The invention relates to antibacterial compounds of formula (I), wherein U1 represents N or CH, U2 represents N or CH, U3 represents N or CH, it being understood that at most two of U1, U2, U3 can represent N at the same time; V1 represents N or CH, V2 represents N, CH or C(OH) and V3 represents N, CH or C(OH), it being understood that at most two of V1, V2 and V3 can represent N at the same time; the dotted line "----- " represents a bond or is absent; X represents CH or N; and Q represents O or S. It further relates pharmaceutical compositions containing these compounds and the uses of these compounds in the manufacture of medicaments for the treatment of bacterial infections. These compounds are useful antimicrobial agents effective against a variety of human and veterinary pathogens including among others Gram-positive and Gram-negative aerobic and anaerobic bacteria.