FAMILY I. MYCOBACTERIACEAE 707 



cells produce lepromin reactions in lepro- leprosy-like acid-fast bacilli that have not 



matous humans. The bacilli from lesions are yet been cultivated on artificial media, 



not bound together in clumps, rounded Source: An endemic disease of rats in 



masses and palisades as in human lesions. various parts of the world, having been 



For further details, see review by Lowe found in Odessa, Berlin, London, New 



(Internat. Jour. Leprosy, 5, 1937, 310 and South Wales, Hawaii, San Francisco and 



463). elsewhere. 



Comment: Nodular diseases of the skin Habitat: The natural disease occurs 



of other animals have been described, e.g. a chiefly in the skin and lymph nodes, caus- 



disease of the buffalo in India and of the ing induration, alopecia (loss of hair) and 



frog in South America, which are caused by eventually ulceration. 



Genus II. Mycococcus Krassilnikov, 1938* 



(Krassilnikov, Microbiologia (Russian), 7, Part 1, 1938, 335; also see Ray Fungi and Related 



Organisms, Izd. Akad. Nauk, U.S.S.R., Moskau, 1938, 121, Guide to the Actinomycetes, 



Izd. Akad. Nauk, U.S.S.R., Moskau, 1941, 122, and Guide to the Bacteria and 



Actinomycetes, Izd. Akad. Nauk, U.S.S.R., Moskau, 1949, 198; not Mycococcus 



Bokor, Arch. f. Mikrobiol., /, 1930, 1.) 



My'co. coccus. Gr. noun myces a fungus; Gr. noun coccus a berry, a sphere; M.L. mas.n. 

 Mycococcus coccus-shaped fungus. 



Cells generally spherical, occurring singly, in short chains or in clumps; rod-shaped cells 

 also occur, particularly in potato and liquid media. The spherical cells are quite variable 

 in size and shape, the smaller cocci measuring 0.2 to 0.5 micron in diameter, and the larger 

 cells (involution forms) measuring 0.7 to 1.0 micron in diameter; occasional cells are angu- 

 lar or ameboid in shape. The length of the rod-shaped cells ordinarily does not exceed twice 

 the width. Multiplication is by fission, constriction or bud formation. Resting cells, which 

 are produced from vegetative, coccus-like cells, germinate in a manner analogous to that 

 of the spores of the Actinomycetes, forming one to three germ tubes on their surface. Not 

 acid-fast. Gram-positive. Grow well on ordinary culture media. Gross appearance of colo- 

 nies similar to those of the genus Mycobacterium; red, yellow-green or orange pigments are 

 produced. Aerobic. Found widely distributed in soils. 



The type species is Mycococcus albus Krassilnikov. 



Key to the species of genus Mycococcus.f 



I. Non-chromogenic. 



A. Proteolytic property strong. Milk coagulated and peptonized. 



1. Mycococcus albus. 



B. Proteolytic property weak. 



1. Milk slowly coagulated, becoming slightly alkaline; weakly peptonized. 



la. Mycococcus albus subsp. albidus. 



2. Milk rapidly coagulated, becoming slightly acid; not peptonized. 



lb. Mycococcus albus subsp. lactis. 

 II. Chromogenic. 



A. Chromogenesis red, orange or rust. 



1. Colonies with dough-like consistency. 



a. Cells occur singly, in pairs or in chains 3 to 4 microns in length. 



2. Mycococcus ruber. 



* Prepared by Miss Lois Nellis, Hobart College, Geneva, New York, from a translation 

 made by Prof. S. A. Waksman, Rutgers University, New Bnmswick, New Jersey, Decem- 

 ber, 1954. 



t Key based on a table by Krassilnikov, Guide to the Actinomycetes, Izd. Akad. Nauk, 

 U.S.S.R., Moskau, 1941, 123. 



