numidum numidum numidum is a gram-positive and facultative anaerobic genus of bacteria from the family of bacillaceae with one known species (numidum massiliense) which has been isolated from the human gut. numidum scientific classification domain: bacteria phylum: bacillota class: bacilli order: bacillales family: bacillaceae genus: numidumtidjani alou et al. 2016 type species numidum massiliense species n. massiliense