Molecular characterisation of Trichomonas vaginalis isolates in Southwest Turkey with multilocus sequence typing and genetic structure analysis in relation to different countries

Trichomonas vaginalis, a flagellated protozoan parasite, is among the most common sexually transmitted pathogens in the world. The present study aimed to identify the genetic profiles of T. vaginalis in the southwest of Turkey with multilocus sequence typing (MLST) and to analyse the genetic structure of the parasite in a collection of isolates from different countries. The study included 27 T. vaginalis isolates from symptomatic females in Aydin, Turkey. Seven housekeeping genes of T. vaginalis were partially amplified and sequenced after genomic DNA extraction from in vitro cultures. The allele profiles and sequence types (STs) of the isolates were determined by using the MLST database (https://pubmlst.org/tvaginalis). The genetic structure and differentiation of the parasite were analysed in relation to findings from other countries by assembling the available MLST sequences. When referred to the database, a total of 22 STs, including 18 new STs were found; besides, there were two new allele types. The genetic analysis of MLST data demonstrated the presence of two main genetic structures: Type I and Type II. In addition, the neighbor-joining method also revealed that the isolates were clustered into two groups. The genetic types distributed almost equally in the Netherlands and the USA, however, the predominance of Type I was noted in Turkey and the UK. The genetic differentiation among four countries was significant (p < .05), the gene flow was relatively high between the Netherlands and the USA, in contrast to Turkey. Finally, genetic variations were originated within populations (93.8%) rather than among populations (6.2%). In conclusion, we studied the genetic diversity of T. vaginalis isolates with MLST in the southwest of Turkey and showed the origin of genetic differentiation of the parasite among different countries. The presentation of MLST profiles and genetic variance of T. vaginalis isolates will contribute to the development of new diagnostic and treatment options for the parasite.