Bacteremias due to Citrobacter diversus and Citrobacter freundii. Incidence, risk factors, and clinical outcome

From 1974 to 1982, 38 patients developed Citrobacter bacteremia at two adult community-teaching hospitals in the Detroit Medical Center (incidence, 1.2 cases per 10,000 discharges). Citrobacter accounted for 0.7% of all bacteremias during the study period. Of 31 cases reviewed, Citrobacter bacteremia frequently developed in elderly patients (65%) and was hospital acquired (77%). Initial sites of infection included the urinary tract (39%), gastrointestinal tract (27%), wound (10%), and unknown (13%). More bacteremias caused by Citrobacter diversus tended to arise from the urinary tract, while patients with Citrobacter freundii bacteremia had significantly more gallbladder disease. Patients with Citrobacter bacteremia were more likely than patients with Escherichia coli bacteremia to have had additional pathogens in the bloodstream, to develop bacteremia in the hospital, and to have undergone invasive procedures contributing to infection. Significant differences were not observed in demographic, host, or other epidemiologic or clinical factors examined. Of patients with Citrobacter bacteremia, 48% died.