All of the following are true regarding penicillins EXCEPT

• A. Most penicillins only cross the blood brain barrier when the meninges are inflamed.
• B. Penicillins don t require dosage adjustment in renal failure
• C. Penicillins inhibit cross linkage of peptidoglycans in the cell wall
• D. Piperacillin is a penicillin active against pseudomonas
• E. Only about 5 to 10% of people with a past history of penicillin allergy have a reaction on re exposure