γ Irradiation Alters the <i>Staphylococcus aureus</i> Proteome and Enhances Pathogenicity

<i>Staphylococcus aureus</i> (<i>S. aureus</i>) infection has become one of the most common and severe complications among cancer patients. The impact of γ radiation from radiotherapy on <i>S. aureus</i>'s growth and virulence is not yet fully understood. In this study, <i>S. aureus</i> 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 <i>S. aureus</i> were identified by using data-independent acquisition (DIA) proteomic technology. To investigate the consequences of proteome alternations induced by γ irradiation in <i>S. aureus</i>, functional enrichment analysis, pathway enrichment analysis, and protein-protein interaction network analysis were performed. Differentially expressed proteins (DEPs) in the irradiated <i>S. aureus</i> and its descendants were primarily enriched in lipoteichoic acid biosynthesis, <i>S. aureus</i> 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 <i>S. aureus</i>, likely resulting in increased pathogenicity.