WASHINGTON — Sorry, clean freaks. No matter how well you scrub your home, it's covered in bacteria from your own body. And if you pack up and move, new research shows, you'll rapidly transfer your unique microbial fingerprint to the doorknobs, countertops and floors in your new house, too.
In fact, researchers who studied seven families in Illinois, Washington and California could easily match up who lived where using their microscopic roommates.
It's all part of an effort to understand how the trillions of mostly beneficial bacteria that live in and on our bodies — what's called the human microbiome — interact with bugs in the environment to affect our health.
"We have so little information about where the microbes come from that shape our microbiome, whether it's for health or disease," said microbiologist Jack Gilbert of the Argonne National Laboratory and the University of Chicago.
Where do people spend most of their time? "It's the indoor environment. The best place to look at that was the home," said Gilbert, who led the Home Microbiome Project.
Gilbert recruited seven households that included 15 adults, three children, three dogs and a cat. For six weeks, participants collected samples of the microscopic bugs living on and around them by swabbing the hands, feet, noses and paws of everyone in the household, plus doorknobs, light switches, floors and countertops.
Back in the laboratory, Gilbert's team identified the bugs by their DNA, and they reported Thursday in the journal Science that people substantially affect the microbial communities in their homes.
Different homes harbored markedly different bacterial populations, but closely matched the microbiomes of their residents.
The big surprise: How quickly the bugs settled in. Like Pigpen's trailing cloud of dust in the Peanuts comic strip, when three families moved, it took about a day for the microbes in their new homes to closely resemble those in the old ones.