Abstract
The synergistic interaction between Staphylococcus aureus and Candida albicans exacerbates polymicrobial infection severity and mortality compared to monomicrobial infections. C. albicans metabolism is known to enhance S. aureus virulence, whereas the role of S. aureus metabolic reprogramming in this cross-species synergy remains poorly defined. In this study, we demonstrate that C. albicans remodels S. aureus glycolytic pathways, thereby increasing its virulence in glucose-rich environments. C. albicans triggers metabolic reprogramming in S. aureus, characterized by a reduction of lactate and accumulation of upstream glycolytic intermediates, including 3-phosphoglycerate, 2-phospho-D-glycerate, and phosphoenolpyruvate. The metabolic reprogramming phenotype is glycolysis-dependent, which is evidenced by 2-deoxy-D-glucose-mediated inhibition of virulence enhancement. Addition of exogenous lactate lowers extracellular pH and reduces the hemolytic activity of S. aureus-C. albicans co-cultures. Inhibition of lactate dehydrogenase by oxamate or extracellular alkalinization with sodium hydroxide significantly increases hemolysis in S. aureus mono-cultures. S. aureus-C. albicans co-infections promote inflammatory cell infiltration but do not affect the quantity of S. aureus, indicating that increased toxin levels, rather than bacterial quantity, drive the enhanced virulence. Collectively, these findings indicate that C. albicans enhances S. aureus virulence through metabolic reprogramming. Targeting lactate metabolism or glycolytic intermediates may disrupt this cooperative interaction, offering a novel therapeutic strategy against these polymicrobial infections.