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Axell-House DB, Ashley PA, Egge SL, Tran TT, Pedroza C, Zhang M, Dinh AQ, Simar SR, Sahasrabhojane PV, Miller WR, Shelburne SA, Hanson BM, Arias CA. Clinical Features and Genomic Epidemiology of Bloodstream Infections due to Enterococcal Species Other Than Enterococcus faecalis or E. faecium in Patients With Cancer. Open Forum Infect Dis 2024; 11:ofae288. [PMID: 38835498 PMCID: PMC11148474 DOI: 10.1093/ofid/ofae288] [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: 02/02/2024] [Accepted: 05/15/2024] [Indexed: 06/06/2024] Open
Abstract
Background Non-Enterococcus faecium, non-E. faecalis (NFF) enterococci are a heterogeneous group of clinically pathogenic enterococci that include species with intrinsic low-level vancomycin resistance. Patients with cancer are at increased risk for bacteremia with NFF enterococci, but their clinical and molecular epidemiology have not been extensively described. Methods We conducted a retrospective review of all patients (n = 70) with NFF bacteremia from 2016 to 2022 at a major cancer center. The main outcomes assessed were 30-day mortality, microbiological failure (positive blood cultures for ≥4 days), and recurrence of bacteremia (positive blood culture <14 days after clearance). Whole-genome sequencing was performed on all available NFF (n = 65). Results Patients with hematological malignancies made up 56% of the cohort (77% had leukemia). The majority of solid malignancies (87%) were gastrointestinal in origin. The majority of infections (83%) originated from an intra-abdominal source. The most common NFF species were E. gallinarum (50%) and E. casseliflavus (30%). Most (61%) patients received combination therapy. Bacteremia recurred in 4.3% of patients, there was a 30-day mortality of 23%, and 4.3% had microbiological failure. E. gallinarum and E. casseliflavus isolates were genetically diverse with no spatiotemporal clustering to suggest a single strain. Frequencies of ampicillin resistance (4.3%) and daptomycin resistance (1.9%) were low. Patients with hematologic malignancy had infections with NFF enterococci that harbored more resistance genes than patients with solid malignancy (P = .005). Conclusions NFF bacteremia is caused by a heterogeneous population of isolates and is associated with significant mortality. Hematological malignancy is an important risk factor for infection with NFF resistant to multiple antibiotics.
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Affiliation(s)
- Dierdre B Axell-House
- Division of Infectious Diseases, Department of Medicine, Houston Methodist Hospital, Houston, Texas, USA
- Center for Infectious Diseases, Houston Methodist Research Institute, Houston, Texas, USA
- Department of Medicine, Weill Cornell Medical College, New York City, New York, USA
| | - Patrycja A Ashley
- Division of Infectious Diseases, Department of Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Stephanie L Egge
- Division of Infectious Diseases, Department of Medicine, Houston Methodist Hospital, Houston, Texas, USA
- Center for Infectious Diseases, Houston Methodist Research Institute, Houston, Texas, USA
| | - Truc T Tran
- Center for Infectious Diseases, Houston Methodist Research Institute, Houston, Texas, USA
| | - Claudia Pedroza
- Center for Clinical Research and Evidence-Based Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Meng Zhang
- Center for Clinical Research and Evidence-Based Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - An Q Dinh
- Center for Infectious Diseases, Houston Methodist Research Institute, Houston, Texas, USA
- Center for Infectious Diseases, School of Public Health, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Shelby R Simar
- Center for Infectious Diseases, School of Public Health, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Pranoti V Sahasrabhojane
- Department of Infectious Diseases, Infection Control, and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - William R Miller
- Division of Infectious Diseases, Department of Medicine, Houston Methodist Hospital, Houston, Texas, USA
- Center for Infectious Diseases, Houston Methodist Research Institute, Houston, Texas, USA
- Department of Medicine, Weill Cornell Medical College, New York City, New York, USA
| | - Samuel A Shelburne
- Department of Infectious Diseases, Infection Control, and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Blake M Hanson
- Center for Infectious Diseases, School of Public Health, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Cesar A Arias
- Division of Infectious Diseases, Department of Medicine, Houston Methodist Hospital, Houston, Texas, USA
- Center for Infectious Diseases, Houston Methodist Research Institute, Houston, Texas, USA
- Department of Medicine, Weill Cornell Medical College, New York City, New York, USA
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Bender JK, Fleige C, Funk F, Moretó-Castellsagué C, Fischer MA, Werner G. Linezolid Resistance Genes and Mutations among Linezolid-Susceptible Enterococcus spp.-A Loose Cannon? Antibiotics (Basel) 2024; 13:101. [PMID: 38275330 PMCID: PMC10812394 DOI: 10.3390/antibiotics13010101] [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: 11/30/2023] [Revised: 01/16/2024] [Accepted: 01/17/2024] [Indexed: 01/27/2024] Open
Abstract
The National Reference Centre for Enterococci receives an increasing number of linezolid-resistant Enterococcus isolates. Linezolid (LIN) resistance is mediated by G2576T 23S rDNA gene mutations and/or acquisition of resistance genes (cfr, optrA, poxtA). There are anecdotal reports that those resistance traits may be present in phenotypically linezolid-susceptible isolates. We aimed to determine the prevalence of LIN resistance genes and mutations in enterococci with a LIN MIC of 4 mg/L in broth microdilution (EUCAST = susceptible) isolated from German hospital patients 2019-2021. LIN MICs were additionally determined by ETEST® and VITEK2. Selected strains were subjected to LIN selective pressure and growth was monitored with increasing antibiotic concentrations. We received 195 isolates (LIN MIC = 4 mg/L). In total, 78/195 (40%) isolates contained either a putative resistance gene, the G2576T mutation, or a combination thereof. Very major error was high for broth microdilution. The ability to predict phenotypic resistance from genotypic profile was highest for G2576T-mediated resistance. Selection experiments revealed that, in particular, E. faecium isolates with resistance gene mutations or poxtA rapidly adapt to MICs above the clinical breakpoint. In conclusion, LIN resistance genes and mutations can be observed in phenotypically linezolid-susceptible enterococci. Those isolates may rapidly develop resistance under LIN selective pressure potentially leading to treatment failure.
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Affiliation(s)
- Jennifer K. Bender
- Nosocomial Pathogens and Antibiotic Resistances Unit, Department of Infectious Diseases, Robert Koch Institute, 38855 Wernigerode, Germany (F.F.); (C.M.-C.); (M.A.F.); (G.W.)
| | - Carola Fleige
- Nosocomial Pathogens and Antibiotic Resistances Unit, Department of Infectious Diseases, Robert Koch Institute, 38855 Wernigerode, Germany (F.F.); (C.M.-C.); (M.A.F.); (G.W.)
| | - Finn Funk
- Nosocomial Pathogens and Antibiotic Resistances Unit, Department of Infectious Diseases, Robert Koch Institute, 38855 Wernigerode, Germany (F.F.); (C.M.-C.); (M.A.F.); (G.W.)
| | - Clara Moretó-Castellsagué
- Nosocomial Pathogens and Antibiotic Resistances Unit, Department of Infectious Diseases, Robert Koch Institute, 38855 Wernigerode, Germany (F.F.); (C.M.-C.); (M.A.F.); (G.W.)
- Department of Microbiology and Parasitology, University Hospital of Bellvitge, 08907 Barcelona, Spain
| | - Martin A. Fischer
- Nosocomial Pathogens and Antibiotic Resistances Unit, Department of Infectious Diseases, Robert Koch Institute, 38855 Wernigerode, Germany (F.F.); (C.M.-C.); (M.A.F.); (G.W.)
| | - Guido Werner
- Nosocomial Pathogens and Antibiotic Resistances Unit, Department of Infectious Diseases, Robert Koch Institute, 38855 Wernigerode, Germany (F.F.); (C.M.-C.); (M.A.F.); (G.W.)
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Nandivarmane SB, Manoharan M, Sugumar M, Sistla S. Evaluation of different linezolid susceptibility testing methods and detection of linezolid resistance gene (cfr) in staphylococcal isolates. Indian J Med Microbiol 2024; 47:100516. [PMID: 38000621 DOI: 10.1016/j.ijmmb.2023.100516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 11/13/2023] [Accepted: 11/20/2023] [Indexed: 11/26/2023]
Abstract
Linezolid is an effective oxazolidinone antibiotic against multi resistant Gram-positive organisms. Linezolid resistance is an emerging problem and some controversy exists about the reliability of different phenotypic methods of linezolid susceptibility testing. Fifty isolates each of methicillin resistant S. aureus (MRSA) and Staphylococcus haemolyticus were tested for linezolid susceptibility using Kirby-Bauer disc diffusion, E-test, automated system VITEK2, Broth micro-dilution (reference method) and PCR for the cfr gene. Six resistant isolates were identified, three each in MRSA and S. haemolyticus, all carrying the cfr gene. E-test and VITEK2 were found to be more accurate than disc diffusion test.
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Affiliation(s)
- Sudarsan Bagavane Nandivarmane
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India.
| | - Meerabai Manoharan
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India.
| | - Madhan Sugumar
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India.
| | - Sujatha Sistla
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India.
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Migliorisi G, Calvo M, Collura A, Di Bernardo F, Perez M, Scalia G, Stefani S. The Rapid Phenotypic Susceptibility Testing in Real-Life Experience: How the MIC Values Impact on Sepsis Fast Diagnostic Workflow. Diagnostics (Basel) 2023; 14:56. [PMID: 38201365 PMCID: PMC10802849 DOI: 10.3390/diagnostics14010056] [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: 11/18/2023] [Revised: 12/22/2023] [Accepted: 12/25/2023] [Indexed: 01/12/2024] Open
Abstract
The MIC value definition faithfully reflects antimicrobial sensitivity, profoundly impacting the infection's clinical outcome. Our study aimed to evaluate the Accelerate PhenoTM System in defining the importance of fast phenotypic susceptibility data. A number of 270 monomicrobial samples simultaneously underwent standard procedures and fast protocols after a contemporary Gram stain. Finally, we provided Turn-around Time (TAT) and statistical evaluations. The fast technology required a medium value of 7 h to complete ID and AST profiles. Although there were some spectrum limitations, it revealed an optimal success rate in microbial identification directly from positive blood cultures. The Gram-negative AST reached a 98.9% agreement between the Accelerate Pheno™ System and the standard method. In addition, the Gram-positive AST gathered a 98.7% agreement comparing the same systems. The chance to rapidly provide precise MIC values is one of the last frontiers in clinical microbiology, especially in high-prevalence antimicrobial resistance areas.
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Affiliation(s)
- Giuseppe Migliorisi
- U.O.C. Laboratory Analysis A.O.U. “Policlinico—San Marco”, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (S.S.)
| | - Maddalena Calvo
- U.O.C. Laboratory Analysis A.O.U. “Policlinico—San Marco”, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (S.S.)
| | - Antonina Collura
- U.O.C. Clinical Microbiology, “Civico-Di Cristina-Benfratelli” Hospital, Piazza Nicola Leotta 4, 90127 Palermo, Italy
| | - Francesca Di Bernardo
- U.O.C. Clinical Microbiology, “Civico-Di Cristina-Benfratelli” Hospital, Piazza Nicola Leotta 4, 90127 Palermo, Italy
| | - Marianna Perez
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy
| | - Guido Scalia
- U.O.C. Laboratory Analysis A.O.U. “Policlinico—San Marco”, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (S.S.)
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy
| | - Stefania Stefani
- U.O.C. Laboratory Analysis A.O.U. “Policlinico—San Marco”, Via Santa Sofia 78, 95123 Catania, Italy; (M.C.); (S.S.)
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123 Catania, Italy
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Fernández-Cuenca F, López-Hernández I, Cercenado E, Conejo MC, Tormo N, Gimeno C, Pascual A. Reporting antimicrobial susceptibilities and phenotypes of resistance to vancomycin in vancomycin-resistant Enterococcus spp. clinical isolates: A nationwide proficiency study. ENFERMEDADES INFECCIOSAS Y MICROBIOLOGIA CLINICA (ENGLISH ED.) 2023:S2529-993X(22)00310-0. [PMID: 36610833 DOI: 10.1016/j.eimce.2021.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 11/19/2021] [Indexed: 01/07/2023]
Abstract
INTRODUCTION The ability of Spanish microbiology laboratories to (a) determine antimicrobial susceptibility (AS), and (b) correctly detect the vancomycin resistance (VR) phenotype in vancomycin-resistant Enterococcus spp. (VRE) was evaluated. METHODS Three VRE isolates representing the VanA (E. faecium), VanB (E. faecium) and VanC (E. gallinarum) VR phenotypes were sent to 52 laboratories, which were asked for: (a) AS method used; (b) MICs of ampicillin, imipenem, vancomycin, teicoplanin, linezolid, daptomycin, ciprofloxacin, levofloxacin and quinupristin-dalfopristin, and high-level resistance to gentamicin and streptomycin; (c) VR phenotype. RESULTS (a) The most frequently used system was MicroScan; (b) according to the system, the highest percentage of discrepant MICs was found with gradient strips (21.3%). By antimicrobial, the highest rates of discrepant MICs ranged 16.7% (imipenem) to 0.7% (linezolid). No discrepant MICs were obtained with daptomycin or levofloxacin. Mayor errors (MEs) occurred with linezolid (1.1%/EUCAST) and ciprofloxacin (5.0%/CLSI), and very major errors (VMEs) with vancomycin (27.1%/EUCAST and 33.3%/CLSI) and teicoplanin (5.7%/EUCAST and 2.3%/CLSI). For linezolid, ciprofloxacin, and vancomycin, discrepant MICs were responsible for these errors, while for teicoplanin, errors were due to a misassignment of the clinical category. An unacceptable high percentage of VMEs was obtained using gradient strips (14.8%), especially with vancomycin, teicoplanin and daptomycin; (c) 86.4% of the centers identified VanA and VanB phenotypes correctly, and 95.0% the VanC phenotype. CONCLUSION Most Spanish microbiology laboratories can reliably determine AS in VRE, but there is a significant percentage of inadequate interpretations (warning of false susceptibility) for teicoplanin in isolates with the VanB phenotype.
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Affiliation(s)
- Felipe Fernández-Cuenca
- Unidad Clínica de Enfermedades Infecciosas y Microbiología Clínica, Hospital Universitario Virgen Macarena, Sevilla, Spain; Instituto de Biomedicina de Sevilla (IBIs), Hospital Universitario Virgen Macarena/CSIC/Universidad de Sevilla, Sevilla, Spain; Spanish Network for the Research in Infectious Diseases (REIPI RD16/0016), Instituto de Salud Carlos III, Madrid, Spain.
| | - Inmaculada López-Hernández
- Unidad Clínica de Enfermedades Infecciosas y Microbiología Clínica, Hospital Universitario Virgen Macarena, Sevilla, Spain; Instituto de Biomedicina de Sevilla (IBIs), Hospital Universitario Virgen Macarena/CSIC/Universidad de Sevilla, Sevilla, Spain; Spanish Network for the Research in Infectious Diseases (REIPI RD16/0016), Instituto de Salud Carlos III, Madrid, Spain
| | - Emilia Cercenado
- Servicio de Microbiología y Enfermedades Infecciosas. Hospital General Universitario Gregorio Marañón, Madrid, Spain; Departamento de Medicina, Facultad de Medicina, Universidad Complutense, Madrid, Spain; CIBERES, Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, CB06/06/0058, Madrid, Spain
| | | | - Nuria Tormo
- Servicio de Microbiología, Hospital General de Valencia, Valencia, Spain; Quality Control Programme (CCS), Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC), Valencia, Spain
| | - Concepción Gimeno
- Servicio de Microbiología, Hospital General de Valencia, Valencia, Spain; Quality Control Programme (CCS), Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC), Valencia, Spain
| | - Alvaro Pascual
- Unidad Clínica de Enfermedades Infecciosas y Microbiología Clínica, Hospital Universitario Virgen Macarena, Sevilla, Spain; Instituto de Biomedicina de Sevilla (IBIs), Hospital Universitario Virgen Macarena/CSIC/Universidad de Sevilla, Sevilla, Spain; Spanish Network for the Research in Infectious Diseases (REIPI RD16/0016), Instituto de Salud Carlos III, Madrid, Spain; Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain
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Saini V, Goyal N, Singh NP, Goswami M. Evaluation of errors during susceptibility reporting of glycopeptide antibiotics for enterococcal isolates on sole basis of widely used disk diffusion test. HEALTHCARE IN LOW-RESOURCE SETTINGS 2022. [DOI: 10.4081/hls.2022.10806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In resource limited settings, very often susceptibility reports glycopeptide antibiotics are released only on the basis of disk diffusion test. Determination of MIC by either E-strips or microbroth dilution tests can be of paramount importance in checking the errors that may have incurred with the singular use of disk diffusion tests. Distribution of errors in Vancomycin and Teicoplanin susceptibility reporting by disk diffusion test was evaluated in comparison with MIC determination with reference method of E-strip. A total of 40 isolates of Enterococcus species were obtained during the study period. In vancomycin susceptibility reporting, very major errors, major errors and minor errors were observed in 33.3%, 5.4% and 5% instances respectively. For teicoplanin, major errors were observed in 5.3% of instances. E test can be used in conjunction with disk diffusion where resources are limited. We have observed that by using a combination of both disk diffusion and MIC determination by E-strip methods for glycopeptide antibiotics, a majority of reporting errors can be addressed.
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Abstract
Enterococci are major, recalcitrant nosocomial pathogens with a wide repertoire of intrinsic and acquired resistance determinants and the potential of developing resistance to all clinically available antimicrobials. As such, multidrug-resistant enterococci are considered a serious public health threat. Due to limited treatment options and rapid emergence of resistance to all novel agents, the clinical microbiology laboratory plays a critical role in deploying accurate, reproducible, and feasible antimicrobial susceptibility testing methods to guide appropriate treatment of patients with deep-seated enterococcal infections. In this review, we provide an overview of the advantages and disadvantages of existing manual and automated methods that test susceptibility of Enterococcus faecium and Enterococcus faecalis to β-lactams, aminoglycosides, vancomycin, lipoglycopeptides, oxazolidinones, novel tetracycline-derivatives, and daptomycin. We also identify unique problems and gaps with the performance and clinical utility of antimicrobial susceptibility testing for enterococci, provide recommendations for clinical laboratories to circumvent select problems, and address potential future innovations that can bridge major gaps in susceptibility testing.
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Machine Learning for Antimicrobial Resistance Prediction: Current Practice, Limitations, and Clinical Perspective. Clin Microbiol Rev 2022; 35:e0017921. [PMID: 35612324 DOI: 10.1128/cmr.00179-21] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Antimicrobial resistance (AMR) is a global health crisis that poses a great threat to modern medicine. Effective prevention strategies are urgently required to slow the emergence and further dissemination of AMR. Given the availability of data sets encompassing hundreds or thousands of pathogen genomes, machine learning (ML) is increasingly being used to predict resistance to different antibiotics in pathogens based on gene content and genome composition. A key objective of this work is to advocate for the incorporation of ML into front-line settings but also highlight the further refinements that are necessary to safely and confidently incorporate these methods. The question of what to predict is not trivial given the existence of different quantitative and qualitative laboratory measures of AMR. ML models typically treat genes as independent predictors, with no consideration of structural and functional linkages; they also may not be accurate when new mutational variants of known AMR genes emerge. Finally, to have the technology trusted by end users in public health settings, ML models need to be transparent and explainable to ensure that the basis for prediction is clear. We strongly advocate that the next set of AMR-ML studies should focus on the refinement of these limitations to be able to bridge the gap to diagnostic implementation.
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Reporting antimicrobial susceptibilities and phenotypes of resistance to vancomycin in vancomycin-resistant Enterococcus spp. clinical isolates: A nationwide proficiency study. Enferm Infecc Microbiol Clin 2022. [DOI: 10.1016/j.eimc.2021.11.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Comparative Performances of Vitek-2, Disk Diffusion, and Broth Microdilution for Antimicrobial Susceptibility Testing of Canine Staphylococcus pseudintermedius. J Clin Microbiol 2021; 59:e0034921. [PMID: 34132581 DOI: 10.1128/jcm.00349-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Staphylococcus pseudintermedius is the primary cause of canine cutaneous infections and is sporadically isolated as a pathogen from humans. Rapidly emerging antibiotic-resistant strains are creating serious health concerns so that accurate and timely antimicrobial susceptibility testing (AST) is crucial for patient care. Here, the performances of the AST methods Vitek-2, disk diffusion (DD) and broth microdilution (BMD) were compared for the determination of susceptibility of 79 S. pseudintermedius isolates from canine cutaneous infections and one from human pyoderma to oxacillin (OXA), amoxicillin/clavulanate (AMC), cephalothin (CEF), gentamicin (GEN), enrofloxacin (ENR), doxycycline (DOX), clindamycin (CLI), inducible clindamycin resistance (ICR), mupirocin (MUP), and trimethoprim-sulfamethoxazole (SXT). Overall, the agreement of DD and Vitek-2 using the veterinary AST-GP80 card with reference BMD was ≥90%, suggesting reliable AST performances. While DD generated mainly minor errors and one major error for OXA, Vitek-2 produced one very major error for GEN, and it failed in identifying one ICR-positive isolate. Moreover, five bacteria were diagnosed as ICR-positive by Vitek-2, but they showed a noninduction resistance phenotype with manual methods. All S. pseudintermedius isolates were interpreted as susceptible or intermediately susceptible to DOX using CLSI breakpoints for human staphylococci that match the DOX concentration range included in AST-GP80. However, this could lead to inappropriate antimicrobial prescription for S. pseudintermedius infections in companion animals. Considering the clinical and epidemiological importance of S. pseudintermedius, we encourage updating action by the system manufacturer to address AST for this bacterium.
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Dejoies L, Boukthir S, Péan de Ponfilly G, Le Guen R, Zouari A, Potrel S, Collet A, Auger G, Jacquier H, Fihman V, Dortet L, Cattoir V. Performance of commercial methods for linezolid susceptibility testing of Enterococcus faecium and Enterococcus faecalis. J Antimicrob Chemother 2021; 75:2587-2593. [PMID: 32449911 DOI: 10.1093/jac/dkaa180] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/03/2020] [Accepted: 04/09/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Linezolid-resistant enterococci (LRE) causing infections that are challenging to treat are rising, highlighting the need for reliable screening of LRE clinical isolates. OBJECTIVES To evaluate the ability of the broth microdilution (BMD) method for LRE detection and to assess the performance of seven commercially available techniques for linezolid susceptibility testing. METHODS A collection of 100 clinical isolates (80 Enterococcus faecium and 20 Enterococcus faecalis), including 20 optrA-positive isolates, 17 poxtA-positive isolates and 1 optrA/poxtA-positive E. faecium isolate, were studied. MICs were determined after 18 h [Day 1 (D1)] and 42 h [Day 2 (D2)] of incubation and interpreted following EUCAST and CLSI guidelines, which currently provide different interpretative breakpoints. Performance of commercial techniques was compared with BMD results. RESULTS MIC50/D1 and MIC50/D2 were both 8 mg/L, while MIC90/D1 and MIC90/D2 were 16 and 32 mg/L, respectively. MICD1 values for poxtA-positive isolates were lower than those for optrA-positive isolates. Proportions of susceptible isolates at D1 and D2 were 48% and 41%, respectively, according to EUCAST breakpoints and 35% and 13%, respectively, according to CLSI criteria (the proportions of isolates categorized as intermediate following CLSI recommendations were 13% and 28% at D1 and D2, respectively). Percentage susceptibility assessed by the commercially available techniques was always higher. The four commercial methods allowing MIC determination provided an overall essential agreement of ≥90% at D1. Categorical agreement and error rates were generally improved at D2. CONCLUSIONS Non-automated methods (Sensititre and UMIC) and, to a lesser extent, gradient strip Etest appear to show an acceptable correlation with the BMD reference method for the detection of isolates with low MICs of linezolid after prolonged incubation.
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Affiliation(s)
- Loren Dejoies
- CHU de Rennes, Service de Bactériologie et Hygiène Hospitalière, Rennes, France.,U1230 'ARN régulateurs Bactériens et Médecine', Université Rennes 1, Rennes, France
| | - Sarrah Boukthir
- CHU de Rennes, Service de Bactériologie et Hygiène Hospitalière, Rennes, France
| | | | - Ronan Le Guen
- Hôpitaux Universitaires Henri Mondor, Unité de Bactériologie-Hygiène, Créteil, France
| | - Asma Zouari
- CHU de Rennes, Service de Bactériologie et Hygiène Hospitalière, Rennes, France.,CNR de la Résistance aux Antibiotiques (laboratoire associé 'Entérocoques'), Rennes, France
| | - Sophie Potrel
- CHU de Rennes, Service de Bactériologie et Hygiène Hospitalière, Rennes, France.,CNR de la Résistance aux Antibiotiques (laboratoire associé 'Entérocoques'), Rennes, France
| | - Anaïs Collet
- CHU de Rennes, Service de Bactériologie et Hygiène Hospitalière, Rennes, France.,CNR de la Résistance aux Antibiotiques (laboratoire associé 'Entérocoques'), Rennes, France
| | - Gabriel Auger
- CHU de Rennes, Service de Bactériologie et Hygiène Hospitalière, Rennes, France.,CNR de la Résistance aux Antibiotiques (laboratoire associé 'Entérocoques'), Rennes, France
| | - Hervé Jacquier
- Hôpital Lariboisière, Service de Bactériologie-Virologie, Paris, France
| | - Vincent Fihman
- Hôpitaux Universitaires Henri Mondor, Unité de Bactériologie-Hygiène, Créteil, France.,EA 7380 Dynamyc, EnvA, UPEC, Paris-Est University, Créteil, France
| | - Laurent Dortet
- CHU de Bicêtre, service de Bactériologie-Hygiène, Le Kremlin-Bicêtre, France
| | - Vincent Cattoir
- CHU de Rennes, Service de Bactériologie et Hygiène Hospitalière, Rennes, France.,U1230 'ARN régulateurs Bactériens et Médecine', Université Rennes 1, Rennes, France.,CNR de la Résistance aux Antibiotiques (laboratoire associé 'Entérocoques'), Rennes, France
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Mobile Oxazolidinone Resistance Genes in Gram-Positive and Gram-Negative Bacteria. Clin Microbiol Rev 2021; 34:e0018820. [PMID: 34076490 DOI: 10.1128/cmr.00188-20] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Seven mobile oxazolidinone resistance genes, including cfr, cfr(B), cfr(C), cfr(D), cfr(E), optrA, and poxtA, have been identified to date. The cfr genes code for 23S rRNA methylases, which confer a multiresistance phenotype that includes resistance to phenicols, lincosamides, oxazolidinones, pleuromutilins, and streptogramin A compounds. The optrA and poxtA genes code for ABC-F proteins that protect the bacterial ribosomes from the inhibitory effects of oxazolidinones. The optrA gene confers resistance to oxazolidinones and phenicols, while the poxtA gene confers elevated MICs or resistance to oxazolidinones, phenicols, and tetracycline. These oxazolidinone resistance genes are most frequently found on plasmids, but they are also located on transposons, integrative and conjugative elements (ICEs), genomic islands, and prophages. In these mobile genetic elements (MGEs), insertion sequences (IS) most often flanked the cfr, optrA, and poxtA genes and were able to generate translocatable units (TUs) that comprise the oxazolidinone resistance genes and occasionally also other genes. MGEs and TUs play an important role in the dissemination of oxazolidinone resistance genes across strain, species, and genus boundaries. Most frequently, these MGEs also harbor genes that mediate resistance not only to antimicrobial agents of other classes, but also to metals and biocides. Direct selection pressure by the use of antimicrobial agents to which the oxazolidinone resistance genes confer resistance, but also indirect selection pressure by the use of antimicrobial agents, metals, or biocides (the respective resistance genes against which are colocated on cfr-, optrA-, or poxtA-carrying MGEs) may play a role in the coselection and persistence of oxazolidinone resistance genes.
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Elghaieb H, Freitas AR, Abbassi MS, Novais C, Zouari M, Hassen A, Peixe L. Dispersal of linezolid-resistant enterococci carrying poxtA or optrA in retail meat and food-producing animals from Tunisia. J Antimicrob Chemother 2020; 74:2865-2869. [PMID: 31243458 DOI: 10.1093/jac/dkz263] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 05/02/2019] [Accepted: 05/23/2019] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVES The epidemiology of Enterococcus resistant to priority antibiotics including linezolid has mainly been investigated in developed countries and especially in hospitals. We aimed to evaluate the contribution of different non-human reservoirs for the burden of MDR enterococci in Tunisia, where scarce data are available. METHODS Samples (n = 287) were collected from urban wastewater (n = 57), retail meat (n = 29; poultry/bovine/ovine), milk (n = 89; bovine/ovine), farm animal faeces (n = 80; poultry/bovine/ovine) and pets (n = 32; rabbit/dogs/cats/birds) in different Tunisian regions (2014-17). They were plated onto Slanetz-Bartley agar after pre-enrichment without antibiotics. Standard methods were used for bacterial identification and characterization of antibiotic resistance and virulence genes (PCR), antibiotic susceptibility testing (disc diffusion/broth microdilution; EUCAST/CLSI) and clonality (SmaI-PFGE/MLST). RESULTS All samples carried Enterococcus (n = 377 isolates) resistant to antibiotics considered to be critical or highly important by WHO. Even without antibiotic selection, 38% of Enterococcus faecalis (Efs) and 22% of Enterococcus faecium (Efm) were identified as MDR. Linezolid-resistant isolates (5%; MIC = 8 mg/L) comprised six poxtA-carrying Efm (cow milk), seven optrA-carrying Efs (chicken faeces/meat) and five Efm lacking cfr/optrA/poxtA (poultry/bovine/ovine/wastewater). Clinically relevant Efm clones (clade A1) were identified in animal/meat sources. Ampicillin resistance (1%) was confined to ST18/ST78-like MDR Efm clones from bovine meat/milk samples carrying relevant virulence markers (e.g. ptsD/IS16). CONCLUSIONS This study provides evidence of the contribution of livestock and foodstuffs to the dispersal of acquired linezolid resistance genes including poxtA and optrA. We report the first poxtA-carrying Efm in Tunisia, and for the first time in bovine samples, stressing the urgent need for alternative measures to counteract the spread of linezolid-resistant enterococci globally.
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Affiliation(s)
- Houyem Elghaieb
- Université de Tunis El Manar, Institut de la Recherche Vétérinaire de Tunisie, Tunis, Tunisia
| | - Ana R Freitas
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Mohamed Salah Abbassi
- Université de Tunis El Manar, Institut de la Recherche Vétérinaire de Tunisie, Tunis, Tunisia
| | - Carla Novais
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | | | - Abdennaceur Hassen
- Laboratoire de Traitement des Eaux Usées, Centre des Recherches et des Technologies des Eaux (CERTE), Technopole Borj Cédria, Hammam-Lif, Tunisia
| | - Luísa Peixe
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
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Yoo IY, Kang OK, Shim HJ, Huh HJ, Lee NY. Linezolid Resistance in Methicillin-Resistant Staphylococcus aureus in Korea: High Rate of False Resistance to Linezolid by the VITEK 2 System. Ann Lab Med 2020; 40:57-62. [PMID: 31432640 PMCID: PMC6713661 DOI: 10.3343/alm.2020.40.1.57] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 06/17/2019] [Accepted: 07/26/2019] [Indexed: 11/21/2022] Open
Abstract
As various linezolid resistance mechanisms have been identified in methicillin-resistant Staphylococcus aureus (MRSA), we investigated the molecular characteristics of MRSA with elevated linezolid minimum inhibitory concentrations (MICs), using the VITEK 2 system (bioMérieux, Marcy-l'Étoile, France). Twenty-seven MRSA isolates from 14 patients exhibiting linezolid MICs ≥8 µg/mL were examined by broth microdilution (BMD) test as well as by sequencing for mutations in the 23S rRNA gene or ribosomal proteins (L3, L4, and L22) and the presence of the optrA, cfr, and cfr(B) genes. Of the 27 isolates, four (14.8%) from one patient were confirmed as linezolid resistant by BMD and harbored a 23S rRNA T2500A mutation. The remaining 23 were confirmed as linezolid susceptible, indicating that the linezolid-resistant results were major errors generated by VITEK 2. The most commonly detected mutation (19/27, 70.4%), L3 Gly152Asp, was detected in only linezolid-susceptible isolates. No isolates contained optrA, cfr, or cfr(B) or any L4 or L22 protein alterations. Our results show that the 23S rRNA T2500A mutation was mainly associated with linezolid resistance, while the L3 Gly152Asp mutation was not related to linezolid resistance. A confirmatory test is recommended for VITEK 2 linezolid-resistant results owing to the high probability of false resistant results.
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Affiliation(s)
- In Young Yoo
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - On Kyun Kang
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hyang Jin Shim
- Center for Clinical Medicine, Samsung Biomedical Research Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hee Jae Huh
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
| | - Nam Yong Lee
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
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Palavecino EL. Clinical, Epidemiologic, and Laboratory Aspects of Methicillin-Resistant Staphylococcus aureus Infections. Methods Mol Biol 2020; 2069:1-28. [PMID: 31523762 DOI: 10.1007/978-1-4939-9849-4_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Oxacillin-resistant Staphylococcus aureus (abbreviated MRSA for historical reasons) is a major pathogen responsible for both hospital- and community-onset disease. Resistance to oxacillin in most clinical isolates of S. aureus is mediated by PBP2a, a penicillin-binding protein with low affinity to beta-lactams, encoded primarily by the mecA gene. Rapid and accurate methods of susceptibility testing of S. aureus isolates to identify MRSA infections are important tools to limit the spread of this organism. This review focuses on the clinical significance of MRSA infections and new approaches for the laboratory diagnosis and epidemiologic typing of MRSA strains.
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Affiliation(s)
- Elizabeth L Palavecino
- Department of Pathology, Clinical Microbiology Laboratory, Wake Forest School of Medicine, Winston-Salem, NC, USA.
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Azhar A, Rasool S, Haque A, Shan S, Saeed M, Ehsan B, Haque A. Detection of high levels of resistance to linezolid and vancomycin in Staphylococcus aureus. J Med Microbiol 2017; 66:1328-1331. [PMID: 28857738 DOI: 10.1099/jmm.0.000566] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Both methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) are rapidly overcoming the current array of drugs. One hundred and fifty isolates from a hospital were studied for resistance towards linezolid and vancomycin. Fifty-four (36.0 %) isolates were MRSA. Both MRSA and MSSA showed high resistance towards linezolid when using the disc diffusion method, with the figures being 48.1 and 29.2 %, respectively. The figures for the E-test were 46.3 and 27.0 %, respectively. The vancomycin resistance was remarkable in MRSA (14.8 %), but relatively low in MSSA (3.1 %). The E-test results were 13.0 and 4.16 %, respectively. The cfr gene was detected in 78 % of linezolid-resistant isolates and the vanA operon was detected in 74 % of vancomycin-resistant isolates. This level of resistance against linezolid and vancomycin is unprecedented. These results are alarming and highlight the threat of non-treatable S. aureus strains.
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Affiliation(s)
- Aysha Azhar
- Postgraduate Research Laboratory, The University of Faisalabad, Faisalabad, Pakistan
| | - Samreen Rasool
- Postgraduate Research Laboratory, The University of Faisalabad, Faisalabad, Pakistan
| | - Asma Haque
- Department of Bioinformatics and Biotechnology, GC University, Faisalabad, Pakistan
| | - Sidra Shan
- Postgraduate Research Laboratory, The University of Faisalabad, Faisalabad, Pakistan
| | - Muhammad Saeed
- Postgraduate Research Laboratory, The University of Faisalabad, Faisalabad, Pakistan
| | - Beenish Ehsan
- Department of Bioinformatics and Biotechnology, GC University, Faisalabad, Pakistan
| | - Abdul Haque
- Postgraduate Research Laboratory, The University of Faisalabad, Faisalabad, Pakistan
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Rojas LJ, Salim M, Cober E, Richter SS, Perez F, Salata RA, Kalayjian RC, Watkins RR, Marshall S, Rudin SD, Domitrovic TN, Hujer AM, Hujer KM, Doi Y, Kaye KS, Evans S, Fowler VG, Bonomo RA, van Duin D. Colistin Resistance in Carbapenem-Resistant Klebsiella pneumoniae: Laboratory Detection and Impact on Mortality. Clin Infect Dis 2017; 64:711-718. [PMID: 27940944 PMCID: PMC5850634 DOI: 10.1093/cid/ciw805] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 11/11/2017] [Accepted: 11/29/2017] [Indexed: 11/12/2022] Open
Abstract
Background Polymyxins including colistin are an important "last-line" treatment for infections caused by carbapenem-resistant Klebsiella pneumoniae (CRKp). Increasing use of colistin has led to resistance to this cationic antimicrobial peptide. Methods A cohort nested within the Consortium on Resistance against Carbapenems in Klebsiella pneumoniae (CRACKLE) was constructed of patients with infection, or colonization with CRKp isolates tested for colistin susceptibility during the study period of December, 2011 to October, 2014. Reference colistin resistance determination as performed by broth macrodilution was compared to results from clinical microbiology laboratories (Etest) and to polymyxin resistance testing. Each patient was included once, at the time of their first colistin-tested CRKp positive culture. Time to 30-day in-hospital all-cause mortality was evaluated by Kaplan-Meier curves and Cox proportional hazard modeling. Results In 246 patients with CRKp, 13% possessed ColR CRKp. ColR was underestimated by Etest (very major error rate = 35%, major error rate = 0.4%). A variety of rep-PCR strain types were encountered in both the ColS and the ColR groups. Carbapenem resistance was mediated primarily by blaKPC-2 (46%) and blaKPC-3 (50%). ColR was associated with increased hazard for in-hospital mortality (aHR 3.48; 95% confidence interval, 1.73-6.57; P < .001). The plasmid-associated ColR genes, mcr-1 and mcr-2 were not detected in any of the ColR CRKp. Conclusions In this cohort, 13% of patients with CRKp presented with ColR CRKp. The apparent polyclonal nature of the isolates suggests de novo emergence of ColR in this cohort as the primary factor driving ColR. Importantly, mortality was increased in patients with ColR isolates.
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Affiliation(s)
- Laura J Rojas
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Madiha Salim
- Division of Infectious Diseases, Detroit Medical Center, Wayne State University, Michigan, USA
| | - Eric Cober
- Department of Infectious Diseases, Cleveland Clinic, Cleveland, Ohio, USA
| | - Sandra S Richter
- Department of Laboratory Medicine, Cleveland Clinic, Cleveland, OH, USA
| | - Federico Perez
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Robert A Salata
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Robert C Kalayjian
- Department of Medicine, MetroHealth Medical Center, Cleveland, Ohio, USA
| | - Richard R Watkins
- Department of Internal Medicine, Northeast Ohio Medical University, Rootstown, OH , USA
- Division of Infectious Diseases, Cleveland Clinic Akron General Medical Center , Akron , OH , USA
| | - Steve Marshall
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Susan D Rudin
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - T Nicholas Domitrovic
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Andrea M Hujer
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Kristine M Hujer
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Yohei Doi
- Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pennsylvania, USA
| | - Keith S Kaye
- Division of Infectious Diseases, Detroit Medical Center, Wayne State University, Michigan, USA
| | - Scott Evans
- Department of Biostatistics and the Center for Biostatistics in AIDS Research, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Vance G Fowler
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
- Duke Clinical Research Institute, Duke University, Durham, North Carolina, USA
| | - Robert A Bonomo
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Departments of Pharmacology, Molecular Biology and Microbiology, Biochemistry, and Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - David van Duin
- Division of Infectious Diseases, University of North Carolina, Chapel Hill, USA
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Development of advanced biantibiotic loaded bone cement spacers for arthroplasty associated infections. Int J Pharm 2017; 522:11-20. [PMID: 28257884 DOI: 10.1016/j.ijpharm.2017.02.066] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 02/22/2017] [Accepted: 02/26/2017] [Indexed: 11/22/2022]
Abstract
The incidence increase of infections in patients with hip or knee implants with resistant pathogens (mainly some S. coagulase-negative and gram positive bacteria) demands advanced antibiotic loaded formulations. In this paper, we report the design of new biantibiotic acrylic bone cements for in situ delivery. They include a last generation antibiotic (daptomycin or linezolid) in combination with vancomycin and are performed based on a novel modification of the Palacos R® acrylic bone cement, which is based on two components, a liquid (methyl methacrylate) and a solid (polymeric phase). Hence, the solid component of the experimental formulations include 45wt% of microparticles of poly(D,L-lactic-co-glycolic) acid, 55wt% of poly(methyl methacrylate) beads and supplements (10wt-% each) of antibiotics. These formulations provide a selective and excellent control of the local release of antibiotics during a long time period (up to 2 months), avoiding systemic dissemination. The antimicrobial activity of the advanced spacers tested against S. aureus shows that single doses would be enough for the control of the infection. In vitro biocompatibility of cements on human osteoblasts is ensured. This paper is mainly focused on the preparation and characterization of cements and the studies of elution kinetics and bactericidal effects. Developed formulations are proposed as spacers for the treatment of infected arthroplasties, but also, they could be applied in other antibiotic devices to treat relevant bone-related infection diseases.
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Investigation of Linezolid Resistance in Staphylococci and Enterococci. J Clin Microbiol 2016; 54:1289-94. [PMID: 26935728 DOI: 10.1128/jcm.01929-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 01/27/2016] [Indexed: 12/23/2022] Open
Abstract
The objective of this study was to investigate an apparent increase in linezolid-nonsusceptible staphylococci and enterococci following a laboratory change in antimicrobial susceptibility testing from disk diffusion to an automated susceptibility testing system. Isolates with nonsusceptible results (n = 27) from Vitek2 were subjected to a battery of confirmatory testing which included disk diffusion, Microscan broth microdilution, Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution, gradient diffusion (Etest), 23S rRNA gene sequencing, and cfr PCR. Our results show that there is poor correlation between methods and that only 70 to 75% of isolates were confirmed as linezolid resistant with alternative phenotypic testing methods (disk diffusion, Microscan broth microdilution, CLSI broth microdilution, and Etest). 23S rRNA gene sequencing identified mutations previously associated with linezolid resistance in 16 (59.3%) isolates, and the cfr gene was detected in 3 (11.1%) isolates. Mutations located at positions 2576 and 2534 of the 23S rRNA gene were most common. In addition, two previously undescribed variants (at positions 2083 and 2345 of the 23S rRNA gene) were also identified and may contribute to linezolid resistance.
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Tekin A, Dal T, Deveci Ö, Tekin R, Özcan N, Atmaca S, Dayan S. In vitro susceptibility to methicillin, vancomycin and linezolid of staphylococci isolated from bloodstream infections in eastern Turkey. Braz J Microbiol 2014; 45:829-33. [PMID: 25477914 PMCID: PMC4204965 DOI: 10.1590/s1517-83822014000300010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Accepted: 12/13/2013] [Indexed: 12/02/2022] Open
Abstract
Staphylococcus species are one of the major causes of bacterial bloodstream infections. Multi-resistant staphylococci infections are major therapeutic problems. This study was aimed to detect methicillin, linezolid and vancomycin susceptibilities of Staphylococcus isolates. A total of 870 Staphylococcus strains isolated from blood cultures of hospitalized patients with BSI. Antimicrobial susceptibilities of methicillin, linezolid and vancomycin were detected according to the Clinical and Laboratory Standards Institute (CLSI). A total of 771 (88.6%) isolates were coagulase-negative staphylococci (CoNS). 700 (80.5%) isolates were methicillin-resistant (MR) and 170 (19.5%) were methicillin-susceptible (MS). All the MS isolates were also susceptible to linezolid. However 15 (1.7%) of MR strains were resistant to linezolid. The minimum inhibitory concentration range for the linezolid-resistant isolates by Etest was 6–32 μg/mL. The difference between linezolid susceptibilities for MS and MR staphylococci was not quite statistically significant (p = 0.052). There was no statistically significant difference between S. aureus and CoNS isolates for linezolid susceptibility. All of the isolates were susceptible to vancomycin. In conclusion, linezolid is currently an efficient option for the treatment of methicillin-resistant staphylococci infections.
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Affiliation(s)
- Alicem Tekin
- Department of Microbiology and Clinical Microbiology Medical Faculty Dicle University Diyarbakir Turkey Department of Microbiology and Clinical Microbiology, Medical Faculty, Dicle University, Diyarbakir, Turkey
| | - Tuba Dal
- Department of Microbiology and Clinical Microbiology Medical Faculty Dicle University Diyarbakir Turkey Department of Microbiology and Clinical Microbiology, Medical Faculty, Dicle University, Diyarbakir, Turkey
| | - Özcan Deveci
- Department of Clinical Microbiology and Infectious Diseases Medical Faculty Dicle University Diyarbakir Turkey Department of Clinical Microbiology and Infectious Diseases, Medical Faculty, Dicle University, Diyarbakir, Turkey
| | - Recep Tekin
- Department of Clinical Microbiology and Infectious Diseases Medical Faculty Dicle University Diyarbakir Turkey Department of Clinical Microbiology and Infectious Diseases, Medical Faculty, Dicle University, Diyarbakir, Turkey
| | - Nida Özcan
- Department of Microbiology and Clinical Microbiology Medical Faculty Dicle University Diyarbakir Turkey Department of Microbiology and Clinical Microbiology, Medical Faculty, Dicle University, Diyarbakir, Turkey
| | - Selahattin Atmaca
- Department of Microbiology and Clinical Microbiology Medical Faculty Dicle University Diyarbakir Turkey Department of Microbiology and Clinical Microbiology, Medical Faculty, Dicle University, Diyarbakir, Turkey
| | - Saim Dayan
- Department of Clinical Microbiology and Infectious Diseases Medical Faculty Dicle University Diyarbakir Turkey Department of Clinical Microbiology and Infectious Diseases, Medical Faculty, Dicle University, Diyarbakir, Turkey
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Comparison of commercial antimicrobial susceptibility test methods for testing of Staphylococcus aureus and Enterococci against vancomycin, daptomycin, and linezolid. J Clin Microbiol 2014; 52:2216-22. [PMID: 24719445 DOI: 10.1128/jcm.00957-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Three commercial antimicrobial susceptibility testing (AST) methods were compared to broth microdilution for testing of Staphylococcus aureus and enterococci against vancomycin, daptomycin, and linezolid. Despite high levels of categorical agreement and essential agreement, vancomycin MICs determined by MicroScan were often 1 log2 concentration higher and MICs determined by Phoenix 1 log2 concentration lower. Daptomycin MICs were 1 to 2 log2 concentrations higher by all AST methods, except Etest, potentially impacting definitive antimicrobial therapy for bloodstream infections due to these organisms.
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Mendes RE, Deshpande LM, Jones RN. Linezolid update: stable in vitro activity following more than a decade of clinical use and summary of associated resistance mechanisms. Drug Resist Updat 2014; 17:1-12. [PMID: 24880801 DOI: 10.1016/j.drup.2014.04.002] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Linezolid, approved for clinical use since 2000, has become an important addition to the anti-Gram-positive infection armamentarium. This oxazolidinone drug has in vitro and in vivo activity against essentially all Gram-positive organisms, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). The in vitro activity of linezolid was well documented prior to its clinical application, and several ongoing surveillance studies demonstrated consistent and potent results during the subsequent years of clinical use. Emergence of resistance has been limited and associated with invasive procedures, deep organ involvement, presence of foreign material and mainly prolonged therapy. Non-susceptible organisms usually demonstrate alterations in the 23S rRNA target, which remain the main resistance mechanism observed in enterococci; although a few reports have described the detection of cfr-mediated resistance in Enterococcus faecalis. S. aureus isolates non-susceptible to linezolid remain rare in large surveillance studies. Most isolates harbour 23S rRNA mutations; however, cfr-carrying MRSA isolates have been observed in the United States and elsewhere. It is still uncertain whether the occurrences of such isolates are becoming more prevalent. Coagulase-negative isolates (CoNS) resistant to linezolid were uncommon following clinical approval. Surveillance data have indicated that CoNS isolates, mainly Staphylococcus epidermidis, currently account for the majority of Gram-positive organisms displaying elevated MIC results to linezolid. In addition, these isolates frequently demonstrate complex and numerous resistance mechanisms, such as alterations in the ribosomal proteins L3 and/or L4 and/or presence of cfr and/or modifications in 23S rRNA. The knowledge acquired during the past decades on this initially used oxazolidinone has been utilized for developing new candidate agents, such as tedizolid and radezolid, and as linezolid patents soon begin to expire, generic brands will certainly become available. These events will likely establish a new chapter for this successful class of antimicrobial agents.
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Affiliation(s)
| | | | - Ronald N Jones
- JMI Laboratories, North Liberty, IA 52317, USA; Tufts University School of Medicine, Boston, MA 02111, USA
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Palavecino EL. Clinical, epidemiologic, and laboratory aspects of methicillin-resistant Staphylococcus aureus infections. Methods Mol Biol 2014; 1085:1-24. [PMID: 24085687 DOI: 10.1007/978-1-62703-664-1_1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen responsible for both hospital and community onset disease. Resistance to methicillin in S. aureus is mediated by PBP2a, a penicillin-binding protein with low affinity to beta-lactams, encoded by the mecA gene. Accurate susceptibility testing of S. aureus isolates and screening of patients for colonization with MRSA are important tools to limit the spread of this organism. This review focuses on the clinical significance of MRSA infections and new approaches for the laboratory diagnosis and epidemiologic typing of MRSA strains.
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Performance of Vitek 2 for antimicrobial susceptibility testing of Staphylococcus spp. and Enterococcus spp. J Clin Microbiol 2013; 52:392-7. [PMID: 24478467 DOI: 10.1128/jcm.02432-13] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vitek 2 (bioMérieux, Inc., Durham, NC) is a widely used commercial antimicrobial susceptibility testing system. We compared MIC results obtained by Vitek 2 to those obtained by the Clinical and Laboratory Standards Institute (CLSI) broth microdilution (BMD) reference method for 134 staphylococcal and 84 enterococcal clinical isolates. Nineteen agents were evaluated, including all those available on Vitek 2 for testing staphylococci and enterococci. The resistance phenotypes tested included methicillin-resistant Staphylococcus aureus (MRSA) (n = 58), S. aureus with inducible clindamycin resistance (ICR) (n = 30), trimethoprim-sulfamethoxazole-resistant MRSA (n = 10), vancomycin-resistant Enterococcus (n = 37), high-level gentamicin-resistant Enterococcus (n = 15), linezolid-resistant Enterococcus (n = 5), and daptomycin-nonsusceptible Enterococcus faecalis (n = 6). For the staphylococci, there was 98.9% categorical agreement (CA). There was one very major error (VME) for gentamicin in a Staphylococcus hominis isolate, six VMEs for inducible clindamycin in S. aureus isolates, and two major errors (ME) for daptomycin in an S. aureus and a Staphylococcus epidermidis isolate. For enterococci, there was 97.3% CA. Two VMEs were observed for daptomycin in isolates of E. faecalis and 2 ME, 1 for high-level gentamicin resistance and 1 for nitrofurantoin, in E. faecium isolates. Overall, there was 98.3% CA and 99% essential agreement for the testing of staphylococci and enterococci by the Vitek 2. With the exception of detecting ICR in S. aureus, Vitek 2 performed reliably for antimicrobial susceptibility testing of staphylococci and enterococci.
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Gu B, Kelesidis T, Tsiodras S, Hindler J, Humphries RM. The emerging problem of linezolid-resistant Staphylococcus. J Antimicrob Chemother 2013; 68:4-11. [PMID: 22949625 PMCID: PMC8445637 DOI: 10.1093/jac/dks354] [Citation(s) in RCA: 241] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The oxazolidinone antibiotic linezolid has demonstrated potent antimicrobial activity against Gram-positive bacterial pathogens, including methicillin-resistant staphylococci. This article systematically reviews the published literature for reports of linezolid-resistant Staphylococcus (LRS) infections to identify epidemiological, microbiological and clinical features for these infections. Linezolid remains active against >98% of Staphylococcus, with resistance identified in 0.05% of Staphylococcus aureus and 1.4% of coagulase-negative Staphylococcus (CoNS). In all reported cases, patients were treated with linezolid prior to isolation of LRS, with mean times of 20.0 ± 47.0 months for S. aureus and 11.0 ± 8.0 days for CoNS. The most common mechanisms for linezolid resistance were mutation (G2576T) to the 23S rRNA (63.5% of LRSA and 60.2% of LRCoNS) or the presence of a transmissible cfr ribosomal methyltransferase (54.5% of LRSA and 15.9% of LRCoNS). The emergence of linezolid resistance in Staphylococcus poses significant challenges to the clinical treatment of infections caused by these organisms, and in particular CoNS.
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Affiliation(s)
- Bing Gu
- Department of Laboratory Medicine, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
- National Key Clinical Department of Laboratory Medicine, Nanjing 210029, China
- UCLA David Geffen School of Medicine, Department of Pathology and Laboratory Medicine, Los Angeles, California, USA
| | - Theodoros Kelesidis
- UCLA David Geffen School of Medicine, Division of Infectious Diseases, Los Angeles, California, USA
| | - Sotirios Tsiodras
- 4th Department of Internal Medicine, University of Athens Medical School, Athens, Greece
| | - Janet Hindler
- UCLA David Geffen School of Medicine, Department of Pathology and Laboratory Medicine, Los Angeles, California, USA
| | - Romney M. Humphries
- UCLA David Geffen School of Medicine, Department of Pathology and Laboratory Medicine, Los Angeles, California, USA
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Ikeda-Dantsuji Y, Nakae T, Ariyoshi K, Mizuno H, Moriyama H, Nagura O, Suwabe A, Fukuchi K, Honda J, Kaku M, Kohno S, Mikamo H, Niki Y, Takesue Y, Tomono K, Yanagihara K, Hanaki H. Limited detectability of linezolid-resistant Staphylococcus aureus by the Etest method and its improvement using enriched media. J Med Microbiol 2012; 61:998-1002. [DOI: 10.1099/jmm.0.043695-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
| | - Taiji Nakae
- Laboratory for Antimicrobial Agents, Kitasato University, Tokyo, Japan
| | - Koichi Ariyoshi
- Department of Laboratory Medicine, Yamaguchi University Hospital, Yamaguchi, Japan
| | - Hidekazu Mizuno
- Department of Laboratory Medicine, Yamaguchi University Hospital, Yamaguchi, Japan
| | - Hidehiko Moriyama
- Department of Laboratory Medicine, Shimane University Hospital, Shimane, Japan
| | - Osanori Nagura
- Department of Laboratory Medicine, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Akira Suwabe
- Department of Laboratory Medicine, Iwate Medical University School of Medicine, Morioka, Iwate, Japan
| | - Kunihiko Fukuchi
- Department of Laboratory Medicine, Showa University School of Medicine, Tokyo, Japan
| | - Junichi Honda
- Department of Infection Control, St Mary’s Hospital, Fukuoka, Japan
| | - Mitsuo Kaku
- Central Clinical Laboratory, Department of Infection Control and Laboratory Diagnostics, Internal Medicine, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Shigeru Kohno
- The Second Department of Internal Medicine, Nagasaki University School of Medicine, Japan
| | - Hiroshige Mikamo
- Department of Infection Control and Prevention, Aichi Medical University, Aichi, Japan
| | - Yoshihito Niki
- Department of Clinical Infectious Diseases, Showa University School of Medicine, Tokyo, Japan
| | - Yoshio Takesue
- Department of Infection Control and Prevention, Hyogo College of Medicine, Hyogo, Japan
| | - Kazunori Tomono
- Department of Clinical Infectious Disease, Osaka University School of Medicine, Osaka, Japan
| | - Katsunori Yanagihara
- Department of Laboratory Medicine, Nagasaki University School of Medicine, Nagasaki, Japan
| | - Hideaki Hanaki
- Laboratory for Antimicrobial Agents, Kitasato University, Tokyo, Japan
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Characterization of nasal and blood culture isolates of methicillin-resistant Staphylococcus aureus from patients in United States Hospitals. Antimicrob Agents Chemother 2011; 56:1324-30. [PMID: 22155818 DOI: 10.1128/aac.05804-11] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
A total of 299 nares and 194 blood isolates of methicillin-resistant Staphylococcus aureus (MRSA), each recovered from a unique patient, were collected from 23 U.S. hospitals from May 2009 to March 2010. All isolates underwent spa and staphylococcal cassette chromosome mec element (SCCmec) typing and antimicrobial susceptibility testing; a subset of 84 isolates was typed by pulsed-field gel electrophoresis (PFGE) using SmaI. Seventy-six spa types were observed among the isolates. Overall, for nasal isolates, spa type t002-SCCmec type II (USA100) was the most common strain type (37% of isolates), while among blood isolates, spa type t008-SCCmec type IV (USA300) was the most common (39%). However, the proportion of all USA100 and USA300 isolates varied by United States census region. Nasal isolates were more resistant to tobramycin and clindamycin than blood isolates (55.9% and 48.8% of isolates versus 36.6% and 39.7%, respectively; for both, P < 0.05). The USA300 isolates were largely resistant to fluoroquinolones. High-level mupirocin resistance was low among all spa types (<5%). SCCmec types III and VIII, which are rare in the United States, were observed along with several unusual PFGE types, including CMRSA9, EMRSA15, and the PFGE profile associated with sequence type 239 (ST239) isolates. Typing data from this convenience sample suggest that in U.S. hospitalized patients, USA100 isolates of multiple spa types, while still common in the nares, have been replaced by USA300 isolates as the predominant MRSA strain type in positive blood cultures.
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Idelevich EA, von Eiff C, Friedrich AW, Iannelli D, Xia G, Peters G, Peschel A, Wanninger I, Becker K. In vitro activity against Staphylococcus aureus of a novel antimicrobial agent, PRF-119, a recombinant chimeric bacteriophage endolysin. Antimicrob Agents Chemother 2011; 55:4416-9. [PMID: 21746950 PMCID: PMC3165309 DOI: 10.1128/aac.00217-11] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 04/07/2011] [Accepted: 06/24/2011] [Indexed: 11/20/2022] Open
Abstract
Antistaphylococcal activity of the novel chimeric endolysin PRF-119 was evaluated with the microdilution method. The MIC(50) and MIC(90) of 398 methicillin-susceptible Staphylococcus aureus isolates were 0.098 μg/ml and 0.391 μg/ml, respectively (range, 0.024 to 0.780 μg/ml). Both the MIC(50) and MIC(90) values of 776 methicillin-resistant S. aureus isolates were 0.391 μg/ml (range, 0.024 to 1.563 μg/ml). All 192 clinical isolates of coagulase-negative staphylococci exhibited MIC values of >50 μg/ml. In conclusion, PRF-119 exhibited very good activity specifically against S. aureus.
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Affiliation(s)
- Evgeny A. Idelevich
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Christof von Eiff
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | | | | | - Guoqing Xia
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Georg Peters
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Andreas Peschel
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | | | - Karsten Becker
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
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Abstract
This review aims to discuss expert systems in general and how they may be used in medicine as a whole and clinical microbiology in particular (with the aid of interpretive reading). It considers rule-based systems, pattern-based systems, and data mining and introduces neural nets. A variety of noncommercial systems is described, and the central role played by the EUCAST is stressed. The need for expert rules in the environment of reset EUCAST breakpoints is also questioned. Commercial automated systems with on-board expert systems are considered, with emphasis being placed on the "big three": Vitek 2, BD Phoenix, and MicroScan. By necessity and in places, the review becomes a general review of automated system performances for the detection of specific resistance mechanisms rather than focusing solely on expert systems. Published performance evaluations of each system are drawn together and commented on critically.
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Affiliation(s)
- Trevor Winstanley
- Department of Microbiology, Royal Hallamshire Hospital, Sheffield, United Kingdom.
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Endimiani A, Hujer KM, Hujer AM, Kurz S, Jacobs MR, Perlin DS, Bonomo RA. Are we ready for novel detection methods to treat respiratory pathogens in hospital-acquired pneumonia? Clin Infect Dis 2011; 52 Suppl 4:S373-83. [PMID: 21460299 PMCID: PMC3106236 DOI: 10.1093/cid/cir054] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Hospital-acquired pneumonia represents one of the most difficult treatment challenges in infectious diseases. Many studies suggest that the timely administration of appropriate, pathogen-directed therapy can be lifesaving. Because results of culture and antimicrobial susceptibility testing can take 48 h or longer, physicians currently rely on clinical, epidemiological, and demographic factors to assist with the choice of empiric therapy for antibiotic-resistant pathogens. At present, a number of rapid molecular tests are being developed that identify pathogens and the presence of genetic determinants of antimicrobial resistance (eg, GeneXpert [Cepheid], ResPlex [Qiagen], FilmArray [Idaho Technologies], and Microarray [Check-Points]). In this review, the potential impact that molecular diagnostics has to identify and characterize pathogens that cause hospital-acquired bacterial pneumonia at an early stage is examined. In addition, a perspective on a novel technology, polymerase chain reaction followed by electrospray ionization mass spectrometry, is presented, and its prospective use in the diagnosis of pneumonia is also discussed. The complexities of the pulmonary microbiome represent a novel challenge to clinicians, but many questions still remain even as these technologies improve.
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Affiliation(s)
- Andrea Endimiani
- Department of Medicine
- Department of Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio
| | - Kristine M. Hujer
- Department of Medicine
- Department of Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio
| | - Andrea M. Hujer
- Department of Medicine
- Department of Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio
| | - Sebastian Kurz
- Department of Medicine
- Department of Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio
| | | | - David S. Perlin
- Public Health Research Institute
- Department of Microbiology and Molecular Genetics, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey
| | - Robert A. Bonomo
- Department of Medicine
- Department of Pharmacology
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine
- Department of Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio
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Scheetz MH, Knechtel SA, Postelnick MJ, Malczynski M, Qi C. Differences in clinical outcomes in patients with vancomycin-resistant enterococci according to linezolid susceptibility. Pharmacotherapy 2011; 30:1221-8. [PMID: 21114389 DOI: 10.1592/phco.30.12.1221] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
STUDY OBJECTIVE To evaluate the differences in clinical outcomes in patients with linezolid-intermediate or -resistant vancomycin-resistant enterococci (LIRVRE) isolates, as defined by the presence of the G2576T mutation, compared with patients who had linezolid-susceptible VRE (LSVRE) isolates in order to further discern the clinical relevance of linezolid resistance associated with this mutation. DESIGN Retrospective cohort study. SETTING Large tertiary care academic medical center. PATIENTS Eighteen adults (mean age 55.4 yrs) with LIRVRE (case patients) who were frequency matched to 54 adults (mean age 58.1 yrs) with LSVRE (control patients) in a 1:3 ratio based on site of culture and VRE species. MEASUREMENTS AND MAIN RESULTS Linezolid resistance was determined by phenotype and genotype (G2576T mutation by polymerase chain reaction). Patients with LIRVRE received more linezolid before isolation of the organism than did those with LSVRE (mean 8.6 vs 0.2 days, p<0.001). No difference in mortality was found; however, compared with controls, patients with LIRVRE were more likely to be transferred to the intensive care unit (56% vs 28%, p=0.032), had more surgical procedures for VRE (39% vs 15%, p=0.029), and had more echocardiograms performed (44% vs 19%, p=0.028) as a result of their VRE. Multivariate analysis revealed that surviving case patients had an increased duration of culture positivity of approximately 1.5 days (p=0.049) and a near statistically significant increase of postculture length of stay of approximately 2 days (p=0.053). CONCLUSION The clinical relevance of the G2576T mutation among enterococci remains unclear; however, the increased morbidity and resource utilization among patients with LIRVRE is a finding of concern. Careful monitoring of genotypically confirmed LIRVRE emergence and ongoing epidemiologic studies will be critical to better characterize the clinical relevance of linezolid resistance.
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Affiliation(s)
- Marc H Scheetz
- Department of Pharmacy, Northwestern Memorial Hospital, Chicago, Illinois, USA.
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Linezolid Resistance in Staphylococci. Pharmaceuticals (Basel) 2010; 3:1988-2006. [PMID: 27713338 PMCID: PMC4036669 DOI: 10.3390/ph3071988] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 06/03/2010] [Accepted: 06/23/2010] [Indexed: 11/21/2022] Open
Abstract
Linezolid, the first oxazolidinone to be used clinically, is effective in the treatment of infections caused by various Gram-positive pathogens, including multidrug resistant enterococci and methicillin-resistant Staphylococus aureus. It has been used successfully for the treatment of patients with endocarditis and bacteraemia, osteomyelitis, joint infections and tuberculosis and it is often used for treatment of complicated infections when other therapies have failed. Linezolid resistance in Gram-positive cocci has been encountered clinically as well as in vitro, but it is still a rare phenomenon. The resistance to this antibiotic has been, until now, entirely associated with distinct nucleotide substitutions in domain V of the 23S rRNA genes. The number of mutated rRNA genes depends on the dose and duration of linezolid exposure and has been shown to influence the level of linezolid resistance. Mutations in associated ribosomal proteins also affect linezolid activity. A new phenicol and clindamycin resistance phenotype has recently been found to be caused by an RNA methyltransferase designated Cfr. This gene confers resistance to lincosamides, oxazolidinones, streptogramin A, phenicols and pleuromutilins, decrease the susceptibility of S. aureus to tylosin, to josamycin and spiramycin and thus differs from erm rRNA methylase genes. Research into new oxazolidinones with improved characteristics is ongoing. Data reported in patent applications demonstrated that some oxazolidinone derivatives, also with improved characteristics with respect to linezolid, are presently under study: at least three of them are in an advanced phase of development.
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Raponi G, Ghezzi MC, Gherardi G, Lorino G, Dicuonzo G. Analysis of methods commonly used for glycopeptide and oxazolidinone susceptibility testing in Enterococcus faecium isolates. J Med Microbiol 2010; 59:672-678. [DOI: 10.1099/jmm.0.016444-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The susceptibility to teicoplanin, vancomycin and linezolid of 30 clinical isolates of Enterococcus faecium was tested by Vitek 2, Phoenix, Etest, broth microdilution and disc diffusion tests. The vanA and vanB resistance genes and the 23S rRNA gene G2576T mutation were detected by PCR and PCR-RFLP, respectively. Resistance rates to teicoplanin ranged from 3 % for Vitek 2 to 57.6 % for the Phoenix test, and those to vancomycin ranged from 56.7 % for Vitek 2 to 86.7 % for the Phoenix test. Only two out of 25 strains carrying the vanA gene were univocally recognized as the VanA phenotype. The only strain with the G2576T mutation did not carry the vanA gene and showed resistance to linezolid by the disc diffusion, Vitek 2 and broth dilution methods (MIC >8 μg ml−1), but was susceptible when tested with the Phoenix test and Etest (MIC ≤4 μg ml−1). Therefore, the resistance to glycopeptides and linezolid was not univocally detected by the susceptibility testing methods used in this study.
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Affiliation(s)
- Giammarco Raponi
- Dipartimento di Scienze di Sanità Pubblica, ‘Sapienza’ University of Rome, Rome, Italy
| | - Maria Cristina Ghezzi
- Dipartimento di Scienze di Sanità Pubblica, ‘Sapienza’ University of Rome, Rome, Italy
| | - Giovanni Gherardi
- Dipartimento di Scienze Biomediche, ‘Campus Bio-Medico’ University, Rome, Italy
| | - Giulia Lorino
- Dipartimento di Scienze di Sanità Pubblica, ‘Sapienza’ University of Rome, Rome, Italy
| | - Giordano Dicuonzo
- Dipartimento di Scienze Biomediche, ‘Campus Bio-Medico’ University, Rome, Italy
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Jones RN, Ross JE, Bell JM, Utsuki U, Fumiaki I, Kobayashi I, Turnidge JD. Zyvox® Annual Appraisal of Potency and Spectrum program: linezolid surveillance program results for 2008. Diagn Microbiol Infect Dis 2009; 65:404-13. [DOI: 10.1016/j.diagmicrobio.2009.10.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Accepted: 10/04/2009] [Indexed: 10/20/2022]
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Kuper KM, Boles DM, Mohr JF, Wanger A. Antimicrobial Susceptibility Testing: A Primer for Clinicians. Pharmacotherapy 2009; 29:1326-43. [DOI: 10.1592/phco.29.11.1326] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Wang JL, Hsueh PR. Therapeutic options for infections due to vancomycin-resistant enterococci. Expert Opin Pharmacother 2009; 10:785-96. [PMID: 19351228 DOI: 10.1517/14656560902811811] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Vancomycin-resistant enterococci (VRE) are an important cause of nosocomial infection occurring in critical care or immunocompromised patients. OBJECTIVES To provide updated information about therapeutic options for VRE infection. METHODS MEDLINE, EMBASE, and the Cochrane Library were searched to identify in vitro susceptibility data of VRE isolates, randomized and non-randomized controlled trials, case series, and cohort studies of VRE therapy published before 31 July 2008. RESULTS/CONCLUSION The updated in vitro susceptibility data for VRE show high resistance to ampicillin and aminoglycosides. Quinupristin-dalfopristin is limited by its lack of activity against vancomycin-resistant Enterococcus faealis and its musculoskeletal side effects. Emerging linezolid resistance has been reported to cause hospital spread and may be related to prolonged linezolid use. Quinupristin-dalfopristin resistance is usually linked to agricultural use of streptogramin. Nitrofurantoin and fosfomycin are alternatives in uncomplicated VRE urinary tract infection. Daptomycin and tigecycline have shown excellent potential for treating VRE infection.
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Affiliation(s)
- Jiun-Ling Wang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
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Jones RN, Kohno S, Ono Y, Ross JE, Yanagihara K. ZAAPS International Surveillance Program (2007) for linezolid resistance: results from 5591 Gram-positive clinical isolates in 23 countries. Diagn Microbiol Infect Dis 2009; 64:191-201. [PMID: 19500528 DOI: 10.1016/j.diagmicrobio.2009.03.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Accepted: 03/04/2009] [Indexed: 01/06/2023]
Abstract
The 2007 ZAAPS Program reports the results from the 6th year of oxazolidinone (linezolid) resistance surveillance among Gram-positive pathogens from 23 nations. For 2007, a total of 5591 organisms were systematically sampled from Asia, Australia, Canada, Europe, and Latin America including Staphylococcus aureus (3000 isolates, 38.2% methicillin resistant), coagulase-negative staphylococci (CoNS, 716 isolates), enterococci (906 isolates), Streptococcus pneumoniae (452 isolates), viridans group streptococci (155 isolates), and beta-hemolytic streptococci (362 isolates). The overall linezolid MIC distribution (MIC(50) and MIC(90) at 1 and 2 microg/mL, respectively) was unchanged since 2002. At published linezolid breakpoints (, or = 2 microg/mL), all streptococci were susceptible; however, resistance was observed very rarely among S. aureus (0.03%), CoNS (0.28%), and the enterococci (0.11%, 0.55% intermediate). These oxazolidinone-nonsusceptible isolates occurred in Ireland, Italy, China, and Brazil (9 strains), and the rate was not increased since 2006. The detected mechanism of resistance was G2576 target mutations; no cfr-mediated patterns were observed. Clonal outbreaks with patient-to-patient dissemination were documented in 1 Italian site. Linezolid appears to retain excellent activity against monitored Gram-positive pathogens at a level of >99.8%.
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Vancomycin MICs for Staphylococcus aureus vary by detection method and have subtly increased in a pediatric population since 2005. J Clin Microbiol 2009; 47:1628-30. [PMID: 19403769 DOI: 10.1128/jcm.00407-09] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vancomycin MICs for Staphylococcus aureus isolates in a pediatric hospital with a high rate of staphylococcal infections were examined for any increase over a 7-year period. A broth microdilution scheme allowed direct comparison of the MICs generated by this method to MICs generated by Etest. MICs generated by both methods were determined with the same inoculum suspension. One hundred sixty-five S. aureus isolates were selected on the basis of the patients having been bacteremic or having received vancomycin as the definitive therapy for their infections. Of the 165 isolates, 117 were methicillin-resistant S. aureus and 48 were methicillin-susceptible S. aureus. Forty-seven were acquired in the hospital (nosocomial), 56 were community acquired, and 62 were community onset-health care associated. All but one isolate tested by broth microdilution had MICs of < 1.0 microg/ml, while 96% of these same isolates tested by Etest had MICs of > or = 1 microg/ml. A significant increase in MICs that occurred after study year 4 (2004 to 2005) was demonstrated by the Etest (P < 0.00007) but not by broth microdilution. MICs were not different for isolates of community or health care origin, regardless of methodology. The proportion of isolates with Etest MICs of < 1 and > or = 1 microg/ml between children with bacteremia for < or = 5 days and > 5 days (P = 0.3) was not different. We conclude that MICs for pediatric isolates have increased slightly since 2005 and therapeutic decisions based on vancomycin MICs need to be made by considering the methodology used.
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Abstract
An accurate, appropriately collated antibiogram represents an integral resource for health care providers when assessing bacterial resistance and guiding antimicrobial selection and formulary decisions. Interpretation of bacterial susceptibility statistics is problematic yet frequent and unrecognized pitfalls may be avoided by following the M39-A2 guidelines to ensure correct analysis and presentation of cumulative antimicrobial susceptibility test data. This review addresses guideline recommendations related to antibiogram development, CLSI breakpoint interpretation, antimicrobial inclusion decisions, and the avoidance of duplicate and surveillance isolates. Unit-specific antibiograms in critical care units is encouraged for differentiation between hospital-wide ecology and these specific areas harboring more resistant pathogens. Antibiograms cannot track the emergence of microbial resistance during therapy and discrepancies exist between automated microbiology surveillance systems and their agreement with manual surveillance methods. When striving to improve overall patient outcomes, the use of a well-produced and disseminated antibiogram helps guide clinical decision making for patients requiring antimicrobial therapy.
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Affiliation(s)
- Edward H. Eiland
- Department of Pharmacy, Huntsville Hospital, Huntsville, Alabama,
| | | | - William Lindgren
- Department of Microbiology, Huntsville Hospital, Huntsville, Alabama
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40
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Anagnostakos K, Kelm J, Grün S, Schmitt E, Jung W, Swoboda S. Antimicrobial properties and elution kinetics of linezolid-loaded hip spacersin vitro. J Biomed Mater Res B Appl Biomater 2008; 87:173-8. [PMID: 18395822 DOI: 10.1002/jbm.b.31088] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Konstantinos Anagnostakos
- Klinik für Orthopädie und Orthopädische Chirurgie, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany.
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Increasing incidence of linezolid-intermediate or -resistant, vancomycin-resistant Enterococcus faecium strains parallels increasing linezolid consumption. Antimicrob Agents Chemother 2008; 52:2256-9. [PMID: 18391028 DOI: 10.1128/aac.00070-08] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clinical enterococcal resistance to linezolid is defined by the presence of the G2576T mutation. We evaluated the incidence of genetically proven linezolid resistance among vancomycin-resistant Enterococcus faecium strains and linezolid consumption for a possible association. A relationship was found (r(2) = 0.73, P = 0.03) and predicts increasing resistance with current trends of linezolid use.
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Fracalanzza SAP, Scheidegger EMD, Santos PFD, Leite PC, Teixeira LM. Antimicrobial resistance profiles of enterococci isolated from poultry meat and pasteurized milk in Rio de Janeiro, Brazil. Mem Inst Oswaldo Cruz 2007; 102:853-9. [PMID: 18060316 DOI: 10.1590/s0074-02762007005000120] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Accepted: 10/09/2007] [Indexed: 02/06/2023] Open
Abstract
The enterococci are important nosocomial pathogens with a remarkable capacity of expressing resistance to several antimicrobial agents. Their ubiquitous nature and resistance to adverse environmental conditions take account for their ability to colonize different habitats and for their potential for easy spreading through the food chain. In the present study we evaluated the distribution of species and antimicrobial susceptibility among enterococcal isolates recovered from food obtained in retail stores in Rio de Janeiro, Brazil. The following species were identified among 167 isolates obtained from poultry meat and 127 from pasteurized milk: Enterococcus faecalis (62.6%), E. casseliflavus (17.3%), E. durans (6.5%), E. gallinarum (3.0%), E. gilvus (2.4%), E. faecium (2.0%), E. hirae (1.4%), and E. sulfureus (1.0%). The overall percentages of antimicrobial resistant isolates were: 31.2 % to tetracycline, 23.8% to erythromycin, 11.3% to streptomycin, 4.3% to chloramphenicol, 3.9% to gentamicin, 1.4% to norfloxacin, 1.1% to imipenem, 0.7% to ciprofloxacin, nitrofurantoin, and penicillin, and 0.4% to ampicillin. Intermediate resistance was detected in frequencies varying from 0.5% for linezolid to 58.2% for erythromycin. None of the isolates showed resistance to glycopeptides. High-level resistance to aminoglycosides was observed in 13.1% of the isolates. Multiresistance was observed in E. faecalis, E. casseliflavus, E. faecium, E. gallinarum, E. durans and E. gilvus.
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