Detection of Staphylococcus Enterotoxin B (SEB) Using an Immunochromatographic Test Strip

Background: Staphylococcus aureus is one of the most important microorganisms that causes various human diseases by secreting virulence factors known as staphylococcal super antigens (SAgs). Staphylococcal Enterotoxin B (SEB) is a bacterial antigen that is responsible for food poisoning in humans. Among SEB detection methods, a lateral flow device (LFD) is ideal for rapid immunochromatographic tests because it is easy to use, requires minimal time to produce results, and does not require personnel training. Objectives: In our laboratory, the production of an immunochromatographic test strip, for the detection of SEB using a sandwich assay and a competitive method, was described; the test can detect SEB with high sensitivity. Materials and Methods: The strip assays were compared with PCR, a valid method for detection. For PCR, a specific sequence for SEB production was detected using primers designed according to GenBank sequences. Results: In total, 80 food samples suspected of SEB contamination were assessed using the two methods. Fifty-four samples were contaminated based on the PCR technique and twenty-six of those were confirmed using the strip assay. Conclusions: The sensitivity of the sandwich method was approximately 10 ng/mL and that of the competitive method was approximately 250 ng/mL. In the LFD, a highly specific monoclonal antibody used for both the sandwich and competitive methods resulted in an increased sensitivity and accuracy for the detection of a minimal SEB concentration.