Your Arm: Grand Central for Germs

Using DNA taken from germs on the arms of six healthy people, researchers discovered that their skin was crawling with "a virtual zoo of bacteria" -- 182 species in total.

In the new study, the researchers took swabs from the inner right and left forearms of six individuals picking the region halfway between the wrist and the elbow for its convenience. "It's not where they wash their hands," explains [a researcher]. "And they don't have to undress." The researchers wanted to be able to compare two similar parts of the body. Because they also wanted to study change over time, they took swabs from four of the individuals 8 to 10 months after the first test.

Roughly half, or 54.4%, of the bacteria identified in the samples represented the genera Propionibacteria, Corynebacteria, Staphylococcus and Streptococcus, which have long been considered more or less permanent residents in human skin…

In each individual, the bacterial populations varied over time while revealing a core set of bacteria for each individual… "What that suggests," [a researcher said], "is that there is a scaffold of bacteria present in everybody's skin. Some stay and others come and go."

Eight percent of the germs found had never been discovered before.

Here's a question for you scientist readers: Do all these germs come from the environment? If you were raised in an isolated environment (like the famous Bubble Boy) would you not have any of these bacteria on your arm?
Human Skin Harbors Completely Unknown Bacteria [press release]