Listeriosis in an immunocompetent patient after diagnostic colonoscopy

We present an 80-year-old female with type II diabetes (well controlled) who presented to the emergency department with a hemoglobin of 6.5 mg/d consistent with iron deficiency anemia (IDA). As part of the workup for IDA, she had an esophagogastroduodenoscopy (EGD) and colonoscopy. EGD was unremarkable. Colonoscopy revealed a mass occupying about 50% of the circumference of her descending colon suspicious for malignancy, which was biopsied. Thirty-six hours later, she developed fevers; blood cultures grew Listeria monocytogenes. Workup to identify the source of bacteremia was negative for other sources of infection. Due to the temporal relationship, the development of bacteremia was attributed to the disturbance of the gastrointestinal tract possibly from recent biopsy of the colonic mass. She was treated with penicillin for a total of about 4 weeks with complete resolution of symptoms and clearance of bacteremia. She had a transverse colectomy 6 weeks later with surgical pathology of the lesion showing intramucosal adenocarcinoma. This case represents a rare complication of colonoscopy and is novel because our patient was not immunocompromised as previously reported in other cases.