Ability of commercial ligase chain reaction and PCR assays to diagnose Chlamydia trachomatis infections in men by testing first-void urine

Abstract

A total of 287 men (37.6% with symptoms of urethritis) attending a hospital-based sexually transmitted disease clinic had urethral swabs tested by culture and by direct fluorescent-antibody assay. First-void urine (FVU) was tested for Chlamydia trachomatis by commercially available ligase chain reaction (LCR) and PCR assays. By using an expanded reference standard, 35 men (12.2%) were found to be positive. By performing LCR and PCR, the infection prevalence was found to be approximately twice (11.5 and 12.2%, respectively) that determined by swab testing. The sensitivity values were 94.3% for LCR and 100% for PCR. One of the two positive specimens missed by LCR contained inhibitors. PCR produced five false-positive results and LCR produced one. Although antigen detection assays have been effective for diagnosing men who are infected with Chlamydia trachomatis by testing concentrated first-void urine (FVU) (3, 8, 10, 11, 14, 15), limitations in sensitivity have restricted the identification of infected individuals with few or no symptoms of urethritis. Both PCR (6, 9, 12, 13, 16) and ligase chain reaction (LCR) (4, 5) have been shown to be sensitive for identifying infected men by the testing of FVU. This study compared LCR and PCR detection of C. trachomatis by using commercially available kits to test FVU from 287 men attending a sexually transmitted disease clinic. Assay performance was compared to culture and direct fluorescentantibody (DFA) staining of a urethral swab collected at the same clinic visit. An expanded reference standard (9) was used as described below. The study was performed from September 1993 to February 1995 during which time 287 men were enrolled with consents which were approved by the McMaster University Research Ethics Committee Hospital Network. The men were attending a hospital-based sexually transmitted disease clinic and each had an FVU sample (20 ml) collected in a sterile 30-ml screw-cap plastic jar. A urethral swab specimen was collected by inserting a narrow-shafted cotton-tipped swab 2 to 3 cm into the urethra. The order of collection of swabs and FVU was reversed halfway through the study. The swabs were placed into transport tubes containing minimal essential medium with 5% sorbitol, 3% fetal bovine serum, and 2 mM L-glutamine at 4ЊC. The swabs were transported to the laboratory and set up in cell cultures within 24 h. FVU specimens were held at 4ЊC and tested by LCR or PCR within 3 days. Urethral swabs from the men were inoculated onto McCoy cell monolayers in 96-well microculture plates, with a blind passage and iodine staining (2). Swabs were processed and tested by DFA. The urethral swabs were smeared according to the Microtrak DFA (Syva) package insert. A sample was con

Multicenter Evaluation of the Fully Automated COBAS AMPLICOR PCR Test for Detection of Chlamydia trachomatis in Urogenital Specimens

“…While the manuscript was being prepared, two other studies reported similar results for the COBAS AMPLICOR test (14,26). These values are similar to those reported for the nonautomated AMPLICOR C. trachomatis test (2, 6, 25-28, 30, 35) and other amplificationbased C. trachomatis tests (1,6,7,9,14,18,23,25,26,30,33). Virtually identical performance was observed for urine and endocervical swab specimens from women.…”

Detection of Chlamydia trachomatis in urine samples by nucleic acid tests: comparison with culture and enzyme immunoassay of genital swab specimens

“…While many studies have examined the sensitivity of LCR or PCR testing of urine specimens, we were able to find only four reports of direct comparisons of the LCR and Roche PCR tests in the literature. In three studies, there were no statistically significant differences between PCR and LCR analyses of (3,20) found that after freezing of the urine samples, the PCR detected additional positive samples. However, in our study, the urine samples were tested by PCR prior to freezing at Ϫ70°C until tested by LCR, yet the PCR test still performed better than the LCR.…”

Inhibition of PCR in Genital and Urine Specimens Submitted for Chlamydia trachomatis Testing

“…The use of nucleic acid amplification methods such as PCR has significantly improved our ability to diagnose genital Chlamydia trachomatis infections (3). These methods also allow for the use of noninvasive urine specimens for testing which are more acceptable to patients (3,5,10,11,15). The introduction of commercially available automated DNA amplification assays has allowed more laboratories to introduce these technologies for routine testing of specimens.…”