S3595 An Unusual Culprit in Cholecystitis: R. ornithinolytica in a Cirrhotic Patient

Introduction: Raoultella ornithinolytica is a Gram-negative, encapsulated, non-motile bacillus of the Enterobacteriaceae family, previously classified within the Klebsiella genus. Although increasingly recognized as a human pathogen, R. ornithinolytica remains rare and is most often associated with biliary infections, particularly in malignancy. We describe a cirrhotic patient with acute cholecystitis and R. ornithinolytica bacteremia managed via percutaneous transhepatic cholecystostomy (PTC). Case Description/Methods: A 49-year-old man with compensated alcoholic cirrhosis (abstinent 10 years) presented with right upper quadrant (right upper quadrant) pain, nausea, vomiting, fever, and chills. Exam showed right upper quadrant tenderness and a positive Murphy’s sign. Labs revealed lactic acidosis (3.4 mmol/L), cholestatic pattern (AST 64 U/L, ALT 77 U/L, ALP 138 U/L), leukopenia (WBC 2.8 × 10³/µL), thrombocytopenia (81 × 10³/µL), and anemia (Hb 11.2 g/dL). US showed gallbladder distention with sludge and hepatomegaly. Intravenous fluids, analgesia, and broad-spectrum antibiotics were started. Blood cultures grew R. ornithinolytica sensitive to third-generation cephalosporins; antibiotics were narrowed to ceftriaxone and metronidazole. By day 2, platelets declined to 41 × 10³/µL with new hematuria and persistent right upper quadrant pain. Computed tomography showed cirrhosis, splenomegaly, and unchanged gallbladder findings. HIDA confirmed cystic duct obstruction. Surgery deferred cholecystectomy due to thrombocytopenia; US-guided PTC was placed. The patient improved and was discharged on day 7 with a cholecystostomy tube and 7-day oral cefuroxime and metronidazole. Four weeks later, he re-presented with right upper quadrant discomfort and change in catheter output to orange-brown, concerning for acute-on-chronic cholecystitis. Intravenous antibiotics were restarted. Imaging showed no obstruction; blood cultures were sterile. The tube was removed per surgical advice. He was counseled on chronic cytopenias and declined HIV testing. He improved and was discharged. Discussion: This case highlights R. ornithinolytica’s ability to cause severe cholecystitis with bacteremia. Cirrhosis and thrombocytopenia complicated surgical management, necessitating percutaneous intervention. As an emerging pathogen, it should not be dismissed as a contaminant. Its potential for community-acquired infection and drug resistance poses a serious sepsis risk. To our knowledge, this is one of few reported cases successfully managed with cholecystostomy. Awareness of its pathogenicity is essential in high-risk patients.