Antibiotic resistance is when germs that cause illnesses, like bacteria, become stronger and more difficult to treat than usual. This happens when antibiotics (medicines used to fight and kill bacteria) are used too often or for the wrong reasons. This causes the bacteria to become resistant, meaning the antibiotic will not be able to kill it. The more antibiotics are used, the more these bacteria can become resistant, making them harder to treat. So it's really important to only take antibiotics when you really need them, and never share medicine with others.