Implementation and Comparison of Real-Time Molecular Serotyping and Conventional PCR for Listeria monocytogenes Strains in Food

Abstract

Listeria monocytogenes is an important foodborne pathogen responsible for listeriosis, a severe human infection with high morbidity and mortality. Molecular serotyping is a universally accepted subtyping method for L. monocytogenes. Identification of strain serotype permits differentiation between significant foodborne strains (1/2a, 1/2b, and 4b) and allows a better understanding of their distribution and epidemiological significance. This study evaluated the implementation of real-time molecular serotyping of L. monocytogenes and compared its performance with conventional PCR methods. Eighty L. monocytogenes strains isolated from food and the food chain were analysed. Conventional multiplex PCR and qualitative real-time PCR (ReT-PCR) were used to identify molecular serogroups based on specific genetic markers to define the presence or absence of a particular serogroup of L. monocytogenes in strains. The results showed that ReT-PCR offers faster processing times than the conventional method. These strains belonged predominantly to serogroup IIa, followed by IIc, IIb, and IVb. ReT-PCR is becoming a standard tool for the detection and expression profiling of selected strains. This research highlights the importance of providing a rapid method for the qualitative detection of L. monocytogenes in food and integrating ReT-PCR into routine diagnostic applications.