The public health burden of Treponema pallidum subspecies pallidum, the etiologic agent of syphilis, is substantial. Left untreated, syphilis can often span decades with multiple stages of infection and can cause serious complications [1]. Early syphilis can also increase the chances of acquiring and transmitting human immunodeficiency virus (HIV) infection by 2- to 5-fold [2, 3]. Syphilis rates have been increasing both in the United States and internationally, with incidence higher among men who have sex with men (MSM) and people living with HIV infection [4, 5].

The currently recommended treatment for syphilis by both the World Health Organization and the Centers for Disease Control and Prevention is injectable benzathine penicillin G (BPG) [6]. More importantly, BPG is the only recommended treatment for syphilis in pregnancy. Doxycycline, tetracycline, and ceftriaxone are recommended alternative treatments [5, 6]. However, there are limitations to their use; tetracyclines cannot be administered during pregnancy or to children, while treatment with ceftriaxone requires multiple daily intramuscular injections or intravenous administration, making treatment adherence potentially challenging. There is a need to identify safe, effective, and convenient antibiotics to treat early syphilis.

Reference link-