Real-time PCR improve detection of Trichomonas vaginalis compared to conventional techniques

Abstract

Trichomonas vaginalis is the cause of one of the most common types of vaginitis, trichomoniasis. Clinical manifestations of symptomatic women are generally nonspecific, but include vaginal discharge, vaginitis and irritation. T. vaginalis infection has also been linked to the increased risk of human immunodeficiency virus transmission. The aim of the study was to compare a real-time polymerase chain reaction (PCR) assay with culture and wet-mount examination for the detection of T. vaginalis. This is a descriptive analytical study. Vaginal swabs from 504 female patients with suspected vaginitis were included in the study. They were subjected to culture, wet-mount microscopic examination (WM), and real-time PCR. Real-time fluorescence resonance energy transfer hybridization probe PCR assays were used in this study to test for T. vaginalis DNA, targeting the b-tubulin genes. The result of the PCR was compared with culture and wet-mount microscopy. WM were positive for T. vaginalis in 60/504 cases (11.9%) and cultures were positive for T. vaginalis in 116/504 cases (23%). Real-time PCR was done on 50/504 specimens which was randomly chosen, 33/50 (66%) cases were positive for T. vaginalis (78% sensitivity), 25/50 (50%) of them were culture and wet-mount examination positive. Of them, 1/33 (3%) were culture positive and wet examination negative, 7/33 (21%) real-time positive were negative by culture while 17/50 (34%) real-time PCR negative cases were also negative by both techniques. The time taken for PCR assay was 4 to 8 h whereas positive protozoal cultures took up to 4 days. The Real-time PCR done in this study, provide a rapid, sensitive and specific diagnosis of T. vaginalis infection.