
Methods: Consecutive patients with early syphilis who received single-dose azithromycin under direct observation were prospectively observed between May 2012 and April 2013. T. pallidum was detected from clinical specimens using PCR assays and genotypic resistance to macrolides was determined. Information on adverse effects (AEs) were solicited 24 and 48 hours after treatment. Tests for rapid plasma reagen (RPR) titer were performed at baseline and every 3 months after treatment. Primary outcome of interest was decline of RPR titer by 4-fold or greater by 6 months after treatment.
Results: During the study period, a total of 126 HIV-infected patients (125 men who have sex with men) with a median RPR titer of 6 log2 (range, 2-10 log2) who received azithromycin were enrolled: 27 (21.4%) with primary, 35 (27.7%) secondary, and 64 (50.8%) early latent syphilis. 101 (80.2%) were receiving cART when syphilis was diagnosed, with a mean CD4 count of 565 cells/μl (range, 114-1376) and plasma HIV RNA load 1.3 log10 copies/ml (1.3-6.0 log10). One of the 54 T. pallidum strains identified (1.9%) harbored macrolide resistance mutations (A2058G). 122 and 126 were eligible for effectiveness and safety analysis, respectively. After 3 and 6 months of follow-up, the serologic response rate was 66.7% (48/72) and 85.7% (12/14), respectively. The serologic response rate by 6 months in 90 HIV-infected patients with early syphilis who received 1-dose BPG was 76.1% during the same study period. After taking azithromycin, 77.4% of the patients developed any gastrointestinal AEs, 29.8% central nervous system AEs, and 11.3% Jarisch-Herxheimer reaction. No significant association was observed between effectiveness by 3 months or AEs and use of cART.
Conclusion: While gastrointestinal AEs were common, single-dose azithromycin demonstrated comparable effectiveness to BPG in treatment of early syphilis among HIV-infected patients in an area of low prevalence of macrolide-resistant T. pallidum.

C. C. Hung,
None
P. Y. Wu, None
W. C. Liu, None
S. Y. Chang, None
H. Y. Sun, None
S. M. Hsieh, None
C. J. Yang, None
W. H. Sheng, None
B. R. Wu, None