Abstract:
Salmonella enterica serovar Typhimurium (S. Typhimurium) is a major foodborne pathogen that can cause severe gastroenteritis in humans. Pig is an important natural reservoir and an essential source of human salmonellosis infections worldwide. Understanding the genetic basis of S. Typhimurium adaptation and colonization within the pig is key for developing effective interventions for controlling salmonella in pork production systems and reducing human infections. In this study, we performed whole genome sequencing of 200 S. Typhimurium isolates obtained from different sources along the pork production chain including pig farms, slaughterhouses and pork products. Comparative genomic analysis revealed the presence of distinct genomic variants associated with each stage of the production chain, highlighting the ability of the bacteria to adapt to the different environmental conditions. Isolates harboring specific virulence genes, such as those involved in intestinal invasion and systemic spread, were found to be more prevalent in pigs than in other sources, indicating the selective advantage of these genes for survival and persistence within the host. Additionally, we identified genomic islands unique to S. Typhimurium isolates from pigs that could contribute to their adaptation and colonization in this host species. These findings provide new insights into the genetic mechanisms of salmonella host adaptation and persistence, and identify potential targets for controlling salmonella in pork production and reducing the risk of human infection.
