Dysbiosis of Bile Microbiota in Cholangiocarcinoma Patients: A Comparison with Benign Biliary Diseases

Dysbiosis in the bile microbiota of cholangiocarcinoma (CCA) patients suggests a potential role for microbial alterations in the pathogenesis of CCA. This study aimed to investigate bile microbial communities in patients with CCA and compare them to those in individuals with benign biliary diseases as a control (CTR) group. Microbial profiling was conducted using next-generation sequencing (NGS), targeting the V3-V4 regions of the 16S rRNA gene, followed by bioinformatics analysis using the VSEARCH and EzBioCloud platforms. Alpha and beta diversity analyses were performed to assess microbial richness and structural differences. The linear discriminant analysis effect size (LEfSe) was utilized to identify potential microbial biomarkers. Results: This study identified distinct microbial profiles in the two groups at both the phylum and genus levels. In the CTR group, <i>Pseudomonadota</i> (65%) was the dominant phyla, while <i>Bacillota</i> (49%) was more abundant in the CCA group. At the genus level, <i>Escherichia</i> (29%), <i>Enterobacteriaceae</i> (12%), <i>Enterococcus</i> (8%), <i>Ralstonia</i> (8%), and <i>Clostridium</i> (5%) were more prevalent in the CTR group, whereas <i>Streptococcus</i> (34%), <i>Ralstonia</i> (8%), and <i>Veillonella</i> (5%) were dominant in the CCA group. Although an alpha diversity analysis showed no statistically significant differences in species richness or diversity between groups, a beta diversity analysis revealed significant structural differences associated with disease severity. Our comparative microbiome study using LEfSe analysis suggested a statistically significant inhibition of normal intestinal bacterial flora in patients with CCA who had not received any treatment. These findings suggest that microbial dysbiosis may play a role in the pathogenesis of CCA. Specific microbial taxa were identified as potential biomarkers for distinguishing benign from malignant diseases. These results underscore the potential role of microbial dysbiosis in CCA pathogenesis and highlight the bile microbiota's utility as a diagnostic marker for biliary diseases.