FIG. 3.

Roles of FCT region genes in virulence at the skin. Bacteria grown to either mid-logarithmic (filled symbols) or stationary (open symbols) phase in broth culture were used to inoculate scratched human skin engrafted on SCID mice. The inoculum dose (log₁₀ CFU) is depicted on the x axis. The net change (increase or decrease) in log₁₀ CFU recovered from a graft at biopsy, relative to the inoculum dose, is shown on the y axis. Each data point represents an inoculated skin graft. Bacterial inocula are indicated for wt ALAB49 and the Δcpa, ΔfctA, and ΔprtF2 mutants. Statistically significant differences (P values for two-tailed unpaired t test) between the net change in graft-recovered CFU for inocula prepared to the logarithmic versus stationary phase of growth are shown. The statistical significances of differences between the net change in graft-recovered CFU for wt ALAB49 versus each of the mutants, for the two inoculum conditions, are reported in the text. All data comparisons that were statistically significant by the unpaired t test were also significant by the Mann-Whitney U test, and vice versa (data not shown). NS, not significant.