CAISATION ()!•■ ANIMAL I )|SI;AS1<;S 



255 



lute roquironuMit in the (li;it;ii()sis of ;ictiii()- 

 niycosis. In isoint iiii:; pin'c (•iillurcs, Colc- 

 brook used the nuMliod of (Jordoii, which 

 consisted of ini|)i;inl ini;- a f^ranule inlo a lulx' 

 of l)loo(l-l)r()th nnder an oil seal. (Irowth of 

 the orj2;anisnis was al\va>s slow, th(> primary 

 culture re(iuirin<j; 'A to 8 days and sulx'ultures 

 2 to () days. (Irowtli iiexcr occuri-ed at 22°C. 

 All strains isolated showed j)refei-en('e for 

 anaei'ohic f;rowth, hut se\'eral were capalile 

 of aerobic growth after some subculturing. 

 Occasionally, even primary aerobic cultures 

 were obtained after JO to 14 days' incuba- 

 tion. Th(> ori^anism isolated from 2] cases 

 was dt'finitely of the .1 . hovis type. It showed 

 coarse agy;lutination with the serum of heav- 

 ily infected patients, as well as with the se- 

 rum of infected rabbits. Colebrook dismissed 

 the idea that infection with such a fragik" 

 organism and of such slight viability could 

 occur from outside "natural" sources, as 

 claimed by Bcxstroem and others. He con- 

 sidered the organism as a common inhabitant 

 of the human alimentary tract. 



Lieske tried to justify the apparently con- 

 flicting observations on the aerobic and an- 

 aerobic organisms by emphasizing the fact 

 that the anaerobic forms tend to become aer- 

 obic after several subcultures. This led him 

 to suggest that one type might be converted 

 into the other. 



Xaeslund (1931) finally established the 

 fact that the great majority of actinomycosis 

 cases are caused by a preferentially anaerobic 

 organism. Certain cases, however, affecting 

 the lung and skin maj' be caused by aerobes, 

 which come from the inhalation of dust con- 

 taining the organism (Biggart). 



Cope suggested recognition, for clinical 

 purposes, of two main groups of actinomy- 

 cetes : 



1. A very large gi'oup including those 

 forms which grow in the natural state in soil 

 and on organic residues. These ai"e hardy 

 organisms growing casilj^ and c|uickly at 



Fua RE 100. A', asleroulea on nutrient agar 

 (Reproduced from: Kirby, W. M. M. and AIc- 

 Naught, J. B. Arch. Internal Med. 78: S, 1946). 



room temperature on all ordinary media in 

 the ordinary atmosphere. The}' are then 

 aerobic in nature. Very few of them are path- 

 ogenic. 



2. Those that are preferentially anaerobic. 

 They comprise a much smaller group. Clin- 

 ically they are more impoitant. They are 

 much more delicate and more difficult to 

 grow than the aerobic type. They grow best 

 in the absence of oxygen or with only a 

 limited supply. They are not found outside 

 the body, and are responsible for nine-tenths 

 of the cases of actinomycosis in man. 



The first group comprises those organisms 

 that are now recognized as members of the 

 genera Nocardia and Streptomyces. Numer- 

 ous reports are found in the literature con- 

 cerning the isolation, from human or animal 

 blood or pus, of actinomycetes belonging to 

 this group. Many investigators were inclined 

 to consider them largely as dust contam- 

 inants. Some (Thjotta and Gundersen) 

 looked upon them not as etiologic agents of 

 particular diseases but as saprophytes found 

 in the respiratory tract (in the throat and 

 on the tonsils) and gaining entrance into the 

 blood of the patient when the body defenses 

 were low. 



