Identification of a novel hybrid plasmid coproducing MCR-1 and MCR-3 variant from an Escherichia coli strain

Ruichao Li, Pei Zhang, Xiaorong Yang, Zhiqiang Wang, Séamus Fanning, Juan Wang, Pengcheng Du, Li Bai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Objectives: To characterize the genome of an Escherichia coli harbouring both mcr-1 and mcr-3.19 on a hybrid plasmid and the underlying transmission mechanisms. 

Methods: Broth microdilution was used to perform antimicrobial susceptibility testing. Conjugation assays and S1-PFGE were used to assess the transferability of mcr genes. Resistance genotypes and genetic contexts were investigated, based on WGS data from the Illumina and MinION platforms. Inverse PCR was performed to test the mcr-3.19-bearing circular intermediate. Bioinformatic tools were used to further characterize the hybrid plasmid. 

Results: E. coli CP53 was identified as harbouring both mcr-1 and mcr-3.19 on a 231 859 bp hybrid plasmid pCP53-mcr1-3 containing IncFIA, IncHI1A, IncHI1B and IncN replicons. The genetic structures of mcr-1 and mcr-3.19 were similar to those reported in other mcr-1 and mcr-3.19-bearing plasmids, which suggested that recombination between mcr-bearing plasmids had been mediated by ISs. However, the MDR plasmid pCP53-mcr1-3 cannot transfer via conjugation. Furthermore, another three plasmids were identified in the isolate, two of which encoded resistance genes. In640 duplication between two MDR plasmids was observed. An MDR-region recombination existed in E. coli CP53. A core structure consisting of mcr-3-dgkA existed in mcr-3-bearing plasmids reported, to date. Circular intermediates were observed for mcr-1 and mcr-3.19 regions. 

Conclusions: A novel mcr-3.19 was identified along with mcr-1 contained in a hybrid plasmid. This finding suggested that evolution of mcr genes among various plasmids was being driven by mobile elements. Molecular surveillance of mcr gene co-occurrence warrants further investigation to evaluate the public health risk.

Original languageEnglish
Pages (from-to)1517-1520
Number of pages4
JournalJournal of Antimicrobial Chemotherapy
Issue number6
Early online date21 Feb 2019
Publication statusPublished - 01 Jun 2019
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by the National Natural Science Foundation of China (31872523 and 31871899), the Natural Science Foundation of Jiangsu Province (BK20180900) and a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).

Publisher Copyright:
© 2019 The Author(s) 2019.

ASJC Scopus subject areas

  • Pharmacology
  • Microbiology (medical)
  • Infectious Diseases
  • Pharmacology (medical)


Dive into the research topics of 'Identification of a novel hybrid plasmid coproducing MCR-1 and MCR-3 variant from an Escherichia coli strain'. Together they form a unique fingerprint.

Cite this