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MANUAL OF DETERMINATIVE BACTERIOLOGY 



17. Bacteroides ovatus Eggerth and 

 Gagnon. (Eggerth and Gagnon, Jour. 

 Bact., 25, 1933, 405; Pasteurella ovata 

 Pr^vot, Ann. Inst. Past., 60, 1938, 292.) 

 From Latin ovatus, egg-shaped. 



Small oval rods: 0.5 to 1.0 by 1.0 to 

 2.0 microns, occurring singly. Stains 

 solidly. Non -motile. Gram-negative. 



Gelatin: Liquefied in 4 days. 



Blood agar colonies: Soft, grayish, 

 elevated colonies, 1.0 to 1.5 mm in diam- 

 eter. 



Broth: Diffuse, heavy growth. 



Indole is formed. 



Hydrogen sulfide is produced. 



Milk : Acidified and coagulated in 4 

 days. 



Nitrites not produced from nitrates. 



Peptone : No gas. 



Acid and a small amount of gas from 

 esculin, amygdalin, cellobiose, dextrin, 

 fructose, galactose, glucose, glj^cogen, 

 inulin, lactose, maltose, mannose, rafR- 

 nose, rhamnose, starch, sucrose and 

 xylose. No acid or gas from arabinose, 

 glycerol, mannitol, melezitose, salicin, 

 sorbitol or trehalose. 



Non-pathogenic for white mice and 

 rabbits. 



Anaerobic. 



Source : One strain isolated from 

 human feces. 



Habitat : Probably intestinal canal of 

 mammals. 



18. Bacteroides uniformis Eggerth and 

 Gagnon. (Eggerth and Gagnon, Jour. 

 Bact., 25, 1933, 400; Ristella uniformis 

 Prdvot, Ann. Inst. Past., 60, 1938, 291.) 

 From Latin uniformis, of a single form. 



Small rods: 0.8 to 1.5 microns long, 

 occurring singly, with rounded ends. 

 Stain heavier at poles and around periph- 

 ery. Non-motile. Gram-negative. 



Gelatin : Liquefied by two strains in 

 15 to 40 days. Six strains did not liquef}^ 



Blood agar colonies: Transparent, soft, 

 elevated, 0.5 to 0.75 mm in diameter. 



Broth: Diffuse growth. 



Indole formed. 



Hydrogen sulfide produced slowly or 

 not at all. 



Milk : Acidified and coagulated in 8 to 

 12 days. 



Nitrites not produced from nitrates. 



Peptone : No gas. 



Acid but no gas from esculin, amyg- 

 dalin, arabinose, cellobiose, dextrin, fruc- 

 tose, galactose, glucose, glycogen, inulin, 

 lactose, maltose, mannose, melezitose, 

 raffinose, salicin, starch, sucrose, treha- 

 lose and xylose. No acid or gas from 

 glycerol, mannitol, rhamnose, sorbitol, 

 dulcitol, erythritol or inositol. 



Non-pathogenic for white mice and 

 rabbits. 



Anaerobic. 



Distinctive characters: Forms indole. 

 Resembles Bacteroides vulgatus. 



Source: Eight strains isolated from 

 human feces. 



Habitat : Probably intestinal canal of 

 mammals. 



19. Bacteroides thetaiotaomicron 



(Distaso) Castellani and Chalmers. 

 {Bacillus thetaiotaomicron Distaso, Cent, 

 f. Bakt., I Abt., Grig., 62, 1912, 444; 

 Castellani and Chalmers, Man. Trop. 

 Med., 3rd ed., 1919, 960; Spherocillus 

 thetaiotaomicron Pr^vot, Ann. Inst. Past., 

 60, 1938, 300.) The combination theta, 

 iota and omicron is used because the 

 pleomorphic rods have the shape of these 

 Greek letters. 



Description taken from Distaso {loc. 

 cit.). More complete description will 

 be found in Eggerth and Gagnon (Jour. 

 Bact., 25, 1933, 399). 



Short, plump to oval rods. Stain 

 solidly or only at poles. Sometimes with 

 bar causing organism to resemble Greek 

 letter theta. Motile (Distaso). Non- 

 motile (Eggerth and Gagnon). Gram- 

 negative. 



Gelatin: No liquefaction. 



Glucose agar colonies: Large, trans- 

 parent, entire. Sometimes form gas 

 bubbles. 



Broth: Turbid. 



