The cure of a patient with a very resistant streptococcus viridans endocarditis with massive penicillin therapy (average daily dose of eighty-six million units)

Abstract

The effectiveness of penicillin in the treatment of nonhemolytic streptococcal endocarditis is well established. In most cases of subacute endocarditis, cure can be accomplished with conventional doses of penicillin, but now and then it is necessary to administer heroic doses. A review of reported treatment failures due to relapse or continued infection makes it quite clear that many such patients have not been given adequate daily doses of penicillin. If the circulating blood is not promptly sterilized or if relapse occurs subsequent to completion of a course of penicillin, it has been advised that the daily dose of penicillin should be drastically increased five- to tenfold; then the arrest of the infection would probably more nearly approach 100 per cent. 1 More than 90 per cent of the strains of nonhemolytic streptococcus are completely inhibited in vitro by 0.1 unit or less of penicillin per milliliter 2 and are classified as the sensitive group. 1 The moderately to very resistant group requires for inhibition of growth in vitro 0.5 to 10 units or more of penicillin per milliliter. The moderately sensitive group is inhibited by penicillin in vitro in amounts which are between the above two ranges. It has been recommended that patients infected with an organism which requires 1 unit of penicillin per milliliter for in vitro inhibition should receive a daily dose of at least 5,000,000 units of penicillin. 1 The purpose of this communication is to report a case of subacute bacterial endocarditis in which the patient was infected with a very resistant strain of Streptococcus viridans treated with an average daily dose of approximately 86,000,000 units of penicillin for a period of twenty-eight days.