Identifying Gut Microbiota associated with Gastrointestinal Symptoms upon Roux-en-Y Gastric Bypass

Effects of Probiotic Use on Gastrointestinal Symptoms in the Late Postoperative Period of Bariatric Surgery: A Cross-Over, Randomized, Triple-Blind, Placebo-Controlled Study

INTRODUCTION

Despite the benefits associated with weight reduction, the anatomical and functional changes of bariatric surgery may favor the development of undesirable side effects such as the appearance of gastrointestinal symptoms (GIS). The aim of this study was to evaluate the effects of using probiotics in individuals with GIS 1 year after being submitted to Roux-en-Y Gastric Bypass (RYGB).

MATERIALS AND METHODS

This is an experimental, prospective, randomized, cross-over, triple-blind, placebo-controlled study, carried out with patients 1 year after being submitted to RYGB and who reported at least one moderate GIS. Subjects were randomized into two groups and completed the two research periods: in one they received placebo capsules, in the other 50 billion CFU of probiotics (Lactobacillus acidophilus, Bifidobacterium lactis, Lactobacillus rhamnosus, Bifidobacterium longum, Lactobacillus plantarum, Bifidobacterium bifidum and Lactobacillus gasseri), both for 8 weeks, with 8 weeks of wash-out period in between, and were evaluated for the presence of Small Intestine Bacterial Overgrowth (SIBO) and GIS, through the Hydrogen breath test and Gastric Symptom Rating Scale (GSRS) questionnaire.

RESULTS

Of a total of 56 participants, 47 individuals completed the study. No significant effects were observed in neither the gastrointestinal symptoms or in the prevalence of SIBO with the use of probiotics.

CONCLUSION

Supplementation of the probiotics chosen for this study does not seem to alleviate GIS or influence the improvement of SIBO in symptomatic patients after 1 year of RYGB.

Novel primers to identify a wider diversity of butyrate-producing bacteria

Butyrate-producing bacteria are a functionally important part of the intestinal tract flora, and the resulting butyric acid is essential for maintaining host intestinal health, regulating the immune system, and influencing energy metabolism. However, butyrate-producing bacteria have not been defined as a coherent phylogenetic group. They are primarily identified using primers for key genes in the butyrate-producing pathway, and their use has been limited to the Bacillota and Bacteroidetes phyla. To overcome this limitation, we developed functional gene primers able to identify butyrate-producing bacteria through the butyrate kinase gene, which encodes the enzyme involved in the final step of the butyrate-producing pathway. Genomes extracted from human and rat feces were used to amplify the target genes through PCR. The obtained sequences were analyzed using BLASTX to construct a developmental tree using the MEGA software. The newly designed butyrate kinase gene primers allowed to recognize a wider diversity of butyrate-producing bacteria than that recognized using currently available primers. Specifically, butyrate-producing bacteria from the Synergistota and Spirochaetota phyla were identified for the first time using these primers. Thus, the developed primers provide a more accurate method for researchers and doctors to identify potential butyrate-producing bacteria and deepen our understanding of butyrate-producing bacterial species.