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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Microbiol. | doi: 10.3389/fmicb.2019.01994

Genome sequencing and characterization of five Escherichia coli co-expressing ESBL and MCR-1 resistance mechanisms, from different origins in China

 Pei Zhang1, 2,  JUAN WANG3,  Xinglong Wang3,  Zengqi Yang3*, Ruyi Dang3,  Jiangang Ma3, Yifei Xiong4, Xue Bai3,  Li Bai2* and  Séamus Fanning2, 5
  • 1Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Sun Yat-Sen University, China
  • 2China National Center for Food Safety Risk Assessment, China
  • 3College of Veterinary Medicine, Northwest A&F University, China
  • 4College of Food Science and Engineering, Northwest A&F University, China
  • 5School of Public Health, Physiotherapy and Sports Science, College of Health and Agricultural Sciences, University College Dublin, Ireland

In this study, we characterized five co-expressing ESBL and MCR-1 Escherichia coli recovered from food, food-producing animals and companion animals in China. Antimicrobial susceptibility tests, conjugation experiments, and plasmid typing were performed. Whole genome sequencing (WGS) was also undertaken for all five isolates using either PacBio RS II or Illumina HiSeq 2500 platforms. The cefotaxime and colistin resistance encoded by blaCTX-M and mcr-1 genes respectively was transferable by conjugation either together or separately for all five strains. Interestingly, the ESBL and mcr-1 genes could be co-selected by cefotaxime, while the colistin only selected the mcr-1-carrying plasmids during the conjugation experiments. Five E. coli sequence types were detected: ST88, ST93, ST602, ST162, and ST457. Although diverse plasmid profiles were identified, IncI2, IncFIB and IncFII plasmid types were predominant. These five clonally unrelated isolates harbored the mcr-1 gene located on similar plasmid backbones, which showed high nucleotide similarity to plasmid pHNSHP45. The mcr-1 gene can be disseminated via multiple mobile elements (with or without ISApl1) and be co-transmitted with blaCTX-M genes through IncI2 plasmids. Characterization of these co-existence ESBL and mcr-1 isolates extends our understanding on the dissemination of these resistance markers among bacteria of diverse origins.

Keywords: ESBL - Extended-spectrum beta-lactamase, MCR-1, conjugative plasmids (CP), Co-Occurrence, E. coli - Escherichia coli

Received: 11 Jun 2019; Accepted: 14 Aug 2019.

Copyright: © 2019 Zhang, WANG, Wang, Yang, Dang, Ma, Xiong, Bai, Bai and Fanning. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Mx. Zengqi Yang, College of Veterinary Medicine, Northwest A&F University, Xianyang, 712100, Shaanxi, China, yzq8162@163.com
Prof. Li Bai, China National Center for Food Safety Risk Assessment, Beijing, China, baili@cfsa.net.cn