Identification of a Novel Plasmid Carrying mcr-4.3 in an Acinetobacter baumannii Strain in China

Antimicrob Agents Chemother. 2019 May 24;63(6):e00133-19. doi: 10.1128/AAC.00133-19. Print 2019 Jun.

Abstract

Here, we identified mcr-4.3 in Acinetobacter baumannii, which had not been previously observed to carry an mcr gene. The mcr-4.3-harboring A. baumannii strain AB18PR065 was isolated from pig feces from a slaughterhouse in Guangdong Province of China. The mcr-4.3-carrying pAB18PR065 is 25,602 bp in size and could not be transferred in conjugation, transformation, and electroporation experiments, as we did not find any conjugation-related genes therein. pAB18PR065 harbors two copies of type II toxin-antitoxin systems, which are functional in plasmid stabilization and maintenance. pAB18PR065 shares similarity only with one recently identified plasmid, pAb-MCR4.3 (35,502 bp), from a clinical A. baumannii strain. It is likely that the emergence of pAb-MCR4.3 was due to the insertion of an 11,386-bp, ISAba19-based, composite transposon into pAB18PR065. These data indicate that mcr-4.3 was captured by an A. baumannii-original plasmid via horizontal gene transfer.

Keywords: Acinetobacter baumannii; colistin resistance; mcr-4.3.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acinetobacter Infections / microbiology*
  • Acinetobacter baumannii / drug effects
  • Acinetobacter baumannii / enzymology
  • Acinetobacter baumannii / genetics*
  • Acinetobacter baumannii / isolation & purification
  • Animals
  • Anti-Bacterial Agents / pharmacology*
  • China
  • Colistin / pharmacology*
  • Drug Resistance, Bacterial / genetics*
  • Feces / microbiology
  • Gene Transfer, Horizontal
  • Microbial Sensitivity Tests
  • Plasmids / genetics
  • Swine
  • Swine Diseases / microbiology*

Substances

  • Anti-Bacterial Agents
  • Colistin