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 use in livestock for not collecting enough information and data on antibiotic use in factory farms. From this, the GAO concluded that the FDA does not have enough information to create effective policy changes regarding antibiotic use. In response, the FDA insisted that more research was being conducted and voluntary efforts within the industry would solve the problem of antibiotic resistance. Few policies exist that limit antibiotic use on factory farms, and some proposed legislation in the US has failed to be adopted. In 2007, two federal bills (S. 549 and H.R. 962) aimed to phase out nontherapeutic antibiotics in U.S. food animal