Characterization of antimicrobial resistance patterns and class 1 integrons in Escherichia coli O26 isolated from humans and animals

Antimicrobial resistance patterns and the prevalence of antimicrobial resistance genes and class 1 integrons in 35 Escherichia coli 026 isolated from humans and food-producing animals were evaluated. All isolates were resistant to cefaclor, cefalothin and sulfonamide and were susceptible to amikacin, gentamicin, cefmetazole, cefotaxime, ceftriaxone, ciprofloxacin, norfloxacin and trimethoprim. Most isolates were resistant to aztreonam, ampicillin, tetracycline, streptomycin and kanamycin. All ampicillin- and streptomycin-resistant E. coli 026 carried ampC and strA-strB gene sequences, respectively. Florfenicol- and chloramphenicol-resistant isolates carriedfloR but not cm1A. Class I integrons were identified in 14% of E. coli 026 isolates. To our knowledge, this is the first report describing the presence of multiple antimicrobial resistance genes in E. coli 026 isolated from human and animal origins.