Your body is surrounded by a personal bacterial cloud

Matt Davis

September 23, 2015

You are coated with microbes, no matter how often or well you shower. Our bodies are homes to trillions of bacteria that live inside of us and on us, forming a personal “microbial cloud”. These bacteria are found on your skin, your hair, your mouth, practically everywhere on you. “In a single centimeter of skin, you can find tens of thousands of bacteria,” says James Meadow, former University of Oregon researcher and co-author of a study published in the journal PeerJ.

The bacterial cloud that’s on you is formed when your body releases the microbes through different actions. “If I scratch my head, thousands of skin cells, cell fragments, bacteria, and fungi get airborne, when you pick your nose, burp your ABCs, or signal your compliments to the chef, gut microbes join the cloud. And, sorry if you were eating, but your farticles are also a medium for all the gut microbes living in you,” added Meadow. The microbial ecologist discovered that the bacterial cloud is unique for every person.

Meadow and his colleagues conducted an experiment in which they asked 11 volunteers to sit in a sanitized chamber with air filters that captured their bacterial clouds. After 4 hours the room’s filters were rich with thousands of bacteria. In another sterilized chamber there were no volunteers and the level of bacteria was much lower. The researchers extracted the DNA of the microbes from the rooms, sequenced the 16S gene (a genetic marker that distinguishes between bacterial types) and compared the bacterial colonies from the occupied room with the unoccupied one.

“Our results confirm that an occupied space is microbially distinct from an unoccupied one, and demonstrate for the first time that individuals release their own personalized microbial cloud,” said Meadow. Each person has a distinct cloud with its personal array of microbes like Streptococcus, Propionibacterium or Corynebacterium.

So what are the possible uses for this discovery? The researchers say it can help in identifying the ways germs spread, in a hospital, or during a contagious disease. Another possibility lies in forensics – to detect the past presence of a person in an indoor space, thanks to its personal bacterial cloud traces left there. Until then, get used to the fact that your body is a giant ecosystem for tiny critters science has just begun to explore.