Analysis of biliary pathogens and clinical characteristics in patients with biliary tract infections based on a history of biliary-enteric bypass: a single-center retrospective study

BACKGROUND: Biliary‒enteric bypass surgery, while relieving obstruction, disrupts the anatomical barrier of the biliary system, predisposing patients to biliary infections. However, comprehensive comparative analyses of biliary pathogen profiles, inflammatory responses, antimicrobial resistance and clinical characteristics in patients with and without a history of this surgery are limited. This study aimed to compare these aspects and their impact on clinical characteristics between these two patient groups. METHODS: A single-center retrospective study was conducted on 74 patients who underwent percutaneous transhepatic biliary drainage (PTBD) for biliary tract infections between October 2020 and May 2024. Patients were divided into biliary-enteric bypass (n = 32) and nonbypass (n = 42) groups on the basis of surgical history. Data on demographics, bile cultures, inflammatory markers, antibiotic use, and multidrug-resistant organism (MDRO) were analysed. RESULTS: The bypass group had a significantly higher bile culture positivity rate (78.1% vs. 45.2%, p < 0.01; adjusted OR = 4.1, 95% CI: 1.5–11.2), with a predominance of Escherichia coli (34.4%) and Enterococcus faecium (21.9%). The MDRO infection rate was markedly higher in the bypass group (46.9% vs. 21.4%, p = 0.01; adjusted OR = 3.3, 95% CI: 1.2–9.1), accompanied by higher use of carbapenems (25.0% vs. 18.8%, p = 0.04). Preoperative inflammatory marker levels were significantly elevated in the bypass group (p < 0.01). Clinically, the bypass group experienced longer hospital stays (28.5 vs. 25.7 days, p = 0.04), a higher rate of treatment failure (31.3% vs. 11.9%, p = 0.04; adjusted OR = 3.5, 95% CI: 1.1–11.3), and higher total costs (8.9 vs. 7.6, p = 0.02) (ten thousand CNY). CONCLUSION: A history of biliary-enteric bypass is associated with a distinct and more severe biliary infection profile characterized by higher rates of bacterial colonization, MDROs, intense systemic inflammation, increased carbapenem reliance, and poorer clinical outcomes, including longer hospitalization, higher treatment failure rates, and increased costs.