Iron Deprivation Affects Drug Susceptibilities of Mycobacteria Targeting Membrane Integrity

Figure 2

Drug susceptibility assays against M. smegmatis in response to iron deprivation. (a) Broth microdilution to determine the MIC₈₀ of M. smegmatis in the presence of EMB, INH, and RIF (62.5 ng/mL, 1 μg/mL, and 62.5 ng/mL) alone and in the presence of 2,2, BP, DFO, and BPS (35 μg/mL, 656 μg/mL, and 386 μg/mL), respectively, to determine the effect of iron deprivation on susceptibilities of EMB, INH, and RIF. Data was quantitatively displayed with color (see color bar in left panel), where each shade of color represents relative optical densities of the cell and as bar graphs (see right panel). The minimum drug concentration that inhibits growth by 80% relative to the drug-free growth control is indicated as MIC₈₀ for each drug. (b) Spot assays of M. smegmatis in the presence of EMB, INH, and RIF (62.5 ng/mL, 1 μg/mL, and 62.5 ng/mL) alone and in the presence of 2,2, BP, DFO, and BPS (35 μg/mL, 656 μg/mL, and 386 μg/mL) to confirm the effect of iron deprivation on susceptibilities of EMB, INH, and RIF.

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