Investigation of an outbreak of vancomycin-resistant Enterococcus faecium in a low prevalence university hospital

Background: Until 1995, there were no cases of vancomycin resistant enteroc occus (VRE) identified at our university hospital. From May 1995 to August 1996, we investigated a cluster of 10 cases of phenotypic class Van B Enter ococcus faecium. Methods: Patients were matched with controls who were on the same unit for at least 7 days prior to the case developing VRE, Control patients were age and sex matched if possible, and had duration of hospitalization at least as long as the number of days it took the patient to become VRE positive. W e analyzed 16 independent risk factors using Epi-info version 6, Environmen tal cultures were obtained in the MICU where 5 of the patients were located . All 10 patient isolates and environmental isolates were analyzed by pulse d field gel electrophoresis (PFGE), Results: PFGE confirmed the genetic relatedness of all 10 patient isolates and environmental isolates. The VRE-positive group was more likely to be im munosuppressed and to have exposure to 3 physicians. In the MICU, significa nt, P<0.05) risk factors for VRE were higher Apache scores, location adjace nt to a VRE case, duration of vancomycin and aminoglycoside use, duration o f invasive catheter use, and diarrhea, Among the VRE-positive environmental cultures was a blood pressure cuff wash that was used on several patients. Conclusion: We hypothesize that a VRE strain,vas introduced into our hospit al environment and was spread by personnel or contaminated equipment. As a consequence of this study, a hospital-wide VRE policy was implemented.