Genetic Characterization of Antimicrobial Resistance in Canadian Isolates of Salmonella Serovar Typhimurium DT104

Abstract
PCR was used to identify antibiotic resistance determinants in 31 Canadian Salmonella serovar Typhimurium DT104 isolates. Genes encoding resistance to ampicillin (pse1 orblaP1), chloramphenicol (pasppflo-like), streptomycin-spectinomycin (aadA2), sulfonamide (sulI), and tetracycline [tet(G)] were mapped to a 13-kb region of DNA of one isolate. Two copies of sulIwere identified and mapped to the 3′ end of either pse1 oraadA2 integrons. The two integrons were separated by thepasppflo-like gene and the tet(G) gene. The kanamycin resistance determinant (aphA-1) was present on a 2.0-MDa plasmid (five isolates) or on the chromosome (three isolates).