(P81) Improving Gonorrhoea Molecular Diagnostics: Genome Mining-Based Identification of Identical Multi-Repeat Sequences (IMRS) in Neisseria gonorrhoeae Genome

Background: Curable sexually transmitted infections (STIs)–Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Treponema pallidum and Trichomonas vaginalis are a major cause of poor pregnancy outcomes. The infections are asymptomatic in pregnant women and a syndrome-based approach of testing and treatment leads to missed diagnosis and lack or inadequate treatment. Culture followed by microscopy, a commonly used diagnostic methodology in low middle income countries (LMICs), is inadequate and time consuming. The gold-standard Nucleic Acid Amplification Tests (NAATs) require high-infrastructure settings and point of care tests (POCTs) are limited to immunoassays with sensitivities and specificities insufficient to diagnose asymptomatic cases. This necessitates the development and validation of newer assays.



Methods: In our studies, we have identified new diagnostic target biomarker regions for NG using identical multi repeat sequences (IMRS) algorithm-based genome mining, developed them as DNA amplification primers to design better diagnostic assays.



Results: The novel assay, NG IMRS-PCR had an analytical sensitivity of 0.006 pg/μl and was ~100 times more sensitive compared to the 16S rRNA PCR assay with analytical sensitivity of 4.3096pg/μl. The assay was also demonstrated with clinical samples consisting of bio-banked urethral swabs.



Conclusion: The designed assay can potentially be used to screen asymptomatic infections due to its increased sensitivity and specificity. Put together, algorithm-based de novo genome mining of IMRS as amplification primers can serve as a novel platform technology for developing ultrasensitive diagnostics for NG genome and potentially a wide range of infectious pathogens. In addition, there is a potential to implement this concept in miniaturized, isothermal, microfluidic platforms and laboratory-on-a-chip diagnostic devices for highly reliable point-of-care testing.