Among the following, the narrow spectrum antibiotic is :
- amoxycillin
- chloramphenicol
- penicillin G
- ampicillin
Answer
(3) penicillin G
Solution
As per NCERT, antibiotics effective mainly against Gram-positive or Gram-negative bacteria are narrow spectrum antibiotics, while those killing or inhibiting a wide range of both are broad spectrum antibiotics.
Penicillin G has a narrow spectrum, so it is the answer. Ampicillin and amoxycillin are synthetic modifications of penicillin with a broad spectrum, and chloramphenicol is also a broad spectrum antibiotic.
Answer: (3)