Simplified and accurate nonradioactive polynucleotide gene probe assay for identification of enterotoxigenic Escherichia coli.

The present study describes a colony hybridization setup for identification of enterotoxigenic Escherichia coli obviating the need for advanced equipment and radioactive isotopes. With a modest laboratory arrangement, polynucleotide gene probes were produced in large quantities. The probes were labeled with digoxigenin and, after hybridization, detected with an antidigoxigenin alkaline phosphatase conjugate. With an established isotope-based oligonucleotide hybridization assay as reference, a blinded study on a large battery of enterotoxigenic and nonenterotoxigenic bacteria revealed a satisfactory sensitivity and specificity of the nonradioactive assay.