Microbiological profile of bile in patients undergoing cholecystectomy and its association with surgical site infection

Background

Bile is usually sterile under physiological conditions; however, gallstone disease and biliary stasis may lead tobacterial colonisation. Bactibilia may act as an endogenous source of surgical site infection after cholecystectomy. Thisstudy evaluated the microbiological profile of bile in patients undergoing cholecystectomy and assessed its association withpostoperative surgical site infection. Materials and Methods: This prospective observational study included 90 adultpatients undergoing elective or emergency cholecystectomy at Hind Institute of Medical Sciences, Barabanki. The studyduration was 18 months. Intraoperative bile samples were collected under aseptic precautions and subjected to Gramstaining, aerobic culture, anaerobic culture, organism identification and antimicrobial susceptibility testing. Patients werefollowed for 30 days postoperatively for surgical site infection using CDC criteria and Southampton wound grading.Results: The mean age of the study population was 45.2 ± 13.8 years. Females constituted 78 patients (86.67%) and males12 patients (13.33%). Laparoscopic cholecystectomy was performed in 81 patients (90.00%) and open cholecystectomy in 9patients (10.00%). Bile culture was positive in 31 patients (34.44%). Klebsiella pneumoniae was the most common biliaryisolate, identified in 12 cases (38.71%), followed by Pseudomonas spp. and Staphylococcus aureus in 6 cases each (19.35%).Gram-negative biliary isolates showed highest sensitivity to imipenem in 23 cases (92.00%) and amikacin in 22 cases(88.00%), while ceftriaxone resistance was seen in 15 cases (60.00%). Surgical site infection developed in 12 patients(13.33%). SSI occurred in 10 of 31 patients with positive bile culture and in 2 of 59 patients with sterile bile culture,showing a significant association between bactibilia and SSI (χ² = 16.8, p < 0.001). Bactibilia was the strongest independentrisk factor for SSI on logistic regression (OR 4.80, 95% CI 2.05–11.2, p < 0.001).