[New results on the phage typing of Yersinia enterocolitica, concerning more of 4 000 strains of various origins (author's transl)].

1. The phage typing of Y. enterocolitica has been made on more than 4,000 strains of various origins by means of 2 sets of phages. The 1st one, composed of 12 phages extracted from lysogenic strains of the same species has permitted to distinguish 10 phages types numbered from I to VIII and from IXa to IXb among the 3,323 lysotypable strains on the 4,366 examinated. 2) The search of the beta-galactosidase has differentiated the phage type IXa in its 2 varieties, the IXa 1, beta-galactosidase negative and the IXa 2, beta-galactosidase positive. 3) The 1,043 untypable strains by the 1st set were forming 2 very different groups. One of them, the X was insensitive to the 12 phages of the 1st set; the other XI, showed such a variety of lytic reactions to the phages of the 1st set that it was impossible to consider the rare samples of each of them as phage types. 4) The group X, submitted to a "complementary phage typing" by means of a second set of phages isolated from sewage water, has been subdivised into about 20 undergroups, from which only, 7 have been studies up to now, numbered from X 1 to X 7...