Genetic background of Escherichia coli and extended-spectrum beta-lactamase type

Emerg Infect Dis. 2005 Jan;11(1):54-61. doi: 10.3201/eid1101.040257.


To assess the implication of the genetic background of Escherichia coli strains in the emergence of extended-spectrum-Beta -lactamases (ESBL), 55 TEM-, 52 CTX-M-, and 22 SHV-type ESBL-producing clinical isolates involved in various extraintestinal infections or colonization were studied in terms of phylogenetic group, virulence factor (VF) content (pap, sfa/foc, hly, and aer genes), and fluoroquinolone resistance. A factorial analysis of correspondence showed that SHV type, and to a lesser extent TEM type, were preferentially observed in B2 phylogenetic group strains that exhibited numerous VFs but were fluoroquinolone-susceptible, whereas the newly emerged CTX-M type was associated with the D phylogenetic group strains that lacked VF but were fluoroquinolone-resistant. Thus, the emergence of ESBL-producing E. coli seems to be the result of complex interactions between the type of ESBL, genetic background of the strain, and selective pressures in ecologic niches.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Ciprofloxacin / pharmacology
  • Communicable Diseases, Emerging / microbiology*
  • Drug Resistance, Bacterial*
  • Escherichia coli / drug effects
  • Escherichia coli / enzymology
  • Escherichia coli / genetics*
  • Escherichia coli / pathogenicity*
  • Escherichia coli Infections / microbiology
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Fluoroquinolones / pharmacology
  • Humans
  • Microbial Sensitivity Tests
  • Phylogeny*
  • Polymerase Chain Reaction
  • Virulence
  • Virulence Factors / genetics
  • Virulence Factors / metabolism
  • beta-Lactamases / classification*
  • beta-Lactamases / genetics
  • beta-Lactamases / metabolism


  • Anti-Bacterial Agents
  • Escherichia coli Proteins
  • Fluoroquinolones
  • Virulence Factors
  • Ciprofloxacin
  • beta-Lactamases