FAMILY VI. BACTEROIDACEAE 



427 



Anaerobic. 



Non-pathogenic for white mice or rabbits. 



Source : Two strains were isolated from 

 human feces. 



Habitat: Probably the intestinal canals 

 of mammals. 



5. Bacteroides insolitvis Eggerth and 

 Gagnon, 1933. (Eggerth and Gagnon, Jour. 

 Bact., 25, 1933, 408; Ristella insolita Prevot, 

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



in.so.li'ta. L. adj. insolitus unusual. 



Short, thick rods, 1 to 2 microns long, 

 often occurring as slender, curved cells, 

 2 to 3 microns long. Non-motile. Gram- 

 negative. 



Gelatin: No liquefaction in 45 days. 



Blood agar colonies: Minute, transparent. 



Broth: Heavy, diffuse growth. 



Milk: Acidified and coagulated in 30 to 

 35 days. 



Indole is produced. 



Hydrogen sulfide is produced. 



Acid but no gas from fructose, galactose, 

 glucose, glycerol, lactose, maltose and 

 niannose. No acid or gas from esculin, 

 amygdalin, arabinose, cellobiose, dextrin, 

 glycogen, inulin, mannitol, melezitose, 

 raffinose, rhamnose, salicin, sorbitol, starch, 

 sucrose, trehalose or xylose. 



Nitrites not produced from nitrates. 



Anaerobic. 



Non-pathogenic for white mice or rabbits. 



Distinctive characters: Brom cresol 

 purple and phenol red are rapidly decolor- 

 ized in a meat infusion broth. A small 

 amount of gas is produced from peptone. 



Source: One strain was isolated from hu- 

 man feces. 



Habitat: Probably the intestinal canals 

 of mammals. 



6. Bacteroides thetaiotaomicron (Dis- 

 taso, 1912) Kelly, comb. nov. {Bacillus 

 thetaiotaomicron Distaso, Cent. f. Bakt., I 

 Abt., Orig., 62, 1912, 444; Bacteroides tethai- 

 otaomicron (sic) Castellani and Chalmers, 

 Man. Trop. Med., 3rd ed., 1919, 960;/SpAae/'o- 

 cillus thetaiotaomicron Prevot, Ann. Inst. 

 Past., 60, 1938, 300.) 



the.ta.i.o.ta.o'mi.cron. M.L. noun the- 

 taiotaomicron a combination of the Greek 

 letters theta, iota and omicron, so used 



because the pleomorphic rods of this species 

 have the shapes of these letters. 



Description taken from Distaso (op. cit., 

 1912, 444) ; a more complete description will 

 be found in Eggerth and Gagnon (Jour. 

 Bact., 25, 1933, 399). 



Short, plump to elliptical rods which 

 sometimes have a bar across them, thus 

 causing the organism to resemble the Greek 

 letter theta. Motile (Distaso). Non-motile 

 (Eggerth and Gagnon). Stain solidly or only 

 at the poles. Gram-negative. 



Gelatin: No liquefaction. 



Glucose agar colonies : Large, transparent, 

 entire; sometimes gas bubbles are produced. 



Broth: Turbid. 



Egg albumen broth: Albumen not at- 

 tacked. 



Litmus milk: Acid, coagulated. Curd 

 shrinks with expulsion of turbid whey. 



Indole is produced. 



Hydrogen sulfide produced (Eggerth and 

 Gagnon) . 



Acid and gas from esculin, amygdalin, 

 arabinose, fructose, inulin, lactose, cello- 

 biose, dextrin, galactose, glucose, glycogen, 

 maltose, mannose, melezitose, raffinose, 

 rhamnose, salicin, starch, sucrose, trehalose 

 and xylose. Four strains fail to produce gas 

 from any sugar. No acid or gas from glyc- 

 erol, mannitol or sorbitol (Eggerth and 

 Gagnon) . 



Nitrate reduction not recorded (Distaso). 

 Nitrites not produced from nitrates (Eg- 

 gerth and Gagnon). 



Peptone: No gas (Eggerth and Gagnon). 



Anaerobic. 



Distinctive characters: Resembles Bac- 

 teroides variabilis but is not encapsulated, 

 does not liquefy gelatin, usually produces 

 gas from sugars and ferments melezitose and 

 trehalose. Differs from Bacteroides uniformis 

 in morphology, in producing gas from sugars 

 and in fermenting rhamnose (Eggerth and 

 Gagnon) . 



Source: Isolated frequently from human 

 feces. 



Habitat: Intestinal canals of mammals 

 (common). 



7. Bacteroides trichoides (Potez and 

 Compagnon, 1922) Hauduroy et al., 1937. 

 {Bacillus trichoides Potez and Compagnon, 



