THE GENUS ACTINOMYCES 17 



followed rapidly by a fairly voluminous pale israeli Pinoy, 1913; Nocardia israeli Castel- 



pink, homogenous precipitate. lani and Chalmers, L913; Brevistreptothrix 



Thioglycollate medium: Growth either israeli Lignieres, L924; Proactinomyces israeli 



diffuse, netlike, or dispersed and granular. Jensen, L931; Cor ynebacterium israeli Lentze, 



Gelatin: Liquefied. L938; Actinomyces israeli var. indo-sinensis 



Milk: Coagulated in 24 to 48 hours and Reynes, 1947. 



peptonized in :! weeks. Morphology: Large, club-shaped forms 



Blood: All strains hemolyze human blood are seen in morbid tissues. Substrate myce- 



iiii solid media bul do not form a soluble lium consists of rapidly septating and spor- 



hemolysin. ulating hyphae. The branches may extend 



Sugar utilization: Galactose, fructose, and into the medium in long filaments or may 



glycerol vigorous; inulin, maltose, mannitol, exhibit fragmentation and characteristic an- 



saccharose, starch, dulcitol, and lactose gular branching. Hyphae occasionally sep- 



soniewhat less readily; xylose and arabinose tate, hut no definite spores are formed. 



not at all. Colonies exhibit a considerable degree of 



Reduction: Some strains form a little hy- polymorphism, but no stable variants have 



drogen sulfide. Sulfites and sulfates are not been established. Colonies are tougher in 



reduced. Nitrates reduced to nitrites and in texture than those of .1. bovis. Old colonies 



some cases to ammonia. Safranin, phenosaf- warted in appearance (Fig. 4). 



ranin, or neutral red not reduced. Most Gelatin : Growth scant, flaky . No liquefac- 



Strains decolorize methylene blue in 4 to 24 tion. 



hours; some do not . Liquid media: Growth in form of white 



Temperature: Optimum 37°C. Heating to compad colonies or granular sediment. Me- 



.">() lit) (' for L5 minutes injurious. dium shows no turbidity, usually remaining 



Remarks: All strains catalase-positive. All clear. No gas and no odor, 

 produce ethyl alcohol, aldehyde, acetone. Pigments: No soluble or insoluble pig- 

 ammonia. A faint indol reaction is found in ments. 



alkaline distillate. The presence of volatile Egg media: No proteolytic action. 



acids, tartaric acid, and lactic acid has been Milk: Becomes acid, but usually does 



demonstrated, but not succinic acid. Pro- not clot. No peptonization. Frequently no 



pionic acid and formic acid in ratios of from growth. 



."> to 1 up to 20 to 1 for the six strains ex- Starch : Slight hydrolysis, 



amined. Oxygen requirement: Anaerobic. 



Habitat : ( i round water. Nitrate reduction: ( ienerally negative. 



Remarks: Kalakoutskii (1960) found an- Sugar utilization : Greater ability to utilize 



aerobic actinomycetes in natural waters and sugars than .1. bovis. Acid but no gas from 



in the air of apartments occupied by man, glucose, galactose, lactose, fructose, maltose, 



but not in the soil. raffinose, sucrose; no acid from inulin. 



(i. Actinomyces israelii (Kruse) Lachner- Hemolysis: Slight to marked. 



Sandoval, 1898 (Wolff, M. and Israel, J. Serological reactions: Pack oi serological 



Arch, pathol. Anat. 126: 11, 1891). affinity with A. bovis. 



Synonyms: Streptothrix israeli Kruse, Temperature: Optimum 37°C. Destroyed 



1896; Discomyces israeli Gedoelst, 1902; at 55-60°C in 30 minutes. 



Actinomyces bovis Wright, 1905; Discomy- Habitat: Dental caries, tonsils, and natu- 



ces l><>ris Brumpt, L906; Actinobacterium ral cavities of man and animals. Chief etio- 

 israeli Sampietro, 1908; Cohnistreptothrix logical agent of human actinomycosis, de- 



