The article describes the case of an 87-year-old female patient with a history of gallstones and previous ERCP, admitted on November 14, 2023 due to low back and leg pain, who developed acute cholecystitis. Initial treatment included cefoperazone/sulbactam and ciprofloxacin. They performed ultrasound-guided percutaneous transhepatic gallbladder drainage (PTGBD), which revealed purulent bile positive for Shewanella putrefaciens and Enterococcus faecium. Based on the antibiotic sensitivity test, they adjusted the treatment to cefoperazone/sulbactam and vancomycin, administered until November 24, 2023. The patient's condition improved and she was discharged from the hospital. This is the first documented case of geriatric acute cholecystitis with coinfection with these bacteria. It emphasizes the importance of PTGBD and targeted antibiotic therapy according to susceptibility tests, as well as procalcitonin monitoring for clinical decision-making.