A comparison of three real-time PCR assays for the confirmation of Neisseria gonorrhoeae following detection of N. gonorrhoeae using Roche COBAS AMPLICOR.

Three different real-time PCR assays were evaluated as confirmatory tests for Neisseria gonorrhoeae after initial screening using the COBAS AMPLICOR Chlamydia trachomatis and N. gonorrhoeae duplex assay. The target genes used for the confirmation were the gyr, cppB and 16S rRNA genes. Analytical specificity was determined by testing 60 strains belonging to different bacterial species and/or serogroups. The primers chosen from the 16S rRNA gene for confirmation of N. gonorrhoeae were highly specific, showed no cross-reactivity with other bacteria included in the study, and had an analytical sensitivity of 1 CFU. Of 192 clinical specimens that were positive for N. gonorrhoeae according to the COBAS AMPLICOR assay, 42 were confirmed as positive using the 16S rRNA gene target, 26 were confirmed using the cppB target, and 30 were confirmed using the gyr target. It was concluded that the real-time PCR assay targeting the 16S rRNA gene is a useful confirmatory assay to complement the COBAS AMPLICOR screening test for N. gonorrhoeae.