A competitive immunosorbent assay for the detection of heat-stable enterotoxin of Escherichia coli.

A competitive ELISA procedure for the detection of Escherichia coli heat stable enterotoxin (ST) with monoclonal antibody has been developed. This test is 10 times more sensitive than the suckling-mouse bioassay and it is specific, simple and cheap. A set of 882 strains of E. coli isolated from man were tested both by ST-ELISA and suckling-mouse bioassay, the latter serving as the reference method. Positive results in both tests were obtained with 152 strains. The remaining strains gave negative results in both tests, with the exception of two strains, known to be ST producers, that gave negative results in the suckling-mouse assay, but gave positive results by the ELISA method.