THE GENUS NOCARDIA 



23 



3K 



1 "<*aJ 



Figure 7. A', opaca: (a) grown for 4 days on ra-dodecane and mineral salts; gram stain, X 960; b 

 same grown 3 days; X 3700; (c) same as (a) bu1 using fat stain. X L920; (d) two-day growth, X 12,500 

 CReproducedfrom:Webley, D. M. J. Gen. Microbiol. 11:425, 1954). 



smooth, folded or wrinkled. Typical nocar- 

 dias never form an aerial mycelium, but 

 there are cull tire- whose colonies are covered 

 with a thin coating of shorl aerial hyphae 

 which break up into cylindrical oidiospores.* 

 Many species of nocardias form pigments; 

 their colonies are of a blue, violet, red, 

 yellow or green color; more often the cull tires 

 are colorless. The color of the culture serves 

 as a stable character. The type species is 

 A ocardia farcinica Trevisan.'"' 



Classification of Nocardia Species 



De Toni and Trevisan (1889) described 

 five species of Nocardia: X. farcinica, N. 

 actinomyces, N. foersteri, X. arborescens, and 

 A'. /« rruginea. 



* Sec the work of < rordon and Mihm (1958). 



Jensen (1932a) found that a number of 

 organisms previously described a- species of 

 Mycobacterium actually belong, on account 

 of definite mycelial growth in the initial 

 stages of their life cycles, to the feints Nocar- 

 dia* Mycobacterium agreste ( rray and Thorn- 

 ion and B. mycoides corallinus Befferan were 

 found to be similar to one another and were 

 regarded as one species. A', corallina. The 

 -.■one was true of .1/. salmonicolor den I )ooren 

 de Jong, which was designated as N. sal- 

 monicolor. Mycobacterium opacum den 

 Dooren de Jong and .1/. crystallophagum 

 Gray and Thornton proved to be identical 

 and were named N. opaca. Mycobacterium 

 erythropolis, a closely related form, was des- 



• I reneric name Proa< nomyces used. 



