Open AccessUnstable Vancomycin Heteroresistance Is Common among Clinical Isolates of Methiciliin-Resistant Staphylococcus aureus
Author(s) -
Nottasorn Plipat,
Gilat Livni,
H. Bertram,
Richard B. Thomson
Publication year - 2005
Publication title -
journal of clinical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.349
H-Index - 255
eISSN - 1070-633X
pISSN - 0095-1137
DOI - 10.1128/jcm.43.5.2494-2496.2005
Subject(s) - vancomycin , staphylococcus aureus , microbiology and biotechnology , biology , methicillin resistant staphylococcus aureus , micrococcaceae , antibiotics , medicine , antibacterial agent , bacteria , genetics
We tested 109 unique, vancomycin-susceptible, methicillin-resistant Staphylococcus aureus (MRSA) strains for vancomycin heteroresistance by a selection method, i.e., step-wise exposure of large inoculums to increasing concentrations of vancomycin. Although no strains demonstrated stable heteroresistance, 81 strains (74%) demonstrated unstable heteroresistance. Unstable heteroresistance is common among clinical isolates of MRSA and may represent a cause of therapeutic failure.