Background: Fecal microbial transplantation (FMT) is the transfer of feces from a healthy donor into the gastrointestinal tract of a diseased recipient to confer a health benefit. The mechanism in which FMT confers a health benefit is linked to the viability and engraftment of microbes and the correction of dysbiosis.
Objectives: Our study aims to quantitate the colony forming units (CFUs) of microbes within feline FMT products using culture-based techniques in aerobic and anaerobic environments.
Animals: Three screened healthy feline fecal donors each provided three separate fresh fecal samples for processing.
Methods: Fecal processing techniques include unprocessed and three double-centrifuged fecal slurries with the following additives: 0.9% saline, 10% glycerol, and 25% maltodextrin and trehalose (M:D). FMT products were aliquoted for long-term storage at -20C, -80C, and lyophilized for storage at room temperature. Timepoints for CFU/gram quantitation include baseline, 1-, 3-, 6-, and 12-months.
Results: Across all storage conditions, FMT products preserved with M:D exhibited the lowest mean log10 drop over 12-months. All FMT products, except 10% glycerol and 25% M:D frozen at -80C, exhibited significant decreases in total CFUs over 12-months (p<0.01). For all FMT products, storage at -80C yielded significantly more total CFUs than storage at -20C (p<0.01).
Conclusions and clinical importance: M:D is the superior cryopreservative for feline FMT across all storage conditions. This study provides clinicians with evidence for producing and storing FMT in their own practice. Further research is needed to determine whether increased CFUs translates to microbe engraftment and thus additional clinical benefit.
