title: In vitro cultivation of Mycobacterium X from Mycobacterium leprae-infected tissues in acetone-dimethylsulfoxide-tetradecane medium.
abstract: Several strains of mycobacteria were cultivable from Mycobacterium leprae-infected human and armadillo tissues in a liquid medium containing three dimethyl analogs: dimethylketone, dimethylsulfoxide, and tetradecane [CH3 . (CH2)12 . CH3]. The medium contained KH2PO4, 7.0 g; Na2HPO4, 1.0 g; (NH4)2SO4, 2.0 g; MgSO4, 0.1 g; iron ammonium citrate, 0.1 g; DMSO, 10 ml; and acetone, 150 ml in distilled water ad one liter. Tetradecane 0.1 ml was added aseptically to each tube, containing 10 ml of the sterile medium. The media, inoculated with M. leprae were incubated at 38 degrees C and shaken vigorously twice weekly. Growth developed as a fine emulsion at the upper phase of the two-phase system. This was homogenized by mechanical shaking, permitting growth estimation by turbidity measurements. Microscopic examination showed unmistakably the slow but abundant multiplication of acid-fast rods. The logarithmic growth rate was measurable during two to three months, followed by a plateau. The strains are maintained in subcultures by regular transfer into the same medium at two- to three-month intervals. The cultures and subcultures do not grow on Löwenstein or in Dubos media, but in the foot pads of mice they produce a multiplication similar to that obtained following injection of host-grown M. leprae. The cultures are tentatively designated as Mycobacterium X. The relationship of Mycobacterium X to the pathology of leprosy is not clear.
mesh_terms: D000096:Acetone; D000473:Alkanes; D000818:Animals; D001135:Armadillos; D003470:Culture Media; D004121:Dimethyl Sulfoxide; D006801:Humans; D007918:Leprosy / Q000382:microbiology* / Q000662:veterinary; D009161:Mycobacterium / Q000302:isolation & purification*
chemical_list: D000473:Alkanes; D003470:Culture Media; C024713:n-tetradecane; D000096:Acetone; D004121:Dimethyl Sulfoxide