Which organism is commonly associated with peptic ulcers?

• A. Helicobacter pylori
• B. Escherichia coli
• C. Staphylococcus aureus
• D. Candida albicans

Answer: (A)

Peptic ulcers are most strongly linked to infection with Helicobacter pylori. This curved bacterium colonizes the stomach lining despite the acidic environment, uses urease to convert urea into ammonia, and thereby neutralizes local acid enough to survive. The ongoing presence of H. pylori provokes chronic inflammation and damages the protective mucous layer, letting gastric acid injure the mucosa and form ulcers in the stomach or duodenum. Eradicating the organism with antibiotics plus acid-suppressing therapy often leads to healing and prevents recurrence. The other organisms listed are associated with different infections—E. coli with various GI infections, Staphylococcus aureus with skin infections and food poisoning, and Candida albicans with thrush or invasive candidiasis—so they are not the typical causes of peptic ulcers.