Which antimicrobial therapy is best for a skin infection caused by community-acquired MRSA?

Trimethoprim-sulfamethoxazole is an effective choice for treating skin infections caused by community-acquired MRSA (methicillin-resistant Staphylococcus aureus) for several reasons. This combination antibiotic works by inhibiting bacterial folic acid synthesis, which is essential for bacterial growth and replication.

Community-acquired MRSA strains are often resistant to beta-lactam antibiotics, such as dicloxacillin and amoxicillin-clavulanate, making those options less effective. Dicloxacillin, while suitable for methicillin-sensitive Staphylococcus aureus (MSSA), does not cover MRSA and is therefore ineffective in this case. Cefadroxil, a first-generation cephalosporin, similarly lacks coverage for MRSA, consequently rendering it inappropriate for treating MRSA infections.

In contrast, trimethoprim-sulfamethoxazole has been shown to demonstrate good efficacy against many strains of MRSA, particularly those encountered in community settings. Its oral bioavailability makes it convenient for outpatient treatment of skin and soft tissue infections caused by these resistant bacteria. Therefore, when considering appropriate therapy for a skin infection suspected or confirmed to be due to community-acquired MRSA, trimethoprim-sulfamethox