Here we describe a case involving an elderly man with Citrobacter freundii-associated infectious rupture of a dissecting thoracoabdominal aortic aneurysm. We performed emergency thoracoabdominal aortic replacement using a rifampicin-soaked prosthetic graft and omental flap wrapping. The patient was discharged on postoperative day 255, although he experienced pseudomembranous enteritis and paraplegia.