title: DNA sequence analysis of rdxA and frxA from paired metronidazole-sensitive and -resistant Helicobacter pylori isolates obtained from patients with heteroresistance.
abstract: Genomic variations of rdxA and frxA genes in eight pairs of metronidazole (MTZ)-sensitive and -resistant isolates of Helicobacter pylori were investigated. The paired strains from each single biopsy had identical lspA-glmM restriction fragment length polymorphism profiles, and the differences in MTZ susceptibility were mostly accounted for by mutations in the rdxA gene. Truncation of RdxA is associated with a minimum inhibitory concentration of 64-128 mg/L. Early truncation of FrxA was observed both in susceptible and resistant isolates of seven paired strains. Inactivation of frxA might play a significant role only in one low-level MTZ-resistant isolate where a missense mutation was found in the rdxA gene.
authors.affiliation: Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, piso 12, 1121, Buenos Aires, Argentina.
authors.forename: Mario José
authors.initials: MJ
authors.lastname: Matteo
authors.forename: Cecilia Valeria
authors.initials: CV
authors.lastname: Pérez
authors.forename: Mara Roxana
authors.initials: MR
authors.lastname: Domingo
authors.forename: Martín
authors.initials: M
authors.lastname: Olmos
authors.forename: Cristian
authors.initials: C
authors.lastname: Sanchez
authors.forename: Mariana
authors.initials: M
authors.lastname: Catalano
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D016481:Helicobacter Infections / Q000188:drug therapy / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008795:Metronidazole / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009154:Mutation; D009601:Nitroreductases / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D017386:Sequence Homology, Amino Acid
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008795:Metronidazole; D009601:Nitroreductases; C476646:RdxA protein, Helicobacter pylori