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

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

Answer: (D)

Infection of the stomach lining that leads to gastritis and peptic ulcers is most strongly linked to a curved, microaerophilic Gram-negative bacterium that survives in the acidic gastric environment by producing urease. By converting urea to ammonia, it locally neutralizes acid, allowing the organism to colonize the gastric mucosa and trigger chronic inflammation and mucosal damage that can progress to ulcers. Among the options, this organism best fits that pattern, as it is the principal cause of chronic gastritis and peptic ulcers worldwide. The other organisms are more typically associated with acute gastroenteritis or systemic illness rather than a persistent gastric infection leading to ulcers.