What is Campylobacter species?

Campylobacter Species: A Leading Cause of Bacterial Gastroenteritis

Campylobacter species are gram-negative bacteria that represent one of the most important causes of foodborne bacterial gastroenteritis worldwide, with C. jejuni and C. coli being the predominant pathogenic species in humans. 1, 2

Microbiology and Classification

• Campylobacter are curved, spiral, or S-shaped gram-negative rods
• The genus includes multiple species with varying clinical significance:
  • C. jejuni and C. coli: Most common causes of human gastroenteritis
  • C. fetus: Associated with systemic infections, particularly in immunocompromised hosts
  • Other emerging species: C. upsaliensis, C. lari, C. concisus, and enterohepatic Helicobacter species (H. cineadi and H. fennelliae) 3, 4

Clinical Manifestations

Campylobacter infections can present in three main patterns:

1. Self-limited gastroenteritis - Most common presentation

   • Watery diarrhea, abdominal pain, fever
   • May progress to bloody diarrhea (less common than with Shigella but does occur)

2. Severe and prolonged diarrheal disease

   • Associated with fever, bloody diarrhea, and weight loss
   • Potential for bacteremia, especially in immunocompromised patients

3. Septicemia with extra-intestinal involvement

   • Can occur with or without preceding gastrointestinal illness
   • More common in immunocompromised hosts 3

Post-infectious Complications

• Reactive arthritis
• Guillain-Barré syndrome (autoimmune neuropathy)
• Post-infectious irritable bowel syndrome (PI-IBS) - occurs in approximately 10% of cases 3, 2

Diagnosis

The CDC defines a confirmed case of Campylobacter infection as:

• Isolation of Campylobacter from any clinical specimen 3

Diagnostic approaches include:

• Stool culture: Gold standard for diagnosis

  • Special culture conditions required (microaerophilic environment)
  • Standard stool cultures may fail to identify non-jejuni/non-coli species

• Blood cultures: Should be obtained in patients with diarrhea and fever due to risk of bacteremia, particularly in immunocompromised patients

• Molecular diagnostic panels: Can detect Campylobacter DNA but may not distinguish viable from non-viable organisms 3, 5

Treatment

Azithromycin is the preferred first-line antibiotic for treating severe Campylobacter infections due to high fluoroquinolone resistance rates worldwide. 5

Treatment recommendations:

• Azithromycin: 1000 mg as a single dose or 500 mg daily for 3 days for adults; 30 mg/kg as a single dose for children
• Alternative antibiotics (if local susceptibility patterns confirm effectiveness):
  • Ciprofloxacin: 750 mg single dose or 500 mg twice daily for 3 days
  • Levofloxacin: 500 mg once daily for 3 days

Antimicrobial Resistance Concerns

• Fluoroquinolone resistance is widespread:
  • Up to 89.8% resistance in C. jejuni in some regions
  • 60% of travel-related Campylobacter infections are fluoroquinolone-resistant
• Macrolide (azithromycin) resistance is emerging but still limited (4-15% depending on region) 3, 5

Supportive Care

• Oral rehydration with reduced osmolarity solution
• IV fluids for severe dehydration
• Loperamide may be used with antibiotics (4 mg first dose, then 2 mg after each loose stool, maximum 16 mg/24 hours)
• Avoid antimotility agents in patients with high fever or bloody diarrhea 5

Prevention

Key preventive measures include:

• Hand hygiene: Thorough handwashing after potential contact with feces, handling pets or animals, gardening, and before food preparation
• Food safety:
  • Avoid raw or undercooked poultry, meat, and seafood
  • Avoid unpasteurized dairy products and fruit juices
  • Cook poultry to internal temperature of 180°F (82°C) and red meats to 165°F (74°C)
• Safe sexual practices: Avoid unprotected sex practices that might result in oral exposure to feces 3, 5

Special Considerations

Immunocompromised Patients

• Higher risk for severe, prolonged illness and bacteremia
• Lower threshold for antibiotic treatment
• May require chronic suppressive therapy for recurrent infections 3, 5

Travel-Associated Infections

• International travel is associated with higher risk of resistant Campylobacter
• Particularly high resistance rates in Southeast Asia, Mexico, and South America
• Consider travel history when selecting empiric antibiotics 3, 5

Public Health Importance

Campylobacter represents a significant public health challenge requiring a "One Health" approach that recognizes the interconnection between human, animal, and environmental health. Complete elimination from the food chain is not currently feasible, but combined intervention strategies along with consumer education can help reduce the burden of disease 1, 2.