42 



THE ACTINOMYCETES, Vol. II 



preparations never showed a richly branch- 

 ing character, bu1 an alternate type of 

 branching was fairly easy to demonstrate 

 after about 7 days' incubation at 37°C. The 

 coccoid forms were round, oval, or drop- 

 shaped. Neither septa nor nuclei were seen. 

 Spores were formed in short chains within 

 mycelial strands and were of the same diame- 

 ter as the mycelial strands. Similar spores 

 were also found singly and extracellularly. 

 The organisms taken from cultures were 

 partially acid-fast . 



Growth on agar media: Colonies were slow 

 growing, appearing after 2 to 3 days as tiny 

 specks, which after 7 days' incubation finally 

 achieved, but. never exceeded, a size of about 

 1 mm in diameter. To the naked eye they 

 appeared grayish- white, compact, and 

 smooth, and under low-power magnification 

 they appeared fluffy, raised, compact at the 

 center, and irregular and stringy at the edge, 

 due to the presence of radiating and tangled 

 filaments. Zigzag arrangements of elements 

 and branches, clubs, and curls were seen at 

 the periphery. The colonies were adherent 

 to the medium. The top surface was dry and 

 could be scraped off with a stiff wire loop, 

 but neither the whole colony nor any part 

 of it could be removed intact. On blood agar 

 after 7 days' incubation, the colonies viewed 

 by transmitted light showed a characteristic 

 dense reddish center and a clear outer zone, 

 both areas being very sharply defined. 



Optimum temperature: 37°C. 



Oxygen requirements: The organism is a 

 facultative anaerobe, growing equally well in 

 the presence or absence of oxygen. 



Proteolytic activity: The organism is non- 

 proteolytic. No odor of putrefaction was 

 perceived in any of the cultures; gelatin was 

 not liquefied; no growth occurred on serum 

 plates or on coagulated human serum. 



Gelatin stab: No growth after 28 days at 

 17-20°C. 



Potato: No growth at 37°C. 



( 'arbon sources: Acid formed from glucose; 



not from lactose, sucrose, maltose, or glyc- 

 erol. 



Nitrate reduction: Negative. 



Habitat: Isolated from penile ulcer. 



Remarks: N. fastidiosa is different from 

 previously described species of Nocardia in 

 the following ways: It is very fastidious in 

 its growth requirements. It does not grow 

 in synthetic media to which carbohydrates 

 have been added; it will not utilize paraffin; 

 it will not grow on potato or carrot ; it will 

 not grow on acid-maltose agar nor on acid- 

 glucose agar; attempts to grow it on nutrient 

 agar and on BHI agar have given variable 

 results; its optimum temperature is 37°C. It 

 is delicate and is relatively slow growing; it 

 is never hardy or richly branching, and it 

 does not produce a surface scum or a con- 

 fluent or filiform growth. It is a facultative 

 anaerobe, differing in this respect from all 

 other Nocardias described with the excep- 

 tion of N. farcinica and .V. rubropertincta. 



The author summarizes its distinctive 

 properties as follows: It produces a fairly 

 compact colony composed of tangled myce- 

 lium and exhibits radiating, clubbed, 

 branched, and curled elements at the per- 

 iphery. Fragmentation of the mycelium and 

 post-fission movement (zigzag arrangement) 

 occur at the periphery of the colony. Arthro- 

 spores are produced. Stained preparations re- 

 veal partial fragmentation into bacillarv 

 and coccoid forms. Mycelial forms and spores 

 average slightly less than 1 ^ in diameter. 

 Neither nuclei nor septa were observed. 

 Branching is of an alternate type. It is par- 

 tially acid-fasi . 



20. Nocardia fiava (Krassilnikov, 1938) 

 Waksman and Henrici, 1948 (Krassilnikov, 

 N. A. Bull. Acad. Sci. USSR No. 1: L39, 

 1938). 



Not Proactinomyces flavus Humm and 

 Shepard . 



Morphology: Cells at first filamentous, 

 0.7 to 0.8 n in diameter; later, they break 

 into long rods and then into cocci 0.7 m in 



