FIG 1.
The Austrian clinical isolates use Hb, Hb-Hp, and hemin as iron sources for growth. Strains were grown in mPGT medium that was optimized for the growth experiments; supplemental iron sources were added as indicated below the graph (see Materials and Methods for medium details and hemoprotein concentrations). The iron chelator EDDA was added to remove nonhemin iron from the growth medium, and growth was measured by OD600 at 48 ± 1 h. Results show the mean and standard deviation from at least three experiments; analysis of significance used GraphPad Prism v9.1.2 by unpaired t tests. ****, P < 0.0001; ***, P < 0.001; **, P < 0.005; *, P < 0.05.