A compound of formula I for use as a medicament, where the use is in the treatment of a bacterial infection, where formula I represents: ** Formula ** where: Y represents: ** Formula ** (ii ) -CF3； (iii) -N (C1-6 alkyl) 2； or (iv) C3-6 cycloalkyl； Nv, Nw, Nx, Ny and Nz independently represent -N>； = or -C (H)>； = but where only a maximum of three of Nv, Nw, Nx, Ny and Nz can represent -N>； =； n represents 0, 1 or 2； X1 and X2 independently represent -N- or -C (H) -； when X1 represents -N-, Q1 represents a direct link, -C (O) - or -S (O) 2-； when X1 represents -C (H) -, Q1 represents a direct link or -N (Rz) -； Rz represents hydrogen or C1-6 alkyl； Rx represents C1-6 alkyl (optionally substituted by one or more substituents that are selected from>； = O and A1), aryl or heteroaryl (the latter two groups being each optionally substituted by one or more substituents that are selected from A2 and A3 , respectively)； Ry, Ry1 and Ry2 independently represent hydrogen, halo, -CN, -OR10, -N (R11) (R12) or C1-6 alkyl (optionally substituted by one or more halo atoms)； A1, A2, A3 and A4 independently represent halo, -CN, -OR1, -S (O) 0-2 C1-3alkyl, C1-6alkyl (optionally substituted by one or more halo substituents), heterocycloalkyl (optionally substituted by one or more substituents that are selected from C1-3alkyl and halo), aryl or heteroaryl (the latter two groups being optionally substituted by one or more substituents that are selected from B1 and B2, respectively)； each R1 and R10 independently represent hydrogen, C1-6 alkyl (optionally substituted by one or more halo substituents), aryl or heteroaryl (the latter two groups being optionally substituted by one or more substituents that are selected from halo, C1-3 alkyl and -O-C1-3 alkyl)； R11 and R12 independently represent hydrogen or C1-6 alkyl； B1 and B2 independently represent halo, - CN, C1-6 alkyl (optionally substituted by one or more halo atoms), -OH or -O-C1-6 alkyl (optionally substituted by one or more
