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Zaidi SEZ, Zaheer R, Zovoilis A, McAllister TA. Enterococci as a One Health indicator of antimicrobial resistance. Can J Microbiol 2024; 70:303-335. [PMID: 38696839 DOI: 10.1139/cjm-2024-0024] [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: 05/04/2024]
Abstract
The rapid increase of antimicrobial-resistant bacteria in humans and livestock is concerning. Antimicrobials are essential for the treatment of disease in modern day medicine, and their misuse in humans and food animals has contributed to an increase in the prevalence of antimicrobial-resistant bacteria. Globally, antimicrobial resistance is recognized as a One Health problem affecting humans, animals, and environment. Enterococcal species are Gram-positive bacteria that are widely distributed in nature. Their occurrence, prevalence, and persistence across the One Health continuum make them an ideal candidate to study antimicrobial resistance from a One Health perspective. The objective of this review was to summarize the role of enterococci as an indicator of antimicrobial resistance across One Health sectors. We also briefly address the prevalence of enterococci in human, animal, and environmental settings. In addition, a 16S RNA gene-based phylogenetic tree was constructed to visualize the evolutionary relationship among enterococcal species and whether they segregate based on host environment. We also review the genomic basis of antimicrobial resistance in enterococcal species across the One Health continuum.
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Affiliation(s)
- Sani-E-Zehra Zaidi
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1, Canada
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
- University of Manitoba, Department of Biochemistry and Medical Genetics, 745 Bannatyne Ave, Winnipeg
| | - Rahat Zaheer
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1, Canada
| | - Athanasios Zovoilis
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
- University of Manitoba, Department of Biochemistry and Medical Genetics, 745 Bannatyne Ave, Winnipeg
| | - Tim A McAllister
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1, Canada
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Otunba AA, Osuntoki AA, Olukoya DK, Babalola BA. Genomic, biochemical and microbial evaluation of probiotic potentials of bacterial isolates from fermented sorghum products. Heliyon 2021; 7:e08536. [PMID: 34926862 PMCID: PMC8646963 DOI: 10.1016/j.heliyon.2021.e08536] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/11/2021] [Accepted: 11/29/2021] [Indexed: 12/24/2022] Open
Abstract
Fermented products, including Ogi-baba and Pito, provide several health benefits, particularly when probiotics are used in the fermentation process. Probiotic microorganisms exert strain-specific health-promoting activities on humans and animals. The objective of this study was to investigate the probiotic potentials of Lactic-acid bacteria (LAB) isolates from indigenous fermented sorghum products (Ogi-baba and Pito). The LAB isolates were screened for potential probiotic properties by antagonistic activity against eight enteropathogenic clinical bacteria isolates (Escherichia coli, Klebsiella sp., Helicobacter pylori, Bacillus sp., Staphylococcus sp., Salmonella sp., Pseudomonas sp. and Listeria monocytogenes) as indicator organisms using the agar well diffusion technique. The organisms were also screened for acidity, bile tolerance, antibiotic susceptibility, production of lactic acid, diacetyl and hydrogen peroxide. β-galactosidase assay was also done. Genomic DNA was extracted from the two selected LAB isolates; the 16S rRNA were amplified and sequenced. The sequence data were subjected to Basic Local Alignment Search Tool (BLAST) and molecular phylogenetic analyses to identify the isolates. The isolates were identified as strains of Lactobacillus plantarum and Pediococcus pentosaceus. The sequence data for these two isolates were submitted to the Genbank with accession numbers KP883298 and KP883297 respectively. The P. pentosaceus strain (PB2) strain exhibited β-galactosidase activity as well as L. plantrum strain (OB6). The study revealed exceptional probiotic potentials of two LAB namely Lactobacillus plantarum strain (OB6) and Pediococcus pentosaceus strain (PB2) isolated from fermented sorghum products, Ogi-baba and Pito respectively. Hence, the two LAB strains may be potentially used as probiotic to prevent some enteropathogen-induced gastrointestinal disorders; reduce the incidence of respiratory tract infections and for the management of lactose in intolerance.
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Affiliation(s)
| | | | | | - Benjamin Ayodipupo Babalola
- Department of Biological Sciences, College of Basic and Applied Sciences, Mountain Top University, Ogun, Nigeria
- Corresponding author.
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Guffey AA, Loll PJ. Regulation of Resistance in Vancomycin-Resistant Enterococci: The VanRS Two-Component System. Microorganisms 2021; 9:2026. [PMID: 34683347 PMCID: PMC8541618 DOI: 10.3390/microorganisms9102026] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 01/20/2023] Open
Abstract
Vancomycin-resistant enterococci (VRE) are a serious threat to human health, with few treatment options being available. New therapeutics are urgently needed to relieve the health and economic burdens presented by VRE. A potential target for new therapeutics is the VanRS two-component system, which regulates the expression of vancomycin resistance in VRE. VanS is a sensor histidine kinase that detects vancomycin and in turn activates VanR; VanR is a response regulator that, when activated, directs expression of vancomycin-resistance genes. This review of VanRS examines how the expression of vancomycin resistance is regulated, and provides an update on one of the field's most pressing questions: How does VanS sense vancomycin?
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Affiliation(s)
| | - Patrick J. Loll
- Department of Biochemistry & Molecular Biology, College of Medicine, Drexel University, Philadelphia, PA 19102, USA;
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4
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Lytic bacteriophages facilitate antibiotic sensitization of Enterococcus faecium. Antimicrob Agents Chemother 2021; 65:AAC.00143-21. [PMID: 33649110 PMCID: PMC8092871 DOI: 10.1128/aac.00143-21] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Enterococcus faecium, a commensal of the human intestine, has emerged as a hospital-adapted, multi-drug resistant (MDR) pathogen. Bacteriophages (phages), natural predators of bacteria, have regained attention as therapeutics to stem the rise of MDR bacteria. Despite their potential to curtail MDR E. faecium infections, the molecular events governing E. faecium-phage interactions remain largely unknown. Such interactions are important to delineate because phage selective pressure imposed on E. faecium will undoubtedly result in phage resistance phenotypes that could threaten the efficacy of phage therapy. In an effort to understand the emergence of phage resistance in E. faecium, three newly isolated lytic phages were used to demonstrate that E. faecium phage resistance is conferred through an array of cell wall-associated molecules, including secreted antigen A (SagA), enterococcal polysaccharide antigen (Epa), wall teichoic acids, capsule, and an arginine-aspartate-aspartate (RDD) protein of unknown function. We find that capsule and Epa are important for robust phage adsorption and that phage resistance mutations in sagA, epaR, and epaX enhance E. faecium susceptibility to ceftriaxone, an antibiotic normally ineffective due to its low affinity for enterococcal penicillin binding proteins. Consistent with these findings, we provide evidence that phages potently synergize with cell wall (ceftriaxone and ampicillin) and membrane-acting (daptomycin) antimicrobials to slow or completely inhibit the growth of E. faecium Our work demonstrates that the evolution of phage resistance comes with fitness defects resulting in drug sensitization and that lytic phages could serve as effective antimicrobials for the treatment of E. faecium infections.
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Riccardi N, Monticelli J, Antonello RM, Di Lallo G, Frezza D, Luzzati R, Di Bella S. Therapeutic Options for Infections due to vanB Genotype Vancomycin-Resistant Enterococci. Microb Drug Resist 2020; 27:536-545. [PMID: 32799629 DOI: 10.1089/mdr.2020.0171] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Enterococci are ubiquitous, facultative, anaerobic Gram-positive bacteria that mainly reside, as part of the normal microbiota, in the gastrointestinal tracts of several animal species, including humans. These bacteria have the capability to turn from a normal gut commensal organism to an invasive pathogen in patients debilitated by prolonged hospitalization, concurrent illnesses, and/or exposed to broad-spectrum antibiotics. The majority of vancomycin-resistant enterococcus (VRE) infections are linked to the vanA genotype; however, outbreaks caused by vanB-type VREs have been increasingly reported, representing a new challenge for effective antimicrobial treatment. Teicoplanin, daptomycin, fosfomycin, and linezolid are useful antimicrobials for infections due to vanB enterococci. In addition, new drugs have been developed (e.g., dalbavancin, telavancin, and tedizolid), new molecules will soon be available (e.g., eravacycline, omadacycline, and oritavancin), and new treatment strategies are progressively being used in clinical practice (e.g., combination therapies and bacteriophages). The aim of this article is to discuss the pathogenesis of infections due to enterococci harboring the vanB operon (vanBVRE) and their therapeutic, state-of-the-art, and future treatment options and provide a comprehensive and easy to use review for clinical purposes.
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Affiliation(s)
- Niccolò Riccardi
- Department of Infectious-Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | - Jacopo Monticelli
- Hospital Direction, AULSS6 Euganea Ospedali Riuniti Padova Sud, Monselice, Italy
| | | | - Gustavo Di Lallo
- Department of Biology, University of Rome "Tor Vergata," Rome, Italy
| | - Domenico Frezza
- Department of Biology, University of Rome "Tor Vergata," Rome, Italy
| | - Roberto Luzzati
- Infectious Diseases Department, Azienda Sanitaria Universitaria Integrata di Trieste, Trieste, Italy
| | - Stefano Di Bella
- Infectious Diseases Department, Azienda Sanitaria Universitaria Integrata di Trieste, Trieste, Italy
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6
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A critical review of antibiotic resistance in probiotic bacteria. Food Res Int 2020; 136:109571. [PMID: 32846610 DOI: 10.1016/j.foodres.2020.109571] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/16/2020] [Accepted: 07/17/2020] [Indexed: 12/12/2022]
Abstract
Probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit upon the host. At present, probiotics are gaining popularity worldwide and are widely used in food and medicine. Consumption of probiotics is increasing with further in-depth research on the relationship between intestinal flora and host health. Most people pay more attention to the function of probiotics but ignore their potential risks, such as infection and antibiotic resistance transfer to pathogenic microbes. Physiological functions, effects and mechanisms of action of probiotics were covered in this review, as well as the antibiotic resistance phenotypes, mechanisms and genes found in probiotics. Typical cases of antibiotic resistance of probiotics were also highlighted, as well as the potential risks (including pathogenicity, infectivity and excessive immune response) and corresponding strategies (dosage, formulation, and administration route). This timely study provides an avenue for further research, development and application of probiotics.
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Lee T, Pang S, Stegger M, Sahibzada S, Abraham S, Daley D, Coombs G. A three-year whole genome sequencing perspective of Enterococcus faecium sepsis in Australia. PLoS One 2020; 15:e0228781. [PMID: 32059020 PMCID: PMC7021281 DOI: 10.1371/journal.pone.0228781] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 01/23/2020] [Indexed: 12/02/2022] Open
Abstract
Background Over the last three decades, hospital adapted clonal complex (CC) 17 strains of Enterococcus faecium have acquired and exchanged antimicrobial resistance genes leading to the widespread resistance to clinically important antimicrobials globally. In Australia, a high prevalence of vancomycin resistance has been reported in E. faecium in the last decade. Methods In this study, we determined the phylogenetic relationship and genetic characteristics of E. faecium collected from hospitalized patients with blood stream infections throughout Australia from 2015 to 2017 using high throughput molecular techniques. Results Using single nucleotide polymorphism based phylogenetic inference, three distinct clusters of isolates were observed with additional sub-clustering. One cluster harboured mostly non-CC17 isolates while two clusters were dominant for the vanA and vanB operons. Conclusion The gradual increase in dominance of the respective van operon was observed in both the vanA and vanB dominant clusters suggesting a strain-van operon affinity. The high prevalence of the van operon within isolates of a particular sub-cluster was linked to an increased number of isolates and 30-day all-cause mortality. Different dominant sub-clusters were observed in each region of Australia. Findings from this study can be used to put future surveillance data into a broader perspective including the detection of novel E. faecium strains in Australia as well as the dissemination and evolution of each strain.
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Affiliation(s)
- Terence Lee
- Antimicrobial Resistance and Infectious Diseases Research Laboratory, Murdoch University, Murdoch, Australia
| | - Stanley Pang
- Antimicrobial Resistance and Infectious Diseases Research Laboratory, Murdoch University, Murdoch, Australia
| | - Marc Stegger
- Antimicrobial Resistance and Infectious Diseases Research Laboratory, Murdoch University, Murdoch, Australia
- Statens Serum Institute, Copenhagen, Denmark
| | - Shafi Sahibzada
- Antimicrobial Resistance and Infectious Diseases Research Laboratory, Murdoch University, Murdoch, Australia
| | - Sam Abraham
- Antimicrobial Resistance and Infectious Diseases Research Laboratory, Murdoch University, Murdoch, Australia
| | - Denise Daley
- Australian Group on Antimicrobial Resistance (AGAR), Fiona Stanley Hospital, Murdoch, Australia
| | - Geoffrey Coombs
- Antimicrobial Resistance and Infectious Diseases Research Laboratory, Murdoch University, Murdoch, Australia
- Statens Serum Institute, Copenhagen, Denmark
- * E-mail:
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Gao W, Howden BP, Stinear TP. Evolution of virulence in Enterococcus faecium, a hospital-adapted opportunistic pathogen. Curr Opin Microbiol 2017; 41:76-82. [PMID: 29227922 DOI: 10.1016/j.mib.2017.11.030] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 11/28/2017] [Accepted: 11/30/2017] [Indexed: 12/29/2022]
Abstract
Enterococci are long-standing members of the human microbiome and they are also widely distributed in nature. However, with the surge of antibiotic-resistance in recent decades, two enterococcal species (Enterococcus faecalis and Enterococcus faecium) have emerged to become significant nosocomial pathogens, acquiring extensive antibiotic resistance. In this review, we summarize what is known about the evolution of virulence in E. faecium, highlighting a specific clone of E. faecium called ST796 that has emerged recently and spread globally.
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Affiliation(s)
- Wei Gao
- Department of Microbiology and Immunology, The Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia
| | - Benjamin P Howden
- Department of Microbiology and Immunology, The Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia; Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia; Infectious Diseases Department, Austin Health, Heidelberg, Victoria 3084, Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, The Doherty Institute for Infection and Immunity, University of Melbourne, Victoria 3010, Australia.
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Homologous Recombination within Large Chromosomal Regions Facilitates Acquisition of β-Lactam and Vancomycin Resistance in Enterococcus faecium. Antimicrob Agents Chemother 2016; 60:5777-86. [PMID: 27431230 PMCID: PMC5038250 DOI: 10.1128/aac.00488-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 07/06/2016] [Indexed: 02/06/2023] Open
Abstract
The transfer of DNA between Enterococcus faecium strains has been characterized both by the movement of well-defined genetic elements and by the large-scale transfer of genomic DNA fragments. In this work, we report on the whole-genome analysis of transconjugants resulting from mating events between the vancomycin-resistant E. faecium C68 strain and the vancomycin-susceptible D344RRF strain to discern the mechanism by which the transferred regions enter the recipient chromosome. Vancomycin-resistant transconjugants from five independent matings were analyzed by whole-genome sequencing. In all cases but one, the penicillin binding protein 5 (pbp5) gene and the Tn5382 vancomycin resistance transposon were transferred together and replaced the corresponding pbp5 region of D344RRF. In one instance, Tn5382 inserted independently downstream of the D344RRF pbp5 gene. Single nucleotide variant (SNV) analysis suggested that entry of donor DNA into the recipient chromosome occurred by recombination across regions of homology between donor and recipient chromosomes, rather than through insertion sequence-mediated transposition. The transfer of genomic DNA was also associated with the transfer of C68 plasmid pLRM23 and another putative plasmid. Our data are consistent with the initiation of transfer by cointegration of a transferable plasmid with the donor chromosome, with subsequent circularization of the plasmid-chromosome cointegrant in the donor prior to transfer. Entry into the recipient chromosome most commonly occurred across regions of homology between donor and recipient chromosomes.
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Hansen TA, Joshi T, Larsen AR, Andersen PS, Harms K, Mollerup S, Willerslev E, Fuursted K, Nielsen LP, Hansen AJ. Vancomycin gene selection in the microbiome of urban Rattus norvegicus from hospital environment. EVOLUTION MEDICINE AND PUBLIC HEALTH 2016; 2016:219-26. [PMID: 27412864 PMCID: PMC4972940 DOI: 10.1093/emph/eow021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 06/29/2016] [Indexed: 01/09/2023]
Abstract
Background and objectives: Widespread use of antibiotics has resulted in selection pressure on genes that make bacteria non-responsive to antibiotics. These antibiotic-resistant bacteria are currently a major threat to global health. There are various possibilities for the transfer of antibiotic resistance genes. It has been argued that animal vectors such as Rattus norvegicus (R. norvegicus) living in hospital sewage systems are ideal for carrying pathogens responsible for fatal diseases in humans. Methodology: Using a metagenomic sequencing approach, we investigated faecal samples of R. norvegicus from three major cities for the presence of antibiotic resistance genes. Results: We show that despite the shared resistome within samples from the same geographic locations, samples from hospital area carry significantly abundant vancomycin resistance genes. Conclusions and implications: The observed pattern is consistent with a selection for vancomycin genes in the R. norvegicus microbiome, potentially driven by the outflow of antibiotics and antibiotic-resistant bacteria into the wastewater systems. Carriage of vancomycin resistance may suggest that R. norvegicus is acting as a reservoir for possible transmission to the human population.
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Affiliation(s)
- Thomas Arn Hansen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, DK-1350, Denmark
| | - Tejal Joshi
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Kemitorvet, 2800, Kgs, Lyngby, Denmark
| | | | | | - Klaus Harms
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, DK-1350, Denmark
| | - Sarah Mollerup
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, DK-1350, Denmark
| | - Eske Willerslev
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, DK-1350, Denmark
| | - Kurt Fuursted
- Department of Microbiology & Infection Control, Statens Serum Institut
| | - Lars Peter Nielsen
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, Copenhagen S, DK-2300, Denmark
| | - Anders Johannes Hansen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, DK-1350, Denmark;
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Hasan B, Järhult JD. Absence of vancomycin-resistant enterococci among highly ESBL-positive crows (Corvus splendens) foraging on hospital waste in Bangladesh. Infect Ecol Epidemiol 2015; 5:29761. [PMID: 26679560 PMCID: PMC4683987 DOI: 10.3402/iee.v5.29761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/10/2015] [Accepted: 11/09/2015] [Indexed: 11/15/2022] Open
Abstract
Background Vancomycin-resistant enterococci (VRE) have emerged as a growing problem in hospitals; however, domesticated animals, poultry, and wild birds are acting as potential reservoirs. There is a knowledge gap in the Epidemiology of VRE from Bangladesh. Methods To study the prevalence of VRE and the mechanisms of resistance implicated among wild birds, 238 fecal samples were collected in 2010 from house crows (Corvus splendens) foraging on hospital waste in Bangladesh. Fecal samples were screened by analyzing color change in broth and screening for vanA and vanB resistant genes by PCR. Results Neither vanA nor vanB genes were detected from the fecal samples. The house crow does not seem to constitute a reservoir for VRE. Conclusion The zero prevalence is an indication that foraging on hospital waste does not constitute a major risk of VRE carriage in house crows and this is the first study to focus on the prevalence of VRE from wild birds in Bangladesh.
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Affiliation(s)
- Badrul Hasan
- Section of Infectious Diseases, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.,Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Biomedical Centre (BMC), Uppsala University, Uppsala, Sweden; ;
| | - Josef D Järhult
- Section of Infectious Diseases, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.,Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Biomedical Centre (BMC), Uppsala University, Uppsala, Sweden
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Mikalsen T, Pedersen T, Willems R, Coque TM, Werner G, Sadowy E, van Schaik W, Jensen LB, Sundsfjord A, Hegstad K. Investigating the mobilome in clinically important lineages of Enterococcus faecium and Enterococcus faecalis. BMC Genomics 2015; 16:282. [PMID: 25885771 PMCID: PMC4438569 DOI: 10.1186/s12864-015-1407-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 02/27/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The success of Enterococcus faecium and E. faecalis evolving as multi-resistant nosocomial pathogens is associated with their ability to acquire and share adaptive traits, including antimicrobial resistance genes encoded by mobile genetic elements (MGEs). Here, we investigate this mobilome in successful hospital associated genetic lineages, E. faecium sequence type (ST)17 (n=10) and ST78 (n=10), E. faecalis ST6 (n=10) and ST40 (n=10) by DNA microarray analyses. RESULTS The hybridization patterns of 272 representative targets including plasmid backbones (n=85), transposable elements (n=85), resistance determinants (n=67), prophages (n=29) and clustered regularly interspaced short palindromic repeats (CRISPR)-cas sequences (n=6) separated the strains according to species, and for E. faecalis also according to STs. RCR-, Rep_3-, RepA_N- and Inc18-family plasmids were highly prevalent and with the exception of Rep_3, evenly distributed between the species. There was a considerable difference in the replicon profile, with rep 17/pRUM , rep 2/pRE25 , rep 14/EFNP1 and rep 20/pLG1 dominating in E. faecium and rep 9/pCF10 , rep 2/pRE25 and rep 7 in E. faecalis strains. We observed an overall high correlation between the presence and absence of genes coding for resistance towards antibiotics, metals, biocides and their corresponding MGEs as well as their phenotypic antimicrobial susceptibility pattern. Although most IS families were represented in both E. faecalis and E. faecium, specific IS elements within these families were distributed in only one species. The prevalence of IS256-, IS3-, ISL3-, IS200/IS605-, IS110-, IS982- and IS4-transposases was significantly higher in E. faecium than E. faecalis, and that of IS110-, IS982- and IS1182-transposases in E. faecalis ST6 compared to ST40. Notably, the transposases of IS981, ISEfm1 and IS1678 that have only been reported in few enterococcal isolates were well represented in the E. faecium strains. E. faecalis ST40 strains harboured possible functional CRISPR-Cas systems, and still resistance and prophage sequences were generally well represented. CONCLUSIONS The targeted MGEs were highly prevalent among the selected STs, underlining their potential importance in the evolution of hospital-adapted lineages of enterococci. Although the propensity of inter-species horizontal gene transfer (HGT) must be emphasized, the considerable species-specificity of these MGEs indicates a separate vertical evolution of MGEs within each species, and for E. faecalis within each ST.
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Affiliation(s)
- Theresa Mikalsen
- Research group for Host-microbe Interactions, Department of Medical Biology, Faculty of Health Science, UiT - The Arctic University of Norway, Tromsø, Norway.
| | - Torunn Pedersen
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway.
| | - Rob Willems
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Teresa M Coque
- Servicio de Microbiologia, Hospital Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain. .,Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBER-ESP), Madrid, Spain.
| | - Guido Werner
- Division of Nosocomial Pathogens and Antibiotic Resistance, Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany.
| | - Ewa Sadowy
- Department of Molecular Microbiology, National Medicines Institute, ul, Chełmska 30/34, 00-725, Warsaw, Poland.
| | - Willem van Schaik
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Lars Bogø Jensen
- Division of Food Microbiologyt, National Food Institute, Danish Technical University, Copenhagen V, Denmark.
| | - Arnfinn Sundsfjord
- Research group for Host-microbe Interactions, Department of Medical Biology, Faculty of Health Science, 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, Faculty of Health Science, 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.
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13
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Hendrickx APA, van Schaik W, Willems RJL. The cell wall architecture of Enterococcus faecium: from resistance to pathogenesis. Future Microbiol 2014; 8:993-1010. [PMID: 23902146 DOI: 10.2217/fmb.13.66] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The cell wall of Gram-positive bacteria functions as a surface organelle that continuously interacts with its environment through a plethora of cell wall-associated molecules. Enterococcus faecium is a normal inhabitant of the GI tract of mammals, but has recently become an important etiological agent of hospital-acquired infections in debilitated patients. Insights into the assembly and function of enterococcal cell wall components and their interactions with the host during colonization and infection are essential to explain the worldwide emergence of E. faecium as an important multiantibiotic-resistant nosocomial pathogen. Understanding the biochemistry of cell wall biogenesis and principles of antibiotic resistance at the molecular level may open up new frontiers in research on enterococci, particularly for the development of novel antimicrobial strategies. In this article, we outline the current knowledge on the most important antimicrobial resistance mechanisms that involve peptidoglycan synthesis and the role of cell wall constituents, including lipoteichoic acid, wall teichoic acid, capsular polysaccharides, LPxTG cell wall-anchored surface proteins, WxL-type surface proteins and pili, in the pathogenesis of E. faecium.
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Affiliation(s)
- Antoni P A Hendrickx
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.
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Lessa S, Paes R, Santoro P, Mauro R, Vieira-da-Motta O. Identification and antimicrobial resistance of microflora colonizing feral pig (Sus scrofa) of Brazilian Pantanal. Braz J Microbiol 2011; 42:740-9. [PMID: 24031689 PMCID: PMC3769837 DOI: 10.1590/s1517-838220110002000042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 01/13/2011] [Indexed: 05/27/2023] Open
Abstract
Antimicrobial resistance of bacteria is a worldwide problem affecting wild life by living with resistant bacteria in the environment. This study presents a discussion of outside factors environment on microflora of feral pigs (Sus scrofa) from Brazilian Pantanal. Animals had samples collected from six different body sites coming from two separated geographic areas, Nhecolandia and Rio Negro regions. With routine biochemical tests and commercial kits 516 bacteria were identified, with 240 Gram-positive, predominantly staphylococci (36) and enterococci (186) strains. Among Gram-negative (GN) bacteria the predominant specimens of Enterobacteriaceae (247) mainly represented by Serratia spp. (105), Escherichia coli (50), and Enterobacter spp. (40) and specimens not identified (7). Antimicrobial susceptibility was tested against 17 drugs by agar diffusion method. Staphylococci were negative to production of enterotoxins and TSST-1, with all strains sensitive towards four drugs and highest resistance toward ampicillin (17%). Enterococci presented the highest sensitivity against vancomycin (98%), ampicillin (94%) and tetracycline (90%), and highest resistance pattern toward oxacillin (99%), clindamycin (83%), and cotrimoxazole (54%). In GN the highest resistance was observed with Serratia marcescens against CFL (98%), AMC (66%) and AMP (60%) and all drugs was most effective against E. coli SUT, TET (100%), AMP, TOB (98%), GEN, CLO (95%), CFO, CIP (93%). The results show a new profile of oxacillin-resistant enterococci from Brazilian feral pigs and suggest a limited residue and spreading of antimicrobials in the environment, possibly because of low anthropogenic impact reflected by the drug susceptibility profile of bacteria isolated.
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Affiliation(s)
- Ss Lessa
- Laboratório de Sanidade Animal, Setor de Doenças Infecto-Contagiosas, Universidade Estadual do Norte Fluminense Darcy Ribeiro , Campos dos Goytacazes, RJ , Brasil
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15
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Bjørkeng E, Rasmussen G, Sundsfjord A, Sjöberg L, Hegstad K, Söderquist B. Clustering of polyclonal VanB-type vancomycin-resistant Enterococcus faecium in a low-endemic area was associated with CC17-genogroup strains harbouring transferable vanB2-Tn5382 and pRUM-like repA containing plasmids with axe-txe plasmid addiction systems. APMIS 2011; 119:247-58. [PMID: 21492224 DOI: 10.1111/j.1600-0463.2011.02724.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
VanB-type vancomycin-resistant Enterococcus faecium isolates (n = 17) from 15 patients at the Örebro University hospital in Sweden during a span of 18 months was characterized. All patients had underlying disorders and received broad-spectrum antimicrobial therapy. Pulsed-field gel electrophoresis (PFGE) grouped 14 isolates in three PFGE types and three isolates in unique PFGE patterns. All isolates had multi-locus sequence types [ST17 (n = 5); ST18 (n = 3); ST125 (n = 7); ST262 (n = 1); ST460 (n = 1)] belonging to the successful hospital-adapted clonal complex 17 (CC17), harboured CC17-associated virulence genes, were vanB2-positive and expressed diverse vancomycin minimum inhibitory concentration (MICs; 8 to > 256 mg/L). Isolate 1 had a unique PFGE type and a chromosomal transferable vanB2-Tn5382 element. Interestingly, the other five PFGE types had Tn5382 located on plasmids containing pRUM-like repA and a plasmid addiction system (axe-txe) shown by co-hybridization analysis of PFGE-separated S1-nuclease digested total DNA. The resistance plasmids were mainly of 120-kb and supported intraspecies vanB transfer. Two strains were isolated from patient 6 and we observed a possible transfer of the vanB2-resistance genes from PFGE type III ST460 to a more successful PFGE type I ST125. This latter PFGE type I ST125 became the predominant type afterwards. Our observations support the notion that vanB-type vancomycin-resistant Enterococcus faecium can persist in a low-endemic area through successful clones and plasmids with stability functions in hospital patients with known risk factors.
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Affiliation(s)
- Eva Bjørkeng
- Research Group for Host-Microbe Interactions, Department of Medical Biology, University of Tromsø, Norway
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Hegstad K, Mikalsen T, Coque TM, Werner G, Sundsfjord A. Mobile genetic elements and their contribution to the emergence of antimicrobial resistant Enterococcus faecalis and Enterococcus faecium. Clin Microbiol Infect 2011; 16:541-54. [PMID: 20569265 DOI: 10.1111/j.1469-0691.2010.03226.x] [Citation(s) in RCA: 234] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mobile genetic elements (MGEs) including plasmids and transposons are pivotal in the dissemination and persistence of antimicrobial resistance in Enterococcus faecalis and Enterococcus faecium. Enterococcal MGEs have also been shown to be able to transfer resistance determinants to more pathogenic bacteria such as Staphylococcus aureus. Despite their importance, we have a limited knowledge about the prevalence, distribution and genetic content of specific MGEs in enterococcal populations. Molecular epidemiological studies of enterococcal MGEs have been hampered by the lack of standardized molecular typing methods and relevant genome information. This review focuses on recent developments in the detection of MGEs and their contribution to the spread of antimicrobial resistance in clinically relevant enterococci.
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Affiliation(s)
- K Hegstad
- Reference Centre for Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North-Norway.
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Rosvoll TC, Pedersen T, Sletvold H, Johnsen PJ, Sollid JE, Simonsen GS, Jensen LB, Nielsen KM, Sundsfjord A. PCR-based plasmid typing inEnterococcus faeciumstrains reveals widely distributed pRE25-, pRUM-, pIP501- and pHTβ-related replicons associated with glycopeptide resistance and stabilizing toxin–antitoxin systems. ACTA ACUST UNITED AC 2010; 58:254-68. [DOI: 10.1111/j.1574-695x.2009.00633.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Isolation of VanB-type Enterococcus faecalis strains from nosocomial infections: first report of the isolation and identification of the pheromone-responsive plasmids pMG2200, Encoding VanB-type vancomycin resistance and a Bac41-type bacteriocin, and pMG2201, encoding erythromycin resistance and cytolysin (Hly/Bac). Antimicrob Agents Chemother 2008; 53:735-47. [PMID: 19029325 DOI: 10.1128/aac.00754-08] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Eighteen identical VanB-type Enterococcus faecalis isolates that were obtained from different hospitalized patients were examined for their drug resistance and plasmid DNAs. Of the 18 strains, 12 strains exhibited resistance to erythromycin (Em), gentamicin (Gm), kanamycin (Km), tetracycline (Tc), and vancomycin (Van) and produced cytolysin (Hly/Bac) and a bacteriocin (Bac) active against E. faecalis strains. Another six of the strains exhibited resistance to Gm, Km, Tc, and Van and produced a bacteriocin. Em and Van resistance was transferred individually to E. faecalis FA2-2 strains at a frequency of about 10(-4) per donor cell by broth mating. The Em-resistant transconjugants and the Van-resistant transconjugants harbored a 65.7-kbp plasmid and a 106-kbp plasmid, respectively. The 106-kbp and 65.7-kbp plasmids isolated from the representative E. faecalis NKH15 strains were designated pMG2200 and pMG2201, respectively. pMG2200 conferred vancomycin resistance and bacteriocin activity on the host strain and responded to the synthetic pheromone cCF10 for pCF10, while pMG2201 conferred erythromycin resistance and cytolysin activity on its host strain and responded to the synthetic pheromone cAD1 for pAD1. The complete DNA sequence of pMG2200 (106,527 bp) showed that the plasmid carried a Tn1549-like element encoding vanB2-type resistance and the Bac41-like bacteriocin genes of pheromone-responsive plasmid pYI14. The plasmid contained the regulatory region found in pheromone-responsive plasmids and encoded the genes prgX and prgQ, which are the key negative regulatory elements for plasmid pCF10. pMG2200 also encoded TraE1, a key positive regulator of plasmid pAD1, indicating that pMG2200 is a naturally occurring chimeric plasmid that has a resulting prgX-prgQ-traE1 genetic organization in the regulatory region of the pheromone response. The functional oriT region and the putative relaxase gene of pMG2200 were identified and found to differ from those of pCF10 and pAD1. The putative relaxase of pMG2200 was classified as a member of the MOB(MG) family, which is found in pheromone-independent plasmid pHTbeta of the pMG1-like plasmids. This is the first report of the isolation and characterization of a pheromone-responsive highly conjugative plasmid encoding vanB resistance.
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Werner G, Strommenger B, Witte W. Acquired vancomycin resistance in clinically relevant pathogens. Future Microbiol 2008; 3:547-62. [DOI: 10.2217/17460913.3.5.547] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Acquired resistance to vancomycin is an increasing problem in pathogenic bacteria. It is best studied and most prevalent among Enterococcus and still remains rare in other pathogenic bacteria. Different genotypes of vancomycin resistance, vanA–G, have been described. The different van gene clusters consist of up to nine genes encoding proteins of different functions; their interplay leads to an alternative cell wall precursor less susceptible to glycopeptide binding. Variants of vanA and vanB types are found worldwide, with vanA predominating; their reservoir is Enterococcus faecium. Within this species a subpopulation of hospital-adapted types exists that acquired van gene clusters and which is responsible for outbreaks of vancomycin-resistant enterococci all over the world. Acquisition of vanA by methicillin-resistant Staphylococcus aureus (MRSA) is worrisome and seven cases have been described. Nonsusceptibility to glycopeptides also occurs independently from van genes and is a growing therapeutic challenge, especially in MRSA.
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Affiliation(s)
- Guido Werner
- FG 13 Nosocomial Infections, Robert Koch Institute, Wernigerode Branch, Burgstr. 37, Wernigerode, 38855, Germany
| | - Birgit Strommenger
- Robert Koch Institute, Wernigerode Branch, Burgstr. 37, Wernigerode, 38855, Germany
| | - Wolfgang Witte
- Robert Koch Institute, Wernigerode Branch, Burgstr. 37, Wernigerode, 38855, Germany
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Dahl KH, Mater DDG, Flores MJ, Johnsen PJ, Midtvedt T, Corthier G, Sundsfjord A. Transfer of plasmid and chromosomal glycopeptide resistance determinants occurs more readily in the digestive tract of mice than in vitro and exconjugants can persist stably in vivo in the absence of glycopeptide selection. J Antimicrob Chemother 2007; 59:478-86. [PMID: 17283034 DOI: 10.1093/jac/dkl530] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES AND METHODS The transferability of vanA and vanB glycopeptide resistance determinants with a defined plasmid (n = 9) or chromosomal (n = 4) location between Enterococcus faecium strains of human and animal origins was compared using filter mating (in vitro) and germ-free mice (in vivo) as experimental models. Moreover, the stability of exconjugants in vivo in the absence of antibiotic selection was examined. RESULTS Higher transfer rates were observed in vivo for four of six vanA and five of six vanB donor strains. For plasmid-encoded resistance, several log higher transfer frequencies were observed in vivo for some strains. Moreover, the in vivo model supported transfer of plasmid-encoded vanB (1 x 10(-7) exconjugants/donor) when repeated in vitro experiments were negative (estimated < 1 x 10(-9) exconjugants/donor). Readily detectable transfer of plasmid-located vanA and vanB as well as large chromosomal (>200 kb) vanB elements was observed after 24 h. The number of plasmid-mediated vanA exconjugants generally decreased markedly after 3 days. However, exconjugants containing a plasmid harbouring the vanA transposon Tn1546 linked to the post-segregational killing system omega-epsilon-zeta persisted stably in vivo in the absence of glycopeptides for more than 20 days. CONCLUSIONS The overall results support the notion that the in vitro model underestimates the transfer potential. Rapid transfer of vanA plasmids from poultry- and pig-derived strains to human faecal E. faecium shows that even transiently colonizing strains may provide a significant reservoir for transfer of resistance genes to the permanent commensal flora. Newly acquired resistance genes may be stabilized and persist in new populations in the absence of antibiotic selection.
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21
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Abstract
The first vancomycin-resistant clinical isolates of Enterococcus species were reported in Europe in 1988. Similar strains were later detected in hospitals on the East Coast of the United States. Since then, vancomycin-resistant enterococci have spread with unexpected rapidity and are now encountered in hospitals in most countries. This article reviews the mode of action and the mechanism of bacterial resistance to glycopeptides, as exemplified by the VanA type, which is mediated by transposon Tn1546 and is widely spread in enterococci. The diversity, regulation, evolution, and recent dissemination of methicillin-resistant Staphylococcus aureus are then discussed.
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22
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Launay A, Ballard SA, Johnson PDR, Grayson ML, Lambert T. Transfer of vancomycin resistance transposon Tn1549 from Clostridium symbiosum to Enterococcus spp. in the gut of gnotobiotic mice. Antimicrob Agents Chemother 2006; 50:1054-62. [PMID: 16495268 PMCID: PMC1426432 DOI: 10.1128/aac.50.3.1054-1062.2006] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The vancomycin resistance vanB2 gene cluster is disseminated worldwide and has been found in phylogenetically remote bacterial genera. The vanB2 operon is part of conjugative transposons Tn1549/Tn5382, but conjugative transposition of these elements has not been demonstrated. We have obtained transfer of a Tn1549-like element (referred to herein as "Tn1549-like") from Clostridium symbiosum MLG101 to Enterococcus faecium 64/3 and Enterococcus faecalis JH2-2 in the digestive tract of gnotobiotic mice and to E. faecium 64/3 in vitro. Retransfer of Tn1549-like from an E. faecium transconjugant also containing Tn916 to E. faecium BM77 was obtained in vitro, albeit at a very low frequency. Transfer efficiency was found to be both donor and recipient dependent. Pulsed-field gel electrophoresis analysis of total SmaI-digested DNA of 48 transconjugants indicated in 27 instances the acquisition of ca. 34 kb of DNA. Two transconjugants harbored two copies of the transposon. Sequencing of the flanking regions of Tn1549-like in 48 transconjugants revealed 29 integration events in 26 loci in the E. faecium genome, and two hot spots for insertion were identified. Integration of the transposon was associated with the acquisition of 5 (n = 18) or 6 (n = 7) bp of donor DNA or with 5-bp duplications of target DNA in the remaining transconjugants. These data demonstrate functionality of the Tn1549-like element and attest that the transfer of the vanB operon between enterococci and human commensal anaerobes occurs in the intestinal environment.
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Affiliation(s)
- Aline Launay
- Centre d'Etudes Pharmaceutiques, Châtenay-Malabry, France
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23
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Mathur S, Singh R. Antibiotic resistance in food lactic acid bacteria--a review. Int J Food Microbiol 2005; 105:281-95. [PMID: 16289406 DOI: 10.1016/j.ijfoodmicro.2005.03.008] [Citation(s) in RCA: 396] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Revised: 12/18/2004] [Accepted: 03/20/2005] [Indexed: 10/25/2022]
Abstract
Antibiotics are a major tool utilized by the health care industry to fight bacterial infections; however, bacteria are highly adaptable creatures and are capable of developing resistance to antibiotics. Consequently, decades of antibiotic use, or rather misuse, have resulted in bacterial resistance to many modern antibiotics. This antibiotic resistance can cause significant danger and suffering for many people with common bacterial infections, those once easily treated with antibiotics. For several decades studies on selection and dissemination of antibiotic resistance have focused mainly on clinically relevant species. However, recently many investigators have speculated that commensal bacteria including lactic acid bacteria (LAB) may act as reservoirs of antibiotic resistance genes similar to those found in human pathogens. The main threat associated with these bacteria is that they can transfer resistance genes to pathogenic bacteria. Genes conferring resistance to tetracycline, erythromycin and vancomycin have been detected and characterized in Lactococcus lactis, Enterococci and, recently, in Lactobacillus species isolated from fermented meat and milk products. A number of initiatives have been recently launched by various organizations across the globe to address the biosafety concerns of starter cultures and probiotic microorganisms. The studies can lead to better understanding of the role played by the dairy starter microorganisms in horizontal transfer of antibiotic resistance genes to intestinal microorganisms and food-associated pathogenic bacteria.
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Affiliation(s)
- Shalini Mathur
- National Collection of Dairy Cultures, Dairy Microbiology Division, National Dairy Research Institute, Karnal, PIN 243 122, India
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24
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Depardieu F, Bonora MG, Reynolds PE, Courvalin P. The vanG glycopeptide resistance operon from Enterococcus faecalis revisited. Mol Microbiol 2004; 50:931-48. [PMID: 14617152 DOI: 10.1046/j.1365-2958.2003.03737.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Acquired VanG-type resistance to vancomycin (MIC = 16 micro g ml(-1)) but susceptibility to teicoplanin in Enterococcus faecalis BM4518 and WCH9 is due to the inducible synthesis of peptidoglycan precursors ending in d-alanine-d-serine. The vanG cluster, assigned to a chromosomal location, was composed of genes recruited from various van operons. The 3' end encoded VanG, a d-Ala:d-Ser ligase, VanXY(G), a putative bifunctional d,d-peptidase and VanT(G), a serine racemase: VanG and VanT(G) were implicated in the synthesis of d-Ala:d-Ser as in VanC- and VanE-type strains. Upstream from the structural genes for these proteins were vanW(G) with unknown function and vanY(G) containing a frameshift mutation which resulted in premature termination of the encoded protein and accounted for the lack of UDP-MurNAc-tetrapeptide in the cytoplasm. Without the frameshift mutation, VanY(G) had homology with Zn2+ dependent d,d-carboxypeptidases. The 5' end of the gene cluster contained three genes vanU(G), vanR(G) and vanS(G) encoding a putative regulatory system, which were co-transcribed constitutively from the PY(G) promoter, whereas transcription of vanY(G),W(G),G,XY(G),T(G) was inducible and initiated from the P(YG) promoter. Transfer of VanG-type glycopeptide resistance to E. faecalis JH2-2 was associated with the movement, from chromosome to chromosome, of genetic elements of c. 240 kb carrying also ermB-encoded erythromycin resistance. Sequence determination of the flanking regions of the vanG cluster in donor and transconjugants revealed the same 4 bp direct repeats and 22 bp imperfect inverted repeats that delineated the large element.
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Affiliation(s)
- Florence Depardieu
- Unité des Agents Antibactériens, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, Cedex 15, France
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Bujdáková H, Krupová I, Filipová M, Benczeová S, Kettner M, Drahovská H, Seman M, Bagová M. The occurrence and transferability of the resistance determinants in 50 amikacin-resistant Enterococcus faecalis and Enterococcus faecium. Int J Antimicrob Agents 2003; 22:632-3. [PMID: 14659665 DOI: 10.1016/s0924-8579(03)00247-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Klare I, Konstabel C, Badstübner D, Werner G, Witte W. Occurrence and spread of antibiotic resistances in Enterococcus faecium. Int J Food Microbiol 2003; 88:269-90. [PMID: 14597000 DOI: 10.1016/s0168-1605(03)00190-9] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Enterococci are the second to third most important bacterial genus in hospital infections. Especially Enterococcus (E.) faecium possesses a broad spectrum of natural and acquired antibiotic resistances which are presented in detail in this paper. From medical point of view, the transferable resistances to glycopeptides (e.g., vancomycin, VAN, or teicoplanin, TPL) and streptogramins (e.g., quinupristin/dalfopristin, Q/D) in enterococci are of special interest. The VanA type of enterococcal glycopeptide resistance is the most important one (VAN-r, TPL-r); its main reservoir is E. faecium. Glycopeptide-resistant E. faecium (GREF) can be found in hospitals and outside of them, namely in European commercial animal husbandry in which the glycopeptide avoparcin (AVO) was used as growth promoter in the past. There are identical types of the vanA gene clusters in enterococci from different ecological origins (faecal samples of animals, animal feed, patients in hospitals, persons in the community, waste water samples). Obviously, across the food chain (by GREF-contaminated meat products), these multiple-resistant bacteria or their vanA gene clusters can reach humans. In hospital infections, widespread epidemic-virulent E. faecium isolates of the same clone with or without glycopeptide resistance can occur; these strains often harbour different plasmids and the esp gene. This indicates that hospital-adapted epidemic-virulent E. faecium strains have picked up the vanA gene cluster after they were already widely spread. The streptogramin virginiamycin was also used as feed additive in commercial animal husbandry in Europe for more than 20 years, and it created reservoirs for streptogramin-resistant E. faecium (SREF). In 1998/1999, SREF could be isolated in Germany from waste water of sewage treatment plants, from faecal samples and meat products of animals that were fed virginiamycin (cross resistance to Q/D), from stools of humans in the community, and from clinical samples. These isolations of SREF occurred in a time before the streptogramin combination Q/D was introduced for therapeutic purposes in German hospitals in May 2000, while other streptogramins were not used in German clinics. This seems to indicate that the origin of these SREF or their streptogramin resistance gene(s) originated from other sources outside the hospitals, probably from commercial animal husbandry. In order to prevent the dissemination of multiple antibiotic-resistant enterococci or their transferable resistance genes, a prudent use of antibiotics is necessary in human and veterinary medicine, and in animal husbandry.
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Affiliation(s)
- Ingo Klare
- Robert Koch Institute, Wernigerode Branch, Burgstrasse 37, D-38855 Wernigerode, Germany.
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27
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Dahl KH, Sundsfjord A. Transferable vanB2 Tn5382-containing elements in fecal streptococcal strains from veal calves. Antimicrob Agents Chemother 2003; 47:2579-83. [PMID: 12878522 PMCID: PMC166075 DOI: 10.1128/aac.47.8.2579-2583.2003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Three vancomycin-resistant veal calf fecal streptococci, identified as Streptococcus gallolyticus (n = 2) and Streptococcus lutetiensis, were shown to harbor vanB2 Tn5382-like elements earlier described in enterococci. One S. gallolyticus strain had a 1,495-bp IS256-related element inserted in vanS(B). The vanB2 Tn5382 element present in the plasmid-free S. lutetiensis strain was transferable to Enterococcus faecium BM4105-RF, Enterococcus faecalis JH2-2, and its recombination-deficient derivative, UV202. The transfer frequencies were comparable between recipient strains (from 1 x 10(-7) to 7 x 10(-6)). All transconjugants acquired a vanB-containing chromosomal insert of approximately 100 kb, apparently by site-specific integration. Secondary transconjugants were not observed in intraspecies retransfer experiments. These observations are consistent with a conjugative, selftransmissible, integrative element that might be involved in the interspecies spread of vanB2 resistance determinants. Two JH2-2-derived transconjugants had also gained additional copies of large vanB-containing chromosomal fragments, a process that involves unexplained mechanisms that seems to require functional host cell-dependent recombination mechanisms.
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Affiliation(s)
- Kristin H Dahl
- Department of Microbiology and Virology, University of Tromsø, Norway.
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28
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Grady R, Hayes F. Axe-Txe, a broad-spectrum proteic toxin-antitoxin system specified by a multidrug-resistant, clinical isolate of Enterococcus faecium. Mol Microbiol 2003; 47:1419-32. [PMID: 12603745 DOI: 10.1046/j.1365-2958.2003.03387.x] [Citation(s) in RCA: 177] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Enterococcal species of bacteria are now acknowledged as leading causes of bacteraemia and other serious nosocomial infections. However, surprisingly little is known about the molecular mechanisms that promote the segregational stability of antibiotic resistance and other plasmids in these bacteria. Plasmid pRUM (24 873 bp) is a multidrug resistance plasmid identified in a clinical isolate of Enterococcus faecium. A novel proteic-based toxin-antitoxin cassette identified on pRUM was demonstrated to be a functional segregational stability module in both its native host and evolutionarily diverse bacterial species. Induced expression of the toxin protein (Txe) of this system resulted in growth inhibition in Escherichia coli. The toxic effect of Txe was alleviated by co-expression of the antitoxin protein, Axe. Homologues of the axe and txe genes are present in the genomes of a diversity of Eubacteria. These homologues (yefM-yoeB) present in the E. coli chromosome function as a toxin-antitoxin mechanism, although the Axe and YefM antitoxin components demonstrate specificity for their cognate toxin proteins in vivo. Axe-Txe is one of the first functional proteic toxin-antitoxin systems to be accurately described for Gram-positive bacteria.
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Affiliation(s)
- Ruth Grady
- Department of Biomolecular Sciences, University of Manchester Institute of Science and Technology (UMIST), PO Box 88, Manchester M60 1QD, UK
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29
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Tavares W. [Problems with gram-positive bacteria: resistance in staphylococci, enterococci, and pneumococci to antimicrobial drugs]. Rev Soc Bras Med Trop 2000; 33:281-301. [PMID: 10967598 DOI: 10.1590/s0037-86822000000300008] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The resistance in staphylococci, enterococci, and pneumococci is reviewed. The author also recalls the first cases, and presents an overview of the distribution of cases in the world, the genetic and molecular mechanisms of resistance, the importance in Brazil and therapeutic alternatives. The factors that contribute to the dissemination of these problem bacteria and the measures for their control are emphasized.
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Affiliation(s)
- W Tavares
- Faculdade de Medicina de Teresópolis, Escola de Ciências Médicas de Volta Redonda, RJ, Brasil
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Abstract
Cycling of currently available antibiotics to reduce resistance is an attractive concept. For cycling strategies to be successful, their implementation must have a demonstrable impact on the prevalence of resistance determinants already dispersed throughout the hospital and associated healthcare facilities. While antibiotic use in hospitals clearly constitutes a stimulus for the emergence of resistance, it is by no means the only important factor. The incorporation of resistance determinants into potentially stable genetic structures, including bacteriophages, plasmids, transposons, and the more newly discovered movable elements termed integrons and gene cassettes, forces some degree of skepticism about the potential for such strategies in institutions where resistance determinants are already prevalent. In particular, the expanding role of integrons may pose an ultimate threat to formulary manipulations such as cycling. Despite these concerns, the crisis posed by antimicrobial resistance warrants investigation of any strategy with the potential for reducing the prevalence of resistance. Over the next decade, new studies with carefully designed outcomes should determine the utility of antibiotic cycling as one control measure for nosocomial resistance.
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Affiliation(s)
- J F John
- Division of Allergy, Immunology, and Infectious Diseases, Robert Wood Johnson Medical School, New Brunswick, New Jersey 08903-0019, USA
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Malathum K, Murray BE. Vancomycin-resistant enterococci: recent advances in genetics, epidemiology and therapeutic options. Drug Resist Updat 1999; 2:224-243. [PMID: 11504495 DOI: 10.1054/drup.1999.0098] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Vancomycin-resistant enterococci (VRE) have gained much attention in the last decade. Currently, there are five known types of vancomycin resistance based on genes encoding ligase enzymes that the organisms use to produce their cell wall precursors, namely, VanA, VanB, VanC, VanD and VanE. An additional unclassified type was discovered in Australia. The basis of resistance among these phenotypes appears to be similar in that the resistant organisms produce peptidoglycan precursors that end in moieties other than D-alanyl-D-alanine, the usual target of vancomycin. The other dipeptide-like termini identified to date include D-alanyl-D-lactate and D-alanyl-D-serine, which have low affinity for glycopeptides. Recent evidence suggests that glycopeptide-producing organisms might be the remote origin of the vancomycin resistance genes. In European countries, avoparcin, a glycopeptide used in farm animals as a growth promoter, has been linked to the occurrence of VRE and occasional common strains have been identified in food products, farm animals, healthy subjects and hospitalized patients. There have been no such reports in the USA where heavy use of vancomycin and use of broad spectrum antibiotics such as cephalosporins have been identified as important risk factors for acquisition of VRE. Transmission within the same or between hospitals has been reported in many countries. Infection control measures and efforts to use antibiotics, particularly vancomycin, more appropriately have been implemented in a number of healthcare facilities with varying degrees of success. Many antibiotics, as a single agent or a combination of drugs, as well as various new antibiotics have been tested in vitro, in animal models, or used in anecdotal cases but clinical data from large comparative trials are not available to date. Because of the limited susceptibility of many VRE to other agents, efforts to control these organisms are particularly important. Copyright 1999 Harcourt Publishers LtdCopyright 1999 Harcourt Publishers Ltd.
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Affiliation(s)
- Kumthorn Malathum
- Center for the Study of Emerging and Re-Emerging Pathogens, The University of Texas Medical School at Houston, Houston, TX, 77030, USA
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