IS 



THE ACTINOMYCETES, Vol. II 





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Figure 5. .4. israelii (Reproduced from: Pre- 

 vot, A. R. 6th Intern. Congr. Microbiol., Symp. 

 Actinomycetales, Rome, 1953, p. 45). 



scribed first by Wolff and Israel (1891) and 

 later by Wright (1905). 



Remarks: Vitality weak. Cultures no 

 longer viable after 8 to 10 days. Erikson and 

 Porteous (1953) succeeded in obtaining good 

 growth by continued subculture in a medium 

 containing 99 parts of 1 per cent casein hy- 

 drolyzate and 1 part of heart broth and 0.5 

 per cent glucose. Antigenic structure of or- 

 ganism has been recently studied by Kwa- 

 pinski (19(30). 



According to Grootten (1934), the organ- 

 ism is highly polymorphic. Rods varying in 

 length are formed in young culture. They are 

 straight or slightly curved, with round or 

 oval extremities. Occasionally, long or even 

 filamentous forms are found. Some of the 

 filaments end in small spherical or pear- 

 shaped swellings. It does not form spores. 

 In agar tubes, it does not grow in the upper 

 5- to 10-mm zone; below that zone, it forms 

 a layer of 2 to 4 mm with numerous small 

 colonies; in the deeper layers, the colonies 

 are fewer, but may attain diameters of 2 to 3 

 nun. \<> gas and no odor are produced. 

 Liquid media remain clear. The organism is 

 nonproteolytic; milk is not coagulated. Blood 



is rapidly hemolyzed. It does not grow on 

 potato plugs, except poorly when glycerin- 

 ated. It slowly attacks glucose, lactose, mal- 

 tose, sucrose, and mannitol. It does not grow 

 in glucose-gelatin medium. Animal infection 

 is obtained by introducing a culture into the 

 peritoneum of rabbits. 



Negroni (1954) described A. israelii in 

 further detail. Deep colonies in semisolid 

 glucose agar are globous, 1 to 2 mm in 

 diameter, whitish, opaque, and with an ir- 

 regular surface. Colonies are of a cheesy 

 consistency and cannot be homogeneously 

 suspended in water. On glucose or glycerol 

 agar slants, the colonies are elevated, mam- 

 milated, and whitish, with moist and bril- 

 liant surface and irregular margins. Sub- 

 merged mycelium is well developed. The 

 colonies have a cheesy consistency and can 

 easily be removed from the medium with a 

 platinum loop (Fig. 5). 



According to Erikson and Porteous (1955), 

 the conversion of a "rough" typical strain of 

 A. israelii to a "smooth" soft form more 

 tolerant of oxygen is a result of the physical 

 trapping within the mycelium of a few alien 

 facultative anaerobes, usually staphylococci. 



7. Actinomyces naeshmdii Thompson and 

 Lovestedt, 1951 (Thompson, L. and Love- 

 stedt, S. A. Proc. Staff Meet. Mayo Clinic 

 26: 169, 1951). 



Morphology: Organism forms small, whit- 

 ish, firm colonies. Mycelial branching, but no 

 segmentation. Not acid-fast. 



Artificial media: Good growth. 



Hormone agar: Rough and smooth colo- 

 nies, 1 to 2 mm in diameter, after 4 days. 

 Surface of colonies varies from smooth to 

 nodular to wrinkled. Consistency varies from 

 butyraceous to tough and adherent. Colo- 

 nies are opaque, with color varying from 

 white to cream. 



Glucose brain broth: Growth rapid and 

 abundant. Acid produced. 



Gelatin: Growth slow. Xo liquefaction. 



Starch: Not hydrolyzed. 



