Final answer:
Narrow-spectrum antibiotics are effective against a limited range of bacteria and target specific subsets of bacterial pathogens. An example is isoniazid, which treats infections caused by mycobacteria.
Step-by-step explanation:
The term for antibiotics that are effective against a limited range of bacteria is narrow-spectrum. These antibiotics target specific subsets of bacterial pathogens, such as gram-positive bacteria or limited numbers of gram-negative bacteria. An example of a narrow-spectrum antibiotic is isoniazid, which is used to treat infections caused by mycobacteria.