title: CP-45,899 in combination with penicillin or ampicillin against penicillin-resistant Staphylococcus, Haemophilus influenzae, and Bacteroides.
abstract: CP-45,899 is a new, semisynthetic beta-lactamase inhibitor. When tested alone, CP-45,899 displayed only weak antibacterial activity, with the notable exception of its potent action against penicillin-susceptible and -resistant Neisseria gonorrhoeae. A combination of 3.12 microgram of CP-45,899 per ml with 3.12 microgram of ampicillin per ml, tested in broth cultures, inhibited ca. 90% of resistant Staphylococcus and Haemophilus influenzae strains; similar data were obtained in a variety of media. The same combination of CP-45,899 with ampicillin or penicillin G inhibited 90% of Bacteroides fragilis as interpreted from agar dilution minimal inhibitory concentrations. Inhibitory concentrations of CP-45,899-ampicillin were bactericidal against H. influenzae strains and were as bactericidal as nafcillin or cephalothin against S. aureus. Ampicillin-resistant S. aureus, H. influenzae, and B. fragilis strains did not develop resistance to CP-45,899-ampicillin when transferred as many as six passages in the presence of a sublethal concentration of the combination.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology*; D001439:Bacteroides / Q000187:drug effects*; D003470:Culture Media; D004357:Drug Synergism; D006193:Haemophilus influenzae / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010397:Penicillanic Acid / Q000494:pharmacology*; D010403:Penicillin Resistance; D010406:Penicillins / Q000494:pharmacology*; D013210:Staphylococcus / Q000187:drug effects*; D013407:Sulbactam; D065093:beta-Lactamase Inhibitors
chemical_list: D003470:Culture Media; D010406:Penicillins; D065093:beta-Lactamase Inhibitors; D000667:Ampicillin; D010397:Penicillanic Acid; D013407:Sulbactam