A 7-plex microbead-based immunoassay for serotyping Shiga toxin-producing Escherichia coli

Authors

Laurie M. Clotilde, U.S. Food and Drug Administration San Francisco District Laboratory
Clay Bernard IV, U.S. Department of Agriculture
Alexandra Salvador, U.S. Department of Agriculture
Andrew Lin, U.S. Food and Drug Administration San Francisco District Laboratory
Carol R. Lauzon, California State University
Mark Muldoon, Romer Labs Technology, Inc
Yichun Xu, Strategic Diagnostics Inc.
Klaus Lindpaintner, Strategic Diagnostics Inc.
J. Mark Carter, U.S. Department of AgricultureFollow

Date of this Version

2013

Citation

Journal of Microbiological Methods 92 (2013) 226–230; http://dx.doi.org/10.1016/j.mimet.2012.11.023

Abstract

Serotyping of Shiga toxin-producing Escherichia coli (STEC) has been contingent upon the availability of antisera. Here we describe a 7-plexmicrobead-based immunoassay to simultaneously serotype seven STECs (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 was confirmed by PCR. Except for one strain belonging to the O111 serogroup, nearly 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.