antibioticsbooks

Beta-Lactamase Inhibitor
Combinations
Agents: ampicillin/sulbactam, amoxicillin/
clavulanate, piperacillin/tazobactam,
ticarcillin/clavulanate
Though the aminopenicillins and antipseudomonal
penicillins have good intrinsic activity
against GNRs, they remain just as susceptible
to beta- lactamases as penicillin G. This means
that they are not useful against the vast majority
of staphylococci or many GNRs and anaerobes,
because these organisms have learned to
produce beta-lactamase. In other words, it seemed
we learned either how to make a penicillin resistant
to beta-lactamase, or how to make it more
active against GNRs, but not both. Beta-lactamase
inhibitors counter beta-lactamases; these drugs
mimic the structure of beta-lactams but have little
antimicrobial activity on their own. They bind to
beta-lactamases irreversibly, preventing the betalactamase
from destroying any beta-lactams that
are co-administered and enabling the therapeutic
beta-lactam to be effective.
When considering the activity of the beta-lactam/
beta-lactamase inhibitor combination, remember
that the beta-lactamase inhibitor only frees up
the beta-lactam to kill the organism—it doesn’t
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