PREVENTION OF EXPERIMENTAL HAEMOPHILUS-DUCREYI INFECTION - A RANDOMIZED, CONTROLLED CLINICAL-TRIAL

Human subjects were infected with Haemophilus ducreyi All subjects dev eloped papules and were randomized to treatment with a single dose of azithromycin (1g) or ciprofloxacin (500 mg). At weekly intervals, volu nteers were reinoculated with H. ducreyi, and drug concentrations were measured in peripheral blood mononuclear cells (PBMC). When papules d eveloped, the subjects were treated with antibiotics and dismissed fro m the study. Eight of the ciprofloxacin-treated subjects developed pap ules 1 week after the initial treatment, and the ninth subject develop ed disease 2 weeks after treatment. The 9 azithromycin-treated subject s developed papules 4-10 weeks (mean, 6.8) after the initial treatment (P < .001). Azithromycin was detected in PBMC for 3-6 weeks (mean, 4) . Pre-and posttreatment lesions had histology typical of experimental chancroid or were culture positive. Azithromycin prevents experimental chancroid for nearly 2 months. These findings have implications for s trategies to prevent chancroid.