In:
Journal of Antimicrobial Chemotherapy, Oxford University Press (OUP), Vol. 75, No. 7 ( 2020-07-01), p. 1756-1765
Abstract:
To investigate the prevalence and transmission of mcr-3 among Salmonella enterica serotype Typhimurium and 1,4,[5],12:i:−. Methods A total of 4724 clinical Salmonella isolates were screened for the presence of mcr-3 in China during 2014–19. The clonal relationship of the mcr-3-positive isolates and their plasmid contents and complete sequence were also characterized based on WGS data from the Illumina and MinION platforms. Results We identified 10 mcr-3-positive isolates, and all were MDR, mostly resistant to colistin, cefotaxime, ciprofloxacin, doxycycline and florfenicol. mcr-3 was co-present with blaCTX-M-55-qnrS1 on hybrid ST3-IncC-FII conjugatable plasmids (n = 6) and an ST3-IncC non-conjugatable plasmid (n = 1) and embedded into a pCHL5009T-like IncFII plasmid on the Salmonella chromosome (n = 3). Four distinctive genetic contexts surrounded mcr-3 and all but one were closely related to each other and to the corresponding region of IncFII plasmid pCHL5009T. IS15DI was most likely the vehicle for integration of mcr-3-carrying IncFII plasmids into ST3-IncC plasmids and the chromosome and for shaping the MDR regions. In addition, a phylogenetic tree based on the core genome revealed a unique Salmonella lineage (≤665 SNPs) that contained these 10 mcr-3-positive isolates and another 38 (33 from patients) mcr-3-positive Salmonella from five countries. In particular, most of the 51 mcr-3-positive isolates belonged to ST34 and harboured diverse antibiotic resistance genes (ARGs), including mcr-3-blaCTX-M-55-qnrS1, and possessed similar ARG profiles. Conclusions Our findings revealed global clonal spread of MDR ST34 Salmonella from clinical isolates co-harbouring mcr-3 with blaCTX-M-55 and qnrS1 and a flexibility of mcr-3 co-transmittance with other ARGs mediated by mobile genetic elements.
Type of Medium:
Online Resource
ISSN:
0305-7453
,
1460-2091
Language:
English
Publisher:
Oxford University Press (OUP)
Publication Date:
2020
detail.hit.zdb_id:
1467478-6
detail.hit.zdb_id:
191709-2
SSG:
15,3
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