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

Organism	Indication	Antibiotic	Dose	Duration	Notes
MSSA and other oxacillin-susceptible Staphylococcus	NVE	oxacillin	12 g/day IV in 4-6 divided doses	6 weeks	can treat for 2 weeks in uncomplicated right-sided NVE
MSSA and other oxacillin-susceptible Staphylococcus	NVE	cefazolin	6 g/day IV in 3 divided doses	6 weeks	in patients with non-anaphylactoid penicillin allergy
MRSA and other oxacillin-resistant Staphylococcus	NVE	vancomycin	30 mg/kg/day IV in 2 divided doses	6 weeks	target trough 10-20 μg/mL
MRSA and other oxacillin-resistant Staphylococcus	NVE	daptomycin	≥8 mg/kg/dose	6 weeks
MSSA and other oxacillin-susceptible Staphylococcus	PVE	oxacillin, plus rifampin, plus gentamicin	12 g/day in 6 divided doses 900 mg/day IV or PO in 3 divided doses 3 mg/kg/day IV or IM in 2-3 divided doses	≥6 weeks ≥6 weeks 2 weeks	use cefazolin or vancomycin if allergy
MRSA and other oxacillin-resistant Staphylococcus	PVE	vancomycin, plus rifampin, plus gentamicin	30 mg/kg/day in 2 divided doses 900 mg/day IV or PO in 3 divided doses 3 mg/kg/day IV or IM in 2-3 divided doses	≥6 weeks ≥6 weeks 2 weeks	target trough of 10-20 μg/mL