Helicobacter pylori

📚 Related Subjects: | Listeriosis | Moraxella catarrhalis | Leptospira interrogans | Lactobacillus acidophilus | Helicobacter pylori | Haemophilus parainfluenzae | Haemophilus influenzae

🎯 Treatment of H. pylori aims to eradicate infection, reduce peptic ulcer disease and bleeding risk, and prevent recurrence, gastric cancer, and MALT lymphoma.

📖 About

• Discovered by Barry Marshall & Robin Warren in 1982 🧪.
• Most common cause of peptic ulceration, though many carriers are asymptomatic.
• Present in ~95% of duodenal ulcers and 70–80% of gastric ulcers.
• NSAIDs + H. pylori = 🔥 high ulcer risk.
• Associated with acute/chronic gastritis, gastric adenocarcinoma, and MALT lymphoma (regresses after eradication in many cases).

🔬 Electron Microscopy

🌍 Source

• Spread mainly person-to-person → oral–oral or faeco–oral.
• More common in older adults and in lower socioeconomic groups.
• Humans are the main reservoir (occasionally found in cats 🐈).

⚙️ Characteristics

• Spiral-shaped, Gram-negative, highly motile bacillus.
• Microaerophilic with 4–6 unipolar flagella.
• Urease production → breaks down urea to ammonia → neutralises gastric acid locally.
• Lives beneath gastric mucous layer and adheres to epithelial cells.

🧨 Virulence

• Causes neutrophilic gastritis.
• CagA gene linked to severe disease and higher gastric cancer risk.
• Produces urease and VacA toxin → epithelial injury.

🩺 Pathogenicity

• Antral gastritis → achlorhydria + ↑ gastrin + ↑ acid secretion.
• Chronic duodenal ulcers (95% cases) & gastric ulcers (70–80%).
• Gastric cancer: adenocarcinoma (80% linked to H. pylori).
• MALT lymphoma: may regress after eradication.

🧪 Investigations

• 🩸 Serology: Detects IgG → cannot distinguish past from current infection.
• 💨 Urea Breath Test (13C/14C): Most accurate non-invasive test.
• 💩 Stool Antigen Test (SAT): Confirms active infection.
• 🔬 Histology + biopsy urease (CLO test): High sensitivity/specificity.
• 🧫 Culture: Gold standard but slow (used for resistance testing).

🧾 NICE/CKS testing rule (important): for UBT or stool antigen, stop PPI for 2 weeks and avoid antibiotics for 4 weeks beforehand (false negatives otherwise). If you must treat symptoms, consider an H2 blocker/antacid short-term and re-test later.

💊 Management (UK – NICE/BNF-aligned)

• First-line (Triple Therapy): for 7 days (choose based on prior antibiotic exposure)
  • PPI BD (e.g., omeprazole 20 mg BD or equivalent)
  • Amoxicillin 1 g BD
  • Either clarithromycin 500 mg BD OR metronidazole 400 mg BD
• Penicillin allergy (Triple Therapy): for 7 days
  • PPI BD (e.g., omeprazole 20 mg BD or equivalent)
  • Clarithromycin 250 mg BD
  • Metronidazole 400 mg BD
• Second-line (if failure / persistent symptoms): for 7 days (switch the antibiotic not used first-line)
  • PPI BD (e.g., omeprazole 20 mg BD or equivalent)
  • Amoxicillin 1 g BD
  • Either clarithromycin 500 mg BD OR metronidazole 400 mg BD — choose the one not used first line
• When eradication is indicated:
  • Peptic ulcer disease (gastric & duodenal)
  • MALT lymphoma
  • Post-bleed ulcers & atrophic gastritis
• Routine screening for asymptomatic carriers is not recommended in low-risk groups.

✅ Confirm eradication (test-of-cure) & follow-up (NICE/CKS aligned)

🔁 Don’t “assume cured”. If re-testing is indicated, use a 13C urea breath test or stool antigen test (not serology), and time it correctly to avoid false negatives. NICE quality standards emphasise a 2-week PPI washout before testing, and CKS advises waiting long enough after antibiotics.

• Who should have a test-of-cure? (common UK indications)
  • 🩸 Peptic ulcer disease (gastric or duodenal), especially if complicated (bleed/perforation) or high-risk recurrence.
  • 🎗️ MALT lymphoma (proof of eradication is essential as it can drive remission).
  • 🧪 Persistent or recurrent symptoms after eradication therapy (particularly if initial testing conditions were suboptimal).
  • 💊 High concern about failure (poor adherence, prior macrolide/metronidazole exposure, suspected resistance).
• When to re-test (timing rules):
  • ⏱️ Arrange re-testing at least 4 weeks after completing eradication antibiotics (ideally 8 weeks in many pathways).
  • ⛔ Stop PPI for 2 weeks before the breath test / stool antigen test (NICE QS96).
  • ⛔ Avoid antibiotics for 4 weeks before testing (CKS advice) to reduce false negatives.
• Choice of test:
  • 💨 13C urea breath test = excellent non-invasive “test-of-cure”.
  • 💩 Stool antigen test = also confirms active infection and is suitable for “test-of-cure”.
  • 🩸 Serology is not appropriate for confirmation (IgG can stay positive for months/years).
• What if symptoms persist but test-of-cure is negative?
  • Consider functional dyspepsia, GORD, ongoing NSAID injury, biliary disease, pancreatitis, malignancy, or alternative infection.
  • If alarm features develop (weight loss, dysphagia, GI bleed, anaemia, persistent vomiting): follow urgent endoscopy pathways.
• What if the test-of-cure is positive (treatment failure)?
  • ✅ Check adherence, dosing, and whether the patient was on a PPI at the time of testing.
  • 🔁 Use a different second-line regimen (usually switching the antibiotic not used first-line) per CKS/local antimicrobial guidance.
  • 🧫 After ≥2 failures, consider endoscopy for culture/susceptibility and specialist input (local pathway).
• Gastric ulcer follow-up (important NICE/CKS point):
  • 🩻 Ensure all patients with a proven gastric ulcer have repeat endoscopy to confirm healing and exclude malignancy; arrange H. pylori re-testing if appropriate (CKS).

📚 Guideline links (UK)

• NICE QS96: 2-week PPI washout before H. pylori testing
• NICE CKS: Dyspepsia (unidentified cause) – H. pylori test/treat + re-test timing
• NICE CKS: Proven peptic ulcer – repeat endoscopy for gastric ulcer + H. pylori follow-up
• UK “Test and treat” quick reference (PHE/NICE-linked PDF)

📚 References

• BNF (NICE): Helicobacter pylori infection – treatment summary
• NICE CKS: Dyspepsia (unidentified cause) – H. pylori “test and treat” and regimens