- For MSSA endocarditis, nafcillin, oxacillin or cefazolin for 6 weeks are all acceptable treatment strategies per the AHA guidelines. In rare cases when staph in penicillin susceptible, penicillin can be used if the MIC is <0.1 mcg/mL and does not have beta-lactamase in vitro
- 2 weeks of therapy can be given for uncomplicated endocarditis (no metastatic infection or secondary cardiac problems) if synergistic therapy with gentamicin can be given.
- There is no indication for gentamicin with anti-staph therapy for complicated IE or left-sided IE, as is has in vitro benefit, but no improved clinical outcomes and significant renal toxicity
- Indications for surgery for IE are the following: (per ACC guidelines)
- IE-associated valvular dysfunction (AI or MR) causing heart failure
- Extension of infection forming abscess, fistula, or heart block
- Difficult to treat pathogen (fungal or highly resistant organisms)
- Persistent bacteremia despite appropriate therapy and exclusion of other causes
- Recurrent embolization with persistent vegetations despite appropriate antibiotics
- There is no consensus about the number of type of emboli that should prompt surgical intervention
- Interestingly, among patients with surgical indications who did not undergo surgery, having staph aureus as the infectious agent was an independent predictor for not going to surgery, usually because of concurrent sepsis and stroke
- Many studies have been done on timing of surgery for IE. One review of the evidence found that there is no benefit to delaying surgery in those with clear indications (AI with heart failure, paravalvular extension of infection, or ongoing embolism), as prognosis for these patients with medical therapy alone is poor.
Circulation 2005; 111:3167; J Antimicrob Chemother 2012; 67:269; Eur Heart J 2009; 30:2369.
Chu VH, Park LP, Athan E, et al. Association between surgical indications, operative risk, and clinical outcome in infective endocarditis: a prospective study from the International Collaboration on Endocarditis. Circulation 2015; 131:131.