Ultra-Stable Test Strip System for Multiplexed Detection of Enteric Pathogens

Diarrhea is a leading cause of death globally, especially among infants and young children with limited access to medical resources. Although accurate and timely diagnosis of the causative infectious diseases would increase survival rates and mitigate epidemic spread, the current challenges of transporting and storing sensitive diagnostics in uncontrollable environments are not economically or logistically feasible. <P> To meet this need, Intelligent Optical Systems (IOS) and collaborator, Universal Stabilization Technologies (UST), propose to create an ultra-stable, one-step immunoassay platform that can identify multiple enteric pathogens in a single sample with high sensitivity and specificity. This rapid and inexpensive point-of-care test will accurately identify one or more pathogens so that health workers can initiate the most appropriate treatments without the unnecessary risks of creating antibiotic-resistant pathogens. To encourage worldwide adoption and use, this test will also be easy-to-use, very stable with long efficacy for field deployment, sensitive and microorganism specific, and inexpensive. Existing immunodiagnostics are inadequate and impractical in the field, because they often require expensive and power-intensive refrigeration to retain efficacy in uncontrollable environmental conditions. Moreover, the effective execution of many immunoassays also requires training and experience with multi-stepped protocols, to yield meaningful results. Unfortunately, even the most basic requirements to run immunoassays, i.e. power, clean water, and training, are prohibitively expensive or impossible in developing regions with minimal education, resources, and social infrastructure.<P> In Phase I, IOS will develop a lateral flow immunoassay (LFIA) test strip format capable of detecting multiple infectious pathogens in a single sample with low incidence of false positives or negatives. UST's patented technology will preserve test strips so that full activity is retained even after prolong storage at temperatures <50oC over a two-year period. We will establish a simple, one-step protocol so that minimally trained workers can produce accurate and consistent results, even with raw stool samples. Using highly fluorescent quantum dot (QD) probes that are detectable with the naked eye, this sensitive system will yield qualitative results of the pathogens present in sample within 15 minutes. <P>In Phase II, IOS will integrate more immunoassays for other fecal enteropathogens onto the same test strip format to produce a comprehensive pathogen screen. For infectious diseases that are extremely contagious at low pathogen concentrations, we will build a small, inexpensive, portable, and rugged test strip reader for enhanced quantitative detection. In Phase II, IOS will also prepare material to include in an application for FDA approval so that the prototype system can be clinically evaluated.<P> PUBLIC HEALTH RELEVANCE: Every year, diarrhea causes the deaths of millions of people, especially children under the age of five. Numerous pathogens, including bacteria, parasites, viruses, and fungi, may cause fatal diarrhea in as little as 72 hours. In many economically, climatologically, and/or geographically challenging regions of the world, sensitive immunoassay diagnostics are unavailable because of the fragile nature of their protein reagents and the technical difficulty of performing the assays. A simple-to-use and ultra-stabilized test strip system that can accurately differentiate between several potential pathogens in a single sample would facilitate appropriate medical intervention and provide a certainty of treatment options. A multiplexed format would also eliminate the need for multiple tests, lower the unit cost, and broaden access to these critical tools, to prevent unnecessary death.