Real-Time Polymerase Chain Reaction Detection of Trichomonas vaginalis from vaginal swabs: Validation of a Diagnostic Method and Preliminary Epidemiological Application

Abstract

Background Trichomonas vaginalis is the most common nonviral sexually trasmitted diseases (STDs) agent. For females, the diagnostic gold standard is the culture of vaginal swab, which is labour-exacting.The direct microscopic examination of vaginal secretions is the most used approach, but its sensitivity depends on the skill of the observer. Objectives We evaluated an original real-time TaqMan-based Polymerase Chain Reaction (PCR) technique.The scope of the study was to confirm the effectiveness of the molecular approach in a clinical context and to explore its relevance to an epidemiological investigation. Study Design a ß-tubulin gene was chosen as target sequence.The assay was designed to exploit the quantitative potential of the TaqMan procedure.The population sample was 583 adult females presenting at the Service from January 2005 to December 2005.Three vaginal swabs were collected from each patient, one for wet mount microscopy, one for broth culture, and one for the molecular assay. Results The prevalence was 3.3% (culture), 3.1% (microscopy), 3.8% (PCR).An excess risk was detected in the immigrant population (risk ratio by PCR = 28). Conclusions The molecular approach was the most accurate way to detect the protozoon.The real-time PCR is convenient in a busy laboratory, provided the necessary equipment is available, and it is suitable for epidemiological investigation.