<;P>;PROBLEM TO BE SOLVED: To provide a new compound having high antibacterial activity on a wide variety of pathogenic bacteria including drug-resistant bacteria and livestock pneumonia-causing bacteria, to provide a tautomer and/or a salt thereof, and to provide methods for producing them. <;P>;SOLUTION: The new compound is amycolamicin as a nitrogen-containing heterocyclic ring-containing glycoside obtained from the cultured product of Amycolatopsis sp. MK575-fF5 strain microorganism (FERM P-21465) belonging to the genus Amycolatopsis. A tautomer and/or a salt thereof, and methods for producing them, are also provided, respectively. <;P>;COPYRIGHT: (C)2009,JPO&INPIT