520 



VIBRIO 



Venkatraman (1935) have done much to clarify the confusion resulting from the 

 work carried out before the importance of flagellar and somatic antigens had been 

 appreciated. The analysis is, however, by no means complete, and the scheme 

 reproduced here must be regarded only as a working hypothesis, certain in the future 

 to require considerable modification. 



Attention has been concentrated mainly on the cholera and cholera-Uke vibrios, 

 which we refer to for convenience as Group A. This group comprises organisms, 

 most of which produce acid without gas in glucose, maltose, mannitol, and sucrose, 

 but not in dulcitol, and which give the cholera-red reaction. All organisms of 

 Group A possess a common H antigen. The major antigens, on the other hand, 

 of which six have already been differentiated, are much more specific and are 

 used as a basis for the differentiation of Group A into sub-groups. The true cholera 

 vibrios all appear to fall into sub-group I, which also contains most of the El Tor 

 strains. Sub-groups II to VI contain organisms, referred to as paracholera and 

 cholera-like, that have been isolated from cases of choleraic diarrhoea or from water. 

 Thus, according to Gardner and Venkatraman, the true cholera vibrio is a non- 

 hsemolytic organism containing the specific antigen of sub-group I ; except by 

 hsemolysin production it is indistinguishable from El Tor vibrios containing the same 

 antigen. A non-specific antigen, shared to a variable extent by all the members 

 of Group A, has also been described by these workers. 



Vibrio 



Group A. Cholera and cholera-like vibrios. 

 General biochemical similarity. 

 Common H antigen. 



Group B. Non-cholera-like vibrios. 

 Biochemically distinct from Group A, 

 with less fermentative ability. Little 

 exact knowledge of antigenic 

 structure. 



sub-group I. 



Non-hsemol5^ic. 

 Cholera vibrios. 

 At least 3 types 

 differentiated on 

 minor antigens. 



Haemolytic. 

 El Tor vibrios. 

 At least 2 types 

 differentiated on 

 minor antigens. 



sub-groups II, III, IV, V, VI, 



and individual races. Mostly 



hsemolytic. 

 Paracholera, cholera-like, and 



some El Tor vibrios. 

 Types within sub-groups 



undetermined. 



Fig. 104. 



Chemical Analysis. — The chemical analysis of the Vibrio group has been intensively 

 studied of late years by Linton and his colleagues in India (for early references see Linton, 

 Shrivastava, and Mitra 1935), who followed up the work of Landsteiner and Levine (1927). 

 They find that the vibrios can be classified into six groups on the basis of two protein 

 and three polysaccharide constituents (Table 34). 



Proteins I and II show wide structural differences, but whether they are quahtatively 

 distinct, or whether each is a mixture of several proteins, is not yet decided (Mitra 1938). 

 The polysaccharides exist in the cell as acetyl compounds (Linton and Mitra 1936). On 

 hydrolysis polysaccharide I yields galactose and aldobionic acid, polysaccharide II ara- 

 binose and aldobionic acid, whereas the polysaccharide complex III yields glucose only. 

 It is doubtful how far the polysaccharides can be regarded as distinct compounds ; Linton, 

 Shrivastava and Seal (1938). for example, have found big differences in the physical, 

 chemical and antigenic properties of preparations of a polysaccharide formed by a given 

 vibrio grown on different media. Metabohc studies by Linton, Mitra and Mullick (1936a, b) 



