How does H. pylori survive in the acidic pH of the stomach?

Colonises the mucin layer that covers the gastric mucosa. Mucus resists diffusion of protons from stomach acid because it is composed of negatively charged sulphated polysaccharides. Urease hydrolyses the urea secreted by gastric cells to produce ammonia and CO2. The urease is intracellular exports ammonia very efficiently to the periplasm.