ONE-TUBE, NESTED-PCR ASSAY FOR THE DETECTION OF TRICHOMONAS-VAGINALISIN VAGINAL DISCHARGES

To shorten the time and improve the accuracy of diagnosis of vaginal t richomoniasis, a novel, one-tube, nested PCR, which targets a family o f 650-bp specific DNA repeats from the Trichomonas vaginalis genome, h as been developed. Samples were prepared by a rapid boiling method and the PCR products analysed by gel electrophoresis. A 290-bp DNA fragme nt was observed in all positive cases. No cross-reaction with any othe r pathogens, including the Pentatrichomonas hominis and Giardia lambli a used as controls, was found. Using the assay, one genome-equivalent of T. vaginalis in 20 mu l vaginal discharge can be detected and diagn osis can be made within 6 h. When 165 clinical specimens were examined by wet mount, culture and the PCR assay, 16 were found positive for T . vaginalis by both culture and PCR, whereas only nine of these 16 cas es were found to be positive by examination of met mounts. No PCR-nega tive cases were positive by wet mount or culture. This new assay appea rs to be a simple, rapid, accurate and sensitive method for the diagno sis of vaginal trichomoniasis.