Characterization of plasmids and plasmid-associated determinants of Yersinia enterocolitica pathogenesis

Abstract

Yersinia enterocolitica isolates harboring a particular species of plasmid deoxyribonucleic acid showed a high degree of lethality for gerbils and caused the detachment of HEp-2 tissue cell monolayers. Strains cured of their plasmid deoxyribonucleic acid showed loss of these properties. However, invasiveness of HEp-2 cells was shown not to be a plasmid-mediated property. The expression of plasmid-associated properties, including at least three major outer membrane polypeptides, occurred during growth at 37 but not at 25°C and was related to the concentration of calcium in the growth medium. The plasmid species associated with these properties ranged in molecular mass from 40 x 106 to 48 x 106 daltons and comprised a family of related plasmids.