Staphylococcus aureus: the new adventures of a legendary pathogen.

Nosocomial infections with strains of methicillin-resistant Staphylococcus aureus (MRSA) began to emerge in the 1960s, are increasing in frequency, and tend to have worse outcomes than infections due to methicillin-susceptible S aureus. Community-associated MRSA infections emerged in the 1990s. Community-associated MRSA strains have up to now been epidemiologically and bacteriologically distinct from hospital-associated MRSA strains, but in a new twist, MRSA strains that have sofar been only community-associated are invading the hospital. Another worrisome trend is increasing resistance to vancomycin (Vancocin).