Interaction between T. vaginalis and P. aeruginosa was studied in vitro. Protozoan cells were incubated in 0,9% NaCl at 37°C for 30 and 150 min. with bacteria, alive or killed by heating for 10 min. at 100°C. Transmission electron microscope observations showed weak fagocytic activity (<10%) of T. vaginalis against living P. aeruginosa. Phagocytosis of these bacteria caused death of T. vaginalis. Desintegration and autolysis of T. vaginalis resulted probably from action of exotoxin A produced by P. aeruginosa. Phagocytosis of dead P. aeruginosa has not been observed.
Trichomonas vaginalis was incubated with bacteria for 30 min. After centrifugation of Staphylococcus aureus, incubation of T. vaginalis was continued for 40 min., 120 min. and 6 hrs. It was found that bacteria have been intensively phagocytated through whole surface of protozoan. Phagosome with bacteria at different stages of degradation, up to defecation of undigested residues were observed. It was observed that some bacteria, apparently not susceptible to digestion, were immersed directly in cytoplasm (outside vacuoles).