Which is NOT TRUE with regards to antibiotic resistance in bacteria?

Plasmid mediated resistance can be transmitted both horizontally and veically. Routes of horizontal transfer of plasmid mediated resistance are conjugation, transduction and transformation. 3 main mechanisms of drug resistance: Production of beta lactamases: Most common mechanism of penicillin resistance in both gram +ve and -ve bacteria. Alteration of PBP (penicillin binding proteins ): Seen in gram +ve bacteria. This is the basis for methicillin resistance in MRSA also basis for penicillin resistance in pneumococci and enterococci. Impaired penetration: Seen only in gram -ve bacteria PBP are localised on outer surface of cell membrane and not on cell wall. PBP are essential for synthesis of cell wall.