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Antimicrobial tolerance and its role in the development of resistance: Lessons from enterococci. Adv Microb Physiol 2022; 81:25-65. [PMID: 36167442 DOI: 10.1016/bs.ampbs.2022.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bacteria have developed resistance against every antimicrobial in clinical use at an alarming rate. There is a critical need for more effective use of antimicrobials to both extend their shelf life and prevent resistance from arising. Significantly, antimicrobial tolerance, i.e., the ability to survive but not proliferate during antimicrobial exposure, has been shown to precede the development of bona fide antimicrobial resistance (AMR), sparking a renewed and rapidly increasing interest in this field. As a consequence, problematic infections for the first time are now being investigated for antimicrobial tolerance, with increasing reports demonstrating in-host evolution of antimicrobial tolerance. Tolerance has been identified in a wide array of bacterial species to all bactericidal antimicrobials. Of particular interest are enterococci, which contain the opportunistic bacterial pathogens Enterococcus faecalis and Enterococcus faecium. Enterococci are one of the leading causes of hospital-acquired infection and possess intrinsic tolerance to a number of antimicrobial classes. Persistence of these infections in the clinic is of growing concern, particularly for the immunocompromised. Here, we review current known mechanisms of antimicrobial tolerance, and include an in-depth analysis of those identified in enterococci with implications for both the development and prevention of AMR.
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Evolution of Enterococcus faecium in Response to a Combination of Daptomycin and Fosfomycin Reveals Distinct and Diverse Adaptive Strategies. Antimicrob Agents Chemother 2022; 66:e0233321. [PMID: 35543524 PMCID: PMC9211409 DOI: 10.1128/aac.02333-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Infections caused by vancomycin-resistant Enterococcus faecium (VREfm) are an important public health threat. VREfm isolates have become increasingly resistant to the front-line antibiotic daptomycin (DAP). As such, the use of DAP combination therapies with other antibiotics like fosfomycin (FOS) has received increased attention. Antibiotic combinations could extend the efficacy of currently available antibiotics and potentially delay the onset of further resistance. We investigated the potential for E. faecium HOU503, a clinical VREfm isolate that is DAP and FOS susceptible, to develop resistance to a DAP-FOS combination. Of particular interest was whether the genetic drivers for DAP-FOS resistance might be epistatic and, thus, potentially decrease the efficacy of a combinatorial approach in either inhibiting VREfm or in delaying the onset of resistance. We show that resistance to DAP-FOS could be achieved by independent mutations to proteins responsible for cell wall synthesis for FOS and in altering membrane dynamics for DAP. However, we did not observe genetic drivers that exhibited substantial cross-drug epistasis that could undermine the DAP-FOS combination. Of interest was that FOS resistance in HOU503 was largely mediated by changes in phosphoenolpyruvate (PEP) flux as a result of mutations in pyruvate kinase (pyk). Increasing PEP flux could be a readily accessible mechanism for FOS resistance in many pathogens. Importantly, we show that HOU503 was able to develop DAP resistance through a variety of biochemical mechanisms and was able to employ different adaptive strategies. Finally, we showed that the addition of FOS can prolong the efficacy of DAP and slow down DAP resistance in vitro.
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Contreras GA, Munita JM, Simar S, Luterbach C, Dinh AQ, Rydell K, Sahasrabhojane PV, Rios R, Diaz L, Reyes K, Zervos M, Misikir HM, Sanchez-Petitto G, Liu C, Doi Y, Abbo LM, Shimose L, Seifert H, Gudiol C, Barberis F, Pedroza C, Aitken SL, Shelburne SA, van Duin D, Tran TT, Hanson BM, Arias CA. Contemporary Clinical and Molecular Epidemiology of Vancomycin-Resistant Enterococcal Bacteremia: A Prospective Multicenter Cohort Study (VENOUS I). Open Forum Infect Dis 2021; 9:ofab616. [PMID: 35155713 PMCID: PMC8830530 DOI: 10.1093/ofid/ofab616] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 12/06/2021] [Indexed: 11/25/2022] Open
Abstract
Background Vancomycin-resistant enterococci (VRE) are major therapeutic challenges. Prospective contemporary data characterizing the clinical and molecular epidemiology of VRE bloodstream infections (BSIs) are lacking. Methods The Vancomycin-Resistant Enterococcal BSI Outcomes Study (VENOUS I) is a prospective observational cohort of adult patients with enterococcal BSI in 11 US hospitals. We included patients with Enterococcus faecalis or Enterococcus faecium BSI with ≥1 follow-up blood culture(s) within 7 days and availability of isolate(s) for further characterization. The primary study outcome was in-hospital mortality. Secondary outcomes were mortality at days 4, 7, 10, 12, and 15 after index blood culture. A desirability of outcome ranking was constructed to assess the association of vancomycin resistance with outcomes. All index isolates were subjected to whole genome sequencing. Results Forty-two of 232 (18%) patients died in hospital and 39 (17%) exhibited microbiological failure (lack of clearance in the first 4 days). Neutropenia (hazard ratio [HR], 3.13), microbiological failure (HR, 2.4), VRE BSI (HR, 2.13), use of urinary catheter (HR, 1.85), and Pitt BSI score ≥2 (HR, 1.83) were significant predictors of in-hospital mortality. Microbiological failure was the strongest predictor of in-hospital mortality in patients with E faecium bacteremia (HR, 5.03). The impact of vancomycin resistance on mortality in our cohort changed throughout the course of hospitalization. Enterococcus faecalis sequence type 6 was a predominant multidrug-resistant lineage, whereas a heterogeneous genomic population of E faecium was identified. Conclusions Failure of early eradication of VRE from the bloodstream is a major factor associated with poor outcomes.
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Affiliation(s)
- German A Contreras
- Division of Infectious Diseases, Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, USA
- Center for Antimicrobial Resistance and Microbial Genomics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, USA
- Molecular Genetics and Antimicrobial Resistance Unit, International Center for Microbial Genomics, Universidad El Bosque, Bogotá, Colombia
| | - Jose M Munita
- Center for Antimicrobial Resistance and Microbial Genomics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, USA
- Genomics and Resistant Microbes (GeRM) Group, Facultad de Medicina Clínica Alemana de Santiago, Universidad del Desarrollo, Santiago, Chile
- Millennium Initiative for Collaborative Research On Bacterial Resistance (MICROB-R), Santiago, Chile
| | - Shelby Simar
- Center for Antimicrobial Resistance and Microbial Genomics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, USA
- Center for Infectious Diseases, School of Public Health, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Courtney Luterbach
- Division of Pharmacotherapy and Experimental Therapeutics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - An Q Dinh
- Center for Infectious Diseases Research, Houston Methodist Research Institute, Houston, Texas, USA
| | - Kirsten Rydell
- Division of Infectious Diseases, Houston Methodist Hospital, Houston, Texas, USA
| | | | - Rafael Rios
- Molecular Genetics and Antimicrobial Resistance Unit, International Center for Microbial Genomics, Universidad El Bosque, Bogotá, Colombia
| | - Lorena Diaz
- Molecular Genetics and Antimicrobial Resistance Unit, International Center for Microbial Genomics, Universidad El Bosque, Bogotá, Colombia
| | - Katherine Reyes
- Department of Internal Medicine, Division of Infectious Diseases, Henry Ford Hospital, Detroit, MI, USA
| | - Marcus Zervos
- Department of Internal Medicine, Division of Infectious Diseases, Henry Ford Hospital, Detroit, MI, USA
| | - Helina M Misikir
- Department of Internal Medicine, Division of Infectious Diseases, Henry Ford Hospital, Detroit, MI, USA
| | - Gabriela Sanchez-Petitto
- Department of Medicine, Division of Hematology / Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Catherine Liu
- Department of Medicine, Division of Allergy and Infectious Diseases, School of Medicine, University of Washington, Seattle, WA, USA
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Yohei Doi
- Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Lilian M Abbo
- Division of Infectious Disease, Department of Medicine, University of Miami Miller School of Medicine Miami, Miami, FL, USA
- Jackson Health System, Miami Transplant Institute, Miami, FL, USA
| | - Luis Shimose
- Division of Infectious Disease, Department of Medicine, University of Mississippi Medical Center, Jackson, MS, USA
| | - Harald Seifert
- University of Cologne, Institute for Medical Microbiology, Immunology and Hygiene, University Hospital of Cologne, Cologne, Germany
| | - Carlota Gudiol
- Department of Infectious Diseases, Bellvitge University Hospital, Bellvitge Biomedical Research Institute (IDIBELL), l’Hospitalet de Llobregat, Barcelona, Spain. Spanish Network for Research in Infectious Disease (REIPI), Instituto de Salud Carlos III, Madrid, Spain
| | - Fernanda Barberis
- Unidad de Infectología, Sanatorio Dr. Julio Méndez, CABA. Buenos Aires, Argentina
| | - Claudia Pedroza
- Center for Clinical Research and Evidence-Based Medicine, The University of Texas Health Science Center at Houston, Houston, TX USA
| | - Samuel L Aitken
- Center for Antimicrobial Resistance and Microbial Genomics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, USA
- The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Samuel A Shelburne
- Center for Antimicrobial Resistance and Microbial Genomics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, USA
- The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - David van Duin
- Division of Infectious Diseases, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Truc T Tran
- Center for Infectious Diseases Research, Houston Methodist Research Institute, Houston, Texas, USA
| | - Blake M Hanson
- Center for Antimicrobial Resistance and Microbial Genomics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, USA
- Center for Infectious Diseases, School of Public Health, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Cesar A Arias
- Center for Infectious Diseases Research, Houston Methodist Research Institute, Houston, Texas, USA
- Division of Infectious Diseases, Houston Methodist Hospital, Houston, Texas, USA
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Li L, Higgs C, Turner AM, Nong Y, Gorrie CL, Sherry NL, Dyet KH, Seemann T, Williamson DA, Stinear TP, Howden BP, Carter GP. Daptomycin Resistance Occurs Predominantly in vanA-Type Vancomycin-Resistant Enterococcus faecium in Australasia and Is Associated With Heterogeneous and Novel Mutations. Front Microbiol 2021; 12:749935. [PMID: 34745054 PMCID: PMC8564391 DOI: 10.3389/fmicb.2021.749935] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/28/2021] [Indexed: 11/23/2022] Open
Abstract
Healthcare associated infections caused by vancomycin-resistant Enterococcus faecium (VREfm) have a major impact on health outcomes. VREfm is difficult to treat because of intrinsic and acquired resistance to many clinically used antimicrobials, with daptomycin being one of the few last line therapeutic options for treating multidrug-resistant VREfm. The emergence of daptomycin-resistant VREfm is therefore of serious clinical concern. Despite this, the impact that daptomycin-resistant VREfm have on patient health outcomes is not clearly defined and knowledge on the mechanisms and genetic signatures linked with daptomycin resistance in VREfm remains incomplete. To address these knowledge gaps, phenotypic daptomycin susceptibility testing was undertaken on 324 E. faecium isolates from Australia and New Zealand. Approximately 15% of study isolates were phenotypically resistant to daptomycin. Whole genome sequencing revealed a strong association between vanA-VREfm and daptomycin resistance, with 95% of daptomycin-resistant study isolates harbouring vanA. Genomic analyses showed that daptomycin-resistant VREfm isolates were polyclonal and carried several previously characterised mutations in the liaR and liaS genes as well as several novel mutations within the rpoB, rpoC, and dltC genes. Overall, 70% of daptomycin-resistant study isolates were found to carry mutations within the liaR, rpoB, rpoC, or dltC genes. Finally, in a mouse model of VREfm bacteraemia, infection with the locally dominant daptomycin-resistant clone led to reduced daptomycin treatment efficacy in comparison to daptomycin-susceptible E. faecium. These findings have important implications for ongoing VREfm surveillance activities and the treatment of VREfm infections.
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Affiliation(s)
- Lucy Li
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Charlie Higgs
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Adrianna M Turner
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Yi Nong
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Claire L Gorrie
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia.,Antimicrobial Reference and Research Unit, Microbiological Diagnostic Unit Public Health Laboratory, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Norelle L Sherry
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia.,Antimicrobial Reference and Research Unit, Microbiological Diagnostic Unit Public Health Laboratory, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia.,Department of Infectious Diseases, Austin Health, Melbourne, VIC, Australia
| | - Kristin H Dyet
- The Institute of Environmental Science and Research, Porirua, New Zealand
| | - Torsten Seemann
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Deborah A Williamson
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia.,Antimicrobial Reference and Research Unit, Microbiological Diagnostic Unit Public Health Laboratory, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
| | - Benjamin P Howden
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia.,Antimicrobial Reference and Research Unit, Microbiological Diagnostic Unit Public Health Laboratory, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia.,Department of Infectious Diseases, Austin Health, Melbourne, VIC, Australia
| | - Glen P Carter
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia.,Antimicrobial Reference and Research Unit, Microbiological Diagnostic Unit Public Health Laboratory, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, Australia
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Karas JA, Carter GP, Howden BP, Turner AM, Paulin OKA, Swarbrick JD, Baker MA, Li J, Velkov T. Structure–Activity Relationships of Daptomycin Lipopeptides. J Med Chem 2020; 63:13266-13290. [DOI: 10.1021/acs.jmedchem.0c00780] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- John A. Karas
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Glen P. Carter
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Benjamin P. Howden
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Adrianna M. Turner
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
| | - Olivia K. A. Paulin
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - James D. Swarbrick
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Mark. A. Baker
- Priority Research Centre in Reproductive Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Jian Li
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Tony Velkov
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
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Tedizolid as Step-Down Therapy following Daptomycin versus Continuation of Daptomycin against Enterococci and Methicillin- and Vancomycin-Resistant Staphylococcus aureus in a Rat Endocarditis Model. Antimicrob Agents Chemother 2020; 64:AAC.02303-19. [PMID: 32122892 DOI: 10.1128/aac.02303-19] [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] [Received: 11/18/2019] [Accepted: 02/23/2020] [Indexed: 12/23/2022] Open
Abstract
Tedizolid (TZD) and daptomycin (DAP) were assessed in a rat endocarditis model against Enterococcus faecalis, Enterococcus faecium (resistant to vancomycin and ampicillin), and Staphylococcus aureus As a monotherapy, TZD for 5 days was not effective in a comparison with no-treatment controls, while DAP for 5 days was significantly effective against these bacteria. Step-down therapy (DAP for 3 days followed by TZD for 2 days) was as effective as DAP for 5 days and was comparable to 3 days of DAP plus ceftriaxone against all bacteria and to 3 days of DAP plus gentamicin against E. faecalis OG1RF.
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Jahanbakhsh S, Singh NB, Yim J, Kebriaei R, Smith JR, Lev K, Tran TT, Rose WE, Arias CA, Rybak MJ. Impact of Daptomycin Dose Exposure Alone or in Combination with β-Lactams or Rifampin against Vancomycin-Resistant Enterococci in an In Vitro Biofilm Model. Antimicrob Agents Chemother 2020; 64:e02074-19. [PMID: 32094136 PMCID: PMC7179592 DOI: 10.1128/aac.02074-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/19/2020] [Indexed: 12/22/2022] Open
Abstract
Enterococcus faecium strains are commonly resistant to vancomycin and β-lactams. In addition, E. faecium often causes biofilm-associated infections and these infections are difficult to treat. In this context, we investigated the activity of dosing regimens using daptomycin (DAP) (8, 10, 12, and 14 mg/kg of body weight/day) alone and in combination with ceftaroline (CPT), ampicillin (AMP), ertapenem (ERT), and rifampin (RIF) against 2 clinical strains of biofilm-producing vancomycin-resistant Enterococcus faecium (VREfm), namely, strains S447 and HOU503, in an in vitro biofilm model. HOU503 harbors common LiaS and LiaR substitutions, whereas S447 lacks mutations associated with the LiaFSR pathway. MIC results demonstrated that both strains were susceptible to DAP and resistant to CPT, AMP, ERT, and RIF. The 168-h pharmacokinetic/pharmacodynamic (PK/PD) CDC biofilm reactor models (simulating human antibiotic exposures) were used with titanium and polyurethane coupons to evaluate the efficacy of antibiotic combinations. DAP 12 and 14 achieved bactericidal activity against S447 but lacked such effect against HOU503. Addition of ERT and RIF enhanced DAP activity, allowing DAP 8 and 10 plus ERT or RIF to produce bactericidal activity against both strains at 168 h. While DAP 8 and 10 plus CPT improved killing, they did not reach bactericidal reduction against S447. Combination of AMP, CPT, ERT, or RIF resulted in enhanced and bactericidal activity for DAP against HOU503 at 168 h. Our data provide further support for the use of combinations of DAP with AMP, ERT, CPT, and RIF in infections caused by biofilm producing VREfm. Further research involving DAP combinations against biofilm-producing enterococci is warranted.
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Affiliation(s)
- Seyedehameneh Jahanbakhsh
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA
| | - Nivedita B Singh
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA
| | - Juwon Yim
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA
| | - Razieh Kebriaei
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA
| | - Jordan R Smith
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA
| | - Katherine Lev
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA
| | - T T Tran
- School of Pharmacy and Department of Medicine, University of Wisconsin-Madison, Wisconsin, USA
| | - Warren E Rose
- School of Pharmacy and Department of Medicine, University of Wisconsin-Madison, Wisconsin, USA
| | - Cesar A Arias
- Division of Infectious Diseases and Center for Antimicrobial Resistance and Microbial Genomics, UTHealth McGovern Medical School, Houston, Texas, USA
- Center for Infectious Diseases, UTHealth School of Public Health, Universidad El Bosque, Bogota, Colombia
- Molecular Genetics and Antimicrobial Resistance Unit-International Center for Microbial Genomics, Universidad El Bosque, Bogota, Colombia
| | - Michael J Rybak
- Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA
- School of Medicine, Wayne State University, Detroit, Michigan, USA
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Environment Shapes the Accessible Daptomycin Resistance Mechanisms in Enterococcus faecium. Antimicrob Agents Chemother 2019; 63:AAC.00790-19. [PMID: 31332078 DOI: 10.1128/aac.00790-19] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/16/2019] [Indexed: 02/07/2023] Open
Abstract
Daptomycin binds to bacterial cell membranes and disrupts essential cell envelope processes, leading to cell death. Bacteria respond to daptomycin by altering their cell envelopes to either decrease antibiotic binding to the membrane or by diverting binding away from septal targets. In Enterococcus faecalis, daptomycin resistance is typically coordinated by the three-component cell envelope stress response system, LiaFSR. Here, studying a clinical strain of multidrug-resistant Enterococcus faecium containing alleles associated with activation of the LiaFSR signaling pathway, we found that specific environments selected for different evolutionary trajectories, leading to high-level daptomycin resistance. Planktonic environments favored pathways that increased cell surface charge via yvcRS upregulation of dltABCD and mprF, causing a reduction in daptomycin binding. Alternatively, environments favoring complex structured communities, including biofilms, evolved both diversion and repulsion strategies via divIVA and oatA mutations, respectively. Both environments subsequently converged on cardiolipin synthase (cls) mutations, suggesting the importance of membrane modification across strategies. Our findings indicate that E. faecium can evolve diverse evolutionary trajectories to daptomycin resistance that are shaped by the environment to produce a combination of resistance strategies. The accessibility of multiple and different biochemical pathways simultaneously suggests that the outcome of daptomycin exposure results in a polymorphic population of resistant phenotypes, making E. faecium a recalcitrant nosocomial pathogen.
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