These kids' microbial fingerprints are all over that floor. Shutterstock.com

Each of us has a unique bacterial fingerprint. New research indicates it's stamped all over our homes.

It seems every day I see a new headline about gut bacteria—those teems of microbes that colonize our stomachs, regulating our eating habits and bolstering our immune systems

Perhaps less attended to is the fact that microbes inhabit not just our bellies, but our entire bodies. In fact, each one of us has a "microbial fingerprint," a unique signature of bacteria that we stamp, in the millions, on virtually every surface we touch. 

It would follow, then, that the environments we most regularly interact with would strongly bear our microbial fingerprints, not to mention the fingerprints of those we're often with.

That fact—and how it might play into our health—is what prompted The Home Microbiome Project, an close-up analysis of how microbes and humans interact inside houses and apartments. Conducted by researchers at the U.S. Department of Energy and the University of Chicago, results of the study were published today in Science.

"We know that certain bacteria can make it easier for mice to put on weight, for example, and that others influence brain development in young mice," microbiologist Jack Gilbert, who led the study, has said. "We want to know where these bacteria come from, and as people spend more and more time indoors, we wanted to map out the microbes that live in our homes and the likelihood that they will settle on us."

Over the course of six weeks, seven families, which included 18 people, three dogs and one cat, swabbed their hands, feet and noses daily for samples of their microbial colonies. They also collected swabs from household surfaces, like doorknobs, light switches, floors and counter-tops.

DNA analysis of each sample revealed that the participants substantially affected the microbial communities in a house, and among household occupants. Couples shared lots of microbes, and so did parents, children, and even pets. Ditto for people and their surroundings. In fact, the researchers found that after three of the families moved, the new houses were microbially identical to the old houses in less than a day. ​And soon the old space had a new bacterial stamp, too. 

"You could theoretically predict whether a person has lived in this location, and how recently, with very good accuracy," Gilbert said.

And perhaps more usefully, determining our microbial interactions in our indoor environments could help make for healthier homes. At one point, the researchers detected a potentially disease-carrying bacteria first on one person's hands, then on a kitchen counter, and then on another person's hands. If further research revealed a pattern in this kind of transmission, then homeowners could pinpoint risky bacterial hot-spots. 

Top image: pio3/Shutterstock.com

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