Endosymbionts in Trichomonas vaginalis pathogenicity

Trichomonas vaginalis is a microscopic parasite that causes one of the most common sexually transmitted infections (STIs) worldwide. Surprisingly, this parasite does not always act alone. It can harbor tiny "partners", specifically a virus called T. vaginalis virus (TVV) and a type of bacterium known as Mycoplasma hominis. These hidden passengers, called endosymbionts, may affect the severity of the infection, but researchers still know little about their exact role. In a previous research project, we collected T. vaginalis isolates directly from patients. While some of these isolates naturally carry endosymbionts, others do not. Using this unique collection, we are now investigating how these hidden companions affect the parasite`s ability to cause damage. We will remove the endosymbionts under laboratory conditions and observe the changes occurring in T. vaginalis. A special focus of our study is on M. hominis. We are comparing strains of this bacterium found inside T. vaginalis with those isolated from individuals who were not infected with T. vaginalis. This comparison can reveal whether their symbiosis makesthe bacteria or parasites moredangerous. To gain deeper insights we will also analyze vaginal swabs from sex workers, paying particular attention not only to the presence of T. vaginalis, but also to that of M. hominis and a related group of bacteria called Ureaplasma, which are often overlooked in routine STIs screenings. Our goal is to determine how common these infections are in Austria and whether routine testing for them should be recommended. We will study the effects of T. vaginalis strains with and without endosymbionts on human vaginal cells under laboratory conditions, evaluating the virulence of parasites and the response of the immune system. Additionally, we will investigate specific Mycoplasma genes in order to understand what makes some strains more harmful than others. This is the first study to directly compare the same parasite strains before and after removing their hidden companions, allowing us to elucidate the role of these endosymbionts in infection. Our findings will improve our understanding of trichomoniasis and allow for improved diagnostics, particulary in high-risk groups, like sex workers. In summary, this project sheds light on the unseen microbial partnerships that may influence the severity of a common but often underestimated infection, helping to advance future diagnosis and treatment.