Case Report: A case study of geriatric acute cholecystitis complicated by coinfection with Shewanella putrefaciens and Enterococcus faecium

Background Acute cholecystitis is a common abdominal condition mainly caused by enteric Gram-negative bacilli and Enterococcus species. Advances in microbial detection have highlighted infections by rare pathogens like Shewanella putrefaciens ( S. putrefaciens ), an opportunistic bacterium from aquatic environments affecting mainly immunocompromised or comorbid patients. Its clinical features, antibiotic resistance, and treatment remain unclear. Case presentation This article presents a case study of an 87-year-old female patient with a medical history of gallstones and previous endoscopic retrograde cholangiopancreatography (ERCP), who was admitted to the hospital due to “low back and leg pain.” On November 14, 2023, she developed acute cholecystitis. Initial treatment consisted of cefoperazone/sulbactam and ciprofloxacin. Ultrasound-guided percutaneous transhepatic gallbladder drainage (PTGBD) was performed, revealing purulent bile that tested positive for S. putrefaciens and Enterococcus faecium ( E. faecium ). Based on susceptibility testing, the antibiotic regimen was adjusted to cefoperazone/sulbactam and vancomycin, which was administered until November 24, 2023. The patient’s condition subsequently improved, and she was discharged from the hospital. Conclusion We documented the inaugural case of an elderly patient presenting with acute cholecystitis co-infected with S. putrefaciens and E. faecium . This case underscores the importance of integrating source control via PTGBD with targeted antimicrobial therapy guided by drug susceptibility testing, highlighting their synergistic role in effective management. Furthermore, the monitoring of procalcitonin (PCT) levels offers valuable support for clinical decision-making.