HELICOBACTER-PYLORI IN PEPTIC-ULCER - HAVE KOCH POSTULATES BEEN FULFILLED

This brief review considers whether or not Koch's postulates have been fulfilled for Helicobacter pylori and peptic ulceration. The histolog ical features of peptic ulcer disease in man are active chronic gastri tis with antral predominance, duodenal gastric metaplasia and active d uodenitis. Other features are hyperpepsinogenaemia, relative postprand ial hypergastrinaemia and basal acid hypersecretion. The macroscopic f eatures are duodenal bulb ulceration or lesser curve and antral gastri c ulceration, At present, gastric colonization with H. pylori has been produced in small animal species (rats and mice), but the infection i s difficult to establish in immunocompetent animals, and histological gastritis is unconvincing, In larger animals the germ-free pig has bee n the most reliable model but the gastritis tends to be chronic with l ittle activity. The best examples of acute infection are in three 'sel f-administration' experiments in humans, In these cases acute gastriti s with hypochlorhydria developed which, when it be asymptomatic. Eithe r the circumstances were incompatible with ulceration, or the experime nts were not continued for the many years necessary to develop peptic ulceration, It is concluded that only one of the many steps required f or the development of peptic ulceration has so far been fulfilled, i.e , the ability of H. pylori to produce histological gastritis in a susc eptible host.