Clinical, epidemiologic, and laboratory aspects of methicillin-resistant Staphylococcus aureus infections.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen responsible for both hospital and community onset disease. Resistance to methicillin in S. aureus is mediated by PBP2a, a penicillin-binding protein with low affinity to beta-lactams, encoded by the mecA gene. Accurate susceptibility testing of S. aureus isolates and screening of patients for colonization with MRSA are important tools to limit the spread of this organism. This review focuses on the clinical significance of MRSA infections and new approaches for the laboratory diagnosis and epidemiologic typing of MRSA strains.