mycobacteria that grow rapidly and that do not produce pigment. Organisms placed in this group belong to such species as Mycobacterium ulcerans and M. marinum.
Run·yon group IV my·co·bac·te·ria
(rŭn'yŏn grūp mī'kō-bak-tēr'ē-ă) Mycobacteria that grow rapidly and do not produce pigment. Organisms placed in this group belong to such species as Mycobacterium fortuitum and M. chelonae.