While most people have been taught to fear and loathe bacteria and other microscopic organisms (just watch some soap commercials), healthy people actually carry around more bacterial cells with them than their own human cells. It's estimated that there are ten times as many bacterial cells on a typical person than the number of cells that carry a person's own genetic code. About 100 trillion microscopic life forms usually live peacefully on (or in) our bodies, but the microbes that cause disease make us suspicious of all of them. In our battle to defeat the bad guys, though, we should be careful to limit the collateral damage. Here are just a few projects working on fighting "bad" bacteria without killing them all.
If you'd like to read more awesome and interesting stuff, check out this unrelated (but not entirely random!) Techdirt post