Molecular characterization of integrons in non-typhoid Salmonella serovars isolated in Japan: description of an unusual class 2 integron

J Antimicrob Chemother. 2005 Mar;55(3):371-4. doi: 10.1093/jac/dkh534. Epub 2005 Feb 10.


Objectives: To characterize class 1 and class 2 integrons among non-typhoid Salmonella enterica serovars in Japan, and also to monitor the spread of the multidrug-resistant S. enterica serovar Typhimurium DT104.

Methods: A total of 105 Salmonella isolates were included in this study. The broth microdilution method was used to determine the MIC values of a range of antibiotics for these isolates. PCR and DNA sequencing were used for screening and characterization of class 1 and class 2 integrons.

Results: PCR sequencing analysis revealed the presence of seven profiles of class 1 integrons in addition to a new type of class 2 integron. The identified gene cassettes within class 1 integrons were as follows; aadA1, aadA2 and aadA5, which confer resistance to streptomycin and spectinomycin; aadB, which confers resistance to gentamicin, kanamycin and tobramycin; dfrA1 and dfrA17, which confer resistance to trimethoprim; bla(PSE-1), which confers resistance to ampicillin; catB3, which confers resistance to chloramphenicol; and sat1, which confers resistance to streptothricin. Two strains of the multidrug-resistant S. Typhimurium DT104 were characterized in this study. DNA sequencing of class 2 integrons identified one with an unusual array of gene cassettes, sat, sat1 and aadA1.

Conclusions: In this study, we characterized the antibiotic resistance gene cassettes within class 1 integrons in different isolates of non-typhoid Salmonella serovars, and we also identified a new type of class 2 integron.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Drug Resistance, Multiple, Bacterial / genetics*
  • Integrons*
  • Molecular Sequence Data
  • Salmonella / drug effects
  • Salmonella / genetics*

Associated data

  • GENBANK/AB126601
  • GENBANK/AB126602
  • GENBANK/AB126603
  • GENBANK/AB126604
  • GENBANK/AB161461
  • GENBANK/AB186118
  • GENBANK/AB186119
  • GENBANK/AB186122