ABSTRACT
Bacteria may become resistant to -lactam antibiotics by one or more of three mechanisms: (1) production of -lactamases, which hydrolyze the -lactam ring, rendering it inactive; (2) failure of the antibiotic to reach its site of action (i.e., alteration of bacterial cell wall permeability such that -lactam antibiotic cannot reach its PBP target); and (3) production of altered PBPs that have a low affinity for -lactam antibiotics.
