【摘要】 对分离的２７株猪源性大肠杆菌进行抗性试验，选取１０株双抗性菌株提取质粒ＤＮＡ，电泳分析表明各菌株均存在２～４条质粒ＤＮＡ带。将２１．２２７ｋｂ和５．１４８ｋｂ质粒转化大肠杆菌ＭＣ１０６１／Ｐ３，使其获得了相应菌株的抗性，转化菌纤毛蛋白与Ｋ８８、Ｋ９９高免血清琼扩试验为阴性，证明２１．２２７ｋｂ和５．１４８ｋｂ质粒未携带Ｋ８８、Ｋ９９基因。用２１．２２７ｋｂ转化菌注射小鼠，则小鼠死亡，说明２１．２２７ｋｂ携带毒力基因。更多还原

【Abstract】 The 10 double resistance bacterial strains were selected from the 27 Escherichia coli pig origin strains by antibiotic resistance test.Agarose gel electrophoresis of plasmid DNA purified from the 10 E·coli strains revealed the presence of 2～4 plasmid belts in each strain.The plasmids (21 227kb,5 148kb) were transformed to strain Mc1061/P3 and the transformants acquired resistance corresponded to E·coli strain.The fimbriae protein isolated from transformed strain Mc1061/P3 was negative after immunodiffusion with antiserum for K 88 、K 99 indicated that they didn’t carry genes encoding K 88 、K 99 antigens.The mice inoculated with Mc1061/P3 carrying plasmid 21 227kb died,the result showed that the plasmid 21 227kb might carry toxin gene.更多还原