Genomic diversity of mcr-carrying plasmids and the role of type IV secretion systems in IncI2 plasmids conjugation

Related Experiment Video

Updated: May 24, 2025

High-Resolution Comparison of Bacterial Conjugation Frequencies
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High-Resolution Comparison of Bacterial Conjugation Frequencies

Published on: January 10, 2019

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Zhe Li1, Zhenpeng Li1, Yao Peng1

  • 1National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.

Communications Biology
|March 2, 2025
PubMed

Insights

Colistin resistance plasmids spread rapidly, with IncI2 plasmids being the main type. Understanding their transfer mechanisms, particularly the Type IV Secretion System (T4SS), is key to controlling the spread of antimicrobial resistance.

Area of Science:

  • Microbiology
  • Genomics
  • Molecular Biology

Background:

  • Colistin resistance plasmids (pMCRs) are a growing public health threat due to rapid dissemination.
  • IncI2 plasmids are the primary epidemic type, often co-carrying multidrug resistance genes.

Purpose of the Study:

  • To investigate the genomic diversity and conjugation mechanisms of pMCRs.
  • To elucidate the role of Type IV Secretion Systems (T4SS) in IncI2 plasmid transfer.

Main Methods:

  • Analysis of 868 complete plasmid sequences.
  • Identification and characterization of T4SS components in pMCRs.
  • Conjugation assays and in vivo competitive assays in Escherichia coli.

Main Results:

  • IncI2 plasmids are the predominant epidemic type of pMCRs.
  • T4SS, specifically the VirB/D4 type, is present in 89.9% of pMCRs and crucial for conjugation.
  • VirB2 and VirB5 subunits play essential roles in plasmid transfer, with potential drug targets identified in VirB5.

Conclusions:

  • The VirB/D4 T4SS is a conserved and essential system for IncI2 plasmid dissemination.
  • Understanding the structural and co-evolutionary dynamics of T4SS components can inform strategies to curb the spread of colistin resistance.

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