Figure 4 - Clearance of E. coli B41 in germfree (squares) or heat-killed L. acidophilus UFV-H2b20-treated Swiss mice (circles). Germfree mice received 108 cells of L. acidophilus intragastrically daily for 7 days. E. coli B41 was injected into the tail vein and blood samples were taken from the retro-orbital plexus at 0, 15, 30, 60 and 90 min after injection. Ten-fold serial dilutions of blood were plated and cultured on Petri dishes containing MacConkey medium. Dishes were incubated overnight at 37oC and colonies counted. The results are reported as percent viable cells per ml blood in relation to time 0. Each point is the average of data for 5 mice from one representative experiment of two performed. Vertical bars indicate standard deviation of the means. *P0.05 compared to monoassociated mice (Student t-test).