Biofilm最新文献

{"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":"6 ","pages":"Article 100147"},"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":"6 ","pages":"Article 100146"},"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":"6 ","pages":"Article 100144"},"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}

{"title":"Resistance of aerobic granular sludge microbiomes to periodic loss of biomass","authors":"Raquel Liébana ,&nbsp;Oskar Modin ,&nbsp;Frank Persson ,&nbsp;Malte Hermansson ,&nbsp;Britt-Marie Wilén","doi":"10.1016/j.bioflm.2023.100145","DOIUrl":"10.1016/j.bioflm.2023.100145","url":null,"abstract":"<div><p>Granular sludge is a biofilm process used for wastewater treatment which is currently being implemented worldwide. It is important to understand how disturbances affect the microbial community and performance of reactors. Here, two acetate-fed replicate reactors were inoculated with acclimatized sludge and the reactor performance, and the granular sludge microbial community succession were studied for 149 days. During this time, the microbial community was challenged by periodically removing half of the reactor biomass, subsequently increasing the food-to-microorganism (F/M) ratio. Diversity analysis together with null models show that overall, the microbial communities were resistant to the disturbances, observing some minor effects on polyphosphate-accumulating and denitrifying microbial communities and their associated reactor functions. Community turnover was driven by drift and random granule loss, and stochasticity was the governing ecological process for community assembly. These results evidence the aerobic granular sludge process as a robust system for wastewater treatment.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"6 ","pages":"Article 100145"},"PeriodicalIF":6.8,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10415711/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10371416","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":"Biofilm reactors for the treatment of used water in space:potential, challenges, and future perspectives","authors":"Erika J. Espinosa-Ortiz ,&nbsp;Robin Gerlach ,&nbsp;Brent M. Peyton ,&nbsp;Luke Roberson ,&nbsp;Daniel H. Yeh","doi":"10.1016/j.bioflm.2023.100140","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100140","url":null,"abstract":"<div><p>Water is not only essential to sustain life on Earth, but also is a crucial resource for long-duration deep space exploration and habitation. Current systems in space rely on the resupply of water from Earth, however, as missions get longer and move farther away from Earth, resupply will no longer be a sustainable option. Thus, the development of regenerative reclamation water systems through which useable water can be recovered from “waste streams” (<em>i.e.,</em> used waters) is sorely needed to further close the loop in space life support systems. This review presents the origin and characteristics of different used waters generated in space and discusses the intrinsic challenges of developing suitable technologies to treat such streams given the unique constrains of space exploration and habitation (<em>e.g.</em>, different gravity conditions, size and weight limitations, compatibility with other systems, <em>etc.</em>). In this review, we discuss the potential use of biological systems, particularly biofilms, as possible alternatives or additions to current technologies for water reclamation and waste treatment in space. The fundamentals of biofilm reactors, their advantages and disadvantages, as well as different reactor configurations and their potential for use and challenges to be incorporated in self-sustaining and regenerative life support systems in long-duration space missions are also discussed. <span>Furthermore</span>, we discuss the possibility to recover value-added products (<em>e.g.</em>, biomass, nutrients, water) from used waters and the opportunity to recycle and reuse such products as resources in other life support subsystems (<em>e.g.,</em> habitation, waste, air, <em>etc</em>.).</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"6 ","pages":"Article 100140"},"PeriodicalIF":6.8,"publicationDate":"2023-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171123","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":"Sucrose-mediated formation and adhesion strength of Streptococcus mutans biofilms on titanium","authors":"Laura J. Waldman ,&nbsp;Tony Butera ,&nbsp;James D. Boyd ,&nbsp;Martha E. Grady","doi":"10.1016/j.bioflm.2023.100143","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100143","url":null,"abstract":"<div><p>Biofilms consist of bacterial cells surrounded by a matrix of extracellular polymeric substance (EPS), which protects the colony from many countermeasures, including antibiotic treatments. Growth and formation of bacterial biofilms are affected by nutrients available in the environment. In the oral cavity, the presence of sucrose affects the growth of <em>Streptococcus mutans</em> that produce acids that erode enamel and form dental caries. Biofilm formation on dental implants commonly leads to severe infections and can restrict osseointegration necessary for the implant to be successful. This work determines the effect of sucrose concentration on biofilm EPS formation and adhesion of <em>Streptococcus mutans</em>, a common oral colonizer, to titanium substrates simulating common dental implants. Biofilm formation and profiles are visualized at high magnification with scanning electron microscopy (SEM). Large mounds and complex structures consisting of bacterial cells and EPS can be seen in biofilms at sucrose concentrations that are favorable for biofilm growth. The laser spallation technique is used to apply stress wave loading to the biofilm, causing the biofilm to delaminate at a critical tensile stress threshold. The critical tensile stress threshold is the adhesion strength. Because laser spallation applies the stress loading to the rear of the substrate, bulk adhesion properties of the biofilm can be determined despite the heterogenous composition and low cohesion strength of the biofilm. Statistical analysis reveals that adhesion strength of biofilms initially increase with increasing sucrose concentration and then decrease as sucrose concentration continues to increase. The adhesion strength of bacterial biofilms to the substrate in this study is compared to the adhesion of osteoblast-like cells to the same substrates published previously. When sucrose is present in the biofilm growth environment, <em>S. mutans</em> adhesion is higher than that of the osteoblast-like cells. Results of this study suggest sucrose-mediated <em>S. mutans</em> biofilms may outcompete osteoblasts in terms of adhesion during osseointegration, which could explain higher rates of peri-implant disease associated with high sugar diets. Further studies demonstrating adhesion differentials between biofilms and cells including co-cultures are needed and motivated by the present work.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"6 ","pages":"Article 100143"},"PeriodicalIF":6.8,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171124","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":"Ex vivo comparison of V.A.C.® Granufoam Silver™ and V.A.C.® Granufoam™ loaded with a first-in-class bis-dialkylnorspermidine-terphenyl antibiofilm agent","authors":"Kaden B. Rawson ,&nbsp;Travis Neuberger ,&nbsp;Tyler B. Smith ,&nbsp;Isaac J. Bell ,&nbsp;Ryan E. Looper ,&nbsp;Paul R. Sebahar ,&nbsp;Travis J. Haussener ,&nbsp;Hariprasada Reddy Kanna Reddy ,&nbsp;Brad M. Isaacson ,&nbsp;John Shero ,&nbsp;Paul F. Pasquina ,&nbsp;Dustin L. Williams","doi":"10.1016/j.bioflm.2023.100142","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100142","url":null,"abstract":"<div><p>Implementation of negative pressure wound therapy (NPWT) as a standard of care has proven efficacious in reducing both the healing time and likelihood of nosocomial infection among pressure ulcers and traumatic, combat-related injuries. However, current formulations may not target or dramatically reduce bacterial biofilm burden following therapy. The purpose of this study was to determine the antibiofilm efficacy of an open-cell polyurethane (PU) foam (V.A.C.® Granufoam™) loaded with a first-in-class compound (CZ-01179) as the active release agent integrated via lyophilized hydrogel scaffolding. An <em>ex vivo</em> porcine excision wound model was designed to perform antibiofilm efficacy testing in the presence of NPWT. PU foam samples loaded with a 10.0% w/w formulation of CZ-01179 and 0.5% hyaluronic acid were prepared and tested against current standards of care: V.A.C.® Granufoam Silver™ and V.A.C.® Granufoam™. We observed statistically significant reduction of methicillin-resistant <em>Staphylococcus aureus</em> (MRSA) and <em>Acinetobacter baumannii</em> biofilms with the CZ-01179 antibiofilm foam in comparison to current standard of care foams. These findings motivate further development of an antibiofilm PU foam loaded with CZ-01179.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"6 ","pages":"Article 100142"},"PeriodicalIF":6.8,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171122","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":"To update or not to update the ESCMID guidelines for the diagnosis and treatment of biofilm infections – That is the question! The opinion of the ESGB board","authors":"Niels Høiby ,&nbsp;Claus Moser ,&nbsp;Antonio Oliver ,&nbsp;Craig Williams ,&nbsp;Gordon Ramage ,&nbsp;Elisa Borghi ,&nbsp;Joana Azeredo ,&nbsp;Maria Dolores Macia ,&nbsp;for the ESGB board","doi":"10.1016/j.bioflm.2023.100135","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100135","url":null,"abstract":"<div><h3>Background</h3><p>The work on the ESGB guidelines for diagnosis and treatment of biofilm infections began in 2012 and the result was published in 2014. The guidelines have been and still are frequently cited in the literature proving its usefulness for people working with biofilm infections. At the ESGB Biofilm conference in Mallorca 2022 (Eurobiofilms2022) the board of the ESGB decided to evaluate the 2014-guidelines and relevant publications since 2014 based on a lecture given at the Eurobiofilms2022.</p></div><div><h3>Guideline methods</h3><p>The Delphi method for working on production of guidelines and the current ESCMID rules for guidelines are presented. The criteria for evaluation of relevant literature are very strict and especially for treatment, most clinicians and regulatory authorities require convincing results from Level I (randomized controlled trials) publications to justify changes of treatments. The relevant new biofilm literature and the relevant biofilm presentations from the Eurobiofilms meetings and ECCMID conferences was used for evaluating the contemporary relevance of the ESGB 2014 guidelines.</p></div><div><h3>Diagnosis of biofilm infections</h3><p>Several infectious diseases have been recognized as biofilm infections since 2014, but the diagnostic methods and therapeutic strategies are still the same as recommended in the 2014 ESGB guidelines which are summarized in this opinion paper.</p></div><div><h3>Treatment of biofilm infections</h3><p>Some promising new <em>in vitro</em> and <em>in vivo</em> (animal experiments) observations and reports for therapy of biofilm infections are mentioned, but they still await clinical trials.</p></div><div><h3>Conclusion</h3><p>The interim opinion at the present time (2022) is therefore, that the guidelines do not need revision now, but there is a need for survey articles discussing new methods of diagnosis and treatment of biofilm infections in order - hopefully – to give inspiration to conduct clinical trials which may lead to progress in diagnosis and treatment of patients with biofilm infections.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"6 ","pages":"Article 100135"},"PeriodicalIF":6.8,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171121","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":"Investigating the chemical pathway to the formation of a single biofilm using infrared spectroscopy","authors":"Amy R. Crisp ,&nbsp;Bryn Short ,&nbsp;Laurence Rowan ,&nbsp;Gordon Ramage ,&nbsp;Ihtesham U.R. Rehman ,&nbsp;Robert D. Short ,&nbsp;Craig Williams","doi":"10.1016/j.bioflm.2023.100141","DOIUrl":"10.1016/j.bioflm.2023.100141","url":null,"abstract":"<div><p>Diagnosing biofilm infections has remained a constant challenge for the last 50 years. Existing diagnostic methods struggle to identify the biofilm phenotype. Moreover, most methods of biofilm analysis destroy the biofilm making the resultant data interpretation difficult. In this study we introduce Fourier Transform Infra-Red (FTIR) spectroscopy as a label-free, non-destructive approach to monitoring biofilm progression. We have utilised FTIR in a novel application to evaluate the chemical composition of bacterial biofilms without disrupting the biofilm architecture. <em>S. epidermidis</em> (RP62A) was grown onto calcium fluoride slides for periods of 30 min–96 h, before semi-drying samples for analysis. We report the discovery of a chemical marker to distinguish between planktonic and biofilm samples. The appearance of new proteins in biofilm samples of varying maturity is exemplified in the spectroscopic data, highlighting the potential of FTIR for identifying the presence and developmental stage of a single biofilm.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"6 ","pages":"Article 100141"},"PeriodicalIF":6.8,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/05/d3/main.PMC10336410.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9823779","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":"The effect of sex steroid hormones on the ecology of in vitro oral biofilms","authors":"Pilar Cornejo Ulloa,&nbsp;Monique H. van der Veen,&nbsp;Bernd W. Brandt,&nbsp;Mark J. Buijs,&nbsp;Bastiaan P. Krom","doi":"10.1016/j.bioflm.2023.100139","DOIUrl":"https://doi.org/10.1016/j.bioflm.2023.100139","url":null,"abstract":"<div><p>Sex steroid hormones (SSH) such as oestrogen, progesterone and testosterone are cholesterol derived molecules that regulate various physiological processes. They are present in both blood and saliva, where they come in contact with oral tissues and oral microorganisms. Several studies have confirmed the effect of these hormones on different periodontal-disease-associated bacteria, using single-species models. Bacteria can metabolize SSH, use them as alternative for vitamin K and also use them to induce the expression of virulence factors. However, it is still unclear what the effects of SSH are on the oral microbiome. In this study, we investigated the effects of four SSH on commensal <em>in vitro</em> oral biofilms. Saliva-derived oral biofilms were grown in Mc Bain medium without serum or menadione using the Amsterdam Active-Attachment model. After initial attachment in absence of SSH, the biofilms were grown in medium containing either oestradiol, oestriol, progesterone or testosterone at a 100-fold physiological concentration. Menadione or ethanol were included as positive control and negative control, respectively. After 12 days with daily medium refreshments, biofilm formation, biofilm red fluorescence and microbial composition were determined. The supernatants were tested for proteolytic activity using the Fluorescence Resonance Energy Transfer Analysis (FRET). No significant differences were found in biofilm formation, red fluorescence or microbial composition in any of the tested groups. Samples grown in presence of progesterone and oestradiol showed proteolytic activity comparable to biofilms supplemented with menadione. In contrast, testosterone and oestriol showed a decreased proteolytic activity compared to biofilms grown in presence of menadione.</p><p>None of the tested SSH had large effects on the ecology of <em>in vitro</em> oral biofilms, therefore a direct translation of our results into <em>in vivo</em> effects is not possible. Future experiments should include other host factors such as oral tissues, immune cells and combinations of SSH as present in saliva, in order to have a more accurate picture of the phenomena taking place in both males and females.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"6 ","pages":"Article 100139"},"PeriodicalIF":6.8,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50171120","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}