Molecular characterization of In50, a class 1 integron encoding the gene for the extended-spectrum beta-lactamase VEB-1 in Pseudomonas aeruginosa

FEMS Microbiol Lett. 1999 Jul 15;176(2):411-9. doi: 10.1111/j.1574-6968.1999.tb13691.x.


A clinical isolate of Pseudomonas aeruginosa, JES, was resistant to extended-spectrum cephalosporins with a marked synergistic effect with clavulanic acid on a routine antibiogram. Preliminary PCR analysis revealed the presence of blaVEB-1, an integron-located gene encoding an extended-spectrum beta-lactamase previously identified in Escherichia coli MG-1. Using class 1 integron primers and blaVEB-1 intragenic primers, the insert region of the blaVEB-1 containing integron along with some flanking sequence from P. aeruginosa JES was amplified and subsequently sequenced. In50 contains within its variable region, in addition to qacE delta 1 and sull genes commonly found in class 1 integrons, two gene cassettes, veb1 and aadB. In50 is peculiar since its attI1 site is interrupted by two novel insertion sequences, IS1999 and IS2000. P. aeruginosa JES and Escherichia coli MG-1 strains were isolated from patients previously hospitalized in south east Asian countries. The finding of blaVEB-1 in these strains and on different integrons underlines the interspecies spread of this integron-located extended-spectrum beta-lactamase gene.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Chromosome Mapping
  • Chromosomes, Bacterial
  • DNA Transposable Elements
  • DNA, Bacterial
  • Drug Resistance, Microbial
  • Escherichia coli / genetics
  • Escherichia coli Proteins
  • Genes, Bacterial
  • Interspersed Repetitive Sequences
  • Microbial Sensitivity Tests
  • Molecular Sequence Data
  • Polymerase Chain Reaction
  • Pseudomonas aeruginosa / drug effects
  • Pseudomonas aeruginosa / enzymology
  • Pseudomonas aeruginosa / genetics*
  • Pseudomonas aeruginosa / isolation & purification
  • beta-Lactamases / genetics*


  • DNA Transposable Elements
  • DNA, Bacterial
  • Escherichia coli Proteins
  • beta-lactamase VEB-1, E coli
  • beta-Lactamases

Associated data

  • GENBANK/AF133697
  • GENBANK/AF133698
  • GENBANK/AF133699