A simplified method for detecting the heat-labile enterotoxin of Escherichia coli

A tissue-culture method is described that is suitable for screening large numbers of Escherichia coli isolates for heat-labile enterotoxin production. The method uses readily available laboratory media for culture of the E. coli and does not require cell-free extracts. Antibiotics are used to increase toxin production to levels that allow cultures from several different colonies to be pooled for testing, thus minimising the number of tissue-culture monolayers required. Y1 mouse adrenal cells are used in microplate cultures. The method is simple, sensitive and economical and is suitable for use in a routine diagnostic microbiology laboratory.