Final answer:
Antibiotics are drugs used to fight infections and have been abused due to overuse and misuse, leading to antibiotic resistance.
Step-by-step explanation:
The drug that is used to fight infection and has been abused is antibiotics. Antibiotics are medications that are specifically designed to kill or inhibit the growth of bacteria. However, overuse and misuse of antibiotics have led to the development of antibiotic resistance, where bacteria evolve and become resistant to the effects of the drugs. This makes the antibiotics less effective in treating infections.