Molecular typing of the actin gene of Trichomonas vaginalis isolates in Tehran, Iran

Trichomonas vaginalis is a protozoan parasite that causes trichomoniasis with worldwide distribution. This study evaluated actin genotypes of T. vaginalis isolates using PCR–RFLP and sequence analysis in Tehran, Iran. Overall, 850 vaginal samples were collected from women admitted to hospitals affiliated with the Iran University of Medical Sciences in Tehran from 2020-to 2021. The samples were examined by wet mount and cultured. The parasites were harvested, and PCR–RFLP was performed using three endonuclease enzymes of HindII, MseI, and RsaI on all T. vaginalis isolates. Digestion patterns were then compared, and the genotype of these isolates was defined. The PCR products were sequenced. Overall, 12 (1.4%) isolates of T. vaginalis were identified from 850 vaginal samples collected. The most common genotypes were genotype E, seven (58.3%) and genotype G, three (25%), followed by genotype I, two (%16.7), using PCR–RFLP patterns and sequencing. No pattern indicative of mixed infection was found. PCR–RFLP is a proper technique to detect different T. vaginalis isolates, and noticeable polymorphism was found between isolates. Genotype E was the most common genotype in the studied group. The phylogenetic analysis indicated the T. vaginalis genotype E isolates in a distinct group compared to the genotypes G and I that evolved from a common ancestor.