Development of a disposable cartridge real-time PCR test for detection of Chlamydia trachomatis directly from urine

Abstract

Abstract We present a PCR assay screening Chlamydia trachomatis directly from urine without pre-amplification or sample clean-up and demonstrate suitability for implementation on a disposable cartridge system. Primers and probes were designed to detect all Chlamydia trachomatis serovars with a high degree of sensitivity and specificity. The assay also incorporated a synthetic internal amplification control to monitor inhibition of the PCR reaction. The assay protocol worked directly on urine samples with initial heating to 85 °C for ten minutes, followed by a duplex realtime PCR (95 °C, 55 °C, 45 cycles) on resulting urine lysate. The test cartridge incorporated heating and liquid manipulation using pinch valves and a compressible blister pouch. Lyophilised PCR reagents were incorporated into the cartridge and were re-suspended by a 40 μL aliquot of the urine lysate. Primers were designed to screen for all Chlamydia trachomatis serovars with a high degree of sensitivity and specificity. Evaluation of the newly developed PCR assay was carried out on the LightCycler™ using urine samples previously confirmed positive or negative for the target pathogen, using the ABBOTT real-time PCR Cobas CT/NG test at a local hospital.