猪链球菌国内分离株毒力因子的分布特征

为了研究国内致病性猪链球菌(Streptococcus suis,SS)的毒力因子分布特征,本试验选取猪链球菌7种主要毒力因子—谷氨酸脱氢酶(gdh)、荚膜多糖(cps2J)、溶菌酶释放蛋白(mrp)、胞外因子(epf)、溶血素(sly)、纤连蛋白/血纤蛋白原结合蛋白(fpbs)和毒力相关序列orf2,设计并合成7对引物,用PCR方法进行检测。结果显示:25株猪链球菌2型(SS2)国内分离株,96%(24/25)表现为cps /gdh /epf /mrp /sly /fbps /orf2 ,仅1株表现为cps /gdh /epf-/mrp /sly /fbps /orf2 ;1株猪链球菌1型(SS1),表现为cps-/gdh /epf-/mrp-/sly /fbps-/orf2 ;1株猪链球菌7型(SS7)国内分离株,表现为cps-/gdh /epf-/mrp-/sly /fbps-/orf2 ;2株猪链球菌9型(SS9)国内分离株,均表现为cps-/gdh /epf-/mrp-/sly-/fbps-/orf2 ,可见国内SS2的毒力基因分布特征与欧美等国家明显不同,提示我国目前SS2的主要流行菌株是同时具有7种毒力因子的高致病菌株。

Distributional Characteristics of Virulence-associated Gene of Streptococcus suis Strains Isolated from China

To investigate the distribution of virulence associate factors of Streptococcus suis(SS),seven virulence factors were detected by PCR amplification,namely the glutamate dehydrogenase gene(gdh),the capsular polysaccharides gene(cps),the extracellular factor gene(epf),the muramidase-released protein gene(mrp),the suilysin gene(sly),the fibronectin-binding protein gene(fpbs) and the virulence-associated sequence orf2.Twenty-nine virulent isolates from China including twenty-five SS2,one SS1,one SS7 and two SS9,were detected by PCR method.96%(24/25) were positive of cps /gdh /epf /mrp /sly /fbps /orf2 and only one virulent SS2 isolate was cps /gdh /epf-/mrp /sly /fbps /orf2 .Two strains of SS1 and SS7 were cps-/gdh /epf-/mrp-/sly /fbps-/orf2 ,while,two strains of SS9 were cps-/gdh /epf-/mrp-/sly-/fbps-/orf2 .The results showed the distribution of virulent associate factors of virulent streptococcus suis in China was different from isolates of Europe.The prevalent strains of SS2 in China were highly virulent stains which contain all seven virulence factors.