Campylobacter jejuni
🐔 Campylobacter infection is a zoonotic cause of bacterial gastroenteritis, often linked to undercooked poultry, meat, or contaminated milk.
It is one of the commonest causes of bacterial diarrhoea worldwide and can lead to serious complications such as Guillain-Barré syndrome.
📖 About
- Zoonotic infection causing acute bacterial diarrhoea.
- Common sources: undercooked chicken, meat, contaminated milk, and occasionally untreated water.
- Complications: Guillain-Barré syndrome (autoimmune neuropathy), Reactive arthritis, and bacteraemia in immunocompromised patients.
🧬 Characteristics
- Gram-negative curved bacillus – classic “seagull wings” appearance under the microscope.
- Motile via a single polar flagellum 🏊.
- Capsulated, non–spore-forming.
- Optimal growth at 42°C under microaerophilic conditions (5–10% O₂, 10% CO₂).
🔎 Types
- Campylobacter jejuni – most common cause in humans.
- Campylobacter coli – also causes diarrhoea but less common.
- Campylobacter fetus – tends to affect immunocompromised patients, often causing systemic infection.
🦠 Aetiology & Pathogenesis
- Virulence factors: lipopolysaccharide endotoxin, cytotoxins, and ability to invade the intestinal mucosa.
- Reservoir: wild birds, poultry, domestic animals 🐓🐄🐕.
- Transmission: ingestion of undercooked poultry, unpasteurised milk, contaminated water, or cross-contamination in kitchens.
🤒 Clinical Features
- Incubation: 2–5 days after ingestion.
- Typical illness: acute colitis with colicky abdominal pain, fever, malaise, diarrhoea often with blood and pus.
- Severe cases: dehydration, septicaemia (esp. immunocompromised).
- Post-infectious complications:
- Guillain-Barré syndrome (autoimmune demyelinating neuropathy).
- Reactive arthritis (HLA-B27 association).
🧪 Investigations
- Stool culture – grows on selective charcoal agar at 42°C under microaerophilic conditions.
- Characteristic grey colonies.
- Oxidase + and Catalase +.
- Blood cultures in suspected bacteraemia.
💊 Management
- 👉 Supportive therapy: Oral/IV rehydration, electrolyte replacement.
- Most cases are self-limiting within 2–5 days.
- Antibiotics reserved for:
- Severe or prolonged disease
- Immunocompromised patients
- Extra-intestinal complications
- First-line: Macrolides (e.g. Erythromycin, Azithromycin).
- Alternative: Fluoroquinolones (e.g. Ciprofloxacin) – but resistance is increasingly common ❗.
📚 Key Notes for Exams & Practice
- Think Campylobacter in a patient with bloody diarrhoea after chicken consumption.
- Complication to always mention: Guillain-Barré syndrome.
- Differentiate from Salmonella/Shigella by history + stool culture.
