Ernest Duchesne (May 30, 1874 - April 12, 1912) was a French physician who noted that certain moulds kill bacteria. He made this discovery thirty-two years before Alexander Fleming discovered the antibiotic properties of penicillin, a substance derived from those moulds, but his research went unnoticed.
He entered l'Ecole du Service de Santé Militaire de Lyon (the Military Health Service School of Lyon) in 1894. Duchesne's thesis, “Contribution à l’étude de la concurrence vitale chez les micro-organismes: antagonisme entre les moisissures et les microbes” (Contribution to the study of vital competition in micro-organisms: antagonism between moulds and microbes), that he defended in 1897 to get his doctorate degree, was the first study to consider the therapeutic capabilities of moulds resulting from their anti-microbial activity.
In particular, Duchesne studied the interaction between Escherichia coli and Penicillium glaucum, showing that the latter was able to completely eliminate the former in a culture containing only these two organisms. He also showed that an animal inoculated with a normally lethal dose of typhoid bacilli would be free of the disease if the animal was also inoculated with Penicillium glaucum. He urged more research but unfortunately his army service after getting his degree prevented any further research in this promising field.
Duchesne served a one year internship at Val de Grâce before he was appointed a 2nd class Major of Medicine in the 2nd Regiment de Hussards de Senlis. In 1901, he married Rosa Lassalas from Cannes. She died 2 years later of tuberculosis. In 1904, Duchesne contracted an unknown pulmonary disease; three years later, he was discharged from the army and sent to a care center in Amelie les Bains. Duchesne died at age 37 on April 12, 1912. He is buried next to his wife in the Cimetière du Grand Jas in Cannes.