Scientists at Harvard University setup the MEGA-plate, essentially a giant petri dish, with varying levels of antibiotic. Then they let the bacteria have a go, and you can see the bacteria actually evolve. Ed Yong for the Atlantic:
What you’re seeing in the movie is a vivid depiction of a very real problem. Disease-causing bacteria and other microbes are increasingly evolving to resist our drugs; by 2050, these impervious infections could potentially kill ten million people a year. The problem of drug-resistant infections is terrifying but also abstract; by their nature, microbes are invisible to the naked eye, and the process by which they defy our drugs is even harder to visualise.
Until you watch the video, that is.