Use of a compound for the manufacture of a medicament for the treatment of a bacterial infection provided that the bacterial infection is other than a Mycobacterial infection, said compound being a compound of Formula (Ia) or (Ib) a pharmaceutically acceptable acid or base addition salt thereof, a quaternary amine thereof, a stereochemically isomeric form thereof, a tautomeric form thereof or a N-oxide form thereof, wherein R1 is hydrogen, halo, haloalkyl, cyano, hydroxy, Ar, Het, alkyl, alkyloxy, alkylthio, alkyloxyalkyl, alkylthioalkyl, Ar-alkyl or di(Ar)alkyl; p is 1, 2, 3 or 4; R2 is hydrogen, hydroxy, thio, alkyloxy, alkyloxyalkyloxy, alkylthio, mono or di(alkyl)amino or a radical of formula R3 is alkyl, Ar, Ar-alkyl, Het or Het-alkyl; R4 is hydrogen, alkyl or benzyl; R5 is hydrogen, halo, haloalkyl, hydroxy, Ar, alkyl, alkyloxy, alkylthio, alkyloxyalkyl, alkylthioalkyl, Ar-alkyl or di(Ar)alkyl; or two vicinal R5 radicals may be taken together to form together with the phenyl ring to which they are attached a naphthyl; r is 1, 2, 3, 4 or 5; R6 is hydrogen, alkyl, Ar or Het; R7 is hydrogen or alkyl; R5 is oxo; or R7 and R5 together form the radical —CH═CH—N═; Z is CH2 or C(═O).