Alterations in the Saliva Microbiome in Patients with Gastritis and Small Bowel Inflammation

The oral microbiome is an important part of the human microbiome. Accumulating data have shown that oral microbiome alterations are closely related to multiple human diseases. However, salivary microbiota distributions remain unclear in patients with gastritis and small bowel inflammation. Magnetically guided capsule endoscopy (MGCE) is a noninvasive diagnostic tools for patients with gastritis and small bowel inflammation. Herein, we analysed the changes in saliva microbiota in the normal, small intestinal inflammation and chronic gastritis groups through 16S rRNA gene amplicon sequencing. At the phylum level, the relative proportion of Proteobacteria and Bacteroidetes was lower in patients with gastritis than in control patients. At the genus level, the relative abundance of Neisseria in the gastritis group also decreased. Compared with normal samples, the gastric samples had upregulated Porphyromonas levels. At the phylum level, the relative Proteobacteria proportion was lower in patients with small bowel inflammation than in healthy patients, whereas the relative abundance of Bacteroides increased. Our findings clarify the saliva microbiota components and the importance of specific bacteria in gastritis and small bowel inflammation and can be used to develop preventive and noninvasive diagnostic strategies.