Examples of narrow spectrum antibiotics include macrolides, bacitracin, polymyxins, vancomycin and nitroimidazoles. Narrow spectrum antibiotics only work against a select group of bacteria or single specific microorganism.
The advantage of narrow spectrum antibiotics is that they treat specific conditions without causing an antibiotic resistance in other conditions. For example, overuse of a broad spectrum antibiotic like penicillin can cause bacterial resistance in a number of infections that are not intentionally being treated. Using a narrow spectrum antibiotic also limits killing healthy microorganisms in the body.
The challenge of using narrow spectrum antibiotics to treat illness is that doing so requires an exact diagnosis. This can be time consuming and harmful when dealing with a fast moving bacterial infection.