Litmus milk: Slowly acidified; slimy, viscid. Sometimes coagulated and reduced. No caseolysis. Potato: No visible growth. Indole not produced. Hydrogen sulfide is produced. Acid but no gas from glucose, fructose, xylose, lactose, galactose, maltose, sucrose, mannitol and raffinose. Dextrin usually fermented. No action on rhamnose, dulcitol, sorbitol or inositol. Usually no action on salicin, adonitol or arabinose. Acetylmethylcarbinol not produced. Uric and citric acids not utilized. Nitrites produced from nitrates. Trimethylamine not produced from tri- methylamine oxide (Wood et al., Jour. Bact., 46, 1943, 100). Optimum temperature, 37° C. Does not grow at 45.5° C. (Stuart et al., Jour. Bact., 46, 1943, 105). Aerobic, facultatively anaerobic. Non-hemolytic. Not pathogenic for small experimental animals. Produces abscesses and joint -ill when infected subcutaneously into horses. Serologically heterogeneous (Edwards) ; related serologically to Actinobacillus Ugnieresii Brumpt and to A. mallei Thomp- son (Haupt, op. cit., 1934, 524). Source: Isolated from cases of joint-ill in foals. Habitat : Generally a harmless inhabitant of the intestinal canal of solipeds; causes joint-ill and nephritis purulenta chiefly in foals 1 to 4 days old, sometimes in adoles- cent solipeds. 3. Actinobacillus actinomycetenico- mitans Topley and Wilson, 1936. {Bac- terium actinomycetem comitans Klinger, Cent. f. Bakt., I Abt., Orig., 62, 1912, 198; Bacterium comitans Lieske, Morph. u. Biol, d. Strahlenpilze, 1921, 233; Actinobacillus actinomycetem comitans Topley and Wilson, Princip. of Bact. and Inmaun., 1st ed., 1, 1931, 253 and 256; Topley and Wilson, ibid., 2nd ed., 1936, 279.) ac . ti . no . my . ce . tem. co'mi . tans. Gr. noun actis, actinis a ray; Gr. noun myces, myce- tis a fungus; M.L. noun actinomyces ray fungus; L. part. adj. comitans accompa- nying; M.L. part. adj. actinomycetemcomi- tans accompanying an actinomycete. Description taken from Topley and Wil- son {loc. cit.), Colebrook (Brit. Jour. Exp. Path., 1, 1920, 197) and Bayne-Jones (Jour. Bact., 10, 1925, 572). Cocco-bacilli, occurring as rods, 1.0 to 1.5 microns long, or as cocci, 0.6 to 0.8 micron in diameter, in densely packed masses. Non-motile. Gram-negative. Generally will grow on nutrient media under aerobic as well as anaerobic condi- tions; increased CO2 tension accelerates growth (Holm, Riassunti delle Comunica- zioni, VI Congresso Internaz. di Micro- biologia, Roma, 1, 1953, 407; also see Acta Path, et Microbiol. Scand., 34, 1954, 235; abst. of the latter paper in Biol. Abst., 29, 1955, No. 6185). Gelatin: No liquefaction. Agar colonies: Small, transparent, hemi- spherical, tough, adherent. Glucose agar: Growth thin, dry, granular, hard, slightly yellow, adherent. Liquid gelatin or broth: At 37° C., numer- ous, isolated, translucent granules, 0.5 to 1.0 nma in diameter; adherent granules are formed along the walls of the tube. In a few days they fuse into a grayish white mass, fornndng a ring around the tube and a pel- licle over the surface. Later the granules become opaque and grayish white. Glucose broth: Turbid. Yellowish flakes. Milk: No growth. Potato: No growth. Acid but no gas from glucose and lactose. Aerobic, facultatively anaerobic. No growth at 22° C. Not pathogenic for laboratory animals. Toxic to rabbits on injection, but a true infection is not set up. Distinctive character: Manner of growth in liquid gelatin. Relationship to other species: Compara- tive investigations may show this organism to be identical wuth Actinobacillus Ugniere- sii Brumpt. Source: Originally isolated from lesions of actinomycosis; also found in a jaw infec- tion in a young woman (Thj0tta and Sydnes, Acta Path, et Microbiol. Scand., 28, 1951, 27; abst. in Biol. Abst., 25, 1951, No. 28469)
