Effect of Probiotics on the Gut Microbiota After Colonoscopy: A Multicenter, Randomized, Placebo-Controlled Clinical Study

Abstract

Background and aim: Alterations in gut microbiota after colonoscopy have been observed. Moreover, there is limited consensus regarding the impact of the procedure on gut microbiota. We aim to evaluate whether the probiotic can treat gut microbiota and abdominal symptoms disturbance after colonoscopy.

Methods: A total of 301 participants were randomized into probiotic and placebo groups. The probiotic group received live combined Bacillus Subtilis and Enterococcus Faecium-coated capsules (0.5 g thrice daily for 28 days) postcolonoscopy. The placebo group was given placebo in an identical manner. Fecal samples were collected from participants and symptoms were reported. The intestinal microbiota composition was assessed using 16S rRNA sequencing.

Results: Notable differences in α (p = 0.011) and β (p < 0.001) diversity were observed after colonoscopy. Bowel cleansing resulted in the proliferation of Pseudomonas and Klebsiella in the placebo group. However, the probiotic group exhibited a marked enrichment in beneficial probiotics such as Lactobacillales (p = 0.002). Gastrointestinal symptom rating scale (GSRS) showed significant improvements in the probiotic group within the initial week (p = 0.005). Patients in the probiotic group who exhibited symptoms experienced fewer days of abdominal discomfort postcolonoscopy (p = 0.034). Additionally, they exhibited enhanced glucose metabolism (p = 0.040) and a notable increase in Lactobacillales (p = 0.009). In the probiotic group, α and β diversities differed significantly in patients without GSRS improvements, and the concentration of Bacteroides was significantly elevated (p = 0.004).

Conclusion: Gut microbiota was altered after colonoscopy, especially the proliferation of potentially pathogenic bacteria. Administering probiotics postcolonoscopy leads to beneficial alterations in gut microbiota and associated metabolic pathways, while abdominal discomfort symptoms were improved early.