A β-lactam antibiotic; active against B. fragilis, E. lentum, P. morbillorum, and F. nucleatum (MICs = 8, 4, 2, and 4 UG/ml, respectively); active against 10 strains of S. faecalis at 32 UG/ml; increases survival and reduces bacteremia in a rabbit model of S. faecalis endocarditis; completely eliminates lung P. morbillorum, E. lentum, and F. nucelatum, but not B. fragilis, in a rabbit model of pulmonary P. morbillorum, E. lentum, F. nucelatum, and B. fragilis infection at 300 mg/kg