Genotyping of Trichomonas vaginalis isolates from Egypt

Abstract

Background: Trichomoniasis is the most prevalent non-viral sexually transmitted infection worldwide. The outcome of infections is governed by several parasite and host factors. Molecular typing methods revealed two-type population structures for T. vaginalis, type I and type II that may differ in pathogenicity, drug resistance, and clinical presentation. Objective: To elucidate the genotype of the Egyptian isolates of T. vaginalis using multilocus sequence typing (MLST). In part, this study aims to evaluate possible relationship between genotypes and growth kinetics, metronidazole (MTZ) susceptibility and clinical presentation. Patients and Methods: Three hundred vaginal washouts were collected from Egyptian women patients aged 20-45 years suspected of having trichomoniasis. Microscopically, positive samples were cultured on modified trypticase yeast extract maltose (TYM) medium and isolates were submitted to MLST targeting three housekeeping genes namely tryptophanase (p1), alanyl tRNA synthetase (p8) and DNA mismatch repair protein (p13). Results: Of the 300 samples collected, 12 (4%) proved positive for T. vaginalis by wet mount examination and culture. MLST proved that Egyptian isolates comprised two types, genotype I, constituting 70 % of the isolates and genotype II, 20 %. Mixed infection was detected in 10% of cases. No correlation was found between genotype and growth kinetics, MTZ susceptibility and clinical presentation. Conclusion: MLST is important in investigating the genetic diversity of T. vaginalis Egyptian isolates. It is recommended that a future larger multicenter study is carried out, whereby a larger number of isolates obtained from both females and males is investigated for a complete picture of genetic diversity and epidemiology.