Endocarditis due to an atypical mycobacterium following porcine heart valve replacement.

Following aortic valve replacement with a porcine xenograph, a patient developed endocarditis complicated by a fistula between aorta and right ventricle. The xenograph was replaced by a mechanical valve and the fisutla oversewn. No organisms were cultured but acid-fast bacilli were seen in the aortic wall and excised valve tissue. It is likely that these were contaminants of the porcine prosthesis.