The present invention provides Cephem compounds having awide antimicrobial spectrum and potent antimicrobial activityagainst beta-lactamase producing Gram negative bacteria of theformula:(see Formula 1)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 a single bond, -NR7-, -CO-, -CO-NR7-, -NR7-CO-, -NR7-CO-NR7-,or the like；E is optionally substituted lower alkylene；F is a single bond or optionally substituted phenylene；R3, R4, R5 and R6 each is independently hydrogen, halogene,nitrile, or the like；or an ester, a compound protected at the amino on the ring inthe 7-side chain, a pharmaceutically acceptable salt, or asolvate thereof.
