S1314 The Effect of Probiotic Mixture on the Symptoms and Fecal Microbiota in Diarrhea-Dominant Irritable Bowel Syndrome: Randomized, Double-Blind, Placebo-Controlled Trial

Abstract

Background & Aims: Some reports suggest that probiotics are helpful for treatment of Irritable bowel syndrome (IBS). The aim of this study was to evaluate the effects of probiotic mixture compared with placebo on the symptoms and the compositions of fecal microbiota in patients with diarrhea-dominant IBS (D-IBS). Methods: Forty-seven patients with D-IBS consented by ROME III were randomized in a parallel group, double-blind design to placebo or seven probiotics mixture 7x1011 CFU (Streptococcus thermophous, Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium lactis, Bifidobacterium longum, Bifidobacterium breve) daily for 8 weeks after 1-week run-in period. The primary outcome was the adequate relief (AR) for overall IBS symptoms; secondary outcomes included the individual IBS symptoms, and the IBS quality of life (IBS-QOL). The AR was weekly checked by questionnaire for 10 weeks (8 weeks of treatment phase, 2 weeks of post-treatment phase). The IBS symptom diary based on visual analogue scale (VAS for abdominal pain, abdominal discomfort, diarrhea, urgency, mucus in stool, bloating, passage of gas) and stool parameters (hardness and frequency) were recorded on a daily basis and assessed each week for 11 weeks. IBS-QOL assessment and stool sampling for evaluating the composition of fecal microbiota by denaturing gradient gel electrophoresis (DGGE) were performed at the beginning and at the end of the treatment phase. Results: For all weeks, the proportions of AR was higher in probiotics group than placebo (p<0.05). The proportion of the patients who reported “yes” to adequate relief on half of the weeks (5 weeks) in the treatment trial was significantly higher in probiotics group than placebo (50% vs. 13%, p= 0.01). However, the improvements of the individual symptom scores and stool parameters were not superior in probiotics group. In IBS-QOL, the changing rates of overall scores for probiotics group tended to be higher than those for placebo (21.3±21.6% vs. 9.0±21.5%, p=0.073). The improvements of all 8 domains of IBS-QOL were consistently superior in probiotics group. In the comparison for DGGE profiles of fecal bacteria, there was no difference in the similarities of their bacterial compositions between the two groups. The concordance rates of bacterial compositions from the two time-points were 66.2±13.4% in probiotics and 69.1±11.8% in placebo group (p=0.519). Conclusion: The probiotic mixture is effective in providing adequate relief of overall IBS symptoms, and has a tendency to improve of IBS-QOL in D-IBS. But, the effect of probiotics is not related with the compositional changes of fecal microbiota.