Protective Factors in the Intestinal Microbiome Against Clostridium difficile infection in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation.

Background: Clostridium difficile infection (CDI) is a frequent complication in recipients of allogeneic hematopoietic stem cell transplantation (allo-HSCT), who receive intensive treatments that significantly disrupt the intestinal microbiota. In this study, we examined the microbiota composition of allo-HSCT recipients to identify bacterial colonizers that confer protection against CDI following engraftment.

Methods: Feces collected from adult recipients allo-HSCT at engraftment were analyzed; 16S rRNA genes were sequenced and analyzed from each sample. Bacterial taxa with protective effects against development of CDI were identified by linear discriminant analysis effect size analysis, then further assessed with clinical predictors of CDI using survival analysis.

Results: 234 allo-HSCT cases were studied; 53 (22.6%) developed post-engraftment CDI. Within the composition of the microbiota, the presence of three distinct bacterial taxa were correlated with protection against CDI: Bacteroidetes, Lachnospiraceae, and Ruminococcaceae. Colonization with these groups at engraftment was associated with a 60% lower risk of CDI, independent of clinical factors.

Conclusions: Colonization with these three bacterial groups is associated with lower risk of CDI. These groups have been shown to be vital components of the intestinal microbiota. Targeted efforts to maintain these established groups may serve to minimize the risk of CDI in this at-risk population.