Helicobacter pylori vacA virulence gene analysis and association with clinical and histopathological aspects in dyspeptic patients
Helicobacter pylori is a Gram-negative oncobacterium that affects more than 50% of the world population. The differing clinical outcomes resulting from H. pylori infection are the result of host-pathogen interactions. The vacuolating cytotoxin A (vacA) gene is considered an important virulence factor in H. pylori as it has been associated with gastric complications. The aim of this study was to detect the H. pylori vacA genotype and determine if it is associated with gastropathies. A total of 117 gastric biopsy samples were collected from dyspeptic patients in central Brazil. The detection of the microorganism was performed using specific primers for the 16S rRNA and vacA genes. Subsequently, gastric pathologies were classified as severe (atrophy, metaplasia and adenocarcinoma) and non-severe (esophagitis, duodenitis, gastritis and ulcers) based on histopathological examination. A total of 80 patients were H. pylori positive and (56%) of those were vacA positive. Infection with the positive H. pylori vacA strain was more prevalent in patients over the age of 45 years. Gastric diseases were diagnosed in 91% of patients infected with H. pylori. Gastritis was the most common histopathological finding in the positive (69%) and negative (70%) vacA groups (p=1.00). However, there were no significant associations between H. pylori vacA-positive status, sociodemographic characteristics, and clinical outcomes. The vacA gene was not found to be a marker of the severity of gastric lesions in our study (OR: 0.70, P=0.67). Nevertheless, the vacA gene was found to have a high prevalence in H. pylori isolates from gastric lesions in these Brazilian patients. Given this high frequency and what is known about this virulence factor, it would be useful to evaluate the interaction of vacA with other genes that affect the severity of gastric lesions.