Related Experiment Video
Updated: May 26, 2026

Growth of Mycobacterium tuberculosis Biofilms
Published on: February 15, 2012
Mycobacterium fortuitum prosthetic valve endocarditis: a case for the pathogenetic role of biofilms
Silvia Bosio1, Surbhi Leekha, Scott I Gamb
1Division of Anatomic Pathology, Mayo Clinic, Rochester, MN, USA.
Background:
Prosthetic valve endocarditis presents unique challenges for both diagnosis and treatment. A potential role of biofilm has been hypothesized in the pathogenesis of these infections.
Methods:
A patient with infective endocarditis involving a stentless (Freestyle) porcine prosthetic aortic valve with annular abscess and paravalvular leak 8 months after implantation is reported.
Results:
The infected valve did not show vegetations or perforations, but histiocytic inflammation was seen along the endocardial surfaces of the valve. Auramine-rhodamine staining revealed many acid-fast organisms associated with the inflammation. There was also an acellular matrix material with ultrastructural features of biofilm. Blood cultures grew Mycobacterium fortuitum, a biofilm-associated microbe.
Conclusions:
The role of biofilm in prosthetic valve endocarditis is discussed. The importance of microscopy for prosthetic valves, even when no vegetations are present, is highlighted along with correlation of pathologic findings with culture results.
Related Concept Videos
Endocarditis I: Introduction
Biofilms
Endocarditis III: Medical Management
Endocarditis II: Clinical Features of Infective Endocarditis
Colonisation of Pathogens
Bacterial Meningitis II: Pathophysiology

