science & techanalysisOur World in Data1940s–1960s
Nearly two-thirds of antibiotic drug classes were discovered in the golden age from the 1940s to the late 1960s
The period from the early 1940s to the late 1960s is known as the golden age of antibiotics, when many of the drugs we still rely on were introduced. Nearly two-thirds of all antibiotic drug classes date from this era. Penicillin, first used widely in the 1940s, was followed by streptomycin, tetracyclines and many others. Most classes were found by screening soil microbes and fungi for compounds that kill bacteria.
Many antibiotics come from microbes that make chemicals to fight rival bacteria. Researchers grow these microbes, extract their compounds and test which ones kill or stop pathogens. Bacteria then evolve resistance through mutation and gene transfer, so each drug eventually loses effectiveness.
Almost no new classes have been discovered since the late 1960s, which is why antibiotic resistance is such a serious problem. Bacteria keep evolving defences, while the pipeline of new drugs has slowed.
Resistance has appeared against every antibiotic introduced, often within years, as with penicillin in the 1940s. This cycle of discovery and resistance is why researchers now warn about a post-antibiotic era.
