cagA gene and vacA alleles in Spanish Helicobacter pylori clinical isolates from patients of different ages

Alarcón, T

doi:10.1016/s0928-8244(99)00029-2

Cited by 23 publications

(25 citation statements)

References 7 publications

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“…However, for adult strains these genes showed a homogeneous distribution within ulcer and gastritis strains. These results are in agreement with other studies that highlighted important differences in strains infecting the mucosa of adults and children (4,25,45).…”

Section: Discussionsupporting

confidence: 93%

Identification of Markers for Helicobacter pylori Strains Isolated from Children with Peptic Ulcer Disease by Suppressive Subtractive Hybridization

et al. 2006

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Peptic ulcer disease (PUD) occurs after a long-term Helicobacter pylori infection. However, the disease can develop earlier, and rare cases have been observed in children, suggesting that these H. pylori strains may be more virulent. We used suppressive subtractive hybridization for comparative genomics between H. pylori strains isolated from a 5-year-old child with duodenal ulcer and from a sex-and age-matched child with gastritis only. The prevalence of the 30 tester-specific subtracted sequences was determined on a collection of H. pylori strains from children (15 ulcers and 30 gastritis) and from adults (46 ulcers and 44 gastritis). Two of these sequences, jhp0562 (80.0% versus 33.3%, P ‫؍‬ 0.008) and jhp0870 (80.0% versus 36.7%, P ‫؍‬ 0.015), were highly associated with PUD in children and a third sequence, jhp0828, was less associated (40.0% versus 10.0%, P ‫؍‬ 0.048). Among adult strains, none of the 30 sequences was associated with PUD. However, both jhp0562 and jhp0870 were less prevalent in adenocarcinoma strains than in PUD strains from children and adults, the difference being statistically significant for jhp0870. In conclusion, two H. pylori genes were identified as being strongly associated with PUD in children, and their putative roles as an outer membrane protein for jhp0870 and in lipopolysaccharide biosynthesis for jhp0562, suggest that they may be novel virulence factors of H. pylori.Helicobacter pylori, a spiral-shaped gram-negative bacterium, can lead to various gastroduodenal diseases. A causal association has been established with chronic gastritis, peptic ulcer, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma (10). The mechanisms for such a clinically diverse profile are not totally clear but may include host and environmental factors, as well as bacterial virulence factors (7,20,23,47).In adult patients, severe gastroduodenal diseases such as duodenal ulcer, gastric adenocarcinoma, and MALT lymphoma occur after a long-term colonization (22, 47), while the onset of H. pylori infection is essentially during childhood (26). Indeed, the majority of H. pylori-infected children remain asymptomatic, except for a very small group which will develop peptic ulcer. Other factors such as nonsteroidal anti-inflammatory drug use, physiologic stress, and vascular insufficiency also play an important role beside H. pylori infection in the development of peptic ulcer in children (28). Moreover, colonization with H. pylori strains that are considered virulent in adults does not always correlate with the severity of endoscopic and histologic findings in children (24). These conflicting results may be due to the short-term infection, the association becoming possibly stronger as the duration of infection increases (53). Ulcers in children, in contrast to adults, appear shortly after H. pylori colonization, suggesting that differences exist between the ulcerogenic strains which infect children and adults and that strains associated with peptic ulcer in children may be m...

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Section: Discussionsupporting

confidence: 93%

Identification of Markers for Helicobacter pylori Strains Isolated from Children with Peptic Ulcer Disease by Suppressive Subtractive Hybridization

et al. 2006

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“…Here, 73.2% of the H pylori strains were cagA-positive, a prevalence similar to that reported in many studies from Western countries (e.g. USA, 60% [7] ; Spain, 66% [26] ; and England, 68% [27] ) but lower than that reported in some East Asian studies, which encountered over 90% of cagApositive isolates (Table 4) [25,28] . In addition, a highly significant correlation was observed between cagA status and vacAs1 and vacAs1m1 genotypes (Table 2), which is commonly linked to an increase in H pylori virulence [13,14,29,30] .…”

Section: Vaca Allelessupporting

confidence: 86%

“…Moreover, a high frequency of cagA-positive strains was observed in DU patients ( Table 3), indicating that a statistical association could be reached by increasing the number of patients in future studies. [14,23,26,27] 66-73 [14,23,26,27] 34-72 [13,14,34] America 57-68 16-48 37-44 29-63 [19,20,24] 57-75 [7,19,24] 46-69 [24,32] East Asia 100 0 41-94 5-55 [12,25,28] 90-100 [12,25,28,35] 80-100 [12,21,35] Torres…”

Section: Vaca Allelesmentioning

confidence: 99%

Prevalence of vacA, cagA and babA2 genes in Cuban Helicobacter pylori isolates

Torres¹,

Melián²,

Moreno³

et al. 2009

WJG

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and seven isolates (82.3%) were babA2 -positive. A significant correlation was observed between vacAs1m1 a n d c a g A a n d b e t w e e n va c A s 1 m 1 a n d b a b A 2 genotypes (P < 0.001 and P < 0.05, respectively) and between babA2 genotype and cagA status (P < 0.05); but, no correlation was observed between vacAs1 and babA2 genotypes. Eighty five (65.4%) and 73 (56.2%) strains were type 1 (vacAs1 -cagA -positive) and "triplepositive" (vacAs1 -cagA -babA2 -positive), respectively, and their presence was significantly associated with duodenal ulcer (P < 0.01 and P < 0.001, respectively). CONCLUSION:The distribution of the main virulence factors in the Cuban strains in this study resembled that of the Western-type strains, and the more virulent H pylori isolates were significantly associated with duodenal ulcer, ulcer disease being the worst pathology observed in the group studied.

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“…The less pathogenic type II genotype is the most frequently found genotype in Portuguese children with nonulcerative gastritis and has been reported in other similar pediatric populations (2,14,39).…”

Section: Discussionmentioning

confidence: 53%

Cytokine Expression in PediatricHelicobacter pyloriInfection

Lopes

Quiding‐Järbrink

Palha

et al. 2005

Clin Vaccine Immunol

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Helicobacter pylori infection is one of the most common gastrointestinal infections worldwide and almost invariably causes chronic gastritis in the infected host. A predominant Th1 profile has been demonstrated in H. pylori-infected mucosa from adults, but no previous study has evaluated in situ cytokine expression in children. We therefore examined expression of proinflammatory, anti-inflammatory, and regulatory cytokines by immunohistochemistry in cryopreserved antral biopsy specimens from 10 H. pylori-infected and 10 uninfected children and correlated expression of cytokines with histology scores. Concomitant expression of interleukin-8 (IL-8), gamma interferon (IFN-␥), IL-4, transforming growth factor ␤, and tumor necrosis factor alpha was seen in 8/10 H. pylori-infected cases and in 5/10 noninfected cases; all H. pylori-infected subjects showed staining for at least two of the cytokines. The proportion of epithelial cytokine-specific staining did not differ significantly between the groups, either in surface or glandular epithelium. Furthermore, no significant differences were noticed between intraepithelial or lamina propria lymphocyte staining in the groups. There was, however, a tendency of higher numbers of IFN-␥-and IL-8-positive cells in the H. pylori-infected group. IFN-␥ and IL-8 lamina propria lymphocyte expression correlated significantly with antrum chronic inflammation, but there was no correlation between histology scores and epithelial cytokine expression. When the same techniques were used, the cytokine response appeared to be smaller in H. pylori-infected children than in adults, and there was no clear Th1 dominance. These results therefore suggest a different mucosal immunopathology in children. It remains to be determined whether the gastric immune response is downregulated in children with H. pylori infection and whether this is relevant to the outcome of infection.

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cagA gene and vacA alleles in Spanish Helicobacter pylori clinical isolates from patients of different ages

Cited by 23 publications

References 7 publications

Identification of Markers for Helicobacter pylori Strains Isolated from Children with Peptic Ulcer Disease by Suppressive Subtractive Hybridization

Identification of Markers for Helicobacter pylori Strains Isolated from Children with Peptic Ulcer Disease by Suppressive Subtractive Hybridization

Prevalence of vacA, cagA and babA2 genes in Cuban Helicobacter pylori isolates

Cytokine Expression in PediatricHelicobacter pyloriInfection

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