Whole-genome sequencing analysis reveals the spread of a vanB-carrying transposon among different vancomycin-resistant Enterococcus faecium clinical isolates in a non-endemic setting

Background Vancomycin-resistant enterococci (VRE), particularly Enterococcus faecium (VREfm), can cause serious nosocomial infections, and have been responsible for healthcare-associated outbreaks. Spreading of VREfm occur both clonally by the dissemination mobile genetic elements. Aim To report prospective analysis whole-genome sequencing (WGS) data, including core-genome multi-locus sequence typing (cgMLST) transposon analysis, during a vanB outbreak. Methods Screening vanB-positive isolates was performed real-time polymerase chain reaction (PCR) on an overnight enriched broth and, if positive, subculture performed. underwent WGS. Generated data were used molecular that cgMLST using SeqSphere. For characterization, mapped against reference Tn1549 CLC Genomics Workbench, or de-novo assemblies BLASTN comparisons. Results In total, 1358 PCRs Two hundred fifty-one specimens from 207 patients tested positive PCR vanB, which 13 obtained six identified as culture. These harboured seven unique belonging to four cluster types: CT118 (N=2), CT2483 (N=3), CT2500 (N=1) CT2501 (N=1). Transposon revealed presence identical vanB-carrying in cultured all could be linked based epidemiological data. Conclusion A outbreak occurred study hospital, with types. In-depth rather than clonal spread