[A method for specific isolation of verotoxin-producing Escherichia coli colonies].

The described colony immunoblot is a special double membrane-agar technology, which permits the specific isolation of VTEC in biological materials decided VT-positive by EIA or PCR. The produced Verotoxin (VT) is detected on the surface of the lower membrane by help of monoclonal antibodies. A direct allocation of the corresponding VT-expressing E. coli-colonies on the upper membrane is possible. So the isolation and further characterisation of potential VTEC is practicable in materials with a high microbial contamination too. This isolation method is available for the examination of VT-positive faeces and foods. In the case of foods it is necessary to work with an enrichment culture.