Endarteritis and mycotic aortic aneurysm caused by an oral strain of Actinobacillus actinomycetemcomitans.

Actinobacillus actinomycetemcomitans was isolated from blood cultures of a 33-year-old febrile patient with a previously undiagnosed coarctation of the aorta. Subgingival samples from diseased periodontal pockets revealed the presence of A. actinomycetemcomitans. An infected (mycotic) aortic aneurysm and endarteritis were diagnosed and surgically treated. The identity of blood and oral clinical isolates of A. actinomycetemcomitans was supported by genetic analysis, including fingerprinting by restriction fragment length polymorphism, ribotyping, and random amplified polymorphic DNA; biotyping; and antibiogram typing. These data strongly suggest that the periodontal pockets were the primary source of A. actinomycetemcomitans endarteritis in this case.