Cumulative incidence of vancomycin-resistant Enterococcus faecium detection by patient characteristics or possible exposures: prioritization of patients for active screening culture.

Background: The target population for active surveillance culture (ASC) of vancomycin-resistant Enterococcus species (VRE) by stool or rectal swabs has not been fully determined during VRE outbreaks in healthcare settings in non-VRE endemic situation.

Aim: To evaluate cumulative incidences of VRE detection during a vancomycin-resistant Enterococcus faecium outbreak to determine reasonable target populations for ASC.

Methods: Cases included inpatients whose first VRE-positive sample was obtained at Shizuoka General Hospital between February 2022 and January 2023, during which we conducted admission screening for possible high-risk patients, bi-weekly screening of all inpatients, admission and discharge screening in the high-care unit, and screening of contacts in each ward using stool or rectal samples. We calculated cumulative incidences of VRE detection for those screened by patient characteristics or possible exposure.

Findings: Among 60 cases identified, 55 (92%) were by ASC. Cumulative incidence was higher for contacts (6.4%, 15/234) than for those identified by other screening methods (0.5%, 40/8565). Among the patients identified through admission screening, those previously hospitalized in areas of reported VRE outbreaks had the highest cumulative incidence (6.6%, 5/78) followed by patients requiring toilet assistance (3.7%, 6/161). A bundle approach including ASC and prompt contact precautions by the hospital infection control team, local public health centre, and local and national infection control experts helped terminate the outbreak in seven months.

Conclusion: Patients with contacts, prior hospitalization in areas with known VRE outbreaks, and who need toilet assistance appear to be high-risk populations for VRE detection and are candidates for ASC.