Gastric Ulcer and Helicobacter Pylori Case Study

Case Presentation

• A 48-year-old man presents with a 2-month history of upper abdominal pain, associated with nausea.
• Symptoms are exacerbated by coffee, soda, or alcohol consumption.
• Antacids provide temporary relief.
• Patient has a history of smoking for 20 years, occasional alcohol use, and frequent NSAID use.
• Physical examination and vital signs are normal.
• Abdominal examination reveals epigastric tenderness.
• CBC shows mild hypochromic, microcytic anemia.
• Upper GI endoscopy reveals diffuse gastritis and a gastric ulcer.

Helicobacter pylori

• Helicobacter pylori is a spiral, Gram-negative bacterium, measuring 3 x 0.5-0.9 µm.
• Possesses a single polar tuft of flagella for motility.
• Requires microaerophilic conditions for growth: 10% CO2, 5% O2, 85% N2.
• Does not grow anaerobically.
• Grows optimally at 37°C.
• Requires high humidity and 5-10% CO2 for growth.
• Isolates can be grown on specialized media, including Butzler's medium, Skirrow's medium (similar to chocolate agar), and other media containing antibiotics like cefazolin, bacitracin, nalidixic acid, and amphotericin.
• Colonies are typically small, translucent, gray, 1-2 mm in diameter, and weakly β-hemolytic.
• Most H. pylori strains take 3-7 days to grow in culture.

Biochemical Characteristics of Helicobacter pylori

• Positive for catalase and oxidase.
• Weakly positive for H2S production.
• Positive for urease activity.
• Susceptible to cephalotin (30 µg) and resistant to nalidixic acid (30 µg).

H. pylori Pathogenesis

• Considered the primary risk factor for peptic ulceration, gastric adenocarcinoma, and gastric MALT (mucosa-associated lymphoid tissue) lymphoma.
• Colonizes the stomach of approximately 50% of the global population.
• Infection is present in 70%-90% of individuals with duodenal ulcers and approximately 70% of those with gastric ulcers.
• Antibiotic treatment of H. pylori infection promotes healing of ulcers and reduces their recurrence.

Virulence Factors

• H. pylori has several virulence factors that facilitate colonization of the stomach:
  • Acid-inhibitory protein: Blocks acid production.
  • Urease: Neutralizes stomach acid by producing ammonia.

Diagnosis

• Microscopy: Visualizing H. pylori on a gastric biopsy specimen.
• Rapid urease test: Detect urease activity, indicating H. pylori presence.

Other Helicobacter Species Associated with Human Disease

• H. heilmannii: Associated with gastritis.
• H. cinaedi and H. fennelliae: Associated with gastroenteritis, septicemia, and proctocolitis.