en
Scientific article
English

High prevalence of isolates with reduced glycopeptide susceptibility in persistent or recurrent bloodstream infections due to methicillin-resistant Staphylococcus aureus

Published inAntimicrobial agents and chemotherapy, vol. 56, no. 3, p. 1258-1264
Publication date2012
Abstract

Reduced susceptibility to glycopeptides in methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates is considered a risk factor for failure of glycopeptide therapy. We compared the prevalences of MRSA isolates with reduced glycopeptide susceptibility in patients with versus without persistent or recurrent MRSA bloodstream infections. A retrospective cohort study at the University Hospital of Geneva identified 27 patients with persistent or recurrent clonally related MRSA bacteremic episodes over an 8-year period, which included 208 consecutive nosocomial MRSA bacteremic episodes. Vancomycin and teicoplanin MICs were determined by a modified macrodilution assay allowing improved detection of glycopeptide-intermediate MRSA isolates (GISA), characterized by elevated teicoplanin or/and vancomycin MICs (≥ 4 μg/ml). For 16 patients (59%), their pretherapy and/or posttherapy MRSA isolates showed elevated teicoplanin MICs, among which 10 (37%) concomitantly displayed elevated vancomycin MICs. In contrast, 11 other patients (41%) were persistently or recurrently infected with non-GISA isolates. In comparison, only 39 (22%) of 181 single isolates from patients with no microbiological evidence of persistent or recurrent infections showed elevated teicoplanin MICs, among which 14 (8%) concomitantly displayed elevated vancomycin MICs. Clinical, microbiological, and pharmacokinetic variables for patients persistently or recurrently infected with GISA or non-GISA isolates were similar. Bacteremic patients with a poor response to glycopeptide therapy had a 2.8-fold- and 4.8-fold-higher rates of MRSA isolates displaying elevated teicoplanin and vancomycin MICs, respectively, than patients with single isolates (P < 0.0001). Detection of elevated teicoplanin MICs may help to predict a poor response to glycopeptide therapy in MRSA bacteremic patients.

Keywords
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents/pharmacology/therapeutic use
  • Bacteremia/drug therapy/microbiology
  • Child, Preschool
  • Drug Resistance, Bacterial/drug effects
  • Female
  • Humans
  • Male
  • Methicillin-Resistant Staphylococcus aureus/drug effects/growth & development/isolation & purification
  • Microbial Sensitivity Tests
  • Middle Aged
  • Recurrence
  • Retrospective Studies
  • Staphylococcal Infections/drug therapy/microbiology
  • Teicoplanin/pharmacology/therapeutic use
  • Vancomycin/pharmacology/therapeutic use
Citation (ISO format)
UCKAY, Ilker et al. High prevalence of isolates with reduced glycopeptide susceptibility in persistent or recurrent bloodstream infections due to methicillin-resistant Staphylococcus aureus. In: Antimicrobial agents and chemotherapy, 2012, vol. 56, n° 3, p. 1258–1264. doi: 10.1128/AAC.05808-11
Main files (1)
Article (Published version)
accessLevelRestricted
Identifiers
ISSN of the journal0066-4804
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