[Infections caused by Acinetobacter spp. in critically ill ICU patients]

To determine the frequency of infections caused by Acinetobacter spp. in critically ill patients admitted to Spanish intensive care units (ICUs) and to assess the clinical features and outcome.

Prospective, observational, multicenter study. Patients admitted for one or two months to ICUs participating in the Spanish Nosocomial Surveillance Study (ENVIN project) between 1997 and 2003 were included. Patients were classified into the following groups: infected by Acinetobacter spp., infected by other pathogens, and uninfected.

In 343 (9.9%) patients from among 3,450 with nosocomial infection, Acinetobacter spp. was one of the pathogens identified in 406 episodes (cumulative incidence, 1.2 episodes per 100 patients). A. baumannii was the predominant species in 357 cases (87.9%). Variables significantly associated with selection of Acinetobacter spp. were medical (OR: 2.47; 95% CI: 1.24-4.91) or traumatic underlying disease (OR: 4.40; 95% CI: 2.20-8.80) and ICU stay (OR: 1.03; 95% CI: 1.02-1.04). The overall mortality rate in ICU patients with infection (31.1%) was similar to that of patients with Acinetobacter spp. infections (31.5%), although in both cases it was significantly higher than mortality in uninfected patients (10.7%). ICU mortality rates in patients with imipenem-resistant and imipenem-sensitive Acinetobacter spp. infections were not significantly different (33.3% vs. 30.0%; p = 0.7283).

Acinetobacter spp. were present in 9.9% of patients with ICU-acquired infection. There were no significant differences in ICU mortality rates between patients with Acinetobacter spp. infection and patients with infections caused by other microorganisms.