Patients exposed to vancomycin-resistant enterococci during in-hospital outbreaks in a low endemic setting: a proposal for risk-based screening.

Background: The optimal extent of screening of contact patients (CoPat) after exposure to patients infected or colonized with vancomycin-resistant enterococci (VRE) remains controversial.

Methods: We retrospectively developed a new risk stratification for screening patients exposed to VRE, based on data from three outbreaks-two with Enterococcus faecium vanB and one with Enterococcus faecium vanA involving 1096 CoPat-in a low endemic setting. We classified them into four risk groups: three on environmental exposure, one by healthcare exposure: high (sharing the same room/bathroom with a VRE-colonized patient), medium (hospitalization in the same room after a VRE-colonized patient's discharge until terminal disinfection including ultraviolet C (UVc)-disinfection), low (hospitalized in the same room within three weeks before the VRE-colonized patient), and "staff" (screening of patients having the same medical care team).

Results: VRE-transmission occurred in 7.9% in the high-risk group compared to 0.6% and 0% in the medium and low risk groups. There was a significant trend to higher rates of transmission by risk level of exposure (p < 0.001). In the "staff" group, VRE transmission rate was 2.3%.

Conclusion: Based on this stratification, we recommend to focus screening of exposed CoPat on the high-risk and "staff" group, saving resources and costs, but larger studies will allow to further improve the yield of VRE screening in the outbreak setting.