Couples who live together know that there’s bound to be some sharing, whether it’s sitting down for a meal together or accidentally using a partner’s favorite coffee mug. Some couples even share a similarity in facial features. Now it turns out that all the time spent together means you share microbial skin communities, according to a new study—that’s right, the two of you have been colonized by the same germs.
According to research from microbial ecologists at the University of Waterloo, in Canada, people who live together have a major influence on each other’s microbial skin communities. In fact, the shared skin commonalities are so strong that computer measurements could identify which couples were cohabiting with 86 percent accuracy, reports mSystems, an open-access journal of the American Society for Microbiology.
For their research, the team of Ashley Ross, Josh Neufield and Andrew Doxey, looked at 330 skin swabs taken from 17 different sites of heterosexual participants living in the Waterloo area. Participants were required to collect their own samples, taking swabs from sites including their upper eyelids, outer nostrils, inner nostrils, armpits, torso, back, navel, and palms of hands.
After collecting the samples, researchers were able to link couples back together. The most similarities among couples’ microbial skin communities were found on the feet, which according to researchers makes sense, as couples often walk barefoot on the same floor spaces. (By the way, these are the germiest spots in your home.)
“This process likely serves as a form of microbial exchange with your partner, and also with your home itself,” Neufield told Eureka Alert. “As a result, partners end up with the same mix.”
Additional testing sites that showed strong similarities in microbial communities include the area of the inner thigh, which showed more in common among people of the same biological sex than among their partners. Computer measurements were able to discern between men and women with perfect accuracy by looking at these inner thigh samples.
Researchers point out though that despite the shared similarities among couples, “cohabitation is likely less influential on a person’s microbial profile than other factors like biological sex and what part of the body is being studied.” They note that your own microbial profile is more likely to resemble yourself than that of your partner. They hope that future research can explore and understand this occurrence in humans, as well as other mammals.
“Ultimately what we’re trying to learn is whether skin microorganisms have co-evolved with their hosts over time,” Neufield told Eureka Alert.