Biological and Biochemical Studies for Characterization of Some Egyptian Trichomonas vaginalis Isolates

Background: Trichomoniasis has important medical, social and economical implications regarding its serious potentially associated complications, with the possibility of HIV acquisition and transmission. T. vaginalis is a very complex organism. Studying the variation in some biological and biochemical properties of the parasite can be used for characterization of the parasites. Objective: For the characterization of T. vaginalis infecting Egyptian female patients, the growth kinetics of 20 isolates, their pathogenicity, metronidazole susceptibility and electrophoretic protein patterns, were correlated with the recorded clinical manifestations associated with these isolates. Methodology: Positive samples for T. vaginalis were cultured on modified Diamond`s medium. For growth pattern study, trophozoites were counted for each isolate every 24 hours for seven days. The pathogenicity assay was performed using intra-peritoneal inoculation in mice. The isolates susceptibility to different concentrations of metronidazole was recorded by determining the minimal lethal concentration (MLC) and trophozoites viability. The biochemical variability of the studied isolates was performed using 2-dimensional electrophoresis. Results: A broad experimental variability was recorded among the 20 T. vaginalis isolates. There was a clear relationship between 3 isolates obtained from patients with severe vaginitis and the different parameters studied. These isolates had the highest number (20-25 organisms/HPF) in wet mount of vaginal discharge, and the shortest generation time (6:34-7:31 hours); they were also highly pathogenic to mice. Only one isolate (no. 5) proved to be metronidazole resistant. The use of the first dimensional native-polyacrylamide gel electrophoresis (Native-PAGE) demonstrated the presence of some differences. The isolates were classified into two groups according to their proteins net charge. All samples in each group were considered as one isolate. However, when the 2-dimensional electrophoresis (SDS-PAGE) was applied, five different groups could be identified according to proteins molecular weights. Conclusion: There is a broad experimental variability among the studied Egyptian T. vaginalis isolates regarding growth kinetics, metronidazole drug susceptibility, degree of pathogenicity, as well as the electrophoretic protein patterns.