Abstract
Timed killing kinetic studies were performed with ciprofloxacin in combination with aztreonam, ceftazidime, piperacillin/tazobactam, and ticarcillin/clavulanic acid against three isolates each of Klebsiella pneumoniae, Enterobacter cloacae, Serratia marcescens, and Pseudomonas aeruginosa. Each antimicrobial agent in the combination was tested at its MIC and at one-half and one-quarter of its MIC. Colony counts were determined at 0, 3, 5, and 7 hours. Synergy occurred most frequently at 7 hours and, when present, was most likely to occur when ciprofloxacin and the beta-lactam were tested at concentrations equal to their respective MICs. Synergy after 3 hours of incubation was not predictive of a synergestic interaction at 5 or 7 hours. Antagonism was noted in several instances, particularly when ciprofloxacin and the beta-lactam were combined at one-quarter of their respective MICs.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Anti-Bacterial Agents / pharmacology*
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Anti-Infective Agents / pharmacology*
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Aztreonam / pharmacology
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Ceftazidime / pharmacology
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Cephalosporins / pharmacology
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Ciprofloxacin / pharmacology*
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Clavulanic Acid
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Clavulanic Acids / pharmacology*
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Drug Interactions
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Drug Therapy, Combination
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Enterobacter cloacae / drug effects*
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Enzyme Inhibitors / pharmacology
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Kinetics
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Klebsiella pneumoniae / drug effects*
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Microbial Sensitivity Tests*
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Monobactams / pharmacology
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Penicillanic Acid / analogs & derivatives
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Penicillanic Acid / pharmacology
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Penicillins / pharmacology
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Piperacillin / pharmacology
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Pseudomonas aeruginosa / drug effects*
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Serratia marcescens / drug effects*
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Tazobactam
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Ticarcillin / pharmacology
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Time Factors
Substances
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Anti-Bacterial Agents
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Anti-Infective Agents
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Cephalosporins
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Clavulanic Acids
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Enzyme Inhibitors
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Monobactams
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Penicillins
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Clavulanic Acid
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Ciprofloxacin
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Penicillanic Acid
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Ceftazidime
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Ticarcillin
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Aztreonam
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Tazobactam
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Piperacillin