Macrolide Resistance in Treponema pallidum in the United States and Ireland

An HIV-infected patient in San Francisco with primary syphilis was treated with azithromycin, but the lesion did not resolve. The authors of this case report confirmed resistance to azithromycin and identified a mutation in the 23S rRNA genes of T. pallidum . The mutation was also found in samples collected in Baltimore, Seattle, and Dublin. The researchers confirmed resistance to azithromycin and identified a mutation in T. pallidum . For decades, syphilis infection has been treated with penicillin, and Treponema pallidum has not developed resistance to penicillin. In many countries, the recommended treatment for early syphilis is a single dose of penicillin G benzathine, which maintains bactericidal levels for weeks, killing the slowly metabolizing treponemes. Azithromycin, which has a long tissue half-life and can be administered orally, was found to be effective in the treatment of syphilis in a rabbit model 1 and in small studies in humans. 2 – 6 Because of its convenience and efficacy, azithromycin is increasingly being used for the treatment of syphilis by clinicians and in disease-control . . .