mycobacterium gadium mycobacterium gadium mycobacterium gadium is a species of the phylum actinomycetota (gram-positive bacteria with high guanine and cytosine content, one of the dominant phyla of all bacteria), belonging to the genus mycobacterium. mycobacterium gadium scientific classification domain: bacteria phylum: actinomycetota class: actinomycetia order: mycobacteriales family: mycobacteriaceae genus: mycobacterium species: m. gadium binomial name mycobacterium gadiumcasal and calero 1974, atcc 27726 description short gram-positive, nonmotile and acid-fast rods. colony characteristics yellow-orange, scotochromogenic colonies, but the pigmentation deepens with exposure to light. older cultures are more dry and rough. physiology rapid growth on löwenstein-jensen medium at 28 °c and 37 °c, but not at 45 °c. pathogenesis pathogenicity in humans is not known. production of a local regressing infection but no death in mice. biosafety level 1 type strain first isolated from known tuberculous patient from cadiz, spain. strain atcc 27726 = ccug 37515 = cip 105388 = dsm 44077 = hambi 2274 = jcm 12688 = nctc 10942.