Because of problems of penicillin allergy or lack of veins for intravenous administration of antibiotics, nine patients with endocarditis were treated with clindamycin, administered intramuscularly. Five patients were heroin addicts with staphylococcal endocarditis and four had α-streptococcal endocarditis. The only therapeutic failure occurred in a patient with a strain of Staphylococcus aureus that became resistant to clindamycin in vivo. Such resistance has been reported to occur in vitro, and testing for it should prove useful in proper selection of cases for treatment with clindamycin, an agent that appears to be effective in selected cases of endocarditis.
(JAMA 239:626-627, 1978)