Carbacephem β-lactam antibiotics having the following chemical structures (I) and (II) are disclosed:
including stereoisomers, pharmaceutically acceptable salts, esters and prodrugs thereof, wherein Ar
2
, R
1
, R
2
and R
3
are as defined herein. The compounds are useful for the treatment of bacterial infections, in particular those caused by methicillin-resistant
Staphylococcus
spp.