Bacterial strain differences associated with inflammatory bowel disease
Bacterial strain differences associated with inflammatory bowel disease
Human gut bacteria play a crucial role in maintaining overall health. Changes in the composition of the human gut bacterial community can lead to several diseases, including inflammatory bowel disease (IBD). IBD encompasses a group of diseases characterized by chronic inflammation and a compromised epithelial barrier function of the intestines. Several IBD-related groups within Faecalibacterium and Mediterraneibacter have been identified, but the specific strain differences of these bacteria remain poorly understood.
In the thesis of Niels Plomp, bacterial strain differences of IBD-associated Faecalibacterium and Mediterraneibacter were investigated. To accommodate this, more than 5,000 bacteria were collected using efficient procedures developed for isolating and identifying bacteria. Approximately 1,400 of these isolated bacteria were obtained from IBD patients.
The novel species Faecalibacterium wellingii was described to produce extracellular polymeric substances. The extracellular polymeric substances of F. wellingii strain HTF-F stimulate cell proliferation and marker genes of the epithelial barrier in colonic epithelial cells. Furthermore, IBD-associated strains are more tolerant towards oxygen or reactive oxygen species. These strains have significantly more copies of genes related to oxidative stress.
Additionally, the global distribution of Mediterraneibacter gnavus was surveyed, which revealed a higher prevalence and relative abundance of this bacterial species in Westernized populations. A collection of high-quality genomes was also generated, which identified a Crohn’s disease-specific clade and specific enriched genes in this clade.
This thesis describes strain differences, which provide a mechanism to adapt to different intestinal environments and potentially have an important impact on the gut barrier integrity during health and IBD.