he only other class of gyrase inhibitors which has been introduced into clinical use are the aminocoumarins. Novobiocin (Fig. 1) was discovered in the 1950s in screening programs for antibiotics produced by microorganisms. It was introduced into human anti-infective therapy in 1964 under the name Albamycin® by the Upjohn company and used for the treatment of Staphylococcus aureus infections, including multiresistant MRSA strains. Novobiocin is also active against Borrelia burgdorferi, the causative agent of Lyme disease ( Samuels and Garon, 1993).