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 cover all these areas and instead focuses on the use of antibiotics for growth promotion, which has been banned in Europe since 2006, and on legislation regarding antibiotic use in farm animals in the USA. In 2013, the CDC finalized and released a report detailing antibiotic resistance and classified the top 18 resistant bacterium as either being urgent, serious or concerning threats. Of those organisms, three ("C. diff", carbapanem-resistant enterobacteriaceae, and "Neisseria gonorrhoeae") have been classified as urgent threats and require more monitoring and prevention. In the US alone, more than 2 million people are diagnosed with antibiotic-resistant infections and