Streptococcus pasteurianus Mycotic Aneurysm of the Left Common Iliac Artery: Uncommon Manifestation of an Unusual Pathogen

1Division of Infectious Diseases and Tropical Medicine, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand. 2Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand. Received for publication: May 23, 2011. Reprint request: Methee Chayakulkeeree, M.D., Ph.D., Division of Infectious Diseases and Tropical Medicine, Department of Medicine, Faculty of Medicine Siriraj Hospital, 2 Prannok Road, Bangkoknoi, Bangkok 10700, Thailand. E-mail: [email protected] INTRODUCTION Mycotic aneurysm is a rare medical condition but can be life-threatening. Even with a combination of surgical and antimicrobial therapy, the mortality rate is as high as 16-44%.1-2 The most common pathogens causing mycotic aneurysm include Staphylococcus aureus,1-5 nonthyphoidal Salmonella spp.,2-6 and Burkholderia pseudomallei.7 Although ABSTRACT We report a case of 64-year-old diabetic man presented with a gradual-onset left hip pain for one week followed by high grade fever and progressive abdominal pain at left lower quadrant region with an equivocal peritoneal irritation sign. Computed tomography of abdomen revealed a mycotic aneurysm of the left common iliac artery with surrounding fluid collection, subsequently diagnosed as concealed rupture of mycotic aneurysm. His blood culture grew Streptococcus pasteurianus and high-dose penicillin G sodium was administered as a specific treatment. He was successfully treated with intravascular stent graft insertion and femoro-femoral crossover bypass. Echocardiography showed no vegetation. He was complicated by bilateral psoas abscesses, spondylodiscitis, epidural abscess and recurrent pseudoaneurysm of both common iliac arteries resulting in arterial bypass surgery. After a 69-day admission, he was improved and discharged from the hospital. To our knowledge, this is the first case of left common iliac artery infection caused by S. pasteurianus. (J Infect Dis Antimicrob Agents 2011;28:183-90.)