Scientists have discovered there are “bad” strains of acne bacteria associated with pimples and “good” strains that may protect the skin.
Acne-causing bacteria live on everyone’s skin, yet one in five people only gets an occasional pimple over a lifetime.
The findings, published in the Journal of Investigative Dermatology, could lead to new therapies to prevent and treat the disfiguring skin disorder.
“We learned that not all acne bacteria trigger pimples—one strain may help keep skin healthy,” says lead author Huiying Li, an assistant professor of molecular and medical pharmacology at the David Geffen School of Medicine at University of California, Los Angeles.
“We hope to apply our findings to develop new strategies that stop blemishes before they start and enable dermatologists to customize treatment to each patient’s unique cocktail of skin bacteria.”
The scientists looked at the tiny microbe Propionibacterium acnes, a type of bacteria that thrives in the oily depths of our pores. When the bacteria aggravate the immune system, they cause the swollen, red bumps associated with acne.
Using over-the-counter pore-cleansing strips, researchers from Los Angeles Biomedical Research Institute and UCLA lifted P. acnes bacteria from the noses of 49 pimply and 52 clear-skinned volunteers.
After extracting the microbial DNA from the strips, the scientists tracked a genetic marker to identify the bacterial strains in each volunteer’s pores and recorded whether the person suffered from acne.
Washington University scientists sequenced the genomes of 66 of the P. acnes strains, enabling the team to zero in on genes unique to each strain.
“Our research underscores the importance of strain-level analysis of the world of human microbes to define the role of bacteria in health and disease,” says co-author George Weinstock, associate director of The Genome Institute and professor of genetics at Washington University in St. Louis.
“This type of analysis has a much higher resolution than prior studies that relied on bacterial cultures or only made distinctions between bacterial species.”
The researchers wanted to learn whether the bacterial strains looked notably different when they were taken from diseased skin, compared with healthy skin.
“Two unique strains of P. acnes appeared in one out of five volunteers with acne but rarely occurred in clear-skinned people,” says co-author Noah Craft, a dermatologist and director of the Center for Immunotherapeutics Research at LA BioMed at Harbor-UCLA Medical Center.
The biggest discovery was still to come.
“We were extremely excited to uncover a third strain of P. acnes that’s common in healthy skin yet rarely found when acne is present,” says Li. “We suspect that this strain contains a natural defense mechanism that enables it to recognize attackers and destroy them before they infect the bacterial cell.”