Rapid immunodetection of Escherichia coli

A filtration flow-through design was used to develop the rapid immunodetect ion of Escherichia coli. Polyclonal anti-E. coli IgG was conjugated to smal l, 0.8 mu Blue latex beads. Cells were mixed with conjugated beads in the p resence of anti-E. coli monoclonal IgM. The suspension was then filtered th rough a 5 mu nitrocellulose membrane. The cell-containing complexes were ef fectively collected on the filter, forming a blue spot. The method produced reliable detection of E. coli at a concentration of 10(5) cells ml(-1), wh ich is a current benchmark figure for urinary tract infection (UTI) diagnos is.