FAMILY MYCOBACTERIACEAE 



883 



Rods: 3.0 to 5.0 microns in length with 

 slightly rounded ends. When stained, 

 often show irregular appearance. 

 Strongly acid-fast. Gram-positive. 



Like the human leprosy bacillus, this 

 organism has not been cultivated in 

 vitro; but can be passed experimentally 

 through rats and some strains of mice. 



Distinctive features: The heat-killed 

 bacilli produce lepromin reactions in 

 lepratomous humans. The bacilli from 

 lesions are not bound together in clumps, 

 rounded masses and palisades as in 

 hmnan lesions. For further details 

 see review by Lowe (Internat. Jour. 

 Leprosy, 5, 1937, 310 and 463). 



Source: An endemic disease of rats in 

 various parts of the world, having been 

 found in Odessa, Berlin, London, Xew 

 South Wales, Hawaii, San Francisco and 

 elsewhere. 



Habitat: The natural disease occurs 

 chiefly in the skin and lymph nodes, 

 causing induration, alopecia (loss of 

 hair) and eventually ulceration. 



6. Mycobacterium piscium Bergey et 

 al. {Bacillus tuberculosis ■piscium Du- 

 bard, Bull. acad. de med., 3 ser., 88, 

 1897, 580; Bataillon, Dubard and Terre, 

 C!ompt. rend. Soc. Biol., 4, ser. 10, 1897, 

 446; Bergey et al., Manual, 1st ed., 1923, 

 375.) From Latin piscis, fish. 



Description from Bataillon et al. {loc. 

 cit.) and Aronson (Jour. Inf. Dis., 39, 

 1926, 319). 



Slender rods, occurring singly and in 

 threads, occasionally showing branching. 

 Acid-fast. Non-motile. Gram-positive. 



Agar colonies : Small, circular, white, 

 moist, with lobate margin and fine 

 granular surface. 



Agar slant : Scant, white, moist, cream- 

 like. 



Glycerol agar colonies: Thin, flat, 

 smooth, glistening, yellow. 



Dorset's egg medium: Flat, smooth, 

 moist, greenish. 



Broth: Thin pellicle, with flocculent 

 sediment. 



Litmus milk: Thickened. No coagu- 

 lation. Slightly alkaline. 



Potato: White, warty, butyrous colo- 

 nies. 



Carbohydrates : Utilizes glucose and 

 fructose but not sucrose, lactose, arabi- 

 nose or galactose (IVIerrill, Jour. Bact., 20, 

 1930, 235, based on examination of one 

 strain). 



Antigenic structure : By agglutination 

 and complement fixation (Mudd, Proc. 

 Exp. Biol, and Med., 23, 1925, 569; and 

 Furth, Jour. Immunol., 12, 1926, 286) 

 Mycobacterium piscium has been dis- 

 tinguished from Mycobacterium fried- 

 mannii, Mycobacterium ranae and prob- 

 ably Mycobacterium marinum. From 

 the limited number of cultures examined 

 it is not evident whether this is due to 

 species or strain specificity. 



Pathogenicity : Experimentally pro- 

 duces tubercles in carp, frog and lizard, 

 but not pathogenic for rabbit, guinea pig 

 or birds (Dubard, Rev. de la Tuberc, 6, 

 1898, 13). Not pathogenic for salt water 

 fish except eels (Betegh, Cent. f. Bakt., 

 I Abt., Orig., 53, 1910, 374; 54, 1910, 

 211). 



Distinctive characters : Mycobacte- 

 rium piscium, Mycobacterium marinum, 

 Mycobacterium ranae, Mycobacterium 

 thamnopheos and Mycobacterium fried- 

 mannii constitute a closely related 

 group — possibly one species . They differ 

 from other members of the genus in their 

 pathogenicity for cold-blooded animals, 

 their failure to survive 60°C for an hour, 

 their failure to grow at 47°C and their 

 inability to utilize sorbitol. 



Mycobacterium marinum is distin- 

 guished by its diffuse gro'v\i;h in broth, 

 acid production in milk and deep yellow 

 to orange pigmentation on most media. 

 The other species grow in broth as a 

 pellicle and render milk alkaline. Myco- 

 bacterium piscium, Mycobacterium ranae, 

 Mycobacterium thamnopheos and Myco- 

 bacterium friedmannii may be distin- 

 guished from each other by their habit 

 of growth on solid media. But rela- 

 tively few cultures have been studied 



