Catalyzes the sodium-dependent uptake of extracellular L-proline (By similarity). Since most S.aureus strains are L-proline auxotrophs, this transporter may aid the bacterial persistence during an infection of tissues with low proline concentrations (PubMed:9453610). L-proline(in) + Na(+)(in) = L-proline(out) + Na(+)(out) Up-regulated by high osmotic environment, such as increasing concentrations of NaCl, and low L-proline concentrations. Cells lacking this gene display an approximate 33% overall decline in L-proline uptake and exhibit significantly reduced virulence in several animal models, thus showing a negative impact on the ability of this pathogen to survive in vivo. Belongs to the sodium:solute symporter (SSF) (TC 2.A.21) family.