Diversity shifts in human gut microbiota induced by Listeria monocytogenes: an in vitro co-culture study

The gut microbiota is a key component of the gut barrier, serving as the first line of defense against foodborne pathogens. However, the specific changes in the gut microbiota upon infection with Listeria monocytogenes remain unclear. This study employed optimized in vitro co-culture methods and high-throughput sequencing technology to investigate the impact of L. monocytogenes on the diversity of the human gut microbiota and its temporal effects. After comparing culture efficacies, the nutrient-rich Gifu anaerobic medium, an initial pathogen concentration of 5 log 10 CFU/mL, and a 36-h co-culture duration were selected. The co-culture results showed that the introduction of L. monocytogenes significantly increased ( P < 0.05) the Shannon index and decreased ( P < 0.05) the Simpson index of the gut microbiota. For the microbiota composition, co-culture significantly increased ( P < 0.05) the abundance of Bacteroidetes at the phylum level, as well as the abundance of Blautia, Ruminococcus_torques_group, Listeria , and Romboutsia at the genus level. PCoA analysis revealed a notable change after co-culturing. No significant differences were observed among the different co-culture time points (12, 24, and 36 h). These findings suggest that L. monocytogenes induced notable changes in human gut microbiota, enhancing both richness and diversity, leading to an increase in certain species. The results will provide critical insights into the role of specific gut microbiota in modulating host responses to L. monocytogenes infection, which could help inform future strategies for preventing or treating foodborne infections and enhancing gut health.