Clinical isolates of Staphylococcus aureus with reduced susceptibility to vancomycin (VRSA) have been reported from Japan, the United States, and France. Although the isolates are considered intermediately resistant according to the National Committee for Clinical Laboratory Standards (NCCLS), they are already a cause of serious concern in the ever-worsening antibiotic crisis of today, because they are all methicillin-resistant S. aureus (MRSA) and they are isolated after prolonged and unsuccessful vancomycin therapy. Furthermore, a study in Japan showed a high prevalence of “hetero-VRSA,” MRSA strains that are susceptible to vancomycin according to NCCLS, but contain subpopulation of VRSA at the frequency of ≥10⁻⁶ and thus can be converted easily to full-blown VRSA upon exposure to the antibiotic. Recent reports from Seoul showed that hetero-VRSA is also prevalent in Korea.

This review is to examine the epidemiology, clinical significance, mechanisms, and laboratory detection of vancomycin resistance in clinical isolates of S. aureus; and to summarize infection control guidelines recommended by Centers for Disease Control and Prevention and others for this newly emerging nosocomial pathogen. (Korean J Clin Microbiol 1999;2:1-7)