Development of a polymerase chain reaction assay for the detection of Listeria monocytogenes in foods

Abstract

Species-specific oligonucleotide primers were selected from the coding region of the listeriolysin O gene of Listeria monocytogenes and were used in conjunction with genus-specific primers and an internal control fragment for polymerase chain reaction amplification. The specificity of the primers was confirmed by testing 40 isolates of L. monocytogenes, other Listeria species and other micro-organisms which are ubiquitous in the environment. The reliability of these primers was further tested in parallel with standard cultural methods. In a preliminary study, over 250 different food samples were examined and PCR results were in complete agreement with those obtained from standard cultural procedures.

Selection of Optimal Primer Sets for Use in a Duplex Sybr Green-Based, Real-Time Polymerase Chain Reaction Protocol for the Detection of Listeria Monocytogenes and Staphyloccocus Aureus in Foods

“…The hlyA primer set anneals to the listeriolysin O gene of L. monocytogenes . This targeted sequence has been reported in several PCR and real‐time PCR applications and uses different primer sequences targeting the same gene (Bansal 1996; Amagliani et al . 2004; Guilbaud et al .…”

Molecular analysis of the iap gene of Listeria monocytogenes isolated from cheeses in Rio Grande do Sul, Brazil

“…All twenty-five positive strains were submitted to PCR with a set of species-specific primers LR/LF to L. monocytogenes by amplification of 750 bp from the hly gene (2).…”

Polymerase chain reaction detection of Listeria monocytogenes using oligonucleotide primers targeting actA gene

“…Many different kinds of methods have been evaluated for detecting or enumerating L. monocytogenes in food samples, including an enzyme-linked immunosorbent assay (Bansal, 1996;Palumbo, Borucki, Mandrell, & Gorski, 2003), culture on selective media, biochemical identification, (Mattingly, Butman, Plank, Durham, & Robison, 1988), DNA-DNA probes (Ninet, Bannerman, & Bille, 1992) and dot-ELISA (Chaudhari, Malik, Rekha, & Barbuddhe, 2001). Cultural methods are simple, but laborious, time-consuming, insensitive and are not suitable for giving the results in the times required by the food industry (de Boer & Beumer, 1999;Klein & Juneja, 1997).…”

“…It is widely diffused in the environment and this fact cause the contamination of food during production and distribution (de Boer & Beumer, 1999;Swaminathan & Feng, 1994). The ubiquitous distribution of this pathogen in nature, its ability to grow at refrigeration temperatures and its tolerance to certain preservative agents make its elimination from food very difficult (Bansal, 1996). Listeria ingested with foods can cause human listeriosis, a serious disease among highrisk populations including pregnant women, unborn children, neonates, the eldly, and immunocompromised individuals.…”