methicillin Dimocillin Meticillinum antibiotic_resistance Meticilline ARO:0000015 meticillin PubChem:6087 ChEBI:6827 Methycillin Derived from penicillin to combat penicillin-resistance, methicillin is insensitive to beta-lactamases (also known as penicillinases) secreted by many penicillin-resistant bacteria. Methicillin is bactericidal, and acts by inhibiting the synthesis of the peptidoglycan layer of bacterial cell walls. The peptidoglycan layer is important for cell wall structural integrity, especially in Gram-positive organisms. CAS:61-32-5 ChEMBL:CHEMBL575 Staphcillin Metacillin Meticilina Methicillinum beta-lactamase resistant penicillin