Antibiotic discovery and resistance timeline. Date of resistance identified: 1940 - Penicillins 1953 - Tetracyclines 1985 - Macrolides, Fluoroquinolones 1993 - Carbapenems. Date of discovery: 1928 - Penicillins 1948 - Tetracyclines, Macrolides 1985 - Carbapenems. 2010 was 30 years since a new class of antibiotics was last introduced