Impact of Oral Administration of Lactobacillus reuteri LMG-P 27481 on Human Gut Microbiota Diversity and Function: A Pilot Study

Background: Many literature studies have reported the beneficial effects of probiotics on human health, but few articles have evaluated their “real effects” on the modulation of microbiota after their use. Lactobacillus reuteri (L. reuteri) is one of the most studied probiotics with the best effects on gut microbiota. Aims: The primary aim of our study was the evaluation of the intestinal colonization by L. reuteri-LMG P 27481 and its effects on the modification of the gut bacterial flora. The secondary aim was the evaluation of side effects through the validated Gastrointestinal Symptom Rating Scale (GSRS). Patients and Methods: This is an interventional, open-label study conducted on 20 healthy adults (10 men and 10 women M/F; mean age 34 ±15 years) who received a probiotic Reuterin^® LMG (L. reuteri LMG P 27481) for 28 consecutive days in drops at a concentration of 1 × 10⁹ (five drops per day). Microbiota analysis was performed at enrollment (T0), at the end of probiotic supplementation (T1) and after a 14-day follow-up period (T2). Results: In our study we observed interesting quantitative and functional variations as regards the Firmicutes/Bacterioidetes ratio, intestinal permeability, and the production of short-chain fatty acids (SCFA). This probiotic was safe and was able to improve patients’ symptoms. Conclusions: The intake of L. reuteri LMG-P 27481 in healthy subjects showed transitory variations in some functional and metabolic gut functions, especially an improvement in the barrier effect and intestinal permeability,y and an increase in SCFA. Future studies should include target populations to have a greater range for modulation of the gut microbiota.