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Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance
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Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance

Published on: May 2, 2018

Evolution of microcin V and colicin Ia plasmids in Escherichia coli

Anne Jeziorowski1, David M Gordon

  • 1School of Botany & Zoology, The Australian National University, Canberra, ACT 0200 Australia.

Journal of Bacteriology
|July 24, 2007
PubMed

Insights

Escherichia coli strains show that colicin Ia and microcin V bacteriocins frequently co-occur on the same plasmid. This association has evolved multiple times, suggesting a selective advantage for these co-occurring bacteriocins.

Area of Science:

  • Microbiology
  • Genetics
  • Evolutionary Biology

Background:

  • Bacteriocins are antimicrobial peptides produced by bacteria.
  • Colicin Ia and microcin V are two types of bacteriocins produced by Escherichia coli.
  • The co-occurrence and genetic basis of bacteriocin production in bacterial strains are of interest for understanding microbial evolution and competition.

Purpose of the Study:

  • To investigate the association between colicin Ia and microcin V production in Escherichia coli strains.
  • To determine the genetic mechanisms underlying the co-occurrence of these bacteriocins.
  • To explore the evolutionary history of this association.

Main Methods:

  • Genotypic characterization of Escherichia coli strains.
  • Plasmid analysis to identify genes encoding bacteriocins.
  • Nucleotide variation analysis of bacteriocin genes and plasmid backbones.
  • Phylogenetic analysis to infer evolutionary history.

Main Results:

  • Colicin Ia and microcin V were found to co-associate in Escherichia coli strains more often than expected by chance.
  • When co-occurring, both bacteriocins are encoded on the same conjugative plasmid.
  • The distribution of these plasmids is nonrandom with respect to the host strain's genomic background.
  • Evidence suggests the association evolved on multiple occasions through the transfer of the microcin V operon and other genes onto specific colicin Ia plasmids.

Conclusions:

  • The co-occurrence of colicin Ia and microcin V in Escherichia coli is a nonrandom phenomenon driven by genetic association on plasmids.
  • The repeated evolution of this association suggests potential fitness benefits, although these have not yet been determined.
  • Understanding these associations provides insights into bacterial adaptation and the dynamics of horizontal gene transfer.

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