Multiplex PCR Assay for Specific, Sensitive and Rapid detection of three food borne pathogens Salmonella sp, Shigella sp and Listeria monocytogenes

Pramod D; Gandhi KH; Ravi Kumar M; Kishore N

Volume : V, Issue : I, January - 2015

Multiplex PCR Assay for Specific, Sensitive and Rapid detection of three food borne pathogens Salmonella sp, Shigella sp and Listeria monocytogenes

Pramod D, Gandhi Kh, Ravi Kumar M, Kishore N

Abstract :

Food–borne illnesses caused by pathogenic bacteria still occur at high frequencies in industrialized nations and developing countries. Conventional microbiological analysis using biochemical tests are time consuming (turn around time up to 7 days), less sensitive and non reliable in most of the cases. This time lag inherent in traditional methods can be replaced by rapid, sensitive detection techniques like multiplex PCR. To achieve an effective detection of Salmonella sp, Shigella sp and Listeria monocytogenes in food materials a multiplex PCR method was standardized in this study. Primers were designed targeting pathogen specific DNA sequence in the genes ipaH, hlyA and sefA of Shigella sp, Listeria monocytogenes and Salmonella sp respectively. Specificity of the primers designed was confirmed by uniplex and multiplex PCR with bacteria (30 different species), fungi and yeast. The multiplex PCR aasay was able to detect all three organisms simultaneously in food materials at a detection sensitivity of 30 ng DNA obtained from each of the three bacteria. Further, the results from examination of food samples from vendor using traditional cultivation methods and multiplex PCR assay were comparatively analyzed. With this assay, simultaneously, all the above three food borne pathogens can be reliably detected with in less than 24 h.