Infection of the gastric mucosa leading to gastritis or peptic ulcers is most commonly associated with which organism?

• A. Campylobacter jejuni
• B. Helicobacter pylori
• C. Salmonella Typhi
• D. Shigella sonnei

Answer: (B)

Infection of the gastric mucosa that leads to gastritis or peptic ulcers is most strongly linked to Helicobacter pylori because it can survive the acidic stomach environment and cause chronic inflammation. This curved, Gram-negative bacterium makes urease, which splits urea into ammonia and carbon dioxide. The ammonia locally neutralizes stomach acid, allowing the bacteria to colonize the gastric mucosa and trigger ongoing inflammation that damages the protective lining. Over time, this inflammation disrupts the mucous barrier and underlying tissue, promoting gastritis and peptic ulcer formation. It’s the classic association for these conditions and also ties into other gastric diseases if the infection persists. Tests to detect it include the urea breath test or stool antigen test, and diagnosis can also be made via endoscopic biopsy with a rapid urease test. Other organisms listed are not characteristically associated with chronic gastric ulcers in the same way: they may cause gastroenteritis or systemic illness, but not the typical pattern of chronic gastric infection and ulceration seen with Helicobacter pylori.