Infective endocarditis

Background

• Infection of heart valves, either prosthetic or native

Organisms

• Bacteria
  • Staphylococcus aureus (most common)
  • Viridans group streptococci
  • Coagulase-negative staphylococci
  • Other streptococci
  • Enterococci
  • HACEK group
  • Coxiella
  • Brucella
• Fungi
  • Candida

Clinical Presentation

• Refer to Modified Duke criteria
• Specific organisms may be associated with specific risk factors
  • Injection drug use: Viridans group streptococci and Pseudomonas aeruginosa
  • Colon cancer: [Streptococcus bovis]] and Clostridium septicum

Management

• Varies by causative organism and prosthetic vs. native valve

Indication	Antibiotic	Dose	Duration	Notes
MSSA and other oxacillin-susceptible Staphylococcus
NVE	oxacillin	2 g IV q4h	6 weeks	can treat for 2 weeks in uncomplicated right-sided NVE
NVE	cefazolin	2 g IV q8h	6 weeks	in patients with non-anaphylactoid penicillin allergy
PVE	oxacillin	2 g IV q4h	≥6 weeks	use cefazolin or vancomycin if allergy
	+ rifampin	300 mg IV/PO q8h
	+ gentamicin	1 mg/kg IV/IM q8h	2 weeks
MRSA and other oxacillin-resistant Staphylococcus
NVE	vancomycin	15 mg/kg IV q12h	6 weeks	target trough 10-20 μg/mL
NVE	daptomycin	≥8 mg/kg/dose	6 weeks
PVE	vancomycin	15 mg/kg IV q12h	≥6 weeks	target vancomycin trough of 10-20 μg/mL
	+ rifampin	300 mg IV/PO q8h
	+ gentamicin	1 mg/kg IV/IM q8h	2 weeks
Enterococcus susceptible to penicillin and gentamicin
NVE or PVE	ampicillin	2 g IV q4h	4-6 weeks	4 weeks if symptoms <3 months; 6 weeks if symptoms >3 months or if PVE
	+ gentamicin	1 mg/kg IV q8h
NVE or PVE	ampicillin	2 g IV q4h	6 weeks	alternative regimen if CrCl <50
	+ ceftriaxone	2 g IV q12h
Enterococcus susceptible to penicillin and resistant to aminoglycosides
NVE or PVE	ampicillin	2 g IV q4h	6 weeks
	+ ceftriaxone	2 g IV q12h
Enterococcus resistant to penicillin and susceptible to vancomycin and aminoglycosides
NVE or PVE	vancomycin	15 mg/kg IV q12h	6 weeks
	+ gentamicin	1 mg/kg IV/IM q8h
Enterococcus resistant to penicillin, aminoglycosides, and vancomycin
NVE or PVE	linezolid	600 mg IV/PO q12h	>6 weeks
NVE or PVE	daptomycin	10-12 mg/kg IV q24h	>6 weeks
Viridans Streptococcus or Streptococcus gallolyticus highly susceptible to penicillin (MIC ≤0.12 μg/mL)
NVE	crystalline penicillin G	3-4 MU IV q4h	4 weeks
NVE	ceftriaxone	2 g IV/IM q24h	4 weeks
NVE	penicillin or ceftriaxone	as above	2 weeks
	+ gentamicin	3 mg/kg IV/IM q24h
NVE	vancomycin	15 mg/kg IV q12h	4 weeks	use if allergy, target 10-15 μg/mL
PVE	crystalline penicillin G	6 MU IV q4h	6 weeks
	± gentamicin	3 mg/kg IV/IM q24h	2 weeks
PVE	ceftriaxone	2 g IV/IM q24h	6 weeks
	± gentamicin	3 mg/kg IV/IM q24h	2 weeks
PVE	vancomycin	15 mg/kg IV q12h	6 weeks	use if allergy
Viridans Streptococcus or Streptococcus gallolyticus relatively resistant to penicillin (MIC >0.12 μg/mL)
NVE	crystalline penicillin G	6 MU IV q4h	4 weeks
	+ gentamicin	3 mg/kg IV/IM q24h
NVE	vancomycin	15 mg/kg IV q12h	4 weeks	use if allergy, target 10-15 μ/mL
PVE	crystalline penicillin G	6 MU IV q4h	6 weeks
	+ gentamicin	3 mg/kg IV/IM q24h
PVE	ceftriaxone	2 g IV/IM q24h	6 weeks
	+ gentamicin	3 mg/kg IV/IM q24h
PVE	vancomycin	15 mg/kg IV q12h	6 weeks	use if allergy
Streptococcus pneumoniae
NVE	penicillin		4 weeks
NVE	cefazolin		4 weeks
NVE	ceftriaxone		4 weeks
PVE	penicillin		6 weeks
PVE	cefazolin		6 weeks
PVE	ceftriaxone		6 weeks
Streptococcus pyogenes
NVE	crystalline penicillin G		4 weeks
NVE	ceftriaxone		4 weeks
PVE	crystalline penicillin G		6 weeks
PVE	ceftriaxone		6 weeks
Group B, C, or G Streptococcus
NVE	crystalline penicillin G		4 weeks
	± gentamicin		2 weeks
NVE	ceftriaxone		4 weeks
	± gentamicin		2 weeks
PVE	crystalline penicillin G		6 weeks
	± gentamicin		2 weeks
PVE	ceftriaxone		6 weeks
	± gentamicin		2 weeks
HACEK bacterium
NVE	ceftriaxone	2 g IV/IM q24h	4 weeks
PVE	ceftriaxone	2 g IV/IM q24h	6 weeks
NVE or PVE	ciprofloxacin	500 mg PO q12h	6 weeks