Bacitracin blocks the transport of nag and nam across the cytoplasmic membrane to the cell wall. Like other antimicrobials that block cell wall synthesis, this would result in weak cell walls and cell lysis. Antimicrobilas that act by inhibiting cell wall synthesis include beta-lactams, vancomycin and cycloserine and isoniazid and ethambutol among others. They prevent bacteria from increasing amount of peptidoglycan, they have no effect on existing peptodoglycan layer and therefore are effective only for growing cells.
