Effect of Saccharomyces boulardii CNCM I-745 as complementary treatment of Helicobacter pylori infection on gut microbiome

Conventional therapy for H. pylori infection includes the combination of antibiotics and a proton-pump inhibitor. Addition of probiotics as adjuvants for H. pylori antibiotic treatment can increase eradication rate and decrease treatment side effects. Although many studies show the benefits of S. boulardii CNCM I-745 in the treatment of H. pylori infection, the mechanism by which those benefits are achieved is unknown. Here, we report clinical characteristics and fecal microbiota changes comparing conventional anti-H. pylori therapy versus conventional therapy supplemented with S. boulardii CNCM I-745. A total of 74 patients were included in the current study; patients positive for H. pylori (n = 63) were randomly assigned to 2 groups: 34 patients received conventional therapy and 29 antibiotic therapy plus 750 mg of S. boulardii CNCM I-745 daily, for 2 weeks. Eleven patients negative for H. pylori infection were also studied. Patients provided 3 fecal samples: before initiating the antibiotic treatment, upon its completion, and 1 month after treatment. Patients were contacted every 72 h to inquire about side effects and compliance. DNA was extracted, and 16S rRNA was amplified and sequenced on Illumina MiSeq. Bioinformatic analysis was performed using QIIME2. Patients who received the probiotic had a significantly lower frequency of associated gastrointestinal symptoms (P = 0.028); higher number of bacterial diversity evenness (P = 0.0156); higher abundance of Enterobacteria; and lower abundance of Bacteroides and Clostridia upon treatment completion. Addition of S. boulardii CNCM I-745 induced a lower frequency of gastrointestinal symptoms that could be related to changes in gut microbiota.