Actinobacillus actinomycetemcomitans endocarditis in a patient with a prosthetic aortic valve.

Bacterial endocarditis caused by Actinobacillus actinomycetemcomitans is a rare disease. A 48-year-old man who had a Starr-Edwards aortic valve prosthesis inserted in 1972 was admitted for evaluation of confusion, headaches, anorexia, weight loss, diarrhea and weakness. Six blood cultures yielded gram-negative organisms which were subsequently identified as A. actinomycetemcomitans. Treatment with ampicillin and gentamicin resulted in cure which has been maintained after an observation period of eleven months. This represents the second report of A. actinomycetemcomitans endocarditis in a patient with a prosthetic valve.