Treatment of Bacteroides endocarditis with carbenicillin.

A heroin addict developed acute bacterial endocarditis with Streptococcus viridans and Bacteroides melaninogenicus. Although blood cultures became negative during penicillin G and clindamycin therapy there was little clinical response. Prompt clinical improvement was achieved with intravenous carbenicillin in a dose of 40 g daily. In vitro testing supported the superiority of carbenicillin therapy in this patient.