Isolation And Identification And Pcr Assay Of Streptococcus Suis Type 2

Streptococcus suis type 2(SS2) is an important pathogen of porcine streptococcosis, which not only infects swine,with lymphatic abscess,meningitis,arthritis,sepsis and sudden death as major clinical manifestions,but also causes severe infection and even death of related practitioners.Therefore it is an important zoonotic disease pathogens of the zoonosis.This study revealed the etiological properties and established the molecular biological detection of streptococcosis suis in shaanxi province based on the bacteriological isolation and identification,antibiotic sensitivity tests,and the PCR detection of virulence factors of streptococcus suis type 2.In the microbiological identification 10 strains of streptococcus suis were isolated in 20 pathological samples of suspected dead or diseased cases in pig farm A(four strains) and pig farm B(six strains) in shaanxi province according to the cultivating performance, bacteria's staining properties,microscopic observation,and biochemical tests.Totally 18 bactericides against Gram-positive bacteria were used in antibiotic sensitivity test on the isolated 10 strains. The results showed that four strains from farm A were highly sensitive to fortum, polymyxin nikkomycin and cefalotin but markedly resistant to penicillin, ampicillin, erythromycin, norfloxacin, ciprofloxacin and amoxicillin.And six strains from the farm B were highly sensitive to cefotaxime, fortum, rifampicin,polymyxin but highly resistant to penicillin, ampicillin, erythromycin,cotrimoxazole,norfloxacin and ciprofloxacin.And isolated 10 strains were highly pathogenic for mouse.In PCR assay three pairs of primers were respectively designed based on capsular polysaccharide (CPS),muramidase-released protein (MRP), extracellular factor (EF) genes of streptococcus suis type 2 and genes of 10 isolated strains amplified.The results showed that the sizes of CPS, MRP and EF genes were 450bp, 532bp, 269bp respectively,all according with the expected designs, indicating that the streptococcosis in two farms of Shaanxi province was caused by streptococcus suis type 2. These studies provided microbiological and molecular biological foundation for the diagnosis and control of streptococcosis in Shaanxi province.