[Characterization of hemolytic activity of Proteus penneri].

Bacteria belonging to the genus Proteus synthesise two kinds of hemolysins HpmA and HlyA which represent "RTX proteins". In previous papers we described the production of an extracellular HlyA hemolysin by some P. penneri strains. Now we are reporting on the synthesis by P. penneri, typical for P. mirabilis HpmA hemolysin. There were identified two P. penneri strains 5 and 37 in which both hpmA and hlyA regions are present. In two other strains P. penneri 13 and 44 only hlyA region was found, whereas in strain P. penneri 42 operon hpmA was identified. The production of HpmA hemolysin was revealed in the cases of P. penneri 5, 42 and P. mirabilis 03 and 1959. The dynamics of HlyA hemolysin synthesis by P. penneri 44 was also investigated and its highest activity was observed during logarithmic phase of growth of bacterial culture. HlyA hemolysin was isolated from culture filtrate by precipitation with polyethylene glycol 4000. The invasiveness of HpmA+ and/or HlyA+ P. penneri strains was also checked by use of mouse L929 fibroblasts. Both kinds of strains were able to penetrate tested cells. The invasion of L929 fibroblasts by strains producing HlyA hemolysin is accompanied by cytotoxic effect.