Risk factors for Acinetobacter baumannii nosocomial bacteremia in critically ill patients: a cohort study.

Nosocomial bacteremia caused by Acinetobacter baumannii (AB) is of increasing concern in critically ill patients, and the risk factors for this infection are not well established. An inception cohort study in a 40-bed medical and surgical intensive care unit (ICU) at a single institution was conducted during a 2-year period to determine the risk factors for AB nosocomial bacteremia. Risk factors related to the underlying diseases, the clinical picture at admission, and those acquired during the stay in the ICU were recorded upon admission and daily throughout the ICU stay. We defined an "invasive procedures index" as the number of invasive procedures performed every day during the ICU stay before the onset of AB bacteremia divided by the number of days in the ICU before the onset of AB bacteremia. Risk factors that were independently associated with AB bacteremia were immunosuppression, unscheduled admission to the hospital, respiratory failure at ICU admission, previous antimicrobial therapy, previous sepsis in the ICU, and the invasive procedures index.