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Detection of Horizontal Gene Transfer Mediated by Natural Conjugative Plasmids in E. coli
06:56

Detection of Horizontal Gene Transfer Mediated by Natural Conjugative Plasmids in E. coli

Published on: March 24, 2023

Molecular structure and evolution of the conjugative multiresistance plasmid pRE25 of Enterococcus faecalis isolated

Michael Teuber1, Franziska Schwarz, Vincent Perreten

  • 1Laboratory of Food Microbiology, ETH Zurich, Zurich CH-8092, Switzerland. teuber@ilw.agrl.ethz.ch

International Journal of Food Microbiology
|November 5, 2003
PubMed

Insights

The largest sequenced enterococcal plasmid, pRE25, transfers multiple antibiotic resistances via conjugation. This study reveals its genetic makeup and its role in inter-bacterial communication within the gut microbiome.

Area of Science:

  • Molecular Biology
  • Microbiology
  • Genetics

Background:

  • Enterococci are significant in human and animal microbiomes, and their plasmids can carry antibiotic resistance genes.
  • Conjugative plasmids facilitate the transfer of genetic material, including resistance determinants, between bacteria.
  • Understanding plasmid structure and function is crucial for combating antibiotic resistance.

Purpose of the Study:

  • To characterize the novel conjugative multiresistance plasmid pRE25 from Enterococcus faecalis.
  • To determine the genetic basis of antibiotic resistance conferred by pRE25.
  • To investigate the role of pRE25 in inter-species bacterial communication.

Main Methods:

  • Conjugation experiments were performed in vitro using Enterococcus faecalis JH2-2, Lactococcus lactis Bu2, and Listeria innocua L19.
  • Nucleotide sequencing of the 50,237 base pair plasmid pRE25 was conducted.
  • Analysis of resistance genes and genes involved in conjugative transfer was performed.

Main Results:

  • Plasmid pRE25 successfully transferred resistances to kanamycin, neomycin, streptomycin, clindamycin, lincomycin, azithromycin, clarithromycin, erythromycin, roxithromycin, tylosin, chloramphenicol, and nourseothricin sulfate.
  • pRE25 contains genes for chloramphenicol acetyltransferase (cat) and 23S ribosomal RNA methyl transferase (ermB), identical to those in plasmid pIP501.
  • Aminoglycoside resistance genes are tandemly arranged, similar to transposon Tn5405, and pRE25 shares a large segment with pIP501, linked by insertion elements.

Conclusions:

  • pRE25 is the largest fully sequenced conjugative multiresistance plasmid identified in enterococci to date.
  • The plasmid harbors resistance genes also found in various pathogenic bacteria, highlighting potential for spread.
  • pRE25 demonstrates that enterococci from fermented foods actively participate in molecular communication across bacterial communities.

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