Abstract
Antimicrobial lethality is promoted by reactive oxygen species (ROS), such as superoxide, peroxide, and hydroxyl radical. Pretreatment with subinhibitory concentrations of plumbagin or paraquat, metabolic generators of superoxide, paradoxically reduced killing for oxolinic acid, kanamycin, and ampicillin. These pretreatments also reduced an oxolinic acid-mediated ROS surge. Defects in SoxS MarA or AcrB eliminated plumbagin- and paraquat-mediated MIC increases but maintained protection from killing. Thus, superoxide has both protective and detrimental roles in response to antimicrobial stress.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Ampicillin / pharmacology*
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Anti-Bacterial Agents / pharmacology*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Dose-Response Relationship, Drug
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Drug Resistance, Bacterial / genetics
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Escherichia coli K12 / drug effects*
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Escherichia coli K12 / genetics
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Escherichia coli K12 / metabolism
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Escherichia coli Proteins / genetics
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Escherichia coli Proteins / metabolism
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Gene Expression Regulation, Bacterial*
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Kanamycin / pharmacology*
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Microbial Sensitivity Tests
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Multidrug Resistance-Associated Proteins / genetics
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Multidrug Resistance-Associated Proteins / metabolism
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Naphthoquinones / chemistry
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Oxolinic Acid / pharmacology*
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Paraquat / chemistry
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Superoxides / chemistry
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Superoxides / pharmacology*
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Trans-Activators / genetics
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Trans-Activators / metabolism
Substances
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AcrB protein, E coli
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Anti-Bacterial Agents
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DNA-Binding Proteins
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Escherichia coli Proteins
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MarA protein, E coli
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Multidrug Resistance-Associated Proteins
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Naphthoquinones
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Trans-Activators
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Superoxides
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SoxS protein, E coli
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Kanamycin
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Ampicillin
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Oxolinic Acid
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Paraquat
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plumbagin