peptide vancomycin Vancomycin A complex glycopeptide from Streptomyces orientalis. It inhibits a specific step in the synthesis of the peptidoglycan layer in the Gram-positive bacteria Staphylococcus aureus and Clostridium difficile. (3S,6R,7R,11R,23S,26S,30aS,36R,38aR)-44-[2-O-(3-amino-2,3,6-trideoxy-3-C-methyl-alpha-L-lyxo-hexopyranosyl)-beta-D-glucopyranosyloxy]-3-(carbamoylmethyl)-10,19-dichloro-2,3,4,5,6,7,23,25,26,36,37,38,38a-tetradecahydro-7,22,28,30,32-pentahydroxy-6-(N-methyl-D-leucyl)-2,5,24,38,39-pentaoxo-1H,22H-23,36-(epiminomethano)-8,11:18,21-dietheno-13,16:31,35-di(metheno)[1,6,9]oxadiazacyclohexadecino[4,5-m][10,2,16]benzoxadiazacyclotetracosine-26-carboxylic acid VANCOMYCIN