DORMANT PHAGES OF HELICOBACTER PYLORI REVEAL DISTINCT POPULATIONS IN EUROPE

Tsachi Tsadok Perets ¹ Filipa Vale ² Jamuna Vadivelu ³ Monica Oleastro ⁴ Sébastien Breurec ⁵ Lars Engstrand ⁶ Francis Megraud ² Philippe Lehours ²

¹Gastroenterology Laboratory, Rabin Medical Center, Petah Tikva, Israel
²Laboratoire de Bactériologie, Université de Bordeaux, Bordeaux, France
³UM Marshall Center and Dept of Medical Microbiology, University of Malaya, Kuala Lumpur, Malaysia
⁴Laboratório Nacional de Referência das Infeções Gastrintestinais, Instituto Nacional de Saúde Dr Ricardo Jorge, Lisboa, Portugal
⁵Labaratoire de Bacteriologie, Institut Pasteur, Dakar, Senegal
⁶Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden

Prophages of Helicobacter pylori, a bacterium known to co-evolve in the stomach of its human host, were recently identified. However, their role in the diversity of H. pylori strains is unknown.
We demonstrate here and for the first time that the diversity of the prophage genes offers the ability to distinguish between European populations, and that H. pylori prophages and their host bacteria share have a complex evolutionary history. By comparing the phylogenetic trees of two prophage genes (integrase and holin) and the multilocus sequence typing (MLST)-based data obtained for seven housekeeping genes, we observed that the majority of the strains belong to
the same phylogeographic group in both trees. Furthermore, we found that the Bayesian analysis of the population structure of the prophage genes identified two H. pylori European populations, hpNEurope and hpSWEurope, while the MLST sequences identified one European population, hpEurope. The population structure analysis of H. pylori prophages was even more discriminative than the traditional MLST-based method for the European population. Prophages are new players
to be considered not only to show the diversity of H. pylori strains but also to more sharply define human populations.