The Epidemiological Investigation And Development Of Multipex PCR For Detection Of Streptococcus Suis In Loudi

Streptococcus suis is a Gram-positive bacterium of the 33different serotypes identified that infects pigs and can occasionally cause serious infections in humans. Moreover,it is caused huge economic losses to the swine industry, has also been listed as the 2 types of Chinese animal epidemics as zoonotic pathogens. Because of the complex of serum type, it is often difficult to diagnose. The clinical symptoms caused by it are also varied, such as acute sepsis, meningitis, endocarditis, pneumonia and arthritis. At present, the world has more than 30 countries reported swine or human Streptococcus suis infection, however, to understand the distribution of Streptococcus suis, is not only in order to clarify the situation is more popular nowadays,and to assess the current popular area.This study carried out a serotype survey of SS prevalent in different areas of Loudi city, and according to Streptococcus suis prevalent in the areas of Loudi city to development of multiple PCR assay in order to provide scientific basis for the prevention of swine streptococcosis.An enrichment culture, Gram's staining and microscopy, and PCR was implemented from 400 samples of nosal swabs collected from clinical healthy pigs in Xinhua, Lianyuan, Lengshuijiang,Shuangfeng and Louxingqu of Loudi city. The results showed that 239 of 400 isolates were SS isolated from the samples, and of them,the 21 different serotypes identified. It contains SS1?SS2?SS3?SS4?SS5?SS7?SS8?SS10?SS11?SS13?SS15?SS17? SS18?SS20?SS21?SS23?SS26?SS28?SS29?SS30?SS31,in which decreasing order of Positive rate:8.25% belonged to SS3,6.75%was SS2,5.75%was SS8,4.75%was SS7, 4.50%was SS23,3.75%was SS21,3.25%was SS10,4.25%was SS9,2.00%was SS1,1.50% was SS26 and 1.00%was SS11.It suggesting that there are various complex serotypes of SS in clinical healthy pigs.According to the epidemiological investigation of Loudi city, development of multiple PCR assay for SS3, SS8, SS21, SS23. Refer to the GenBank sequence, according to the specific gene of Streptococcus suis (capsular polysacchride, CPS3L, CPS8K,CPS21I, CPS23I respectively for SS3, SS8, SS21, SS23) 4 primers were designed and synthesized, expected amplified fragment size were 210,278,618,487bp. By setting the Pasteurella, e.rhusiopathiae, Staphylococcus aureus, Escherichia coli and water to verify the specificity of the multiplex PCR. Accuracy was verified by standard strains of SS3, SS8, SS21, SS23. Gradient dilution of template to determine the sensitivity of multiplex PCR. The results show that the multiplex PCR in the annealing temperature of 55? can be amplified 4 bands of the expected size. The specificity and accuracy of the method were expected to coincide with the sensitivity of 1.2×102CFU/Ml. The results of the 5 experiments were in agreement with the experimental results. The multiple PCR method established the efficient for the monitoring of Loudi City Pig Streptococcus suis epidemic situation.