Clostridium difficile: deleterious impact on hematopoietic stem cell transplantation.

C. difficile infection (CDI), the most common cause of hospital-acquired diarrhea, is very frequent after hematopoietic stem cell transplantation (HSCT). Recent publications suggest it affects between 6 % and 20 % of HSCT recipients during the first year and is more common following allogeneic transplant (allo-HSCT). The best diagnostic strategy remains to be defined, but molecular testing for the toxin genes by polymerase chain reaction (PCR) seems to be replacing the traditional enzyme immunoassays (EIA). The higher sensitivity of the PCR may result in increased measured incidence of disease. C. difficile infection typically occurs during the first month after HSCT. Although the course of CDI after HSCT does not seem to be different than in other hospitalized patients, it may result in worsening of bowel graft versus host disease (GVHD) after allo-HSCT. Current evidence suggests a reciprocal effect by which GVHD may increase the risk of CDI and C. difficile disease may increase the risk of GVHD. Metronidazole was the treatment most commonly used in all recent series, followed by the combination metronidazole and oral vancomycin. There is minimal information on the use of fidaxomicin in HSCT recipients. Regarding stool transplant, there is one case report of successful use of this modality in an HSCT recipient. These two newer approaches will certainly be investigated in the future.