Microbiome Monday: Skin Deep

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It's Microbiome Monday again! The Museum’s special exhibition The Secret World Inside You opened this weekend, and we're bringing you weekly primers on the human microbiome and the research surrounding it from Curators Rob DeSalle and Susan Perkins, as well as from other scientists who are working in this exciting field.

While much research focuses on the microbes that live inside us, those that live on us are important as well. Your skin is patchwork of ecosystems—some moist and humid, others hot and dry—that is as diverse as any continent.

Skin Epi Layer

Your skin hosts a wide variety of microbes in huge numbers, but populations can vary among individuals.

© AMNH/B. Peterson


Perhaps not surprisingly, skin, our interface with the world, supports the body’s most diverse population of bacteria. There are at least 1,000 different species found on skin, along with dozens of fungi and other microbes. Most of these bacteria aren’t harmful, and many in fact serve protective functions. These species live among the dead skin cells that make up the outer layer of our skin, defending us from disease while they guard their own turf against other microbes.

One example of this relationship is a strain of the bacterium Bacillus subtilis, which is sometimes found on the skin, which produces bacitracin—a common ingredient in many over-the-counter antibiotic ointments. B. subtilis also releases toxic chemicals to kill fungus, possibly including Trichophyton interdigitale and other species that cause athlete’s foot.

To learn more about your microbiome, visit The Secret World Inside You, open now at the Museum. 

A version of this story originally appeared in the Fall issue of the Member magazine Rotunda.