Identification and characterization of class 1 integron among E. coli from healthy students' enteric strains / 吉林大学学报(医学版)

ABSTRACT

Objective To explore the distribution and characterization of class 1 integrons in E.coli from healthy feces,and to elucidate the status of gene-cassettes.Methods Routine method was used to isolate E.coli,antibiotics susceptibility was tested by the disk diffusion method;class 1 integron was detected by PCR assay;PCR products were sequenced and analyzed.Results Of 97 samples,76 isolates were identified,and 25 isolates were multiple-drug resistant.The antibiogram was sulfamethoxazole-trimethoprim,ampicillin,streptomycin,tetracycline,erythromycin.14 of 25 isolates carried class 1 integrons,and the size of integrons differed from 1 800 bp(10 strains) to 750 bp(4 strains).The sequenced PCR product demonstrated that the 1 800 bp integron laboured aadA1-dfrA14-orf gene cassette conferred the resistance to sulfamethoxazole-timethoprim,streptomycin and aminoglycoside;the 750 bp integron laboured dfrA14 gene cassette conferred the resistance to sulfamethoxazole-trimethoprim.Conclusion The different kinds of class 1 integrons exist in E.coli from the healthy students,and determine the multiple-resistant antibiotics.