100 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



geniculatus, p.p. of geniculo, knotted, 

 jointed. 



Medium-sized rods, occurring singly, 

 in pairs and chains, motile, possessing 

 polar flagella. Gram-negative. 



Gelatin colonies: Circular, whitish, 

 translucent. Deep colonies yellowish. 



Gelatin stab : Infundibuliform liquefac- 

 tion. Sediment light pink. 



Agar slant : Grayish, glistening, trans- 

 lucent, limited, becoming brownish-graj'. 



Broth : Turbid, with slight gray pellicle 

 and sediment. 



Litmus milk : Alkaline ; reduction of 

 litmus; slight coagulation. 



Potato: Thin, brownish, moist, glis- 

 tening, viscid. 



Indole not formed. 



Nitrites not produced from nitrates. 



Aerobic, facultative. 



Optimum temperature 20° to 25°C. 



Habitat : Water. 



32. Pseudomonas fragi (Eichholz) 

 Huss emend. Hussong, Long and Hammer. 

 (Bacterium fragi Eichholz, Cent. f. 

 Bakt., II Abt., 9, 1902, 425; Huss, Cent, 

 f. Bakt., II Abt., 19, 1907, 661; Hussong, 

 Long and Hammer, Iowa Agr. Exp. Sta. 

 Res. Bull. 225, 1937, 122; also see Long 

 and Hammer, Jour. Dairy Sci., 20, 1937, 

 448.) From Latin /ra^um,. strawberry. 



Description from Hussong, Long and 

 Hammer, loc. cit. 



Rods: 0.5 to 1.0 by 0.75 to 4.0 microns, 

 occurring singly, in pairs and in chains. 

 Motile with a polar flagellura. Gram- 

 negative. 



Gelatin: Crateriform to stratiform 

 liquefaction in 3 to 4 days. 



Agar colonies: Convex, glistening, gen- 

 erally butyrous, occasionally viscid. 

 Rough, smooth and intermediate forms 

 are recognized in the description quoted. 

 The rough forms are less proteolytic, and 

 less active in the hydrolysis of fats. 



Agar slant : Growth abundant, spread- 

 ing, raised, white, shiny, generally 

 butyrous. Sweet ester-like odor resem- 

 bling that of the flower of the May apple. 



Broth : Turbidity and sediment with a 

 thin pellicle. 



Litmus milk : Acid ring followed by 

 acid coagulum at surface. Complete 

 coagulation in 2 to 3 weeks, some diges- 

 tion. Characteristic May apple or straw- 

 berry odor. 



Potato : Growth echiuulate to arbores- 

 cent, raised, glistening, white, becoming 

 brownish. 



Indole not produced. 



Nitrites not produced from nitrates. 



Ammonia produced from peptone. 



Hydrogen sulfide not produced. 



Acid from glucose and galactose, 

 sometimes arabinose. No acid from 

 glycerol, inulin, lactose, fructose, mal- 

 tose, mannitol, raflfinose, salicin and 

 sucrose. 



No acetylmethylcarbinol produced. 



Fat is generally hydrolyzed. 



Aerobic. 



Grows from 10° to 30°C. No growth at 

 37°C. Very sensitive to heat. 



Source: Isolated from milk and other 

 dairy products, dairy utensils, water, etc. 



Habitat : Soil and water. Widely dis- 

 tributed (Morrison and Hammer, Jour. 

 Dairy Sci., U, 1941, 9). 



Hussong (Thesis, Iowa State College, 

 1932) regards Bacterium fragi Eichholz 

 (loc. cit.) as the R type, Pseudomonas 

 fragariae I Gruber (Cent. f. Bakt., II 

 .\bt., 9, 1902, 705) as the O form, and 

 Pseudomonas fragariae II Gruber (Cent, 

 f. Bakt., II Abt., 14, 1905, 122) as the S 

 form of the same organism. He makes no 

 mention of Pseudomonas fragaroidea 

 Huss (loc. cit.) which from its description 

 would belong to the smooth type. A 

 brief characterization of each of these 

 organisms follows : (1 ) Bacterium fragi 

 came from milk as drawn from an indi- 

 vidual cow; it does not liquefy gelatin, 

 exhibits no fluorescence, is strongly alka- 

 line in litmus milk, and does not grow 

 at 37°C, (2) Pseudomonas fragariae I 

 came from fodder beets; it does not 

 liquefy gelatin, has weak blue-greenish 

 fluorescence, is weakly alkaline in milk, 

 and grows at 37°C, (3) Pseudomonas 

 fragariae II came from pasteurized milk ; 

 it liquefies gelatin, coagulates milk, and 

 does not grow at 37''C, (4) Pseudomonas 



