Detection Of Chlamydia Trachomatis Antigen Research Articles

Detection of Chlamydia trachomatis Antigens in Urine as an Alternative to Swabs and Cultures

By using commercially available spectrophotometric and immunofluorescent immunoassays, Chlamydia trachomatis antigens were detected in first-void urine (FVU) sediments from 224 men attending a sexually transmitted disease clinic at a frequency of 81.6%-86.8% compared with 86.8% (33/38) positive by urethral swab culture (P less than .05). Endocervical cultures from 228 women attending a gynecology clinic yielded 92.3% (12/13) positive compared with 61.5%-76.9% for urine samples in three antigen-detection assays. Culturing urine from either gender yielded low positivity rates (23.7% for men, 15.4% for women). Defining truly infected patients as positive by culture or by any two of the three antigen tests, all assays were 100% specific. Immunodiagnostic testing of male FVU sediment appears to be a reliable, rapid, nontraumatic method for diagnosing chlamydia infection.

Efficacy of duplicate genital specimens and repeated testing for confirming positive results for chlamydiazyme detection of Chlamydia trachomatis antigen.

In an attempt to increase Chlamydiazyme (Abbott Laboratories) detection of Chlamydia trachomatis antigen and to establish the reproducibility of positive results, we carried out an investigation into the usefulness of testing duplicate specimens, of more aggressive endocervical specimen collection by using cytobrushes instead of swabs, and of the repeated testing of both specimens from patients with one or two positive results. Duplicate endocervical (female) and urethral (male) specimens, including one swab and one cytobrush specimen from 1,331 nonpregnant women, were collected from symptomatic and asymptomatic patients. Specimens were transported and tested for C. trachomatis antigen as specified by the manufacturer. Tests on all specimens from patients with positive results were repeated. Antigen was initially detected in one or both specimens from 210 (10.7%) of 1,968 patients, and repetition of the tests confirmed its presence in 198 (10.1%) of the patients, including all 183 patients in whom it was initially detected in both specimens. Initial results from at least 8 of the 12 patients with irreproducible antigen detection were most probably falsely positive. Results from 21 (10.6%) of the 198 patients for whom antigen detection was confirmed were repeatedly positive on only one specimen (9 [4.5%] on the second of the two specimens collected). Of 115 women from whom one swab and one cytobrush sample were taken and who had repeatedly positive results, antigen was detected in 7 (6.1%) only on the swab sample and in 4 (3.5%) only on the cytobrush sample. Use of the cytobrush does not appear justified with the Chlamydiazyme assay, and collection of duplicate specimens provided only a modest increase in detection of C. trachomatis. However, repeated testing of specimens when results from only one of two specimens are positive appears to be of clinical value.

Enzyme immunoassay and enzyme-linked fluoroimmunoassay for detection ofChlamydia trachomatis antigen

An enzyme immunoassay (EIA) and an enzyme-linked fluoroimmunoassay (ELFIA) utilizing monoclonal antibody to major outer membrane protein of Chlamydia trachomatis L2 were developed for rapid detection of chlamydial antigen in clinical samples. The EIA and ELFIA could detect levels of purified chlamydial outer membrane protein as low as 1.0 and 0.2 ng/ml respectively. However, when EIA and ELFIA were compared to chlamydial isolation using 160 patient samples, the sensitivity rate was 68% and 85% respectively. The sensitivity of the antigen detection method might be increased by simply using less diluted samples than in the present study. Chlamydial antigen was also demonstrated by EIA and ELFIA in 15% and 23% of culture-negative samples. The reason for these false-positive findings remains undetermined.

Detection of Chlamydia trachomatis antigens by enzyme immunoassay and immunofluorescence in genital specimens from symptomatic and asymptomatic men and women.

Chlamydia trachomatis antigens were detected in populations with the following infection prevalences: 26.5% (36 of 136) of men and 27.7% (48 of 173) of women attending a sexually transmitted disease clinic, 16.3% (53 of 324) of women attending a Planned Parenthood clinic, and 3.4% (4 of 117) of an obstetrics and gynecologic practice. Compared with cell culture of the combined female cervical specimens (15.8% prevalence), the respective sensitivities of Chlamydiazyme (Abbott Laboratories, North Chicago, Illinois) and Microtrak (Syva, Palo Alto, California) were 98.3% and 87.9%, specificities were 97.5% and 98.4%, positive predictive values were 87.7% and 92.7%, and negative predictive values were 99.7% and 97.5%. Both assays were 70.0% sensitive with male urethral specimens, and the other parameters of performance ranged between 84.0% and 97.2%. The antigen detection assays, compared with culture, performed equally well in subjects without or with clinical signs.

Solid-phase enzyme immunoassay for detection of Chlamydia trachomatis.

The prototype of a solid-phase enzyme immunoassay for the detection of Chlamydia trachomatis antigen was tested in 403 men and 135 women attending a venereal disease clinic. Culture on HeLa 229 cells was used as reference method. In men the overall sensitivity and specificity of the enzyme immunoassay was 70% and 98.5% respectively. In the 158 men with non-gonococcal urethritis the sensitivity and specificity was 73% and 96.5% respectively, in the 31 men with post-gonococcal urethritis 82% and 100%, in the 48 men with gonococcal urethritis 67% and 100%, in the 125 men with discharge but normal urinary sediment 54% and 99.1% and in the 41 men with no signs or symptoms 50% and 100%. In women the sensitivity and specificity of the assay was 70% and 92% respectively. On account of the low degree of sensitivity in both men and women and the low degree of specificity in women the prototype of the enzyme immunoassay is not yet considered suitable for clinical use. An improved model is being developed.

Enzyme immunoassay for the detection of Chlamydia trachomatis antigen in urethral and endocervical swabs.

An enzyme immunoassay technique based on the direct detection of Chlamydia trachomatis antigen in urethral or cervical swabs was used for the rapid diagnosis of chlamydial genital infection. Urethral and cervical samples from 140 patients were tested in parallel by enzyme immunoassay and cell culture using iodine staining. The direct test had a sensitivity of 92.5% and specificity of 97.2% when compared with the cell culture system. The enzyme immunoassay technique provides a rapid and simple method for diagnosing chlamydial genital infection and may be performed on a large number of samples in laboratories which do not have tissue culture facilities or a trained microscopist.