INVITRO ASSESSMENT OF VIRULENCE IN YERSINIA-ENTEROCOLITICA AND RELATED SPECIES

Abstract

We have examined 136 isolates of Yersinia species, comprising 112 strains of Yersinia enterocolitica, 12 of Y. frederiksenii, 8 of Y. intermedia, and 5 of Y. kristensenii, for the presence of 40- to 50-megadalton virulence-associated plasmids and expression of the following plasmid-associated characteristics: Congo red pigmentation (CR), calcium dependence, autoagglutination, hydrophobicity, resistance to normal human serum, and pathogenicity in mice. All 136 strains yielded both pigmented (CR+) and nonpigmented (CR-) variants. Only CR+ variants, however, were virulent for iron-overloaded, desferrioxamine B-treated mice (R. M. Robins-Browne and J. K. Prpic, Infect. Immun. 47:744-779, 1985). ..