Beta-lactamase inhibitors: relation between kinetic data and in-vitro synergism studies.

Because of the need for control of beta-lactamase-mediated resistance and the recent development of tazobactam, the author has examined the inhibitors of various beta-lactamases for their effectiveness. On the basis of the kinetic data, tazobactam exhibited the highest affinity to various beta-lactamases. A combination with tazobactam was found to enhance the effectiveness of piperacillin against S. aureus producing penicillinase, E. coli producing TEM-1 or TEM 2 enzymes and class I beta-lactamase-derepressed isolates of E. cloacae, Serratia spp. and C. freundii, however not P. aeruginosa, while there was no marked synergism in beta-lactamase-derepressed clones of K. oxytoca.