Successful Treatment of C. Diphtheriae Subacute Bacterial Endocarditis With Penicillin and Streptomycin

C. diphtheriae is an unusual causative organism in subacute bacterial endocarditis as only 17 cases have been recorded and none of these has survived. The 8 year old girl in this report is the first patient to have recovered. This child had two positive blood cultures for virulent intermedius strain of C. diphtheriae which was sensitive to 0.05 u./ml. of penicillin and to 3.0 u/ml. of streptomycin. The patient received penicillin therapy for one month and responded poorly. When streptomycin was also administered there was dramatic improvement. This clinical experiment tends to substantiate Hewitt's work in animals which demonstrates that streptomycin is much more effective than penicillin in saving guinea pigs injected with C. diphtheriae. In vitro tests with the organism isolated in this patient revealed neither evidence of synergism nor antagonism when studied with combinations of penicillin, streptomycin, sodium sulfadiazine and aureomycin. It is suggested in future cases that a combination of penicillin and streptomycin be used and that sensitivity tests be performed on the organism so that the physician may determine the proper dosage of antibiotic.