Lelliottia amnigena bacteremia in a patient with sigmoid colon cancer and schizophrenia: a case report

Lelliottia amnigena is a facultative anaerobe that is generally considered to show low pathogenicity, and few reports have described human infection. We describe herein a case of bacteremia due to L. amnigena in a patient with sigmoid colon cancer and schizophrenia. A 64-year-old Japanese man with schizophrenia was transferred to our hospital from a psychiatric hospital after experiencing several weeks of bloody bowel discharge and fever. He presented with hypotension, an elevated white blood cell count, raised levels of C-reactive protein, and decreased hemoglobin levels. Blood culture on transfer to our hospital detected Gram-negative rods, identified as L. amnigena by matrix-assisted laser desorption/ionization mass spectrometry and 16S rRNA gene sequencing. Antimicrobial therapy was initiated with piperacillin/tazobactam, which was later de-escalated to ampicillin/sulbactam according to the results of antimicrobial susceptibility testing, resulting in a total of 14 days of antimicrobial treatment. Computed tomography and colonoscopy revealed that the patient had sigmoid colon cancer, which was subsequently surgically resected. The sigmoid colon cancer was considered to represent the gateway for L. amnigena entry into the bloodstream. The course of treatment was favorable and the patient was transferred back to the original hospital 98 days after admission. L. amnigena bacteremia has rarely been reported, and the present case appears to represent the first detailed description. L. amnigena can cause bacteremia and sometimes lead to serious conditions in patients.