Endocarditis caused by viridans streptococci and S. bovis group resistant to penicillin (MIC greater than 2 mg/L)
There is no established regimen for native or prosthetic valve endocarditis caused by viridans streptococci or S. bovis group resistant to penicillin (MIC greater than 2 mg/L) – seek expert advice. Data from animal studies and case reports support the use of the following regimen in adults and children:
vancomycin intravenously for 4 to 6 weeks; for initial dosing, see Intermittent vancomycin dosing for noncritically ill adults or Intermittent vancomycin dosing for young infants and children vancomycin vancomycin vancomycin
PLUS
gentamicin (adult and child) 1 mg/kg intravenously, 8-hourly for 4 to 6 weeks (monitor plasma concentration; see Principles of aminoglycoside use)1. gentamicin gentamicin gentamicin
The duration of therapy for patients with prosthetic valve endocarditis is 6 weeks. Depending on clinical progress, patients with native valve endocarditis may require between 4 and 6 weeks of therapy.
Although evidence is limited, ceftriaxone plus gentamicin may be considered as an alternative to the vancomycin plus gentamicin above, depending on the ceftriaxone MIC – seek expert adviceTurnidge, 2020.