Prosthetic graft infections with mediastinitis following aortic surgery are rare, yet represent grave complications yielding high morbidity and mortality. We present the case of a 57-year-old female patient with past history of emergent surgery for iatrogenic Type A dissection treated by supracoronary ascending aortic replacement. Four months after the initial surgery, a sternal fistula had formed and due to severe bleeding emergent reoperation was required. Imaging and pathology on admission revealed an infected pseudoaneurysm at the distal aortic prosthesis and mediastinitis with met hicillin-resistant Staphylococcus aureus. Rescue surgery was performed by means of a two-stage approach, with extensive debridement, graft replacement and continuous antiseptic lavage in a first step and an omental wrapping of the new prosthesis in a second stage 24 hours later. During 10 years of follow-up, no recurrent infection occurred. The operative approach and general considerations for management of infected pseudoaneurysms are discussed.