Infection strategies of <i>Salmonella</i> Typhimurium for gut-lumen colonization: Overcoming host defenses, exploiting host responses, and adapting to the enteric niche

Diarrheal disease is a leading cause of child morbidity and mortality globally, largely resulting from contaminated food and water and exposure to enteric pathogens. Salmonella enterica serovar Typhimurium (STm) is an enteropathogenic bacterium that infects the gastrointestinal tract using diverse strategies that are still being elucidated. Meanwhile, the gut comprises a complex ecosystem known as the microbiome, which is densely inhabited by microbial communities. The microbiome confers colonization resistance against enteropathogenic bacteria, whereas STm can overcome these defenses to establish infection. Here, we review STm infection strategies in the gut, with a particular focus on evidence from mouse models. Understanding STm virulence mechanism and adaptation strategies may inform the development of targeted interventions to prevent and treat gastrointestinal infection.