Relationship between bariatric surgery outcomes and the preoperative gastrointestinal microbiota: a cohort study

BackgroundThe composition of the gastrointestinal microbiota is associated with obesity. We hypothesized that the gut microbiota influences the outcomes of bariatric surgery.ObjectivesWe aimed to analyze using oral swabs and stool samples the microbiota of patients with morbid obesity who were undergoing laparoscopic sleeve gastrectomy (SG).SettingA university hospital in Poland.MethodsThis prospective cohort study was conducted between November 2018 and June 2019. Participants underwent SG or no surgery (controls). Results were then analyzed as a group 1 (surgical participants who achieved a percentage of excess weight loss [%EWL] >50%), group 2 (surgical participants who achieved a %EWL <50%), and group 3 (nonsurgical controls). %EWL was measured 6 months following surgery. Before surgery, oral swabs were obtained and stool samples were provided. The endpoint was the composition of the gut microbiota.ResultsGroup 1 comprised 19 participants, group 2 comprised 11 participants, and group 3 comprised 16 participants. No participants were lost to follow-up during the study. Participants in group 1 had an oral microbiota that was enriched in the phyla Proteobacteria, and Bacteroidetes. Their intestinal microbiota was enriched in the Proteobacteria. In contrast, the oral microbiota of group 2 was enriched in the Actinobacteria and the intestinal microbiota was enriched in the phyla Bacteroidetes and Firmicutes.ConclusionsThe compositions of the microbiota of the oral cavity and large intestine are related to the weight loss achieved following SG.     

Changes in the Composition of Oral and Intestinal Microbiota After Sleeve Gastrectomy and Roux-En-Y Gastric Bypass and Their Impact on Outcomes of Bariatric Surgery

Background

We aimed to assess the changes in composition of bacterial microbiota at two levels of the digestive tract: oral cavity and large intestine in patients 6 months after bariatric surgery.

Methods

This was a prospective cohort study including patients undergoing bariatric surgery. Before surgery and 6 months after the procedure, oral swabs were obtained and stool samples were provided. Our endpoint was the analysis of the differences in compositions of oral and fecal microbiota prior and after the surgical treatment of obesity.

Results

Bacteria from phylum Bacteroidetes seemed to increase in abundance in both the oral cavity and the large intestine 6 months after surgery among patients undergoing bariatric surgery. The subgroup analysis we conducted based on the volume of weight-loss revealed that patients achieving at least 50% of excess weight loss present similar results to the entire study group. Patients with less favorable outcomes presented an increase in the population of bacteria from phylum Fusobacteria and a decrease of phylum Firmicutes in oral cavity.

Conclusion

Intestinal microbiota among these patients underwent similar changes in composition to the rest of the study group. Bariatric surgery introduces a significant change in composition of oral and intestinal microbiota.

Graphical abstract