Abstract
The purpose of the study was to determine whether vancomycin-resistant strains ofStaphylococcus haemolyticus could be selected regardless of the initial MIC of vancomycin. Twenty-one bloodstream isolates ofStaphylococcus haemolyticus were studied by broth and agar selection methods. The broth method selected strains for which MICs of vancomycin ranged from 4 to 32 µg/ml and MBCs from 16 to>128 µg/ml. The agar method selected strains for which MICs ranged from 8 to 32 µg/ml and MBCs from 8 to>128 µg/ml. For comparison, seven strains ofStaphylococcus epidermidis were evaluated by the agar selection method. Final MICs of vancomycin ranged from 8 to 16 µg/ml; MBCs ranged from 16 to 64 µg/ml. Clearly, in vitro exposure to vancomycin can select strains ofStaphylococcus haemolyticus andStaphylococcus epidermidis for which MIC values are beyond the susceptible breakpoint.
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Herwaldt, L., Boyken, L. & Pfaller, M. In vitro selection of resistance to vancomycin in bloodstream isolates ofStaphylococcus haemolyticus andStaphylococcus epidermidis . Eur. J. Clin. Microbiol. Infect. Dis. 10, 1007–1012 (1991). https://doi.org/10.1007/BF01984921
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DOI: https://doi.org/10.1007/BF01984921