Molecular characterization of a multidrug resistance IncF plasmid from the globally disseminated Escherichia coli ST131 clone

PLoS One. 2015 Apr 15;10(4):e0122369. doi: 10.1371/journal.pone.0122369. eCollection 2015.


Escherichia coli sequence type 131 (E. coli ST131) is a recently emerged and globally disseminated multidrug resistant clone associated with urinary tract and bloodstream infections. Plasmids represent a major vehicle for the carriage of antibiotic resistance genes in E. coli ST131. In this study, we determined the complete sequence and performed a comprehensive annotation of pEC958, an IncF plasmid from the E. coli ST131 reference strain EC958. Plasmid pEC958 is 135.6 kb in size, harbours two replicons (RepFIA and RepFII) and contains 12 antibiotic resistance genes (including the blaCTX-M-15 gene). We also carried out hyper-saturated transposon mutagenesis and multiplexed transposon directed insertion-site sequencing (TraDIS) to investigate the biology of pEC958. TraDIS data showed that while only the RepFII replicon was required for pEC958 replication, the RepFIA replicon contains genes essential for its partitioning. Thus, our data provides direct evidence that the RepFIA and RepFII replicons in pEC958 cooperate to ensure their stable inheritance. The gene encoding the antitoxin component (ccdA) of the post-segregational killing system CcdAB was also protected from mutagenesis, demonstrating this system is active. Sequence comparison with a global collection of ST131 strains suggest that IncF represents the most common type of plasmid in this clone, and underscores the need to understand its evolution and contribution to the spread of antibiotic resistance genes in E. coli ST131.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • DNA Transposable Elements / genetics
  • Drug Resistance, Multiple, Bacterial / genetics*
  • Escherichia coli / genetics*
  • Escherichia coli / pathogenicity
  • Escherichia coli Infections / drug therapy
  • Escherichia coli Infections / genetics*
  • Escherichia coli Infections / microbiology
  • Genome, Bacterial / drug effects
  • Humans
  • Mutagenesis
  • Plasmids / genetics*
  • Replicon / genetics
  • Sequence Analysis, DNA
  • beta-Lactamases / genetics


  • DNA Transposable Elements
  • beta-Lactamases

Grants and funding

This work was supported by grants from the Australian National Health and Medical Research Council (NHMRC) ( to MAS and SAB (APP1012076 and APP1067455). MAS is supported by an Australian Research Council ( Future Fellowship (FT100100662). SAB is supported by an NHMRC Career Development Fellowship (APP1090456). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.