Volume 91, Issue 5, May (2004), pp. 749-755 © The Author 2004
doi:10.1079/BJN20041101

Medline/PubMed Citation | Related Articles in PubMed | Download to Citation Matcher  

Effects of esculin and esculetin on the survival of Escherichia coli O157 in human faecal slurries, continuous-flow simulations of the rumen and colon and in calves

Sylvia H. Duncan¹, E. Carol McWilliam Leitch¹, Karen N. Stanley¹, Anthony J. Richardson¹, Richard A. Laven², Harry J. Flint¹ and Colin S. Stewart^1
1Gut Microbiology and Immunology Division, Rowett Research Institute, Bucksburn, Aberdeen, AB21 9SB, UK
²Scottish Agricultural College, St Mary's Industrial Estate, Dumfries DG1 1DX, UK

 (Received 21 May 2003–Revised 1 December 2003–Accepted 16 January 2004)

The human pathogen Escherichia coli O157:H7 is thought to be spread by direct or indirect contact with infected animal or human faeces. The present study investigated the effects of the plant coumarin esculin and its aglycone esculetin on the survival of a strain of E. coli O157 under gut conditions. The addition of these compounds to human faecal slurries and in vitro continuous-flow fermenter models simulating conditions in the human colon and rumen caused marked decreases in the survival of an introduced strain of E. coli O157. When four calves were experimentally infected with E. coli O157 and fed esculin, the pathogen was detected in five of twenty-eight (18%) of faecal samples examined post-inoculation, compared with thirteen of thirty-five (37%) of faecal samples examined from five control calves not fed esculin. Coumarin compounds that occur naturally in dietary plants or when supplemented in the diet probably inhibit the survival of E. coli O157 in the gut.

Keywords:
Plant coumarins, Escherichia coli O157, Rumen, Colon

Abbreviations:
APB, anaerobic phosphate buffer, cfu, colony-forming units, DMSO, dimethyl sulfoxide, LB, Luria Bertani