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Basic sciences poster session 3: ureaplasma, trichomonas and syphilis
P4-S3.05 Clinical titres and stability of Trichomonas vaginalis RNA in urine specimens
  1. M Catania,
  2. C Bennett,
  3. A Pae,
  4. B Weinbaum,
  5. D Getman
  1. Gen-Probe Incorporated, San Diego, USA

Abstract

Background This study estimated the range of concentrations of Trichomonas vaginalis (TV) present in naturally infected female urine specimens and evaluated the ability of the APTIMA Trichomonas vaginalis (ATV, Gen-Probe Incorporated) Assay to detect a clinically-relevant amount of TV cells spiked into TV-negative male and female urine samples and stored at various temperatures.

Methods Female urine samples collected as part of a prospective, multicenter US clinical trial were tested with the ATV Assay, a nucleic acid amplification test for the diagnosis of TV infection in asymptomatic and symptomatic women. To determine TV cell titres, serial dilutions of TV-positive urine samples were tested and results were compared to results from serial dilutions of a laboratory culture of TV with a known cell titre. To assess the stability of TV cells in urine samples, 10 male and 10 female urine samples from non-infected volunteer donors were spiked with a cultured strain of TV, stored at 4°C, 20°C and 30°C, and tested daily for up to 14 days with the ATV assay.

Results Of 39 randomly selected TV-positive female urine samples, the median titre in unprocessed samples was 311 cells/ml (mean=2040 cells/ml; SD=4765 cells/ml), with a range of 2–28 430 cells/ml. Of these 39, 87.2% (34/39) had a TV cell titre of ≥20 cells/ml in neat urine see Abstract P4-S3.05 figure 1. To assess stability of TV cells in urine, freshly collected male and female urine samples from volunteer donors were spiked with TV to 20 cells/ml (4 cells/reaction in the ATV assay), stored at various temperatures, and then tested with the ATV assay. For samples stored at 4°C, the ATV assay was 100% reactive for both male and female samples after 14 days of storage. For samples stored at 20°C, male samples were 100% reactive after 7 days storage, while female samples were 100% reactive after 6 days of storage. For samples stored at 30°C, 100% reactivity was obtained at 2 days storage for male samples and 4 days storage for female samples.

Abstract P4-S3.05 Figure 1

Two-phylotype population structure of global Trichomonas vaginalis isolates.

Conclusions This study shows urine samples from women infected with TV have a wide range of cell titres, with an average of ∼2000 TV cells/ml. TV can be detected for 14 days when stored refrigerated or for about 1 week at 20°C. The use of sensitive, automated molecular tests such as the ATV assay for testing urine samples should facilitate screening for TV.

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