Identification of enterohaemorrhagic Escherichia coli by means of their production of enterohaemolysin.

With increasing interest in verocytotoxigenic Escherichia coli (VTEC) being associated with both human and animal infection, a simple system of rapidly identifying the majority of VTEC has been devised. This depends on the fact that most VTEC produce enterohaemolysin, which is rarely produced by non-VTEC. By employing two media, traditional sheep blood agar (SBA) and washed sheep blood agar supplemented with calcium (WSBA-Ca), enterohaemolysin-producing strains can be easily differentiated from other E. coli enabling most VTEC types, including ones belonging to serogroups other than O157, to be isolated.