To the Editor.—
Listeria monocytogenes endocarditis has been reported, to the best of our knowledge, only 14 times in the world literature. We describe the successful treatment of this entity with penicillin G potassium alone.
Report of a Case.—
A 55-year-old man was admitted to Ohio State University Hospital in June 1976. He was known to have rheumatic heart disease with mitral stenosis and aortic insufficiency. He had had fever for six weeks. Blood cultures grew L monocytogenes in three of three bottles. The patient became afebrile shortly after therapy was begun with penicillin G potassium, 2 million units every two hours. Studies of serum antibacterial activity before and after penicillin administration disclosed that a 1:128 dilution of serum yielded a 90% kill in vitro. The patient remained afebrile and was discharged on the 41st hospital day.Antibiotic synergism studies were done by the standard checkerboard microtiter technique. Modest synergism