Biofilm最新文献

{"title":"Pseudomonas aeruginosa quorum sensing and biofilm attenuation by a di-hydroxy derivative of piperlongumine (PL-18)","authors":"Yael Schlichter Kadosh ,&nbsp;Subramani Muthuraman ,&nbsp;Khairun Nisaa ,&nbsp;Anat Ben-Zvi ,&nbsp;Danit Lisa Karsagi Byron ,&nbsp;Marilou Shagan ,&nbsp;Alexander Brandis ,&nbsp;Tevie Mehlman ,&nbsp;Jacob Gopas ,&nbsp;Rajendran Saravana Kumar ,&nbsp;Ariel Kushmaro","doi":"10.1016/j.bioflm.2024.100215","DOIUrl":"10.1016/j.bioflm.2024.100215","url":null,"abstract":"<div><p>Bacterial communication, Quorum Sensing (QS), is a target against virulence and prevention of antibiotic-resistant infections. 16 derivatives of Piperlongumine (PL), an amide alkaloid from <em>Piper longum</em> L., were screened for QS inhibition. PL-18 had the best QSI activity. PL-18 inhibited the <em>lasR-lasI, rhlR-rhlI,</em> and <em>pqs</em> QS systems of <em>Pseudomonas aeruginosa</em>. PL-18 inhibited pyocyanin and rhamnolipids that are QS-controlled virulence elements. Iron is an essential element for pathogenicity, biofilm formation and resilience in harsh environments, its uptake was inhibited by PL-18. Pl-18 significantly reduced the biofilm biovolume including in established biofilms. PL-18-coated silicon tubes significantly inhibited biofilm formation. The transcriptome study of treated <em>P. aeruginosa</em> showed that PL-18 indeed reduced the expression of QS and iron homeostasis related genes, and up regulated sulfur metabolism related genes. Altogether, PL-18 inhibits QS, virulence, iron uptake, and biofilm formation. Thus, PL-18 should be further developed against bacterial infection, antibiotic resistance, and biofilm formation.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100215"},"PeriodicalIF":5.9,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000406/pdfft?md5=d5f54150d637486fcc088113ac106d80&pid=1-s2.0-S2590207524000406-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141839786","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":"Intra-strain colony biofilm heterogeneity in uropathogenic Escherichia coli and the effect of the NlpI lipoprotein","authors":"Hamilton D. Green ,&nbsp;Gerald T. Van Horn ,&nbsp;Timothy Williams ,&nbsp;Allison Eberly ,&nbsp;Grace H. Morales ,&nbsp;Robert Mann ,&nbsp;Indiana M. Hauter ,&nbsp;Maria Hadjifrangiskou ,&nbsp;Jonathan E. Schmitz","doi":"10.1016/j.bioflm.2024.100214","DOIUrl":"10.1016/j.bioflm.2024.100214","url":null,"abstract":"<div><p>Biofilm growth facilitates the interaction of uropathogenic <em>Escherichia coli</em> (UPEC) with the host environment. The extracellular polymeric substances (EPS) of UPEC biofilms are composed prominently of curli amyloid fiber and cellulose polysaccharide. When the organism is propagated as a colony biofilm on agar media, these macromolecules can generate pronounced macroscopic structures. Moreover, curli/cellulose associate tightly with Congo red, generating a characteristic pink-to-red staining pattern when the media is supplemented with this dye. Among different clinical isolates of UPEC, changes in the abundance of curli/cellulose can lead to diverse colony biofilm phenotypes on a strain-by-strain basis. Nevertheless, for any given isolate, these phenotypes are classically homogenous throughout the colony biofilm. Here, we report that a subset of clinical UPEC isolates display heterogenous ‘peppermint’ colony biofilms, with distinct pale and red subpopulations. Through isolation of these subpopulations and whole genome sequencing, we demonstrate various emergent mutations associated with the phenomenon, including within the gene encoding the outer membrane lipoprotein <em>nlpI</em>. Deletion of <em>nlpI</em> within independent strain-backgrounds increased biofilm rugosity, while its overexpression induced the peppermint phenotype. Upregulation of EPS-associated proteins and transcripts was likewise observed in the absence of <em>nlpI</em>. Overall, these results demonstrate that EPS elaboration in UPEC is impacted by <em>nlpI</em>. More broadly, this phenomenon of intra-strain colony biofilm heterogeneity may be leveraged as a tool to identify additional members within the broad collection of genes that regulate or otherwise affect biofilm formation.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100214"},"PeriodicalIF":5.9,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S259020752400039X/pdfft?md5=1c8e88b80f11d17ebcd57389f0455a51&pid=1-s2.0-S259020752400039X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141845904","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":"d-Methionine-induced DNases disperse established Burkholderia pseudomallei biofilms and promotes ceftazidime susceptibility","authors":"Rattiyaphorn Pakkulnan ,&nbsp;Auttawit Sirichoat ,&nbsp;Sorujsiri Chareonsudjai","doi":"10.1016/j.bioflm.2024.100213","DOIUrl":"10.1016/j.bioflm.2024.100213","url":null,"abstract":"<div><p><em>Burkholderia pseudomallei</em> biofilm is correlated with pathogenesis, antibiotic resistance, and relapsing cases of melioidosis, leading to challenges in clinical management. There is increasing interest in employing biofilm dispersal agents as adjunctive treatments for biofilm-associated infections. Methionine (Met) has shown promise as an anti-biofilm agent by inducing bacterial DNase production, resulting in the degradation of extracellular DNA (eDNA) and dispersion of bacterial biofilm. In this study, we investigated the impact of 0.05–50 μM D-Met and L-Met on the 24-h established biofilm of a clinical isolate, <em>B. pseudomallei</em> H777. Our findings revealed the ability of D-Met and L-Met to disperse the established biofilm in a non-dose-dependent manner accompanied by eDNA depletion. Real-time PCR analysis further identified an up-regulation of bacterial nuclease genes, including <em>recJ</em>, <em>eddB</em>, <em>nth</em>, <em>xth</em>, and <em>recD,</em> in the presence of 0.05 μM D-Met. Similarly, <em>recJ</em> and <em>eddB</em> in <em>B. pseudomallei</em> were up-regulated in response to the presence of 0.05 μM L-Met. Notably, D-Met enhanced the susceptibility of <em>B. pseudomallei</em> H777 biofilm cells to ceftazidime. Our findings indicate a correlation between methionine supplementation and the up-regulation of nuclease genes, leading to eDNA depletion and the dispersal of preformed <em>B. pseudomallei</em> H777 biofilm. This enhances the susceptibility of biofilm cells to ceftazidime, showing promise in combating biofilm-associated <em>B. pseudomallei</em> infections.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100213"},"PeriodicalIF":5.9,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000388/pdfft?md5=1de1bbe8ed2c7737cf33f49a0e39809c&pid=1-s2.0-S2590207524000388-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141708369","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 maturation of native uropathogenic Escherichia coli biofilms seen through a non-interventional lens","authors":"Tianqi Zhang ,&nbsp;Sanhita Ray ,&nbsp;Keira Melican ,&nbsp;Agneta Richter-Dahlfors","doi":"10.1016/j.bioflm.2024.100212","DOIUrl":"10.1016/j.bioflm.2024.100212","url":null,"abstract":"<div><p>Urinary tract infections (UTI) caused by uropathogenic <em>Escherichia coli</em> (UPEC) are a significant global health challenge. The UPEC biofilm lifestyle is believed to play an important role in infection recurrency and treatment resistance, but our understanding of how the extracellular matrix (ECM) components curli and cellulose contribute to biofilm formation and pathogenicity is limited. Here, we study the spatial and temporal development of native UPEC biofilm using agar-based detection methods where the non-toxic, optically active fluorescent tracer EbbaBiolight 680 reports the expression and structural location of curli in real-time. An <em>in vitro</em> screen of the biofilm capacity of common UPEC strains reveals significant strain variability and identifies UPEC No. 12 (UPEC12) as a strong biofilm former at 28 °C and 37 °C. Non-interventional microscopy, including time-lapse and 2-photon, reveal significant horizontal and vertical heterogeneity in the UPEC12 biofilm structure. We identify region-specific expression of curli, with a shift in localization from the bottom of the flat central regions of the biofilm to the upper surface in the topographically dramatic intermediate region. When investigating if the rdar morphotype affects wettability of the biofilm surface, we found that the nano-architecture of curli guided by cellulose, rather than the rdar macrostructures, leads to increased hydrophobicity of the biofilm. By providing new insights at exceptional temporal and spatial resolution, we demonstrate how non-interventional analysis of native biofilms will facilitate the next generation of understanding into the roles of ECM components during growth of UPEC biofilms and their contribution to the pathogenesis of UTI.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100212"},"PeriodicalIF":5.9,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000376/pdfft?md5=686f47897b4df26bfcbcb4f12961721c&pid=1-s2.0-S2590207524000376-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630769","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":"Global challenges and microbial biofilms: Identification of priority questions in biofilm research, innovation and policy","authors":"Tom Coenye ,&nbsp;Merja Ahonen ,&nbsp;Skip Anderson ,&nbsp;Miguel Cámara ,&nbsp;Parvathi Chundi ,&nbsp;Matthew Fields ,&nbsp;Ines Foidl ,&nbsp;Etienne Z. Gnimpieba ,&nbsp;Kristen Griffin ,&nbsp;Jamie Hinks ,&nbsp;Anup R. Loka ,&nbsp;Carol Lushbough ,&nbsp;Cait MacPhee ,&nbsp;Natasha Nater ,&nbsp;Rasmita Raval ,&nbsp;Jo Slater-Jefferies ,&nbsp;Pauline Teo ,&nbsp;Sandra Wilks ,&nbsp;Maria Yung ,&nbsp;Biofilm Priority Questions Exercise Participants ,&nbsp;Jeremy S. Webb","doi":"10.1016/j.bioflm.2024.100210","DOIUrl":"10.1016/j.bioflm.2024.100210","url":null,"abstract":"<div><p>Priority question exercises are increasingly used to frame and set future research, innovation and development agendas. They can provide an important bridge between the discoveries, data and outputs generated by researchers, and the information required by policy makers and funders. Microbial biofilms present huge scientific, societal and economic opportunities and challenges. In order to identify key priorities that will help to advance the field, here we review questions from a pool submitted by the international biofilm research community and from practitioners working across industry, the environment and medicine. To avoid bias we used computational approaches to group questions and manage a voting and selection process. The outcome of the exercise is a set of 78 unique questions, categorized in six themes: (i) Biofilm control, disruption, prevention, management, treatment (13 questions); (ii) Resistance, persistence, tolerance, role of aggregation, immune interaction, relevance to infection (10 questions); (iii) Model systems, standards, regulatory, policy education, interdisciplinary approaches (15 questions); (iv) Polymicrobial, interactions, ecology, microbiome, phage (13 questions); (v) Clinical focus, chronic infection, detection, diagnostics (13 questions); and (vi) Matrix, lipids, capsule, metabolism, development, physiology, ecology, evolution environment, microbiome, community engineering (14 questions). The questions presented are intended to highlight opportunities, stimulate discussion and provide focus for researchers, funders and policy makers, informing future research, innovation and development strategy for biofilms and microbial communities.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100210"},"PeriodicalIF":5.9,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000352/pdfft?md5=883e17aa6557cf972a1d0c614c8741b2&pid=1-s2.0-S2590207524000352-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141712422","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":"Yielding behaviour of chemically treated Pseudomonas fluorescens biofilms","authors":"Samuel G.V. Charlton ,&nbsp;Saikat Jana ,&nbsp;Jinju Chen","doi":"10.1016/j.bioflm.2024.100209","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100209","url":null,"abstract":"<div><p>The mechanics of biofilms are intrinsically shaped by their physicochemical environment. By understanding the influence of the extracellular matrix composition, pH and elevated levels of cationic species on the biofilm rheology, novel living materials with tuned properties can be formulated. In this study, we examine the role of a chaotropic agent (urea), two divalent cations and distilled deionized water on the nonlinear viscoelasticity of a model biofilm <em>Pseudomonas fluorescens</em>. The structural breakdown of each biofilm is quantified using tools of non-linear rheology. Our findings reveal that urea induced a softening response, and displayed strain overshoots comparable to distilled deionized water, without altering the microstructural packing fraction and macroscale morphology. The absorption of divalent ferrous and calcium cations into the biofilm matrix resulted in stiffening and a reduction in normalized elastic energy dissipation, accompanied by macroscale morphological wrinkling and moderate increases in the packing fraction. Notably, ferrous ions induced a predominance of rate dependent yielding, whereas the calcium ions resulted in equal contribution from both rate and strain dependent yielding and structural breakdown of the biofilms. Together, these results indicate that strain rate increasingly becomes an important factor controlling biofilm fluidity with cation-induced biofilm stiffening. The finding can help inform effective biofilm removal protocols and in development of bio-inks for additive manufacturing of biofilm derived materials.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100209"},"PeriodicalIF":5.9,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000340/pdfft?md5=e0fa5ba7428e1a9a6cb181f197016457&pid=1-s2.0-S2590207524000340-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141592927","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":"A bacteriocin-based coating strategy to prevent vancomycin-resistant Enterococcus faecium biofilm formation on materials of interest for indwelling medical devices","authors":"Christian Kranjec ,&nbsp;Jills Puthiaparambil Mathew ,&nbsp;Kirill Ovchinnikov ,&nbsp;Idowu Fadayomi ,&nbsp;Ying Yang ,&nbsp;Morten Kjos ,&nbsp;Wen-Wu Li","doi":"10.1016/j.bioflm.2024.100211","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100211","url":null,"abstract":"<div><p>The ever-increasing use of exogenous materials as indwelling medical devices in modern medicine offers to pathogens new ways to gain access to human body and begin, in some cases, life threatening infections. Biofouling of such materials with bacteria or fungi is a major concern during surgeries, since this is often associated with biofilm formation and difficult to treat, recalcitrant infections. Intense research efforts have therefore developed several strategies to shield the medical devices' surface from colonization by pathogenic microorganisms. Here, we used dopamine as a coupling agent to coat four different materials of medical interest (plastic polyetheretherketone (PEEK), stainless steel, titanium and silicone catheter) with the bacteriocins, enterocin EJ97-short and the thiopeptide micrococcin P1. Water contact angle measurements and x-ray photoelectron spectroscopy were used to verify the effective coating of the materials. The effect of bacteriocins coated on these materials on the biofilm formation by a vancomycin resistant <em>Enterococcus faecium</em> (VRE) strain was studied by biofilm-oriented antimicrobial test (BOAT) and electron scanning microscopy. The <em>in vitro</em> biocompatibility of bacteriocin-modified biomaterials was tested on cultured human cells. The results demonstrated that the binding of the bacteriocins to the implant surfaces is achieved, and the two bacteriocins in combination could inhibit biofilm formation by <em>E. faecium</em> on all four materials. The modified implant showed no cytotoxicity to the human cells tested. Therefore, surface modification with the two bacteriocins may offer a novel and effective way to prevent biofilm formation on a wide range of implant materials.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100211"},"PeriodicalIF":5.9,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000364/pdfft?md5=6a812a9466c80e7d2f49afa80a40ef5d&pid=1-s2.0-S2590207524000364-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141592926","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":"Dopamine, an exogenous quorum sensing signaling molecule or a modulating factor in Pseudomonas aeruginosa?","authors":"Shi-Liang Xiang ,&nbsp;Kai-Zhong Xu ,&nbsp;Lu-Jun Yin ,&nbsp;Yong Rao ,&nbsp;Bo Wang ,&nbsp;Ai-Qun Jia","doi":"10.1016/j.bioflm.2024.100208","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100208","url":null,"abstract":"<div><p><em>Pseudomonas aeruginosa</em> is recognized globally as an opportunistic pathogen of considerable concern due to its high virulence and pathogenicity, especially in immunocompromised individuals. While research has identified several endogenous quorum sensing (QS) signaling molecules that enhance the virulence and pathogenicity of <em>P. aeruginosa</em>, investigations on exogenous QS signaling molecules or modulating factors remain limited. This study found that dopamine serves as an exogenous QS signaling molecule or modulating factor of <em>P. aeruginosa</em> PAO1, enhancing the production of virulence factors and biofilms. Compared to the control group, treatment with 40 μM dopamine resulted in a 33.1 % increase in biofilm formation, 68.1 % increase in swimming mobility, 63.1 % increase in swarming mobility, 147.2 % increase in the signaling molecule 3-oxo-C12-HSL, and 50.5 %, 28.5 %, 27.0 %, and 33.2 % increases in the virulence factors alginate, rhamnolipids, protease, and pyocyanin, respectively. This study further explored the mechanism of dopamine regulating the biofilm formation and virulence of <em>P. aeruginosa</em> PAO1 through transcriptome and metabolome. Transcriptomic analysis showed that dopamine promoted the expression of virulence genes <em>psl, alg, lasA, rhlABC</em>, <em>rml</em>, and <em>phz</em> in <em>P. aeruginosa</em> PAO1. Metabolomic analysis revealed changes in the concentrations of tryptophan, pyruvate, ethanolamine, glycine, 3-hydroxybutyric acid, and alizarin. Furthermore, KEGG enrichment analysis of altered genes and metabolites indicated that dopamine enhanced phenylalanine, tyrosine, and tryptophan in <em>P. aeruginosa</em> PAO1. The results of this study will contribute to the development of novel exogenous QS signaling molecules or modulating factors and advance our understanding of the interactions between <em>P. aeruginosa</em> and the host environment.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100208"},"PeriodicalIF":5.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000339/pdfft?md5=33d4e083969c17e1f4fdc34a2d89b8ea&pid=1-s2.0-S2590207524000339-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141487331","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 dynamics of biofilm development and dispersal should be taken into account when quantifying biofilm via the crystal violet microtiter plate assay","authors":"Jens Bo Andersen,&nbsp;Morten Rybtke,&nbsp;Tim Tolker-Nielsen","doi":"10.1016/j.bioflm.2024.100207","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100207","url":null,"abstract":"<div><p>The crystal violet microtiter plate biofilm assay is often used to compare the amount of biofilm formed by a mutant versus wild-type or a compound-treated biofilm versus the non-treatment control. In many of these studies the amount of biofilm is assessed only at one single time point. However, if the dynamics of biofilm development of the mutant (or compound-treated biofilm) is different than that of the wild-type (or non-treatment control), then biofilm quantification at a single time point may give misleading results. To overcome this shortcoming of the common biofilm quantification technique, we recommend to use a serial dilution-based crystal violet microtiter plate biofilm assay for easy assessment of the dynamics of biofilm development and dispersal. We demonstrate that the dilution-resolved crystal violet assay displays the dynamics of <em>Pseudomonas aeruginosa</em> biofilm development and dispersal as efficient as a time-resolved crystal violet assay. In addition, focusing on mutants of different parts of the c-di-GMP signaling system in <em>P. aeruginosa</em>, we provide an example illustrating the need to assess biofilm dynamics instead of quantifying biofilm biomass at a single time point.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100207"},"PeriodicalIF":5.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000327/pdfft?md5=21e154782abc4bbe0cdc803a1b46ecec&pid=1-s2.0-S2590207524000327-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141438432","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":"Myrtus communis leaf compounds as novel inhibitors of quorum sensing-regulated virulence factors and biofilm formation: In vitro and in silico investigations","authors":"Nadine Khadraoui ,&nbsp;Rym Essid ,&nbsp;Bilel Damergi ,&nbsp;Nadia Fares ,&nbsp;Dorra Gharbi ,&nbsp;Abel Mateo Forero ,&nbsp;Jaime Rodríguez ,&nbsp;Ghassen Abid ,&nbsp;Erika-Beáta Kerekes ,&nbsp;Ferid Limam ,&nbsp;Carlos Jiménez ,&nbsp;Olfa Tabbene","doi":"10.1016/j.bioflm.2024.100205","DOIUrl":"10.1016/j.bioflm.2024.100205","url":null,"abstract":"<div><p>Antibiotic resistance of the Gram-negative bacterium <em>Pseudomonas aeruginosa</em> and its ability to form biofilm through the Quorum Sensing (QS) mechanism are important challenges in the control of infections caused by this pathogen. The extract of <em>Myrtus communis</em> (myrtle) showed strong anti-QS effect on <em>C</em><em>hromobacterium</em><em>. violaceum</em> 6267 by inhibiting 80 % of the production of violacein pigment at a sub-MIC concentration of 1/8 (31.25 μg/mL). In addition, the extract exhibited an inhibitory effect on virulence factors of <em>P. aeruginosa</em> PAO1 at half MIC (125 μg/mL), significantly reducing the formation of biofilms (72.02 %), the swarming activity (75 %), and the production of protease (61.83 %) and pyocyanin (97 %). The active fraction also downregulated the expression of selected regulatory genes involved in the biofilm formation and QS in the <em>P. aeruginosa</em> PAO1 strain. These genes included the autoinducer synthase genes (<em>lasI</em> and <em>rhlI</em>), the genes involved in the expression of their corresponding receptors (<em>lasR</em> and <em>rhlR</em>), and the <em>pqsA</em> genes. The analysis of the active fraction by HPLC/UV/MS and NMR allowed the identification of three phenolic compounds, 3,5-di-<em>O</em>-galloylquinic acid, myricetin 3-<em>O</em>-α-<span>l</span>-rhamnopyranoside (myricitrin), and myricetin 3-<em>O</em>-(2″-<em>O</em>-galloyl)-ß-<span>d</span>-galactopyranoside. <em>In silico</em> studies showed that 3,5-di-<em>O</em>-galloylquinic acid, with an affinity score of −9.20 kcal/mol, had the highest affinity to the active site of the CviR protein (3QP8), a QS receptor from <em>C. violaceum</em>. Additionally, myricetin 3-<em>O</em>-α-<span>l</span>-rhamnopyranoside (myricitrin) and myricetin 3-<em>O</em>-(2″-<em>O</em>-galloyl)-ß-<span>d</span>-galactopyranoside interact to a lesser extent with 3QP8. In conclusion, this study contributed significantly to the discovery of new QS inhibitors from <em>M. communis</em> leaves against resistant Gram-negative pathogens.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"8 ","pages":"Article 100205"},"PeriodicalIF":6.8,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000303/pdfft?md5=e1ab8e0c2e42512f1b9627761e5bcdba&pid=1-s2.0-S2590207524000303-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141412258","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}