388 ACTINOMYCES 



peritoneal injection is fatal to guinea-pigs in 9 to 20 daj's ; post mortem, miliary nodules 

 over peritoneum, containing a little pus ; in the pus are masses of bacilli. Intravenous 

 injection of guinea-pigs causes the formation of generalized miliary nodules, particularly 

 abundant in the lungs, liver, and spleen. Miliary nodules follow intravenous injection 

 of cows and sheep. Rabbits, dogs, cats, horses, and asses are resistant to intravenous 

 or intraperitoneal injection. Subcutaneous injection causes a slowly progressive abscess, 

 which ulcerates and heals. 



Actinomyces asteroides.— Isolated by Eppinger in 1891 from a brain abscess in a glass- 

 grinder. Consists of threads showing true and false branching ; threads may be long, 

 or short and segmented ; tiny rod forms also seen. In the body it forms long, granular, 

 interlacing filaments with no ray or club formation. Gram-positive. Acid-fast, though 

 not so strongly as the tubercle bacillus. Aerobic ; no growth anaerobically. Destroyed 

 by heat at 70° C. in 5 minutes. On agar — at first whitish, later ochre-coloured, umbonate 

 colonies, having a raised, dry, wrinkled, opaque centre and a moist glistening more trans- 

 lucent peripheiy with a mycehoid edge ; whole colony star-shaped — hence the name 

 asteroides — may be a central depressed crater ; later, colour deepens to orange, and the 

 wrinkhng of the surface becomes more marked. Agar slope — raised ochre growth with 

 a mealy surface and entire edge. Gelatin — very slow growth without liquefaction. Potato 

 ^red raised growth with a granular, and later wrinkled, surface ; a chalk-white bloom may 

 develop due to a velvet-like upgrowth of fine filaments into the air. These upHfted fila- 

 ment s have terminal chains of coccoid bodies or spores, which, when transferred to broth, 

 sprout and give rise to long filaments or star-like clusters (MacCallum 1902). Broth — white 

 surface pellicle, which falls to the bottom, and is renewed several times ; no turbidity. 

 After subcutaneous, intraperitoneal, or intravenous injection, rabbits and guinea-pigs die 

 in 5 days to 4 weeks. Post mortem, the viscera, especially lungs, liver, and spleen, are 

 studded with small white nodules. Abscesses may develop in the muscles, kidneys, and 

 other organs ; these abscesses contain branching test-tube brush forms with laterally 

 radiating clubs. An organism called Actinomyces variabilis with similar pathogenicity 

 but different cultural reactions to Eppinger's strain was isolated by Cohn (1913) from 

 the bladder of a man with pyuria. 



Actinomyces gypsoides. — Isolated by Henrici and Gardner (1921) from the sputum 

 of a woman. Acid-fast branching filaments were found in the sputum, sometimes in 

 mycelial form. Agar slope — thin greyish veil, soon becoming thick, opaque, and chalky- 

 white ; surface dry and wrinkled ; growth finely adherent to the medium and very brittle. 

 Potato — growth similar to that on agar. Gelatin stab — surface growth only ; liquefaction 

 stratiform and complete in a week. Broth — small white flakes coalescing to form a thick, 

 wrinkled, snow-white surface pellicle extending up sides of tube. Litmus milk — yellowish 

 surface pellicle ; milk is turned alkaUne and curdled ; litmus reduced ; later digestion. 

 Media containing peptone are darkened (tyrosinase). Growth improved by dextrose, 

 maltose, and glycerol. No carbohydrates fermented. Intravenous injection into rabbits 

 is fatal in 2 days ; post mortem, minute abscesses in viscera, especially kidneys, which 

 are studded with yellowish-white nodules. Intraperitoneal injection into guinea-pigs is 

 fatal in 4 to 6 days ; post mortem, small tubercle-like nodules over peritoneum ; omentum 

 shrunken and studded with nodules. 



An acid- fast strain described by Birt and Leishman (1902) gave a snow-white growth 

 on soUd media, peptonized millv, but did not liquefy gelatin. Another acid-fast strain 

 described by Berestnew (see Feistmantel 1902) gave a grey to whitish growth, liquefied 

 gelatin, but was non-pathogenic to laboratory animals. More recently, Goldsworthy 

 (1937) has given a good description of an acid-fast strain isolated from a patient with 

 pulmonary actinomycosis. 



C. Other Facultative aerobic Types. 



Described by Naeslund (1925), who isolated organisms of two different types from the 

 human mouth. 



