High Affinity DNA Aptamer Reagents to Detect Shigella spp. and Non-Typhoidal Salmonella

Operational Technologies Corp. (OpTech) proposes to screen its existing patented Salmonella enterica DNA aptamers (U.S. Application No. 13/136,820, issued) against a number of typhoidal and non-typhoidal Salmonella enterica serovars to determine the level of crossreactivity with the goal of detecting only non-typhoidal Salmonella. Aptamers have demonstrated the potential for greater affinity (assay sensitivity), specificity and lot-to-lot reproducibility versus comparable antibodies. If extant Salmonella aptamers prove to be specific to non-typhoidal serovars, they will advance to sandwich ELISA-like (ELASA) aptamer plate assay developmentand lateral flow (LF) aptamer-quantum dot(Qdot) strip development which the P.I. pioneered (Bruno, Pathogens 3:341-355, 2014and Curr. Bionanotechnology1(2):80-86, 2015).If new Salmonella aptamers are required, they will be developed along with Shigella spp. aptamers against whole bacterial cells and immobilized recombinant surface proteins which will undergo negative selection against unwanted species and then be adapted to ELASA and aptamer-Qdot LF strip assays.The expected result will be robust aptamer reagents with long shelf lives when lyophilized and sealed even in tropical environments that exhibit superior assay sensitivity and specificity for Shigella spp. and non-typhoidal Salmonella in fecal samples and which can be used in a variety of assay formats for DoD and civilian medical communities.