(E)-Aztreonam;(E)-2-({[(2-Amino-4-thiazolyl){[(2S,3S)-2-methyl-4-oxo-1-sulfo-3-azetidinyl]carbamoyl}methylene]amino}oxy)-2-methylpropionic acid;2-[[(E)-[1-(2-Amino-4-thiazolyl)-2-[[(2S,3S)-2-methyl-4-oxo-1-sulfo-3-azetidinyl)amino]-2-oxoethylidene]amino]oxy]-2-methylpropanoic acid;The E isomer of amtriannan