Changes in the epidemiology of methicillin-resistant Staphylococcus aureus in intensive care units in US hospitals, 1992-2003.

The proportion of Staphylococcus aureus isolates that were methicillin resistant (MRSA) increased from 35.9% in 1992 to 64.4% in 2003 for hospitals in the National Nosocomial Infections Surveillance system. During the same period, there was a decrease in resistance rates for several non- beta -lactam drugs among the MRSA isolates.