不同动物源性大肠杆菌多重耐药调控基因rob的同源性分析

Homology analysis of multidrug-resistance regulating gene rob of Escherichia coli from different animal species

为研究大肠杆菌多重耐药调控基因rob与不同动物源性及多重耐药水平之间的关系,选取临床分离的不同动物源性大肠杆菌5株及大肠杆菌药敏质控株ATCC25922,在对其进行主要治疗药物耐药性检测的基础上,分别以其染色体DNA为模板,通过PCR反应扩增出大肠杆菌多重耐药调控基因rob,将该基因分别与克隆载体pMD18-T连接,连接产物转化至大肠杆菌JM109感受态细胞中,对经酶切与PCR反应鉴定为阳性的克隆质粒进行了核苷酸序列测定。测序结果表明:不同动物源性大肠杆菌的rob基因与Gen-Bank中该基因的核苷酸序列及所推导的氨基酸序列的同源性较高。不同源性大肠杆菌的rob基因的核苷酸序列与其动物源性有关,该基因的核苷酸序列的个别突变位点可能影响AcrAB外输泵的表达水平,进而影响其多重耐药水平。

In order to study the relationship between multidrug-resistance regulating genes rob of Escherichia coli from different animal species and levels of multidrug-resistance,5 strains of E. coli isolated from different animal species and control strain ATCC25922 were selected. Based upon drug-resistance detection of main therapeutic drugs,rob genes of multidrug-resistance of E. coli were amplified by PCR from chromosome DNA of E. coli and ligated into pMD18-T Simple Vector. The ligated products were translated into E. coli JM109. A positive plasmid identified by enzymatic digestion and PCR was sequenced. The sequencing result indicated that homology of nucleotide sequences of and deduced amino acids from the rob genes between the 5 E. coli isolates and that of GenBank were high. Some gene mutations of rob gene of the 5 E. coli isolates were related to animal species and to the level of drug resistance by affecting on the expression level of AcrAB efflux pump.