Disease Of Swine Infected With Streptococcus Suis Investigation With Detection Of PCV2 And PRRSV

Streptococcus suis(S.suis)is an extremely important conditional pathogenic bacteria which causes serious infection in many piggeries.Porcine circovirus type 2(PCV2)and Porcine Reproductive and Respiratory Syndrome virus(PRRS)are two important pathogens of immunosuppressive diseases.In this study,correlation between the prevalence of S.suis serotypes,the infection of S.suis and the infection of PRRSV and PCV2 was explored.The main results are as follows:Bacterial isolation and PCR identification were carried out in108 diseased pigs from 45 piggeries,among them,31 pigs from 21 piggeries were isolated from S.suis,the positive rate of swine was 44%,and the positive rate of swine was 28.7%.20 serotypes were detected by the serotype typing analysis of isolated S.suis,where in SS3 accounted for 14.8%,SS2(SS1/2)accounted for 13.9%,SS1(SS14)accounted for 13%,SS31 accounted for 7.4%,SS21 accounted for 6.5%,SS18 accounted for5.6%,the remaining serotypes were less than 5%.Sensitivity test of 12 drugs was carried out in different S.suis serotypes isolated from diseased pig organs,the result shows that the rates of streptomycin,lincomycin,erythromycin and cotrimoxazole(sulfonamides)were 98.6%,97.1%,67.1% and 51.4%,respectively,in 70 strains of S.suis.The sensitivity ratio of several β-lactam drugs was 84.3% ~ 98.6%,the sensitivity ratio of several quinolones was 74.3% ~ 84.2%,and 94.3% of the strains were sensitive to florfenicol.The collection of 108 samples were carried out PRRSV and PCV2 pathogen detection,among them,44 pigs were PCV2 positive pigs,the positive rate was 40.74%;51 pigs were PRRSV positive pigs,the positive rate was 47.2%;24 pigs were both of PCV2 positive pigs and PRRSV positive pigs,the double positive rate was 22.2%.Combined with the isolation of S.suis,we found,PRRSV,PCV2 double negative female pig streptococcus isolation rate of 5/37(14%),PRRSV or PCV2 single infected pig Streptococcus isolate was 10/47(21%),The isolated rate of S.suis was 16/24(67%)in PRRSV and PCV2 double positive pigs.The above results show that:1)The positive rate of S.suis was high in the clinical disease pig organ,which SS1(SS14),SS2(SS1/2),SS3 serotype to occupy the most.2)These S.suis are sensitive to β-lactam,quinolones and florfenicol.3)The isolated rate of S.suis in PRRSV and PCV2 positive samples was higher than that of negative samples,especially in PRRSV and PCV2 double positive pigs,the isolation rate of Streptococcus suis was 66.67%.This study provides a systematic reference for the prevention and control of S.suis.