The response of biliary atresia (BA) after surgical Kasai portoenterostomy (KP) is inconsistent and reliant on bile flow; 50% of newborns require a liver transplant by 24 months. Researchers predicted that the microbiota might detect and correlate with BA outcomes. Stool samples were obtained from cholestasis babies, 8 of whom had a BA and were monitored longitudinally. All samples were subjected to 16S sequencing. BA pre-KP samples were subjected to Whole Genome Sequencing (WGS). Babies with BA, other types of cholestasis, and BA babies with very excellent bile flow (VGBF) and without (nVGBF) were compared. Four of the eight babies with BA had VGBF. The degree of cholestasis was inversely related to microbial richness. At 1 month post-KP, there was an increase in Bifidobacterium abundance linked with VGBF and a reduction in cholestasis. Pre-KP, community structure varied between babies with BA and those with other types of cholestasis. Interestingly, during the pre-KP time period, babies who later attained VGBF had higher variety and a distinct community structure. The significance of Bifidobacterium in pre-KP was confirmed by WGS.

Infants with BA have a different microbiome than those with other types of cholestasis. It also differentiates between babies with BA who have adequate bile flow and those who have poor bile flow, and therefore outcomes post-KP. These distinctions can be noticed even before KP. These findings show that bile impacts the development of the newborn microbiome and that the pre-and post-KP microbiota may have an impact on bile flow after KP. Larger investigations are required to corroborate these conclusions.