Methicillin-Resistant Staphylococcus aureus in Hospitals and Long-Term Care Facilities: Microbiology, Epidemiology, and Preventive Measures

Abstract

Strains of methicillin-resistant Staphylococcus aureus (MRSA) have become increasingly common in the United States and in many other countries since 1975. Although MRSA was recovered primarily in university and federal hospitals in this country during the late 1970s, these organisms are being encountered with increasing frequency in all types of hospitals, especially in the eastern half of the United States. Although there is a paucity of information available on the prevalence of MRSA in long-term care facilities, a few reports suggest that MRSA is also seen frequently in these settings. Because colonized patients are frequently transferred between hospitals and long-term care facilities, a continuing circuit of MRSA transmission occurs in areas where these organisms are prevalent. MRSA prevalence rates vary widely by locale and by type and size of hospital. In some geographic areas, the prevalence remains low, whereas in other areas, from 10% to 50% of all S aureus isolates recovered from patients in large medical centers are MRSA. Even within a given city, MRSA prevalence rates may vary widely among acute care hospitals.