NCIt definition : A semisynthetic penicillin with antibacterial activity. Pirbenicillin binds to and
inactivates penicillin-binding proteins (PBPs) located on the inner membrane of the
bacterial cell wall. Inactivation of PBPs interferes with the cross-linkage of peptidoglycan
chains necessary for bacterial cell wall strength and rigidity. This interrupts bacterial
cell wall synthesis and results in the weakening of the bacterial cell wall and causes
cell lysis.;