NR1H4 and type 2 diabetes mellitus: Beside A. muciniphila, additional specific bacteria were recently proposed as potential mediator of metformin action, but were not found in the present study, such as Lactobacillus members, that are increased after 1 day of metformin treatment in rat duodenum31, and Bacteroides fragilis which is decreased after 3 days of metformin in the stools of T2DM patients and that may regulate FXR signalling through the production of the bile acid GUDCA21.