Our body's immune system uses specially designed cells to locate and shut down microscopic invaders like bacteria, usually stopping them before they can cause trouble. Antibiotics are powerful bacteria-killing drugs that help our bodies regain the upper hand when a bacterial infection develops. Today, there are hundreds of antibiotics in use, most tailored to treat a specific kind of bacterial infection. Doctors have noticed that some bacteria are getting tougher to kill. Such bacteria are said to be resistant.
Bacterial resistance makes an infection much harder to treat.
Higher doses or stronger drugs may be required. In extreme cases, bacterial resistance can be fatal. The CDC says that up to half of the roughly 100 million prescriptions for antibiotics written each year are unnecessary. Although scientists agree bacterial resistance is a serious problem, there's less consensus on what to call it. If you don't finish a prescribed course of medication, you may be killing only those bacteria most susceptible to antibiotics.