Association of cagA+ Helicobacter pylori strains with high urease activity and dyspepsia in Mexican adults

Abstract

Introduction and aims: Helicobacter pylori (H. pylori) is associated with a higher risk of peptic ulcer and gastric cancer. The sole presence of the bacterium is not a determinant of clinical outcome, but rather the interaction of strain type and host factors determines the risk of disease. Our aim was to study the association between bacterial load, strain type, and gastric symptoms in H. pylori-positive subjects.

Materials and methods: In a community survey, a diagnostic ¹³C-urea breath test for H. pylori was performed on 302 volunteers that were not taking antibiotics, antacids, or proton pump inhibitors one month prior to the test. The breath test produced 25 H. pylori-positive subjects, between 25-74 years of age, who then took a gastric symptoms survey and were tested for the presence of the cagA genotype in gastric juice, using the Entero-test®. Bacterial load was determined as a measure of urease activity, utilizing the delta over baseline value, obtained in the ¹³C-urea breath test.

Results: A total of 48% of the H. pylori-positive subjects were cagA+. A positive association was found between cagA status and high gastric urease activity (P<.0001) and the latter was significantly associated with the presence of symptoms (P<.0001).

Conclusion: Gastric urease activity was strongly associated with dyspeptic symptoms and cagA+ H. pylori. Elevated ¹³C-delta over baseline values could be used as indicators of a higher risk for gastric disease.

Keywords: Dispepsia; Dyspepsia; Genotipo cagA; Helicobacter pylori; Prueba de la ureasa en aliento; Urea breath test; cagA genotype.