Inclusion Criteria:  Diagnosed cases of primary, secondary, or early latent syphilis with RPR titer ≥1:8 within 3 weeks prior to enrollment 18 years of age or older Able to provide informed consent Individuals with HIV infection must be on treatment for HIV infection and virologically suppressed (viral load <200 copies/mL) or have a CD4 count ≥ 350 cells/mm3 according to most recent labs before study enrollment  Exclusion Criteria:  Pregnancy or a positive pregnancy test on the day of enrollment Patients showing signs and symptoms of neurosyphilis Serofast RPR titer, defined as persistently positive RPR titer without more than 4-fold (2-titer level) change for 12 months or greater Recent (within the past 7 days) or concomitant antimicrobial therapy with activity against syphilis, namely azithromycin, doxycycline, ceftriaxone, or other beta-lactam antibiotics (e.g. amoxicillin) Individuals with HIV infection who report HIV treatment interruption for more than 4 weeks since their most recent viral load or CD4 test Self-reported allergy to cephalosporins or penicillin Unwilling or unable to attend follow-up visits