The bacteria that cause acne live on everyone’s skin. Does it mean it’s bad?
Cutibacterium acnes (formerly Propionibacterium acnes/P. acnes) is linked to the skin condition of acne. Its genome has been sequenced and a study has shown several genes can generate enzymes for degrading skin and proteins that may be immunogenic (activating the immune system). We will be referring to the bacteria as P. acnes throughout this manual.
The species is largely commensal and part of the skin flora present on most healthy adult humans’ skin. It is usually just barely detectable on the skin of healthy preadolescents. It lives, among other things, primarily on fatty acids in sebum secreted by sebaceous glands in the follicles. It may also be found throughout the gastrointestinal tract.
Originally identified as Bacillus acnes, it was later named Propionibacterium acnes for its ability to generate propionic acid. In 2016, P. acnes was taxonomically reclassified as a result of biochemical and genomic studies.
Inside the follicles, P. acnes bacteria use sebum, cellular debris and metabolic byproducts from the surrounding skin tissue as their primary sources of energy and nutrients. Elevated production of sebum by hyperactive sebaceous or blockage of the follicle can cause P. acnes bacteria to grow and multiply.
The bacteria secrete many proteins, including several digestive enzymes. These enzymes are involved in the digestion of sebum and the acquisition of other nutrients. They can also destabilize the layers of cells that form the walls of the follicle. The cellular damage, metabolic byproducts and bacterial debris produced by the rapid growth of P. acnes in follicles can trigger inflammation. This inflammation can lead to the symptoms associated with some common skin disorders, such as folliculitis and acne vulgaris.
A study could explain why some people get zits and others don’t. The bacteria that cause acne live on everyone’s skin, yet one in five people is lucky enough to develop only an occasional pimple over a lifetime.
A UCLA study conducted with researchers at Washington University in St. Louis and the Los Angeles Biomedical Research Institute has discovered that acne bacteria contain “bad” strains associated with pimples and “good” strains that may protect the skin. It’s been observed that bacterial strains looked very different when taken from diseased skin, compared to healthy skin. It’s been suggested that a P. acnes strain may protect the skin, much like yogurt’s live bacteria help defend the gut from harmful bugs.
Offering new hope to acne sufferers, the researchers believe that increasing the body’s friendly strain of P. acnes using a simple cream or lotion may help calm spotty complexions.