FIG 5.

Growth of USA100 strains in the presence of a sub-MIC of cefoxitin. (A, B) The strain 103 (A) and 111 (B) WT strains demonstrated growth superior to that of the paired Δagr mutants when exposed to cefoxitin, suggesting that a functional agr system in these strains contributes to survival under antibiotic stress. (C, D) Growth curves for representative strains 134 (C) and 139 (D) in which no differences in growth were observed between each of the strains in the strain pairs tested with the same concentration of cefoxitin.