Can we prevent C. diff infections with other bacteria?

The microbiome of the mammalian gut helps protect the body from intestinal colonization of harmful pathogens. Antibiotic use can destroy the beneficial bacteria in our gut and allow for harmful bacteria to colonize it. Specifically, Clostridium difficile (C. diff) infection is a condition that is frequently seen in patients taking antibiotics and is often fatal.  A study published in Nature last week led by scientists at Memorial Sloan Kettering Cancer Center identified another bacteria, Clostridium scindens, that helped fight against C. diff infection. This study opens a new avenue to better predict what patients are at a higher risk of C. diff infection as well as the development of products that could prevent or even treat this condition.

A few weeks ago we wrote about an study published in the Journal of the American Medical Association that described the treatment of patients suffering from C. diff infection with a pill containing fecal material of healthy individuals.  The pill restored the microbiome to a healthy state and prevented future infection. However, little is known about what specific bacteria are responsible for resistance to infection. Why do some patients taking antibiotics get C. diff and others do not?

The scientists conducting this study identified 24 human patients undergoing allogeneic hematopoietic stem-cell transplantation, 12 who had C. diff infections and 12 who were C. diff carriers but were not infected after their transplant.  In the human study, as well as in mouse studies, they found that Clostridium scindens, an intestinal bacterium, is connected with resistance to C. diff infection. C. scindens produces an enzyme necessary for secondary bile acid synthesis, which was shown to be absent in the gut of patients infected with C. diff but present in recovered patients. This study suggests that it may be possible for doctors to better predict what patients are at a higher risk of C. diff infection by measuring the presence of C. scindens in the patient’s gut.  C. scindens could also be used in the development of preventative agents or therapeutics given to patients at higher risk or infected with C. diff.