| Streptococcosis suis is an important pathogen which is harmful to modern swineindustry and it nearly happened the whole world. Because of its great variety of serotypeand the complex structure of antigen, it presents different clinical symptom, such assepticemia, meningoencephalitis, endocarditis, pneumonitis, porodenia arthritis etc and itusually mixes infection with other pathogen. It often befells on in 3-to 12-week-oldpiglets. Infections due to S. suis have also been identified in more and more mammals(including human) and birds, it imperils human public health now.The infectors of the Pig streptococcosis are many kinds of hemolytic streptococcus. Itis Gram-positive bacterial. According to serological reaction, 20 serotypes have beenidentified, the more important serotypes are A, B, C, D, E, F, L, R. Among this serotypes,the R serotype and F serotype not only infected swine but also to human beings. Severalcases about human infection with S.suis have been reported in domestic and international.Based on its polysaccharide capsular antigens, at least 35 S.suis capsular types havebeen described, of which capsular type 2 is the most prevalent in diseased animal,followed by capsular type 1, 7 and 9. The virulence factor this bacterium and interactionbetween virulence factors is poorly understand.Resently years, we collected the infected organs from the pigs which are sent fromthe province near HuBei. For studying the epidemic of S.suis, and finding a methodwhich can quickly,safty and effective for treating and controlling the disease, we didreseach as follow:1. Between 2003—2007, 472 strains of pathogenic streptoccus of swine were isolated inHuBei,HuNan,JiangXi,HeNan,AnHui and so on.2. Group identification of 472 pathogen Streptococcus strains from swine used Lancefielddiagnostic kit A～G. The results were group D 258/472(54.5％), group G 51/472(10.8％),group D/F 25/472(5.29％), group F 25/472(5.29％), group C 4/472(0.84％), group B3/472(0.63％), group D/G 3/472(0.63％) respectively, and 103 strains couldn'tidentification by using Lancefield diagnostic kit.3. A pair of primer gdh which was the major virulence genes were designed, using PCRassay, we found 260(55.1％) strains of Streptococcus suis.4. According to the correlated information: 4 pairs of primers to the major virulence geneswere designed, of which one pair was based on capsular polysaccharide genes specific forserotype 2 (cps2), and the other 3 pairs were based on the virulence genes epf, mrp andsly. 260 strains of Streptococcus suis in which 101 strains belonged to serotype 2(38.8％) were identified by means of the PCR assays. With the 77 strains of Streptococcus suisserotype 2, the phenotypes were: cps2/ef+/sly+/mrp+ were 44 strains(57.1％);cps2/ef-/sly-/mrp- were 9 strains(11.7％); cps2/ef-/sly-/mrp+ were 15 strains(19.5％);cps2/ef-/sly+/mrp+ were 3 strains(3.9％); cps2/ef-/sly+/mrp- were 3 strains(3.9％);cps2/ef+/sly-/mrp+ were 2 strains(2.6％); cps2/ef+/sly-/mrp- was 1 strains(1.3％).5. The result of biochemical test with SS2: such as glucose, ribose, mannitol, mannitose,D-glucitol, lactose, gossypose, arabinose, esculin, hippurate, starch, arginine, MR, VP.We found biochemistry characteristics of the SS2 were much more different, to fermentsaccharic is inertia and instability, it is difficult to classified.6. In the period of much more swines disaesed, we used self-made inactivated tissuevaccine for pig streptococcosis during July and August in 2006, combined with bloodserum with high antibody. It's a good method for controling the disease to spread.
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