[Objective] To elucidate the pathogenesis role of the vir region of APEC O2 strain E058.[Methods] The gene aerobactin/sitABC operon knockout mutants E058Δvir of APEC E058 strain was generated using Red recombination system.A series of pathogenicity tests including chick embryo inoculation,the competition experiment and the colonization and persistence in vivo were used to evaluate the pathogenicity of APEC E058Δvir and the wild-type strain E058.[Results] E058Δvir was similar to its parental strain E058 in the growth curves,invasion assays of HD-11 cell and in vitro competition assay.In the colonization and persistence test,the recovery colonies of E058Δvir were significantly decreased in all of the organs tested (P ＜ 0.001).[Conclusions] These results indicate that the virulence factors encoded by aerobactin/sit operon genes were important for the pathogenesis of APEC E058.%[目的]探究毒力基因aerobactin与sit操纵子与禽致病性大肠杆菌E058株致病作用的相关性.[方法]利用Red同源重组方法,构建APEC E058株aerobactin与sit操纵子基因缺失株E058Δvir,并通过一系列的体内及体外试验对其生物学特性进行研究.[结果]生长曲线测定、细菌侵袭试验及体外竞争等试验结果表明,突变株与亲本株差异不显著；体内动态分布试验结果显示,突变株E058Δvir在5个被检脏器中均极显著地低于亲本株(P＜0.001).[结论]aerobactin与sit操纵子与禽致病性大肠杆菌E058株的致病性相关,是其重要的致病因子.
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