Histoplasma Requires SID1, a Member of an Iron-Regulated Siderophore Gene Cluster, for Host Colonization
HcLH95 (WT+vector), HcLH97 (sid1Δ+vector), HcLH103 (WT+SID1), and HcLH106 (sid1Δ+SID1) were used to infect C57BL/6J bone-marrow-derived macrophages at a multiplicity of infection of 5. Macrophages were lysed at t = 0, 6, 24, and 48 hours, and plated for H. capsulatum colony-forming units (CFUs) on HMM. CFUs were normalized to the zero time point. Infected macrophages were incubated in either BMM (A) or BMM+100 µM FeSO4 (B) Data from a representative time course is shown. The average of three platings+/−standard error of the mean is shown. Significance was determined using ANOVA with Bonferroni Multiple Comparisons Test. Comparison of wt+vector and sid1Δ+vector at 48 hours has a p<0.001. The experiment was repeated three times with two independently isolated sid1Δ strains, as well as four independently isolated sid1Δ+SID1 strains. (C) The average CFU at 48 hours of three independent infections+/−standard error of the mean is shown. White bars indicate CFUs from infected macrophages incubated in BMM, grey bars indicate macrophages incubated in BMM+100 µM FeSO4. Significance was determined for the influence of genotype (WT versus sid1Δ) and iron using three-way ANOVA. Genotype influence, *: p-value<0.05.