Collateral damage during antibiotic treatment of C. difficile infection in the aged host: Insights into why recurrent disease happens.

Clostridium difficile infection (CDI) is one of the most common causes of healthcare-associated infections but an even bigger problem for the aging population. Advanced age leads to higher incidence, higher mortality, and higher recurrences. In our study, recently published in the Journal of Infectious Diseases, we investigated the effect of aging on CDI using a mouse model. We were able to demonstrate that aging leads to worse clinical outcomes, as well as lead to changes in microbiota composition and lower antibody production against C. difficile toxin A, but not toxin B. An association between advanced age and lower antibody production against C. difficile is a new finding which would explain the effect of aging on CDI outcome. Vancomycin, an anti-C. difficile antibiotic, led to similar changes in antibody response, suggesting a connection between microbiome and antibody response in the context of aging, which would require a much more nuanced look at the treatment of CDI.