384 ACTINOMYCES 



periphery ; growth extends to bottom of tube. Shghtly raised surface growth 

 about 3 mm. in diameter. Slight liquefaction after 6 weeks. 



Broth. — 7 days at 37° C. Poor growth. Deposit of little greyish-white puff-balls, looking 

 like colonies of moulds, and having a dense centre and a lighter periphery ; often 

 cohering in groups of two or three. No turbidity ; no surface growth ; no odour. 

 Later a white efflorescent surface growth may appear. 



Loeffler's Serum. — 7 days at 37° C. Poor growth of isolated colonies. 21 days, moderate 

 growth of heaped-up nodular colonies. No liquefaction. 



Glucose Agar Slope. — 7 days at 37° C. Discrete colonies, raised, heaped-up, with worm- 

 cast surface, moist and ghstening. 



Glycerol Agar Slope. — 12 days at 37° C. Luxuriant, raised, confluent, greyish-white worm- 

 cast growth, very tough, adherent to medium, and difficult to emulsify. 



Glycerol Egg. — 7 days at 37° C. Mostly confluent growth of rounded, dome-like colonies 

 with dull nodular surface. Very tough, adherent to medium, and difficult to 

 emulsify. No liquefaction. 



Potato. — 7 days at 37° C. Discrete, heaped-up, nodular, yellowish-brown colonies. 18 

 days, heaped-up dry, chalky-white and greyish-brown, worm-cast colonies. Later 

 may take on a rose-red colour. 



MacConkey.—'No growth on solid or liquid media. 



Resistance.- — Destroyed by moist heat at 60° C. in 5 minutes. 



Metabolism.- — Aerobic ; very shght growth on glycerol agar anaerobically. Optimum 

 temperature 37° C. ; grows at 20° C. Forms sometimes a rose-red pigment on 

 potato. Growth improved by glycerol and glucose. 



Biochemical. — Ferments no sugars. L.M. turned slightly alkaline ; may be peptonized. 

 Indole — ; M.R. — ; V.P. — ; Nitrate reduction -{- ; HjS — ; NH3 si. -f ; Catalase 

 V. si. -j- ; M.B. reduction — . 



Pathogenicity. — Subcutaneous inoculation into rabbits, guinea-pigs, mice, and cats causes 

 a local nodule, which increases in size for a month and then retrogresses. Respon- 

 sible for pale or ochroid variety of Madura disease in man. 



Actinomyces graminis Bostroem 



Isolation. — Isolated by Bostroem in 1891 from human actinomycosis. Subsequently 

 isolated by numerous workers from different lesions in man and other animals. 



Habitat. — Saprophyte living on grains and grasses. Often gains access to mouth and 

 respiratory passages of man and other animals. 



Morphology. — Agar 24 hours at 37° C. Long filaments, 0-6 /n wide, showing true and 

 false branching ; long and short rods, and coccoid bodies. Sides parallel, ends 

 rounded or tapering. Filaments are straight, wavy, or spirillar, and may or may 

 not be segmented. Arranged in small loose groups, or in a mycehum. In broth 

 ray forms are frequent, with compact centre and radiating filaments. Staining 

 of rods and filaments is often irregular. Non-motile. Gram-positive. Non- 

 acid-fast. 



Agar Plate. — 24 hours at 37° C. Round, greyish-white, low convex, dull, opaque 

 colonies with finely granular surface and erose edge. 7 days, rounded, up to 3 mm. 

 in diameter, umbonate, granular colonies, with raised, opaque, primrose-yellow, 

 radially striated centre, and effuse, greyish, ground-glass periphery. Surface 

 granular, edge feathery or rhizoid. Generally tough and adherent to agar, and 

 difficult to emulsify. Colonies may be folded on surface and coral-like, or they 

 may be undifferentiated with a nodular surface and lobate edge. Colour may 

 be chalky-white, yellow or brown. 



Agar Slope. — 24 hours at 37° C. Abundant, slightly raised, greyish-white, faintly trans- 

 lucent or opaque growth with dull, finely granular or mealy surface and entire or 

 erose edge. 7 days, surface is whitish and moderately granular ; growth may 

 be heaped-up in places. 



