Foundation And Application Of Multi-PCR Of Streptococcus Suis

Streptococcus suis(SS) is an important pathogen of swine.Thirty-five capsular serotype of Streptococcus suis have been described(tyupes1/2 and 1～34).Streptococcus suis type 2(SS2) is considered to be the highest virulent serotype and prevalent in worldwide. Streptococcus suis type 1(SS1),type 7(SS7) and type 9(SS9) were the main pathogens of swine strptococcosis and prevalent in Germany,Belgium,Spain,Holland and Finland.In China,SS2 was firstly isolated in Guangdong in 1991.The streptococcosis caused by SS2 broke out in Jiangsu and Sichuan in 1998 and 2005 respectively.Shanghai is one of the most sweeping swine breeding aquatics in China,therefore,it is necessary to investigate the circs of the streptococcus suis and its virulent factors,in order to prevent and control the streptococcosis in Shanghai.During 2006 - 2008,The Streptococcus suis type 2 were investiged through daily clinic samples and swine nose swab samples in the Shanghai animal disease control center.and established the fast method of Multi-PCR.Delivered sickness,the dead swine and the partial swine farm nose cotton swab to the Shanghai area which examined has carried on the Streptococcus suis type 2 epidemiology investigations from 2006 to 2008.And unified the raise characteristic and the shape,the dyeing situation and so on has carried on the preliminary appraisal to it,carried on the stereotypia to the doubtful strain with the PCR method.The result indicated that,12 SS2 were separated from 1536 sample;The biochemistry experiment result indicated the masculine separation biochemistry characteristic is unstable.The fast method of Multiplex PCR for detecting three virulence-associated factors based on the gene sequences of epf(the extracellular factor gene).sly(the suilysin gene)and gapdh(the fibronectin-binding protein gene),which was developed by combining and optimizing the threee virulence-associated factors.18 isolates were detected by the Multiplex assay.Both the positive control and negative control were successful.The results demonstrated that Multiplex PCR was highly specific and sensitive diagnostic tool for the detection of three virulence-associated factors of Streptococcus suis.Carries on the examination using the establishment multiplex PCR to 273 isolates.The result confirmed by separate further examination of epf,sly and the gapdh.The experiment proves that,99 isolates' gapdh are positive,144 isolates have epf and 214 isolates have sly.The results demonstrated that multiplex PCR was highly specific and sensitive diagnostic tool for the detection of three virulence-associated factors of Streptococcus suis.