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 dentistry prophylaxis to prevent post-operative infections, resulting from bacteraemia, and infective endocarditis was practiced by dentists, especially in patients at high risk (i.e. with heart problems). However, according to new recommendations from the National Institution for Health and Care Excellence (NICE), antibiotic prophylaxis should not be offered for all patients at risk of infective endocarditis. This is due to the ever-increasing antibiotic resistance and there is no or very little evidence to show whether antibiotic prophylaxis is effective or ineffective against post-operative infections. Moreover, it is yet to be established whether the benefits of administering antibiotics prophylactically outweighs the inherent risks,