Tectorigenin combats Salmonella Typhimurium infection through type I fimbriae targeting.

The escalating prevalence of multidrug-resistant Salmonella enterica serovar Typhimurium (S. Typhimurium) necessitates the urgent development of innovative therapeutic strategies. Targeting bacterial virulence factors has emerged as a promising alternative to conventional antibiotics. Among these factors, type I fimbriae serve as essential structural determinants for host colonization and pathogenesis. In this study, we investigated the anti-virulence potential of Tectorigenin (TE), a natural flavonoid isolated from the traditional medicinal herb Belamcandae Rhizoma. Our results demonstrate that TE significantly inhibits swarming motility, biofilm formation, and hemagglutination capacity of S. Typhimurium by directly influence key structural and regulatory genes within the fim operon, including fimA, fimD, fimF, fimH, fimI and the regulator STM0551. In vivo experiments further confirmed that TE treatment alleviates clinical symptoms in S. Typhimurium-infected mice, effectively reducing intestinal inflammation and preserving epithelial barrier integrity. Collectively, these findings highlight TE as a potent anti-virulence agent that targets type I fimbriae, offering a novel non-bactericidal approach for the management of S. Typhimurium infections.