Efficacy of Probiotic Escherichia coli Nissle 1917 in Patients with Irritable Bowel Syndrome: a Double Blind Placebo-controlled Randomized Trial.

AIM: to evaluate potential improvement effect for probiotic E. coliNissle 1917 in the management of refractory IBS in an Iranian population.

METHODS: a double blind placebo controlled approach has been used in the current clinical trial. 139 confirmed IBS patients were included into the study, and were given probiotic E.coli Nissle 1917 for 6 weeks. 11 items Birmingham IBS Symptom Questionnairehas been used for evaluation of changes in the symptoms every 2 weeks.

RESULTS: sixty eight subjects (49%) were males. Mean±SD age of the participants was 38±13.3 years. 49(35.3%) of the patients were diarrhea-predominant. The total scores showed no significant difference between the intervention vs. control group(-6.7±6.8 vs. -6.7±6.5, respectively; p=0.95); neither did any of the questionnaire items any significant alterations in the two groups. After stratification of patients based on their IBS type, diarrhea-predominant patients showed a positive response to the probiotic improving their sleep (p=0.05 and 0.03 at weeks 2 and 6, respectively). Patients with constipation-predominant IBS showed no response to the probiotic; while patients with diarrhea-constipation mixed IBS showed unfavorable response to the probiotic in the need for strain to pass a motion compared to the placebo (p=0.03 and 0.02 at weeks 4 and 6, respectively).

CONCLUSION: probiotic therapy with E.coli Nissle 1917 was not able to induce significant improvement in the symptoms of patients with non-categorized IBS. Nevertheless, when IBS patients were recategorized to subgroups according to their main symptoms, evaluation of the efficacy of the probiotic on some individual items in the symptom list reached the significance level. Prospective clinical trials are recommended to confirm our findings.