A cloud of microbes surrounds a person

Everyone’s storing data in the cloud these days — including, apparently, people’s microbes.

The bacteria that live in and on a human body form a personal microbial cloud around a person. This microscopic mist spreads through the air and settles on nearby surfaces. This cloud can be used to identify not only the presence of a person, but sometimes also the person’s identity, researchers report September 22 in PeerJ.

After three volunteers sat in a sanitized room for four hours (along with a sterilized laptop for entertainment), the researchers found that human-associated bacteria had gathered on collection dishes in the room. These bacteria included species like Staphylococcus epidermidis, often found on human skin, and Streptococcus oralis, a common mouth resident. Each person’s cloud contained distinct types and amounts of bacteria — so distinct, in fact, that each subject could be identified by their microbes.

In a subsequent experiment, five of eight participants could be identified by airborne bacteria in air filters in the room. Two of the five people produced so much microbial material that they could be identified based on cloud bacteria that got stuck in the room’s air ventilation ducts.