Listeriolysin O Gene-Based Detection and Phylogenetic Investigation of <i>Listeria monocytogenes</i> in Food and Environmental Samples

Background and Aim: Listeria (L.) monocytogenes is a foodborne pathogen found in various environments including water, soil, and food.Due to the high importance of this bacterium in public health and the potential differences between its lineages in pathogenicity, this study aimed to investigate and identify the phylogenetics of Listeria in food and environmental samples based on Listeriolysin O gene.Materials and Methods: About 100 samples were collected from Shahriar and Andisheh counties, Iran in summer and fall.After the enrichment and cultivation on selective agar, the suspicious colonies were purified.Lineage identification was performed using mismatch amplification mutation assay-polymerase chain reaction (MAMA-PCR) specifically for Listeriolysin O gene.Data were analyzed using GraphPad Prism.Results: Of 100 samples examined, 22 samples (22%) showed contamination with L. monocytogenes.Of these, 16 (72.7%)belonged to lineage II, one (4.5%)belonged to lineage III, and the remaining 5 (22.7%) did not belong to any of the three lineages studied.Moreover, three positive samples were related to the environmental samples (water and soil). Conclusion:The study showed lineage II as the most common lineage in the examined samples.Moreover, the results emphasized the importance of monitoring L. monocytogenes contamination in food and environment to improve control strategies and ensure food safety.