Establishment and application of multiplex real-time PCR to detect Streptococcus suis serotype 2

A rapid multiplex real-time polymerase chain reaction(PCR) for detection of Streptococcus suis serotype 2 was established in this study. Primers and taqman probes were designed according to cps2I (capsular polysaccharide 2I) and mrp (muramidase released protein) genes with primer express 2.0. Multiplex real-time PCR amplifying curve showed that this method could successfully amplify Streptococcus suis serotype 2, but reference Streptococcus suis strain, E.coli, Salmonella, Staphylococcus aureu, Shigella, Listeria monocytoge and blank control were all negative. 10-fold dilution of Streptococcus suis serotype 2 were used to measure the sensitivity of multiplex real-time PCR. 10 bacteria could be detected in one PCR reaction. To examine the stability of the multiplex real-time PCR, positive control was detected at two different times with 20 repeats of each. Results showed that Ct number of two times have no statistic difference (P0.05), thus this method has a reliable stability. This reaction can be completed within 60 min. The newly-built multiplex real-time PCR has high sensitivity, good specificity, reliable stability, so it has potential to apply in entry-exit inspection and quarantine.