Centralised WGS for regional VRE surveillance

Objective: Whole genome sequencing (WGS) is increasingly being used to guide infection prevention and control measures. However, the value of regional prospective WGS surveillance for vancomycin-resistant Enterococcus faecium (VREfm) remains uncertain. The objective of this study is to investigate the value of routine centralised multicentre WGS in regional outbreak detection and analysis of transmission of VREfm within and between healthcare facilities. Methods VREfm isolates identified from patient samples in five different hospitals in the Netherlands during a one-year period were whole genome sequenced and typed using core genome multilocus sequence typing (cgMLST). Sequence data were correlated with admission data of the year prior to the first positive VREfm culture of the respective patients. By combining epidemiological and sequence data within and between hospital transmission events were identified. Results 57 VREfm isolates were detected during the study period. 38/57 (66.7%) isolates clustered with at least one other isolate. Based on our definitions, intrahospital transmission could be demonstrated in 37 of 38 cases and interhospital transmission in 3 of 38 cases. Using this approach, a multicenter outbreak and two local outbreaks were detected. Conclusions Routine whole genome sequencing of VRE is a powerful tool for detecting, tracing and delineating outbreaks. When integrated into a centralised surveillance system spanning collaborative healthcare networks, it becomes an essential tool for unravelling the complex transmission dynamics of VRE within and between hospitals, ultimately strengthening infection control strategies.