ACTINOBAOILLUS 389 



Type I consists morphologically of branching, and often very sinuous, relatively short 

 threads, usually arranged in a radiating fashion ; rods and granules are also present. 

 In old cultures there is marked pleomorphism. No aerial spores. Chiefly Gram-positive, 

 non-acid-fast. Culturally, growth in dextrose broth occurs in the form of round, oval, or 

 ovoid colonies, white to yellowish-grey in colour, which appear at the bottom in about 

 a week. On saliva dextrose agar a sUghtly shiny colourless film appears, becoming granular 

 after a few days ; some of the granules may develop into small greyish-white nodular 

 adherent colonies, having a narrow translucent, finely striated margin. Little or no growth 

 on gelatin, potato or milk. Optimum temperature for growth 37° C. ; no definite growth 

 at 20° C. 



Type II consists of very long threads of fairly even thickness, showing typical but 

 infrequent branching. No definite aerial spores formed. Gram-positive, but the greater 

 part of the mycelium consists of Gram-negative elements with occasional Gram-positive 

 segments. Non-acid-fast. Culturally, in saliva dextrose broth round, greyish, more or 

 less translucent colonies develop at the bottom in about a couple of weeks. On saliva 

 glucose agar growth at first occurs in a thin film, but in 1 to 2 weeks isolated pinhead 

 colonies appear, hard or soft in consistence, and surrounded by a narrow translucent 

 border. No definite growth on gelatin, potato, or in milk. 



ACTINOBAOILLUS 



Lignieres and Spitz (1902) isolated a non-motile, non-branching, Gram-negative 

 bacillus from the lesions of cattle suffering from a disease which in many respects 

 resembled actinomycosis. They called the organism the actinobacillus, and the 

 disease to which it gave rise actihobacillosis. Two other organisms have since 

 been described, having some points of similarity with this bacillus, and it is there- 

 fore convenient to consider them as forming a group to which the generic name 

 Actinobacillus may be applied. 



Definition. Actinobacillus Brumpt. (Emended from the American Committee's 

 Report. ) 



Gram-negative, non-acid-fast rods, sometimes occurring in long chains or in 

 unjointed filaments. In lesions in the animal body no mycelium is formed, but 

 at the periphery finger-shaped cells or clubs may be visible. 

 Type species is Actinobacillus lignieresi, Brumpt. 



The classification we suggest is as follows : 

 Actinobacillus. 



A. Aerobic and facultatively anaerobic. Actinobacillus lignieresi. 



Actinobacillus actinomycetem- 

 comitans. 



B. Preferring raised COg pressure. Actinobacillus actinoides. 

 A description follows of the separate organisms. 



Actinobacillus lignieresi 



For isolation see above. Appears to be a strict parasite. 



Synonym. — Probably the sa;me as Bad. purifaciens (see TumiicUff 1941). 



Morphology. — In young cultures it is a small rod-shaped organism ; in older cultures 

 it is cocco-bacillary, and various involution forms appear. In serum broth long 

 streptobacillary forms are common. In glucose agar shake cultures long, tangled, 

 unbranched filaments may be formed, accompanied by smaller bacilli and coccoid 

 bodies (Griffith 191iB). Dimensions of the bacilli are given by Lignieres and Spitz 

 (1902) as 1-15-1 -25 /x long by 0-4 pi broad. Non-motile; non-sporing ; non-acid- 

 fast. Stains readily, especially with carbol fuchsin, and is Gram-negative ; 

 frequently shows bipolar staining. 



