Mycotic Abdominal Aortic Aneurysm Caused by Streptococcus equi

Streptococcus equi is a bacterium common in equine species and an uncommon pathogen in humans. Reported human infections can be severe and include meningitis, septic arthritis, and endocarditis. We report the case of a 64-year-old male who S. equi with several months of constitutional symptoms, back pain, and abdominal pain. Imaging demonstrated a large abdominal aortic aneurysm with a contained retroperitoneal rupture, with cultures from the aneurysm and blood cultures both positive for S. equi. The patient was successfully treated with open repair and placement of a Dacron graft and intravenous antibiotics and will remain on lifelong antibiotic prophylaxis.