Enterococcal bacteremia is associated with increased risk of mortality in recipients of allogeneic hematopoietic stem cell transplantation

Background. Enterococci are an important cause of healthcare-associated infections. We retrospectively analyzed risk factors and outcome of vancomycin-resistant enterococci (VRE) and vancomycin-sensitive enterococci (VSE) infections.Methods.Seven hundred fifty-two patients who received hematopoietic stem cell transplants from 2004 through 2008 at the University of Minnesota were included.Results.Ninety-three patients had enterococcal bloodstream infection (BSI) during the first year after transplant. Vancomycin resistance was observed in 66 and 31 of isolates in adults and children, respectively. Cumulative incidence of VRE and VSE bacteremia was 6.6 (95 confidence interval [CI], 4.8-8.4) and 5.7 (95 CI, 4.0-7.4), respectively. Colonization with VRE before or after transplant was a risk factor for VRE bacteremia (odds ratio [OR], 3.3 [95 CI, 1.3-8.3] and 7.0 [95 CI, 4.0-14.8], respectively). Delay in engraftment increased the incidence of VRE bacteremia from 4.5 (95 CI, 2.9-6.6) if engrafted before day 21 and to 15 (95 CI, 3.2-38) if engrafted between days 36 and 42. In adults, mortality 30 days after infection was 38 for both VRE (95 CI, 25-54) and VSE cases (95 CI, 21-62). The hazard ratio for all-cause mortality up to 1 year after transplant was 4.2 (95 CI, 3.1-6.9) and 2.7 (95 CI, 1.4-5.1) for patients with VRE and VSE BSIs, respectively, compared to patients without enterococcal BSI. In pediatric patients, mortality 30 days after VRE and VSE bacteremia was 20 (95 CI, 5.4-59) and 4.5 (95 CI,. 6-28), respectively.Conclusion.High rates of vancomycin resistance and association of enterococcal infections with significant mortality warrant further efforts to optimize prevention and management of these infections.