2,2,2-Trichloroethyl 6-[[3-(2-chlorophenyl)-5-methyl-1,2-oxazole-4-carbonyl]amino]-3-methyl-3-[(1-methyltetrazol-5-yl)sulfanylmethyl]-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate