John Robin Warren AC ( born 11 June 1937 in Adelaide ) is an Australian pathologist , Nobel winner and researcher . In 1979 , he re-discoved the bacterium Helicobacter pylori , together with Barry Marshall . John Robin Warren AC ( born 11 June 1937 in Adelaide ) is an Australian pathologist , Nobel Laureate and researcher who is credited with the 1979 re-discovery of the bacterium Helicobacter pylori , together with Barry Marshall .