Methicillin-resistant Staphylococcus aureus in nursing homes. Epidemiology, prevention and management

Infections caused by Staphylococcus aureus are a significant cause of morbidity and mortality in elderly persons in the community, hospitals and chronic care facilities. Methicillin-resistant S. aureus (MRSA) has become an important cause of severe infection in acutely ill patients in hospitals from diverse geographic areas. Whether MRSA has the same potential to spread and cause infection in nursing homes has only recently been explored. In the facilities studied, asymptomatic MRSA carriage has been common, but patients do not appear to have the same risk of acquiring the organism. The risk of MRSA colonisation appears to be associated with increasing debility, the presence of invasive devices or wounds, and increased overall mortality. Most nursing home residents acquire MRSA during a hospital stay, not in the nursing home. Transmission of MRSA between nursing home residents may be less efficient than that seen among hospitalised patients. Once residents acquire MRSA, they remain persistently colonised for months to years. Many different MRSA strains circulate within nursing homes, probably reflecting the strains found in referring hospitals. Fortunately, although MRSA colonisation is relatively common, rates of MRSA infection and attributable mortality appear to be low. However, the presence of MRSA in a facility might lead to fewer treatment options when infections do occur, with more adverse effects and increased costs. The routine use of surveillance cultures and antibacterials in an attempt to permanently eradicate MRSA from nursing home residents has not been successful, and resistance has quickly emerged. More importantly, nursing homes should utilise infection control practices that disrupt transmission by direct contact, thus preventing the potential spread of MRSA. Simple, inexpensive precautions, which emphasise handwashing and the use of gloves and gowns when soiling by patient body fluids is likely, are generally effective. Knowledge of the patient's MRSA colonisation status is not necessary when these universal barrier precautions are applied to the care of all patients. If an increase in the rate of MRSA infections is documented, more intensive infection control measures should be implemented.