Bifidobacterium adolescentis PRL2019 in Pediatric Irritable Bowel Syndrome: A Multicentric, Randomized, Double-Blind, Placebo-Controlled Trial

The gut microbiota plays a pivotal role in gastrointestinal inflammation and immune response since changes in microbiota may result in abnormal neurotransmitter expression, inducing changes in gastrointestinal sensory–motor function and leading to symptom onset in irritable bowel syndrome (IBS) patients. The Bifidobacterium adolescentis species has a documented immunomodulatory effect through its ability to produce γ-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the mammalian central nervous system, which is reduced in IBS patients. This is a multicentric, randomized, double-blind, placebo-controlled, parallel-arm trial aimed at evaluating the effectiveness of Bifidobacterium adolescentis PRL2019 in children with IBS. IBS children diagnosed according to Rome IV criteria were enrolled and randomized into two groups to receive one stick containing 20 × 109 colony-forming unit of Bifidobacterium adolescentis PRL2019 (Gabapral, Pontenure, Italy) or an equivalent placebo once a day, in a 1:1 ratio, for 12 weeks. Clinical evaluation of symptoms was performed every four weeks using validated scores. Bowel habit characteristics were assessed using the Bristol Stool Chart (BSC). Seventy-two subjects (mean age 12.2 ± 1.8 years, 30 males) were enrolled and randomized into two groups, each of thirty-six patients. No significant differences were observed between the two groups regarding demographic characteristics, distribution of IBS subtypes, or baseline measures of IBS severity and BSC. The proportion of patients achieving complete remission was significantly higher in the BA Group (19/36; 52.8%) than in the Placebo Group (7/36; 19.4%, p = 0.003, odds ratio [OR] 0.216, 95% confidence interval [CI] 0.075–0.619). Both groups obtained a reduction in Total IBS Symptom Severity Scale (IBS SSS), Pain Intensity Score (PIS), Pain Frequency Score (PFS), and Life Interference Score (LIS) from T0 to T12. However, upon intergroup comparison, only in the BA group did the IBS-SSS (p = 0.001), PIS (p = 0.001), LIS (p = 0.015), and PFS (p = 0.005) significantly improve between T0 and T12. BSC showed a greater representation of normal stools (type 3–4) at the end of treatment in the BA group compared with baseline (25% vs. 58.3%, p = 0.004), especially in patients who presented an IBS–constipation subtype at T0 (44.5% vs. 19.4%, p = 0.02). In our study, Bifidobacterium adolescentis PRL2019 reduces the severity and frequency of symptoms in children with IBS, positively affecting bowel habits in children with the IBS–constipation subtype.