Propionibacterium acnes is a gram-positive bacterium associated with acne and is present on the skin of all people. It causes the appearance of acne vulgaris in 85 to 100% of people at some stage in their lives. The appearance of the famous pimples occurs when a pore is blocked, leading to the growth of P. acnes, which secretes substances that break down the pore wall. This lesion leads to the growth of other bacteria such as Staphylococcus aureus and other contaminating microorganisms, allowing inflammation to occur.
Treatment through topical substances is the most common. They act only on the lesions caused by acne and are palliative in nature. Retinoic acid, for example, is a systemic substance used in the treatment of acne, but its use is highly regulated due to various side effects. The use of systemic antibiotics does not specifically target acne and often leads to a change in the skin's microflora.
Currently, the sequencing of the genome of P. acnes has revealed the existence of genes that encode virulence factors. These virulence factors, such as sialidases, are secreted or anchored in the bacterial cell wall. Sialidases degrade host tissue by cleaving sialoglycoconjugates to release sialic acid, which will be used by the bacterium as a source of carbon and energy. This degradation stimulates sebocytes and keratinocytes, leading to inflammatory responses that promote the appearance of acne. Sialidases have been targeted for vaccines against influenza and bacterial pneumonia.
Recently, a research group from the University of California – San Diego in the United States developed a vaccine against the sialidase of P. acnes. They demonstrated that the vaccine made from a recombinant sialidase was effective in suppressing the inflammation caused by P. acnes in mice.
This result indicates that a vaccine against the bacterium that causes acne could be a hope for people who have already tried various treatments, especially for those who experience side effects from currently available medications.
Reference:
Nakatsuji T, Liu Y-T, Huang C-P, Gallo RL, Huang CM (2008) Vaccination Targeting a Surface Sialidase of P. acnes: Implication for New Treatment of Acne Vulgaris. PLoS ONE 3(2): e1551.
