Impact of inappropriate antimicrobial therapy on outcome in patients with hospital-acquired pneumonia caused by Acinetobacter baumannii

Objectives: The purpose of this study was to evaluate the impact of inappropriate antimicrobial therapy on the outcome of patients with hospital-acquired pneumonia (HAP) caused by Acinetobacter baumannii. Methods: All cases of HAP caused by A. baumannii from January 2000 to March 2006 at the Samsung Medical Center (Seoul, Korea) were analyzed retrospectively. Results: A total of 116 patients with clinically significant Acinetobacter HAP were enrolled. Among the A. baumannii isolates, 60.3% showed multi-drug resistance (MDR), 16.4% were found to have imipenem resistance, and 15.5% had pan-drug resistance (PDR). The mean APACHE II score of the patients was 22.3 ± 7.9. The overall in-hospital and pneumonia-related mortality rates were 47.4% and 37.9%, respectively. The univariate analysis showed that the factors associated with pneumonia-related mortality were: MDR, PDR, high APACHE II score, inappropriate empirical antimicrobial therapy, and inappropriate definitive antimicrobial treatment (All p < 0.05). Among these, a high APACHE II score and inappropriate definitive antimicrobial therapy were found to be independent factors associated with a high mortality, after adjustment for other variables. Conclusions: The appropriate definitive antimicrobial therapy should be provided in patients with HAP caused by A. baumannii.