Everyone gives off their own personal cloud of bacteria, study reveals

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Just as humans possess DNA unique to every person, we also have a "microbial cloud" containing millions of bacteria that is almost as personal as a fingerprint, Yahoo! News reports. The revelation was made through a study led by James Meadow, a microbial ecologist at the University of Oregon.

NPR reports that according to Meadow, the little kid from Charles Schulz' Peanuts cartoon who walked around with a cloud of dirt exists, and "It turns out that that kid is all of us. It's just a microscopic cloud that's really hard to see."

The study was conducted by analyzing 11 volunteers, who were asked to sit alone in a chamber. The researchers then identified thousands of different types of bacteria in 312 samples of air and dust from the chamber. More interestingly, most of the participants were identified using the bacterial samples from the chambers they occupied.

"We expected that we would be able to detect the human microbiome in the air around a person, but we were surprised to find that we could identify most of the occupants just by sampling their microbial cloud," Meadow said. The researchers also claimed that this study may shed light on how humans spread bacteria, and help understand how infectious diseases are spread in buildings.

"A lot of the recent work on the human microbiome has revealed that we're kind of spilling our microbial companions all over our houses and our offices and the people around us," Meadow explained.

Additionally, by analyzing the DNA from bacteria in the air, the researchers could also detect plumes containing thousands of various kinds of bacteria. From each plume, they could also extract data such as a person's gender.

"We found that each person is unique in two respects," Meadow said. First, "we each give off different amounts of bacteria to the air around us," depending on how much as scratch and move around, and "we each give off a slightly different cocktail of those bacteria. There are just really subtle differences."

Wired also reports that according to Jack Gilbert, a microbiologist at Argonne National Laboratory, who worked on microbial clouds as well, "We know that every person has this unique microbiome profile and that they shed it into the environment," however, this study was the first to align the uniqueness of the microbial cloud to a genetic level.

This research may also be valuable to forensic investigations, as bacterial traces may be used to track people's whereabouts. A human being typically sheds a million microscopic particles through their breath, skin, clothes, and hair per hour, the researchers said, and all of these contain bacteria.

The scientists wrote, "Our data make clear that an occupied space is microbially distinct from an unoccupied one, and reveal for the first time that individuals occupying a space can emit their own distinct personal microbial cloud."