Description
Daptomycin is used to selectively inhibit susceptible Gram-positive bacteria and to study membrane integrity, antibiotic resistance, and cell envelope stress responses in bacterial systems.
It is commonly incorporated into culture media or susceptibility assays to suppress sensitive organisms and to evaluate resistance mechanisms in species such as Enterococcus and Staphylococcus.
Daptomycin is a cyclic lipopeptide antibiotic that binds to bacterial membranes in a calcium dependent manner, inserts its lipid tail into the phospholipid bilayer, and causes rapid membrane depolarization. This disruption of membrane potential inhibits essential cellular processes, leading to bacterial cell death without direct lysis. Its unique membrane targeting mechanism makes it a valuable tool for investigating antimicrobial activity distinct from beta lactam or glycopeptide antibiotics.
Key Features and Advantages
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Membrane Targeting Mechanism: Disrupts cytoplasmic membrane potential in Gram-positive bacteria through calcium dependent insertion into the lipid bilayer.
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Distinct from Cell Wall Inhibitors: Provides an alternative mode of action compared to beta lactams and glycopeptides, supporting comparative resistance and physiology studies.
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Selective Activity Against Gram-Positive Organisms: Effective against many clinically relevant Gram-positive species, enabling focused suppression in mixed cultures.
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Rapid Bactericidal Effect: Induces quick membrane depolarization, making it useful for time course and kinetic antimicrobial studies.
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Defined Calcium Dependence: Activity requires physiologic concentrations of calcium ions, allowing controlled experimental modulation.
Common Applications and Usage Notes
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Antimicrobial Susceptibility Testing: Used in broth dilution and agar based assays to determine minimum inhibitory concentrations for Gram-positive isolates.
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Resistance Mechanism Studies: Applied in investigations of membrane adaptation, phospholipid remodeling, and genetic determinants of reduced susceptibility.
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Membrane Physiology Experiments: Utilized to examine membrane depolarization, ion flux, and stress response pathways.
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Comparative Antibiotic Studies: Enables evaluation of bacterial responses to membrane active agents versus cell wall synthesis inhibitors.
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Selective Suppression in Culture: Incorporated into media to inhibit susceptible Gram-positive contaminants where appropriate resistance markers are present.
Practical Tips
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Calcium Supplementation: Ensure appropriate calcium concentrations in media, as daptomycin activity is calcium dependent.
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Include Control Strains: Use well characterized susceptible and resistant strains to confirm activity and experimental consistency.
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Storage/Handling: Store powder format at room temperature.
Product Specifications
Daptomycin
Formula: C72H101N17O26
MW: 1620.67 g/mol
Storage/Handling: Store at room temperature.
PubChem CID: 16134395
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