Campylobacter jejuni

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C. jejuni - The Gutsy Glider

Campylobacter jejuni Gram Stain: Curved, S-shaped Rods

  • Gram-negative, motile, curved (S-shaped or “gull-wing”) rod; oxidase ⊕.
  • Thrives in heat (thermophilic) at 42°C and low oxygen (microaerophilic).
  • Source: Undercooked poultry, unpasteurized milk, pets (puppies).
  • Clinical: Common cause of invasive, inflammatory, bloody diarrhea.

Guillain-Barré Syndrome (GBS): Ascending paralysis triggered by autoimmune cross-reactivity with lipooligosaccharides. A major post-infectious sequela.

Pathogenesis - Invasion Games

  • Adhesion & Motility: Utilizes adhesin protein CadF to bind to fibronectin and polar flagella for corkscrew motility to penetrate intestinal mucus.
  • Invasion: Invades enterocytes in the jejunum, ileum, and colon via endocytosis, surviving within vacuoles.
  • Toxin-Mediated Damage: Releases Cytolethal Distending Toxin (CDT), an A-B toxin.
    • CDT's B subunit binds to the cell.
    • CDT's A subunit (CdtB) acts as a DNase, causing dsDNA breaks, leading to cell cycle arrest in G2/M phase and apoptosis.

C. jejuni virulence factors and inhibition mechanisms

Molecular Mimicry: C. jejuni's lipooligosaccharide (LOS) can mimic human gangliosides (e.g., GM1), triggering autoimmune cross-reactivity that leads to Guillain-Barré syndrome (GBS).

Clinical Features - Gut Punch & Nerve Pinch

  • Gastroenteritis (Acute Enteritis):

    • Incubation: 1-3 days.
    • Prodrome: Fever, headache, myalgias.
    • Main symptoms: Severe, crampy abdominal pain (can mimic appendicitis) followed by profuse, watery, and frequently bloody diarrhea (≥10 stools/day).
    • Usually self-limiting within one week.
  • Post-Infectious Sequelae (1-3 weeks post-infection):

    Campylobacter jejuni is the most common infectious precipitant of Guillain-Barré syndrome (GBS). The mechanism involves molecular mimicry between bacterial lipooligosaccharides and peripheral nerve gangliosides (anti-GM1 antibodies).

    • Guillain-Barré Syndrome: Acute, ascending, symmetric flaccid paralysis with ↓ or absent deep tendon reflexes (areflexia).
    • Reactive Arthritis: Asymmetric oligoarthritis, urethritis, conjunctivitis. Strong HLA-B27 association. 📌 "Can't see, can't pee, can't climb a tree."

Guillain-Barré Syndrome (GBS) Overview

Diagnosis & Treatment - Lab Hunt & Drug War

  • Lab Diagnosis
    • Stool Culture: Gold standard, requires special conditions.
      • Grows at 42°C (thermophilic).
      • Microaerophilic (↑CO₂, ↓O₂).
      • Media: Skirrow's agar, Campy BAP.
    • Microscopy: Gram-negative, motile, S-shaped or "gull-wing" rods.
    • Biochemical: Oxidase-positive.
  • Treatment
    • Mainstay: Supportive care (rehydration).
    • Severe Disease: Macrolides (e.g., Azithromycin).
    • ⚠️ High rates of fluoroquinolone resistance.

Campylobacter jejuni is the most common infectious antecedent to Guillain-Barré syndrome (GBS).

High‑Yield Points - ⚡ Biggest Takeaways

  • Most common bacterial cause of gastroenteritis in developed countries, frequently from undercooked poultry.
  • A curved, Gram-negative rod that is oxidase-positive and thrives at 42°C (thermophilic).
  • Presents with fever, cramping abdominal pain, and inflammatory bloody diarrhea.
  • Strongly associated with post-infectious Guillain-Barré syndrome (GBS) due to molecular mimicry.
  • Can also lead to reactive arthritis as a long-term complication.
  • Usually self-limited; macrolides are reserved for severe or prolonged illness.

Practice Questions: Campylobacter jejuni

Test your understanding with these related questions

A 16-year-old male with no significant past medical, surgical, or family history presents to his pediatrician with new symptoms following a recent camping trip. He notes that he went with a group of friends and 1 other group member is experiencing similar symptoms. Over the past 5 days, he endorses significant flatulence, nausea, and greasy, foul-smelling diarrhea. He denies tenesmus, urgency, and bloody diarrhea. The blood pressure is 118/74 mm Hg, heart rate is 88/min, respiratory rate is 14/min, and temperature is 37.0°C (98.6°F). Physical examination is notable for mild, diffuse abdominal tenderness. He has no blood in the rectal vault. What is the patient most likely to report about his camping activities?

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Flashcards: Campylobacter jejuni

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What is the shape and stain of Campylobacter jejuni?_____

TAP TO REVEAL ANSWER

What is the shape and stain of Campylobacter jejuni?_____

Gram negative curved rod

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