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 stereochemically isomeric form thereof, a tautomeric form thereof or a N-oxide form thereof. Several of these compounds are also claimed as such. Further the combination of the above compounds with other antibacterial agents is described