Vacuolating cytotoxin A (VacA) is a secreted pore-forming toxin and one of the major virulence factors of Helicobacter pylori (H. pylori), which actively supports the persistence and survival of the bacteria in the special ecological niche of the human stomach. H. pylori genomes harbor different allelic forms of the vacA gene, which translate into functionally distinct VacA toxin types. VacA in...

The prevalence of clarithromycin resistance-associated mutations, the cytotoxin-associated gene (cagA), and the various vacuolating cytotoxin (vacA) genotypes was determined in 50 gastric biopsy specimens from Helicobacter pylori-infected patients, using line probe assays. The clarithromycin resistance-associated mutation A2143G was detected in H. pylori strains from 26% of the specimens, which...

Helicobacter pylori produces a vacuolating cytotoxin, VacA, and most virulent H. pylori strains secrete VacA. VacA binds to two types of receptor-like protein tyrosine phosphatase (RPTP), RPTPalpha and RPTPbeta, on the surface of host cells. VacA bound to RPTPbeta, relocates and concentrates in lipid rafts in the plasma membrane. VacA causes vacuolization, membrane anion-selective channel and p...

The aim of this study was to determine the presence of Helicobacter pylori cytotoxin-associated gene (cagA)/vacuolating cytotoxin gene (vacA) among patients with chronic gastritis in Cuba and Venezuela. Gastric antrum biopsies were taken for culture, DNA extraction and PCR analysis. Amplification of vacA and cagA segments was performed using two regions of cagA: 349 bp were amplified with the F...

BACKGROUND The cytotoxin associated gene A (cagA), and the vacuolating cytotoxin gene A (vacA) of Helicobacter pylori have been associated to phenotypic characteristics of virulence. The objectives of this study were to detect the presence of cagA and to characterize the allelic variants of vacA in 63 strains of H. pylori isolated from colonized individuals with different clinical outcomes. M...

background : helicobacter pylori ( h. pylori ) infection is known as a major etiologic factor for a variety of gastroduodenal diseases. in iran, with a high rate of h. pylori infection close to 90%, numerous studies have revealed many aspects of interaction between the bacterium, mucosal surface and induction of disease outcome. the organism is genetically diverse and several virulence factors ...

The interrelationship between cytotoxin-associated gene A (CagA), vacuolating cytotoxin (VacA), and Helicobacter pylori-related diseases was investigated in 155 H. pylori-infected patients. Four (7%) of 60 subjects had mixed cagA+ and cagA- H. pylori infections. The H. pylori isolates from 98.3% of 121 patients with anti-CagA antibodies were cagA+. The occurrence of cagA+ H. pylori among 76 pat...

UNLABELLED Objective(s) : Helicobacter pylori, a human specific gastric pathogen is a causative agent of chronic active gastritis. The vacuolating cytotoxin (VacA) is an effective virulence factor involved in gastric injury. The aim of this study was to construct a recombinant protein containing antigenic region of VacA gene and determine its antigenicity. MATERIALS AND METHODS The antigenic ...

BACKGROUND To evaluate the prevalence of more virulent H. pylori genotypes in relatives of gastric cancer patients and in patients without family histories of gastric cancer. METHODS We evaluated prospectively the prevalence of the infection by more virulent H. pylori strains in 60 relatives of gastric cancer patients comparing the results with those obtained from 49 patients without family h...

Helicobacter pylori, a gram-negative bacterium, possesses two important virulence factors: the vacuolating toxin (vacA), and the cytotoxin-associated gene product (cagA). The aim of the present study was to evaluate the presence of H. pylori in the stomach and oral cavity of humans and compare the cagA and vacA genotypes of H. pylori found in different samples (stomach, saliva and dental plaque...