Color enhanced TEM (transmission electron micrograph) of Propionibacterium acnes, anaerobic gram-positive bacilli responsible for inflammatory acne. P. acnes blocks the hair follicle and can multiply rapidly, blocking the flow of oxygen to the sebaccous gland. As the anaerobic bacteria multiplies, inflammation occurs. Scarring may occur if left untreated. Magnification: 23,000x at 70mm.