Endocarditis caused by Actinomyces viscosus.

A case of severe endocarditis caused by Actinomyces viscosus is described in a previously healthy 70-year-old man. The isolated strain has been characterized by biochemical tests, gas-liquid chromatography and serology. The pathogenic significance of the organism is discussed and the difficulty in reaching a correct diagnosis due to the similarity to species of Corynebacterium is pointed out.