Our Microbes, Ourselves

Ed Yong reviews the first results from the Home Microbiome Project, which seeks to “map” the ecologies of microbes we carry with us wherever we go. What researchers learned after analyzing six weeks’ worth of participants’ swabs from around their homes:

[I]t rapidly became clear that each home has a distinctive microbiome, which comes largely from the people who live in it. Light switches and doorknobs look like hands. Floor looks like feet. Kitchen countertops look like skin. We turn our homes into microbial reflections of ourselves.

This happens quickly. As soon as we move into a space, we inject microbes into it, and those bugs colonise the area within 24 hours. One of the young couples demonstrated this in the starkest way:

at the start of the study, they were staying in a hotel. After they moved, their new home was microbially indistinguishable from the hotel room. “People always say, “Ewwwww, someone else was in this room and it has their microbes all over it.” That’s irrelevant,” says [researcher Jack] Gilbert. You are constantly overwriting the microbes in the world around you with your own. When you move house, your microbial aura moves too.

Yong shares why Gilbert decided to welcome a new addition to his family – a shelter dog named Captain Bo Diggley – after seeing the study’s results:

Dogs supercharge the flow of microbes between people and their homes. If two people share a house, they also tend to share their microbes, and couples do so more than mere roommates. But if there’s a dog around, that traffic surges. Dogs also increase the microbial diversity of a home by bringing in bacteria from the outside world. In a world where the presence of bacteria is equated to filth and squalor, some people might see that as a bad thing. Gilbert saw it as a plus. We need microbes to help train our immune systems and to ensure that they develop properly. “We wanted to make sure that our kids had that capacity,” he says.