The Effect of Gut Environmental Conditions on the Survival of Human Pathogenic Bacteria in the GI Tract of Farm Animals.

Escherichia coli O157 is a notorious human pathogen that produces toxins that cause damage to the kidneys and brain. This bacterium may be shed in the faeces of farm animals. The potential for using dietary changes to reduce shedding have been investigated, through studies on the mechanisms by which certain plant compounds and acids produced by fermentation inhibit the growth and survival of this pathogen. <P> Parameters studied include effects on survival, the maintenance of internal pH and transmembrane potentials and the expression of cell proteins. Links with ongoing related work funded by DEFRA and Scottish Enterprise will allow the possible commercial application of the findings to be investigated. <P>The work funded by SE will specifically investigate possible application of the findings to other systems such as food processing. <P>The potential for the emergence of new pathogenic bacteria in the gut of farm animals has been studied. This might occur by the transfer of toxin-producing ability from E. coli O157 to other strains of E. coli. The toxin-encoding genes are borne on bacterial viruses (bacteriophages). Joint investigations in vitro carried out with the University of Liverpool sought to identify the factors which affect the survival of these bacteriophages in gut contents and thus to allow estimation of the risks which may exist.