title: Concentration-dependent synergy and antagonism between cefoperazone and imipenem against methicillin-resistant Staphylococcus aureus.
abstract: By the agar dilution checkerboard method, striking synergy between cefoperazone and imipenem was observed with 32 strains of methicillin-resistant Staphylococcus aureus (fractional inhibitory concentration indices, < or = 0.03 to 0.34; mean, 0.12 +/- 0.08). By the double-disk diffusion method, the synergy was confirmed, but about 60% of strains showed antagonism manifest by truncation of the zone of inhibition around cefoperazone. The mechanism may involve auxiliary factors distinct from those essential for the expression of methicillin resistance.
authors.affiliation: Department of Pathology, University of Florida, Gainesville 32610, USA.
authors.forename: K H
authors.initials: KH
authors.lastname: Rand
authors.forename: P
authors.initials: P
authors.lastname: Brown
mesh_terms: D002438:Cefoperazone / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004357:Drug Synergism; D015378:Imipenem / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D016106:Methicillin Resistance; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D015378:Imipenem; D002438:Cefoperazone