Multiplex, bead-based suspension array for the molecular determination of common Salmonella serogroups.
Journal of clinical microbiology 2007 Jul 18; 45(10):3323-34
Fitzgerald C C, Collins M M, van Duyne S S, Mikoleit M M, Brown T T, Fields P P
Enteric Diseases Laboratory Preparedness Branch, Division of Foodborne, Bacterial and Mycotic Diseas
We report the development and evaluation of a Salmonella O group-specific Bio-Plex assay to detect the six most common serogroups in the United States (B, C1, C2, D, E, and O13) plus serotype Paratyphi A. The assay is based on rfb gene targets directly involved in O antigen biosynthesis; it can be completed 45 mins post-PCR amplification. The assay correctly and specifically identified 362 of 384 (94.3%) isolates tested in comparison to traditional serotyping. Seventeen isolates (4.4%) produced results consistent with what is known about the molecular basis for serotype but different than traditional serotyping and five isolates (1.3%) generated false negative results. Molecular determination of serogroup for rough isolates was consistent with a common serotype in most instances, indicating that this approach has the potential to provide O group information for isolates that do not express an O antigen. We also report the sequence of the O antigen encoded rfb gene cluster from Salmonella enterica serotype (ser.) Poona (serogroup O13). When compared with other previously characterized rfb regions, the O13 rfb gene cluster was most related to E. coli O127 and O86. The O group Bio-Plex assay described here provides an easy to use high-throughput system for rapid detection of common Salmonella serogroups.