Do We Need To Worry About Being Attacked By Other Peoples' Belly Button Bacteria?

Jiri Hulcr, a postdoctoral student at the Belly Button Biodiversity Project at North Carolina State University, says yes.

One of the main goals, really, one of the long-term overarching goals of this project is to change people’s perception of their own symbiotic microflora. Only if something goes wrong, only if one member predominates, or if we scrub ourselves too much - for example, if we do something that’s akin to clear-cutting in the forest, then you get all the weeds growing really fast.

[I]f the forest is old and dominated by diversity of slow-growing and metabolically versatile trees, or in our case bacteria, then you generally tend to get balance. And of course there are weeds growing all over the place, but they’re never dominant. And it’s only when we do something wrong or when there is something wrong with our immune system or if there is something wrong with our bacterial ecosystem that we see some of those go wild and grow over everybody else.