Risk factors for mortality in patients with bloodstream infections caused by carbapenem-resistant Pseudomonas aeruginosa: clinical impact of bacterial virulence and strains on outcome.

The incidence of carbapenem-resistant Pseudomonas aeruginosa (CRPA) bacteremia has increased in recent years, and infections caused by CRPA result in higher mortality than those caused by susceptible strains. This study was performed to evaluate the risk factors for mortality and to study the impact of virulence factors and bacterial strains on clinical outcomes in patients with CRPA bacteremia. Data on 63 episodes of CRPA bacteremia that have occurred between January 1, 2007, and December 31, 2009, in a teaching hospital (2000 beds) in Seoul, Korea, were analyzed. The Acute Physiology and Chronic Health Evaluation II (APACHE II) score at the time of CRPA bacteremia and the capacity of CRPA to form biofilm were independent predictive factors for mortality in patients with CRPA bacteremia. In addition, the biofilm-forming ability and elastase activity of strains were correlated with APACHE II scores to measure the severity of disease and estimate predicted mortality in the patients.