Diagnosis of Trichomonas vaginalis infection by PCR

Trichomonas vaginalis infection is the most prevalent sexually transmitted disease in the world. It causes vaginitis, urethritis and preterm birth. It has been associated with nongonococcal urethritis in men. In this study, a polymerase chain reaction (PCR) targeting the beta-tubulin genes of T. vaginalis was developed for the detection of the organism in both vaginal swab and urine specimens from infected patients. Random urine samples were collected from 30 patients (23 females and 7 males) tested positive for T. vaginalis by wet preparation and the Inpouch T. vaginalis culture system. Two vaginal swabs were collected by each woman, first before insertion of the speculum and then after the insertion of the speculum. A previously published T.vaginalis specific primer set, (BTUB 9/2), BTUB 9 (5'' CAT TGA TAA CGA AGC TCT TTA CGA T 3'') and BTUB2 (5'' GCA TGT TGT GCC GGA CAT AAC CAT 3'') recognizing a 112-bp target within the β-tubulin gene of the T. vaginalis organism was used for this purpose. The positive result was reported 28.6% in male urine and 39.1% in female urine samples, first swab 65.2% and second swab 78.3% by wet preparation diagnosis. By the culture test, the male urine samples recorded 42.9% positive, female urine 69.6% while the first swab recorded 86.9% positive and the second swab 91.3% positive. All negative cases by culture in urine and vaginal samples were tested by PCR, which resulted as 2 cases positive in male urine samples and 5 cases were positive in female urine samples, but one case only gave positive with PCR in first swab of vaginal samples and 2 cases of second swab became positive by PCR. No statistical differences were observed in incidences among patients On conclusion the PCR assay was even more sensitive than wet preparation and culture and afforded the practical advantages of providing results.