History ofHelicobacter pyloriand Human: An Intimate Story of Pathogen–Host Relationship

Abstract

The history of Helicobacter pylori is a fascinating story from its discovery which changed the paradigm of gastric as a sterile environment and the gastroduodenal diseases to the fact that it is now infecting about half of the human population. Besides the interesting medical aspect, H. pylori also had a unique feature as high recombination and mutation rate, yet exceptionally well‐structured population genetics. In addition, evolutionary relationship with the host had been started at least ∼100 000 years ago and accompanied human migration from Africa to the Pacific. Recent discovery of ‘The Iceman’ H. pylori suggested the second introduction of the bacterium in Europe, which is at least ∼5 300 years old. Tracing of the human– H. pylori association within the past 500 years after colonial expansion showed that H. pylori had more dynamic recombination than its host, yet maintained similarity to its host, suggesting a very intimate relationship between the host and its pathogen. Key Concepts The history of Helicobacter pylori is a fascinating story from its discovery which changed the paradigm of gastric as a sterile environment and the gastroduodenal diseases to the fact that it is now infecting about half of the human population. H. pylori had a unique feature as high recombination and mutation rate, yet exceptionally well‐structured population genetics. Evolutionary relationship with the host had been started at least ∼100 000 years ago and accompanied human migration from Africa to the Pacific. With the increasing number of genomes available for H. pylori , finer resolution human–pathogen relationship could be traced in the past 500 years after the colonial expansion. H. pylori had more dynamic recombination than its host, yet maintained similarity to its host, suggesting a very intimate relationship between the host and its pathogen.