Helicobacter Pylori (H. pylori)

See gord-pud.md for the broader GORD/peptic ulcer disease work-up this page sits within.

Red flags

Difficulty/pain on swallowing; unexplained weight loss with GI symptoms; unexplained iron deficiency anaemia; haematemesis or melaena — arrange urgent gastroenterology referral for any of these rather than test-and-treat.

Background

~30% of adult Australians are infected — more likely if older, migrant, lower socioeconomic status, or living in institutions. Most acquisition occurs in childhood, more frequent in family members of an infected person and with a family history of peptic ulcer disease or gastric cancer. Lifetime risk if colonised: gastric/duodenal ulcer 15–20%, gastric cancer 2% — most infected people remain asymptomatic with gastritis only.

Patients with symptoms of GORD without dyspepsia or another indication below do not need testing.

Indications for testing

Indication	Benefit if positive and treated
Peptic ulcer disease (past or present)	Heals ulcers, reduces relapse
Dyspepsia	May reduce symptoms and long-term PUD/gastric cancer risk
Selected NSAID users (including aspirin)	Reduces PUD and GI bleeding risk
Atrophic gastritis / intestinal metaplasia	Reduces long-term gastric cancer risk
Long-term acid suppression	Reduces progression of intestinal metaplasia
Family history of gastric cancer or gastric MALT lymphoma	Reduces long-term gastric cancer risk
Previously treated early gastric cancer	Reduces risk of further gastric cancer
Low-grade gastric MALT lymphoma	Induces lymphoma regression
Patient’s own wishes, after discussing harms/benefits	Fulfils patient preference

Risk factors for infection: age >60, past PUD, at-risk ethnicity (Aboriginal and Torres Strait Islander, Pacific, Asian), migration from a high-risk area.

Symptoms suggestive of serious underlying pathology (any of these mean endoscopy, not test-and-treat): difficulty/painful swallowing, unexplained weight loss with GI symptoms, unexplained iron deficiency anaemia, haematemesis/ melaena, first presentation of unexplained persistent dyspepsia/GORD aged ≥55yrs, or family history of gastric cancer with onset <50yrs in the relative.

Testing

Urea breath test (UBT) — the preferred non-invasive test. Mechanism: ingested radio-labelled urea is metabolised by H. pylori, producing labelled CO₂ that is measured on the breath. Sensitivity 90–96%, specificity 88–98%; turnaround ~3 weeks. Before testing: fasting, no antibiotics/bismuth for 4 weeks, no PPI for 2 weeks (H2-antagonists/antacids/alginates are fine). Repeat UBT at least 4 weeks after completing eradication therapy, with the same PPI washout, as the test-of-cure.

Stool antigen test — mostly superseded by UBT but still available at some labs; sensitivity 88–98%, specificity 89–98%. Same pre-test washout requirements. Can be used post-treatment (some debate about reliability in this role).

Serology — inexpensive but not suitable for post-eradication monitoring (antibody levels don’t fall promptly after successful treatment) and not accurate enough alone for clinical decision-making.

Invasive tests (via gastroscopy, rarely first-line in general practice): rapid urease test (quick, inexpensive, highly sensitive/specific, but needs a repeat scope for test-of-cure so unsuitable for monitoring); culture (allows antibiotic-sensitivity testing, expensive, not widely available, low sensitivity); histology (can detect early MALT lymphoma change, expensive but highly sensitive/ specific). All are less accurate if the patient has had antibiotics in the past 4 weeks or a PPI in the past 2 weeks.

Eradication therapy

First-line: PPI-based triple therapy — now 14 days, not 7

For 14 days, use:

• Esomeprazole 20mg twice daily, plus
• Amoxicillin 1g twice daily, plus
• Clarithromycin 500mg twice daily

(Available as a combination pack, Nexium Hp7 — but this only covers 7 days, so write 2 prescriptions to cover the full 14 days. Any equivalent-dose PPI can substitute for esomeprazole: lansoprazole 30mg, omeprazole 20mg, pantoprazole 40mg, or rabeprazole 20mg, all twice daily.)

Why 14 days, not the 7 days some guidelines still list: extending treatment to 14 days significantly increases the eradication rate over a 7-day course. 7-day success rates are now considered too low. Monitor INR in patients on warfarin (clarithromycin interaction).

Penicillin hypersensitivity: replace amoxicillin with metronidazole 400mg twice daily (same 14-day duration, same PPI + clarithromycin backbone). Note metronidazole-resistant H. pylori is common in Australia (~50%), so this combination is markedly less reliable than the amoxicillin-based regimen — confirm the patient has a true IgE-mediated (immediate) hypersensitivity before defaulting to it, since the first-line regimen is much more effective if penicillin can be used safely.

Antibiotic resistance

Clarithromycin resistance has risen significantly in Australia over the past two decades and, together with poor treatment adherence, is now the primary cause of eradication failure. Patients with refractory H. pylori should avoid repeat treatment with first-line clarithromycin-based triple therapy — success rates on a second attempt are low (historically cited as ~10%).

Side effects (main driver of poor adherence — counsel proactively)

PPI: headache, nausea, vomiting, diarrhoea, abdominal pain, constipation, flatulence. Clarithromycin: taste disturbance. Amoxicillin: rash, diarrhoea. Metronidazole: nausea, headache, anorexia, abdominal pain, vomiting, diarrhoea, metallic taste. Bismuth salts: dark discolouration of stool/tongue/teeth. Tetracycline: photosensitivity, GI upset. Levofloxacin: diarrhoea, headache, nausea.

Salvage therapy (first-line treatment failure)

Avoid repeating clarithromycin-based triple therapy. After confirming adherence to the first course:

Quinolone-based triple therapy (can be GP-initiated, levofloxacin needs Special Access Scheme [SAS] approval) — for 10 days: a PPI twice daily (esomeprazole 20mg, lansoprazole 30mg, omeprazole 20mg, pantoprazole 40mg, or rabeprazole 20mg) plus amoxicillin 1g twice daily plus levofloxacin 250mg twice daily (or 500mg once daily) or moxifloxacin 400mg once daily.

Otherwise refer to a GP with special interest, gastroenterologist, or infectious diseases physician for salvage therapy — options include levofloxacin- or rifabutin-based triple therapy, or colloidal-bismuth-subcitrate-based quadruple therapy (PPI + bismuth + tetracycline + metronidazole for 7–14 days), available via SAS or the Highly Specialised Drug Scheme (S100). Culture and susceptibility testing may be arranged after first-line failure to identify the minority with metronidazole-susceptible H. pylori.

Children

PPI twice daily + amoxicillin twice daily + clarithromycin twice daily for 7 days (replace amoxicillin with metronidazole twice daily if penicillin-hypersensitive).

Follow-up and referral

• Test-of-cure: repeat UBT ≥4 weeks after completing therapy (same PPI washout as before initial testing). Serology is not useful here.
• If eradication fails and non-compliance is the cause, simply repeat first-line therapy.
• If eradication fails despite good compliance, arrange non-urgent gastroenterology referral (can take months — flag any red flags/significant symptoms for prompt triage) or an infectious diseases referral if asymptomatic or already under gastroenterology review for the underlying condition.
• Urgent gastroenterology referral for any red flag at presentation.