Which antibiotic is appropriate for purulent cellulitis most likely caused by MRSA?

Which antibiotic is appropriate for purulent cellulitis most likely caused by MRSA?

• A. Trimethoprim/sulfamethoxazole
• B. Amoxicillin-clavulanate
• C. Cephalexin
• D. Nafcillin

Answer: (A)

Purulent cellulitis where MRSA is likely requires an antibiotic with activity against MRSA. Trimethoprim-sulfamethoxazole provides reliable MRSA coverage and is a common outpatient choice for suspected community-associated MRSA skin infections. The other options are beta-lactams that cover streptococci and methicillin-susceptible Staphylococcus aureus, but not MRSA reliably. Amoxicillin-clavulanate, cephalexin, and nafcillin therefore may fail if MRSA is the cause, making them less suitable when MRSA is likely.

Purulent cellulitis where MRSA is likely requires an antibiotic with activity against MRSA. Trimethoprim-sulfamethoxazole provides reliable MRSA coverage and is a common outpatient choice for suspected community-associated MRSA skin infections.

The other options are beta-lactams that cover streptococci and methicillin-susceptible Staphylococcus aureus, but not MRSA reliably. Amoxicillin-clavulanate, cephalexin, and nafcillin therefore may fail if MRSA is the cause, making them less suitable when MRSA is likely.