Risk Factors for Mortality Associated With Enterococcal Bloodstream Infections

Objective: To determine risk factors for mortality in patients with a nosocomial enterococcal primary bloodstream infection (EPBI) and to assess whether vancomycin resistance placed a patient at increased risk of death. Design/Setting: A retrospective cohort study was conducted in four National Nosocomial Infection Surveillance System hospitals. Results: Of 145 patients identified with EPBIs, 74 (51%) died, and 26 (18%) had a vancomycin-resistant isolate. Upon comparing patients with EPBIs who survived to those who died, no associations were found between mortality and prior invasive device use, procedure history, type or number of prior nosocomial infections, length of hospitalization before infection, or receipt of vancomycin. Independent predictors of mortality were indices of severity of illness (APACHE II score and comorbidity weighted index), age, the use of third-generation cephalosporins or metronidazole during the week prior to infection, and female gender. Conclusions: Vancomycin resistance was not an independent predictor of death, and its role was difficult to establish, because cohort patients were among the most severely ill of all hospitalized patients. Enterococcal primary bloodstream infections appear to indicate severe, life-threatening disease processes. The pathogenicity of enterococci and the role of vancomycin resistance as a cause of mortality in patients with EPBIs need to be assessed further.