Exploring the biliary microbiome in hepatopancreatobiliary disorders: a comprehensive systematic review of microbial signatures and diagnostic potential.

BACKGROUND: Hepatopancreatobiliary (HPB) diseases, encompassing hepatobiliary and pancreatic disorders, pose substantial global health challenges due to their high morbidity and mortality rates. Recent research highlights the crucial role of the biliary microbiome in the development of these diseases. METHODS: This study provides a comprehensive systematic review of the biliary microbiome's characteristics across various HPB disorders, including cholangiocarcinoma (CCA), pancreatic cancer (PC), primary sclerosing cholangitis (PSC), and gallstone disease (GSD). Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we screened articles from multiple databases, focusing on original research utilizing 16 S rRNA gene sequencing or metagenomics. RESULTS: Our review included 24 studies that met stringent inclusion criteria. The results indicate distinct alterations in bacterial diversity and composition associated with different HPB conditions, highlighting potential pathogenic mechanisms and candidate taxa as potential microbial indicators. In lithiasis conditions, elevated levels of Pyramidobacter and Citrobacter were associated with recurrent and giant common bile duct (CBD) stones. Proteobacteria were prevalent in PSC and CCA, potentially contributing to these diseases by promoting chronic inflammation. Sphingomonas was associated with both CCA and PSC, with potential implications for lymph node metastasis in PC. CONCLUSIONS: These findings suggest the potential of the biliary microbiome as a diagnostic tool, offering insights into the pathophysiology and possible therapeutic targets for HPB diseases. However, given the heterogeneity in methodologies and the limited number of studies including healthy controls, these observations remain preliminary; further prospective validation is required before clinical translation.