title: Rapid evolution of distinct Helicobacter pylori subpopulations in the Americas.
abstract: For the last 500 years, the Americas have been a melting pot both for genetically diverse humans and for the pathogenic and commensal organisms associated with them. One such organism is the stomach-dwelling bacterium Helicobacter pylori, which is highly prevalent in Latin America where it is a major current public health challenge because of its strong association with gastric cancer. By analyzing the genome sequence of H. pylori isolated in North, Central and South America, we found evidence for admixture between H. pylori of European and African origin throughout the Americas, without substantial input from pre-Columbian (hspAmerind) bacteria. In the US, strains of African and European origin have remained genetically distinct, while in Colombia and Nicaragua, bottlenecks and rampant genetic exchange amongst isolates have led to the formation of national gene pools. We found three outer membrane proteins with atypical levels of Asian ancestry in American strains, as well as alleles that were nearly fixed specifically in South American isolates, suggesting a role for the ethnic makeup of hosts in the colonization of incoming strains. Our results show that new H. pylori subpopulations can rapidly arise, spread and adapt during times of demographic flux, and suggest that differences in transmission ecology between high and low prevalence areas may substantially affect the composition of bacterial populations.
authors.affiliation: Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Kaisa
authors.identifier: 0000-0002-4447-8968
authors.initials: K
authors.lastname: Thorell
authors.affiliation: Dept. of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Koji
authors.identifier: 0000-0003-4289-1115
authors.initials: K
authors.lastname: Yahara
authors.affiliation: Medical Microbiology and Infectious Disease group, Swansea University, Swansea, Wales, United Kingdom.
authors.forename: Elvire
authors.identifier: 0000-0003-4232-9448
authors.initials: E
authors.lastname: Berthenet
authors.affiliation: Integrative Epidemiology Unit, School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom.
authors.forename: Daniel J
authors.identifier: 0000-0002-5311-6213
authors.initials: DJ
authors.lastname: Lawson
authors.affiliation: Medical Microbiology and Infectious Disease group, Swansea University, Swansea, Wales, United Kingdom.
authors.forename: Jane
authors.initials: J
authors.lastname: Mikhail
authors.affiliation: Karmanos Cancer Institute, Wayne State University, Detroit, Michigan, United States of America.
authors.forename: Ikuko
authors.initials: I
authors.lastname: Kato
authors.affiliation: Instituto Politecnico Nacional, ENCB, Mexico City, Mexico.
authors.forename: Alfonso
authors.identifier: 0000-0003-1871-4311
authors.initials: A
authors.lastname: Mendez
authors.affiliation: Dipartimento di Ricerca Traslazionale e Nuove Tecnologie in Medicina e Chirurgia, Universitá di Pisa, Pisa, Italy.
authors.forename: Cosmeri
authors.identifier: 0000-0002-7830-2178
authors.initials: C
authors.lastname: Rizzato
authors.affiliation: Grupo de Investigación en Biología del Cáncer, Instituto Nacional de Cancerología, Bogota, Colombia.
authors.forename: María Mercedes
authors.identifier: 0000-0002-6472-8362
authors.initials: MM
authors.lastname: Bravo
authors.affiliation: Dept. of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Oita, Japan.
authors.forename: Rumiko
authors.initials: R
authors.lastname: Suzuki
authors.affiliation: Dept. of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Oita, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Yamaoka
authors.affiliation: Unidad de Investigación en Enfermedades Infecciosas, UMAE Pediatria, IMSS, Mexico City, Mexico.
authors.forename: Javier
authors.identifier: 0000-0003-3945-4221
authors.initials: J
authors.lastname: Torres
authors.affiliation: Milner Center for Evolution, Dept. of Biology and Biochemistry, University of Bath, Bath, United Kingdom.
authors.forename: Samuel K
authors.initials: SK
authors.lastname: Sheppard
authors.affiliation: Milner Center for Evolution, Dept. of Biology and Biochemistry, University of Bath, Bath, United Kingdom.
authors.forename: Daniel
authors.initials: D
authors.lastname: Falush
mesh_terms: D000483:Alleles; D004272:DNA, Mitochondrial / Q000235:genetics; D019143:Evolution, Molecular; D016680:Genome, Bacterial; D016481:Helicobacter Infections / Q000453:epidemiology / Q000235:genetics*; D016480:Helicobacter pylori / Q000235:genetics* / Q000472:pathogenicity; D006801:Humans; D007198:Indians, North American; D007843:Latin America; D010802:Phylogeny; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000235:genetics* / Q000382:microbiology; D044465:White People
chemical_list: D004272:DNA, Mitochondrial