Methicillin-resistant Staphylococcus aureus in extended-care facilities: experiences in a Veterans' Affairs nursing home and a review of the literature.

OBJECTIVES: To delineate the spread of methicillin-resistant Staphylococcus aureus (MRSA) in a nursing home care unit (NHCU), determine its consequences, and discuss this experience in the context of reports from other nursing homes.

DESIGN: Observational and descriptive; routine and special surveillance for MRSA, including a facility-wide prevalence survey; characterization of MRSA isolates by disk diffusion and agar dilution susceptibility studies and restriction enzyme analysis of plasmid (REAP) DNA.

SETTING AND PATIENTS: A 120-bed skilled nursing facility that is an integral part of the Veterans' Affairs Medical Center (VAMC), Portland, Oregon. The patients are predominantly elderly men with severe underlying diseases and functional impairments.

RESULTS: An asymptomatic carrier brought MRSA into the NHCU in December 1987. During the next 15 months, 24 additional MRSA cases were detected. A prevalence survey conducted in March 1989 indicated that 39 (34%) of the 114 patients and 8 (7%) of the 117 employees were colonized or infected with MRSA. All strains were resistant to ciprofloxacin. REAP DNA indicated that 37 of 41 strains recovered in the March survey had identical patterns. Although 16 episodes of MRSA infection occurred in NHCU residents during 1988 through 1989, the outbreak had little effect on overall patterns of infectious morbidity and mortality in the facility. The outbreak, however, did result in an increased MRSA caseload at the medical center's acute-care division.

CONCLUSIONS: During the last three years, MRSA colonization and infection have become common in the NHCU at the Portland VAMC; this experience parallels that reported by several nursing homes in other parts of the country.