Germs Mingle Most on Palms, Feet, Forearms

Nov. 6 -- THURSDAY, Nov. 5 (HealthDay News) -- A new "atlas" of bacterial life on and within the human body has uncovered the fact that your palms, feet and forearms are a veritable United Nations of germs.

The scientists, using sophisticated gene-sequencing technologies, pinpointed specific bacterial types and where they like to thrive on and within the body. They found a wide variability of bacteria, depending on the spot on the body. They also found that bacterial colonies differed person to person, with each individual carrying his or her own "personalized" assortment of microorganisms.

"We've always known that there are microbes on us and in us," said study author Noah Fierer, an assistant professor of microbial ecology at the University of Colorado at Boulder. "But we weren't always able to isolate them and differentiate them from each other. With these new techniques, we can."

"Each of us is really an archipelago of distinct habitats, at least as far as bacteria are concerned," added senior study author Robert Knight, an assistant professor of chemistry and biochemistry and computer science at the University of Colorado. "It's truly amazing how different the sites within the same body are, and how different the corresponding sites on different people are."

The team's work is being published Nov. 5 in the online version of Science. The study builds on earlier research, including a 2008 study that found that women had a greater diversity of bacteria on their palms than men.

The mapping project focused on seven to nine men and women, who were examined four times each over a three-month period. Researchers swabbed 27 different sites, searching for bacteria in virtually every nook and cranny, from hair to ear wax, mouth to nostril and trunk and legs.

So, where are the most popular places for bacteria to hang out? They seem to like the gut (no surprise there), forearms, palms, index fingers, the backs of the knees and soles of the feet, according to the study. At least that is where some of the most diverse and thriving colonies take root.