What Is Antibiotic Overuse?
Antibiotic overuse is when antibiotics are used when they're not needed. Antibiotics are one of the great advances in medicine. But overprescribing them has led to resistant bacteria (bacteria that are harder to treat).
Some germs that were once very responsive to antibiotics have become more and more resistant. This can cause more serious infections, such as pneumococcal infections (pneumonia, ear infections, sinus infections, and meningitis), skin infections, and tuberculosis.
What Do Antibiotics Treat?
Two major types of germs can make people sick: bacteria and viruses. They can cause diseases with similar symptoms, but they multiply and spread illness differently:

• Bacteria are living organisms existing as single cells. Bacteria are everywhere and most don't cause any harm, and in some cases are beneficial. But some bacteria are harmful and cause illness by invading the body, multiplying, and interfering with normal body processes.
  
  Antibiotics work against bacteria because they kill these living organisms by stopping their growth and reproduction.
• Viruses, on the other hand, are not alive. Viruses grow and reproduce only after they've invaded other living cells. The body's immune system can fight off some viruses before they cause illness, but others (like colds) must simply run their course. Antibiotics do not work against viruses.

Why Are Antibiotics Overprescribed?
Doctors prescribe antibiotics for different reasons. Sometimes they prescribe them when they're not sure if an illness is caused by bacteria or a virus or are waiting for test results. So, some patients might expect a prescription for an antibitoic and even ask their doctor for it.
For example, strep throat is a bacterial infection, but most sore throats are due to viruses, allergies, or other things that antibiotics cannot treat. But many people with a sore throat will go to a health care provider expecting — and getting — a prescription for antibiotics that they do not need.