INHIBITORY ACTIVITY OF GUT BACTERIA AGAINST ESCHERICHIA-COLI O157 MEDIATED BY DIETARY PLANT METABOLITES

Under both aerobic and anaerobic conditions, the growth of Escherichia coli O157 strain NCTC 12900 was inhibited by the coumarins esculetin, umbelliferone and scopoletin, but not by the coumarin glycoside escul in. Esculin-hydrolysing bacteria from the rumen, the pig gut and the h uman gut inhibited growth of E-coli in an overlay-plate assay in the p resence of esculin. The combined effect of esculetin and volatile fatt y acids was greater than the effect of either factor alone suggesting that coumarin glycosides in the diet might reduce the growth or surviv al of E-coli O157 in the gut. Adding esculin to incubations of mixed r umen contents significantly reduced the survival of E-coli O157.