Acquisition of imipenem-resistant Acinetobacter baumannii in a pediatric intensive care unit:: a case-control study

Objective: To investigate the risk factors associated with nosocomial acquisition of imipenem-resistant Acinetobacter baumannii (IRAB) among pediatric intensive care patients. Abstract Design and setting: A retrospective case control study was conducted in a pediatric intensive care unit (PICU). Patients and participants: Cases were children in whom IRAB was isolated from any clinical specimen obtained at least 48 h following admission to PICU. Controls were children without IRAB matched to cases in 2:1 ratio. Twenty-six cases were matched with 52 controls according to the chronological order of admission. Measurements and results: Between July 2001 and December 2003, 52 (62%) of 84 clinical A. baumannii isolates were found nonsusceptible to imipenem (MIC >= 8 mu g/ml). Demographic variables, comorbid conditions, clinical picture at admission, invasive procedures, use of antimicrobials and other drugs were analyzed as potential risk factors. Use of carbapenems and other beta-lactams, aminoglycosides, ranitidine, mechanical ventilation, central venous or urinary catheters and length of stay in PICU were among the factors significantly associated with IRAB acquisition in the univariate analysis. By multivariate analysis, however, only aminoglycoside use and length of stay in the PICU were independent risk factors. Conclusions: Acquisition of IRAB by PICU patients was independently associated with aminoglycoside use and prolonged stay in the unit. Studies of evaluation of infection control policies need to be pursued.