Microbiological assessment of bile in patients after endoscopic retrograde cholangio-pancreatography (ERCP): The “MICROBILE” registry

BACKGROUND: Microbial communities were recently revealed in the biliary tract of pancreaticobiliary disorders. However, evidence is limited and comparative data are lacking. AIMS: We aimed to characterize the biliary microbiota in patients with naïve papilla affected by obstructive jaundice eligible for endoscopic treatment. METHODS: 222 consecutive patients undergoing ERCP were prospectively enrolled from July 2022 to August 2023. Bile was sampled before and after sphincterotomy,then stored for cultures and resistance profiles. RESULTS: Pre-sphincterotomy (66,6%) and post-sphincterotomy samples (67,5%) revealed bacterial growth, with similar components. Gram-positive bacteria, as Enterococcus spp, were mainly identified. Age ≥60 years, Charlson Comorbidity Index (CCI) ≥4, fever, ongoing antimicrobial therapy and positive blood cultures were associated with positive bile cultures. Positive C-reactive protein was independently related to positive cultures. Multidrug Resistand (MDR) strains, according to international standardized definition, were detected (18%), with a higher prevalence of ESBL bacteria and E. faecium VRE. Antimicrobial therapy was an independent risk factor for MDR biliary bacteria in the multivariate analysis. Positive cultures, polymicrobial flora, and MDR bacteria were similar in malignant and benign disease. CONCLUSION: Multiple clusters and MDR bacteria were detected in patients with obstructive jaundice. We identified clinical and biochemical risk factors for bacteriobilia and MDR commensals.