Which of the following antibiotic has a bacteriostatic effect on microbes?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Chloramphenicol
Antibiotics have either a cidal (killing) or a static (inhibitory) effect on microbes. Bacteriostatic antibiotics stop the growth of bacteria without killing them; erythromycin, tetracycline and chloramphenicol are examples. Penicillin, aminoglycosides and ofloxacin are bactericidal: they kill bacteria.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Antibiotics – “… Antibiotics have either cidal (killing) effect or a static (inhibitory) effect on microbes. A few examples of the two types of antibiotics are as follows: Bactericidal: Penicillin, Aminoglycosides, Ofloxacin. Bacteriostatic: Erythromycin, Tetracycline, Chloramphenicol.”