RISK-FACTORS FOR NOSOCOMIAL BACTEREMIA DUE TO METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS

In a prospective surveillance study (February 1990-December 1991) perf ormed at a 1000-bed teaching hospital to identify risk factors for nos ocomial methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, 309 patients were found to be colonized (n = 103; 33 %) or infected ( n = 206; 67 %) by MRSA. Sixty-three of them developed bacteremia. Comp ared with 114 patients who had nosocomial bacteremia caused by methici llin-sensitive Staphylococcus aureus during the same period of time, M RSA bacteremic patients had more severe underlying diseases (p < 0.01) , were more often in intensive care units (p < 0.01) and had received prior antibiotic therapy more frequently (p < 0.01). To further identi fy risk factors for MRSA bacteremia, univariate and multivariate analy ses of this series of 309 patients were performed using the occurrence of MRSA bacteremia as the dependent variable. Among 14 variables anal yzed, intravascular catheterization, defined as one or more intravascu lar catheters in place for more than 48 h, was the only variable selec ted by a logistic regression model as an independent risk factor (OR = 2.7, CI = 1.1-6.6). The results of this study reinforce the concept t hat recent antibiotic therapy may predispose patients to MRSA infectio n and suggest that among patients colonized or infected by MRSA, those with intravascular catheters are at high risk of developing MRSA bact eremia.