Intravenous followed by oral antimicrobial therapy for staphylococcal endocarditis.

We have treated 35 cases of staphylococcal endocarditis in 33 patients with intravenous followed by oral antimicrobial therapy. All patients had three or more blood cultures positive for Staphylococcus aureus, and all had cardiac murmurs characteristic of valvular insufficiency. The mean total duration of antimicrobial therapy was 42.4 d, consisting of a mean of 16.4 d of intravenous therapy followed by a mean of 26 d of oral therapy. Intravenous antimicrobial therapy included sodium nafcillin (32 cases; mean dose 9.2 g daily) and clindamycin (three cases). Oral therapy included dicloxacillin or oxacillin (30 cases; mean dose 4.5 g daily), clindamycin (four cases), and potassium penicillin V (one case). Serum bactericidal titers using the blood culture isolates showed similar activity with both intravenous and oral drugs. All patients treated with this sequential intravenous and oral regimen were cured. A regimen of initial intravenous followed by oral antimicrobial therapy, monitored with serum antibacterial activity studies, is a safe, effective, well-tolerated, and economical treatment for staphylococcal endocarditis.