Cephalosporin antibacterial compound and preparation method therefor

A compound of formula I or a pharmaceutically acceptable salt thereof,

• wherein,
• X is N, CH or C—Cl;
• T is S, S═O, CH2 or O;
• E is
• wherein R1 and R2 are each independently selected from the group consisting of hydrogen, halogen, phenyl, alkylthio, and alkyl optionally substituted with carbamoyl;
• R11 and R12 are each independently selected from the group consisting of hydrogen, carboxyl, and alkyl optionally substituted with carbamoyl;
• m is an integer of 1-5;
• F is a single bond;
• A is C1-C6 alkylene, C2-C6 alkenylene or C2-C6 alkynylene;
• each R5 is independently selected from the group consisting of halogen, hydroxy, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl and C1-C6 haloalkoxy;
• G1 is
• R1′ and R2′ are each independently selected from the group consisting of hydrogen, halogen, hydroxy, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl and C1-C6 haloalkoxy;
• R3 is C1-C6 alkyl substituted with
• R3′ is selected from the group consisting of hydrogen, hydroxy, C1-C6 alkyl and C1-C6 alkoxy, wherein the alkyl and alkoxy are optionally substituted with one or more substituents selected from the group consisting of C1-C6 alkyl, halogen, hydroxy, sulfhydryl, —NRiRj,
• oxo, thio, —C(O)Rk, —C(O)ORk, —C(S)Rk, nitro, cyano, C1-C6 alkoxy and C1-C6 alkylthioether group;
• each Rm is independently selected from the group consisting of hydrogen, C1-C6 alkyl, C1-C6 alkoxy, hydroxy, 6- to 10-membered aryl and 5- to 8-membered heteroaryl, wherein the alkyl, alkoxy, aryl and heteroaryl are optionally substituted with one or more substituents selected from the group consisting of C1-C6 alkyl, halogen, hydroxy, sulfhydryl, amino, carboxyl, nitro, cyano and C1-C6 alkoxy;
• each R4 is independently selected from the group consisting of halogen, hydroxy, sulfhydryl and —NRiRj;
• Ri and Rj are each independently selected from the group consisting of hydrogen, hydroxy, C1-C6 alkyl and C1-C6 alkoxy;
• each Rk is independently selected from the group consisting of hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, hydroxy, C1-C6 alkoxy and —NRiRj, wherein the alkyl, haloalkyl and alkoxy are optionally substituted with one or more substituents selected from the group consisting of C1-C6 alkyl, halogen, hydroxy, sulfhydryl, —NRiRj, oxo, thio, carboxyl, nitro, cyano, C1-C6 alkoxy, C1-C6 alkylthioether group, 3- to 6-membered cycloalkyl, 3- to 6-membered heterocyclyl, 6- to 10-membered aryl and 5- to 8-membered heteroaryl;
• p is an integer of 0-5;
• q is an integer of 0-5;
• x is 3;
• n is an integer of 0-3.