Abstract
A nosocomial outbreak of vancomycin-resistant enterococcus (VRE) has occurred in a Yamanashi prefectural hospital in Japan. We investigated the outbreak to determine the risk factors for VRE infection and identify the routes of infection. A case was defined as a patient hospitalized from 1 January to 23 June 2004 with positive findings for VanB type VRE in any stool specimen. Stool specimens were collected from all inpatients and staff for VRE isolation. The strains of VRE were analyzed by pulsed-field gel electrophoresis (PFGE). Clinical and epidemiological information was collected by reviewing hospital records, staff interviews, and inspections. Twenty four cases (10 males, 14 female) were identified. All patients were asymptomatic. All strains isolated from the cases were identical with the PFGE pattern. The procedures for washing hands, changing diapers and cleaning the environment in the ward were inadequate to prevent transmission. A patient who touched the floors with his hands was strongly suspected to have acquired VRE from the floor contaminated with another VRE patient's stool. A case-control study was conducted among patients who were in the hospital from 1 April to 23 June 2004 to determine risk factors. The study revealed associations between antibiotic use within the past month and VRE infection (OR 8.91, 95% CI 1.1-72.8). We concluded that VRE was transmitted from infected patients to other patients through the hospital staff hands or clothing and the environment, including the floors. We recommended that the hospital separate the infected patients from the uninfected patients and improve procedures for washing hands, changing diapers and cleaning the ward, including the floors, if patients touch them directly. The hospital accepted these recommendations and the outbreak ended.
