190 



ORDER I. PSEUDOMONADALES 



1. Not proven to be pathogenic for fish and amphibians. 



1. Aeromonas liquefaciens. 



2. Generally regarded as the cause of an infectious edema of carp and other fish. 



2. Aeromonas punctata. 

 B. Originally isolated from a septicemia in frogs (red leg). 



3. Aeromonas hydrophila. 

 II. Non-motile. Pathogenic for fish, particularly Salmonidae. 



4. Aeromonas salmonicida. 



1. Aeromonas liquefaciens (Beijerinck, 

 1900) Kluyver and van Niel, 1936. {Aero- 

 bacter liquefaciens Beijerinck, Cent. f. Bakt., 

 II Abt., 6, 1900, 199; Kluyver and van Niel, 

 Zent. f. Bakt., II Abt., 94, 1936, 399.) 



li.que.fa'ci.ens. L. v. liquefacio to 

 liquefy; L. part. adj. liquefaciens liquefying. 



Description taken from Beijerinck (op. 

 cit., 6, 1900, 199) and from E. M. Miles and 

 A. A. Miles (Jour. Gen. Microbiol., 5, 1951, 

 299). 



Rods, 0.4 to 0.8 by 1.5 to 3.0 microns, 

 with parallel sides and rounded ends. Fila- 

 ments common in "rough" colony forms. 

 Motile by means of a single polar flagellum 

 about 5 to 6 microns long. Gram-negative. 



Gelatin stab: Liquefaction marked and 

 commonly saccate, good growth. 



Horse blood agar colonies: 2 to 3 mm in 

 diameter, round, entire, raised, smooth, 

 moist, opaque, semi-translucent, grayish 

 white, forming a dirty brown-yellow colora- 

 tion after 3 to 5 days at room temperature ; 

 non-hemolytic. 



Broth: Growth abundant, turbid, with a 

 moderate, readily disintegrable sediment 

 and delicate pellicle. 



Loeffler's serum: Growth abundant, but 

 no digestion. 



Litmus milk: Acid; coagulated; digested. 



Potato: Growth abundant, moist and 

 glistening, light brown. 



Indole is produced. 



Nitrites but not ammonia produced from 

 nitrates (Beijerinck); ammonia produced, 

 presumably from peptones (Miles and 

 Miles) . 



Methyl red test negative. 



Citric acid and salts of citric acid may be 

 utilized as sole sources of carbon. 



Ammonium sulfate, uric acid and aspara- 

 gine may be utilized as sources of nitrogen. 



Catalase produced. 



Hydrogen sulfide produced. 



Urea not attacked. 



Methylene blue reduced. 



Starch hydrolyzed (Miles and Miles) ; 

 starch not hydrolyzed (Beijerinck). 



Acid and gas from glucose, galactose, 

 fructose, mannose, maltose, sucrose, man- 

 nitol, glycerol and starch. Acid from lactose, 

 raffinose, inositol and sorbitol. Slight acid 

 from salicin at 22° C. but none at 37° C. 

 Glucose fermented with the production of 

 2,3-butanediol. Arabinose, rhamnose and 

 dulcitol not attacked. 



Aerobic, facultative. 



Temperature relations: Optimum, 37° C; 

 good growth on ordinary laboratory media 

 at 20° C. 



Produces a characteristic black-rot in 

 hen eggs. 



Pathogenic to mice, also to frogs, causing 

 a fatal bacteriemia. 



Source: Found rarely in canal mud, 

 generally in certain marshes and swamps. 



Habitat relationships uncertain. Those 

 that believe this organism to be identical 

 with Aeromonas punctata would associate it 

 with a disease of carp, eels and other fishes. 



2. Aeromonas punctata (Zimmermann, 

 1890, emend. Lehmann and Neumann, 1896) 

 Snieszko, comb. nov. (Bacillus punctatus 

 Zimmermann, Bakt. unserer Trink- und 

 Nutzwasser, Chemnitz, 1, 1890, 38; Bac- 

 terium punctatum Lehmann and Neumann, 

 Bakt. Diag., 1 Aufl., 2, 1896, 238; Pseudo- 

 monas punctata Chester, Man. Determ. 

 Bact., 1901, 147; also see Schaperclaus, 

 Ztschr. f. Fischerei, 28, 1930, 289.) 



punc.ta'ta. L. noun punctum a point, a 

 small hole; M.L. adj. punctata full of points. 



Rods, 0.7 by 1.0 to 1.5 microns, occurring 

 singly, in pairs and in chains. Motile with 

 a single polar flagellum. Gram-negative. 



Gelatin colonies: Small, circular, gray, 

 erose to filamentous, punctiform. 



