关键词: 第1类整合子

Abstract: 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 suscept　ibility 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 ant　ibiogram 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 determinee the multiple- resistant antibiotics.

Key words: class 1 integron