Risk factors for nosocomial Acinetobacter bacteremia: a case-control study of intensive care unit patients

Abstract

Objective: This study was performed to identify risk factors and to determine the attributable mortality and clinical outcomes of nosocomial Acinetobacter bacteremia in our intensive care unit. Methods: A retrospective case-control (1:1) study was conducted in a tertiary, academic hospital composed of 300 beds. The control group consisted of 54 consecutive patients with negative blood cultures, matched by sex, age (p10 years), primary and secondary diagnosis, operative procedures, and date of admission. Results: There was a trend for a longer median duration of hospitalization among the patient group compared with the control group (25.0 versus 8.0 days; p=0.001). Patients with Acinetobacter bacteremia had significantly more hemodynamic instability (hypoxia, shock) (p=0.001). We detected that the presence of risk factors such as mechanical ventilation, central venous catheter, anemia, thrombocytopenia, hypoalbuminemia and impairment in creatinine clearance was higher in the patient group than in the control group (p<0.004). Thirty-three (61.1%) of the cases died whereas 14 (25.9%) of the controls died (p=0.001). The attributable mortality was estimated as 35.2%. Of the 54 Acinetobacter isolates, 44 (81.5%) were resistant to two or more different antibiotic classes. Conclusion: In critically ill patients, Acinetobacter bacteremia is associated with a significantly increased mortality rate. Central venous catheter insertion, mechanical ventilation, long length of hospital stay and concomitant metabolic disease were risk factors for the presence of bacteremia.