Abstract
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) from the same patient. Gastric biopsies, saliva and dental plaques were obtained from 62 dyspeptic adults. DNA was extracted and evaluated for the presence of H. pylori and the alleles cagA and vacA. Persons with gastritis had a higher frequency of H. pylori -positive samples in the stomach while positive samples from gastric biopsies were significantly correlated with those from the oral cavity. There was a high H. pylori frequency in patients while the cagA gene was associated with vacA s1 alleles in gastric biopsies. Our results suggest a reservoir of the species in the oral cavity and that, in one patient, more than one H. pylori strain may exist in the saliva, dental plaque and stomach. We found a relationship between gastric infection and the bacterium in the oral cavity, with the cytotoxin genotype varying between saliva and dental plaque.
Highlights
Helicobacter pylori is a spiral-shaped gramnegative flagellate bacterium that has been implicated as a major human gastric pathogen responsible for gastritis and peptic ulcer disease [1]
We found significant genotypic diversity among H. pylori cytotoxins from the stomach, saliva and dental plaque samples, which corroborates the work of Wang et al [32]
There is a high prevalence of H. pylori and the main virulence factor genes in Brazilian H. pylori isolates, namely the cagA gene, appears to be associated with vacuolating cytotoxin A (vacA) s1 alleles in gastric biopsies
Summary
Helicobacter pylori is a spiral-shaped gramnegative flagellate bacterium that has been implicated as a major human gastric pathogen responsible for gastritis and peptic ulcer disease [1]. The high prevalence of the disease has propelled an extensive search for H. pylori virulence factors. The vacA gene is present in all H. pylori strains, and comprises two main regions that show significant sequence variability between strains: the signal region (s1 or s2) and the middle region (m1 or m2). These two parts of vacA gene determine cytotoxin production and are associated with pathogenicity of the bacterium. The vacA protein induces vacuolation and apoptotic processes in epithelial cells, as well as immunosuppressive effects in immunological cells [9]
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