title: Transposition and homologous recombination drive evolution of pUO-StVR2, a multidrug resistance derivative of pSLT, the virulence plasmid specific of Salmonella enterica serovar Typhimurium.
abstract: Five variants of a resistant derivative of pSLT (termed pUO-StVR2) were detected in clinical isolates of Salmonella enterica serovar Typhimurium recovered in Spain. The structure of these variants revealed the involvement of IS1, IS26 and Tn21-like transposition, as well as homologous recombination in the generation of deletions, inversions and insertions which, depending on the variant, affected an orf of unknown function, genes encoding a possible iron acquisition system, and/or resistance properties. These variants, which appeared at a relatively low frequency, can be used as a model to understand the co-selection mechanisms that are helping to maintain multidrug resistance in bacterial pathogens, despite the structural instability of the responsible DNA.
authors.affiliation: Departamento de Biología Funcional (Área de Microbiología), Universidad de Oviedo, Oviedo, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Herrero-Fresno
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Oviedo, Spain.
authors.forename: Rosaura
authors.initials: R
authors.lastname: Rodicio
authors.affiliation: Departamento de Biología Funcional (Área de Microbiología), Universidad de Oviedo, Oviedo, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Montero
authors.affiliation: Departamento de Biología Funcional (Área de Microbiología), Universidad de Oviedo, Oviedo, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: García
authors.affiliation: Departamento de Biología Funcional (Área de Microbiología), Universidad de Oviedo, Oviedo, Spain. Electronic address: rrodicio@uniovi.es.
authors.forename: M Rosario
authors.initials: MR
authors.lastname: Rodicio
mesh_terms: D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics*; D024901:Drug Resistance, Multiple, Bacterial; D019143:Evolution, Molecular; D059765:Homologous Recombination; D010957:Plasmids / Q000235:genetics*; D012486:Salmonella typhimurium / Q000235:genetics* / Q000472:pathogenicity*; D017422:Sequence Analysis, DNA
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial
keywords: Class 1 integron; Complex integron; Insertion sequence; Iron acquisition; Multidrug resistance; Transposon