A surgical case of mycotic aneurysm with Staphylococcus lugdunensis endocarditis

A 74-year-old man with a history of mitral valve repair was referred to our hospital with fever and diagnosed with mitral valve endocarditis involving occlusion of the superior mesenteric artery. Bacterial cultures showed Staphylococcus lugdunensis. Despite antibiotic therapy, orthopnea ensued due to valve destruction. Emergency mitral valve replacement was performed. Computed tomography on postoperative day 10 revealed a rapidly expanding mycotic aneurysm of the superior mesenteric artery. Aneurysmectomy was undertaken. Mycotic aneurysms of the superior mesenteric artery have not been reported previously in association with Staphylococcus lugdunensis. A rapid diagnosis and prompt surgical intervention are necessary for rescue.