Investigation into the itegrons on plasmid DNA of Salmonella

Objective To analyze the molecular feature of integrons on plasmid DNA in Salmonella. Methods The susceptibility of 32 Salmonella isolates to antibiotics were tested by Microscan WalkAway40 and the disk diffusion assay. Plasmid DNA was extracted. Class 1 integrons,intI2 and intI3 were detected by PCR. The purified amplicons of class 1 integrons were sequenced,and gene cassettes were identified. Results There 12 isolates carried class 1 integrons on plasmid DNA. The sizes of class 1 integrons were 1 000bp and 1 700bp respectively. 1 000bp integron carried gene cassette aadA1,1 700bp integron carried gene cassette dfr17-aadA5. There were no IntI2 and intI3. Conclusion Integrons are widely carried by Salmonella. Integrons are important molecular mechanism in mediation and dissemination of antibiotic resistance in Salmonella.