Determination of thermostable and thermolabile enterotoxins in Escherichia coli strains by genetic, biological, and immunoserological methods]

The Escherichia coli strains (75) isolated from patients suffering from diarrhea were screened for ability to produce the temperature-labile or stable toxins (ST or LT) by the different techniques (the hybridization with DNA probes, biological, enzyme immunoassay). The majority of tested strains was shown to harbor the tox-genes controlling the synthesis of ST, LT or both enterotoxins. However, the phenotypic expression of the genes was registered in only some of the strains. The hybridization with the DNA probes is noted to be most perspective in the mass screening of toxigenic strains. The DNA probe used contained the fused estA-eltB genes that makes one able to detect the genes for both enterotoxins.