The present disclosure describes Cephem compounds of the formula:wherein,X is N, CH or C—Cl；T is S or the like；A and G are lower alkylene or the like；B is a single bond or the like；D is optionally present, and when present is, —NR7—, —CO—, —CO—NR7—, —NR7—CO—, —NR7—CO—NR7—, or the like；F is optionally present, and when present is or phenylene；R3 and R4 are —OR8；R5 and R6 each is independently hydrogen, halogen, nitrile, or —OR8；or an ester at the carboxyl at the 7-position side chain or at the 4-position, a compound protected at the amino on the ring in the 7-side chain, a pharmaceutically acceptable salt, or a solvate thereof, which have a wide antimicrobial spectrum and have potent antimicrobial activity against beta-lactamase producing Gram negative bacteria.
