A cloud of germs floating around a person is almost as unique to them as a fingerprint, research has shown.
By studying samples of air floating around volunteers, scientists were able to identify which “microbial cloud” belonged to which individual.
Each cloud contains millions of bugs, composed of various combinations of microbes, which is an identifiable “signature” of a person following genetic analysis.
This means criminals might one day have to worry about leaving behind bacterial evidence at a crime scene, as well as just fingerprints, which can even be used to track their movements.
It’s unclear, however, whether it would be possible to spot them in a crowd.
Scientists put 11 volunteers in a chamber alone to test the air around them, finding thousands of bacteria types in 312 samples.
Within four hours, the individual occupants were matched to the cloud of bugs which floats around them.
Lead researcher Dr James Meadow, from the University of Oregon in the US, said: “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.”
As well as the implications for forensic investigations, the findings illustrate how humans shed bacteria into their surrounding environment.
Humans typically shed around a million microscopic particles from their breath, skin, clothes and hair per hour, many of which contain bacteria, said the researchers.
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.”
The study has been published in the online journal PeerJ.