Yersinia enterocolitica : Biochemical, Serological, and Gas-Liquid Chromatographic Characterization of Rhamnose-, Raffinose-, Melibiose-, and Citrate-Utilizing Strains

Abstract

Atypical Y. enterocolitica isolates (13), all fermenting rhamnose, raffinose, and melibiose and utilizing sodium citrate within 24-48 h at 22.degree. C (Y.e.rh+), were examined biochemically-serologically, and by GLC. These data, and cultural, biochemical and antibiotic susceptibility data gathered from 2 previous studies involving these same atypical Y.e.rh + isolates, Y. enterocolitica serotypes 0:1 through 0:15 (rhamnose, raffinose and citrate negative [Y.e.rh-]) Y. enterocolitica serotype 0:16 (rhamnose positive but raffinose and citrate negative) and Y. pseudotuberculosis serogroups I through V, were statistically compared. Pre- and postabsorption agglutination studies demonstrated the serological distinctiveness of Y.e.rh+ from Y.e.rh- and Y. pseudotuberculosis. At the same time, 3 immunological groups among the 13 Y.e.rh+ strains were seen; 8 corresponded to Y. enterocolitica serotype 0:17; 1 to Y. enterocolitica serotype 0:16; and the remaining 4 were nontypable in antisera against known Y. enterocolitica antigen types. Each of the 3 Yersinia groups tested chromatographically produced acetic and lactic acids. Both Y.e.rh- and Y.e.rh+ formed propionic acid, but only Y.e.rh+ produced detectable amounts of succinic acid. Based on 49 variables, statistical analysis of the 3 Yersinia groups studied placed each of the Y.e.rh+ strains in a homogeneous group separate from Y.e.rh- and Y. pseudotuberculosis. These data, coupled with DNA homology studies of Brenner and co-workers, support the distinctiveness of Y.e.rh+ from typical Y. enterocolitica and Y. pseudotuberculosis.