[Examination of selected biological properties for swarm cells in Proteus mirabilis]

Certain biological properties, which generally are thought to play a role in the bacterial pathogenicity, were compared in short rods, swarm cells and penicillin-induced filaments of Proteus mirabilis S1959. Swarm cells of P. mirabilis S1959 weakly adhere to human uroepithelial cells and also do not penetrate L929 line of mouse fibroblasts. They do not show any cytotoxic activity, are poorly phagocytized by macrophages and granulocytes and start to divide by the end of the phagocytosis process. Their well-marked cell-bound haemolytic activity is correlated with fast division to the short rods. In in vivo experiments we have demonstrated the presence of long filamentous multinucleate nonseptate cells in the bladder and in the kidneys of infected animals. However there was no correlation between the number of swarm cells seen under microscopic examination and the intensity of infection.