Real-time PCR improves detection of Trichomonas vaginalis infection compared with culture using self-collected vaginal swabs

Infect Dis Obstet Gynecol. 2005 Sep;13(3):145-50. doi: 10.1080/10647440500068248.

Abstract

Objective: To compare a real-time polymerase chain reaction (PCR) assay with broth culture for the detection of Trichomonas vaginalis using self-collected vaginal swabs.

Methods: Self-collected vaginal swabs were obtained from adolescent and young adult African-American women participating in HIV-1 prevention programs. T. vaginalis culture was performed using the InPouch TV System. Samples for the real-time PCR assay were collected using the BDProbeTec ET Culturette Direct Dry Swab system and tested in a laboratory-developed assay which targeted a repeated sequence of the genome. Discrepant samples that were culture negative and positive in the real-time PCR assay were tested in a confirmatory PCR which targeted a different region of the T. vaginalis genome, the18S ribosomal DNA gene.

Results: Of the 524 specimens tested by both culture and real-time PCR, 36 were culture positive and 54 were positive in the real-time PCR assay; 16 of the 18 discrepant specimens were also positive in the confirmatory PCR assay. Using a modified gold standard of positive by culture or positive in both PCR assays, the sensitivity of the real-time PCR assay was 100% and the specificity was 99.6%, whereas culture had a sensitivity of 69.2% and a specificity of 100%.

Conclusions: The real-time PCR assay was sensitive and specific for the detection of T. vaginalis DNA from self-collected vaginal swab specimens. The ability to use the BDProbeTec dry swab system for the real-time PCR testing allowed for the detection of Chlamydia trachomatis, Neisseria gonorrhoeae, and T. vaginalis from a single specimen.

MeSH terms

  • Adolescent
  • Adult
  • Animals
  • Black or African American
  • DNA, Protozoan / analysis*
  • Female
  • Humans
  • Polymerase Chain Reaction / methods*
  • Sensitivity and Specificity
  • Trichomonas Vaginitis / diagnosis*
  • Trichomonas vaginalis / genetics
  • Trichomonas vaginalis / isolation & purification*
  • Vagina / parasitology*

Substances

  • DNA, Protozoan