title: Helicobacter pylori oipA, vacA and dupA genetic diversity in individual hosts.
abstract: Helicobacter pylori putative virulence factors can undergo a continuously evolving mechanism as an approach to bacterial adaptation to the host changing environment during chronic infection. oipA, vacA and dupA genetic diversity among isolates from multiple biopsies (niches) from the antrum and corpus of 40 patients was investigated. A set of 229 isolates was examined. Direct DNA sequence analysis of amplified fragments was used to study oipA 'on/off' expression status as well as the presence of C or T insertion in jhp0917 that originates a continuous (jhp0917-jhp0918) dupA gene. vacA alleles were identified by multiplex PCR. Different inter-niches oipA CT repeat patterns were observed in nine patients; in six of these, 'on' and 'off' mixed patterns were found. In three of these nine patients, different vacA alleles were also observed in a single host. Inter-niche dupA differences involved the absence and presence of jhp0917 and/or jhp0918 or mutations in dupA, including those that may originate a non-functional gene, and they were also present in two patients with mixed oipA CT patterns and in another seven patients. Evidence of mixed infection was observed in two patients only. In conclusion, oipA and dupA genes showed similar inter-niche variability, occurring in approximately 1/4 patients. Conversely, vacA allele microevolution seemed to be a less common event, occurring in approximately 1/10 patients, probably due to the mechanism that this gene evolves 'in vivo'.
authors: Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors: Mario José
authors: MJ
authors: Matteo
authors: Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors: Rita Inés
authors: RI
authors: Armitano
authors: Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors: Gabriela
authors: G
authors: Granados
authors: Servicio de Gastroenterología, Hospital Escuela 'Don José de San Martín' Facultad de Medicina, Buenos Aires, Argentina.
authors: Andrés Dario
authors: AD
authors: Wonaga
authors: Servicio de Gastroenterología, Hospital Escuela 'Don José de San Martín' Facultad de Medicina, Buenos Aires, Argentina.
authors: Christian
authors: C
authors: Sánches
authors: Servicio de Endoscopía, Hospital General de Agudos Juan A. Fernández, Buenos Aires, Argentina.
authors: Martín
authors: M
authors: Olmos
authors: Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors: Mariana
authors: M
authors: Catalano
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D004381:Duodenal Ulcer / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C528428:DupA protein, Helicobacter pylori; C526444:OipA protein, Helicobacter pylori; C074689:VacA protein, Helicobacter pylori; D037521:Virulence Factors