The invention provides compounds for use in a method of treating and/or preventing a bacterial infection in a human or non-human mammal, said method comprising administration of said compound in combination with (either simultaneously, separately, or sequentially) a β-lactam antibiotic, wherein said compound has the general formula I:




(wherein:



Q is a lipophilic, zinc chelating moiety which is selective for Zn2+ ions and which comprises at least one, preferably two or more (e.g 2, 3 or 4), optionally substituted, unsaturated heterocyclic rings, e.g. 5 or 6-membered heterocyclic rings (such rings preferably include at least one heteroatom selected from N, S and O, preferably N); wherein any optional substituents may be selected from C1-6 alkyl, C1-6 alkoxy, halogen, nitro, cyano, amine, and substituted amine;
each L, which may be the same or different, is a covalent bond or a linker;
each W, which may be the same or different, is a non-peptidic hydrophilic group which comprises one or more hydroxy groups; and
x is an integer from 1 to 3)

or a stereoisomer, pharmaceutically acceptable salt or prodrug thereof.