γ Irradiation Alters the Staphylococcus aureus Proteome and Enhances Pathogenicity

Staphylococcus aureus (S. aureus) infection has become one of the most common and severe complications among cancer patients. The impact of γ radiation from radiotherapy on S. aureus's growth and virulence is not yet fully understood. In this study, S. aureus was exposed to γ radiation at a dose of 100 Gy, and its descendants were cultured under normal conditions. Proteome alternations of unirradiated, irradiated, and descendants of irradiated S. aureus were identified by using data-independent acquisition (DIA) proteomic technology. To investigate the consequences of proteome alternations induced by γ irradiation in S. aureus, functional enrichment analysis, pathway enrichment analysis, and protein-protein interaction network analysis were performed. Differentially expressed proteins (DEPs) in the irradiated S. aureus and its descendants were primarily enriched in lipoteichoic acid biosynthesis, S. aureus infection, two-component system, and cationic antimicrobial peptide resistance, suggesting an enhanced infection ability. A strong infection ability is typically associated with increased biofilm formation. Both the proteome study and the biofilm assay indicate that γ irradiation enhances the infection ability of S. aureus, likely resulting in increased pathogenicity.