Balancing the Body’s Bacterial Ecosystems

Bacteria living in the digestive tract – especially in the colon – can have a tremendous impact on human health and quality of life. Research has shown that a number of diseases – including diabetes and bowel dysfunctions such as colitis – are associated with changes in bacteria that live in the human digestive tract. Yet researchers are only now just beginning to understand these complex bacterial ecosystems inside our bodies.

Through a project funded by the National Institutes of Health and the CIPAC company, University of Minnesota researchers including BioTechnology Institute Director Michael Sadowsky and gastroenterologist Alex Khoruts are studying the role that different bacteria species play in the human intestinal tract using metagenomic approaches.

Sadowsky became interested in intestinal bacteria in 2008 when he and Khoruts were involved in an experimental treatment that utilized transplanted bacteria to cure a serious colon infection caused by Clostridium difficile. Characterized by severe recurrent diarrhea and the production of toxins, the infection resulted in an imbalance of intestinal bacteria. The C. difficile bacteria had taken hold after good bacteria in the patient’s colon had been decimated by antimicrobial medications. Sadowsky and Khoruts re-introduced good bacteria from a donor into the affected colon to re-establish a healthy balance in the colon’s bacterial ecosystem. This procedure, which was recently licensed by the CIPAC company for clinical trials pending FDA approval, has helped cure a large number of patients with similar infections.

“It was remarkable that so many patients were cured,” commented Sadowsky, “and that the patients’ intestinal bacteria resembled that of the donors’.”

C. difficile is a species of gram-positive anaerobic bacteria that forms spores which can pass through stomach acids and germinate into vegetative cells in the colon. Normally kept in check by other colon bacteria, they can multiply when antibiotics adversely affect bacteria necessary for digestion and for maintaining good health. The team of University researchers have been trying to identify and map the genetic structure of intestinal microorganisms that may be protective against diseases associated with C. difficile, and they have now produced a partially purified frozen bacteria preparation that is curative after 11 months in the freezer.

“If we can isolate DNA from all the intestinal microorganisms,” concluded Sadowsky, “we can use it to understand who the players are and determine their functions in maintaining a healthy and functional gastro-intestinal tract.”

-Tim Montgomery