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mcr-1 facilitated selection of high-level colistin-resistant mutants in Escherichia coli

H Zhang1, D Zhao1, J Quan1

  • 1Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, Zhejiang, China.

Clinical Microbiology and Infection : the Official Publication of the European Society of Clinical Microbiology and Infectious Diseases
|December 18, 2018
PubMed
Abstract

Insights

The mcr-1 gene, a cause of colistin resistance, was studied for its effect on high-level colistin resistance (HLCR) mutations. This gene facilitates HLCR mutant selection in Escherichia coli but not Klebsiella pneumoniae.

Area of Science:

  • Microbiology
  • Genetics
  • Antimicrobial Resistance

Background:

  • The emergence of plasmid-mediated colistin resistance, primarily through the mcr-1 gene, poses a significant global health threat.
  • Colistin is a critical last-resort antibiotic for treating multidrug-resistant Gram-negative bacterial infections.

Purpose of the Study:

  • To investigate the influence of the mcr-1 gene on the selection of high-level colistin resistance (HLCR) mutations.
  • To determine if mcr-1 impacts HLCR mutation rates in specific Gram-negative bacteria, Escherichia coli and Klebsiella pneumoniae.

Main Methods:

  • Detection of HLCR mutation rates in Enterobacteriaceae strains (E. coli and K. pneumoniae) with and without the mcr-1 gene.
  • Utilized sequencing, plasmid elimination experiments, and real-time quantitative PCR for detailed analysis of HLCR mutants.

Main Results:

  • The mcr-1 gene significantly increased mutation rates for high-level colistin resistance in Escherichia coli strains.
  • In contrast, the presence of the mcr-1 gene did not significantly affect the HLCR mutation rates in Klebsiella pneumoniae strains.

Conclusions:

  • The mcr-1 gene not only confers low-level colistin resistance but also actively facilitates the selection of high-level colistin resistance mutants in E. coli.
  • The mcr-1 gene's impact on HLCR selection differs between bacterial species, specifically not affecting K. pneumoniae.
Keywords:
Escherichia coliHigh-level colistin resistanceKlebsiella pneumoniaeMutation ratemcr-1

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