Antibiotics are among the most widely prescribed drugs in both human and veterinary medicine. Furthermore, they are used to protect plants against bacterial and fungal diseases, to decontaminate the shells of eggs, and to improve weight gain and feed conversion in a variety of food animals. Many antibiotics, in addition, have been esseptial tools in the elucidation of specific cellular functions. Genetic engineering, for example, would not be what it is today without the use of antibiotics in the selection of easily determined genetic markers. Production of antibiotics involves a diverse...