Inhibition of Trichomonas vaginalis by fungi during associative growth

In controlled studies of associative growth, Candida albicans and Torulopsis glabrata, but not Candida parapsilosis, inhibited the proliferation and eventually the viability of Trichomonas vaginalis. The inhibition patterns produced against the trichomonad by C. albicans or T. glabrata were observed with trichomonad-fungus inoculum ratios ranging from 230:1 to 1:100. The onset of inhibition of T. vaginalis by T. glabrata was immediate, whereas that of C. albicans began after incubation for 48 hr. Under routine clinical conditions, T. vaginalis was identified by a combination of direct microscopy and culture in specimens from 330 (19.5%) of 1,691 women with vaginal discharges who were examined. Trichomonas vaginalis was isolated from 49 of 53 vaginal discharge specimens that also contained C. albicans. Therefore, the qualitative results with clinical cultures did not confirm the inhibition of trichomonads by C. albicans as shown in quantitative studies of associative growth. This result indicates that with the routine clinical isolation procedures the use of an antifungal agent in medium for culture of T. vaginalis is not necessary.