Microbiological features and risk factors for acquiring multidrug-resistant Acinetobacter baumannii bacteremia in pediatric patients. Case-control study

Multidrug-resistant Acinetobacter baumannii (MAB) is an important nosocomial pathogen. To analyze the risk factors for acquiring MAB, and the clinical and microbiological characteristics of MAB bacteremia (MABB) in children. Control-case study 2005-2008. Demographic and clinical data from all MABB and from non-multiresistant gram-negative bacteremias were recorded. Identification at species level, antimicrobial susceptibility tests, time-kill studies and clonally relationships were performed. Stata 8.0 was used for data analysis. A total of 50 MABB and 100 controls were included. Ninety four percent of patients acquired MAB in ICU and the 88% had underlying diseases. All patients had invasive procedures previous to MABB. The median of hospitalization stay previous to MABB was different in cases than in controls (16 vs 7 days, p < 0.001). Five clones were detected among the MABB. Time-killing curves showed bactericidal activity of ampicillin/sulbactam plus gentamicin and polymixin B. Three patients with MAB died. In a multivariate analysis final predictors of MABB were: previous use of broad-spectrum antibiotics [OR: 7,0; IC 95% 1,93-25,0; p: 0,003] and mechanical ventilation [OR: 4,19; IC 95% 1,66-10,0; p: 0,002]. MABB were detected in patients with underlying conditions, invasive procedures and prolonged hospitalization. Predictors of MABB were mechanical previous use of broad-spectrum antibiotics and mechanical ventilation.