Growth of S. aureus strains in Chelex treated RPMI with 0.75 mM EDDHA either in the absence (A) or presence (B) of 1 μM heme. A, Under iron deplete conditions lacking heme, ΔisdGI plgt.isdI (dark grey) exhibits reduced growth compared to any of the other strains. B, When grown in the iron limited conditions in the presence of heme, the endogenously expressed strains (ΔisdGI pisd.isdI and ΔisdGI pisd.isdG) exhibit enhanced growth as compared to constitutively expressed strains (ΔisdGI plgt.isdI and ΔisdGI plgt.isdG). 2-way ANOVA analysis was applied to the 10 hour time point for each growth curve (p<0.05), error bars represent S.E.M..