Thursday, 28 January 2021 15:11

P. Acnes is now C. Acnes

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Aesthetics is an ever-changing industry. Skin care professionals must keep abreast of new ingredients, procedures, laws and regulations, the latest research, scientific discoveries, and recent market trends like the microbiome that affect a spa practice. One such change is the renaming of propionibacterium (p.acnes) to cutibacterium (c. acnes).

The percentage of acneic clients that the aesthetician treats varies based on each spa’s specialties, services offered, and marketing practices. Every aesthetician has personally experienced an increase in clients, friends, or family members with outbreaks of maskne due to the onset of COVID-19, which leads to today’s topic – when did p. acnes become c. acnes?

In the basic aesthetic curriculum, skin care professionals learned that acne lesions contain a bacteria called p. acnes. These pathogenic bacteria are rod-shaped, anaerobic, and gram-positive, with a thick cell wall contributing to their resiliency. This bacterium gets its name because of its ability to produce propionic acid, a naturally occurring carboxylic acid. It is liquid in the form of a foul-smell that mimics body odor.

However, skin care professionals are not taught in school that propionibacterium (p. acnes) has 114 different strains that can affect other parts of the body.

Various propionibacterium strains can cause or contribute to chronic blepharitis (inflammation of the eyelids), endophthalmitis (inflammation of the inner-eye, often following cataract surgery),

shoulder infections (usually the following surgery), intestinal issues (can affect the large intestine),

endocarditis (an infection of the endocardium, the inner lining of heart chambers and valves), and

synovitis (inflammation of the membrane that lines the joints found in between bones that move together.) Hyperostosis (bone growth – a form of arthritis), bacterial osteitis (inflammation of the bone), sarcoidosis (an inflammatory disease that develops abnormal masses called granulomas, affecting multiple organs in the body, mainly the lungs and lymph glands), and prostrate inflammation (could lead to cancer) are also contributing.

This list is by no means all-inclusive; however, with 114 different strains, p. acnes affects far more than just the skin.

So, why was propionibacterium renamed now? This is not the first time that the name of this bacteria has changed. Scientific revelations have caused an evolving transformation in the terminology of p.acnes back to the late 19th century.


The pathogenic microorganism, known in medical literature as the “acne bacillus,” was first observed by Paul Gerson Unna M.D., in 1896 under microscopic sections of acne comedones. This was the first modern-day documented connection with the bacteria responsible for acne.

 In 1900, p. acnes was officially identified as Bacillus acnes by Thomas Caspar Gilchrist (honorary) M.D., and in 1923, David Hendricks Bergey, an American bacteriologist, placed “acne bacillus” under the Corynebacterium category, renaming corynebacterium acnes purely based on its similarities to other bacteria in this category. Many years of research continued by bacteriologists and dermatologists alike, with documented studies occurring as long ago as the 1960s.

In 1946, Corynebacterium acnes was transferred to the propionibacterium or p. acnes classification, primarily due to its anaerobic and metabolism properties. It remained there until 2016 when further advances in technology allowed the medical-scientific industry new tools to research and analyze findings.

 In 2016, Christian F. P. Scholz and Mogens Kilian, researchers and professors of medical microbiology proposed the reclassification of this bacteria, based on human genome sequencing technology. Human genome studies are where the knowledge of the microbiome comes from.

From 2016 to 2018 medical providers began using c. acnes (formerly known as p.acnes) in medical papers, articles, blogs, vlogs, webinars, and websites. In late 2018, the publication of the c. acnes terminology became more widespread in the medical community.


Cutibacterium (c.acnes) is defined as a slow-growing, anaerobic, gram-positive bacterium linked to acne. The term cutaneous is derived from the Latin word cutis, meaning the skin. C. acnes is no different from the propionibacterium learned in aesthetic school. It just goes by a new name. It is still a pathogenic, rod-shaped, anaerobic, gram-positive, non-spore producing bacteria. It still proliferates in the lipid-rich environment of the hair follicle using sebum as a source of energy. Advanced technology has allowed descriptions and classifications more accurate, including bacteria types. It is time to spread the word – in the aesthetic community. P.acnes is now known as c.acnes.

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