Unusual Localization of Presumptive Sarcina ventriculi in the Terminal Ileum: A Case Report

Sarcina ventriculi is a bacterium predominantly reported in the stomach and associated with emphysematous gastritis, delayed gastric emptying, gastroparesis, or gastric outlet obstruction. Its prevalence is increasing among patients with a history of organ transplants, immunosuppression, and graft-versus-host disease (GVHD). This bacterium can be detected on histology with characteristic tetrad packet morphology; however, confirmation requires PCR and molecular studies. The role of Sarcina ventriculi in human diseases is not fully understood and has unclear clinical significance. While certain studies point to a possible pathogenic role, others regard its detection as incidental with no clear clinical consequence.

Herein, we report a case of a 39-year-old male patient with primary refractory cHL, stage IVb, who underwent an autologous bone marrow transplant (BMT) and an allogeneic stem cell infusion. His post-transplant course was complicated by chronic kidney disease (CKD), malnutrition, depression, myopathy, skin, and colon GVHD. He eventually developed sepsis, was admitted to the ICU and developed multiorgan failure and passed away. The patient developed diarrhea, and the gastrointestinal specialist was consulted and revealed ulcerated ileitis and colitis. Biopsies were taken to evaluate for CMV infection and GVHD. The terminal ileum biopsy mainly revealed ulceration with granulation tissue formation and abundant microorganisms arranged in distinctive tetrads, characteristic of Sarcina ventriculi. The colonic biopsies were consistent with GVHD grade II.

The significance of Sarcina microorganisms and their mechanisms of injury remain poorly understood. The identification of Sarcina ventriculi in the terminal ileum, which is an unusual and previously unreported finding, adds a new perspective to our understanding of its pathogenic potential and anatomical distribution. While the patient's clinical decline was influenced by multiple factors, including GVHD, recurrent sepsis, and multiorgan failure, the role of Sarcina ventriculi as a potential exacerbating factor remains unclear.