Identification of New Helicobacter pylori Subpopulations in Native Americans and Mestizos From Peru.

Region-specific Helicobacter pylori subpopulations have been identified. It is proposed that the hspAmerind subpopulation is being displaced from the Americans by an hpEurope population following the conquest. Our study aimed to describe the genomes and methylomes of H. pylori isolates from distinct Peruvian communities: 23 strains collected from three groups of Native Americans (Asháninkas [ASHA, n = 9], Shimaas [SHIM, n = 5] from Amazonas, and Punos from the Andean highlands [PUNO, n = 9]) and 9 modern mestizos from Lima (LIM). Closed genomes and DNA modification calls were obtained using SMRT/PacBio sequencing. We performed evolutionary analyses and evaluated genomic/epigenomic differences among strain groups. We also evaluated human genome-wide data from 74 individuals from the selected Native communities (including the 23 H. pylori strains donors) to compare host and bacterial backgrounds. There were varying degrees of hspAmerind ancestry in all strains, ranging from 7% in LIM to 99% in SHIM. We identified three H. pylori subpopulations corresponding to each of the Native groups and a novel hspEuropePeru which evolved in the modern mestizos. The divergence of the indigenous H. pylori strains recapitulated the genetic structure of Native Americans. Phylogenetic profiling showed that Orthogroups in the indigenous strains seem to have evolved differentially toward epigenomic regulation and chromosome maintenance, whereas OGs in the modern mestizo (LIM) seem to have evolved toward virulence and adherence. The prevalence of cagA +/vacA s1i1m1 genotype was similar across populations (p = 0.32): 89% in ASHA, 67% in PUNO, 56% in LIM and 40% in SHIM. Both cagA and vacA sequences showed that LIM strains were genetically differentiated (p < 0.001) as compared to indigenous strains. We identified 642 R-M systems with 39% of the associated genes located in the core genome. We found 692 methylation motifs, including 254 population-specific sequences not previously described. In Peru, hspAmerind is not extinct, with traces found even in a heavily admixed mestizo population. Notably, our study identified three new hspAmerind subpopulations, one per Native group; and a new subpopulation among mestizos that we named hspEuropePeru. This subpopulation seems to have more virulence-related elements than hspAmerind. Purifying selection driven by variable host immune response may have shaped the evolution of Peruvian subpopulations, potentially impacting disease outcomes.

Rapid evolution of the Helicobacter pylori AlpA adhesin in a high gastric cancer risk region from Colombia.

To be able to survive, Helicobacter pylori must adhere to the gastric epithelial cells of its human host. For this purpose, the bacterium employs an array of adhesins, for example, AlpA. The adhesin AlpA has been proposed as a major adhesin because of its critical role in human stomach colonization. Therefore, understanding how AlpA evolved could be important for the development of new diagnostic strategies. However, the genetic variation and microevolutionary patterns of alpA have not been described in Colombia. The study aim was to describe the variation patterns and microevolutionary process of alpA in Colombian clinical isolates of H. pylori. The existing polymorphisms, which are deviations from the neutral model of molecular evolution, and the genetic differentiation of the alpA gene from Colombian clinical isolates of H. pylori were determined. The analysis shows that gene conversion and purifying selection have shaped the evolution of three different variants of alpA in Colombia.

Phylogenomics of Colombian Helicobacter pylori isolates.

BACKGROUND: During the Spanish colonisation of South America, African slaves and Europeans arrived in the continent with their corresponding load of pathogens, including Helicobacter pylori. Colombian strains have been clustered with the hpEurope population and with the hspWestAfrica subpopulation in multilocus sequence typing (MLST) studies. However, ancestry studies have revealed the presence of population components specific to H. pylori in Colombia. The aim of this study was to perform a thorough phylogenomic analysis to describe the evolution of the Colombian urban H. pylori isolates. RESULTS: A total of 115 genomes of H. pylori were sequenced with Illumina technology from H. pylori isolates obtained in Colombia in a region of high risk for gastric cancer. The genomes were assembled, annotated and underwent phylogenomic analysis with 36 reference strains. Additionally, population differentiation analyses were performed for two bacterial genes. The phylogenetic tree revealed clustering of the Colombian strains with hspWestAfrica and hpEurope, along with three clades formed exclusively by Colombian strains, suggesting the presence of independent evolutionary lines for Colombia. Additionally, the nucleotide diversity of horB and vacA genes from Colombian isolates was lower than in the reference strains and showed a significant genetic differentiation supporting the hypothesis of independent clades with recent evolution. CONCLUSIONS: The presence of specific lineages suggest the existence of an hspColombia subtype that emerged from a small and relatively isolated ancestral population that accompanied crossbreeding of human population in Colombia.

Computational analysis of 1,3-propanediol operon transcriptional regulators: insights into Clostridium sp. glycerol metabolism regulation / Análisis computacional de los reguladores transcripcionales del operón 1,3-propanodiol: indicios sobre la regulación del metabolismo del glicerol en Clostridium sp / Análise computacional dos reguladores transcricionais do operon do 1,3-Propanodiol: Panorama da regulacáo do metabolismo do glicerol no Clostridium sp

We designed a strategy for the sequencing and bioinformatical characterization of the 1,3-propanediol operon regulator genes from the Colombian Clostridium sp. strain IBUN13A, which is taxonomically related to Clostridium butyricum. Three genes are proposed to be involved in the operon's transcriptional activity, the dhaS and dhaA genes through a two-component system and the third gene named dhaY, which encodes a putative transcriptional regulator similar to the domains of the dhaS/A system. Phylogenetic analyses indicated that the predicted proteins had a modular structure consisting of domains homologous to different signal transduction systems, but had significant differences concerning their conserved residues, pointing to the possibility that they constitute ancestral domains. In accordance with the prediction of functions, we propose a mechanism of regulation of the proteins studied of the 1,3-propanediol operon of the native strain, as a response to the presence of glycerol in the medium, which provides valuable information on the overall regulation of the glycerol metabolism in Clostridium sp.

Se diseñó una estrategia de amplificación, secuenciación y caracterización bioinformática de los genes reguladores del operón 1,3-propanediol (1,3-PD) de la cepa nativa colombiana Clostridium sp. IBUN 13A, relacionada taxonómicamente con Clostridium butyricum. Se identificaron tres genes que pueden estar involucrados en la regulación transcripcional de dicho operón: los genes dhaS y dhaA -a través de un sistema de transducción de señales de dos componentes-y un tercer gen que se denominó dhaY, que codifica para un regulador transcripcional putativo, similar a los dominios presentes en las proteínas del sistema DhaS/A. Los análisis filogenéticos indican que las proteínas predichas presentan una estructura modular con dominios homólogos a diferentes sistemas de transducción de señales, pero muestran diferencias importantes en los residuos conservados, lo que sugiere que podrían ser estos los dominios ancestrales. La predicción de funciones postula un mecanismo de regulación de las proteínas estudiadas sobre el promotor del operón 1,3-PD de la cepa nativa como respuesta a la presencia de glicerol en el medio, lo cual aporta información importante sobre la regulación global del metabolismo del glicerol en Clostridium sp.

Nesta pesquisa foi feita uma estratégia para a amplificacäo, sequenciamento e caracterizacäo bioinformática dos genes reguladores do operon 1,3 propanodiol (1,3-PD) da cepa colombiana Clostridium sp. IBUN 13A, relacionada taxonomicamente com o Clostridium butyricum. Tèm sido identificados tres genes que podem estar envolvidos na regulacáo transcricional do operon. Os genes dhaS e dhaA por meio de um sistema de dois componentes e o terceiro gene nomeado de dhaY, que codifica para um regulador transcridonal putativo, parecido com os dominios presentes nas proteínas do sistema DhaS/A. A análise filogenètica mostra que estas proteínas apresentam uma estrutura modular com dominios homólogos a diferentes sistemas de traducáo de sinais, mas pressupöem diferencas importantes nos residuos conservados, indicando provavelmente que possam constituir os dominios ancestrais. De acordo com a predicáo de funcöes, é postulado um mecanismo de regulacáo do sistema DhaS/A, DhaY sobre o promotor do operon 1,3-DP da cepa nativa, como resposta à presenca de glicerol no meio, aportando informacöes importantes da regulacáo global do metabolismo do glicerol no Clostridium sp.

Metagenomic analysis of the gastric microbiota cultivable from a patient with gastritis concomitant with Barrett's esophagus.

Barrett's esophagus is a distal metaplasia characterized by the transformation of squamous mucosa into columnar mucosa. This esophageal phenotype is a product not only of the chronic reflux of gastric acids, but also by microorganisms that colonize the oral cavity and stomach. Two classes of microbiota can be identified in Barrett's esophagus; microbiota type I is associated with the normal esophagus and type II with an inflamed esophagus. The present study describes the gastric microbiota of a patient with antral gastritis concomitant with Barrett's esophagus absent infection with Helicobacter pylori. Gastric biopsies were obtained following the protocol of Sydney and following ethical practices. The isolates were cultivated under microaerophilic conditions on Columbia Agar supplemented with IsoVitaleX™ and 7% sterile blood. Extracted DNA was sequenced using 454-GS and the results analyzed on the MG-RAST server. Gram negative isolates were found and bacteria resistant to levofloxacin, amoxicillin, tetracycline, erythromycin, and clarithromycin. The phyla Bacteroidetes, Firmicutes, Fusobacteria and Proteobacteria, the genus Bacteroides and the species group Bacteroides fragilis were most abundant. Functionally, the metabolism of carbohydrates, amino acids, and to a lesser extent, the metabolism of cofactors and vitamins were most dominant, and of which the enzymes ß-glucosidase (EC 3.2.1.21), ß-galactosidase (EC 3.2.1.23) and ß-N-acetylhexosaminidase (EC 3.2.1.52) were most dominant. The findings of this study, because they are of only one case may probably suggest a possible pathogenic role, previously undescribed for Bacteroides fragilis, associated with human gastritis when concomitant esophageal pathology exists.

Metagenomic analysis of the gastric microbiota cultivable from a patient with gastritis concomitant with Barrett´s esophagus / Análisis metagenómico de la microbiota gástrica cultivable a partir de un paciente con gastritis concomitante con esófago de Barrett

Barrett’s esophagus is a distal metaplasia characterized by the transformation of squamous mucosa into columnar mucosa. This esophageal phenotype is a product not only of the chronic reflux of gastric acids, but also by microorganisms that colonize the oral cavity and stomach. Two classes of microbiota can be identified in Barrett’s esophagus; microbiota type I is associated with the normal esophagus and type II with an inflamed esophagus. The present study describes the gastric microbiota of a patient with antral gastritis concomitant with Barrett’s esophagus absent infection with Helicobacter pylori. Gastric biopsies were obtained following the protocol of Sydney and following ethical practices. The isolates were cultivated under microaerophilic conditions on Columbia Agar supplemented with IsoVitaleX™ and 7% sterile blood. Extracted DNA was sequenced using 454-GS and the results analyzed on the MG-RAST server. Gram negative isolates were found and bacteria resistant to levofloxacin, amoxicillin, tetracycline, erythromycin, and clarithromycin. The phyla Bacteroidetes, Firmicutes, Fusobacteria and Proteobacteria, the genus Bacteroides and the species group Bacteroides fragilis were most abundant. Functionally, the metabolism of carbohydrates, amino acids, and to a lesser extent, the metabolism of cofactors and vitamins were most dominant, and of which the enzymes β-glucosidase (EC 3.2.1.21), β-galactosidase (EC 3.2.1.23) and β-N-acetylhexosaminidase (EC 3.2.1.52) were most dominant. The findings of this study, because they are of only one case may probably suggest a possible pathogenic role, previously undescribed for Bacteroides fragilis, associated with human gastritis when concomitant esophageal pathology exists.

El esófago de Barrett es una metaplasia distal caracterizada por la transformación de la mucosa escamosa a mucosa columnar. Este fenotipo esofágico es producto no solo de la exposición crónica al reflujo de ácidos gástricos sino también a microbios colonizantes de la cavidad oral y del estómago. El esófago Barrett presenta 2 clases de microbiotas; la microbiota tipo I asociada con esófago normal y la tipo II a fenotipos esofágicos inflamatorios. En el presente estudio se describió la microbiota gástrica de una paciente con gastritis antral concomitante con esófago de Barrett sin infección por Helicobacter pylori y se obtuvieron biopsias gástricas siguiendo el protocolo de Sydney y estándares bioéticos. Los cultivos se hicieron en condiciones microaerofílicas en agar Columbia suplementados con isovitalex y sangre estéril al 7%. El ADN extraído fue sometido a secuenciación empleando 454 GS y las lecturas fueron analizadas en el servidor MG-RAST. Se obtuvieron aislamientos gram-negativos y resistentes a levofloxacina, amoxicilina, tetraciclina, eritromicina y claritromicina. Los Phylum Bacteroidetes, Firmicutes, Fusobacteria y Proteobacteria, el género Bacteroides y las especies de grupo Bacteroides fragilis fueron los más abundantes. Funcionalmente, el metabolismo de carbohidratos, aminoácidos y en menor grado el metabolismo de cofactores y vitaminas fueron los más dominantes; de los cuales las enzimas la β-glicosidasa (EC 3.2.1.21), β-galactosidasa (EC 3.2.1.23) y la β-N-acetilhexosaminidasa (EC 3.2.1.52) fueron las más dominantes. Estos resultados, por ser de un solo caso, solo podrían sugerir un posible papel patogénico no descrito para Bacterioides fragilis asociado con gastritis humana cuando existe patología esofágica concomitante.