174.1 🎓 醫孞生版

174.1.0.1 📌 䞀頁重點

  • Y. enterocolitica + Y. pseudotuberculosis — gram - rod, cold-tolerant (4°C grow → 冰箱貯攟 increase load)
  • Source:
    • Y. enterocolitica: pork (raw / undercooked) 䞻芁, milk, water; chitterlings (pig intestine) in 矎南 黑人瀟區 holiday outbreak classic
    • Y. pseudotuberculosis: rodents, birds, contaminated vegetable, water; 東歐 + 日本 outbreaks
  • 臚床:
    • Enteritis (兒童 mostly): fever + abdominal pain + 氎瀉/血䟿, 1-3 wk; 范 long course
    • “Pseudoappendicitis” — terminal ileum + mesenteric adenitis 像 急性 appendicitis (RLQ pain), 10-30% 開刀 扟䞍到 appendicitis
    • Bacteremia / sepsis — iron overload (hemochromatosis, β-thalassemia, deferoxamine treatment) 高 risk; iron 是 Yersinia virulence siderophore-like
    • Reactive arthritis post-Yersinia (HLA-B27)
    • Erythema nodosum (especially Y. pseudotuberculosis Scandinavia)
  • Transfusion-associated bacteremia: Y. enterocolitica 是 RBC contaminant 䞻芁 cause (cold-tolerant during storage)
  • Treatment:
    • 倧倚 self-limit, no antibiotic
    • Severe / bacteremia / immuno / iron overload → doxycycline + aminoglycoside, OR ceftriaxone, OR FQ + TMP-SMX

174.1.0.2 1⃣ 现菌孞

  • Gram - rod
  • Y. pestis (plague, Ch 164) vs Y. enterocolitica vs Y. pseudotuberculosis
  • Cold-tolerant — grows at 4°C
  • Bipolar staining (像 safety pin — same family)
  • Urease + (vs E. coli urease -)
  • Motile at 25°C, non-motile at 37°C (like Listeria)
  • Microaerophilic / facultative anaerobic

174.1.0.3 2⃣ Y. enterocolitica

174.1.0.3.1 Source
  • Pork — 䞻芁 reservoir; raw / undercooked
  • Chitterlings (pig intestine prep) — Black community US holiday meals classic outbreak
  • Milk (raw, contaminated post-pasteurization rare)
  • Water
  • Pets (puppy diarrhea)
  • 食物 refrigerated post-prep — Yersinia 繌續 grow
174.1.0.3.2 臚床 — 4 patterns
174.1.0.3.2.1 A. Enteritis (兒童, 70%)
  • 望䌏 1-11 d
  • 燒 + abdominal pain (RLQ) + 氎瀉 → 血䟿
  • 1-3 wk duration (longer than 倚 enteric)
  • Self-limit majority
174.1.0.3.2.2 B. “Pseudoappendicitis” (青少幎 / 幎茕成人)
  • Mesenteric adenitis + terminal ileitis
  • RLQ pain mimics acute appendicitis
  • 10-30% taken to OR for appendectomy → 扟到 normal appendix
  • CT: ileal wall thickening + mesenteric LAP
174.1.0.3.2.3 C. Bacteremia / Sepsis
  • 倚 iron overload 病人 (hemochromatosis, β-thalassemia chronic transfusion, deferoxamine treatment)
  • 為什麌: Yersinia uses iron (low siderophore production — depends on host iron)
  • Deferoxamine = chelator → makes iron available to Y. enterocolitica → enhanced growth
  • Sx: 高燒, septic shock, multi-focal abscess (liver, spleen, lung, kidney), endocarditis, mycotic aneurysm
  • Mortality 高
174.1.0.3.2.4 D. Post-infectious
  • Reactive arthritis (HLA-B27) 1-3 wk later
  • Erythema nodosum (Scandinavia common)
  • Glomerulonephritis rare
174.1.0.3.3 Special: Transfusion-Associated Bacteremia
  • Y. enterocolitica = leading bacterial cause of RBC unit contamination
  • 因為 cold-tolerant (4°C blood bank storage)
  • Donor with mild diarrhea / asymptomatic bacteremia 1-2 wk earlier
  • Recipient: sepsis æ•ž hours 內 transfusion
  • 矎國 + Taiwan blood banks: pathogen reduction technology + donor screening

174.1.0.4 3⃣ Y. pseudotuberculosis

  • Rodents, birds, animals; contaminated vegetable / water
  • Outbreaks in 日本 (Far East scarlet fever), Russia, Europe
  • Sx: similar — enteritis + mesenteric adenitis + pseudoappendicitis
  • Erythema nodosum common Scandinavia
  • Far East scarlet-like fever (Izumi fever) — 玅疹 + arthritis + 燒, mimics 玅熱 / 川厎 / scarlet fever
  • Septicemia rarer than Y. enterocolitica
  • Treatment: ceftriaxone / FQ if severe

174.1.0.5 4⃣ Diagnosis

  • Stool culture — needs CIN agar (cefsulodin-irgasan-novobiocin) selective; cold enrichment
  • Blood culture in bacteremia
  • GI PCR panel (BioFire) includes Y. enterocolitica
  • Serology: cross-reacts with Brucella, Rickettsia — limited
  • Notifiable (some jurisdictions)

174.1.0.6 5⃣ Treatment

174.1.0.6.1 A. Enteritis (Healthy)
  • No antibiotic (self-limit, antibiotic 䞍 shorten course)
  • Hydration
174.1.0.6.2 B. Severe / Bacteremia / Iron Overload / Immuno
  • Ceftriaxone 2 g IV qd OR
  • Doxycycline + Aminoglycoside (gent/tobra) 經兞 regimen, especially iron overload
  • Ciprofloxacin (alt — but R emerging some regions)
  • TMP-SMX (alt)
  • 4-6 wk for invasive / endovascular
174.1.0.6.3 C. Iron Overload Management
  • Stop deferoxamine (worsens Yersinia)
  • Deferiprone or deferasirox (newer chelators — less Yersinia risk)
  • Lower transfusion if possible
174.1.0.6.4 D. Surgical (Abscess)
  • Drain liver / splenic / etc. abscess

174.1.0.7 6⃣ Prevention

  • Cook pork > 70°C
  • Avoid raw pork / chitterlings
  • Hand hygiene 接觞 chitterlings / raw pork
  • Refrigerate but consume timely (4°C grow!)
  • Iron overload education: avoid raw meats + GI sx → seek care