How many doses of IM penicillin would you recommend for a patient with biopsy confirmed syphilis proctitis?

Syphilis is not a common cause of proctitis but apparently the biopsy confirms it. Almost certainly, the patient has primary or secondary syphilis, and standard treatment for early syphilis, a single 2.4 MU dose of benzathine penicillin G, is sufficient. If other evidence is more consistent with syp...