Methicillin

**Semantic type:** Antibiotic|Pharmacologic Substance

**Definition:** A semisynthetic, narrow spectrum beta-lactamase-resistant penicillin antibiotic with bactericidal and beta-lactamase resistant activity. Methicillin binds to specific penicillin-binding proteins (BPBs) on the bacterial cell wall, thereby preventing the cross-linkage of peptidoglycans, which are critical components of the bacterial cell wall. This leads to an interruption of the bacterial cell wall and causes bacterial lysis.

**Synonyms:** - METHICILLIN