Background and Objectives: The aim of this study was to compare the differences in compositions of oral and fecal bacterial microbiota between patients with morbid obesity and normal-weight controls. Material and Methods: This was a prospective cohort study. The study included group 1 (patients with BMI ≥ 40 kg/m2) and group 2 (patients with BMI from 18.5 to 24.9 kg/m2). Our endpoint was the analysis of the differences in compositions of oral and fecal microbiota between the groups. Oral swabs and fecal samples were collected from the patients. The analysis of microbiota was conducted using next-generation sequencing. Results: Overall, the study included 96 patients; 52 (54.2%) were included in group 1, 44 (39.8%)-in group 2. In group 1, oral microbiota included significantly more bacteria from genera Veillonella, Oribacterium and Soonwooa, whereas, in group 2, Streptobacillus, Parvimonas and Rothia were more common. Fecal microbiota in group 1 included more Bacteroides, Odoribacter and Blautia and group 2 was more abundant in Ruminococcus, Christensenella and Faecalibacterium. Conclusions: Both oral and fecal gastrointestinal microbiota differs significantly among patients with severe obesity and lean individuals.
Keywords: BMI; body mass index; microbiome; microbiota; obesity.