Relationship between antibiotic resistance and class 1 integron of Escherichia coli isolated from healthy human

Objective To investigate the level and molecular characteristics of class 1 integron in Escherichia coli strain isolated from healthy human of Beijing and to analyze the relationship between antibiotic resistance of Escherichia coli and the class 1 integron.Methods The anon icrobial susceptibility test of 150 Escherichia coli isolates was perfouned with Microscan Vitek32 and disk diffusion assay.Class 1 integron was amplified by PCR with total DNA.The purified amplicons of class 1 integronwas characterized by RFLP analysis and sequencing.The integronpositive isolates were typed by PFGE.Results Eighty-three (55.3%)isolates were multidmg resistant(resistance to over 3 antibiotics).Five isolates (3.3%) produced ESBL、Class 1 integron wasp resent in 42 isolates The size of class 1 integron was foam 150 by to 3 000 bp.Most of the gene cassettes integrated in the integron conferred resistance against trinethoprin and streptomycin-spectinomycin,and integrons with the dfr17-aadAS gene cassettes combination were predominant Class 1 integron distributed in different geno-type Escherichia coli strain isolate.Conclusion There was a good correlation between integron-carrying and the antibiotic resistance of Escherichia coli strains isolated from healthy human in Beijing Genotyping suggests horizontal intraspecies transfer of integron Integrons plays an important role in mediation of antibiotic resistance.