candida albicans adhesion and biofilm-formation.},
journal = {Biochemical pharmacology},
volume = {},
number = {},
pages = {113726},
doi = {10.1016/j.bcp.2019.113726},
pmid = {31778647},
issn = {1873-2968},
abstract = {The aim of this work was to profile, by using an HPLC-MS/MS method, cranberry compounds and metabolites found in human urine after ingestion of a highly standardized cranberry extract (Anthocran®). Two different strategies were adopted for the data analysis: a targeted and an untargeted approach. These strategies allowed the identification of 42 analytes including cranberry components, known metabolites and metabolites hitherto unreported in the literature, including six valerolactones/valeric acid derivatives whose presence in urine after cranberry consumption has never been described before. Absolute concentrations of 26 over 42 metabolites were obtained by using pure available standards. Urine collected at different time points after the last dosage of Anthocran® were tested on the reference strain C. albicans SC5314, a biofilm-forming strain. Fractions collected after 12 h were found to significantly reduce the adhesion and biofilm formation compared to the control (p < 0.05). A similar effect was then obtained by using Anthocran™ Phytosome™, the lecithin formulation containing 1/3 of standardized cranberry extract and formulated to enhance the absorption of the cranberry components. The urinary profile of cranberry components and metabolites in the urine fractions collected at 1 h, 6 h and 12 h after the last capsule intake were then reproduced by using the pure standards at the concentration ranges found in the urine fraction, and tested on C. albicans. Only the mixture mimicking the urinary fraction collected at 12 h and containing as main components, quercetin and 5-(3',4'-dihydroxyphenyl)-γ-valerolactone was found effective thus confirming the ex-vivo results.},
}
@article {pmid31778202,
year = {2019},
author = {Salisbury, AM and Chen, R and Mullin, M and Foulkes, L and Percival, SL},
title = {The Effects of a Concentrated Surfactant Gel on Biofilm EPS.},
journal = {Surgical technology international},
volume = {36},
number = {},
pages = {},
pmid = {31778202},
issn = {1090-3941},
abstract = {INTRODUCTION: The aim of this study was to evaluate if a poloxamer-based concentrated surfactant gel (CSG), containing antibacterial preservative agents, had the ability to reduce the levels of biofilm extracellular polymeric substances (EPS), specifically proteins and extracellular DNA (eDNA), as these are found to be the most immunogenic, within an in vitro biofilm.<br><br>MATERIALS AND METHODS: A 24-hour biofilm of P. aeruginosa ATCC 15442 was grown in a 12-well plate and treated for 24 hours with a CSG coated onto Multisorb® (BSN Medical Limited, Hull, United Kingdom). EPS were extracted from each sample using 1M sodium chloride. Protein and DNA in EPS extractions was determined quantitatively using the Pierce™ Coomassie (Bradford) protein assay kit and a microplate SYTO 9™ (ThermoFisher Scientific, Paisley, United Kingdom) fluorescent assay, respectively. Protein and DNA was also determined qualitatively using confocal laser scanning microscopy (CLSM).<br><br>RESULTS: Following 24-hour growth of P. aeruginosa ATCC 15442 biofilm, 7.38mg/mL protein was isolated from the extracted EPS in the untreated control. In comparison, the protein concentration found in the extracted EPS from biofilms treated with a CSG was 6.39mg/mL, showing a 13.4% reduction. Following 24-hour growth of P. aeruginosa ATCC 15442 biofilm, 11.71mg/mL eDNA was isolated from the extracted EPS in the untreated control. In comparison, the eDNA concentration found in the extracted EPS from biofilms treated with a CSG was 0.65mg/mL, showing a 94.5% reduction. Following statistical analysis of the data, the decrease in protein isolated following CSG treatment was within error; however, the decrease in eDNA isolated was statistically significant, showing the ability of the CSG to break up biofilm EPS in vitro. Using confocal laser microscopy and staining techniques, a large quantity of protein and eDNA could be observed in samples from the untreated control. In comparison, a reduction in EPS protein and eDNA was observed in samples that had been treated with a CSG.<br><br>CONCLUSION: The data presented here potentially shows the ability of a CSG to reduce components of the P. aeruginosa biofilm EPS. The reduction in eDNA following CSG treatment may contribute to the dispersal of the biofilm, potentially increasing the susceptibility of it to antimicrobials, and should be explored further.},
}
@article {pmid31778072,
year = {2019},
author = {Maheshwari, M and Abul Qais, F and Althubiani, AS and Abulreesh, HH and Ahmad, I},
title = {Bioactive extracts of Carum copticum and thymol inhibit biofilm development by multidrug-resistant extended spectrum β-lactamase producing enteric bacteria.},
journal = {Biofouling},
volume = {35},
number = {9},
pages = {1026-1039},
doi = {10.1080/08927014.2019.1688305},
pmid = {31778072},
issn = {1029-2454},
abstract = {The emergence and spread of multidrug-resistant (MDR) pathogenic bacteria is a clinical problem that requires novel anti-infective agents. Targeting pathogenic biofilms is considered a promising strategy to control bacterial infections. In this study, bioactive extracts of Carum copticum were investigated for their anti-biofilm efficacy against extended spectrum β-lactamase (ESβL) producing MDR enteric bacteria. Thymol was also tested for its anti-biofilm properties, as gas chromatography-mass spectrometry revealed a high content (65.8%) of this phytochemical in the C. copticum methanolic extract. Biofilm inhibition was assessed in microtitre plates and further validated by light, electron and confocal laser microscopy. Sub-inhibitory concentrations of bioactive extracts of C. copticum and thymol significantly prevented biofilm development, ranging from 78.6 to 83.9% reductions. Microscopic analysis revealed that biofilms made by ESβL producing MDR enteric bacteria had a weakened structure, scattered microcolonies, and reduced cell density and thickness after exposure to the bioactive extracts and thymol.},
}
@article {pmid31778071,
year = {2019},
author = {Afonso, TB and Simões, LC and Lima, N},
title = {In vitro assessment of inter-kingdom biofilm formation by bacteria and filamentous fungi isolated from a drinking water distribution system.},
journal = {Biofouling},
volume = {},
number = {},
pages = {1-14},
doi = {10.1080/08927014.2019.1688793},
pmid = {31778071},
issn = {1029-2454},
abstract = {The main focus so far in the study of biofilm formation in drinking water has been bacteria. Studies on biofilm formation involving filamentous fungi are, therefore, scarce. This study aimed to assess and characterize the ability of these microorganisms to interact with bacteria whilst forming inter-kingdom biofilms. Biofilms were analysed in terms of total biomass, metabolic activity, bacterial colony forming units and morphology by epifluorescence microscopy. The quantitative methods revealed that biofilm mass increased over time for both single and inter-kingdom biofilms, while specific metabolic activity decreased, in general, along the time points evaluated. Microscopic data visually confirmed the biofilm mass increase over time. This study shows that fungal stage development is important in the first 24 h of biofilm formation. Inter-kingdom biofilm formation is microorganism dependent and inter-kingdom biofilms may provide an advantage to the opportunistic bacterium Acinetobacter calcoaceticus to replicate and proliferate when compared with Methylobacterium oryzae.},
}
@article {pmid31776432,
year = {2019},
author = {Sindi, A and Chawn, MVB and Hernandez, ME and Green, K and Islam, MK and Locher, C and Hammer, K},
title = {Anti-biofilm effects and characterisation of the hydrogen peroxide activity of a range of Western Australian honeys compared to Manuka and multifloral honeys.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {17666},
pmid = {31776432},
issn = {2045-2322},
support = {PRJ-010313//Agrifutures Australia/ ; PRJ-010313//Agrifutures Australia/ ; },
abstract = {The antibacterial activity of honeys derived from the endemic flora of the southwest corner of Western Australia, including the trees Jarrah (Eucalyptus marginata) and Marri (Corymbia calophylla), remains largely unexplored. Investigation of these honeys showed minimum inhibitory concentrations (MICs) of 6.7-28.0% (w/v) against Gram positive and negative bacteria. Honey solutions showed enhanced antibacterial activity after hydrogen peroxide was allowed to accumulate prior to testing, with a mean MIC after accumulation of 14.3% compared to 17.4% before accumulation. Antibacterial activity was reduced after treatment with catalase enzyme, with a mean MIC of 29.4% with catalase compared to 15.2% without catalase. Tests investigating the role of the Gram negative outer membrane in honey susceptibility revealed increases in activity after destabilisation of the outer membrane. Honeys reduced both the formation of biofilm and the production of bacterial pigments, which are both regulated by quorum sensing. However, these reductions were closely correlated with global growth inhibition. Honey applied to existing biofilms resulted in decreased metabolic activity and minor decreases in viability. These results enhance our understanding of the mechanisms of antibacterial action of Jarrah and Marri honeys, and provide further support for the use of honey in the treatment of infected wounds.},
}
@article {pmid31775200,
year = {2019},
author = {Wu, Y and Li, J and Qiao, M and Meng, D and Meng, Q and Qiao, J and Zhang, X and Wang, L and Cai, K and Zhang, J and Zhang, Z and Yu, W and Cai, X},
title = {Characteristic profiles of biofilm, enterotoxins and virulence of Staphylococcus aureus isolates from dairy cows in Xinjiang Province, China.},
journal = {Journal of veterinary science},
volume = {20},
number = {6},
pages = {e74},
doi = {10.4142/jvs.2019.20.e74},
pmid = {31775200},
issn = {1976-555X},
abstract = {As an important zoonotic pathogen, Staphylococcus aureus has led to serious mastitis and endometritis in infected dairy cows. In this study, a total of 164 strains of S. aureus were isolated from dairy cows in Xinjiang Province, China, and subjected to assays to determine drug susceptibility and biofilm (BF) formation ability. Enterotoxin-related genes were detected, and the transcription levels of genes related to BF formation were determined by using reverse transcription-quantitative polymerase chain reaction. Moreover, the pathogenicity of isolates with different BF formation abilities was determined by measuring their hemolysis activity, half lethal dose (LD50) and organ bacterial load. The results showed that 86.0% of S. aureus isolates could form BF. Among them, 42.1% of the strains had weak BF formation ability, and most strains with a strong BF formation ability were ica gene carriers. The S. aureus isolates displayed multidrug resistance and their drug resistance was positively correlated with their BF formation ability. Moreover, 96.3% of the S. aureus isolates carried enterotoxin genes. Among them, the detection rates of the novel enterotoxin genes were higher than those of conventional enterotoxin genes. Furthermore, isolates with a strong BF formation ability had higher LD50 but lower hemolysis ability and organ bacterial load than those of the isolates with weak or no BF ability. However, isolates without BF ability produced more severe pathological changes than those of isolates with strong BF formation ability. These findings suggest that higher BF ability and presence of novel enterotoxin genes are important characteristics of S. aureus isolates from dairy cows in Xinjiang Province, China, and such isolates may pose potential threats to food safety.},
}
@article {pmid31774855,
year = {2019},
author = {Senpuku, H and Tuna, EB and Nagasawa, R and Nakao, R and Ohnishi, M},
title = {The inhibitory effects of polypyrrole on the biofilm formation of Streptococcus mutans.},
journal = {PloS one},
volume = {14},
number = {11},
pages = {e0225584},
pmid = {31774855},
issn = {1932-6203},
abstract = {Streptococcus mutans primary thrives on the biofilm formation on the tooth surface in sticky biofilms and under certain conditions can lead to carious lesions on the tooth surface. To search for a new preventive material for oral biofilm-associated diseases, including dental caries, we investigated the effects of polypyrrole, which contains an electrochemical polymer and causes protonation and incorporation of anion under low pH condition, on the biofilm formation of S. mutans and other streptococci. In this study, polypyrrole was applied in biofilm formation assays with the S. mutans strains UA159 and its gtfB and gtfC double mutant (gtfBC mutant), S. sanguinis, S. mitis and S. gordonii on human saliva and bovine serum albumin-coated 96-well microtiter plates in tryptic soy broth supplemented with 0.25% sucrose. The effects of polypyrrole on biofilm formation were quantitatively and qualitatively observed. High concentrations of polypyrrole significantly inhibited the biofilm formation of S. mutans UA159 and S. sanguinis. As an inhibition mechanism, polypyrrole attached to the surface of bacterial cells, increased chains and aggregates, and incorporated proteins involving GTF-I and GTF-SI produced by S. mutans. In contrast, the biofilm formation of gtfBC mutant, S. sanguinis, S. mitis and S. gordonii was temporarily induced by the addition of low polypyrrole concentrations on human saliva-coated plate but not on the uncoated and bovine serum albumin-coated plates. Moreover, biofilm formation depended on live cells and, likewise, specific interaction between cells and binding components in saliva. However, these biofilms were easily removed by increased frequency of water washing. In this regard, the physical and electrochemical properties in polypyrrole worked effectively in the removal of streptococci biofilms. Polypyrrole may have the potential to alter the development of biofilms associated with dental diseases.},
}
@article {pmid31773197,
year = {2019},
author = {Chakraborty, P and Dastidar, DG and Paul, P and Dutta, S and Basu, D and Sharma, SR and Basu, S and Sarker, RK and Sen, A and Sarkar, A and Tribedi, P},
title = {Inhibition of biofilm formation of Pseudomonas aeruginosa by caffeine: a potential approach for sustainable management of biofilm.},
journal = {Archives of microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00203-019-01775-0},
pmid = {31773197},
issn = {1432-072X},
abstract = {Pseudomonas aeruginosa is a potent biofilm forming organism causing several diseases on host involving biofilm. Several natural and synthetic molecules have been explored towards inhibiting the biofilm formation of Pseudomonas aeruginosa. In the current report, the role of a natural molecule namely caffeine was examined against the biofilm forming ability of P. aeruginosa. We have observed that caffeine shows substantial antimicrobial activity against P. aeruginosa wherein the minimum inhibitory concentration (MIC) of caffeine was found to be 200 μg/mL. The antibiofilm activity of caffeine was determined by performing a series of experiments using its sub-MIC concentrations (40 and 80 μg/mL). The results revealed that caffeine can significantly inhibit the biofilm development of P. aeruginosa. Caffeine has been found to interfere with the quorum sensing of P. aeruginosa by targeting the swarming motility. Molecular docking analysis further indicated that caffeine can interact with the quorum sensing proteins namely LasR and LasI. Thus, the result indicated that caffeine could inhibit the formation of biofilm by interfering with the quorum sensing of the organism. Apart from biofilm inhibition, caffeine has also been found to reduce the secretion of virulence factors from Pseudomonas aeruginosa. Taken together, the results revealed that in addition to biofilm inhibition, caffeine can also decrease the spreading of virulence factors from Pseudomonas aeruginosa.},
}
@article {pmid31772059,
year = {2019},
author = {Ma, D and Mandell, JB and Donegan, NP and Cheung, AL and Ma, W and Rothenberger, S and Shanks, RMQ and Richardson, AR and Urish, KL},
title = {The Toxin-Antitoxin MazEF Drives Staphylococcus aureus Biofilm Formation, Antibiotic Tolerance, and Chronic Infection.},
journal = {mBio},
volume = {10},
number = {6},
pages = {},
pmid = {31772059},
issn = {2150-7511},
support = {P30 EY008098/EY/NEI NIH HHS/United States ; },
abstract = {Staphylococcus aureus is the major organism responsible for surgical implant infections. Antimicrobial treatment of these infections often fails, leading to expensive surgical intervention and increased risk of mortality to the patient. The challenge in treating these infections is associated with the high tolerance of S. aureus biofilm to antibiotics. MazEF, a toxin-antitoxin system, is thought to be an important regulator of this phenotype, but its physiological function in S. aureus is controversial. Here, we examined the role of MazEF in developing chronic infections by comparing growth and antibiotic tolerance phenotypes in three S. aureus strains to their corresponding strains with disruption of mazF expression. Strains lacking mazF production showed increased biofilm growth and decreased biofilm antibiotic tolerance. Deletion of icaADBC in the mazF::Tn background suppressed the growth phenotype observed with mazF-disrupted strains, suggesting the phenotype was ica dependent. We confirmed these phenotypes in our murine animal model. Loss of mazF resulted in increased bacterial burden and decreased survival rate of mice compared to its wild-type strain demonstrating that loss of the mazF gene caused an increase in S. aureus virulence. Although lack of mazF gene expression increased S. aureus virulence, it was more susceptible to antibiotics in vivo Combined, the ability of mazF to inhibit biofilm formation and promote biofilm antibiotic tolerance plays a critical role in transitioning from an acute to chronic infection that is difficult to eradicate with antibiotics alone.IMPORTANCE Surgical infections are one of the most common types of infections encountered in a hospital. Staphylococcus aureus is the most common pathogen associated with this infection. These infections are resilient and difficult to eradicate, as the bacteria form biofilm, a community of bacteria held together by an extracellular matrix. Compared to bacteria that are planktonic, bacteria in a biofilm are more resistant to antibiotics. The mechanism behind how bacteria develop this resistance and establish a chronic infection is unknown. We demonstrate that mazEF, a toxin-antitoxin gene, inhibits biofilm formation and promotes biofilm antibiotic tolerance which allows S. aureus to transition from an acute to chronic infection that cannot be eradicated with antibiotics but is less virulent. This gene not only makes the bacteria more tolerant to antibiotics but makes the bacteria more tolerant to the host.},
}
@article {pmid31771981,
year = {2019},
author = {Anderson, EM and Sychantha, D and Brewer, D and Clarke, AJ and Geddes-McAlister, J and Khursigara, CM},
title = {Peptidoglycomics reveals compositional changes in peptidoglycan between biofilm- and planktonic-derived Pseudomonas aeruginosa.},
journal = {The Journal of biological chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1074/jbc.RA119.010505},
pmid = {31771981},
issn = {1083-351X},
abstract = {Peptidoglycan (PG) is a critical component of the bacterial cell wall and is composed of a repeating β-1,4-linked disaccharide of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) appended with a highly conserved stem peptide. In Gram-negative bacteria, PG is assembled in the cytoplasm and exported into the periplasm where it undergoes considerable maturation, modification, or degradation depending on the growth phase or presence of environmental stressors. These modifications serve important functions in diverse processes, including PG turnover, cell elongation/division, and antibiotic resistance. Conventional methods for analyzing PG composition are complex and time consuming. We present here a streamlined MS-based method that combines differential analysis with statistical 1D annotation approaches to quantitatively compare PGs produced in planktonic- and biofilm-cultured Pseudomonas aeruginosa We identified a core assembly of PG that is present in high abundance and that does not significantly differ between the two growth states. We also identified an adaptive PG assembly that is present in smaller amounts and fluctuates considerably between growth states in response to physiological changes. Biofilm-derived adaptive PG exhibited significant changes compared with planktonic-derived PG, including amino acid substitutions of the stem peptide and modifications that indicate changes in the activity of amidases, deacetylases, and lytic transglycosylases. The results of this work also provide first evidence of de-N-acetylated muropeptides from P. aeruginosa The method developed here offers a robust and reproducible workflow for accurately determining PG composition in samples that can be used to assess global PG fluctuations in response to changing growth conditions or external stimuli.},
}
@article {pmid31771575,
year = {2019},
author = {Phophi, L and Petzer, IM and Qekwana, DN},
title = {Antimicrobial resistance patterns and biofilm formation of coagulase-negative Staphylococcus species isolated from subclinical mastitis cow milk samples submitted to the Onderstepoort Milk Laboratory.},
journal = {BMC veterinary research},
volume = {15},
number = {1},
pages = {420},
pmid = {31771575},
issn = {1746-6148},
abstract = {BACKGROUND: Increased prevalence of antimicrobial resistance, treatment failure, and financial losses have been reported in dairy cows with coagulase-negative Staphylococcus (CoNS) clinical mastitis, however, studies on CoNS infections are limited in South Africa. Therefore, the objectives of this study were to investigate the antimicrobial resistance patterns and biofilm formation in CoNS isolated from cow milk samples submitted to the Onderstepoort Milk Laboratory.<br><br>RESULTS: A total of 142 confirmed CoNS isolates were used for this study. Biofilm formation was identified in 18% of CoNS tested. Staphylococcus chromogenes (11%) had the highest proportion of biofilm formation followed by S. haemolyticus (4.0%), S. epidermidis, S. hominis, S. xylosus, and S. simulans with 1% respectively. Ninety percent (90%) of CoNS were resistant to at least one antimicrobial (AMR) and 51% were multidrug-resistant (MDR). Resistance among CoNS was the highest to ampicillin (90%) and penicillin (89%), few isolates resistant to cefoxitin and vancomycin, 9% respectively. Similarly, MDR-S. haemolyticus (44%), MDR-S. epidermidis (65%), and MDR-S. chromogenes (52%) were mainly resistant to penicillins. The most common resistance patterns observed were resistance to penicillin-ampicillin (16%) and penicillin-ampicillin-erythromycin (10%). Only 42% of biofilm positive CoNS were MDR.<br><br>CONCLUSION: The majority of CoNS in this study were resistance to penicillins. In addition, most isolates were β-lactam resistant and MDR. Biofilm formation among the CoNS in this study was uncommon and there was no significant difference in the proportion of MDR-CoNS based on the ability to form a biofilm.},
}
@article {pmid31771160,
year = {2019},
author = {Olszak, T and Danis-Wlodarczyk, K and Arabski, M and Gula, G and Maciejewska, B and Wasik, S and Lood, C and Higgins, G and Harvey, BJ and Lavigne, R and Drulis-Kawa, Z},
title = {Pseudomonas aeruginosa PA5oct Jumbo Phage Impacts Planktonic and Biofilm Population and Reduces Its Host Virulence.},
journal = {Viruses},
volume = {11},
number = {12},
pages = {},
doi = {10.3390/v11121089},
pmid = {31771160},
issn = {1999-4915},
support = {2012/04/M/NZ6/00335//Narodowe Centrum Nauki/ ; 2015/18/M/NZ6/00413//Narodowe Centrum Nauki/ ; 1S64718N//Fonds Wetenschappelijk Onderzoek Vlaanderen/ ; GOA &quot;Phage Biosystems&quot;//KU Leuven/ ; },
abstract = {The emergence of phage-resistant mutants is a key aspect of lytic phages-bacteria interaction and the main driver for the co-evolution between both organisms. Here, we analyze the impact of PA5oct jumbo phage treatment on planktonic/cell line associated and sessile P. aeruginosa population. Besides its broad-spectrum activity and efficient bacteria reduction in both airway surface liquid (ASL) model, and biofilm matrix degradation, PA5oct appears to persist in most of phage-resistant clones. Indeed, a high percentage of resistance (20/30 clones) to PA5oct is accompanied by the presence of phage DNA within bacterial culture. Moreover, the maintenance of this phage in the bacterial population correlates with reduced P. aeruginosa virulence, coupled with a sensitization to innate immune mechanisms, and a significantly reduced growth rate. We observed rather unusual consequences of PA5oct infection causing an increased inflammatory response of monocytes to P. aeruginosa. This phenomenon, combined with the loss or modification of the phage receptor, makes most of the phage-resistant clones significantly less pathogenic in in vivo model. These findings provide new insights into the general knowledge of giant phages biology and the impact of their application in phage therapy.},
}
@article {pmid31769530,
year = {2019},
author = {Ganesh, PS and Vishnupriya, S and Vadivelu, J and Mariappan, V and Vellasamy, KM and Shankar, EM},
title = {Intracellular Survival and Innate Immune Evasion of Burkholderia cepacia: Improved Understanding of Quorum Sensing-Controlled Virulence Factors, Biofilm and Inhibitors.},
journal = {Microbiology and immunology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1348-0421.12762},
pmid = {31769530},
issn = {1348-0421},
abstract = {B. cepacia complex (Bcc) are opportunistic pathogens implicated with nosocomial infections, and high rates of morbidity and mortality, especially in individuals with cystic fibrosis (CF). B.cepacia are naturally resistant to different classes of antibiotics, and can subvert the host innate immune responses by producing quorum sensing (QS) controlled virulence factors and biofilms. It still remains a conundrum as to how exactly the bacterium survives the intracellular environment within the host cells of CF patients and the immunocompromised although the bacterium can invade human lung epithelial cells, neutrophils and murine macrophages. The mechanisms associated with intracellular survival in the airway epithelial cells and the role of QS and virulence factors in B. cepacia infections in CF largely remain unclear. The current review focuses to understand the role of QS-controlled virulence factors and biofilms, and provides additional impetus to understanding the potentials of QS-inhibitory strategies against B. cepacia. This article is protected by copyright. All rights reserved.},
}
@article {pmid31769202,
year = {2019},
author = {Chen, Q and Xie, S and Lou, X and Cheng, S and Liu, X and Zheng, W and Zheng, Z and Wang, H},
title = {Biofilm formation and prevalence of adhesion genes among Staphylococcus aureus isolates from different food sources.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e946},
doi = {10.1002/mbo3.946},
pmid = {31769202},
issn = {2045-8827},
support = {2017A66//The Health and Technology Program of Hangzhou/ ; 81700768//The National Natural Science Foundation of China/ ; },
abstract = {To assess biofilm formation ability and identify differences in the prevalence of genes involved in biofilm formation among Staphylococcus aureus strains isolated from different food samples, the ability of biofilm formation among 97 S. aureus strains was evaluated using a colorimetric microtiter plate assay. Thirteen genes encoding microbial surface components recognizing adhesive matrix molecules, and the intracellular adhesion genes were detected by PCR using specific primers. Approximately 72% of the isolates produced biofilms. Among these isolates, 54.64% were weak biofilm producers, while 14.43% and 3.09% produced moderate and strong biofilms, respectively. The icaADBC, clfA/B, cidA, and fib genes were detected in all the S. aureus strains, whereas the bap gene was not present in any of the strains. The occurrence of other adhesin genes varied greatly between biofilm-producing and nonbiofilm-producing strains. However, a significant difference was observed between these two groups with respect to the fnbpB, cna, ebps, and sdrC genes. No obvious evidence was found to support the link between PFGE strain typing and the capacity for biofilm formation. Considerable variation in biofilm formation ability was observed among S. aureus strains isolated from food samples. The prevalence of adhesin-encoding genes also varied greatly within strains. This study highlights the importance of biofilm formation and the adhesins of S. aureus strains in food samples.},
}
@article {pmid31768723,
year = {2019},
author = {Fekrirad, Z and Kashef, N and Arefian, E},
title = {Photodynamic inactivation diminishes quorum sensing-mediated virulence factor production and biofilm formation of Serratia marcescens.},
journal = {World journal of microbiology &amp; biotechnology},
volume = {35},
number = {12},
pages = {191},
pmid = {31768723},
issn = {1573-0972},
abstract = {Serratia marcescens is an opportunistic human pathogen causing nosocomial infections and displays expanded resistance towards the conventional antibiotics. In S. marcescens, quorum sensing (QS) mechanism coordinates the population-dependent behaviors and regulates the virulence factors production. Photodynamic inactivation (PDI) is a promising alternative for the treatment of infections caused by drug resistant bacteria. Although PDI should be applied at lethal doses, it is possible that during PDI treatment, pathogens encounter sub-lethal doses of PDI (sPDI). sPDI cannot kill microorganisms, but it can considerably influence the microbial virulence. So, in this study, the effect of methylene blue (MB)-mediated PDI on QS-mediated virulence factor production and biofilm formation of S. marcescens at lethal and sub-lethal doses was evaluated. The biofilm formation and virulence factor production of S. marcescens ATCC 13,880 and S. marcescens Sm2 were assessed before and after PDI treatment. Besides, the effect of lethal and sub-lethal PDI on expression of bsmA and bsmB (Biofilm maturation), fimA and fimC (Major fimbrial protein), flhD (Regulator of flagellar mediated swarming and swimming motility) and swrR (AHL-dependent regulator) genes were evaluated by quantitative real time polymerase chain reaction. Lethal and sub-lethal PDI resulted in a significant decrease in biofilm formation, swimming/swarming motility, and pigment and hemolysin production ability of S. marcescens strains. bsmA, bsmB, flhD and swrR genes were down-regulated after PDI treatments. In conclusion, QS-mediated virulence factor production and biofilm formation ability of the two studied S. marcescens strains decreased after both lethal and sub-lethal PDI.},
}
@article {pmid31768611,
year = {2019},
author = {Kischkel, B and Souza, GK and Chiavelli, LUR and Pomini, AM and Svidzinski, TIE and Negri, M},
title = {The ability of farnesol to prevent adhesion and disrupt Fusarium keratoplasticum biofilm.},
journal = {Applied microbiology and biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00253-019-10233-2},
pmid = {31768611},
issn = {1432-0614},
support = {421620/2018-8//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; },
abstract = {A biofilm is represented by a community of microorganisms capable of adhering to a surface and producing substances that envelop the cells, forming an extracellular matrix. The extracellular matrix is responsible for protecting microorganisms against environmental stress, hosts the immune system and confers resistance to antimicrobials. Fusarium keratoplasticum is a common species of FSSC (Fusarium solani species complex) associated with human infections, being the most prevalent species related to biofilm formation in hospital water systems and internal pipelines. With this in mind, this study aimed to characterise the biofilm formed by the fungus F. keratoplasticum and to evaluate the effects of farnesol, a fungal quorum sensing (QS) molecule, on the preformed biofilm and also during its formation at different times (adhesion and 24, 48 and 72 h). F. keratoplasticum is able to adhere to an abiotic surface and form a dense biofilm in 72 h, with increased total biomass and matrix modulation with the presence of extracellular DNA, RNA, polysaccharides and proteins. Farnesol exhibited important anti-biofilm activity, causing the destruction of hyphae and the extracellular matrix in preformed biofilm and preventing the adhesion of conidia, filamentation and the formation of biofilm. Few studies have characterised the formation of biofilm by filamentous fungi. Our findings suggest that farnesol acts efficiently on F. keratoplasticum biofilm since this molecule is capable of breaking the extracellular matrix, thereby disarranging the biofilm.},
}
@article {pmid31767527,
year = {2019},
author = {Vijay, AK and Zhu, H and Willcox, M and Ketelson, H and Stapleton, F},
title = {Bacterial biofilm in silver-impregnated contact lens cases.},
journal = {Contact lens &amp; anterior eye : the journal of the British Contact Lens Association},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.clae.2019.11.004},
pmid = {31767527},
issn = {1476-5411},
abstract = {PURPOSE: This study investigated the efficacy of pre-conditioning lens cases on bacterial biofilm formation and removal.<br><br>METHODS: Silver impregnated (MicroBlock / ProGuard™ &amp; i-Clean) and control storage cases were pre-conditioned for 24 h with their respective multipurpose solutions (MPDSs). Cases were then inoculated with 2 ml of 106 CFU/mL of ocular isolates of either P. aeruginosa or S. aureus and incubated for 48 h. Cases were subsequently disinfected (4-6 hours) as per the manufacturer's recommended disinfecting time (MRDT) followed by the recommended case hygiene procedures - recapping wet (MicroBlock / ProGuard™ cases only) or rinse and air-dry or rinse, tissue-wipe and air dry (mechanical disruption). Surviving bacteria were enumerated using standard techniques.<br><br>RESULTS: Pre-conditioning the MicroBlock / ProGuard™ cases with MPDS significantly reduced biofilm formation (-1.1 log10 CFU, p < 0.01 for P. aeruginosa &amp; -1.3 log10, p < 0.001, CFU for S. aureus) compared to the i-Clean lens cases. Maintaining the MicroBlock / ProGuard™ lens cases wet after the MRDT resulted in partial removal of bacterial biofilms (-2.9 log10 CFU, p < 0.001 for P. aeruginosa and -2.6 log10 CFU, p < 0.001 for S. aureus). Air-drying of all three types of lens storage cases after MRDT significantly reduced the bacterial biofilm (-5.4 log10 CFU, p < 0.001 for P. aeruginosa and -3.5 log10 CFU, p < 0.001 for S. aureus). Mechanical disruption produced the greatest reduction in the levels of bacterial biofilm in all 3 types of lens cases tested (-6.8 log10 CFU, p < 0.001 for P. aeruginosa and -4.5 log10 CFU, p < 0.001 for S. aureus). Synergi MPDS was significantly better than AQuify MPDS in removing bacterial biofilm from all 3 lens case types for case hygiene treatments with an air-drying step.<br><br>CONCLUSION: Pre-conditioning of silver-impregnated ProGuard™ lens cases inhibited initial bacterial biofilm formation. Synergi MPDS was more effective than AQuify MPDS in removing bacterial biofilm in silver impregnated cases and tissue-wiping significantly improved biofilm removal.},
}
@article {pmid31767091,
year = {2019},
author = {Vasileiou, NGC and Cripps, PJ and Ioannidi, KS and Katsafadou, AI and Chatzopoulos, DC and Barbagianni, MS and Tsioli, V and Dermisiadou, E and Karavanis, E and Papadopoulos, N and Lianou, DT and Mavrogianni, VS and Petinaki, E and Fthenakis, GC},
title = {Experimental study for evaluation of the efficacy of a biofilm-embedded bacteria-based vaccine against Staphylococcus chromogenes-associated mastitis in sheep.},
journal = {Veterinary microbiology},
volume = {239},
number = {},
pages = {108480},
doi = {10.1016/j.vetmic.2019.108480},
pmid = {31767091},
issn = {1873-2542},
abstract = {Although coagulase-negative staphylococci are the primary aetiological agents of subclinical mastitis in ewes, there is little information regarding vaccination against that infection. The objective of this study was to evaluate the efficacy of a vaccine against staphylococcal mastitis in ewes under experimental conditions. The antigen in the vaccine is based on a bacterin of Staphylococcus aureus strain, expressing the exopolysaccharide poly-N-acetylglucosamine (PNAG), which is involved in biofilm formation by these bacteria. Ewes in groups A (n = 17) or B (n = 6) were given an initial vaccination 5 weeks before expected lambing, followed by a repeat administration 21 days later. Ewes in groups C (n = 8) or D (n = 6) were unvaccinated controls. Ewes in group A (n = 17) or C (n = 8) were challenged with a biofilm-forming S. chromogenes; animals in subgroups A1 or C1 were challenged on the 10th and those in A2 or C2 on the 50th day after lambing. Ewes in groups B or D were uninoculated controls. Clinical examinations of ewes, ultrasonographic examinations of udder, milk yield measurements, blood sampling for detection of anti-PNAG specific antibodies and milk sample collection for bacteriological and cytological examinations were performed up to 52nd day post-challenge. Finally, biopsies were performed for mammary tissue collection for histopathological examination. Among group A ewes, 29% developed systemic signs and 59% signs in the inoculated gland; the respective figures for group C were 50% and 100% (P = 0.040 for mammary signs). The median total clinical score was 2.0 for A and 5.5 for C ewes (P = 0.025). For A, but not for C, clinical scores decreased progressively during the study (P = 0.018 and P = 0.47, respectively). The duration of mastitis was shorter in A (4 days) than in C (17.5 days) ewes (P = 0.022). Bacterial counts were lower in milk samples from A than from C ewes, for samples collected from the inoculated and the uninoculated (P < 0.01) mammary glands of these ewes. Somatic cell counts in samples from inoculated and uninoculated mammary glands of A ewes were higher than in samples of C ewes (P < 0.02). There were differences for gray-scale evaluations during ultrasonographic examination and for milk yield measurements between groups (P < 0.01). Median bacterial counts in tissue samples from A ewes (0 cfu g-1) were lower than in ones from C (6.5 cfu g-1) ewes (P = 0.041). The median score for histopathological findings in tissue samples from inoculated glands of A was lower than that for C ewes: 1 versus 2 (P = 0.014). It is concluded that mastitis was less severe in vaccinated animals, as indicated by a wide array of measures.},
}
@article {pmid31766551,
year = {2019},
author = {Fleming, G and Aveyard, J and Fothergill, JL and McBride, F and Raval, R and D'Sa, RA},
title = {Effect of Polymer Demixed Nanotopographies on Bacterial Adhesion and Biofilm Formation.},
journal = {Polymers},
volume = {11},
number = {12},
pages = {},
doi = {10.3390/polym11121921},
pmid = {31766551},
issn = {2073-4360},
support = {EP/MO27325/1//Engineering and Physical Sciences Research Council/ ; EP/M027325/1//Engineering and Physical Sciences Research Council/ ; },
abstract = {As the current global threat of antimicrobial resistance (AMR) persists, developing alternatives to antibiotics that are less susceptible to resistance is becoming an urgent necessity. Recent advances in biomaterials have allowed for the development and fabrication of materials with discrete surface nanotopographies that can deter bacteria from adhering to their surface. Using binary polymer blends of polystyrene (PS), poly(methyl methacrylate) (PMMA) and polycaprolactone (PCL) and varying their relative concentrations, PS/PCL, PS/PMMA and PCL/PMMA polymer demixed thin films were developed with nanoisland, nanoribbon and nanopit topographies. In the PS/PCL system, PS segregates to the air-polymer interface, with the lower solubility PCL preferring the substrate-polymer interface. In the PS/PMMA and PCL/PMMA systems, PMMA prefers the air-polymer interface due to its greater solubility and lower surface energy. The anti-adhesion efficacy of the demixed films were tested against Pseudomonas aeruginosa (PA14). PS/PCL and PCL/PMMA demixed films showed a significant reduction in cell counts adhered on their surfaces compared to pure polymer control films, while no reduction was observed in the counts adhered on PS/PMMA demixed films. While the specific morphology did not affect the adhesion, a relationship between bacterial cell and topographical surface feature size was apparent. If the surface feature was smaller than the cell, then an anti-adhesion effect was observed; if the surface feature was larger than the cell, then the bacteria preferred to adhere.},
}
@article {pmid31766547,
year = {2019},
author = {Miao, L and Guo, S and Liu, Z and Liu, S and You, G and Qu, H and Hou, J},
title = {Effects of Nanoplastics on Freshwater Biofilm Microbial Metabolic Functions as Determined by BIOLOG ECO Microplates.},
journal = {International journal of environmental research and public health},
volume = {16},
number = {23},
pages = {},
pmid = {31766547},
issn = {1660-4601},
support = {No.51421006//National Science Funds for Creative Research Groups of China/ ; },
abstract = {Nanoplastic (NP) contamination is becoming a pervasive issue as NPs, originating from microplastic particles, pose potentially harmful environmental impacts on aquatic ecosystems. The environmental hazards of NPs on microorganisms have been well documented in recent studies; however, little is known about their ecotoxicity effects on freshwater biofilms, which serve as important primary producers and decomposers and are highly connected with other ecosystem components. We investigated the effects of NPs on the microbial metabolic functions of freshwater biofilms in terms of carbon source utilization ability. Biofilm samples were collected, cultivated in a hydrodynamic flume for six weeks, and then exposed in polystyrene (PS) beads (100 nm in size) with different NP concentrations (1, 5, and 10 mg/L). BIOLOG ECO microplates were used to quantify carbon source utilization characteristics. The data were analyzed using average well-color development (AWCD), functional diversity indices, and principle component analysis (PCA). Results showed that the total carbon metabolic functions (represented by AWCD) remained constant (p > 0.05) with elevated NP concentrations, but some specific carbon sources (e.g., esters) changed in their utilization ability (p < 0.05). The microbial functional diversity (Shannon-Wiener diversity index, Simpson diversity index, and Shannon evenness index) was significantly reduced under 10 mg/L NPs (p < 0.05), indicating an inhibiting effect of NPs on biofilm metabolic diversity. This study examined NP ecotoxicity effects on microbial metabolic activities at the community level, but further studies are required to fully understand the mechanisms driving this change.},
}
@article {pmid31766008,
year = {2019},
author = {Xu, Y and Dhaouadi, Y and Stoodley, P and Ren, D},
title = {Sensing the unreachable: challenges and opportunities in biofilm detection.},
journal = {Current opinion in biotechnology},
volume = {64},
number = {},
pages = {79-84},
doi = {10.1016/j.copbio.2019.10.009},
pmid = {31766008},
issn = {1879-0429},
support = {R01 GM124436/GM/NIGMS NIH HHS/United States ; R21 AI142424/AI/NIAID NIH HHS/United States ; },
abstract = {Bacteria can attach to essentially all materials and form multicellular biofilms with high-level tolerance to antimicrobials. Detrimental biofilms are responsible for a variety of problems ranging from food and water contamination, bio-corrosion, to drug resistant infections. Besides the challenges in control, biofilms are also difficult to detect due to the lack of biofilm-specific biomarkers and methods for non-destructive imaging. In this article, we present a concise review of recent advancements in this field, with a focus on medical device-associated infections. We also discuss the technologies that have potential for non-destructive detection of bacterial biofilms.},
}
@article {pmid31762509,
year = {2019},
author = {Yaikhan, T and Chuerboon, M and Tippayatham, N and Atimuttikul, N and Nuidate, T and Yingkajorn, M and Tun, AW and Buncherd, H and Tansila, N},
title = {Indole and Derivatives Modulate Biofilm Formation and Antibiotic Tolerance of Klebsiella pneumoniae.},
journal = {Indian journal of microbiology},
volume = {59},
number = {4},
pages = {460-467},
pmid = {31762509},
issn = {0046-8991},
abstract = {Intercellular communication is a crucial process for the multicellular community in both prokaryotes and eukaryotes. Indole has been recognized as a new member of the signal molecules which enables the regulated control of various bacterial phenotypes. To elucidate the inter-species relationship among enteric microorganisms via indole signaling, Klebsiella pneumoniae (KP) culture was treated with indole solution and examined for the pathogenicity by using various phenotypic tests. Both synthetic and naturally-produced indole preparations had no deteriorating effect on growth and autoaggregative capacity of KP. The results showed that biofilm formation of carbapenem-susceptible K. pneumoniae (KP-S) was clearly induced by indole exposure (≈ 2-10 folds), whereas no significant difference was observed in the resistant counterpart. In addition, the tolerance to β-lactam antibiotics of KP was altered upon exposure to indole and/or derivatives assessed by Kirby-Bauer disk diffusion test. Taken together, our finding indicates the functional role of indole in changing or modulating pathogenic behaviors of other bacteria.},
}
@article {pmid31762256,
year = {2019},
author = {Liu, XY and Guo, S and Ramoji, A and Bocklitz, T and Rösch, P and Popp, J and Yu, HQ},
title = {Spatiotemporal Organization of Biofilm Matrix Revealed by Confocal Raman Mapping Integrated with Non-negative Matrix Factorization Analysis.},
journal = {Analytical chemistry},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.analchem.9b02593},
pmid = {31762256},
issn = {1520-6882},
abstract = {Biofilms are microbial aggregates of microorganisms surrounded by a hydrogel-like matrix formed by extracellular polymeric substances (EPS). The formation of biofilms is intrinsically complex, from the attachment of microbial cells to the dispersion of the biofilm. Meanwhile, the three-dimensional framework built up by EPS changes with time and protects the microorganisms against environmental stress. Simultaneously acquiring chemical and structural information within the biofilm matrix is vital for the cognition and regulation of biofilms, yet it remains a great challenge due to the sample complexity and the limited approaches. In this study, confocal Raman microscopy and non-negative matrix factorization (NMF) analysis were combined to investigate spatiotemporal organization of Escherichia coli biofilms during development at molecular-level detail. The alternating non-negative least-squares (ANLS) approach was incorporated with the sequential coordinate-wise descent (SCD) algorithm to realize the NMF analysis for the large-scale hyperspectral data set. As a result, three components, including bacteria, protein, and polyhydroxybutyrate (PHB), were successfully resolved from the spectra of E. coli biofilm. Furthermore, the structural changes of biofilms could be visualized and quantified by their abundances derived from the NMF analysis, which might be related to the nutrient and oxygen gradient and physiological functions. This methodology provides a comprehensive understanding of the chemical constituents and their spatiotemporal distribution within the biofilm matrix. Furthermore, it also shows great potential for the analysis of unknown and complex biological samples with 3D Raman mapping.},
}
@article {pmid31759700,
year = {2019},
author = {Dai, C and Bin, L and Tang, B and Li, P and Huang, S and Fu, F and Yin, Q},
title = {Promoting the granulation process of aerobic granular sludge in an integrated moving bed biofilm-membrane bioreactor under a continuous-flowing mode.},
journal = {The Science of the total environment},
volume = {},
number = {},
pages = {135482},
doi = {10.1016/j.scitotenv.2019.135482},
pmid = {31759700},
issn = {1879-1026},
abstract = {This investigation demonstrated that aerobic granular sludge (AGS) could be cultivated rapidly in a single continuous-flowing membrane bioreactor (MBR) by introducing freely moved bio-carriers with a filling ratio of 10%. By operating the bioreactor for 28 days, AGS was successfully cultivated and kept stable for >2 months with a compact structure and clear shape, in which, extracellular polymeric substances played a key role in maintaining the stability of granular sludge structure. The microbial composition between AGS and attached biofilm was quite different, which indicated that the introduced bio-carriers improved the biodiversity within the bioreactor. Additionally, an explicit internal circulation was formed by the introduced bio-carriers, which was the main reason leading to the rapid formation of AGS. This is an interesting discovery and a novel approach to promote the rapid granulation of biomass in an MBR. Moreover, combining the biodegradation of AGS and filtration of membrane module, the bio-reactor achieved an excellent performance in removing CODCr (>90%) and TN (>85%) during the whole process.},
}
@article {pmid31758171,
year = {2019},
author = {Casagrande Pierantoni, D and Roscini, L and Corte, L and Bernardo, M and Bassetti, M and Tascini, C and Cardinali, G},
title = {Qualitative and quantitative change of the tolerance to liposomal amphotericin B triggered by biofilm maturation in C. parapsilosis.},
journal = {Medical mycology},
volume = {},
number = {},
pages = {},
doi = {10.1093/mmy/myz113},
pmid = {31758171},
issn = {1460-2709},
abstract = {Candida parapsilosis is an emerging opportunistic pathogen present in both clinical and natural environment, with a strong frequency of biofilm forming strains. While the drugs active against biofilm are rare, liposomal amphotericin B is credited with an antibiofilm activity in some opportunistic species of the genus Candida. Using freshly isolated strains from hospital environment, in this paper we could show the prevalence of biofilm forming vs. nonbiofilm forming strains. The former displayed a large variability in terms of biofilm biomass and metabolic activity. Liposomal amphotericin B minimum inhibitory concentration (MIC) of planktonic cells was below the breakpoint, whereas the sessile cells MIC (SMIC) was 1 or 2 orders of magnitude above the planktonic MIC. When the drug was applied to freshly attached cells, that is, biofilm in formation, the MIC (called SDMIC) was even below the MIC value. All resistance metrics (MIC, SMIC, and SDMIC) were quite variable although no correlation could be detected between them and the metrics used to quantify biofilm activity and biomass production. These findings demonstrate that young biofilm cells are even more susceptible than planktonic cells and that early treatments with this drug can be beneficial in cases of prosthesis implantation or especially when there is the necessity of a CVC reimplantation during a sepsis.},
}
@article {pmid31757539,
year = {2019},
author = {Xiao, W and Xu, G},
title = {Mass transfer of nanobubble aeration and its effect on biofilm growth: Microbial activity and structural properties.},
journal = {The Science of the total environment},
volume = {},
number = {},
pages = {134976},
doi = {10.1016/j.scitotenv.2019.134976},
pmid = {31757539},
issn = {1879-1026},
abstract = {It is necessary to improve the performance and reduce the aeration cost is of wastewater treatment by aerobic biofilm systems. Nanobubble aeration is supposed to be a promising method to achieve these goals. Compared with coarse bubbles, dissolved oxygen profiling showed that the nanobubbles provided more oxygen to biofilms, offering superior oxygen supply capacity and 1.5 times higher oxygen transfer efficiency. Nanobubble aeration accelerated the growth of the biofilm and achieved better removal efficiencies of chemical oxygen demand and ammonia, with as maximum as six times higher dehydrogenase activity, and more extracellular polymeric substance content than when using the traditional aeration mode. This is attributed to the enhancement of metabolism and the proliferation of microorganisms. Confocal laser-scanning microscopy imaging confirmed that nanobubble aeration affected the components of biofilm by shifting the microbial community and changing its metabolic pathways of biofilms, such as carbohydrate synthesis. Nanobubble aeration resulted in an energy saving of approximately 80%. The assessment of nanobubble aerated biofilm growth suggests that this technique can offer a rapid-initiation, high efficiency, and low-cost strategy for aerobic biofilm systems in wastewater treatment.},
}
@article {pmid31756969,
year = {2019},
author = {Hiltunen, AK and Savijoki, K and Nyman, TA and Miettinen, I and Ihalainen, P and Peltonen, J and Fallarero, A},
title = {Structural and Functional Dynamics of Staphylococcus aureus Biofilms and Biofilm Matrix Proteins on Different Clinical Materials.},
journal = {Microorganisms},
volume = {7},
number = {12},
pages = {},
doi = {10.3390/microorganisms7120584},
pmid = {31756969},
issn = {2076-2607},
support = {Personal grant to A.H.//Finnish Pharmaceutical Society/ ; Personal grant to A.H.//DOCTORAL PROGRAMME IN DRUG RESEARCH (DPDR)/ ; Research Grant awarded to A.F.//JANE AND AATOS ERKKO FOUNDATION/ ; 272266, 282981, 292646, 272363//Academy of Finland/ ; },
abstract = {Medical device-associated staphylococcal infections are a common and challenging problem. However, detailed knowledge of staphylococcal biofilm dynamics on clinically relevant surfaces is still limited. In the present study, biofilm formation of the Staphylococcusaureus ATCC 25923 strain was studied on clinically relevant materials-borosilicate glass, plexiglass, hydroxyapatite, titanium and polystyrene-at 18, 42 and 66 h. Materials with the highest surface roughness and porosity (hydroxyapatite and plexiglass) did not promote biofilm formation as efficiently as some other selected materials. Matrix-associated poly-N-acetyl-β-(1-6)-glucosamine (PNAG) was considered important in young (18 h) biofilms, whereas proteins appeared to play a more important role at later stages of biofilm development. A total of 460 proteins were identified from biofilm matrices formed on the indicated materials and time points-from which, 66 proteins were proposed to form the core surfaceome. At 18 h, the appearance of several r-proteins and glycolytic adhesive moonlighters, possibly via an autolysin (AtlA)-mediated release, was demonstrated in all materials, whereas classical surface adhesins, resistance- and virulence-associated proteins displayed greater variation in their abundances depending on the used material. Hydroxyapatite-associated biofilms were more susceptible to antibiotics than biofilms formed on titanium, but no clear correlation between the tolerance and biofilm age was observed. Thus, other factors, possibly the adhesive moonlighters, could have contributed to the observed chemotolerant phenotype. In addition, a protein-dependent matrix network was observed to be already well-established at the 18 h time point. To the best of our knowledge, this is among the first studies shedding light into matrix-associated surfaceomes of S. aureus biofilms grown on different clinically relevant materials and at different time points.},
}
@article {pmid31756896,
year = {2019},
author = {Rodríguez-Campos, D and Rodríguez-Melcón, C and Alonso-Calleja, C and Capita, R},
title = {Persistent Listeria monocytogenes Isolates from a Poultry-Processing Facility Form more Biofilm but Do Not Have a Greater Resistance to Disinfectants Than Sporadic Strains.},
journal = {Pathogens (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/pathogens8040250},
pmid = {31756896},
issn = {2076-0817},
support = {RTI2018-098267-R-C33//Ministerio de Ciencia, Innovación y Universidades/ ; LE164G18//Consejería de Educación, Junta de Castilla y León/ ; },
abstract = {Some strains of Listeria monocytogenes can persist in food-processing environments, increasing the likelihood of the contamination of foodstuffs. To identify traits that contribute to bacterial persistence, a selection of persistent and sporadic L. monocytogenes isolates from a poultry-processing facility was investigated for biofilm-forming ability (crystal violet assay). The susceptibility of sessile cells to treatments (five minutes) with sodium hypochlorite having 10% active chlorine (SHY: 10,000 ppm, 25,000 ppm, and 50,000 ppm) and benzalkonium chloride (BZK: 2500 ppm, 10,000 ppm, and 25,000 ppm) was also studied. All isolates exhibited biofilm formation on polystyrene. Persistent strains showed larger (p < 0.001) biofilm formation (OD580 = 0.301 ± 0.097) than sporadic strains (OD580 = 0.188 ± 0.082). A greater susceptibility to disinfectants was observed for biofilms of persistent strains than for those of sporadic strains. The application of SHY reduced biofilms only for persistent strains. BZK increased OD580 in persistent strains (2500 ppm) and in sporadic strains (all concentrations). These results indicate that the use of BZK at the concentrations tested could represent a public health risk. Findings in this work suggest a link between persistence and biofilm formation, but do not support a relationship between persistence and the resistance of sessile cells to disinfectants.},
}
@article {pmid31756873,
year = {2019},
author = {Lee, J and Alrashed, W and Engel, K and Yoo, K and Neufeld, JD and Lee, HS},
title = {Methane-based denitrification kinetics and syntrophy in a membrane biofilm reactor at low methane pressure.},
journal = {The Science of the total environment},
volume = {695},
number = {},
pages = {133818},
doi = {10.1016/j.scitotenv.2019.133818},
pmid = {31756873},
issn = {1879-1026},
mesh = {Biofilms ; Bioreactors/microbiology ; Denitrification ; Methane/*metabolism ; Waste Disposal, Fluid/methods ; Waste Water/microbiology ; },
abstract = {A methane-based membrane biofilm reactor (MBfR) was assessed for a tertiary nitrogen removal process in domestic wastewater treatment. To mitigate effluent dissolved methane concentrations, the MBfR was operated with a 20% methane mixing ratio and a low pressure of 0.003 atm. The nitrate concentration was reduced from 20 to 4 mg/L with a low methane concentration of 3.3 mg/L in the effluent at 4 h hydraulic retention time (HRT). An in situ dissolved oxygen sensor showed a concentration of 0.045 mg/L in the MBfR, demonstrating methane oxidation under hypoxic conditions. Both 16S rRNA gene sequencing and metagenomic analysis identified bacteria capable of oxidation of methane coupled to denitrification (Methylocystis), whereas other bacteria were implicated in either methane oxidation (Methylococcus) or nitrate reduction (Escherichia). Reduced genetic potential for nitrate reduction to nitrite at a shorter HRT coincided with a decreased efficiency of denitrification, suggesting rate limitation by this initial step of denitrification. Genes encoding nitrite reduction to dinitrogen were at similar relative abundance under both HRT conditions. Our results provide mechanistic evidence for microbial syntrophy between aerobic methanotrophs and denitrifiers in methane-fed MBfRs operated under varying HRTs, with important implications for novel biological nitrogen removal to dilute wastewater.},
}
@article {pmid31754470,
year = {2019},
author = {Davidson, DJ and Spratt, D and Liddle, AD},
title = {Implant materials and prosthetic joint infection: the battle with the biofilm.},
journal = {EFORT open reviews},
volume = {4},
number = {11},
pages = {633-639},
pmid = {31754470},
issn = {2058-5241},
abstract = {Prosthetic joint infection (PJI) is associated with poor clinical outcomes and is expensive to treat.Although uncommon overall (affecting between 0.5% and 2.2% of cases), PJI is one of the most commonly encountered complications of joint replacement and its incidence is increasing, putting a significant burden on healthcare systems.Once established, PJI is extremely difficult to eradicate as bacteria exist in biofilms which protect them from antibiotics and the host immune response.Improved understanding of the microbial pathology in PJI has generated potential new treatment strategies for prevention and eradication of biofilm associated infection including modification of implant surfaces to prevent adhesion of bacteria.Much research is currently ongoing looking at different implant surface coatings and modifications, and although most of this work has not translated into clinical medicine there has been some early clinical success. Cite this article: EFORT Open Rev 2019;4:633-639. DOI: 10.1302/2058-5241.4.180095.},
}
@article {pmid31753409,
year = {2020},
author = {Zhang, ZY and Sun, Y and Zheng, YD and He, W and Yang, YY and Xie, YJ and Feng, ZX and Qiao, K},
title = {A biocompatible bacterial cellulose/tannic acid composite with antibacterial and anti-biofilm activities for biomedical applications.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {106},
number = {},
pages = {110249},
doi = {10.1016/j.msec.2019.110249},
pmid = {31753409},
issn = {1873-0191},
abstract = {Biofilm-associated infections are in a high rate of recurrence and biofilms show formidable resistance to current antibiotics, making them a growing challenge in biomedical field. In this study, a biocompatible composite was developed by incorporating tannic acid (TA) and MgCl2 to bacterial cellulose (BC) for antimicrobial and anti-biofilm purposes. The morphology was investigated by scanning electron microscopy (SEM), and chemical structure were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectra (XPS). In vitro release profiles of tannic acid revealed that the Mg2+ cross-links help impede the release of TA from BC matrix, while composite BC-TA lacked Mg2+ ionic cross-links, thus more TA was released from the hydrogel. The BC-TA-Mg composites also displayed strong antibacterial activity against S. aureus, E. coli and P. aeruginosa. Moreover, the composites significantly reduced biofilm formation of S. aureus and P. aeruginosa after 24 h incubation by ∼80% and ∼87%, respectively. As a consequence, the BC-TA-Mg composites are a very promising material for combating biofilm-associated infections in biomedical and public health fields.},
}
@article {pmid31752996,
year = {2019},
author = {Deveaux, W and Selvarajoo, K},
title = {Searching for simple rules in Pseudomonas aeruginosa biofilm formation.},
journal = {BMC research notes},
volume = {12},
number = {1},
pages = {763},
pmid = {31752996},
issn = {1756-0500},
abstract = {OBJECTIVE: Living cells display complex and non-linear behaviors, especially when posed to environmental threats. Here, to understand the self-organizing cooperative behavior of a microorganism Pseudomonas aeruginosa, we developed a discrete spatiotemporal cellular automata model based on simple physical rules, similar to Conway's game of life.<br><br>RESULTS: The time evolution model simulations were experimentally verified for P. aeruginosa biofilm for both control and antibiotic azithromycin (AZM) treated condition. Our model suggests that AZM regulates the single cell motility, thereby resulting in delayed, but not abolished, biofilm formation. In addition, the model highlights the importance of reproduction by cell to cell interaction is key for biofilm formation. Overall, this work highlights another example where biological evolutionary complexity may be interpreted using rules taken from theoretical disciplines.},
}
@article {pmid31752382,
year = {2019},
author = {Reza, A and Sutton, JM and Rahman, KM},
title = {Effectiveness of Efflux Pump Inhibitors as Biofilm Disruptors and Resistance Breakers in Gram-Negative (ESKAPEE) Bacteria.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/antibiotics8040229},
pmid = {31752382},
issn = {2079-6382},
abstract = {Antibiotic resistance represents a significant threat to the modern healthcare provision. The ESKAPEE pathogens (Enterococcus faecium., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacterbaumannii, Pseudomonas aeruginosa, Enterobacter spp. and Escherichia coli), in particular, have proven to be especially challenging to treat, due to their intrinsic and acquired ability to rapidly develop resistance mechanisms in response to environmental threats. The development of biofilm has been characterised as an essential contributing factor towards antimicrobial-resistance and tolerance. Several studies have implicated the involvement of efflux pumps in antibiotic resistance, both directly, via drug extrusion and indirectly, through the formation of biofilm. As a result, the underlying mechanism of these pumps has attracted considerable interest due to the potential of targeting these protein structures and developing novel adjunct therapies. Subsequent investigations have revealed the ability of efflux pump-inhibitors (EPIs) to block drug-extrusion and disrupt biofilm formation, thereby, potentiating antibiotics and reversing resistance of pathogen towards them. This review will discuss the potential of EPIs as a possible solution to antimicrobial resistance, examining different challenges to the design of these compounds, with an emphasis on Gram-negative ESKAPEE pathogens.},
}
@article {pmid31750272,
year = {2019},
author = {I H, SS and F A, J and H H, Y and M E, M},
title = {Evaluation of Wi-Fi Radiation Effects on Antibiotic Susceptibility, Metabolic Activity and Biofilm Formation by Escherichia Coli 0157H7, Staphylococcus Aureus and Staphylococcus Epidermis.},
journal = {Journal of biomedical physics &amp; engineering},
volume = {9},
number = {5},
pages = {579-586},
pmid = {31750272},
issn = {2251-7200},
abstract = {Background: The radiation emitted from electromagnetic fields (EMF) can cause biological effects on prokaryotic and eukaryotic cells, including non-thermal effects.<br><br>Objective: The present study evaluated the non-thermal effects of wireless fidelity (Wi-Fi) operating at 2.4 GHz part of non-ionizing EMF on different pathogenic bacterial strains (Escherichia coli 0157H7, Staphylococcus aureus, and Staphylococcus epidermis). Antibiotic resistance, motility, metabolic activity and biofilm formation were examined.<br><br>Material and Methods: In this case-control, a Wi-Fi router was used as a source of microwaves and also bacterial cells were exposed to Wi-Fi radiation continuously for 24 and 48 hours. The antibiotic susceptibility was carried out using a disc diffusion method on Müller Hinton agar plates. Motility of Escherichia coli 0157H7 was conducted on motility agar plates. Cell metabolic activity and biofilm formation were performed using 3-(4, 5-Dimethylthiazol-2yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and crystal violet quantification, respectively.<br><br>Results: The exposure to Wi-Fi radiation altered motility and antibiotic susceptibility of Escherichia coli 0157H7. However, there was no effect Wi-Fi radiation on antibiotic susceptibility of Staphylococcus aureus and Staphylococcus epidermis. On the other hand, the exposed cells, as compared to the unexposed control, showed an increased metabolic activity and biofilm formation ability in Escherichia coli 0157H7, Staphylococcus aureus and Staphylococcus epidermis.<br><br>Conclusion: These results proposed that Wi-Fi exposure acted on bacteria in stressful manner by increasing antibiotic resistance and motility of Escherichia coli 0157H7, as well as enhancing biofilm formation by Escherichia coli 0157H7, Staphylococcus aureus and Staphylococcus epidermis. The findings may have implications for the management of serious diseases caused by these infectious bacteria.},
}
@article {pmid31749946,
year = {2019},
author = {Loiola, ABA and Aires, CP and Curylofo-Zotti, FA and Rodrigues Junior, AL and Souza-Gabriel, AE and Corona, SAM},
title = {The Impact of CO2 Laser Treatment and Acidulated Phosphate Fluoride on Enamel Demineralization and Biofilm Formation.},
journal = {Journal of lasers in medical sciences},
volume = {10},
number = {3},
pages = {200-206},
pmid = {31749946},
issn = {2008-9783},
abstract = {Introduction: This study evaluated the impact of CO2 laser treatment and acidulated phosphate fluoride (APF) on enamel demineralization and biofilm formation, using in vitro and in situ designs. Methods: Demineralized enamel slabs were distributed among 8 groups: placebo, placebo + continuous CO2 laser, placebo + repeated CO2 laser, placebo + ultrapulsed CO2 laser, 1.23% APF, APF + continuous CO2 laser, APF + repeated CO2 laser and APF + ultrapulsed CO2 laser. In the in vitro study, 15 enamel slabs from each group were subjected to a pH-cycling regimen for 14 days. In the cross over in situ design, 11 volunteers wore palatal appliances with demineralized enamel slabs for 2 periods of 14 days each. Drops of sucrose solution were dripped onto enamel slabs 8×/day. Biofilms formed on slabs were collected and the colony-forming units (CFU) of Streptococcus mutans and Lactobacillus were determined. Results: For both in vitro and in situ studies, there was no significant difference between treatments (P>0.05). However, all treatments increased microhardness of demineralized enamel (P<0.05). After a further in situ cariogenic challenge, with the exception of the placebo, all treatments maintained microhardness values (P<0.05). Microbiological analysis showed no difference in Streptococcus mutans (P>0.05) or Lactobacillus (P>0.05) counts between groups. Conclusion: The results suggest that APF gel combined with the CO2 laser, regardless of the pulse emission mode used, was effective in controlling enamel demineralization, but none of the tested treatments was able to prevent bacterial colonization.},
}
@article {pmid31747498,
year = {2019},
author = {Kharseeva, GG and Alieva, AA and Alekseeva, LP and Mangutov, YO and Shovkun, LA},
title = {[Cypopathic effect of diphtheria pathogen in the composition of biofilm.].},
journal = {Klinicheskaia laboratornaia diagnostika},
volume = {64},
number = {11},
pages = {681-685},
doi = {10.18821/0869-2084-2019-64-11-681-685},
pmid = {31747498},
issn = {0869-2084},
mesh = {Animals ; Asymptomatic Infections ; *Biofilms ; CHO Cells ; Corynebacterium diphtheriae/*pathogenicity ; Cricetulus ; *Diphtheria ; Diphtheria Toxin ; Humans ; },
abstract = {When the nasopharynx is colonized with toxigenic strains of the diphtheria pathogen, toxin is released, which contributes to the death of epithelial cells. But in bacterial carriers, the development of the clinical picture of the disease does not occur. This is due to the peculiarities of the state of their immune system, as well as the peculiarities of the production of diphtheria exotoxin by corynebacteria in the biofilm. Goal. Determining the nature of the cytopathic effect of C. diphtheriae as part of a biofilm in CHO-K1 cell culture. The planktonic and biofilm (120- and 720-hour) cultures of the strains were studied: C. diphtheriae gravis tox+ № 665, C. diphtheriae gravis tox+ № 6765, C. diphtheriae mitis tox+ № 269, C. diphtheriae gravis tox+ isolated from a patient with a diagnosis Localized oropharyngeal diphtheria C. diphtheriae gravis with a silent tox-gene. Biofilm (120- and 720-hour) cultures of diphtheria pathogen strains were obtained according to the Watnik method. The cytopathic effect of corynebacterial strains was studied on a CHO-K1 cell culture, taking into account in an inverted microscope. When studying the cytopathic effect of planktonic cultures of toxigenic strains of corynebacteria, it was found that the number of living CHO-K1 cells after 24 hours was insignificant (25.3±1.2%) and sharply decreased (2.5±0.5%) after 72 hours of cultivation. Under the influence of biofilm and, especially, 720-hour cultures, a different cytopathic effect dynamics was found: the number of living cells after 24 hours remained significant (82.5±2.2%), while at 72-hour it decreased to 25.0±3.0%. In the study of filtrates of planktonic and biofilm cultures of C. diphtheriae strain with a «silent» tox-gene, similar patterns were revealed. However, the number of live CHO-K1 cells when exposed to the filtrate of a 720-hour biofilm culture was significantly higher (p≤0.05) than when studying toxigenic strains of corynebacteria. Considering the nature of the cytopathic action, it was found that planktonic cultures of toxigenic strains of corynebacteria are characterized by a change in the cell monolayer, manifested by their thinning and elongation. The study of 720-hour biofilm cultures at 72-hour exposure revealed the appearance of a large number of rounded cells (63-69%). The cytopathic effect, formed under the influence of filtrates of planktonic and biofilm cultures of C. diphtheriae with a «silent» tox-gene, as well as strains of non-diphtheria corynebacteria, is characterized by rounding of cells and the formation of symplasts. In the biofilm, the intensity of the cytopathic effect of toxigenic C. diphtheriae strains and C. diphtheriae strain with a silent tox-gene decreased. CPD, manifested by thinning and lengthening of CHO-K1 cells, is associated with the action of diphtheria exotoxin, and rounding is associated with corynebacterial enzymes and, apparently, fragments of surface structures - adhesins. Decreased release of toxin and enzymes beyond the C. bihfilm matrix is a significant cause of the «asymptomatic» carriage of diphtheria.},
}
@article {pmid31744920,
year = {2019},
author = {Esoda, CN and Kuehn, MJ},
title = {Pseudomonas aeruginosa Leucine Aminopeptidase Influences Early Biofilm Composition and Structure via Vesicle-Associated Antibiofilm Activity.},
journal = {mBio},
volume = {10},
number = {6},
pages = {},
pmid = {31744920},
issn = {2150-7511},
abstract = {Pseudomonas aeruginosa, known as one of the leading causes of disease in cystic fibrosis (CF) patients, secretes a variety of proteases. These enzymes contribute significantly to P. aeruginosa pathogenesis and biofilm formation in the chronic colonization of CF patient lungs, as well as playing a role in infections of the cornea, burn wounds, and chronic wounds. We previously characterized a secreted P. aeruginosa peptidase, PaAP, that is highly expressed in chronic CF isolates. This leucine aminopeptidase is highly expressed during infection and in biofilms, and it associates with bacterial outer membrane vesicles (OMVs), structures known to contribute to virulence mechanisms in a variety of Gram-negative species and one of the major components of the biofilm matrix. We hypothesized that PaAP may play a role in P. aeruginosa biofilm formation. Using a lung epithelial cell/bacterial biofilm coculture model, we show that PaAP deletion in a clinical P. aeruginosa background alters biofilm microcolony composition to increase cellular density, while decreasing matrix polysaccharide content, and that OMVs from PaAP-expressing strains but not PaAP alone or in combination with PaAP deletion strain-derived OMVs could complement this phenotype. We additionally found that OMVs from PaAP-expressing strains could cause protease-mediated biofilm detachment, leading to changes in matrix and colony composition. Finally, we showed that the OMVs could also mediate the detachment of biofilms formed by both nonself P. aeruginosa strains and Klebsiella pneumoniae, another respiratory pathogen. Our findings represent novel roles for OMVs and the aminopeptidase in the modulation of P. aeruginosa biofilm architecture.IMPORTANCE Biofilm formation by the bacterial pathogen P. aeruginosa is known to contribute to drug resistance in nosocomial infections and chronic lung infections of cystic fibrosis patients. In order to treat these infections more successfully, the mechanisms of bacterial biofilm development must be elucidated. While both bacterially secreted aminopeptidase and outer membrane vesicles have been shown to be abundant in P. aeruginosa biofilm matrices, the contributions of each of these factors to the steps in biofilm generation have not been well studied. This work provides new insight into how these bacterial components mediate the formation of a robust, drug-resistant extracellular matrix and implicates outer membrane vesicles as active components of biofilm architecture, expanding our overall understanding of P. aeruginosa biofilm biology.},
}
@article {pmid31742958,
year = {2019},
author = {Godovalov, AP and Karpunina, TI},
title = {[The determination of biofilm composition of gram-positive bacteria.].},
journal = {Klinicheskaia laboratornaia diagnostika},
volume = {64},
number = {10},
pages = {632-634},
doi = {10.18821/0869-2084-2019-64-10-632-634},
pmid = {31742958},
issn = {0869-2084},
support = {17-44-590404 р_а//The Russian Foundation for Basic Research/ ; },
mesh = {*Biofilms ; Gram-Positive Bacteria/*classification ; Staining and Labeling ; },
abstract = {Current methods of biofilm imaging do not support a differentiated assessment of its composition, since it is not possible to establish a substrate stained with crystal violet, as this dye can form complexes with both intracellular and extracellular structures. This approach does not adequately assess the anti-biofilm effects of drugs, while the results of studying the interaction of drugs with biofilm components can ensure their most correct choice. The aim of investigation was to study the possibility of applying the original modification of the current method to determine the ratio of the cellular part and the matrix of biofilms of gram-positive microorganisms. The biofilm components were analyzed using a two-step approach, when prepared biofilms of gram-positive microorganisms were stained with crystal violet for 5 minutes, followed by fixing the dye in bacterial cells with iodine solution, and then the colored products were dissolved with 95% alcohol: matrix components for 1 minute, total biofilm for 15 minutes, after which the composition of biofilms was estimated by the formula: M=(OP1/OP15)×100, Kb=100-M, where M is the proportion of the matrix,%; Kb - the proportion of the cellular component,%; OP1 - optical density of samples, when alcohol was allowed to dissolve the colored product for no more than 1 minute; OP15 - was the optical density of samples, when alcohol is allowed to dissolve the colored product for 15 minutes. It was shown that in the composition of the biofilm formed by the collection strain, the proportion of the matrix was 13.2%, and the cellular component accounted for 86.8%. When the same strain cultivated in the presence of an antibiotic, an increase in the biofilm matrix was observed, which is probably due to the compensatory response of the microorganism to the action of the antibiotic. The proposed approach to the study of biofilms makes it possible to evaluate its component composition. Obtaining additional information in this way can provide, inter alia, an increase in the effectiveness of antimicrobial therapy while reducing the study time.},
}
@article {pmid31741645,
year = {2019},
author = {Rahdar, HA and Malekabad, ES and Dadashi, AR and Takei, E and Keikha, M and Kazemian, H and Karami-Zarandi, M},
title = {Correlation between biofilm formation and carbapenem resistance among clinical isolates of Klebsiella pneumoniae.},
journal = {Ethiopian journal of health sciences},
volume = {29},
number = {6},
pages = {745-750},
pmid = {31741645},
issn = {2413-7170},
abstract = {Background: Klebsiella pneumoniae is a Gram-negative enteric bacterium that causes nosocomial infections; this bacterium has survived from harsh condition using biofilm formation in hospital equipment and cause severe infection. In the other hand, the emergence and extension of carbapenem resistance burden among K. pneumonia producing biofilm is the current concern of public health services. There are controversial findings about this subject. The aim of this study was to evaluate the correlation between biofilm formation and resistance to carbapenem among clinical isolates of K. pneumoniae.<br><br>Methods: A total of 160 K. pneumoniae isolates were collected from various infections of hospitalized patients. The Carba NP test and molecular methods were used for detection of carbapenem resistance isolates of K. pneumonia. Subsequently, the ability for biofilm production was performed from all isolates. Finally, Correlation of biofilm formation among carbapenem resistant isolates was calculated using χ2 and Fisher's exact tests.<br><br>Results: Among K. pneumoniae isolates 42.5% have carbapenemase activity by Carba NP test, while carbapenemase genes were detected in 35.6% of isolates in amplification assay. Moreover, there are 52.5% (n= 84) of all isolates were formed a strong biofilm, while 38.1% (n= 61) and 9.3% (n= 15) of isolates were middle and weak biofilm producer, respectively. Among carbapenem resistant cases (n= 68), there are 77.9% (n= 53) and 22% (n= 15) of isolates were reported as strong and middle biofilm producer, respectively. We see a significant correlation was seen between biofilm formation ability and carbapenem resistant isolates (p-value < 0.00001).<br><br>Conclusion: The increase of carbapenem resistance burden in biofilm producing isolates of K. pneumoniae is considered as serious alert and the basic measures to combat this phenomenon is imperative.},
}
@article {pmid31741422,
year = {2019},
author = {Liu, Y and Feng, H and Chen, L and Zhang, H and Dong, X and Xiong, Q and Zhang, R},
title = {Root-secreted spermine binds to Bacillus amyloliquefaciens SQR9 histidine kinase KinD and modulates biofilm formation.},
journal = {Molecular plant-microbe interactions : MPMI},
volume = {},
number = {},
pages = {},
doi = {10.1094/MPMI-07-19-0201-R},
pmid = {31741422},
issn = {0894-0282},
abstract = {The signal molecules in root exudates that are sensed by plant growth-promoting rhizobacteria (PGPRs) are critical to regulate their root colonization. Phosphorylated Spo0A is an important global transcriptional regulator that controls colonization and sporulation in Bacillus species. In this study, we found that deletion of kinD from PGPR strain Bacillus amyloliquefaciens SQR9, encoding an original phosphate donor of Spo0A, resulted in reduced biofilm formation in root exudates compared with the wild type strain, indicating that KinD is responsible for sensing root exudates. Ligands of B. amyloliquefaciens SQR9 KinD in cucumber root exudates were determined by both the non-targeted ligand fishing method and the targeted surface plasmon resonance (SPR) detection method. In total, we screened 80 compounds in root exudates for binding to KinD and found that spermine and guanosine could bind to KinD with KD values of 213 μM and 51 μΜ, respectively. In addition, calcium L-threonate, N-acetyl-L-aspartic acid, sodium decanoic acid and parabanic acid could also bind to KinD weakly. Then, the 3-dimensional binding models were constructed to demonstrate the interactions between the root secreted signals and KinD. It was observed that exogenous spermine reduced the wrinkles of biofilm when kinD was defected, indicating that KinD might be involved in sensing root-secreted spermine and stabilizing biofilm in response to this negative effector. This study provided a new insight of interaction between rhizobacterial sensor and root secreted signals.},
}
@article {pmid31740326,
year = {2020},
author = {Fernández-Calderón, MC and Romero-Guzmán, D and Ferrández-Montero, A and Pérez-Giraldo, C and González-Carrasco, JL and Lieblich, M and Benavente, R and Ferrari, B and González-Martín, ML and Gallardo-Moreno, AM},
title = {Impact of PLA/Mg films degradation on surface physical properties and biofilm survival.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {185},
number = {},
pages = {110617},
doi = {10.1016/j.colsurfb.2019.110617},
pmid = {31740326},
issn = {1873-4367},
abstract = {New biocompatible and bioabsorbable materials are currently being developed for bone regeneration. These serve as scaffolding for controlled drug release and prevent bacterial infections. Films of polylactic acid (PLA) polymers that are Mg-reinforced have demonstrated they have suitable properties and bioactive behavior for promoting the osseointegration process. However little attention has been paid to studying whether the degradation process can alter the adhesive physical properties of the biodegradable film and whether this can modify the biofilm formation capacity of pathogens. Moreover, considering that the concentration of Mg and other corrosion products may not be constant during the degradation process, the question that arises is whether these changes can have negative consequences in terms of the bacterial colonization of surfaces. Bacteria are able to react differently to the same compound, depending on its concentration in the medium and can even become stronger when threatened. In this context, physical surface parameters such as hydrophobicity, surface tension and zeta potential of PLA films reinforced with 10% Mg have been determined before and after degradation, as well as the biofilm formation capacity of Staphylococcus epidermidis. The addition of Mg to the films makes them less hydrophobic and the degradation also reduces the hydrophobicity and increases the negative charge of the surface, especially over long periods of time. Early biofilm formation at 8 h is consistent with the physical properties of the films, where we can observe a reduction in the bacterial biofilm formation. However, after 24 h of incubation, the biofilm formation increases significantly on the PLA/Mg films with respect to PLA control. The explosive release of Mg ions and other corrosion products within the first hours were not enough to prevent a greater biofilm formation after this initial time. Consequently, the Mg addition to the polymer matrix had a bacteriostatic effect but not a bactericidal one. Future works should aim to optimize the design and biofunctionality of these promising bioabsorbable composites for a degradation period suitable for the intended application.},
}
@article {pmid31740039,
year = {2019},
author = {Pan, J and Hu, J and Liu, B and Li, J and Wang, D and Bu, C and Wang, X and Xiao, K and Liang, S and Yang, J and Hou, H},
title = {Enhanced quorum sensing of anode biofilm for better sensing linearity and recovery capability of microbial fuel cell toxicity sensor.},
journal = {Environmental research},
volume = {},
number = {},
pages = {108906},
doi = {10.1016/j.envres.2019.108906},
pmid = {31740039},
issn = {1096-0953},
abstract = {MFC toxicity sensor has major hindrances that limit its practical application, such as the poor concentration-response relationship and inferior recovery capability after high toxicity shock. Till now, the direct influence of intrinsic properties on the performance of MFC toxicity sensor has not been well understood. Quorum sensing (QS) is a cell-to-cell communication strategy that indirectly affects the intrinsic properties of electroactive biofilms. In this work, commercially available QS autoinducers (AHLs) were applied to MFC toxicity sensor to manipulate anode biofilm for better sensing performance. The results showed that the addition of AHLs (C6-HSL, 3-OXO-C12-HSL) led to higher sensing linearity to a wider range of Pb2+. The voltage of MFC sensors with AHLs addition fully recovered even after 10 mg/L Cu2+ shock, indicating an enhanced recovery capability of MFC toxicity sensor. It was found that higher live/dead cells ratio and increased exoelectrogen Geobacter abundance were responsible for the superior sensing linearity and recovery capability of MFC toxicity sensor. Our work presented a novel and effective way to advance the process of MFC toxicity sensor application from the perspective of EABs.},
}
@article {pmid31739833,
year = {2019},
author = {Ré, ACS and Ferreira, MP and Freitas, O and Aires, CP},
title = {Antimicrobial effect of a local release system containing metronidazole against a Porphyromonas gingivalis biofilm.},
journal = {Die Pharmazie},
volume = {74},
number = {11},
pages = {665-666},
doi = {10.1691/ph.2019.8241},
pmid = {31739833},
issn = {0031-7144},
abstract = {The aim of this study was to evaluate a semi-solid system containing metronidazole (MDZ) in presence of challenging conditions for drug release, as well its antimicrobial effect against Porphyromonas gingivalis biofilm. Biofilms grown in culture medium were exposed to a formulation containing MDZ or its vehicle. After 24, 48, and 72 h, biofilm viability were analyzed while MDZ was quantified in culture medium and buffer solution (control). MDZ formulation reduced bacterial viability when compared to control groups. The vehicle formulation also affected bacterial viability in relation to control at all periods. Culture medium impaired MDZ release compared to buffer solution at 24 h. The semi-solid system reported herein is able to release MDZ and maintain its levels at concentrations that control viability of P. gingivalis in 1- to 3-day-old biofilms.},
}
@article {pmid31737922,
year = {2019},
author = {Zhang, Z and Du, W and Wang, M and Li, Y and Su, S and Wu, T and Kang, Y and Shan, X and Shi, Q and Zhu, G},
title = {Contribution of the colicin receptor CirA to biofilm formation, antibotic resistance, and pathogenicity of Salmonella Enteritidis.},
journal = {Journal of basic microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1002/jobm.201900418},
pmid = {31737922},
issn = {1521-4028},
support = {C2019407070//Natural Science Foundation of Hebei Province/ ; HBCT2018130203-WSZ//Earmarked Fund for Modern Agro-Industry Technology Research System of Hebei Province/ ; 31802186//National Natural Science Foundation of China/ ; 2017M611935//China Postdoctoral Science Foundation/ ; 201602A185//Science and Technology Bureau of Qinhuangdao City/ ; 201702B001//Science and Technology Bureau of Qinhuangdao City/ ; },
abstract = {Salmonella Enteritidis is an important foodborne pathogen that can infect a wide range of animal species including human beings, resulting in great losses to commercial husbandry and human health. CirA is an outer membrane receptor involved in iron uptake and colicin1A/B-mediated competitive killing. Although iron uptake is crucial to bacterial virulence, limited literature is available about the role of CirA in infection. In the present work, we aimed to evaluate the role of CirA during S. Enteritidis infection. For this purpose, we generated a CirA-deficient mutant of the S. Enteritidis strain C50336 and examined its biological characteristics. The results showed that cirA gene inactivation caused sharply decreased biofilm formation and apparently impaired antibiotic resistance. Furthermore, the cirA gene deletion mutant showed markedly reduced adhesion and invasion to human epithelial cell line Caco-2 cells and decreased proliferation in mouse macrophage cell line RAW264.7 cells. Moreover, attenuated virulence was determined by a mouse model, with an LD50 increase of approximately 1,000-fold. These data indicated that CirA plays critical roles in the S. Enteritidis infection process.},
}
@article {pmid31737611,
year = {2019},
author = {Qvortrup, K and Hultqvist, LD and Nilsson, M and Jakobsen, TH and Jansen, CU and Uhd, J and Andersen, JB and Nielsen, TE and Givskov, M and Tolker-Nielsen, T},
title = {Small Molecule Anti-biofilm Agents Developed on the Basis of Mechanistic Understanding of Biofilm Formation.},
journal = {Frontiers in chemistry},
volume = {7},
number = {},
pages = {742},
pmid = {31737611},
issn = {2296-2646},
abstract = {Microbial biofilms are the cause of persistent infections associated with various medical implants and distinct body sites such as the urinary tract, lungs, and wounds. Compared with their free living counterparts, bacteria in biofilms display a highly increased resistance to immune system activities and antibiotic treatment. Therefore, biofilm infections are difficult or impossible to treat with our current armory of antibiotics. The challenges associated with biofilm infections have urged researchers to pursue a better understanding of the molecular mechanisms that are involved in the formation and dispersal of biofilms, and this has led to the identification of several steps that could be targeted in order to eradicate these challenging infections. Here we describe mechanisms that are involved in the regulation of biofilm development in Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii, and provide examples of chemical compounds that have been developed to specifically inhibit these processes. These compounds include (i) pilicides and curlicides which inhibit the initial steps of biofilm formation by E. coli; (ii) compounds that interfere with c-di-GMP signaling in P. aeruginosa and E. coli; and (iii) compounds that inhibit quorum-sensing in P. aeruginosa and A. baumannii. In cases where compound series have a defined molecular target, we focus on elucidating structure activity relationship (SAR) trends within the particular compound series.},
}
@article {pmid31736897,
year = {2019},
author = {Roussin, M and Rabarioelina, S and Cluzeau, L and Cayron, J and Lesterlin, C and Salcedo, SP and Bigot, S},
title = {Identification of a Contact-Dependent Growth Inhibition (CDI) System That Reduces Biofilm Formation and Host Cell Adhesion of Acinetobacter baumannii DSM30011 Strain.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2450},
pmid = {31736897},
issn = {1664-302X},
abstract = {Acinetobacter baumannii is a multidrug-resistant nosocomial opportunistic pathogen that is becoming a major health threat worldwide. In this study, we have focused on the A. baumannii DSM30011 strain, an environmental isolate that retains many virulence-associated traits. We found that its genome contains two loci encoding for contact-dependent growth inhibition (CDI) systems. These systems serve to kill or inhibit the growth of non-sibling bacteria by delivering toxins into the cytoplasm of target cells, thereby conferring the host strain a significant competitive advantage. We show that one of the two toxins functions as a DNA-damaging enzyme, capable of inducing DNA double-stranded breaks to the chromosome of Escherichia coli strain. The second toxin has unknown catalytic activity but stops the growth of E. coli without bactericidal effect. In our conditions, only one of the CDI systems was highly expressed in the A. baumannii DSM30011 strain and was found to mediate interbacterial competition. Surprisingly, the absence of this CDI system promotes adhesion of A. baumannii DSM30011 to both abiotic and biotic surfaces, a phenotype that differs from previously described CDI systems. Our results suggest that a specific regulation mediated by this A. baumannii DSM30011 CDI system may result in changes in bacterial physiology that repress host cell adhesion and biofilm formation.},
}
@article {pmid31734609,
year = {2020},
author = {Gani, KM and Nazir, FU and Kumari, S and Bux, F and Kazmi, AA},
title = {Role of treatment configuration in simultaneous removal of priority phthalic acid esters and nitrogen in a post anoxic integrated biofilm activated sludge system.},
journal = {The Science of the total environment},
volume = {702},
number = {},
pages = {134733},
doi = {10.1016/j.scitotenv.2019.134733},
pmid = {31734609},
issn = {1879-1026},
abstract = {To develop future wastewater treatment systems, focus is to improve/investigate existing biological wastewater treatment processes for the concurrent treatment of conventional pollution parameters (essentially nitrogen) and micro pollutants. Majority of the existing biological wastewater treatment systems were not designed for the removal of micro pollutants. This study focuses on understanding the role of treatment configuration for efficient removal of nitrogen and priority phthalic acid esters (PAEs) from real municipal wastewater in an integrated biofilm activated sludge (IBAS) system. The reactor was operated in two phases: Run I, without external carbon source in anoxic reactor and Run II, a nitrogen removal process, with partial diversion of untreated wastewater in anoxic reactor. Nitrogen removal was 70 ± 12% in both operational phases, however, during Run I, removal of PAEs fluctuated with an average removal of 60-78%. Comparatively, removal of PAEs in Run II varied over a smaller range with average removal increased to 89-95%. In both operational scenarios, secondary oxic tank contributed maximum to the overall removal of PAEs in treatment system. Mass balance calculations showed significant contribution of biodegradation towards overall removal of PAEs which was enhanced by the supply of external carbon source. Kinetics and model output supported the PAEs removal performance observed in different reaction environments of IBAS process. A correlation between food to microorganism (F/M) ratio and PAEs removal showed increase in PAEs removal with decrease in F/M ratio. The study showed that treatment configuration and F/M ratio may be one of the guiding parameters for efficient removal of PAEs in biological wastewater treatment.},
}
@article {pmid31734360,
year = {2019},
author = {Wang, SH and Chen, CC and Lee, CH and Chen, XA and Chang, TY and Cheng, YC and Young, JJ and Lu, JJ},
title = {Fungicidal and anti-biofilm activities of trimethylchitosan-stabilized silver nanoparticles against Candida species in zebrafish embryos.},
journal = {International journal of biological macromolecules},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijbiomac.2019.10.002},
pmid = {31734360},
issn = {1879-0003},
abstract = {Herein, positively surface-charged silver nanoparticles (AgNPs) capped with trimethylchitosan nitrate (TMCN) were synthesized using an environmentally friendly method. Nano-sized TMCN-AgNPs (~80 nm) with high zeta potential (>30 mV) provide sufficient static repulsion to stabilize colloid AgNPs in aqueous solutions without aggregation for >3 months. In in vitro cell cycle assays, TMCN-AgNPs showed low cytotoxicity towards L929 cells. A microdilution inhibition assay demonstrated the antifungal potential of TMCN-AgNPs, with a minimum inhibitory concentration of 0.06 mM against Candida tropicalis ATCC 750, and 0.46 mM against both Candida albicans ATCC 76615 and Candida glabrata ATCC 15545. Moreover, the addition of TMCN-AgNPs at 0.23 mM significantly reduced biofilm formation in 96-well plates with C. albicans and C. tropicalis. Importantly, when zebrafish eggs were infected with Candida cells, 0.23 mM TMCN-AgNPs greatly diminished the amount of biofilm on eggs and rescued the survival of embryos by up to 70%.},
}
@article {pmid31733924,
year = {2019},
author = {Barnier, C and Clerissi, C and Lami, R and Intertaglia, L and Lebaron, P and Grimaud, R and Urios, L},
title = {Description of Palleronia rufa sp. nov., a biofilm-forming and AHL-producing Rhodobacteraceae, reclassification of Hwanghaeicola aestuarii as Palleronia aestuarii comb. nov., Maribius pontilimi as Palleronia pontilimi comb. nov., Maribius salinus as Palleronia salina comb. nov., Maribius pelagius as Palleronia pelagia comb. nov. and emended description of the genus Palleronia.},
journal = {Systematic and applied microbiology},
volume = {},
number = {},
pages = {126018},
doi = {10.1016/j.syapm.2019.126018},
pmid = {31733924},
issn = {1618-0984},
abstract = {Strain MOLA 401T was isolated from marine waters in the southwest lagoon of New Caledonia and was shown previously to produce an unusual diversity of quorum sensing signaling molecules. This strain was Gram-negative, formed non-motile cocci and colonies were caramel. Optimum growth conditions were 30°C, pH 8 and 3% NaCl (w/v). Based on 16S rRNA gene sequence analysis, this strain was found to be closely related to Pseudomaribius aestuariivivens NBRC 113039T (96.9% of similarity), Maribius pontilimi DSM 104950T (96.4% of similarity) and Palleronia marisminoris LMG 22959T (96.3% of similarity), belonging to the Roseobacter group within the family Rhodobacteraceae. As its closest relatives, strain MOLA 401T is able to form a biofilm on polystyrene, supporting the view of Roseobacter group strains as prolific surface colonizers. An in-depth genomic study allowed us to affiliate strain MOLA 401T as a new species of genus Palleronia and to reaffiliate some of its closest relatives in this genus. Consequently, we describe strain MOLA 401T (DSM 106827T=CIP 111607T=BBCC 401T) for which we propose the name Palleronia rufa sp. nov. We also propose to emend the description of the genus Palleronia and to reclassify Maribius and Hwanghaeicola species as Palleronia species.},
}
@article {pmid31732413,
year = {2020},
author = {Sun, Z and Ding, C and Xi, J and Lu, L and Yang, B},
title = {Enhancing biofilm formation in biofilters for benzene, toluene, ethylbenzene, and xylene removal by modifying the packing material surface.},
journal = {Bioresource technology},
volume = {296},
number = {},
pages = {122335},
doi = {10.1016/j.biortech.2019.122335},
pmid = {31732413},
issn = {1873-2976},
mesh = {Benzene ; Benzene Derivatives ; Biodegradation, Environmental ; Biofilms ; Extracellular Polymeric Substance Matrix ; *Toluene ; *Xylenes ; },
abstract = {Polyurethane (PU) sponges are popular packing material in biofilters and their smooth and hydrophobic surface often leads to an uneven distribution and detachment of biofilms. In this work, the surface of PU sponge was modified to obtain higher roughness and positive charge. The performances of two biofilters (BF1 with pristine sponge and BF2 with modified sponge) for benzene, toluene, ethylbenzene, and xylene (BTEX) removal were investigated. Total Volatile Organic Compound (TVOC) removal efficiency and CO2 increment were 61% and 804 ppm for BF2 respectively after start-up, compared with 51% and 538 ppm for BF1. Analysis on biofilms showed that the modification of PU sponge significantly improved the microbial growth, viability and adhesive strength in biofilms, reduced extracellular polymeric substance (EPS) and changed the microbial community. These results demonstrate that modified sponge can enhance biofilm formation and BTEX removal in biofilters and may applied in large-scale applications.},
}
@article {pmid31731396,
year = {2019},
author = {Choi, HW and Park, SY and Kang, MK and Shon, WJ},
title = {Comparative Analysis of Biofilm Removal Efficacy by Multisonic Ultracleaning System and Passive Ultrasonic Activation.},
journal = {Materials (Basel, Switzerland)},
volume = {12},
number = {21},
pages = {},
pmid = {31731396},
issn = {1996-1944},
support = {H18C1234//Korean Health Technology R&amp;D Project KHIDI/ ; 01-2016-0008//Seoul National University Dental Hospital/ ; },
abstract = {The purpose of this study was to compare disinfection and the biofilm removal efficacy of the GentleWave System (Sonendo, Inc., Laguna Hills, CA, USA) with passive ultrasonic activation method. Forty-seven freshly extracted human molars were inoculated with Enterococcus faecalis and cultured for five weeks to establish biofilm. Eight molars were tested for confirmation of infection. Four of the eight teeth were not inoculated in order to provide a negative control. The remaining 39 inoculated molars were randomly separated into three treatment groups (n = 13 per group): Group 1-no treatment, Group 2-conventional rotary instrumentation and passive ultrasonic activation, and Group 3-minimal instrumentation and the GentleWave System treatment. Roots were subsequently prepared per standard histological tissue processing procedures. Modified Brown and Brenn stained sections and Hematoxylin and Eosin stained sections were visualized at 4× and 13.5× magnification using a stereomicroscope. The sections were scored and blindly analyzed by two independent evaluators, including a histopathologist, to evaluate the presence of biofilm on canal wall. A significant difference was found between Group 2 and Group 3 in both apical and middle regions (p = 0.001) of the mesial roots of mandibular molars and mesiobuccal roots of maxillary molars. Group 3 revealed significantly less biofilm than the controls (p = 0.003). The GentleWave System demonstrated significantly greater reduction in biofilm within the mesial roots of mandibular molars and mesiobuccal roots of maxillary molars than those treated with conventional rotary instrumentation and passive ultrasonic activation protocol.},
}
@article {pmid31728266,
year = {2019},
author = {Azimi, L and Lari, AR},
title = {Colistin-resistant Pseudomonas aeruginosa clinical strains with defective biofilm formation.},
journal = {GMS hygiene and infection control},
volume = {14},
number = {},
pages = {Doc12},
pmid = {31728266},
issn = {2196-5226},
abstract = {Aim: Colistin is the only effective antibiotic in some cases of Pseudomonasaeruginosa resistance to all tested antibiotics, even carbapenem. On the other hand, biofilm formation is one of the antibiotic resistance mechanisms in this bacterium. The aim of this study was to examine biofilm formation in colistin-resistant P. aeruginosa for the first time. Method: Two groups of P. aeruginosa were included in this study: 1) colistin-resistant and 2) colistin-susceptible. Biofilm formation was determined in these groups using the micro-tube test well as PCR to detect the genes involved in biofilm formation (ppk and molA). The plasmids for colistin resistance, mcr-1 and mcr-2, were also determined. P. aeruginosa ATCC 27853 was used as a control for all tests. Results: Strong biofilm formation was observed only in colistin-susceptible strains, and ppk and modA were not detected in colistin-resistant strains. The control strain P. aeruginosa ATCC 27853 possesses ppk and modA and is categorized as a strong biofilm formation group. According to the results of this study, colistin resistance is associated with defective biofilm formation, as reported by other studies on Acinetobacter baumannii.},
}
@article {pmid31728201,
year = {2019},
author = {Penesyan, A and Nagy, SS and Kjelleberg, S and Gillings, MR and Paulsen, IT},
title = {Rapid microevolution of biofilm cells in response to antibiotics.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {34},
pmid = {31728201},
issn = {2055-5008},
abstract = {Infections caused by Acinetobacter baumannii are increasingly antibiotic resistant, generating a significant public health problem. Like many bacteria, A. baumannii adopts a biofilm lifestyle that enhances its antibiotic resistance and environmental resilience. Biofilms represent the predominant mode of microbial life, but research into antibiotic resistance has mainly focused on planktonic cells. We investigated the dynamics of A. baumannii biofilms in the presence of antibiotics. A 3-day exposure of A. baumannii biofilms to sub-inhibitory concentrations of antibiotics had a profound effect, increasing biofilm formation and antibiotic resistance in the majority of biofilm dispersal isolates. Cells dispersing from biofilms were genome sequenced to identify mutations accumulating in their genomes, and network analysis linked these mutations to their phenotypes. Transcriptomics of biofilms confirmed the network analysis results, revealing novel gene functions of relevance to both resistance and biofilm formation. This approach is a rapid and objective tool for investigating resistance dynamics of biofilms.},
}
@article {pmid31727369,
year = {2019},
author = {Katoch, P and Gupta, K and Yennamalli, RM and Vashistt, J and Bisht, GS and Shrivastava, R},
title = {Random insertion transposon mutagenesis of Mycobacterium fortuitum identified mutant defective in biofilm formation.},
journal = {Biochemical and biophysical research communications},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.bbrc.2019.11.021},
pmid = {31727369},
issn = {1090-2104},
abstract = {Mycobacterium fortuitum has emerged as a nosocomial infectious agent and biofilm formation attributed for the presence of this bacterium in hospital environment. Transposon random mutagenesis was used to identify membrane-proteins for biofilm formation in M. fortuitum. Ten mutants were shortlisted from a library of 450 mutants for examine their biofilm forming ability. Comparative biofilm ability with respect to wild type M. fortuitum ATCC 6841 showed an altered and delayed biofilm formation in one mutant namely, MT721. Sequence analysis revealed mutation in anthranilate phosphoribosyl transferase (MftrpD), which is associated with tryptophan operon. Functional interaction study of TrpD protein through STRING showed its interaction with chorismate utilizing proteins, majorly involved in synthesis of aromatic amino acid and folic acid, suggesting that biofilm establishment and maintenance requires components of central metabolism. Our study indicates important role of MftrpD in establishment and maintenance of biofilm by M. fortuitum, which may further be explored for drug discovery studies against mycobacterial infections.},
}
@article {pmid31725203,
year = {2019},
author = {Bernardi, S and Karygianni, L and Filippi, A and Anderson, AC and Zürcher, A and Hellwig, E and Vach, K and Macchiarelli, G and Al-Ahmad, A},
title = {Combining culture and culture-independent methods reveals new microbial composition of halitosis patients' tongue biofilm.},
journal = {MicrobiologyOpen},
volume = {},
number = {},
pages = {e958},
doi = {10.1002/mbo3.958},
pmid = {31725203},
issn = {2045-8827},
support = {DFG, AL-1179/2-1//German Research foundation/ ; },
abstract = {BACKGROUND: Oral malodor is a very discomforting condition deriving from the presence of volatile sulfur compounds in the expired air. In halitosis of intraoral etiology, the volatile sulfur compounds are metabolic products of the oral microorganisms within the biofilm coating the tongue dorsum as well as other tissues in the oral cavity. The aim of this study was to characterize and compare the microbial composition of tongue biofilm in volunteers suffering from halitosis and healthy volunteers by means of both the culture method and culture-independent cloning technique.<br><br>RESULTS: A high bacterial variety (more than 80 different species) was detected using the combination of both methods. A distinct bacterial composition was revealed in the halitosis-associated biofilms compared with the health-associated biofilms. Actinomyces graevenitzii was shown to be significantly associated with the halitosis condition. The culture method identified 47 species, included Veillonella rogosae, never isolated from the tongue biofilm of halitosis patients so far. In the healthy condition, the culture-dependent method showed that the most frequent species were Streptococcus parasanguinis among the aerobes and Veillonella spp. among the anaerobes. The culture-independent cloning method detected more than 50 species. Streptococci, in particular S. mitis/oralis, S. pseudopneumoniae, and S. infantis as well as Prevotella spp., were found most frequently in halitosis patients. Streptococcus salivarius and Rothia mucilaginosa were found more frequently in the healthy condition.<br><br>CONCLUSIONS: The combination of the culture-dependent and culture-independent cloning techniques allowed for a widespread analysis of the tongue biofilm in halitosis patients. The results can support further pharmacological research for new antimicrobial agents and halitosis therapy strategies.},
}
@article {pmid31722994,
year = {2019},
author = {Oppy, CC and Jebeli, L and Kuba, M and Oates, CV and Strugnell, R and Edgington-Mitchell, LE and Valvano, MA and Hartland, EL and Newton, HJ and Scott, NE},
title = {Loss of O-Linked Protein Glycosylation in Burkholderia cenocepacia Impairs Biofilm Formation and Siderophore Activity and Alters Transcriptional Regulators.},
journal = {mSphere},
volume = {4},
number = {6},
pages = {},
pmid = {31722994},
issn = {2379-5042},
abstract = {O-linked protein glycosylation is a conserved feature of the Burkholderia genus. The addition of the trisaccharide β-Gal-(1,3)-α-GalNAc-(1,3)-β-GalNAc to membrane exported proteins in Burkholderia cenocepacia is required for bacterial fitness and resistance to environmental stress. However, the underlying causes of the defects observed in the absence of glycosylation are unclear. Using proteomics, luciferase reporter assays, and DNA cross-linking, we demonstrate the loss of glycosylation leads to changes in transcriptional regulation of multiple proteins, including the repression of the master quorum CepR/I. These proteomic and transcriptional alterations lead to the abolition of biofilm formation and defects in siderophore activity. Surprisingly, the abundance of most of the known glycosylated proteins did not significantly change in the glycosylation-defective mutants, except for BCAL1086 and BCAL2974, which were found in reduced amounts, suggesting they could be degraded. However, the loss of these two proteins was not responsible for driving the proteomic alterations, biofilm formation, or siderophore activity. Together, our results show that loss of glycosylation in B. cenocepacia results in a global cell reprogramming via alteration of the transcriptional regulatory systems, which cannot be explained by the abundance changes in known B. cenocepacia glycoproteins.IMPORTANCE Protein glycosylation is increasingly recognized as a common posttranslational protein modification in bacterial species. Despite this commonality, our understanding of the role of most glycosylation systems in bacterial physiology and pathogenesis is incomplete. In this work, we investigated the effect of the disruption of O-linked glycosylation in the opportunistic pathogen Burkholderia cenocepacia using a combination of proteomic, molecular, and phenotypic assays. We find that in contrast to recent findings on the N-linked glycosylation systems of Campylobacter jejuni, O-linked glycosylation does not appear to play a role in proteome stabilization of most glycoproteins. Our results reveal that loss of glycosylation in B. cenocepacia strains leads to global proteome and transcriptional changes, including the repression of the quorum-sensing regulator cepR (BCAM1868) gene. These alterations lead to dramatic phenotypic changes in glycosylation-null strains, which are paralleled by both global proteomic and transcriptional alterations, which do not appear to directly result from the loss of glycosylation per se. This research unravels the pleiotropic effects of O-linked glycosylation in B. cenocepacia, demonstrating that its loss does not simply affect the stability of the glycoproteome, but also interferes with transcription and the broader proteome.},
}
@article {pmid31721708,
year = {2019},
author = {Khan, F and Nguyen Pham, DT and Oloketuyi, SF and Kim, YM},
title = {Antibiotics and their different application strategies in controlling the biofilm forming pathogenic bacteria.},
journal = {Current pharmaceutical biotechnology},
volume = {},
number = {},
pages = {},
doi = {10.2174/1389201020666191112155905},
pmid = {31721708},
issn = {1873-4316},
abstract = {BACKGROUND: The establishment of biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. Biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of extracellular polymeric substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment.<br><br>METHODS: Up to the present, several methodologies employing antibiotics as an anti-biofilm, anti-virulence or quorum quenching agent have been developed for the biofilm inhibition and eradication of pre-formed matured biofilm.<br><br>RESULTS: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit the biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) the combination of multiple antibiotics, (2) the combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier.<br><br>CONCLUSION: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.},
}
@article {pmid31721122,
year = {2020},
author = {Van Dyck, K and Van Dijck, P and Vande Velde, G},
title = {Bioluminescence Imaging to Study Mature Biofilm Formation by Candida spp. and Antifungal Activity In Vitro and In Vivo.},
journal = {Methods in molecular biology (Clifton, N.J.)},
volume = {2081},
number = {},
pages = {127-143},
doi = {10.1007/978-1-4939-9940-8_9},
pmid = {31721122},
issn = {1940-6029},
abstract = {The widespread use of indwelling medical devices has increased the number of device-related infections in hospitalized patients. These infections are often associated with the formation of biofilms on the medical implants that are difficult to treat because of their resistance to the classical antifungal drugs. The most common fungi isolated from catheters and other medical devices are Candida species. The Candida genus contains multiple species of which C. albicans and C. glabrata are the two most common pathogenic yeasts in humans. A limited number of animal models is available for investigating host-pathogen interactions and testing novel antifungal drugs in vivo against these species. Fungal load in biofilms in these models is traditionally analyzed postmortem, requiring host sacrifice and enumeration of microorganisms from individual biofilms in order to evaluate the amount of colony forming units and the efficacy of antifungal treatment. Bioluminescence imaging (BLI) made compatible with small animal models for in vivo biofilm formation is a valuable tool to follow biofilm development and its treatment longitudinally. Due to the noninvasive nature of BLI, the imaging procedure can be repeated in the same animal, allowing for follow-up of the biofilm growth in vivo without removing the implanted device or detaching the biofilm from its substrate. Although detecting a quantifiable in vivo BLI signal from biofilms formed on the inside of implanted catheters is challenging, BLI proved to be a practical tool in the study of fungal biofilms. This method describes the use of BLI for in vitro and in vivo follow-up of device-related fungal biofilm formation in mice and rats and antifungal activity testing against both C. albicans and C. glabrata device-associated biofilms. It can further be applied for efficient in vivo screening for interesting genes of the pathogen and the host involved in biofilm formation.},
}
@article {pmid31720769,
year = {2019},
author = {Zhang, Y and Zhao, L and Song, T and Cheng, Y and Bao, M and Li, Y},
title = {Simultaneous nitrification and denitrification in an aerobic biofilm biosystem with loofah sponges as carriers for biodegrading hydrolyzed polyacrylamide-containing wastewater.},
journal = {Bioprocess and biosystems engineering},
volume = {},
number = {},
pages = {},
doi = {10.1007/s00449-019-02247-x},
pmid = {31720769},
issn = {1615-7605},
support = {2013AA064401//Major Projects of the National High Technology Research and Development Program 863/ ; 51174181//National Natural Science Foundation of China/ ; 201861016//Fundamental Research Funds for the Central Universities/ ; 2017GSF217012//Key Research and Development Program of Shandong Province (public welfare special project)/ ; },
abstract = {Simultaneous nitrification and denitrification (SND) during treating hydrolyzed polyacrylamide (HPAM) containing wastewater were explored in an aerobic biofilm reactor biosystem. Here, loofah sponges as the environment-friendly and low-cost material were applied as the carriers in this biosystem. The removal efficiencies of HPAM and total nitrogen (TN) reached 43.6% and 54.3%, respectively, after 120 days stabilized running periods. Moreover, the structure of loofah sponges affected anaerobic microenvironment significantly which was indispensable for realizing a high-performance of SND. Key microorganisms in this biosystem included nitrobacteria, denitrobacteria and HPAM-biodegrading bacteria. The abundance of nitrobacteria and denitrobacteria on the biofilm was increased by 17.2% and 15.3%, respectively, through cultivation. Meanwhile, the biotransformation mechanisms of HPAM and diverse valence of nitrogen under different chemical oxygen demand (COD)/N and dissolved oxygen (DO) conditions were investigated. When COD/N and DO were 8:1 and 2 mg/L, HPAM biodegradation, SND efficiency and TN removal achieved their maximum, and the values were 54.3%, 92.3% and 60.1%, respectively. Key enzyme activities also reached their maximum in this condition. The optimal COD/N and DO was pivotal to achieve the high-performance of SND, and it was closely correlated with HPAM biodegradation. Meanwhile, SND could facilitate the biotransformation of HPAM.},
}
@article {pmid31719975,
year = {2019},
author = {Ranjbar, R and Farahani, A},
title = {Study of genetic diversity, biofilm formation, and detection of Carbapenemase, MBL, ESBL, and tetracycline resistance genes in multidrug-resistant Acinetobacter baumannii isolated from burn wound infections in Iran.},
journal = {Antimicrobial resistance and infection control},
volume = {8},
number = {},
pages = {172},
pmid = {31719975},
issn = {2047-2994},
abstract = {Background: Antimicrobial resistance in multidrug-resistant Acinetobacter baumannii (MDR-AB) isolated from burn wound infections is a major concern in intensive care or burns units worldwide, and molecular studies are considered critical strategies for control of MDR-AB outbreaks in this regard. Thus, in this study, antibiotic resistance, biofilm-forming ability, molecular epidemiology of MDR A. baumannii strains recovered from patients with burns were investigated in three major hospital centers of Iran.<br><br>Methods: In this cross-sectional research, 163 non-repetitive A. baumannii strains were tested for susceptibility to antimicrobial agents. Polymerase chain reaction (PCR) was performed to characterize ambler classes A, B, and D β-lactamases, ISAba1 and integrons, biofilm formation was also investigated. Clonal relatedness was analyzed using Pulsed-Field Gel Electrophoresis (PFGE).<br><br>Results: Among 163 A. baumannii strains collected, 94.5% of them were Carbapenem-Non-Susceptible A. baumannii (CNSAB) and also 90.1 and 52.2% of them were Metallo-β-Lactamases (MBL) and Extended-Spectrum β-Lactamases (ESBL) producing isolates, respectively. Colistin and polymyxin B exhibited excellent activity against CNSAB strains. High prevalence of blaOXA - 23-like (85.1%), blaVIM (60.5%), blaPER - 1 (42.3%), tetB (67.8%), and Class 1 integrons (65.6%) were identified in CNSAB strains. ISAba1 element was associated with 42 (25.8%) and 129 (98.5%) of blaOXA-51-like and blaOXA-23-like genes, respectively. 6 clusters with the ability to form strong biofilms were found to be dominant and endemic in our entire areas.<br><br>Conclusions: Results of the present study show that antimicrobial resistance in CNSAB isolates from burn wound infections in monitored hospitals in Iran is multifactorial, and also findings of the study suggested that local antibiotic prescription policies should be regularly reviewed, and efficient infection control measures should be observed. Therefore, further strengthening of surveillance of antimicrobial resistance is urgently needed in these regions.},
}
@article {pmid31719559,
year = {2019},
author = {Horváth, B and Balázs, VL and Varga, A and Böszörményi, A and Kocsis, B and Horváth, G and Széchenyi, A},
title = {Preparation, characterisation and microbiological examination of Pickering nano-emulsions containing essential oils, and their effect on Streptococcus mutans biofilm treatment.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {16611},
pmid = {31719559},
issn = {2045-2322},
abstract = {Essential oils (EOs) are commonly applied in mouth care products like mouthwashes, mostly as an ethanolic solution or by usage of surfactants as solubilising agents. In this study, we present a formulation for preparation of Pickering nano-emulsions (PnE) of EOs as a novel form for application of EOs in mouth care. For the preparation of PnE, we have synthesised surface-modified silica nanoparticles with a mean diameter of 20 nm, as well as we have examined the effect of EOs concentration on PnE droplet size and stability. In vitro study of their effect on the Streptococcus mutans biofilm as the main pathogen of dental health problems has been performed. We have found that EOs in the PnE form has the highest effectiveness against biofilm formation. Diffusion through the biofilm model membrane was studied to explain this observation. We have found that PnEs have a better performance in the transportation of EOs trough model membrane than the ethanolic solutions and conventional emulsions (CEs).},
}
@article {pmid31719234,
year = {2019},
author = {Vaishampayan, A and Grohmann, E},
title = {Multi-resistant biofilm-forming pathogens on the International Space Station.},
journal = {Journal of biosciences},
volume = {44},
number = {5},
pages = {},
pmid = {31719234},
issn = {0973-7138},
abstract = {The International Space Station (ISS) is a confined and closed habitat with unique conditions such as cosmic radiation, and microgravity. These conditions have a strong effect on the human and spacecraft microflora. They can affect the immune response of the crew-members, thus posing a threat to their health. Microbial diversity and abundance of microorganisms from surfaces, air filters and air samples on the ISS have been studied. Enterobacteriaceae, Bacillus spp., Propionibacterium spp., Corynebacterium spp., and Staphylococcus spp. were among the most frequently isolated bacteria. Microbial growth, biofilm formation, stress response, and pathogenicity are affected by microgravity. Increased resistance to antibiotics in bacteria isolated from the ISS has often been reported. Enterococcus faecalis and Staphylococcus spp. isolates from the ISS have been shown to harbor plasmid-encoded transfer genes. These genes facilitate the dissemination of antibiotic resistances. These features of ISS-pathogens call for novel approaches including highly effective antimicrobials which can be easily used on the ISS. A promising material is the antimicrobial surface coating AGXX, a self-recycling material consisting of two noble metals. It drastically reduced microbial growth of multi-resistant human pathogens, such as staphylococci and enterococci. Further novel approaches include the application of cold atmospheric plasma for the sterilization of spacecrafts.},
}
@article {pmid31719231,
year = {2019},
author = {Manobala, T and Shukla, SK and Rao, TS and Kumar, MD},
title = {A new uranium bioremediation approach using radio-tolerant Deinococcus radiodurans biofilm.},
journal = {Journal of biosciences},
volume = {44},
number = {5},
pages = {},
pmid = {31719231},
issn = {0973-7138},
abstract = {Deinococcus radiodurans is the most radiation-tolerant organism ever known. It has gained importance in recent years as a potential candidate for bioremediation of heavy metals, especially the radioactive type. This study investigates the efficiency of a recombinant D. radiodurans (DR1-bf+) strain with an ability to form biofilm for uranium remediation. The modified Arsenazo III dye method was used to estimate the uranium concentration. Uranyl nitrate aqueous solution was generated during the operation of nuclear fuel reprocessing. The D. radiodurans biofilm (DR1-bf+) grown in the presence of 20 mM Ca2+ showed remarkable ability of uranyl ion removal. DR1-bf+ (Ca2+) biofilm removed ~75+/-2% of 1000 mg/L uranium within 30 min post-treatment from uranyl nitrate aqueous solution. Uranium removal rate was also found to be directly proportional to biofilm age. This study discusses the ability of D. radiodurans biofilm in uranium removal.},
}
@article {pmid31719217,
year = {2019},
author = {Karley, D and Shukla, SK and Rao, TS},
title = {Microbiota of spent nuclear fuel pool water with emphasis on their biofilm forming ability on stainless steel (SS-304L).},
journal = {Journal of biosciences},
volume = {44},
number = {5},
pages = {},
pmid = {31719217},
issn = {0973-7138},
abstract = {Spent nuclear fuel (SNF) pool is an essential unit of a nuclear power plant infrastructure, where radioactive fuel rods are kept for cooling and shielding, before reprocessing. This study explored the presence of bacteria in SNF pool water with emphasis on their capability to form biofilms on pool wall cladding material stainless steel (SS-304L). Bacteria were isolated from SNF pool water and were characterized using 16S rRNA gene sequencing. The six bacterial isolates (Bacillus subtilis, Staphylococcus sps., S. arlettae, S. epidermidis, S. auricularis and Chryseobacterium gleum) can grow and form biofilms at very low nutrient condition as well as in chronic radioactivity. The bacterial isolates formed biofilm on SS-304L and glass. However, the biofilm parameters assessed by CLSM microscopy showed that the strains preferred SS-304L surface for biofilm formation. On SS-304L, the maximum biomass (0.45 l μm3/l μm2) was formed by S. arlettae when compared to maximum biomass (0.054 l μm3/l μm2) by Staphylococcus sp., on glass. Maximum biofilm thickness on SS- 304L was observed by Staphylococcus sp. (8.81 l μm) when compared to that of S. epidermidis (4.16 l μm) on the glass surface. The biofilm formation on SS-304L surface suggests the possible risk of microbial-induced corrosion of SNF pool cladding material. This study highlights the need for mandatory monitoring of microbial biofilm formation in an extreme environment such as SNF pool.},
}
@article {pmid31718302,
year = {2019},
author = {Padmavathi, AR and Sriyutha Murthy, P and Das, A and Nishad, PA and Pandian, R and Rao, TS},
title = {Copper oxide nanoparticles as an effective anti-biofilm agent against a copper tolerant marine bacterium, Staphylococcus lentus.},
journal = {Biofouling},
volume = {35},
number = {9},
pages = {1007-1025},
doi = {10.1080/08927014.2019.1687689},
pmid = {31718302},
issn = {1029-2454},
abstract = {Biofilm formation on antifouling coatings is a serious concern in seawater cooling systems and the maritime industry. A prolific biofilm forming strain (Staphylococcus lentus), possessing high tolerance (>1,000 µg ml-1) to dissolved copper ions (Cu++) was isolated from titanium coupons exposed in the coastal waters of Kalpakkam, east coast of India. S. lentus formed increased biofilm (p < 0.05) at 100 µg ml-1 of Cu++ ions, when compared with the untreated control. To combat biofilm formation of this strain, the efficacy of copper oxide nanoparticles synthesized from copper nitrate by varying the concentrations of hexamine and cetyl trimethyl ammonium bromide (CTAB), was investigated. Complete (100%) inhibition of biofilm formation was observed with plain CuO NP (0.5 M hexamine, uncapped) at 1,000 µg ml-1. Capping with CTAB, influenced the morphology and the purity of the synthesized CuO NPs but did not alter their surface charge. Capping reduced metal ion release from CuO NPs and their antibacterial and anti-biofilm property against S. lentus. Overall, uncapped CuO NPs were effective in controlling biofilm formation of S. lentus. Concurrent release of copper ions and contact mediated physical damage by CuO NPs offer a promising approach to tackle metal tolerant biofilm bacteria.},
}
@article {pmid31717821,
year = {2019},
author = {Najarzadeh, Z and Mohammad-Beigi, H and Nedergaard Pedersen, J and Christiansen, G and Sønderby, TV and Shojaosadati, SA and Morshedi, D and Strømgaard, K and Meisl, G and Sutherland, D and Skov Pedersen, J and Otzen, DE},
title = {Plant Polyphenols Inhibit Functional Amyloid and Biofilm Formation in Pseudomonas Strains by Directing Monomers to Off-Pathway Oligomers.},
journal = {Biomolecules},
volume = {9},
number = {11},
pages = {},
pmid = {31717821},
issn = {2218-273X},
support = {8021-00208B//Natur og Univers, Det Frie Forskningsråd/ ; 6111-00241B//Teknologi og Produktion, Det Frie Forskningsråd/ ; IG-30702//Tarbiat Modares University/ ; },
abstract = {Self-assembly of proteins to β-sheet rich amyloid fibrils is commonly observed in various neurodegenerative diseases. However, amyloid also occurs in the extracellular matrix of bacterial biofilm, which protects bacteria from environmental stress and antibiotics. Many Pseudomonas strains produce functional amyloid where the main component is the highly fibrillation-prone protein FapC. FapC fibrillation may be inhibited by small molecules such as plant polyphenols, which are already known to inhibit formation of pathogenic amyloid, but the mechanism and biological impact of inhibition is unclear. Here, we elucidate how polyphenols modify the self-assembly of functional amyloid, with particular focus on epigallocatechin gallate (EGCG), penta-O-galloyl-β-d-glucose (PGG), baicalein, oleuropein, and procyanidin B2. We find EGCG and PGG to be the best inhibitors. These compounds inhibit amyloid formation by redirecting the aggregation of FapC monomers into oligomeric species, which according to small-angle X-ray scattering (SAXS) measurements organize into core-shell complexes of short axis diameters 25-26 nm consisting of ~7 monomers. Using peptide arrays, we identify EGCG-binding sites in FapC's linker regions, C and N-terminal parts, and high amyloidogenic sequences located in the R2 and R3 repeats. We correlate our biophysical observations to biological impact by demonstrating that the extent of amyloid inhibition by the different inhibitors correlated with their ability to reduce biofilm, highlighting the potential of anti-amyloid polyphenols as therapeutic agents against biofilm infections.},
}
@article {pmid31717723,
year = {2019},
author = {Janka, E and Carvajal, D and Wang, S and Bakke, R and Dinamarca, C},
title = {Treatment of Metformin-Containing Wastewater by a Hybrid Vertical Anaerobic Biofilm-Reactor (HyVAB).},
journal = {International journal of environmental research and public health},
volume = {16},
number = {21},
pages = {},
pmid = {31717723},
issn = {1660-4601},
abstract = {Several series of batch and continuous experiments were performed to investigate the removal of metformin and other contaminants from two wastewaters: wastewater I (WWI) containing 4 mg/L metformin and wastewater II (WWII) containing 110 g/L butanol. Biomethane potential (BMP) tests on WWII showed 77% of total chemical oxygen demand (tCOD = 110 g/L) degradability, and no apparent inhibition effects were observed. BMP tests on WWI showed an apparent inhibitory effect reflected in lower biogas production with increasing metformin concentration in the wastewater. Continuous flow hybrid vertical anaerobic biofilm (HyVAB®) experiments were consistent with the batch test findings. It was necessary to co-digest WWI (metformin) with WWII (easily degradable organics) to achieve complete metformin removal. After a period of adaptation, WWI and WWII co-digestion achieved up to 98% tCOD removal and 100% metformin removal. Most of the contaminants were removed in the anaerobic section of the HyVAB®, which implies that higher chemical oxygen demand (COD) loads than tested here are possible, given some optimization. The pilot reactor was able to manage organic loads of 11 g COD/d and above 10 mg/L metformin with a removal of 98% and 100% for tCOD and metformin, respectively.},
}
@article {pmid31715659,
year = {2019},
author = {Huang, Z and Wu, L and Li, X and Ma, L and Borriss, R and Gao, X},
title = {Zn(II) suppresses biofilm formation in Bacillus amyloliquefaciens by inactivation of the Mn(II) uptake.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.14859},
pmid = {31715659},
issn = {1462-2920},
support = {2017YFD0200400//the National Key Research and Development Program of China/ ; 2016M601834//the China Postdoctoral Science Foundation/ ; 2018T110512//the China Postdoctoral Science Foundation/ ; 31701833//the National Natural Science Foundation of China/ ; BK20170712//the Natural Science Foundation of Jiangsu Province/ ; KJQN201811//the Special Fund for the Fundamental Research Funds for the Central Universities/ ; },
abstract = {Biofilms are architecturally complex communities of microbial cells held together by a self-produced extracellular matrix. Considerable research has focused on the environmental signals that trigger or inhibit biofilm formation by affecting cellular signalling pathways; however, response to soil cues in plant-associated Bacillus has remained largely unaddressed. Therefore, we aimed to investigate the effect of Zn(II) ions in biofilm formation of Bacillus amyloliquefaciens FZB42. We demonstrated that the biofilm formation of B. amyloliquefaciens FZB42 was abolished by Zn(II) at non-deleterious concentrations. Moreover, Zn(II) blocked matrix exopolysaccharide and TasA accumulations. Furthermore, the presence of Zn(II) suppressed expression of the response regulator Spo0F but not of sensor histidine kinases KinA-D. Suppression of phosphorelay by excess Zn interferes with sinI induction under biofilm-inducing conditions, leading to repression of transcription of operons epsA-O and tapA-sigW-tasA. Addition of Zn(II) decreased the intracellular Mn(II) level by competing for binding to the solute-binding protein MntA during Mn(II) uptake. These results suggest that the metal ion Zn(II) has a negative effect on biofilm formation in the plant growth promoting and biocontrol bacterium B. amyloliquefaciens FZB42.},
}
@article {pmid31715042,
year = {2019},
author = {Peng, J and Kumar, K and Gross, M and Kunetz, T and Wen, Z},
title = {Removal of total dissolved solids from wastewater using a revolving algal biofilm reactor.},
journal = {Water environment research : a research publication of the Water Environment Federation},
volume = {},
number = {},
pages = {},
doi = {10.1002/wer.1273},
pmid = {31715042},
issn = {1554-7531},
support = {14-062-AP//Metropolitan Water Reclamation District of Greater Chicago/ ; },
abstract = {Total dissolved solids (TDS) comprising inorganic salts and organic matters are pollutants of concern to aquatic systems and water for human use. This work aimed to investigate the use of revolving algal biofilm (RAB) reactors as a sustainable and environmental friendly method to remove TDS from industrial effluents and municipal wastewaters. The wastewaters contained chloride, sodium, potassium, calcium, magnesium, and sulfate as the major components. The RAB reactors fed with synthetic industrial effluent with high TDS level demonstrated the best algal growth, with the highest TDS removal efficiency (27%) and removal rate (2,783 mg/L-day and 19,530 mg/m2 -day). A suspended algal culture system only removed 3% TDS from the same wastewater. The TDS removal by the RAB reactors was considered due to several mechanisms such as absorption by the algae cells, adsorption by extracellular polymeric substance of the biofilm, and/or precipitation. Collectively, this research shows that the RAB reactors can serve as an efficient system in wastewater remediation for TDS removal. PRACTITIONER POINTS: Total dissolved solids (TDS) in wastewater are pollutants of concern. The RAB reactors can remove TDS from various types of wastewater. The RAB reactors removed TDS by adsorbing ions elements such as Cl, Na, K, Ca, Mg, and S. The algal biomass absorbs ions through extracellular polymeric substance.},
}
@article {pmid31713778,
year = {2019},
author = {Vaknin, M and Steinberg, D and Featherstone, JD and Feuerstein, O},
title = {Exposure of Streptococcus mutans and Streptococcus sanguinis to blue light in an oral biofilm model.},
journal = {Lasers in medical science},
volume = {},
number = {},
pages = {},
doi = {10.1007/s10103-019-02903-4},
pmid = {31713778},
issn = {1435-604X},
support = {2013445//United States-Israel Binational Science Foundation/ ; 2013445//United States - Israel Binational Science Foundation/ ; },
abstract = {The potential anti-cariogenic effect of blue light was evaluated using an oral biofilm model. Two species, Streptococcus mutans and Streptococcus sanguinis, were cultivated ex vivo on bovine enamel blocks for 24 h, either separately or mixed together, then exposed to blue light (wavelengths 400-500 nm) using 112 J/cm2. Twenty four or 48 h after exposure to light the biofilm structure and biomass were characterized and quantified using SEM and qPCR, respectively. Bacterial viability was analyzed by CLSM using live/dead bacterial staining. Gene expression was examined by RT-qPCR. After exposure to light, S. mutans biomass in mono-species biofilm was increased mainly by dead bacteria, relative to control. However, the bacterial biomass of S. mutans when grown in mixed biofilm and of S. sanguinis in mono-species biofilm was reduced after light exposure, with no significant change in viability when compared to control. Furthermore, when grown separately, an upregulation of gene expression related to biofilm formation of S. mutans, and downregulation of similar genes of S. sanguinis, were measured 24 h after exposure to blue light. However, in mixed biofilm, a downregulation of those genes in both species was observed, although not significant in S. mutans. In conclusion, blue light seems to effectively alter the bacterial biomass by reducing the viability and virulence characteristics in both bacterial species and may promote the anti-cariogenic balance between them, when grown in a mixed biofilm. Therefore, exposure of oral biofilm to blue light has the potential to serve as a complementary approach in preventive dentistry.},
}
@article {pmid31713454,
year = {2019},
author = {Rollin-Pinheiro, R and Rochetti, VP and Xisto, MIDDS and Liporagi-Lopes, LC and Bastos, B and Rella, A and Singh, A and Rozental, S and Del Poeta, M and Barreto-Bergter, E},
title = {Sphingolipid biosynthetic pathway is crucial for growth, biofilm formation and membrane integrity of Scedosporium boydii.},
journal = {Future medicinal chemistry},
volume = {11},
number = {22},
pages = {2905-2917},
doi = {10.4155/fmc-2019-0186},
pmid = {31713454},
issn = {1756-8927},
abstract = {Aim: Glycosphingolipids are conserved lipids displaying a variety of functions in fungal cells, such as determination of cell polarity and virulence. They have been considered as potent targets for new antifungal drugs. The present work aimed to test two inhibitors, myriocin and DL-threo-1-Phenyl-2-palmitoylamino-3-morpholino-1-propanol, in Scedosporium boydii, a pathogenic fungus which causes a wide range of disease. Materials &amp; methods: Mass spectrometry, microscopy and cell biology approaches showed that treatment with both inhibitors led to defects in fungal growth and membrane integrity, and caused an increased susceptibility to the current antifungal agents. Conclusion: These data demonstrate the antifungal potential of drugs inhibiting sphingolipid biosynthesis, as well as the usefulness of sphingolipids as promising targets for the development of new therapeutic options.},
}
@article {pmid31712267,
year = {2019},
author = {Harro, JM and Achermann, Y and Freiberg, JA and Allison, DL and Brao, KJ and Marinos, DP and Sanjari, S and Leid, JG and Shirtliff, ME},
title = {Clearance of Staphylococcus aureus from In Vivo Models of Chronic Infection by Immunization Requires Both Planktonic and Biofilm Antigens.},
journal = {Infection and immunity},
volume = {88},
number = {1},
pages = {},
doi = {10.1128/IAI.00586-19},
pmid = {31712267},
issn = {1098-5522},
abstract = {Staphylococcus aureus is a causative agent of chronic biofilm-associated infections that are recalcitrant to resolution by the immune system or antibiotics. To combat these infections, an antistaphylococcal, biofilm-specific quadrivalent vaccine against an osteomyelitis model in rabbits has previously been developed and shown to be effective at eliminating biofilm-embedded bacterial populations. However, the addition of antibiotics was required to eradicate remaining planktonic populations. In this study, a planktonic upregulated antigen was combined with the quadrivalent vaccine to remove the need for antibiotic therapy. Immunization with this pentavalent vaccine followed by intraperitoneal challenge of BALB/c mice with S. aureus resulted in 16.7% and 91.7% mortality in pentavalent vaccine and control groups, respectively (P < 0.001). Complete bacterial elimination was found in 66.7% of the pentavalent cohort, while only 8.3% of the control animals cleared the infection (P < 0.05). Further protective efficacy was observed in immunized rabbits following intramedullary challenge with S. aureus, where 62.5% of the pentavalent cohort completely cleared the infection, versus none of the control animals (P < 0.05). Passive immunization of BALB/c mice with serum IgG against the vaccine antigens prior to intraperitoneal challenge with S. aureus prevented mortality in 100% of mice and eliminated bacteria in 33.3% of the challenged mice. These results demonstrate that targeting both the planktonic and biofilm stages with the pentavalent vaccine or the IgG elicited by immunization can effectively protect against S. aureus infection.},
}
@article {pmid31710602,
year = {2019},
author = {Bridges, AA and Bassler, BL},
title = {The intragenus and interspecies quorum-sensing autoinducers exert distinct control over Vibrio cholerae biofilm formation and dispersal.},
journal = {PLoS biology},
volume = {17},
number = {11},
pages = {e3000429},
pmid = {31710602},
issn = {1545-7885},
abstract = {Vibrio cholerae possesses multiple quorum-sensing (QS) systems that control virulence and biofilm formation among other traits. At low cell densities, when QS autoinducers are absent, V. cholerae forms biofilms. At high cell densities, when autoinducers have accumulated, biofilm formation is repressed, and dispersal occurs. Here, we focus on the roles of two well-characterized QS autoinducers that function in parallel. One autoinducer, called cholerae autoinducer-1 (CAI-1), is used to measure Vibrio abundance, and the other autoinducer, called autoinducer-2 (AI-2), is widely produced by different bacterial species and presumed to enable V. cholerae to assess the total bacterial cell density of the vicinal community. The two V. cholerae autoinducers funnel information into a shared signal relay pathway. This feature of the QS system architecture has made it difficult to understand how specific information can be extracted from each autoinducer, how the autoinducers might drive distinct output behaviors, and, in turn, how the bacteria use QS to distinguish kin from nonkin in bacterial communities. We develop a live-cell biofilm formation and dispersal assay that allows examination of the individual and combined roles of the two autoinducers in controlling V. cholerae behavior. We show that the QS system works as a coincidence detector in which both autoinducers must be present simultaneously for repression of biofilm formation to occur. Within that context, the CAI-1 QS pathway is activated when only a few V. cholerae cells are present, whereas the AI-2 pathway is activated only at much higher cell density. The consequence of this asymmetry is that exogenous sources of AI-2, but not CAI-1, contribute to satisfying the coincidence detector to repress biofilm formation and promote dispersal. We propose that V. cholerae uses CAI-1 to verify that some of its kin are present before committing to the high-cell-density QS mode, but it is, in fact, the broadly made autoinducer AI-2 that sets the pace of the V. cholerae QS program. This first report of unique roles for the different V. cholerae autoinducers suggests that detection of kin fosters a distinct outcome from detection of nonkin.},
}
@article {pmid31710252,
year = {2019},
author = {Rossoni, RD and de Barros, PP and Lopes, LADC and Ribeiro, FC and Nakatsuka, T and Kasaba, H and Junqueira, JC},
title = {Effects of surface pre-reacted glass-ionomer (S-PRG) eluate on Candida spp.: antifungal activity, anti-biofilm properties, and protective effects on Galleria mellonella against C. albicans infection.},
journal = {Biofouling},
volume = {35},
number = {9},
pages = {997-1006},
doi = {10.1080/08927014.2019.1686485},
pmid = {31710252},
issn = {1029-2454},
abstract = {Surface pre-reacted glass-ionomer (S-PRG) is a bioactive filler produced by PRG technology, which is applied to various dental materials. The inhibitory effects of S-PRG eluate against Candida, the most common fungal oral pathogen, were investigated. Minimum inhibitory concentrations (MIC) and anti-biofilm activities were tested against Candida albicans, Candida glabrata, Candida krusei, and Candida tropicalis. For the in vivo study, Galleria mellonella was used as a model to evaluate the effects of S-PRG on toxicity, hemocyte counts and candidiasis. The MIC of S-PRG ranged from 5 to 40% (v/v). S-PRG eluate exhibited anti-biofilm activity for all the Candida species tested. Furthermore, injection of S-PRG eluate into G. mellonella was not toxic to the larvae and protected G. mellonella against experimental candidiasis. In addition, S-PRG eluate inhibited biofilm formation by C. albicans, C. glabrata, C. krusei, and C. tropicalis and exerted protective effects on G. mellonella against experimental candidiasis in vivo.},
}
@article {pmid31709555,
year = {2020},
author = {Lange, MD and Farmer, BD and Abernathy, J},
title = {Vertebrate mucus stimulates biofilm development and upregulates iron acquisition genes in Flavobacterium columnare.},
journal = {Journal of fish diseases},
volume = {43},
number = {1},
pages = {101-110},
doi = {10.1111/jfd.13103},
pmid = {31709555},
issn = {1365-2761},
support = {6010-32000-026-00-D//USDA-ARS Research Project/ ; 6028-32000-007-00-D//USDA-ARS Research Project/ ; },
abstract = {Columnaris disease is responsible for substantial losses throughout the production of many freshwater fish species. One of the ways in which the bacterium Flavobacterium columnare is so effective in initiating disease is through the formation of biofilms on fish skin and gills. To further explore the interaction between host factors and bacterial cells, we assayed the ability of vertebrate mucus to enhance F. columnare biofilm development. Different concentrations of catfish, tilapia and pig mucus (5-60 µg/ml) increased biofilm growth at varying degrees among F. columnare isolates. Our data suggest that vertebrate mucus acts as a signalling molecule for the development of F. columnare biofilms; however, there are clear disparities in how individual isolates respond to different mucus fractions to stimulate biofilms. The expression of iron acquisition genes among two genomovar II isolates showed that ferroxidase, TonB receptor and the siderophore synthetase gene were all significantly upregulated among F. columnare biofilms. Interestingly, the siderophore acetyltransferase gene was only shown to be significantly upregulated in one of the genomovar II isolates. This work provides insight into our understanding of the interaction between F. columnare and vertebrate mucus, which likely contributes to the growth of planktonic cells and the transition into biofilms.},
}
@article {pmid31709419,
year = {2019},
author = {Wang, Z and Chen, XM and Ni, BJ and Tang, YN and Zhao, HP},
title = {Model-based assessment of chromate reduction and nitrate effect in a methane-based membrane biofilm reactor.},
journal = {Water research X},
volume = {5},
number = {},
pages = {100037},
pmid = {31709419},
issn = {2589-9147},
abstract = {Chromate contamination can pose a high risk to both the environment and public health. Previous studies have shown that CH4-based membrane biofilm reactor (MBfR) is a promising method for chromate removal. In this study, we developed a multispecies biofilm model to study chromate reduction and its interaction with nitrate reduction in a CH4-based MBfR. The model-simulated results were consistent with the experimental data reported in the literature. The model showed that the presence of nitrate in the influent promoted the growth of heterotrophs, while suppressing methanotrophs and chromate reducers. Moreover, it indicated that a biofilm thickness of 150 μm and an influent dissolved oxygen concentration of 0.5 mg O2/L could improve the reactor performance by increasing the chromate removal efficiency under the simulated conditions.},
}
@article {pmid31708908,
year = {2019},
author = {She, P and Zhou, L and Li, S and Liu, Y and Xu, L and Chen, L and Luo, Z and Wu, Y},
title = {Synergistic Microbicidal Effect of Auranofin and Antibiotics Against Planktonic and Biofilm-Encased S. aureus and E. faecalis.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2453},
pmid = {31708908},
issn = {1664-302X},
abstract = {Methicillin-resistant/susceptible Staphylococcus aureus (MRSA/MSSA) and Enterococcus faecalis strains are often found in community- and hospital-acquired infections. The single use of conventional antibiotics hardly completely kills the bacterial cells of interest, especially in the form of biofilms. Thus, drug repurposing and antimicrobial combination are promising ways to solve this problem. Antimicrobial susceptibility assays against cocci in a suspension and in a biofilm mode of growth were performed with broth microdilution methods. Checkerboard assays and the cutaneous mouse infection model were used to examine the activity of auranofin and conventional antibiotics alone and in combination. In the present study, auranofin possesses potent antimicrobial activities against both planktonic cells and biofilms with minimum inhibitory concentrations ranging 0.125-0.5 mg/L. Auranofin in combination with linezolid or fosfomycin showed synergistic antimicrobial activities against S. aureus MSSA and MRSA both in vitro and in vivo. Similarly, auranofin also behaved synergistic effect with chloramphenicol against E. faecalis. Additionally, auranofin improved the antibiofilm efficacy of chloramphenicol and linezolid, even on the biofilms grown on a catheter surface. Though, S. epidermidis showed significant susceptibility to AF treatment, no synergistic antimicrobial effects were observed with antibiotics we tested. In all, the use of a combination of auranofin with linezolid, fosfomycin, and chloramphenicol can provide a synergistic microbicidal effect in vitro and in vivo, which rapidly enhances antimicrobial activity and may help prevent or delay the emergence of resistance.},
}
@article {pmid31708905,
year = {2019},
author = {Millen, S and Gross, C and Donhauser, N and Mann, MC and Péloponèse, JM and Thoma-Kress, AK},
title = {Collagen IV (COL4A1, COL4A2), a Component of the Viral Biofilm, Is Induced by the HTLV-1 Oncoprotein Tax and Impacts Virus Transmission.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2439},
pmid = {31708905},
issn = {1664-302X},
abstract = {Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent for Adult T-Cell Leukemia/Lymphoma (ATLL) and HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP). HTLV-1 infects CD4+ T-cells via cell-to-cell transmission requiring reorganization of the cytoskeleton and expression of the viral transactivator and oncoprotein Tax. Viruses spread at the virological synapse (VS), a virus-induced specialized cell-cell contact, by polarized budding into synaptic clefts, and by cell surface transfer of viral biofilms (VBs). Since little is known about Tax's role in formation of the VB, we asked which component of the VB is regulated by Tax and important for HTLV-1 transmission. Collagens are not only structural proteins of the extracellular matrix and basal membrane but also represent an important component of the VB. Here, we report that among the collagens known to be present in VBs, COL4 is specifically upregulated in the presence of HTLV-1 infection. Further, we found that transient expression of Tax is sufficient to induce COL4A1 and COL4A2 transcripts in Jurkat and CCRF-CEM T-cells, while robust induction of COL4 protein requires continuous Tax expression as shown in Tax-transformed T-cell lines. Repression of Tax led to a significant reduction of COL4A1/A2 transcripts and COL4 protein. Mechanistically, luciferase-based promoter studies indicate that Tax activates the COL4A2 and, to a less extent, the COL4A1 promoter. Imaging showing partial co-localization of COL4 with the viral Gag protein in VBs at the VS and transfer of COL4 and Gag to target cells suggests a role of COL4 in VB formation. Strikingly, in chronically infected C91-PL cells, knockout of COL4A2 impaired Gag transfer between infected T-cells and acceptor T-cells, while release of virus-like particles was unaffected. Taken together, we identified COL4 (COL4A1, COL4A2) as a component of the VB and a novel cellular target of Tax with COL4A2 appearing to impact virus transmission. Thus, this study is the first to provide a link between Tax's activity and VB formation by hijacking COL4 protein functions.},
}
@article {pmid31706910,
year = {2019},
author = {Das, P and Karankar, VS},
title = {New avenues of controlling microbial infections through anti-microbial and anti-biofilm potentials of green mono-and multi-metallic nanoparticles: A review.},
journal = {Journal of microbiological methods},
volume = {167},
number = {},
pages = {105766},
doi = {10.1016/j.mimet.2019.105766},
pmid = {31706910},
issn = {1872-8359},
abstract = {Nanoparticles synthesized through the green route deserve special mention because this green technology is not only energy-efficient and cost-effective but also amenable to the environment. Various biological resources have been used for the generation of these 'green nanoparticles'. Biological wastes have also been focused in this direction thereby promoting the value of waste. Reports indicate that green nanoparticles exhibit remarkable antimicrobial activitiesboth singly as well as in combination with standard antibiotics. The current phenomenon of multi-drug resistance has resulted due to indiscriminate administration of high-doses of antibiotics followed by significant toxicity. In the face of this emergence of drug-resistant microbesthe efficacy of green nanoparticles might prove greatly beneficial. Microbial biofilm is another hurdle in the effective treatment of diseases as the microorganismsbeing embedded in the meshwork of the biofilmevade the antimicrobial agents. Nanoparticles may act as a ray of hope on the face of this challenge tooas they not only destroy the biofilms but also lessen the doses of antibiotics requiredwhen administered in combination with the nanoparticles. It should be further noted that the resistance mechanisms exhibited by the microorganisms seem not that relevant for nanoparticles. The current review, to the best of our knowledgefocuses on the structures of these green nanoparticles along with their biomedical potentials. It is interesting to note how a variety of structures are generated by using resources like microbes or plants or plant products and how the structure affects their activities. This study might pave the way for further development in this arena and future work may be taken up in identifying the detailed mechanism by which 'green' synthesis empowers nanoparticles to kill pathogenic microbes.},
}
@article {pmid31706760,
year = {2020},
author = {Lawrence, JR and Paule, A and Swerhone, GDW and Roy, J and Grigoryan, AA and Dynes, JJ and Chekabab, SM and Korber, DR},
title = {Microscale and molecular analyses of river biofilm communities treated with microgram levels of cerium oxide nanoparticles indicate limited but significant effects.},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {256},
number = {},
pages = {113515},
doi = {10.1016/j.envpol.2019.113515},
pmid = {31706760},
issn = {1873-6424},
abstract = {Cerium oxide (CeO2) nanoparticles are used as in-fuel catalysts and in manufacturing processes, creating a potential for release to aquatic environments. Exposures at 1 and 10 μg/L CeO2-nanoparticles were made to assess effects during the development of river biofilm communities. Scanning transmission x-ray microscopy (STXM) indicated extensive sorption of nanoparticles to the community and co-localization with lipid moieties. Following 8 weeks of development, polycarbonate coupons were removed from the reactors and used for molecular analyses, denaturing gradient gel electrophoresis analysis (DGGE-16S rRNA) and 16S rRNA amplicon sequencing. Microscopic imaging of the biofilm communities (bacterial, photosynthetic biomass, exopolymer composition, thickness, protozoan numbers), as well as carbon substrate utilization fingerprinting was performed. There was a trend toward reduced photosynthetic biomass, but no significant effects of CeO2 exposure were found on photosynthetic and bacterial biomass or biofilm thickness. Sole carbon source utilization analyses indicated increased utilization of 10 carbon sources in the carbohydrate, carboxylic acid and amino acids categories related to CeO2 exposures; however, predominantly, no significant effects (p < 0.05) were detected. Measures of microbial diversity, lectin binding affinities of exopolymeric substances and results of DGGE analyses, indicated significant changes to community composition (p < 0.05) with CeO2 exposure. Increased binding of the lectin Canavalia ensiformis was observed, consistent with changes in bacterial-associated polymers. Whereas, no significant changes were observed in binding to residues associated with algal and cyanobacterial exopolymers. 16S rRNA amplicon sequencing of community DNA indicated changes in diversity and shifts in community composition; however, these did not trend with increasing CeO2 exposure. Counting of protozoans in the biofilm communities indicated no significant effects on this trophic level. Thus, based on biomass and functional measures, CeO2 nanoparticles did not appear to have significant effects; however, there was evidence of selection pressure resulting in significant changes in microbial community composition.},
}
@article {pmid31706043,
year = {2019},
author = {Keren-Paz, A and Kolodkin-Gal, I},
title = {A brick in the wall: Discovering a novel mineral component of the biofilm extracellular matrix.},
journal = {New biotechnology},
volume = {56},
number = {},
pages = {9-15},
doi = {10.1016/j.nbt.2019.11.002},
pmid = {31706043},
issn = {1876-4347},
abstract = {Multicellular bacterial communities, known as biofilms, have been thought to be held together solely by a self-produced organic extracellular matrix (ECM). However, new evidence for a missed mineral constituent of ECM in both Gram-positive and Gram-negative bacterial species, is accumulating. Study of two phylogenetically distinct bacteria, Bacillus subtilis and Mycobacterium smegmatis, identified a novel mechanism crucial for proper biofilm development and architecture - an active, genetically regulated, production of crystalline calcite. The calcite scaffolds stabilize bacterial biofilms, limit penetration of small molecule solutes such as antibiotics and play a conserved role in the assembly of those complex differentiated multicellular communities. This review discusses the recently discovered structural and functional roles of extracellular minerals in biofilms. It is proposed that it is time for a more complete view of the ECM as a complex combination of organic and nonorganic materials, especially in the light of the possible implications for treatment of biofilm infections.},
}
@article {pmid31705932,
year = {2020},
author = {Sood, U and Singh, DN and Hira, P and Lee, JK and Kalia, VC and Lal, R and Shakarad, M},
title = {Rapid and solitary production of mono-rhamnolipid biosurfactant and biofilm inhibiting pyocyanin by a taxonomic outlier Pseudomonas aeruginosa strain CR1.},
journal = {Journal of biotechnology},
volume = {307},
number = {},
pages = {98-106},
doi = {10.1016/j.jbiotec.2019.11.004},
pmid = {31705932},
issn = {1873-4863},
abstract = {Biosurfactant - Rhamnolipids (RLs) and antibacterial toxin - pyocyanin (PYO) produced by Pseudomonas aeruginosa strains have great potential for biotechnological applications. Generally, RLs are produced as a mixture of di-rhamnolipids (di-RLs) and mono-rhamnolipids (mono-RLs). Mono-RLs possess superior emulsification and antimicrobial properties and are costlier than di-RLs. In this study, a taxonomic outlier P. aeruginosa strain CR1 isolated from rhizosphere soil was explored for mono-RLs and PYO production. Phylogenetically strain CR1 resembles avirulent outlier P. aeruginosa strain ATCC9027, lacks archetypical virulence genes and harbors unique pathways for the synthesis of solely mono-RLs and PYO. Strain CR1 produced RL biosurfactant which efficiently emulsified hydrocarbons, showed hemolysis and inhibited Bacillus subtilis. At 37 °C, strain CR1 exclusively produced 21.77 g L-1 and 19.22 g L-1 rhamnolipid in glycerol amended Luria Bertani (LB) medium and basal medium amended with rice bran oil, respectively after 54 h growth. Besides RL production was unaffected under varying nitrogen sources. Structural characterization using FTIR, TLC, and LC-MS confirmed that strain CR1 exclusively produced mono-RLs, majorly dominated by Rha-C10-C10, Rha-C10-C8, and CH3-Rha-C12:2-C10:1. The compound was stable over a wide pH range (4-12), salinity (25%) and 100 °C indicating its applicability under harsh environmental conditions. In addition, strain CR1 produced 4.5 μg mL-1 PYO, which could efficiently inhibit biofilm formation by Bacillus species. The environmental outlier strain CR1 can be used for the industrial production of biotechnologically important mono-RLs and PYO.},
}
@article {pmid31705133,
year = {2020},
author = {Marquès, C and Collin, V and Franceschi, C and Charbonnel, N and Chatellier, S and Forestier, C},
title = {Fosfomycin and Staphylococcus aureus: transcriptomic approach to assess effect on biofilm, and fate of unattached cells.},
journal = {The Journal of antibiotics},
volume = {73},
number = {2},
pages = {91-100},
doi = {10.1038/s41429-019-0256-y},
pmid = {31705133},
issn = {1881-1469},
abstract = {Interest has been rekindled in the old antibiotic fosfomycin, partly because of its ability to penetrate biofilm. Using a transcriptomic approach, we investigated the modifications induced by fosfomycin in sessile cells of a clinical Staphylococcus aureus isolated from a device-associated infection. Cells still able to form biofilm after 4 h of incubation in the presence of subinhibitory concentrations of fosfomycin and cells from 24-h-old biofilm later submitted to fosfomycin had 6.77% and 9.41%, respectively, of differentially expressed genes compared with their antibiotic-free control. Fosfomycin induced mostly downregulation of genes assigned to nucleotide, amino acid and carbohydrate transport, and metabolism. Adhesins and capsular biosynthesis proteins encoding genes were downregulated in fosfomycin-grown biofilm, whereas the murein hydrolase regulator lgrA and a D-lactate dehydrogenase-encoding gene were upregulated. In fosfomycin-treated biofilm, the expression of genes encoding adhesins, the cell wall biosynthesis protein ScdA, and to a lesser extent the fosfomycin target MurA was also decreased. Unattached cells surrounding fosfomycin-grown biofilm showed greater ability to form aggregates than their counterparts obtained without fosfomycin. Reducing their global metabolism and lowering cell wall turnover would allow some S. aureus cells to grow in biofilm despite fosfomycin stress while promoting hyperadherent phenotype in the vicinity of the fosfomycin-treated biofilm.},
}
@article {pmid31704413,
year = {2020},
author = {Rehman, ZU and Fortunato, L and Cheng, T and Leiknes, T},
title = {Metagenomic analysis of sludge and early-stage biofilm communities of a submerged membrane bioreactor.},
journal = {The Science of the total environment},
volume = {701},
number = {},
pages = {134682},
doi = {10.1016/j.scitotenv.2019.134682},
pmid = {31704413},
issn = {1879-1026},
abstract = {Biofilm formation on membranes in activated sludge membrane bioreactors (MBR), commonly identified as biofouling, is a significant problem for MBR operations. A better understanding of microbial species involved in the biofilm formation is needed to develop anti-biofilm measures. A read-based and genome-resolved shotgun metagenomic approach was applied to characterize the composition and functional potential of the sludge and early stage biofilm microbial communities in an MBR process. Read-based analysis revealed that the prevalence of different phyla are relatively similar in both the sludge and biofilm samples, with Proteobacteria as the most dominant, followed by Chloroflexi, Bacteroidetes and Planctomycetes. However, the relative abundance of these phyla slightly varies between the sludge and biofilm. Phyla such as Actinobacteria, bacterial candidate phyla, Chlamydiae, Cyanobacteria/Melainabacteria and Firmicutes are 2 to 4 times more abundant in the biofilm than in the sludge. At the genus level, genera belonging to Proteobacteria (Legionella, Caulobacter, Sphingomonas, Acinetobacter and Rhizobium), Cyanobacteria (Hassallia), and Spirochaetes (Turneriella) are at least twice more abundant in the biofilm. These genera, especially those belonging to Phylum Proteobacteria, are known to play an important role in the formation of biofilms on surfaces. The Alpha diversity is found slightly higher in the biofilm, compared with sludge samples. Functional classification of reads through the SEED subsystem shows that functional classes such as those involved in the metabolism of various molecules are significantly different in the biofilm and sludge. A phylogenomic analysis of the six extracted metagenome assembled genomes (MAGs) shows that three MAGs belong to Proteobacteria, and one MAG belong to each of Chloroflexi, Bacteroidetes and Planctomycetes. The relative abundance of the MAG belonging to Alphaproteobacteria is higher in the biofilm. A functional potential analysis of the MAGs reveals their potential to metabolize carbon and nitrogen sources, as well as the prevalence of antibiotic resistance genes.},
}
@article {pmid31703923,
year = {2019},
author = {Alfaifi, AA and Lin, WS and Aldhaian, BA and Levon, JA and Gregory, RL},
title = {Impact of caffeine on metabolic activity and biofilm formation of Candida albicans on acrylic denture resin in the presence of nicotine.},
journal = {The Journal of prosthetic dentistry},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.prosdent.2019.09.007},
pmid = {31703923},
issn = {1097-6841},
abstract = {STATEMENT OF PROBLEM: Candida albicans has been implicated in denture stomatitis, and this effect is exacerbated by nicotine exposure. However, studies have also suggested that caffeine exposure inhibits the growth of C. albicans. The interaction effects of nicotine and caffeine are not yet clear on the growth of C. albicans.<br><br>PURPOSE: The purpose of this in vitro study was to determine the effect of caffeine on metabolic activity and biofilm formation of C. albicans growing on acrylic denture resin while simultaneously exposed to nicotine and, if an effect were to be identified, whether this effect would vary depending on the caffeine concentration.<br><br>MATERIAL AND METHODS: A total of 240 acrylic resin specimens were divided into 2 equal groups (120 each). Specimens in one group were processed to measure C. albicans metabolic activity, and those in the other group were processed to measure C. albicans biofilm attachment. Ten subgroups (n=12) were established within each group with different concentration combinations of nicotine and caffeine to test the interaction effect. The first subgroup was designed as a negative control, containing 0 mg/mL of nicotine and caffeine. The following subgroups all contained 8.00 mg/mL of nicotine, and the caffeine concentrations were prepared at the following 9 levels: 0, 0.25, 0.50, 1.00, 2.00, 4.00, 8.00, 16.00, and 32.00 mg/mL. Metabolic activity was measured by using a 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-carboxanilide (XTT) assay. Biofilm attachment was measured by using spiral plating and calculated in terms of the number of colony-forming units (CFUs)/mL. Descriptive statistics and a 2-way ANOVA were conducted to determine whether the concentrations of nicotine and caffeine used affected the biofilm attachment and metabolic activity of C. albicans (α=.05).<br><br>RESULTS: The presence of 8 mg/mL of nicotine increased the metabolic activity and biofilm formation of C. albicans. When compared with the 0 mg/mL of caffeine and 8.00 mg/mL of nicotine group, caffeine from 1.00 to 4.00 mg/mL significantly increased C. albicans biofilm metabolic activity. Caffeine at 16.00 and 32.00 mg/mL significantly decreased C. albicans biofilm metabolic activity in the presence of 8 mg/mL of nicotine. Caffeine from 1.00 to 32.00 mg/mL significantly decreased the biofilm formation of C. albicans in the presence of 8 mg/mL of nicotine.<br><br>CONCLUSIONS: The presence of 8 mg/mL of nicotine alone increased the metabolic activity and biofilm formation of C. albicans. In the presence of 8 mg/mL of nicotine with different caffeine concentrations, the results suggest that, overall, caffeine at higher concentrations (16 and 32 mg/mL) inhibited the metabolic activity and biofilm formation of C. albicans on acrylic denture resin most.},
}
@article {pmid31703877,
year = {2020},
author = {Liu, F and Sun, Z and Wang, F and Liu, Y and Zhu, Y and Du, L and Wang, D and Xu, W},
title = {Inhibition of biofilm formation and exopolysaccharide synthesis of Enterococcus faecalis by phenyllactic acid.},
journal = {Food microbiology},
volume = {86},
number = {},
pages = {103344},
doi = {10.1016/j.fm.2019.103344},
pmid = {31703877},
issn = {1095-9998},
abstract = {This study aimed to evaluate the inhibitory activity of phenyllactic acid (PLA) against the biofilm formation of Enterococcus faecalis and to explore its potential molecular mechanism. The MIC value of PLA that inhibited the growth of E. faecalis R612-Z1 in BHI broth was 5 mg/mL. PLAs at subinhibitory concentrations of 1.25 and 2.50 mg/mL were found to inhibit biofilm formation by a crystal violet staining assay. The cell swimming and swarming motilities of E. faecalis were reduced in the presence of PLA. An apparent decrease in the thickness of PLA-treated biofilms was observed through confocal laser scanning microscopy analysis. The exopolysaccharide production in E. faecalis biofilms was inhibited by EPS quantification assay and scanning electron microscopy (SEM). qRT-PCR analyses showed that PLA down-regulated the transcription of Ebp pili genes (ebpABC) and Epa polysaccharide genes (epaABE). PLA inhibited the biofilm formation by interfering with cell mobility and EPS production of E. faecalis. In addition, PLA at concentrations of 10.0 mg/mL can effectively control the bacterial cells in a three-day-old mature biofilm of E. faecalis grown on 24-well flat-bottom polystyrene plates and stainless-steel surfaces. Thus, PLA is potentially an effective agent to control E. faecalis biofilms.},
}
@article {pmid31703870,
year = {2020},
author = {Guo, D and Wang, S and Li, J and Bai, F and Yang, Y and Xu, Y and Liang, S and Xia, X and Wang, X and Shi, C},
title = {The antimicrobial activity of coenzyme Q0 against planktonic and biofilm forms of Cronobacter sakazakii.},
journal = {Food microbiology},
volume = {86},
number = {},
pages = {103337},
doi = {10.1016/j.fm.2019.103337},
pmid = {31703870},
issn = {1095-9998},
abstract = {Coenzyme Q0 (CoQ0) has demonstrated antitumor, anti-inflammatory, and anti-angiogenic activities. Cronobacter sakazakii is an opportunistic foodborne pathogen associated with high mortality in neonates. In this study, the antimicrobial activity and possible antimicrobial mechanism of CoQ0 against C. sakazakii were investigated. Moreover, the inactivation effect of CoQ0 on C. sakazakii in biofilms was also evaluated. The minimum inhibitory concentration (MIC) of CoQ0 against C. sakazakii strains ranged from 0.1 to 0.2 mg/mL. Treatment caused cell membrane dysfunction, as evidenced by cell membrane hyperpolarization, decreased intracellular ATP concentration and cell membrane integrity, and changes in cellular morphology. CoQ0 combined with mild heat treatment (45, 50, or 55 °C) decreased the number of viable non-desiccated and desiccated C. sakazakii cells in a time- and dose-dependent manner in reconstituted infant milk. Furthermore, CoQ0 showed effective inactivation activity against C. sakazakii in biofilms on stainless steel, reducing the number of viable cells and damaging the structure of the biofilm. These findings suggest that CoQ0 has a strong inactivate effect on C. sakazakii and could be used in food production environments to effectively control C. sakazakii and reduce the number of illnesses associated with it.},
}
@article {pmid31703863,
year = {2020},
author = {Li, T and Sun, X and Chen, H and He, B and Mei, Y and Wang, D and Li, J},
title = {Methyl anthranilate: A novel quorum sensing inhibitor and anti-biofilm agent against Aeromonas sobria.},
journal = {Food microbiology},
volume = {86},
number = {},
pages = {103356},
doi = {10.1016/j.fm.2019.103356},
pmid = {31703863},
issn = {1095-9998},
abstract = {Quorum sensing (QS), bacterial cell-to-cell communication, is a gene regulatory mechanism that regulates virulence potential and biofilm formation in many pathogens. Aeromonas sobria, a common aquaculture pathogen, was isolated and identified by our laboratory from the deteriorated turbot, and its potential for virulence factors and biofilm production was regulated by QS system. In view of the interference with QS system, this study was aimed to investigate the effect of methyl anthranilate at sub-Minimum Inhibitory Concentrations (sub-MICs) on QS-regulated phenotypes in A. sobria. The results suggested that 0.5 μL/mL of methyl anthranilate evidently reduced biofilm formation (51.44%), swinging motility (74.86%), swarming motility (71.63%), protease activity (43.08%), and acyl-homoserine lactone (AHL) production. Furthermore, the real-time quantitative PCR (RT-qPCR) and in silico analysis showed that methyl anthranilate might inhibit QS system in A. sobria by interfering with the biosynthesis of AHL, as well as competitively binding with receptor protein. Therefore, our data indicated the feasibility of methyl anthranilate as a promising QS inhibitor and anti-biofilm agent for improving food safety.},
}
@article {pmid31700653,
year = {2019},
author = {Harrison, A and Hardison, RL and Wallace, RM and Fitch, J and Heimlich, DR and Bryan, MO and Dubois, L and John-Williams, LS and Sebra, RP and White, P and Moseley, MA and Thompson, JW and Justice, SS and Mason, KM},
title = {Reprioritization of biofilm metabolism is associated with nutrient adaptation and long-term survival of Haemophilus influenzae.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {33},
pmid = {31700653},
issn = {2055-5008},
support = {R01 DC013313/DC/NIDCD NIH HHS/United States ; },
abstract = {Nontypeable Haemophilus influenzae (NTHI) is a human-restricted pathogen with an essential requirement for heme-iron acquisition. We previously demonstrated that microevolution of NTHI promotes stationary phase survival in response to transient heme-iron restriction. In this study, we examine the metabolic contributions to biofilm formation using this evolved NTHI strain, RM33. Quantitative analyses identified 29 proteins, 55 transcripts, and 31 metabolites that significantly changed within in vitro biofilms formed by RM33. The synthesis of all enzymes within the tryptophan and glycogen pathways was significantly increased in biofilms formed by RM33 compared with the parental strain. In addition, increases were observed in metabolite transport, adhesin production, and DNA metabolism. Furthermore, we observed pyruvate as a pivotal point in the metabolic pathways associated with changes in cAMP phosphodiesterase activity during biofilm formation. Taken together, changes in central metabolism combined with increased stores of nutrients may serve to counterbalance nutrient sequestration.},
}
@article {pmid31700570,
year = {2019},
author = {Teves, A and Blanco, D and Casaretto, M and Torres, J and Alvarado, D and Jaramillo, DE},
title = {Effectiveness of different disinfection techniques of the root canal in the elimination of a multi-species biofilm.},
journal = {Journal of clinical and experimental dentistry},
volume = {11},
number = {11},
pages = {e978-e983},
pmid = {31700570},
issn = {1989-5488},
abstract = {Background: The purpose of the study was to evaluate the effectiveness of different root canal disinfection techniques in the elimination of a multi-species biofilm from inside the root canal.<br><br>Material and Methods: Fifty mandibular first premolars were used in the present study, standardized to 11mm of root length, and instrumented with a reciprocation system Reciproc, (VDW GmbH, Munich, Germany) to a #50. Longitudinally sectioned halves of the roots were obtained and washed with NaOCl 4%, EDTA 17% and 5% sodium thiosulfate, and sterilized by autoclaving for 15 minutes at 121°C. A multi-species biofilm broth was developed with three strains of bacteria under laboratory conditions: Enterococcus faecalis ATTC 29212, Eikenella corrodens ATTC 23834, Streptococcus anginosus ATTC 33397. Roots were autoclaved and transferred to the broth for 4 days and then were subjected to either disinfection with sodium hypochlorite 4% and XP-endo Finisher (FKG Dentaire, La Chaux-de-Fonds, Switzerland) or chlorhexidine 2% with and without activation with XP-endo Finisher (FKG Dentaire, La Chaux-de-Fonds, Switzerland).<br><br>Results: The evaluations of the biofilm elimination showed results that indicate that the 4% sodium hypochlorite group with positive pressure irrigation presented significant differences with the group that had irrigation with sodium hypochlorite activated with XP-endo Finisher and the chlorhexidine groups to 2% (P<0.05).<br><br>Conclusions: Chlorhexidine 2% activated with the XP-endo Finisher does not exert elimination or improved cleaning effect on the multi-species biofilm. Activation of sodium hypochlorite 4% improved the elimination of the multi-species biofilm. Key words:Biofilm, multispecies, chlorhexidine, sodium hypochlorite.},
}
@article {pmid31699135,
year = {2019},
author = {Theodora, NA and Dominika, V and Waturangi, DE},
title = {Screening and quantification of anti-quorum sensing and antibiofilm activities of phyllosphere bacteria against biofilm forming bacteria.},
journal = {BMC research notes},
volume = {12},
number = {1},
pages = {732},
pmid = {31699135},
issn = {1756-0500},
support = {Penelitian Dasar 2019//Ristekdikti/ ; },
abstract = {OBJECTIVE: The objectives of this research were to screen anti-quorum sensing activity of phyllosphere bacteria and quantify their antibiofilm activity against biofilm forming bacteria (Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Salmonella typhimurium, Vibrio cholerae, Pseudomonas aeruginosa).<br><br>RESULTS: We found 11 phyllosphere bacteria isolates with potential anti-quorum sensing activity. Most of the crude extracts from phyllosphere bacteria isolates had anti-quorum sensing activity against Chromobacterium violaceum at certain concentration (20 and 10 mg/mL), but not crude extract from isolate JB 7F. Crude extract showed the largest turbid zone (1,27 cm) using isolate JB 14B with concentration of 10 mg/mL and the narrowest turbid zone isolate (1 cm) using JB 18B with concentration of 10 mg/mL. Crude extracts showed various antibiofilm activities against all tested pathogenic bacteria, it showed the highest biofilm inhibition (90%) and destruction activities (76%) against S. aureus.},
}
@article {pmid31698068,
year = {2019},
author = {Vinay, TN and Ray, AK and Avunje, S and Thangaraj, SK and Krishnappa, H and Viswanathan, B and Reddy, MA and Vijayan, KK and Patil, PK},
title = {Vibrio harveyi biofilm as immunostimulant candidate for high-health pacific white shrimp, Penaeus vannamei farming.},
journal = {Fish &amp; shellfish immunology},
volume = {95},
number = {},
pages = {498-505},
doi = {10.1016/j.fsi.2019.11.004},
pmid = {31698068},
issn = {1095-9947},
abstract = {The study was to develop Vibrio harveyi biofilm-based novel microbial product and its oral delivery for high health Penaeus vannamei farming. Yield of bacterial biofilm was optimized on chitin substrate (size: <360, 360-850 and 850-1250 μm; concentration: 0.3, 0.6 and 0.9%) in tryptone soy broth (0.15%). The biofilm was characterized by crystal violet assay, SEM and LSCM imaging; protein profiling by SDS-PAGE and LC-ESI-MS/MS. The immune stimulatory effect of the biofilm in yard experiments was evaluated by relative quantification of immune genes using real-time PCR effect on overall improvement on health status under field trials. The highest biofilm yield (6.13 ± 0.2 × 107 cfu/ml) was obtained at 0.6% of <360 μm chitin substrate. The biofilm formation was stabilized by 96 h of incubation at 30 °C. Protein profiling confirmed expression of six additional proteins (SDS-PAGE) and 11 proteins were differentially expressed (LC-ESI-MS/MS) in biofilm cells over free cells of V. harveyi. Oral administration of the biofilm for 48 h confirmed to enhance expression of antimicrobial peptides, penaeidin, crustin and lysozyme in P. vannamei. Further Oral administration of biofilm for two weeks to P. vannamei (1.8 ± 0.13 g) improved the growth (2.66 ± 0.06 g) and survival (84.44 ± 1.82%) compared to control (2.15 ± 0.03 g; 70.94 ± 0.66%) Nursery trials showed a significant reduction in occurrence of anatomical deformities like antenna cut (12.67 ± 0.66%), rostrum cut (4.66 ± 0.87%), and tail rot (3.33 ± 0.88%), compared to animals fed with normal diet which was 24.33 ± 2.72; 14 ± 1.52 and 10.66 ± 1.45% respectively. In vitro and in vivo studies suggest inactivated biofilm cells of V. harveyi on chitin substrate express additional antigenic proteins and when administered orally through feed at regular intervals stimulates immune response and improve growth, survival and health status of shrimp.},
}
@article {pmid31697722,
year = {2019},
author = {Brunetti, G and Navazio, AS and Giuliani, A and Giordano, A and Proli, EM and Antonelli, G and Raponi, G},
title = {Candida blood stream infections observed between 2011 and 2016 in a large Italian University Hospital: A time-based retrospective analysis on epidemiology, biofilm production, antifungal agents consumption and drug-susceptibility.},
journal = {PloS one},
volume = {14},
number = {11},
pages = {e0224678},
pmid = {31697722},
issn = {1932-6203},
abstract = {Candida bloodstream infection (BSI) represents a growing infective problem frequently associated to biofilm production due to the utilization of intravascular devices. Candida species distribution (n = 612 strains), their biofilm production and hospital antifungal drug consumption were evaluated in different wards of a tertiary care academic hospital in Italy during the years 2011-2016. In the considered time window, an increasing number of Candida BSI (p = 0.005) and of biofilm producing strains were observed (p<0.0001). Although C. albicans was the species more frequently isolated in BSI with a major biofilm production, an increased involvement of non-albicans species was reported, particularly of C. parapsilosis that displayed a high frequency in catheter infections, and lower biofilm production compared to C. albicans. Although trends of biofilm production were substantially stable in time, a decreasing biofilm production by C. parapsilosis in the Intensive Care Unit (ICU) was observed (p = 0.0041). Principal component analysis displayed a change in antifungal drugs consumption driven by two mutually independent temporal trends, i.e. voriconazole use in the general medicine wards initially, and fluconazole use mainly in the ICU; these factors explain 68.9% and 25.7% of total variance respectively. Moreover, a significant trend (p = 0.003) in fluconazole use during the whole time period considered emerged, particularly in the ICU (p = 0.017), but also in the general medicine wards (p = 0.03). These trends paralleled with significant increase MIC90 of fluconazole (p = 0.05), particularly for C. parapsilosis in the ICU (p = 0.04), with a general and significant decreased trend of the MIC90 values of caspofungin (p = 0.04), and with significant increased MIC50 values for amphotericin B (p = 0.01) over the study period. In conclusion, drug utilization in our hospital turned out to be a putative influencing factor on the ecology of the species, on the increase in time of the biofilm producing strains and on the Candida antifungal susceptibility profile, thus influencing clinical management.},
}
@article {pmid31697703,
year = {2019},
author = {Booth, WT and Davis, RR and Deora, R and Hollis, T},
title = {Structural mechanism for regulation of DNA binding of BpsR, a Bordetella regulator of biofilm formation, by 6-hydroxynicotinic acid.},
journal = {PloS one},
volume = {14},
number = {11},
pages = {e0223387},
pmid = {31697703},
issn = {1932-6203},
support = {R01 AI075081/AI/NIAID NIH HHS/United States ; T32 GM095440/GM/NIGMS NIH HHS/United States ; },
abstract = {Bordetella bacteria are respiratory pathogens of humans, birds, and livestock. Bordetella pertussis the causative agent of whopping cough remains a significant health issue. The transcriptional regulator, BpsR, represses a number of Bordetella genes relating to virulence, cell adhesion, cell motility, and nicotinic acid metabolism. DNA binding of BpsR is allosterically regulated by interaction with 6-hydroxynicotinic acid (6HNA), the first product in the nicotinic acid degradation pathway. To understand the mechanism of this regulation, we have determined the crystal structures of BpsR and BpsR in complex with 6HNA. The structures reveal that BpsR binding of 6HNA induces a conformational change in the protein to prevent DNA binding. We have also identified homologs of BpsR in other Gram negative bacteria in which the amino acids involved in recognition of 6HNA are conserved, suggesting a similar mechanism for regulating nicotinic acid degradation.},
}
@article {pmid31695365,
year = {2019},
author = {Habibipour, R and Moradi-Haghgou, L and Farmany, A},
title = {Green synthesis of AgNPs@PPE and its Pseudomonas aeruginosa biofilm formation activity compared to pomegranate peel extract.},
journal = {International journal of nanomedicine},
volume = {14},
number = {},
pages = {6891-6899},
pmid = {31695365},
issn = {1178-2013},
abstract = {Background: Bacteria are able to form biofilm on the biotic and abiotic surfaces which helps to protect themselves from deleterious conditions, predation, desiccation, and exposure to antibacterial substances. About 80% of bacterial infections are caused by those bacteria living in the biofilm. Pseudomonas aeruginosa, a gram-negative, non-fermentative bacillus, and the ubiquitous bacterium is an important opportunistic pathogen notorious for biofilm formation and is remarkably resistant against most antibiotics multiple front-line antibiotics, which significantly contributes to eradication failure. The aim of this paper was to evaluate the anti-biofilm formation activity of Ag@PPEs gainst P. aeruginosa bacteria.<br><br>Methods: An aqueous extract of black pomegranate peel was used for the synthesis of silver nanoparticles (AgNPs@PPE). The characteristics, anti-biofilm formation and cell toxicity of AgNPs@PPE were examined in vitro.<br><br>Results: Absorbance at λmax 372 nm which is related to the surface plasmon resonance, confirms the AgNPs@PPE formation. XRD pattern showed the face-centered qubic (fcc) crystalline structure of AgNPs. TEM images showed that spherical AgNPs size is ranged between 32 and 85 nm. The AgNPs@PPE showed inhibition effect against P. aeruginosa biofilm formation at 0.1 to 0.5 mg/ml concentrations. Cell toxicity assay showed that at 400 µg/ml, AgNPs@PPE were safe without a significant toxicity in L929 cell line.<br><br>Conclusion: These data indicate that co-treatment of PPE and AgNPs@PPE significantly decreased the biofilm formation rate. Furthermore, no significant toxicity of AgNPs@PPE was shown against L929 cell line at 400 µg/ml concentration.},
}
@article {pmid31694193,
year = {2019},
author = {Alonso-Calleja, C and Gómez-Fernández, S and Carballo, J and Capita, R},
title = {Prevalence, Molecular Typing, and Determination of the Biofilm-Forming Ability of Listeria monocytogenes Serotypes from Poultry Meat and Poultry Preparations in Spain.},
journal = {Microorganisms},
volume = {7},
number = {11},
pages = {},
pmid = {31694193},
issn = {2076-2607},
support = {RTI2018-098267-R-C33//Ministerio de Ciencia, Innovación y Universidades/ ; LE164G18//Consejería de Educación, Junta de Castilla y León/ ; },
abstract = {A study was undertaken of the presence of Listeria monocytogenes in 260 samples of poultry meat obtained from retail outlets in northwestern Spain. L. monocytogenes was detected in 20 samples (7.7%). Twenty strains (one strain per positive sample) were characterized. The strains belonged to 10 serotypes: 1/2a (2 strains), 1/2b (2), 1/2c (2), 3a (1), 3b (2), 3c (2), 4a (2), 4b (4), 4c (1), and 4d (2). Cluster analysis (ribotyping; EcoRI) showed a strong genetic relationship between strains isolated from samples coming from different outlets. Ribotyping permitted some isolates of the same serotype to be differentiated, which points to the possible usefulness of this technique in the epidemiological surveillance of L. monocytogenes. All strains formed biofilm on polystyrene, as shown by confocal laser scanning microscopy. The biovolume (between 621.7 ± 36.0 µm3 and 62,984.0 ± 14,888.2 µm3 in the observational field of 14,161 μm2), percentage of surface coverage (from 2.17 ± 0.84% to 94.43 ± 3.97%), roughness (between 0.399 ± 0.052 and 0.830 ± 0.022), and maximum thickness (between 9.00 ± 0.00 µm and 24.00 ± 14.93 µm) of biofilms varied between strains (p < 0.05). These results expand knowledge of the characteristics of L. monocytogenes isolates from poultry.},
}
@article {pmid31693234,
year = {2020},
author = {Davis, RT and Brown, PD},
title = {spoT-mediated stringent response influences environmental and nutritional stress tolerance, biofilm formation and antimicrobial resistance in Klebsiella pneumoniae.},
journal = {APMIS : acta pathologica, microbiologica, et immunologica Scandinavica},
volume = {128},
number = {1},
pages = {48-60},
doi = {10.1111/apm.13006},
pmid = {31693234},
issn = {1600-0463},
support = {//University of the West Indies/ ; },
abstract = {Klebsiella pneumoniae is an important opportunistic pathogen with significant potential for virulence and multidrug resistance. Treatment failure often occurs because the pathogen may couple virulence and drug resistance with the stringent response. This study assessed the role of the spoT gene in environmental and nutritional stress tolerance, exopolysaccharide capsule production and biofilm formation. spoT mutants were constructed using the lambda red recombinase technique, and mutant and wild-type (WT) strains were exposed to limiting concentrations of carbon (glucose), phosphate and aminoacid, and environmental stresses of ethanol, salt and heat. Cell viability, capsule production and cell length were assessed as well as the ability to grow biofilm under antibiotic pressure using gentamicin and ceftazidime. spoT mutants were more susceptible to stresses versus WT; the reverse was true for survival during biofilm susceptibility assay (p < 0.05), especially when carbon and phosphate were present. spoT mutants were elongated and lacked a capsule versus WT and non-starved strains. The inability to produce capsule in mutants before and after starvation was likely a general effect of spoT mutation. These data suggest that the spoT-mediated stringent response is important for K. pneumoniae in conditions of nutrient limitation, environmental stress and antimicrobial pressure.},
}
@article {pmid31692081,
year = {2019},
author = {Tomizawa, T and Ishikawa, M and Bello-Irizarry, SN and de Mesy Bentley, KL and Ito, H and Kates, SL and Daiss, JL and Beck, C and Matsuda, S and Schwarz, EM and Nishitani, K},
title = {Biofilm Producing Staphylococcus epidermidis (RP62A Strain) Inhibits Osseous Integration Without Osteolysis and Histopathology in a Murine Septic Implant Model.},
journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society},
volume = {},
number = {},
pages = {},
doi = {10.1002/jor.24512},
pmid = {31692081},
issn = {1554-527X},
support = {2017//Fujiwara Memorial Foundation/ ; P30AR069655//Research Grant National Institute of Arthritis and Musculoskeletal and Skin Diseases/ ; P50AR072000//Research Grant National Institute of Arthritis and Musculoskeletal and Skin Diseases/ ; Clinical Priority Program//AOTrauma/ ; 16H06906//Grant-in-Aid for Research Activity start-up/ ; ISHIZUE 2017//ISHIZUE 2017 of Kyoto University Research Development Program/ ; },
abstract = {Despite its presence in orthopaedic infections, Staphylococcus epidermidis's ability to directly induce inflammation and bone destruction is unknown. Thus, we compared a clinical strain of methicillin-resistant biofilm-producing S. epidermidis (RP62A) to a highly virulent and osteolytic strain of methicillin-resistant Staphylococcus aureus (USA300) in an established murine implant-associated osteomyelitis model. Bacterial burden was assessed by colony forming units (CFUs), tissue damage was assessed by histology and micro-computed tomography, biofilm was assessed by scanning electron microscopy (SEM), host gene expression was assessed by quantitative polymerase chain reaction, and osseous integration was assessed via biomechanical push-out test. While CFUs were recovered from RP62A-contaminated implants and surrounding tissues after 14 days, the bacterial burden was significantly less than USA300-infected tibiae (p < 0.001). In addition, RP62A failed to produce any of the gross pathologies induced by USA300 (osteolysis, reactive bone formation, Staphylococcus abscess communities, marrow necrosis, and biofilm). However, fibrous tissue was present at the implant-host interface, and rigorous SEM confirmed the rare presence of cocci on RP62A-contaminated implants. Gene expression studies revealed that IL-1β, IL-6, RANKL, and TLR-2 mRNA levels in RP62A-infected bone were increased versus Sterile controls. Ex vivo push-out testing showed that RP62A-infected implants required significantly less force compared with the Sterile group (7.5 ± 3.4 vs. 17.3 ± 4.1 N; p < 0.001), but required 10-fold greater force than USA300-infected implants (0.7 ± 0.3 N; p < 0.001). Taken together, these findings demonstrate that S. epidermidis is a commensal pathogen whose mechanisms to inhibit osseous integration are limited to minimal biofilm formation on the implant, and low-grade inflammation. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.},
}
@article {pmid31691922,
year = {2019},
author = {Majumdar, M and Misra, TK and Roy, DN},
title = {In vitro anti-biofilm activity of 14-deoxy-11,12-didehydroandrographolide from Andrographis paniculata against Pseudomonas aeruginosa.},
journal = {Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]},
volume = {},
number = {},
pages = {},
doi = {10.1007/s42770-019-00169-0},
pmid = {31691922},
issn = {1678-4405},
support = {YSS/2015/001965//Department of Science and Technology, Govt of India/ ; },
abstract = {14-Deoxy-11,12-didehydroandrographolide is a biologically active molecule present in the extract of Andrographis paniculata (Kalmegh), a classic ethnic herbal formula, which has been used for over thousand years as therapeutics to treat numerous infectious diseases like upper respiratory tract infection, urinary tract infection, and many more health issues. The present study is designed to ascertain an inhibitor against biofilm formation from the major metabolites of Andrographis paniculata, because the extract of this herb shows inhibition of bacterial quorum sensing (QS) communication and biofilm development against microorganisms. 14-Deoxy-11,12-didehydroandrographolide at 0.1 mM (sub-MIC dose) with azithromycin (6 μg/mL, sub-MIC) or gentamicin (4 μg/mL, sub-MIC) synergistically inhibits 92% biofilm production by a 48-h treatment against Pseudomonas aeruginosa. Further investigation carried out by atomic force microscopy shows promising reduction in roughness and height of biofilm in the presence of 14-deoxy-11,12-didehydroandrographolide compared with the control group. The content of extracellular polymeric substances, level of pyocyanin production, and synthesis of extracellular protease by P. aeruginosa have also been reduced significantly at around 90% in 14-deoxy-11,12-didehydroandrographolide-treated group. In conclusion, 14-deoxy-11,12-didehydroandrographolide could be used as a drug molecule against biofilm development by inhibiting QS pathway in Pseudomonas aeruginosa.},
}
@article {pmid31690794,
year = {2019},
author = {Brahma, U and Sharma, P and Murthy, S and Sharma, S and Chakraborty, S and Appalaraju, SN and Bhandari, V},
title = {Decreased expression of femXAB genes and fnbp mediated biofilm pathways in OS-MRSA clinical isolates.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {16028},
pmid = {31690794},
issn = {2045-2322},
support = {2016/DST/INSPIRE/04/2015/000242//Department of Science and Technology, Ministry of Science and Technology (DST)/ ; },
abstract = {Methicillin-Resistant Staphylococcus aureus (MRSA) is a significant threat to human health. Additionally, biofilm forming bacteria becomes more tolerant to antibiotics and act as bacterial reservoir leading to chronic infection. In this study, we characterised the antibiotic susceptibility, biofilm production and sequence types (ST) of 74 randomly selected clinical isolates of S. aureus causing ocular infections. Antibiotic susceptibility revealed 74% of the isolates as resistant against one or two antibiotics, followed by 16% multidrug-resistant isolates (MDR), and 10% sensitive. The isolates were characterized as MRSA (n = 15), Methicillin-sensitive S. aureus (MSSA, n = 48) and oxacillin susceptible mecA positive S. aureus (OS-MRSA, n = 11) based on oxacillin susceptibility, mecA gene PCR and PBP2a agglutination test. All OS-MRSA would have been misclassified as MSSA on the basis of susceptibility test. Therefore, both phenotypic and genotypic tests should be included to prevent strain misrepresentation. In addition, in-depth studies for understanding the emerging OS-MRSA phenotype is required. The role of fem XAB gene family has been earlier reported in OS-MRSA phenotype. Sequence analysis of the fem XAB genes revealed mutations in fem × (K3R, H11N, N18H and I51V) and fem B (L410F) genes. The fem XAB genes were also found down-regulated in OS-MRSA isolates in comparison to MRSA. In OS-MRSA isolates, biofilm formation is regulated by fibronectin binding proteins A &amp; B. Molecular typing of the isolates revealed genetic diversity. All the isolates produced biofilm, however, MRSA isolates with strong biofilm phenotype represent a worrisome situation and may even result in treatment failure.},
}
@article {pmid31689511,
year = {2019},
author = {Demir, C and Demirci, M and Yigin, A and Tokman, HB and Cetik Yildiz, S},
title = {Presence of Biofilm and Adhesin Genes in Staphylococcus aureus Strains Taken from Chronic Wound Infections and their Genotypic and Phenotypic Antimicrobial Sensitivity Patterns.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {},
number = {},
pages = {101584},
doi = {10.1016/j.pdpdt.2019.101584},
pmid = {31689511},
issn = {1873-1597},
abstract = {The purpose of this research was to examine some biofilm (icaA, icaD and bap) and some adhesion (clfA, fnbA, cna) genes, and also assess the genotypic and phenotypic antimicrobial resistance patterns of Staphylococcus aureus strains taken from wound specimens in Mardin, Turkey. A total of 220 wound specimens were investigated. The biofilm forming ability and resistance pattern for eleven antimicrobial agents were investigated by conventional and multiplex PCR methods. S. aureus were taken from 112 (50.9%) of 220 wound specimens. Moreover, biofilm production was found in 79 (70.5%) of the 112 S. aureus isolates. 97 (86.6%) strains of all isolates were positive for icaA and icaD, and 15 (13.4%) for bap. The adhesin genes, cna, fnbA and clfA were detected in 98 (87.5%), 87 (77.7%), and 75 (66.9%) strains, respectively. The numbers of MSSA and MRSA bearing antimicrobial resistance genes were 19 (16.96%) and 32 (28.57%) for blaZ, 9 (8.04%) and 17 (15.18%) for tetK, 6 (5.36%) and 14 (12.5%) for ermC, 2 (1.79%) and 7 (6.25%) for tetM, 0 (0%) and 5 (4.46%) for mecA, 2 (1.79%) and 4 (3.57%) for ermA, 1 (0.89%) and 2 (1.79 %) for both tetK and tetM, respectively. Our findings indicate that multiplex PCR is a suitable way for identifying biofilm and adhesin producing S. aureus. Our data also provided a country-wide oversight of the S. aureus antimicrobial resistance gene profiles for the properly therapy of patients and to control the spreading of the resistance genes.},
}
@article {pmid31687841,
year = {2019},
author = {Wang, T and Flint, S and Palmer, J},
title = {Magnesium and calcium ions: roles in bacterial cell attachment and biofilm structure maturation.},
journal = {Biofouling},
volume = {35},
number = {9},
pages = {959-974},
doi = {10.1080/08927014.2019.1674811},
pmid = {31687841},
issn = {1029-2454},
abstract = {The ubiquitous divalent cations magnesium and calcium are important nutrients required by bacteria for growth and cell maintenance. Multi-faceted roles are shown both in bacterial initial attachment and biofilm maturation. The effects of calcium and magnesium can be highlighted in physio-chemical interactions, gene regulation and bio-macromolecular structural modification, which lead to either promotion or inhibition of biofilms. This review outlines recent research addressing phenotypic changes and mechanisms undertaken by calcium and magnesium in affecting bacterial biofilm formation.},
}
@article {pmid31686691,
year = {2019},
author = {Lauer Cruz, K and de Souza da Motta, A},
title = {Characterization of biofilm production by Pseudomonas fluorescens isolated from refrigerated raw buffalo milk.},
journal = {Journal of food science and technology},
volume = {56},
number = {10},
pages = {4595-4604},
pmid = {31686691},
issn = {0022-1155},
abstract = {Pseudomonas fluorescens can often be isolated from refrigerated raw milk. Two strains of P. fluorescens PL5.4 and PL7.1, isolated from raw buffalo milk, were evaluated for their proteolytic capacity, exopolysaccharide production and biofilm production. Proteolytic activity was observed in both strains. The P. fluorescens PL5.4 strain presented fluorescence in the presence of calcofluor, indicating exopolysaccharide production. Both strains were able to produce biofilm at 7 °C for 72 h. For the biofilm production test on stainless steel, adherent cell counts of up to 7.1, 7.3 and 8.8 log CFU/cm2 at 7, 23 and 30 °C were obtained. Through scanning electron microscopy, it was possible to observe the biofilm produced by the P. fluorescens PL5.4 strain. Proper cleaning and disinfection practices in order are important to reduce bacterial contamination and extend the useful life of raw material and its derivatives.},
}
@article {pmid31686149,
year = {2019},
author = {Yi, J and Zhang, D and Cheng, Y and Tan, J and Luo, Y},
title = {The impact of Paenibacillus polymyxa HY96-2 luxS on biofilm formation and control of tomato bacterial wilt.},
journal = {Applied microbiology and biotechnology},
volume = {103},
number = {23-24},
pages = {9643-9657},
pmid = {31686149},
issn = {1432-0614},
support = {2017YFD0201107-2-3//the National Key Research and Development Program of China/ ; 31501693//the National Natural Science Fund/ ; },
abstract = {The focus of this study was to investigate the effects of luxS, a key regulatory gene of the autoinducer-2 (AI-2) quorum sensing (QS) system, on the biofilm formation and biocontrol efficacy against Ralstonia solanacearum by Paenibacillus polymyxa HY96-2. luxS mutants were constructed and assayed for biofilm formation of the wild-type (WT) strain and luxS mutants of P. polymyxa HY96-2 in vitro and in vivo. The results showed that luxS positively regulated the biofilm formation of HY96-2. Greenhouse experiments of tomato bacterial wilt found that from the early stage to late stage postinoculation, the biocontrol efficacy of the luxS deletion strain was the lowest with 50.70 ± 1.39% in the late stage. However, the luxS overexpression strain had the highest biocontrol efficacy with 75.66 ± 1.94% in the late stage. The complementation of luxS could restore the biocontrol efficacy of the luxS deletion strain with 69.84 ± 1.09% in the late stage, which was higher than that of the WT strain with 65.94 ± 2.73%. Therefore, we deduced that luxS could promote the biofilm formation of P. polymyxa HY96-2 and further promoted its biocontrol efficacy against R. solanacearum.},
}
@article {pmid31685917,
year = {2019},
author = {Noirot-Gros, MF and Forrester, S and Malato, G and Larsen, PE and Noirot, P},
title = {CRISPR interference to interrogate genes that control biofilm formation in Pseudomonas fluorescens.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {15954},
pmid = {31685917},
issn = {2045-2322},
abstract = {Bacterial biofilm formation involves signaling and regulatory pathways that control the transition from motile to sessile lifestyle, production of extracellular polymeric matrix, and maturation of the biofilm 3D structure. Biofilms are extensively studied because of their importance in biomedical, ecological and industrial settings. Gene inactivation is a powerful approach for functional studies but it is often labor intensive, limiting systematic gene surveys to the most tractable bacterial hosts. Here, we adapted the CRISPR interference (CRISPRi) system for use in diverse strain isolates of P. fluorescens, SBW25, WH6 and Pf0-1. We found that CRISPRi is applicable to study complex phenotypes such as cell morphology, motility and biofilm formation over extended periods of time. In SBW25, CRISPRi-mediated silencing of genes encoding the GacA/S two-component system and regulatory proteins associated with the cylic di-GMP signaling messenger produced swarming and biofilm phenotypes similar to those obtained after gene inactivation. Combined with detailed confocal microscopy of biofilms, our study also revealed novel phenotypes associated with extracellular matrix biosynthesis as well as the potent inhibition of SBW25 biofilm formation mediated by the PFLU1114 operon. We conclude that CRISPRi is a reliable and scalable approach to investigate gene networks in the diverse P. fluorescens group.},
}
@article {pmid31685418,
year = {2019},
author = {Adnan, M and Ali Shah, MR and Jamal, M and Jalil, F and Andleeb, S and Nawaz, MA and Pervez, S and Hussain, T and Shah, I and Imran, M and Kamil, A},
title = {Isolation and characterization of bacteriophage to control multidrug-resistant Pseudomonas aeruginosa planktonic cells and biofilm.},
journal = {Biologicals : journal of the International Association of Biological Standardization},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.biologicals.2019.10.003},
pmid = {31685418},
issn = {1095-8320},
abstract = {Pseudomonas aeruginosa is Gram-negative bacterium, one of the leading cause of drug-resistant nosocomial infections in developing countries. This bacterium possesses chromosomally encoded efflux pumps, poor permeability of outer-membrane and high tendency for biofilm formation which are tools to confer resistance. Bacteriophages are regarded as feasible treatment option for control of resistant P. aeruginosa. The aim of the current study was isolate and characterized a bacteriophage against P. aeruginosa with MDR and biofilm ability. A bacteriophage MA-1 with moderate host range was isolated from waste water. The phage was considerable heat and pH stable. Electron microscopy revealed that phage MA-1 belongs to Myoviridae family. Its genome was dsDNA (≈50 kb), coding for eighteen different proteins (ranging from 12 to 250 KDa). P. aeruginosa-2949 log growth phase was significantly reduced by phage MA-1 (2.5 × 103 CFU/ml) as compared to control (without phage). Phage MA-1 also showed significant reductions of 2.0, 2.5 and 3.2 folds in 24, 48, and 74 h old biofilms after 6 h treatment with phage respectively as compared to control. It was concluded from this study that phage MA-1 has capability of killing P. aeruginosa planktonic cells and biofilm, but for complete eradication cocktail will more effective to avoid resistance.},
}
@article {pmid31685050,
year = {2019},
author = {Ribeiro, MM and Graziano, KU and Olson, N and França, R and Alfa, MJ},
title = {The polytetrafluoroethylene (PTFE) channel model of cyclic-buildup biofilm and traditional biofilm: The impact of friction, and detergent on cleaning and subsequent high-level disinfection.},
journal = {Infection control and hospital epidemiology},
volume = {},
number = {},
pages = {1-9},
doi = {10.1017/ice.2019.306},
pmid = {31685050},
issn = {1559-6834},
abstract = {OBJECTIVE: To evaluate the efficacy of detergent and friction on removal of traditional biofilm and cyclic-buildup biofilm (CBB) from polytetrafluoroethylene (PTFE) channels and to evaluate the efficacy of glutaraldehyde to kill residual bacteria after cleaning.<br><br>METHODS: PTFE channels were exposed to artificial test soil containing 108 CFU/mL of Pseudomonas aeruginosa and Enterococcus faecalis, followed by full cleaning and high-level disinfection (HLD) for five repeated rounds to establish CBB. For traditional biofilm, the HLD step was omitted. Cleaning with enzymatic and alkaline detergents, bristle brush, and Pull Thru channel cleaner were compared to a water flush only. Carbohydrate, protein, viable count, adenosine triphosphate (ATP) levels were analyzed and atomic force microscopy (AFM) was performed.<br><br>RESULTS: In the absence of friction, cleaning of traditional biofilm and CBB was not effective compared to the positive control (Dunn-Bonferroni tests; P > .05) regardless of the detergent used. ATP, protein, and carbohydrate analyses were unable to detect traditional biofilm or CBB. The AFM analysis showed that fixation resulted in CBB being smoother and more compact than traditional biofilm.<br><br>CONCLUSION: Friction during the cleaning process was a critical parameter regardless of the detergent used for removal of either traditional biofilm or CBB. Glutaraldehyde effectively killed the remaining microorganisms regardless of the cleaning method used.},
}
@article {pmid31684101,
year = {2019},
author = {Lade, H and Park, JH and Chung, SH and Kim, IH and Kim, JM and Joo, HS and Kim, JS},
title = {Biofilm Formation by Staphylococcus aureus Clinical Isolates is Differentially Affected by Glucose and Sodium Chloride Supplemented Culture Media.},
journal = {Journal of clinical medicine},
volume = {8},
number = {11},
pages = {},
doi = {10.3390/jcm8111853},
pmid = {31684101},
issn = {2077-0383},
support = {2017M3A9E4077232//National Research Foundation of Korea/ ; },
abstract = {Staphylococcus aureus (S. aureus) causes persistent biofilm-related infections. Biofilm formation by S. aureus is affected by the culture conditions and is associated with certain genotypic characteristics. Here, we show that glucose and sodium chloride (NaCl) supplementation of culture media, a common practice in studies of biofilms in vitro, influences both biofilm formation by 40 S. aureus clinical isolates (methicillin-resistant and methicillin-sensitive S. aureus) and causes variations in biofilm quantification. Methicillin-resistant strains formed more robust biofilms than methicillin-sensitive strains in tryptic soy broth (TSB). However, glucose supplementation in TSB greatly promoted and stabilized biofilm formation of all strains, while additional NaCl was less efficient in this respect and resulted in significant variation in biofilm measurements. In addition, we observed that the ST239-SCCmec (Staphylococcal Cassette Chromosome mec) type III lineage formed strong biofilms in TSB supplemented with glucose and NaCl. Links between biofilm formation and accessory gene regulator (agr) status, as assessed by δ-toxin production, and with mannitol fermentation were not found. Our results show that TSB supplemented with 1.0% glucose supports robust biofilm production and reproducible quantification of S. aureus biofilm formation in vitro, whereas additional NaCl results in major variations in measurements of biofilm formation.},
}
@article {pmid31683828,
year = {2019},
author = {Guimerà, X and Moya, A and Dorado, AD and Illa, X and Villa, R and Gabriel, D and Gamisans, X and Gabriel, G},
title = {A Minimally Invasive Microsensor Specially Designed for Simultaneous Dissolved Oxygen and pH Biofilm Profiling.},
journal = {Sensors (Basel, Switzerland)},
volume = {19},
number = {21},
pages = {},
pmid = {31683828},
issn = {1424-8220},
support = {CTQ2015-69802-C2-1-R//Ministerio de Ciencia y Tecnología/ ; },
abstract = {A novel sensing device for simultaneous dissolved oxygen (DO) and pH monitoring specially designed for biofilm profiling is presented in this work. This device enabled the recording of instantaneous DO and pH dynamic profiles within biofilms, improving the tools available for the study and the characterization of biological systems. The microsensor consisted of two parallel arrays of microelectrodes. Microelectrodes used for DO sensing were bare gold electrodes, while microelectrodes used for pH sensing were platinum-based electrodes modified using electrodeposited iridium oxide. The device was fabricated with a polyimide (Kapton®) film of 127 µm as a substrate for minimizing the damage caused on the biofilm structure during its insertion. The electrodes were covered with a Nafion® layer to increase sensor stability and repeatability and to avoid electrode surface fouling. DO microelectrodes showed a linear response in the range 0-8 mg L-1, a detection limit of 0.05 mg L-1, and a sensitivity of 2.06 nA L mg-1. pH electrodes showed a linear super-Nernstian response (74.2 ± 0.7 mV/pH unit) in a wide pH range (pH 4-9). The multi-analyte sensor array was validated in a flat plate bioreactor where simultaneous and instantaneous pH and DO profiles within a sulfide oxidizing biofilm were recorded. The electrodes spatial resolution, the monitoring sensitivity, and the minimally invasive features exhibited by the proposed microsensor improved biofilm monitoring performance, enabling the quantification of mass transfer resistances and the assessment of biological activity.},
}
@article {pmid31682418,
year = {2019},
author = {Nisbett, LM and Binnenkade, L and Bacon, B and Hossain, S and Kotloski, NJ and Brutinel, ED and Hartmann, R and Drescher, K and Arora, DP and Muralidharan, S and Thormann, KM and Gralnick, JA and Boon, EM},
title = {NosP Signaling Modulates the NO/H-NOX-Mediated Multicomponent c-Di-GMP Network and Biofilm Formation in Shewanella oneidensis.},
journal = {Biochemistry},
volume = {58},
number = {48},
pages = {4827-4841},
doi = {10.1021/acs.biochem.9b00706},
pmid = {31682418},
issn = {1520-4995},
support = {R01 GM118894/GM/NIGMS NIH HHS/United States ; T32 GM092714/GM/NIGMS NIH HHS/United States ; },
abstract = {Biofilms form when bacteria aggregate in a self-secreted exopolysaccharide matrix; they are resistant to antibiotics and implicated in disease. Nitric oxide (NO) is known to mediate biofilm formation in many bacteria via ligation to H-NOX (heme-NO/oxygen binding) domains. Most NO-responsive bacteria, however, lack H-NOX domain-containing proteins. We have identified another NO-sensing protein (NosP), which is predicted to be involved in two-component signaling and biofilm regulation in many species. Here, we demonstrate that NosP participates in the previously described H-NOX/NO-responsive multicomponent c-di-GMP signaling network in Shewanella oneidensis. Strains lacking either nosP or its co-cistronic kinase nahK (previously hnoS) produce immature biofilms, while hnoX and hnoK (kinase responsive to NO/H-NOX) mutants result in wild-type biofilm architecture. We demonstrate that NosP regulates the autophosphorylation activity of NahK as well as HnoK. HnoK and NahK have been shown to regulate three response regulators (HnoB, HnoC, and HnoD) that together comprise a NO-responsive multicomponent c-di-GMP signaling network. Here, we propose that NosP/NahK adds regulation on top of H-NOX/HnoK to modulate this c-di-GMP signaling network, and ultimately biofilm formation, by governing the flux of phosphate through both HnoK and NahK. In addition, it appears that NosP and H-NOX act to counter each other in a push-pull mechanism; NosP/NahK promotes biofilm formation through inhibition of H-NOX/HnoK signaling, which itself reduces the extent of biofilm formation. Addition of NO results in a reduction of c-di-GMP and biofilm formation, primarily through disinhibition of HnoK activity.},
}
@article {pmid31681870,
year = {2019},
author = {Kumari, P and Arora, N and Chatrath, A and Gangwar, R and Pruthi, V and Poluri, KM and Prasad, R},
title = {Delineating the Biofilm Inhibition Mechanisms of Phenolic and Aldehydic Terpenes against Cryptococcus neoformans.},
journal = {ACS omega},
volume = {4},
number = {18},
pages = {17634-17648},
pmid = {31681870},
issn = {2470-1343},
abstract = {The recalcitrant biofilm formed by fungus Cryptococcus neoformans is a life-threatening pathogenic condition responsible for further intensifying cryptococcosis. Considering the enhanced biofilm resistance and toxicity of synthetic antifungal drugs, the search for efficient, nontoxic, and cost-effective natural therapeutics has received a major boost. Phenolic (thymol and carvacrol) and aldehydic (citral) terpenes are natural and safe alternatives capable of efficient microbial biofilm inhibition. However, the biofilm inhibition mechanism of these terpenes still remains unclear. In this study, we adopted an integrative biophysical and biochemical approach to elucidate the hierarchy of their action against C. neoformans biofilm cells. The microscopic analysis revealed disruption of the biofilm cell surface with elevation in surface roughness and reduction in cell height. Although all terpenes acted through ergosterol biosynthesis inhibition, the phenolic terpenes also selectively interacted via ergosterol binding. Further, the alterations in the fatty acid profile in response to terpenes attenuated the cell membrane fluidity with enhanced permeability, resulting in pore formation and efflux of the K+/intracellular content. Additionally, mitochondrial depolarization caused higher levels of reactive oxygen species, which led to increased lipid peroxidation and activation of the antioxidant defense system. Indeed, the oxidative stress caused a significant decline in the amount of extracellular polymeric matrix and capsule sugars (mannose, xylose, and glucuronic acid), leading to a reduced capsule size and an overall negative charge on the cell surface. This comprehensive data revealed the mechanistic insights into the mode of action of terpenes on biofilm inhibition, which could be exploited for formulating novel anti-biofilm agents.},
}
@article {pmid31681633,
year = {2019},
author = {Swetha, TK and Pooranachithra, M and Subramenium, GA and Divya, V and Balamurugan, K and Pandian, SK},
title = {Umbelliferone Impedes Biofilm Formation and Virulence of Methicillin-Resistant Staphylococcus epidermidis via Impairment of Initial Attachment and Intercellular Adhesion.},
journal = {Frontiers in cellular and infection microbiology},
volume = {9},
number = {},
pages = {357},
pmid = {31681633},
issn = {2235-2988},
abstract = {Staphylococcus epidermidis is an opportunistic human pathogen, which is involved in numerous nosocomial and implant associated infections. Biofilm formation is one of the prime virulence factors of S. epidermidis that supports its colonization on biotic and abiotic surfaces. The global dissemination of three lineages of S. epidermidis superbugs highlights its clinical significance and the imperative need to combat its pathogenicity. Thus, in the current study, the antibiofilm activity of umbelliferone (UMB), a natural product of the coumarin family, was assessed against methicillin-resistant S. epidermidis (MRSE). UMB exhibited significant antibiofilm activity (83%) at 500 μg/ml concentration without growth alteration. Microscopic analysis corroborated the antibiofilm potential of UMB and unveiled its potential to impair intercellular adhesion, which was reflected in auto-aggregation and solid phase adherence assays. Furthermore, real time PCR analysis revealed the reduced expression of adhesion encoding genes (icaD, atlE, aap, bhp, ebh, sdrG, and sdrF). Down regulation of agrA and reduced production of secreted hydrolases upon UMB treatment were speculated to hinder invasive lifestyle of MRSE. Additionally, UMB hindered slime synthesis and biofilm matrix components, which were believed to augment antibiotic susceptibility. In vivo assays using Caenorhabditis elegans divulged the non-toxic nature of UMB and validated the antibiofilm, antivirulence, and antiadherence properties of UMB observed in in vitro assays. Thus, UMB impairs MRSE biofilm by turning down the initial attachment and intercellular adhesion. Altogether, the obtained results suggest the potent antibiofilm activity of UMB and the feasibility of using it in clinical settings for combating S. epidermidis infections.},
}
@article {pmid31680469,
year = {2019},
author = {Nakagami, G and Schultz, G and Kitamura, A and Minematsu, T and Akamata, K and Suga, H and Kurita, M and Hayashi, C and Sanada, H},
title = {Rapid detection of biofilm by wound blotting following sharp debridement of chronic pressure ulcers predicts wound healing: A preliminary study.},
journal = {International wound journal},
volume = {},
number = {},
pages = {},
doi = {10.1111/iwj.13256},
pmid = {31680469},
issn = {1742-481X},
support = {17H04455//Japan Society for the Promotion of Science/ ; },
abstract = {For optimal wound bed preparation, wound debridement is essential to eliminate bacterial biofilms. However, it is challenging for clinicians to determine whether the biofilm is completely removed. A newly developed biofilm detection method based on wound blotting technology may be useful. Thus, we aimed to investigate the effect of biofilm elimination on wound area decrease in pressure ulcers, as confirmed using the wound blotting method. In this retrospective observational study, we enrolled patients with pressure ulcers who underwent sharp debridement with pre- and post-debridement wound blotting. Biofilm was detected on the nitrocellulose membrane using ruthenium red or alcian blue staining. Patients were included if the test was positive for biofilm before wound debridement. Percent decrease in wound area after 1 week was calculated as an outcome measure. We classified the wounds into a biofilm-eliminated group and a biofilm-remaining group based on the post-debridement wound blotting result. Sixteen wound blotting samples from nine pressure ulcers were collected. The percent decrease in wound area was significantly higher in the biofilm-eliminated group (median: 14.4%, interquartile range: 4.6%-20.1%) than in the biofilm-remaining group (median: -14.5%, interquartile range: -25.3%-9.6%; P = .040). The presence of remaining biofilms was an independent predictor for reduced percent decrease in wound area (coefficient = -22.84, P = .040). Biofilm-based wound care guided by wound blotting is a promising measure to help clinicians eliminate bacterial bioburden more effectively for wound area reduction.},
}
@article {pmid31680421,
year = {2019},
author = {Røder, HL and Liu, W and Sørensen, SJ and Madsen, JS and Burmølle, M},
title = {Interspecies interactions reduce selection for a biofilm-optimized variant in a four-species biofilm model.},
journal = {Environmental microbiology reports},
volume = {11},
number = {6},
pages = {835-839},
doi = {10.1111/1758-2229.12803},
pmid = {31680421},
issn = {1758-2229},
support = {BK20190703//Natural Science Foundation of Jiangsu Province, China/International ; 19KJB530010//Natural Science Foundation of the Higher Education Instructions of Jiangsu Province, China/International ; R250-2017-1392//Lundbeckfonden/International ; NNF17OC0027620//Novo Nordisk Foundation/International ; 10098//Villum Fonden/International ; },
abstract = {Multispecies biofilms are structured and spatially defined communities, where interspecies interactions impact assembly and functionality. Here, we compared the spatial organization and growth of bacterial cells in differently composed biofilm communities over time to determine links between interspecies interactions and selection for biofilm phenotypes of individual species. An established model community consisting of Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus was used. It was found that interspecies interactions led to varying levels of selection for a new colony phenotype of X. retroflexus, depending on the presence/absence of other species. When M. oxydans was absent, X. retroflexus was not able to establish in the top layers of the biofilm, which led to selection for a hyper-matrix forming phenotype of X. retroflexus that successfully established in the biofilm top layers. No such phenotypic X. retroflexus variants were identified in the presence of M. oxydans. These findings indicate that interspecies interactions may lead to favourable localization of individual species in a multispecies biofilm and thereby reduce selection for competitive phenotypes.},
}
@article {pmid31679132,
year = {2019},
author = {Gabriel, C and Grenho, L and Cerqueira, F and Medeiros, R and Dias, AM and Ribeiro, AI and Proença, MF and Fernandes, MH and Sousa, JC and Monteiro, FJ and Ferraz, MP},
title = {Inhibitory Effect of 5-Aminoimidazole-4-Carbohydrazonamides Derivatives Against Candida spp. Biofilm on Nanohydroxyapatite Substrate.},
journal = {Mycopathologia},
volume = {184},
number = {6},
pages = {775-786},
pmid = {31679132},
issn = {1573-0832},
support = {PTDC/SAU-BMA/111233/2009//Fundação para a Ciência e a Tecnologia/ ; SFRH/BD/72866/2010//Fundação para a Ciência e a Tecnologia/ ; },
abstract = {Candida can adhere and form biofilm on biomaterials commonly used in medical devices which is a key attribute that enhances its ability to cause infections in humans. Furthermore, biomaterial-related infections represent a major therapeutic challenge since Candida biofilms are implicated in antifungal therapies failure. The goals of the present work were to investigate the effect of three 5-aminoimidazole-4-carbohydrazonamides, namely (Z)-5-amino-1-methyl-N'-aryl-1H-imidazole-4-carbohydrazonamides [aryl = phenyl (1a), 4-fluorophenyl (1b), 3-fluorophenyl (1c)], on Candida albicans and Candida krusei biofilm on nanohydroxyapatite substrate, a well-known bioactive ceramic material. To address these goals, both quantitative methods (by cultivable cell numbers) and qualitative evaluation (by scanning electron microscopy) were used. Compounds cytocompatibility towards osteoblast-like cells was also evaluated after 24 h of exposure, through resazurin assay. The three tested compounds displayed a strong inhibitory effect on biofilm development of both Candida species as potent in vitro activity against C. albicans sessile cells. Regarding cytocompatibility, a concentration-dependent effect was observed. Together, these findings indicated that the potent activity of imidazole derivatives on Candida spp. biofilms on nanohydroxyapatite substrate, in particular compound 1c, is worth further investigating.},
}
@article {pmid31678888,
year = {2020},
author = {Zhang, H and Wang, H and Jie, M and Zhang, K and Qian, Y and Ma, J},
title = {Performance and microbial communities of different biofilm membrane bioreactors with pre-anoxic tanks treating mariculture wastewater.},
journal = {Bioresource technology},
volume = {295},
number = {},
pages = {122302},
doi = {10.1016/j.biortech.2019.122302},
pmid = {31678888},
issn = {1873-2976},
mesh = {Biofilms ; Bioreactors ; Membranes, Artificial ; *Microbiota ; Sewage ; Waste Disposal, Fluid ; *Waste Water ; },
abstract = {The performance of pollutant removals, activated sludge characteristics, and microbial communities of two biofilm membrane bioreactors coupled with pre-anoxic tanks (BF-AO-MBRs) (one using fiber bundle bio-carriers (FB-MBR) and the other using suspended bio-carriers (MB-MBR)) were compared at the salinity between zero and 60 g/L. At all salinities, three bioreactors showed good COD average removal efficiencies (>94.1%), and FB-MBR showed the best TN removal efficiency (90.4% at 30 g/L salinity). Moreover, FB-MBR had the faster process start-up time and better salt shock resistance. At high salinities (30-60 g/L), more extracellular polymeric substances were produced by the BF-AO-MBRs to avoid the penetration of salt and protect the bacterial community. Because of the different attachment patterns of biofilms, the microbial community structure in the FB-MBR exposed to 30 g/L salinity had higher nitrite-oxidizing/ammonia-oxidizing bacteria ratio (6.44) with more abundance of denitrifiers, which contribute to higher TN removal efficiency and lower nitrite accumulation.},
}
@article {pmid31678321,
year = {2019},
author = {D'Andrea, MM and Frezza, D and Romano, E and Marmo, P and De Angelis, LH and Perini, N and Thaller, MC and Di Lallo, G},
title = {The lytic bacteriophage vB_EfaH_EF1TV, a new member of the Herelleviridae family, disrupts biofilm produced by Enterococcus faecalis clinical strains.},
journal = {Journal of global antimicrobial resistance},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jgar.2019.10.019},
pmid = {31678321},
issn = {2213-7173},
abstract = {OBJECTIVES: The aim of this study is to characterize a new bacteriophage able to infect Enterococcus faecalis, and to evaluate its ability to disrupt biofilm.<br><br>METHODS: The vB_EfaH_EF1TV (EF1TV) host-range was determined by spot test and efficiency of plating using a collection of 15E. faecalis clinical strains. The phage genome was sequenced with a next generation sequencing approach. Anti-biofilm activity was tested by crystal violet method and confocal laser scanning microscopy. Phage-resistant mutants were selected and sequenced to investigate receptors exploited by phage for infection.<br><br>RESULTS: EF1TV is a newly discoveredE. faecalis phage which belongs to the Herelleviridae family. EF1TV, whose genome is 98% identical to φEF24C, is characterized by a linear dsDNA genome of 143,507 bp with direct terminal repeats of 1,911 bp. The phage is able to infect E. faecalis and shows also the ability to degrade biofilm produced by strains of this species. The results were confirmed by confocal laser scanning microscopy analyzing the biofilm reduction in the same optical field before and after phage infection.<br><br>CONCLUSIONS: The EF1TV phage shows promising features such as an obligatory lytic nature, an anti-biofilm activity and the absence of integration-related proteins, antibiotic resistance determinants and virulence factors, and therefore could be a promising tool for therapeutic applications.},
}
@article {pmid31677806,
year = {2020},
author = {Rathinam, NK and Gorky, and Bibra, M and Salem, DR and Sani, RK},
title = {Bioelectrochemical approach for enhancing lignocellulose degradation and biofilm formation in Geobacillus strain WSUCF1.},
journal = {Bioresource technology},
volume = {295},
number = {},
pages = {122271},
doi = {10.1016/j.biortech.2019.122271},
pmid = {31677806},
issn = {1873-2976},
mesh = {Biofilms ; Biomass ; Cellulose ; *Geobacillus ; Lignin ; Zea mays ; },
abstract = {Investigations on microbial electrocatalysis as a strategy for enhancing the rates of substrate utilization leading to enhanced yield of biomass and enhanced biofilm formation are reported. A thermophilic Geobacillus sp. strain WSUCF1 (60 °C), a potential lignocellulose degrading microorganism was used as the electrocatalyst. Glucose, cellulose, and corn stover were used as the feedstocks. The results of this investigation showed that applying the oxidation potential of -0.383 mV (vs PRE) increased the glucose utilization and COD removal by 25.5% and 29.7% respectively. The bioelectrocatalysis strategy also increased the biomass yield by 81.2, 42.1, and 49.5% in the case of systems fed with glucose, cellulose, and corn stover, respectively, when compared with the systems without applied oxidation potential. This is the first work reporting the effects of applied oxidation potential on increasing the rates of degradation of lignocellulosic biomass and enhanced biofilm formation.},
}
@article {pmid31677404,
year = {2020},
author = {Li, H and Song, HL and Xu, H and Lu, Y and Zhang, S and Yang, YL and Yang, XL and Lu, YX},
title = {Effect of the coexposure of sulfadiazine, ciprofloxacin and zinc on the fate of antibiotic resistance genes, bacterial communities and functions in three-dimensional biofilm-electrode reactors.},
journal = {Bioresource technology},
volume = {296},
number = {},
pages = {122290},
doi = {10.1016/j.biortech.2019.122290},
pmid = {31677404},
issn = {1873-2976},
mesh = {*Anti-Bacterial Agents ; Bacteria ; Biofilms ; *Ciprofloxacin ; Drug Resistance, Microbial ; Electrodes ; Genes, Bacterial ; Residence Characteristics ; Sulfadiazine ; Waste Water ; Zinc ; },
abstract = {Three-dimensional biofilm electrode reactors (3D-BERs) with high treatment efficiency were constructed to treat wastewater containing sulfadiazine (SDZ) and ciprofloxacin (CIP) coexposure with Zinc (Zn). The results showed that coexposure to target antibiotics and Zn increased the absolute and relative abundances of target antibiotic resistance genes (ARGs). Additionally, the target ARG abundances were higher on cathode of 3D-BER compared with ordinary anaerobic reactor while the abundances of total ARGs were decreased in the effluent. Meanwhile, redundancy analysis results revealed that the composition of bacteria carrying ARGs was greatly influenced in the cathode by the accumulation of Zn and antibiotic, which dominated the changes of ARG abundances. Additionally, ARGs with their host bacteria revealed by network analysis were partially deposited on electrode substrates when being removed from wastewater. Thus, 3D-BER exhibits capability of simultaneously eliminating antibiotic and Zn, and greatly reduces the risks of ARGs spread.},
}
@article {pmid31676401,
year = {2020},
author = {Kipanga, PN and Liu, M and Panda, SK and Mai, AH and Veryser, C and Van Puyvelde, L and De Borggraeve, WM and Van Dijck, P and Matasyoh, J and Luyten, W},
title = {Biofilm inhibiting properties of compounds from the leaves of Warburgia ugandensis Sprague subsp ugandensis against Candida and staphylococcal biofilms.},
journal = {Journal of ethnopharmacology},
volume = {248},
number = {},
pages = {112352},
doi = {10.1016/j.jep.2019.112352},
pmid = {31676401},
issn = {1872-7573},
abstract = {Warburgia ugandensis Sprague subspecies ugandensis is a plant widely distributed in Eastern, Central and Southern Africa. In humans, it is used to treat respiratory infections, tooth aches, malaria, skin infections, venereal diseases, diarrhea, fevers and aches.<br><br>AIM OF THE STUDY: This study aims to identify the bioactive compounds against clinically important biofilm-forming strains of Candida and staphylococci that are responsible for tissue and implanted device-related infections.<br><br>METHODS: Using a bioassay-guided fractionation approach, hexane -, ethanol -, acetone - and water extracts from the leaves of W. ugandensis, their subsequent fractions and isolated compounds were tested against both developing and preformed 24 h-biofilms of Candida albicans SC5314, Candida glabrata BG2, Candida glabrata ATCC 2001, Staphylococcus epidermidis 1457 and Staphylococcus aureus USA 300 using microtiter susceptibility tests. Planktonic cells were also tested in parallel for comparison purposes. Confocal scanning laser microscopy was also used to visualize effects of isolated compounds on biofilm formation.<br><br>RESULTS: Warburganal, polygodial and alpha-linolenic acid (ALA) were the major bioactive compounds isolated from the acetone extract of W. ugandensis. For both warburganal and polygodial, the biofilm inhibitory concentration that inhibits 50% of C. albicans developing biofilms (BIC50) was 4.5 ± 1 and 10.8 ± 5 μg/mL respectively. Against S. aureus developing biofilms, this value was 37.9 ± 8 μg/mL and 25 μg/mL with warburganal and ALA respectively. Eradication of preformed 24 h biofilms was also observed. Interestingly, synergy between the sesquiterpenoids and azoles against developing C. albicans biofilms resulted in an approximately ten-fold decrease of the effective concentration required to completely inhibit growth of the biofilms by individual compounds. The hydroxyl group in position C-9 in warburganal was identified as essential for activity against staphylococcal biofilms. We also identified additional promising bioactive sesquiterpenoids; drimenol and drimendiol from the structure-activity relationship (SAR) studies.<br><br>CONCLUSIONS: ALA and four sesquiterpenoids: polygodial, warburganal, drimenol and drimendiol, have shown biofilm-inhibitory activity that has not been reported before and is worth following up. These compounds are potential drug candidates to manage biofilm-based infections, possibly in combination with azoles.},
}
@article {pmid31675521,
year = {2020},
author = {Zhang, X and Song, Z and Hao Ngo, H and Guo, W and Zhang, Z and Liu, Y and Zhang, D and Long, Z},
title = {Impacts of typical pharmaceuticals and personal care products on the performance and microbial community of a sponge-based moving bed biofilm reactor.},
journal = {Bioresource technology},
volume = {295},
number = {},
pages = {122298},
doi = {10.1016/j.biortech.2019.122298},
pmid = {31675521},
issn = {1873-2976},
mesh = {Biofilms ; *Bioreactors ; *Microbiota ; Nitrogen ; Waste Disposal, Fluid ; Waste Water ; },
abstract = {Four lab-scale moving bed biofilm reactors (MBBRs) were built to treat simulated wastewater containing typical pharmaceuticals and personal care products (PPCPs). The efficiency in removing different PPCPs at different concentrations (1, 2 and 5 mg/L) and their effects on the performance of MBBRs were investigated. Results showed that the average removal efficiencies of sulfadiazine, ibuprofen and carbamazepine were 61.1 ± 8.8%, 74.9 ± 8.8% and 28.3 ± 7.4%, respectively. Compared to the reactor without PPCPs, the total nitrogen (TN) removal efficiency of the reactors containing sulfadiazine, ibuprofen and carbamazepine declined by 21%, 30% and 42%, respectively. Based on the microbial community analysis, increasing the PPCPs concentration within a certain range (<2 mg/L) could stimulate microbial growth and increase microbial diversity yet the diversity reduced when the concentration (5 mg/L) exceeded the tolerance of microorganisms. Furthermore the presence and degradation of different PPCPs resulted in a different kind of microbial community structure in the MBBRs.},
}
@article {pmid31675193,
year = {2019},
author = {Tomiyama, K and Shiiya, T and Watanabe, K and Hamada, N and Mukai, Y},
title = {Effect of toothpaste containing multiple ions-releasing filler on polymicrobial biofilm regrowth and dentin demineralization.},
journal = {American journal of dentistry},
volume = {32},
number = {5},
pages = {245-250},
pmid = {31675193},
issn = {0894-8275},
mesh = {Animals ; Biofilms ; Cattle ; Dentin ; Fluorides ; *Tooth Demineralization ; *Toothpastes ; },
abstract = {PURPOSE: To compare the efficacy of toothpaste containing surface pre-reacted glass-ionomer (S-PRG) filler particles to that of conventional sodium fluoride (NaF) toothpaste for the prevention of dentin demineralization and biofilm regrowth.<br><br>METHODS: Bovine root dentin specimens and glass coverslips were used as biofilm growth substrates. To establish biofilms, glass and dentin specimens were incubated for 72 hours in 0.2% sucrose McBain medium inoculated with stimulated saliva from a single donor. Specimens then received a single 5-minute treatment with S-PRG toothpaste, fluoride toothpaste, or sterilized deionized water and were incubated in McBain medium for 120 hours to allow biofilm regrowth. Output parameters during regrowth (72-192 hours) were pH of spent medium, colony-forming unit (CFU) counts of biofilms, and dentin mineral profiles, integrated mineral loss (IML: vol% × µm), and lesion depth (Ld). Treatment group differences were tested by one-way ANOVA followed by Tukey's multiple range test (P< 0.05).<br><br>RESULTS: At 144 hours, medium pH was significantly higher in the S-PRG-treated dentin group than in the NaF-treated dentin group. In addition, at 192 hours, the CFU count, IML, and Ld were lower in the S-PRG-treated dentin group than in the NaF-treated dentin group. There were significant differences of pH among dentin groups at 72 hours. Treatment with S-PRG toothpaste markedly inhibited dentin demineralization compared to that with NaF toothpaste.<br><br>CLINICAL SIGNIFICANCE: Toothpaste containing multiple ions-releasing filler suppressed bacterial viability and inhibited dentin demineralization.},
}
@article {pmid31673743,
year = {2019},
author = {Ding, XS and Zhao, B and An, Q and Tian, M and Guo, JS},
title = {Role of extracellular polymeric substances in biofilm formation by Pseudomonas stutzeri strain XL-2.},
journal = {Applied microbiology and biotechnology},
volume = {103},
number = {21-22},
pages = {9169-9180},
doi = {10.1007/s00253-019-10188-4},
pmid = {31673743},
issn = {1432-0614},
support = {51208534//National Natural Science Foundation of China/ ; cstc2018jscx-msybX0308//Technical Innovation and Application Demonstration Project of CQ CSTC/ ; },
abstract = {Pseudomonas stutzeri strain XL-2 exhibited significant performance on biofilm formation. Extracellular polymeric substances (EPS) secreted by strain XL-2 were characterized by colorimetry and Fourier transform infrared (FT-IR) spectroscopy. The biofilm growth showed a strong positive correlation (rP=0.96, P<0.01) to extracellular protein content, but no correlation to exopolysaccharide content. Hydrolyzing the biofilm with proteinase K caused a significant decrease in biofilm growth (t=3.7, P<0.05), whereas the changes in biofilm growth were not significant when the biofilm was hydrolyzed by α-amylase and β-amylase, implying that proteins rather than polysaccharides played the dominant role in biofilm formation. More specifically, confocal laser scanning microscopy (CLSM) revealed that the extracellular proteins were tightly bound to the cells, resulting in the cells with EPS presenting more biofilm promotion protein secondary structures, such as three-turn helices, β-sheet, and α-helices, than cells without EPS. Both bio-assays and quantitative analysis demonstrated that strain XL-2 produced signal molecules of N-acylhomoserine lactones (AHLs) during biofilm formation process. The concentrations of C6-HLS and C6-oxo-HLS were both significantly positively correlated with protein contents (P<0.05). Dosing exogenous C6-HLS and C6-oxo-HLS also resulted in the increase in protein content. Therefore, it was speculated that C6-HLS and C6-oxo-HLS released by strain XL-2 could up-regulate the secretion of proteins in EPS, and thus promote the formation of biofilm.},
}
@article {pmid31673531,
year = {2019},
author = {Asadian, M and Azimi, L and Alinejad, F and Ostadi, Y and Lari, AR},
title = {Molecular Characterization of Acinetobacter baumannii Isolated from Ventilator-Associated Pneumonia and Burn Wound Colonization by Random Amplified Polymorphic DNA Polymerase Chain Reaction and the Relationship between Antibiotic Susceptibility and Biofilm Production.},
journal = {Advanced biomedical research},
volume = {8},
number = {},
pages = {58},
pmid = {31673531},
issn = {2277-9175},
abstract = {Background: Multidrug-resistant Acinetobacter baumannii can cause complications in antibiotic therapy and increase the rate of morbidity and mortality in hospitalized patients. Patients with ventilator and burns are two specific groups at high risk for A. baumannii infections. This study aimed to determine antibiotic susceptibility patterns associated with biofilm production in A. baumannii and to assess its molecular epidemiology by random amplified polymorphic DNA polymerase chain reaction (RAPD PCR) in A. baumannii isolated from ventilator-associated pneumonia and burn wound colonization.<br><br>Materials and Methods: In this study, 79 isolates of A. baumannii (32 ventilator-associated pneumonia [VAP] 47 burns) were collected in two teaching hospitals in Tehran, Iran, in 2018. Conventional biochemical and microbiological methods were used to identify bacteria. Antibiotic susceptibility was detected by disc diffusion methods according to the Clinical and Laboratory Standards Institute 2018. Tube test was examined for the detection of the biofilm formation rate in collected strains. The most prevalent carbapenemase genes were detected by PCR and molecular typing by RAPD PCR.<br><br>Results: All of bacteria were extensively drug-resistant (XDR) except for two isolates. The results of tube test indicated that only 36% of XDR strains were in weak rate of biofilm formation group. Two major clonal genetic groups were found in VAP and burn strains. Oxa-23 was the most prevalent carbapenemase in collected A. baumannii.<br><br>Conclusion: The presence of XDR strains of A. baumannii is considerable significant problem in hospitals. Further, similar genetic clonal identified in them indicated the nosocomial infection origin. Hence, these results are very important for control of nosocomial infection committee in health-care systems.},
}
@article {pmid31673005,
year = {2019},
author = {Brown, JL and Johnston, W and Delaney, C and Rajendran, R and Butcher, J and Khan, S and Bradshaw, D and Ramage, G and Culshaw, S},
title = {Biofilm-stimulated epithelium modulates the inflammatory responses in co-cultured immune cells.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {15779},
pmid = {31673005},
issn = {2045-2322},
support = {BB/P504567/1//RCUK | Biotechnology and Biological Sciences Research Council (BBSRC)/ ; N/A//GlaxoSmithKline (GlaxoSmithKline plc.)/ ; },
abstract = {The gingival epithelium is a physical and immunological barrier to the microbiota of the oral cavity, which interact through soluble mediators with the immune cells that patrol the tissue at the gingival epithelium. We sought to develop a three-dimensional gingivae-biofilm interface model using a commercially available gingival epithelium to study the tissue inflammatory response to oral biofilms associated with &quot;health&quot;, &quot;gingivitis&quot; and &quot;periodontitis&quot;. These biofilms were developed by sequential addition of microorganisms to mimic the formation of supra- and sub-gingival plaque in vivo. Secondly, to mimic the interactions between gingival epithelium and immune cells in vivo, we integrated peripheral blood mononuclear cells and CD14+ monocytes into our three-dimensional model and were able to assess the inflammatory response in the immune cells cultured with and without gingival epithelium. We describe a differential inflammatory response in immune cells cultured with epithelial tissue, and more so following incubation with epithelium stimulated by &quot;gingivitis-associated&quot; biofilm. These results suggest that gingival epithelium-derived soluble mediators may control the inflammatory status of immune cells in vitro, and therefore targeting of the epithelial response may offer novel therapies. This multi-cellular interface model, both of microbial and host origin, offers a robust in vitro platform to investigate host-pathogens at the epithelial surface.},
}
@article {pmid31671860,
year = {2019},
author = {Zhang, Q and Chen, X and Wu, H and Luo, W and Liu, X and Feng, L and Zhao, T},
title = {Comparison of Clay Ceramsite and Biodegradable Polymers as Carriers in Pack-bed Biofilm Reactor for Nitrate Removal.},
journal = {International journal of environmental research and public health},
volume = {16},
number = {21},
pages = {},
pmid = {31671860},
issn = {1660-4601},
abstract = {In recent years, there is a trend of low C/N ratio in municipal domestic wastewater, which results in serious problems for nitrogen removal from wastewater. The addition of an external soluble carbon source has been the usual procedure to achieve denitrification. However, the disadvantage of this treatment process is the need of a closed, rather sophisticated and costly process control as well as the risk of overdosing. Solid-phase denitrification using biodegradable polymers as biofilm carrier and carbon source was considered as an attractive alternative for biological denitrification. The start-up time of the novel process using PCL (polycaprolactone) as biofilm carrier and carbon source was comparable with that of conventional process using ceramsite as biofilm carrier and acetate as carbon source. Further, the solid-phase denitrification process showed higher nitrogen removal efficiency under shorter hydraulic retention time (HRT) and low carbon to nitrogen (C/N) ratio since the biofilm was firmly attached to the clear pores on the surface of PCL carriers and in this process bacteria that could degrade PCL carriers to obtain electron donor for denitrification was found. In addition, solid-phase denitrification process had a stronger resistance of shock loading than that in conventional process. This study revealed, for the first time, that the physical properties of the biodegradable polymer played a vital role in denitrification, and the different microbial compositions of the two processes was the main reason for the different denitrification performances under low C/N ratio.},
}
@article {pmid31671533,
year = {2019},
author = {Alshanta, OA and Shaban, S and Nile, CJ and McLean, W and Ramage, G},
title = {Candida albicans Biofilm Heterogeneity and Tolerance of Clinical Isolates: Implications for Secondary Endodontic Infections.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/antibiotics8040204},
pmid = {31671533},
issn = {2079-6382},
abstract = {AIM: Endodontic infections are caused by the invasion of various microorganisms into the root canal system. Candida albicans is a biofilm forming yeast and the most prevalent eukaryotic microorganism in endodontic infections. In this study we investigated the ability of C. albicans to tolerate treatment with standard endodontic irrigants NaOCl (sodium hypochlorite), ethylenediaminetetraacetic acid (EDTA) and a combination thereof. We hypothesized that biofilm formed from a panel of clinical isolates differentially tolerate disinfectant regimens, and this may have implications for secondary endodontic infections.<br><br>METHODOLOGY: Mature C. albicans biofilms were formed from 30 laboratory and oral clinical isolates and treated with either 3% NaOCl, 17% EDTA or a sequential treatment of 3% NaOCl followed by 17% EDTA for 5 min. Biofilms were then washed, media replenished and cells reincubated for an additional 24, 48 and 72 h at 37 °C. Regrowth was quantified using metabolic reduction, electrical impedance, biofilm biomass and microscopy at 0, 24, 48 and 72 h.<br><br>RESULTS: Microscopic analysis and viability readings revealed a significant initial killing effect by NaOCl, followed by a time dependent significant regrowth of C. albicans, but with inter-strain variability. In contrast to NaOCl, there was a continuous reduction in viability after EDTA treatment. Moreover, EDTA significantly inhibited regrowth after NaOCl treatment, though viable cells were still observed.<br><br>CONCLUSIONS: Our results indicate that different C. albicans biofilm phenotypes grown in a non-complex surface topography have the potential to differentially tolerate standard endodontic irrigation protocols. This is the first study to report a strain dependent impact on efficacy of endodontic irrigants. Its suggested that within the complex topography of the root canal, a more difficult antimicrobial challenge, that existing endodontic irrigant regimens permit cells to regrow and drive secondary infections.},
}
@article {pmid31669377,
year = {2019},
author = {Cockeran, R and Dix-Peek, T and Dickens, C and Steel, HC and Anderson, R and Feldman, C},
title = {Biofilm formation and induction of stress response genes is a common response of several serotypes of the pneumococcus to cigarette smoke condensate.},
journal = {The Journal of infection},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jinf.2019.10.014},
pmid = {31669377},
issn = {1532-2742},
abstract = {OBJECTIVES: Exposure to cigarette smoke impacts on the virulence of Streptococcus pneumoniae (pneumococcus) by mechanisms including induction of biofilm formation. Most studies, however, have focused on individual strains of the pneumococcus. Accordingly, the current study has investigated the commonality of the pneumococcal stress response to cigarette smoke condensate (CSC), using five different strains of the pathogen.<br><br>METHODS: Following exposure to CSC at final concentrations of 80 and 160 µg mL-1 during a 16 h incubation period, biofilm formation was measured using a crystal violet-based spectrophotometric procedure. Expression of stress genes seemingly linked to biofilm formation viz. hk11 and rr11 [histidine kinase and response regulator of the two-component regulatory system 11 (TCS11) respectively], cat eff (cation efflux system protein), abc (ATP-binding component of an ATP-binding cassette transporter) and 2005-hyp (hypothetical gene) was measured by sequential extraction of RNA, cDNA synthesis and real-time qPCR.<br><br>RESULTS: Exposure of all five strains of the pneumococcus to CSC, resulted in significant biofilm formation, as well as induction of all five test stress genes.<br><br>CONCLUSIONS: Augmentation of induction of selective stress genes and biofilm formation are common, possibly linked, responses of various serotypes of the pneumococcus to CSC, favouring both persistence of the pathogen and decreased efficacy of antibiotics.},
}
@article {pmid31667388,
year = {2019},
author = {Torres, G and Vargas, K and Sánchez-Jiménez, M and Reyes-Velez, J and Olivera-Angel, M},
title = {Genotypic and phenotypic characterization of biofilm production by Staphylococcus aureus strains isolated from bovine intramammary infections in Colombian dairy farms.},
journal = {Heliyon},
volume = {5},
number = {10},
pages = {e02535},
pmid = {31667388},
issn = {2405-8440},
abstract = {The ability of Staphylococcus aureus to form biofilms is an important virulence factor because this has been associated with persistent bovine intramammary infections. Different mechanisms of biofilm formation have been described in S. aureus; however, the process has been found to be mainly driven by the ica and bap genes. The presence of the ica and bap genes, as well as the biofilm formation in vitro were evaluated in 229 S. aureus strains isolated from bovine milk collected from different regions of Department of Antioquia, Colombia. Three different genotypes grouped into three separate clusters were identified from in vitro assays. Genotype 1 (ica positive and bap negative) was the most prevalent (78.17%), followed by genotype 2 (ica and bap positive) (12.66%) and genotype 0 (ica and bap negative) (9.17%). Biofilm formation was observed in 81.26% of the strains from which 100% of genotype 2 isolates showed biofilm formation. The biofilms formed by genotype 2 isolates were also found to have the highest optical density (>2.4). These results showed that most of the S. aureus strains were capable of biofilm formation, suggesting the virulence potential particularly in bap-positive strains.},
}
@article {pmid31666981,
year = {2019},
author = {Yung, YP and McGill, SL and Chen, H and Park, H and Carlson, RP and Hanley, L},
title = {Reverse diauxie phenotype in Pseudomonas aeruginosa biofilm revealed by exometabolomics and label-free proteomics.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {31},
pmid = {31666981},
issn = {2055-5008},
abstract = {Microorganisms enhance fitness by prioritizing catabolism of available carbon sources using a process known as carbon catabolite repression (CCR). Planktonically grown Pseudomonas aeruginosa is known to prioritize the consumption of organic acids including lactic acid over catabolism of glucose using a CCR strategy termed &quot;reverse diauxie.&quot; P. aeruginosa is an opportunistic pathogen with well-documented biofilm phenotypes that are distinct from its planktonic phenotypes. Reverse diauxie has been described in planktonic cultures, but it has not been documented explicitly in P. aeruginosa biofilms. Here a combination of exometabolomics and label-free proteomics was used to analyze planktonic and biofilm phenotypes for reverse diauxie. P. aeruginosa biofilm cultures preferentially consumed lactic acid over glucose, and in addition, the cultures catabolized the substrates completely and did not exhibit the acetate secreting &quot;overflow&quot; metabolism that is typical of many model microorganisms. The biofilm phenotype was enabled by changes in protein abundances, including lactate dehydrogenase, fumarate hydratase, GTP cyclohydrolase, L-ornithine N(5)-monooxygenase, and superoxide dismutase. These results are noteworthy because reverse diauxie-mediated catabolism of organic acids necessitates a terminal electron acceptor like O2, which is typically in low supply in biofilms due to diffusion limitation. Label-free proteomics identified dozens of proteins associated with biofilm formation including 16 that have not been previously reported, highlighting both the advantages of the methodology utilized here and the complexity of the proteomic adaptation for P. aeruginosa biofilms. Documenting the reverse diauxic phenotype in P. aeruginosa biofilms is foundational for understanding cellular nutrient and energy fluxes, which ultimately control growth and virulence.},
}
@article {pmid31665633,
year = {2019},
author = {Xu, Z and Mandic-Mulec, I and Zhang, H and Liu, Y and Sun, X and Feng, H and Xun, W and Zhang, N and Shen, Q and Zhang, R},
title = {Antibiotic Bacillomycin D Affects Iron Acquisition and Biofilm Formation in Bacillus velezensis through a Btr-Mediated FeuABC-Dependent Pathway.},
journal = {Cell reports},
volume = {29},
number = {5},
pages = {1192-1202.e5},
doi = {10.1016/j.celrep.2019.09.061},
pmid = {31665633},
issn = {2211-1247},
abstract = {Bacillus spp. produce a wide range of secondary metabolites, including antibiotics, which have been well studied for their antibacterial properties but less so as signaling molecules. Previous results indicated that the lipopeptide bacillomycin D is a signal that promotes biofilm development of Bacillus velezensis SQR9. However, the mechanism behind this signaling is still unknown. Here, we show that bacillomycin D promotes biofilm development by promoting the acquisition of iron. Bacillomycin D promotes the transcription of the iron ABC transporter FeuABC by binding to its transcription factor, Btr. These actions increase intracellular iron concentration and activate the KinB-Spo0A-SinI-SinR-dependent synthesis of biofilm matrix components. We demonstrate that this strategy is beneficial for biofilm development and competition with the Pseudomonas fluorescens PF-5. Our results unravel an antibiotic-dependent signaling mechanism that links iron acquisition to biofilm development and ecological competition.},
}
@article {pmid31663721,
year = {2019},
author = {Zhong, N and Wu, Y and Wang, Z and Chang, H and Zhong, D and Xu, Y and Hu, X and Huang, L},
title = {Monitoring Microalgal Biofilm Growth and Phenol Degradation with Fiber-Optic Sensors.},
journal = {Analytical chemistry},
volume = {91},
number = {23},
pages = {15155-15162},
doi = {10.1021/acs.analchem.9b03923},
pmid = {31663721},
issn = {1520-6882},
abstract = {Simple D-type plastic optical fiber (POF) probes (i.e., sensor, reference, and photochemical probes) were created to accurately monitor the progression and phenol degradation of a Chlorella vulgaris biofilm. The sensor and reference probes were used to monitor the biofilm growth (thickness). The sensor probe, which consisted of a D-shaped POF and Canada balsam doped with GeO2 (CBG) coating, was developed to monitor the biofilm growth and change in the liquid-phase composition and its concentration inside the biofilm. The reference probe, which comprised a D-shaped POF, CBG coating, and glass fiber membrane (to separate the liquids from Chlorella vulgaris), was used to measure the response to changes in the liquid phase. A model was developed to demonstrate the accurate measurement of the biofilm thickness. The photochemical POF probe was coupled with a high-permselectivity phenol polymer membrane to monitor the phenol concentration and analyze the degradation time of 50 mg/L phenol with microalgal biofilms. A fixed relationship was obtained between the biofilm sensor output information and biofilm thickness for a biofilm thickness range of 0-290 μm with a periodic supply of 50 mg/L phenol solution. The highest phenol degradation rate occurred at a biofilm thickness of 191-222 μm. The proposed system can be used to investigate microalgal biomass and can provide a promising avenue for research on renewable resources and pollutant degradation.},
}
@article {pmid31663364,
year = {2019},
author = {Tsiaprazi-Stamou, A and Monfort, IY and Romani, AM and Bakalis, S and Gkatzionis, K},
title = {The synergistic effect of enzymatic detergents on biofilm cleaning from different surfaces.},
journal = {Biofouling},
volume = {35},
number = {8},
pages = {883-899},
doi = {10.1080/08927014.2019.1666108},
pmid = {31663364},
issn = {1029-2454},
abstract = {Biofilm growth is a significant source of contamination in the food industry. Enzymes are considered green countermeasures against biofilm formation in the food industry owing to their biodegradability and low toxicity. In this study, the synergistic effect of enzymes was studied against biofilm cleaning from hard surfaces. A mixed-microbial sample was sourced from a meat packaging line and biofilms were grown under high shear conditions on stainless steel and polyethylene surfaces. A model cleaning-in-place (CIP) parallel-plate flow chamber was used for firstly, the enzymatic cleaning and secondly, a disinfection step. The cleaning effectiveness was evaluated in response to different formulations containing non-foaming commercial surfactants among with amylase, protease and lipase at neutral pH. The formulation combining all three enzymes was the most effective, showing a synergy essential for the deformation of biofilm structure and consequently better disinfection of both material surfaces.},
}
@article {pmid31659674,
year = {2019},
author = {Abbas, AF and Al-Saadi, AGM and Alkhudhairy, MK},
title = {Biofilm Formation and Virulence Determinants of Klebsiella oxytoca Clinical Isolates from Patients with Colorectal Cancer.},
journal = {Journal of gastrointestinal cancer},
volume = {},
number = {},
pages = {},
doi = {10.1007/s12029-019-00317-7},
pmid = {31659674},
issn = {1941-6636},
abstract = {OBJECTIVE: Biofilm formation has made the therapy of bacterial infections more difficult. The objective our study was assessment of pan-drug-resistant (PDR) Klebsiella oxytoca pathogenicity and virulence factors causing AAHC in patients with colorectal cancer (CRC).<br><br>MATERIALS AND METHODS: Among a total of 300 healthy and 300 patients with antibiotic-associated hemorrhagic colitis (AAHC) and CRC, 200 K. oxytoca were identified during May 2015-January 2019. The virulence properties and biofilm formation among the isolates were investigated by phenotypic, PCR, and real-time PCR (RT-qPCR) techniques.<br><br>RESULTS: The blaCTX-M1 (20%), blaSHV (11%), blaTEM1 (33%), and AmpC encoding CIT (2%) ESBL genes, carbapenemase-encoding genes blaIM (4%) and blaOXA-48 (2%), and colistin-resistant mcr-1 gene (2.5%) were detected. The virulence-encoding genes including fimA (80%), pilQ (100%), matB (100%), mrkA (80%), and npsB (100%) were amplified. Therefore, PDR K. oxytoca containing adhesins and toxin-encoding genes with ability of biofilm formation causing AAHC and CRC were isolated. There was a significant difference between healthy and patients with CRC regarding the presence of K. oxytoca (p = 00.221).<br><br>CONCLUSION: Bacterial enteric pathogens possibly play a role in CRC. Biofilm formation by K. oxytoca strains prevents the efficient infection elimination; therefore, rapid identification and control measure are chief requirements. Additionally, more investigations are necessary with this regard.},
}
@article {pmid31659297,
year = {2019},
author = {Díaz-Pascual, F and Hartmann, R and Lempp, M and Vidakovic, L and Song, B and Jeckel, H and Thormann, KM and Yildiz, FH and Dunkel, J and Link, H and Nadell, CD and Drescher, K},
title = {Breakdown of Vibrio cholerae biofilm architecture induced by antibiotics disrupts community barrier function.},
journal = {Nature microbiology},
volume = {4},
number = {12},
pages = {2136-2145},
pmid = {31659297},
issn = {2058-5276},
support = {P20 GM113132/GM/NIGMS NIH HHS/United States ; SFB 987//Deutsche Forschungsgemeinschaft (German Research Foundation)/ ; MCB 1817342//National Science Foundation (NSF)/ ; 716734//EC | EU Framework Programme for Research and Innovation H2020 | H2020 Priority Excellent Science | H2020 European Research Council (H2020 Excellent Science - European Research Council)/ ; GM113132//U.S. Department of Health &amp; Human Services | National Institutes of Health (NIH)/ ; 716734/ERC_/European Research Council/International ; CDA00084/2015-C//Human Frontier Science Program (HFSP)/ ; STANTO15RO//Cystic Fibrosis Foundation (CF Foundation)/ ; },
abstract = {Bacterial cells in nature are frequently exposed to changes in their chemical environment1,2. The response mechanisms of isolated cells to such stimuli have been investigated in great detail. By contrast, little is known about the emergent multicellular responses to environmental changes, such as antibiotic exposure3-7, which may hold the key to understanding the structure and functions of the most common type of bacterial communities: biofilms. Here, by monitoring all individual cells in Vibrio cholerae biofilms during exposure to antibiotics that are commonly administered for cholera infections, we found that translational inhibitors cause strong effects on cell size and shape, as well as biofilm architectural properties. We identified that single-cell-level responses result from the metabolic consequences of inhibition of protein synthesis and that the community-level responses result from an interplay of matrix composition, matrix dissociation and mechanical interactions between cells. We further observed that the antibiotic-induced changes in biofilm architecture have substantial effects on biofilm population dynamics and community assembly by enabling invasion of biofilms by bacteriophages and intruder cells of different species. These mechanistic causes and ecological consequences of biofilm exposure to antibiotics are an important step towards understanding collective bacterial responses to environmental changes, with implications for the effects of antimicrobial therapy on the ecological succession of biofilm communities.},
}
@article {pmid31658838,
year = {2019},
author = {Flores-Treviño, S and Bocanegra-Ibarias, P and Camacho-Ortiz, A and Morfín-Otero, R and Salazar-Sesatty, HA and Garza-González, E},
title = {Stenotrophomonas maltophilia biofilm: its role in infectious diseases.},
journal = {Expert review of anti-infective therapy},
volume = {17},
number = {11},
pages = {877-893},
doi = {10.1080/14787210.2019.1685875},
pmid = {31658838},
issn = {1744-8336},
abstract = {Introduction: Infections caused by the opportunistic Stenotrophomonas maltophilia pathogen in immunocompromised patients are complicated to treat due to antibiotic resistance and the ability of the bacteria to produce biofilm.Areas covered: A MEDLINE/PubMed search was performed of available literature to describe the role of biofilm produced by S. maltophilia in the diseases it causes, including biofilm-influencing factors, the biofilm forming process and composition. The antimicrobial resistance due to S. maltophilia biofilm production and current antibiofilm strategies is also included.Expert opinion: Through the production of biofilm, S. maltophilia strains can easily adhere to the surfaces in hospital settings and aid in its transmission. The biofilm can also cause antibiotic tolerance rendering some of the therapeutic options ineffective, causing setbacks in the selection of an appropriate treatment. Conventional susceptibility tests do not yet offer therapeutic guidelines to treat biofilm-associated infections. Current S. maltophilia biofilm control strategies include natural and synthetic compounds, chelating agents, and commonly prescribed antibiotics. As biofilm age and matrix composition affect the level of antibiotic tolerance, their characterization should be included in biofilm susceptibility testing, in addition to molecular and proteomic analyzes. As for now, several commonly recommended antibiotics can be used to treat biofilm-related S. maltophilia infections.},
}
@article {pmid31658638,
year = {2019},
author = {Thakur, D and Govindaraju, S and Yun, K and Noh, JS},
title = {The Synergistic Effect of Zinc Ferrite Nanoparticles Uniformly Deposited on Silver Nanowires for the Biofilm Inhibition of Candida albicans.},
journal = {Nanomaterials (Basel, Switzerland)},
volume = {9},
number = {10},
pages = {},
pmid = {31658638},
issn = {2079-4991},
support = {2019R1A2C1008746//National Research Foundation of Korea/ ; 2016R1D1A1B03932515//National Research Foundation of Korea/ ; },
abstract = {Near-monodisperse zinc ferrite nanoparticles (ZnFe2O4 NPs) are synthesized by a co-precipitation method and deposited on the surface of silver nanowires (AgNWs), employing a stepwise solution method. The resulting hybrid nanostructures (ZnFe2O4@AgNWs) show a thin and uniform layer of ZnFe2O4 NPs at an optimum weight ratio of 1:6 between the two component nanostructures. The hybrid nanostructures retain the high crystal quality and phase purity of their constituents. It is demonstrated that the ZnFe2O4@AgNWs hybrid nanostructures are effective at inhibiting the biofilm formation of Candida albicans cells. The biofilm inhibition activity of the hybrid nanostructures is estimated to be more than 50% at a low concentration of 100 µg/mL from both crystal violet assay and XTT assay, which are more than 8-fold higher than those of pure AgNWs and ZnFe2O4 NPs. This greatly enhanced biofilm inhibition activity is attributed to the ZnFe2O4 NPs-carrying membrane penetration by AgNWs and the subsequent interaction between Candida cells and ZnFe2O4 NPs. These results indicate that the ZnFe2O4@AgNWs hybrid nanostructures have great potential as a new type of novel antibiofilm agent.},
}
@article {pmid31656524,
year = {2019},
author = {Betesho Babrud, R and Kasra Kermanshahi, R and Motamedi Sede, F and Moosavinejad, SZ},
title = {The effect of Lactobacillus reuteri cell free supernatant on growth and biofilm formation of Paenibacillus larvae.},
journal = {Iranian journal of veterinary research},
volume = {20},
number = {3},
pages = {192-198},
pmid = {31656524},
issn = {1728-1997},
abstract = {Background: Paenibacillus larvae is the etiological agent of American foulbrood (AFB) disease, the most lethal disease in honeybee (Apis mellifera) larvae.<br><br>Aims: The aim of the present work was to study the antimicrobial effect of cell free supernatant (CFS) of probiotics on an Iranian isolate's biofilm formation.<br><br>Methods: A local strain was identified by 16S rRNA sequencing. The antibacterial effect of some probiotics was evaluated through drop plate method, minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC) and time-kill assay. The biofilm formation ability of P. larvae and the inhibition of biofilm formation by CFS were studied by microplate and scanning electron microscopy (SEM). The nature of the secondary metabolites in CFS was examined by microscale optical density assay (MODA).<br><br>Results: Alignment of the results of P. larvae KB10 (GenBank accession number MH000685.1) 16S rRNA with the database revealed more than 97% identity with P. larvae. The most antibacterial effect was observed in the CFS of Lactobacillus reuteri ATCC23272 with 12.75 ± 3.2 mm for zone of inhibition (ZOI) at 1000 µL/ml for MIC and MBC. Time-kill assay revealed that CFS eliminated 1.5 × 108 CFU/ml P. larvae KB10 at 2 h of exposure. Microtitre plate and SEM results revealed that CFS (at sub-MIC concentration) was able to inhibit biofilm formation by P. larvae. The results of MODA assay showed that antimicrobial activity were related to the production of organic acids.<br><br>Conclusion: Cell free supernatant from L. reuteri ATCC 23272 had inhibitory effects on P. larvae KB10 growth and biofilm production due to its acidic nature. The obtained results can be used for antibiotic substitution in AFB control and treatment.},
}
@article {pmid31656155,
year = {2019},
author = {Ielapi, N and Nicoletti, E and Lorè, C and Guasticchi, G and Avenoso, T and Barbetta, A and de Franciscis, S and Andreucci, M and Sapienza, P and Serra, R},
title = {The Role of Biofilm In Central Venous Catheter Related Bloodstream Infections: Evidence Based Nursing And Review of The Literature.},
journal = {Reviews on recent clinical trials},
volume = {},
number = {},
pages = {},
doi = {10.2174/1574887114666191018144739},
pmid = {31656155},
issn = {1876-1038},
abstract = {BACKGROUND: Biofilm is a fundamental component in the pathogenesis of infections related to the use of the central venous catheter (CVC,) which can represent an important health issue in every day practice of nursing and medical staff.<br><br>OBJECTIVE: The objective of the following review is to analyze the components of biofilm and thier role in catheter-related infection determinism in an evidence-based nursing perspective in such a way as to give health professionals useful suggestions in the prevention and management of these complications.<br><br>METHODS: The following databases were consulted for the bibliographic search: Medline, Scopus, Science Direct. Biofilm can be the cause of CVC extraction and can lead to serious haematogenic infectious complications that can increase the morbidity and mortality of affected patients.<br><br>RESULTS: Updated pathophysiologic knowledge of biofilm formation and appropriate diagnostic methodology are pivotal in understanding and detecting CVC-related infections. Lock therapy appears to be a useful, preventive and therapeutic aid in the management of CVC-related infections. New therapies attempting to stop bacterial adhesion on the materials used could represent new frontiers for the prevention of CVC-related infections.<br><br>CONCLUSION: The correct evidence-based nursing methods, based on the use of Guidelines, provides the opportunity to minimize the risks of infection through the implementation of a series of preventive measures both during the CVC positioning phase and in the subsequent phase, meaningly during device management which is performed by medical and nursing staff.},
}
@article {pmid31655088,
year = {2019},
author = {Narmani, A and Teponno, RB and Helaly, SE and Arzanlou, M and Stadler, M},
title = {Cytotoxic, anti-biofilm and antimicrobial polyketides from the plant associated fungus Chaetosphaeronema achilleae.},
journal = {Fitoterapia},
volume = {139},
number = {},
pages = {104390},
doi = {10.1016/j.fitote.2019.104390},
pmid = {31655088},
issn = {1873-6971},
mesh = {Anti-Bacterial Agents/isolation &amp; purification/*pharmacology ; Antineoplastic Agents/isolation &amp; purification/*pharmacology ; Ascomycota/*chemistry ; Biofilms/*drug effects ; Humans ; Iran ; MCF-7 Cells ; Microbial Sensitivity Tests ; Molecular Structure ; Staphylococcus aureus/drug effects ; Taxus/*microbiology ; },
abstract = {From extracts of the plant associated fungus Chaetosphaeronema achilleae collected in Iran, a previously unreported isoindolinone named chaetosisoindolinone (1) and a previously undescribed indanone named chaetosindanone (2) were isolated in addition to five known metabolites, 2-(2-acetyl-3,5-dihydroxyphenyl) acetic acid (3), vulculic acid (4), 2-(2-acetyl-3-hydroxy-5-methoxyphenyl)acetic acid (5), curvulin (6), and curvulol (7). Their structures were elucidated on the basis of extensive spectroscopic analysis and high-resolution mass spectrometry. The isolated compounds were tested for their antimicrobial, anti-biofilm, and nematicidal activities. Compound 2 exhibited cytotoxicity against the human breast adenocarcinoma MCF-7 cells with an IC50 value of 1.5 μg/mL. Furthermore, compounds 4 and 7 almost completely inhibited biofilm formation in Staphylococcus aureus at 256 μg/mL. Weak antimicrobial activities were also observed for some of the isolated compounds against Mucor hiemalis, Rhodoturula glutinis, Chromobacterium violaceum, and Staphylococcus aureus.},
}
@article {pmid31654510,
year = {2019},
author = {Singla, RK and Dubey, AK},
title = {Molecules and Metabolites from Natural Products as Inhibitors of Biofilm in Candida spp. pathogens.},
journal = {Current topics in medicinal chemistry},
volume = {19},
number = {28},
pages = {2567-2578},
doi = {10.2174/1568026619666191025154834},
pmid = {31654510},
issn = {1873-4294},
abstract = {BACKGROUND: Biofilm is a critical virulence factor associated with the strains of Candida spp. pathogens as it confers significant resistance to the pathogen against antifungal drugs.<br><br>METHODS: A systematic review of the literature was undertaken by focusing on natural products, which have been reported to inhibit biofilms produced by Candida spp. The databases explored were from PubMed and Google Scholar. The abstracts and full text of the manuscripts from the literature were analyzed and included if found significant.<br><br>RESULTS: Medicinal plants from the order Lamiales, Apiales, Asterales, Myrtales, Sapindales, Acorales, Poales and Laurales were reported to inhibit the biofilms formed by Candida spp. From the microbiological sources, lactobacilli, Streptomyces chrestomyceticus and Streptococcus thermophilus B had shown the strong biofilm inhibition potential. Further, the diverse nature of the compounds from classes like terpenoids, phenylpropanoid, alkaloids, flavonoids, polyphenol, naphthoquinone and saponin was found to be significant in inhibiting the biofilm of Candida spp.<br><br>CONCLUSION: Natural products from both plant and microbial origins have proven themselves as a goldmine for isolating the potential biofilm inhibitors with a specific or multi-locus mechanism of action. Structural and functional characterization of the bioactive molecules from active extracts should be the next line of approach along with the thorough exploration of the mechanism of action for the already identified bioactive molecules.},
}
@article {pmid31653277,
year = {2019},
author = {Gholami, SA and Goli, HR and Haghshenas, MR and Mirzaei, B},
title = {Evaluation of polysaccharide intercellular adhesion (PIA) and glycerol teichoic acid (Gly-TA) arisen antibodies to prevention of biofilm formation in Staphylococcus aureus and Staphylococcus epidermidis strains.},
journal = {BMC research notes},
volume = {12},
number = {1},
pages = {691},
pmid = {31653277},
issn = {1756-0500},
abstract = {OBJECTIVE: Staphylococcus aureus and S. epidermidis as opportunistic pathogens, notable for their frequency and severity of infections are recognized as the most usual reasons for medical device-associated infections that strike hospitalized patients and also immunocompromised individuals. In this study, the polysaccharide intercellular adhesion (PIA) and Glycerol teichoic acid) Gly-TA) as two major macromolecules in the biofilm formation process were purified under the native condition and their structure was analyzed by using colorimetric assays and Fourier Transform Infrared spectroscopy (FTIR). Afterward, the immune response of macromolecules and the mixture of them were assessed by measuring total IgG titers. Subsequently, biofilm inhibitory effects of raising antibodies to biofilm former S. aureus and S. epidermidis were evaluated.<br><br>RESULTS: Obtained data were shown a significant rise in levels of antibodies in immunized mice with mentioned antibodies in comparison with the control group. According to the obtained findings, mentioned antibodies could eliminate S. aureus and S. epidermidis biofilm formation in vitro assays. This survey confirms the proposal that immunization of mice with a mixture of Gly-TA and PIA vaccine could be secure and protected against S. epidermidis and S. aureus infection.},
}
@article {pmid31652836,
year = {2019},
author = {Choi, JS and Lee, JW and Shin, UC and Lee, MW and Kim, DJ and Kim, SW},
title = {Inhibitory Activity of Silver Nanoparticles Synthesized Using Lycopersicon Esculentum against Biofilm Formation in Candida Species.},
journal = {Nanomaterials (Basel, Switzerland)},
volume = {9},
number = {11},
pages = {},
pmid = {31652836},
issn = {2079-4991},
support = {P0006675//Ministry of Trade, Industry and Energy(MOTIE) and Korea Institute for Advancement of Technology(KIAT)/ ; },
abstract = {This paper investigated the antifungal and antibiofilm activity of silver nanoparticles synthesized with Lycopersicon esculentum extracts against Candida species. Lycopersicon esculentum extracts obtained by homogenization were mixed with silver nitrate to synthesize silver nanoparticles. Analysis of the particle characteristics by UV-Vis spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FT-IR) confirmed that the Lycopersicon esculentum extracts effectively served as reductants and capping agents. Minimum inhibitory concentration (MIC) tests were conducted to confirm antifungal activity against Candida species. In all the tested species, the silver nanoparticles inhibited the growth of Candida. Moreover, the SEM images of Candida species treated with silver nanoparticles synthesized using natural extracts of Lycopersicon esculentum showed that silver nanoparticles adhered to the surface of Candida, which induced pore formation in the membranes and prevented their normal growth. Ultimately, these abnormal forms of Candida were thought to be less able to form biofilms than normal Candida. The antifungal and antibiofilm activities of silver nanoparticles against Candida are expected to be utilized in various fields and contribute in particular to developments in nanomedicine.},
}
@article {pmid31652575,
year = {2019},
author = {Maletskyi, Z and Zigta, DK and Kulesha, O and Ratnaweera, H},
title = {Chemical Enhancement for Retrofitting Moving Bed Biofilm and Integrated Fixed Film Activated Sludge Systems into Membrane Bioreactors.},
journal = {Membranes},
volume = {9},
number = {10},
pages = {},
pmid = {31652575},
issn = {2077-0375},
abstract = {Positive effects of retrofitting MBBR and IFAS systems into MBRs can be exploited by introducing chemical enhancement applying coagulants in the membrane separation step. The current study reports basic principles of chemical enhancement with aluminium sulphate coagulant in biofilm-MBR (Bf-MBR) based on results of total recycle tests performed at different dosages of the chemical enhancer and properties characterization of filtrates, supernatants and sediments. It demonstrates a possibility to achieve lower membrane fouling rates with dosing of aluminium sulphate coagulant into MBBR and IFAS mixed liquors by extending operational cycles by 20 and 80 time respectively as well as increasing operating permeability of membrane separation by 1.3 times for IFAS. It has been found that charge neutralization is the dominating mechanism of aluminium sulphate action as a chemical enhancer in Bf-MBR, however, properties of the membrane surface influencing charge repulsion of foulants should be considered together with the secondary ability of the coagulant to improve consolidation of sediments.},
}
@article {pmid31652188,
year = {2019},
author = {Ferlic, PW and Liebensteiner, M and Nogler, M and Weinberg, A and Kühn, KD and Coraça-Huber, DC},
title = {Increased Staphylococcus aureus biofilm formation on biodegradable PHB-implants compared to conventional orthopedic implants: an in vitro analysis.},
journal = {Journal of orthopaedic trauma},
volume = {},
number = {},
pages = {},
doi = {10.1097/BOT.0000000000001674},
pmid = {31652188},
issn = {1531-2291},
abstract = {OBJECTIVE: To compare the biofilm formation on a biodegradable material, poly(3-hydroxybutyrate) (PHB), to that on conventional titanium (Ti) and steel (St) implant material.<br><br>METHODS: Pins made of the different materials were incubated in Müller-Hinton broth inoculated with 2 x 10 CFU mL-1 of S. aureus for 2 and 7 days and then sonicated for the disruption of the biofilms. Colony forming units (CFU) were counted to quantify the number of bacteria in the biofilm and the cell proliferation assay XTT was used to evaluate their metabolic activity. Scanning electron microscopy (SEM) visualized the structure of the biofilm.<br><br>RESULTS: We found a significantly higher metabolic activity and CFU count in the biofilm of PHB pins compared to St and Ti (ANOVA p<0.0001). SEM revealed structured biofilms on PHB pins already after 2 days of incubation, which was not observed on the other tested implants.<br><br>CONCLUSION: PHB implants seem to provide an environment that advantages the formation of biofilms of S. aureus, a common pathogen in implant related infections. The amount of biofilm is higher on PHB compared to conventionally used orthopedic titanium and steel implants. To overcome the potential risk of surgical site infections linked to the clinical use of PHB implants, possible modifications of the material, increasing its antibacterial properties, need to be further investigated.},
}
@article {pmid31651349,
year = {2019},
author = {Lee, S and Hwang, J and Kim, J and Lee, J and Kim, HC and Rhim, H and Han, JI},
title = {Biofilm production of coagulase-negative staphylococci isolated from rescued wild animals in the Republic of Korea.},
journal = {Acta veterinaria Scandinavica},
volume = {61},
number = {1},
pages = {50},
pmid = {31651349},
issn = {1751-0147},
support = {2016R1D1A3B03932480//National Research Foundation of Korea/ ; 2016000210002//ministry of envirionment korea/ ; },
abstract = {Biofilm production is a well-known causative factor of catheter- and medical device-related sepsis. Its high prevalence in coagulase-negative staphylococci (CoNS) has recently been reported. Information on biofilm production in CoNS isolated from wild animals is lacking. Herein, we studied the biofilm formation capabilities of CoNS isolated from rescued wild animals in the Republic of Korea. Swab samples were collected from the conjunctiva, nasal cavity, perianal area, and rectum for mammals while the sampling was done from the conjunctiva, oral mucosa, pericloacal area, and cloaca for birds. Isolation of CoNS was based on morphological and biochemical analyses along with molecular typing. Biofilm production was analyzed using 96-well plate based quantitative adherence assays. The studies demonstrated that CoNS of mammalian origin have higher biofilm-producing ability (70.4%) than the isolates from birds (62.5%). In particular, all methicillin-resistant (MR) CoNS isolated from mammals were capable of biofilm formation while only 63.3% of MR CoNS isolated from birds could produce biofilms. The MR CoNS isolated from mammals also had a significantly higher ability to form biofilms (100%) than methicillin susceptible CoNS (60.0%) than those isolates from birds. The findings show that wild animals may act as reservoirs as well as possible transmitters of biofilm-mediated antibiotic resistant genes.},
}
@article {pmid31649642,
year = {2019},
author = {Tan, F and She, P and Zhou, L and Liu, Y and Chen, L and Luo, Z and Wu, Y},
title = {Bactericidal and Anti-biofilm Activity of the Retinoid Compound CD437 Against Enterococcus faecalis.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2301},
pmid = {31649642},
issn = {1664-302X},
abstract = {Enterococcus faecalis (E. faecalis), a biofilm-forming pathogen, causes nosocomial infections. In recent years, drug resistance by enterococci has become increasingly severe due to widespread antibiotic abuse. Therefore, novel antibacterial agents are urgently needed. In this study, the synthetic retinoid compound CD437 was found to have potent bactericidal effect on E. faecalis. In addition, CD437 exhibited synergistic effects when administered in combination with gentamicin and additive effects when combined with ceftriaxone sodium. CD437 also inhibited biofilm formation by E. faecalis and exerted bactericidal effect on mature biofilm. Moreover, CD437 exhibited antibacterial and anti-biofilm effects against Staphylococcus. No bactericidal action of CD437 was observed against the gram-negative bacillus, but Pseudomonas aeruginosa biofilm extracellular polymeric substances (EPS) matrix formation was reduced. Overall, these findings indicate that CD437 has the potential to be developed as a novel antibacterial drug.},
}
@article {pmid31648793,
year = {2019},
author = {Park, JW and An, JS and Lim, WH and Lim, BS and Ahn, SJ},
title = {Microbial changes in biofilms on composite resins with different surface roughness: An in vitro study with a multispecies biofilm model.},
journal = {The Journal of prosthetic dentistry},
volume = {122},
number = {5},
pages = {493.e1-493.e8},
doi = {10.1016/j.prosdent.2019.08.009},
pmid = {31648793},
issn = {1097-6841},
mesh = {Bacterial Adhesion ; Biofilms ; *Composite Resins ; *Streptococcus mutans ; Surface Properties ; },
abstract = {STATEMENT OF PROBLEM: The single-species biofilm method cannot represent the interaction and complex functions of microorganisms associated with oral biofilms.<br><br>PURPOSE: The purpose of this in vitro study was to investigate microbial changes in biofilms on composite resins of varying surface roughness by using a multispecies biofilm model with early-colonizing streptococci, middle colonizer, and late-colonizing gram-negative anaerobes.<br><br>MATERIAL AND METHODS: Composite resin disks were prepared with different roughness: SR180, SR400, SR1500, and SRGlass roughened with 180-, 400-, and 1500-grit silicon carbide paper and glass (control surface without surface roughening). Surface roughness was analyzed by confocal laser scanning and scanning electron microscopy. After multispecies biofilms had been grown on the composite resin surfaces, the adhesion of Streptococcus mutans, Streptococcus sobrinus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and of total bacteria was determined after 1 (T1) and 4 (T2) days. Differences in surface roughness among the 4 groups were tested with 1-way ANOVA. Multifactorial analysis of variance was used to determine the time-related differences in the bacterial composition with respect to surface roughness (α=.05).<br><br>RESULTS: The order of SR, from highest to lowest, was SR180 (1.45 ±0.11 μm), SR400 (0.62 ±0.05 μm), SR1500 (0.35 ±0.02 μm), and SRGlass (0.15 ±0.01 μm) (SR180>SR400>SR1500>SRGlass, P<.001). Increased surface roughness was not proportional to bacterial adhesion. Significant differences in the adhesion of total bacteria was only found between SRGlass and SR180 (SR180>SRGlass, P=.029). The adhesion of S. mutans and S. sobrinus to SR180 and SR400 was higher than that to SRGlass (SR180=SR400>SRGlass; S. mutans, P=.003; S. sobrinus, P=.002). However, the adhesion of A. actinomycetemcomitans and P. gingivalis to composite resin was not significantly influenced by surface roughness. Adhesion of total bacteria, S. mutans, and S. sobrinus increased from T1 to T2 (T1<T2, P<.001), whereas the adhesion of periodontal pathogens decreased from T1 to T2 (T1>T2; A. actinomycetemcomitans, P<.001; P. gingivalis, P=.013).<br><br>CONCLUSIONS: Decreased adhesion of cariogenic streptococci and total bacteria was observed at surface roughness values of around 0.15 μm. Periodic finishing of surface roughness should be considered to minimize the adhesion of cariogenic streptococci to composite resin surfaces.},
}
@article {pmid31647407,
year = {2019},
author = {Sugathan, S and Mandal, J},
title = {An invitro experimental study of the effect of fosfomycin in combination with amikacin, ciprofloxacin or meropenem on biofilm formation by multidrug-resistant urinary isolates of Escherichia coli.},
journal = {Journal of medical microbiology},
volume = {68},
number = {12},
pages = {1699-1706},
doi = {10.1099/jmm.0.001061},
pmid = {31647407},
issn = {1473-5644},
mesh = {Amikacin/administration &amp; dosage/pharmacology ; Anti-Bacterial Agents/*pharmacology ; Biofilms/*drug effects ; Ciprofloxacin/administration &amp; dosage/pharmacology ; Drug Synergism ; Escherichia coli/drug effects/*physiology ; Fosfomycin/administration &amp; dosage/pharmacology ; Humans ; Meropenem/administration &amp; dosage/pharmacology ; Microbial Sensitivity Tests ; Urinary Tract Infections/*microbiology ; },
abstract = {Background. This study was conducted to understand the effect of fosfomycin in combination with amikacin, ciprofloxacin or meropenem on biofilm formation by multidrug-resistant urinary isolates of Escherichia coli.Methods. Fifty urinary tract multidrug-resistant E. coli isolates that were known biofilm producers were studied. The MIC was determined using the agar dilution method for amikacin, ciprofloxacin, meropenem and fosfomycin. The fractional inhibitory concentration was determined for the combination of antibiotics followed by a time-kill assay. A tissue culture plate method was used to study the effect of the combination of antibiotics on biofilm formation.Results. The MICs of the isolates tested ranged from 0.25 to 32 µg ml-1 for fosfomycin, 1 to 1024 µg ml-1 for ciprofloxacin, 4 to 1024 µg ml-1 for amikacin, and 0.25 to 512 µg ml-1 for meropenem. The combination of fosfomycin with meropenem showed 68 % synergy, fosfomycin with amikacin 58 % synergy and fosfomycin with ciprofloxacin 6 % synergy. The combination also reduced the MIC of each antibiotic and none showed an antagonistic effect. Biofilm inhibition was best observed with the combination of fosfomycin with meropenem.Conclusion. The combination of fosfomycin with amikacin and fosfomycin with meropenem yielded a high percentage of synergy alongside an increased capacity to reduce biofilm formation when compared to combination with ciprofloxacin against multidrug-resistant E. coli. Fosfomycin in combination with other classes of antimicrobial agents has potential beneficial effects.},
}
@article {pmid31646898,
year = {2019},
author = {Alvim, DCSS and Ferreira, AFM and Leal, MA and Oliveira, LMA and Botelho, AMN and Botelho, ACN and Figueiredo, AMS and Fracalanzza, SEL and Teixeira, LM and Pinto, TCA},
title = {Biofilm production and distribution of pilus variants among Streptococcus agalactiae isolated from human and animal sources.},
journal = {Biofouling},
volume = {35},
number = {8},
pages = {938-944},
doi = {10.1080/08927014.2019.1678592},
pmid = {31646898},
issn = {1029-2454},
abstract = {Streptococcus agalactiae (group B Streptococcus, GBS) is a major pathogen in humans and animals. Pili and biofilm may be important virulence factors in this bacterial species. Here, biofilm production and the distribution of pilus variants among 134 GBS isolates from human and animal sources were evaluated. Biofilm production was significantly enhanced in 1% glucose-supplemented medium (p < 0.05). Using this medium, most GBS strains were strong biofilm producers. Biomass was mainly composed of proteins, followed by extracellular DNA, while polysaccharides represented a minor portion. All GBS strains presented at least one pilus variant. PI-2a was the most common among human GBS while PI-2b was the most common among animal isolates. Human GBS harboring PI-2b and animal GBS harboring PI-2a presented significantly reduced biofilm production (p = 0.0033). In conclusion, strong biofilm production seems to be a common characteristic in GBS, and association of the clinical source with the pilus variant may be crucial for this.},
}
@article {pmid31646225,
year = {2019},
author = {Saigal, and Irfan, M and Khan, P and Abid, M and Khan, MM},
title = {Design, Synthesis, and Biological Evaluation of Novel Fused Spiro-4H-Pyran Derivatives as Bacterial Biofilm Disruptor.},
journal = {ACS omega},
volume = {4},
number = {16},
pages = {16794-16807},
pmid = {31646225},
issn = {2470-1343},
abstract = {This study aims to synthesize novel fused spiro-4H-pyran derivatives under green conditions to develop agents having antimicrobial activity. The synthesized compounds were initially screened for in vitro antibacterial activity against two Gram-positive and three Gram-negative bacterial strains, and all the compounds exhibited moderate to potent antibacterial activity. However, compound 4l showed significant inhibition toward all the bacterial strains, particularly against Streptococcus pneumoniae and Escherichia coli with minimum inhibitory concentration values of 125 μg/mL for each. The toxicity studies of selected compounds (4c, 4e, 4l, and 4m) using human red blood cells as well as human embryonic kidney (HEK-293) cells showed nontoxic behavior at desired concentration. Growth kinetic and time-kill curve studies of 4l against S. pneumoniae and E. coli supported its bactericidal nature. Interestingly, compound 4l showed a synergistic effect when used in combination with ciprofloxacin against selected strains. Biofilm formation in the presence of a lead compound, as assessed by XTT assay, showed complete disruption of the bacterial biofilm visualized by scanning electron microscopy. Overall, the findings suggest 4l to be considered as a promising lead for further development as an antibacterial agent.},
}
@article {pmid31646145,
year = {2019},
author = {Aliramezani, A and Soleimani, M and Fard, RMN and Nojoomi, F},
title = {Virulence determinants and biofilm formation of Acinetobacter baumannii isolated from hospitalized patients.},
journal = {Germs},
volume = {9},
number = {3},
pages = {148-153},
pmid = {31646145},
issn = {2248-2997},
abstract = {Introduction: Acinetobacter baumannii are nosocomial bacteria that are responsible for outbreaks and severe infections in hospitalized patients globally. The major target of this study was the characterization of virulence determinants and biofilm formation of A. baumannii isolates from hospitalized patients.<br><br>Methods: In total, 100 A. baumannii were collected from three hospitals in Tehran, Iran, 2017-2018. The isolates were assessed using phenotypic and genotypic methods and then screened for virulence factor encoding genes such as plcN and lasB using conventional polymerase chain reaction. Furthermore, bacterial biofilm formation, motility and hemolytic and proteolytic activities were assessed.<br><br>Results: Of 100 A. baumannii isolates, 20 isolates included plcN and four isolates included lasB using PCR assay. Overall, 21 isolates were negative for biofilm formation while 45, 20 and 14 of the total isolates were reported as weak, moderate and strong biofilm producers, respectively. All isolates were positive for bap genes using PCR. Moreover, 35 isolates were motile on Luria-Bertani media, 47 isolates were α-hemolytic on Brucella blood agar media and all isolates displayed proteolytic activity.<br><br>Conclusions: Healthcare-associated infections with A. baumannii are a major concern, importantly due to their potency to acquire virulence factor genes. Therefore, shedding light in the discovery of new antimicrobial and/or therapeutic agents against virulent A. baumannii strains seem to be necessary.},
}
@article {pmid31646012,
year = {2019},
author = {Masters, EA and Trombetta, RP and de Mesy Bentley, KL and Boyce, BF and Gill, AL and Gill, SR and Nishitani, K and Ishikawa, M and Morita, Y and Ito, H and Bello-Irizarry, SN and Ninomiya, M and Brodell, JD and Lee, CC and Hao, SP and Oh, I and Xie, C and Awad, HA and Daiss, JL and Owen, JR and Kates, SL and Schwarz, EM and Muthukrishnan, G},
title = {Evolving concepts in bone infection: redefining &quot;biofilm&quot;, &quot;acute vs. chronic osteomyelitis&quot;, &quot;the immune proteome&quot; and &quot;local antibiotic therapy&quot;.},
journal = {Bone research},
volume = {7},
number = {},
pages = {20},
pmid = {31646012},
issn = {2095-4700},
abstract = {Osteomyelitis is a devastating disease caused by microbial infection of bone. While the frequency of infection following elective orthopedic surgery is low, rates of reinfection are disturbingly high. Staphylococcus aureus is responsible for the majority of chronic osteomyelitis cases and is often considered to be incurable due to bacterial persistence deep within bone. Unfortunately, there is no consensus on clinical classifications of osteomyelitis and the ensuing treatment algorithm. Given the high patient morbidity, mortality, and economic burden caused by osteomyelitis, it is important to elucidate mechanisms of bone infection to inform novel strategies for prevention and curative treatment. Recent discoveries in this field have identified three distinct reservoirs of bacterial biofilm including: Staphylococcal abscess communities in the local soft tissue and bone marrow, glycocalyx formation on implant hardware and necrotic tissue, and colonization of the osteocyte-lacuno canalicular network (OLCN) of cortical bone. In contrast, S. aureus intracellular persistence in bone cells has not been substantiated in vivo, which challenges this mode of chronic osteomyelitis. There have also been major advances in our understanding of the immune proteome against S. aureus, from clinical studies of serum antibodies and media enriched for newly synthesized antibodies (MENSA), which may provide new opportunities for osteomyelitis diagnosis, prognosis, and vaccine development. Finally, novel therapies such as antimicrobial implant coatings and antibiotic impregnated 3D-printed scaffolds represent promising strategies for preventing and managing this devastating disease. Here, we review these recent advances and highlight translational opportunities towards a cure.},
}
@article {pmid31642854,
year = {2019},
author = {Chen, L and Yang, D and Feng, J and Zhang, M and Qian, Q and Zhou, Y},
title = {Switchable modulation of bacterial growth and biofilm formation based on supramolecular tripeptide amphiphiles.},
journal = {Journal of materials chemistry. B},
volume = {7},
number = {41},
pages = {6420-6427},
doi = {10.1039/c9tb00973f},
pmid = {31642854},
issn = {2050-7518},
abstract = {Design and fabrication of smart supramolecular peptide systems is an effective strategy to develop antibacterial agents that can be selectively activated/inactivated by external stimuli for combating bacterial resistance. In this work, we selectively synthesized isomeric tripeptides (i.e., Ala-Gly-Gly-OH and Gly-Gly-Ala-OH) with the simplest structures to construct a minimalistic dual-responsive supramolecular antibacterial system. To impart stimuli-responsiveness, the tripeptides were modified using a hydrophobic n-butylazobenzene tail at the N-terminal, which benefited the enhancement of the hydrophobicity of the tripeptides and they served as synergistic antibacterial moieties. Two different self-assembled 1-D morphologies (i.e., nanotwists and nanofibers) were observed under the same conditions when the position of the Ala residue was altered. More importantly, the supramolecular tripeptide amphiphiles exhibited a reversible assembly/disassembly process in response to different stimuli (i.e., light and host-guest chemistry). Based on the stimuli-responsiveness, the antibacterial/antibiofilm activities against either Gram-negative or Gram-positive bacteria could be reversibly modulated.},
}
@article {pmid31642039,
year = {2020},
author = {Ortega-Peña, S and Martínez-García, S and Rodríguez-Martínez, S and Cancino-Diaz, ME and Cancino-Diaz, JC},
title = {Overview of Staphylococcus epidermidis cell wall-anchored proteins: potential targets to inhibit biofilm formation.},
journal = {Molecular biology reports},
volume = {47},
number = {1},
pages = {771-784},
doi = {10.1007/s11033-019-05139-1},
pmid = {31642039},
issn = {1573-4978},
support = {20181167//SIP-Instituto Politécnico Nacional Mexico/ ; },
abstract = {Currently, the treatment of infections by Staphylococcus epidermidis (S. epidermidis) represents a challenge because some strains have multidrug-resistance to antimicrobial products (antibiotic and biocides) and can produce biofilms. These biofilms protect bacterial cells from both antimicrobials and the host immune response. Therefore, it is crucial to encourage research on the development of new treatments. One method is immunotherapy, targeting components of S. epidermidis, such as S. epidermidis surface (Ses) proteins. Ses is expressed constitutively in most strains, and they participate in biofilm formation. This review is an update on Ses, regarding their structure, biological function, their relationship with S. epidermidis biofilm formation, and its possible role as therapeutic targets to develop immunotherapeutic treatments to prevent infections by S. epidermidis.},
}
@article {pmid31641666,
year = {2019},
author = {Raya, S and Belbase, A and Dhakal, L and Govinda Prajapati, K and Baidya, R and Kishor Bimali, N},
title = {In-Vitro Biofilm Formation and Antimicrobial Resistance of Escherichia coli in Diabetic and Nondiabetic Patients.},
journal = {BioMed research international},
volume = {2019},
number = {},
pages = {1474578},
pmid = {31641666},
issn = {2314-6141},
abstract = {Background: Diabetic patients are more susceptible to urinary tract infection compared to nondiabetic patients, Escherichia coli being the most common uropathogen causing UTI. Unreasonable and incorrect antibiotic prescription for UTI in these patients may induce the development of antibiotic-resistant urinary pathogens resulting in delayed recovery and longer hospitalization. In addition to these, biofilm forming capacity of the pathogen may worsen the problem. The main aim of this cross-sectional study (conducted from March to September 2015) is to detect the biofilm forming capacity of UTI causing micro-organisms and compare the antibiotic resistance pattern of Escherichia coli, the most common cause of UTI, which will help the physician in choosing the best antibiotic.<br><br>Method: Total of 1,099 clean-catch mid stream urine (CCMSU) was processed by standard microbiological technique; 182 were from the diabetic group and 917 nondiabetic. Following identification, all isolates were subjected to antibiotic susceptibility testing using modified Kirby-Bauer disc diffusion method. In-vitro biofilm forming capacity of the isolates were detected by Microtitre plate method. The data were analyzed using SPSS software 16.<br><br>Result: Urinary tract infection was found to be significantly higher in diabetic patients (42.9%) compared to nondiabetic patients (17.4%) with Escherichia coli as the most common uropathogen in both diabetic and nondiabetic groups. Similarly, UTI was more common in elderly population (29.5%). Imipenem, nitrofurantoin and amikacin were found to be the most effective drug for uropathogenic E. coli in both diabetic and nondiabetic patients, whereas amoxicillin, ciprofloxacin, and cotrimoxazole were least effective. Of the total bacterial isolates, 43.3% showed positive results for in-vitro biofilm production by the Microtitre plate method. A significantly higher resistance rate was observed among biofilm producing E. coli for quinolones, cotrimoxazole, and third generation cephalosporin ceftriaxone. Most of the biofilm producers (79.5%) were found to be MDR (p-value 0.015).<br><br>Conclusion: Elderly populations with diabetes are at a higher risk of UTI. Higher biofilm production and resistance to in-use antimicrobial agents in this study render its inefficacy for empirical treatment and point out the importance of biofilm screening to ensure the effective management of infection.},
}
@article {pmid31640553,
year = {2019},
author = {Król, JE and Hall, DC and Balashov, S and Pastor, S and Sibert, J and McCaffrey, J and Lang, S and Ehrlich, RL and Earl, J and Mell, JC and Xiao, M and Ehrlich, GD},
title = {Genome rearrangements induce biofilm formation in Escherichia coli C - an old model organism with a new application in biofilm research.},
journal = {BMC genomics},
volume = {20},
number = {1},
pages = {767},
pmid = {31640553},
issn = {1471-2164},
support = {5R01 DC 02148/DC/NIDCD NIH HHS/United States ; },
abstract = {BACKGROUND: Escherichia coli C forms more robust biofilms than other laboratory strains. Biofilm formation and cell aggregation under a high shear force depend on temperature and salt concentrations. It is the last of five E. coli strains (C, K12, B, W, Crooks) designated as safe for laboratory purposes whose genome has not been sequenced.<br><br>RESULTS: Here we present the complete genomic sequence of this strain in which we utilized both long-read PacBio-based sequencing and high resolution optical mapping to confirm a large inversion in comparison to the other laboratory strains. Notably, DNA sequence comparison revealed the absence of several genes thought to be involved in biofilm formation, including antigen 43, waaSBOJYZUL for lipopolysaccharide (LPS) synthesis, and cpsB for curli synthesis. The first main difference we identified that likely affects biofilm formation is the presence of an IS3-like insertion sequence in front of the carbon storage regulator csrA gene. This insertion is located 86 bp upstream of the csrA start codon inside the - 35 region of P4 promoter and blocks the transcription from the sigma32 and sigma70 promoters P1-P3 located further upstream. The second is the presence of an IS5/IS1182 in front of the csgD gene. And finally, E. coli C encodes an additional sigma70 subunit driven by the same IS3-like insertion sequence. Promoter analyses using GFP gene fusions provided insights into understanding this regulatory pathway in E. coli.<br><br>CONCLUSIONS: Biofilms are crucial for bacterial survival, adaptation, and dissemination in natural, industrial, and medical environments. Most laboratory strains of E. coli grown for decades in vitro have evolved and lost their ability to form biofilm, while environmental isolates that can cause infections and diseases are not safe to work with. Here, we show that the historic laboratory strain of E. coli C produces a robust biofilm and can be used as a model organism for multicellular bacterial research. Furthermore, we ascertained the full genomic sequence of this classic strain, which provides for a base level of characterization and makes it useful for many biofilm-based applications.},
}
@article {pmid31638894,
year = {2019},
author = {Di Domenico, EG and Rimoldi, SG and Cavallo, I and D'Agosto, G and Trento, E and Cagnoni, G and Palazzin, A and Pagani, C and Romeri, F and De Vecchi, E and Schiavini, M and Secchi, D and Antona, C and Rizzardini, G and Dichirico, RB and Toma, L and Kovacs, D and Cardinali, G and Gallo, MT and Gismondo, MR and Ensoli, F},
title = {Microbial biofilm correlates with an increased antibiotic tolerance and poor therapeutic outcome in infective endocarditis.},
journal = {BMC microbiology},
volume = {19},
number = {1},
pages = {228},
pmid = {31638894},
issn = {1471-2180},
abstract = {BACKGROUND: Infective endocarditis (IE) is associated with high rates of mortality. Prolonged treatments with high-dose intravenous antibiotics often fail to eradicate the infection, frequently leading to high-risk surgical intervention. By providing a mechanism of antibiotic tolerance, which escapes conventional antibiotic susceptibility profiling, microbial biofilm represents a key diagnostic and therapeutic challenge for clinicians. This study aims at assessing a rapid biofilm identification assay and a targeted antimicrobial susceptibility profile of biofilm-growing bacteria in patients with IE, which were unresponsive to antibiotic therapy.<br><br>RESULTS: Staphylococcus aureus was the most common isolate (50%), followed by Enterococcus faecalis (25%) and Streptococcus gallolyticus (25%). All microbial isolates were found to be capable of producing large, structured biofilms in vitro. As expected, antibiotic treatment either administered on the basis of antibiogram or chosen empirically among those considered first-line antibiotics for IE, including ceftriaxone, daptomycin, tigecycline and vancomycin, was not effective at eradicating biofilm-growing bacteria. Conversely, antimicrobial susceptibility profile of biofilm-growing bacteria indicated that teicoplanin, oxacillin and fusidic acid were most effective against S. aureus biofilm, while ampicillin was the most active against S. gallolyticus and E. faecalis biofilm, respectively.<br><br>CONCLUSIONS: This study indicates that biofilm-producing bacteria, from surgically treated IE, display a high tolerance to antibiotics, which is undetected by conventional antibiograms. The rapid identification and antimicrobial tolerance profiling of biofilm-growing bacteria in IE can provide key information for both antimicrobial therapy and prevention strategies.},
}
@article {pmid31637837,
year = {2019},
author = {Røder, HL and Olsen, NMC and Whiteley, M and Burmølle, M},
title = {Unravelling interspecies interactions across heterogeneities in complex biofilm communities.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.14834},
pmid = {31637837},
issn = {1462-2920},
support = {10098//Villum Fonden/ ; },
abstract = {The importance of microbial biofilms has been well-recognized for several decades, and focus is now shifting towards investigating multispecies biofilm communities rather than mono- or dual-species biofilms. Therefore, the demand for techniques that provide a sufficient amount of information at adequate resolution is increasing. One major challenge for multispecies studies is that diversity and spatial organization often lead to a high degree of spatial and chemical heterogeneity. Many current approaches do not account for such heterogeneity and therefore only provide average information (-omics techniques in particular), which could obscure important information about the community. Here, we bring attention to the issues of heterogeneity when analysing synthetic multi-species biofilms, in vitro, and the importance of multi-scale approaches. We provide an overview of current and newer approaches that can be applied to biofilm communities, in order to elucidate interactions at the appropriate scale.},
}
@article {pmid31637462,
year = {2019},
author = {Birarda, G and Delneri, A and Lagatolla, C and Parisse, P and Cescutti, P and Vaccari, L and Rizzo, R},
title = {Multi-technique microscopy investigation on bacterial biofilm matrices: a study on Klebsiella pneumoniae clinical strains.},
journal = {Analytical and bioanalytical chemistry},
volume = {411},
number = {27},
pages = {7315-7325},
doi = {10.1007/s00216-019-02111-7},
pmid = {31637462},
issn = {1618-2650},
support = {FRA15//University of Trieste/ ; },
mesh = {Biofilms/*growth &amp; development ; Extracellular Polymeric Substance Matrix/chemistry/*metabolism/ultrastructure ; Humans ; Klebsiella Infections/*microbiology ; Klebsiella pneumoniae/chemistry/*physiology/ultrastructure ; Microscopy, Atomic Force ; Microscopy, Confocal ; Spectrophotometry, Infrared ; },
abstract = {Biofilms are communities of bacteria living embedded in a highly hydrated matrix composed of polysaccharides, proteins, and extracellular DNA. This life style confers numerous advantages to bacteria including protection against external threats. However, they also contribute to increase bacterial resistance against antimicrobials, an issue particularly relevant in dangerous infections. Due to the complexity of the matrix, few information is present in the literature on details of its architecture including the spatial distribution of the macromolecular components which might give hints on the way the biofilm scaffold is built up by bacteria. In this study, we investigated the possibility to combine well-established microbiological procedures with advanced microscopies to get information on composition and distribution of the macromolecular components of biofilm matrices. To this, confocal microscopy, diffraction-limited infrared (IR) spectral imaging, and atomic force microscopy (AFM) were used to explore biofilm produced by a clinical strain of Klebsiella pneumoniae. IR imaging permitted to have clues on how the biofilm grows and spreads on surfaces, and the local distribution of the components within it. Through the analysis of the pure component spectra, it was possible to assess the chemical and structural composition of the saccaridic matrix, confirming the data obtained by NMR. It was also possible to follow the time course of biofilm from 6 up to 48 h when the biofilm grew into a 3-dimensional multi-layered structure, characteristic of colonies of bacteria linked together by a complex matrix. In addition, nanoFTIR and AFM investigations allowed the estimation of biofilm growth in the vertical direction and the morphological analysis of bacterial colonies at different time points and the evaluation of the chemical composition at the nanoscale.},
}
@article {pmid31635733,
year = {2020},
author = {Jung, J and Bae, Y and Kwan Cho, Y and Ren, X and Sun, Y},
title = {Structural insights into conformation of amphiphilic quaternary ammonium chitosans to control fungicidal and anti-biofilm functions.},
journal = {Carbohydrate polymers},
volume = {228},
number = {},
pages = {115391},
doi = {10.1016/j.carbpol.2019.115391},
pmid = {31635733},
issn = {1879-1344},
abstract = {Fungal biofilm formation is an emerging problem in a wide range of health-related applications. This study aims to design and synthesize amphiphilic quaternary ammonium chitosans (AQACs) that could bind onto fungal biofilms to kill adherent fungal cells, and establish their structural/fungicidal activity relationships. AQACs with different hydrophobic alkyl chain length (C4, C8, and C12) were synthesized by quaternization of 3-bromopropionic acid with the corresponding tertiary amines, followed by reacting with chitosan using the EDC/NHS chemistry. The new AQACs were soluble in water, yet formed self-aggregates in the solution with different sizes. In antifungal tests against free-floating Candida albicans, shorter alkyl chains (C4) in the AQACs resulted in the most potent fungicidal effect. However, in the treatment of Candida biofilms formed on solid surfaces, AQACs with longer alkyl chains (C8 and C12) were much more effective than their shorter chain counterpart (C4). The effects of alkyl chain self-aggregation on the opposite trend in fungicidal and anti-biofilm activities were discussed. All the AQACs showed excellent cytocompatibility with mammalian cells.},
}
@article {pmid31634700,
year = {2020},
author = {Sun, Y and Lang, Y and Yan, Z and Wang, L and Zhang, Z},
title = {High-throughput sequencing analysis of marine pioneer surface-biofilm bacteria communities on different PDMS-based coatings.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {185},
number = {},
pages = {110538},
doi = {10.1016/j.colsurfb.2019.110538},
pmid = {31634700},
issn = {1873-4367},
abstract = {Marine biofilms, the attachment of marine microorganisms on artificial surfaces in natural seawater, play critical roles in the development of marine biofouling, which pave ways for the settlement and colonization of sessile invertebrate larvae. Despite the excellent microbe-inhibitory effect of polydimethylsiloxane (PDMS)-based coatings, marine bacteria could still attach to surfaces and form natural biofilms. However, there is little information available on the common structural features of pioneer surface-biofilm bacteria (PSB) communities on different PDMS-based coatings with regard to their compositions, distributions and diversity. Herein, the present study aims to explore the compositional and structural features of the PSB communities on different PDMS-based coatings using 16S rRNA gene amplicon sequencing in terms of the taxonomic structures at phylum, family and genus level. The results revealed the PSB communities on different PDMS-based coatings possessed high similarities in compositional, structural and diversity features, but varied greatly in relative abundance and distributions. Proteobacteria was the most diverse and overwhelming phylum in biofilms formed on all PDMS-based coatings, followed by Cyanobacteria. In addition, the decreased abundance of Proteobacteria and the increased abundance of Cyanobacteria on the carbon nanotubes (CNTs)-modifed PDMS composites (CPCs) may contribute to their differential anti-biofouling effect against the colonization of juvenile macrofoulers.},
}
@article {pmid31632948,
year = {2019},
author = {Walsh, DJ and Livinghouse, T and Goeres, DM and Mettler, M and Stewart, PS},
title = {Antimicrobial Activity of Naturally Occurring Phenols and Derivatives Against Biofilm and Planktonic Bacteria.},
journal = {Frontiers in chemistry},
volume = {7},
number = {},
pages = {653},
pmid = {31632948},
issn = {2296-2646},
abstract = {Biofilm-forming bacteria present formidable challenges across diverse settings, and there is a need for new antimicrobial agents that are both environmentally acceptable and relatively potent against microorganisms in the biofilm state. The antimicrobial activity of three naturally occurring, low molecular weight, phenols, and their derivatives were evaluated against planktonic and biofilm Staphylococcus epidermidis and Pseudomonas aeruginosa. The structure activity relationships of eugenol, thymol, carvacrol, and their corresponding 2- and 4-allyl, 2-methallyl, and 2- and 4-n-propyl derivatives were evaluated. Allyl derivatives showed a consistent increased potency with both killing and inhibiting planktonic cells but they exhibited a decrease in potency against biofilms. This result underscores the importance of using biofilm assays to develop structure-activity relationships when the end target is biofilm.},
}
@article {pmid31632023,
year = {2019},
author = {Fang, JY and Lin, YK and Wang, PW and Alalaiwe, A and Yang, YC and Yang, SC},
title = {The Droplet-Size Effect Of Squalene@cetylpyridinium Chloride Nanoemulsions On Antimicrobial Potency Against Planktonic And Biofilm MRSA.},
journal = {International journal of nanomedicine},
volume = {14},
number = {},
pages = {8133-8147},
pmid = {31632023},
issn = {1178-2013},
mesh = {Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents/*pharmacology ; Biofilms/*drug effects ; Cations ; Cetylpyridinium/*pharmacology ; Emulsions ; Humans ; Methicillin-Resistant Staphylococcus aureus/drug effects/genetics/*physiology ; Micelles ; Microbial Sensitivity Tests ; Nanoparticles/*chemistry/ultrastructure ; Plankton/*drug effects ; Proteomics ; Squalene/*pharmacology ; },
abstract = {Background: It is important to explore the interaction between antibacterial nanoparticles and microbes for understanding bactericidal activity and developing novel applications. It is possible that the nanoparticulate size can govern the antibacterial potency.<br><br>Purpose: The purpose of this study was to evaluate the antimicrobial and antibiofilm properties of cetylpyridinium chloride (CPC)-decorated nanoemulsions against methicillin-resistant Staphylococcus aureus (MRSA).<br><br>Methods: The droplet size could be adjusted by varying the percentage of squalene, the main ingredient of the oily core.<br><br>Results: We fabricated cationic nanoemulsions of three different sizes, 55, 165, and 245 nm. The nanoemulsions showed greater storage stability than the self-assembled CPC micelles. The tested nanoemulsions exhibited more antimicrobial activity against Gram-positive bacteria than Gram-negative bacteria and fungi. The killing of MRSA was mainly induced by direct cell-membrane damage. This rupture led to the leakage of cytoplasmic DNA and proteins. The nanoemulsions might also degrade the DNA helix and disturb protein synthesis. The proteomic analysis indicated the significant downregulation of DNA-directed RNA polymerase (RNAP) subunits β and β'. The antibacterial effect of nanoemulsions increased with decreasing droplet size in the biofilm MRSA but not planktonic MRSA. The small-sized nanoemulsions had potent antibiofilm activity that showed a colony-forming unit (CFU) reduction of 10-fold compared with the control. The loss of total DNA concentration also negatively correlated with the nanoemulsion size.<br><br>Conclusion: The present report established a foundation for the development of squalene@CPC nanosystems against drug-resistant S. aureus.},
}
@article {pmid31631801,
year = {2019},
author = {Sun, F and Yuan, Q and Wang, Y and Cheng, L and Li, X and Feng, W and Xia, P},
title = {Sub-minimum inhibitory concentration ceftazidime inhibits Escherichia coli biofilm formation by influencing the levels of the ibpA gene and extracellular indole.},
journal = {Journal of chemotherapy (Florence, Italy)},
volume = {},
number = {},
pages = {1-8},
doi = {10.1080/1120009X.2019.1678913},
pmid = {31631801},
issn = {1973-9478},
abstract = {Escherichia coli is a common pathogen of bacterial biofilm infections. Sub-minimum inhibitory concentration ceftazidime (sub-MIC CAZ) could inhibit the biofilm formation of E. coli. Deletion of the ibpAB genes could increase the extracellular indole concentration of E. coli and then inhibit biofilm formation. Therefore, we speculated that sub-MIC CAZ might inhibit biofilm formation via ibpAB. In this study, the results showed that sub-MIC CAZ could significantly inhibit biofilm formation, swimming motility and the expression of the ibpA gene, while it could increase the expression of tnaA gene and extracellular indole concentration. Knockout of the ibpA gene resulted in a decrease in biofilm formation and swimming motility and an increase in the indole concentration. When treated with sub-MIC CAZ, the tnaA gene expression, indole concentration, biofilm formation and swimming motility of MG1655 ΔibpA were similar to those of the control group. The results indicated that sub-MIC CAZ might inhibit the biofilm formation of E. coli by increasing the extracellular indole concentration and downregulating the ibpA gene.},
}
@article {pmid31631600,
year = {2019},
author = {Pu, QK and Liu, SJ and Huang, H and Xiong, JF and Zhnang, L and Fang, Z and Wang, C},
title = {[Sterilization Effect of an Atmospheric Low Temperature Plasma Jet on Candida albicans Biofilm].},
journal = {Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition},
volume = {50},
number = {3},
pages = {339-343},
pmid = {31631600},
issn = {1672-173X},
mesh = {*Biofilms ; Candida albicans/*drug effects ; Cold Temperature ; Plasma Gases/*pharmacology ; Reproducibility of Results ; *Sterilization ; },
abstract = {Objective: To evaluate the sterilization effect of new designed atmospheric low temperature plasma jet on Candida albicans (C. albicans) biofilm.<br><br>Methods: C. albicans was grown into the logarithmic phase, and then was added to polystyrene 24-well microtitre plate. The amount of germs were calculated by viable plate counting to determine the reproducibility of each biofilm well. The germs in biofilm were treated by plasma for different exposure time and then the survived germs were quantified by plate counting, the dead cells were determined by staining the biofilm with propidium iodide (PI), and the ultrastructural changes of the germs in biofilm were observed by transmission electron microscopy (TEM).<br><br>Results: When incubated for 72 h, germs tightly polymerized and classical mature biofilm were formed. This atmospheric low temperature plasma jet could inactivate C. albicans biofilm within a short exposure time. C. albicans were 90% inactivated when treated 20 s and 55 s of plasma treatment reduced bacteria populations to undetectable levels. With the increase of treatment time, enlarged fluorescent positive area appeared, and more bacteria died with the extending of exposure. The TEM scanning results showed that the new plasma jet inactivated C. albicans biofilm mainly via disrupting cell envelopes and then leading the release of cellular components, thus resulting in loss of cell viability.<br><br>Conclusion: Plasma generated from atmospheric low temperature plasma jet could damage the cell structure of C. albicans and efficiently sterilize C. albicans biofilm.},
}
@article {pmid31630921,
year = {2019},
author = {Evangelista, SS and Guimaraes, NR and Garcia, NB and Santos, SGD and Oliveira, AC},
title = {Effectiveness of manual versus automated cleaning on Staphylococcus epidermidis biofilm removal from the surface of surgical instruments.},
journal = {American journal of infection control},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ajic.2019.08.024},
pmid = {31630921},
issn = {1527-3296},
abstract = {BACKGROUND: Biofilm removal is a challenge during surgical instrument processing. We analyzed the time required for Staphylococcus epidermidis to form biofilms on surgical instruments, and how cleaning methods removed them.<br><br>METHODS: Different areas (ratchet, shank, and jaw) of straight crile forceps were contaminated by soaking in Tryptic Soy Broth containing 106 colony forming units (CFU)/mL of S epidermidis for 1, 2, 4, 6, 8, and 12 hours. S epidermidis adhesion and removal, after manual or automated ultrasonic cleaning, was evaluated by microbiological culture and scanning electron microscopy.<br><br>RESULTS: Microbial load increased with time (101-102 CFU/cm2 after 1 hour; 104 CFU/cm2 after 12 hours). Exopolysaccharide was detected after 2 hours and gradually increased thereafter. Bacterial load was reduced by 1-2 log10 after manual cleaning and 1-3 log10 after automated cleaning, but biofilms were not completely eliminated. In general, bacterial load was lower in shank fragments. This difference was significant at 6 hours.<br><br>CONCLUSIONS: Rapid adhesion of S epidermidis and exopolysaccharide formation was observed on surgical instruments. Automated cleaning was more effective than manual cleaning, but neither method removed biofilms completely. The precleaning conditions and the forceps design are critical factors in processing quality.},
}
@article {pmid31630525,
year = {2019},
author = {Cao, Y and Jana, S and Bowen, L and Tan, X and Liu, H and Rostami, N and Brown, J and Jakubovics, NS and Chen, J},
title = {Hierarchical Rose Petal Surfaces Delay the Early-Stage Bacterial Biofilm Growth.},
journal = {Langmuir : the ACS journal of surfaces and colloids},
volume = {35},
number = {45},
pages = {14670-14680},
doi = {10.1021/acs.langmuir.9b02367},
pmid = {31630525},
issn = {1520-5827},
abstract = {A variety of natural surfaces exhibit antibacterial properties; as a result, significant efforts in the past decade have been dedicated toward fabrication of biomimetic surfaces that can help control biofilm growth. Examples of such surfaces include rose petals, which possess hierarchical structures like the micropapillae measuring tens of microns and nanofolds that range in the size of 700 ± 100 nm. We duplicated the natural structures on rose petal surfaces via a simple UV-curable nanocasting technique and tested the efficacy of these artificial surfaces in preventing biofilm growth using clinically relevant bacteria strains. The rose petal-structured surfaces exhibited hydrophobicity (contact angle (CA) ≈ 130.8° ± 4.3°) and high CA hysteresis (∼91.0° ± 4.9°). Water droplets on rose petal replicas evaporated following the constant contact line mode, indicating the likely coexistence of both Cassie and Wenzel states (Cassie-Baxter impregnating the wetting state). Fluorescence microscopy and image analysis revealed the significantly lower attachment of Staphylococcus epidermidis (86.1 ± 6.2% less) and Pseudomonas aeruginosa (85.9 ± 3.2% less) on the rose petal-structured surfaces, compared with flat surfaces over a period of 2 h. An extensive biofilm matrix was observed in biofilms formed by both species on flat surfaces after prolonged growth (several days), but was less apparent on rose petal-biomimetic surfaces. In addition, the biomass of S. epidermidis (63.2 ± 9.4% less) and P. aeruginosa (76.0 ± 10.0% less) biofilms were significantly reduced on the rose petal-structured surfaces, in comparison to the flat surfaces. By comparing P. aeruginosa growth on representative unitary nanopillars, we demonstrated that hierarchical structures are more effective in delaying biofilm growth. The mechanisms are two-fold: (1) the nanofolds across the hemispherical micropapillae restrict initial attachment of bacterial cells and delay the direct contact of cells via cell alignment and (2) the hemispherical micropapillae arrays isolate bacterial clusters and inhibit the formation of a fibrous network. The hierarchical features on rose petal surfaces may be useful for developing strategies to control biofilm formation in medical and industrial contexts.},
}
@article {pmid31630018,
year = {2020},
author = {Liu, C and Song, D and Zhang, W and He, Q and Huangfu, X and Sun, S and Sun, Z and Cheng, W and Ma, J},
title = {Constructing zwitterionic polymer brush layer to enhance gravity-driven membrane performance by governing biofilm formation.},
journal = {Water research},
volume = {168},
number = {},
pages = {115181},
doi = {10.1016/j.watres.2019.115181},
pmid = {31630018},
issn = {1879-2448},
mesh = {Biofilms ; Filtration ; *Membranes, Artificial ; *Polymers ; Sewage ; },
abstract = {In this study, zwitterionic polymer brushes with controlled architecture were grafted on the surface of gravity-driven membrane (GDM) via surface-initiated reaction to impart antifouling property. A variety of membrane characterization techniques were conducted to demonstrate the successful functionalization of zwitterionic polymers on PVDF hollow fiber membrane. The membrane underwent 90 min of reaction time possessing strong hydrophilicity and high permeability was determined as the optimal modified membrane. Long-term GDM dynamic fouling experiments operated for 30 days using sewage wastewater as feed solution indicated zwitterionic polymer modified membrane exhibit excellent membrane fouling resistance thus enhanced stable flux. Confocal laser scanning microscopy (CLSM) imaging implied that zwitterionic polymer modification significantly inhibit the adsorption of extracellular polymeric substances (EPS) which dominates fouling propensity, resulting in the formation of a thin biofilm with high porosity under synthetic functions of foulants deposition and microbial activities. Interfacial free energy prediction affirmed the presence of zwitterionic functional layer on membrane surface could substantially decrease the interactions (e.g., electrostatic attractions and hydrophobic effects) between membrane and foulants, thereby reduced flux decline and high stable flux. Our study suggests surface hydrophilic functionalization shows promising potential for improving the performance of ultra-low pressure filtration.},
}
@article {pmid31630005,
year = {2020},
author = {Sebelemetja, M and Moeno, S and Patel, M},
title = {Anti-acidogenic, anti-biofilm and slow release properties of Dodonaea viscosa var. angustifolia flavone stabilized polymeric nanoparticles.},
journal = {Archives of oral biology},
volume = {109},
number = {},
pages = {104586},
doi = {10.1016/j.archoralbio.2019.104586},
pmid = {31630005},
issn = {1879-1506},
abstract = {OBJECTIVE: Dental caries is caused by plaque associated oral bacteria including a pioneer species Streptococcus mutans. It has ability to form biofilm and produce acids in the oral cavity. Many oral hygiene products containing plant derived compounds have been investigated for their anti-S. mutans activity. Dodonaea viscosa var. angustifolia (DVA), has been found to have this property. However, beneficial concentrations are difficult to maintain in the oral cavity due to continual saliva flow which can be overcome using nanotechnology. The aim of this study was to investigate the anti-acidogenic, anti-biofilm and slow release properties of DVA derived flavone stabilized polymeric nanoparticles.<br><br>METHODS: Crude extract prepared from DVA leaves was fractionated to produce subfractions and the beneficial subfraction (F5.1) was obtained. Polymeric nanoparticles (PLGA-PEG) were prepared, stabilized with the DVA subfraction (F5.1/NPs) and characterized. Anti-S. mutans, anti-acidogenic and antibiofilm properties were determined. The subfraction release profile (substantivity) and cytotoxicity was determined. Results were analyzed using the Wilcoxon sum test (Mann-Whitney).<br><br>RESULTS: F5.1/NPs showed anti-S. mutans property (MIC 1.56 mg/ml). Subinhibitory concentrations of these nanoparticles significantly reduced the acid production in S. mutans (p < 0.01) and also reduced the biofilm formation by 92%. The retention and slow release of the beneficial compound was detected up to 12 h, reaching 0.1 mg/ml concentration at pH 7.4 after 4 h and at pH 5.5 after 5 h. IC50 of F5.1/NPs was 62.5 µg/ml.<br><br>CONCLUSION: the DVA flavone containing nanoparticles showed anticariogenic activity with improved substantivity. Therefore, they have potential for use to control dental caries.},
}
@article {pmid31629797,
year = {2019},
author = {Ohadi, M and Forootanfar, H and Dehghannoudeh, G and Eslaminejad, T and Ameri, A and Shakibaie, M and Adeli-Sardou, M},
title = {Antimicrobial, anti-biofilm, and anti-proliferative activities of lipopeptide biosurfactant produced by Acinetobacter junii B6.},
journal = {Microbial pathogenesis},
volume = {138},
number = {},
pages = {103806},
doi = {10.1016/j.micpath.2019.103806},
pmid = {31629797},
issn = {1096-1208},
abstract = {Lipopeptide biosurfactants (LPBs) are amphiphilic compounds produced by microorganisms exhibiting various biological activities. The main aim of the present study was to assess the in vitro antimicrobial, anti-biofilm, and cytotoxic effects of LPB produced by Acinetobacter junii (AjL). We determined AjL minimum inhibitory concentration (MIC) against both Gram-positive and Gram-negative bacteria as well as two fungal strains. Also, the anti-biofilm activity of AjL against the biofilm produced by clinically isolated bacterial strains was investigated. The AjL non-selectively showed activity against both Gram-positive and Gram-negative bacterial strains. The obtained results of the present study exhibited that the AjL in concentrations nearly below critical micelle concentration (CMC) has an effective antibacterial activity. It was found that the MIC values of AjL were lower than standard antifungal and it exhibited nearly 100% inhibition against Candida utilis. The attained results of the biofilm formation revealed that AjL disrupted the biofilm of Proteus mirabilis, Staphylococcus aureus, and Pseudomonas aeruginosa at 1250 μg/ml and 2500 μg/ml concentrations. The attained results of cytotoxic effect (determined by WST-1 assay) of the AjL revealed IC50 of 7.8 ± 0.4 mg/ml, 2.4 ± 0.5 mg/ml, and 5.7 ± 0.1 mg/ml, against U87, KB, and HUVEC cell lines, respectively. The results indicated that AjL has a potential application in the relatively new field of biomedicine.},
}
@article {pmid31628906,
year = {2020},
author = {Ghasemi, M and Jenkins, B and Doxey, AC and Sivaloganathan, S},
title = {A study of nitric oxide dynamics in a growing biofilm using a density dependent reaction-diffusion model.},
journal = {Journal of theoretical biology},
volume = {485},
number = {},
pages = {110053},
doi = {10.1016/j.jtbi.2019.110053},
pmid = {31628906},
issn = {1095-8541},
abstract = {One of a number of critical roles played by NO· as a chemical weapon (generated by the immune system) is to neutralize pathogens. However, the virulence of pathogens depends on the production activity of reductants to detoxify NO·. Broad reactivity of NO· makes it complicated to predict the fate of NO· inside bacteria and its effects on the treatment of any infection. Here, we present a mathematical model of biofilm response to NO·, as a stressor. The model is comprised of a PDE system of highly nonlinear reaction-diffusion equations that we study in computer simulations to determine the positive and negative effects of key parameters on bacterial defenses against NO·. From the reported results, we conjecture that the oscillatory behavior of NO· under a microaerobic regime is a temporal phenomenon and does not give rise to a spatial pattern. It is also shown computationally that decreasing the initial size of the biofilm colony negatively impacts the functionality of reducing agents that deactivate NO·. Whereas nutrient deprivation results in the development of biofilms with heterogeneous structure, its effect on the activity of NO· reductants depends on the oxygen availability, biofilm size, and the amount of NO·.},
}
@article {pmid31627387,
year = {2019},
author = {Shetty, D and Abrahante, JE and Chekabab, SM and Wu, X and Korber, DR and Vidovic, S},
title = {Role of CpxR in Biofilm Development: Expression of Key Fimbrial, O-Antigen and Virulence Operons of Salmonella Enteritidis.},
journal = {International journal of molecular sciences},
volume = {20},
number = {20},
pages = {},
pmid = {31627387},
issn = {1422-0067},
abstract = {Salmonella Enteritidis is a non-typhoidal serovar of great public health significance worldwide. The RpoE sigma factor and CpxRA two-component system are the major regulators of the extracytoplasmic stress response. In this study, we found that the CpxR has highly significant, but opposite effects on the auto-aggregation and swarming motility of S. Enteritidis. Auto-aggregation was negatively affected in the ∆cpxR mutant, whereas the same mutant significantly out-performed its wild-type counterpart with respect to swarming motility, indicating that the CpxR plays a role in biofilm-associated phenotypes. Indeed, biofilm-related assays showed that the CpxR is of critical importance in biofilm development under both static (microtiter plate) and dynamic (flow cell) media flow conditions. In contrast, the RpoE sigma factor showed no significant role in biofilm development under dynamic conditions. Transcriptomic analysis revealed that the cpxR mutation negatively affected the constitutive expression of the operons critical for biosynthesis of O-antigen and adherence, but positively affected the expression of virulence genes critical for Salmonella-mediated endocytosis. Conversely, CpxR induced the expression of curli csgAB and fimbrial stdAC operons only during biofilm development and flagellar motAB and fliL operons exclusively during the planktonic phase, indicating a responsive biofilm-associated loop of the CpxR regulator.},
}
@article {pmid31626589,
year = {2019},
author = {Mangas, EL and Rubio, A and Álvarez-Marín, R and Labrador-Herrera, G and Pachón, J and Pachón-Ibáñez, ME and Divina, F and Pérez-Pulido, AJ},
title = {Pangenome of Acinetobacter baumannii uncovers two groups of genomes, one of them with genes involved in CRISPR/Cas defence systems associated with the absence of plasmids and exclusive genes for biofilm formation.},
journal = {Microbial genomics},
volume = {5},
number = {11},
pages = {},
pmid = {31626589},
issn = {2057-5858},
abstract = {Acinetobacter baumannii is an opportunistic bacterium that causes hospital-acquired infections with a high mortality and morbidity, since there are strains resistant to virtually any kind of antibiotic. The chase to find novel strategies to fight against this microbe can be favoured by knowledge of the complete catalogue of genes of the species, and their relationship with the specific characteristics of different isolates. In this work, we performed a genomics analysis of almost 2500 strains. Two different groups of genomes were found based on the number of shared genes. One of these groups rarely has plasmids, and bears clustered regularly interspaced short palindromic repeat (CRISPR) sequences, in addition to CRISPR-associated genes (cas genes) or restriction-modification system genes. This fact strongly supports the lack of plasmids. Furthermore, the scarce plasmids in this group also bear CRISPR sequences, and specifically contain genes involved in prokaryotic toxin-antitoxin systems that could either act as the still little known CRISPR type IV system or be the precursors of other novel CRISPR/Cas systems. In addition, a limited set of strains present a new cas9-like gene, which may complement the other cas genes in inhibiting the entrance of new plasmids into the bacteria. Finally, this group has exclusive genes involved in biofilm formation, which would connect CRISPR systems to the biogenesis of these bacterial resistance structures.},
}
@article {pmid31625519,
year = {2019},
author = {Behzadpour, N and Akbari, N and Sattarahmady, N},
title = {Photothermal inactivation of methicillin-resistant Staphylococcus aureus: anti-biofilm mediated by a polypyrrole-carbon nanocomposite.},
journal = {IET nanobiotechnology},
volume = {13},
number = {8},
pages = {800-807},
doi = {10.1049/iet-nbt.2018.5340},
pmid = {31625519},
issn = {1751-875X},
abstract = {Widespread resistance to antibiotics amongst pathogens has become a tremendous challenge of high morbidity and mortality rates which increases the needs to exploring novel methods of treatment. An efficient antimicrobial procedure to root out pathogenic bacteria is photothermal therapy. In this study, antimicrobial effects of a polypyrrole-carbon nanocomposite (PPy-C) upon laser irradiation in order to destroy the pathogenic gram-positive bacterium, methicillin-resistant Staphylococcus aureus (MRSA) were assessed. The bacterial cells were incubated with 500, 750 and 1000 μg ml-1 concentrations of PPy-C and irradiated with an 808-nm laser at a power density of 1.0 W cm-2. To indicate the biocompatibility and toxic effect of the nanocomposite without and with laser irradiation, the authors counted the number of CFUs and compared it to an untreated sample. Antibacterial mechanisms of PPy-C were assessed through temperature increment, reactive oxygen species production, and protein and DNA leakages. Photothermal heating assay showed that 26°C temperature increases in the presence of 1000 µg ml-1 PPy-C led to >98% killing of MRSA. Furthermore, 20 min radiation of near-infrared light to PPy-C in different concentrations indicated destruction and reduction in the MRSA biofilm formation. Therefore, PPy-C was introduced as a photothermal absorber with a bactericidal effect in MRSA.},
}
@article {pmid31625441,
year = {2019},
author = {Bombarda, GF and Rosalen, PL and Paganini, ER and Garcia, MA and Silva, DR and Lazarini, JG and Freires, IA and Regasini, LO and Sardi, JC},
title = {Bioactive molecule optimized for biofilm reduction related to childhood caries.},
journal = {Future microbiology},
volume = {14},
number = {},
pages = {1207-1220},
doi = {10.2217/fmb-2019-0144},
pmid = {31625441},
issn = {1746-0921},
abstract = {Aim: To evaluate antimicrobial activity of a new nitrochalcone (NC-E08) against Candida albicans and Streptococcus mutans, and its toxicity. Materials &amp; methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration/minimum fungicidal concentration (MFC) were determined against C. albicans and S. mutans, as well as antibiofilm potential and toxicity (human gingival fibroblast and Galleria mellonella). Infection and treatment were performed in G. mellonella. Results &amp; conclusion: NC-E08 showed antimicrobial activity in C. albicans (MIC: 0.054 mM) and S. mutans (MIC: 0.013 mM); 10xMIC treatment reduced 4.0 log10 biofilms for both strains and there was a reduction in survival of mixed biofilms of C. albicans and S. mutans (6.0 and 4.0 log10, respectively). NC-E08 showed no cytotoxicity in human gingival fibroblast cells and G. mellonella. NC-E08 after larval infection protected them 90% (p < 0.05). Thus, is a promising one for the prevention and treatment of S. mutans and C. albicans infections.},
}
@article {pmid31623950,
year = {2019},
author = {Robertson, SN and Childs, PG and Akinbobola, A and Henriquez, FL and Ramage, G and Reid, S and Mackay, WG and Williams, C},
title = {Reduction of Pseudomonas aeruginosa biofilm formation through the application of nanoscale vibration.},
journal = {Journal of bioscience and bioengineering},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jbiosc.2019.09.003},
pmid = {31623950},
issn = {1347-4421},
abstract = {Bacterial biofilms pose a significant burden in both healthcare and industrial environments. With the limited effectiveness of current biofilm control strategies, novel or adjunctive methods in biofilm control are being actively pursued. Reported here, is the first evidence of the application of nanovibrational stimulation (nanokicking) to reduce the biofilm formation of Pseudomonas aeruginosa. Nanoscale vertical displacements (approximately 60 nm) were imposed on P. aeruginosa cultures, with a significant reduction in biomass formation observed at frequencies between 200 and 4000 Hz at 24 h. The optimal reduction of biofilm formation was observed at 1 kHz, with changes in the physical morphology of the biofilms. Scanning electron microscope imaging of control and biofilms formed under nanovibrational stimulation gave indication of a reduction in extracellular matrix (ECM). Quantification of the carbohydrate and protein components of the ECM was performed and showed a significant reduction at 24 h at 1 kHz frequency. To model the forces being exerted by nanovibrational stimulation, laser interferometry was performed to measure the amplitudes produced across the Petri dish surfaces. Estimated peak forces on each cell, associated with the nanovibrational stimulation technique, were calculated to be in the order of 10 pN during initial biofilm formation. This represents a potential method of controlling microbial biofilm formation in a number of important settings in industry and medical related processes.},
}
@article {pmid31622708,
year = {2019},
author = {Choi, M and Hasan, N and Cao, J and Lee, J and Hlaing, SP and Yoo, JW},
title = {Chitosan-based nitric oxide-releasing dressing for anti-biofilm and in vivo healing activities in MRSA biofilm-infected wounds.},
journal = {International journal of biological macromolecules},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.ijbiomac.2019.10.009},
pmid = {31622708},
issn = {1879-0003},
abstract = {Bacterial biofilms on wounds impair the healing process and often lead to chronic wounds. Chitosan is a well-known biopolymer with antimicrobial and anti-biofilm effects. S-nitrosoglutathione (GSNO) has been identified as a promising nitric oxide (NO) donor to defend against pathogenic biofilms and enhance wound healing activities. In this study, we prepared NO-releasing chitosan film (CS/NO film) and evaluated its anti-biofilm activity and in vivo wound healing efficacy against methicillin-resistant Staphylococcus aureus (MRSA) biofilm-infected wounds in diabetic mice. The in vitro release study showed sustained release of NO over 3 days in simulated wound fluid. The CS/NO film significantly enhanced antibacterial activity against MRSA by > 3 logs reduction in bacterial viability. Moreover, CS/NO film exhibited a 3-fold higher anti-biofilm activity than the control and CS film. In in vivo MRSA biofilm-infected wounds, the CS/NO film-treated group showed faster biofilm dispersal, wound size reduction, epithelialization rates, and collagen deposition than the untreated and CS film-treated groups. Therefore, the CS/NO film investigated in this study could be a promising approach for the treatment of MRSA biofilm-infected wounds.},
}
@article {pmid31622331,
year = {2019},
author = {Kobayashi, K and Ikemoto, Y},
title = {Biofilm-associated toxin and extracellular protease cooperatively suppress competitors in Bacillus subtilis biofilms.},
journal = {PLoS genetics},
volume = {15},
number = {10},
pages = {e1008232},
pmid = {31622331},
issn = {1553-7404},
abstract = {In nature, most bacteria live in biofilms where they compete with their siblings and other species for space and nutrients. Some bacteria produce antibiotics in biofilms; however, since the diffusion of antibiotics is generally hindered in biofilms by extracellular polymeric substances, i.e., the biofilm matrix, their function remains unclear. The Bacillus subtilis yitPOM operon is a paralog of the sdpABC operon, which produces the secreted peptide toxin SDP. Unlike sdpABC, yitPOM is induced in biofilms by the DegS-DegU two-component regulatory system. High yitPOM expression leads to the production of a secreted toxin called YIT. Expression of yitQ, which lies upstream of yitPOM, confers resistance to the YIT toxin, suggesting that YitQ is an anti-toxin protein for the YIT toxin. The alternative sigma factor SigW also contributes to YIT toxin resistance. In a mutant lacking yitQ and sigW, the YIT toxin specifically inhibits biofilm formation, and the extracellular neutral protease NprB is required for this inhibition. The requirement for NprB is eliminated by Δeps and ΔbslA mutations, either of which impairs production of biofilm matrix polymers. Overexpression of biofilm matrix polymers prevents the action of the SDP toxin but not the YIT toxin. These results indicate that, unlike the SDP toxin and many conventional antibiotics, the YIT toxin can pass through layers of biofilm matrix polymers to attack cells within biofilms with assistance from NprB. When the wild-type strain and the YIT-sensitive mutant were grown together on a solid medium, the wild-type strain formed biofilms that excluded the YIT-sensitive mutant. This observation suggests that the YIT toxin protects B. subtilis biofilms against competitors. Several bacteria are known to produce antibiotics in biofilms. We propose that some bacteria including B. subtilis may have evolved specialized antibiotics that can function within biofilms.},
}
@article {pmid31621697,
year = {2019},
author = {He, Y and Wan, X and Xiao, K and Lin, W and Li, J and Li, Z and Luo, F and Tan, H and Li, J and Fu, Q},
title = {Anti-biofilm surfaces from mixed dopamine-modified polymer brushes: synergistic role of cationic and zwitterionic chains to resist staphyloccocus aureus.},
journal = {Biomaterials science},
volume = {7},
number = {12},
pages = {5369-5382},
doi = {10.1039/c9bm01275c},
pmid = {31621697},
issn = {2047-4849},
abstract = {Infections resulting from the attachment of bacteria and biofilm formation on the surface of medical implants give rise to a severe problem for medical device safety. Thus, the development of antibacterial materials that integrate bactericidal and antifouling properties is a promising approach to prevent biomaterial-associated infections. In this study, two types of dopamine-modified polymers, dopamine-terminated quaternary ammonium salt polymer (D-PQAs) with various lengths of N-alkyl chain (D-PQA4C, D-PQA8C, and D-PQA12C) and dopamine-terminated poly(sulfobetaine methacrylate) (D-PSBMA), were synthesized via atom transfer radical polymerization (ATRP). Mixed polymer brushes of D-PQAs and D-PSBMA with various ratios were well-integrated onto the surface of a silicon wafer via a facile mussel-inspired adhesion. We demonstrate that the synergistic antibacterial effect depends on both the ratio of the two components and the surface structures of the mixed polymer brushes, originating from the interactions between D-PQAs and D-PSBMA. The N-alkyl chain length of D-PQAs influenced the distribution and orientation of the alkyl chain on the mixed polymer brushes. A chart of the antibacterial efficiency of the mixed polymer brushes was obtained to reveal the synergistic role of their cationic and zwitterionic chains to resist S. aureus. The dominant amount of antifouling D-PSBMA with a minor amount of bactericidal D-PQAs with a short N-alkyl chain length facilitated the synergistic antibacterial effect. The selected polymer brushes (PSBMA/PQA4C-10%, PSBMA/PQA4C-30%, and PSBMA/PQA8C-10%) could effectively prevent biofilm formation by S. aureus for a long time, while having good biocompatibility. This work may provide a universal design strategy for the preparation of anti-biofilm and biocompatible surfaces for biomedical applications.},
}
@article {pmid31621183,
year = {2019},
author = {Hu, Y and Liu, X and Ren, ATM and Gu, JD and Cao, B},
title = {Optogenetic Modulation of a Catalytic Biofilm for the Biotransformation of Indole into Tryptophan.},
journal = {ChemSusChem},
volume = {12},
number = {23},
pages = {5142-5148},
doi = {10.1002/cssc.201902413},
pmid = {31621183},
issn = {1864-564X},
support = {MOE2017-T2-2-042//Ministry of Education - Singapore/ ; },
abstract = {In green chemical synthesis, biofilms as biocatalysts have shown great promise. Efficient biofilm-mediated biocatalysis requires the modulation of biofilm formation. Optogenetic tools are ideal to control biofilms because light is noninvasive, easily controllable, and cost-efficient. In this study, a gene circuit responsive to near-infrared (NIR) light was used to modulate the cellular level of bis-(3'-5') cyclic dimeric guanosine monophosphate (c-di-GMP), a central regulator of the prokaryote biofilm lifestyle, which allowed the regulation of biofilm formation by using NIR light. The engineered biofilm was applied to catalyze the biotransformation of indole into tryptophan in submerged biofilm reactors and NIR-light-enhanced biofilm formation resulted in an approximately 30 % increase in tryptophan yield, which demonstrates the feasibility of the application of light to modulate the formation and performance of catalytic biofilms for chemical production. The c-di-GMP-targeted optogenetic approach to modulate catalytic biofilms showcases applications for biofilm-mediated biocatalysis.},
}
@article {pmid31621139,
year = {2019},
author = {Gowri, M and Jayashree, B and Jeyakanthan, J and Girija, EK},
title = {Sertraline as a promising antifungal agent: inhibition of growth and biofilm of Candida auris with special focus on the mechanism of action in vitro.},
journal = {Journal of applied microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jam.14490},
pmid = {31621139},
issn = {1365-2672},
support = {PDF/2016/003088//Department of Science and Technology, Ministry of Science and Technology/ ; },
abstract = {AIM: The aim of this present study was to investigate the antifungal mechanism of sertraline against Candida auris (C. auris) and its effect on biofilm formation.<br><br>METHODS AND RESULTS: Sertraline, a repurposing drug with a history of human use for the treatment of depression was screened against three different isolates of C. auris, and was found to possess efficient antifungal activity. The antifungal activity of sertraline was further confirmed by killing kinetics assay and post-antifungal effect (PAFE). Sertraline inhibited C. auris yeast to hyphae conversion and further the inhibition of biofilm formation showed 71% inhibition upon treatment. Cell damage caused due to C. auris after treatment with sertraline was observed using SEM and cell membrane damage was ascertained using flow cytometry by Propidium Iodide (PI) uptake assay. The results of sorbitol protection assay and ergosterol effect assay suggested that sertraline did not affect the cell wall and did not act by binding to membrane ergosterol. The mechanism of action of sertraline against C. auris was understood through in silico docking studies that revealed the binding nature of sertraline to the sterol 14 alpha demethylase which is involved in ergosterol biosynthesis. Ergosterol that was quantified from treated cells showed a 5·5-fold decrease in ergosterol production.<br><br>CONCLUSION: Sertraline displayed promising antifungal activity against C. auris involved in candidiasis infection and the mechanism of action was predicted.<br><br>The results of this study can encourage for the development of new antifungal agents and can be promising antifungal agent against C. auris infection.},
}
@article {pmid31621078,
year = {2019},
author = {Wolf, DI and Vis, ML},
title = {Stream Algal Biofilm Community Diversity Along An Acid Mine Drainage Recovery Gradient Using Multimarker Metabarcoding.},
journal = {Journal of phycology},
volume = {},
number = {},
pages = {},
doi = {10.1111/jpy.12935},
pmid = {31621078},
issn = {1529-8817},
support = {//Ohio University Student Enhancement Award/ ; },
abstract = {In southeastern Ohio, active remediation of streams affected by Acid Mine Drainage (AMD) has proven to be successful for some streams, while others have not recovered based on macroinvertebrate assessment. In this study, biofilms were collected from three Moderately Impaired, three Recovered, and two Unimpaired streams. The biodiversity was characterized by metabarcoding using two universal barcode markers (16S and 18S) along with two algal specific markers (UPA and rbcL) and high-throughput amplicon sequencing. For each marker, the ordination of Bray-Curtis Index calculated from the total Amplicon Sequence Variants (ASVs) present in each stream showed the Unimpaired and Recovered streams clustered, while Moderately Impaired streams were more distant. Focusing on the algal ASVs, the Shannon index for the rbcL, and UPA markers showed significantly lower alpha diversity in Moderately Impaired streams compared to Unimpaired streams, but the Recovered streams were not significantly different from the other two stream categories. The two universal markers together captured all algal phyla providing an outline of the diversity, but the two algal specific markers produced a greater number of ASVs and taxonomic depth for algal taxa. Further examination of the UPA marker revealed a drastic decrease in relative abundance of diatoms in Moderately Impaired streams compared to Recovered and Unimpaired streams. Likewise, diatom genera identified in the rbcL data and indicative of stream water quality showed marked differences in relative abundance among stream categories. Although all markers were useful, the algal-specific UPA and rbcL contributed more insights into algal community differences among stream categories.},
}
@article {pmid31618938,
year = {2019},
author = {Zapién-Chavarría, KA and Plascencia-Terrazas, A and Venegas-Ortega, MG and Varillas-Torres, M and Rivera-Chavira, BE and Adame-Gallegos, JR and González-Rangel, MO and Nevárez-Moorillón, GV},
title = {Susceptibility of Multidrug-Resistant and Biofilm-Forming Uropathogens to Mexican Oregano Essential Oil.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/antibiotics8040186},
pmid = {31618938},
issn = {2079-6382},
support = {Fellowship No. 584251 for M.G.V.O.//Consejo Nacional de Ciencia y Tecnología/ ; Fellowship No. 597284 for M.V.T.//Consejo Nacional de Ciencia y Tecnología/ ; },
abstract = {Antibiotic resistance along with biofilm formation increases the difficulty for antibiotic therapy in urinary tract infections. Bioactive molecules derived from plants, such as those present in essential oils, can be used to treat bacterial infections. Oregano is one of the spices to have antimicrobial activity. Therefore, three Mexican oregano essential oils (two Lippia berlandieri Schauer and one Poliomintha longiflora) were tested for antimicrobial capacity against multidrug-resistant, biofilm-forming bacterial isolates. Clinical isolates from urinary tract infections were tested for antibiotic resistance. Multidrug-resistant isolates were evaluated for biofilm formation, and Mexican oregano antimicrobial effect was determined by the minimal inhibitory (CMI) and minimal bactericidal concentrations (CMB). The selected isolates were identified by molecular phylogenetic analysis. Sixty-one isolates were included in the study; twenty were characterized as multidrug-resistant and from those, six were strong biofilm formers. Three isolates were identified as Escherichia coli, two as Pseudomonas aeruginosa and one as Enterococcus faecalis based on the phylogenetic analysis of 16 S rRNA gene sequences. The antimicrobial effect was bactericidal; E. faecalis was the most susceptible (<200 mg/L CMI/CMB), and P. aeruginosa was the most resistant (>2,000 mg/L CMI/CMB). There was a range of 500-1000 mg/L (CMI/CMB) for the E. coli isolates. Mexican oregano essential oils demonstrated antimicrobial efficacy against multidrug-resistant clinical isolates.},
}
@article {pmid31618903,
year = {2019},
author = {Pandey, VK and Srivastava, KR and Ajmal, G and Thakur, VK and Gupta, VK and Upadhyay, SN and Mishra, PK},
title = {Differential Susceptibility of Catheter Biomaterials to Biofilm-Associated Infections and Their Remedy by Drug-Encapsulated Eudragit RL100 Nanoparticles.},
journal = {International journal of molecular sciences},
volume = {20},
number = {20},
pages = {},
pmid = {31618903},
issn = {1422-0067},
abstract = {Biofilms are the cause of major bacteriological infections in patients. The complex architecture of Escherichia coli (E. coli) biofilm attached to the surface of catheters has been studied and found to depend on the biomaterial's surface properties. The SEM micrographs and water contact angle analysis have revealed that the nature of the surface affects the growth and extent of E. coli biofilm formation. In vitro studies have revealed that the Gram-negative E. coli adherence to implanted biomaterials takes place in accordance with hydrophobicity, i.e., latex > silicone > polyurethane > stainless steel. Permanent removal of E. coli biofilm requires 50 to 200 times more gentamicin sulfate (G-S) than the minimum inhibitory concentration (MIC) to remove 90% of E. coli biofilm (MBIC90). Here, in vitro eradication of biofilm-associated infection on biomaterials has been done by Eudragit RL100 encapsulated gentamicin sulfate (E-G-S) nanoparticle of range 140 nm. It is 10-20 times more effective against E. coli biofilm-associated infections eradication than normal unentrapped G-S. Thus, Eudragit RL100 mediated drug delivery system provides a promising way to reduce the cost of treatment with a higher drug therapeutic index.},
}
@article {pmid31617725,
year = {2019},
author = {Altube, MJ and Martínez, MMB and Malheiros, B and Maffía, PC and Barbosa, LRS and Morilla, MJ and Romero, EL},
title = {Fast Biofilm Penetration and Anti-PAO1 Activity of Nebulized Azithromycin in Nanoarchaeosomes.},
journal = {Molecular pharmaceutics},
volume = {},
number = {},
pages = {},
doi = {10.1021/acs.molpharmaceut.9b00721},
pmid = {31617725},
issn = {1543-8392},
abstract = {Azithromycin (AZ) is a broad-spectrum antibiotic with anti-inflammatory and antiquorum sensing activity against biofilm forming bacteria such as Pseudomonas aeruginosa. AZ administered by oral or parenteral routes, however, neither efficiently accesses nor remains in therapeutic doses inside pulmonary biofilm depths. Instead, inhaled nanocarriers loaded with AZ may revert the problem of low accessibility and permanence of AZ into biofilms, enhancing its antimicrobial activity. The first inhalable nanovesicle formulation of AZ, nanoarchaeosome-AZ (nanoARC-AZ), is here presented. NanoARC prepared with total polar archaeolipids (TPAs), rich in 2,3-di-O-phytanyl-sn-glycero-1-phospho-(3'-sn-glycerol-1'-methylphosphate) (PGP-Me) from Halorubrum tebenquichense archaebacteria, consisted of ∼180 nm-diameter nanovesicles, loaded with 0.28 w/w AZ/TPA. NanoARC-AZ displayed lower minimal inhibitory concentration and minimal bactericidal concentration, higher preformed biofilm disruptive, and anti-PAO1 activity in biofilms than AZ. NanoARC penetrated and disrupted the structure of the PAO1 biofilm within only 1 h. Two milliliters of 15 μg/mL AZ nanoARC-AZ nebulized for 5 min rendered AZ doses compatible with in vitro antibacterial activity. The strong association between AZ and the nanoARC bilayer, combined with electrostatic attraction and trapping into perpendicular methyl groups of archaeolipids, as determined by Laurdan fluorescence anisotropy, generalized polarization, and small-angle X-ray scattering, was critical to stabilize during storage and endure shear forces of nebulization. NanoARC-AZ was noncytotoxic on A549 cells and human THP-1-derived macrophages, deserving further preclinical exploration as enhancers of AZ anti-PAO1 activity.},
}
@article {pmid31616604,
year = {2019},
author = {Chinnici, J and Yerke, L and Tsou, C and Busarajan, S and Mancuso, R and Sadhak, ND and Kim, J and Maddi, A},
title = {Candida albicans cell wall integrity transcription factors regulate polymicrobial biofilm formation with Streptococcus gordonii.},
journal = {PeerJ},
volume = {7},
number = {},
pages = {e7870},
pmid = {31616604},
issn = {2167-8359},
abstract = {Polymicrobial biofilms play important roles in oral and systemic infections. The oral plaque bacterium Streptococcus gordonii is known to attach to the hyphal cell wall of the fungus Candida albicans to form corn-cob like structures in biofilms. However, the role of C. albicans in formation of polymicrobial biofilms is not completely understood. The objective of this study was to determine the role of C. albicans transcription factors in regulation of polymicrobial biofilms and antibiotic tolerance of S. gordonii. The proteins secreted by C. albicans and S. gordonii in mixed planktonic cultures were determined using mass spectrometry. Antibiotic tolerance of S. gordonii to ampicillin and erythromycin was determined in mixed cultures and mixed biofilms with C. albicans. Additionally, biofilm formation of S. gordonii with C. albicans knock-out mutants of 45 transcription factors that affect cell wall integrity, filamentous growth and biofilm formation was determined. Furthermore, these mutants were also screened for antibiotic tolerance in mixed biofilms with S. gordonii. Analysis of secreted proteomes resulted in the identification of proteins being secreted exclusively in mixed cultures. Antibiotic testing showed that S. gordonii had significantly increased survival in mixed planktonic cultures with antibiotics as compared to single cultures. C. albicans mutants of transcription factors Sfl2, Brg1, Leu3, Cas5, Cta4, Tec1, Tup1, Rim101 and Efg1 were significantly affected in mixed biofilm formation. Also mixed biofilms of S. gordonii with mutants of C. albicans transcription factors, Tec1 and Sfl2, had significantly reduced antibiotic tolerance as compared to control cultures. Our data indicates that C. albicans may have an important role in mixed biofilm formation as well as antibiotic tolerance of S. gordonii in polymicrobial biofilms. C. albicans may play a facilitating role than being just an innocent bystander in oral biofilms and infections.},
}
@article {pmid31611856,
year = {2019},
author = {Peng, P and Baldry, M and Gless, BH and Bojer, MS and Espinosa-Gongora, C and Baig, SJ and Andersen, PS and Olsen, CA and Ingmer, H},
title = {Effect of Co-inhabiting Coagulase Negative Staphylococci on S. aureus agr Quorum Sensing, Host Factor Binding, and Biofilm Formation.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2212},
pmid = {31611856},
issn = {1664-302X},
abstract = {Staphylococcus aureus is a commensal colonizer of both humans and animals, but also an opportunistic pathogen responsible for a multitude of diseases. In recent years, colonization of pigs by methicillin resistant S. aureus has become a problem with increasing numbers of humans being infected by livestock strains. In S. aureus colonization and virulence factor expression is controlled by the agr quorum sensing system, which responds to and is activated by self-generated, autoinducing peptides (AIPs). AIPs are also produced by coagulase negative staphylococci (CoNS) commonly found as commensals in both humans and animals, and interestingly, some of these inhibit S. aureus agr activity. Here, we have addressed if cross-communication occurs between S. aureus and CoNS strains isolated from pig nares, and if so, how properties such as host factor binding and biofilm formation are affected. From 25 pig nasal swabs we obtained 54 staphylococcal CoNS isolates belonging to 8 different species. Of these, none were able to induce S. aureus agr as monitored by reporter gene fusions to agr regulated genes but a number of agr-inhibiting species were identified including Staphylococcus hyicus, Staphylococcus simulans, Staphylococcus arlettae, Staphylococcus lentus, and Staphylococcus chromogenes. After establishing that the inhibitory activity was mediated via AgrC, the receptor of AIPs, we synthesized selective AIPs to explore their effect on adhesion of S. aureus to fibronectin, a host factor involved in S. aureus colonization. Here, we found that the CoNS AIPs did not affect adhesion of S. aureus except for strain 8325-4. When individual CoNS strains were co-cultured together with S. aureus we observed variable degrees of biofilm formation which did not correlate with agr interactions. Our results show that multiple CoNS species can be isolated from pig nares and that the majority of these produce AIPs that inhibit S. aureus agr. Further they show that the consequences of the interactions between CoNS and S. aureus are complex and highly strain dependent.},
}
@article {pmid31611714,
year = {2019},
author = {Tam, A and Green, JEF and Balasuriya, S and Tek, EL and Gardner, JM and Sundstrom, JF and Jiranek, V and Binder, BJ},
title = {A thin-film extensional flow model for biofilm expansion by sliding motility.},
journal = {Proceedings. Mathematical, physical, and engineering sciences},
volume = {475},
number = {2229},
pages = {20190175},
pmid = {31611714},
issn = {1364-5021},
abstract = {In the presence of glycoproteins, bacterial and yeast biofilms are hypothesized to expand by sliding motility. This involves a sheet of cells spreading as a unit, facilitated by cell proliferation and weak adhesion to the substratum. In this paper, we derive an extensional flow model for biofilm expansion by sliding motility to test this hypothesis. We model the biofilm as a two-phase (living cells and an extracellular matrix) viscous fluid mixture, and model nutrient depletion and uptake from the substratum. Applying the thin-film approximation simplifies the model, and reduces it to one-dimensional axisymmetric form. Comparison with Saccharomyces cerevisiae mat formation experiments reveals good agreement between experimental expansion speed and numerical solutions to the model with O (1) parameters estimated from experiments. This confirms that sliding motility is a possible mechanism for yeast biofilm expansion. Having established the biological relevance of the model, we then demonstrate how the model parameters affect expansion speed, enabling us to predict biofilm expansion for different experimental conditions. Finally, we show that our model can explain the ridge formation observed in some biofilms. This is especially true if surface tension is low, as hypothesized for sliding motility.},
}
@article {pmid31610517,
year = {2019},
author = {Beni, AA and Esmaeili, A},
title = {Design and optimization of a new reactor based on biofilm-ceramic for industrial wastewater treatment.},
journal = {Environmental pollution (Barking, Essex : 1987)},
volume = {255},
number = {Pt 2},
pages = {113298},
doi = {10.1016/j.envpol.2019.113298},
pmid = {31610517},
issn = {1873-6424},
abstract = {A biofilm reactor was designed with flat ceramic substrates to remove Co(II), Ni(II) and Zn(II) from industrial wastewater. The ceramics were made of clay and nano-rubber with high mechanical resistance. The surface of the ceramic substrate was modified with neutral fiber and nano-hydroxyapatite. A uniform and stable biofilm mass of 320 g with 2 mm of thickness was produced on the modified ceramic after 3 d. The micro-organisms were identified in the biofilm by polymerase chain reaction (PCR) method. Functional groups of biofilms were identified with a Fourier transform infrared spectrometer (FT-IR). Experiments were designed by central composite design (CCD) using the responsive surface method (RSM). The biosorption process was optimized at pH = 5.8, temperature = 22 °C, feed flux of heavy metal wastewater = 225 ml, substrate flow = 30 ml, and retention time = 7.825 h. The kinetic data was analyzed by pseudo first-order and pseudo second-order kinetic models. Isotherm models and thermodynamic parameters were applied to describe the biosorption equilibrium data of the metal ions on the biofilm-ceramic. The maximum biosorption efficiency and capacity of heavy metal ions were about 72% and 57.21 mg, respectively.},
}
@article {pmid31609795,
year = {2019},
author = {Pai, AB and McGuire, MD and Davidge, KN and Dean, MC and Costello, GN and Souza, E and Mukherjee, S and Heung, M and Yevzlin, AS and Yessayan, LT},
title = {Lipoteichoic acid as a Potential Noninvasive Marker of Biofilm in Dialysis Access.},
journal = {ASAIO journal (American Society for Artificial Internal Organs : 1992)},
volume = {},
number = {},
pages = {},
doi = {10.1097/MAT.0000000000001091},
pmid = {31609795},
issn = {1538-943X},
abstract = {Tunneled central venous catheters (TCVCs) are colonized by Gram-positive organisms and form biofilm. Lipoteichoic acid (LTA) is a Gram-positive cell wall component that can be measured in serum. The purpose of this pilot study was to characterize LTA concentrations in hemodialysis (HD) patients with TCVCs compared to other access types and to evaluate biofilm morphology and microbiology in TCVCs removed by clinical decision. The study enrolled patients with TCVCs (18), grafts (19), and fistulas (18). Blood samples were collected before HD, at 30 minutes, 2 hours, and end of HD. Catheters removed by clinical decision were evaluated by scanning electron microscopy (SEM) for biofilm morphology, and portions of the catheter were cultured. LTA was detectable in all samples and concentrations increased significantly in all access types during HD (p < 0.05 for all comparisons). Patients with TCVCs that had a >30% increase in LTA concentration from baseline also had the greatest rate of increase (slope) compared to grafts and fistulas (p = 0.03 and p = 0.04, respectively). Catheters removed by clinical decision (n = 7) and examined by SEM had deposition of fibrin. Cultures revealed polymicrobial colonization. TCVCs had the highest rate of increase of LTA during HD. Further studies to determine the source of LTA in patients with AVG and AVF are warranted.},
}
@article {pmid31608256,
year = {2019},
author = {Jwa, SK},
title = {Efficacy of Moringa oleifera Leaf Extracts against Cariogenic Biofilm.},
journal = {Preventive nutrition and food science},
volume = {24},
number = {3},
pages = {308-312},
pmid = {31608256},
issn = {2287-1098},
abstract = {Moringa oleifera leaves are beneficial for human health. Dental caries is closely related with cariogenic biofilm, which is an oral biofilm containing a high proportion of Streptococcus mutans. The purpose of this study was to investigate the antimicrobial effects of the M. oleifera leaf extracts on S. mutans and formation of cariogenic biofilm. Extract from M. oleifera leaves was derived using distilled water (DW) and ethyl alcohol (EtOH). S. mutans susceptibility assays were performed for each extract. Cariogenic biofilm was formed with or without DW and EtOH extract, and cariogenic biofilm was treated with both extracts. The biofilm was observed by confocal laser microscopy, and the bacteria in the biofilm were counted. Both extracts showed antimicrobial activity against S. mutans and inhibited formation of cariogenic biofilm. The EtOH extracts exhibited anti-biofilm activity. M. oleifera leaves may be potential candidates to prevent dental caries.},
}
@article {pmid31608016,
year = {2019},
author = {Catão, ECP and Pollet, T and Misson, B and Garnier, C and Ghiglione, JF and Barry-Martinet, R and Maintenay, M and Bressy, C and Briand, JF},
title = {Shear Stress as a Major Driver of Marine Biofilm Communities in the NW Mediterranean Sea.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1768},
pmid = {31608016},
issn = {1664-302X},
abstract = {While marine biofilms depend on environmental conditions and substrate, little is known about the influence of hydrodynamic forces. We tested different immersion modes (dynamic, cyclic and static) in Toulon Bay (north-western Mediterranean Sea; NWMS). The static mode was also compared between Toulon and Banyuls Bays. In addition, different artificial surfaces designed to hamper cell attachment (self-polishing coating: SPC; and fouling-release coating: FRC) were compared to inert plastic. Prokaryotic community composition was affected by immersion mode, surface characteristics and site. Rhodobacteriaceae and Flavobacteriaceae dominated the biofilm community structure, with distinct genera according to surface type or immersion mode. Cell density increased with time, greatly limited by hydrodynamic forces, and supposed to delay biofilm maturation. After 1 year, a significant impact of shear stress on the taxonomic structure of the prokaryotic community developed on each surface type was observed. When surfaces contained no biocides, roughness and wettability shaped prokaryotic community structure, which was not enhanced by shear stress. Conversely, the biocidal effect of SPC surfaces, already major in static immersion mode, was amplified by the 15 knots speed. The biofilm community on SPC was 60% dissimilar to the biofilm on the other surfaces and was distinctly colonized by Sphingomonadaceae ((Alter)Erythrobacter). At Banyuls, prokaryotic community structures were more similar between the four surfaces tested than at Toulon, due possibly to a masking effect of environmental constraints, especially hydrodynamic, which was greater than in Toulon. Finally, predicted functions such as cell adhesion confirmed some of the hypotheses drawn regarding biofilm formation over the artificial surfaces tested here.},
}
@article {pmid31607570,
year = {2019},
author = {Liao, CH and Chen, CS and Chen, YC and Jiang, NE and Farn, CJ and Shen, YS and Hsu, ML and Chang, CH},
title = {Vancomycin-loaded oxidized hyaluronic acid and adipic acid dihydrazide hydrogel: Bio-compatibility, drug release, antimicrobial activity, and biofilm model.},
journal = {Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.jmii.2019.08.008},
pmid = {31607570},
issn = {1995-9133},
abstract = {BACKGROUND: Prosthesis infection is a difficult-to-treat situation. Hydrogel is a novel biomaterial, which can be applied by simply spraying or by coating on implants before surgery and can be easily mixed with antibiotics.<br><br>METHODS: In order to evaluate the potential use of antibiotic-loaded hydrogel, we incorporated vancomycin into oxidized hyaluronic acid (HA) and adipic acid dihydrazide and evaluated the drug release and antimicrobial activity against methicillin-resistant Staphylococcus aureus (ATCC 29213).<br><br>RESULTS: The average release percentage of vancomycin on day 3 was about 86%. The antibiotic-loaded gel was biocompatible with mesenchymal stem cell, MC3T3, and L929 cell lines. The in vitro inhibition zones of vancomycin-loaded hydrogel [500X minimal inhibition concentration (MIC), 50X MIC, 10X MIC, and blank hydrogel] were 21, 13, 9, and 5 mm, respectively. In the Ti6Al4V implant biofilm model, 0.01-1% vancomycin-loaded gel exhibited significant anti-biofilm activity, measured by the MTT assay.<br><br>CONCLUSIONS: Vancomycin could be loaded onto oxidized HA and adipic acid dihydrazide, which exhibited excellent drug release and in vitro antimicrobial activity with minimal cell toxicity.},
}
@article {pmid31605761,
year = {2019},
author = {Parai, D and Banerjee, M and Dey, P and Mukherjee, SK},
title = {Reserpine attenuates biofilm formation and virulence of Staphylococcus aureus.},
journal = {Microbial pathogenesis},
volume = {138},
number = {},
pages = {103790},
doi = {10.1016/j.micpath.2019.103790},
pmid = {31605761},
issn = {1096-1208},
abstract = {This study investigated the effects of reserpine, the main bioactive compound of Rauwolfia serpentina, on biofilm formation and biofilm-associated virulence factors production in a Gram-positive pathogen, Staphylococcus aureus. Crystal violet assay, MTT assay, Congo red binding, CLSM studies were performed to assess the antibiofilm activity. Molecular docking was performed to explain the possible mode of action, catheter model was used to evaluate its application potential and the combinatorial study was performed in search of an improved therapeutic formulation. Reserpine affected biofilm formation, EPS production, biofilm cell viability and virulence factor production. It could eradicate 72.7% biofilm at ½ × MIC dose and could also stop the metabolic activity of 50.6% bacterial cells in a biofilm. Staphylococcus aureus biofilm- and virulence-regulatory proteins like AgrA, AtlE, Bap, IcaA, SarA and SasG were found to interact with reserpine which might lead to the attenuation of its pathogenicity. Reserpine along with other commercial antibiotics could generate a hightened antibiofilm response, and also eradicated a good percentage of bacterial biofilm from a urinary catheter model. These findings suggested reserpine as a good alternative entity to generate new improved therapeutic formulations.},
}
@article {pmid31605708,
year = {2019},
author = {Dai, L and Wu, TQ and Xiong, YS and Ni, HB and Ding, Y and Zhang, WC and Chu, SP and Ju, SQ and Yu, J},
title = {Ibuprofen-mediated potential inhibition of biofilm development and quorum sensing in Pseudomonas aeruginosa.},
journal = {Life sciences},
volume = {237},
number = {},
pages = {116947},
doi = {10.1016/j.lfs.2019.116947},
pmid = {31605708},
issn = {1879-0631},
mesh = {Anti-Inflammatory Agents, Non-Steroidal/pharmacology ; Bacterial Proteins/*genetics ; Biofilms/drug effects/*growth &amp; development ; Gene Expression Regulation, Bacterial/*drug effects ; Humans ; Ibuprofen/*pharmacology ; Pseudomonas Infections/drug therapy/microbiology ; Pseudomonas aeruginosa/drug effects/*genetics/growth &amp; development ; Quorum Sensing/*drug effects ; Virulence Factors/*genetics ; },
abstract = {AIMS: Pseudomonas aeruginosa is one of the leading causes of opportunistic and hospital-acquired infections worldwide, which is frequently linked with clinical treatment difficulties. Ibuprofen, a widely used non-steroidal anti-inflammatory drug, has been previously reported to exert antimicrobial activity with the specific mechanism. We hypothesized that inhibition of P. aeruginosa with ibuprofen is involved in the quorum sensing (QS) systems.<br><br>MAIN METHODS: CFU was utilized to assessed the growth condition of P. aeruginosa. Crystal violent staining and acridine orange staining was used to evaluate the biofilm formation and adherence activity. The detection of QS virulence factors such as pyocyanin, elastase, protease, and rhamnolipids were applied to investigation the anti-QS activity of ibuprofen against P. aeruginosa. The production of 3-oxo-C12-HSL and C4-HSL was confirmed by liquid chromatography/mass spectrometry analysis. qRT-PCR was used to identify the QS-related gene expression. Furthermore, we explored the binding effects between ibuprofen and QS-associated proteins with molecular docking.<br><br>KEY FINDINGS: Ibuprofen inhibits P. aeruginosa biofilm formation and adherence activity. And the inhibitory effects of ibuprofen on C4-HSL levels were concentration-dependent (p < 0.05), while it has no effect on 3-oxo-C12-HSL. Moreover, ibuprofen attenuates the production of virulence factors in P. aeruginosa (p < 0.05). In addition, the genes of QS system were decreased after the ibuprofen treatment (p < 0.05). Of note, ibuprofen was binding with LuxR, LasR, LasI, and RhlR at high binding scores.<br><br>SIGNIFICANCE: The antibiofilm and anti-QS activity of ibuprofen suggest that it can be a candidate drug for the treatment of clinical infections with P. aeruginosa.},
}
@article {pmid31603038,
year = {2019},
author = {Mugge, RL and Lee, JS and Brown, TT and Hamdan, LJ},
title = {Marine biofilm bacterial community response and carbon steel loss following Deepwater Horizon spill contaminant exposure.},
journal = {Biofouling},
volume = {35},
number = {8},
pages = {870-882},
doi = {10.1080/08927014.2019.1673377},
pmid = {31603038},
issn = {1029-2454},
abstract = {Steel marine structures provide foci of biodiversity when they develop into artificial reefs. Development begins with deposition of a biofilm. The effects of contaminants from oil spills on biofilm microbiomes, microbially-induced corrosion (MIC) and metal loss may impact preservation of marine metal structures. A microcosm experiment exposed biofilms on carbon steel disks (CSDs) to crude oil, dispersant, and dispersed oil to address their impacts on bacterial composition and metal loss and pitting. Biofilm diversity increased over time in all exposures. Community composition in dispersant and dispersed oil treatments deviated from the controls for the duration of a 12-week experiment. As biofilms matured, Pseudomonadaceae increased while Rhodobacteraceae decreased in abundance in dispersed oil treatments compared to the controls and dispersant treatments. Greatest mass loss and deepest pitting on CSDs were observed in dispersed oil treatments, suggesting impacts manifest as a consequence of increased MIC potential on carbon steel.},
}
@article {pmid31602310,
year = {2019},
author = {Rupel, K and Zupin, L and Ottaviani, G and Bertani, I and Martinelli, V and Porrelli, D and Vodret, S and Vuerich, R and Passos da Silva, D and Bussani, R and Crovella, S and Parsek, M and Venturi, V and Di Lenarda, R and Biasotto, M and Zacchigna, S},
title = {Blue laser light inhibits biofilm formation in vitro and in vivo by inducing oxidative stress.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {29},
pmid = {31602310},
issn = {2055-5008},
abstract = {Resolution of bacterial infections is often hampered by both resistance to conventional antibiotic therapy and hiding of bacterial cells inside biofilms, warranting the development of innovative therapeutic strategies. Here, we report the efficacy of blue laser light in eradicating Pseudomonas aeruginosa cells, grown in planktonic state, agar plates and mature biofilms, both in vitro and in vivo, with minimal toxicity to mammalian cells and tissues. Results obtained using knock-out mutants point to oxidative stress as a relevant mechanism by which blue laser light exerts its anti-microbial effect. Finally, the therapeutic potential is confirmed in a mouse model of skin wound infection. Collectively, these data set blue laser phototherapy as an innovative approach to inhibit bacterial growth and biofilm formation, and thus as a realistic treatment option for superinfected wounds.},
}
@article {pmid31600988,
year = {2019},
author = {Bardhan, T and Chakraborty, M and Bhattacharjee, B},
title = {Bactericidal Activity of Lactic Acid against Clinical, Carbapenem-Hydrolyzing, Multi-Drug-Resistant Klebsiella pneumoniae Planktonic and Biofilm-Forming Cells.},
journal = {Antibiotics (Basel, Switzerland)},
volume = {8},
number = {4},
pages = {},
doi = {10.3390/antibiotics8040181},
pmid = {31600988},
issn = {2079-6382},
support = {Ramanujan Fellowship; SB/S2/RJN-013/2014//Science and Engineering Research Board/ ; },
abstract = {: Carbapenem resistant Klebsiella pneumoniae has been highlighted to be a critical pathogen by the World Health Organization. The objectives of this study were to assess the efficacy of lactic acid (LA) against planktonic cells and biofilms formed by carbapenem-hydrolyzing K. pneumoniae isolates obtained from the nares of preterm neonates. Time-kill assays with graded percentages of (v/v) LA in water were initially carried out against planktonic cells of a meropenem (MRP)-resistant K. pneumoniae isolate, JNM11.C4. The efficacy parameters such as optimal incubation time and minimum inhibitory concentration were determined by comparing colony-forming unit counts (log(10)CFU). Scanning electron microscopy was used to visualize cell damage. Likewise, JNM11.C4 biofilms were treated with graded series of (v/v) LA. Six carbapenem-hydrolyzing isolates were next used to validate the results. A reduction of 3.6 ± 0.6 log(10) CFU/mL in JNM11.C4 planktonic cells and >3 ± 0.03log(10) CFU/mL in biofilm-forming cells were observed using 0.225% and 2% LA, respectively, after three hours. Similar decreases in viable cell-counts were observed both in the case of planktonic (˃3.6 ± 0.3log(10) CFU/mL) and biofilm-forming cells (3.8 ± 0.3log(10) CFU/mL) across all the six clinical isolates. These results indicate that LA is an effective antimicrobial against planktonic carbapenem-hydrolyzing K. pneumoniae cells and biofilms.},
}
@article {pmid31599377,
year = {2019},
author = {Bakraoui, M and Hazzi, M and Karouach, F and Ouhammou, B and El Bari, H},
title = {Experimental biogas production from recycled pulp and paper wastewater by biofilm technology.},
journal = {Biotechnology letters},
volume = {41},
number = {11},
pages = {1299-1307},
doi = {10.1007/s10529-019-02735-w},
pmid = {31599377},
issn = {1573-6776},
support = {413223920433//University Ibn Tofail/ ; },
abstract = {OBJECTIVE: The main objective of this study is the evaluation of RPPW anaerobic digestion feasibility at laboratory scale under Mesophilic condition. The experiment is conducted using a two-stage biofilm digester of 5 L capacity with mobile support material.<br><br>RESULTS: Anaerobic treatment of wastewater from recycled pulp and paper industry in Morocco was tested using a laboratory-scale anaerobic biofilm digester that operated under mesophilic conditions over a 70-day. Chemical oxygen demand (COD) efficiency, volatile and total solid (VS, TS) elimination of the substrate during the process were: 78%, 52% and 48% respectively. The system was stable throughout its operating cycle with an optimum pH (7.24), alkalinity (1750 mg CaCO3/L) and a volatile fatty acid value (760 mg/L). The experimental daily biogas production measured reaches a value of 5 L/day with a composition of 71% methane, 27.6% carbon dioxide, 0.2 oxygen and 7713 ppm of the H2S. The study results show that the anaerobic biofilm reactor is a suitable technique for recycled pulp and paper wastewater (RPPW) treatment. The reactor shows high performances in terms of process stability, removal efficiency (> 70%) and biogas production.<br><br>CONCLUSION: Anaerobic digestion is an efficient waste treatment technology that uses natural anaerobic decomposition to reduce the volume of waste while producing biogas. However, research is needed to strengthen microbial metabolism, biochemistry and the functioning of the rector to improve biogas production. The RPPW AD experiment with biofilm digester technology was stable throughout the operation period. The digester knows an overloaded in the last phase of the experiment which leads to an inhibition of biogas production.},
}
@article {pmid31599128,
year = {2019},
author = {Turner, ME and Huynh, K and Carney, OV and Gross, D and Carroll, RK and Ahn, SJ and Rice, KC},
title = {Genomic instability of TnSMU2 contributes to Streptococcus mutans biofilm development and competence in a cidB mutant.},
journal = {MicrobiologyOpen},
volume = {8},
number = {12},
pages = {e934},
pmid = {31599128},
issn = {2045-8827},
support = {//University of Florida/ ; 1161177//National Science Foundation/ ; DE025237/DE/NIDCR NIH HHS/United States ; DE025237/NH/NIH HHS/United States ; R01 DE025237/DE/NIDCR NIH HHS/United States ; },
abstract = {Streptococcus mutans is a key pathogenic bacterium in the oral cavity and a primary contributor to dental caries. The S. mutans Cid/Lrg system likely contributes to tolerating stresses encountered in this environment as cid and/or lrg mutants exhibit altered oxidative stress sensitivity, genetic competence, and biofilm phenotypes. It was recently noted that the cidB mutant had two stable colony morphologies: a &quot;rough&quot; phenotype (similar to wild type) and a &quot;smooth&quot; phenotype. In our previously published work, the cidB rough mutant exhibited increased sensitivity to oxidative stress, and RNAseq identified widespread transcriptomic changes in central carbon metabolism and oxidative stress response genes. In this current report, we conducted Illumina-based genome resequencing of wild type, cidB rough, and cidB smooth mutants and compared their resistance to oxidative and acid stress, biofilm formation, and competence phenotypes. Both cidB mutants exhibited comparable aerobic growth inhibition on agar plates, during planktonic growth, and in the presence of 1 mM hydrogen peroxide. The cidB smooth mutant displayed a significant competence defect in BHI, which was rescuable by synthetic CSP. Both cidB mutants also displayed reduced XIP-mediated competence, although this reduction was more pronounced in the cidB smooth mutant. Anaerobic biofilms of the cidB smooth mutant displayed increased propidium iodide staining, but corresponding biofilm CFU data suggest this phenotype is due to cell damage and not increased cell death. The cidB rough anaerobic biofilms showed altered structure relative to wild type (reduced biomass and average thickness) which correlated with decreased CFU counts. Sequencing data revealed that the cidB smooth mutant has a unique &quot;loss of read coverage&quot; of ~78 kb of DNA, corresponding to the genomic island TnSMU2 and genes flanking its 3' end. It is therefore likely that the unique biofilm and competence phenotypes of the cidB smooth mutant are related to its genomic changes in this region.},
}
@article {pmid31594958,
year = {2019},
author = {Liu, W and Tian, XQ and Wei, JW and Ding, LL and Qian, W and Liu, Z and Wang, FF},
title = {Author Correction: BsmR degrades c-di-GMP to modulate biofilm formation of nosocomial pathogen Stenotrophomonas maltophilia.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {14778},
doi = {10.1038/s41598-019-43380-7},
pmid = {31594958},
issn = {2045-2322},
abstract = {A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.},
}
@article {pmid31593452,
year = {2019},
author = {Chen, H and Luo, J and Liu, S and Yuan, Z and Guo, J},
title = {Microbial Methane Conversion to Short-Chain Fatty Acids Using Various Electron Acceptors in Membrane Biofilm Reactors.},
journal = {Environmental science &amp; technology},
volume = {53},
number = {21},
pages = {12846-12855},
doi = {10.1021/acs.est.8b06767},
pmid = {31593452},
issn = {1520-5851},
mesh = {Biofilms ; Bioreactors ; *Electrons ; Fatty Acids, Volatile ; Membranes ; *Methane ; },
abstract = {Given our vast methane reserves and the forecasted shortage of crude oil in the not too distant future, the conversion of methane into value-added liquid chemicals or fuels would be beneficial. The generated chemicals or fuels could augment the petroleum-dominated chemical market, and also satisfy the increasing demand for transportation fuels. While methane bioconversion to liquid chemicals has just been reported recently, there is limited understanding of the process. This study aims to clarify the potential electron acceptors that could support the process. Here we operated four membrane biofilm reactors (MBfRs) fed with nitrate, nitrite, oxygen at a relatively low rate, and oxygen at a relatively high rate, respectively, to study if they can support methane bioconversion to short-chain fatty acids (SCFAs) and the associated microbiological features. All tested electron acceptors facilitated methane bioconversion to SCFAs (ranging from 1.1 to 36.7 mg acetate L-1 d-1, or 3.4 to 114.6 mg acetate d-1 m-2 of biofilm). The carbon efficiency was estimated to be 7.9 ± 1.4% to 148.5 ± 1.3%, with an efficiency higher than 100%, suggesting the assimilation of other carbon, very likely CO2, into the products. A low oxygen supply rate of 46.4 ± 2.3 mg O2 d-1 m-2 was found to be the most favorable among all the electron conditions provided according to the SCFAs production rate and also the carbon utilization efficiency. Microbial characterization revealed that completely different communities evolved in the respective reactors, suggesting diverse microbial pathways exist for methane bioconversion into value-added chemicals.},
}
@article {pmid31590609,
year = {2020},
author = {Diaz, PI and Valm, AM},
title = {Microbial Interactions in Oral Communities Mediate Emergent Biofilm Properties.},
journal = {Journal of dental research},
volume = {99},
number = {1},
pages = {18-25},
doi = {10.1177/0022034519880157},
pmid = {31590609},
issn = {1544-0591},
support = {R03 DE028042/DE/NIDCR NIH HHS/United States ; },
abstract = {Oral microbial communities are extraordinarily complex in taxonomic composition and comprise interdependent biological systems. The bacteria, archaea, fungi, and viruses that thrive within these communities engage in extensive cell-cell interactions, which are both beneficial and antagonistic. Direct physical interactions among individual cells mediate large-scale architectural biofilm arrangements and provide spatial proximity for chemical communication and metabolic cooperation. In this review, we summarize recent work in identifying specific molecular components that mediate cell-cell interactions and describe metabolic interactions, such as cross-feeding and exchange of electron acceptors and small molecules, that modify the growth and virulence of individual species. We argue, however, that although pairwise interaction models have provided useful information, complex community-like systems are needed to study the properties of oral communities. The networks of multiple synergistic and antagonistic interactions within oral biofilms give rise to the emergent properties of persistence, stability, and long-range spatial structure, with these properties mediating the dysbiotic transitions from health to oral diseases. A better understanding of the fundamental properties of interspecies networks will lead to the development of effective strategies to manipulate oral communities.},
}
@article {pmid31589910,
year = {2019},
author = {Miryala, S and Makala, H and Yadavali, SP and Venkatasubramanian, U and Subbaiah, N and Srinandan, CS},
title = {Disperse red 15 (DR15) impedes biofilm formation of uropathogenic Escherichia coli.},
journal = {Microbial pathogenesis},
volume = {138},
number = {},
pages = {103772},
doi = {10.1016/j.micpath.2019.103772},
pmid = {31589910},
issn = {1096-1208},
abstract = {Catheter associated urinary tract infection (CAUTI) is a highly prevalent hospital-acquired infection that is predominantly caused by uropathogenic Escherichia coli (UPEC). It adheres on catheter surface using type I pili as the initial step of pathogenesis that progresses to form biofilm. In this study, potential inhibitors against FimH adhesin of type I pili were screened computationally that yielded ten compounds. These were further validated in vitro against adhesion and biofilm formation. The compounds, 1-Amino-4-hydroxyanthraquinone (Disperse Red 15 or DR15) and 4-(4'-chloro-4-biphenylylsulfonylamino) benzoic acid (CB1) impaired adhesion and biofilm formation without inhibiting the planktonic growth. Also, both compounds inhibited cell assemblages like autoaggregation and swarming motility by unknown mechanisms. DR15 was further derivatised into N-(4-hydroxy-9,10-dioxo-9,10-dihydroanthracen-1-yl) undec-10-enamide that self-assembled with linseed oil, which was used as the coating material on urinary Foley catheters. The thin-film coating on the catheter did not leach when incubated in artificial urine and effectively restricted biofilm formation of UPEC. Altogether, the thin-film coating of urinary catheter with DR15 inhibited biofilm formation of UPEC and this application could potentially help to reduce CAUTI incidents in healthcare facilities.},
}
@article {pmid31589311,
year = {2019},
author = {Silva, MOD and Pernthaler, J},
title = {Priming of microcystin degradation in carbon-amended membrane biofilm communities is promoted by oxygen-limited conditions.},
journal = {FEMS microbiology ecology},
volume = {95},
number = {11},
pages = {},
pmid = {31589311},
issn = {1574-6941},
abstract = {Microbial biofilms are an important element of gravity-driven membrane (GDM) filtration systems for decentralized drinking water production. Mature biofilms fed with biomass from the toxic cyanobacterium Microcystis aeruginosa efficiently remove the cyanotoxin microcystin (MC). MC degradation can be 'primed' by prior addition of biomass from a non-toxic M. aeruginosa strain. Increased proportions of bacteria with an anaerobic metabolism in M. aeruginosa-fed biofilms suggest that this 'priming' could be due to higher productivity and the resulting changes in habitat conditions. We, therefore, investigated GDM systems amended with the biomass of toxic (WT) or non-toxic (MUT) M. aeruginosa strains, of diatoms (DT), or with starch solution (ST). After 25 days, these treatments were changed to receiving toxic cyanobacterial biomass. MC degradation established significantly more rapidly in MUT and ST than in DT. Oxygen measurements suggested that this was due to oxygen-limited conditions in MUT and ST already prevailing before addition of MC-containing biomass. Moreover, the microbial communities in the initial ST biofilms featured high proportions of facultative anaerobic taxa, whereas aerobes dominated in DT biofilms. Thus, the 'priming' of MC degradation in mature GDM biofilms seems to be related to the prior establishment of oxygen-limited conditions mediated by higher productivity.},
}
@article {pmid31589240,
year = {2019},
author = {Favre, L and Ortalo-Magné, A and Kerloch, L and Pichereaux, C and Misson, B and Briand, JF and Garnier, C and Culioli, G},
title = {Metabolomic and proteomic changes induced by growth inhibitory concentrations of copper in the biofilm-forming marine bacterium Pseudoalteromonas lipolytica.},
journal = {Metallomics : integrated biometal science},
volume = {11},
number = {11},
pages = {1887-1899},
doi = {10.1039/c9mt00184k},
pmid = {31589240},
issn = {1756-591X},
abstract = {Copper is an essential element for living cells but this metal is present in some marine environments at such high concentrations that it can be toxic for numerous organisms. In polluted areas, marine organisms may develop specific adaptive responses to prevent cell damage. To investigate the influence of copper on the metabolism of a single organism, a dual approach combining metabolomics and proteomics was undertaken on the biofilm-forming bacterial strain Pseudoalteromonas lipolytica TC8. In order to highlight differential adaptation according to the phenotype, the response of P. lipolytica TC8 to copper stress was studied in planktonic and biofilm culture modes under growth inhibitory copper concentrations. As expected, copper exposure led to the induction of defense and detoxification mechanisms. Specific metabolite and protein profiles were thus observed in each condition (planktonic vs. biofilm and control vs. copper-treated cultures). Copper exposure seems to induce drastic changes in the lipid composition of the bacterial cell membrane and to modulate the abundance of proteins functionally known to be involved in copper cell homeostasis in both planktonic and biofilm culture modes. Much more proteins differentially expressed after copper treatment were observed in biofilms than in planktonic cells, which could indicate a more heterogeneous response of biofilm cells to this metallic stress.},
}
@article {pmid31586764,
year = {2019},
author = {Liu, X and Zhuo, S and Jing, X and Yuan, Y and Rensing, C and Zhou, S},
title = {Flagella act as Geobacter biofilm scaffolds to stabilize biofilm and facilitate extracellular electron transfer.},
journal = {Biosensors &amp; bioelectronics},
volume = {146},
number = {},
pages = {111748},
doi = {10.1016/j.bios.2019.111748},
pmid = {31586764},
issn = {1873-4235},
abstract = {Flagella are widely expressed in electroactive biofilms; however, their actual role is unknown. To understand the role of flagella, two Geobacter sulfurreducens strains (KN400 and PCA, with and without flagella, respectively) were selected. We restored flagellum expression in trans in strain PCA and prevented flagellum expression in strain KN400. Electrochemical results showed that flagellum restoration in strain PCA promoted current generation, while flagellum deletion in strain KN400 impaired current production. However, the expression of conductive pili and outer surface c-type cytochromes was not affected. Further microscopic analyses demonstrated that flagella promoted the formation of thicker biofilms and served as biofilm matrix scaffolds to accommodate more extracellular cytochromes with an orderly arrangement, which increased the electron diffusion rate within the biofilm. Our findings reveal an unprecedented structural role for flagella in stabilizing electroactive biofilms and highlight the importance of cytochromes in electron transfer across biofilms, which will deepen our understanding of biofilm conductivity.},
}
@article {pmid31586475,
year = {2019},
author = {Shi, N and Gao, Y and Yin, D and Song, Y and Kang, J and Li, X and Zhang, Z and Feng, X and Duan, J},
title = {The effect of the sub-minimal inhibitory concentration and the concentrations within resistant mutation window of ciprofloxacin on MIC, swimming motility and biofilm formation of Pseudomonas aeruginosa.},
journal = {Microbial pathogenesis},
volume = {137},
number = {},
pages = {103765},
doi = {10.1016/j.micpath.2019.103765},
pmid = {31586475},
issn = {1096-1208},
abstract = {OBJECTIVE: To explore the effect of sub-minimal inhibitory concentration (sub-MIC) and concentrations within resistant mutation window (MSW) of ciprofloxacin (CIP) on minimal inhibitory concentration (MIC), swimming motility and biofilm formation of Pseudomonas aeruginosa, and also to investigate the correlation between swimming motility and genes expression of lasI, lasR, rhlI, rhlR and pqsR.<br><br>METHODS: The collected strains were incubated under four different concentrations for 5 days. The MIC and mutant prevention concentration (MPC) were measured by the agar dilution method. The diameter of turbid cycle was used to signify the swimming motility. The biofilm formation was measured by the crystal violet stain method. The genes expression of lasI, lasR, rhlI, rhlR and pqsR were measured by RT-PCR.<br><br>RESULTS: A total of 11 P. aeruginosa which sensitive to CIP were collected. The incubation within concentrations of MSW made MICs to CIP increased more obviously than under sub-MIC (P < 0.05). The swimming motility showed a trend of being inhibited first and then promoted over time under sub-MIC (P < 0.05), whereas, it was promoted under concentrations within MSW. The biofilm formation was significantly promoted under the concentration of 4×MIC (P < 0.05). Under sub-MIC, the genes expression of rhlR and pqsR had a middle level positive correlation with the promotion of the swimming motility (P < 0.05, r = 0.788 and P < 0.05, r = 0.652, respectively).<br><br>CONCLUSIONS: Under the concentration of sub-MIC (0.5×MIC) and the concentrations within MSW (1×MIC, 2×MIC and 4×MIC), the effect of CIP on MICs, swimming motility and biofilm formation of P.aeruginosa was quite different. The genes expression of rhlR and pqsR had a middle level positive correlation with the promotion of the swimming motility.},
}
@article {pmid31585061,
year = {2019},
author = {Thompson, AF and English, EL and Nock, AM and Willsey, GG and Eckstrom, K and Cairns, B and Bavelock, M and Tighe, SW and Foote, A and Shulman, H and Pericleous, A and Gupta, S and Kadouri, DE and Wargo, MJ},
title = {Characterizing species interactions that contribute to biofilm formation in a multispecies model of a potable water bacterial community.},
journal = {Microbiology (Reading, England)},
volume = {},
number = {},
pages = {},
doi = {10.1099/mic.0.000849},
pmid = {31585061},
issn = {1465-2080},
support = {P20 GM103449/GM/NIGMS NIH HHS/United States ; T32 HL076122/HL/NHLBI NIH HHS/United States ; },
abstract = {Microbial biofilms are ubiquitous in drinking water systems, yet our understanding of drinking water biofilms lags behind our understanding of those in other environments. Here, a six-member model bacterial community was used to identify the interactions and individual contributions of each species to community biofilm formation. These bacteria were isolated from the International Space Station potable water system and include Cupriavidus metallidurans, Chryseobacterium gleum, Ralstonia insidiosa, Ralstonia pickettii, Methylorubrum (Methylobacterium) populi and Sphingomonas paucimobilis, but all six species are common members of terrestrial potable water systems. Using reconstituted assemblages, from pairs to all 6 members, community biofilm formation was observed to be robust to the absence of any single species and only removal of the C. gleum/S. paucimobilis pair, out of all 15 possible 2-species subtractions, led to loss of community biofilm formation. In conjunction with these findings, dual-species biofilm formation assays supported the view that the contribution of C. gleum to community biofilm formation was dependent on synergistic biofilm formation with either R. insidiosa or C. metallidurans. These data support a model of multiple, partially redundant species interactions to generate robustness in biofilm formation. A bacteriophage and multiple predatory bacteria were used to test the resilience of the community to the removal of individual members in situ, but the combination of precise and substantial depletion of a single target species was not achievable. We propose that this assemblage can be used as a tractable model to understand the molecular bases of the interactions described here and to decipher other functions of drinking water biofilms.},
}
@article {pmid31585041,
year = {2019},
author = {Xi, Y and Wang, Y and Gao, J and Xiao, Y and Du, J},
title = {Dual Corona Vesicles with Intrinsic Antibacterial and Enhanced Antibiotic Delivery Capabilities for Effective Treatment of Biofilm-Induced Periodontitis.},
journal = {ACS nano},
volume = {13},
number = {12},
pages = {13645-13657},
doi = {10.1021/acsnano.9b03237},
pmid = {31585041},
issn = {1936-086X},
abstract = {Periodontitis is a common disease caused by plaque biofilms, which are important pathogenic factors of many diseases and may be eradicated by antibiotic therapy. However, low-dose antibiotic therapy is a complicated challenge for eradicating biofilms as hundreds (even thousands) of times higher concentrations of antibiotics are needed than killing planktonic bacteria. Polymer vesicles may solve these problems via effective antibiotic delivery into biofilms, but traditional single corona vesicles lack the multifunctionalities essential for biofilm eradication. In this paper, we aim to effectively treat biofilm-induced periodontitis using much lower concentrations of antibiotics than traditional antibiotic therapy by designing a multifunctional dual corona vesicle with intrinsic antibacterial and enhanced antibiotic delivery capabilities. This vesicle is co-assembled from two block copolymers, poly(ε-caprolactone)-block-poly(lysine-stat-phenylalanine) [PCL-b-P(Lys-stat-Phe)] and poly(ethylene oxide)-block-poly(ε-caprolactone) [PEO-b-PCL]. Both PEO and P(Lys-stat-Phe) coronas have their specific functions: PEO endows vesicles with protein repelling ability to penetrate extracellular polymeric substances in biofilms (&quot;stealthy&quot; coronas), whereas P(Lys-stat-Phe) provides vesicles with positive charges and broad spectrum intrinsic antibacterial activity. As a result, the dosage of antibiotics can be reduced by 50% when encapsulated in the dual corona vesicles to eradicate Escherichia coli or Staphylococcus aureus biofilms. Furthermore, effective in vivo treatment has been achieved from a rat periodontitis model, as confirmed by significantly reduced dental plaque, and alleviated inflammation. Overall, this &quot;stealthy&quot; and antibacterial dual corona vesicle demonstrates a fresh insight for improving the antibiofilm efficiency of antibiotics and combating the serious threat of biofilm-associated diseases.},
}
@article {pmid31584765,
year = {2019},
author = {García, A and Martínez, C and Juárez, RI and Téllez, R and Paredes, MA and Herrera, MDR and Giono, S},
title = {Methicillin resistance and biofilm production in clinical isolates of Staphylococcus aureus and coagulase-negative Staphylococcus in México.},
journal = {Biomedica : revista del Instituto Nacional de Salud},
volume = {39},
number = {3},
pages = {513-523},
doi = {10.7705/biomedica.4131},
pmid = {31584765},
issn = {0120-4157},
}
@article {pmid31584713,
year = {2019},
author = {Soares Dos Santos, DM and Braga, AS and Rizk, M and Wiegand, A and Magalhães, AC},
title = {Comparison between micro-computed tomography and transverse microradiography of sound dentine treated with fluorides and demineralized by microcosm biofilm.},
journal = {European journal of oral sciences},
volume = {127},
number = {6},
pages = {508-514},
doi = {10.1111/eos.12656},
pmid = {31584713},
issn = {1600-0722},
support = {MWK INST 1525/39-1 FUGG//Deutsche Forschungsgemeinschaft/ ; 2017/13386-5//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 2017/00556-0//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; },
abstract = {The study aimed to apply micro-computed tomography (micro-CT) and transverse microradiography (TMR) to measure dentine demineralization and to test the preventive effect of titanium tetrafluoride (TiF4) under microcosm biofilm. Sound dentine specimens from bovine root were treated for 6 h with: (i) 4.0% titanium tetrafluoride (TiF4) varnish [pH 1.0, 2.45% fluoride (F-); (ii) 5.42% sodium fluoride (NaF) varnish (pH 5.0, 2.45% F); (iii) 2% chlorhexidine (CHX) gel (pH 7.0); (iv) placebo varnish (pH 5.0); or (v) no agent (untreated). Dentine specimens were then exposed to human saliva mixed with McBain saliva for 8 h. Thereafter, McBain saliva containing 0.2% sucrose was applied daily, for 5 d, onto dentine specimens to stimulate formation of microcosm biofilm. Although a high correlation was found between the results of both methods regarding integrated mineral loss, the results of the methods did not show good agreement in Bland-Altman plots, with significant biases in calculations of lesion depth. Fluoride varnishes were able to reduce dentine demineralization (P < 0.05), while CHX failed to do so. Fluorides are still the best option to reduce dentine demineralization. Micro-CT may be used to measure dentine mineral loss, but not the lesion depth, for which TMR is superior.},
}
@article {pmid31584030,
year = {2019},
author = {Yadav, S and Sachdev, V and Malik, M and Chopra, R},
title = {Effect of three different compositions of topical fluoride varnishes with and without prior oral prophylaxis on Streptococcus mutans count in biofilm samples of children aged 2-8 years: A randomized controlled trial.},
journal = {Journal of the Indian Society of Pedodontics and Preventive Dentistry},
volume = {37},
number = {3},
pages = {286-291},
doi = {10.4103/JISPPD.JISPPD_62_19},
pmid = {31584030},
issn = {1998-3905},
mesh = {Biofilms ; Cariostatic Agents ; Child ; Child, Preschool ; *Dental Caries ; *Dental Plaque ; Fluorides ; Fluorides, Topical ; Humans ; Streptococcus mutans ; },
abstract = {Background: Various strategies for controlling caries focus on disrupting the interaction between risk factors. Of these, fluoride varnish has been shown to reduce the colony-forming (CFU) units and water-insoluble extracellular polysaccharide amount. Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and xylitol-containing fluoride varnishes have recently gained importance as caries-protective fluoride varnishes.<br><br>Aim: This study aims to assess and compare the reduction in Streptococcus mutans count in biofilm samples after topical application of three different fluoride varnishes and to evaluate the effect of oral prophylaxis prior to fluoride varnish application.<br><br>Materials and Methods: Sixty healthy children with no active caries, in the age group of 2-8 years, were randomly divided into Group A = fluoride varnish containing CPP-ACP; Group B = fluoride varnish containing xylitol; and Group C = fluoride varnish with 0.9% difluorosilane; further, the groups were divided into two subgroups, namely A1, B1, and C1 with prior oral prophylaxis and A2, B2, and C2 without oral prophylaxis. Plaque samples were collected at baseline, 1st month, and 3rd month; cultured; and incubated, and CFU/ml was calculated.<br><br>Results: Data were compiled, and CFU/ml was analyzed by independent t-test, paired t-test, and one-way ANOVA. There was no statistical difference between the fluoride groups. Furthermore, no statistically significant difference was seen between the subgroups.<br><br>Conclusion: Fluoride varnish containing CPP-ACP showed higher reduction in S. mutans count followed by xylitol-containing fluoride varnish and Fluor Protector®. There was no effect of prior oral prophylaxis on the efficacy of fluoride varnish.},
}
@article {pmid31583791,
year = {2019},
author = {Dundas, AA and Sanni, O and Dubern, JF and Dimitrakis, G and Hook, AL and Irvine, DJ and Williams, P and Alexander, MR},
title = {Validating a Predictive Structure-Property Relationship by Discovery of Novel Polymers which Reduce Bacterial Biofilm Formation.},
journal = {Advanced materials (Deerfield Beach, Fla.)},
volume = {31},
number = {49},
pages = {e1903513},
doi = {10.1002/adma.201903513},
pmid = {31583791},
issn = {1521-4095},
support = {EP/N006615/1//Engineering and Physical Sciences Research Council/ ; 103882/WT_/Wellcome Trust/United Kingdom ; 103884/WT_/Wellcome Trust/United Kingdom ; //University of Nottingham/ ; },
abstract = {Synthetic materials are an everyday component of modern healthcare yet often fail routinely as a consequence of medical-device-centered infections. The incidence rate for catheter-associated urinary tract infections is between 3% and 7% for each day of use, which means that infection is inevitable when resident for sufficient time. The O'Neill Review on antimicrobial resistance estimates that, left unchecked, ten million people will die annually from drug-resistant infections by 2050. Development of biomaterials resistant to bacterial colonization can play an important role in reducing device-associated infections. However, rational design of new biomaterials is hindered by the lack of quantitative structure-activity relationships (QSARs). Here, the development of a predictive QSAR is reported for bacterial biofilm formation on a range of polymers, using calculated molecular descriptors of monomer units to discover and exemplify novel, biofilm-resistant (meth-)acrylate-based polymers. These predictions are validated successfully by the synthesis of new monomers which are polymerized to create coatings found to be resistant to biofilm formation by six different bacterial pathogens: Pseudomonas aeruginosa, Proteus mirabilis, Enterococcus faecalis, Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus.},
}
@article {pmid31583108,
year = {2019},
author = {Guilhen, C and Miquel, S and Charbonnel, N and Joseph, L and Carrier, G and Forestier, C and Balestrino, D},
title = {Colonization and immune modulation properties of Klebsiella pneumoniae biofilm-dispersed cells.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {25},
pmid = {31583108},
issn = {2055-5008},
abstract = {Biofilm-dispersal is a key determinant for further dissemination of biofilm-embedded bacteria. Recent evidence indicates that biofilm-dispersed bacteria have transcriptional features different from those of both biofilm and planktonic bacteria. In this study, the in vitro and in vivo phenotypic properties of Klebsiella pneumoniae cells spontaneously dispersed from biofilm were compared with those of planktonic and sessile cells. Biofilm-dispersed cells, whose growth rate was the same as that of exponential planktonic bacteria but significantly higher than those of sessile and stationary planktonic forms, colonized both abiotic and biotic surfaces more efficiently than their planktonic counterparts regardless of their initial adhesion capabilities. Microscopy studies suggested that dispersed bacteria initiate formation of microcolonies more rapidly than planktonic bacteria. In addition, dispersed cells have both a higher engulfment rate and better survival/multiplication inside macrophages than planktonic cells and sessile cells. In an in vivo murine pneumonia model, the bacterial load in mice lungs infected with biofilm-dispersed bacteria was similar at 6, 24 and 48 h after infection to that of mice lungs infected with planktonic or sessile bacteria. However, biofilm-dispersed and sessile bacteria trend to elicit innate immune response in lungs to a lesser extent than planktonic bacteria. Collectively, the findings from this study suggest that the greater ability of K. pneumoniae biofilm-dispersed cells to efficiently achieve surface colonization and to subvert the host immune response confers them substantial advantages in the first steps of the infection process over planktonic bacteria.},
}
@article {pmid31581486,
year = {2019},
author = {Aquino-Martins, VGQ and Melo, LFM and Silva, LMP and Targino de Lima, TR and Fernandes Queiroz, M and Viana, RLS and Zucolotto, SM and Andrade, VS and Rocha, HAO and Scortecci, KC},
title = {In Vitro Antioxidant, Anti-Biofilm, and Solar Protection Activities of Melocactus zehntneri (Britton &amp; Rose) Pulp Extract.},
journal = {Antioxidants (Basel, Switzerland)},
volume = {8},
number = {10},
pages = {},
pmid = {31581486},
issn = {2076-3921},
support = {111//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; scholarship//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; },
abstract = {Cactaceae plants are important due to their nutritional and therapeutic values. This study aimed to identify the phytochemical profile and biological activities of six Melocactus zehntneri pulp extracts: hexane extract (HE), chloroform extract (CE), ethanol extract (EE), methanol extract (ME), final water extract (FWE), and water extract (WE). Sugar, phenolic compounds, and protein content of the extracts were determined. Then thin layer chromatography (TLC) was performed to detect the presence of terpenes (ursolic and oleanolic acids), saponins, sugars, and glycoproteins. These extracts were analyzed for antioxidant activity via in vitro assay. HE showed 75% ferric chelating activity. All extracts showed 80-100% superoxide and hydroxyl radical-scavenging activities, respectively. Further, all extracts at 25 µg/mL showed 60% activity against DPPH. Moreover, in the 3T3 cells lines, no cytotoxicity was observed; however, therapeutic activity against the effects of the H2O2 treatment was exhibited. Finally, the polar extracts (EE, ME, FWE, and WE), particularly WE, elicited activity against the biofilms of Staphylococcus epidermidis, and HE and CE expressed a capacity for solar protection.},
}
@article {pmid31581038,
year = {2019},
author = {Henning, N and Falås, P and Castronovo, S and Jewell, KS and Bester, K and Ternes, TA and Wick, A},
title = {Biological transformation of fexofenadine and sitagliptin by carrier-attached biomass and suspended sludge from a hybrid moving bed biofilm reactor.},
journal = {Water research},
volume = {167},
number = {},
pages = {115034},
doi = {10.1016/j.watres.2019.115034},
pmid = {31581038},
issn = {1879-2448},
mesh = {*Biofilms ; Biomass ; Bioreactors ; Chromatography, Liquid ; *Sewage ; Sitagliptin Phosphate ; Tandem Mass Spectrometry ; Terfenadine/analogs &amp; derivatives ; },
abstract = {Laboratory-scale experiments were conducted to investigate the (bio)transformation of the antidiabetic sitagliptin (STG) and the antihistamine fexofenadine (FXF) during wastewater treatment. As inoculum either attached-growth on carriers or suspended sludge from a hybrid moving bed biofilm reactor (HMBBR) was used. Both target compounds were incubated in degradation experiments and quantified via LC-MS/MS for degradation kinetics. Furthermore transformation products (TPs) were analyzed via high resolution mass spectrometry (HRMS). Structural elucidation of the TPs was based on the high resolution molecular ion mass to propose a molecular formula and on MS2 fragmentation to elucidate the chemical structure of the TPs. In total, 22 TPs (9 TPs for STG and 13 TPs for FXF) were detected in the experiments with STG and FXF. For all TPs, chemical structures could be proposed. STG was mainly transformed via amide hydrolysis and conjugation of the primary amine moiety. In contrast, FXF was predominantly transformed by oxidative reactions such as oxidation (dehydrogenation) and hydroxylation. Furthermore, FXF was removed significantly faster in contact with carriers compared to suspended sludge, whereas STG was degraded slightly faster in contact with suspended sludge. Moreover, the primary TP of FXF was also degraded faster in contact with carriers leading to higher proportions of secondary TPs. Thus, the microbial community of both carriers and suspended sludge catalyzed the same primary transformation reactions but the transformation kinetics of FXF and the formation/degradation of FXF TPs were considerably higher in contact with carrier-attached biomass. The primary degradation of both target compounds in pilot- and full-scale conventional activated sludge (CAS) and MBBR reactors reached 42 and 61% for FXF and STG, respectively. Up to three of the identified TPs of FXF and 8 TPs of STG were detected in the effluents of pilot- and full-scale CAS and MBBR.},
}
@article {pmid31580958,
year = {2019},
author = {Arteaga, V and Lamas, A and Regal, P and Vázquez, B and Miranda, JM and Cepeda, A and Franco, CM},
title = {Antimicrobial activity of apitoxin from Apis mellifera in Salmonella enterica strains isolated from poultry and its effects on motility, biofilm formation and gene expression.},
journal = {Microbial pathogenesis},
volume = {137},
number = {},
pages = {103771},
doi = {10.1016/j.micpath.2019.103771},
pmid = {31580958},
issn = {1096-1208},
abstract = {Salmonella is a major global food-borne pathogen. One of the main concerns related to Salmonella and other food-borne pathogens is their capacity to acquire antimicrobial resistance and produce biofilms. Due to the increased resistance to common antimicrobials used to treat livestock animals and human infections, the discovery of new antimicrobial substances is one of the main challenges in microbiological research. An additional challenge is the development of new methods and substances to inhibit and destruct biofilms. We determined the antimicrobial and antibiofilm activities of apitoxin in 16 Salmonella strains isolated from poultry. In addition, the effect of apitoxin on Salmonella motility and the expression of biofilm- and virulence-related genes was evaluated. The minimum inhibitory concentrations (MIC) of apitoxin ranged from 1,024-256 μg/mL, with 512 μg/mL being the most common. Sub-inhibitory concentrations of apitoxin significantly reduced biofilm formation in 14 of the 16 Salmonella strains tested, with significant increases in motility. MIC concentrations of apitoxin destroyed the pre-formed biofilm by 27.66-68.22% (47.00% ± 10.91). The expression of biofilm- and virulence-related genes and small RNAs was differentially regulated according to the strain and the presence of apitoxin. The transcription of the small RNAs dsrA and csrB, related to antimicrobial resistance, was upregulated in the presence of apitoxin. We suggest that apitoxin is a potential antimicrobial substance that could be used in combination with other substances to develop new drugs and sanitizers against food-borne pathogens.},
}
@article {pmid31579334,
year = {2019},
author = {Kamiya, M and Mori, T and Nomura, M and Inagaki, T and Nonogaki, T and Nagatsu, A and Yamagishi, Y and Mikamo, H and Ikeda, Y},
title = {Tradescantia pallida extract inhibits biofilm formation in Pseudomonas aeruginosa.},
journal = {Nagoya journal of medical science},
volume = {81},
number = {3},
pages = {439-452},
pmid = {31579334},
issn = {2186-3326},
abstract = {Pseudomonas aeruginosa is capable of biofilm formation. In this study, we investigated the effects of aqueous Tradescantia pallida extract on Pseudomonas aeruginosa growth and biofilm formation. Aqueous Tradescantia pallida extracts significantly inhibited both bacterial growth and biofilm formation. However, methanolic Tradescantia pallida extracts inhibited neither. Aqueous Tradescantia pallida extracts were deactivated by heating but were not deactivated by light exposure. The ingredients retained the inhibitory effect on the bacterial growth and biofilm formation after ultrafiltration of aqueous Tradescantia pallida extract. Furthermore, polyphenol-rich Tradescantia pallida extracts inhibited bacterial growth, thus, polyphenols are possible to be an active ingredient. We observed the biofilm by scanning electron microscopy, and quantitative and qualitative differences in the biofilm and cells morphology. Interestingly, the biofilm treated aqueous Tradescantia pallida extracts remained premature. We postulated that premature biofilm formation was due to the inhibition of swarming motility. Indeed, aqueous Tradescantia pallida extracts inhibited swarming motility. These results demonstrate that Peudomonas aeruginosa growth and biofilm formation are inhibited by aqueous Tradescantia pallida extracts.},
}
@article {pmid31578154,
year = {2019},
author = {Shi, YJ and Fang, QJ and Huang, HQ and Gong, CG and Hu, YH},
title = {HutZ is required for biofilm formation and contributes to the pathogenicity of Edwardsiella piscicida.},
journal = {Veterinary research},
volume = {50},
number = {1},
pages = {76},
pmid = {31578154},
issn = {1297-9716},
support = {41476138//National Natural Science Foundation of China/ ; },
abstract = {Edwardsiella piscicida is a severe fish pathogen. Haem utilization systems play an important role in bacterial adversity adaptation and pathogenicity. In this study, a speculative haem utilization protein, HutZEp, was characterized in E. piscicida. hutZEp is encoded with two other genes, hutW and hutX, in an operon that is similar to the haem utilization operon hutWXZ identified in V. cholerae. However, protein activity analysis showed that HutZEp is probably not related to hemin utilization. To explore the biological role of HutZEp, a markerless hutZEp in-frame mutant strain, TX01ΔhutZ, was constructed. Deletion of hutZEp did not significantly affect bacterial growth in normal medium, in iron-deficient conditions, or in the presence of haem but significantly retarded bacterial biofilm growth. The expression of known genes related to biofilm growth was not affected by hutZEp deletion, which indicated that HutZEp was probably a novel factor promoting biofilm formation in E. piscicida. Compared to the wild-type TX01, TX01ΔhutZ exhibited markedly compromised tolerance to acid stress and host serum stress. Pathogenicity analysis showed that inactivation of hutZEp significantly impaired the ability of E. piscicida to invade and reproduce in host cells and to infect host tissue. In contrast to TX01, TX01ΔhutZ was defective in blocking host macrophage activation. The expression of hutZEp was directly regulated by the ferric uptake regulator Fur. This study is the first functional characterization of HutZ in a fish pathogen, and these findings suggested that HutZEp is essential for E. piscicida biofilm formation and contributes to host infection.},
}
@article {pmid31575315,
year = {2019},
author = {Namgoong, S and Jung, SY and Han, SK and Kim, AR and Dhong, ES},
title = {Clinical experience with surgical debridement and simultaneous meshed skin grafts in treating biofilm-associated infection: an exploratory retrospective pilot study.},
journal = {Journal of plastic surgery and hand surgery},
volume = {},
number = {},
pages = {1-8},
doi = {10.1080/2000656X.2019.1673170},
pmid = {31575315},
issn = {2000-6764},
abstract = {Current treatment guidelines for biofilm-associated infections (BAI) recommend repeated sharp/surgical debridement followed by treatment with antimicrobial agents until the wound becomes self-sustaining in terms of a positive wound-healing trajectory. However, complete removal of a biofilm is unlikely, and biofilms reform rapidly. We have treated BAI in patients with chronic diabetic ulcers using a meshed skin graft combined with negative pressure wound therapy (NPWT) immediately after surgical debridement, rather than waiting until the development of clean and healthy granulation tissue; the purpose of this exploratory study was to report the clinical results of this treatment strategy. This retrospective study included 75 patients with chronic diabetic ulcers who were treated for BAI by using surgical debridement, simultaneous meshed skin grafts, and NPWT. Healing time along with the percentage of complete wound closure within 12 weeks were evaluated; bacteria isolated from the wounds and their relation to the wound healing rate were investigated. All 75 wounds healed successfully, and the mean time for complete wound healing was 3.5 ± 1.8 weeks. In particular, 76% of wounds healed uneventfully without graft loss. A mean of 3.3 bacterial colonies/wound were isolated; however, no significant difference in wound healing was observed between the monomicrobial and polymicrobial groups. This exploratory study suggests that surgical debridement and simultaneous meshed skin grafts combined with NPWT may be successfully used to combat BAI in patients with chronic diabetic ulcers. We look forward to larger pivotal studies to confirm or refute these initially promising findings.},
}
@article {pmid31574542,
year = {2019},
author = {Meyer, F and Enax, J},
title = {Hydroxyapatite in Oral Biofilm Management.},
journal = {European journal of dentistry},
volume = {13},
number = {2},
pages = {287-290},
pmid = {31574542},
issn = {1305-7456},
abstract = {Particulate hydroxyapatite, Ca5 (PO4)3 (OH), shows a good biocompatibility and is used as a biomimetic ingredient in dental care formulations due to its similarity to human enamel. Numerous studies show its efficiency, for example, in reducing dentin hypersensitivity, and in the remineralization of enamel and dentin. In addition, oral care products with hydroxyapatite improve periodontal health under in vivo conditions. This review article summarizes data on the effects of hydroxyapatite particles in oral biofilm management. Two databases (PubMed and SciFinder) were searched for studies using specific search terms. In contrast to frequently used antibacterial agents for biofilm control, such as chlorhexidine, stannous salts, and quaternary ammonium salts, hydroxyapatite particles in oral care products lead to a reduction in bacterial attachment to enamel surfaces in situ without having pronounced antibacterial effects or showing unwanted side effects such as tooth discoloration. Furthermore, antibacterial agents might lead to dysbiosis of the oral ecology, which was recently discussed regarding pros and cons. Remarkably, the antiadherent properties of hydroxyapatite particles are comparable to those of the gold standard in the field of oral care biofilm management, chlorhexidine in situ. Although biomimetic strategies have been less well analyzed compared with commonly used antibacterial agents in oral biofilm control, hydroxyapatite particles are a promising biomimetic alternative or supplement for oral biofilm management.},
}
@article {pmid31574321,
year = {2019},
author = {Fugolin, AP and Dobson, A and Huynh, V and Mbiya, W and Navarro, O and Franca, CM and Logan, M and Merritt, JL and Ferracane, JL and Pfeifer, CS},
title = {Antibacterial, ester-free monomers: Polymerization kinetics, mechanical properties, biocompatibility and anti-biofilm activity.},
journal = {Acta biomaterialia},
volume = {100},
number = {},
pages = {132-141},
pmid = {31574321},
issn = {1878-7568},
support = {K02 DE025280/DE/NIDCR NIH HHS/United States ; R01 DE026113/DE/NIDCR NIH HHS/United States ; R01 DE028757/DE/NIDCR NIH HHS/United States ; U01 DE023756/DE/NIDCR NIH HHS/United States ; },
abstract = {OBJECTIVES: Quaternary ammonium (QA) methacrylate monomers have been extensively investigated and demonstrate excellent antibacterial properties. However, the presence of ester bonds makes them prone to degradation in the oral cavity. In this study, ester-free QA monomers based on meth-acrylamides were synthesized and screened for polymerization kinetics, mechanical properties and antibacterial effects.<br><br>MATERIALS AND METHODS: Tertiary quaternary ammonium acrylamides (AM) and methacrylamides (MAM) with alkyl side chain lengths of 9 and 14 carbons (C9 and C14) were synthesized and incorporated at 10 wt% into experimental composites based on BisGMA:TEGDMA (1:1), camphorquinone/ethyl-4-dimethylaminobenzoate (0.2/0.8 wt%) and 70 wt% barium glass fillers. Analogous methacrylate versions (MA) were used as controls. Degree of conversion (DC) and rate of polymerization (RP) during photoactivation (800 mW/cm2) were followed in real-time with near-IR. Flexural Strength (FS) and Modulus (E) were measured on 2 × 2 × 25 mm bars in 3-point bending after 24 h dry storage and 7-day storage in water at 37 °C. Antimicrobial properties and biofilm adhesion (fouling) were evaluated by bioluminescence (Luciferase Assay) and biofilm removal by water spray microjet impingement test, respectively. Cytotoxicity was assessed by MTT assay on dental pulp stem cells (DPSC). Data were analyzed with one-way ANOVA/Tukey's test (α = 0.05).<br><br>RESULTS: DC was similar for all groups tested (∼70%). Both MAMs and C14-AM presented significantly lower RP. Under dry conditions, FS (110-120 MPa) and E (8-9 GPa) were similar for all groups. After water storage, all materials presented FS/E similar to the control, except for C14-AM (for FS) and C14-MAM (for E), which were lower. All C14 versions were strongly antibacterial, decreasing the titer counts of biofilm by more than two orders of magnitude in comparison to the control. C9 monomers did not present significant antibacterial nor antifouling properties. And biofilms had approximately equivalent adhesion on the C9 composites as on the control. Cytotoxicity did not show significant differences between the MA and AM versions and the control group.<br><br>CONCLUSIONS: C14-QA monomers based on methacrylates and meth-acrylamides present strong antibacterial properties, and in general, similar conversion/mechanical properties compared to the methacrylate control.<br><br>STATEMENT OF SIGNIFICANCE: This work demonstrates the viability of methacrylamides and acrylamides as potential components in dental restorative materials with antimicrobial properties. The use of ester-free polymerizable functionalities has the potential of improving the degradation resistance of these materials long-term. The use of (meth)acrylamides did not interfere with the antimicrobial potential of quaternary ammonium-based materials.},
}
@article {pmid31573125,
year = {2019},
author = {Romeu, MJ and Alves, P and Morais, J and Miranda, JM and de Jong, ED and Sjollema, J and Ramos, V and Vasconcelos, V and Mergulhão, FJM},
title = {Biofilm formation behaviour of marine filamentous cyanobacterial strains in controlled hydrodynamic conditions.},
journal = {Environmental microbiology},
volume = {21},
number = {11},
pages = {4411-4424},
doi = {10.1111/1462-2920.14807},
pmid = {31573125},
issn = {1462-2920},
support = {SFRH/BD/140080/2018//FCT/ ; CA15216//ENBA/ ; TD1305//iPROMEDAI/ ; 0302_CVMAR_I_1_P//INTERREG V A Espanha Portugal (POCTEP)/ ; UID/EQU/00511/2019//FCT/MCTES (PIDDAC)/ ; },
abstract = {Marine biofouling has severe economic impacts and cyanobacteria play a significant role as early surface colonizers. Despite this fact, cyanobacterial biofilm formation studies in controlled hydrodynamic conditions are scarce. In this work, computational fluid dynamics was used to determine the shear rate field on coupons that were placed inside the wells of agitated 12-well microtiter plates. Biofilm formation by three different cyanobacterial strains was assessed at two different shear rates (4 and 40 s-1) which can be found in natural ecosystems and using different surfaces (glass and perspex). Biofilm formation was higher under low shear conditions, and differences obtained between surfaces were not always statistically significant. The hydrodynamic effect was more noticeable during the biofilm maturation phase rather than during initial cell adhesion and optical coherence tomography showed that different shear rates can affect biofilm architecture. This study is particularly relevant given the cosmopolitan distribution of these cyanobacterial strains and the biofouling potential of these organisms.},
}
@article {pmid31570700,
year = {2019},
author = {Jiao, Y and Tay, FR and Niu, LN and Chen, JH},
title = {Advancing antimicrobial strategies for managing oral biofilm infections.},
journal = {International journal of oral science},
volume = {11},
number = {3},
pages = {28},
pmid = {31570700},
issn = {2049-3169},
mesh = {Anti-Bacterial Agents/*pharmacology/therapeutic use ; Anti-Infective Agents/pharmacology/therapeutic use ; Bacterial Infections/*drug therapy ; Biofilms/*drug effects ; Humans ; Mouth/*microbiology ; Plankton ; },
abstract = {Effective control of oral biofilm infectious diseases represents a major global challenge. Microorganisms in biofilms exhibit increased drug tolerance compared with planktonic cells. The present review covers innovative antimicrobial strategies for controlling oral biofilm-related infections published predominantly over the past 5 years. Antimicrobial dental materials based on antimicrobial agent release, contact-killing and multi-functional strategies have been designed and synthesized for the prevention of initial bacterial attachment and subsequent biofilm formation on the tooth and material surface. Among the therapeutic approaches for managing biofilms in clinical practice, antimicrobial photodynamic therapy has emerged as an alternative to antimicrobial regimes and mechanical removal of biofilms, and cold atmospheric plasma shows significant advantages over conventional antimicrobial approaches. Nevertheless, more preclinical studies and appropriately designed and well-structured multi-center clinical trials are critically needed to obtain reliable comparative data. The acquired information will be helpful in identifying the most effective antibacterial solutions and the most optimal circumstances to utilize these strategies.},
}
@article {pmid31570396,
year = {2019},
author = {Lopes, AA and Yoshii, Y and Yamada, S and Nagakura, M and Kinjo, Y and Mizunoe, Y and Okuda, KI},
title = {Roles of lytic transglycosylases in biofilm formation and β-lactam resistance in methicillin-resistant Staphylococcus aureus.},
journal = {Antimicrobial agents and chemotherapy},
volume = {},
number = {},
pages = {},
pmid = {31570396},
issn = {1098-6596},
abstract = {Staphylococcus aureus is responsible for numerous community outbreaks and is one of the most frequent causes of nosocomial infections with significant morbidity and mortality. While the function of lytic transglycosylases (LTs) in relation to cell division, biofilm formation, and antibiotic resistance has been determined for several bacteria, their role in S. aureus remains largely unknown. The only known LTs in S. aureus are immunodominant staphylococcal antigen A (IsaA) and Staphylococcus epidermidis D protein (SceD). Our study demonstrates that, in a strain of methicillin-resistant S. aureus (MRSA), IsaA and SceD contribute differently to biofilm formation and β-lactam resistance. Deletion of isaA, but not sceD, led to decreased biofilm formation. Additionally, in isaA-deleted strains, β-lactam resistance was significantly decreased compared to that of wild-type strains. Plasmid-based expression of mecA, a major determinant of β-lactam resistance in MRSA, in an isaA-deleted strain did not restore β-lactam resistance, demonstrating that the β-lactam susceptibility phenotype is exhibited by isaA mutant regardless of the production level of PBP2a. Overall, our results suggest that IsaA is a potential therapeutic target for MRSA infections.},
}
@article {pmid31565797,
year = {2019},
author = {Wang, X and Kong, Y and Zhao, H and Yan, X},
title = {Dependence of the Bacillus subtilis biofilm expansion rate on phenotypes and the morphology under different growing conditions.},
journal = {Development, growth &amp; differentiation},
volume = {61},
number = {7-8},
pages = {431-443},
doi = {10.1111/dgd.12627},
pmid = {31565797},
issn = {1440-169X},
support = {//Harvard University/ ; 11772047//The National Natural Science Foundation of China/ ; 11620101001//The National Natural Science Foundation of China/ ; 2017YFB1002701//National Key R&amp;D Program of China/ ; },
abstract = {Biofilms are communities of tightly associated bacteria encased in an extracellular matrix and attached to surfaces of various objects, such as liquid or solid surfaces. Here we use the multi-channel wide field stereo fluorescence microscope to characterize growth of the Bacillus subtilis biofilm, in which the bacterial strain was triple fluorescence labeled for three main phenotypes: motile, matrix producing and sporulating cells. We used the feature point matching approach analyzing time lapse experimental movies to study the biofilm expansion rate. We found that the matrix producing cells dominate the biofilm expansion, at the biofilm edge, the expansion rate of matrix producing cells was almost the same as the velocity of the whole biofilm; however, the motile and sporulating cells were nearly rest. We also found that the biofilm expansion rate evolution relates to cell differentiation and biofilm morphology, and other micro-environments can influence the biofilm growth, such as nutrient, substrate hardness and colony competition. From our work, we get a deeper understanding of the biofilm growth, which can help us to control and to further disperse the biofilm.},
}
@article {pmid31563809,
year = {2019},
author = {Han, C and Goodwine, J and Romero, N and Steck, KS and Sauer, K and Doiron, A},
title = {Enzyme-encapsulating polymeric nanoparticles: A potential adjunctive therapy in Pseudomonas aeruginosa biofilm-associated infection treatment.},
journal = {Colloids and surfaces. B, Biointerfaces},
volume = {184},
number = {},
pages = {110512},
pmid = {31563809},
issn = {1873-4367},
support = {R56 AI127815/AI/NIAID NIH HHS/United States ; },
abstract = {Pseudomonas aeruginosa is a pathogen known to be associated with a variety of diseases and conditions such as cystic fibrosis, chronic wound infections, and burn wound infections. A novel approach was developed to combat the problem of biofilm antibiotic tolerance by reverting biofilm bacteria back to the planktonic mode of growth. This reversion was achieved through the enzymatic depletion of available pyruvate using pyruvate dehydrogenase, which induced biofilm bacteria to disperse from the surface-associated mode of growth into the surrounding environment. However, direct use of the enzyme in clinical settings is not practical as the enzyme is susceptible to denaturation under various storage conditions. We hypothesize that by encapsulating pyruvate dehydrogenase into degradable, biocompatible poly(lactic-co-glycolic) acid nanoparticles, the activity of the enzyme can be extended to deplete available pyruvate and induce dispersion of mature Pseudomonas aeruginosa biofilms. Several particle formulations were attempted in order to permit the use of the smallest dose of nanoparticles while maintaining pyruvate dehydrogenase activity for an extended time length. The nanoparticles synthesized using the optimal formulation showed an average size of 266.7 ± 1.8 nm. The encapsulation efficiency of pyruvate dehydrogenase was measured at 17.9 ± 1.4%. Most importantly, the optimal formulation dispersed biofilms and exhibited enzymatic activity after being stored at 37 °C for 6 days.},
}
@article {pmid31563763,
year = {2020},
author = {Kart, D and Yabanoglu Ciftci, S and Nemutlu, E},
title = {Altered metabolomic profile of dual-species biofilm: Interactions between Proteus mirabilis and Candida albicans.},
journal = {Microbiological research},
volume = {230},
number = {},
pages = {126346},
doi = {10.1016/j.micres.2019.126346},
pmid = {31563763},
issn = {1618-0623},
abstract = {In this study, we aimed to determine the interspecies interactions between Proteus mirabilis and Candida albicans. Mono and dual-species biofilms were grown in a microtiter plate and metabolomic analysis of the biofilms was performed. The effects of togetherness of two species on the expression levels of candidal virulence genes and urease and swarming activities of P.mirabilis were investigated. The growth of C.albicans was inhibited by P.mirabilis whereas the growth and swarming activity of P.mirabilis were increased by C.albicans. The inhibition of Candida cell growth was found to be biofilm specific. The alteration was not detected in urease activity. The expressions of EFG1, HWP1 and SAP2 genes were significantly down-regulated, however, LIP1 was upregulated by P.mirabilis. In the presence of P.mirabilis carbonhydrates, amino acids, polyamine and lipid metabolisms were altered in C.albicans. Interestingly, the putrescine level was increased up to 230 fold in dual-species biofilm compared to monospecies C.albicans biofilm. To our knowledge, this is the first study to investigate the impact of each microbial pathogen on the dual microbial environment by integration of metabolomic data.},
}
@article {pmid31562986,
year = {2019},
author = {Caizán-Juanarena, L and Krug, JR and Vergeldt, FJ and Kleijn, JM and Velders, AH and Van As, H and Ter Heijne, A},
title = {3D biofilm visualization and quantification on granular bioanodes with magnetic resonance imaging.},
journal = {Water research},
volume = {167},
number = {},
pages = {115059},
doi = {10.1016/j.watres.2019.115059},
pmid = {31562986},
issn = {1879-2448},
mesh = {*Bioelectric Energy Sources ; Biofilms ; Electricity ; Electrodes ; Magnetic Resonance Imaging ; },
abstract = {The use of microbial fuel cells (MFCs) for wastewater treatment fits in a circular economy context, as they can produce electricity by the removal of organic matter in the wastewater. Activated carbon (AC) granules are an attractive electrode material for bioanodes in MFCs, as they are cheap and provide electroactive bacteria with a large surface area for attachment. The characterization of biofilm growth on AC granules, however, is challenging due to their high roughness and three-dimensional structure. In this research, we show that 3D magnetic resonance imaging (MRI) can be used to visualize biofilm distribution and determine its volume on irregular-shaped single AC granules in a non-destructive way, while being combined with electrochemical and biomass analyses. Ten AC granules with electroactive biofilm (i.e. granular bioanodes) were collected at different growth stages (3 to 21 days after microbial inoculation) from a multi-anode MFC and T1-weighted 3D-MRI experiments were performed for three-dimensional biofilm visualization. With time, a more homogeneous biofilm distribution and an increased biofilm thickness could be observed in the 3D-MRI images. Biofilm volumes varied from 0.4 μL (day 4) to 2 μL (day 21) and were linearly correlated (R2 = 0.9) to the total produced electric charge and total nitrogen content of the granular bioanodes, with values of 66.4 C μL-1 and 17 μg N μL-1, respectively. In future, in situ MRI measurements could be used to monitor biofilm growth and distribution on AC granules.},
}
@article {pmid31561688,
year = {2019},
author = {Jain, AK and Misra, V and Ranjan, N and Jain, SB and Gandhi, S},
title = {Speciation, Biofilm Formation and Antifungal Susceptibility of Candida Isolates from Clinically Diagnosed Patient of UTI in a Tertiary Care Hospital.},
journal = {The Journal of the Association of Physicians of India},
volume = {67},
number = {9},
pages = {42-45},
pmid = {31561688},
issn = {0004-5772},
mesh = {Antifungal Agents/pharmacology/*therapeutic use ; Biofilms/*growth &amp; development ; Candida/*drug effects/isolation &amp; purification ; Humans ; Microbial Sensitivity Tests ; Tertiary Care Centers ; Urinary Tract Infections/*drug therapy/microbiology ; },
abstract = {Introduction: The incidence of the urinary tract infections caused by Candida species, are becoming more common. Recently, an increase in the incidence of infection caused by fungi especially non albicans candida species (NAC) has been reported. Several virulence factors like biofilm formation, toxin production and presence of adhesins contribute to its pathogenesis.<br><br>Objectives: This study was undertaken to determine species distribution, biofilm formation and in-vitro antifungal susceptibility of candida isolated in our tertiary care hospital.<br><br>Method: Eighty seven clinical isolates obtained from urine specimens were subjected to wet mount, Gram's stain and cultured on Sabouraud's Dextrose agar (SDA) medium. Conventional method for yeast identification was done. Biofilm forming ability of each isolate was detected using microtitre plate method. Antifungal susceptibility against posaconazole, amphotericin-B, fluconazole, itraconazole, ketoconazole, 5-flucytosine, voriconazole, and caspofungin was tested using Sensititre® Yeastone® (Trek diagnostic systems).<br><br>Results and Discussion: Out of 87 candida isolates, 31.03% (n=27) were C. albicans and 68.97% (n=60) were non albicans candida species (NAC). Among 60 NAC, C. kruseii 29.89% (n=26), C. glabrata 24.14% (n=21), C. tropicalis 14.94% (n=13). Among all isolates, 36.78% (n=32) were biofilm producers and biofilm positivity more among C. albicans 55.56% (n=15) as compared to NAC 28.33% (n=17) (Pvalue<0.002). The maximum positivity was observed with isolates from plastic devices (61.8%). The minimum inhibitory concentrations of all antifungal drugs against all isolates were within susceptible range except for fluconazole which was resistant to C. kruseii.<br><br>Conclusion: C. albicans remains the major isolate from urine samples and also biofilm formation as a virulence factor might have a higher significance for C. albicans than for NAC and its ability to form biofilm is intricately linked with ability of organisms to adhere, colonize and subsequently cause infection.},
}
@article {pmid31561306,
year = {2019},
author = {Yu, Z and Li, W and Tan, S},
title = {Real-time monitoring of the membrane biofouling based on spectroscopic analysis in a marine MBBR-MBR (moving bed biofilm reactor-membrane bioreactor) for saline wastewater treatment.},
journal = {Chemosphere},
volume = {235},
number = {},
pages = {1154-1161},
doi = {10.1016/j.chemosphere.2019.07.005},
pmid = {31561306},
issn = {1879-1298},
mesh = {Biodegradation, Environmental ; *Biofilms ; Biofouling/*prevention &amp; control ; *Bioreactors ; *Membranes, Artificial ; Salinity ; Spectrum Analysis ; Waste Water/*chemistry ; Water Purification/methods ; },
abstract = {A MBBR-MBR system has been developed with marine microorganisms enriched for saline wastewater treatment in this work, showing high COD and NH3-N removals. The behaviour of fouling-related components (EPS and SMP) has been studied as functions of operating time (40-90 days), salinity (0-30 g/L NaCl) and backflow ratio (0-300%, from MBR to MBBR). High biodegradability of the MBBR-MBR at optimal conditions can induce more biodegradation of humic acid-like (λex/λem: 350nm/430 nm) and fulvic acid-like (260nm/445 nm) molecules to soluble microbial by-product-like molecules (275nm/325 nm), reducing the membrane biofouling rate. The biodegradation process is suggested by the excitation-emission matrix (EEM) images. In the study of sudden salinity shock, results show that real-time monitoring the concentration of biofoulants is more effective (operative time extended by 60%) than monitoring the transmembrane pressure (operative time extended by 33%) to prevent membrane fouling. Due to an early warning from the real-time monitoring, the coming membrane-fouling is predictable and the operating conditions, such as backflow ratio, can be changed to minimize the biofouling rate.},
}
@article {pmid31558046,
year = {2019},
author = {Oliveira, GS and Lopes, DRG and Andre, C and Silva, CC and Baglinière, F and Vanetti, MCD},
title = {Multispecies biofilm formation by the contaminating microbiota in raw milk.},
journal = {Biofouling},
volume = {35},
number = {8},
pages = {819-831},
doi = {10.1080/08927014.2019.1666267},
pmid = {31558046},
issn = {1029-2454},
abstract = {Biofilms can be formed on the surfaces of dairy processing equipment and are a potential source of product contamination. This study evaluated the diversity of multispecies biofilms formed on stainless steel (SS) due to the contaminating microbiota in raw milk. Samples of raw milk were used: one was fresh milk and the other maintained in refrigerated bulk tanks for up to 48 h. The mesophilic aerobic contamination was ∼104 CFU ml-1 in fresh milk and 106 CFU ml-1 in bulk milk. SS coupons were kept immersed in the milk at 7 ±2 °C for 10 days, and every two days, the raw milk was changed for samples of the same origin collected on the current day. After incubation for 10 days, sessile cells in the biofilm reached 105 CFU cm-2 in the presence of fresh milk, and 106 CFU cm-2 in the presence of bulk milk. The genetic diversity analysis showed that Gammaproteobacteria and Bacilli predominated in the biofilms throughout the incubation of both milk samples and these biofilms showed a reduction in diversity over time. The main classes of bacteria found in these biofilms have representatives of great importance since many of them have spoilage potential.},
}
@article {pmid31557551,
year = {2019},
author = {Kurt, A and Cilingir, A and Bilmenoglu, C and Topcuoglu, N and Kulekci, G},
title = {Effect of different polishing techniques for composite resin materials on surface properties and bacterial biofilm formation.},
journal = {Journal of dentistry},
volume = {90},
number = {},
pages = {103199},
doi = {10.1016/j.jdent.2019.103199},
pmid = {31557551},
issn = {1879-176X},
abstract = {OBJECTIVES: Both direct and indirect techniques are used for composite resin material (CRM) restorations. Polishing processes are needed in both techniques after intraoral adjustment. However, it is unclear as to which polishing technique should be preferred with respect to decreasing biofilm. The purpose of thisin vitro study was to evaluate the surface properties and Streptococcus mutans biofilm formation on direct and indirect CRMs after using different polishing techniques.<br><br>METHODS: Two CRMs (direct and indirect) and four polishing techniques (aluminium oxide discs, diamond polishing paste, aluminium oxide polishing paste, and silicon carbide brush) were evaluated. The specimens were prepared for taking scanning electron microscopy images (n = 2) and determining surface roughness, surface free energy, and bacterial biofilm formation (BBF) with colony-forming unit counting and confocal laser scanning microscopy assays (n = 7). The data were analysed using two-way analysis of variance with Bonferroni as a post hoc test and Pearson's correlation (p < .05).<br><br>RESULTS: The surface roughness values in the control group were higher than those in the diamond polishing paste group (p = 0.025), but the values in the aluminium oxide polishing paste and silicon carbide brush groups were comparable with those in the control group (p = 0.156 and p = 1.000, respectively). The highest surface free energy values were recorded in the silicon carbide brush group (p < 0.001), whereas there were no differences found among the other groups (p > 0.05). The highest BBF was seen in the silicon carbide brush (p < 0.001) and direct CRM (p < 0.001) groups.<br><br>CONCLUSION: BBF on the surface of direct CRMs differed from that on indirect CRMs after polishing the surface. The tested polishing techniques significantly influenced surface properties and BBF.<br><br>CLINICAL SIGNIFICANCE: In situations that require the intraoral adjustment of CRMs, polishing with a diamond polishing paste seems to be a good option to polish the surface of both direct and indirect CRMs because the diamond polishing paste results better in terms of decreasing biofilm formation and improving surface properties.},
}
@article {pmid31556843,
year = {2019},
author = {Horváthová, T and Bauchinger, U},
title = {Biofilm Improves Isopod Growth Independent of the Dietary Cellulose Content.},
journal = {Physiological and biochemical zoology : PBZ},
volume = {92},
number = {6},
pages = {531-543},
doi = {10.1086/705441},
pmid = {31556843},
issn = {1537-5293},
abstract = {Cellulose is an abundant source of carbon, accounting for more than 50% of foliage and 90% of woody tissues of plants. Despite the diversity of species that include living or dead plant tissue in their diets, the ability to digest cellulose through self-produced enzymatic machinery is considered rare in the animal kingdom. The majority of animals studied to date rely on the cellulolytic activity of symbiotic microorganisms in their digestive tract, with some evidence for a complementary action of endogenous cellulases. Terrestrial isopods have evolved a lifestyle including feeding on a lignocellulose diet. Whether isopods utilize both external and internal cellulases for digestion of a diet is still not understood. We experimentally manipulated the content of cellulose (30%, 60%, or 90%) and the amount of biofilm (small or large) in the offered food source and quantified growth and cellulolytic activity in the gut of the isopod Porcellio scaber. The presence of a visible biofilm significantly promoted isopod growth, regardless of the cellulose content in the diet. The activity of gut cellulases was not significantly affected by the amount of biofilm or the cellulose content. Our results do not support a significant contribution of either ingested or host enzymes to cellulose utilization in P. scaber. Cellulose might not represent a key nutrient for isopods and does not seem to affect the nutritional value of the diet-associated biofilm. We propose that it is the biofilm community that determines the quality of plant diet in terrestrial isopods and potentially also in other detrital plant feeders.},
}
@article {pmid31555777,
year = {2019},
author = {Lee, JK and Mereuta, L and Luchian, T and Park, Y},
title = {Antimicrobial peptide HPA3NT3-A2 effectively inhibits biofilm formation in mice infected with drug-resistant bacteria.},
journal = {Biomaterials science},
volume = {7},
number = {12},
pages = {5068-5083},
doi = {10.1039/c9bm01051c},
pmid = {31555777},
issn = {2047-4849},
abstract = {Bacterial biofilms formed through secretion of extracellular polymeric substances (EPS) have been implicated in many serious infections and can increase antibiotic resistance by a factor of more than 1000. Here, we examined the abilities of the antimicrobial peptide HPA3NT3-A2 to inhibit and reduce biofilm formation, eliminate EPS, and suppress inflammation in mice infected with clinical isolates of drug-resistant Pseudomonas aeruginosa strains. HPA3NT3-A2 was developed from a desirable analogue peptide, HPA3NT3, derived from residues 2-20 of the Helicobacter pylori ribosomal protein L1. HPA3NT3-A2 showed stronger activity against planktonic cells (MIC: 8 μM) compared to ciprofloxacin or tobramycin (>512 μM), and a favorable minimum biofilm inhibition and elimination concentration. This peptide also neutralized LPS; decreased levels of EPS; inhibited the production of pro-inflammatory cytokines in the lung, kidney, and spleen; decreased white blood cell counts; and increased survival among infected mice.},
}
@article {pmid31553873,
year = {2019},
author = {Sommer, R and Rox, K and Wagner, S and Hauck, D and Henrikus, SS and Newsad, S and Arnold, T and Ryckmans, T and Brönstrup, M and Imberty, A and Varrot, A and Hartmann, RW and Titz, A},
title = {Anti-biofilm Agents against Pseudomonas aeruginosa: A Structure-Activity Relationship Study of C-Glycosidic LecB Inhibitors.},
journal = {Journal of medicinal chemistry},
volume = {62},
number = {20},
pages = {9201-9216},
pmid = {31553873},
issn = {1520-4804},
abstract = {Biofilm formation is a key mechanism of antimicrobial resistance. We have recently reported two classes of orally bioavailable C-glycosidic inhibitors of the Pseudomonas aeruginosa lectin LecB with antibiofilm activity. They proved efficient in target binding, were metabolically stable, nontoxic, selective, and potent in inhibiting formation of bacterial biofilm. Here, we designed and synthesized six new carboxamides and 24 new sulfonamides for a detailed structure-activity relationship for two clinically representative LecB variants. Sulfonamides generally showed higher inhibition compared to carboxamides, which was rationalized based on crystal structure analyses. Substitutions at the thiophenesulfonamide increased binding through extensive contacts with a lipophilic protein patch. These metabolically stable compounds showed a further increase in potency toward the target and in biofilm inhibition assays. In general, we established the structure-activity relationship for these promising antibiofilm agents and showed that modification of the sulfonamide residue bears future optimization potential.},
}
@article {pmid31552285,
year = {2019},
author = {Kaldhone, PR and Carlton, A and Aljahdali, N and Khajanchi, BK and Sanad, YM and Han, J and Deck, J and Ricke, SC and Foley, SL},
title = {Evaluation of Incompatibility Group I1 (IncI1) Plasmid-Containing Salmonella enterica and Assessment of the Plasmids in Bacteriocin Production and Biofilm Development.},
journal = {Frontiers in veterinary science},
volume = {6},
number = {},
pages = {298},
doi = {10.3389/fvets.2019.00298},
pmid = {31552285},
issn = {2297-1769},
abstract = {Mobile genetic elements, such as plasmids, can potentially increase the ability of bacteria to infect and persist in vertebrate host cells. IncI1 plasmids are widely distributed in Salmonella from food animal sources and associated with clinically important strains. These plasmids often encode antimicrobial resistance; however, little is known about their impact on the virulence of Salmonella strains. To assess the potential impact of the plasmids on virulence, 43 IncI1-positive Salmonella isolates from human and animal sources were subjected to whole genome sequence (WGS) analyses and evaluated for their abilities to invade and persist for 48 h in Caco-2 human intestinal epithelial cells, form biofilms and encode bacteriocins. Draft WGS data were submitted to predict the presence of virulence and antimicrobial resistance genes, plasmid replicon types present, conduct plasmid multilocus sequence typing (pMLST), and core genome MLST (cgMLST) in the isolates. Caco-2 cells were infected with Salmonella strains and incubated for both one and 48 h for the invasion and persistence assays, respectively. Additionally, Salmonella isolates and IncI1 plasmid carrying transconjugants (n = 12) generated in Escherichia coli were assessed for their ability to produce biofilms and bacteriocin inhibition of growth of other bacteria. All Salmonella isolates infected Caco-2 cells and persisted in the cells at 48 hrs. Persistent cell counts were observed to be significantly higher than invasion assay cell counts in 26% of the isolates. Among the IncI1 plasmids, there were 18 pMLST types. Nearly 35% (n = 15) of Salmonella isolates produced biofilms; however, none of the IncI1-positive transconjugants produced increased biofilms compared to the recipient. Approximately 65% (n = 28) of isolates and 67% (n = 8) of IncI1-positive transconjugants were able to inhibit growth of at least one E. coli strain; however, none inhibited the growth of strains from species other than E. coli. The study characterized IncI1 positive Salmonella isolates and provided evidence about the potential contributions of IncI1 plasmids virulence phenotypes and areas where they do not. These findings should allow for more focused efforts to assess the impact of plasmids on bacterial pathophysiology and human health.},
}
@article {pmid31552139,
year = {2019},
author = {Willett, JLE and Ji, MM and Dunny, GM},
title = {Exploiting biofilm phenotypes for functional characterization of hypothetical genes in Enterococcus faecalis.},
journal = {NPJ biofilms and microbiomes},
volume = {5},
number = {},
pages = {23},
doi = {10.1038/s41522-019-0099-0},
pmid = {31552139},
issn = {2055-5008},
support = {R01 AI122742/AI/NIAID NIH HHS/United States ; R35 GM118079/GM/NIGMS NIH HHS/United States ; T32 HL007741/HL/NHLBI NIH HHS/United States ; },
abstract = {Enterococcus faecalis is a commensal organism as well as an important nosocomial pathogen, and its infections are typically linked to biofilm formation. Nearly 25% of the E. faecalis OG1RF genome encodes hypothetical genes or genes of unknown function. Elucidating their function and how these gene products influence biofilm formation is critical for understanding E. faecalis biology. To identify uncharacterized early biofilm determinants, we performed a genetic screen using an arrayed transposon (Tn) library containing ~2000 mutants in hypothetical genes/intergenic regions and identified eight uncharacterized predicted protein-coding genes required for biofilm formation. We demonstrate that OG1RF_10435 encodes a phosphatase that modulates global protein expression and arginine catabolism and propose renaming this gene bph (biofilm phosphatase). We present a workflow for combining phenotype-driven experimental and computational evaluation of hypothetical gene products in E. faecalis, which can be used to study hypothetical genes required for biofilm formation and other phenotypes of diverse bacteria.},
}
@article {pmid31552130,
year = {2019},
author = {El-Ezmerli, NF and Gregory, RL},
title = {Effect of nicotine on biofilm formation of Streptococcus mutans isolates from smoking and non-smoking subjects.},
journal = {Journal of oral microbiology},
volume = {11},
number = {1},
pages = {1662275},
doi = {10.1080/20002297.2019.1662275},
pmid = {31552130},
issn = {2000-2297},
abstract = {Objectives: To investigate effects of nicotine on biofilm formation of Streptococcus mutans isolates from oral washes of smoker and non-smoker human subjects. Materials and methods: This study was conducted using 60 S. mutans isolates with three S. mutans isolates collected from oral washes of ten smoking subjects and ten from non-smoking subjects. Biofilm was formed by culturing each S. mutans strain (10 μl) in 190 μl of TSB supplemented with 1% sucrose (TSBS) containing 0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0, and 32.0 mg/ml of nicotine for 24 h in 5% CO2 at 37°C in 96 well microtiter plates. The absorbance values of biofilm were measured at 490 nm in a microplate spectrophotometer. Results: There was a significant effect (p-value < 0.05) of nicotine concentrations and smoking on the growth of biofilm, planktonic cells, and total absorbance, for all strains of S. mutans. Isolates from smokers had significantly more biofilm at 0-16 mg/ml of nicotine compared to those from non-smokers (p-value < 0.0001). Conclusion: S. mutans smoker isolates are more affected by high nicotine concentrations than non-smoker isolates. Clinical Relevance: The use of nicotine products increases the growth of S. mutans and may place tobacco users at risk for dental decay.},
}
@article {pmid31551964,
year = {2019},
author = {Selvaraj, A and Jayasree, T and Valliammai, A and Pandian, SK},
title = {Myrtenol Attenuates MRSA Biofilm and Virulence by Suppressing sarA Expression Dynamism.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2027},
doi = {10.3389/fmicb.2019.02027},
pmid = {31551964},
issn = {1664-302X},
abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a deleterious human pathogen responsible for severe morbidity and mortality worldwide. The pathogen has attained high priority in the World Health Organization (WHO) - Multidrug-resistant (MDR) pathogens list. Emerging MDR strains of S. aureus are clinically challenging due to failure in conventional antibiotic therapy. Biofilm formation is one of the underlying mechanisms behind the antibiotic resistance. Hence, attenuating biofilm formation has become an alternative strategy to control persistent infections. The current study is probably the first that focuses on the antibiofilm and antivirulence potential of myrtenol against MRSA and its clinical isolates. Myrtenol exhibited a concentration-dependent biofilm inhibition without causing any harmful effect on cell growth and viability. Further, microscopic analysis validated the biofilm inhibitory efficacy of myrtenol against MRSA. In addition, myrtenol inhibited the synthesis of major virulence factors including slime, lipase, α-hemolysin, staphyloxanthin and autolysin. Inhibition of staphyloxanthin in turn sensitized the MRSA cells to healthy human blood and hydrogen peroxide (H2O2). Notably, myrtenol treated cells were deficient in extracellular DNA (eDNA) mediated autoaggregation as eDNA releasing autolysis was impaired by myrtenol. Biofilm disruptive activity on preformed biofilms was observed at concentrations higher than minimum biofilm inhibitory concentration (MBIC) of myrtenol. Also, the non-cytotoxic effect of myrtenol on human peripheral blood mononuclear cell (PBMC) was evidenced by trypan blue and Alamar blue assays. Transcriptional analysis unveiled the down-regulation of global regulator sarA and sarA mediated virulence genes upon myrtenol treatment, which is well correlated with results of phenotypic assays. Thus, the results of the present study revealed the sarA mediated antibiofilm and antivirulence potential of myrtenol against MRSA.},
}
@article {pmid31551940,
year = {2019},
author = {Bottagisio, M and Soggiu, A and Piras, C and Bidossi, A and Greco, V and Pieroni, L and Bonizzi, L and Roncada, P and Lovati, AB},
title = {Proteomic Analysis Reveals a Biofilm-Like Behavior of Planktonic Aggregates of Staphylococcus epidermidis Grown Under Environmental Pressure/Stress.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {1909},
doi = {10.3389/fmicb.2019.01909},
pmid = {31551940},
issn = {1664-302X},
abstract = {Prosthetic joint replacement failure has a huge impact on quality of life and hospitalization costs. A leading cause of prosthetic joint infection is bacteria-forming biofilm on the surface of orthopedic devices. Staphylococcus epidermidis is an emergent, low-virulence pathogen implicated in chronic infections, barely indistinguishable from aseptic loosening when embedded in a mature matrix. The literature on the behavior of quiescent S. epidermidis in mature biofilms is scarce. To fill this gap, we performed comparative analysis of the whole proteomic profiles of two methicillin-resistant S. epidermidis strains growing in planktonic and in sessile form to investigate the molecular mechanisms underlying biofilm stability. After 72-h culture of biofilm-forming S. epidermidis, overexpression of proteins involved in the synthesis of nucleoside triphosphate and polysaccharides was observed, whereas planktonic bacteria expressed proteins linked to stress and anaerobic growth. Cytological analysis was performed to determine why planktonic bacteria unexpectedly expressed proteins typical of sessile culture. Images evidenced that prolonged culture under vigorous agitation can create a stressful growing environment that triggers microorganism aggregation in a biofilm-like matrix as a mechanism to survive harsh conditions. The choice of a unique late time point provided an important clue for future investigations into the biofilm-like behavior of planktonic cells. Our preliminary results may inform comparative proteomic strategies in the study of mature bacterial biofilm. Finally, there is an increasing number of studies on the aggregation of free-floating bacteria embedded in an extracellular matrix, prompting the need to gain further insight into this mode of bacterial growth.},
}
@article {pmid31551455,
year = {2019},
author = {Valliammai, A and Sethupathy, S and Priya, A and Selvaraj, A and Bhaskar, JP and Krishnan, V and Pandian, SK},
title = {5-Dodecanolide interferes with biofilm formation and reduces the virulence of Methicillin-resistant Staphylococcus aureus (MRSA) through up regulation of agr system.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {13744},
pmid = {31551455},
issn = {2045-2322},
abstract = {Methicillin resistant Staphylococcus aureus (MRSA) is a predominant human pathogen with high morbidity that is listed in the WHO high priority pathogen list. Being a primary cause of persistent human infections, biofilm forming ability of S. aureus plays a pivotal role in the development of antibiotic resistance. Hence, targeting biofilm is an alternative strategy to fight bacterial infections. The present study for the first time demonstrates the non-antibacterial biofilm inhibitory efficacy of 5-Dodecanolide (DD) against ATCC strain and clinical isolates of S. aureus. In addition, DD is able to inhibit adherence of MRSA on human plasma coated Titanium surface. Further, treatment with DD significantly reduced the eDNA synthesis, autoaggregation, staphyloxanthin biosynthesis and ring biofilm formation. Reduction in staphyloxanthin in turn increased the susceptibility of MRSA to healthy human blood and H2O2 exposure. Quantitative PCR analysis revealed the induced expression of agrA and agrC upon DD treatment. This resulted down regulation of genes involved in biofilm formation such as fnbA and fnbB and up regulation of RNAIII, hld, psmα and genes involved in biofilm matrix degradation such as aur and nuc. Inefficacy of DD on the biofilm formation of agr mutant further validated the agr mediated antibiofilm potential of DD. Notably, DD was efficient in reducing the in vivo colonization of MRSA in Caenorhabditis elegans. Results of gene expression studies and physiological assays unveiled the agr mediated antibiofilm efficacy of DD.},
}
@article {pmid31551152,
year = {2019},
author = {Qi, M and Li, X and Sun, X and Li, C and Tay, FR and Weir, MD and Dong, B and Zhou, Y and Wang, L and Xu, HHK},
title = {Novel nanotechnology and near-infrared photodynamic therapy to kill periodontitis-related biofilm pathogens and protect the periodontium.},
journal = {Dental materials : official publication of the Academy of Dental Materials},
volume = {35},
number = {11},
pages = {1665-1681},
doi = {10.1016/j.dental.2019.08.115},
pmid = {31551152},
issn = {1879-0097},
mesh = {Biofilms ; Humans ; Nanotechnology ; *Periodontitis ; Periodontium ; *Photochemotherapy ; },
abstract = {OBJECTIVE: Periodontal tissue destruction and tooth loss are increasingly a worldwide problem as the population ages. Periodontitis is caused by bacterial infection and biofilm plaque buildup. Therefore, the objectives of this study were to: (1) develop a near-infrared light (NIR)-triggered core-shell nanostructure of upconversion nanoparticles and TiO2 (UCNPs@TiO2), and (2) investigate its inhibitory effects via antibacterial photodynamic therapy (aPDT) against periodontitis-related pathogens.<br><br>METHODS: The core β-NaYF4:Yb3+,Tm3+ were synthesized via thermal decomposition and further modified with the TiO2 shell via a hydrothermal method. The core-shell structure and the upconversion fluorescence-induced aPDT treatment via 980nm laser were studied. Three periodontitis-related pathogens Streptococcus sanguinis (S. sanguinis), Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) were investigated. The killing activity against planktonic bacteria was detected by a time-kill assay. Single species 4-day biofilms on dentin were tested by live/dead staining, colony-forming units (CFU), and metabolic activity.<br><br>RESULTS: The hexagonal shaped UCNPs@TiO2 had an average diameter of 39.7nm. UCNPs@TiO2 nanoparticles had positively charged (+12.4mV) surface and were biocompatible and non-cytotoxic. Under the excitation of NIR light (980nm), the core NaYF4:Yb3+,Tm3+ UCNPs could emit intense ultraviolet (UV) light, which further triggered the aPDT function of the shell TiO2 via energy transfer, thereby realizing the remarkable antibacterial effects against planktons and biofilms of periodontitis-associated pathogens. NIR-triggered UCNPs@TiO2 achieved much greater reduction in biofilms than control (p<0.05). Biofilm CFU was reduced by 3-4 orders of magnitude via NIR-triggered aPDT, which is significantly greater than that of negative control and commercial aPDT control groups. The killing efficacy of UCNPs@TiO2-based aPDT against the three species was ranked to be: S. sanguinis<F. nucleatum=P. gingivalis. Metabolic activities of biofilms were also greatly reduced via NIR-triggered aPDT (p<0.05).<br><br>SIGNIFICANCE: Upconversion fluorescence-based aPDT achieved strong inhibiting effects against all three species of periodontitis-related pathogens. This novel nanotechnology demonstrated a high promise to inhibit periodontitis, with exciting potential to combat other oral infectious diseases such as deep endodontic infections.},
}
@article {pmid31550929,
year = {2019},
author = {de Freitas, LM and Lorenzón, EN and Cilli, EM and de Oliveira, KT and Fontana, CR and Mang, TS},
title = {Photodynamic and peptide-based strategy to inhibit Gram-positive bacterial biofilm formation.},
journal = {Biofouling},
volume = {35},
number = {7},
pages = {742-757},
doi = {10.1080/08927014.2019.1655548},
pmid = {31550929},
issn = {1029-2454},
abstract = {The self-produced extracellular polymeric matrix of biofilms renders them difficult to eliminate once they are established. This makes the inhibition of biofilm formation key to successful treatment of biofilm infection. Antimicrobial photodynamic therapy (aPDT) and antimicrobial peptides offer a new approach as antibiofilm strategies. In this study sub-lethal doses of aPDT (with chlorin-e6 (Ce6-PDT) or methylene blue (MB-PDT)) and the peptides AU (aurein 1.2 monomer) or (AU)2K (aurein 1.2 C-terminal dimer) were combined to evaluate their ability to prevent biofilm development by Enterococcus faecalis. Biofilm formation was assessed by resazurin reduction, confocal microscopy, and infrared spectroscopy. All treatments successfully prevented biofilm development. The (AU)2K dimer had a stronger effect, both alone and combined with aPDT, while the monomer AU had significant activity when combined with Ce6-PDT. Additionally, it is shown that the peptides bind to the lipoteichoic acid of the E. faecalis cell wall, pointing to a possible key mechanism of biofilm inhibition.},
}
@article {pmid31550928,
year = {2019},
author = {Werner, BG and Wu, JY and Goddard, JM},
title = {Antimicrobial and antifouling polymeric coating mitigates persistence of Pseudomonas aeruginosa biofilm.},
journal = {Biofouling},
volume = {35},
number = {7},
pages = {785-795},
doi = {10.1080/08927014.2019.1660774},
pmid = {31550928},
issn = {1029-2454},
support = {S10 RR025502/RR/NCRR NIH HHS/United States ; },
abstract = {Food wasted due to food spoilage remains a global challenge to the environmental sustainability and security of food supply. In food manufacturing, post-processing contamination of food can occur due to persistent bacterial biofilms, which can be resistant to conventional cleaning and sanitization. The objective was to characterize the efficacy of a polymeric coating in reducing Pseudomonas aeruginosa biofilm establishment and facilitating its removal. Viable cell density of a 48 h biofilm was reduced by 2.10 log cfu cm-2 on the coated surface, compared to native polypropylene. Confocal laser scanning and electron microscopy indicated reductions in mature biofilm viability and thickness on the coated material. The antifouling coating improved cleanability, with ∼2.5 log cfu cm-2 of viable cells remaining after 105 min cleaning by water at 65 °C, compared to 4.5 log cfu cm-2 remaining on native polypropylene. Such coatings may reduce the persistence of biofilms in food processing environments, in support of reducing food spoilage and waste.},
}
@article {pmid31550124,
year = {2019},
author = {Hoque, J and Ghosh, S and Paramanandham, K and Haldar, J},
title = {Charge-Switchable Polymeric Coating Kills Bacteria and Prevents Biofilm Formation in Vivo.},
journal = {ACS applied materials &amp; interfaces},
volume = {11},
number = {42},
pages = {39150-39162},
doi = {10.1021/acsami.9b11453},
pmid = {31550124},
issn = {1944-8252},
abstract = {Preventing bacterial biofilm formation on medical devices and implants in vivo still remains a daunting task. Current antibacterial coatings to combat implant-associated infections are generally composed of toxic metals or nondegradable polymers and involve multistep surface modifications. Here, we present a charge-switchable antibacterial and antibiofilm coating based on water-insoluble cationic hydrophobic polymers that are soluble in organic solvents and can be noncovalently coated onto different surfaces. Toward this, a library of quaternary polyethylenimine (QPEI) polymers with an amide or ester group in their pendant alkyl chain was developed. These QPEIs are shown to hydrolyze from active cationic to nontoxic zwitterionic polymers under acidic or enzymatic conditions. Notably, polymers with both zwitterionic and cationic groups, obtained upon partial hydrolysis of QPEIs, are shown to retain their antibacterial activity with much lower toxicity toward mammalian cells. Furthermore, the zwitterionic polymer, a fully hydrolyzed product of the QPEIs, is shown to be nontoxic to mammalian cells in vitro as well as in vivo. The QPEIs, when coated onto surfaces, kill bacteria and prevent formation of biofilms. In an in vivo mice model, the QPEI-coated medical grade catheter is shown to reduce methicillin-resistant Staphylococcus aureus contamination both on the catheter surface and in the adjacent tissues (99.99% reduction compared to a noncoated catheter). Additionally, biofilm formation is inhibited on the catheter surface with negligible inflammation in the adjacent tissue. The above results thus highlight the importance of these polymers to be used as effective antibacterial coatings in biomedical applications.},
}
@article {pmid31548684,
year = {2019},
author = {Kowalski, CH and Kerkaert, JD and Liu, KW and Bond, MC and Hartmann, R and Nadell, CD and Stajich, JE and Cramer, RA},
title = {Fungal biofilm morphology impacts hypoxia fitness and disease progression.},
journal = {Nature microbiology},
volume = {4},
number = {12},
pages = {2430-2441},
doi = {10.1038/s41564-019-0558-7},
pmid = {31548684},
issn = {2058-5276},
support = {R01 AI130128/AI/NIAID NIH HHS/United States ; R01AI130128//U.S. Department of Health &amp; Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; MCB 1817342//NSF | BIO | Division of Molecular and Cellular Biosciences (MCB)/ ; F31AI138354//U.S. Department of Health &amp; Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; 5T32 GM 8704-20//U.S. Department of Health &amp; Human Services | NIH | National Institute of General Medical Sciences (NIGMS)/ ; T32 GM008704/GM/NIGMS NIH HHS/United States ; S10 OD016290/OD/NIH HHS/United States ; R01 AI081838/AI/NIAID NIH HHS/United States ; S10-OD016290//U.S. Department of Health &amp; Human Services | NIH | NIH Office of the Director (OD)/ ; P20-GM113132//U.S. Department of Health &amp; Human Services | NIH | National Institute of General Medical Sciences (NIGMS)/ ; F31 AI138354/AI/NIAID NIH HHS/United States ; 2R01AI081838//U.S. Department of Health &amp; Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)/ ; DBI-1429826//NSF | BIO | Division of Biological Infrastructure (DBI)/ ; Burke Award//Dartmouth College (Dartmouth)/ ; STANTO15RO//Cystic Fibrosis Foundation (CF Foundation)/ ; },
abstract = {Microbial populations form intricate macroscopic colonies with diverse morphologies whose functions remain to be fully understood. Despite fungal colonies isolated from environmental and clinical samples revealing abundant intraspecies morphological diversity, it is unclear how this diversity affects fungal fitness and disease progression. Here we observe a notable effect of oxygen tension on the macroscopic and biofilm morphotypes of the human fungal pathogen Aspergillus fumigatus. A hypoxia-typic morphotype is generated through the expression of a subtelomeric gene cluster containing genes that alter the hyphal surface and perturb interhyphal interactions to disrupt in vivo biofilm and infection site morphologies. Consequently, this morphotype leads to increased host inflammation, rapid disease progression and mortality in a murine model of invasive aspergillosis. Taken together, these data suggest that filamentous fungal biofilm morphology affects fungal-host interactions and should be taken into consideration when assessing virulence and host disease progression of an isolated strain.},
}
@article {pmid31548510,
year = {2019},
author = {Lin, Q and Sun, H and Yao, K and Cai, J and Ren, Y and Chi, Y},
title = {The Prevalence, Antibiotic Resistance and Biofilm Formation of Staphylococcus aureus in Bulk Ready-To-Eat Foods.},
journal = {Biomolecules},
volume = {9},
number = {10},
pages = {},
pmid = {31548510},
issn = {2218-273X},
abstract = {The prevalence of Staphylococcus aureus in 2160 bulk ready-to-eat foods from the Sichuan province of China during 2013-2016 was investigated. The antibiotic resistance and the associated genes, as well as biofilm formation capacity of the S. aureus isolates were measured. Furthermore, the relationship between the antibiotic resistance and the resistant genes was discussed. It was found that 54 S. aureus isolates were recovered, and their prevalence in meat products, dairy, fruit and vegetables, and desserts were 31 (2.6%), six (3.0%), nine (2.2%) and eight (2.3%), respectively. Most strains (52/54) were resistant to at least one of the antibiotics, and 21 isolates were identified as multidrug-resistant (MDR) S. aureus. Three isolates were found to be methicillin-resistant S. aureus. Penicillin, erythromycin, clindamycin, tetracycline and inducible clindamycin resistance were determined as the predominant antibiotics, and the isolates with the phenotypic resistance on these five antibiotics were all determined positive for the resistant gene associated. In total, 33 of 54 S. aureus isolates showed biofilm formation capacity, including two strong biofilm producers, one moderate and 30 weak ones. Two S. aureus isolates with strong biofilm formation abilities showed multi-drug resistance, and one moderate biofilm producer was resistant to two categories of antibiotics.},
}
@article {pmid31548325,
year = {2019},
author = {Ghimire, N and Pettygrove, BA and Pallister, KB and Stangeland, J and Stanhope, S and Klapper, I and Voyich, JM and Stewart, PS},
title = {Direct Microscopic Observation of Human Neutrophil-Staphylococcus aureus Interaction In Vitro Suggests a Potential Mechanism for Initiation of Biofilm Infection on an Implanted Medical Device.},
journal = {Infection and immunity},
volume = {87},
number = {12},
pages = {},
pmid = {31548325},
issn = {1098-5522},
support = {R01 GM109452/GM/NIGMS NIH HHS/United States ; R56 AI135039/AI/NIAID NIH HHS/United States ; },
abstract = {The ability of human neutrophils to clear newly attached Staphylococcus aureus bacteria from a serum-coated glass surface was examined in vitro using time-lapse confocal scanning laser microscopy. Quantitative image analysis was used to measure the temporal change in bacterial biomass, neutrophil motility, and fraction of the surface area policed by neutrophils. In control experiments in which the surface was inoculated with bacteria but no neutrophils were added, prolific bacterial growth was observed. Neutrophils were able to control bacterial growth but only consistently when the neutrophil/bacterium number ratio exceeded approximately 1. When preattached bacteria were given a head start and allowed to grow for 3 h prior to neutrophil addition, neutrophils were unable to maintain control of the nascent biofilm. In these head-start experiments, aggregates of bacterial biofilm with areas of 50 μm2 or larger formed, and the growth of such aggregates continued even when multiple neutrophils attacked a cluster. These results suggest a model for the initiation of a biofilm infection in which a delay in neutrophil recruitment to an abiotic surface allows surface-attached bacteria time to grow and form aggregates that become protected from neutrophil clearance. Results from a computational model of the neutrophil-biofilm surface contest supported this conceptual model and highlighted the stochastic nature of the interaction. Additionally, we observed that both neutrophil motility and clearance of bacteria were impaired when oxygen tension was reduced to 0% or 2% O2.},
}
@article {pmid31547513,
year = {2019},
author = {Erdmann, J and Thöming, JG and Pohl, S and Pich, A and Lenz, C and Häussler, S},
title = {The Core Proteome of Biofilm-Grown Clinical Pseudomonas aeruginosa Isolates.},
journal = {Cells},
volume = {8},
number = {10},
pages = {},
pmid = {31547513},
issn = {2073-4409},
support = {724290/ERC_/European Research Council/International ; },
abstract = {Comparative genomics has greatly facilitated the identification of shared as well as unique features among individual cells or tissues, and thus offers the potential to find disease markers. While proteomics is recognized for its potential to generate quantitative maps of protein expression, comparative proteomics in bacteria has been largely restricted to the comparison of single cell lines or mutant strains. In this study, we used a data independent acquisition (DIA) technique, which enables global protein quantification of large sample cohorts, to record the proteome profiles of overall 27 whole genome sequenced and transcriptionally profiled clinical isolates of the opportunistic pathogen Pseudomonas aeruginosa. Analysis of the proteome profiles across the 27 clinical isolates grown under planktonic and biofilm growth conditions led to the identification of a core biofilm-associated protein profile. Furthermore, we found that protein-to-mRNA ratios between different P. aeruginosa strains are well correlated, indicating conserved patterns of post-transcriptional regulation. Uncovering core regulatory pathways, which drive biofilm formation and associated antibiotic tolerance in bacterial pathogens, promise to give clues to interactions between bacterial species and their environment and could provide useful targets for new clinical interventions to combat biofilm-associated infections.},
}
@article {pmid31547458,
year = {2019},
author = {Zhang, XY and Sun, K and Abulimiti, A and Xu, PP and Li, ZY},
title = {Microfluidic System for Observation of Bacterial Culture and Effects on Biofilm Formation at Microscale.},
journal = {Micromachines},
volume = {10},
number = {9},
pages = {},
pmid = {31547458},
issn = {2072-666X},
support = {61674046//National Natural Science Foundation of China/ ; 2017TS04//State Key Laboratory of Urban Water Resource and Environment (Harbin Institute of Technology)/ ; },
abstract = {Biofilms exist in the natural world and applied to many industries. However, due to the variety of characteristics caused by their complex components, biofilms can also lead to membrane fouling and recurrent infections which pose threats to human health. So, to make the best use of their advantages and avoid their disadvantages, knowing the best time and methods for improving or preventing biofilm formation is important. In situ observation without fluorescence labeling in microscale and according to a time scale is useful to research biofilm and confine its formation. In this study, we developed a microfluidic system for real-time observation of bacteria culture and biofilms development at microscale. We cultured E. coli ATCC 25922 on a chip at continuous flow of the velocity, which could promote bacterial formation. Biofilms formation under the condition of adding amoxicillin at different times is also discussed. In addition, the mixed strains from sludge were also cultured on chip, and possible factors in biofilm formation are discussed. Our results show that a microfluidic device could culture microorganisms in continuous flow and accelerate them to adhere to the surface, thereby promoting biofilm formation. Overall, this platform is a useful tool in research on initial biofilm formation, which can contribute to preventing biofouling and infections.},
}
@article {pmid31547282,
year = {2019},
author = {Kerekes, EB and Vidács, A and Takó, M and Petkovits, T and Vágvölgyi, C and Horváth, G and Balázs, VL and Krisch, J},
title = {Anti-Biofilm Effect of Selected Essential Oils and Main Components on Mono- and Polymicrobic Bacterial Cultures.},
journal = {Microorganisms},
volume = {7},
number = {9},
pages = {},
pmid = {31547282},
issn = {2076-2607},
support = {4330//University of Szeged Open Access Fund/ ; },
abstract = {Biofilms are surface-associated microbial communities resistant to sanitizers and antimicrobials. Various interactions that can contribute to increased resistance occur between the populations in biofilms. These relationships are the focus of a range of studies dealing with biofilm-associated infections and food spoilage. The present study investigated the effects of cinnamon (Cinnamomum zeylanicum), marjoram (Origanum majorana), and thyme (Thymus vulgaris) essential oils (EOs) and their main components, i.e., trans-cinnamaldehyde, terpinen-4-ol, and thymol, respectively, on single- and dual-species biofilms of Escherichia coli, Listeria monocytogenes, Pseudomonas putida, and Staphylococcus aureus. In dual-species biofilms, L. monocytogenes was paired with each of the other three bacteria. Minimum inhibitory concentration (MIC) values for the individual bacteria ranged between 0.25 and 20 mg/mL, and trans-cinnamaldehyde and cinnamon showed the highest growth inhibitory effect. Single-species biofilms of L. monocytogenes, P. putida, and S. aureus were inhibited by the tested EOs and their components at sub-lethal concentrations. Scanning electron microscopy images showed that the three-dimensional structure of mature biofilms embedded in the exopolysaccharide matrix disappeared or was limited to micro-colonies with a simplified structure. In most dual-species biofilms, to eliminate living cells from the matrix, concentrations exceeding the MIC determined for individual bacteria were required.},
}
@article {pmid31546523,
year = {2019},
author = {Das, D and Bhattacharjee, H and Gogoi, K and Das, JK and Misra, P and Dhir, P and Deka, A},
title = {Intraocular lens biofilm formation supported by scanning electron microscopy imaging.},
journal = {Indian journal of ophthalmology},
volume = {67},
number = {10},
pages = {1708-1709},
pmid = {31546523},
issn = {1998-3689},
}
@article {pmid31546354,
year = {2019},
author = {Eduok, U and Ohaeri, E and Szpunar, J},
title = {Accelerated corrosion of pipeline steel in the presence of Desulfovibrio desulfuricans biofilm due to carbon source deprivation in CO2 saturated medium.},
journal = {Materials science &amp; engineering. C, Materials for biological applications},
volume = {105},
number = {},
pages = {110095},
doi = {10.1016/j.msec.2019.110095},
pmid = {31546354},
issn = {1873-0191},
abstract = {The chemistry of bacterial biofilms as well as the nutritional composition of culture environments may differ at any time within a growth process, especially for SRB consortia within oil wells with limited carbon sources. In the oilfield, the presence of SRB biofilms on surfaces of steel substrates leads to microbiologically influenced corrosion and compromised material integrity. In this work, the survival of SRB cells and their impact on the pipeline steel corrosion within simulated CO2-saturated oilfield-produced water with different concentrations of organic carbon source have been investigated. Cell counts reduced with the level of carbon source reduction (CSR) after incubation but more sessile cells survived at 80% CSR (moderate carbon starvation) compared to 100% CSR (extreme carbon starvation). The energy needed for cellular survival as well as biological support toward MIC could have been harnessed by a combination of extracellular Feo oxidation and intracellular sulfate reduction even after carbon source starvation. Severe anodic steel dissolution was observed at the end of the culture period within the simulated CO2-saturated oilfield-produced water, and this is attributed to SRB-led MIC and CO2 corrosion. Pipeline steel corroded more when cultured within 80% CSR compared to the medium with both lactate and citrate. Steel substrate corroded less with 100% CSR due to severely weakened SRB biofilms from nutrient deprivation.},
}
@article {pmid31546042,
year = {2019},
author = {Sales, LS and Guimarães, GN and Wijesinghe, GK and Moreira, KMS and Joia, F and Stipp, RN and Rodrigues, LKA and Nobre-Dos-Santos, M and Steiner-Oliveira, C},
title = {Addition of hydrogen peroxide to methylene blue conjugated to β-cyclodextrin in photodynamic antimicrobial chemotherapy in S. mutans biofilm.},
journal = {Photodiagnosis and photodynamic therapy},
volume = {28},
number = {},
pages = {226-233},
doi = {10.1016/j.pdpdt.2019.09.004},
pmid = {31546042},
issn = {1873-1597},
abstract = {OBJECTIVE: This study evaluated the effect of hydrogen peroxide addition on β-cyclodextrin-conjugated methylene blue in antimicrobial photodynamic therapy(a-PDT) in S. mutans biofilm model using laser or light emitting diode (LED) (λ = 660 nm).<br><br>METHODS: A preliminary assay was performed to evaluate the cytotoxicity of hydrogen peroxide in oral fibroblasts by the colorimetric method (MTT). Afterwards, groups were divided into (n = 3, in triplicate): C (negative control), CX - chlorhexidine 0.2% (positive control), P (methylene blue/β-cyclodextrin), H (Hydrogen Peroxide at 40 μM), PH, L (Laser), LP, LH (Laser+Hydrogen Peroxide), LPH, LED, LEDP, LEDH, and LEDPH. The biofilm was formed in 24 h with BHI + 1% sucrose (w/v). Light irradiations were conducted with laser, 9 J, 323 J/cm2, 113 s or with LED, 8.1 J, 8.1 J/cm2 for 90 s. Microbial reduction was evaluated by counting the viable microorganisms of the biofilm after the respective treatments, in a selective culture medium, and laser confocal microscopy evaluation.<br><br>RESULTS: LP, LH, LPH, LEDP, LEDH, and LEDPH groups statistically reduced the counts of S.mutans compared with the C group and the log reductions were of 1.87, 1.94, 2.19, 0.91, 0.92, and 1.33, respectively; the addition of hydrogen peroxide did not potentiate the microbial reductions (LPH and LEDPH) compared with the LP and LEDP groups.<br><br>CONCLUSION: The association of hydrogen peroxide with the conjugated β-cyclodextrin nanoparticle as photosensitizer did not result in an enhanced effect of a-PDT; hydrogen peroxide behaved as a photosensitizer, since it reduced the number of S. mutans when associated with laser light.},
}
@article {pmid31546040,
year = {2019},
author = {Ram, MK and Naveen Kumar, BT and Poojary, SR and Abhiman, PB and Patil, P and Ramesh, KS and Shankar, KM},
title = {Evaluation of biofilm of Vibrio anguillarum for oral vaccination of Asian seabass, Lates calcarifer (BLOCH, 1790).},
journal = {Fish &amp; shellfish immunology},
volume = {94},
number = {},
pages = {746-751},
doi = {10.1016/j.fsi.2019.09.053},
pmid = {31546040},
issn = {1095-9947},
abstract = {The present study evaluated the biofilm (BF) of Vibrio anguillarum for oral vaccination of Asian seabass, Lates calcarifer. An 80-day experiment was carried out in circular fiber-reinforced plastic (FRP) tanks using free cell (FC) and BF of Vibrio anguillarum with triplicate in each. Heat-inactivated FC and BF cells at 107, 1010 and 1013 CFU/g fish/d were fed to fish for 20 days, agglutination antibody titer estimated at each 10 days interval up to 60-day post vaccination. As compared to FC and control there was a significant increase in agglutinating antibody titer in the biofilm vaccinated fishes. Among the 3 doses, BF at 1010 cfu/g fish/d was considered the ideal dose for vaccination. Relative percentage survival (RPS) was higher in biofilm vaccinated fish (85.4%) compared to that with free cells (27.0%). The study demonstrated the better performance of V. anguillarum biofilm oral vaccine compared that with free cell vaccine in L. calcarifer. The study further supports better performance of biofilm vaccine model with one more bacterial pathogen in a high carnivore fish.},
}
@article {pmid31546000,
year = {2019},
author = {Campos-Silva, R and Brust, FR and Trentin, DS and Macedo, AJ},
title = {Alternative method in Galleria mellonella larvae to study biofilm infection and treatment.},
journal = {Microbial pathogenesis},
volume = {137},
number = {},
pages = {103756},
doi = {10.1016/j.micpath.2019.103756},
pmid = {31546000},
issn = {1096-1208},
abstract = {In vivo studies are crucial decision-maker step in order to translate in vitro data to an applied therapy. Considering this we describe a simple method that analyzes and quantifies biofilm formation inside the Galleria mellonella larvae. Toothbrush bristles were employed as an abiotic surface to mimic a medical device. A standardized inoculum of Staphylococcus aureus was systemically injected in the larvae together with the insertion of a bristle in the last proleg pair. After incubation adhered cells were detached from bristles and quantified by colony-forming units (CFU) counting using staphylococci-selective medium. About 3 × 106 CFU of S. aureus were recovered from bristles and scanning electron microscopy (SEM) images confirmed biofilm formation. Control group did not show adherent bacteria, as demonstrated by absence of CFU counting and SEM images, indicating that the insertion procedure is free of bacterial contamination. We present a feasible method to evaluate bacterial biofilm formation in vivo that in the near future can be used to evaluate antibiofilm compounds.},
}
@article {pmid31543874,
year = {2019},
author = {De Carolis, E and Soldini, S and La Rosa, M and Nucci, F and Posteraro, B and Sanguinetti, M},
title = {BIOF-HILO Assay: A New MALDI-TOF Mass Spectrometry Based Method for Discriminating Between High- and Low-Biofilm-Producing Candida parapsilosis Isolates.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2046},
doi = {10.3389/fmicb.2019.02046},
pmid = {31543874},
issn = {1664-302X},
abstract = {Candida parapsilosis is the most frequent cause of catheter-related candidemia among non-Candida albicans species. This may be related to intrinsic capabilities as adhering and forming a biofilm on abiotic surfaces such as on medical devices. As previously demonstrated, patients infected with high biofilm-producing C. parapsilosis isolates had a greater mortality risk compared to patients infected with low biofilm-producing C. parapsilosis isolates. We developed the BIOF-HILO assay, a MALDI-TOF mass spectrometry (MS)-based assay, which compares mass spectra obtained from attached and suspended isolate cells during the early (i.e., 3-h) adhesion phase of in vitro biofilm formation. The composite correlation index (CCI) analysis was used to discriminate between mass spectra differences of the two cell types, classifying all 50 C. parapsilosis clinical isolates, included in the study, after only 3-h of testing, in high or low biofilm producers. All high (n = 25) or low (n = 25) biofilm producers had, according to CCI mass spectra comparison values, higher or lower than one CCI ratios, which were obtained by dividing the CCIsuspended cells by the CCIattached cells. In conclusion, the BIOF-HILO assay allows a rapid categorization of C. parapsilosis clinical isolates in high or low biofilm producers. This information, if timely provided to physicians, may improve treatment outcomes in patients with C. parapsilosis candidemia.},
}
@article {pmid31543873,
year = {2019},
author = {Alviz-Gazitua, P and Fuentes-Alburquenque, S and Rojas, LA and Turner, RJ and Guiliani, N and Seeger, M},
title = {Corrigendum: The Response of Cupriavidus metallidurans CH34 to Cadmium Involves Inhibition of the Initiation of Biofilm Formation, Decrease in Intracellular c-di-GMP Levels, and a Novel Metal Regulated Phosphodiesterase.},
journal = {Frontiers in microbiology},
volume = {10},
number = {},
pages = {2014},
doi = {10.3389/fmicb.2019.02014},
pmid = {31543873},
issn = {1664-302X},
abstract = {[This corrects the article DOI: 10.3389/fmicb.2019.01499.].},
}
@article {pmid31543653,
year = {2019},
author = {Kitti, T and Seng, R and Thummeepak, R and Boonlao, C and Jindayok, T and Sitthisak, S},
title = {Biofilm Formation of Methicillin-resistant Coagulase-Negative Staphylococci Isolated from Clinical Samples in Northern Thailand.},
journal = {Journal of global infectious diseases},
volume = {11},
number = {3},
pages = {112-117},
doi = {10.4103/jgid.jgid_118_18},
pmid = {31543653},
issn = {0974-777X},
abstract = {Background: Methicillin-resistant coagulase-negative staphylococci (MR-CoNS) are multidrug-resistant bacteria that are difficult to treat because of their ability to form biofilms.<br><br>Objectives: In the present study, we evaluated the antibiotic-resistant phenotypes, biofilm-forming ability, and biofilm associated genes of 55 clinical MR-CoNS isolates obtained from two hospitals in Thailand.<br><br>Materials and Methods: MALDI-TOF-MS and tuf gene sequencing were performed to determine the species of all isolates. Biofilm production was determined using Congo red agar (CRA) and the microtiter plate (MTP) assay. Biofilm-associated genes were characterized using polymerase chain reaction (PCR).<br><br>Results: Among the 55 MR-CoNS isolates, five species were identified as Staphylococcus haemolyticus (34.5%), Staphylococcus epidermidis (32.7%), Staphylococcus capitis (18.2%), Staphylococcus cohnii (9.1%), and Staphylococcus hominis (5.5%). The antimicrobial susceptibility pattern of MR-CoNS isolates indicated high resistance to cefoxitin (100%), penicillin (98.2%), erythromycin (96.4%), ciprofloxacin (67.3%), sulfamethoxazole/trimethoprim (67.3%), gentamicin (67.3%), and clindamycin (63.6%). All the isolates were susceptible to vancomycin and linezolid. The biofilm production was detected in 87.3% isolates through the CRA method and in 38.1% isolates through the MTP assay. The prevalence rates of icaAD, bap, fnbA, and cna were 18.2%, 12.7%, 47.3%, and 27.3%, respectively. There were significant differences in the presence of these biofilm-associated genes among the MR-CoNS isolates. Moreover, quantitative biofilm formation was significantly different among MR-CoNS species.<br><br>Conclusion: The present study revealed that biofilm-associated genes are important for biofilm biomass in MR-CoNS isolates, and the findings of this study are essential for finding new strategies to control biofilm formation and prevent the spread of MR-CoNS infectious diseases.},
}
@article {pmid31542601,
year = {2019},
author = {Mitchell, K and Lima, AT and Van Cappellen, P},
title = {Selenium in buoyant marine debris biofilm.},
journal = {Marine pollution bulletin},
volume = {149},
number = {},
pages = {110562},
doi = {10.1016/j.marpolbul.2019.110562},
pmid = {31542601},
issn = {1879-3363},
abstract = {Marine debris is widespread in all the world's oceans. Currently little is understood about how marine debris affects the chemistry of the surface oceans, particularly trace elements that can adsorb to the surface of marine debris, especially plastic debris, or be taken up by biofilms and algae growing on the surface of marine debris. Selenium (Se) is a micronutrient that is essential to all living organisms. Average seawater Se concentrations in the modern ocean are <1 nM. Here we measure the concentration of Se in surface water and one deep water sample and the concentration of Se found in algae/biofilms growing on the surface of macro-debris collected in October of 2012. Concentrations of Se in biofilm varied more according to the type of biofilm rather than the type of plastic. However, further Se measurements are needed for more conclusive results.},
}
@article {pmid31542551,
year = {2019},
author = {Acevedo Alonso, V and Lackner, S},
title = {Membrane Aerated Biofilm Reactors - How longitudinal gradients influence nitrogen removal - A conceptual study.},
journal = {Water research},
volume = {166},
number = {},
pages = {115060},
doi = {10.1016/j.watres.2019.115060},
pmid = {31542551},
issn = {1879-2448},
mesh = {Biofilms ; *Bioreactors ; Denitrification ; *Nitrogen ; Waste Disposal, Fluid ; },
abstract = {Membrane-aerated biofilm reactors are becoming more important for nitrogen removal in the wastewater sector. One-dimensional (1D) models are widely used to study the performance of such systems; however, 1D models are not able to simulate the longitudinal gradients that exist in the reactor. Although there is experimental evidence that points to the existence of longitudinal gradients simple modeling approaches that consider these gradients are not yet developed. This study proposes a novel multi-compartment model that simulates the longitudinal substrate and oxygen gradients. It assesses the effects of temperature, biofilm thickness, number of compartments, and flow configuration (liquid and gas phase) on the modeling results. Additionally, it compares the capabilities of a traditional 1D model with those of the novel multi-compartment model. Our results show that a classical 1D model predicts a lower total dissolved nitrogen concentration (TDN) in the effluent in contrast to the predictions of the multi-compartment model. In the worst-case scenario, the TDN predicted by the traditional 1D model was three times lower than the prediction of the multi-compartment model. The results delivered by the models differ also in the axial gradients. The traditional 1D model, for example, predicted an oxygen concentration at the membrane surface of 0.4 mg-O2/l while the multi-compartment model predicted a concentration of 2.9 mg-O2/l. Finally, the results of this study show that the longitudinal oxygen gradient has an important effect on both, biomass distribution and effluent TDN, whereas the longitudinal substrate exclusively affected the effluent TDN.},
}
@article {pmid31541515,
year = {2019},
author = {Amaechi, BT and Abdul Azees, PA and Menon, S and Kasundra, H},
title = {In vitro evaluation of the effects of Ultrasound Tongue Scraper on bacteria and biofilm formation.},
journal = {Journal of investigative and clinical dentistry},
volume = {10},
number = {4},
pages = {e12471},
doi = {10.1111/jicd.12471},
pmid = {31541515},
issn = {2041-1626},
support = {//Starmoon/ ; },
mesh = {Bacteria ; *Biofilms ; Microscopy, Confocal ; *Tannerella forsythia ; },
abstract = {AIM: Oral malodor is a common condition caused by some Gram-negative oral bacteria, among which are the 3 red complex bacteria (RCB). The present study investigated the effectiveness of the Ultrasound Tongue Scraper (UTS) to disrupt the structural morphology of the bacteria and their biofilm.<br><br>METHODS: While developing over 72 hours, multispecies biofilms of RCB (Porphromonas gingivalis, Tryponema denticola, Tannerella forsythia) were treated every 24 hours with 1.6-MHz ultrasound waves generated with UTS. An untreated group served as controls. Confocal laser scanning microscopy was used to determine the biofilm thickness, biomass and live : dead cell ratio at each time point (24, 48 and 72 hours). Biofilm morphology and bacteria ultrastructure were viewed using scanning/transmission electron microscopy, respectively. Data were analyzed using ANOVA and Tukey tests.<br><br>RESULTS: At each time point, the 3 variables were significantly lower in treated samples than the untreated. Significant biofilm disruption was observed in treated samples at each time period while the untreated had intact biofilm morphology. Cells in treated samples showed disrupted cell wall, cytoplasmic material, huge vacuoles and heterogeneity in electron density, while these cell organelles remained intact in untreated samples.<br><br>CONCLUSION: The UTS has an inhibitory effect on RCB and could be useful for oral malodor management.},
}
@article {pmid31540110,
year = {2019},
author = {Li, S and Wang, Y and Li, X and Lee, BS and Jung, S and Lee, MS},
title = {Enhancing the Thermo-Stability and Anti-Biofilm Activity of Alginate Lyase by Immobilization on Low Molecular Weight Chitosan Nanoparticles.},
journal = {International journal of molecular sciences},
volume = {20},
number = {18},
pages = {},
pmid = {31540110},
issn = {1422-0067},
support = {NRF-2016R1A5A1011974//National Research Foundation of Korea (NRF)/ ; MBSMAT-2019-02//Key Lab of Marine Bioactive Substance and Modern Analytical Technique (SOA)/ ; ZR2019BD027//Shandong Provincial Natural Science Foundation/ ; KLGGOUC201703//Open Research Fund Program of Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology (Ocean University of China)/ ; },
abstract = {Bacterial biofilm causes severe antibiotic resistance. An extracellular polymeric substance (EPS) is the main component in the bacterial biofilm. Alginate is a key EPS component in the biofilm of Pseudomonas aeruginosa and responsible for surface adhesion and stabilization of biofilm. Alginate lyase has emerged as an efficient therapeutic strategy targeting to degrade the alginate in the biofilm of P. aeruginosa. However, the application of this enzyme is limited by its poor stability. In this study, chitosan nanoparticles (CS-NPs) were synthesized using low molecular weight chitosan and alginate lyase Aly08 was immobilized on low molecular weight chitosan nanoparticles (AL-LMW-CS-NPs). As a result, the immobilization significantly enhanced the thermal stability and reusability of Aly08. In addition, compared with free Aly08, the immobilized AL-LMW-CS-NPs exhibited higher efficiency in inhibiting biofilm formation and interrupting the established mature biofilm of P. aeruginosa, which could reduce its biomass and thickness confirmed by confocal microscopy. Moreover, the biofilm disruption greatly increased the antibiotic sensitivity of P. aeruginosa. This research will contribute to the further development of alginate lyase as an anti-biofilm agent.},
}
@article {pmid31539943,
year = {2019},
author = {Wang, X and Liu, B and Pan, X and Gadd, GM},
title = {Transport and retention of biogenic selenium nanoparticles in biofilm-coated quartz sand porous media and consequence for elemental mercury immobilization.},
journal = {The Science of the total environment},
volume = {692},
number = {},
pages = {1116-1124},
doi = {10.1016/j.scitotenv.2019.07.309},
pmid = {31539943},
issn = {1879-1026},
mesh = {Biofilms ; Hydrophobic and Hydrophilic Interactions ; Mercury/*analysis ; *Models, Chemical ; Nanoparticles/*analysis/chemistry ; Quartz ; Selenium/*analysis/chemistry ; },
abstract = {Bacterial biofilms are structured cell communities embedded in a matrix of extracellular polymeric substances (EPS) and a ubiquitous growth form of bacteria in the environment. A wide range of interactions between biofilms and nanoparticles have been reported. In the present study, the influence of a mixed bacterial biofilm on retention of biogenic selenium nanoparticles (BioSeNPs) and consequences for immobilization of elemental mercury (Hg0) in a porous quartz sand system were examined. BioSeNPs were significantly retained in the presence of a biofilm through electrical double layer effects, hydrogen bonding, and hydrophobic, steric and bridging interactions. Moreover, enhanced surface roughness, pore clogging, sieving and entrapment effects mediated by the biofilm also contributed to deposition of BioSeNPs. Whereas, thiol groups associated with the biofilm is a little helpful for the capture of Hg0. It is proposed that oxidative complexation between Hg0 and thiol compounds or S containing organic matter in the biofilm may result in the formation of Hg2+-thiolate complexes and HgS during the binding of Hg0 with BioSeNPs. The formation of mercury selenide was also involved in Hg0 immobilization in the porous quartz sand system.},
}
@article {pmid31539312,
year = {2019},
author = {Cai, X and Yao, L and Sheng, Q and Jiang, L and Wang, T and Dahlgren, RA and Deng, H},
title = {Influence of a biofilm bioreactor on water quality and microbial communities in a hypereutrophic urban river.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-9},
doi = {10.1080/09593330.2019.1670267},
pmid = {31539312},
issn = {1479-487X},
abstract = {Biofilms play an important role in degradation, transformation and assimilation of anthropogenic pollutants in aquatic ecosystems. In this study, we assembled a tubular bioreactor containing a biofilm substrate and aeration device, which was introduced into mesocosms to explore the effects of bioreactor on physicochemical and microbial characteristics of a hypereutrophic urban river. The biofilm bioreactor greatly improved water quality, especially by decreasing dissolved inorganic nitrogen (DIN) concentrations, suggesting that biofilms were the major sites of nitrification and denitrification with an oxygen concentration gradient. The biofilm bioreactor increased the abundance of planktonic bacteria, whereas diversity of the planktonic microbial community decreased. Sequencing revealed that Proteobacteria, Bacteroidetes, Planctomycetes, and Actinobacteria were the four predominant phyla in the planktonic microbial community, and the presence of the biofilm bioreactor increased the relative abundance of Proteobacteria. Variations in microbial communities were most strongly affected by the presence of the biofilm bioreactor, as indicated by principal component analysis (PCA) and redundancy analysis (RDA). This study provides valuable insights into changes in ecological characteristics associated with self-purification processes in hypereutrophic urban rivers, and may be of important for the application of biofilm bioreactor in natural urban river.},
}
@article {pmid31537970,
year = {2019},
author = {Bali, EB and Türkmen, KE and Erdönmez, D and Sağlam, N},
title = {Comparative Study of Inhibitory Potential of Dietary Phytochemicals Against Quorum Sensing Activity of and Biofilm Formation by Chromobacterium violaceum 12472, and Swimming and Swarming Behaviour of Pseudomonas aeruginosa PAO1.},
journal = {Food technology and biotechnology},
volume = {57},
number = {2},
pages = {212-221},
doi = {10.17113/ftb.57.02.19.5823},
pmid = {31537970},
issn = {1330-9862},
abstract = {Quorum sensing (QS) and biofilm formation are important mechanisms related to antibiotic resistance of many pathogens. Alternative treatments are needed to prevent recurrent or chronic infections caused by multi-resistant pathogens. Therefore, the aim of this study is to investigate and compare the inhibitory potential of the dietary phytochemicals: curcumin, quercetin, apigenin, pyrogallol, gallic acid and luteolin against QS of and biofilm formation by Chromobacterium violaceum ATCC 12472 and the swimming and swarming abilities of Pseudomonas aeruginosa PAO1. Anti-QS potential of the phytochemicals was evaluated qualitatively and quantitatively using C. violaceum via the disk diffusion assay based on violacein pigment inhibition at the subminimal inhibitory concentrations ranging from 46.87 to 750 µg/mL. The results of anti-QS and antibiofilm activities on C. violaceum demonstrated that all the phytochemicals except pyrogallol and gallic acid inhibited violacein production (from (11.0±0.1) to (88.2±0.1) %) in a concentration-dependent manner. In addition, the biofilm formation was also significantly inhibited (p<0.05) in the presence of all the phytochemicals ((1.38±0.08)-(84.2±0.2) %). In the present study, the results revealed that quercetin, curcumin, apigenin and luteolin could be promising QS and biofilm inhibitory agents against the C. violaceum 12472 biosensor system. Our findings also suggest that all the phytochemicals, especially curcumin, quercetin and pyrogallol, might be anti-pathogenic agents against P. aeruginosa PAO1 infections due to the ability to control QS. However, more comprehensive studies at the molecular level, explaining their anti-QS mechanisms, need to be conducted to confirm these results and identify the genes involved.},
}
@article {pmid31536440,
year = {2019},
author = {Abushahba, F and Söderling, E and Aalto-Setälä, L and Hupa, L and Närhi, TO},
title = {Air-Abrasion with bioactive glass eradicates S. mutans biofilm from sandblasted and acid etched titanium surface.},
journal = {The Journal of oral implantology},
volume = {},
number = {},
pages = {},
doi = {10.1563/aaid-joi-D-18-00324},
pmid = {31536440},
issn = {0160-6972},
abstract = {Streptococcus mutans is able to form a high-affinity biofilm on material surfaces. S. mutans has also been detected around infected implants. Bioactive glasses have been shown to possess antibacterial effects against S. mutans and other microorganisms. This in vitrostudy was performed to investigate the influence of bioactive glass air-abrasion on S. mutans biofilm on sandblasted and acid etched titanium surfaces. Sandblasted and acid etched commercially pure titanium discs were used as substrates for bacteria (n=107). The discs were immersed in an S. mutans solution and incubated for 21 h to form S. mutans biofilm. Twenty colonized discs were subjected to air-abrasion with the Bioglass®45S5 (45S5 BAG), experimental zinc oxide containing bioactive glass (Zn4 BAG) and inert glass. After the abrasion, the discs were incubated for 5 h in an anaerobic chamber followed by an assessment of viable S. mutans cells. Surface morphology was evaluation using SEM (n=12). Thrombogenicity of the glass particle abraded discs (n=75) was evaluated spectrophotometrically using whole blood clotting measurement at predetermined time points. Air-abrasion with 45S5 and Zn4 bioactive glass eradicated S. mutans biofilm. Significantly less viable S. mutans cells were found on discs abraded with the 45S5 or Zn4 BAGs compared to the inert glass (p<0.001). No significant differences were found in thrombogenicity since blood clotting was achieved for all substrates in min 40. Air-abrasion with BAG particles is effective in the eradication of S. mutans biofilm from sandblasted and acid etched titanium surfaces. Zn4 and 45S5 BAGs had similar biofilm eradicating effects but the Zn4 BAG could be more tissue-friendly. In addition, the steady release of zinc ions from the Zn4 may enhance the bone regeneration around the titanium implant and may thus have the potential to be used in the treatment of peri-implantitis. The use of either BAGs did not enhance the speed of blood coagulation.},
}
@article {pmid31535222,
year = {2019},
author = {Mello, DCR and de Oliveira, JR and Cairo, CAA and Ramos, LSB and Vegian, MRDC and de Vasconcellos, LGO and de Oliveira, FE and de Oliveira, LD and de Vasconcellos, LMR},
title = {Titanium alloys: in vitro biological analyzes on biofilm formation, biocompatibility, cell differentiation to induce bone formation, and immunological response.},
journal = {Journal of materials science. Materials in medicine},
volume = {30},
number = {9},
pages = {108},
doi = {10.1007/s10856-019-6310-2},
pmid = {31535222},
issn = {1573-4838},
support = {2012/20311-8//Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)/ ; },
abstract = {Biological effects of titanium (Ti) alloys were analyzed on biofilms of Candida albicans, Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans, and Streptococcus sanguinis, as well as on osteoblast-like cells (MG63) and murine macrophages (RAW 264.7). Standard samples composed of aluminum and vanadium (Ti-6Al-4V), and sample containing niobium (Ti-35Nb) and zirconium (Ti-13Nb-13Zr) were analyzed. Monomicrobial biofilms were formed on the Ti alloys. MG63 cells were grown with the alloys and the biocompatibility (MTT), total protein (TP) level, alkaline phosphatase (ALP) activity, and mineralization nodules (MN) formation were verified. Levels of interleukins (IL-1β and IL-17), tumor necrosis factor alpha (TNF-α), and oxide nitric (NO) were checked, from RAW 264.7 cells supernatants. Data were statically analyzed by one-way analysis of variance (ANOVA) and Tukey's test, or T-test (P ≤ 0.05). Concerning the biofilm formation, Ti-13Nb-13Zr alloy showed the best inhibitory effect on E. faecalis, P. aeruginosa, and S. aureus. And, it also acted similarly to the Ti-6Al-4V alloy on C. albicans and Streptococcus spp. Both alloys were biocompatible and similar to the Ti-6Al-4V alloy. Additionally, Ti-13Nb-13Zr alloy was more effective for cell differentiation, as observed in the assays of ALP and MN. Regarding the stimulation for release of IL-1β and TNF-α, Ti-35Nb and Ti-13Nb-13Zr alloys inhibited similarly the synthesis of these molecules. However, both alloys stimulated the production of IL-17. Additionally, all Ti alloys showed the same effect for NO generation. Thus, Ti-13Nb-13Zr alloy was the most effective for inhibition of biofilm formation, cell differentiation, and stimulation for release of immune mediators.},
}
@article {pmid31535132,
year = {2019},
author = {Oktay, EA and Ersahan, S and Sabuncuoglu, FA and Tort, H and Karaoglanoglu, S},
title = {Impact of various finishing and polishing techniques and composite materials on Candida albicans biofilm formation.},
journal = {Medical mycology},
volume = {},
number = {},
pages = {},
doi = {10.1093/mmy/myz095},
pmid = {31535132},
issn = {1460-2709},
abstract = {Candida albicans biofilms are commonly associated with severe oral infections. In dentistry, prosthetic and restorative materials are potential structures for the adhesion of C. albicans facilitating the formation of Candida biofilm and infection. Three composite resins (Charisma Classic, Sonic Fill, Estelite ∑ Quick) and two finishing-polishing systems (Biscover LV, Dental Finishing Disc) were evaluated for Candida biofilm formation. A Candida biofilm assay showed that both the resin and the finishing/polishing procedures affect Candida biofilm formation. Specifically, Candida biofilm formation was significantly lower in Sonic Fill resin than both Charisma Classic and Estelite ∑ Quick (P = .021). The type of finishing and polishing procedure also significantly affected the Candida biofilm formation to composite material (P < .001). Candida biofilm formation was more advanced after Biscover LV procedure than Dental Finishing Disc procedure.},
}
@article {pmid31534648,
year = {2019},
author = {Craft, KM and Nguyen, JM and Berg, LJ and Townsend, SD},
title = {Methicillin-resistant Staphylococcus aureus (MRSA): antibiotic-resistance and the biofilm phenotype.},
journal = {MedChemComm},
volume = {10},
number = {8},
pages = {1231-1241},
doi = {10.1039/c9md00044e},
pmid = {31534648},
issn = {2040-2511},
abstract = {Staphylococcus aureus (S. aureus) is an asymptomatic colonizer of 30% of all human beings. While generally benign, antibiotic resistance contributes to the success of S. aureus as a human pathogen. Resistance is rapidly evolved through a wide portfolio of mechanisms including horizontal gene transfer and chromosomal mutation. In addition to traditional resistance mechanisms, a special feature of S. aureus pathogenesis is its ability to survive on both biotic and abiotic surfaces in the biofilm state. Due to this characteristic, S. aureus is a leading cause of human infection. Methicillin-resistant S. aureus (MRSA) in particular has emerged as a widespread cause of both community- and hospital-acquired infections. Currently, MRSA is responsible for 10-fold more infections than all multi-drug resistant (MDR) Gram-negative pathogens combined. Recently, MRSA was classified by the World Health Organization (WHO) as one of twelve priority pathogens that threaten human health. In this targeted mini-review, we discuss MRSA biofilm production, the relationship of biofilm production to antibiotic resistance, and front-line techniques to defeat the biofilm-resistance system.},
}
@article {pmid31533204,
year = {2019},
author = {Weng, PL and Ramli, R and Hamat, RA},
title = {Antibiotic Susceptibility Patterns, Biofilm Formation and esp Gene among Clinical Enterococci: Is There Any Association?.},
journal = {International journal of environmental research and public health},
volume = {16},
number = {18},
pages = {},
doi = {10.3390/ijerph16183439},
pmid = {31533204},
issn = {1660-4601},
abstract = {Enterococci are commonly found in humans, animals and environments. Their highly adaptive mechanisms are related to several virulent determinants and their ability to resist antibiotics. Data on the relationship between the esp gene, biofilm formation and antibiotic susceptibility profiles may differ between countries. This cross-sectional study was conducted to determine the proportion of esp gene and biofilm formation among Enterococcus faecalis and Enterococcus faecium clinical isolates. We also investigated the possible association between the esp gene with antibiotic susceptibility patterns and biofilm formation. The isolates were collected from clinical samples and identified using biochemical tests and 16SRNA. Antibiotic susceptibility patterns and a biofilm assay were conducted according to the established guidelines. Molecular detection by PCR was used to identify the esp gene using established primers. In total, 52 and 28 of E. faecalis and E. faecium were identified, respectively. E. faecium exhibited higher resistance rates compared to E. faecalis as follows: piperacillin/tazobactam (100% versus 1.9%), ampicillin (92.8% versus 1.9%), high-level gentamicin resistance (HLGR) (89.3% versus 25.0%) and penicillin (82.1% versus 7.7%). E. faecium produced more biofilms than E. faecalis (59.3% versus 49.0%). E. faecium acquired the esp gene more frequently than E. faecalis (78.6% versus 46.2%). Interestingly, the associations between ampicillin and tazobactam/piperacillin resistance with the esp gene were statistically significant (X2 = 4.581, p = 0.027; and X2 = 6.276, p = 0.012, respectively). Our results demonstrate that E. faecium exhibits high rates of antimicrobial resistance, esp gene acquisition and biofilm formation. These peculiar traits of E. faecium may have implications for the management of enterococcal infections in hospitals. Thus, concerted efforts by all parties in establishing appropriate treatment and effective control measures are warranted in future.},
}
@article {pmid31533083,
year = {2019},
author = {Preetham, E and Rubeena, AS and Vaseeharan, B and Chaurasia, MK and Arockiaraj, J and Olsen, RE},
title = {Anti-biofilm properties and immunological response of an immune molecule lectin isolated from shrimp Metapenaeus monoceros.},
journal = {Fish &amp; shellfish immunology},
volume = {94},
number = {},
pages = {896-906},
doi = {10.1016/j.fsi.2019.09.032},
pmid = {31533083},
issn = {1095-9947},
abstract = {The study is carried out to understand the antimicrobial and immunological response of a potential immune molecule lectin, MmLec isolated from haemolymph of Speckled shrimp, Metapenaeus monoceros. MmLec was purified using mannose coupled Sepharose CL-4B affinity chromatography, which was further subjected on SDS-PAGE to ascertain the distribution of their molecular weight. Sugar binding specificity assay was conducted at various pH and temperatures to investigate the binding affinity of MmLec towards the specific carbohydrate molecule. Functional analysis of immune molecule MmLec included haemagglutination assays performed using human erythrocytes and yeast agglutination activity against Saccharomyces cerevisiae which, were analyzed using light microscopy. In order to study the antimicrobial activity, two Gram-negative (Vibrio parahaemolyticus and Aeromonas hydrophila) and two Gram-positive (Staphylococcus aureus and Enterococcus faecalis) bacteria were treated with purified MmLec. Moreover, these bacterial species were also treated at different concentration of the MmLec to speculate the antibiofilm properties of MmLec which was analyzed under Light Microscopy and Confocal Laser Scanning Microscopy. In addition, other functional characterization of MmLec showed the uniqueness of MmLec in agglutination of human erythrocyte as well as the cells of yeast Saccharomyces cerevisiae. Also, the phenoloxidase activity and encapsulation assay was evaluated. MTT assay displayed that MmLec are potent in anticancer activity. The study will help to understand the immunological interference and antimicrobial nature of MmLec which would be supportive in establishing a potential therapeutic tool and to develop better and novel disease control strategies in shrimp and farmed aquaculture industries as well as in health management.},
}
@article {pmid31533077,
year = {2020},
author = {Vijayakumar, K and Ramanathan, T},
title = {Musa acuminata and its bioactive metabolite 5-Hydroxymethylfurfural mitigates quorum sensing (las and rhl) mediated biofilm and virulence production of nosocomial pathogen Pseudomonas aeruginosa in vitro.},
journal = {Journal of ethnopharmacology},
volume = {246},
number = {},
pages = {112242},
doi = {10.1016/j.jep.2019.112242},
pmid = {31533077},
issn = {1872-7573},
abstract = {Musa acuminata, a tropical plant belongs to the family Musaceae. The fruit peels of this plant have been well documented for their therapeutic value in Asia and Africa. It has also been previously reported for numerous biological applications such as antimicrobial, antioxidant, itching, psoriasis and anti-diarrheal activities. Moreover, M. acuminata peels have been well known for its anti-healing and antiseptic properties and most commonly used for healing wounds and heat burns in South Asian and African traditional medicines.<br><br>AIM OF THE STUDY: To evaluate the QS-mediated antibiofilm and antivirulence potential of M. acuminata, and its bioactive metabolites 5-Hydroxymethylfurfural (5HMF) against Pseudomonas aeruginosa.<br><br>MATERIALS AND METHODS: The M. acuminata peel methanol extract (MAM) was evaluated for its antibiofilm potential against P. aeruginosa with increasing concentration. Besides, biofilm related phenomenon's such as total biofilm proteins, microcolony formation exopolysaccharides (EPS) and cell surface hydrophobicity (CSH) productions were also examined to support the antibiofilm potential of MAM. Further, MAM was evaluated for its antivirulence efficacy against P. aeruginosa by assessing the protease, LasA protease, LasB elastase, pyocyanin, alginate and rhamnolipid productions at 400 μg ml-1 concentration. Transcriptional analysis of QS regulated virulence genes expression level was also done by real-time PCR analysis. Then, the MAM was subjected to column chromatography for further fractions and the bioactive compounds present in MAM were identified by gas chromatograph-mass spectrometry analysis. Further, the major compounds such as 5-hydroxymethylfurfural, vaccenic acid and pentanoic acid identified from active fraction of MAM were evaluated for their antibiofilm and antivirulence potential against P. aeruginosa.<br><br>RESULTS: MAM significantly inhibited the biofilm formation in P. aeruginosa at 400 μg ml-1 concentration which also inhibited the production of biofilm proteins, biofilm adherence, EPS and CSH productions to the level of 79%, 82% and 77% respectively. Further, the antivirulence potential was confirmed through numerous virulence inhibition assays. The MAM at 400 μg ml-1 concentration inhibited the QS-mediated virulence production such as protease, LasA protease, LasB elastase, pyocyanin, alginate and rhamnolipid productions to the level of 77%, 75%, 68%, 80%, 78% and 69% respectively. Moreover, the results of qPCR analysis confirmed the downregulation of QS regulated virulence genes expression upon treatment with MAM. The chromatographic analysis revealed the presence of 5-Hydroxymethylfurfural (5HMF), vaccenic acid and pentanoic acid in MAM and the potential bioactive compounds with antibiofilm and antivirulence was identified as 5-hydroxymethylfurfural, without exerting any growth inhibition in P. aeruginosa.<br><br>CONCLUSION: This study investigated the ideal antibiofilm and antivirulence potential of MAM and its bioactive compound 5HMF, and confirms the ethnopharmacological value of these peels against P. aeruginosa infections.},
}
@article {pmid31532581,
year = {2019},
author = {She, P and Wang, Y and Liu, Y and Tan, F and Chen, L and Luo, Z and Wu, Y},
title = {Effects of exogenous glucose on Pseudomonas aeruginosa biofilm formation and antibiotic resistance.},
journal = {MicrobiologyOpen},
volume = {8},
number = {12},
pages = {e933},
pmid = {31532581},
issn = {2045-8827},
support = {20150309//The New Xiangya Talent Project of The Third Xiangya Hospital of Central South University/ ; },
abstract = {Pseudomonas aeruginosa is commonly found in nosocomial and life-threatening infections in patients. Biofilms formed by P. aeruginosa exhibit much greater resistance to antibiotics than the planktonic form of the bacteria. Few groups have studied the effects of glucose, a major carbon source, and metabolite, on P. aeruginosa biofilm formation and on its metabolic pathways. In this study, we investigated the effect of glucose on the biofilm formation ability of P. aeruginosa and carried out a metabolomic analysis to identify whether glucose alters the metabolic activity of P. aeruginosa in biofilms. We found that glucose efficiently promoted P. aeruginosa biofilm formation by upregulating the expression of the extracellular polysaccharide-related gene pslA. Treatment with glucose caused an increase in 7 metabolites (including 3-hydroxypropionic acid, glucose-6-phosphate, and 2,3-dimethylsuccinic acid) and a decrease in 18 metabolites (including myo-inositol, glutamine, and methoxamedrine) in the biofilm. In addition, there was a synergistic effect between glucose and horse serum on biofilm formation when the two were added in combination, which also increased the resistance of biofilm to levofloxacin therapy. Thus, our work sheds light on the underlying mechanisms by which glucose may enhance biofilm formation and identifies novel targets for developing strategies to counteract biofilm formation.},
}
@article {pmid31532251,
year = {2019},
author = {Wang, H and Palmer, J and Flint, S},
title = {Function of pYV Plasmid on Biofilm Formation of Yersinia enterocolitica ERL032123 in the Presence of Ca2.},
journal = {Journal of food protection},
volume = {82},
number = {10},
pages = {1683-1687},
doi = {10.4315/0362-028X.JFP-19-018},
pmid = {31532251},
issn = {1944-9097},
abstract = {The effect of the virulence plasmid pYV and calcium ions on biofilm of Yersinia enterocolitica biofilm formation was determined using a microtiter plate assay. Loss of the pYV plasmid prevented biofilm formation and the presence of Ca2+ enhanced biofilm formation in cultures containing the pYV plasmid. Scanning electron microscopy supported the result from the microtiter plate assay showing that in the presence of Ca2+, the wild-type Y. enterocolitica strain formed a strong biofilm on a polycarbonate surface. The results implied that Ca2+ promotes Y. enterocolitica biofilm formation through the function of the pYV plasmid.},
}
@article {pmid31531452,
year = {2019},
author = {Baumeister, TUH and Staudinger, M and Wirgenings, M and Pohnert, G},
title = {Halogenated anilines as novel natural products from a marine biofilm forming microalga.},
journal = {Chemical communications (Cambridge, England)},
volume = {55},
number = {79},
pages = {11948-11951},
doi = {10.1039/c9cc05992j},
pmid = {31531452},
issn = {1364-548X},
mesh = {Aniline Compounds/*chemistry ; *Biofilms ; Biological Products/*chemistry ; Biosynthetic Pathways ; Halogenation ; Halogens/*chemistry ; Kinetics ; Microalgae/*chemistry ; },
abstract = {The toxic halogenated anilines 2,4,6-tribromoaniline, 2,4,6-trichloroaniline and their dibromochloro and bromodichloro derivatives were considered as compounds of exclusive synthetic origin. Labeling studies and kinetic experiments confirmed that these substances are also biosynthesized by a marine biofilm forming microalga. They represent a novel class of halogenated natural products.},
}
@article {pmid31531409,
year = {2019},
author = {Hwang, G and Paula, AJ and Hunter, EE and Liu, Y and Babeer, A and Karabucak, B and Stebe, K and Kumar, V and Steager, E and Koo, H},
title = {Catalytic antimicrobial robots for biofilm eradication.},
journal = {Science robotics},
volume = {4},
number = {29},
pages = {},
doi = {10.1126/scirobotics.aaw2388},
pmid = {31531409},
issn = {2470-9476},
support = {R01 DE018023/DE/NIDCR NIH HHS/United States ; R01 DE025848/DE/NIDCR NIH HHS/United States ; },
abstract = {Magnetically driven robots can perform complex functions in biological settings with minimal destruction. However, robots designed to damage deleterious biostructures could also have important impact. In particular, there is an urgent need for new strategies to eradicate bacterial biofilms as we approach a post-antibiotic era. Biofilms are intractable and firmly attached structures ubiquitously associated with drug-resistant infections and destruction of surfaces. Existing treatments are inadequate to both kill and remove bacteria leading to reinfection. Here we design catalytic antimicrobial robots (CARs) that precisely and controllably kill, degrade and remove biofilms with remarkable efficiency. CARs exploit iron oxide nanoparticles (NPs) with dual catalytic-magnetic functionality that (i) generate bactericidal free radicals, (ii) breakdown the biofilm exopolysaccharide (EPS) matrix, and (iii) remove the fragmented biofilm debris via magnetic field driven robotic assemblies. We develop two distinct CAR platforms. The first platform, the biohybrid CAR, is formed from NPs and biofilm degradation products. After catalytic bacterial killing and EPS disruption, magnetic field gradients assemble NPs and the biodegraded products into a plow-like superstructure. When driven with an external magnetic field, the biohybrid CAR completely removes biomass in a controlled manner, preventing biofilm regrowth. Biohybrid CARs can be swept over broad swathes of surface or can be moved over well-defined paths for localized removal with microscale precision. The second platform, the 3D molded CAR, is a polymeric soft robot with embedded catalytic-magnetic NPs, formed in a customized 3D printed mold to perform specific tasks in enclosed domains. Vane-shaped CARs remove biofilms from curved walls of cylindrical tubes, and helicoid-shaped CARs drill through biofilm clogs, while simultaneously killing bacteria. In addition, we demonstrate applications of CARs to target highly confined anatomical surfaces in the interior of human teeth. These 'kill-degrade-and-remove' CARs systems could have significant impact in fighting persistent biofilm-infections and in mitigating biofouling of medical devices and diverse surfaces.},
}
@article {pmid31531109,
year = {2019},
author = {Veloz, JJ and Alvear, M and Salazar, LA},
title = {Evaluation of Alternative Methods to Assess the Biological Properties of Propolis on Metabolic Activity and Biofilm Formation in Streptococcus mutans.},
journal = {Evidence-based complementary and alternative medicine : eCAM},
volume = {2019},
number = {},
pages = {1524195},
doi = {10.1155/2019/1524195},
pmid = {31531109},
issn = {1741-427X},
abstract = {Several biological activities have been reported for the Chilean propolis, among their antimicrobial and antibiofilm properties, due to its high polyphenol content. In this study, we evaluate alternative methods to assess the effect of Chilean propolis on biofilm formation and metabolic activity of Streptococcus mutans (S. mutans), a major cariogenic agent in oral cavity. Biofilm formation was studied by using crystal violet and by confocal microscopy. The metabolic activity of biofilm was evaluated by MTT and by flow cytometry analysis. The results show that propolis reduces biofilm formation and biofilm metabolic activity in S. mutans. When the variability of the methods to measure biofilm formation was compared, the coefficient of variation (CV) fluctuated between 12.8 and 23.1% when using crystal violet methodology. On the other hand, the CV ranged between 2.2 and 3.3% with confocal microscopy analysis. The CV for biofilm's metabolic activity measured by MTT methodology ranged between 5.0 and 11.6%, in comparison with 1.9 to 3.2% when flow cytometry analysis was used. Besides, it is possible to conclude that the methods based on colored compounds presented lower precision to study the effect of propolis on biofilm properties. Therefore, we recommend the use of flow cytometry and confocal microscopy in S. mutans biofilm analysis.},
}
@article {pmid31530887,
year = {2019},
author = {Marbach, H and Mayer, K and Vogl, C and Lee, JYH and Monk, IR and Sordelli, DO and Buzzola, FR and Ehling-Schulz, M and Grunert, T},
title = {Within-host evolution of bovine Staphylococcus aureus selects for a SigB-deficient pathotype characterized by reduced virulence but enhanced proteolytic activity and biofilm formation.},
journal = {Scientific reports},
volume = {9},
number = {1},
pages = {13479},
doi = {10.1038/s41598-019-49981-6},
pmid = {31530887},
issn = {2045-2322},
support = {FWF-P29304-B22//Austrian Science Fund (Fonds zur F&amp;#x00F6;rderung der Wissenschaftlichen Forschung)/ ; PP14311265//Veterin&amp;#x00E4;rmedizinische Universit&amp;#x00E4;t Wien (University of Veterinary Medicine, Vienna)/ ; },
abstract = {Staphylococcus aureus is a major cause of bovine mastitis, commonly leading to long-lasting, persistent and recurrent infections. Thereby, S. aureus constantly refines and permanently adapts to the bovine udder environment. In this work, we followed S. aureus within-host adaptation over the course of three months in a naturally infected dairy cattle with chronic, subclinical mastitis. Whole genome sequence analysis revealed a complete replacement of the initial predominant variant by another isogenic variant. We report for the first time within-host evolution towards a sigma factor SigB-deficient pathotype in S. aureus bovine mastitis, associated with a single nucleotide polymorphism in rsbU (G368A → G122D), a contributor to SigB-functionality. The emerged SigB-deficient pathotype exhibits a substantial shift to new phenotypic traits comprising strong proteolytic activity and poly-N-acetylglucosamine (PNAG)-based biofilm production. This possibly unlocks new nutritional resources and promotes immune evasion, presumably facilitating extracellular persistence within the host. Moreover, we observed an adaptation towards attenuated virulence using a mouse infection model. This study extends the role of sigma factor SigB in S. aureus pathogenesis, so far described to be required for intracellular persistence during chronic infections. Our findings suggest that S. aureus SigB-deficiency is an alternative mechanism for persistence and underpin the clinical relevance of staphylococcal SigB-deficient variants which are consistently isolated during human chronic infections.},
}
@article {pmid31529027,
year = {2019},
author = {Bjarnsholt, T and Jensen, PØ and Alhede, M},
title = {Revival of Krebs-Ringer balanced salt solution for the investigation of polymorphonuclear leukocytes and Pseudomonas aeruginosa biofilm interaction.},
journal = {Pathogens and disease},
volume = {77},
number = {5},
pages = {},
doi = {10.1093/femspd/ftz052},
pmid = {31529027},
issn = {2049-632X},
abstract = {To study the interaction between aggregating bacteria and polymorphonuclear leukocytes (PMNs) in vitro, the chosen medium must favor both the isolated PMNs and the bacteria. To investigate the best-suited medium for the in vitro survival of isolated unactivated human PMNs, we compared three different mammalian cell media: Krebs-Ringer balanced salt solution (BSS), Hanks' BSS (HBSS) and Roswell Park Memorial Institute (RPMI) 1640. The death of PMNs was estimated by the release of lactate dehydrogenase activity. Furthermore, two types of serum, human (HS) and fetal bovine (FBS), were compared at different concentrations (0%, 2%, 5%, 10%) and at three different time points (2, 4, 20 h). We show that Krebs-Ringer BSS prolonged the survival of PMNs compared to HBSS and RPMI 1640 and that the addition of 10% FBS significantly enhanced the long-term survival (20 h) compared to HS. Furthermore, we observed aggregation of Pseudomonas aeruginosa when grown in the presence of either a mixture of histones, histone H3, arginine or lysine. In this study, we show that the use of Krebs-Ringer BSS is highly relevant for the study of the interaction of bacteria and PMNs in relation to novel treatment strategies of biofilm infections due to the reproduction of bacterial aggregation as seen in chronic bacterial infections.},
}
@article {pmid31528252,
year = {2019},
author = {Song, YG and Lee, SH},
title = {Efficacy of newly developed denture cleaning device on physical properties of denture material and Candida biofilm.},
journal = {Journal of dental sciences},
volume = {14},
number = {3},
pages = {248-254},
doi = {10.1016/j.jds.2019.01.011},
pmid = {31528252},
issn = {2213-8862},
abstract = {Background/purpose: Electrolyzed water has antimicrobial activity against oral microbes. The purpose of this study was to investigate the effects of a denture cleaning device that uses electrolyzed water on Candida biofilm on denture base-material and the physical properties of the denture material.<br><br>Materials and methods: Denture base-resin disks were prepared with Polymethyl methacrylate. After the formation of Candida albicans biofilm on the resin disks, the antimicrobial activity of the denture cleaning device and the chemical cleanser against C. albicans biofilm was compared. The resin disks were also treated with the cleaning device and the chemical cleanser for 150 days, and the physical properties were analyzed by an atomic force microscope, Vickers hardness tester, and colorimeter.<br><br>Results: The denture cleaning device and the chemical cleanser reduced the levels of C. albicans biofilm on the denture resin. Upon immersing of the resin disks for 150 days, the electrolyzed water of the denture cleaning device did not significantly change the surface roughness of the specimens, but significantly reduced its Vickers hardness compared to the initial value. The color changes of the resin disk were 0.477 ± 0.076, 0.612 ± 0.095 and 0.562 ± 0.096 after treating with tap water, the chemical cleanser, and the denture cleaning device, respectively.<br><br>Conclusion: The denture cleaning device may be suitable for use by the elderly to clean dentures without side effects caused by the misuse of chemical cleanser.},
}
@article {pmid31528123,
year = {2019},
author = {Thieme, L and Hartung, A and Tramm, K and Klinger-Strobel, M and Jandt, KD and Makarewicz, O and Pletz, MW},
title = {MBEC Versus MBIC: the Lack of Differentiation between Biofilm Reducing and Inhibitory Effects as a Current Problem in Biofilm Methodology.},
journal = {Biological procedures online},
volume = {21},
number = {},
pages = {18},
doi = {10.1186/s12575-019-0106-0},
pmid = {31528123},
issn = {1480-9222},
abstract = {Background: Biofilms are communities of aggregated, matrix-embedded microbial cells showing a high tolerance to an in principle adequate antibiotic therapy, often resulting in treatment failure. A major challenge in the management of biofilm-associated infections is the development of adequate, standardized biofilm susceptibility testing assays that are clinically meaningful, i.e. that their results correlate with treatment outcome. Different biofilm susceptibility endpoint parameters like the minimal biofilm eradication concentration (MBEC) or the minimal biofilm inhibitory concentration (MBIC) have been suggested as a guide for treatment of biofilm-associated infections, however with inconsistent perception and use among biofilm researchers, leading to confusion and contradictions among different anti-biofilm component studies and clinical trials.<br><br>Findings: Evaluation of anti-biofilm effects is mostly based on the untreated reference growth control biofilm measured at the same endpoint as the treated biofilm, neglecting the possible change of the untreated reference biofilm from the time point of pre-antimicrobial exposure to the measured endpoint. In this commentary, we point out the importance of individual quantification of mature, established biofilms before antimicrobial treatment for each biofilm model in order to draw conclusions on the measured biofilm effect size, i.e. biofilm reducing (MBEC) or biofilm inhibitory (MBIC) effects.<br><br>Conclusion: The assessment of pre-treatment biofilms contributes to a standardized use of biofilm susceptibility endpoint parameters, which is urgently needed to improve the clinical validity of future anti-biofilm assays.},
}
@article {pmid31527127,
year = {2019},
author = {Sultan, AR and Hoppenbrouwers, T and Lemmens-den Toom, NA and Snijders, SV and van Neck, JW and Verbon, A and de Maat, MPM and van Wamel, WJB},
title = {During the Early Stages of Staphylococcus aureus Biofilm Formation, Induced Neutrophil Extracellular Traps Are Degraded by Autologous Thermonuclease.},
journal = {Infection and immunity},
volume = {87},
number = {12},
pages = {},
pmid = {31527127},
issn = {1098-5522},
abstract = {Staphylococcus aureus extracellular DNA (eDNA) plays a crucial role in the structural stability of biofilms during bacterial colonization; on the contrary, host immune responses can be induced by bacterial eDNA. Previously, we observed production of S. aureus thermonuclease during the early stages of biofilm formation in a mammalian cell culture medium. Using a fluorescence resonance energy transfer (FRET)-based assay, we detected thermonuclease activity of S. aureus biofilms grown in Iscove's modified Dulbecco's medium (IMDM) earlier than that of widely studied biofilms grown in tryptic soy broth (TSB). The thermonuclease found was Nuc1, confirmed by mass spectrometry and competitive Luminex assay. These results indicate that biofilm development in IMDM may not rely on eDNA for structural stability. A bacterial viability assay in combination with wheat germ agglutinin (WGA) staining confirmed the accumulation of dead cells and eDNA in biofilms grown in TSB. However, in biofilms grown in IMDM, minimal amounts of eDNA were found; instead, polysaccharide intercellular adhesin (PIA) was detected. To investigate if this early production of thermonuclease plays a role in immune modulation by biofilm, we studied the effect of thermonuclease on human neutrophil extracellular trap (NET) formation using a nuc knockout and complemented strain. We confirmed that thermonuclease produced by early-stage biofilms grown in IMDM degraded biofilm-induced NETs. Additionally, neither the presence of biofilms nor thermonuclease stimulated an increase in reactive oxygen species (ROS) production by neutrophils. Our findings indicated that S. aureus, during the early stages of biofilm formation, actively evades the host immune responses by producing thermonuclease.},
}
@article {pmid31525949,
year = {2019},
author = {Wang, ZH and Liu, JM and Li, CY and Wang, D and Lv, H and Lv, SW and Zhao, N and Ma, H and Wang, S},
title = {Bacterial Biofilm Bioinspired Persistent Luminescence Nanoparticles with Gut-Oriented Drug Delivery for Colorectal Cancer Imaging and Chemotherapy.},
journal = {ACS applied materials &amp; interfaces},
volume = {11},
number = {40},
pages = {36409-36419},
doi = {10.1021/acsami.9b12853},
pmid = {31525949},
issn = {1944-8252},
abstract = {Colorectal cancer (CRC) is now one of the leading causes of cancer incidence and mortality. Although nanomaterial-based drug delivery has been used for the treatment of colorectal cancer, inferior targeting ability of existing nanocarriers leads to inefficient treatment and side effects. Moreover, the majority of intravenously administered nanomaterials aggregate into the reticuloendothelial system, leaving a certain hidden risk to human health. All those problems gave great demands for further construction of well-performed and biocompatible nanomaterials for in vivo theranostics. In the present work, from a biomimetic point of view, Lactobacillus reuteri biofilm (LRM) was coated on the surface of trackable zinc gallogermanate (ZGGO) near-infrared persistent luminescence mesoporous silica to create the bacteria bioinspired nanoparticles (ZGGO@SiO2@LRM), which hold the inherent capability of withstanding the digestion of gastric acid and targeted release 5-FU to colorectum. Through the background-free persistent luminescence bioimaging of ZGGO, the coating of LRM facilitated the localization of ZGGO@SiO2@LRM to the tumor area of colorectum for more than 24 h after intragastric administration. Furthermore, ZGGO@SiO2@LRM hardly entered the blood, which avoided possible damage to immune organs such as the liver and spleen. In vivo chemotherapy experiment demonstrated the number of tumors per mouse in ZGGO@SiO2@LRM group decreased by one-half compared with the 5-FU group (P < 0.001). To sum up, this LRM bioinspired nanoparticles could tolerate the digestion of gastric acid, avoid aggregation by the immune system, favor gut-oriented drug delivery, and targeted release oral 5-FU into colorectum for more than 24 h, which may give new application prospects for targeted delivery of oral drugs into the colorectum.},
}
@article {pmid31524581,
year = {2019},
author = {Brown, JL and Johnston, W and Delaney, C and Short, B and Butcher, MC and Young, T and Butcher, J and Riggio, M and Culshaw, S and Ramage, G},
title = {Polymicrobial oral biofilm models: simplifying the complex.},
journal = {Journal of medical microbiology},
volume = {68},
number = {11},
pages = {1573-1584},
doi = {10.1099/jmm.0.001063},
pmid = {31524581},
issn = {1473-5644},
mesh = {Animals ; Bacteria/classification/genetics/*isolation &amp; purification ; Bacterial Physiological Phenomena ; *Biofilms ; Humans ; Mouth/*microbiology ; },
abstract = {Over the past century, numerous studies have used oral biofilm models to investigate growth kinetics, biofilm formation, structure and composition, antimicrobial susceptibility and host-pathogen interactions. In vivo animal models provide useful models of some oral diseases; however, these are expensive and carry vast ethical implications. Oral biofilms grown or maintained in vitro offer a useful platform for certain studies and have the advantages of being inexpensive to establish and easy to reproduce and manipulate. In addition, a wide range of variables can be monitored and adjusted to mimic the dynamic environmental changes at different sites in the oral cavity, such as pH, temperature, salivary and gingival crevicular fluid flow rates, or microbial composition. This review provides a detailed insight for early-career oral science researchers into how the biofilm models used in oral research have progressed and improved over the years, their advantages and disadvantages, and how such systems have contributed to our current understanding of oral disease pathogenesis and aetiology.},
}
@article {pmid31523511,
year = {2019},
author = {Pelyuntha, W and Chaiyasut, C and Kantachote, D and Sirilun, S},
title = {Cell-free supernatants from cultures of lactic acid bacteria isolated from fermented grape as biocontrol against Salmonella Typhi and Salmonella Typhimurium virulence via autoinducer-2 and biofilm interference.},
journal = {PeerJ},
volume = {7},
number = {},
pages = {e7555},
doi = {10.7717/peerj.7555},
pmid = {31523511},
issn = {2167-8359},
abstract = {Background: Salmonella Typhi and Salmonella Typhimurium are the causative pathogens of salmonellosis, and they are mostly found in animal source foods (ASF). The inappropriate use of antibiotics enhances the possibility for the emergence of antibiotic resistance in pathogens and antibiotic residue in ASF. One promising alternative to antibiotics in animal farming is the use of lactic acid bacteria (LAB).<br><br>Methods: The present study was carried out the cells and/or the cell-free culture supernatants (CFCS) from beneficial LAB against S. Typhi and S. Typhimurium. The antibacterial mechanisms of LAB-CFCS as biocontrol agents against both Salmonella serovars were investigated through the analysis of anti-salmonella growth activity, biofilm inhibition and quorum quenching activity.<br><br>Results: Among 146 LAB strains isolated from 110 fermented food samples, the 2 strong inhibitory effect strains (WM33 and WM36) from fermented grapes against both Salmonella serovars were selected. Out of the selected strains, WM36 was the most effective inhibitor, which indicated S. Typhi by showing 95.68% biofilm inhibition at 20% biofilm inhibition concentration (BIC) and reduced 99.84% of AI-2 signaling interference. The WM33 was the best to control S. Typhimurium by producing 66.46% biofilm inhibition at only 15% BIC and 99.99% AI-2 signaling a reduction. The 16S rDNA was amplified by a polymerase chain reaction (PCR). The selected isolates were identified as Weissella viridescens WM33 and Weissella confusa WM36 based on nucleotide homology and phylogenetic analysis.<br><br>Conclusion: The metabolic extracts from Weissella spp. inhibit Salmonella serovars with the potential to be used as biocontrol agents to improve microbiological safety in the production of ASF.},
}
@article {pmid31523409,
year = {2019},
author = {Saidi, N and Owlia, P and Marashi, SMA and Saderi, H},
title = {Inhibitory effect of probiotic yeast Saccharomyces cerevisiae on biofilm formation and expression of α-hemolysin and enterotoxin A genes of Staphylococcus aureus.},
journal = {Iranian journal of microbiology},
volume = {11},
number = {3},
pages = {246-254},
pmid = {31523409},
issn = {2008-3289},
abstract = {Background and Objectives: Staphylococcus aureus, as an opportunistic pathogen, is the cause of a variety of diseases from mild skin infections to severe invasive infections and food poisoning. Increasing antibiotic resistance in S. aureus isolates has become a major threat to public health. The use of compounds produced by probiotics can be a solution to this problem. Thus, the purpose of this study was to investigate the effect of Saccharomyces cerevisiae on some virulence factors (biofilm, α-hemolysin, and enterotoxin A) of S. aureus.<br><br>Materials and Methods: Supernatant and lysate extracts were prepared from S. cerevisiae S3 culture. Sub-MIC concentrations of both extracts were separately applied to S. aureus ATCC 29213 (methicillin-sensitive S. aureus; MSSA) and S. aureus ATCC 33591 (methicillin-resistant S. aureus; MRSA) strains. Biofilm formation of these strains was measured by microtiter plate assay and expression level of α-hemolysin and enterotoxin A genes (hla and sea, respectively) using real-time PCR technique.<br><br>Results: The supernatant extract has reduced both biofilm formation and expression of sea and hla genes, while lysate extract had only anti-biofilm effects. The MRSA strain showed more susceptibility to yeast extracts than MSSA strain in all tests.<br><br>Conclusion: The present study exhibited favorable antagonistic effects of S. cerevisiae S3, as a probiotic yeast, on MSSA and MRSA strains. Based on the findings of this study, the compounds produced by this yeast can be used to control S. aureus infections; however, further similar studies should be conducted to confirm the findings of the present study.},
}
@article {pmid31523169,
year = {2019},
author = {Liu, J and Cai, M and Yan, H and Fu, J and Wu, G and Zhao, Z and Zhao, Y and Wang, Y and Sun, Y and You, Y and Lin, L and Huang, J and Huang, R and Zeng, J},
title = {Yunnan Baiyao reduces hospital-acquired pressure ulcers via suppressing virulence gene expression and biofilm formation of Staphylococcus aureus.},
journal = {International journal of medical sciences},
volume = {16},
number = {8},
pages = {1078-1088},
doi = {10.7150/ijms.33723},
pmid = {31523169},
issn = {1449-1907},
abstract = {Yunnan Baiyao (YB) as a kind of famous Chinese herbal medicine, possessed hemostatic, invigorating the circulation of blood, and anti-inflammatory effects. Identifying strategies to protect patients at risk for hospital-acquired pressure ulcers (HAPU) is essential. Herein, our results showed that YB treatment can effectively reduce the acne wound area and improve efficacy in a comparative study of 60 cases HAPU patients with S. aureus positive of acne wound pathogens. Furthermore, YB inhibited HIa expression and suppressed accessory gene regulator (agr) system controlled by regulatory RNA II and RNA III molecule using pALC1740, pALC1742 and pALC1743 S. aureus strain linked to gfpuvr reporter gene. Moreover, YB downregulated cao mRNA expression and inhibited coagulase activity by RT-PCR, slide and tube coagulase test. Additionally, YB downregulated seb, sec, sed, and tsst-1 mRNA expression to suppress enterotoxin and tsst-1 secretion and adhesion function related genes sarA, icaA, and cidA mRNA expression. Taken together, the data suggest that YB may reduce HAPU via suppressing virulence gene expression and biofilm formation of S. aureus.},
}
@article {pmid31521779,
year = {2019},
author = {Alfa, MJ and Singh, H},
title = {Impact of wet storage and other factors on biofilm formation and contamination of patient-ready endoscopes: a narrative review.},
journal = {Gastrointestinal endoscopy},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.gie.2019.08.043},
pmid = {31521779},
issn = {1097-6779},
abstract = {The 2019 U.S. Food and Drug Administration report indicates that the clinical studies undertaken by the 3 main GI endoscope manufacturers demonstrate 5.4% of patient-ready duodenoscopes remain culture positive for high-concern organisms. The root causes of this persistent contamination are poorly understood. The objectives of this review include summarizing (1) the impact of inadequate manual cleaning and inadequate drying during storage on the formation of build-up biofilm in endoscope channels, (2) the impact of defoaming agents used during patient procedures on drying efficacy, (3) the data showing the importance of build-up biofilm on persistent microbial survival, and (4) the potential impact of implementation of a quality systems approach in GI endoscopy reprocessing.},
}
@article {pmid31521732,
year = {2019},
author = {Horiuchi, A and Kokubu, E and Warita, T and Ishihara, K},
title = {Synergistic biofilm formation by Parvimonas micra and Fusobacterium nucleatum.},
journal = {Anaerobe},
volume = {},
number = {},
pages = {102100},
doi = {10.1016/j.anaerobe.2019.102100},
pmid = {31521732},
issn = {1095-8274},
abstract = {Parvimonas micra is frequently isolated from lesions of apical periodontitis and is a major disease-related pathogen. One of the main causes of apical periodontitis is extraradicular biofilm. In this study, we investigated polymicrobial biofilm formation by P. micra and species associated with apical periodontitis. The coaggregation activity of P. micra with partner strains was investigated by visual assays. Synergistic biofilm formation was evaluated by cocultures of P. micra and partner strains. Growth of planktonic cells was measured by evaluating the absorbance at OD660, and biofilm formation was examined by staining with crystal violet. The effects of soluble components on synergistic biofilm formation and planktonic cell growth were examined after coculture of P. micra and other strains separated with a 0.4-μm pore-size porous membrane. P. micra coaggregated with Fusobacterium nucleatum, Porphyromonas gingivalis, or Capnoctyophaga ochracea. P. micra showed no coaggregation with Staphylococcus aureus, S. epidermidis, or Prevotella intermedia. In mixed cultures, biofilm formation by P. micra and F. nucleatum was greater than that by P. micra and P. gingivalis or C. ochracea. In separated cocultures, planktonic cell growth of P. micra was enhanced by each of the three species. Biofilm formation by P. micra was enhanced by F. nucleatum or C. ochracea; however, no significant enhancement was observed with P. gingivalis. These data indicated that P. micra and F. nucleatum had synergistic effects in biofilm formation and that these effects may be important for colonization by these two species in apical periodontitis lesions.},
}
@article {pmid31520957,
year = {2019},
author = {Cheng, H and Cheng, D and Mao, J and Lu, T and Hong, PY},
title = {Identification and characterization of core sludge and biofilm microbiota in anaerobic membrane bioreactors.},
journal = {Environment international},
volume = {133},
number = {Pt A},
pages = {105165},
doi = {10.1016/j.envint.2019.105165},
pmid = {31520957},
issn = {1873-6750},
abstract = {An analysis of sludge (i.e., 63 samples) and biofilm (i.e., 79 samples) sampled from 13 anaerobic membrane bioreactors (AnMBR) was conducted. Predominant microbial community identification and multivariate analysis indicate that these reactors showed different microbial community structure, but these differences had no impact on the overall AnMBR performance. Instead, core microbial genera which occurred in ≥90% of sludge (20 genera) and biofilm (12 genera) samples could potentially account for the AnMBR performance. A further calculation on net growth rate (NGR) of core genera in sludge suggested distribution into two main groups (i.e., I: low relative abundance and NGR, II: high relative abundance or high NGR). Consistent positive correlations between bacterial genera were observed among those that exhibited either high relative abundance or high NGR. The anaerobic microbial consortium in both sludge and biofilm were largely affected by stochastic dispersal and migration processes (i.e., neutral assembly). However, Acinetobacter spp. and Methanobacterium spp. occurred consistently in higher frequency in the biofilm but in lower occurrence frequency in the AnMBR permeate. Findings from this study suggest first, specific core microorganisms exist in the sludge regardless of the operating conditions of the AnMBRs, and second, prevention of biofoulant layer on anaerobic membranes can be devised by minimizing attachment of microbes on surfaces in a non-selective manner.},
}
@article {pmid31520885,
year = {2019},
author = {Yuan, Z and Tao, B and He, Y and Mu, C and Liu, G and Zhang, J and Liao, Q and Liu, P and Cai, K},
title = {Remote eradication of biofilm on titanium implant via near-infrared light triggered photothermal/photodynamic therapy strategy.},
journal = {Biomaterials},
volume = {223},
number = {},
pages = {119479},
doi = {10.1016/j.biomaterials.2019.119479},
pmid = {31520885},
issn = {1878-5905},
abstract = {Biofilm formation is a main challenge in treatment of bone-implant-associated infections, resulting in tolerance to immune system and antibiotics. However, smart non-surgical or non-invasive treatment methods of combating established biofilm on an implant have been less reported. Herein, a therapeutic system consisting of mesoporous polydopamine nanoparticles (MPDA) to combat biofilm is reported for the first time. We develop a synergistic photothermal/photodynamic therapy (PTT/PDT) strategy aiming for biofilms eradication on titanium (Ti) implant, which is integrated with MPDA loading with photosensitizer Indocyanine Green (ICG) by π-π stacking. Specifically, MPDA is functionalized with RGD peptide to endow the modified Ti sample (Ti-M/I/RGD) with good cytocompatibility. More importantly, Ti-M/I/RGD implant remarkably kills Staphylococcus aureus (S. aureus) biofilm with an efficiency of 95.4% in vivo upon near infrared (NIR). After biofilm eradication, implant still displays great performance regarding osteogenesis and osseointegration. Overall, this study provides a PTT/PDT strtategy for the development of antibacterial Ti implants for potential orthpediac application.},
}
@article {pmid31519064,
year = {2019},
author = {Widiasih Widiyanto, T and Chen, X and Iwatani, S and Chibana, H and Kajiwara, S},
title = {Role of major facilitator superfamily transporter Qdr2p in biofilm formation by Candida glabrata.},
journal = {Mycoses},
volume = {62},
number = {12},
pages = {1154-1163},
doi = {10.1111/myc.13005},
pmid = {31519064},
issn = {1439-0507},
abstract = {Candida glabrata represents the second-most frequent cause of candidiasis infections of the mucosa, bloodstream and genito-urinary tract in immunocompromised individuals. The incidence of C glabrata infection has increased significantly in the last two decades, mainly due to this species' abilities to resist various antifungal drugs and to form biofilms. We focused on the relationship between biofilm formation and the product of QDR2, a C glabrata member of the major facilitator superfamily (MFS) gene family, given that fungal biofilm formation limits drug penetration and is associated with persistent infection. The fungal cells in biofilms were compared between a C glabrata ∆qdr2 mutant and its wild-type strain. Cells were analysed for metabolism activity and drug susceptibility (using tetrazolium assay), adhesion activity, growth assay and intracellular pH (using flow cytometry). Compared to the wild type, the C glabrata ∆qdr2 showed lower adhesion activity and higher fluconazole susceptibility when assessed as a biofilm. The mutant also showed decreased metabolic activity during biofilm formation. Furthermore, the mutant grew more slowly under neutral-basic pH conditions. The qdr2 deletion in C glabrata resulted in an impaired ability to maintain pH homeostasis, which led in turn to a reduction of cell growth and of adherence to an artificial matrix. These results suggested that the Qdr2p function is needed for proper biofilm formation and biofilm maintenance in C glabrata as well as biofilm drug resistance towards fluconazole. Qdr2p may play an important role in C glabrata's ability to form biofilms on implanted medical devices in human bodies.},
}
@article {pmid31518800,
year = {2019},
author = {Iannacone, F and Di Capua, F and Granata, F and Gargano, R and Pirozzi, F and Esposito, G},
title = {Effect of carbon-to-nitrogen ratio on simultaneous nitrification denitrification and phosphorus removal in a microaerobic moving bed biofilm reactor.},
journal = {Journal of environmental management},
volume = {250},
number = {},
pages = {109518},
doi = {10.1016/j.jenvman.2019.109518},
pmid = {31518800},
issn = {1095-8630},
mesh = {Biofilms ; Bioreactors ; Carbon ; *Denitrification ; *Nitrification ; Nitrogen ; Phosphorus ; Sewage ; Waste Disposal, Fluid ; Waste Water ; },
abstract = {In this study, long-term simultaneous nitrification denitrification (SND) and phosphorous removal were investigated in a continuous-flow microaerobic MBBR (mMBBR) operated at a dissolved oxygen (DO) concentration of 1.0 (±0.2) mg L-1. The mMBBR performance was evaluated at different feed carbon-to-nitrogen (C/N) ratios (2.7, 4.2 and 5.6) and HRTs (2 days and 1 day). Stable long-term mMBBR operation and chemical oxygen demand (COD), total inorganic nitrogen (TIN) and phosphorous (P-PO43-) removal efficiencies up to 100%, 68% and 72%, respectively, were observed at a feed C/N ratio of 4.2. Lower TIN removal efficiency and unstable performance were observed at feed C/N ratios of 2.7 and 5.6, respectively. HRT decrease from 2 days to 1 day resulted in transient NH4+ accumulation and higher NO2-/NO3- ratio in the effluent. Batch activity tests showed that biofilm cultivation at a feed C/N ratio of 4.2 resulted in the highest denitrifying activity (189 mg N gVSS-1 d-1), whereas the highest nitrifying activity (316 mg N gVSS-1 d-1) was observed after cultivation at a feed C/N ratio of 2.7. Thermodynamic modeling with Visual MINTEQ and stoichiometric evaluations revealed that P removal was mainly biological and can be attributed to the P-accumulating capacity of denitrifying bacteria.},
}
@article {pmid31518447,
year = {2019},
author = {Kettles, RA and Tschowri, N and Lyons, KJ and Sharma, P and Hengge, R and Webber, MA and Grainger, DC},
title = {The Escherichia coli MarA protein regulates the ycgZ-ymgABC operon to inhibit biofilm formation.},
journal = {Molecular microbiology},
volume = {112},
number = {5},
pages = {1609-1625},
pmid = {31518447},
issn = {1365-2958},
support = {BB/N014200/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/R012504/1 and its constituent project BBS/E/F/0/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; MIBTP/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; He1556/13-2//Deutsche Forschungsgemeinschaft/ ; AAMR DTP/WT_/Wellcome Trust/United Kingdom ; },
abstract = {The Escherichia coli marRAB operon is a paradigm for chromosomally encoded antibiotic resistance. The operon exerts its effect via an encoded transcription factor called MarA that modulates efflux pump and porin expression. In this work, we show that MarA is also a regulator of biofilm formation. Control is mediated by binding of MarA to the intergenic region upstream of the ycgZ-ymgABC operon. The operon, known to influence the formation of curli fibres and colanic acid, is usually expressed during periods of starvation. Hence, the ycgZ-ymgABC promoter is recognised by σ38 (RpoS)-associated RNA polymerase (RNAP). Surprisingly, MarA does not influence σ38 -dependent transcription. Instead, MarA drives transcription by the housekeeping σ70 -associated RNAP. The effects of MarA on ycgZ-ymgABC expression are coupled with biofilm formation by the rcsCDB phosphorelay system, with YcgZ, YmgA and YmgB forming a complex that directly interacts with the histidine kinase domain of RcsC.},
}
@article {pmid31516325,
year = {2019},
author = {Farrag, HA and Hosny, AEMS and Hawas, AM and Hagras, SAA and Helmy, OM},
title = {Potential efficacy of garlic lock therapy in combating biofilm and catheter-associated infections; experimental studies on an animal model with focus on toxicological aspects.},
journal = {Saudi pharmaceutical journal : SPJ : the official publication of the Saudi Pharmaceutical Society},
volume = {27},
number = {6},
pages = {830-840},
doi = {10.1016/j.jsps.2019.05.004},
pmid = {31516325},
issn = {1319-0164},
abstract = {Background: Life-threatening central venous catheter-related infections are primarily initiated by biofilm formation on the catheter surface. Antibiotic lock therapy is recommended for eradicating intraluminal biofilm. In the era of antibiotic resistance, antibiotics of natural origins provide an effective and cheap option for combating resistant strains. Garlic especially stole the spotlight because of its impressive antimicrobial effectiveness against such superbugs.<br><br>Aim: Is to estimate the potential use of fresh garlic extract (FGE) as a lock agent against multi-drug resistant (MDR) bacteria.<br><br>Methods: The agar well diffusion and broth microdilution techniques were employed to test the antimicrobial activities of FGE against five MDR strains; E. coli, Pseudomonas aeruginosa (P. aeruginosa), Klebsiella pneumoniae (K. pneumoniae), Serratia marscens (S. marscens) and Methicillin-resistant Staphylococcus aureus (MRSA). Then the protective and therapeutic efficiencies of FGE against bacterial biofilms were in-vitro evaluated; at concentrations of 100, 75, 50 and 25%; in tissue culture plate (TCP) and on the polyurethane (PU) sheets using the crystal violet (CV) assay and colony-forming unit (CFU), respectively. Scanning electron microscopy (SEM) was also used to confirm eradication of biofilms on PU sheets. Finally, systemic and deep tissue infections by P. aeruginosa and MRSA were induced in mice that were then treated by FGE at either 100 or 200 mg/kg for seven days. Where the antibacterial activity was assessed by tissue and blood culturing at the end of the treatment period. Biochemical, hematological and histological parameters were also investigated.<br><br>Results: FGE exhibited potent in-vitro and in-vivo antibacterial and antibiofilm activities against MDR strains. It not only didn't exhibit toxicological effects at the hematological and the histological levels but also provided protective effects as demonstrated by the significant drop in the biochemical parameters.<br><br>Conclusion: FGE has the potential to be used as a prophylactic and/or therapeutic lock agent against biofilm-associated infections caused by MDR bacteria.},
}
@article {pmid31515923,
year = {2019},
author = {Røder, HL and Liu, W and Sørensen, SJ and Madsen, JS and Burmølle, M},
title = {Interspecies interactions reduce selection for a biofilm optimized variant in a four-species biofilm model.},
journal = {Environmental microbiology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1462-2920.14802},
pmid = {31515923},
issn = {1462-2920},
abstract = {Multispecies biofilms are structured and spatially defined communities, where interspecies interactions impact assembly and functionality. Here we compared the spatial organization and growth of bacterial cells in differently composed biofilm communities over time to determine links between interspecies interactions and selection for biofilm phenotypes of individual species. An established model community consisting of Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans and Paenibacillus amylolyticus was used. It was found that interspecies interactions led to varying levels of selection for a new colony phenotype of X. retroflexus, depending on the presence/absence of other species. When M. oxydans was absent, X. retroflexus was not able to establish in the top layers of the biofilm, which led to selection for a hyper-matrix forming phenotype of X. retroflexus that successfully established in the biofilm top layers. No such phenotypic X. retroflexus variants were identified in the presence of M. oxydans. These findings indicate that interspecies interactions may lead to favourable localization of individual species in a multispecies biofilm and thereby reduce selection for competitive phenotypes. This article is protected by copyright. All rights reserved.},
}
@article {pmid31515192,
year = {2019},
author = {Kim, A and Jung, JH and Lee, YJ and Park, JW and Pyon, JK},
title = {Minimally invasive salvage of infected breast tissue expanders: A continuous closed irrigation technique based on surface biofilm disruption.},
journal = {Journal of plastic, reconstructive &amp; aesthetic surgery : JPRAS},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.bjps.2019.07.020},
pmid = {31515192},
issn = {1878-0539},
abstract = {BACKGROUND: Removal of the infected device has been the general treatment for device-associated infection in antibiotic failure. There have been anecdotal attempts to salvage infected medical devices by introducing a continuous closed irrigation system.<br><br>OBJECTIVE: This study examines whether continuous closed irrigation of an infected device is a successful alternative to removal in patients with recalcitrant device-associated infection.<br><br>METHODS: Patients who were diagnosed with recalcitrant periexpander infections during the course of expander-implant breast reconstruction from 2010 to 2018 were enrolled in a retrospective case-control study. Patients who failed antibiotics before 2017 underwent expander removal, but patients since 2017 underwent continuous closed irrigation of the infected expanders. Treatment details and clinical outcomes were compared. Rationale for expander irrigation was based on review of the current literature on biofilm research.<br><br>RESULTS: During the study period, 21 out of the 1176 patients were diagnosed with periexpander infection recalcitrant to antibiotic therapy. Among the 21 patients, 16 underwent expander removal and five underwent expander irrigation. Clinical outcomes were comparable in terms of resolution of infection signs. The irrigation group showed fewer patients who abandoned reconstruction after infection treatment (removal = 11/16, irrigation = 1/5). Literature review revealed that expander irrigation might have induced hydrodynamic disruption of the biofilm structure.<br><br>CONCLUSION: Expander irrigation was less invasive than removal and effective in suppressing severe recalcitrant periexpander infection. Continuous closed irrigation of infected expander devices may be a successful antibiofilm strategy in treating device-associated infections in select patients.},
}
@article {pmid31514534,
year = {2019},
author = {Braga, AS and Girotti, LD and de Melo Simas, LL and Pires, JG and Pelá, VT and Buzalaf, MAR and Magalhães, AC},
title = {Effect of commercial herbal toothpastes and mouth rinses on the prevention of enamel demineralization using a microcosm biofilm model.},
journal = {Biofouling},
volume = {35},
number = {7},
pages = {796-804},
doi = {10.1080/08927014.2019.1662897},
pmid = {31514534},
issn = {1029-2454},
abstract = {This work evaluated the effects of commercial toothpastes and mouth rinses containing natural/herbal agents on biofilm viability, extracellular polysaccharide (EPS) production and on enamel demineralization in vitro. Microcosm biofilm was produced on bovine enamel for 5 days and treated daily with: Orgânico natural® (toothpaste/mouth rinse), Boni Natural Menta &amp; Malaleuca® (toothpaste/mouth rinse), Propolis &amp; Myrrh® (toothpaste), Colgate Total 12 Clean Mint® (toothpaste, positive control), Malvatricin® Plus (mouth rinse), PerioGard® (mouth rinse, positive control) or PBS (negative control). Tom's Propolis &amp; Myrrh® and Colgate Total 12® toothpastes and Malvatricin® Plus and PerioGard® mouth rinses significantly reduced biofilm viability (p < 0.05). Only PerioGard® had significant effects on biofilm thickness and EPS. Despite the indication that Tom's Propolis &amp; Myrrh® significantly reduced lesion depth, only Colgate Total 12® significantly reduced mineral loss. Malvatricin® Plus significantly reduced mineral loss and lesion depth, as did PerioGard®. Some herbal products, Malvatricin® Plus and Tom's Propolis &amp; Myrrh®, showed anticaries effects.},
}
@article {pmid31514307,
year = {2019},
author = {Balázs, VL and Horváth, B and Kerekes, E and Ács, K and Kocsis, B and Varga, A and Böszörményi, A and Nagy, DU and Krisch, J and Széchenyi, A and Horváth, G},
title = {Anti-Haemophilus Activity of Selected Essential Oils Detected by TLC-Direct Bioautography and Biofilm Inhibition.},
journal = {Molecules (Basel, Switzerland)},
volume = {24},
number = {18},
pages = {},
pmid = {31514307},
issn = {1420-3049},
support = {NKFI 18 K 128217//NKFI (National Research, Development and Innovation Office)/ ; },
abstract = {Essential oils (EOs) are becoming increasingly popular in medical applications because of their antimicrobial effect. Direct bioautography (DB) combined with thin layer chromatography (TLC) is a screening method for the detection of antimicrobial compounds in plant extracts, for example, in EOs. Due to their lipophilic character, the common microbiological assays (etc. disk diffusion) could not provide reliable results. The aim of this study was the evaluation of antibacterial and anti-biofilm properties of the EO of cinnamon bark, clove, peppermint, thyme, and their main components against Haemophilus influenzae and H. parainfluenzae. Oil in water (O/W) type Pickering nano-emulsions stabilized with silica nanoparticles from each oil were prepared to increase their water-solubility. Samples with Tween80 surfactant and absolute ethanol were also used. Results showed that H. influenzae was more sensitive to the EOs than H. parainfluenzae (except for cinnamon bark oil). In thin layer chromatography-direct bioautography (TLC-DB) the ethanolic solutions of thyme oil presented the best activity against H. influenzae, while cinnamon oil was the most active against H. parainfluenzae. Pickering nano-emulsion of cinnamon oil inhibited the biofilm formation of H. parainfluenzae (76.35%) more efficiently than samples with Tween80 surfactant or absolute ethanol. In conclusion, Pickering nano-emulsion of EOs could inhibit the biofilm production effectively.},
}
@article {pmid31514119,
year = {2019},
author = {Zhang, Q and Yu, Z and Jin, S and Zhu, L and Liu, C and Zheng, H and Zhou, T and Liu, Y and Ruan, R},
title = {Lignocellulosic residue as bio-carrier for algal biofilm growth: Effects of carrier physicochemical proprieties and toxicity on algal biomass production and composition.},
journal = {Bioresource technology},
volume = {293},
number = {},
pages = {122091},
doi = {10.1016/j.biortech.2019.122091},
pmid = {31514119},
issn = {1873-2976},
mesh = {Biofilms ; Biomass ; *Chlorella vulgaris ; Lignin ; },
abstract = {Five types of lignocellulosic materials were applied as the bio-carriers for low-cost algal biofilm cultivation of three algal strains. The effects of bio-carrier physicochemical properties and toxicity on algal cells growth and attachment were investigated. Rougher