A highly virulent strain of Yersinia pseudotuberculosis (LD50 c. 102 bacteria/mouse) harboured two plasmids with mol. wt of 47 × 106 and 61 × 106. The role of these plasmids in virulence was studied in mice with derived strains cured of plasmids. It was confirmed that the plasmid of mol. wt 47 × 106 played a major function in virulence. This was shown both by the increase of the LD50 and the lower rate of multiplication in the spleen obtained with strains cured of the plasmid of mol. wt 47 × 106. The plasmid of mol. wt 61 × 106 did not play any role in virulence. This work also demonstrates that the strain cured of the plasmid of mol. wt 47 × 106 and the plasmid-free strain were able to multiply in the spleens of infected mice during a 7-day period. This suggests that virulence factors not associated with plasmids are also responsible for the bacterial growth in tissues in vivo.
BölinI.,
NorlanderL.,
Wolf-WatzH.1982; Temperature-inducible outer membrane protein of Yersinia pseudotuberculosis and Yersinia enterocolitica is associated with the virulence plasmid.. Infection and Immunity 37:506–512
CuzinF.,
JacobF.1967; Mutations de l’episome F d’Escherichia coli K.12. 2. Mutants a replication thermosensible.. Annales de l’lnstitut Pasteur 112:397–418
GemskiP.,
LazereJ. R.,
CaseyT.1980a; Plasmid associated with pathogenicity and calcium dependency of Yersinia enterocolitica. Infection and Immunity 27:682–685
GemskiP.,
LazereJ. R.,
CaseyT.,
WohlhieterJA.1980b; Presence of a virulence-associated plasmid in Yersinia pseudotuberculosis. Infection and Immunity 28:1044–1047
MazighD.,
ChalvignacM. A.,
AlonsoJ. M.,
MollaretH. H.1983; Determinisme genetique de la virulence de Yersinia enterocolitica et de l’immunogénicité croisee contre Yersinia pestis. In Les bacilles à Gram négatif d’intérêt medical et en Santé Publique: Taxonomie-Identifica tion-Applications, les Colloques de 1’INSERM.. INSERM 114:517–535
PortnoyD. A.,
MoseleyS. L.,
FalkowS.1981; Characterization of plasmids and plasmid-associated determinants of Yersinia enterocolitica pathogenesis.. Infection and Immunity 31:775–782
SimonetM.,
BercheP.,
MazighD.1983; Une septicemie due a une souche hautement virulente de Yersinia pseudotuberculosis. Medecine et Maladies Infectieuses 13:767–771