Background: Trichomonas vaginalis is the most common non-viral sexually transmitted infection (STI) in the world. Trichomoniasis is an important risk factor for herpes simplex type II infections, human immunodeficiency virus (HIV) acquisition and transmission, pelvic inflammatory disease and cervical neoplasia. Studying the variation in growth patterns of the parasite can be used for biological characterization of the parasites and might be related to the severity of clinical presentation.
Aim of the Work: Study the growth kinetics of Egyptian Trichomonas vaginalis isolates in term of log phase, growth peaks reached, division rate and generation time of each isolate and correlation of such parameters with the clinical presentation of the patients, if any.
Material and Method: The study was carried on 300 vaginal washouts collected from Egyptian women patients aged 20-45 years suspected for trichomoniasis. Positive samples for Trichomonas vaginalis were cultured and sub cultured on modified Diamond's medium. Growth kinetics for each isolate was done by inoculated 104 trophozoites/ml into 2 tubes containing 10 ml of sterile culture medium followed by counting the trophozoites every 24 hours over seven days using a hemocytometer. Growth curves were done for each isolate by plotting the parasites numbers against the time. Division rates and generation times were calculated for each isolate.
Results: Out of the 300 collected samples, twelve were found positive for Trichomonas vaginalis trophozoite by wet mount examination and culture technique. Comparison of the growth kinetics of the twelve Trichomonas vaginalis isolates revealed a salient difference among all isolates after 48 to 96 hours. Isolates 1, 2, 6, 8 and 10 had a log phase of 48 hours. Isolates 4, 5, 7, 11 and 12 had a log phase of 72 hours. Isolates 3 and 9 had a log phase of 96 hours. The fast growing isolates of Trichomonas vaginalis reached maximum growth after 48 hours and the highest yield was observed in isolate 10 (150.25±3.13). Slowly growing isolates reached a maximum after 96 hours with the lowest yield in isolate 3 (40.5±21). Regarding the clinical presentation, isolates 1, 2, 3, 4, 5 and 11 showed mild discharge and congested cervix. Isolates 6, 7, 8, 9, 10, and 12 showed profuse discharge with varying clinical findings on gynecological examination. Isolate 10 had the most severe pathology with cervical erosion. Isolate 9, 12 showed bleeding during examination, isolate 8 showed vaginal ulcer while isolate 6 showed just erythema of the vagina.
Conclusion: Comparison of the growth kinetics of the twelve Trichomonas vaginalis isolates revealed a salient difference among all isolates after 48 to 96 hours. Regarding the clinical presentation, no clear correlation was found between the growth kinetics and clinical presentation of the patients. Methods other than growth kinetics such as genotyping and determination of genetic variability are needed to verify the relation between isolates of Trichomonas vaginalis and clinical presentation.