Standard regimen for prosthetic valve endocarditis caused by methicillin-susceptible staphylococci
For prosthetic valve endocarditis caused by methicillin-susceptible staphylococci in adults and children, use:
flucloxacillin 2 g (child: 50 mg/kg up to 2 g) intravenously, 4-hourly for 6 weeks. For dosage adjustment in adults with kidney impairment, see flucloxacillin intravenous dosage adjustment. flucloxacillin flucloxacillin flucloxacillin
Some strains of S. aureus in Australia are penicillin-susceptible. If penicillin susceptibility is confirmed by a clinical microbiologist, consider using benzylpenicillin – seek expert advice.
Because staphylococcal endocarditis is associated with a high rate of mortality, some international consensus-based guidelines suggest adding gentamicin and rifampicin to flucloxacillin (based on experimental endocarditis models and limited clinical experience). However, retrospective data on staphylococcal prosthetic valve endocarditis suggest that the addition of rifampicin does not alter rates of one-year survival or relapse, compared with regimens not containing rifampicinLe Bot, 2021. In addition, combination therapy can be associated with significant toxicity, antimicrobial resistance and drug interactions; seek expert advice.