| abstract |
Novel beta-lactam compound of the formula [1]:wherein R1 is lower alkyl or hydroxy-substituted lower alkyl, R2 is H or lower alkyl, X is O or, S, R3 is H, metal or protecting group, W is a 6- or 7-membered nitrogen-containing heterocycle optionally being substituted at carbon atoms. Said beta-lactam compound shows excellent antibacterial activity against Gram-positive bacteria, particularly against methicillin-resistant Staphylococcus aureus and methicillin-resistant and coagulase-negative Staphylococcus aureus. |