Every Pore on Your Face Is a Walled Garden

A close examination of human skin found that each pore had a single variety of bacteria living inside.

Your skin is home to a thousand kinds of bacteria, and the ways they contribute to healthy skin are still largely mysterious. This mystery may be getting even more complex: In a paper published Thursday in the journal Cell Host & Microbe, researchers studying the many varieties of Cutibacterium acnes bacteria on 16 human volunteers found that each pore was a world unto itself. Every pore contained just a single type of C. acnes.

C. acnes is naturally occurring, and the most abundant bacteria on skin. Its link to acne, the skin disease, is not clear, said Tami Lieberman, a professor at M.I.T. and an author of the new paper. If biologists want to unpack the relationship between your face’s inhabitants and its health, it will be an important step to understand whether varying strains of C. acnes have their own talents or niches, and how the strains are distributed across your skin.

To collect their samples, Dr. Lieberman and her colleagues used commercially available nose strips and old-fashioned squeezing with a tool called a comedone extractor. They then smeared samples, each a bit like a microscopic glacial core, from within pores on Petri dishes. They did the same with samples from toothpicks rubbed across the surface of participants’ foreheads, cheeks and backs, which picked up bacteria living on the skin’s surface rather than in the pores. They allowed the bacteria to grow, then sequenced their DNA to identify them.