Application of Biken test (modified Elek test) for sampling of heat-stable enterotoxin of Escherichia coli isolated in Bangladesh.

The usefulness of Biken Agar 2 as a source of heat-stable toxin for the suckling mouse assay was examined. Escherichia coli (E. coli) strains isolated in Bangladesh from patients with gastroenteritis found to produce heat-stable toxin (n = 152), both heat-stable and heat-labile toxin (n = 60) and not to produce heat-stable or heat-labile toxin (n = 25) by standard suckling mice assay using broth culture were tested. Sampling from Biken Agar 2 gave comparable results to those obtained using standard broth cultures. This is the first field survey of evaluation of the Biken test for sampling heat-stable toxin of E. coli. The result further clarifies the applicability of the Biken test for sampling heat-stable toxin, and the usefulness of the Biken test for detections of heat-labile and heat-stable toxin produced by E. coli.