5-Oxa-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, 7-[[[(difluoromethyl)thio]acetyl]amino]-7-methoxy-8-oxo-3-[[[1-[2-[(amino carbonyl)amino]-2-oxoethyl]-1H-tetrazol-5-yl]thio]methyl]-, cis-