Unbalanced Skin Microbiome May Be Key to Acne Development, Study Finds
The overall balance of the bacteria on a person’s skin, rather than the presence or absence of a particular bacterial strain, appears to be an important factor for acne development and skin health, according to a study published recently in the journal Scientific Reports .
This micrograph depicts the gram-positive bacterium Propionibacterium acnes grown in thioglycollate medium at 48 hours. Propionibacterium acnes is a very common obligate anaerobic, non-spore forming rod, and the etiologic pathogen responsible for acne vulgaris, or pimples. It normally resides in the sebaceous glands of the skin. Image credit: Bobby Strong, CDC.
The skin — the human body’s largest organ — functions as the first line of defense by providing a protective barrier between the environment and inner body.
It harbors several hundreds of resident microorganisms, which function in communities and protect the body from invasion of pathogens.
Acne vulgaris — commonly called acne — is the most common skin disease, affecting 80–85% of the population. It is most prevalent in adolescents and rarely occurs in people over the age of 50.
While acne is a disease of hair follicles on the skin, the exact causes of the condition are unclear.
Propionibacterium acnes has long been associated with acne, but with this bacterium being the most prevalent and abundant species in the follicle in both healthy and acned individuals, its role in acne has not been well understood.
In a recent study on acne, a team of researchers at the University of California, Los Angeles (UCLA), used over-the-counter pore cleansing strips to obtain skin follicle samples from 72 individuals: 38 with acne and 34 who didn’t have the disease.
The scientists then used a technique called DNA shotgun sequencing analysis to identify and compare the make-up of the skin microbiome of the two groups, and further validated the findings in an additional 10 individuals.
They were able to detect differences in skin bacteria composition, pinpointing fine genetic differences between the Propionibacterium acnes strains of the two clinical groups.
In the healthy group, the bacterial community was enriched with genes related to bacterial metabolism, which are thought to be important in preventing harmful bacteria from colonizing the skin.
“In acne patients, the microbiome composition at the species level and at Propionibacterium acnes strain level was more diverse than in healthy individuals, with enriched virulence-associated factors and reduced abundance of metabolic synthesis genes,” the researchers said.
“Based on the abundance profiles of the metagenomic elements, we constructed a quantitative prediction model, which classified the clinical states of the host skin with high accuracy in both our study cohort (85%) and an independent sample set (86%).”
“This study suggests that the make-up of the bacteria in the follicles can reflect, as well as influence, the skin condition in acne or healthy skin,” said study lead author Dr. Huiying Li, from the David Geffen School of Medicine at UCLA.
“The work provides new insights into the microbial mechanisms behind acne development and suggests that targeted treatments to modulate the skin microbiota and maintain a healthy bacterial balance may be preferable over antibiotic usage, which can unselectively kill both harmful and beneficial skin bacteria.”
“These treatments could include probiotic supplementation or phage therapy that selectively targets specific bacterial strains.”