Rapid molecular identification of Listeria species by use of real-time PCR and high-resolution melting analysis

Identification of Listeria species via a molecular method is critical for food safety and clinical diagnosis. In this study, an assay integrating real-time quantitative PCR (Q-PCR) with high-resolution melting (HRM) curve analysis was developed and assessed for rapid identification of six Listeria species. The ssrA gene, which encodes a transfer-messenger RNA (tmRNA) is conserved and common to all bacterial phyla, contains a variable domain in Listeria spp. Therefore, Q-PCR and a HRM profile were applied to characterize this gene. Fifty-three Listeria species and 45 non-Listeria species were detected using one primer set, with an accuracy of 100% in reference to conventional methods. There was a 93.3% correction rate to 30 artificially contaminated samples. Thus, Q-PCR with melting profiling analysis proved able to identify Listeria species accurately. Consequently, this study demonstrates that the assay we developed is a functional tool for rapidly identifying six Listeria species, and has the potential for discriminating novel species food safety and epidemiological research.