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 are among the few viable antibiotics. Antibiotics have no effect on viral infections such as the common cold. They are also ineffective against sore throats, which are usually viral and self-resolving. Most cases of bronchitis (90–95%) are viral as well, passing after a few weeks—the use of antibiotics against bronchitis is superfluous and can put the patient at risk of suffering adverse reactions. Official guidelines by the American Heart Association for dental antibiotic prophylaxis call for the administration of antibiotics to prevent infective endocarditis. Though the current (2007) guidelines dictate more restricted antibiotic use, many dentists and dental patients follow