A rapid, accurate, and easy-to-use diagnostic assay for STIs

Wong, Season

Abstract

The aim of this application is to develop a rapid, easy-to-use, and inexpensive multi-sample diagnostic system to identify sexually transmitted infection (STI) pathogens, such as Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) in non-traditional healthcare settings. According to the CDC, chlamydia and gonorrhea, caused by C. trachomatis and N. gonorrhoeae, respectively, are the first and second most frequently reported STIs in the US and likely the rest of the world. These STIs are often under-diagnosed, leading to delayed treatment, continued spread and higher public healthcare costs (~$16 billion annually). As a result of their prevalence and long term health consequences, there is a need for rapid, sensitive methods of detecting STIs in order for patients to get results and treatment immediately. It is important that patients receive results and initial consultation or treatment during the first patient visit, as they rarely return for a second visit. Point-of- care (POC) tests are an important strategy to address the STI epidemic, and because many affected by STIs (young and/or poor) often have limited access to traditional healthcare, POC tests that can be performed in non-traditional settings (university clinics, community public health care clinics, jails, detention centers) could greatly reduce STIs.
The aim of this application is to develop a rapid, easy-to-use, inexpensive diagnostic system for identifying STI pathogens such as CT and NG. The system will combine AI Biosciences, Inc.'s novel nucleic acid extraction cartridge and a rapid real-time thermal cycler to form a multi-sample system for use in many non-traditional healthcare settings. In Phase I, a high performance, low-cost self-contained nucleic acid extraction and purification cartridge will be developed to perform a 10 min. extraction. The extracted NA samples will be placed in an thin-walled PCR card and amplified using an innovative water based cycler to perform rapid (20 min for 40 cycles) multiplexed real-time polymerase chain reaction (PCR) for CT and NG targets. We will demonstrate that the entire assay can be completed in less than 30 min. The proposed work will be carried out in collaboration with STIs and fluidic/thermal characterization experts. Our sample preparation cartridge and the PCR technologies are highly suitable for parallel, automated sample processing. This is a substantial advantage over other integrated systems being developed as all of them can only process one sample at a time, making several units necessary to meet the minimum throughput demand. The successful development and commercialization of our technology will impact how sophisticated molecular diagnostic assays can be implemented in non-traditional healthcare settings.

Public Health Relevance

Chlamydia and gonorrhea are the most common sexually transmitted infections (STIs) in the US, causing serious long term health problems such as sepsis, stricture disease, pelvic inflammatory disease (PID), ectopic pregnancy and infertility. This project will advance the development of a POC multi-sample molecular diagnostic device for the rapid and inexpensive screening of STIs in non-traditional healthcare settings. AI Biosciences, Inc. will develop a low-cost portable nucleic acid (NA) extraction cartridge to deliver highly purified NA from urine and swab samples for real-time PCR amplification using a very low cost, automated, and rapid cycler to 8 reactions in under 20 min. Combining self-contained high quality NA extraction and rapid real-time thermal cycling will yield a 30-min molecular test that can identify two major STI pathogens in order for patients to receive immediate treatment before they leave a healthcare facility. After successful proof-of-concept work in Phase I, we aim to fully automate the system in Phase II.