Comparison of two methods for detection of Chlamydia trachomatis and Ureaplasma urealyticum in male reproductive tract

Objective To investigate the value of clinical application of simultaneous amplification and testing of RNA (SAT-RNA) for detecting Chlamydia trachomatis (CT) and Ureaplasma urealyticum (UU) by comparing with the polymerase chain reaction testing of DNA (PCR-DNA) method. Methods Specimens from both urethra swab and the first avoid urine which should be at least one hour after the previous urination were collected from 163 men who were scheduled for in vitro fertilization and embryo transfer (IVF-ET) treatment due to female factors at Center for Reproductive Medicine, Shengjing Hospital of China Medical University during the period of April 2016 to April 2017. Among the 163 men, 109 simultaneously provided semen that was collected after 3-7 days of sexual abstinence for the testing. Urine and semen specimens were detected for CT and UU with SAT-RNA, while urethra swab specimens were detected for CT and UU with standard PCR-DNA. Detection results of the SAT-RNA were compared with those of the PCR-DNA method. Results The positive rate of UU in the urethra swab detected with PCR-DNA and that of UU in the urine with SAT-RNA were 47.24% and 47.85%, respectively, and the coincidence rate was 93.25%. In addition, the positive and negative coincidence rates were 93.51% and 93.02%, respectively, and the concordance between the two methods was very good (Kappa=0.865). On the other hand, the positive rate of CT in the swab specimen tested with PCR-DNA was 3.07% and that of CT in urine with SAT-RNA was 4.29%, and the coincidence rate was 97.55%. Moreover, the positive and negative coincidence rates were 80.00% and 98.10%, respectively, and the concordance between the two methods was good (Kappa=0.654). Regarding SAT-RNA detection of UU in the urine and semen specimen of the 109 patients, the positive rates of UU in the urine and semen specimens were 50.46% and 44.95%, respectively; and the coincidence rate between the two specimens was 88.99%. In addition, the positive coincidence rate and the negative coincidence rate was 93.88% and 85.00%, respectively, and the concordance between the two specimens was good (Kappa=0.780). Similarly, SAT-RNA detection of CT in the urine and semen specimens showed the positive rate was 5.50% and 3.67%, respectively; and the two specimens showed 98.17% coincidence rate. The positive and negative coincidence rates were 100.00% and 98.10%, respectively, and the concordance was also good (Kappa=0.791). Conclusion SAT-RNA detection of CT and UU in the urine specimen showed good concordance with the PCR-DNA detection of CT and UU in the urethra swab specimen. In addition, the concordance was also good between the urine and semen specimens detected with SAT-RNA. These results indicate that, as a less invasive and equally accurate procedure, SAT-RNA may be more suitable for clinical application.