Sunday, 3 March 2013

Propionibacterium acnes and clear skin

The pore-dwelling bacterial species Propionibacterium acnes has long been associated with acne. However, whilst some strains of the bacterium are associated with pimples, investigators have found another strain is associated with clear skin, according to a study published in the Journal of Investigative Dermatology.

Propionibacterium acnes is the relatively slow-growing, typically aerotolerant anaerobic, Gram-positive bacterium (rod) linked to the skin condition acne; it can also cause chronic blepharitis and endophthalmitis. This bacterium is largely commensal and part of the skin flora present on most healthy adult humans' skin. P. acnes bacteria live deep within follicles and pores, away from the surface of the skin. In these 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 glands (sebaceous hyperplasia) or blockage of the follicle can cause P. acnes bacteria to grow and multiply.

P. acnes 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.

The authors of the new study used pore-cleansing strips to collect samples at clinics in California from 101 peoples’ noses, half with acne and half with clear skin. They confirmed that P. acnes was the dominant species in the pores and found that overall levels of the bacteria did not vary significantly based on whether subjects had acne or not. However, people without acne tended to harbor the strain RT6, while the acne-ridden were strongly associated with the strains RT4 and RT5.

The study could have significant implications for acne treatment.



Posted by Tim Sandle

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