Genomic Insights Into the Population and Antibiotic Resistance Changes of <i>Salmonella</i> Pullorum in China

ABSTRACT Salmonella Pullorum is a host‐restricted pathogen that causes substantial economic losses in the poultry industry. This study explores the genomic characteristics of S . Pullorum based on the genomes available on GenBank, with a particular focus on its evolution and antibiotic resistance in China. The analysis reveals that most S . Pullorum strains belong to ST92 and ST2151. The S . Pullorum strains harbor a complex repertoire of virulence genes and nine antibiotic resistance genes (ARGs), including aminoglycoside resistance genes aac (6′)‐ Iaa , aadA5 , aph (3″)‐ Ib , and aph (6)‐ Id ; the tetracycline resistance gene tet (A); sulfonamide resistance genes dfrA17 , sul1 , and sul2 ; and the beta‐lactam resistance gene bla TEM‐1B . The IncX1, IncQ1, and IncN plasmids play significant roles in the co‐transmission of these ARGs. In addition, phylogenetic analysis indicates a closer genetic relationship among S . Pullorum strains isolated from the same country, highlighting the potential regional transmissions. Notably, S . Pullorum strains in China carry a higher number of ARGs than strains from other countries. Evolutionary dynamics reveals that the population size of S . Pullorum in China has stabilized since 2016, while the antibiotic resistance continues to rise. These results underscore the growing risk of S . Pullorum to the poultry industry and public health in China, highlighting the need for ongoing surveillance and effective control measures.