Broadly Protective Vaccine for <i>Staphylococcus aureus</i> Based on an in Vivo-Expressed Antigen

TLDR

Vaccines targeting antigens preferentially expressed during human infection have not been reported, yet S. aureus produces the surface polysaccharide PNSG in vivo while most strains lack in‑vitro expression. The study aims to assess PNSG as a vaccine candidate against S. aureus infection.

Abstract

Vaccines based on preferential expression of bacterial antigens during human infection have not been described. Staphylococcus aureus synthesized poly- N -succinyl β-1-6 glucosamine (PNSG) as a surface polysaccharide during human and animal infection, but few strains expressed PNSG in vitro. All S. aureus strains examined carried genes for PNSG synthesis. Immunization protected mice against kidney infections and death from strains that produced little PNSG in vitro. Nonimmune infected animals made antibody to PNSG, but serial in vitro cultures of kidney isolates yielded mostly cells that did not produce PNSG. PNSG is a candidate for use in a vaccine to protect against S. aureus infection.