Petragnani's medium: Primaiy growth visible in 4 weeks as minute, transparent, dome-shaped colonies; in older cultures colonies are low convex to flat with irregular outline and rough surface, lemon to mus- tard-yellow. Dorset's egg medium: Scanty growth, the colonies resembling those on Petragnani's medium, but there is little or no pigment. Glycerol broth: Growth onh' when colony fragments are used as the inoculum, form- ing white, irregular, floating balls; no pellicle formed. Glycerol: Low concentrations in most media enhance growth, especially in the later stages of growth. Optimum temperature, between 30° and 33° C. Very limited growth at 25° and 37°, and no growth at 41° C. Pathogenicity: Causes skin ulcers in man which are characterized by indolent exten- sion from areas of inconspicuous induration to involve large areas. Rats and mice are infected experimental!}' ; guinea pigs, rab- bits, fowls and lizards are resistant. E.xperi- mentally inoculated rats develop hemorrha- gic necrotic lesions surrounded bj' zones of cellular accumulations consisting of leuco- cytes, lymphocytes and macrophages. There are no giant cells. The necrotic and cellular zones show large clumps of acid-fast bacilli in the extra-cellular spaces and in macro- phages. Antigenic structure: In complement fixa- tion tests with sera of rabbits immunized with human, bovine and murine types of tubercle bacilli, Mycobacterium ranae and M. phlei, the heat-killed, washed bacilli serving as antigens, M. ulcerans was found to be antigenicallj' distinct from the other pathogenic species of Mycobacterium tested. This conclusion was supported by skin sen- sitivity reactions in guinea pigs (Fenner and Leach, op. cit., 30, 1952, 1; and Fenner, op. cit., 30, 1952, 11). Distinctive characters: Acid-fast bacilli; grows at 33° but not at 37° C; produces necrotic and ulcerative lesions in man, rats and mice without giant-cell formation; antigenically distinct from the other pathogenic species of Mycobacterium. Source: Isolated from ulcerative skin infections in man. Habitat : The apparent cause of skin ulcers in man. Transmissible to rats and mice. 8. Mycobacterium tuberculosis (Zopf, 1883) Lehmann and Neumann, 1896. (Tuberkelbacillen, Koch, Berl. klin. Wochn- schr., 19, 1882, 225; Bacterium tuberculosis Zopf, Die Spaltpilze, 1 Aufl., 1883, 67; Tu- berkelbacillen, Koch, Mitteil. a. d. kaiserl. Gesundheitsamte, 2, 1884, 6; Bacillus tuber- culosis Schroeter, in Cohn, Kryptogamen- Flora V. Schlesien, 3, 1886, 164; Human tubercle bacilli, Th. Smith, Trans. Assoc. Am. Phys., 11, 1896, 75; Lehmann and Neu- mann, Bakt. Diag., 1 Aufl., 2, 1896, 363; Mycobacteritim txibercxdosis tj^pus humanus Lehmann and Neumann, ibid., 4 Aufl., 2, 1907, 550; Mycobacterium tuberculosis var. hominis Bergey et al.. Manual, 4th ed., 1934, 536.) tu.ber.cu.lo'sis. L. dim. noun tuberculum a small swelling, tubercle; Gr. suffix -osis characterized by; M.L. fern. gen. n. tubercu- losis of tuberculosis. Common name: Human tubercle bacillus. Original description supplemented by material taken from Topley and Wilson (Princip. of Bact. and Immun., London, 2nded., 1936,315). Rods, ranging in size from 0.3 to 0.6 by 0.5 to 4.0 microns, straight or slightly curved, occurring singly and in occasional threads. Sometimes swollen, clavate or even branched. Stain uniformly or irregularly, showing banded or beaded forms. Acid-fast and acid -alcohol -fast. Gram-positive. Growth in all media is slow, requiring several weeks for development. This bacterium contains mycolic acid (Stodola, Lesuk and Anderson, Jour. Biol. Chem., 1S6, 1938, 505). The acid-fast mycolic acid combines more firmly with carbol- auramin than with carbol-fuchsin, and this apparently accounts for the increased sensi- tivity of fluorescence microscopy for this bacterium (Richards, Science, 93, 1941, 190; Richards, Kline and Leach, Amer. Rev. Tuberc, U, 1941, 255). Glycerol agar colonies: Raised, thick.
