Caucasian female patient aged 53 years with COPD, diabetes, hypertension, anxiety, and depression presented with right upper quadrant pain, and leukocytosis. Ultrasound confirmed acute cholecystitis. Bile duct was of normal size and liver function tests were normal.

Patient was taken to the operating room for an urgent laparoscopic cholecystectomy. Third day post-surgery, patient has no health complaints, an ultrasound check-up was performed and after no free abdominal fluid was identified, abdominal drainage catheter was removed. Patient was discharged with recommendations for antibiotic treatment.

However, 8 days upon discharge patient had postoperatively persistent right upper quadrant pain radiating to the epigastrium and fever.

Physical examination disclosed no abnormalities except for mild RUQ tenderness and fever (98.6 °F, 37 °C). Blood analyses revealed mild elevation of total bilirubin (2.1 mg/dL) and increased serum inflammation markers (ESR, CRP and fibrinogen); there were leukocytosis with polymorphonuclearcytosis and other laboratory studies including liver and pancreas function tests were within normal limits. Upper abdomen US scan revealed moderate nonspecific perihepatic and peripancreatic fluid containing some echogenic spots, without any significant biliary dilatation. Which of the following is the most likely cause of this patient’s current condition?