Preparation Of Antisera To Different Serotype Of Streptococcus Suis And Application In The Investigation Of The Bacteria

Streptococcus suis is one the commensal and opportunistic pathogens of swine and prevalent zoonotic agents worldwide.it isα-hemolytic gram-positive cocci with 35 different serotypes.Usually,pig is the healthy carrier of S.suis which exist in the upper respiratory tract(particularly the tonsils and nasal cavities),genital tract and alimentary tract.But in some cases it can cause pneumonia,meningitis,septicemia and arthritis in pigs.In humans, S.suis infection is associated with bacterial meningitis,septic shock,arthritis,pneumonia, endocarditis,endophthalmitis and spontaneous bacterial peritonitis.Among them Meningitis was first recognized in Denmark in 1968.Since then,a lot of cases have been reported in many countries.Now it causes serious lost in our country every year.Moreover,it can cause people to death.In this paper,the epidemic of S.suis was studied in some Provinces of our country.It could provide help to the prevention and cure of S.suis.(1) Preparation and application of Streptococcus suis antisera against 35 serotypes:S. suis reference strains representing capsular types 1 to 34 and 1/2 were used for the production of antisera.Antisera were made with New Zealand White rabbits,Seven days after the last injection,blood samples were taken and detected with tube agglutination test.The results showed that the titers of all the antisera were above 1:32.Cross-absorption could avoid the cross-reaction and increase the sensitivity and specificity of the test.By detecting 12 isolates,the results showed that the antisera could distinguish the serotype 1 and 14,2 and 1/2,which could not be distinguished by PCR.Moreover,serotype 13 was found for the first time in China.(2) Epidemiologic investigation of Streptococcus suis in some provinces of China:In 2006 and 2007,229 isolates were recovered from 1418 samples of Chongqing and Zhejiang, which were detected by PCR.222 S.suis isolates were isolated from 1360 samples of Chongqing in 2006.In 2007,2 S.suis isolates were isolated from 20 samples of Chongqing, and 5 from 20 samples of Zhejiang.The results of multiplex PCR showed that only 18 of the 299 isolates could be identified.These strain were belong to the following capsular types: 1/2(2 strains),2(7 strains),7(4 strains),9(5 strains).(3) Identification the Streptococcus suis isolates from different provinces of China: Tube agglutination was used to identify twenty-six S.suis isolates of Chongqing and Zhejiang,and 23 of the 26 isolates were studied by Multilocus sequence typing(MLST). The tube agglutination results indicate that the most of S.suis isolated from Chongqing were serotype 1/2,2,7,9,15,16,etc.Serotype 2 and 7 existed in Zhejiang.The results of MLST showed that 23 isolates were belong to 14 different STs.