The oral-gut axis: Salivary and fecal microbiome dysbiosis in patients with inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a group of chronic inflammatory disorders that fall into two main categories: Crohn's disease (CD) and ulcerative colitis (UC). The gastrointestinal tract extends from the mouth to the anus and harbors diverse bacterial communities. Several sequencing-based studies have identified an intestinal enrichment of oral-associated bacteria and demonstrated their ability to induce intestinal inflammation in mice, suggesting that intestinal pathobionts originate from the oral cavity, particularly members of the genus Streptococcus. This study aimed to investigate the composition of the salivary and fecal microbiome of IBD patients (n = 14) compared to healthy controls (n = 12) and to determine the abundance of common bacterial taxa in both niches. Metagenomic DNA was extracted from saliva and fecal samples, and the 16S rRNA gene was targeted for sequencing. Our results revealed that the overall microbial composition of saliva was significantly altered in the IBD patients compared to the control subjects (p = 0.038). At the genus level, Veillonella and Prevotella were highly abundant in IBD (median: 25.4% and 22.2%, respectively) compared to the control group (17.9% and 13.4%, respectively). In contrast, Neisseria, Streptococcus, Haemophilus, and Fusobacterium were associated with a healthy gut state. Regarding the fecal microbiome, the IBD group had a significantly higher abundance of Clostridium sensu stricto 1 and Escherichia-Shigella (both comprising pathogenic bacteria) compared with the control group. Members of both bacterial groups have previously been shown to positively correlate with intestinal inflammation and high expression of pro-inflammatory cytokines that disrupt intestinal barrier integrity. In addition, we demonstrate that the increased abundance of Clostridium sensu stricto 1 and Escherichia-Shigella has also been associated with significant upregulation of certain metabolic pathways in the feces of the IBD group, including bacterial invasion of epithelial cells. Streptococcus was the only common genus detected in both the salivary and fecal microbiome and represented the oral-gut axis in our study. Using culture-based methods, we isolated 57 and 91 Streptococcus strains from saliva as well as 40 and 31 strains from fecal samples of the controls and IBD patients, respectively. The phylogenetic tree of streptococci based on sodA sequences revealed several patient-specific clusters comprising salivary and fecal streptococcal isolates from the same patient and belonging to the same species, suggesting that the oral cavity is an endogenous reservoir for intestinal strains.

Abdelbary MMH ，Hatting M ，Bott A ，Dahlhausen A ，Keller D ，Trautwein C ，Conrads G ... -  《Frontiers in Cellular and Infection Microbiology》

Microbiome and its relevance to indigenous inflammatory bowel diseases in China.

Inflammatory Bowel Disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract with an unknown etiology. Although dysbiosis is implicated in its pathogenesis, deep sequencing and oral microbiota study in Chinese IBD patients is absent. To explore the role of oral / intestinal microbiota in patients with IBD and the potential associations therein. Clinical data, fecal and saliva samples were harvested from 80 patients with IBD (Crohn's disease, CD, n = 69; Ulcerative colitis, UC, n = 11) and 24 normal controls. Microbiomics (16S rRNA sequencing and 16S rRNA full-length sequencing) were used to detect and analyze the difference between IBD patients and normal control. Compared with normal controls, a higher abundance of the intestinal Shigella spp. (Shigella flexneri and Shigella sonnei, which were positively relate to the severity of IBD), lower abundance of intestinal probiotics (Prevotella, Faecalibacterium and Roseburia), and higher abundance of oral Neisseria were present in IBD patients with microbiome. The higher inflammation-related markers, impaired hepatic and renal function, and dyslipidaemia were present in patients with IBD. A higher intake of red meat and increased abundance of Clostridium in the gut were found in CD patients, while the elevated abundance of Ruminococcus in the gut was showed in UC ones. The bacterial composition of saliva and fecal samples was completely different, yet there was some correlation in the distribution of dominant probiotics. Enteric dysbacteriosis and the infections of pathogenic bacteria (Shigella) may associate with the occurrence or development of IBD.

Han A ，Yang M ，Chen B ，Cao G ，Xu J ，Meng T ，Liu Y ，Wang Z ，Zhou Y ，Xu N ，Han W ，Sun H ，Mei Q ，Zhu L ，Xiong M ... -  《-》

Dysbiosis of salivary microbiota in inflammatory bowel disease and its association with oral immunological biomarkers.

Said HS ，Suda W ，Nakagome S ，Chinen H ，Oshima K ，Kim S ，Kimura R ，Iraha A ，Ishida H ，Fujita J ，Mano S ，Morita H ，Dohi T ，Oota H ，Hattori M ... -  《-》

Dysbiosis in the Gut Microbiota in Patients with Inflammatory Bowel Disease during Remission.

Pisani A ，Rausch P ，Bang C ，Ellul S ，Tabone T ，Marantidis Cordina C ，Zahra G ，Franke A ，Ellul P ... -  《Microbiology Spectrum》

Deciphering salivary microbiome signature in Crohn's disease patients with different factors contributing to dysbiosis.

Elzayat H ，Malik T ，Al-Awadhi H ，Taha M ，Elghazali G ，Al-Marzooq F ... -  《Scientific Reports》