Mycobacterium Chimaera an Unusual Cause of Mitral Valve Endocarditis
Matthias Roessle, Yvonne Achermann, Dieter Zimmermann, Barbara Hasse, Vanessa Deggim, Matthias Hoffmann, Jurg Grunenfelder, Michael Hombach. University Hospital Zurich, Zurich, Switzerland; University of Zurich, Zurich, Switzerland; Cantonal Hospital St. Gallen, St. Gallen, Switzerland
Background: Mitral valve endocarditis (MVE) is mostly caused by bacterial or fungal infections. Only in rare cases non-tuberculous mycobacteria (NTM) were detected as causative agents. Here we present the first case of MVE caused by Mycobacterium chimaera.
Design: A 58 years old man with diagnoses of systemic sarcoidosis, therefore receiving steroids, and monoclonal gammopathy of undetermined significance underwent mitral and aortic valve replacement due to severe valve insufficiency. Histological and molecular analyses of mitral valve tissue were performed.
Results: Histologically, there is a partly necrotizing, acute and chronic inflammation of fibrous valve tissue with numerous swollen macrophages containing many PAS- and acid-fast-positive bacteria. Molecularbiological analysis of the FFPE tissue showed mycobacterial DNA of the M. avium complex. Subsequent microbiological analysis of the mitral valve annulus, blood cultures, and sputum allowed identification of M. chimaera DNA.
Conclusions: We report the first case, in which M. chimaera was identified as causative agent of endocarditis in a patient with hitherto unknown disseminated NTM-infection.
As - like in our case - NTM-associated endocarditis shows morphological characteristics of NTM-infection of other organs, it is recommended to perform special stains like PAS and Ziehl-Neelsen to highlight the acid-fast bacteria. Subsequent molecular- and microbiological analyses usually allow identification of the mycobacterium species.
Wednesday, March 21, 2012 1:00 PM
Poster Session VI # 260, Wednesday Afternoon