Culprit or Innocent Bystander? A Case of Hematemesis

**Background:** Sarcina ventriculi is a Gram-positive anaerobic coccus with a birefringent cellulose coating, averaging 1.8 to 3 μm in size, found in water and soil that thrives in low pH environments. In the stomach, it appears as clusters of tetrads with characteristic flattening of cell walls at points of contact. Its metabolism is strictly carbohydrate dependent. The pathogenic role of S. ventriculi remains unclear, but it has been associated with gastroparesis, gastric ulcers, mucosal inflammation, emphysematous gastritis, gastric perforation, and esophagitis. Local accumulation of acetaldehyde and ethanol from carbohydrate fermentation by S. ventriculi may cause gastric mucosal injury. The most common endoscopic feature is food retention due to delayed gastric emptying, often accompanied by an inflamed gastric mucosa.

**Methods:** This is a single case report of an 11-year-old previously healthy female who presented with a 1-year history of generalized abdominal pain, early satiety, and intermittent hematemesis without history of melena. She underwent esophagogastroduodenoscopy (EGD) as part of her diagnostic workup.

**Key Results:** EGD was notable for diffuse gastric erythema and retained food in the stomach despite being nil per os for solid food for 14 hours. Histopathologic examination showed chronic gastritis in the gastric body and focal organisms identified morphologically as Sarcina ventriculi. The organisms demonstrated characteristic morphology: aggregates of basophilic stained, cuboid organisms in tetrad packet arrangement with flattening of the cell walls in areas of contact with adjacent cells. The child received empiric treatment with metronidazole and amoxicillin/clavulanic acid for 1 week along with a proton-pump inhibitor for 2 weeks.

**Clinical Implications:** There is currently no consensus on which patients need treatment for S. ventriculi colonization, nor are there guidelines regarding antibiotic selection or duration of treatment. In this case, the empiric treatment regimen resulted in resolution of hematemesis and improvement of abdominal pain. This case highlights S. ventriculi as a potential pathogen in pediatric patients with gastritis and hematemesis, though its exact pathogenic role remains uncertain. The presence of retained food on endoscopy after appropriate fasting should raise suspicion for S. ventriculi infection, particularly in the setting of delayed gastric emptying and inflamed gastric mucosa.