Bacterial toxins and diarrhoea.

Bacteria and their toxins are responsible for an enormous burden of diarrhoeal disease. Knowledge about the toxins and their mechanisms of action is limited. Thus, although considerable information is available about the mechanism of action of cholera toxin and a small number of heat-stable enterotoxins, information on the role and action of many others is incomplete. The demonstration of a toxic effect in a test system does not necessarily imply that that activity is relevant to the pathogenesis of the diarrhoea. On the other hand, the absence of a toxic effect in experimental systems does not eliminate the possibility that a toxin is responsible for a particular organism's clinical effects. This is a field of active research and much more work is clearly required.