Characterisation of Two New Gene Cassettes, aadA5 and dfrA17

FEMS Microbiol Lett. 2000 Jan 15;182(2):265-9. doi: 10.1111/j.1574-6968.2000.tb08906.x.


Escherichia coli INS33 was isolated from the urinary tract of an infected patient. It was resistant to ampicillin, chloramphenicol, spectinomycin, streptomycin, sulfafurazole, tetracycline and trimethoprim. PCR screening revealed the presence of a class 1 integron that harboured two new gene cassettes, designated dfrA17 and aadA5. The new dfrA17 cassette was 91% identical to the known dfrA7 cassette. The aadA5 cassette was 95% identical over the first 830 bp to aadA4, but lacked the IS26 element found at the 3' end of this truncated cassette. Cloning and expression of the cassette region demonstrated that dfrA17 conferred high level resistance to trimethoprim but aadA5 conferred resistance to spectinomycin but not to streptomycin.

MeSH terms

  • Amino Acid Sequence
  • Anti-Bacterial Agents / pharmacology
  • Cloning, Molecular
  • DNA Transposable Elements*
  • Drug Resistance, Microbial / genetics*
  • Escherichia coli / drug effects*
  • Escherichia coli / genetics*
  • Escherichia coli / isolation & purification
  • Escherichia coli Infections / microbiology*
  • Humans
  • Integrases / genetics
  • Microbial Sensitivity Tests
  • Molecular Sequence Data
  • Nucleotidyltransferases / chemistry
  • Nucleotidyltransferases / genetics*
  • Phylogeny
  • Sequence Analysis, DNA
  • Trimethoprim Resistance / genetics*
  • Urinary Tract Infections / microbiology


  • Anti-Bacterial Agents
  • DNA Transposable Elements
  • Integrases
  • Nucleotidyltransferases
  • streptomycin 3''-adenylyltransferase

Associated data

  • GENBANK/AF169041