P. acnes (Propionibacterium acnes) is the most common Gram-positive, non-spore forming, anaerobic rod and a major inhabitant of adult human skin, where it resides within sebaceous follicles, usually as a harmless commensal, even though it has been implicated in Acne Vulgaris (Pimples) formation. P. acnes typically grows as an obligate anaerobe, however, some strains are aerotolerant, but still show better growth as an anaerobe. It has the ability to produce Propionic acid and Catalase along with Indole, Nitrate, or both Indole and Nitrate. The bacteria release Lipases to digest a surplus of the skin oil, Sebum. The combination of digestive products (Fatty acids) and bacterial antigens stimulates an intense local inflammation that bursts the hair follicle. Then, a lesion forms [...]