A-302 Evaluation of real-time PCR assays for detection of sexually-transmitted infections

Abstract

Background Sexually transmitted infections (STIs) have serious negative consequences for reproductive health worldwide. They are associated with infertility, premature birth and neonatal infections. Five STI pathogens, namely Trichomonas vaginalis, Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum were selected for the evaluation of three potential real-time PCR assays that can be adopted for diagnostic testing. Methods A total of 36 samples were included, consisting of genital swabs, urine, abscesses and samples provided by quality assurance programmes. DNA extraction was performed using an automated nucleic acid extraction system, abGenixTM. Commercial genomic controls and DNA extracts donated by external laboratories were used as well. The extracted nucleic acids were tested using three different assays, namely Seegene Anyplex II STI-5 Detection, Thermo Fisher Scientific customized STI Panel assay, and TIB MOLBIOL STI LightMix Modular kits, according to the manufacturers’ instructions. Results A total of 67% and 11% of the samples showed equivalent positive and negative results, respectively. However, 22% of the samples had non-concordant results. TIB MOLBIOL STI LightMix Modular kit was unable to differentiate between Ureaplasma parvum and Ureaplasma urealyticum in 9 samples. Genomic controls were tested, and Seegene Anyplex II STI-5 Detection was unable to detect lower concentrations of DNA for Trichomonas vaginalis, Mycoplasma genitalium and Mycoplasma hominis. All assays were able to detect lower concentrations of Ureaplasma parvum DNA, but detectable concentrations were higher for Ureaplasma urealyticum. Conclusions In conclusion, the performance of each assay differed according to pathogen. None of the assays offered equal performance for all pathogens. We have adopted Thermo Fisher Scientific customized STI Panel assay in our diagnostic testing due to its advantage of being user friendly and cost effective.