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Four isolates of Yersina enterocolitica and six of Y. pseudotuberculosis were made from carcasses collected in Ontario in 1973. Y. enterocolitica was isolated from the following species: Canada goose, Branta canadensis (serotype 4,33), Pekin robin, Leiothrix lutea (serotype 6,30), beaver, Castor canadensis (serotype as yet unknown), and raccoon, Procyon lotor (serotype 5,27). Yersiniosis was apparently the cause of death of the beaver and the cause of liver abscesses in the raccoon; the significance of the isolates from the birds was not determined. Y. pseudotuberculosis isolations were from a crow, Corvus brachyrhynchos (serotype 1A), two purple martins, Progne subis (serotype 1B), and three beavers (serotype 1B). Yersiniosis was apparently the cause of abscesses in one of the beavers and the cause of death of the other cases. During the period from 1962 to 1972, Y. pseudotuberculosis had been isolated in this laboratory from four beavers and one snowshoe hare, Lepus americanus. There was no record of pr...

Seventeen cases of mesenteric adenitis were investigated between May and October, 1959, for the presence of virus as well as for evidence of Pasteurella pseudotuberculosis infection. Specimens examined included mesenteric glands, appendix, throat swab, faeces, and serum, although glands were received from only 12 patients. Virus was not isolated from any of the specimens, but evidence of infection with Pasteurella pseudotuberculosis was obtained in three patients. The three cases of acute mesenteric lymphadenitis due to Pasteurella pseudotuberculosis are reported. Pasteurella pseudotuberculosis Type IA was isolated from the mesenteric glands of two of the cases, and all three cases showed serological evidence of infection with the organism. The mesenteric glands of two of the cases showed histological changes characteristic of pseudotuberculosis.

SUMMARY: From strains of Pasteurella pseudotuberculosis representing each of the five serological groups and some ‘Rough’ forms, lipopolysaccharides were isolated after disintegration of acetone-dried saline extracted organisms with phenol. The materials appear to carry the specificities on which the serological classification of the species is based; they are relatively poor antigens when isolated but antigenicity can be enhanced by combining with lipoprotein. Analyses show some unusual features, an aldoheptose sugar being present in all of the materials and some of the ‘Smooth’ cell products contain dideoxy sugars; rhamnose is absent. The ‘Rough’ cell products are somewhat similar in composition to the ‘Rough’ somatic polysaccharide of Pasteurella pestis, to which they are also related serologically.

SUMMARY: The serological specificities of lipopolysaccharides obtained from representatives of each of the five serological groups of Pasteurella pseudotuberculosis have been examined by haemagglutination methods. At concentrations of 500 μg./ml. solutions of the lipopolysaccharides failed to give full sensitization of erythrocytes, but after treatment with alkali full sensitization was obtained at concentrations in the range of 50 to 3 μg./ml. By using antisera prepared in rats by immunization with living P. pseudotuberculosis, the capacity of each ‘Smooth’ lipopolysaccharide to inhibit the agglutination of sensitized erythrocytes by each group antiserum was determined. Absolute group specificity was found by this method. It is considered that the lipopolysaccharides bear the specificity of the somatic antigens on which the serological grouping of the species is based. ‘Smooth’ P. pseudotuberculosis lipopolysaccharides failed to inhibit the agglutination by P. pestis antisera of erythrocytes sensitized with P. pestis lipopolysaccharide, but inhibition of this system was obtained with lipopolysaccharides of ‘Rough’ P. pseudotuberculosis strains derived from various serological groups. These ‘Rough’ lipopolysaccharides were closely related serologically to one another and to the P. pestis product but were not identical in specificity. It is considered that in Smooth P. pseudotuberculosis strains the ‘Smooth’ somatic antigen does not overlie a ‘Rough’ somatic antigen.

SummaryBacteriophage, originally recovered as a lytic agent for P. pestis, also lysed 31 of 40 strains of P. pseudotuberculosis. After adaptation to one of these (Spokane strain), it also lysed the remaining nine strains. When the adapted phage was transferred on S. dysenteriae, it reverted to its original activity; i.e., it again failed to lyse the nine strains of P. pseudotuberculosis which resisted the original phage. Activity for all strains was restored by transferring it on the Spokane strain. Lysates of S. dysenteriae, mixed with the adapted phage, caused no reversion to the original selective activity for only 31 strains of P. pseudotuberculosis. Transfers of the adapted phage on S. para-dysenteriae, S. sonnei, S. ambigua, or on all of these species in succession, did not alter its ability to lyse all strains of P. pseudotuberculosis. The size of plaques did not change during transfers on either the shigellae or the pasteurellae used.

Summary A case of Yersinia pseudotuberculosis septicaemia is described in a patient with sickle-cell anaemia. This is believed to be the first reported instance of human infection with serotype V. The possibility that disordered iron metabolism might be the predisposing factor in this and other Y. pseudotuberculosis septicaemias is considered. We are grateful to Dr N. S. Mair for serotyping the strain, for antibody studies and for general interest, and to Dr A. G. Beckett under whom the patient was admitted.

SummaryIt has been shown that high speed vibration of cells of P. pestis in the presence of “ballottini” is accompanied by disintegration of the bacillary forms with concurrent release of antigenic material. At least one antigen was present in the lysed material which could not be demonstrated when cells were not lysed. 2. P. pestis and P. pseudotuberculosis appear to share 2 free “envelope” antigens as well as a single somatic antigen. In addition, it has been shown that P. pestis possesses a minimum of 1 “envelope” and 3 somatic antigens which are not shared with P. pseudotuberculosis. No antigens which could be considered specific for P. pseudotuberculosis were revealed.