Real-time PCR improves detection of Trichomonas vaginalis infection compared with culture using self-collected vaginal swabs.
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.
Caliendo
A M
AM
Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA. acalien@emory.edu
Jordan
J A
JA
Green
A M
AM
Ingersoll
J
J
Diclemente
R J
RJ
Wingood
G M
GM
D000293:Adolescent; D000328:Adult; D001741:Black or African American; D000818:Animals; D016054:DNA, Protozoan / Q000032:analysis*; D005260:Female; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D014247:Trichomonas Vaginitis / Q000175:diagnosis*; D014246:Trichomonas vaginalis / Q000235:genetics / Q000302:isolation & purification*; D014621:Vagina / Q000469:parasitology*
D016054:DNA, Protozoan