Figure 1 - Clearance of E. coli B41 in germfree (squares) and conventional (circles) Swiss mice. E. coli B41 was injected into the tail vein and blood samples were taken from the retro-orbital plexus at the time of injection and 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 mean for 5 mice of one representative experiment of three performed. Vertical bars indicate standard deviation of the means. *P£0.05 compared to conventional mice (Student t-test).