Helicobacter pylori
Diagnosis
- Non-invasive: stool antigen, H. pylori IgG, urease breath test
- Invasive (biopsy): histology, culture, PCR
Treatment Recommendations:
- Treat all H. pylori positive patients
- Confirm eradication ≥4 weeks after treatment
- Base regimen on resistance patterns and exposure history
Triple Therapy (Initial Regimen – No Clarithromycin Exposure)
Treat for 14 days
Non-Bismuth Quadruple Therapy (Alternative Initial Regimen)
Same as above, but include both Amoxicillin AND Metronidazole AND Clarithromycin
Bismuth Quadruple Therapy (2nd-line or alternative for allergy)
- PPI + Bismuth 240 mg + Tetracycline OR Doxycycline + Metronidazole
- PO 12-hourly, 14 days
Fluoroquinolone Triple Therapy (for failed regimens)
- PPI + Amoxicillin or Metronidazole + Levofloxacin 500 mg PO 12-hourly × 14 days
C. difficile Infection (CDI)
Key Points:
- Caused by broad-spectrum antibiotics
- Treat only symptomatic patients
- Always stop inciting antibiotic
Mild to Moderate Disease:
Treat 10–14 days
Severe Disease:
- Vancomycin 125 mg PO 6-hourly (adults)
- 40 mg/kg/day PO ÷ q6h (children)
- Increase to 500 mg PO q6h if no improvement
Fulminant or Critically Ill:
- Vancomycin 500 mg PO q6h
- PLUS Metronidazole 500 mg IV q6h
Salvage Therapy:
- Tigecycline 100 mg IV load, then 50 mg IV 12-hourly × 10–14 days
Treatment Failures:
- Repeat vancomycin or tapering doses
- Faecal transplant or fidaxomicin for recurrence (if available)
Salmonella
NTS – Intestinal (usually self-limiting)
Antibiotics for high-risk patients only:
Duration: 7–14 days
NTS – Extra-intestinal:
- Ceftriaxone, Cefotaxime, or Levofloxacin IV × 14 days
Typhoid Fever
- Ciprofloxacin or Levofloxacin OR Ceftriaxone (avoid quinolones if acquired in Asia)
- Add dexamethasone for severe disease
Shigella (Shigellosis)
- Empiric oral therapy: Ciprofloxacin or Azithromycin
- IV therapy: Ceftriaxone 1–2 g daily (adults), 50 mg/kg (children)
- Duration: 3–10 days depending on severity
Campylobacter
- Self-limiting; treat if severe, prolonged, or in immunocompromised
E. coli Diarrhoea
- ETEC: treat travellers' diarrhoea (Ciprofloxacin or Azithromycin × 3 days)
- EHEC: avoid antibiotics (↑HUS risk)
- EAEC: Ciprofloxacin × 3 days
- EIEC: treat as Shigella
Cholera
- Doxycycline 300 mg PO once OR
- Azithromycin 1 g PO once
- Rehydration is key
Yersinia
- Only treat severe/systemic cases
Viral Gastroenteritis
- Self-limiting; no antibiotics
- Supportive care: fluids, antiemetics (adults), probiotics
- Avoid anti-motility in children
Amoebiasis (E. histolytica)
Mild to Moderate:
- Metronidazole OR Tinidazole × 7–10 days
- Follow with luminal agents to clear cysts (Paromomycin or Diloxanide)
Giardiasis
- Metronidazole OR Tinidazole OR Albendazole
- Recurrent cases: consider longer course or switch class
Cryptosporidiosis
- Self-limiting in healthy hosts
- Treat immunocompromised with:
- ART (for HIV), plus supportive care
- ± Nitazoxanide, Paromomycin, Azithromycin
Blastocystis hominis
- Often incidental; treat only if symptomatic and no other pathogen found
- Metronidazole or Cotrimoxazole
Intra-Abdominal Infections (IAI)
Community-acquired:
- Low-risk: Amox-clav, Ertapenem, or Ceftriaxone + Metronidazole
- High-risk: Meropenem or Pip-tazo OR Cefepime + Metronidazole
Healthcare-associated:
- Empiric therapy: Meropenem, Imipenem, Pip-tazo
- Add Vancomycin for MRSA
- Add antifungal if Candida is isolated
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