Infective endocarditis caused by Chaetomium globosum

Chaetomium globosum is a dematiaceous, filamentous fungus belonging to the large genus saprobic ascomycetes and is rarely involved in human infection. We present the case of a 25-year-old man undergoing tricuspid valve replacement due to recurrent prosthetic ring endocarditis. Initially, it was considered culture-negative endocarditis; however, the diagnosis of Chaetomium globosum could only be provided by DNA isolation of the mold isolate grown in culture and the valve tissue samples taken from the patient. This report describes the first documented tricuspid endocarditis caused by Chaetomium species and discusses the importance of molecular tools to enhance the diagnostic process in culture-negative endocarditis, especially for fastidious and nonculturable microorganisms.