Your body is a city, a home to trillions of microbes. They live in your gut. They live on your skin. They interact, eat, reproduce and die on and inside you. In some cases, you need them just as much as they need you.
But your microbiome, the collective term for these hordes of microbial companions, doesn't stop at your fingertips. Your microbial city has microbial suburbs—a vast expanse of development stretching out from the urban core that is your body. And just as the sprawl of Atlanta takes on a different form from that of Berlin, or Tokyo or Phnom Penh, so too does your microbial suburbia differ from other people's.
Every time you move, says science writer Ed Yong, you transfer microbes into the environment—microbes that take up residence on their new turf. In as little as a day, says Anna Williams for New Scientist, you can seed a whole house with microbes that are characteristically “yours.”
In a study of the microbial diversity that exists in the homes of seven families researchers found that “[e]ach family had its own distinct microbial signature that could be used to identify them,” says Williams.
But more than just each house having its own microbial flora, the microbes in each was an extension of the inhabitants. Researchers showed this clearly, because the microbes followed people when they moved house, says Yong.
“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.”