ABSTRACT

It is now recognized that all external body surfaces have a normal resident bacterial flora, and this includes the digestive tract. Because of cell turnover, gut surfaces are coated with dead and desquamating cells, and these provide an excellent basal nutrient source, to which can be added nutrients passing through the lumen of the gut. During the last 25 years there has been a massive increase in our knowledge about the gut flora at different sites in the digestive tract (Drasar and Hill, 1974; Hill and Marsh, 1990). This has occurred as a result of improved anaerobic culture techniques, the recognition of the limitations on the data and attempts to moderate those limitations.