Vancomycin-Resistant Enterococcus in Hematology-Oncology Patients: a Review on Colonization, Screening, Infections, Resistance, and Antimicrobial Stewardship

Abstract

Vancomycin-resistant enterococcus (VRE) has emerged as a pathogen causing significant morbidity and mortality in immunocompromised patients in past decades. This article summarizes current literature on the epidemiology of VRE in hematology-oncology patients. It examines the associations between infection control practices, prescribing behavior, colonization, and infections due to VRE in patients with acute leukemia and stem cell transplant recipients. It also explores opportunities for antimicrobial stewardship and future research. VRE colonization is associated with VRE infections, but the progression from colonization to infection is not well defined. Colonization pressure may be associated with infection control practices at the patient unit level. Although previous data showed that environmental control may reduce the risk of VRE colonization in hematology-oncology patients, recent changes in contact precautions policies in some institutions could be associated with increased colonization pressure. Risk factors for VRE infections, particularly bacteremia, include exposure to broad-spectrum antibiotics, such as carbapenems, and neutropenia. Routine empiric use of anti-VRE antibiotics has not been shown to improve clinical outcomes, and itself could be a driver for VRE resistance. The majority of existing data are limited to single-centered, retrospective cohort studies, with before-and-after design being the most common. Without appropriate comparator groups, the results are subject to bias. Prospectively collected data with appropriate control groups will improve our understanding of the contributing factors to VRE infections, and the role antimicrobial stewardship plays.