5-{[(3E)-4-(2-furyl)-5-oxo-3-aza-2-oxapent-3-en-5-yl]amino}-2-carbamoyl-10-[(carbamoyloxidanyl)methyl]-8-[(3E)-7-carboxy-4-(2-furyl)-5-oxo-3,6-diaza-2-oxahept-3-en-7-yl]-6-oxo-4,4a,5,6,10,11b-hexahydro[1,4]thiazino[2',3':3,4]pyrido[1,2-c][1,3]thiazine-11b-carboxylic acid