Methicillin-resistant Staphylococcus aureus: colonization and infection in a long-term care facility.

Objective: To assess methicillin-resistant Staphylococcus aureus (MRSA) colonization, transmission, and infection over a 1-year period in a long-term care facility with endemic MRSA.
Design: Monthly surveillance for MRSA colonization of nares, perineum, rectum, and wounds.
Setting: Long-term care facility attached to an acute care Veterans Affairs medical center.
Patients: All 341 patients in the facility had monthly surveillance cultures for 1 year.
Outcome Measurements: Colonization and infection with MRSA.
Main Results: The monthly MRSA colonization rate was 23% +/- 1.0%; colonization occurred most commonly in the nares and wounds. Poor functional status was associated with MRSA colonization. Most patients (65%) never acquired MRSA; 25% of patients were already colonized at admission to the facility or at the start of the study, and only 10% of newly admitted patients acquired MRSA while in the facility. These latter patients acquired several different strains in a pattern of acquisition similar to that generally seen within the facility. In the course of 1 year, only nine patients who acquired MRSA had a roommate with the same phage type; no clustering was evident, and none of these patients developed infection. Nine other patients (3%) developed MRSA infection; five of these patients required hospitalization, but none died as a result of infection.
Conclusions: In the long-term care facility in which our study took place, MRSA was endemic, and the infection rate was low. In such settings, the cost effectiveness of aggressive management of MRSA (widespread screening for MRSA and eradication with antimicrobial agents) needs to be assessed.