Evaluation of the Gastric Microbiota Based on Body Mass Index Using 16S rRNA Gene Sequencing

Helicobacter pylori has been suggested to be associated with various gastrointestinal diseases as well as obesity and metabolic disorder. However, other gastric microbiota remain understudied in relation to obesity. In a previous study on mice, high-fat diets induced dysbiosis not only in the intestinal but also in the gastric microbiota. Therefore, this study aimed to investigate the gastric microbiota composition according to body mass index (BMI) categories and their potential associations with metabolic indices in humans. The relationship between gastric microbiota, except H. pylori, and obesity was investigated by analyzing gastric mucosal samples using 16S rRNA gene sequencing and functional profiling. We believe that our study makes a significant contribution to the literature, as it demonstrates that obesity may be associated not only with the intestinal microbiota but also with the gastric microbiota. Muribaculum gordoncarteri, Turicibacter bilis, and Duncaniella dubosii abundance was notably reduced in the overweight/obese group. Metagenomic prediction highlighted associations of certain metabolic pathways, including those related to fatty acid, amino acid, vitamin, and carbohydrate metabolism, with BMI categories. Significant differences in gastric microbiota between overweight/obese and normal groups indicate a potential association between gastric microbiota and obesity, and a potential role of gastric microbial communities in the pathogenesis of obesity.