The age of antibiotics began in September 1928, with the discovery of penicillin by Alexander Fleming (1881-1955), then a professor of bacteriology at St. Mary's Hospital in London. Previously there were no effective treatments against a range of bacterial infections from pneumonia to sepsis.
This is a companion discussion topic for the original content at https://www.worldhistory.org/article/2490/discovery-of-penicillin/.