External sources of vancomycin-resistant enterococci for intensive care units

Objective: The incidence of colonization and infection with vancomycin-resistant enterococci (VRE) has increased dramatically in the last 5 yrs, especially in intensive care units (ICUs). We studied VRE-colonization in patients on admission to a medical ICU (MICU) where VRE colonization is endemic. Design: Prospective, descriptive analysis. Setting: An MICU of a public hospital. Patients: Three hundred and one consecutively admitted patients. Measurements and Main Results: Rectal swabs were obtained on admission from all patients. VRE isolates from all colonized patients were genetically fingerprinted by pulsed-field gel-electrophoresis (PFGE). Forty-three (14%) of 301 patients were colonized with VRE on MICU admission. Three (7%) of these 43 patients were admitted directly from the community without prior hospital contact, Risk of colonization on admission was related to the length of stay in the hospital before MICU-admission (odds ratio 4.65 for patients with a stay of at least 3 days) and previous in-hospital use of antibiotics, Of 22 VRE PFGE strain types recognized in the MICU during the study period, four (18%) were introduced by patients admitted directly from the community and ten (45%) were introduced by patients admitted from other hospital wards, Conclusions: These results show that although ICUs are considered epicenters for antibiotic resistance, sources extraneous to our MICU (e.g., other wards) contributed the majority of VRE strain types in the unit.