Serological relationships between shigella and coliform cultures.

Definitive studies of the serological relationships between members of the E&chericki coli group and other groups within the family Enterobacteriaceae were made possible by the differentiation of the thermolabile and thermostable somatic antigens of E. coli cultures (Kuffmann, 1943, 1944a) and the subsequent introduction and establishment of the Kauiffmann-KnipschildVahlne antigenic schema. As introduced by Kauffmann (1944b, 1947), the diagnostic schema consisted of the 25 0 antigen groups that occurred most frequently, 55 thermolabile envelope or K antigens, and 20 agellar or H antigens. The E. coli schema now consists of 124 0 antigen groups, 60 K antigens, and 33 H antigens. E. coli cultures now may be typed accurately by determination of their 0, K, and H antigens. For further discussion of the E. coli group and of typing methods, the reader is referred to the publications of Kuffmann (1947, 1951a, b), Kauffmann and Dupont (1950), and 0rskov (1952). Wheeler and Stuart (1946) reported that the somatic antigens of two coliform microorgani were identical with those of Shigella dysenteriae 3 and called attention to a relationship between the antigens of Shigella dywnteriae 1 and those of Alkalescens-Dispar 0 group 1 (ShigeUa alkalescens). These investigators tested 14 alkalescensDispar 0 group 1 cultures in eight S. dywnteriae 1 antiserums and obtained agglutinative titers which varied from 1:160 to 1:5, 120. When S. dysen&eriae 1 cultures were tested in AlkalescensDispar 0 group 1 antiserums and in antiserums prepared with certain other coliform bacteria, positive but weaker reactions were obtained. This relationship also was noted by Wheeler et al. (1946) and was confirmed by the writer. In 1947, Ferguson and Henderson described a coliform bacterium, culture C27, that possessed somatic antigens identical with those of form I (smooth) Shigella sonnei. The writer confirmed this relationship and also found that the 0 antigens of C27 and of S. sonnei cultures were not related to any of the 124 E. coli 0 antigen groups. Early in 1952 a culture (602-52) similar to C27 was received from Dr. Vandepitte who isolated it in Belgian Congo from a patient with dysentery, from whom S. 8onnei also was isolated. Ferguson (1952) stated that cultures similar to C27 have been isolated in Michigan since 1947 and that they occurred in association with S. 8onnei in some cases. Another culture of this type was received recently from Dr. E. Schmid, Colombo, Ceylon. Veazie (1950) reported that close antigenic relationships existed between cultures of Shigella boydii 4 and E. coli 0 group 53 and between S. boydii 5 and E. coli 0 group 79. The writer confirmed this report and found that the 0 antigens of S. boydii 4 and S. boydii 5 were identical with those of E. coli 0 group 53 and 79, respectively, as demonstrated by reciprocal agglutinin adsorption tests. These results were confirmed by Kauffmann (1950) and by Odden (1951), who also reported that the 0 antigens of S. dywenriae 5 cultures were identical with those of E. coli 0 group 58 and that those of S. boydii 2 and E. ccli 0 group 87 were related closely but were not identical. Odden's results were confirmed in this laboratory in connection with studies on the thermolabile somatic antigen of S. boydii 2 cultures (Ewing et al., 1951a). Ewing et al. (1951b, c) reported that the 0 antigens of provisional S. boydii 9 and E. coli 0 group 102 bore a strong reciprocal relationship and that the 0 antigens of provisional S. boydii 10 and E. coli 0 group 105 cultures were related similarly. They also reported that the 0 antigens of provisional S. boydii 11 were identical with those of E. coli 0 group 105. Ewing, Hucks, and Taylor (1952) reported that the 0 antigens of S. dysentriae 2 and Shigella serotype 703 were identical with those of E. coli 0 groups 112a, 112c, and 112a, 112b, respectively. The relationships of the 0 antigens of Shigella serotypes 387350, 425, 123, and 2770-51 to E. coli 0 antigen