Low-Cost Instrument-free Point-of-Care Diagnostic for Neisseria gonorrhoeae

点击翻译按钮获取中文摘要

Abstract Neisseria gonorrhoeae (GC) is the second most common cause of bacterial sexually transmitted diseases (STD) with an estimated world prevalence of 78 million. Approximately 820,000 cases occur annually in the U.S. but over half are unreported, and rates continue to rise as indicated by a 10.5% increase from 2010 to 2014. GC is a major cause of pelvic inflammatory disease (PID) that can lead to tubal factor infertility, ectopic pregnancy and chronic pelvic pain. GC also facilitates the transmission of HIV-1 infection. While we rely on antibiotics to treat GC infections, empiric therapy has fueled the already problematic issue of drug-resistant GC in the U.S. and the world. The main obstacle to stemming the spread of GC infections is the lack of a point-of- care (POC) diagnostic that could provide surveillance and early detection, reducing infection rates and sequelae. Current GC diagnostics rely on commercial nucleic acid amplification tests (NAATs) that are expensive, require equipment and highly trained operators, take a day to days for results, and can result in loss to follow up of patients. Thus, current NAATs are not suitable at the POC. Our team comprised of Drs. Dean and Gaydos, experts on STDs and POC development, and Diassess, a startup company with proprietary technology for POC diagnostics, have preliminary data showing that we: 1) can rapidly extract GC nucleic acids from endocervical swabs with no instruments or trained operator in a prototype Sample Preparation Module; 2) have an instrument-free multiplexed Detection Module for colorimetric detection of GC nucleic acids; 3) have a limit of detection of 10 organisms/assay; 4) have validated assays to detect GC strains and assays to detect human RNA/DNA with no cross reactivity with other STD pathogens; and 5) have shown that our system can detect GC reliably in clinical endocervical swabs that are know positive by a commercial NAAT. We will expand on our preliminary studies with the following aims. Aim 1: Using the expanding aggregate of reference and clinical GC genome sequences, we will refine our assays, replacing failed assays as needed, and ensure that our assays detect diverse GC clinical strains without cross-reactivity with STD pathogens or common vaginal/cervical species; Aim 2: Optimize sample preparation chemistry for nucleic acid extraction from urethral, vaginal and endocervical swabs, assay design and colorimetric chemistry for these swab types, without false negative or positive results from interfering substances; Aim 3: We will evaluate the sensitivity and specificity, and positive and negative predictive values of our fully-integrated system (the combined Sample Preparation Module with Detection Module) compared to commercial NAATs. By the end of Phase II, we will be poised to manufacture and use our rapid (<35 min), inexpensive, user-friendly, instrument-free, sensitive and specific GC POC test for clinical trials in the U.S. to obtain FDA regulatory clearance. Our overall goal is to deploy our GC POC diagnostic for use in doctor’s offices, small to large city and rural clinics, teen, family and STD clinics, ERs and hospital clinics, other testing sites, and resource-constrained settings around the world.