Exposure of Staphylococcus aureus to subinhibitory concentrations of β-lactam antibiotics induces heterogeneous vancomycin-intermediate Staphylococcus aureus.

ABSTRACT: Glycopeptides are known to select for heterogeneous vancomycin-intermediate Staphylococcus aureus (h-VISA) from susceptible strains. In certain clinical situations, h-VISA strains have been isolated from patients without previous exposure to glycopeptides, such as cystic fibrosis patients, who frequently receive repeated treatments with beta-lactam antibiotics. Our objective was to determine whether prolonged exposure to beta-lactam antibiotics can induce h-VISA. We exposed 3 clinical vancomycin-susceptible methicillin-resistant Staphylococcus aureus (MRSA) strains to ceftazidime, ceftriaxone, imipenem, and vancomycin (as a control) at subinhibitory concentrations for 18 days in vitro. Population analyses showed progressive increases in vancomycin resistance; seven of the 12 derived strain

SUBMITTER: Roch M 

PROVIDER: S-EPMC4135816 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature