A 36 years old woman recently treated for leukemia is admitted to the hospital with malaise, chills and high fever. Gram stain of blood reveals the presence of gram negative bacilli. The initial diagnosis is bacteremia and parenteral antibiotics are indicated. The record of the patient reveals that she had severe uicarial rash, hypotension and respiratory difficulty after oral pencillin V about 6 months ago. The most appropriate drug should be:
High-Yield Explanation
In patient with severe sensitivity to penicillin, all beta lactams except monobactams are contraindicated. Both Aztreonam and imipenem are effective for gram negative infections but as the patient is allergic to beta lactams (carbapenems show cross allergy), Aztreonam is preferred in such a patient.