A Vaccine for Clostridium difficile: What to Consider

Xingmin Sun, PhD, assistant professor, Molecular Medicine, University of South Florida, discusses aspects that need to be considered before developing a vaccine for Clostridium difficile.

Interview transcript (slightly modified for readability):

Clostridium difficile is a gram-positive toxin-producing spore-forming anaerobic bacteria. The major symptoms of the infection are intestinal inflammation and diarrhea. These effects are largely due to toxins. The major risk factor of infection is the disruption of the internal microflora caused by antibiotic therapy or by other means.

Currently, C difficile infection is listed by the US Centers for Disease Control and Prevention (CDC) as 1 of the top 3 urgent antibiotic resistance threats in the United States, causing about 50,000 infections and 29,000 deaths each year. It is a serious problem in the United States.

When we are developing a vaccine [against this pathogen] we have to think about several aspects. First, we need to think about the major virulent factors we need to target, and we need to think about the symptoms of the disease. We [also] need to think about immunization routes—intramuscular or mucosal—as well as the target population.

Considering C difficile infections, [they are] enteric pathogens and we need to target the major virulent factors, which are the 2 toxins. In terms of the immunization route, we would prefer to use a mucosal route, in particular, the oral immunization route would be ideal because it is an enteric pathogen and the disease is in the intestines.