Detection of sexually transmitted disease-causing pathogens from direct clinical specimens with the multiplex PCR-based STD Direct Flow Chip Kit

Pathogens causing sexually transmitted diseases (STDs) include viruses, bacteria, and parasites. The ability to rapidly and efficiently detect these pathogens in a single reaction still remains a health challenge. The aim of this study was to evaluate the clinical reliability and accuracy of the STD Direct Flow Chip Kit (Vitro, IVD-EC approved), which can simultaneously detect up to 9 different species of STD pathogens at once. This kit enables direct analysis-direct-PCR-of clinical specimens (urine, semen, endocervical, urethral, nasopharyngeal, and perianal swabs) without DNA purification for the following pathogens: Chlamydia trachomatis (serovars A-K and L1-L3), Haemophilus ducreyi, Herpes Simplex Virus (Types I and II), Mycoplasma genitalium, Mycoplasma hominis, Neisseria gonorrhoeae, Treponema pallidum, Trichomonas vaginalis, and Ureaplasma. The Anyplex (TM) II STI-7 Detection Kit (Seegene, IVD-EC) was used as the reference's method. Existing discordances were resolved using either a third molecular assay or DNA sequencing. Clinical performance was evaluated at two different stages: (i) from purified DNA of three hundred and fifty-eight clinical specimens with a diagnostic sensitivity (SE) and specificity (SP) of 99.4% and 100%, respectively, and an agreement of 99% (kappa index, kappa = 0.97) with the reference's method and; (ii) by direct-PCR from six hundred and thirty-three specimens rendering SE, SP, and agreement values of 98.4%, 99.9%, and 98.0% (kappa = 0.95), respectively. The STD Direct Flow Chip Kit constitutes a promising alternative to routine procedures in diagnostic, allowing direct analysis of specimens and enabling the detection of a broad panel of pathogens.