The Efficacy of Single-strain Probiotics in Patients With Irritable Bowel Syndrome
Condition: Irritable Bowel Syndrome
MeSH terms: Irritable Bowel Syndrome; Syndrome
Study type: Interventional

Summary: 
      Irritable bowel syndrome (IBS) is one of the most common, yet still not fully understood,
      gastrointestinal disorders in adults. One suspected etiology involves intestinal dysbiosis,
      i.e. both quantitative and qualitative alterations in intestinal microbiota composition,
      which affects the gut-brain axis. Probiotics are live microorganisms, which-administered at
      the right dose-are beneficial for human health; their mechanism of action involves modifying
      the gut microbiota. Clinical study reports document that probiotic administration is
      beneficial for patients with IBS. The ultimate clinical effects depend primarily on probiotic
      strain selection. Our research team evaluated a multi-strain probiotic formulation and a
      multi-strain synbiotic (a combination of probiotic strains with short-chain prebiotic
      fructooligosaccharides) formulation as part of two randomized placebo-controlled clinical
      trials in patients with IBS with predominant diarrhea. The results indicated a beneficial
      effect of these formulations on the clinical course of IBS assessed with the international
      IBS symptom severity scale (IBS-SSS), with each of the study formulations exhibiting efficacy
      in different fields. The formulation composed of a mixture of Bifidobacterium and
      Lactobacillus strains reduced the levels of pain and improved the quality of life, whereas
      the synbiotic formulation effectively improved bloating and had a beneficial effect on the
      general condition of the intestines. A systematic review and meta-analysis published in 2020
      showed that high doses of single-strain formulations, particularly those containing
      Bifidobacterium or Lactobacillus strains, may be more effective in IBS patients. Other
      reports demonstrated a high efficacy of the new-generation probiotic Bacillus coagulans in
      IBS. Therefore, the main objective of this research project is to assess the efficacy of
      single-strain probiotics containing Bifidobacterium lactis or Bacillus coagulans in patients
      with IBS.
    

Detailed description: 
      This is a randomized double-blind placebo-controlled trial included 120 adult patients, who
      had been diagnosed with IBS according to the Rome IV diagnostic criteria. The patients will
      receive orally a probiotic formulation containing Bifidobacterium lactis or Bacillus
      coagulans or placebo over a period of 12 weeks. Once the period of supplementation is
      completed, the patients will be followed-up for the subsequent 4 weeks. The patients included
      in the study will receive diaries, which they will complete daily. The patient's dairy will
      include information about the number of stools, stool consistency (assessed based on the
      Bristol Stool Form Scale) and IBS symptoms (abdominal pain, bloating, bowel urgency, and
      feeling of incomplete evacuation) rated in a 5-grade scale. The diary will also include
      information on any adverse events and the use of any new medications during the study. Once a
      week, the patients will be contacted by phone by interviewers who will collect the
      information recorded in the patient's diary.

      During the first visit, the patients included in the study will be informed of the study
      procedure and educated on the phone exchanges with the interviewers. One week prior to study
      intervention, the patients will be asked to record their symptoms in their patient diaries
      every day. Subsequently, the patients will visit their study doctor every four weeks (from
      the beginning of the study intervention) in order to receive the next dose of the study
      formulation/placebo. During each study visit, the patients will be evaluated with the use of
      IBS-SSS and IBS Global Improvement Scale (IBS-GIS). The patients included in the study will
      undergo a hydrogen breath test for small intestinal bacterial overgrowth (SIBO) both prior to
      receiving the study formulation/placebo and 12 weeks later, after intervention is completed.

      The study will last a total of 16 weeks from the moment the intervention is initiated (12
      weeks of interventions and 4 weeks of follow-up).
    

Intervention name(s): Probiotic Bifidobacterium lactis; Probiotic Bacillus coagulans; Placebo
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): The probiotic will be administered orally over a period of 12 weeks.; The probiotic will be administered orally over a period of 12 weeks.; Maltodextrin as a placebo will be administered orally over a period of 12 weeks. The taste and appearance of the placebo will be similar to those of the probiotic formulation.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Probiotics