In vitro activities of cefoperazone and sulbactam singly and in combination against cefoperazone-resistant members of the family Enterobacteriaceae and nonfermenters.
Among 28,000 isolates of the family Enterobacteriaceae and nonfermenters isolated at multiple medical centers, 1,084 (4%) were resistant to cefoperazone (MIC, greater than or equal to 64 micrograms/ml) and 1,711 (6%) exhibited cefoperazone MICs of 2 to 32 micrograms/ml. Ninety-six percent of these 2,795 isolates produced beta-lactamase, as determined by the nitrocefin test. Sulbactam alone (8 micrograms/ml) was inactive against 99.6% of the isolates other than Acinetobacter calcoaceticus and Pseudomonas cepacia. Sulbactam enhanced the activity of cefoperazone against 56% of the isolates of the family Enterobacteriaceae and 44% of the nonfermenters. In the presence of sulbactam concentrations of less than or equal to 8 micrograms/ml, 65% of the cefoperazone-resistant isolates had reductions in cefoperazone MICs of greater than or equal to 2 log2 dilution steps and were susceptible to less than or equal to 32 micrograms/ml. Antagonism was not observed.
Fass
R J
RJ
Department of Internal Medicine, Ohio State University College of Medicine, Columbus 43210.
Gregory
W W
WW
D'Amato
R F
RF
Matsen
J M
JM
Wright
D N
DN
Young
L S
LS
D001419:Bacteria / Q000187:drug effects; D002438:Cefoperazone / Q000494:pharmacology*; D004347:Drug Interactions; D004352:Drug Resistance, Microbial; D004755:Enterobacteriaceae / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D013407:Sulbactam / Q000494:pharmacology*
D002438:Cefoperazone; D013407:Sulbactam