What is the drug of choice for a patient with Treponema pallidum infection requiring a single dose treatment?

Benzathine penicillin G is the drug of choice for treating Treponema pallidum infections, which is the causative agent of syphilis. This long-acting penicillin formulation provides effective and sustained levels of the antibiotic in the body following a single intramuscular injection.

The use of benzathine penicillin G is particularly advantageous in treating syphilis because it not only targets the organism effectively but also is well-tolerated with a low side effect profile. The single dose is sufficient for early-stage syphilis and provides the necessary therapeutic effect without requiring multiple administrations.

Other antibiotics such as ceftriaxone, aztreonam, and vancomycin are not first-line treatments for Treponema pallidum infections. While ceftriaxone may have some activity against certain strains of Treponema, it is not recommended specifically for syphilis treatment due to concerns about resistance and lack of guideline support. Aztreonam and vancomycin do not have efficacy against Treponema pallidum, as they target other types of bacteria. Therefore, benzathine penicillin G remains the preferred choice for its efficacy and dosing convenience.