RAPID AND CONCURRENT DETECTION OF LISTERIA SPECIES BY MULTIPLEX PCR

Listeria sps are ubiquitous in nature. Infection due to L. monocytogenes causes illness in animals and humans worldwide. Aim of the present study was to standardize a multiplex PCR for the identification and differentiation of important Listeria species, in particular, Listeria monocytogenes and to detect toxigenic potential of L. monocytogenes. Employing primers for truncated regions of seven genes namely, inlC, llo, iap, prs, mpl, mogR, ispD with an internal amplification control, a novel mPCR was developed. The mPCR was found to be robust and specific when tested against non-listerial organisms. The sensitivity of the assay for detection of Listeria sps in spiked food samples was 102-103 cfu/ml. The assay was evaluated with widely used API listeria kit for identification of 107 Listeria organisms isolated from 238 food/soil samples. The mPCR correctly and promptly identified majority of the isolates. The assay was able to overcome the false positive results of two mutton isolates and two fish isolates that were identified by API listeria kit. Therefore, this mPCR has the potential to be employed as routine food microbiological and epidemiological investigation tool for Listeria sps