This video from the Science Channel illustrates the power of microbes. Bacteria might be small, but they carry a genome that codes for proteins, just like us, and their genomes are often capable of rapid change.
Researchers have actually shown that when bacteria are exposed to an antimicrobial drug, they can gradually gain an ability to evade that antibiotic and grow anyway. Learn more about how scientists designed this experiment, and see the results. It’s a demonstration of why antibiotics should only be used as directed, and until the prescription has been finished. Casual use of antibiotics can help microbes gain resistance to them.