Biofilm最新文献

{"title":"Sub-MIC streptomycin and tetracycline enhanced Staphylococcus aureus Guangzhou-SAU749 biofilm formation, an in-depth study on transcriptomics","authors":"Junyan Liu ,&nbsp;Tengyi Huang ,&nbsp;Zhenbo Xu ,&nbsp;Yuzhu Mao ,&nbsp;Thanapop Soteyome ,&nbsp;Gongliang Liu ,&nbsp;Chunyun Qu ,&nbsp;Lei Yuan ,&nbsp;Qin Ma ,&nbsp;Fang Zhou ,&nbsp;Gamini Seneviratne","doi":"10.1016/j.bioflm.2023.100156","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100156","url":null,"abstract":"<div><p><em>Staphylococcus aureus</em> is a major human pathogen, a potential “Super-bug” and a typical biofilm forming bacteria. With usage of large amount of antibiotics, the residual antibiotics in clinical settings further complicate the colonization, pathogenesis and resistance of <em>S. aureus</em>. This study aimed at investigating the phenotypical and global gene expression changes on biofilm formation of a clinical <em>S. aureus</em> isolate treated under different types of antibiotics. Firstly, an isolate Guangzhou-SAU749 was selected from a large sale of previously identified <em>S. aureus</em> isolates, which exhibited weak biofilm formation in terms of biomass and viability. Secondly, 9 commonly prescribed antibiotics for <em>S. aureus</em> infections treatment, together with 10 concentrations ranging from 1/128 to 4 minimum inhibitory concentration (MIC) with 2-fold serial dilution, were used as different antibiotic stress conditions. Then, biofilm formation of <em>S. aureus</em> Guangzhou-SAU749 at different stages including 8 h, 16 h, 24 h, and 48 h, was tested by crystal violet and MTS assays. Thirdly, the whole genome of <em>S. aureus</em> Guangzhou-SAU749 was investigated by genome sequencing on PacBio platform. Fourthly, since enhancement of biofilm formation occurred when treated with 1/2 MIC tetracycline (TCY) and 1/4 MIC streptomycin (STR) since 5 h, the relevant biofilm samples were selected and subjected to RNA-seq and bioinformatics analysis. Last, expression of two component system (TCS) and biofilm associated genes in 4 h, 8 h, 16 h, 24 h, and 48 h sub-MIC TCY and STR treated biofilm samples were performed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Although most antibiotics lowered the biomass and cell viability of Guangzhou-SAU749 biofilm at concentrations higher than MIC, certain antibiotics including TCY and STR promoted biofilm formation at sub-MICs. Additionally, upon genome sequencing, RNA-seq and RT-qPCR on biofilm samples treated with sub-MIC of TCY and STR at key time points, genes <em>lytR</em>, <em>arlR</em>, <em>hssR</em>, <em>tagA</em>, <em>clfB</em>, <em>atlA</em> and <em>cidA</em> related to TCS and biofilm formation were identified to contribute to the enhanced biofilm formation, providing a theoretical basis for further controlling on <em>S. aureus</em> biofilm formation.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":6.8,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plasma activated water as a pre-treatment strategy in the context of biofilm-infected chronic wounds","authors":"Heema K.N. Vyas ,&nbsp;Binbin Xia ,&nbsp;David Alam ,&nbsp;Nicholas P. Gracie ,&nbsp;Joanna G. Rothwell ,&nbsp;Scott A. Rice ,&nbsp;Dee Carter ,&nbsp;Patrick J. Cullen ,&nbsp;Anne Mai-Prochnow","doi":"10.1016/j.bioflm.2023.100154","DOIUrl":"10.1016/j.bioflm.2023.100154","url":null,"abstract":"<div><p>Healing and treatment of chronic wounds are often complicated due to biofilm formation by pathogens. Here, the efficacy of plasma activated water (PAW) as a pre-treatment strategy has been investigated prior to the application of topical antiseptics polyhexamethylene biguanide, povidone iodine, and MediHoney, which are routinely used to treat chronic wounds. The efficacy of this treatment strategy was determined against biofilms of <em>Escherichia coli</em> formed on a plastic substratum and on a human keratinocyte monolayer substratum used as an <em>in vitro</em> biofilm-skin epithelial cell model. PAW pre-treatment greatly increased the killing efficacy of all the three antiseptics to eradicate the <em>E. coli</em> biofilms formed on the plastic and keratinocyte substrates. However, the efficacy of the combined PAW-antiseptic treatment and single treatments using PAW or antiseptic alone was lower for biofilms formed in the <em>in vitro</em> biofilm-skin epithelial cell model compared to the plastic substratum. Scavenging assays demonstrated that reactive species present within the PAW were largely responsible for its anti-biofilm activity. PAW treatment resulted in significant intracellular reactive oxygen and nitrogen species accumulation within the <em>E. coli</em> biofilms, while also rapidly acting on the microbial membrane leading to outer membrane permeabilisation and depolarisation. Together, these factors contribute to significant cell death, potentiating the antibacterial effect of the assessed antiseptics.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":6.8,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/e2/2a/main.PMC10522953.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41174187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Glycosyl hydrolase from Pseudomonas fluorescens inhibits the biofilm formation of Pseudomonads","authors":"Di Wang ,&nbsp;Syed Tatheer Alam Naqvi ,&nbsp;Fanglin Lei ,&nbsp;Zhenyu Zhang ,&nbsp;Haiying Yu ,&nbsp;Luyan Z. Ma","doi":"10.1016/j.bioflm.2023.100155","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100155","url":null,"abstract":"<div><p>Biofilms are complex microbial communities embedded in extracellular matrix. Pathogens within the biofilm become more resistant to the antibiotics than planktonic counterparts. Novel strategies are required to encounter biofilms. Exopolysaccharides are one of the major components of biofilm matrix and play a vital role in biofilm architecture. In previous studies, a glycosyl hydrolase, PslG_PA, from <em>Pseudomonas aeruginosa</em> was found to be able to inhibit biofilm formation by disintegrating exopolysaccharide in biofilms. Here, we investigate the potential spectrum of PslG homologous protein with anti-biofilm activity. One glycosyl hydrolase from <em>Pseudomonas fluorescens</em>, PslG_PF, exhibits anti-biofilm activities and the key catalytic residues of PslG_PF are conserved with those of PslG_PA. PslG_PF at concentrations as low as 50 nM efficiently inhibits the biofilm formation of <em>P. aeruginosa</em> and disassemble its preformed biofilm. Furthermore, PslG_PF exhibits anti-biofilm activity on a series of <em>Pseudomonads</em>, including <em>P. fluorescens, Pseudomonas stutzeri</em> and <em>Pseudomonas syringae</em> pv. <em>phaseolicola</em>. PslG_PF stays active under various temperatures. Our findings suggest that <em>P. fluorescens</em> glycosyl hydrolase PslG_PF has potential to be a broad spectrum inhibitor on biofilm formation of a wide range of <em>Pseudomonads</em>.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":6.8,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NaCl-induced modulation of species distribution in a mixed P. aeruginosa / S. aureus /B. cepacia biofilm","authors":"Jeanne Trognon ,&nbsp;Maya Rima ,&nbsp;Barbora Lajoie ,&nbsp;Christine Roques ,&nbsp;Fatima El Garah","doi":"10.1016/j.bioflm.2023.100153","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100153","url":null,"abstract":"<div><p><em>Pseudomonas aeruginosa</em>, <em>Staphylococcus aureus</em>, and <em>Burkholderia cepacia</em> are notorious pathogens known for their ability to form resilient biofilms, particularly within the lung environment of cystic fibrosis (CF) patients. The heightened concentration of NaCl, prevalent in the airway liquid of CF patients' lungs, has been identified as a factor that promotes the growth of osmotolerant bacteria like <em>S. aureus</em> and dampens host antibacterial defenses, thereby fostering favorable conditions for infections.</p><p>In this study, we aimed to investigate how increased NaCl concentrations impact the development of multi-species biofilms <em>in vitro</em>, using both laboratory strains and clinical isolates of <em>P. aeruginosa</em>, <em>S. aureus</em>, and B. cepacia co-cultures. Employing a low-nutrient culture medium that fosters biofilm growth of the selected species, we quantified biofilm formation through a combination of adherent CFU counts, qPCR analysis, and confocal microscopy observations.</p><p>Our findings reaffirmed the challenges faced by <em>S. aureus</em> in establishing growth within 1:1 mixed biofilms with <em>P. aeruginosa</em> when cultivated in a minimal medium. Intriguingly, at an elevated NaCl concentration of 145 mM, a symbiotic relationship emerged between <em>S. aureus</em> and <em>P. aeruginosa</em>, enabling their co-existence. Notably, this hyperosmotic environment also exerted an influence on the interplay of these two bacteria with <em>B. cepacia</em>. We demonstrated that elevated NaCl concentrations play a pivotal role in orchestrating the distribution of these three species within the biofilm matrix.</p><p>Furthermore, our study unveiled the beneficial impact of NaCl on the biofilm growth of clinically relevant mucoid <em>P. aeruginosa</em> strains, as well as two strains of methicillin-sensitive and methicillin-resistant <em>S. aureus</em>. This underscores the crucial role of the microenvironment during the colonization and infection processes. The results suggest that hyperosmotic conditions could hold the key to unlocking a deeper understanding of the genesis and behavior of CF multi-species biofilms.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":6.8,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bacillus subtilis NDmed, a model strain for biofilm genetic studies","authors":"Yasmine Dergham ,&nbsp;Dominique Le Coq ,&nbsp;Arnaud Bridier ,&nbsp;Pilar Sanchez-Vizuete ,&nbsp;Hadi Jbara ,&nbsp;Julien Deschamps ,&nbsp;Kassem Hamze ,&nbsp;Ken-ichi Yoshida ,&nbsp;Marie-Françoise Noirot-Gros ,&nbsp;Romain Briandet","doi":"10.1016/j.bioflm.2023.100152","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100152","url":null,"abstract":"<div><p>The <em>Bacillus subtilis</em> strain NDmed was isolated from an endoscope washer-disinfector in a medical environment. NDmed can form complex macrocolonies with highly wrinkled architectural structures on solid medium. In static liquid culture, it produces thick pellicles at the interface with air as well as remarkable highly protruding ‘‘beanstalk-like’’ submerged biofilm structures at the solid surface. Since these mucoid submerged structures are hyper-resistant to biocides, NDmed has the ability to protect pathogens embedded in mixed-species biofilms by sheltering them from the action of these agents. Additionally, this non-domesticated and highly biofilm forming strain has the propensity of being genetically manipulated. Due to all these properties, the NDmed strain becomes a valuable model for the study of <em>B</em>. <em>subtilis</em> biofilms. This review focuses on several studies performed with NDmed that have highlighted the sophisticated genetic dynamics at play during <em>B</em>. <em>subtilis</em> biofilm formation. Further studies in project using modern molecular tools of advanced technologies with this strain, will allow to deepen our knowledge on the emerging properties of multicellular bacterial life.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":6.8,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"α,α-disubstituted β-amino amides eliminate Staphylococcus aureus biofilms by membrane disruption and biomass removal","authors":"Dominik Ausbacher ,&nbsp;Lindsey A. Miller ,&nbsp;Darla M. Goeres ,&nbsp;Philip S. Stewart ,&nbsp;Morten B. Strøm ,&nbsp;Adyary Fallarero","doi":"10.1016/j.bioflm.2023.100151","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100151","url":null,"abstract":"<div><p>Bacterial biofilms account for up to 80% of all infections and complicate successful therapies due to their intrinsic tolerance to antibiotics. Biofilms also cause serious problems in the industrial sectors, for instance due to the deterioration of metals or microbial contamination of products. Efforts are put in finding novel strategies in both avoiding and fighting biofilms. Biofilm control is achieved by killing and/or removing biofilm or preventing transition to the biofilm lifestyle. Previous research reported on the anti-biofilm potency of α,α-disubstituted β-amino amides <strong>A1</strong>, <strong>A2</strong> and <strong>A3</strong>, which are small antimicrobial peptidomimetics with a molecular weight below 500 Da. In the current study it was investigated if these derivatives cause a fast disintegration of biofilm bacteria and removal of <em>Staphylococcus aureus</em> biofilms. One hour incubation of biofilms with all three derivatives resulted in reduced metabolic activity and membrane permeabilization in <em>S. aureus</em> (ATCC 25923) biofilms. Bactericidal properties of these derivatives were attributed to a direct effect on membranes of biofilm bacteria. The green fluorescence protein expressing <em>Staphylococcus aureus</em> strain AH2547 was cultivated in a CDC biofilm reactor and utilized for disinfectant efficacy testing of <strong>A3</strong>, following the single tube method (<em>American Society for Testing and Materials designation number E2871)</em>. <strong>A3</strong> at a concentration of 90 μM acted as fast as 100 μM chlorhexidine and was equally effective. Confocal laser scanning microscopy studies showed that chlorhexidine treatment lead to fluorescence fading indicating membrane permeabilization but did not cause biomass removal. In contrast, <strong>A3</strong> treatment caused a simultaneous biofilm fluorescence loss and biomass removal. These dual anti-biofilm properties make α,α-disubstituted β-amino amides promising scaffolds in finding new control strategies against recalcitrant biofilms.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":6.8,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Octanoic acid promotes clearance of antibiotic-tolerant cells and eradicates biofilms of Staphylococcus aureus isolated from recurrent bovine mastitis","authors":"Wen-Chun Lin ,&nbsp;Kai-Chen Hsu ,&nbsp;Ming-Feng You ,&nbsp;Kuo-Hua Lee ,&nbsp;Chau-Hwa Chi ,&nbsp;Jyh-Yih Chen","doi":"10.1016/j.bioflm.2023.100149","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100149","url":null,"abstract":"<div><p>Antibiotic therapy is the primary treatment for bovine mastitis, but the drawbacks of this strategy include poor cure rate and economic losses from the need to discard milk with antibiotic residues. Unfortunately, few other treatment options are currently available for mastitis. Failure of antibiotic treatments is often attributed to formation of bacterial biofilms and abscesses in the mammary gland tissue, which lead to chronic infections that are difficult to eradicate and drive recurrent disease. A major mastitis-causing pathogen (MCP) associated with biofilms in bovine mastitis is <em>Staphylococcus aureus</em>. In this study, we demonstrate that octanoic acid has broad-spectrum microbicidal activity against MCPs and effectively inhibits <em>S. aureus</em> biofilm formation in milk (&gt;50% inhibition at 3.13 mM). Octanoic acid effectively clears biofilms (95% eradication at 1<em>X</em> minimum bactericidal concentration, MBC) and infrequently induces <em>S. aureus</em> small colony variants (SCVs) that may cause recurrent mastitis. Additionally, octanoic acid rapidly kills persistent biofilm cells and cells with antibiotic tolerance (within 4 h). In contrast, antibiotics treated at &gt;100<em>X</em> MBC cannot eradicate biofilms but do induce SCVs and antibiotic-tolerant cells. These effects may accelerate the transition from biofilm to chronic infection. Thus, octanoic acid exhibits bactericidal action against <em>S. aureus</em> biofilms, and it is less likely than antibiotic therapy to induce persistent cells and pathogen tolerance. Moreover, octanoic acid acts additively with antibiotics against <em>S. aureus</em>, and it attenuates tetracycline-induced virulence factor gene expression in <em>S. aureus</em> cells. According to these data, octanoic acid may prevent the pathological progression of bovine mastitis and offer a new strategy for treating the condition.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":6.8,"publicationDate":"2023-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combining phages and antibiotic to enhance antibiofilm efficacy against an in vitro dual species wound biofilm","authors":"Ergun Akturk ,&nbsp;Luís D.R. Melo ,&nbsp;Hugo Oliveira ,&nbsp;Aurélie Crabbé ,&nbsp;Tom Coenye ,&nbsp;Joana Azeredo","doi":"10.1016/j.bioflm.2023.100147","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100147","url":null,"abstract":"<div><p>Chronic wound management is extremely challenging because of the persistence of biofilm-forming pathogens, such as <em>Pseudomonas aeruginosa</em> and <em>Staphylococcus aureus</em>, which are the prevailing bacterial species that co-infect chronic wounds. Phage therapy has gained an increased interest to treat biofilm-associated infections, namely when combined with antibiotics. Here, we tested the effect of gentamicin as a co-adjuvant of phages in a dual species-biofilm wound model formed on artificial dermis. The biofilm-killing capacity of the tested treatments was significantly increased when phages were combined with gentamicin and applied multiple times as multiple dose (three doses, every 8 h). Our results suggest that gentamycin is an effective adjuvant of phage therapy particularly when applied simultaneously with phages and in three consecutive doses. The multiple and simultaneous dose treatment seems to be essential to avoid bacterial resistance development to each of the antimicrobial agents.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":6.8,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cladosporium sphaerospermum extract inhibits quorum sensing associated virulence factors of Serratia marcescens","authors":"Dan-Rui Liu ,&nbsp;Qing-Xiang Yan ,&nbsp;Zheng-Biao Zou ,&nbsp;Chun-Lan Xie ,&nbsp;Xian-Wen Yang ,&nbsp;Ai-Qun Jia","doi":"10.1016/j.bioflm.2023.100146","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100146","url":null,"abstract":"<div><p><em>Serratia marcescens</em> is now becoming a propensity for its highly antimicrobial-resistant clinical infections. Currently, it provides a novel strategy to prevent and control microbial infection by regulating <em>S. marcescens</em> quorum sensing (QS). Deep-sea-derived fungi are rich in QS bioactive constituents. In this work, the extracts from <em>Cladosporium sphaerospermum</em> SCSGAF0054 showed potent QS-related virulence factors and biofilm-inhibiting activities against <em>S. marcescens</em> NJ01<em>.</em> The swimming motility and multiple virulence factors such as prodigiosin, exopolysaccharide (EPS), lipase, protease and hemolysin were moderately inhibited by the extracts at varied concentrations. The confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) images revealed that <em>C. sphaerospermum</em> extracts moderately arrested biofilm formation and cell viability. Further, real-time quantitative PCR (RT-qPCR) analysis revealed that expressions of genes associated with virulence factors, <em>flhD</em>, <em>fimA</em>, <em>fimC</em>, <em>bsmA</em>, <em>bsmB</em>, <em>pigA</em>, <em>pigC</em>, and <em>shlA</em>, were significantly down-regulated compared with control. In addition, the extracts combined with imipenem inhibited the QS system of <em>S. marcescens</em> NJ01, disrupted its preformed biofilm, released the intra-biofilm bacteria and killed the bacteria gradually. Therefore, the extracts combined with imipenem can partially restore bacterial drug sensitivity. These results suggest that the extracts from SCSGAF0054 effectively interfere with the QS system to treat <em>S. marcescens</em> infection alone or combining with classical antimicrobial drugs.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":6.8,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biochemical characterization and mercury methylation capacity of Geobacter sulfurreducens biofilms grown in media containing iron hydroxide or fumarate","authors":"Elena Yunda,&nbsp;Quynh Nhu Phan Le,&nbsp;Erik Björn,&nbsp;Madeleine Ramstedt","doi":"10.1016/j.bioflm.2023.100144","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100144","url":null,"abstract":"<div><p><em>Geobacter</em> species are common in iron-rich environments and can contribute to formation of methylmercury (MeHg), a neurotoxic compound with high bioaccumulation potential formed as a result of bacterial and archaeal physiological activity. <em>Geobacter sulfurreducens</em> can utilize various electron acceptors for growth including iron hydroxides or fumarate. However, it remains poorly understood how the growth on these compounds affects physiological properties of bacterial cells in biofilms, including the capacity to produce MeHg. The purpose of this study was to determine changes in the biochemical composition of <em>G. sulfurreducens</em> during biofilm cultivation in media containing iron hydroxide or fumarate, and to quantify mercury (Hg) methylation capacity of the formed biofilms. Biofilms were characterized by Fourier-transform infrared spectroscopy in the attenuated total reflection mode (ATR-FTIR), Resonance Raman spectroscopy and confocal laser scanning microscopy. MeHg formation was quantified by mass spectrometry after incubation of biofilms with 100 nM Hg. The results of ATR-FTIR experiments showed that in presence of fumarate, <em>G. sulfurreducens</em> biofilm formation was accompanied by variation in content of the energy-reserve polymer glycogen over time, which could be cancelled by the addition of supplementary nutrients (yeast extract). In contrast, biofilms cultivated on Fe(III) hydroxide did not accumulate glycogen. The ATR-FTIR results further suggested that Fe(III) hydroxide surfaces bind cells via phosphate and carboxylate groups of bacteria that form complexes with iron. Furthermore, biofilms grown on Fe(III) hydroxide had higher fraction of oxidized cytochromes and produced two to three times less biomass compared to conditions with fumarate. Normalized to biofilm volume, the content of MeHg was similar in assays with biofilms grown on Fe(III) hydroxide and on fumarate (with yeast extract and without). These results suggest that <em>G. sulfurreducens</em> biofilms produce MeHg irrespectively from glycogen content and cytochrome redox state in the cells, and warrant further investigation of the mechanisms controlling this process.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":6.8,"publicationDate":"2023-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}