Gut microbial profile in biliary atresia: a case-control study

Background and aim: Biliary atresia (BA) is a progressive fibro-inflammatory cholangiopathy with an unclear etiology. Various liver disorders are associated with an altered microbiome. However, gut microbiome in BA remains unknown. Here, we performed a case-control study to investigate the gut microbiota in BA.

Methods: A cross-sectional analysis was first conducted for 34 BA patients and 34 healthy controls. Then we investigated the shift in gut microbiota 2 weeks after the Kasai procedure in 16 BA patients. Gut microbiome was initially analyzed using 16S ribosome RNA gene sequencing and further validated by metagenomic sequencing. Fecal bile acids were determined using ultra-high performance liquid chromatography.

Results: Compared with healthy controls, BA showed lower diversity and significant structural segregation in the microbiome. At phylum level, Proteobacteria numbers increased, whereas those of Bacteroidetes decreased in BA. At genus level, several potential pathogens such as Streptococcus and Klebsiella thrived in BA, while numbers for Bifidobacterium and several butyrate-producing bacteria declined. The microbiome was also disturbed after the Kasai procedure. Operational taxonomic units responding to BA showed significant correlation with liver function. Furthermore, the abundance ratio of Streptococcus/Bacteroides showed great promise in distinguishing BA from healthy controls. Intestinal bile acids were dramatically decreased in BA, and Clostridium XIVa positively correlated with the ratio of primary/secondary bile acids.

Conclusions: Gut microbial dysbiosis, may be caused by decreased bile acids, was associated with liver function and had a good diagnostic potential for BA. Therefore, further exploration of gut microbiota may provide important insights into their potential diagnostic and therapeutic benefits.