Which bacteria is primarily responsible for Peptic Ulcer Disease?

Peptic ulcer disease is primarily caused by the bacterium Helicobacter pylori. This gram-negative bacterium has adapted to survive in the acidic environment of the stomach and is directly implicated in the development of both gastric and duodenal ulcers. H. pylori disrupts the protective mucous lining of the stomach and duodenum, leading to inflammation (chronic gastritis) and ulceration.

The pathogenic mechanisms of H. pylori include the production of urease, which neutralizes stomach acid, allowing the bacteria to thrive and causing damage to the epithelial cells. This damage can result in increased acid production and a deterioration of the mucosal barrier, contributing to ulcer formation. Additionally, the presence of H. pylori is associated with an increased risk of gastric cancer, further underscoring its clinical significance.

In contrast, the other options listed do not play a significant role in peptic ulcer disease. Escherichia coli is primarily known for causing gastrointestinal infections but is not associated with peptic ulcers. Streptococcus pneumoniae is a common cause of pneumonia and other infections primarily affecting the respiratory system, and it has no relevance in the context of peptic ulcers. Helminths are parasitic worms that can cause various diseases but do