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Bacterium

Campylobacter jejuni

Common name: C. jejuni

Harmful Digestive Gut
Harmful
Effect
Digestive
Impact
Gut
Location
Common
Prevalence
Last reviewed: January 14, 2024

Leading cause of bacterial gastroenteritis worldwide

Prevalence: Most common bacterial cause of diarrheal disease globally

Interacts with: Bacteroides vulgatus, Escherichia coli, Lactobacillus species, Bifidobacterium species

Overview

Scientifically accurate microscopy-style illustration of Campylobacter jejuni showing its characteristic gram-negative spiral or S-shaped bacterium with a single polar flagellum

Campylobacter jejuni is the world's leading cause of bacterial gastroenteritis, responsible for approximately 90% of campylobacteriosis cases.[1] The Global Burden of Disease Study 2021 estimated 135 million cases (95% CI: 106-175 million), 38,000 deaths (95% CI: 24,100-60,100), and 3.29 million disability-adjusted life years annually. Children under 5 years account for 48% of all deaths, with the highest incidence in Sub-Saharan Africa (2,730-3,090 per 100,000).

Characteristics

C. jejuni is a gram-negative, microaerophilic, spiral-shaped bacterium with distinctive features:

  • Motility: Highly motile via polar flagella (FlaA/FlaB) essential for colonization
  • Growth requirements: Microaerophilic (3-5% O2), capnophilic; optimal growth at 42°C
  • Metabolism: Asaccharolytic, relying on amino acids (L-serine, L-aspartate, L-glutamate) and Krebs cycle intermediates
  • Infectious dose: Extremely low—as few as 50-800 organisms can cause infection
  • Virulence genes: Nearly all strains carry cdtB (100%), cadF (100%), flgE2 (100%), iamA (99%), ciaB (87%)

Pathogenesis Mechanisms

Adhesion and Invasion

C. jejuni employs multiple adhesins to attach to and invade intestinal epithelial cells:[2]

  • CadF: 37 kDa adhesin binding fibronectin; influences microfilament organization
  • JlpA: Surface lipoprotein interacting with host HSP90β
  • FlpA: Fibronectin-like protein required for maximal adherence
  • Peb1: Periplasmic binding protein facilitating epithelial adhesion

Invasion occurs via a unique trigger mechanism:

  1. HtrA serine protease cleaves tight junction proteins (occludin, claudin-8, E-cadherin)
  2. Paracellular transmigration allows bacteria to reach the basolateral surface
  3. Subvasion: Invasion from below via Rac1 activation and focal adhesion kinase phosphorylation
  4. Flagellar Type III Secretion System (T3SS) delivers effectors (CiaB, CiaC, CiaD) promoting invasion
  5. Formation of Campylobacter-containing vacuole (CCV) that avoids lysosomal fusion

Cytolethal Distending Toxin (CDT)

CDT is a tripartite AB₂ genotoxin causing DNA damage and cell cycle arrest:[3]

Subunit Function
CdtA Binding subunit; recognizes cholesterol-rich lipid rafts via CRAC-like motif
CdtB Active enzymatic subunit with DNase I-like activity; causes DNA double-strand breaks
CdtC Binding subunit; contains cholesterol recognition motif (LPFGYVQFTNPK)

Mechanism of action:

  1. CdtA/CdtC bind to membrane cholesterol-rich microdomains
  2. Internalization via clathrin-dependent endocytosis
  3. CdtB retrograde trafficking through trans-Golgi to ER
  4. Nuclear translocation via nuclear localization signal
  5. DNA double-strand breaks → G2/M cell cycle arrest → cell distension/apoptosis

CDT also induces IL-8 production promoting leukocyte chemotaxis and activates NOD1/NOD2-dependent NF-κB signaling.

Guillain-Barré Syndrome Association

C. jejuni infection is the most common trigger of Guillain-Barré syndrome (GBS), identified in 25-50% of cases.[4]

Molecular Mimicry Mechanism

C. jejuni lipooligosaccharide (LOS) contains N-acetylneuraminic acid structures that mimic human peripheral nerve gangliosides:

Ganglioside Location Associated GBS Variant Antibodies
GM1 Motor axonal membranes, nodes of Ranvier AMAN Anti-GM1 IgG
GD1a Motor axonal membranes AMAN/AMSAN Anti-GD1a IgG
GQ1b Cranial nerves Miller Fisher syndrome Anti-GQ1b IgG

Pathogenic cascade:[5]

  1. Infection triggers IgG1/IgG3 antibodies against LOS structures
  2. Cross-reactive antibodies bind peripheral nerve gangliosides
  3. Complement activation and membrane attack complex formation
  4. Macrophage recruitment to periaxonal space
  5. Disappearance of voltage-gated sodium channels
  6. Axonal degeneration or conduction block

Risk factors include:

  • 77-100 fold increased GBS risk following C. jejuni infection
  • Incidence: 0.07% of infections develop GBS (1 in 1,000)
  • Onset: 10 days to 3 weeks after diarrhea
  • LOS biosynthesis class A and B strains strongly correlated with AMAN

Antimicrobial Resistance

C. jejuni exhibits alarming and rising antimicrobial resistance, classified as a WHO high-priority pathogen.[6]

Global Resistance Patterns

Antibiotic China Iran Jordan US Trend
Ciprofloxacin 83.5% 67% 46.6% 24.5% → 29.7%
Tetracycline 83.2% 60% 55.1% -
Erythromycin 0% (human) 14% 9.3% Low
Gentamicin - 6% 4.2% Low

Resistance mechanisms:

  • Efflux pumps: cmeABC (74.7%), RE-cmeABC (71.3%)
  • Target mutations: gyrA T86I (94.8% in resistant strains)
  • Ribosomal protection: tet(O) in all tetracycline-resistant strains
  • Multidrug resistance: 72.8% in China; 36.4% in Jordan

Poultry Reservoir and Food Safety

Poultry, especially chickens, are the primary reservoir and account for 50-80% of human cases.[7]

Colonization Characteristics

  • Commensal in chickens (no clinical disease)
  • Colonization begins at 2-3 weeks of age
  • Spreads to entire flock within days
  • Levels: 10⁶-10¹⁰ CFU/g feces
  • Up to 70% of European broiler batches colonized

Intervention Effectiveness

Intervention Reduction
Fly screens Positive flocks: 51.4% → 15.4%
Bacteriophages (CP8, CP34) 3.2 log₁₀ at slaughter
Probiotics (PoultryStar) ≥6 log₁₀ CFU/g
Bacteriocins (OR-7) >6 log₁₀ (million-fold)
Organic acids (formic acid + sorbate) Complete elimination
2% lactic acid on carcasses 37-56% human risk reduction
Freezing (2-3 days) 62-93% risk reduction

Key finding: A 2 log₁₀ reduction on broiler carcasses equals a 30-fold decrease in human infection risk.

Post-Infectious Sequelae

Beyond acute gastroenteritis, C. jejuni causes significant chronic complications:[8]

Sequela Prevalence Risk Factors
Irritable bowel syndrome 4.48% Unknown
Reactive arthritis 1.72% HLA-B27, male sex (3:1 ratio)
Ulcerative colitis 0.35% IL23R/IL10 SNPs
Crohn's disease 0.22% Genetic susceptibility
Guillain-Barré syndrome 0.07% LOS class A/B strains

Reactive arthritis typically presents within 2-4 weeks, affecting primarily knees and ankles, with duration of 3-12 months.

Microbiome Interactions

The intestinal microbiota provides crucial colonization resistance against C. jejuni:[9]

Protective Mechanisms

  • Secondary bile acids: Deoxycholate (DCA) inhibits mTOR signaling and reduces colitis
  • Clostridium XIVa: Enhances anti-inflammatory signaling; directs Treg expansion producing IL-10
  • Bifidobacterium: Enriched in resistant hosts; biotransforms bile acids; downregulates flaA
  • Lactobacillus: Inhibits growth via organic acid production and acidification

Colonization Factors

  • Chemotaxis: CheA/CheY system navigates toward amino acids and favorable growth conditions
  • Metabolic requirements: L-serine, L-aspartate, fumarate, pyruvate as primary substrates
  • Iron acquisition: FeoB, Fur, CfrA, CfrB systems essential for colonization
  • Phase variation: Capsular polysaccharide variation for host adaptation

Vaccine Development

No commercial vaccine exists, but multiple approaches show promise:[10]

Clinical Trials

  • CJCV2 (NCT05500417): Phase 1 conjugate vaccine (capsule-CRM197 with ALFQ adjuvant); completed January 2025
  • H2O2-inactivated vaccine: 83% protection in rhesus macaques (P=0.048); anti-flagellin titers of 92,042

Challenges

  • Short 6-week broiler lifespan requires rapid immune response
  • Antigenic diversity across strains and serotypes
  • Safety concerns regarding ganglioside-mimicking structures
  • Previous flagellin-based vaccines showed suboptimal clinical protection

One Health Approach

Effective C. jejuni control requires integrated surveillance across human, animal, and environmental sectors:[11]

Transmission Dynamics

  • Poultry: Primary reservoir (50-80% attribution)
  • Cattle: Secondary reservoir via raw milk and meat
  • Wildlife: Amplifying hosts in anthropogenic landscapes
  • Water: Surface water contamination facilitates transmission
  • Climate change: Flooding and warming increase transmission risk

Surveillance Strategies

  • Whole genome sequencing enables outbreak source identification
  • Core genome MLST tracks clonal complexes across human-animal interface
  • Oxford Nanopore Technologies provides comprehensive genomic analysis
  • Multi-sectoral collaboration essential for effective control

Related Organisms

B
Bacillus cereus Digestive
B
Bacillus coagulans Digestive
B
Bacillus subtilis Digestive
B
Bacteroides dorei Digestive
B
Bacteroides fragilis Digestive
B
Bacteroides thetaiotaomicron Digestive

Frequently Asked Questions

What is Campylobacter jejuni?

Campylobacter jejuni is a bacterium found in the human microbiome.

Where is Campylobacter jejuni found in the body?

Campylobacter jejuni is primarily found in the Gut.

What are the health impacts of Campylobacter jejuni?

Campylobacter jejuni primarily impacts Digestive and is potentially harmful for human health.

Research References

  1. GBD 2021 Collaborators. Global, regional, and national burden of Campylobacter enteritis as a cause of diarrhoeal diseases, 1990–2021. EClinicalMedicine. 2024. doi:10.1016/j.eclinm.2024.102830 ↩
  2. Kemper L, Hensel A. Campylobacter jejuni: targeting host cells, adhesion, invasion, and survival. Applied Microbiology and Biotechnology. 2023. doi:10.1007/s00253-023-12456-w ↩
  3. Lai CK, Chen YA, Lin CJ, et al.. Molecular Mechanisms and Potential Clinical Applications of Campylobacter jejuni Cytolethal Distending Toxin. Frontiers in Cellular and Infection Microbiology. 2016. doi:10.3389/fcimb.2016.00009 ↩
  4. Yuki N, Susuki K, Koga M, et al.. Carbohydrate mimicry between human ganglioside GM1 and Campylobacter jejuni lipooligosaccharide causes Guillain-Barré syndrome. Proceedings of the National Academy of Sciences. 2004. doi:10.1073/pnas.0402391101 ↩
  5. Leonhard SE, Papri N, Querol L, et al.. Campylobacter jejuni Infection, Anti-Ganglioside Antibodies, and Neuropathy. Microorganisms. 2022. doi:10.3390/microorganisms10112139 ↩
  6. Li Z, Cai H, Xu B, et al.. Prevalence, antibiotic resistance, and virulence determinants of Campylobacter jejuni in China: A systematic review and meta-analysis. One Health. 2025. doi:10.1016/j.onehlt.2025.100990 ↩
  7. Taha-Abdelaziz K, Singh M, Sharif S, et al.. Intervention Strategies to Control Campylobacter at Different Stages of the Food Chain. Microorganisms. 2023. doi:10.3390/microorganisms11010113 ↩
  8. Shafiee D, Salpynov Z, Gusmanov A, et al.. Enteric Infection-Associated Reactive Arthritis: A Systematic Review and Meta-Analysis. Journal of Clinical Medicine. 2024. doi:10.3390/jcm13123433 ↩
  9. Sun X, Winglee K, Gharaibeh RZ, et al.. Microbiota-derived Metabolic Factors Reduce Campylobacteriosis in Mice. Gastroenterology. 2018. doi:10.1053/j.gastro.2018.01.042 ↩
  10. Quintel BK, Prongay K, Lewis AD, et al.. Vaccine-mediated protection against Campylobacter-associated enteric disease. Science Advances. 2020. doi:10.1126/sciadv.aba4511 ↩
  11. Njoga EO, Nnaemeka VC, Jaja IF, et al.. Systematic review and meta-analysis of Campylobacter species infections in humans and food-producing animals in Nigeria: The imperative of a One Health control approach. One Health. 2025. doi:10.1016/j.onehlt.2025.101029 ↩