Description of 

 Species of Actinomyces 



1. Actinomyces bovis Harz. (Harz, C. 0., in Bollinger, 0., Centrbl. 

 Med. Wiss., 15, 1877, 485; Jahr. Munch. Thierarzeneisch., 1877, 781.) 



Growth: No aerial hyphae. Radiate, sulfur-colored granules occur in the 

 pus found in cases of actinomycosis. Large, club-shaped hyphae are seen 

 in morbid tissues. Gram-positive. Nonmotile. Not acid-fast. Colonies 

 smoother and softer in consistency, and more uniform than in the follow- 

 ing species. The colonies are not adherent to the medium and growth is 

 scantier. 



Sporulation : Mycelium undergoes fragmentation very rapidly, extensive 

 branching is rare; hyphae less than lju in diameter. 



Semisolid media: Excellent growth, especially with paraffin seal. 



Gelatin: Occasionally scant, flaky growth. No liquefaction. 



Liquid media: Occasional turbidity with a light, flocculent growth. 



Pigments: No soluble pigments produced on protein media. No insoluble 

 pigments produced by growth. 



Egg or serum media. No proteolytic action. 



Milk: Becomes acid but usually no coagulation, no peptonization. Some- 

 times no growth. 



Temperature: Optimum 37°C. 



Remarks: Anaerobic to microaerophilic. Bovine strains are more oxygen- 

 tolerant on egg or serum media than strains of human origin belonging to 

 the following species. Acid from glucose, sucrose, and maltose. No acid 

 from salicin and mannitol. 



2. Actinomyces israeli (Kruse) Lachner-Sandoval. (Strahlenpilze. 

 Wolff and Israel, Arch. Pathol. Anat., 126, 1891, 11.) 



Growth: Erect aerial hyphae produced in an atmosphere of reduced 

 oxygen tension. These hyphae are occasionally septate, but no definite 

 spores are formed. One micron or more in diameter. Large club-shaped 

 forms are seen in morbid tissues. Gram-positive. Nonmotile. Not acid-fast. 



Substrate mycelium initially unicellular and the branches may extend 

 into the medium in long filaments or may, more or less quickly, exhibit 

 fragmentation and characteristic angular branching. The latter resembles 

 the phenomenon found in Corynebaderium. 



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