2022 Volume 55 Issue 7 Pages 447-452
The patient was a 57-year-old male, who had been undergoing hemodialysis for 10 years. When he was admitted to our hospital to undergo parathyroidectomy, he had a slight fever (37℃), and his serum C-reactive protein level had been elevated for several months. The findings of chest X-rays and chest and abdominal computed tomography were not remarkable, and no vegetation was detected on the cardiac valves by transthoracic echocardiography (TTE). Several sets of blood cultures were negative. He underwent TTE again during his hospitalization, and it showed vegetation on the aortic valve. We suspected infective endocarditis and started antibiotic therapy. However, because the vegetation had increased in size and become unstable, aortic valve replacement was performed. A pathological examination showed valve destruction and that inflammatory cells had infiltrated into the valve tissue. Furthermore, long-term cultures of aortic valve tissue were found to be positive for Propionibacterium acnes (P. acnes). P. acnes is part of the normal flora of the skin and oral cavity, but rarely causes infective endocarditis. In addition, it is difficult to detect P. acnes using standard blood cultures alone. Clinicians should be aware that that infective endocarditis in hemodialysis patients may be caused by unusual bacteria that are hard to isolate from standard blood cultures.