Changes in biliary microbiota before and after drainage of malignant biliary obstruction

Background he biliary system stores bile for fat digestion and nutrient absorption. Surgery or other changes can disrupt this system, altering the microbiome and potentially leading to complications. Such disruptions may impact patient outcomes, highlighting the need for careful monitoring during biliary drainage procedures. Aims To investigate changes in biliary microbiota before and after MBO drainage and assess the impact on microbiota. Methods In this retrospective study, 42 MBO patients underwent percutaneous transhepatic catheter drainage (PTCD) from January 2020 to December 2022. The cohort included patients with cholangiocarcinoma, pancreatic cancer, hepatocellular carcinoma, and hilar lymph node metastasis. Bile samples were collected before and 7 days after drainage, analyzed using culture and next-generation sequencing (NGS). Data on acute cholangitis and antibiotic use were also collected. Results Prior to drainage, common bacteria included Burkholderia, Acinetobacter, Pseudomonas, and Staphylococcus, similar to normal biliary microbiota. Post-drainage, there was a notable increase in Staphylococcus, Klebsiella, and other pathogens, along with a decrease in microbial diversity and evenness. Conclusion In MBO patients, the biliary microbiota resembles that of non-diseased ducts but significantly changes post-drainage. There is increased pathogenic bacteria and reduced diversity, explaining the higher infection risk.