Safety evaluation of Akkermansia massiliensis sp. nov. DSM 33459.

A novel strain of Akkermansia massiliensis sp. nov., designated as DSM 33459, was isolated from the feces of a healthy human donor. In order to fully assess the safety of this strain, following previously performed full genomic assessment, further in-vitro characterization and a combined in-vivo subchronic 28-day and 90-day toxicity study is reported herein. A. massiliensis DSM 33459 is tolerant to bile, somewhat tolerant to gastric juice pH conditions, and does not exhibit any aspects of virulence. This strain also demonstrates the ability to engraft the gastrointestinal tract of rats, persisting with continuous administration of the strain until the end of the study. Exposure to 2000 mg/kg BW/day A. massiliensis DSM 33459 did not produce any evidence of toxicity after either 28- or 90-days of exposure and did not translocate across the gastrointestinal barrier. Therefore, the NOEL for A. massiliensis DSM 33459, administered for 28- or 90-days, was determined to be the limit dose at 2000 mg/kg/day in male and female rats, a level which meets or exceeds calculated dose equivalent of 5.62 × 10¹¹ CFU/kg/day.