Genomic analysis of 495 vancomycin-resistant Enterococcus faecium reveals broad dissemination of a vanA plasmid in more than 19 clones from Copenhagen, Denmark

TY - JOUR

T1 - Genomic analysis of 495 vancomycin-resistant Enterococcus faecium reveals broad dissemination of a vanA plasmid in more than 19 clones from Copenhagen, Denmark

AU - Pinholt, Mette

AU - Gumpert, Heidi

AU - Bayliss, Sion

AU - Nielsen, Jesper B

AU - Vorobieva, Veronika

AU - Pedersen, Michael

AU - Feil, Edward

AU - Worning, Peder

AU - Westh, Henrik

N1 - © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: [email protected].

PY - 2017/1

Y1 - 2017/1

N2 - OBJECTIVES: From 2012 to 2014, there has been a huge increase in vancomycin-resistant (vanA) Enterococcus faecium (VREfm) in Copenhagen, Denmark, with 602 patients infected or colonized with VREfm in 2014 compared with just 22 in 2012. The objective of this study was to describe the genetic epidemiology of VREfm to assess the contribution of clonal spread and horizontal transfer of the vanA transposon (Tn1546) and plasmid in the dissemination of VREfm in hospitals.METHODS: VREfm from Copenhagen, Denmark (2012-14) were whole-genome sequenced. The clonal structure was determined and the structure of Tn1546-like transposons was characterized. One VREfm isolate belonging to the largest clonal group was sequenced using long-read technology to close a 37 kb vanA plasmid.RESULTS: Phylogeny revealed a polyclonal structure where 495 VREfm isolates were divided into 13 main groups and 7 small groups. The majority of the isolates were located in three groups (n = 44, 100 and 218) and clonal spread of VREfm between wards and hospitals was identified. Five Tn1546-like transposon types were identified. A dominant truncated transposon (type 4, 92%) was spread across all but one VREfm group. The closed vanA plasmid was highly covered by reads from isolates containing the type 4 transposon.CONCLUSIONS: This study suggests that it was the dissemination of the type 4 Tn1546-like transposon and plasmid via horizontal transfer to multiple populations of E. faecium, followed by clonal spread of new VREfm clones, that contributed to the increase in and diversity of VREfm in Danish hospitals.

AB - OBJECTIVES: From 2012 to 2014, there has been a huge increase in vancomycin-resistant (vanA) Enterococcus faecium (VREfm) in Copenhagen, Denmark, with 602 patients infected or colonized with VREfm in 2014 compared with just 22 in 2012. The objective of this study was to describe the genetic epidemiology of VREfm to assess the contribution of clonal spread and horizontal transfer of the vanA transposon (Tn1546) and plasmid in the dissemination of VREfm in hospitals.METHODS: VREfm from Copenhagen, Denmark (2012-14) were whole-genome sequenced. The clonal structure was determined and the structure of Tn1546-like transposons was characterized. One VREfm isolate belonging to the largest clonal group was sequenced using long-read technology to close a 37 kb vanA plasmid.RESULTS: Phylogeny revealed a polyclonal structure where 495 VREfm isolates were divided into 13 main groups and 7 small groups. The majority of the isolates were located in three groups (n = 44, 100 and 218) and clonal spread of VREfm between wards and hospitals was identified. Five Tn1546-like transposon types were identified. A dominant truncated transposon (type 4, 92%) was spread across all but one VREfm group. The closed vanA plasmid was highly covered by reads from isolates containing the type 4 transposon.CONCLUSIONS: This study suggests that it was the dissemination of the type 4 Tn1546-like transposon and plasmid via horizontal transfer to multiple populations of E. faecium, followed by clonal spread of new VREfm clones, that contributed to the increase in and diversity of VREfm in Danish hospitals.

KW - Journal Article

U2 - 10.1093/jac/dkw360

DO - 10.1093/jac/dkw360

M3 - Journal article

C2 - 27605596

SN - 0305-7453

VL - 72

SP - 40

EP - 47

JO - The Journal of antimicrobial chemotherapy

JF - The Journal of antimicrobial chemotherapy

IS - 1

ER -