ABSTRACTDuring infection, pathogens must obtain all inorganic nutrients, such as phosphate, from the host. Despite the essentiality of phosphate for all forms of life, howStaphylococcus aureusobtains this nutrient during infection is unknown. Differing fromEscherichia coli, the paradigm for bacterial phosphate acquisition, which has two inorganic phosphate (Pi) importers, genomic analysis suggested thatS. aureuspossesses three distinct Pitransporters: PstSCAB, PitA, and NptA. WhilepitAandnptAare expressed in phosphate-replete media, expression of all three transporters is induced by phosphate limitation. The loss of a single transporter did not affectS. aureus. However, disruption of any two systems significantly reduced Piaccumulation and growth in divergent environments. These findings indicate that PstSCAB, PitA, and NptA have overlapping but nonredundant functions, thus expanding the environments in whichS. aureuscan successfully obtain Pi. Consistent with this idea, in a systemic mouse model of disease, loss of any one transporter did not decrease staphylococcal virulence. However, loss of NptA in conjunction with either PstSCAB or PitA significantly reduced the ability ofS. aureusto cause infection. These observations suggest that Piacquisition via NptA is particularly important for the pathogenesis ofS. aureus. While our analysis suggests that NptA homologs are widely distributed among bacteria, closely related less pathogenic staphylococcal species do not possess this importer. Altogether, these observations indicate that Piuptake byS. aureusdiffers from established models and that acquisition of a third transporter enhances the ability of the bacterium to cause infection.
Acquisition of the Phosphate Transporter NptA Enhances Staphylococcus aureus Pathogenesis by Improving Phosphate Uptake in Divergent Environments
