title: Vancomycin MIC creep in MRSA blood culture isolates from Germany: a regional problem?
abstract: The aim of this study was to assess the vancomycin MIC distribution for MRSA blood culture isolates over a period of six years in Germany. The study examined 287 MRSA isolates from blood cultures collected at several hospitals in two German cities between 2004 and 2009. The vancomycin MIC was determined by Etest. Genotypic features of the MRSA strains with vancomycin MIC ≥ 1 mg/L were determined by semiautomated repetitive-sequence-based polymerase chain reaction. The range of vancomycin MIC as determined by Etest was 0.25 to 2.0 mg/L. The geometric mean MIC increased by 1.34-fold in city A over the study period (p < 0.05), but there was no meaningful change in city B (a 1.09-fold increase, p > 0.05). Furthermore, in city A a shift in vancomycin MICs occurred as an increase in the percentage of isolates with MIC ≥ 1 mg/L from period one (2004-2006) to period two (2007-2009) (p < 0.0001). Typing results showed that in city A a single clone was predominant (55% of the creep isolates). In this study, the creep phenomenon seems to be a regional problem. We suggest that all hospitals should monitor their local status of elevated vancomycin MICs in invasive MRSA isolates.
authors.affiliation: Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Virchowstr 179, 45147 Essen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Kehrmann
authors.forename: M
authors.initials: M
authors.lastname: Kaase
authors.forename: F
authors.initials: F
authors.lastname: Szabados
authors.forename: S G
authors.initials: SG
authors.lastname: Gatermann
authors.forename: J
authors.initials: J
authors.lastname: Buer
authors.forename: P-M
authors.initials: PM
authors.lastname: Rath
authors.forename: J
authors.initials: J
authors.lastname: Steinmann
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000453:epidemiology* / Q000382:microbiology; D015373:Bacterial Typing Techniques; D001769:Blood / Q000382:microbiology*; D016000:Cluster Analysis; D005838:Genotype; D005858:Germany / Q000453:epidemiology; D006761:Hospitals; D006801:Humans; D020071:Interspersed Repetitive Sequences; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D058889:Molecular Typing; D016133:Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D014640:Vancomycin / Q000494:pharmacology*; D020713:Vancomycin Resistance
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin