Thanks to MCRO student Jack Iasiello for sending me a link to a fascinating video of how E. coli can quickly evolve antibiotic resistance. Harvard University and the Technion–Israel Institute of Technology set up a 2 foot by 4 foot “petri dish” of agar with increasing antibiotic gradients of either ciprofloxacin or trimethoprim. Then, set up a video and watched what happened… Link to article and video.
(Spoiler alert!! It took only 12 days to evolve resistance to even 1000x the normal dose that inhibited the initial strain). They also were able to track the specific strains that were evolving this resistance.