THE EPIDEMIOLOGY OF METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS COLONIZATION AND INFECTION

Methicillin-resistant Staphylococcus aureus (MRSA) is an increasingly common nosocomial pathogen in health care facilities throughout the wo rld. Overall, approximately two-thirds of nosocomial cases and outbrea ks have occurred in critical care units. Major risk factors for coloni sation and infection in nursing homes include age, underlying conditio ns, nasal colonisation and the presence of indwelling devices such as catheters, tracheostomies and nasogastric tubes. In general, patients with MRSA infections in an acute care facility are more likely to have had a prolonged hospital stay, to have received prior antibiotics and to have severe underlying disease, than patients infected with methic illin-susceptible S. aureus. Risk factors for MRSA bacteraemia include : a higher frequency of severe underlying disease, poorer underlying p rognosis, prior antibiotic therapy, prolonged hospitalisation, intrava scular catheterisation, and intensive care unit location. Risk factors for developing MRSA postoperative wound infections include: prior ant imicrobial therapy, prolonged hospitalisation and severity of underlyi ng disease. Little data are available to identify specific risk factor s for colonisation or infection of burn wounds by MRSA.