Detection of positive test for Trichomonas vaginalis in oropharyngeal exudate from а patient with pharyngitis by amplification of nucleic acids: clinical case
Authors: Shevchenko O.P. , Bardov P.V. , Matsas O.Y. , Mulkina O.Y. , Vorobiova O.V. 
Published: April 2024

Trichomoniasis is the most common infectious and inflammatory disease that is mainly sexually transmitted. Trichomonads are a group of flagellated protozoa. Four species of them infect humans: Trichomonas vaginalis, Trichomonas tenax, Dientamoeba fragilis and Pentatrichomonas hominis. Among them, only Trichomonas vaginalis is considered pathogenic, while the pathogenicity of other species is debatable. According to the WHO, more than 180 million cases of urogenital trichomoniasis are reported annually. Epidemiology of urogenital trichomoniasis has not been studied enough, but the prevalence of this infection, unlike gonorrhea and urogenital chlamydia, increases in older age groups. In women with pelvic inflammatory disease, trichomonas are detected in 5.6—20.6 % of cases, in pregnant women — in 0.98—32 %, in patients with infertility — in 19.5 %, in men with inflammatory genital diseases — in 0.2—8.5 % of cases. The only reliable evidence of trichomonas etiology of the lesion is laboratory detection of the pathogen in biological materials.We describe a clinical case of a patient K., aged 29 years, with symptoms of pharyngitis, in whom urogenital trichomonads were detected in the pharyngeal and tonsillar exudate by polymerase chain reaction. During a thorough anamnesis, patient K. reported her participation in unprotected oral sex with a partner who had been diagnosed with urogenital trichomoniasis. In view of the above, patient K. was offered an oropharyngeal exudate test for sexually transmitted infections. Pharyngeal and tonsillar exudate obtained with the ThinPrep Non Gyn non-gynecological test gave a positive result for Trichomonas vaginalis using the nucleic acid amplification test. Test results for HIV, syphilis, tuberculosis, chlamydia and gonorrhea were negative. The results of the culture testing for opportunistic pathogens were also negative. The oropharyngeal swab with nucleic acid amplification test was positive for Trichomonas vaginalis.
Conclusions. Careful collection of the anamnesis of sexual life and examination of swabs from the oropharynx with the help of nucleic acid amplification test made it possible to detect Trichomonas vaginalis in the oral cavity. The patient and her sexual partner were successfully treated. This case indicates that Trichomonas vaginalis can be transmitted orally after unprotected oral sex with a partner who has been diagnosed with urogenital trichomoniasis.Given that the clinical case presented by us and the results of the diagnostic tests are not consistent with the existing recommendations of the Center for Disease Control and Prevention, further clinical and laboratory studies are advisable to determine the possibility of oral transmission of Trichomonas vaginalis during unprotected oral sex, as well as the likelihood of these pathogenic unicellular parasites being involved in the development/maintenance of inflammatory processes of the oropharyngeal mucosa.