April 1, 2003

Janet F. Hindler, MCLS

Antimicrobial resistance in Staphylococcus aureus is escalating at alarming rates. Methicillin- (oxacillin-) resistant S. aureus (MRSA), once considered a nosocomial pathogen, is now infecting “healthy” individuals in community settings. MRSA resistant to vancomycin was feared for many years, and vancomycin-resistant S. aureus (VRSA) made its appearance in 2002 by infecting two individuals in different parts of the U.S. S. aureus with intermediate susceptibility to vancomycin (VISA) has been noted in the U.S. as well. Because S. aureus is a common pathogen and antimicrobial resistance in S. aureus is a significant public health concern, clinical laboratorians must use acceptable test methods in order to detect resistance. In addition, the results of testing must be conveyed in a manner that stimulates appropriate action. This presentation provides background material on the problem of antimicrobial resistance in S. aureus and includes information that every clinical laboratorian who performs antimicrobial susceptibility tests and/or reports results should know.