(6R,7R)-7-[[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-[(1S)-1,2-dicarboxyethoxy]iminoacetyl]amino]-3-[[1-[2-(7-hydroxy-1,8-dioxo-3,4-dihydropyrido[1,2-a]pyrazin-2-yl)ethyl]pyrrolidin-1-ium-1-yl]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate