This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy: General Principles, Subject name: Pharmacology
Combination of amoxycillin with clavulanic acid is active against all of the following organisms except 
Select and explain. 
A. MRSA, B. Penicillinase producing Staph, aureus, C. Penicillinase producing N. gonorrhoea, D. Beta lactamase producing E. coli
A: MRSA
Answer: A: MRSA 
Explanation: Ans. (A) MRSA(Ref: GG 1479)Methicillin resistance occurs due to altered penicillin binding proteins, therefore cannot be reversed by b-lactamase inhibitor like clavulanic acid