LACK OF CORRELATION BETWEEN PLASMID-ASSOCIATED PHENOTYPES OF YERSINIA-ENTEROCOLITICA AND PATHOGENICITY IN THE MOUSE

Various phenotypic characteristics have been correlated with the patho genicity of plasmid-bearing virulent strains of Yersinia enterocolitic a. Two transposon Tn801-insertion derivatives (JD193 and JD217) of the virulence plasmid from serotype 0:3 were used to determine the correl ation between pathogenicity and plasmid-associated properties of this organism. Both Tn801-inserted derivatives expressed five plasmid-assoc iated phenotypic characteristics at 37C: (1) colony morphology, (2) ca lcium-dependent growth or low-calcium response, (3) crystal violet bin ding, (4) autoagglutination, and (5) hydrophobicity. However, for mous e pathogenicity only JD193 was positive whereas, JD217 was avirulent f or mice. Thus, it is possible to have a lack of correlation between pl asmid-mediated traits and the actual pathogenicity of the organism in the mouse; however, these plasmid-mediated phenotypic characteristics provide simple and efficient techniques to evaluate the virulence pote ntial of wild-type strains isolated from food poisoning outbreak and c linical cases.