Pasteur, oxygen and the anaerobes revisited.

As a biochemist, Louis Pasteur focused on fermentation, demonstrating that it was a vital process. In 1860, he discovered anaerobic life and the strict anaerobes, particularly those responsible for butyric fermentation. Then, in spite of his lack of medical background, Pasteur turned to investigating the role of bacteria in human and animal diseases. In 1877, Pasteur and Joubert described for the first time a pathogenic anaerobe, the 'septic vibrio' (now Clostridium septicum). Not only was the bacterium cultivated, but the disease symptoms described and the disease experimentally reproduced. Pasteur also described what are now known as mixed anaerobic infections. A historical review of Pasteur's work is made in the light of our present knowledge of this field.