Flow cytometry for the detection of enterohaemorrhagic Escherichia coli O157: H7 with latex beads sensitized with specific antibody

Abstract

To detect low concentrations of enterohaemorrhagic Escherichia coli O157: H7 rapidly, flow cytometry (FCM) was carried out with specific IgG-sensitized latex beads (IgG-Lx). It was found that test samples for FCM can be prepared for much shorter periods by culturing E. coli O157: H7 in trypto-soya broth at 42°C and by treatment with 0.5 % formalin at 37°C. FCM with IgG-Lx performed with E. coli O157: H7 prepared by such a procedure revealed that the lowest number of E. coli O157:H7 prepared in pure culture detected by FCM was 103/ml. Because similar findings have already been reported by FCM with immunomagnetic beads, FCM with IgG-Lx is also suggested to be a valuable technique to detect low numbers of E. coli O157:H7 rapidly in food stuffs.