Figure 5.

Growth in vitro and in vivo of wild-type and siderophore-deficient H37Rv. (A) Growth curves of wild-type H37Rv in low-iron GAST (●) and ΔmbtB∷hyg in low-iron GAST medium supplemented with 5 μM iron, 0.5 μM iron, and 0 μM iron (□, ▵, and ○, respectively). The growth curve for wild type in any of these iron concentrations is superimposable with the iron-deficient growth curve. (B) Growth of wild-type (●) and ΔmbtB∷hyg (○) H37Rv in the human macrophage-like cell line THP-1 over a 9-day infection. Inset demonstrates that the number of input organisms and the number of organisms internalized after 2 hr of infection were similar between the wild type (open bars) and mutant (shaded bars). (C) Growth of wild-type and ΔmbtB∷hyg H37Rv when the inocula were prepared from medium containing different concentrations of iron. The first four bars at each time point represent wild type, and the second four bars represent mutant. In each series the iron concentration increases from left to right as 0, 0.5, 5, and 500 μM iron. The organisms were passed for 2 days in medium of the indicated iron concentration before infection.