Do Different Strains of Acne Bacteria Affect Acne Differently?

Certain Bacterial Strains Are Present in Different Amounts Between Acne and Non-acne Patients, and These Strains Display Varying Effects on the Immune System, Which Could Affect Acne Development Differently

The Essential Info

Acne is in part a bacterial disease. When it comes to acne, a specific type called C. acnes is the culprit. Scientists found that C. acnes may:

  • Contribute to the formation of clogged pores
  • Cause irritation inside clogged pores once they are formed
  • Cause pimples to become more inflamed, red, and sore

This article is one of the deep science type articles here on Read on if you’re Team Nerd: There are multiple C. acnes strains which are present in different amounts in the skin of acne-prone people. For example, C. acnes type IA1 is present in higher amounts in acne-prone skin than in healthy skin. Further, preliminary research suggests that this strain demonstrates a slightly altered effect on the immune system when compared with other types, and consequently likely contributes to acne development differently.

Research in this area is still in its beginning stages, and scientists will need to perform further research to better characterize the differences among the types of C. acnes as well as other bacterial species, such as Staphylococcus and Klebsiella, to determine how each affects acne development.

The Science

Normally, I’ll try to make articles as understandable as possible. I’ll do that with this one as well, but this is deep science type stuff, so let’s throw caution to the wind and just delve right into all the gory details. Put your thinking cap on and let’s do this!

Many factors lead to the formation of acne lesions, including:

  • Overproduction of skin oil, called sebum
  • Skin cell overgrowth
  • Hormones
  • Bacteria

For the purpose of this article, we’ll focus in on bacteria. It turns out that acne-prone and healthy individuals carry different bacteria and bacterial strains in their skin, only some of which may contribute to the formation of acne. The hope is that if we can discern the exact type of bacteria that is leading to acne symptoms, we can then target it better with treatments.

First, let’s look at the role of acne bacteria, called C. acnes, in acne development.

Role of C. acnes in Acne Development

Cutibacterium acnes (C. acnes) is a single-cell bacterium that is present in both healthy skin and acne-prone skin. It survives using sebum as a source of nutrients, and therefore thrives in clogged pores, where sebum is abundant.

Although scientists previously thought C. acnes was the main cause of acne, recent research found that it is not present in all acne lesions, and therefore is likely to play only a secondary role in acne formation.1 In other words, C. acnes doesn’t cause acne, but it can make acne worse.

Researchers now believe that C. acnes acts to contribute to the worsening of previously formed acne lesions in three main ways.

  1. Producing proteins that adhere to the pore wall. Once the bacterium is stuck to the pore wall, it can better survive and reproduce.2,3
  2. Creating and releasing certain proteins that assist in the degradation of the pore wall, contributing to its rupture and ensuing inflammation.2,3
  3. Stimulating the immune response by triggering the release of inflammatory molecules, which results in inflammation. One main class of inflammatory molecules that C. acnes releases is called CAMP (Christie, Atkins, Munch, Peterson) factors. CAMP factors are able to puncture immune cells, resulting in immune cell death, toxicity, and release of additional inflammatory molecules that worsen inflammation.2-4
Role of P. acnes in Acne Development

Bacterial Strains of C. acnes and Acne Development

Scientists classify bacteria of the same species into small subgroups called strains. To group bacteria into strains, scientists sequence the bacterial genome and group bacteria into strains if they have at least 95% identical DNA. There are about 100 strains of C. acnes that fall into the following three main groups:

  • Type I – present in skin with acne
  • Type II – not present in skin with acne
  • Type III – not present in skin with acne

Type I contains the additional four strains:5

  • Type IA1 – most abundant in acne-prone skin
  • Type IA2
  • Type IB
  • Type IC

Scientists have performed four independent studies to identify if the different strains present in the skin influence acne development differently. All four studies found that type IA1 is more abundant in acne-prone skin than in healthy skin.6-9

Further, one of the studies found that type II bacteria were not present in skin samples taken from skin with acne, and another study showed that the same was true of type III bacteria. But in both studies, type II and type III bacteria made up around 20% of all bacteria in the healthy skin samples.7,9

Types of C. acnes Bacteria

With the knowledge that type IA1 is more abundant in acne-prone skin than in healthy skin, scientists have performed four studies to classify if this particular strain of C. acnes contributes to acne development in a unique way. 

Results of these studies show that type IA1may be better able to survive inside clogged pores, which explains why we see them more often in acne-prone skin. Also, type IA1may provoke the immune system in different ways than the other strains, but researchers need to perform more research to understand exactly how this affect acne development.

Expand to read details of study

A 2005 study found that C. acnes type IA1 produced much lower levels of CAMP-1 than types IB and II, but higher levels of CAMP-2 than type II. Although it remains unclear how this affects the inflammatory response, this study concluded that different C. acnes types could provoke unique immune responses.10

BMC Microbiology

A 2010 study discovered that C. acnes type IA1 produced more follicular adhesion proteins, which likely helps the bacteria stick better to the follicular (pore) wall, thus promoting clogged pores.11

Experimental Dermatology

A 2013 study examined the immune system response to C. acnes in laboratory-grown human cells. They used their data to order the C. acnes types by strongest immune response (type III) to weakest immune response (type IB). They found that the order of immune system response from strongest to weakest is type III, II, IC, IA1, and IB. Further, the scientists found that each C. acnes type stimulated the release of different inflammatory molecules called cytokines, which in theory could stimulate unique immune system responses.12

International Journal of Medical Microbiology

A 2018 study published in the International Journal of Medical Microbiology looked at the ability of different C. acnes strains to form biofilms.13 A biofilm is a large cluster of bacteria embedded into a sugar matrix produced by the bacteria themselves. Bacteria living in biofilms are more resistant to antibiotics and more likely to trigger inflammation than bacteria living on their own. Research shows that people with acne tend to have significantly more C. acnes biofilms in their skin pores than people without acne.14

This study found that C. acnes type IA1 bacteria were 2-8 times better at forming biofilms compared to other strains.13 Since biofilms help acne bacteria to survive and to stimulate more inflammation, this may make type IA1 bacteria especially problematic for people with acne.

What We Know About the Different C. acnes Strains

Other Bacterial Species in Acne Development

Other Bacteria Associated with Acne

Although scientists have focused their acne development research on C. acnes, there is a variety of bacterial species present in the skin that also may affect acne formation.

  • Researchers found that the presence of Staphylococcus epidermidis (S. epidermidis) is increased by 70% in acne-prone skin. Further, research shows that S. epidermidis secretes factors that can worsen pore clogging.
  • It also was noted that Staphylococcus aureus (S. aureus) is present at higher levels in many skin disorders, including acne. Scientists believe that S. aureus may produce proteins that aid in pore wall rupture.
  • In addition, researchers found Staphylococcus pyogenes (S. pyogenes) in the oropharynx (region including the back of the throat and tongue) in acne-prone individuals but not healthy individuals. It is not yet clear how bacteria present in the oropharynx affects the development of acne.
  • Klebsiella pneumoniae (K. pneumoniae) also was found in acne lesions, but not in healthy skin.
  • Streptococcus agalactiae (S. agalactiae) produces factors that are similar to those of C. acnes and may be involved in acne development.1
Petri Dish with Bacteria Associated with Acne

The research into the specifics of various bacteria strains is an exciting area of exploration. However, it is just getting underway. Scientists have performed scarce research examining the various roles these bacteria play in acne development, and therefore researchers must perform more studies to confirm these associations.

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  2. Kumar, B. et al. New insights into acne pathogenesis: Exploring the role of acne-associated microbial populations. Dermatol Sinica 34, 67 – 73 (2016).
  3. Brüggemann, H. et al. The complete genome sequence of Propionibacterium acnes, a commensal of human skin. Science 305, 671 – 673 (2004).
  4. Nakatsuji, T., Tang, D. C., Zhang, L., Gallo, R. L. & Huang, C. M. Propionibacterium acnes CAMP factor and host acid sphingomyelinase contribute to bacterial virulence: Potential targets for inflammatory acne treatment. PLoS ONE 6, e14797 (2011).
  5. Yu, Y. et al. Typing of Propionibacterium acnes: a review of methods and comparative analysis. Br J Dermatol 172, 1204 – 1209 (2015).
  6. Lomholt, H. B. & Kilian, M. Population genetic analysis of Propionibacterium acnes identifies a subpopulation and epidemic clones associated with acne. PLoS ONE 5, e12277 (2010).
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  8. McDowell, A. et al. The opportunistic pathogen Propionibacterium acnes: Insights into typing, human disease, clonal diversification and CAMP factor evolution. PLoS ONE 8, e70897 (2013).
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  10. Valanne, S. et al. CAMP factor homologues in Propionibacterium acnes: a new protein family differentially expressed by types I and II. Microbiology 151, 1369 – 1379 (2005).
  11. Holland, C. et al. Proteomic identification of secreted proteins of Propionibacterium acnes. BMC Microbiol 10, 230 (2010).
  12. Jasson, F. et al. Different strains of Propionibacterium acnes modulate differently the cutaneous innate immunity. Exp Dermatol 22, 587 – 592 (2013).
  13. Kuehnast, T., Cakar, F., Weinhäupl, T., Pilz, A., Selak, S., Schmidt, M. A., Rüter, C. & Schild, S. Comparative analyses of biofilm formation among different Cutibacterium acnes isolates. Int J Med Microbiol 308, 1027-1035 (2018).
  14. Dréno, B., Pécastaings, S., Corvec, S., Veraldi, S., Khammari, A. & Roques, C. Cutibacterium acnes (Propionibacterium acnes) and acne vulgaris: a brief look at the latest updates. J Eur Acad Dermatol Venereol 32 Suppl 2, 5-14 (2018).