Abstract
Introduction:
The objective of this study was to compare the activity of ciprofloxacin, levofloxacin, moxifloxacin, gatifloxacin and ofloxacin against Pseudomonas aeruginosa by determining the mutant prevention concentration (MPC).
Methods:
Thirty-four clinical isolates of Pseudomonas aeruginosa causing nosocomial infection were studied. MPC values were determined using an inoculum of 10(10) cfu/mL on Mueller-Hinton plates with serial dilutions of the antibiotics. The microorganisms were classified according to whether the patients had been previously treated with fluoroquinolones or not.
Results:
The fluoroquinolone with the lowest MPC values was ciprofloxacin, followed by levofloxacin. Analysis of strains from patients previously treated with fluoroquinolones showed persistent susceptibility according to the CLSI criteria, but with lower activity of all the drugs.
Conclusions:
Although the microorganism remained susceptible to fluoroquinolones according to classical methods, the suitability of using these drugs in patients with severe infection and a history of fluoroquinolone use should be evaluated.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Anti-Bacterial Agents / administration & dosage
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Anti-Bacterial Agents / pharmacology*
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Anti-Bacterial Agents / therapeutic use
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Aza Compounds / administration & dosage
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Aza Compounds / pharmacology
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Ciprofloxacin / administration & dosage
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Ciprofloxacin / pharmacology
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Cross Infection / drug therapy
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Cross Infection / microbiology
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Dose-Response Relationship, Drug
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Drug Resistance, Bacterial / genetics
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Fluoroquinolones / administration & dosage
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Fluoroquinolones / pharmacology*
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Fluoroquinolones / therapeutic use
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Gatifloxacin
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Genes, Bacterial / drug effects
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Humans
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Levofloxacin
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Microbial Sensitivity Tests
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Moxifloxacin
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Mutagenicity Tests
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Mutation / drug effects*
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Ofloxacin / administration & dosage
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Ofloxacin / pharmacology
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Pseudomonas Infections / drug therapy
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Pseudomonas Infections / microbiology
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Pseudomonas aeruginosa / drug effects*
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Pseudomonas aeruginosa / genetics
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Pseudomonas aeruginosa / isolation & purification
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Quinolines / administration & dosage
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Quinolines / pharmacology
Substances
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Anti-Bacterial Agents
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Aza Compounds
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Fluoroquinolones
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Quinolines
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Ciprofloxacin
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Levofloxacin
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Ofloxacin
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Gatifloxacin
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Moxifloxacin