Pharmacology · single question
Clindamycin is effective against all of the following EXCEPT one. Which is the EXCEPTION?
Show answer and explanation
Correct answer: D. Pseudomonas aeruginosa
- A. Clindamycin covers methicillin-sensitive Staphylococcus aureus (MSSA) and is used for skin/soft tissue infections.
- B. Clindamycin is effective against Streptococcus species including Streptococcus pyogenes and Streptococcus viridans — key pathogens in dental infections.
- C. Clindamycin is particularly useful for ANAEROBIC infections (periodontal abscesses, orofacial odontogenic infections) and is an alternative to amoxicillin for dental prophylaxis.
- D. CORRECT. Clindamycin has NO activity against Pseudomonas aeruginosa (a gram-negative, aerobic organism with intrinsic resistance to clindamycin). Clindamycin's spectrum covers gram-positive organisms and anaerobes — not aerobic gram-negative bacilli like Pseudomonas.