Like the Peanuts character, Pigpen, each of us emits a cloud of bacteria that is uniquely our own, according to a new study.
This "personal microbial cloud" is so distinctive that researchers can even identify someone just by studying the air in that individual's room.
"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," lead author James F. Meadow, a postdoctoral researcher formerly from the Biology and the Built Environment Center at the University of Oregon, said in a press release.
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Meadow and his team asked 11 volunteers to sit, one by one, in a sanitized experimental chamber. The scientists next sequenced the microbes in the air of the chamber after each person left.
This work in itself was a monumental task, as the researchers looked at more than 14 million sequences representing thousands of different types of bacteria found in the 312 samples from air and dust obtained in the experimental chamber.
The scientists found that most of the occupants, after sitting alone in the chamber for about 4 hours, could be identified just by the unique combinations of bacteria that they left behind in the surrounding air.
The study focused on categorizing whole microbial communities rather than identifying pathogens. Meadow and his colleagues did, however, find a lot of Streptococcus, which is commonly found in the mouth.
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They also identified Propionibacterium and Corynebacterium, which are both common skin residents. In fact, all of the test subjects emitted these three widespread types of microbes.
Different combinations of bacteria, however, were identified for nearly all of the study participants.
"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," the authors concluded.
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In the future, the research could help to explain how infectious diseases spread from person to person in buildings. The findings might also revolutionize CSI work, since a criminal could be long gone from a structure, but his or her telltale personal microbial cloud could remain.
The study appears in the latest issue of the journal PeerJ.