Fecal Freezing Preservation Period Influences Colonization Ability for Fecal Microbiota Transplantation.

AIMS: There has been growing interest in fecal microbiota transplantation (FMT) as treatment. Although, frozen donor feces preserved at -20°C has been widely used for practical advantages, freezing at -20°C can affect bacterial viability. Adequacy evaluation of fresh and frozen feces as the transplant is necessary for the methodological improvement of FMT.

METHODS AND RESULTS: The viable bacterial compositions of fecal specimens under fresh and freezing conditions were compared by a microbiome analysis using propidium monoazide (PMA microbiome). In addition, recovery abilities from bacterial reduction by antibiotics were compared between fresh and frozen FMT using a murine model. PMA microbiome results suggested that freezing and freeze-thawing didn't significantly affect in vitro fecal bacterial viability. However, the recovery effect from antimicrobial cleansing in frozen FMT was reduced in a freezing time-dependent manner, especially prominent in Actinobacteria and Bacteroidetes phyla.

CONCLUSIONS: Short-term freezing preservation of feces exhibited maintenance of enteric colonization ability in frozen FMT in comparison to 1 month -20°C-preservation.

SIGNIFICANCE AND IMPACT: Long-term -20°C-preservation of transplanted feces can result in instability of the clinical outcome in FMT therapy. The standardization of practical procedures of FMT therapy according to disease types is desirable. This article is protected by copyright. All rights reserved.