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
Extended spectrum beta lactamases (ESBLs) are characterized by activity against all except. 
Select and explain. 
A. Penicillinases, B. Cephalosporinases, C. Oxyimino-cephalosporinases, D. Carbapenems
D: Carbapenems
Answer: D: Carbapenems 
Explanation: Ans. (D) Carbapenems(Ref: Katzung 10/e p739)Carbapenems like imipenem are the only beta lactams reliably efficacious against ESBL producing bacteria.