The present invention relates to novel lactams of formulae (I) and (II). The present invention further relates to the use of these compounds in the treatment of microbial infections and microbial contamination of surfaces, particularly infections and surface contaminations characterised by biofilm formation. Further provided are compounds of formula (I) and (II) substituted with acrylate or methacrylate groups and their attachment to surfaces or polymers to inhibit microbial contamination.