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

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。

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

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.