Abstract
Objectives: From 2012 to 2015, a sudden significant increase in vancomycin-resistant (vanA) Enterococcus faecium (VREfm) was observed in the Capital Region of Denmark. Clonal relatedness of VREfm and vancomycinsusceptible E. faecium(VSEfm) was investigated, transmission events between hospitals were identified and the pan-genome and plasmids from the largest VREfm clonal group were characterized. Methods: WGS of 1058 E. faecium isolates was carried out on the Illumina platform to perform SNP analysis and to identify the pan-genome. One isolate was also sequenced on the PacBio platform to close the genome. Epidemiological data were collected fromlaboratory information systems. Results: Phylogeny of 892 VREfm and 166 VSEfm revealed a polyclonal structure, with a single clonal group (ST80) accounting for 40% of the VREfm isolates. VREfm and VSEfm co-occurred within many clonal groups; however, no VSEfm were related to the dominant VREfm group. A similar vanA plasmid was identified in ≥99% of isolates belonging to the dominant group and 69% of the remaining VREfm. Ten plasmids were identified in the completed genome, and ∼29% of this genome consisted of dispensable accessory genes. The size of the pan-genome among isolates in the dominant group was 5905 genes. Conclusions: Most probably, VREfm emerged owing to importation of a successful VREfm clone which rapidly transmitted to the majority of hospitals in the region whilst simultaneously disseminating a vanA plasmid to preexisting VSEfm. Acquisition of a heterogeneous accessory genome may account for the success of this clone by facilitating adaptation to new environmental challenges.
Original language | English |
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Pages (from-to) | 1776-1785 |
Number of pages | 10 |
Journal | Journal of Antimicrobial Chemotherapy |
Volume | 74 |
Issue number | 7 |
DOIs | |
Publication status | Published - 1 Jul 2019 |
Bibliographical note
Funding Information:This work was supported by the Scandinavian Society for Antimicrobial Chemotherapy Foundation, the Danish Ministry of Health, The A. P. Møller foundation (Fonden til Laegevidenskabens Fremme) and internal funding.
Publisher Copyright:
© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.