Since Augmentin™ is ineffective against MRSA, it is already clear that direct penicillinase inhibitors are not the correct partner to combine with penicillin G. Moreover, using even high concentrations of sulbactam with penicillin G failed to cure all animals infected with MRSA. This is because irreversible inhibition of the antimicrobial by penicillinase prevents it from being fully available to act on the intended target -this is a major problem in using direct penicillinase inhibitors. Furthermore, sulbactam induces penicillinase expression. These data clearly demonstrate that blocking penicillinase expression is a preferable target for enhancement of penicillinase-sensitive β-lactams like penicillin G.