Which bacterium is most commonly associated with gastritis and peptic ulcer disease?

Helicobacter pylori is the bacterium most commonly associated with gastritis and peptic ulcer disease due to its unique ability to survive in the harsh acidic environment of the stomach. It does this by producing urease, an enzyme that converts urea to ammonia, neutralizing stomach acid and allowing the bacteria to colonize the gastric epithelium.

The chronic infection by H. pylori can lead to inflammation of the gastric mucosa, known as chronic gastritis, and is a significant risk factor for the development of peptic ulcers, which are sores that can form in the stomach lining or the upper part of the small intestine. H. pylori is also linked to certain gastric malignancies, making its identification and treatment clinically significant.

In contrast, other bacteria listed are associated with different conditions: Escherichia coli is often involved in gastrointestinal infections, particularly diarrhea; Salmonella enterica is associated with enteric fever and foodborne illnesses; and Clostridium difficile is primarily linked to antibiotic-associated colitis rather than peptic ulcer disease.