P. Acnes: Bothersome Breakouts

P. Acnes: Bothersome Breakouts

Is P. Acnes just a prevalent adolescent pang?

Or a life-long skin challenge? Well, it turns out it could be both.

Acne is mostly associated with hormonal teens, yet adults can also find themselves with acne symptoms.

Clinical studies have found, some 40 percent of the adult population between the age of 20 to 40 have been diagnosed with lower acne grade.

In order to understand this tricky little bacteria, we need to first understand its anatomy.

What is P. acnes?

P. acnes are a type of “gram-positive” bacteria, that have thick cell walls that help protect them from their environment.

This bacteria grows deep within the pores, where it feeds on oil or sebum that is produced by the sebaceous glands that surround the base of the pore.

What we do know is that most people with acne symptoms have an overgrowth of P. acnes bacteria on their skin and that this specific strain of P. acnes bacteria is commonly associated with acne vulgaris.

There are many other types of gram-positive bacteria that cause infections, such as Staphylococcus and Corynebacterium which can also reside in the skin and contribute to acne breakouts.

P. acnes is an anaerobic bacteria that likes to grow in low oxygen environments – such as deep within a plugged follicle, where it forms sticky clumps of bacteria known as biofilms that help them to attach to surfaces and change their environment.

These bacterial biofilms have been shown to contribute to long term infections and may play a role in the persistence of P. acnes infection in some individuals.

P.Acnes bacteria love oil

Oil in the skin is created by sebaceous or oil glands, found within our pores, this type of environment contains triglycerides; oil-rich fatty acids, usually, these fatty acids are our skin’s best friend, helping to maintain the pH value of our skin’s acid mantle

Too many fatty acids can be mistaken for foreign bodies within the sebaceous gland, triggering an anti-inflammatory reaction which excites the oil-loving bacteria, creating inflammation.

The bacteria happily go about their business, converting fatty acids and creating an inflammatory response in the pore. They just love that oil-rich environment and the warmer and oilier it gets, the more active the bacteria becomes. This is what ultimately causes breakouts and associated with the skin.

Enzymes aren’t always friends

As if that isn’t enough, the P. Acnes bacteria release protein-digesting enzymes known as proteases, these enzymes penetrate the dermis, the second layer of skin, which triggers an inflammatory response within the skin – causing acne breakouts.

The fatty acids also release a chemical messenger, which attracts a type of white blood cell that releases an enzyme to break down the cell wall.

This article is an interesting read if you want to discover more about the role of acne on the skin.


A comparative study of Cutibacterium (Propionibacterium) acnes clones from acne patients and healthy controls. Lomholt, et al. 2017.
Propionibacterium acnes: an update on its role in the pathogenesis of acne. Beylot, et al. 2014.
Antagonism between Staphylococcus epidermis and Propionibacterium acnes and its genomic basis. Christensen, et al. 2016.

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