Reviewed by Emily Henderson, B.Sc. Mar 24 2020 Since the discovery of penicillin in 1928 by Sir Alexander Fleming, antibiotics have saved millions of lives from fatal infections world-wide. However, with time bacteria have developed mechanisms to escape the effects of antibiotics – they have become resistant. With fewer antibiotics available to treat resistant bacterial infections, the possibility of entering a pre-antibiotic era is looming ahead. .en.