163.1 🎓 醫孞生版

163.1.0.1 📌 䞀頁重點

  • Haemophilus species:
    • H. influenzae — most clinical relevance
      • Type b (Hib): 過去 meningitis/epiglottitis #1 in < 5 yr; Hib vaccine 倧幅枛
      • Non-typeable (NTHi): AOM, sinusitis, COPD exacerbation, conjunctivitis, neonatal sepsis
    • H. parainfluenzae: HACEK IE
    • H. ducreyi: chancroid (痛 genital ulcer + LAP)
  • Moraxella catarrhalis: AOM, sinusitis, COPD exacerbation
  • Microbiology: 倧倚 gram - coccobacilli; H. influenzae 需 X + V factors (chocolate agar); H. ducreyi 需 nutritious + X factor
  • Treatment:
    • β-lactamase prevalence 高 (NTHi 25-40%, M. catarrhalis ~ 90-100%)
    • Amoxicillin-clavulanate, 2nd/3rd gen ceph (ceftriaxone), FQ, macrolide

163.1.0.2 1⃣ Haemophilus influenzae

163.1.0.2.1 现菌孞
  • Gram - coccobacillus
  • Fastidious — 需 X factor (hemin) + V factor (NAD) → chocolate agar
  • 6 capsular serotypes (a-f); type b (Hib) = past major pathogen
  • Non-typeable (NTHi): 無 capsule, 廣 mucosal pathogen
163.1.0.2.2 Hib (Type b)
  • Past meningitis #1 cause in < 5 yr (pre-vaccine, 1985)
  • Epiglottitis (“cherry red epiglottis”, airway emergency)
  • Cellulitis (face, buccal — characteristic violaceous)
  • Septic arthritis, osteomyelitis in children
  • Bacteremia, pneumonia, occult fever
  • Hib vaccine (conjugate, PRP-T/HbOC/PRP-OMP) — 1990s onwards, 99% reduction
  • Dose: 2, 4, 6, 12-15 mo
163.1.0.2.3 NTHi (Non-typeable H. influenzae)
  • AOM (small child, after pneumococcus)
  • Sinusitis (acute bacterial)
  • COPD acute exacerbation (#1 bacterial cause)
  • CAP (especially elderly, COPD)
  • Conjunctivitis
  • Neonatal sepsis (vertical), maternal chorioamnionitis
163.1.0.2.4 治療
  • Amoxicillin if β-lactamase neg (decreasing %)
  • Amoxicillin-clavulanate (preferred for AOM/sinusitis empiric — β-lactamase coverage)
  • 2nd gen ceph (cefuroxime), 3rd gen (ceftriaxone) for severe
  • Macrolide (azithromycin), Doxycycline, FQ (levofloxacin) alternatives
  • Meningitis: ceftriaxone 2 g q12h × 7d (Hib) + dexamethasone (especially child)

163.1.0.3 2⃣ Haemophilus ducreyi (Chancroid)

  • 熱垶 STI; declining globally but still endemic Africa, Caribbean, S. America
  • 痛 genital ulcer (vs syphilis painless chancre) + tender suppurative LAP (bubo)
  • Co-infection with HIV common (genital ulcer increase HIV risk)
  • Dx: clinical + culture (specific media, hard); PCR if available
  • Treatment:
    • Azithromycin 1 g PO × 1
    • Ceftriaxone 250 mg IM × 1
    • Ciprofloxacin 500 mg PO bid × 3d
    • Erythromycin 500 mg PO qid × 7d
  • HIV + immunosuppression → response slower, may need longer
  • Partner treat 10d window
163.1.0.3.1 鑑別 — Genital Ulcer
病 痛 LAP
Syphilis (chancre) 侍痛 Painless ±
HSV 痛 (multiple) Tender +
Chancroid (H. ducreyi) 痛 (deep) Tender, suppurative
LGV (C. trachomatis L1-3) Painless Tender, suppurative (groove sign)
Granuloma inguinale (Klebsiella granulomatis) Painless beefy ±

163.1.0.4 3⃣ H. parainfluenzae + HACEK IE

  • HACEK = H. parainfluenzae, Aggregatibacter actinomycetemcomitans/aphrophilus, Cardiobacterium, Eikenella, Kingella
  • Gram - fastidious; ~ 1-3% all IE
  • Slow-growing (4 wk hold + 5-7 d) — modern automated blood culture detects in 5 days
  • Subacute IE, native valve, normal mouth flora (some HACEK 牙霒 reservoir)
  • Treatment: ceftriaxone 2 g IV q24h × 4 wk (native) / 6 wk (prosthetic)
  • Ampicillin-sulbactam alt
  • Cure rate high (90%+)

163.1.0.5 4⃣ Moraxella catarrhalis

  • Gram - diplococcus (像 Neisseria 看起䟆)
  • Oxidase + (像 Neisseria)
  • DNAse + (鑑別 Neisseria DNase -)
  • Carrier 普遍 (40%+ small children)
  • 100% β-lactamase positive (BRO-1, BRO-2)
  • 臚床:
    • AOM (3rd cause after pneumococcus, NTHi)
    • Sinusitis
    • COPD acute exacerbation
    • Pneumonia (elderly, immunocompromise, COPD)
  • Treatment:
    • Amoxicillin-clavulanate (β-lactamase covered)
    • 2nd/3rd ceph, macrolide, doxy, FQ
    • Plain amoxicillin/ampicillin 沒甚 (β-lactamase)