Comparative Mechanisms of Different Bifidobacteria in Combating Pathogen Infection and Prolonging the Lifespan in Caenorhabditis elegans.

The research employed Caenorhabditis elegans to compare the anti-infection and lifespan-extending properties of Bifidobacterium. The results demonstrated that BL-99 and YLGB-1496 intervention improved the nematodes' resistance to Staphylococcus aureus infection, resulting in lifespan extensions of 5.90% and 14.38%, respectively, accompanied by the alleviation in the decline of pharyngeal pumping rate and locomotor capacity. Furthermore, both probiotic strains significantly extended the mean lifespan of nematodes by 10.96% and 12.14%, and significantly alleviated pharyngeal pumping and locomotion. Importantly, BL-99 and YLGB-1496 have different underlying mechanisms of action. Transcriptomic analyses indicated that the BL-99 strain enhanced nematode resistance to Gram-positive pathogens through the upregulation of lysozyme, saposin-like antimicrobial peptides, and c-type lectin family genes. Conversely, YLGB-1496 improved the epidermal permeability barrier by upregulating genes involved in collagen synthesis and assembly. Overall, this study provides novel insights into the species-specific effects of Bifidobacteria on pathogen resistance and lifespan extension.