Effect of Combined Live Probiotics Alleviating the Gastrointestinal Symptoms of Functional Bowel Disorders

Abstract

Objective: Changes of the gut microbiota are related to the pathogenesis of functional bowel disorders (FBDs), and probiotic supplementation may be an effective treatment option. Therefore, we aimed to investigate the effect of combined live probiotics on the gastrointestinal symptoms of FBDs via altering the gut microbiota.

Methods: Patients with the gastrointestinal symptoms of FBDs attending the Outpatient Department, from July to November 2019, were recruited. After the bowel preparation with polyethylene glycol electrolyte powder and colonoscopy, patients with normal result of colonoscopy were randomly divided into the probiotics group and control group. Patients in the probiotics group were prescribed with combined live Bacillus subtilis and Enterococcus faecium enteric-coated capsules for 4 weeks. Small intestinal bacteria overgrowth (SIBO) was measured by lactulose hydrogen breath test, and the microbial DNA was extracted from the fecal samples and the bacteria were classified by 16S rDNA gene amplicon sequencing.

Results: Twenty-five patients of each group were recruited, and there was no significant difference between the probiotics and control groups on baseline gastrointestinal symptom rating scale (GSRS), positive rate of SIBO, and relative abundances of the gut microbiota at the phylum level. After 4 weeks of treatment, the values of the probiotics and control groups were as follows: GSRS 1.4 ± 1.4 and 3.6 ± 1.6 and positive rate of SIBO 28.0% and 56.0%, respectively. The median relative abundances of the gut microbiota were 1.01% and 5.03% Actinobacteria and 43.80% and 35.17% Bacteroidetes at the phylum level; 0.76% and 3.29% Bifidobacterium, 0.13% and 0.89% Cillinsella, 0.03% and 0.01% Enterococcus, 0.18% and 0.36% Lachnospiraceae, 0.10% and 0.16% Ruminococcus torques group, 1.31% and 2.44% Blautia, and 0.83% and 2.02% Fusicatenibacter at the genus level (P < 0.05), respectively.

Conclusion: Combined live probiotic supplementation after the bowel preparation can alter the gut microbiota, decontaminate SIBO, and alleviate the gastrointestinal symptoms of FBDs. This trial is registered with ChiCTR1900026472.

Figure 1

Flow chart of enrollment.

Figure 2

Changes of gastrointestinal symptom rating scale (GSRS). GSRS scores at the time of 2 weeks and 4 weeks after colonoscopy and treatment were significantly lower than those at the baseline of the probiotics and control groups. But GSRS score at the time of 4 weeks after colonoscopy and treatment was significantly higher than that at the time of 2 weeks after colonoscopy and treatment in the control group.

Figure 3

Differences in the composition of the gut microbiota between the baseline and 4 weeks after colonoscopy and treatment groups. Gut bacteria with linear discriminant analysis score > 2.0 between the baseline and 4 weeks after colonoscopy and treatment in the probiotics group (a) and control group (b) at the levels of class, order, family, and genus.

Figure 4

Box plot of the Shannon index and Simpson index in the probiotics group (a) and control group (b). Shannon index and Simpson index, indicating an α-diversity, were significantly lower in the 4 weeks after colonoscopy and treatment than those in the baseline of probiotics group. There was no significant difference in the control group.

Figure 5

Differences in microbiota composition (β-diversity) in the probiotics group (a) and control group (b). Principal coordinate analysis (PCoA) and nonmetric multidimensional scaling (NMDS) analysis between the baseline and 4 weeks after colonoscopy and treatment. The β-diversity 4 weeks after colonoscopy and treatment of the probiotics group were more divergent than those in the baseline. However, the β-diversity 4 weeks after colonoscopy and treatment of the control group were less divergent than those in the baseline. PC1: principal coordinate 1; PC2: principal coordinate 2.