If risk factors such as Pseudomonas or MRSA are present, which regimen is appropriate?

If risk factors such as Pseudomonas or MRSA are present, which regimen is appropriate?

• A. Piperacillin-tazobactam alone
• B. Meropenem or Imipenem plus Vancomycin
• C. Cefepime alone
• D. Aztreonam plus doxycycline

Answer: (B)

When there are risk factors for both Pseudomonas and MRSA, the goal is to cover both organisms from the start with empiric therapy. A carbapenem such as meropenem or imipenem provides strong activity against Pseudomonas and other Gram-negatives, but it does not reliably treat MRSA. Adding vancomycin supplies MRSA coverage, creating a regimen that addresses the two most concerning possibilities until cultures return. The other options fall short because they miss either MRSA or Pseudomonas coverage. Piperacillin-tazobactam or cefepime alone cover Pseudomonas but not MRSA. Aztreonam covers Gram-negatives (including Pseudomonas) but has no reliable activity against MRSA, and doxycycline is not a dependable MRSA agent in severe infections.

When there are risk factors for both Pseudomonas and MRSA, the goal is to cover both organisms from the start with empiric therapy. A carbapenem such as meropenem or imipenem provides strong activity against Pseudomonas and other Gram-negatives, but it does not reliably treat MRSA. Adding vancomycin supplies MRSA coverage, creating a regimen that addresses the two most concerning possibilities until cultures return.

The other options fall short because they miss either MRSA or Pseudomonas coverage. Piperacillin-tazobactam or cefepime alone cover Pseudomonas but not MRSA. Aztreonam covers Gram-negatives (including Pseudomonas) but has no reliable activity against MRSA, and doxycycline is not a dependable MRSA agent in severe infections.