Department of Medicine

IU Infectious Diseases Laboratory

Culture for Trichomonas vaginalis

Trichomonas vaginalis is one of the most common non-viral sexually transmitted diseases (STD) worldwide. This anaerobic protozoan, motile by means of anterior flagella and an undulating membrane, infects an estimated 180 million women worldwide with conservative estimates indicating that 6 million are infected annually in the United States . Trichomonal infections cause vaginitis with discharge, vaginal irritation and odor, cervicitis and urethritis in women and non-gonococcal urethritis and prostatitis in men . Trichomonas has been implicated in enhancing the transmission of other sexually transmitted diseases, especially HIV, and has been used as a marker for identifying asymptomatic infections such as chlamydia and gonorrhea. Asymptomatic infections are observed in approximately 50% of male and female patients iv with symptomatic infection being observed in only a small percentage of males . Due to the high frequency of asymptomatic infections, all sexually active or at-risk patients should be screened. Culture for T. vaginalis is performed in this laboratory using the In-Pouch culture system (Biomed, White City, OR). This is a two chambered system with the upper chamber available for wet-mount examination and the lower one for culture. The culture pouch is incubated at 370 C for up to 5 days post-inoculation in order to allow for expansion of the trichomonads. Motile trichomonads are visualized by reading the culture pouch under a white light microscope. An inoculum of 1-10 organisms is sufficient to cause a positive test result. This system is specific for the isolation of T. vaginalis; other trichomonas species will not replicate in this medium. This culture system is for use with vaginal and male urethral swab samples, semen, and male urine