Question

Among the following, the narrow-spectrum antibiotic is-

• A. Penicillin G
• B. Ampicillin
• C. Amoxicillin
• D. Chloramphenicol

Answer 1

The correct option is A

Penicillin G

The correct option is A.

Explanation of correct option:

1. The narrow-spectrum antibiotics act against a particular group of bacteria.
2. Penicillin G is a narrow-spectrum antibiotic that specifically targets Gram-positive bacteria like pneumococci, streptococcus, and staphylococcus. They are unable to target Gram-negative bacteria.

Explanation of incorrect option:

Option B:

1. Ampicillin belongs to the group of synthetic beta-lactams.
2. It is broad-spectrum in its action and acts against both Gram-positive and negative bacteria.

Option C:

1. Amoxicillin is produced as an amoxicillin trihydrate and is effective against both Gram-positive and negative bacteria.
2. Thus it is a broad-spectrum antibiotic.

Option D:

1. Chloramphenicol is effective against various microbes like bacteria, rickettsiae, mycoplasmas, etc.
2. It is a broad-spectrum antibiotic.

Final answer: Penicillin G is a narrow-spectrum antibiotic.