When can narrow-spectrum antibiotics be used to treat infectious diseases effectively?

• A. When the infection is unknown
• B. When the infection is known to be caused by a gram-positive bacterium
• C. When the infection is caused by multiple pathogens
• D. When broad-spectrum antibiotics are ineffective

Answer: (B)

Narrow-spectrum antibiotics are specifically designed to target particular types of bacteria, making them effective when the causative pathogen of an infection is known. In the context of this question, when an infection is confirmed to be caused by a gram-positive bacterium, a narrow-spectrum antibiotic that effectively targets gram-positive organisms can be chosen. This precision allows for effective treatment while minimizing the impact on the body’s normal flora and reducing the risk of developing antibiotic resistance that can occur with the use of broader-spectrum agents.

Using narrow-spectrum antibiotics when the specific pathogen is identified allows clinicians to provide an efficient and appropriate treatment tailored to the characteristics of the bacterium, leading to better patient outcomes and more responsible antibiotic stewardship.