Antimicrobials USMLE Step 1 Practice Question
A 66-year-old man with methicillin-resistant Staphylococcus aureus bacteremia (blood cultures positive for MRSA) receives intravenous vancomycin infusion. Within 10 minutes, he develops flushing, pruritus, and erythema of the face, neck, and upper torso. Vital signs: BP 148/92 mmHg, HR 112 bpm, RR 20/min, Temp 37.2°C, SpO2 98% on room air. He denies dyspnea or angioedema. Which antimicrobial is the most likely cause of this reaction?
Answer choices
- AAztreonam
- BVancomycinCorrect answer
- CDaptomycin
- DNafcillin
- ELinezolid
- FRifampin
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations â plus adaptive practice that targets your weak areas â with a free MedBoardPRO account.