Antibiotics are drugs used to treat bacterial infections. These drugs have been responsible for saving millions of lives over the years. Partially because they are so useful, doctors have tended to overuse them, and this has allowed bacteria to adjust to their presence, becoming resistant to their bacteria-killing effects. As a result of the development of antibiotic resistance, certain types of bacteria have become extremely difficult to treat since few (or no) antibiotics remain effective against them. For this reason, it has become critically important to develop new drugs that can treat these difficult infections.