Nina J Hos1, Nathalie Jazmati2, Danuta Stefanik2, Martin Hellmich3, Halil AlSael2, Winfried V Kern4, Siegbert Rieg4, Hilmar Wisplinghoff2, Harald Seifert5, Achim J Kaasch6. 1. Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Goldenfelsstr. 19-21, 50935 Cologne, Germany; Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany; German Centre for Infection Research, Partner Site Bonn-Cologne, Germany. 2. Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Goldenfelsstr. 19-21, 50935 Cologne, Germany. 3. Institute of Medical Statistics, Informatics and Epidemiology, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany. 4. Division of Infectious Diseases, Department of Medicine II, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany. 5. Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Goldenfelsstr. 19-21, 50935 Cologne, Germany; German Centre for Infection Research, Partner Site Bonn-Cologne, Germany. Electronic address: harald.seifert@uni-koeln.de. 6. Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Goldenfelsstr. 19-21, 50935 Cologne, Germany; Institute of Medical Microbiology and Hospital Hygiene, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
Abstract
OBJECTIVES: Elevated vancomycin minimum inhibitory concentrations (MIC) have been reported to adversely affect clinical outcome in methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI). We therefore examined the association between vancomycin MIC and outcome considering various potential confounders. METHODS: Clinical data and bacterial isolates were prospectively collected from patients with MRSA BSI from 2006 to 2012 as part of the Invasive Staphylococcus aureus Infection Cohort (INSTINCT) study. Antimicrobial susceptibility was assessed by Etest, broth microdilution (BMD) and VITEK 2. Bacterial genotypes were determined by spa typing. Using univariate and Cox regression analyses, we investigated the impact of low (≤1.0 mg/L) and high (≥1.5 mg/L) vancomycin Etest MIC on clinical outcomes. RESULTS: Ninety-one MRSA BSI episodes were included, of which 79 (86.8%) were caused by spa types t003, t032 and t045. High vancomycin MICs were seen only if using Etest but not confirmed using standard reference BMD. When episodes were stratified into low and high vancomycin Etest MIC groups, 30-day overall mortality was 34.5% and 27.3%, respectively (P = 0.64, OR 0.71; 95% confidence interval [CI] 0.27-1.79). Variables significantly associated with all-cause mortality in the Cox model were age (P = 0.003), acute physiology score (P = 0.0006), and Charlson comorbidity index (P = 0.018). CONCLUSIONS: Vancomycin MICs may vary dependent on testing methodologies and local MRSA epidemiology. The patients' underlying disease and individual comorbidities rather than elevated vancomycin MICs determine adverse clinical outcomes in MRSA BSI. Routine Etest MIC testing of MRSA isolates is of limited value for treatment decisions.
OBJECTIVES: Elevated vancomycin minimum inhibitory concentrations (MIC) have been reported to adversely affect clinical outcome in methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI). We therefore examined the association between vancomycin MIC and outcome considering various potential confounders. METHODS: Clinical data and bacterial isolates were prospectively collected from patients with MRSA BSI from 2006 to 2012 as part of the Invasive Staphylococcus aureusInfection Cohort (INSTINCT) study. Antimicrobial susceptibility was assessed by Etest, broth microdilution (BMD) and VITEK 2. Bacterial genotypes were determined by spa typing. Using univariate and Cox regression analyses, we investigated the impact of low (≤1.0 mg/L) and high (≥1.5 mg/L) vancomycin Etest MIC on clinical outcomes. RESULTS: Ninety-one MRSA BSI episodes were included, of which 79 (86.8%) were caused by spa types t003, t032 and t045. High vancomycin MICs were seen only if using Etest but not confirmed using standard reference BMD. When episodes were stratified into low and high vancomycin Etest MIC groups, 30-day overall mortality was 34.5% and 27.3%, respectively (P = 0.64, OR 0.71; 95% confidence interval [CI] 0.27-1.79). Variables significantly associated with all-cause mortality in the Cox model were age (P = 0.003), acute physiology score (P = 0.0006), and Charlson comorbidity index (P = 0.018). CONCLUSIONS:Vancomycin MICs may vary dependent on testing methodologies and local MRSA epidemiology. The patients' underlying disease and individual comorbidities rather than elevated vancomycin MICs determine adverse clinical outcomes in MRSA BSI. Routine Etest MIC testing of MRSA isolates is of limited value for treatment decisions.
Authors: R Falcón; E M Mateo; A Talaya; E Giménez; V Vinuesa; M Á Clari; D Navarro Journal: Eur J Clin Microbiol Infect Dis Date: 2017-07-25 Impact factor: 3.267
Authors: Natasha E Holmes; J Owen Robinson; Sebastiaan J van Hal; Wendy J Munckhof; Eugene Athan; Tony M Korman; Allen C Cheng; John D Turnidge; Paul D R Johnson; Benjamin P Howden Journal: BMC Infect Dis Date: 2018-03-05 Impact factor: 3.090