Interrelationship of certain Shigella and Escherichia cultures.

The relationships observed among several serotypes of Enterobacteriaceae make it desirable to discuss the following in one paper: 1. ShigeUa dysentriae 2 (ShigeUa ambigua). 2. Escherichia coli 0 group 112 a,c of Ewing and Kauffmann (1950) (Shigella guanabara of de Assis, 1948). 3. Escherichia coli, strain 6182-50 (representative of a new E. coli 0 group, 113). 4. Escherichia coli 0 group 112 a,b of Ewing and Kauffmann (1950). 5. Culture no. 703, a Shigelka-like bacterium. de Assis (1948) reported that the cultures which he called S. guanabara did not share antigens with any of the known shigellae. Later, de Assis (1950) reported that a heated suspension of one Guanabara culture exhibited a serological relationship to S. dy8enteriae 2 but that it was possible to distinguish between the two types. The eleven Guanabara cultures (E. coli 0 group 112 a,c) used in this study were received from Dr. de Assis and were the same as those employed in -the work reported by Ewing and Kauffmann (1950). The culture of E. coli 0 group 112 a,b (1411-50) was isolated by Dr. H. R. Wolfe from a case of gastroenteritis in a nine-month child and was sent from the Massachusetts State Department of Health to this laboratory for identification. The cultures of S. dysenteriae 2 were received for typing and gave typical biochemical and serological reactions. Culture no. 6182-50 was isolated by Dr. J. Olarte from a case of diarrhea in a prematurely born infant in Mexico City. The biochemical reactions given by culture 6182-50 are those of a typical E. coli culture. Culture no. 703 was isolated by Dr. H. Gezon of the U. S. Navy Epidemiology Unit 23 in Salerno, Italy, during 1944. Dr. Gezon sent the culture to the senior author in Naples for comparison with other unidentified Shigella-like cultures. Culture no. 703 was recovered from feces, but it is not known whether it came from a case or a carrier. The 0 antiserums used in this work were prepared with broth cultures that were heated at 100 C for 21 hours, according to the procedures outlined by Kauffmann (1947, 1951b). Suspensions to be used for adsorption of agglutinin from 0 antiserums were heated at 100 C for 1 hour. Broth culture 0 antigens used in agglutination tests were also heated at 100 C for 1 hour. Antiserums for the flagellar (H) and thermolabile K antigens of the bacteria were prepared after the methods given by Kauffmann (1947, 1951a), and tests with the antiserums were performed in the manner advised by that investigator. For other references