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.