[Rapid and simple method for the detection of shigatoxins (STxs)]

Enterohemorrhagic Escherichia coli (EHEC) is an emerged bacterial agent as the cause of bloody diarrhea and a leading cause of hemolytic uremic syndrome in children. In our country, serotype O 157:H7 is the predominant pathogen in the EHEC and the most frequently seen in human infections. The clinical disease is not associated with the STx types produced by the infecting strains. Non-O157 serotypes of EHEC also produce STxs, and infections with some non-O157 EHEC are occasionally associated with the illness caused by O157:H7. A rapid and simple enzyme immunoassay method (EIA) for the detection of STxs was established. This method is based on the use of anti-STx1 or anti-STx2 monoclonal antibody-labelled colloidal gold for detective factor and also used each anti-STx antibody for the capture antibody. The supernatant was used as the test sample after centrifugation of bacterial suspension treated with polymixin B (5,000 u/ml). These EIA-tests were specific for all supernatants of EHEC serotypes used, giving positive reactions (more than 1:16-32) by the RPLA method, and permitted the detection of ca. 203-812 pg of STx1 or STx2 in a 130 microliters applied to this test. This method will be an extremely useful tool for the detection of STxs from isolates or bacteria on selective agar-plates.