1255. First Outbreak Due to Vancomycin-Resistant Enterococcus Epidemic Clone ST796 in Europe

Abstract

BackgroundA large outbreak with different clones of vancomycin-resistant enterococci (VRE) affected the Bern University Hospital group for several months. The aim of this study was to describe the extent of the outbreak, using whole-genome sequencing (WGS).MethodsTriggered by two cases of VRE bloodstream infections on our hemato-oncology ward, an outbreak investigation was started. Microbiological diagnosis of VRE was obtained by culture and PCR. Epidemiological links were assessed by meticulous chart review and supplemented with WGS analyses. Multiple infection control measures were implemented to avoid further transmissions.ResultsBetween December 2017 and April 2018, 2,877 screening samples were obtained from 1,200 patients. Three out of six hospitals within the Bern University Hospital group were affected. Eighty-three patients (6.9%) were colonized with VR Enterococcus faecium. Of those, 76 (91.6%) had a strain carrying vanB, with 70 (84%) isolates virtually identical (separated by up to two alleles) by cgMLST and identified as MLST type ST796 (figure). The remaining seven patients (8.4%) were colonized with vanA carrying strains from five different STs. Five patients (7%) developed an invasive infection with VRE ST796. Temporo-spatial links were found in most patients carrying the outbreak strain. In order to control the outbreak, extensive infection control measures were implemented. By April 2018 the outbreak was contained with these specific measures.ConclusionThis VRE outbreak was characterized by a rapid intra- and inter-institutional spread of the emergent clone ST796. This clone was recently described in Australia and New Zealand but never before in Europe.1,2 A multi-faceted infection control led to the containment of the outbreak.