Interaction between Yersinia pseudotuberculosis and Y. enterocolitica and fish cells.

Virulent strains of Yersinia pseudotuberculosis and Y. enterocolitica cultured at 10 degrees C were studied with respect to their interaction with cultured fish cells. Infection with Yersinia at 25 degrees C resulted in the formation of pseudopodia and the adherence of bacteria to the cell surface. The adherent bacteria were ingested 2 h after infection. Yersinia was found to be cytotoxic for the cells and the intracellular bacteria seemed to reside in phagosomes and were found in stages of division but were never observed in the nucleus.