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
Which of the following antimicrobial is effective against an organism producing extended spectrum beta lactamase? 
Select and explain. 
A. Amoxicillin-Clavulinic acid, B. Cefepime, C. Piperacillin-Tazobactam, D. Ceftriaxone
C: Piperacillin-Tazobactam
Answer: C: Piperacillin-Tazobactam 
Explanation: Ans. (C) Piperacillin-tazobactam(Ref: Harrison 18th/1247)Organisms producing ESBL-like Klebsiella are resistant to most beta-lactams except carbapenems.ESBL can be inhibited by beta lactamase inhibitors.Amoxicillin is not effective against Klebsiella whereas piperacillin has wide spectrum including Klesiella.