A 31-year-old cisgender woman from India who is visiting friends in the United States presents to a local sexual health clinic for evaluation of a red, painless ulcer on her vulva. In the clinic, she receives empiric treatment for syphilis and herpes simplex virus (HSV) infections. Ten days after the initial visit, she returns to the clinic with no improvement in the genital ulcer. All initial tests for syphilis and HSV are negative. She is referred to a dermatologist, and a biopsy of the genital ulcer is obtained. The pathology specimen shows Donovan bodies, a finding that strongly suggests a diagnosis of granuloma inguinale (donovanosis). Which one of the following is considered the recommended treatment regimen for granuloma inguinale? Azithromycin 1 gram orally once per week (or 500 mg daily) for at least 3 weeks and until all lesions have completely healed Erythromycin base 500 mg orally four times a day for 7 days Gentamicin 240 mg intramuscular once daily for 14 days Ceftriaxone 1 gram intramuscular in a single dose, with an optional second dose 1 week later if lesions have not completely healed by that time.