Effect of magnesium on the physiology of Staphylococcus aureus

The role of magnesium (Mg2+) in the metabolism of Staphylococcus aureus was studied using a chemically defined medium. At least 0.01 mM Mg2+ was required for any growth of S. aureus. Increasing concentration of Mg2+ up to 1.6mM steadily increased the bacterial growth. Glucose utilisation and acid production were also influenced by Mg2+. Excessive cobalt (Co2+) and zinc (Zn2+) were inhibitory to S. aureus growth and Mg2+ could reverse the inhibitory effect.