禽致病性大肠杆菌E058株毒力基因(aerobactin)与sit操纵子基因突变株的构建及其致病性

Construction of aerobactin and sit operon mutant of avian pathogenic Escherichia coli E058 and evaluation of its pathogenicity

【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。

[ Objective] To elucidate the pathogenesis role of the vir region of APEC 02 strain E058. [ Methods] The gene aerobactin/sitABC operon knockout mutants E058Avir 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 E058Avir and the wild-type strain E058. [ Results] E058Avir 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 E058Avir were significantly decreased in all of the organs tested （P 〈 0. 001 ）. [ Conclusions] These results indicate that the virulence factors encoded by aerobactin/sit oberon genes were important for the nathogenesis of APEC E058.