title: Occurrence of integrons and resistance genes among sulphonamide-resistant Shigella spp. from Brazil.
abstract: OBJECTIVE
  To determine the occurrence of class 1 and 2 integrons and antimicrobial resistance genes among sulphonamide-resistant Shigella strains isolated in Brazil during 1999-2003.
  
  
  METHODS
  Sixty-two Shigella (Shigella flexneri, n = 47 and Shigella sonnei, n = 15) were tested against 21 antimicrobial agents. The presence of integrons classes 1 and 2 and antimicrobial resistance genes was investigated by PCR using specific primers.
  
  
  RESULTS
  A total of eight antimicrobial resistance profiles were identified, with the profile of resistance to sulfamethoxazole, trimethoprim, spectinomycin, streptomycin and tetracycline being the most common among S. sonnei, and additionally to ampicillin and chloramphenicol among S. flexneri. Class 1 integrons were found in only two strains, whereas class 2 integrons were found in 56 (90.3%) of the strains. All class 2-positive strains had a similar fragment of 2214 bp harbouring a gene cassette array conferring resistance to trimethoprim, streptothricin and spectinomycin/streptomycin. The genes coding for resistance to chloramphenicol (catA1), tetracycline [tet(A) and tet(B)] and ampicillin (bla(OXA) and bla(TEM)), were detected in resistant strains.
  
  
  CONCLUSIONS
  The detection of class 1 and 2 integrons and additional antimicrobial resistance genes allowed us to identify the most frequent antimicrobial resistance patterns of Shigella spp. isolated in Brazil.
authors.affiliation: Oswaldo Cruz Institute, Avenida Brasil 4365, 21045-900 Rio de Janeiro, Brazil.
authors.forename: Gisele
authors.initials: G
authors.lastname: Peirano
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Agersø
authors.forename: Frank M
authors.initials: FM
authors.lastname: Aarestrup
authors.forename: Dalia
authors.initials: D
authors.lastname: dos Prazeres Rodrigues
mesh_terms: D004251:DNA Transposable Elements; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D032023:Integrons; D012760:Shigella / Q000187:drug effects / Q000235:genetics*; D013449:Sulfonamides / Q000494:pharmacology*
chemical_list: D004251:DNA Transposable Elements; D013449:Sulfonamides