Clinical, epidemiologic and bacteriologic observations of an outbreak of methicillin-resistant Staphylococcus aureus at a large community hospital.

Over a 12 month period, 61 isolates of methicillin-resistant Staphylococcus aureus (MR-SA) were obtained in 23 hospitalized patients. Eight-six per cent of the patients were over 50 years of age, and 91 per cent were in the postoperative period. In 10 patients (42 per cent), MR-SA was the major pathogen, producing either pneumonia, empyema, osteomyelitis, lung abscess, enterocolitis, wound infection or bacteremia with sepsis. Three patients in this group died despite therapy with antibiotics with in vitro activity against these organisms. All the patients probably acquired their MR-SA in the hospital, and five carriers of the organism were identified among hospital personnel. This outbreak demonstrates the ability of MR-SA not only to colonize many patients in a relatively brief period of time, but also to produce serious disease.