[Mini review: a factor enhanced the antibacterial effect of beta-lactams on methicillin-resistant Staphylococcus aureus].

We found a factor (Factor T) in aged mixtures of tungstate and phosphate which greatly enhances the antibacterial effects of beta-lactams on methicillin-resistant Staphylococcus aureus (MRSA), while Factor T alone did not strongly inhibit bacterial growth. The effect on methicillin-susceptible S.aureus was weak. There was no synergism of Factor T with other classes of antibiotics, nor with other groups of bacteria. Factor T is probably a complex of phosphate and tungstate, and reduced the expression of penicillin-binding protein-2', thus sensitizing the MRSA strains to beta-lactams.