Clinical and molecular epidemiology of an outbreak of infusion-related Acinetobacter baumannii bacteremia in an intensive care unit.

Objective: To describe the clinical and molecular epidemiology of an outbreak of infusion-related Acinetobacter baumannii bacteremia in an intensive care unit (ICU). Methods: Six cases of A. baumannii bacteremia identified in the Foligno Hospital ICU, Italy, were peer reviewed. Antibiotic susceptibility and genotyping (PFGE and RAPD) of A. baumannii isolates were carried out. Results: All A. baumannii blood isolates and a strain isolated from parenteral solution had an identical genotype. The strains were susceptible to carbapenems and the combination of meropenem plus amikacin or piperacillin/ tazobactam plus netilmicin was synergistic. A. baumannii bacteremia persisted for several days in almost all patients; catheter tip cultures were always positive for A. baumannii. Three patients, with an elevated Apache II score, died of sepsis. Conclusions: The outbreak was related to contaminated parenteral solutions improperly prepared in the ward. Aseptic preparation in the hospital pharmacy allowed for an interruption of the outbreak.