A Case of Colorectal Cancer Detected by Vascular Graft Infection Caused by Listeria Monocytogenes

Listeria monocytogenes is a rare etiology of graft infection, with only 17 cases reported previously in the literature. Herein, we present a rare case of aortic arch graft infection caused by L. monocytogenes, in which workup of the patient for the infection revealed colorectal cancer.The patient was an elderly man with a history of total aortic arch replacement and type 2 diabetes mellitus who presented to us with a several weeks' history of persistent chest and back pain and was hospitalized. Diagnostic work-up indicated an infection of the aortic arch graft. Blood cultures were positive for L. monocytogenes. Prompt relief of pain and improvement in inflammatory marker levels were observed following antibiotic therapy using ampicillin (ABPC) and gentamicin (GM) in combination. A fecal occult blood test conducted for screening was positive. Subsequent upper and lower gastrointestinal endoscopy revealed colorectal cancer, which was treated by laparoscopic surgery. As there was no evidence of metastasis, postoperative chemotherapy was deemed unnecessary. ABPC was administered continuously for a total of 6 weeks, along with administration of amoxicillin (AMPC) for 6 months. The infection was successfully controlled with the long-term antibiotic therapy and there has been no recurrence since.