Brown-Pigmented Mycobacterium mageritense as a Cause of Prosthetic Valve Endocarditis and Bloodstream Infection.

Mycobacterium spp. are a rare cause of endocarditis. Herein, we describe a case of Mycobacterium mageritense prosthetic valve endocarditis. This organism produced an unusual brown pigment on solid media. Cultures of valve tissue for acid-fast bacilli might be considered in some cases of apparently culture-negative prosthetic valve endocarditis.