(7aR,7R)-7-{[(4Z)-5-[2-({[(7aR,7R)-7-{[(4Z)-5-(2-{[(4Z,8R)-5-(2-amino-1,3-thiazol-4-yl)-2-carboxy-8-[(2R)-4-carboxylato-5-(pyridin-1-ium-1-ylmethyl)-2H,3H,6H-1,3-thiazin-2-yl]-2-methyl-6,9-dioxo-4,7-diaza-3-oxanon-4-en-9-yl]amino}-1,3-thiazol-4-yl)-2-carboxy-2-methyl-6-oxo-4-aza-3-oxahex-4-en-6-yl]amino}-4-carboxy-6-oxo-2,6,7,7a-tetrahydroazeto[2,1-b][1,3]thiazin-3-yl]methyl}amino)-1,3-thiazol-4-yl]-2-carboxy-2-methyl-6-oxo-4-aza-3-oxahex-4-en-6-yl]amino}-6-oxo-3-(pyridin-1-ium-1-ylmethyl)-2,6,7,7a-tetrahydroazeto[2,1-b][1,3]thiazine-4-carboxylate