crp缺失对猪霍乱沙门氏菌强弱毒株毒力的影响

Effects of crp Deletion on the Virulence of Virulent and Attenuated Strains of Salmonella choleraesuis

猪霍乱沙门氏菌C500株是用化学方法将强毒株C78-1致弱,用于预防仔猪副伤寒的弱毒疫苗株,虽具有较好的免疫原性,但仍有一定的残余毒力。SC-1是临床分离的猪霍乱沙门氏菌强毒株。为了研制更加安全的弱毒株,利用重组自杀性质粒通过接合转移的方法构建了猪霍乱沙门氏菌C500株、C78-1及SC-1的crp缺失株。C78-1、crp-C78-1、SC-1、crp-SC-1、C500、crp-C500 6个毒株经小鼠毒力试验检测。LD50结果显示,crp缺失对猪霍乱沙门氏菌的毒力影响不大,毒力只是略为降低,其中以crp-C500株毒力最弱。综上所述,可以选用crp-C500株毒株作为猪霍乱沙门氏菌弱毒疫苗株的选择。

Salmonella choleraesuis C500 strain was an attenuated vaccine strain used to prevent piglet paratyphoid,attenuated from virulent strain C78-1 by chemical method.Although the vaccine has good immunogenicity,it remains some residual virulence.SC-1 was a virulent Salmonella choleraesuis strain isolated from clinical piglet.In order to develop a safer vaccine strain,cAMP receptor protein（crp） deletion mutant of C500,C78-1 and SC-1 was constructed by conjugation with recombination suicide vector.The virulence to mice of 6 strains,including SC-1,crp-SC-1,C78-1,crp-C78-1,C500 and crp-C500,were characterized.The LD50 results showed that crp delection little effect the virulence of Salmonella choleraesuis and crp-C500 mutant was the lowest.In collusion,crp-C500 mutant can be used as an candidate strain for preparing Salmonellacholeraesuis attenuated vaccine.