A 500-year tale of co-evolution, adaptation, and virulence: Helicobacter pylori in the Americas.

Helicobacter pylori is a common component of the human stomach microbiota, possibly dating back to the speciation of Homo sapiens. A history of pathogen evolution in allopatry has led to the development of genetically distinct H. pylori subpopulations, associated with different human populations, and more recent admixture among H. pylori subpopulations can provide information about human migrations. However, little is known about the degree to which some H. pylori genes are conserved in the face of admixture, potentially indicating host adaptation, or how virulence genes spread among different populations. We analyzed H. pylori genomes from 14 countries in the Americas, strains from the Iberian Peninsula, and public genomes from Europe, Africa, and Asia, to investigate how admixture varies across different regions and gene families. Whole-genome analyses of 723 H. pylori strains from around the world showed evidence of frequent admixture in the American strains with a complex mosaic of contributions from H. pylori populations originating in the Americas as well as other continents. Despite the complex admixture, distinctive genomic fingerprints were identified for each region, revealing novel American H. pylori subpopulations. A pan-genome Fst analysis showed that variation in virulence genes had the strongest fixation in America, compared with non-American populations, and that much of the variation constituted non-synonymous substitutions in functional domains. Network analyses suggest that these virulence genes have followed unique evolutionary paths in the American populations, spreading into different genetic backgrounds, potentially contributing to the high risk of gastric cancer in the region.

A rare cause of vertebral osteomyelitis: the first case report of rat-bite fever in Portugal

Abstract Rat-bite fever is a rarely diagnosed illness caused by Streptobacillus moniliformis . Although this disease is distributed worldwide, there have been few cases reported in Europe. Here, we report a case of vertebral osteomyelitis and sternoclavicular septic arthritis caused by S. moniliformis in a Portuguese patient previously bitten by a rat. Laboratory diagnosis was performed using molecular identification. This is the first case report of rat-bite fever in Portugal. The case described here serves as a reminder for physicians to consider this diagnosis in patients who have developed fever syndromes after being in contact with rodents.

A rare cause of vertebral osteomyelitis: the first case report of rat-bite fever in Portugal.

Rat-bite fever is a rarely diagnosed illness caused by Streptobacillus moniliformis . Although this disease is distributed worldwide, there have been few cases reported in Europe. Here, we report a case of vertebral osteomyelitis and sternoclavicular septic arthritis caused by S. moniliformis in a Portuguese patient previously bitten by a rat. Laboratory diagnosis was performed using molecular identification. This is the first case report of rat-bite fever in Portugal. The case described here serves as a reminder for physicians to consider this diagnosis in patients who have developed fever syndromes after being in contact with rodents.

Population genetic structure of Helicobacter pylori strains from Portuguese-speaking countries.

BACKGROUND: The human gastric colonizer Helicobacter pylori is useful to track human migrations given the agreement between the bacterium phylogeographic distribution and human migrations. As Portugal was an African and Brazilian colonizer for over 400 years, we hypothesized that Portuguese isolates were likely genetically closer with those from countries colonized by Portuguese in the past. We aimed to characterize the population structure of several Portuguese-speaking countries, including Portugal, Brazil, Angola, and Cape Verde. MATERIALS AND METHODS: We included strains isolated in Portugal from Portuguese and from former Portuguese colonies. These strains were typed by multilocus sequence typing (MLST) for seven housekeeping genes. We also retrieved from Multi Locus Sequence Typing Web site additional housekeeping gene sequences, namely from Angola and Brazil. RESULTS: We provided evidence that strains from Portuguese belong to hpEurope and that the introgression of hpEurope in non-European countries that speak Portuguese is low, except for Brazil and Cape Verde, where hpEurope accounted for one quarter and one half of the population, respectively. We found genetic similarity for all strains from Portuguese-speaking countries that belong to hpEurope population. Moreover, these strains showed a predominance of ancestral Europe 2 (AE2) over ancestral Europe 1 (AE1), followed by ancestral Africa 1. CONCLUSIONS: H. pylori is a useful marker even for relative recent human migration events and may become rapidly differentiated from founder populations. H. pylori from Portuguese-speaking countries assigned to hpEurope appears to be a hybrid population resulting from the admixture of AE1, AE2 and ancestral hpAfrica1.