Population dynamics and genomic characterization of Salmonella Infantis reveal poultry as a major reservoir of antimicrobial resistance genes and pESI megaplasmid

Foodborne illness caused by Salmonella remains a major public health concern. Among >2,500 known Salmonella serovars, S. Infantis ranks among the top 10 serovars causing human illness. The significance of S. Infantis is further amplified by its ability to harbor and disseminate antimicrobial resistance (AMR) genes mediated by pESI-like megaplasmid. Therefore, understanding the population dynamics and assessing the risk of AMR gene carriage in S. Infantis isolates collected from diverse sources and geographic locations are critical. The findings from this analysis help identify high-risk reservoirs and track current AMR trends, enabling the development of streamlined treatment strategies and data-driven interventions aimed at limiting the global spread of multidrug-resistant S. Infantis.