Cephem compound having catechol group

A compound of the formula:

• wherein,
• X is —N═, —CH═, —C(—R5)═, —C(—Br)═ or —C(—Cl)═;
• R5 is lower alkyl or halo(lower)alkyl;
• W is —CH2—, —S— or —O—;
• U is —CH2—, —S— or —O— when W is —CH2—, or U is —CH2— when W is —S— or —O—;
• R1 and R2 are independently hydrogen, halogen, hydroxyl, carboxy, optionally substituted lower alkyl, optionally substituted carbocyclic group or optionally substituted heterocyclic group;
• or
• R1 and R2 are taken together with a neighboring atom to form optionally substituted carbocyclic group or optionally substituted heterocyclic group;
• R3 is hydrogen, —OCH3 or —NH—CH(═O);
• each R4 is independently hydrogen, halogen, hydroxyl, —CN, —C(═O)—R6, —C(═O)—OH, lower alkyl, halo(lower)alkyl or —OR6;
• k is an integer from 0 to 2;
• R6 is lower alkyl or halo(lower)alkyl;
• m is an integer from 0 to 2;
• Q is a single bond, optionally substituted carbocyclic group or optionally substituted heterocyclic group;
• G is i) —C(═O)— or ii) 5-membered heterocyclic group;
• wherein
• i) when G is —C(═O)—, then
• a) D is a single bond, —NH— or —R7—NH— wherein R7 is lower alkylene;
• and E is optionally substituted cyclic group selected from the following formulae (1) to (45);
• or
• b) D is a group of the formula:
• wherein q is 0 or 1, and E is a group of the following formula (46);
• and
• ii) when G is 5-membered heterocyclic group;
• then
• D is —CH2— or —CH2—CH2—, and E is a group of the following formula (10) in the following cyclic groups of the moiety E:
• wherein, p is an integer from 1 to 3, n is 1 or 2, and Rx is optionally substituted lower alkyl;
• provided that the following compounds (A-1) to (A-35) are excluded,
• or an ester, a protected compound at the amino on the ring in the 7-side chain, a pharmaceutically acceptable salt, or a solvate thereof.