Cutibacterium acnes is one of the most common bacterial species residing on the human skin. Although the pathogenic properties of C. acnes , such as its association with acne vulgaris, have been widely described, its beneficial aspects have not been well characterized.

Cutibacterium acnes plays roles in both acne disease and healthy skin ecosystem. We observed that mutations in the tir-1/SARM1 and p38 MAPK cascade genes significantly shortened Caenorhabditis elegans lifespan upon Cutibacterium acnes SK137 infection. Antimicrobial molecules were induced by SK137 in a TIR-1-dependent manner. These results suggest that defense responses against SK137 involve the TIR-1-p38 MAPK pathway in Caenorhabditis elegans.