FIG. 1.

Effects of the amount of inoculum (top) and burn size (middle and bottom) on survival in the model with E. coli O18:K1:H7. In the experiment shown in the top panel, all burns were 4 in² in area. Rats under all inoculation conditions had significantly greater mortality (P ≤ 0.0001) than uninfected burned rats. As shown in the middle panel, rats with the 2-in² burn had significantly less mortality (P ≤ 0.002) than those with either the 8- or the 4-in² burn receiving either amount of inoculum. As shown in the bottom panel, survival of rats with one infected burn of 2 in² and an additional burn of 2 in² was significantly greater than survival of rats with a single infected 4-in² burn (P < 0.0001). However, there was no significant difference in survival between rats with one infected burn of 2 in² and an additional uninfected burn of 2 in² and rats with a single 2-in² infected burn receiving either 20 (P = 0.50) or 200 (P = 0.25) CFU.