171.1 🎓 醫學生版

菌: Campylobacter jejuni (90%+ human disease) > C. coli, C. fetus
Microbiology: Gram - curved/comma rod, microaerophilic, 42°C grow (selective culture), oxidase +, motile (single polar flagellum)
Source: poultry (chicken) main, raw milk, untreated water, pets
Low ID (~ 500 organisms)
臨床:
- Enteritis (#1 form): 燒 + 急 cramping + 水樣 → 血便 (often), 1 wk
- Bacteremia (immunocompromise, HIV, hypogammaglob)
- Extraintestinal: cholecystitis, pancreatitis, UTI
Post-infectious sequelae:
- GBS (Guillain-Barré) — 30% GBS post-Campy (molecular mimicry of LOS to gangliosides)
- Reactive arthritis (HLA-B27)
- IBD trigger
Treatment:
- 大多 self-limit, supportive ORS
- Antibiotic if severe / 高 risk / immuno / 長 duration / 血便:
  - Azithromycin 500 mg PO qd × 3d (preferred — FQ R 升)
  - Cipro / levofloxacin (R 50%+ in Asia)
  - Doxycycline (alt)
C. fetus: bacteremia + IE + meningitis in elderly / immuno; ceftriaxone

Gram - curved / S-shaped rod
Microaerophilic (5-10% O2)
Optimal 42°C (avian temperature) — selective lab culture
Motile (single polar flagellum, “darting motility”)
Oxidase +, catalase +
多 species; C. jejuni > C. coli > C. fetus > rare (C. lari, C. upsaliensis)
C. fetus: 36°C preferred grow (低 temp), more invasive

Poultry contamination at slaughter — Campy in chicken gut, contaminates carcass
Undercooked chicken (most common Western)
Raw milk, untreated water (campers, mountain water), 接觸 animals
Pet feces (puppy, kitten with diarrhea)
Travel SE Asia, S Asia
低 ID (~ 500 cells) — easy infection

Healthy: rare
Immunocompromised (HIV, hypogammaglob, X-linked agammaglobulinemia, malignancy)
C. fetus — distinct: elderly + atherosclerosis + immunocompromise; bacteremia, IE, meningitis, mycotic aneurysm (like Salmonella)
Treatment: ceftriaxone / carbapenem

~ 30% of GBS preceded by Campylobacter infection (molecular mimicry: LOS sialic acid + gangliosides GM1/GQ1b → autoimmune attack on peripheral nerves)
1-3 wk after enteritis
Ascending flaccid paralysis + areflexia
Miller Fisher variant (ophthalmoplegia + ataxia + areflexia) — anti-GQ1b
CSF: albuminocytologic dissociation
EMG: demyelination
Tx: IVIG or plasmapheresis; supportive vent

Stool culture with Campy-selective (Skirrow, Campy-BAP) at 42°C, microaerophilic
GI PCR panel (BioFire FilmArray) — fast detection
Gram stain: curved gram - rods, “seagull” appearance
通報 (notifiable)

健康成人 mild → supportive only
Antibiotic indications:
- Severe (> 7 d, 多 episode, weight loss, 血便)
- Immunocompromised
- 高 risk extraintestinal
- Bacteremia
- Pregnant (Campy carries risk to fetus)
Drugs:
- Azithromycin 500 mg PO qd × 3d (preferred 因 FQ R 升; macrolide low R in Campy)
- Ciprofloxacin 500 mg bid × 3-5d (if S) — Asia + Spain + USA up to 50% R
- Doxycycline / TMP-SMX alt
C. fetus: ceftriaxone or carbapenem (severe / IE)
GBS: IVIG / plasmapheresis — abx 不改 GBS course (after immune mimicry started)