Microbiology · MU Sofia

80. Genus Campylobacter

Covers the morphology, microaerophilic and thermophilic growth requirements and common species of Campylobacter, then its virulence factors such as flagellar motility, adhesins and cytolethal distending toxin. It goes on to epidemiology and transmission, clinical forms including gastroenteritis and Guillain-Barré syndrome, laboratory diagnosis with a summary table of methods, treatment with first-line antibiotic choices, and prevention.

Inside: 9 sections · 8 labelled pictures · 3 tables · 13 flashcards · 4 min

Topic 80 of 113 in the MU Sofia syllabus for Microbiology (Medicine, Year 3). The free AceMed note covers it in 9 sections, about 373 words (4 min of reading), with 13 flashcards.

In this note

  1. Genus Campylobacter
  2. I. General Characteristics
  3. II. Morphology and Structural Features
  4. III. Virulence Factors
  5. IV. Epidemiology
  6. V. Clinical Manifestations
  7. VI. Laboratory Diagnosis
  8. VII. Treatment
  9. VIII. Prevention

I. General Characteristics

  • Gram-negative, curved spiral-shaped rods ("gull-wing" appearance).
  • Motile due to a single polar flagellum.
  • Microaerophilic: Requires 5–10% oxygen and 3–10% CO₂ for growth.
  • Oxidase-positive, catalase-positive (especially C. jejuni).
  • Thermophilic: Optimum growth at 42°C (avian body temperature).
  • Grows on selective media such as Campy-BAP under specific atmospheric conditions.
  • Common species:
  • C. jejuni – most common human pathogen.
  • C. coli, C. fetus, C. upsaliensis.

II. Morphology and Structural Features

  • Not well stained with Gram stain; curved appearance may be missed on routine staining.
  • Darting motility on wet prep is characteristic and aids in presumptive identification.

III. Virulence Factors

  • Flagellar motility: Penetration through intestinal mucus.
  • Adhesins: Mediate attachment to intestinal epithelial cells.
  • Cytolethal Distending Toxin (CDT): Causes DNA damage and apoptosis → inflammatory diarrhea.
  • Invasiveness: Invades epithelial cells → inflammatory response, ulceration.
  • LPS (Endotoxin): Contributes to immune activation and local inflammation.
  • Immune evasion: Phase variation of surface antigens aids in avoiding host defenses.

IV. Epidemiology

  • Reservoirs: Commonly found in intestines of poultry, livestock, domestic pets, birds, and wild animals.
  • Transmission:
  • Ingestion of undercooked poultry, unpasteurized milk, or contaminated water.
  • Fecal-oral route, especially in areas with poor sanitation.
  • High-risk groups:
  • Children under 5
  • Travelers
  • Immunocompromised patients
  • Seasonal variation: Increased cases in summer months.
  • Infectious dose: Very low (as few as 500 organisms).

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