A new study has revealed a cluster of factors that may help predict which patients are likely to develop Clostridioides difficile, commonly known as C. difficile or C. diff. The study involved the transplant of feces from human study participants to mice to assess differences in susceptibility to C. difficile infection. The study’s co-lead author, Vanessa Hale, assistant professor of veterinary preventative medicine at Ohio State’s College of Veterinary Medicine, examined the critical role that gut microbiota play in defending against the potentially life-threatening disease.
The researchers looked the gut microbes of 115 people who had diarrhea but did not have C. diff when they first sought medical care, as well as the gut microbes of 118 healthy volunteers. Approximately half of the patients with diarrhea had healthy looking gut microbial communities, while the other half revealed different microbes with very different levels of metabolites which the group called unhealthy or ‘dysbiotic’ communities.
“When we transplanted human stool from the dysbiotic group into mice, we discovered that these mice were more likely to become infected with C. diff than mice that received human stool from the healthy-looking group,” Hale said.
Through an examination of potential risk factors noted on the medical charts of individuals with both dysbiotic and healthy-looking gut microbial communities, researchers identified several factors associated with the dysbiotic communities that presented a clear connection between the risk factors and subsequent C. diff infection:
- Recent antibiotic use
- Suppressed immune function
- Current or recent hospitalization
- Prior C. difficile infection
Higher levels of amino acids, particularly proline, were also found in the guts of mice that received transplants from the participants with unhealthy gut communities. C. diff needs amino acids to multiply, prompting the interest of the researchers to study further the connection between reducing dietary amino acids and protecting at-risk humans from infection.
Furthermore, the study revealed that fecal transplantation from a healthy donor could protect against C. diff in mice prone to the infection. The U.S. Food and Drug Administration currently only allows this for the treatment of recurrent C. diff for those who don’t respond to conventional therapies. Hale said that it is unlikely that fecal transplantation would quickly be adopted as a prevention strategy, but that this study could help health care providers red-flag those patients who are at high risk of C. diff, leading to therapeutic or dietary interventions to lower the chances of infection.