 4) KT1 is 2 base-pairs different from the 16s ribosomal RNA gene (16sRNA) of "M. marinum" and 3 base-pairs different from "M. ulcerans".KT1 is a non-photochromogenic acid-fast mycobacterium.On Middlebrook 7H11 media supplemented with OADC, colonies are non-pigmented and slightly buff-colored, with rough morphology.