Predominance and genetic diversity of community- and hospital-acquired CTX-M extended-spectrum beta-lactamases in York, UK

J Antimicrob Chemother. 2004 Sep;54(3):628-33. doi: 10.1093/jac/dkh397. Epub 2004 Aug 4.


Objectives: This study was conducted to detect the presence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae within the faecal flora of both community- and hospital-based patients in York and to characterize the bla(TEM), bla(SHV) and bla(CTX-M) genes present in these isolates.

Methods: One thousand faeces samples were collected and screened at York Hospital during October-December 2003. Ninety-five non-duplicate Enterobacteriaceae isolates resistant to third-generation cephalosporins were recovered; 22 isolates were selected for further study on the basis of a positive double disc diffusion test for ESBL production. Antibiotic susceptibility testing was performed to a range of antibiotics. The TEM, SHV and CTX-M genes were detected by PCR and the DNA sequenced.

Results: The distribution of ESBL-positive isolates from the hospital and community was 1.4:1. These included nine Escherichia coli, seven Enterobacter cloacae, four Citrobacter freundii and a single isolate each of Klebsiella spp. and Salmonella spp. A total of 17 isolates contained bla(CTX-M) (five bla(CTX-M-15), three bla(CTX-M-14) and nine bla(CTX-M-9)). ISEcp1 was present in isolates expressing CTX-M-14 and -15, but was absent upstream of In60-associated bla(CTX-M-9). E. coli isolates also contained either a bla(TEM-1) or bla(TEM-2), whereas six of the E. cloacae carried bla(SHV-12) and the Klebsiella spp. bla(SHV-36) in addition to bla(CTX-M-9). The single Salmonella spp. carried bla(SHV-12).

Conclusions: The overall prevalence of ESBL in isolates of Enterobacteriaceae from York was 1.9%. ESBL-producing isolates were found in both the community and hospital, with the CTX-M type most common. This is also the first report of an ESBL-producing Salmonella in the UK.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Community-Acquired Infections / epidemiology*
  • Community-Acquired Infections / microbiology*
  • Cross Infection / epidemiology*
  • Cross Infection / microbiology*
  • DNA, Bacterial / genetics
  • Drug Resistance, Bacterial
  • Enterobacteriaceae / drug effects*
  • Enterobacteriaceae / genetics*
  • Enterobacteriaceae Infections / epidemiology*
  • Enterobacteriaceae Infections / microbiology*
  • Genetic Variation
  • Humans
  • Microbial Sensitivity Tests
  • Reverse Transcriptase Polymerase Chain Reaction
  • United Kingdom / epidemiology
  • beta-Lactamases / metabolism*


  • DNA, Bacterial
  • beta-Lactamases