title: Diversification of thevacAs1m1andvacAs2m2Strains ofHelicobacter pyloriinMeriones unguiculatus.
abstract: The bacteriumHelicobacter pyloriexhibits great genetic diversity, and the pathogenic roles of its virulence factors have been widely studied. However, the evolutionary dynamics ofH. pyloristrains during stomach colonization are not well-characterized. Here, we analyzed the microevolutionary dynamics of the toxigenic strainvacAs1m1, the non-toxigenic strainvacAs2m2, and a combination of both strains in an animal model over time.Meriones unguiculatuswere inoculated with the following bacteria: group 1-toxigenic strainvacAs1m1/cagA+/cagE+/babA2+; ST181, group 2-non-toxigenic strainvacAs2m2/cagA+/cagE+/babA2+; ST2901, and group 3-both strains. The gerbils were euthanized at different time points (3, 6, 12, and 18 months). In group 1, genetic alterations were observed at 6 and 12 months. With the combination of both strains, group 3 also exhibited genetic alterations at 3 and 18 months; moreover, a chimera,vacA m1-m2, was detected. Additionally, four new sequence types (STs) were reported in the PubMLST database forH. pylori. Synonymous and non-synonymous mutations were analyzed and associated with alterations in amino acids. Microevolutionary analysis of the STs (PHYLOViZ) identified in each group revealed many mutational changes in the toxigenic (vacAs1m1) and non-toxigenic (vacAs2m2) strains. Phylogenetic assessments (eBURST) did not reveal clonal complexes. Our findings indicate that the toxigenic strain,vacAs1m1, and a combination of toxigenic and non-toxigenic strains acquired genetic material by recombination. The allelic combination,vacAs2m1, displayed the best adaptation in the animal model over time, and a chimera,m1-m2, was also identified, which confirmed previous reports.
authors.affiliation: Laboratorio de Infectología, Departamento de Infectologia, Hospital Infantil de México Federico GómezCiudad de México, Mexico; Posgrado en Ciencias Químicobiológicas, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico NacionalCiudad de México, Mexico; Laboratorio de Variación Biológica y Evolución, Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico NacionalCiudad de México, Mexico.
authors.forename: Sandra
authors.initials: S
authors.lastname: Mendoza-Elizalde
authors.affiliation: Laboratorio de Infectología, Departamento de Infectologia, Hospital Infantil de México Federico GómezCiudad de México, Mexico; Posgrado en Ciencias en Biomedicina y Biotecnología Molecular, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico NacionalCiudad de México, Mexico.
authors.forename: Nancy K
authors.initials: NK
authors.lastname: Arteaga-Resendiz
authors.affiliation: Dirección de Planeación, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico.
authors.forename: Pedro
authors.initials: P
authors.lastname: Valencia-Mayoral
authors.affiliation: Bioterio, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico.
authors.forename: Raúl C
authors.initials: RC
authors.lastname: Luna
authors.affiliation: Laboratorio de Infectología, Departamento de Infectologia, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico.
authors.forename: Sarbelio
authors.initials: S
authors.lastname: Moreno-Espinosa
authors.affiliation: Laboratorio de Investigación en Patología Experimental, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico.
authors.forename: Francisco
authors.initials: F
authors.lastname: Arenas-Huertero
authors.affiliation: Laboratorio de Variación Biológica y Evolución, Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional Ciudad de México, Mexico.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Zúñiga
authors.affiliation: Laboratorio de Infectología, Departamento de Infectologia, Hospital Infantil de México Federico Gómez Ciudad de México, Mexico.
authors.forename: Norma
authors.initials: N
authors.lastname: Velázquez-Guadarrama
keywords: H. pylori; Meriones unguiculatus; PHYLOViZ; animal model; diversification of genotypes; eBURST; natural chimera