Direct sequencing of the amplified structural gene and promoter for the extended-broad-spectrum beta-lactamase TEM-9 (RHH-1) of Klebsiella pneumoniae

Plasmid. 1990 Jan;23(1):27-34. doi: 10.1016/0147-619x(90)90041-a.


Extended-broad-spectrum beta-lactamase TEM-9, detected in a clinical isolate of Klebsiella pneumoniae, confers high-level resistance to recent cephalosporins, in particular ceftazidime, and to the monobactam aztreonam. Using oligonucleotide probes, we found that the plasmid gene blaT-9 encoding TEM-9 differs from characterized blaT genes by a new combination of already known mutations. Gene blaT-9 was further studied by direct sequencing of an amplified 1.1-kb DNA fragment which contained the open reading frame and its promoter. Analysis of the nucleotide and of the deduced amino acid sequence confirmed the hybridization results and indicated that TEM-9 differs from TEM-1 by four amino acid substitutions: Phe at position 19 and Met at position 261, which have been found in TEM-4 and are known not to expand the enzyme substrate range; Lys 102, detected in TEM-3 and TEM-4, and Ser 162, present in TEM-5 and TEM-7. Each of the latter substitutions enlarges the substrate spectrum of the enzymes and they are found associated for the first time in TEM-9.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids
  • Base Sequence
  • DNA Transposable Elements
  • DNA, Bacterial / genetics
  • Genes, Bacterial*
  • Klebsiella pneumoniae / genetics*
  • Molecular Sequence Data
  • Mutation
  • Polymerase Chain Reaction
  • Promoter Regions, Genetic*
  • beta-Lactamases / genetics*


  • Amino Acids
  • DNA Transposable Elements
  • DNA, Bacterial
  • beta-lactamase TEM-9
  • beta-Lactamases