A FACTOR FOUND IN AGED TUNGSTATE SOLUTION ENHANCED THE ANTIBACTERIAL EFFECT OF BETA-LACTAMS ON METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS

We have found a factor (Factor T) in aged mixtures of tungstate and ph osphate which greatly enhances the antibacterial effects of beta-lacta ms on both inducible and constitutive methicillin-resistant Staphyloco ccus aureus, but not on methicillin-susceptible S. aureus. Factor T al one did not strongly inhibit bacterial growth. There was no synergism of Factor T with other classes of antibiotics, nor with other groups o f bacteria, and it reduced the efficacy of aminoglycosides and tetracy cline. Upon preparation of Factor T, acidifying and heating the mixtur e of tungstate and phosphate resulted in a high yield and reproducibil ity, and no enhancing effect was observed when other anions such as su lfate or molybdate were used instead. Factor T is heat- and acid-stabl e but labile to alkalization, and is probably a complex of phosphate a nd tungstate.