Detection of thermolabile enterotoxin of Escherichia coli by laser ray nephelometry
Resano, F.; Trujillo, J.; Cervera, J.E.; Pinzón-Estrada, E.; Landa, L.
Archivos de Investigacion Medica 16(1): 71-79
1985
ISSN/ISBN: 0066-6769 PMID: 3893351 Document Number: 248167
One of the most frequent etiologic agents in the production of diarrhea is enterotoxigenic E. coli, which produces 2 types of toxins, 1 is thermolabile (TLT) and the other is thermostable (TST). Both exert their action by stimulating adenylate cyclase, which produces alterations in the absorption and secretion of electrolytes and water in the intestinal cells. In order to detect the presence of these toxins, tests were devised that present difficulties for their systematic use in a clinical laboratory, such as rabbit blind loop assay, tissue culture, passive hemolysis, etc. A more simple method of application in which a laser beam nephelometer is used is presented. The development of the method included: production of thermolabile antitoxin antiserum in rabbits by means of a known toxigenic strain (H-10407), titration of optimal levels of toxin and antibody and trials for the most convenient times and temperatures for the immunochemical reaction system. The stages are described in detail and the results obtained with the nephelometer are presented. These results are in turn compared with a reference method, namely that of the rabbit blind intestinal loop assay. The method apparently is accessible and more simple than various other methods previously described, and is besides, reliable and reproductible.