Chlamydia trachomatisantigen detection in pregnancy and its verification by antibody blocking assay

Abstract

Purpose: To detect the prevalence of genital infection caused by Chlamydia trachomatis in pregnant women and also to confirm the positive results using blocking antibody assay. Methods: Endocervical specimens were collected from 200 symptomatic and asymptomatic pregnant women attending the ANC OPD at M P Shah Medical College, Jamnagar. The samples were tested for presence of Chlamydia trachomatis antigen using the monoclonal antibody. Blocking antibody assay was used to further verify the positive results. Results: Out of 200 pregnant women, 38 (19%) were found positive for Chlamydia trachomatis antigen. Out of the 68 symptomatic patients, C. trachomatis antigen was detected in 26.4%. After verification of the positive samples 13.6% of the asymptomatic pregnant women were found to be harbouring the infection in their genital tract. Two (5.2%) out of the 38 positive samples, on verification with the blocking antibody assay, were found to be false positive by IDEIA, TM thus the specificity of the IDEIA TM being 94.8%. In patients with previous history of abortions, 27.7% were tested positive for C. trachomatis infection. Conclusions: Significant number of pregnant women shad C. trachomatis antigen in their endocervical canal, which can be easily diagnosed by this simple enzyme immuno assay having a specificity of 94.8%. Verification of positive results by antibody blocking assay can further improve the specificity of this non-culture test. Asymptomatic patients should also be screened for the infection. History of previous abortions places the patient at a higher risk for C. trachomatis infection thus such patients should be definitely tested for chlamydia infection. Key words: Chlamydia trachomatis, antigen, blocking antibody, pregnancyC. trachomatis infection, a prevalent sexually transmitted proved a definite role of C. trachomatis infection in adverse disease, is associated with complications like ectopic pregnancy outcome. [1][2][3][4] If not treated on time their newborns pregnancy, fallopian tube block and adverse pregnancy run a 20-40% risk of developing chlamydial conjunctivitis [7][8][9] outcome. [1][2][3][4] In majority of the women the infection with this and a 10-20% risk of developing chlamydial pneumonia. 7,9,10 organism is asymptomatic or with minimal symptoms. Studies from India have reported that 15% of young Therefore, screening of women at risk is highly recommended. asymptomatic women are positive for this infection. 11 In this study, an effort was made to detect C. trachomatis antigen Women at highest risk often have the least access to health from the endocervical specimens of the pregnant women and care facilities. Therefore there is a need for a rapid, simple and to verify the positive results with the antibody blocking assay accurate test to detect C. trachomatis infection, which can so as to achieve the most accurate results. be performed outside the laboratory setting when the patient is still in the clinical setting. Materials and Methods Detection of C. trachomatis infection b...

Screening of pregnant women attending the antenatal care clinic of a tertiary hospital in eastern Saudi Arabia for Chlamydia trachomatis and Neisseria gonorrhoeae infections

“…[20] Similarly, in the present study, 25% of women with a past history of abortion were positive for C. trachomatis antigen compared to 6.7% of those without such a history.…”

Comparison of clinical performance of antigen basedenzyme immunoassay (EIA) and major outer membrane protein (MOMP)-PCR for detection of genital Chlamydia trachomatis infection

“…In this study all 37 positive specimens in EIA/MOMP PCR were verified by using nested-PCR and these samples were regarded as true positive, thus the specificity of the EIA and MOMP PCR was 100%. There are some studies that reported false positive results and less specificity for antigen-EIA, indicating the need for verification of positive results by other methods such as DNA amplification ( 16 , 17 ). The variable performance of EIA for detection of C.trachomatis might be due to patient characteristics such as gender and specimen type ( 17 , 18 ).…”

Detection of <i>Chlamydia trachomatis</i> and <i>Neisseria gonorrhoeae</i> in Egyptian Women Suffering from Infertility

“…They found that the ELISA sensitivity was (56.25%) and specificity was (64.81%) and they said that the reevaluation of ELISA depending upon multiple tests as gold standard might increase its sensitivity and specificity [8]. Another study found that the ELISA method has a specificity of 94.8% and verification of positive results can further improve the specificity of this test [9]. PCR procedure also could be suitable for the confirmation of ELISA results, as it has a high concordance rate compared to the rapid test [10].…”