Antibiotic resistance
Antibiotic resistance in "S. aureus" was uncommon when penicillin was first introduced in 1943. Indeed, the original Petri dish on which Alexander Fleming of Imperial College London observed the antibacterial activity of the "Penicillium" fungus was growing a culture of "S. aureus". By 1950, 40% of hospital "S. aureus" isolates were penicillin-resistant; by 1960, this had risen to 80%.