This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
Antimicrobials effective against anaerobic bacteria include the following EXCEPT: 
Select and explain. 
A. Tobramycin, B. Clindamycin, C. Chloramphenicol, D. Metronidazole
A: Tobramycin
Answer: A: Tobramycin 
Explanation: (Ref: KDT 6/e p719, 720) Aminoglycosides require oxygen for transpo in the bacterial cell. These are therefore ineffective against anaerobic organisms.