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Archambaud C, Nunez N, da Silva RAG, Kline KA, Serror P. Enterococcus faecalis: an overlooked cell invader. Microbiol Mol Biol Rev 2024; 88:e0006924. [PMID: 39239986 PMCID: PMC11426025 DOI: 10.1128/mmbr.00069-24] [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] [Indexed: 09/07/2024] Open
Abstract
SUMMARYEnterococcus faecalis and Enterococcus faecium are human pathobionts that exhibit a dual lifestyle as commensal and pathogenic bacteria. The pathogenic lifestyle is associated with specific conditions involving host susceptibility and intestinal overgrowth or the use of a medical device. Although the virulence of E. faecium appears to benefit from its antimicrobial resistance, E. faecalis is recognized for its higher pathogenic potential. E. faecalis has long been considered a predominantly extracellular pathogen; it adheres to and is taken up by a wide range of mammalian cells, albeit with less efficiency than classical intracellular enteropathogens. Carbohydrate structures, rather than proteinaceous moieties, are likely to be primarily involved in the adhesion of E. faecalis to epithelial cells. Consistently, few adhesins have been implicated in the adhesion of E. faecalis to epithelial cells. On the host side, very little is known about cognate receptors, except for the role of glycosaminoglycans during macrophage infection. Several lines of evidence indicate that E. faecalis internalization may involve a zipper-like mechanism as well as a macropinocytosis pathway. Conversely, E. faecalis can use several strategies to prevent engulfment in phagocytes. However, the bacterial and host mechanisms underlying cell infection by E. faecalis are still in their infancy. The most recent striking finding is the existence of an intracellular lifestyle where E. faecalis can replicate within a variety of host cells. In this review, we summarize and discuss the current knowledge of E. faecalis-host cell interactions and argue on the need for further mechanistic studies to prevent or reduce infections.
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Affiliation(s)
- Cristel Archambaud
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Natalia Nunez
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Ronni A G da Silva
- Singapore-MIT Alliance for Research and Technology, Antimicrobial Drug Resistance Interdisciplinary Research Group, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Pascale Serror
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
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Ruhal R, Sahu A, Koujalagi T, Das A, Prasanth H, Kataria R. Biofilm-specific determinants of enterococci pathogen. Arch Microbiol 2024; 206:397. [PMID: 39249569 DOI: 10.1007/s00203-024-04119-9] [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: 06/19/2024] [Revised: 08/20/2024] [Accepted: 08/25/2024] [Indexed: 09/10/2024]
Abstract
Amongst all Enterococcus spp., E. faecalis and E. faecium are most known notorious pathogen and their biofilm formation has been associated with endocarditis, oral, urinary tract, and wound infections. Biofilm formation involves a pattern of initial adhesion, microcolony formation, and mature biofilms. The initial adhesion and microcolony formation involve numerous surface adhesins e.g. pili Ebp and polysaccharide Epa. The mature biofilms are maintained by eDNA, It's worth noting that phage-mediated dispersal plays a prominent role. Further, the involvement of peptide pheromones in regulating biofilm maintenance sets it apart from other pathogens and facilitating the horizontal transfer of resistance genes. The role of fsr based regulation by regulating gelE expression is also discussed. Thus, we provide a concise overview of the significant determinants at each stage of Enterococcus spp. biofilm formation. These elements could serve as promising targets for antibiofilm strategies.
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Affiliation(s)
- Rohit Ruhal
- School of Bio Science and Technology, VIT Vellore, Vellore, Tamil Nadu, 632014, India.
| | - Abhijeet Sahu
- School of Bio Science and Technology, VIT Vellore, Vellore, Tamil Nadu, 632014, India
| | - Tushar Koujalagi
- School of Bio Science and Technology, VIT Vellore, Vellore, Tamil Nadu, 632014, India
| | - Ankumoni Das
- School of Bio Science and Technology, VIT Vellore, Vellore, Tamil Nadu, 632014, India
| | - Hema Prasanth
- School of Bio Science and Technology, VIT Vellore, Vellore, Tamil Nadu, 632014, India
| | - Rashmi Kataria
- School of Bio Science and Technology, VIT Vellore, Vellore, Tamil Nadu, 632014, India
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3
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Joyce LR, Kim S, Spencer BL, Christensen PM, Palmer KL, Guan Z, Siegenthaler JA, Doran KS. Streptococcus agalactiae glycolipids promote virulence by thwarting immune cell clearance. SCIENCE ADVANCES 2024; 10:eadn7848. [PMID: 38809989 PMCID: PMC11135403 DOI: 10.1126/sciadv.adn7848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 04/25/2024] [Indexed: 05/31/2024]
Abstract
Streptococcus agalactiae [group B Streptococcus (GBS)] is a leading cause of neonatal meningitis, with late-onset disease (LOD) occurring after gastrointestinal tract colonization in infants. Bacterial membrane lipids are essential for host-pathogen interactions, and the functions of glycolipids are yet to be fully elucidated. GBS synthesizes three major glycolipids: glucosyl-diacylglycerol (Glc-DAG), diglucosyl-DAG (Glc2-DAG), and lysyl-Glc-DAG (Lys-Glc-DAG). Here, we identify the enzyme, IagB, as responsible for biosynthesis of Glc-DAG, the precursor for the two other glycolipids in GBS. To examine the collective role of glycolipids to GBS virulence, we adapted a murine model of neonatal meningitis to simulate LOD. The GBS∆iagB mutant traversed the gut-epithelial barrier comparable to wild type but was severely attenuated in bloodstream survival, resulting in decreased bacterial loads in the brain. The GBS∆iagB mutant was more susceptible to neutrophil killing and membrane targeting by host antimicrobial peptides. This work reveals an unexplored function of GBS glycolipids with their ability to protect the bacterial cell from host antimicrobial killing.
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Affiliation(s)
- Luke R. Joyce
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Sol Kim
- Department of Pediatrics, Section of Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Brady L. Spencer
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Priya M. Christensen
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, USA
| | - Kelli L. Palmer
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, USA
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Julie A. Siegenthaler
- Department of Pediatrics, Section of Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Kelly S. Doran
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
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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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Wang X, Li M, Yang Y, Shang X, Wang Y, Li Y. Clinical significance of inflammatory markers for evaluating disease severity of mixed-pathogen bloodstream infections of both Enterococcus spp. and Candida spp. Heliyon 2024; 10:e26873. [PMID: 38434384 PMCID: PMC10907801 DOI: 10.1016/j.heliyon.2024.e26873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 02/17/2024] [Accepted: 02/21/2024] [Indexed: 03/05/2024] Open
Abstract
Objective In recent decades, there has been a notable increase in the morbidity and mortality rates linked to bacteremia and candidemia. This study aimed to investigate the clinical significance of inflammatory markers in assessing the disease severity in critically ill patients suffering from mixed-bloodstream infections (BSIs) due to Enterococcus spp. and Candida spp. Methods In this retrospective research, patients diagnosed with BSIs who were admitted to the intensive care unit (ICU) during the period of January 2019 to December 2022 were analyzed. The patients were divided into two groups: a mixed-pathogen BSI group with both Enterococcus spp. and Candida spp., and a single-pathogen BSI group with only Enterococcus spp. The study examined the differences in inflammatory marker levels and disease severity, including Acute Physiology and Chronic Health Evaluation (APACHE) II scores, duration of ICU stay, and 30-day mortality, between the two groups. Furthermore, we sought to scrutinize the potential associations among these aforementioned parameters. Results The neutrophil-to-lymphocyte ratios (NLRs) and levels of plasma C-reactive protein (CRP), interleukin (IL)-6, IL-8, and tumor necrosis factor-α (TNF-α) in the mixed-pathogen BSI group were higher than those in the single-pathogen BSI group. Spearman's rank correlation analysis showed that NLRs and plasma CRP and IL-6 levels were positively correlated with disease severity in the mixed-pathogen BSI group. Further, the levels of plasma IL-8 and TNF-α were also positively correlated with ICU stay duration and 30-day mortality. In multivariate analysis, plasma CRP and IL-6 levels were independently associated with 30-day mortality. Conclusion Mixed-pathogen BSIs caused by Enterococcus spp. and Candida spp. may give rise to increased NLRs and plasma CRP, IL-6, IL-8, and TNF-α levels in comparison to BSI caused by Enterococcus spp. only, thus leading to elevated disease severity in critically ill patients.
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Affiliation(s)
- Xin Wang
- Department of Critical Care Medicine, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, 100071, China
| | - Ming Li
- Department of Clinical Laboratory, The First Medical Center of Chinese PLA General Hospital, Beijing, 100039, China
| | - Yang Yang
- Department of Critical Care Medicine, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, 100071, China
| | - Xueyi Shang
- Department of Critical Care Medicine, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, 100071, China
| | - Yonggang Wang
- Department of Critical Care Medicine, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, 100071, China
| | - Yan Li
- Department of Critical Care Medicine, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, 100071, China
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Yoo JS, Goh B, Heo K, Jung DJ, Zheng W, Lee CC, Geva-Zatorsky N, Wu M, Park SB, Kasper DL, Oh SF. Functional and metagenomic level diversities of human gut symbiont-derived glycolipids. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.23.541633. [PMID: 37293019 PMCID: PMC10245877 DOI: 10.1101/2023.05.23.541633] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Bioactive metabolites produced by symbiotic microbiota causally impact host health and disease, nonetheless, incomplete functional annotation of genes as well as complexities and dynamic nature of microbiota make understanding species-level contribution in production and actions difficult. Alpha-galactosylceramides produced by Bacteroides fragilis (BfaGC) are one of the first modulators of colonic immune development, but biosynthetic pathways and the significance of the single species in the symbiont community still remained elusive. To address these questions at the microbiota level, we have investigated the lipidomic profiles of prominent gut symbionts and the metagenome-level landscape of responsible gene signatures in the human gut. We first elucidated the chemical diversity of sphingolipid biosynthesis pathways of major bacterial species. In addition to commonly shared ceramide backbone synthases showing two distinct intermediates, alpha-galactosyltransferase (agcT), the necessary and sufficient component for BfaGC production and host colonic type I natural killer T (NKT) cell regulation by B. fragilis, was characterized by forward-genetics based targeted metabolomic screenings. Phylogenetic analysis of agcT in human gut symbionts revealed that only a few ceramide producers have agcT and hence can produce aGCs, on the other hand, structurally conserved homologues of agcT are widely distributed among species lacking ceramides. Among them, alpha-glucosyl-diacylglycerol(aGlcDAG)-producing glycosyltransferases with conserved GT4-GT1 domains are one of the most prominent homologs in gut microbiota, represented by Enterococcus bgsB . Of interest, aGlcDAGs produced by bgsB can antagonize BfaGC-mediated activation of NKT cells, showing the opposite, lipid structure-specific actions to regulate host immune responses. Further metagenomic analysis of multiple human cohorts uncovered that the agcT gene signature is almost exclusively contributed by B. fragilis , regardless of age, geographical and health status, where the bgsB signature is contributed by >100 species, of which abundance of individual microbes is highly variable. Our results collectively showcase the diversities of gut microbiota producing biologically relevant metabolites in multiple layers-biosynthetic pathways, host immunomodulatory functions and microbiome-level landscapes in the host.
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Remodeling of the Enterococcal Cell Envelope during Surface Penetration Promotes Intrinsic Resistance to Stress. mBio 2022; 13:e0229422. [PMID: 36354750 PMCID: PMC9765498 DOI: 10.1128/mbio.02294-22] [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] [Indexed: 11/12/2022] Open
Abstract
Enterococcus faecalis is a normal commensal of the human gastrointestinal tract (GIT). However, upon disruption of gut homeostasis, this nonmotile bacterium can egress from its natural niche and spread to distal organs. While this translocation process can lead to life-threatening systemic infections, the underlying mechanisms remain largely unexplored. Our prior work showed that E. faecalis migration across diverse surfaces requires the formation of matrix-covered multicellular aggregates and the synthesis of exopolysaccharides, but how enterococcal cells are reprogrammed during this process is unknown. Whether surface penetration endows E. faecalis with adaptive advantages is also uncertain. Here, we report that surface penetration promotes the generation of a metabolically and phenotypically distinct E. faecalis population with an enhanced capacity to endure various forms of extracellular stress. Surface-invading enterococci demonstrated major ultrastructural alterations in their cell envelope characterized by increased membrane glycolipid content. These changes were accompanied by marked induction of specific transcriptional programs enhancing cell envelope biogenesis and glycolipid metabolism. Notably, the surface-invading population demonstrated superior tolerance to membrane-damaging antimicrobials, including daptomycin and β-defensins produced by epithelial cells. Genetic mutations impairing glycolipid biosynthesis sensitized E. faecalis to envelope stressors and reduced the ability of this bacterium to penetrate semisolid surfaces and translocate through human intestinal epithelial cell monolayers. Our study reveals that surface penetration induces distinct transcriptional, metabolic, and ultrastructural changes that equip E. faecalis with enhanced capacity to resist external stressors and thrive in its surrounding environment. IMPORTANCE Enterococcus faecalis inhabits the GIT of multiple organisms, where its establishment could be mediated by the formation of biofilm-like aggregates. In susceptible individuals, this bacterium can overgrow and breach intestinal barriers, a process that may lead to lethal systemic infections. While the formation of multicellular aggregates promotes E. faecalis migration across surfaces, little is known about the metabolic and physiological states of the enterococci encased in these surface-penetrating structures. The present study reveals that E. faecalis cells capable of migrating through semisolid surfaces genetically reprogram their metabolism toward increased cell envelope and glycolipid biogenesis, which confers superior tolerance to membrane-damaging agents. E. faecalis's success as a pathobiont depends on its antimicrobial resistance, as well as on its rapid adaptability to overcome multiple environmental challenges. Thus, targeting adaptive genetic and/or metabolic pathways induced during E. faecalis surface penetration may be useful to better confront infections by this bacterium in the clinic.
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Meganathan Y, Vishwakarma A, Mohandass R. Biofilm formation and social interaction of Leptospira in natural and artificial environments. Res Microbiol 2022; 173:103981. [PMID: 35926730 DOI: 10.1016/j.resmic.2022.103981] [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: 06/06/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 10/16/2022]
Abstract
In the recent decades, there has been increased interest in the study on social interactions of pathogenic bacteria and biofilm-forming microbes. Leptospira is a zoonotic pathogen that causes human leptospirosis. Biofilm formation by pathogenic and saprophytic Leptospira has been documented in various biotic and abiotic environments. Biofilm supports cell growth and protects them from a variety of environmental stress. Pathogenic bacterial biofilm might increase the virulence and pathogenesis. However, research on the social behaviour and biofilm production by Leptospira is limited. This review discusses the interplay between the different species in the biofilm formation of saprophytic and pathogenic Leptospira and potential future applications.
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Affiliation(s)
- Yogesan Meganathan
- Molecular Genetics Laboratory, Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur 603203, Chengalapattu, TN, India
| | - Archana Vishwakarma
- Molecular Genetics Laboratory, Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur 603203, Chengalapattu, TN, India
| | - Ramya Mohandass
- Molecular Genetics Laboratory, Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur 603203, Chengalapattu, TN, India.
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Pang X, Wu Y, Liu X, Wu Y, Shu Q, Niu J, Chen Q, Zhang X. The Lipoteichoic Acid-Related Proteins YqgS and LafA Contribute to the Resistance of Listeria monocytogenes to Nisin. Microbiol Spectr 2022; 10:e0209521. [PMID: 35196823 PMCID: PMC8865564 DOI: 10.1128/spectrum.02095-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/24/2022] [Indexed: 11/20/2022] Open
Abstract
Listeria monocytogenes is a major pathogen contributing to foodborne outbreaks with high mortality. Nisin, a natural antimicrobial, has been widely used as a food preservative. However, the mechanisms of L. monocytogenes involved in nisin resistance have not yet to be fully defined. A mariner transposon library was constructed in L. monocytogenes, leading to the identification of 99 genes associated with the innate resistance to nisin via Transposon sequencing (Tn-seq) analysis. To validate the accuracy of the Tn-seq results, we constructed five mutants (ΔyqgS, ΔlafA, ΔvirR, ΔgtcA, and Δlmo1464) in L. monocytogenes. The results revealed that yqgS and lafA, the lipoteichoic acid-related genes, were essential for resistance to nisin, while the gtcA and lmo1464 mutants showed substantially enhanced nisin resistance. Densely wrinkled, collapsed surface and membrane breakdown were shown on ΔyqgS and ΔlafA mutants under nisin treatment. Deletion of yqgS and lafA altered the surface charge, and decreased the resistance to general stress conditions and cell envelope-acting antimicrobials. Furthermore, YqgS and LafA are required for biofilm formation and cell invasion of L. monocytogenes. Collectively, these results reveal novel mechanisms of nisin resistance in L. monocytogenes and may provide unique targets for the development of food-grade inhibitors for nisin-resistant foodborne pathogens. IMPORTANCE Listeria monocytogenes is an opportunistic Gram-positive pathogen responsible for listeriosis, and is widely present in a variety of foods including ready-to-eat foods, meat, and dairy products. Nisin is the only licensed lantibiotic by the FDA for use as a food-grade inhibitor in over 50 countries. A prior study suggests that L. monocytogenes are more resistant than other Gram-positive pathogens in nisin-mediated bactericidal effects. However, the mechanisms of L. monocytogenes involved in nisin resistance have not yet to be fully defined. Here, we used a mariner transposon library to identify nisin-resistance-related genes on a genome-wide scale via transposon sequencing. We found, for the first time, that YqgS and LafA (Lipoteichoic acid-related proteins) are required for resistance to nisin. Subsequently, we investigated the roles of YqgS and LafA in L. monocytogenes stress resistance, antimicrobial resistance, biofilm formation, and virulence in mammalian cells.
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Affiliation(s)
- Xinxin Pang
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, China
| | - Yansha Wu
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, China
| | - Xiayu Liu
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, China
| | - Yajing Wu
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, China
| | - Qin Shu
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, China
| | - Jianrui Niu
- College of Agriculture and Forestry, Linyi University, Linyi, China
| | - Qihe Chen
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, China
| | - Xinglin Zhang
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, China
- College of Agriculture and Forestry, Linyi University, Linyi, China
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Lin YC, Wu CY, Huang HT, Lu MK, Hu WS, Lee KT. Bacillus subtilis natto Derivatives Inhibit Enterococcal Biofilm Formation via Restructuring of the Cell Envelope. Front Microbiol 2021; 12:785351. [PMID: 34956152 PMCID: PMC8695906 DOI: 10.3389/fmicb.2021.785351] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/18/2021] [Indexed: 01/15/2023] Open
Abstract
Enterococcus faecalis is considered a leading cause of hospital-acquired infections. Treatment of these infections has become a major challenge for clinicians because some E. faecalis strains are resistant to multiple clinically used antibiotics. Moreover, the presence of E. faecalis biofilms can make infections with E. faecalis more difficult to eradicate with current antibiotic therapies. Thus, our aim in this study was to investigate the effects of probiotic derivatives against E. faecalis biofilm formation. Bacillus subtilis natto is a probiotic strain isolated from Japanese fermented soybean foods, and its culture fluid potently inhibited adherence to Caco-2 cell monolayers, aggregation, and biofilm production without inhibiting the growth of E. faecalis. An apparent decrease in the thickness of E. faecalis biofilms was observed through confocal laser scanning microscopy. In addition, exopolysaccharide synthesis in E. faecalis biofilms was reduced by B. subtilis natto culture fluid treatment. Carbohydrate composition analysis also showed that carbohydrates in the E. faecalis cell envelope were restructured. Furthermore, transcriptome sequencing revealed that the culture fluid of B. subtilis natto downregulated the transcription of genes involved in the WalK/WalR two-component system, peptidoglycan biosynthesis and membrane glycolipid biosynthesis, which are all crucial for E. faecalis cell envelope synthesis and biofilm formation. Collectively, our work shows that some derivatives present in the culture fluid of B. subtilis natto may be useful for controlling E. faecalis biofilms.
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Affiliation(s)
- Yu-Chieh Lin
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Chun-Yi Wu
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Hung-Tse Huang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan.,Ministry of Health and Welfare, National Research Institute of Chinese Medicine, Taipei, Taiwan
| | - Mei-Kuang Lu
- Ministry of Health and Welfare, National Research Institute of Chinese Medicine, Taipei, Taiwan.,Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan
| | - Wei-Shou Hu
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, United States
| | - Kung-Ta Lee
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan
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Basu N, Ghosh R. Recent chemical syntheses of bacteria related oligosaccharides using modern expeditious approaches. Carbohydr Res 2021; 507:108295. [PMID: 34271477 DOI: 10.1016/j.carres.2021.108295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/15/2021] [Accepted: 03/16/2021] [Indexed: 12/22/2022]
Abstract
Apart from some essential and crucial roles in life processes carbohydrates also are involved in a few detrimental courses of action related to human health, like infections by pathogenic microbes, cancer metastasis, transplanted tissue rejection, etc. Regarding management of pathogenesis by microbes, keeping in mind of multi drug-resistant bacteria and epidemic or endemic incidents, preventive measure by vaccination is the best pathway as also recommended by the WHO; by vaccination, eradication of bacterial diseases is also possible. Although some valid vaccines based on attenuated bacterial cells or isolated pure polysaccharide-antigens or the corresponding conjugates thereof are available in the market for prevention of several bacterial diseases, but these are not devoid of some disadvantages also. In order to develop improved conjugate T-cell dependent vaccines oligosaccharides related to bacterial antigens are synthesized and converted to the corresponding carrier protein conjugates. Marketed Cuban Quimi-Hib is such a vaccine being used since 2004 to resist Haemophilus influenza b infections. During nearly the past two decades research is going on worldwide for improved synthesis of bacteria related oligosaccharides or polysaccharides towards development of such semisynthetic or synthetic glycoconjugate vaccines. The present dissertation is an endeavour to encompass the recent syntheses of several pathogenic bacterial oligosaccharides or polysaccharides, made during the past ten-eleven years with special reference to modern expeditious syntheses.
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Affiliation(s)
- Nabamita Basu
- Department of Chemistry, Nabagram Hiralal Paul College, Konnagar, Hoogly, West Bengal, 712246, India
| | - Rina Ghosh
- Department of Chemistry, Jadavpur University, Kolkata, 700 032, India.
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12
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Janež N, Škrlj B, Sterniša M, Klančnik A, Sabotič J. The role of the Listeria monocytogenes surfactome in biofilm formation. Microb Biotechnol 2021; 14:1269-1281. [PMID: 34106516 PMCID: PMC8313260 DOI: 10.1111/1751-7915.13847] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 05/12/2021] [Accepted: 05/17/2021] [Indexed: 12/11/2022] Open
Abstract
Listeria monocytogenes is a highly pathogenic foodborne bacterium that is ubiquitous in the natural environment and capable of forming persistent biofilms in food processing environments. This species has a rich repertoire of surface structures that enable it to survive, adapt and persist in various environments and promote biofilm formation. We review current understanding and advances on how L. monocytogenes organizes its surface for biofilm formation on surfaces associated with food processing settings, because they may be an important target for development of novel antibiofilm compounds. A synthesis of the current knowledge on the role of Listeria surfactome, comprising peptidoglycan, teichoic acids and cell wall proteins, during biofilm formation on abiotic surfaces is provided. We consider indications gained from genome-wide studies and discuss surfactome structures with established mechanistic aspects in biofilm formation. Additionally, we look at the analogies to the species L. innocua, which is closely related to L. monocytogenes and often used as its model (surrogate) organism.
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Affiliation(s)
- Nika Janež
- Department of BiotechnologyJožef Stefan InstituteLjubljanaSlovenia
| | - Blaž Škrlj
- Department of Knowledge TechnologiesJožef Stefan InstituteLjubljanaSlovenia
- Jožef Stefan International Postgraduate SchoolLjubljanaSlovenia
| | - Meta Sterniša
- Department of Food Science and TechnologyBiotechnical FacultyUniversity of LjubljanaLjubljanaSlovenia
| | - Anja Klančnik
- Department of Food Science and TechnologyBiotechnical FacultyUniversity of LjubljanaLjubljanaSlovenia
| | - Jerica Sabotič
- Department of BiotechnologyJožef Stefan InstituteLjubljanaSlovenia
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13
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Woodall BM, Harp JR, Brewer WT, Tague ED, Campagna SR, Fozo EM. Enterococcus faecalis Readily Adapts Membrane Phospholipid Composition to Environmental and Genetic Perturbation. Front Microbiol 2021; 12:616045. [PMID: 34093456 PMCID: PMC8177052 DOI: 10.3389/fmicb.2021.616045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 04/15/2021] [Indexed: 11/22/2022] Open
Abstract
The bacterial lipid membrane, consisting both of fatty acid (acyl) tails and polar head groups, responds to changing conditions through alteration of either the acyl tails and/or head groups. This plasticity is critical for cell survival as it allows maintenance of both the protective nature of the membrane as well as functioning membrane protein complexes. Bacteria that live in fatty-acid rich environments, such as those found in the human host, can exploit host fatty acids to synthesize their own membranes, in turn, altering their physiology. Enterococcus faecalis is such an organism: it is a commensal of the mammalian intestine where it is exposed to fatty-acid rich bile, as well as a major cause of hospital infections during which it is exposed to fatty acid containing-serum. Within, we employed an untargeted approach to detect the most common phospholipid species of E. faecalis OG1RF via ultra-high performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS). We examined not only how the composition responds upon exposure to host fatty acids but also how deletion of genes predicted to synthesize major polar head groups impact lipid composition. Regardless of genetic background and differing basal lipid composition, all strains were able to alter their lipid composition upon exposure to individual host fatty acids. Specific gene deletion strains, however, had altered survival to membrane damaging agents. Combined, the enterococcal lipidome is highly resilient in response to both genetic and environmental perturbation, likely contributing to stress survival.
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Affiliation(s)
- Brittni M. Woodall
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - John R. Harp
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - William T. Brewer
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Eric D. Tague
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Shawn R. Campagna
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN, United States
- Biological and Small Molecule Mass Spectrometry Core, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Elizabeth M. Fozo
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
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14
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Artificial Sweeteners Negatively Regulate Pathogenic Characteristics of Two Model Gut Bacteria, E. coli and E. faecalis. Int J Mol Sci 2021; 22:ijms22105228. [PMID: 34063332 PMCID: PMC8156656 DOI: 10.3390/ijms22105228] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/11/2021] [Accepted: 05/13/2021] [Indexed: 12/11/2022] Open
Abstract
Artificial sweeteners (AS) are synthetic sugar substitutes that are commonly consumed in the diet. Recent studies have indicated considerable health risks which links the consumption of AS with metabolic derangements and gut microbiota perturbations. Despite these studies, there is still limited data on how AS impacts the commensal microbiota to cause pathogenicity. The present study sought to investigate the role of commonly consumed AS on gut bacterial pathogenicity and gut epithelium-microbiota interactions, using models of microbiota (Escherichia coli NCTC10418 and Enterococcus faecalis ATCC19433) and the intestinal epithelium (Caco-2 cells). Model gut bacteria were exposed to different concentrations of the AS saccharin, sucralose, and aspartame, and their pathogenicity and changes in interactions with Caco-2 cells were measured using in vitro studies. Findings show that sweeteners differentially increase the ability of bacteria to form a biofilm. Co-culture with human intestinal epithelial cells shows an increase in the ability of model gut bacteria to adhere to, invade and kill the host epithelium. The pan-sweet taste inhibitor, zinc sulphate, effectively blocked these negative impacts. Since AS consumption in the diet continues to increase, understanding how this food additive affects gut microbiota and how these damaging effects can be ameliorated is vital.
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15
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Mello SS, Van Tyne D, Lebreton F, Silva SQ, Nogueira MCL, Gilmore MS, Camargo ILBC. A mutation in the glycosyltransferase gene lafB causes daptomycin hypersusceptibility in Enterococcus faecium. J Antimicrob Chemother 2021; 75:36-45. [PMID: 31586422 DOI: 10.1093/jac/dkz403] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/26/2019] [Accepted: 08/23/2019] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVES To verify dissemination of daptomycin-non-susceptible Enterococcus faecium in a hospital where daptomycin was not in use and to understand the evolutionary pathways connecting daptomycin hypersusceptibility to non-susceptibility. METHODS Clonality of 26 E. faecium was assessed by PFGE and the STs of these isolates were determined. The most daptomycin-susceptible isolate was evolved in vitro by stepwise daptomycin selection, generating isolates for genome comparisons. RESULTS The spread of a high-risk daptomycin-non-susceptible VRE clone was detected, as was the occurrence of an unusual daptomycin-hypersusceptible strain (HBSJRP18). To determine the basis for daptomycin hypersusceptibility, we evolved HBSJRP18 in vitro and identified candidate genetic alterations potentially related to daptomycin susceptibility. Both lafB, encoding glycosyltransferase, which is putatively involved in lipoteichoic acid (LTA) biosynthesis, and dak, encoding a dihydroxyacetone kinase likely involved in fatty acid metabolism, were mutated in multiple independent experiments. Trans-complementation showed that the lafB polymorphism naturally occurring in HBSJRP18 caused its daptomycin hypersusceptibility. Fourier-transform infrared spectroscopy identified differences between the extracted LTA spectra from the hypersusceptible isolate and its revertant, as well as other non-susceptible variants, supporting a role for LafB in E. faecium LTA biosynthesis. Zeta potential difference was detected in one evolved dak mutant derivative. While much more susceptible to daptomycin, HBSJRP18 showed enhanced growth in the presence of piperacillin, suggesting that this, or another cell wall-targeting antibiotic, may have selected for the daptomycin-hypersusceptible phenotype. CONCLUSIONS Our findings provide new information on the basis for daptomycin susceptibility in E. faecium, with implications for limiting the development and spread of daptomycin resistance.
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Affiliation(s)
- Suelen S Mello
- Federal University of São Carlos, São Carlos, Brazil.,São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Daria Van Tyne
- Harvard Medical School, Boston, MA, USA.,Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Francois Lebreton
- Harvard Medical School, Boston, MA, USA.,Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Simone Q Silva
- Departamento de Doenças Dermatológicas, Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto - FAMERP, São José do Rio Preto, Brazil.,Instituto de Biociências, Letras e Ciências Exatas (IBILCE) - UNESP, São José do Rio Preto, Brazil
| | - Mara C L Nogueira
- Departamento de Doenças Dermatológicas, Infecciosas e Parasitárias, Faculdade de Medicina de São José do Rio Preto - FAMERP, São José do Rio Preto, Brazil
| | - Michael S Gilmore
- Harvard Medical School, Boston, MA, USA.,Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Ilana L B C Camargo
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
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16
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Agius JE, Phalen DN, Rose K, Eden JS. Genomic Insights Into the Pathogenicity of a Novel Biofilm-Forming Enterococcus sp. Bacteria ( Enterococcus lacertideformus) Identified in Reptiles. Front Microbiol 2021; 12:635208. [PMID: 33737921 PMCID: PMC7960928 DOI: 10.3389/fmicb.2021.635208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/09/2021] [Indexed: 11/23/2022] Open
Abstract
Whole genome analysis of a novel species of enterococci, Enterococcus lacertideformus, causing multi-systemic and invariably fatal disease in critically endangered Christmas Island reptiles was undertaken to determine the genetic elements and potential mechanisms conferring its pathogenic nature, biofilm-forming capabilities, immune recognition avoidance, and inability to grow in vitro. Comparative genomic analyses with related and clinically significant enterococci were further undertaken to infer the evolutionary history of the bacterium and identify genes both novel and absent. The genome had a G + C content of 35.1%, consisted of a circular chromosome, no plasmids, and was 2,419,934 bp in length (2,321 genes, 47 tRNAs, and 13 rRNAs). Multi-locus sequence typing (MLST), and single nucleotide polymorphism (SNP) analysis of multiple E. lacertideformus samples revealed they were effectively indistinguishable from one another and highly clonal. E. lacertideformus was found to be located within the Enterococcus faecium species clade and was closely related to Enterococcus villorum F1129D based on 16S rDNA and MLST house-keeping gene analysis. Antimicrobial resistance (DfreE, EfrB, tetM, bcrRABD, and sat4) and virulence genes (Fss3 and ClpP), and genes conferring tolerance to metals and biocides (n = 9) were identified. The detection of relatively few genes encoding antimicrobial resistance and virulence indicates that this bacterium may have had no exposure to recently developed and clinically significant antibiotics. Genes potentially imparting beneficial functional properties were identified, including prophages, insertion elements, integrative conjugative elements, and genomic islands. Functional CRISPR-Cas arrays, and a defective prophage region were identified in the genome. The study also revealed many genomic loci unique to E. lacertideformus which contained genes enriched in cell wall/membrane/envelop biogenesis, and carbohydrate metabolism and transport functionality. This finding and the detection of putative enterococcal biofilm determinants (EfaAfs, srtC, and scm) may underpin the novel biofilm phenotype observed for this bacterium. Comparative analysis of E. lacertideformus with phylogenetically related and clinically significant enterococci (E. villorum F1129D, Enterococcus hirae R17, E. faecium AUS0085, and Enterococcus faecalis OG1RF) revealed an absence of genes (n = 54) in E. lacertideformus, that encode metabolic functionality, which potentially hinders nutrient acquisition and/or utilization by the bacterium and precludes growth in vitro. These data provide genetic insights into the previously determined phenotype and pathogenic nature of the bacterium.
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Affiliation(s)
- Jessica Esther Agius
- Faculty of Science, Sydney School of Veterinary Science, University of Sydney, Camden, NSW, Australia
| | - David Norton Phalen
- Faculty of Science, Sydney School of Veterinary Science, University of Sydney, Camden, NSW, Australia.,Schubot Exotic Bird Health Center, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, United States
| | - Karrie Rose
- Australian Registry of Wildlife Health, Taronga Conservation Society Australia, Mosman, NSW, Australia
| | - John-Sebastian Eden
- Centre for Virus Research, The Westmead Institute for Medical Research, Westmead, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, Faculty of Medicine and Health, Sydney School of Medicine, University of Sydney, Camperdown, NSW, Australia
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17
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Yagami N, Vibhute AM, Tanaka HN, Komura N, Imamura A, Ishida H, Ando H. Stereoselective Synthesis of Diglycosyl Diacylglycerols with Glycosyl Donors Bearing a β-Stereodirecting 2,3-Naphthalenedimethyl Protecting Group. J Org Chem 2020; 85:16166-16181. [PMID: 33253577 DOI: 10.1021/acs.joc.0c02121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Diglycosyl diacylglycerols (DGDGs) are major components of Gram-positive bacterial plasma membranes and are involved in the immune response systems. The chemical synthesis of DGDGs has been highly demanded, as it will allow the elucidation of their biological functions at the molecular level. In this study, we have developed a novel β-stereodirecting 2,3-naphthalenedimethyl (NapDM) protecting group that is orthogonal to protecting groups commonly used in oligosaccharide synthesis. The NapDM group can be easily cleaved under TFA-mediated acidic conditions. Futhermore, we demonstrated the application of this protecting group to an acyl protecting-group-free strategy by utilizing the NapDM group for the synthesis of DGDGs. This strategy features the use of the β-stereodirecting NapDM group as an acid-cleavable permanent protecting group and late-stage glycosylation of monoglycosyl diacylglycerol acceptors, enabling the stereoselective synthesis of three different bacterial DGDGs with unsaturated fatty acid chain(s).
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Affiliation(s)
- Nahoko Yagami
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Amol M Vibhute
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Hide-Nori Tanaka
- Institute for Glyco-core Research (iGCORE), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.,Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Naoko Komura
- Institute for Glyco-core Research (iGCORE), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.,Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Akihiro Imamura
- Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Hideharu Ishida
- Institute for Glyco-core Research (iGCORE), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.,Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.,Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Hiromune Ando
- Institute for Glyco-core Research (iGCORE), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.,Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
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18
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Van Tyne D, Manson AL, Huycke MM, Karanicolas J, Earl AM, Gilmore MS. Impact of antibiotic treatment and host innate immune pressure on enterococcal adaptation in the human bloodstream. Sci Transl Med 2020; 11:11/487/eaat8418. [PMID: 30971455 DOI: 10.1126/scitranslmed.aat8418] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 11/10/2018] [Indexed: 12/11/2022]
Abstract
Multidrug-resistant enterococcal strains emerged in the early 1980s and are now among the leading causes of drug-resistant bacterial infection worldwide. We used functional genomics to study an early bacterial outbreak in patients in a Wisconsin hospital between 1984 and 1988 that was caused by multidrug-resistant Enterococcus faecalis The goal was to determine how a clonal lineage of E. faecalis became adapted to growth and survival in the human bloodstream. Genome sequence analysis revealed a progression of increasingly fixed mutations and repeated independent occurrences of mutations in a relatively small set of genes. Repeated independent mutations suggested selection within the host during the course of infection in response to pressures such as host immunity and antibiotic treatment. We observed repeated independent mutations in a small number of loci, including a little studied polysaccharide utilization pathway and the cydABDC locus. Functional studies showed that mutating these loci rendered E. faecalis better able to withstand antibiotic pressure and innate immune defenses in the human bloodstream. We also observed a shift in mutation pattern that corresponded to the introduction of carbapenem antibiotics in 1987. This work identifies pathways that allow enterococci to survive the transition from the human gut into the bloodstream, enabling them to cause severe bacteremia associated with high mortality.
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Affiliation(s)
- Daria Van Tyne
- Department of Ophthalmology and Department of Microbiology, Harvard Medical School, Boston, MA 02114, USA.,Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA.,Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
| | - Abigail L Manson
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
| | - Mark M Huycke
- Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - John Karanicolas
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Ashlee M Earl
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
| | - Michael S Gilmore
- Department of Ophthalmology and Department of Microbiology, Harvard Medical School, Boston, MA 02114, USA. .,Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA.,Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
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19
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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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20
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Spontaneously Arising Streptococcus mutans Variants with Reduced Susceptibility to Chlorhexidine Display Genetic Defects and Diminished Fitness. Antimicrob Agents Chemother 2019; 63:AAC.00161-19. [PMID: 31036688 DOI: 10.1128/aac.00161-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 04/20/2019] [Indexed: 01/10/2023] Open
Abstract
Chlorhexidine (CHX) has been used to control dental caries caused by acid-tolerant bacteria such as Streptococcus mutans since the 1970s. Repeat CHX exposure for other bacterial species results in the development of variants with reduced susceptibility that also become more resistant to other antimicrobials. It has not been tested if such variants arise when streptococci are exposed to CHX. Here, we passaged S. mutans in increasing concentrations of CHX and isolated spontaneously arising reduced susceptibility variants (RSVs) from separate lineages that have MICs that are up to 3-fold greater than the parental strain. The RSVs have increased growth rates at neutral pH and under acidic conditions in the presence of CHX but accumulate less biomass in biofilms. RSVs display higher MICs for daptomycin and clindamycin but increased sensitivity to dental-relevant antimicrobials triclosan and sodium fluoride. Plate-based assays for competition with health-associated oral streptococci revealed decreased bacteriocin production by the RSVs, increased sensitivity to hydrogen peroxide, and diminished competitive fitness in a human-derived ex vivo biofilm consortium. Whole-genome sequencing identified common single nucleotide polymorphisms (SNPs) within a diacylglycerol kinase homolog and a glycolipid synthesis enzyme, which could alter the accumulation of lipoteichoic acids and other envelope constituents, as well as a variety of mutations in other genes. Collectively, these findings confirm that S. mutans and likely other streptococci can develop tolerance to CHX but that increased tolerance comes at a fitness cost, such that CHX-induced variants that spontaneously arise in the human oral cavity may not persist.
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21
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Detection and characterization of bacterial polysaccharides in drug-resistant enterococci. Glycoconj J 2019; 36:429-438. [PMID: 31230165 DOI: 10.1007/s10719-019-09881-3] [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] [Received: 03/18/2019] [Revised: 03/18/2019] [Accepted: 06/17/2019] [Indexed: 01/26/2023]
Abstract
Enterococcus faecium (E. faecium) has emerged as one of today's leading causes of health care-associated infections that is difficult to treat with the available antibiotics. These pathogens produce capsular polysaccharides on the cell surface which play a significant role in adhesion, virulence and evasion. Therefore, we aimed at the identification and characterization of bacterial polysaccharide antigens which are central for the development of vaccine-based prophylactic approaches. The crude cell wall-associated polysaccharides from E. faecium, its mutant and complemented strains were purified and analyzed by a primary antibody raised against lipoteichoic acid (LTA) and diheteroglycan (DHG). The resistant E. faecium strains presumably possess novel capsular polysaccharides that allow them to avoid the evasion from opsonic killing. The E. faecium U0317 strain was very well opsonized by anti-U0317 (~95%), an antibody against the whole bacterial cell. The deletion mutant showed a significantly increased susceptibility to opsonophagocytic killing (90-95%) against the penicillin binding protein (anti-PBP-5). By comparison, in a mouse urinary tract and rat endocarditis infection model, respectively, there were no significant differences in virulence. In this study we explored the biological role of the capsule of E. faecium. Our findings showed that the U0317 strain is not only sensitive to anti-LTA but also to antibodies against other enterococcal surface proteins. Our findings demonstrate that polysaccharides capsule mediated-resistance to opsonophagocytosis. We also found that the capsular polysaccharides do not play an important role in bacterial virulence in urinary tract and infective endocarditis in vivo models.
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22
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Ch’ng JH, Chong KKL, Lam LN, Wong JJ, Kline KA. Biofilm-associated infection by enterococci. Nat Rev Microbiol 2018; 17:82-94. [DOI: 10.1038/s41579-018-0107-z] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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23
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Reduced Chlorhexidine and Daptomycin Susceptibility in Vancomycin-Resistant Enterococcus faecium after Serial Chlorhexidine Exposure. Antimicrob Agents Chemother 2017; 62:AAC.01235-17. [PMID: 29038276 PMCID: PMC5740357 DOI: 10.1128/aac.01235-17] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 10/10/2017] [Indexed: 12/22/2022] Open
Abstract
Vancomycin-resistant Enterococcus faecium strains (VREfm) are critical public health concerns because they are among the leading causes of hospital-acquired bloodstream infections. Chlorhexidine (CHX) is a bisbiguanide cationic antiseptic that is routinely used for patient bathing and other infection control practices. VREfm are likely frequently exposed to CHX; however, the long-term effects of CHX exposure have not been studied in enterococci. In this study, we serially exposed VREfm to increasing concentrations of CHX for a period of 21 days in two independent experimental evolution trials. Reduced CHX susceptibility emerged (4-fold shift in CHX MIC). Subpopulations with reduced daptomycin (DAP) susceptibility were detected, which were further analyzed by genome sequencing and lipidomic analysis. Across the trials, we identified adaptive changes in genes with predicted or experimentally confirmed roles in chlorhexidine susceptibility (efrE), global nutritional stress response (relA), nucleotide metabolism (cmk), phosphate acquisition (phoU), and glycolipid biosynthesis (bgsB), among others. Moreover, significant alterations in membrane phospholipids were identified for some populations with reduced DAP susceptibility. Our results are clinically significant because they identify a link between serial subinhibitory CHX exposure and reduced DAP susceptibility. In addition, the CHX-induced genetic and lipidomic changes described in this study offer new insights into the mechanisms underlying the emergence of antibiotic resistance in VREfm.
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24
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Goh HMS, Yong MHA, Chong KKL, Kline KA. Model systems for the study of Enterococcal colonization and infection. Virulence 2017; 8:1525-1562. [PMID: 28102784 PMCID: PMC5810481 DOI: 10.1080/21505594.2017.1279766] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/30/2016] [Accepted: 01/04/2017] [Indexed: 02/07/2023] Open
Abstract
Enterococcus faecalis and Enterococcus faecium are common inhabitants of the human gastrointestinal tract, as well as frequent opportunistic pathogens. Enterococci cause a range of infections including, most frequently, infections of the urinary tract, catheterized urinary tract, bloodstream, wounds and surgical sites, and heart valves in endocarditis. Enterococcal infections are often biofilm-associated, polymicrobial in nature, and resistant to antibiotics of last resort. Understanding Enterococcal mechanisms of colonization and pathogenesis are important for identifying new ways to manage and intervene with these infections. We review vertebrate and invertebrate model systems applied to study the most common E. faecalis and E. faecium infections, with emphasis on recent findings examining Enterococcal-host interactions using these models. We discuss strengths and shortcomings of each model, propose future animal models not yet applied to study mono- and polymicrobial infections involving E. faecalis and E. faecium, and comment on the significance of anti-virulence strategies derived from a fundamental understanding of host-pathogen interactions in model systems.
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Affiliation(s)
- H. M. Sharon Goh
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - M. H. Adeline Yong
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kelvin Kian Long Chong
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate School, 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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Miller WR, Murray BE, Rice LB, Arias CA. Vancomycin-Resistant Enterococci: Therapeutic Challenges in the 21st Century. Infect Dis Clin North Am 2017; 30:415-439. [PMID: 27208766 DOI: 10.1016/j.idc.2016.02.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Vancomycin-resistant enterococci are serious health threats due in part to their ability to persist in rugged environments and their propensity to acquire antibiotic resistance determinants. Enterococci have now established a home in our hospitals and possess mechanisms to defeat most currently available antimicrobials. This article reviews the history of the struggle with this pathogen, what is known about the traits associated with its rise in the modern medical environment, and the current understanding of therapeutic approaches in severe infections caused by these microorganisms. As the 21st century progresses, vancomycin-resistant enterococci continue to pose a daunting clinical challenge.
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Affiliation(s)
- William R Miller
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Barbara E Murray
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA; Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Louis B Rice
- Departments of Medicine, Microbiology and Immunology, Warren Alpert Medical School of Brown University, 593 Eddy Street, Providence, RI 02903, USA
| | - Cesar A Arias
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA; Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA; Molecular Genetics and Antimicrobial Resistance Unit, International Center for Microbial Genomics, Universidad El Bosque, Avenue Cra 9 No. 131 A - 02, Bogotá, Colombia.
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Bacterial size matters: Multiple mechanisms controlling septum cleavage and diplococcus formation are critical for the virulence of the opportunistic pathogen Enterococcus faecalis. PLoS Pathog 2017; 13:e1006526. [PMID: 28742152 PMCID: PMC5542707 DOI: 10.1371/journal.ppat.1006526] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 08/03/2017] [Accepted: 07/12/2017] [Indexed: 12/02/2022] Open
Abstract
Enterococcus faecalis is an opportunistic pathogen frequently isolated in clinical settings. This organism is intrinsically resistant to several clinically relevant antibiotics and can transfer resistance to other pathogens. Although E. faecalis has emerged as a major nosocomial pathogen, the mechanisms underlying the virulence of this organism remain elusive. We studied the regulation of daughter cell separation during growth and explored the impact of this process on pathogenesis. We demonstrate that the activity of the AtlA peptidoglycan hydrolase, an enzyme dedicated to septum cleavage, is controlled by several mechanisms, including glycosylation and recognition of the peptidoglycan substrate. We show that the long cell chains of E. faecalis mutants are more susceptible to phagocytosis and are no longer able to cause lethality in the zebrafish model of infection. Altogether, this work indicates that control of cell separation during division underpins the pathogenesis of E. faecalis infections and represents a novel enterococcal virulence factor. We propose that inhibition of septum cleavage during division represents an attractive therapeutic strategy to control infections. Enterococcus faecalis is a commensal bacterium that colonizes the gastrointestinal tract of humans. This organism is an opportunistic pathogen that can cause a wide range of life-threatening infections in hospital settings. Despite the identification of several virulence factors, the mechanisms by which E. faecalis evades host immunity and causes infections remains poorly understood. Here, we explore how the formation of diplococci and short cell chains, a distinctive property of E. faecalis, contributes to pathogenesis. We describe several mechanisms that control the activity of AtlA, the enzyme dedicated to septum cleavage during division. Using a combination of in vitro assays and flow cytometry analyses of E. faecalis mutants, we show that AtlA activity is regulated by several mechanisms. We reveal that during pathogenesis, AtlA activity is critical for overcoming the host immune response. In the absence of AtlA, the long cell chains of E. faecalis mutants are more susceptible to phagocytosis and can no longer cause lethality in the zebrafish model of infection, thus indicating that control of cell chain length is a novel virulence factor in E. faecalis. This work highlights a link between cell division and pathogenesis and suggests that cell separation represents a step that can be targeted to control bacterial infections.
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Transcriptome Sequencing Reveals Wide Expression Reprogramming of Basal and Unknown Genes in Leptospira biflexa Biofilms. mSphere 2016; 1:mSphere00042-16. [PMID: 27303713 PMCID: PMC4863578 DOI: 10.1128/msphere.00042-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 03/11/2016] [Indexed: 11/20/2022] Open
Abstract
In this work, we describe the first transcriptome based on RNA-seq technology focused on studying transcriptional changes associated with biofilm growth in a member of the genus Leptospira. As many pathogenic species of this genus can survive inside the host but also persist in environmental water, mostly forming biofilms, identifying the molecular basis of this capacity can impact the understanding of how leptospires are able to fulfill a complete life cycle that alternates between adaptation to the host and adaptation to hostile external environmental conditions. We identified several genes and regulatory networks that can be the kickoff for deepening understanding of the molecular mechanisms involving bacterial persistence via biofilm formation; understanding this is important for the future development of tools for controlling leptospirosis. The genus Leptospira is composed of pathogenic and saprophytic spirochetes. Pathogenic Leptospira is the etiological agent of leptospirosis, a globally spread neglected disease. A key ecological feature of some pathogenic species is their ability to survive both within and outside the host. For most leptospires, the ability to persist outside the host is associated with biofilm formation, a most important bacterial strategy to face and overcome hostile environmental conditions. The architecture and biochemistry of leptospiral biofilms are rather well understood; however, the genetic program underpinning biofilm formation remains mostly unknown. In this work, we used the saprophyte Leptospira biflexa as a model organism to assess over- and underrepresented transcripts during the biofilm state, using transcriptome sequencing (RNA-seq) technology. Our results showed that some basal biological processes like DNA replication and cell division are downregulated in the mature biofilm. Additionally, we identified significant expression reprogramming for genes involved in motility, sugar/lipid metabolism, and iron scavenging, as well as for outer membrane-encoding genes. A careful manual annotation process allowed us to assign molecular functions to many previously uncharacterized genes that are probably involved in biofilm metabolism. We also provided evidence for the presence of small regulatory RNAs in this species. Finally, coexpression networks were reconstructed to pinpoint functionally related gene clusters that may explain how biofilm maintenance is regulated. Beyond elucidating some genetic aspects of biofilm formation, this work reveals a number of pathways whose functional dissection may impact our understanding of leptospiral biology, in particular how these organisms adapt to environmental changes. IMPORTANCE In this work, we describe the first transcriptome based on RNA-seq technology focused on studying transcriptional changes associated with biofilm growth in a member of the genus Leptospira. As many pathogenic species of this genus can survive inside the host but also persist in environmental water, mostly forming biofilms, identifying the molecular basis of this capacity can impact the understanding of how leptospires are able to fulfill a complete life cycle that alternates between adaptation to the host and adaptation to hostile external environmental conditions. We identified several genes and regulatory networks that can be the kickoff for deepening understanding of the molecular mechanisms involving bacterial persistence via biofilm formation; understanding this is important for the future development of tools for controlling leptospirosis.
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Diederich AK, Duda KA, Romero-Saavedra F, Engel R, Holst O, Huebner J. Deletion of fabN in Enterococcus faecalis results in unsaturated fatty acid auxotrophy and decreased release of inflammatory cytokines. Innate Immun 2016; 22:284-93. [PMID: 27009913 DOI: 10.1177/1753425916639669] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 02/17/2016] [Indexed: 01/09/2023] Open
Abstract
The Gram-positive bacterium Enterococcus faecalis can cause life-threatening infections and is resistant to several commonly used antibiotics. The type II fatty acid pathway in bacteria is discussed as a potential target for antimicrobial therapy. However, it was shown that inhibition or deletion of its enzymes can be rescued in Gram-positive bacteria by supplementation with fatty acids. Here we show that by deletion of the fabN gene, which is essential for unsaturated fatty acid (UFA) synthesis in E. faecalis, growth is impaired but can be rescued by supplementation with oleic acid or human serum. Nonetheless, we demonstrate alterations of the UFA profile after supplementation with oleic acid in the ΔfabN mutant using a specific glycolipid. In addition, we demonstrate that cytokine release in vitro is almost abolished after stimulation of mouse macrophages by the mutant in comparison to the wild type. The results indicate that fabN is not a suitable target for antimicrobials as UFA auxotrophy can be overcome. However, deletion of fabN resulted in a decreased inflammatory response indicating that fabN and resulting UFA synthesis are relevant for virulence.
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Affiliation(s)
- Ann-Kristin Diederich
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany Division of Pediatric Infectious Diseases, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany Department of Microbiology, Faculty of Biology, Albert-Ludwigs-University, Freiburg, Germany
| | - Katarzyna A Duda
- Division of Structural Biochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Priority Area Asthma & Allergy, Research Center Borstel, Airway Research Center North (ARCN), Member of the German Center for Lung Research (DZL), D-23845 Borstel, Germany
| | - Felipe Romero-Saavedra
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany 2EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Regina Engel
- Division of Structural Biochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Priority Area Asthma & Allergy, Research Center Borstel, Airway Research Center North (ARCN), Member of the German Center for Lung Research (DZL), D-23845 Borstel, Germany
| | - Otto Holst
- Division of Structural Biochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Priority Area Asthma & Allergy, Research Center Borstel, Airway Research Center North (ARCN), Member of the German Center for Lung Research (DZL), D-23845 Borstel, Germany
| | - Johannes Huebner
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany Division of Pediatric Infectious Diseases, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
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Raven KE, Reuter S, Gouliouris T, Reynolds R, Russell JE, Brown NM, Török ME, Parkhill J, Peacock SJ. Genome-based characterization of hospital-adapted Enterococcus faecalis lineages. Nat Microbiol 2016; 1:15033. [PMID: 27213049 PMCID: PMC4872833 DOI: 10.1038/nmicrobiol.2015.33] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 12/24/2015] [Indexed: 11/09/2022]
Abstract
Vancomycin-resistant Enterococcus faecalis (VREfs) is an important nosocomial pathogen1,2. We undertook whole genome sequencing of E. faecalis associated with bloodstream infection in the UK and Ireland over more than a decade to determine the population structure and genetic associations with hospital adaptation. Three lineages predominated in the population, two of which (L1 and L2) were nationally distributed, and one (L3) geographically restricted. Genome comparison with a global collection identified that L1 and L3 were also present in the USA, but were genetically distinct. Over 90% of VREfs belonged to L1-L3, with resistance acquired and lost multiple times in L1 and L2, but only once followed by clonal expansion in L3. Putative virulence and antibiotic resistance genes were over-represented in L1, L2 and L3 isolates combined, versus the remainder. Each of the three main lineages contained a mixture of vancomycin-resistant and -susceptible E. faecalis (VSEfs), which has important implications for infection control and antibiotic stewardship.
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Affiliation(s)
- Kathy E. Raven
- Department of Medicine, University of Cambridge, Box 157 Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Sandra Reuter
- Department of Medicine, University of Cambridge, Box 157 Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Theodore Gouliouris
- Department of Medicine, University of Cambridge, Box 157 Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0QQ, UK
- Clinical Microbiology and Public Health Laboratory, Public Health England, Box 236, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0QQ, UK
- Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge CB2 0QQ, UK
| | - Rosy Reynolds
- British Society for Antimicrobial Chemotherapy, Griffin House, 53 Regent Place, Birmingham B1 3NJ, UK
- North Bristol NHS Trust, Southmead Hospital, Bristol, BS10 5NB, UK
| | - Julie E. Russell
- Culture Collections, Public Health England, Porton Down, Salisbury SP4 0JG, UK
| | - Nicholas M. Brown
- Clinical Microbiology and Public Health Laboratory, Public Health England, Box 236, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0QQ, UK
- British Society for Antimicrobial Chemotherapy, Griffin House, 53 Regent Place, Birmingham B1 3NJ, UK
| | - M. Estée Török
- Department of Medicine, University of Cambridge, Box 157 Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0QQ, UK
- Clinical Microbiology and Public Health Laboratory, Public Health England, Box 236, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0QQ, UK
- Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge CB2 0QQ, UK
| | - Julian Parkhill
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Sharon J. Peacock
- Department of Medicine, University of Cambridge, Box 157 Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0QQ, UK
- Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge CB2 0QQ, UK
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
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Valero-Guillén PL, Fernández-Natal I, Marrodán-Ciordia T, Tauch A, Soriano F. Ether-linked lipids of Dermabacter hominis, a human skin actinobacterium. Chem Phys Lipids 2016; 196:24-32. [PMID: 26867985 DOI: 10.1016/j.chemphyslip.2016.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 10/22/2022]
Abstract
Dermabacter hominis is a medically important actinobacterial inhabitant of human skin, although it is rarely implicated in infections. The lipid composition of D. hominis is revisited in this study in the context of its natural resistance to daptomycin, an antibiotic whose activity is influenced by membrane lipids. Thin layer chromatography and mass spectrometry revealed that this species contains phospholipids and glycolipids. Using electrospray ionization time of flight mass spectrometry (exact mass) and gas chromatography-mass spectrometry, the major phospholipid of D. hominis was identified as plasmanyl-phosphatidylglycerol (pPG), because it presented one alkyl chain and one acyl chain in the glycerol moiety of the molecule. The structure of the major glycolipid (GL1) was studied by combined gas-liquid chromatography, mass spectrometry and nuclear magnetic resonance, and was established as galactosyl-α-(1→2)-glucosyl-alkyl-acyl-glycerol. Lipid analyses showed differences between one daptomycin-resistant (DAP-R) strain and one daptomycin-sensitive (DAP-S) strain growing in the presence of the antibiotic: DAP-R tended to accumulate GL1 and to reduce pPG, whereas DAP-S maintained high proportions of pPG. The results demonstrate the existence of ether-linked lipids in D. hominis and reveal a differential distribution of phospholipids and glycolipids according to the sensitivity or resistance to daptomycin, although the mechanism(s) operating in the resistance to the antibiotic remain(s) to be elucidated.
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Affiliation(s)
- Pedro L Valero-Guillén
- Departamento de Genética y Microbiología, Facultad de Medicina, Universidad de Murcia, Spain; Instituto Murciano de Investigación Biosanitaria (IMIB), Spain.
| | - Isabel Fernández-Natal
- Departamento de Microbiología Clínica, Complejo Asistencial Universitario de León-Sacyl, León, Spain; Instituto de Biomedicina (IBIOMED), Universidad de León, León, Spain
| | - Teresa Marrodán-Ciordia
- Departamento de Microbiología Clínica, Complejo Asistencial Universitario de León-Sacyl, León, Spain
| | - Andreas Tauch
- Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie (CeBiTec), Universität Bielefeld, Bielefeld, Germany
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Romero-Saavedra F, Laverde D, Budin-Verneuil A, Muller C, Bernay B, Benachour A, Hartke A, Huebner J. Characterization of Two Metal Binding Lipoproteins as Vaccine Candidates for Enterococcal Infections. PLoS One 2015; 10:e0136625. [PMID: 26322633 PMCID: PMC4556446 DOI: 10.1371/journal.pone.0136625] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 08/05/2015] [Indexed: 12/19/2022] Open
Abstract
Background Enterococcus faecium and faecalis are Gram-positive opportunistic pathogens that have become leading causes of nosocomial infections over the last decades. Especially multidrug resistant enterococci have become a challenging clinical problem worldwide. Therefore, new treatment options are needed and the identification of alternative targets for vaccine development has emerged as a feasible alternative to fight the infections caused by these pathogens. Results We extrapolate the transcriptomic data from a mice peritonitis infection model in E. faecalis to identify putative up-regulated surface proteins under infection conditions in E. faecium. After the bionformatic analyses two metal binding lipoproteins were identified to have a high homology (>72%) between the two species, the manganese ABC transporter substrate-binding lipoprotein (PsaAfm,) and the zinc ABC transporter substrate-binding lipoprotein (AdcAfm). These candidate lipoproteins were overexpressed in Escherichia coli and purified. The recombinant proteins were used to produce rabbit polyclonal antibodies that were able to induce specific opsonic antibodies that mediated killing of the homologous strain E. faecium E155 as well as clinical strains E. faecium E1162, Enterococcus faecalis 12030, type 2 and type 5. Mice were passively immunized with the antibodies raised against recombinant lipoproteins, showing significant reduction of colony counts in mice livers after the bacterial challenge and demonstrating the efficacy of these metal binding lipoproteins as promising vaccine candidates to treat infections caused by these enterococcal pathogens. Conclusion Overall, our results demonstrate that these two metal binding lipoproteins elicited specific, opsonic and protective antibodies, with an extensive cross-reactivity and serotype-independent coverage among these two important nocosomial pathogens. Pointing these two protein antigens as promising immunogens, that can be used as single components or as carrier proteins together with polysaccharide antigens in vaccine development against enterococcal infections.
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Affiliation(s)
- Felipe Romero-Saavedra
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Diana Laverde
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | | | - Cécile Muller
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Benoit Bernay
- Proteogen platform SFR ICORE 4206, University of Caen Lower-Normandy, Caen, France
| | - Abdellah Benachour
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Axel Hartke
- EA4655 U2RM Stress/Virulence, University of Caen Lower-Normandy, Caen, France
| | - Johannes Huebner
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Freiburg, Germany
- Division of Pediatric Infectious Diseases, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
- * E-mail:
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Bitoun JP, Wen ZT. Transcription factor Rex in regulation of pathophysiology in oral pathogens. Mol Oral Microbiol 2015; 31:115-24. [PMID: 26172563 DOI: 10.1111/omi.12114] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/29/2015] [Indexed: 11/29/2022]
Abstract
The NAD(+) and NADH-sensing transcriptional regulator Rex is widely conserved across gram-positive bacteria. Rex monitors cellular redox poise and controls the expression of genes/operons involved in diverse pathways including alternative fermentation, oxidative stress responses, and biofilm formation. The oral cavity undergoes frequent and drastic fluctuations in nutrient availability, pH, temperature, oxygen tension, saliva, and shear forces. The oral streptococci are major colonizers of oral mucosa and tooth surfaces and include commensals as well as opportunistic pathogens, including the primary etiological agent of dental caries, Streptococcus mutans. Current understanding of the Rex regulon in oral bacteria is mostly based on studies in S. mutans and endodontic pathogen Enterococcus faecalis. Indeed, other oral bacteria encode homologs of the Rex protein and much is to be gleaned from more in-depth studies. Our current understanding has Rex positioned at the interface of oxygen and energy metabolism. In biofilms, heterogeneous oxygen tension influences the ratio of intracellular NADH and NAD(+) , which is finely tuned through glycolysis and fermentation. In S. mutans, Rex regulates the expression of glycolytic enzyme NAD(+) -dependent glyceraldehyde 3-phosphate dehydrogenase, and NADH-dependent fermentation enzymes/complexes lactate dehydrogenase, pyruvate dehydrogenase, alcohol-acetaldehyde dehydrogenase, and fumarate reductase. In addition, Rex controls the expression of NADH oxidase, a major enzyme used to eliminate oxidative stress and regenerate NAD(+) . Here, we summarize recent studies carried out on the Rex regulators in S. mutans and E. faecalis. This research has important implications for understanding how Rex monitors redox balance and optimizes fermentation pathways for survival and subsequent pathogenicity.
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Affiliation(s)
- J P Bitoun
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Z T Wen
- Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, New Orleans, LA, USA.,Center of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA, USA.,Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, USA
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Theilacker C, Diederich AK, Otto A, Sava IG, Wobser D, Bao Y, Hese K, Broszat M, Henneke P, Becher D, Huebner J. Enterococcus faecalis Glycolipids Modulate Lipoprotein-Content of the Bacterial Cell Membrane and Host Immune Response. PLoS One 2015; 10:e0132949. [PMID: 26172831 PMCID: PMC4501811 DOI: 10.1371/journal.pone.0132949] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 06/21/2015] [Indexed: 12/25/2022] Open
Abstract
In this study, we investigated the impact of the cell membrane composition of E. faecalis on its recognition by the host immune system. To this end, we employed an E. faecalis deletion mutant (ΔbgsA) that does not synthesize the major cell membrane glycolipid diglycosyl-diacylglycerol (DGlcDAG). Proteomic analysis revealed that 13 of a total of 21 upregulated surface-associated proteins of E. faecalis ΔbgsA were lipoproteins. This led to a total lipoprotein content in the cell membrane of 35.8% in ΔbgsA compared to only 9.4% in wild-type bacteria. Increased lipoprotein content strongly affected the recognition of ΔbgsA by mouse macrophages in vitro with an increased stimulation of TNF-α production by heat-fixed bacteria and secreted antigens. Inactivation of the prolipoprotein diacylglycerol transferase (lgt) in ΔbgsA abrogated TNF-α induction by a ΔbgsA_lgt double mutant indicating that lipoproteins mediate increased activation of mouse macrophages by ΔbgsA. Heat-fixed ΔbgsA bacteria, culture supernatant, or cell membrane lipid extract activated transfected HEK cells in a TLR2-dependent fashion; the same was not true of wild-type bacteria. In mice infected intraperitoneally with a sublethal dose of E. faecalis we observed a 70% greater mortality in mice infected with ΔbgsA compared with wild-type-infected mice. Increased mortality due to ΔbgsA infection was associated with elevated plasma levels of the inflammatory cytokines TNF-α, IL-6 and MIP-2. In summary, our results provide evidence that an E. faecalis mutant lacking its major bilayer forming glycolipid DGlcDAG upregulates lipoprotein expression leading to increased activation of the host innate immune system and virulence in vivo.
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Affiliation(s)
- Christian Theilacker
- Center for Chronic Immunodeficiency (CCI), University Medical Center Freiburg, Freiburg, Germany
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany
- * E-mail:
| | - Ann-Kristin Diederich
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany
- Division of Pediatric Infectious Diseases, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
- Department of Microbiology, Faculty of Biology, Albert-Ludwigs-University, Freiburg, Germany
| | - Andreas Otto
- Institute for Microbiology, Department of Microbial Physiology, Ernst-Moritz-Arndt-University, Greifswald, Germany
| | - Irina G. Sava
- Research Center for Nutrition and Food Science, Technical University Munich, Freising, Germany
| | - Dominique Wobser
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Yinyin Bao
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Katrin Hese
- Center for Chronic Immunodeficiency (CCI), University Medical Center Freiburg, Freiburg, Germany
| | - Melanie Broszat
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Philipp Henneke
- Center for Chronic Immunodeficiency (CCI), University Medical Center Freiburg, Freiburg, Germany
- Center for Paediatrics and Adolescent Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Dörte Becher
- Institute for Microbiology, Department of Microbial Physiology, Ernst-Moritz-Arndt-University, Greifswald, Germany
| | - Johannes Huebner
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Freiburg, Germany
- Division of Pediatric Infectious Diseases, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
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Zischka M, Künne CT, Blom J, Wobser D, Sakιnç T, Schmidt-Hohagen K, Dabrowski PW, Nitsche A, Hübner J, Hain T, Chakraborty T, Linke B, Goesmann A, Voget S, Daniel R, Schomburg D, Hauck R, Hafez HM, Tielen P, Jahn D, Solheim M, Sadowy E, Larsen J, Jensen LB, Ruiz-Garbajosa P, Quiñones Pérez D, Mikalsen T, Bender J, Steglich M, Nübel U, Witte W, Werner G. Comprehensive molecular, genomic and phenotypic analysis of a major clone of Enterococcus faecalis MLST ST40. BMC Genomics 2015; 16:175. [PMID: 25887115 PMCID: PMC4374294 DOI: 10.1186/s12864-015-1367-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 02/20/2015] [Indexed: 11/28/2022] Open
Abstract
Background Enterococcus faecalis is a multifaceted microorganism known to act as a beneficial intestinal commensal bacterium. It is also a dreaded nosocomial pathogen causing life-threatening infections in hospitalised patients. Isolates of a distinct MLST type ST40 represent the most frequent strain type of this species, distributed worldwide and originating from various sources (animal, human, environmental) and different conditions (colonisation/infection). Since enterococci are known to be highly recombinogenic we determined to analyse the microevolution and niche adaptation of this highly distributed clonal type. Results We compared a set of 42 ST40 isolates by assessing key molecular determinants, performing whole genome sequencing (WGS) and a number of phenotypic assays including resistance profiling, formation of biofilm and utilisation of carbon sources. We generated the first circular closed reference genome of an E. faecalis isolate D32 of animal origin and compared it with the genomes of other reference strains. D32 was used as a template for detailed WGS comparisons of high-quality draft genomes of 14 ST40 isolates. Genomic and phylogenetic analyses suggest a high level of similarity regarding the core genome, also demonstrated by similar carbon utilisation patterns. Distribution of known and putative virulence-associated genes did not differentiate between ST40 strains from a commensal and clinical background or an animal or human source. Further analyses of mobile genetic elements (MGE) revealed genomic diversity owed to: (1) a modularly structured pathogenicity island; (2) a site-specifically integrated and previously unknown genomic island of 138 kb in two strains putatively involved in exopolysaccharide synthesis; and (3) isolate-specific plasmid and phage patterns. Moreover, we used different cell-biological and animal experiments to compare the isolate D32 with a closely related ST40 endocarditis isolate whose draft genome sequence was also generated. D32 generally showed a greater capacity of adherence to human cell lines and an increased pathogenic potential in various animal models in combination with an even faster growth in vivo (not in vitro). Conclusion Molecular, genomic and phenotypic analysis of representative isolates of a major clone of E. faecalis MLST ST40 revealed new insights into the microbiology of a commensal bacterium which can turn into a conditional pathogen. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1367-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Melanie Zischka
- Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855, Wernigerode, Germany. .,Present address: Institute for Pathology, Hannover Medical School (MHH), Hannover, Germany.
| | - Carsten T Künne
- Functional Genomics of Bacterial Pathogens, Institute for Medical Microbiology, Justus Liebig University Giessen and German Center for Infection Research (DZIF), Partner site Giessen-Marburg-Langen, Campus Giessen, Giessen, Germany. .,Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.
| | - Jochen Blom
- Center for Biotechnology (CeBiTec)/University of Bielefeld, Bielefeld, Germany. .,Institute for Bioinformatics and Systems Biology, Justus Liebig University Giessen, Giessen, Germany.
| | - Dominique Wobser
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg, Germany.
| | - Türkân Sakιnç
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg, Germany.
| | - Kerstin Schmidt-Hohagen
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig, Germany.
| | - P Wojtek Dabrowski
- Robert Koch Institute, ZBS 1 Highly Pathogenic Viruses, Centre for Biological Threats and Special Pathogens, Berlin, Germany.
| | - Andreas Nitsche
- Robert Koch Institute, ZBS 1 Highly Pathogenic Viruses, Centre for Biological Threats and Special Pathogens, Berlin, Germany.
| | - Johannes Hübner
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg, Germany. .,Division of Pediatric Infectious Diseases, Hauner Children's Hospital, Ludwig-Maximilians University Munich, Munich, Germany.
| | - Torsten Hain
- Functional Genomics of Bacterial Pathogens, Institute for Medical Microbiology, Justus Liebig University Giessen and German Center for Infection Research (DZIF), Partner site Giessen-Marburg-Langen, Campus Giessen, Giessen, Germany.
| | - Trinad Chakraborty
- Functional Genomics of Bacterial Pathogens, Institute for Medical Microbiology, Justus Liebig University Giessen and German Center for Infection Research (DZIF), Partner site Giessen-Marburg-Langen, Campus Giessen, Giessen, Germany.
| | - Burkhard Linke
- Center for Biotechnology (CeBiTec)/University of Bielefeld, Bielefeld, Germany. .,Institute for Bioinformatics and Systems Biology, Justus Liebig University Giessen, Giessen, Germany.
| | - Alexander Goesmann
- Center for Biotechnology (CeBiTec)/University of Bielefeld, Bielefeld, Germany. .,Institute for Bioinformatics and Systems Biology, Justus Liebig University Giessen, Giessen, Germany.
| | - Sonja Voget
- Goettingen Genomics Laboratory, Georg August University, Goettingen, Germany.
| | - Rolf Daniel
- Goettingen Genomics Laboratory, Georg August University, Goettingen, Germany.
| | - Dietmar Schomburg
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Braunschweig, Germany.
| | - Rüdiger Hauck
- Department of Veterinary Medicine, Institute for Poultry Diseases, Free University Berlin, Berlin, Germany.
| | - Hafez M Hafez
- Department of Veterinary Medicine, Institute for Poultry Diseases, Free University Berlin, Berlin, Germany.
| | - Petra Tielen
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.
| | - Dieter Jahn
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.
| | - Margrete Solheim
- Laboratory of Microbial Gene Technology and Food Microbiology, The Norwegian University of Life Sciences, Ås, Norway.
| | - Ewa Sadowy
- National Medicines Institute, Warsaw, Poland.
| | | | - Lars B Jensen
- Division of Microbiology, National Food Institute, Danish Technical University, Copenhagen, Denmark.
| | | | - Dianelys Quiñones Pérez
- Instituto de Medicina Tropical Pedro Kourí, Servicio de Bacteriología-Micología, La Habana, Cuba.
| | - Theresa Mikalsen
- Department of Medical Biology, Faculty of Health Sciences, Research Group for Host Microbe Interactions, University of Tromsø, Tromsø, Norway.
| | - Jennifer Bender
- Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855, Wernigerode, Germany.
| | - Matthias Steglich
- Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855, Wernigerode, Germany.
| | - Ulrich Nübel
- Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855, Wernigerode, Germany. .,Leibniz-Institut DSMZ - Deutsche Sammlung von Mikrorganismen und Zellkulturen GmbH, Braunschweig, Germany.
| | - Wolfgang Witte
- Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855, Wernigerode, Germany.
| | - Guido Werner
- Division of Nosocomial Pathogens and Antibiotic Resistances, Department of Infectious Diseases, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855, Wernigerode, Germany.
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Rossmann FS, Racek T, Wobser D, Puchalka J, Rabener EM, Reiger M, Hendrickx APA, Diederich AK, Jung K, Klein C, Huebner J. Phage-mediated dispersal of biofilm and distribution of bacterial virulence genes is induced by quorum sensing. PLoS Pathog 2015; 11:e1004653. [PMID: 25706310 PMCID: PMC4338201 DOI: 10.1371/journal.ppat.1004653] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/02/2015] [Indexed: 01/10/2023] Open
Abstract
The microbiome and the phage meta-genome within the human gut are influenced by antibiotic treatments. Identifying a novel mechanism, here we demonstrate that bacteria use the universal communication molecule AI-2 to induce virulence genes and transfer them via phage release. High concentrations (i.e. 100 μM) of AI-2 promote dispersal of bacteria from already established biofilms, and is associated with release of phages capable of infecting other bacteria. Enterococcus faecalis V583ΔABC harbours 7 prophages in its genome, and a mutant deficient in one of these prophages (i.e. prophage 5) showed a greatly reduced dispersal of biofilm. Infection of a probiotic E. faecalis strain without lytic prophages with prophage 5 resulted in increased biofilm formation and also in biofilm dispersal upon induction with AI-2. Infection of the probiotic E. faecalis strain with phage-containing supernatants released through AI-2 from E. faecalis V583ΔABC resulted in a strong increase in pathogenicity of this strain. The polylysogenic probiotic strain was also more virulent in a mouse sepsis model and a rat endocarditis model. Both AI-2 and ciprofloxacin lead to phage release, indicating that conditions in the gastrointestinal tract of hospitalized patients treated with antibiotics might lead to distribution of virulence genes to apathogenic enterococci and possibly also to other commensals or even to beneficial probiotic strains. All higher organisms live in intimate contact with bacteria and viruses in their direct environment. Some of these bacteria in our gut can switch between being harmless commensals and causing severe and sometimes lethal infections. This involves a tight regulation of the mechanisms needed to initially colonize and later to harm the host. Here we describe a novel mechanism by which phages (i.e. viruses that infect bacteria) contribute to virulence in commensal gut bacteria. Our results show that bacteria "sense" the number of bacteria present at any given moment through a process called quorum sensing and this provides them with the information needed to assess the specific step during the infectious process. At late stages of infection bacteria are usually present in high numbers, and at this point release viruses that can infect nearby bacteria and transfer genes that are needed to cause infection, thereby enabling previously harmless bacteria to become dangerous pathogens.
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Affiliation(s)
- Friederike S. Rossmann
- Division of Infectious Diseases, Department of Medicine, University Hospital, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University, Freiburg, Germany
- Department of Pediatrics, Dr. von Hauner Children´s Hospital, Ludwig-Maximilians University of Munich, Munich, Germany
| | - Tomas Racek
- Department of Pediatrics, Dr. von Hauner Children´s Hospital, Ludwig-Maximilians University of Munich, Munich, Germany
- German Center for Infection Research (DZIF), Partnersite Munich, Munich, Germany
| | - Dominique Wobser
- Division of Infectious Diseases, Department of Medicine, University Hospital, Freiburg, Germany
| | - Jacek Puchalka
- Department of Pediatrics, Dr. von Hauner Children´s Hospital, Ludwig-Maximilians University of Munich, Munich, Germany
- German Center for Infection Research (DZIF), Partnersite Munich, Munich, Germany
| | - Elaine M. Rabener
- Department of Biology I, Microbiology, Munich Center for Integrated Protein Science, Ludwig-Maximilians University of Munich, Munich, Germany
| | - Matthias Reiger
- Department of Biology I, Microbiology, Munich Center for Integrated Protein Science, Ludwig-Maximilians University of Munich, Munich, Germany
| | | | - Ann-Kristin Diederich
- Division of Infectious Diseases, Department of Medicine, University Hospital, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University, Freiburg, Germany
- Department of Pediatrics, Dr. von Hauner Children´s Hospital, Ludwig-Maximilians University of Munich, Munich, Germany
| | - Kirsten Jung
- Department of Biology I, Microbiology, Munich Center for Integrated Protein Science, Ludwig-Maximilians University of Munich, Munich, Germany
| | - Christoph Klein
- Department of Pediatrics, Dr. von Hauner Children´s Hospital, Ludwig-Maximilians University of Munich, Munich, Germany
- German Center for Infection Research (DZIF), Partnersite Munich, Munich, Germany
| | - Johannes Huebner
- Division of Infectious Diseases, Department of Medicine, University Hospital, Freiburg, Germany
- Department of Pediatrics, Dr. von Hauner Children´s Hospital, Ludwig-Maximilians University of Munich, Munich, Germany
- German Center for Infection Research (DZIF), Partnersite Munich, Munich, Germany
- * E-mail:
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Rossmann FS, Laverde D, Kropec A, Romero-Saavedra F, Meyer-Buehn M, Huebner J. Isolation of highly active monoclonal antibodies against multiresistant gram-positive bacteria. PLoS One 2015; 10:e0118405. [PMID: 25706415 PMCID: PMC4338075 DOI: 10.1371/journal.pone.0118405] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Accepted: 01/15/2015] [Indexed: 11/18/2022] Open
Abstract
Multiresistant nosocomial pathogens often cause life-threatening infections that are sometimes untreatable with currently available antibiotics. Staphylococci and enterococci are the predominant Gram-positive species associated with hospital-acquired infections. These infections often lead to extended hospital stay and excess mortality. In this study, a panel of fully human monoclonal antibodies was isolated from a healthy individual by selection of B-cells producing antibodies with high opsonic killing against E. faecalis 12030. Variable domains (VH and VL) of these immunoglobulin genes were amplified by PCR and cloned into an eukaryotic expression vector containing the constant domains of a human IgG1 molecule and the human lambda constant domain. These constructs were transfected into CHO cells and culture supernatants were collected and tested by opsonophagocytic assay against E. faecalis and S. aureus strains (including MRSA). At concentrations of 600 pg/ml, opsonic killing was between 40% and 70% against all strains tested. Monoclonal antibodies were also evaluated in a mouse sepsis model (using S. aureus LAC and E. faecium), a mouse peritonitis model (using S. aureus Newman and LAC) and a rat endocarditis model (using E. faecalis 12030) and were shown to provide protection in all models at a concentration of 4 μg/kg per animal. Here we present a method to produce fully human IgG1 monoclonal antibodies that are opsonic in vitro and protective in vivo against several multiresistant Gram-positive bacteria. The monoclonal antibodies presented in this study are significantly more effective compared to another monoclonal antibody currently in clinical trials.
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Affiliation(s)
- Friederike S. Rossmann
- Department of Medicine, Division of Infectious Diseases, University Hospital, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University, Freiburg, Germany
- Department of Pediatrics, Dr. von Hauner Children’s Hospital, Ludwig-Maximilians University, Munich, Germany
- German Center of Infection Research (DZIF), Partnersite Munich, Germany
- * E-mail:
| | - Diana Laverde
- Department of Medicine, Division of Infectious Diseases, University Hospital, Freiburg, Germany
| | - Andrea Kropec
- Department of Medicine, Division of Infectious Diseases, University Hospital, Freiburg, Germany
| | - Felipe Romero-Saavedra
- Department of Medicine, Division of Infectious Diseases, University Hospital, Freiburg, Germany
| | - Melanie Meyer-Buehn
- Department of Pediatrics, Dr. von Hauner Children’s Hospital, Ludwig-Maximilians University, Munich, Germany
- German Center of Infection Research (DZIF), Partnersite Munich, Germany
| | - Johannes Huebner
- Department of Medicine, Division of Infectious Diseases, University Hospital, Freiburg, Germany
- Department of Pediatrics, Dr. von Hauner Children’s Hospital, Ludwig-Maximilians University, Munich, Germany
- German Center of Infection Research (DZIF), Partnersite Munich, Germany
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37
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Rossmann FS, Kropec A, Laverde D, Saaverda FR, Wobser D, Huebner J. In vitro and in vivo activity of hyperimmune globulin preparations against multiresistant nosocomial pathogens. Infection 2014; 43:169-75. [PMID: 25428225 PMCID: PMC4382538 DOI: 10.1007/s15010-014-0706-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 11/13/2014] [Indexed: 11/25/2022]
Abstract
Purpose We compared different immunoglobulin preparations containing IgG (Intraglobin/Intratect) or a mixture of IgG, IgA, and IgM (Pentaglobin) to assess the opsonic and protective efficacy of human immunoglobulin preparations against multiresistent nosocomial pathogens. Materials and methods Clinical isolates of E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecalis, Enterococcus faecium, and Staphylococcus aureus were tested by opsonophagocytic assay using immunologobulin preparations at dilutions usually obtained in patients. The target antigens of opsonic antibodies were characterized by opsonophagocytic inhibition assays, and the protective efficacy in vivo was tested in a mouse bacteremia model as previously described. Results All strains were killed to at least 50 % by Pentaglobin. One P. aeruginosa strain was not efficiently killed by Intraglobin (23 %) but the other strains were killed by Intraglobin to a similar degree compared to Pentaglobin. Opsonic IgG antibodies against E. faecalis were directed against LTA, while opsonic antibodies in Pentaglobin were primarily directed against other cell wall carbohydrates. In a mouse bacteremia model, Pentaglobin was more protective than Intratect against Staphylococcus aureus, while Intratect reduced colony counts better than normal rabbit serum or saline. Conclusions All tested human immunoglobulin preparations contain opsonic and protective antibodies against targets present on multiresistant Gram-positive and Gram-negative bacteria. Enrichment of these preparations with IgM increases the protective efficacy against some strains, probably due to antibodies directed against cell wall carbohydrates.
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Affiliation(s)
- F. S. Rossmann
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg im Breisgau, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg University, Freiburg im Breisgau, Germany
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Dr. von Hauner Children’s Hospital, Ludwig-Maximilians University, Munich, Germany
- German Center for Infection Research (DZIF), Partnersite Munich, Munich, Germany
| | - A. Kropec
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg im Breisgau, Germany
- German Center for Infection Research (DZIF), Partnersite Munich, Munich, Germany
| | - D. Laverde
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg im Breisgau, Germany
- German Center for Infection Research (DZIF), Partnersite Munich, Munich, Germany
| | - F. R. Saaverda
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg im Breisgau, Germany
- German Center for Infection Research (DZIF), Partnersite Munich, Munich, Germany
| | - D. Wobser
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg im Breisgau, Germany
- German Center for Infection Research (DZIF), Partnersite Munich, Munich, Germany
| | - J. Huebner
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg im Breisgau, Germany
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Dr. von Hauner Children’s Hospital, Ludwig-Maximilians University, Munich, Germany
- German Center for Infection Research (DZIF), Partnersite Munich, Munich, Germany
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38
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Ge C, Gómez-Llobregat J, Skwark MJ, Ruysschaert JM, Wieslander A, Lindén M. Membrane remodeling capacity of a vesicle-inducing glycosyltransferase. FEBS J 2014; 281:3667-84. [PMID: 24961908 DOI: 10.1111/febs.12889] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/21/2014] [Accepted: 06/19/2014] [Indexed: 11/28/2022]
Abstract
Intracellular vesicles are abundant in eukaryotic cells but absent in the Gram-negative bacterium Escherichia coli. However, strong overexpression of a monotopic glycolipid-synthesizing enzyme, monoglucosyldiacylglycerol synthase from Acholeplasma laidlawii (alMGS), leads to massive formation of vesicles in the cytoplasm of E. coli. More importantly, alMGS provides a model system for the regulation of membrane properties by membrane-bound enzymes, which is critical for maintaining cellular integrity. Both phenomena depend on how alMGS binds to cell membranes, which is not well understood. Here, we carry out a comprehensive investigation of the membrane binding of alMGS by combining bioinformatics methods with extensive biochemical studies, structural modeling and molecular dynamics simulations. We find that alMGS binds to the membrane in a fairly upright manner, mainly by residues in the N-terminal domain, and in a way that induces local enrichment of anionic lipids and a local curvature deformation. Furthermore, several alMGS variants resulting from substitution of residues in the membrane anchoring segment are still able to generate vesicles, regardless of enzymatic activity. These results clarify earlier theories about the driving forces for vesicle formation, and shed new light on the membrane binding properties and enzymatic mechanism of alMGS and related monotopic GT-B fold glycosyltransferases.
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Affiliation(s)
- Changrong Ge
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, Sweden; Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, Belgium; Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
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Diederich AK, Wobser D, Spiess M, Sava IG, Huebner J, Sakιnç T. Role of glycolipids in the pathogenesis of Enterococcus faecalis urinary tract infection. PLoS One 2014; 9:e96295. [PMID: 24806450 PMCID: PMC4012979 DOI: 10.1371/journal.pone.0096295] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 04/06/2014] [Indexed: 01/28/2023] Open
Abstract
Background After uropathogenic Escherichia coli (UPEC), Enterococcus faecalis is the second most common pathogen causing urinary tract infections. Monoglucosyl-diacylglycerol (MGlcDAG) and diglucosyl-diacylglycerol (DGlcDAG) are the main glycolipids of the E. faecalis cell membrane. Examination of two mutants in genes bgsB and bgsA (both glycosyltransferases) showed that these genes are involved in cell membrane glycolipid biosynthesis, and that their inactivation leads to loss of glycolipids DGlcDAG (bgsA) or both MGlcDAG and DGlcDAG (bgsB). Here we investigate the function of bgsB and bgsA regarding their role in the pathogenesis in a mouse model of urinary tract infection and in bacterial adhesion to T24 bladder epithelial cells. Results In a mouse model of urinary tract infection, we showed that E. faecalis 12030ΔbgsB and E. faecalis 12030ΔbgsA mutants, colonize uroepithelial surfaces more efficiently than wild-type bacteria. We also demonstrated that these mutants showed a more than three-fold increased binding to human bladder carcinoma cells line T24 compared to the wild-type strain. Bacterial binding could be specifically inhibited by purified glycolipids. Lipoteichoic acid (LTA), wall-teichoic acid (WTA), and glycosaminoglycans (GAGs) were not significantly involved in binding of E. faecalis to the bladder epithelial cell line. Conclusions Our data show that the deletion of bgsB and bgsA and the absence of the major glycolipid diglucosyl-diacylglycerol increases colonization and binding to uroepithelial cells. We hypothesize that secreted diglucosyl-diacylglycerol blocks host binding sites, thereby preventing bacterial adhesion. Further experiments will be needed to clarify the exact mechanism underlying the adhesion through glycolipids and their cognate receptors.
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Affiliation(s)
| | - Dominique Wobser
- Division of Infectious Diseases, University Hospital Freiburg, Freiburg, Germany
| | - Meike Spiess
- Division of Infectious Diseases, University Hospital Freiburg, Freiburg, Germany
| | - Irina G. Sava
- Nutrition and Immunology, Research Centre for Nutrition and Food Science, Technical University Munich, Munich, Germany
| | - Johannes Huebner
- Division of Infectious Diseases, University Hospital Freiburg, Freiburg, Germany
- Division of Pediatric Infectious Diseases, Dr. Von Hauner Children's Hospital, Ludwig Maximilian University Munich, Munich, Germany
- * E-mail:
| | - Türkân Sakιnç
- Division of Infectious Diseases, University Hospital Freiburg, Freiburg, Germany
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40
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Reichmann NT, Piçarra Cassona C, Monteiro JM, Bottomley AL, Corrigan RM, Foster SJ, Pinho MG, Gründling A. Differential localization of LTA synthesis proteins and their interaction with the cell division machinery in Staphylococcus aureus. Mol Microbiol 2014; 92:273-86. [PMID: 24533796 PMCID: PMC4065355 DOI: 10.1111/mmi.12551] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2014] [Indexed: 11/28/2022]
Abstract
Lipoteichoic acid (LTA) is an important cell wall component of Gram-positive bacteria. In Staphylococcus aureus it consists of a polyglycerolphosphate-chain that is retained within the membrane via a glycolipid. Using an immunofluorescence approach, we show here that the LTA polymer is not surface exposed in S. aureus, as it can only be detected after digestion of the peptidoglycan layer. S. aureus mutants lacking LTA are enlarged and show aberrant positioning of septa, suggesting a link between LTA synthesis and the cell division process. Using a bacterial two-hybrid approach, we show that the three key LTA synthesis proteins, YpfP and LtaA, involved in glycolipid production, and LtaS, required for LTA backbone synthesis, interact with one another. All three proteins also interacted with numerous cell division and peptidoglycan synthesis proteins, suggesting the formation of a multi-enzyme complex and providing further evidence for the co-ordination of these processes. When assessed by fluorescence microscopy, YpfP and LtaA fluorescent protein fusions localized to the membrane while the LtaS enzyme accumulated at the cell division site. These data support a model whereby LTA backbone synthesis proceeds in S. aureus at the division site in co-ordination with cell division, while glycolipid synthesis takes place throughout the membrane.
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Affiliation(s)
- Nathalie T Reichmann
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College LondonLondon, SW7 2AZ, UK
| | - Carolina Piçarra Cassona
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College LondonLondon, SW7 2AZ, UK
| | - João M Monteiro
- Instituto de Technologia Química e Biológica, Universidade Nova de LisboaOeiras, Portugal
| | - Amy L Bottomley
- The Krebs Institute, Department of Molecular Biology and Biotechnology, University of SheffieldSheffield, UK
| | - Rebecca M Corrigan
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College LondonLondon, SW7 2AZ, UK
| | - Simon J Foster
- The Krebs Institute, Department of Molecular Biology and Biotechnology, University of SheffieldSheffield, UK
| | - Mariana G Pinho
- Instituto de Technologia Química e Biológica, Universidade Nova de LisboaOeiras, Portugal
| | - Angelika Gründling
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College LondonLondon, SW7 2AZ, UK
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Cell-wall glycolipid mutations and their effects on virulence of E. faecalis in a rat model of infective endocarditis. PLoS One 2014; 9:e91863. [PMID: 24637922 PMCID: PMC3956713 DOI: 10.1371/journal.pone.0091863] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 02/17/2014] [Indexed: 11/19/2022] Open
Abstract
Enterococci are among the major pathogens implicated in cardiac infections and biofilm formation. E. faecalis has been shown to play an important role in infectious endocarditis. Several distinct mechanisms for biofilm formation have been identified in E. faecalis. Our group has previously characterized two distinct bacterial glucosyltransferases playing key roles in the production of the major cell wall glycolipids and leading to reduced biofilm production. To assess if this mechanism is involved in the pathogenesis of enterococcal endocarditis we compared the wild-type strain of E. faecalis 12030 with two mutants in gene EF2891 and EF2890 respectively in a rat model of infective endocarditis. The results showed less endocarditic lesions and reduced colony counts per vegetation in the two mutants. indicating that the modification of bacterial surface lipids results in significantly reduced virulence in infective endocarditis. These results underscore the important role of biofilm formation in the pathogenicity of enterococcal endocarditis and may indicate an interesting target for novel therapeutic strategies.
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Meiers M, Volz C, Eisel J, Maurer P, Henrich B, Hakenbeck R. Altered lipid composition in Streptococcus pneumoniae cpoA mutants. BMC Microbiol 2014; 14:12. [PMID: 24443834 PMCID: PMC3901891 DOI: 10.1186/1471-2180-14-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 01/16/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Penicillin-resistance in Streptococcus pneumoniae is mainly due to alterations in genes encoding the target enzymes for beta-lactams, the penicillin-binding proteins (PBPs). However, non-PBP genes are altered in beta-lactam-resistant laboratory mutants and confer decreased susceptibility to beta-lactam antibiotics. Two piperacillin resistant laboratory mutants of Streptococcus pneumoniae R6 contain mutations in the putative glycosyltransferase gene cpoA. The CpoA gene is part of an operon including another putative glycosyltransferase gene spr0982, both of which being homologous to glycolipid synthases present in other Gram-positive bacteria. RESULTS We now show that the cpoA mutants as well as a cpoA deletion mutant are defective in the synthesis of galactosyl-glucosyl-diacylglycerol (GalGlcDAG) in vivo consistent with the in vitro function of CpoA as α-GalGlcDAG synthase as shown previously. In addition, the proportion of phosphatidylglycerol increased relative to cardiolipin in cpoA mutants. Moreover, cpoA mutants are more susceptible to acidic stress, have an increased requirement for Mg(2+) at low pH, reveal a higher resistance to lysis inducing conditions and are hypersensitive to bacitracin. CONCLUSIONS The data show that deficiency of the major glycolipid GalGlcDAG causes a pleitotropic phenotype of cpoA mutant cells consistent with severe membrane alterations. We suggest that the cpoA mutations selected with piperacillin are directed against the lytic response induced by the beta-lactam antibiotic.
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Affiliation(s)
| | | | | | | | | | - Regine Hakenbeck
- Department of Microbiology, University of Kaiserslautern, Gottlieb-Daimler-Strasse, Gebäude 23, D-67663 Kaiserslautern, Germany.
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Bacterial cell wall macroamphiphiles: Pathogen-/microbe-associated molecular patterns detected by mammalian innate immune system. Biochimie 2013; 95:33-42. [DOI: 10.1016/j.biochi.2012.06.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 06/06/2012] [Indexed: 02/02/2023]
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Pedrido ME, de Oña P, Ramirez W, Leñini C, Goñi A, Grau R. Spo0A links de novo fatty acid synthesis to sporulation and biofilm development in Bacillus subtilis. Mol Microbiol 2012; 87:348-67. [PMID: 23170957 DOI: 10.1111/mmi.12102] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2012] [Indexed: 11/25/2022]
Abstract
During sporulation in Bacillus subtilis, the committed-cell undergoes substantial membrane rearrangements to generate two cells of different sizes and fates: the mother cell and the forespore. Here, we demonstrate that the master transcription factor Spo0A reactivates lipid synthesis during development. Maximal Spo0A-dependent lipid synthesis occurs during the key stages of asymmetric division and forespore engulfment. Spo0A reactivates the accDA operon that encodes the carboxylase component of the acetyl-CoA carboxylase enzyme, which catalyses the first and rate-limiting step in de novo lipid biosynthesis, malonyl-CoA formation. The disruption of the Spo0A-binding box in the promoter region of accDA impairs its transcriptional reactivation and blocks lipid synthesis. The Spo0A-insensitive accDA(0A) cells were proficient in planktonic growth but defective in sporulation (σ(E) activation) and biofilm development (cell cluster formation and water repellency). Exogenous fatty acid supplementation to accDA(0A) cells overcomes their inability to synthesize lipids during development and restores sporulation and biofilm proficiencies. The transient exclusion of the lipid synthesis regulon from the forespore and the known compartmentalization of Spo0A and ACP in the mother cell suggest that de novo lipid synthesis is confined to the mother cell. The significance of the Spo0A-controlled de novo lipid synthesis during B. subtilis development is discussed.
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Affiliation(s)
- María E Pedrido
- Departamento de Microbiología, Universidad Nacional de Rosario, CONICET, Argentina
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Bao Y, Sakinc T, Laverde D, Wobser D, Benachour A, Theilacker C, Hartke A, Huebner J. Role of mprF1 and mprF2 in the pathogenicity of Enterococcus faecalis. PLoS One 2012; 7:e38458. [PMID: 22723861 PMCID: PMC3377626 DOI: 10.1371/journal.pone.0038458] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 05/05/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Enterococcus faecalis is one of the leading causes of nosocomial infections. Due to its innate and acquired resistance to most antibiotics, identification of new targets for antimicrobial treatment of E. faecalis is a high priority. The multiple peptide resistance factor MprF, which was first described in Staphylococcus aureus, modifies phosphatidylglycerol with lysin and reduces the negative charge of the membrane, thus increasing resistance to cationic antimicrobial peptides. We studied the effect of mprF in E. faecalis regarding influence on bacterial physiology and virulence. RESULTS Two putative mprF paralogs (mprF1 and mprF2) were identified in E. faecalis by BLAST search using the well-described S. aureus gene as a lead. Two deletion mutants in E. faecalis 12030 were created by homologous recombination. Analysis of both mutants by thin-layer chromatography showed that inactivation of mprF2 abolishes the synthesis of three distinct amino-phosphatidylglycerols (PGs). In contrast, deletion of mprF1 did not interfere with the biosynthesis of amino-PG. Inactivation of mprF2 increased susceptibility against several antimicrobial peptides and resulted in a 42% increased biofilm formation compared to wild-type mprF. However, resistance to opsonic killing was increased in the mutant, while virulence in a mouse bacteremia model was unchanged. CONCLUSION Our data suggest that only mprF2 is involved in the aminoacylation of PG in enterococci, and is probably responsible for synthesis of Lys-PG, Ala-PG, and Arg-PG, while mprF1 does not seem to have a role in aminoacylation. As in other Gram-positive pathogens, aminoacylation through MprF2 increases resistance against cationic antimicrobial peptides. Unlike mprF found in other bacteria, mprF2 does not seem to be a major virulence factor in enterococci.
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Affiliation(s)
- Yinyin Bao
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg, Germany
- EA4655 U2RM Stress/Virulence, Université de Caen Basse-Normandie, Caen, France
| | - Tuerkan Sakinc
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Diana Laverde
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Dominique Wobser
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Abdellah Benachour
- EA4655 U2RM Stress/Virulence, Université de Caen Basse-Normandie, Caen, France
| | - Christian Theilacker
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Axel Hartke
- EA4655 U2RM Stress/Virulence, Université de Caen Basse-Normandie, Caen, France
| | - Johannes Huebner
- Division of Infectious Diseases, Department of Medicine, University Hospital Freiburg, Freiburg, Germany
- * E-mail:
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Abstract
The genus Enterococcus includes some of the most important nosocomial multidrug-resistant organisms, and these pathogens usually affect patients who are debilitated by other, concurrent illnesses and undergoing prolonged hospitalization. This Review discusses the factors involved in the changing epidemiology of enterococcal infections, with an emphasis on Enterococcus faecium as an emergent and challenging nosocomial problem. The effects of antibiotics on the gut microbiota and on colonization with vancomycin-resistant enterococci are highlighted, including how enterococci benefit from the antibiotic-mediated eradication of gram-negative members of the gut microbiota. Analyses of enterococcal genomes indicate that there are certain genetic lineages, including an E. faecium clade of ancient origin, with the ability to succeed in the hospital environment, and the possible virulence determinants that are found in these genetic lineages are discussed. Finally, we review the most important mechanisms of resistance to the antibiotics that are used to treat vancomycin-resistant enterococci.
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Tatituri RVV, Brenner MB, Turk J, Hsu FF. Structural elucidation of diglycosyl diacylglycerol and monoglycosyl diacylglycerol from Streptococcus pneumoniae by multiple-stage linear ion-trap mass spectrometry with electrospray ionization. JOURNAL OF MASS SPECTROMETRY : JMS 2012; 47:115-23. [PMID: 22282097 PMCID: PMC3712276 DOI: 10.1002/jms.2033] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The cell wall of the pathogenic bacterium Streptococcus pneumoniae contains glucopyranosyl diacylglycerol (GlcDAG) and galactoglucopyranosyldiacylglycerol (GalGlcDAG). The specific GlcDAG consisting of vaccenic acid substituent at sn-2 was recently identified as another glycolipid antigen family recognized by invariant natural killer T-cells. Here, we describe a linear ion-trap multiple-stage (MS(n) ) mass spectrometric approach towards structural analysis of GalGlcDAG and GlcDAG. Structural information derived from MS(n) (n = 2, 3) on the [M + Li](+) adduct ions desorbed by electrospray ionization affords identification of the fatty acid substituents, assignment of the fatty acyl groups on the glycerol backbone, as well as the location of double bond along the fatty acyl chain. The identification of the fatty acyl groups and determination of their regio-specificity were confirmed by MS(n) (n = 2, 3) on the [M + NH(4) ](+) ions. We establish the structures of GalGlcDAG and GlcDAG isolated from S. pneumoniae, in which the major species consists of a 16:1- or 18:1-fatty acid substituent mainly at sn-2, and the double bond of the fatty acid is located at ω-7 (n-7). More than one isomers were found for each mass in the family. This mass spectrometric approach provides a simple method to achieve structure identification of this important lipid family that would be very difficult to define using the traditional method.
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Affiliation(s)
- Raju Venkata Veera Tatituri
- Division of Rheumatology, Immunology, and Allergy, Brigham and Women’s Hospital, Harvard Medical School, 1 Jimmy Fund Way, Boston, Massachusetts 02115
| | - Michael B. Brenner
- Division of Rheumatology, Immunology, and Allergy, Brigham and Women’s Hospital, Harvard Medical School, 1 Jimmy Fund Way, Boston, Massachusetts 02115
| | - John Turk
- Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism, and Lipid research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Fong-Fu Hsu
- Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism, and Lipid research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110
- To whom the correspondence should be addressed: Dr. Fong-Fu Hsu, Box 8127, Washington University School of Medicine, 660 S Euclid, St. Louis, MO 63110. Tel: 314-362-0056,
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Large-scale screening of a targeted Enterococcus faecalis mutant library identifies envelope fitness factors. PLoS One 2011; 6:e29023. [PMID: 22194979 PMCID: PMC3240637 DOI: 10.1371/journal.pone.0029023] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 11/18/2011] [Indexed: 11/25/2022] Open
Abstract
Spread of antibiotic resistance among bacteria responsible for nosocomial and community-acquired infections urges for novel therapeutic or prophylactic targets and for innovative pathogen-specific antibacterial compounds. Major challenges are posed by opportunistic pathogens belonging to the low GC% Gram-positive bacteria. Among those, Enterococcus faecalis is a leading cause of hospital-acquired infections associated with life-threatening issues and increased hospital costs. To better understand the molecular properties of enterococci that may be required for virulence, and that may explain the emergence of these bacteria in nosocomial infections, we performed the first large-scale functional analysis of E. faecalis V583, the first vancomycin-resistant isolate from a human bloodstream infection. E. faecalis V583 is within the high-risk clonal complex 2 group, which comprises mostly isolates derived from hospital infections worldwide. We conducted broad-range screenings of candidate genes likely involved in host adaptation (e.g., colonization and/or virulence). For this purpose, a library was constructed of targeted insertion mutations in 177 genes encoding putative surface or stress-response factors. Individual mutants were subsequently tested for their i) resistance to oxidative stress, ii) antibiotic resistance, iii) resistance to opsonophagocytosis, iv) adherence to the human colon carcinoma Caco-2 epithelial cells and v) virulence in a surrogate insect model. Our results identified a number of factors that are involved in the interaction between enterococci and their host environments. Their predicted functions highlight the importance of cell envelope glycopolymers in E. faecalis host adaptation. This study provides a valuable genetic database for understanding the steps leading E. faecalis to opportunistic virulence.
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Paganelli FL, Willems RJ, Leavis HL. Optimizing future treatment of enterococcal infections: attacking the biofilm? Trends Microbiol 2011; 20:40-9. [PMID: 22169461 DOI: 10.1016/j.tim.2011.11.001] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 10/19/2011] [Accepted: 11/02/2011] [Indexed: 11/16/2022]
Abstract
Enterococcus faecalis and Enterococcus faecium are among the leading causative agents of nosocomial infections and are infamous for their resistance to many antibiotics. They cause difficult-to-treat infections, often originating from biofilm-mediated infections associated with implanted medical devices or endocarditis. Biofilms protect bacteria against antibiotics and phagocytosis, and physical removal of devices or infected tissue is often needed but is frequently not possible. Currently there are no clinically available compounds that disassemble biofilms. In this review we discuss all known structural and regulatory genes involved in enterococcal biofilm formation, the compounds directed against biofilm formation that have been studied, and potentially useful targets for future drugs to treat enterococcal biofilm-associated infections.
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Affiliation(s)
- Fernanda L Paganelli
- Department of Medical Microbiology, University Medical Center Utrecht, The Netherlands
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Kropec A, Sava IG, Vonend C, Sakinc T, Grohmann E, Huebner J. Identification of SagA as a novel vaccine target for the prevention of Enterococcus faecium infections. Microbiology (Reading) 2011; 157:3429-3434. [DOI: 10.1099/mic.0.053207-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Infections caused by multiresistant Gram-positive bacteria represent a major health burden in the community as well as in hospitalized patients. Enterococci, especially Enterococcus faecium, are well-known pathogens of hospitalized patients and are frequently linked with resistance against multiple antibiotics, which compromises effective therapy. Rabbit immune serum raised against heat-killed E. faecium E155, a HiRECC clone, was used in an opsonophagocytic assay, an inhibition assay and a mouse bacteraemia model to identify targets of opsonic and protective antibodies. Serum against whole heat-killed bacteria was opsonic and recognized a protein of about 72 kDa that was abundantly secreted. This protein, identified as SagA by LC-ES-MS/MS, was expressed in Escherichia coli and purified. Rabbit serum raised against the purified protein showed opsonic killing activity that was inhibited by almost 100 % using 100 µg purified protein ml−1. In a mouse bacteraemia model, a statistically significant reduction of the colony counts in blood was shown with immune rabbit serum compared with preimmune serum using the homologous and a heterologous vancomycin-resistant enterococci (VRE) strain. These results indicate that SagA could be used as a promising vaccine target to treat and/or prevent VRE bacteraemia.
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Affiliation(s)
- A. Kropec
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - I. G. Sava
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - C. Vonend
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - T. Sakinc
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - E. Grohmann
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - J. Huebner
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
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