A patient presents with a community-acquired uncomplicated urinary tract infection most likely due to E. coli. Which statement best describes the rationale for using sulfamethoxazole–trimethoprim (Bactrim) in this setting today?

Sulfamethoxazole–trimethoprim provides broad-spectrum activity against typical UTI pathogens and the combination is synergistic, often allowing lower doses and a practical treatment option when local resistance rates are acceptable.

Sulfamethoxazole–trimethoprim is preferred because it is a topical antifungal that also sterilizes the urinary tract and is therefore better than antibiotics targeting folate synthesis.

Sulfamethoxazole alone without trimethoprim is sufficient for empirical UTI therapy because the addition of trimethoprim would antagonize sulfonamide activity and reduce clinical efficacy.

Sulfamethoxazole–trimethoprim should never be used for UTIs because sulfonamides have no activity against gram-negative bacteria including E. coli.