Scientists in the US have demonstrated the effectiveness of 11 phages (viruses that infect bacteria) living on our skin that naturally seek and destroy Propionibacterium acnes, the bacterial culprit behind acne.
Phage-based antimicrobial acne treatment
The research, published in the September/October 2012 edition of mBio, the journal of the American Society for Microbiology, says there is potential to harness the viruses to produce a safe and effective phage-based antimicrobial treatment for acne. The researchers found that the viruses possess multiple features – such as small size, limited diversity and the broad ability to kill their hosts – that make them ideal candidates.
Using over-the-counter pore-cleansing strips from the pharmacy, the team lifted the acne bacterium and the P. acnes viruses from the noses of both acne-affected and clear-skinned volunteers. They identified the phages and grew isolates of the bacterium in the lab. They then found they were able to kill the isolates by infecting them with the phages.
Similarity of phages’ genomes
The phages’ genomes were sequenced, allowing the researchers to see that the 11 identified phages were very similar. Corresponding author Professor Graham Hatfull at the University of Pittsburgh said in a Pitts release, “The lack of genetic diversity among the viruses that attack the acne bacterium implies that viral-based strategies may help control this distressing skin disorder.”
One of the authors, Laura Marinelli, a UCLA postdoctoral researcher, said in a press release from UCLA that,while they know that sex hormones, facial oil and the immune system play a role in causing acne, a lot of research implicates P. acnes as an important trigger.
Why acne affects some and not others
Dr Marinelli noted that the phages they studied are programmed “to target and kill specific bacteria, so P. acnes phages will attack only P. acnes bacteria but not others like E. coli.” This trait makes the viruses harmless to humans or indeed to anything except P. acnes. So why do some people still get acne if these viruses exist? In their research report,the authors hypothesise that those with healthy skin may have a sufficient population of phages that helps keep the P. acnes bacteria in check, while in others, phage activity is insufficient to prevent the bacteria from aggravating the immune system.
The researchers note that,although acne affects most people at some point in their lives, scientists have made narrow progress in developing new strategies for treating it. The dermatologists’ arsenal of anti-acne tools –benzoyl peroxide, antibiotics and Accutane –hasn’t expanded in decades.
Acne’s resistance to antibiotics
In the UCLA release, Dr Jenny Kim, co-author and director of the UCLA Clinic for Acne, Rosacea and Aesthetics, noted, “Antibiotics such as tetracycline are so widely used that many acne strains have developed resistance, and drugs like Accutane, while effective, can produce risky side effects, limiting their use. Acne can dramatically disfigure people and undermine their self-esteem, especially in teens. We can change patients’ lives with treatment. It’s time we identified a new way to safely treat the common disorder.”
Isolating the active protein
The research team plans to continue its research by isolating the active protein from the P. acnes viruses and testing whether it is as effective as the whole viruses in killing acne bacteria. If laboratory testing proves successful, the researchers will study the safety and effectiveness of the compound they develop in combating acne in people. It’s possible that an isolated enzyme used by the viruses to break down the bacterial cell wall and escape (thereby killing its host) could become the basis of an easy smear-on treatment in the not-too-distant future.