多重抗药大肠杆菌中Ⅰ型整合子的分布与抗药关系

目的检测多重抗药大肠杆菌中检测Ⅰ型整合子的携带率及其对细菌抗药性的影响。方法用大肠杆菌显色．培养基分离奶牛场、猪场和肉鸡场的565株大肠杆菌，测定其对15种抗生素的MIC；用PCR扩增其中91株多重抗药性（最少耐3种抗生素）菌株的Ⅰ型整合酶基因及抗药基因盒。结果565株大肠杆菌仅对头孢噻呋、阿米卡星和硫酸粘菌素的抗药率低于50％，其余药物均表现出较高抗药率，且几乎所有细菌都对3种以上抗生素具有抗性。91株多重抗药大肠杆菌Ⅰ型整合子的平均检出率为83．52％，大多数整合aadA基因和dhfr基因，抗药性基因携带率为43．42％。结论Ⅰ型整合子对细菌多重抗药性的产生和传播起着重要作用，是临床细菌多重抗药性监测在基因水平的重要指标。

Distribution of the class I integron in Escherichia coli with multidrug resistance and its relationship to drug resistance

To find out the carriage rate of the type I integron in Escherichia coli with multidrug resistance and its influence to drug resistance, 565 strains of Escherichia coli was isolated from farms, such as farms of daily milk cows, pigs and chicken with CHROM agar coloration medium. The drug susceptibility of these isolates to 15 antibiotics was detected and their minimal inhibitory concentrations （MICs） were determined. Meanwhile, the type Ⅰ integron gene and its related gene cassettes in 91 strains of isolates with multidrug resistance （at least resistant to 3 antibiotics） were amplified with PCR. It was found that almost all of the 565 isolates, were resistant to antibiotics （more than 3 antibiotics） tested only excluding CS, AK and COL, in which the rates of drug resistance of these antibiotics were less than 50%. The average detection rate of the type I in- tegron and the related gene cassettes in 91 strains of E. coli with multidrug resistance was 83.52 % and 43.42 % respectively. The gene cassettes integrated with various type Ⅰ integrons almost all belonged to aadA gene and dhfr gene. It is apparent that type Ⅰ integron in E. coli with multidrug resistance may play an important role in the development and spreading of the multi drug resistance and appears to be an important index of surveillance of the clinical multidrug resistance at genetic level.