The role of gut bacteria in fighting diseases

Recently, the human gut microbiome has been a very active area of investigation. Research has shown that links exist between microbes in the human gut and health, creating a framework for human and animal microbiome research. These new insights suggest that the gut microbiome could play a crucial role in preventing and curing diseases, reducing the severity of gastrointestinal disorders, and digesting complex plant polysaccharides.

One important class of gut bacteria is spirochetes, a group of prokaryotes that can promote metabolism of fibrous components of plant cell walls in the bovine rumen, thereby aiding in the digestion and absorption of nutrients. Additionally, spirochetes are one of the few major bacterial groups whose natural phylogenetic relationships are evident at the phenotypic level. In order to understand the role these helical microorganisms play within the gut, a model microcosm system will be implemented, as well as the involvement of microbe isolation and characterization techniques.

Results of previously described research revealed that concentrations of the antibiotic rifampin may be used to enrich and isolate spirochete bacteria. Thus, 20μg/mL rifampin was added to nutrient-rich broth with cellobiose as growth substrate, and cultures were incubated under anaerobic conditions. After diluting enrichment cultures to extinction, two strains of spirochete bacteria were successfully isolated from microcosms derived from compost, and frozen stock cultures were prepared. The strains were characterized phylogenetically by sequencing their 16S rRNA genes. Cell morphology and motility were examined using phase-contrast microscopy. Growth was monitored by measuring the turbidity of cultures as the optical density at 660nm.

Currently, growth substrate range, temperature and pH range for growth, and antibiotic resistance of the spirochete isolates are being determined. The goal of this research is to test the hypothesis that spirochete members of the gut microbiome play a role in the nutrition and health of humans and other animals.