Production of Escherichia coli group I-like heat-labile enterotoxin by Enterobacteriaceae isolated from environmental water.

Strains of Klebsiella oxytoca (2), Citrobacter freundii (2), Enterobacter cloacae (1) and Escherichia coli (1) isolated from environmental water were identified as heat-labile enterotoxin (LT) producing strains by immunological methods and polymerase chain amplification. A 322 bp amplified fragment was obtained with specific primers LTR and LTL, and hybridized to a digoxigenin-labelled LTB probe only under low stringency conditions, and not with a cholera toxin probe. These results suggest that Enterobacteriaceae may produce a LT-like toxin antigenically and genetically related to the LT enterotoxin of E. coli.