The use of Bacillus diarrhoeal enterotoxin (BDE) detection using an ELISA technique in the confirmation of the aetiology of Bacillus-mediated diarrhoea

A commercially available ELISA kit was used for the detection of Bacillus diarrhoeal enterotoxin (BDE) in a variety of foods and faeces. The ability of isolates of Bacillus spp., including Bacillus cereus , to produce BDE in Brain Heart Infusion broth containing 0·1% glucose was also checked by use of the kit. Results show that 29 out of 31 B. cereus isolates were enterotoxigenic. Foods positive for preformed BDE were always contaminated with >10⁵ B. cereus cfu g⁻¹, but not all foods contaminated with large numbers of B. cereus were positive for BDE. Bacillus spp., other than one isolate which closely resembled B. subtilis , were negative for BDE production. Criteria for the confirmation of Bacillus -mediated diarrhoea should now include reports of symptoms and incubation periods consistent with the diarrhoeal form of food-poisoning by Bacillus spp., together with the results of tests for enterotoxigenicity of the Bacillus isolate, and detection of BDE in either the food and/or faeces.