This article originally appeared on TonicDespite being a scourge for many teenagers, acne isn't completely understood among scientists. It's a disease affecting hair follicles on the skin, but it's not clear what exactly causes the condition. New research, though, suggests acne may be caused by the balance of bacteria on your skin.So let's start there: Everyone's skin hosts a collection of bacteria in what's known as a microbiome. (Microbiomes are everywhere, including in your showerhead.) Within that facial microbiome is Propionibacterium acnes, a bacteria long associated with acne. Yet P. acnes is also found on healthy skin free of breakouts; in fact, it's the most prevalent and abundant species, further complicating the question of whether—and how—it causes acne.The new findings, presented at the annual conference of the Microbiology Society in Edinburgh, Scotland, suggest the bacteria comes in two strains, with subtle differences at the genetic level. The P. acnes strain found on people without acne has genes that scientists believe help prevent bacteria from colonizing the skin. But among people who do have acne, P. acnes has higher levels of genes associated with virulence; this strain may be more likely to produce and transport bacterial toxins that can harm the skin and cause inflammation.The scientists discovered these differences by examining pore-cleansing strips, which gave them skin follicle samples to test. Using DNA sequencing to compare samples from those with acne to those without, they linked one strain of P. acnes to the disease. They could then reverse the process, sequencing samples and accurately predicting whether they came from acned skin.Right now, the research, which was an update to a paper published in December, has only been presented at a conference; it hasn't yet undergone peer review. But if the findings hold, they'll suggest a new way to treat acne. The current method of applying antibiotics kills all facial bacteria, whether they're harmful or beneficial. Knowing that one strain of P. acnes is actually beneficial would likely lead to more targeted treatment, including probiotics to encourage the growth of healthy bacteria. Conversely, bacteriophages could be used to kill off the harmful bacteria.Overall, it would mean instead of trying to destroy the community of bacteria living on your face, you'd manage it like a microbial zookeeper. That may sound odd, but it's part of a more subtle understanding of how microbes affect us. And carefully cultivating the bacteria on your face is a small price to pay for healthy skin, right?