Infection with Vancomycin-Resistant Staphylococcus aureus Containing the vanA Resistance Gene

Abstract

Until recently, vancomycin was the only uniformly effective treatment for staphylococcal infections. In 1997, the first clinical isolate of Staphylococcus aureus with reduced susceptibility to vancomycin was reported,1 and as of June 2002, eight confirmed infections with such strains had been reported in patients in the United States.2-6 The minimal inhibitory concentrations (MICs) of vancomycin reported for these isolates are in the intermediate range (8 to 16 μg per milliliter) according to interpretive criteria defined by the National Committee for Clinical Laboratory Standards.7 In June 2002, a clinical isolate of vancomycin-resistant S. aureus (VRSA) (MIC, >32 μg per milliliter) was identified.8 In this report, we describe our investigation of this infection, describe the mechanism of resistance, and discuss the clinical significance and public health implications of this finding.