Iranian Journal of Parasitology 2016. 11(4):507-514.

Molecular Characterization of Trichomonas vaginalis Strains Based on Identifying Their Probable Variations in Asymptomatic Patients


Background: The aim of this study was to identify the Trichomonas vaginalis strains/haplotypes based on identifying their probable variations in asymptomatic patients referred to Tabriz health centers, northwestern Iran.

Methods: Sampling was taken from 50-suspected women to T. vaginalis in northwestern Iran. The obtained samples were smeared and cultured. Fifty DNA samples were extracted, amplified and identified by nested polymerase chain reaction and PCR-RFLP of actin gene using two endonuclease enzymes: MseI and RsaI. To reconfirm, the amplicons of actin gene were directly sequenced in order to identify the strains/haplotypes.

Results: PCR-RFLP patterns, sequencing and phylogenetic analyses revealed definitely the presence of the G (n=22; 73.4%) and E (n=8; 26.6%) strains. Multiple alignments findings of genotype G showed five haplotypes and two amino acid substitutions in codons 192 and 211 although, no remarkable unique haplotype was found in genotype E.

Conclusion: The accurate identification of T. vaginalis strains based on discrimination of their unknown haplotypes particularly those which are impacted on protein translation should be considered in parasite status, drug resistance, mixed infection with HIV and monitoring of asymptomatic trichomoniasis in the region.


Trichomonas vaginalis; Actin gene; Genotypes; Asymptomatic infection

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