Empirical therapy

Treatment of IE should be started promptly only in patients who are in frank sepsis or who are hemodynamically unstable. As blood culture data is crucial in antibiotic selection, in stable patients with recent antibiotic exposure it is reasonable to stop all antibiotics and draw blood cultures after an antibiotic free interval. Three sets of blood cultures should be drawn at 30 minutes interval before the initiation of antibiotics.

Empirical antibiotic therapy for IE (pending blood culture results)
Native Valve IE Etiologies (usual) Suggested Regimens (Primary) Adjunct Diagnostic or Therapeutic Measures or comments
  Empirical Treatment- awaiting cultures
(No h/o skin/soft tissue infection or abscesses, no h/o IV drug abuse, no h/o CVC line or recent cardiac/prosthetic valve replacement)  		   VGS, Enterococci, NVS,  Streptococcus gallolyticus,   Ampicillin-sulbactam 3g q6h 
(Ampicillin- 150mg/kg/day
or Sulbactam 50 mg/kg/day ) in 4 divided doses or Ampicillin 2 g IV in q4h
Or 200 mg/kg/day in six divided doses
plus
Ceftriaxone 2 g IV q24h
Paed Dose: 50-100 (60 mg/kg/day) in two divided doses Plus
Gentamicin 1 mg/kg q8h 		  Gentamicin used for synergy, peak levels need not exceed 4 mcg/ml.
  • Advantage of Ampicillin-sulbactam (AS) over CP/Ampicillin: AS Covers β-lactamase producing Enterococci & HACEK Group of organisms
  • Combination of ceftriaxone with Gentamicin does not cover Enterococcus, Nutritionally variant Streptococci (Abiotrophica & Granulicatella)
Native Valve IE
(Risk factors for S. aureus) 		MSSA, CA-MRSA, HA-MRSA*** Vancomycin
25 mg/kg loading dose followed by 30per/kg  per 24 h IV in 2-3 equally divided doses Alternative Therapy: Daptomycin 6 mg/kg q24h
(for Right-sided IE) Or 8-10  mg/kg q24h (For left- sided IE) For Possible MSSA: Flucloxacillin or Cefazolin 		Vancomycin trough levels -1 hour before the 4rth dose of vancomycin Recommended Vancomycin. trough levels in serious MRSA infections- 15-20 μg/ml. Nephrotoxicity (0-12%) which is associated with
vancomycin trough levels greater than or equal to 15 μg/mL, in those receiving high dose vancomycin         ( greater or equal to 4
g/day), concomitant use of nephrotoxic agents, and duration
of vancomycin therapy
  PVE pending blood cultures or with negative blood cultures     Ceftriaxone 2 g IV q24h
Paed Dose: 50-100 (60 mg/kg/day) in two divided doses
AND
Vancomycin (25 mg/kg loading dose followed by 30-60 mg/kg per 24 h IV) 
AND
Gentamicin 1mg/kg q12h
AND
Rifampicin   300-600 mg q12H  po/IV   		Use lower dose of rifampicin in severe renal impairment.
  • *NVS – Nutrionally variant streptococci
  • **CP- crystalline penicillin
  • ***MSSA- methicillin sensitive Staphylococcus aureus,  CA-MRSA- community- acquired methicillin resistant Staphylococcus aurueus, HA-MRSA- hospital acquired methicillin resistant staphylococcus aureus