Surface plasmon resonance (SPR) as a rapid tool for serotyping of Salmonella

An SPR-based sandwich immunoassay for serotyping of Salmonella is demonstrated. The Salmonella are captured on an SPR chip using polyclonal capture antibody. SPR sensorgrams are obtained for the immunoreactions of the somatic (O) and flagellar (H) surface antigens, of the captured bacteria, to their respective antibodies. The sensorgram data are compiled to determine the antigenic formula in accordance with the Kauffmann-White scheme. Salmonella Enteritidis was completely serotyped using this SPR-based method. In addition, Salmonella belonging to serogroups B, C and D were successfully assigned to their respective serogroups. Before serotyping the bacteria are grown to a concentration of 1 × 1010 mL−1. This SPR-based serotyping provides quantitative data, and thus, eliminates the possibility of false detections as encountered in the conventional slide agglutination test (SAT). This method was also proved to work with rough strains.