A prior room occupant with CDI is a significant risk factor for CDI acquisition, independent of established CDI risk factors. These findings have implications for room placement and hospital design.

Fecal microbiota transplantation (FMT) is a highly effective therapy for recurrent Clostridium difficile infection (R-CDI), but its mechanisms remain poorly understood. Emerging evidence suggests that gut bile acids have significant influence on the physiology of C. difficile, and therefore on patient susceptibility to recurrent infection. We analyzed spore germination of 10 clinical C. difficile isolates exposed to combinations of bile acids present in patient feces before and after FMT. Bile acids at concentrations found in patients’ feces prior to FMT induced germination of C. difficile, although with variable potency across different strains. However, bile acids at concentrations found in patients after FMT did not induce germination and inhibited vegetative growth of all C. difficile strains. Sequencing of the newly identified germinant receptor in C. difficile, CspC, revealed a possible correspondence of variation in germination responses across isolates with mutations in this receptor. This may be related to interstrain variability in spore germination and vegetative growth in response to bile acids seen in this and other studies. These results support the idea that intra-colonic bile acids play a key mechanistic role in the success of FMT, and suggests that novel therapeutic alternatives for treatment of R-CDI may be developed by targeted manipulation of bile acid composition in the colon.

Goals Test whether ursodeoxycholic acid is inhibitory to Clostridium difficile and can be used in the treatment of C. difficile associated ileal pouchitis. Background Restoration of secondary bile metabolism may be the key mechanism for fecal microbiota transplantation (FMT) in treating recurrent C. difficile infections (RCDI). Therefore, it is possible that exogenous administration of inhibitory bile acids may be used directly as non-antibiotic therapeutics for this indication. The need for such a treatment alternative is especially great in patients with refractory C. difficile associated pouchitis, where the efficacy of FMT may be limited. Study We measured the ability of ursodeoxycholic acid (UDCA) to suppress germination and vegetative growth of 11 clinical isolate strains of C. difficile from patients treated with FMT for RCDI. In addition, we used oral UDCA to treat a patient with RCDI pouchitis that proved refractory to multiple antibiotic treatments and FMT. Results UDCA was found inhibitory to germination and vegetative growth of all C. difficile strains tested. Fecal concentrations of UDCA from the patient with RCDI pouchitis exceeded levels necessary to inhibit germination and growth of C. difficile in vitro. The patient has remained infection-free for over ten months following initiation of UDCA. Conclusions UDCA can be considered as a therapeutic option in patients with C. difficile associated pouchitis. Further studies need to be done to define the optimal dose and duration of such treatment. In addition, bile acid derivatives inhibitory to C. difficile that are able to achieve high intracolonic concentrations may be developed as therapeutics for RCDI colitis.