160.1 🎓 醫孞生版

160.1.0.1 📌 䞀頁重點

  • 菌: Gram + anaerobic spore-former, formerly Clostridium difficile — 改 Clostridioides difficile (2016)
  • Toxin A (enterotoxin, TcdA) + Toxin B (cytotoxin, TcdB) — pathogenic
  • B1/NAP1/027 strain: hypervirulent (toxin overproduction, FQ R) — 2000s outbreak, now declining
  • Risk: antibiotics, hospitalization, ≥ 65, GI surgery, PPI, IBD, immunosuppression
  • Sx: watery diarrhea + cramping + leukocytosis + low-grade fever; 嚎重 → toxic megacolon / perforation / sepsis
  • Dx: NAAT (PCR) + EIA toxin combination (2-step); 或 GDH + toxin EIA; 䞍芁 test 䞍 watery 或 < 3 stool / day
  • Treatment 2024 IDSA + ACG:
    • First episode: Fidaxomicin 200 mg PO bid × 10d 驖遾 (PO vanco 替代)
    • Severe: fidaxomicin or PO vanco + IV metro if fulminant
    • Fulminant (ileus/megacolon/shock): PO vanco 500 mg q6h + IV metronidazole 500 mg q8h + 手術 consult
    • Recurrence: fidaxomicin (if not used) → bezlotoxumab adjunct → FMT / RBX2660 / SER-109 for multi-recurrent
  • 預防: 抗生玠 stewardship + isolation + soap-water hands (alcohol gel 殺䞍死 spores) + chlorhexidine / bleach

160.1.0.2 1⃣ 现菌孞 + 臎病

  • C. difficile: Gram + anaerobic spore-forming rod
  • Spores 環境耐受 (alcohol-resistant)
  • 2 main toxins:
    • TcdA (enterotoxin): 黏膜損, fluid secretion
    • TcdB (cytotoxin): 䞻芁 virulence; bezlotoxumab targets
    • 兩 toxin glucosylate Rho GTPase → 现胞骚架 disrupt → 黏膜 break, neutrophil influx, pseudomembrane
160.1.0.2.1 Hypervirulent Strain (NAP1/027/BI)
  • Toxin overproduction (regulatory gene tcdC deletion)
  • Binary toxin (CDT)
  • FQ resistance
  • 2000s 倧 epidemic; 還有 䜆 prevalence ↓
  • 䞍圱響 treatment choice 䞻芁
160.1.0.2.2 埩癌機蜉
  • Spores 圚 colon 殘留
  • 抗生玠䞀停 → 再增殖
  • ~ 20-25% 第䞀次 recurrence rate
  • 之埌 ~ 40-60% 埌續 recurrence

160.1.0.3 2⃣ 臚床衚珟

160.1.0.3.1 A. Mild-Moderate Colitis
  • Watery, 非血䟿 (10-20×/d), cramping, low-grade fever
  • WBC ↑, low albumin
160.1.0.3.2 B. Severe Colitis
  • WBC > 15,000, Cr ≥ 1.5× baseline
  • Pseudomembrane on endoscopy (yellowish plaques)
160.1.0.3.3 C. Fulminant Colitis
  • Toxic megacolon (colon > 6 cm), ileus, sepsis, perforation, peritonitis
  • ICU
  • 手術 (subtotal colectomy or diverting loop ileostomy + vanco lavage)
  • Mortality 高
160.1.0.3.4 D. Recurrent CDI
  • Sx + (after) within 8 wk of completion of treatment
  • 1st recurrence ~ 20%, then 40-60% subsequent

160.1.0.4 3⃣ 蚺斷

160.1.0.4.1 䜕時 Test?
  • ≥ 3 unformed stools / 24 hr + 無 laxative
  • 䞍 test asymptomatic / formed stool / < 3 stool
160.1.0.4.2 Test Methods (IDSA 2-step)
Step Test Note
1 NAAT (PCR) OR GDH EIA sensitivity 高 (detects gene/protein)
2 Toxin EIA specificity 高 (detects active toxin)

結果解讀:

  • NAAT + + Toxin + = active CDI → treat
  • NAAT + + Toxin - = colonization or mild → 看臚床, 䞍䞀定 treat (high stool burden 仍 treat)
  • NAAT - = no CDI
160.1.0.4.3 圱像
  • AXR / CT colon: 嚎重 toxic megacolon, ascites, “thumbprinting” mucosal edema
  • Colonoscopy: 䞍必䟋行; severe で pseudomembrane visualize (risk perforation)
160.1.0.4.4 Stool Test 䞍重耇
  • 䞍芁 test of cure (NAAT/toxin 可 + weeks)
  • 埩癌症狀 → 再 test

160.1.0.5 4⃣ 治療 (IDSA + ACG 2024)

160.1.0.5.1 A. Initial Episode (Non-severe)
  • Fidaxomicin 200 mg PO bid × 10d (驖遾 — lower recurrence)
  • Vancomycin 125 mg PO qid × 10d (alt, equally efficacious cure but more recurrence)
  • Metronidazole — no longer first-line (2017 IDSA: 䞍 inferior trial result)
160.1.0.5.2 B. Severe
  • Fidaxomicin or Vancomycin 125 mg PO qid × 10d
160.1.0.5.3 C. Fulminant (shock, ileus, megacolon)
  • Vanco 500 mg PO q6h (or NG + per rectal 500 mg in 100 mL saline q6h enema if ileus)
  • + IV Metronidazole 500 mg q8h (adjunct)
  • Surgical consult: subtotal colectomy or diverting loop ileostomy
  • ICU resus
160.1.0.5.4 D. First Recurrence
  • Fidaxomicin (if not used initially)
  • 或 Vancomycin pulsed-tapered: 125 qid × 10d → bid × 7d → qd × 7d → q2-3d × 2-8 wk
  • + Bezlotoxumab 10 mg/kg IV × 1 (adjunct — adds to cure not stand-alone): 適 ≥ 65, immunocompromise, severe, prior recurrence
160.1.0.5.5 E. Multi-Recurrent
  • FMT (Fecal Microbiota Transplant) — colonoscopy / NG / capsule routes
  • RBX2660 (Rebyota, FDA 2022) — enema microbiota
  • SER-109 (Vowst, FDA 2023) — oral spore live biotherapeutic
  • Cure 80-90%
160.1.0.5.6 F. Bezlotoxumab Indications
  • mAb anti-toxin B
  • 10 mg/kg IV × 1 alongside SoC (vanco / fidaxomicin)
  • 降 recurrence ~ 38% → ~ 17% (MODIFY trials)
  • 䞍 stand-alone
  • 高 risk: ≥ 65, prior recurrence, immunocompromise, severe
  • HF caution (small ↑ HF hospitalization)
  • 健保 (Taiwan): 限 specific indication

160.1.0.6 5⃣ 預防

  • Antibiotic stewardship — 重芁; clinda, FQ, 3rd-gen ceph high risk
  • Contact isolation (gloves + gown), dedicated equipment
  • Hand hygiene with soap + water — alcohol gel 殺䞍死 spores!
  • Environmental cleaning — chlorine bleach 0.5%
  • 䞍 routine probiotic 預防 (mixed evidence)
  • PPI use review