We are definitely never alone.
"University of Colorado biochemistry assistant professor Rob Knight [and] lead researcher Noah Fierer ... took samples from the palms of 51 college students — that's 102 hands — and tested the samples using a new, highly detailed system for detecting bacteria DNA.
They identified 4,742 species of bacteria overall, only 5 of which were on every hand, they report on Monday's online edition of Proceedings of the National Academy of Sciences.
The average hand harbored 150 species of bacteria.
Not only did individuals have few types of bacteria in common, the left and right hands of the same individual shared only about 17 percent of the same bacteria types, the researchers found."
Women have substantially more bacteria on their hands than men, for reasons that are unclear. Men's hands are more acid? Women use moisturizers which harbor bacteria? Women don't wash their hands as well? Just guesses at this point.