FAMILY ENTEROBACTERIACEAE 



449 



Epstein and Vaughn, Amer. Jour. Pub. 

 Health, 2J^, 1934, 505; Tittsler and Sand- 

 holzer, Amer. Jour. Pub. Health, 27, 

 1937, 1240). 



Trimethyleneglycol produced from 

 glycerol by anaerobic fermentation 

 (Braak, loc. cit., 146; Werkman and 

 Gillen, loc. cit., 167). 



Acid and gas from glucose, fructose, 

 galactose, arabinose, xylose, rafRnose, 

 lactose, maltose, mannose, rhamnose, 

 trehalose, glycerol, mannitol and sorbitol. 

 Sucrose, salicin, dulcitol, adonitol and 

 inositol may or may not be fermented. 

 Cellobiose usually fermented while a- 

 methyl-glucoside may or may not be 

 fermented (Tittsler and Sandholzer, loc. 

 cit.; Carpenter and Fulton, loc. cit.). 

 No acid or gas from amygdalin, dextrin, 

 erythritol, glycogen, inulin or melezitose. 



Aerobic, facultative. 



Growth requirements : Good growth on 

 ordinary laboratory media. Optimum 

 growth temperature 30° to 37°C. Gas 

 not produced in Eijkman test when car- 

 ried out at 45° to 46°C (Levine, Epstein 

 and Vaughn, loc. cit.). No gas at 44°C 

 (Wilson, Med. Res. Council, London, 

 Special Rept. Ser. 206, 1935, 165). 



Habitat : Normally found in soil and 

 water and to a varying degree in the 

 intestinal canal of man and animals. 

 Widely distributed in nature. 



3. Escherichia intermedium (Werkman 

 and Gillen) Vaughn and Levine. {Citro- 

 bacter intermedium Werkman and Gillen, 

 Jour. Bact., 23, 1932, 178; Vaughn and 

 Levine, Jour. Bact., U, 1942, 498.) 



Citrohacter glycologenes W^erkman and 

 Gillen {loc. cit.) is also regarded as a 

 synonym of Escherichia intermedium. 

 Vaughn and Levine (loc. cit.) give a 

 new description of Escherichia inter- 

 medium based on a study of 27 cultures. 



Rods: Short rods with rounded ends. 

 Occurring singly, in pairs and short chains 

 in young nutrient agar or broth cultures. 

 Actively motile with peritrichous flagella 

 or non-motile. Gram -negative. 



Gelatin stab : No liquefaction after 60 

 days at 20°C. 



Agar slant : Smooth to wrinkled surface, 

 grayish-white, abundant, raised and 

 butyrous growth. 



Nutrient broth : Turbid with slight 

 ring at surface. 



Litmus milk : Acid, sometimes coagula- 

 tion and reduction, no proteolysis. 



Potato: Growth abundant, white to 

 ivory color. 



Levine's eosine -methylene blue agar: 

 Well-isolated colonies vary from 1 to 4 

 mm in size. No confluence of neighbor- 

 ing colonies. Colonies are slightly to 

 moderately raised with surfaces varying 

 from flat to convex and usually smooth 

 and glistening but sometimes dull, rough 

 and granular. 



By transmitted light two types of 

 colonies have been observed : (1 ) Colonies 

 having almost the same appearance 

 throughout but with a distinctly lighter 

 center, the color being similar to the 

 medium. (2) Colonies having a dark 

 brownish central area which diifuses out 

 to a lighter margin. 



By reflected light three types of col- 

 onies have been observed: (1) Dark, 

 button-like, concentrically ringed col- 

 onies possessing a strong, greenish- 

 metallic sheen so characteristic for 

 Escherichia coli. (2) Colonies with 

 dark, purplish, wine-colored centers 

 surrounded by a light pink zone. Some 

 colonies are concentrically ringed. (3) 

 Pink colonies with no suggestion of sheen 

 but sometimes concentrically ringed. 



Indole may or may not be formed. 



Nitrites produced from nitrates. 



Fermentation of glucose : The end prod- 

 ucts characteristic for the genus Escheri- 

 chia are formed. Carbon dioxide and 

 hydrogen gases are formed in approxi- 

 mately equimolar proportions (gas ratio 

 1:1) besides significant quantities of 

 ethyl alcohol, and acetic, lactic and 

 succinic acids with only traces of formic 

 acid. Acetylmethylcarbinol and 2-3 



