[Use of factor-H sera for the differentiation of the flagellar antigens of Escherichia coli serological variants].

The use of factor sera permitting the differentiation of the variants, described in earlier. works, among the flagellar antigens of E. coli, formally denoted as H2, H4, H7, H10 and H34 in accordance with their official nomenclature, has made it possible to reveal that each of these variants is widely spread among E. coli and occurs in bacteria of different O-groups. Besides, this study has shown the possibility of subdividing a number of formal H: O types into 2 or more serovars on the basis of differences in the factor composition of their antigens. The results obtained in this study suggest that in the process of the evolution of E. coli H-antigen variants differing in their factor composition have been formed as independent varieties; therefore, these variants do not reflect the features characteristic of individual strains, but constitute one of the diagnostic signs of serological classification, i. e. the differentiation of the species into various serovars.