Evaluation of risk factors for vancomycin-resistant Enterococcus bacteremia among previously colonized hematopoietic stem cell transplant patients

BackgroundHematopoietic stem cell transplantation (HSCT) recipients colonized with vancomycin-resistant Enterococcus (VRE) may have an increased risk of developing VRE bacteremia. Identification of risk factors for the development of subsequent VRE bacteremia among colonized HSCT recipients is necessary to predict which patients may benefit the most from receiving anti-VRE antibiotic therapy as part of an initial antimicrobial regimen when gram-positive bacteremia is suspected. MethodsThis study was a retrospective chart review conducted from May 2008 to May 2011. Adult HSCT patients admitted to the hospital found to have positive VRE surveillance cultures were included. A multivariate analysis was completed to identify risk factors for the development of VRE bacteremia in the study population. ResultsOf 152 patients, 19 (13%) patients developed subsequent VRE bacteremia. Risk factors identified for patients with current VRE colonization for VRE bacteremia were the utilization of vancomycin subsequent to VRE surveillance culture positivity (P=0.017), prolonged duration of neutropenia (P=0.001), immunosuppression (P<0.001), and timing of first VRE surveillance screen positivity at week 1 (P=0.005). A history of VRE colonization on a prior admission was not an independent risk factor for bacteremia in HSCT patients (P=1.0). HSCT patients with VRE bacteremia had a 30-day all-cause inpatient mortality rate of 29% (P=0.001). ConclusionHSCT patients receiving immunosuppressive therapy, who have been exposed to vancomycin subsequent to surveillance culture positivity, have had prolonged neutropenia of >30days, or first surveillance culture positive at week 1 of admission are potential candidates for early implementation of anti-VRE therapy when a gram-positive bacteremia is suspected.