6-(1-hydroxyethyl)-2-(1-acetimidoylpyrrolidin-3-ylthio)-1-methyl-1-carbapen-2-em-3-carboxylic acid, 4S-(3(S*),4alpha,5alpha,6beta(S*))-isomer
6-(1-hydroxyethyl)-2-(1-acetimidoylpyrrolidin-3-ylthio)-1-methyl-1-carbapen-2-em-3-carboxylic acid, 4s-(3(s*),4alpha,5alpha,6beta(s*))-isomer