DNA patterns of Helicobacter pylori isolated from gastric antrum, body, and suodenum

Prewett, E. J.; Bickley, J.; Owen, Robert J.; Pounder, R. E.

doi:10.1016/0016-5085(92)90165-u

Cited by 87 publications

(51 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…RAPD fingerprints were compared on the basis of criteria adopted by other authors (12,32,36). We considered fingerprints that were different in only one band to be highly similar; variations in band intensity were not taken into account.…”

Section: Methodsmentioning

confidence: 99%

Heterogeneity of cag Genotypes in Helicobacter pylori Isolates from Human Biopsy Specimens

Tomasini¹,

Zanussi²,

Sozzi

et al. 2003

J Clin Microbiol

View full text Add to dashboard Cite

The Helicobacter pylori chromosomal cluster of genes known as the cytotoxin-associated gene (cag) island may have different compositions in infecting strains. In this study, we analyzed 150 single colonies obtained from gastric biopsy specimens from 10 patients infected with cagA-positive H. pylori strains and sweep isolates (isolates harvested with sweep in different points of the plate) from 6 patients infected with cagA-negative strains. Three loci in the cag island (cagA, cagE, and virB11) and the conserved gene glmM (ureC) were investigated by PCR. The levels of anti-H. pylori and anti-CagA antibodies in patient sera were also measured. For subjects infected with cagA-negative strains, all sweep isolates were also negative for cagE and virB11, suggesting the complete absence of the cag island. For subjects infected with cagA-positive strains, most of the isolates were positive for all three genes studied, whereas 24.7% of the isolates had a partial or total deletion of the cag island. cagA, cagE, and virB11 were, respectively, present in 87.3, 77.3, and 90% of the colonies. The deletion of virB11 was always associated with the deletion of cagA and/or cagE. H. pylori colonies with different cag genotypes were isolated within a single gastric biopsy specimen from 3 of the 10 patients and were further characterized by random amplified polymorphic DNA (RAPD) analysis and by sequencing of an arbitrarily selected gene segment. Although the colonies had different cag genotypes, their RAPD profiles were highly similar within each patient, and the nucleotide sequences of the selected gene segment were identical. All of the patients had detectable antibodies against H. pylori, and 9 of 10 had anti-CagA antibodies. In conclusion, we show that a single infecting H. pylori strain may include variable proportions of colony subtypes with different cag genotypes. The extension of our analysis to patients with well-characterized gastric diseases may provide significant information on the relationship between cag genotypes and clinical outcomes of H. pylori infections.Helicobacter pylori is a gram-negative spiral bacterium that colonizes the human stomach. Infection with H. pylori is associated with chronic gastritis, peptic ulcer, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma (25).Although the pathogenesis of H. pylori infection is not completely understood, several putative virulence factors may contribute to mucosal damage (5, 26). The cytotoxin-associated gene (cag) island, an approximately 40-kb cluster of genes in the H. pylori chromosome, probably was inherited by horizontal transfer from an unknown microorganism. Many of the cag genes have homology to those of other bacteria encoding virulence factors and a type IV secretion system. Therefore, they may play an important role in microbial virulence and pathogenicity (6, 10). Among H. pylori isolates, the presence of insertion elements causes differences in the compositions of the cag island; the consequent cag instability may produce d...

show abstract

Section: Methodsmentioning

confidence: 99%

Heterogeneity of cag Genotypes in Helicobacter pylori Isolates from Human Biopsy Specimens

Tomasini¹,

Zanussi²,

Sozzi

et al. 2003

J Clin Microbiol

View full text Add to dashboard Cite

show abstract

“…The observation of transmissions from a mother to each of her children should be the means by which the route of infection is evaluated such that one can distinguish socially mediated transmission from a strictly vertical pathway. Third, transmission studies have typically used presence/absence measures of H. pylori infection via 13 C urea breath tests (Rothenbacher et al 1999;Tindberg et al 2001), presence/absence of antibodies (Tindberg et al 2001;Samir et al 2004), restriction enzyme digestion of amplified genes (Wang et al 1993), or analyses of peptide sequences (Prewett et al 1992). Although the latter two methods are an advance over 13 C urea breath tests as they allow comparison of H. pylori genotypes in parents and children, these methods do not provide the high resolution of nucleotide-sequencebased studies and are more susceptible to convergent changes.…”

mentioning

confidence: 99%

A Population Genetics Pedigree Perspective on the Transmission of Helicobacter pylori

et al. 2006

View full text Add to dashboard Cite

The inference of transmission pathways for medicinally important bacteria is important to our understanding of pathogens. Here we report analyses of transmission in Helicobacter pylori, a major carcinogen. Our study is novel in that the focal community comprises detailed family pedigrees and has a high prevalence of H. pylori. To infer transmission, we performed high-resolution analyses of nucleotide sequences for three genes and accounted for the occurrence of mutation and recombination through the use of simulation modeling. Our results demonstrate that transmission has a strong nonfamilial component potentially the result of a large proportion of infections derived from the community. These results are interesting from both a medical and an evolutionary standpoint. First, efficient control measures and beliefs about the sources of H. pylori infection should be reevaluated. Evolutionarily, our results contradict the hypothesis of strict vertical transmission, presented as an explanation for the strong correlation between human population history and H. pylori diversity. Thus the paradox of persistent phylogenetic structure, despite a permissive mode of transmission and high recombination rates, must be solved elsewhere. Here we consider the potential for recombination events to maintain genetic structure in light of horizontal transmission.

show abstract

“…First, H. pylori isolates from different humans can be readily distinguished by restriction fragment length polymorphism analysis of genomic DNA or specific genes (2,16,17,36) or by randomly amplified polymorphic DNA fingerprinting (1). Second, there is marked variation in the chromosomal maps of different H. pylori isolates (6,22,43).…”

mentioning

confidence: 99%

High-level genetic diversity in the vapD chromosomal region of Helicobacter pylori

Cao

Cover

1997

J Bacteriol

View full text Add to dashboard Cite

Helicobacter pylori isolates from different patients are characterized by diversity in the nucleotide sequences of individual genes, variation in genome size, and variation in gene order. Genetic diversity is particularly striking in vacuolating cytotoxin (vacA) alleles. In this study, five open reading frames (ORFs) were identified within a 4.2-kb region downstream from vacA in H. pylori 60190. One of these ORFs was closely related to the virulence-associated protein D (vapD) gene of Dichelobacter nodosus (64.9% nucleotide identity). A probe derived from vapD of H. pylori 60190 hybridized with only 19 (61.3%) of 31 H. pylori strains tested. Sequence analysis of the vapD region in vapD-negative H. pylori strains revealed that there were two different families of ϳ0.5-kb DNA segments, which were both unrelated to vapD. The presence of vapD was not associated with any specific family of vacA alleles. These findings are consistent with a recombinational population structure for H. pylori.Helicobacter pylori is the cause of chronic superficial gastritis in humans. Despite the persistence of H. pylori infection and associated gastric inflammation for many decades, the majority of H. pylori-infected humans remain relatively asymptomatic. However, about 20% of H. pylori-infected persons eventually develop peptic ulcers, and a smaller proportion develop gastric carcinoma or gastric lymphoma (11,(32)(33)(34). The pathophysiologic basis for these disparate outcomes is not yet completely understood, but there is increasing evidence that the clinical consequences of H. pylori infection may be determined, at least in part, by the genetic characteristics of the H. pylori strain with which a person is infected (3,7,13,29).Several lines of evidence indicate that H. pylori is a species characterized by considerable genetic diversity. First, H. pylori isolates from different humans can be readily distinguished by restriction fragment length polymorphism analysis of genomic DNA or specific genes (2,16,17,36) or by randomly amplified polymorphic DNA fingerprinting (1). Second, there is marked variation in the chromosomal maps of different H. pylori isolates (6,22,43). Third, the cag pathogenicity island and insertion sequence elements are present in some strains but not in others (7,21). Finally, multilocus enzyme electrophoresis data indicate that there is colossal allelic variation in this species (20).Genetic diversity among H. pylori isolates is particularly striking in vacuolating cytotoxin (vacA) alleles (3,10,14,35,37,45). vacA has a mosaic structure; it consists of several regions that are conserved and other regions that are highly divergent (3,10,14). Two families of vacA alleles (types m1 and m2) can be differentiated by analysis of the middle region of vacA, and three types of vacA signal sequences (s1a, s1b, and s2) can be differentiated (3). Within one 0.73-kb region of vacA, the nucleotide sequences of type m1 and m2 vacA alleles are only about 70% identical (3).In this study, we analyze a 4.2-kb region downstream fr...

show abstract

DNA patterns of Helicobacter pylori isolated from gastric antrum, body, and suodenum

Cited by 87 publications

References 12 publications

Heterogeneity of cag Genotypes in Helicobacter pylori Isolates from Human Biopsy Specimens

Heterogeneity of cag Genotypes in Helicobacter pylori Isolates from Human Biopsy Specimens

A Population Genetics Pedigree Perspective on the Transmission of Helicobacter pylori

High-level genetic diversity in the vapD chromosomal region of Helicobacter pylori

Contact Info

Product

Resources

About