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Wei Y, Palacios Araya D, Palmer KL. Enterococcus faecium: evolution, adaptation, pathogenesis and emerging therapeutics. Nat Rev Microbiol 2024:10.1038/s41579-024-01058-6. [PMID: 38890478 DOI: 10.1038/s41579-024-01058-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2024] [Indexed: 06/20/2024]
Abstract
The opportunistic pathogen Enterococcus faecium colonizes humans and a wide range of animals, endures numerous stresses, resists antibiotic treatment and stubbornly persists in clinical environments. The widespread application of antibiotics in hospitals and agriculture has contributed to the emergence of vancomycin-resistant E. faecium, which causes many hospital-acquired infections. In this Review, we explore recent discoveries about the evolutionary history, the environmental adaptation and the colonization and dissemination mechanisms of E. faecium and vancomycin-resistant E. faecium. These studies provide critical insights necessary for developing novel preventive and therapeutic approaches against vancomycin-resistant E. faecium and also reveal the intricate interrelationships between the environment, the microorganism and the host, providing knowledge that is broadly relevant to how antibiotic-resistant pathogens emerge and endure.
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Affiliation(s)
- Yahan Wei
- School of Podiatric Medicine, The University of Texas Rio Grande Valley, Harlingen, TX, USA
| | - Dennise Palacios Araya
- 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.
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Hourigan D, Stefanovic E, Hill C, Ross RP. Promiscuous, persistent and problematic: insights into current enterococcal genomics to guide therapeutic strategy. BMC Microbiol 2024; 24:103. [PMID: 38539119 PMCID: PMC10976773 DOI: 10.1186/s12866-024-03243-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 02/28/2024] [Indexed: 04/19/2024] Open
Abstract
Vancomycin-resistant enterococci (VRE) are major opportunistic pathogens and the causative agents of serious diseases, such as urinary tract infections and endocarditis. VRE strains mainly include species of Enterococcus faecium and E. faecalis which can colonise the gastrointestinal tract (GIT) of patients and, following growth and persistence in the gut, can transfer to blood resulting in systemic dissemination in the body. Advancements in genomics have revealed that hospital-associated VRE strains are characterised by increased numbers of mobile genetic elements, higher numbers of antibiotic resistance genes and often lack active CRISPR-Cas systems. Additionally, comparative genomics have increased our understanding of dissemination routes among patients and healthcare workers. Since the efficiency of currently available antibiotics is rapidly declining, new measures to control infection and dissemination of these persistent pathogens are urgently needed. These approaches include combinatory administration of antibiotics, strengthening colonisation resistance of the gut microbiota to reduce VRE proliferation through commensals or probiotic bacteria, or switching to non-antibiotic bacterial killers, such as bacteriophages or bacteriocins. In this review, we discuss the current knowledge of the genomics of VRE isolates and state-of-the-art therapeutic advances against VRE infections.
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Affiliation(s)
- David Hourigan
- APC Microbiome Ireland, Biosciences Institute, Biosciences Research Institute, College Rd, University College, Cork, Ireland
- School of Microbiology, University College Cork, College Rd, University College, Cork, Ireland
| | - Ewelina Stefanovic
- APC Microbiome Ireland, Biosciences Institute, Biosciences Research Institute, College Rd, University College, Cork, Ireland
- Teagasc Food Research Centre, Moorepark, Moorepark West, Fermoy, Co. Cork, Ireland
| | - Colin Hill
- APC Microbiome Ireland, Biosciences Institute, Biosciences Research Institute, College Rd, University College, Cork, Ireland
- School of Microbiology, University College Cork, College Rd, University College, Cork, Ireland
| | - R Paul Ross
- APC Microbiome Ireland, Biosciences Institute, Biosciences Research Institute, College Rd, University College, Cork, Ireland.
- School of Microbiology, University College Cork, College Rd, University College, Cork, Ireland.
- Teagasc Food Research Centre, Moorepark, Moorepark West, Fermoy, Co. Cork, Ireland.
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Roer L, Kaya H, Tedim AP, Novais C, Coque TM, Aarestrup FM, Peixe L, Hasman H, Hammerum AM, Freitas AR. VirulenceFinder for Enterococcus faecium and Enterococcus lactis: an enhanced database for detection of putative virulence markers by using whole-genome sequencing data. Microbiol Spectr 2024; 12:e0372423. [PMID: 38329344 PMCID: PMC10913372 DOI: 10.1128/spectrum.03724-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 01/20/2024] [Indexed: 02/09/2024] Open
Abstract
Enterococcus faecium (Efm) is a leading cause of hospital-associated (HA) infections, often enriched in putative virulence markers (PVMs). Recently, the Efm clade B was assigned as Enterococcus lactis (Elts), which usually lack HA-Efm infection markers. Available databases for extracting PVM are incomplete and/or present an intermix of genes from Efm and Enterococcus faecalis, with distinct virulence profiles. In this study, we constructed a new database containing 27 PVMs [acm, scm, sgrA, ecbA, fnm, sagA, hylEfm, ptsD, orf1481, fms15, fms21-fms20 (pili gene cluster 1, PGC-1), fms14-fms17-fms13 (PGC-2), empA-empB-empC (PGC-3), fms11-fms19-fms16 (PGC-4), ccpA, bepA, gls20-glsB1, and gls33-glsB] from nine reference genomes (seven Efm + two Elts). The database was validated against these reference genomes and further evaluated using a collection of well-characterized Efm (n = 43) and Elts (n = 7) control strains, by assessing PVM presence/absence and its variants together with a genomic phylogeny constructed as single-nucleotide polymorphisms. We found a high concordance between the phylogeny and in silico findings of the PVM, with Elts clustering separately and mostly carrying Elts-specific PVM gene variants. Based on our validation results, we recommend using the database with raw reads instead of assemblies to avoid missing gene variants. This newly constructed database of 27 PVMs will enable a more comprehensive characterization of Efm and Elts based on WGS data. The developed database exhibits scalability and boasts a range of applications in public health, including diagnostics, outbreak investigations, and epidemiological studies. It can be further used in risk assessment for distinguishing between safe and unsafe enterococci.IMPORTANCEThe newly constructed database, consisting of 27 putative virulence markers, is highly scalable and serves as a valuable resource for the comprehensive characterization of these closely related species using WGS data. It holds significant potential for various public health applications, including hospital outbreak investigations, surveillance, and risk assessment for probiotics and feed additives.
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Affiliation(s)
- Louise Roer
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Hülya Kaya
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Ana P. Tedim
- Group for Biomedical Research in Sepsis (BioSepsis), Instituto de Investigación Biomédica de Salamanca, Salamanca, Spain
- Grupo de Investigación Biomédica en Sepsis-BioSepsis, Hospital Universitario Río Hortega, Instituto de Investigación Biomédica de Salamanca (IBSAL), Valladollid, Spain
| | - Carla Novais
- UCIBIO, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
- Associate Laboratory i4HB, Faculty of Pharmacy, University of Porto, Institute for Health and Bioeconomy, Porto, Portugal
| | - Teresa M. Coque
- Department of Microbiology, Ramón y Cajal University Hospital and Ramón y Cajal Health Research Institute (IRYCIS), Madrid, Spain
- Network Research Centre for Infectious Diseases (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Frank M. Aarestrup
- Research Group for Genomic Epidemiology, Technical University of Denmark, National Food Institute, Lyngby, Denmark
| | - Luísa Peixe
- UCIBIO, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
- Associate Laboratory i4HB, Faculty of Pharmacy, University of Porto, Institute for Health and Bioeconomy, Porto, Portugal
| | - Henrik Hasman
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Anette M. Hammerum
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Ana R. Freitas
- UCIBIO, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
- Associate Laboratory i4HB, Faculty of Pharmacy, University of Porto, Institute for Health and Bioeconomy, Porto, Portugal
- 1H-TOXRUN—One Health Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, Gandra, Portugal
| | - On behalf of the ESCMID Study Group for Epidemiological Markers (ESGEM)
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
- Group for Biomedical Research in Sepsis (BioSepsis), Instituto de Investigación Biomédica de Salamanca, Salamanca, Spain
- Grupo de Investigación Biomédica en Sepsis-BioSepsis, Hospital Universitario Río Hortega, Instituto de Investigación Biomédica de Salamanca (IBSAL), Valladollid, Spain
- UCIBIO, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
- Associate Laboratory i4HB, Faculty of Pharmacy, University of Porto, Institute for Health and Bioeconomy, Porto, Portugal
- Department of Microbiology, Ramón y Cajal University Hospital and Ramón y Cajal Health Research Institute (IRYCIS), Madrid, Spain
- Network Research Centre for Infectious Diseases (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- Research Group for Genomic Epidemiology, Technical University of Denmark, National Food Institute, Lyngby, Denmark
- 1H-TOXRUN—One Health Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, Gandra, Portugal
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AL Rubaye M, Janice J, Bjørnholt JV, Kacelnik O, Haldorsen BC, Nygaard RM, Hegstad J, Sundsfjord A, Hegstad K. The population structure of vancomycin-resistant and -susceptible Enterococcus faecium in a low-prevalence antimicrobial resistance setting is highly influenced by circulating global hospital-associated clones. Microb Genom 2023; 9:001160. [PMID: 38112685 PMCID: PMC10763505 DOI: 10.1099/mgen.0.001160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 12/01/2023] [Indexed: 12/21/2023] Open
Abstract
Between 2010 and 2015 the incidence of vancomycin-resistant Enterococcus faecium (VREfm) in Norway increased dramatically. Hence, we selected (1) a random subset of vancomycin-resistant enterococci (VRE) from the Norwegian Surveillance System for Communicable Diseases (2010-15; n=239) and (2) Norwegian vancomycin-susceptible E. faecium (VSEfm) bacteraemia isolates from the national surveillance system for antimicrobial resistance in microbes (2008 and 2014; n=261) for further analysis. Whole-genome sequences were collected for population structure, van gene cluster, mobile genetic element and virulome analysis, as well as antimicrobial susceptibility testing. Comparative genomic and phylogeographical analyses were performed with complete genomes of global E. faecium strains from the National Center for Biotechnology Information (NCBI) (1946-2022; n=272). All Norwegian VREfm and most of the VSEfm clustered with global hospital-associated sequence types (STs) in the phylogenetic subclade A1. The vanB2 subtype carried by chromosomal Tn1549 integrative conjugative elements was the dominant van type. The major Norwegian VREfm cluster types (CTs) were in accordance with concurrent European CTs. The dominant vanB-type VREfm CTs, ST192-CT3/26 and ST117-CT24, were mostly linked to a single hospital in Norway where the clones spread after independent chromosomal acquisition of Tn1549. The less prevalent vanA VRE were associated with more diverse CTs and vanA carrying Inc18 or RepA_N plasmids with toxin-antitoxin systems. Only 5 % of the Norwegian VRE were Enterococcus faecalis, all of which contained vanB. The Norwegian VREfm and VSEfm isolates harboured CT-specific virulence factor (VF) profiles supporting biofilm formation and colonization. The dominant VREfm CTs in general hosted more virulence determinants than VSEfm. The phylogenetic clade B VSEfm isolates (n=21), recently classified as Enterococcus lactis, harboured fewer VFs than E. faecium in general, and particularly subclade A1 isolates. In conclusion, the population structure of Norwegian E. faecium isolates mirrors the globally prevalent clones and particularly concurrent European VREfm/VSEfm CTs. Novel chromosomal acquisition of vanB2 on Tn1549 from the gut microbiota, however, formed a single major hospital VREfm outbreak. Dominant VREfm CTs contained more VFs than VSEfm.
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Affiliation(s)
- Mushtaq AL Rubaye
- Research group for Host–Microbe Interactions, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Jessin Janice
- Research group for Host–Microbe Interactions, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
- Present address: Section for development, Department of Microbiology, Clinic for Laboratory Medicine, Oslo University Hospital, Oslo, Norway
| | - Jørgen Vildershøj Bjørnholt
- Department of Clinical Microbiology, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Oliver Kacelnik
- Department of Antibiotic Resistance and Infection Prevention, Norwegian Institute of Public Health, Oslo, Norway
| | - Bjørg C. Haldorsen
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Randi M. Nygaard
- Department of Microbiology, Haukeland University Hospital, Bergen, Norway
| | - Joachim Hegstad
- Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Arnfinn Sundsfjord
- Research group for Host–Microbe Interactions, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Kristin Hegstad
- Research group for Host–Microbe Interactions, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - the Norwegian VRE study group
- Research group for Host–Microbe Interactions, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
- Department of Clinical Microbiology, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Antibiotic Resistance and Infection Prevention, Norwegian Institute of Public Health, Oslo, Norway
- Department of Microbiology, Haukeland University Hospital, Bergen, Norway
- Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
- Present address: Section for development, Department of Microbiology, Clinic for Laboratory Medicine, Oslo University Hospital, Oslo, Norway
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5
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Im H, Pearson ML, Martinez E, Cichos KH, Song X, Kruckow KL, Andrews RM, Ghanem ES, Orihuela CJ. Targeting NAD+ regeneration enhances antibiotic susceptibility of Streptococcus pneumoniae during invasive disease. PLoS Biol 2023; 21:e3002020. [PMID: 36928033 PMCID: PMC10019625 DOI: 10.1371/journal.pbio.3002020] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 02/02/2023] [Indexed: 03/18/2023] Open
Abstract
Anaerobic bacteria are responsible for half of all pulmonary infections. One such pathogen is Streptococcus pneumoniae (Spn), a leading cause of community-acquired pneumonia, bacteremia/sepsis, and meningitis. Using a panel of isogenic mutants deficient in lactate, acetyl-CoA, and ethanol fermentation, as well as pharmacological inhibition, we observed that NAD(H) redox balance during fermentation was vital for Spn energy generation, capsule production, and in vivo fitness. Redox balance disruption in fermentation pathway-specific fashion substantially enhanced susceptibility to killing in antimicrobial class-specific manner. Blocking of alcohol dehydrogenase activity with 4-methylpyrazole (fomepizole), an FDA-approved drug used as an antidote for toxic alcohol ingestion, enhanced susceptibility of multidrug-resistant Spn to erythromycin and reduced bacterial burden in the lungs of mice with pneumonia and prevented the development of invasive disease. Our results indicate fermentation enzymes are de novo targets for antibiotic development and a novel strategy to combat multidrug-resistant pathogens.
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Affiliation(s)
- Hansol Im
- Department of Microbiology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Madison L. Pearson
- Department of Microbiology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Eriel Martinez
- Department of Microbiology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Kyle H. Cichos
- Department of Orthopaedic Surgery Arthroplasty Section, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Xiuhong Song
- Department of Microbiology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Katherine L. Kruckow
- Department of Microbiology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Rachel M. Andrews
- Department of Microbiology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Elie S. Ghanem
- Department of Orthopaedic Surgery Arthroplasty Section, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Carlos J. Orihuela
- Department of Microbiology, Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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Novais C, Almeida-Santos AC, Paula Pereira A, Rebelo A, Freitas AR, Peixe L. Alert for molecular data interpretation when using Enterococcus faecium reference strains reclassified as Enterococcus lactis. Gene 2023; 851:146951. [PMID: 36261083 DOI: 10.1016/j.gene.2022.146951] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/03/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Carla Novais
- UCIBIO-Applied Molecular Biosciences Unit, Laboratory of Microbiology, Department of Biological Sciences, REQUIMTE Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal.
| | - Ana C Almeida-Santos
- UCIBIO-Applied Molecular Biosciences Unit, Laboratory of Microbiology, Department of Biological Sciences, REQUIMTE Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Ana Paula Pereira
- UCIBIO-Applied Molecular Biosciences Unit, Laboratory of Microbiology, Department of Biological Sciences, REQUIMTE Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Andreia Rebelo
- UCIBIO-Applied Molecular Biosciences Unit, Laboratory of Microbiology, Department of Biological Sciences, REQUIMTE Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal; Abel Salazar Biomedical Sciences Institute (ICBAS), Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal; Technical-Scientific Area of Environmental Health, School of Health, Polytechnic Institute of Porto, Rua Dr. António Bernardino de Almeida 400, 420-072 Porto, Portugal
| | - Ana R Freitas
- UCIBIO-Applied Molecular Biosciences Unit, Laboratory of Microbiology, Department of Biological Sciences, REQUIMTE Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal; TOXRUN, Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, Rua Central da Gandra, 1317-4585 Gandra, Portugal
| | - Luísa Peixe
- UCIBIO-Applied Molecular Biosciences Unit, Laboratory of Microbiology, Department of Biological Sciences, REQUIMTE Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal
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Revtovich AV, Tjahjono E, Singh KV, Hanson BM, Murray BE, Kirienko NV. Development and Characterization of High-Throughput Caenorhabditis elegans - Enterococcus faecium Infection Model. Front Cell Infect Microbiol 2021; 11:667327. [PMID: 33996637 PMCID: PMC8116795 DOI: 10.3389/fcimb.2021.667327] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/13/2021] [Indexed: 12/16/2022] Open
Abstract
The genus Enterococcus includes two Gram-positive pathogens of particular clinical relevance: E. faecalis and E. faecium. Infections with each of these pathogens are becoming more frequent, particularly in the case of hospital-acquired infections. Like most other bacterial species of clinical importance, antimicrobial resistance (and, specifically, multi-drug resistance) is an increasing threat, with both species considered to be of particular importance by the World Health Organization and the US Centers for Disease Control. The threat of antimicrobial resistance is exacerbated by the staggering difference in the speeds of development for the discovery and development of the antimicrobials versus resistance mechanisms. In the search for alternative strategies, modulation of host-pathogen interactions in general, and virulence inhibition in particular, have drawn substantial attention. Unfortunately, these approaches require a fairly comprehensive understanding of virulence determinants. This requirement is complicated by the fact that enterococcal infection models generally require vertebrates, making them slow, expensive, and ethically problematic, particularly when considering the thousands of animals that would be needed for the early stages of experimentation. To address this problem, we developed the first high-throughput C. elegans-E. faecium infection model involving host death. Importantly, this model recapitulates many key aspects of murine peritonitis models, including utilizing similar virulence determinants. Additionally, host death is independent of peroxide production, unlike other E. faecium-C. elegans virulence models, which allows the assessment of other virulence factors. Using this system, we analyzed a panel of lab strains with deletions of targeted virulence factors. Although removal of certain virulence factors (e.g., Δfms15) was sufficient to affect virulence, multiple deletions were generally required to affect pathogenesis, suggesting that host-pathogen interactions are multifactorial. These data were corroborated by genomic analysis of selected isolates with high and low levels of virulence. We anticipate that this platform will be useful for identifying new treatments for E. faecium infection.
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Affiliation(s)
| | - Elissa Tjahjono
- Department of BioSciences, Rice University, Houston, TX, United States
| | - Kavindra V. Singh
- Division of Infectious Diseases, McGovern Medical School, University of Texas Health Science Center, Houston, TX, United States
| | - Blake M. Hanson
- Division of Infectious Diseases, McGovern Medical School, University of Texas Health Science Center, Houston, TX, United States
- Center for Infectious Diseases, School of Public Health, University of Texas Health Science Center, Houston, TX, United States
| | - Barbara E. Murray
- Division of Infectious Diseases, McGovern Medical School, University of Texas Health Science Center, Houston, TX, United States
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX, United States
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The Great ESKAPE: Exploring the Crossroads of Bile and Antibiotic Resistance in Bacterial Pathogens. Infect Immun 2020; 88:IAI.00865-19. [PMID: 32661122 DOI: 10.1128/iai.00865-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Throughout the course of infection, many pathogens encounter bactericidal conditions that threaten the viability of the bacteria and impede the establishment of infection. Bile is one of the most innately bactericidal compounds present in humans, functioning to reduce the bacterial burden in the gastrointestinal tract while also aiding in digestion. It is becoming increasingly apparent that pathogens successfully resist the bactericidal conditions of bile, including bacteria that do not normally cause gastrointestinal infections. This review highlights the ability of Enterococcus, Staphylococcus, Klebsiella, Acinetobacter, Pseudomonas, Enterobacter (ESKAPE), and other enteric pathogens to resist bile and how these interactions can impact the sensitivity of bacteria to various antimicrobial agents. Given that pathogen exposure to bile is an essential component to gastrointestinal transit that cannot be avoided, understanding how bile resistance mechanisms align with antimicrobial resistance is vital to our ability to develop new, successful therapeutics in an age of widespread and increasing antimicrobial resistance.
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Sanchez-Herrero JF, Bernabeu M, Prieto A, Hüttener M, Juárez A. Gene Duplications in the Genomes of Staphylococci and Enterococci. Front Mol Biosci 2020; 7:160. [PMID: 32850954 PMCID: PMC7396535 DOI: 10.3389/fmolb.2020.00160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 06/24/2020] [Indexed: 12/28/2022] Open
Abstract
Gene duplications are a feature of bacterial genomes. In the present work we analyze the extent of gene duplications in the genomes of three microorganisms that belong to the Firmicutes phylum and that are etiologic agents of several nosocomial infections: Staphylococcus aureus, Enterococcus faecium, and Enterococcus faecalis. In all three groups, there is an irregular distribution of duplications in the genomes of the strains analyzed. Whereas in some of the strains duplications are scarce, hundreds of duplications are present in others. In all three species, mobile DNA accounts for a large percentage of the duplicated genes: phage DNA in S. aureus, and plasmid DNA in the enterococci. Duplicates also include core genes. In all three species, a reduced group of genes is duplicated in all strains analyzed. Duplication of the deoC and rpmG genes is a hallmark of S. aureus genomes. Duplication of the gene encoding the PTS IIB subunit is detected in all enterococci genomes. In E. faecalis it is remarkable that the genomes of some strains encode duplicates of the prgB and prgU genes. They belong to the prgABCU cluster, which responds to the presence of the peptide pheromone cCF10 by expressing the surface adhesins PrgA, PrgB, and PrgC.
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Affiliation(s)
- José Francisco Sanchez-Herrero
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain.,Biodiversity Research Institute (IRBio), University of Barcelona, Barcelona, Spain.,High Content Genomics and Bioinformatics Unit, Germans Trias i Pujol Research Institute (IGTP), Campus Can Ruti, Badalona, Spain
| | - Manuel Bernabeu
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Alejandro Prieto
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Mário Hüttener
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Antonio Juárez
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain.,Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and Technology, Barcelona, Spain
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10
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Petersen I, Schlüter R, Hoff KJ, Liebscher V, Bange G, Riedel K, Pané-Farré J. Non-invasive and label-free 3D-visualization shows in vivo oligomerization of the staphylococcal alkaline shock protein 23 (Asp23). Sci Rep 2020; 10:125. [PMID: 31924851 PMCID: PMC6954212 DOI: 10.1038/s41598-019-56907-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 12/04/2019] [Indexed: 11/26/2022] Open
Abstract
Fluorescence-tags, commonly used to visualize the spatial distribution of proteins within cells, can influence the localization of the tagged proteins by affecting their stability, interaction with other proteins or the induction of oligomerization artifacts. To circumvent these obstacles, a protocol was developed to generate 50 nm thick serial sections suitable for immunogold labeling and subsequent reconstruction of the spatial distribution of immuno-labeled native proteins within individual bacterial cells. Applying this method, we show a cellular distribution of the staphylococcal alkaline shock protein 23 (Asp23), which is compatible with filament formation, a property of Asp23 that we also demonstrate in vitro.
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Affiliation(s)
- Inga Petersen
- University of Greifswald, Institute of Microbiology, Felix-Hausdorff-Str. 8, 17489, Greifswald, Germany.,Center for Functional Genomics of Microbes, Felix-Hausdorff-Str. 8, 17489, Greifswald, Germany
| | - Rabea Schlüter
- University of Greifswald, Imaging Center of the Department of Biology, Friedrich-Ludwig-Jahn-Str. 15, 17489, Greifswald, Germany
| | - Katharina J Hoff
- University of Greifswald, Institute of Mathematics and Computer Science, Walther-Rathenau-Str. 47, 17489, Greifswald, Germany.,Center for Functional Genomics of Microbes, Felix-Hausdorff-Str. 8, 17489, Greifswald, Germany
| | - Volkmar Liebscher
- University of Greifswald, Institute of Mathematics and Computer Science, Walther-Rathenau-Str. 47, 17489, Greifswald, Germany
| | - Gert Bange
- Philipps-University Marburg, SYNMIKRO Research Center and Department of Chemistry, Hans-Meerwein-Strasse 6, C07, 35043, Marburg, Germany
| | - Katharina Riedel
- University of Greifswald, Institute of Microbiology, Felix-Hausdorff-Str. 8, 17489, Greifswald, Germany.,Center for Functional Genomics of Microbes, Felix-Hausdorff-Str. 8, 17489, Greifswald, Germany
| | - Jan Pané-Farré
- University of Greifswald, Institute of Microbiology, Felix-Hausdorff-Str. 8, 17489, Greifswald, Germany. .,Center for Functional Genomics of Microbes, Felix-Hausdorff-Str. 8, 17489, Greifswald, Germany. .,Philipps-University Marburg, SYNMIKRO Research Center and Department of Chemistry, Hans-Meerwein-Strasse 6, C07, 35043, Marburg, Germany.
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11
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Adaptation to Adversity: the Intermingling of Stress Tolerance and Pathogenesis in Enterococci. Microbiol Mol Biol Rev 2019; 83:83/3/e00008-19. [PMID: 31315902 DOI: 10.1128/mmbr.00008-19] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Enterococcus is a diverse and rugged genus colonizing the gastrointestinal tract of humans and numerous hosts across the animal kingdom. Enterococci are also a leading cause of multidrug-resistant hospital-acquired infections. In each of these settings, enterococci must contend with changing biophysical landscapes and innate immune responses in order to successfully colonize and transit between hosts. Therefore, it appears that the intrinsic durability that evolved to make enterococci optimally competitive in the host gastrointestinal tract also ideally positioned them to persist in hospitals, despite disinfection protocols, and acquire new antibiotic resistances from other microbes. Here, we discuss the molecular mechanisms and regulation employed by enterococci to tolerate diverse stressors and highlight the role of stress tolerance in the biology of this medically relevant genus.
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12
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Intestinal Bile Acids Induce a Morphotype Switch in Vancomycin-Resistant Enterococcus that Facilitates Intestinal Colonization. Cell Host Microbe 2019; 25:695-705.e5. [PMID: 31031170 DOI: 10.1016/j.chom.2019.03.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 01/25/2019] [Accepted: 03/18/2019] [Indexed: 12/22/2022]
Abstract
Vancomycin-resistant Enterococcus (VRE) are highly antibiotic-resistant and readily transmissible pathogens that cause severe infections in hospitalized patients. We discovered that lithocholic acid (LCA), a secondary bile acid prevalent in the cecum and colon of mice and humans, impairs separation of growing VRE diplococci, causing the formation of long chains and increased biofilm formation. Divalent cations reversed this LCA-induced switch to chaining and biofilm formation. Experimental evolution in the presence of LCA yielded mutations in the essential two-component kinase yycG/walK and three-component response regulator liaR that locked VRE in diplococcal mode, impaired biofilm formation, and increased susceptibility to the antibiotic daptomycin. These mutant VRE strains were deficient in host colonization because of their inability to compete with intestinal microbiota. This morphotype switch presents a potential non-bactericidal therapeutic target that may help clear VRE from the intestines of dominated patients, as occurs frequently during hematopoietic stem cell transplantation.
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13
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Ferrándiz MJ, Cercenado MI, Domenech M, Tirado-Vélez JM, Escolano-Martínez MS, Yuste J, García E, de la Campa AG, Martín-Galiano AJ. An Uncharacterized Member of the Gls24 Protein Superfamily Is a Putative Sensor of Essential Amino Acid Availability in Streptococcus pneumoniae. MICROBIAL ECOLOGY 2019; 77:471-487. [PMID: 29978356 DOI: 10.1007/s00248-018-1218-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 06/03/2018] [Indexed: 06/08/2023]
Abstract
Proteins belonging to the Gls24 superfamily are involved in survival of pathogenic Gram-positive cocci under oligotrophic conditions and other types of stress, by a still unknown molecular mechanism. In Firmicutes, this superfamily includes three different valine-rich orthologal families (Gls24A, B, C) with different potential interactive partners. Whereas the Streptococcus pneumoniae Δgls24A deletion mutant experienced a general long growth delay, the Δgls24B mutant grew as the parental strain in the semisynthetic AGCH medium but failed to grow in the complex Todd-Hewitt medium. Bovine seroalbumin (BSA) was the component responsible for this phenotype. The effect of BSA on growth was concentration-dependent and was maintained when the protein was proteolyzed but not when heat-denatured, suggesting that BSA dependence was related to oligopeptide supplementation. Global transcriptional analyses of the knockout mutant revealed catabolic derepression and induction of chaperone and oligopeptide transport genes. This mutant also showed increased sensibility to cadmium and high temperature. The Δgls24B mutant behaved as a poor colonizer in the nasopharynx of mice and showed 20-fold competence impairment. Experimental data suggest that Gls24B plays a central role as a sensor of amino acid availability and its connection to sugar catabolism. This metabolic rewiring can be compensated in vitro, at the expenses of external oligopeptide supplementation, but reduce important bacteria skills prior to efficiently address systemic virulence traits. This is an example of how metabolic factors conserved in enterococci, streptococci, and staphylococci can be essential for survival in poor oligopeptide environments prior to infection progression.
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Affiliation(s)
- María J Ferrándiz
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - María I Cercenado
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Miriam Domenech
- Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - José M Tirado-Vélez
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | | | - Jose Yuste
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Ernesto García
- Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Adela G de la Campa
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
- Presidencia, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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14
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Mechanisms of Bacterial Tolerance and Persistence in the Gastrointestinal and Respiratory Environments. Clin Microbiol Rev 2018; 31:31/4/e00023-18. [PMID: 30068737 DOI: 10.1128/cmr.00023-18] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Pathogens that infect the gastrointestinal and respiratory tracts are subjected to intense pressure due to the environmental conditions of the surroundings. This pressure has led to the development of mechanisms of bacterial tolerance or persistence which enable microorganisms to survive in these locations. In this review, we analyze the general stress response (RpoS mediated), reactive oxygen species (ROS) tolerance, energy metabolism, drug efflux pumps, SOS response, quorum sensing (QS) bacterial communication, (p)ppGpp signaling, and toxin-antitoxin (TA) systems of pathogens, such as Escherichia coli, Salmonella spp., Vibrio spp., Helicobacter spp., Campylobacter jejuni, Enterococcus spp., Shigella spp., Yersinia spp., and Clostridium difficile, all of which inhabit the gastrointestinal tract. The following respiratory tract pathogens are also considered: Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Burkholderia cenocepacia, and Mycobacterium tuberculosis Knowledge of the molecular mechanisms regulating the bacterial tolerance and persistence phenotypes is essential in the fight against multiresistant pathogens, as it will enable the identification of new targets for developing innovative anti-infective treatments.
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15
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Moradigaravand D, Gouliouris T, Blane B, Naydenova P, Ludden C, Crawley C, Brown NM, Török ME, Parkhill J, Peacock SJ. Within-host evolution of Enterococcus faecium during longitudinal carriage and transition to bloodstream infection in immunocompromised patients. Genome Med 2017; 9:119. [PMID: 29282103 PMCID: PMC5744393 DOI: 10.1186/s13073-017-0507-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/07/2017] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Enterococcus faecium is a leading cause of hospital-acquired infection, particularly in the immunocompromised. Here, we use whole genome sequencing of E. faecium to study within-host evolution and the transition from gut carriage to invasive disease. METHODS We isolated and sequenced 180 E. faecium from four immunocompromised patients who developed bloodstream infection during longitudinal surveillance of E. faecium in stool and their immediate environment. RESULTS A phylogenetic tree based on single nucleotide polymorphisms (SNPs) in the core genome of the 180 isolates demonstrated several distinct clones. This was highly concordant with the population structure inferred by Bayesian methods, which contained four main BAPS (Bayesian Analysis of Population Structure) groups. The majority of isolates from each patient resided in a single group, but all four patients also carried minority populations in stool from multiple phylogenetic groups. Bloodstream isolates from each case belonged to a single BAPS group, which differed in all four patients. Analysis of 87 isolates (56 from blood) belonging to a single BAPS group that were cultured from the same patient over 54 days identified 30 SNPs in the core genome (nine intergenic, 13 non-synonymous, eight synonymous), and 250 accessory genes that were variably present. Comparison of these genetic variants in blood isolates versus those from stool or environment did not identify any variants associated with bloodstream infection. The substitution rate for these isolates was estimated to be 128 (95% confidence interval 79.82 181.77) mutations per genome per year, more than ten times higher than previous estimates for E. faecium. Within-patient variation in vancomycin resistance associated with vanA was common and could be explained by plasmid loss, or less often by transposon loss. CONCLUSIONS These findings demonstrate the diversity of E. faecium carriage by individual patients and significant within-host diversity of E. faecium, but do not provide evidence for adaptive genetic variation associated with invasion.
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Affiliation(s)
- Danesh Moradigaravand
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA, UK.
| | - Theodore Gouliouris
- Department of Medicine, University of Cambridge, Box 157, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK.
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK.
- Public Health England, Clinical Microbiology and Public Health Laboratory, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
| | - Beth Blane
- Department of Medicine, University of Cambridge, Box 157, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - Plamena Naydenova
- Department of Medicine, University of Cambridge, Box 157, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - Catherine Ludden
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Charles Crawley
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - Nicholas M Brown
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
- Public Health England, Clinical Microbiology and Public Health Laboratory, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - M Estée Török
- Department of Medicine, University of Cambridge, Box 157, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
- Public Health England, Clinical Microbiology and Public Health Laboratory, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Julian Parkhill
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA, UK
| | - Sharon J Peacock
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA, UK
- Department of Medicine, University of Cambridge, Box 157, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
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16
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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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17
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Castro R, Reguera-Brito M, López-Campos GH, Blanco MM, Aguado-Urda M, Fernández-Garayzábal JF, Gibello A. How does temperature influences the development of lactococcosis? Transcriptomic and immunoproteomic in vitro approaches. JOURNAL OF FISH DISEASES 2017; 40:1285-1297. [PMID: 28093775 DOI: 10.1111/jfd.12601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/21/2016] [Accepted: 11/22/2016] [Indexed: 06/06/2023]
Abstract
Lactococcus garvieae is the aetiological agent of lactococcosis, a haemorrhagic septicaemia that affects marine and freshwater fish, with special incidence and economic relevance in farmed rainbow trout. Water temperature is one of the most important predisposing factors in the development of lactococcosis outbreaks. Lactococcosis in trout usually occur when water temperatures rise to about 18 °C, while fish carriers remain asymptomatic at temperatures below 13 °C. The aim of this work was to analyse the differences in the complete transcriptome response of L. garvieae grown at 18 °C and at 13 °C and to identify the immunogenic proteins expressed by this bacterium at 18 °C. Our results show that water temperature influences the expression of L. garvieae genes involved in the lysis of part of the bacterial cell population and in the cold response bacterial adaptation. Moreover, the surface immunogenic protein profile at 18 °C suggests an important role of the lysozyme-like enzyme, WxL surface proteins and some putative moonlighting proteins (proteins with more than one function, usually associated with different cellular locations) as virulence factors in L. garvieae. The results of this study could provide insights into the understanding of the virulence mechanisms of L. garvieae in fish.
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Affiliation(s)
- R Castro
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
| | - M Reguera-Brito
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
| | - G H López-Campos
- Health and Biomedical Informatics Research Unit, Medical School, University of Melbourne, Melbourne, VIC, Australia
| | - M M Blanco
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
| | - M Aguado-Urda
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
| | - J F Fernández-Garayzábal
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
- Animal Health Surveillance Center (VISAVET), Complutense University, Madrid, Spain
| | - A Gibello
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
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18
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Abstract
Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the "stressome" of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.
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19
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Reguera-Brito M, Fernández-Garayzábal JF, Blanco MM, Aguado-Urda M, Gibello A. Post-stained Western blotting, a useful approach in immunoproteomic studies. J Immunol Methods 2014; 415:66-70. [PMID: 25450258 DOI: 10.1016/j.jim.2014.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 10/06/2014] [Accepted: 10/13/2014] [Indexed: 11/28/2022]
Abstract
The precise localisation of immunogenic proteins on stained two-dimensional electrophoresis (2DE) gels is occasionally difficult, contributing to the erroneous identification of unrelated non-immunogenic proteins, which is expensive and time consuming. This inconvenience can be solved by performing immunoblotting using previously stained polyacrylamide gels. This approach was proposed nearly 20 years ago but is now almost forgotten. We have evaluated the suitability of this approach to identify immunogenic proteins from Lactococcus garvieae. Some of the immunogenic proteins identified in L. garvieae, such as Gls24, have been considered important as immunotarget in different bacterial species. Post-staining western blotting facilitated the correct selection of immunogenic proteins of interest in 2D gels before their identification.
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Affiliation(s)
- Mercedes Reguera-Brito
- Department of Animal Health, Faculty of Veterinary Science, Complutense University, 28040 Madrid, Spain
| | - José F Fernández-Garayzábal
- Department of Animal Health, Faculty of Veterinary Science, Complutense University, 28040 Madrid, Spain; Animal Health Surveillance Center (VISAVET), Complutense University, 28040 Madrid, Spain
| | - M Mar Blanco
- Department of Animal Health, Faculty of Veterinary Science, Complutense University, 28040 Madrid, Spain
| | - Mónica Aguado-Urda
- Department of Animal Health, Faculty of Veterinary Science, Complutense University, 28040 Madrid, Spain
| | - Alicia Gibello
- Department of Animal Health, Faculty of Veterinary Science, Complutense University, 28040 Madrid, Spain.
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20
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Repizo GD, Espariz M, Blancato VS, Suárez CA, Esteban L, Magni C. Genomic comparative analysis of the environmental Enterococcus mundtii against enterococcal representative species. BMC Genomics 2014; 15:489. [PMID: 24942651 PMCID: PMC4076982 DOI: 10.1186/1471-2164-15-489] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 06/02/2014] [Indexed: 11/30/2022] Open
Abstract
Background Enterococcus mundtii is a yellow-pigmented microorganism rarely found in human infections. The draft genome sequence of E. mundtii was recently announced. Its genome encodes at least 2,589 genes and 57 RNAs, and 4 putative genomic islands have been detected. The objective of this study was to compare the genetic content of E. mundtii with respect to other enterococcal species and, more specifically, to identify genes coding for putative virulence traits present in enterococcal opportunistic pathogens. Results An in-depth mining of the annotated genome was performed in order to uncover the unique properties of this microorganism, which allowed us to detect a gene encoding the antimicrobial peptide mundticin among other relevant features. Moreover, in this study a comparative genomic analysis against commensal and pathogenic enterococcal species, for which genomic sequences have been released, was conducted for the first time. Furthermore, our study reveals significant similarities in gene content between this environmental isolate and the selected enterococci strains (sharing an “enterococcal gene core” of 805 CDS), which contributes to understand the persistence of this genus in different niches and also improves our knowledge about the genetics of this diverse group of microorganisms that includes environmental, commensal and opportunistic pathogens. Conclusion Although E. mundtii CRL1656 is phylogenetically closer to E. faecium, frequently responsible of nosocomial infections, this strain does not encode the most relevant relevant virulence factors found in the enterococcal clinical isolates and bioinformatic predictions indicate that it possesses the lowest number of putative pathogenic genes among the most representative enterococcal species. Accordingly, infection assays using the Galleria mellonella model confirmed its low virulence. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-489) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Christian Magni
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET) and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario S2002LRK, Argentina.
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21
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Du X, Hua X, Qu T, Jiang Y, Zhou Z, Yu Y. Molecular characterization of Rifr mutations in Enterococcus faecalis and Enterococcus faecium. J Chemother 2013; 26:217-21. [PMID: 24070269 DOI: 10.1179/1973947813y.0000000137] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mutation rate is an important factor affecting the appearance and spread of acquired antibiotic resistance. The frequencies and types of enterococci mutations were determined in this study. The MICs of rifampicin in enterococci and their rifampicin-resistant mutants were determined by the Clinical and Laboratory Standards Institute (CLSI) agar dilution method. The Enterococcus faecalis isolates A15 and 18165 showed no significant differences in mutation frequencies or mutation rates. In Enterococcus faecium, the mutation frequency and mutation rate were both 6·4-fold lower than in E. faecalis. The spectrum of mutations characterized in E. faecium B42 differed significantly from that of E. faecalis. The types and rate of mutations indicated that E. faecalis had a higher potential to develop linezolid resistance. Rifampicin resistance was associated with mutations in the rpoB gene. Rifampicin MICs for the E. faecalis mutant were 2048 mg/l, but rifampicin MICs for E. faecium mutants ranged from 64 to 1024 mg/l.
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22
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Zhang X, Bierschenk D, Top J, Anastasiou I, Bonten MJM, Willems RJL, van Schaik W. Functional genomic analysis of bile salt resistance in Enterococcus faecium. BMC Genomics 2013; 14:299. [PMID: 23641968 PMCID: PMC3653699 DOI: 10.1186/1471-2164-14-299] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 04/18/2013] [Indexed: 02/07/2023] Open
Abstract
Background Enterococcus faecium is a Gram-positive commensal bacterium of the mammalian intestinal tract. In the last two decades it has also emerged as a multi-resistant nosocomial pathogen. In order to survive in and colonize the human intestinal tract E. faecium must resist the deleterious actions of bile. The molecular mechanisms exploited by this bacterium to tolerate bile are as yet unexplored. Results In this study we used a high-throughput quantitative screening approach of transposon mutant library, termed Microarray-based Transposon Mapping (M-TraM), to identify the genetic determinants required for resistance to bile salts in E. faecium E1162. The gene gltK, which is predicted to encode a glutamate/aspartate transport system permease protein, was identified by M-TraM to be involved in bile resistance. The role of GltK in bile salt resistance was confirmed by the subsequent observation that the deletion of gltK significantly sensitized E. faecium E1162 to bile salts. To further characterize the response of E. faecium E1162 to bile salts, we performed a transcriptome analysis to identify genes that are regulated by exposure to 0.02% bile salts. Exposure to bile salts resulted in major transcriptional rearrangements, predominantly in genes involved in carbohydrate, nucleotide and coenzyme transport and metabolism. Conclusion These findings add to a better understanding of the molecular mechanisms by which E. faecium responds and resists the antimicrobial action of bile salts.
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Affiliation(s)
- Xinglin Zhang
- Department of Medical Microbiology, University Medical Center Utrecht, Heidelberglaan 100; Room G04,527, Utrecht, 3584 CX, The Netherlands.
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Massier S, Bouffartigues E, Rincé A, Maillot O, Feuilloley MGJ, Orange N, Chevalier S. Effects of a pulsed light-induced stress on Enterococcus faecalis. J Appl Microbiol 2012; 114:186-95. [PMID: 23035907 DOI: 10.1111/jam.12029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 09/16/2012] [Accepted: 09/25/2012] [Indexed: 01/28/2023]
Abstract
AIMS Pulsed light (PL) technology is a surface decontamination process that can be used on food, packaging or water. PL efficiency may be limited by its low degree of penetration or because of a shadow effect. In these cases, surviving bacteria will be able to perceive PL as a stress. Such a stress was mimicked using low transmitted energy conditions, and its effects were investigated on the highly environmental adaptable bacterium Enterococcus faecalis V583. METHODS AND RESULTS In these laboratory conditions, a complete decontamination of the artificially inoculated medium was performed using energy doses as low as 1.8 J cm(-2) , while a treatment of 0.5, 1 and 1.2 J cm(-2) led to a 2.2, 6 and 7-log(10) CFU ml(-1) reduction in the initial bacterial population, respectively. Application of a 0.5 J cm(-2) pretreatment allowed the bacteria to resist more efficiently a 1.2 J cm(-2) subsequent PL dose. This 0.5 J cm(-2) treatment increased the bacterial mutation frequency and affected the abundance of 19 proteins as revealed by a global proteome analysis. CONCLUSIONS Enterococcus faecalis is able to adapt to a PL treatment, providing a molecular response to low-energy PL dose, leading to enhanced resistance to a subsequent treatment and increasing the mutation frequency. SIGNIFICANCE AND IMPACT OF THE STUDY This study gives further insights on Ent. faecalis capacities to adapt and to resist to stress.
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Affiliation(s)
- S Massier
- LMSM, Laboratoire de Microbiologie-Signaux et Microenvironnement, EA 4312, Université de Rouen, Evreux, France
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24
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Lebreton F, van Schaik W, Sanguinetti M, Posteraro B, Torelli R, Le Bras F, Verneuil N, Zhang X, Giard JC, Dhalluin A, Willems RJL, Leclercq R, Cattoir V. AsrR is an oxidative stress sensing regulator modulating Enterococcus faecium opportunistic traits, antimicrobial resistance, and pathogenicity. PLoS Pathog 2012; 8:e1002834. [PMID: 22876178 PMCID: PMC3410868 DOI: 10.1371/journal.ppat.1002834] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 06/18/2012] [Indexed: 12/20/2022] Open
Abstract
Oxidative stress serves as an important host/environmental signal that triggers a wide range of responses in microorganisms. Here, we identified an oxidative stress sensor and response regulator in the important multidrug-resistant nosocomial pathogen Enterococcus faecium belonging to the MarR family and called AsrR (antibiotic and stress response regulator). The AsrR regulator used cysteine oxidation to sense the hydrogen peroxide which results in its dissociation to promoter DNA. Transcriptome analysis showed that the AsrR regulon was composed of 181 genes, including representing functionally diverse groups involved in pathogenesis, antibiotic and antimicrobial peptide resistance, oxidative stress, and adaptive responses. Consistent with the upregulated expression of the pbp5 gene, encoding a low-affinity penicillin-binding protein, the asrR null mutant was found to be more resistant to β-lactam antibiotics. Deletion of asrR markedly decreased the bactericidal activity of ampicillin and vancomycin, which are both commonly used to treat infections due to enterococci, and also led to over-expression of two major adhesins, acm and ecbA, which resulted in enhanced in vitro adhesion to human intestinal cells. Additional pathogenic traits were also reinforced in the asrR null mutant including greater capacity than the parental strain to form biofilm in vitro and greater persistance in Galleria mellonella colonization and mouse systemic infection models. Despite overexpression of oxidative stress-response genes, deletion of asrR was associated with a decreased oxidative stress resistance in vitro, which correlated with a reduced resistance to phagocytic killing by murine macrophages. Interestingly, both strains showed similar amounts of intracellular reactive oxygen species. Finally, we observed a mutator phenotype and enhanced DNA transfer frequencies in the asrR deleted strain. These data indicate that AsrR plays a major role in antimicrobial resistance and adaptation for survival within the host, thereby contributes importantly to the opportunistic traits of E. faecium. Multiple antibiotic-resistant isolates of the opportunistic pathogen Enterococcus faecium have emerged and spread worldwide. However, studies aimed at identifying mechanisms that underlie the transformation of E. faecium from its commensal nature into a nosocomial pathogen are scarce. We report pleiotropic roles for a novel oxidative-sensing regulator, called AsrR (antibiotic and stress response regulator), in E. faecium. Based on transcriptomic analysis, phenotypic studies, and animal models, we demonstrate that asrR deletion is responsible for i) diminished susceptibility to penicillins, vancomycin, and cationic antimicrobial peptides, ii) increased adhesion to human cells and biofilm formation, iii) a mutator phenotype and enhanced DNA transfer frequencies, iv) decreased resistance to oxidative stress both in vitro and in murine macrophages, and v) increased host-persistence in both insect and mouse models. AsrR is a stress-sensor and is promptly inactivated in the presence of hydrogen peroxide. Therefore, oxidative stress, which is a main challenge during infection, may be a significant signal used by E. faecium to promote opportunistic traits. This provides a significant resource combining, for the first time in E. faecium, a global transcriptomic approach and a thorough phenotypic study, which places AsrR as a key regulator modulating pathogenicity, antimicrobial resistance, and environmental adaptation.
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Affiliation(s)
- François Lebreton
- University of Caen Basse-Normandie, EA4655 (team “Antibioresistance”), Medical School, Caen, France
| | - Willem van Schaik
- University Medical Center Utrecht, Department of Medical Microbiology, Utrecht, The Netherlands
| | | | | | - Riccardo Torelli
- Catholic University of Sacred Heart, Institute of Microbiology, Rome, Italy
| | - Florian Le Bras
- University of Caen Basse-Normandie, EA4655 (team “Antibioresistance”), Medical School, Caen, France
| | - Nicolas Verneuil
- University of Caen Basse-Normandie, EA4655 (team “Stress and Virulence”), Caen, France
| | - Xinglin Zhang
- University Medical Center Utrecht, Department of Medical Microbiology, Utrecht, The Netherlands
| | - Jean-Christophe Giard
- University of Caen Basse-Normandie, EA4655 (team “Antibioresistance”), Medical School, Caen, France
| | - Anne Dhalluin
- University of Caen Basse-Normandie, EA4655 (team “Antibioresistance”), Medical School, Caen, France
| | - Rob J. L. Willems
- University Medical Center Utrecht, Department of Medical Microbiology, Utrecht, The Netherlands
| | - Roland Leclercq
- University of Caen Basse-Normandie, EA4655 (team “Antibioresistance”), Medical School, Caen, France
- University Hospital of Caen, Department of Microbiology, Caen, France
| | - Vincent Cattoir
- University of Caen Basse-Normandie, EA4655 (team “Antibioresistance”), Medical School, Caen, France
- University Hospital of Caen, Department of Microbiology, Caen, France
- * E-mail:
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25
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Gaca AO, Abranches J, Kajfasz JK, Lemos JA. Global transcriptional analysis of the stringent response in Enterococcus faecalis. MICROBIOLOGY-SGM 2012; 158:1994-2004. [PMID: 22653948 DOI: 10.1099/mic.0.060236-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In Enterococcus faecalis, production of guanosine tetraphosphate/guanosine pentaphosphate [(p)ppGpp], the effector molecule of the stringent response, is controlled by the bifunctional synthetase/hydrolase RelA and the monofunctional synthetase RelQ. Previously, the (p)ppGpp profiles of strains lacking relA, relQ or both genes indicated that RelA is the primary enzyme responsible for (p)ppGpp synthesis under stress conditions, while the contributions of RelQ to the stringent response and cell homeostasis remained elusive. Here, survival within the mouse-derived macrophage cell line J774A.1 and killing of Galleria mellonella supported initial evidence that virulence was attenuated in the (p)ppGpp(0) ΔrelAΔrelQ strain but not in the ΔrelA or ΔrelQ strains. We performed, for the first time to our knowledge, global transcriptome analysis in a documented (p)ppGpp(0) Gram-positive bacterium and provided the first insights into the role of a Gram-positive monofunctional (p)ppGpp synthetase in transcriptional regulation. Transcription profiling after mupirocin treatment confirmed that RelA is the major enzyme responsible for the (p)ppGpp-mediated transcriptional repression of genes associated with macromolecular biosynthesis, but also revealed that RelQ is required for full and timely stringent response induction. The delayed transcriptional response of ΔrelQ could not be correlated with reduced or slower production of (p)ppGpp, in part because RelA-dependent (p)ppGpp accumulation occurred very rapidly. Comparisons of the transcriptional responses of ΔrelA or ΔrelAΔrelQ strains with the parent strain under starvation conditions revealed upregulation of operons involved in energy metabolism in the (p)ppGpp(0) strain. Thus, while ΔrelA and ΔrelAΔrelQ cannot use (p)ppGpp to sense and respond to stresses, fitness of ΔrelAΔrelQ may be further impaired due to an unbalanced metabolism.
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Affiliation(s)
- Anthony O Gaca
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Jacqueline Abranches
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Jessica K Kajfasz
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - José A Lemos
- Center for Oral Biology and Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
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26
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Weisser M, Oostdijk EA, Willems RJL, Bonten MJM, Frei R, Elzi L, Halter J, Widmer AF, Top J. Dynamics of ampicillin-resistant Enterococcus faecium clones colonizing hospitalized patients: data from a prospective observational study. BMC Infect Dis 2012; 12:68. [PMID: 22436212 PMCID: PMC3359220 DOI: 10.1186/1471-2334-12-68] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 03/22/2012] [Indexed: 11/18/2022] Open
Abstract
Background Little is known about the dynamics of colonizing Enterococcus faecium clones during hospitalization, invasive infection and after discharge. Methods In a prospective observational study we compared intestinal E. faecium colonization in three patient cohorts: 1) Patients from the Hematology Unit at the University Hospital Basel (UHBS), Switzerland, were investigated by weekly rectal swabs (RS) during hospitalization (group 1a, n = 33) and monthly after discharge (group 1b, n = 21). 2) Patients from the Intensive Care Unit (ICU) at the University Medical Center Utrecht, the Netherlands (group 2, n = 25) were swabbed weekly. 3) Patients with invasive E. faecium infection at UHBS were swabbed at the time of infection (group 3, n = 22). From each RS five colonies with typical E. faecium morphology were picked. Species identification was confirmed by PCR and ampicillin-resistant E. faecium (ARE) isolates were typed using Multiple Locus Variable Number Tandem Repeat Analysis (MLVA). The Simpson's Index of Diversity (SID) was calculated. Results Out of 558 ARE isolates from 354 RS, MT159 was the most prevalent clone (54%, 100%, 52% and 83% of ARE in groups 1a, 1b, 2 and 3, respectively). Among hematological inpatients 13 (40%) had ARE. During hospitalization, the SID of MLVA-typed ARE decreased from 0.745 [95%CI 0.657-0.833] in week 1 to 0.513 [95%CI 0.388-0.637] in week 3. After discharge the only detected ARE was MT159 in 3 patients. In the ICU (group 2) almost all patients (84%) were colonized with ARE. The SID increased significantly from 0.373 [95%CI 0.175-0.572] at week 1 to a maximum of 0.808 [95%CI 0.768-0.849] at week 3 due to acquisition of multiple ARE clones. All 16 patients with invasive ARE were colonized with the same MLVA clone (p < 0.001). Conclusions In hospitalized high-risk patients MT159 is the most frequent colonizer and cause of invasive E. faecium infections. During hospitalization, ASE are quickly replaced by ARE. Diversity of ARE increases on units with possible cross-transmission such as ICUs. After hospitalization ARE are lost with the exception of MT159. In invasive infections, the invasive clone is the predominant gut colonizer.
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Affiliation(s)
- Maja Weisser
- Division of Infectious Diseases & Hospital Epidemiology, University Hospital Basel, Basel, Switzerland.
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27
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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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28
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Santagati M, Campanile F, Stefani S. Genomic diversification of enterococci in hosts: the role of the mobilome. Front Microbiol 2012; 3:95. [PMID: 22435066 PMCID: PMC3303144 DOI: 10.3389/fmicb.2012.00095] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 02/27/2012] [Indexed: 12/11/2022] Open
Abstract
Enterococci are ubiquitous lactic acid bacteria, possessing a flexible nature that allows them to colonize various environments and hosts but also to be opportunistic pathogens. Many papers have contributed to a better understanding of: (i) the taxonomy of this complex group of microorganisms; (ii) intra-species variability; (iii) the role of different pathogenicity traits; and (iv) some markers related to the character of host-specificity, but the reasons of such incredible success of adaptability is still far from being fully explained. Recently, genomic-based studies have improved our understanding of the genome diversity of the most studied species, i.e., E. faecalis and E. faecium. From these studies, what is becoming evident is the role of the mobilome in adding new abilities to colonize new hosts and environments, and eventually in driving their evolution: specific clones associated with human infections or specific hosts can exist, but probably the consideration of these populations as strictly clonal groups is only partially correct. The variable presence of mobile genetic elements may, indeed, be one of the factors involved in the evolution of one specific group in a specific host and/or environment. Certainly more extensive studies using new high throughput technologies are mandatory to fully understand the evolution of predominant clones and species in different hosts and environments.
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Affiliation(s)
- Maria Santagati
- Molecular Microbiology and Antibiotic Resistance Lab, Department of Microbiology, University of Catania Catania, Italy
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29
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Analysis of PBP5 of early U.S. isolates of Enterococcus faecium: sequence variation alone does not explain increasing ampicillin resistance over time. Antimicrob Agents Chemother 2011; 55:3272-7. [PMID: 21576454 DOI: 10.1128/aac.00099-11] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent studies have shown that ampicillin resistance has increased steadily over the past 3 decades within U.S. Enterococcus faecium isolates. Analysis of the predicted PBP5 protein of 41 isolates showed a consensus PBP5 pattern for the 9 isolates with MICs of <4 μg/ml that is distinctly different from the PBP5 consensus of the 32 isolates with MICs of >4 μg/ml with ∼5% difference between these; however, there were no consistent amino acid changes that correlated with specific increases in the MICs of ampicillin within the latter group. Analysis of three other genes encoding cell wall/surface proteins also showed that there are two distinct evolutionary groups for each gene, but with occasional mixing of genes, consistent with a species that evolves by recombination.
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30
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Relative contributions of Ebp Pili and the collagen adhesin ace to host extracellular matrix protein adherence and experimental urinary tract infection by Enterococcus faecalis OG1RF. Infect Immun 2011; 79:2901-10. [PMID: 21505082 DOI: 10.1128/iai.00038-11] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies have demonstrated that the ebp operon and the ace gene of Enterococcus faecalis, encoding endocarditis- and biofilm-associated pili and an adhesin to collagen of E. faecalis, respectively, are both important in experimental urinary tract infections (UTI) and endocarditis. We have also shown that growth of E. faecalis in brain heart infusion (BHI) serum enhances Ebp pilus and Ace production and increases adherence to several host extracellular matrix proteins. Here, we report that deletion of ebpABC almost eliminated serum-elicited adherence to fibrinogen (P < 0.0001), resulted in moderate reduction in adherence to collagen (P < 0.05), and had no effect on fibronectin adherence relative to that of wild-type OG1RF. An OG1RFΔaceΔebpABC double mutant showed further reduced collagen adherence versus that of the OG1RFΔace or OG1RFΔebpABC mutants (P < 0.001). These results were corroborated by complementation and/or studies with native pilus-enriched surface extracts and a collagen-secreting 3T6 fibroblast cell line, as well as antibody inhibition. In the UTI model, both the OG1RFΔace and OG1RFΔaceΔebpABC mutants were found to be significantly attenuated compared to the wild type; however, no significant differences were observed between individual ace or ebp mutants and the OG1RFΔaceΔebpABC mutant. In summary, these data implicate the Ebp pili as having some role in collagen adherence, albeit less than that of Ace, and a very major role in fibrinogen adherence, which may explain in part the importance of these pili in experimental endocarditis. The OG1RFΔaceΔebpABC mutant was attenuated in the UTI model, although not significantly more so than the Δace or ΔebpABC mutants, suggesting involvement of other E. faecalis factors in urinary tract colonization or infection.
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