Methicillin-resistant Staphylococcus aureus in long-term-care facilities.

Owing to a high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) among residents, long-term-care facilities (LTCFs) have become substantial reservoirs of this microorganism. Few data on the natural history of MRSA colonization in this setting are available. The cumulative incidence appears to be approximately 20% per year, and more than half of carriers have persistent colonization. Several host-related factors, such as antibiotic use, invasive devices, and poor infection control practices, increase the risk of colonization. Clinical experience suggests that subsequent MRSA infections are neither frequent nor severe while colonized residents are living in an LTCF; however, when admitted to an acute-care centre, colonized individuals may spread MRSA to other patients and may develop severe infections. Therefore, the epidemiological impact of the high prevalence of MRSA in these centres is more relevant than the clinical impact of this colonization for an individual resident. Standard precautions should be applied as routine infection control measures for all residents of LTCFs, whereas barrier precautions, cohorting, decolonization and other measures should be undertaken only for controlling outbreaks of MRSA infection.