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...

Polarized epithelial monolayers of Madin-Darby canine kidney (MDCK) cells were used to study the pathogenicity of Helicobater pylori, with an emphasis on the effect of VacA. The adherence of H. pylori to MDCK monolayers resulted in a decrease in trans-epithelial resistance (TER) across the cell monolayer. Isogenic vacA mutants did not lower the TER, demonstrating that the effect is strictly lin...

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 region of v...

background: helicobacter pylori strains have two classical virulence genes, the cytotoxinassociated a ( caga ) gene and the vacuolating cytotoxin a ( vaca ) gene, which are located in the cag pathogenicity island ( cag pai). serum immunoglobulin g (igg) antibodies to h. pylori , especially, the caga antigen may be a reliable marker for selection of dyspeptic patients for upper endoscopy. method...

background and objective: helicobacter pylori has several strains with different degrees of virulence. the aim of this study was to detect two major important virulence factors, caga/vaca genotypes, and to determine correlations among different caga/vaca genotypes and histological features of chronic gastritis in iranian patients. methods: in this cross- sectional study, gastric biopsy was take...

VacA is a secreted toxin that plays a role in Helicobacter pylori colonization of the stomach and that contributes to the pathogenesis of peptic ulcer disease. Studies of VacA structure and function have been hindered by the lack of an efficient system for expression and genetic manipulation of this toxin. In this study, we developed methodology for expression of a functionally active VacA toxi...

BACKGROUND In this study, we evaluated the prevalence of primary resistance of Brazilian H. pylori isolates to metronidazole, clarithromycin, amoxicillin, tetracycline, and furazolidone. In addition, the vacA, iceA, cagA and cagE genotypes of strains isolated from Brazilian patients were determined and associated with clinical data in an effort to correlate these four virulence markers and anti...