牛源大肠杆菌耐药表型与Ⅰ型整合子-基因盒的关系

Correlation between antimicrobial resistance and classⅠintegron-gene cassette of Escherichia coli isolated from cow

为了了解宁夏地区牛源大肠杆菌中Ⅰ型整合子-基因盒携带情况及其对细菌耐药性的影响。在获得245株大肠杆菌对16种抗菌药耐药情况的基础上,采用PCR技术对菌株的Ⅰ型整合子-基因盒进行扩增,PCR产物进行测序分析。结果显示Ⅰ型整合子检出率为14.29%;35株Ⅰ型整合子阳性菌株中32株菌扩增出7种类型的基因盒插入区片段,以介导甲氧苄啶和氨基糖苷类耐药的dfrA和aadA为主,基因盒排列dfrA17-aadA5和dfrA7较为流行,并且dfrA7为国内首次从牛源性大肠杆菌中发现。分析表明宁夏地区牛源大肠杆菌中Ⅰ型整合子目前还不是很流行,菌株的多重耐药表型与Ⅰ型整合子高度正相关。

In order to understand the prevalence of integron-gene cassette of Escherichia coli and the influence on antimicrobial resistance isolated from cow. After acquired the antimicrobial resist- ance patterns,the class t integron-gene cassette of clinical 245 strains of Escherichia coli were de- tected by PCR and PCR products were sequenced and analyzed. The results showed that the posi- tive rate of class I integron was 14.29%,and 7 types of the integrated gene cassttes were detected in 32 strains out of 35 integron-positive srtains,which encoded aminoglycoside adenyltransferase （aadA） and dihydrofolate reductase（dfrA） mostly,the dfrA17-aadA5 and dfrA7 were considerably epidemic. Analysis showed that Class I integron was not very prevalent at present in Ningxia while multiple antimicrobial-resistant strains phenotype was closely related to class I integron.