Detection of the Streptococcus suis of Clinical Healthy Pigs in Chongqing

This research was conducted to investigate the Streptococcus suis carrier state of pigs in Chongqing and reveal the importance of the state in public health.One thousand three hundred and sixty palatine tonsils of clinical healthy slaughter pigs were collected from 17 abattoirs in different district of Chongqing.Streptococcus suis was isolated from the samples.The serotype 1,2,7,9,14 and 1/2 was identified,the virulence-associated genes profile and multilocus sequence typing scheme of which was analyzed.Two hundred and twenty-five strains of Streptococcus suis were isolated from the samples,and the isolation rate was 16.54%.Of the 225 isolates recovered from slaughter pigs,4 Streptococcus suis type 2 isolates,3 Streptococcus suis type 7 isolates,3 Streptococcus suis type 9 isolates were identified and 1 Streptococcus suis type 1/2 isolate was detected.Virulence-associated gene profiling analysis showed that majority isolates(10/11) were defective of some virulence-associated gene;but the isolates possessing all known virulence-associated gene also existed;the short type mrp phenotype Streptococcus suis type 1/2(1 isolate) and type 7(2 isolates) isolates were firstly identified in China.It is obvious that the carrier state of clinical healthy pigs bring potential infection jeopardize to butcher;the prevalent isolates are little different from the other country.