In vitro activity of nitazoxanide against some metronidazole-resistant and susceptible Trichomonas vaginalis isolates

Abstract Trichomonas vaginalis cases refractory to metronidazole (MTZ) treatment had been reported. This study aimed to the assessment of in vitro metronidazole resistance among Trichomonas positive cases with treatment failure by determination of metronidazole minimal lethal concentration (MLC), and to the evaluation of the in vitro efficacy of nitazoxanide (NTZ) as compared to metronidazole (MTZ) in both resistant and susceptible isolates. Drug testing was carried out by an aerobic tube assay where suspension of Trichomonas trophozoites was exposed for 24 and 48 h to serial dilution of metronidazole and nitazoxanide. In refractory isolates n = 30, median MLC conc. for MTZ was 100 μg/ml versus 50 μg/ml for NTZ (P