Campylobacter jejuni
One-Sentence Definition
Campylobacter jejuni is a thermophilic, microaerophilic curved Gram-negative bacillus and a leading cause of bacterial foodborne gastroenteritis worldwide, with rare but important post-infectious Guillain–Barré syndrome.
Taxonomy & Morphology
- Campylobacterales; spiral/S-shaped; darting motility
- Grows best ~42 °C, microaerobic atmosphere — selective Campy media
- Related: C. coli (also common in human diarrhea); Helicobacter is a related genus
Virulence Highlights
- Invasion and cytolethal distending toxin (CDT) in many strains
- Flagellar motility critical for colonization
- Molecular mimicry of LOS with peripheral-nerve gangliosides → autoimmune GBS risk
- High genomic plasticity; phase variation of surface structures
Clinical Syndromes
- Acute inflammatory diarrhea (often bloody), abdominal pain, fever
- Self-limited in immunocompetent hosts; bacteremia uncommon
- Post-infectious: Guillain–Barré syndrome; reactive arthritis
- Poultry is the dominant reservoir (One Health)
Diagnosis
- Stool culture on selective media at 42 °C; antigen or PCR / GI syndromic panels
- Blood culture if invasive disease suspected
- Species ID: jejuni vs coli (hippurate historically; MALDI/molecular now)
Treatment Notes (conceptual)
- Supportive care for most uncomplicated cases
- Antibiotics (azithromycin often preferred; fluoroquinolones historically used) for severe, prolonged, pregnant, or immunocompromised
- Avoid antimotility agents in invasive diarrhea when possible
AMR
- Fluoroquinolone resistance very common (poultry antimicrobial use — One Health)
- Macrolide resistance less frequent but critical when FQ fails
- AST when treating invasive/refractory disease
Genomics & Computational Notes
- Highly recombining; Recombination in Bacterial Phylogenies complicates trees
- Outbreak attribution: cgMLST / allele schemes in foodborne networks
- LOS locus diversity linked to GBS-associated strains in research
Related Notes
- Helicobacter pylori · Salmonella enterica · Gastrointestinal Infections · Vibrio cholerae
- MOCs: MOC - Bacteriology · MOC - Public Health & Epidemiology · MOC - Antimicrobial Resistance (AMR)
Active Recall
- Why incubate Campylobacter plates at 42 °C?
- What post-infectious neurologic complication is classically linked?
- Why are fluoroquinolones often unreliable empirically?