Infection Due toActinobacillus actinomycetemcomitans

Abstract

Actinobacillus actinomycetemcomitans, an unusual Gram-negative coccobacillus, was isolated from the blood cultures of two patients. One patient with multiple myeloma and pneumonia was successfully treated with ampicillin. The other, with bacterial endocarditis, but without a previous history of heart disease, responded to kanamycin therapy. Endocarditis caused by this organism is frequently complicated by cerebral embolization. This bacterium may be overlooked in blood cultures because of its slow growth and requirement for 5% CO₂ when subcultured on solid agar media.