Researchers successfully ID people from their microbial cloud

Research has explored the human microbiome for several years and it has been known that every person’s skin is teeming with millions of different microbes creating a living, breathing habitat layer unique to every individual.

However, new research is showing that the human microbiome actually extends beyond a person’s skin and into the air around them like a cloud or aura. Your cloud leaves bits of itself on the surfaces you touch and has led researchers to be able to use it to identify an individual.

For example, think of Pig-Pen, the dirty kid from Peanuts, a recent article explains. Turns out, the illustration of cloud of dirt around him at all times, may not be so far off.

“We give off a million biological particles from our body every hour as we move around. I have a beard; when I scratch it, I’m releasing a little plume into the air. It’s just this cloud of particles we’re always giving off, that happens to be nearly invisible,” James Meadow, a data scientist focuses on improving the health of the indoor microbiome in places like hospitals and homes, said in the article.

Recently, Meadow and his colleagues published a paper on their research that included sampling the air surrounding 11 different people in a sanitized experimental room and sequencing the microbes emanating from them. They determined that an occupied room is microbially distinct from an unoccupied one.

What’s more, the article states is that after three people spent four hours in a room together, giving off their microbes into the air and onto surfaces, Meadow’s team was able to distinguish each person based just on the bacteria in the surrounding air. “Each occupant’s personalized airborne signal can be statistically differentiated from other occupants,” they wrote.

“This was a first stab at it to see if it was possible. We didn’t expect to be able to tell people apart,” Meadow said in the article. “It kind of blew us away.” Among other differences between people’s microbial cloud “signatures,” one that stood out was their gender. The researchers were able to identify when a woman was in the chamber because the microbes in the air around her.

In a large part, it is your body heat that is responsible for generating your unique microbial cloud, the article explains. Heat rises off the body, propelling the particles outward. Your breath, which is part of your microbiome, is also hot and can push particles out too. The size of your cloud will have to do, in part, with how hot or cold your body temperature is at the moment.

How far the cloud reaches is all dependent on the “viscosity of the air,” according to Meadow. “We can only feel air when it’s hitting us. But for something that tiny [a microbe], air is more like water. If there’s any little bit of movement, they can just float around the room indefinitely. The tiniest bacteria can be picked up and stay in the air for hours,” he says. “Even just sitting at your desk, your cloud is probably reaching to your neighbor.”

Understanding the interplay between the microbial cloud and environment could form the basis for attempts to better engineer indoor spaces to prevent the transmission of diseases. “We could potentially design our buildings around that. If we know there’s an airborne disease risk, maybe we could develop ventilation accordingly,” Meadow said in the article. Places like hospitals or offices could stand to benefit, for example.

Meadow added that he believes our ability to distinguish between people based on their airborne microbial signatures will likely get better and better. “I can think of all kinds of reasons why we’d want to know if a nefarious character had been hanging around a room.” Plus, researchers already know that the skin microbiome differs according to where a person lives, so chances are good their microbial cloud does too. “It might be able to tell us where they’ve been.”

Still, there are many more unanswered questions. For example, researchers still don’t know whether taking antibiotics would totally rearrange a person’s microbial cloud, to the point of not being able to distinguish them.

While microbial cloud research is in its earliest stages, Meadow said in the article he is “100% convinced” that “this, along with the genome sequencing revolution, will give us better health.”

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