Figure 4

Growth of H. influenzae strains with human hemoglobin as the sole heme source. Growth of the H. influenzae strain Rd KW20, the dppC insertion mutant strain TMV1262 and the complemented dppC mutant strain HI2208 in hdBHI supplemented with human hemoglobin-haptoglobin complex as the sole heme source. Wildtype strain Rd KW20 with human hemoglobin-haptoglobin complex at 10 μg ml^-1 hemoglobin equivalent (solid triangles) and at 5 μg ml^-1hemoglobin equivalent (solid circles). The dppC insertion mutant strain TMV1262 with human hemoglobin-haptoglobin complex at 10 μg ml^-1hemoglobin equivalent (open triangles) and at 5 μg ml^-1 hemoglobin equivalent (open circles). The complemented dppC mutant strain HI2208 with human hemoglobin-haptoglobin complex at 10 μg ml^-1hemoglobin equivalent (solid squares) and at 5 μg ml^-1 hemoglobin equivalent (open squares). Results are mean ± SD for quintuplicate results from representative experiments. The Kruskal-Wallis test was used to compare growth of Rd KW20 and TMV1262 or to compare growth of TMV1262 and HI2208 over the entire 24 hour growth period at either concentration of hemoglobin-haptoglobin (P < 0.0001 for all comparisons).