A β-lactamase inhibitor; inhibits hydrolysis of nitrocefin by KPC-2 β-lactamase from K. pneumoniae and AmpC β-lactamase from P. aeruginosa (IC50s = 210 and 465 nM, respectively); restores imipenem sensitivity to resistant clinical isolates of P. aeruginosa and K. pneumoniae (MIC50s = 0.25-2 and 8-16 μM in the presence and absence of MK-7655, respectively); produces a bacteriostatic effect in mouse thigh models of K. pneumoniae and P. aeruginosa infection when administered with imipenem and cilastatin (48.9 mg/kg per day)