Most other types of bacteria do not produce ulcers because they cannot survive the highly acidic environment of the stomach. Helicobacter pylori, the primary bacterium responsible for ulcers, uniquely survives stomach acid by producing large amounts of the enzyme urease, which breaks down urea to produce ammonia and bicarbonate. This neutralizes the acid around the bacteria, allowing it to colonize the protective mucus lining of the stomach and damage the stomach lining, leading to ulcers. Additionally, H. pylori produces adhesins to attach to stomach cells and has a spiral shape that helps it burrow through the mucus. These specialized adaptations are not found in most other bacteria, which cannot colonize or survive in the stomach's acidic conditions to cause ulcers.

Reasons other bacteria don't cause ulcers:

• Most bacteria cannot survive the acidic gastric environment.
• H. pylori neutralizes acid locally with urease enzyme.
• H. pylori adheres to stomach lining using specific proteins.
• H. pylori burrows through mucus with its spiral shape.
• Other bacteria lack these survival and colonization mechanisms.

Thus, the unique biochemical and physical adaptations of H. pylori enable it to cause ulcers, unlike most other bacteria.