The little player responsible for acne is known as Propionibacterium acnes, or P. acnes.

Once a hair follicle is plugged and a microcomedo is formed, it becomes a good set-up for the entrance of bacteria. The little player responsible for acne is known as Propionibacterium acnes, or P. acnes. These bacteria are a normal component of human skin, but when sebum starts clogging pores, it allows the bacteria to multiply more than it should. When P. acnes multiples, it leads to inflammation in the skin. The bacteria produce certain enzymes that allow the hair follicle wall to break down and rupture, and there are certain proteins produced by the bacteria that allow tissue damage and inflammation to form. The exact mechanism is complicated, but the end result is what matters -- inflamed, angry, and irritated skin. The fact that bacteria play a role in the development of acne is important, because it allows us to target treatment in very specific manners, including topical and oral antibiotics. It also makes it important for us as doctors and you as patients to try to minimize anything that can lead to the formation of resistant bacteria, both for your health and for the health of others.