ARS | Publication request: A 7-plex microbead-based immunoassay for serotyping Shiga toxin-producing Escherichia coli

Submitted to: Journal of Microbiological Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 30, 2012
Publication Date: December 7, 2012
Citation: Clotilde, L.M., Bernard IV, C., Salvador, A., Lin, A., Lauzon, C., Muldoon, M., Xu, Y., Lindpaintner, K., Carter, J.M. 2012. A 7-plex microbead-based immunoassay for serotyping Shiga toxin-producing Escherichia coli. Journal of Microbiological Methods. 92(2):226-230. doi:10.1016/j.mimet.2012.11.023.

Interpretive Summary: Some types of E coli bacteria produce disease in humans by releasing Shiga toxin. The seven most common Shiga toxin producing E coli are known as O26, O45, O103, O111, O121, O145, and O157. Control of these bacteria is dependent on detecting them, and in the case of outbreaks it is very helpful to know which type is present. We have developed a test that determines which of the 7 most common types of E coli are present. Our new test gave the correct result on 78 of 79 strains of Shiga toxin producing E coli.

Technical Abstract: Serotyping of Shiga toxin-producing Escherichia coli (STEC) has been contingent upon the availability of antisera. Here we describe a 7-plex microbead-based immunoassay to simultaneously serotype seven STEC (i.e., belonging to serogroups O26, O45, O103, O111, O121, O145, and O157) by the Luminex xMAP® technology. This technology presents many advantages: Its multiplexed format (up to 100 analytes) saves time, reagents, and test sample, and many regulatory agencies currently utilize this platform for other assays. In this study, a total of seventy-nine STEC strains belonging to the 7 different serogroups of interest were tested. These strains had been previously serotyped and their serogroup confirmed by PCR. Except for one strain belonging to the O111 serogroup, all strains (i.e., 98.7%; 78/79) were correctly identified on the Bio-Plex 100 instrument in less than 4 h. This newly developed microbead-based immunoassay could be extended to include other STEC serogroups, virulence factors, and/or bacterial species.