Delayed Cutibacterium acnes infection of a thoracic aortic graft presenting as empyema: A case report and literature review.

Cutibacterium acnes is a low-virulence skin commensal that can cause late-onset prosthetic graft infections. We report the case of a 60-year-old man with diabetes who presented with fever and bilateral chest pain 10 months after an ascending aortic graft replacement. Computed tomography revealed right-sided pleural effusion and perigraft fluid collections; extended incubation of the pleural fluid and blood samples revealed C. acnes. Seven weeks after the intravenous antibiotic therapy, the patient underwent mediastinal irrigation, explantation of the infected graft, replacement with a rifampicin-soaked prosthesis, and omental flap coverage. Extended incubation of intraoperative specimens resulted in C. acnes in both samples. Following four additional weeks of intravenous antibiotic therapy, long-term oral amoxicillin suppression was initiated. At one-year follow-up, the patient remained clinically stable without evidence of recurrence. This case highlights the importance of extended incubation, vigilant diagnostic evaluation, and combined surgical and antimicrobial management in delayed C. acnes vascular graft infections. We also reviewed relevant literature on C. acnes prosthetic vascular infections to contextualize this case.