【摘要】 为确定不同毒力因子对大肠杆菌毒力的影响,选用7株不同毒力基因型(分别为Stx2e+、LEE+、LEE+HPI+、Stx2e+HPI+、F18+Stx2e+、F18+Stx2e+LEE+和F18+Stx2e+ST1+LT1+LEE+)的猪源大肠杆菌为材料,以消化道为感染途径,测定了其对30日龄健康ICR小鼠的半数致死量(LD50)。结果表明,以上7株大肠杆菌的LD50分别为1.504×109,5.986×108,3.777×108,1.504×108,5.986×107,3.777×107cfu/mL和1.504×107cfu/mL;确定了不同毒力基因型的大肠杆菌之间存在毒力差异,其中S462234株(F18+Stx2e+ST1+LT1+LEE+)的毒力最强,S452623株(Stx2e+)的毒力最弱,S462234株的毒力是S452623株的100倍。更多还原

【Abstract】 To investigate the effects of different virulent factors of Escherichia coli on pathogenesis,7 different virulent type E.coli strains,such as Stx2e⁺,LEE⁺,LEE⁺HPI⁺,Stx2e⁺HPI⁺,F18⁺Stx2e⁺,F18⁺Stx2e⁺LEE⁺and F18⁺Stx2e⁺ST1⁺LT1⁺LEE⁺ were tested in 30 days old ICR mice.The data showed that the LD₅₀ of the 7 strains were 1.504×10⁹,5.986×10⁸,3.777×10⁸,1.504×10⁸,5.986×10⁷,3.777×10⁷ cfu/mL and 1.504×10⁷ cfu/mL,respectively.It suggested that the different virulence among the different virulent type E.coli strains were occurred,such as the strain with F18,Stx2e,ST1,LT1 and LEE genes was more virulent than the strain only with Stx2e gene and the others.更多还原