Purpose: Simple and rapid methods to detect and identify these pathogens are needed to help confirm these serogroups. Latex agglutination assays were developed for detection of the top six non-O157 STECs.
Methods: Immunoglobulins (IgG) were affinity purified from rabbit antisera and covalently immobilized onto polystyrene latex particles. The optimum conditions for the agglutination assay consisted of utilizing 20 µl of latex-IgG reagent containing 2.0–2.8 mg IgG in a 0.5% latex suspension.
Results: Agglutination was observed instantly after mixing the colonies with the latex-IgG indicating positive reactions for the target strains. This method detected and helped confirm the target serogroups. Over 100 target and non-target strains were tested in more than 3,000 test replicates. The anti-O103 and anti-O145 latex reagents showed cross-reactions with O26 strains while anti-O26 cross-reacted with serogroup O103. The latex-IgG reagents are stable for at least one year.
Significance: The latex-IgG reagents can be used for identification of presumptive positive non-O157 STEC colonies. The method of preparation of the latex reagents can also be utilized to prepare these types of reagents for other STEC serogroups and other pathogens to ensure safe foods to consumers.