Microbiology · Other Gram-negative rods
Campylobacter jejuni !
- Bacterium
- Gram-negative
- Contact
- Exam priority: medium
A bacterium from undercooked chicken that causes diarrhea, often bloody; rarely it is followed by paralysis (Guillain-Barré).
Updated 2026-11-01
At a glance
- Gram
- Gram-negative
- Shape
- Curved comma, S or "seagull wing" rod
- Oxygen
- Microaerophilic
- Family
- Campylobacteraceae
- Stain
- Gram: curved red rods
Morphology
- Curved Gram-negative rod with a polar flagellum
- Oxidase-positive
- Grows best at 42 °C on selective media (Campy or Skirrow agar) with low oxygen
Transmission
- Undercooked chicken and other meats, kitchen cross-contamination
- Raw milk, contaminated water or ice
- Contact with animals and pets
- Contact (on top of standard) for diapered or incontinent patients
Reservoir: Poultry and other warm-blooded animals (cattle, pigs, sheep, pets)
Isolation precautions
What the care team adds to standard precautions.
- Contact
- Gown and gloves; dedicated equipment. For C. difficile, soap-and-water hand washing.
Virulence factors
- Flagellum and spiral shape: cross the intestinal mucus
- Invades the mucosa of the jejunum, ileum and colon
- Lipooligosaccharide that resembles nerve gangliosides: molecular mimicry that triggers Guillain-Barré
Diseases it causes
- Acute gastroenteritis (Campylobacter enteritis) Acute (viral) gastroenteritis →
- Guillain-Barré syndrome weeks after the diarrhea Guillain-Barré syndrome →
Clinical picture
- Onset 2 to 5 days after exposure
- Fever, strong abdominal pain and diarrhea, bloody in many cases
- Can mimic appendicitis
- Other complications: reactive arthritis
Diagnosis
- Stool culture on selective media at 42 °C under microaerophilic conditions
- Stool Gram stain: curved "seagull wing" rods
- Stool PCR panels
Treatment
Rehydration and electrolytes; most cases resolve alone. Antibiotics are used in severe, invasive or immunosuppressed cases, with a macrolide (azithromycin) preferred because fluoroquinolone resistance is high.
Drug class only; doses and regimens are set by the clinician from the current guideline.
In Pharmacology:
Prevention
- Cook chicken through and avoid cross-contamination
- Pasteurized milk and safe water
- Handwashing after touching raw meat or animals
Test yourself
Think of the answer, then tap the question to see it.
Which food is the classic source of Campylobacter jejuni?
Undercooked chicken (and raw milk).
Which neurological complication is linked to prior Campylobacter infection?
Guillain-Barré syndrome, through molecular mimicry with nerve gangliosides.
At what temperature and oxygen level is Campylobacter cultured?
At 42 °C under microaerophilic conditions, on selective media.
Which antibiotic is preferred for severe infection, and why?
A macrolide such as azithromycin, because fluoroquinolone resistance is high.
Related
Related conditions
← Back to the group: Other Gram-negative rods
Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Campylobacter (WHO, 2020); Fichas y Protocolos (Instituto Nacional de Salud (INS), Colombia, 2026).
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Representative model, for educational purposes only.