The effect of antimicrobials used for genital discharge disease on trichomonas vaginalis.

Abstract

Trichomoniasis is the most common sexually transmitted infection caused by the protozoan, Trichomonas vaginalis. T. vaginalis infection is often asymptomatic. This infection causes vaginal discharge in women and urethritis in men. It has been reported that trichomoniasis is associated with serious health complications and it increases the risk of HIV acquisition and transmission. The gold standard for trichomoniasis diagnosis is culture, however various point of care tests have been approved by the US FDA. Metronidazole is the standard treatment for trichomoniasis. Multiple cases of metronidazole-resistance have been reported since 1962. Syndromic management of STIs is used to treat multiple infections simultaneously based on the signs and symptom with which the patient presents. In South Africa, the vaginal discharge syndrome is managed with ceftriaxone, azithromycin and metronidazole. Ten T. vaginalis isolate were tested. Each isolate was tested against six combinations of two antimicrobials by the checkerboard method, four combinations of three antimicrobials and two combinations of four antimicrobials. The results obtained from the checkerboard of two antimicrobials were used to design the experiments for three and four antimicrobials combinations. The MICs for metronidazole ranged between 0.25 – 1 μg/ml and for doxycycline, they ranged between 64 – 128 μg/ml. Ceftriaxone and fluconazole showed no antitrichomonal activity. All combinations tested has an indifferent effect. Combinations of metronidazole and antimicrobials used in syndromic management including fluconazole has no effect against T. vaginalis. However, in the combination of metronidazole and doxycycline a decrease in the MICs for these antibiotics was observed. Further studies are required to test this combination on a larger sample size.