P. acnes bacteria, shown colonizing a blood agar plate, thrive in our pores and can trigger acne.
However, P. acnes phages are a harmless virus on our skin that attacks the P. acnes bacteria and may prove to be an effective treatment against pimples.
Doctors soon may have a new weapon against acne: a harmless virus living on our skin that naturally seeks out and kills the bacteria that cause pimples.
"Acne affects millions of people, yet we have few treatments that are both safe and effective," says principal investigator Robert Modlin, MD, professor of microbiology, immunology and molecular genetics. "A virus that naturally preys on the bacteria that cause pimples could offer a promising new tool against the physical and emotional scars of severe acne."
The findings by scientists at UCLA and the University of Pittsburgh were published in the American Society for Microbiology's journal mBio.
The scientists looked at two microbes that share a big name: Propionibacterium acnes, a bacterium thriving in our pores that can trigger acne, and P. acnes phages, a family of viruses that live on human skin. The viruses are harmless to humans but are programmed to infect and kill the P. acnes bacteria.
Using over-the-counter pore-cleansing strips, the researchers lifted acne bacteria and the P. acnes phages from the noses of both pimply and clear-skinned volunteers. When the team sequenced the phages' genomes, they discovered that the viruses possess multiple features that make them ideal candidates for a new anti-acne therapy.
"Phages are programmed to target and kill specific bacteria, so P. acnes phages will attack only P. acnes bacteria but not others like E. coli," notes Laura Marinelli, PhD, a postdoctoral researcher in Dr. Modlin's laboratory. "This trait suggests that they offer strong potential for targeted therapeutic use."
So why, if the phages naturally attack the P. acnes bacteria, do people still get acne? One hypothesis, the researchers say, is that those with healthy skin may have a population of phages that helps keep the P. acnes bacteria in check, while in others, the phage activity is insufficient to prevent the bacteria from aggravating the immune system.
Acne affects nearly 90 percent of Americans at some point in their lives, yet scientists know little about what causes the disorder and have made narrow progress in developing new strategies for treating it. Dermatologists' arsenal of anti-acne tools - benzoyl peroxide, antibiotics and Accutane - hasn't expanded in decades.
The research team plans to isolate the active protein from the P. acnes virus and test whether or not it is as effective as the whole virus in killing acne bacteria. If laboratory testing proves successful, the researchers will study the compound's safety and effectiveness in combating acne in people.
"Propionibacterium acnes Bacteriophages Display Limited Genetic Diversity and Broad Killing Activity against Bacterial Skin Isolates," mBio, September/October 2012