Adjunctive Rifampin for the Treatment of Prosthetic Valve Endocarditis Due to S. Aureus

Inclusion Criteria: 1. Probable or definite prosthetic valve endocarditis involving the tricuspid, pulmonic, mitral and/or aortic valves by the 2023 Duke-ISCVID Criteria (including Cardiac PET evidence if applicable); 2. Patient or healthcare proxy provide informed consent. Exclusion Criteria: 1. Death deemed imminent and inevitable within days or patient will be receiving palliative care and has prognosis \< 90 days according to the treating team; 2. Patient requires intensive care but has a do not resuscitate order precluding transfer; 3. Polymicrobial bacteremia (not including skin commensals or other recognized contaminant); 4. Organism tests as rifampin resistant; 5. History of hypersensitivity/anaphylaxis or severe adverse reaction to rifampin; 6. Category X or other important drug-drug interaction with rifampin which cannot be safely mitigated \[with as-needed consultation from experts from pharmacy and/or internal medicine/geriatrics for potential deprescribing\]; 7. Child Pugh Class C cirrhosis; 8. Clinician deems rifampin to be mandatory; 9. Patient has already received \>3 days of rifampin at time of screening or \>10 days of total therapy 10. Pregnancy or breast feeding Administrative exclusions: 1. No reliable means of outpatient contact (telephone/email/text); 2. Previously enrolled; 3. Prior S. aureus bacteremia within the preceding 180 days