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Andrew Hardick 1 , Justin Hadick 1 , Rebecca Miller 1 , Billie Jo Wood 1 , Thomas C. Quinn 1,2 , Charlotte A. Gaydos 1

Comparison between the research GEN-PROBE® APTIMA formatted assay for rRNA (AMP-TV) and a real-time PCR, B-TUB FRET, for the detection of Trichomonas vaginalis. Andrew Hardick 1 , Justin Hadick 1 , Rebecca Miller 1 , Billie Jo Wood 1 , Thomas C. Quinn 1,2 , Charlotte A. Gaydos 1

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Andrew Hardick 1 , Justin Hadick 1 , Rebecca Miller 1 , Billie Jo Wood 1 , Thomas C. Quinn 1,2 , Charlotte A. Gaydos 1

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  1. Comparison between the research GEN-PROBE® APTIMA formatted assay for rRNA (AMP-TV) and a real-time PCR, B-TUB FRET, for the detection of Trichomonas vaginalis Andrew Hardick1, Justin Hadick1, Rebecca Miller1, Billie Jo Wood1, Thomas C. Quinn1,2, Charlotte A. Gaydos1 1- Johns Hopkins University Division of Infectious Diseases Baltimore, MD 2- NIAID, NIH, Bethesda, MD Abstr. No. 710 Code. WP-131

  2. Introduction • Trichomonas vaginalis (TV), the most prevalent non-viral STI in the world, is a major cause of urethritis, vaginitis, and cervicitis • Estimated that in the United States alone, 3 million women contract the infection every year, less is known about the prevalence in men • NAATs (nucleic acid amplified tests) are powerful new assays for the detection of TV

  3. Objectives • Compare two assays for the detection of Trichomonas vaginalis • Gen-Probe APTIMA formatted assay for rRNA (AMP-TV) research only • B-TUB FRET, a real-time PCR assay targeting the β-tubulin gene

  4. Methods • 290 men and 325 women were screened in two STD clinics • Male urine and duplicate self- administered female vaginal swabs were collected • Samples tested by two methods • Processing and testing for AMP-TV was done following Gen-Probe’s instructions • Samples were extracted by Roche MagNAPure-LC-robot and tested by B-TUB FRET PCR (Hardick et al. JCM 2003)

  5. Methods Con’t • Discordant samples • Retested by: • AMP-TV • B-TUB FRET • Wet Prep for motile TV QNS • Tested by an alternate PCR using primers TVK3 and TVK4 • True positive samples • Defined as 2 positive results by 2 different tests

  6. Initial Results B-TUB FRET + _ + _ AMP-TV Initial AMP-TV Sensitivity 96.7% (59/61) Specificity 97.3 % (535/550) PPV 79.7 % (59/74) NPV 99.6% (535/537)

  7. Initial Results by Gender Females Males B-TUB FRET + B-TUB FRET + AMP-TV + AMP-TV + Initial AMP-TV Females Initial AMP-TV Males Sensitivity 98.0 % (49/50) Specificity 95.6 % (259/271) PPV 80.3 % (49/61) NPV 99.6% (259/260) Sensitivity 90.1% (10/11) Specificity 98.9 % (276/279) PPV 76.9 % (10/13) NPV 99.6% (276/277)

  8. Results of Discordant Testing: Males True positive: Defined as 2 positive results by 2 different tests

  9. Results of Discordant Testing: Females

  10. Resolution of Discordant Results • Samples 10 and 11 were resolved as true negative because they both were wet preparation negative and had negative repeat results by AMP-TV and B-TUB assays • Sample 12, which was QNS for further testing, was resolved as a true negative, since the wet preparation for TV was negative

  11. Discordant Resolution Results Truly Infected + _ + _ AMP-TV Sensitivity 98.6% (69/70) Specificity 99.1% (536/541) PPV 93.2 % (69/74) NPV 99.8% (536/537) Resolved AMP-TV

  12. Resolved Results by Gender Females Males Truly Infected + Truly Infected + + AMP-TV + AMP-TV Resolved AMP-TV Females Resolved AMP-TV Males Sensitivity 98.2% (56/57) Specificity 98.1 % (259/264) PPV 91.8 % (56/61) NPV 99.6% (259/260) Sensitivity 100% (13/13) Specificity 100% (277/277) PPV 100% (13/13) NPV 100% (277/277)

  13. Conclusion • High overall T. vaginalis prevalence was found in our study population • Overall prevalence was 11.5% • Female prevalence was 17.8% • Male prevalence was 4.5% • Female vaginal swabs and male urine samples are non-invasive specimens which can be easily obtained and tested in amplified tests for T. vaginalis • Specificity for both assays was excellent

  14. Conclusion • Excellent initial sensitivity for Gen-Probe AMP-TV for T.vaginalis • 96.7% Overall • 98.0% Female • 90.1% Male • Excellent resolved sensitivity for AMP-TV • 98.6% Overall • 98.2% Female • 100% Male • In this study, the TMA-TV research assay was a valuable sensitive and specific assay for detection of T.vaginalis

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