RESUMO
Helicobacter pylori [H. pylori], a major aetiological agent in gastritis, peptic ulcer and gastric cancer, is estimated to infect more than 50% of the world's population. However, only about 10% will develop peptic ulcer disease and 1 - 2% gastric malignancy. Virulent strains carrying the cag A gene and vac A s1 genotype and capable of cytotoxin production have been proposed to be associating with the severer forms or disease, although this was not universal. We were interested in studying the relation between cytotoxin-producing H. pylori strains and the H. pylori-related upper gastrointestinal disease in our community. Sixty patients were allocated into 3 predefined groups according to their endoscopic picture: gastroesophageal reflux disease [GERD], peptic ulcer disease, and gastritis groups. Gastric biopsies from the patients were examined for the presence of H. pylori by urease test and culture. The isolated H. pylori strains were subjected to cytotoxic assay to detect cytotoxin-producing strains. Forty-one patients [68.3%] were H. pylori positive, of them 19 [46.3%] were positive for cytotoxin production. Cytotoxin-producing H. pylori strains significantly associated peptic ulcer disease where 73.3% of peptic ulcer patients were infected with cytotoxin-producing strains. GERD was significantly associated with absence of H. pylori infection [66.7% of GERD patients were free of H. pylori infection]. The presence of gastritis did not correlate with the H. pylori status, however, there was a significant association between cytotoxin-producing strains and atrophic gastritis. Cytotoxin-producing H. pylori strains are associated with severer H. pylori-related upper gastrointestinal diseases such as atrophic gastritis and peptic ulcer disease. Our findings support the hypothesis of cag A [+] H. pylori being protective against GERD. Determination of cag A status of H. pylori strains bears importance in clinical practice in detecting patients at increased risk for developing gastric cancer and in helping planning treatment strategies