Magnesium links starvation-mediated antibiotic persistence to ATP

Bacterial persisters emerge and increase in numbers over time as a bacterial culture grows from log phase to stationary phase. However, the underlying basis of the inevitable tendency is unclear. In this study, we investigated the role of nutrients in starvation-mediated persister formation of Staphylococcus aureus. By screening of nutrient components, we found that starvation-induced persister formation of log-phase cultures could be reversed by addition of magnesium (Mg²⁺) but not amino acids, nucleotides, or other salts. Further, deprivation of extracellular Mg²⁺ reduced cytoplasmic ATP, inducing persistence without affecting cytoplasmic Mg²⁺ or membrane potential. Finally, we showed that Mg²⁺ reduced expression of stationary cell marker genes, cap5A and arcA. These findings indicate a connection between Mg²⁺ levels and ATP, which represents metabolic status and mediates antibiotic persistence during growth.