Phenotypic and Genotypic Characterization of Antibiotic Resistance Integrons in Salmonella enterica serovar Newport

Numerous recent outbreaks of Salmonella enterica have been found to be resistant to multiple antibiotics, which only exacerbate an already serious infection. Integrons, which are mobile DNA elements, have been found in previous studies to contribute to antibiotic resistance. Two consistently observed integrons (1.0 kb and 1.2 kb) were cloned and introduced into an antibiotic sensitive strain of Escherichia coli. Upon phenotypic characterization, the 1.0 kb integron was found to confer resistance to streptomycin. Genotypic characterization supported this finding with the presence of the aaD1 gene in the integron cassette. The 1.2kb integron was unable to be phenotypically characterized, but genotypic characterization showed the presence of potential antibiotic resistance genes. The 1.8 kb integron has yet to be successfully cloned. This characterization demonstrated that these integrons contribute to the antibiotic resistance profile observed in the Salmonella enterica.