Characterization of Yersinia pseudotuberculosis serogroups O9, O10 and O11; subdivision of O1 serogroup into O1a, O1b, and O1c subgroups.

In this study, three new antigens (O9, O10 and O11) of Yersinia pseudotuberculosis are described. The O1 antigen is further subdivided into O1a, O1b and O1c. The methods used to prepare specific antisera for O-antigen identification are also described. Furthermore, the H antigens of these new serogroups are determined and their biochemical characteristics analysed. The antigenic formulae of the known serogroups within the basic antigenic scheme introduced by the authors' laboratories are presented.