NOSOCOMIAL ACQUISITION OF MULTIRESISTANT ACINETOBACTER-BAUMANNII - RISK-FACTORS AND PROGNOSIS

To identify risk factors for and prognostic indicators of the nosocomial acquisition of multiresistant Acinetobacter baumannii in an intensive care unit, we prospectively studied 40 patients: 13 who were infected with this organism and 27 who were colonized. Isolates were identified by pulsed-field gel electrophoresis; the infected/colonized patients were compared with 348 noninfected, noncolonized patients by logistic regression analysis and with matched historical controls in a cohort study. The severity of illness (evaluated by the APACHE II score; P <.05) and previous infection (P <.001) were retained as independent risk factors for acquiring A. baumannii. Logistic regression analysis selected a high APACHE II score (P <.0.1) and the acquisition of A. baumannii (P <.01) as factors independently associated with death. The acquisition of A. baumannii was associated not only with high mortality but also with a length of stay on the intensive care unit in excess of that due to the underlying disease alone; specifically, the attributable mortality was 25%, with a risk ratio for death of 2.0 (95% confidence interval, 1.11-3.62), and the duration of stay for infected/colonized patients was 10.3 days longer than that for controls (P <.001).