Antimicrobial therapy of streptococcal endocarditis.

The majority of patients with endocarditis caused by viridans streptococci or Streptococcus bovis susceptible to less than or equal to 0.1 mg/l of penicillin may be treated successfully for two weeks with penicillin 20 X 10(6) million units intravenously together with streptomycin 7.5 mg/kg body weight intramuscularly twice daily or gentamicin 1 mg/kg body weight intravenously every 8 h. Patients with nutritionally variant viridans streptococcal endocarditis should be treated for four weeks with penicillin combined with an aminoglycoside in dosages as above, which will require adjustment when renal impairment is present. Patients with enterococcal endocarditis should be treated with penicillin together with an aminoglycoside in dosages as above for four to six weeks. Patient with enterococcal endocarditis with symptoms of infection less than three months in duration or with aortic valve endocarditis may be treated successfully for four weeks with antimicrobial therapy; patients with symptoms of infection longer than three months in duration or with mitral valve infection should receive six weeks of antimicrobial therapy. Patients with enterococcal endocarditis who relapse should be treated for six weeks of antimicrobial therapy.