5-Oxa-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,7-[[[(difluoromethyl)thio]acetyl]amino]-3-[[[1-(2-hydroxyethyl)-1H-tetrazol-5-yl]thio]methyl]-7-methoxy-8-oxo-, hydrate, (6R,7R)-