Longitudinal Shifts in Gut Microbiota After Cholecystectomy: A Point of No Return in Losing Lactobacillus Spp.

Cholecystectomy alters bile acid dynamics and may influence gut microbiota composition. However, longitudinal data with preoperative baseline assessment remain limited, and existing evidence is largely based on cross-sectional studies with inconsistent findings. In this prospective cohort study, we aimed to characterize longitudinal changes in gut microbiota following cholecystectomy and explore their clinical relevance. Patients planning to undergo laparoscopic cholecystectomy were recruited and followed for 12 months. Stool samples were collected at baseline and at 1, 3, 6, and 12 months postoperatively. Microbiota composition was analyzed using 16S rRNA gene sequencing. Microbial diversity and differential abundance were evaluated using complementary statistical approaches, including longitudinal analyses accounting for repeated measurements. Clinical outcomes, including stool form and defecation frequency, were recorded. Twenty participants completed follow-up. Overall microbial diversity and community structure showed only modest changes over time. In contrast, differential abundance analyses consistently demonstrated an early postoperative reduction in the genus Lactobacillus, which remained relatively stable thereafter. Functional prediction suggested modest alterations in metabolic pathways without major disruption of global microbial function. No participants developed clinically significant post-cholecystectomy diarrhea. In conclusion, gut microbiota after cholecystectomy exhibited relatively modest overall changes but selective taxonomic alterations, particularly a persistent reduction in Lactobacillus. These findings suggest targeted microbial restructuring rather than global dysbiosis and may help explain the low incidence of post-cholecystectomy diarrhea.