Which combination best describes empiric therapy for HAP/VAP to cover both MRSA and Pseudomonas?

• A. Vancomycin alone
• B. Vancomycin or linezolid, plus anti-pseudomonal agent
• C. Doxycycline alone
• D. Piperacillin-tazobactam alone

Answer: (B)

In hospital-acquired or ventilator-associated pneumonia, starting treatment that covers both MRSA and Pseudomonas is essential because these pathogens are common and can drive severe illness. The best approach is to pair an agent active against MRSA (such as vancomycin or linezolid) with an anti-pseudomonal drug (for example, piperacillin-tazobactam or another anti-pseudomonal beta-lactam). This ensures broad initial coverage while cultures and susceptibilities are pending, allowing therapy to be narrowed later if MRSA or Pseudomonas is not present or is susceptible.

Vancomycin alone would miss Pseudomonas; doxycycline alone is not reliably effective for HAP/VAP and does not provide robust Pseudomonas coverage; piperacillin-tazobactam alone covers Pseudomonas but not MRSA. The dual approach addresses both major threats upfront, which is why it’s chosen for empiric therapy in this setting.