Cholangiocarcinoma remain as a fetal gastrointestinal cancer .Environmental factors including microbiota may influence on its development. by the way there is no confirmatory study in this regard.In present study We try to characterizing the biliary microbiota in CCA patients in order to identify a specific CCA-related dysbiosis.

In a prospective study, the biliary effluents were collected through an endoscopic retrograde pancreatic cholangiography (ERCP) examination. involving 28 CCA and 47 patients with gallstones, herein considered as controls. The clinical and lab data gathering by a questionnaire .The collected specimens were frozen in -80c and transfer to a research lab in France . The biliary effluents were submitted to bacterial DNA extraction and 16S rRNA sequencing, using Illumina technology.

Principal coordinate analysis (PCoA) detected a significant disparity of biliary microbiota composition between CCA patients and controls without an associated disease. Amongst the most abundant phyla, Proteobacteria did not significantly differ between CCA patients and controls, whereas Firmicutes levels were lower and Bacteroidetes higher in CCAs’ biliary microbiota than in the controls’ microbiota. The most abundant genera were Enterococcus, Streptococcus, Bacteroides, Klebsiella, and Pyramidobacter in CCA’s biliary microbiota. Additionally, levels of Bacteroides, Geobacillus, Meiothermus, and Anoxybacillus genera were significantly higher in CCA patients’ biliary microbiota, without an associated disease, in comparison with controls

A specific CCA-related dysbiosis was identified as compared to controls independently from associated diseases. This suggests that a microorganism community may be involved in CCA pathogenesis