Diversity of CTX-M beta-lactamases and their promoter regions from Enterobacteriaceae isolated in three Parisian hospitals

FEMS Microbiol Lett. 2002 Apr 9;209(2):161-8. doi: 10.1111/j.1574-6968.2002.tb11126.x.


Nine clinical isolates of Enterobacteriaceae (six Escherichia coli and three Proteus mirabilis) isolated in three Parisian hospitals between 1989 and 2000 showed a particular extended-spectrum cephalosporin-resistance profile characterized by resistance to cefotaxime and aztreonam but not to ceftazidime. CTX-M-1, CTX-M-2, CTX-M-9, CTX-M-14 and two novel plasmid-mediated CTX-M beta-lactamases (CTX-M-20, and CTX-M-21) were identified by polymerase chain reaction and isoelectric focusing (pI>8) and were associated in eight cases with TEM-1 (pI=5.4) or TEM-2 (pI=5.6) beta-lactamases. We used internal ISEcp1 and IS26 forward primers and the CTX-M consensus reverse primer to characterize the CTX-M beta-lactamase promoter regions and showed their high degree of structure diversity. We found upstream of some bla(CTX-M) genes, a 266-bp sequence 100% identical to the sequence upstream of the Kluyvera ascorbata beta-lactamase gene, suggesting that this chromosomal enzyme is the progenitor of the CTX-M-2/5 cluster.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cephalosporin Resistance / genetics*
  • DNA Transposable Elements
  • Escherichia coli / genetics*
  • Escherichia coli Proteins*
  • Genetic Variation
  • Hospitals*
  • Humans
  • Molecular Sequence Data
  • Paris
  • Plasmids
  • Promoter Regions, Genetic / genetics*
  • Proteus mirabilis / genetics*
  • beta-Lactamases / genetics*


  • DNA Transposable Elements
  • Escherichia coli Proteins
  • CTX-M-9 protein, E coli
  • beta-lactamase CTX-2
  • beta-lactamase CTX-M-14
  • beta-lactamase TEM-3
  • beta-Lactamases