Standardized preparation of frozen, live and ready-to-use transplants for microbiotherapy - short-term storage

Owing to the growing recognition of the gut microbiota as a main partner of human health, we can expect the number of indications for microbiotherapy (fecal microbiota transplantation) to go up. Thus, there is an urgent need for standardization of the entire process of fecal transplant production. This study provides a complete standardized procedure to prepare and store live and ready-to-use transplants that meet the standard requirements of good practices to applied use in pharmaceutical industry. We show that, if time before transformation to transplants would exceed 24 h, fresh samples should not be exposed to temperatures above 20 °C, and refrigeration at 4 °C can be a safety solution. Oxygen-free atmosphere was not necessary and simply removing air above collected samples was sufficient to preserve viability. Transplants prepared in maltodextrin-trehalose solutions, stored at -80 °C and then rapidly thawed at 37 °C, retained the best revivification potential as proved by phylotranscriptomic profiles, metabolomic fingerprints, and flow cytometry assays over a 3-month observation period. Maltodextrin-trehalose containing cryoprotectants were also very efficient in preserving viability of lyophilized transplants, an option that can be very attractive for fecal transplant biobanking.