In Vitro evaluation of susceptibility of Trichomonas vaginalisisolates to MetronidazoleI in Alborz province

Background and Aim : Trichomonas vaginalis is a common sexually transmitted protozoanparasite. Metronidazole, a ۵-nitroimidazole, is the drug of choice for treating T. vaginalis infection.Since some patients are resistant to metronidazole, thus, the present study aimed to explore thesusceptibility to metronidazole of isolates of T. vaginalis in aerobic and anaerobic conditions.Methods : Forty-five clinical T. vaginalis isolates from vaginal secretions and urine sediment werecollected from women and men referred to clinics, medical diagnostic laboratories, and hospitalsin Karaj. The isolates were purified by repeated cultures on TYM medium supplemented with ۱۰% calf serum, antibiotic (۱۰۰ μg/mL ceftriaxone and ۵۰ μg/mL ciprofloxacin), and fungicides (۲.۵μg/mL amphotericin B). ۱۰۵ live parasites were added to all ۲۴-wells tissue culture plates. Toevaluate the effect of metronidazole on Trichomonas vaginalis parasites, the concentrations of ۲,۴, ۸, ۱۶, and ۳۲ μg/ml were prepared and all groups were kept at ۳۷°C for ۲۴ and ۴۸ h. For MIC(minimum inhibitory concentration), the viabilities of the trophozoites in the wells under variousaerobic and anaerobic conditions were assessed by examining visually the motilities of the cellswith an inverted microscope after ۲۴ and ۴۸ h of incubation. For MLC (minimum lethalconcentration), the contents of each of the wells were inoculated into the bottoms of tubescontaining ۵ ml of fresh TYM medium, and the tubes were examined for the presence of motileafter five days.Results : The results of MIC and MLC of T. vaginalis isolates showed that all ۴۵ isolates had MICand MLC ≤۱۶ μg/ml. Since resistance to metronidazole was defined as MIC ≥۵۰ μg/ml, all isolateswere sensitive to metronidazole. Although there were no metronidazole-resistant cases, the lethaleffect of metronidazole on the parasites was more effective in anaerobic than aerobic conditions.In addition, the results showed that the death rate of parasites increases with the increase inincubation time.Conclusion : Although the results of this research have shown that no isolates resistant tometronidazole were found, they should be treated in a way that prevents the production of resistantstrains.

Keywords:

Trichomonas vaginalis , Metronidazole , In Vitro , MIC , MLC , Alborz