Researchers reveal correlation between ribotype (RT) strains of Cutibacterium acnes, which are found in human skin, and the lifespan of the nematode Caenorhabditis elegans. Strains RT4 and 8, which are associated with acne in human skin, shortened the lifespan of the nematode, while RT6, which are predominantly found in healthy human skin, did not. Also, it was found that the healthy skin-related RT6 strain of C. acnes improved C. elegans resistance to the pathogenic organism Staphylococcus aureus.