Characterization of an NaCl-sensitive Staphylococcus aureus mutant and rescue of the NaCl-sensitive phenotype by glycine betaine but not by other compatible solutes

Staphylococcus aureus NaCl-sensitive mutants exhibiting Tn917-lacZ insertions were analyzed by Southern blotting to determine the osmoregulatory mechanisms of the pathogenic microbe. The Staphylococcus aureus mutants with Tn917-induced NaCl-sensitivity exhibited high levels of L-[14C]proline and [14C]glycine betaine uptake under hyperosmotic stress. The levels of K+, proline and glycine betaine uptake were also similar between wild-type and mutant strains. However, the production of NaCl stress proteins was impaired by the presence of glycine betaine.