We use sorbitol EMB for primary isolation. It is just like regular EMB
but has sorbitol substitued for the lactose. As most E.coli strains are
sorbitol positive and E.coli O:157 is sorbitol negative, suspect colonies
are clear (sorbitol negative) and may be picked for further study. We use
a latex kit sold by Remel in Lanexa, Kansas 800-255-6730. The latex kit
works well to detect the O antigen, but does not confirm the H antigen. I
also read an article thatsaid E.coli O:157 also has a distinct MicroScan
Profile number, but I can't give you the reference.
G. Ned Christensen
Eugene, OR
