Strain-specific interactions between Listeria monocytogenes and Salmonella typhimurium in co-culture conditions

Introduction & Aim: Listeria monocytogenes is a foodborne pathogen associated with listeriosis, a severe infection with high mortality rates, especially among high-risk groups including the elderly, pregnant women, neonates, and immunocompromised individuals[1]. Within the human gastrointestinal tract, colonization by L. monocytogenes is challenged by several defense mechanisms, among which the gut microbiota plays a pivotal role in suppressing pathogen overgrowth and invasion[2]. This study aimed to assess the interactions between L. monocytogenes and Salmonella enterica serovar Typhimurium, a facultative pathogen that can transiently inhabit the human gut, to better understand how microbial competition may influence Listeria survival and behavior. Conclusion and Relevance: The results indicate that interactions between L. monocytogenes and S. Typhimurium are strain-dependent, with strain 2606 being more adversely affected by co-culture. These findings underscore the importance of microbial competition in shaping pathogen behavior in the gut environment. Future research will broaden this investigation by including a larger set of L. monocytogenes strains and co-culturing them with additional gut-associated bacteria to gain deeper insights into ecological interactions influencing pathogenicity and survival.