[Evolution of patient colonization with methicillin-resistant Staphylococcus aureus in a skilled nursing facility]

Methicillin-resistant Staphylococcus aureus (MRSA) asymptomatic colonization is common in long-term care facilities, but the burden of symptomatic infection appears to be low. It is not usually known whether a patient is colonized at the time of admission to the geriatric facility. Our purpose was to determine the prevalence, characteristics and factors associated with MRSA colonization on admission, and the cumulative incidence of colonization over the following 6 months.

Longitudinal and prospective study conducted over a 6-month period. All patients were screened at admission using nasal and ulcers swabs within the first 24h. Patients were screened also at the end of the study to assess carrier status.

The prevalence of MRSA colonization was 7.6% at the entry (25 patients). In the multivariate analysis, advanced age, recent use of antibiotics, prior colonization by MRSA, and peripheral vascular disease were independent risk factors for colonization at admission. With standard precautions, the 6-month cumulative incidence of MRSA colonization was 4.2%.

In our long-term care facility, MRSA colonization at the time of admission was frequent. Few patients were colonized during the study and no episodes of infection were reported. Probably, standard precautions, including hand washing and appropriate barrier procedures during the care of wounds, are the most useful control measures.