Isolation And Identification Of Streptococcus Suis2and Development Of Propolis-adjuvant Inactive Vaccine

Isolation of pathogen from brain tissue of sick pigs with respiratory infection andneural symptoms, through morphology observation, biochemical test, PCR detection,drug sensitivity test and animal pathogenic test, results showed we separated a pigStreptococcus serotype2(SS2) strain with mrp, sly and ef three known virulent genes,this strain could infect Kunming mice and Newzland rabbits, LD50for Kunming miceand Newzland rabbits were respectively1.6×104CFU and2.0×104CFU. Moreover,animal return test confirmed the strong pathogenicity to weaning pigs, the death rateof weaned pig was5/5.Preparation of the seeds from the isolate and tests of cultural characteristics,immunogenicity and virulence testing of1th generation,9th and13th generationshowed the seeds’stability, provided materials for seeds’ establishment and vaccineresearch and development. We prepared seeds using1th to13th generation strainculture, optimized and studied the fermentation conditions. Research of large-scalefermentation processs and fermentation experiments of the isolate, laid the foundationfor the large–scale production of swine streptococcus antigens.Also, choose formaldehyde as devitalizing agent, according to certain proportionand instruction prepared the inactivated vaccine, after sterility test, security test andrelated tests, when qualified, conveyed immunological protection test using pigletsand New Zealand rabbits as models, respectively the immunological protection were100%and70%; vaccine pigs with negative antibody of Streptococcus, antibody levelsmaintained for more than6months, provided a reliable basis for the application of thevaccine as the antibody ebb using ELISA for antibody detection.