Antibiotic Coverage of Trimethoprim-Sulfamethoxazole

Antimicrobial Spectrum

• The Infectious Diseases Society of America recommends Trimethoprim-Sulfamethoxazole (TMP-SMX) as effective against Staphylococcus aureus, including many community-acquired methicillin-resistant S. aureus (CA-MRSA) strains, and active against β-hemolytic streptococci, though not considered first-line therapy 1, 2

Clinical Applications

• The American College of Emergency Physicians suggests TMP-SMX for outpatient treatment of purulent skin infections, particularly those caused by CA-MRSA, with a standard dosing of 1-2 DS tablets (160mg TMP/800mg SMX) twice daily 1, 2
• The World Journal of Emergency Surgery recommends a treatment duration of 7-14 days based on clinical response for skin and soft tissue infections 3

Important Considerations

• The World Journal of Emergency Surgery reports increasing resistance among MRSA strains, and suggests that when treating skin infections where both streptococci and MRSA coverage is needed, TMP-SMX may need to be combined with a β-lactam (e.g., amoxicillin) 3, 4
• The World Journal of Emergency Surgery advises against using TMP-SMX during the third trimester of pregnancy 3