Impact of vancomycin resistance on mortality in neutropenic patients with enterococcal bloodstream infection: a retrospective study

Background: Vancomycin-resistant Enterococcus (VRE) bloodstream infection (BSI) is generally associated with the delayed administration of adequate antibiotics. The identification of risk factors and outcomes of VRE BSI is necessary for establishing strategies for managing neutropenic fever in patients with hematological malignancies. Methods: We retrospectively analysed consecutive cases of enterococcal BSI in patients with neutropenia after chemotherapy or stem cell transplantation between July 2009 and December 2011 at a single center. Results: During the 30-month period, among 1,587 neutropenic patients, the incidence rate of enterococcal BSI was 1.76 cases per 1,000 person-days. Of the 91 enterococcal BSIs, there were 24 cases of VRE. VRE BSI was associated with E. faecium infection (P < .001), prolonged hospitalization (P = .025) and delayed administration (= 48 hours after the febrile episode) of adequate antibiotics (P = .002). The attributable mortality was 17% and 9% for VRE and vancomycin-susceptible Enterococcus (VSE), respectively (P = .447). The 30-day crude mortality was 27% and 23% for VRE and VSE, respectively (OR 1.38, 95% CI 0.53-3.59; P = .059). Only SAPS-II was an independent predictive factor for death (adjusted OR 1.12, 95% CI 1.08-1.17; P < .001). Conclusions: In conclusion, vancomycin resistance showed some trend towards increasing 30-day mortality, but is not statistically significant despite the delayed use of adequate antibiotics (= 48 hours). Only underlying severity of medical condition predicts poor outcome in a relatively homogeneous group of neutropenic patients.