(pharmacology) A glycopeptide antibiotic C₆₆H₇₅Cl₂N₉O₂₄ produced by the actinomycete Amycolaptosis orientalis, used in the form of its hydrochloride C₆₆H₇₅Cl₂N₉O₂₄·HCl against Gram-positive bacteria, especially staphylococci resistant to meticillin and enterococci.