Alteration of the fecal microbiome in patients with cholecystectomy: potential relationship with postcholecystectomy diarrhea – before and after study

BACKGROUND: Bile acid (BA) is a crucial determinant of the gut microbiome, and cholecystectomy can alter the physiology of BA. Physiological changes in BA resulting from cholecystectomy can also influence the gut microbiome. We aimed to identify the specific taxa associated with perioperative symptoms, including postcholecystectomy diarrhea (PCD), and to evaluate the effect of cholecystectomy on the microbiome by investigating the fecal microbiome of patients with gallstones. METHODS: We analyzed the fecal samples of 39 patients with gallstones (GS group) and 26 healthy controls (HC group) to evaluate their gut microbiome. We also collected fecal samples from GS group 3 months postcholecystectomy. Symptoms of patients were evaluated before and after cholecystectomy. Further, 16S ribosomal RNA amplification and sequencing were performed to determine the metagenomic profile of fecal samples. RESULTS: The microbiome composition of GS differed from that of HC; however, the alpha diversity was not different. No significant microbiome alterations were observed before and after cholecystectomy. Moreover, GS group showed a significantly lower Firmicutes to Bacteroidetes ratio before and after cholecystectomy than the HC group (6.2, P<0.05). The inter-microbiome relationship was lower in GS than in HC and tended to recover 3 months after surgery. Furthermore, ~28.1% (n=9) of patients developed PCD after surgery. The most prominent species among PCD (+) patients was Phocaeicola vulgatus. Compared with the preoperative state, Sutterellaceae, Phocaeicola, and Bacteroidals were the most dominant taxa among PCD (+) patients. CONCLUSION: GS group showed a different microbiome from that of HC; however, their microbiomes were not different 3 months after cholecystectomy. Our data revealed taxa-associated PCD, highlighting the possibility of symptom relief by restoring the gut microbiome.