Genotyping of Trichomonas vaginalis in rural Vellore, South India

Trichomonas vaginalis (T.vaginalis) is a globally prevalent sexually transmitted protozoan parasite associated with a wide spectrum of clinical manifestations ranging from asymptomatic infections to malodorous vaginal discharge, cervicitis, with an increased risk of cervical cancers. Molecular characterization based on actin gene polymorphism has enabled classification of T. vaginalis into distinct genotypes, facilitating exploration of genotype-specific clinical associations and geographic distribution patterns. However, data on circulating genotypes from India are lacking. This study aimed to characterize the genotypes of T. vaginalis circulating in rural South India and evaluate their associated clinical presentations.

A cross-sectional study was conducted among 600 consenting sexually active women attending the rural Obstetrics and Gynaecology clinic in Vellore, South India, between July 2020 and February 2021. T. vaginalis infection was isolated using the InPouch® TV culture system (Biomed Diagnostics, San Jose, CA, USA), polymerase chain reaction (PCR) targeting TVK3/7 gene and Seegene Allplex™ STI Essential Assay. Genotyping was performed using actin gene-based PCR followed by restriction fragment length polymorphism (PCR-RFLP) analysis with HindII, MseI, and RsaI restriction enzymes.

Prevalence of T.vaginalis was 1.5%. Four distinct T. vaginalis genotypes were identified. Genotype G was the predominant genotype (n = 6; 67%) while genotypes E, I, and N were identified in single isolates. Genotype G T.vaginalis infection presented in both symptomatic and asymptomatic women whereas genotypes E, I and N were isolated from among symptomatic participants.

This preliminary study identified four T. vaginalis genotypes (G, E, I, and N) among women in rural Vellore. To our knowledge, this is the first report describing molecular genotypes of T.vaginalis from India. Within the limitations of this study, no association was observed between genotype and clinical presentations or outcomes.