Antibiotics were invented to prevent serious infections and deaths. But in the U.S., about 2 million people become infected with bacteria that can’t be treated by antibiotics. At least 23,000 people die from those infections every year.
Bacteria have mutated and become resistant to many antibiotics. That's happened because many of these medications were over prescribed, given in too high of doses or used for the wrong reasons, such as when someone has a virus not a bacterial infection. Antibiotics have also been overused in farming.
What's the solution? At this point, many doctors are being much more conscientious about prescribing antibiotics only when completely necessary. Some hospitals even have registries logging when antibiotics are administered.