Cardiobacterium homonis endocarditis. Characterization of the unusual organisms and review of the literature.

A case of subacute bacterial endocarditis in which Cardiobacterium hominis was isolated from the blood of a 55-year old woman who had rheumatic heart disease is reported. A survey of the literature revealed very few reports in which this organism has been implicated in human lesions. The colonies grew after 48 hours of incubation in a candle jar. They were small, convex, nonhemolytic, and oxidase-positive. The indole reaction was positive, the catalase and nitrate reactions were negative, and acid reaction was obtained from the following carbohydrates: glucose, maltose, mannitol, sucrose, and sorbitol. The morphologic and biochemical properties served to distinguish these organisms from similar bacteria implicated in human disease, such as Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Streptobacillus moniliformis, and HB-1.