S. aureus (right-sided/tricuspid valve)
- Tricuspid valve involvement - rule out septic pulmonary emboli.
- Surgical consult recommended if:
persistent bacteremia > 5 days of appropriate therapy
tricuspid valve vegetations ≥ 20mm + recurrent pulmonary embolism.
right-sided heart failure due to triscuspid valve regurgitation
- NB: No longer recommend addition of gentamicin for native valve S. aureus endocarditis as:
no difference in clinical cure, mortality, or relapse
increased risk of nephrotoxicity.
Oral therapy
- Switch to oral regimen can be considered if patient unable to complete IV course of antibiotics; must ensure:
- clinical improvement, including blood culture clearance, surgical debridement of metastatic foci, and resolution of fever, chills, malaise
- susceptibility of S. aureus to chosen regimen.
Oral regimens include:
- Quinolone (e.g. ciprofloxacin 750mg PO bid) + rifampin 300mg PO tid or 600mg PO bid (NB: drug-drug interaction with rifampin and methadone). Levofloxacin has better in vitro S. aureus activity.
- Cephalexin 1g PO qid + rifampin 600mg PO bid (NB: drug-drug interaction with rifampin and methadone)
- Linezolid 600mg PO bid + rifampin 600mg PO bid (NB: drug-drug interactions with linezolid and opioids, and rifampin and methadone)
- TMP-SMX 2 DS tabs PO bid-tid (no RCT data)
- Doxycycline 100mg PO bid (no RCT data)
| Therapy | Dose | Duration |
|---|---|---|
| Cloxacillin | 2g IV q4h | 4-6 weeks |
| or | ||
| Cefazolin | 2g IV q8h | 4-6 weeks |
| Severe penicillin allergy/anaphylaxis | ||
| Vancomycin | 15mg/kg IV q8-12h | 4-6 weeks |
| Intolerant to vancomycin or vancomycin MIC > 2µg/mL | ||
| Daptomycin | 8-10mg/kg IV daily | 4-6 weeks |
Cloxacillin resistant (MRSA)
| Therapy | Dose | Duration |
|---|---|---|
| Vancomycin MIC ≤ 2µg/mL | ||
| Vancomycin | 15mg/kg IV q8-12h | 6 weeks |
| Intolerant to Vancomycin or MRSA with vancomycin MIC > 2µg/mL | ||
| Daptomycin | 8-10mg/kg IV daily | 6 weeks |