健康人肠道大肠埃希菌整合子和耐药基因盒的研究

目的：研究健康人肠道大肠埃希菌的整合子携带情况与整合子携带的基因盒种类及其与耐药性之间关系.方法：PCR检测Ⅰ类整合子,确定细菌携带整合子的情况.整合子阳性菌株进一步检测整合子的可变区,分析插入基因盒的序列.结果：150株大肠埃希菌中有38株携带Ⅰ类整合子,集中分布在对3种以上抗生素耐药的菌株中.插入基因盒集中在甲氧苄氨嘧啶耐药基因（dfr）和氨基糖甙类抗生素耐药基因（aadA）.结论：细菌的多重耐药性与整合子携带高度一致,但是细菌耐药谱和其整合子无对应关系.

ANALYSIS THE INTEGRON AND ANTIBIOTIC RESISTANCE GENE CASSETTE IN ESCHERICHIA COLI ISOLATED FROM HEALTHY PERSON

Objective:To investigate the relationship between antibiotic resistance of Escherichia coli strains isolated from healthy person and the integrons and gene cassettes they harbored.Methods:PCRs amplifying intI(integrsel) gene and the variable region between the conserved segments(CS-PCR) were performed for class1 integron.And the integron content of every isolate was characterized by RFLP(Restriction Fragment Length Polymophism) analysis and sequencing.Results:30 of 150 isolates were identified as positive for integrase 1 gene in the total DNA.All the integron-positive strains were resistant to more than 3 antibiotics.Most of the gene cassettes integrated in the integrons conferred resistant against trimethoprim(dfr7 dfr12 dfr17 dfrA1) and streptomycin-spectinomycin(aadA1 aadA2 aadA5).Conclusions:There was a good correlation between Integron-carrying and the antibiotic resistance of Escherichia coli strains isolated from Healthy person,but the antibiotic profile of an individual strain did not consist with the gene cassettes of the integron it harbored.