A pilot study on PCR-based detection of four foodborne pathogenic microorganisms

To establish PCR-based detection methods for Staphylococcus aureus, Shigella, Pasteurella multocida and Pseudomonas aeruginosa, the nuc, ipah, ptfa and oprl genes were amplified by singleplex PCRs and multiplex PCR using specific primers that were designed according to the DNA sequences retrieved from GenBank. Then the annealing temperature was optimized, accompanied by a study of the specificity and sensitivity of the singleplex PCRs and multiplex PCR. The results showed that DNA fragments of 280, 474, 150 and 331 bp were specifically amplified from the four pathogenic bacteria mentioned above. No target DNA fragments were obtained from other pathogenic bacteria, including Salmonella typhimurium, Campylobacter jejuni, Clostridium perfringens and pathogenic Escherichia coli. The sensitivity of the singleplex PCRs were 100, 1, 1 and 10 pg/mu L respectively. The detection limits of the four pathogenic bacteria in the multiplex PCR were 100, 1, 10 and 10 pg/mu L respectively. These results showed that singleplex PCRs and multiplex PCR have good specificity and sensitivity. In conclusion, this experiment has laid a foundation for further research on rapid detection methods against these four pathogenic bacteria in food.