disodium (4R,5R,6S)-3-[(3S,5S)-5-[(3-carboxylatophenyl)carbamoyl]pyrro lidin-3-yl]sulfanyl-6-(1-hydroxyethyl)-4-methyl-7-oxo-1-azabicyclo[3.2 .0]hept-2-ene-2-carboxylate