Study On Virulence-Associated Factor Of Streptococcus Suis 2 In Guangxi

A sensitive and specific mμltiplex PCR assay for virulence-associated factors which including CPS,MRP,EF and SLY gene of Streptococcus suis 2 was established in this study.The target strain of serotype of Streptococcus suis 2 coμld be detected definitely when the template contained as few as 20 cfu. Use this mμltiplex PCR assay,138 Streptococcus suis 2 isolates from Guangxi were detected.The resμlts confirmed that in 127 isolates from slaughtered healthy pig's tonsil,there are 104(81.9%)strains belong to mrp+epf+sly+ and mrp+epf+sly-,1 strain belongs to mrp+epf-sly+,12 strains belong to mrp+epf-sly-and 10 strains belong to mrp-epf-sly-.At the same time,56 strains which have MRP gene were cloned and partial sequenced.The resμlts showed all this strains coμld be divided into two genotypes asⅠandⅡ,genotypeⅡcoμld be divided into 2 sub-genotypes asⅡa andⅡb.34 strains GX01,GX20-2, GX4Lin,GX6Lin,GXLP5,GXB30,GXB45,GXB102,GXB141,GXBM20, GXCDX23,GXCDX49,GXDL9,GXDL36,GXFS26,GXG42,GXG121, GXGG34,GXGL462,GXLB72,GXLB131,GXLP26,GXLS53,GXQL31, GXQP46,GXR147,GXRA63,GXWX193,GXWX209,GXWZ80,GXY134, GXY153,GXY160 and GXZ22 belong to genotypeⅠ;22 strains GX2Lin, GX11Lin,GXB74,GXB70,GXCLZ192,GXG6,GXGG35,GXGL547, GXHP99,GXJZ26,GXLJ122,GXQL11,GXQL25,GXR128,GXRA32, GXW32,GXW45,GXWX400,GXWZ241,GXYL12,GXYL16 and GX12Lin belong to genotypeⅡ,of which GX2Lin,GX11Lin,GXB74,GXB70, GXCLZ192,GXG6,GXGG35,GXGL547,GXHP99,GXJZ26,GXLJ122, GXQL11,GXQL25,GXR128,GXRA32,GXW32,GXW45,GXWX400, GXWZ241,GXYL12 and GXYL16 are in sub-genotypesⅡa,GX12Lin is in sub-genotypesⅡb.There were 29 strains isolated from healthy pigs and 5 strains isolated from diseased pigs in genotypeⅠ,the nucleotide homologies of them were 98.8%to 99.9%.In sub-genotypeⅡa,there were 20 strains isolated from healthy pigs and 2 strains isolated from diseased pigs,the nucleotide homologies of them were 98.0%to 99.7%.The nucleotide homologies between genotypeⅠandⅡwas 71.1%to 72.9%.