Antibiotic penicillin led to renewed interest in the search for antibiotic compounds with similar efficacy and safety. For their successful development of penicillin, which Fleming had accidentally discovered but could not develop himself, as a therapeutic drug, Chain and Florey shared the 1945 Nobel Prize in Medicine with Fleming. Florey credited Rene Dubos with pioneering the approach of deliberately and systematically searching for antibacterial compounds, which had led to the discovery of gramicidin and had revived Florey's research in penicillin. In 1939, coinciding with the start of World War II, Dubos had reported the discovery of the first naturally derived antibiotic,
Antibiotic misuse a lack of knowledge on which antibiotic use generates the most risk to humans, policies and regulations have been placed to limit any harmful effects, such as the potential of bacteria developing antibiotic resistance within livestock, and that bacteria transferring resistance genes to human pathogens On January 1, 2017, the FDA enacted legislation to require that all human medically important feed-grade antibiotics (many prior over-the-counter-drugs) become classified as Veterinary Feed Directive drugs (VFD). This action requires that farmers establish and work with veterinaries to receive a written VFD order. The effect of this act places a requirement on an established