Characteristics of Trichomonas vaginalis isolates from women with and without colpitis macularis.

Colpitis macularis, the most specific clinical sign for diagnosis of trichomoniasis, was detected by colposcopy in 52 of 118 infected women. Patients with colpitis macularis had a mean (+/- SD) of 18 +/- 20 Trichomonas vaginalis organisms/field (x 400 magnification) compared with 7 +/- 17 in patients with colpitis macularis (P less than .003). To compare possible virulence markers in isolates from women with and without colpitis macularis, isolates were analyzed for hemolytic activity, abscess production in an animal model, and adherence to cells in tissue culture. The mean hemolytic activity (relative to complete hemolysis) was 84% for 22 isolates from women with and 78% for 29 isolates from women without colpitis macularis. After subcutaneous injections in mice, abscesses were produced by 70% of isolates from patients with and 68% from patients without colpitis macularis. After a 15-min exposure, 39% of radiolabeled isolates from women with or without colpitis macularis adhered to HeLa cell monolayers. Purulent discharge, the second most useful sign for clinical diagnosis, was associated with colpitis macularis and with the number of organisms per high-power field on wet mount (P less than .01 for each comparison) but was not correlated with any experimental assay. Thus, no experimental characteristic of T. vaginalis isolates was associated with colpitis macularis or purulent vaginal discharge.