1
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Wang S, Deng S, Wang Y. Theaflavin-3,3'-digallate effectively attenuates biofilm formation by Enterococcus faecalis via the targeting of specific quorum sensing pathways. Microb Pathog 2024; 193:106739. [PMID: 38857709 DOI: 10.1016/j.micpath.2024.106739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/28/2024] [Accepted: 06/07/2024] [Indexed: 06/12/2024]
Abstract
Enterococcus faecalis, an opportunistic pathogen responsible for nosocomial infections, exhibits increased pathogenicity via biofilm formation. Theaflavin-3,3'-digallate (TF3), a theaflavin extracted from black tea, exhibits potent antibacterial effects. In the present study, we investigated the inhibitory effect of TF3 on E. faecalis. Our results indicated that TF3 significantly inhibited E. faecalis ATCC 29212 biofilm formation. This observation was further confirmed via crystal violet staining, confocal laser scanning microscopy, and field emission-scanning electron microscopy. To disclose the underlying mechanisms, RNA-seq was applied. TF3 treatment significantly altered the transcriptomic profile of E. faecalis, as evidenced by identification of 248 differentially expressed genes (DEGs). Through functional annotation of these DEGs, several quorum-sensing pathways were found to be suppressed in TF3-treated cultures. Further, gene expression verification via real-time PCR confirmed the downregulation of gelE, sprE, and secY by TF3. These findings highlighted the ability of TF3 to impede E. faecalis biofilm formation, suggesting a novel preventive strategy against E. faecalis infections.
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Affiliation(s)
- Sa Wang
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, Zhejiang, China
| | - Shuli Deng
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, Zhejiang, China
| | - Ying Wang
- The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Key Laboratory of Oral Biomedical Research of Zhejiang Province, Zhejiang University School of Stomatology, Hangzhou, Zhejiang, China.
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2
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Sheriff EK, Salvato F, Andersen SE, Chatterjee A, Kleiner M, Duerkop BA. Enterococcal quorum-controlled protease alters phage infection. FEMS MICROBES 2024; 5:xtae022. [PMID: 39156124 PMCID: PMC11328733 DOI: 10.1093/femsmc/xtae022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Revised: 06/21/2024] [Accepted: 07/25/2024] [Indexed: 08/20/2024] Open
Abstract
Increased prevalence of multidrug-resistant bacterial infections has sparked interest in alternative antimicrobials, including bacteriophages (phages). Limited understanding of the phage infection process hampers our ability to utilize phages to their full therapeutic potential. To understand phage infection dynamics, we performed proteomics on Enterococcus faecalis infected with the phage VPE25. We discovered that numerous uncharacterized phage proteins are produced during phage infection of E. faecalis. Additionally, we identified hundreds of changes in bacterial protein abundances during infection. One such protein, enterococcal gelatinase (GelE), an fsr quorum-sensing-regulated protease involved in biofilm formation and virulence, was reduced during VPE25 infection. Plaque assays showed that mutation of either the quorum-sensing regulator fsrA or gelE resulted in plaques with a "halo" morphology and significantly larger diameters, suggesting decreased protection from phage infection. GelE-associated protection during phage infection is dependent on the putative murein hydrolase regulator LrgA and antiholin-like protein LrgB, whose expression have been shown to be regulated by GelE. Our work may be leveraged in the development of phage therapies that can modulate the production of GelE thereby altering biofilm formation and decreasing E. faecalis virulence.
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Affiliation(s)
- Emma K Sheriff
- Department of Immunology and Microbiology, School of Medicine, University of Colorado – Anschutz Medical Campus, 12800 E. 19th Ave., Aurora, CO 80045, United States
| | - Fernanda Salvato
- Department of Plant and Microbial Biology, North Carolina State University, 112 Derieux Pl., Raleigh, NC 27695, United States
| | - Shelby E Andersen
- Department of Immunology and Microbiology, School of Medicine, University of Colorado – Anschutz Medical Campus, 12800 E. 19th Ave., Aurora, CO 80045, United States
| | - Anushila Chatterjee
- Department of Immunology and Microbiology, School of Medicine, University of Colorado – Anschutz Medical Campus, 12800 E. 19th Ave., Aurora, CO 80045, United States
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, 112 Derieux Pl., Raleigh, NC 27695, United States
| | - Breck A Duerkop
- Department of Immunology and Microbiology, School of Medicine, University of Colorado – Anschutz Medical Campus, 12800 E. 19th Ave., Aurora, CO 80045, United States
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3
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Johnson AO, Shipman BM, Hunt BC, Learman BS, Brauer AL, Zhou SP, Hageman Blair R, De Nisco NJ, Armbruster CE. Function and contribution of two putative Enterococcus faecalis glycosaminoglycan degrading enzymes to bacteremia and catheter-associated urinary tract infection. Infect Immun 2024; 92:e0019924. [PMID: 38842305 PMCID: PMC11238560 DOI: 10.1128/iai.00199-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2024] [Accepted: 05/13/2024] [Indexed: 06/07/2024] Open
Abstract
Enterococcus faecalis is a common cause of healthcare-acquired bloodstream infections and catheter-associated urinary tract infections (CAUTIs) in both adults and children. Treatment of E. faecalis infection is frequently complicated by multi-drug resistance. Based on protein homology, E. faecalis encodes two putative hyaluronidases, EF3023 (HylA) and EF0818 (HylB). In other Gram-positive pathogens, hyaluronidases have been shown to contribute to tissue damage and immune evasion, but the function in E. faecalis has yet to be explored. Here, we show that both hylA and hylB contribute to E. faecalis pathogenesis. In a CAUTI model, ΔhylA exhibited defects in bladder colonization and dissemination to the bloodstream, and ΔhylB exhibited a defect in kidney colonization. Furthermore, a ΔhylAΔhylB double mutant exhibited a severe colonization defect in a model of bacteremia while the single mutants colonized to a similar level as the wild-type strain, suggesting potential functional redundancy within the bloodstream. We next examined enzymatic activity, and demonstrate that HylB is capable of digesting both hyaluronic acid (HA) and chondroitin sulfate in vitro, while HylA exhibits only a very modest activity against heparin. Importantly, HA degradation by HylB provided a modest increase in cell density during the stationary phase and also contributed to dampening of lipopolysaccharide-mediated NF-κB activation. Overall, these data demonstrate that glycosaminoglycan degradation is important for E. faecalis pathogenesis in the urinary tract and during bloodstream infection.
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Affiliation(s)
- Alexandra O Johnson
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Braden M Shipman
- Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Benjamin C Hunt
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Brian S Learman
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Aimee L Brauer
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Serena P Zhou
- Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Rachael Hageman Blair
- Department of Biostatistics, School of Public Health and Health Professions, State University of New York at Buffalo, Buffalo, New York, USA
| | - Nicole J De Nisco
- Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas, USA
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Chelsie E Armbruster
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
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4
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Tadesse BT, Svetlicic E, Zhao S, Berhane N, Jers C, Solem C, Mijakovic I. Bad to the bone? - Genomic analysis of Enterococcus isolates from diverse environments reveals that most are safe and display potential as food fermentation microorganisms. Microbiol Res 2024; 283:127702. [PMID: 38552381 DOI: 10.1016/j.micres.2024.127702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/09/2024] [Accepted: 03/20/2024] [Indexed: 04/17/2024]
Abstract
Enterococci comprise a group of lactic acid bacteria (LAB) with considerable potential to serve as food fermentation microorganisms. Unfortunately, enterococci have received a lot of negative attention, due to the occurrence of pathogenic and multidrug resistant strains. In this study, we used genomics to select safe candidates among the forty-four studied enterococcal isolates. The genomes of the forty-four strains were fully sequenced and assessed for presence of virulence and antibiotic resistance genes. Nineteen isolates belonging to the species Enterococcus lactis, Enterococcus faecium, Enterococcus durans, and Enterococcus thailandicus, were deemed safe from the genome analysis. The presence of secondary metabolite gene clusters for bacteriocins was assessed, and twelve candidates were found to secrete antimicrobial compounds effective against Listeria monocytogenes isolated from cheese and Staphylococcus aureus. Physiological characterization revealed nineteen industrial potentials; all strains grew well at 42 °C and acidified 1.5 hours faster than their mesophilic counterpart Lactococcus lactis, with which they share metabolism and flavor forming ability. We conclude that a large fraction of the examined enterococci were safe and could serve as excellent food fermentation microorganisms with inherent bioprotective abilities.
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Affiliation(s)
- Belay Tilahun Tadesse
- National Food Institute, Research Group for Microbial Biotechnology and Biorefining, Technical University of Denmark, Kgs Lyngby DK-2800, Denmark; Novo Nordisk Foundation Center for Biosustainability, Kongens Lyngby, Denmark
| | - Ema Svetlicic
- Novo Nordisk Foundation Center for Biosustainability, Kongens Lyngby, Denmark
| | - Shuangqing Zhao
- National Food Institute, Research Group for Microbial Biotechnology and Biorefining, Technical University of Denmark, Kgs Lyngby DK-2800, Denmark
| | - Nega Berhane
- Institute of Biotechnology, University of Gondar, Ethiopia
| | - Carsten Jers
- Novo Nordisk Foundation Center for Biosustainability, Kongens Lyngby, Denmark
| | - Christian Solem
- National Food Institute, Research Group for Microbial Biotechnology and Biorefining, Technical University of Denmark, Kgs Lyngby DK-2800, Denmark.
| | - Ivan Mijakovic
- Novo Nordisk Foundation Center for Biosustainability, Kongens Lyngby, Denmark; Systems and Synthetic Biology Division, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
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5
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Sangiorgio G, Calvo M, Migliorisi G, Campanile F, Stefani S. The Impact of Enterococcus spp. in the Immunocompromised Host: A Comprehensive Review. Pathogens 2024; 13:409. [PMID: 38787261 PMCID: PMC11124283 DOI: 10.3390/pathogens13050409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Revised: 05/05/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024] Open
Abstract
The immunocompromised host is usually vulnerable to infectious diseases due to broad-spectrum treatments and immunological dysregulation. The Enterococcus genus consists of normal gut commensals, which acquire a leading role in infective processes among individuals with compromised immune systems. These microorganisms may express a potential virulence and resistance spectrum, enabling their function as severe pathogens. The Enterococcus spp. infections in immunocompromised hosts appear to be difficult to resolve due to the immunological response impairment and the possibility of facing antimicrobial-resistant strains. As regards the related risk factors, several data demonstrated that prior antibiotic exposure, medical device insertion, prolonged hospitalization and surgical interventions may lead to Enterococcus overgrowth, antibiotic resistance and spread among critical healthcare settings. Herein, we present a comprehensive review of Enterococcus spp. in the immunocompromised host, summarizing the available knowledge about virulence factors, antimicrobial-resistance mechanisms and host-pathogen interaction. The review ultimately yearns for more substantial support to further investigations about enterococcal infections and immunocompromised host response.
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Affiliation(s)
- Giuseppe Sangiorgio
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy; (F.C.); (S.S.)
| | - Maddalena Calvo
- U.O.C. Laboratory Analysis Unit, University Hospital Policlinico-San Marco, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (G.M.)
| | - Giuseppe Migliorisi
- U.O.C. Laboratory Analysis Unit, University Hospital Policlinico-San Marco, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (G.M.)
| | - Floriana Campanile
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy; (F.C.); (S.S.)
| | - Stefania Stefani
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy; (F.C.); (S.S.)
- U.O.C. Laboratory Analysis Unit, University Hospital Policlinico-San Marco, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (G.M.)
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6
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Sheriff EK, Salvato F, Andersen SE, Chatterjee A, Kleiner M, Duerkop BA. Enterococcal quorum-controlled protease alters phage infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.10.593607. [PMID: 38766208 PMCID: PMC11100838 DOI: 10.1101/2024.05.10.593607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Increased prevalence of multidrug resistant bacterial infections has sparked interest in alternative antimicrobials, including bacteriophages (phages). Limited understanding of the phage infection process hampers our ability to utilize phages to their full therapeutic potential. To understand phage infection dynamics we performed proteomics on Enterococcus faecalis infected with the phage VPE25. We discovered numerous uncharacterized phage proteins are produced during phage infection of Enterococcus faecalis. Additionally, we identified hundreds of changes in bacterial protein abundances during infection. One such protein, enterococcal gelatinase (GelE), an fsr quorum sensing regulated protease involved in biofilm formation and virulence, was reduced during VPE25 infection. Plaque assays showed that mutation of either the fsrA or gelE resulted in plaques with a "halo" morphology and significantly larger diameters, suggesting decreased protection from phage infection. GelE-associated protection during phage infection is dependent on the murein hydrolase regulator LrgA and antiholin-like protein LrgB, whose expression have been shown to be regulated by GelE. Our work may be leveraged in the development of phage therapies that can modulate the production of GelE thereby altering biofilm formation and decreasing E. faecalis virulence.
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Affiliation(s)
- Emma K. Sheriff
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Fernanda Salvato
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695
| | - Shelby E. Andersen
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Anushila Chatterjee
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695
| | - Breck A. Duerkop
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
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7
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Johnson AO, Shipman BM, Hunt BC, Learman BS, Brauer AL, Zhou SP, Blair RH, De Nisco NJ, Armbruster CE. Function and contribution of two putative Enterococcus faecalis glycosaminoglycan degrading enzymes to bacteremia and catheter-associated urinary tract infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.08.593205. [PMID: 38766094 PMCID: PMC11100720 DOI: 10.1101/2024.05.08.593205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Enterococcus faecalis is a common cause of healthcare acquired bloodstream infections and catheter associated urinary tract infections (CAUTI) in both adults and children. Treatment of E. faecalis infection is frequently complicated by multi-drug resistance. Based on protein homology, E. faecalis encodes two putative hyaluronidases, EF3023 (HylA) and EF0818 (HylB). In other Gram-positive pathogens, hyaluronidases have been shown to contribute to tissue damage and immune evasion, but function in E. faecalis has yet to be explored. Here, we show that both hylA and hylB contribute to E. faecalis pathogenesis. In a CAUTI model, Δ hylA exhibited defects in bladder colonization and dissemination to the bloodstream, and Δ hylB exhibited a defect in kidney colonization. Furthermore, a Δ hylA Δ hylB double mutant exhibited a severe colonization defect in a model of bacteremia while the single mutants colonized to a similar level as the wild-type strain, suggesting potential functional redundancy within the bloodstream. We next examined enzymatic activity, and demonstrate that HylB is capable of digesting both HA and CS in vitro while HylA exhibits only a very modest activity against heparin. Importantly, HA degradation by HylB provided a modest increase in cell density during stationary phase and also contributed to dampening of LPS-mediated NF-Bκ activation. Overall, these data demonstrate that glycosaminoglycan degradation is important for E. faecalis pathogenesis in the urinary tract and during bloodstream infection.
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8
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Hembach N, Drechsel V, Sobol M, Kaster AK, Köhler HR, Triebskorn R, Schwartz T. Effect of glyphosate, its metabolite AMPA, and the glyphosate formulation Roundup ® on brown trout ( Salmo trutta f. fario) gut microbiome diversity. Front Microbiol 2024; 14:1271983. [PMID: 38298542 PMCID: PMC10829098 DOI: 10.3389/fmicb.2023.1271983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 12/26/2023] [Indexed: 02/02/2024] Open
Abstract
Glyphosate is used worldwide as a compound of pesticides and is detectable in many environmental compartments. It enters water bodies primarily through drift from agricultural areas so that aquatic organisms are exposed to this chemical, especially after rain events. Glyphosate is advertised and sold as a highly specific herbicide, which interacts with the EPSP synthase, an enzyme of the shikimate metabolism, resulting in inhibition of the synthesis of vital aromatic amino acids. However, not only plants but also bacteria can possess this enzyme so that influences of glyphosate on the microbiomes of exposed organisms cannot be excluded. Those influences may result in subtle and long-term effects, e.g., disturbance of the symbiotic interactions of bionts with microorganisms of their microbiomes. Mechanisms how the transformation product aminomethylphosphonic acid (AMPA) of glyphosate might interfere in this context have not understood so far. In the present study, molecular biological fingerprinting methods showed concentration-dependent effects of glyphosate and AMPA on fish microbiomes. In addition, age-dependent differences in the composition of the microbiomes regarding abundance and diversity were detected. Furthermore, the effect of exposure to glyphosate and AMPA was investigated for several fish pathogens of gut microbiomes in terms of their gene expression of virulence factors associated with pathogenicity. In vitro transcriptome analysis with the fish pathogen Yersinia ruckeri revealed that it is questionable whether the observed effect on the microbiome is caused by the intended mode of action of glyphosate, such as the inhibition of EPSP synthase activity.
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Affiliation(s)
- N. Hembach
- Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces, Karlsruhe, Germany
| | - V. Drechsel
- Institute of Evolution and Ecology, Animal Physiological Ecology, University of Tübingen, Tübingen, Germany
| | - M. Sobol
- Karlsruhe Institute of Technology (KIT), Institute for Biological Interfaces, Karlsruhe, Germany
| | - A.-K. Kaster
- Karlsruhe Institute of Technology (KIT), Institute for Biological Interfaces, Karlsruhe, Germany
| | - H.-R. Köhler
- Institute of Evolution and Ecology, Animal Physiological Ecology, University of Tübingen, Tübingen, Germany
| | - R. Triebskorn
- Institute of Evolution and Ecology, Animal Physiological Ecology, University of Tübingen, Tübingen, Germany
| | - T. Schwartz
- Karlsruhe Institute of Technology (KIT), Institute of Functional Interfaces, Karlsruhe, Germany
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9
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Yu L, Xu X, Chua WZ, Feng H, Ser Z, Shao K, Shi J, Wang Y, Li Z, Sobota RM, Sham LT, Luo M. Structural basis of peptide secretion for Quorum sensing by ComA. Nat Commun 2023; 14:7178. [PMID: 37935699 PMCID: PMC10630487 DOI: 10.1038/s41467-023-42852-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 10/23/2023] [Indexed: 11/09/2023] Open
Abstract
Quorum sensing (QS) is a crucial regulatory mechanism controlling bacterial signalling and holds promise for novel therapies against antimicrobial resistance. In Gram-positive bacteria, such as Streptococcus pneumoniae, ComA is a conserved efflux pump responsible for the maturation and secretion of peptide signals, including the competence-stimulating peptide (CSP), yet its structure and function remain unclear. Here, we functionally characterize ComA as an ABC transporter with high ATP affinity and determined its cryo-EM structures in the presence or absence of CSP or nucleotides. Our findings reveal a network of strong electrostatic interactions unique to ComA at the intracellular gate, a putative binding pocket for two CSP molecules, and negatively charged residues facilitating CSP translocation. Mutations of these residues affect ComA's peptidase activity in-vitro and prevent CSP export in-vivo. We demonstrate that ATP-Mg2+ triggers the outward-facing conformation of ComA for CSP release, rather than ATP alone. Our study provides molecular insights into the QS signal peptide secretion, highlighting potential targets for QS-targeting drugs.
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Affiliation(s)
- Lin Yu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, 225001, Jiangsu, China
| | - Xin Xu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Wan-Zhen Chua
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore
| | - Hao Feng
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Zheng Ser
- Functional Proteomics Laboratory, SingMass National Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
| | - Kai Shao
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Jian Shi
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
- Center for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore
| | - Yumei Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing, 100190, China
| | - Zongli Li
- Harvard Cryo-EM Center for Structural Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Radoslaw M Sobota
- Functional Proteomics Laboratory, SingMass National Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore.
| | - Min Luo
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore.
- Center for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore.
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10
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Robertson EB, Willett JLE. Streptococcus mutans inhibits the growth of Enterococcus via the non-ribosomal cyclic peptide mutanobactin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557362. [PMID: 37745448 PMCID: PMC10515869 DOI: 10.1101/2023.09.12.557362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Enterococcus faecalis is a Gram-positive commensal bacterium in the gastrointestinal tract and an opportunistic pathogen. Enterococci are a leading cause of nosocomial infections, treatment of which is complicated by intrinsic and acquired antibiotic resistance mechanisms. Additionally, E. faecalis has been associated with various oral diseases, and it is frequently implicated in the failure of endodontic treatment. For establishment and persistence in a microbial community, E. faecalis must successfully compete against other bacteria. Streptococcal species play an important role in the establishment of the oral microbiome and co-exist with Enterococcus in the small intestine, yet the nature of interactions between E. faecalis and oral streptococci remains unclear. Here, we describe a mechanism by which Streptococcus mutans inhibits the growth of E. faecalis and other Gram-positive pathogens through the production of mutanobactin, a cyclic lipopeptide. Mutanobactin is produced by a polyketide synthase-nonribosomal peptide synthetase hybrid system encoded by the mub locus. Mutanobactin-producing S. mutans inhibits planktonic and biofilm growth of E. faecalis and is also active against other Enterococcus species and Staphylococcus aureus. Mutanobactin damages the cell envelope of E. faecalis, similar to other lipopeptide antibiotics like daptomycin. E. faecalis resistance to mutanobactin is mediated by the virulence factor gelatinase, a secreted metalloprotease. Our results highlight the anti-biofilm potential of the microbial natural product mutanobactin, provide insight into how E. faecalis interacts with other organisms in the human microbiome, and demonstrate the importance of studying E. faecalis dynamics within polymicrobial communities.
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Affiliation(s)
- Ethan B. Robertson
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455 USA
| | - Julia L. E. Willett
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455 USA
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11
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Șchiopu P, Toc DA, Colosi IA, Costache C, Ruospo G, Berar G, Gălbău ȘG, Ghilea AC, Botan A, Pană AG, Neculicioiu VS, Todea DA. An Overview of the Factors Involved in Biofilm Production by the Enterococcus Genus. Int J Mol Sci 2023; 24:11577. [PMID: 37511337 PMCID: PMC10380289 DOI: 10.3390/ijms241411577] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/08/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
Enterococcus species are known for their ability to form biofilms, which contributes to their survival in extreme environments and involvement in persistent bacterial infections, especially in the case of multi-drug-resistant strains. This review aims to provide a comprehensive understanding of the mechanisms underlying biofilm formation in clinically important species such as Enterococcus faecalis and the less studied but increasingly multi-drug-resistant Enterococcus faecium, and explores potential strategies for their eradication. Biofilm formation in Enterococcus involves a complex interplay of genes and virulence factors, including gelatinase, cytolysin, Secreted antigen A, pili, microbial surface components that recognize adhesive matrix molecules (MSCRAMMs), and DNA release. Quorum sensing, a process of intercellular communication, mediated by peptide pheromones such as Cob, Ccf, and Cpd, plays a crucial role in coordinating biofilm development by targeting gene expression and regulation. Additionally, the regulation of extracellular DNA (eDNA) release has emerged as a fundamental component in biofilm formation. In E. faecalis, the autolysin N-acetylglucosaminidase and proteases such as gelatinase and serin protease are key players in this process, influencing biofilm development and virulence. Targeting eDNA may offer a promising avenue for intervention in biofilm-producing E. faecalis infections. Overall, gaining insights into the intricate mechanisms of biofilm formation in Enterococcus may provide directions for anti-biofilm therapeutic research, with the purpose of reducing the burden of Enterococcus-associated infections.
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Affiliation(s)
- Pavel Șchiopu
- Department of Microbiology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
- Department of Pneumology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400332 Cluj-Napoca, Romania
| | - Dan Alexandru Toc
- Department of Microbiology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Ioana Alina Colosi
- Department of Microbiology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Carmen Costache
- Department of Microbiology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Giuseppe Ruospo
- Faculty of Medicine, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - George Berar
- Faculty of Medicine, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Ștefan-Gabriel Gălbău
- Faculty of Medicine, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Alexandra Cristina Ghilea
- Faculty of Medicine, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Alexandru Botan
- Faculty of Medicine, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Adrian-Gabriel Pană
- Department of Microbiology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Vlad Sever Neculicioiu
- Department of Microbiology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Doina Adina Todea
- Department of Pneumology, "Iuliu Hațieganu" University of Medicine and Pharmacy, 400332 Cluj-Napoca, Romania
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12
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Yazıcı BC, Bakhedda N, Akçelik N. Effect of nisin and p-coumaric acid on autoinducer-2 activity, biofilm formation, and sprE expression of Enterococcus faecalis. Braz J Microbiol 2023; 54:601-608. [PMID: 36930448 PMCID: PMC10234943 DOI: 10.1007/s42770-023-00946-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 03/02/2023] [Indexed: 03/18/2023] Open
Abstract
Quorum sensing (QS) is an inter- and intracellular communication mechanism that regulates gene expression in response to population size. Autoinducer-2 (AI-2) signaling is a QS signaling molecule common to both Gram-negative and Gram-positive bacteria. Enterococcus faecalis is one of the leading causes of nosocomial infections worldwide. There has been an increasing interest in controlling infectious diseases through targeting the QS mechanism using natural compounds. This study aimed to investigate the effect of nisin and p-coumaric acid (pCA), on biofilm formation and AI-2 signaling in E. faecalis. Their effect on the expression of the QS-regulated virulence encoding gene sprE was also investigated. Nisin exhibited a MIC ranging from 0.25 to 0.5 mg/mL, while the MIC of pCA was 1 mg/mL. The luminescence-based response of the reporter strain Vibrio harveyi BB170 was used to determine AI-2 activity in E. faecalis strains. Nisin was not effective in inhibiting AI-2 activity, while pCA reduced AI-2 activity by ≥ 60%. Moreover, pCA and nisin combination showed higher inhibitory effect on biofilm formation of E. faecalis, compared to the treatment of pCA or nisin alone. qRT-PCR analysis showed that nisin alone and the combination of nisin and pCA, at their MIC values, led to a 32.78- and 40.22-fold decrease in sprE gene expression, respectively, while pCA alone did not have a significant effect. Considering the demand to explore new therapeutic avenues for infectious bacteria, this study was the first to report that pCA can act like a quorum sensing inhibitor (QSI) against AI-2 signaling in E. faecalis.
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Affiliation(s)
| | | | - Nefise Akçelik
- Biotechnology Institute, Ankara University, Ankara, Turkey.
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13
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Carrasco Calzada F, Jairo Aguilera J, Moreno JE, Cuadros González J, Roca Biosca D, Prieto-Pérez L, Pérez-Tanoira R. Differences in Virulence Factors and Antimicrobial Susceptibility of Uropathogenic Enterococcus spp. Strains in a Rural Area of Uganda and a Spanish Secondary Hospital. Trop Med Infect Dis 2023; 8:tropicalmed8050282. [PMID: 37235330 DOI: 10.3390/tropicalmed8050282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/09/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
Enterococcus faecalis and Enterococcus faecium have become two of the most important agents of nosocomial diseases due to their constantly growing resistance. Enterococcal infections are associated with biofilms, which are intrinsically sensitive to antimicrobials. The main goal of this study was to compare and relate their capacity to form biofilm and their antimicrobial sensitivity, as well as their virulence factors and their implicated genes, of strains isolated from patients with urinary tract infection (UTI) in a rural hospital in Uganda and a secondary hospital in Spain. A prospective study was conducted with 104 strains of E. faecalis and E. faecium isolated from patients with suspected UTI and who presented leukocyturia at the Saint Joseph Kitgum hospital (Uganda) and at the Hospital Universitario Principe de Asturias (Spain). All microorganisms were identified in Spain by MALDI-TOF mass spectrometry. Antimicrobial susceptibility studies were carried out using the Vitek® 2 system (Biomériux, France). The biofilm formation capacity was studied by photospectrometry. Phenotypic and genotypic virulence factors were studied in all cases by PCR or expression techniques. In Uganda, we found a higher incidence of E. faecium (65.3%, n = 32), contrary to the situation found in Spain where most of the bacteria found belonged to E. faecalis (92.7%, n = 51). All E. faecalis strains were found to have very low levels of resistance to ampicillin, imipenem, and nitrofurantoin. However, E. faecium exhibited more than 25% resistance to these antibiotics. Although the esp gene has been shown in the results obtained to be an important initial agent in biofilm formation, we have also demonstrated in this study the intervention of other genes when esp is not present, such as the ace1 gene. No statistically significant relationships were found between the presence of agg and gelE genes and increased biofilm formation. The significant difference between the incidence of E. faecalis and E. faecium and biofilm formation, between samples from Spain and Uganda, shows us very different profiles between countries.
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Affiliation(s)
- Félix Carrasco Calzada
- Clinical Microbiology Department, Hospital Universitario Príncipe de Asturias, 28805 Alcalá de Henares, Spain
- Health Sciences Department, Faculty of Med, Universidad de Alcalá, 28805 Alcalá de Henares, Spain
| | - John Jairo Aguilera
- IIS-Fundación Jiménez Díaz, 28007 Madrid, Spain
- CIBERINFEC-CIBER de Enfermedades Infecciosas, Instituto de Salud Carlos III, 28222 Madrid, Spain
| | - Jaime Esteban Moreno
- IIS-Fundación Jiménez Díaz, 28007 Madrid, Spain
- CIBERINFEC-CIBER de Enfermedades Infecciosas, Instituto de Salud Carlos III, 28222 Madrid, Spain
| | - Juan Cuadros González
- Clinical Microbiology Department, Hospital Universitario Príncipe de Asturias, 28805 Alcalá de Henares, Spain
- Health Sciences Department, Faculty of Med, Universidad de Alcalá, 28805 Alcalá de Henares, Spain
- Máster Medicina Tropical y Salud Internacional, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - David Roca Biosca
- Máster Medicina Tropical y Salud Internacional, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Fundación El Alto, 12500 Vinaroz, Spain
| | - Laura Prieto-Pérez
- IIS-Fundación Jiménez Díaz, 28007 Madrid, Spain
- Máster Medicina Tropical y Salud Internacional, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Ramón Pérez-Tanoira
- Clinical Microbiology Department, Hospital Universitario Príncipe de Asturias, 28805 Alcalá de Henares, Spain
- Health Sciences Department, Faculty of Med, Universidad de Alcalá, 28805 Alcalá de Henares, Spain
- Máster Medicina Tropical y Salud Internacional, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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14
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Funsten MC, Yurkovetskiy LA, Kuznetsov A, Reiman D, Hansen CHF, Senter KI, Lee J, Ratiu J, Dahal-Koirala S, Antonopoulos DA, Dunny GM, Sollid LM, Serreze D, Khan AA, Chervonsky AV. Microbiota-dependent proteolysis of gluten subverts diet-mediated protection against type 1 diabetes. Cell Host Microbe 2023; 31:213-227.e9. [PMID: 36603588 PMCID: PMC9911364 DOI: 10.1016/j.chom.2022.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/02/2022] [Accepted: 12/08/2022] [Indexed: 01/06/2023]
Abstract
Diet and commensals can affect the development of autoimmune diseases like type 1 diabetes (T1D). However, whether dietary interventions are microbe-mediated was unclear. We found that a diet based on hydrolyzed casein (HC) as a protein source protects non-obese diabetic (NOD) mice in conventional and germ-free (GF) conditions via improvement in the physiology of insulin-producing cells to reduce autoimmune activation. The addition of gluten (a cereal protein complex associated with celiac disease) facilitates autoimmunity dependent on microbial proteolysis of gluten: T1D develops in GF animals monocolonized with Enterococcus faecalis harboring secreted gluten-digesting proteases but not in mice colonized with protease deficient bacteria. Gluten digestion by E. faecalis generates T cell-activating peptides and promotes innate immunity by enhancing macrophage reactivity to lipopolysaccharide (LPS). Gnotobiotic NOD Toll4-negative mice monocolonized with E. faecalis on an HC + gluten diet are resistant to T1D. These findings provide insights into strategies to develop dietary interventions to help protect humans against autoimmunity.
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Affiliation(s)
- Matthew C Funsten
- Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA; Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Leonid A Yurkovetskiy
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA; Committee on Microbiology, The University of Chicago, Chicago, IL 60637, USA
| | - Andrey Kuznetsov
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Derek Reiman
- Toyota Technological Institute at Chicago, Chicago, IL 60637, USA
| | - Camilla H F Hansen
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA; Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark
| | - Katharine I Senter
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Jean Lee
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA; Committee on Cancer Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Jeremy Ratiu
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Shiva Dahal-Koirala
- KG Jebsen Coeliac Disease Research Centre and Department of Immunology, University of Oslo and University of Oslo Hospital, 0372 Oslo, Norway
| | | | - Gary M Dunny
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Ludvig M Sollid
- KG Jebsen Coeliac Disease Research Centre and Department of Immunology, University of Oslo and University of Oslo Hospital, 0372 Oslo, Norway
| | | | - Aly A Khan
- Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA; Department of Pathology, The University of Chicago, Chicago, IL 60637, USA; Institute for Population and Precision Health, The University of Chicago, Chicago, IL 60637, USA; Department of Family Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Alexander V Chervonsky
- Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA; Department of Pathology, The University of Chicago, Chicago, IL 60637, USA; Committee on Microbiology, The University of Chicago, Chicago, IL 60637, USA.
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15
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McBrayer DN, Ghosh U, Lella M, Cameron CD, Tal-Gan Y. Peptoid-Peptide Hybrid Analogs of the Enterococcus faecalis Fsr Auto-Inducing Peptide (AIP) Reveal Crucial Structure-Activity Relationships. Chembiochem 2023; 24:e202200527. [PMID: 36376247 PMCID: PMC9812899 DOI: 10.1002/cbic.202200527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 11/12/2022] [Indexed: 11/16/2022]
Abstract
As multidrug-resistant bacteria become a more pressing risk to human health, alternate approaches to treating bacterial infections are being increasingly investigated. Enterococcus faecalis is an opportunistic pathogen responsible for a large percentage of secondary enterococci infections. Its pathogenicity has been shown to be largely dependent on a cell-density communication mechanism, termed quorum sensing. In this study, we conducted a systematic investigation of the lactone-containing macrocyclic signaling peptide used by E. faecalis for Fsr-mediated communication, termed gelatinase biosynthesis activating pheromone (GBAP). Specifically, through a combination of the on-resin sub-monomer and solution phase peptoid building block synthesis approaches, we successfully synthesized a library of peptoid-peptide hybrid analogs of GBAP and determined the biological effects associated with the introduction of the peptoid (N-alkyl glycine derivative) modifications. Within the macrocycle region of the peptide, as have been seen with other modifications, the F7 site was unusually tolerant toward peptoid modification, compared with other macrocyclic sites. Interestingly, within the exocyclic tail, peptoid modification at the N2 site completely abolished activity, a first for a single tail modification.
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Affiliation(s)
- Dominic N. McBrayer
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV, 89557, USA
| | - Uttam Ghosh
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV, 89557, USA
| | - Muralikrishna Lella
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV, 89557, USA
| | - Crissey D. Cameron
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV, 89557, USA
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV, 89557, USA
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16
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Ongpipattanakul C, Desormeaux EK, DiCaprio A, van der Donk WA, Mitchell DA, Nair SK. Mechanism of Action of Ribosomally Synthesized and Post-Translationally Modified Peptides. Chem Rev 2022; 122:14722-14814. [PMID: 36049139 PMCID: PMC9897510 DOI: 10.1021/acs.chemrev.2c00210] [Citation(s) in RCA: 66] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a natural product class that has undergone significant expansion due to the rapid growth in genome sequencing data and recognition that they are made by biosynthetic pathways that share many characteristic features. Their mode of actions cover a wide range of biological processes and include binding to membranes, receptors, enzymes, lipids, RNA, and metals as well as use as cofactors and signaling molecules. This review covers the currently known modes of action (MOA) of RiPPs. In turn, the mechanisms by which these molecules interact with their natural targets provide a rich set of molecular paradigms that can be used for the design or evolution of new or improved activities given the relative ease of engineering RiPPs. In this review, coverage is limited to RiPPs originating from bacteria.
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Affiliation(s)
- Chayanid Ongpipattanakul
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Emily K. Desormeaux
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Adam DiCaprio
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Wilfred A. van der Donk
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Departments of Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA
| | - Douglas A. Mitchell
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Microbiology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Departments of Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Departments of Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA
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17
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Venkateswaran P, Lakshmanan PM, Muthukrishnan S, Bhagavathi H, Vasudevan S, Neelakantan P, Solomon AP. Hidden agenda of Enterococcus faecalis lifestyle transition: planktonic to sessile state. Future Microbiol 2022; 17:1051-1069. [PMID: 35899477 DOI: 10.2217/fmb-2021-0212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Enterococcus faecalis, a human gastrointestinal tract commensal, is known to cause nosocomial infections. Interestingly, the pathogen's host colonization and persistent infections are possibly linked to its lifestyle changes from planktonic to sessile state. Also, the multidrug resistance and survival fitness acquired in the sessile stage of E. faecalis has challenged treatment regimes. This situation exists because of the critical role played by several root genes and their molecular branches, which are part of quorum sensing, aggregation substance, surface adhesions, stress-related response and sex pheromones in the sessile state. It is therefore imperative to decode the hidden agenda of E. faecalis and understand the significant factors influencing biofilm formation. This would, in turn, augment the development of novel strategies to tackle E. faecalis infections.
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Affiliation(s)
- Parvathy Venkateswaran
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur, 613401, India
| | - Priya M Lakshmanan
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur, 613401, India
| | - Sudhiksha Muthukrishnan
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur, 613401, India
| | - Hema Bhagavathi
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur, 613401, India
| | - Sahana Vasudevan
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur, 613401, India
| | | | - Adline P Solomon
- Quorum Sensing Laboratory, Centre for Research in Infectious Diseases (CRID), School of Chemical & Biotechnology, SASTRA Deemed to be University, Thanjavur, 613401, India
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18
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Enterococcus Virulence and Resistant Traits Associated with Its Permanence in the Hospital Environment. Antibiotics (Basel) 2022; 11:antibiotics11070857. [PMID: 35884110 PMCID: PMC9311936 DOI: 10.3390/antibiotics11070857] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 11/17/2022] Open
Abstract
Enterococcus are opportunistic pathogens that have been gaining importance in the clinical setting, especially in terms of hospital-acquired infections. This problem has mainly been associated with the fact that these bacteria are able to present intrinsic and extrinsic resistance to different classes of antibiotics, with a great deal of importance being attributed to vancomycin-resistant enterococci. However, other aspects, such as the expression of different virulence factors including biofilm-forming ability, and its capacity of trading genetic information, makes this bacterial genus more capable of surviving harsh environmental conditions. All these characteristics, associated with some reports of decreased susceptibility to some biocides, all described in this literary review, allow enterococci to present a longer survival ability in the hospital environment, consequently giving them more opportunities to disseminate in these settings and be responsible for difficult-to-treat infections.
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19
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Kadhim E, Amin B, Amin B. Anti-Quorum Sensing Effect of Salvadora Persica Against Enterococcus faecalis (ATCC 29212). Open Dent J 2022. [DOI: 10.2174/18742106-v16-e2204280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Introduction:
Quorum Sensing (QS) is a mechanism many bacteria use to manage their cooperative activities and physiological functions. The Fsr system in Enterococcus faecalis (ATCC 29,212) is an example of quorum sensing with a cell density-dependent two-component regulatory system mechanism. Several publications have shown that the Fsr system and proteases independently contribute to E. faecalis pathogenicity in various infection models.
Objectives:
There is currently no published research to determine the exact molecular ability of Salvadora persica on quorum-sensing genes. Therefore, this study aimed to determine the plant extracts that inhibit the expression of the quorum-sensing gene (FsrC).
Methods:
Different fractions of Salvadora persica were obtained using different solvents, including standard hexane, chloroform, ethyl acetate, n-butanol, ethyl alcohol, and water which are expressed as fractions 1,2,3,4,5 and 6, respectively. Antibacterial activity assay of different plant extracts (S. persica) was determined by minimum inhibitory concentration (MIC). Finally, the relative expression of the quorum-sensing (QS) gene was evaluated using a One-step quantitative RT-PCR PrimeScript™ RT-PCR Kit.
Results:
All fractions of S. persica showed antimicrobial activity. However, ethyl acetate- S. persica inhibited the growth of E. faecalis (ATCC 29,212) at the lowest concentration, which was 20mg/ml and the highest concentration inhibited the growth of E. faecalis (ATCC 29,212) was 60mg/ml (chloroform- S. persica). Furthermore, the highest change fold value of (4.99) was recorded in treated E. faecalis (ATCC 29,212) with fraction 1 (hexane).
Conclusion:
Overall, S. persica showed antimicrobial activity against E. faecalis (ATCC 29,212). However, more studies are required to investigate the effect of different plant extracts on quorum-sensing genes of Enterococcus faecalis.
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20
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Kaushik S, Yadav J, Das S, Karthikeyan D, Chug R, Jyoti A, Srivastava VK, Jain A, Kumar S, Sharma V. Identification of Protein Drug Targets of Biofilm Formation and Quorum
Sensing in Multidrug Resistant Enterococcus faecalis. Curr Protein Pept Sci 2022; 23:248-263. [DOI: 10.2174/1389203723666220526155644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/16/2022] [Accepted: 04/06/2022] [Indexed: 11/22/2022]
Abstract
Abstract:
Enterococcus faecalis (E. faecalis) is an opportunistic multidrug-resistant (MDR) pathogen
found in the guts of humans and farmed animals. Due to the occurrence of (MDR) strain there is an
urgent need to look for an alternative treatment approach. E. faecalis is a Gram-positive bacterium,
which is among the most prevalent multidrug resistant hospital pathogens. Its ability to develop quorum
sensing (QS) mediated biofilm formation further exacerbates the pathogenicity and triggers lifethreatening
infections. Therefore, developing a suitable remedy for curing E. faecalis mediated enterococcal
infections is an arduous task. Several putative virulence factors and proteins are involved in the
development of biofilms in E. faecalis. Such proteins often play important roles in virulence, disease,
and colonization by pathogens. The elucidation of the structure-function relationship of such protein
drug targets and the interacting compounds could provide an attractive paradigm towards developing
structure-based drugs against E. faecalis. This review provides a comprehensive overview of the current
status, enigmas that warrant further studies, and the prospects toward alleviating the antibiotic resistance
in E. faecalis. Specifically, the role of biofilm and quorum sensing (QS) in the emergence of
MDR strains had been elaborated along with the importance of the protein drug targets involved in both
the processes.
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Affiliation(s)
- Sanket Kaushik
- Amity Institute of Biotechnology, Amity University Rajasthan, Jaipur, India
| | - Jyoti Yadav
- Amity Institute of Biotechnology, Amity University Rajasthan, Jaipur, India
| | - Satyajeet Das
- Amity Institute of Biotechnology, Amity University Rajasthan, Jaipur, India
- Structural Biology Lab, CSIR-Institute of Microbial Technology, Chandigarh, India
| | | | - Ravneet Chug
- Amity Institute of Biotechnology, Amity University Rajasthan, Jaipur, India
| | - Anupam Jyoti
- Department of Biotechnology, University Institute of Biotechnology,
Chandigarh University, Chandigarh, India
| | | | - Ajay Jain
- Amity Institute of Biotechnology, Amity University Rajasthan, Jaipur, India
| | - Sanjit Kumar
- Centre for Bioseparation Technology, VIT
University, Vellore-632014, Tamil Nadu, India
| | - Vinay Sharma
- Amity Institute of Biotechnology, Amity University Rajasthan, Jaipur, India
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21
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Ali IAA, Lévesque CM, Neelakantan P. Fsr quorum sensing system modulates the temporal development of Enterococcus faecalis biofilm matrix. Mol Oral Microbiol 2021; 37:22-30. [PMID: 34862746 DOI: 10.1111/omi.12357] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/13/2021] [Accepted: 11/30/2021] [Indexed: 11/27/2022]
Abstract
Quorum sensing (QS) is a cell-to-cell communication process that regulates major pathogenic attributes in bacteria including biofilm formation, secretion of virulence factors, and antimicrobial resistance. The two-component Fsr-QS system of the nosocomial pathogen Enterococcus faecalis controls the production of extracellular gelatinase that contributes to biofilm development by enhancing the release of nucleic acids into the biofilm matrix. However, the contribution of this system to the deposition of other biofilm matrix components such as polysaccharides and proteins remains unknown. Using wild type and mutant strains, we discovered that biofilm formation was attenuated by inactivation of the Fsr system or its downstream gelatinase production. Inactivation of the Fsr system caused a modest, yet significant reduction in biofilm metabolic activity without affecting cell counts. Inactivation of the QS-signal sensor FsrC and response regulator FsrA resulted in decreased extracellular polysaccharides and proteins in biofilms in a temporal manner. Irrespective of biofilm age, eDNA levels were reduced in the gelatinase mutant strain. Our results collectively suggest that the Fsr system contributes to the temporal deposition of polysaccharides and proteins into the extracellular polymeric matrix (EPS) of E. faecalis biofilm, without affecting bacterial viability. This understanding of the role of the Fsr-QS system in biofilm development may reveal a novel target to develop effective antibiofilm agents to tackle E. faecalis-mediated infections such as in dental root canals, heart valves, and surgical sites.
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Affiliation(s)
- Islam A A Ali
- Faculty of Dentistry, The University of Hong Kong, Sai Ying Pun, Hong Kong SAR, China
| | | | - Prasanna Neelakantan
- Faculty of Dentistry, The University of Hong Kong, Sai Ying Pun, Hong Kong SAR, China
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Piewngam P, Chiou J, Ling J, Liu R, Pupa P, Zheng Y, Otto M. Enterococcal bacteremia in mice is prevented by oral administration of probiotic Bacillus spores. Sci Transl Med 2021; 13:eabf4692. [PMID: 34818053 PMCID: PMC11097119 DOI: 10.1126/scitranslmed.abf4692] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Whether and how probiotics promote human health is a controversial issue. Their claimed benefit for counteracting gastrointestinal infection is linked predominantly to reducing pathogen abundance within the intestinal microbiota. Less understood mechanistically is the reported value that probiotics could have in reducing systemic infections. Enterococcus faecalis is an opportunistic pathogen that causes systemic infection after translocation through the intestinal epithelium, particularly in hospitalized and immune-depleted patients receiving antibiotic therapy. In this study, we used an E. faecalis mouse infection model with wild-type and isogenic mutant strains deficient in genes of the E. faecalis Fsr (fecal streptococci regulator) quorum-sensing system. We show that E. faecalis translocation from the mouse gut into the blood is mediated by the Fsr quorum-sensing system through production of the protease GelE, which compromises intestinal epithelium integrity. Furthermore, we demonstrate that orally administered probiotic Bacillus subtilis spores blocked E. faecalis translocation from the gut to the bloodstream and subsequent systemic infection in mice by inhibiting Fsr activity. These findings demonstrate that a key aspect of Enterococcus pathogenesis is controlled by quorum sensing, which can be targeted with probiotic Bacillus spores.
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Affiliation(s)
- Pipat Piewngam
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Janice Chiou
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Joie Ling
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Ryan Liu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Pawiya Pupa
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Yue Zheng
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, MD 20814, USA
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Bio-Mechanism of Catechin as Pheromone Signal Inhibitor: Prediction of Antibacterial Agent Action Mode by In Vitro and In Silico Study. Molecules 2021; 26:molecules26216381. [PMID: 34770790 PMCID: PMC8587927 DOI: 10.3390/molecules26216381] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/13/2021] [Accepted: 10/19/2021] [Indexed: 11/24/2022] Open
Abstract
The utilization of medicinal plants has long been explored for the discovery of antibacterial agents and the most effective mechanisms or new targets that can prevent and control the spread of antibiotic resistance. One kind of bacterial cell wall inhibition is the inactivation of the MurA enzyme that contributes to the formation of peptidoglycan. Another approach is to interfere with the cell–cell communication of bacteria called the Quorum sensing (QS) system. The blocking of auto-inducer such as gelatinase biosynthesis-activating pheromone (GBAP) can also suppress the virulence factors of gelatinase and serine protease. This research, in particular, aims to analyze lead compounds as antibacterial and anti-QS agents from Gambir (Uncaria gambir Roxburgh) through protein inhibition by in silico study. Antibacterial agents were isolated by bioactivity-guided isolation using a combination of chromatographic methods, and their chemical structures were determined by spectroscopic analysis methods. The in vitro antibacterial activity was evaluated by disc diffusion methods to determine inhibitory values. Meanwhile, in the in silico analysis, the compound of Uncaria gambir was used as ligand and compared with fosfomycin, ambuic acid, quercetin, and taxifolin as the standard ligand. These ligands were attached to MurA, GBAP, gelatinase, and serine proteases using Autodock Vina in PyRx 0.8 followed by PYMOL for combining the ligand conformation and proteins. plus programs to explore the complex, and visualized by Discovery Studio 2020 Client program. The antibacterial agent was identified as catechin that showed inhibitory activity against Enterococcus faecalis ATCC 29212 with inhibition zones of 11.70 mm at 10%, together with MIC and MBC values of 0.63 and 1.25 μg/mL, respectively. In the in silico study, the molecular interaction of catechin with MurA, GBAP, and gelatinase proteins showed good binding energy compared with two positive controls, namely fosfomycin and ambuic acid. It is better to use catechin–MurA (−8.5 Kcal/mol) and catechin–gelatinase (−7.8 Kcal/mol), as they have binding energies which are not marginally different from quercetin and taxifolin. On the other hand, the binding energy of serine protease is lower than quercetin, taxifolin, and ambuic acid. Based on the data, catechin has potency as an antibacterial through the inhibition of GBAP proteins, gelatinase, and serine protease that play a role in the QS system. This is the first discovery of the potential of catechin as an alternative antibacterial agent with an effective mechanism to prevent and control oral disease affected by antibiotic resistance.
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Ma P, Phillips-Jones MK. Membrane Sensor Histidine Kinases: Insights from Structural, Ligand and Inhibitor Studies of Full-Length Proteins and Signalling Domains for Antibiotic Discovery. Molecules 2021; 26:molecules26165110. [PMID: 34443697 PMCID: PMC8399564 DOI: 10.3390/molecules26165110] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/02/2021] [Accepted: 08/19/2021] [Indexed: 12/19/2022] Open
Abstract
There is an urgent need to find new antibacterial agents to combat bacterial infections, including agents that inhibit novel, hitherto unexploited targets in bacterial cells. Amongst novel targets are two-component signal transduction systems (TCSs) which are the main mechanism by which bacteria sense and respond to environmental changes. TCSs typically comprise a membrane-embedded sensory protein (the sensor histidine kinase, SHK) and a partner response regulator protein. Amongst promising targets within SHKs are those involved in environmental signal detection (useful for targeting specific SHKs) and the common themes of signal transmission across the membrane and propagation to catalytic domains (for targeting multiple SHKs). However, the nature of environmental signals for the vast majority of SHKs is still lacking, and there is a paucity of structural information based on full-length membrane-bound SHKs with and without ligand. Reasons for this lack of knowledge lie in the technical challenges associated with investigations of these relatively hydrophobic membrane proteins and the inherent flexibility of these multidomain proteins that reduces the chances of successful crystallisation for structural determination by X-ray crystallography. However, in recent years there has been an explosion of information published on (a) methodology for producing active forms of full-length detergent-, liposome- and nanodisc-solubilised membrane SHKs and their use in structural studies and identification of signalling ligands and inhibitors; and (b) mechanisms of signal sensing and transduction across the membrane obtained using sensory and transmembrane domains in isolation, which reveal some commonalities as well as unique features. Here we review the most recent advances in these areas and highlight those of potential use in future strategies for antibiotic discovery. This Review is part of a Special Issue entitled “Interactions of Bacterial Molecules with Their Ligands and Other Chemical Agents” edited by Mary K. Phillips-Jones.
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Affiliation(s)
- Pikyee Ma
- Laboratory of Biomolecular Research, Paul Scherrer Institute, CH-5232 Villigen, Switzerland;
| | - Mary K. Phillips-Jones
- National Centre for Macromolecular Hydrodynamics, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
- Correspondence:
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Trans-Cinnamaldehyde Attenuates Enterococcus faecalis Virulence and Inhibits Biofilm Formation. Antibiotics (Basel) 2021; 10:antibiotics10060702. [PMID: 34208134 PMCID: PMC8230787 DOI: 10.3390/antibiotics10060702] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/09/2021] [Accepted: 06/09/2021] [Indexed: 11/21/2022] Open
Abstract
Enterococcus faecalis as an important nosocomial pathogen is critically implicated in the pathogenesis of endocarditis, urinary tract, and persistent root canal infections. Its major virulence attributes (biofilm formation, production of proteases, and hemolytic toxins) enable it to cause extensive host tissue damage. With the alarming increase in enterococcal resistance to antibiotics, novel therapeutics are required to inhibit E. faecalis biofilm formation and virulence. Trans-cinnamaldehyde (TC), the main phytochemical in cinnamon essential oils, has demonstrated promising activity against a wide range of pathogens. Here, we comprehensively investigated the effect of TC on planktonic growth, biofilm formation, proteolytic and hemolytic activities, as well as gene regulation in E. faecalis. Our findings revealed that sub-inhibitory concentrations of TC reduced biofilm formation, biofilm exopolysaccharides, as well as its proteolytic and hemolytic activities. Mechanistic studies revealed significant downregulation of the quorum sensing fsr locus and downstream gelE, which are major virulence regulators in E. faecalis. Taken together, our study highlights the potential of TC to inhibit E. faecalis biofilm formation and its virulence.
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Bin-Asif H, Abid Ali S. The Genus Enterococcus and Its Associated Virulent Factors. Microorganisms 2020. [DOI: 10.5772/intechopen.89083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Piewngam P, Chiou J, Chatterjee P, Otto M. Alternative approaches to treat bacterial infections: targeting quorum-sensing. Expert Rev Anti Infect Ther 2020; 18:499-510. [PMID: 32243194 PMCID: PMC11032741 DOI: 10.1080/14787210.2020.1750951] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 03/31/2020] [Indexed: 12/22/2022]
Abstract
Introduction: The emergence of multi- and pan-drug-resistant bacteria represents a global crisis that calls for the development of alternative anti-infective strategies. These comprise anti-virulence approaches, which target pathogenicity without exerting a bacteriostatic or bactericidal effect and are claimed to reduce the development of resistance. Because in many pathogens, quorum-sensing (QS) systems control the expression of virulence factors, interference with QS, or quorum-quenching, is often proposed as a strategy with a broad anti-virulence effect.Areas covered: We discuss the role and regulatory targets of QS control in selected Gram-positive and Gram-negative bacteria, focusing on those with clinical importance and QS control of virulence. We present the components of QS systems that form possible targets for the development of anti-virulence drugs and discuss recent research on quorum-quenching approaches to control bacterial infection.Expert opinion: While there has been extensive research on QS systems and quorum-quenching approaches, there is a paucity of in-vivo research using adequate animal models to substantiate applicability. In-vivo research on QS blockers needs to be intensified and optimized to use clinically relevant setups, in order to underscore that such drugs can be used effectively to overcome problems associated with the treatment of severe infections by antibiotic-resistant pathogens.
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Affiliation(s)
- Pipat Piewngam
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, Maryland 20814, USA
| | - Janice Chiou
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, Maryland 20814, USA
| | - Priyanka Chatterjee
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, Maryland 20814, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, U.S. National Institutes of Health, 50 South Drive, Bethesda, Maryland 20814, USA
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Christley S, Shogan B, Levine Z, Koo H, Guyton K, Owens S, Gilbert J, Zaborina O, Alverdy JC. Comparative genetics of Enterococcus faecalis intestinal tissue isolates before and after surgery in a rat model of colon anastomosis. PLoS One 2020; 15:e0232165. [PMID: 32343730 PMCID: PMC7188289 DOI: 10.1371/journal.pone.0232165] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 04/08/2020] [Indexed: 12/17/2022] Open
Abstract
We have recently demonstrated that collagenolytic Enterococcus faecalis plays a key and causative role in the pathogenesis of anastomotic leak, an uncommon but potentially lethal complication characterized by disruption of the intestinal wound following segmental removal of the colon (resection) and its reconnection (anastomosis). Here we hypothesized that comparative genetic analysis of E. faecalis isolates present at the anastomotic wound site before and after surgery would shed insight into the mechanisms by which collagenolytic strains are selected for and predominate at sites of anastomotic disruption. Whole genome optical mapping of four pairs of isolates from rat colonic tissue obtained following surgical resection (herein named “pre-op” isolates) and then 6 days later from the anastomotic site (herein named “post-op” isolates) demonstrated that the isolates with higher collagenolytic activity formed a distinct cluster. In order to perform analysis at a deeper level, a single pair of E. faecalis isolates (16A pre-op and 16A post-op) was selected for whole genome sequencing and assembled using a hybrid assembly algorithm. Comparative genomics demonstrated absence of multiple gene clusters, notably a pathogenicity island in the post-op isolate. No differences were found in the fsr-gelE-sprE genes (EF1817-1822) responsible for regulation and production of collagenolytic activity. Analysis of unique genes among the 16A pre-op and post-op isolates revealed the predominance of transporter systems-related genes in the pre-op isolate and phage-related and hydrolytic enzyme-encoding genes in the post-op isolate. Despite genetic differences observed between pre-op and post-op isolates, the precise genetic determinants responsible for their differential expression of collagenolytic activity remains unknown.
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Affiliation(s)
- Scott Christley
- Department of Surgery, University of Chicago, Chicago, IL, United States of America
| | - Benjamin Shogan
- Department of Surgery, University of Chicago, Chicago, IL, United States of America
| | - Zoe Levine
- Department of Surgery, University of Chicago, Chicago, IL, United States of America
| | - Hyun Koo
- Department of Surgery, University of Chicago, Chicago, IL, United States of America
| | - Kristina Guyton
- Department of Surgery, University of Chicago, Chicago, IL, United States of America
| | - Sarah Owens
- Argonne National Laboratory, Argonne, IL, United States of America
| | - Jack Gilbert
- Department of Surgery, University of Chicago, Chicago, IL, United States of America
- Argonne National Laboratory, Argonne, IL, United States of America
| | - Olga Zaborina
- Department of Surgery, University of Chicago, Chicago, IL, United States of America
| | - John C. Alverdy
- Department of Surgery, University of Chicago, Chicago, IL, United States of America
- * E-mail:
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Abstract
We lack fundamental understanding of how phage infection influences bacterial gene expression and, consequently, how bacterial responses to phage infection affect the assembly of polymicrobial communities. Using parallel genomic approaches, we have discovered novel transcriptional regulators and metabolic genes that influence phage infection. The integration of whole-genome transcriptomic profiling during phage infection has revealed the differential regulation of genes important for group behaviors and polymicrobial interactions. Our work suggests that therapeutic phages could more broadly influence bacterial community composition outside their intended host targets. Bacteriophages (phages) have been proposed as alternative therapeutics for the treatment of multidrug-resistant bacterial infections. However, there are major gaps in our understanding of the molecular events in bacterial cells that control how bacteria respond to phage predation. Using the model organism Enterococcus faecalis, we used two distinct genomic approaches, namely, transposon library screening and RNA sequencing, to investigate the interaction of E. faecalis with a virulent phage. We discovered that a transcription factor encoding a LytR family response regulator controls the expression of enterococcal polysaccharide antigen (epa) genes that are involved in phage infection and bacterial fitness. In addition, we discovered that DNA mismatch repair mutants rapidly evolve phage adsorption deficiencies, underpinning a molecular basis for epa mutation during phage infection. Transcriptomic profiling of phage-infected E. faecalis revealed broad transcriptional changes influencing viral replication and progeny burst size. We also demonstrate that phage infection alters the expression of bacterial genes associated with intra- and interbacterial interactions, including genes involved in quorum sensing and polymicrobial competition. Together, our results suggest that phage predation has the potential to influence complex microbial behavior and may dictate how bacteria respond to external environmental stimuli. These responses could have collateral effects (positive or negative) on microbial communities, such as the host microbiota, during phage therapy.
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Potential Control of Listeria monocytogenes by Bacteriocinogenic Enterococcus hirae ST57ACC and Pediococcus pentosaceus ST65ACC Strains Isolated From Artisanal Cheese. Probiotics Antimicrob Proteins 2020; 11:696-704. [PMID: 30069686 DOI: 10.1007/s12602-018-9449-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Bacteriocinogenic Enterococcus hirae ST57ACC and Pediococcus pentosaceus ST65ACC strains, previously isolated from artisanal cheese, were evaluated for their safety with the aim to determine whether they could be used as beneficial strains, especially in the control of Listeria monocytogenes. Both isolates survived simulated gastrointestinal conditions and showed high levels of auto- and co-aggregation with L. monocytogenes, although the hydrophobicity of cells varied. Using the agar-spot test with 33 commercial drugs from different groups, only anti-inflammatory drugs and drugs containing loratadine and propranolol hydrochloride were able to affect the growth of the tested strains. Both strains were resistant to 3 out of 11 antibiotics tested by the disc diffusion method, and low frequencies of antibiotic resistance-encoding genes were observed by PCR analysis. Tested strains neither presented biogenic amine-related genes nor produced these substances. Aside from some antibiotic resistance characteristics, the tested strains were considered safe as they lack other virulence-related genes. E. hirae ST57ACC and P. pentosaceus ST65ACC both presented beneficial properties, particularly their ability to survive gastrointestinal conditions and to aggregate with L. monocytogenes, which can facilitate the elimination of this pathogen. Further studies should be conducted to better understand these interactions.
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Tan CAZ, Antypas H, Kline KA. Overcoming the challenge of establishing biofilms in vivo: a roadmap for Enterococci. Curr Opin Microbiol 2020; 53:9-18. [PMID: 32062025 DOI: 10.1016/j.mib.2020.01.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/10/2020] [Accepted: 01/15/2020] [Indexed: 12/28/2022]
Abstract
Enterococcus faecalis forms single and mixed-species biofilms on both tissue and medical devices in the host, often under exposure to fluid flow, giving rise to infections that are recalcitrant to treatment. The factors that drive enterococcal biofilm formation in the host, however, remain unclear. Recent reports in other pathogens show how surface sensing by bacteria can trigger the transition from planktonic to sessile lifestyle. Fluid flow can enhance initial adhesion, but also influence quorum sensing. Biofilm-specific factors, as well as biofilm size and extracellular polymeric substances, can compromise opsonization and phagocytosis. Bacterial interspecies synergy can create favorable conditions in the host for biofilm formation. Through these concepts, we define the knowledge gaps in understanding host-associated E. faecalis biofilm formation and propose a roadmap for future investigations.
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Affiliation(s)
- Casandra Ai Zhu Tan
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Haris Antypas
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore.
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Yang Y, Lin J, Harrington A, Cornilescu G, Lau GW, Tal-Gan Y. Designing cyclic competence-stimulating peptide (CSP) analogs with pan-group quorum-sensing inhibition activity in Streptococcus pneumoniae. Proc Natl Acad Sci U S A 2020; 117:1689-1699. [PMID: 31915298 PMCID: PMC6983377 DOI: 10.1073/pnas.1915812117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Streptococcus pneumoniae is an opportunistic human pathogen that utilizes the competence regulon, a quorum-sensing circuitry, to acquire antibiotic resistance genes and initiate its attack on the human host. Interception of the competence regulon can therefore be utilized to study S. pneumoniae cell-cell communication and behavioral changes, as well as attenuate S. pneumoniae infectivity. Herein we report the design and synthesis of cyclic dominant negative competence-stimulating peptide (dnCSP) analogs capable of intercepting the competence regulon in both S. pneumoniae specificity groups with activities at the low nanomolar range. Structural analysis of lead analogs provided important insights as to the molecular mechanism that drives CSP receptor binding and revealed that the pan-group cyclic CSPs exhibit a chimeric hydrophobic patch conformation that resembles the hydrophobic patches required for both ComD1 and ComD2 binding. Moreover, the lead cyclic dnCSP, CSP1-E1A-cyc(Dap6E10), was found to possess superior pharmacological properties, including improved resistance to enzymatic degradation, while remaining nontoxic. Lastly, CSP1-E1A-cyc(Dap6E10) was capable of attenuating mouse mortality during acute pneumonia caused by both group 1 and group 2 S. pneumoniae strains. This cyclic pan-group dnCSP is therefore a promising drug lead scaffold against S. pneumoniae infections that could be administered individually or utilized in combination therapy to augment the effects of current antimicrobial agents.
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Affiliation(s)
- Yifang Yang
- Department of Chemistry, University of Nevada, Reno, Reno, NV 89557
| | - Jingjun Lin
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL 61802
| | | | - Gabriel Cornilescu
- National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, WI 53706
| | - Gee W Lau
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL 61802;
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, Reno, NV 89557;
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Ghorbanzadeh R, Assadian H, Chiniforush N, Parker S, Pourakbari B, Ehsani B, Alikhani MY, Bahador A. Modulation of virulence in Enterococcus faecalis cells surviving antimicrobial photodynamic inactivation with reduced graphene oxide-curcumin: An ex vivo biofilm model. Photodiagnosis Photodyn Ther 2019; 29:101643. [PMID: 31899382 DOI: 10.1016/j.pdpdt.2019.101643] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/14/2019] [Accepted: 12/27/2019] [Indexed: 11/18/2022]
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. 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. 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 s). 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. 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.
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Affiliation(s)
| | - Hadi Assadian
- Department of Endodontics, Shahed University, Tehran, Iran
| | - Nasim Chiniforush
- Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Italy
| | - Steven Parker
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Italy
| | - Babak Pourakbari
- Pediatric Infectious Disease Research Center, Tehran University of Medical Science, Tehran, Iran
| | - Babak Ehsani
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Yousef Alikhani
- Department of Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
| | - Abbas Bahador
- Oral Microbiology Laboratory, Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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Risks associated with enterococci as probiotics. Food Res Int 2019; 129:108788. [PMID: 32036912 DOI: 10.1016/j.foodres.2019.108788] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/07/2019] [Accepted: 10/29/2019] [Indexed: 01/01/2023]
Abstract
Probiotics are naturally occurring microorganisms that confer health benefits by altering host commensal microbiota, modulating immunity, enhancing intestinal barrier function, or altering pain perception. Enterococci are human and animal intestinal commensals that are used as probiotics and in food production. These microorganisms, however, express many virulence traits including cytolysin, proteases, aggregation substance, capsular polysaccharide, enterococcal surface protein, biofilm formation, extracellular superoxide, intestinal translocation, and resistance to innate immunity that can lead to serious hospital-acquired infections. In addition, enterococci are facile in acquiring antibiotic resistance genes to many clinically important antibiotics encoded on a wide variety of conjugative plasmids, transposons, and bacteriophages. The pathogenicity and disease burden caused by enterococci render them poor choices as probiotics. No large, randomized, placebo-controlled clinical trials have demonstrated the safety and efficacy of any enterococcal probiotic. As a result, no enterococcal probiotic has been approved by the United States Food and Drug Administration for the treatment, cure, or amelioration of human disease. In 2007, the European Food Safety Authority concluded that enterococci do not meet the standard for "Qualified Presumption of Safety". Enterococcal strains used or proposed for use as probiotics should be carefully screened for efficacy and safety.
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Enterococcus faecalis Enhances Expression and Activity of the Enterohemorrhagic Escherichia coli Type III Secretion System. mBio 2019; 10:mBio.02547-19. [PMID: 31744919 PMCID: PMC6867897 DOI: 10.1128/mbio.02547-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The gut microbiota can significantly impact invading pathogens and the disease they cause; however, many of the mechanisms that dictate commensal-pathogen interactions remain unclear. Enterohemorrhagic Escherichia coli (EHEC) is a potentially lethal human intestinal pathogen that uses microbiota-derived molecules as cues to efficiently regulate virulence factor expression. Here, we investigate the interaction between EHEC and Enterococcus faecalis, a common human gut commensal, and show that E. faecalis affects both expression and activity of the EHEC type III secretion system (T3SS) via two distinct mechanisms. First, in the presence of E. faecalis there is increased transcription of genes encoding the EHEC T3SS. This leads to increased effector translocation and ultimately greater numbers of pedestals formed on host cells. The same effect was observed with several strains of enterococci, suggesting that it is a general characteristic of this group. In a mechanism separate from E. faecalis-induced transcription of the T3SS, we report that an E. faecalis-secreted protease, GelE, cleaves a critical structural component of the EHEC T3SS, EspB. Our data suggest that this cleavage actually increases effector translocation by the T3SS, supporting a model where EspB proteolysis promotes maximum T3SS activity. Finally, we report that treatment of EHEC with E. faecalis-conditioned cell-free medium is insufficient to induce increased T3SS expression, suggesting that this effect relies on cell contact between E. faecalis and EHEC. This work demonstrates a complex interaction between a human commensal and pathogen that impacts both expression and function of a critical virulence factor.IMPORTANCE This work reveals a complex and multifaceted interaction between a human gut commensal, Enterococcus faecalis, and a pathogen, enterohemorrhagic E. coli We demonstrate that E. faecalis enhances expression of the enterohemorrhagic E. coli type III secretion system and that this effect likely depends on cell contact between the commensal and the pathogen. Additionally, the GelE protease secreted by E. faecalis cleaves a critical structural component of the EHEC type III secretion system. In agreement with previous studies, we find that this cleavage actually increases effector protein delivery into host cells by the secretion system. This work demonstrates that commensal bacteria can significantly shape expression and activity of pathogen virulence factors, which may ultimately shape the progression of disease.
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Littlewood S, Tattersall H, Hughes CS, Hussain R, Ma P, Harding SE, Nakayama J, Phillips-Jones MK. The gelatinase biosynthesis-activating pheromone binds and stabilises the FsrB membrane protein in Enterococcus faecalis quorum sensing. FEBS Lett 2019; 594:553-563. [PMID: 31598959 PMCID: PMC7028047 DOI: 10.1002/1873-3468.13634] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/27/2019] [Accepted: 09/30/2019] [Indexed: 12/14/2022]
Abstract
Quorum‐sensing mechanisms regulate gene expression in response to changing cell‐population density detected through pheromones. In Enterococcus faecalis, Fsr quorum sensing produces and responds to the gelatinase biosynthesis‐activating pheromone (GBAP). Here we establish that the enterococcal FsrB membrane protein has a direct role connected with GBAP by showing that GBAP binds to purified FsrB. Far‐UV CD measurements demonstrated a predominantly α‐helical protein exhibiting a small level of conformational flexibility. Fivefold (400 μm) GBAP stabilised FsrB (80 μm) secondary structure. FsrB thermal denaturation in the presence and absence of GBAP revealed melting temperatures of 70.1 and 60.8 °C, respectively, demonstrating GBAP interactions and increased thermal stability conferred by GBAP. Addition of GBAP also resulted in tertiary structural changes, confirming GBAP binding.
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Affiliation(s)
- Sean Littlewood
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, UK
| | - Helena Tattersall
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, UK
| | - Charlotte S Hughes
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, UK.,Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, UK
| | - Rohanah Hussain
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, UK
| | - Pikyee Ma
- Astbury Centre for Structural Molecular Biology, University of Leeds, UK
| | - Stephen E Harding
- National Centre for Macromolecular Hydrodynamics, School of Biosciences, University of Nottingham, Sutton Bonington, UK
| | - Jiro Nakayama
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka, Japan
| | - Mary K Phillips-Jones
- National Centre for Macromolecular Hydrodynamics, School of Biosciences, University of Nottingham, Sutton Bonington, UK
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Fiore E, Van Tyne D, Gilmore MS. Pathogenicity of Enterococci. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0053-2018. [PMID: 31298205 PMCID: PMC6629438 DOI: 10.1128/microbiolspec.gpp3-0053-2018] [Citation(s) in RCA: 208] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Indexed: 12/19/2022] Open
Abstract
Enterococci are unusually well adapted for survival and persistence in a variety of adverse environments, including on inanimate surfaces in the hospital environment and at sites of infection. This intrinsic ruggedness undoubtedly played a role in providing opportunities for enterococci to interact with other overtly drug-resistant microbes and acquire additional resistances on mobile elements. The rapid rise of antimicrobial resistance among hospital-adapted enterococci has rendered hospital-acquired infections a leading therapeutic challenge. With about a quarter of a genome of additional DNA conveyed by mobile elements, there are undoubtedly many more properties that have been acquired that help enterococci persist and spread in the hospital setting and cause diseases that have yet to be defined. Much remains to be learned about these ancient and rugged microbes, particularly in the area of pathogenic mechanisms involved with human diseases.
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Affiliation(s)
- Elizabeth Fiore
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA 02114
- Department of Microbiology, Harvard Medical School, Boston, MA 02115
| | - Daria Van Tyne
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA 02114
- Department of Microbiology, Harvard Medical School, Boston, MA 02115
| | - Michael S Gilmore
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA 02114
- Department of Microbiology, Harvard Medical School, Boston, MA 02115
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McBrayer DN, Gantman BK, Tal-Gan Y. N-Methylation of Amino Acids in Gelatinase Biosynthesis-Activating Pheromone Identifies Key Site for Stability Enhancement with Retention of the Enterococcus faecalis fsr Quorum Sensing Circuit Response. ACS Infect Dis 2019; 5:1035-1041. [PMID: 30973007 DOI: 10.1021/acsinfecdis.9b00097] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The growing prevalence of multiantibiotic-resistant bacteria necessitates looking at potential alternative approaches for attenuating infections by bacteria while reducing the rate of antibiotic resistance development. Enterococcus faecalis is responsible for a large percentage of clinical enterococci infections, and its pathogenicity has been demonstrated to be influenced by quorum sensing (QS). In this study, we report the systematic study of the relationship between backbone hydrogens and the ability to activate the FsrC receptor. We demonstrate that N-methylation was particularly well-tolerated at one site (Phe7) and granted stability against protease digestion, increasing the peptide half-life relative to the native signal by more than 6-fold. The inclusion of the N-Me-Phe7 modification may be useful for improving the pharmacological properties of E. faecalis QS inhibitors as part of the development of future therapeutic candidates.
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Affiliation(s)
- Dominic N. McBrayer
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, United States
| | - Brooke K. Gantman
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, United States
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, United States
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Kumar D, Sun Z, Cao G, Xue R, Hu X, Gong C. Bombyx mori bidensovirus infection alters the intestinal microflora of fifth instar silkworm (Bombyx mori) larvae. J Invertebr Pathol 2019; 163:48-63. [DOI: 10.1016/j.jip.2019.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 03/08/2019] [Accepted: 03/09/2019] [Indexed: 01/06/2023]
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Abstract
The study of the genetics of enterococci has focused heavily on mobile genetic elements present in these organisms, the complex regulatory circuits used to control their mobility, and the antibiotic resistance genes they frequently carry. Recently, more focus has been placed on the regulation of genes involved in the virulence of the opportunistic pathogenic species Enterococcus faecalis and Enterococcus faecium. Little information is available concerning fundamental aspects of DNA replication, partition, and division; this article begins with a brief overview of what little is known about these issues, primarily by comparison with better-studied model organisms. A variety of transcriptional and posttranscriptional mechanisms of regulation of gene expression are then discussed, including a section on the genetics and regulation of vancomycin resistance in enterococci. The article then provides extensive coverage of the pheromone-responsive conjugation plasmids, including sections on regulation of the pheromone response, the conjugative apparatus, and replication and stable inheritance. The article then focuses on conjugative transposons, now referred to as integrated, conjugative elements, or ICEs, and concludes with several smaller sections covering emerging areas of interest concerning the enterococcal mobilome, including nonpheromone plasmids of particular interest, toxin-antitoxin systems, pathogenicity islands, bacteriophages, and genome defense.
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Aladarose BE, Said HS, Abdelmegeed ES. Incidence of Virulence Determinants Among Enterococcal Clinical Isolates in Egypt and Its Association with Biofilm Formation. Microb Drug Resist 2019; 25:880-889. [PMID: 30811265 DOI: 10.1089/mdr.2018.0320] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Background: Although Enterococci compromise an essential part of normal gut microbiota of both animals and humans, they have emerged as a leading opportunistic pathogen causing infections. The pathogenesis of enterococci is attributed to an array of virulence determinants. Objectives: This study aims to explore the prevalence and characteristics of enterococcal clinical isolates collected from Mansoura University Hospitals, Egypt, assess their ability to form biofilm, and the correlation with virulence determinants and antimicrobial resistance. Materials and Methods: A total of 70 Enterococcal clinical isolates were collected from different clinical sources between June and December 2016. Biofilm formation capacity was assessed, and characterization of virulence factors and antibiotic susceptibility was performed. Clonal relatedness between isolates was assessed using enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) approach. Results and Conclusion: The molecular analysis demonstrated high genetic diversity among enterococcal clinical isolates. The gelE was the most frequently detected gene (91.4%), followed by asa1 (70%), esp (65.7%), and cylA (17.1%), while hyl was not detected in any isolate. Gelatinase activity was detected in 35.7%, while hemolysin and lipase activity was detected in 12.9% and 78.5%, respectively. Most of the enterococcal isolates were biofilm producers, of which 67.1% were strong/moderate biofilm producers. All linezolid-resistant isolates exhibited strong/moderate biofilm formation capacity. Strong/moderate biofilm formation was more frequently observed among esp-positive (esp+) and gelatinase nonproducing (gelatinase-) enterococcal isolates. Multiple regression analysis denoted that esp (odds ratio [OR] 5.371, p = 0.003) and gelatinase production (OR 0.264, p = 0.015) were associated with strong/moderate biofilm formation capacity. These findings suggest that esp gene positivity and gelatinase production may affect biofilm formation capacity among enterococcal clinical isolates.
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Affiliation(s)
| | - Heba Shehta Said
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
| | - Eman Salama Abdelmegeed
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
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Bolhari B, Bahador A, Khoshkhounejad M, Afshar MS, Moghaddaszadeh M. Evaluation of the Effect of MTAD on Expression of Enterococcus faecalis Virulence Factors Considering the Role of Different Obturating Materials. JOURNAL OF DENTISTRY (TEHRAN, IRAN) 2018; 15:382-392. [PMID: 30842799 PMCID: PMC6399463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVES The aim of this study was to determine the effect of MTAD on the expression of virulence factors of Enterococcus faecalis (E.faecalis) considering the role of Guttapercha/AH26 or Resilon/RealSeal SE as root canal obturating materials. MATERIALS AND METHODS One-hundred and forty-four single-rooted human teeth were instrumented to a standardized apical size. Root canals were infected by E.faecalis (ATCC 29212). Ninety teeth were irrigated with MTAD and randomly divided into three groups. In two groups, root canals were obturated by either Gutta-percha/AH26 or Resilon/RealSeal SE. Root canals were kept unobturated in the third group. The remaining 54 teeth received no final irrigation. All groups were then subdivided into three timepoint subgroups in which dentin powder was obtained from each sample to determine the expression of specific virulence factors of E.faecalis (efa, esp, gel, fsr) using real-time reverse transcription polymerase chain reaction (RT-PCR). Statistical analysis was performed by one-way analysis of variance (ANOVA) and Tukey's post-hoc test. The statistical power was set at P-value ≤0.05. RESULTS MTAD was effective against the expression of most of the tested virulence factors, and Gutta-percha/AH26 increased the antibacterial efficacy of MTAD. CONCLUSIONS MTAD could inhibit the expression of some known virulence factors of E.faecalis at the majority of tested timepoints. This may partly explain some of the mechanisms of antimicrobial efficacy of MTAD against this resistant microorganism which is known as one of the main causes of failure of root canal treatment.
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Affiliation(s)
- Behnam Bolhari
- Associate Professor, Department of Endodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran; Laser Research Center in Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Abbas Bahador
- Associate Professor, Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehrfam Khoshkhounejad
- Assistant Professor, Department of Endodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran,Corresponding author: M. Khoshkhounejad, Department of Endodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahsa Sobhi Afshar
- Assistant Professor, Department of Endodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
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Colomer-Winter C, Gaca AO, Chuang-Smith ON, Lemos JA, Frank KL. Basal levels of (p)ppGpp differentially affect the pathogenesis of infective endocarditis in Enterococcus faecalis. MICROBIOLOGY (READING, ENGLAND) 2018; 164:1254-1265. [PMID: 30091695 PMCID: PMC6600344 DOI: 10.1099/mic.0.000703] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Accepted: 07/18/2018] [Indexed: 12/19/2022]
Abstract
The alarmone (p)ppGpp mediates the stringent response and has a recognized role in bacterial virulence. We previously reported a stringent response-like state in Enterococcus faecalis isolated from a rabbit foreign body abscess model and showed that E. faecalis mutants with varying levels of cellular (p)ppGpp [Δrel, ΔrelQ and the (p)ppGpp0 ΔrelΔrelQ] had differential abilities to persist within abscesses. In this study, we investigated whether (p)ppGpp contributes to the pathogenesis of E. faecalis infective endocarditis (IE), a biofilm infection of the heart valves. While the stringent response was not activated in heart valve-associated E. faecalis, deletion of the gene encoding the bifunctional (p)ppGpp synthetase/hydrolase Rel significantly impaired valve colonization. These results indicate that the presence of (p)ppGpp is dispensable for E. faecalis to cause IE, whereas the ability to regulate (p)ppGpp levels is critical for valve colonization. Next, we characterized how basal (p)ppGpp levels affect processes associated with IE pathogenesis. Despite being defective in binding to BSA-coated polystyrene surfaces, the Δrel strain bound to collagen- and fibronectin-coated surfaces and ex vivo porcine heart valves as well as the parent and ΔrelΔrelQ strains, ruling out the possibility that the impaired IE phenotype was due to an attachment defect. Moreover, differences in cellular (p)ppGpp levels did not affect extracellular gelatinase activity but significantly impaired enterococcal invasion of human coronary artery endothelial cells. Taken together, this study uncovers for the first time the fact that differences in basal (p)ppGpp levels, rather than the stringent response, differentially affect processes that contribute to the pathogenesis of IE.
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Affiliation(s)
- Cristina Colomer-Winter
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Anthony O. Gaca
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
- Present address: Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Olivia N. Chuang-Smith
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA
- Present address: Bridge to MD and Pathway to American University of Antigua (AUA) Programs, Manipal Education Americas, LLC, New York, NY, USA
| | - José A. Lemos
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Kristi L. Frank
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, USA
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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McBrayer DN, Cameron CD, Gantman BK, Tal-Gan Y. Rational Design of Potent Activators and Inhibitors of the Enterococcus faecalis Fsr Quorum Sensing Circuit. ACS Chem Biol 2018; 13:2673-2681. [PMID: 30141904 DOI: 10.1021/acschembio.8b00610] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The increasing rate of resistance development to conventional antibiotics by bacteria necessitates the identification of alternative treatment possibilities that can reduce the ability of bacteria to adapt. Enterococcus faecalis remains the leading cause of clinical enterococci infections and has exhibited quorum sensing (QS)-dependent pathogenicity. Here, we report the development of macrocyclic peptide-based activators and inhibitors of the E. faecalis Fsr QS circuitry. To this end, we developed, optimized, and compared three synthetic routes for lactone-containing macrocyclic peptide scaffolds. We then utilized previous and current structure-activity relationship (SAR) insights of the native QS signaling peptide to rationally design the most potent activators and inhibitors of the Fsr QS circuitry identified to date. The application of these peptides could provide a means to attenuate the pathogenicity of E. faecalis without introducing significant selective pressure on the bacteria to develop resistance.
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Affiliation(s)
- Dominic N. McBrayer
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, United States
| | - Crissey D. Cameron
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, United States
| | - Brooke K. Gantman
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, United States
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, United States
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Long-Term Colonization Dynamics of Enterococcus faecalis in Implanted Devices in Research Macaques. Appl Environ Microbiol 2018; 84:AEM.01336-18. [PMID: 30006402 DOI: 10.1128/aem.01336-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 07/10/2018] [Indexed: 12/22/2022] Open
Abstract
Enterococcus faecalis is a common opportunistic pathogen that colonizes cephalic recording chambers (CRCs) of macaques used in cognitive neuroscience research. We previously characterized 15 E. faecalis strains isolated from macaques at the Massachusetts Institute of Technology (MIT) in 2011. The goal of this study was to examine how a 2014 protocol change prohibiting the use of antimicrobials within CRCs affected colonizing E. faecalis strains. We collected 20 E. faecalis isolates from 10 macaques between 2013 and 2017 for comparison to 4 isolates previously characterized in 2011 with respect to the sequence type (ST) distribution, antimicrobial resistance, biofilm formation, and changes in genes that might confer a survival advantage. ST4 and ST55 were predominant among the isolates characterized in 2011, whereas the less antimicrobial-resistant lineage ST48 emerged to dominance after 2013. Two macaques remained colonized by ST4 and ST55 strains for 5 and 4 years, respectively. While the antimicrobial resistance and virulence factors identified in these ST4 and ST55 strains remained relatively stable, we detected an increase in biofilm formation ability over time in both isolates. We also found that ST48 strains were typically robust biofilm formers, which could explain why this ST increased in prevalence. Finally, we identified mutations in the DNA mismatch repair genes mutS and mutL in separate ST55 and ST4 strains and confirmed that strains bearing these mutations displayed a hypermutator phenotype. The presence of a hypermutator phenotype may complicate future antimicrobial treatment for clinically relevant E. faecalis infections in macaques.IMPORTANCEEnterococcus faecalis is a common cause of health care-associated infections in humans, largely due to its ability to persist in the hospital environment, colonize patients, acquire antimicrobial resistance, and form biofilms. Understanding how enterococci evolve in health care settings provides insight into factors affecting enterococcal survival and persistence. Macaques used in neuroscience research have long-term cranial implants that, despite best practices, often become colonized by E. faecalis This provides a unique opportunity to noninvasively examine the evolution of enterococci on a long-term indwelling device. We collected E. faecalis strains from cephalic implants over a 7-year period and characterized the sequence type, antimicrobial resistance, virulence factors, biofilm production, and hypermutator phenotypes. Improved antimicrobial stewardship allowed a less-antimicrobial-resistant E. faecalis strain to predominate at the implant interface, potentially improving antimicrobial treatment outcomes if future clinical infections occur. Biofilm formation appears to play an important role in the persistence of the E. faecalis strains associated with these implants.
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Xu W, Flores-Mireles AL, Cusumano ZT, Takagi E, Hultgren SJ, Caparon MG. Host and bacterial proteases influence biofilm formation and virulence in a murine model of enterococcal catheter-associated urinary tract infection. NPJ Biofilms Microbiomes 2017; 3:28. [PMID: 29134108 PMCID: PMC5673934 DOI: 10.1038/s41522-017-0036-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/27/2017] [Accepted: 10/03/2017] [Indexed: 12/19/2022] Open
Abstract
Enterococcus faecalis is a leading causative agent of catheter-associated urinary tract infection (CAUTI), the most common hospital-acquired infection. Its ability to grow and form catheter biofilm is dependent upon host fibrinogen (Fg). Examined here are how bacterial and host proteases interact with Fg and contribute to virulence. Analysis of mutants affecting the two major secreted proteases of E. faecalis OG1RF (GelE, SprE) revealed that while the loss of either had no effect on virulence in a murine CAUTI model or for formation of Fg-dependent biofilm in urine, the loss of both resulted in CAUTI attenuation and defective biofilm formation. GelE−, but not SprE− mutants, lost the ability to degrade Fg in medium, while paradoxically, both could degrade Fg in urine. The finding that SprE was activated independently of GelE in urine by a host trypsin-like protease resolved this paradox. Treatment of catheter-implanted mice with inhibitors of both host-derived and bacterial-derived proteases dramatically reduced catheter-induced inflammation, significantly inhibited dissemination from bladder to kidney and revealed an essential role for a host cysteine protease in promoting pathogenesis. These data show that both bacterial and host proteases contribute to CAUTI, that host proteases promote dissemination and suggest new strategies for therapeutic intervention. Identifying bacterial and host enzymes that support biofilm formation may help prevent urinary tract infections caused by catheters. Enterococcus faecalis bacteria is a leading cause of catheter-associated urinary tract infections, the most common type of hospital-acquired infections. Michael Caparon and colleagues at Washington University School of Medicine in Missouri, USA, studied these infections in mice. They examined the effects of two protein-degrading enzymes, both from the bacterium and one can be activated by urine trypsin-like protease from the animals. Mutations that impaired either one of the enzymes had no effect on the infection, but when both the bacterial enzymes were impaired by mutation the formation of biofilms was significantly reduced. Treating the mice with chemicals that inhibited both bacterial and host enzymes dramatically reduced catheter-induced inflammation and related problems. This suggests drugs targeting these enzymes could be useful in clinical care.
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Affiliation(s)
- Wei Xu
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO 63110-1093 USA
| | - Ana L Flores-Mireles
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO 63110-1093 USA
| | - Zachary T Cusumano
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO 63110-1093 USA.,Present Address: NextCure Inc., Beltsville, MD USA
| | - Enzo Takagi
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO 63110-1093 USA
| | - Scott J Hultgren
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO 63110-1093 USA
| | - Michael G Caparon
- Department of Molecular Microbiology, Center for Women's Infectious Disease Research, Washington University School of Medicine, Saint Louis, MO 63110-1093 USA
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Stinemetz EK, Gao P, Pinkston KL, Montealegre MC, Murray BE, Harvey BR. Processing of the major autolysin of E. faecalis, AtlA, by the zinc-metalloprotease, GelE, impacts AtlA septal localization and cell separation. PLoS One 2017; 12:e0186706. [PMID: 29049345 PMCID: PMC5648223 DOI: 10.1371/journal.pone.0186706] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/05/2017] [Indexed: 01/23/2023] Open
Abstract
AtlA is the major peptidoglycan hydrolase of Enterococcus faecalis involved in cell division and cellular autolysis. The secreted zinc metalloprotease, gelatinase (GelE), has been identified as an important regulator of cellular function through post-translational modification of protein substrates. AtlA is a known target of GelE, and their interplay has been proposed to regulate AtlA function. To study the protease-mediated post-translational modification of AtlA, monoclonal antibodies were developed as research tools. Flow cytometry and Western blot analysis suggests that in the presence of GelE, surface-bound AtlA exists primarily as a N-terminally truncated form whereas in the absence of GelE, the N-terminal domain of AtlA is retained. We identified the primary GelE cleavage site occurring near the transition between the T/E rich Domain I and catalytic region, Domain II via N-terminal sequencing. Truncation of AtlA had no effect on the peptidoglycan hydrolysis activity of AtlA. However, we observed that N-terminal cleavage was required for efficient AtlA-mediated cell division while unprocessed AtlA was unable to resolve dividing cells into individual units. Furthermore, we observed that the processed AtlA has the propensity to localize to the cell septum on wild-type cells whereas unprocessed AtlA in the ΔgelE strain were dispersed over the cell surface. Combined, these results suggest that AtlA septum localization and subsequent cell separation can be modulated by a single GelE-mediated N-terminal cleavage event, providing new insights into the post-translation modification of AtlA and the mechanisms governing chaining and cell separation.
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Affiliation(s)
- Emily K. Stinemetz
- Center for Molecular Imaging, Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center, Houston, Texas, United States of America
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, United States of America
| | - Peng Gao
- Center for Molecular Imaging, Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center, Houston, Texas, United States of America
| | - Kenneth L. Pinkston
- Center for Molecular Imaging, Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center, Houston, Texas, United States of America
| | - Maria Camila Montealegre
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, United States of America
| | - Barbara E. Murray
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, United States of America
- Division of Infectious Disease, Department of Internal Medicine, University of Texas Health Science Center, Houston, Texas, United States of America
| | - Barrett R. Harvey
- Center for Molecular Imaging, Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center, Houston, Texas, United States of America
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, United States of America
- Division of Infectious Disease, Department of Internal Medicine, University of Texas Health Science Center, Houston, Texas, United States of America
- * E-mail:
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Hwanhlem N, Ivanova T, Biscola V, Choiset Y, Haertlé T. Bacteriocin producing Enterococcus faecalis isolated from chicken gastrointestinal tract originating from Phitsanulok, Thailand: Isolation, screening, safety evaluation and probiotic properties. Food Control 2017. [DOI: 10.1016/j.foodcont.2017.02.060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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