Helicobacter pylori oipA, vacA and dupA genetic diversity in individual hosts

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’.

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DNA sequence analysis of rdxA and frxA from paired metronidazole-sensitive and -resistant Helicobacter pylori isolates obtained from patients with heteroresistance

International Journal of Antimicrobial Agents ◽

10.1016/j.ijantimicag.2005.09.019 ◽

2006 ◽

Vol 27 (2) ◽

pp. 152-158 ◽

Cited By ~ 13

Author(s):

Mario José Matteo ◽

Cecilia Valeria Pérez ◽

Mara Roxana Domingo ◽

Martín Olmos ◽

Cristian Sanchez ◽

...

Keyword(s):

Helicobacter Pylori ◽

Sequence Analysis ◽

Dna Sequence ◽

Dna Sequence Analysis

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Helicobacter pylori cag pathogenicity island genotype diversity within the gastric niche of a single host

Journal of Medical Microbiology ◽

10.1099/jmm.0.46885-0 ◽

2007 ◽

Vol 56 (5) ◽

pp. 664-669 ◽

Cited By ~ 28

Author(s):

Mario José Matteo ◽

Gabriela Granados ◽

Cecilia Valeria Pérez ◽

Martín Olmos ◽

Cristian Sanchez ◽

...

Keyword(s):

Helicobacter Pylori ◽

Clinical Presentation ◽

Random Amplified Polymorphic Dna ◽

Positive Culture ◽

Pathogenicity Island ◽

Empty Site ◽

Multiple Biopsies ◽

Single Host ◽

Dna Pcr ◽

Positive Half

cag pathogenicity island (PAI) integrity was investigated in isolates from multiple biopsies recovered from 40 patients in an attempt to determine the co-existence of a varying cagPAI-positive to cagPAI-negative ratio in a single host. Six biopsies were obtained from each patient during the same endoscopic session. cagPAI analysis included amplification of seven loci (cagA, cagE, cagG, cagM, cagT, HP0527 and HP0524) and the left end of cagII (LEC). Absence of the island was confirmed by empty-site PCR. lspA-glmM RFLP and random amplified polymorphic DNA PCR were used for strain delineation. The number of biopsies with Helicobacter pylori-positive culture ranged from three to six per patient and a total of 218 isolates were recovered. Mixed infection was only found in two patients. Nearly one-third of the 40 patients harboured isolates with an intact cagPAI in all niches, another third of the isolates were empty-site-positive in all niches, whilst the remaining third of the isolates had a disrupted cagPAI in all or at least one of the niches. Co-existence of variants of the same strain with different cagPAI genotypes was observed in one-quarter of patients. The variations in cagPAI genotype included co-existence of: diverse cagPAI deletions in different niches, variants with intact and with partially deleted islands, variants with empty-site-positive and with partially deleted cagPAIs, and variants with an intact cagPAI and with empty-site-positive. Half of the patients with different cagPAI genotypes harboured an intact cagPAI in at least one niche. Co-existence of diverse genotypes of putative virulence factors in a single host must be considered when drawing a correlation with clinical presentation.

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Development of a Tetracycline-Inducible Gene Expression System for the Study of Helicobacter pylori Pathogenesis

Applied and Environmental Microbiology ◽

10.1128/aem.02701-13 ◽

2013 ◽

Vol 79 (23) ◽

pp. 7351-7359 ◽

Cited By ~ 8

Author(s):

Aleksandra W. Debowski ◽

Phebe Verbrugghe ◽

Miriam Sehnal ◽

Barry James Marshall ◽

Mohammed Benghezal

Keyword(s):

Helicobacter Pylori ◽

Animal Models ◽

Chronic Infection ◽

Fluorescent Protein ◽

Expression System ◽

Content Type ◽

Conditional Expression ◽

H Pylori ◽

Green Fluorescent

ABSTRACTDeletion mutants and animal models have been instrumental in the study ofHelicobacter pyloripathogenesis. Conditional mutants, however, would enable the study of the temporal gene requirement duringH. pyloricolonization and chronic infection. To achieve this goal, we adapted theEscherichia coliTn10-derived tetracycline-inducible expression system for use inH. pylori. TheureApromoter was modified by inserting one or twotetoperators to generate tetracycline-responsive promoters, nameduPtetO, and these promoters were then fused to the reportergfpmut2 and inserted into different loci. The expression of the tetracycline repressor (tetR) was placed under the control of one of three promoters and inserted into the chromosome. Conditional expression of green fluorescent protein (GFP) in strains harboringtetRanduPtetO-GFPwas characterized by measuring GFP activity and by immunoblotting. The twotet-responsiveuPtetOpromoters differ in strength, and induction of these promoters was inducer concentration and time dependent, with maximum expression achieved after induction for 8 to 16 h. Furthermore, the chromosomal location of theuPtetO-GFPconstruct and the nature of the promoter driving expression oftetRinfluenced the strength of theuPtetOpromoters upon induction. Integration ofuPtetO-GFPandtetRconstructs at different genomic loci was stablein vivoand did not affect colonization. Finally, we demonstrate tetracycline-dependent induction of GFP expressionin vivoduring chronic infection. These results open new experimental avenues for dissectingH. pyloripathogenesis using animal models and for testing the roles of specific genes in colonization of, adaptation to, and persistence in the host.

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