Ethnic and Geographic Differentiation of Helicobacter pylori within Iran

Saeid Latifi-Navid,Bodo Linz,Azita Ganji,Sebastian Suerbaum,Koroush Ghanadi,Sadegh Massarrat,Seyed Ali Ghorashi,Ali Akbar Shayesteh,Mohsen Masoodi,Tanya Khegay,Reza Malekzadeh,Farideh Siavoshi,Mark Achtman,Daniel Falush,Ali-Hatef Salmanian,Niyaz Ahmed

doi:10.1371/journal.pone.0009645

Abstract

The bacterium Helicobacter pylori colonizes the human stomach, with individual infections persisting for decades. The spread of the bacterium has been shown to reflect both ancient and recent human migrations. We have sequenced housekeeping genes from H. pylori isolated from 147 Iranians with well-characterized geographical and ethnic origins sampled throughout Iran and compared them with sequences from strains from other locations. H. pylori from Iran are similar to others isolated from Western Eurasia and can be placed in the previously described HpEurope population. Despite the location of Iran at the crossroads of Eurasia, we found no evidence that the region been a major source of ancestry for strains across the continent. On a smaller scale, we found genetic affinities between the H. pylori isolated from particular Iranian populations and strains from Turks, Uzbeks, Palestinians and Israelis, reflecting documented historical contacts over the past two thousand years.

Highlights

Helicobacter pylori, a major pathogen of the gastrointestinal tract, has been implicated in a wide spectrum of gastric disorders such as peptic and duodenal ulcerations as well as gastric cancer [1]
Genetic diversity within H. pylori populations tends to decrease with increasing distance from Africa, consistent with a similar but stronger cline observed in humans [4,7,8]
We studied the genetic structure of the populations by analyses of molecular variance (AMOVA) and pair-wise FST using the software package Arlequin 3.1 [21]

Summary

Introduction

Helicobacter pylori, a major pathogen of the gastrointestinal tract, has been implicated in a wide spectrum of gastric disorders such as peptic and duodenal ulcerations as well as gastric cancer [1]. In order to investigate these questions, we have sequenced H. pylori taken from Iranians with well-defined geographical and ethnic origin. It has been estimated that 69% of the Iranian population currently harbour H. pylori infection [14] and show the frequent rate of development of duodenal ulcer [15] and gastric cancer [16], largely influenced by geographic and/or ethnic origin.

Results

Conclusion