[Collection of Shigella strains of provisional serovars. II. Antigens and antigenic relations].

In the serological study of 17 strains from the collection of Shigella provisory serovars (3873-50, 2000-53, 3341-55, 3615-53, 2710-54, 1621-54) differences in the content of K-antigens were revealed: some of them (3341-55, 3615-53) were in the K-form, others (2000-53, 1621-54) in the O-form, and the rest in the OK-form. No antigenic affinity between the representatives of the enterobacterial group under study was established. The partial composition of O-antigen in bacteria of serovar 2000-53 and antigenically affined E. coli strains, serogroup 06, was studied. E. coli 06 O-antigen was shown to be heterogeneous and had the structure of type a, b--a, c. On the basis of the antigenic structure thus established, as well as its cultural and biochemical properties described in earlier works, serovar 2000-53 should be excluded from the group of Shigella provisory serovars and classified with the genus Escherichia under the designation E. coli 06a. 6b : K? : H--.