FAMILY PSEUDOMONADACEAE 



195 



Cholera group of vibrios. 

 (Biochemically similar. Common H antigen.) 



0-sub-group I. 



Non-hemolytic 

 (goat cells). 

 Cholera vibrios. 

 Types — original, 

 variant and 

 middle. 



Hemolytic (goat 



cells). 



El Tor vibrios. 



Types — original 



and variant 



(Pmiddle). 



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

 outlined a classification of the vibrios 

 based upon their protein and poly- 

 saccharide structures. Using chemical 

 methods, it was found that one poly- 

 saccharide and one protein was com- 

 monly obtained from each strain of 

 vibrio; when exceptions occurred, it was 

 invariably noted that the strain was 

 undergoing dissociation. Given a single 

 protein and polj'saccharide 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 cholerigcnic 

 and water vibrios. 



Polysaccharide 

 Type 



I 



II 



II 



I 



III 



III 



The strains of Groups I and II possess 

 the same protein and different poly- 

 saccharides. These are derived from 

 cases of cholera and have the serological 



O sub-groups II, HI, IV, V, VI and 



individual races (mostly hemolytic). 

 Paracholera, cholera-like, and some 

 El Tor vibrios. 



(Types \Yithin sub-groups underlined.) 



and biochemical characteristics of O- 

 Group I, Vibrio cholera. Group I strains 

 are more common than those of Group 

 II, which have, however, been isolated 

 from epidemics with a high mortality. 

 The phospholipid fraction is common to 

 both types when isolated in the early 

 part of an epidemic, but is not found in 

 strains of other groups. The harmless 

 water vibrios, which are so heteroge- 

 neous serologically (Taylor and Ahuja, 

 Indian Jour. Med. Res., 26, 1938, 8-32) 

 form a single chemical group with a 

 homogeneous structure. They fall into 

 Group III, which differs in its protein 

 structure from the authentic cholera 

 vibrios, and resembles Group II in its 

 polysaccharide. The vibrios of Group 

 IV, which came from El Tor and from 

 chronic vibrio carriers are believed on 

 epidemiological grounds to be harmless, 

 although serological methods have failed 

 to distinguish them from cholerigcnic 

 vibrios. Group V, which, like III and 

 IV, contains protein II, consists, like 

 Group IV, of strains from chronic vibrio 

 carriers. Group VI strains are only 

 rarely isolated in nature and representa- 

 tives of this group are generally found 

 among collections of old laboratory 

 strains. They appear to be the result of 

 polysaccharide variation from Group I 



