Rapid detection of bacille Calmette-Guérin-associated mycotic aortic aneurysm using novel cell-free DNA assay

Intravesical instillation of bacille Calmette-Guérin (BCG), an attenuated strain of Mycobacterium bovis, is an adjuvant immunotherapy for bladder carcinoma. Typical complications include fever, malaise, and dysuria. However, more severe complications have been reported, including granulomatous pneumonitis, BCG sepsis, and vascular infections. We present a case of an infrarenal abdominal aortic aneurysm complicated by iliopsoas abscess 2 years after BCG treatment and discuss a novel diagnostic tool for mycobacterial strain identification.