title: Glycopeptide resistance in coagulase-negative staphylococci isolated in blood cultures from patients with hematological malignancies during three decades.
abstract: The aim of this study was to determine if there was a long-term increase in glycopeptide minimum inhibitory concentration (MIC) values, MIC creep, among bloodstream isolates of Staphylococcus epidermidis and S. haemolyticus isolated from patients with hematological malignancies. We conducted a retrospective single-center study where all positive blood cultures of S. epidermidis (n = 387) and S. haemolyticus (n = 19) isolated from patients with hematological malignancies during three decades, 1980 to 2009, were re-evaluated for the presence of reduced susceptibility to vancomycin and teicoplanin. Three different methods for the detection of reduced susceptibility to glycopeptides were used; standard Etest, macromethod Etest, and glycopeptide resistance detection (GRD) Etest. The median MIC value for vancomycin was 2 mg/L. MIC values for vancomycin and teicoplanin did not show any statistically significant increase during the study period. The presence of heterogeneously glycopeptide-intermediate staphylococci (hGIS) was analyzed among 405 coagulase-negative staphylococci (CoNS) isolates. hGIS were found in 31-45% of the CoNS isolates by the macromethod Etest and in 53-67% by the GRD Etest during the three decades. In conclusion, we did not observe any long-term glycopeptide MIC creep determined by the standard Etest, although a high and increasing proportion of heterogeneous vancomycin resistance was observed.
authors: Department of Medicine, Division of Hematology, Örebro University Hospital, 701 85 Örebro, Sweden. erik.ahlstrand@orebroll.se
authors: E
authors: E
authors: Ahlstrand
authors: K
authors: K
authors: Svensson
authors: L
authors: L
authors: Persson
authors: U
authors: U
authors: Tidefelt
authors: B
authors: B
authors: Söderquist
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000150:complications / Q000382:microbiology*; D003030:Coagulase; D004352:Drug Resistance, Microbial; D006020:Glycopeptides / Q000494:pharmacology*; D019337:Hematologic Neoplasms / Q000150:complications; D006801:Humans; D016867:Immunocompromised Host; D008826:Microbial Sensitivity Tests; D012189:Retrospective Studies; D013045:Species Specificity; D013203:Staphylococcal Infections / Q000150:complications / Q000382:microbiology*; D013212:Staphylococcus epidermidis / Q000187:drug effects*; D041162:Staphylococcus haemolyticus / Q000187:drug effects*; D013548:Sweden; D017334:Teicoplanin / Q000494:pharmacology; D014640:Vancomycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D003030:Coagulase; D006020:Glycopeptides; D017334:Teicoplanin; D014640:Vancomycin