Enterobacter species bacteremia:: Factors predictive of mortality at a tertiary care institution

The epidemiology and clinical features associated with mortality in patients with Enterobacter species bacteremia at a large tertiary care institution were investigated in a 10-year longitudinal analysis. The medical records of 134 adult patients with Enterobacter species bloodstream infections from 1986 to 1995 were reviewed. Malignancy (44%), immunosuppressive therapy (22.6%), chronic renal insufficiency (18%), and diabetes mellitus (19.4%) were significant comorbid illnesses in patients with Enterobacter species bacteremia. Enterobacter cloacae was the most common Enterobacter species isolated in blood cultures (57%). In 25% of the cases of Enterobacter species bacteremia, more than one organism was recovered. Although the majority of bloodstream infections were nosocomially acquired, 31% of the episodes of bacteremia were in patients admitted from the community. The gastrointestinal and genitourinary tracts were the most common sources of secondary bacteremia (60%). A central indwelling venous catheter was implicated as a source of the bloodstream infection in 22% of the cases. Mortality in this series of patients with Enterobacter species bacteremia was 26.9%. By multivariate analysis, age >65 years, intraabdominal source, and need for vasopressor support were each predictive of greater mortality. Surgical intervention or removal of indwelling catheters was strongly associated with improved survival. Resistance of the Enterobacter species blood isolates to third-generation cephalosporins and broad-spectrum penicillins remained constant at 7% throughout the study period. Antimicrobial resistance in this study was not statistically associated with increased mortality. As a distinct clinical entity, the occurrence and mortality associated with Enterobacter species bacteremia in patients at a tertiary care institution were associated with diminished host defenses and increased disease burden.