FIG 2.

In vivo competition between ST15/9-47 (ear isolate) and ST15/4495 (blood isolate). Data shown are pooled from two competition experiments performed with 5 mice per group for each time point (24 h and 72 h postchallenge). In one experiment, mice were challenged with equal numbers (5 × 10⁷ CFU each) of ST15/4495 and ST15/9-47:pAL3 (open symbols); in the other experiment, mice were challenged with equal numbers of ST15/4495:pAL3 and ST15/9-47 (solid symbols). The competitive index (CI) is shown as log₁₀ CI for each tissue of each mouse. The horizontal dotted lines denote the geometric mean CI for each tissue. Statistical differences between the log-transformed geometric mean CI and a hypothetical value of 0 (ratio of 1:1) in each niche were analyzed using the two-tailed Student's t test. ns, not significant; *, P < 0.05; ***, P < 0.001; ****, P < 0.0001.