·1943 Penicillin commercially available·1947 First resistance reported·1960s Switch to methicillin·1980s Methicillin resistance rising·1990s 35% of isolates resistant to methicillin·1990s Switch to vancomycin·1996 Vancomycin resistance reported·2000 Linezolid approved by the U.S. Food and Drug Administration·2002 Linezolid resistance reported