Zoonotic aortic graft infection by Streptococcusequi

A 69-year-old woman with hypertension had undergone total arch replacement with an open stent graft 7 years prior. She was referred to our hospital for evaluation after experiencing fever (>38 °C) and cough. Chest radiography revealed a prominent aortic arch, and contrast-enhanced computed tomography demonstrated aortic arch enlargement and peri-graft fluid collection containing air. These findings indicated graft infection and prompted immediate intervention. Blood cultures grew Streptococcus equi subspecies zooepidemicus, a zoonotic pathogen associated with horses. Notably, the patient worked as a horse trainer. On hospital day 6, she developed severe hemoptysis due to an aortobronchial fistula caused by stent graft infection and underwent emergency re-replacement of the aortic arch. Intraoperative specimens also yielded the same pathogen. Consequently, she was treated with ampicillin, and her postoperative course was uneventful. Although rare, zoonotic pathogens can cause vascular graft infections.