Prosthetic valve endocarditis caused by a very rare black mold, Exophiala dermatitidis

Prosthetic valve endocarditis (PVE) caused by Exophiala dermatitidis is an exceedingly rare and diagnostically challenging condition. We present the case of a 62-year-old male who developed fungal PVE 18 months post-aortic valve replacement (AVR) with a bioprosthetic valve. The patient exhibited persistent low-grade fever and dyspnea, with transesophageal echocardiography (TEE) revealing large vegetations and an aortic annular abscess. Despite sterile blood cultures, intraoperative findings of black, friable vegetations prompted empirical antifungal therapy. Nanopore sequencing rapidly identified Exophiala dermatitidis, facilitating targeted dual antifungal treatment with voriconazole and liposomal amphotericin B. This case highlights the importance of early surgical intervention, molecular diagnostics, and combination antifungal therapy in managing fungal PVE caused by E. dermatitidis, emphasizing the need for heightened clinical suspicion and multidisciplinary approaches for improved patient outcomes.