232 



ORDER I. PSEUDOMONADALES 



possessing a single polar flagellum. Gram- 

 negative. 



Gelatin colonies: Small, yellowish white. 



Gelatin stab: Rapid, napiform liquefac- 

 tion. 



Agar colonies: Circular, whitish brown, 

 moist, glistening, translucent, slightlj^ 

 raised, entire. 



Agar slant: Brownish gray, moist, glisten- 

 ing. 



McConkey's medium: Good growth, 

 colonies colorless when young, soon pinkish, 

 medium becomes darker red. 



Broth: Slightly turbid, with fragile, 

 wrinkled pellicle and flocculent precipitate. 



Peptone water: Characteristic rapid 

 growth, chiefly at surface, where, after 6 

 to 9 hours, a delicate membrane is formed; 

 little turbidity, deposit apparently derived 

 from pellicle (Topley and Wilson, Princip. 

 Bact. and Immun., 2nd ed., 1936, 388). 

 Readily isolated from the surface film of 

 0.1 per cent peptone water. 



Litmus milk: Alkaline at the top and 

 slightly acid at bottom; generally not 

 coagulated; peptonized; reduced. 



Potato: Dirty white to yellowish, moist, 

 glistening, spreading growth. 



Blood serum: Abundant growth, some- 

 times slow liquefaction. 



Blood agar: The blood pigment is di- 

 gested forming a greenish zone around 

 colonies; a true soluble hemolysin is not 

 formed (the El Tor vibrio also digests 

 blood pigment but in addition produces a 

 soluble hemolysin; otherwise it is said to 

 be indistinguishable from the typical 

 cholera vibrio) . 



Indole produced. 



Cholera-red reaction, which depends on 

 production of indole and reduction of 

 nitrates, is positive. 



Hydrogen sulfide produced. 



Acid but no gas from glucose, fructose, 

 galactose, maltose, sucrose and mannitol. 

 Slowly from glycerol. Does not attack 

 lactose, inulin or dulcitol. 



Group I of Heiberg (Classification of 

 Vibrio cholerae and Cholera-like Vibrios. 

 Copenhagen, 1935) ferments mannose and 

 sucrose but not arabinose. 



Hydrolyzes starch actively in alkaline 

 media. 



Nitrites produced from nitrates. 



High alkali but low acid tolerance: 

 optimum pH, between 7.6 and 8.0; for 

 isolation on Dieudonne's medium, pH 9.0 

 to 9.6. 



Aerobic, grows best in abundant oxygen; 

 under strict anaerobiosis may fail to grow 

 altogether. 



Optimum temperature, 37° C. Maximum, 

 42° C. Minimum, 14° C. 



Source: Isolated from the intestinal 

 contents of cholera patients in Egypt and 

 India. 



Habitat: Found in the intestinal contents 

 of cholera patients and carriers. 



The relationships existing among the 

 cholerigenic and non-pathogenic water 

 vibrios, although studied intensively, have 

 not yet been completely defined. As a 

 working scheme, based on somatic (O) and 

 flagellar (H) antigen studies, Gardner and 

 Vankatraman (Jour. Hyg., 35, 1935, 262- 

 282) suggest the one shown in the graph 

 on the following page. 



Linton (Bact. Rev., 4, 1940, 275) has out- 

 lined a classification of the vibrios based 

 upon their protein and polysaccharide struc- 

 tures. Using chemical methods, it was found 

 that one polysaccharide and one protein 

 was commonly obtained from each strain 

 of vibrio; when exceptions occurred, it was 

 invariably noted that the strain was under- 

 going dissociation. Given a single protein 

 and polysaccharide in each vibrio, it was 

 possible to divide the strains into six groups, 

 which were numbered in the order of their 

 discovery as shown in the table. 



A chemical grouping of the cholerigenic 

 and water vibrios. 



The strains of Groups I and II possess 

 the same protein and different polysaccha- 



