A compound represented by general formula (1) (wherein R 1 represents a hydrogen atom, an optionally substituted C 1-6 alkyl group or the like R 2 represents a hydrogen atom, an optionally substituted C 1-6 alkyl group or the like R 3 represents a hydrogen atom or an optionally substituted C 1-6 alkyl group R 4 represents a hydrogen atom, an optionally substituted C 1-6 alkyl group or the like X 1 represents an optionally substituted C 2-6 alkynylene group or the like A represents an optionally substituted bivalent aromatic hydrocarbon group or the like X 2 represents an optionally substituted C 1-6 alkylene group or the like Y 1 represents an oxygen atom or the like and R 5 represents a hydrogen atom or the like) or a salt thereof is useful as an antibacterial agent.
