Fecal microbiota of murine model of CDI relapse

This project investigated the dynamics of the gut microbiota and C. difficile infection (CDI) in a murine model of recurrent CDI. Mice were rendered susceptible to C. difficile with a 5-day course of cefoperazone (days -7 to -5). On day 0, mice were infected with C. difficile strain 630 spores, which resulted in clinical signs of CDI at days 3 and 4 post-infection (pi). On day 4 pi, mice were treated with vancomycin for 5 days (days 4-9 pi). Within seven days of cessation of vancomycin, mice displayed signs of CDI relapse (day 16 pi). A subset of mice was treated with fecal microbiota transplantation (FMT) within three days of cessation of vancomycin treatment to test whether FMT prevented relapse. FMT-treated mice cleared C. difficile colonization, and were resistant to reacquisition of C. difficile even after subsequent perturbation with an intraperitoneal injection of clindamycin (day 35 pi). Although FMT mice eventually cleared C. difficile, they displayed clinical signs of CDI similar to non-FMT mice. Mice that did not receive FMT remained colonized and susceptible to expansion of C. difficile. This project emphasizes the importance of consideration for recovery of the microbiota during recurrent CDI.