What's Crawling on Your Skin

The human body home to countless microorganisms of various species, and a new study of these diverse microbial communities finds each has its place. For example, forearm microbes don't grow as well on the forehead, but forehead microbes grew just fine on the forearm.

The scientists figured this out by studying 27 different body sites including the gut, mouth, ears, nose, and up to 18 skin surfaces on a handful of healthy adults on four separate occasions. And they moved microbes from one location to another and between participants.

Previous research has found that the microbial community in your stomach is as diverse as any found in Earth's seas or soils, numbering up to 100 trillion individuals and representing more than 1,000 different species.

The new study found that body site, not individual personal differences, has the greatest influence on the composition of microbial communities dwelling at specific skin sites, confirming similar previous work.

Some skin locations, like the index finger or back of the knee, often harbored more diverse microbes than the gut or mouth, the researchers report in the journal Science.

As far out the outside of the body, where do microbes like it best? As Healthday put one aspect of the findings: "Palms, feet and forearms are a veritable United Nations of germs."

Yeah, wash your hands, and then some.