Fecal microbial dynamics during recurrent and nonrecurrent Clostridium difficile infection

Recurrent Clostridium difficile infection (CDI) remains problematic, with up to 30% of individuals diagnosed with primary CDI experiencing at least one episode of recurrence. Microbial therapeutics, such as fecal microbiota transplantation, have been successful in treating patients, increasing the relative proportion of ‘healthy’ microbes. However, few studies have looked at what predisposes patients to recurrent disease initially. Our study investigated the fecal microbiota community over time in patients diagnosed with CDI. Using 16S rRNA sequencing, we sought to compare microbial changes over time in patients with or without recurrence and to identify microbial signatures that may correlate to the development of recurrence. We observed a trend towards lower diversity in samples collected from patients with recurrent disease over time. Although microbial community structure was similar between samples from recurrent and nonrecurrent patients, we observed a significantly different community structure between samples that tested positive or negative for C. difficile. Interestingly, patients with more severe disease had a lower diversity compared to healthier patients. To date, this study represents one of the largest studies focused on microbial signatures that may predispose individuals to recurrent CDI. Knowledge about microbial signatures that correlate with susceptibility to recurrent disease may lead to better treatment methods at initial CDI diagnosis.