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Geraldes C, Tavares L, Gil S, Oliveira M. Antibiotic heteroresistance and persistence: an additional aid in hospital acquired infections by Enterococcus spp.? Future Microbiol 2024:1-12. [PMID: 39229839 DOI: 10.1080/17460913.2024.2393003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 08/13/2024] [Indexed: 09/05/2024] Open
Abstract
Enterococcus, particularly E. faecium and E. faecalis, are responsible for many hospital-acquired infections. With their intrinsic antibiotic resistance and ability to form biofilms, enterococcal infections are already challenging to manage. However, when heterogenous populations are present, such as those exhibiting heteroresistance and persistence, the complexity of these infections increases exponentially not only due to their treatment but also due to their difficult diagnosis. In this study, we provide a summary of the current understanding of both heteroresistance and persistence in terms of mechanisms, diagnosis and treatment and subsequently review recent literature pertaining to these susceptibility types specifically in enterococci.
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Affiliation(s)
- Catarina Geraldes
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- AL4AnimalS - Associate Laboratory for Animal & Veterinary Sciences, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
| | - Luís Tavares
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- AL4AnimalS - Associate Laboratory for Animal & Veterinary Sciences, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
| | - Solange Gil
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- AL4AnimalS - Associate Laboratory for Animal & Veterinary Sciences, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- BICU - Biological Isolation & Containment Unit, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
| | - Manuela Oliveira
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- AL4AnimalS - Associate Laboratory for Animal & Veterinary Sciences, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- cE3c - Centre for Ecology, Evolution & Environmental Changes & CHANGE-Global Change & Sustainability Institute, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
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2
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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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3
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Sangiorgio G, Calvo M, Migliorisi G, Campanile F, Stefani S. The Impact of Enterococcus spp. in the Immunocompromised Host: A Comprehensive Review. Pathogens 2024; 13:409. [PMID: 38787261 PMCID: PMC11124283 DOI: 10.3390/pathogens13050409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Revised: 05/05/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024] Open
Abstract
The immunocompromised host is usually vulnerable to infectious diseases due to broad-spectrum treatments and immunological dysregulation. The Enterococcus genus consists of normal gut commensals, which acquire a leading role in infective processes among individuals with compromised immune systems. These microorganisms may express a potential virulence and resistance spectrum, enabling their function as severe pathogens. The Enterococcus spp. infections in immunocompromised hosts appear to be difficult to resolve due to the immunological response impairment and the possibility of facing antimicrobial-resistant strains. As regards the related risk factors, several data demonstrated that prior antibiotic exposure, medical device insertion, prolonged hospitalization and surgical interventions may lead to Enterococcus overgrowth, antibiotic resistance and spread among critical healthcare settings. Herein, we present a comprehensive review of Enterococcus spp. in the immunocompromised host, summarizing the available knowledge about virulence factors, antimicrobial-resistance mechanisms and host-pathogen interaction. The review ultimately yearns for more substantial support to further investigations about enterococcal infections and immunocompromised host response.
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Affiliation(s)
- Giuseppe Sangiorgio
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy; (F.C.); (S.S.)
| | - Maddalena Calvo
- U.O.C. Laboratory Analysis Unit, University Hospital Policlinico-San Marco, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (G.M.)
| | - Giuseppe Migliorisi
- U.O.C. Laboratory Analysis Unit, University Hospital Policlinico-San Marco, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (G.M.)
| | - Floriana Campanile
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy; (F.C.); (S.S.)
| | - Stefania Stefani
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy; (F.C.); (S.S.)
- U.O.C. Laboratory Analysis Unit, University Hospital Policlinico-San Marco, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (G.M.)
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4
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Chen Z. Mechanisms and Clinical Relevance of Pseudomonas aeruginosa Heteroresistance. Surg Infect (Larchmt) 2023; 24:27-38. [PMID: 36622941 DOI: 10.1089/sur.2022.349] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Abstract Background: Pseudomonas aeruginosa is an opportunistic pathogen that can cause various life-threatening infections. Several unique characteristics make it the ability of survivability and adaptable and develop resistance to antimicrobial agents through multiple mechanisms. Heteroresistance, which is a subpopulation-mediated resistance, has received increasing attention in recent years. Heteroresistance may lead to unexpected treatment failure if not diagnosed in time and treated properly. Therefore, heteroresistant Pseudomonas aeruginosa infections pose considerable problems for hospital-acquired infections. However, the clinical prevalence and implications of Pseudomonas aeruginosa heteroresistance have not been reviewed. Results: In this work, the aspects of the clinically reported heteroresistance of Pseudomonas aeruginosa to commonly used antibiotic agents are reviewed. The prevalence, mechanisms, and clinical relevance of each reported heteroresistant Pseudomonas aeruginosa are discussed.
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Affiliation(s)
- Zhao Chen
- College of Pharmaceutical Science, Collaborative Innovation Center of Yangtza River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, P.R. China
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5
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Mollerup S, Elmeskov C, Pinholt M, Sejersen TS, Pedersen MS, Worning P, Frees D, Westh H. Rapid in vivo development of resistance to daptomycin in vancomycin-resistant Enterococcus faecium due to genomic alterations. FEMS Microbiol Lett 2022; 369:6654877. [PMID: 35922088 DOI: 10.1093/femsle/fnac063] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 06/03/2022] [Accepted: 08/01/2022] [Indexed: 11/14/2022] Open
Abstract
Daptomycin is a cyclic lipopeptide used in the treatment of vancomycin-resistant Enterococcus faecium (VREfm). However, the development of daptomycin-resistant VREfm challenges the treatment of nosocomial VREfm infections. Resistance mechanisms of daptomycin are not fully understood. Here we analysed the genomic changes leading to a daptomycin-susceptible VREfm isolate becoming resistant after 50 days of daptomycin and linezolid combination therapy. Seven isogenic VREfm isolates from the same patient (daptomycin-susceptible and daptomycin-resistant) were analysed using Illumina whole genome sequencing, and two isolates were further characterised with Nanopore sequencing. One nonsynonymous SNP in the rpoC gene previously shown to harbour mutations in daptomycin-resistant VREfm was identified in the daptomycin-resistant isolates. Whole genome comparative analysis identified the loss of a 46.5 kb fragment, duplication of a 29.7 kb fragment, and integration of two plasmids upon acquisition of daptomycin resistance. Transmission electron microscopy showed similar alterations in cell morphology and cell wall structure as have previously been described in daptomycin-resistant Enterococcus faecalis.
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Affiliation(s)
- Sarah Mollerup
- Department of Clinical Microbiology, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
| | - Christine Elmeskov
- Department of Clinical Microbiology, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark.,Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg Denmark
| | - Mette Pinholt
- Department of Clinical Microbiology, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
| | - Tobias Steen Sejersen
- Core Facility for Integrated Microscopy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Martin Schou Pedersen
- Department of Clinical Microbiology, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
| | - Peder Worning
- Department of Clinical Microbiology, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark
| | - Dorte Frees
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg Denmark
| | - Henrik Westh
- Department of Clinical Microbiology, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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6
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Boumasmoud M, Dengler Haunreiter V, Schweizer TA, Meyer L, Chakrakodi B, Schreiber PW, Seidl K, Kühnert D, Kouyos RD, Zinkernagel AS. Genomic Surveillance of Vancomycin-Resistant Enterococcus faecium Reveals Spread of a Linear Plasmid Conferring a Nutrient Utilization Advantage. mBio 2022; 13:e0377121. [PMID: 35343787 PMCID: PMC9040824 DOI: 10.1128/mbio.03771-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 02/25/2022] [Indexed: 12/12/2022] Open
Abstract
Healthcare-associated outbreaks of vancomycin-resistant Enterococcus faecium (VREfm) are a worldwide problem with increasing prevalence. The genomic plasticity of this hospital-adapted pathogen contributes to its efficient spread despite infection control measures. Here, we aimed to identify the genomic and phenotypic determinants of health care-associated transmission of VREfm. We assessed the VREfm transmission networks at the tertiary-care University Hospital of Zurich (USZ) between October 2014 and February 2018 and investigated microevolutionary dynamics of this pathogen. We performed whole-genome sequencing for the 69 VREfm isolates collected during this time frame and assessed the population structure and variability of the vancomycin resistance transposon. Phylogenomic analysis allowed us to reconstruct transmission networks and to unveil external or wider transmission networks undetectable by routine surveillance. Notably, it unveiled a persistent clone, sampled 31 times over a 29-month period. Exploring the evolutionary dynamics of this clone and characterizing the phenotypic consequences revealed the spread of a variant with decreased daptomycin susceptibility and the acquired ability to utilize N-acetyl-galactosamine (GalNAc), one of the primary constituents of the human gut mucins. This nutrient utilization advantage was conferred by a novel plasmid, termed pELF_USZ, which exhibited a linear topology. This plasmid, which was harbored by two distinct clones, was transferable by conjugation. Overall, this work highlights the potential of combining epidemiological, functional genomic, and evolutionary perspectives to unveil adaptation strategies of VREfm. IMPORTANCE Sequencing microbial pathogens causing outbreaks has become a common practice to characterize transmission networks. In addition to the signal provided by vertical evolution, bacterial genomes harbor mobile genetic elements shared horizontally between clones. While macroevolutionary studies have revealed an important role of plasmids and genes encoding carbohydrate utilization systems in the adaptation of Enterococcus faecium to the hospital environment, mechanisms of dissemination and the specific function of many of these genetic determinants remain to be elucidated. Here, we characterize a plasmid providing a nutrient utilization advantage and show evidence for its clonal and horizontal spread at a local scale. Further studies integrating epidemiological, functional genomics, and evolutionary perspectives will be critical to identify changes shaping the success of this pathogen.
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Affiliation(s)
- Mathilde Boumasmoud
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Vanina Dengler Haunreiter
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Tiziano A. Schweizer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Lilly Meyer
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Bhavya Chakrakodi
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Peter W. Schreiber
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Kati Seidl
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Denise Kühnert
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Roger D. Kouyos
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Annelies S. Zinkernagel
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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7
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Paul K, Merabishvili M, Hazan R, Christner M, Herden U, Gelman D, Khalifa L, Yerushalmy O, Coppenhagen-Glazer S, Harbauer T, Schulz-Jürgensen S, Rohde H, Fischer L, Aslam S, Rohde C, Nir-Paz R, Pirnay JP, Singer D, Muntau AC. Bacteriophage Rescue Therapy of a Vancomycin-Resistant Enterococcus faecium Infection in a One-Year-Old Child following a Third Liver Transplantation. Viruses 2021; 13:1785. [PMID: 34578366 PMCID: PMC8472888 DOI: 10.3390/v13091785] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/21/2021] [Accepted: 09/01/2021] [Indexed: 12/23/2022] Open
Abstract
Phage therapy is an experimental therapeutic approach used to target multidrug-resistant bacterial infections. A lack of reliable data with regard to its efficacy and regulatory hurdles hinders a broad application. Here we report, for the first time, a case of vancomycin-resistant Enterococcus faecium abdominal infection in a one-year-old, critically ill, and three times liver transplanted girl, which was successfully treated with intravenous injections (twice per day for 20 days) of a magistral preparation containing two Enterococcus phages. This correlated with a reduction in baseline C-reactive protein (CRP), successful weaning from mechanical ventilation and without associated clinical adverse events. Prior to clinical use, phage genome was sequenced to confirm the absence of genetic determinants conferring lysogeny, virulence or antibiotic resistance, and thus their safety. Using a phage neutralization assay, no neutralizing anti-phage antibodies in the patient's serum could be detected. Vancomycin-susceptible E. faecium isolates were identified in close relation to phage therapy and, by using whole-genome sequencing, it was demonstrated that vancomycin-susceptible E. faecium emerged from vancomycin-resistant progenitors. Covering a one year follow up, we provide further evidence for the feasibility of bacteriophage therapy that can serve as a basis for urgently needed controlled clinical trials.
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Affiliation(s)
- Kevin Paul
- Department of Pediatrics, Kinder-UKE, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (T.H.); (S.S.-J.); (D.S.); (A.C.M.)
| | - Maya Merabishvili
- Burn Centre, Laboratory for Molecular and Cellular Technology (LabMCT), Queen Astrid Military Hospital, B-1120 Brussels, Belgium;
| | - Ronen Hazan
- Institute of Dental Sciences, School of Dentistry, Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (D.G.); (L.K.); (O.Y.); (S.C.-G.)
| | - Martin Christner
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (M.C.); (H.R.)
| | - Uta Herden
- Department of Visceral Transplantation, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (U.H.); (L.F.)
| | - Daniel Gelman
- Institute of Dental Sciences, School of Dentistry, Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (D.G.); (L.K.); (O.Y.); (S.C.-G.)
| | - Leron Khalifa
- Institute of Dental Sciences, School of Dentistry, Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (D.G.); (L.K.); (O.Y.); (S.C.-G.)
| | - Ortal Yerushalmy
- Institute of Dental Sciences, School of Dentistry, Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (D.G.); (L.K.); (O.Y.); (S.C.-G.)
| | - Shunit Coppenhagen-Glazer
- Institute of Dental Sciences, School of Dentistry, Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (D.G.); (L.K.); (O.Y.); (S.C.-G.)
| | - Theresa Harbauer
- Department of Pediatrics, Kinder-UKE, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (T.H.); (S.S.-J.); (D.S.); (A.C.M.)
| | - Sebastian Schulz-Jürgensen
- Department of Pediatrics, Kinder-UKE, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (T.H.); (S.S.-J.); (D.S.); (A.C.M.)
| | - Holger Rohde
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (M.C.); (H.R.)
| | - Lutz Fischer
- Department of Visceral Transplantation, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (U.H.); (L.F.)
| | - Saima Aslam
- Center for Innovative Phage Applications and Therapeutics, Division of Infectious Diseases and Global Public Health, University of California, San Diego, CA 92093, USA;
| | - Christine Rohde
- Leibniz Institute DSMZ—German Collection of Microorganisms and Cell Cultures GmbH, 38124 Braunschweig, Germany;
| | - Ran Nir-Paz
- Department of Clinical Microbiology and Infectious Disease, Hadassah University Medical Center, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112001, Israel;
| | - Jean-Paul Pirnay
- Burn Centre, Laboratory for Molecular and Cellular Technology (LabMCT), Queen Astrid Military Hospital, B-1120 Brussels, Belgium;
| | - Dominique Singer
- Department of Pediatrics, Kinder-UKE, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (T.H.); (S.S.-J.); (D.S.); (A.C.M.)
| | - Ania Carolina Muntau
- Department of Pediatrics, Kinder-UKE, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (T.H.); (S.S.-J.); (D.S.); (A.C.M.)
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8
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Rodríguez-Noriega E, Hernández-Morfin N, Garza-Gonzalez E, Bocanegra-Ibarias P, Flores-Treviño S, Esparza-Ahumada S, González-Díaz E, Pérez-Gómez HR, Mendoza-Mujica C, León-Garnica G, Morfín-Otero R. Risk factors and outcome associated with the acquisition of linezolid-resistant Enterococcus faecalis. J Glob Antimicrob Resist 2020; 21:405-409. [DOI: 10.1016/j.jgar.2020.01.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/25/2019] [Accepted: 01/13/2020] [Indexed: 01/13/2023] Open
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9
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Moure Z, Lara N, Marín M, Sola-Campoy PJ, Bautista V, Gómez-Bertomeu F, Gómez-Dominguez C, Pérez-Vázquez M, Aracil B, Campos J, Cercenado E, Oteo-Iglesias J. Interregional spread in Spain of linezolid-resistant Enterococcus spp. isolates carrying the optrA and poxtA genes. Int J Antimicrob Agents 2020; 55:105977. [PMID: 32330583 DOI: 10.1016/j.ijantimicag.2020.105977] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 03/11/2020] [Accepted: 04/06/2020] [Indexed: 12/12/2022]
Abstract
The emergence of linezolid-resistant Enterococcus spp. (LRE) due to transferable resistance determinants is a matter of concern. To understand the contribution of the plasmid-encoded optrA and poxtA genes to the emergence of LRE, clinical isolates from different Spanish hospitals submitted to the Spanish Reference Laboratory from 2015-2018 were analysed. Linezolid resistance mechanisms were screened in all isolates by PCR and sequencing. Genetic relatedness of Enterococcus spp. carrying optrA and poxtA was studied by PFGE and MLST. Antimicrobial susceptibility was tested by broth microdilution using EUCAST standards. A total of 97 LRE isolates were studied, in 94 (96.9%) of which at least one resistance determinant was detected; 84/97 isolates (86.6%) presented a single resistance mechanism as follows: 45/84 (53.6%) carried the optrA gene, 38/84 (45.2%) carried the G2576T mutation and 1/84 (1.2%) carried the poxtA gene. In addition, 5/97 isolates (5.2%) carried both optrA and the G2576T mutation and 5/97 (5.2%) carried both optrA and poxtA. The optrA gene was more frequent in Enterococcus faecalis (83.6%) than Enterococcus faecium (11.1%) and was mainly associated with community-acquired urinary tract infections. Carriage of the poxtA gene was more frequent in E. faecium (13.9%) than E. faecalis (1.6%). Among the optrA-positive E. faecalis isolates, two main clusters were detected by PFGE. These two clusters belonged to ST585 and ST480 and were distributed throughout 11 and 6 Spanish provinces, respectively. This is the first description of LRE carrying the poxtA gene in Spain, including the co-existence of optrA and poxtA in five isolates.
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Affiliation(s)
- Zaira Moure
- Laboratorio de Referencia e Investigación en Resistencia a Antibióticos e Infecciones Relacionadas con la Asistencia Sanitaria, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain; Spanish Network for Research in Infectious Diseases (REIPI RD16/0016), Instituto de Salud Carlos III, Madrid, Spain
| | - Noelia Lara
- Laboratorio de Referencia e Investigación en Resistencia a Antibióticos e Infecciones Relacionadas con la Asistencia Sanitaria, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Mercedes Marín
- Microbiology Department, Hospital Gregorio Marañón, Madrid, Spain
| | - Pedro J Sola-Campoy
- Laboratorio de Referencia e Investigación en Resistencia a Antibióticos e Infecciones Relacionadas con la Asistencia Sanitaria, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Verónica Bautista
- Laboratorio de Referencia e Investigación en Resistencia a Antibióticos e Infecciones Relacionadas con la Asistencia Sanitaria, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | | | - Cristina Gómez-Dominguez
- Laboratorio de Referencia e Investigación en Resistencia a Antibióticos e Infecciones Relacionadas con la Asistencia Sanitaria, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - María Pérez-Vázquez
- Laboratorio de Referencia e Investigación en Resistencia a Antibióticos e Infecciones Relacionadas con la Asistencia Sanitaria, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain; Spanish Network for Research in Infectious Diseases (REIPI RD16/0016), Instituto de Salud Carlos III, Madrid, Spain
| | - Belén Aracil
- Laboratorio de Referencia e Investigación en Resistencia a Antibióticos e Infecciones Relacionadas con la Asistencia Sanitaria, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain; Spanish Network for Research in Infectious Diseases (REIPI RD16/0016), Instituto de Salud Carlos III, Madrid, Spain
| | - José Campos
- Laboratorio de Referencia e Investigación en Resistencia a Antibióticos e Infecciones Relacionadas con la Asistencia Sanitaria, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain; Spanish Network for Research in Infectious Diseases (REIPI RD16/0016), Instituto de Salud Carlos III, Madrid, Spain
| | - Emilia Cercenado
- Microbiology Department, Hospital Gregorio Marañón, Madrid, Spain
| | - Jesús Oteo-Iglesias
- Laboratorio de Referencia e Investigación en Resistencia a Antibióticos e Infecciones Relacionadas con la Asistencia Sanitaria, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain; Spanish Network for Research in Infectious Diseases (REIPI RD16/0016), Instituto de Salud Carlos III, Madrid, Spain.
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10
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Zhou Y, Yang Y, Ding L, Chen C, Xu X, Wang M. Vancomycin Heteroresistance in vanM-type Enterococcus faecium. Microb Drug Resist 2020; 26:776-782. [PMID: 31951499 DOI: 10.1089/mdr.2019.0321] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although vancomycin heteroresistance exists in enterococci, it is not easily detected using routine methods and the mechanism is not clearly understood. In this study, we characterized the molecular mechanism underlying vancomycin heteroresistance in a clinical vanM-type Enterococcus faecium strain. The original E. faecium isolate, hVREm7, was susceptible to vancomycin by broth microdilution and Etest. However, vancomycin-resistant subcolonies were present within the Etest zone of inhibition. Three passages of hVREm7 were carried out to eliminate the possibility of contamination. hVREm7 and three resistant variants were selected to study the heteroresistance mechanism. Sequence analysis revealed that all four strains contained an unaltered vanM cluster. Southern blot analysis showed that vanM was present both chromosomally and extrachromosomally in the three variants, but only extrachromosomally in hVREm7. The size of the vanM-bearing extrachromosomal DNA fragments in the three variants was larger than that in hVREm7, indicating a variation of vanM gene amplification in the variants. Consistently, vanM copy number and expression level were increased in variant strain VREm7-1. These results suggest that partial or complete amplification/transfer of the vanM gene cluster by an as-yet-unidentified mechanism leads to increased copy number and augmented expression of the vanM gene, which contribute to the transformation of vancomycin-heteroresistant E. faecium into high-level vancomycin-resistant variants.
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Affiliation(s)
- Ying Zhou
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.,Key Laboratory of Clinical Pharmacology of Antibiotics, National Health Commission, Shanghai, China
| | - Yang Yang
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.,Key Laboratory of Clinical Pharmacology of Antibiotics, National Health Commission, Shanghai, China
| | - Li Ding
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.,Key Laboratory of Clinical Pharmacology of Antibiotics, National Health Commission, Shanghai, China
| | - Chunhui Chen
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Xiaogang Xu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.,Key Laboratory of Clinical Pharmacology of Antibiotics, National Health Commission, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Minggui Wang
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.,Key Laboratory of Clinical Pharmacology of Antibiotics, National Health Commission, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
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11
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Wardenburg KE, Potter RF, D’Souza AW, Hussain T, Wallace MA, Andleeb S, Burnham CAD, Dantas G. Phenotypic and genotypic characterization of linezolid-resistant Enterococcus faecium from the USA and Pakistan. J Antimicrob Chemother 2019; 74:3445-3452. [PMID: 31504566 PMCID: PMC6857194 DOI: 10.1093/jac/dkz367] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/16/2019] [Accepted: 07/22/2019] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVES Linezolid is an important therapeutic option for the treatment of infections caused by VRE. Linezolid is a synthetic antimicrobial and resistance to this antimicrobial agent remains relatively rare. As a result, data on the comparative genomics of linezolid resistance determinants in Enterococcus faecium are relatively sparse. METHODS To address this knowledge gap in E. faecium, we deployed phenotypic antibiotic susceptibility testing and Illumina WGS on hospital surface (environmental) and clinical isolates from the USA and Pakistan. RESULTS We found complete concordance between isolate source country and mechanism of linezolid resistance, with all the US isolates possessing a 23S rRNA gene mutation and the Pakistan isolates harbouring two to three acquired antibiotic resistance genes. These resistance genes include the recently elucidated efflux-pump genes optrA and poxtA and a novel cfr-like variant. Although there was no difference in the linezolid MIC between the US and Pakistan isolates, there was a significant difference in the geometric mean of the MIC between the Pakistan isolates that had two versus three of the acquired antibiotic resistance genes. In five of the Pakistan E. faecium that possessed all three of the resistance genes, we found no difference in the local genetic context of poxtA and the cfr-like gene, but we identified different genetic contexts surrounding optrA. CONCLUSIONS These results demonstrate that E. faecium from different geographical regions employ alternative strategies to counter selective pressure of increasing clinical linezolid use.
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Affiliation(s)
- Kate E Wardenburg
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University in St Louis School of Medicine, St Louis, MO, USA
| | - Robert F Potter
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University in St Louis School of Medicine, St Louis, MO, USA
| | - Alaric W D’Souza
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University in St Louis School of Medicine, St Louis, MO, USA
| | - Tahir Hussain
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University in St Louis School of Medicine, St Louis, MO, USA
- Atta ur Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Meghan A Wallace
- Department of Pathology and Immunology, Washington University in St Louis School of Medicine, St Louis, MO, USA
| | - Saadia Andleeb
- Atta ur Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Carey-Ann D Burnham
- Department of Pathology and Immunology, Washington University in St Louis School of Medicine, St Louis, MO, USA
- Departments of Pediatrics and Medicine, Washington University in St Louis School of Medicine, St Louis, MO, USA
- Department of Molecular Microbiology, Washington University in St Louis School of Medicine, St Louis, MO, USA
| | - Gautam Dantas
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University in St Louis School of Medicine, St Louis, MO, USA
- Department of Pathology and Immunology, Washington University in St Louis School of Medicine, St Louis, MO, USA
- Department of Molecular Microbiology, Washington University in St Louis School of Medicine, St Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St Louis, St Louis, MO, USA
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12
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Lee RS, Gonçalves da Silva A, Baines SL, Strachan J, Ballard S, Carter GP, Kwong JC, Schultz MB, Bulach DM, Seemann T, Stinear TP, Howden BP. The changing landscape of vancomycin-resistant Enterococcus faecium in Australia: a population-level genomic study. J Antimicrob Chemother 2019; 73:3268-3278. [PMID: 30189014 DOI: 10.1093/jac/dky331] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/23/2018] [Indexed: 12/17/2022] Open
Abstract
Background Vancomycin-resistant Enterococcus faecium (VREfm) represent a major source of nosocomial infection worldwide. In Australia, there has been a recent concerning increase in bacteraemia associated with the vanA genotype, prompting investigation into the genomic epidemiology of VREfm. Methods A population-level study of VREfm (10 November-9 December 2015) was conducted. A total of 321 VREfm isolates (from 286 patients) across Victoria State were collected and sequenced with Illumina NextSeq. SNPs were used to assess relatedness. STs and genes associated with resistance and virulence were identified. The vanA-harbouring plasmid from an isolate from each ST was assembled using long-read data. Illumina reads from remaining isolates were then mapped to these assemblies to identify their probable vanA-harbouring plasmid. Results vanA-VREfm comprised 17.8% of isolates. ST203, ST80 and a pstS(-) clade, ST1421, predominated (30.5%, 30.5% and 37.2%, respectively). Most vanB-VREfm were ST796 (77.7%). vanA-VREfm were more closely related within hospitals versus between them [core SNPs 10 (IQR 1-357) versus 356 (179-416), respectively], suggesting discrete introductions of vanA-VREfm, with subsequent intra-hospital transmission. In contrast, vanB-VREfm had similar core SNP distributions within versus between hospitals, due to widespread dissemination of ST796. Different vanA-harbouring plasmids were found across STs. With the exception of ST78 and ST796, Tn1546 transposons also varied. Phylogenetic analysis revealed Australian strains were often interspersed with those from other countries, suggesting ongoing cross-continental transmission. Conclusions Emerging vanA-VREfm in Australia is polyclonal, indicating repeat introductions of vanA-VREfm into hospitals and subsequent dissemination. The close relationship to global strains reinforces the need for ongoing screening and control of VREfm in Australia and abroad.
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Affiliation(s)
- Robyn S Lee
- The Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Level 1, Melbourne, Victoria, Australia.,Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T. H. Chan School of Public Health, 677 Huntington Avenue, Level 5, Boston, MA, USA
| | - Anders Gonçalves da Silva
- The Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Level 1, Melbourne, Victoria, Australia
| | - Sarah L Baines
- Department of Microbiology and Immunology, The University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Level 1, Melbourne, Victoria, Australia
| | - Janet Strachan
- The Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Level 1, Melbourne, Victoria, Australia
| | - Susan Ballard
- The Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Level 1, Melbourne, Victoria, Australia
| | - Glen P Carter
- The Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Level 1, Melbourne, Victoria, Australia
| | - Jason C Kwong
- Department of Microbiology and Immunology, The University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Level 1, Melbourne, Victoria, Australia
| | - Mark B Schultz
- The Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Level 1, Melbourne, Victoria, Australia
| | - Dieter M Bulach
- The Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Level 1, Melbourne, Victoria, Australia
| | - Torsten Seemann
- Melbourne Bioinformatics Group, Lab-14, 700 Swanston Street, Carlton, Victoria, Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, The University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Level 1, Melbourne, Victoria, Australia
| | - Benjamin P Howden
- The Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, 792 Elizabeth Street, Level 1, Melbourne, Victoria, Australia.,Infectious Diseases Department, Austin Health, Studley Rd, Heidelberg, Victoria, Australia
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13
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Yang X, Yuan T, Ma R, Chacko KI, Smith M, Deikus G, Sebra R, Kasarskis A, van Bakel H, Franzblau SG, Sampson NS. Mce3R Stress-Resistance Pathway Is Vulnerable to Small-Molecule Targeting That Improves Tuberculosis Drug Activities. ACS Infect Dis 2019; 5:1239-1251. [PMID: 31012313 PMCID: PMC6630528 DOI: 10.1021/acsinfecdis.9b00099] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
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One-third of the world’s population
carries Mycobacterium tuberculosis (Mtb), the infectious agent that causes tuberculosis (TB), and every
17 s someone dies of TB. After infection, Mtb can
live dormant for decades in a granuloma structure arising from the
host immune response, and cholesterol is important for this persistence
of Mtb. Current treatments require long-duration
drug regimens with many associated toxicities, which are compounded
by the high doses required. We phenotypically screened 35 6-azasteroid
analogues against Mtb and found that, at low micromolar
concentrations, a subset of the analogues sensitized Mtb to multiple TB drugs. Two analogues were selected for further study
to characterize the bactericidal activity of bedaquiline and isoniazid
under normoxic and low-oxygen conditions. These two 6-azasteroids
showed strong synergy with bedaquiline (fractional inhibitory concentration
index = 0.21, bedaquiline minimal inhibitory concentration = 16 nM
at 1 μM 6-azasteroid). The rate at which spontaneous resistance
to one of the 6-azasteroids arose in the presence of bedaquiline was
approximately 10–9, and the 6-azasteroid-resistant
mutants retained their isoniazid and bedaquiline sensitivity. Genes
in the cholesterol-regulated Mce3R regulon were required for 6-azasteroid
activity, whereas genes in the cholesterol catabolism pathway were
not. Expression of a subset of Mce3R genes was down-regulated upon
6-azasteroid treatment. The Mce3R regulon is implicated in stress
resistance and is absent in saprophytic mycobacteria. This regulon
encodes a cholesterol-regulated stress-resistance pathway that we
conclude is important for pathogenesis and contributes to drug tolerance,
and this pathway is vulnerable to small-molecule targeting in live
mycobacteria.
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Affiliation(s)
- Xinxin Yang
- Department of Chemistry, Stony Brook University, 100 John S. Toll Drive, Stony Brook, New York 11794-3400, United States
| | - Tianao Yuan
- Department of Chemistry, Stony Brook University, 100 John S. Toll Drive, Stony Brook, New York 11794-3400, United States
| | - Rui Ma
- Institute for Tuberculosis Research, University of Illinois at Chicago, 833 South Wood Street, 425 PHARM, Chicago, Illinois 60612-7231, United States
| | - Kieran I. Chacko
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1498, New York City, New York 10029, United States
| | - Melissa Smith
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1498, New York City, New York 10029, United States
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1498, New York City, New York, 10029-6574, United States
| | - Gintaras Deikus
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1498, New York City, New York 10029, United States
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1498, New York City, New York, 10029-6574, United States
| | - Robert Sebra
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1498, New York City, New York 10029, United States
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1498, New York City, New York, 10029-6574, United States
| | - Andrew Kasarskis
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1498, New York City, New York 10029, United States
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1498, New York City, New York, 10029-6574, United States
| | - Harm van Bakel
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1498, New York City, New York 10029, United States
- Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1498, New York City, New York, 10029-6574, United States
| | - Scott G. Franzblau
- Institute for Tuberculosis Research, University of Illinois at Chicago, 833 South Wood Street, 425 PHARM, Chicago, Illinois 60612-7231, United States
| | - Nicole S. Sampson
- Department of Chemistry, Stony Brook University, 100 John S. Toll Drive, Stony Brook, New York 11794-3400, United States
- Institute of Chemical Biology and Drug Discovery, Stony Brook University, 100 John S. Toll Drive, Stony Brook, New York 11794-3400, United States
- Stellenbosch Institute for Advanced Study (STIAS), Wallenberg Research Centre at Stellenbosch University, 10 Marais Street, Stellenbosch 7600, South Africa
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14
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Schuetz AN. Laboratory Antimicrobial Stewardship During an Outbreak of Linezolid- and Vancomycin-resistant Enterococcus faecium Bacteremia. Clin Infect Dis 2019; 69:266-267. [PMID: 30576431 DOI: 10.1093/cid/ciy1023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 11/29/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Audrey N Schuetz
- Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
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15
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Retrospective analysis of diabetic foot osteomyelitis management and outcome at a tertiary care hospital in the UK. PLoS One 2019; 14:e0216701. [PMID: 31095593 PMCID: PMC6522026 DOI: 10.1371/journal.pone.0216701] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 04/26/2019] [Indexed: 11/19/2022] Open
Abstract
Objectives This study aimed to analyse retrospectively management and outcomes of the diabetic foot osteomyelitis (DFOM) multi-disciplinary team at St Thomas’ Hospital, London. Methods Patients admitted during 2015 with diagnosis of DFOM were included. Data were obtained from medical and microbiology records. Results 275 patients were admitted for DF infection in 2015: 45.1% had OM (75% males). 40% were newly diagnosed with DF ulcer (DFU). 81% patients had X-ray and 28% had MRI. Bone infection was confirmed by MC&S in 53% cases. 930 microbiological isolates were obtained: 63% were Gram-positive microorganisms [S.aureus and MRSA (~40%), CoNS (20%), and E.faecalis (8%)]. All MRSA were vancomycin and linezolid sensitive. 23.2% isolates were vancomycin-resistant enterococci. 24% isolates were Gram-negative organisms: P.aeruginosa (42%), E.coli (13%), and E.cloacae (12%). Meropenem resistance was low; 5.4% P.aeruginosa, 87.5% A.baumanii. 76% patients received co-amoxiclav; 41% received ≥3 antibiotics; 17% received >3 months antibiotics. Hospital mean-length of stay was 26.1 days. Ulcer time-to-heal was >6 months in 25% patients. 22% ulcers healed without surgery, 60% healed after minor amputation, 12% patients had major amputation. Conclusion Despite current MDT approach, many patients progress to amputation. DF-OM still represents a challenging clinical condition, requiring further study to develop better management guidelines.
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16
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Draft Genome Sequences of 48 Vancomycin-Resistant Enterococcus faecium Strains Isolated from Inpatients with Bacteremia and Urinary Tract Infection. Microbiol Resour Announc 2019; 8:8/15/e00222-19. [PMID: 30975810 PMCID: PMC6460033 DOI: 10.1128/mra.00222-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Vancomycin-resistant Enterococcus faecium (VREfm) is a major cause of nosocomial infections of the bloodstream and urinary tract. Here, we report the draft genome sequences of 48 vancomycin-resistant E. faecium isolates recovered from inpatients exhibiting clinical signs of bacteremia at the University of Arkansas for Medical Sciences (UAMS).
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17
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Evolution and mutations predisposing to daptomycin resistance in vancomycin-resistant Enterococcus faecium ST736 strains. PLoS One 2018; 13:e0209785. [PMID: 30576392 PMCID: PMC6303062 DOI: 10.1371/journal.pone.0209785] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 12/11/2018] [Indexed: 12/16/2022] Open
Abstract
We recently identified a novel vancomycin-resistant Enterococcus faecium (VREfm) clone ST736 with reduced daptomycin susceptibility. The objectives of this study were to assess the population dynamics of local VREfm strains and genetic alterations predisposing to daptomycin resistance in VREfm ST736 strains. Multilocus sequence typing and single nucleotide variant data were derived from whole-genome sequencing of 250 E. faecium isolates from 1994–1995 (n = 43), 2009–2012 (n = 115) and 2013 (n = 92). A remarkable change was noticed in the clonality and antimicrobial resistance profiles of E. faecium strains between 1994–1995 and 2013. VREfm sequence type 17 (ST17), the prototype strain of clade A1, was the dominant clone (76.7%) recognized in 1994–1995. By contrast, clone ST736 accounted for 46.7% of VREfm isolates, followed by ST18 (26.1%) and ST412 (20.7%) in 2013. Bayesian evolutionary analysis suggested that clone ST736 emerged between 1996 and 2009. Co-mutations (liaR.W73C and liaS.T120A) of the liaFSR system were identified in all ST736 isolates (n = 111, 100%) examined. Thirty-eight (34.2%) ST736 isolates exhibited daptomycin-resistant phenotype, of which 13 isolates had mutations in both the liaFSR and cardiolipin synthase (cls) genes and showed high level of resistance with a daptomycin MIC50 of 32 μg/mL. The emergence of ST736 strains with mutations predisposing to daptomycin resistance and subsequent clonal spread among inpatients contributed to the observed high occurrence of daptomycin resistance in VREfm at our institution. The expanding geographic distribution of ST736 strains in other states and countries raises concerns about its global dissemination.
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18
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Genome Plasticity of agr-Defective Staphylococcus aureus during Clinical Infection. Infect Immun 2018; 86:IAI.00331-18. [PMID: 30061376 PMCID: PMC6204747 DOI: 10.1128/iai.00331-18] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/21/2018] [Indexed: 01/05/2023] Open
Abstract
Therapy for bacteremia caused by Staphylococcus aureus is often ineffective, even when treatment conditions are optimal according to experimental protocols. Adapted subclones, such as those bearing mutations that attenuate agr-mediated virulence activation, are associated with persistent infection and patient mortality. Therapy for bacteremia caused by Staphylococcus aureus is often ineffective, even when treatment conditions are optimal according to experimental protocols. Adapted subclones, such as those bearing mutations that attenuate agr-mediated virulence activation, are associated with persistent infection and patient mortality. To identify additional alterations in agr-defective mutants, we sequenced and assembled the complete genomes of clone pairs from colonizing and infected sites of several patients in whom S. aureus demonstrated a within-host loss of agr function. We report that events associated with agr inactivation result in agr-defective blood and nares strain pairs that are enriched in mutations compared to pairs from wild-type controls. The random distribution of mutations between colonizing and infecting strains from the same patient, and between strains from different patients, suggests that much of the genetic complexity of agr-defective strains results from prolonged infection or therapy-induced stress. However, in one of the agr-defective infecting strains, multiple genetic changes resulted in increased virulence in a murine model of bloodstream infection, bypassing the mutation of agr and raising the possibility that some changes were selected. Expression profiling correlated the elevated virulence of this agr-defective mutant to restored expression of the agr-regulated ESAT6-like type VII secretion system, a known virulence factor. Thus, additional mutations outside the agr locus can contribute to diversification and adaptation during infection by S. aureus agr mutants associated with poor patient outcomes.
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19
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Update on prevalence and mechanisms of resistance to linezolid, tigecycline and daptomycin in enterococci in Europe: Towards a common nomenclature. Drug Resist Updat 2018; 40:25-39. [DOI: 10.1016/j.drup.2018.10.002] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 08/10/2018] [Accepted: 10/30/2018] [Indexed: 01/04/2023]
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