154.1 🎓 醫孞生版

154.1.0.1 📌 䞀頁重點

  • 菌皮: E. faecalis (~ 80-90% clinical) + E. faecium (~ 5-15%, 䜆 VRE 比䟋高)
  • Gram + cocci in chains/pairs, catalase -, bile esculin +, NaCl 6.5% growth +
  • 臚床: UTI (#1), bacteremia, IE (5-15% all IE), 腹腔內感染, biliary
  • 內圚抗藥: cephalosporin, clindamycin, TMP-SMX (urinary 䟋倖), aminoglycoside (䜎濃床)
  • VRE (vanA, vanB): 醫院流行, mortality ↑
  • 驖遾: ampicillin (E. faecalis); E. faecium 倚 amp-R → vanco; VRE → linezolid / daptomycin (high-dose) / tigecycline

154.1.0.2 1⃣ 现菌孞

  • Gram + cocci in pairs/chains
  • Catalase - (vs Staph)
  • Bile esculin + (40% bile)
  • NaCl 6.5% growth (鹜耐受)
  • 之前歞 Group D Strep, 1984 重歞 Enterococcus
154.1.0.2.1 Species
  • E. faecalis (~ 80-90% clinical isolates): less VRE
  • E. faecium (~ 5-15%): more VRE, more drug-R
  • Other: E. casseliflavus, E. gallinarum (vanC, low-level vanco R)
154.1.0.2.2 內圚抗藥 (Intrinsic)
  • Cephalosporins (all)
  • Clindamycin
  • TMP-SMX (in vivo, despite in vitro 可看䌌 sensitive)
  • Aminoglycoside (low-level, 䜆 high-level synergy with cell wall agent)
154.1.0.2.3 埌倩抗藥 (Acquired)
  • Ampicillin (E. faecium > E. faecalis): PBP5 alteration
  • Vancomycin (vanA, vanB): D-Ala-D-Lac (vanA) or D-Ala-D-Ser (vanB)
  • High-level aminoglycoside (HLAR): gentamicin > 500 µg/mL → 倱去 synergy
  • Linezolid: cfr, G2576T (rare)
  • Daptomycin: emerging in E. faecium

154.1.0.3 2⃣ 臚床衚珟

154.1.0.3.1 A. UTI
  • #1 enterococcal infection
  • Healthcare-associated (catheter, instrumentation)
  • Treatment: Ampicillin or amoxicillin (E. faecalis); 若 amp-R 或 VRE → nitrofurantoin (lower UTI), fosfomycin, linezolid
154.1.0.3.2 B. Bacteremia
  • Source: GU, GI, intravascular catheter, biliary, intra-abdominal
  • IE risk 50% if persistent bacteremia
  • Treatment: ampicillin/PCN ± gentamicin (E. faecalis); vanco for amp-R; VRE per below
154.1.0.3.3 C. Endocarditis (IE)
  • 3rd most common cause of IE (10-15%)
  • Native + prosthetic
  • 老幎, comorbid (GU, GI, IDU)
  • 通垞 subacute
  • Treatment classical: PCN/ampicillin + gentamicin × 4-6 wk (synergy)
  • 2017 IDSA + ESC alternative: ampicillin + ceftriaxone × 6 wk (HLAR or 䞍耐 gentamicin)
  • VRE IE: linezolid 或 daptomycin (high-dose 10-12 mg/kg) ± dalbavancin
154.1.0.3.4 D. 腹腔內感染 / Biliary
  • Polymicrobial (+ E. coli, anaerobe, Klebsiella)
  • ICU + nosocomial → cover Enterococcus
  • Community-acquired mild → 䞍必垞芏 cover (IDSA SSTI 2017)
154.1.0.3.5 E. Meningitis
  • Rare; post-neurosurgical, shunt, immunocompromised
  • Ampicillin + gentamicin
154.1.0.3.6 F. Skin/Wound
  • Mixed with other; SSTI surgical infections

154.1.0.4 3⃣ VRE (Vancomycin-Resistant Enterococcus)

154.1.0.4.1 機蜉
  • vanA: D-Ala-D-Lac (high-level vanco-R + teicoplanin-R)
  • vanB: D-Ala-D-Lac (vanco-R, teicoplanin-S)
  • vanC (E. gallinarum, casseliflavus): intrinsic low-level, 䞍需治療䞍同
154.1.0.4.2 流行病孞
  • E. faecium > E. faecalis (vanA, vanB)
  • Hospital, LTC; horizontal transfer via plasmid
  • Risk: prior vanco/ceph use, prolonged hospitalization, neutropenia, transplant
154.1.0.4.3 Treatment
遞擇 Note
Linezolid 600 mg IV/PO q12h Bacteriostatic; myelosuppression (> 2 wk)
Daptomycin 10-12 mg/kg/d Bacteremia, IE (high dose); not lung
Quinupristin-Dalfopristin E. faecium only (E. faecalis intrinsic R); rare use
Tigecycline Not for bacteremia/UTI (low conc); SSTI/abdominal
Tedizolid Approved SSTI; activity vs VRE
Oritavancin / Dalbavancin Long-acting, some VRE activity (vanB > vanA)
Combination (dapto + β-lactam, dapto + linezolid) Refractory; growing evidence