Vancomycin-Resistant Enterococcus (VRE) Colonization Is Associated with a High Rate of Bacteremia and Early Mortality in Transplant/Leukemia Patients.

Background: Vancomycin-resistant enterococci (VRE) have become increasingly important nosocomial pathogens in very ill and immunocompromised hospitalized patients (pts). Due to an increase in VRE clinical cultures including bacteremias on our institutional transplant/leukemia service in early 2004, active surveillance for VRE among this population was instituted in June 2004. We describe here the incidence and prevalence of VRE colonization and infection in this population over a two year study period, as well as selected pt demographics and mortality associated with VRE bacteremia.

Methods: Between June 2004 and July 2006, active surveillance for VRE on inpatients on the transplant/leukemia service was performed by acquiring perirectal or stool swabs for VRE culture on hospital admission and on a weekly basis while inpatient. Acquisition of VRE was determined to be nosocomial if the initial culture was negative followed by a positive culture at any time during the hospital stay. Multiple sequential interventions as recommended by the Society for Healthcare and Epidemiology (SHEA) guidelines were implemented. Pt census data and daily isolation indicators were used to help determine VRE colonization rates and the prevalence of VRE on the units. Chart reviews were performed to obtain information on clinical pts related features and mortality of bacteremic pts.

Results: Nineteen percent (193/1019) of pts screened were colonized with VRE with the monthly nosocomial colonization rate ranging from 2–12% (rate/1000 patient days). Eighteen percent (31/189) of pts newly colonized with VRE became bacteremic, including 7/31 who had bacteremia as their primary presentation. Of the bacteremic pts, 24 (77.4%) died at a median of 20 days (range 2–208 days), 18 (75%) dying during their bacteremic hospitalization of multiple causes. Sixteen had acute leukemia, 11 non-Hodgkin’s lymphoma, and 3 other malignancies. Eighteen bacteremic pts had undergone allogeneic transplant & 5 autologous transplant. Fourteen of 18 allogeneic transplant pts had active GVHD and all 18 were on immune suppression therapy. Of all allogeneic transplants performed during the study period, 13% (18/140) were complicated by VRE bacteremia. Sixteen bacteremic pts required ICU stays, while 6 had C. difficile colitis and 5 mucositis during the same hospital stay. SHEA recommended interventions instituted at various times (e.g. enhanced contact and barrier precautions for colonized pts, “supercleans” of unit, written communication to staff, pts and families, gloving for all pt contacts) did not have a durable effect on these rates. However, the ratio of new nosocomial cases/overall prevalence of VRE in the units decreased 20% over the study period, suggesting some measure of control despite high colonization pressure. Assessment of response to intensive control strategies as well as delineation of risk factors for bacteremia and death in this population are ongoing and will be presented.

Conclusion: Despite application of standardized guidelines for VRE control, affecting a marked and durable decrease in endemic VRE colonization on a complicated transplant/leukemia service is difficult. VRE bacteremia following colonization in transplant/leukemia pts is common and is associated with early mortality. VRE control remains critical, and new modalities and approaches are essential.