MRSA in the critically ill.

MRSA colonization and infection rates were prospectively examined over an 18 month period in a general Intensive Care Unit. Of 642 admissions, 305 were in ICU for longer than 48 h and were hence included and a further three patients were already colonized at admission but stayed less than 48 h. Ninety-seven patients were colonized with MRSA including 19 who were already colonized at admission. There were 56 episodes of clinical infection in 43 patients. The mortality rates in the colonized and infected groups, were 14.8% and 16.2% respectively, while the rate in those not colonized was 23%. These figures were not statistically different. Those colonized or infected with MRSA had significantly longer ICU stays than those not colonized. Sputum colonization and infection was a major site for MRSA. There was diagnostic certainty of MRSA infection in 40% of cases emphasizing the difficulty in diagnosis of infection due to MRSA in the critically ill. Both colonization and infection with MRSA are associated with longer ICU stay but do not appear to influence mortality. Copyright 2001 The Hospital Infection Society.